WorldWideScience

Sample records for cu alloy anode

  1. Anodic dissolution and corrosion of alloy Cu30Ni in chloride solutions

    International Nuclear Information System (INIS)

    Zolotarev, E.I.

    1989-01-01

    The anodic and corrosion behavior of alloy Cu30Ni is studied in a solution of 3 N NaCl + 0.01 N HCl by a radiometric method using gamma isotopes of 58 Co (as a marker for Ni) and 64 Cu in combination with electrochemical measurements. It was established that under stationary conditions there was uniform dissolution of the alloy both during free corrosion and anodic polarization. The authors obtained partial anodic dissolution curves for the components of the alloy. It was shown that the dissolution kinetics differed from the mechanisms controlling dissolution of the corresponding pure metals. During corrosion of the alloy in an oxygen atmosphere a back precipitation of copper on the surface of the alloy was not observed. The characteristics observed in the corrosion-electrochemical behavior of the alloy in concentrated chloride solutions can be explained by the presence of Ni on the surface of the dissolving alloy

  2. Porous anodic film formation on an Al-3.5 wt% Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Paez, M.A.; Bustos, O.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Wood, G.C.

    2000-03-01

    Anodic film growth has been undertaken on an electropolished Al-3.5 wt % Cu alloy to determine the influence of copper in solid solution on the anodizing behavior. At the commencement of anodizing of the electropolished alloy, in the presence of interfacial enrichment of copper, Al{sup 3+} and Cu{sup 2+} ions egress and O{sup 2{minus}} ion ingress proceed; film growth occurs at the alloy/film interface though O{sup 2{minus}} ion ingress, with outwardly mobile Al{sup 3+} and Cu{sup 2+} ions ejected at the film/electrolyte interface, and field-assisted dissolution proceeding at the bases of pores. Oxidation of copper, in the presence of the enriched layer, is also associated with O{sub 2} gas generation, leading to development of oxygen-filled voids. As a result of significant pressures in the voids, film rupture proceeds, with electrolyte access to the alloy, dissolution of the enriched interfacial layer and re-anodizing. The consequence of such processes in the development of anodic films of increased porosity and reduced efficiency of film formation compared with anodizing of superpure aluminum under similar conditions.

  3. Impact of ac/dc spark anodizing on the corrosion resistance of Al-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Alsrayheen, Enam, E-mail: ealsrayh@ucalgary.ca [Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary AB, T2N 1N4 (Canada); McLeod, Eric, E-mail: hmolero@ucalgary.ca [Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary AB, T2N 1N4 (Canada); Rateick, Richard, E-mail: richard.rateick@honeywell.com [Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary AB, T2N 1N4 (Canada); Molero, Hebert, E-mail: Eric.McLeod@stmu.ab.ca [Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary AB, T2N 1N4 (Canada); Birss, Viola, E-mail: birss@ucalgary.ca [Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary AB, T2N 1N4 (Canada)

    2011-07-01

    An ac/dc spark anodization method was used to deposit an oxide film (6 {+-} 3 {mu}m in thickness) on the Al-Cu alloy AA2219. The oxide films were formed at 10 mA/cm{sup 2} for 30 min in an alkaline silicate solution, showing three main stages of growth. Scanning electron microscopy and electron microprobe analysis revealed that the oxide films are not uniform and consist of three main layers, an inner Al-rich barrier layer ({approx}1 {mu}m), an intermediate Al-Si mixed oxide layer ({approx}2 {+-} 1 {mu}m), and an outer porous Si-rich layer ({approx}3 {+-} 3 {mu}m). In addition, microscopic analysis showed that the Al{sub 2}Cu intermetallics present in the alloy have not been excessively oxidized during the anodization process and thus are retained beneath the oxide film, as desired. The coating passivity and corrosion resistance, evaluated using linear sweep voltammetry (LSV) in pH 7 borate buffer solution and electrochemical impedance spectroscopy (EIS) in 0.86 M NaCl solution, respectively, were both significantly improved after spark-anodization.

  4. The role of anodic dissolution in the stress corrosion cracking of Al-Li-Cu alloy 2090

    International Nuclear Information System (INIS)

    Buchheit, R.G. Jr.; Wall, F.D.; Stoner, G.E.; Moran, J.P.

    1991-01-01

    The short-transverse (S-T) stress corrosion cracking (SCC) behavior of Al-Li-CU alloy 2090 was studied using a static load SCC test technique. Time to failure was measured as a function of applied potential in several different environments. Rapid SCC failures ( br, T1 applied br, matrix where potentials refer to the breakaway potentials of the subgrain boundary T 1 (Al 2 CuLi) phase and the α-Al matrix phase. E br values were measured using potentiodynamic polarization of bulk materials intended to simulate the individual phases found in the subgrain boundary region. Results strongly suggest an anodic dissolution based SCC mechanism for this alloy where selective dissolution of T 1 on the subgrain boundary is a critical step. The unusual pre-exposure embrittlement phenomenon demonstrated by Al- Li alloys is also shown to be consistent with these simple SCC criteria. 21 refs., 9 figs., 6 tabs

  5. Anodization of Zr-Nb-Cu alloy in mandelic acid - effect of solvent and anionic impurities

    International Nuclear Information System (INIS)

    Lavanya, A.; Raghunath Reddy, G.; Ch Anjaneyulu

    2004-01-01

    Anodization of zirconium-niobium-copper (ZNC) alloy in 0.1 M mandelic acid has been carried out. The effect of solvent (ethylene glycol) and added anionic impurities (sulphates, phosphates and carbonates) showed better kinetic results (formation rate, current efficiency and differential field of formation). (author)

  6. Mechanism of Early Stage Corrosion for Boric-sulfuric Acid Anodized 2A97 Al-Cu-Li Alloy Under Tropical Marine Atmosphere

    Directory of Open Access Journals (Sweden)

    LUO Chen

    2016-09-01

    Full Text Available Optical microscopy(OM, scanning electron microscopy(SEM, EDX and EIS combined with ultramicrotomy were employed to investigate the micro morphology, chemical composition and electrochemical properties of anodized 2A97 Al-Cu-Li alloy before and after atmospheric corrosion. The results show that when electrolytes containing combinations of tartaric-sulfuric or boric-sulfuric acid are used to grow the films at different temperatures, boric acid addition and higher temperature allow for higher current density that speeds up the film growth. The pore geometry and structure is similar for different electrolytes. Dispersive dark rusty spots composed of O, Al, Cl, Cu are present on the boric-sulfuric acid anodized specimen after exposure in tropical marine atmosphere for 1 month. Deposition of white corrosion product is found on the specimen surface as well. Severe pitting occurs and develops deeply into the alloy substrate after elongated outdoor exposure. Corrosion propagation is associated with θ-phase particles.

  7. Electrochemical synthesis of SnCo alloy shells on orderly rod-shaped Cu current collectors as anode materials for lithium-ion batteries with enhanced performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Fangwei; Zhang, Hui, E-mail: meszhanghui@zju.edu.cn; Qi, Yue; Wang, Jiazheng; Du, Ning; Yang, Deren

    2013-09-05

    Highlights: •Nanostructured SnCo/Cu electrodes have been successfully fabricated. •A simple electrodeposition approach was employed. •The Cu arrays offer large surface area and improve electronic/ionic conductivity. •The electrodes show improved performance as anode for Li-ion batteries. •The improved performance was attributed to the nanostructured current collectors. -- Abstract: In this article, we report a two-step electrodeposition method for the synthesis of Cu/SnCo core–shell rod-shaped arrays as anodes of lithium-ion batteries. Firstly, the arrayed Cu nanorods with diameters of 200 nm were fabricated on a Cu foil through an electrodeposition method with alumina oxide membrane (AAO) as the template. Secondly, the SnCo alloy shells were subsequently electrodeposited on the surface of the rod-shaped Cu arrays to form the hybrid nanostructures. These hybrid electrodes delivered the enhanced cyclic performance and high rate capability serving as the anode materials for lithium-ion batteries. The improved electrochemical performance might be attributed to the large surface-to-volume area, sufficient buffering space, and high electronic conductivity associated with these 3-dimensional (3D) nanostructures.

  8. Anodic electrochemical treatment of amorphous alloys

    International Nuclear Information System (INIS)

    Isaev, N.I.; Yakovlev, V.B.; Osipov, Eh.K.; Isaev, A.V.; Trofimova, E.A.; Vasil'ev, V.Yu.

    1983-01-01

    The aim of the investigation is to reveal peculiarities of the process of anodic oxidation and properties of anode oxide films, formed on the surface of amorphous alloys. Amorphous alloys on the base of rectifying metals of Zr-Ni, Zr-Cu-Ni, Zr-Al-Ni, Zr-Cu-Sn, Zr-Al, Zr-Mo systems are studied. Electrolytes which do not dissolve or weakly dissolve oxide film, such as boric acid electrolyte (40-45 g/l H 3 BO 3 and 18 cm 3 /l of the 25% aqueous NH 4 OH solution) and 20% H 2 SO 4 solution, are used for oxidation. Results of investigations, carried out on amorphous alloys, contaning noticeable quantities of non-rectifying components - Cu, Ni, Sn, Fe, Mo etc - have shown that non-rectifying components harden a process of anodic oxidation and decrease the current efficiency. Amorphous alloys, containing only rectifying components are oxidated in anodic way, the regularities of film growth being similar to those obtained for crystalline materials

  9. Influence of the heat treatment condition of alloy AlCu4Mg1 on the microstructure and properties of anodic oxide layers

    Science.gov (United States)

    Morgenstern, R.; Dietrich, D.; Sieber, M.; Lampke, T.

    2017-03-01

    Due to their outstanding specific mechanical properties, high-strength, age-hardenable aluminum alloys offer a high potential for lightweight security-related applications. However, the use of copper-alloyed aluminum is limited because of their susceptibility to selective corrosion and their low wear resistance. These restrictions can be overcome and new applications can be opened up by the generation of protective anodic aluminum oxide layers. In contrast to the anodic oxidation of unalloyed aluminum, oxide layers produced on copper-rich alloys exhibit a significantly more complex pore structure. It is the aim of the investigation to identify the influence of microstructural parameters such as size and distribution of the strengthening precipitations on the coating microstructure. The aluminum alloy EN AW-2024 (AlCu4Mg1) in different heat treatment conditions serves as substrate material. The influence of the strengthening precipitations’ size and distribution on the development of the pore structure is investigated by the use of high-resolution scanning electron microscopy. Integral coating properties are characterized by non-destructive and light-microscopic thickness measurements and instrumented indentation tests.

  10. Behavior of alloying elements during anodizing of Mg-Cu and Mg-W alloys in a fluoride/glycerol electrolyte

    Czech Academy of Sciences Publication Activity Database

    Palagonia, M. S.; Němcová, A.; Kuběna, Ivo; Šmíd, Miroslav; Gao, S.; Liu, H.; Zhong, X. L.; Haigh, S. J.; Santamaria, M.; Di Quarto, F.; Habazaki, H.; Skeldon, P.; Thomson, G.

    2015-01-01

    Roč. 162, č. 9 (2015), C487-C494 ISSN 0013-4651 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : alloying element * anodizing * ion beam analysis * magnesium * TEM Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 3.014, year: 2015 http://jes.ecsdl.org/content/162/9/C487.full

  11. Anodization of cast aluminium alloys produced by different casting methods

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2008-08-01

    Full Text Available In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.

  12. Anodic oxidation of Ta/Fe alloys

    International Nuclear Information System (INIS)

    Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

    2003-01-01

    The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

  13. Incorporation of transition metal ions and oxygen generation during anodizing of aluminium alloys

    International Nuclear Information System (INIS)

    Habazaki, H.; Konno, H.; Shimizu, K.; Nagata, S.; Skeldon, P.; Thompson, G.E.

    2004-01-01

    Enrichment of nickel at the alloy/film interface and incorporation of nickel species into the anodic film have been examined for a sputtering-deposited Al-1.2at.%Ni alloy in order to assist understanding of oxygen generation in barrier anodic alumina films. Anodizing of the alloy proceeds in two stages similarly to other dilute aluminium alloys, for example Al-Cr and Al-Cu alloys, where the Gibbs free energies per equivalent for formation of alloying element oxide exceeds the value for alumina. In the first stage, a nickel-free alumina film is formed, with nickel enriching in an alloy layer, 2 nm thick, immediately beneath the anodic oxide film. In the second stage, nickel atoms are oxidized together with aluminium, with oxygen generation forming gas bubbles within the anodic oxide film. This stage commences after accumulation of about 5.4 x 10 15 nickel atoms cm -2 in the enriched alloy layer. Oxygen generation also occurs when a thin layer of the alloy, containing about 2.0 x 10 19 nickel atoms m -2 , on electropolished aluminium, is completely anodized, contrasting with thin Al-Cr and Al-Cu alloy layers on electropolished aluminium, for which oxygen generation is essentially absent. A mechanism of oxygen generation, based on electron impurity levels of amorphous alumina and local oxide compositions, is discussed in order to explain the observations

  14. 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

  15. Corrosion behavior of amorphous and crystalline Cu50Ti50 and Cu50Zr50 alloys

    International Nuclear Information System (INIS)

    Naka, M.; Hoshimoto, K.; Masumoto, T.

    1978-01-01

    Corrosion rates and anodic polarization curves of amorphous and crystalline Cu 50 Ti 50 and Cu 50 Zr 50 alloys have been examined in various acidic, neutral and alkaline solutions. The amorphous alloys are very stable in acidic and alkaline solutions, but unstable in agressive chloride solutions. The corrosion resistance of these amorphous alloys is higher than that of the crystallized alloys. The high corrosion resistance of amorphous alloys is attributable to the high chemical homogeneity of amorphous alloys without localized crystalline defects such as precipitates, segregates, grain boundaries, etc. Metalloid elements play an important role in the corrosion behavior of amorphous alloys; the addition of phosphorus to amorphous Cu-Ti alloy greatly increases the corrosion resistance, even in 1N HCl. (Auth.)

  16. Electrochemical performance of Sn-Sb-Cu film anodes prepared by layer-by-layer electrodeposition

    International Nuclear Information System (INIS)

    Jiang Qianlei; Xue Ruisheng; Jia Mengqiu

    2012-01-01

    A novel layer-by-layer electrodeposition and heat-treatment approach was attempted to obtain Sn-Sb-Cu film anode for lithium ion batteries. The preparation of Sn-Sb-Cu anodes started with galvanostatic electrochemically depositing antimony and tin sequentially on the substrate of copper foil collector. Sn-Sb and Cu-Sb alloys were formed when heated. The SEM analysis showed that the crystalline grains become bigger and the surface of the Sn-Sb-Cu anode becomes more denser after annealing. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed the antimony, tin and copper were alloyed to form SnSb and Cu 2 Sb after heat treatment. The X-ray photoelectron spectroscopy (XPS) analysis showed the surface of the Sn-Sb-Cu electrode was covered by a thin oxide layer. Electrochemical measurements showed that the annealed Sn-Sb-Cu anode has high reversible capacity and good capacity retention. It exhibited a reversible capacity of about 962 mAh/g in the initial cycle, which still remained 715 mAh/g after 30 cycles.

  17. Effects of Alclad Layer and Anodizing Time on Sulfuric Acid Anodizing and Film Properties of 2E12 Aluminum Alloy

    OpenAIRE

    CHEN Gao-hong; HU Yuan-sen; YU Mei; LIU Jian-hua; LI Guo-ai

    2017-01-01

    Alclad and unclad 2E12 aerospace aluminum alloy were treated by sulfuric acid anodic oxidation. The effects of alclad layer and anodizing time on the anodization behaviour and corrosion resistance of anodic oxide layer on 2E12 aluminum alloy were studied. Surface and cross-section morphology of anodic oxide films were observed by scanning electron microscopy. The electrochemical properties of anodic oxide films were analyzed by potentiodynamic polarization curve and electrochemical impedance ...

  18. Bacterial adherence to anodized titanium alloy

    International Nuclear Information System (INIS)

    Peremarch, C Perez-Jorge; Tanoira, R Perez; Arenas, M A; Matykina, E; Conde, A; De Damborenea, J J; Gomez Barrena, E; Esteban, J

    2010-01-01

    The aim of this study was to evaluate Staphylococcus sp adhesion to modified surfaces of anodized titanium alloy (Ti-6Al-4V). Surface modification involved generation of fluoride-containing titanium oxide nanotube films. Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23- meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulphuric/hydrofluoric acid at 20 V for 5 and 60 min to form a 100 nm-thick porous film of 20 nm pore diameter and 230 nm-thick nanotube films of 100 nm in diameter. The amount of fluorine in the oxide films was of 6% and of 4%, respectively. Collection strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis were studied. The adherence study was performed using a previously published protocol by Kinnari et al. The experiments were performed in triplicates. As a result, lower adherence was detected for collection strains in modified materials than in unmodified controls. Differences between clinical strains were detected for both species (p<0.0001, Kruskal-Wallis test), although global data showed similar results to that of collection strains (p<0.0001, Kruskal-Wallis test). Adherence of bacteria to modified surfaces was decreased for both species. The results also reflect a difference in the adherence between S. aureus and S. epidermidis to the modified material. As a conclusion, not only we were able to confirm the decrease of adherence in the modified surface, but also the need to test multiple clinical strains to obtain more realistic microbiological results due to intraspecies differences.

  19. Effect of Copper and Silicon on Al-5%Zn Alloy as a Candidate Low Voltage Sacrificial Anode

    Science.gov (United States)

    Pratesa, Yudha; Ferdian, Deni; Togina, Inez

    2017-05-01

    One common method used for corrosion protection is a sacrificial anode. Sacrificial anodes that usually employed in the marine environment are an aluminum alloy sacrificial anode, especially Al-Zn-In. However, the electronegativity of these alloys can cause corrosion overprotection and stress cracking (SCC) on a high-strength steel. Therefore, there is a development of the sacrificial anode aluminum low voltage to reduce the risk of overprotection. The addition of alloying elements such as Cu, Si, and Ge will minimize the possibility of overprotection. This study was conducted to analyze the effect of silicon and copper addition in Al-5Zn. The experiment started from casting the sacrificial anode aluminum uses electrical resistance furnace in a graphite crucible in 800°C. The results alloy was analyzed using Optical emission spectroscopy (OES), Differential scanning calorimetry, electrochemical impedance spectroscopy, and metallography. Aluminum alloy with the addition of a copper alloy is the most suitable and efficient to serve as a low-voltage sacrificial anode aluminum. Charge transfer resistivity of copper is smaller than silicon which indicates that the charge transfer between the metal and the electrolyte is easier t to occur. Also, the current potential values in coupling with steel are also in the criteria range of low-voltage aluminum sacrificial anodes.

  20. Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation.

    Science.gov (United States)

    Tian, Xi-Ke; Zhao, Xiao-Yu; Zhang, Li-de; Yang, Chao; Pi, Zhen-Bang; Zhang, Su-Xin

    2008-05-28

    To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one.

  1. Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation

    International Nuclear Information System (INIS)

    Tian Xike; Zhao Xiaoyu; Yang Chao; Pi Zhenbang; Zhang Lide; Zhang Suxin

    2008-01-01

    To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one

  2. 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.

  3. Magnesium-based hydrogen alloy anodes for a nickel metal hydrides secondary battery

    Energy Technology Data Exchange (ETDEWEB)

    Cui, N.; Luan, B.; Zhao, H.J.; Liu, H.K.; Dou, S.X. [Univ of Wollongong, Wollongong, NSW (Australia). Centre for Superconducting and Electronic Materials

    1996-12-31

    Extensive work has been carried out in our group to try utilizing magnesium-based hydrogen storage alloys as a low cost and high performance anode materials for Ni-MH battery. It was found that the modified Mg{sub 2}Ni alloy anodes were able to be charged-discharged effectively in a KOH aqueous solution at ambient temperature. The discharge capacity and cycle have been substantially improved in four ways: (1) by partial substitution of La, Ti, V, Zr, Ca for Mg and Fe, Co, Cu, Al, Si, Y, Mn for Ni in Mg{sub 2}Ni; (2) by composite of Mg{sub 2}Ni with another hydrogen storage alloys; (3) by room-temperature surface microencapsulation and, (4) by ultrasound treatment of alloy powders. A discharge capacity of 170 mAh/g has been obtained from the modified Mg{sub 2}Ni-type alloy electrode, and the cycle life has exceeded 350 cycles. The high rate dischargeability was also significantly improved by the modification. It was concluded that magnesium-based hydrogen storage alloys would become promising anode materials for Ni- MH secondary battery with further improvement of discharge capacity and cycling performance

  4. Magnesium-based hydrogen alloy anodes for a nickel metal hydrides secondary battery

    International Nuclear Information System (INIS)

    Cui, N.; Luan, B.; Zhao, H.J.; Liu, H.K.; Dou, S.X.

    1996-01-01

    Extensive work has been carried out in our group to try utilizing magnesium-based hydrogen storage alloys as a low cost and high performance anode materials for Ni-MH battery. It was found that the modified Mg 2 Ni alloy anodes were able to be charged-discharged effectively in a KOH aqueous solution at ambient temperature. The discharge capacity and cycle have been substantially improved in four ways: (1) by partial substitution of La, Ti, V, Zr, Ca for Mg and Fe, Co, Cu, Al, Si, Y, Mn for Ni in Mg 2 Ni; (2) by composite of Mg 2 Ni with another hydrogen storage alloys; (3) by room-temperature surface microencapsulation and, (4) by ultrasound treatment of alloy powders. A discharge capacity of 170 mAh/g has been obtained from the modified Mg 2 Ni-type alloy electrode, and the cycle life has exceeded 350 cycles. The high rate dischargeability was also significantly improved by the modification. It was concluded that magnesium-based hydrogen storage alloys would become promising anode materials for Ni- MH secondary battery with further improvement of discharge capacity and cycling performance

  5. Grindability of cast Ti-Cu alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takada, Yukyo; Kiyosue, Seigo; Yoda, Masanobu; Woldu, Margaret; Cai, Zhuo; Okuno, Osamu; Okabe, Toru

    2003-07-01

    The purpose of the present study was to evaluate the grindability of a series of cast Ti-Cu alloys in order to develop a titanium alloy with better grindability than commercially pure titanium (CP Ti), which is considered to be one of the most difficult metals to machine. Experimental Ti-Cu alloys (0.5, 1.0, 2.0, 5.0, and 10.0 mass% Cu) were made in an argon-arc melting furnace. Each alloy was cast into a magnesia mold using a centrifugal casting machine. Cast alloy slabs (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layer (250 microm) was removed, were ground using a SiC abrasive wheel on an electric handpiece at four circumferential speeds (500, 750, 1000, or 1250 m/min) at 0.98 N (100 gf). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1min. Data were compared to those for CP Ti and Ti-6Al-4V. For all speeds, Ti-10% Cu alloy exhibited the highest grindability. For the Ti-Cu alloys with a Cu content of 2% or less, the highest grindability corresponded to an intermediate speed. It was observed that the grindability increased with an increase in the Cu concentration compared to CP Ti, particularly for the 5 or 10% Cu alloys at a circumferential speed of 1000 m/min or above. By alloying with copper, the cast titanium exhibited better grindability at high speed. The continuous precipitation of Ti(2)Cu among the alpha-matrix grains made this material less ductile and facilitated more effective grinding because small broken segments more readily formed.

  6. The characteristics of anodic coating of Al-alloy claddings

    International Nuclear Information System (INIS)

    Yang Yong; Zou Benhui; Guo Hong; Du Yanhua; Bai Zhiyong; Cai Zhenfang

    2014-01-01

    Aluminum alloy claddings of research reactor fuel elements should be corroded by sodium hydroxide solution and anodized in sulfuric acid solution, but there are often some uneven color phenomena on surfaces, and sometimes regions of 'black and white stripes' appear. In order to study the relationship of colorful stripes on coatings and the surface morphology of aluminum alloy claddings corroded by sodium hydroxide solution, surface microstructures and second phase particles of the aluminum alloy claddings, which were corroded by sodium hydroxide solution, are investigated metallographically and via SEM analysis; Meanwhile, thickness, microstructure, chemical composition and construction of anodic oxidation coatings on aluminum coatings are analyzed. It is shown that: 1) the darker the surface color of corroded aluminum alloy claddings is, the darker of anodic oxidation coating; 2) there are many micro-pores on anodized oxidation coatings, which is much similar to that of corroded aluminum alloy claddings according to the morphology and distribution. So, it can be deduced that the surface morphology of anodic coatings is inherited from the corroded surfaces. (authors)

  7. Aluminum alloy and associated anode and battery

    International Nuclear Information System (INIS)

    Tarcy, G.P.

    1990-01-01

    This patent describes an aluminum alloy. It comprises: eutectic amounts of at least two alloying elements selected from the group consisting of bismuth, cadmium, scandium, gallium, indium, lead, mercury, thallium, tin, and zinc with the balance being aluminum and the alloying elements being about 0.01 to 3.0 percent by weight of the alloy

  8. 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.

  9. 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.

  10. Effects of Alclad Layer and Anodizing Time on Sulfuric Acid Anodizing and Film Properties of 2E12 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    CHEN Gao-hong

    2017-07-01

    Full Text Available Alclad and unclad 2E12 aerospace aluminum alloy were treated by sulfuric acid anodic oxidation. The effects of alclad layer and anodizing time on the anodization behaviour and corrosion resistance of anodic oxide layer on 2E12 aluminum alloy were studied. Surface and cross-section morphology of anodic oxide films were observed by scanning electron microscopy. The electrochemical properties of anodic oxide films were analyzed by potentiodynamic polarization curve and electrochemical impedance spectroscopy. The results show that the protective anodic oxide layers are formed on alclad and unclad 2E12 aluminum alloy. The film thickness increases with anodizing time extending. The copper rich second phase particles lead to more cavity defects and even micro cracks on anodic oxide films of unclad 2E12 aluminum alloy. The anodic oxide films on alclad 2E12 aluminum alloy are thicker and have fewer cavity defects, resulting in better corrosion resistance. The films obtained after 30min and 45min anodic oxidation treatment exhibit lower corrosion current and higher impedance of the porous layer than other anodizing time.

  11. The electrochemical properties of melt-spun Al-Si-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Linping; Wang Fei; Liang Pu; Song Xianlei; Hu Qing [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Sun Zhanbo, E-mail: szb@mail.xjtu.edu.cn [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Song Xiaoping; Yang Sen; Wang Liqun [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2011-10-03

    Highlights: {yields} Non-equilibrium Al{sub 75-X}Si{sub 25}Cu{sub X} alloys exhibit high lithiation storages. {yields} The lithiation mechanism is different from melt-spun Al-Si-Mn system. {yields} The structural evolution is mitigated in the non-equilibrium alloys. {yields} Volume variation is alleviated due to the co-existence of Al{sub 2}Cu, {alpha}-Si and {alpha}-Al. - Abstract: Melt spinning was used to prepare Al{sub 75-X}Si{sub 25}Cu{sub X} (X = 1, 4, 7, 10 mol%) alloy anode materials for lithium-ion batteries. A metastable supersaturated solid solution of Si and Cu in fcc-Al, {alpha}-Si and Al{sub 2}Cu co-existed in the alloys. Nano-scaled {alpha}-Al grains, as the matrix, formed in the as-quenched ribbons. The Al{sub 74}Si{sub 25}Cu{sub 1} and Al{sub 71}Si{sub 25}Cu{sub 4} anodes exhibited initial discharge specific capacities of 1539 mAh g{sup -1}, 1324 mAh g{sup -1} and reversible capacities above 472 mAh g{sup -1}, 508 mAh g{sup -1} at the 20th cycle, respectively. The specific capacities reduced as the increase of the Cu content. AlLi intermetallic compound was detected in the lithiated alloys. It is concluded that the lithiation mechanism of the Al-Si-based alloys can be affected by the third component. The structural evolution and volume variation can be mitigated due to the formation of non-equilibrium state and the co-existence of nano-scaled {alpha}-Al, {alpha}-Si, and Al{sub 2}Cu for the present alloys.

  12. The electrochemical properties of melt-spun Al-Si-Cu alloys

    International Nuclear Information System (INIS)

    Zhang Linping; Wang Fei; Liang Pu; Song Xianlei; Hu Qing; Sun Zhanbo; Song Xiaoping; Yang Sen; Wang Liqun

    2011-01-01

    Highlights: → Non-equilibrium Al 75-X Si 25 Cu X alloys exhibit high lithiation storages. → The lithiation mechanism is different from melt-spun Al-Si-Mn system. → The structural evolution is mitigated in the non-equilibrium alloys. → Volume variation is alleviated due to the co-existence of Al 2 Cu, α-Si and α-Al. - Abstract: Melt spinning was used to prepare Al 75-X Si 25 Cu X (X = 1, 4, 7, 10 mol%) alloy anode materials for lithium-ion batteries. A metastable supersaturated solid solution of Si and Cu in fcc-Al, α-Si and Al 2 Cu co-existed in the alloys. Nano-scaled α-Al grains, as the matrix, formed in the as-quenched ribbons. The Al 74 Si 25 Cu 1 and Al 71 Si 25 Cu 4 anodes exhibited initial discharge specific capacities of 1539 mAh g -1 , 1324 mAh g -1 and reversible capacities above 472 mAh g -1 , 508 mAh g -1 at the 20th cycle, respectively. The specific capacities reduced as the increase of the Cu content. AlLi intermetallic compound was detected in the lithiated alloys. It is concluded that the lithiation mechanism of the Al-Si-based alloys can be affected by the third component. The structural evolution and volume variation can be mitigated due to the formation of non-equilibrium state and the co-existence of nano-scaled α-Al, α-Si, and Al 2 Cu for the present alloys.

  13. Solid solution lithium alloy cermet anodes

    Science.gov (United States)

    Richardson, Thomas J.

    2013-07-09

    A metal-ceramic composite ("cermet") has been produced by a chemical reaction between a lithium compound and another metal. The cermet has advantageous physical properties, high surface area relative to lithium metal or its alloys, and is easily formed into a desired shape. An example is the formation of a lithium-magnesium nitride cermet by reaction of lithium nitride with magnesium. The reaction results in magnesium nitride grains coated with a layer of lithium. The nitride is inert when used in a battery. It supports the metal in a high surface area form, while stabilizing the electrode with respect to dendrite formation. By using an excess of magnesium metal in the reaction process, a cermet of magnesium nitride is produced, coated with a lithium-magnesium alloy of any desired composition. This alloy inhibits dendrite formation by causing lithium deposited on its surface to diffuse under a chemical potential into the bulk of the alloy.

  14. Anodic behavior of alloy 22 in bicarbonate containing media: Effect of alloying

    International Nuclear Information System (INIS)

    Zadorozne, N S; Giordano, C M; Rebak, R B; Ares, A E; Carranza, R M

    2012-01-01

    Alloy 22 is one of the candidates for the manufacture of high level nuclear waste containers. These containers provide services in natural environments characterized by multi-ionic solutions.It is estimated they could suffer three types of deterioration: general corrosion, localized corrosion (specifically crevice corrosion) and stress corrosion cracking (SCC). It has been confirmed that the presence of bicarbonate and chloride ions is necessary to produce cracking, . It has also been determined that the susceptibility to SCC could be related to the occurrence of an anodic peak in the polarization curves in these media at potentials below transpassivity. The aim of this work is to study the effect of alloying elements on the anodic behavior of Alloy 22 in media containing bicarbonate and chloride ions at different concentrations and temperatures. Polarization curves were made on alloy 22 (Ni-22% Cr-13% Mo), Ni-Mo (Ni-28, 5% Mo) and Ni-Cr (Ni-20% Cr) in the following solutions: 1 mol/L NaCl at 90 o C, and 1.148 mol/L NaHCO 3 ; 1.148 mol/L NaHCO 3 + 1 mol/L NaCl; 1.148 mol/L NaHCO 3 + 0.1 mol/L NaCl, at 90 o C, 75 o C, 60 o C and 25 o C. It was found that alloy 22 has a anodic current density peak at potentials below transpassivity, only in the presence of bicarbonate ions. Curves performed in 1 mol/L NaCl did not show any anodic peak, in any of the tested alloys. The curves made on alloys Ni-Mo and Ni-Cr in the presence of bicarbonate ions, allowed to determine that Cr, is responsible for the appearance of the anodic peak in alloy 22. The curves of alloy Ni-Mo showed no anodic peak in the studied conditions. The potential at which the anodic peak appears in alloy 22 and Ni-Cr alloy, increases with decreasing temperature. The anodic peak was also affected by solution composition. When chloride ion is added to bicarbonate solutions, the anodic peak is shifted to higher potential and current densities, depending on the concentration of added chloride ions (author)

  15. Effects of sodium tartrate anodizing on fatigue life of TA15 titanium alloy

    Directory of Open Access Journals (Sweden)

    Fu Chunjuan

    2015-08-01

    Full Text Available Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy. The sodium tartrate anodizing is a new kind of environmental anodizing method. In this work, the effects of sodium tartrate anodizing on mechanical property were studied. The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former. The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared. The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life. While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.

  16. Recycled tetrahedron-like CuCl from waste Cu scraps for lithium ion battery anode.

    Science.gov (United States)

    Hou, Hongying; Yao, Yuan; Liu, Song; Duan, Jixiang; Liao, Qishu; Yu, Chengyi; Li, Dongdong; Dai, Zhipeng

    2017-07-01

    The wide applications of metal Cu inevitably resulted in a large quantity of waste Cu materials. In order to recover the useful Cu under the mild conditions and reduce the environmental emission, waste Cu scraps were recycled in the form of CuCl powders with high economic value added (EVA) via the facile hydrothermal route. The recycled CuCl powders were characterized in terms of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results suggested that the recycled CuCl powders consisted of many regular tetrahedron-like micro-particles. Furthermore, in order to reduce the cost of lithium ion battery (LIB) anode and build the connection of waste Cu scraps and LIB, the recycled CuCl powders were evaluated as the anode active material of LIB. As expected, the reversible discharge capacity was about 171.8mAh/g at 2.0C even after 50 cycles, implying the satisfactory cycle stability. Clearly, the satisfactory results may open a new avenue to develop the circular economy and the sustainable energy industry, which would be very important in terms of both the resource recovery and the environmental protection. Copyright © 2017. Published by Elsevier Ltd.

  17. 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.

  18. A Study on Sealing Process of Anodized Al Alloy Film

    Science.gov (United States)

    Tsujita, Takeshi; Sato, Hiroshi; Tsukahara, Sonoko; Ishikawa, Yuuichi

    Since sealing is an important process to improve the corrosion resistance in practical application of anodized aluminum, we prepared anodic oxide films on A5052 alloy in an oxalic acid bath and a sulfuric acid bath, sealed them at various conditions, and analyzed them by scanning electron microscopy, acid-dissolution examination, admittance measurements and infrared spectroscopy. The pore radius of the oxalic acid anodized film was about 5 times larger than that of sulfuric acid anodized film, while the corrosion resistance of the former showed about 2 times higher value than the latter with the same sealed state and amount of hydroxide formed by sealing process of the former was 6 times larger than the latter, respectively. Steam sealing formed dense hydroxide and boiling water sealing formed big coral-like hydroxide, whereas the corrosion resistance of the film sealed by the former showed about 1.5 times higher value than that sealed by the latter, respectively. Thus microstructure of anodic oxide films and their surface morphology after sealing process clearly depended on their anodizing solution and the sealing condition and showed obvious relation to electric and corrosive properties.

  19. Anodic behavior of nickel alloys in media containing bicarbonate ions

    International Nuclear Information System (INIS)

    Zadorozne, N.S; Carranza, R. M.; Giordano, C.M.

    2011-01-01

    Alloy 22 has been designed to resist corrosion in oxidizing and reducing conditions. Thanks to these properties it is considered a possible candidate for the fabrication of containers of high-level radioactive waste. Since the containers provide services in natural environments characterized by multi-ionic solutions, it is estimated they could suffer three types of deterioration: general corrosion, localized corrosion (specifically crevice corrosion) and stress corrosion cracking (SCC). It has been confirmed that the presence of bicarbonate and chloride ions is required in order to produce cracking. It has also been determined that the susceptibility to SCC could be related to the occurrence of an anodic peak in the polarization curves in these media potentials below trans-passivity. The aim of this work is to study the anodic behavior of Alloy 22 in different media containing bicarbonate and chloride ions in various concentrations and temperatures and compare the results with other alloys containing nickel, and relate them to the susceptibility to stress corrosion cracking in a future job. Polarization curves were made on alloy 22 (Ni-Cr-Mo), 600 (Ni- Cr-Fe), 800h (Ni-Fe- Cr) and 201 (Ni commercially pure) in the following environments: 1.148 mol/L NaHCO 3 , 1.148 mol/L NaHCO 3 + 1 mol/L NaCl, 1.148 mol/L NaHCO 3 + 0.1 mol/L NaCl. The tests were performed at the following temperatures: 90°C, 75°C, 60°C and 25°C. It was found that alloy 22 has a current peak in the anodic domain at potentials below trans-passivity between 200 and 300 m VECS, when the test temperature was 90°C. The potential, at which this peak occurred, increased with decreasing temperature. Also there was a variation of the peak with the composition of the solution. When bicarbonate ions were added to a solution containing chloride ions, the peak potential shifted to higher current densities, depending on the concentration of added chloride ions. It was found that diminishing the content of

  20. CuLi2Sn and Cu2LiSn: Characterization by single crystal XRD and structural discussion towards new anode materials for Li-ion batteries.

