cu damascene process: Topics by WorldWideScience.org

Sample records for cu damascene process

Electromigration in Cu(Al) and Cu(Mn) damascene lines

Science.gov (United States)

Hu, C.-K.; Ohm, J.; Gignac, L. M.; Breslin, C. M.; Mittal, S.; Bonilla, G.; Edelstein, D.; Rosenberg, R.; Choi, S.; An, J. J.; Simon, A. H.; Angyal, M. S.; Clevenger, L.; Maniscalco, J.; Nogami, T.; Penny, C.; Kim, B. Y.

2012-05-01

The effects of impurities, Mn or Al, on interface and grain boundary electromigration (EM) in Cu damascene lines were investigated. The addition of Mn or Al solute caused a reduction in diffusivity at the Cu/dielectric cap interface and the EM activation energies for both Cu-alloys were found to increase by about 0.2 eV as compared to pure Cu. Mn mitigated and Al enhanced Cu grain boundary diffusion; however, no significant mitigation in Cu grain boundary diffusion was observed in low Mn concentration samples. The activation energies for Cu grain boundary diffusion were found to be 0.74 ± 0.05 eV and 0.77 ± 0.05 eV for 1.5 μm wide polycrystalline lines with pure Cu and Cu (0.5 at. % Mn) seeds, respectively. The effective charge number in Cu grain boundaries Z*GB was estimated from drift velocity and was found to be about -0.4. A significant enhancement in EM lifetimes for Cu(Al) or low Mn concentration bamboo-polycrystalline and near-bamboo grain structures was observed but not for polycrystalline-only alloy lines. These results indicated that the existence of bamboo grains in bamboo-polycrystalline lines played a critical role in slowing down the EM-induced void growth rate. The bamboo grains act as Cu diffusion blocking boundaries for grain boundary mass flow, thus generating a mechanical stress-induced back flow counterbalancing the EM force, which is the equality known as the "Blech short length effect."
Electromigration-induced drift in damascene and plasma-etched Al(Cu). II. Mass transport mechanisms in bamboo interconnects

Science.gov (United States)

Proost, Joris; Maex, Karen; Delacy, Luc

2000-01-01

We have discussed electromigration (EM)-induced drift in polycrystalline damascene versus reactive ion etched (RIE) Al(Cu) in part I. For polycrystalline Al(Cu), mass transport is well documented to occur through sequential stages : an incubation period (attributed to Cu depletion beyond a critical length) followed by the Al drift stage. In this work, the drift behavior of bamboo RIE and damascene Al(Cu) is analyzed. Using Blech-type test structures, mass transport in RIE lines was shown to proceed both by lattice and interfacial diffusion. The dominating mechanism depends on the Cu distribution in the line, as was evidenced by comparing as-patterned (lattice EM) and RTP-annealed (interface EM) samples. The interfacial EM only occurs at metallic interfaces. In that case, Cu alloying was observed to retard Al interfacial mass transport, giving rise to an incubation time. Although the activation energy for the incubation time was found similar to the one controlling Al lattice drift, for which no incubation time was observed, lattice EM is preferred over interfacial EM because it is insensitive to enhancing geometrical effects upon scaling. When comparing interfacial electromigration in RIE with bamboo damascene Al(Cu), with the incubation time rate controlling for both, the higher EM threshold observed for damascene was shown to be insufficient to compensate for its significantly increased Cu depletion rate, contrary to the case of polycrystalline Al(Cu) interconnects. Two factors were demonstrated to contribute. First, there are more metallic interfaces, intrinsically related to the use of wetting or barrier layers in recessed features. Second, specific to this study, the additional formation of TiAl3 at the trench sidewalls further enhanced the Cu depletion rate, and reduced the rate-controlling incubation time. A separate drift study on RIE via-type test structures indicated that it is very difficult to suppress interfacial mass transport in favor of lattice EM
High-etch-rate bottom-antireflective coating and gap-fill materials using dextrin derivatives in via first dual-Damascene lithography process

Science.gov (United States)

Takei, Satoshi; Sakaida, Yasushi; Shinjo, Tetsuya; Hashimoto, Keisuke; Nakajima, Yasuyuki

2008-03-01

The present paper describes a novel class of bottom antireflective coating (BARC) and gap fill materials using dextrin derivatives. The general trend of interconnect fabrication for such a high performance LSI is to apply cupper (Cu)/ low-dielectric-constant (low-k) interconnect to reduce RC delay. A via-first dual damascene process is one of the most promising processes to fabricate Cu/ low-k interconnect due to its wide miss-alignment margin. The sacrificial materials containing dextrin derivatives under resist for lithography were developed in via-first dual damascene process. The dextrin derivatives in this study was obtained by the esterification of the hydroxyl groups of dextrin resulting in improved solubility in the resist solvents such as propylene glycol monomethylether, propylene glycol monomethylether acetate, and ethyl lactate due to avoid the issue of defects that were caused by incompatability. The etch rate of our developed BARC and gap fill materials using dextrin derivatives was more than two times faster than one of the ArF resists evaluated in a CF4 gas condition using reactive ion etching. The improved etch performance was also verified by comparison with poly(hydroxystyrene), acrylate-type materials and latest low-k materials as a reference. In addition to superior etch performance, these materials showed good resist profiles and via filling performance without voids in via holes.
Crystal plasticity in Cu damascene interconnect lines undergoing electromigration as revealed by synchrotron x-ray microdiffraction

Science.gov (United States)

Budiman, A. S.; Nix, W. D.; Tamura, N.; Valek, B. C.; Gadre, K.; Maiz, J.; Spolenak, R.; Patel, J. R.

2006-06-01

Plastic deformation was observed in damascene Cu interconnect test structures during an in situ electromigration experiment and before the onset of visible microstructural damage (voiding, hillock formation). We show here, using a synchrotron technique of white beam x-ray microdiffraction, that the extent of this electromigration-induced plasticity is dependent on the linewidth. In wide lines, plastic deformation manifests itself as grain bending and the formation of subgrain structures, while only grain rotation is observed in the narrower lines. The deformation geometry leads us to conclude that dislocations introduced by plastic flow lie predominantly in the direction of electron flow and may provide additional easy paths for the transport of point defects. Since these findings occur long before any observable voids or hillocks are formed, they may have direct bearing on the final failure stages of electromigration.
Modeling and Measurement of Stress and Strain Evolution in Cu Interconnects

International Nuclear Information System (INIS)

Besser, Paul R.; Zhai, Charlie Jun

2004-01-01

The damascene fabrication method and the introduction of low-K dielectrics present a host of reliability challenges to Cu interconnects and fundamentally change the mechanical stress state of Cu lines used as interconnects for integrated circuits. In order to capture the effect of individual process steps on the stress evolution in the BEoL (Back End of Line), a process-oriented finite element modeling (FEM) approach was developed. In this model, the complete stress history at any step of BEoL can be simulated as a dual damascene Cu structure is fabricated. The model was calibrated with both wafer-curvature blanket film measurements and X-Ray diffraction (XRD) measurement of metal line stress. The Cu line stress evolution was simulated during the process of multi-step processing for dual damascene Cu/TEOS and Cu/low-k structures. The in-plane stress of Cu lines is nearly independent of subsequent processes, while the out-of-plane stress increases considerably with the subsequent process steps. The modeling results will be compared with recent XRD measurements and extended generically to illustrate the relative influence of the dielectric (ILD) modulus (E) and coefficient of thermal expansion (CTE) on strain/stress in the Cu lines. It will be shown that the stress magnitude and state (hydrostatic, deviatoric) depend on ILD properties. The stress along the line length (longitudinal) is substrate-dominated, while the transverse and normal stresses vary with both CTE and modulus of the dielectric. The hydrostatic stress is primarily determined by ILD modulus and is nearly independent of the ILD CTE, while the Von Mises stress depends on both CTE and E of the ILD. The stress of the Cu line tends to be more deviatoric with spin-on low K ILDs, and more hydrostatic with oxide encapsulation
Multilevel integration of patternable low-κ material into advanced Cu BEOL

Science.gov (United States)

Lin, Qinghuang; Chen, S. T.; Nelson, A.; Brock, P.; Cohen, S.; Davis, B.; Fuller, N.; Kaplan, R.; Kwong, R.; Liniger, E.; Neumayer, D.; Patel, J.; Shobha, H.; Sooriyakumaran, R.; Purushothaman, S.; Spooner, T.; Miller, R.; Allen, R.; Wisnieff, R.

2010-04-01

In this paper, we wish to report, for the first time, on a simple, low-cost, novel way to form dual-damascene copper (Cu) on-chip interconnect or Back-End-Of-the-Line (BEOL) structures using a patternable low dielectric constant (low-κ) dielectric material concept. A patternable low-κ dielectric material combines the functions of a traditional resist and a dielectric material into one single material. It acts as a traditional resist during patterning and is subsequently converted to a low-κ dielectric material during a post-patterning curing process. No sacrificial materials (separate resists or hardmasks) and their related deposition, pattern transfer (etch) and removal (strip) are required to form dual-damascene BEOL patterns. We have successfully demonstrated multi-level dual-damascene integration of a novel patternable low-κ dielectric material into advanced Cu BEOL. This κ=2.7 patternable low-κ material is based on the industry standard SiCOH-based (silsesquioxane polymer) material platform and is compatible with 248 nm optical lithography. Multilevel integration of this patternable low-κ material at 45 nm node Cu BEOL fatwire levels has been demonstrated with very high electrical yields using the current manufacturing infrastructure.
Multilevel Dual Damascene copper interconnections

Science.gov (United States)

Lakshminarayanan, S.

Copper has been acknowledged as the interconnect material for future generations of ICs to overcome the bottlenecks on speed and reliability present with the current Al based wiring. A new set of challenges brought to the forefront when copper replaces aluminum, have to be met and resolved to make it a viable option. Unit step processes related to copper technology have been under development for the last few years. In this work, the application of copper as the interconnect material in multilevel structures with SiO2 as the interlevel dielectric has been explored, with emphasis on integration issues and complete process realization. Interconnect definition was achieved by the Dual Damascene approach using chemical mechanical polishing of oxide and copper. The choice of materials used as adhesion promoter/diffusion barrier included Ti, Ta and CVD TiN. Two different polish chemistries (NH4OH or HNO3 based) were used to form the interconnects. The diffusion barrier was removed during polishing (in the case of TiN) or by a post CMP etch (as with Ti or Ta). Copper surface passivation was performed using boron implantation and PECVD nitride encapsulation. The interlevel dielectric way composed of a multilayer stack of PECVD SiO2 and SixNy. A baseline process sequence which ensured the mechanical and thermal compatibility of the different unit steps was first created. A comprehensive test vehicle was designed and test structures were fabricated using the process flow developed. Suitable modifications were subsequently introduced in the sequence as and when processing problems were encountered. Electrical characterization was performed on the fabricated devices, interconnects, contacts and vias. The structures were subjected to thermal stressing to assess their stability and performance. The measurement of interconnect sheet resistances revealed lower copper loss due to dishing on samples polished using HNO3 based slurry. Interconnect resistances remained stable upto 400o
Effect of Rosa damascene aromatherapy on sleep quality in cardiac patients: a randomized controlled trial.

Science.gov (United States)

Hajibagheri, Ali; Babaii, Atye; Adib-Hajbaghery, Mohsen

2014-08-01

Sleep disorders are common among patients hospitalized in coronary care unit (CCU). This study aimed to investigate the effect of Rosa damascene aromatherapy on sleep quality of patients hospitalized in CCU. In this randomized controlled trial, 60 patients who met the inclusion criteria were conveniently sampled and randomly allocated to the experimental and control groups. Patients in the control group received routine care. In the experimental group, patients received routine care and Rosa damascene aromatherapy for three subsequent nights. In the both groups the sleep quality was assessed using the Pittsburgh Sleep Quality Index. After the study, the mean scores of five domains of Pittsburg Sleep Quality Index as well as the mean of total score of the index in the experimental group were significantly lower than the control group. Rosa damascene aromatherapy can significantly improve the sleep quality of patients hospitalized in CCUs. Copyright © 2014 Elsevier Ltd. All rights reserved.
Electromigration-induced plasticity and texture in Cu interconnects

International Nuclear Information System (INIS)

Advanced Light Source; Tamura, Nobumichi; Budiman, A. S.; Hau-Riege, C.S.; Besser, P. R.; Marathe, A.; Joo, Y.-C.; Tamura, N.; Patel, J. R.; Nix, W. D.

2007-01-01

Plastic deformation has been observed in damascene Cu interconnect test structures during an in-situ electromigration experiment and before the onset of visible microstructural damage (ie. voiding) using a synchrotron technique of white beam X-ray microdiffraction. We show here that the extent of this electromigration-induced plasticity is dependent on the texture of the Cu grains in the line. In lines with strong textures, the extent of plastic deformation is found to be relatively large compared to our plasticity results in the previous study [1] using another set of Cu lines with weaker textures. This is consistent with our earlier observation that the occurrence of plastic deformation in a given grain can be strongly correlated with the availability of a direction of the crystal in the proximity of the direction of the electron flow in the line (within an angle of 10 o ). In out-of-plane oriented grains in a damascene interconnect scheme, the crystal plane facing the sidewall tends to be a {110} plane,[2-4] so as to minimize interfacial energy. Therefore, it is deterministic rather than probabilistic that the grains will have a direction nearly parallel to the direction of electron flow. Thus, strong textures lead to more plasticity, as we observe
Electromigration-induced Plasticity and Texture in Cu Interconnects

Science.gov (United States)

Budiman, A. S.; Hau-Riege, C. S.; Besser, P. R.; Marathe, A.; Joo, Y.-C.; Tamura, N.; Patel, J. R.; Nix, W. D.

2007-10-01

Plastic deformation has been observed in damascene Cu interconnect test structures during an in-situ electromigration experiment and before the onset of visible microstructural damage (ie. voiding) using a synchrotron technique of white beam X-ray microdiffraction. We show here that the extent of this electromigration-induced plasticity is dependent on the texture of the Cu grains in the line. In lines with strong textures, the extent of plastic deformation is found to be relatively large compared to our plasticity results in the previous study[1] using another set of Cu lines with weaker textures. This is consistent with our earlier observation that the occurrence of plastic deformation in a given grain can be strongly correlated with the availability of a direction of the crystal in the proximity of the direction of the electron flow in the line (within an angle of 10°). In out-of-plane oriented grains in a damascene interconnect scheme, the crystal plane facing the sidewall tends to be a {110} plane,[2-4] so as to minimize interfacial energy. Therefore, it is deterministic rather than probabilistic that the grains will have a direction nearly parallel to the direction of electron flow. Thus, strong textures lead to more plasticity, as we observe.
Electromigration-induced plasticity and texture in Cu interconnects

Energy Technology Data Exchange (ETDEWEB)

Advanced Light Source; Tamura, Nobumichi; Budiman, A. S.; Hau-Riege, C.S.; Besser, P. R.; Marathe, A.; Joo, Y.-C.; Tamura, N.; Patel, J. R.; Nix, W. D.

2007-10-31

Plastic deformation has been observed in damascene Cu interconnect test structures during an in-situ electromigration experiment and before the onset of visible microstructural damage (ie. voiding) using a synchrotron technique of white beam X-ray microdiffraction. We show here that the extent of this electromigration-induced plasticity is dependent on the texture of the Cu grains in the line. In lines with strong <111> textures, the extent of plastic deformation is found to be relatively large compared to our plasticity results in the previous study [1] using another set of Cu lines with weaker textures. This is consistent with our earlier observation that the occurrence of plastic deformation in a given grain can be strongly correlated with the availability of a <112> direction of the crystal in the proximity of the direction of the electron flow in the line (within an angle of 10{sup o}). In <111> out-of-plane oriented grains in a damascene interconnect scheme, the crystal plane facing the sidewall tends to be a {l_brace}110{r_brace} plane,[2-4] so as to minimize interfacial energy. Therefore, it is deterministic rather than probabilistic that the <111> grains will have a <112> direction nearly parallel to the direction of electron flow. Thus, strong <111> textures lead to more plasticity, as we observe.
Study on the Effects of Corrosion Inhibitor According to the Functional Groups for Cu Chemical Mechanical Polishing in Neutral Environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Won; Kim, Jae Jeong [Institute of Chemical Process, Seoul National University, Seoul (Korea, Republic of)

2015-08-15

As the aluminum (Al) metallization process was replaced with copper (Cu), the damascene process was introduced, which required the planarization step to eliminate over-deposited Cu with Chemical Mechanical Polishing (CMP) process. In this study, the verification of the corrosion inhibitors, one of the Cu CMP slurry components, was conducted to find out the tendency regarding the carboxyl and amino functional group in neutral environment. Through the results of etch rate, removal rate, and chemical ability of corrosion inhibitors based on 1H-1,2,4-triazole as the base corrosion inhibitor, while the amine functional group presents high Cu etching ability, carboxyl functional group shows lower Cu etching ability than base-corrosion inhibitor which means that it increases passivation effect by making strong passivation layer. It implies that the corrosion inhibitor with amine functional group was proper to apply for 1st Cu CMP slurry owing to the high etch rate and with carboxyl functional group was favorable for the 2nd Cu CMP slurry due to the high Cu removal rate/dissolution rate ratio.
MFM observation of spin structures in nano-magnetic-dot arrays fabricated by damascene technique

International Nuclear Information System (INIS)

Sato, K.; Yamamoto, T.; Tezuka, T.; Ishibashi, T.; Morishita, Y.; Koukitu, A.; Machida, K.; Yamaoka, T.

2006-01-01

Regularly aligned arrays of magnetic nano dots buried in silicon wafers have been fabricated using damascene technique with the help of electron beam lithography. Arrays of square, rectangular, cross-shaped and Y-shaped structures of submicron size have been obtained. Spin distributions have been observed by means of magnetic force microscopy and analyzed by a micromagnetic simulation with Landau-Lifshitz-Gilbert equations. Importance of magnetostatic interactions working between adjacent dots has been elucidated
Aromatherapy with Rosa Damascenes in Apnea, Bradycardia and Spo2 of Preterm Infants; a Randomized Clinical Trial

Directory of Open Access Journals (Sweden)

Saeideh Aghagoli

2016-06-01

Full Text Available Background Apnea is one of the most common problems in preterm neonates. This study aimed to evaluate the effectiveness of aromatherapy on the reduction of apnea, bradycardia, and Pulse Oximetry (SPO2 in premature infants. Materials and Methods In a clinical trial study, 60 preterm neonates randomly divided in two groups and exposed to aromatherapy with Rosa damascenes distillate or distilled water beside the routine treatment. In experimental group, two drops of 10% Rosa damascenes distillate was dropped on the pad eye in second day of birth at 6 Am. The intervention was repeated in 9 AM, 12 Am, 15 PM and 18 PM hours. A same condition applied for control group and distilled water was dropped on the pad eye. The number of apnea attacks, bradycardia and decrease in SpO2 compared between two groups using chi-square test, independent t-test and repeated measure test. Results The overall apnea attacks, bradycardia, and SPO2 in tree studied days were lower in intervention group than control group (0.47±0.13 vs. 2.6±0.41, 0.47±0.13 vs. 2.56±0.41 and 0.70±0.17 vs. 2.77±0.21, respectively. In addition, the repeated measurement test showed that the mean number of apnea attacks, decrease in heart pulse rate, and decrease in SpO2 was statistically lower in intervention group with aromatherapy than controls in first, second, third and sum of three days (P< 0.05. Conclusion Aromatherapy with Rosa damascenes distillate can reduce more and speedy the occurrence of apnea attacks, bradycardia and SPO2 in premature infants, along with other routine treatment.
PROPORTIONS AND HUMAN SCALE IN DAMASCENE COURTYARD HOUSES

Directory of Open Access Journals (Sweden)

M. Salim Ferwati

2008-03-01

Full Text Available Interior designers, architects, landscape architects, and even urban designers, agree that environment, as a form of non-verbal communication means, has a symbolic dimension to it. As for its aesthetic dimension, it seems that beauty is related to a certain proportion, partially and as a whole. Suitable proportion leaves a good impression upon the beholders, especially when it matches human proportion. That in fact was the underlining belief of LeCorbusier, according to which he developed his Modular concept. The study searches for a modular, or proportion, system that governs the design of Damascene traditional house. By geometrical and mathematical examinations of 28 traditional houses, it was found that a certain proportional relationship existed; however, these proportional relationships were not fixed ones. The study relied on analyzing the Iwan elevation as well as the inner courtyard proportion in relation to the building area. Charts, diagrams and tables were produced to summarize the results.
Microstructure, impurity and metal cap effects on Cu electromigration

Energy Technology Data Exchange (ETDEWEB)

Hu, C.-K.; Gignac, L. G.; Ohm, J.; Breslin, C. M.; Huang, E.; Bonilla, G.; Liniger, E.; Rosenberg, R. [IBM T. J. Watson Research Center, Yorktown Heights, NY 10598 (United States); Choi, S.; Simon, A. H. [IBM Microelectronic Division, Hopewell Junction, NY 12533 (United States)

2014-06-19

Electromigration (EM) lifetimes and void growth of pure Cu, Cu(Mn) alloy, and pure Cu damascene lines with a CoWP cap were measured as a function of grain structure (bamboo, near bamboo, and polycrystalline) and sample temperature. The bamboo grains in a bamboo-polycrystalline grained line play the key role in reducing Cu mass flow. The variation in Cu grain size distribution among the wafers was achieved by varying the metal line height and wafer annealing process step after electroplating Cu and before or after chemical mechanical polishing. The Cu grain size was found to have a large impact on Cu EM lifetime and activation energy, especially for the lines capped with CoWP. The EM activation energy for pure Cu with a CoWP cap from near-bamboo, bamboo-polycrystalline, mostly polycrystalline to polycrystalline only line grain structures was reduced from 2.2 ± 0.2 eV, to 1.7 ± 0.1 eV, to 1.5 ± 0.1 eV, to 0.72 ± 0.05 eV, respectively. The effect of Mn in Cu grain boundary diffusion was found to be dependent on Mn concentration in Cu. The depletion of Cu at the cathode end of the Cu(Mn) line is preceded by an incubation period. Unlike pure Cu lines with void growth at the cathode end and hillocks at the anode end of the line, the hillocks grew at a starting position roughly equal to the Blech critical length from the cathode end of the Cu(Mn) polycrystalline line. The effectiveness of Mn on Cu grain boundary migration can also be qualitatively accounted for by a simple trapping model. The free migration of Cu atoms at grain boundaries is reduced by the presence of Mn due to Cu-solute binding. A large binding energy of 0.5 ± 0.1 eV was observed.
Via fill properties of organic BARCs in dual-damascene application

Science.gov (United States)

Huang, Runhui

2004-05-01

With the introduction of copper as the interconnect metal, the Dual Damascene (DD) process has been integrated into integrated circuit (IC) device fabrication. The DD process utilizes organic bottom anti-reflective coatings (BARCs) not only to eliminate the thin film interference effects but also to act as via fill materials. However, three serious processing problems are encountered with organic BARCs. One is the formation of voids, which are trapped gas bubbles (evaporating solvent, byproduct of the curing reaction and air) inside the vias. Another problem is non-uniform BARC layer thickness in different via pitch areas. The third problem is the formation of fences during plasma etch. Fences are formed from materials that are removed by plasma and subsequently deposited on the sidewall surrounding the via openings during the etching process. Voids can cause variations in BARC top thickness, optical properties, via fill percentage, and plasma etch rate. This study focuses on the factors that influence the formation of voids and addresses the ways to eliminate them by optimizing the compositions of formulations and the processing conditions. Effects of molecular weight of the polymer, nature of the crosslinker, additives, and bake temperature were examined. The molecular weight of the polymer is one of the important factors that needs to be controlled carefully. Polymers with high molecular weights tend to trap voids inside the vias. Low molecular weight polymers have low Tg and low viscosity, which enables good thermal flow so that the BARC can fill vias easily without voids. Several kinds of crosslinkers were investigated in this study. When used with the same polymer system, formulations with different crosslinkers show varying results that affect planar fill, sidewall coverage, and, in some cases, voids. Additives also can change via fill behavior dramatically, and choosing the right additive will improve the via fill property. Processing conditions such as
Optimized ultra-thin manganin alloy passivated fine-pitch damascene compatible bump-less Cu-Cu bonding at sub 200 °C for three-dimensional Integration applications

Science.gov (United States)

Panigrahi, Asisa Kumar; Hemanth Kumar, C.; Bonam, Satish; Ghosh, Tamal; Rama Krishna Vanjari, Siva; Govind Singh, Shiv

2018-02-01

Enhanced Cu diffusion, Cu surface passivation, and smooth surface at the bonding interface are the key essentials for high quality Cu-Cu bonding. Previously, we have demonstrated optimized 3 nm thin Manganin metal-alloy passivation from oxidation and also helps to reduce the surface roughness to about 0.8 nm which substantially led to high quality Cu-Cu bonding. In this paper, we demonstrated an ultra fine-pitch (indication of high quality bonding for future multilayer integrations. Furthermore, electrical characterization of the bonded structure was performed under various robust conditions as per International Technology Roadmap for Semiconductors (ITRS Roadmap) in order to satisfy the stability of the bonded structure.
In-situ EC-STM studies on the influence of halide anions on structure and reactivity of dibenzylviologen on Cu(100)

Energy Technology Data Exchange (ETDEWEB)

Gentz, Knud; Wandelt, Klaus [Institute of Physical and Theoretical Chemistry, Bonn University (Germany); Broekmann, Peter [University of Bern (Switzerland)

2009-07-01

Copper has become a focus of research activities over the last two decades due to its use as interconnect material in microchip design. Nitrogen-containing cationic organic molecules have been studied as additives for the so-called copper damascene process. In the present investigation the structures and reactivity of a dibenzylviologen (DBV) layer adsorbed on a bromide-modified Cu(100) surface have been studied by in-situ electrochemical STM and will be compared to the results on the chloride-modified substrate and the related Diphenylviologen (DPV). N,N'-dibenzyl-4,4'-bipyridinium molecules (dibenzylviologen, DBV) spontaneously adsorb on a halide-modified Cu(100)-surface, forming distinctive patterns, which have been characterized by in-situ scanning tunneling microscopy. Depending on the adsorption potential a striped phase, a cavitand phase and an amorphous phase have been identified. Cyclic voltammetry indicates that even more processes take place on the surface, because if the potential is decreased beyond a range of fully reversible processes, an irreversible surface phase formation is observed at -450 mV vs. RHE. This surface phase passivates the surface against adsorption of the dicationic phase, so the charge reversal of the interface in the outer Helmholtz layer seems to be reduced.
Processing of R-Ba-Cu-O superconductors

International Nuclear Information System (INIS)

Wu, H.

1998-01-01

Precipitation processes were developed to introduce second phases as flux pinning centers in Gd-Ba-Cu-O and Nd-Ba-Cu-O superconductors. In Gd-Ba-Cu-O, precipitation is caused by the decrease of the upper solubility limit of Gd 1+x Ba 2-x Cu 3 O 7 solid solution (Gd123ss) in low oxygen partial pressure. Processing of supersaturated Gd 1.2 Ba 1.8 Cu 3 O 7 in low oxygen partial pressure can produce dispersed second phases. Gd211 is formed as a separate phase while extensive Gd124 type stacking fault is formed instead of a separate CuO phase. As a result of the precipitation reaction, the transition temperature and critical current density are increased. In Nd-Ba-Cu-O, precipitation is caused by the decrease of the lower solubility limit of Nd 1+x Ba 2-x Cu 3 O 7 solid solution (Nd123ss) in oxygen. DTA results reveal the relative stability of Nd123ss in different oxygen partial pressures. In 1 bar oxygen partial pressure, Nd123ss with x = 0.1 is the most stable phase. In lower oxygen partial pressures, the most stable composition shifts towards the stoichiometric composition. The relative stability changes faster with decreasing oxygen partial pressure. Therefore, processing in oxygen and air tends to produce broad superconducting transitions but sharp transitions can be achieved in 0.01 bar and 0.001 bar oxygen partial pressures. While the lower solubility limits in 0.01 bar and 0.001 bar oxygen partial pressures remain at x = 0.00, the solubility limits in oxygen and air show a narrowing with decreasing temperature. Because of the narrowing of the solubility range in oxygen, oxygen annealing of Nd123 initially processed in low oxygen partial pressures will result in precipitation of second phases. The equilibrium second phase is BaCuO 2 for temperature above 608 C, and at lower temperatures the equilibrium second phases are Ba 2 CuO 3.3 and Ba 2 Cu 3 O 5+y . However, annealing at low temperature may produce a fine metastable transition phase. A coherent intermediate

ECAE-processed Cu-Nb and Cu-Ag nanocomposite wires for pulse magnet applications

International Nuclear Information System (INIS)

Edgecumbe Summers, T.S.; Walsh, R.P.; Pernambuco-Wise, P.

1997-01-01

Cu-Nb and Cu-Ag nanocomposites have recently become of interest to pulse magnet designers because of their unusual combination of high strength with reasonable conductivity. In the as-cast condition, these conductors consist of two phases, one of almost pure Nb (or Ag) and the other almost pure Cu. When these castings are cold worked as in a wire-drawing operation for example, the two phases are drawn into very fine filaments which produce considerable strengthening without an unacceptable decrease in conductivity. Unfortunately, any increase in strength with operations such as wire drawing is accompanied by a reduction in the cross section of the billet, and thus far, no wires with strengths on the order of 1.5 GPa or more have been produced with cross sections large enough to be useful in magnet applications. Equal Channel Angular Extrusion (ECAE) is an innovative technique which allows for the refinement of the as-cast ingot structure without a reduction in the cross sectional dimensions. Samples processed by the ECAE technique prior to wire drawing should be stronger at a given wire diameter than those processed by wire drawing alone. The tensile properties of wire-drawn Cu-18%Nb and Cu-25%Ag both with and without prior ECAE processing were tested and compared at both room temperature and 77K. All samples were found to have resistivities consistent with their strengths, and the strengths of the ECAE-processed wires were significantly higher than their as-cast and drawn counterparts. Therefore, with ECAE processing prior to wire drawing, it appears to be possible to make high-strength conductors with adequately large cross sections for pulse magnets
Cytotoxic and genotoxic studies of essential oil from Rosa damascene Mill., Kashan, Iran.

Science.gov (United States)

Shokrzadeh, Mohammad; Habibi, Emran; Modanloo, Mona

2017-08-01

Aim Rosa damascene Mill. belongs to the family of Roseaceae and its essential oil is produced in large amounts in Iran. The wide application of rose oil has raised questions about potential adverse health effects. We have investigated cytotoxic activity and genotoxic effects of Rosa oil from Kashan, Iran. Methods The cytotoxic effect and IC50 of the essential oil on the cell lines was studied followed by MTT assay. In this assay mitochondrial oxidoreductase enzymes with reducing the tetrazolium dye MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) reflect the number of viable cells. Genotoxic effect of the oil was evaluated by micronucleus assay by evaluating produced micronuclei due to cytogenetic damage in binucleated lymphocytes. Results The results showed that essential oil significantly had cytotoxic and genotoxic effects at doses over 10µg/mL (pessential oil of Rose showed lower IC50 in cancer cell line (A549) in comparison with the normal cell line (NIH3T3). Conclusion Cytotoxic and genotoxic properties of essential oil of Rose in Kashan, Iran, are safe at a dose of 10µg/mL. Also, a good cytotoxic effect was shown and could be introduced as an anticancer compound. Further studies are needed with regard to anti-cancer effects of Rose essential oil. Copyright© by the Medical Assotiation of Zenica-Doboj Canton.
Simple solution-processed CuOX as anode buffer layer for efficient organic solar cells

International Nuclear Information System (INIS)

Shen, Wenfei; Yang, Chunpeng; Bao, Xichang; Sun, Liang; Wang, Ning; Tang, Jianguo; Chen, Weichao; Yang, Renqiang

2015-01-01

Graphical abstract: - Highlights: • Simple solution-processed CuO X hole transport layer for efficient organic solar cell. • Good photovoltaic performances as hole transport layer in OSCs with P3HT and PBDTTT-C as donor materials. • The device with CuO X as hole transport layer shows great improved stability compared with that of device with PEDOT:PSS as hole transport layer. - Abstract: A simple, solution-processed ultrathin CuO X anode buffer layer was fabricated for high performance organic solar cells (OSCs). XPS measurement demonstrated that the CuO X was the composite of CuO and Cu 2 O. The CuO X modified ITO glass exhibit a better surface contact with the active layer. The photovoltaic performance of the devices with CuO X layer was optimized by varying the thickness of CuO X films through changing solution concentration. With P3HT:PC 61 BM as the active layer, we demonstrated an enhanced PCE of 4.14% with CuO X anode buffer layer, compared with that of PEDOT:PSS layer. The CuO X layer also exhibits efficient photovoltaic performance in devices with PBDTTT-C:PC 71 BM as the active layer. The long-term stability of CuO X device is better than that of PEDOT:PSS device. The results indicate that the easy solution-processed CuO X film can act as an efficient anode buffer layer for high-efficiency OSCs
The influence of precursor Cu content and two-stage processing conditions on the microstructure of Cu{sub 2}ZnSnSe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Márquez-Prieto, J., E-mail: jose.prieto@northumbria.ac.uk [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom); Ren, Y. [Ångström Solar Center, Solid State Electronics, Uppsala University, Uppsala 751 21 (Sweden); Miles, R.W.; Pearsall, N.; Forbes, I. [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom)

2015-05-01

This paper reports the influence of processing temperature on the microstructure of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) absorber layers for temperatures between 380 and 550 °C produced using a 2-stage process. X-ray diffraction analysis showed the formation of Cu{sub 2}ZnSnSe{sub 4} over this temperatures range. The Williamson-Hall method was used for microstructural analysis of the CZTSe absorbers, and this showed a progressive decrease of the micro-strain of the CZTSe with increasing selenisation temperature. The influence of precursor Cu content on the microstructure of the CZTSe was also studied. An increase of Cu content in the precursor is correlated to an increase in grain size and a decrease in micro-strain. Raman measurements show an asymmetrical broadening towards lower energies of the main 197 cm{sup −1} mode for Cu-poor compositions. This study provides an insight into the dependency of the crystallinity of CZTSe on composition and synthesis temperature. - Highlights: • We fabricate Cu{sub 2}ZnSnSe{sub 4} thin films by sputtering and post-reactive annealing. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} decreases with increasing processing temperature. • The defect concentration of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases.
Effects of processing parameters on Be/CuCrZr joining

International Nuclear Information System (INIS)

Park, Jeong-Yong; Lee, Jung-Suk; Choi, Byung-Kwon; Park, Sang-Yun; Hong, Bong Guen; Jeong, Yong Hwan; Jung, Ki-Jung

2007-01-01

A joining of Be/CuCrZr has been considered as the key technology for the fabrication of the ITER first wall. Among the joining methods, Hot isostatic pressing (HIP), which is one of the diffusion bonding methods, is the most feasible method to join the Be and CuCrZr alloy. In the HIP joining of Be and CuCrZr, the interlayer was used to prevent the formation of brittle intermetallic compounds in the interface. Therefore, it is crucial to select a suitable interlayer for a joining of Be and CuCrZr. On the other hand, the diffusion between Be and CuCrZr would be enhanced with an increase of the HIP joining temperature, thereby increasing the joint strength. However, the HIP joining temperature is limited by the mechanical properties of CuCrZr. During the fabrication process of the ITER first wall, CuCrZr is subjected to several thermal cycles including a solution annealing, a cooling and an aging. The HIP joining of Be and CuCrZr corresponds to the aging of CuCrZr. The HIP joining at a higher temperature would cause a degradation of the mechanical properties of CuCrZr by an overaging effect although it is preferable for an improvement of the joint strength. In this study, the effect of the cooling rate on the mechanical properties of aged CuCrZr was investigated to find the maximum HIP temperature without a degradation of the mechanical properties of CuCrZr
Infrared processed Cu composites reinforced with WC particles

International Nuclear Information System (INIS)

Deshpande, P.K.; Li, J.H.; Lin, R.Y.

2006-01-01

Copper matrix composites with WC particle reinforcements have been prepared with an innovative infrared infiltration technique. The volume content of the reinforcement particles in the composite is about 53%. The relative composite density of as high as 99.9% has been obtained with this process. The electric conductivity of composites prepared in this study as determined by a four-point probe method, is similar to commercially available Cu/W composites containing 52 vol% tungsten. Microhardness, microstructure and wear resistance of the composites were also determined. The microstructure of Cu/WC composite reveals excellent wetting between the two constituent phases, WC and copper. The microhardness values of all completely infiltrated Cu/WC composites were in the range of 360-370 HV which is significantly higher than the microhardness of pure copper, 65 HV. Wear resistance of the composites was determined with a pin on disk wear test technique. The wear test results show that composites prepared in this study performed much better than those commercially available Cu/W composites by more than two-fold against silicon carbide abrasive disks
Melt-spin processing of YBa2Cu3O7-x

International Nuclear Information System (INIS)

Folkerts, T.J.; Kramer, M.J.; McCallum, R.W.; Iowa State Univ. of Science and Technology, Ames, IA

1991-01-01

We introduce a novel containerless melt-spin processing technique for YBa 2 Cu 3 O 7-x using prereacted oxide powders which are rapidly melted and subsequentially quenched in a controlled atmosphere. This results in flakes with typical dimensions of 3000x150x15 μm 3 . Powder XRD indicates that all samples contain Y 2 O 3 , but that the Ba--Cu--O phases present depend on the processing parameters. SEM and TEM studies show these phases are finely dispersed: the typical grain size for Y 2 O 3 is 1--2 μm, and for the Ba--Cu--O phases it is <0.5 μm
Direct, CMOS In-Line Process Flow Compatible, Sub 100 °C Cu-Cu Thermocompression Bonding Using Stress Engineering

Science.gov (United States)

Panigrahi, Asisa Kumar; Ghosh, Tamal; Kumar, C. Hemanth; Singh, Shiv Govind; Vanjari, Siva Rama Krishna

2018-03-01

Diffusion of atoms across the boundary between two bonding layers is the key for achieving excellent thermocompression Wafer on Wafer bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu-Cu bonding which is devoid of Cu surface treatment prior to bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality thermocompression bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10-8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu-Cu bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu-Cu bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable bonding without electrical performance degradation.
Direct, CMOS In-Line Process Flow Compatible, Sub 100 °C Cu-Cu Thermocompression Bonding Using Stress Engineering

Science.gov (United States)

Panigrahi, Asisa Kumar; Ghosh, Tamal; Kumar, C. Hemanth; Singh, Shiv Govind; Vanjari, Siva Rama Krishna

2018-05-01

Diffusion of atoms across the boundary between two bonding layers is the key for achieving excellent thermocompression Wafer on Wafer bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu-Cu bonding which is devoid of Cu surface treatment prior to bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality thermocompression bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10-8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu-Cu bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu-Cu bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable bonding without electrical performance degradation.
Homogeneous (Cu, Ni)6Sn5 intermetallic compound joints rapidly formed in asymmetrical Ni/Sn/Cu system using ultrasound-induced transient liquid phase soldering process.

Science.gov (United States)

Li, Z L; Dong, H J; Song, X G; Zhao, H Y; Tian, H; Liu, J H; Feng, J C; Yan, J C

2018-04-01

Homogeneous (Cu, Ni) 6 Sn 5 intermetallic compound (IMC) joints were rapidly formed in asymmetrical Ni/Sn/Cu system by an ultrasound-induced transient liquid phase (TLP) soldering process. In the traditional TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system consisted of major (Cu, Ni) 6 Sn 5 and minor Cu 3 Sn IMCs, and the grain morphology of (Cu, Ni) 6 Sn 5 IMCs subsequently exhibited fine rounded, needlelike and coarse rounded shapes from the Ni side to the Cu side, which was highly in accordance with the Ni concentration gradient across the joints. However, in the ultrasound-induced TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system only consisted of the (Cu, Ni) 6 Sn 5 IMCs which exhibited an uniform grain morphology of rounded shape with a remarkably narrowed Ni concentration gradient. The ultrasound-induced homogeneous intermetallic joints exhibited higher shear strength (61.6 MPa) than the traditional heterogeneous intermetallic joints (49.8 MPa). Copyright © 2017 Elsevier B.V. All rights reserved.
Treatment of reverse osmosis (RO) concentrate by the combined Fe/Cu/air and Fenton process (1stFe/Cu/air-Fenton-2ndFe/Cu/air).

Science.gov (United States)

Ren, Yi; Yuan, Yue; Lai, Bo; Zhou, Yuexi; Wang, Juling

2016-01-25

To decompose or transform the toxic and refractory reverse osmosis (RO) concentrate and improve the biodegradability, 1stFe/Cu/air-Fenton-2ndFe/Cu/air were developed to treat RO concentrate obtained from an amino acid production plant in northern China. First, their operating conditions were optimized thoroughly. Furthermore, 5 control experiments were setup to confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and synergistic reaction between Fe/Cu/air and Fenton. The results suggest that the developed method could obtain high COD removal (65.1%) and BOD5/COD ratio (0.26) due to the synergistic reaction between Fe/Cu/air and Fenton. Under the optimal conditions, the influent and effluent of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and 5 control experiments were analyzed by using UV, FTIR, EEM and LC, which confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air. Therefore, the developed method in this study is a promising process for treatment of RO concentrate. Copyright © 2015 Elsevier B.V. All rights reserved.
Ultrafine grained Cu processed by compression with oscillatory torsion

OpenAIRE

K. Rodak

2007-01-01

Purpose: The aim of this work is a study of Cu microstructure after severe plastic deformation process by usingcompression with oscillatory torsion test.Design/methodology/approach: Cu samples were deformed at torsion frequency (f) changed from 0 Hz(compression) to 1.8 Hz under a constant torsion angle (α) ≈8° and compression speed (v)=0.1mm/s. Structuralinvestigations were conducted by using light microscopy (LM) and transmission electron microscopy (TEM).Findings: The structural analysis ma...
Processing and characterization of composite CuO/CuO/Cu-CGO obtained by a chemical synthesis route in one step

International Nuclear Information System (INIS)

Sousa, A.R.O. de; Menezes, A.J.; Souza, G.S.; Lima, C.G.M. de; Souza, G.S.; Dutra, R.P.S.; Macedo, D.A.

2016-01-01

This paper deals with the processing and characterization of composite CuO / ceria doped with 10 mol% gadolinia (CuO-Ce0,9Gd0,1O1,95) obtained by a chemical synthesis route in one step. It was varied CuO content at 40, 50 and 60% by weight, resulting in resin precursor, which was mixed with the CGO and then heat treated at 350 ° C and subsequently calcined at 1050 deg C. The particulate materials were characterized by X-ray diffractometry using powders, it was possible to synthesize and deposit, by serigraphy, films of the anodes of the three compositions CGO electrolyte. The technique of impedance spectroscopy allowed the analysis of the electrical properties of the material, as well as the understanding of their behavior when subjected to different atmospheres of hydrogen and methane. (author)
Efficient Destruction of Pollutants in Water by a Dual-Reaction-Center Fenton-like Process over Carbon Nitride Compounds-Complexed Cu(II)-CuAlO2.

Science.gov (United States)

Lyu, Lai; Yan, Dengbiao; Yu, Guangfei; Cao, Wenrui; Hu, Chun

2018-04-03

Carbon nitride compounds (CN) complexed with the in-situ-produced Cu(II) on the surface of CuAlO 2 substrate (CN-Cu(II)-CuAlO 2 ) is prepared via a surface growth process for the first time and exhibits exceptionally high activity and efficiency for the degradation of the refractory pollutants in water through a Fenton-like process in a wide pH range. The reaction rate for bisphenol A removal is ∼25 times higher than that of the CuAlO 2 . According to the characterization, Cu(II) generation on the surface of CuAlO 2 during the surface growth process results in the marked decrease of the surface oxygen vacancies and the formation of the C-O-Cu bridges between CN and Cu(II)-CuAlO 2 in the catalyst. The electron paramagnetic resonance (EPR) analysis and density functional theory (DFT) calculations demonstrate that the dual reaction centers are produced around the Cu and C sites due to the cation-π interactions through the C-O-Cu bridges in CN-Cu(II)-CuAlO 2 . During the Fenton-like reactions, the electron-rich center around Cu is responsible for the efficient reduction of H 2 O 2 to • OH, and the electron-poor center around C captures electrons from H 2 O 2 or pollutants and diverts them to the electron-rich area via the C-O-Cu bridge. Thus, the catalyst exhibits excellent catalytic performance for the refractory pollutant degradation. This study can deepen our understanding on the enhanced Fenton reactivity for water purification through functionalizing with organic solid-phase ligands on the catalyst surface.
Theories of transporting processes of Cu in Jiaozhou Bay

Science.gov (United States)

Yang, Dongfang; Su, Chunhua; Zhu, Sixi; Wu, Yunjie; Zhou, Wei

2018-02-01

Many marine bays have been polluted along with the rapid development of industry and population size, and understanding the transporting progresses of pollutants is essential to pollution control. In order to better understanding the transporting progresses of pollutants in marine, this paper carried on a comprehensive research of the theories of transporting processes of Cu in Jiaozhou Bay. Results showed that the transporting processes of Cu in this bay could be summarized into seven key theories including homogeneous theory, environmental dynamic theory, horizontal loss theory, source to waters transporting theory, sedimentation transporting theory, migration trend theory and vertical transporting theory, respectively. These theories helpful to better understand the migration progress of pollutants in marine bay.
Category Cued Recall Evokes a Generate-Recognize Retrieval Process

Science.gov (United States)

Hunt, R. Reed; Smith, Rebekah E.; Toth, Jeffrey P.

2016-01-01

The experiments reported here were designed to replicate and extend McCabe, Roediger, and Karpicke's (2011) finding that retrieval in category cued recall involves both controlled and automatic processes. The extension entailed identifying whether distinctive encoding affected 1 or both of these 2 processes. The first experiment successfully…
Effect of annealing process on the heterostructure CuO/Cu2O as a highly efficient photocathode for photoelectrochemical water reduction

Science.gov (United States)

Du, Fan; Chen, Qing-Yun; Wang, Yun-Hai

2017-05-01

CuO/Cu2O photocathodes were successfully prepared via simply annealing the electrodeposited Cu2O on fluoride doped tin oxide (FTO) substrate. They were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-vis absorption spectra and X-ray photoelectron spectroscopy (XPS). The results showed that the heterojunction of CuO/Cu2O was formed during the annealing process and presented the nature of p-type semiconductor. The photocurrent density and photoelectrochemical (PEC) stability of the p-type heterostructure CuO/Cu2O photocathode was improved greatly compared with the pure Cu2O, which was greatly affected by annealing time and temperature. The highest photo current density of -0.451 mA/cm2 and highest stability was obtained via annealing at 650 °C for 15 min (at -0.3 V vs. Ag/AgCl), which gave a remarkable improvement than the as-deposited Cu2O (-0.08 mA/cm2). This suggested that the CuO/Cu2O heterojunction facilitated the electron-hole pair separation and improved the photocathode's current and stability.
Adsorption Behavior of TBPS in the Process of Cu Electrodeposition on an Au Film.

Science.gov (United States)

Chen, Liang-Huei; Liu, Yung-Fang; Krug, Klaus; Lee, Yuh-Lang

2018-05-15

The adsorption behavior of an Cu electroplating additive, 3,3 thiobis-(1-propanesulfonic acid sodium salt) (TBPS) in a process of Cu deposition onto a single crystalline Au(111) surface is studied by an in-situ Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS). The SEIRAS spectra of the TBPS adlayer on a Cu film is investigated first and compared to that on an Au film. These results are utilized to evaluate the characteristics of TBPS adlayer on the electrode surface during the Cu deposition and stripping processes. The results show that the SEIRAS spectra of TBPS adsorbed on the Cu film resembles closely to that on the Au film, and the most pronounced peaks are symmetric S-O (ss-SO) and asymmetric S-O (as-SO) stretching modes. However, the as-SO band is sharper with a higher intensity on the Cu film. Since the ss-SO and as-SO peaks correspond to the molecular with upright and lie-down orientations, respectively, it implies that the TBPS molecules have higher ratio of lie-down orientation on the Cu film. In the Cu electrodeposition process, the cyclic voltammetry (CV) result shows that the presence of the TBPS in the HClO 4 solution can decrease the inhibition effect of HClO 4 to the Cu deposition. For the spectra measured at various potential during cathodic and anodic sweeping, an obvious change of the spectra occurs at ca. 0.6 V, the initiation of Cu underpotential deposition (Cu-UPD). For potentials higher and lower than 0.6 V, the spectra are similar, respectively, to those measured for the Au and Cu films. This result indicates that the TBPS molecules originally adsorbing on the Au film transfer to the surface of deposited Cu layer. This inference is also confirmed by the variation in wavenumber and peak intensity of ss-SO and as-SO peaks during the potential sweeping.
Evolution process of the synthesis of TiC in the Cu-Ti-C system

International Nuclear Information System (INIS)

Liang, Y.H.; Wang, H.Y.; Yang, Y.F.; Wang, Y.Y.; Jiang, Q.C.

2008-01-01

The evolution process of TiC formation in the 20 wt.% Cu-Ti-C powder mixtures was studied by using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Ti x Cu y compounds (Ti 2 Cu, TiCu, Ti 3 Cu 4 and TiCu 4 ) formed initially via solid-state diffusion reactions between Cu and Ti particles; and then Ti 2 Cu and TiCu can form a Cu-Ti eutectic liquids at about 1233 K. The unreacted Ti and C particles dissolved into the Cu-Ti liquids and led to the formation of Cu-Ti-C ternary liquids; subsequently, TiC particulates precipitated out of the saturated liquids. At the same time, also the formation of Ti 2 Cu occurred at the interface between the Cu-Ti liquids and the unreacted Ti particles. As the temperature increased further, the Ti 2 Cu melted and more Cu-Ti liquids formed; and then C particles continuously dissolved into the Cu-Ti-C liquids and TiC particulates gradually precipitated out of the saturated liquids
Production and processing of Cu-Cr-Nb alloys

International Nuclear Information System (INIS)

Ellis, D.L.; Michal, G.M.; Orth, N.W.

1990-01-01

A new Cu-based alloy possessing high strength, high conductivity, and good stability at elevated temperatures was recently produced. This paper details the melting of the master alloys, production of rapidly solidified ribbon, and processing of the ribbon to sheet by hot pressing and hot rolling

Production and processing of Cu-Cr-Nb alloys

Science.gov (United States)

Ellis, David L.; Michal, Gary M.; Orth, Norman W.

1990-01-01

A new Cu-based alloy possessing high strength, high conductivity, and good stability at elevated temperatures was recently produced. This paper details the melting of the master alloys, production of rapidly solidified ribbon, and processing of the ribbon to sheet by hot pressing and hot rolling.
Influence of Y2BaCuO5 precipitates on the current density of melt processed YBa2Cu3Ox superconductor

International Nuclear Information System (INIS)

Salama, K.; Selvamanickam, V.

1992-01-01

YBa 2 Cu 3 O x superconductors fabricated by melt processing methods have been shown to exhibit current density around 10 5 A/cm 2 at 77 K. Since YBa 2 Cu 3 O x decomposes peritectically above 1000 C, more than 50 vol. % of Y 2 BaCuO 5 (211) precipitates are formed during the incongruent melting. Even under stringent slow cooling conditions, a significant amount of these precipitates remain unreacted with the liquid and are left embedded in the long 123 grains. The potential of these precipitates as flux pinning sites has been investigated extensively, but remains controversial. In this study, we have performed transport current density measurements on melt processed YBa 2 Cu 3 O x superconductor prepared with varying amount of 211 precipitates. The current density measurements were performed in magnetic fields up to 1.5 T at 77 K with the field aligned at different angles to the a-b plane. The results provided in this paper show that Jc decreases monotonically with increasing amount of 211, irrespective of the angle between the field and the a-b plane indicating the absence of significant pinning by 211 precipitates in melt processed YBa 2 Cu 3 O x superconductor
Simple solution-processed CuO{sub X} as anode buffer layer for efficient organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Shen, Wenfei [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Yang, Chunpeng [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Sun, Liang; Wang, Ning [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Tang, Jianguo [Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Chen, Weichao [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Yang, Renqiang, E-mail: yangrq@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China)

2015-10-15

Graphical abstract: - Highlights: • Simple solution-processed CuO{sub X} hole transport layer for efficient organic solar cell. • Good photovoltaic performances as hole transport layer in OSCs with P3HT and PBDTTT-C as donor materials. • The device with CuO{sub X} as hole transport layer shows great improved stability compared with that of device with PEDOT:PSS as hole transport layer. - Abstract: A simple, solution-processed ultrathin CuO{sub X} anode buffer layer was fabricated for high performance organic solar cells (OSCs). XPS measurement demonstrated that the CuO{sub X} was the composite of CuO and Cu{sub 2}O. The CuO{sub X} modified ITO glass exhibit a better surface contact with the active layer. The photovoltaic performance of the devices with CuO{sub X} layer was optimized by varying the thickness of CuO{sub X} films through changing solution concentration. With P3HT:PC{sub 61}BM as the active layer, we demonstrated an enhanced PCE of 4.14% with CuO{sub X} anode buffer layer, compared with that of PEDOT:PSS layer. The CuO{sub X} layer also exhibits efficient photovoltaic performance in devices with PBDTTT-C:PC{sub 71}BM as the active layer. The long-term stability of CuO{sub X} device is better than that of PEDOT:PSS device. The results indicate that the easy solution-processed CuO{sub X} film can act as an efficient anode buffer layer for high-efficiency OSCs.
Microanalysis on CuInSe2 compound synthesized by mechanochemical processing

International Nuclear Information System (INIS)

Wu Sumei; Xue Yuzhi; Zhang Zhihua

2010-01-01

CuInSe 2 (CIS) compound has been synthesized by mechanochemical processing (MCP) with different process parameters. The effect of milling time and different molar ratios of Cu:In:Se was investigated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) for evaluating their crystal structure, grain size, morphology and composition. Field emission transmission electron microscopy (FETEM) was used to detect the smog particles produced during the milling. The results revealed that the obtained powder was chalcopyrite CuInSe 2 and the particle size was smaller than 5 μm after milling for 60 min. The EDS analysis indicated that the smog was volatile selenium. The composition of the products deviated from those of starting materials after MCP. The mechanism about mechanically induced self-propagating reaction which occurred during milling copper, indium and selenium powders was also discussed.
Hot Deformation Behavior and Processing Maps of Diamond/Cu Composites

Science.gov (United States)

Zhang, Hongdi; Liu, Yue; Zhang, Fan; Zhang, Di; Zhu, Hanxing; Fan, Tongxiang

2018-06-01

The hot deformation behaviors of 50 vol pct uncoated and Cr-coated diamond/Cu composites were investigated using hot isothermal compression tests under the temperature and strain rate ranging from 1073 K to 1273 K (800 °C to 1000 °C) and from 0.001 to 5 s-1, respectively. Dynamic recrystallization was determined to be the primary restoration mechanism during deformation. The Cr3C2 coating enhanced the interfacial bonding and resulted in a larger flow stress for the Cr-coated diamond/Cu composites. Moreover, the enhanced interfacial affinity led to a higher activation energy for the Cr-coated diamond/Cu composites (238 kJ/mol) than for their uncoated counterparts (205 kJ/mol). The strain-rate-dependent constitutive equations of the diamond/Cu composites were derived based on the Arrhenius model, and a high correlation ( R = 0.99) was observed between the calculated flow stresses and experimental data. With the help of processing maps, hot extrusions were realized at 1123 K/0.01 s-1 and 1153 K/0.01 s-1 (850 °C/0.01 s-1 and 880 °C/0.01 s-1) for the uncoated and coated diamond/Cu composites, respectively. The combination of interface optimization and hot extrusion led to increases of the density and thermal conductivity, thereby providing a promising route for the fabrication of diamond/Cu composites.
Gradient nanostructured surface of a Cu plate processed by incremental frictional sliding

DEFF Research Database (Denmark)

Hong, Chuanshi; Huang, Xiaoxu; Hansen, Niels

2015-01-01

The flat surface of a Cu plate was processed by incremental frictional sliding at liquid nitrogen temperature. The surface treatment results in a hardened gradient surface layer as thick as 1 mm in the Cu plate, which contains a nanostructured layer on the top with a boundary spacing of the order...
Physical mechanisms of Cu-Cu wafer bonding

International Nuclear Information System (INIS)

Rebhan, B.

2014-01-01

Modern manufacturing processes of complex integrated semiconductor devices are based on wafer-level manufacturing of components which are subsequently interconnected. When compared with classical monolithic bi-dimensional integrated circuits (2D ICs), the new approach of three-dimensional integrated circuits (3D ICs) exhibits significant benefits in terms of signal propagation delay and power consumption due to the reduced metal interconnection length and allows high integration levels with reduced form factor. Metal thermo-compression bonding is a process suitable for 3D interconnects applications at wafer level, which facilitates the electrical and mechanical connection of two wafers even processed in different technologies, such as complementary metal oxide semiconductor (CMOS) and microelectromechanical systems (MEMS). Due to its high electrical conductivity, copper is a very attractive material for electrical interconnects. For Cu-Cu wafer bonding the process requires typically bonding for around 1 h at 400°C and high contact pressure applied during bonding. Temperature reduction below such values is required in order to solve issues regarding (i) throughput in the wafer bonder, (ii) wafer-to-wafer misalignment after bonding and (iii) to minimise thermo-mechanical stresses or device degradation. The aim of this work was to study the physical mechanisms of Cu-Cu bonding and based on this study to further optimise the bonding process for low temperatures. The critical sample parameters (roughness, oxide, crystallinity) were identified using selected analytical techniques and correlated with the characteristics of the bonded Cu-Cu interfaces. Based on the results of this study the impact of several materials and process specifications on the bonding result were theoretically defined and experimentally proven. These fundamental findings subsequently facilitated low temperature (LT) metal thermo-compression Cu-Cu wafer bonding and even room temperature direct
Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys

International Nuclear Information System (INIS)

Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

2016-01-01

Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti 2 Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti 2 Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (> 99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. - Highlights: • Hot extrusion refined the grain size and Ti 2 Cu phase significantly. • Hot extrusion increased the mechanical properties and the corrosion resistance. • The antibacterial properties was not affected by the hot process.
Alleviation of process-induced cracking of the antireflection TiN coating (ARC-TiN) in Al-Cu and Al-Cu-Si films

CERN Document Server

Peng, Y C; Yang, Y R; Hsieh, W Y; Hsieh, Y F

1999-01-01

The alleviation of cracking of the TiN-ARC layer on Al-Cu and Al-Cu-Si films after the development process has been achieved. For the TiN-ARC/Al-Cu system, the stress-induced defects decreased with increasing TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling, thereby inducing poor coverage with high aspect-ratio holes. As a result, the photoresist developer penetrated through the films. Chemical vapor deposition of TiN-ARC or predeposition of a Ti Interposing layer was used to eliminate the formation of Si nodules.
Biodegradation of CuTETA, an effluent by-product in mineral processing.

Science.gov (United States)

Cushing, Alexander M L; Kelebek, Sadan; Yue, Siqing; Ramsay, Juliana A

2018-04-13

Polyamines such as triethylenetetramine (TETA) and other amine chelators are used in mineral processing applications. Formation of heavy metal complexes of these reagents as a by-product in effluent water is a recent environmental concern. In this study, Paecilomyces sp. was enriched from soil on TETA as the sole source of carbon and nitrogen and was found to degrade > 96 and 90% CuTETA complexes at initial concentrations of 0.32 and 0.79 mM respectively, following 96-h incubation. After destabilization, most of the copper (> 78%) was complexed extracellularly and the rest was associated with the cell. Mass spectroscopy results provided confirmation that copper re-complexed with small, extracellular, and organic molecules. There are no reports in the literature that Paecilomyces or any other organism can grow on TETA or CuTETA. This study is the first to show that biological destabilization of CuTETA complexes in mineral processing effluents is feasible.
Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

Science.gov (United States)

Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

2016-12-01

Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. Copyright © 2016 Elsevier B.V. All rights reserved.
Synthesis of Cu-coated Graphite Powders Using a Chemical Reaction Process

Energy Technology Data Exchange (ETDEWEB)

Jang, Jun-Ho; Park, Hyun-Kuk; Oh, Ik-Hyun [Korea Institute of Industrial Technology (KITECH), Gwangju (Korea, Republic of); Lim, Jae-Won [Chonbuk National University, Jeonju (Korea, Republic of)

2017-05-15

In this paper, Cu-coated graphite powders for a low thermal expansion coefficient and a high thermal conductivity are fabricated using a chemical reaction process. The Cu particles adhere to the irregular graphite powders and they homogeneously disperse in the graphite matrix. Cu-coated graphite powders are coarser at approximately 3-4 μm than the initial graphite powders; furthermore, their XRD patterns exhibit a low intensity in the oxide peak with low Zn powder content. For the passivation powders, the transposition solvent content has low values, and the XRD pattern of the oxide peaks is almost non-existent, but the high transposition solvent content does not exhibit a difference to the non-passivation treated powders.
Melt spin processing and recrystallization of REBa2Cu3O7-x

International Nuclear Information System (INIS)

Folkerts, T.J.; Kramer, M.J.; Dennis, K.W.; McCallum, R.W.

1992-01-01

This paper introduces a containerless melt-spin processing technique for REBa 2 Cu 3 O 7-x using pre-reacted oxide powders which are rapidly melted and subsequentially quenched in a controlled atmosphere. This results in flakes with typical dimensional of 3000 x 150 x 15μm 3 . Gd123 and Nd123 form nearly amorphous ribbons with only minor BaCu 2 O 2 when dropped in N 2 . Y123 contains Y 2 O 3 , but that the Ba-Cu-P phases present depend on the processing parameters. SEM and TEM studies show these phases are finely diapered; the typical grain size for Y 2 O 3 is 1-2μm, and for the Ba-Cu-O phases it is <0.5μm. Upon recrystallization from the amorphous ribbon, the Gd123 and Nd123 form field directly into the 123 phase while the recrystallization of the Y123 ribbons is less direct
The electrical conductivity of CuCrZr alloy after SPD processing

International Nuclear Information System (INIS)

Lipińska, M; Bazarnik, P; Lewandowska, M

2014-01-01

CuCrZr alloys exhibit very good relation between mechanical properties and electrical conductivity. However, for its use in some advanced applications improvement of mechanical strength while preserving high electrical conducting is required. Therefore, in this work a CuCrZr alloy was subjected to a series of thermo-mechanical treatments, including solution annealing and water quenching, SPD processing (using hydrostatic extrusion and ECAP) as well as aging in order to improve mechanical strength. The influence of these processing procedures on microstructure features and mechanical properties was determined by TEM observation and microhardness measurements, respectively. Electrical conductivity of the samples was measured by four-points method. The results have shown that it is possible to improve mechanical strength while preserving good electrical conductivity by a proper combination of SPD processing and heat treatment
Cu-62, Cu-64 and Cu-66 production with 4.2 MeV deuterons

International Nuclear Information System (INIS)

Avila, Mario; Morales, J.R.; Riquelme, H.O.

1996-01-01

Full text: The natural copper irradiation with deuterons produces the Cu-62, Cu-64 and Cu-66 radionuclides. Of two radioisotopes, those with deficiencies in neutrons, are applied in nuclear medicine diagnostic processes, mainly for the nuclear characteristic of the decay modes. The positron emitters, of short life mean Cu-62 (9.1 min, β + ) and Cu(12.7 h), are radionuclides applied in radio pharmacological preparation for brain, core, blood flux studies. The radiochemical process consists in the de solution of the irradiated metallic copper target, in acid medium. The result solution, can be neutralized with a base or a buffer at wished pH. Using a deuteron beam of 4,2 ± 0,1 MeV energy has been obtained total yields of 1,103 ± 0,011 μCl/μAh medium for 62 Cu and of 0,148 ± 0,015 μCl/μAh for 64 Cu
In Situ Study of Reduction Process of CuO Paste and Its Effect on Bondability of Cu-to-Cu Joints

Science.gov (United States)

Yao, Takafumi; Matsuda, Tomoki; Sano, Tomokazu; Morikawa, Chiaki; Ohbuchi, Atsushi; Yashiro, Hisashi; Hirose, Akio

2018-04-01

A bonding method utilizing redox reactions of metallic oxide microparticles achieves metal-to-metal bonding in air, which can be alternative to lead-rich high-melting point solder. However, it is known that the degree of the reduction of metallic oxide microparticles have an influence on the joint strength using this bonding method. In this paper, the reduction behavior of CuO paste and its effect on Cu-to-Cu joints were investigated through simultaneous microstructure-related x-ray diffraction and differential scanning calorimetry measurements. The CuO microparticles in the paste were gradually reduced to submicron Cu2O particles at 210-250°C. Subsequently, Cu nanoparticles were generated instantaneously at 300-315°C. There was a marked difference in the strengths of the joints formed at 300°C and 350°C. Thus, the Cu nanoparticles play a critical role in sintering-based bonding using CuO paste. Furthermore, once the Cu nanoparticles have formed, the joint strength increases with higher bonding temperature (from 350°C to 500°C) and pressure (5-15 MPa), which can exceed the strength of Pb-5Sn solder at higher temperature and pressure.
Phase transformation and microstructural changes during ageing process of an Ag-Pd-Cu-Au alloy

Energy Technology Data Exchange (ETDEWEB)

Yu, Chin-Ho; Park, Mi-Gyoung; Kwon, Yong Hoon; Seol, Hyo-Joung [Department of Dental Materials, School of Dentistry and Medical Research Institute, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Kim, Hyung-Il [Department of Dental Materials, School of Dentistry and Medical Research Institute, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of)], E-mail: hilkim@pusan.ac.kr

2008-07-28

Age-hardening behaviour and the related phase transformation and microstructural changes during isothermal ageing process were studied to elucidate the age-hardening mechanism of an Ag-based dental casting alloy composed of Ag-Pd-Cu-Au-Zn, Ir and In by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and energy dispersive spectroscopic microanalysis (EDS). In the hardness test at 350 and 400 deg. C, the hardness of the solution-treated specimen began to increase and reached a maximum value with increasing ageing time, and subsequently the hardness decreased gradually. By considering XRD results and SEM observations together, the solution-treated specimen consisted of three phases, the Ag-rich {alpha}{sub 1} phase as a matrix, the Cu-Pd {alpha}{sub 2} phase and the CuPd {beta} phase with a CsCl-type as particle-like structures. By ageing the solution-treated specimen, the Ag-rich {alpha}{sub 1} and Cu-Pd {alpha}{sub 2} phases were transformed into the Ag-rich {alpha}{sup '}{sub 1} and Cu{sub 3}Pd {alpha}{sup '}{sub 2} phases, respectively. The CuPd {beta} phase with a CsCl-type was not changed apparently during the ageing process. From the results of the hardness test, XRD study, SEM observations and EDS analysis, it could be derived that the hardness increased by the diffusion and precipitation of the Cu-rich phase from the Ag-rich matrix during the early stage of phase transformation of {alpha}{sub 1} into {alpha}{sup '}{sub 1} and that the progress of coarsening of the Cu-rich precipitates with an entanglement structure caused the hardness decrease during the later stage of phase transformation of {alpha}{sub 1} into {alpha}{sup '}{sub 1}. The particle-like structures composed of the Cu-Pd {alpha}{sub 2} and the CuPd {beta} phase with a CsCl-type contributed little to the hardness increase which occurred in the early stage of aging process.
Simple thermodynamic model of the extension of solid solution of Cu-Mo alloys processed by mechanical alloying

International Nuclear Information System (INIS)

Aguilar, C.; Guzman, D.; Rojas, P.A.; Ordonez, Stella; Rios, R.

2011-01-01

Highlights: → Extension of solid solution in Cu-Mo systems achieved by mechanical alloying. → Simple thermodynamic model to explain extension of solid solution of Mo in Cu. → Model gives results that are consistent with the solubility limit extension reported in other works. - Abstract: The objective of this work is proposing a simple thermodynamic model to explain the increase in the solubility limit of the powders of the Cu-Mo systems or other binary systems processed by mechanical alloying. In the regular solution model, the effects of crystalline defects, such as; dislocations and grain boundary produced during milling were introduced. The model gives results that are consistent with the solubility limit extension reported in other works for the Cu-Cr, Cu-Nb and Cu-Fe systems processed by mechanical alloying.
CuO reduction induced formation of CuO/Cu2O hybrid oxides

Science.gov (United States)

Yuan, Lu; Yin, Qiyue; Wang, Yiqian; Zhou, Guangwen

2013-12-01

Reduction of CuO nanowires results in the formation of a unique hierarchical hybrid nanostructure, in which the parent oxide phase (CuO) works as the skeleton while the lower oxide (Cu2O) resulting from the reduction reaction forms as partially embedded nanoparticles that decorate the skeleton of the parent oxide. Using in situ transmission electron microscopy observations of the reduction process of CuO nanowires, we demonstrate that the formation of such a hierarchical hybrid oxide structure is induced by topotactic nucleation and growth of Cu2O islands on the parent CuO nanowires.
Fabrication of Copper-Rich Cu-Al Alloy Using the Wire-Arc Additive Manufacturing Process

Science.gov (United States)

Dong, Bosheng; Pan, Zengxi; Shen, Chen; Ma, Yan; Li, Huijun

2017-12-01

An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate Cu-9 at. pct Al on pure copper plates in situ, through separate feeding of pure Cu and Al wires into a molten pool, which is generated by the gas tungsten arc welding (GTAW) process. After overcoming several processing problems, such as opening the deposition molten pool on the extremely high-thermal conductive copper plate and conducting the Al wire into the molten pool with low feed speed, the copper-rich Cu-Al alloy was successfully produced with constant predesigned Al content above the dilution-affected area. Also, in order to homogenize the as-fabricated material and improve the mechanical properties, two further homogenization heat treatments at 1073 K (800 °C) and 1173 K (900 °C) were applied. The material and mechanical properties of as-fabricated and heat-treated samples were compared and analyzed in detail. With increased annealing temperatures, the content of precipitate phases decreased and the samples showed gradual improvements in both strength and ductility with little variation in microstructures. The present research opened a gate for in-situ fabrication of Cu-Al alloy with target chemical composition and full density using the additive manufacturing process.

Numerical Analysis of Warpage Induced by Thermo-Compression Bonding Process of Cu Pillar Bump Flip Chip Package

Energy Technology Data Exchange (ETDEWEB)

Kwon, Oh Young; Jung, Hoon Sun; Lee, Jung Hoon; Choa, Sung-Hoon [Seoul Nat’l Univ. of Science and Technology, Seoul (Korea, Republic of)

2017-06-15

In flip chip technology, the conventional solder bump has been replaced with a copper (Cu) pillar bump owing to its higher input/output (I/O) density, finer pitch, and higher reliability. However, Cu pillar bump technology faces several issues, such as interconnect shorting and higher low-k stress due to stiffer Cu pillar structure when the conventional reflow process is used. Therefore, the thermal compression bonding (TCB) process has been adopted in the flip chip attachment process in order to reduce the package warpage and stress. In this study, we investigated the package warpage induced during the TCB process using a numerical analysis. The warpage of the TCB process was compared with that of the reflow process.
Heap leaching of Cu contaminated soil with [S,S]-EDDS in a closed process loop

International Nuclear Information System (INIS)

Finzgar, Neza; Zumer, Alenka; Lestan, Domen

2006-01-01

Heap leaching of Cu contaminated soil (412 ± 11 mg kg -1 ) with 5 mmol kg -1 ethylenediamine disuccinate [S,S]-EDDS as a chelator was tested in a laboratory-scale soil column study. The washing solution was recycled in a closed process loop after microbial (using a microbially active permeable bed, composed of substrate and absorbent) and oxidative chemical (using combined ozonation and UV irradiation) degradation of metal-[S,S]-EDDS complexes and retention of released Cu on a commercial absorbent Slovakite. Heap leaching using the permeable bed removed 25.5 ± 3.6% of initial total Cu from the soil. Ozone/UV treatment of the [S,S]-EDDS washing solution removed much more, 47.5 ± 7.4%, of Cu. Both methods yielded a clear and colorless final (waste) washing solution, with 7.0 ± 10.0 and 2.6 ± 0.7 mg L -1 Cu (permeable bed and ozone/UV method, respectively). The results of our study indicate that chemical treatment of chelator washing solution with ozone/UV in a closed process loop could lead to the development of a new, efficient and environmentally safe remediation method with controllable Cu emissions
Kinetic process of mechanical alloying in Fe50Cu50

DEFF Research Database (Denmark)

Huang, J.Y.; Jiang, Jianzhong; Yasuda, H.

1998-01-01

It is shown that mechanical alloying in the immiscible Fe-Cu system is governed by the atomic shear event and shear-induced diffusion process. We found that an alpha-to-gamma phase transformation, as evidenced by the Nishiyama-Wasserman orientation relationship, occurs by simultaneous shearing...
Optimization of a Cu CMP process modeling parameters of nanometer integrated circuits

International Nuclear Information System (INIS)

Ruan Wenbiao; Chen Lan; Ma Tianyu; Fang Jingjing; Zhang He; Ye Tianchun

2012-01-01

A copper chemical mechanical polishing (Cu CMP) process is reviewed and analyzed from the view of chemical physics. Three steps Cu CMP process modeling is set up based on the actual process of manufacturing and pattern-density-step-height (PDSH) modeling from MIT. To catch the pattern dependency, a 65 nm testing chip is designed and processed in the foundry. Following the model parameter extraction procedure, the model parameters are extracted and verified by testing data from the 65 nm testing chip. A comparison of results between the model predictions and test data show that the former has the same trend as the latter and the largest deviation is less than 5 nm. Third party testing data gives further evidence to support the great performance of model parameter optimization. Since precise CMP process modeling is used for the design of manufacturability (DFM) checks, critical hotspots are displayed and eliminated, which will assure good yield and production capacity of IC. (semiconductor technology)
Cu-62, Cu-64 and Cu-66 production with 4.2 MeV deuterons; Produccion de {sup 62} Cu y {sup 64} Cu con deuterones de 4,2 MeV

Energy Technology Data Exchange (ETDEWEB)

Avila, Mario; Morales, J R; Riquelme, H O [Chile Univ., Santiago (Chile). Facultad de Ciencias. Dept. de Fisica

1997-12-31

Full text: The natural copper irradiation with deuterons produces the Cu-62, Cu-64 and Cu-66 radionuclides. Of two radioisotopes, those with deficiencies in neutrons, are applied in nuclear medicine diagnostic processes, mainly for the nuclear characteristic of the decay modes. The positron emitters, of short life mean Cu-62 (9.1 min, {beta}{sup +}) and Cu(12.7 h), are radionuclides applied in radio pharmacological preparation for brain, core, blood flux studies. The radiochemical process consists in the de solution of the irradiated metallic copper target, in acid medium. The result solution, can be neutralized with a base or a buffer at wished pH. Using a deuteron beam of 4,2 {+-} 0,1 MeV energy has been obtained total yields of 1,103 {+-} 0,011 {mu}Cl/{mu}Ah medium for 62 Cu and of 0,148 {+-} 0,015 {mu}Cl/{mu}Ah for 64 Cu.
Significance of stacking fault energy on microstructural evolution in Cu and Cu-Al alloys processed by high-pressure torsion

Science.gov (United States)

An, X. H.; Lin, Q. Y.; Wu, S. D.; Zhang, Z. F.; Figueiredo, R. B.; Gao, N.; Langdon, T. G.

2011-09-01

Disks of pure Cu and several Cu-Al alloys were processed by high-pressure torsion (HPT) at room temperature through different numbers of turns to systematically investigate the influence of the stacking fault energy (SFE) on the evolution of microstructural homogeneity. The results show there is initially an inhomogeneous microhardness distribution but this inhomogneity decreases with increasing numbers of turns and the saturation microhardness increases with increasing Al concentration. Uniform microstructures are more readily achieved in materials with high or low SFE than in materials with medium SFE, because there are different mechanisms governing the microstructural evolution. Specifically, recovery processes are dominant in high or medium SFE materials, whereas twin fragmentation is dominant in materials having low SFE. The limiting minimum grain size (d min) of metals processed by HPT decreases with decreasing SFE and there is additional evidence suggesting that the dependence of d min on the SFE decreases when the severity of the external loading conditions is increased.
Uncovering the Problem-Solving Process: Cued Retrospective Reporting Versus Concurrent and Retrospective Reporting

OpenAIRE

Van Gog, Tamara; Paas, Fred; Van Merriënboer, Jeroen; Witte, P.

2007-01-01

This study investigated the amounts of problem-solving process information ("action," "why," "how," and "metacognitive") elicited by means of concurrent, retrospective, and cued retrospective reporting. In a within-participants design, 26 participants completed electrical circuit troubleshooting tasks under different reporting conditions. The method of cued retrospective reporting used the original computer-based task and a superimposed record of the participant's eye fixations and mouse-keyb...
Synthesis and characterization of CuO flower-nanostructure processing by a domestic hydrothermal microwave

International Nuclear Information System (INIS)

Volanti, D.P.; Keyson, D.; Cavalcante, L.S.; Simoes, A.Z.; Joya, M.R.; Longo, E.; Varela, J.A.; Pizani, P.S.; Souza, A.G.