    Science.gov (United States)

    Fürtauer, Siegfried; Effenberger, Herta S; Flandorfer, Hans

    2014-12-01

    The stannides CuLi 2 Sn (CSD-427095) and Cu 2 LiSn (CSD-427096) were synthesized by induction melting of the pure elements and annealing at 400 °C. The phases were reinvestigated by X-ray powder and single-crystal X-ray diffractometry. Within both crystal structures the ordered CuSn and Cu 2 Sn lattices form channels which host Cu and Li atoms at partly mixed occupied positions exhibiting extensive vacancies. For CuLi 2 Sn, the space group F-43m. was verified (structure type CuHg 2 Ti; a =6.295(2) Å; wR 2 ( F ²)=0.0355 for 78 unique reflections). The 4( c ) and 4( d ) positions are occupied by Cu atoms and Cu+Li atoms, respectively. For Cu 2 LiSn, the space group P 6 3 / mmc was confirmed (structure type InPt 2 Gd; a =4.3022(15) Å, c =7.618(3) Å; wR 2 ( F ²)=0.060 for 199 unique reflections). The Cu and Li atoms exhibit extensive disorder; they are distributed over the partly occupied positions 2( a ), 2( b ) and 4( e ). Both phases seem to be interesting in terms of application of Cu-Sn alloys as anode materials for Li-ion batteries.

  1. Fabrication of a micrometer Ni–Cu alloy column coupled with a Cu micro-column for thermal measurement

    International Nuclear Information System (INIS)

    Lin, J C; Chang, T K; Yang, J H; Jeng, J H; Lee, D L; Jiang, S B

    2009-01-01

    Micrometer Ni–Cu alloy columns have been fabricated by the micro-anode-guided electroplating (MAGE) process in the citrate bath. The surface morphology and chemical composition of the micro-columns were determined by copper concentration in the bath and by the electrical bias of MAGE. When fabricated in a bath of dilute copper (i.e. 4 mM) at lower voltages (e.g. 3.8 and 4.0 V), the alloy micro-columns revealed uniform diameter and smooth appearance. The alloy composition demonstrated an increase in the wt% ratio of Ni/Cu from 75/25, 80/20, 83/17 to 87/13 with increasing electrical bias from 3.8, 4.0, 4.2 to 4.4 V. However, it decreases from 75/25, 57/43 to 47/53 with increasing copper concentration from 4, 8 to 12 mM in the bath. Citrate plays a role in forming complexes with nickel and copper at similar reduction potentials, thus reducing simultaneously to Ni–Cu alloy. The mechanism for fabricating alloy micro-columns could be delineated on the basis of cathodic polarization of the complexes. A couple of micro-columns were fabricated using MAGE in constructing a pure copper micro-column on the top of a Ni/Cu (at 47/53) alloy micro-column. This micro-thermocouple provides a satisfactory measurement with good sensitivity and precision

  2. Structure of the Copper–Enriched Layer Introduced by Anodic Oxidation of Copper-Containing Aluminium Alloy

    International Nuclear Information System (INIS)

    Hashimoto, T.; Zhou, X.; Skeldon, P.; Thompson, G.E.

    2015-01-01

    This paper investigates the structure of the copper–enriched layer formed at the alloy/anodic film interface during anodizing of Al–2 wt.% Cu binary alloy using transmission electron microscopy. It was revealed that θ′ phase was formed within the copper–enriched layer. For the copper–enriched layer formed on {1 0 0} aluminum planes, the interface between the aluminum matrix and the θ′ phase within the copper-enriched layer is coherent. For the copper–enriched layer formed on {1 1 0} and {1 1 1} aluminum planes, the interfaces between the aluminum matrix and the θ′ phase within the copper-enriched layer are semi-coherent or incoherent. The interfacial coherency influences the formation of oxygen gas bubbles within the resultant anodic films.

  3. 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

  4. Water and oil wettability of anodized 6016 aluminum alloy surface

    Science.gov (United States)

    Rodrigues, S. P.; Alves, C. F. Almeida; Cavaleiro, A.; Carvalho, S.

    2017-11-01

    This paper reports on the control of wettability behaviour of a 6000 series aluminum (Al) alloy surface (Al6016-T4), which is widely used in the automotive and aerospace industries. In order to induce the surface micro-nanostructuring of the surface, a combination of prior mechanical polishing steps followed by anodization process with different conditions was used. The surface polishing with sandpaper grit size 1000 promoted aligned grooves on the surface leading to static water contact angle (WCA) of 91° and oil (α-bromonaphthalene) contact angle (OCA) of 32°, indicating a slightly hydrophobic and oleophilic character. H2SO4 and H3PO4 acid electrolytes were used to grow aluminum oxide layers (Al2O3) by anodization, working at 15 V/18° C and 100 V/0 °C, respectively, in one or two-steps configuration. Overall, the anodization results showed that the structured Al surfaces were hydrophilic and oleophilic-like with both WCA and OCA below 90°. The one-step configuration led to a dimple-shaped Al alloy surface with small diameter of around 31 nm, in case of H2SO4, and with larger diameters of around 223 nm in case of H3PO4. The larger dimples achieved with H3PO4 electrolyte allowed to reach a slight hydrophobic surface. The thicker porous Al oxide layers, produced by anodization in two-step configuration, revealed that the liquids can penetrate easily inside the non-ordered porous structures and, thus, the surface wettability tended to superhydrophilic and superoleophilic character (CA OCA. This inversion in favour of the hydrophilic-oleophobic surface behaviour is of great interest either for lubrication of mechanical components or in water-oil separation process.

  5. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  6. Effect of microstructure on corrosion behavior of Ag-30Cu-27Sn alloy in vitro media

    International Nuclear Information System (INIS)

    Salehisaki, Mehdi; Aryana, Maryam

    2014-01-01

    Highlights: • High cooling rates decrease the number of Ag intermetallic particles in Cu-rich phase. • Increasing cooling rate improves corrosion behavior of Ag-30Cu-27Sn dental alloy. • Cathode/anode ratio in Cu-rich phases determines the corrosion behavior of alloy. - Abstract: In the present work, three simple heat treatment cycles were used to study the effects of microstructure on electrochemical corrosion behavior of Ag-30Cu-27Sn dental alloy. The electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization tests were carried out to investigate the corrosion behavior of as-cast and heat treated samples in synthetic saliva solution. The presence of intermetallic compounds were studied by X-ray diffraction method (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray detector (EDAX). The microstructural observations and electrochemical corrosion results revealed that, increasing the cooling rate improves the corrosion behavior of under investigation samples. Improvement of the corrosion behavior is attributed to reducing the area of fine distributed Ag 3 Sn islands in the Cu-rich matrix which decrease the cathode/anode ratio of microgalvanic cells

  7. 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.

  8. Effect of samarium in corrosion and microstructure of Al-5Zn-0.5Cu as low driving voltage sacrificial anode

    Science.gov (United States)

    Pratesa, Yudha; Ferdian, Deni; Ramadhan, Fajar Yusya; Maulana, Bramuda

    2018-05-01

    Sacrificial Anode Low voltage is the latest generation of the sacrificial anode that can prevent the occurrence of Hydrogen Cracking (HIC) due to overprotection. The Al-5n-0.5Cu alloy showed the potential to be developed as the new sacrificial anode. However, the main problem is copper made Al2Cu intermetallic in grain boundary. Samarium is added to modify the shape of the intermetallic to make it finer and make the corrosion uniform. Several characterizations were conducted to analyze the effect of Samarium. Scanning electron microscope (SEM) and Energy dispersive spectroscopy was used to analyzed the microstructure of the alloy. Metallography preparation was prepared for SEM analysis. Corrosion behavior was characterized by cyclic polarization in 3.5% NaCl solution. The results show samarium can change the shape of intermetallic and refine the grains. In addition, samarium makes better pitting resistance and exhibits a tendency for uniform corrosion. It is indicated by the loop reduction (ΔEpit-prot). Current density increased as an effect of samarium addition from 6x10-5 Ampere (Al-5Zn-0.5Cu) to 2.5x10-4 Ampere (Al-5Zn-0.5Cu-0.5Sm). Steel potential protection increased after addition of samarium which is an indication the possibility of Al-Zn-Cu-Sm to be used as low voltage sacrificial anode.

  9. Effect of Nitric and Oxalic Acid Addition on Hard Anodizing of AlCu4Mg1 in Sulphuric Acid

    Directory of Open Access Journals (Sweden)

    Maximilian Sieber

    2018-02-01

    Full Text Available The anodic oxidation process is an established means for the improvement of the wear and corrosion resistance of high-strength aluminum alloys. For high-strength aluminum-copper alloys of the 2000 series, both the current efficiency of the anodic oxidation process and the hardness of the oxide coatings are significantly reduced in comparison to unalloyed substrates. With regard to this challenge, recent investigations have indicated a beneficial effect of nitric acid addition to the commonly used sulphuric acid electrolytes both in terms of coating properties and process efficiency. The present work investigates the anodic oxidation of the AlCu4Mg1 alloy in a sulphuric acid electrolyte with additions of nitric acid as well as oxalic acid as a reference in a full-factorial design of experiments (DOE. The effect of the electrolyte composition on process efficiency, coating thickness and hardness is established by using response functions. A mechanism for the participation of the nitric acid additive during the oxide formation is proposed. The statistical significance of the results is assessed by an analysis of variance (ANOVA. Eventually, scratch testing is applied in order to evaluate the failure mechanisms and the abrasion resistance of the obtained conversion coatings.

  10. 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.

  11. Measurement of thermoelectric power of Fe-Cu binary alloys

    International Nuclear Information System (INIS)

    Joubouji, Katsuo

    2007-01-01

    In INSS, non-destructive evaluation (NDE) of irradiation embrittlement of low alloy steel using thermoelectric power (TEP) measurement has been considered, as well as NDE of thermal aging of cast duplex stainless steel which has been studied in recent years. Material degradation is evaluated based on a relation between progress of the degradation and change in TEP due to change in material structure caused by the degradation event. So it is necessary for NDE of irradiation embrittlement to measure the change in TEP due to precipitation of Cu contained as an impurity, which is known as one of the reasons for the embrittlement. In this study, TEP of Fe-Cu binary alloys with different Cu content was measured for investigation of the relationship between TEP of the alloys and Cu content. In addition, appropriateness of measuring TEP of Fe-Cu binary alloy in the same way to measure TEP of duplex stainless steel was examined. It was found that increment of Cu contained in the alloys changed TEP in a negative direction and the rate was evaluated as -6.6μV/K/wt%Cu. There were the cases that it took 20 minutes for measurement values to become stable in measurement of Fe-Cu binary alloys. It was much longer than the time taken in measurement of duplex stainless steel. So the measurement time per a point was extended to 60 minutes in case of Fe-Cu binary alloys. (author)

  12. Electrochemical machining of titanium alloys with the use of anodal activating pulses

    International Nuclear Information System (INIS)

    Davydov, A.D.; Klepikov, R.P.; Moroz, I.I.

    1980-01-01

    A comparative investigation of electrochemical machining of VT-6 titanium alloy by direct current and in different pulse mode is carried out taking into account the peculiarities of anodal behaviour of titanium alloys at high current desities. The mode of electrochemical machining of VT-6 alloy with activating pulses is chosen. It allows to conduct a process at lower voltages and small interelectrode gaps

  13. Cermet anode compositions with high content alloy phase

    Science.gov (United States)

    Marschman, Steven C.; Davis, Norman C.

    1989-01-01

    Cermet electrode compositions comprising NiO-NiFe.sub.2 O.sub.4 -Cu-Ni, and methods for making, are disclosed. Addition of nickel metal prior to formation and densification of a base mixture into the cermet allows for an increase in the total amount of copper and nickel that can be contained in the NiO-NiFe.sub.2 O.sub.4 oxide system. Nickel is present in a base mixture weight concentration of from 0.1% to 10%. Copper is present in the alloy phase in a weight concentration of from 10% to 30% of the densified composition. Such cermet electrodes can be formed to have electrical conductivities well in excess of 100 ohm.sup.-1 cm.sup.-1. Other alloy and oxide system cermets having high content metal phases are also expected to be manufacturable in accordance with the invention.

  14. Microscopic observation of pattern attack by aggressive ions on finished surface of aluminium alloy sacrificial anode

    International Nuclear Information System (INIS)

    Zaifol Samsu; Muhammad Daud; Siti Radiah Mohd Kamarudin; Nur Ubaidah Saidin; Azali Muhammad; Mohd Shaari Ripin; Rusni Rejab; Mohd Shariff Sattar

    2010-01-01

    This paper presents the results of a microscopic observation on submerged finished surface of aluminium alloy sacrificial anode. Experimental tests were carried out on polished surface aluminium anode exposed to seawater containing aggressive ions in order to observe of pattern corrosion attack on corroding surface of anode. Results have shown, at least under the present testing condition, that surface of sacrificial anode were attack by an aggressive ion such as chloride along grain boundaries. In addition, results of microanalysis showed that the corrosion products on surface of aluminium alloy have Al, Zn and O element for all sample and within the pit was consists of Al, Zn, O and Cl element. (author)

  15. Hydrogen effects in anodic grinding of WC-Co sintered alloy

    International Nuclear Information System (INIS)

    Lunarska, E.; Zaborski, St.

    2001-01-01

    The effects of anodic polarization applied in grinding of sintered WC C o alloy on properties of surface layer, quality of ground surface and efficiency of the treatment were studied. The nonmonotonical change of the surface roughness, the energy consumption and the wear of tool was stated at increasing anodic polarization. The optimum values of above parameters were achieved at application of anodic polarization at which the Co selective dissolution and hydrogen ingress into the ground metal. affecting the internal friction spectra were stated. The assistance of hydrogen induced deterioration and Co selective dissolution in the surface layer in the anodic grinding of WC-Co alloy has been discussed. (author)

  16. Influence of alloyed Sc and Zr, and heat treatment on microstructures and stress corrosion cracking of Al–Zn–Mg–Cu alloys

    International Nuclear Information System (INIS)

    Shi, Yunjia; Pan, Qinglin; Li, Mengjia; Huang, Xing; Li, Bo

    2015-01-01

    Stress corrosion cracking (SCC) behavior of Al–Zn–Mg–Cu alloys with different Sc, Zr contents and heat treatments was studied using slow strain rate test. Grain boundary microstructures were identified by transmission electron microscopy (TEM) and statistical analysis. It was found that the SCC resistance of alloys is improved by increasing Sc, Zr contents and aging degree. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The results reveal that for Al–Zn–Mg–Cu–0.25Sc–0.10Zr (wt%) alloy with different aging degrees, hydrogen induced cracking dominates the SCC when the area fraction of GBPs is relatively low. For peak-aged Al–Zn–Mg–Cu alloy and Al–Zn–Mg–Cu–0.10Sc–0.10Zr (wt%) alloy, anodic dissolution dominates the SCC when the area fraction of GBPs is sufficiently high

  17. Microstructure and mechanical properties of Cu-Ni-Si alloys

    International Nuclear Information System (INIS)

    Monzen, Ryoichi; Watanabe, Chihiro

    2008-01-01

    The microstructure and mechanical properties of 0.1 wt.% Mg-added and Mg-free Cu-2.0 wt.% Ni-0.5 wt.% Si alloys aged at 400 deg. C have been examined. The addition of Mg promotes the formation of disk-shaped Ni 2 Si precipitates. The Cu-Ni-Si-Mg alloy exhibits higher strength and resistance to stress relaxation than the Cu-Ni-Si alloy. The higher strength or stress relaxation resistance is attributable to the reduction in inter-precipitate spacing by the Mg addition or the drag effect of Mg atoms on dislocation motion. The Cu-Ni-Si alloy with a large grain size of 150 μm shows higher stress relaxation resistance than the alloy with a small grain size of 10 μm because of a lower density of mobile dislocations in the former alloy

  18. Microstructure and mechanical properties of Cu-Ni-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Monzen, Ryoichi [Division of Innovative Technology and Science, Graduate School of Natural Science and Technology, Kanzawa University, Kakuma-machi, Kanazawa 920-1192 (Japan)], E-mail: monzen@t.kanazawa-u.ac.jp; Watanabe, Chihiro [Division of Innovative Technology and Science, Graduate School of Natural Science and Technology, Kanzawa University, Kakuma-machi, Kanazawa 920-1192 (Japan)

    2008-06-15

    The microstructure and mechanical properties of 0.1 wt.% Mg-added and Mg-free Cu-2.0 wt.% Ni-0.5 wt.% Si alloys aged at 400 deg. C have been examined. The addition of Mg promotes the formation of disk-shaped Ni{sub 2}Si precipitates. The Cu-Ni-Si-Mg alloy exhibits higher strength and resistance to stress relaxation than the Cu-Ni-Si alloy. The higher strength or stress relaxation resistance is attributable to the reduction in inter-precipitate spacing by the Mg addition or the drag effect of Mg atoms on dislocation motion. The Cu-Ni-Si alloy with a large grain size of 150 {mu}m shows higher stress relaxation resistance than the alloy with a small grain size of 10 {mu}m because of a lower density of mobile dislocations in the former alloy.

  19. Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys

    International Nuclear Information System (INIS)

    Chemin, Aline; Marques, Denys; Bisanha, Leandro; Motheo, Artur de Jesus; Bose Filho, Waldek Wladimir; Ruchert, Cassius Olivio Figueiredo

    2014-01-01

    Highlights: • The corrosion on new aerospace aluminum alloy is studied. • Al 7 Cu 2 Fe precipitate was detected in the 7475-T7351 and 7081 T73511 alloy by scanning electron microscopy. • Al 7 Cu 2 Fe particles have different morphologies depending on the forming process. • Corrosion pitting occurs around Al 7 Cu 2 Fe precipitates in 7475-T7351 and 7081-T73511 alloys. - Abstract: The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al 7 Cu 2 Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al 7 Cu 2 Fe precipitate in both alloys, revealing the anodic behavior of the matrix

  20. Long-term performance of different aluminum alloy designs as sacrificial anodes for rebars

    Directory of Open Access Journals (Sweden)

    de Rincón, O.

    2003-12-01

    Full Text Available This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermosprayed aluminum (3-year evaluation and conventional Al/Zn/In anocies in an epoxy-painted steel bracelet (12-year evaluation, indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermosprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials ( < -1100 mV vs. Cu/CuSO4 they supply to the reinforcement could lead to hydrogen embrittlement.

    Este trabajo presenta la realización de varios diseños de protección catódica utilizando aleaciones de aluminio para la protección de pilotes pretensados. Los resultados obtenidos con diferentes diseños (aleación de Al/Zn/In, tipo brazalete y aluminio termorociado (3 años de evaluación y ánodos convencionales de Al/Zn/In colocados en un brazalete de acero pintado con epoxy (12 años de evaluación, indicaron que todos estos sistemas pueden ser utilizados como ánodos de sacrificio para la protección de los pilotes. Sin embargo, el sistema con aluminio termorociado no puede ser utilizado en pilotes de acero pretensado debido al potencial muy negativo alcanzado por la armadura (<-1100 mV vs Cu/CuSO4, lo cual podría inducir a daños por hidrógeno.

  1. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung 413, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China); Wu, Chia-Ping [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Sun, Ying-Sui [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Yang, Wei-En [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung 402, Taiwan (China); Oral Medicine Center, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2014-12-05

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications.

  2. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Yang, Wei-En; Lee, Tzu-Hsin

    2014-01-01

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications

  3. Effect of Cu content on wear resistance and mechanical behavior of Ti-Cu binary alloys

    Science.gov (United States)

    Yu, Feifei; Wang, Hefeng; Yuan, Guozheng; Shu, Xuefeng

    2017-04-01

    Arc melting with nonconsumable tungsten electrode and water-cooled copper crucible was used to fabricate Ti-Cu binary alloys with different Cu contents in an argon atmosphere. The compositions and phase structures of the fabricated alloys were investigated by glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD). Nanoindentation tests through continuous stiffness measurement were then performed at room temperature to analyze the mechanical behaviors of the alloys. Results indicated that the composition of each Ti-Cu binary alloy was Ti(100- x) Cu x ( x = 43, 60, 69, and 74 at.%). The XRD analysis results showed that the alloys were composed of different phases, indicating that different Cu contents led to the variations in alloy hardness. The wear tests results revealed that elemental Cu positively affects the wear resistance properties of the Ti-Cu alloys. Nanoindentation testing results showed that the moduli of the Ti-Cu alloys were minimally changed at increasing Cu content, whereas their hardness evidently increased according to the wear test results.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Split Sn-Cu Alloys on Carbon Nanofibers by One-step Heat Treatment for Long-Lifespan Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Shen, Zhen; Hu, Yi; Chen, Renzhong; He, Xia; Chen, Yanli; Shao, Hanfeng; Zhang, Xiangwu; Wu, Keshi

    2017-01-01

    Highlights: • Spilt Sn–Cu alloys and amorphous CNF anodes are introduced. • Sn–Cu–CNFs were prepared by one-step carbonization-alloying reactions. • The spilt Sn–Cu alloys consist of Cu 6 Sn 5 and Cu 3 Sn. • The coexistence of Cu 6 Sn 5 and Cu 3 Sn led to the enhanced cycle durability. - Abstract: To develop next-generation lithium-ion batteries (LIBs) with novel designs, reconsidering traditional materials with enhanced cycle stability and excellent rate performance is crucial. We herein report the successful preparation of three-dimensional (3D) composites in which spilt Sn–Cu alloys are uniformly dispersed in an amorphous carbon nanofiber matrix (Sn–Cu–CNFs) via one-step carbonization-alloying reactions. The spilt Sn–Cu alloys consist of active Cu 6 Sn 5 and inactive Cu 3 Sn, and are controllable by optimization of the carbonization-alloying reaction temperature. The 3D carbon nanofiber framework allowed the Sn–Cu–CNFs to be used directly as anodes in lithium-ion batteries without the requirement for polymer binders or electrical conductors. These composite electrodes exhibited a stable cyclability with a discharge capacity of 400 mA h g −1 at a high current density of 1.0 A g −1 after 1200 cycles, as well as an excellent rate capability, which could be attributed to the improved electrochemical properties of the Sn–Cu–CNFs provided by the buffering effect of Cu 3 Sn and the 3D carbon nanofiber framework. This one-step synthesis is expected to be widely applicable in the targeted structural design of traditional tin-based anode materials.

  9. Electrochemical properties of rapidly solidified Si-Ti-Ni(-Cu) base anode for Li-ion rechargeable batteries

    Science.gov (United States)

    Kwon, Hye Jin; Sohn, Keun Yong; Park, Won-Wook

    2013-11-01

    In this study, rapidly solidified Si-Ti-Ni-Cu alloys have been investigated as high capacity anodes for Li-ion secondary batteries. To obtain nano-sized Si particles dispersed in the inactive matrix, the alloy ribbons were fabricated using the melt spinning process. The thin ribbons were pulverized using ball-milling to make a fine powder of ˜ 4 µm average size. Coin-cell assembly was carried out under an argon gas in a glove box, in which pure lithium was used as a counter-electrode. The cells were cycled using the galvanostatic method in the potential range of 0.01 V and 1.5 V vs. Li/Li+. The microstructure and morphology were examined using an x-ray diffractometer, Field-Emission Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy. Among the anode alloys, the Si70Ti15Ni15 electrodes had the highest discharge capacity (974.1 mAh/g) after the 50th cycle, and the Si60Ti16Ni16Cu8 electrode showed the best coulombic efficiency of ˜95.9% in cyclic behavior. It was revealed that the Si7Ni4Ti4 crystal phase coexisting with an amorphous phase, could more efficiently act as a buffer layer than the fully crystallized Si7Ni4Ti4 phase. Consequently, the electrochemical properties of the anode materials pronouncedly improved when the nano-sized primary Si particle was dispersed in the inactive Si7Ni4Ti4-based matrix mixed with an amorphous structure.

  10. Lithium alloys and metal oxides as high-capacity anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Liang, Chu; Gao, Mingxia; Pan, Hongge; Liu, Yongfeng; Yan, Mi

    2013-01-01

    Highlights: •Progress in lithium alloys and metal oxides as anode materials for lithium-ion batteries is reviewed. •Electrochemical characteristics and lithium storage mechanisms of lithium alloys and metal oxides are summarized. •Strategies for improving electrochemical lithium storage properties of lithium alloys and metal oxides are discussed. •Challenges in developing lithium alloys and metal oxides as commercial anodes for lithium-ion batteries are pointed out. -- Abstract: Lithium alloys and metal oxides have been widely recognized as the next-generation anode materials for lithium-ion batteries with high energy density and high power density. A variety of lithium alloys and metal oxides have been explored as alternatives to the commercial carbonaceous anodes. The electrochemical characteristics of silicon, tin, tin oxide, iron oxides, cobalt oxides, copper oxides, and so on are systematically summarized. In this review, it is not the scope to retrace the overall studies, but rather to highlight the electrochemical performances, the lithium storage mechanism and the strategies in improving the electrochemical properties of lithium alloys and metal oxides. The challenges and new directions in developing lithium alloys and metal oxides as commercial anodes for the next-generation lithium-ion batteries are also discussed

  11. Pitting corrosion of Al and Al-Cu alloys by ClO4- ions in neutral sulphate solutions

    International Nuclear Information System (INIS)

    Amin, Mohammed A.; Abd El Rehim, Sayed S.; Moussa, S.O.; Ellithy, Abdallah S.

    2008-01-01

    The influence of various concentrations of NaClO 4 , as a pitting corrosion agent, on the corrosion behaviour of pure Al, and two Al-Cu alloys, namely (Al + 2.5 wt% Cu) and (Al + 7 wt% Cu) alloys in 1.0 M Na 2 SO 4 solution was investigated by potentiodynamic polarization and potentiostatic techniques at 25 deg. C. Measurements were conducted under the influence of various experimental conditions, complemented by ex situ energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) examinations of the electrode surface. In free perchlorate sulphate solutions, for the three Al samples, the anodic polarization exhibits an active/passive transition. The active dissolution region involves an anodic peak (peak A) which is assigned to the formation of Al 2 O 3 passive film on the electrode surface. The passive region extends up to 1500 mV with almost constant current density (j pass ) without exhibiting a critical breakdown potential or showing any evidence of pitting attack. For the three Al samples, addition of ClO 4 - ions to the sulphate solution stimulates their active anodic dissolution and tends to induce pitting corrosion within the oxide passive region. Pitting corrosion was confirmed by SEM examination of the electrode surface. The pitting potential decreases with increasing ClO 4 - ion concentration indicating a decrease in pitting corrosion resistance. The susceptibility of the three Al samples towards pitting corrosion decreases in the order: Al > (Al + 2.5 wt% Cu) alloy > (Al + 7 wt% Cu) alloy. Potentiostatic measurements showed that the rate of pitting initiation increases with increasing ClO 4 - ion concentration and applied step anodic potential, while it decreases with increasing %Cu in the Al samples. The inhibitive effect of SO 4 2- ions was also discussed

  12. Dendrite-Free Electrodeposition and Reoxidation of Lithium-Sodium Alloy for Metal-Anode Battery

    Science.gov (United States)

    2011-11-01

    Dendrite-Free Electrodeposition and Reoxidation of Lithium-Sodium Alloy for Metal-Anode Battery Johanna K. Star 1 , Yi Ding 2 , and Paul A. Kohl ,1, * 1...Journal Article 3. DATES COVERED 01-11-2011 to 01-11-2011 4. TITLE AND SUBTITLE DENDRITE-FREE ELECTRODEPOSITION AND REOXIDATION OF LITHIUM-SODIUM...can short circuit the anode and cathode . Anode- cathode short circuits are especially dangerous when a flammable organic solvent is used as the

  13. Observations of a Cast Cu-Cr-Zr Alloy

    Science.gov (United States)

    Ellis, David L.

    2006-01-01

    Prior work has demonstrated that Cu-Cr-Nb alloys have considerable advantages over the copper alloys currently used in regeneratively cooled rocket engine liners. Observations indicated that Zr and Nb have similar chemical properties and form very similar compounds. Glazov and Zakharov et al. reported the presence of Cr2Zr in Cu-Cr-Zr alloys with up to 3.5 wt% Cr and Zr though Zeng et al. calculated that Cr2Zr could not exist in a ternary Cu-Cr-Zr alloy. A cast Cu-6.15 wt% Cr-5.25 wt% Zr alloy was examined to determine if the microstructure developed would be similar to GRCop-84 (Cu-6.65 wt% Cr-5.85 wt% Nb). It was observed that the Cu-Cr-Zr system did not form any Cr2Zr even after a thermal exposure at 875 C for 176.5 h. Instead the alloy consisted of three phases: Cu, Cu5Zr, and Cr.

  14. Cu-SnO2 nanostructures obtained via galvanic replacement control as high performance anodes for lithium-ion storage

    Science.gov (United States)

    Nguyen, Tuan Loi; Park, Duckshin; Hur, Jaehyun; Son, Hyung Bin; Park, Min Sang; Lee, Seung Geol; Kim, Ji Hyeon; Kim, Il Tae

    2018-01-01

    SnO2 has been considered as a promising anode material for lithium ion batteries (LIBs) because of its high theoretical capacity (782 mAh g-1). However, the reaction between lithium ions and Sn causes a large volume change, resulting in the pulverization of the anode, a loss of contact with the current collector, and a deterioration in electrochemical performance. Several strategies have been proposed to mitigate the drastic volume changes to extend the cyclic life of SnO2 materials. Herein, novel composites consisting of Cu and SnO2 were developed via the galvanic replacement reaction. The reaction was carried out at 180 °C for different durations and triethylene glycol was used as the medium solvent. The structure, morphology, and composition of the composites were analyzed by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The reaction time affected the particle size, which in turn affected the reaction kinetics. Furthermore, the novel nanostructures contained an inactive metal phase (Cu), which acted both as the buffer space against the volume change of Sn during the alloying reaction and as the electron conductor, resulting in a lower impedance of the composites. When evaluated as potential anodes for LIBs, the composite electrodes displayed extraordinary electrochemical performance with a high capacity and Coulombic efficiency, an excellent cycling stability, and a superior rate capability compared to a Sn electrode.

  15. Environmental friendly anodizing of AZ91D magnesium alloy in alkaline borate-benzoate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yan [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Department of Chemistry, Tianshui Normal University, Tianshui 741000 (China); Wei Zhongling [Magnesium Technology Co., Ltd., Chinese Academy of Sciences, Jiaxing 314051 (China); Yang Fuwei [Department of Chemistry, Tianshui Normal University, Tianshui 741000 (China); Zhang Zhao, E-mail: eaglezzy@zjuem.zju.edu.cn [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Key Laboratory for Light Alloy Materials Technology, Jiaxing 314051 (China)

    2011-06-02

    Highlights: > Environmental friendly PEO technology for AZ91 magnesium alloy is developed. > NaBz is used as new additive and it is low-cost and environmental friendly. > The effect of NaBz additive on the properties of the anodized film was studied. > Anodized film with excellent corrosion resistance is obtained. > The forming mechanism of anodized film in the presence of NaBz is approached. - Abstract: A kind of environmental friendly anodizing routine for AZ91D magnesium alloy, based on an alkaline borate-sodium benzoate electrolyte (NaBz) was studied. The effect of NaBz on the properties of the anodized film was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), respectively. The results showed that the anodizing process, surface morphology, thickness, phase structure and corrosion resistance of the anodized film were strongly dependent on the concentration of NaBz. In the presence of adequate NaBz, a thick, compact and smoothing anodized film with excellent corrosion resistance was produced. Moreover, the forming mechanism of the anodized film in the presence of NaBz additive was also approached, which was a suppression of arc discharge process by the adsorption of Bz{sup -} on the surface of magnesium alloy substrate.

  16. Environmental friendly anodizing of AZ91D magnesium alloy in alkaline borate-benzoate electrolyte

    International Nuclear Information System (INIS)

    Liu Yan; Wei Zhongling; Yang Fuwei; Zhang Zhao

    2011-01-01

    Highlights: → Environmental friendly PEO technology for AZ91 magnesium alloy is developed. → NaBz is used as new additive and it is low-cost and environmental friendly. → The effect of NaBz additive on the properties of the anodized film was studied. → Anodized film with excellent corrosion resistance is obtained. → The forming mechanism of anodized film in the presence of NaBz is approached. - Abstract: A kind of environmental friendly anodizing routine for AZ91D magnesium alloy, based on an alkaline borate-sodium benzoate electrolyte (NaBz) was studied. The effect of NaBz on the properties of the anodized film was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), respectively. The results showed that the anodizing process, surface morphology, thickness, phase structure and corrosion resistance of the anodized film were strongly dependent on the concentration of NaBz. In the presence of adequate NaBz, a thick, compact and smoothing anodized film with excellent corrosion resistance was produced. Moreover, the forming mechanism of the anodized film in the presence of NaBz additive was also approached, which was a suppression of arc discharge process by the adsorption of Bz - on the surface of magnesium alloy substrate.

  17. Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy

    Science.gov (United States)

    Li, Song-mei; Li, Ying-dong; Zhang, You; Liu, Jian-hua; Yu, Mei

    2015-02-01

    Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.

  18. CuO nanorods/graphene nanocomposites for high-performance lithium-ion battery anodes

    International Nuclear Information System (INIS)

    Wang, Qi; Zhao, Jun; Shan, Wanfei; Xia, Xinbei; Xing, Lili; Xue, Xinyu

    2014-01-01

    Highlights: • CuO/GNS nanocomposites are synthesized by a hydrothermal method. • CuO/GNSs as LIB anodes exhibit much higher cyclability and capacity than CuO nanostructures. • Such excellent performances can be attributed to the synergistic effect between CuO and GNSs. -- Abstract: CuO/graphene nanocomposites are synthesized by a hydrothermal method, and their application as anodes of lithium-ion batteries has been investigated. CuO nanorods are uniformly coating on the surface of graphene nanosheets. CuO/graphene nanocomposites exhibit high cyclability and capacity. After 50 cycles, the capacity can maintain at 692.5 mA h g −1 at 0.1 C rate (10 h per half cycle). Such a high performance can be attributed to the synergistic effect between graphene nanosheets and CuO nanorods. The present results indicate that CuO/graphene nanocomposites have potential applications in the anodes of lithium-ion battery

  19. Characterization and Tribological Properties of Hard Anodized and Micro Arc Oxidized 5754 Quality Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    M. Ovundur

    2015-03-01

    Full Text Available This study was initiated to compare the tribological performances of a 5754 quality aluminum alloy after hard anodic oxidation and micro arc oxidation processes. The structural analyses of the coatings were performed using XRD and SEM techniques. The hardness of the coatings was determined using a Vickers micro-indentation tester. Tribological performances of the hard anodized and micro arc oxidized samples were compared on a reciprocating wear tester under dry sliding conditions. The dry sliding wear tests showed that the wear resistance of the oxide coating generated by micro arc oxidation is remarkably higher than that of the hard anodized alloy.

  20. 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.

  1. Coupled growth of Al-Al2Cu eutectics in Al-Cu-Ag alloys

    International Nuclear Information System (INIS)

    Hecht, U; Witusiewicz, V; Drevermann, A

    2012-01-01

    Coupled eutectic growth of Al and Al 2 Cu was investigated in univariant Al-Cu-Ag alloys during solidification with planar and cellular morphology. Experiments reveal the dynamic selection of small spacings, below the minimum undercooling spacing and show that distinct morphological features pertain to nearly isotropic or anisotropic Al-Al 2 Cu interfaces.

  2. The electrochemical properties and mechanism of formation of anodic oxide films on Mg-Al alloys

    International Nuclear Information System (INIS)

    Kim, Seong Jong; Okido, Masazumi

    2003-01-01

    The electronchemical properties and the mechanism of formation of anodic oxide films on Mg alloys containing 0-15 mass% Al, when anodized in NaOH solution, were investigated by focusing on the effects of anodizing potential, Al content, and anodizing time. The intensity ratio of Mg(OH) 2 in the XRD analysis decreased with increasing applied potential, while that of MgO increased. Mg(OH) 2 was barely detected at 80 V, while MgO was readily detected. The anti-corrosion properties of anodized specimens at each constant potential were better than those of non-anodized specimens. The specimen anodized at an applied potential of 3 V had the best anti-corrosion property. The intensity ratio of the β phase increased with aluminum content in Mg-Al alloys. During anodizing, the active dissolution reaction occurred preferentially in β phase until about 4 min, and then the current density increased gradually until 7 min. The dissolution reaction progressed in α phase, which had a lower Al content. In the anodic polarization test in 0.017 mol·dm -3 NaCl and 0.1 mol·dm -3 Na 2 SO 4 at 298 K, the current density of Mg-15 mass% Al alloy anodized for 10 min increased, since the anodic film that forms on the α phase is a non-compacted film. The anodic film on the α phase at 30 min was a compact film as compared with that at 10 min

  3. The electrochemical properties and mechanism of formation of anodic oxide films on Mg-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Jong; Okido, Masazumi [Nagoya Univ., Nagoya (Japan)

    2003-07-01

    The electronchemical properties and the mechanism of formation of anodic oxide films on Mg alloys containing 0-15 mass% Al, when anodized in NaOH solution, were investigated by focusing on the effects of anodizing potential, Al content, and anodizing time. The intensity ratio of Mg(OH){sub 2} in the XRD analysis decreased with increasing applied potential, while that of MgO increased. Mg(OH){sub 2} was barely detected at 80 V, while MgO was readily detected. The anti-corrosion properties of anodized specimens at each constant potential were better than those of non-anodized specimens. The specimen anodized at an applied potential of 3 V had the best anti-corrosion property. The intensity ratio of the {beta} phase increased with aluminum content in Mg-Al alloys. During anodizing, the active dissolution reaction occurred preferentially in {beta} phase until about 4 min, and then the current density increased gradually until 7 min. The dissolution reaction progressed in {alpha} phase, which had a lower Al content. In the anodic polarization test in 0.017 mol{center_dot}dm{sup -3} NaCl and 0.1 mol{center_dot}dm{sup -3} Na{sub 2}SO{sub 4} at 298 K, the current density of Mg-15 mass% Al alloy anodized for 10 min increased, since the anodic film that forms on the {alpha} phase is a non-compacted film. The anodic film on the {alpha} phase at 30 min was a compact film as compared with that at 10 min.

  4. Corrosion resistance of plasma-anodized AZ91D magnesium alloy by electrochemical methods

    International Nuclear Information System (INIS)

    Barchiche, C.-E.; Rocca, E.; Juers, C.; Hazan, J.; Steinmetz, J.

    2007-01-01

    Anodic coatings formed on magnesium alloys by plasma anodization process are mainly used as protective coatings against corrosion. The effects of KOH concentration, anodization time and current density on properties of anodic layers formed on AZ91D magnesium alloy were investigated to obtain coatings with improved corrosion behaviour. The coatings were characterized by scanning electron microscopy (SEM), electron dispersion X-ray spectroscopy (EDX), X-ray diffraction (XRD) and micro-Raman spectroscopy. The film is porous and cracked, mainly composed of magnesium oxide (MgO), but contains all the elements present in the electrolyte and alloy. The corrosion behaviour of anodized Mg alloy was examined by using stationary and dynamic electrochemical techniques in corrosive water. The best corrosion resistance measured by electrochemical methods is obtained in the more concentrated electrolyte 3 M KOH + 0.5 M KF + 0.25 M Na 3 PO 4 .12 H 2 O, with a long anodization time and a low current density. A double electrochemical effects of the anodized layer on the magnesium corrosion is observed: a large inhibition of the cathodic process and a stabilization of a large passivation plateau

  5. Fragility and structure of Al-Cu alloy melts

    International Nuclear Information System (INIS)

    Lv Xiaoqian; Bian Xiufang; Mao Tan; Li Zhenkuan; Guo Jing; Zhao Yan

    2007-01-01

    The dynamic viscosity measurements are performed for Al-Cu alloy melts with different compositions using an oscillating-cup viscometer. The results show that the viscosities of Al-Cu alloy melts increase with the copper content increasing, and also have a correlation with the correlation radius of clusters, which is measured by the high-temperature X-ray diffractometer. It has also been found that the fragilities of superheated melts (M) of hypereutectic Al-Cu alloys increase with the copper content increasing. There exists a relationship between the fragility and the structure in Al-Cu alloy melts. The value of the M reflects the variation of activation energy for viscous flow

  6. Moessbauer spectroscopy of Fe-Mn-Cu alloys

    International Nuclear Information System (INIS)

    Paduani, Clederson; Krause, Joao Carlos; Yoschida, M.I. Soares

    2004-01-01

    Full text: Although a continuous series of solid solutions exists between Cu and Mn, Fe and Cu are miscible only a few percent at higher temperatures. In moderately concentrated Cu-Mn alloys the Mn moments are bound to the long ranged antiferromagnetic order and the perpendicular components form an X-Y spin glass. Copper alloys are largely employed in various industrial applications. In this work we study the magnetic properties of iron-rich disordered Fe-Mn-Cu alloys with the bcc structure with the experimental techniques of X-ray diffraction (XRD), Moessbauer spectroscopy (MS) and thermogravimetry (TGA). We investigate the formation of a solid solution with the bcc structure as well as the effect of the composition on the structural and magnetic properties of these alloys. A Rietveld analysis of the XRD diffractograms indicate that all prepared samples are single phase and are well crystallized with a bcc structure. (author)

  7. Time evolution of morphology in mechanically alloyed Fe-Cu

    KAUST Repository

    Wille, Catharina Gabriele; Al-Kassab, Talaá t; Kirchheim, Reiner

    2011-01-01

    Being widely accessible as well as already utilised in many applications, Fe-Cu acts as an ideal binary model alloy to elaborate the enforced nonequilibrium enhanced solubility in such a solution system that shows a limited regime of miscibility

  8. Performance of lithium alloy/lithium and calcium/lithium anodes in thionyl chloride cells

    Energy Technology Data Exchange (ETDEWEB)

    Keister, P.; Greenwood, J.M.; Holmes, C.F.; Mead, R.T.

    1985-08-01

    A laminar composite anode construction comprising an inner metal completely surrounded by Li foil was studied as a means of obtaining an end-of-life indicator in a thionyl chloride cell. Inner metals of Ca, 14-2.9 at.% Ca in Li alloys, and 6.7-2.1 at.% Mg in Li alloys were evaluated. Discharge characteristics of cells using these sandwich anodes as well as cells containing the inner anode material alone were determined. It was concluded that cells made with inner anode materials of Ca and Ca/Li alloys containing more than 7 at.% Ca showed promise as a means of obtaining a reliable end-of-life indication. (orig.).

  9. Development of amorphous and nanocrystalline Al65Cu35-xZrx alloys by mechanical alloying

    International Nuclear Information System (INIS)

    Manna, I.; Chattopadhyay, P.P.; Banhart, F.; Fecht, H.J.

    2004-01-01

    Mechanical alloying of Al 65 Cu 35-x Zr x (x=5, 15 and 25 at.% Zr) elemental powder blends by planetary ball milling up to 50 h yields amorphous and/or nanocrystalline products. Microstructure of the milled product at different stages of milling has been characterized by X-ray diffraction, (XRD) high-resolution transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Among the different alloys synthesized by mechanical alloying, Al 65 Cu 20 Zr 15 yields a predominantly amorphous product, while the other two alloys develop a composite microstructure comprising nanocrystalline and amorphous solid solutions in Al 65 Cu 10 Zr 25 and nano-intermetallic phase/compound in Al 65 Cu 30 Zr 5 , respectively. The genesis of solid-state amorphization in Al 65 Cu 20 Zr 15 and Al 65 Cu 10 Zr 25 is investigated

  10. Investigation of cerium salt/sulfuric acid anodizing technology for 1420 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Di Li; Yue Peng Deng; Bao Lan Guo; Guo Qiang Li [Beijing Univ. of Aeronautics and Astronautics (China). Dept. of Mater. Sci. and Eng.

    2000-07-01

    In this paper, the effect of cerium addition agent on the property of anodized coating of 1420 Al alloy has been studied by corrosion experiment (immersion test and neutral salt spray test), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and measurement of polarization curves. The result show that only pitting could be observed in all corrosion tests while intergranular corrosion and exfoliation corrosion did not appear on 1420 Al-Li alloys. When organic carboxylic acid S or the cerium (IV) salt was added into sulfuric acid anodizing electrolyte separately, there was no significant improvement in corrosion resistance of anodized film. However, in the case of adding them into sulfuric acid anodizing electrolyte together, the corrosion resistance of anodized film increased greatly owing to synergistic effect. The synergistic effect may relate to the formation of cerium-organic carboxylic acid S complex compound and its effects on film growth and film structure. (orig.)

  11. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    Science.gov (United States)

    Liu, Wenyong; Luo, Yuting; Sun, Linyu; Wu, Ruomei; Jiang, Haiyun; Liu, Yuejun

    2013-01-01

    We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low surface free energy, the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  12. 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

  13. Photo-electrochemical and impedance investigation of passive layers grown anodically on titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, N.T.C. [Departamento de Quimica, Universidade Federal de Sao Carlos, CP 676, 13560-970 Sao Carlos, SP (Brazil); Biaggio, S.R. [Departamento de Quimica, Universidade Federal de Sao Carlos, CP 676, 13560-970 Sao Carlos, SP (Brazil); Piazza, S. [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)]. E-mail: piazza@dicpm.unipa.it; Sunseri, C. [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Di Quarto, F. [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2004-10-15

    The anodic behaviour of two titanium cast alloys, obtained by fusion in a voltaic arc under argon atmosphere, was analyzed in aerated aqueous solutions having different pH values. In all solutions the alloys, having nominal compositions Ti-50Zr at.% and Ti-13Zr-13Nb wt.%, displayed a valve-metal behaviour, owing to the formation of barrier-type oxide films. Passive films, grown potentiodynamically up to about 9 V, were investigated by photocurrent spectroscopy (PCS) and electrochemical impedance spectroscopy (EIS). These passive layers show photoactivity under anodic polarizations, with optical gaps close to 3.55 and 3.25 eV for the binary and the ternary alloy, respectively, independent of the anodizing electrolyte. Films grown on the binary alloy present insulating behaviour and anodic impedance spectra with one time constant; this was interpreted in terms of a single-layer mixed Ti-Zr oxide enriched in Ti with respect to the alloy composition. Also for the ternary alloy the results are consistent with the formation, upon anodization, of Ti-Nb-Zr mixed oxide films, but they display n-type semiconducting behaviour, owing to their poor content of ZrO{sub 2} groups.

  14. Study of Shell Zone Formation in Lithographic and Anodizing Quality Aluminum Alloys: Experimental and Numerical Approach

    Science.gov (United States)

    Brochu, Christine; Larouche, André; Hark, Robert

    Shell thickness is an important quality factor for lithographic and anodizing quality aluminum alloys. Increasing pressure is placed on casting plants to produce a thinner shell zone for these alloys. This study, based on plant trials and mathematical modelling highlights the most significant parameters influencing shell zone formation. Results obtained show the importance of metal temperature and distribution and mould metal level on shell zone formation. As an answer to specific plant problems, this study led to the development of improved metal distribution systems for DC casting of litho and anodizing quality alloys.

  15. 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....

  16. 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

  17. 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.

  18. Interfacial properties of immiscible Co-Cu alloys

    DEFF Research Database (Denmark)

    Egry, I.; Ratke, L.; Kolbe, M.

    2010-01-01

    Using electromagnetic levitation under microgravity conditions, the interfacial properties of an Cu75Co25 alloy have been investigated in the liquid phase. This alloy exhibits a metastable liquid miscibility gap and can be prepared and levitated in a configuration consisting of a liquid cobalt-ri...

  19. Corrosion behavior of cast Ti-6Al-4V alloyed with Cu.

    Science.gov (United States)

    Koike, Marie; Cai, Zhuo; Oda, Yutaka; Hattori, Masayuki; Fujii, Hiroyuki; Okabe, Toru

    2005-05-01

    It has recently been found that alloying with copper improved the inherently poor grindability and wear resistance of titanium. This study characterized the corrosion behavior of cast Ti-6Al-4V alloyed with copper. Alloys (0.9 or 3.5 mass % Cu) were cast with the use of a magnesia-based investment in a centrifugal casting machine. Three specimen surfaces were tested: ground, sandblasted, and as cast. Commercially pure titanium and Ti-6Al-4V served as controls. Open-circuit potential measurement, linear polarization, and potentiodynamic cathodic polarization were performed in aerated (air + 10% CO(2)) modified Tani-Zucchi synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was conducted in the same medium deaerated by N(2) + 10% CO(2). Polarization resistance (R(p)), Tafel slopes, and corrosion current density (I(corr)) were determined. A passive region occurred for the alloy specimens with ground and sandblasted surfaces, as for CP Ti. However, no passivation was observed on the as-cast alloys or on CP Ti. There were significant differences among all metals tested for R(p) and I(corr) and significantly higher R(p) and lower I(corr) values for CP Ti compared to Ti-6Al-4V or the alloys with Cu. Alloying up to 3.5 mass % Cu to Ti-6Al-4V did not change the corrosion behavior. Specimens with ground or sandblasted surfaces were superior to specimens with as-cast surfaces. (c) 2005 Wiley Periodicals, Inc.

  20. Study of properties of Cu-Y and Cu-Y-Al system alloys

    International Nuclear Information System (INIS)

    Shparo, N.B.; Nikolaev, A.K.; Rozenberg, V.M.

    1978-01-01

    Investigated were the strength properties of alloys Cu(0-1.2)% Y and Cu-(10-0.5)% Al-(0-0.5)% Y after being treated under various heat conditions and tested at temperatures of 20, 400 and 600 deg C. Yttrium additions raise the temperature of recrystallization of copper and of copper-aluminium alloys. Small additions of yttrium (0.05%) increase considerably strength of Cu-Al alloys without increasing their electric resistance. Optimum properties are attained after hardening, deformation and ageing at 400 deg C

  1. Role of Ca in Modifying Corrosion Resistance and Bioactivity of Plasma Anodized AM60 Magnesium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Anawati, Anawati; Asoh, Hidetaka; Ono, Sachiko [Kogakuin University, Tokyo (Japan)

    2016-06-15

    The effect of alloying element Ca (0, 1, and 2 wt%) on corrosion resistance and bioactivity of the as-received and anodized surface of rolled plate AM60 alloys was investigated. A plasma electrolytic oxidation (PEO) was carried out to form anodic oxide film in 0.5 mol dm{sup -3} Na{sub 3}PO{sub 4} solution. The corrosion behavior was studied by polarization measurements while the in vitro bioactivity was tested by soaking the specimens in Simulated Body Fluid (1.5xSBF). Optical micrograph and elemental analysis of the substrate surfaces indicated that the number of intermetallic particles increased with Ca content in the alloys owing to the formation of a new phase Al2Ca. The corrosion resistance of AM60 specimens improved only slightly by alloying with 2 wt% Ca which was attributed to the reticular distribution of Al2Ca phase existed in the alloy that might became barrier for corrosion propagation across grain boundaries. Corrosion resistance of the three alloys was significantly improved by coating the substrates with anodic oxide film formed by PEO. The film mainly composed of magnesium phosphate with thickness in the range 30 - 40 μm. The heat resistant phase of Al{sub 2}Ca was believed to retard the plasma discharge during anodization and, hence, decreased the film thickness of Ca-containing alloys. The highest apatite forming ability in 1.5xSBF was observed for AM60-1Ca specimens (both substrate and anodized) that exhibited more degradation than the other two alloys as indicated by surface observation. The increase of surface roughness and the degree of supersaturation of 1.5xSBF due to dissolution of Mg ions from the substrate surface or the release of film compounds from the anodized surface are important factors to enhance deposition of Ca-P compound on the specimen surfaces.

  2. Phase transformations in the Cu.6 Pd.4 alloy

    International Nuclear Information System (INIS)

    Imakuma, K.

    1977-01-01

    Order-disorder and structural transformations in the Cu-Pd 60-40% (Cu. 6 Pd. 4 ) alloy by means of a temperature and time dependent treatment are studied. The structural transformations by x-rays diffraction are also studied, where the bcc, fcc and tetragonal phases were observed. A qualitative analyze of the resistivity kinetics are made [pt

  3. Anodizing of magnesium alloy AZ31 in alkaline solutions with silicate under continuous sparking

    International Nuclear Information System (INIS)

    Chai Liyuan; Yu Xia; Yang Zhihui; Wang Yunyan; Okido, Masazumi

    2008-01-01

    Anodization is a useful technique for forming protective films on magnesium alloys and improves its corrosion resistance. Based on the alkaline electrolyte solution with primary oxysalt developed previously, the optimum secondary oxysalt was selected by comparing the anti-corrosion property of anodic film. The structure, component and surface morphology of anodic film and cross-section were analyzed using energy dispersion spectrometer (EDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion process was detected by electrochemical impedance spectroscopy (EIS). The results showed that secondary oxysalt addition resulted in different anodizing processes, sparking or non-sparking. Sodium silicate was the most favorable additive of electrolyte, in which anodic film with the strongest corrosion resistance was obtained. The effects of process parameters, such as silicate concentration, applied current density and temperature, were also investigated. High temperature did not improve anti-property of anodic film, while applying high current density resulted in more porous surface of film

  4. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    Energy Technology Data Exchange (ETDEWEB)

    Liu Wenyong, E-mail: lwy@iccas.ac.cn [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Luo Yuting; Sun Linyu [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Wu Ruomei, E-mail: cailiaodian2004@126.com [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Jiang Haiyun [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Liu Yuejun [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China)

    2013-01-01

    Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: Black-Right-Pointing-Pointer Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. Black-Right-Pointing-Pointer Superhydrophobic surfaces with a high water contact angle of 162 Degree-Sign and a low rolling angle of 2 Degree-Sign were obtained. Black-Right-Pointing-Pointer The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162 Degree-Sign and the sliding angle of 2 Degree-Sign was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed

  5. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    International Nuclear Information System (INIS)

    Liu Wenyong; Luo Yuting; Sun Linyu; Wu Ruomei; Jiang Haiyun; Liu Yuejun

    2013-01-01

    Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: ► Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. ► Superhydrophobic surfaces with a high water contact angle of 162° and a low rolling angle of 2° were obtained. ► The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low

  6. The influence of Ti and Sr alloying elements on electrochemical properties of aluminum sacrificial anodes

    Energy Technology Data Exchange (ETDEWEB)

    Saremi, M.; Sina, H.; Keyvani, A.; Emamy, M. [Metallurgy and Materials Department, University of Tehran, P.O. Box 11365/4563, Tehran (Iran)

    2004-07-01

    Aluminum sacrificial anodes are widely used in cathodic protection of alloys in seawater. The interesting properties due to low specific weight, low electrode potential and high current capacity are often hindered by the presence of a passive oxide film which causes several difficulties in their practical application. In this investigation, the electrochemical behavior of Al- 5Zn-0.02In sacrificial anode is studied in 3 wt. % sodium chloride solution. The experiments focused on the influence of Ti and Sr as alloying elements on electrochemical behavior of aluminum sacrificial anode. Ti and Sr are used in different concentrations from 0.03 to 0.1 wt.% 0.01 to 0.05 wt.%, respectively. NACE efficiency and polarization tests are used in this case. It is shown that by using 0.03 wt.% Ti and 0.01 wt.% Sr as the alloying elements to investigate the anodic behavior of the anodes, homogeneous microstructures are obtained which results in improvement of electrochemical properties of aluminum sacrificial anode such as current capacity and anode efficiency. (authors)

  7. Electroless Cu Plating on Anodized Al Substrate for High Power LED.

    Science.gov (United States)

    Rha, Sa-Kyun; Lee, Youn-Seoung

    2015-03-01

    Area-selective copper deposition on screen printed Ag pattern/anodized Al/Al substrate was attempted using a neutral electroless plating processes for printed circuit boards (PCBs), according to a range of variation of pH 6.5-pH 8 at 70 °C. The utilized basic electroless solution consisted of copper(II) sulfate pentahydrate, sodium phosphinate monohydrate, sodium citrate tribasic dihydrate, ammonium chloride, and nickel(II) sulfate hexahydrate. The pH of the copper plating solutions was adjusted from pH 6.5 to pH 8 using NH4OH. Using electroless plating in pH 6.5 and pH 7 baths, surface damage to the anodized Al layer hardly occurred; the structure of the plated Cu-rich films was a typical fcc-Cu, but a small Ni component was co-deposited. In electroless plating at pH 8, the surface of the anodized Al layer was damaged and the Cu film was composed of a lot of Ni and P which were co-deposited with Cu. Finally, in a pH 7 bath, we can make a selectively electroless plated Cu film on a PCB without any lithography and without surface damage to the anodized Al layer.

  8. Anodic characteristics and stress corrosion cracking behavior of nickel rich alloys in bicarbonate and buffer solutions

    International Nuclear Information System (INIS)

    Zadorozne, Natalia S.; Giordano, Mabel C.; Ares, Alicia E.; Carranza, Ricardo M.; Rebak, Raul B.

    2016-01-01

    Highlights: • We investigate which element in alloy C-22 may be responsible for the cracking susceptibility of the high nickel alloy. • Six nickel based alloys with different amount of Cr and Mo were selected for the electrochemical tests and response to SSRT. • Polarization tests showed that an anodic peak appear in the passive region in Cr containing alloys. • Cracking of Ni alloys in carbonate solutions seem to be a consequence of the instability of the passivating chromium oxide. • Alloys containing both Cr and Mo have the highest susceptibility. - Abstract: The aim of this work is to investigate which alloying element in C-22 is responsible for the cracking susceptibility of the alloy in bicarbonate and two buffer solutions (tungstate and borate). Six nickel based alloys, with different amount of chromium (Cr) and molybdenum (Mo) were tested using electrochemical methods and slow strain rate tests (SSRT) at 90 °C. All Cr containing alloys had transgranular cracking at high anodic potential; however, C-22 containing high Cr and high Mo was the most susceptible alloy to cracking. Bicarbonate was the most aggressive of three tested environments of similar pH.

  9. Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying

    DEFF Research Database (Denmark)

    Canulescu, Stela; Rechendorff, K.; Borca, C. N.

    2014-01-01

    The band structure of pure and Ti-alloyed anodic aluminum oxide has been examined as a function of Ti concentration varying from 2 to 20 at. %. The band gap energy of Ti-alloyed anodic Al oxide decreases with increasing Ti concentration. X-ray absorption spectroscopy reveals that Ti atoms...... are not located in a TiO2 unit in the oxide layer, but rather in a mixed Ti-Al oxide layer. The optical band gap energy of the anodic oxide layers was determined by vacuum ultraviolet spectroscopy in the energy range from 4.1 to 9.2 eV (300–135 nm). The results indicate that amorphous anodic Al2O3 has a direct...

  10. Hot mechanical behaviour of dispersion strengthened Cu alloys

    International Nuclear Information System (INIS)

    Garcia G, Jose; Espinoza G, Rodrigo; Palma H, Rodrigo; Sepulveda O, Aquiles

    2003-01-01

    This work is part of a research project which objective is the improvement of the high-temperature mechanical properties of copper, without an important decrease of the electrical or thermal conduction properties. The general hypothesis is that this will be done by the incorporation of nanometric ceramic dispersoids for hindering the dislocation and grain boundaries movement. In this context, the object of the present work is the study of the resistance to hot deformation of dispersion-strengthened copper alloys which have prepared by reactive milling. Two different alloys, Cu-2,39wt.%Ti-0.56wt.%C and Cu-1.18wt.%Al, were prepared so as obtain a copper matrix reinforced with nanometric TiC y Al 2 O 3 particles with a nominal total amount of 5 vol.%. The particles were developed by an in-situ formation process during milling. The materials were prepared in an attritor mill, and consolidated by extrusion at 750 o C, with an area reduction rate of 10:1. The resistance to hot deformation was evaluated by hot compression tests at 500 and 850 o C, at initial strain rates of 10 -3 and 10 -4 s-1. To evaluate the material softening due temperature, annealing at 400, 650 y 900 o C during 1h were applied; after that, hardness was measured at room temperature. Both studies alloys presented a higher resistance to hot deformation than pure copper, with or without milling. Moreover, the Cu-Ti-C alloy presented a mechanical resistance higher than that of the Cu-Al one. Both alloys presented strain-stress compression curves with a typical hot-work shape: an initial maximum followed by a stationary plateau. The Cu-Ti-C alloy had a higher hardness and did not present a hardness decay even after annealings at the higher temperature imposed (900 o C), while the Cu-Al alloy did exhibit a strong decay of hardness after the annealing at 900 o C. The best behaviour exhibited by the Cu-Ti C alloy, was attributed to the formation of a major quantity of dispersoids that in the Cu-Al alloy. In

  11. The Paramagnetism of Small Amounts of Mn Dissolved in Cu-Al and Cu-Ge Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Myers, H P; Westin, R

    1963-06-15

    Previous measurements of the valency of Mn in Cu-Zn alloys have been confirmed by measurements with the isoelectronic Cu-Al and Cu-Ge alloys as matrices for Mn. The valency, having the value i in pure copper, decreases slightly with increasing electron to atom ratio attaining the values 0. 9 and 0. 8 at the limiting composition in the Al and Ge alloys respectively. The apparent size of Mn in these alloys is discussed.

  12. The Paramagnetism of Small Amounts of Mn Dissolved in Cu-Al and Cu-Ge Alloys

    International Nuclear Information System (INIS)

    Myers, H.P.; Westin, R.

    1963-06-01

    Previous measurements of the valency of Mn in Cu-Zn alloys have been confirmed by measurements with the isoelectronic Cu-Al and Cu-Ge alloys as matrices for Mn. The valency, having the value i in pure copper, decreases slightly with increasing electron to atom ratio attaining the values 0. 9 and 0. 8 at the limiting composition in the Al and Ge alloys respectively. The apparent size of Mn in these alloys is discussed

  13. 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.

  14. 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.

  15. The effect of different aluminum alloy surface compositions on barrier anodic film formation

    International Nuclear Information System (INIS)

    Panitz, J.K.G.; Sharp, D.J.

    1984-01-01

    The authors have grown barrier anodic coatings on samples of aluminum alloy with different elemental surface compositions. In one series of experiments, they characterized the surface composition present on 6061 aluminum alloy samples after different chemical treatments including a detergent-water and methyl-ethyl ketone solvent clean, a 50% nitric acid-water etch, and a concentrated nitric acid-ammonium bifluoride etch. They anodized samples which were prepared similarly to those analyzed to evaluate the practical effects of the three different surface compositions. The anodization voltage rise time to 950V at constant current was used as a figure of merit. The solvent cleaned and the 50% nitric acid etched samples required, respectively, 113% and 41% more time to reach 950V than the concentrated nitric acidammonium bifloride etched samples. In a second series of experiments, they alternately anodized groups of either 6061 or 1100 (commercially pure) aluminum alloy, observed rise times to 950V, and measured chloride ion concentrations in the electrolyte. Longer rise times and higher chloride ion concentrations were observed for the 1100 samples. It was observed that the chloride ion concentration fell from initially high levels when 6061 samples were anodized. The results of both series of experiments augment the results of other investigators, who report that the surface species initially present on aluminum have a significant effect on anodic film formation

  16. 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.

  17. Recycled hierarchical tripod-like CuCl from Cu-PCB waste etchant for lithium ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Song [Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 China (China); Hou, Hongying, E-mail: hongyinghou@kmust.edu.cn [Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 China (China); Liu, Xianxi [Faculty of Mechanical and Electronic Engineering, Kunming University of Science and Technology, Kunming 650093 China (China); Duan, Jixiang; Yao, Yuan; Liao, Qishu; Li, Jing; Yang, Yunzhen [Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 China (China)

    2017-02-15

    Highlights: • High EVA CuCl was recycled with 85% recovery from Cu-PCB waste etchant. • The recycled CuCl displayed a hierarchical tripod-like morphology. • The evolution mechanism of the recycled hierarchical CuCl crystal was proposed. • The corresponding discharge capacity in LIB was 201.4 mAh/g after 100 cycles. • The results shed a new light on resource recovery and environmental protection. - Abstract: Hierarchical CuCl with high economic value added (EVA) was successfully recycled with 85% recovery from the acid Cu printed circuit board (Cu-PCB) waste etchant via facile liquid chemical reduction. The micro-structure and morphology of the recycled hierarchical CuCl were systematically characterized in terms of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Furthermore, the corresponding electrochemical performances as lithium ion battery (LIB) anode were also investigated in terms of galvanostatic charge/discharge, cyclic voltammetry (CV) and AC impedance. As expected, the recycled CuCl displayed a hierarchical tripod-like structure and large specific surface area of 21.2 m{sup 2}/g. As the anode in LIB, the reversible discharge capacity was about 201.4 mAh/g even after 100 cycles, implying the satisfactory cycle performance. Clearly, the satisfactory results may open a new avenue to develop the sustainable industry, which is very important in terms of both the resource recovery and the environmental protection.

  18. Influence of aging at 200 C on the corrosion resistance of Al-Li and AI-Li-Cu alloys

    International Nuclear Information System (INIS)

    Kumai, C.; Kusinski, J.; Devine, T.M.

    1989-01-01

    This paper presents an investigation of the influence of heat treatment on the microstructure and corrosion resistance of an aluminum lithium alloy and two aluminum-lithium-copper alloys. Aging the Al-Li alloy resulted in the precipitation of δ with precipitate-free zone (PFZ) formation along the grain boundaries. The intragranular precipitation of δ did not influence either the morphology of pitting or the magnitude of the pitting potential. Pits appeared to consist of aggregates of submicron-sized cuboidal volumes. Their faceted shape suggests the strong influence of crystallographic factors. Anodic polarization of the Al-Li-Cu alloy is the T8 condition in aqueous solutions containing chloride ions resulted in blistering of the passive film and the formation of pits that were hemispherical in shape. Aging the Al-Li-Cu resulted in the precipitation of Cu-rich phases with PFZ formation along the grain and subgrain boundaries. Energy dispersive x-ray (EDX) microchemical analyses indicated the PFZ was depleted of copper. Anodic polarization of aged samples in chloride ion media resulted in localized attack along the subgrain and grain boundaries. Such attack did not occur in solutions free of chloride ions. The electrochemical tests and microchemical analyses suggest that the boundary corrosion was caused by the pitting corrosion of copper-depleted zones

  19. Microalloying with Cd of Antifriction Sn-Sb-Cu Alloys

    Directory of Open Access Journals (Sweden)

    Cinca Ionel Lupinca

    2012-09-01

    Full Text Available In the case of bimetallic sliding linings with superior technological characteristics, the use of an antifriction ally is imposed an alloy of the type Sn-Sb-Cu, which possesses a high adherence to the steel stand and a high durability in exploitation. For this reason we use the microalloying of the antifriction alloy with cadmium. The microalloying with Cd of antifriction alloys Sn-Sb-Cu determines an increase of the adhesion property of the antifriction alloy on the steel stand. The steel stand is previously subjected to a process of degreasing with ZnCl2 and washing so that is can later be subjected to a thermal-chemical treatment of tinning.

  20. Indentation creep behaviors of amorphous Cu-based composite alloys

    Science.gov (United States)

    Song, Defeng; Ma, Xiangdong; Qian, Linfang

    2018-04-01

    This work reports the indentation creep behaviors of two Si2Zr3/amorphous Cu-based composite alloys utilizing nanoindentation technique. By analysis with Kelvin model, the retardation spectra of alloys at different positions, detached and attached regions to the intermetallics, were deduced. For the indentation of detached regions to Si2Zr3 intermetallics in both alloys, very similarity in creep displacement can be observed and retardation spectra show a distinct disparity in the second retardation peak. For the indentation of detached regions, the second retardation spectra also display distinct disparity. At both positions, the retardation spectra suggest that Si elements may lead to the relatively dense structure in the amorphous matrix and to form excessive Si2Zr3 intermetallics which may deteriorate the plastic deformation of current Cu-based composite alloys.

  1. Synergistic alloying effect on microstructural evolution and mechanical properties of Cu precipitation-strengthened ferritic alloys

    International Nuclear Information System (INIS)

    Wen, Y.R.; Li, Y.P.; Hirata, A.; Zhang, Y.; Fujita, T.; Furuhara, T.; Liu, C.T.; Chiba, A.; Chen, M.W.

    2013-01-01

    We report the influence of alloying elements (Ni, Al and Mn) on the microstructural evolution of Cu-rich nanoprecipitates and the mechanical properties of Fe–Cu-based ferritic alloys. It was found that individual additions of Ni and Al do not give rise to an obvious strengthening effect, compared with the binary Fe–Cu parent alloy, although Ni segregates at the precipitate/matrix interface and Al partitions into Cu-rich precipitates. In contrast, the co-addition of Ni and Al results in the formation of core–shell nanoprecipitates with a Cu-rich core and a B2 Ni–Al shell, leading to a dramatic improvement in strength. The coarsening rate of the core–shell precipitates is about two orders of magnitude lower than that of monolithic Cu-rich precipitates in the binary and ternary Fe–Cu alloys. Reinforcement of the B2 Ni–Al shells by Mn partitioning further improves the strength of the precipitation-strengthened alloys by forming ultrastable and high number density core–shell nanoprecipitates

  2. Anodic solution of alkali earth alloys in potassium chloride-sodium chloride melts

    International Nuclear Information System (INIS)

    Volkovich, A.V.

    1997-01-01

    Generalized results of studying the process of anodic dissolution of alkaline-earth metal alloys with zinc, aluminium and copper in the melts of KCl-NaCl equimolar mixture containing alkaline-earth metal chlorides, are presented. It is shown that during dissolution of both pure liquid metals and their alloys there is no electrode polarization in the range of the current densities lower or comparable in their values to corrosion current

  3. The effect of Cu-rich sub-layer on the increased corrosion resistance of Cu-xZn alloys in chloride containing borate buffer

    International Nuclear Information System (INIS)

    Milosev, Ingrid; Mikic, Tadeja Kosec; Gaberscek, Miran

    2006-01-01

    The electrochemical behaviour of Cu-xZn alloys, as well as their constituent metals, in a borate buffer containing chloride ions in the molar range from 0.01 to 1 M are studied. Characteristics of these materials under anodic polarization are compared and the composition and morphology of the corrosion products formed in the course of polarization experiment are analysed by SEM and EDS. X-ray photoelectron spectroscopy and electrochemical impedance measurements are used for characterization of the surface layers formed on Cu, Zn and Cu-40Zn alloy during 2-h immersion at E oc in a borate buffer containing two different concentrations of chloride ions. New aspects of the behaviour of brass under E oc condition are revealed. The improved corrosion resistance of brass in chloride media, if compared to zinc metal, is attributed to a Cu-rich layer formed by the selective dissolution of zinc. Based on the results, a structural model describing the improved corrosion resistance of Cu-40Zn alloy with respect to Zn metal is proposed

  4. Wetting of molybdenum with molten Cu-O alloys

    International Nuclear Information System (INIS)

    Yupko, V.L.; Garbuz, V.V.; Kryuchkova, N.I.

    1992-01-01

    The Cu-O alloys were prepared from type MOb copper (GOST 859-78) with an oxygen content of 0.001 wt.% and type ChDA cuprous oxide (MRTU 6-09-1451-64), the powder of which was first pressed into briquettes. The weighted portions of Cu 2 O were weighed on an Elektrobalans scale having an absolute error of ±5 · 10 -7 g. The relative error in weighing an approximately 1 · 10 -4 g weighed portion of Cu 2 O for preparation of the alloy with the minimum oxygen content of 0.002% was, therefore, ± 0.5% and consequently for the alloys with a higher oxygen content the accuracy was higher. The alloys were prepared on a ZrO 2 + 5% Y 2 O 3 ceramic at 1,420 K in a vacuum of 6.7 · 10 -3 Pa,d their weight was 1.0-1.5 g, and the melting time 30 sec. The pure type MOb copper was remelted in the same manner. The time relationships of the angle of wetting of molybdenum by molten Cu-O alloys under conditions of combined heating are given. With an increase in oxygen content from 0.004 to 0.005%, wetting drops sharply

  5. Electrical resistivity of Al-Cu liquid binary alloy

    Science.gov (United States)

    Thakor, P. P.; Patel, J. J.; Sonvane, Y. A.; Jani, A. R.

    2013-06-01

    Present paper deals with the electrical resistivity (ρ) of liquid Al-Cu binary alloy. To describe electron-ion interaction we have used our parameter free model potential along with Faber-Ziman formulation combined with Ashcroft-Langreth (AL) partial structure factor. To see the influence of exchange and correlation effect, Hartree, Taylor and Sarkar et al local field correlation functions are used. From present results, it is seen that good agreements between present results and experimental data have been achieved. Lastly we conclude that our model potential successfully produces the data of electrical resistivity (ρ) of liquid Al-Cu binary alloy.

  6. Promising Cu-Ni-Cr-Si alloy for first wall ITER applications

    International Nuclear Information System (INIS)

    Ivanov, A.; Abramov, V.; Rodin, M.

    1996-01-01

    Precipitation-hardened Cu-Ni-Cr-Si alloy, a promising material for ITER applications, is considered. Available commercial products, chemical composition, physical and mechanical properties are presented. Embrittlement of Cu-Ni-Cr-Si alloy at 250-300 C is observed. Mechanical properties of Cu-Ni-Cr-Si alloy neutron irradiated to a dose of ∝0.2 dpa at 293 C are investigated. Embrittlement of Cu-Ni-Cr-Si alloy can be avoided by annealing. (orig.)

  7. Cu-segregation at the Q'/α-Al interface in Al-Mg-Si-Cu alloy

    International Nuclear Information System (INIS)

    Matsuda, Kenji; Teguri, Daisuke; Uetani, Yasuhiro; Sato, Tatsuo; Ikeno, Susumu

    2002-01-01

    Cu segregation was detected at the Q ' /α-Al interface in an Al-Mg-Si-Cu alloy by energy-filtered transmission electron microscopy. By contrast, in a Cu-free Al-Mg-Si alloy no segregation was observed at the interface between the matrix and Type-C precipitate

  8. Evaluation of lithium alloy anode materials for Li-TiS2 cells

    Science.gov (United States)

    Huang, C.-K.; Subbarao, S.; Shen, D. H.; Deligiannis, F.; Attia, A.; Halpert, G.

    1991-01-01

    A study was performed to select candidate lithium alloy anode materials and establish selection criteria. Some of the selected alloy materials were evaluated for their electrochemical properties and performance. This paper describes the criteria for the selection of alloys and the findings of the studies. Li-Si and Li-Cd alloys have been found to be unstable in the EC+2-MeTHF-based electrolyte. The Li-Al alloy system was found to be promising among the alloy systems studied in view of its stability and reversibility. Unfortunately, the large volume changes of LiAl alloys during charge/discharge cycling cause considerable 'exfoliation' of its active mass. This paper also describes ways how to address this problem. The rate of disintegration of this anode would probably be surpressed by the presence of an inert solid solution or a uniform distribution of precipitates within the grains of the active mass. It was discovered that the addition of a small quantity of Mn may improve the mechanical properties of LiAl. In an attempt to reduce the Li-Al alloy vs. Li voltage, it was observed that LiAlPb(0.1)Cd(0.3) material can be cycled at 1.5 mA/sq cm without exfoliation of the active mass.

  9. PEO of pre-anodized Al–Si alloys: Corrosion properties and influence of sealings

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, M., E-mail: marta.mohedano@hzg.de [Helmholtz Zentrum Geesthacht, Magnesium Innovation Centre, Institute of Materials Research, Max-Planck-Str. 1, D-21502 Geesthacht (Germany); Matykina, E.; Arrabal, R.; Mingo, B.; Pardo, A. [Departamento de Ciencia de Materiales, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid (Spain)

    2015-08-15

    Highlights: • A356 gravity-cast and rheocast pre-anodized aluminium alloys were coated by PEO. • Different sealing techniques were applied after the coating process. • Iron-rich constituents of the substrate occlude the continuity of the porous anodic film. • PEO coatings consisted of a mixture of α-Al{sub 2}O{sub 3}, γ-Al{sub 2}O{sub 3} and mullite. • Post-treatments improved both hydrophobic and corrosion properties. - Abstract: Voltage-controlled PEO coatings were developed on A356 aluminum alloys (gravity-cast and rheocast) with a pre-anodized layer. The influence of the alloy manufacturing process and the effect of Si-rich phase on the structure and composition of the oxide layers were evaluated using SEM, EDS and XRD. The pre-anodized oxide layer preserves the microstructure of the substrate due to the presence of secondary phases that have a different behavior relative to the matrix during anodizing. PEO coatings consisted of a mixture of α-Al{sub 2}O{sub 3}, γ-Al{sub 2}O{sub 3} and mullite. The corrosion behavior and the effectiveness of different sealing techniques based on salts of nickel, cobalt, cerium and phosphonic acid were also studied. Post-treatments improved the hydrophobic properties of the coatings and showed a beneficial effect, significantly increasing the coating impedance and thereby reducing the susceptibility to corrosion.