2008-01-01

The synthesis and characterization of CuO flower-nanostructure processed in domestic hydrothermal microwave oven was presented. Phase analysis was carried out using X-ray diffraction (XRD) and micro-Raman scattering (MRS) and the results confirmed the CuO flower-nanostructure as a single-phase. The field-emission scanning electron microscopy (FEG-SEM) was used to estimate the average spheres diameter while transmission electron microscope (TEM) to observe the thorn of the flower-nanostructures. The mechanism of CuO flower-nanostructures formation is proposed and explained
Synthesis and characterization of CuO flower-nanostructure processing by a domestic hydrothermal microwave

Energy Technology Data Exchange (ETDEWEB)

Volanti, D.P. [Laboratorio Interdisciplinar em Ceramica, Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP (Brazil); Keyson, D. [Laboratorio de Ensino de Ciencias e Laboratorio de Combustiveis e Materiais, Departamento de Quimica, Universidade Federal da Paraiba, 58051-900 Joao Pessoa, PB (Brazil); Cavalcante, L.S. [Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, Universidade Federal de Sao Carlos, P.O. Box 676, 13565-905 Sao Carlos, SP (Brazil)], E-mail: laeciosc@bol.com.br; Simoes, A.Z. [Laboratorio Interdisciplinar em Ceramica, Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP (Brazil); Joya, M.R. [Departamento de Fisica, Universidade Federal de Sao Carlos, P.O. Box 676, 13565-905 Sao Carlos, SP (Brazil); Longo, E.; Varela, J.A. [Laboratorio Interdisciplinar em Ceramica, Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP (Brazil); Pizani, P.S. [Departamento de Fisica, Universidade Federal de Sao Carlos, P.O. Box 676, 13565-905 Sao Carlos, SP (Brazil); Souza, A.G. [Laboratorio de Ensino de Ciencias e Laboratorio de Combustiveis e Materiais, Departamento de Quimica, Universidade Federal da Paraiba, 58051-900 Joao Pessoa, PB (Brazil)

2008-07-14

The synthesis and characterization of CuO flower-nanostructure processed in domestic hydrothermal microwave oven was presented. Phase analysis was carried out using X-ray diffraction (XRD) and micro-Raman scattering (MRS) and the results confirmed the CuO flower-nanostructure as a single-phase. The field-emission scanning electron microscopy (FEG-SEM) was used to estimate the average spheres diameter while transmission electron microscope (TEM) to observe the thorn of the flower-nanostructures. The mechanism of CuO flower-nanostructures formation is proposed and explained.
Processing of Cu-Cr alloy for combined high strength and high conductivity

Directory of Open Access Journals (Sweden)

A.O Olofinjanaa

2017-11-01

Full Text Available High strength and high conductivity (HSHC are two intrinsic properties difficult to combine in metallic alloy design because; almost all strengthening mechanisms also lead to reduced conductivity. Precipitation hardening by nano-sized precipitates had proven to be the most adequate way to achieve the optimum combination of strength and conductivity in copper based alloys. However, established precipitation strengthened Cu- alloys are limited to very dilute concentration of solutes thereby limiting the volume proportion hardening precipitates. In this work, we report the investigation of the reprocessing of higher Cr concentration Cu- based alloys via rapid solidification. It is found that the rapid solidification in the as-cast ribbon imposed combined solution extension and ultra-refinement of Cr rich phases. X-ray diffraction evidences suggest that the solid solution extension was up to 6wt%Cr. Lattice parameters determined confirmed the many folds extension of solid solution of Cr in Cu. Thermal aging studies of the cast ribbons indicated that peak aging treatments occurred in about twenty minutes. Peak aged hardness ranged from about 200 to well over 300Hv. The maximum peak aged hardness of 380Hv was obtained for alloy containing 6wt.%Cr but with conductivity of about 50%IACS. The best combined strength/conductivity was obtained for 4wt.%Cr alloy with hardness of 350HV and conductivity of 80% IACS. The high strengths observed are attributed to the increased volume proportion of semi-coherent Cr rich nano-sized precipitates that evolved from the supersaturated solid solution of Cu-Cr that was achieved from the high cooling rates imposed by the ribbon casting process. The rapid overaging of the high Cr concentration Cu-Cr alloy is still a cause for concern in optimising the process for reaching peak HSHC properties. It is still important to investigate a microstructural design to slow or severely restrict the overaging process. The optimum
Uncovering the problem-solving process: cued retrospective reporting versus concurrent and retrospective reporting.

Science.gov (United States)

van Gog, Tamara; Paas, Fred; van Merriënboer, Jeroen J G; Witte, Puk

2005-12-01

This study investigated the amounts of problem-solving process information ("action," "why," "how," and "metacognitive") elicited by means of concurrent, retrospective, and cued retrospective reporting. In a within-participants design, 26 participants completed electrical circuit troubleshooting tasks under different reporting conditions. The method of cued retrospective reporting used the original computer-based task and a superimposed record of the participant's eye fixations and mouse-keyboard operations as a cue for retrospection. Cued retrospective reporting (with the exception of why information) and concurrent reporting (with the exception of metacognitive information) resulted in a higher number of codes on the different types of information than did retrospective reporting.
Melt-processed LRE-Ba-Cu-O superconductors and prospects for their applications

International Nuclear Information System (INIS)

Yoo, S.I.; Fujimoto, H.; Sakai, N.; Murakami, M.

1997-01-01

We have recently found that control of the oxygen partial pressure (PO 2 ) during melt processing, named the oxygen-controlled melt-growth (OCMG) process, is critical for obtaining a high superconducting transition temperature (T c ) in the light rare earth (LRE)-Ba-Cu-O (LREBCO) superconductors particularly for Nd, Sm and Eu. Further, compared to a good melt-processed Y-Ba-Cu-O (YBCO) bulk superconductor, LREBCO bulks exhibit larger critical current density (J c ) in high magnetic field and a much improved irreversibility field (H irr ) at 77 K, implying that more effective flux pinning can be realized in a commercially feasible way. In this paper, properties and characteristic flux pinning of OCMG-processed LREBCO (LRE: Nd,Sm,Eu) superconductors are described on the basis of our study during the last several years. We also present the prospects for bulk-type applications, such as the magnetic bearings, flywheels and magnetically levitated (MAGLEV) trains. (orig.)
Investigation of microstructure and properties of ultrathin graded ZrNx self-assembled diffusion barrier in deep nano-vias prepared by plasma ion immersion implantation

Science.gov (United States)

Zou, Jianxiong; Liu, Bo; Lin, Liwei; Lu, Yuanfu; Dong, Yuming; Jiao, Guohua; Ma, Fei; Li, Qiran

2018-01-01

Ultrathin graded ZrNx self-assembled diffusion barriers with controllable stoichiometry was prepared in Cu/p-SiOC:H interfaces by plasma immersion ion implantation (PIII) with dynamic regulation of implantation fluence. The fundamental relationship between the implantation fluence of N+ and the stoichiometry and thereby the electrical properties of the ZrNx barrier was established. The optimized fluence of a graded ZrN thin film with gradually decreased Zr valence was obtained with the best electrical performance as well. The Cu/p-SiOC:H integration is thermally stable up to 500 °C due to the synergistic effect of Cu3Ge and ZrNx layers. Accordingly, the PIII process was verified in a 100-nm-thick Cu dual-damascene interconnect, in which the ZrNx diffusion barrier of 1 nm thick was successfully self-assembled on the sidewall without barrier layer on the via bottom. In this case, the via resistance was reduced by approximately 50% in comparison with Ta/TaN barrier. Considering the results in this study, ultrathin ZrNx conformal diffusion barrier can be adopted in the sub-14 nm technology node.
Microstructure and associated properties of YBa2Cu3Ox superconductors prepared by melt-processing techniques

International Nuclear Information System (INIS)

Balachandran, U.; Zhong, W.; Youngdahl, C.A.; Poeppel, R.B.

1993-03-01

From the standpoint of applications, melt-processed bulk YBa 2 Cu 3 O x (YBCO) superconductors are of considerable interest. We have studied the microstructure and levitation force of melt-processed YBCO, YBCO plus Y 2 BaCuO 5 , and YBCO plus Pt samples. Large single crystalline samples, grown using a seeding technique, were also studied. The levitation force is highest in melt-processed samples made by the seeding technique. 6 figs, 24 refs
Cu and Zn Isotopes as New Tracers of Early Solar Nebula and Asteroidal processes

Science.gov (United States)

LUCK, J.; BEN OTHMAN, D.; ALBAREDE, F.

2001-12-01

Cu and Zn isotopic variations are now identified in extra-terrestrial samples, as has been the case for terrestrial samples (1). The main parameters which may cause these variations are : redox state, temperature, biological activity (Earth), and volatility (extra-terrestrial samples). We report data for meteorites from various groups and classes, including carbonaceous chondrites, ordinary and diffentiated chondrites (iron meteorites, SNC and HED). All analyses have been duplicated (from powder aliquot to final measurement). Values are expressed as relative deviations from NIST and JMC standards for 65Cu/63Cu and 66Zn64Zn, respectively (deltas in permil). Carefull chemistry and MC-ICP-MS measurements allow an overall precision of +/-0.04 permil. I- Carbonaceous Chondrites A very important feature is that each group seems to exhibit a specific isotopic signature : Cu gets isotopically lighter from CI to CM to CO to CV, spanning an overall range of 1.5 permil. Zn shows a reverse order, getting heavier from CI to CM to CO. Zn in CV chondrites (whole rock) seems more variable. This order is the same as that observed for trace elements. Cu and Zn isotopic compositions are generally correlated to trace element content from one group to another, particularly those of similar volatility (e.g. Mn for Cu; Ge for Zn). Cu and Zn isotopic signatures exhibit remarkable relationships with Oxygen isotopes. Each group is well identified. Cu is linearly correlated with Oxygen, whereas Zn-O data display strong curvature : the difference in shape can be related to the nearly constant Cu content in all groups, and by the decreasing Zn content from CI to CO. Since Oxygen variations (from CV to CI) are thought to reflect progressive interaction of liquid water with initial solid (asteroid), Cu isotopic variations may also reflect this progressive alteration process. It may be so for Zn too, although its more volatile character might play a role. II-Allende Progressive leaching
Neural correlates of encoding processes predicting subsequent cued recall and source memory.

Science.gov (United States)

Angel, Lucie; Isingrini, Michel; Bouazzaoui, Badiâa; Fay, Séverine

2013-03-06

In this experiment, event-related potentials were used to examine whether the neural correlates of encoding processes predicting subsequent successful recall differed from those predicting successful source memory retrieval. During encoding, participants studied lists of words and were instructed to memorize each word and the list in which it occurred. At test, they had to complete stems (the first four letters) with a studied word and then make a judgment of the initial temporal context (i.e. list). Event-related potentials recorded during encoding were segregated according to subsequent memory performance to examine subsequent memory effects (SMEs) reflecting successful cued recall (cued recall SME) and successful source retrieval (source memory SME). Data showed a cued recall SME on parietal electrode sites from 400 to 1200 ms and a late inversed cued recall SME on frontal sites in the 1200-1400 ms period. Moreover, a source memory SME was reported from 400 to 1400 ms on frontal areas. These findings indicate that patterns of encoding-related activity predicting successful recall and source memory are clearly dissociated.
Plasma ash processing solutions for advanced interconnect technology

International Nuclear Information System (INIS)

Fuller, N.C.M.; Worsley, M.A.; Tai, L.; Bent, S.; Labelle, C.; Arnold, J.; Dalton, T.

2008-01-01

A mechanism for the modification of porous ultra low-k (ULK) and extreme ultra low-k (EULK) SiCOH-based materials is proposed. This is achieved by correlating film damage on a patterned structure measured by angular resolved x-ray photoelectron spectroscopy (ARXPS) with corresponding changes in reactive species radical density and ion current in the plasma measured by optical emission spectroscopy (OES), rare gas actinometry, and modeling. Line-to-line electrical leakage and capacitance data of nested line structures exposed to downstream ash plasmas suggest that other etching steps during back-end-of-the-line (BEOL) dual damascene processing are also critical for the overall modification induced to these materials
Processing-property relations in YBa2Cu3O(6+x) superconductors

Science.gov (United States)

Safari, A.; Wachtman, J. B., Jr.; Parkhe, V.; Caracciolo, R.; Jeter, D.

Processing of YBa2Cu3O(6+x) superconducting samples by employing different precursor powder preparation techniques such as ball milling, attrition milling, and narrow particle size distribution powder preparation through coprecipitation by spraying will be discussed. CuO coated with oxalates shows the lowest resistance above Tc up to room temperature. The extent of corrosion by water has been studied by employing magnetic susceptibility, XPS, and X-ray diffraction. Superconducting samples are affected to a considerable extent when treated in water at 60 C and the severity of the attack increases with time.
Electrochemical properties of CuO hollow nanopowders prepared from formless Cu–C composite via nanoscale Kirkendall diffusion process

Energy Technology Data Exchange (ETDEWEB)

Won, Jong Min [Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Kim, Jong Hwa [Daegu Center, Korea Basic Science Institute, 80 Daehakro Bukgu, Daegu 702-701 (Korea, Republic of); Choi, Yun Ju [Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Cho, Jung Sang [Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Kang, Yun Chan, E-mail: yckang@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of)

2016-06-25

Hollow CuO nanopowders are prepared using a simple spray drying process that relied on nanoscale Kirkendall diffusion; these nanopowders have potential applications in lithium-ion batteries. Citric acid is used as both the carbon source material and chelating agent and plays a key role in the preparation of the hollow nanopowders. The formless Cu–C composite that formed as an intermediate product transforms into slightly aggregated CuO hollow nanopowders after post-treatment at 300 and 400 °C under an air atmosphere. The CuO hollow nanopowders exhibit higher initial discharge capacities and better cycling performances than those of the filled-structured CuO nanopowders, which are prepared at a post-treatment temperature of 500 °C under an air atmosphere. The discharge capacities of the CuO nanopowders post-treated at 300, 400, and 500 °C for the 150{sup th} cycle at a current density of 1 A g{sup −1} are 793, 632, and 464 mA h g{sup −1}, respectively, and their capacity retentions calculated from the maximum discharge capacities are 88, 80, and 73%, respectively. The CuO nanopowders with hollow structures exhibit better structural stability for repeated lithium insertion and desertion processes than those with filled structures. - Highlights: • Hollow CuO nanopowders are prepared using a simple spray drying process. • Cu–C composite transforms into CuO hollow nanopowders by Kirkendall diffusion. • Hollow CuO nanopowders show good electrochemical properties for lithium-ion storage.
Flux pinning enhancement by Y2BaCuO5 inclusions in melt processed YBaCuO superconductors

International Nuclear Information System (INIS)

Murakami, M.

1991-01-01

While nonsuperconducting particles are known to serve as effective pinning centers in conventional superconductors, their effect in high T c superconductors is still controversial. In this paper, the author gives evidence that nonsuperconducting Y 2 BaCuO 5 (21 1) inclusions can act as pinning centers in melt processed YBaCuO superconductors even when their size is orders of magnitude larger than the coherence length. In such a case, the interface provides pinning. Theoretical estimates based on direct summations agree well with the experimental results. The applications of direct summation for obtaining the bulk pinning force is justified by direct observation of the FLL (flux line lattice), where the FLL has no long range order and the fluxoids are pinned by 211 inclusions

Electrical and photovoltaic characteristics of CuInSe2 thin films processed by nontoxic Cu–In precursor solutions

International Nuclear Information System (INIS)

Choi, Ik Jin; Jang, Jin Woo; Lee, Seung Min; Yeon, Deuk Ho; Jo, Yeon Hwa; Lee, Myung Ho; Cho, Yong Soo; Yun, Jae Ho; Yoon, Kyung Hoon

2013-01-01

Nontoxic Cu–In solution-processed CuInSe 2 absorber thin films and resultant photovoltaic cells have been investigated. Acetate-based Cu–In precursors having different Cu/In ratios of 0.8–1.2 were deposited by spin-coating and then selenized in Se atmosphere up to 550 °C. Single tetragonal CuInSe 2 phase was dominantly obtained regardless of Cu/In ratios, with the segregation of Cu 2−x Se secondary phase only in the case of Cu-rich films as evidenced by Raman spectra. The films with the 1.1 ratio demonstrated a larger grain size of ∼1.06 µm with an increased carrier concentration of ∼1.7 × 10 18 cm −3 and a decreased band gap of ∼1.02 eV, compared to the values obtained for Cu-deficient absorber films. The resultant best cell efficiency was ∼3.1% for the absorber having the 1.1 ratio, suggesting a potential of this simple spin-coating method as an alternative to typical vacuum processes. (paper)
Microstructure characterization of Cu processed by compression with oscillatory torsion

International Nuclear Information System (INIS)

Rodak, K.; Pawlicki, J.

2014-01-01

High purity Cu (99.9%) was subjected to severe plastic deformation up to a total effective strain ε ft = 130 through compression with the oscillatory torsion method at room temperature. This method produces an ultrafine grain microstructure. The microstructure evolution was investigated with respect to the value of the total effective strain using a scanning electron microscope with an electron-backscattered diffraction technique and a scanning transmission electron microscope. The results of the structural analyses show that increasing ε ft from 2 to 50 causes progress in the grain refinement. A quantitative study of the microstructure parameters, such as fraction of high angle boundaries, grain and subgrain diameter, and the area fraction of grains up to 1 μm, shows that deformation at ε ft = 45 guaranteed the best conditions for refining the microstructure of Cu. Using high values of ε ft in the range 60 to 130 restricts grain refinement because intensive recovery begins to dominate in the microstructure. - Highlights: • Cu was processed by SPD metodto an effective strain 130. • The microstructure evolution has been investigated. • The method allows to produce an ultrafine grain microstructure
Microstructure characterization of Cu processed by compression with oscillatory torsion

Energy Technology Data Exchange (ETDEWEB)

Rodak, K., E-mail: kinga.rodak@polsl.pl [Institute of Materials Science, Silesian University of Technology, Krasińskiego 8, 40-019 Katowice (Poland); Pawlicki, J., E-mail: jacek.pawlicki@polsl.pl [Department of Automotive Vehicle Construction, Silesian University of Technology, Krasińskiego 8, 40–019 Katowice (Poland)

2014-08-15

High purity Cu (99.9%) was subjected to severe plastic deformation up to a total effective strain ε{sub ft} = 130 through compression with the oscillatory torsion method at room temperature. This method produces an ultrafine grain microstructure. The microstructure evolution was investigated with respect to the value of the total effective strain using a scanning electron microscope with an electron-backscattered diffraction technique and a scanning transmission electron microscope. The results of the structural analyses show that increasing ε{sub ft} from 2 to 50 causes progress in the grain refinement. A quantitative study of the microstructure parameters, such as fraction of high angle boundaries, grain and subgrain diameter, and the area fraction of grains up to 1 μm, shows that deformation at ε{sub ft} = 45 guaranteed the best conditions for refining the microstructure of Cu. Using high values of ε{sub ft} in the range 60 to 130 restricts grain refinement because intensive recovery begins to dominate in the microstructure. - Highlights: • Cu was processed by SPD metodto an effective strain 130. • The microstructure evolution has been investigated. • The method allows to produce an ultrafine grain microstructure.
One-step electrodeposition process of CuInSe2: Deposition time effect

Indian Academy of Sciences (India)

Administrator

CuInSe2 thin films were prepared by one-step electrodeposition process using a simplified two- electrodes system. ... homojunctions or heterojunctions (Rincon et al 1983). Efficiency of ... deposition times onto indium thin oxide (ITO)-covered.
High-coercivity ultrafine-grained anisotropic Nd–Fe–B magnets processed by hot deformation and the Nd–Cu grain boundary diffusion process

International Nuclear Information System (INIS)

Sepehri-Amin, H.; Ohkubo, T.; Nagashima, S.; Yano, M.; Shoji, T.; Kato, A.; Schrefl, T.; Hono, K.

2013-01-01

The grain boundary diffusion process using an Nd 70 Cu 30 eutectic alloy has been applied to hot-deformed anisotropic Nd–Fe–B magnets, resulting in a substantial enhancement of coercivity, from 1.5 T to 2.3 T, at the expense of remanence. Scanning electron microscopy showed that the areal fraction of an Nd-rich intergranular phase increased from 10% to 37%. The intergranular phase of the hot-deformed magnet initially contained ∼55 at.% ferromagnetic element, while it diminished to an undetectable level after the process. Microscale eutectic solidification of Nd/NdCu as well as a fine lamellae structure of Nd 70 (Co,Cu) 30 /Nd were observed in the intergranular phase. Micromagnetic simulations indicated that the reduction of the magnetization in the intergranular phases leads to the enhancement of coercivity in agreement with the experimental observation
Decomplexation efficiency and mechanism of Cu(II)-EDTA by H2O2 coupled internal micro-electrolysis process.

Science.gov (United States)

Zhou, Dongfang; Hu, Yongyou; Guo, Qian; Yuan, Weiguang; Deng, Jiefan; Dang, Yapan

2016-12-29

Internal micro-electrolysis (IE) coupled with Fenton oxidation (IEF) was a very effective technology for copper (Cu)-ethylenediaminetetraacetic acid (EDTA) wastewater treatment. However, the mechanisms of Cu 2+ removal and EDTA degradation were scarce and lack persuasion in the IEF process. In this paper, the decomplexation and removal efficiency of Cu-EDTA and the corresponding mechanisms during the IEF process were investigated by batch test. An empirical equation and the oxidation reduction potential (ORP) index were proposed to flexibly control IE and the Fenton process, respectively. The results showed that Cu 2+ , total organic carbon (TOC), and EDTA removal efficiencies were 99.6, 80.3, and 83.4%, respectively, under the proper operation conditions of iron dosage of 30 g/L, Fe/C of 3/1, initial pH of 3.0, Fe 2+ /H 2 O 2 molar ratio of 1/4, and reaction time of 20 min, respectively for IE and the Fenton process. The contributions of IE and Fenton to Cu 2+ removal were 91.2 and 8.4%, respectively, and those to TOC and EDTA removal were 23.3, 25.1, and 57, 58.3%, respectively. It was found that Fe 2+ -based replacement-precipitation and hydroxyl radical (•OH) were the most important effects during the IEF process. •OH played an important role in the degradation of EDTA, whose yield and productive rate were 3.13 mg/L and 0.157 mg/(L min -1 ), respectively. Based on the intermediates detected by GC-MS, including acetic acid, propionic acid, pentanoic acid, amino acetic acid, 3-(diethylamino)-1,2-propanediol, and nitrilotriacetic acid (NTA), a possible degradation pathway of Cu-EDTA in the IEF process was proposed. Graphical abstract The mechanism diagram of IEF process.
Increasing the carbon capture efficiency of the Ca/Cu looping process for power production with advanced process schemes

NARCIS (Netherlands)

Martini, M.; Martinez, I.; Romano, M.C.; Chiesa, P.; Gallucci, F.; van Sint Annaland, M.

2017-01-01

The Ca-Cu process is a novel concept for hydrogen production with inherent CO2 capture that has received great attention in the last years as potential low-CO2 emission technology for power generation and hydrogen production from natural gas. The process is based on the reforming of natural gas in
Antibacterial property of CuCrO{sub 2} nanopowders prepared by a self-combustion glycine nitrate process

Energy Technology Data Exchange (ETDEWEB)

Nien, Yung-Tang, E-mail: ytnien@nfu.edu.tw [Deparment of Materials Science and Engineering, National Formosa University, Yunlin, 63201, Taiwan (China); Hu, Mon-Ru [Deparment of Materials Science and Engineering, National Formosa University, Yunlin, 63201, Taiwan (China); Chiu, Te-Wei [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan (China); Chu, Jaw-Shiow [Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, 30062, Taiwan (China)

2016-08-15

Porous CuCrO{sub 2} nanopowders were prepared via glycine nitrate process (GNP) at 175 °C in ambient air. The X-ray diffraction patterns showed a pure delafossite phase of CuCrO{sub 2} with numerous broad peaks, indicating a crystallite size of approximately 20 nm. The surface area of the CuCrO{sub 2} nanopowders was larger than 50 m{sup 2}/g, nearly 100 times greater than that of bulk powders (0.47 m{sup 2}/g). Pathogenic Gram-negative bacteria Escherichia coli (E. coli) were chosen as the antibacterial evaluation indicators for both the nanopowders and bulk powders. The results showed that 1750 ppm nanopowders inhibited the growth of E. coli. As a control, the bulk powders showed a normal growth profile. The antibacterial property of the CuCrO{sub 2} nanopowders can be attributed to the extremely large surface area, which induces rapid release of Cu ions and strong adhesion of nanopowders to bacteria. - Highlights: • CuCrO{sub 2} nanopowders was prepared by low-temperature glycine nitrate process. • 1250–1500 ppm of CuCrO{sub 2} nanopowders were found to depress the growth of Escherichia coli. • Bulk powders by the solid state reaction exhibited no antibacterial property. • The antibacterial property of nanopowders was attributed to rapid Cu ion releases. • Heavy adhesion of nanopowders to bacteria also resulted in antibacterial property.
Phase formation and reaction kinetics during the processing of the chalkopyrite-solar-cell-material Cu(In,Ga)(Se,S){sub 2}; Phasenbildung und Reaktionskinetik bei der Herstellung des Chalkopyrit-Solarzellenmaterials Cu(In,Ga)(Se,S){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Purwins, Michael

2010-02-05

The SEL/RTP-procedure (Stacked-Elemental-Layer/Rapid-Thermal-Process) is a method which is used to produce CuInSe{sub 2}-based absorbers/semiconductors for the application in thin film solar cells and modules, respectively. The SEL/RTP-procedure consists of two consecutive steps. During the first step a stack of several layers of the metals Cu, Ga and In as well as Se and/or S are deposited onto a substrate to form the so called precursor. By annealing the precursor, reaching temperatures of about 550 C, the stacked layers are converted into the compound semiconductor Cu(In{sub 1-x}Ga{sub x})(S{sub 1-y}Se{sub y}){sub 2} (CIGSSe). During the thermal process the central component of the later solar cell, the highly light absorbing, photoelectric active layer is formed. Thus, the second step is of great importance. This is not only because of the fact that the absorbers physical properties are established by the thermal process. Additionally the profitability of the whole manufacturing process is affected. To be able to optimize the SEL/RTP-procedure a deep and comprehensive understanding of the occurring phase formation processes and reaction kinetic mechanisms associated with them is necessary. This was the goal of the present thesis which therefore deals with the phase formation processes during the deposition of the precursor and its reaction kinetics during the following selenization and sulfurization process. Therefore the influence of different sputtering parameters on the formation of phases and the evolution of the precursor's morphology during its production by sputtering alternating stacked layers of Cu:Ga-alloys (i.e. Cu{sub 85}Ga{sub 15}, Cu{sub 75}Ga{sub 25} and CuGa{sub 2}) and/or the elements Cu and In was investigated. It was found that the deposition of Cu{sub 75/85}Ga{sub 25/15} onto In leads to the formation of CuIn{sub 2} and/or a metastable Cu(In,Ga)-alloy that is rich in copper. This deposition sequence is crucial for the precursor
Study of processes of interligand exchange between Cu(AA)2 and Y(DPM)3 in geseous phase

International Nuclear Information System (INIS)

Girichev, G.V.; Giricheva, N.I.; Belova, N.V.; Kuz'mina, N.P.; Kaul', A.R.; Gorbenko, O.Yu.

1993-01-01

Mass-spectrometric method was used to study the process, proceeding between gaseous copper acetylacetonate and yttrium dipivaloylmethanate in 150-630 deg C range. It was established that intensive ligand exchange with formation of Cu(DPM) (AA), Y(DPM) 2 (AA), Cu(DPM) 2 compounds in gaseous mixture took place between components. Thermal decomposition of copper and yttrium β-diketonates was observed with temperature growth, along with reactions of interligand exchange. Molecular forms of Y(DPM) 2 , Y(DPM)(AA), Cu(DPM) 2 and Cu(DPM)(AA) were the most thermally stable at that
Critical current properties in superconducting melt processed Y-Ba-Cu-O

International Nuclear Information System (INIS)

Matsushita, Teruo

1993-01-01

The critical current density in bulk superconducting Y-Ba-Cu-O has been remarkably improved by employing the so-called melt process. However, its value is still far below those reported in single-crystalline thin films. Important key factors that determine the critical current density are the flux pinning mechanism and defective structures such as cracks or weak links. In this article, these factors in melt-processed Y-Ba-Cu-O are argued from various measurements of the critical current density on the microstructure dependence, the magnetic field dependence, the temperature dependence, the history effect, the longitudinal field effect and the imaginary ac susceptibility. As for the pinning mechanism, it is concluded that the dominant pinning centers in the high temperature region around 77 K are normal 211 (Y 2 BaCuO 5 ) particles, while small defects such as lattice defects or oxygen deficiencies seem to be dominant in the lower temperature region. It is suggested that much finer normal particles should be introduced in order to improve the critical current density especially at higher temperatures. From the rapid decrease of the critical current density with elevating temperature below 30 K, some kind of weak links are considered to still remain in these materials. However, the observed critical current density did not depend on the history of application of the magnetic field and a large enhancement of the critical current density was observed in the longitudinal field geometry at 4.2 K. These results suggest that the weak links in these materials are of much different kind from those at large angle grain boundaries in sintered polycrystalline materials. From the X-ray diffraction measurements, a domain structure of a mean domain size of about 100 μm was found. These domain boundaries may cause weak links in melt-processed Y-Ba-Cu-O. It is also shown that the typical size of channels of flowing current can be obtained by the imaginary ac susceptibility
The effect of the sulfur concentration on the phase transformation from the mixed CuO-Bi{sub 2}O{sub 3} system to Cu{sub 3}BiS{sub 3} during the sulfurization process

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lijian; Jin, Xin; Yuan, Chenchen; Jiang, Guoshun; Liu, Weifeng, E-mail: liuwf@ustc.edu.cn; Zhu, Changfei, E-mail: cfzhu@ustc.edu.cn

2016-12-15

Highlights: • Cu{sub 3}BiS{sub 3} thin films were creatively fabricated by sulfurizing metal oxide precursor. • The phase transformation mechanism during the sulfurization process was studied. • The reason why the excess S restrained the formation of Cu{sub 3}BiS{sub 3} was discussed. • The effect of temperature on film morphology and bandgap was studied. - Abstract: The ternary semiconductor Cu{sub 3}BiS{sub 3}, as a promising light-absorber material for thin film solar cells, was creatively synthesized by sulfurizing the mixed metal oxides precursor film deposited by spin-coating chemical solution method. Two kinds of sulfurization techniques were introduced to study the effect of the sulfur concentration on the phase formation for the pure Cu{sub 3}BiS{sub 3}. It was found that Cu-poor S-rich phases such as Cu{sub 3}Bi{sub 3}S{sub 7} and Cu{sub 4}Bi{sub 4}S{sub 9} were easily generated at high S concentration and then can transform to Cu{sub 3}BiS{sub 3} phase by a simple desulphurization process, which means the sulfur concentration had a significant influence on the formation of Cu{sub 3}BiS{sub 3} during the sulfurization process. The probable transformation mechanism from the mixed metal oxides to the pure Cu{sub 3}BiS{sub 3} phase during the sulfurization process was studied in detail through the XRD analysis and thermodynamic calculation. In addition, the electrical properties were characterized by Hall measurement and the effects of sulfurization temperature on the phase transformation, morphology and optical band gap of the absorber layer were also studied in detail.
TPD IR studies of CO desorption from zeolites CuY and CuX

Science.gov (United States)

Datka, Jerzy; Kozyra, Paweł

2005-06-01

The desorption of CO from zeolites CuY and CuX was followed by TPD-IR method. This is a combination of temperature programmed desorption and IR spectroscopy. In this method, the status of activated zeolite (before adsorption), the process of adsorption, and the status of adsorbed molecules can be followed by IR spectroscopy, and the process of desorption (with linear temperature increase) can be followed both by IR spectroscopy and by mass spectrometry. IR spectra have shown two kinds of Cu + sites in both CuY and CuX. Low frequency (l.f.) band (2140 cm -1 in CuY and 2130 cm -1 in CuX) of adsorbed CO represents Cu + sites for which π back donation is stronger and σ donation is weaker whereas high frequency h.f. band (2160 cm -1 in CuY and 2155 cm -1 in CuX) represent Cu + sites for which π back donation is weaker and σ donation is stronger. The TPD-IR experiments evidenced that the Cu + sites represented by l.f. band bond CO more weakly than those represented by h.f. one, indicating that σ donation has more important impact to the strength of Cu +-CO bonding. On the contrary, π back donation has bigger contribution to the activation of adsorbed molecules.
Room temperature Cu-Cu direct bonding using surface activated bonding method

International Nuclear Information System (INIS)

Kim, T.H.; Howlader, M.M.R.; Itoh, T.; Suga, T.

2003-01-01

Thin copper (Cu) films of 80 nm thickness deposited on a diffusion barrier layered 8 in. silicon wafers were directly bonded at room temperature using the surface activated bonding method. A low energy Ar ion beam of 40-100 eV was used to activate the Cu surface prior to bonding. Contacting two surface-activated wafers enables successful Cu-Cu direct bonding. The bonding process was carried out under an ultrahigh vacuum condition. No thermal annealing was required to increase the bonding strength since the bonded interface was strong enough at room temperature. The chemical constitution of the Cu surface was examined by Auger electron spectroscope. It was observed that carbon-based contaminations and native oxides on copper surface were effectively removed by Ar ion beam irradiation for 60 s without any wet cleaning processes. An atomic force microscope study shows that the Ar ion beam process causes no surface roughness degradation. Tensile test results show that high bonding strength equivalent to bulk material is achieved at room temperature. The cross-sectional transmission electron microscope observations reveal the presence of void-free bonding interface without intermediate layer at the bonded Cu surfaces
Process design of a hydrogen production plant from natural gas with CO2 capture based on a novel Ca/Cu chemical loop

International Nuclear Information System (INIS)

Martínez, I.; Romano, M.C.; Fernández, J.R.; Chiesa, P.; Murillo, R.; Abanades, J.C.

2014-01-01

Highlights: • Process design of a H 2 production plant based on a novel Ca/Cu looping process is presented. • CuO reduction with syngas provides energy for CaCO 3 calcination. • The effect of operating conditions on plant performance indexes is analysed. • Carbon capture efficiencies of around 94% are obtained. • Around 6% points of equivalent H 2 efficiency improvement on conventional reforming. - Abstract: A detailed and comprehensive design of a H 2 production plant based on a novel Ca/Cu chemical looping process is presented in this work. This H 2 production process is based on the sorption-enhanced reforming concept using natural gas together with a CaO/CaCO 3 chemical loop. A second Cu/CuO loop is incorporated to supply energy for the calcination of the CaCO 3 via the reduction of CuO with a fuel gas. A comprehensive energy integration description of the different gas streams available in the plant is provided to allow a thermodynamic assessment of the process and to highlight its advantages and drawbacks. Hydrogen equivalent efficiencies of up to 77% are feasible with this novel Ca/Cu looping process, using an active reforming catalyst based on Pt, high oxidation temperatures and moderate gas velocities in the fixed bed system, which are around 6% points above the efficiency of a reference H 2 production plant based on conventional steam reforming including CO 2 capture with MDEA. Non-converted carbon compounds in the reforming stage are removed as CO 2 in the calcination stage of the Ca/Cu looping process, which will be compressed and sent for storage. Carbon capture efficiencies of around 94% can be obtained with this Ca/Cu looping process, which are significantly higher than those obtained in the reference plant that uses MDEA absorption (around 85%). Additional advantages, such as its compact design and the use of cheaper materials compared to other commercial processes for H 2 production with CO 2 capture, confirm the potential of the Ca/Cu
Recurrent intergrowths in the topotactic reduction process of LaBaCuCoO5.2.

Science.gov (United States)

Ruiz-González, Luisa; Boulahya, Khalid; Parras, Marina; Alonso, José; González-Calbet, José M

2002-12-16

A new perovskite-related oxide with the LaBaCuCoO5.2 composition has been stabilised. Its structure can be described as formed by the recurrent intergrowth of two alternating blocks of YBaCuFeO5 (2ac, i.e., two-fold perovskite superlattice) and YBa2Fe3O8 (3ac) structural types. From the starting material LaBaCuCoO5.2-delta (delta = 0), the rigorous control of the oxygen content has allowed the stabilisation of three new five fold perovskite-related superstructures with the compositions delta = 0.4, 0.8 and 1.1, which can also be described as recurrent intergrowths of two blocks showing 2ac and 3ac periodicity. The reduction process takes place through the 3ac periodic blocks, when 0 topotactic reaction, since their basic structure is kept through the reduction process.
Characterization of process-induced damage in Cu/low-k interconnect structure by microscopic infrared spectroscopy with polarized infrared light

Energy Technology Data Exchange (ETDEWEB)

Seki, Hirofumi, E-mail: Hirofumi-Seki@trc.toray.co.jp; Hashimoto, Hideki [Toray Research Center, Inc., 3-3-7 Sonoyama, Otsu, Shiga 520-8567 (Japan); Ozaki, Yukihiro [Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1, Gakuen, Sanda, Hyogo 669-1337 (Japan)

2016-09-07

Microscopic Fourier-transform infrared (FT-IR) spectra are measured for a Cu/low-k interconnect structure using polarized IR light for different widths of low-k spaces and Cu lines, and for different heights of Cu lines, on Si substrates. Although the widths of the Cu line and the low-k space are 70 nm each, considerably smaller than the wavelength of the IR light, the FT-IR spectra of the low-k film were obtained for the Cu/low-k interconnect structure. A suitable method was established for measuring the process-induced damage in a low-k film that was not detected by the TEM-EELS (Transmission Electron Microscope-Electron Energy-Loss Spectroscopy) using microscopic IR polarized light. Based on the IR results, it was presumed that the FT-IR spectra mainly reflect the structural changes in the sidewalls of the low-k films for Cu/low-k interconnect structures, and the mechanism of generating process-induced damage involves the generation of Si-OH groups in the low-k film when the Si-CH{sub 3} bonds break during the fabrication processes. The Si-OH groups attract moisture and the OH peak intensity increases. It was concluded that the increase in the OH groups in the low-k film is a sensitive indicator of low-k damage. We achieved the characterization of the process-induced damage that was not detected by the TEM-EELS and speculated that the proposed method is applicable to interconnects with line and space widths of 70 nm/70 nm and on shorter scales of leading edge devices. The location of process-induced damage and its mechanism for the Cu/low-k interconnect structure were revealed via the measurement method.
Stress/strain characteristics of Cu alloy sheath in situ processed MgB2 superconducting wires

International Nuclear Information System (INIS)

Katagiri, Kazumune; Kasaba, Koichi; Shoji, Yoshitaka

2005-01-01

The mechanical properties of copper and copper alloy (Cu-Zr, Cu-Be and Cu-Cr) sheath in situ PIT-processed MgB 2 superconducting wires were studied at room temperature (RT) and 4.2 K. The effects of stress-strain on the critical current (I c ) of the wires have also been studied at 4.2 K and in magnetic fields up to 5 T. It has been clarified that alloying the Cu sheath significantly increases the yield and flow stresses of the wires at both RT and 4.2 K. The 0.5% flow stresses of the Cu alloy sheath wire were 147-237 MPa, whereas that of Cu was 55 MPa. At RT, serration corresponding to multiple cracking was observed around a strain of 0.4% and the stress-strain curves saturated beyond that point. The strain dependence of I c prior to the critical strain (ε irr ) was different depending on the magnetic field; being almost constant at 2 T and increasing with strain at 5 T. The I c decreased beyond ε irr , which is much larger for Cu alloy sheath wires as compared to Cu sheath wire. This is due to the difference in the residual compressive strain in the MgB 2 core during cooling from the heat-treatment temperature to 4.2 K, which is determined through relaxation by yielding in the sheath materials. The transverse compression tests revealed that the I c of the Cu alloy sheath wire did not degrade up to 314 MPa, which is also higher than that of Cu sheath wire. (author)
Uncovering the Problem-Solving Process: Cued Retrospective Reporting Versus Concurrent and Retrospective Reporting

NARCIS (Netherlands)

Van Gog, Tamara; Paas, Fred; Van Merriënboer, Jeroen; Witte, P.

2007-01-01

This study investigated the amounts of problem-solving process information ("action," "why," "how," and "metacognitive") elicited by means of concurrent, retrospective, and cued retrospective reporting. In a within-participants design, 26 participants completed electrical circuit troubleshooting
Based on Cu as framework constructed nanoporous CuO/Cu composites by a dealloy method for sodium-ion battery anode

Science.gov (United States)

Zheng, Tian; Li, Guangda; Li, Deming; Meng, Xiangeng

2018-05-01

Nanoporous CuO/Cu composites with a continuous channel structure were fabricated through a corroding Cu-Al alloy process. The width of the continuous channels was about 20 50 nm. Nanoporous structure could effectively sustain the volume expansion during the Na+ insertion/extraction process and shorten the Na+ diffusion length as well, which thus helps improve the Na+ storage performance. Moreover, the nanoporous structure can improve the contact area between the electrolyte and the electrode, leading to an increment in the number of Na+ insertion/extraction sites. When used as the anode for sodium-ion batteries, the CuO/Cu exhibited an initial capacity of 580 mAh g-1, and the capacity is maintained at 200 mAh g-1 after 200 cycles at a current density of 500 mA g-1.

In situ surface X-ray diffraction studies of the copper-electrolyte interface. Atomic structure and homoepitaxial grwoth

Energy Technology Data Exchange (ETDEWEB)

Golks, Frederik

2011-05-19

Copper electrodeposition is the predominantly used technique for on-chip wiring in the fabrication of ultra-large scale integrated (ULSI) microchips. In this 'damascene copper electroplating' process, multicomponent electrolytes containing organic additives realize void-free filling of trenches with high aspect ratio ('superconformal deposition'). Despite manifold studies, motivated by the continuous trend to shrink wiring dimensions and thus the demand of optimized plating baths, detailed knowledge on the growth mechanism - in presence and absence of additives - is still lacking. Using a recently developed hanging meniscus X-ray transmission cell, brilliant synchrotron x-rays and a fast, one-dimensional detector system, unique real-time in situ surface X-ray diffraction studies of copper electrodeposition were performed under realistic reaction conditions, approaching rates of technological relevance. Preparatory measurements of the electrochemical dissolution of Au(001) in chloride-containing electrolyte demonstrated the capability of this powerful technique, specifically the possibility to follow atomic-scale deposition or dissolution processes with a time resolution down to five milliseconds. The electrochemical as well as structural characterization of the Cu(001)- and Cu(111)-electrolyte interfaces provided detailed insight into the complex atomic-scale structures in presence of specifically adsorbed chloride on these surfaces. The interface of Cu(001) in chloride-containing electrolyte exhibits a continuous surface phase transition of a disordered Cl adlayer to a c(2 x 2) Cl adlayer with increasing potential. The latter was found to induce a small vertical corrugation of substrate atoms, which can be ascribed to lattice relaxations induced by the presence of coadsorbed water molecules and cations in the outer part of the electrochemical double layer. The study of the specific adsorption of chloride on Cu(111) from acidic aqueous
In situ surface X-ray diffraction studies of the copper-electrolyte interface. Atomic structure and homoepitaxial grwoth

Energy Technology Data Exchange (ETDEWEB)

Golks, Frederik

2011-05-19

Copper electrodeposition is the predominantly used technique for on-chip wiring in the fabrication of ultra-large scale integrated (ULSI) microchips. In this 'damascene copper electroplating' process, multicomponent electrolytes containing organic additives realize void-free filling of trenches with high aspect ratio ('superconformal deposition'). Despite manifold studies, motivated by the continuous trend to shrink wiring dimensions and thus the demand of optimized plating baths, detailed knowledge on the growth mechanism - in presence and absence of additives - is still lacking. Using a recently developed hanging meniscus X-ray transmission cell, brilliant synchrotron x-rays and a fast, one-dimensional detector system, unique real-time in situ surface X-ray diffraction studies of copper electrodeposition were performed under realistic reaction conditions, approaching rates of technological relevance. Preparatory measurements of the electrochemical dissolution of Au(001) in chloride-containing electrolyte demonstrated the capability of this powerful technique, specifically the possibility to follow atomic-scale deposition or dissolution processes with a time resolution down to five milliseconds. The electrochemical as well as structural characterization of the Cu(001)- and Cu(111)-electrolyte interfaces provided detailed insight into the complex atomic-scale structures in presence of specifically adsorbed chloride on these surfaces. The interface of Cu(001) in chloride-containing electrolyte exhibits a continuous surface phase transition of a disordered Cl adlayer to a c(2 x 2) Cl adlayer with increasing potential. The latter was found to induce a small vertical corrugation of substrate atoms, which can be ascribed to lattice relaxations induced by the presence of coadsorbed water molecules and cations in the outer part of the electrochemical double layer. The study of the specific adsorption of chloride on Cu(111) from acidic aqueous electrolyte revealed a
Influences on Distribution of Solute Atoms in Cu-8Fe Alloy Solidification Process Under Rotating Magnetic Field

Science.gov (United States)

Zou, Jin; Zhai, Qi-Jie; Liu, Fang-Yu; Liu, Ke-Ming; Lu, De-Ping

2018-05-01

A rotating magnetic field (RMF) was applied in the solidification process of Cu-8Fe alloy. Focus on the mechanism of RMF on the solid solution Fe(Cu) atoms in Cu-8Fe alloy, the influences of RMF on solidification structure, solute distribution, and material properties were discussed. Results show that the solidification behavior of Cu-Fe alloy have influenced through the change of temperature and solute fields in the presence of an applied RMF. The Fe dendrites were refined and transformed to rosettes or spherical grains under forced convection. The solute distribution in Cu-rich phase and Fe-rich phase were changed because of the variation of the supercooling degree and the solidification rate. Further, the variation in solute distribution was impacted the strengthening mechanism and conductive mechanism of the material.
Neutron-rich isotopes around the r-process 'waiting-point' nuclei 2979Cu50 and 3080Zn50

International Nuclear Information System (INIS)

Kratz, K.L.; Gabelmann, H.; Pfeiffer, B.; Woehr, A.

1991-01-01

Beta-decay half-lives (T 1/2 ) and delayed-neutron emission probabilities (P n ) of very neutron-rich Cu to As nuclei have been measured, among them the new isotopes 77 Cu 48 , 79 Cu 50 , 81 Zn 51 and 84 Ga 53 . With the T 1/2 and P n -values of now four N≅50 'waiting-point' nuclei known, our hypothesis that the r-process has attained a local β-flow equilibrium around A≅80 is further strengthened. (orig.)
Influence of Oxygen Partial Pressure during Processing on the Thermoelectric Properties of Aerosol-Deposited CuFeO₂.

Science.gov (United States)

Stöcker, Thomas; Exner, Jörg; Schubert, Michael; Streibl, Maximilian; Moos, Ralf

2016-03-24

In the field of thermoelectric energy conversion, oxide materials show promising potential due to their good stability in oxidizing environments. Hence, the influence of oxygen partial pressure during synthesis on the thermoelectric properties of Cu-Delafossites at high temperatures was investigated in this study. For these purposes, CuFeO₂ powders were synthetized using a conventional mixed-oxide technique. X-ray diffraction (XRD) studies were conducted to determine the crystal structures of the delafossites associated with the oxygen content during the synthesis. Out of these powders, films with a thickness of about 25 µm were prepared by the relatively new aerosol-deposition (AD) coating technique. It is based on a room temperature impact consolidation process (RTIC) to deposit dense solid films of ceramic materials on various substrates without using a high-temperature step during the coating process. On these dense CuFeO₂ films deposited on alumina substrates with electrode structures, the Seebeck coefficient and the electrical conductivity were measured as a function of temperature and oxygen partial pressure. We compared the thermoelectric properties of both standard processed and aerosol deposited CuFeO₂ up to 900 °C and investigated the influence of oxygen partial pressure on the electrical conductivity, on the Seebeck coefficient and on the high temperature stability of CuFeO₂. These studies may not only help to improve the thermoelectric material in the high-temperature case, but may also serve as an initial basis to establish a defect chemical model.
The facile synthesis of a chitosan Cu(II) complex by solution plasma process and evaluation of their antioxidant activities.

Science.gov (United States)

Ma, Fengming; Li, Pu; Zhang, Baiqing; Wang, Zhenyu

2017-10-01

Synthesis of chitosan-Cu(II) complex by solution plasma process (SPP) irradiation was investigated. The effects of the distance between the electrodes, initial Cu(II) concentration, and initial pH on the Cu(II) adsorption capacity were evaluated. The results showed that narrower distance between the electrodes, higher initial Cu(II) concentration and higher initial pH (at pHchitosan-Cu(II) complex by ultraviolet-visible (UV-vis), fourier transform infrared (FT-IR) and electron spin resonance (ESR) spectroscopy revealed that the main structure of chitosan was not changed after irradiation. Thermogravimetry (TG) analysis indicated that Cu(II) ions were well incorporated into the chitosan. The antioxidant activity of the chitosan-Cu(II) complex was evaluated by DPPH, ABTS, and reducing power assays. The chitosan-Cu(II) complex exhibited greater antioxidant activity than the original chitosan. Thus, SPP could be used for preparation of chitosan-Cu(II) complexes. Copyright © 2017. Published by Elsevier B.V.
Structure evolution during the cooling and coalesced cooling processes of Cu-Co bimetallic clusters

International Nuclear Information System (INIS)

Li Guojian; Wang Qiang; Li Donggang; Lue Xiao; He Jicheng

2008-01-01

Constant-temperature molecular dynamics with general EAM was employed to study the structure evolutions during the cooling and coalesced cooling processes of Cu-Co bimetallic clusters. It shows that the desired particle morphologies and structures can be obtained by controlling the composition and distribution of hetero atoms during synthesis process
Solution-processed inorganic copper(I) thiocyanate (CuSCN) hole transporting layers for efficient p–i–n perovskite solar cells

KAUST Repository

Zhao, Kui

2015-08-27

CuSCN is a highly transparent, highly stable, low cost and easy to solution process HTL that is proposed as a low cost replacement to existing organic and inorganic metal oxide hole transporting materials. Here, we demonstrate hybrid organic-inorganic perovskite-based p-i-n planar heterojunction solar cells using a solution-processed copper(I) thiocyanate (CuSCN) bottom hole transporting layer (HTL). CuSCN, with its high workfunction, increases the open circuit voltage (Voc) by 0.23 V to 1.06 V as compared with devices based on the well-known poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (0.83 V), resulting in a superior power conversion efficiency (PCE) of 10.8% without any notable hysteresis. Photoluminescence measurements suggest a similar efficiency of charge transfer at HTL/perovskite interface as PEDOT:PSS. However, we observe more efficient light harvesting in the presence of CuSCN at shorter wavelengths despite PEDOT:PSS being more transparent. Further investigation of the microstructure and morphology reveals differences in the crystallographic texture of the polycrystalline perovskite film, suggesting somewhat modified perovskite growth on the surface of CuSCN. The successful demonstration of the solution-processed inorganic HTL using simple and low temperature processing routes bodes well for the development of reliable and efficient flexible p-i-n perovskite modules or for integration as a front cell in hybrid tandem solar cells.
Atomistic scale nanoscratching behavior of monocrystalline Cu influenced by water film in CMP process

Science.gov (United States)

Shi, Junqin; Chen, Juan; Fang, Liang; Sun, Kun; Sun, Jiapeng; Han, Jing

2018-03-01

The effect of water film on the nanoscratching behavior of monocrystalline Cu was studied by molecular dynamics (MD) simulation. The results indicate that the friction force acting on abrasive particle increases due to the resistance of water film accumulating ahead of particle, but the water film with lubrication decreases friction force acting on Cu surface. The accumulation of water molecules around particle causes the anisotropy of ridge and the surface damage around the groove, and the water molecules remaining in the groove lead to the non-regular groove structure. The dislocation evolution displays the re-organization of the dislocation network in the nanoscratching process. The evaluation of removal efficiency shows the number of removed Cu atoms decreases with water film thickness. It is considered that an appropriate rather than a high removal efficiency should be adopted to evaluate the polishing process in real (chemical mechanical polishing) CMP. These results are helpful to reveal the polishing mechanism under the effect of water film from physical perspective, which benefits the development of ultra-precision manufacture and miniaturized components, as well as the innovation of CMP technology.
Cu/Cu2O/CuO nanoparticles: Novel synthesis by exploding wire technique and extensive characterization

Science.gov (United States)

Sahai, Anshuman; Goswami, Navendu; Kaushik, S. D.; Tripathi, Shilpa

2016-12-01

In this article, we explore potential of Exploding Wire Technique (EWT) to synthesize the copper nanoparticles using the copper metal in a plate and wire geometry. Rietveld refinement of X-ray diffraction (XRD) pattern of prepared material indicates presence of mixed phases of copper (Cu) and copper oxide (Cu2O). Agglomerates of copper and copper oxide comprised of ∼20 nm average size nanoparticles observed through high resolution transmission electron microscope (HRTEM) and energy dispersive x-ray (EDX) spectroscopy. Micro-Raman (μR) and Fourier transform infrared (FTIR) spectroscopies of prepared nanoparticles reveal existence of additional minority CuO phase, not determined earlier through XRD and TEM analysis. μR investigations vividly reveal cubic Cu2O and monoclinic CuO phases based on the difference of space group symmetries. In good agreement with μRaman analysis, FTIR stretching modes corresponding to Cu2-O and Cu-O were also distinguished. Investigations of μR and FTIR vibrational modes are in accordance and affirm concurrence of CuO phases besides predominant Cu and Cu2O phase. Quantum confinement effects along with increase of band gaps for direct and indirect optical transitions of Cu/Cu2O/CuO nanoparticles are reflected through UV-vis (UV-vis) spectroscopy. Photoluminescence (PL) spectroscopy spots the electronic levels of each phase and optical transitions processes occurring therein. Iterative X-ray photoelectron spectroscopy (XPS) fitting of core level spectra of Cu (2p3/2) and O (1s), divulges presence of Cu2+ and Cu+ in the lattice with an interesting evidence of O deficiency in the lattice structure and surface adsorption. Magnetic analysis illustrates that the prepared nanomaterial demonstrates ferromagnetic behaviour at room temperature.
Low-Temperature Cu-Cu Bonding Using Silver Nanoparticles Fabricated by Physical Vapor Deposition

Science.gov (United States)

Wu, Zijian; Cai, Jian; Wang, Junqiang; Geng, Zhiting; Wang, Qian

2018-02-01

Silver nanoparticles (Ag NPs) fabricated by physical vapor deposition (PVD) were introduced in Cu-Cu bonding as surface modification layer. The bonding structure consisted of a Ti adhesive/barrier layer and a Cu substrate layer was fabricated on the silicon wafer. Ag NPs were deposited on the Cu surface by magnetron sputtering in a high-pressure environment and a loose structure with NPs was obtained. Shear tests were performed after bonding, and the influences of PVD pressure, bonding pressure, bonding temperature and annealing time on shear strength were assessed. Cu-Cu bonding with Ag NPs was accomplished at 200°C for 3 min under the pressure of 30 MPa without a post-annealing process, and the average bonding strength of 13.99 MPa was reached. According to cross-sectional observations, a void-free bonding interface with an Ag film thickness of around 20 nm was achieved. These results demonstrated that a reliable low-temperature short-time Cu-Cu bonding was realized by the sintering process of Ag NPs between the bonding pairs, which indicated that this bonding method could be a potential candidate for future ultra-fine pitch 3D integration.
Advanced Precursor Reaction Processing for Cu(InGa)(SeS)2 Solar Cells

Energy Technology Data Exchange (ETDEWEB)

Shafarman, William N. [Univ. of Delaware, Newark, DE (United States)

2015-10-12

This project “Advanced Precursor Reaction Processing for Cu(InGa)(SeS)2 Solar Cells”, completed by the Institute of Energy Conversion (IEC) at the University of Delaware in collaboration with the Department of Chemical Engineering at the University of Florida, developed the fundamental understanding and technology to increase module efficiency and improve the manufacturability of Cu(InGa)(SeS)2 films using the precursor reaction approach currently being developed by a number of companies. Key results included: (1) development of a three-step H2Se/Ar/H2S reaction process to control Ga distribution through the film and minimizes back contact MoSe2 formation; (2) Ag-alloying to improve precursor homogeneity by avoiding In phase agglomeration, faster reaction and improved adhesion to allow wider reaction process window; (3) addition of Sb, Bi, and Te interlayers at the Mo/precursor junction to produce more uniform precursor morphology and improve adhesion with reduced void formation in reacted films; (4) a precursor structure containing Se and a reaction process to reduce processing time to 5 minutes and eliminate H2Se usage, thereby increasing throughput and reducing costs. All these results were supported by detailed characterization of the film growth, reaction pathways, thermodynamic assessment and device behavior.
Mono-domain YBa2Cu3Oy superconductor fabrics prepared by an infiltration process

International Nuclear Information System (INIS)

Sudhakar Reddy, E.; Noudem, J.G.; Tarka, M.; Schmitz, G.J.

2000-01-01

A novel process for the fabrication of a new form of YBa 2 Cu 3 O y (123) superconducting material, with the dimensions of a thick film and the microstructure of a melt-textured single-domain bulk is described. The process allows the fabrication of 123 as a self-supporting fabric or as a thick film on various substrate materials. The process, which is generic and economical, uses commercially available Y 2 O 3 fabrics as a precursor material. The Y 2 O 3 cloth is infiltrated with barium cuprates and copper oxides from a liquid-phase source, then converted into Y 2 BaCuO 5 (211) phase and eventually to 123. The nucleation and growth of the 123 phase is controlled by seeding the cloth with an oriented heterogeneous MgO or Nd123 seed. Interesting application areas for the new form of the 123 mono-domain fabric are discussed. (author)
Initial crystallization and growth in melt processing of large-domain YBa2Cu3Ox for magnetic levitation

International Nuclear Information System (INIS)

Shi, D.

1994-10-01

Crystallization temperature in YBa 2 Cu 3 O x (123) during peritectic reaction has been studied by differential thermal analysis (DTA) and optical microscopy. It has been found that YBa 2 Cu 3 O x experiences partial melting near 1,010 C during heating while crystallization takes place at a much lower temperature range upon cooling indicating a delayed nucleation process. A series of experiments have been conducted to search for the initial crystallization temperature in the Y 2 BaCuO x + liquid phase field. The authors have found that the slow-cool period (1 C/h) for the 123 grain texturing can start at as low as 960 C. This novel processing has resulted in high-quality, large-domain, strongly pinned 123 magnetic levitators
An efficient synthesis of isocoumarins via a CuI catalyzed cascade reaction process

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

3-Alkyl isocoumarins are provided by CuI/amino acid-catalyzed Sonogashira coupling reaction of o-bromo benzoic acids and terminal alkynes and the subsequent additive cyclization. This cascade process allows synthesis of diverse isocoumarins by varying both coupling partners bearing a wide range of functional groups.
In-situ studies of the recrystallization process of CuInS2 thin films by energy dispersive X-ray diffraction

International Nuclear Information System (INIS)

Thomas, D.; Mainz, R.; Rodriguez-Alvarez, H.; Marsen, B.; Abou-Ras, D.; Klaus, M.; Genzel, Ch.; Schock, H.-W.

2011-01-01

Recrystallization processes during the sulfurization of CuInS 2 (CIS) thin films have been studied in-situ using energy dispersive X-ray diffraction (EDXRD) with synchrotron radiation. In order to observe the recrystallization isolated from other reactions occurring during film growth, Cu-poor, small grained CIS layers covered with CuS on top were heated in a vacuum chamber equipped with windows for synchrotron radiation in order to analyze the grain growth mechanism within the CIS layer. In-situ monitoring of the grain size based on diffraction line profile analysis of the CIS-112 reflection was utilized to interrupt the recrystallization process at different points. Ex-situ studies by electron backscatter diffraction (EBSD) and energy dispersive X-ray spectroscopy (EDX) performed on samples of intermediate recrystallization states reveal that during the heat treatment Cu and In interdiffuse inside the layer indicating the importance of the mobility of these two elements during CuInS 2 grain growth.
Fabrication and heat treatment of high strength Al-Cu-Mg alloy processed using selective laser melting

Science.gov (United States)

Zhang, Hu; Zhu, Haihong; Nie, Xiaojia; Qi, Ting; Hu, Zhiheng; Zeng, Xiaoyan

2016-04-01

The proposed paper illustrates the fabrication and heat treatment of high strength Al-Cu-Mg alloy produced by selective laser melting (SLM) process. Al-Cu-Mg alloy is one of the heat treatable aluminum alloys regarded as difficult to fusion weld. SLM is an additive manufacturing technique through which components are built by selectively melting powder layers with a focused laser beam. The process is characterized by short laser-powder interaction times and localized high heat input, which leads to steep thermal gradients, rapid solidification and fast cooling. In this research, 3D Al-Cu-Mg parts with relative high density of 99.8% are produced by SLM from gas atomized powders. Room temperature tensile tests reveal a remarkable mechanical behavior: the samples show yield and tensile strengths of about 276 MPa and 402 MPa, respectively, along with fracture strain of 6%. The effect of solution treatment on microstructure and related tensile properties is examined and the results demonstrate that the mechanical behavior of the SLMed Al-Cu-Mg samples can be greatly enhanced through proper heat treatment. After T4 solution treatment at 540°C, under the effect of precipitation strengthening, the tensile strength and the yield strength increase to 532 MPa and 338 MPa, respectively, and the elongation increases to 13%.
Cu/Cu{sub 2}O/CuO nanoparticles: Novel synthesis by exploding wire technique and extensive characterization

Energy Technology Data Exchange (ETDEWEB)

Sahai, Anshuman [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida 201307 (India); Goswami, Navendu, E-mail: navendugoswami@gmail.com [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida 201307 (India); Kaushik, S.D. [UGC-DAE-Consortium for Scientific Research Mumbai Centre, R5 Shed, BARC, Mumbai 400085 (India); Tripathi, Shilpa [UGC-DAE Consortium for Scientific Research, Indore, M.P. (India)

2016-12-30

Highlights: The salient features of this research article are following: • Mixed phase synthesis of Cu/Cu{sub 2}O/CuO nanoparticles prepared by Exploding Wire Technique (EWT). • Predominant Cu/Cu{sub 2}O phases along with minor CuO phase revealed through XRD, TEM, Raman, FTIR, UV–Visible and PL analyses. • XPS analysis provided direct evidences of Cu{sup 2+} and Cu{sup +} along with O deficiency for prepared nanoparticles. • Room temperature weak ferromagnetic behaviour was demonstrated for Cu/Cu{sub 2}O/CuO nanoparticles. - Abstract: In this article, we explore potential of Exploding Wire Technique (EWT) to synthesize the copper nanoparticles using the copper metal in a plate and wire geometry. Rietveld refinement of X-ray diffraction (XRD) pattern of prepared material indicates presence of mixed phases of copper (Cu) and copper oxide (Cu{sub 2}O). Agglomerates of copper and copper oxide comprised of ∼20 nm average size nanoparticles observed through high resolution transmission electron microscope (HRTEM) and energy dispersive x-ray (EDX) spectroscopy. Micro-Raman (μR) and Fourier transform infrared (FTIR) spectroscopies of prepared nanoparticles reveal existence of additional minority CuO phase, not determined earlier through XRD and TEM analysis. μR investigations vividly reveal cubic Cu{sub 2}O and monoclinic CuO phases based on the difference of space group symmetries. In good agreement with μRaman analysis, FTIR stretching modes corresponding to Cu{sub 2}-O and Cu-O were also distinguished. Investigations of μR and FTIR vibrational modes are in accordance and affirm concurrence of CuO phases besides predominant Cu and Cu{sub 2}O phase. Quantum confinement effects along with increase of band gaps for direct and indirect optical transitions of Cu/Cu{sub 2}O/CuO nanoparticles are reflected through UV–vis (UV–vis) spectroscopy. Photoluminescence (PL) spectroscopy spots the electronic levels of each phase and optical transitions processes
Episodic feeling-of-knowing accuracy and cued recall in the elderly: evidence for double dissociation involving executive functioning and processing speed.

Science.gov (United States)

Perrotin, Audrey; Isingrini, Michel; Souchay, Céline; Clarys, David; Taconnat, Laurence

2006-05-01

This research investigated adult age differences in a metamemory monitoring task-episodic feeling-of-knowing (FOK) and in an episodic memory task-cued recall. Executive functioning and processing speed were examined as mediators of these age differences. Young and elderly adults were administered an episodic FOK task, a cued recall task, executive tests and speed tests. Age-related decline was observed on all the measures. Correlation analyses revealed a pattern of double dissociation which indicates a specific relationship between executive score and FOK accuracy, and between speed score and cued recall. When executive functioning and processing speed were evaluated concurrently on FOK and cued recall variables, hierarchical regression analyses showed that executive score was a better mediator of age-related variance in FOK, and that speed score was the better mediator of age-related variance in cued recall.
In Situ Synthesis of Al-Si-Cu Alloy During Brazing Process and Mechanical Property of Brazing Joint

Directory of Open Access Journals (Sweden)

LONG Wei-min

2016-06-01

Full Text Available The Al-Si-Cu alloy system is considered to be a promising choice of filler metal for aluminium alloys brazing due to its high strength and low melting point. The greatest obstacle is its lack of plastic forming ability and being difficult to be processed by conventional methods. This disadvantage is ascribed to the considerable amount of brittle CuAl2 intermetallic compound which forms when alloy composition is around the ternary eutectic point. In order to overcome this deficiency, authors of this article proposed to synthesize Al-Si-Cu filler metal by using in situ synthesis method, and the structure and properties of brazing joints were studied. The results show that AlSi alloy is used as the wrap layer, and CuAl alloy is used as the powder core in the composite brazing wire, the two alloys have similar melting points. The machinability of the composite brazing wire is much superior to the traditional Al-Si-Cu filler metal. During the induction brazing of 3A21 alloy, when using AlSi-CuAl composite filler wire, AlSi and CuAl alloys melt almost simultaneously, then after short time holding, Al-Si-Cu braze filler is obtained, the brazing seam has uniform composition and good bonding interface, also, the shearing strength of the brazing joints is higher than the joint brazed by conventional Al-Si-Cu filler metal.

Depth Profile of Impurity Phase in Wide-Bandgap Cu(In1-x ,Ga x )Se2 Film Fabricated by Three-Stage Process

Science.gov (United States)

Wang, Shenghao; Nazuka, Takehiro; Hagiya, Hideki; Takabayashi, Yutaro; Ishizuka, Shogo; Shibata, Hajime; Niki, Shigeru; Islam, Muhammad M.; Akimoto, Katsuhiro; Sakurai, Takeaki

2018-02-01

For copper indium gallium selenide [Cu(In1-x ,Ga x )Se2, CIGS]-based solar cells, defect states or impurity phase always form due to both the multinary compositions of CIGS film and the difficulty of controlling the growth process, especially for high Ga concentration. To further improve device performance, it is important to understand such formation of impurity phase or defect states during fabrication. In the work presented herein, the formation mechanism of impurity phase Cu2-δ Se and its depth profile in CIGS film with high Ga content, in particular CuGaSe2 (i.e., CGS), were investigated by applying different growth conditions (i.e., normal three-stage process and two-cycle three-stage process). The results suggest that impurity phase Cu2-δ Se is distributed nonuniformly in the film because of lack of Ga diffusion. The formed Cu2-δ Se can be removed by etching the as-deposited CGS film with bromine-methanol solution, resulting in improved device performance.
Cu and Cu(Mn) films deposited layer-by-layer via surface-limited redox replacement and underpotential deposition

Energy Technology Data Exchange (ETDEWEB)

Fang, J.S., E-mail: jsfang@nfu.edu.tw [Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan (China); Sun, S.L. [Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan (China); Cheng, Y.L. [Department of Electrical Engineering, National Chi-Nan University, Nan-Tou 54561, Taiwan (China); Chen, G.S.; Chin, T.S. [Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan (China)

2016-02-28

Graphical abstract: - Abstract: The present paper reports Cu and Cu(Mn) films prepared layer-by-layer using an electrochemical atomic layer deposition (ECALD) method. The structure and properties of the films were investigated to elucidate their suitability as Cu interconnects for microelectronics. Previous studies have used primarily a vacuum-based atomic layer deposition to form a Cu metallized film. Herein, an entirely wet chemical process was used to fabricate a Cu film using the ECALD process by combining underpotential deposition (UPD) and surface-limited redox replacement (SLRR). The experimental results indicated that an inadequate UPD of Pb affected the subsequent SLRR of Cu and lead to the formation of PbSO{sub 4}. A mechanism is proposed to explain the results. Layer-by-layer deposition of Cu(Mn) films was successfully performed by alternating the deposition cycle-ratios of SLRR-Cu and UPD-Mn. The proposed self-limiting growth method offers a layer-by-layer wet chemistry-based deposition capability for fabricating Cu interconnects.
Electroreflectance of CuInS{sub 2}-solar cells for the optimization of the process parameters during the absorbers production process; Elektroreflexion an CuInS{sub 2}-Solarzellen im Hinblick auf die Optimierung der Prozessparameter bei der Absorber-Herstellung

Energy Technology Data Exchange (ETDEWEB)

Henninger, R.

2002-07-01

CuInS{sub 2} thin film solar cells were prepared by a new sequential process. The quality of these layers and the conversion efficiency of the solar cells depends on the process parameters of the sequential process. Electroreflectance measurements are used to characterize these solar cells. This method is suitable to measure optical properties like band gap energy and to detect secondary phases in the vicinity of the heterojunction and defects in the semiconductor. Electroreflectance measurements of the thin film solar cells shows clearly a dependence of film growth from the process parameters copper to indium ratio and sulfurization temperature. From the correlation of electroreflectance results with photoluminescence, X-ray-diffraction and external quantum efficiency measurements a model of film growth was derived. Solar cells made from optimized CuInS{sub 2} films reach an active area efficiency of 12,5%. This is the best efficiency reported so far for this type of solar cell. (orig.) [German] Mit einem neuen sequentiellen Verfahren wurden CuInS{sub 2}-Duennfilme fuer die Solarzellen-Anwendung hergestellt. Die Qualitaet dieser Schichten und damit der Solarzellenwirkungsgrad haengen von den Prozessparametern des sequentiellen Prozesses ab. Elektroreflexion wurde als Messverfahren zur Charakterisierung der fertigen Solarzellen eingesetzt. Dieses Verfahren ist geeignet um optische Eigenschaften, wie die Bandlueckenenergie, zu bestimmen und Fremdphasen in der Naehe des pn-Ueberganges sowie Defekte im Halbleiter nachzuweisen. In Elektroreflexionsmessungen an den hergestellten Duennfilmsolarzellen zeigte sich deutlich eine Abhaengigkeit des Schichtwachstums von den Prozessparametern Kupfer-Indium-Verhaeltnis und Sulfurisierungstemperatur. Aus der Korrelation der Elektroreflexionsergebnisse mit Photolumineszenz-, Roentgenbeugungs- und Quantenausbeutemessungen wurde ein Modell zur Schichtbildung von CuInS{sub 2} abgeleitet. Solarzellen aus optimierten CuInS{sub 2
CH{sub 4} dehydrogenation on Cu(1 1 1), Cu@Cu(1 1 1), Rh@Cu(1 1 1) and RhCu(1 1 1) surfaces: A comparison studies of catalytic activity

Energy Technology Data Exchange (ETDEWEB)

Zhang, Riguang; Duan, Tian [Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Ling, Lixia [Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Research Institute of Special Chemicals, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Wang, Baojun, E-mail: wangbaojun@tyut.edu.cn [Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China)

2015-06-30

Highlights: • Adsorbed Rh atom on Cu catalyst exhibits better catalytic activity for CH{sub 4} dehydrogenation. • The adsorbed Rh atom is the reaction active center for CH{sub 4} dehydrogenation. • The morphology of Cu substrate has negligible effect on CH{sub 4} dehydrogenation. - Abstract: In the CVD growth of graphene, the reaction barriers of the dehydrogenation for hydrocarbon molecules directly decide the graphene CVD growth temperature. In this study, density functional theory method has been employed to comparatively probe into CH{sub 4} dehydrogenation on four types of Cu(1 1 1) surface, including the flat Cu(1 1 1) surface (labeled as Cu(1 1 1)) and the Cu(1 1 1) surface with one surface Cu atom substituted by one Rh atom (labeled as RhCu(1 1 1)), as well as the Cu(1 1 1) surface with one Cu or Rh adatom (labeled as Cu@Cu(1 1 1) and Rh@Cu(1 1 1), respectively). Our results show that the highest barrier of the whole CH{sub 4} dehydrogenation process is remarkably reduced from 448.7 and 418.4 kJ mol{sup −1} on the flat Cu(1 1 1) and Cu@Cu(1 1 1) surfaces to 258.9 kJ mol{sup −1} on RhCu(1 1 1) surface, and to 180.0 kJ mol{sup −1} on Rh@Cu(1 1 1) surface, indicating that the adsorbed or substituted Rh atom on Cu catalyst can exhibit better catalytic activity for CH{sub 4} complete dehydrogenation; meanwhile, since the differences for the highest barrier between Cu@Cu(1 1 1) and Cu(1 1 1) surfaces are smaller, the catalytic behaviors of Cu@Cu(1 1 1) surface are very close to the flat Cu(1 1 1) surface, suggesting that the morphology of Cu substrate does not obviously affect the dehydrogenation of CH{sub 4}, which accords with the reported experimental observations. As a result, the adsorbed or substituted Rh atom on Cu catalyst exhibit a better catalytic activity for CH{sub 4} dehydrogenation compared to the pure Cu catalyst, especially on Rh-adsorbed Cu catalyst, we can conclude that the potential of synthesizing high-quality graphene with the
Electric field-induced hole transport in copper(i) thiocyanate (CuSCN) thin-films processed from solution at room temperature

KAUST Repository

Pattanasattayavong, Pichaya; Ndjawa, Guy Olivier Ngongang; Zhao, Kui; Chou, Kang Wei; Yaacobi-Gross, Nir; O'Regan, Brian C.; Amassian, Aram; Anthopoulos, Thomas D.

2013-01-01

The optical, structural and charge transport properties of solution-processed films of copper(i) thiocyanate (CuSCN) are investigated in this work. As-processed CuSCN films of ∼20 nm in thickness are found to be nano-crystalline, highly transparent and exhibit intrinsic hole transporting characteristics with a maximum field-effect mobility in the range of 0.01-0.1 cm2 V-1 s-1. © 2013 The Royal Society of Chemistry.
Microstructure and mechanical properties of Cu/SiC metal matrix composite fabricated via friction stir processing

International Nuclear Information System (INIS)

Akramifard, H.R.; Shamanian, M.; Sabbaghian, M.; Esmailzadeh, M.

2014-01-01

Highlights: • Designing a net hole was effective to achieve uniform distribution SiC particles and prevent agglomeration of them. • SZ has fine and equiaxed grains and distribution of SiC particles in the matrix is almost uniform. • No intermetallic compound was formed after FSP. • In comparison to pure Cu, Cu/SiC composite shows higher hardness and better wear behavior. - Abstract: In the present investigation, pure Cu sheets were reinforced with 25 μm SiC particles to fabricate a composite surface layer by friction stir processing (FSP). In order to improve distribution of reinforcing SiC particles, a net of holes were designed by drill on the surface of pure Cu sheet. For evaluation of microstructure, Optical Microscope (OM) and Scanning Electron Microscope (SEM) were used. Microstructural observation confirmed fine and equiaxed grains in the stir zone (SZ) and showed that SiC particles act as heterogeneous nucleation sites in the dynamic recrystallization of Cu grains. Moreover, agglomeration of particles was not observed and fine particles had a good distribution in SZ. In the SEM micrographs, porosities were detected as microstructure defects. Microhardness measurements showed that surface hardness was two times as high as that of substrate. The rotational wear tests demonstrated that use of SiC particles enhanced wear resistance and increased average friction coefficient of pure Cu. No intermetallic compound was found in Cu/SiC composite as revealed by XRD analysis
The defect structures and mechanical properties of Cu and Cu–Al alloys processed by split Hopkinson pressure bar

International Nuclear Information System (INIS)

Tao, Jingmei; Yang, Kai; Xiong, Haiwu; Wu, Xiaoxiang; Zhu, Xinkun; Wen, Cuie

2013-01-01

Pure Cu, Cu-5 at%Al, Cu-10 at%Al and Cu-15 at%Al with different stacking fault energy (SFE) of 78, 37, 7 and 5 mJ/m 2 , respectively, were processed through split Hopkinson pressure bar (SHPB) with the strain rate of 10 3 /sec. The influence of high strain rate on the evolution of microstructures and mechanical properties of Cu and Cu–Al alloys was investigated. X-ray diffraction measurements indicate that, the microstructures of Cu and Cu–Al alloys have been refined to the nano scale after deformed by SHPB, and with decreasing SFE, the average grain size decreases gradually from 72 to 40 nm, while the dislocation density increases from 0.55×10 14 to 4.4×10 14 m −2 and the twin density increases from 0.04% to 1.07%. The formation of deformation twins is an additional factor that contributes to the microhardness and strength of Cu and Cu–Al alloys except the solid solution strengthening effect. Cu-15 at%Al has the biggest strain hardening rate at larger strains due to its lowest SFE which results in the highest twin density. The results confirm that lower SFE improves both strength and strain hardening rate of materials
Conducting mechanisms of forming-free TiW/Cu{sub 2}O/Cu memristive devices

Energy Technology Data Exchange (ETDEWEB)

Yan, P.; Li, Y.; Hui, Y. J.; Zhong, S. J.; Zhou, Y. X.; Xu, L.; Liu, N.; Qian, H.; Sun, H. J., E-mail: shj@mail.hust.edu.cn; Miao, X. S. [Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074 (China); School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)

2015-08-24

P-type Cu{sub 2}O is a promising CMOS-compatible candidate to fabricate memristive devices for next-generation memory, logic and neuromorphic computing. In this letter, the microscopic switching and conducting mechanisms in TiW/Cu{sub 2}O/Cu memristive devices have been thoroughly investigated. The bipolar resistive switching behaviors without an electro-forming process are ascribed to the formation and rupture of the conducting filaments composed of copper vacancies. In the low resistive state, the transport of electrons in the filaments follows Mott's variable range hopping theory. When the devices switch back to high resistive state, the coexistence of Schottky emission at the Cu/Cu{sub 2}O interface and electron hopping between the residual filaments is found to dominate the conducting process. Our results will contribute to the further understanding and optimization of p-type memristive materials.
Cu-Doping Effects in CdI(2) Nanocrystals: The Role of Cu-Agglomerates.