  10. Effect of alloying elements on the shape memory properties of ductile Cu-Al-Mn alloys

    International Nuclear Information System (INIS)

    Sutou, Y.; Kainuma, R.; Ishida, K.

    1999-01-01

    The effect of alloying elements on the M s temperature, ductility and the shape memory properties of Cu-Al-Mn ductile shape memory (SM) alloys was investigated by differential scanning calorimetry, cold-rolling and tensile test techniques. It was found that the addition of Au, Si and Zn to the Cu 73 -Al 17 -Mn 10 alloy stabilized the martensite (6M) phase increasing the M s temperature, while the addition of Ag, Co, Cr, Fe, Ni, Sn and Ti decreased the stability of the martensite phase, decreasing the M s temperature. The SM properties were improved by the addition of Co, Ni, Cr and Ti. (orig.)

  11. The Effect of Grain Size on Mechanical Instability in Single-Phase Li-Alloy Anodes

    National Research Council Canada - National Science Library

    Wolfenstine, Jeff

    2000-01-01

    .... The results of this study suggest that decreasing the particle and/or grain size is not a practical approach to solving the mechanical instability problem of single phase Li alloys that are intended to be used as anodes in Li-ion batteries.

  12. Remediation of phosphate-contaminated water by electrocoagulation with aluminium, aluminium alloy and mild steel anodes.

    Science.gov (United States)

    Vasudevan, Subramanyan; Lakshmi, Jothinathan; Jayaraj, Jeganathan; Sozhan, Ganapathy

    2009-05-30

    The present study provides an electrocoagulation process for the remediation of phosphate-contaminated water using aluminium, aluminium alloy and mild steel as the anodes and stainless steel as the cathode. The various parameters like effect of anode materials, effect of pH, concentration of phosphate, current density, temperature and co-existing ions, and so forth, and the adsorption capacity was evaluated using both Freundlich and Langmuir isotherm models. The adsorption of phosphate preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The results showed that the maximum removal efficiency of 99% was achieved with aluminium alloy anode at a current density of 0.2 A dm(-2), at a pH of 7.0. The adsorption process follows second-order kinetics.

  13. PEO of pre-anodized Al-Si alloys: Corrosion properties and influence of sealings

    Science.gov (United States)

    Mohedano, M.; Matykina, E.; Arrabal, R.; Mingo, B.; Pardo, A.

    2015-08-01

    Voltage-controlled PEO coatings were developed on A356 aluminum alloys (gravity-cast and rheocast) with a pre-anodized layer. The influence of the alloy manufacturing process and the effect of Si-rich phase on the structure and composition of the oxide layers were evaluated using SEM, EDS and XRD. The pre-anodized oxide layer preserves the microstructure of the substrate due to the presence of secondary phases that have a different behavior relative to the matrix during anodizing. PEO coatings consisted of a mixture of α-Al2O3, γ-Al2O3 and mullite. The corrosion behavior and the effectiveness of different sealing techniques based on salts of nickel, cobalt, cerium and phosphonic acid were also studied. Post-treatments improved the hydrophobic properties of the coatings and showed a beneficial effect, significantly increasing the coating impedance and thereby reducing the susceptibility to corrosion.

  14. Stability of rapidly quenched and hydrogenated Mg-Ni-Y and Mg-Cu-Y alloys in extreme alkaline medium

    International Nuclear Information System (INIS)

    Gebert, A.; Khorkounov, B.; Wolff, U.; Mickel, Ch.; Uhlemann, M.; Schultz, L.

    2006-01-01

    Amorphous-nanocrystalline Mg 50 Ni 30 Y 20 and Mg 63 Ni 30 Y 7 and amorphous Mg 65 Cu 25 Y 10 alloys were produced by melt-spinning and characterized regarding their microstructure and thermal behaviour using XRD, TEM and DSC. Their electrochemical behaviour in the as-quenched state and after hydrogen charging at -25 mA/cm 2 for up to 20 h was studied in electrolytes with pH 5-7 and 13, but mainly in a battery electrolyte: 6 M KOH with pH 14.8 by means of anodic and cathodic polarization measurements. In the as-quenched state, the highest alloys stability was observed at pH 13. At pH 14.8, gradual oxidation and dissolution of copper or nickel governs the anodic behaviour before a passive state is attained. The dissolution of nickel is much more inhibited than that of copper due to its lower tendency to form soluble oxidized ions and to a stabilizing effect of higher fractions of yttrium in the alloy on the passivation. By galvanostatic charging, the Mg 65 Cu 25 Y 10 alloy shows the highest hydrogen absorption capacity followed by Mg 50 Ni 30 Y 20 and Mg 63 Ni 30 Y 7 . During the charging process, the alloys exhibit a change in the surface state chemistry, i.e. an enrichment of nickel- or copper-rich species, causing preferential oxidation and dissolution during subsequent exposure under free corrosion and anodic conditions. Mg-Ni-Y alloys demonstrate a higher stability during this treatment in extreme alkaline medium. The reasons for this and consequences regarding the use as electrode materials are discussed in detail

  15. Elemental separation in nanocrystalline Cu-Al alloys

    Science.gov (United States)

    Wang, Y. B.; Liao, X. Z.; Zhao, Y. H.; Cooley, J. C.; Horita, Z.; Zhu, Y. T.

    2013-06-01

    Nanocrystallization by high-energy severe plastic deformation has been reported to increase the solubility of alloy systems and even to mix immiscible elements to form non-equilibrium solid solutions. In this letter, we report an opposite phenomenon—nanocrystallization of a Cu-Al single-phase solid solution by high-pressure torsion separated Al from the Cu matrix when the grain sizes are refined to tens of nanometers. The Al phase was found to form at the grain boundaries of nanocrystalline Cu. The level of the separation increases with decreasing grain size, which suggests that the elemental separation was caused by the grain size effect.

  16. Mercury embrittlement of Cu-Al alloys under cyclic loading

    Science.gov (United States)

    Regan, T. M.; Stoloff, N. S.

    1977-01-01

    The effect of mercury on the room temperature, high cycle fatigue properties of three alloys: Cu-5.5 pct Al, Cu-7.3 pct Al, and Cu-6.3 pct Al-2.5 pct Fe has been determined. Severe embrittlement under cyclic loading in mercury is associated with rapid crack propagation in the presence of the liquid metal. A pronounced grain size effect is noted under mercury, while fatigue properties in air are insensitive to grain size. The fatigue results are discussed in relation to theories of adsorption-induced liquid metal embrittlement.

  17. Fabrication of the micro/nano-structure superhydrophobic surface on aluminum alloy by sulfuric acid anodizing and polypropylene coating.

    Science.gov (United States)

    Wu, Ruomei; Liang, Shuquan; Liu, Jun; Pan, Anqiang; Yu, Y; Tang, Yan

    2013-03-01

    The preparation of the superhydrophobic surface on aluminum alloy by anodizing and polypropylene (PP) coating was reported. Both the different anodizing process and different PP coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. By PP coating after anodizing, a good superhydrophobic surface was facilely fabricated. The optimum conditions for anodizing were determined by orthogonal experiments. After the aluminium-alloy was grinded with 600# sandpaper, pretreated by 73 g/L hydrochloric acid solution at 1 min, when the concentration of sulfuric acid was 180 g/L, the concentration of oxalic acid was 5 g/L, the concentration of potassium dichromate was 10 g/L, the concentration of chloride sodium was 50 g/L and 63 g/L of glycerol, anodization time was 20 min, and anodization current was 1.2 A/dm2, anodization temperature was 30-35 degrees C, the best micro-nanostructure aluminum alloy films was obtained. On the other hand, the PP with different concentrations was used to the PP with different concentrations was used to coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was achieved by coating PP, and the duration of the superhydrophobic surface was improved by modifying the coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was surface with high concentration PP. The morphologies of micro/nano-structure superhydrophobic surface were further confirmed by scanning electron microscope (SEM). The material of PP with the low surface free energy combined with the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  18. Potentiodynamic polarization studies of bulk amorphous alloy Zr57Cu15.4Ni12.6Al10Nb5 and Zr59Cu20Ni8Al10Ti3 in aqueous HNO3 media

    International Nuclear Information System (INIS)

    Sharma, Poonam; Dhawan, Anil; Jayraj, J.; Kamachi Mudali, U.

    2013-01-01

    The potentiodynamic polarization studies were carried out on Zr based bulk amorphous alloy Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 and Zr 59 Cu 20 Ni 8 Al 10 Ti 3 in solutions of 1 M, 6 M and 11.5 M HNO 3 aqueous media at room temperature. As received specimens of Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 (5 mm diameter rod) and Zr 59 Cu 20 Ni 8 Al 10 Ti 3 (3 mm diameter rod) were polished with SiC paper before testing them for potentiodynamic polarization studies. The amorphous nature of the specimens was checked by X-ray diffraction. The bulk amorphous alloy Zr 59 Cu 20 Ni 8 Al 10 Ti 3 shows the better corrosion resistance than Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 alloy in the aqueous HNO 3 media as the value of the corrosion current density (I corr ) for Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 alloy were found to be more than Zr 59 Cu 20 Ni 8 Al 10 Ti 3 alloy in aqueous HNO 3 media. The improved corrosion resistance of Zr 59 Cu 20 Ni 8 Al 10 Ti 3 alloy is possibly due to the presence of Ti and formation of TiO 2 during anodic oxidation. Both Zr based bulk amorphous alloys shows wider passive range at lower concentration of nitric acid and the passive region gets narrowed down with the increase in concentration. A comparison of data obtained from both the Zr-based bulk amorphous alloys is made and results are discussed in the paper. (author)

  19. Phase stability of CuAlMn shape memory alloys

    Czech Academy of Sciences Publication Activity Database

    Zárubová, Niva; Novák, Václav

    2004-01-01

    Roč. 378, - (2004), s. 216-221 ISSN 0921-5093 Institutional research plan: CEZ:AV0Z1010914 Keywords : CuAlMn * shape memory alloys * martensitic transformation * - stress -strain tests * tension-compression cycling * history dependent phenomena Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.445, year: 2004

  20. 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...

  1. CuZn Alloy- Based Electrocatalyst for CO2 Reduction

    KAUST Repository

    Alazmi, Amira

    2014-01-01

    , especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys

  2. Local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys investigated by EXAFS method

    International Nuclear Information System (INIS)

    Antonowicz, J.; Pietnoczka, A.; Zalewski, W.; Bacewicz, R.; Stoica, M.; Georgarakis, K.; Yavari, A.R.

    2011-01-01

    Research highlights: → Coordination number, interatomic distances and mean square atomic displacement in Zr-Cu and Zr-Cu-Al glasses. → Icosahedral symmetry in local atomic structure. → Deviation from random mixing behavior resulting from Al addition. - Abstract: We report on extended X-ray absorption fine structure (EXAFS) study of rapidly quenched Zr-Cu and Zr-Cu-Al glassy alloys. The local atomic order around Zr and Cu atoms was investigated. From the EXAFS data fitting the values of coordination number, interatomic distances and mean square atomic displacement were obtained for wide range of compositions. It was found that icosahedral symmetry rather than that of corresponding crystalline analogs dominates in the local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys. Judging from bonding preferences we conclude that addition of Al as an alloying element results in considerable deviation from random mixing behavior observed in binary Zr-Cu alloys.

  3. Glass-formation and hardness of Cu-Y alloys

    Energy Technology Data Exchange (ETDEWEB)

    Satta, Marta; Rizzi, Paola [Dipartimento di Chimica IFM and NIS/INSTM/CNISM, Universita di Torino, v. Giuria 9, I-10125 Torino (Italy); Baricco, Marcello, E-mail: marcello.baricco@unito.i [Dipartimento di Chimica IFM and NIS/INSTM/CNISM, Universita di Torino, v. Giuria 9, I-10125 Torino (Italy)

    2009-08-26

    Metallic glasses exhibit particularly attractive mechanical properties, like high stresses to fracture and large elastic strain (up to 2%), but they show generally low plasticity. Aim of this work is to investigate the glass forming range in the Cu-Y system, in order to form the ductile CuY phase (CsCl structure) upon crystallization. Cu{sub 58}Y{sub 42}, Cu{sub 50}Y{sub 50} and Cu{sub 33}Y{sub 67} alloys have been prepared by rapid solidification and copper mould casting, obtaining ribbons and cylindrical shaped ingots, with diameter of 2 mm. Fully amorphous, partially amorphous and fully crystalline samples have been obtained for different compositions and quenching conditions. In some cases, the X-ray diffraction results, analysed using the Rietveld method, showed CuY nanocrystals embedded in an amorphous matrix. The microstructure was studied by transmission electron microscopy (TEM) and the presence of nanocrystals of the ductile phase CuY has been confirmed. Microhardness results showed a softening of the amorphous phase due to the presence of CuY nanocrystals and a hardening due to the Cu{sub 2}Y phase.

  4. Glass-formation and hardness of Cu-Y alloys

    International Nuclear Information System (INIS)

    Satta, Marta; Rizzi, Paola; Baricco, Marcello

    2009-01-01

    Metallic glasses exhibit particularly attractive mechanical properties, like high stresses to fracture and large elastic strain (up to 2%), but they show generally low plasticity. Aim of this work is to investigate the glass forming range in the Cu-Y system, in order to form the ductile CuY phase (CsCl structure) upon crystallization. Cu 58 Y 42 , Cu 50 Y 50 and Cu 33 Y 67 alloys have been prepared by rapid solidification and copper mould casting, obtaining ribbons and cylindrical shaped ingots, with diameter of 2 mm. Fully amorphous, partially amorphous and fully crystalline samples have been obtained for different compositions and quenching conditions. In some cases, the X-ray diffraction results, analysed using the Rietveld method, showed CuY nanocrystals embedded in an amorphous matrix. The microstructure was studied by transmission electron microscopy (TEM) and the presence of nanocrystals of the ductile phase CuY has been confirmed. Microhardness results showed a softening of the amorphous phase due to the presence of CuY nanocrystals and a hardening due to the Cu 2 Y phase.

  5. Compositionally graded SiCu thin film anode by magnetron sputtering for lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Polat, B.D., E-mail: bpolat@itu.edu.tr [Department of Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, Istanbul 34469 (Turkey); Eryilmaz, O.L. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Keleş, O., E-mail: ozgulkeles@itu.edu.tr [Department of Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, Istanbul 34469 (Turkey); Erdemir, A. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Amine, K. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-12-01

    Compositionally graded and non-graded composite SiCu thin films were deposited by magnetron sputtering technique on Cu disks for investigation of their potentials in lithium ion battery applications. The compositionally graded thin film electrodes with 30 at.% Cu delivered a 1400 mAh g{sup −1} capacity with 80% Coulombic efficiency in the first cycle and still retained its capacity at around 600 mAh g{sup −1} (with 99.9% Coulombic efficiency) even after 100 cycles. On the other hand, the non-graded thin film electrodes with 30 at.% Cu exhibited 1100 mAh g{sup −1} as the first discharge capacity with 78% Coulombic efficiency but the cycle life of this film degraded very quickly, delivering only 250 mAh g{sup −1} capacity after 100th cycles. Not only the Cu content but also the graded film thickness were believed to be the main contributors to the much superior performance of the compositionally graded SiCu films. We also believe that the Cu-rich region of the graded film helped reduce internal stress build-up and thus prevented film delamination during cycling. In particular, the decrease of Cu content from interface region to the top of the coating reduced the possibility of stress build-up across the film during cycling, thus leading to a high electrochemical performance.b - Highlights: • Highly adherent SiCu films are deposited by magnetron sputtering. • Compositionally graded SiCu film is produced and characterized. • Decrease of Cu content diverted the propagation of stress in the anode. • Cu rich layer at the bottom improves the adherence of the film.

  6. Corrosion of Cu-xZn alloys in slightly alkaline chloride solutions studied by stripping voltammetry and microanalysis.

    Science.gov (United States)

    Milosev, I; Minović, A

    2001-01-01

    The mechanism of corrosion of Cu-xZn alloys (x = 10-40 wt %) in slightly alkaline chloride solutions was investigated by analysing solid reaction products by energy dispersive X-ray analysis (EDS) and dissolved reaction products by differential anodic pulse stripping (DAPS) voltammetry. The corrosion process was studied under open circuit and under potentiostatic conditions at selected potentials. Pure metals were studied comparatively so that an interacting effect of particular metal components in the alloy could be determined. All four Cu-xZn alloys show an improved behaviour compared to pure metals. Under open-circuit condition both components dissolve simultaneously in the solution. With increasing immersion time the preferential, dissolution of zinc in the solution becomes pronounced. It is the highest for Cu-10Zn and the lowest for Cu-30Zn alloy. Under potentiostatic control the dissolution mechanism depends on the electrode potential and changes from exclusive dissolution of zinc to simultaneous dissolution of both components with preferential dissolution of zinc. The latter decreases, as the electrode potential becomes more positive.

  7. Ceramic carbon electrode-based anodes for use in the Cu-Cl thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, Santhanam; Easton, E. Bradley [Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada)

    2010-05-15

    We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. CCE-based electrodes vastly outperform a bare carbon electrode. Optimization of the organosilicate loading revealed maximum electrode performance was achieved with 36 wt% and was explained in terms of the optimal balance of active area and anion transport properties. (author)

  8. 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.).

  9. Enhanced corrosion resistance and biocompatibility of β-type Ti–25Nb–25Zr alloy by electrochemical anodization

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei, 112 Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, 404 Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung, 413 Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei, 112 Taiwan (China); Wu, Chia-Ping; Sun, Ying-Sui; Huang, Hsun-Miao [Institute of Oral Biology, National Yang-Ming University, Taipei, 112 Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung, 402 Taiwan (China); Oral Medicine Center, Chung Shan Medical University Hospital, Taichung, 402 Taiwan (China)

    2013-12-31

    The biocompatibility of implants is largely determined by their surface characteristics. This study presents a novel method for performing electrochemical anodization on β-type Ti–25Nb–25Zr alloy with a low elastic modulus (approximately 70 GPa). This method results in a thin hybrid layer capable of enhancing the surface characteristics of the implants. We investigated the surface topography and microstructure of the resulting Ti–25Nb–25Zr alloy. The corrosion resistance was evaluated using potentiodynamic polarization curve measurements in simulated body fluid. The cytotoxicity was evaluated according to International Organization for Standardization 10993–5 specification. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed using scanning electron microscopy and fluorescence microscopy. The anodization produced a thin (approximately 40 nm-thick) hybrid oxide layer with a nanoporous outer sublayer (pore size < 15 nm) and a dense inner layer. The thin hybrid oxide layer increased the corrosion resistance of the Ti–25Nb–25Zr alloy by increasing the corrosion potential and decreasing both the corrosion rate and passive current. Ti–25Nb–25Zr alloys with and without anodization treatment were non-toxic. Surface nanotopography on the anodized Ti–25Nb–25Zr alloy enhanced protein adsorption and cell adhesion. Our results demonstrate that electrochemical anodization increases the corrosion resistance and cell adhesion of β-type Ti–25Nb–25Zr alloy while providing a lower elastic modulus suitable for implant applications. - Highlights: • An electrochemical anodization was applied to β-type Ti–25Nb–25Zr alloy surface. • Anodized surface had nanoscale hybrid oxide layer. • Anodized surface increased corrosion resistance due to dense inner sublayer. • Anodized surface enhanced cell adhesion due to nanoporous outer sublayer. • Electrochemical anodization has potential as implant surface treatment.

  10. Enhanced corrosion resistance and biocompatibility of β-type Ti–25Nb–25Zr alloy by electrochemical anodization

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Huang, Hsun-Miao; Lee, Tzu-Hsin

    2013-01-01

    The biocompatibility of implants is largely determined by their surface characteristics. This study presents a novel method for performing electrochemical anodization on β-type Ti–25Nb–25Zr alloy with a low elastic modulus (approximately 70 GPa). This method results in a thin hybrid layer capable of enhancing the surface characteristics of the implants. We investigated the surface topography and microstructure of the resulting Ti–25Nb–25Zr alloy. The corrosion resistance was evaluated using potentiodynamic polarization curve measurements in simulated body fluid. The cytotoxicity was evaluated according to International Organization for Standardization 10993–5 specification. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed using scanning electron microscopy and fluorescence microscopy. The anodization produced a thin (approximately 40 nm-thick) hybrid oxide layer with a nanoporous outer sublayer (pore size < 15 nm) and a dense inner layer. The thin hybrid oxide layer increased the corrosion resistance of the Ti–25Nb–25Zr alloy by increasing the corrosion potential and decreasing both the corrosion rate and passive current. Ti–25Nb–25Zr alloys with and without anodization treatment were non-toxic. Surface nanotopography on the anodized Ti–25Nb–25Zr alloy enhanced protein adsorption and cell adhesion. Our results demonstrate that electrochemical anodization increases the corrosion resistance and cell adhesion of β-type Ti–25Nb–25Zr alloy while providing a lower elastic modulus suitable for implant applications. - Highlights: • An electrochemical anodization was applied to β-type Ti–25Nb–25Zr alloy surface. • Anodized surface had nanoscale hybrid oxide layer. • Anodized surface increased corrosion resistance due to dense inner sublayer. • Anodized surface enhanced cell adhesion due to nanoporous outer sublayer. • Electrochemical anodization has potential as implant surface treatment

  11. Improvements in the corrosion resistance and biocompatibility of biomedical Ti–6Al–7Nb alloy using an electrochemical anodization treatment

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Department of Dentistry, Taipei City Hospital, Taipei 115, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China); Wu, Chia-Ping; Sun, Ying-Sui [Department of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2013-01-01

    The biocompatibility of an implant material is determined by its surface characteristics. This study investigated the application of an electrochemical anodization surface treatment to improve both the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for implant applications. The electrochemical anodization treatment produced an Al-free oxide layer with nanoscale porosity on the Ti–6Al–7Nb alloy surface. The surface topography and microstructure of Ti–6Al–7Nb alloy were analyzed. The corrosion resistance was investigated using potentiodynamic polarization curve measurements in simulated blood plasma (SBP). The adhesion and proliferation of human bone marrow mesenchymal stem cells to test specimens were evaluated using various biological analysis techniques. The results showed that the presence of a nanoporous oxide layer on the anodized Ti–6Al–7Nb alloy increased the corrosion resistance (i.e., increased the corrosion potential and decreased both the corrosion rate and the passive current) in SBP compared with the untreated Ti–6Al–7Nb alloy. Changes in the nanotopography also improved the cell adhesion and proliferation on the anodized Ti–6Al–7Nb alloy. We conclude that a fast and simple electrochemical anodization surface treatment improves the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for biomedical implant applications. - Highlights: ► Simple/fast electrochemical anodization was applied to biomedical Ti–6Al–7Nb surface. ► Anodized surface had nano-porous topography and contained Al-free oxide layer. ► Anodized surface raised corrosion resistance in three simulated biological solutions. ► Anodized surface enhanced cell adhesion and cell proliferation. ► Electrochemical anodization has potential as biomedical implant surface treatment.

  12. Improvements in the corrosion resistance and biocompatibility of biomedical Ti–6Al–7Nb alloy using an electrochemical anodization treatment

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Lee, Tzu-Hsin

    2013-01-01

    The biocompatibility of an implant material is determined by its surface characteristics. This study investigated the application of an electrochemical anodization surface treatment to improve both the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for implant applications. The electrochemical anodization treatment produced an Al-free oxide layer with nanoscale porosity on the Ti–6Al–7Nb alloy surface. The surface topography and microstructure of Ti–6Al–7Nb alloy were analyzed. The corrosion resistance was investigated using potentiodynamic polarization curve measurements in simulated blood plasma (SBP). The adhesion and proliferation of human bone marrow mesenchymal stem cells to test specimens were evaluated using various biological analysis techniques. The results showed that the presence of a nanoporous oxide layer on the anodized Ti–6Al–7Nb alloy increased the corrosion resistance (i.e., increased the corrosion potential and decreased both the corrosion rate and the passive current) in SBP compared with the untreated Ti–6Al–7Nb alloy. Changes in the nanotopography also improved the cell adhesion and proliferation on the anodized Ti–6Al–7Nb alloy. We conclude that a fast and simple electrochemical anodization surface treatment improves the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for biomedical implant applications. - Highlights: ► Simple/fast electrochemical anodization was applied to biomedical Ti–6Al–7Nb surface. ► Anodized surface had nano-porous topography and contained Al-free oxide layer. ► Anodized surface raised corrosion resistance in three simulated biological solutions. ► Anodized surface enhanced cell adhesion and cell proliferation. ► Electrochemical anodization has potential as biomedical implant surface treatment

  13. Multishelled Si@Cu Microparticles Supported on 3D Cu Current Collectors for Stable and Binder-free Anodes of Lithium-Ion Batteries.

    Science.gov (United States)

    Zhang, Zailei; Wang, Zhong Lin; Lu, Xianmao

    2018-04-24

    Silicon has proved to be a promising anode material of high-specific capacity for the next-generation lithium ion batteries (LIBs). However, during repeated discharge/charge cycles, Si-based electrodes, especially those in microscale size, pulverize and lose electrical contact with the current collectors due to large volume expansion. Here, we introduce a general method to synthesize Cu@M (M = Si, Al, C, SiO 2 , Si 3 N 4 , Ag, Ti, Ta, SnIn 2 O 5 , Au, V, Nb, W, Mg, Fe, Ni, Sn, ZnO, TiN, Al 2 O 3 , HfO 2 , and TiO 2 ) core-shell nanowire arrays on Cu substrates. The resulting Cu@Si nanowire arrays were employed as LIB anodes that can be reused via HCl etching and H 2 -reduction. Multishelled Cu@Si@Cu microparticles supported on 3D Cu current collectors were further prepared as stable and binder-free LIB anodes. This 3D Cu@Si@Cu structure allows the interior conductive Cu network to effectively accommodate the volume expansion of the electrode and facilitates the contact between the Cu@Si@Cu particles and the current collectors during the repeated insertion/extraction of lithium ions. As a result, the 3D Cu@Si@Cu microparticles at a high Si-loading of 1.08 mg/cm 2 showed a capacity retention of 81% after 200 cycles. In addition, charging tests of 3D Cu@Si@Cu-LiFePO 4 full cells by a triboelectric nanogenerator with a pulsed current demonstrated that LIBs with silicon anodes can effectively store energy delivered by mechanical energy harvesters.

  14. Influence of Alkali Treatment on Anodized Titanium Alloys in Wollastonite Suspension

    Directory of Open Access Journals (Sweden)

    Alicja Kazek-Kęsik

    2017-08-01

    Full Text Available The surface modification of titanium alloys is an effective method to improve their biocompatibility and tailor the material to the desired profile of implant functionality. In this work, technologically-advanced titanium alloys—Ti-15Mo, Ti-13Nb-13Zr and Ti-6Al-7Nb—were anodized in suspensions, followed by treatment in alkali solutions, with wollastonite deposition from the powder phase suspended in solution. The anodized samples were immersed in NaOH or KOH solution with various concentrations with a different set of temperatures and exposure times. Based on their morphologies (observed by scanning electron microscope, the selected samples were investigated by Raman and X-ray photoelectron spectroscopy (XPS. Titaniate compounds were formed on the previously anodized titanium surfaces. The surface wettability significantly decreased, mainly on the modified Ti-15Mo alloy surface. Titanium alloy compounds had an influence on the results of the titanium alloys’ surface modification, which caused the surfaces to exhibit differential physical properties. In this paper, we present the influence of the anodization procedure on alkali treatment effects and the properties of obtained hybrid coatings.

  15. Effect of temperature on the anodizing process of aluminum alloy AA 5052

    Science.gov (United States)

    Theohari, S.; Kontogeorgou, Ch.

    2013-11-01

    The effect of temperature (10-40 °C) during the anodizing process of AA 5052 for 40 min in 175 g/L sulfuric acid solution at constant voltage (15 V) was studied in comparison with pure aluminum. The incorporated magnesium species in the barrier layer result in the further increase of the minimum current density passed during anodizing, as the temperature increases, by about 42% up to 30 °C and then by 12% up to 40 °C. Then during the anodizing process for 40 min a blocking effect on oxide film growth was gradually observed as the temperature increased until 30 °C. The results of EDAX analysis on thick films reveal that the mean amount of the magnesium species inside the film is about 50-70% less than that in the bulk alloy, while it is higher at certain locations adjacent to the film surface at 30 °C. The increase of anodizing temperature does not influence the porosity of thin films (formed for short times) on pure aluminum, while it reduces it on the alloy. At 40 °C the above mentioned blocking effects disappear. It means that the presence of magnesium species causes an impediment to the effect of temperature on iss, on the film thickness and on the porosity of thin films, only under conditions where film growth takes place without significant loss of the anodizing charge to side reactions.

  16. Kinematic viscosity of liquid Al-Cu alloys

    International Nuclear Information System (INIS)

    Konstantinova, N Yu; Popel, P S

    2008-01-01

    Temperature dependences of kinematic viscosity n of liquid Al 100-x -Cu x alloys (x = 0.0, 10.0, 17.1, 25.0, 32.2, 40.0 and 50.0 at.%) were measured. A technique based on registration of the period and the decrement of damping of rotating oscillations of a cylindrical crucible with a melt was used. Viscosity was calculated in low viscous liquids approximation. Measurements were carried out in vacuum in crucibles of BeO with a temperature step of 30 deg. C and isothermal expositions of 10 to 15 minutes during both heating up to 1100-1250 deg. C and subsequent cooling. We have discovered branching of heating and cooling curves v(T) (hysteresis of viscosity) below temperatures depending on the copper content: 950 deg. C at 10 and 17.1 at.% Cu, 1050 deg. C at 25 and 40 at.% Cu, 850 deg. C at 32.2 at.% Cu. For samples with 10 and 17.1 at.% Cu the cooling curve 'returns' to the heating one near 700 deg. C. An abnormally high spreading of results at repeated decrement measurements was fixed at heating of the alloy containing 50 at.% Cu above 1000 deg. C. During subsequent cooling the effect disappeared. Isotherms of kinematic viscosity have been fitted for several temperatures

  17. 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.

  18. Investigation of new type Cu-Hf-Al bulk glassy alloys

    International Nuclear Information System (INIS)

    Nagy, E; Ronto, V; Solyom, J; Roosz, A

    2009-01-01

    In the last years new type Cu-Hf-Al ternary alloys were developed with high glass forming ability and ductility. The addition of Al to Cu-Hf alloys results in improvements in glass formation, thermal stability and mechanical properties of these alloys. We have investigated new Cu-based bulk amorphous alloys in Cu-Hf-Al ternary system. The alloys with Cu 49 Hf 42 Al 9 , Cu 46 Hf 45 Al 9 , Cu 50 Hf 42.5 Al 7.5 and Cu 50 Hf 45 Al 5 compositions were prepared by arc melting. The samples were made by centrifugal casting and were investigated by X-ray diffraction method. Thermodynamic properties were examined by differential scanning calorimetry and the structure of the crystallising phases by scanning electron microscopy. The determination of liquidus temperatures of alloys were measured by differential thermal analysis.

  19. Influence of electroless coatings of Cu, Ni-P and Co-P on MmNi3.25Al0.35Mn0.25Co0.66 alloy used as anodes in Ni-MH batteries

    International Nuclear Information System (INIS)

    Raju, M.; Ananth, M.V.; Vijayaraghavan, L.

    2009-01-01

    Electroless coatings of Ni-P, Co-P and Cu were applied on the surface of non-stoichiometric MmNi 3.25 Al 0.35 Mn 0.25 Co 0.66 (Mm: misch metal) metal hydride alloy. Elemental analysis was made with Energy Dispersive X-ray Analysis (EDAX). The structural analysis of bare and coated alloys was done by X-ray diffraction (XRD) whereas surface morphology was examined with scanning electron microscope (SEM) and transmission electron microscope (TEM). The electrode characteristics inclusive of electrochemical capacity and cycle life were studied at C/5 rate. Superior performance is obtained with copper coated alloy. Microstructure observations indicate that the observed excellent performance could be attributed to uniform and efficient surface coverage with copper. Also, lanthanum surface enrichment in samples during Cu coating leads to improvement in performance. It is inferred from electro analytical investigations that copper coatings act as microcurrent collectors with alterations in hydrogen transport mechanism and facilitate charge transfer reaction on the alloy surface without altering battery properties. Moreover, supportive first time TEM evidence of existence of such copper nano current collectors (about 8 nm in diameter and length about 20 nm) is reported.

  20. 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)

  1. The effect of zinc on the microstructure and phase transformations of casting Al-Cu alloys

    OpenAIRE

    Manasijević Ivana I.; Štrbac Nada D.; Živković Dragana T.; Balanović Ljubiša T.; Minić Duško M.; Manasijević Dragan M.

    2016-01-01

    Copper is one of the main alloying elements for aluminum casting alloys. As an alloying element, copper significantly increases the tensile strength and toughness of alloys based on aluminum. The copper content in the industrial casting aluminum alloys ranges from 3,5 to 11 wt.%. However, despite the positive effect on the mechanical properties, copper has a negative influence on the corrosion resistance of aluminum and its alloys. In order to further improve the properties of Al-Cu alloys th...

  2. CuZn Alloy- Based Electrocatalyst for CO2 Reduction

    KAUST Repository

    Alazmi, Amira

    2014-06-01

    ABSTRACT CuZn Alloy- Based Electrocatalyst for CO2 Reduction Amira Alazmi Carbon dioxide (CO2) is one of the major greenhouse gases and its emission is a significant threat to global economy and sustainability. Efficient CO2 conversion leads to utilization of CO2 as a carbon feedstock, but activating the most stable carbon-based molecule, CO2, is a challenging task. Electrochemical conversion of CO2 is considered to be the beneficial approach to generate carbon-containing fuels directly from CO2, especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys with heat treatments at different temperatures have been evaluated as electrocatalysts for CO2 reduction. It was found that the catalytic activity of these electrodes was strongly dependent on the thermal oxidation temperature before their use for electrochemical measurements. The polycrystalline CuZn electrode without thermal treatment shows the Faradaic efficiency for CO formation of only 30% at applied potential ~−1.0 V vs. RHE with current density of ~−2.55 mA cm−2. In contrast, the reduction of oxide-based CuZn alloy electrode exhibits 65% Faradaic efficiency for CO at lower applied potential about −1.0 V vs. RHE with current density of −2.55 mA cm−2. Furthermore, stable activity was achieved over several hours of the reduction reaction at the modified electrodes. Based on electrokinetic studies, this improvement could be attributed to further stabilization of the CO2•− on the oxide-based Cu-Zn alloy surface.

  3. Virtual thermal expansion coefficient of Cu precipitated in the Fe95Cu5 alloy

    International Nuclear Information System (INIS)

    Koeszegi, L.; Somogyvari, Z.

    1999-01-01

    Complete text of publication follows. Precipitations on grain boundaries play very important role in the formation of material's characteristics like embrittlement, durability etc. It was already shown [1] that Cu precipitations are under different stress conditions than the bulk material. The situation is more complicated in the case when a construction is exposed to temperature changes as well. In that case not only the residual stresses during the fabrication but the different thermal expansion coefficients can produce additional problems. This situation was modelled using Fe 95 Cu 5 alloy where Cu precipitates on the grain boundaries. The alloy was produced by high-frequency melting and an extra heat treatment was used to produce a quasi-equilibrium state. Pure Cu was also measured to compare the behaviours. Cu(111) Bragg peak was measured at different temperatures by high resolution neutron diffraction. The measurements were carried out on the G5-2 spectrometer at LLB in Saclay. Measurements show that not only residual stress can be recognised on the Cu precipitates but the thermal expansion coefficient of these precipitates definitly differ from the ones of pure Cu. (author)

  4. Study of Cu-Al-Zn alloys hardness temperature dependence

    International Nuclear Information System (INIS)

    Kurmanova, D.T.; Skakov, M.K.; Melikhov, V.D.

    2001-01-01

    In the paper the results of studies for the Cu-Al-Zn ternary alloys hardness temperature dependence are presented. The method of 'hot hardness' has been used during study of the solid state phase transformations and under determination of the hot stability boundaries. Due to the samples brittleness a hardness temperature dependence definition is possible only from 350-400 deg. C. Sensitivity of the 'hot hardness' method is decreasing within high plasticity range, so the measurements have been carried out only up to 700-800 deg. C. It is shown, that the alloys hardness dependence character from temperature is close to exponential one within the certain structure modification existence domain

  5. Process of film formation by anodizing AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qian Jiangang; Li Di; Zhang Feng [School of Materials Science and Engineering, Beijing Univ. of Aeronautics and Astronautics (China)

    2005-07-01

    The kinetics of film-forming process by anodizing AZ91D Mg alloy has been studied by ways of voltage-time and thickness-time curve, and the surface morphology, structure, composition and valence of element, phase constituent of anodic films have been analyzed by SEM, EDS, XPS and XRD respectively. The results show that the film-forming course can be divided into four stages. Formation of dense layer before sparking is the first stage. Formation of porous layer accompanied with a bit of small sparking is the second stage. Porous layer fast growth along with middle sparking is the third stage. Porous layer slowly-growth along with bigger sparking is the fourth stage. The anodic films contains approximately Mg,O,Si and B, which is composed mainly of MgO, MgSiO{sub 3} and Mg{sub 3}B{sub 2}O{sub 6}. (orig.)