Science.gov (United States)

Miah, M Idrish

2008-11-22

Cu-doping effects in CdI(2) nanocrystals are studied experimentally. We use the photostimulated second harmonic generation (PSSHG) as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to 0.6% and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1% reduces to that for the undoped CdI(2) crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects.
Cu-Doping Effects in CdI2Nanocrystals: The Role of Cu-Agglomerates

Directory of Open Access Journals (Sweden)

Miah M

2008-01-01

Full Text Available Abstract Cu-doping effects in CdI2nanocrystals are studied experimentally. We use the photostimulated second harmonic generation (PSSHG as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to 0.6% and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1% reduces to that for the undoped CdI2crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects.
Loss mechanisms in hydrazine-processed Cu2ZnSn(Se,S)4 solar cells

Science.gov (United States)

Gunawan, Oki; Todorov, Teodor K.; Mitzi, David B.

2010-12-01

We present a device characterization study for hydrazine-processed kesterite Cu2ZnSn(Se,S)4 (CZTSSe) solar cells with a focus on pinpointing the main loss mechanisms limiting device efficiency. Temperature-dependent study and time-resolved photoluminescence spectroscopy on these cells, in comparison to analogous studies on a reference Cu(In,Ga)(Se,S)2 (CIGS) cell, reveal strong recombination loss at the CZTSSe/CdS interface, very low minority-carrier lifetimes, and high series resistance that diverges at low temperature. These findings help identify the key areas for improvement of these CZTSSe cells in the quest for a high-performance indium- and tellurium-free solar cell.
P-type Cu2O/SnO bilayer thin film transistors processed at low temperatures

KAUST Repository

Al-Jawhari, Hala A.

2013-10-09

P-type Cu2O/SnO bilayer thin film transistors (TFTs) with tunable performance were fabricated using room temperature sputtered copper and tin oxides. Using Cu2O film as capping layer on top of a SnO film to control its stoichiometry, we have optimized the performance of the resulting bilayer transistor. A transistor with 10 nm/15 nm Cu2O to SnO thickness ratio (25 nm total thickness) showed the best performance using a maximum process temperature of 170 C. The bilayer transistor exhibited p-type behavior with field-effect mobility, on-to-off current ratio, and threshold voltage of 0.66 cm2 V-1 s-1, 1.5×10 2, and -5.2 V, respectively. The advantages of the bilayer structure relative to single layer transistor are discussed. © 2013 American Chemical Society.
Preparation of PtSnCu/C and PtSn/C electrocatalysts and activation by dealloying processes for ethanol electrooxidation

International Nuclear Information System (INIS)

Crisafulli, Rudy

2013-01-01

PtSnCu/C (with different Pt:Sn:Cu atomic ratios) and PtSn/C (50:50) electrocatalysts were prepared by borohydride (BR) and alcohol-reduction (AR) processes using H 2 PtCl 6 .6H 2 O, SnCl 2 .2H 2 O and CuCl 2 .2H 2 O as metal sources, NaBH 4 and ethylene glycol as reducing agents, 2-propanol and ethylene glycol/water as solvents and carbon black as support. In a further step, these electrocatalysts were activated by chemical (CD) and electrochemical (ED) dealloying processes through acid treatment and thin porous coating technique, respectively. These materials were characterized by energy dispersive X-ray, Xray diffraction, transmission electron microscopy, line scan energy dispersive Xray and cyclic voltammetry. Electrochemical studies for ethanol electro-oxidation were performed by cyclic voltammetry, chronoamperometry and in single Direct Ethanol Fuel Cell using Membrane Electrode Assembly (MEA). The anodic effluents were analysed by gas chromatography. The X-ray diffractograms of the as-synthesized electrocatalysts showed the typical face-centered cubic structure (FCC) of platinum and its alloys. After dealloying, the X-ray diffractograms showed that the Pt FCC structure was preserved. The crystallite sizes of the assynthesized electrocatalysts were in the range of PtSnCu/C (50:40:10) AR/ED > PtSnCu/C (50:10:40) BR/CD. PtSn/C (50:50) BR/CD, PtSnCu/C (50:10:40) BR/CD, PtSnCu/C (50:40:10) AR/CD electrocatalysts and Pt/C BASF, PtSn/C (75:25) BASF commercial electrocatalysts were tested in single Direct Ethanol Fuel Cell. The results showed the following performance for ethanol electro-oxidation: PtSn/C (50:50) BR/CD > PtSnCu/C (50:40:10) AR/CD > PtSnCu/C > PtSn/C (75:25) BASF > PtSnCu/C (50:10:40) BR/CD > Pt/C BASF. (author)
Formation of layered microstructure in the Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O superconductors

International Nuclear Information System (INIS)

Jin, S.; Kammlott, G.W.; Tiefel, T.H.; Chen, S.K.

1992-01-01

The layered grain microstructure is essential for overcoming the weak link problem and ensuring high transport critical currents in the cuprate superconductors. In this paper we discuss the processing and the mechanisms for layer information in Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O. In melt-processed Y-Ba-Cu-O, sympathetic nucleation on previously nucleated YBa 2 Cu 3 O 7-δ plates during solidification appears to be dominant mechanism for the formation of parallel plate-shaped grains. In the Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O ribbons, the interface reaction between the superconductor layer and the silvers substrate seems to be the main mechanism for the c-axis texturing of the layered grains. The drastically different critical current behavior in the c-axis textured Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O ribbons is discussed in terms of possible differences in the nature of the twist and tilt grain boundaries. (orig.)
A flexible angle sensor made from MWNT/CuO/Cu{sub 2}O nanocomposite films deposited by an electrophoretic co-deposition process

Energy Technology Data Exchange (ETDEWEB)

Toboonsung, Buppachat, E-mail: buppachattt@yahoo.co.th [Physics and General Science Program, Faculty of Science and Technology, Nakhon Ratchasima Rajabhat University, Nakhon Ratchasima 30000 (Thailand); Singjai, Pisith, E-mail: singjai@hotmail.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200 (Thailand)

2012-08-25

Highlights: Black-Right-Pointing-Pointer MWNT/CuO/Cu{sub 2}Onanocomposite films were coated on a PET sheet. Black-Right-Pointing-Pointer The film resistance and application as angle sensor were investigated. Black-Right-Pointing-Pointer Thesensor showed a linear relation between the film resistance and the bending angle. Black-Right-Pointing-Pointer A minimum loop area and a high stability in sensitivity over a thousand bending cycles were obtained. - Abstract: A flexible angle sensor was prepared using an electrophoretic co-deposition process to form nanocomposite networks of multi-wall carbon nanotube/cupric oxide/cuprous oxide (MWNT/CuO/Cu{sub 2}O) on a polyethylene terephthalate (PET) sheet. The deposition method used copper and stainless steel electrodes, and the effects of varying of electrode separation, MWNT concentration in deionized water, voltage and deposition time were studied. The film resistance of the as-deposited samples decreased with increasing the MWNT concentration up to 0.3 mg/ml. The angle sensor showed a linear relation between the film resistance and the bending angle, a relationship that was illustrated with loop area and sensitivity data. The best angle sensor was successfully made with an electrode separation of 8 mm, a concentration of 0.3 mg/ml, a voltage of 10 V and a deposition time of 3 h, parameters that resulted in a minimum loop area and the most stability in sensitivity over a thousand bending cycles.
Ceramic Composites of 3Y-TZP Doped with CuO: Processing, Microstructure and Tribology

NARCIS (Netherlands)

Ran, S.

2006-01-01

The work described in this thesis is about processing, microstructure and tribology of CuO doped 3Y-TZP (3 mol% yttria stabilised tetragonal zirconia polycrystals) composite ceramics. This group of materials has shown attractive properties such as superplastic behaviour at elevated temperature and a
Levels of Processing with Free and Cued Recall and Unilateral Temporal Lobe Epilepsy

Science.gov (United States)

Lespinet-Najib, Veronique; N'Kaoua, Bernard; Sauzeon, Helene; Bresson, Christel; Rougier, Alain; Claverie, Bernard

2004-01-01

This study investigates the role of the temporal lobes in levels-of-processing tasks (phonetic and semantic encoding) according to the nature of recall tasks (free and cued recall). These tasks were administered to 48 patients with unilateral temporal epilepsy (right ''RTLE''=24; left ''LTLE''=24) and a normal group (n=24). The results indicated…
Task Difficulty Differentially Affects Two Measures of Processing Load: The Pupil Response during Sentence Processing and Delayed Cued Recall of the Sentences

Science.gov (United States)

Zekveld, Adriana A.; Festen, Joost M.; Kramer, Kramera

2013-01-01

Purpose: In this study, the authors assessed the influence of masking level (29% or 71% sentence perception) and test modality on the processing load during language perception as reflected by the pupil response. In addition, the authors administered a delayed cued stimulus recall test to examine whether processing load affected the encoding of…
A study of the formation processes of the 2212 phase in the Bi-based superconductor systems. [BiSrCaCuO

Energy Technology Data Exchange (ETDEWEB)

Wai, Lo; Glowacki, B A [Interdisciplinary Research Centre in Superconductivity, Univ. of Cambridge (United Kingdom)

1992-04-15

A study towards the identification of the reactions contributing to and accompanying the formation of the 2212 phase from oxides and carbonates by solid state reaction processes was conducted. The formation processes were investigated by thermal analysis, powder X-ray diffractometry and AC magnetic susceptometry. The 2212 phase was found to form from reactions between the 2201 phases (the non-superconducting pseudo-tetragonal and the superconducting monoclinic phases), Bi{sub 6}Ca{sub 7}O{sub 16}, CuO and SrCO{sub 3}. The 2201 phases were produced by the reactions of Bi-Sr-Cu-O or Bi-Sr-O compounds with SrCO{sub 3} or CuO. The 2201 phases could also be formed through the direct reaction between Bi{sub 2}CuO{sub 4} and SrCO{sub 3}. (orig.).
Stress-strain effects in alumina-Cu reinforced Nb3Sn wires fabricated by the tube process

International Nuclear Information System (INIS)

Murase, Satoru; Nakayama, Shigeo; Masegi, Tamaki; Koyanagi, Kei; Nomura, Shunji; Shiga, Noriyuki; Kobayashi, Norio; Watanabe, Kazuo.

1997-01-01

In order to fabricate a large-bore, high-field magnet which achieves a low coil weight and volume, a high strength compound superconducting wire is required. For those demands we have developed the reinforced Nb 3 Sn wire using alumina dispersion strengthened copper (alumina-Cu) as a reinforcement material and the tube process of the Nb 3 Sn wire fabrication. The ductility study of the composites which consisted of the reinforcement, Nb tube, Cu, and Cu clad Sn brought a 1 km long alumina-Cu reinforced Nb 3 Sn wire successfully. Using fabricated wires measurements and evaluations of critical current density as parameters of magnetic field, tensile stress, tensile strain, and transverse compressive stress, and those of stress-strain curves at 4.2 K were performed. They showed superior performance such as high 0.3% proof stress (240 MPa at 0.3% strain) and high maximum tolerance stress (320 MPa) which were two times as large as those of conventional Cu matrix Nb 3 Sn wire. The strain sensitivity parameters were obtained for the reinforced Nb 3 Sn wire and the Cu matrix one using the scaling law. Residual stress of the component materials caused by cooling down to 4.2 K from heat-treatment temperature was calculated using equivalent Young's modulus, equivalent yield strength, thermal expansion coefficient and other mechanical parameters. Calculated stress-strain curves at 4.2 K for the reinforced Nb 3 Sn wire and the Cu matrix one based on calculation of residual stress, had good agreement with the experimental values. (author)

The mechanism of degradation of bisphenol A using the magnetically separable CuFe_2O_4/peroxymonosulfate heterogeneous oxidation process

International Nuclear Information System (INIS)

Xu, Yin; Ai, Jia; Zhang, Hui

2016-01-01

Highlights: • Copper ferrite (CuFe_2O_4) was fabricated and utilized in heterogeneous PMS process. • The influence of reaction parameters for the mineralization of BPA were evaluated. • Possible reaction mechanism and the stability of CuFe_2O_4 were investigated. • Surface bound radicals (mainly ·OH) may be responsible for the BPA degradation. - Abstract: The removal of bisphenol A (BPA) in aqueous solution by an oxidation process involving peroxymonosulfate (PMS) activated by CuFe_2O_4 magnetic nanoparticles (MNPs) is reported herein. The effects of PMS concentration, CuFe_2O_4 dosage, initial pH, initial BPA concentration, catalyst addition mode, and anions (Cl"−, F"−, ClO_4"− and H_2PO_4"−) on BPA degradation were investigated. Results indicate that nearly complete removal of BPA (50 mg/L) within 60 min and 84.0% TOC removal in 120 min could be achieved at neutral pH by using 0.6 g/L CuFe_2O_4 MNPs and 0.3 g/L PMS. The generation of reactive radicals (mainly hydroxyl radicals) was confirmed using electron paramagnetic resonance (EPR). Possible mechanisms on the radical generation from CuFe_2O_4/PMS system are proposed based on the results of radical identification tests and XPS analysis. The lack of inhibition of the reaction by free radical scavengers such as methanol and tert-butyl alcohol suggests that these species may not be generated in the bulk solution, and methylene blue probe experiments confirm that this process does not involve free radical generation. Surface-bound, rather than free radicals generated by a surface catalyzed-redox cycle involving both Fe(III) and Cu(II), are postulated to be responsible for the mineralization of bisphenol A.
Counter-current acid leaching process for the removal of Cu, Pb, Sb and Zn from shooting range soil.

Science.gov (United States)

Lafond, Stéphanie; Blais, Jean-François; Mercier, Guy; Martel, Richard

2013-01-01

This research explores the performance of a counter-current leaching process (CCLP) for Cu, Pb, Sb and Zn extraction in a polluted shooting range soil. The initial metal concentrations in the soil were 1790 mg Cu/kg, 48,300 mg Pb/kg, 840 mg Sb/kg and 368 mg Zn/kg. The leaching process consisted of five one-hour acid leaching steps, which used 1 M H2SO4 + 4 M NaCl (20 degrees C, soil suspension = 100 g/L) followed by two water rinsing steps. Ten counter-current remediation cycles were completed and the average metal removal yields were 98.3 +/- 0.3% of Cu, 99.5 +/- 0.1% of Pb, 75.5 +/- 5.1% of Sb and 29.1 +/- 27.2% of Zn. The quality of metal leaching did not deteriorate throughout the 10 remediation cycles completed for this study. The CCLP reduced acid and salt use by approximately 68% and reduced water consumption by approximately 60%, exceeding reductions achieved by a standard acid leaching process.
Cu-Cr Literature Review

Energy Technology Data Exchange (ETDEWEB)

Need, Ryan F. [Los Alamos National Laboratory

2012-08-09

Cu-Cr alloys are part of a class of face-centered cubic (FCC)-body-centered cubic (BCC) composites that includes similar alloys, such as Cu-Nb and Cu-Ta. When heavily deformed, these FCC-BCC materials create 'in situ' composites with a characteristic structure-nanoscale BCC filaments in a ductile FCC matrix. The strength of these composites is vastly greater than predicted by the rule of mixtures, and has been shown to be inversely proportional to the filament spacing. Lower raw materials costs suggest that Cu-Cr alloys may offer more economical solution to high-strength, high-conductivity wire than either their Nb or Ta counterparts. However, Cr is also more brittle and soluble in Cu than Nb or Ta. These qualities necessitate thermal treatments to remove solute atoms from the Cu matrix, improve conductivity, and maintain the ductility of the Cr filaments. Through the use of different thermomechanical processing routes or the addition of select dopants, alloys with strength in excess of 1 GPa at 70% IACS have been achieved. To date, previous research on Cu-Cr alloys has focused on a relatively small number of alloy compositions and processing methods while the effects of dopants and ageing treatments have only been studied independently. Consequently, there remains considerable opportunity for the development and optimization of these alloys as a leading high-strength, high-conductivity material.
Effect of gate dielectrics on the performance of p-type Cu2O TFTs processed at room temperature

KAUST Repository

Al-Jawhari, Hala A.

2013-12-01

Single-phase Cu2O films with p-type semiconducting properties were successfully deposited by reactive DC magnetron sputtering at room temperature followed by post annealing process at 200°C. Subsequently, such films were used to fabricate bottom gate p-channel Cu2O thin film transistors (TFTs). The effect of using high-κ SrTiO3 (STO) as a gate dielectric on the Cu2O TFT performance was investigated. The results were then compared to our baseline process which uses a 220 nm aluminum titanium oxide (ATO) dielectric deposited on a glass substrate coated with a 200 nm indium tin oxide (ITO) gate electrode. We found that with a 150 nm thick STO, the Cu2O TFTs exhibited a p-type behavior with a field-effect mobility of 0.54 cm2.V-1.s-1, an on/off ratio of around 44, threshold voltage equaling -0.62 V and a sub threshold swing of 1.64 V/dec. These values were obtained at a low operating voltage of -2V. The advantages of using STO as a gate dielectric relative to ATO are discussed. © (2014) Trans Tech Publications, Switzerland.
Optical properties of La2CuO4 and La2−xCaxCuO4 crystallites in UV–vis–NIR region synthesized by sol–gel process

International Nuclear Information System (INIS)

Li Yifeng; Huang Jianfeng; Cao Liyun; Wu Jianpeng; Fei Jie

2012-01-01

La 2 CuO 4 and La 2−x Ca x CuO 4 crystallites were prepared via a simple sol–gel process. The as-prepared La 2 CuO 4 and La 2 −x Ca x CuO 4 crystallites were characterized by X-ray diffraction, transmission electron microscope and UV–vis–NIR spectra. Results show that the grain size of La 2 CuO 4 crystallites increases with the increase of heat treatment temperature from 600 °C to 800 °C. Optical properties show that La 2 CuO 4 crystallites have broad absorption both in the UV–vis region and in the NIR region. The band gap of the as-prepared crystallites decreases from 1.367 eV to 1.284 eV with the increase of calcination temperature from 600 °C to 800 °C. In the series of La 2−x Ca x CuO 4 compounds (x = 0.05, 0.08, 0.10, 0.12, 0.15 and 0.20), all of the samples exhibit an orthogonal crystal structure and the solubility limit of Ca 2+ in La 2 CuO 4 is within the range of x = 0.12–0.15. In the whole UV–vis–NIR region, La 2−x Ca x CuO 4 crystallites exhibit a broad absorption and the corresponding band gap first increases and then decreases with increasing of Ca 2+ content. - Highlights: ► The optical band gap can be tuned by adjusting the grain size and Ca 2+ content. ► La 2 CuO 4 crystallites exhibit a broad absorption band both in the UV–vis region and in the NIR region. ► The band gap increases from 1.284 eV to 1.319 eV with the decrease of heat treatment temperature. ► In the whole UV–vis–NIR region, the La 2−x Ca x CuO 4 crystallites displayed a broad absorption. ► The band gap of La 2−x Ca x CuO 4 increases linearly with doping level when 0 ≤ x ≤ 0.12.
Surface chemistry of 2-butanol and furfural on Cu, Au and Cu/Au single crystals

OpenAIRE

Megginson, Rory

2016-01-01

In this study, the adsorption of 2-butanol and furfural was investigated on Au (111), Cu (111) and Cu/Au (111) surfaces. It was hoped that by studying how these species adsorbed on these surfaces , insight would be provided into the roles of Cu and Au in the “hydrogen free” hydrogenation of furfural to furfuryl alcohol. This is a valuable process as currently furfuryl alcohol is derived from crude oil but it is possible to derive furfural from corn husk making it a greener process...
Microstructures and mechanical properties evolution of an Al–Fe–Cu alloy processed by repetitive continuous extrusion forming

Energy Technology Data Exchange (ETDEWEB)

Kong, Xiangxin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Zhang, Hui, E-mail: zhanghui63hunu@163.com [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082 (China); Ji, Xiankun [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

2014-08-26

Repetitive continuous extrusion forming process (R-Conform process), as a continuous severe plastic deformation method, was performed on a horizontal continuous casting Al–0.74Fe–0.23Cu alloy. The microstructural evolution and mechanical properties were studied by optical microscope, X-ray diffraction, scanning electron microscope, transmission electron microscope, and tensile testing. The results show that tensile ductility of the Al–0.74Fe–0.23Cu alloy is greatly improved but tensile strength is gradually decreased after repetitive Conform processing. The necking is more intense and the size of dimples becomes bigger with increasing Conform passes. The first pass Conform process induces obviously grains refining, dissolution of AlFe, AlFeSi and AlSi primary phases, strain-induced precipitation and transformation of crystal orientation distributions, but further Conform deformation only changes the redistribution of precipitates. The changes of mechanical properties may be attributed to a complex progress of recovery, recrystallization and redistribution of precipitates during repetitive Conform process.
High-density Bi-Pb-Sr-Ca-Cu-O superconductor prepared by rapid thermal melt processing

Science.gov (United States)

Moon, B. M.; Lalevic, B.; Kear, B. H.; McCandlish, L. E.; Safari, A.; Meskoob, M.

1989-10-01

A high quality, dense Bi-Pb-Sr-Ca-Cu-O superconductor has been successfully synthesized by rapid thermal melt processing. Conventionally sintered pellets were melted at 1200 °C, cooled rapidly, and then annealed. As-melted samples exhibited semiconductor behavior, which upon annealing became superconducting at 115 K [Tc(zero)=105 K]. A detailed study of various processing techniques has been carried out.
Process parameters, orientation, and functional properties of melt-processed bulk Y-Ba-Cu-O superconductors

International Nuclear Information System (INIS)

Zakharchenko, I.V.; Terryll, K.M.; Rao, K.V.; Balachandran, U.

1995-03-01

This study compared the microstructure, texturing, and functional properties (critical currents) of YBa 2 Cu 3 O 7-x -based bulk pellets that were prepared by the quench-melt-growth-process (QMGP), melt-textured growth (MTG), and conventional solid-state reaction (SSR) approaches. Using two X-ray diffraction (XRD) methods, θ-2θ, and rocking curves, the authors found that the individual grains of two melt-processed pellets exhibited remarkable preferred orientational alignment (best rocking curve width = 3.2 degree). However, the direction of the preferred orientation among the grains was random. Among the three types of bulk materials studied, the QMGP sample was found to have the best J c values, ∼ 4,500 A/cm 2 at 77 K in a field of 2 kG, as determined from SQUID magnetic data
Colloidal Precursors from 'Ball-Milling in Liquid Medium' Process for CuInSe{sub 2} Thin Film

Energy Technology Data Exchange (ETDEWEB)

Chung, Jae Hoon; Kim, Seung Joo [Ajou University, Suwon (Korea, Republic of)

2010-09-15

CIS thin film can be fabricated by using the precursor obtained through ball-milling the elemental reagents in liquid media. The amorphous colloidal precursor with good dispersity was prepared in the medium that contains strong base and polar solvent (2 M ethylenediamine in DMF solution as used in this study). The 'ball-milling in liquid medium' method requires only elemental sources as starting materials and a proper solution so that it can be employed without additional processes for separation and purification. As a simple and less-toxic preparative route, this method would be practically available to prepare CIS-related solar cells. CuInSe{sub 2} (CIS) and related chalcopyrite compounds are very promising materials for thin film solar cells due to their favorable band gap, high optical absorption coefficient and long-term stability. CIS-based solar cells have shown the highest conversion efficiency reaching a value of 20%. However, the vacuum-based processes that are used to fabricate CIS thin-films have some drawbacks such as the complexity in process, high production cost and difficulty in scaling up. Recently, several research groups have proposed different non-vacuum deposition processes for CIS solar cell. For example, H. W. Hillhouse et al. prepared the CIS absorber layer by using 'nanocrystal ink method' in which a colloidal nanocrystal ink was obtained from reaction of CuCl, InCl{sub 3} and Se in oleylamine. D. B. Mitzi et al. used a solution-based precursor that was prepared by dissolution of Cu{sub 2}Se, In{sub 2}Se{sub 3}, Ga{sub 2}Se{sub 3} and Se in hydrazine to fabricate the Ga-containing absorber layer, Cu(In,Ga)Se{sub 2}.
Microstructure and transport current characterization of YBa2Cu3O7-x thick films prepared by modified solid-liquid melt growth and powder melt process routes

International Nuclear Information System (INIS)

Langhorn, J.; McGinn, P.J.

1999-01-01

From the characterization of superconducting YBa 2 Cu 3 O 7-x (YBCO) thick films processed by melt texturing on yttria-stabilized zirconia substrates from YBCO precursors it is clear that the properties are highly dependent on the precursor powder. Increased YBCO grain sizes have been induced in thick films processed from by modified solid-liquid melt growth (SLMG) and powder melt (PMP) processes with respect to those processed from pre-reacted YBCO materials. The SLMG and PMP routes utilize precursors consisting of BaCuO 2 -CuO flux material mixed with Y 2 O 3 and Y 2 BaCuO 5 respectively. Cross-sectional analysis of films textured by these routes shows a decreased Y 2 BaCuO 5 size and an increased homogeneity within the matrix with respect to films processed from YBCO powder. Such microstructural improvements lead to an improvement of both the flux pinning and current-carrying characteristics of the processed YBCO films. (author)
Cu-Fe welding techniques by electromagnetic and electron beam welding processes

International Nuclear Information System (INIS)

Kumar, Satendra; Saroj, P.C.; Kulkarni, M.R.; Sharma, A.; Rajawat, R.K.; Saha, T.K.

2015-01-01

Electromagnetic welding being a solid state welding process has been found suitable for welding Copper and Iron which are conventionally very tricky. Owing to good electrical conductivity of both copper and iron, they are best suited combination for EM welding. For the experimental conditions presented above, 1.0 mm wall thickness of Cu tube was lap welded to Fe disc. A heavy duty four disc stainless steel coil was used for electromagnetic welding of samples. MSLD of the welded samples indicated leak proof joints. Metallographic examination of the welds also revealed defect free interfaces. Electron beam welding is also a non-conventional welding process used for joining dissimilar materials. Autogenous welding of the above specimen was carried out by EBW method for the sake of comparison. A characterization analysis of the above mentioned joining processes will be discussed in the paper. (author)
Cu and Cu2O films with semi-spherical particles grown by electrochemical deposition

International Nuclear Information System (INIS)

Zheng, Jin You; Jadhav, Abhijit P.; Song, Guang; Kim, Chang Woo; Kang, Young Soo

2012-01-01

Cu and Cu 2 O films can be prepared on indium-doped tin oxide glass substrates by simple electrodeposition in a solution containing 0.1 M Cu(NO 3 ) 2 and 3 M lactic acid at different pH values. At low pH (pH = 1.2), the uniform Cu films were obtained; when pH ≥ 7, the pure Cu 2 O films can be deposited. Especially, at pH = 11, the deposited Cu 2 O films exhibited cubic surface morphology exposing mainly {100} plane; in contrast, the films consisting of semi-spherical particles were obtained when the solution was being stirred for 2 weeks prior to use. The possible growth process and mechanism were comparatively discussed. - Highlights: ► Cu and Cu 2 O films were prepared by facile electrodeposition. ► Electrodeposition was preformed in electrolyte at different pH values. ► Dendritic Cu films were obtained at 1.2 pH with relatively high deposition potential. ► Semi-spherical Cu 2 O films were obtained with solution at 11 pH and stirred for 2 weeks. ► The possible growth mechanism of semi-spherical Cu 2 O films was discussed.
Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

Directory of Open Access Journals (Sweden)

Liu Mei Lee

2013-01-01

Full Text Available This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.
Study on the process of sintering matrix metallic Fe-Cu-25%Nb and Fe-Cu-25%Co during hot pressing

International Nuclear Information System (INIS)

Batista, A.C.; Oliveira, H.C.P.; Souza, M.H.; Assis, P.S.

2016-01-01

The sintering process promotes densification and the evolution of the microstructure of the material, with consequent significant increase in hardness and mechanical strength. However, few studies show the influence of pressure and temperature during sintering by hot pressing. In this sense, this work aims to evaluate the microstructural changes and properties with the variation of pressure and temperature and the type suffered by sintering metal powders during sintering by hot pressing. For this, two samples were studied by changing the sintering parameters: 25% Fe-50% Cu-25% Nb and 25% Fe-50% Cu-25% Co. Samples were analyzed by SEM / EDS in order to check the morphology and the presence of pores, as well as the interaction between the metallic constituents of each sample by the EDS analysis in line. They also determined the relative density, porosity and Vickers hardness (HV5). At the end of the study it was concluded that niobium alloy composite element by sintering activated suffered together with the liquid phase sintering. For cobalt alloys were observed by liquid phase sintering. The increase in the severity of the sintering conditions (temperature and pressure) led to an improvement in physical and mechanical properties of the alloys, which indicates that these parameters are directly related to the mechanisms of diffusion in the sintering process, improving the properties and diffusivity between elements. (author)
Colloidal Precursors from 'Ball-Milling in Liquid Medium' Process for CuInSe2 Thin Film

International Nuclear Information System (INIS)

Chung, Jae Hoon; Kim, Seung Joo

2010-01-01

CIS thin film can be fabricated by using the precursor obtained through ball-milling the elemental reagents in liquid media. The amorphous colloidal precursor with good dispersity was prepared in the medium that contains strong base and polar solvent (2 M ethylenediamine in DMF solution as used in this study). The 'ball-milling in liquid medium' method requires only elemental sources as starting materials and a proper solution so that it can be employed without additional processes for separation and purification. As a simple and less-toxic preparative route, this method would be practically available to prepare CIS-related solar cells. CuInSe 2 (CIS) and related chalcopyrite compounds are very promising materials for thin film solar cells due to their favorable band gap, high optical absorption coefficient and long-term stability. CIS-based solar cells have shown the highest conversion efficiency reaching a value of 20%. However, the vacuum-based processes that are used to fabricate CIS thin-films have some drawbacks such as the complexity in process, high production cost and difficulty in scaling up. Recently, several research groups have proposed different non-vacuum deposition processes for CIS solar cell. For example, H. W. Hillhouse et al. prepared the CIS absorber layer by using 'nanocrystal ink method' in which a colloidal nanocrystal ink was obtained from reaction of CuCl, InCl 3 and Se in oleylamine. D. B. Mitzi et al. used a solution-based precursor that was prepared by dissolution of Cu 2 Se, In 2 Se 3 , Ga 2 Se 3 and Se in hydrazine to fabricate the Ga-containing absorber layer, Cu(In,Ga)Se 2
Synthesis of core-shell heterostructured Cu/Cu2O nanowires monitored by in situ XRD as efficient visible-light photocatalysts

KAUST Repository

Chen, Wei

2013-01-01

Core-shell heterostructured Cu/Cu2O nanowires with a high aspect ratio were synthesized from Cu foam using a novel oxidation/reduction process. In situ XRD was used as an efficient tool to acquire phase transformation details during the temperature-programmed oxidation of Cu foam and the subsequent reduction process. Based on knowledge of the crucial phase transformation, optimal synthesis conditions for producing high-quality CuO and core-shell Cu/Cu2O nanowires were determined. In favor of efficient charge separation induced by the special core-shell heterostructure and the advanced three-dimensional spatial configuration, Cu/Cu2O nanowires exhibited superior visible-light activity in the degradation of methylene blue. The present study illustrates a novel strategy for fabricating efficiently core-shell heterostructured nanowires and provides the potential for developing their applications in electronic devices, for environmental remediation and in solar energy utilization fields. This journal is © The Royal Society of Chemistry.
Design and Synthesis of novel CuxGeOy/Cu/C nanowires by in situ chemical reduction process with highly reversible capacity for Lithium Batteries

International Nuclear Information System (INIS)

Wang, Linlin; Zhang, Xiaozhu; Peng, Xia; Tang, Kaibin

2015-01-01

The synthesis and use of ternary metal oxides/metal particles/carbon hybrids, especially 1D naowires composed of MGeO 3 /M/C hybrids for energy storage, remains very few reports. In this work, 1D Cu x GeO y /Cu/C NWs (x < 1, y < 3) were successfully prepared by a simple method involving chemical reduction process and simultaneous carbon coating. It was found that through the polydopamine(PDA)-assisted chemical reduction process performed on the CuGeO 3 NWs, the phase partially transformed to a mixture of crystalline Cu (∼70 nm) and amorphous Cu x GeO y NWs with carbon coating, but the nanowire-shaped morphology was maintained. Electrochemical measurements showed that the Cu x GeO y /Cu/C NWs exhibited a stable reversible capacity of ∼900 mA h g −1 after 100 cycles. Even at 800 mA g −1 , it also exhibited excellent high rate capacity of 350 mA h g −1 . The newly generated Cu x GeO y @Cu@CNWs exhibit enhanced cycle stability with high lithium-storage capability compared to that of the as-preparedCuGeO 3 NWs. (*) The in situ-synthesized Cu nanoparticles, amorphous state and carbon coating might play an important role in activating and enhancing the reversibility of the conversion reaction of Cu x GeO y . In addition, this effective synthetic method might provide the methodology for the development of other ternary metal oxides/metal particles/carbon hybrids materials for energy storage.
Melt processing of the Bi2Sr2CaCu2Oy superconductor in oxygen and argon atmospheres

International Nuclear Information System (INIS)

Holesinger, T.G.; Miller, D.J.; Chumbley, L.S.

1992-08-01

Solidification and subsequent annealing of Bi 2 Sr 2 CaCu 2 O y (2212) in oxygen and argon atmospheres were investigated in order to identify alternative processing routes for controlling microstructures and superconducting properties. In addition to 2212, several other phases formed on cooling in O 2 and did not disappear upon subsequent annealing. Crystallization in Ar resulted in a divorced eutetic structure of Bi 2 Sr 3-x Ca x O y and Cu 2 O/CuO. The superconductor was formed on subsequent anneals. Samples melted in Ar and then annealed generally possessed a more uniform microstructure compared with samples that were melted in oxygen and annealed. Compositional measurements of the 2212 phase suggest that CaO segregation in the melt may be minimized with an overall composition such as Bi 2.15 Sr 2 Ca 0.85 Cu 2 O y
An Alternative Cu-Based Bond Layer for Electric Arc Coating Process

Science.gov (United States)

Fadragas, Carlos R.; Morales, E. V.; Muñoz, J. A.; Bott, I. S.; Lariot Sánchez, C. A.

2011-12-01

A Cu-Al alloy has been used as bond coat between a carbon steel substrate and a final coating deposit obtained by applying the twin wire electric arc spraying coating technique. The presence of a copper-based material in the composite system can change the overall temperature profile during deposition because copper exhibits a thermal conductivity several times higher than that of the normally recommended bond coat materials (such as nickel-aluminum alloys or nickel-chromium alloys). The microstructures of 420 and 304 stainless steels deposited by the electric arc spray process have been investigated, focusing attention on the deposit homogeneity, porosity, lamellar structure, and microhardness. The nature of the local temperature gradient during deposition can strongly influence the formation of the final coating deposit. This study presents a preliminary study, undertaken to investigate the changes in the temperature profile which occur when a Cu-Al alloy is used as bond coat, and the possible consequences of these changes on the microstructure and adhesion of the final coating deposit. The influence of the thickness of the bond layer on the top coating temperature has also been also evaluated.

A low-cost batch process for high-performance melt-textured GdBaCuO pellets

Czech Academy of Sciences Publication Activity Database

Muralidhar, M.; Tomita, M.; Suzuki, K.; Jirsa, Miloš; Fukumoto, .Y.; Ishihara, A.

2010-01-01

Roč. 23, č. 4 (2010), 045033/1-045033/7 ISSN 0953-2048 Institutional research plan: CEZ:AV0Z10100520 Keywords : superconducting magnet * GdBaCuO * batch process * high-Tc bulk Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.402, year: 2010
Controllable synthesis and enhanced photocatalytic properties of Cu2O/Cu31S16 composites

International Nuclear Information System (INIS)

Liu, Xueqin; Li, Zhen; Zhang, Qiang; Li, Fei

2012-01-01

Highlights: ► Facile sonochemical route. ► The content of Cu 31 S 16 in the Cu 2 O/Cu 31 S 16 can be easily controlled. ► Structure and optical properties of Cu 2 O/Cu 31 S 16 were discussed. ► Enhanced photocatalytic property of Cu 2 O/Cu 31 S 16 . ► Cu 2 O/Cu 31 S 16 core/shell structures were more stable than single Cu 2 O particles. -- Abstract: The controlled synthesis of Cu 2 O/Cu 31 S 16 microcomposites with hierarchical structures had been prepared via a convenient sonochemical route. Ultrasonic irradiation of a mixture of Cu 2 O and (NH 2 ) 2 CS in an aqueous medium yielded Cu 2 O/Cu 31 S 16 composites. The content of Cu 31 S 16 in the Cu 2 O/Cu 31 S 16 can be easily controlled by adjusting the synthesis time. The Cu 31 S 16 layer not only protected and stabilized Cu 2 O particles, but also prohibited the recombination of photogenerated electrons–holes pair between Cu 31 S 16 and Cu 2 O. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) spectra, ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence (PL) spectroscopy were used to characterize the products. Photocatalytic performance of the Cu 2 O/Cu 31 S 16 hierarchical structures was evaluated by measuring the decomposition rate of methyl orange solution under natural light. To the best of our knowledge, this is the first report on the preparation and photocatalytic activity of Cu 2 O/Cu 31 S 16 microcomposite. Additionally, the Cu 2 O/Cu 31 S 16 core/shell structures were more stable than single Cu 2 O particles during photocatalytic process since the photocatalytic activity of the second reused architecture sample was much higher than that of pure Cu 2 O. The Cu 2 O/Cu 31 S 16 microcomposites may be a good promising candidate for wastewater treatment.
Flux motion and anisotropy in melt-processed YBa2Cu3O7-δ

International Nuclear Information System (INIS)

Koblischka, M.R.; Schuster, Th.; Kuhn, H.; Gluecker, M.; Dalen, A.J.J. van; Griessen, R.; Kronmueller, H.

1993-01-01

The melt-processing of YBa 2 Cu 3 O 7-δ - and Bi 2 Sr 2 CaCu 2 O 8+δ -samples offers a promising way to achieve high critical current densities also in bulk materials. This is of main interest for strong current applications of high-T c superconductors. Interesting basic features can also be studied using melt-processed samples, from which good quality crystals can be cut out. For example, such samples make it possible to do measurements in various angular positions without drastically changing the demagnetizing factors along the main crystallographic axes. Usually, most measurements studying the influence of intrinsic pinning have been carried out on thin films (1). To observe flux distributions in superconductors, we use the High Resolution Faraday (HRF) technique. This enables one to local observations of flux distributions, combining a high spatial resolution (∼0.8 μm) with the unique possibility to observe dynamic processes in the flux distribution such as flux motion due to flux creep (2,3). Additionally, torque measurements up to 7 T in the temperature range 10 - 77 K have been carried out on the identical sample for a comparison of the local HRF data with integral critcal current torque data. (orig.)
Effect of selenization time on the structural and morphological properties of Cu(In,Ga)Se2 thin films absorber layers using two step growth process

Science.gov (United States)

Korir, Peter C.; Dejene, Francis B.

2018-04-01

In this work two step growth process was used to prepare Cu(In, Ga)Se2 thin film for solar cell applications. The first step involves deposition of Cu-In-Ga precursor films followed by the selenization process under vacuum using elemental selenium vapor to form Cu(In,Ga)Se2 film. The growth process was done at a fixed temperature of 515 °C for 45, 60 and 90 min to control film thickness and gallium incorporation into the absorber layer film. The X-ray diffraction (XRD) pattern confirms single-phase Cu(In,Ga)Se2 film for all the three samples and no secondary phases were observed. A shift in the diffraction peaks to higher 2θ (2 theta) values is observed for the thin films compared to that of pure CuInSe2. The surface morphology of the resulting film grown for 60 min was characterized by the presence of uniform large grain size particles, which are typical for device quality material. Photoluminescence spectra show the shifting of emission peaks to higher energies for longer duration of selenization attributed to the incorporation of more gallium into the CuInSe2 crystal structure. Electron probe microanalysis (EPMA) revealed a uniform distribution of the elements through the surface of the film. The elemental ratio of Cu/(In + Ga) and Se/Cu + In + Ga strongly depends on the selenization time. The Cu/In + Ga ratio for the 60 min film is 0.88 which is in the range of the values (0.75-0.98) for best solar cell device performances.
Synthesis and photocatalytic activity of carbon spheres loaded Cu2O/Cu composites

International Nuclear Information System (INIS)

Li, Yinhui; Zhao, Mengyao; Zhang, Na; Li, Ruijuan; Chen, Jianxin

2015-01-01

Highlights: • Carbon spheres loaded Cu 2 O/Cu composites are obtained by hydrothermal process. • Cu 2 O/Cu nanocrystals grow on the surface of carbon spheres. • The composites with core–shell structure show highly photo-catalytic activity. • The composites can degrade methyl orange under simulated solar light irradiation. • The composites can be used to treat dye wastewater or organic pollutants. - Abstract: In this work, using amylose as carbon source and cupric acetate as copper source, carbon spheres loaded Cu 2 O/Cu composites were obtained by hydrothermal synthesis. The effects of the molar ratios between glucose and Cu(II), and hydrothermal time on the morphology and sizes of the composites were investigated. The result of photocatalytic experiments demonstrated that the composites could degrade methyl orange in aqueous solution under simulated solar light irradiation. The highest degradation rate was achieved to 93.83% when the composites were prepared by hydrothermal synthesis at 180 °C for 16 h and the molar ratio between glucose and Cu(II) was 10/1. The composites, as new and promising materials, can be used to treat dye wastewater or other organic pollutants
Improvisation of mechanical and electrical properties of Cu by reinforcing MWCNT using modified electro-co-deposition process

Science.gov (United States)

Belgamwar, Sachin U.; Sharma, N. N.

2018-04-01

Multi-walled Carbon nanotubes–copper (MWCNT/Cu) composite powders with variable MWCNT content were synthesized by modified electro-co-deposition method. The electro-co-deposited MWCNT/Cu powders were consolidated by conventional compaction and sintering process. The consolidated products were then hot rolled and cold drawn to fine wires. The MWCNT/Cu composite wire samples were characterized for electrical and mechanical properties. We have been able to achieve an increase of around 8% in electrical conductivity of the form wires repeatedly. It has been observed that there was gradual improvement in the properties with reinforcement of MWCNT in the copper matrix. The betterment of electrical property has been achieved with simultaneous improvement in mechanical properties of the wire. The yield strength of MWCNT/Cu composite wire was found to be four times and the tensile strength two times greater than that of pure copper. The improved properties are attributed to the proper distribution of MWCNTs in the copper matrix and excellent interfacial bonding between MWCNT and composite copper fabricated by the modified method.
Effect of processing variables on microstructure and properties of two Al-Li-Cu-Mg-Zr alloys

International Nuclear Information System (INIS)

Palmer, I.G.; Lewis, R.E.; Crooks, D.D.

1984-01-01

Two Al-Li-Cu-Mg-Zr alloys have been prepared in the form of both powder metallurgy (PM) and ingot metallurgy (IM) alloys. The compositions were selected to meet certain program goals based on the results of an alloy development phase, the details of which have been previously published. The target compositions were Al-3Li-1.5Cu-1Mg-0.2Zr and Al-3Cu-2Li-1Mg-0.2Zr. The PM alloys were prepared from chill cast remelt stock by centrifugal atomization in helium, followed by screening, degassing, and extrusion. The IM alloys were prepared by direct chill (DC) casting, homogenization and extrusion. Full details of the production of the alloys are given. The effects of various processing conditions on microstructure and properties were evaluated, including different heat treatments and stretching conditions. These effects are described in detail with particular emphasis on a comparison of the PM and IM alloys. 10 references
Facile synthesis of dendritic Cu by electroless reaction of Cu-Al alloys in multiphase solution

Science.gov (United States)

Wang, Ying; Liang, Shuhua; Yang, Qing; Wang, Xianhui

2016-11-01

Two-dimensional nano- or micro-scale fractal dendritic coppers (FDCs) were synthesized by electroless immersing of Cu-Al alloys in hydrochloric acid solution containing copper chloride without any assistance of template or surfactant. The FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl2 + HCl solution. Compared to Cu40Al60 and Cu45Al55 alloys, the FDC shows hierarchical distribution and homogeneous structures using Cu17Al83 alloy as the starting alloy. The growth direction of the FDC is , and all angles between the trunks and branches are 60°. Nanoscale Cu2O was found at the edge of FDC. Interestingly, nanoporous copper (NPC) can also be obtained through Cu17Al83 alloy. Studies showed that the formation of FDC depended on two key factors: the potential difference between CuAl2 intermetallic and α-Al phase of dual-phase Cu-Al alloys; a replacement reaction that usually occurs in multiphase solution. The electrochemical experiment further proved that the multi-branch dendritic structure is very beneficial to the proton transfer in the process of catalyzing methanol.
R&D of CuCrZr tubes for W/Cu monoblock components

Energy Technology Data Exchange (ETDEWEB)

Zhao, Sixiang, E-mail: sxzhao@impcas.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), P.O. Box 1126, Hefei 230031 (China); Ma, Linsheng [State Nuclear Bao Ti Zirconium Industry Company, 206 Hi-Tech Avenue, Baoji 721013 (China); Peng, Lingjian [Advanced Technology & Materials Co., Ltd. - AT& M, Beijing 100081 (China); Gao, Bo [State Nuclear Bao Ti Zirconium Industry Company, 206 Hi-Tech Avenue, Baoji 721013 (China); Li, Chun [Laboratory of Advanced materials, School of Materials Science & Engineering, Tsinghua University, Beijing 100084 (China); Li, Qiang; Wang, Wanjing; Wei, Ran; Xu, Yuping [Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), P.O. Box 1126, Hefei 230031 (China); Pan, Ningjie; Qin, Sigui; Shi, Yingli; Liu, Guohui; Wang, Tiejun [Advanced Technology & Materials Co., Ltd. - AT& M, Beijing 100081 (China); Luo, Guang-Nan, E-mail: gnluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), P.O. Box 1126, Hefei 230031 (China); Hefei Center for Physical Science and Technology, Hefei 230031 (China); Hefei Science Center of CAS, Hefei 230031 (China)

2016-11-15

Highlights: • CuCrZr tubes with excellent HIP performance and good resistance to grain growth have been developed. • A circumferential ductility testing manner for small-diameter tubes has been utilized in this study. • The evolution of microstructures has been revealed throughout the new tube forming processes. - Abstract: In order to avoid the occurrence of two types of longitudinal defects (strain localization and folding flaws), which were observed in the CuCrZr tubes of EAST W/Cu upper divertor components, in the future manufacturing of monoblock components using hot isostatic pressing (HIP), a new CuCrZr tube forming protocol is proposed. The evolution of Cu grains and Cr-rich particles is monitored by scanning electron microscopy throughout the new tube forming processes. The final microstructures of the newly developed tubes are totally different from those of the EAST project previously chosen tubes and the elongation of Cr-rich precipitates has been substantially suppressed by using the new tube forming protocol. The newly developed tubes show better HIP performance than the EAST previously chosen ones. Since circumferential mechanical properties, especially ductility, are of great importance, a circumferential ductility testing manner for small-diameter tubes, which might be a supplement to longitudinal tensile testing, has been utilized and the preliminary testing results are given. The recrystallization behavior of the newly developed tubes is also investigated.
The Pd distribution and Cu flow pattern of the Pd-plated Cu wire bond and their effect on the nanoindentation

International Nuclear Information System (INIS)

Lin, Yu-Wei; Wang, Ren-You; Ke, Wun-Bin; Wang, I-Sheng; Chiu, Ying-Ta; Lu, Kuo-Chang; Lin, Kwang-Lung; Lai, Yi-Shao

2012-01-01

Highlights: ► Pd distribution in Pd-plated Cu wires reveals the whirlpool flow pattern of Cu. ► The mechanisms of the Cu flow behavior and Pd distribution are proposed. ► At Pd-rich phases, small voids formed and followed the direction of Cu flow. ► Nanoindentation studies show the Cu ball bond is harder in regions with Pd. - Abstract: The Pd plating on the 20 μm Cu wire dissolves in the free air ball (FAB) and the Cu ball bond during the wire bonding process without forming intermetallic compounds. The limiting supply of Pd and the short bonding process, 15 ms of thermosonic bonding, result in uneven distribution of Pd in the as produced Cu ball bond. Also, the Pd-rich phase may accompany small voids formed within the FAB and the wire bond, and following the direction of semi-solid Cu flow. The Pd distribution, as evidenced by the focused ion beam (FIB) and wavelength dispersive X-ray spectroscopy (WDS) mapping, reveals the whirlpool flow pattern of Cu within the FAB and the ball bond. Pd distributes within the copper ball through convective transport by the copper flow. Additionally, hardness measurements by nanoindentation testing show that the Cu ball bond is harder in the regions where Pd exists.
Room-temperature-processed flexible n-InGaZnO/p-Cu2O heterojunction diodes and high-frequency diode rectifiers

International Nuclear Information System (INIS)

Chen, Wei-Chung; Hsu, Po-Ching; Chien, Chih-Wei; Chang, Kuei-Ming; Hsu, Chao-Jui; Chang, Ching-Hsiang; Lee, Wei-Kai; Chou, Wen-Fang; Wu, Chung-Chih; Hsieh, Hsing-Hung

2014-01-01

In this work, we report successful implementation of room-temperature-processed flexible n-InGaZnO/p-Cu 2 O heterojunction diodes on polyethylene naphthalate (PEN) plastic substrates using the sputtering technique. Using n-type InGaZnO and p-type Cu 2 O films deposited by sputtering at room temperature, flexible n-InGaZnO/p-Cu 2 O heterojunction diodes were successfully fabricated on PEN plastic substrates. The didoes on PEN substrates exhibited a low apparent turn-on voltage of 0.44 V, a high rectification ratio of up to 3.4 × 10 4 at ±1.2 V, a high forward current of 1 A cm −2 around 1 V and a decent ideality factor of 1.4, similar to the characteristics of n-InGaZnO/p-Cu 2 O diodes fabricated on glass substrates. The characterization of the frequency response of the room-temperature-processed flexible n-InGaZnO/p-Cu 2 O heterojunction diode rectifiers indicated that they are capable of high-frequency operation up to 27 MHz, sufficient for high-frequency (13.56 MHz) applications. Preliminary bending tests on diode characteristics and rectifier frequency responses indicate their promise for applications in flexible electronics. (paper)
Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

Energy Technology Data Exchange (ETDEWEB)

Benoved, Nir [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada)

2009-09-05

Air plasma spraying has been used to produce porous composite anodes based on Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9} (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H{sub 2}, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 {omega} cm{sup 2} in impedance tests in hydrogen at 712 C. (author)
Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

Science.gov (United States)

Benoved, Nir; Kesler, O.

Air plasma spraying has been used to produce porous composite anodes based on Ce 0.8Sm 0.2O 1.9 (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H 2, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 Ω cm 2 in impedance tests in hydrogen at 712 °C.
Epitaxial growth of Cu on Cu(001): Experiments and simulations

International Nuclear Information System (INIS)

Furman, Itay; Biham, Ofer; Zuo, Jiang-Kai; Swan, Anna K.; Wendelken, John

2000-01-01

A quantitative comparison between experimental and Monte Carlo simulation results for the epitaxial growth of Cu/Cu(001) in the submonolayer regime is presented. The simulations take into account a complete set of hopping processes whose activation energies are derived from semiempirical calculations using the embedded-atom method. The island separation is measured as a function of the incoming flux and the temperature. A good quantitative agreement between the experiment and simulation is found for the island separation, the activation energies for the dominant processes, and the exponents that characterize the growth. The simulation results are then analyzed at lower coverages, which are not accessible experimentally, providing good agreement with theoretical predictions as well
Effects of advanced process approaches on electromigration degradation of Cu on-chip interconnects

Energy Technology Data Exchange (ETDEWEB)

Meyer, M.A.

2007-07-12

This thesis provides a methodology for the investigation of electromigration (EM) in Cu-based interconnects. An experimental framework based on in-situ scanning electron microscopy (SEM) investigations was developed for that purpose. It is capable to visualize the EM-induced void formation and evolution in multi-level test structures in real time. Different types of interconnects were investigated. Furthermore, stressed and unstressed samples were studied applying advanced physical analysis techniques in order to obtain additional information about the microstructure of the interconnects as well as interfaces and grain boundaries. These data were correlated to the observed degradation phenomena. Correlations of the experimental results to recently established theoretical models were highlighted. Three types of Cu-based interconnects were studied. Pure Cu interconnects were compared to Al-alloyed (CuAl) and CoWP-coated interconnects. The latter two represent potential approaches that address EM-related reliability concerns. It was found that in such interconnects the dominant diffusion path is no longer the Cu/capping layer interface for interconnects as in pure Cu interconnects. Instead, void nucleation occurs at the bottom Cu/barrier interface with significant effects from grain boundaries. Moreover, the in-situ investigations revealed that the initial void nucleation does not occur at the cathode end of the lines but several micrometers away from it. The mean times-to-failure of CuAl and CoWP-coated interconnects were increased by at least one order of magnitude compared to Cu interconnects. The improvements were attributed to the presence of foreign metal atoms at the Cu/capping layer interface. Post-mortem EBSD investigations were used to reveal the microstructure of the tested samples. The data were correlated to the in-situ observations. (orig.)
Phase evolution and thermal stability of 2 Mg–Cu alloys processed by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Martínez, C., E-mail: carola.martinezu@usach.cl [Departamento de Ingeniería Metalúrgica, Facultad de Ingeniería, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 10233, Santiago (Chile); Ordoñez, S., E-mail: stella.ordonez@usach.cl [Departamento de Ingeniería Metalúrgica, Facultad de Ingeniería, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 10233, Santiago (Chile); Guzmán, D. [Departamento de Ingeniería en Metalurgia, Facultad de Ingeniería, Universidad de Atacama y CRIDESAT, Av. Copayapu 485, Casilla de Correo 240, Copiapó (Chile); Serafini, D. [Departamento de Física, Facultad de Ciencia, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 307, Santiago (Chile); Iturriza, I. [CEIT, Manuel de Lardizábal 15, 20018 San Sebastián, España (Spain); Bustos, O. [Departamento de Ingeniería Metalúrgica, Facultad de Ingeniería, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 10233, Santiago (Chile)

2013-12-25

Highlights: •Study of phase evolution of elemental powders Mg and Cu by mechanical alloying. •The presence of an amorphous precursor which crystallizes to Mg{sub 2}Cu can be observed. •Establishing the sequence of phase transformations leading to the formation of Mg{sub 2}Cu. •The feasibility to obtain Mg{sub 2}Cu by means two possible routes has been established. -- Abstract: Phase evolution during mechanical alloying (MA) of elemental Mg and Cu powders and their subsequent heat treatment is studied. Elemental Mg and Cu powders in a 2:1 atomic ratio were mechanically alloyed in a SPEX 8000D mill using a 10:1 ball-to-powder ratio. X-ray diffraction (XRD) shows that the formation of the intermetallic Mg{sub 2}Cu takes place between 3 and 4 h of milling, although traces of elemental Cu are still present after 10 h of milling. The thermal behavior of different powder mixtures was evaluated by differential scanning calorimetry (DSC). The combination of DSC, heat treatment and XRD has shown a sequence of phase transformations that results in the intermetallic Mg{sub 2}Cu from an amorphous precursor. This amorphous phase is converted into Mg{sub 2}Cu by heating at low temperature (407 K). Short MA times and the formation of the amorphous precursor, together with its subsequent transformation into Mg{sub 2}Cu at low temperatures; represent an advantageous alternative route for its preparation.
Functional Roles of Neural Preparatory Processes in a Cued Stroop Task Revealed by Linking Electrophysiology with Behavioral Performance.

Directory of Open Access Journals (Sweden)

Chao Wang

Full Text Available It is well established that cuing facilitates behavioral performance and that different aspects of instructional cues evoke specific neural preparatory processes in cued task-switching paradigms. To deduce the functional role of these neural preparatory processes the majority of studies vary aspects of the experimental paradigm and describe how these variations alter markers of neural preparatory processes. Although these studies provide important insights, they also have notable limitations, particularly in terms of understanding the causal or functional relationship of neural markers to cognitive and behavioral processes. In this study, we sought to address these limitations and uncover the functional roles of neural processes by examining how variability in the amplitude of neural preparatory processes predicts behavioral performance to subsequent stimuli. To achieve this objective 16 young adults were recruited to perform a cued Stroop task while their brain activity was measured using high-density electroencephalography. Four temporally overlapping but functionally and topographically distinct cue-triggered event related potentials (ERPs were identified: 1 A left-frontotemporal negativity (250-700 ms that was positively associated with word-reading performance; 2 a midline-frontal negativity (450-800 ms that was positively associated with color-naming and incongruent performance; 3 a left-frontal negativity (450-800 ms that was positively associated with switch trial performance; and 4 a centroparietal positivity (450-800 ms that was positively associated with performance for almost all trial types. These results suggest that at least four dissociable cognitive processes are evoked by instructional cues in the present task, including: 1 domain-specific task facilitation; 2 switch-specific task-set reconfiguration; 3 preparation for response conflict; and 4 proactive attentional control. Examining the relationship between ERPs and behavioral
Functional Roles of Neural Preparatory Processes in a Cued Stroop Task Revealed by Linking Electrophysiology with Behavioral Performance.

Science.gov (United States)

Wang, Chao; Ding, Mingzhou; Kluger, Benzi M

2015-01-01

It is well established that cuing facilitates behavioral performance and that different aspects of instructional cues evoke specific neural preparatory processes in cued task-switching paradigms. To deduce the functional role of these neural preparatory processes the majority of studies vary aspects of the experimental paradigm and describe how these variations alter markers of neural preparatory processes. Although these studies provide important insights, they also have notable limitations, particularly in terms of understanding the causal or functional relationship of neural markers to cognitive and behavioral processes. In this study, we sought to address these limitations and uncover the functional roles of neural processes by examining how variability in the amplitude of neural preparatory processes predicts behavioral performance to subsequent stimuli. To achieve this objective 16 young adults were recruited to perform a cued Stroop task while their brain activity was measured using high-density electroencephalography. Four temporally overlapping but functionally and topographically distinct cue-triggered event related potentials (ERPs) were identified: 1) A left-frontotemporal negativity (250-700 ms) that was positively associated with word-reading performance; 2) a midline-frontal negativity (450-800 ms) that was positively associated with color-naming and incongruent performance; 3) a left-frontal negativity (450-800 ms) that was positively associated with switch trial performance; and 4) a centroparietal positivity (450-800 ms) that was positively associated with performance for almost all trial types. These results suggest that at least four dissociable cognitive processes are evoked by instructional cues in the present task, including: 1) domain-specific task facilitation; 2) switch-specific task-set reconfiguration; 3) preparation for response conflict; and 4) proactive attentional control. Examining the relationship between ERPs and behavioral
Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers Processed from Aqueous Precursor Solutions and Their Application in Thin-Film Transistors and Highly Efficient Organic and Organometal Halide Perovskite Solar Cells

KAUST Repository

Wijeyasinghe, Nilushi

2017-07-28

This study reports the development of copper(I) thiocyanate (CuSCN) hole-transport layers (HTLs) processed from aqueous ammonia as a novel alternative to conventional n-alkyl sulfide solvents. Wide bandgap (3.4–3.9 eV) and ultrathin (3–5 nm) layers of CuSCN are formed when the aqueous CuSCN–ammine complex solution is spin-cast in air and annealed at 100 °C. X-ray photoelectron spectroscopy confirms the high compositional purity of the formed CuSCN layers, while the high-resolution valence band spectra agree with first-principles calculations. Study of the hole-transport properties using field-effect transistor measurements reveals that the aqueous-processed CuSCN layers exhibit a fivefold higher hole mobility than films processed from diethyl sulfide solutions with the maximum values approaching 0.1 cm2 V−1 s−1. A further interesting characteristic is the low surface roughness of the resulting CuSCN layers, which in the case of solar cells helps to planarize the indium tin oxide anode. Organic bulk heterojunction and planar organometal halide perovskite solar cells based on aqueous-processed CuSCN HTLs yield power conversion efficiency of 10.7% and 17.5%, respectively. Importantly, aqueous-processed CuSCN-based cells consistently outperform devices based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate HTLs. This is the first report on CuSCN films and devices processed via an aqueous-based synthetic route that is compatible with high-throughput manufacturing and paves the way for further developments.
Kinetics of photocurrent generation and an efficient charge separation of a dye-sensitized n-Cu2O/p-CuSCN junction photoelectrode in a solid-state photovoltaic cell

International Nuclear Information System (INIS)

Fernando, C A N; Kumara, N T R N; Gamage, T N

2010-01-01

A Cu/n-Cu 2 O/dye/p-CuSCN junction photoelectrode is fabricated to produce a solid-state dye-sensitized photovoltaic cell. Samples are characterized by XRD, SEM and surface resistivity measurements. Photocurrent generation is found due to light absorption of n-Cu 2 O thin film and dye sensitization between p-CuSCN and the dye. Kinetics of the photocurrent generation of the dye sensitization is studied solving the rate equations by the iteration method obtaining a relationship for the photocurrent quantum efficiency (Φ) depending on the surface concentration (D o ) of the dye and the rate constants of the reactions with connection to the dye sensitization process. The solution obtained in the steady state by iteration is found to be of the form Φ = AD o −BD o 2 (A and B are constants related to the reaction rates of the photocurrent generation process and the concentration of the n-Cu 2 O film). The variation of the n-Cu 2 O concentration with photocurrent is presented. A photocurrent enhancement is observed for the Cu/n-Cu 2 O/dye/p-CuSCN photovoltaic cell compared to that of Cu/n-Cu 2 O, Cu/p-CuSCN/dye and Cu/n-Cu 2 O/p-CuSCN photovoltaic cells. Good rectification characteristics are observed for the Cu/n-Cu 2 O/p-CuSCN photoelectrode compared to that of Cu/n-Cu 2 O and Cu/p-CuSCN photoelectrodes. Photocurrent enhancement is found due to the efficient charge separation process at the n–p junction. Energy band structures of the n–p junction are proposed according to the onset potentials which are used to discuss the mechanism of the efficient charge separation suppressing the recombination process

Visible-light photocatalytic decolorization of reactive brilliant red X-3B on Cu{sub 2}O/crosslinked-chitosan nanocomposites prepared via one step process

Energy Technology Data Exchange (ETDEWEB)

Cao, Chunhua [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@yahoo.cn [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Liu, Li; Zhu, Huayue [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua; Gao, Lin [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China)

2013-04-15

Cu{sub 2}O/crosslinked-chitosan nanocomposites (Cu{sub 2}O/CS NCs) were in situ prepared via a simple one-step liquid phase precipitation–reduction process and characterized by XRD, FT-IR, SEM, TEM, BET, XPS and UV–vis/DRS. The characterization results showed that Cu{sub 2}O/CS NCs were almost similar spherical or ellipsoidal and the surface was rough and porous because Cu{sub 2}O particle was wrapped in chitosan. The chitosan layer was especially favorable for improving the adsorption ability of dye and molecular oxygen and restraining the recombination of electrons–holes pair. The visible-light photocatalytic decolorization behavior on Cu{sub 2}O/CS NCs was evaluated using reactive brilliant red X-3B (X-3B) as a model pollutant. The influences of various experimental factors on X-3B decolorization were investigated. It was found that the photocatalytic decolorization process on Cu{sub 2}O/CS NCs followed apparent pseudo-first-order kinetics model. The dye X-3B could be decolorized more efficiently in acidic media than in alkaline media. Cu{sub 2}O/CS NCs exhibited enhanced visible-light photocatalytic activity compared with other photocatalysts reported before under similar experimental conditions.
A novel nonenzymatic amperometric hydrogen peroxide sensor based on CuO@Cu2O nanowires embedded into poly(vinyl alcohol).

Science.gov (United States)

Chirizzi, Daniela; Guascito, Maria Rachele; Filippo, Emanuela; Tepore, Antonio

2016-01-15

A new, very simple, rapid and inexpensive nonenzymatic amperometric sensor for hydrogen peroxide (H2O2) detection is proposed. It is based on the immobilization of cupric/cuprous oxide core shell nanowires (CuO@Cu2O-NWs) in a poly(vinyl alcohol) (PVA) matrix directly drop casted on a glassy carbon electrode surface to make a CuO@Cu2O core shell like NWs PVA embedded (CuO@Cu2O-NWs/PVA) sensor. CuO nanowires with mean diameters of 120-170nm and length in the range 2-5μm were grown by a simple catalyst-free thermal oxidation process based on resistive heating of pure copper wires at ambient conditions. The oxidation process of the copper wire surface led to the formation of a three layered structure: a thick Cu2O bottom layer, a CuO thin intermediate layer and CuO nanowires. CuO nanowires were carefully scratched from Cu2O layer with a sharp knife, dispersed into ethanol and sonicated. Then, the NWs were embedded in PVA matrix. The morphological and spectroscopic characterization of synthesized CuO-NWs and CuO@Cu2O-NWs/PVA were performed by transmission electron microscopy (TEM), selected area diffraction pattern (SAD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. Moreover a complete electrochemical characterization of these new CuO@Cu2O-NWs/PVA modified glassy carbon electrodes was performed by Cyclic Voltammetry (CV) and Cronoamperometry (CA) in phosphate buffer (pH=7; I=0.2) to investigate the sensing properties of this material against H2O2. The electrochemical performances of proposed sensors as high sensitivity, fast response, reproducibility and selectivity make them suitable for the quantitative determination of hydrogen peroxide substrate in batch analysis. Copyright © 2015 Elsevier B.V. All rights reserved.
Low energy positron diffraction from Cu(111): Importance of surface loss processes at large angles of incidence

International Nuclear Information System (INIS)

Lessor, D.L.; Duke, C.B.; Lippel, P.H.; Brandes, G.R.; Canter, K.F.; Horsky, T.N.

1990-10-01

Intensities of positrons specularly diffracted from Cu(111) were measured at the Brandeis positron beam facility and analyzed in the energy range 8eV i = 4eV. At lower energies strong energy dependences occur associated both with multiple elastic scattering phenomena within atomic layers of Cu parallel to the surface and with the thresholds of inelastic channels (e.g., plasmon creation). Use of the free electron calculation of V i shows that energy dependence of inelastic processes is necessary to obtain a satisfactory description of the absolute magnitude of the diffracted intensities below E = 50eV. Detailed comparison of the calculated and observed diffraction intensities reveals the necessity of incorporating surface loss processes explicitly into the model in order to achieve a quantitative description of the measured intensities for E 40 degree. 30 refs., 5 figs., 1 tab
Synthesis of Ag-Cu and Ag-Cu{sub 2}O alloy nanoparticles using a seed-mediated polyol process, thermodynamic and kinetic aspects

Energy Technology Data Exchange (ETDEWEB)

Niknafs, Yasaman; Amirjani, Amirmostafa; Marashi, Pirooz, E-mail: pmarashi@aut.ac.ir; Fatmehsari, Davoud Haghshenas

2017-03-01

In this paper, Ag, Ag-Cu and Ag-Cu{sub 2}O nanoparticles were synthesized using a modified polyol method. Size, shape and composition of the obtained nanostructures were effectively controlled by adjusting the kinetic and thermodynamic conditions. Response surface methodology was employed to consider the interaction of parameters and to develop a polynomial equation for predicting the size of the silver nanoparticles. The precisely controlled silver nanoaprticles were used as the seeds for the formation of alloyed nanoparticles. By manipulating the involved parameters, both spherical and cubical Ag-Cu and Ag-Cu{sub 2}O nanostructures are obtainable in the size range of 90–100 nm. The morphological, optical and compositional characteristics of the obtained nanostructures were studied using SEM, FE-SEM, UV–Vis, EDS and XRD. - Highlights: • Synthesis of Ag, Ag-Cu and Ag-Cu{sub 2}O alloy nanostructures. • RSM was successfully employed for predicting the size of the AgNPs. • Size and composition tuning by adjusting the kinetic and thermodynamic conditions.
Facile synthesis of dendritic Cu by electroless reaction of Cu-Al alloys in multiphase solution

Energy Technology Data Exchange (ETDEWEB)

Wang, Ying; Liang, Shuhua, E-mail: liangxaut@gmail.com; Yang, Qing; Wang, Xianhui

2016-11-30

Highlights: • Nano- or micro-scale fractal dendritic copper (FDC) was synthesized by electroless immersing of Cu-Al alloys in CuCl{sub 2} + HCl. • FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl{sub 2} + HCl solution. • Nanoscale Cu{sub 2}O was found at the edge of FDC. Nanoporous copper (NPC) can also be obtained by using Cu{sub 17}Al{sub 83} alloy. • The potential difference between CuAl{sub 2} and α-Al phase and the replacement reaction in multiphase solution are key factors. - Abstract: Two-dimensional nano- or micro-scale fractal dendritic coppers (FDCs) were synthesized by electroless immersing of Cu-Al alloys in hydrochloric acid solution containing copper chloride without any assistance of template or surfactant. The FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl{sub 2} + HCl solution. Compared to Cu{sub 40}Al{sub 60} and Cu{sub 45}Al{sub 55} alloys, the FDC shows hierarchical distribution and homogeneous structures using Cu{sub 17}Al{sub 83} alloy as the starting alloy. The growth direction of the FDC is <110>, and all angles between the trunks and branches are 60°. Nanoscale Cu{sub 2}O was found at the edge of FDC. Interestingly, nanoporous copper (NPC) can also be obtained through Cu{sub 17}Al{sub 83} alloy. Studies showed that the formation of FDC depended on two key factors: the potential difference between CuAl{sub 2} intermetallic and α-Al phase of dual-phase Cu-Al alloys; a replacement reaction that usually occurs in multiphase solution. The electrochemical experiment further proved that the multi-branch dendritic structure is very beneficial to the proton transfer in the process of catalyzing methanol.
Processing of single- and multi-domain YBa2Cu3Ox bulk materials for levitation applications by Nd1+xBa2-xCu3Oy seeding

International Nuclear Information System (INIS)

Todt, V.R.

1995-01-01

Melt processing of YBa 2 Cu 3 O x (Y123) is a well established technique to produce materials for levitation applications. We report our new results on the melt-processing of Y123. To achieve materials with high levitation forces we utilize a seeding technique using Nd 1+x Ba 2-x Cu 3 O y- seeds (Nd123). Two different kinds of Nd13-seeds, one plate-shaped and the other cube-shaped, were developed and used for this study. The microstructures of the levitators depended strongly on the type of the seeding material used and on the seeding geometry. We were able to produce large single domains as well as materials containing five domains with three different c-axis orientations. Levitation forces up to 8.2 N for samples with a diameter of about 18 mm were found for the multi-domain samples, which is well within the area of the levitation forces measured for the single domain materials
Microstructure And Mechanical Properties Of An Al-Zn-Mg-Cu Alloy Produced By Gravity Casting Process

Directory of Open Access Journals (Sweden)

Saikawa S.

2015-06-01

Full Text Available High-strength aluminum alloy are widely used for structural components in aerospace, transportation and racing car applications. The objective of this study is to enhance the strength of the Al-Zn-Mg-Cu alloy used for gravity casting process. All alloys cast into stepped-form sand mold (Sand-mold Casting; SC and Y-block shaped metal mold(Permanent mold Casting; PC C and then two –step aged at 398-423 K after solution treated at 743 K for 36 ks. The tensile strength and total elongation of the two-step aged SC alloys were 353-387 MPa and about 0.4% respectively. This low tensile properties of the SC alloys might be caused by remaining of undissolved crystallized phase such as Al2CuM, MgZn2 and Al-Fe-Cu system compounds. However, good tensile properties were obtained from PC alloys, tensile strength and 0.2% proof stress and elongation were 503-537 MPa, 474-519 MPa and 1.3-3.3%.
The mechanism of degradation of bisphenol A using the magnetically separable CuFe{sub 2}O{sub 4}/peroxymonosulfate heterogeneous oxidation process

Energy Technology Data Exchange (ETDEWEB)

Xu, Yin; Ai, Jia [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Shenzhen Research Institute of Wuhan University, Shenzhen 518057 (China); Zhang, Hui, E-mail: eeng@whu.edu.cn [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Shenzhen Research Institute of Wuhan University, Shenzhen 518057 (China)

2016-05-15

Highlights: • Copper ferrite (CuFe{sub 2}O{sub 4}) was fabricated and utilized in heterogeneous PMS process. • The influence of reaction parameters for the mineralization of BPA were evaluated. • Possible reaction mechanism and the stability of CuFe{sub 2}O{sub 4} were investigated. • Surface bound radicals (mainly ·OH) may be responsible for the BPA degradation. - Abstract: The removal of bisphenol A (BPA) in aqueous solution by an oxidation process involving peroxymonosulfate (PMS) activated by CuFe{sub 2}O{sub 4} magnetic nanoparticles (MNPs) is reported herein. The effects of PMS concentration, CuFe{sub 2}O{sub 4} dosage, initial pH, initial BPA concentration, catalyst addition mode, and anions (Cl{sup −}, F{sup −}, ClO{sub 4}{sup −} and H{sub 2}PO{sub 4}{sup −}) on BPA degradation were investigated. Results indicate that nearly complete removal of BPA (50 mg/L) within 60 min and 84.0% TOC removal in 120 min could be achieved at neutral pH by using 0.6 g/L CuFe{sub 2}O{sub 4} MNPs and 0.3 g/L PMS. The generation of reactive radicals (mainly hydroxyl radicals) was confirmed using electron paramagnetic resonance (EPR). Possible mechanisms on the radical generation from CuFe{sub 2}O{sub 4}/PMS system are proposed based on the results of radical identification tests and XPS analysis. The lack of inhibition of the reaction by free radical scavengers such as methanol and tert-butyl alcohol suggests that these species may not be generated in the bulk solution, and methylene blue probe experiments confirm that this process does not involve free radical generation. Surface-bound, rather than free radicals generated by a surface catalyzed-redox cycle involving both Fe(III) and Cu(II), are postulated to be responsible for the mineralization of bisphenol A.
CuGaS2 and CuGaS2–ZnS Porous Layers from Solution-Processed Nanocrystals

Science.gov (United States)

Guardia, Pablo; Estradé, Sònia; Peiró, Francesca; Cabot, Andreu

2018-01-01

The manufacturing of semiconducting films using solution-based approaches is considered a low cost alternative to vacuum-based thin film deposition strategies. An additional advantage of solution processing methods is the possibility to control the layer nano/microstructure. Here, we detail the production of mesoporous CuGaS2 (CGS) and ZnS layers from spin-coating and subsequent cross-linking through chalcogen-chalcogen bonds of properly functionalized nanocrystals (NCs). We further produce NC-based porous CGS/ZnS bilayers and NC-based CGS–ZnS composite layers using the same strategy. Photoelectrochemical measurements are used to demonstrate the efficacy of porous layers, and particularly the CGS/ZnS bilayers, for improved current densities and photoresponses relative to denser films deposited from as-produced NCs. PMID:29621198
A buffer bridge process for growing multiple YBa2Cu3O7-y grains from one top seed

International Nuclear Information System (INIS)

Lee, J-H; Park, S-D; Jun, B-H; Lee, J S; Kim, C-J; Han, S C; Han, Y H

2011-01-01

This study presents a buffer bridge process that allows growing multiple YBa 2 Cu 3 O 7-y (Y123) grains from one top seed. This process uses a buffer bridge pellet (Y 2 BaCuO 5 or Y123) to deliver the Y123 growth from one seed to several Y123 compacts. The top seeded melt growth (TSMG) process combined with the buffer bridge process facilitated the fabrication of several single-grained Y123 superconductors using one seed. In addition to achieving the growth of multiple Y123 grains, this process ensured a uniform distribution of superconducting properties of the top surface because the seed/compact interface area (the number of seeds), which is the route for the impurities from the seeds, was minimized. Additionally, the impurity contamination from a seed was considerably suppressed using a buffer pellet. One (110) diagonal facet line, as a result of the corner-to-corner growth, developed on the top surfaces of the prepared Y123 compacts, which is comparable to the x-like facet line of the conventional TSMG processed samples. The trapped magnetic field (H) profiles at 77 K of the prepared Y123 compacts, which were estimated using an Nd-B-Fe permanent magnet, showed the H contour map of a single-grain mode. The force-distance curves for the field cooled and zero-field cooled Y123 compacts at 77 K showed high and reliable levitation forces with a small deviation among compacts. The buffer bridge process can be applied to a batch process for the mass production of single-grain REBa 2 Cu 3 O 7-y (RE: rare-earth elements) superconductors with uniform top surface properties.
Hole-transporting transistors and circuits based on the transparent inorganic semiconductor copper(I) thiocyanate (CuSCN) processed from solution at room temperature

KAUST Repository

Pattanasattayavong, Pichaya

2012-12-27

The wide bandgap and highly transparent inorganic compound copper(I) thiocyanate (CuSCN) is used for the first time to fabricate p-type thin-film transistors processed from solution at room temperature. By combining CuSCN with the high-k relaxor ferroelectric polymeric dielectric P(VDF-TrFE-CFE), we demonstrate low-voltage transistors with hole mobilities on the order of 0.1 cm2 V-1 s-1. By integrating two CuSCN transistors, unipolar logic NOT gates are also demonstrated. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Comparison of Two Powder Processing Techniques on the Properties of Cu-NbC Composites

Directory of Open Access Journals (Sweden)

B. D. Long

2014-01-01

Full Text Available An in situ Cu-NbC composite was successfully synthesized from Cu, Nb, and C powders using ball milling and high pressure torsion (HPT techniques. The novelty of the new approach, HPT, is the combination of high compaction pressure and large shear strain to simultaneously refine, synthesize, and consolidate composite powders at room temperature. The HPTed Cu-NbC composite was formed within a short duration of 20 min without Fe contamination from the HPT’s die. High porosity of 3–9%, Fe and niobium oxidations, from grinding media and ethanol during ball milling led to low electrical conductivity of the milled Cu-NbC composite. The electrical conductivity of the HPTed Cu-NbC composite showed a value 50% higher than that of milled Cu-NbC composite of the same composition.
Preparation of Cu2Sn3S7 Thin-Film Using a Three-Step Bake-Sulfurization-Sintering Process and Film Characterization

Directory of Open Access Journals (Sweden)

Tai-Hsiang Lui

2015-01-01

Full Text Available Cu2Sn3S7 (CTS can be used as the light absorbing layer for thin-film solar cells due to its good optical properties. In this research, the powder, baking, sulfur, and sintering (PBSS process was used instead of vacuum sputtering or electrochemical preparation to form CTS. During sintering, Cu and Sn powders mixed in stoichiometric ratio were coated to form the thin-film precursor. It was sulfurized in a sulfur atmosphere to form CTS. The CTS film metallurgy mechanism was investigated. After sintering at 500°C, the thin film formed the Cu2Sn3S7 phase and no impurity phase, improving its energy band gap. The interface of CTS film is continuous and the formation of intermetallic compound layer can increase the carrier concentration and mobility. Therefore, PBSS process prepared CTS can potentially be used as a solar cell absorption layer.
Gas atomization of Cu-modified AB5 metal hydride alloys

International Nuclear Information System (INIS)

Young, K.; Ouchi, T.; Banik, A.; Koch, J.; Fetcenko, M.A.; Bendersky, L.A.; Wang, K.; Vaudin, M.

2011-01-01

Research highlights: → The gas atomization process together with a hydrogen annealing process was demonstrated on AB5 alloys. → The method was found to be effective in restoring the original cycle life sacrificed by the incorporation of copper in the alloy formula as a means of improving the low temperature performance of AB 5 alloys. → The new process also improves high rate, low temperature, and charge retention performances for both Cu-free and Cu-containing AB 5 alloys. - Abstract: Gas atomization together with a hydrogen annealing process has been proposed as a method to achieve improved low-temperature performance of AB 5 alloy electrodes in Ni/MH batteries and restore the original cycle life which was sacrificed by the incorporation of copper in the alloy formula. While the gas atomization process reduces the lattice constant aspect ratio c/a of the Cu-containing alloys, the addition of a hydrogen annealing step recovers this property, although it is still inferior to the conventionally prepared annealed Cu-free alloy. This observation correlates very well with the cycle life performance. In addition to extending the cycle life of the Cu-containing metal hydride electrode, processing by gas atomization with additional hydrogen annealing improves high-rate, low-temperature, and charge retention performances for both Cu-free and Cu-containing AB 5 alloys. The degradation mechanisms of alloys made by different processes through cycling are also discussed.
Process of preparing superconductive oxide complexes containing L, Ba, Cu and O and method of using the same

International Nuclear Information System (INIS)

Salama, K.; Selvamanickam, V.

1995-01-01

A superconductor material having a current density, J, of from about 30,000 to about 85,000 amps/cm 2 at zero magnetic field and 77 K is disclosed. The 123 superconductor, of the formula L 1 Ba 2 Cu 3 O 6+δ wherein L is preferably yttrium, is capable of entrapping sufficiently high magnetic fields and exhibits a low microwave surface resistance. The process of preparing the superconductor comprises compacting the bulk product, L 1 Ba 2 Cu 3 O, and then sintering the reaction product at a temperature between about 40 C to about 90 C below its melting point, i.e., for Y 1 Ba 2 Cu 3 O 6+δ at a temperature of approximately 940 C. The composition is then heated in a preheated chamber maintained at approximately 1090 C to about 1,200 C (approximately 1,100 C for Y 1 Ba 2 Cu 3 O 6+δ ) until it has been decomposed, and is then rapidly cooled to a temperature between about 10 C to about 30 C above its melting point, i.e. for Y 1 Ba 2 Cu 3 O 6+δ a temperature of 1,030 C, and then is controlled cooled at a rate of 1 C/hr until it reaches a temperature of about 20 C to about 40 C below its melting point, i.e., for Y 1 Ba 2 Cu 3 O 6+δ a temperature of 980 C. The composition is steadily held at this temperature for at least eight hours, and then cooled to a temperature of approximately 400 C below its melting point (for Y 1 Ba 2 Cu 3 O 6+δ approximately a temperature of 600 C). The material is then slowly cooled by another 200 C and is then annealed in oxygen. 5 figs
Ex Situ and Operando Studies on the Role of Copper in Cu-Promoted SiO2-MgO Catalysts for the Lebedev Ethanol-to-Butadiene Process

NARCIS (Netherlands)

Angelici, Carlo|info:eu-repo/dai/nl/345731506; Meirer, Florian; van der Eerden, Ad M. J.|info:eu-repo/dai/nl/304840483; Schaink, Herrick L.; Goryachev, Andrey; Hofmann, Jan P.|info:eu-repo/dai/nl/355351110; Hensen, Emiel J. M.; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397; Bruijnincx, Pieter C. A.|info:eu-repo/dai/nl/33799529X

2015-01-01

Dehydrogenation promoters greatly enhance the performance of SiO2-MgO catalysts in the Lebedev process. Here, the effect of preparation method and order of addition of Cu on the structure and performance of Cu-promoted SiO2-MgO materials is detailed. Addition of Cu to MgO via incipient wetness
Exploring Cu2O/Cu cermet as a partially inert anode to produce aluminum in a sustainable way

International Nuclear Information System (INIS)

Feng, Li-Chao; Xie, Ning; Shao, Wen-Zhu; Zhen, Liang; Ivanov, V.V.

2014-01-01

Highlights: • Cu 2 O/Cu cermet was used as a candidate partially inert anode material to produce aluminum alloys. • The thermal corrosion behavior of Cu 2 O/Cu was investigated in molten salt at 960 °C. • The corrosion rate is largely governed by the geometrical structures of Cu in the prepared samples. • The corrosion rate increases with decreasing sizes and increasing filling contents of Cu phase. • The corrosion rate was 1.8–9 cm/y and the Cu contents is less than 6.2 wt.% in the produced aluminum. - Abstract: As an energy-intensive process, aluminum production by the Hall–Héroult method accounts for significant emissions of CO 2 and some toxic greenhouse gases. The utilization of an inert anode in place of a carbon anode was considered as a revolutionary technique to solve most of the current environmental problems resulting from the Hall–Héroult process. However, the critical property requirements of the inert anode materials significantly limit the application of this technology. In light of the higher demand for aluminum alloys than for pure aluminum, a partially inert anode was designed to produce aluminum alloys in a more sustainable way. Here, Cu 2 O/Cu cermet was chosen as the material of interest. The thermal corrosion behavior of Cu 2 O/Cu was investigated in Na 3 AlF 6 –CaF 2 –Al 2 O 3 electrolyte at 960 °C to elucidate the corrosion mechanisms of this type of partially inert anode for the production of aluminum or aluminum alloys. Furthermore, the effects of the geometrical structure of the Cu phase on the thermal corrosion behavior of Cu 2 O/Cu cermet in the electrolyte were investigated as well. The thermal corrosion rate was evaluated by the weight loss method and the results show that the samples prepared with branch-like Cu have higher thermal corrosion rate than those prepared with spherical Cu, and the corrosion rate increases with decreasing size and increasing filling content of Cu phase. The calculated corrosion rate
Crystallite-growth, phase transition, magnetic properties, and sintering behaviour of nano-CuFe2O4 powders prepared by a combustion-like process

International Nuclear Information System (INIS)

Köferstein, Roberto; Walther, Till; Hesse, Dietrich; Ebbinghaus, Stefan G.

2014-01-01

The synthesis of nano-crystalline CuFe 2 O 4 powders by a combustion-like process is described herein. Phase formation and evolution of the crystallite size during the decomposition process of a (CuFe 2 )—precursor gel were monitored up to 1000 °C. Phase-pure nano-sized CuFe 2 O 4 powders were obtained after reaction at 750 °C for 2 h resulting in a crystallite size of 36 nm, which increases to 96 nm after calcining at 1000 °C. The activation energy of the crystallite growth process was calculated as 389 kJ mol −1 . The tetragonal⇄cubic phase transition occurs between 402 and 419 °C and the enthalpy change (ΔH) was found to range between 1020 and 1229 J mol −1 depending on the calcination temperature. The optical band gap depends on the calcination temperature and was found between 2.03 and 1.89 eV. The shrinkage and sintering behaviour of compacted powders were examined. Dense ceramic bodies can be obtained either after conventional sintering at 950 °C or after a two-step sintering process at 800 °C. Magnetic measurements of both powders and corresponding ceramic bodies show that the saturation magnetization rises with increasing calcination-/sintering temperature up to 49.1 emu g −1 (2.1 µ B fu −1 ), whereas the coercivity and remanence values decrease. - Graphical abstract: A cheap one-pot synthesis was developed to obtain CuFe 2 O 4 nano-powders with different crystallite sizes (36–96 nm). The optical band gaps, phase transition temperatures and enthalpies were determined depending on the particle size. The sintering behaviour of nano CuFe 2 O 4 was studied in different sintering procedures. The magnetic behaviour of the nano-powders as well as the corresponding ceramic bodies were investigated. - Highlights: • Eco-friendly and simple synthesis for nano CuFe 2 O 4 powder using starch as polymerization agent. • Monitoring the phase evolution and crystallite growth kinetics during the synthesis. • Determination of the optical band gap
Deuterium transport in Cu, CuCrZr, and Cu/Be

Science.gov (United States)

Anderl, R. A.; Hankins, M. R.; Longhurst, G. R.; Pawelko, R. J.

This paper presents the results of deuterium implantation/permeation experiments and TMAP4 simulations for a CuCrZr alloy, for OFHC-Cu and for a Cu/Be bi-layered structure at temperatures from 700 to 800 K. Experiments used a mass-analyzed, 3-keV D 3+ ion beam with particle flux densities of 5 × 10 19 to 7 × 10 19 D/m 2 s. Effective diffusivities and surface molecular recombination coefficients were derived giving Arrhenius pre-exponentials and activation energies for each material: CuCrZr alloy, (2.0 × 10 -2 m 2/s, 1.2 eV) for diffusivity and (2.9 × x10 -14 m 4/s, 1.92 eV) for surface molecular recombination coefficients; OFHC Cu, (2.1 × 10 -6 m 2/s, 0.52 eV) for diffusivity and (9.1 × 10 -18 m 4/s, 0.99 eV) for surface molecular recombination coefficients. TMAP4 simulation of permeation data measured for a Cu/Be bi-layer sample was achieved using a four-layer structure (Cu/BeO interface/Be/BeO back surface) and recommended values for diffusivity and solubility in Be, BeO and Cu.
Thermochemical properties of oxides in Y-Ba-Cu-O, Sr-Bi-O, Cu-Nb-O, Sr-Cu-O, Ca-Cu-O, Cu-O and Hg-Ba-Ca-Cu-O systems

International Nuclear Information System (INIS)

Moiseev, G.K.; Vatolin, N.A.; Il'inykh, N.I.

2000-01-01

Thermochemical properties (ΔH 0 298 , S 0 298 , H 0 298 -H 0 0 , C p (T), C p at T>T melt ) of complex oxides in Y-Ba-Cu-O, Sr-Bi-O, Cu-Nb-O, Sr-Cu-O, Ca-Cu-O, Cu-O and Hg-Ba-Ca-Cu-O systems obtained with application of calculation methods are presented. Nonexperimental methods of estimation, revision and correction of standard formation enthalpies of inorganic compounds are described [ru

Mechanism of via failure in copper/organosilicate glass interconnects induced by oxidation

International Nuclear Information System (INIS)

Min, Woo Sig; Kim, Dong Joon; Pyo, Sung Gyu; Park, Sang Jong; Choi, Jin Tae; Kim, Sibum

2007-01-01

Annealing for copper/organosilicate glass (Cu/OSG) dual damascene (DD) structure resulted in via resistance increase when Ta or TaN x film by ionized physical vapor deposition (iPVD) method was used as a barrier metal. The percentage increase in via resistance was higher in smaller vias. In spite of the huge increase of more than 50% in via resistance during annealing, any Cu voids in a single via or via chains of the DD structure were not observed. Instead, large amount of oxygen was detected at the interface between the barrier metal and Cu in the bottom of the vias. It was found that via resistance increase during annealing was caused by oxidation of the barrier metal at the via bottom. Improvement of the step coverage of the barrier metal inhibited the via resistance increase even after the high temperature annealing at 500 deg. C. It means that the oxygen atoms diffused out from the OSG film were blocked by the barrier metal covering the side wall of the vias
Enhanced photocatalytic, electrochemical and photoelectrochemical properties of TiO2 nanotubes arrays modified with Cu, AgCu and Bi nanoparticles obtained via radiolytic reduction

International Nuclear Information System (INIS)

Nischk, Michał; Mazierski, Paweł; Wei, Zhishun; Siuzdak, Katarzyna; Kouame, Natalie Amoin; Kowalska, Ewa; Remita, Hynd; Zaleska-Medynska, Adriana

2016-01-01

Highlights: • TiO 2 nanotubes were modified with Cu, AgCu, Bi nanoparticles via gamma radiolysis. • Excessive amount of deposited metal decreased photocatalytic activity. • AgCu-modified samples were more active than Cu-modified (with the same Cu content). • AgCu nanoparticles exist in a core (Ag) -shell (Cu) form. • Examined photocatalysts were resistant towards photocorrosion processes. - Abstract: TiO 2 nanotubes arrays (NTs), obtained via electrochemical anodization of Ti foil, were modified with monometallic (Cu, Bi) and bimetallic (AgCu) nanoparticles. Different amounts of metals’ precursors were deposited on the surface of NTs by the spin-coating technique, and the reduction of metals was performed via gamma radiolysis. Surface modification of titania was studied by EDS and XPS analysis. The results show that AgCu nanoparticles exist in a Ag core -Cu shell form. Photocatalytic activity was examined under UV irradiation and phenol was used as a model pollutant of water. Over 95% of phenol degradation was achieved after 60 min of irradiation for almost all examined samples, but only slight difference in degradation efficiency (about 3%) between modified and bare NTs was observed. However, the initial phenol degradation rate and TOC removal efficiency was significantly enhanced for the samples modified with 0.31 and 0.63 mol% of Bi as well as for all the samples modified with Cu and AgCu nanoparticles in comparison with bare titania nanotubes. The saturated photocurrent, under the influence of simulated solar light irradiation, for the most active Bi- and AgCu-modified samples, was over two times higher than for pristine NTs. All the examined materials were resistant towards photocorrosion processes that enables their application for long term processes induced by light.
Instantaneous preparation of CuInSe2 films from elemental In, Cu, Se particles precursor films in a non-vacuum process

International Nuclear Information System (INIS)

Kaigawa, R.; Uesugi, T.; Yoshida, T.; Merdes, S.; Klenk, R.

2009-01-01

CuInSe 2 (CIS) films are successfully prepared by means of non-vacuum, instantaneous, direct synthesis from elemental In, Cu, Se particles precursor films without prior synthesis of CIS nanoparticle precursors and without selenization with H 2 Se or Se vapor. Our precursor films were prepared on metal substrates by spraying the solvent with added elemental In, Cu, and Se particles. Precursor films were instantaneously sintered using a spot welding machine. When the electric power was fixed to 0.6 kVA, elemental In, Cu, or Se peaks were not observed and only peaks of CIS are observed by X-ray diffraction (XRD) on the film sintered for 7/8 s. We can observe XRD peaks indicative of the chalcopyrite-type structure, such as (101), (103) and (211) diffraction peaks. We conclude that the synthesized CIS crystals have chalcopyrite-type structure with high crystallinity
Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

International Nuclear Information System (INIS)

Qu, Jun; He, Xiaoman; Chen, Min; Hu, Huimin; Zhang, Qiwu; Liu, Xinzhong

2017-01-01

In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu_2(OH)_2CO_3) and aluminum hydroxide (Al(OH)_3) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.
Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

Energy Technology Data Exchange (ETDEWEB)

Qu, Jun, E-mail: forsjun@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: zhangqw@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)

2017-04-15

In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.
The fate of sulphur in the Cu-based Chemical Looping with Oxygen Uncoupling (CLOU) Process

International Nuclear Information System (INIS)

Adánez-Rubio, Iñaki; Abad, Alberto; Gayán, Pilar; García-Labiano, Francisco; Diego, Luis F. de; Adánez, Juan

2014-01-01

Highlights: • 15 h of CLOU experiments using lignite were carried out in a continuously unit. • The sulphur split between fuel- and air-reactor streams in the process was analysed. • Most of the sulphur introduced with the fuel exits as SO 2 at the fuel-reactor. • The use of a carbon separation system to reduce the S emission was evaluated. • Coals with high S content can be burnt in a CLOU process with a Cu-based material. - Abstract: The Chemical Looping with Oxygen Uncoupling (CLOU) process is a type of Chemical Looping Combustion (CLC) technology that allows the combustion of solid fuels with air, as with conventional combustion, through the use of oxygen carriers that release gaseous oxygen inside the fuel reactor. The aim of this work was to study the behaviour of the sulphur present in fuel during CLOU combustion. Experiments using lignite as fuel were carried out in a continuously operated 1.5 kW th CLOU unit during more than 15 h. Particles containing 60 wt.% CuO on MgAl 2 O 4 , prepared by spray drying, were used as the oxygen carrier in the CLOU process. The temperature in the fuel reactor varied between 900 and 935 °C. CO 2 capture, combustion efficiency and the sulphur split between fuel and air reactor streams in the process were analysed. Complete combustion of the fuel to CO 2 and H 2 O was found in all experiments. Most of the sulphur introduced with the fuel exited as SO 2 at the fuel reactor outlet, although a small amount of SO 2 was measured at the air reactor outlet. The SO 2 concentration in the air reactor exit flow decreased as the temperature in the fuel reactor increased. A carbon capture efficiency of 97.6% was achieved at 935 °C, with 87.9 wt.% of the total sulphur exiting as SO 2 in the fuel reactor. Both the reactivity and oxygen transport capacity of the oxygen carrier were unaffected during operation with a high sulphur content fuel, and agglomeration problems did not occur. Predictions were calculated regarding the use
Solid state reactions and diffusion processes during rapid thermal processing of Cu-In-S based semiconductors

International Nuclear Information System (INIS)

Enzenhofer, T.

2007-01-01

In this thesis thin layers of the system Cu-In-S were studied for the photovoltaic application by means of structural and electro-optical procedures. The effect of small quantities of group II elements on the absorber and component properties could be explained by a widely appointed study. The motivation to insert extraneous elements into CuInS 2 absorber layers results from the too low zero-current voltage of CuInS 2 based solar cells. It could be shown that by addition of small quantities of Zn and/or Mg ( 2 solar cells aimed efficiencies, which were also determined for the reference system. As limiting factor in the doped system the zero-current has been proved. The intensive analysis of the absorber properties showed the the extraneous atoms effect in the bulk and on the surface different modifications
CuGaS2 and CuGaS2–ZnS Porous Layers from Solution-Processed Nanocrystals

Directory of Open Access Journals (Sweden)

Taisiia Berestok

2018-04-01

Full Text Available The manufacturing of semiconducting films using solution-based approaches is considered a low cost alternative to vacuum-based thin film deposition strategies. An additional advantage of solution processing methods is the possibility to control the layer nano/microstructure. Here, we detail the production of mesoporous CuGaS2 (CGS and ZnS layers from spin-coating and subsequent cross-linking through chalcogen-chalcogen bonds of properly functionalized nanocrystals (NCs. We further produce NC-based porous CGS/ZnS bilayers and NC-based CGS–ZnS composite layers using the same strategy. Photoelectrochemical measurements are used to demonstrate the efficacy of porous layers, and particularly the CGS/ZnS bilayers, for improved current densities and photoresponses relative to denser films deposited from as-produced NCs.
Consolidation of powders of the oxide superconductor YBa/sub 2/Cu/sub 3/Ox by high energy-high rate processing

Energy Technology Data Exchange (ETDEWEB)

Persad, C.; Lee, S.J.; Peterson, D.R.; Swinnea, J.S.; Schmerling, M.

1988-01-01

The consolidation response of powders of the superconducting compound YBa/sub 2/Cu/sub 3/Ox is reported. Copper, silver, tin, and Cu-based metallic glass infiltrates have also been employed in preliminary fabricability studies. The processing approach relies on short-duration (< 1s), high-current-density 10000 A/sq.cm, pulse-resistive heating of powders under applied pressures of 200 MPa to 400 MPa. Powders and fabricated disk compacts were characterized by X-ray diffraction, optical and scanning electron microscopy, and resistivity measurements. X-ray diffraction comparisons of starting powder and consolidated material show retention of the single phase 1-2-3 structure and the development of a preferred orientation. In the consolidated pure YBa/sub 2/Cu/sub 3/0x, Tc onsets of 87K were accompanied by broad transitions. Iodometric analyses indicated oxygen depletion in the as-consolidated disks. Observed oxygen-content profiles across the sample thickness had values 0.11< x <0.35. The variation in the peak processing temperature within the disk was found to correlate with the oxygen content profile.
A first-principles study of the structural, mechanical and electronic properties of precipitates of Al2Cu in Al-Cu alloys.

Science.gov (United States)

Ouyang, Y F; Chen, H M; Tao, X M; Gao, F; Peng, Q; Du, Y

2018-01-03

The properties of precipitates are important in understanding the strengthening mechanism via precipitation during heat treatment and the aging process in Al-Cu based alloys, where the formation of precipitates is sensitive to temperature and pressure. Here we report a first-principles investigation of the effect of temperature and pressure on the structural stability, elastic constants and formation free energy for precipitates of Al 2 Cu, as well as their mechanical properties. Based on the formation enthalpy of Guinier-Preston (GP(I)) zones, the size of the GP(I) zone is predicted to be about 1.4 nm in diameter, which is in good agreement with experimental observations. The formation enthalpies of the precipitates are all negative, suggesting that they are all thermodynamically stable. The present calculations reveal that entropy plays an important role in stabilizing θ-Al 2 Cu compared with θ C '-Al 2 Cu. The formation free energies of θ''-Al 3 Cu, θ C '-Al 2 Cu, θ D '-Al 5 Cu 3 and θ t '-Al 11 Cu 7 increase with temperature, while those of θ'-Al 2 Cu, θ O '-Al 2 Cu and θ-Al 2 Cu decrease. The same trend is observed with the effect of pressure. The calculated elastic constants for the considered precipitation phases indicate that they are all mechanically stable and anisotropic, except θ C '-Al 2 Cu. θ D '-Al 5 Cu 3 has the highest Vicker's hardness. The electronic structures are also calculated to gain insight into the bonding characteristics. The present results can help in understanding the formation of precipitates by different treatment processes.
Friction-stir processing of a high-damping Mn-Cu alloy used for marine propellers

Energy Technology Data Exchange (ETDEWEB)

Lynch, S.P.; Edwards, D.P.; Majumdar, A. [Defence Science and Technology Organisation, Melbourne (Australia); Moutsos, S. [Centre for Advanced Materials Technology, Monash Univ. (Australia); Mahoney, M.W. [Rockwell Scientific, Thousand Oaks (United States)

2003-07-01

Mn-Cu alloys are used for specialised applications, such as marine propellers, where high noise-damping characteristics are required. These alloys tend to have more severe shrinkage porosity than conventional propeller alloys, and the corrosion resistance (including stress-corrosion and corrosion-fatigue resistance) of the alloys is not as high as desirable. Friction-stir processing (FSP) trials on one such alloy (tradename Sonoston) have shown that near-surface porosity can be eliminated and that the coarse, as-cast microstructure can be significantly refined. The corrosion resistance of processed material is substantially improved provided a heat treatment to relieve residual stress is carried out after FSP. (orig.)
Ca doping of TSMTG-YBa2Cu3O7-δ/Y2BaCuO5 composites

International Nuclear Information System (INIS)

Delorme, F.; Harnois, C.; Monot-Laffez, I.; Marinel, S.

2002-01-01

Calcium doped YBa 2 Cu 3 O 7-δ /Y 2 BaCuO 5 bulk samples have been synthesised by the top-seeding-melt-texture growth (TSMTG) process up to 1 wt.% of CaCO 3 . Calcium additions up to 0.25 wt.% of CaCO 3 do not change the decomposition temperature whereas additions of 1 wt.% of CaCO 3 lead to an increase of the decomposition temperature of about 10 deg. C. This difference is not important enough to change the thermal cycle used to process YBa 2 Cu 3 O 7-δ undoped bulk samples. Microstructure studies show that no precursor or secondary phases containing calcium are present in the samples. Energy dispersive spectroscopy analyses have shown that Ca is present both in the YBa 2 Cu 3 O 7-δ matrix and the Y 2 BaCuO 5 particles. The position of the calcium atoms in the superconducting matrix is discussed. The calcium doped samples present slightly depressed critical temperatures but drastically depressed critical current densities
Nanoporous Al sandwich foils using size effect of Al layer thickness during Cu/Al/Cu laminate rolling

Science.gov (United States)

Yu, Hailiang; Lu, Cheng; Tieu, A. Kiet; Li, Huijun; Godbole, Ajit; Kong, Charlie

2018-06-01

The roll bonding technique is one of the most widely used methods to produce metal laminate sheets. Such sheets offer interesting research opportunities for both scientists and engineers. In this paper, we report on an experimental investigation of the 'thickness effect' during laminate rolling for the first time. Using a four-high multifunction rolling mill, Cu/Al/Cu laminate sheets were fabricated with a range of thicknesses (16, 40, 70 and 130 μm) of the Al layer. The thickness of the Cu sheets was a constant 300 μm. After rolling, TEM images show good bonding quality between the Cu and Al layers. However, there are many nanoscale pores in the Al layer. The fraction of nanoscale pores in the Al layer increases with a reduction in the Al layer thickness. The finite element method was used to simulate the Cu/Al/Cu rolling process. The simulation results reveal the effect of the Al layer thickness on the deformation characteristics of the Cu/Al/Cu laminate. Finally, we propose that the size effect of the Al layer thickness during Cu/Al/Cu laminate rolling may offer a method to fabricate 'nanoporous' Al sandwich laminate foils. Such foils can be used in electromagnetic shielding of electrical devices and noisy shielding of building.
Development of brazing process for W-EUROFER joints using Cu-based fillers

Science.gov (United States)

de Prado, J.; Sánchez, M.; Ureña, A.

2016-02-01

A successful joint between W and EUROFER using high temperature brazing technique has been achieved for structural application in future fusion power plants. Cu-based powder alloy mixed with a polymeric binder has been used as filler. Microstructural analysis of the joints revealed that the joint consisted mainly of primary phases and acicular structures in a Cu matrix. Interaction between EUROFER and filler took place at the interface giving rise to several Cu-Ti-Fe rich layers. A loss of hardness at the EUROFER substrate close to the joint due to a diffusion phenomenon during brazing cycle was measured; however, the joints had an adequate shear strength value.
Role of Cu During Sintering of Fe0.96Cu0.04 Nanoparticles

Science.gov (United States)

Sivaprahasam, D.; Sriramamurthy, A. M.; Bysakh, S.; Sundararajan, G.; Chattopadhyay, K.

2018-04-01

Nanoparticle agglomerates of passivated Fe ( n-Fe) and Fe0.96Cu0.04 ( n-Fe0.96Cu0.04), synthesized through the levitational gas condensation (LGC) process, were compacted and sintered using the conventional powder metallurgy method. The n-Fe0.96Cu0.04 agglomerates produced lower green density than n-Fe, and when compacted under pressure beyond 200 MPa, they underwent lateral cracking during ejection attributed to the presence of a passive oxide layer. Sintering under dynamic hydrogen atmosphere can produce a higher density of compact in n-Fe0.96Cu0.04 in comparison to n-Fe. Both the results of dilatometry and thermogravimetric (TG) measurements of the samples under flowing hydrogen revealed enhancement of the sintering process as soon as the reduction of oxide layers could be accomplished. The shrinkage rate of n-Fe0.96Cu0.04 reached a value three times higher than n-Fe at a low temperature of 723 K (450 °C) during heating. This enhanced shrinkage rate was the manifestation of accumulation of Cu at the surface of the particles. The formation of a thin-surface melted layer enriched with copper during heating to isothermal holding facilitated as a medium of transport for diffusion of the elements. The compacts produced by sintering at 773 K (500 °C), with relative density 82 pct, were found to be unstable and oxidized instantly when exposed to ambient atmosphere. The stable compacts of density more than 92 pct with 300- to 450-nm grain size could only be produced when sintering was carried out at 973 K (700 °C) and beyond. The 0.22 wt pct residual oxygen obtained in the sintered compact is similar to what is used for conventional ferrous powder metallurgy products.
Inhibiting properties of benzimidazole films for Cu(II)/Cu(I) reduction in chloride media studied by RDE and EQCN techniques

Energy Technology Data Exchange (ETDEWEB)

Scendo, M. [Institute of Chemistry, Saint Cross Academy, ul. Checinska 5, 25020 Kielce (Poland)]. E-mail: scendo@pu.kielce.pl; Hepel, M. [Department of Chemistry, State University of New York, Potsdam, NY 13676, USA (United States)

2007-08-15

The effects of benzimidazole (BIM) and 2-methylbenzimidazole (MBIM) on the electroreduction of Cu(II) on a rotating Pt disk electrode in chloride media were investigated. These studies were undertaken in conjunction with earlier observation that these imidazole derivatives act as inhibitors of copper corrosion processes and are non-toxic. We have found that BIM and MBIM also form adsorption films on Pt, which are able to inhibit one-electron reduction of Cu(II) to Cu(I) and prevent the development of convective diffusion limiting current wave. The inhibition was found to be controlled by field-assisted mass transfer in the film. The ingress of Cu(II) species into the film was detected using the EQCN technique. The EQCN measurements indicate that small fraction of Cu(I) formed in the film by reduction of Cu(II) is retained in the film, most likely in the form of CuCl. The uptake of CuCl by inhibitor films diminishes in strongly inhibiting films (e.g., in acidic medium). The inhibition effectiveness of Cu(II) reduction process by Pt vertical bar BIM and Pt vertical bar MBIM films increases strongly with increasing acidity of the medium in the pH range from 3.0 to 1.0. The mechanism of this remarkable pH effect has been proposed. It is based on charge and pH-induced film restructuring, including changes in orientation and protonation of BIM molecules in the film.
Enhanced photocatalytic, electrochemical and photoelectrochemical properties of TiO{sub 2} nanotubes arrays modified with Cu, AgCu and Bi nanoparticles obtained via radiolytic reduction

Energy Technology Data Exchange (ETDEWEB)

Nischk, Michał [Department of Chemical Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 G. Narutowicza 11/12 St., 80-233 Gdansk (Poland); Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, 63 Wita Stwosza St., 80-308 Gdansk (Poland); Mazierski, Paweł [Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, 63 Wita Stwosza St., 80-308 Gdansk (Poland); Wei, Zhishun [Institute for Catalysis, Hokkaido University, N21, W10, 001-0021, Sapporo (Japan); Siuzdak, Katarzyna [Centre for Plasma and Laser Engineering, The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, 14 Fiszera St., 80-231 Gdansk (Poland); Kouame, Natalie Amoin [Laboratoire de Chimie Physique, CNRS—UMR 8000,Université Paris-Sud, Université Paris-Saclay, Bâtiment 349, 91405 Orsay (France); Kowalska, Ewa [Institute for Catalysis, Hokkaido University, N21, W10, 001-0021, Sapporo (Japan); Remita, Hynd [Laboratoire de Chimie Physique, CNRS—UMR 8000,Université Paris-Sud, Université Paris-Saclay, Bâtiment 349, 91405 Orsay (France); Zaleska-Medynska, Adriana, E-mail: adriana.zaleska@ug.edu.pl [Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, 63 Wita Stwosza St., 80-308 Gdansk (Poland)

2016-11-30

Highlights: • TiO{sub 2} nanotubes were modified with Cu, AgCu, Bi nanoparticles via gamma radiolysis. • Excessive amount of deposited metal decreased photocatalytic activity. • AgCu-modified samples were more active than Cu-modified (with the same Cu content). • AgCu nanoparticles exist in a core{sub (Ag)}-shell{sub (Cu)} form. • Examined photocatalysts were resistant towards photocorrosion processes. - Abstract: TiO{sub 2} nanotubes arrays (NTs), obtained via electrochemical anodization of Ti foil, were modified with monometallic (Cu, Bi) and bimetallic (AgCu) nanoparticles. Different amounts of metals’ precursors were deposited on the surface of NTs by the spin-coating technique, and the reduction of metals was performed via gamma radiolysis. Surface modification of titania was studied by EDS and XPS analysis. The results show that AgCu nanoparticles exist in a Ag{sub core}-Cu{sub shell} form. Photocatalytic activity was examined under UV irradiation and phenol was used as a model pollutant of water. Over 95% of phenol degradation was achieved after 60 min of irradiation for almost all examined samples, but only slight difference in degradation efficiency (about 3%) between modified and bare NTs was observed. However, the initial phenol degradation rate and TOC removal efficiency was significantly enhanced for the samples modified with 0.31 and 0.63 mol% of Bi as well as for all the samples modified with Cu and AgCu nanoparticles in comparison with bare titania nanotubes. The saturated photocurrent, under the influence of simulated solar light irradiation, for the most active Bi- and AgCu-modified samples, was over two times higher than for pristine NTs. All the examined materials were resistant towards photocorrosion processes that enables their application for long term processes induced by light.
Processing of CuInSe2-Based Solar Cells: Characterization of Deposition Processes in Terms of Chemical Reaction Analyses. Final Report, 6 May 1995 - 31 December 1998

Energy Technology Data Exchange (ETDEWEB)

Anderson, T.J.; Stanbery, B.J.

2001-07-16

This project describes a novel rotating-disc reactor has been designed and built to enable modulated flux deposition of CuInSe2 and its related binary compounds. The reactor incorporates both a thermally activated source and a novel plasma-activated source of selenium vapor, which have been used for the growth of epitaxial and polycrystalline thin-film layers of CuInSe2. A comparison of the different selenium reactant sources has shown evidence of increases in its incorporation when using the plasma source, but no measurable change when the thermally activated source was used. We concluded that the chemical reactivity of selenium vapor from the plasma source is significantly greater than that provided by the other sources studied. Epitaxially grown CuInSe2 layers on GaAs, ZnTe, and SrF2 demonstrate the importance of nucleation effects on the morphology and crystallographic structure of the resulting materials. These studies have resulted in the first reported growth of the CuAu type-I crystallographic polytype of CuInSe2, and the first reported epitaxial growth of CuInSe2 on ZnTe. Polycrystalline binary (Cu,Se) and (In,Se) thin films have been grown, and the molar flux ratio of selenium to metals was varied. It is shown that all of the reported binary compounds in each of the corresponding binary phase fields can be synthesized by the modulated flux deposition technique implemented in the reactor by controlling this ratio and the substrate temperature. These results were employed to deposit bilayer thin films of specific (Cu,Se) and (In,Se) compounds with low melting-point temperature, which were used to verify the feasibility of synthesizing CuInSe2 by subsequent rapid-thermal processing. The studies of the influence of sodium during the initial stages of epitaxy have led to a new model to explain its influences based on the hypothesis that it behaves as a surfactant in the Cu-In-Se material system. This represents the first unified theory on the role of sodium
Effects of deep cryogenic treatment on the solid-state phase transformation of Cu-Al alloy in cooling process

Science.gov (United States)

Wang, Yuhui; Liao, Bo; Liu, Jianhua; Chen, Shuqing; Feng, Yu; Zhang, Yanyan; Zhang, Ruijun

2012-07-01

The solid-state phase transformation temperature and duration of deep cryogenic treated and untreated Cu-Al alloys in cooling process were measured by differential scanning calorimetry measurement. The solid-state phase transformation activation energy and Avrami exponent were calculated according to these measurements. The effects of deep cryogenic treatment on the solid-state phase transformation were investigated based on the measurement and calculation as well as the observation of alloy's microstructure. The results show that deep cryogenic treatment can increase the solid-phase transformation activation energy and shorten the phase transformation duration, which is helpful to the formation of fine grains in Cu-Al alloy.
Growth of intermetallics between Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layered structures

International Nuclear Information System (INIS)

Horváth, Barbara; Illés, Balázs; Shinohara, Tadashi

2014-01-01

Intermetallic growth mechanisms and rates are investigated in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. An 8–10 μm thick Sn surface finish layer was electroplated onto a Cu substrate with a 1.5–2 μm thick Ni or Ag barrier layer. In order to induce intermetallic layer growth, the samples were aged in elevated temperatures: 50 °C and 125 °C. Intermetallic layer growth was checked by focused ion beam–scanning ion microscope. The microstructures and chemical compositions of the intermetallic layers were observed with a transmission electron microscope. It has been found that Ni barrier layers can effectively block the development of Cu 6 Sn 5 intermetallics. The intermetallic growth characteristics in the Sn/Cu and Sn/Ni/Cu systems are very similar. The intermetallic layer grows towards the Sn layer and forms a discrete layer. Differences were observed only in the growth gradients and surface roughness of the intermetallic layer which may explain the different tin whiskering properties. It was observed that the intermetallic layer growth mechanisms are completely different in the Ag barrier layers compared to the Ni layers. In the case of Sn/Ag/Cu systems, the Sn and Cu diffused through the Ag layer, formed Cu 6 Sn 5 intermetallics mainly at the Sn/Ag interface and consumed the Ag barrier layer. - Highlights: • Intermetallic growth was characterised in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. • Intermetallic growth rates and roughness are similar in the Sn/Cu and Sn/Ni/Cu systems. • Sn/Ni/Cu system contains the following intermetallic layer structure Sn–Ni3Sn4–Ni3Sn2–Ni3Sn–Ni. • In the case of Sn/Ag/Cu systems the Sn and Cu diffusion consumes the Ag barrier layer. • When Cu reaches the Sn/Ag interface a large amount of Cu 6 Sn 5 forms above the Ag layer

Thermal storage/discharge performances of Cu-Si alloy for solar thermochemical process

Science.gov (United States)

Gokon, Nobuyuki; Yamaguchi, Tomoya; Cho, Hyun-seok; Bellan, Selvan; Hatamachi, Tsuyoshi; Kodama, Tatsuya

2017-06-01

The present authors (Niigata University, Japan) have developed a tubular reactor system using novel "double-walled" reactor/receiver tubes with carbonate molten-salt thermal storage as a phase change material (PCM) for solar reforming of natural gas and with Al-Si alloy thermal storage as a PCM for solar air receiver to produce high-temperature air. For both of the cases, the high heat capacity and large latent heat (heat of solidification) of the PCM phase circumvents the rapid temperature change of the reactor/receiver tubes at high temperatures under variable and uncontinuous characteristics of solar radiation. In this study, we examined cyclic properties of thermal storage/discharge for Cu-Si alloy in air stream in order to evaluate a potentiality of Cu-Si alloy as a PCM thermal storage material. Temperature-increasing performances of Cu-Si alloy are measured during thermal storage (or heat-charge) mode and during cooling (or heat-discharge) mode. A oxidation state of the Cu-Si alloy after the cyclic reaction was evaluated by using electron probe micro analyzer (EPMA).
Preparation of three-dimensional porous Cu film supported on Cu foam and its electrocatalytic performance for hydrazine electrooxidation in alkaline medium

International Nuclear Information System (INIS)

Liu, Ran; Ye, Ke; Gao, Yinyi; Long, Ziyao; Cheng, Kui; Zhang, Wenping; Wang, Guiling; Cao, Dianxue

2016-01-01

Highlights: • A binder-free Cu/Cu foam electrode is prepared by an electrochemical method. • The electrode owns a novel three-dimensional porous structure. • The electrode exhibits superior catalytic activity for hydrazine electrooxidation. - Abstract: A three-dimensional porous copper film is directly deposited on Cu foam by an electrodeposition method using hydrogen bubbles as dynamic template (denoted as Cu/Cu foam). Its electrocatalytic activity toward hydrazine electrooxidation is tested by linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Compared with Cu foam, hydrazine electrooxidation on the Cu/Cu foam electrode shows that the onset oxidation potential displays a ~100 mV negative shift, the current density at −0.6 V raises about 14 times, the apparent activation energy and the charge transfer resistance reduce significantly. The increasing electrocatalytic performance for hydrazine electrooxidation is mainly caused by the highly porous structure of the Cu/Cu foam electrode which can provide a large surface area and make electrolyte access the electrocatalyst surfaces more easily. Hydrazine electrooxidation on the Cu/Cu foam electrode proceeds through a near 4-electron process.
Morphology and chemical composition of Cu/Sn/Cu and Cu(5 at-%Ni)/Sn/Cu(5 at-%Ni) interconnections

NARCIS (Netherlands)

Wierzbicka-Miernik, A.; Wojewoda-Budka, J.; Litynska-Dobrzynska, L.; Kodentsov, A.; Zieba, P.

2012-01-01

In the present paper, scanning and transmission electron microscopies as well as energy dispersive X-ray spectroscopy investigations were performed to describe the morphology and chemical composition of the intermetallic phases growing in Cu/Sn/Cu and Cu(Ni)/Sn/Cu(Ni) interconnections during the
Electrodeposition of Cu-In alloys for preparing CuInS sub 2 thin films

Energy Technology Data Exchange (ETDEWEB)

Herrero, J; Ortega, J [Inst. de Energias Renovables (CIEMAT), Madrid (Spain)

1990-01-01

Copper-indium alloys were prepared by electroplating from citric acid (C{sub 6}H{sub 8}O{sub 7}.H{sub 2}O) baths onto Ti substrate. Formation of the alloys was carried out by direct codeposition of the elements and by sequential electrodeposition of copper and indium. Studies of the alloy formation by electrochemical measurements and X-ray diffraction were performed. The presence of Cu{sub 7}In{sub 4} in direct deposit as well as in sequentially electrodeposited material was observed during the alloy formation. The as-deposited layers were heated in H{sub 2}S. X-ray diffraction showed the annealed layers to be CuInS{sub 2} with the chalcopyrite structure, where the CuIn{sub 5}S{sub 8} phase was included during the annealing process. Photoelectrochemical characterization of the samples allowed us to determine the photoconductivity which is related with the Cu/In ratio in the samples. The energy gap for CuInS{sub 2} photoelectrodes in polysulphide solution was 1.57 Ev. (orig.).
Texturization of diamond-wire-sawn multicrystalline silicon wafer using Cu, Ag, or Ag/Cu as a metal catalyst

Science.gov (United States)

Wang, Shing-Dar; Chen, Ting-Wei

2018-06-01

In this work, Cu, Ag, or Ag/Cu was used as a metal catalyst to study the surface texturization of diamond-wire-sawn (DWS) multi-crystalline silicon (mc-Si) wafer by a metal-assisted chemical etching (MACE) method. The DWS wafer was first etched by standard HF-HNO3 acidic etching, and it was labeled as AE-DWS wafer. The effects of ratios of Cu(NO3)2:HF, AgNO3:HF, and AgNO3:Cu(NO3)2 on the morphology of AE-DWS wafer were investigated. After the process of MACE, the wafer was treated with a NaF/H2O2 solution. In this process, H2O2 etched the nanostructure, and NaF removed the oxidation layer. The Si {1 1 1} plane was revealed by etching the wafer in a mixture of 0.03 M Cu(NO3)2 and 1 M HF at 55 °C for 2.5 min. These parallel Si {1 1 1} planes replaced some parallel saw marks on the surface of AE-DWS wafers without forming a positive pyramid or an inverted pyramid structure. The main topography of the wafer is comprised of silicon nanowires grown in direction when Ag or Ag/Cu was used as a metal catalyst. When silicon is etched in a mixed solution of Cu(NO3)2, AgNO3, HF and H2O2 at 55 °C with a concentration ratio of [Cu2+]/[Ag+] of 50 or at 65 °C with a concentration ratio of [Cu2+]/[Ag+] of 33, a quasi-inverted pyramid structure can be obtained. The reflectivity of the AE-DWS wafers treated with MACE is lower than that of the multiwire-slurry-sawn (MWSS) mc-Si wafers treated with traditional HF + HNO3 etching.
Detailed Visualization of Phase Evolution during Rapid Formation of Cu(InGa)Se2 Photovoltaic Absorber from Mo/CuGa/In/Se Precursors.

Science.gov (United States)

Koo, Jaseok; Kim, Sammi; Cheon, Taehoon; Kim, Soo-Hyun; Kim, Woo Kyoung

2018-03-02

Amongst several processes which have been developed for the production of reliable chalcopyrite Cu(InGa)Se 2 photovoltaic absorbers, the 2-step metallization-selenization process is widely accepted as being suitable for industrial-scale application. Here we visualize the detailed thermal behavior and reaction pathways of constituent elements during commercially attractive rapid thermal processing of glass/Mo/CuGa/In/Se precursors on the basis of the results of systematic characterization of samples obtained from a series of quenching experiments with set-temperatures between 25 and 550 °C. It was confirmed that the Se layer crystallized and then melted between 250 and 350 °C, completely disappearing at 500 °C. The formation of CuInSe 2 and Cu(InGa)Se 2 was initiated at around 450 °C and 550 °C, respectively. It is suggested that pre-heat treatment to control crystallization of Se layer should be designed at 250-350 °C and Cu(InGa)Se 2 formation from CuGa/In/Se precursors can be completed within a timeframe of 6 min.
Interdiffusion within model TiN/Cu and TiTaN/Cu systems synthesized by combinatorial thin film deposition

International Nuclear Information System (INIS)

Mühlbacher, M.

2015-01-01

Continued device miniaturization in microelectronics calls for a fundamental understanding of diffusion processes and damage mechanisms in the Cu metallization/TiN barrier layer system. Thus, the starting point of the present study is a combined experimental and theoretical examination of lattice diffusion in ideal single-crystal TiN/Cu stacks grown on MgO(001) by unbalanced DC magnetron sputter deposition. After a 12 h annealing treatment at 1000 °C, a uniform Cu diffusion layer of 7-12 nm is observed by scanning transmission electron microscopy and atom probe tomography (APT). Density-functional theory calculations predict a stoichiometry-dependent atomic diffusion mechanism of Cu in bulk TiN, with Cu diffusing on the N sublattice for the experimental N/Ti ratio of 0.92. These findings are extended to a comparison of grain boundary diffusion of Cu in dense polycrystalline TiN sputter-deposited on Si at 700 °C and underdense polycrystalline TiN grown on Si without external substrate heating. While the Cu diffusion path along dense TiN grain boundaries can be restricted to approximately 30 nm after a 1 h annealing treatment at 900 °C as visualized by 3D APT reconstructions, it already exceeds 500 nm after annealing at 700 °C in the underdense low-temperature TiN barrier. In this case, the formation of the Cu3Si phase, which characteristically grows along the close-packed directions in Si, is identified as the main damage mechanism leading to complete barrier failure. To meet the low-temperature processing needs of semiconductor industry and at the same time exploit the improved performance of dense polycrystalline barrier layers, deposition of TiTaN barriers on Si is demonstrated by a reactive hybrid high-power impulse/DC magnetron sputtering process, where barrier densification is achieved by pulsed irradiation of the growth surface with only a few at.% of energetic Ta ions without external substrate heating. These barrier layers delay the onset of Cu grain
Solid state reactions and diffusion processes during rapid thermal processing of Cu-In-S based semiconductors; Festkoerperreaktionen und Diffusionsprozesse bei der schnellen Bildung von Halbleiterschichten im System Cu-In-S

Energy Technology Data Exchange (ETDEWEB)

Enzenhofer, T

2007-12-14

In this thesis thin layers of the system Cu-In-S were studied for the photovoltaic application by means of structural and electro-optical procedures. The effect of small quantities of group II elements on the absorber and component properties could be explained by a widely appointed study. The motivation to insert extraneous elements into CuInS{sub 2} absorber layers results from the too low zero-current voltage of CuInS{sub 2} based solar cells. It could be shown that by addition of small quantities of Zn and/or Mg (<1 at.%) the zero-current voltage can be increased by 90 mV. The best doped CuInS{sub 2} solar cells aimed efficiencies, which were also determined for the reference system. As limiting factor in the doped system the zero-current has been proved. The intensive analysis of the absorber properties showed the the extraneous atoms effect in the bulk and on the surface different modifications.
Fabrication and characterization of Bi2Sr2CaCu2O8+δ stacks by self-planarizing process

International Nuclear Information System (INIS)

Okanoue, K.; Ishida, H.; Funabiki, H.; Hamasaki, K.; Shimakage, N.; Kawakami, A.; Wang, Z.; Abe, H.

2005-01-01

We developed a new fabrication process of stacked intrinsic Josephson junctions using superconducting Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212) single crystals. In the proposed self-planarizing process, the Bi-2212 crystal around the junction window was modified to insulator by soaking into the solution of dilute (0.05-0.2%) hydrochloric acid for 5 s. Energy dispersive X-ray (EDX) spectroscopy revealed that the acid-treated Bi-2212 exhibited the decrease of Cu and Sr contents in the crystals. The current-voltage characteristic of the stacks showed distinct resistive branches with large hysteresis at 77 K. The number of intrinsic junctions in the stacks linearly decreased with decreasing the concentration of the solution. The well controllability of the number of junctions in the self-planarized stacks may be useful for electronic device applications
Melt-processed Gd-Ba-Cu-O superconductor with trapped field of 3 T at 77 K

International Nuclear Information System (INIS)

Nariki, S; Sakai, N; Murakami, M

2005-01-01

We fabricated a single-domain Gd-Ba-Cu-O bulk superconductor 65 mm in diameter and studied the microstructure, superconducting and field-trapping properties. Melt-processing was performed under a controlled oxygen partial pressure of 1.0% using a precursor containing Gd123 and Gd211 powders in a molar ratio of 2:1, with 0.5 wt% of Pt and 20 wt% of Ag 2 O added. The distribution of Ag and Gd211 particles was almost homogeneous. The addition of Ag was very effective in reducing the amount of cracking in the sample. The maximum trapped magnetic field recorded was 3.05 T at 77 K. We also measured the trapped field between two Gd-Ba-Cu-O bulk samples in order to minimize the demagnetizing effect and found that the trapped field reached 4.3 T at 77 K
IR and TPD studies of the interaction of alkenes with Cu + sites in CuNaY and CuNaX zeolites of various Cu content. The heterogeneity of Cu + sites

Science.gov (United States)

Datka, J.; Kukulska-Zajaç, E.; Kozyra, P.

2006-08-01

Cu + ions in zeolites activate organic molecules containing π electrons by π back donation, which results in a distinct weakening of multiple bonds. In this study, we followed the activation of alkenes (ethene and propene) by Cu + ions in CuY and CuX zeolites of various Cu content. We also studied the strength of bonding of alkenes to Cu + ions. IR studies have shown that there are two kinds of Cu + sites of various electron donor properties. We suppose that they could be attributed to the presence of Cu + ions of various number of oxygen atoms surrounding the cation. IR studies have shown that Cu ions introduced into Y and X zeolites in the first-order (at low Cu content) form Cu + ions of stronger electron donor properties (i.e. activate alkenes to larger extend) than Cu ions introduced in the next order (at higher Cu content). IR and TPD studies of alkenes desorption evidenced that Cu + ions of stronger electron donor properties bond alkenes stronger than less electron donor ones. It suggests that π back donation has more important contribution to the strength of bonding alkenes to cation than π donation.
Simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by electro-Fenton process using iron sacrificing electrodes.

Science.gov (United States)

Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Tang, Junyi; Wu, Yang

2018-05-15

This research explored the application of electro-Fenton (E-Fenton) technique for the simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by using iron sacrificing electrodes. Standard discharge (0.3 mg L -1 for Cu and 0.1 mg L -1 for Ni in China) could be achieved after 30 min reaction under the optimum conditions (i.e. initial solution pH of 2.0, H 2 O 2 dosage of 6 mL L -1  h -1 , current density of 20 mA/cm 2 , inter-electrode distance of 2 cm, and sulfate electrolyte concentration of 2000 mg L -1 ). The distinct differences in apparent kinetic rate constants (k app ) and intermediate removal efficiencies corresponding to mere and blended systems indicated the mutual promotion effect toward the decomplexation between Cu(II) and Ni(II). Massive accumulation of Fe(Ⅲ) favored the further removal of Cu(II) and Ni(II) by metal ion substitution. Species distribution results demonstrated that the decomplexation of metal-EDTA in E-Fenton process was mainly contributed to the combination of various reactions, including Fenton reaction together with the anodic oxidation, electro-coagulation (E-coagulation) and electrodeposition. Unlike hypophosphite and citrate, the presence of chlorine ion displayed favorable effects on the removal efficiencies of Cu(II) and Ni(II) at low dosage, but facilitated the ammonia nitrogen (NH 4 + -N) removal only at high dosage. Copyright © 2018 Elsevier B.V. All rights reserved.
The Use of Al, Cu, and Fe in an Integrated Electrocoagulation-Ozonation Process

Directory of Open Access Journals (Sweden)

Carlos E. Barrera Díaz

2015-01-01

Full Text Available This study presents the effect of supplying electrochemically generated metallic ions (Al, Cu, and Fe during an ozonation process for treating industrial wastewater. The pollutant removal efficiencies of the electrocoagulation (EC, ozonation, and coupled EC-ozonation processes were examined by the decrease in chemical oxygen demand (COD as a function of treatment time. The EC was performed in a raw industrial wastewater, which has contributions from 39 chemical, 34 metal finishing, 22 textile, 11 leather, and 5 automotive plants, at pH (7.3 using a current density of 150 A/m2 for 60 min, giving a 45% reduction in COD. The ozonation process was more effective with the same wastewater, reducing the COD by 52% after 60 min of treatment. Combining the EC and ozonation methods resulted in a synergistic process that improves the reduction of COD in a shorter time. In just 12 min the integrated process reduced the COD by 88%. Thus, the combination of EC and ozonation processes improves noticeably the wastewater quality, decreasing the treatment time and also reducing the sludge production.
Solution-processed inorganic copper(I) thiocyanate (CuSCN) hole transporting layers for efficient p–i–n perovskite solar cells

KAUST Repository

Zhao, Kui; Munir, Rahim; Yan, Buyi; Yang, Yang; Kim, Taesoo; Amassian, Aram

2015-01-01

CuSCN is a highly transparent, highly stable, low cost and easy to solution process HTL that is proposed as a low cost replacement to existing organic and inorganic metal oxide hole transporting materials. Here, we demonstrate hybrid organic
Fabrication of Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} solar cells by ethanol-ammonium solution process

Energy Technology Data Exchange (ETDEWEB)

Xue, Cong; Li, Jianmin; Wang, Yaguang; Jiang, Guoshun; Weifeng, Liu, E-mail: liuwf@ustc.edu.cn; Zhu, Changfei, E-mail: cfzhu@ustc.edu.cn

2016-10-15

Highlights: • The CBD precipitates were utilized to fabricate the CZTS/CZTSSe solar cells. • A solvent mixture of ethanol and ammonium hydroxide was used to form SnS-Cu2O-ZnS slurry. • Formation of CZTS/CZTSSe with good crystalline quality confirmed by XRD and Raman spectra. • CZTS and CZTSSe thin film solar cells obtained the best PCE of 1.99% and 2.95%, respectively. - Abstract: In this paper, Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} precursor films were produced by doctor blade process from SnS-Cu{sub 2}O-ZnS slurry. To prepare the slurry, SnS, ZnS and Cu{sub 2}O precipitates, which are outgrowths of stacked layer ZnS/Cu/SnS by CBD (chemical bath deposition)-annealing route, were dissolved in the mixture solvent of ethanol and NH{sub 3}·H{sub 2}O. Synthesized precursor films were then annealed at different conditions. The post-annealed films were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman measurements and UV–vis–NIR spectroscopy. SEM studies reveal that the rough and relatively compact absorber thin films are obtained via the sulfidation and sulfidation-selenization processes. X-ray diffraction and Raman spectrum results verify that the obtained films are composed of Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} phases, which have high absorbance in visible range and direct band gap energy of 1.01–1.47 eV. The best devices yield total area power conversion efficiency of 1.99% and 2.95% corresponding to Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} thin film solar cells under AM1.5 illumination without any anti-reflection layer.
Preparation of PtSnCu/C and PtSn/C electrocatalysts and activation by dealloying processes for ethanol electrooxidation; Preparacao de eletrocatalisadores PtSnCu/C e PtSn/C e ativacao por processos de dealloying para aplicacao na oxidacao eletroquuimica do etanol

Energy Technology Data Exchange (ETDEWEB)

Crisafulli, Rudy

2013-06-01

PtSnCu/C (with different Pt:Sn:Cu atomic ratios) and PtSn/C (50:50) electrocatalysts were prepared by borohydride (BR) and alcohol-reduction (AR) processes using H{sub 2}PtCl{sub 6}.6H{sub 2}O, SnCl{sub 2}.2H{sub 2}O and CuCl{sub 2}.2H{sub 2}O as metal sources, NaBH{sub 4} and ethylene glycol as reducing agents, 2-propanol and ethylene glycol/water as solvents and carbon black as support. In a further step, these electrocatalysts were activated by chemical (CD) and electrochemical (ED) dealloying processes through acid treatment and thin porous coating technique, respectively. These materials were characterized by energy dispersive X-ray, Xray diffraction, transmission electron microscopy, line scan energy dispersive Xray and cyclic voltammetry. Electrochemical studies for ethanol electro-oxidation were performed by cyclic voltammetry, chronoamperometry and in single Direct Ethanol Fuel Cell using Membrane Electrode Assembly (MEA). The anodic effluents were analysed by gas chromatography. The X-ray diffractograms of the as-synthesized electrocatalysts showed the typical face-centered cubic structure (FCC) of platinum and its alloys. After dealloying, the X-ray diffractograms showed that the Pt FCC structure was preserved. The crystallite sizes of the assynthesized electrocatalysts were in the range of <=2 nm to 3 nm and after dealloying there were no significant variations in sizes. The energy dispersive Xray analysis of the as-synthesized electrocatalysts showed a Pt:Sn and Pt:Sn:Cu atomic ratios similar to the nominal values. After chemical and electrochemical dealloying of the electrocatalysts the ranged Pt:Sn and Pt:Sn:Cu atomic ratios showed that Cu and Sn atoms were removed. However, chemical dealloying process proved to be more efficient for removing Cu and electrochemical dealloying for removing Sn. The line scan energy dispersive X-ray analysis showed that acid and electrochemical treatments were efficient to dealloying Cu and/or Sn superficial atoms of
Optical constants of Cu(In, Ga)Se{sub 2} for arbitrary Cu and Ga compositions

Energy Technology Data Exchange (ETDEWEB)

Minoura, Shota; Kodera, Keita; Nakane, Akihiro; Fujiwara, Hiroyuki, E-mail: fujiwara@gifu-u.ac.jp [Center of Innovative Photovoltaic Systems (CIPS), Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Maekawa, Takuji [Research and Development Headquarters, ROHM Co., Ltd., 21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585 (Japan); Niki, Shigeru [Research Center for Photovoltaic Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Central2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

2015-05-21

The optical constants of Cu(In, Ga)Se{sub 2} (CIGS)-based polycrystalline layers with different Cu and Ga compositions are parameterized completely up to a photon energy of 6.5 eV assuming several Tauc-Lorentz transition peaks. Based on the modeled optical constants, we establish the calculation procedure for the CIGS optical constants in a two-dimensional compositional space of (Cu, Ga) by taking the composition-induced shift of the critical point energies into account. In particular, we find that the variation of the CIGS optical constants with the Cu composition can be modeled quite simply by a spectral-averaging method in which the dielectric function of the target Cu composition is estimated as a weighted average of the dielectric functions with higher and lower Cu compositions. To express the effect of the Ga composition, on the other hand, an energy shift model reported earlier is adopted. Our model is appropriate for a wide variety of CIGS-based materials having different Cu and Ga compositions, although the modeling error increases slightly at lower Cu compositions [Cu/(In + Ga) < 0.69]. From our model, the dielectric function, refractive index, extinction coefficient, and absorption coefficient for the arbitrary CIGS composition can readily be obtained. The optical database developed in this study is applied further for spectroscopic ellipsometry analyses of CIGS layers fabricated by single and multi-stage coevaporation processes. We demonstrate that the compositional and structural characterizations of the CIGS-based layers can be performed from established analysis methods.
Friction and wear characteristics of Al-Cu/C composites synthesized using partial liquid phase casting process

International Nuclear Information System (INIS)

Ng, W.B.; Gupta, M.; Lim, S.C.

1997-01-01

During the sliding of aluminium alloys dispersed with graphite particulates, a layer of graphite is usually present at the sliding interface. This tribo-layer significantly reduces the amount of direct metal-to-metal contact, giving rise to low friction and a low rate of wear, making these composites useful candidate materials for anti-friction applications. Such self-lubricating composites are commonly fabricated via the squeeze casting, slurry casting or powder metallurgy route. These processes are expensive while the less-expensive conventional casting route is limited by the agglomeration of graphite particles in the composites, giving rise to poor mechanical properties. In this work, graphite particulate-reinforced Al-4.5 wt.% Cu composites with two effective graphite contents (Al-4.5 Cu/4.2 wt.% C and Al-4.5 Cu/6.8 wt.% C) were synthesized through an innovative partial liquid phase casting (rheocasting) technique, which is a modification of the conventional casting process. Unlubricated (without the use of conventional liquid lubrication) friction and wear performance of these composites as well as the un-reinforced aluminium alloy was determined using a pin-on-disk tester. The results revealed that the graphite-reinforced composites have a higher wear rate than the un-reinforced matrix alloy while their frictional characteristics are very similar within the range of testing conditions. Combining these with the information gathered from worn-surface examinations and wear-debris analysis, it is suggested that there exists a certain threshold for the amount and size of graphite particulates in these composites to enable them to have improved tribological properties. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)
Porous HKUST-1 derived CuO/Cu2O shell wrapped Cu(OH)2 derived CuO/Cu2O core nanowire arrays for electrochemical nonenzymatic glucose sensors with ultrahigh sensitivity

Science.gov (United States)

Yu, Cuiping; Cui, Jiewu; Wang, Yan; Zheng, Hongmei; Zhang, Jianfang; Shu, Xia; Liu, Jiaqin; Zhang, Yong; Wu, Yucheng

2018-05-01

Self-supported CuO/Cu2O@CuO/Cu2O core-shell nanowire arrays (NWAs) are successfully fabricated by a simple and efficient method in this paper. Anodized Cu(OH)2 NWAs could in-situ convert to HKUST-1 at room temperature easily. Cu(OH)2 NWAs cores and HKUST-1 shells transform into CuO/Cu2O simultaneously after calcinations and form CuO/Cu2O@CuO/Cu2O core-shell NWAs. This smart configuration of the core-shell structure not only avoids the agglomeration of the traditional MOF-derived materials in particle-shape, but also facilitates the ion diffusion and increases the active sites. This novel structure is employed as substrate to construct nonenzymatic glucose sensors. The results indicate that glucose sensor based on CuO/Cu2O@CuO/Cu2O core-shell NWAs presents ultrahigh sensitivity (10,090 μA mM-1 cm-2), low detection limit (0.48 μM) and wide linear range (0.99-1,330 μM). In addition, it also shows excellent anti-interference ability toward uric acid, ascorbic acid and L-Cysteine co-existing with glucose, good reproducibility and superior ability of real sample analysis.
Containerless processing of YBa2Cu3O7-δ superconductors

International Nuclear Information System (INIS)

Olive, J.R.; Hofmeister, W.H.; Bayuzick, R.J.; Carro, G.; McHugh, J.P.; Hopkins, R.H.; Vlasse, M.

1993-01-01

Containerless processing of YBa 2 Cu 3 O 7-δ was performed using drop tube and aero-acoustic levitation techniques. In drop tube experiments, two solidification microstructures developed which corresponded to the degree of melting. In aero-acoustic levitation experiments, three solidification microstructures developed. One microstructure was the result of incomplete homogenization of the melt. The second was due to slight undercooling into the Y 2 O 3 + liquid region of the phase diagram upon which primary Y 2 O 3 dendrites formed. The third was due to much deeper undercooling. In this case, the primary solidification structure consisted of dendrites of tetragonal 1:2:3 and some other interdendritic phase. Subsequent to solidification processing, these samples were annealed to single phase 1:2:3 with orthorhombic symmetry. SQUID magnetometer measurements indicated a sharp superconducting transition at approximately 85 K. Magnetic J c values, calculated using the Bean critical state model, indicated that the deeply undercooled and annealed samples had critical current densities on the order of 10 4 Acm -2

Production of diamond wire by Cu15 v-% Nb 'in situ' process

International Nuclear Information System (INIS)

Filgueira, M.; Pinatti, D.G.

2001-01-01

Diamond wires are cutting tools used in the slabbing of dimension stones, such as marbles and granites, as well as in cutting of concrete structures. This tool consists of a steel cable on which diamond annular segments (pearls) are mounted with spacing between them. This work has developed a new technological route to obtain the diamond wires, whose fabrication involves metal forming processes such as rotary forging and wire drawing, copper tubes restacking, and thermal treatments of sintering and recrystallization. It was idealized the use of Cu 15v% Nb composite wires as the high tensile strength cable, covered with an external cutting rope made of bronze 4wt% diamond composite, along the overall wire surface. Investigations were carried out on the mechanical behavior and on the microstructural evolution of the Cu 15 vol % Nb wires, which showed ultimate tensile strength (UTS) of 960 MPa and deformation of approximately 3,0 %. The cutting external rope of 1.84 mm in diameter showed UTS = 230 MPa. On the microstructural side aspect it was observed that the diamond crystals were uniformly distributed throughout the tool bulk in the several processing steps. Cutting tests were carried out starting with an external diamond rope of 1.93 mm in diameter, which cut a marble sectional area of 1188 cm 2 , and the tool degraded to a final diameter of 1.23 mm. For marble the 'in situ' wire showed a probable performance 4 times higher than the diamond saws, however their probable performance was about 5 to 8 times less than the conventional diamond wires due to the low abrasion resistance of the bronze matrix and the low adhesion between the pair bronze-diamond. (author)
Comparative study of Cu-Zr and Cu-Ru alloy films for barrier-free Cu metallization

International Nuclear Information System (INIS)

Wang Ying; Cao Fei; Zhang Milin; Liu Yuntao

2011-01-01

The properties of Cu-Zr and Cu-Ru alloy films were comparatively studied to evaluate their potential use as alloying elements. Cu alloy films were deposited on SiO 2 /Si substrates by magnetron sputtering. Samples were subsequently annealed and analyzed by four-point probe measurement, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Auger electron spectroscopy. X-ray diffraction data suggest that Cu film has preferential (111) crystal orientation and no extra peak corresponding to any compound of Cu, Zr, Ru, and Si. According to transmission electron microscopy results, Cu grains grow in size for both systems but the grain sizes of the Cu alloy films are smaller than that of pure Cu films. These results indicate that Cu-Zr film is suitable for advanced barrier-free metallization in terms of interfacial stability and lower resistivity.
Antimicrobial Cu-bearing stainless steel scaffolds

Energy Technology Data Exchange (ETDEWEB)

Wang, Qiang, E-mail: mfqwang@163.com [School of Stomatology, China Medical University, Shenyang 110002 (China); Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences (China); Li, Xiaopeng [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Zhang, Shuyuan [Institute of Metal Research, Chinese Academy of Sciences (China); Sercombe, Timothy B., E-mail: tim.sercombe@uwa.edu.au [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences (China)

2016-11-01

Copper-bearing stainless steel scaffolds with two different structures (Body Centered Cubic and Gyroid labyrinth) at two solid fractions (25% and 40%) were fabricated from both 316L powder and a mixture of 316L and elemental Cu powder using selective laser melting, and relative 316L scaffolds were served as control group. After processing, the antimicrobial testing demonstrated that the 316L-Cu scaffolds presented excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, and the cell viability assay indicated that there was no cytotoxic effect of 316L-Cu scaffolds on rat marrow mesenchymal stem cells. As such, these have the potential to reduce implant-associated infections. The Cu was also found to homogeneously distribute within the microstructure by scanning electronic microcopy. The addition of Cu would not significantly affect its strength and stiffness compared to 316L scaffold, and the stiffness of all the scaffolds (3-20GPa) is similar to that of bone and much less than that of bulk stainless steel. Consequently, fabrication of such low stiffness porous structures, especially coupled with the addition of antimicrobial Cu, may provide a new direction for medical stainless steels. - Highlights: • 316L-Cu scaffolds were fabricated by using selective laser melting (SLM). • 316L-Cu scaffolds showed satisfied antimicrobial activities. • 316L-Cu scaffolds have no cytotoxic effect on normal cells. • Other properties of 316L-Cu scaffolds were similar to 316L scaffolds. • 316L-Cu scaffolds have the potential to be used in orthopedic applications.
Antimicrobial Cu-bearing stainless steel scaffolds

International Nuclear Information System (INIS)

Wang, Qiang; Ren, Ling; Li, Xiaopeng; Zhang, Shuyuan; Sercombe, Timothy B.; Yang, Ke

2016-01-01

Copper-bearing stainless steel scaffolds with two different structures (Body Centered Cubic and Gyroid labyrinth) at two solid fractions (25% and 40%) were fabricated from both 316L powder and a mixture of 316L and elemental Cu powder using selective laser melting, and relative 316L scaffolds were served as control group. After processing, the antimicrobial testing demonstrated that the 316L-Cu scaffolds presented excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, and the cell viability assay indicated that there was no cytotoxic effect of 316L-Cu scaffolds on rat marrow mesenchymal stem cells. As such, these have the potential to reduce implant-associated infections. The Cu was also found to homogeneously distribute within the microstructure by scanning electronic microcopy. The addition of Cu would not significantly affect its strength and stiffness compared to 316L scaffold, and the stiffness of all the scaffolds (3-20GPa) is similar to that of bone and much less than that of bulk stainless steel. Consequently, fabrication of such low stiffness porous structures, especially coupled with the addition of antimicrobial Cu, may provide a new direction for medical stainless steels. - Highlights: • 316L-Cu scaffolds were fabricated by using selective laser melting (SLM). • 316L-Cu scaffolds showed satisfied antimicrobial activities. • 316L-Cu scaffolds have no cytotoxic effect on normal cells. • Other properties of 316L-Cu scaffolds were similar to 316L scaffolds. • 316L-Cu scaffolds have the potential to be used in orthopedic applications.
Soldering-induced Cu diffusion and intermetallic compound formation between Ni/Cu under bump metallization and SnPb flip-chip solder bumps

Science.gov (United States)

Huang, Chien-Sheng; Jang, Guh-Yaw; Duh, Jenq-Gong

2004-04-01

Nickel-based under bump metallization (UBM) has been widely used as a diffusion barrier to prevent the rapid reaction between the Cu conductor and Sn-based solders. In this study, joints with and without solder after heat treatments were employed to evaluate the diffusion behavior of Cu in the 63Sn-37Pb/Ni/Cu/Ti/Si3N4/Si multilayer structure. The atomic flux of Cu diffused through Ni was evaluated from the concentration profiles of Cu in solder joints. During reflow, the atomic flux of Cu was on the order of 1015-1016 atoms/cm2s. However, in the assembly without solder, no Cu was detected on the surface of Ni even after ten cycles of reflow. The diffusion behavior of Cu during heat treatments was studied, and the soldering-process-induced Cu diffusion through Ni metallization was characterized. In addition, the effect of Cu content in the solder near the solder/intermetallic compound (IMC) interface on interfacial reactions between the solder and the Ni/Cu UBM was also discussed. It is evident that the (Cu,Ni)6Sn5 IMC might form as the concentration of Cu in the Sn-Cu-Ni alloy exceeds 0.6 wt.%.
Small changes in Cu redox state and speciation generate large isotope fractionation during adsorption and incorporation of Cu by a phototrophic biofilm

Science.gov (United States)

Coutaud, Margot; Méheut, Merlin; Glatzel, Pieter; Pokrovski, Gleb S.; Viers, Jérôme; Rols, Jean-Luc; Pokrovsky, Oleg S.

2018-01-01

Despite the importance of phototrophic biofilms in metal cycling in freshwater systems, metal isotope fractionation linked to metal adsorption and uptake by biofilm remains very poorly constrained. Here, copper isotope fractionation by a mature phototrophic biofilm during Cu surface adsorption and incorporation was studied in batch reactor (BR) and open drip flow reactor (DFR) systems at ambient conditions. X-ray Absorption Spectroscopy (both Near Edge Structure, XANES, and Extended Fine Structure, EXAFS) at Cu K-edge of the biofilm after its interaction with Cu in BR experiments allowed characterizing the molecular structure of assimilated Cu and quantifying the degree of CuII to CuI reduction linked to Cu assimilation. For both BR and DFR experiments, Cu adsorption caused enrichment in heavy isotope at the surface of the biofilm relative to the aqueous solution, with an apparent enrichment factor for the adsorption process, ε65Cuads, of +1.1 ± 0.3‰. In contrast, the isotope enrichment factor during copper incorporation into the biofilm (ε65Cuinc) was highly variable, ranging from -0.6 to +0.8‰. This variability of the ε65Cuinc value was likely controlled by Cu cellular uptake via different transport pathways resulting in contrasting fractionation. Specifically, the CuII storage induced enrichment in heavy isotope, whereas the toxicity response of the biofilm to Cu exposure resulted in reduction of CuII to CuI, thus yielding the biofilm enrichment in light isotope. EXAFS analyses suggested that a major part of the Cu assimilated by the biofilm is bound to 5.1 ± 0.3 oxygen or nitrogen atoms, with a small proportion of Cu linked to sulfur atoms (NS biofilm exhibited a similar trend over time of exposure. Our study demonstrates the complexity of biological processes associated with live phototrophic biofilms, which produce large and contrasting isotope fractionations following rather small Cu redox and speciation changes during uptake, storage or release of
Effect of Process Parameters on Fatigue and Fracture Behavior of Al-Cu-Mg Alloy after Creep Aging

Directory of Open Access Journals (Sweden)

Lihua Zhan

2018-04-01

Full Text Available A set of creep aging tests at different aging temperatures and stress levels were carried out for Al-Cu-Mg alloy, and the effects of creep aging on strength and fatigue fracture behavior were studied through tensile tests and fatigue crack propagation tests. The microstructures were further analyzed by using scanning electron microscopy (SEM and transmission electron microscopy (TEM. The results show that temperature and stress can obviously affect the creep behavior, mechanical properties, and fatigue life of Al-Cu-Mg alloy. As the aging temperature increases, the fatigue life of alloy first increases, and then decreases. The microstructure also displays a transition from the Guinier-Preston-Bagaryatsky (GPB zones to the precipitation of S phase in the grain interior. However, the precipitation phases grow up and become coarse at excessive temperatures. Increasing stress can narrow the precipitation-free zone (PFZ at the grain boundary and improve the fatigue life, but overhigh stress can produce the opposite result. In summary, the fatigue life of Al-Cu-Mg alloy can be improved by fine-dispersive precipitation phases and a narrow PFZ in a suitable creep aging process.
Formation of nanoparticles and defects in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} prepared by the metal organic deposition process

Energy Technology Data Exchange (ETDEWEB)

Goswami, R. [Naval Research Laboratory, Washington, DC 20375 (United States); SAIC, Washington, DC 20003 (United States)], E-mail: goswami@anvil.nrl.navy.mil; Holtz, R.L. [Naval Research Laboratory, Washington, DC 20375 (United States); Rupich, M.W. [American Superconductors Inc., Westborough, MA 01581 (United States); Spanos, G. [Naval Research Laboratory, Washington, DC 20375 (United States)

2007-11-15

Nanoparticles and defects have been investigated using transmission electron microscopy in fully reacted YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO), prepared by the metal-organic deposition (MOD) process. Two types of particles, Y{sub 2}O{sub 3} and CuY{sub 2}O{sub 5}, ranging from 10 to 100 nm, have been observed in the YBCO matrix. The YBCO contains a large number of planar defects and a considerable number of (1 1 0) rotational twins. Details of the nanoparticles and defects in the MOD-processed YBCO films are presented in this paper.
Synthesis of CuInSe2 thin films from electrodeposited Cu11In9 precursors by two-step annealing

Directory of Open Access Journals (Sweden)

TSUNG-WEI CHANG

2014-02-01

Full Text Available In this study, copper indium selenide (CIS films were synthesized from electrodeposited Cu-In-Se precursors by two-step annealing. The agglomeration phenomenon of the electrodeposited In layer usually occurred on the Cu surface. A thermal process was adopted to turn Cu-In precursors into uniform Cu11In9 binary compounds. After deposition of the Se layer, annealing was employed to form chalcopyrite CIS. However, synthesis of CIS from Cu11In9 requires sufficient thermal energy. Annealing temperature and time were investigated to grow high quality CIS film. Various electrodeposition conditions were investigated to achieve the proper atomic ratio of CIS. The properties of the CIS films were characterized by scanning electron microscopy (SEM, X-ray Diffraction (XRD, and Raman spectra.
Corrosion behavior of Cu during graphene growth by CVD

International Nuclear Information System (INIS)

Dong, Yuhua; Liu, Qingqing; Zhou, Qiong

2014-01-01

Highlights: • Graphene films were deposited on the Cu by chemical vapor deposition method. • Annealing affects the corrosion property of Cu. • Graphene films improve corrosion performance of Cu for a short period of time. - Abstract: The corrosion performance of Cu samples may be affected by annealing at high temperatures during graphene growth via the chemical vapor deposition method. In this study, multiple graphene films were deposited on Cu and characterized by Raman spectroscopy and transmission electron microscopy. The corrosion behavior of Cu immersed in 3.5 wt.% NaCl solution was investigated using electrochemical impedance spectroscopy. The Cu morphology was observed by optical microscopy and scanning electron microscopy. Results indicated that annealing affects the corrosion process of Cu. The presence of graphene films on the Cu substrate improved the corrosion performance of the material for a short period of time
Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

International Nuclear Information System (INIS)

Xiao, H.; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

2013-01-01

Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R 0 /R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints
Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

Energy Technology Data Exchange (ETDEWEB)

Xiao, H., E-mail: xiaohui2013@yahoo.com.cn; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

2013-11-25

Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R{sub 0}/R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints.
Melt processing of Bi-Ca-Sr-Cu-O superconductors

International Nuclear Information System (INIS)

Zanotto, E.D.; Cronin, J.P.; Dutta, B.