  6. Anodic Fabrication of Ti-Ni-O Nanotube Arrays on Shape Memory Alloy

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    2014-04-01

    Full Text Available Surface modification with oxide nanostructures is one of the efficient ways to improve physical or biomedical properties of shape memory alloys. This work reports a fabrication of highly ordered Ti-Ni-O nanotube arrays on Ti-Ni alloy substrates through pulse anodization in glycerol-based electrolytes. The effects of anodization parameters and the annealing process on the microstructures and surface morphology of Ti-Ni-O were studied using scanning electron microscope and Raman spectroscopy. The electrolyte type greatly affected the formation of nanotube arrays. A formation of anatase phase was found with the Ti-Ni-O nanotube arrays annealed at 450 °C. The oxide nanotubes could be crystallized to rutile phase after annealing treatment at 650 °C. The Ti-Ni-O nanotube arrays demonstrated an excellent thermal stability by keeping their nanotubular structures up to 650 °C.

  7. Prevention of Crevice Corrosion of STS 304 Stainless Steel by a Mg-alloy Galvanic Anode

    International Nuclear Information System (INIS)

    Lim, U. J.; Yun, B. D.; Kim, J. J.

    2006-01-01

    Prevention of crevice corrosion was studied for STS 304 stainless steel using a Mg-alloy galvanic anode in solutions with various specific resistivity. The crevice corrosion and corrosion protection characteristics of the steel was investigated by the electrochemical polarization and galvanic corrosion tests. Experimental results show that the crevice corrosion of STS 304 stainless steel does not occur in solutions of high specific resistivity, but it occurs in solutions of low specific resistivity like in solutions with resistivities of 30, 60 and 115 Ω · m. With decreasing specific resistivity of the solution, the electrode potential of STS 304 stainless steel in the crevice is lowered. The potential of STS 304 stainless steel in the crevice after coupling is cathodically polarized more by decreasing specific resistivity indicating that the crevice corrosion of STS 304 stainless steel is prevented by the Mg-alloy galvanic anode

  8. 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)

  9. Anodic solubility and electrochemical machining of hard alloys on the base of chromium and titanium carbides

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, A D; Klepikov, A N; Malofeeva, A N; Moroz, I I

    1985-01-01

    The regularities of anodic behaviour and electrochemical machining (ECM) of the samples of three materials with the following compositions: 25% of Cr/sub 3/C/sub 2/, 15% of Ni, 70% of TiC, 25% of Ni, 5% of Cr, 70% of TiC, 15% of Ni, 15% of Mo are investigated. It is shown that the electrochemical method is applicable to hard alloys machining on the base of chromium and titanium carbides, the machining of which mechanically meets serious difficulties. The alloys machining rate by a mobile cathode constitutes about 0.5 mm/min.

  10. Effect of nano Cu coating on porous Si prepared by acid etching Al-Si alloy powder

    International Nuclear Information System (INIS)

    Li, Chunli; Zhang, Ping; Jiang, Zhiyu

    2015-01-01

    As a promising anode material for lithium ion battery, nano-Cu coated porous Si powder was fabricated through two stages: first, preparation of porous nano Si fibers by acid-etching Al-Si alloy powder; second, modified by nano-Cu particles using an electroless plating method. The nano-Cu particles on the surface of nano-Si fibers, not only increase the conductivity of material, but also inhibit the fuse process between nano Si fibers during charge/discharge cycling process, resulting in increased cycling stability of the material. In 1 M LiPF 6 /EC: DMC (1:1) + 1.5 wt% VC solution at current density of 200 mA g −1 , the 150th discharge capacity of nano-Cu coated porous Si electrode was 1651 mAh g −1 with coulombic efficiency of 99%. As anode material for lithium ion battery, nano-Cu coated porous Si nano fiber material is easier to prepare, costs less, and produces higher performance, representing a promising approach for high energy lithium ion battery application

  11. Diffusivities and atomic mobilities in Cu-rich fcc Al-Cu-Mn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Ming; Du, Yong; Cui, Senlin; Xu, Honghui; Liu, Shuhong [Central South Univ., Changsha (China). State Key Laboratory of Powder Metallurgy; Zhang, Lijun [Bochum Univ. (DE). Interdisciplinary Centre for Advanced Materials Simulation (ICAMS)

    2012-07-15

    Via solid-solid diffusion couples, electron probe microanalysis and the Whittle and Green method, interdiffusivities in fcc Al-Cu-Mn alloys at 1 123 K were measured. The reliability of the obtained diffusivities is validated by comparing the computed diffusivities with literature data plus constraints among the diffusivities. Through assessments of experimentally determined diffusion coefficients by means of a diffusion-controlled transformations simulation package, the atomic mobilities of Al, Cu, and Mn in fcc Al-Cu-Mn alloys are obtained. Comprehensive comparisons between the model-predicted and the experimental data indicate that the presently obtained atomic mobilities can reproduce most of the diffusivities, concentration profiles, and diffusion paths reasonably. (orig.)

  12. 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.

  13. 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.

  14. Sputtering of two-phase AgxCuγ alloys

    International Nuclear Information System (INIS)

    Bibic, N.; Milosavljevic, M.; Perusko, D.; Wilson, I.H.

    1992-01-01

    Elemental sputtering yields from two phase AgCu alloys were measured for 20, 40 and 50 at % Ag. Argon ion bombardment energies were in the range 35-55 keV and the ion dose was 1 x 10 19 ions cm -2 . The sputtering yield for silver was found to be considerably below what was expected by simple selective sputtering of a two component alloy. Analysis by electron probe X-ray microanalysis and scanning electron microscopy of the eroded surface indicated that surface diffusion of copper from copper rich grains and geometrical constraints in the dense cone forest on Cu/Ag eutectic regions combine to reduce the sputtering yield for silver. (author)

  15. Surface tension of liquid Al-Cu binary alloys.

    OpenAIRE

    Schmitz, Julianna; Brillo, Jürgen; Egry, Ivan; Schmid-Fetzer, Rainer

    2009-01-01

    Surface tension data of liquid Al–Cu binary alloys have been measured contactlessly using the technique of electromagnetic levitation. A digital CMOS-camera (400 fps) recorded image sequences of the oscillating liquid sample and surface tensions were determined from analysis of the frequency spectra. Measurements were performed for samples covering the entire range of composition and precise data were obtained in a broad temperature range. It was found that the surface tensions can ...

  16. Performance Enhancement of Silicon Alloy-Based Anodes Using Thermally Treated Poly(amide imide) as a Polymer Binder for High Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Yang, Hwi Soo; Kim, Sang-Hyung; Kannan, Aravindaraj G; Kim, Seon Kyung; Park, Cheolho; Kim, Dong-Won

    2016-04-05

    The development of silicon-based anodes with high capacity and good cycling stability for next-generation lithium-ion batteries is a very challenging task due to the large volume changes in the electrodes during repeated cycling, which results in capacity fading. In this work, we synthesized silicon alloy as an active anode material, which was composed of silicon nanoparticles embedded in Cu-Al-Fe matrix phases. Poly(amide imide)s, (PAI)s, with different thermal treatments were used as polymer binders in the silicon alloy-based electrodes. A systematic study demonstrated that the thermal treatment of the silicon alloy electrodes at high temperature made the electrodes mechanically strong and remarkably enhanced the cycling stability compared to electrodes without thermal treatment. The silicon alloy electrode thermally treated at 400 °C initially delivered a discharge capacity of 1084 mAh g(-1) with good capacity retention and high Coulombic efficiency. This superior cycling performance was attributed to the strong adhesion of the PAI binder resulting from enhanced secondary interactions, which maintained good electrical contacts between the active materials, electronic conductors, and current collector during cycling. These findings are supported by results from X-ray photoelectron spectroscopy, scanning electron microscopy, and a surface and interfacial cutting analysis system.

  17. Cu-capped surface alloys of Pt/Cu left brace 100 right brace

    CERN Document Server

    Alshamaileh, E; Wander, A

    2003-01-01

    The room-temperature deposition of 0.5 monolayer (ML) Pt on Cu left brace 100 right brace followed by annealing to 525 K results in a sharp c(2 x 2) low-energy electron diffraction (LEED) pattern. The structure of this surface alloy is investigated by means of symmetrized automated tensor low-energy electron diffraction (SATLEED) analysis and ab initio plane wave density functional calculations. The results are then compared with those for the similar system 0.5 ML Pd/Cu left brace 100 right brace. SATLEED results for the Pt/Cu left brace 100 right brace show that it consists of an ordered c(2 x 2) Cu-Pt second layer alloy capped with a pure Cu first layer. The first and second interlayer spacings are found to be expanded by +5.1 +- 1.7 and +3.5 +- 1.7% respectively (relative to the bulk Cu interlayer spacing of 1.807 A) due to the insertion of the 8% larger Pt atoms into the second layer. The ordered mixed layer is found to be rippled by 0.08 +- 0.06 A with Pt atoms rippled outwards towards the solid-vacuum ...

  18. The quasicrystalline phase formation in Al-Cu-Cr alloys produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Sviridova, T.A.; Shevchukov, A.P.; Shelekhov, E.V. [National University of Science and Technology ' MISIS' , Moscow 119049 (Russian Federation); Diakonov, D.L. [Bardin Central Research Institute for the Iron and Steel Industry, Moscow 105005 (Russian Federation); Tcherdyntsev, V.V.; Kaloshkin, S.D. [National University of Science and Technology ' MISIS' , Moscow 119049 (Russian Federation)

    2011-06-15

    Research highlights: > Formation of decagonal quasicrystalline phase in Al-Cu-Cr alloys. > Obtained decagonal phase belongs to D{sub 3} family of decagonal quasicrystals. > Decagonal phase has 1.26 nm periodicity along 10-fold axis. > Alloys were produced by combination of mechanical alloying and subsequent annealing. > Phase composition of as-milled powders depending on annealing temperature. - Abstract: Almost single-phase decagonal quasicrystal with periodicity of 1.26 nm along 10-fold axis was produced in Al{sub 69}Cu{sub 21}Cr{sub 10} and Al{sub 72.5}Cu{sub 16.5}Cr{sub 11} alloys using combination of mechanical alloying (MA) and subsequent annealing. Phase transformations of as-milled powders depending on annealing temperature in the range of 200-800 deg. C are examined. Since the transformations can be explained based on kinetic and thermodynamic reasons it seems that applied technique (short preliminary MA followed by the annealing) permits to produce the equilibrium phases rather than metastable ones.

  19. Phases stability of shape memory alloys Cu based under irradiation

    International Nuclear Information System (INIS)

    Zelaya, Maria Eugenia

    2006-01-01

    The effects of irradiation on the relative phase stability of phases related by a martensitic transformation in copper based shape memory alloys were studied in this work.Different kind of particles and energies were employed in the irradiation experiments.The first kind of irradiation was performed with 2,6 MeV electrons, the second one with 170 keV and 300 keV Cu ions and the third one with swift heavy ions (Kr, Xe, Au) with energies between 200 and 600 MeV.Stabilization of the 18 R martensite in Cu-Zn-Al-Ni induced by electron irradiation was studied.The results were compared to those of the stabilization induced by quenching and ageing in the same alloy, and the ones obtained by irradiation in 18 R-Cu-Zn-Al alloys.The effects of Cu irradiation over b phase were analyzed with several electron microscopy techniques including: scanning electron microscopy (S E M), high resolution electron microscopy (H R E M), micro diffraction and X-ray energy dispersive spectroscopy (E D S). Structural changes in Cu-Zn-Al b phase into a closed packed structure were induced by Cu ion implantation.The closed packed structures depend on the irradiation fluence.Based on these results, the interface between these structures (closed packed and b) and the stability of disordered phases were analyzed. It was also compared the evolution of long range order in the Cu-Zn-Al and in the Cu-Zn-Al-Ni b phase as a function of fluence.The evolution of the g phase was also compared. Both results were discussed in terms of the mobility of irradiation induced point defects.Finally, the effects induced by swift heavy ions in b phase and 18 R martensite were studied. The results of the irradiation in b phase were qualitatively similar to those produced by irradiation with lower energies. On the contrary, nano metric defects were found in the irradiated 18 R martensite.These defects were characterized by H R E M.The characteristic contrast of the defects was associated to a local change in the

  20. Secondary ordering in ternary alloy CuMnPt6

    International Nuclear Information System (INIS)

    Takahashi, Miwako; Das, Ananda Kumar; Nakamura, Reo; Ohshima, Ken-ichi; Iwasaki, Hiroshi; Shishido, Toetsu

    2006-01-01

    Using the pulsed-neutron diffraction technique, we performed in situ measurements of structural ordering in the ternary alloy CuMnPt 6 . The diffraction patterns at various temperatures give a direct observation of a double-step ordering: disorder to Cu 3 Au type order as an ordering within the fundamental face-centered cubic lattice to subdivide the lattice into two sublattices formed by face-centered sites (first sublattice) and corner sites (second sublattice) at 968degC; and Cu 3 Au type order to ABC 6 type order as an ordering within the second to subdivide the lattice further into two sublattices formed by alternating (111) planes at 746degC. The order parameters for the ABC 6 type structure experimentally estimated by the method of static concentration waves indicate that the primary ordering developed almost completely, but the secondary ordering remained incomplete. (author)

  1. Analysis of precipitation in a Cu-Cr-Zr alloy

    Institute of Scientific and Technical Information of China (English)

    Zhao Mei; Lin Guobiao; Wang Zidong; Zhang Maokui

    2008-01-01

    Precipites in Cu-0.42%Cr-0.21%Zr alloy were analyzed by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM). After the solid solution was performed at 980℃ for 2 h, water-quenched and aged at 450℃ for 20 h, the precipite had a bimodal distribution of precipitate size. The coarse precipitates are pure Cr and Cu5Zr, the dispersed fine precipitate is CrCu2(Zr, Mg) and pure Cr ranging from 1 to 50 nm. The coarse phases formed during solidification and were left undissolved during solid solution. The fine precipitates are the hardening precipitates that form due to decomposition of the supersaturated solid solution during aging.

  2. Fabrication and mechanical behavior of bulk nanoporous Cu via chemical de-alloying of Cu–Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fei, E-mail: chenfei027@gmail.com [State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Chen, Xi; Zou, Lijie; Yao, Yao; Lin, Yaojun; Shen, Qiang [State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Lavernia, Enrique J. [Department of Chemical Engineering and Materials Science, University of California at Irvine, Irvine, CA 92697 (United States); Zhang, Lianmeng, E-mail: lmzhang@whut.edu.cn [State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

    2016-04-13

    We report on a study of the influence of microstructure on the mechanical behavior of bulk nanoporous Cu fabricated by chemical de-alloying of Cu{sub 50}Al{sub 50}, Cu{sub 40}Al{sub 60}, Cu{sub 33}Al{sub 67} and Cu{sub 30}Al{sub 70} (at%) alloys. The precursor Cu–Al alloys were fabricated using arc melting and bulk nanoporous Cu was obtained by subsequent de-alloying of Cu–Al alloys in 20 wt% NaOH aqueous solution at a temperature of 65 °C. We studied the microstructure of the precursor Cu–Al alloys, as well as that of the as de-alloyed bulk nanoporous Cu, using X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. Moreover, the compressive strength of bulk nanoporous Cu was measured and the relationship between microstructure and mechanical properties was studied. Our results show that the microstructure of bulk nanoporous Cu is characterized by bi-continuous interpenetrating ligament-channels with a ligament size of 130±20 nm (for Cu{sub 50}Al{sub 50}), 170±20 nm (for Cu{sub 40}Al{sub 60}) and 160±10 nm (for Cu{sub 33}Al{sub 67}). Interestingly the microstructure of de-alloyed Cu{sub 30}Al{sub 70} is bimodal with nanopores (100's nm) and interspersed featureless regions a few microns in size. The compressive strength increased with decreasing volume fraction of porosity; as porosity increased 56.3±2% to 73.9±2%, the compressive strength decreased from 17.18±1 MPa to 2.71±0.5 MPa.

  3. Effect of protein adsorption on the corrosion behavior of 70Cu-30Ni alloy in artificial seawater.

    Science.gov (United States)

    Torres Bautista, Blanca E; Carvalho, Maria L; Seyeux, Antoine; Zanna, Sandrine; Cristiani, Pierangela; Tribollet, Bernard; Marcus, Philippe; Frateur, Isabelle

    2014-06-01

    Copper alloys often used in cooling circuits of industrial plants can be affected by biocorrosion induced by biofilm formation. The objective of this work was to study the influence of protein adsorption, which is the first step in biofilm formation, on the electrochemical behavior of 70Cu-30Ni (wt.%) alloy in static artificial seawater and on the chemical composition of oxide layers. For that purpose, electrochemical measurements performed after 1h of immersion were combined to surface analyses. A model is proposed to analyze impedance data. In the presence of bovine serum albumin (BSA, model protein), the anodic charge transfer resistance deduced from EIS data at Ecorr is slightly higher, corresponding to lower corrosion current. Without BSA, two oxidized layers are shown by XPS and ToF-SIMS: an outer layer mainly composed of copper oxide (Cu2O redeposited layer) and an inner layer mainly composed of oxidized nickel, with a global thickness of ~30nm. The presence of BSA leads to a mixed oxide layer (CuO, Cu2O, Ni(OH)2) with a lower thickness (~10nm). Thus, the protein induces a decrease of the dissolution rate at Ecorr and hence a decrease of the amount of redeposited Cu2O and of the oxide layer thickness. © 2013.

  4. Novel method for controllable fabrication of a superhydrophobic CuO surface on AZ91D magnesium alloy.

    Science.gov (United States)

    She, Zuxin; Li, Qing; Wang, Zhongwei; Li, Longqin; Chen, Funan; Zhou, Juncen

    2012-08-01

    A novel method for controllable fabrication of a superhydrophobic CuO surface on AZ91D magnesium alloy is reported in this paper. Hierarchical structure composed of micro/nano-featherlike CuO was obtained by electrodeposition of Cu-Zn alloy coating and subsequently an electrochemical anodic treatment in alkaline solution. After modification with lauric acid, the surface became hydrophobicity/superhydrophobicity. The formation of featherlike CuO structures was controllable by varying the coating composition. By applying SEM, ICP-AES, and water contact angle analysis, the effects of coating composition on the surface morphology and hydrophobicity of the as-prepared surfaces were detailedly studied. The results indicated that at the optimal condition, the surface showed a good superhydrophobicity with a water contact angle as high as 155.5 ± 1.3° and a sliding angle as low as about 3°. Possible growth mechanism of featherlike CuO hierarchical structure was discussed. Additionally, the anticorrosion effect of the superhydrophobic surface was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The interface model for anticorrosion mechanism of superhydrophobic surface in corrosive medium was proposed. Besides, the mechanical stability test indicated that the resulting superhydrophobic surfaces have good mechanical stability.

  5. 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...

  6. 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)

  7. 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.

  8. Laser deposition of (Cu + Mo) alloying reinforcements on AA1200 substrate for corrosion improvement

    CSIR Research Space (South Africa)

    Popoola, API

    2011-10-01

    Full Text Available Poor corrosion performance of aluminium alloys in marine environment has been a subject of intensive research recently. Aluminium substrate was alloyed with a combination of two metallic powders (Cu + Mo) using an Nd: YAG solid state laser...

  9. Structure and coercivity of nanocrystalline Fe–Si–B–Nb–Cu alloys

    Indian Academy of Sciences (India)

    Unknown

    Fe–Si–B–Nb–Cu alloy; melt-spinning; crystallization; nanocrystalline ... to possess a unique combination of soft magnetic properties ... meability and high electrical resistivity (Yoshizawa et al ... ture and thermal stability of the alloy ribbons.

  10. Synthesis and Electrocatalytic Performance of Multi-Component Nanoporous PtRuCuW Alloy for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Xiaoting Chen

    2015-06-01

    Full Text Available We have prepared a multi-component nanoporous PtRuCuW (np-PtRuCuW electrocatalyst via a combined chemical dealloying and mechanical alloying process. The X-ray diffraction (XRD, transmission electron microscopy (TEM and electrochemical measurements have been applied to characterize the microstructure and electrocatalytic activities of the np-PtRuCuW. The np-PtRuCuW catalyst has a unique three-dimensional bi-continuous ligament structure and the length scale is 2.0 ± 0.3 nm. The np-PtRuCuW catalyst shows a relatively high level of activity normalized to mass (467.1 mA mgPt−1 and electrochemically active surface area (1.8 mA cm−2 compared to the state-of-the-art commercial PtC and PtRu catalyst at anode. Although the CO stripping peak of np-PtRuCuW 0.47 V (vs. saturated calomel electrode, SCE is more positive than PtRu, there is a 200 mV negative shift compared to PtC (0.67 V vs. SCE. In addition, the half-wave potential and specific activity towards oxygen reduction of np-PtRuCuW are 0.877 V (vs. reversible hydrogen electrode, RHE and 0.26 mA cm−2, indicating a great enhancement towards oxygen reduction than the commercial PtC.

  11. Systematic corrosion investigation of various Cu-Sn alloys electrodeposited on mild steel in acidic solution: Dependence of alloy composition

    Energy Technology Data Exchange (ETDEWEB)

    Suerme, Yavuz, E-mail: ysurme@nigde.edu.t [Department of Chemistry, Faculty of Science and Art, Nigde University, 51200 Nigde (Turkey); Guerten, A. Ali [Department of Chemistry, Faculty of Science and Art, Osmaniye Korkut Ata University, 80000 Osmaniye (Turkey); Bayol, Emel; Ersoy, Ersay [Department of Chemistry, Faculty of Science and Art, Nigde University, 51200 Nigde (Turkey)

    2009-10-19

    Copper-tin alloy films were galvanostatically electrodeposited on the mild steel (MS) by combining the different amount of Cu and Sn electrolytes at a constant temperature (55 deg. C) and pH (3.5). Alloy films were characterized by using the energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and micrographing techniques. Corrosion behaviours were evaluated with electrochemical impedance spectrometry (EIS) and electrochemical polarization measurements. Time gradient of electrolysis process was adjusted to obtain same thickness of investigated alloys on MS. The systematic corrosion investigation of various Cu{sub x}-Sn{sub 100-x} (x = 0-100) alloy depositions on MS substrate were carried out in 0.1 M sulphuric acid medium. Results indicate that the corrosion resistance of the alloy coatings depended on the alloy composition, and the corrosion resistance increased at Cu-Sn alloy deposits in proportion to Sn ratio.

  12. Formation of titanium dioxide nanotubes on Ti–30Nb–xTa alloys by anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Sil [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Jeong, Yong-Hoon [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Biomechanics and Tissue Engineering Laboratory, Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Brantley, William A. [Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, The Ohio State University, Columbus, OH (United States)

    2013-12-31

    The goal of this study was to investigate the formation of titanium dioxide nanotubes on the surface of cast Ti–30Nb–xTa alloys by anodizing. The anodization technique for creating the nanotubes utilized a potentiostat and an electrolyte containing 1 M H{sub 3}PO{sub 4} with 0.8 wt.% NaF. The grain size of the Ti–30Nb–xTa alloys increased as the Ta content increased. Using X-ray diffraction, for the Ti–30Nb alloy the main peaks were identified as α″ martensite with strong peaks of β phase. The phases in the Ti–30Nb–xTa alloys changed from a duplex (α″ + β) microstructure to solely β phase with increasing Ta content. The nanotubes that formed on the surface of the Ti–30Nb–xTa alloys were amorphous TiO{sub 2} without an evidence of the crystalline anatase or rutile forms of TiO{sub 2}. Scanning electron microscopy revealed that the average diameters of the small and large nanotubes on the Ti–30Nb alloy not containing Ta were approximately 100 nm and 400 nm, respectively, whereas the small and large nanotubes on the alloy had diameters of approximately 85 nm and 300 nm, respectively. As the Ta content increased from 0 to 15 wt.%, the average lengths of the nanotubes increased from 2 μm to 3.5 μm. Energy-dispersive X-ray spectroscopy indicated that the nanotubes were principally composed of Ti, Nb, Ta, O and F. Contact angle measurements showed that the nanotube surface had good wettability by water droplets. - Highlights: • TiO{sub 2} nanotube layers on anodized Ti-30Nb-xTa alloys have been investigated. • Nanotube surface had an amorphous structure without heat treatment. • Nanotube diameter of Ti-30Nb-xTa decreased, whereas tube layer increased with Ta content. • The nanotube surface exhibited the low contact angle and good wettability.

  13. Formation of titanium dioxide nanotubes on Ti–30Nb–xTa alloys by anodizing

    International Nuclear Information System (INIS)

    Kim, Eun-Sil; Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

    2013-01-01

    The goal of this study was to investigate the formation of titanium dioxide nanotubes on the surface of cast Ti–30Nb–xTa alloys by anodizing. The anodization technique for creating the nanotubes utilized a potentiostat and an electrolyte containing 1 M H 3 PO 4 with 0.8 wt.% NaF. The grain size of the Ti–30Nb–xTa alloys increased as the Ta content increased. Using X-ray diffraction, for the Ti–30Nb alloy the main peaks were identified as α″ martensite with strong peaks of β phase. The phases in the Ti–30Nb–xTa alloys changed from a duplex (α″ + β) microstructure to solely β phase with increasing Ta content. The nanotubes that formed on the surface of the Ti–30Nb–xTa alloys were amorphous TiO 2 without an evidence of the crystalline anatase or rutile forms of TiO 2 . Scanning electron microscopy revealed that the average diameters of the small and large nanotubes on the Ti–30Nb alloy not containing Ta were approximately 100 nm and 400 nm, respectively, whereas the small and large nanotubes on the alloy had diameters of approximately 85 nm and 300 nm, respectively. As the Ta content increased from 0 to 15 wt.%, the average lengths of the nanotubes increased from 2 μm to 3.5 μm. Energy-dispersive X-ray spectroscopy indicated that the nanotubes were principally composed of Ti, Nb, Ta, O and F. Contact angle measurements showed that the nanotube surface had good wettability by water droplets. - Highlights: • TiO 2 nanotube layers on anodized Ti-30Nb-xTa alloys have been investigated. • Nanotube surface had an amorphous structure without heat treatment. • Nanotube diameter of Ti-30Nb-xTa decreased, whereas tube layer increased with Ta content. • The nanotube surface exhibited the low contact angle and good wettability

  14. Boric/sulfuric acid anodizing of aluminum alloys 2024 and 7075: Film growth and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, G.E.; Zhang, L.; Smith, C.J.E.; Skeldon, P.

    1999-11-01

    The influence of boric acid (H{sub 3}BO{sub 3}) additions to sulfuric acid (H{sub 2}SO{sub 4}) were examined for the anodizing of Al 2024-T3 (UNS A92024) and Al 7075-T6 (UNS A97075) alloys at constant voltage. Alloys were pretreated by electropolishing, by sodium dichromate (Na{sub 2}Cr{sub 2}O{sub 7})/H{sub 2}SO{sub 4} (CSA) etching, or by alkaline etching. Current-time responses revealed insignificant dependence on the concentration of H{sub 3}BO{sub 3} to 50 g/L. Pretreatments affected the initial film development prior to the establishment of the steady-state morphology of the porous film, which was related to the different compositions and morphologies of pretreated surfaces. More detailed studies of the Al 7075-T6 alloy indicated negligible effects of H{sub 3}BO{sub 3} on the coating weight, morphology of the anodic film, and thickening rate of the film, or corrosion resistance provided by the film. In salt spray tests, unsealed films formed in H{sub 2}SO{sub 4} or mixed acid yielded similar poor corrosion resistances, which were inferior to that provided by anodizing in chromic acid (H{sub 2}CrO{sub 4}). Sealing of films in deionized water, or preferably in chromate solution, improved corrosion resistance, although not matching the far superior performance provided by H{sub 2}CrO{sub 4} anodizing and sealing.

  15. Effect of Annealing on the Pitting Corrosion Resistance of Anodized Aluminum-Magnesium Alloy Processed by Equal Channel Angular Pressing

    Energy Technology Data Exchange (ETDEWEB)

    Son, In Joon; Nakano, Hiroaki; Oue, Satoshi; Fukushima, Hisaaki; Horita, Zenji [Kyushu University, Fukuoka (Japan); Kobayashi, Shigeo [Kyushu Sangyo University, Fukuoka (Japan)

    2007-12-15

    The effect of annealing on the pitting corrosion resistance of anodized Al-Mg alloy (AA5052) processed by equal-channel angular pressing (ECAP) was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl{sub 3} and also by surface analysis. The Al-Mg alloy was annealed at a fixed temperature between 473 and 573 K for 120 min in air after ECAP. Anodizing was conducted for 40 min at 100-400 A/m{sup 2} at 293 K in a solution containing 1.53 mol/L of H{sub 2}SO{sub 4} and 0.0185 mol/L of Al{sub 2}(SO{sub 4}){sub 3}. The internal stress generated in anodic oxide films during anodization was measured with a strain gauge to clarify the effect of ECAP on the pitting corrosion resistance of anodized Al-Mg alloy. The time required to initiate the pitting corrosion of anodized Al-Mg alloy was shorter in samples subjected to ECAP, indicating that ECAP decreased the pitting corrosion resistance. however, the pitting corrosion resistance was greatly improved by annealing after ECAP. The time required to initiate pitting corrosion increased with increasing annealing temperature. The strain gauge attached to Al-Mg alloy revealed that the internal stress present in the anodic oxide films was compressive stress, and that the stress was larger with ECAP than without. The compressive internal stress gradually decreased with increasing annealing temperature. Scanning electron microscopy showed that cracks occurred in the anodic oxide film on Al-Mg alloy during initial corrosion and that the cracks were larger with ECAP than without. The ECAP process of severe plastic deformation produces large internal stresses in the Al-Mg alloy: the stresses remain in the anodic oxide films, increasing the likelihood of cracks. it is assumed that the pitting corrosion is promoted by these cracks as a result of the higher internal stress resulting from ECAP. The improvement in the pitting corrosion resistance of anodized AlMg alloy as a result of annealing appears to be

  16. Effect of Annealing on the Pitting Corrosion Resistance of Anodized Aluminum-Magnesium Alloy Processed by Equal Channel Angular Pressing

    International Nuclear Information System (INIS)

    Son, In Joon; Nakano, Hiroaki; Oue, Satoshi; Fukushima, Hisaaki; Horita, Zenji; Kobayashi, Shigeo

    2007-01-01

    The effect of annealing on the pitting corrosion resistance of anodized Al-Mg alloy (AA5052) processed by equal-channel angular pressing (ECAP) was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl 3 and also by surface analysis. The Al-Mg alloy was annealed at a fixed temperature between 473 and 573 K for 120 min in air after ECAP. Anodizing was conducted for 40 min at 100-400 A/m 2 at 293 K in a solution containing 1.53 mol/L of H 2 SO 4 and 0.0185 mol/L of Al 2 (SO 4 ) 3 . The internal stress generated in anodic oxide films during anodization was measured with a strain gauge to clarify the effect of ECAP on the pitting corrosion resistance of anodized Al-Mg alloy. The time required to initiate the pitting corrosion of anodized Al-Mg alloy was shorter in samples subjected to ECAP, indicating that ECAP decreased the pitting corrosion resistance. however, the pitting corrosion resistance was greatly improved by annealing after ECAP. The time required to initiate pitting corrosion increased with increasing annealing temperature. The strain gauge attached to Al-Mg alloy revealed that the internal stress present in the anodic oxide films was compressive stress, and that the stress was larger with ECAP than without. The compressive internal stress gradually decreased with increasing annealing temperature. Scanning electron microscopy showed that cracks occurred in the anodic oxide film on Al-Mg alloy during initial corrosion and that the cracks were larger with ECAP than without. The ECAP process of severe plastic deformation produces large internal stresses in the Al-Mg alloy: the stresses remain in the anodic oxide films, increasing the likelihood of cracks. it is assumed that the pitting corrosion is promoted by these cracks as a result of the higher internal stress resulting from ECAP. The improvement in the pitting corrosion resistance of anodized AlMg alloy as a result of annealing appears to be attributable to a decrease in

  17. Study of anodic dissolution of Fe-Ru alloy with the aid of mossbauer spectroscopy

    International Nuclear Information System (INIS)

    Khlystov, A.S.; Fasman, A.B.; Kil'dibekova, G.A.

    1986-01-01

    This paper uses Fe 57 Mossbauer spectroscopy, whereby iron compounds may be identified quantitatively and their composition and structure can be determined, for the study of the relationships of slime formation from Fe-Ru binary alloys. Both the products of dissolution and the composition and state of intermediate phases formed at various stages of anodic dissolution were studied simultaneously. It was found that the slimes formed both during chemical and during electrochemical destruction of ruthenium-iron alloys are finely dispersed systems of complex composition, analogous to those formed in the course of electrochemical dissolution of Ni-Ru alloys, which were found to contain oxide phases of ruthenium (by x-ray spectroscopy and ESCA) and of nickel (by x-ray phase analysis). The difference between the slime compositions is determined mainly by kinetic factors

  18. Aluminum alloy for cladding excellent in sacrificial anode property and erosion-corrosion resistance

    International Nuclear Information System (INIS)

    Imaizumi, S.; Mikami, K.; Yamada, K.

    1980-01-01

    An aluminum alloy for cladding excellent in sacrificial anode property and erosion-corrosion resistance, which consists essentially of, in weight percentage: zinc - 0.3 to 3.0%, magnesium - 0.2 to 4.0%, manganese - 0.3 to 2.0%, and, the balance aluminum and incidental impurities; said alloy including an aluminum alloy also containing at least one element selected from the group consisting of, in weight percentage: indium - 0.005 to 0.2%, tin - 0.01 to 0.3%, and, bismuth - 0.01 to 0.3%; provided that the total content of indium, tin and bismuth being up to 0.3%

  19. Abnormal magnetization behaviors in Sm–Ni–Fe–Cu alloys

    International Nuclear Information System (INIS)

    Yang, W.Y.; Zhang, Y.F.; Zhao, H.; Chen, G.F.; Zhang, Y.; Du, H.L.; Liu, S.Q.; Wang, C.S.; Han, J.Z.; Yang, Y.C.; Yang, J.B.

    2016-01-01

    The magnetization behaviors in Sm–Ni–Fe–Cu alloys at low temperatures have been investigated. It was found that the hysteresis loops show wasp-waisted character at low temperatures, which has been proved to be related to the existence of multi-phases, the Fe/Ni soft magnetic phases and the CaCu 5 -type hard magnetic phase. A smooth-jump behavior of the magnetization is observed at T>5 K, whereas a step-like magnetization process appears at T<5 K. The CaCu 5 -type phase is responsible for such abnormal magnetization behavior. The magnetic moment reversal model with thermal activation is used to explain the relation of the critical magnetic field (H cm ) to the temperature (T>5 K). The reversal of the moment direction has to cross over an energy barrier of about 6.6×10 −15 erg. The step-like jumps of the magnetization below 5 K is proposed to be resulted from a sharp increase of the sample temperature under the heat released by the irreversible domain wall motion. - Highlights: • Two different magnetization mechanisms, controlled by temperature, have been found in the Sm–Ni–Fe–Cu alloys. The smooth-jump behavior of the magnetization is observed at T>5 K and the step-like magnetization process appears at T<5 K. • The magnetic moment reversal model with thermal activation has been successfully used to explain the relation of the critical magnetic field (H cm ) to the temperature (T>5 K). The energy barrier for the reversal of the moment direction has been found to be about 6.6×10 −15 erg. • The transition field for the step-like jumps is very strict, independent from the magnetic sweep rate. This is remarkably different from the similar step-like jump behavior in reference [20]. • According to the SEM images and EDX analysis, two kinds of regions are found in the alloys. The Fe–Ni–Cu regions are surrounded by the 1:5 Sm–Ni–Fe–Cu regions and shows fish-bone like structure. An interesting thing is that the Fe–Ni–Cu regions are

  20. Nanoporous alumina formed by self-organized two-step anodization of Ni3Al intermetallic alloy in citric acid

    International Nuclear Information System (INIS)

    Stępniowski, Wojciech J.; Cieślak, Grzegorz; Norek, Małgorzata; Karczewski, Krzysztof; Michalska-Domańska, Marta; Zasada, Dariusz; Polkowski, Wojciech; Jóźwik, Paweł; Bojar, Zbigniew

    2013-01-01

    Highlights: ► Anodic porous alumina was formed by Ni 3 Al intermetallic alloy anodization. ► The anodizations were conducted in 0.3 M citric acid. ► Nanopores geometry depends on anodizing voltage. ► No barrier layer was formed during anodization. - Abstract: Formation of the nanoporous alumina on the surface of Ni 3 Al intermetallic alloy has been studied in details and compared with anodization of aluminum. Successful self-organized anodization of this alloy was performed in 0.3 M citric acid at voltages ranging from 2.0 to 12.0 V using a typical two-electrode cell. Current density records revealed different mechanism of the porous oxide growth when compared to the mechanism pertinent for the anodization of aluminum. Electrochemical impedance spectroscopy experiments confirmed the differences in anodic oxide growth. Surface and cross-sections of the Ni 3 Al intermetallic alloy with anodic oxide were observed with field-emission scanning electron microscope and characterized with appropriate software. Nanoporous oxide growth rate was estimated from cross-sectional FE-SEM images. The lowest growth rate of 0.14 μm/h was found for the anodization at 0 °C and 2.0 V. The highest one – 2.29 μm/h – was noticed for 10.0 V and 30 °C. Pore diameter was ranging from 18.9 nm (2.0 V, 0 °C) to 32.0 nm (12.0 V, 0 °C). Interpore distance of the nanoporous alumina was ranging from 56.6 nm (2.0 V, 0 °C) to 177.9 nm (12.0 V, 30 °C). Pore density (number of pore occupying given area) was decreasing with anodizing voltage increase from 394.5 pores/μm 2 (2.0 V, 0 °C) to 94.9 pores/μm 2 (12.0 V, 0 °C). All the geometrical features of the anodic alumina formed by two-step self-organized anodization of Ni 3 Al intermetallic alloy are depending on the operating conditions.

  1. ROLE OF ULTRASOUND IN MECHANISMS OF ANODE-CATHODE INTERACTIONS DURING ELECTROSPARK ALLOYING

    Directory of Open Access Journals (Sweden)

    N. M. Chigrinova

    2016-01-01

    Full Text Available The paper reveals results of investigations on mass transfer kinetics and dynamics of coating formation while using integral electrospark alloying method with additional ultrasonic exposure at different stages of formation. Nowadays, a classical method for electrospark alloying with hard-alloy anodes and impulse AC voltage frequency on the vibration exciter coil from 20 to 1600 Hz has been mainly used for application of protective and strengthening coatings within permissible thickness and characteristics. The key aspect of ultrasonic exposure application (frequency 22–44 kHz during electrospark alloying is the possibility to increase further thickness of coatings to be formed even after reaching a brittle fracture threshold of the coating material. Methodology of the executed research activity has been based on integrated studies (gravimetric, metallographic, X-ray diffraction and electron microscopic of coatings which are to be formed through compositions produced while using method of high-energy hot compaction and a “refractory carbide (WC and a binding material“ system in the form of alloy based on nickel from the series of “colmonoy” Ni – Ni3B system which is alloyed with additions of copper and silicon. The initial surface treatment within ultrasonic frequency range (22–44 kHz contributes to a noticeable increase in the mass transfer rate, which is primarily determined by chemical composition and thermodynamic stability of anodes. It is due to surface activation in the process of its preliminary deformation at ultrasonic frequency which creates additional conditions for striking of a spark.The final ultrasonic treatment improves coating quality due to its additional forging that leads to an increase of its structure homogeneity and density.

  2. 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.

  3. Anodic Behavior of Alloy 22 in Calcium Chloride and in Calcium Chloride Plus Calcium Nitrate Brines

    International Nuclear Information System (INIS)

    Evans, K.J.; Day, S.D.; Ilevbare, G.O.; Whalen, M.T.; King, K.J.; Hust, G.A.; Wong, L.L.; Estill, J.C.; Rebak, R.B.

    2003-01-01

    Alloy 22 (UNS N60622) is a nickel-based alloy, which is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in concentrated calcium chloride (CaCl 2 ) brines and to evaluate the inhibitive effect of nitrate, especially to localized corrosion. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion potential of Alloy 22 was approximately -360 mV in the silver-silver chloride (SSC) scale and independent of the tested temperature. Cyclic polarization tests showed that Alloy 22 was mainly susceptible to localized attack in 5 M CaCl 2 at 75 C and higher temperatures. The addition of nitrate in a molar ratio of chloride to nitrate equal to 10 increased the onset of localized corrosion to approximately 105 C. The addition of nitrate to the solution also decreased the uniform corrosion rate and the passive current of the alloy

  4. A Practical Anodic and Cathodic Curve Intersection Model to Understand Multiple Corrosion Potentials of Fe-Based Glassy Alloys in OH- Contained Solutions.

    Science.gov (United States)

    Li, Y J; Wang, Y G; An, B; Xu, H; Liu, Y; Zhang, L C; Ma, H Y; Wang, W M

    2016-01-01

    A practical anodic and cathodic curve intersection model, which consisted of an apparent anodic curve and an imaginary cathodic line, was proposed to explain multiple corrosion potentials occurred in potentiodynamic polarization curves of Fe-based glassy alloys in alkaline solution. The apparent anodic curve was selected from the measured anodic curves. The imaginary cathodic line was obtained by linearly fitting the differences of anodic curves and can be moved evenly or rotated to predict the number and value of corrosion potentials.

  5. The Incorporation of Lithium Alloying Metals into Carbon Matrices for Lithium Ion Battery Anodes

    Science.gov (United States)

    Hays, Kevin A.

    An increased interest in renewable energies and alternative fuels has led to recognition of the necessity of wide scale adoption of the electric vehicle. Automotive manufacturers have striven to produce an electric vehicle that can match the range of their petroleum-fueled counterparts. However, the state-of-the-art lithium ion batteries used to power the current offerings still do not come close to the necessary energy density. The energy and power densities of the lithium ion batteries must be increased significantly if they are going to make electric vehicles a viable option. The chemistry of the lithium ion battery, based on lithium cobalt oxide cathodes and graphite anodes, is limited by the amount of lithium the cathode can provide and the anode will accept. While these materials have proven themselves in portable electronics over the past two decades, plausible higher energy alternatives do exist. The focus is of this study is on anode materials that could achieve a capacity of more than 3 times greater than that of graphite anodes. The lithium alloying anode materials investigated and reported herein include tin, arsenic, and gallium arsenide. These metals were synthesized with nanoscale dimensions, improving their electrochemical and mechanical properties. Each exhibits their own benefits and challenges, but all display opportunities for incorporation in lithium ion batteries. Tin is incorporated in multilayer graphene nanoshells by introducing small amounts of metal in the core and, separately, on the outside of these spheres. Electrolyte decomposition on the anode limits cycle life of the tin cores, however, tin vii oxides introduced outside of the multilayer graphene nanoshells have greatly improved long term battery performance. Arsenic is a lithium alloying metal that has largely been ignored by the research community to date. One of the first long term battery performance tests of arsenic is reported in this thesis. Anodes were made from nanoscale

  6. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    OpenAIRE

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-01-01

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these allo...

  7. 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.

  8. Cu2+1O coated polycrystalline Si nanoparticles as anode for lithium-ion battery.

    Science.gov (United States)

    Zhang, Junying; Zhang, Chunqian; Wu, Shouming; Liu, Zhi; Zheng, Jun; Zuo, Yuhua; Xue, Chunlai; Li, Chuanbo; Cheng, Buwen

    2016-12-01

    Cu2+1O coated Si nanoparticles were prepared by simple hydrolysis and were investigated as an anode material for lithium-ion battery. The coating of Cu2+1O on the surface of Si particles remarkably improves the cycle performance of the battery than that made by the pristine Si. The battery exhibits an initial reversible capacity of 3063 mAh/g and an initial coulombic efficiency (CE) of 82.9 %. With a current density of 300 mA/g, its reversible capacity can remains 1060 mAh/g after 350 cycles, corresponding to a CE ≥ 99.8 %. It is believed that the Cu2+1O coating enhances the electrical conductivity, and the elasticity of Cu2+1O further helps buffer the volume changes during lithiation/delithiation processes. Experiment results indicate that the electrode maintained a highly integrated structure after 100 cycles and it is in favour of the formation of stable solid electrolyte interface (SEI) on the Si surface to keep the extremely high CE during long charge and discharge cycles.

  9. Effect of solute Cu on ductile-to-brittle behavior of martensitic Fe-8% Ni alloy

    International Nuclear Information System (INIS)

    Junaidi Syarif; Tsuchiyama, Toshihiro; Takaki, Setsuo

    2007-01-01

    Effect of solute Cu on the ductile-to-brittle (DBT) behaviour of martensitic Fe-8mass%Ni alloy is investigated to understand the effect of solute Cu on mechanical properties of martensitic steel. The DBT behaviours of the Fe-8mass%Ni and the Fe-8mass%Ni-1mass%Cu alloys are almost the same. It is thought to be due to disappearance of the solid solution softening in the martensitic Fe-8mass%Ni-Cu alloys. The solute Cu gives small influence on temperature and strain rate dependences of yield stress and suppressing the twin deformation at lower temperature in the martensitic Fe-8mass%Ni alloy. Therefore, the DBT temperature of the martensitic Fe-8mass%Ni-Cu alloy was not shifted to lower side. (author)

  10. Electrochemical Random Signal Analysis during Localized Corrosion of Anodized 1100 Aluminum Alloy in Chloride Environments

    International Nuclear Information System (INIS)

    Sakairi, M.; Shimoyama, Y.; Nagasawa, D.

    2008-01-01

    A new type of electrochemical random signal (electrochemical noise) analysis technique was applied to localized corrosion of anodic oxide film formed 1100 aluminum alloy in 0.5 kmol/m 3 H 3 BO 4 /0.05 kmol/m 3 Na 2 B 4 O 7 with 0.01 kmol/m 3 NaCl. The effect of anodic oxide film structure, barrier type, porous type, and composite type on galvanic corrosion resistance was also examined. Before localized corrosion started, incubation period for pitting corrosion, both current and potential slightly change as initial value with time. The incubation period of porous type anodic oxide specimens are longer than that of barrier type anodic oxide specimens. While pitting corrosion, the current and potential were changed with fluctuations and the potential and the current fluctuations show a good correlation. The records of the current and potential were processed by calculating the power spectrum density (PSD) by the Fast Fourier Transform (FFT) method. The potential and current PSD decrease with increasing frequency, and the slopes are steeper than or equal to minus one (-1). This technique allows observation of electrochemical impedance changes during localized corrosion

  11. Electrical Properties of a Thin Anodized Capacitor Made of Y-Doped Al Alloy Film

    Science.gov (United States)

    Onozuka, Tomotake; Sasaki, Hayato; Mikuni, Naohiro; Shinkai, Satoko; Sasaki, Katsutaka; Yamane, Misao; Abe, Yoshio

    2005-09-01

    We have prepared an Al-Y anodized capacitor using sputter-deposited Al-Y alloy film with 5 at. % Y atoms, and evaluated the capacitor properties and the leakage current properties before and after heat treatment. In addition, the characterization of Al-Y anodized films was examined by X-ray diffraction, Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy analyses. As a result, it is revealed that the thermal stability of an Al-Y anodized capacitor is superior to that of a pure Al anodized capacitor because of its excellent passive nature, and the loss properties can be improved by increasing the heat treatment temperature in air because of the reduction of the equivalent series resistance. Furthermore, it is clarified that the cause of the short-circuited state observed at 550°C is the formation of a narrow capillary-like conduction path of metallic Al atoms as a result of the interdiffusion of Al.

  12. Grindability of dental cast Ti-Ag and Ti-Cu alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takahashi, Masatoshi; Okabe, Toru; Okuno, Osamu

    2003-06-01

    Experimental Ti-Ag alloys (5, 10, and 20 mass% Ag) and Ti-Cu alloys (2, 5, and 10 mass% Cu) were cast into magnesia molds using a dental casting machine, and their grindability was investigated. At the lowest grinding speed (500 m min(-1)), there were no statistical differences among the grindability values of the titanium and titanium alloys. The grindability of the alloys increased as the grinding speed increased. At the highest grinding speed (1500 m x min(-1)), the grindability of the 20% Ag, 5% Cu, and 10% Cu alloys was significantly higher than that of titanium. It was found that alloying with silver or copper improved the grindability of titanium, particularly at a high speed. It appeared that the decrease in elongation caused by the precipitation of small amounts of intermetallic compounds primarily contributed to the favorable grindability of the experimental alloys.

  13. Relationship between Microstructure and Properties of Cu-Cr-Ag-(Ce) Alloy Using Microscopic Investigation.

    Science.gov (United States)

    Chen, Huiming; Yuan, Dawei; Wu, Shanjiang; Wang, Hang; Xie, Weibin; Yang, Bin

    2017-01-01

    Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

  14. Mechanical alloying of Cu-xCr (x = 3, 5 and 8 wt.%) alloys

    International Nuclear Information System (INIS)

    Aguilar, C.; Ordonez, S.; Guzman, D.; Rojas, P.A.

    2010-01-01

    This work studies the structural evolution of Cu-xCr (x = 3, 5 and 8 wt.%) alloys processed by mechanical alloying using X-ray diffraction profiles, scanning microscopy and microhardness analysis. X-ray diffraction analysis using the modified Williamson-Hall and Warren-Averbach methods were used to determine structural properties, such as crystallite size, stacking fault probability and energy, dislocation density, lattice parameters and crystallite size distribution of metallic powder as a function of Cr amount and milling time. Lattice defects increase the Gibbs free energy and the Gibbs free energy curves shift upward, therefore the solubility limit change.

  15. The intergranular corrosion behavior of 6000-series alloys with different Mg/Si and Cu content

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Yun; Liu, Qing, E-mail: qingliu@cqu.edu.cn; Jia, Zhihong, E-mail: zhihongjia@cqu.edu.cn; Xing, Yuan; Ding, Lipeng; Wang, Xueli

    2017-05-31

    Highlights: • High Cu alloy with high Mg/Si ratio has the best comprehensive property. • Addition of excess Mg could improve the intergranular corrosion resistance. • Si containing particles on the grain boundaries of Si-rich alloys promote IGC. • IGC susceptibility depends primarily on Cu content and secondarily on Mg/Si ratio. - Abstract: 6000-series aluminium alloys with high Cu or excess Si addition were susceptible to intergranular corrosion (IGC). In order to obtain good IGC resistance, four alloys with low/high Cu and various Mg/Si ratios were designed. The corrosion behaviour of four alloys was investigated by accelerated corrosion test, electrochemical test and electron microscopies. It was revealed that IGC susceptibility of alloys was the result of microgalvanic coupling between the noble grain boundary precipitates and the adjacent precipitates free zone (PFZ), which was closely related to a combination of Cu content and the Mg/Si ratio. Excess Mg could improve the IGC resistance of alloys by forming discontinuous precipitates on the grain boundaries. The designed alloy with high Cu and excess Mg has the same corrosion level as the commercial alloy with low Cu and excess Si, which provides possibility for developing new alloy.

  16. 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.

  17. Anodic galvanostatic polarization of AA2024-T3 aircraft alloy in conventional mineral acids

    Energy Technology Data Exchange (ETDEWEB)

    Kozhukharov, S., E-mail: stephko1980@abv.bg [Department of Chemical Sciences, University of Chemical Technology and Metallurgy, 8 “Kliment Okhridski” Blvd, 1756, Sofia (Bulgaria); Girginov, Ch. [Department of Chemical Sciences, University of Chemical Technology and Metallurgy, 8 “Kliment Okhridski” Blvd, 1756, Sofia (Bulgaria); Avramova, I. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Science, 11 “Georgi Bonchev” Str., 1113, Sofia (Bulgaria); Machkova, M. [Department of Chemical Sciences, University of Chemical Technology and Metallurgy, 8 “Kliment Okhridski” Blvd, 1756, Sofia (Bulgaria)

    2016-09-01

    The present study is devoted to the determination of the impact of the anodization of AA2024-T3 alloys in HCl, HNO{sub 3}, H{sub 2}SO{sub 4} or H{sub 3}PO{sub 4} on the samples’ surface morphology and properties. Subsequent systematic assessments were performed by Scanning Electron Microscopy (SEM), Energy Dispersion X-Ray Spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS). These observations were combined with Linear Voltammetry (LVA) and Electrochemical Impedance Spectroscopy (EIS) after 48 and 168 h of exposure to a 3.5% NaCl model corrosive medium. The main result is, that completely different effects were observed in accordance to the acid used. It was established that the monoprotonic acids have a deep destructive effect due to dissolution of the alloy components, whereas the polyprotonic ones possess either indistinguishable influence, or surface film formation. - Highlights: • AA2024 was polarized anodically in 15%{sub wt} acid solutions at 15 mA cm{sup −2} for 2 h. • Four mineral acids were selected for investigation: HCl, HNO{sub 3}, H{sub 2}SO{sub 4} and H{sub 3}PO{sub 4}. • SEM, EDX and XPS were applied for morphological description. • Electrochemical characterizations were performed by EIS and linear voltammetry. • The acid used predetermines completely different interaction with the AA2024 alloy.

  18. Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers for Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Michael D. Blanton

    2012-09-01

    Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

  19. Anodic behaviours, dissolution and passivation of iron-nickel alloys in sulphuric environment. Influence of friction

    International Nuclear Information System (INIS)

    Ponthiaux, Pierre

    1990-01-01

    This research thesis reports the study of anodic dissolution and passivation of iron-nickel alloys (10, 20 and 31 pc nickel) in a sulphuric environment, with or without friction, by using anodic polarization curves. Without friction, the three alloys have a similar behaviour as pure iron. The analysis reveals different dissolution and passivation mechanisms with pure iron, and highlights the influence of nickel content on corresponding kinetics. The influence of cyclic plane-on-plane friction has been studied for the 31 pc nickel alloy which has an unsteady austenitic structure. Fretting results in some modifications of polarization curves. These modifications are analysed with respect to fretting parameters (relative speed of antagonist surfaces, contact pressure). They reveal the specific influence of the following phenomena: material strain hardening, martensitic transformation induced by strain hardening, partial destruction of adsorbates and/or of the passive film. Modifications of polarization curves give also information on the evolution of friction characteristics with respect to speed (a phenomenon of lubrication by the electrolyte occurs) [fr

  20. Composition pathway in Fe-Cu-Ni alloy during coarsening

    Science.gov (United States)

    Mukherjee, Rajdip; Choudhury, Abhik; Nestler, Britta

    2013-10-01

    In this work the microstructure evolution for a two phase Fe-Cu-Ni ternary alloy is studied in order to understand the kinetic composition paths during coarsening of precipitates. We have employed a quantitative phase-field model utilizing the CALPHAD database to simulate the temporal evolution of a multi-particle system in a two-dimensional domain. The paths for the far-field matrix and for precipitate average compositions obtained from simulation are found to be rectilinear. The trends are compared with the corresponding sharp interface theory, in the context of an additional degree of freedom for determining the interface compositions due to the Gibbs-Thomson effect in a ternary alloy.

  1. Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation

    International Nuclear Information System (INIS)

    Zhan, Wangcheng; Wang, Jinglin; Wang, Haifeng; Zhang, Jinshui; Liu, Xiaofei

    2017-01-01

    Controlling the physical and chemical properties of alloy nanoparticles (NPs) is an important approach to optimize NP catalysis. Unlike other tuning knobs, such as size, shape, and composition, crystal structure has received limited attention and not been well understood for its role in catalysis. This deficiency is mainly due to the difficulty in synthesis and fine-tuning of the NPs’ crystal structure. Here, Exemplifying by AuCu alloy NPs with face centered cubic (fcc) and face centered tetragonal (fct) structure, we demonstrate a remarkable difference in phase segregation and catalytic performance depending on the crystal structure. During the thermal treatment in air, the Cu component in fcc-AuCu alloy NPs segregates more easily onto the alloy surface as compared to that in fct-AuCu alloy NPs. As a result, after annealing at 250 °C in air for 1 h, the fcc- and fct-AuCu alloy NPs are phase transferred into Au/CuO and AuCu/CuO core/shell structures, respectively. More importantly, this variation in heterostructures introduces a significant difference in CO adsorption on two catalysts, leading to a largely enhanced catalytic activity of AuCu/CuO NP catalyst for CO oxidation. Furthermore, the same concept can be extended to other alloy NPs, making it possible to fine-tune NP catalysis for many different chemical reactions.

  2. Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Wangcheng [East China Univ. of Science and Technology, Shanghai (China); Wang, Jinglin [East China Univ. of Science and Technology, Shanghai (China); Wang, Haifeng [East China Univ. of Science and Technology, Shanghai (China); Zhang, Jinshui [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Xiaofei [East China Univ. of Science and Technology, Shanghai (China); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Pengfei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chi, Miaofang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guo, Yanglong [East China Univ. of Science and Technology, Shanghai (China); Guo, Yun [East China Univ. of Science and Technology, Shanghai (China); Lu, Guanzhong [East China Univ. of Science and Technology, Shanghai (China); Sun, Shouheng [Brown Univ., Providence, RI (United States); Dai, Sheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Zhu, Huiyuan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-07

    Controlling the physical and chemical properties of alloy nanoparticles (NPs) is an important approach to optimize NP catalysis. Unlike other tuning knobs, such as size, shape, and composition, crystal structure has received limited attention and not been well understood for its role in catalysis. This deficiency is mainly due to the difficulty in synthesis and fine-tuning of the NPs’ crystal structure. Here, Exemplifying by AuCu alloy NPs with face centered cubic (fcc) and face centered tetragonal (fct) structure, we demonstrate a remarkable difference in phase segregation and catalytic performance depending on the crystal structure. During the thermal treatment in air, the Cu component in fcc-AuCu alloy NPs segregates more easily onto the alloy surface as compared to that in fct-AuCu alloy NPs. As a result, after annealing at 250 °C in air for 1 h, the fcc- and fct-AuCu alloy NPs are phase transferred into Au/CuO and AuCu/CuO core/shell structures, respectively. More importantly, this variation in heterostructures introduces a significant difference in CO adsorption on two catalysts, leading to a largely enhanced catalytic activity of AuCu/CuO NP catalyst for CO oxidation. Furthermore, the same concept can be extended to other alloy NPs, making it possible to fine-tune NP catalysis for many different chemical reactions.

  3. Effect of different ions on the anodic behaviour of alloy 800 chloride solutions at high temperature

    International Nuclear Information System (INIS)

    Lafont, C.J.; Alvarez, M.G.

    1993-01-01

    The anodic behaviour and passivity breakdown of alloy 800 in sodium bicarbonate and sodium phosphate aqueous solutions were studied in the temperature range from 100 degrees C to 280 degrees C by means of electrochemical techniques. The effect of phosphate or bicarbonate additions on the pitting susceptibility and pitting morphology of the alloy in chloride solutions was also examined. Experiments were performed in the following solutions: 0.1M NaHCO 3 , at 100 degrees C, 200 degrees C, 280 degrees C; 0.06M NaH 2 PO 4 + 0.04M Na 2 HPO 4 , at 100 degrees C, 200 degrees C and 280 degrees C, and 0.1M NaCl with different additions of bicarbonate ion (0.02M, 0.05M and 0.1M) and phosphate ion (0.01M, 0.05M and 0.1M) at 100 degrees C and 280 degrees C. The anodic polarization curves of alloy 800 in deaerated 0.1M NaHCO 3 and 0.06M NaH 2 PO 4 + 0.04M Na 2 HPO 4 solutions exhibited a similar shape at all the tested temperatures. No localized or generalized corrosion was detected on the metallic surface after polarization. The results obtained in chloride plus bicarbonate and chloride plus phosphate mixtures showed that the pitting potential of alloy 800 in chloride solutions was increased by the presence of bicarbonate or phosphate ions. In those solutions where the inhibitor concentration in the mixture is equal or higher than the chloride concentration , the behaviour of the alloy is similar to the one observed in the absence of chlorides. Changes in pitting morphology were found in phosphate containing solutions, while the pits found in bicarbonate containing solutions were similar to those formed in pure chloride solutions. (author). 3 refs., 4 figs

  4. Dispersion strengthening of precipitation hardened Al-Cu-Mg alloys prepared by rapid solidification and mechanical alloying

    Science.gov (United States)

    Gilman, P. S.; Sankaran, K. K.

    1988-01-01

    Several Al-4Cu-1Mg-1.5Fe-0.75Ce alloys have been processed from either rapidly solidified or mechanically alloyed powder using various vacuum degassing parameters and consolidation techniques. Strengthening by the fine subgrains, grains, and the dispersoids individually or in combination is more effective when the alloys contain shearable precipitates; consequently, the strength of the alloys is higher in the naturally aged rather than the artificially aged condition. The strengths of the mechanically alloyed variants are greater than those produced from prealloyed powder. Properties and microstructural features of these dispersion strengthened alloys are discussed in regards to their processing histories.

  5. Local structure of disordered Au-Cu and Au-Ag alloys

    International Nuclear Information System (INIS)

    Frenkel, A. I.; Machavariani, V. Sh.; Rubshtein, A.; Rosenberg, Yu.; Voronel, A.; Stern, E. A.

    2000-01-01

    X-ray-absorption fine structure (XAFS) and x-ray-diffraction (XRD) measurements of disordered alloys Au x Cu 1-x and Au 0.5 Ag 0.5 prepared by melt spinning were performed. In the Au 0.5 Ag 0.5 alloy, no significant local deviations of the atoms from the average fcc lattice were detected while in Au x Cu 1-x alloys, significant deviations of atoms from the average fcc lattice were found. Mean-square vibrations of the Cu-Cu distances revealed by the XAFS in Au x Cu 1-x alloys indicate the weakening of contact between Cu atoms in the dilute limit. Our computer simulation for Au x Cu 1-x clusters of 10 5 atoms reproduces the main features of both the XAFS and XRD data

  6. Electronic structure of disordered Cu-Ag alloys

    International Nuclear Information System (INIS)

    Razee, S.S.A.

    1994-08-01

    We present a self-consistent-field Korringa-Kohn-Rostoker coherent potential approximation study of the electronic structure of disordered Cu x Ag 1-x alloys for x=0.0, 0.25, 0.50, 0.75 and 1.0. In particular, we focus on the Fermi surface, density of states, and Bloch spectral density, and study how they evolve as a function of x. We find that, Fermi surface dimensions have a non-linear composition dependence. The disorder-induced smearing of the Fermi surface, as expected, is very high along the direction; both the Cu and Ag Fermi surfaces have a neck in this direction. Whenever possible we have compared our results with the available experimental data. (author). 34 refs, 4 figs

  7. Secondary precipitation in an Al-Mg-Si-Cu alloy

    International Nuclear Information System (INIS)

    Buha, J.; Lumley, R.N.; Crosky, A.G.; Hono, K.

    2007-01-01

    Interruption of a conventional T6 heat treatment at 177 deg. C for the Al-Mg-Si-Cu alloy 6061 after a short period of time (20 min), by inserting a dwell period at a lower temperature (e.g. 65 deg. C), promotes secondary precipitation of Guinier-Preston (GP) zones. As a consequence, a much greater number of precursors to the β'' precipitates are produced so that a finer and denser dispersion of this phase is formed when T6 ageing is resumed. This change in microstructure causes significant and simultaneous improvements in tensile properties and fracture toughness. Secondary precipitation of GP zones occurs through a gradual evolution of a large number of Mg-Si(-Cu)-vacancy co-clusters formed during the initial ageing at 177 deg. C. The precise mechanism of secondary precipitation has been revealed by three-dimensional atom probe microscopy supplemented by transmission electron microscopy and differential scanning calorimetry

  8. Exploring As-Cast PbCaSn-Mg Anodes for Improved Performance in Copper Electrowinning

    Science.gov (United States)

    Yuwono, Jodie A.; Clancy, Marie; Chen, Xiaobo; Birbilis, Nick

    2018-06-01

    Lead calcium tin (PbCaSn) alloys are the common anodes used in copper electrowinning (Cu EW). Given a large amount of energy consumed in Cu EW process, anodes with controlled oxygen evolution reaction (OER) kinetics and a lower OER overpotential are advantageous for reducing the energy consumption. To date, magnesium (Mg) has never been studied as an alloying element for EW anodes. As-cast PbCaSn anodes with the addition of Mg were examined herein, revealing an improved performance compared to that of the industrial standard PbCaSn anode. The alloy performances in the early stages of anode life and passivation were established from electrochemical studies which were designed to simulate industrial Cu EW process. The 24-hour polarization testing revealed that the Mg alloying depolarizes the anode potential up to 80 mV; thus, resulting in a higher Cu EW efficiency. In addition, scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the alteration of the alloy microstructure and the corresponding interfacial reactions contribute to the changes of the anode electrochemical performances. The present study reveals for the first time the potency of Mg alloying in reducing the overpotential of PbCaSn anode.

  9. 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.

  10. Magnetic excitations in CuMn spin-glass alloys

    International Nuclear Information System (INIS)

    Tsunoda, Y.; Kunitomi, N.; Cable, J.W.

    1985-01-01

    Recent neutron scattering measurements have helped to clarify two important features of CuMn spin glasses. Murani and co-workers have studied the dynamical behavior of spin-glass systems and have observed characteristic ferromagnetic spin correlations with a broad distribution of relaxation times and a dynamical freezing process. By means of the polarization analysis technique, Cable and co-workers have observed the coexistence of two types of magnetic short-range order (MSRO): one is a modulated-spin structure, and the other is a ferromagnetic cluster associated with the atomic short-range order (ASRO). These ordered regions produce diffraction maxima which are found at the (1 1/2 +/- delta 0) and the (1 1/2 0) reciprocal lattice points, respectively. Both of these observations seem to be essential for understanding the CuMn spin-glass system. However, the physical relationship of these properties is not yet understood. The authors have studied the inelastic scattering of neutrons around the magnetic diffuse peak positions of a Cu/sub 78.7/Mn/sub 21.3/ single crystal. The spin-glass freezing temperature of a CuMn alloy with this Mn concentration is estimated to be T/sub f/ approx. 90 K. Most of the data were taken by scanning along the [0 1 0] direction from the (1 0 0) to the (1 1 0) reciprocal lattice points

  11. Conical surface textures formed by ion bombarding 2% Be-Cu alloy

    International Nuclear Information System (INIS)

    Panitz, J.K.G.

    1991-01-01

    A homogeneous, micrometer-sized conical surface texture forms on 2% Be-Cu alloy which is bombarded with an argon beam produced by a Kaufman ion source. The dimensions of the features that form depend strongly on argon energy (from 250 to 1500 eV); argon fluence (10 19 to 10 20 ions cm -2 ); and argon flux (0.1 to 1 mA cm -2 ). The texture morphology depends less strongly on the background ambient (Mo versus graphite), earlier alloy heat treatments and the temperature during bombardment (100 o C and 450 o C). As the texture matures with increasing fluence, the number of large features increases at the expense of the number of small features. The observed relationship between texture formation and ion flux suggests that the evolution of these features is not adequately described by theories predicting that the mature conical side-wall angle is related to the angle of the maximum sputtering yield. These textured surfaces can be coated with other metals for a variety of possible applications including pulsed power Li + beam anodes; cold cathode field emission devices; optical absorbers and catalysis supports. (author)

  12. Conical surface textures formed by ion bombarding 2% Be Cu alloy

    International Nuclear Information System (INIS)

    Panitz, J.K.G.

    1990-01-01

    A homogeneous, micrometer-sized conical surface texture forms on 2% Be-Cu alloy which is bombarded with an argon beam produced by a Kaufman ion source. The dimensions of the features that form strongly depend on: (1) argon energy (from 250 to 1500 eV), (2) fluence (10 19 to 10 20 ions/cm 2 ), and (3) flux (0.1 to 1 mA/cm 2 ). The texture morphology depends less strongly on the background ambient (Mo vs graphite), earlier alloy heat treatments and the temperature during bombardment (100 degree C and 450 degree C). As the texture matures with increasing fluence, the number of large features increases at the expense of the number of small features. The observed relationship between texture formation and ion flux suggests that the evolution of these features is not adequately described by theories predicting that the mature conical sidewall angle is related to the angle of the maximum sputtering yield. These textured surfaces can be coated with other metals for a variety of possible applications including: (1) pulsed power Li+ beam anodes, (2) cold cathode field emission devices, (3) optical absorbers and (4) catalysis supports. 18 refs., 5 figs

  13. Improved electrochemical performances of CuO nanotube array prepared via electrodeposition as anode for lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-10-15

    Graphical abstract: CuO nanotube array electrodes prepared by electrodeposition method exhibit an excellent lithium ion storage ability as anode of Li-ion battery. - Highlights: • CuO nanotube arrays are synthesized by an electrodeposition method. • CuO nanotube shows a high-rate performance. • CuO nanotube shows an excellent cycling performance. - Abstract: We report a facile strategy to prepared CuO nanotube arrays directly grown on Cu plate through the electrodeposition method. The as-prepared CuO nanotubes show a quasi-cylinder nanostructure with internal diameters of ca. ∼100 nm, external diameters of ca. ∼120 nm, and average length of ∼3 μm. As an anode for lithium ion batteries, the electrochemical properties of the CuO nanotube arrays are investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests. Due to the unique nanotube nanostructure, the as-prepared CuO electrodes exhibit good rate performance (550 mAh g{sup −1} at 0.1 C and 464 mAh g{sup −1} at 1 C) and cycling performance (581 mAh g{sup −1} at 0.1 C and 538 mAh g{sup −1} at 0.5 C)

  14. Structure and mechanical properties of nanostructured Al-0.3%Cu alloy

    DEFF Research Database (Denmark)

    Wakeel, Aneela; Huang, Tianlin; Wu, Guilin

    2014-01-01

    An Al-0.3%Cu alloy has been produced using extremely high purity (99.9996%) Al and OFHC Cu.The alloy was cold rolled to 98% thickness reduction, forming a stable lamellar structure that has a lamellar boundary spacing of about 200nm and a tensile strength of 225MPa. During recovery annealing at t...

  15. Alloy development for the enhanced stability of Ω precipitates in Al-Cu-Mg-Ag alloys

    Science.gov (United States)

    Gable, B. M.; Shiflet, G. J.; Starke, E. A.

    2006-04-01

    The coarsening resistance and thermal stability of several Ω plate-dominated microstructures were controlled through altering the chemistry and thermomechanical processing of various Al-Cu-Mg-Ag alloys. Quantitative comparisons of Ω nucleation density, particle size, and thermal stability were used to illustrate the effects of alloy composition and processing conditions. The long-term stability of Ω plates was found to coincide with relatively high levels of silver and moderate magnesium additions, with the latter limiting the competition for solute with S-phase precipitation. This analysis revealed that certain microstructures initially dominated by Ω precipitation were found to remain stable through long-term isothermal and double-aging heat treatments, which represents significant improvement over the previous generation of Al-Cu-Mg-Ag alloys, in which Ω plates dissolved sacrificially after long aging times. The quantitative precipitate data, in conjunction with a thermodynamic database for the aluminum-rich corner of the Al-Cu-Mg-Ag quaternary system, were used to estimate the chemistry of the α/Ω-interphase boundary. These calculations suggest that silver is the limiting species at the α/Ω interfacial layer and that Ω plates form with varying interfacial chemistries during the early stages of artificial aging, which is directly related to the overall stability of certain plates.

  16. The effects of Cu addition on the microstructure and thermal stability of an Al-Mg-Si alloy

    International Nuclear Information System (INIS)

    Man, Jin; Jing, Li; Jie, Shao Guang

    2007-01-01

    The effects of Cu addition on the microstructure and thermal stability of 6082 Al-Mg-Si alloys were investigated. The results show the Q' precipitates are formed when aged at 170 o C for 4 h in 6082 alloy with 0.6% Cu addition. The hardness value of the alloy with 0.6% Cu is always distinctly higher than that of the alloy without Cu during isothermal treatment at 250 o C. Based on the TEM and three-dimensional atom probe (3DAP) results, the thermal stability of the 6082 alloys with Cu addition is discussed with respect to the distribution of Cu

  17. Anode behaviors of aluminum antimony synthesized by mechanical alloying for lithium secondary battery

    International Nuclear Information System (INIS)

    Honda, H.; Sakaguchi, H.; Fukuda, Y.; Esaka, T.

    2003-01-01

    AlSb was synthesized as an anode active material for lithium secondary battery using mechanical alloying (MA). Electrochemical performance was examined on the electrodes of AlSb synthesized with different MA time. The first charge (lithium-insertion) capacity of the AlSb electrodes decreased with increasing the MA time. The discharge capacity on repeating charge-discharge cycle, however, did not show the same dependence. The electrode, consisting of the 20 h MA sample exhibited the longest charge-discharge life cycle, suggesting that there is the optimum degree of internal energy derived from the strain and/or the amorphization due to mechanical alloying. These results were evaluated using ex situ X-ray diffraction and differential scanning calorimetry

  18. Desorption dynamics of deuterium in CuCrZr alloy

    Science.gov (United States)

    Thi Nguyen, Lan Anh; Lee, Sanghwa; Noh, S. J.; Lee, S. K.; Park, M. C.; Shu, Wataru; Pitcher, Spencer; Torcy, David; Guillermain, David; Kim, Jaeyong

    2017-12-01

    Desorption behavior of deuterium (D2) in CuCrZr alloy was investigated considering sample thickness, loading and baking temperature of deuterium followed by the ITER scopes. Cylindrical specimens of 1, 3, 5 mm thick with 4 mm diameter were exposed to deuterium at a pressure of 25 bar at 120, 240 and 350 °C for 24 h, then baked at 800 °C in a vacuum chamber maintained at a pressure lower than 10-7 Torr. Deuterium desorption characteristics such as desorption rate and amount of deuterium in the sample were estimated by analyzing the desorption peaks monitored with a residual gas analyzer (RGA), and the trapping energy of deuterium was calculated using thermal desorption spectroscopy (TDS). Secondary ion mass spectroscopy (SIMS) results showed that deuterium atoms embedded in the sample at a depth of less than 15 μm and desorbed as low as 400 °C. All absorbed deuterium atoms in the specimen were completely retrieved by dynamic pumping at 800 °C in 15 min. The desorption rate of deuterium per unit area was inversely proportional to the increment of the thickness of the sample, and was proportional to the loading temperature. Based on the assumption that a uniform distribution of interstitial sites for deuterium follows the Femi-Dirac statistics, the result of TDS demonstrated that the CuCrZr alloy has two types of trapping energies, which were estimated to be 62 and 79 kJ/mol.

  19. Structural investigation of Fe(Cu)ZrB amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Duhaj, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Matko, I. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Svec, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Sitek, J. [Department of Nuclear Physics and Technology, Slovak Technical University, 81219 Bratislava (Slovakia); Janickovic, D. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav

    1996-07-01

    The crystallization process in Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} alloys. In both alloys the first crystallization begins with the formation of nanocrystalline {alpha}-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of {alpha}-Fe and dispersed Fe{sub 23}Zr{sub 6} phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  20. Structural investigation of Fe(Cu)ZrB amorphous alloy

    International Nuclear Information System (INIS)

    Duhaj, P.; Janickovic, D.