1988-01-01

Several Bi-Ca-Sr-Cu-O compositions were melted in Al/sub 2/O/sub 3/ or Pt crucibles at temperatures between 1050C and 1200C. As-quenched specimens crystallized from the upper surfaces, while the bottom layers were glassy. Glass formation was improved for higher Bi/sub 2/O/sub 3/ concentrations. The crystalline portions were highly conductive, while the glassy layers were insulating. Both did not show superconductivity down to 10K. Thermal treatment in air caused a dramatic effect on the electronic properties; and annealing at 865C for long periods converted the two types of specimens (previously glassy or crystalline) to superconductors, at least for one composition. Aluminum impurity (up to 8.6 atom. pct.) had no detectable effect on the transition temperatures, i.e., T/sub c/ 85K for all superconducting samples. The flake-like (Bi/sub 2/Ca/sub 1/Sr/sub 2/Cu/sub 2/) phase, reported by other authors, was responsible for superconductivity
CuGeO3 and CuO by respectively elastic and inelastic polarized neutrons

International Nuclear Information System (INIS)

Ain, M.; Regnault, L.P.; Lorenzo, J.; Dhalenne, G.; Revcolevschi, A.

2005-01-01

Polarization analysis permitted to verify very promptly that the plane of the helix in the incommensurate phase of CuO was not (a*,c*) as first proposed but another one containing without equivoque the b*-axis.Inelastic polarization analysis under applied magnetic field permitted to study the triplet magnon-like mode of spin-Peierls CuGeO 3 . This mode splits in three, as expected. Intensities of inelastic neutron scattering measurements with polarization analysis have been collected in both spin-flip and nonspin-flip channels. This Zeeman splitting revealed that two out of the three processes are purely spin-flip excitations, while the third undisplaced one is a nonspin-flip process in which the neutron conserves its spin orientation
Surface plasmon resonance enhanced visible-light-driven photocatalytic activity in Cu nanoparticles covered Cu{sub 2}O microspheres for degrading organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Cheng, Yahui, E-mail: chengyahui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Lin, Yuanjing [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Xu, Jianping [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); He, Jie; Wang, Tianzhao; Yu, Guojun; Shao, Dawei; Wang, Wei-Hua; Lu, Feng [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Li, Lan [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); Du, Xiwen [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang, Weichao [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Liu, Hui, E-mail: liuhui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Zheng, Rongkun [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

2016-03-15

Graphical abstract: - Highlights: • Cu NPs introduce the SPR and result in an increase of visible light absorption. • The photocatalytic activity of Cu{sub 2}O/Cu improves greatly due to the SPR effect. • A dark catalytic activity is observed stemming from the Fenton-like reaction. • The • O{sub 2}{sup −} and • OH radicals contribute to the photocatalytic process. • The • OH radicals contribute to the dark catalytic process. - Abstract: Micron-sized Cu{sub 2}O with different coverage of Cu nanoparticles (NPs) on the sphere has been synthesized by a redox procedure. The absorption spectra show that Cu NPs induce the surface plasmon resonance (SPR) at the wavelength of ∼565 nm. Methylene blue (MB) photodegrading experiments under visible-light display that the Cu{sub 2}O–Cu–H{sub 2}O{sub 2} system exhibits a superior photocatalytic activity to Cu{sub 2}O–H{sub 2}O{sub 2} or pure H{sub 2}O{sub 2} with an evident dependency on Cu coverage. The maximum photodegradation rate is 88% after visible-light irradiating for 60 min. The role of the Cu NPs is clarified through photodegradation experiments under 420 nm light irradiation, which is different from the SPR wavelength of Cu NPs (∼565 nm). By excluding the SPR effect, it proves that Cu SPR plays a key role in the photodegradation. Besides, a dark catalytic activity is observed stemming from the Fenton-like reaction with the aid of H{sub 2}O{sub 2}. The radical quenching experiments indicate that both • O{sub 2}{sup −} and • OH radicals contribute to the photocatalysis, while the dark catalysis is only governed by the • OH radicals, leading to a lower activity comparing with the photocatalysis. Therefore, with introducing Cu NPs and H{sub 2}O{sub 2}, the Cu{sub 2}O-based photocatalytic activity could be significantly improved due to the SPR effect and dark catalysis.
Dissolved trace metal (Cu, Cd, Co, Ni, and Ag) distribution and Cu speciation in the southern Yellow Sea and Bohai Sea, China

Science.gov (United States)

Li, Li; Xiaojing, Wang; Jihua, Liu; Xuefa, Shi

2017-02-01

Trace metals play an important role in biogeochemical cycling in ocean systems. However, because the use of trace metal clean sampling and analytical techniques has been limited in coastal China, there are few accurate trace metal data for that region. This work studied spatial distribution of selected dissolved trace metals (Ag, Cu, Co, Cd, and Ni) and Cu speciation in the southern Yellow Sea (SYS) and Bohai Sea (BS). In general, the average metal (Cu, Co, Cd, and Ni) concentrations found in the SYS were lower by a factor of two than those in BS, and they are comparable to dissolved trace metal concentrations in coastal seawater of the United States and Europe. Possible sources and sinks and physical and biological processes that influenced the distribution of these trace metals in the study region were further examined. Close relationships were found between the trace metal spatial distribution with local freshwater discharge and processes such as sediment resuspension and biological uptake. Ag, owing to its extremely low concentrations, exhibited a unique distribution pattern that magnified the influences from the physical and biological processes. Cu speciation in the water column showed that, in the study region, Cu was strongly complexed with organic ligands and concentrations of free cupric ion were in the range of 10-12.6-10-13.2 mol L-1. The distribution of Cu-complexing ligand, indicated by values of the side reaction coefficient α', was similar to the Chl a distribution, suggesting that in situ biota production may be one main source of Cu-complexing organic ligand.
Tailoring Graphene Morphology and Orientation on Cu(100), Cu(110), and Cu(111)

Science.gov (United States)

Jacobberger, Robert; Arnold, Michael

2013-03-01

Graphene CVD on Cu is phenomenologically complex, yielding diverse crystal morphologies, such as lobes, dendrites, stars, and hexagons, of various orientations. We present a comprehensive study of the evolution of these morphologies as a function of Cu surface orientation, pressure, H2:CH4, and nucleation density. Growth was studied on ultra-smooth, epitaxial Cu films inside Cu enclosures to minimize factors that normally complicate growth. With low H2:CH4, Mullins-Sekerka instabilities propagate to form dendrites, indicating transport limited growth. In LPCVD, the dendrites extend hundreds of microns in the 100, 111, and 110 directions on Cu(100), (110), and (111) and are perturbed by twin boundaries. In APCVD, multiple preferred dendrite orientations exist. With increasing H2:CH4, the dendritic nature of growth is suppressed. In LPCVD, square, rectangle, and hexagon crystals form on Cu(100), (110) and (111), reflecting the Cu crystallography. In APCVD, the morphology becomes hexagonal on each surface. If given ample time, every growth regime yields high-quality monolayers with D:G Raman ratio rationally tailor the graphene crystal morphology and orientation.
Processing of W-Cu functionally graded materials (FGM) through the powder metallurgy route: application as plasma facing components for ITER-like thermonuclear fusion reactor

International Nuclear Information System (INIS)

Raharijaona, J.J.

2009-11-01

The aim of this study was to study and optimize the sintering of W-Cu graded composition materials, for first wall of ITER-like thermonuclear reactor application. The graded composition in the material generates graded functional properties (Functionally Graded Materials - FGM). Rough thermomechanical calculations have shown the interest of W-Cu FGM to improve the lifetime of Plasma Facing Components (PFC). To process W-Cu FGM, powder metallurgy route was analyzed and optimized from W-CuO powder mixtures. The influence of oxide reduction on the sintering of powder mixtures was highlighted. An optimal heating treatment under He/H 2 atmosphere was determined. The sintering mechanisms were deduced from the analysis of the effect of the Cu-content. Sintering of W-Cu materials with a graded composition and grain size has revealed two liquid migration steps: i) capillary migration, after the Cu-melting and, ii) expulsion of liquid, at the end of sintering, from the dense part to the porous part, due to the continuation of W-skeleton sintering. These two steps were confirmed by a model based on capillary pressure calculation. In addition, thermal conductivity measurements were conducted on sintered parts and showed values which gradually increase with the Cu-content. Hardness tests on a polished cross-section in the bulk are consistent with the composition profiles obtained and the differential grain size. (author)
Ultrasonic friction power during thermosonic Au and Cu ball bonding

International Nuclear Information System (INIS)

Shah, A; Mayer, M; Zhou, Y; Qin, I; Huynh, C; Meyer, M

2010-01-01

The ultrasonic friction power during thermosonic ball bonding with Au and Cu wires, both 25 μm in diameter, is derived with an improved method from experimental measurements during the bonding process. Experimental data include the current delivered to the ultrasonic transducer and the tangential force measured using piezoresistive microsensors integrated close to the Al bonding pad. The improvement results from a new, more accurate method to derive the mechanical compliance of the ultrasonic system. The method employs a bond process modification in which the ultrasonic current is ramped up sequentially in three steps. In the first two steps, the ultrasonic current is set to levels that are too low to cause sliding. The bonding takes place during the third step, when the current is ramped up to the optimum value required for making good quality bonds. The ultrasonic compliance values are derived from the first two steps and are 8.2 ± 0.5 μm N -1 and 7.7 ± 0.5 μm N -1 for the Au and Cu processes, respectively. These values are determined within an average error estimate of ±6%, substantially lower than the ±10% estimated with a previously reported method. The ultrasonic compliance in the case of Au is 6% higher due to the lower elastic modulus of Au compared with that of Cu. Typical maximum values of relative sliding amplitude of ultrasonic friction at the interface are 655 nm and 766 nm for the Au and Cu processes. These values are 81% of the free-air vibration amplitude of the bonding capillary tip for the respective ultrasonic current settings. Due to bond growth, which damps relative motion between the ball and the pad, the final relative amplitude at the bond interface is reduced to 4% of the equivalent free-air amplitude. Even though the maximum value of relative amplitude is 17% higher in the Cu process compared with the Au process, the average total interfacial sliding is 519 μm in the Cu process, which is 31% lower than that in the Au process (759 �
Aluminum doping of CuInSe{sub 2} synthesized by solution process and its effect on structure, morphology, and bandgap tuning

Energy Technology Data Exchange (ETDEWEB)

Yan, Zhi; Deng, Weizhi; Zhang, Xia; Yuan, Qian; Deng, Peiran; Sun, Lei [Material Engineering College, Shanghai University of Engineering Science (China); Liang, Jun [School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen University Town (China)

2014-11-15

Al-doped CuInSe{sub 2} material is prepared by a low-cost wet chemical process. The key properties of Al-doped CuInSe{sub 2} as a successful solar cell material are investigated, such as crystal structure, morphology, optical properties, and bandgap. In situ X-ray diffraction measurements indicate that the doping of Al has induced noticeable lattice distortion. The material shows excellent thermal stability up to 600 C annealing temperature. By increasing the Al-doping concentration, the crystal unit-cell parameter of the material becomes smaller and the change of crystal structure leads to an increase of the grain size and surface roughness. The bandgap of Al-doped CuInSe{sub 2} can be continuously tuned in a range of 1.07-1.67 eV as Al/(Al + In) content ratio varies from 0 to 0.49. Finally, the effect mechanism on the properties of CuInSe{sub 2} after Al doping is discussed based on the ionic radius, crystal structure, and bonding state. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Self-organized antireflection CuIn(S,Se)_2 nano-protrusions on flexible substrates by ion erosion based on CuInS_2 nanocrystal precursor inks

International Nuclear Information System (INIS)

Yen, Yu-Ting; Wang, Yi-Chung; Chen, Chia-Wei; Tsai, Hung-Wei; Chen, Yu-Ze; Hu, Fan; Chueh, Yu-Lun

2015-01-01

Highlights: • CuIn(S,Se)_2 nano-protrusions were demonstrated on 36-cm"2 flexible substrates. • Nano-protrusions were created by ion erosion on selenized CuInS_2 nanocrystal precursor inks. • Tilt orientations and remarkable anti-reflectance characteristics of nano-protrusions can be precisely controlled. - Abstract: In this work, an approach to achieve surface nano-protrusions on a chalcopyrite CuIn(S,Se)_2 thin film was demonstrated. Home-made CuInS_2 nanocrystals with average diameter of 20 nm were prepared and characterized. By applying ion erosion process on the CuIn(S,Se)_2 film, large-area self-aligned nano-protrusions can be formed. Interestingly, the process can be applied on flexible substrate where the CuIn(S,Se)_2 film remains intact with no visible cracking after several bending tests. In addition, reflectance spectra reveal the extraordinary anti-reflectance characteristics of nano-protrusions on the CuIn(S,Se)_2 film with the incident light from 350 to 2000 nm. A 36-cm"2 CuIn(S,Se)_2 film with nano-protrusions on flexible molybdenum foil substrate has been demonstrated, which demonstrated the feasibility of developing low cost with a high optical absorption CuIn(S,Se)_2 flexible thin film.
Development of a Low-Cost TiO2/CuO/Cu Solar Cell by using Combined Spraying and Electroplating Method

Directory of Open Access Journals (Sweden)

Mamat Rokhmat

2018-03-01

Full Text Available A simple method is proposed to develop a low-cost TiO2/CuO/Cu based solar cell. The cell is made by employing a lower grade (technical grade of TiO2 as the active material. CuO powder is synthesized using a wet chemical method and mixed with TiO2 powder to give impurity to the TiO2. A layer of TiO2/CuO is then deposited onto fluorin-doped tin oxide (FTO by spraying. Copper particles are grown on the spaces between the TiO2 and/or CuO particles by electroplating for more feasible electron migration. The TiO2/CuO/Cu solar cell is finalized by sandwiching a polymer electrolyte between the film and the counter electrode. Current-voltage measurement was performed for various parameters, such as the molarity of NaOH for producing CuO particles, the weight ratio of CuO over TiO2, and the current in the electroplating process. A highest efficiency of 1.40% and a fill factor of 0.37 were achieved by using this combined spray and electroplating method.
Synthesis and densification of Cu-coated Ni-based amorphous composite powders

International Nuclear Information System (INIS)

Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

2007-01-01

Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv
Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

Energy Technology Data Exchange (ETDEWEB)

Li Beizhan; Zhou Difan; Xu Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng Zigang [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Izumi, Mitsuru, E-mail: izumi@kaiyodai.ac.jp [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

2012-11-20

This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.
Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

Science.gov (United States)

Li, Beizhan; Zhou, Difan; Xu, Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng, Zigang; Izumi, Mitsuru

2012-11-01

This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.
Y{sub 2}BaCuO{sub 5} particle distribution in YBa{sub 2}Cu{sub 3}O{sub 7-y} grains of melt growth processed YBCO oxides; Y{sub 2}BaCuO{sub 5}-Partikelverteilung in YBa{sub 2}Cu{sub 3}O{sub 7-y}-Koernern durch das Melt-Growth-Verfahren verarbeiteter YBCO-Oxide

Energy Technology Data Exchange (ETDEWEB)

Kim, Chan-Joong; Park, Soon-Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of). Neutron Science Div.; Park, Hai-Woong [Korea Univ. of Technology and Education, Chungnam (Korea, Republic of). College of Energy, Materials and Chemical Engineering

2013-02-01

Y{sub 2}BaCuO{sub 5} (Y211) particle distribution within YBa{sub 2}Cu{sub 3}O{sub 7-y} (Y123) grains of YBCO samples melt growth (MG) processed was examined. To understand the processing variables on the Y211 distribution, a cooling rate (R{sub C}=1 K/h to R{sub C}=20 K/h) through a peritectic temperature (T{sub p} = 1010 C), a precursor powder size and composition were changed. Two different Y211 distributions (a linear x-like track and planar butterfly-like pattern) were observed, depending on the processing variables. The linear x-like Y211 tracks were observed in the Y123 samples prepared using a stoichiometric Y123 precursor, whereas the planar butterfly-like Y211 patterns were observed in the Y{sub 1.8}Ba{sub 2.4}Cu{sub 3.4}O{sub 7-d} (Y1.8) samples prepared using an Y211-excess composition precursor. The track and planar Y211 patterns were clearer at lower R{sub C} (slower growth rate of Y123 grains) and for the smaller Y211 particles. In contrast, the random Y211 distribution was dominant at the higher R{sub C} and for the larger Y211 particles. The Y211 distribution patterns in the Y123 grains were explained in terms of the interfacial energy difference among growing Y123 fronts. (orig.)
Degradation of contaminants by Cu{sup +}-activated molecular oxygen in aqueous solutions: Evidence for cupryl species (Cu{sup 3+})

Energy Technology Data Exchange (ETDEWEB)

Feng, Yong, E-mail: fengy@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Lee, Po-Heng, E-mail: phlee@polyu.edu.hk [Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Wu, Deli, E-mail: wudeli@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Zhou, Zhengyuan, E-mail: zzy247@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Li, Hangkong, E-mail: hangkong@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Shih, Kaimin, E-mail: kshih@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

2017-06-05

Highlights: • Sulfadiazine and methylene blue were nearly completely degraded by Cu{sup +}-O{sub 2} oxidation. • Reaction of Cu{sup +} and hydrogen peroxide produced Cu{sup 3+} as the major active species. • 5,5-dimethyl-2-hydroxypyrrolidine-N-oxyl (DMPO-OH) was found in the reaction process. • Benzoic acid and electron paramagnetic resonance are not capable to differentiate Cu{sup 3+} and ·OH. - Abstract: Copper ions (Cu{sup 2+} and Cu{sup +}) have shown potential as Fenton-like activators for the circumneutral removal of organic contaminants from aqueous solutions. However, the major active species (cupryl species (Cu{sup 3+}) versus hydroxyl radical (·OH)) produced during the activation of hydrogen peroxide by Cu{sup +} remain unclear. In this study, Cu{sup +}-O{sub 2} oxidation, in which hydrogen peroxide is produced via the activated decomposition of dissolved molecular oxygen, was used to degrade sulfadiazine, methylene blue, and benzoic acid. The results showed that both sulfadiazine and methylene blue could be efficiently degraded by Cu{sup +}-O{sub 2} oxidation in a wide effective pH range from 2.0 to 10.0. Quenching experiments with different alcohols and the effect of Br{sup −} suggested that Cu{sup 3+} rather than ·OH was the major active species. Electron paramagnetic resonance detected 5,5-dimethyl-2-hydroxypyrrolidine-N-oxyl (DMPO-OH), which was probably produced by the oxidation of DMPO by Cu{sup 3+} or ·OH formed as a product of Cu{sup 3+} decomposition. 4-hydroxybenzoic acid was produced during the degradation of benzoic acid by Cu{sup 3+}. The findings of this study may help to explain the inconsistency regarding the dominant active species produced by the interaction of Cu{sup +} and hydrogen peroxide.
Fabrication and tensile properties of rapidly solidified Cu-10wt. %Ni alloy. [Cu-10Ni

Energy Technology Data Exchange (ETDEWEB)

Baril, D; Angers, R; Baril, J [Dept. of Mining and Metallurgy, Laval Univ., Ste-Foy, Quebec (Canada)

1992-10-15

Cu-10wt.%Ni ribbons were produced by melt spinning and cut into small particles with a blade cutter mill. The powders were then hot consolidated to full density by hot pressing followed by hot extrusion. Tensile properties of the resulting pieces were measured. Cu-10wt.%Ni cast ingots were also hot extruded and mechanically tested to compare with the rapidly solidified alloy and to evaluate the possible benefits brought by the rapid solidification process.
W-Cu gradient materials - processing, properties and application possibilities

International Nuclear Information System (INIS)

Joensson, M.; Kieback, B.

2001-01-01

The functionally graded material (FGM) of tungsten with its high thermal and mechanical resistance and copper with its very high thermal and electrical conductivity and ductility expands the application fields of this material in the direction of extreme demands such as plasma facing components in fusion reactors. The PM-production of W-Cu-gradients recommends itself because of the possibility to form the gradient by the mixing of powder components, but is also demanding because of the differences in their sintering behavior and thermal expansions. W-Gu-gradient samples of different concentration profiles have been formed in layers by powder stacking in a die and continuously by centrifugal powder forming. The consolidation routes were determined by the concentration areas of the gradients and encompass liquid phase sintering, pressure assisted solid phase sintering and the application of coated Tungsten powder and sintering additives. The microstructure and the concentration profiles of the samples have been investigated metaliographically and by EDX. The influence of processing and the gradient profile of the properties have been characterized by TRS and the investigation of residual thermal stresses by neutron diffraction. (author)
Cu deficiency in multi-stage co-evaporated Cu(In,Ga)Se{sub 2} for solar cells applications: Microstructure and Ga in-depth alloying

Energy Technology Data Exchange (ETDEWEB)

Caballero, R., E-mail: raquel.caballero@helmholtz-berlin.de [Helmholtz Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Izquierdo-Roca, V. [M-2E/XaRMAE/IN2UB, Departament d' Electronica, Universitat de Barcelona, C. Marti i Franques 1, 08028 Barcelona (Spain); Fontane, X. [IREC, Catalonia Institute for Energy Research, C. Joseph Pla 2 B2, 08019 Barcelona (Spain); Kaufmann, C.A. [Helmholtz Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Alvarez-Garcia, J. [Centre de Recerca i Investigacio de Catalunya (CRIC), Trav. de Gracia 108, 08012 Barcelona (Spain); Eicke, A. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung, Industriestrasse 6, 70565 Stuttgart (Germany); Calvo-Barrio, L. [Lab. Analisis de Superficies, SCT, Universitat de Barcelona, Lluis Sole i Sabaris 1-3, 08028 Barcelona (Spain); Perez-Rodriguez, A. [M-2E/XaRMAE/IN2UB, Departament d' Electronica, Universitat de Barcelona, C. Marti i Franques 1, 08028 Barcelona (Spain)] [IREC, Catalonia Institute for Energy Research, C. Joseph Pla 2 B2, 08019 Barcelona (Spain); Schock, H.W. [Helmholtz Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Morante, J.R. [M-2E/XaRMAE/IN2UB, Departament d' Electronica, Universitat de Barcelona, C. Marti i Franques 1, 08028 Barcelona (Spain)] [IREC, Catalonia Institute for Energy Research, C. Joseph Pla 2 B2, 08019 Barcelona (Spain)

2010-05-15

The objective of this work is to study the influence of the maximum Cu content during the deposition of Cu(In,Ga)Se{sub 2} (CIGSe) by multi-stage co-evaporation on the phases present in the final film, the film structure and the electrical properties of resulting solar cell devices. The variation of the composition is controlled by the Cu content in stage 2 of the deposition process. The different phases are identified by Raman spectroscopy. The in-depth Ga gradient distribution is investigated by in-depth resolved Raman scattering and secondary neutral mass spectroscopy. The morphology of the devices is studied by scanning electron microscopy. Efficiencies of 9.2% are obtained for ordered-vacancy-compound-based cells with a Cu/(In + Ga) ratio = 0.35, showing the system's flexibility. This work supports the current growth model: a small amount of Cu excess during the absorber process is required to obtain a quality microstructure and high performance devices.
Properties of different temperature annealed Cu(In,Ga)Se{sub 2} and Cu(In,Ga){sub 2}Se{sub 3.5} films prepared by RF sputtering

Energy Technology Data Exchange (ETDEWEB)

Yu Zhou; Liu Lian; Yan Yong; Zhang Yanxia; Li Shasha; Yan Chuanpeng; Zhang Yong [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education of China, Superconductivity and New Energy R and D Center (SNERDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); Zhao Yong, E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education of China, Superconductivity and New Energy R and D Center (SNERDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)

2012-11-15

Highlights: Black-Right-Pointing-Pointer The Cu(In,Ga)Se{sub 2} and Cu(In,Ga)2Se{sub 3.5} films follow different process to form CIGS phase. Black-Right-Pointing-Pointer Composition loss of the annealed Cu(In,Ga)Se{sub 2} and Cu(In,Ga){sub 2}Se{sub 3.5} films are different. Black-Right-Pointing-Pointer Hexagonal CuSe phase exhibits unique transport feature. Black-Right-Pointing-Pointer Conductivity of the CIGS films is affected by the 'variable range hopping' mechanism. - Abstract: We have investigated the effect of annealing temperature on structural, compositional, electrical properties of the one-step RF sputtered Cu(In,Ga)Se{sub 2} and Cu(In,Ga){sub 2}Se{sub 3.5} films. After the annealing at various temperatures, loss of Se element is significant for the Cu(In,Ga)Se{sub 2} films and meanwhile composition of the annealed Cu(In,Ga){sub 2}Se{sub 3.5} films keeps almost constant. The as-deposited Cu(In,Ga)Se{sub 2} and Cu(In,Ga){sub 2}Se{sub 3.5} films show amorphous structure and they follow different transformation process to form chalcopyrite structure. Electrical conductivity of the annealed CIGS films related to their chemical composition. Cu(In,Ga)Se{sub 2} films annealed at 150 Degree-Sign C show unique electron transport mechanism for the formation of hexagonal CuSe phase. Electrical conductivity of the chalcopyrite structure films are dominated by the 'variable range hopping' transport mechanism. The annealed Cu(In,Ga){sub 2}Se{sub 3.5} films present higher density of disorders than the annealed Cu(In,Ga)Se{sub 2} films for their significant Cu deficient composition.
Heating induced microstructural changes in graphene/Cu nanocomposites

International Nuclear Information System (INIS)

Solá, F; Niu, J; Xia, Z H

2013-01-01

Dynamic heating experiments on graphene/Cu nanocomposites by in situ scanning electron microscopy were conducted to observe the evolution of the morphology and size of the Cu nanoparticles. Microstructural characterization showed that the graphene/Cu nanocomposites system consists of graphene sheets decorated with Cu-based nanoparticles with different chemistries (Cu, Cu 2 O), shapes (cube, rod, triangle, etc) and sizes. Evidence of neck evolution, coalescence, sublimation and Ostwald ripening were observed. Interestingly, some of the events occurred at the edges of the graphene sheets. The quantitative data of necking evolution deviates from the classical continuum theory indicating that intrinsic faceting and the shape of the nanoparticles played an important role in the necking process. This was supported by molecular dynamics simulations. Experimental data of liquid-spherical nanoparticles on graphene suggested that Cu did not wet graphene. Based on sublimation experiments and surface stability, we propose that graphene decorated with Cu nanoparticles enclosed by {111} facets are the most stable nanocomposite at high temperatures. The growth mechanism of nanoparticles on graphene is discussed.
Microstructure within domains of melt-processed YBa2Cu3O7-x superconductors

International Nuclear Information System (INIS)

Alexander, K.B.; Goyal, A.; Kroeger, D.M.; Selvamanickam, V.; Salama, K.

1992-01-01

The microstructure within single domains of melt-processed YBa 2 Cu 3 O 7-x (1:2:3) material has been examined. Rather than composing a ''brick-wall'' structure, the stacked, parallel platelets within the domains are actually portions of a single crystal. A growth mechanism is proposed that is consistent with the observed microstructural features. The anisotropic nature of the growth of 1:2:3 results in gaps separating the platelets. The gaps, however, terminate within domains, resulting in interconnected single-crystalline material. The absence of weak-link behavior for current flow along the c axis and the high critical-current densities observed within domains of melt-processed 1:2:3 material are readily explained by the fact that current flow is solely through single-crystalline material
Cu-ZSM-5, Cu-ZSM-11, and Cu-ZSM-12 Catalysts for Direct NO Decomposition

DEFF Research Database (Denmark)

Kustova, Marina; Kustov, Arkadii; Christiansen, Sofie E.

2006-01-01

Cu-ZSM-5 has for many years been recognized as a unique catalyst for direct NO decomposition. Here, it is discovered that both Cu-ZSM-11 and Cu-ZSM-12 are about twice as active as Cu-ZSM-5. This difference is attributed to the active sites located almost exclusively in the straight zeolite pores...
Toxic effects of low concentrations of Cu on nodulation of cowpea (Vigna unguiculata)

International Nuclear Information System (INIS)

Kopittke, Peter M.; Dart, Peter J.; Menzies, Neal W.

2007-01-01

Although Cu is phytotoxic at Cu 2+ activities as low as 1-2 μM, the effect of Cu 2+ on the nodulation of legumes has received little attention. The effect of Cu 2+ on nodulation of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona) was examined in a dilute solution culture system utilising a cation exchange resin to buffer solution Cu 2+ . The nodulation process was more sensitive to increasing Cu 2+ activities than both shoot and root growth; whilst a Cu 2+ activity of 1.0 μM corresponded to a 10% reduction in the relative yield of the shoots and roots, a Cu 2+ activity of 0.2 μM corresponded to a 10% reduction in nodulation. This reduction in nodulation with increasing Cu 2+ activity was associated with an inhibition of root hair formation in treatments containing ≥0.77 μM Cu 2+ , rather than to a reduction in the size of the Rhizobium population. - The nodulation process was more sensitive to increasing Cu 2+ activities than either shoot or root growth
High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer.

Science.gov (United States)

Sun, Weihai; Li, Yunlong; Ye, Senyun; Rao, Haixia; Yan, Weibo; Peng, Haitao; Li, Yu; Liu, Zhiwei; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin; Bian, Zuqiang; Huang, Chunhui

2016-05-19

During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid ( PSS) as the hole transport material (HTM), the hydrophilicity of the PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm(-2) and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the PSS layer, indicating that CuOx could be a promising HTM for replacing PSS in inverted planar heterojunction perovskite solar cells.
Influence of Material Coating on the Heat Transfer in a Layered Cu-SiC-Cu Systems

Directory of Open Access Journals (Sweden)

Strojny-Nędza A.

2017-06-01

Full Text Available This paper describes the process of obtaining Cu-SiC-Cu systems by way of spark plasma sintering. A monocrystalline form of silicon carbide (6H-SiC type was applied in the experiment. Additionally, silicon carbide samples were covered with a layer of tungsten and molybdenum using chemical vapour deposition (CVD technique. Microstructural examinations and thermal properties measurements were performed. A special attention was put to the metal-ceramic interface. During annealing at a high temperature, copper reacts with silicon carbide. To prevent the decomposition of silicon carbide two types of coating (tungsten and molybdenum were applied. The effect of covering SiC with the aforementioned elements on the composite’s thermal conductivity was analyzed. Results were compared with the numerical modelling of heat transfer in Cu-SiC-Cu systems. Certain possible reasons behind differences in measurements and modelling results were discussed.
Solidification of Bi2Sr2Ca1Cu2Oy and Bi2Sr1.75Ca0.25CuOy

International Nuclear Information System (INIS)

Holesinger, T.G.; Miller, D.J.; Viswanathan, H.K.; Chumbley, L.S.

1993-01-01

The solidification processes for the compositions Bi 2 Sr 2 CaCu 2 O y (2212) and Bi 2 Sr 1.75 Ca 0.25 CuO y (2201) were determined as a function of oxygen partial pressure. During solidification in argon, the superconducting phases were generally not observed to form for either composition. In both cases, the solidus is lowered to approximately 750 degree C. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 2-x Ca x O y (22x) and Cu 2 O while solidification of Bi 2 Sr 2 CaCu 2 O y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 3-x Ca x O y (23x) and Cu 2 O. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in O 2 resulted in large grains of 2201 interspersed with small regions containing the eutectic structure of 22x and CuO/Cu 2 O. Solidification of Bi 2 Sr 2 CaCu 2 O y in partial pressures of 1%, 20%, and 100% oxygen resulted in multiphase samples consisting of 2212, 2201, some alkaline-earth cuprates, and both divorced eutectic structures found during solidification in Ar. For both compositions, these latter structures can be attributed to oxygen deficiencies present in the melt regardless of the overpressure of oxygen. These eutectic structures are unstable and convert into the superconducting phases during subsequent anneals in oxygen. The formation process of the 2212 phase during solidification from the melt was determined to proceed through an intermediate state involving the 2201 phase
Self-doping processes between planes and chains in the metal-to-superconductor transition of YBa2Cu3O6.9.

Science.gov (United States)

Magnuson, M; Schmitt, T; Strocov, V N; Schlappa, J; Kalabukhov, A S; Duda, L-C

2014-11-12

The interplay between the quasi 1-dimensional CuO-chains and the 2-dimensional CuO2 planes of YBa(2)Cu(3)O(6+x) (YBCO) has been in focus for a long time. Although the CuO-chains are known to be important as charge reservoirs that enable superconductivity for a range of oxygen doping levels in YBCO, the understanding of the dynamics of its temperature-driven metal-superconductor transition (MST) remains a challenge. We present a combined study using x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS) revealing how a reconstruction of the apical O(4)-derived interplanar orbitals during the MST of optimally doped YBCO leads to substantial hole-transfer from the chains into the planes, i.e. self-doping. Our ionic model calculations show that localized divalent charge-transfer configurations are expected to be abundant in the chains of YBCO. While these indeed appear in the RIXS spectra from YBCO in the normal, metallic, state, they are largely suppressed in the superconducting state and, instead, signatures of Cu trivalent charge-transfer configurations in the planes become enhanced. In the quest for understanding the fundamental mechanism for high-Tc-superconductivity (HTSC) in perovskite cuprate materials, the observation of such an interplanar self-doping process in YBCO opens a unique novel channel for studying the dynamics of HTSC.
Processing and properties of Cu based micro- and nano-composites

Indian Academy of Sciences (India)

The decrease in structural weight, increase in creep strength, high fatigue strength, high .... cate Al2O3 particles while the white portion corresponds to Cu matrix ..... preceding the frac- ture and rapid crack growth accompanied by loud noise ...

High-strength high-conductivity Cu-Nb microcomposite sheet fabricated via multiple roll bonding

International Nuclear Information System (INIS)

Jha, S.C.; Delagi, R.G.; Forster, J.A.; Krotz, P.D.

1993-01-01

Copper-niobium microcomposites are a new class of high-strength high-conductivity materials that have attractive properties for room- and elevated-temperature applications. Since Nb has little solid solubility in Cu, addition of Nb to Cu does not affect its conductivity. Copper-niobium microcomposites are melted and cast so that the microstructure of cast Cu-Nb ingots consists of 1- to 10 μm Nb dendrites uniformly distributed within the copper matrix. Extensive wire drawing with a true processing strain (η> 12) of Cu-Nb alloy leads to refinement and elongation of Nb dendrites into 1- to 10 nm-thick filaments. The presence of such fine Nb filaments causes a significant increase in the strength of Cu-Nb wires. The tensile strength of heavily drawn Cu-Nb wires was determined to be significantly higher than the values predicted by the rule of mixtures. This article reports the fabrication of high-strength Cu-Nb microcomposite sheet by multiple roll bonding. It is difficult and impractical to attain high processing strains (η>3) by simple cold rolling. In most practical cold-rolling operation, the thickness reduction does not exceed 90 pct (η ≅2). Therefore, innovative processing is required to generate high strength in Cu-Nb microcomposite sheet. Multiple roll bonding of Cu-Nb has been utilized to store high processing strain ( η>10) in the material and refine the Nb particle size within the copper matrix. This article describes the microstructure, mechanical properties, and thermal stability of roll-bonded Cu-Nb microcomposite sheet
Nanostructured CuO thin film electrodes prepared by spray pyrolysis: a simple method for enhancing the electrochemical performance of CuO in lithium cells

International Nuclear Information System (INIS)

Morales, Julian; Sanchez, Luis; Martin, Francisco; Ramos-Barrado, Jose R.; Sanchez, Miguel

2004-01-01

Nanostructured CuO thin films were prepared by using a spray pyrolysis method, copper acetate as precursor and stainless steel as substrate. The textural and structural properties of the films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The SEM images revealed thorough coating of the substrate and thickness of 450-1250 nm; the average particle size as determined from the AFM images ranged from 30 to 160 nm. The XRD patterns revealed the formation of CuO alone and the XPS spectra confirmed the presence of Cu 2+ as the main oxidation state on the surface. The films were tested as electrodes in lithium cells and their electrochemical properties evaluated from galvanostatic and step potential electrochemical spectroscopy (SPES) measurements. The discharge STEP curves exhibited various peaks consistent with the processes CuO Cu 2 O Cu and with decomposition of the electrolyte, a reversible process in the light of the AFM images. The best electrode exhibited capacity values of 625 Ah kg -1 over more than 100 cycles. This value, which involves a CuO Cu reversible global reaction, is ca. 50% higher than that reported for bulk CuO. The nanosize of the particles and the good adherence of the active material to the substrate are thought to be the key factors accounting for the enhanced electrochemical activity found
Practical UXO Classification: Enhanced Data Processing Strategies for Technology Transition - Fort Ord: Dynamic and Cued Metalmapper Processing and Classification

Science.gov (United States)

2017-06-06

information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this...ms. 4 2.2 CLASSIFICATION Target classification is usually carried out using cued interrogation data acquired over anomalies initially...identified in the detection data. These cued interrogations eliminate relative positional errors by acquiring data with a stationary sensor. The multi-static
In situ observation of Cu-Ni alloy nanoparticle formation by X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy: Influence of Cu/Ni ratio

DEFF Research Database (Denmark)

Wu, Qiongxiao; Duchstein, Linus Daniel Leonhard; Chiarello, Gian Luca

2014-01-01

Silica-supported, bimetallic Cu-Ni nanomaterials were prepared with different ratios of Cu to Ni by incipient wetness impregnation without a specific calcination step before reduction. Different in situ characterization techniques, in particular transmission electron microscopy (TEM), X-ray...... diffraction (XRD), and X-ray absorption spectroscopy (XAS), were applied to follow the reduction and alloying process of Cu-Ni nanoparticles on silica. In situ reduction of Cu-Ni samples with structural characterization by combined synchrotron XRD and XAS reveals a strong interaction between Cu and Ni species......, which results in improved reducibility of the Ni species compared with monometallic Ni. At high Ni concentrations silica-supported Cu-Ni alloys form a homogeneous solid solution of Cu and Ni, whereas at lower Ni contents Cu and Ni are partly segregated and form metallic Cu and Cu-Ni alloy phases. Under...
Modifikasi Zeolit Dengan Tembaga (Cu) Dan Uji Sifat Katalitiknya Pada Reaksi Esterifikasi

OpenAIRE

Arjek, Orien Claudia Handayani; Fatimah, Is

2017-01-01

Zeolite modification with Cu has been conducted. Material modification is done by impregnating Cu through a zeolite powder reflux process with CuSO4.5H2O solution so that theoretical Cu concentration is 5% followed by oxidation and reduction of solids. Material characterization was performed by x-ray diffraction analysis (XRD), Fourier Transform Infra-Red (FTIR) and acidity testing of Cu/Zeolite catalyst.The results showed that the crystallinity level of Cu/Zeolite did not change significantl...
Development of cold sprayed Cu coating for canister

International Nuclear Information System (INIS)

Kim, Hyung Jun; Kang, Yoon Ha

2010-01-01

Cold sprayed Cu deposition was studied for the application of outer part of canister for high level nuclear waste. Five commercially available pure Cu powders were analyzed and sprayed by high pressure cold spray system. Electrochemical corrosion test using potentiostat in 3.5% NaCl solution was conducted as well as microstructural analysis including hardness and oxygen content measurements. Overall evaluation of corrosion performance of cold sprayed Cu deposition is inferior to forged and extruded Cu plates, but some of Cu depositions are comparable to Cu plates. The simulated corrosion test in 200m underground cave is still in progress. The effect of cold spray process parameters was also studied and the results show that the type of nozzle is the most important other than powder feed rate, spray distance, and scan speed. 1/10 scale miniature of canister was manufactured confirming that the production of full scale canister is possible
Low-temperature synthesis of CuFeO{sub 2} (delafossite) at 70 °C: A new process solely by precipitation and ageing

Energy Technology Data Exchange (ETDEWEB)

John, Melanie, E-mail: melanie.john@min.uni-muenchen.de [Section Mineralogy, Petrology & Geochemistry, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstr. 41, 80333 Munich (Germany); Heuss-Aßbichler, Soraya [Section Mineralogy, Petrology & Geochemistry, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstr. 41, 80333 Munich (Germany); Park, So-Hyun [Section Crystallography, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstr. 41, 80333 Munich (Germany); Ullrich, Aladin [Experimental Physics II, University of Augsburg, Universitätsstr. 1, 86159 Augsburg (Germany); Benka, Georg [Physics Department, Technical University Munich, James-Franck-Straße 1, 85748 Garching (Germany); Petersen, Nikolai [Section Geophysics, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstr. 41, 80333 Munich (Germany); Rettenwander, Daniel [Department of Materials Research & Physics, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg (Austria); Horn, Siegfried R. [Experimental Physics II, University of Augsburg, Universitätsstr. 1, 86159 Augsburg (Germany)

2016-01-15

This study presents a new low temperature synthesis method to obtain pure delafossite (Cu{sup 1+}Fe{sup 3+}O{sub 2}) at a temperature of 70 °C within 24 h. For the first time delafossite is synthesized solely by precipitation and subsequent ageing process and without usage of any additives controlling the oxidation state of copper. The synthesized material, called LT-delafossite, consists of pure Cu{sup 1+}Fe{sup 3+}O{sub 2} exclusive of any side products. Rietveld analysis confirms the presence of both 3R (space group (SG): R-3m) and 2H (SG: P6{sub 3}/mmc) polytypes in LT-delafossite. Electron microscopy images show nanometer-sized hexagonal plates with a diameter <500 nm and a thickness of <30 nm. Measurements of the magnetic susceptibility from 2 K to 350 K in zero-field show one peak ∼18.5 K, which is attributed to an AFM phase transition. Zero-field-cooled magnetization data between −14 T and +14 T at 2 K revealed an s-shape form around the origin having no remanent magnetization. - Highlights: • New process: low temperature synthesis of pure CuFeO{sub 2} nanoparticles. • Synthesis at 70 °C within 24 h solely by precipitation and ageing. • Nanoparticle characterization by XRD, FTIR, SEM, ICP–OES, TEM and Mößbauer. • Special magnetic properties of nano-sized CuFeO{sub 2} synthesized at low temperatures.
Antibacterial studies of novel Cu2WS4 ternary chalcogenide synthesized by hydrothermal process

Science.gov (United States)

Kannan, Selvaraj; Vinitha, Perumal; Mohanraj, Kannusamy; Sivakumar, Ganesan

2018-02-01

This is the first report for the synthesis of L-cysteine mediated Cu2WS4 nanoparticles for different temperatures by an inexpensive and less pollutive hydrothermal method. The as-synthesized particles were characterized by XRD, FTIR, FESEM, UV-vis diffuse reflectance and PL spectra technique respectively. The phase purity and structural confirmation were studied by X-ray powder diffraction technique. It is observed that the synthesis temperature affecting the crystalline size. The optical analysis of the Cu2WS4 nanoparticles showed direct band gap in the range of 2.1-2.3 eV. The intensity of the PL emission spectra decreases with increase of reaction temperature. The antibacterial performance of Cu2WS4 nanoparticles were investigated by agar well diffusion method and the results confirm that the antibacterial activity of Cu2WS4 against Gram-positive (B. subtilis, M. luteus) and Gram-negative (E. coli, P. aeruginosa and K. pneumoniae) bacteria.
Structural evolution, thermomechanical recrystallization and electrochemical corrosion properties of Ni-Cu-Mg amorphous coating on mild steel fabricated by dual-anode electrolytic processing

Energy Technology Data Exchange (ETDEWEB)

Abdulwahab, M., E-mail: mabdulwahab@abu.edu.ng [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Metallurgical and Materials Engineering, Ahmadu Bello University, Zaria (Nigeria); Fayomi, O.S.I., E-mail: ojosundayfayomi3@gmail.com [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Mechanical Engineering, Covenant University, Ota (Nigeria); Popoola, A.P.I., E-mail: popoolaapi@tut.ac.za [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa)

2016-07-01

Highlights: • The surface of the coat containing Ni-Cu-Mg alloy on mild steel have sufficiently enhanced the properties. • Isothermally treated composites demonstrated 45% increase in the micro-hardness and 79.6% corrosion resistance. • The thermal stability of the developed Ni-Cu-Mg thin films on mild steel was excellent. - Abstract: The electrolytic Ni-Cu based alloy coating with admixed interfacial blend of Mg have been successfully prepared on mild steel substrate by dual anode electroplating processes over a range of applied current density and dwell time. The electrocodeposition of Ni-Cu-Mg coating was investigated in the presence of other bath additives. The influence of deposition current on surface morphology, adhesion behavior, preferred crystal orientation, surface topography and electrochemical activity of Ni-Cu-Mg alloy coating on mild steel were systematically examined. The thermal stability of the developed composite materials was examined via isothermal treatment. Scanning electron microscope equipped with EDS, X-ray diffraction, Atomic force microscope, micro-hardness tester and 3 μmetrohm Potentiostat/galvanostat were used to compare untreated and isothermally treated electrocodeposited composite. The induced activity of the Ni-Cu-Mg alloy changed the surface modification and results to crystal precipitation within the structural interface by the formation of Cu{sub ,} Ni{sub 2}Mg{sub 3} phase. The obtained results showed that the introduction of Mg particles in the plating bath generally modified the surface and brings an increase in the hardness and corrosion resistance of Ni-Cu-Mg layers fabricated. Equally, isothermally treated composites demonstrated an improved properties indicating 45% increase in the micro-hardness and 79.6% corrosion resistance which further showed that the developed composite is thermally stable.
Carbon Supported Oxide-Rich Pd-Cu Bimetallic Electrocatalysts for Ethanol Electrooxidation in Alkaline Media Enhanced by Cu/CuOx

Directory of Open Access Journals (Sweden)

Zengfeng Guo

2016-04-01

Full Text Available Different proportions of oxide-rich PdCu/C nanoparticle catalysts were prepared by the NaBH4 reduction method, and their compositions were tuned by the molar ratios of the metal precursors. Among them, oxide-rich Pd0.9Cu0.1/C (Pd:Cu = 9:1, metal atomic ratio exhibits the highest electrocatalytic activity for ethanol oxidation reaction (EOR in alkaline media. X-ray photoelectron spectroscopy (XPS and high resolution transmission electron microscopy (HRTEM confirmed the existence of both Cu and CuOx in the as-prepared Pd0.9Cu0.1/C. About 74% of the Cu atoms are in their oxide form (CuO or Cu2O. Besides the synergistic effect of Cu, CuOx existed in the Pd-Cu bimetallic nanoparticles works as a promoter for the EOR. The decreased Pd 3d electron density disclosed by XPS is ascribed to the formation of CuOx and the spill-over of oxygen-containing species from CuOx to Pd. The low Pd 3d electron density will decrease the adsorption of CH3COads intermediates. As a result, the electrocatalytic activity is enhanced. The onset potential of oxide-rich Pd0.9Cu0.1/C is negative shifted 150 mV compared to Pd/C. The oxide-rich Pd0.9Cu0.1/C also exhibited high stability, which indicated that it is a candidate for the anode of direct ethanol fuel cells (DEFCs.
Use of Hopcalite derived Cu-Mn mixed oxide as Oxygen Carrier for Chemical Looping with Oxygen Uncoupling Process

OpenAIRE

Adánez-Rubio, Iñaki; Abad Secades, Alberto; Gayán Sanz, Pilar; Adánez-Rubio, Imanol; Diego Poza, Luis F. de; Garcia-Labiano, Francisco; Adánez Elorza, Juan

2016-01-01

Chemical-Looping with Oxygen Uncoupling (CLOU) is an alternative Chemical Looping process for the combustion of solid fuels with inherent CO2 capture. The CLOU process needs a material as oxygen carrier with the ability to give gaseous O2 at suitable temperatures for solid fuel combustion, e.g. copper oxide and manganese oxide. In this work, treated commercial Carulite 300® was evaluated as oxygen carrier for CLOU. Carulite 300® is a hopcalite material composed of 29.2 wt.% CuO and 67.4 wt.% ...
Optimization of the Hot Forging Processing Parameters for Powder Metallurgy Fe-Cu-C Connecting Rods Based on Finite Element Simulation

Science.gov (United States)

Li, Fengxian; Yi, Jianhong; Eckert, Jürgen

2017-12-01

Powder forged connecting rods have the problem of non-uniform density distributions because of their complex geometric shape. The densification behaviors of powder metallurgy (PM) connecting rod preforms during hot forging processes play a significant role in optimizing the connecting rod quality. The deformation behaviors of a connecting rod preform, a Fe-3Cu-0.5C (wt pct) alloy compacted and sintered by the powder metallurgy route (PM Fe-Cu-C), were investigated using the finite element method, while damage and friction behaviors of the material were considered in the complicated forging process. The calculated results agree well with the experimental results. The relationship between the processing parameters of hot forging and the relative density of the connecting rod was revealed. The results showed that the relative density of the hot forged connecting rod at the central shank changed significantly compared with the relative density at the big end and at the small end. Moreover, the relative density of the connecting rod was sensitive to the processing parameters such as the forging velocity and the initial density of the preform. The optimum forging processing parameters were determined and presented by using an orthogonal design method. This work suggests that the processing parameters can be optimized to prepare a connecting rod with uniform density distribution and can help to better meet the requirements of the connecting rod industry.
Effect of Cu{sup 2+}/Al{sup 3+} mole ratio on structure of Cu-Al bimetallic nanoparticles prepared by radiation induced method

Energy Technology Data Exchange (ETDEWEB)

Abedini, Alam; Larki, Farhad; Saion, Elias; Noroozi, Monir [Putra Malaysia Univ., Serdang, Selangor (Malaysia). Dept. of Physics

2013-07-15

Cu-Al bimetallic nanoparticles were synthesized by gamma irradiation technique in aqueous solutions containing metal chlorides as precursors, polyvinyl alcohol (PVA) as a capping agent, isopropanol as a radical scavenger, and distilled water as a solvent. The Cu-Al bimetallic nanoparticles were characterized by transmission electron microscopy (TEM), UV-visible absorption spectrometry, powder X-ray diffractometer (XRD), and Energy-dispersive X-ray spectroscopy (EDX). The TEM, XRD, EDX, and absorption analyses confirmed the formation of core-shell structure of Cu-Al bimetallic nanoparticles at lower Cu{sup 2+}/Al{sup 3+} mole ratio, and the formation of Cu-Al alloy nanoparticles at higher Cu{sup 2+}/Al{sup 3+} mole ratio. The TEM analysis for particle size and size distribution revealed that the average particle size of Cu-Al bimetallic nanoparticles decreased with the increase of absorbed dose. It may be explained due to the competition between nucleation and aggregation processes in the formation of metallic nanoparticles under irradiation. (orig.)
Comparison in processing routes by copper mold casting injection and suction in the Cu46Zr42Al7Y5 vitreous alloy

International Nuclear Information System (INIS)

Batalha, W.; Aliaga, L.C.R.; Bolfarini, C.; Botta, W.J.; Kiminami, C.S.

2014-01-01

To expand the application of glassy metals, the development of processing routes and compositions that allow the production of parts with dimensions of millimeters or even centimeters, is very important. The present work aims the contribution to the technological development of processing routes for the production of Cu-based bulk metallic glasses. Wedge-shaped samples of Cu 46 Zr 42 Al 7 Y 5 (atom percent) chemical composition were processed using copper mold casting by suction and injection. Characterization was made combining scanning electron microscopy, x-ray diffraction and differential scanning calorimetry. The critical amorphous thickness obtained by those two different routes was carefully observed. The suction route allow obtaining the best results with critical amorphous thickness about 8 mm. This result was analyzed considering the different extrinsic parameters to the glass forming ability of the alloy. (author)
Highly charged swelling mica reduces Cu bioavailability in Cu-contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Stuckey, Jason W. [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States); Neaman, Alexander [Facultad de Agronomia, P. Universidad Catolica de Valparaiso, Centro Regional de Estudios en Alimentos Saludables (Chile); Ravella, Ramesh; Komarneni, Sridhar [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States); Martinez, Carmen Enid [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States)], E-mail: cem17@psu.edu

2009-01-15

This is the first test of a highly charged swelling mica's (Na-2-mica) ability to reduce the plant-absorbed Cu in Cu-contaminated soils from Chile. Perennial ryegrass (Lolium perenne L.) was grown in two acid soils (Sector 2: pH 4.2, total Cu = 172 mg Cu kg{sup -1} and Sector 3: pH 4.2, total Cu = 112 mg Cu kg{sup -1}) amended with 0.5% and 1% (w/w) mica, and 1% (w/w) montmorillonite. At 10 weeks of growth, both mica treatments decreased the shoot Cu of ryegrass grown in Sector 2 producing shoot Cu concentrations above 21-22 mg Cu kg{sup -1} (the phytotoxicity threshold for that species), yet the mica treatments did not reduce shoot Cu concentrations when grown in Sector 3, which were at a typical level. The mica treatments improved shoot growth in Sector 3 by reducing free and extractable Cu to low enough levels where other nutrients could compete for plant absorption and translocation. In addition, the mica treatments improved root growth in both soils, and the 1% mica treatment reduced root Cu in both soils. This swelling mica warrants further testing of its ability to assist re-vegetation and reduce Cu bioavailability in Cu-contaminated surface soils. - In situ remediation of Cu-contaminated soils with a synthetic mica (Na-2-mica) will aid in re-vegetative efforts.
Toxic effects of low concentrations of Cu on nodulation of cowpea (Vigna unguiculata)

Energy Technology Data Exchange (ETDEWEB)

Kopittke, Peter M. [School of Land and Food Sciences, University of Queensland, St. Lucia, Qld 4072 (Australia)]. E-mail: p.kopittke@uq.edu.au; Dart, Peter J. [School of Land and Food Sciences, University of Queensland, St. Lucia, Qld 4072 (Australia); Menzies, Neal W. [School of Land and Food Sciences, University of Queensland, St. Lucia, Qld 4072 (Australia)

2007-01-15

Although Cu is phytotoxic at Cu{sup 2+} activities as low as 1-2 {mu}M, the effect of Cu{sup 2+} on the nodulation of legumes has received little attention. The effect of Cu{sup 2+} on nodulation of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona) was examined in a dilute solution culture system utilising a cation exchange resin to buffer solution Cu{sup 2+}. The nodulation process was more sensitive to increasing Cu{sup 2+} activities than both shoot and root growth; whilst a Cu{sup 2+} activity of 1.0 {mu}M corresponded to a 10% reduction in the relative yield of the shoots and roots, a Cu{sup 2+} activity of 0.2 {mu}M corresponded to a 10% reduction in nodulation. This reduction in nodulation with increasing Cu{sup 2+} activity was associated with an inhibition of root hair formation in treatments containing {>=}0.77 {mu}M Cu{sup 2+}, rather than to a reduction in the size of the Rhizobium population. - The nodulation process was more sensitive to increasing Cu{sup 2+} activities than either shoot or root growth.
Cu-Si bilayers as storage medium in optical recording

International Nuclear Information System (INIS)

Kuiper, A.E. T.; Vullers, R.J.M.; Pasquariello, D.; Naburgh, E.P.

2005-01-01

Instead of a phase change or a dye layer, a Cu/Si bilayer can be applied as the recording medium in a write-once Blu-ray Disc. The write process basically comprises the formation of a CuSi alloy containing 25-30 at. % Si, while any excess of Si is left behind as unreacted film. Auger analyses of the laser-written layers indicate that recording consists primarily of the diffusion of Si into Cu. The data allow for discrimination between the various models presented in literature for Cu/Si-based recording and to optimize the stack. Very low jitter levels of typically 4% proved to be achievable with equally thick films of Cu and Si as recording medium
Punicalagin Green Functionalized Cu/Cu2O/ZnO/CuO Nanocomposite for Potential Electrochemical Transducer and Catalyst

Science.gov (United States)

Fuku, X.; Kaviyarasu, K.; Matinise, N.; Maaza, M.

2016-09-01

A novel ternary Punica granatum L-Cu/Cu2O/CuO/ZnO nanocomposite was successfully synthesised via green route. In this work, we demonstrate that the green synthesis of metal oxides is more viable and facile compare to other methods, i.e., physical and chemical routes while presenting a potential electrode for energy applications. The prepared nanocomposite was characterised by both microscopic and spectroscopic techniques. High-resolution scanning electron microscopy (HRSEM) and X-ray diffraction (XRD) techniques revealed different transitional phases with an average nanocrystallite size of 29-20 mm. It was observed that the nanocomposites changed from amorphous-slightly crystalline Cu/Cu2O to polycrystalline Cu/Cu2O/CuO/ZnO at different calcination temperatures (room temperature-RT- 600 °C). The Cu/Cu2O/ZnO/CuO metal oxides proved to be highly crystalline and showed irregularly distributed particles with different sizes. Meanwhile, Fourier transform infrared (FTIR) spectroscopy confirmed the purity while together with ultraviolet-visible (UV-Vis) spectroscopy proved the proposed mechanism of the synthesised nanocomposite. UV-Vis showed improved catalytic activity of the prepared metal oxides, evident by narrow band gap energy. The redox and electrochemical properties of the prepared nanocomposite were achieved by cyclic voltammetry (CV), electrochemical impedance (EIS) and galvanostatic charge-discharge (GCD). The maximum specific capacitance ( C s) was calculated to be 241 F g-1 at 50 mV s-1 for Cu/Cu2O/CuO/ZnO nanoplatelets structured electrode. Moreover, all the CuO nanostructures reveal better power performance, excellent rate as well as long term cycling stability. Such a study will encourages a new design for a wide spectrum of materials for smart electronic device applications.
Bonding Be to Cu alloys using a proprietary Brush Wellman process and new results for bonding Be to AlBeMet

Energy Technology Data Exchange (ETDEWEB)

Dombrowski, D.E. [Brush Wellman Inc., Cleveland, OH (United States)

1998-01-01

A novel process has been investigated for bonding of beryllium to copper alloys. The process is compatible with current manufacturing capabilities and can be readily scaled up from laboratory to production scale. The effect of process variations on the bond are shown. Also shown are several new approaches for direct bonding of beryllium to an AlBeMet interlayer. Bond strengths of Be/AlBeMet 162/Cu alloy couples are presented. (author)
Synthesis and characterization of micrometer Cu/PVP architectures

International Nuclear Information System (INIS)

Luo, Huajuan; Zhao, Yanbao; Sun, Lei

2011-01-01

Graphical abstract: A simple method for the synthesis of novel micrometer flower-like Cu/PVP architectures was introduced. Highlights: → Micrometer flower-like copper/polyvinylpyrrolidone architectures were obtained by a simple chemical route. → The amount of N 2 H 4 ·H 2 O, the reaction temperature, the molar ratio of CuCl 2 to PVP and different molecular weights of PVP play an important role in the controlling the morphology of the Cu/PVP architectures. → A possible mechanism of the formation of Cu/PVP architectures was discussed. -- Abstract: Micrometer-sized flower-like Cu/polyvinylpyrrolidone (PVP) architectures are synthesized by the reduction of copper (II) salt with hydrazine hydrate in aqueous solution in the presence of PVP capping agent. The resulting Cu/PVP architectures are investigated by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The Cu/PVP flowers have uniform morphologies with an average diameter of 10 μm, made of several intercrossing plates. The formation of Cu/PVP flowers is a new kinetic control process, and the factors such as the amount of N 2 H 4 ·H 2 O, reaction temperature, molar ratio of CuCl 2 to PVP and molecular weight of PVP have significant effect on the morphology of Cu/PVP architectures. A possible mechanism of the formation of micrometer Cu/PVP architectures was discussed.

High-Performance Ink-Synthesized Cu-Gate Thin-Film Transistor with Diffusion Barrier Formation

Science.gov (United States)

Woo, Whang Je; Nam, Taewook; Oh, Il-Kwon; Maeng, Wanjoo; Kim, Hyungjun

2018-05-01

The improved electrical properties of Cu-gate thin-film transistors (TFTs) using an ink-synthesizing process were studied; this technology enables a low-cost and large area process for the display industry. We investigated the film properties and the effects of the ink-synthesized Cu layer in detail with respect to device characteristics. The mobility and reliability of the devices were significantly improved by applying a diffusion barrier at the interface between the Cu gate and the gate insulator. By using a TaN diffusion barrier layer, considerably improved and stabilized ink-Cu gated TFTs could be realized, comparable to sputtered-Cu gated TFTs under positive bias temperature stress measurements.
High-Performance Ink-Synthesized Cu-Gate Thin-Film Transistor with Diffusion Barrier Formation

Science.gov (United States)

Woo, Whang Je; Nam, Taewook; Oh, Il-Kwon; Maeng, Wanjoo; Kim, Hyungjun

2018-02-01

The improved electrical properties of Cu-gate thin-film transistors (TFTs) using an ink-synthesizing process were studied; this technology enables a low-cost and large area process for the display industry. We investigated the film properties and the effects of the ink-synthesized Cu layer in detail with respect to device characteristics. The mobility and reliability of the devices were significantly improved by applying a diffusion barrier at the interface between the Cu gate and the gate insulator. By using a TaN diffusion barrier layer, considerably improved and stabilized ink-Cu gated TFTs could be realized, comparable to sputtered-Cu gated TFTs under positive bias temperature stress measurements.
[Influence of Spectral Pre-Processing on PLS Quantitative Model of Detecting Cu in Navel Orange by LIBS].

Science.gov (United States)

Li, Wen-bing; Yao, Lin-tao; Liu, Mu-hua; Huang, Lin; Yao, Ming-yin; Chen, Tian-bing; He, Xiu-wen; Yang, Ping; Hu, Hui-qin; Nie, Jiang-hui

2015-05-01

Cu in navel orange was detected rapidly by laser-induced breakdown spectroscopy (LIBS) combined with partial least squares (PLS) for quantitative analysis, then the effect on the detection accuracy of the model with different spectral data ptetreatment methods was explored. Spectral data for the 52 Gannan navel orange samples were pretreated by different data smoothing, mean centralized and standard normal variable transform. Then 319~338 nm wavelength section containing characteristic spectral lines of Cu was selected to build PLS models, the main evaluation indexes of models such as regression coefficient (r), root mean square error of cross validation (RMSECV) and the root mean square error of prediction (RMSEP) were compared and analyzed. Three indicators of PLS model after 13 points smoothing and processing of the mean center were found reaching 0. 992 8, 3. 43 and 3. 4 respectively, the average relative error of prediction model is only 5. 55%, and in one word, the quality of calibration and prediction of this model are the best results. The results show that selecting the appropriate data pre-processing method, the prediction accuracy of PLS quantitative model of fruits and vegetables detected by LIBS can be improved effectively, providing a new method for fast and accurate detection of fruits and vegetables by LIBS.
Development of a hybrid sputtering/evaporation process for Cu(In,Ga)Se{sub 2} thin film solar cells

Energy Technology Data Exchange (ETDEWEB)

Acciarri, M.; Binetti, S.; Le Donne, A.; Lorenzi, B.; Caccamo, L.; Miglio, L. [Dipartimento di Scienza dei Materiali e Solar Energy Research Center MIB-SOLAR, Universita di Milano Bicocca, Milan (Italy); Moneta, R.; Marchionna, S.; Meschia, M. [Voltasolar s.r.l, Turate (Italy)

2011-08-15

In this paper we report a new method for Cu(In,Ga)Se{sub 2} deposition for solar cell application. Differently from the common co-evaporation process, an alterative approach for thin film Cu(In,Ga)Se{sub 2} has been tested: the sputtering deposition of metal elements combined with the selenium evaporation. We have studied the relationships between the growth parameters of our hybrid sputtering/evaporation method and the chemical-physical properties of the CIGS films. The cells are completed with a CdS buffer layer deposited by chemical bath deposition and ZnO + ITO deposited by RF sputtering. Test solar cells of 0.5 cm{sup 2} have shown an efficiency of 10% and 2.5% on glass and stainless steel substrate respectively. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
N-type Cu2O Film for Photocatalytic and Photoelectrocatalytic Processes: Its stability and Inactivation of E. coli

International Nuclear Information System (INIS)

Xiong, Liangbin; Ng, Tsz Wai; Yu, Ying; Xia, Dehua; Yip, Ho Yin; Li, Guiying; An, Taicheng; Zhao, Huijun; Wong, Po Keung

2015-01-01

Highlights: • Photoelectrocatalytic inactivation of E. coli by Cu 2 O film was firstly reported. • 7 log of E. coli could be completely inactivated in 2 h by Cu 2 O with a 0.1 V bias. • Charge transfer between Cu 2 O and E. coli was monitored by electrochemical technique. • Inactivation of E. coli by electric charges of electrodes was in-depth investigated. • Stability of N-type Cu 2 O as a photocatalyst was studied for the first time. - ABSTRACT: Photoelectrocatalytic (PEC) inactivation of Escherichia coli K-12 by cuprous oxide (Cu 2 O) film irradiated by visible light is firstly reported. A complete inactivation of about 7 log of E. coli was obtained for Cu 2 O film within 6 h. The bacterial inactivation efficiency was significantly improved in a photoelectrochemical cell, in which 7 log of E. coli could be completely inactivated within 2 h by Cu 2 O film with a 0.1 V bias. Electric charge transfer between electrodes and E. coli, and electric charge inactivation towards E. coli were investigated using membrane-separated reactor combined with short circuit photocurrent technique. H 2 O 2 , hole, and toxicity of Cu 2 O film were found responsible for the inactivation of E. coli. Toxicity of copper ions (including Cu 2+ and Cu + ) leakage from Cu 2 O films was determined and the results showed that the amount of leakage copper ions was not toxic to E. coli. Finally, the Cu 2 O film was proved to be effective and reusable for PC and PEC inactivation of E. coli
Ostwald ripening of decomposed phases in Cu-Ni-Cr alloys

International Nuclear Information System (INIS)

Hernandez-Santiago, Felipe; Lopez-Hirata, Victor; Dorantes-Rosales, Hector J.; Saucedo-Munoz, Maribel L.; Gonzalez-Velazquez, Jorge L.; Paniagua-Mercado, Ana Ma.

2008-01-01

A study of the coarsening process of the decomposed phases was carried out in the Cu-34 wt.% Ni-4 wt.% Cr and Cu-45 wt.% Ni-10 wt.% Cr alloys using transmission electron microscopy. As aging progressed, the morphology of the coherent decomposed Ni-rich phase changed from cuboids to platelets aligned in the Cu-rich matrix directions. Prolonged aging caused the loss of coherency between the decomposed phases and the morphology of the Ni-rich phase changed to ellipsoidal. The variation of mean radius of the coherent decomposed phases with aging time followed the modified LSW theory for thermally activated growth in ternary alloy systems. The linear variation of the density number of precipitates and matrix supersaturation with aging time, also confirmed that the coarsening process followed the modified LSW theory in both alloys. The coarsening rate was faster in the symmetrical Cu-45 wt.% Ni-10 wt.% Cr alloy due to its higher volume fraction of precipitates. The activation energy for thermally activated growth was determined to be about 182 and 102 kJ mol -1 in the Cu-34 wt.% Ni-4 wt.% Cr and Cu-45 wt.% Ni-10 wt.% Cr alloys, respectively. The lower energy for the former alloy seems to be related to an increase in the atomic diffusion process as the chromium content increases. The size distributions of precipitates in the Cu-Ni-Cr alloys were broader and more symmetric than that predicted by the modified LSW theory for ternary alloys
In-situ optical emission spectroscopy for a better control of hybrid sputtering/evaporation process for the deposition of Cu(In,Ga)Se{sub 2} layers

Energy Technology Data Exchange (ETDEWEB)

Posada, Jorge; Jubault, Marie [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF-CNRS-Chimie ParisTech, UMR 7174, 6 Quai Watier, 78401 Chatou (France); Bousquet, Angélique; Tomasella, Eric [Clermont Université, Université Blaise Pascal, Institute of Chemistry of Clermont-Ferrand (ICCF), CNRS-UMR 6296, 24 Avenue des Landais, 63171 Aubière (France); Lincot, Daniel [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF-CNRS-Chimie ParisTech, UMR 7174, 6 Quai Watier, 78401 Chatou (France)

2015-05-01

In this work, we have developed a hybrid one-step co-sputtering/evaporation Cu(In,Ga)Se{sub 2} (CIGS) process, where Cu, In and Ga are sputtered simultaneously with the thermal evaporation of selenium, thus avoiding the H{sub 2}Se use. An appropriate control of the selenium flux is very important to prevent the target poisoning and hence some material flux variations. Indeed, the control of the CIGS composition must be rigorous to ensure reproducible solar cell properties. In this regard, a study of the correlations between plasma species and thin film composition, structure and morphology has been performed by varying power values and Se evaporation temperature in the 170 to 230 °C range. We started by studying the plasma with a powerful technique: optical emission spectroscopy, following light emissions from different plasma species: sputtered Cu, Ga, In but also evaporated Se. Hence, we determined the Se flow threshold avoiding target poisoning and the main parameter controlling the CIGS composition. Obviously, we also focused our interest on the material. We measured film composition and thickness of the samples with X-ray fluorescence and by energy dispersive X-ray. Different phases formed during the process were identified by Raman spectroscopy and X-ray diffraction. The optoelectronic cell properties showed promising efficiency of 10.3% for an absorber with composition ratios of [Cu]/([In] + [Ga]) = 1.02 and [Ga]/([In] + [Ga]) = 0.44. Finally, this work shows that we are able to control this hybrid process and thus the structure and composition of CIGS thin film for industrial transfer in the photovoltaic field. - Highlights: • We have developed a hybrid one-step co-sputtering/evaporation Cu(In,Ga)Se{sub 2} process. • Correlations between plasma species and thin film composition have been performed. • We determined the Se flow threshold avoiding target poisoning. • Efficient small-area CIGS cells with 10.3% efficiency were fabricated.
Laser Trimming of CuAlMo Thin-Film Resistors: Effect of Laser Processing Parameters

Science.gov (United States)

Birkett, Martin; Penlington, Roger

2012-08-01

This paper reports the effect of varying laser trimming process parameters on the electrical performance of a novel CuAlMo thin-film resistor material. The films were prepared on Al2O3 substrates by direct-current (DC) magnetron sputtering, before being laser trimmed to target resistance value. The effect of varying key laser parameters of power, Q-rate, and bite size on the resistor stability and tolerance accuracy were systematically investigated. By reducing laser power and bite size and balancing this with Q-rate setting, significant improvements in resistor stability and resistor tolerance accuracies of less than ±0.5% were achieved.
N4H9Cu7S4: a hydrazinium-based salt with a layered Cu7S4- framework.

Science.gov (United States)

Mitzi, David B

2007-02-05

Crystals of a hydrazinium-based copper(I) sulfide salt, N4H9Cu7S4 (1), have been isolated by an ambient temperature solution-based process. In contrast to previously reported hydrazinium salts of main-group metal chalcogenides, which consist of isolated metal chalcogenide anions, and ACu7S4 (A = NH4+, Rb+, Tl+, K+), which contains a more three-dimensional Cu7S4- framework with partial Cu-site occupancy, the structure of 1 [P21, a = 6.8621(4) A, b = 7.9851(4) A, c = 10.0983(5) A, beta = 99.360(1) degrees , Z = 2] is composed of extended two-dimensional Cu7S4- slabs with full Cu-site occupancy. The Cu7S4- slabs are separated by a mixture of hydrazinium and hydrazine moieties. Thermal decomposition of 1 into copper(I) sulfide proceeds at a significantly lower temperature than that observed for analogous hydrazinium salts of previously considered metal chalcogenides, completing the transition at temperatures as low as 120 degrees C. Solutions of 1 may be used in the solution deposition of a range of Cu-containing chalcogenide films.
Mechanism insight of pollutant degradation and bromate inhibition by Fe-Cu-MCM-41 catalyzed ozonation.

Science.gov (United States)

Chen, Weirui; Li, Xukai; Tang, Yiming; Zhou, Jialu; Wu, Dan; Wu, Yin; Li, Laisheng

2018-03-15

A flexible catalyst, Fe-Cu-MCM-41, was employed to enhance diclofenac (DCF) mineralization and inhibit bromate formation in catalytic ozonation process. Greater TOC removal was achieved in Fe-Cu-MCM-41/O 3 process (78%) than those in Fe-MCM-41/O 3 (65%), Cu-MCM-41/O 3 (73%) and sole ozonation (42%). But it was interesting that both Cu-MCM-41/O 3 and Fe-MCM-41/O 3 achieved 93% bromate inhibition efficiency, only 71% inhibition efficiency was observed in Fe-Cu-MCM-41/O 3 . Influence of pH, TBA/NaHSO 3 and detection of by-products were conducted to explore the mechanism. By Pyridine adsorption-IR and XPS, a relationship was found among activity of catalysts, Lewis acid sites and electron transfer effect between Fe (II/III) and Cu (I/II). Fe-Cu-MCM-41 promoted ozone decomposition to generate OH, which accounted for enhanced DCF mineralization. The consumption of aqueous O 3 also suppressed the oxidative of Br - and HBrO/Br - . More HBrO/BrO - accumulated in catalytic ozonation process and less bromate generated. Bromate formation in Fe-Cu-MCM-41/O 3 process was sensitive with pH value, the acidic condition was not favor for bromate formation. Both DCF mineralization and bromate inhibition were influenced by surface reaction. Moreover, Fe-Cu-MCM-41 showed excellent catalytic performance in suppressing the accumulation of carboxylic acid, especially for oxalic acid. Nearly no oxalic acid was detected during Fe-Cu-MCM-41/O 3 process. Copyright © 2017 Elsevier B.V. All rights reserved.
Effects of calcium doping on the superconducting properties of top-seeded melt growth processed Y1.5Ba2-xCaxCu3Oy superconductors

International Nuclear Information System (INIS)

Park, S.D.; Kim, H.J.; Park, B.J.; Han, Y.H.; Jun, B.-H.; Lee, J.S.; Kim, C.-J.

2011-01-01

We study effects of calcium doping in melt processed Y123 superconductors. We examine a superconducting transition temperature and current density. A transition temperature and current density decreases by calcium doping. Calcium doping leads to coarseing of Y211 particles. Y211 refining effect by CeO 2 is disappreared by calcium doping. The effect of calcium doping on the superconducting properties of top seeded melt growth (TSMG) processed Y 1.5 Ba 2-x Ca x Cu 3 O y superconductors was studied in terms of calcium content (X ca ). YBa 2-x Ca x Cu 3 O 7-δ (X ca = 0, 0.005, 0.01, 0.02, 0.04, 0.1, 0.3) powders were synthesized by the powder calcination method. YBa 2-x Ca x Cu 3 O 7-δ powders were mixed with 0.25 mole Y 2 O 3 powder and 1 wt.% CeO 2 as Y 2 BaCuO 5 (Y211) refiner, and finally made into Y 1 . 5 Ba 2-x Ca x Cu 3 O y (Y1.5) + 1 wt.% CeO 2 composition. The single Y123 growth on the top surface was observed up to X ca = 0.1, while the multiple Y123 growth was observed at X ca ≥ 0.1. The superconducting transition temperature (T c ) and critical current density (J c ) of TSMG processed Y1.5 samples were inversely proportional to X ca . The Y211 size increased with increasing X ca due to the enhancement of Y211 coarsening by calcium doping. No Y211 refining effect by CeO 2 was observed in the calcium doped samples. The T c and J c decrease by calcium doping are likely to be due to the calcium incorporation with the Y123 lattice and formation of coarse Y211 particles.
Preparation and characterization of CuO nanowire arrays

International Nuclear Information System (INIS)

Yu Dongliang; Ge Chuannan; Du Youwei

2009-01-01

CuO nanowire arrays were prepared by oxidation of copper nanowires embedded in anodic aluminum oxide (AAO) membranes. The AAO was fabricated in an oxalic acid at a constant voltage. Copper nanowires were formed in the nanopores of the AAO membranes in an electrochemical deposition process. The oxidized copper nanowires at different temperatures were studied. X-ray diffraction patterns confirmed the formation of a CuO phase after calcining at 500 0 C in air for 30 h. A transmission electron microscopy was used to characterize the nanowire morphologies. Raman spectra were performed to study the CuO nanowire arrays. After measuring, we found that the current-voltage curve of the CuO nanowires is nonlinear.
Effect of preparation conditions on the properties of Cu3BiS3 thin films grown by a two - step process

Science.gov (United States)

Mesa, F.; Gordillo, G.

2009-05-01

Cu3BiS3 thin films were prepared on soda-lime glass substrates by co-evaporation of the precursors in a two-step process; for that, the metallic precursors were evaporated from a tungsten boat in presence of elemental sulfur evaporated from a tantalum effusion cell. The films were characterized by spectral transmittance, atomic force microscopy AFM and x-ray diffraction (XRD) measurements to investigate the effect of the growth conditions on the optical, morphological and structural properties. The results revealed that, independently of the deposition conditions, the films grow only in the orthorhombic Cu3BiS3 phase. It was also found that the Cu3BiS3 films present p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and an energy band gap Eg of about 1.41 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells.
Radiation enhanced copper clustering processes in Fe-Cu alloys during electron and ion irradiations as measured by electrical resistivity

International Nuclear Information System (INIS)

Ishino, S.; Chimi, Y.; Bagiyono; Tobita, T.; Ishikawa, N.; Suzuki, M.; Iwase, A.

2003-01-01

To study the mechanism of radiation-enhanced clustering of copper atoms in Fe-Cu alloys, in situ electrical resistivity measurements are performed during irradiation with 100 MeV carbon ions and with 2 MeV electrons at 300 K. Two kinds of highly pure Fe-Cu alloys with Cu content of 0.02 and 0.6 wt% are used. The results are summarized as follows: - Although there is a steep initial resistivity increase below about 10 μdpa, the resistivity steadily decreases after this initial transient in Fe-0.6wt%Cu alloy, while in Fe-0.02wt%Cu alloy, the resistivity either decreases slowly or stays almost constant. The rate of change in resistivity depends on copper concentration. - The rate of change in resistivity per dpa is larger for electron irradiation than for ion irradiation. - Change in dose rate from 10 -8 to 10 -9 dpa/s slightly enhances the rate of resistivity change per dpa. The decrease in resistivity with dose is considered to be due to clustering or precipitation of copper atoms. The initial abrupt increase in resistivity is too large to be accounted for by initial introduction of point defects before copper clustering. Tentatively the phenomenon is explained as due to the formation of embryos of copper precipitates with a large strain field around them. Quantitative evaluation of the results using resistivity contribution of a unit concentration of Frenkel pairs and that of copper atoms gives an important conclusion that more than one copper atom are removed from solid solution by one Frenkel pair. The clustering efficiency is surprisingly high in the present case compared with the ordinary radiation-induced or radiation-enhanced precipitation processes
Preparation of conductive Cu patterns by directly writing using nano-Cu ink

Energy Technology Data Exchange (ETDEWEB)

Li, Wei [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Li, Wenjiang; Wei, Jun [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Tan, Junjun [School of Chemical and Materials and Engineering, Hubei University of Technology, Hubei 435003 (China); Chen, Minfang, E-mail: mfchentj@126.com [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China)

2014-07-01

Conductive and air-stable Cu patterns were directly made on ordinary photo paper using a roller pen filled with nano-Cu ink, which was mainly composed of metallic Cu nanoparticles (NPs) capped with poly(N-vinylpyrrolidone) (PVP). The nano-Cu NPs were obtained via the reduction of Cu{sup 2+} ions by using an excess of hydrazine and PVP. The low sintering temperature (160 °C) in Ar atmosphere played an important role for the preparation of air-stable Cu patterns. The conductivity of a radio-frequency identification antenna made from nano-Cu ink was tested by a lamp, and its resistivity achieved 13.4 ± 0.4 μΩ cm. The Cu NPs were confirmed by means of X-ray powder diffraction and X-ray photoelectron spectra, and the Cu patterns were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. A mechanism for the high conductivity of the Cu pattern made from Cu NPs is proposed. - Highlights: • The synthesis of pure Cu is related to the reducing agent and capping agent. • The sintering under Ar atmosphere prevents Cu pattern's rapid oxidation. • The formation of the bulk Cu decreases the resistivity of the Cu pattern.
Cu/Cu{sub 2}O/CuO loaded on the carbon layer derived from novel precursors with amazing catalytic performance

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaoli, E-mail: zhaoxiaoli_zxl@126.com [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Tan, Yixin [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Wu, Fengchang, E-mail: wu_fengchang@126.com [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Niu, Hongyun [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Tang, Zhi [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Cai, Yaqi [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Giesy, John P. [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan (Canada)

2016-11-15

A simple, novel method for synthesis of Cu/Cu{sub 2}O/CuO on surfaces of carbon (Cu/Cu{sub 2}O/CuO@C) as a non-noble-metal catalyst for reduction of organic compounds is presented. Compared with noble metals, Cu/Cu{sub 2}O/CuO@C particles are more efficient and less expensive. Characterization of the Cu/Cu{sub 2}O/CuO@C composites by high-resolution transmission electron microscope (HRTEM), x-ray diffraction (XRD), infrared spectroscopy and Raman analysis, revealed that it was composed of graphitized carbon with numerous nanoparticles (100 nm in diameter) of Cu/CuO/Cu{sub 2}O that were uniformly distributed on internal and external surfaces of the carbon support. Gallic acid (GA) has been used as both organic ligand and carbon precursor with metal organic frameworks (MOFs) as the sacrificial template and metal oxide precursor in this green synthesis. The material combined the advantages of MOFs and Cu-containing materials, the porous structure provided a large contact area and channels for the pollutions, which results in more rapid catalytic degradation of pollutants and leads to greater efficiency of catalysis. The material gave excellent catalytic performance for organic dyes and phenols. In this study, Cu/Cu{sub 2}O/CuO@C was used as catalytic to reduce 4-NP, which has been usually adopted as a model reaction to check the catalytic ability. Catalytic experiment results show that 4-NP was degraded approximately 3 min by use of 0.04 mg of catalyst and the conversion of pollutants can reach more than 99%. The catalyst exhibited little change in efficacy after being utilized five times. Rates of degradation of dyes, such as Methylene blue (MB) and Rhodamine B (RhB) and phenolic compounds such as O-Nitrophenol (O-NP) and 2-Nitroaniline (2-NA) were all similar. - Highlights: • We present an effective catalyst for reductive degradation of organic dyes and phenols in water. • Compared with noble metals, Cu/Cu{sub 2}O/CuO@C particles are more efficient and less
Constitutive Model for Hot Deformation of the Cu-Zr-Ce Alloy

Science.gov (United States)

Zhang, Yi; Sun, Huili; Volinsky, Alex A.; Wang, Bingjie; Tian, Baohong; Liu, Yong; Song, Kexing

2018-02-01

Hot compressive deformation behavior of the Cu-Zr-Ce alloy has been investigated according to the hot deformation tests in the 550-900 °C temperature range and 0.001-10 s-1 strain rate range. Based on the true stress-true strain curves, the flow stress behavior of the Cu-Zr-Ce alloy was investigated. Microstructure evolution was observed by optical microscopy. Based on the experimental results, a constitutive equation, which reflects the relationships between the stress, strain, strain rate and temperature, has been established. Material constants n, α, Q and ln A were calculated as functions of strain. The equation predicting the flow stress combined with these materials constants has been proposed. The predicted stress is consistent with experimental stress, indicating that developed constitutive equation can adequately predict the flow stress of the Cu-Zr-Ce alloy. Dynamic recrystallization critical strain was determined using the work hardening rate method. According to the dynamic material model, the processing maps for the Cu-Zr and Cu-Zr-Ce alloy were obtained at 0.4 and 0.5 strain. Based on the processing maps and microstructure observations, the optimal processing parameters for the two alloys were determined, and it was found that the addition of Ce can promote the hot workability of the Cu-Zr alloy.
Structure and phase composition of Al-Ce-Cu system alloys in range of quasi-binary Al-Al8CeCu4 section

International Nuclear Information System (INIS)

Belov, N.A.; Khvan, A.V.

2007-01-01

The phase diagram of the Al-Cu-Ce system in the quasibinary section area of Al-Al 8 CeCu 4 has been investigated by metallographic, thermal, micro-X-ray spectral and X-ray structural analyses. The parameters of the eutectic reaction L→(Al)+CeCu 4 Al 8 : T=610 Deg C were found out; the composition was 14% Cu and 7% Ce. This eutectics is of a disperse structure and the ternary compound contained is capable of fragmentation and spheroidizing in the heating process (starting from 540 Deg C). It was demonstrated that the area of optimal (Al)+CeCu 4 Al 8 eutectics-based alloy compositions was within the narrow limits. That is related to the fact that at a comparatively little variation of the Cu:Ce=2 ratio solidus sharply decreases and, as a result, the crystallization interval considerably extends [ru
Quality analysis of the Al-Si-Cu alloy castings

Directory of Open Access Journals (Sweden)

L.A. Dobrzański

2007-04-01

Full Text Available The developed design methodologies both the material and technological ones will make it possible to improve shortly the quality of materials from the light alloys in the technological process, and the automatic process flow correction will make the production cost reduction possible, and - first of all - to reduce the amount of the waste products. Method was developed for analysis of the casting defects images obtained with the X-ray detector analysis of the elements made from the Al-Si-Cu alloys of the AC-AlSi7Cu3Mg type as well as the method for classification of casting defects using the artificial intelligence tools, including the neural networks; the developed method was implemented as software programs for quality control. Castings were analysed in the paper of car engine blocks and heads from the Al-Si-Cu alloys of the AC-AlSi7Cu3Mg type fabricated with the “Cosworth” technological process. The computer system, in which the artificial neural networks as well as the automatic image analysis methods were used makes automatic classification possible of defects occurring in castings from the Al-Si-Cu alloys, assisting and automating in this way the decisions about rejection of castings which do not meet the defined quality requirements, and therefore ensuring simultaneously the repeatability and objectivity of assessment of the metallurgical quality of these alloys.
Surface characterization of self-assembled N-Cu nanostructures

Energy Technology Data Exchange (ETDEWEB)

Cristina, Lucila J.; Moreno-Lopez, Juan C. [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Sferco, Silvano J. [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Departamento de Fisica, Facultad de Bioquimica y Ciencias Biologicas, Universidad Nacional del Litoral, Ciudad Universitaria, C.C. 242, (S3000ZAA) Santa Fe (Argentina); Passeggi, Mario C.G.; Vidal, Ricardo A. [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Ferron, Julio, E-mail: jferron@intec.unl.edu.ar [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Departamento de Materiales, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829,(S3000AOM) Santa Fe (Argentina)

2012-01-01

We report on the process of low energy N{sub 2}{sup +} implantation and annealing of a Cu(0 0 1) surface. Through AES we study the N diffusion process as a function of the substrate temperature. With STM and LEIS we characterize the surface morphology and the electronic structure is analyzed with ARUPS. Under annealing (500 < T < 700 K) N migrates to the surface and reacts forming a Cu{sub x}N compound that decomposes at temperatures above 700 K. LEIS measurements show that N locates on the four-fold hollow sites of the Cu(0 0 1) surface in a c(2 Multiplication-Sign 2) arrangement. Finally, a gap along the [0 0 1] azimuthal direction is determined by ARUPS. DFT calculations provide support to our conclusions.

A novel process for textured thick film YBa2Cu3Oy coated conductors based on a constitutional gradients principle

International Nuclear Information System (INIS)

Reddy, E Sudhakar; Tarka, M; Noudem, J G; Goodilin, E A; Schmitz, G J

2005-01-01

A new method for the processing of textured YBa 2 Cu 3 O y (Y 123) thick film stripes on metallic tapes is discussed. The process involves the texturing of Y123 grains by a localized directional solidification method by creating constitutional gradients along the width of the precursor Y 2 BaCuO 5 (Y 211) stripe during an infiltration and growth process. The differences in the solidification temperatures of different rare earth 123 compounds were utilized to generate the constitutional gradients. The sample configuration involves printed lines of light (Nd) and heavy (Yb) rare earth compounds on either side of an airbrushed Y211 stripe underneath a liquid phase (barium cuprates) layer. The higher peritectic temperature (T p ) Nd regions serve as nucleating sites for Y123 grains nucleated in the adjacent Y211 stripes and the constitutional gradients produced due to the diffusion of respective rare earth ions between the Nd and Yb regions, typically of 200 K cm -1 in the region, induce a driving force for the directional growth of the nucleated grains. The solidification is analogous to that in a typical Bridgman furnace in applied high temperature gradients. The process, being independent of growth rate parameter and texture of the underlying substrate, is suitable for the fabrication of long length thick film conductors by a wind and react process in simple box type furnaces
The crystal structure of (Nb$_{0.75}$Cu$_{0.25}$)Sn$_{2}$ in the Cu-Nb-Sn system

CERN Document Server

Martin, Stefan; Nolze, Gert; Leineweber, Andreas; Leaux, Floriane; Scheuerlein, Christian

2017-01-01

During the processing of superconducting Nb$_{3}$Sn wire, several intermediate intermetallic phases including a previously encountered Cu-Nb-Sn phase show up. The yet unknown crystal structure of this phase is now identified by a combination of different experimental techniques and database search to be of the hexagonal NiMg2 type with a proposed composition of about (Nb0.75Cu0.25)Sn2. The structure determination started from an evaluation of the lattice parameters from EBSD Kikuchi patterns from quenched material suggesting hexagonal or orthorhombic symmetry. A database search then led to the hexagonal NiMg2 type structure, the presence of which was confirmed by a Rietveld analysis on the basis of high energy synchrotron X-ray powder diffraction data. Assuming a partial substitution of Nb in orthorhombic NbSn2 by Cu, the change of the valence electron concentration provokes a structural transformation from the CuMg2 type for NbSn2 to the NiMg2 type for (Nb0.75Cu0.25)Sn2. In the previous literature the (Nb0.7...
The influence of post-processing on creep and microstructure of rolled Cu-8Cr-4Nb

Energy Technology Data Exchange (ETDEWEB)

Walley, J.L.; Heelan, J.L.; Vettraino, L.G.; Groza, J.R. [Department of Chemical Engineering and Materials Science, University of California, One Shields Ave., Davis, CA 95616 (United States); Gibeling, J.C., E-mail: jcgibeling@ucdavis.edu [Department of Chemical Engineering and Materials Science, University of California, One Shields Ave., Davis, CA 95616 (United States)

2010-10-15

Research highlights: {yields} A simulated-life heat treatment anneal of 24 h at 773 K reduced the steady-state creep rate and increased the creep life of a rolled powder metallurgy Cu-8Cr-4Nb alloy. {yields} The primary microstructural difference between the rolled form and the annealed form of Cu-8Cr-4Nb is the development of annealing twins during heat treatment causing a decrease in the intensity of the texture. {yields} Friction stir welding of rolled Cu-8Cr-4Nb negatively affected creep ductility, thereby decreasing creep life at the temperature tested. Strain localization in the soft heat-affected zone of the weld is hypothesized to be the cause of the decreased creep ductility. - Abstract: Previous work has shown that rolling of an extruded Cu-8Cr-4Nb (GRCop-84) alloy results in higher steady-state creep rates over a range of stresses, leading to concern that other post-processing methods could have substantial deleterious effects on creep properties. To explore that possibility, constant-stress creep tests were conducted at 773 K on rolled GRCop-84 after it was subjected to either friction stir welding (FSW) or a 24 h 1073 K simulated-life heat treatment. The FSW had no measurable effect on the creep rate of the rolled material, but did have detrimental effects on the creep ductility caused by softening, and thus strain localization, in the heat-affected zone of the weld. The simulated-life heat treatment decreased the steady-state creep rate by approximately 45% as compared to the rolled material, leading to longer creep life at a particular applied stress. Electron backscatter diffraction methods were used to compare the microstructural features of extruded, rolled and annealed material forms. It was determined that the rolling procedure decreased the grain size, and decreased the intensity of the texture as compared to the extruded form. The simulated-life heat treatment allowed for the substantial development of twins along with minor grain growth, and
The influence of post-processing on creep and microstructure of rolled Cu-8Cr-4Nb

International Nuclear Information System (INIS)

Walley, J.L.; Heelan, J.L.; Vettraino, L.G.; Groza, J.R.; Gibeling, J.C.

2010-01-01

Research highlights: → A simulated-life heat treatment anneal of 24 h at 773 K reduced the steady-state creep rate and increased the creep life of a rolled powder metallurgy Cu-8Cr-4Nb alloy. → The primary microstructural difference between the rolled form and the annealed form of Cu-8Cr-4Nb is the development of annealing twins during heat treatment causing a decrease in the intensity of the texture. → Friction stir welding of rolled Cu-8Cr-4Nb negatively affected creep ductility, thereby decreasing creep life at the temperature tested. Strain localization in the soft heat-affected zone of the weld is hypothesized to be the cause of the decreased creep ductility. - Abstract: Previous work has shown that rolling of an extruded Cu-8Cr-4Nb (GRCop-84) alloy results in higher steady-state creep rates over a range of stresses, leading to concern that other post-processing methods could have substantial deleterious effects on creep properties. To explore that possibility, constant-stress creep tests were conducted at 773 K on rolled GRCop-84 after it was subjected to either friction stir welding (FSW) or a 24 h 1073 K simulated-life heat treatment. The FSW had no measurable effect on the creep rate of the rolled material, but did have detrimental effects on the creep ductility caused by softening, and thus strain localization, in the heat-affected zone of the weld. The simulated-life heat treatment decreased the steady-state creep rate by approximately 45% as compared to the rolled material, leading to longer creep life at a particular applied stress. Electron backscatter diffraction methods were used to compare the microstructural features of extruded, rolled and annealed material forms. It was determined that the rolling procedure decreased the grain size, and decreased the intensity of the texture as compared to the extruded form. The simulated-life heat treatment allowed for the substantial development of twins along with minor grain growth, and a substantial
Cu-Doped ZnO Thin Films Deposited by a Sol-Gel Process Using Two Copper Precursors: Gas-Sensing Performance in a Propane Atmosphere

Directory of Open Access Journals (Sweden)

Heberto Gómez-Pozos

2016-01-01

Full Text Available A study on the propane gas-sensing properties of Cu-doped ZnO thin films is presented in this work. The films were deposited on glass substrates by sol-gel and dip coating methods, using zinc acetate as a zinc precursor, copper acetate and copper chloride as precursors for doping. For higher sensitivity values, two film thickness values are controlled by the six and eight dippings, whereas for doping, three dippings were used, irrespective of the Cu precursor. The film structure was analyzed by X-ray diffractometry, and the analysis of the surface morphology and film composition was made through scanning electron microscopy (SEM and secondary ion mass spectroscopy (SIMS, respectively. The sensing properties of Cu-doped ZnO thin films were then characterized in a propane atmosphere, C3H8, at different concentration levels and different operation temperatures of 100, 200 and 300 °C. Cu-doped ZnO films doped with copper chloride presented the highest sensitivity of approximately 6 × 104, confirming a strong dependence on the dopant precursor type. The results obtained in this work show that the use of Cu as a dopant in ZnO films processed by sol-gel produces excellent catalysts for sensing C3H8 gas.
Mechanical properties of Al-Cu alloy-SiC composites

Science.gov (United States)

Anggara, B. S.; Handoko, E.; Soegijono, B.

2014-09-01

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.
Mechanical properties of Al-Cu alloy-SiC composites

Energy Technology Data Exchange (ETDEWEB)

Anggara, B. S., E-mail: anggorobs1960@yahoo.com [Jurusan Fisika, FMIPA Universitas Negeri Jakarta, Indonesia 13220 and PPS Ilmu Material, Department Fisika, FMIPA, Universitas Indonesia (Indonesia); Handoko, E. [Jurusan Fisika, FMIPA Universitas Negeri Jakarta, 13220 (Indonesia); Soegijono, B. [PPS Ilmu Material, Department Fisika, FMIPA, Universitas Indonesia (Indonesia)

2014-09-25

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.
Effects of hydrazine on the solvothermal synthesis of Cu2ZnSnSe4 and Cu2CdSnSe4 nanocrystals for particle-based deposition of films

International Nuclear Information System (INIS)

Chiang, Ming-Hung; Fu, Yaw-Shyan; Shih, Cheng-Hung; Kuo, Chun-Cheng; Guo, Tzung-Fang; Lin, Wen-Tai

2013-01-01

The effects of hydrazine on the synthesis of Cu 2 ZnSnSe 4 (CZTSe) and Cu 2 CdSnSe 4 (CCTSe) nanocrystals in an autoclave as a function of temperature and time were explored. On heating at 190 °C for 24-72 h, pure CZTSe and CCTSe nanocrystals could readily grow in the hydrazine-added solution, while in the hydrazine-free solution the intermediate phases such as ZnSe, Cu 2 Se, and Cu 2 SnSe 3 , and Cu 2 SnSe 3 and CdSe associated with the CZTSe and CCTSe nanocrystals grew, respectively. This result reveals that hydrazine can speed up the synthesis of pure CZTSe and CCTSe nanocrystals via a solvothermal process. The mechanisms for the hydrazine-enhanced growth of CZTSe and CCTSe nanocrystals were discussed. The pure CZTSe and CCTSe nanocrystals were subsequently fabricated to the smooth films by spin coating without further annealing in selenium atmosphere. This processing may be beneficial to the fabrication of the absorber layer for solar cells and thermoelectric devices. - Highlights: • Hydrazine enhances the growth of pure Cu 2 ZnSnSe 4 and Cu 2 CdSnSe 4 nanocrystals. • The nanocrystals can be fabricated to films by spin coating without annealing. • This solvothermal processing is promising for the fabrication of thin film devices
Rapid formation of the 110 K phase in Bi-Pb-Sr-Ca-Cu-O through freeze-drying powder processing

International Nuclear Information System (INIS)

Song, K.H.; Liu, H.K.; Dou, S.X.; Sorrell, C.C.

1990-01-01

This paper reports three techniques for processing Bi-Pb-Sr-Ca-Cu-O (BPSCCO) powders investigated: dry-mixing, sol-gel formation, and freeze-drying. It was found that sintering for 120 h at 850 degrees C is required to form nearly single-phase (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10-y by dry-mixing, whereas sintering for 30 h at 840 degrees C was sufficient to form the 110 K (2223) phase when freeze-drying was used. The sol-gel route was found to be intermediate in efficiency between these two techniques. Freeze-drying provided highly reactive, intimately mixed, and carbon-free precursors. The presence of carbonates in the uncalcined powders was the major cause of phase segregation and sluggishness of the 110 K phase formation
Scalable production of Cu@C composites for cross-coupling catalysis

Energy Technology Data Exchange (ETDEWEB)

Bu, Lijuan [Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081 (China); Ming, Hai, E-mail: lunaticmh@163.com [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

2015-10-15

Highlights: • Cu@C core–shell composite was prepared by reduction of [Cu(NH{sub 3}){sub 4}]{sup 2+} with glucose. • The carbon shell in Cu@C can be tuned to the different degree of carbonization. • The Cu@C composites were utilized to catalyze the C−N cross coupling reaction. • The catalytic ability of Cu@C depends on the degree of shell-carbonization. - Abstract: A novel Cu@C core–shell microstructure was prepared by reduction of [Cu(NH{sub 3}){sub 4}]{sup 2+} with glucose using a mild hydrothermal process. The carbon shell of such Cu@C composite can be tuned to different carbonization degrees just through varying the calcination conditions. The structural properties of as-prepared Cu@C were investigated in detail by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron micrographs (TEM) and Raman spectra. In addition, these Cu@C composites were firstly used to catalyze the C−N cross coupling of amines with iodobenzene. Among them, the catalytic ability of Cu@C composites increased as their surface carbon’s carburization degree improved.
Cu-modified alkalinized g-C3N4 as photocatalytically assisted heterogeneous Fenton-like catalyst

Science.gov (United States)

Dong, Qimei; Chen, Yingying; Wang, Lingli; Ai, Shasha; Ding, Hanming

2017-12-01

Alkalinized graphitic carbon nitride (CNK-OH) has been synthesized by one-step thermal poly-condensation method, and Cu-modified alkalinized g-C3N4 (Cu-CNK-OH) has been prepared by impregnation approach over CNK-OH. These copper species in Cu-CNK-OH are embedded in the frame of CNK-OH mostly via the Cu-N bonds. Cu-CNK-OH has been employed as a heterogeneous Fenton-like catalyst to degrade rhodamine B (RhB). Both the production efficiency of hydroxyl radicals and the transformation rate of Cu(II)/Cu(I) redox pair increase under visible-light irradiation. As a result, Cu-CNK-OH exhibits improved Fenton-like catalytic activity on the degradation of RhB. The synergetic interaction between Fenton-like process and photocatalytic process also contributes such improvement. The hydroxyl radicals and holes are the major reactive species in the photocatalytically assisted Fenton-like process. This study provides a valuable strategy for metal modification of alkalinized g-C3N4 with enhanced Fenton-like catalytic performance for the degradation of organic contaminants.
Paleozoic–Mesozoic Porphyry Cu(Mo and Mo(Cu Deposits within the Southern Margin of the Siberian Craton: Geochemistry, Geochronology, and Petrogenesis (a Review

Directory of Open Access Journals (Sweden)

Anita N. Berzina

2016-11-01

Full Text Available The southern margin of the Siberian craton hosts numerous Cu(Mo and Mo(Cu porphyry deposits. This review provides the first comprehensive set of geological characteristics, geochronological data, petrochemistry, and Sr–Nd isotopic data of representative porphyry Cu(Mo and Mo(Cu deposits within the southern margin of the Siberian craton and discusses the igneous processes that controlled the evolution of these magmatic systems related to mineralization. Geochronological data show that these porphyry deposits have an eastward-younging trend evolving from the Early Paleozoic to Middle Mesozoic. The western part of the area (Altay-Sayan segment hosts porphyry Cu and Mo–Cu deposits that generally formed in the Early Paleozoic time, whereas porphyry Cu–Mo deposits in the central part (Northern Mongolia formed in the Late Paleozoic–Early Mesozoic. The geodynamic setting of the region during these mineralizing events is consistent with Early Paleozoic subduction of Paleo-Asian Ocean plate with the continuous accretion of oceanic components to the Siberian continent and Late Paleozoic–Early Mesozoic subduction of the west gulf of the Mongol–Okhotsk Ocean under the Siberian continent. The eastern part of the study area (Eastern Transbaikalia hosts molybdenum-dominated Mo and Mo–Cu porphyry deposits that formed in the Jurassic. The regional geodynamic setting during this mineralizing process is related to the collision of the Siberian and North China–Mongolia continents during the closure of the central part of the Mongol–Okhotsk Ocean in the Jurassic. Available isotopic data show that the magmas related to porphyritic Cu–Mo and Mo–Cu mineralization during the Early Paleozoic and Late Paleozoic–Early Mesozoic were mainly derived from mantle materials. The generation of fertile melts, related to porphyritic Mo and Mo–Cu mineralization during the Jurassic involved variable amounts of metasomatized mantle source component, the
Synthesis and characterization of YBaCu2O5-δ compound

Science.gov (United States)

Ehsandoust, A.; Sandoghchi, M.; Mokhtari, P.; Akhavan, M.

2018-05-01

YBaCu2O5 compound as one of the possible microstructures of Y3Ba5Cu8O19 has been synthesized. The X-ray diffraction analysis of this compound indicates that its formation is accompanied with the formation of YBa2Cu3O7-δ. The observed superconductivity around ∼92 K supports this. So, it seems that YBa2Cu3O7-δ is responsible for the observed superconductivity in YBaCu2O5, and this phase is not an independent superconducting phase. Consequently, the overall effect of the YBaCu2O5 formation during the Y3Ba5Cu8O19 fabrication process could be a reduction in Tc.
Pb, Cd, Cu and Zn biogeochemical behaviour and biological transfer processes in the Northwestern Mediterranean

International Nuclear Information System (INIS)

Nicolas, E.; Marty, J.C.; Miquel, J.C.; Fowler, S.W.

1999-01-01

Cd, Pb, Cu and Zn concentrations were determined in planktonic organisms (Salps, copepods), their associated faecal pellets and in particles collected at 200 and 2000 m depth in sediment traps moored in the Ligurian Sea. Al and P were also measured and taken as tracers of lithogenic and biogenic components, respectively. The aim of this work was to determine the fluxes of trace metals in the Ligurian Sea and their variations with depth, and to to assess the biogeochemical behaviour of elements having, for some of them, an anthropogenic origin, by the study of biologically-mediated uptake and removal processes
Proteomic response of mussels Mytilus galloprovincialis exposed to CuO NPs and Cu{sup 2+}: An exploratory biomarker discovery

Energy Technology Data Exchange (ETDEWEB)

Gomes, Tânia, E-mail: tania.gomes@niva.no; Chora, Suze; Pereira, Catarina G.; Cardoso, Cátia; Bebianno, Maria João

2014-10-15

Highlights: • Different protein expression patterns, tissue and Cu form dependent. • Different cellular mechanisms involved in CuO NPs and Cu{sup 2+} toxicity. • CuO NPs toxicity mediated by cell signalling cascades that result in apoptosis. • Caspase 3/7–1, catL, Zn-finger, precol-D as new molecular targets for both Cu forms in mussels. - Abstract: CuO NPs are one of the most used metal nanomaterials nowadays with several industrial and other commercial applications. Nevertheless, less is known about the mechanisms by which these NPs inflict toxicity in mussels and to what extent it differs from Cu{sup 2+}. The aim of this study was to investigate changes in protein expression profiles in mussels Mytilus galloprovincialis exposed for 15 days to CuO NPs and Cu{sup 2+} (10 μg L{sup −1}) using a proteomic approach. Results demonstrate that CuO NPs and Cu{sup 2+} induced major changes in protein expression in mussels’ showing several tissue and metal-dependent responses. CuO NPs showed a higher tendency to up-regulate proteins in the gills and down-regulate in the digestive gland, while Cu{sup 2+} showed the opposite tendency. Distinctive sets of differentially expressed proteins were found, either common or specific to each Cu form and tissue, reflecting different mechanisms involved in their toxicity. Fifteen of the differentially expressed proteins from both tissues were identified by MALDI-TOF-TOF. Identified proteins indicate common response mechanisms induced by CuO NPs and Cu{sup 2+}, namely in cytoskeleton and cell structure (actin, α-tubulin, paramyosin), stress response (heat shock cognate 71, putative C1q domain containing protein), transcription regulation (zinc-finger BED domain-containing protein 1, nuclear receptor subfamily 1G) and energy metabolism (ATP synthase F0 subunit 6). CuO NPs alone also had a marked effect on other biological processes, namely oxidative stress (GST), proteolysis (cathepsin L) and apoptosis (caspase 3/7-1). On
Effect of the existing form of Cu element on the mechanical properties, bio-corrosion and antibacterial properties of Ti-Cu alloys for biomedical application.

Science.gov (United States)

Zhang, Erlin; Wang, Xiaoyan; Chen, Mian; Hou, Bing

2016-12-01

Ti-Cu alloys have exhibited strong antibacterial ability, but Ti-Cu alloys prepared by different processes showed different antibacterial ability. In order to reveal the controlling mechanism, Ti-Cu alloys with different existing forms of Cu element were prepared in this paper. The effects of the Cu existing form on the microstructure, mechanical, corrosion and antibacterial properties of Ti-Cu alloys have been systematically investigated. Results have shown that the as-cast Ti-Cu alloys showed a higher hardness and mechanical strength as well as a higher antibacterial rate (51-64%) but a relatively lower corrosion resistance than pure titanium. Treatment at 900°C/2h (T4) significantly increased the hardness and the strength, improved the corrosion resistance but had little effect on the antibacterial property. Treatment at 900°C/2h+400°C/12h (T6) increased further the hardness and the mechanical strength, improved the corrosion resistance and but also enhanced the antibacterial rate (>90%) significantly. It was demonstrated that the Cu element in solid solution state showed high strengthening ability but low antibacterial property while Cu element in Ti2Cu phase exhibited strong strengthening ability and strong antibacterial property. Ti2Cu phase played a key role in the antibacterial mechanism. The antibacterial ability of Ti-Cu alloy was strongly proportional to the Cu content and the surface area of Ti2Cu phase. High Cu content and fine Ti2Cu phase would contribute to a high strength and a strong antibacterial ability. Copyright © 2016 Elsevier B.V. All rights reserved.
Stability of Cu-Precipitates in Al-Cu Alloys

Directory of Open Access Journals (Sweden)

Torsten E. M. Staab

2018-06-01

Full Text Available We present first principle calculations on formation and binding energies for Cu and Zn as solute atoms forming small clusters up to nine atoms in Al-Cu and Al-Zn alloys. We employ a density-functional approach implemented using projector-augmented waves and plane wave expansions. We find that some structures, in which Cu atoms are closely packed on {100}-planes, turn out to be extraordinary stable. We compare the results with existing numerical or experimental data when possible. We find that Cu atoms precipitating in the form of two-dimensional platelets on {100}-planes in the fcc aluminum are more stable than three-dimensional structures consisting of the same number of Cu-atoms. The preference turns out to be opposite for Zn in Al. Both observations are in agreement with experimental observations.
Comparison of Cu2+ and Zn2+ thermalcatalyst in treating diazo dye

Science.gov (United States)

Lau, Y. Y.; Wong, Y. S.; Ong, S. A.; Lutpi, N. A.; Ho, L. N.

2018-05-01

This research demonstrates the comparison between copper (II) sulphate (CuSO4) and zinc oxide (ZnO) as thermalcatalysts in thermolysis process for the treatment of diazo reactive black 5 (RB 5) wastewater. CuSO4 was found to be the most effective thermalcatalyst in comparison to ZnO. The color removal efficiency of RB 5 catalysed by CuSO4 and ZnO were 91.55 % at pH 9.5 and 7.36 % at pH 2, respectively. From the UV-Vis wavelength scan, CuSO4 catalyst is able to cleave the molecular structure bonding more efficiently compared to ZnO. ZnO which only show a slight decay on the main chemical network strands: azo bond, naphthalene and benzene rings whereas CuSO4 catalyst is able to fragment azo bond and naphthalene more effectively. The degradation reactions of CuSO4 and ZnO as thermalcatalysts in thermolysis process were compared.
Interactions between salt marsh plants and Cu nanoparticles - Effects on metal uptake and phytoremediation processes.

Science.gov (United States)

Andreotti, Federico; Mucha, Ana Paula; Caetano, Cátia; Rodrigues, Paula; Rocha Gomes, Carlos; Almeida, C Marisa R

2015-10-01

The increased use of metallic nanoparticles (NPs) raises the probability of finding NPs in the environment. A lot of information exists already regarding interactions between plants and metals, but information regarding interactions between metallic NPs and plants, including salt marsh plants, is still lacking. This work aimed to study interactions between CuO NPs and the salt marsh plants Halimione portulacoides and Phragmites australis. In addition, the potential of these plants for phytoremediation of Cu NPs was evaluated. Plants were exposed for 8 days to sediment elutriate solution doped either with CuO or with ionic Cu. Afterwards, total metal concentrations were determined in plant tissues. Both plants accumulated Cu in their roots, but this accumulation was 4 to 10 times lower when the metal was added in NP form. For P. australis, metal translocation occurred when the metal was added either in ionic or in NP form, but for H. portulacoides no metal translocation was observed when NPs were added to the medium. Therefore, interactions between plants and NPs differ with the plant species. These facts should be taken in consideration when applying these plants for phytoremediation of contaminated sediments in estuaries, as the environmental management of these very important ecological areas can be affected. Copyright © 2015 Elsevier Inc. All rights reserved.
Aging properties studies in a Cu-Ag-Cr Alloy

International Nuclear Information System (INIS)

Jia, S.G.; Zheng, M.S.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zhou, G.S.; Lou, H.F.

2006-01-01

A Cu-Ag-Cr alloy was produced by means of vacuum induction melting. The effects of aging processes on microhardness and conductivity of Cu-Ag-Cr alloy were studied. The microstructure of the alloy was examined using transmission electron microscope (TEM). Aging at 450 deg. C for 4 h, the alloy has an excellent combination of microhardness and conductivity, the microhardness and conductivity reach 132 HV and 80% IACS, respectively. The precipitates responsible for the age-hardening effect are fcc Cr. The fine and dispersed precipitates are fully coherent with the Cu matrix and make the Cu-Ag-Cr alloy possesses higher hardness and conductivity

The reaction process of the Bi-Sr-Ca-Cu-O system and the forming mechanism of the 2212 superconducting phase

International Nuclear Information System (INIS)

Xiong Guohong; Wang Minquan; Fan Xianping; Tang Xiaoming

1993-01-01

The reaction process and the reaction behavior of each component in the Bi-Sr-Ca-Cu-O system are presented in this paper. It reveals that the reaction is carried out in three different stages: forming of an insulating interphase at 680 C-790 C, forming of the 2212 superconducting phase at 790 C-860 C and forming of semiconducting phases in the presence of the liquid phase at 860 C-970 C. It is also confirmed that the 2212 superconducting phase (T c =85 K) is formed by the reaction of a trinary interphase together with CuO, SrO and CaO. A new two-step method is presented to prepare the 2212 superconducting phase by a presynthesized interphase. (orig.)
The reaction process of the Bi-Sr-Ca-Cu-O system and the forming mechanism of the 2212 superconducting phase

Science.gov (United States)

Xiong, Guohong; Wang, Minquan; Fan, Xianping; Tang, Xiaoming

1993-02-01

The reaction process and the reaction behavior of each component in the Bi-Sr-Ca-Cu-O system are presented in this paper. It reveals that the reaction is carried out in three different stages: forming of an insulating interphase at 680°C 790°C, forming of the 2212 superconducting phase at 790°C 860°C and forming often semiconducting phases in the presence of the liquid phase at 860°C 970°C. It is also confirmed that the 2212 superconducting phase ( T c=85 K) is formed by the reaction of a trinary interphase together with CuO, SrO and CaO. A new two-step method is presented to prepare the 2212 superconducting phase by a presynthesized interphase.
The reaction process of the Bi-Sr-Ca-Cu-O system and the forming mechanism of the 2212 superconducting phase

Energy Technology Data Exchange (ETDEWEB)

Xiong Guohong (Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering); Wang Minquan (Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering); Fan Xianping (Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering); Tang Xiaoming (Zhejiang Univ., Hangzhou (China). Center for Analysis and Measurement)

1993-02-01

The reaction process and the reaction behavior of each component in the Bi-Sr-Ca-Cu-O system are presented in this paper. It reveals that the reaction is carried out in three different stages: forming of an insulating interphase at 680 C-790 C, forming of the 2212 superconducting phase at 790 C-860 C and forming of semiconducting phases in the presence of the liquid phase at 860 C-970 C. It is also confirmed that the 2212 superconducting phase (T[sub c]=85 K) is formed by the reaction of a trinary interphase together with CuO, SrO and CaO. A new two-step method is presented to prepare the 2212 superconducting phase by a presynthesized interphase. (orig.)
Composition of Cu/Al system constructed by means of dynamic atomic deposition

International Nuclear Information System (INIS)

Tashlykov, I.S.; Tul'ev, V.V.

2011-01-01

Rutherford backscattering and RUMP simulation programme have been applied to investigate composition of Cu/Al system prepared using dynamic atomic deposition process when deposition of Cu thin film on Al substrate was assisted with 6 keV Ar + ions irradiation. It is estimated that thin ( ~15 nm) surface layer consists of ~50 at.% Cu, ~10 at.% Ar, ~4 at.% O and the remaining is Al. Dynamic deposition of Cu on Al substrate is accompanied with radiation enhanced diffusion of Cu, O, Ar atoms in substrate and out diffusion of Al atoms in deposited Cu coating. (authors)
High-purity Cu nanocrystal synthesis by a dynamic decomposition method

OpenAIRE

Jian, Xian; Cao, Yu; Chen, Guozhang; Wang, Chao; Tang, Hui; Yin, Liangjun; Luan, Chunhong; Liang, Yinglin; Jiang, Jing; Wu, Sixin; Zeng, Qing; Wang, Fei; Zhang, Chengui

2014-01-01

Cu nanocrystals are applied extensively in several fields, particularly in the microelectron, sensor, and catalysis. The catalytic behavior of Cu nanocrystals depends mainly on the structure and particle size. In this work, formation of high-purity Cu nanocrystals is studied using a common chemical vapor deposition precursor of cupric tartrate. This process is investigated through a combined experimental and computational approach. The decomposition kinetics is researched via differential sca...
Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles

Directory of Open Access Journals (Sweden)

Hyunjoon Song

2012-11-01

Full Text Available Recent developments in the synthesis of CuO nanoparticles (NPs and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.
Influence of Cu content on the cell biocompatibility of Ti–Cu sintered alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang, Erlin, E-mail: zhangel@atm.neu.edu.cn [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Jiamusi University, Jiamusi 154007 (China); Zheng, Lanlan [Jiamusi University, Jiamusi 154007 (China); Liu, Jie [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Dept. of Prosthodontics, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003 (China); Bai, Bing [Dept. of Prosthodontics, School of Stomatology, China Medical University, Liaoning Institute of Dental Research, Shenyang 110001 (China); Liu, Cong [Jiamusi University, Jiamusi 154007 (China)

2015-01-01

The cell toxicity and the cell function of Ti–Cu sintered alloys with different Cu contents (2, 5, 10 and 25 wt.%, respectively) have been investigated in comparison with commercial pure titanium in order to assess the influence of Cu content on the cell biocompatibility of the Ti–Cu alloys. The cytotoxicity was studied by examining the MG63 cell response by CCK8 assessment. The cell morphology was evaluated by acridine orange/ethidium bromide (AO/EB) fluorescence and observed under scanning electronic microscopy (SEM). The cell function was monitored by measuring the AKP activity. It has been shown by the AO/EB morphology results that the cell death on both cp-Ti sample and Ti–Cu samples is due to apoptosis rather than necrosis. Although more apoptotic cells were found on the Ti–2Cu and Ti–5Cu samples, no evidence of Cu content dependent manner of apoptosis has been found. SEM observation indicated very good cell adhesion and spread on the cp-Ti sample and the Ti–Cu samples with different Cu contents. CCK8 results displayed that increase in the Cu content in Ti–Cu alloys does not bring about any difference in the cell viability. In addition, AKP test results indicated that no difference in the differentiation of MG63 was found between the cp-Ti and the Ti–Cu samples and among the Ti–Cu samples. All results indicated that Ti–Cu alloys exhibit very good cell biocompatibility and the Cu content up to 25 wt.% in the Ti–Cu alloys has no influence on the cell proliferation and differentiation. - Highlights: • The effect of Cu content on the cell biocompatibility has been investigated. • Cu content shows no influence on the cell proliferation. • Cu content shows no effect on the cell differentiation.
Influence of Cu content on the cell biocompatibility of Ti–Cu sintered alloys

International Nuclear Information System (INIS)

Zhang, Erlin; Zheng, Lanlan; Liu, Jie; Bai, Bing; Liu, Cong

2015-01-01

The cell toxicity and the cell function of Ti–Cu sintered alloys with different Cu contents (2, 5, 10 and 25 wt.%, respectively) have been investigated in comparison with commercial pure titanium in order to assess the influence of Cu content on the cell biocompatibility of the Ti–Cu alloys. The cytotoxicity was studied by examining the MG63 cell response by CCK8 assessment. The cell morphology was evaluated by acridine orange/ethidium bromide (AO/EB) fluorescence and observed under scanning electronic microscopy (SEM). The cell function was monitored by measuring the AKP activity. It has been shown by the AO/EB morphology results that the cell death on both cp-Ti sample and Ti–Cu samples is due to apoptosis rather than necrosis. Although more apoptotic cells were found on the Ti–2Cu and Ti–5Cu samples, no evidence of Cu content dependent manner of apoptosis has been found. SEM observation indicated very good cell adhesion and spread on the cp-Ti sample and the Ti–Cu samples with different Cu contents. CCK8 results displayed that increase in the Cu content in Ti–Cu alloys does not bring about any difference in the cell viability. In addition, AKP test results indicated that no difference in the differentiation of MG63 was found between the cp-Ti and the Ti–Cu samples and among the Ti–Cu samples. All results indicated that Ti–Cu alloys exhibit very good cell biocompatibility and the Cu content up to 25 wt.% in the Ti–Cu alloys has no influence on the cell proliferation and differentiation. - Highlights: • The effect of Cu content on the cell biocompatibility has been investigated. • Cu content shows no influence on the cell proliferation. • Cu content shows no effect on the cell differentiation
Studies on Al-Cu-Li-Mg-Ag-Zr alloy processed through vacuum induction melting (VIM) technique

International Nuclear Information System (INIS)

Nayan, Niraj; Govind; Nair, K. Suseelan; Mittal, M.C.; Sudhakaran, K.N.

2007-01-01

A new technique of lithium addition has been adapted for the processing of Al-Cu-Li-Ag-Mg-Zr alloy, which gives more than 90% recovery of lithium throughout the billet. Processing studies on this alloy include casting, three step homogenization, to avoid incipient melting, and mechanical working particularly forging and rolling. The products in the form of sheets were subjected to various T6 (solution treatment + water quenching + aging) tempers. Mechanical properties were evaluated at room temperature and correlated with microstructure. Characterizations using optical microscope and post-fracture analysis have been carried out using Scanning electron microscope (SEM). Experimental investigation shows highest mechanical properties for the Al-1.3%Li alloy in T6 (500 deg. C/1 h + WQ + 190 deg. C/24 h) condition
Renal Cu and Na excretion and hepatic Cu metabolism in both Cu acclimated and non acclimated rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Grosell, M.; Hogstrand, C.; Wood, C.M.

1998-01-01

protein depending on whether the Cu is derived from recent branchial uptake or is already present in the plasma prior to Cu-64 exposure. The plasma Cu pool derived from recent branchial uptake and the Cu pool present in the plasma prior to Cu-64 exposure is accessible to renal excretion to different...... Na+ efflux decreased by 40%, which was largely due to increased tubular Na+ reabsorption. Renal compensation for the impaired branchial Na+ uptake, seen during Cu exposure, thus seems to be involved in Cu acclimation in rainbow trout. (C) 1998 Elsevier Science B.V....
Polarographic study of the Cu(II)/Cu(I) system in the presence of 1-ascorbic acid and 0,1 M ClK; Estudio polarografico del sistema Cu(II)/Cu(I) en presencia del acido 1-ascorbico y en ClK 0,1 M

Energy Technology Data Exchange (ETDEWEB)

Alonso Lopez, J

1969-07-01

While studying the catalytic effect of Cu{sup {down_arrow}}2 ions on the oxidation process of 1-ascorbic acid, it has been observed that, in a 0,1 M solution of K1 at a pH 6 to 7, the above acid gives rise in the presence of Cu{sup {down_arrow}}2 ions to a polarographic wave of half-wave potential of -0,41 V (vs. S.C.E.). (Author) 14 refs.
Consolidation processing parameters and alternative processing methods for powder metallurgy Al-Cu-Mg-X-X alloys

Science.gov (United States)

Sankaran, K. K.

1987-01-01

The effects of varying the vacuum degassing parameters on the microstructure and properties of Al-4Cu-1Mg-X-X (X-X = 1.5Li-0.2Zr or 1.5Fe-0.75Ce) alloys processed from either prealloyed (PA) or mechanically alloyed (M) powder, and consolidated by either using sealed aluminum containers or containerless vacuum hot pressing were studied. The consolidated billets were hot extruded to evaluate microstructure and properties. The MA Li-containing alloy did not include Zr, and the MA Fe- and Ce-containing alloy was made from both elemental and partially prealloyed powder. The alloys were vacuum degassed both above and below the solution heat treatment temperature. While vacuum degassing lowered the hydrogen content of these alloys, the range over which the vacuum degassing parameters were varied was not large enough to cause significant changes in degassing efficiency, and the observed variations in the mechanical properties of the heat treated alloys were attributed to varying contributions to strengthening by the sub-structure and the dispersoids. Mechanical alloying increased the strength over that of alloys of similar composition made from PA powder. The inferior properties in the transverse orientation, especially in the Li-containing alloys, suggested deficiencies in degassing. Among all of the alloys processed for this study, the Fe- and Ce-containing alloys made from MA powder possessed better combinations of strength and toughness.
High-temperature superconducting oxide synthesis and the chemical doping of the Cu-O planes

International Nuclear Information System (INIS)

Tarascon, J.M.; Barboux, P.; Bagley, B.G.; Greene, L.H.; McKinnon, W.R.; Hull, G.W.

1987-01-01

Different synthesis techniques for the preparation of dense superconducting ceramics are discussed, and a sol-gel process is shown to be very promising. The effect of oxygen content, and the effect of substitution of Ni and Zn for copper, on the structural, transport and superconducting properties of the La-Sr-Cu-O and Y-Ba-Cu-O systems are presented. The authors find that substitution on the copper sites destroys T/sub c/ in the La-Sr-Cu-O system and decreases it in the Y-Ba-Cu-O system, and this effect is insensitive as to whether the 3d metal is magnetic (Ni) or diamagnetic (Zn). A detailed study of the YBa/sub 2/Cu/sub 3/O/sub 7-y/ system as a function of oxygen content (y) shows that superconductivity can be destroyed in these materials by the removal of oxygen and restored by reinjecting oxygen; either thermally at 500 0 C or at temperatures (80 0 C) compatible with device processing by means of a novel plasma oxidation process. Of scientific interest, the plasma process induces bulk superconductivity in the undoped La/sub 2/CuO/sub 4/
Room-Temperature and Solution-Processable Cu-Doped Nickel Oxide Nanoparticles for Efficient Hole-Transport Layers of Flexible Large-Area Perovskite Solar Cells.

Science.gov (United States)

He, Qiqi; Yao, Kai; Wang, Xiaofeng; Xia, Xuefeng; Leng, Shifeng; Li, Fan

2017-12-06

Flexible perovskite solar cells (PSCs) using plastic substrates have become one of the most attractive points in the field of thin-film solar cells. Low-temperature and solution-processable nanoparticles (NPs) enable the fabrication of semiconductor thin films in a simple and low-cost approach to function as charge-selective layers in flexible PSCs. Here, we synthesized phase-pure p-type Cu-doped NiO x NPs with good electrical properties, which can be processed to smooth, pinhole-free, and efficient hole transport layers (HTLs) with large-area uniformity over a wide range of film thickness using a room-temperature solution-processing technique. Such a high-quality inorganic HTL allows for the fabrication of flexible PSCs with an active area >1 cm 2 , which have a power conversion efficiency over 15.01% without hysteresis. Moreover, the Cu/NiO x NP-based flexible devices also demonstrate excellent air stability and mechanical stability compared to their counterpart fabricated on the pristine NiO x films. This work will contribute to the evolution of upscaling flexible PSCs with a simple fabrication process and high device performances.
New production cross sections for the theranostic radionuclide 67Cu

Science.gov (United States)

Pupillo, Gaia; Sounalet, Thomas; Michel, Nathalie; Mou, Liliana; Esposito, Juan; Haddad, Férid

2018-01-01

The cross sections of the 68Zn(p,2p)67Cu, 68Zn(p,2n)67Ga and 68Zn(p,3n)66Ga reactions were measured at the ARRONAX facility by using the 70 MeV cyclotron, with particular attention to the production of the theranostic radionuclide 67Cu. Enriched 68Zn material was electroplated on silver backing and exposed to a low-intensity proton beam by using the stacked-foils target method. Since 67Cu and 67Ga radionuclides have similar half-lives and same γ-lines (they both decay to 67Zn), a radiochemical process aimed at Cu/Ga separation was mandatory to avoid interferences in γ-spectrometry measurements. A simple chemical procedure having a high separation efficiency (>99%) was developed and monitored during each foil processing, thanks to the tracer isotopes 61Cu and 66Ga. Nuclear cross sections were measured in the energy range 35-70 MeV by using reference reactions recommended by the International Atomic Energy Agency (IAEA) to monitor beam flux. In comparison with literature data a general good agreement on the trend of the nuclear reactions was noted, especially with latest measurements, but slightly lower values were obtained in case of 67Cu. Experimental results of the 68Zn(p,2p)67Cu, 68Zn(p,2n)67Ga and 68Zn(p,3n)66Ga reactions were also compared with the theoretical values estimated by using the software TALYS. The production yield of the theranostic radionuclide 67Cu was estimated considering the results obtained in this work.
Amorphous-to-Cu51Zr14 phase transformation in Cu60Ti20Zr20 alloy

International Nuclear Information System (INIS)

Cao, Q P; Zhou, Y H; Horsewell, A; Jiang, J Z

2003-01-01

The kinetics of an amorphous-to-Cu 51 Zr 14 phase transformation in an as-cast Cu 60 Ti 20 Zr 20 rod have been investigated by differential scanning calorimetry. The relative volume fractions of the transferred crystalline phase as a function of annealing time, obtained at 713, 716, 723, 728, and 733 K, have been analysed in detail using 14 nucleation and growth models together with the JMA model. A time-dependent nucleation process is revealed. A steady-state nucleation rate of the order of 10 22 - 10 23 nuclei m -3 s -1 in the temperature range 713-733 K and an activation energy of the order of 550 kJmol -1 for the phase transformation in the as-cast Cu 60 Ti 20 Zr 20 rod were detected, for which some possible reasons are suggested
Near-Infrared Emitting CuInSe2/CuInS2 Dot Core/Rod Shell Heteronanorods by Sequential Cation Exchange

Science.gov (United States)

2015-01-01

The direct synthesis of heteronanocrystals (HNCs) combining different ternary semiconductors is challenging and has not yet been successful. Here, we report a sequential topotactic cation exchange (CE) pathway that yields CuInSe2/CuInS2 dot core/rod shell nanorods with near-infrared luminescence. In our approach, the Cu+ extraction rate is coupled to the In3+ incorporation rate by the use of a stoichiometric trioctylphosphine-InCl3 complex, which fulfills the roles of both In-source and Cu-extracting agent. In this way, Cu+ ions can be extracted by trioctylphosphine ligands only when the In–P bond is broken. This results in readily available In3+ ions at the same surface site from which the Cu+ is extracted, making the process a direct place exchange reaction and shifting the overall energy balance in favor of the CE. Consequently, controlled cation exchange can occur even in large and anisotropic heterostructured nanocrystals with preservation of the size, shape, and heterostructuring of the template NCs into the product NCs. The cation exchange is self-limited, stopping when the ternary core/shell CuInSe2/CuInS2 composition is reached. The method is very versatile, successfully yielding a variety of luminescent CuInX2 (X = S, Se, and Te) quantum dots, nanorods, and HNCs, by using Cd-chalcogenide NCs and HNCs as templates. The approach reported here thus opens up routes toward materials with unprecedented properties, which would otherwise remain inaccessible. PMID:26449673
Cu-Zr-Ag bulk metallic glasses based on Cu8Zr5 icosahedron

International Nuclear Information System (INIS)

Xia Junhai; Qiang Jianbing; Wang Yingmin; Wang Qing; Dong Chuang

2007-01-01

Based on the cluster line criterion, the Ag addition into the Cu 8 Zr 5 cluster composition is investigated for the search of ternary Cu-Zr-Ag bulk metallic glasses with high glass forming abilities. Two initial binary compositions Cu 0.618 Zr 0.382 and Cu 0.64 Zr 0.36 are selected. The former one corresponds to a deep eutectic point; it is also the composition of the Cu 8 Zr 5 icosahedron, which is derived from the Cu 8 Zr 3 structure. The latter one, which can be regarded as the Cu 8 Zr 5 cluster plus a glue atom Cu, is the best glass-forming composition in the Cu-Zr binary system. Two composition lines (Cu 0.618 Zr 0.382 ) 1-x Ag x and (Cu 0.64 Zr 0.36 ) 1-x Ag x are thus constructed in the Cu-Zr-Ag system by linking these two compositions with the third constitute Ag. A series of Cu-Zr-Ag bulk metallic glasses are found with 2-8 at.% Ag contents in both composition lines. The optimum composition (Cu 0.618 Zr 0.382 ) 0.92 Ag 0.08 within the searched region with the highest T g /T l = 0.633, is located along the cluster line (Cu 0.618 Zr 0.382 ) 1-x Ag x , where the deep eutectic Cu 0.618 Zr 0.382 exactly corresponds to the dense packing cluster Cu 8 Zr 5 . The alloying mechanism is discussed in the light of atomic size and electron concentration factors
Stability enhancement of Cu2S against Cu vacancy formation by Ag alloying

Science.gov (United States)

Barman, Sajib K.; Huda, Muhammad N.

2018-04-01

As a potential solar absorber material, Cu2S has proved its importance in the field of renewable energy. However, almost all the known minerals of Cu2S suffer from spontaneous Cu vacancy formation in the structure. The Cu vacancy formation causes the structure to possess very high p-type doping that leads the material to behave as a degenerate semiconductor. This vacancy formation tendency is a major obstacle for this material in this regard. A relatively new predicted phase of Cu2S which has an acanthite-like structure was found to be preferable than the well-known low chalcocite Cu2S. However, the Cu-vacancy formation tendency in this phase remained similar. We have found that alloying silver with this structure can help to reduce Cu vacancy formation tendency without altering its electronic property. The band gap of silver alloyed structure is higher than pristine acanthite Cu2S. In addition, Cu diffusion in the structure can be reduced with Ag doped in Cu sites. In this study, a systematic approach is presented within the density functional theory framework to study Cu vacancy formation tendency and diffusion in silver alloyed acanthite Cu2S, and proposed a possible route to stabilize Cu2S against Cu vacancy formations by alloying it with Ag.
Characterization of p-CuI prepared by the SILAR technique on Cu-tape/n-CuInS2 for solar cells

International Nuclear Information System (INIS)

Sankapal, B.R.; Ennaoui, A.; Guminskaya, T.; Dittrich, Th.; Bohne, W.; Roehrich, J.; Strub, E.; Lux-Steiner, M.Ch.

2005-01-01

CuI has been synthesized at room temperature on Cu-tape/n-CuInS 2 by using the SILAR technique (successive ionic layer adsorption and reaction). The influence of wet chemical iodine treatment on the CuI has been investigated in more detail. The films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), elastic recoil detection analysis (ERDA) and surface photovoltage (SPV) techniques. The CuI films contain the no. gammano. -phase of the Zinkblende structure. The crystallites are preferentially oriented in the (111) direction. After wet chemical iodine treatment, the fibrous surface morphology changed to a more dense CuI film with larger crystallites. Oxides could not be detected on the CuI surface. The density of surface states of CIS decreased after the CuI deposition. The importance of the wet chemical iodine treatment for the performance of Cu-tape/n-CuInS 2 /p-CuI solar cells has been demonstrated

Cu diffusion as an alternative method for nanopatterned CuTCNQ film growth

International Nuclear Information System (INIS)

Capitán, M J; Álvarez, J; Miranda, R; Navío, C

2016-01-01

In this paper we show by means of ‘in situ’ x-ray diffraction studies that CuTCNQ formation from Cu(solid)–TCNQ(solid tetracyanoquinodimethane) goes through Cu diffusion at room temperature. The film quality depends on the TCNQ evaporation rate. At low evaporation rate we get a single phase-I CuTCNQ film very well crystallized and well oriented. The film has a CuTCNQ(0 2 0) orientation. The film is formed by CuTCNQ nanorods of a very homogeneous size. The film homogeneity has also been seen by atomic force microscopy (AFM). The electronic properties of the film have been measured by x-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). Thus, the Cu-diffusion method has arisen as a very simple, clean and efficient method to grow localized CuTCNQ nanorods on Cu, opening up new insights for technological applications. (paper)
Temperature dependence of the mechanical properties of melt-processed Dy-Ba-Cu-O bulk superconductors evaluated by three point bending tests

International Nuclear Information System (INIS)

Katagiri, K; Nyilas, A; Sato, T; Hatakeyama, Y; Hokari, T; Teshima, H; Iwamoto, A; Mito, T

2006-01-01

Dy-Ba-Cu-O bulk superconductor has an excellent capability of trapping magnetic flux and lower heat conductivity at cryogenic temperatures as compared with Y-Ba-Cu-O bulk superconductor. The Young's modulus and the bending strength in the range from room temperature to 7 K were measured by the three-point bending tests using specimens cut from a melt-processed Dy-Ba-Cu-O bulk superconductor. They were tested in a helium gas flow type cryostat at Forschungszentrum Karlsruhe and in a liquid nitrogen bath at Iwate University. The Young's modulus was calculated by either the slope of stress-strain curve or that of the load-deflection curve of the specimen. Although the bending strength measured in the two institutes coincided well, there was a significant discrepancy in the Young's modulus. The Young's modulus and bending strength increased with decrease of temperature down to 7 K. The amount of increase in the Young's modulus and the bending strength were about 32% and 36% of those at room temperature, respectively. The scatter of data for each run was significant and did not depend on temperature. The temperature dependence of the Young's modulus coincided with that in Y-Ba-Cu-O obtained by ultrasonic velocity. The temperature dependence of the Young's modulus and the bending strength was discussed from the view point of interatomic distance of the bulk crystal
Research progress in photolectric materials of CuFeS2

Science.gov (United States)

Jing, Mingxing; Li, Jing; Liu, Kegao

2018-03-01

CuFeS2 as a photoelectric material, there are many advantages, such as high optical absorption coefficient, direct gap semiconductor, thermal stability, no photo-recession effect and so on. Because of its low price, abundant reserves and non-toxic, CuFeS2 has attracted extensive attention of scientists.Preparation method of thin film solar cells are included that Electrodeposition, sputtering, thermal evaporation, thermal spraying method, co-reduction method.In this paper, the development of CuFeS2 thin films prepared by co-reduction method and co-reduction method is introduced.In this paper, the structure and development of solar cells, advantages of CuFeS2 as solar cell material, the structure and photoelectric properties and magnetic properties of CuFeS2, preparation process analysis of CuFeS2 thin film, research and development of CuFeS2 in solar cells is included herein. Finally, the development trend of CuFeS2 optoelectronic materials is analyzed and further research directions are proposed.
Analysis of controlled-mechanism of grain growth in undercooled Fe-Cu alloy

International Nuclear Information System (INIS)

Chen Zheng; Liu Feng; Yang Xiaoqin; Shen Chengjin; Fan Yu

2011-01-01

Highlights: → In terms of a thermo-kinetic model applicable for micro-scale undercooled Fe-4 at.% Cu alloy, grain growth behavior of the single-phase supersaturated granular grain was investigated. → In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, two characteristic annealing time were determined. → The controlled-mechanism of grain growth in undercooled Fe-Cu alloy was proposed, including a mainly kinetic-controlled process, a transition from kinetic-mechanism to thermodynamic-mechanism and purely thermodynamic-controlled process. - Abstract: An analysis of controlled-mechanism of grain growth in the undercooled Fe-4 at.% Cu immiscible alloy was presented. Grain growth behavior of the single-phase supersaturated granular grains prepared in Fe-Cu immiscible alloy melt was investigated by performing isothermal annealings at 500-800 deg. C. The thermo-kinetic model [Chen et al., Acta Mater. 57 (2009) 1466] applicable for nano-scale materials was extended to the system of micro-scale undercooled Fe-4 at.% Cu alloy. In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, two characteristic annealing time (t 1 and t 2 ) were determined. The controlled-mechanism of grain growth in undercooled Fe-Cu alloy was proposed, including a mainly kinetic-controlled process (t ≤ t 1 ), a transition from kinetic-mechanism to thermodynamic-mechanism (t 1 2 ) and purely thermodynamic-controlled process (t ≥ t 2 ).
Microstructure analysis of the automotive Al-Si-Cu castings

Directory of Open Access Journals (Sweden)

M. Krupiński

2008-04-01

Full Text Available The developed design methodologies both the material and technological ones will make it possible to improve shortly the quality of materials from the light alloys in the technological process, and the automatic process flow correction will make the production cost reduction possible, and - first of all - to reduce the amount of the waste products. In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters.Castings were analysed in the paper of car engine blocks and heads from the Al-Si-Cu alloys of the AC-AlSi7Cu3Mg type fabricated with the “Cosworth” technological process. In this work the AC-AlSi7Cu3Mg alloy structure was investigated, of this alloy samples were cut of for structure analysis of the cylinder part as well of crankshaft of a fuel engine. The investigation shows a difference in the (phase structure morphology as a result of cast cooling rate.
Cu(InGa)Se{sub 2} absorber formation by in-situ, low-temperature annealing of co-evaporated bilayer (InGa){sub 2}Se{sub 3}/CuSe precursors

Energy Technology Data Exchange (ETDEWEB)

Moon, Kyeongchan; Kim, Woo Kyoung, E-mail: wkim@ynu.ac.kr

2015-12-01

Chalcopyrite Cu(InGa)Se{sub 2} (CIGS) absorbers were fabricated by the formation of bilayer stacked glass/Mo/(InGa){sub 2}Se{sub 3}/CuSe precursors followed by in-situ thermal annealing at 450 °C for approximately 10 min in a vacuum evaporator. The material properties (e.g., crystal orientation, compositional depth profile, and overall composition) and device performance of the resulting CIGS absorbers were compared with those of the CIGS absorbers formed by conventional 1-stage and 3-stage CIGS formation processes at a similar temperature. X-ray diffraction confirmed that the 1-stage co-evaporation and in-situ annealing of the bilayer precursor produced a polycrystalline CIGS absorber without a specific texture, whereas the CIGS absorber formed by the 3-stage process showed a highly (220) preferred orientation. Secondary ion mass spectrometry revealed Ga accumulation at the bottom of CIGS formed by in-situ annealing of the bilayer precursors. The cell efficiency of the device with the CIGS absorber formed by the in-situ, low-temperature (450 °C) annealing of bilayer stacked glass/Mo/(InGa){sub 2}Se{sub 3}/CuSe precursors was comparable to that produced by the conventional 3-stage process at a similar temperature. - Highlights: • Annealing of (InGa){sub 2}Se{sub 3}/CuSe precursors was compared with coevaporation process. • In-situ annealing of (InGa){sub 2}Se{sub 3}/CuSe precursors at 450 °C produced about 9% solar cell. • Ga profile within Cu(InGa)Se{sub 2} depended on process profile during co-evaporation.
Molecular dynamics simulation of defect formation during energetic Cu deposition

International Nuclear Information System (INIS)

Gilmore, Charles M.; Sprague, James A.

2002-01-01

The deposition of energetic Cu atoms from 5 to 80 eV onto (0 0 1) Cu was simulated with molecular dynamics. The Cu-Cu interaction potential was a spline of the embedded atom potential developed from equilibrium data, and the universal scattering potential. Incident Cu atoms substituted for first layer substrate atoms by an exchange process at energies as low as 5 eV. Incident Cu atoms of 20 eV penetrated to the second substrate layer, and 20 eV was sufficient energy to produce interstitial defects. Incident atoms of 80 eV penetrated to the third atomic layer, produced interstitials 12 atomic layers into the substrate by focused replacement collision sequences, and produced sputtered atoms with a 16% yield. Interstitial clusters of up to 7 atoms were observed. The observed mechanisms of film growth included: the direct deposition of atoms into film equilibrium atom positions, the exchange of substrate atoms to equilibrium film atoms positions, and the migration of interstitials to equilibrium film atom positions. The relative frequency of each process was a function of incident energy. Since all observed growth mechanisms resulted in film atoms in equilibrium atomic positions, these simulations suggest that stresses in homoepitaxial Cu thin films are due to point defects. Vacancies would produce tensile strain and interstitial atoms would produce compressive strain in the films. It is proposed that immobile interstitial clusters could be responsible for retaining interstitial atoms and clusters in growing metal thin films
Effects of process variables on the properties of YBa2Cu3O(7-x) ceramics formed by investment casting

Science.gov (United States)

Hooker, M. W.; Taylor, T. D.; Leigh, H. D.; Wise, S. A.; Buckley, J. D.; Vasquez, P.; Buck, G. M.; Hicks, L. P.

1993-01-01

An investment casting process has been developed to produce net-shape, superconducting ceramics. In this work, a factorial experiment was performed to determine the critical process parameters for producing cast YBa2Cu3O7 ceramics with optimum properties. An analysis of variance procedure indicated that the key variables in casting superconductive ceramics are the particle size distribution and sintering temperature. Additionally, the interactions between the sintering temperature and the other process parameters (e.g., particle size distribution and the use of silver dopants) were also found to influence the density, porosity, and critical current density of the fired ceramics.
Growth and characterisation of potentiostatically electrodeposited Cu2O and Cu thin films

International Nuclear Information System (INIS)

Wijesundera, R.P.; Hidaka, M.; Koga, K.; Sakai, M.; Siripala, W.

2006-01-01

Cuprous oxide and copper thin films were potentiostatically electrodeposited in an acetate bath. Voltammetric curves were used to investigate the growth parameters; deposition potential, pH and temperature of the bath. Deposition potential dependency on the structural, morphological, optical and electronic properties of the films were investigated by the X-ray diffraction measurements, scanning electron micrographs, absorption measurements and dark and light current-voltage characterisations. It was observed that single phase polycrystalline Cu 2 O can be deposited from 0 to - 300 mV Vs saturated calomel electrode (SCE) and co-deposition of Cu and Cu 2 O starts at - 400 mV Vs SCE. Further increase in deposition potential from - 700 mV Vs SCE produces single phase Cu thin films. Single phase polycrystalline Cu 2 O thin films with cubic grains of 1-2 μm can be possible within the very narrow potential domain around - 200 mV Vs SCE. Enhanced photoresponse in a photoelectrochemical cell is produced by the Cu 2 O thin film prepared at - 400 mV Vs SCE, where Cu is co-deposited with Cu 2 O with random distribution of Cu spheres on the Cu 2 O surface. This study reveals that a single deposition bath can be used to deposit both Cu and Cu 2 O separately and an admixture of Cu-Cu 2 O by controlling the deposition parameters
Synthesis of Cu/Cu2O nanoparticles by laser ablation in deionized water and their annealing transformation into CuO nanoparticles

KAUST Repository

Gondal, M. A.; Qahtan, Talal F.; Dastageer, Mohamed Abdulkader; Maganda, Yasin W.; Anjum, Dalaver H.

2013-01-01

Nano-structured Cupric Oxide (CuO) has been synthesized using pulsed laser ablation of pure copper in water using Q-switched pulsed laser beam of 532 nm wavelength and, 5 nanosecond pulse duration and laser pulse energy of 100 mJ/pulse. In the initial unannealed colloidal suspension, the nanoparticles of Copper (Cu) and Cuprious oxide (Cu2O) were identified. Further the suspension was dried and annealed at different temperatures and we noticed the product (Cu/Cu2O) was converted predominantly into CuO at annealing temperature of 300 'C for 3 hours. As the annealing temperature was raised from 300 to 900 'C, the grain sizes of CuO reduced to the range of 9 to 26 nm. The structure and the morphology of the prepared samples were investigated using X-ray diffraction and Transmission Electron Microscope. Photoluminescence and UV absorption spectrometrystudies revealed that the band gap and other optical properties of nano-structured CuO were changed due to post annealing. Fourier transform spectrometry also confirmed the transformation of Cu/Cu2O into CuO. Copyright © 2013 American Scientific Publishers All rights reserved.
Synthesis of Cu/Cu2O nanoparticles by laser ablation in deionized water and their annealing transformation into CuO nanoparticles

KAUST Repository

Gondal, M. A.

2013-08-01

Nano-structured Cupric Oxide (CuO) has been synthesized using pulsed laser ablation of pure copper in water using Q-switched pulsed laser beam of 532 nm wavelength and, 5 nanosecond pulse duration and laser pulse energy of 100 mJ/pulse. In the initial unannealed colloidal suspension, the nanoparticles of Copper (Cu) and Cuprious oxide (Cu2O) were identified. Further the suspension was dried and annealed at different temperatures and we noticed the product (Cu/Cu2O) was converted predominantly into CuO at annealing temperature of 300 \\'C for 3 hours. As the annealing temperature was raised from 300 to 900 \\'C, the grain sizes of CuO reduced to the range of 9 to 26 nm. The structure and the morphology of the prepared samples were investigated using X-ray diffraction and Transmission Electron Microscope. Photoluminescence and UV absorption spectrometrystudies revealed that the band gap and other optical properties of nano-structured CuO were changed due to post annealing. Fourier transform spectrometry also confirmed the transformation of Cu/Cu2O into CuO. Copyright © 2013 American Scientific Publishers All rights reserved.
Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

Energy Technology Data Exchange (ETDEWEB)

Ho, Cheng-En, E-mail: ceho1975@hotmail.com; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien

2016-08-15

The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.
Solution processing of YBa2Cu3O7-x thin films

International Nuclear Information System (INIS)

Singhal, A.; Paranthaman, M.; Specht, E.D.; Hunt, R.D.; Beach, D.B.; Martin, P.M.; Lee, D.F.

1997-12-01

The aim of this work was to develop a non-vacuum chemical deposition technique for YBa 2 Cu 3 O 7-x (YBCO) coated conductors on rolling-assisted biaxially textured substrates (RABiTS). The authors have chosen the metal-organic decomposition (MOD) and sol-gel precursor routes to grow textured YBCO films. In the MOD process, yttrium 2-ethylhexonate, barium neodecanoate, copper 2-ethylhexonate and toluene were used as the starting reagents. YBCO films processed by the MOD method on SrTiO 3 (100) single crystal substrates were consisted of c and a-axis oriented materials. These films also contained some amount of the random phase. The c and a-axis oriented materials were epitaxial on SrTiO 3 substrates. Films have a T c,onset of 89K and the best superconducting transition temperature of 63K. Films pyrolyzed at 525 C and subsequently annealed at 780 C in a p(O 2 ) of 3.5 x 10 -4 atm contained YBCO phase predominantly in a-axis orientation. In the sol-gel route, yttrium-isopropoxide, barium metal, copper methoxide and 2-methoxyethanol were used as the starting reagents. Sol-gel YBCO films on SrTiO 3 substrates were epitaxial and c-axis oriented
Mechanical alloying in the Fe-Cu system

DEFF Research Database (Denmark)

Jiang, Jianzhong; Gente, C.; Bormann, R.

1998-01-01

The studies of mechanical alloying on the Fe-Cu system, as a model system for those with positive heats of mixing, are reviewed. Several problems involved in the mechanical alloying process are discussed. For example, (1) whether alloying occurs on an atomic level; (2) what the solid solubility...... in the Fe-Cu system is; (3) where the positive energy is stored in the alloys; (4) what the decomposition process of the supersaturated alloys is; and (5) what type of magnetic properties the new materials have. The elucidation of these problems will shed light on the understanding of the mechanisms...... for the preparation of materials under highly non-equilibrium conditions in systems with positive heats of mixing by mechanical alloying....
Surface Oxidation of the High-Strength Steels Electrodeposited with Cu or Fe and the Resultant Defect Formation in Their Coating during the Following Galvanizing and Galvannealing Processes

Science.gov (United States)

Choi, Yun-Il; Beom, Won-Jin; Park, Chan-Jin; Paik, Doojin; Hong, Moon-Hi

2010-12-01

This study examined the surface oxidation of high-strength steels electrodeposited with Cu or Fe and the resultant defect formation in their coating during the following galvanizing and galvannealing processes. The high-strength steels were coated with an Cu or Fe layer by the electroplating method. Then, the coated steels were annealed in a reducing atmosphere, dipped in a molten zinc, and finally transformed into galvannealed steels through the galvannealing process. The formation of Si and Mn oxides on the surface of the high-strength steel was effectively suppressed, and the density of surface defects on the galvanized steel was significantly reduced by the pre-electrodeposition of Cu and Fe. This effect was more prominent for the steels electrodeposited at higher cathodic current densities. The finer electrodeposit layer formed at higher cathodic current density on the steels enabled the suppression of partial surface oxidation by Mn or Si and better wetting of Zn on the surface of the steels in the following galvanizing process. Furthermore, the pre-electrodeposited steels exhibited a smoother surface without surface cracks after the galvannealing process compared with the untreated steel. The diffusion of Fe and Zn in the Zn coating layer in the pre-electrodeposited steels appears to occur more uniformly during the galvannealing process due to the low density of surface defects induced by oxides.
Synthesis of nanocrystalline Cu1-xTax composites using physical vapor deposition

International Nuclear Information System (INIS)

Savage, H.S.; Wang, H.; Rigsbee, J.M.