    1996-01-01

    The crystallization process in Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 alloys. In both alloys the first crystallization begins with the formation of nanocrystalline α-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of α-Fe and dispersed Fe 23 Zr 6 phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  1. Microstructural characterization of alloys of the quasibinary Cu-NiBe system

    Energy Technology Data Exchange (ETDEWEB)

    Spaic, S.; Markoli, B. [Univ. of Ljubljana, Faculty of Natural Science and Engineering, Ljubljana (Slovenia)

    2003-08-01

    Alloys of the quasibinary section Cu-NiBe were experimentally investigated with differential thermal analysis, optical microscopy, electron microanalysis, transmission electron microscopy and X-ray diffraction. The construction of the quasibinary Cu-NiBe phase diagram was made based on the experimental results. The constitution of alloys of the whole section was studied along with the investigation of the microstructure and crystallographic relationship of the NiBe phase in aged alloys from the Cu-rich corner of the Cu-NiBe system. (orig.)

  2. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    Directory of Open Access Journals (Sweden)

    Andrea Školáková

    2017-11-01

    Full Text Available In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  3. Wetting Behavior of Ternary Au-Ge-X (X = Sb, Sn) Alloys on Cu and Ni

    Science.gov (United States)

    Jin, S.; Valenza, F.; Novakovic, R.; Leinenbach, C.

    2013-06-01

    Au-Ge-based alloys are potential substitutes for Pb-rich solders currently used for high-temperature applications. In the present work, the wetting behavior of two Au-Ge-X (X = Sb, Sn) ternary alloys, i.e., Au-15Ge-17Sb and Au-13.7 Ge-15.3Sn (at.%), in contact with Cu and Ni substrates has been investigated. Au-13.7Ge-15.3Sn alloy showed complete wetting on both Cu and Ni substrates. Total spreading of Au-15Ge-17Sb alloy on Cu was also observed, while the final contact angle of this alloy on Ni was about 29°. Pronounced dissolution of Cu substrates into the solder alloys investigated was detected, while the formation of Ni-Ge intermetallic compounds at the interface of both solder/Ni systems suppressed the dissolution of Ni into the solder.

  4. Age hardening and creep resistance of cast Al–Cu alloy modified by praseodymium

    International Nuclear Information System (INIS)

    Bai, Zhihao; Qiu, Feng; Wu, Xiaoxue; Liu, Yingying; Jiang, Qichuan

    2013-01-01

    The effects of praseodymium on age hardening behavior and creep resistance of cast Al–Cu alloy were investigated. The results indicated that praseodymium facilitated the formation of the θ′ precipitates during the age process and improved the hardness of the Al–Cu alloy. Besides, praseodymium resulted in the formation of the Al 11 Pr 3 phase in the grain boundaries and among the dendrites of the modified alloy. Because of the good thermal stability of Al 11 Pr 3 phase, it inhibits grain boundary migration and dislocation movement during the creep process, which contributes to the improvement in the creep resistance of the modified alloy at elevated temperatures. - Highlights: • Pr addition enhances the hardness and creep resistance of the Al–Cu alloy. • Pr addition facilitates the formation of the θ′ precipitates. • Pr addition results in the formation of the Al11Pr3 phase in the Al–Cu alloy

  5. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability.

    Science.gov (United States)

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-11-05

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  6. Sn buffered by shape memory effect of NiTi alloys as high-performance anodes for lithium ion batteries

    International Nuclear Information System (INIS)

    Hu Renzong; Zhu Min; Wang Hui; Liu Jiangwen; Liuzhang Ouyang; Zou Jin

    2012-01-01

    By applying the shape memory effect of the NiTi alloys to buffer the Sn anodes, we demonstrate a simple approach to overcome a long-standing challenge of Sn anode in the applications of Li-ion batteries – the capacity decay. By supporting the Sn anodes with NiTi shape memory alloys, the large volume change of Sn anodes due to lithiation and delithiation can be effectively accommodated, based on the stress-induced martensitic transformation and superelastic recovery of the NiTi matrix respectively, which leads to a decrease in the internal stress and closing of cracks in Sn anodes. Accordingly, stable cycleability (630 mA h g −1 after 100 cycles at 0.7C) and excellent high-rate capabilities (478 mA h g −1 at 6.7C) were attained with the NiTi/Sn/NiTi film electrode. These shape memory alloys can also combine with other high-capacity metallic anodes, such as Si, Sb, Al, and improve their cycle performance.

  7. Time evolution of morphology in mechanically alloyed Fe-Cu

    KAUST Repository

    Wille, Catharina Gabriele

    2011-05-01

    Being widely accessible as well as already utilised in many applications, Fe-Cu acts as an ideal binary model alloy to elaborate the enforced nonequilibrium enhanced solubility in such a solution system that shows a limited regime of miscibility and characterised by a large positive heat of mixing. In addition to the detailed analysis of ball milled Fe-Cu powders by means of Atom Probe Tomography (APT), site specific structural analysis has been performed in this study using Transmission Electron Microscopy (TEM).In this contribution results on powders with low Cu concentrations (2.5-10 at%) are presented. Combining a ductile element (Cu, fcc) and a brittle one (Fe, bcc), striking differences in morphology were expected and found on all length-scales, depending on the mixing ratio of the two elements. However, not only could the atomic mixing of Fe and Cu be evaluated, but also the distribution of impurities, mostly stemming from the fabrication procedure. The combination of APT and TEM enables a correlation between the structural evolution and the chemical mixing during the milling process. For the first time, a clear distinction can be drawn between the morphological evolution at the surface and in the interior of the powder particles. This became possible owing to the site specific sample preparation of TEM lamellae by Focussed Ion Beam (FIB). Surprisingly, the texture arising from the ball milling process can directly be related to the classical rolling texture of cold rolled Fe. In addition, full homogeneity can be achieved even on the nano-scale for this material as shown by APT, resulting in an extended miscibility region in comparison to the equilibrium phase diagram. Grain sizes were determined by means of XRD and TEM. The strain corrected XRD results are in very good agreement with the values derived by TEM, both confirming a truly nanocrystalline structure. © 2011 Elsevier B.V.

  8. Effect of Silica Sol on Boric-sulfuric Acid Anodic Oxidation of LY12CZ Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    LIU Hui-cong

    2016-07-01

    Full Text Available Aluminum alloy anodizing coatings were prepared for LY12CZ in the boric-sulfuric acid solution (45g/L sulfuric acid,8g/L boric acid with the addition of 10%,20%,30% (volume fractionsilica sol,with the gradient voltage of 15V. The current and voltage transients of the anodizing process were collected by data collection instrument. The surface morphologies,microstructure and chemical composition of the anodic coatings were characterized by scanning electron microscopy (SEM. The corrosion resistance was examined by neutral salt spray,electrochemical impedance spectroscopy (EIS test and titrating test. The results show that the different concentration of silica sol addition can influence the forming and dissolution of anodizing coatings,improve the compactness smoothness and corrosion resistance during the anodizing process in the boric-sulfuric acid solution.

  9. Influence of Mn on the tensile properties of SSM-HPDC Al-Cu-Mg-Ag alloy A201

    CSIR Research Space (South Africa)

    Müller, H

    2011-03-01

    Full Text Available A201 aluminium alloy is a high strength casting alloy with a nominal composition of Al-4.6Cu-0.3Mg-0.6Ag. It is strengthened by the O(Al2Cu) phase and the ’(Al2Cu) phase during heat treatment. Further strengthening of this alloy system can...

  10. Anodic behavior of mechanically alloyed Cu–Ni–Fe and Cu–Ni–Fe–O electrodes for aluminum electrolysis in low-temperature KF-AlF3 electrolyte

    International Nuclear Information System (INIS)

    Goupil, G.; Helle, S.; Davis, B.; Guay, D.; Roué, L.

    2013-01-01

    A comparative study on the anodic behavior of Cu 65 Ni 20 Fe 15 and (Cu 65 Ni 20 Fe 15 ) 98.6 O 1.4 materials during the electrolysis of aluminum was conducted. Both materials were prepared in powder form by ball milling and subsequently consolidated to form dense pellets that were used as anodes. The electrochemical characterization was performed at 700 °C in a potassium cryolite-based electrolyte, and the composition-morphology of the oxide scales formed on both anodes were determined by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction measurements. On Cu 65 Ni 20 Fe 15 , a thick (170 μm) and porous oxide scale is formed after 15 min of electrolysis that readily dissolves (or spalls) before a denser oxide layer is formed after a longer electrolysis time (1 and 5 h). In comparison, a thin (2 μm) and dense oxide layer mainly composed of NiFe 2 O 4 is observed on a (Cu 65 Ni 20 Fe 15 ) 98.6 O 1.4 electrode after 15 min of electrolysis. The thickness of this oxide layer increases to 10 and 30 μm after 1 h and 5 h of electrolysis. However, the outward diffusion of Cu to form CuO x at the surface of the electrode is not totally hampered by the presence of NiFe 2 O 4 and a porous Cu-depleted region is formed at the oxide/alloy interface. As a result, electrolyte penetration occurs in the scale, which favors the progressive formation of an iron fluoride layer at the oxide/alloy interface

  11. Influence of annealing and deformation on optical properties of ultra precision diamond turned and anodized 6060 aluminium alloy

    DEFF Research Database (Denmark)

    Tabrizian-Ghalehno, Naja; Hansen, Hans Nørgaard; Hansen, P.E.

    2010-01-01

    Influence of cold forging, and subsequent heat treatment and diamond turning on optical quality of anodized film on 6060 (AlMgSi) alloy was investigated and compared with microstructural changes. Heat treatment of the samples was carried out either prior to forging, post-forging, or both. The sur......Influence of cold forging, and subsequent heat treatment and diamond turning on optical quality of anodized film on 6060 (AlMgSi) alloy was investigated and compared with microstructural changes. Heat treatment of the samples was carried out either prior to forging, post-forging, or both...

  12. Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

    KAUST Repository

    Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Lai, Zhiping; Li, Lain-Jong; Huang, Kuo-Wei

    2017-01-01

    A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH

  13. Hierarchical shell/core CuO nanowire/carbon fiber composites as binder-free anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yuan, Wei; Luo, Jian; Pan, Baoyou; Qiu, Zhiqiang; Huang, Shimin; Tang, Yong

    2017-01-01

    Highlights: •The composite anode is composed of CuO nanowire shell and carbon fiber core. •The composite anode avoids completely the use of binders. •Synergistic effect of carbon fibers and CuO nanowires enhances performance. •Carbon fibers improve electrical conductivity and buffer volume change. •CuO nanowires shorten diffusion length and alleviate structural strain. -- Abstract: Developing high-performance electrode structures is of great importance for advanced lithium-ion batteries. This study reports an efficient method to fabricate hierarchical shell/core CuO nanowire/carbon fiber composites via electroless plating and thermal oxidation processes. With this method, a binder-free CuO nanowire/carbon fiber shell/core hierarchical network composite anode for lithium-ion batteries is successfully fabricated. The morphology and chemical composition of the anode are characterized, and the electrochemical performance of the anode is investigated by standard electrochemical tests. Owing to the superior properties of carbon fibers and the morphological advantages of CuO nanowires, this composite anode still retains an excellent reversible capacity of 598.2 mAh g −1 with a capacity retention rate above 86%, even after 50 cycles, which is much higher than the CuO anode without carbon fibers. Compared to the typical CuO/C electrode systems, the novel binder-free anode yields a performance close to that of the typical core/shell electrode systems and a much higher reversible capacity and capacity retention than the similar shell/core patterns as well as the anodes with binders. It is believed that this novel anode will pave the way to the development of binder-free anodes in response to the increasing demands for high-power energy storage.

  14. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg) alloys

    OpenAIRE

    M. Kaczorowski; A. Krzyńska

    2007-01-01

    The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg) type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening ...

  15. Misoriented dislocation substructures and the fracture of polycrystalline Cu-Al alloys

    Science.gov (United States)

    Koneva, N. A.; Trishkina, L. I.; Cherkasova, T. V.; Kozlov, E. V.

    2016-10-01

    The evolution of the dislocation substructure in polycrystalline Cu-Al alloys with various grain sizes is studied during deformation to failure. A relation between the fracture of the alloys and the forming misorientation dislocation substructures is revealed. Microcracks in the alloy are found to form along grain boundaries and the boundaries of misoriented dislocation cells and microtwins.

  16. Ag-Pd-Cu alloy inserted transparent indium tin oxide electrodes for organic solar cells

    International Nuclear Information System (INIS)

    Kim, Hyo-Joong; Seo, Ki-Won; Kim, Han-Ki; Noh, Yong-Jin; Na, Seok-In

    2014-01-01

    The authors report on the characteristics of Ag-Pd-Cu (APC) alloy-inserted indium tin oxide (ITO) films sputtered on a glass substrate at room temperature for application as transparent anodes in organic solar cells (OSCs). The effect of the APC interlayer thickness on the electrical, optical, structural, and morphological properties of the ITO/APC/ITO multilayer were investigated and compared to those of ITO/Ag/ITO multilayer electrodes. At the optimized APC thickness of 8 nm, the ITO/APC/ITO multilayer exhibited a resistivity of 8.55 × 10 −5 Ω cm, an optical transmittance of 82.63%, and a figure-of-merit value of 13.54 × 10 −3 Ω −1 , comparable to those of the ITO/Ag/ITO multilayer. Unlike the ITO/Ag/ITO multilayer, agglomeration of the metal interlayer was effectively relieved with APC interlayer due to existence of Pd and Cu elements in the thin region of the APC interlayer. The OSCs fabricated on the ITO/APC/ITO multilayer showed higher power conversion efficiency than that of OSCs prepared on the ITO/Ag/ITO multilayer below 10 nm due to the flatness of the APC layer. The improved performance of the OSCs with ITO/APC/ITO multilayer electrodes indicates that the APC alloy interlayer prevents the agglomeration of the Ag-based metal interlayer and can decrease the thickness of the metal interlayer in the oxide-metal-oxide multilayer of high-performance OSCs

  17. Selective anodic dissolution of cerium from aluminium alloys under potentiostatic conditions

    International Nuclear Information System (INIS)

    Gol'dshtejn, S.L.; Raspopin, S.P.; Seleznev, V.D.; Tunin, A.V.; Fedorov, V.A.

    1975-01-01

    A study was made of selective anodic dissolution of aluminum alloys containing cerium in concentrations from 0.5 to 10% by mass. The electropurification was carried out with the aid of a potentiostatic setup at 700 deg C in atmosphere of purified argon. Liquid aluminum served as the cathode, with chlorine half-cell as reference electrode and the melt of equimolar KCl-NaCl mixture as the electrolyte. The ''current-time'' plots are presented for selective ionization of cerium from aluminum alloys at preset potential values on the installation. For PHIsub(preset)=-2.04 v the current of potentiostatic electrolysis fades out to that of the supporting electrolyte, and the process itself proceeds at a rate that provides maximal extraction of cerium from the alloy (csub9finite)approximately equal to 0.002% by mass) at minimal ionization of the metalsolvent (Δ Msub(Al)approximately equal to 0.2). Alloys containing not less then 1% by mass of Ce exhibit a characteristic abrupt change of the attenuation coefficient apparently owing to nonlinear dependence of unbalance (ΔE) of signals at the input of the potentiostat. The ''ΔE-c'' function for Al alloy containing 0.5% by mass of Ce can be approximated by linear function. In this case the current of potentiostatic electrolysis approaches the value of the limiting diffusion current. To obtain the relationship between the magnitude of the limiting current of Ce ionization and the initial composition of the dissolving alloy, measurements were made under potentiodynamic conditions at a scanning rate of approximately equal to 500 mv/min. The results indicate that isub(intermediate) is directly proportional to csub(initial). It was shown that under the conditions employed, practically complete (csub(finite)<=0.004% by mass) extraction of the electronegative component is possible without noticeable ionization of the metal-solvent

  18. Minor-alloyed Cu-Ni-Si alloys with high hardness and electric conductivity designed by a cluster formula approach

    Directory of Open Access Journals (Sweden)

    Dongmei Li

    2017-08-01

    Full Text Available Cu-Ni-Si alloys are widely used due to their good electrical conductivities in combination with high strength and hardness. In the present work, minor-alloying with M = (Cr, Fe, Mo, Zr was conducted for the objective of further improving their hardness while maintaining their conductivity level. A cluster-plus-glue-atom model was introduced to design the compositions of M-alloyed Cu-Ni-Si alloys, in which an ideal composition formula [(Ni,Si,M-Cu12]Cu3 (molar proportion was proposed. To guarantee the complete precipitation of solute elements in fine δ-Ni2Si precipitates, the atomic ratio of (Ni,M/Si was set as 2/1. Thus the designed alloy series of Cu93.75(Ni/Zr3.75Si2.08(Cr/Fe/Mo0.42 (at% were arc-melted into ingots under argon atmosphere, and solid-solutioned at 950 °C for 1 h plus water quenching and then aged at 450 °C for different hours. The experimental results showed that these designed alloys exhibit high hardness (HV > 1.7 GPa and good electrical conductivities (≥ 35% IACS. Specifically, the quinary Cu93.75Ni3.54Si2.08(Cr/Fe0.42Zr0.21 alloys (Cu-3.32Ni-0.93Si-0.37(Cr/Fe−0.30Zr wt% possess both a high hardness with HV = 2.5–2.7 GPa, comparable to the high-strength KLFA85 alloy (Cu-3.2Ni-0.7Si-1.1Zn wt%, HV = 2.548 GPa, and a good electrical conductivity (35–36% IACS.

  19. 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

  20. Evaluation of shot peening on the fatigue strength of anodized Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    Costa Midori Yoshikawa Pitanga

    2006-01-01

    Full Text Available The increasingly design requirements for modern engineering applications resulted in the development of new materials with improved mechanical properties. Low density, combined with excellent weight/strength ratio as well as corrosion resistance, make the titanium attractive for application in landing gears. Fatigue control is a fundamental parameter to be considered in the development of mechanical components. The aim of this research is to analyze the fatigue behavior of anodized Ti-6Al-4V alloy and the influence of shot peening pre treatment on the experimental data. Axial fatigue tests (R = 0.1 were performed, and a significant reduction in the fatigue strength of anodized Ti-6Al-4V was observed. The shot peening superficial treatment, which objective is to create a compressive residual stress field in the surface layers, showed efficiency to increase the fatigue life of anodized material. Experimental data were represented by S-N curves. Scanning electron microscopy technique (SEM was used to observe crack origin sites.

  1. Devitrification behavior and glass-forming ability of Cu-Zr-Ag alloys

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, Dmitri V.; Xie, Guoqiang; Zhang, Wei; Inoue, Akihisa

    2007-01-01

    This paper presents an influence of Ag addition on the glass-forming ability and devitrification behavior of Cu-Zr glassy alloys on heating. The crystallization kinetics and structure changes in Cu 45 Zr 45 Ag 10 and Cu 35 Zr 45 Ag 20 glassy alloys on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Based on the results obtained one can assume that the improvement of the glass-forming ability of the Cu-Zr alloys by the addition of Ag is connected with a particular crystallization mechanism and a higher reduced glass-transition temperature of the Cu 45 Zr 45 Ag 10 ternary alloy compared to the binary Cu 55 Zr 45 counterpart. As observed in the present work crystallization of the Cu-Zr-Ag alloys is found to cause embitterment of the samples and should be avoided as these alloys are considered to be used as structural materials. The Cu 35 Zr 45 Ag 20 alloy shows possible submicron-scale phase separation upon annealing

  2. Copper-Silver Alloy Depositions Using Thermionic Vacuum ARC (TVA)

    International Nuclear Information System (INIS)

    Akan, T.

    2004-01-01

    TVA is a plasma source generating pure metal vapor plasma and consists of a heated cathode emitting thermo electrons and an anode containing material to be evaporated. We used Cu and Ag pieces as anode materials and produced their alloys by electron bombarding. Cu-Ag alloys in various mass ratios were prepared by using the TVA and the TVA discharges were generated in the vapors of these alloys. The volt-ampere characteristics of the TVA discharges generated in the vapors of these alloys were investigated with respect to the ratio of Ag in the Cu-Ag alloy. Cu-Ag alloy thin films with various mass ratios were deposited onto the glass substrates by using their TVA discharges. The ratios of Cu and Ag in the thin Cu-Ag alloy films were found using scanning electron microscope-energy dispersive xray (SEM-EDX) microanalyses

  3. Synthesis and electrochemical characteristics of Sn-Sb-Ni alloy composite anode for Li-ion rechargeable batteries

    International Nuclear Information System (INIS)

    Guo Hong; Zhao Hailei; Jia Xidi; Qiu Weihua; Cui Fenge

    2007-01-01

    Micro-scaled Sn-Sb-Ni alloy composite was synthesized from oxides of Sn, Sb and Ni via carbothermal reduction. The phase composition and electrochemical properties of the Sn-Sb-Ni alloy composite anode material were studied. The prepared alloy composite electrode exhibits a high specific capacity and a good cycling stability. The lithiation capacity was 530 mAh g -1 in the first cycle and maintained at 370-380 mAh g -1 in the following cycles. The good electrochemical performance may be attributed to its relatively large particle size and multi-phase characteristics. The former reason leads to the lower surface impurity and thus the lower initial capacity loss, while the latter results in a stepwise lithiation/delithiation behavior and a smooth volume change of electrode in cycles. The Sn-Sb-Ni alloy composite material shows a good candidate anode material for the rechargeable lithium ion batteries

  4. Formation of Al70Cu20Fe10 icosahedral quasicrystal by mechanically alloyed method

    International Nuclear Information System (INIS)

    Yin Shilong; Bian Qing; Qian Liying; Zhang Aimei

    2007-01-01

    The structural evolutions of the mechanically alloyed ternary Al 70 Cu 20 Fe 10 powders with the milling time and the annealing treatment have been studied by X-ray diffraction (XRD), transmission electronic microscopy (TEM) and X-ray absorption fine-structure spectroscopy (XAFS) techniques. Results show that an Al 2 Cu compound forms with short-time milling, while a Cu 9 Al 4 compound forms with long-time milling. Fe can react with Al-Cu alloy by annealing treatment. Al 7 Cu 2 Fe compound with tetragonal structure or Al (Cu, Fe) solid solution with cubic structure may form at lower temperature, while a quasicrystal phase of Al 65 Cu 20 Fe 15 alloy may form at higher temperature

  5. Correlation between the resistivity and the atomic clusters in liquid Cu-Sn alloys

    Science.gov (United States)

    Jia, Peng; Zhang, Jinyang; Hu, Xun; Li, Cancan; Zhao, Degang; Teng, XinYing; Yang, Cheng

    2018-05-01

    The liquid structure of CuxSn100-x (x = 0, 10, 20, 33, 40, 50, 60, 75, 80 and 100) alloys with atom percentage were investigated with resistivity and viscosity methods. It can be found from the resistivity data that the liquid Cu75Sn25 and Cu80Sn20 alloys had a negative temperature coefficient of resistivity (TCR), and liquid Cu75Sn25 alloy had a minimum value of -9.24 μΩ cm K-1. While the rest of liquid Cu-Sn alloys had a positive TCR. The results indicated that the Cu75Sn25 atomic clusters existed in Cu-Sn alloys. In addition, the method of calculating the percentage of Cu75Sn25 atomic clusters was established on the basis of resistivity theory and the law of conservation of mass. The Cu75Sn25 alloy had a maximum volume of the atomic clusters and a highest activation energy. The results further proved the existence of Cu75Sn25 atomic clusters. Furthermore, the correlation between the liquid structure and the resistivity was established. These results provide a useful reference for the investigation of liquid structure via the sensitive physical properties to the liquid structure.

  6. Non-sparking anodization process of AZ91D magnesium alloy under low AC voltage

    International Nuclear Information System (INIS)

    Li, Weiping; Li, Wen; Zhu, Liqun; Liu, Huicong; Wang, Xiaofang

    2013-01-01

    Highlights: ► Four different processes appear on magnesium alloys with applied voltage increase. ► Non-sparking film formation process occurred in the range of 6–10 V AC. ► The film was composed of Mg 2 SiO 4 with a stable growth rate in 30 min. ► Film growth was a balance of electrochemical dissolution and chemical deposition. -- Abstract: Anodization is widely recognized as one of the most important surface treatments for magnesium alloys. However, since high voltage oxidation films are limited in some applications due to porosity and brittleness, it is worthwhile to explore the non-sparking oxidizing process. In this work, AZ91D was electrochemically anodized at different AC voltages in an electrolyte containing 120 g/L NaOH and 80 g/L Na 2 SiO 3 ·9H 2 O. The effects of voltage on the surface morphology, composition and reaction process, especially the non-sparking discharge anodic film formation process, were investigated. The results showed that four different processes would appear according to the applied voltage variation from 6 V to 40 V, and that the non-sparking film formation process occurred in the range of 6–10 V. The film formed on the AZ91D surface under 10 V AC was mainly composed of Mg 2 SiO 4 with a lamellar structure. The horizontal and vertical expansion of the lamellar structure resulted in the formation of a multi-layered structure with a stable, linear growth rate for 30 min. The non-sparking film formation process can be considered to be the result of a balance of electrochemical dissolution and chemical deposition reaction

  7. Non-sparking anodization process of AZ91D magnesium alloy under low AC voltage

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weiping, E-mail: liweiping@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Wen [AVIC Beijing Aeronautical Manufacturing Technology Research Institue, Beijing 100024 (China); Zhu, Liqun; Liu, Huicong; Wang, Xiaofang [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2013-04-20

    Highlights: ► Four different processes appear on magnesium alloys with applied voltage increase. ► Non-sparking film formation process occurred in the range of 6–10 V AC. ► The film was composed of Mg{sub 2}SiO{sub 4} with a stable growth rate in 30 min. ► Film growth was a balance of electrochemical dissolution and chemical deposition. -- Abstract: Anodization is widely recognized as one of the most important surface treatments for magnesium alloys. However, since high voltage oxidation films are limited in some applications due to porosity and brittleness, it is worthwhile to explore the non-sparking oxidizing process. In this work, AZ91D was electrochemically anodized at different AC voltages in an electrolyte containing 120 g/L NaOH and 80 g/L Na{sub 2}SiO{sub 3}·9H{sub 2}O. The effects of voltage on the surface morphology, composition and reaction process, especially the non-sparking discharge anodic film formation process, were investigated. The results showed that four different processes would appear according to the applied voltage variation from 6 V to 40 V, and that the non-sparking film formation process occurred in the range of 6–10 V. The film formed on the AZ91D surface under 10 V AC was mainly composed of Mg{sub 2}SiO{sub 4} with a lamellar structure. The horizontal and vertical expansion of the lamellar structure resulted in the formation of a multi-layered structure with a stable, linear growth rate for 30 min. The non-sparking film formation process can be considered to be the result of a balance of electrochemical dissolution and chemical deposition reaction.

  8. Core-shell Si/Cu nanocomposites synthesized by self-limiting surface reaction as anodes for lithium ion batteries

    Science.gov (United States)

    Xu, Kaiqi; Zhang, Zhizhen; Su, Wei; Huang, Xuejie

    Core-shell Si/Cu nanocomposites were synthesized via a flexible self-limiting surface reaction without extra reductant for the first time. The nano Si was uniformly coated with Cu nanoparticles with a diameter of 5-10nm, which can enhance the electronic conductivity of the nanocomposites and buffer the huge volume change during charge/discharge owing to its high ductility. Benefited from the unique structure, the Si/Cu nanocomposites exhibited a good electrochemical performance as anodes for lithium ion batteries, which exhibited a capacity retention of 656mAh/g after 50 cycles and a coulombic efficiency of more than 99%.

  9. The Influence of Alloy Composition on the Hot Tear Susceptibility of the Al-Zn-Mg-Cu Alloy System

    International Nuclear Information System (INIS)

    Kim, Jee-Hun; Jo, Jae-Sub; Sim, Woo-Jeong; Im, Hang-Joon

    2012-01-01

    Hot tearing was the most significant casting defect when the castability evaluation of the Al- Zn-Mg-Cu alloy system was conducted. It was related to the solidification range of the alloy. Therefore, the hot tear susceptibility of the AA7075 alloy, whose solidification range is the widest, was evaluated. The hot tear susceptibility was evaluated by using a mold for a hot tearing test designed to create the condition for the occurrence of hot tear in 8 steps. According to the tearing location and shape, a hot tear susceptibility index (HTS) score was measured. The solidification range of each alloy and hot tear susceptibility was compared and thereafter the microstructure of a near tear defect was observed. As a result, the HTS of the AA7075 alloy was found to be 67. Also, the HTS in relation to a change in Zn, Mg, Cu composition showed a difference of about 6-11% compared to the AA7075 alloy.

  10. Minor-Cu doped soft magnetic Fe-based FeCoBCSiCu amorphous alloys with high saturation magnetization

    Science.gov (United States)

    Li, Yanhui; Wang, Zhenmin; Zhang, Wei

    2018-05-01

    The effects of Cu alloying on the amorphous-forming ability (AFA) and magnetic properties of the P-free Fe81Co5B11C2Si1 amorphous alloy were investigated. Addition of ≤ 1.0 at.% Cu enhances the AFA of the base alloy without significant deterioration of the soft magnetic properties. The Fe80.5Co5B11C2Si1Cu0.5 alloy with the largest critical thickness for amorphous formation of ˜35 μm possesses a high saturation magnetization (Bs) of ˜1.78 T, low coercivity of ˜14.6 A/m, and good bending ductility upon annealing in a wide temperature range of 513-553 K with maintaining the amorphous state. The fabrication of the new high-Fe-content Fe-Co-B-C-Si-Cu amorphous alloys by minor doping of Cu gives a guideline to developing high Bs amorphous alloys with excellent AFA.

  11. The physical metallurgy of mechanically-alloyed, dispersion-strengthened Al-Li-Mg and Al-Li-Cu alloys

    Science.gov (United States)

    Gilman, P. S.

    1984-01-01

    Powder processing of Al-Li-Mg and Al-Li-Cu alloys by mechanical alloying (MA) is described, with a discussion of physical and mechanical properties of early experimental alloys of these compositions. The experimental samples were mechanically alloyed in a Szegvari attritor, extruded at 343 and 427 C, and some were solution-treated at 520 and 566 C and naturally, as well as artificially, aged at 170, 190, and 210 C for times of up to 1000 hours. All alloys exhibited maximum hardness after being aged at 170 C; lower hardness corresponds to the solution treatment at 566 C than to that at 520 C. A comparison with ingot metallurgy alloys of the same composition shows the MA material to be stronger and more ductile. It is also noted that properly aged MA alloys can develop a better combination of yield strength and notched toughness at lower alloying levels.

  12. Formation and evolution of nanoporous bimetallic Ag-Cu alloy by electrochemically dealloying Mg-(Ag-Cu)-Y metallic glass

    International Nuclear Information System (INIS)

    Li, Ran; Wu, Na; Liu, Jijuan; Jin, Yu; Chen, Xiao-Bo; Zhang, Tao

    2017-01-01

    Highlights: • Uniform nanoporous Ag-Cu alloy was fabricated by dealloying Mg-based metallic glass. • The nanoporous structure was built up with numerous Ag-Cu ligaments. • The nanoporous ligaments show two-stage coarsening behavior with dealloying time. • The formation and evolution mechanisms of the nanoporous structure were clarified. • It could provide new guidance to the synthesis of nanoporous multi-component alloys. - Abstract: A three-dimensional nanoporous bimetallic Ag-Cu alloy with uniform chemical composition has been fabricated by dealloying Mg_6_5Ag_1_2_._5Cu_1_2_._5Y_1_0 metallic glass in dilute (0.04 M) H_2SO_4 aqueous solution under free-corrosion conditions. The nanoporous Ag-Cu evolves through two distinct stages. First, ligaments of the nanoporous structure, consisting of supersaturated Ag(Cu) solid solution with a constant Ag/Cu mole ratio of 1:1, are yielded. Second, with excessive immersion, some Cu atoms separate from the metastable nanoporous matrix and form spherical Cu particles on the sample surface. Formation and evolution mechanisms of the nanoporous structure are proposed.

  13. Electrochemical behavior of anodized AA6063-T6 alloys affected by matrix structures

    International Nuclear Information System (INIS)

    Huang, Yung-Sen; Shih, Teng-Shih; Wu, Chen-En

    2013-01-01

    Highlights: ► Deformation after solution treatment introduced Al matrix to have deformation bands and few Si particles. ► Dislocations remained in the matrix lift up field potential and produce AlOOH oxide in the AAO film. ► The silicon-containing particles were found to trap in the AAO film. ► The silicon particles and the Al(OOH) oxide is significantly to influence the electrochemical behavior of AAO films. - Abstract: AA 6063 alloys were cold-rolled (CR) either before or after solution treatment (S) and then different samples were artificially aged (T6) to obtain different samples (CRST6 and SCRT6). The highest dislocation density was observed in the SCRT6 sample which also showed the lowest particle count among the three samples; ST6, CRST6 and SCRT6. Subsequently, all samples were anodized in a 15 wt% sulfuric acid solution for different time spans to obtain anodic aluminum oxide (AAO) films. The anodized samples were further analyzed with X-ray Photoelectron Spectroscopy (XPS) analysis. We determined that the constituent phases in the AAO film were composed of hydrated amorphous alumina, hydrated oxide (Al(OH) 3 ) and oxyhydroxide (AlOOH) phases together with some silicon-containing particles trapped in the films on all samples. In the electrochemical test, the silicon-containing particles and hydrated Al(OH) 3 oxide that existed at the electrolyte/film (e/f) interface were found to inversely influence the corrosion resistance of the anodized samples.

  14. The effect of zinc on the microstructure and phase transformations of casting Al-Cu alloys

    Directory of Open Access Journals (Sweden)

    Manasijević Ivana I.

    2016-01-01

    Full Text Available Copper is one of the main alloying elements for aluminum casting alloys. As an alloying element, copper significantly increases the tensile strength and toughness of alloys based on aluminum. The copper content in the industrial casting aluminum alloys ranges from 3,5 to 11 wt.%. However, despite the positive effect on the mechanical properties, copper has a negative influence on the corrosion resistance of aluminum and its alloys. In order to further improve the properties of Al-Cu alloys they are additional alloyed with elements such as zinc, magnesium and others. In this work experimental and analytical examination of the impact of zinc on the microstructure and phase transformations of Al-Cu alloys was carried out. In order to determine the effect of the addition of zinc to the structure and phase transformations of Al-Cu alloys two alloys of Al-Cu-Zn system with selected compositions were prepared and then examined using scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDX. The experimental results were compared with the results of thermodynamic calculations of phase equilibria.

  15. Preparation of octahedral CuO micro/nanocrystals and electrochemical performance as anode for lithium-ion battery

    International Nuclear Information System (INIS)

    Feng, Lili; Xuan, Zhewen; Bai, Yang; Zhao, Hongbo; Li, Li; Chen, Yashun; Yang, Xianqin; Su, Changwei; Guo, Junming; Chen, Xiaokai

    2014-01-01

    Highlights: • Octahedral cupric oxides with hollow structure were prepared. • No hard template was used in the preparation of hollow cupric oxides. • The cupric oxides show good reversible capacity. - Abstract: Herein we report that three octahedral CuO samples with hollow or solid structure are successfully prepared by firstly preparation of Cu 2 O products using a chemical reduction method, then by calcination in a muffle furnace at 300 °C for 3 h in air atmosphere. The obtained CuO samples serve as a good model system for the study as anodes for lithium ion batteries. All the three CuO samples have high discharge specific capacity and good cycling stability from the 2nd cycling to the 50th cycling. Octahedral CuO hollow crystals with 400 nm in size have the highest reversible capacity and the smallest resistance. So their electrochemical performances are partly related to their morphologies. The results suggest that the as-prepared CuO samples, especially the 400 nm hollow octahedral CuO crystals could be a promising material for the anode of lithium-ion battery

  16. Bonding tungsten, W–Cu-alloy and copper with amorphous Fe–W alloy transition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song, E-mail: wangsongrain@163.com [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); 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); Zang, Nanzhi [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Wang, Jianjun [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Guo, Shibin [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Jun [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Xu, Guiying [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China)

    2013-05-15

    W/Cu graded materials are the leading candidate materials used as the plasma facing components in a fusion reactor. However, tungsten and copper can hardly be jointed together due to their great differences in physical properties such as coefficient of thermal expansion and melting point, and the lack of solid solubility between them. To overcome those difficulties, a new amorphous Fe–W alloy transitional coating and vacuum hot pressing (VHP) method were proposed and introduced in this paper. The morphology, composition and structure of the amorphous Fe–W alloy coating and the sintering interface of the specimens were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The thermal shock resistance of the bonded composite was also tested. The results demonstrated that amorphous structure underwent change from amorphous to nano grains during joining process, and the joined W/Cu composite can endued plasma thermal shock resistance with energy density more than 5.33 MW/m{sup 2}. It provides a new feasible technical to join refractory tungsten to immiscible copper with amorphous Fe–W alloy coating.

  17. Evolution of insoluble eutectic Si particles in anodic oxidation films during adipic-sulfuric acid anodizing processes of ZL114A aluminum alloys

    Science.gov (United States)

    Hua, Lei; Liu, Jian-hua; Li, Song-mei; Yu, Mei; Wang, Lei; Cui, Yong-xin

    2015-03-01

    The effects of insoluble eutectic Si particles on the growth of anodic oxide films on ZL114A aluminum alloy substrates were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The anodic oxidation was performed at 25°C and a constant voltage of 15 V in a solution containing 50 g/L sulfuric acid and 10 g/L adipic acid. The thickness of the formed anodic oxidation film was approximately 7.13 μm. The interpore distance and the diameters of the major pores in the porous layer of the film were within the approximate ranges of 10-20 nm and 5-10 nm, respectively. Insoluble eutectic Si particles strongly influenced the morphology of the anodic oxidation films. The anodic oxidation films exhibited minimal defects and a uniform thickness on the ZL114A substrates; in contrast, when the front of the oxide oxidation films encountered eutectic Si particles, defects such as pits and non-uniform thickness were observed, and pits were observed in the films.

  18. Advances in aluminum anodizing

    Science.gov (United States)

    Dale, K. H.

    1969-01-01

    White anodize is applied to aluminum alloy surfaces by specific surface preparation, anodizing, pigmentation, and sealing techniques. The development techniques resulted in alloys, which are used in space vehicles, with good reflectance values and excellent corrosive resistance.