1993-01-01

Physical vapor deposition (PVD) processes provide the capability for creating new types of metallic, ceramic, and polymeric composites by allowing atomic-scale engineering of structure and chemistry. Because PVD processes provide the capacity for circumventing thermodynamic factors, such as solubility limits, it is possible to produce nonequilibrium alloys and materials with unique mixtures of phases. The ease by which PVD produces materials with nanocrystalline microstructures is an added benefit of these processes. This paper describes ion plating, a plasma-assisted PVD process, and its application for the development of a new class of nanoscale dispersion-strengthened Cu 1-x Ta x alloys. Copper-tantalum was selected as a model system because the extensive liquid miscibility gap and nearly zero mutual solid solubilities prevent creation of Cu-Ta alloys by conventional or rapid solidification processes. Microchemical analyses of the family of Cu 1-x Ta x alloys indicate that PVD can produce materials with any desired level of Ta. X-ray diffraction and transmission electron microscopy analyses show that the as-deposited microstructures consist generally of a Cu matrix supersaturated with Ta and containing a uniform dispersion of Ta particles with diameters below 10 nm. The Ta particles are face centered cubic (exceptionally large Ta particles, larger than ∼100 nm, are body centered cubic) and are oriented identically with the Cu matrix. Particle coarsening studies, at temperatures up to 900C and for times as long as 100 hours, indicate an extreme degree of microstructural stability. The Ta particles also appear highly effective at maintaining a submicron Cu matrix grain size even after annealing at 900C
Mechanical and microstructural properties of Cu-Al-Ni-Mn-Zr shape memory alloy processed by spray forming

Energy Technology Data Exchange (ETDEWEB)

Cava, R.D.; Bolfarini, C.; Kiminami, C.S.; Mazzer, E.M.; Pedrosa, V.M.; Botta, W.J.; Gargarella, P. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

2016-07-01

Full text: Cu-based shape memory alloys (SMA) presents higher thermal and electrical conductivities, low material cost and combine good mechanical properties with a pronounced shape memory effect [1]. By using rapid solidification methods, their microstructure is refined and detrimental segregations can be avoided, which results in better mechanical properties. Additionally, the microalloying additions as Ti, B, Si and Zr can refine the grains and improve of mechanical and thermal properties of Cu-based SMA alloys [2-4]. In this investigation the Cu81.95Al11.35Ni3.2Mn3Zr0.5 (wt%) SMA alloy has been processed by spray forming in order to investigate the potential of achieving a deposit with adequate microstructure with goal to a SMA part production. The alloy was atomized with nitrogen gas at pressure of 0.5MPa. The microstructure of the deposit was characterized by optical and scanning electron microscopy and X-ray diffraction. The deposit presented homogeneous microstructure consisting of equiaxial grains with martensite microstructure and mean grain size of 30 ?m. The shape memory effect and the temperatures transformation have been evaluated by differential scanning calorimetric. The mechanical properties were evaluated by tensile and compression tests at room and at 220 deg C(T>Af) temperatures. [1] T. Waitz, et al., T, J. of the Mechanics and Physics of Solids, 55, 2007. [2] D. W. Roh, et al., Metall Trans. A, 21, 1990. [3] D. W. Roh, et al., Mat. Sci. and Eng. A136, 1991. (author)
The Effect of Surfactant Content over Cu-Ni Coatings Electroplated by the sc-CO₂ Technique.

Science.gov (United States)

Chuang, Ho-Chiao; Sánchez, Jorge; Cheng, Hsiang-Yun

2017-04-19

Co-plating of Cu-Ni coatings by supercritical CO₂ (sc-CO₂) and conventional electroplating processes was studied in this work. 1,4-butynediol was chosen as the surfactant and the effects of adjusting the surfactant content were described. Although the sc-CO₂ process displayed lower current efficiency, it effectively removed excess hydrogen that causes defects on the coating surface, refined grain size, reduced surface roughness, and increased electrochemical resistance. Surface roughness of coatings fabricated by the sc-CO₂ process was reduced by an average of 10%, and a maximum of 55%, compared to conventional process at different fabrication parameters. Cu-Ni coatings produced by the sc-CO₂ process displayed increased corrosion potential of ~0.05 V over Cu-Ni coatings produced by the conventional process, and 0.175 V over pure Cu coatings produced by the conventional process. For coatings ~10 µm thick, internal stress developed from the sc-CO₂ process were ~20 MPa lower than conventional process. Finally, the preferred crystal orientation of the fabricated coatings remained in the (111) direction regardless of the process used or surfactant content.
Effect of 67Cu and 99Mo labeled tetrathiomolybdate on the distribution of 67Cu, Cu, and 99Mo in bile fractions in sheep

International Nuclear Information System (INIS)

Gooneratne, R.; Laarveld, B.; Christensen, D.

1989-01-01

The effect of intravenous administration of 67 Cu and 99 Mo labeled tetrathiomolybdate (TTM) on the appearance of 67 Cu, stable Cu, and 99 Mo in gel chromatographic fractions of bile was examined in sheep fed either 5 or 35 mg Cu kg-1 DM. Peak excretory periods of biliary 67 Cu, stable Cu, and 99 Mo were observed at 30 min-1.25 hr, 2-3 hr, and 11-13 hr after 67 Cu and after 99 Mo labeled TTM. Sephadex G-75 gel filtration of bile samples collected at 1, 3, and 12 hr after 67 Cu administration revealed two major protein peaks of molecular weights of greater than 80,000 (peak I) and 7,000 (peak II) containing both 67 Cu and Cu. But the ratio of 67 Cu in the two peaks varied with time of bile collection. The ratio of areas of peak I:II 1 hr after 67 Cu administration was approximately 0.48; at 3 hr, 0.62, and at 12 hr 1.35. Tetrathiomolybdate administration increased both 67 Cu and stable Cu in bile by severalfold and induced a major shift of Cu into the higher molecular weight protein fraction. The experiments confirm the effectiveness of TTM as a ''decoppering'' agent. Furthermore, TTM not only promoted bile Cu excretion, but it also increased the incorporation of Cu into the macromolecular fraction. This may limit enterohepatic circulation of biliary Cu and thereby cause an overall Cu depletion and a negative Cu balance
Solidified structure of Al-Pb-Cu alloys

International Nuclear Information System (INIS)

Ikeda, Tetsuyuki; Nishi, Seiki; Kumeuchi, Hiroyuki; Tatsuta, Yoshinori.

1986-01-01

Al-Pb-Cu alloys were cast into bars or plates in different two metal mold casting processes in order to suppress gravity segregation of Pb and to achieve homogeneous dispersion of Pb phase in the alloys. Solidified structures were analyzed by a video-pattern-analyzer. Plate castings 15 to 20 mm in thickness of Al-Pb-1 % Cu alloy containing Pb up to 5 % in which Pb phase particles up to 10 μm disperse are achieved through water cooled metal mold casting. The plates up to 5 mm in thickness containing Pb as much as 8 to 10 % cast in this process have dispersed Pb particles up to 5 μm in diameter in the surface layer. Al-8 % Pb-1 % Cu alloy bars 40 mm in diameter and 180 mm in height in which gravity segregation of Pb is prevented can be cast by movable and water sprayed metal mold casting at casting temperature 920 deg C and mold moving speed 1.0 mm/s. Pb phase particles 10 μm in mean size are dispersed in the bars. (author)

The effects of microalloying with Cd on precipitation processes in Al-1.7 Cu-0.3 mg (At. %) alloys

International Nuclear Information System (INIS)

Sofyan, Bondan T.

2002-01-01

The present work investigates the effects of microalloying with Cd on precipitation processes in Al-1.7 Cu-0.3 mg (At. %) alloys. Analytical STEM (Scanning Transmission Electron Microscope) revealed the presence of clusters rich in Cd and Mg at early stages of ageing, which is believed to be responsible in promoting the nucleation of θ (Al,Cu) in the alloy on its (001) planes. The Cd-Mg clusters then grow as Cd-Mg-rich particles when ageing is continued beyond the peak hardness. The presence of Cd-Mg-rich clusters is thought to play an important role on the nucleation of θ phase by accommodating the misfit strain on the non-coherent rim of the phase. The accommodation of misfit strain is made available by the presence of large amount of vacancies, which is trapped by Cd and Mg atoms during quenching, around θ platelet nuclei
Effect of processing of mechanical alloying and powder metallurgy on microstructure and properties of Cu-Al-Ni-Mn alloy

International Nuclear Information System (INIS)

Xiao Zhu; Li Zhou; Fang Mei; Xiong Shiyun; Sheng Xiaofei; Zhou Mengqi

2008-01-01

The fabrication conditions of Cu-Al-Ni-Mn alloy powder by mechanical alloying and powder metallurgy have been systematically studied. The mechanically alloyed powder (MAed powder) was fabricated at a speed between 100 rpm and 300 rpm for various milling times with and without process control agent (PCA). With an increasing of milling time, the size of crystallite grain decreases. Only the Cu diffraction pattern appear as the rotation speed is up to 300 rpm for 25 h. The elemental powders with PCA agglomerate slightly, but the degree of alloying is lower than that without PCA. The shape memory recovery of the quenched sample hot-extruded at extrusion rate of 50:1 is measured to be 100% recovered in 250 deg. C oil bath for 40 s after deformed to 4.0%. After aging at 120 deg. C for 10 days, the shape memory recovery of the alloy remains 98%
In-situ XRD study of alloyed Cu2ZnSnSe4-CuInSe2 thin films for solar cells

International Nuclear Information System (INIS)

Hartnauer, Stefan; Wägele, Leonard A.; Jarzembowski, Enrico; Scheer, Roland

2015-01-01

We investigate the growth of Cu 2 ZnSnSe 4 -CuInSe 2 (CZTISe) thin films using a 2-stage (Cu-rich/Cu-free) co-evaporation process under simultaneous application of in-situ angle dispersive X-ray diffraction (XRD). In-situ XRD allows monitoring the phase formation during preparation. A variation of the content of indium in CZTISe leads to a change in the lattice constant. Single phase CZTISe is formed in a wide range, while at high In contents a phase separation is detected. Because of different thermal expansion coefficients, the X-ray diffraction peaks of ZnSe and CZTISe can be distinguished at elevated substrate temperatures. The formation of ZnSe appears to be inhibited even for low indium content. In-situ XRD shows no detectable sign for the formation of ZnSe. First solar cells of CZTISe have been prepared and show comparable performance to CZTSe. - Highlights: • In-situ XRD study of two-stage co-evaporated Cu 2 ZnSnSe 4 -CuInSe 2 alloyed thin films. • No detection of ZnSe with in-situ XRD due to Indium incorporation • Comparable efficiency of alloyed solar cells
CuInSe2 nano-crystallite reaction kinetics using solid state reaction from Cu2Se and In2Se3 powders

International Nuclear Information System (INIS)

Hsiang, Hsing-I; Lu, Li-Hsin; Chang, Yu-Lun; Ray, Dahtong; Yen, Fu-Su

2011-01-01

Highlights: → CuInSe 2 phase increased gradually accompanied with a decrease in γ-In 2 Se 3 and no intermediate phase during calcination. → CuInSe 2 formation from Cu 2 Se and In 2 Se 3 powders follows a one-dimensional diffusion-controlled reaction with apparent activation energy of about 122.5 kJ/mol. → The solid reaction kinetics may be dominated by the diffusion of In 3+ ions. - Abstract: The reaction mechanism and CuInSe 2 formation kinetics using a solid state reaction from Cu 2 Se and In 2 Se 3 powders synthesized using a heating up process were investigated using X-ray diffractomy (XRD) and transmission electron microscopy (TEM). It was observed that the CuInSe 2 phase increased gradually, accompanied with a decrease in γ-In 2 Se 3 with no intermediate phase as the calcination temperature and soaking time were increased. The reaction kinetics was analyzed using the Avrami and polynomial kinetic model, suggesting that CuInSe 2 formation from Cu 2 Se and In 2 Se 3 powders follows a diffusion-controlled reaction with an apparent activation energy of about 122.5-182.3 kJ/mol. Cu 2 Se and In 2 Se 3 phases react and directly transform into CIS without the occurrence of any intermediate phase and the size of the newly formed CuInSe 2 crystallites was close to that of the Cu 2 Se reactant particle based on the TEM results, which indicated that the solid reaction kinetics may be dominated by the diffusion of In 3+ ions.
Characterization of Cu-exchanged SSZ-13: a comparative FTIR, UV-Vis, and EPR study with Cu-ZSM-5 and Cu-β with similar Si/Al and Cu/Al ratios

DEFF Research Database (Denmark)

Giordanino, Filippo; Vennestrøm, Peter N. R.; Lundegaard, Lars Fahl

2013-01-01

concentration of reduced copper centres, i.e. isolated Cu+ ions located in different environments, able to form Cu+(N2), Cu+(CO)n (n = 1, 2, 3), and Cu+(NO)n (n = 1, 2) upon interaction with N2, CO and NO probe molecules, respectively. Low temperature FTIR, DRUV-Vis and EPR analysis on O2 activated samples...... an intense and finely structured d–d quadruplet, unique to Cu-SSZ-13, which is persistent under SCR conditions. This differs from the 22 700 cm−1 band of the mono(μ-oxo)dicopper species of the O2 activated Cu-ZSM-5, which disappears under SCR conditions. The EPR signal intensity sets Cu-β apart from...
Characterization of p-CuI prepared by the SILAR technique on Cu-tape/n-CuInS{sub 2} for solar cells

Energy Technology Data Exchange (ETDEWEB)

Sankapal, B.R. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany)]. E-mail: brsankapal@rediffmail.com; Ennaoui, A. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Guminskaya, T. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Dittrich, Th. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Bohne, W. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Roehrich, J. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Strub, E. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Lux-Steiner, M.Ch. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany)

2005-06-01

CuI has been synthesized at room temperature on Cu-tape/n-CuInS{sub 2} by using the SILAR technique (successive ionic layer adsorption and reaction). The influence of wet chemical iodine treatment on the CuI has been investigated in more detail. The films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), elastic recoil detection analysis (ERDA) and surface photovoltage (SPV) techniques. The CuI films contain the no. gammano. -phase of the Zinkblende structure. The crystallites are preferentially oriented in the (111) direction. After wet chemical iodine treatment, the fibrous surface morphology changed to a more dense CuI film with larger crystallites. Oxides could not be detected on the CuI surface. The density of surface states of CIS decreased after the CuI deposition. The importance of the wet chemical iodine treatment for the performance of Cu-tape/n-CuInS{sub 2}/p-CuI solar cells has been demonstrated.
Ultraviolet emission from low resistance Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires

Directory of Open Access Journals (Sweden)

E. Karageorgou

2014-11-01

Full Text Available SnO2 and Sn:In2O3 nanowires were grown on Si(001, and p-n junctions were fabricated in contact with p-type Cu2S which exhibited rectifying current–voltage characteristics. Core-shell Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires were obtained by depositing copper and post-growth processing under H2S between 100 and 500 °C. These consist mainly of tetragonal rutile SnO2 and cubic bixbyite In2O3. We observe photoluminescence at 3.65 eV corresponding to band edge emission from SnO2 quantum dots in the Cu2SnS3/SnO2 nanowires due to electrostatic confinement. The Cu2SnS3/SnO2 nanowires assemblies had resistances of 100 Ω similar to CuInS2/In2O3 nanowires which exhibited photoluminescence at 3.0 eV.
Direct Observation of Reduction of Cu(II) to Cu(I) by Terminal Alkynes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Guanghui; Yi, Hong; Zhang, Guoting; Deng, Yi; Bai, Ruopeng; Zhang, Heng; Miller, Jeffrey T.; Kropf, Arthur J.; Bunel, Emilio E.; Lei, Aiwen

2014-01-06

ABSTRACT: X-ray absorption spectroscopy and in situ electron paramagnetic resonance evidence were provided for the reduction of Cu(II) to Cu(I) species by alkynes in the presence of tetramethylethylenediamine (TMEDA), in which TMEDA plays dual roles as both ligand and base. The structures of the starting Cu(II) species and the obtained Cu(I) species were determined as (TMEDA)- CuCl2 and [(TMEDA)CuCl]2 dimer, respectively.
New Production Routes for Medical Isotopes 64Cu and 67Cu Using Accelerator Neutrons

Science.gov (United States)

Kin, Tadahiro; Nagai, Yasuki; Iwamoto, Nobuyuki; Minato, Futoshi; Iwamoto, Osamu; Hatsukawa, Yuichi; Segawa, Mariko; Harada, Hideo; Konno, Chikara; Ochiai, Kentaro; Takakura, Kosuke

2013-03-01

We have measured the activation cross sections producing 64Cu and 67Cu, promising medical radioisotopes for molecular imaging and radioimmunotherapy, by bombarding a natural zinc sample with 14 MeV neutrons. We estimated the production yields of 64Cu and 67Cu by fast neutrons from \\text{natC(d,n) with 40 MeV 5 mA deuterons. We used the present result together with the evaluated cross section of Zn isotopes. The calculated 64Cu yield is 1.8 TBq (175 g 64Zn) for 12 h of irradiation; the yields of 67Cu by 67Zn(n,p)67Cu and 68Zn(n,x)67Cu were 249 GBq (184 g 67Zn) and 287 GBq (186 g 68Zn) at the end of 2 days of irradiation, respectively. From the results, we proposed a new route to produce 67Cu with very little radionuclide impurity via the 68Zn(n,x)67Cu reaction, and showed the 64Zn(n,p)64Cu reaction to be a promising route to produce 64Cu. Both 67Cu and 64Cu are noted to be produced using fast neutrons.
The influence of dietary Cu and diabetes on tissue 67Cu retention kinetics in rats

International Nuclear Information System (INIS)

Uriu-Hare, J.Y.; Rucker, R.B.; Keen, C.L.

1991-01-01

Compared to controls, diabetes results in higher plasma, liver and kidney Cu concentrations. Since alterations in Cu metabolism may be associated with diabetic pathology, the authors investigated how Cu metabolism is affected by diabetes and dietary Cu intake. Nondiabetic and STZ diabetic rats were fed Cu suppl. or Cu def. diets for 5 wks. Rats were intubated with 28 μCi 67 Cu and killed after 8, 16, 24, 32, 64, or 128 h. There were marked effects of both diet and diabetes on 67 Cu metabolism. Independent of diabetes, deficient rats had a higher % of retained 67 Cu, in liver, plasma, RBC, muscle, spleen, brain, lung, uterus, and intestine than adequate Cu rats. Independent of dietary Cu, diabetic rats had a lower % of retained 67 Cu in liver, plasma, RBC, muscle, spleen, lung, bone, pancreas, skin, uterus and heart than controls. Differential effects were noted for kidney; adequate Cu diabetic rats had a higher % of retained 67 Cu than all other groups. Marked effects of both diet and diabetes were evident when tissue Cu turnover was examined. Compared to Cu suppl. rats, Cu def. rats had a slower turnover of 67 Cu, in liver, plasma, intestine, pancreas, eye, brain, muscle, spleen, lung and heart. Diabetic rats had a slower turnover of 67 Cu than nondiabetic rats in liver, plasma, intestine, pancreas, eye, kidney, RBC and uterus. The data imply that a focus on Cu metabolism with regard to cellular Cu trafficking and pathology may be warranted
Solution-processed all-oxide bulk heterojunction solar cells based on CuO nanaorod array and TiO2 nanocrystals

Science.gov (United States)

Wu, Fan; Qiao, Qiquan; Bahrami, Behzad; Chen, Ke; Pathak, Rajesh; Tong, Yanhua; Li, Xiaoyi; Zhang, Tiansheng; Jian, Ronghua

2018-05-01

We present a method to synthesize CuO nanorod array/TiO2 nanocrystals bulk heterojunction (BHJ) on fluorine-tin-oxide (FTO) glass, in which single-crystalline p-type semiconductor of the CuO nanorod array is grown on the FTO glass by hydrothermal reaction and the n-type semiconductor of the TiO2 precursor is filled into the CuO nanorods to form well-organized nano-interpenetrating BHJ after air annealing. The interface charge transfer in CuO nanorod array/TiO2 heterojunction is studied by Kelvin probe force microscopy (KPFM). KPFM results demonstrate that the CuO nanorod array/TiO2 heterojunction can realize the transfer of photo-generated electrons from the CuO nanorod array to TiO2. In this work, a solar cell with the structure FTO/CuO nanoarray/TiO2/Al is successfully fabricated, which exhibits an open-circuit voltage (V oc) of 0.20 V and short-circuit current density (J sc) of 0.026 mA cm‑2 under AM 1.5 illumination. KPFM studies indicate that the very low performance is caused by an undesirable interface charge transfer. The interfacial surface potential (SP) shows that the electron concentration in the CuO nanorod array changes considerably after illumination due to increased photo-generated electrons, but the change in the electron concentration in TiO2 is much less than in CuO, which indicates that the injection efficiency of the photo-generated electrons from CuO to TiO2 is not satisfactory, resulting in an undesirable J sc in the solar cell. The interface photovoltage from the KPFM measurement shows that the low V oc results from the small interfacial SP difference between CuO and TiO2 because the low injected electron concentration cannot raise the Fermi level significantly in TiO2. This conclusion agrees with the measured work function results under illumination. Hence, improvement of the interfacial electron injection is primary for the CuO nanorod array/TiO2 heterojunction solar cells.
Cu/sub x/S-CdS thin film solar cells - aftertreatment and stability. Cu/sub x/S-CdS Duennschicht-Solarzellen - Untersuchungen ueber die Nachbehandlung und die Stabilitaet

Energy Technology Data Exchange (ETDEWEB)

Pfisterer, F

1987-02-19

The performance of Cu/sub x/S-CdS thin film solar cells can be improved significantly by a secondary treatment of the Cu layer. The physical mechanisms underlying the aftertreatment process were investigated both experimentally and theoretically. A historical review is followed by an outline of the technology and theory of these solar cells (material properties, process engineering, photovoltaic properties) and a description of Cu aftertreatment and H glowing (experimental set-up, surface potential shift, electron beam scanning). Capacity measurements in this type of thin film cell are described (space charge profile, electrolytic decomposition, copper depletion between the contact web). Aftertreatment of the copper layer enhances the solar cell efficiency, stability, and productivity, makes the immersion process less tedious, and corrects the stoichiometry. (HWJ).
Copper interactions in TlCu7S4 and TlCu7Se4

International Nuclear Information System (INIS)

Noren, L.; Delaplane, R.G.; Berger, R.

1999-01-01

Complete text of publication follows. The copper chalcogenides ACu 7 S 4 (A=NH 4 + , Tl + , Rb + ) are quasi-one-dimensional metals at ambient and higher temperatures which is due to the high mobility of copper in these structures. TlCu 7 S 4 and TlCu 7 Se 4 are isostructural compounds, space group I4/m, which can be described on the basis of a TlX 8 cube with two different Cu sites, Cu(1) and Cu(2). Cu(2)-Cu(2) zigzag chains run along the c axis with only 3/4 occupation of the Cu(2) sites. However, these two compounds differ in behaviour on cooling. The sulphide shows a polymorphic first-order transition to the CsAg 7 S 4 type (P4/n) owing to ordering of the vacancies in the Cu(2)-Cu(2) chains. In order to study the nature of the Cu(2) order/disorder in the two title compounds, a series of neutron diffraction measurements (both Bragg and diffuse scattering) were made at several temperatures from 40 to 713 K on the instrument SLAD at Studsvik. The structure at each temperature was modelled using RMC techniques. The resulting configuration show that as the temperature increases, there is a marked increase in the mobility of the Cu atoms in the Cu(2)-Cu(2) chains for TlCu 7 S 4 but not for TlCu 7 Se 4 . This is due to the initial difference in the Cu(2)-Cu(2) distances, only 2.2A for the thiocuprate, but 2.7A in the selenocuprate which explains the relative ease for Cu(2) ordering in the latter case. (author)
Physical characterization of Cu{sub 2}ZnGeSe{sub 4} thin films from annealing of Cu-Zn-Ge precursor layers

Energy Technology Data Exchange (ETDEWEB)

Buffière, M., E-mail: buffiere@imec.be [Imec—Partner in Solliance, Leuven (Belgium); Department of Electrical Engineering (ESAT), KU Leuven, Heverlee (Belgium); ElAnzeery, H. [Imec—Partner in Solliance, Leuven (Belgium); KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Microelectronics System Design department, Nile University, Cairo (Egypt); Oueslati, S.; Ben Messaoud, K. [Imec—Partner in Solliance, Leuven (Belgium); KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Department of Physics, Faculty of Sciences of Tunis, El Manar (Tunisia); Brammertz, G.; Meuris, M. [Imec Division IMOMEC — Partner in Solliance, Diepenbeek (Belgium); Institute for Material Research (IMO) Hasselt University, Diepenbeek (Belgium); Poortmans, J. [Imec—Partner in Solliance, Leuven (Belgium); Department of Electrical Engineering (ESAT), KU Leuven, Heverlee (Belgium)

2015-05-01

Cu{sub 2}ZnGeSe{sub 4} (CZGeSe) can be considered as a potential alternative for wide band gap thin film devices. In this work, CZGeSe thin films were deposited on Mo-coated soda lime glass substrates by sequential deposition of sputtered Cu, Zn and e-beam evaporated Ge layers from elemental targets followed by annealing at high temperature using H{sub 2}Se gas. We report on the effect of the precursor stack order and composition and the impact of the annealing temperature on the physical properties of CZGeSe thin films. The optimal layer morphology was obtained when using a Mo/Cu/Zn/Ge precursor stack annealed at 460 °C. We have observed that the formation of secondary phases such as ZnSe can be prevented by tuning the initial composition of the stack, the stack order and the annealing conditions. This synthesis process allows synthesizing CZGeSe absorber with an optical band gap of 1.5 eV. - Highlights: • Cu{sub 2}ZnGeSe{sub 4} (CZGeSe) thin films were deposited using a two-step process. • CZGeSe dense layers were obtained using a Mo/Cu/Zn/Ge precursor annealed at 460 °C. • Formation of ZnSe can be avoided by tuning the composition and order of the initial stack. • P-type CZGeSe absorber with an optical band gap of 1.5 eV was obtained.
Behavior of CuP and OFHC Cu anodes under electrodeposition conditions

Energy Technology Data Exchange (ETDEWEB)

Frankel, G.S.; Schrott, A.G.; Horkans, J.; Andricacos, P.C. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center); Isaacs, H.S. (Brookhaven National Lab., Upton, NY (United States))

1992-01-01

Films formed on CuP (with 0.05 wt % P) and OFHC Cu anodes in electroplating solutions were studied by X-ray Photoelectron Spectroscopy, X-ray Absorption Spectroscopy, electrochemical methods, and a newly developed gravimetric technique. The black film formed on CuP in Cl-containing solutions was found to resemble a porous sponge composed of CuCl but laden/with concentrated CuSO{sub 4} solution. The difference between the buoyancy-corrected measured mass change and the charge-equivalent mass change was found to have two components: a reversible part that comes and goes as the current is turned on and off, and an irreversible part that remains on the surface and increase in mass with time. The irreversible part results from the anodic film, which increases linearly with charge density but independent of current density. The reversible part of the mass change arises from the weight of the diffusion layer. In contrast to CuP, OFHC Cu releases much more Cu{sup +1} during anodic polarization and forms a poorly-adherent anodic film that is considerably heavier than the black film for a given charge density.
Behavior of CuP and OFHC Cu anodes under electrodeposition conditions

Energy Technology Data Exchange (ETDEWEB)

Frankel, G.S.; Schrott, A.G.; Horkans, J.; Andricacos, P.C. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center; Isaacs, H.S. [Brookhaven National Lab., Upton, NY (United States)

1992-08-01

Films formed on CuP (with 0.05 wt % P) and OFHC Cu anodes in electroplating solutions were studied by X-ray Photoelectron Spectroscopy, X-ray Absorption Spectroscopy, electrochemical methods, and a newly developed gravimetric technique. The black film formed on CuP in Cl-containing solutions was found to resemble a porous sponge composed of CuCl but laden/with concentrated CuSO{sub 4} solution. The difference between the buoyancy-corrected measured mass change and the charge-equivalent mass change was found to have two components: a reversible part that comes and goes as the current is turned on and off, and an irreversible part that remains on the surface and increase in mass with time. The irreversible part results from the anodic film, which increases linearly with charge density but independent of current density. The reversible part of the mass change arises from the weight of the diffusion layer. In contrast to CuP, OFHC Cu releases much more Cu{sup +1} during anodic polarization and forms a poorly-adherent anodic film that is considerably heavier than the black film for a given charge density.
CuGaTe2-CuAlTe2 system

International Nuclear Information System (INIS)

Bodnar', I.V.

2003-01-01

The results of studies on the chemical interaction in the CuGaTe 2 -CuAlTe 2 as well as on the thermal and optical properties of the formed solid solutions are presented. It is shown, that continuous number of solid solutions are formed in the CuGaTe 2 -CuAlTe 2 system, which crystallize in the chalcopyrite structure. The diagram of state of this system is plotted. The thermal expansion of these materials is studied through the dilatometric method. The linear dependence of the thermal expansion coefficient on the composition is established. The concentration dependences of the forbidden zone width diverge from the linearity [ru
Effect of preparation conditions on the properties of Cu{sub 3}BiS{sub 3} thin films grown by a two - step process

Energy Technology Data Exchange (ETDEWEB)

Mesa, F; Gordillo, G, E-mail: fgmesar@unal.edu.c, E-mail: ggordillog@unal.edu.c [Departamento de Fisica, Universidad Nacional de Colombia, Bogota Cr.30 No 45-03 (Colombia)

2009-05-01

Cu{sub 3}BiS{sub 3} thin films were prepared on soda-lime glass substrates by co-evaporation of the precursors in a two-step process; for that, the metallic precursors were evaporated from a tungsten boat in presence of elemental sulfur evaporated from a tantalum effusion cell. The films were characterized by spectral transmittance, atomic force microscopy AFM and x-ray diffraction (XRD) measurements to investigate the effect of the growth conditions on the optical, morphological and structural properties. The results revealed that, independently of the deposition conditions, the films grow only in the orthorhombic Cu{sub 3}BiS{sub 3} phase. It was also found that the Cu{sub 3}BiS{sub 3} films present p-type conductivity, a high absorption coefficient (greater than 10{sup 4} cm{sup -1}) and an energy band gap Eg of about 1.41 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells.
The effect of inducing uniform Cu growth on formation of electroless Cu seed layer

International Nuclear Information System (INIS)

Lim, Taeho; Kim, Myung Jun; Park, Kyung Ju; Kim, Kwang Hwan; Choe, Seunghoe; Lee, Young-Soo; Kim, Jae Jeong

2014-01-01

The uniformity of Cu growth on Pd nanocatalysts was controlled by using organic additives in the formation of electroless Cu seed layers. Polyethylene glycol (PEG, Mw. 8000) not only reduced the deposition rate but also improved the uniformity of Cu growth on each Pd nanocatalyst during the seed layer formation. The stronger suppression effect of PEG on Cu than on Pd reduced the difference in the deposition rate between the two surfaces, resulting in the uniform deposition. Meanwhile, bis(3-sulfopropyl) disulfide degraded the uniformity by strong and nonselective suppression. The sheet resistance measurement and atomic force microscopy imaging revealed that the uniform Cu growth by PEG was more advantageous for the formation of a thin and smooth Cu seed layer than the non-uniform growth. The uniform Cu growth also had a positive influence on the subsequent Cu electrodeposition: the 60-nm-thick electrodeposited Cu film on the Cu seed layer showed low resistivity (2.70 μΩ·cm), low surface roughness (6.98 nm), and good adhesion strength. - Highlights: • Uniform Cu growth on Pd was achieved in formation of electroless Cu seed layer. • PEG addition to electroless bath improved the uniformity of Cu growth on Pd. • A thin, smooth and continuous Cu seed layer was obtained with PEG. • Adhesion strength of the Cu seed layer was also improved with PEG. • The uniformity improvement positively affected subsequent Cu electrodeposition
Investigations into alterntive substrate, absorber, and buffer layer processing for Cu(In,Ga)Se{sub 2}-based solar cells

Energy Technology Data Exchange (ETDEWEB)

Tuttle, J.R.; Berens, T.A.; Keane, J. [National Renewable Energy Lab., Golden, CO (United States)] [and others

1996-05-01

High-performance Cu(In,Ga)Se{sub 2}(CIGS)-based solar cells are presently fabricated within a narrow range of processing options. In this contribution, alternative substrate, absorber, and buffer layer processing is considered. Cell performance varies considerably when alternative substrates are employed. These variations are narrowed with the addition of Na via a Na{sub 2}S compound. Sputtered and electrodeposited CIGS precursors and completed absorbers show promise as alternatives to evaporation. A recrystallization process is required to improve their quality. (In,Ga){sub y}Se buffer layers contribute to cell performance above 10. Further improvements in these alternatives will lead to combined cell performance greater than 10% in the near term.

Colloidal synthesis of Cu-ZnO and Cu@CuNi-ZnO hybrid nanocrystals with controlled morphologies and multifunctional properties

Science.gov (United States)

Zeng, Deqian; Gong, Pingyun; Chen, Yuanzhi; Zhang, Qinfu; Xie, Qingshui; Peng, Dong-Liang

2016-06-01

Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications. The utilization of low-cost non-noble metals to construct novel metal-semiconductor hybrid nanocrystals is important and meaningful for their large-scale applications. In this study, a facile solution approach is developed for the synthesis of Cu-ZnO hybrid nanocrystals with well-controlled morphologies, including nanomultipods, core-shell nanoparticles, nanopyramids and core-shell nanowires. In the synthetic strategy, Cu nanocrystals formed in situ serve as seeds for the heterogeneous nucleation and growth of ZnO, and it eventually forms various Cu-ZnO hetero-nanostructures under different reaction conditions. These hybrid nanocrystals possess well-defined and stable heterostructure junctions. The ultraviolet-visible-near infrared spectra reveal morphology-dependent surface plasmon resonance absorption of Cu and the band gap absorption of ZnO. Furthermore, we construct a novel Cu@CuNi-ZnO ternary hetero-nanostructure by incorporating the magnetic metal Ni into the pre-synthesized colloidal Cu nanocrystals. Such hybrid nanocrystals possess a magnetic Cu-Ni intermediate layer between the ZnO shell and the Cu core, and exhibit ferromagnetic/superparamagnetic properties which expand their functionalities. Finally, enhanced photocatalytic activities are observed in the as-prepared non-noble metal-ZnO hybrid nanocrystals. This study not only provides an economical way to prepare high-quality morphology-controlled Cu-ZnO hybrid nanocrystals for potential applications in the fields of photocatalysis and photovoltaic devices, but also opens up new opportunities in designing ternary non-noble metal-semiconductor hybrid nanocrystals with multifunctionalities.Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications
One-step synthesis and microstructure of CuO-SDC composites

Energy Technology Data Exchange (ETDEWEB)

Firmino, H.C.T.; Araujo, A.J.M.; Dutra, R.P.S.; Macedo, D.A., E-mail: hellentorrano@hotmail.com, E-mail: allanjp1993@hotmail.com, E-mail: ricardopsd@gmail.com, E-mail: damaced@gmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Nascimento, R.M., E-mail: rmaribondo@ufrnet.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Rajesh, S., E-mail: rajeshayr@gmail.com [University of Aveiro (Portugal)

2017-01-15

An in situ one step synthesis route based on the polymeric precursor method was used to produce dual phase CuO-samaria doped ceria (SDC) nanocomposite powders. This chemical route allowed to obtain composite powders with reduced particle size and uniform distribution of Cu, Ce and Sm elements. The particulate material was characterized by powder X-ray diffraction (XRD) combined with Rietveld refinement. CuO-SDC sintered in air between 950 to 1050 °C and subsequently reduced to Cu-SDC cermets were further characterized by XRD and scanning electron microscopy. The open porosity was measured using the Archimedes' principle. Suitable microstructures for both charge transfer and mass transport processes (30 to 45% porosity) were attained in Cu-SDC cermets previously fired at 1000 to 1050 °C. Overall results indicated that CuO-SDC composites and Cu-SDC cermets with potential application as anodes for solid oxide fuel cells (SOFCs) can be obtained by microstructural design. An anode supported half-cell was prepared by co-pressing and co-firing gadolinia doped ceria (CGO) and the herein synthesized CuO-SDC nanocomposite powder. (author)
Molecular dynamics simulation of diffusion bonding of Al–Cu interface

International Nuclear Information System (INIS)

Li, Chang; Li, Dongxu; Tao, Xiaoma; Chen, Hongmei; Ouyang, Yifang

2014-01-01

The effects of temperature on diffusion bonding of Al–Cu interface have been investigated by using molecular dynamics (MD) technique with the embedded atomic method (EAM) potentials. The simulated results indicate that the Cu atoms predominantly diffuse into the Al side in the process of diffusion bonding, and the thickness of the interfacial region depends on temperature, with higher temperatures resulting in larger thickness. In the course of diffusion bonding, the interfacial region became disordered. In addition, the Cu atoms diffuse at low ratios but can deeply diffuse into the interior of Al, and the Al atoms diffuse at high ratios but hardly diffuse into the interior of Cu. The results show that the appropriate temperature range for diffusion bonding of Al–Cu interface is 750–800 K, and the diffusion activation energies of Al and Cu are 0.77 eV and 0.50 eV, respectively. Finally, in this work, three diffusion mechanisms of Cu atoms in Al lattice have been found and the main diffusion mechanism is the nearest neighbor hopping mechanism. (paper)
Phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram

International Nuclear Information System (INIS)

Zeng, K.J.; Haemaelaeinen, M.; Lilius, K.

1995-01-01

In the available experimental information on the Cu-Cr-Zr ternary system, there exist different opinions concerning the phase relationships in the Cu-rich corner of Cu-Cr-Zr phase diagram. Glazov et al. and Zakharov et al. investigated the Cu-rich corner of the Cu-Cr-Zr phase diagram within the composition range up to 3.5 Cr and 3.5 Zr (wt. %). A quasi-eutectic reaction L → (Cu) + αCr 2 Zr was observed to occur at 1,020 C and several isothermal sections were constructed within the temperature range from 600 to 1,000 C to show the (Cu)-αCr 2 Zr two phase equilibrium. Therefore, a pseudobinary Cu-Cr 2 Zr system was supposed. Afterwards, Dawakatsu et al, Fedorov et al, and Kuznetsov et al studied the cu-rich corner of the phase diagram in a wider composition range up to 5 Cr and 20 Zr (at.%). Contrary to Glazov et al. and Zakharov et al., they found no Cr 2 Zr phase in their samples. Hence, the pseudobinary Cu-Cr 2 Zr system does not exist. In this study an experimental investigation is presented on the phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram at 940 C in order to clear up the confusion
Fabrication of high-quality single-crystal Cu thin films using radio-frequency sputtering.

Science.gov (United States)

Lee, Seunghun; Kim, Ji Young; Lee, Tae-Woo; Kim, Won-Kyung; Kim, Bum-Su; Park, Ji Hun; Bae, Jong-Seong; Cho, Yong Chan; Kim, Jungdae; Oh, Min-Wook; Hwang, Cheol Seong; Jeong, Se-Young

2014-08-29

Copper (Cu) thin films have been widely used as electrodes and interconnection wires in integrated electronic circuits, and more recently as substrates for the synthesis of graphene. However, the ultra-high vacuum processes required for high-quality Cu film fabrication, such as molecular beam epitaxy (MBE), restricts mass production with low cost. In this work, we demonstrated high-quality Cu thin films using a single-crystal Cu target and radio-frequency (RF) sputtering technique; the resulting film quality was comparable to that produced using MBE, even under unfavorable conditions for pure Cu film growth. The Cu thin film was epitaxially grown on an Al2O3 (sapphire) (0001) substrate, and had high crystalline orientation along the (111) direction. Despite the 10(-3) Pa vacuum conditions, the resulting thin film was oxygen free due to the high chemical stability of the sputtered specimen from a single-crystal target; moreover, the deposited film had >5× higher adhesion force than that produced using a polycrystalline target. This fabrication method enabled Cu films to be obtained using a simple, manufacturing-friendly process on a large-area substrate, making our findings relevant for industrial applications.
Hydrodynamic evolution and jet energy loss in Cu + Cu collisions

International Nuclear Information System (INIS)

Schenke, Bjoern; Jeon, Sangyong; Gale, Charles

2011-01-01

We present results from a hybrid description of Cu + Cu collisions using (3 + 1)-dimensional hydrodynamics (music) for the bulk evolution and a Monte Carlo simulation (martini) for the evolution of high-momentum partons in the hydrodynamical background. We explore the limits of this description by going to small system sizes and determine the dependence on different fractions of wounded nucleon and binary collisions scaling of the initial energy density. We find that Cu + Cu collisions are well described by the hybrid description at least up to 20% central collisions.
Massive spalling of Cu-Zn and Cu-Al intermetallic compounds at the interface between solders and Cu substrate during liquid state reaction

Science.gov (United States)

Kotadia, H. R.; Panneerselvam, A.; Mokhtari, O.; Green, M. A.; Mannan, S. H.

2012-04-01

The interfacial intermetallic compound (IMC) formation between Cu substrate and Sn-3.8Ag-0.7Cu-X (wt.%) solder alloys has been studied, where X consists of 0-5% Zn or 0-2% Al. The study has focused on the effect of solder volume as well as the Zn or Al concentration. With low solder volume, when the Zn and Al concentrations in the solder are also low, the initial Cu-Zn and Al-Cu IMC layers, which form at the solder/substrate interface, are not stable and spall off, displaced by a Cu6Sn5 IMC layer. As the total Zn or Al content in the system increases by increasing solder volume, stable CuZn or Al2Cu IMCs form on the substrate and are not displaced. Increasing concentration of Zn has a similar effect of stabilizing the Cu-Zn IMC layer and also of forming a stable Cu5Zn8 layer, but increasing Al concentration alone does not prevent spalling of Al2Cu. These results are explained using a combination of thermodynamic- and kinetics-based arguments.
Enhanced electrical properties of pulsed laser-deposited CuIn{sub 0.7}Ga{sub 0.3}Se{sub 2} thin films via processing control

Energy Technology Data Exchange (ETDEWEB)

Jo, Yeon Hwa; Mohanty, Bhaskar Chandra; Cho, Yong Soo [Department of Materials Science and Engineering, Yonsei University, Seoul (Korea, Republic of)

2010-12-15

Polycrystalline CuIn{sub 0.7}Ga{sub 0.3}Se{sub 2} thin films were prepared on soda-lime glass substrates using pulsed laser deposition (PLD) with various process parameters such as laser energy, repetition rate and substrate temperature. It was confirmed that there existed a limited laser energy, i.e. less than 300 mJ, to get phase pure CIGS thin films at room temperature. Particularly, even at room temperature, distinct crystalline CIGS phase was observed in the films. Crystallinity of the films improved with increasing substrate temperature as evidenced by the decrease of FWHM from 0.65 degto 0.54 deg. Slightly Cu-rich surface with Cu{sub 2-x}Se phase was confirmed to exist by Raman spectra, depending on substrate temperature. Improved electrical properties, i.e., carrier concentration of {proportional_to}10{sup 18} cm{sup -3} and resistivity of 10{sup -1}{omega} cm at higher substrate temperature for the optimal CIGS films are assumed to be induced by the potential contributions from highly crystallized thin films, existence of Cu{sub 2-x}Se phase and diffusion of Na from substrates to films. (author)
Copper isotopic zonation in the Northparkes porphyry Cu-Au deposit, SE Australia

Science.gov (United States)

Li, Weiqiang; Jackson, Simon E.; Pearson, Norman J.; Graham, Stuart

2010-07-01

Significant, systematic Cu isotopic variations have been found in the Northparkes porphyry Cu-Au deposit, NSW, Australia, which is an orthomagmatic porphyry Cu deposit. Copper isotope ratios have been measured in sulfide minerals (chalcopyrite and bornite) by both solution and laser ablation multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The results from both methods show a variation in δ 65Cu of hypogene sulfide minerals of greater than 1‰ (relative to NIST976). Significantly, the results from four drill holes through two separate ore bodies show strikingly similar patterns of Cu isotope variation. The patterns are characterized by a sharp down-hole decrease from up to 0.8‰ (0.29 ± 0.56‰, 1 σ, n = 20) in the low-grade peripheral alteration zones (phyllic-propylitic alteration zone) to a low of ˜-0.4‰ (-0.25 ± 0.36‰, 1 σ, n = 30) at the margins of the most mineralized zones (Cu grade >1 wt%). In the high-grade cores of the systems, the compositions are more consistent at around 0.2‰ (0.19 ± 0.14‰, 1 σ, n = 40). The Cu isotopic zonation may be explained by isotope fractionation of Cu between vapor, solution and sulfides at high temperature, during boiling and sulfide precipitation processes. Sulfur isotopes also show an isotopically light shell at the margins of the high-grade ore zones, but these are displaced from the low δ 65Cu shells, such that there is no correlation between the Cu and S isotope signatures. Fe isotope data do not show any discernable variation along the drill core. This work demonstrates that Cu isotopes show a large response to high-temperature porphyry mineralizing processes, and that they may act as a vector to buried mineralization.
Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis.

Science.gov (United States)

Gawande, Manoj B; Goswami, Anandarup; Felpin, François-Xavier; Asefa, Tewodros; Huang, Xiaoxi; Silva, Rafael; Zou, Xiaoxin; Zboril, Radek; Varma, Rajender S

2016-03-23

The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications in catalysis. The synthesis part discusses numerous preparative protocols for Cu and Cu-based nanoparticles, whereas the application sections describe their utility as catalysts, including electrocatalysis, photocatalysis, and gas-phase catalysis. We believe this critical appraisal will provide necessary background information to further advance the applications of Cu-based nanostructured materials in catalysis.
Facile Synthesis of Colloidal CuO Nanocrystals for Light-Harvesting Applications

KAUST Repository

Lim, Yee-Fun; Choi, Joshua J.; Hanrath, Tobias

2012-01-01

CuO is an earth-abundant, nontoxic, and low band-gap material; hence it is an attractive candidate for application in solar cells. In this paper, a synthesis of CuO nanocrystals by a facile alcohothermal route is reported. The nanocrystals are dispersible in a solvent mixture of methanol and chloroform, thus enabling the processing of CuO by solution. A bilayer solar cell comprising of CuO nanocrystals and phenyl-C61-butyric acid methyl ester (PCBM) achieved a power conversion efficiency of 0.04%, indicating the potential of this material for light-harvesting applications.
Elaboration and characterization of silver sheathed YBaCuO and BiSrCaCuO wires

International Nuclear Information System (INIS)

Regnier, P.; Chaffron, L.; Schmirgeld, L.

1990-01-01

We report on our recent progress in the elaboration of silver sheathed high-Tc superconducting wires. It is shown that careful optimization of the swaging and pressing stages leads to a compacity of nearly 100% for the green ceramic, which considerably reduces the problem of its shrinkage in the silver clad during sintering, and consequently increases the critical current density far above 10 3 A/cm 2 at 77 K. Electrical and microstructural characterization of the wires are presented and compared with other published data. In particular, for both YBaCuO and BiSrCaCuO ribbons, it is shown that the thinner the ribbon the higher the critical current density. But this effect is much more pronounced for BiSrCaCuO because, due to partial melting of the former ceramic during the elaboration process, there is a pronounced enhancement of its texture as its thickness is reduced
Corrosion and wear behavior of Ni60CuMoW coatings fabricated by combination of laser cladding and mechanical vibration processing

Energy Technology Data Exchange (ETDEWEB)

Liu, Hongxi, E-mail: piiiliuhx@sina.com [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Xu, Qian [Faculty of Adult Education, Kunming University of Science and Technology, Kunming 650051 (China); Wang, Chuanqi; Zhang, Xiaowei [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

2015-02-05

Highlights: • Ni60CuMoW coatings were fabricated by mechanical vibration assisted laser cladding hybrid process. • The maximum micro-hardness of the coating with mechanical vibration increases by 16%. • The mass loss and friction coefficient of the coating decreases by 17% and 16%, respectively. • The E{sub corr} positive shifts 1134.9 mV and i{sub corr} decreases by nearly one order of magnitude. • The ideal vibration parameters is vibration frequency 200 Hz and vibration amplitude 140 μm. - Abstract: Ni60CuMoW composite coatings were fabricated on 45 medium carbon steel using mechanical vibration assisted laser cladding surface modification processing. The microstructure, element distribution, phase composition, microhardness, wear and corrosion resistance of cladding coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), hardness tester, friction and wear apparatus and electrochemical workstation. The results indicate that the microstructure of M{sub 23}C{sub 6} (Cr{sub 23}C{sub 6} or (Fe, Ni){sub 23}C{sub 6}) carbide dispersion strengthening phase is uniformly distributed in eutectic (Ni, Fe) phase. The in-situ BCr and MoC compounds distribute in lamellar structure Fe{sub 3}B and dendrite Fe{sub 3}Ni{sub 3}Si, and some new W{sub 2}C phases also generated in Ni60CuMoW coating. In addition, the coarse dendrite has been replaced by some fine grain structure at the bonding interface. The fine grain hard phase makes the average microhardness of cladding coating increase from 720 to 835 HV{sub 0.5}. Under the condition of 200 Hz mechanical vibration frequency, the wear mass loss and friction coefficient of Ni60CuMoW coating are 7.6 mg and 0.068, 17% and 16% lower than the coating without mechanical vibration, respectively. The corrosion potential of cladding coating with mechanical vibration increases by 1134.9 mV and the corrosion current density decreases by nearly one order of
New alternative methods of analyzing human behavior in cued target acquisition.

Science.gov (United States)

Maltz, Masha; Shinar, David

2003-01-01

Target acquisition tasks in natural environments are often augmented by cuing systems that advise human observers during the decision process. With present technological limitations, cuing systems are imperfect, so the question arises whether cuing aids should be implemented under all conditions. We examined target acquisition performance under different levels of task complexity and cuing system reliability. We introduce here two new methods to help define observer behavior trends in cued target acquisition: a quantitative measure of observer search behavior in a temporal sense and a measure of the extent of observer reliance on the cue. We found that observer reliance on the cue correlated with task difficulty and the perceived reliability of the cue. Cuing was generally helpful in complex tasks, whereas cuing reduced performance in easy tasks. Consequently, cuing systems should be implemented only when the task is difficult enough to warrant the intrusion of a cue into the task. Actual or potential applications of this research include the design and implementation of imperfect automated aids dealing with augmented reality.
Electromagnetic Stirring versus ECAP: Morphological Comparison of Al-Si-Cu Alloys to Make the Microstructural Refinement for Use in SSM Processing

Directory of Open Access Journals (Sweden)

Luis Vanderlei Torres

2016-01-01

Full Text Available This work evaluates the morphological evolution at the semisolid state of the Al-4.0wt%Si-2.5wt%Cu alloy produced by direct chill casting under electromagnetic stirring (EMS and by one equal channel angular pressing (ECAP pass. The ECAP emerged as a promising technique capable of reduction and homogeneous metals microstructure imposing large deformations occurs in a matrix that contains two channels of the same cross-sectional area and forms an angle of 120°. The materials were submitted to reheating treatment in condition of 60% solid fraction at treatment times of 0, 30, and 90 s. Comparing the two cases, we have the presented ECAP process that had an excellent response to the recovery and recrystallization mechanisms, and refined microstructures ideal for thixoforming were produced. Primary particle sizes of about 45 μm and grain sizes of about 75 μm and a circularity shape factor of more than 0.60 were obtained. The low silicon alloy, Al-4.0wt%Si-2.5wt%Cu, presented excellent refinement when processed via equal channel angular pressing, presenting good morphological stability at the semisolid state, without significant changes in size or shape of the solid particles. This fully globular structure is favourable for thixoforming processes.
Cu uptake and turnover in both Cu-acclimated and non-acclimated rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Grosell, M.; Hogstrand, C.; Wood, C.M.

1997-01-01

-acclimation clearly involves changes in copper accumulation kinetics in the plasma. The acclimated fish showed a 65% reduced Cu-64 accumulation after 65 h and an increased turnover of Cu in the plasma compared to the non-acclimated fish. Total Cu in the plasma increased by 59% after 3 h of exposure in the non...... aortic catheter. By measuring both Cu-64 accumulation and total Cu concentrations, we were able to analyse the ongoing uptake and turnover of ambient Cu, independent of any Cu already present in the fish. Plasma accounted for at least 90% of the Cu-64 labelled Cu present in the blood and Cu...... h of exposure. Acclimation did not have an unambiguous effect on branchial Cu uptake and differences in branchial uptake could not explain the reduced accumulation in the plasma. The rapidly exchangeable Cu pools were 54% in the gills and 33% in the liver, suggesting a considerable hepatic Cu...
Fabrication of CuInS2-sensitized solar cells via an improved SILAR process and its interface electron recombination.

Science.gov (United States)

Xu, Xueqing; Wan, Qingcui; Luan, Chunyan; Mei, Fengjiao; Zhao, Qian; An, Ping; Liang, Zhurong; Xu, Gang; Zapien, Juan Antonio

2013-11-13

Tetragonal CuInS2 (CIS) has been successfully deposited onto mesoporous TiO2 films by in-sequence growth of InxS and CuyS via a successive ionic layer absorption and reaction (SILAR) process and postdeposition annealing in sulfur ambiance. X-ray diffraction and Raman measurements showed that the obtained tetragonal CIS consisted of a chalcopyrite phase and Cu-Au ordering, which related with the antisite defect states. For a fixed Cu-S deposition cycle, an interface layer of β-In2S3 formed at the TiO2/CIS interface with suitable excess deposition of In-S. In the meantime, the content of the Cu-Au ordering phase decreased to a reasonable level. These facts resulted in the retardance of electron recombination in the cells, which is proposed to be dominated by electron transfer from the conduction band of TiO2 to the unoccupied defect states in CIS via exponentially distributed surface states. As a result, a relatively high efficiency of ~0.92% (V(oc) = 0.35 V, J(sc) = 8.49 mA cm(-2), and FF = 0.31) has been obtained. Last, but not least, with an overloading of the sensitizers, a decrease in the interface area between the sensitized TiO2 and electrolytes resulted in deceleration of hole extraction from CIS to the electrolytes, leading to a decrease in the fill factor of the solar cells. It is indicated that the unoccupied states in CIS with energy levels below EF0 of the TiO2 films play an important role in the interface electron recombination at low potentials and has a great influence on the fill factor of the solar cells.
Evaluating print performance of Sn-Ag-Cu lead-free solder pastes used in electronics assembly process

Science.gov (United States)

Mallik, S.; Bauer, R.; Hübner, F.; Ekere, N. N.

2011-01-01

Solder paste is the most widely used interconnection material in the electronic assembly process for attaching electronic components/devices directly onto the surface of printed circuit boards, using stencil printing process. This paper evaluates the performance of three different commercially available Sn-Ag-Cu solder pastes formulated with different particle size distributions (PSD), metal content and alloy composition. A series of stencil printing tests were carried out using a specially designed stencil of 75 μm thickness and apertures of 300×300 μm2 dimension and 500 μm pitch sizes. Solder paste printing behaviors were found related to attributes such as slumping and surface tension and printing performance was correlated with metal content and PSD. The results of the study should benefit paste manufacturers and SMT assemblers to improve their products and practices.
Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

International Nuclear Information System (INIS)

Wang, Kunchan; Xia, Ming; Xiao, Tao; Lei, Ting; Yan, Weishan

2017-01-01

Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.
Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

Energy Technology Data Exchange (ETDEWEB)

Wang, Kunchan; Xia, Ming [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Xiao, Tao [2nd Xiangya Hospital, Central South University, Changsha 410011 (China); Lei, Ting, E-mail: tlei@mail.csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Yan, Weishan [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

2017-01-15

Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.

Critical current density in (YBa2Cu3O7-δ)1-x-(PrBa2Cu3O7-δ)x melt-textured composites

Science.gov (United States)

Opata, Yuri Aparecido; Monteiro, João Frederico Haas Leandro; Jurelo, Alcione Roberto; Siqueira, Ezequiel Costa

2018-06-01

Melt textured (YBa2Cu3O7-δ)1-x-(PrBa2Cu3O7-δ)x composites (x = 0.00 and x = 0.05) were grown using the top seeding method. The effect of the PrBa2Cu3O7-δ phase on the growth process and the modification of the microstructure as well as on the physical properties was analyzed. X-ray analyses indicated that both pure and Pr-doped samples present an orthorhombic superconducting phase. From resistivity measurements for YBa2Cu3O7-δ and (YBa2Cu3O7-δ)0.95-(PrBa2Cu3O7-δ)0.05 samples, the Tcab did not change and was around 90.5 K. However, from magnetic measurements, the superconductivity was observed in critical temperatures TC = 92.9 K and 92.4 K for YBa2Cu3O7-δ and (YBa2Cu3O7-δ)0.95-(PrBa2Cu3O7-δ)0.05 samples, respectively. The YBa2Cu3O7-δ sample showed higher critical current densities than those shown by the (YBa2Cu3O7-δ)0.95-(PrBa2Cu3O7-δ)0.05 sample, with values of JC = 5.85 × 105 A/cm2 and 4.72 × 105 A/cm2, respectively. This paper also discusses the importance of Pr substitution on nano- and micro-meter scales to enhance JC(H).
Age-hardening of an Al-Li-Cu-Mg alloy (2091) processed by high-pressure torsion

Energy Technology Data Exchange (ETDEWEB)

Lee, Seungwon, E-mail: chominamlsw@gmail.com [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); WPI, International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka 819-0395 (Japan); Horita, Zenji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); WPI, International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka 819-0395 (Japan); Hirosawa, Shoichi [Department of Mechanical Engineering and Materials Science, Yokohama National University, Yokohama 240-8501 (Japan); Matsuda, Kenji [Graduate School of Science and Engineering for Research, University of Toyama, Toyama 930-8555 (Japan)

2012-06-01

This research presents the successful strengthening of an Al-Li-Cu-Mg alloy (2091) through the simultaneous use of grain refinement and age hardening. Following solid-solution treatment, the alloy was processed by high-pressure torsion (HPT) at room temperature and the grain size was refined to {approx}140 nm. The Vickers microhardness increased with increasing strain, and saturated to a constant level of 225 Hv. A further increase in the hardness to {approx}275 Hv was achieved by aging the HPT-processed alloy at 100 Degree-Sign C and 150 Degree-Sign C. Bending tests for the samples treated using the peak aging conditions demonstrated that the stress was significantly increased while considerable ductility was retained. Transmission electron microscopy revealed that the small grains are well retained even after prolonged aging, and the precipitation of fine {delta} Prime particles occurred within the small grains, which confirms that simultaneous strengthening from grain refinement and age hardening is feasible in this alloy.
Controllable growth and photocatalytic activity of Cu{sub 2}O solid microspheres

Energy Technology Data Exchange (ETDEWEB)

Gao, Hong; Zhang, Junying, E-mail: zjy@buaa.edu.cn; Wang, Mei

2013-09-01

Graphical abstract: - Highlights: • 3 μm uniform Cu{sub 2}O solid microspheres with abundant nanopores are achieved. • NH{sub 2}OH·HCl and SDS are main factors that manipulate morphologies of Cu{sub 2}O particles. • Surface features of microspheres influenced the photocatalytic activity of Cu{sub 2}O. • Microspheres are transforming to polyhedrons with extended holding time. - Abstract: A series of Cu{sub 2}O solid microspheres with different surface features were prepared and their photocatalytic activities were studied. The experiment conditions were investigated and the formation mechanism was explored systematically. It was found that varying the amounts of NH{sub 2}OH·HCl reductant in alkaline solutions changed the reaction process and thus altered the surface features of Cu{sub 2}O microspheres. Sodium dodecyl sulfate (SDS) surfactant, introduced as a morphology directing agent, caused the nuclei aggregation and growth process of Cu{sub 2}O solid microspheres by precisely realizing the opposite charges’ directional attraction. This SDS-mediated method can be readily extended to synthesizing solid microspheres of other metal oxides. Meanwhile, it was found that Cu{sub 2}O solid microspheres with abundant nanopores on the surface showed much higher efficient catalytic activity for decoloring methyl orange (MO) aqueous solution than with other surface features under visible light irradiation. Furthermore, we found that prolonging the holding time made Cu{sub 2}O microspheres transform to polyhedrons.
Crystallization-mediated amorphous Cu_xO (x = 1, 2)/crystalline CuI p–p type heterojunctions with visible light enhanced and ultraviolet light restrained photocatalytic dye degradation performance

International Nuclear Information System (INIS)

Wang, Hongli; Cai, Yun; Zhou, Jian; Fang, Jun; Yang, Yang

2017-01-01

Highlights: • Cu_xO(x = 1, 2)/CuI p–p type heterojunctions were facilely constructed via crystallization-mediated approaches. • Cu_xO/CuI heterojunctions exhibit effective visible-light-driven photocatalytic activity for dye degradation. • The Cu_xO/CuI interface can enhance the spatial separation of the photogenerated electron–hole pairs. • This work represents a critical step for mass production of functional semiconductor heterojunctions in a mild manner. - Abstract: We report simple and cost-effective fabrication of amorphous Cu_xO (x = 1, 2)/crystalline CuI p–p type heterojunctions based on crystallization-mediated approaches including antisolvent crystallization and crystal reconstruction. Starting from CuI acetonitrile solution, large crystals in commercial CuI can be easily converted to aggregates consisting of small particles by the crystallization processes while the spontaneous oxidation of CuI by atmospheric/dissolved oxygen can induce the formation of trace Cu_xO on CuI surface. As a proof of concept, the as-fabricated Cu_xO/CuI heterojunctions exhibit effective photocatalytic activity towards the degradation of methyl blue and other organic pollutants under visible light irradiation, although the wide band-gap semiconductor CuI is insensible to visible light. Unexpectedly, the Cu_xO/CuI heterojunctions exhibit restrained photocatalytic activity when ultraviolet light is applied in addition to the visible. It is suggested that the Cu_xO/CuI interface can enhance the spatial separation of the electron–hole pairs with the excitation of Cu_xO under visible light and prolong the lifetime of photogenerated charges with high redox ability. The present work represents a critically important step in advancing the crystallization technique for potential mass production of semiconductor heterojunctions in a mild manner.
Bimetallic AgCu/Cu2O hybrid for the synergetic adsorption of iodide from solution.

Science.gov (United States)

Mao, Ping; Liu, Ying; Liu, Xiaodong; Wang, Yuechan; Liang, Jie; Zhou, Qihang; Dai, Yuexuan; Jiao, Yan; Chen, Shouwen; Yang, Yi

2017-08-01

To further improve the capacity of Cu 2 O to absorb I - anions from solution, and to understand the difference between the adsorption mechanisms of Ag/Cu 2 O and Cu/Cu 2 O adsorbents, bimetallic AgCu was doped into Cu 2 O through a facile solvothermal route. Samples were characterized and employed to adsorb I - anions under different experimental conditions. The results show that the Cu content can be tuned by adding different volumes of Ag sols. After doping bimetallic AgCu, the adsorption capacity of the samples can be increased from 0.02 mmol g -1 to 0.52 mmol g -1 . Moreover, the optimal adsorption is reached within only 240 min. Meanwhile, the difference between the adsorption mechanisms of Ag/Cu 2 O and Cu/Cu 2 O adsorbents was verified, and the cooperative adsorption mechanism of the AgCu/Cu 2 O hybrid was proposed and verified. In addition, the AgCu/Cu 2 O hybrid showed excellent selectivity, e.g., its adsorption efficiencies are 85.1%, 81.9%, 85.9% and 85.7% in the presence of the Cl - , CO 3 2- , SO 4 2- and NO 3 - competitive anions, respectively. Furthermore, the AgCu/Cu 2 O hybrid can worked well in other harsh environments (e.g., acidic, alkaline and seawater environments). Therefore, this study is expected to promote the development of Cu 2 O into a highly efficient adsorbent for the removal of iodide from solution. Copyright © 2017 Elsevier Ltd. All rights reserved.
YBa2Cu3O7-δ/NdBa2(Cu1-xNix)3O7-δ double layers by liquid-phase epitaxial growth

International Nuclear Information System (INIS)

Yao, X.; Izumi, Toru; Hobara, Natsuro; Nakamura, Yuichi; Izumi, Teruo; Shiohara, Yuh

2001-01-01

Our present investigation has answered questions pertaining to the REBa 2 Cu 3 O 7-δ (RE123, RE=rare-earth elements)-coated conductor application when NdBa 2 (Cu 1-x Ni x ) 3 O 7-δ (Ni-NdBCO) solid solution is used as a buffer layer by the liquid-phase epitaxy(LPE) process. The NiO/Ni substrate has no substantial reaction in the Ni-saturated Nd-Ba-Cu-O liquid. There is no essential Ni interdiffusion between YBa 2 Cu 3 O 7-δ (YBCO) and Ni-NdBCO LPE thick films as evident from T c values of 90 K obtained from multilayer YBCO/Ni-NdBCO samples. (author)
Crystallization and electrical resistivity of Cu2O and CuO obtained by thermal oxidation of Cu thin films on SiO2/Si substrates

International Nuclear Information System (INIS)

De Los Santos Valladares, L.; Salinas, D. Hurtado; Dominguez, A. Bustamante; Najarro, D. Acosta; Khondaker, S.I.; Mitrelias, T.; Barnes, C.H.W.; Aguiar, J. Albino; Majima, Y.

2012-01-01

In this work, we study the crystallization and electrical resistivity of the formed oxides in a Cu/SiO 2 /Si thin film after thermal oxidation by ex-situ annealing at different temperatures up to 1000 °C. Upon increasing the annealing temperature, from the X ray diffractogram the phase evolution Cu → Cu + Cu 2 O → Cu 2 O → Cu 2 O + CuO → CuO was detected. Pure Cu 2 O films are obtained at 200 °C, whereas uniform CuO films without structural surface defects such as terraces, kinks, porosity or cracks are obtained in the temperature range 300–550 °C. In both oxides, crystallization improves with annealing temperature. A resistivity phase diagram, which is obtained from the current–voltage response, is presented here. The resistivity was expected to increase linearly as a function of the annealing temperature due to evolution of oxides. However, anomalous decreases are observed at different temperatures ranges, this may be related to the improvement of the crystallization and crystallite size when the temperature increases. - Highlights: ► The crystallization and electrical resistivity of oxides in a Cu films are studied. ► In annealing Cu films, the phase evolution Cu + Cu 2 O → Cu 2 O → Cu 2 O + CuO → CuO occurs. ► A resistivity phase diagram, obtained from the current–voltage response, is presented. ► Some decreases in the resistivity may be related to the crystallization.
Ionic liquids-modulated two-phase thermal synthesis of three-dimensional CuS nanostructures

International Nuclear Information System (INIS)

Yao, Kaisheng; Lu, Weiwei; Li, Xinying; Wang, Jianji

2012-01-01

A novel method was proposed for successful fabrication of CuS nanostructures with various morphologies. At the ionic liquids (ILs)-modulated CHCl 3 –H 2 O interface, copper cupferronate [Cu(cup) 2 ] in CHCl 3 reacted with thiourea in water to generate CuS nanostructures via a solvothermal reaction process. The effects of alkyl chain length of imidazolium cations and nature of anions of the ILs, molar ratio of Cu(cup) 2 to thiourea, the reaction temperature and time on the morphology of the products were studied systematically. It was shown that by changing alkyl chain length of imidazolium cations and nature of anions of the ILs, CuS nanostructures with various morphologies, including flowers, urchins, large nanodisks and nanoparticles, could be obtained at the liquid–liquid interface, and the ILs played important template roles in directing the formation of CuS nanostructures. Furthermore, the as-prepared CuS samples exhibited high catalytic activity for photodegradation of methyl orange and thermal decomposition of ammonium perchlorate. - Graphical abstract: At the ionic liquids-modulated CHCl 3 –H 2 O interface, the CuS nanostructures with the various morphologies of flowers, urchins, large nanodisks and nanoparticles have been successfully prepared via a solvothermal reaction process. Highlights: ► The properties of oil–H 2 O interface can be modulated by employing different ILs. ► The modulated interface has been used to prepare CuS nanostructures with various morphologies. ► The CuS samples exhibited high catalytic activity for the photodegradation of methyl orange.
Polarographic study of the Cu(II)/Cu(I) system in the presence of 1-ascorbic acid and 0,1 M ClK

International Nuclear Information System (INIS)

Alonso Lopez, J.

1969-01-01

While studying the catalytic effect of Cu ↓ 2 ions on the oxidation process of 1-ascorbic acid, it has been observed that, in a 0,1 M solution of K1 at a pH 6 to 7, the above acid gives rise in the presence of Cu ↓ 2 ions to a polarographic wave of half-wave potential of -0,41 V (vs. S.C.E.). (Author) 14 refs
Effects of plasma cleaning of the Cu seed layer surface on Cu electroplating

International Nuclear Information System (INIS)

O, Jun Hwan; Lee, Seong Wook; Kim, Jae Bum; Lee, Chong Mu

2001-01-01

Effects of plasma pretreatment to Cu seed/tantalum nitride (TaN)/ borophosphosilicate glass (BPSG) samples on copper (Cu) electroplating were investigated. Copper seed layers were deposited by magnetron sputtering onto tantalum nitride barrier layers before electroplating copper in the forward pulsed mode. The Cu seed layer was cleaned by plasma H 2 and N 2 prior to electroplating a copper film. Cu films electroplated on the copper seed layer with plasma pretreatment showed better electrical and physical properties such as electrical resistivities, surface morphologies, levels of impurities, adhesion and surface roughness than those without plasma pretreatment. It is shown that carbon and metal oxide contaminants at the sputtered Cu seed/TaN surface could be effectively removed by plasma H 2 cleaning. The degree of the (111) prefered orientation of the Cu film with plasma H 2 pretreatment is as high as pulse plated Cu film without plasma pretreatment. Also, plasma H 2 precleaning is more effective in enhancing the Cu electroplating properties onto the Cu seed layer than plasma N 2 precleaning
Growth, characterization and electrochemical properties of hierarchical CuO nanostructures for supercapacitor applications

Energy Technology Data Exchange (ETDEWEB)

Krishnamoorthy, Karthikeyan [Nanomaterials and System Laboratory, Department of Mechanical Engineering, Jeju National University, Jeju 690 756 (Korea, Republic of); Kim, Sang-Jae, E-mail: kimsangj@jejunu.ac.kr [Nanomaterials and System Laboratory, Department of Mechanical Engineering, Jeju National University, Jeju 690 756 (Korea, Republic of); Department of Mechatronics Engineering, Jeju National University, Jeju 690 756 (Korea, Republic of)

2013-09-01

Graphical abstract: - Highlights: • Hierarchical CuO nanostructures were grown on Cu foil. • Monoclinic phase of CuO was grown. • XPS analysis revealed the presence of Cu(2p{sub 3/2}) and Cu(2p{sub 1/2}) on the surfaces. • Specific capacitance of 94 F/g was achieved for the CuO using cyclic voltammetry. • Impedance spectra show their pseudo capacitor applications. - Abstract: In this paper, we have investigated the electrochemical properties of hierarchical CuO nanostructures for pseudo-supercapacitor device applications. Moreover, the CuO nanostructures were formed on Cu substrate by in situ crystallization process. The as-grown CuO nanostructures were characterized using X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FT-IR), X-ray photoelectron spectroscopy and field emission-scanning electron microscope (FE-SEM) analysis. The XRD and FT-IR analysis confirm the formation of monoclinic CuO nanostructures. FE-SEM analysis shows the formation of leave like hierarchical structures of CuO with high uniformity and controlled density. The electrochemical analysis such as cyclic voltammetry and electrochemical impedance spectroscopy studies confirms the pseudo-capacitive behavior of the CuO nanostructures. Our experimental results suggest that CuO nanostructures will create promising applications of CuO toward pseudo-supercapacitors.
Growth, characterization and electrochemical properties of hierarchical CuO nanostructures for supercapacitor applications

International Nuclear Information System (INIS)

Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

2013-01-01

Graphical abstract: - Highlights: • Hierarchical CuO nanostructures were grown on Cu foil. • Monoclinic phase of CuO was grown. • XPS analysis revealed the presence of Cu(2p 3/2 ) and Cu(2p 1/2 ) on the surfaces. • Specific capacitance of 94 F/g was achieved for the CuO using cyclic voltammetry. • Impedance spectra show their pseudo capacitor applications. - Abstract: In this paper, we have investigated the electrochemical properties of hierarchical CuO nanostructures for pseudo-supercapacitor device applications. Moreover, the CuO nanostructures were formed on Cu substrate by in situ crystallization process. The as-grown CuO nanostructures were characterized using X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FT-IR), X-ray photoelectron spectroscopy and field emission-scanning electron microscope (FE-SEM) analysis. The XRD and FT-IR analysis confirm the formation of monoclinic CuO nanostructures. FE-SEM analysis shows the formation of leave like hierarchical structures of CuO with high uniformity and controlled density. The electrochemical analysis such as cyclic voltammetry and electrochemical impedance spectroscopy studies confirms the pseudo-capacitive behavior of the CuO nanostructures. Our experimental results suggest that CuO nanostructures will create promising applications of CuO toward pseudo-supercapacitors
Room Temperature Radiolytic Synthesized Cu@CuAlO₂-Al₂O₃ Nanoparticles

Directory of Open Access Journals (Sweden)

Nayereh Soltani

2012-09-01

Full Text Available Colloidal Cu@CuAlO₂-Al₂O₃ bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a ⁶⁰Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO₂-Al₂O₃ nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM, energy dispersive X-ray spectrometry (EDX, and X-ray diffraction (XRD showed that Cu@CuAlO₂-Al₂O₃ nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation.
Approaching the limit of Cu(II)/Cu(I) mixed valency in a Cu(I)Br2-N-methylquinoxalinium hybrid compound.

Science.gov (United States)

Leblanc, Nicolas; Sproules, Stephen; Pasquier, Claude; Auban-Senzier, Pascale; Raffy, Helene; Powell, Annie K

2015-08-18

A novel 1D hybrid salt (MQ)[CuBr2]∞ (MQ = N-methylquinoxalinium) is reported. Structural, spectroscopic and magnetic investigations reveal a minimal Cu(II) doping of less than 0.1%. However it is not possible to distinguish Cu(I) and Cu(II). The unusually close packing of the organic moieties and the dark brown colour of the crystals suggest a defect electronic structure.
Nucleation and Growth of Cu-Al Intermetallics in Al-Modified Sn-Cu and Sn-Ag-Cu Lead-Free Solder Alloys

Science.gov (United States)

Reeve, Kathlene N.; Anderson, Iver E.; Handwerker, Carol A.

2015-03-01

Lead-free solder alloys Sn-Cu (SC) and Sn-Ag-Cu (SAC) are widely used by the microelectronics industry, but enhanced control of the microstructure is needed to improve solder performance. For such control, nucleation and stability of Cu-Al intermetallic compound (IMC) solidification catalysts were investigated by variation of the Cu (0.7-3.0 wt.%) and Al (0.0-0.4 wt.%) content of SC + Al and SAC + Al alloys, and of SAC + Al ball-grid array (BGA) solder joints. All of the Al-modified alloys produced Cu-Al IMC particles with different morphologies and phases (occasionally non-equilibrium phases). A trend of increasing Cu-Al IMC volume fraction with increasing Al content was established. Because of solidification of non-equilibrium phases in wire alloy structures, differential scanning calorimetry (DSC) experiments revealed delayed, non-equilibrium melting at high temperatures related to quenched-in Cu-Al phases; a final liquidus of 960-1200°C was recorded. During cooling from 1200°C, the DSC samples had the solidification behavior expected from thermodynamic equilibrium calculations. Solidification of the ternary alloys commenced with formation of ternary β and Cu-Al δ phases at 450-550°C; this was followed by β-Sn, and, finally, Cu6Sn5 and Cu-Al γ1. Because of the presence of the retained, high-temperature phases in the alloys, particle size and volume fraction of the room temperature Cu-Al IMC phases were observed to increase when the alloy casting temperature was reduced from 1200°C to 800°C, even though both temperatures are above the calculated liquidus temperature of the alloys. Preliminary electron backscatter diffraction results seemed to show Sn grain refinement in the SAC + Al BGA alloy.
Explanation of the photocurrent quantum efficiency (Φ) enhancements through the CAN's model equation for the p-CuI sensitized methylviolet-C18 LB films in the photoelectrochemical cells (PECs) and Cu/n-Cu2O/M-C18/p-CuI solid-state photovoltaic cells

International Nuclear Information System (INIS)

Fernando, C A N; Liyanaarachchi, U S; AARajapaksha, R D

2013-01-01

Photocurrent enhancements in a dye sensitized photoelectrochemical cell (PEC) with a Cu/p-CuI/M-C 18 photoelectrode and a dye sensitized solid state photovoltaic cell (DSSC) with Cu/n-Cu 2 O/M-C 18 /p-CuI are studied by controlling the formation of dye aggregates of M-C 18 Langmuir–Blodgett (LB) films on the p-CuI layer. LB films of M-C 18 are deposited under biasing conditions during the LB deposition process on Cu/p-CuI, Cu/n-Cu 2 O/p-CuI and conductive glass plates with the three-electrode configuration setup coupling to the LB trough. LB films prepared under positive biasing conditions enhance the photocurrent quantum efficiencies for both PECs and DSSCs controlling and minimizing the formation of dye aggregates. The electrolyte used for LB deposition and photocurrent measurements is (10 −2 M) Fe 2+ + Fe 3+ (10 −2 M) and (10 −2 M) NaH 2 PO 4 –Na 2 HPO 4 , pH = 6 buffer solution. Maximum photocurrent quantum efficiencies (φmax%) obtained are ≈22% for PEC and ≈20% for DSSCs, where the M-C 18 LB film deposition applied potentials +0.3 V versus Ag/AgCl. The mechanism of the photocurrent enhancement is discussed through the CAN's model equation, φ = AD 0 –BD 0 2 , where A = k 1 k 2 /F, B = I k 1 2 k 2 [2k 6 /F 3 + k 2 k 4 /k 3 2 X 2 F 2 ], F = k 2 + k 5 Y + k 7 + k 1 I [1 + k 2 /k 3 X], presented from our previous study [1]. Experimental evidence for the formation of the aggregates of M-C 18 LB films for the negative applied potentials and suppression of the aggregates with positive applied potentials are presented from absorption spectra, AFM pictures and fluorescence measurements of the samples. Conversion efficiency obtained is ≈2.5%, V oc ≈750 mV and I sc ≈ 5.8 mA cm −2 for DSSC fabricated with +0.3 V versus Ag/AgCl applied deposition potential of M-C 18 LB films. (paper)
Explanation of the photocurrent quantum efficiency (Φ) enhancements through the CAN's model equation for the p-CuI sensitized methylviolet-C18 LB films in the photoelectrochemical cells (PECs) and Cu/n-Cu2O/M-C18/p-CuI solid-state photovoltaic cells

Science.gov (United States)

Fernando, C. A. N.; Liyanaarachchi, U. S.; AARajapaksha, R. D.

2013-04-01

Photocurrent enhancements in a dye sensitized photoelectrochemical cell (PEC) with a Cu/p-CuI/M-C18 photoelectrode and a dye sensitized solid state photovoltaic cell (DSSC) with Cu/n-Cu2O/M-C18/p-CuI are studied by controlling the formation of dye aggregates of M-C18 Langmuir-Blodgett (LB) films on the p-CuI layer. LB films of M-C18 are deposited under biasing conditions during the LB deposition process on Cu/p-CuI, Cu/n-Cu2O/p-CuI and conductive glass plates with the three-electrode configuration setup coupling to the LB trough. LB films prepared under positive biasing conditions enhance the photocurrent quantum efficiencies for both PECs and DSSCs controlling and minimizing the formation of dye aggregates. The electrolyte used for LB deposition and photocurrent measurements is (10-2 M) Fe2+ + Fe3+ (10-2 M) and (10-2 M) NaH2PO4-Na2HPO4, pH = 6 buffer solution. Maximum photocurrent quantum efficiencies (Фmax%) obtained are ≈22% for PEC and ≈20% for DSSCs, where the M-C18 LB film deposition applied potentials +0.3 V versus Ag/AgCl. The mechanism of the photocurrent enhancement is discussed through the CAN's model equation, Ф = AD0-BD02, where A = k1k2/F, B = I k12 k2[2k6/F3 + k2k4/k32 X2F2], F = k2 + k5Y + k7 + k1 I [1 + k2/k3 X], presented from our previous study [1]. Experimental evidence for the formation of the aggregates of M-C18 LB films for the negative applied potentials and suppression of the aggregates with positive applied potentials are presented from absorption spectra, AFM pictures and fluorescence measurements of the samples. Conversion efficiency obtained is ≈2.5%, Voc ≈750 mV and Isc ≈ 5.8 mA cm-2 for DSSC fabricated with +0.3 V versus Ag/AgCl applied deposition potential of M-C18 LB films.
Analysis of process parameters in the laser deposition of YBa{sub 2}Cu{sub 3}O{sub 7} superconducting films by using SVR

Energy Technology Data Exchange (ETDEWEB)

Cai, C.Z., E-mail: caiczh@gmail.com [Department of Applied Physics, Chongqing University, Chongqing 401331 (China); Xiao, T.T. [Department of Applied Physics, Chongqing University, Chongqing 401331 (China); Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, CAEP, P.O. Box 919-988, Mianyang 621900 (China); Tang, J.L.; Huang, S.J. [Department of Applied Physics, Chongqing University, Chongqing 401331 (China)

2013-10-15

Highlights: • Proposed new ideas and strategies to improve energy storage density for SMES system. • One is to increase the effective current density in the superconducting coils. • Another is to optimize the configuration of the SMES coil. • A new conceive of energy compression is also proposed. -- Abstract: There are several process parameters in the growth of YBa{sub 2}Cu{sub 3}O{sub 7} superconducting films by using pulsed laser deposition (PLD). The relationship between the response and process parameters is highly nonlinear and quite complicated. It is very valuable to quantitatively estimate the response under different deposition parameters. In this study, according to an experimental data set on the superconducting transition temperature (T{sub c}) and relative resistance ratio (r{sub R}) of 17 samples of YBa{sub 2}Cu{sub 3}O{sub 7} films deposited under various parameters, the support vector regression (SVR) combined with particle swarm optimization (PSO), was proposed to predict the T{sub c} and r{sub R} for YBa{sub 2}Cu{sub 3}O{sub 7} films. The prediction performance of SVR was compared with that of multiple regression analysis (MRA) models. The results strongly support that the generalization ability of SVR model consistently surpasses that of MRA via leave-one-out cross validation (LOOCV). The mean absolute percentage errors for T{sub c} and r{sub R} are 0.37% and 1.51% respectively via LOOCV test of SVR. Sensitivity analysis discovered the most sensitive parameters affecting the T{sub c} and r{sub R}. This study suggests that the established SVR model can be used to accurately foresee the T{sub c} and r{sub R}. And it can be used to optimizing the deposition parameters in the development of YBa{sub 2}Cu{sub 3}O{sub 7} films via PLD.
High-temperature stability of Au/Pd/Cu and Au/Pd(P)/Cu surface finishes

Science.gov (United States)

Ho, C. E.; Hsieh, W. Z.; Lee, P. T.; Huang, Y. H.; Kuo, T. T.

2018-03-01

Thermal reliability of Au/Pd/Cu and Au/Pd(4-6 wt.% P)/Cu trilayers in the isothermal annealing at 180 °C were investigated by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and transmission electron microscopy (TEM). The pure Pd film possessed a nanocrystalline structure with numerous grain boundaries, thereby facilitating the interdiffusion between Au and Cu. Out-diffusion of Cu through Pd and Au grain boundaries yielded a significant amount of Cu oxides (CuO and Cu2O) over the Au surface and gave rise to void formation in the Cu film. By contrast, the Pd(P) film was amorphous and served as a good diffusion barrier against Cu diffusion. The results of this study indicated that amorphous Pd(P) possessed better oxidation resistance and thermal reliability than crystalline Pd.
Computer simulation of the structure of liquid metal halides RbBr, CuCl, CuBr, CuI, and AgBr

International Nuclear Information System (INIS)

Belashchenko, D.K.; Ostrovskij, O.I.

2003-01-01

The computerized models of the RbBr, AgBr, CuCl, CuBr and CuI liquid ion systems of 498 ions dimension are simulated at the temperatures of 753-960 K on the basis of the known diffraction data through the BELION algorithm. Good agreement of diffraction and model partial pair correlation functions (PPCF), excluding the PPCF first peaks heights, is obtained in all the cases. The simulation is carried out by the varied ion charges (the atomization energy values, close to the real ones, are obtained by ion charges ±1.00 for the RbBr, ±1.15 for AgBr, ±1.20 for CuCl, ±1.48 for CuBr and ±1.367 for CuI). The noncoulomb contributions in the interparticle potentials are calculated [ru

Biosorption of Cu(II) onto agricultural materials from tropical regions

KAUST Repository

Acheampong, Mike A.

2011-04-26

Background: In Ghana, the discharge of untreated gold mine wastewater contaminates the aquatic systems with heavy metals such as copper (Cu), threatening ecosystem and human health. The undesirable effects of these pollutants can be avoided by treatment of the mining wastewater prior to discharge. In this work, the sorption properties of agricultural materials, namely coconut shell, coconut husk, sawdust and Moringa oleifera seeds for Cu(II) were investigated. Results: The Freundlich isotherm model described the Cu(II) removal by coconut husk (R2 = 0.999) and sawdust (R2 = 0.993) very well and the Cu(II) removal by Moringa oleifera seeds (R2 = 0.960) well. The model only reasonably described the Cu(II) removal by coconut shell (R2 = 0.932). A maximum Cu(II) uptake of 53.9 mg g-1 was achieved using the coconut shell. The sorption of Cu(II) onto coconut shell followed pseudo-second-order kinetics (R2 = 0.997). FTIR spectroscopy indicated the presence of functional groups in the biosorbents, some of which were involved in the sorption process. SEM-EDX analysis confirmed an exchange of Mg(II) and K(I) for Cu(II) on Moringa oleifera seeds and K(I) for Cu(II) on coconut shell. Conclusion: This study shows that coconut shell can be an important low-cost biosorbent for Cu(II) removal. The results indicate that ion exchange, precipitation and electrostatic forces were involved in the Cu(II) removal by the biosorbents investigated. © 2011 Society of Chemical Industry.
Species dependence of [64Cu]Cu-Bis(thiosemicarbazone) radiopharmaceutical binding to serum albumins

International Nuclear Information System (INIS)

Basken, Nathan E.; Mathias, Carla J.; Lipka, Alexander E.; Green, Mark A.

2008-01-01

Introduction: Interactions of three copper(II) bis(thiosemicarbazone) positron emission tomography radiopharmaceuticals with human serum albumin, and the serum albumins of four additional mammalian species, were evaluated. Methods: 64 Cu-labeled diacetyl bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-ATSM), pyruvaldehyde bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-PTSM) and ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) were synthesized and their binding to human, canine, rat, baboon and porcine serum albumins quantified by ultrafiltration. Protein binding was also measured for each tracer in human, porcine, rat and mouse serum. Results: The interaction of these neutral, lipophilic copper chelates with serum albumin is highly compound- and species-dependent. Cu-PTSM and Cu-ATSM exhibit particularly high affinity for human serum albumin (HSA), while the albumin binding of Cu-ETS is relatively insensitive to species. At HSA concentrations of 40 mg/ml, '% free' (non-albumin-bound) levels of radiopharmaceutical were 4.0±0.1%, 5.3±0.2% and 38.6±0.8% for Cu-PTSM, Cu-ATSM and Cu-ETS, respectively. Conclusions: Species-dependent variations in radiopharmaceutical binding to serum albumin may need to be considered when using animal models to predict the distribution and kinetics of these compounds in humans
The activation energy for loop growth in Cu and Cu-Ni alloys

International Nuclear Information System (INIS)

Barlow, P.; Leffers, T.; Singh, B.N.

1978-08-01

The apparent activation energy for the growth of interstitial dislocation loops in copper, Cu-1%Ni, Cu-2%Ni, and Cu-5%Ni during high voltage electron microscope irradiation was determined. The apparent activation energy for loop growth in all these materials can be taken to be 0.34eV+-0.02eV. This value together with the corresponding value of 0.44eV+-0.02eV determined earlier for Cu-10%Ni is discussed with reference to the void growth rates observed in these materials. The apparent activation energy for loop growth in copper (and in Cu-1%Ni that has a void growth rate similar to that in pure copper) is interpreted as twice the vacancy migration energy (indicating that divacancies do not play any significant role). For the materials with higher Ni content (in which the void growth rate is much lower than that in Cu and Cu-1%Ni) the measured apparent activation energy is interpreted to be characteristic of loops positioned fairly close to the foil surface and not of loops in ''bulk material''. From the present results in combination with the earlier results for Cu-10%Ni it is concluded that interstitial trapping is the most likely explanation of the reduced void growth rate in Cu-Ni alloys. (author)
Comparison of stress-induced voiding phenomena in copper line–via structures with different dielectric materials

International Nuclear Information System (INIS)

Hou, Yuejin; Tan, Cher Ming

2009-01-01

The package level stress-induced voiding (SIV) test of Cu dual-damascene line–via structures is performed. Two different dielectrics, undoped silica glass (USG) and carbon doped oxide (CDO), are used in this work. After 1344 h of high temperature storage test, the resistance drift of USG interconnects is found to be much smaller than that of CDO interconnects and voids are located at the bottom of the via for both USG and CDO interconnects. However, horizontal voids grown along the via bottom is observed for USG interconnects, whilst voids are found to grow vertically along the via sidewall for CDO interconnects. The phenomena are explained using finite element analysis in this work, and the observed poor SIV performance for CDO interconnects is also explained. With this finite element analysis, the implications of different low-k dielectrics on SIV reliability are discussed
Record critical current densities in IG processed bulk YBa{sub 2}Cu{sub 3}O{sub y} fabricated using ball-milled Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} phase

Energy Technology Data Exchange (ETDEWEB)

Muralidhar, Miryala; Kenta, Nakazato; Murakami, Masato [Department of Materials Science and Engineering, Superconducting Materials Laboratory, Shibaura Institute of Technology, Tokyo (Japan); Zeng, XianLin; Koblischka, Michael R. [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany); Diko, Pavel [Institute of Experimental Physics, Material Physics Laboratory, Slovak Academy of Sciences, Kosice (Slovakia)

2016-02-15

The infiltration-growth (IG) technique enables the uniform and controllable Y{sub 2}BaCuO{sub 5} (Y211) secondary phase particles formation within the YBa{sub 2}Cu{sub 3}O{sub y} (Y123) matrix. Recent results clarified that the flux pinning performance of the Y123 material was dramatically improved by optimizing the processing conditions during the IG process. In this paper, we adapted the IG technique and produced several samples with addition of nanometer-sized Y211 secondary phase particles, which were produced by a ball milling technique. We found that the performance of the IG processed Y123 material dramatically improved in the low field region for a ball milling time of 12 h as compared to the samples without a ball milling step. Magnetization measurements showed a sharp superconducting transition with an onset T{sub c} at around 92 K. The critical current density (J{sub c}) at 77 K and zero field was determined to be 224 022 Acm{sup -2}, which is higher than the not ball-milled sample. Furthermore, microstructural observations exhibited a uniform microstructure with homogenous distribution of nanosized Y-211 inclusions within the Y-123 matrix. The improved performance of the Y-123 material can be understood in terms of fine distribution of the secondary phases. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Effects of hydrazine on the solvothermal synthesis of Cu{sub 2}ZnSnSe{sub 4} and Cu{sub 2}CdSnSe{sub 4} nanocrystals for particle-based deposition of films

Energy Technology Data Exchange (ETDEWEB)

Chiang, Ming-Hung [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Fu, Yaw-Shyan, E-mail: ysfu@mail.nutn.edu.tw [Department of Greenergy, National University of Tainan, Tainan, Taiwan 700 (China); Shih, Cheng-Hung; Kuo, Chun-Cheng [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Guo, Tzung-Fang [Department of Photonics, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan 701 (China); Lin, Wen-Tai, E-mail: wtlin@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China)

2013-10-01

The effects of hydrazine on the synthesis of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) and Cu{sub 2}CdSnSe{sub 4} (CCTSe) nanocrystals in an autoclave as a function of temperature and time were explored. On heating at 190 °C for 24-72 h, pure CZTSe and CCTSe nanocrystals could readily grow in the hydrazine-added solution, while in the hydrazine-free solution the intermediate phases such as ZnSe, Cu{sub 2}Se, and Cu{sub 2}SnSe{sub 3}, and Cu{sub 2}SnSe{sub 3} and CdSe associated with the CZTSe and CCTSe nanocrystals grew, respectively. This result reveals that hydrazine can speed up the synthesis of pure CZTSe and CCTSe nanocrystals via a solvothermal process. The mechanisms for the hydrazine-enhanced growth of CZTSe and CCTSe nanocrystals were discussed. The pure CZTSe and CCTSe nanocrystals were subsequently fabricated to the smooth films by spin coating without further annealing in selenium atmosphere. This processing may be beneficial to the fabrication of the absorber layer for solar cells and thermoelectric devices. - Highlights: • Hydrazine enhances the growth of pure Cu{sub 2}ZnSnSe{sub 4} and Cu{sub 2}CdSnSe{sub 4} nanocrystals. • The nanocrystals can be fabricated to films by spin coating without annealing. • This solvothermal processing is promising for the fabrication of thin film devices.
Investigation of different ethylenediamine-N,N'-disuccinic acid-enhanced washing configurations for remediation of a Cu-contaminated soil: process kinetics and efficiency comparison between single-stage and multi-stage configurations.

Science.gov (United States)

Ferraro, Alberto; Fabbricino, Massimiliano; van Hullebusch, Eric D; Esposito, Giovanni

2017-09-01

A comparison of Cu extraction yields for three different ethylenediamine-N,N'-disuccinic acid (EDDS)-enhanced washing configurations was performed on a Cu-contaminated soil. Batch experiments were used to simulate a single-stage continuous stirred tank reactor (CSTR) and a multi-stage (side feeding and counter-current) reactor. Single-stage CSTR conditions were simulated for various EDDS:(Cu + Cd + Pb + Co + Ni + Zn) molar ratio (EDDS:M ratio) (from 1 to 30) and liquid to soil (L/S) ratio (from 15 to 45). The highest Cu extraction yield (≃56%) was achieved with EDDS:M = 30. In contrast, a Cu extraction yield decrease was observed with increasing L/S ratio with highest extracted Cu achievement (≃48%) for L/S = 15. Side feeding configuration was tested in four experimental conditions through different fractionation mode of EDDS dose and treatment time at each washing step. Results from the four tests showed all enhanced Cu extraction (maximum values from ≃43 to ≃51%) achieved at lower treatment time and lower EDDS:M molar ratio compared to CSTR configuration with L/S = 25 and EDDS:M = 10. The counter-current washing was carried out through two washing flows achieving a process performance enhancement with 27% increase of extracted Cu compared to single-stage CSTR configuration. Higher Cu extraction percentage (36.8%) was observed in the first washing phase than in the second one (24.7%).
The relationship of structure to superconductivity in the Pr-Ba-Cu-O system

Science.gov (United States)

Minseo, P.

1994-05-01

The relation of structure to lack of superconductivity in Pr-Ba-Cu-O was systematically investigated. First, the phase equilibria of this system was studied to find the processing parameters which maximize the cation-site ordering between Pr and Ba ions. Second, a comparative study between superconducting Nd-Ba-Cu-O and nonsuperconducting Pr-Ba-Cu-O was performed by forming solid-solution Nd-Pr-Ba-Cu-O. The relation between structure and superconductivity in Nd(1-x)Pr(x)Ba2Cu3O(7-delta) is investigated. T sub c decreases monotonically with increasing x and superconductivity disappears at around x = 0.3 to 0.4. T sub c is enhanced by 10 K when the sample is processed at an oxygen partial pressure (PO2) of 0.01 atm, followed by oxygenation at 450 C. Depression of T sub c as a function of x and PO2 is explained in terms of a charge-transfer model. It is suggested that destruction of superconductivity in the RE(1-x)Pr(x)Ba2Cu3O(7-delta) (RE=rare-earth) system can be viewed as disruption of four-fold planar coordinated Cu ions in the chain-site due to permanent occupation of extra Pr ions on Ba sites.
Giant Cu 2p Resonances in CuO Valence-Band Photoemission

NARCIS (Netherlands)

Tjeng, L.H.; Chen, C.T.; Ghijsen, J.; Rudolf, P.; Sette, F.

1991-01-01

We report the observation of a giant resonance in the Cu 2p resonant-photoemission spectra of CuO. The study allows the unambiguous identification of the local Cu 3d8 configuration in the valence-band photoemission spectrum, providing conclusive evidence for the charge-transfer nature of the
Diffusion of Cu+ in β-phase CuI

International Nuclear Information System (INIS)

Johansson, J.X.M.Z.; Skoeld, K.; Joergensen, J.E.

1992-01-01

Measurements of ionic diffusion of Cu + in solid CuI in the β-phase is carried out with a non-destructive radioactive tracer technique, utilizing coincidence counting of the annihilation gammas from the positron decay of 64 Cu. The diffusion coefficient and the activation energy for the diffusion are evaluated. The experimental results show distinct diffusion character in the β-phase which differs from those in the γ- and α-phases. The β-phase diffusion properties together with the previous results for γ-and α-phases will provide valuable guidance for MD calculations, in which the diffusion coefficients and activation energies have been overestimated and the γ-β phase transition does not appear. The ionic conductivity of CuI estimated from tracer diffusion results and the Nernst-Einstein relation are compared with values from electro-chemical methods. In all three phases the conductivities obtained from electro-chemical methods are much lower than those calculated from the measured tracer diffusion coefficients. (author). 7 refs.; 4 figs.; 2 tabs
Crystallization-mediated amorphous Cu{sub x}O (x = 1, 2)/crystalline CuI p–p type heterojunctions with visible light enhanced and ultraviolet light restrained photocatalytic dye degradation performance

Energy Technology Data Exchange (ETDEWEB)

Wang, Hongli; Cai, Yun; Zhou, Jian; Fang, Jun, E-mail: fangjun@njtech.edu.cn; Yang, Yang, E-mail: yangy@njtech.edu.cn

2017-04-30

Highlights: • Cu{sub x}O(x = 1, 2)/CuI p–p type heterojunctions were facilely constructed via crystallization-mediated approaches. • Cu{sub x}O/CuI heterojunctions exhibit effective visible-light-driven photocatalytic activity for dye degradation. • The Cu{sub x}O/CuI interface can enhance the spatial separation of the photogenerated electron–hole pairs. • This work represents a critical step for mass production of functional semiconductor heterojunctions in a mild manner. - Abstract: We report simple and cost-effective fabrication of amorphous Cu{sub x}O (x = 1, 2)/crystalline CuI p–p type heterojunctions based on crystallization-mediated approaches including antisolvent crystallization and crystal reconstruction. Starting from CuI acetonitrile solution, large crystals in commercial CuI can be easily converted to aggregates consisting of small particles by the crystallization processes while the spontaneous oxidation of CuI by atmospheric/dissolved oxygen can induce the formation of trace Cu{sub x}O on CuI surface. As a proof of concept, the as-fabricated Cu{sub x}O/CuI heterojunctions exhibit effective photocatalytic activity towards the degradation of methyl blue and other organic pollutants under visible light irradiation, although the wide band-gap semiconductor CuI is insensible to visible light. Unexpectedly, the Cu{sub x}O/CuI heterojunctions exhibit restrained photocatalytic activity when ultraviolet light is applied in addition to the visible. It is suggested that the Cu{sub x}O/CuI interface can enhance the spatial separation of the electron–hole pairs with the excitation of Cu{sub x}O under visible light and prolong the lifetime of photogenerated charges with high redox ability. The present work represents a critically important step in advancing the crystallization technique for potential mass production of semiconductor heterojunctions in a mild manner.
In situ resistance measurements of bronze process Nb-Sn-Cu-Ta multifilamentary composite conductors during reactive diffusion

International Nuclear Information System (INIS)

Tan, K S; Hopkins, S C; Glowacki, B A; Majoros, M; Astill, D

2004-01-01

The conditions under which the Nb 3 Sn intermetallic layer is formed by solid-state reactive diffusion processes in bronze process multifilamentary conductors greatly influence the performance of the conductors. By convention, isothermal heat treatment is used and often causes non-uniformity of A15 layers formed across the wire. Therefore, characterization and optimization of the conductor during the reactive diffusion processes is crucial in order to improve the overall conductor's performance. In this paper, a different characterization approach and perhaps an optimization technique is presented, namely in situ resistance measurement by an alternating current (AC) method. By treating the components of such multifilamentary wires as a set of parallel resistors, the resistances of the components may be combined using the usual rules for resistors in parallel. The results show that the resistivity of the entire wire changes significantly during the reactive diffusion processes. The development of the Nb 3 Sn layer in bronze process Nb-Sn-Cu-Ta multifilamentary wires at different stages of the reactive diffusion processes has been monitored using measured resistivity changes, and correlated with results from DTA, ACS, SEM and EDS
Specific activity measurement of 64Cu: A comparison of methods

International Nuclear Information System (INIS)

Mastren, Tara; Guthrie, James; Eisenbeis, Paul; Voller, Tom; Mebrahtu, Efrem; Robertson, J. David; Lapi, Suzanne E.

2014-01-01

Effective specific activity of 64 Cu (amount of radioactivity per µmol metal) is important in order to determine purity of a particular 64 Cu lot and to assist in optimization of the purification process. Metal impurities can affect effective specific activity and therefore it is important to have a simple method that can measure trace amounts of metals. This work shows that ion chromatography (IC) yields similar results to ICP mass spectrometry for copper, nickel and iron contaminants in 64 Cu production solutions. - Highlights: • Comparison of TETA titration, ICP mass spectrometry, and ion chromatography to measure specific activity. • Validates ion chromatography by using ICP mass spectrometry as the “gold standard”. • Shows different types and amounts of metal impurities present in 64 Cu
Effect of defect on the nonlinear and dielectric property of Ca(1–x)SrxCu3Ti4O12 ceramics synthesized by sol–gel process

International Nuclear Information System (INIS)

Li, Tao; Liu, Dewei; Dai, Haiyang; Xiang, Huiwen; Chen, Zhenping; He, Huifang; Chen, Zhiquan

2014-01-01

Highlights: • Ca (1−x) Sr x Cu 3 Ti 4 O 12 ceramics are synthesized by sol–gel process. • Positron annihilation lifetime spectra is used to investigate the defects of samples. • Nonlinear and dielectric properties are controlled by density and defects of samples. - Abstract: Ca (1−x) Sr x Cu 3 Ti 4 O 12 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.3 and 0.4) ceramics are synthesized by sol–gel process. The XRD patterns show that weak peaks of Sr 4 Ti 3 O 10 , TiO 2 and Ca 1.7 Sr 0.3 CuO 3 begin to appear at x ⩾ 0.2. Sr-doping is conductive to increase the density and reduce the defect concentration Ca (1−x) Sr x Cu 3 Ti 4 O 12 ceramics as x ⩽ 0.15. With increasing x (0.2 ⩽ x ⩽ 0.4), Sr-doping reduces the density and enhances the concentration of defects for the ceramics. The nonlinear coefficient value increases and reaches a maximum 13.5 at x = 0.15, and then decreases gradually with increasing x. The dielectric properties demonstrate that, as x ⩽ 0.15, Sr-doping not only increases the dielectric permittivity value and decreases the dielectric loss but also reduces the dependence on frequency at low frequencies. With increasing x (0.2 ⩽ x ⩽ 0.4), Sr-doping begins to lead to an inverse result in dielectric behaviors. The nonlinear and dielectric properties of Ca (1−x) Sr x Cu 3 Ti 4 O 12 ceramics are directly controlled by the density and defects
Soil solution dynamics of Cu and Zn in a Cu- and Zn-polluted soil as influenced by gamma-irradiation and Cu-Zn interaction.

Science.gov (United States)

Luo, Y M; Yan, W D; Christie, P

2001-01-01

A pot experiment was conducted to study soil solution dynamics of Cu and Zn in a Cu/Zn-polluted soil as influenced by gamma-irradiation and Cu-Zn interaction. A slightly acid sandy loam was amended with Cu and Zn (as nitrates) either singly or in combination (100 mg Cu and 150 mg Zn kg(-1) soil) and was then gamma-irradiated (10 kGy). Unamended and unirradiated controls were included, and spring barley (Hordeum vulgare L. cv. Forrester) was grown for 50 days. Soil solution samples obtained using soil moisture samplers immediately before transplantation and every ten days thereafter were used directly for determination of Cu, Zn, pH and absorbance at 360 nm (A360). Cu and Zn concentrations in the solution of metal-polluted soil changed with time and were affected by gamma-irradiation and metal interaction. gamma-Irradiation raised soil solution Cu substantially but generally decreased soil solution Zn. These trends were consistent with increased dissolved organic matter (A360) and solution pH after gamma-irradiation. Combined addition of Cu and Zn usually gave higher soil solution concentrations of Cu or Zn compared with single addition of Cu or Zn in gamma-irradiated and non-irradiated soils, indicating an interaction between Cu and Zn. Cu would have been organically complexed and consequently maintained a relatively high concentration in the soil solution under higher pH conditions. Zn tends to occur mainly as free ion forms in the soil solution and is therefore sensitive to changes in pH. The extent to which gamma-irradiation and metal interaction affected solubility and bioavailability of Cu and Zn was a function of time during plant growth. Studies on soil solution metal dynamics provide very useful information for understanding metal mobility and bioavailability.
Spin dynamics in CuO and Cu[sub 1[minus][ital x

Energy Technology Data Exchange (ETDEWEB)

Carretta, P.; Corti, M.; Rigamonti, A. (Department of Physics Alessandro Volta,' ' University of Pavia, Via Bassi 6, 27100 Pavia (Italy))

1993-08-01

[sup 63]Cu nuclear quadrupole resonance (NQR), nuclear antiferromagnetic resonance (AFNMR), and spin-lattice relaxation, as well as [sup 7]Li NMR and relaxation measurements in CuO and in Cu[sub 1[minus][ital x
Cu ion ink for a flexible substrate and highly conductive patterning by intensive pulsed light sintering.

Science.gov (United States)

Wang, Byung-Yong; Yoo, Tae-Hee; Song, Yong-Won; Lim, Dae-Soon; Oh, Young-Jei

2013-05-22

Direct printing techniques that utilize nanoparticles to mitigate environmental pollution and reduce the processing time of the routing and formation of electrodes have received much attention lately. In particular, copper (Cu) nanoink using Cu nanoparticles offers high conductivity and can be prepared at low cost. However, it is difficult to produce homogeneous nanoparticles and ensure good dispersion within the ink. Moreover, Cu particles require a sintering process over an extended time at a high temperature due to high melting temperature of Cu. During this process, the nanoparticles oxidize quickly in air. To address these problems, the authors developed a Cu ion ink that is free of Cu particles or any other impurities. It consequently does not require separate dispersion stability. In addition, the developed ink is environmentally friendly and can be sintered even at low temperatures. The Cu ion ink was sintered on a flexible substrate using intense pulsed light (IPL), which facilitates large-area, high-speed calcination at room temperature and at atmospheric pressures. As the applied light energy increases, the Cu2O phase diminishes, leaving only the Cu phase. This is attributed to the influence of formic acid (HCOOH) on the Cu ion ink. Only the Cu phase was observed above 40 J cm(-2). The Cu-patterned film after sintering showed outstanding electrical resistivity in a range of 3.21-5.27 μΩ·cm at an IPL energy of 40-60 J cm(-2). A spiral-type micropattern with a line width of 160 μm on a PI substrate was formed without line bulges or coffee ring effects. The electrical resistivity was 5.27 μΩ·cm at an energy level of 40.6 J cm(-2).
Novel CuCr_2O_4 embedded CuO nanocomposites for efficient photodegradation of organic dyes

International Nuclear Information System (INIS)

Mageshwari, K.; Sathyamoorthy, R.; Lee, Jeong Yong; Park, Jinsub

2015-01-01

Graphical abstract: - Highlights: • Novel CuO–CuCr_2O_4 nanocomposites synthesized by reflux condensation method. • Methyl orange and methylene blue dye degradation studied under UV light irradiation. • Nanocomposites characterized by XRD, FESEM, TEM, EDX, UV–vis DRS and PL. • CuCr_2O_4 loading effectively enhanced the catalytic activity of CuO. - Abstract: Novel photocatalyst based on CuO–CuCr_2O_4 nanocomposites was synthesized for different Cr"3"+ concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr_2O_4 as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr"3"+ in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO–CuCr_2O_4 nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr_2O_4 loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO–CuCr_2O_4 nanocomposites can be attributed to the presence of CuCr_2O_4 as an electron acceptor, which improves the effective charge separation in CuO.
Fabrication of Cu-riched W–Cu composites by combustion synthesis and melt-infiltration in ultrahigh-gravity field

Energy Technology Data Exchange (ETDEWEB)

Zhao, Pei [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Guo, Shibin; Liu, Guanghua; Chen, Yixiang [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Li, Jiangtao, E-mail: ljt0012@vip.sina.com [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2013-10-15

Unadulterated Cu-riched W–Cu composites of W27–Cu73, W34–Cu66, W40–Cu60, W49–Cu51 and W56–Cu44 have been prepared by a novel method called combustion synthesis and melt-infiltration in ultrahigh-gravity field, of which W27–Cu73 and W34–Cu66 showed good ductility and W40–Cu60, W49–Cu51 and W56–Cu44 were brittle. In this technique, Cu melt accompanied with a great amount of heat was produced by thermit reaction and infiltrated into W–Cu powder bed. When the powder bed was Cu-riched powder bed such as W50–Cu50 or W60–Cu40, Cu melt would go through the powder bed, reach the bottom of the graphite crucible and then form a heat dissipation channel. Thus the cooling rate was so fast that the product was mixed up with impurity. The problem can be solved by putting some W powders under W50–Cu50 or W60–Cu40 powder bed to prevent the formation of heat dissipation channel.
Specific Effects of Oxygen Molecule and Plasma on Thin-Film Growth of Y-Ba-Cu-O and Bi-Sr-(Ca)-Cu-O Systems

Science.gov (United States)

Endo, Tamio; Horie, Munehiro; Hirate, Naoki; Itoh, Katsutoshi; Yamada, Satoshi; Tada, Masaki; Itoh, Ken-ichi; Sugiyama, Morihiro; Sano, Shinji; Watabe, Kinji

1998-07-01

Thin films of a-oriented YBa2Cu3Ox (YBCO), Ca-doped c-oriented Bi2(Sr,Ca)2CuOx and nondoped c-oriented Bi2Sr2CuOx (Bi2201) were prepared at low temperatures by ion beam sputtering with supply of oxygen molecules or plasma. The plasma enhances crystal growth of the a-YBCO and Ca-doped Bi2201 phases. This can be interpreted in terms of their higher surface energies. The growth and quality of nondoped Bi2201 are improved with the supply of oxygen molecules. This particular result could be interpreted by the collision process between the oxygen molecules and the sputtered particles.

The influence of the addition of depleted uranium on particle pushing in melt-processed, bulk Y-Ba-Cu-O

International Nuclear Information System (INIS)

Diko, P; Zmorayova, K; Babu, N Hari; Krabbes, G; Cardwell, D A

2004-01-01

The microstructure of single-grain, melt-processed (MP) YBa 2 Cu 3 O 7 /Y 2 BaCuO 5 (Y-123/Y-211) samples (YBCO) containing varying amounts of depleted uranium (DU) and Pt has been studied. Only partial refinement of the Y-211 particle size was observed in Pt-free samples, which generally contained both small and large Y-211 particles. Small Y-211 particles in these samples are pushed extensively in the c-growth sector (c-GS) and all Y-211 particles (small and large) coarsen with the distance from the seed and with increasing DU concentration. Samples fabricated with Pt contained only very fine Y-211 particles, which were generally pushed strongly in the c-GS. In this case the size of the Y-211 particles did not vary significantly with distance from the seed. U- and U/Pt-containing sub-micron sized particles present in the melt-processed YBCO microstructure were not pushed during solidification, although their arrangement within the structure of the sample was influenced clearly by the growth process. The so-called cyclic growth was observed in the c-GS at the highest DU concentration (0.8 wt%). In these samples, this growth pattern is associated with the formation of a liquid phase rich in U and Y at the growth front. The cyclic growth mechanism was modified by the addition of Pt. Crystals of Y 2 Ba 4 UCuO x with Ba 3 YUO x phase inclusions were observed to be present in the U/Y-rich melt
Utilization of m-Phenylenediamine-Furfural Resin for Removal of Cu(II) from Aqueous Solution-A Thermodynamic Study

OpenAIRE

Najim, Tariq S.; Zainal, Israa G.; Ali, Dina A.

2010-01-01

m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The produced m-phenylenediamine-furfural resin was used for the removal of Cu(II) from aqueous solution. The pH for the optimum removal of Cu(II) was 6. The negative values of Gibbs free energy at low concentration of Cu(II) (20, 30 ppm) indicative of the spontaneous adsorption process, while, at higher Cu(II) concentration (40,50 ppm) the positive and weak values of ∆G° indicate that the process is fea...
Properties of the CuGaSe2 and CuInSe2 (001) surface

International Nuclear Information System (INIS)

Deniozou, T.

2005-01-01

The main task of this work was to investigate the (001) CuGaSe 2 and CuInSe 2 surface in dependence of preparation and stoichiometry. The knowledge of the atomic structure as well as other surface properties is important in respect to optimization of novel thin film solar cells. For the characterization of the layers mainly Auger electron Spectroscopy, low-energy electron diffraction and photoelectron spectroscopy were implemented. The development of an appropriate procedure with Ar + sputtering and annealing combined with decapping enabled the preparation of clean and well-ordered surfaces. Different surface structures were observed in dependence of the layer preparation and composition. A (4 x 1) reconstruction was observed for the first time on CuGaSe 2 layers grown with a moderate Cu-excess after preparation by sputtering and annealing. Similarly a (4 x 2) reconstruction was detected on CuInSe2 surfaces of Cu-poor layers. A reconstruction could be also observed on Cu-poorer layers, however the facets/steps could not be completely removed. Cu-richer layers were facet-free, however the observed reconstruction was also weaker. Thus it was shown that in contrary to recent expectations, according to which only the (112) surface is stable, also the (001) can be stable under particular conditions. The appearance of facets or steps is correlated with the presence of CuIn 3 Se 5 or CuGa 3 Se 5 phases. This information is furthermore important for the understanding of grain boundaries in polycrystalline CuGaSe 2 and CuInSe 2 . Binding energy shifts were observed for the first time on all Se3d, In4d, Ga3d, Cu3d core levels of the reconstructed surfaces. By comparison with results from the literature from the similar ZnSe (100) surface a modell for the (4 x 2) reconstruction was proposed. The surface components in the Se3d, In4d and Cu3d emission were attributed to Se dimers or In and Cu adatoms respectively. The x 1 periodicity of the (4 x 1) reconstruction of CuGaSe 2 is
Utilization of m-Phenylenediamine-Furfural Resin for Removal of Cu(II from Aqueous Solution-A Thermodynamic Study

Directory of Open Access Journals (Sweden)

Tariq S. Najim

2010-01-01

Full Text Available m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The produced m-phenylenediamine-furfural resin was used for the removal of Cu(II from aqueous solution. The pH for the optimum removal of Cu(II was 6. The negative values of Gibbs free energy at low concentration of Cu(II (20, 30 ppm indicative of the spontaneous adsorption process, while, at higher Cu(II concentration (40,50 ppm the positive and weak values of ∆G° indicate that the process is feasible but non spontaneous. The values of ∆H° were positive indicating that the sorption process is endothermic. On the other hand, the values of activation energy (Ea were inconsistent with the values of ∆H° both are positive and lie in the range of physisorption. The entropy ∆S° of the process was positive indicative of the randomness of the Cu(II ions at the solid / liquid interface. The values of sticking probability S* were less than one which indicate a preferable adsorption process and the mechanism is physisorption.
Layer growth and electronic defect properties of CuInS{sub 2} absorber layers from the sequence process; Schichtwachstum und elektronische Defekteigenschaften von CuInS{sub 2}-Absorberschichten aus dem sequentiellen Prozess

Energy Technology Data Exchange (ETDEWEB)

Siemer, K.

2000-10-01

The following topics were covered: synthesis of CuInS{sub 2} solar cells, layer growth of CuInS{sub 2} absorbers, electrical characterization, C-V and DLTS spectroscopy, defect spectroscopy of CuInS{sub 2} solar cells.
Stabilizing and Organizing Bi3 Cu4 and Bi7 Cu12 Nanoclusters in Two-Dimensional Metal-Organic Networks.

Science.gov (United States)

Yan, Linghao; Xia, Bowen; Zhang, Qiushi; Kuang, Guowen; Xu, Hu; Liu, Jun; Liu, Pei Nian; Lin, Nian

2018-04-16

Multinuclear heterometallic nanoclusters with controllable stoichiometry and structure are anticipated to possess promising catalytic, magnetic, and optical properties. Heterometallic nanoclusters with precise stoichiometry of Bi 3 Cu 4 and Bi 7 Cu 12 can be stabilized in the scaffold of two-dimensional metal-organic networks on a Cu(111) surface through on-surface metallosupramolecular self-assembly processes. The atomic structures of the nanoclusters were resolved using scanning tunneling microscopy and density functional theory calculations. The nanoclusters feature highly symmetric planar hexagonal shapes and core-shell charge modulation. The clusters are arranged as triangular lattices with a periodicity that can be tuned by choosing molecules of different size. This work shows that on-surface metallosupramolecular self-assembly creates unique possibilities for the design and synthesis of multinuclear heterometallic nanoclusters. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Hillock Formation, Metal Lifting and Voiding of an AlCu Metallization due to Temperature Treatment

International Nuclear Information System (INIS)

Foerster, J.; Schuderer, B.; Haeuser, M.; Kallensee, O.; Gross, Th.

2004-01-01

A metalstack with a layer composition of Ti/TiN/AlCu/TiN was evaluated in an AlCu metallization. Reliability results show a higher electromigration lifetime compared to a Ti/AlCu/Ti/TiN stack. During the metallization process flow large elevations were seen by optical inspection. Analysis by SEM cross sections showed different deviations. A metal lifting with void formation as consequence was found in large aluminum areas above tungsten plugs. Also voiding in the passivated Metal 2 and the unpassivated Metal 3 with a cracked anti-reflective coating as a result of the expansion of the aluminum was seen. The influence of processes with high thermal budget on the stress behaviour of the new metalstack was investigated. The final annealing was found as the process with the most critical influence. This study shows the influence of different final annealing temperatures on hillock formation and voiding using a Ti/TiN/AlCu/TiN metalstack. A reduction of the maximum temperature of the final annealing process is necessary for using the new AlCu metallization stack. The use of a surface treatment before deposition showed an optimization of the adhesion
Wear behavior of Cu-Ag-Cr alloy wire under electrical sliding

International Nuclear Information System (INIS)

Jia, S.G.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zheng, M.S.; Zhou, G.S.

2005-01-01

The wear behavior of a Cu-Ag-Cr alloy contact wire against a copper-base sintered alloy strip was investigated. Wear tests were conducted under laboratory conditions with a special sliding wear apparatus that simulated train motion under electrical current conditions. The initial microstructure of the Cu-Ag-Cr alloy contact wire was analyzed by transmission electron microscopy. Worn surfaces of the Cu-Ag-Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results indicate that the wear rate of the Cu-Ag-Cr wire increased with increasing electrical current and sliding. Within the studied range of electrical current, the wear rate increases with increasing electrical current and sliding speed. Compared with the Cu-Ag contact wire under the same testing conditions, the Cu-Ag-Cr alloy wire has much better wear resistance. Adhesive, abrasive, and electrical erosion wear are the dominant mechanisms during the electrical sliding processes
Mecano-synthesis of the alloy 25%Fe-50%Cu-25%Nb; Mecano-sintese da liga 25%Fe-50%Cu-25%Nb

Energy Technology Data Exchange (ETDEWEB)

Sousa, Keytiane; Oliveira, Michel Picanco de; Guimaraes, Renan da Silva; Moreira Junior, Valdenir; Filgueira, Marcello, E-mail: marcello.filgueira@pq.cnpq.br [Universidade Estadual do Norte Fluminense (CCT/LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil)

2016-07-01

In general, this study aims at the application of mechanical grinding to the system 25% Fe-50% Cu-25% Nb and studies the production process of these powders during milling. The evolution of the structure during the synthesis and the effect of variation of the grinding time were studied by diffraction of X-rays (XRD) and Scanning Electron Microscopy coupled EDS (SEM + EDS) in order to obtain the sizes of crystallites, the phase formation and its evolution with grinding time, and also the homogeneity of the mixture. The particle size distribution was analyzed by laser sedigraph technique. The powders synthesis were performed for milling time of 2.5, 5 and 10 hours. The mechanical grinding showed to be effective with the solid solution formation in the early grinding times. The XRD showed the solid solution formation with subsequent reduction and disappearance of Cu peaks. Through the technique of laser sedigraph it was observed the increase of the particle size followed by the its reduction in the milling time of 10h, a fact that characterizes the mechanical grinding process for ductile powder particles. Thus, the study demonstrated the effectiveness of the mechanical grinding to obtain powder of Fe-Cu-Nb and further processing and application of diamond cutting tools. (author)
Separations on a cellulose exchanger with salicylic acid as functional group. [Fe/sup 3//sup+//Cu/sup 2//sup+/, Cu/sup 2//sup+//Ni/sup 2//sup+//, and Cu/sup 2//sup+//Cu complex separations

Energy Technology Data Exchange (ETDEWEB)

Burba, P; Lieser, K H [Technische Hochschule Darmstadt (F.R. Germany). Fachbereich Anorganische Chemie und Kernchemie

1976-07-01

The use of a cellulose compound containing salicylic acid as functional group (capacity 0.6 mequ./g) for different problems is described. The seperations Fe/sup 3 +//Cu/sup 2 +/ and Cu/sup 2 +//Ni/sup 2 +/ in aqueous solutions are achieved smoothly at pH 2 and 2.5 resp. In organic solvents (pyridine) copper ions are separated from copper complexes as shown by the examples Cu/sup 2 +//(Cu(mnt)/sub 2/)/sup 2 -/ (mnt = maleonitril-1,2-dithiolate) and Cu/sup 2 +//dibenzo(b.i.)(5.9.14.18)tetraazacyclotetradecene-copper (Cu(chel)). The complex (Cu(mnt)/sub 2/)/sup 2 -/ can be labelled with Cu-64 on a separation column, whereas (Cu-(chel)) is substition inert.
Tracing contamination sources in soils with Cu and Zn isotopic ratios

Energy Technology Data Exchange (ETDEWEB)

Fekiacova, Z.; Cornu, S. [INRA, UR 1119 Géochimie des Sols et des Eaux, F-13100 Aix en Provence (France); Pichat, S. [Laboratoire de Géologie de Lyon (LGL-TPE), Ecole Normale Supérieure de Lyon, CNRS, UMR 5276, 69007 Lyon (France)

2015-06-01

Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ{sup 65}Cu values vary from − 0.15 to 0.44‰ and the δ{sup 66}Zn from − 0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from − 0.95 to 0.44‰ for δ{sup 65}Cu and from − 0.53 to 0.64‰ for δ{sup 66}Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. - Highlights: • Pedogenetic processes produce some Cu and Zn isotope fractionation. • Pollution with distinct isotopic signatures can be traced using Cu and Zn isotopes. • Tracing
Tracing contamination sources in soils with Cu and Zn isotopic ratios

International Nuclear Information System (INIS)

Fekiacova, Z.; Cornu, S.; Pichat, S.

2015-01-01

Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ 65 Cu values vary from − 0.15 to 0.44‰ and the δ 66 Zn from − 0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from − 0.95 to 0.44‰ for δ 65 Cu and from − 0.53 to 0.64‰ for δ 66 Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. - Highlights: • Pedogenetic processes produce some Cu and Zn isotope fractionation. • Pollution with distinct isotopic signatures can be traced using Cu and Zn isotopes. • Tracing of the metal
Observation of microwave conductivity in copper iodide films and relay effect in the dye molecules attached to CuI photocathode

International Nuclear Information System (INIS)

Sirimanne, Prasad M.; Soga, Tetsuo; Kunst, Marinus

2005-01-01

Microwave conductivity and two channels of recombination process were observed in the CuI films. Spin orbital splitting resulted in split in the valence band of CuI. The dye molecules attached to the CuI film act as an electron mediator in addition to the sensitization process under back wall-mode illumination. - Graphical abstract: Transient microwave-photoconductivity of CuI film
Density and superconducting properties of metal-sheathed YBa2Cu3Oy ceramic processed by hydrostatic extrusion

International Nuclear Information System (INIS)

Karpov, M.I.; Korzhov, V.P.; Artamoshin, A.V.; Prokopenko, V.M.

1994-01-01

Brittle materials can be deformed without cracking and rupturing using hydrostatic extrusion, which provides the greatest pore annihilation in powder-processed materials and allows large degrees of one-step deformation, which is favorable for texturing. Earlier, a casting slip prepared by mixing a starting powder of Y-based ceramic with an organic binder was conventionally extruded to produce a wire 150 μm in diameter. After special sintering, the critical-current density in the material attained a few hundred amperes per square centimeter at 77 K, and the wire could be rolled into a winding ≥0.3 m in diameter. Hydrostatic extrusion of an assembly composed of Y-based ceramic in a bimetallic Nb/Cu tube 30 mm in diameter was used to produce rods 6 mm in diameter; drawing of these rods yielded samples of wire 2 to 3 mm in diameter. It was shown that the extrusion pressure and strain substantially influence the yield of the rupture-free wire. No signs of rupturing, cracking, or necking were observed in wire extruded at pressures ≤700 MPa and degrees of deformation ≤50%. A pronounced instability of the hydrostatic extrusion, the appearance of defects, and even the rupture of the rods were caused by an increase in the pressure up to 2000 MPa and in the degree of one-step deformation up to 80%. In this work, the authors focus on the possibility of producing thin YBa 2 Cu 3 O y superconductors using only hydrostatic extrusion. They determined the parameters for the hydrostatic extrusion of the metal-sheathed YBa 2 Cu 3 O y ceramic to a diameter of 3 mm or to a rectangular cross section. Effects of the ceramic core, and of the reduction coefficient on superconducting-transition parameters and the critical-current density of the ceramic were examined
Continuous amorphization of Cu-Zr studied by positron lifetime

International Nuclear Information System (INIS)

Wilde, G.; Wuerschum, R.; Rabitsch, H.; Puff, W.

2006-01-01

Full text: Solid state amorphization by cold-rolling represents an attractive alternative to commonly used ball-milling. The present work aimed at a free volume study of the process of amorphization. To study the amorphization process binary Cu-Zr alloys were mechanically intermixed by cold rolling. Foils of pure Cu and Zr were stacked to form arrays of composition Cu 60 Zr 40 and folded four times. The folded samples were rolled at a strain rate of approximately 0.1 s -1 to a thickness of about 80 μm and then folded to double the thickness and rolled again to a minimum thickness of 80 μm. This procedure was repeated until the final material was cold-rolled for up to 80 passes. The microstructural changes during cold-rolling were investigated at different stages of the mechanical intermixing process by positron lifetime and 2-dimensional Doppler broadening measurements. The obtained Doppler results are discussed analysing the S-W-plot as well as a two-component fit and the shape of the ratio curves. Finally the results are compared to the lifetime results. (author)
Laser Photolytic Approach to Cu/polymer Sols and Cu/polymer Nanocomposites with Amorphous Cu Phase.

Czech Academy of Sciences Publication Activity Database

Pola, Josef; Ouchi, A.; Bakardjieva, Snejana; Urbanová, Markéta; Boháček, Jaroslav; Šubrt, Jan

2007-01-01

Roč. 192, 2-3 (2007) , s. 84-92 ISSN 1010-6030 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : Cu-polymer nanocomposite * laser solution photolysis * amorphous Cu phase Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 1.911, year: 2007
Electrolyte influence on the Cu nanoparticles electrodeposition onto boron doped diamond electrode

International Nuclear Information System (INIS)

Matsushima, Jorge Tadao; Santos, Laura Camila Diniz; Couto, Andrea Boldarini; Baldan, Mauricio Ribeiro; Ferreira, Neidenei Gomes

2012-01-01

This paper presents the electrolyte influence on deposition and dissolution processes of Cu nanoparticles on boron doped diamond electrodes (DDB). Morphological, structural and electrochemical analysis showed BDD films with good reproducibility, quality and reversible in a specific redox system. Electrodeposition of Cu nanoparticles on DDB electrodes in three different solutions was influenced by pH and ionic strength of the electrolytic medium. Analyzing the process as function of the scan rate, it was verified a better efficiency in 0,5 mol L -1 Na 2 SO 4 solution. Under the influence of the pH and ionic strength, Cu nanoparticles on DDB may be obtained with different morphologies and it was important for defining the desired properties. (author)
FTIR study of formic acid interaction with TiO2 and TiO2 doped with Pd and Cu in photocatalytic processes

International Nuclear Information System (INIS)

Arana, J.; Garriga i Cabo, C.; Dona-Rodriguez, J.M.; Gonzalez-Diaz, O.; Herrera-Melian, J.A.; Perez-Pena, J.

2004-01-01

In this study the different processes occurring on the TiO 2 and Pd and Cu doped TiO 2 surfaces during the photocatalytic formic acid degradation in the presence or absence of S 2 O 8 2- or H 2 O 2 have been investigated. FTIR studies have shown the relevance of the H-bounded hydroxyl groups. It has been observed that formate molecules interact simultaneously with the dopants and surfacial Ti atoms yielding an intermediate species which plays an important role in the phototacatalytic degradation mechanism. Also, it has been determined that Pd or Cu oxides may act as receptors or transmitters of the TiO 2 photogenerated electrons and thus modify the degradation mechanism. Different redox reactions have been proposed according to the obtained results
Revealing the Microstructural evolution in Cu-Cr nanocrystalline alloys during high pressure torsion

Energy Technology Data Exchange (ETDEWEB)

Guo, Jinming; Rosalie, Julian M.; Pippan, Reinhard; Zhang, Zaoli, E-mail: zaoli.zhang@oeaw.ac.at

2017-05-17

Usually immiscible Cu-Cr compounds in equilibrium condition were mechanically processed via high pressure torsion with large and controlled strains. A systematical investigation on 57 wt%Cu − 43 wt%Cr was carried out to get insights into the microstructural evolution of Cu-Cr nanocomposites and their dissolution process, as well as to determine the solid solubility limit of Cu and Cr elements under severe deformation. Microstructural evolution was captured with grain refinement from micron-size down to less than 20 nm as the increase of strains. A strain-saturated state in 57 wt%Cu − 43 wt%Cr bulk was achieved after 100 rotations deformation (effective strain 1360), with a stable grain size of 13.7 nm and invariable hardness of 480–495 HV. Fine scanning of X-ray diffraction and sub-nanometer scale measurements of energy-dispersive X-ray spectroscopy showed that 32 wt% Cu could be fully dissolved into Cr matrix, and conversely solubility of Cr in Cu was determined to be about 3 wt% after an enough amount of deformation. The phase fraction change associated with Cu dissolution into Cr matrix during continuous deformation was captured and accurately calculated, indicating a negative exponential phase change mode. A phenomenological intermixing mechanism based on the kinetic competition between external forcing mixing and thermal-diffusion induced decomposition was proposed, which was well accordant with the phase evolution observed from experimental results.
Fabrication of a Cu(InGaSe2 Thin Film Photovoltaic Absorber by Rapid Thermal Annealing of CuGa/In Precursors Coated with a Se Layer

Directory of Open Access Journals (Sweden)

Chun-Yao Hsu

2013-01-01

Full Text Available Cu(InGaSe2 (CIGS thin film absorbers are prepared using sputtering and selenization processes. The CuGa/In precursors are selenized during rapid thermal annealing (RTA, by the deposition of a Se layer on them. This work investigates the effect of the Cu content in precursors on the structural and electrical properties of the absorber. Using X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurement, it is found that the CIGS thin films produced exhibit facetted grains and a single chalcopyrite phase with a preferred orientation along the (1 1 2 plane. A Cu-poor precursor with a Cu/( ratio of 0.75 demonstrates a higher resistance, due to an increase in the grain boundary scattering and a reduced carrier lifetime. A Cu-rich precursor with a Cu/( ratio of 1.15 exhibits an inappropriate second phase ( in the absorber. However, the precursor with a Cu/( ratio of 0.95 exhibits larger grains and lower resistance, which is suitable for its application to solar cells. The deposition of this precursor on Mo-coated soda lime glass substrate and further RTA causes the formation of a MoSe2 layer at the interface of the Mo and CIGS.

Synthesis, Characterization and Catalytic Activity of Cu/Cu2O Nanoparticles Prepared in Aqueous Medium

Directory of Open Access Journals (Sweden)

Sayed M. Badawy

2015-07-01

Full Text Available Copper/Copper oxide (Cu/Cu2O nanoparticles were synthesized by modified chemical reduction method in an aqueous medium using hydrazine as reducing agent and copper sulfate pentahydrate as precursor. The Cu/Cu2O nanoparticles were characterized by X-ray Diffraction (XRD, Energy Dispersive X-ray Fluorescence (EDXRF, Scanning Electron Microscope (SEM, and Transmission Electron Microscope (TEM. The analysis revealed the pattern of face-centered cubic (fcc crystal structure of copper Cu metal and cubic cuprites structure for Cu2O. The SEM result showed monodispersed and agglomerated particles with two micron sizes of about 180 nm and 800 nm, respectively. The TEM result showed few single crystal particles of face-centered cubic structures with average particle size about 11-14 nm. The catalytic activity of Cu/Cu2O nanoparticles for the decomposition of hydrogen peroxide was investigated and compared with manganese oxide MnO2. The results showed that the second-order equation provides the best correlation for the catalytic decomposition of H2O2 on Cu/Cu2O. The catalytic activity of hydrogen peroxide by Cu/Cu2O is less than the catalytic activity of MnO2 due to the presence of copper metal Cu with cuprous oxide Cu2O. © 2015 BCREC UNDIP. All rights reservedReceived: 6th January 2015; Revised: 14th March 2015; Accepted: 15th March 2015How to Cite: Badawy, S.M., El-Khashab, R.A., Nayl, A.A. (2015. Synthesis, Characterization and Catalytic Activity of Cu/Cu2O Nanoparticles Prepared in Aqueous Medium. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 169-174. (doi:10.9767/bcrec.10.2.7984.169-174 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.7984.169-174
Solution-processed p-type copper(I) thiocyanate (CuSCN) for low-voltage flexible thin-film transistors and integrated inverter circuits

KAUST Repository

Petti, Luisa

2017-03-17

We report on low operating voltage thin-film transistors (TFTs) and integrated inverters based on copper(I) thiocyanate (CuSCN) layers processed from solution at low temperature on free-standing plastic foils. As-fabricated coplanar bottom-gate and staggered top-gate TFTs exhibit hole-transporting characteristics with average mobility values of 0.0016 cm2 V−1 s−1 and 0.013 cm2 V−1 s−1, respectively, current on/off ratio in the range 102–104, and maximum operating voltages between −3.5 and −10 V, depending on the gate dielectric employed. The promising TFT characteristics enable fabrication of unipolar NOT gates on flexible free-standing plastic substrates with voltage gain of 3.4 at voltages as low as −3.5 V. Importantly, discrete CuSCN transistors and integrated logic inverters remain fully functional even when mechanically bent to a tensile radius of 4 mm, demonstrating the potential of the technology for flexible electronics.
Positron spectroscopy analysis of vacancy-solute nanoaggregates in Al-Cu

International Nuclear Information System (INIS)

Ferragut, R.; Ferro, G.; Biasini, M.; Dupasquier, A.; Somoza, A.

2004-01-01

This work addresses the process of ageing in Al-4wt.% Cu at two temperatures (150 C, 180 C) and in conditions of secondary ageing at temperatures up to 60 C, after artificial ageing treatment at 150 C, Positron lifetime and coincidence Doppler broadening measurements are reported. The analysis shows an initial association of positron trapping sites with Cu (about 9 at.% Cu at the annihilation site) that decreases to 7/6% in the initial stages of ageing, but then increases sharply (up to 25 at.% Cu after 300 hours at 180 C). The positron lifetime also displays an initial decrease followed by a final increase. The results confirm the hypothesis that positrons are not trapped in GP[1] zones, but show that trapping occurs in GP[2] zones formed at 150 C. During secondary ageing, the vacancy-Cu association as well as the positron lifetime decrease with the ageing time. This is attributed to the formation of GP[1] zones due to residual supersaturation. (orig.)
Cu Isotopic Composition in Surface Environments and in Biological Systems: A Critical Review.

Science.gov (United States)

Wang, Zhuhong; Chen, Jiubin; Zhang, Ting

2017-05-18

Copper (Cu) is a transition metal and an essential micronutrient for organisms, but also one of the most widespread toxic inorganic contaminants at very high content. The research on Cu isotopes has grown rapidly in the last decade. Hitherto, a large number of studies have been published on the theoretical fractionation mechanisms, experimental data and natural variations of Cu isotopes in variable environments and ecosystems. These studies reported a large variation of δ 65 Cu (-16.49 to +20.04‰) in terrestrial samples and showed that Cu isotopes could be fractionated by various biogeochemical processes to different extent. Several papers have previously reviewed the coupling of Cu and Zn isotope systematics, and we give here a tentative review of the recent publications only on Cu isotopesin variable surface repositories, animals and human beings, with a goal to attract much attention to research on Cu (and other metals) behaviors in the environment and biological systems.
Cu Isotopic Composition in Surface Environments and in Biological Systems: A Critical Review

Directory of Open Access Journals (Sweden)

Zhuhong Wang

2017-05-01

Full Text Available Copper (Cu is a transition metal and an essential micronutrient for organisms, but also one of the most widespread toxic inorganic contaminants at very high content. The research on Cu isotopes has grown rapidly in the last decade. Hitherto, a large number of studies have been published on the theoretical fractionation mechanisms, experimental data and natural variations of Cu isotopes in variable environments and ecosystems. These studies reported a large variation of δ65Cu (−16.49 to +20.04‰ in terrestrial samples and showed that Cu isotopes could be fractionated by various biogeochemical processes to different extent. Several papers have previously reviewed the coupling of Cu and Zn isotope systematics, and we give here a tentative review of the recent publications only on Cu isotopesin variable surface repositories, animals and human beings, with a goal to attract much attention to research on Cu (and other metals behaviors in the environment and biological systems.
Non-noble metal Cu-loaded TiO2 for enhanced photocatalytic H2 production.

Science.gov (United States)

Foo, Wei Jian; Zhang, Chun; Ho, Ghim Wei

2013-01-21

Here we have demonstrated the preparation of high-quality, monodispersed and tunable phases of Cu nanoparticles. Structural and chemical composition studies depict the evolution of Cu-Cu(2)O-CuO nanoparticles at various process stages. The loading of Cu and Cu oxide nanoparticles on TiO(2) catalyst has enhanced the photocatalytic H(2) production. Comparatively, H(2) treatment produces well-dispersed Cu nanoparticles with thin oxide shells that show the highest H(2) production amongst the samples. The relatively higher photocatalytic performance is deemed to result from reduced structural defects, higher surface area and dispersivity as well as favorable charge transfer, which inhibits recombination. The Cu nanoparticles are shown to be a promising alternative to noble metal-loaded TiO(2) catalyst systems due to their low cost and high performance in photocatalytic applications.
Synthesis of Cu2O from CuO thin films: Optical and electrical properties

Directory of Open Access Journals (Sweden)

Dhanya S. Murali

2015-04-01

Full Text Available Hole conducting, optically transparent Cu2O thin films on glass substrates have been synthesized by vacuum annealing (5×10−6 mbar at 700 K for 1 hour of magnetron sputtered (at 300 K CuO thin films. The Cu2O thin films are p-type and show enhanced properties: grain size (54.7 nm, optical transmission 72% (at 600 nm and Hall mobility 51 cm2/Vs. The bulk and surface Valence band spectra of Cu2O and CuO thin films are studied by temperature dependent Hall effect and Ultra violet photo electron Spectroscopy (UPS. CuO thin films show a significant band bending downwards (due to higher hole concentration than Cu2O thin films.
Hardening mechanism of an Ag-Pd-Cu-Au dental casting alloy

International Nuclear Information System (INIS)

Seol, Hyo-Joung; Kim, Gi-Chul; Son, Kuk-Hyeon; Kwon, Yong Hoon; Kim, Hyung-Il

2005-01-01

Age-hardening behaviour and the related microstructural changes were studied to elucidate the hardening mechanism of an Ag-Pd-Cu-Au dental casting alloy by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). By considering hardness test and XRD results together, it was revealed that the hardness increased during the early stage of phase transformation of α into α 1 . In the SEM photographs, two phases of matrix and particle-like structures were observed, and the precipitation of element from the matrix progressed during isothermal aging. By SEM observations and EPMA analysis, it could be supposed that the increase in hardness was caused by the diffusion and aggregation of Cu atoms from the Ag-rich α matrix containing Au and Cu in the early stage of age-hardening process, and that the decrease in hardness was caused by the progress of coarsening of Cu-rich lamellar precipitates in the later stage of the age-hardening process. The changes in the Ag-rich matrix caused both the increase and decrease in hardness, and the CuPd phase containing small amounts of Zn and Sn did not contribute to the hardness changes
The development of hydrazine-processed Cu(In,Ga)(Se,S){sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Bob, Brion; Lei, Bao; Chung, Choong-Heui; Yang, Wenbing; Hsu, Wan-Ching; Duan, Hsin-Sheng; Hou, William Wei-Jen; Li, Sheng-Han; Yang, Yang [Department of Materials Science and Engineering, University of California, Los Angeles, CA (United States)

2012-05-15

The hydrazine-based deposition of Cu(In,Ga)(S,Se){sub 2} (CIGS) thin films has attracted considerable attention in recent years due to its potential for the high-throughput production of photovoltaic devices based on this absorber material. This article provides an introduction as well as presenting a complete picture of the current status of hydrazine-based CIGS solar-cell fabrication, including the three major steps of this deposition process: dissolution of the precursor materials in hydrazine, deposition of a film from the resulting precursor solution, and the completion and characterization of a photovoltaic device following absorber deposition. Recent discoveries are then discussed, regarding the dissolution chemistry of the relevant precursor complexes in hydrazine, which together represent the true foundation of this processing method. Recent studies on CIGS film formation are then summarized, including the control and analysis of the crystalline phase, electronic bandgap, and film morphology. Finally, the latest progress in high-performance device fabrication is highlighted, with a focus on optoelectronic characterization including current-voltage, junction capacitance, and minority carrier lifetime measurements. Finally, a discussion and future outlook is provided. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Direct synthesis of RGO/Cu{sub 2}O composite films on Cu foil for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Dong, Xiangmao; Wang, Kun [Key Laboratory for Ultrafine Materials of the Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Chongjun, E-mail: chongjunzhao@ecust.edu.cn [Key Laboratory for Ultrafine Materials of the Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2500 (Australia); Qian, Xiuzhen [Key Laboratory for Ultrafine Materials of the Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen, Shi [School of Information Engineering, Wuhan University of Technology, Wuhan 430070 (China); Li, Zhen, E-mail: zhenl@uow.edu.au [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2500 (Australia); Liu, Huakun; Dou, Shixue [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2500 (Australia)

2014-02-15

Graphical abstract: RGO/Cu{sub 2}O/Cu composites were synthesized by simple hydrothermal treatment of copper foils with graphene oxide, in which the reduction of graphene oxide and the formation of Cu{sub 2}O nanoparticles simultaneously happened in one-pot reaction. These composites can be directly used as electrodes of supercapacitors with the highest specific capacitance of 98.5 F/g at 1 A g{sup −1}, which is much better than that of CuO or Cu{sub 2}O electrodes. -- Highlights: • The RGO/Cu{sub 2}O/Cu composites were obtained by a friendly method in one step. • Improved capacitance performance is realized by the hydrothermal treatment of graphene oxides with Cu foils. • RGO/Cu{sub 2}O/Cu-200 composites exhibit the largest specific capacitance of 98.5 F g{sup −1} at 1 A g{sup −1}. -- Abstract: Reduced graphene oxide/cuprous oxide (RGO/Cu{sub 2}O) composite films were directly synthesized on the surface of copper foil substrates through a straight redox reaction between GO and Cu foil via a hydrothermal approach. Characterization of the resultant composites with X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscope (FESEM) confirms the formation of Cu{sub 2}O and reduction of GO, in which Cu{sub 2}O nanoparticles were well covered by RGO. The resultant composites (referred to as RGO/Cu{sub 2}O/Cu) were directly used as electrodes for supercapacitors, and their electrochemical performance was assessed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectrometry (EIS) in 1 M KOH aqueous solution. A specific capacitance of 98.5 F g{sup −1} at 1 A g{sup −1} was obtained, which is much higher than that of pure Cu{sub 2}O prepared under the same conditions, due to the presence of RGO.
High resolution microdiffraction studies using synchrotron radiation

Science.gov (United States)

Spolenak, R.; Tamura, N.; Valek, B. C.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Brown, W. L.; Marieb, T.; Batterman, B. W.; Patel, J. R.

2002-04-01

The advent of third generation synchrotron light sources in combination with x-ray focusing devices such as Kirkpatrick-Baez mirrors make Laue diffraction on a submicron length scale possible. Analysis of Laue images enables us to determine the deviatoric part of the 3D strain tensor to an accuracy of 2×10-4 in strain with a spatial resolution comparable to the grain size in our thin films. In this paper the application of x-ray microdiffraction to the temperature dependence of the mechanical behavior of a sputtered blanket Cu film and of electroplated damascene Cu lines will be presented. Microdiffraction reveals very large variations in the strain of a film or line from grain to grain. When the strain is averaged over a macroscopic region the results are in good agreement with direct macroscopic stress measurements. However, the strain variations are so large that in some cases in which the average stress is tensile there are some grains actually under compression. The full implications of these observations are still being considered, but it is clear that the mechanical properties of thin film materials are now accessible with new visibility.
Structure and Mechanical Properties of AlSiCuMg Alloy after Thermo Processing

Directory of Open Access Journals (Sweden)

Piątkowski J.

2015-03-01

Full Text Available In the dissertation it has been shown, that so called „time-thermal treatment” (TTT of the alloy in liquid state, as overheating the metal with around 250°C above the Tliq. and detaining it in this temperature for around 30 minutes, improves the mechanical properties (HB, Rm, R0,2. It was ascertained, that overheating the AlSi17Cu5Mg alloy aids the modification, resulting with microcrystalline structure. Uniform arrangement of the Si primeval crystals in the warp, and α(Al solution type, supersaturated with alloying elements present in the base content (Cu, Mg assures not only increased durability in the ambient temperature, but also at elevated temperature (250°C, what is an advantage, especially due to the use in car industry.
Species dependence of [{sup 64}Cu]Cu-Bis(thiosemicarbazone) radiopharmaceutical binding to serum albumins

Energy Technology Data Exchange (ETDEWEB)

Basken, Nathan E. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States)], E-mail: nbasken@purdue.edu; Mathias, Carla J. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States); Lipka, Alexander E. [Department of Statistics, Purdue University, West Lafayette, IN 47907 (United States); Green, Mark A. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States)], E-mail: magreen@purdue.edu

2008-04-15

Introduction: Interactions of three copper(II) bis(thiosemicarbazone) positron emission tomography radiopharmaceuticals with human serum albumin, and the serum albumins of four additional mammalian species, were evaluated. Methods: {sup 64}Cu-labeled diacetyl bis(N{sup 4}-methylthiosemicarbazonato)copper(II) (Cu-ATSM), pyruvaldehyde bis(N{sup 4}-methylthiosemicarbazonato)copper(II) (Cu-PTSM) and ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) were synthesized and their binding to human, canine, rat, baboon and porcine serum albumins quantified by ultrafiltration. Protein binding was also measured for each tracer in human, porcine, rat and mouse serum. Results: The interaction of these neutral, lipophilic copper chelates with serum albumin is highly compound- and species-dependent. Cu-PTSM and Cu-ATSM exhibit particularly high affinity for human serum albumin (HSA), while the albumin binding of Cu-ETS is relatively insensitive to species. At HSA concentrations of 40 mg/ml, '% free' (non-albumin-bound) levels of radiopharmaceutical were 4.0{+-}0.1%, 5.3{+-}0.2% and 38.6{+-}0.8% for Cu-PTSM, Cu-ATSM and Cu-ETS, respectively. Conclusions: Species-dependent variations in radiopharmaceutical binding to serum albumin may need to be considered when using animal models to predict the distribution and kinetics of these compounds in humans.
Electrolyte influence on the Cu nanoparticles electrodeposition onto boron doped diamond electrode; Influencia do eletrolito na eletrodeposicao de nanoparticulas de Cu sobre eletrodo de diamante dopado com boro

Energy Technology Data Exchange (ETDEWEB)

Matsushima, Jorge Tadao; Santos, Laura Camila Diniz; Couto, Andrea Boldarini; Baldan, Mauricio Ribeiro; Ferreira, Neidenei Gomes [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

2012-07-01

This paper presents the electrolyte influence on deposition and dissolution processes of Cu nanoparticles on boron doped diamond electrodes (DDB). Morphological, structural and electrochemical analysis showed BDD films with good reproducibility, quality and reversible in a specific redox system. Electrodeposition of Cu nanoparticles on DDB electrodes in three different solutions was influenced by pH and ionic strength of the electrolytic medium. Analyzing the process as function of the scan rate, it was verified a better efficiency in 0,5 mol L{sup -1} Na{sub 2}SO{sub 4} solution. Under the influence of the pH and ionic strength, Cu nanoparticles on DDB may be obtained with different morphologies and it was important for defining the desired properties. (author)
Operations and Performance of RHIC as a Cu-Cu Collider

CERN Document Server

Pilat, Fulvia Caterina; Bai, Mei; Barton, Donald; Beebe-Wang, Joanne; Blaskiewicz, Michael; Brennan, Joseph M; Bruno, Donald; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Harvey, Margaret; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Lee, Roger C; Litvinenko, Vladimir N; Luo, Yun; MacKay, William W; Marr, Gregory J; Marusic, Al; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oerter, Brian; Ptitsyn, Vadim; Roser, Thomas; Russo, Thomas; Sandberg, Jon; Satogata, Todd; Schultheiss, Carl; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Zaltsman, Alex; Zeno, Keith; Zhang, S Y; Zhang, Wu

2005-01-01

The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction.
Effect of Cu Salt Molarity on the Nanostructure of CuO Prolate Spheroid

Science.gov (United States)

Sabeeh, Sabah H.; Hussein, Hashim Abed; Judran, Hadia Kadhim

Copper sulfate pentahydrate was used as a source of Cu ion with five different molarities (0.02, 0.05, 0.1, 0.15, 2 and 0.25M). XRD, FE-SEM and TEM techniques all showed that CuO samples have polycrystalline monoclinic structure. CuO prolate spheroid is assembled from nanoparticles as building units. It was demonstrated that the purity, morphology, size range of prolate spheroid and density of nano building units are significantly influenced by Cu precursor’s molarity. The pure phase of CuO prolate spheroid was produced via molarity of 0.2M with crystallite size of 15.1565nm while the particle size of building units ranges from 16nm to 21nm. The stability of CuO nanosuspension or nanofluid was evaluated by zeta potential analysis. The obtained properties of specific structure with large surface area of CuO prolate spheroid make it a promising candidate for wide range of potential applications as in nanofluids for cooling purposes.
Synthesis of Cu Nanoparticles Using Copper Carbonate as Cu Source Toward Versatile Applications.

Science.gov (United States)

Yano, Kazuhisa; Ishizaki, Toshitaka; Sugiyama, Hidehiko

2018-07-01

Cu nanoparticles (NPs) coated with polyvinylpyrrolidone (PVP) were fabricated by polyol method using copper carbonate as a raw material. To increase the reaction temperature, glycol multimers such as diethylene glycol, triethylene glycol, or tetraethylene glycol were examined as a solvent. With increasing degree of multimerization, average diameter of Cu NPs decreased. The synthesis of Cu NPs was further investigated by changing reaction temperature, the amount and molecular weight of PVP in triethylene glycol as a solvent. Average diameter and standard deviation of Cu NPs were found to be highly dependent on those factors. As a result, fine Cu NPs ranging from 28 to 67 nm in average size with narrow size distribution (standard deviation: 16-28%) were obtained. The obtained Cu NPs were applied to a nanofluid, which showed higher thermal conductivity than the theoretical value. The antibacterial activity of Cu NPs was also demonstrated, and found to have strong antibacterial activity.
Elastocaloric effect in CuAlZn and CuAlMn shape memory alloys under compression

OpenAIRE

Qian, Suxin; Geng, Yunlong; Wang, Yi; Pillsbury, Thomas E.; Hada, Yoshiharu; Yamaguchi, Yuki; Fujimoto, Kenjiro; Hwang, Yunho; Radermacher, Reinhard; Cui, Jun; Yuki, Yoji; Toyotake, Koutaro; Takeuchi, Ichiro

2016-01-01

This paper reports the elastocaloric effect of two Cu-based shape memory alloys: Cu68Al16Zn16 (CuAlZn) and Cu73Al15Mn12 (CuAlMn), under compression at ambient temperature. The compression tests were conducted at two different rates to approach isothermal and adiabatic conditions. Upon unloading at a strain rate of 0.1 s−1 (adiabatic condition) from 4% strain, the highest adiabatic temperature changes (ΔTad) of 4.0 K for CuAlZn and 3.9 K for CuAlMn were obtained. The maximum stress and hystere...
W-Cu composites subjected to heavy hot deformation

International Nuclear Information System (INIS)

Yu, Yang; Xu, Xiaoqiang; Zhang, Wencong

2017-01-01

The effect of plastic deformation on the properties and microstructure of W-Cu composites produced by multi-pass hot extrusion with steel cup was investigated. W-Cu composites were sintered at 1 100 C and then the sintered billets were firstly extruded at 900 C with different extrusion ratios. The second hot extrusion was performed at 900 C. The plastic deformation of copper phase plays a dominant part during the whole extrusion process. The microstructural evolution of W phase during the whole processing of heavy hot deformation can be divided into different stages. Experimental results indicate that the W agglomeration will be broken into fine particles effectively when the accumulated plastic deformation amounts to 97.6 % after the second extrusion.
W-Cu composites subjected to heavy hot deformation

Energy Technology Data Exchange (ETDEWEB)

Yu, Yang; Xu, Xiaoqiang; Zhang, Wencong [Harbin Institute of Technology-Weihai (China). School of Materials Science and Engineering

2017-04-15

The effect of plastic deformation on the properties and microstructure of W-Cu composites produced by multi-pass hot extrusion with steel cup was investigated. W-Cu composites were sintered at 1 100 C and then the sintered billets were firstly extruded at 900 C with different extrusion ratios. The second hot extrusion was performed at 900 C. The plastic deformation of copper phase plays a dominant part during the whole extrusion process. The microstructural evolution of W phase during the whole processing of heavy hot deformation can be divided into different stages. Experimental results indicate that the W agglomeration will be broken into fine particles effectively when the accumulated plastic deformation amounts to 97.6 % after the second extrusion.

Some links on this page may take you to non-federal websites. Their policies may differ from this site.