  19. Kinetic Monte Carlo simulation of surface segregation in Pd–Cu alloys

    International Nuclear Information System (INIS)

    Cheng, Feng; He, Xiang; Chen, Zhao-Xu; Huang, Yu-Gai

    2015-01-01

    The knowledge of surface composition and atomic arrangement is prerequisite for understanding of catalytic properties of an alloy catalyst. Gaining such knowledge is rather difficult, especially for those possessing surface segregation. Pd–Cu alloy is used in many fields and possesses surface segregation. In this paper kinetic Monte Carlo method is used to explore the surface composition and structure and to examine the effects of bulk composition and temperature on the surface segregation of Pd–Cu alloys. It is shown that the segregation basically completes within 900 s at 500 K. Below 900 K and within 20 min the enriched surface Cu atoms mainly come from the top five layers. For the first time we demonstrate that there exists a “bulk-inside flocking” or clustering phenomenon (the same component element congregates in bulk) in Pd–Cu alloys. Our results indicate that for alloys with higher Cu content there are small Pd ensembles like monomers, dimers and trimers with contiguous subsurface Pd atoms. - Highlights: • Kinetic Monte Carlo was first used to study surface segregation of Pd–Cu alloys. • Bulk-inside flocking (the same component element congregates in bulk) was observed. • Small Pd ensembles with contiguous subsurface Pd exist on surfaces of Cu-rich alloys

  20. Kinetic Monte Carlo simulation of surface segregation in Pd–Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feng [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University (China); He, Xiang [Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Chen, Zhao-Xu, E-mail: zxchen@nju.edu.cn [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University (China); Huang, Yu-Gai [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University (China); JiangSu Second Normal University, Nanjing (China)

    2015-11-05

    The knowledge of surface composition and atomic arrangement is prerequisite for understanding of catalytic properties of an alloy catalyst. Gaining such knowledge is rather difficult, especially for those possessing surface segregation. Pd–Cu alloy is used in many fields and possesses surface segregation. In this paper kinetic Monte Carlo method is used to explore the surface composition and structure and to examine the effects of bulk composition and temperature on the surface segregation of Pd–Cu alloys. It is shown that the segregation basically completes within 900 s at 500 K. Below 900 K and within 20 min the enriched surface Cu atoms mainly come from the top five layers. For the first time we demonstrate that there exists a “bulk-inside flocking” or clustering phenomenon (the same component element congregates in bulk) in Pd–Cu alloys. Our results indicate that for alloys with higher Cu content there are small Pd ensembles like monomers, dimers and trimers with contiguous subsurface Pd atoms. - Highlights: • Kinetic Monte Carlo was first used to study surface segregation of Pd–Cu alloys. • Bulk-inside flocking (the same component element congregates in bulk) was observed. • Small Pd ensembles with contiguous subsurface Pd exist on surfaces of Cu-rich alloys.

  1. Influence of 8-hydroxyquinoline on properties of anodic coatings obtained by micro arc oxidation on AZ91 magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.F. [Jiangxi Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); School of Material Science and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Zhang, S.F., E-mail: zhangshufang790314@sina.com [Jiangxi Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); School of Material Science and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Yang, N.; Yao, L.J.; He, F.X.; Zhou, Y.P.; Xu, X.; Chang, L.; Bai, S.J. [School of Material Science and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China)

    2012-10-25

    Highlights: Black-Right-Pointing-Pointer 8-HQ can promote the coating formation and change the coating color. Black-Right-Pointing-Pointer 8-HQ can increase the coating thickness and decrease the pore size. Black-Right-Pointing-Pointer Insoluble Mg(HQ){sub 2} is formed in anodic coatings in an alkaline solution with 8-HQ. Black-Right-Pointing-Pointer 8-HQ improves the corrosion resistance of the anodized magnesium alloys. - Abstract: The influence of 8-hydroxyquinoline (8-HQ) on formation and properties of anodic coatings obtained by micro arc oxidation (MAO) on AZ91 magnesium alloys was studied by scanning electron microscope (SEM), energy dispersive spectrometry (EDS), Fourier transform infrared (FT-IR) spectroscopy and potentiodynamic polarization tests. The results demonstrate that 8-HQ can decrease the solution conductivity, take part in the coating formation and change the coating color. By developing anodic coatings with increasing thickness, insoluble Mg(HQ){sub 2} and small pore size, 8-HQ improves the corrosion resistance of the anodized magnesium alloys. The coating shows the best corrosion resistance in the solution of 10 g/L NaOH and 18 g/L Na{sub 2}SiO{sub 3} with 2 g/L 8-HQ.

  2. 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.

  3. 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.

  4. Size Control of Alloyed Cu-In-Zn-S Nanoflowers

    Directory of Open Access Journals (Sweden)

    Björn Kempken

    2015-01-01

    Full Text Available Uniform, alloyed Cu-In-Zn-S nanoflowers with sizes of 11.5±2.1 nm and 31±5 nm composed of aggregated 4.1 nm and 5.6 nm primary crystallites, respectively, were obtained in a one-pot, heat-up reaction between copper, indium, and zinc acetate with tert-dodecanethiol in the presence of trioctylphosphine oxide. Larger aggregates were obtained by diluting tert-dodecanethiol with oleylamine, which lowered the reactivity of the indium and zinc precursors and led to the formation of copper rich particles. The thermal decomposition of tert-dodecanethiol stabilizing the primary crystallites induced their agglomeration, while the presence of trioctylphosphine oxide on the surface of the nanoflowers provided them with colloidal stability and prevented them from further aggregation.

  5. Synergetic effects in CO adsorption on Cu-Pd(111) alloys

    DEFF Research Database (Denmark)

    Lopez, Nuria; Nørskov, Jens Kehlet

    2001-01-01

    We present density functional calculations for the interaction of CO on different Cu-Pd(111) bulk and surface alloys. The modification of the adsorption properties with respect to hose of the adsorption on pure Cu(111) and Pd(111) is described in terms of changes in the adsorption sites...... and the change of the electronic structure occurring upon alloying. The presence of cooperative, synergetic. effects is found to be important specially for Cu-rich bulk alloys. In this case. a larger adsorption energy is found for the inactive component than for the pure inactive system. This activation induces...

  6. Ductile shape memory alloys of the Cu-Al-Mn system

    International Nuclear Information System (INIS)

    Kainuma, R.; Takahashi, S.; Ishida, K.

    1995-01-01

    Cu-Al-Mn shape memory alloys with enhanced ductility have been developed by decreasing the degree of order in the β parent phase. Cu-Al-Mn alloys with Al contents lower than 18% exhibit good ductility with elongations of about 15% and excellent cold-workability arising from a lower degree of order in the Heusler (L21) β 1 parent phase, without any loss in their shape memory behavior. In this paper the mechanical and shape memory characteristics, such as the cold-workability, the Ms temperatures, the shape memory effect and the pseudo-elasticity of such ductile Cu-Al-Mn alloys are presented. (orig.)

  7. Wettability of zirconium diboride ceramics by Ag, Cu and their alloys with Zr

    International Nuclear Information System (INIS)

    Muolo, M.L.; Ferrera, E.; Novakovic, R.; Passerone, A.

    2003-01-01

    Sintered ZrB 2 ceramics, pure and with 4 wt.% Ni as sintering aid, have been tested in contact with liquid Ag, Cu, Ag-Cu and Ag-Cu-Zr. ''Pure'' ZrB 2 ceramics are wetted by Ag-Zr alloys, and ZrB 2 /Ni ceramics also by pure Cu. The wetting behaviour is briefly discussed in terms of existing wetting theories

  8. The mineralogical characterization of tellurium in copper anodes

    Science.gov (United States)

    Chen, T. T.; Dutrizac, J. E.

    1993-12-01

    A mineralogical study of a «normal» commercial copper anode and six tellurium-rich copper anodes from the CCR Refinery of the Noranda Copper Smelting and Refining Company was carried out to identify the tellurium carriers and their relative abundances. In all the anodes, the major tellurium carrier is the Cu2Se-Cu2Te phase which occurs as a constituent of complex inclusions at the copper grain boundaries. In tellurium-rich anodes, the molar tellurium content of the Cu2Se-Cu2Te phase can exceed that of selenium. Although >85 pct of the tellurium occurs as the Cu2Se-Cu2Te phase, minor amounts are present in Cu-Pb-As-Bi-Sb oxide, Cu-Bi-As oxide, and Cu-Te-As oxide phases which form part of the grain-boundary inclusions. About 1 pct of the tellurium content of silver-rich anodes occurs in various silver alloys, but gold tellurides were never detected. Surprising is the fact that 2 to 8 pct of the total tellurium content of the anodes occurs in solid solution in the copper-metal matrix, and presumably, this form of tellurium dissolves at the anode interface during electrorefining.

  9. Alloying behavior of iron, gold and silver in AlCoCrCuNi-based equimolar high-entropy alloys

    International Nuclear Information System (INIS)

    Hsu, U.S.; Hung, U.D.; Yeh, J.W.; Chen, S.K.; Huang, Y.S.; Yang, C.C.

    2007-01-01

    High-entropy alloys are newly developed alloys that are composed, by definition, of at least five principal elements with concentrations in the range of 5-35 at.%. Therefore, the alloying behavior of any given principal element is significantly affected by all the other principal elements present. In order to elucidate this further, the influence of iron, silver and gold addition on the microstructure and hardness of AlCoCrCuNi-based equimolar alloys has been examined. The as-cast AlCoCrCuNi base alloy is found to have a dendritic structure, of which only solid solution FCC and BCC phases can be observed. The BCC dendrite has a chemical composition close to that of the nominal alloy, with a deficiency in copper however, which is found to segregate and form a FCC Cu-rich interdendrite. The microstructure of the iron containing alloys is similar to that of the base alloy. It is found that both of these aforementioned alloys have hardnesses of about 420 HV, which is equated to their similar microstructures. The as-cast ingot forms two layers of distinct composition with the addition of silver. These layers, which are gold and silver in color, are determined to have a hypoeutectic Ag-Cu composition and a multielement mixture of the other principal elements, respectively. This indicates the chemical incompatibility of silver with the other principal elements. The hardnesses of the gold (104 HV) and silver layers (451 HV) are the lowest and highest of the alloy systems studied. This is attributed to the hypoeutectic Ag-Cu composition of the former and the reduced copper content of the latter. Only multielement mixtures, i.e. without copper segregation, form in the gold containing alloy. Thus, it may be said that gold acts as a 'mixing agent' between copper and the other elements. Although several of the atom pairs in the gold containing alloy have positive enthalpies, thermodynamic considerations show that the high entropy contribution is sufficient to counterbalance

  10. Surface tension of liquid Cu-Ti binary alloys measured by electromagnetic levitation and thermodynamic modelling

    International Nuclear Information System (INIS)

    Amore, S.; Brillo, J.; Egry, I.; Novakovic, R.

    2011-01-01

    The surface tension of liquid Cu-Ti alloys has been measured by using the containerless technique of electromagnetic levitation and theoretically calculated in the framework of the compound formation model. Measurements have been carried out on alloys covering the entire range of composition and over the temperature range 1275-2050 K. For all investigated alloys the surface tension can be described by a linear function of the temperature with negative slope. Due to the presence of different intermetallic compounds in the solid state the surface properties of liquid Cu-Ti alloys are satisfactory described by the compound formation model.

  11. Formation and structure of nanocrystalline Al-Mn-Ni-Cu alloys

    International Nuclear Information System (INIS)

    Latuch, J.; Krasnowski, M.; Ciesielska, B.

    2002-01-01

    This paper reports the results of the short investigation on the effect of Cu additions upon the nanocrystallization behaviour of an Al-Mn-Ni alloy. 2 at.% Cu added to the base alloy of Al 85 Mn 10 Ni 5 alloy by substitution for Mn(mischmetal). The control of cooling rate did not cause the formation of nanocrystals of fcc-Al phase. The nanocrystalline structure fcc-Al + amorphous phase in quarternary alloy was obtained by isothermal annealing and continuous heating method, but the last technique is more effective. The volume fraction, lattice parameter, and size of Al-phase were calculated. (author)

  12. Effect of Cu Alloying on S Poisoning of Ni Surfaces and Nanoparticle Morphologies Using Ab-Initio Thermodynamics Calculations.

    Science.gov (United States)

    Kim, Ji-Su; Kim, Byung-Kook; Kim, Yeong-Cheol

    2015-10-01

    We investigated the effect of Cu alloying on S poisoning of Ni surfaces and nanoparticle morphologies using ab-initio thermodynamics calculations. Based on the Cu segregation energy and the S adsorption energy, the surface energy and nanoparticle morphology of pure Ni, pure Cu, and NiCu alloys were evaluated as functions of the chemical potential of S and the surface orientations of (100), (110), and (111). The constructed nanoparticle morphology was varied as a function of chemical potential of S. We find that the Cu added to Ni for NiCu alloys is strongly segregated into the top surface, and increases the S tolerance of the NiCu nanoparticles.

  13. 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%

  14. Preparation and electrochemical performances of cubic shape Cu2O as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhang, C.Q.; Tu, J.P.; Huang, X.H.; Yuan, Y.F.; Chen, X.T.; Mao, F.

    2007-01-01

    Cubic and star-shaped crystalline Cu 2 O particles were synthesized by reducing the copper citrate complex solution with glucose. The microstructure and morphology of the Cu 2 O were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the Cu 2 O as anode materials for lithium ion batteries were measured by galvanostatic charge-discharge tests. The as-synthesized Cu 2 O particles were 1-2 μm with narrow distribution and the shape of Cu 2 O particles had an effect on the electrochemical properties. The cubic Cu 2 O particles delivered a higher reversible discharge capacity (390 mAh g -1 ) than the star-shaped Cu 2 O, and also exhibited good cyclability. The star-shaped Cu 2 O particles presented poor cyclability due to pulverization and deterioration after cycling, but the morphology of the cubic Cu 2 O particles was stable even after 50 cycles

  15. A three-dimensional hierarchical nanoporous PdCu alloy for enhanced electrocatalysis and biosensing

    International Nuclear Information System (INIS)

    Liu Aihua; Geng Haoran; Xu Caixia; Qiu Huajun

    2011-01-01

    Highlights: → Nanotubular mesoporous PdCu (NM-PdCu) alloy is facilely fabricated via one-step metal replacement reaction between nanoporous Cu and H 2 PdCl 4 . → The NM-PdCu exhibits remarkably improved structure stability and electrocatalytic activity towards formic acid and hydrogen peroxide oxidation compared with NP-Pd. → When coupled with GOx, the GOx/NM-PdCu electrode can be used for sensitive detection of glucose over a wide concentration range. - Abstract: Nanoporous copper (NPC) obtained by dealloying CuAl alloy is used as both three-dimensional template and reducing agent for the fabrication of nanoporous PdCu alloy with hollow ligaments by a simple galvanic replacement reaction with H 2 PdCl 4 aqueous solution. Electron microscopy and X-ray diffraction characterizations demonstrate that after the replacement reaction, the ligaments become hollow tubular structure and the ligament shell is also comprised of small pores and nanoparticles with a typical size of ∼4 nm (third order porosity). The as-prepared nanotubular mesoporous PdCu alloy (NM-PdCu) structure exhibits remarkably improved electrocatalytic activity towards the oxidation of formic acid and H 2 O 2 compared with nanoporous Pd (NP-Pd), and can be used for sensitive electrochemical sensing applications. After coupled with glucose oxidase (GOx), the enzyme modified NM-PdCu electrode can sensitively detect glucose over a wide linear range (0.5-20 mM).

  16. Manufacturing and characterization of magnesium alloy foils for use as anode materials in rechargeable magnesium ion batteries

    Science.gov (United States)

    Schloffer, Daniel; Bozorgi, Salar; Sherstnev, Pavel; Lenardt, Christian; Gollas, Bernhard

    2017-11-01

    The fabrication of thin foils of magnesium for use as anode material in rechargeable magnesium ion batteries is described. In order to improve its workability, the magnesium was alloyed by melting metallurgy with zinc and/or gadolinium, producing saturated solid solutions. The material was extruded to thin foils and rolled to a thickness of approximately 100 μm. The electrochemical behavior of Mg-1.63 wt% Zn, Mg-1.55 wt% Gd and Mg-1.02 wt% Zn-1.01 wt% Gd was studied in (PhMgCl)2-AlCl3/THF electrolyte by cyclic voltammetry and galvanostatic cycling in symmetrical cells. Analysis of the current-potential curves in the Tafel region and the linear region close to the equilibrium potential show almost no effect of the alloying elements on the exchange current densities (5-45 μA/cm2) and the transfer coefficients. Chemical analyses of the alloy surfaces and the electrolyte demonstrate that the alloying elements not only dissolve with the magnesium during the anodic half-cycles, but also re-deposit during the cathodic half-cycles together with the magnesium and aluminum from the electrolyte. Given the negligible corrosion rate in aprotic electrolytes under such conditions, no adverse effects of alloying elements are expected for the performance of magnesium anodes in secondary batteries.

  17. Formation of barrier-type anodic films on ZE41 magnesium alloy in a fluoride/glycerol electrolyte

    International Nuclear Information System (INIS)

    Hernández-López, J.M.; Němcová, A.; Zhong, X.L.; Liu, H.; Arenas, M.A.; Haigh, S.J.; Burke, M.G.; Skeldon, P.; Thompson, G.E.

    2014-01-01

    Highlights: • Barrier anodic films formed on ZE41 Mg alloy in glycerol/fluoride electrolyte. • Films contain oxygen and fluorine species; formation ratio ∼1.3 nm V −1 . • Nanocrystalline film structure, with MgO and MgF 2. • Zinc enrichment in alloy beneath anodic film. • Modified film formed above Mg-Zn-RE second phase. - Abstract: Barrier-type, nanocrystalline anodic films have been formed on a ZE41 magnesium alloy under a constant current density of 5 mA cm −2 in a glycerol/fluoride electrolyte, containing 5 vol.% of added water, at 293 K. The films contain magnesium, fluorine and oxygen as the major species, and lower amounts of alloying element species. The films grow at an efficiency of ∼0.8 to 0.9, with a formation ratio in the range of ∼1.2 to 1.4 nm V −1 at the matrix regions and with a ratio of ∼1.8 nm V −1 at Mg-Zn-RE second phase. At the former regions, rare earth species are enriched at the film surface and zinc is enriched in the alloy. A carbon- and oxygen-rich band within the film suggests that the films grow at the metal/film and film/electrolyte interfaces

  18. Using sewage sludge pyrolytic gas to modify titanium alloy to obtain high-performance anodes in bio-electrochemical systems

    Science.gov (United States)

    Gu, Yuan; Ying, Kang; Shen, Dongsheng; Huang, Lijie; Ying, Xianbin; Huang, Haoqian; Cheng, Kun; Chen, Jiazheng; Zhou, Yuyang; Chen, Ting; Feng, Huajun

    2017-12-01

    Titanium is under consideration as a potential stable bio-anode because of its high conductivity, suitable mechanical properties, and electrochemical inertness in the operating potential window of bio-electrochemical systems; however, its application is limited by its poor electron-transfer capacity with electroactive bacteria and weak ability to form biofilms on its hydrophobic surface. This study reports an effective and low-cost way to convert a hydrophobic titanium alloy surface into a hydrophilic surface that can be used as a bio-electrode with higher electron-transfer rates. Pyrolytic gas of sewage sludge is used to modify the titanium alloy. The current generation, anodic biofilm formation surface, and hydrophobicity are systematically investigated by comparing bare electrodes with three modified electrodes. Maximum current density (15.80 A/m2), achieved using a modified electrode, is 316-fold higher than that of the bare titanium alloy electrode (0.05 A/m2) and that achieved by titanium alloy electrodes modified by other methods (12.70 A/m2). The pyrolytic gas-modified titanium alloy electrode can be used as a high-performance and scalable bio-anode for bio-electrochemical systems because of its high electron-transfer rates, hydrophilic nature, and ability to achieve high current density.

  19. Cu-Al alloy formation by thermal annealing of Cu/Al multilayer films deposited by cyclic metal organic chemical vapor deposition

    Science.gov (United States)

    Moon, Hock Key; Yoon, Jaehong; Kim, Hyungjun; Lee, Nae-Eung

    2013-05-01

    One of the most important issues in future Cu-based interconnects is to suppress the resistivity increase in the Cu interconnect line while decreasing the line width below 30 nm. For the purpose of mitigating the resistivity increase in the nanoscale Cu line, alloying Cu with traces of other elements is investigated. The formation of a Cu alloy layer using chemical vapor deposition or electroplating has been rarely studied because of the difficulty in forming Cu alloys with elements such as Al. In this work, Cu-Al alloy films were successfully formed after thermal annealing of Cu/Al multilayers deposited by cyclic metal-organic chemical vapor deposition (C-MOCVD). After the C-MOCVD of Cu/Al multilayers without gas phase reaction between the Cu and Al precursors in the reactor, thermal annealing was used to form Cu-Al alloy films with a small Al content fraction. The resistivity of the alloy films was dependent on the Al precursor delivery time and was lower than that of the aluminum-free Cu film. No presence of intermetallic compounds were detected in the alloy films by X-ray diffraction measurements and transmission electron spectroscopy.

  20. Mechanism of abnormally slow crystal growth of CuZr alloy

    International Nuclear Information System (INIS)

    Yan, X. Q.; Lü, Y. J.

    2015-01-01

    Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed

  1. High-temperature deformation of dispersion-strengthened Cu-Zr-Ti-C alloys

    International Nuclear Information System (INIS)

    Palma, Rodrigo H.; Sepulveda, Aquiles; Espinoza, Rodrigo; Dianez, M. Jesus; Criado, Jose M.; Sayagues, M. Jesus

    2005-01-01

    The hot mechanical behaviour and microstructure of Cu-5 vol.% TiC, Cu-5 vol.% ZrO 2 and Cu-2.5 vol.% TiC-2.5 vol.% ZrO 2 alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu-5 vol.% ZrO 2 alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 x 10 -3 and 0.85 x 10 -4 s -1 were performed. The Cu-2.5 vol.% TiC-2.5 vol.% ZrO 2 and the Cu-5 vol.% ZrO 2 alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu-5 vol.% TiC and Cu-5 vol.% ZrO 2 alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures

  2. A novel tin-bismuth alloy electrode for anodic stripping voltammetric determination of zinc

    International Nuclear Information System (INIS)

    Pan, D.; Yin, T.; Qin, W.; Zhang, L.; Zhuang, J.

    2012-01-01

    We report on a novel tin-bismuth alloy electrode (SnBiE) for the determination of trace concentrations of zinc ions by square-wave anodic stripping voltammetry without deoxygenation. The SnBiE has the advantages of easy fabrication and low cost, and does not require a pre-treatment (in terms of modification) prior to measurements. A study on the potential window of the electrode revealed a high hydrogen overvoltage though a limited anodic range due to the oxidation of tin. The effects of pH value, accumulation potential, and accumulation time were optimized with respect to the determination of trace zinc(II) at pH 5. 0. The response of the SnBiE to zinc(II) ion is linear in the 0.5-25 μM concentration range. The detection limit is 50 nM (after 60 s of accumulation). The SnBiE was applied to the determination of zinc(II) in wines and honeys, and the results were consistent with those of AAS. (author)

  3. Cu assisted synthesis of self-supported PdCu alloy nanowires with enhanced performances toward ethylene glycol electrooxidation

    Science.gov (United States)

    Yan, Bo; Xu, Hui; Zhang, Ke; Li, Shujin; Wang, Jin; Shi, Yuting; Du, Yukou

    2018-03-01

    Self-supported PdCu alloy nanowires fabricated by a facile one-pot method have been reported, which copper assists in the morphological transformation from graininess to nanowires. The copper incorporated with palladium to form alloy structures cannot only cut down the usage of noble metal but also enhance their catalytic performances. The catalysts with self-supported structure and proper ratio of palladium to copper show great activity and long-term stability for the electrooxidation of ethylene glycol in alkaline solution. Especially for Pd43Cu57, its mass activity reaches to 5570.83 mA mg-1, which is 3.12 times as high as commercial Pd/C. This study highlights an accessible strategy to prepare self-supported PdCu alloy nanowires and their potential applications in renewable energy fields.

  4. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg alloys

    Directory of Open Access Journals (Sweden)

    M. Kaczorowski

    2007-04-01

    Full Text Available The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening heat treatment. The age hardened specimens were evaluated using tensile test, hardness measurements and impact test. Moreover, the structure investigation were carried out using either conventional light Metallography and scanning (SEM and transmission (TEM electron microscopy. The two last methods were used for fractography observations and precipitation process observations respectively. It was concluded that the changes in chemical composition which can reach even 2,5wt.% cause essential differences of the structure and mechanical properties of the alloys. As followed from quantitative evaluation and as could be predicted theoretically, copper and silicon mostly influenced the mechanical properties of AlSi5Cu3(Mg type cast alloys. Moreover it was showed that the total concentration of alloying elements accelerated and intensifies the process of decomposition of supersaturated solid solution. The increase of Cu and Mg concentration increased the density of precipitates. It increases of strength properties of the alloys which are accompanied with decreasing in ductility.

  5. Cu-based shape memory alloys with enhanced thermal stability and mechanical properties

    International Nuclear Information System (INIS)

    Chung, C.Y.; Lam, C.W.H.

    1999-01-01

    Cu-based shape memory alloys were developed in the 1960s. They show excellent thermoelastic martensitic transformation. However the problems in mechanical properties and thermal instability have inhibited them from becoming promising engineering alloys. A new Cu-Zn-Al-Mn-Zr Cu-based shape memory alloy has been developed. With the addition of Mn and Zr, the martensitic transformation behaviour and the grain size ca be better controlled. The new alloys demonstrates good mechanical properties with ultimate tensile strenght and ductility, being 460 MPa and 9%, respectively. Experimental results revealed that the alloy has better thermal stability, i.e. martensite stabilisation is less serious. In ordinary Cu-Zn-Al alloys, martensite stabilisation usually occurs at room temperature. The new alloy shows better thermal stability even at elevated temperature (∝150 C, >A f =80 C). A limited small amount of martensite stabilisation was observed upon ageing of the direct quenched samples as well as the step quenched samples. This implies that the thermal stability of the new alloy is less dependent on the quenching procedure. Furthermore, such minor martensite stabilisation can be removed by subsequent suitable parent phase ageing. The new alloy is ideal for engineering applications because of its better thermal stability and better mechanical properties. (orig.)

  6. Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate.

    Science.gov (United States)

    Odnevall Wallinder, Inger; Zhang, Xian; Goidanich, Sara; Le Bozec, Nathalie; Herting, Gunilla; Leygraf, Christofer

    2014-02-15

    Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn>Cu sheet>Cu15Zn>Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu2(OH)3Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn5(OH)6(CO3)2 (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)16CO3·4H2O/Zn2Al(OH)6Cl·2H2O/Zn5Cl2(OH)8·H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu2(OH)3Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish-reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Evaluation of mechanical alloying to obtain Cu-Al-Nb shape memory alloy

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Amorim da Silva

    2005-06-01

    Full Text Available The technical viability of preparing a Cu-Al-Nb shape memory alloy by high energy ball milling in a planetary mill has been evaluated. The alloy Cu-13Al-2Nb (wt. (% was prepared by mixing pure elemental powders. A ball-to-powder weight ratio of 6:1 and rotation rate of 150 rpm in argon atmosphere were the main processing parameters. The milling time ranged from 1 to 65 hours. Changes in microstructure as a function of milling time were investigated, using X-ray diffraction analysis and scanning electron microscopy. To investigate the viability of producing sintered parts from milled powders, the conventional powder metallurgy route was used. The milled powders were compacted in a cylindrical die at 900 MPa. Sintering was carried out in argon atmosphere at 850 °C for 6 hours. This study has shown that high energy ball milling, combined with pressing and sintering, can be used to promote the formation of a copper-aluminum solid solution and achieve final sintered densities of 91% of the theoretical density.

  8. Thermomechanical Treatments on High Strength Al-Zn-Mg(-Cu) Alloys

    National Research Council Canada - National Science Library

    Di Russo, E; Conserva, M; Gatto, F

    1974-01-01

    An investigation was carried out to determine the metallurgical properties of Al-Zn-Mg and Al-Zn-Mg-Cu alloy products processed according to newly developed Final Thermomechanical Treatments (FTMT) of T-AHA type...

  9. Evaluation of the microstructure of Al-Cu-Li-Ag-Mg Weldalite (tm) alloys, part 4

    Science.gov (United States)

    Pickens, Joseph R.; Kumar, K. S.; Brown, S. A.; Gayle, Frank W.

    1991-01-01

    Weldalite (trademark) 049 is an Al-Cu-Li-Ag-Mg alloy designed to have ultrahigh strength and to serve in aerospace applications. The alloy displays significantly higher strength than competitive alloys in both naturally aged and artificially aged tempers. The strengthening phases in such tempers have been identified to, in part, explain the mechanical properties attained. In general, the alloy is strengthened by delta prime Al3Li and Guinier-Preston (GP) zones in the naturally aged tempers. In artificially aged tempers in slightly underaged conditions, strengthening is provided by several phases including GP zones, theta prime Al2Cu, S prime Al2CuMg, T(sub 1) Al2CuLi, and possibly a new phase. In the peak strength artificially aged tempers, T(sub 1) is the predominant strengthening phase.

  10. The W alloying effect on thermal stability and hardening of nanostructured Cu-W alloyed thin films.

    Science.gov (United States)

    Zhao, J T; Zhang, J Y; Hou, Z Q; Wu, K; Feng, X B; Liu, G; Sun, J

    2018-05-11

    In order to achieve desired mechanical properties of alloys by manipulating grain boundaries (GBs) via solute decoration, it is of great significance to understand the underlying mechanisms of microstructural evolution and plastic deformation. In this work, nanocrystalline (NC) Cu-W alloyed films with W concentrations spanning from 0 to 40 at% were prepared by using magnetron sputtering. Thermal stability (within the temperature range of 200 °C-600 °C) and hardness of the films were investigated by using the x-ray diffraction, transmission electron microscope (TEM) and nanoindentation, respectively. The NC pure Cu film exhibited substantial grain growth upon all annealing temperatures. The Cu-W alloyed films, however, displayed distinct microstructural evolution that depended not only on the W concentration but also on the annealing temperature. At a low temperature of 200 °C, all the Cu-W alloyed films were highly stable, with unconspicuous change in grain sizes. At high temperatures of 400 °C and 600 °C, the microstructural evolution was greatly controlled by the W concentrations. The Cu-W films with low W concentration manifested abnormal grain growth (AGG), while the ones with high W concentrations showed phase separation. TEM observations unveiled that the AGG in the Cu-W alloyed thin films was rationalized by GB migration. Nanoindentation results showed that, although the hardness of both the as-deposited and annealed Cu-W alloyed thin films monotonically increased with W concentrations, a transition from annealing hardening to annealing softening was interestingly observed at the critical W addition of ∼25 at%. It was further revealed that an enhanced GB segregation associated with detwinning was responsible for the annealing hardening, while a reduced solid solution hardening for the annealing softening.

  11. Particle Based Alloying by Accumulative Roll Bonding in the System Al-Cu

    Directory of Open Access Journals (Sweden)

    Mathias Göken

    2011-11-01

    Full Text Available The formation of alloys by particle reinforcement during accumulative roll bonding (ARB, and subsequent annealing, is introduced on the basis of the binary alloy system Al-Cu, where strength and electrical conductivity are examined in different microstructural states. An ultimate tensile strength (UTS of 430 MPa for Al with 1.4 vol.% Cu was reached after three ARB cycles, which almost equals UTS of the commercially available Al-Cu alloy AA2017A with a similar copper content. Regarding electrical conductivity, the UFG structure had no significant influence. Alloying of aluminum with copper leads to a linear decrease in conductivity of 0.78 µΩ∙cm/at.% following the Nordheim rule. On the copper-rich side, alloying with aluminum leads to a slight strengthening, but drastically reduces conductivity. A linear decrease of electrical conductivity of 1.19 µΩ∙cm/at.% was obtained.

  12. High performance ceramic carbon electrode-based anodes for use in the Cu-Cl thermochemical cycle for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, Santhanam; Easton, E. Bradley [Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario L1H 7K4 (Canada)

    2010-02-15

    A high performance ceramic carbon electrode (CCE) was fabricated by the sol-gel method to study the CuCl electrolysis in Cu-Cl thermochemical cycle. The electrochemical behavior and stability of the CCE was investigated by polarization experiments at different concentrations of CuCl/HCl system. The CCE displayed excellent anodic performance and vastly outperformed the bare carbon fiber paper (CFP) even at high concentrations of CuCl (0.5 M) and HCl (6 M), which is explained in terms of increased active area and enhanced anion transport properties. Further enhancement of activity was achieved by coating the CCE layer onto both sides of the CFP substrate. (author)

  13. Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys

    International Nuclear Information System (INIS)

    Witusiewicz, V.T.; Sommer, F.

    2000-01-01

    Since the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state, it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously, are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent canaries and ternaries first. In a series of articles, the authors have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni, Cu-Zr, Al-Zr, Al-Cu-Ni, and Al-Cu-Zr alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni 26 Zr 74 . In a subsequent article, the authors will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys

  14. Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

    KAUST Repository

    Min, Shixiong

    2017-03-21

    A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH and 27% for CO production was achieved with the current density of 1.5 mA cm-2 at −0.64 V vs. RHE, much higher than that of polycrystalline Cu. The enhanced catalytic performance is a result of the formation of the high electrochemical active surface area and high density of preferred low-index facets.

  15. Effects of benzotriazole on anodized film formed on AZ31B magnesium alloy in environmental-friendly electrolyte

    International Nuclear Information System (INIS)

    Guo Xinghua; An Maozhong; Yang Peixia; Li Haixian; Su Caina

    2009-01-01

    An environmental-friendly electrolyte of silicate and borate, which contained an addition agent of 1H-benzotriazole (BTA) with low toxicity (LD50 of 965 mg/kg), was used to prepare an anodized film on AZ31B magnesium alloy under the constant current density of 1.5 A/dm 2 at room temperature. Effects of BTA on the properties of the anodized film were studied by scanning electron microscopy (SEM), energy dispersion spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), loss weight measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), respectively. The results demonstrated that anodized growth process, surface morphology, thickness, phase structure and corrosion resistance of the anodized film were strongly dependant on the BTA concentration, which might be attributed to the formation of an BTA adsorption layer on magnesium substrate surface. When the BTA concentration was 5 g/L in the electrolyte, a compact and thick anodized film could provide excellent corrosion resistance for AZ31B magnesium alloy.

  16. Preparation of Advanced CuO Nanowires/Functionalized Graphene Composite Anode Material for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jin Zhang

    2017-01-01

    Full Text Available The copper oxide (CuO nanowires/functionalized graphene (f-graphene composite material was successfully composed by a one-pot synthesis method. The f-graphene synthesized through the Birch reduction chemistry method was modified with functional group “–(CH25COOH”, and the CuO nanowires (NWs were well dispersed in the f-graphene sheets. When used as anode materials in lithium-ion batteries, the composite exhibited good cyclic stability and decent specific capacity of 677 mA·h·g−1 after 50 cycles. CuO NWs can enhance the lithium-ion storage of the composites while the f-graphene effectively resists the volume expansion of the CuO NWs during the galvanostatic charge/discharge cyclic process, and provide a conductive paths for charge transportation. The good electrochemical performance of the synthesized CuO/f-graphene composite suggests great potential of the composite materials for lithium-ion batteries anodes.

  17. The antibacterial properties and biocompatibility of a Ti–Cu sintered alloy for biomedical application

    International Nuclear Information System (INIS)

    Liu, Jie; Zhang, Xinxin; Wang, Hongying; Li, Fangbing; Li, Muqin; Zhang, Erlin; Yang, Ke

    2014-01-01

    The antibacterial activity, the cytotoxicity and the cell function of a sintered Ti-10 wt% Cu alloy were investigated in order to assess the suitability of the alloy for biomedical application. The antibacterial activity of the alloy was investigated by a plate-count method and the cytotoxicity was studied by examining the MG63 cell response by CCK8 assessment. The cell function was monitored by measuring the AKP activity. The Cu ion released from the Ti–Cu alloy was also measured by an inductively coupled plasma spectrometer at different immersion durations. The results show that the antibacterial rates of the alloy against Escherichia coli and Staphylococcus aureus increase with an increase in the incubation duration. After 7 h of incubation, the alloy showed an antibacterial rate of 91.66% against S. aureus and 99. 01% against E. coli. With a further extension of incubation time to 24 h, the antibacterial rate increased to 100% against S. aureus and 99.93% against E. coli. No cytotoxicity was observed on the alloy by a CKK8 test during three days of incubation in comparison with commercially available pure titanium (cp-Ti). AKP test results showed a significantly high AKP value (p = 0.001 < 0.01) on the Ti–Cu alloy on day 1. The Cu ion release was thought to contribute to the strong antibacterial property, but the Cu ion did not lead to cell cytotoxicity. Strong antibacterial activity and good cell biocompatibility suggest that the Ti–Cu alloy could reduce bacterial infection and have a potential application as an implant material. (paper)

  18. Derivative thermo analysis of the near eutectic Al-Si-Cu alloy

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2008-12-01

    Full Text Available For determining of the dependence between cooling Speer, chemical composition and structure of the Al–Si–Cu aluminium cast alloy the thermo-analysis was carried out, using the UMSA device (Universal Metallurgical Simulator and Analyzer, next the optical and electron scanning microscopy was used for investigation of the structure, phase and chemical composition of the AC-AlSi7Cu3Mg grade Al cast alloy also using the EDS microanalysis as well the EBSD technique.

  19. Corrosion Inhibition Study of Al-Cu-Ni Alloy in Simulated Sea-Water ...

    African Journals Online (AJOL)

    A study on the inhibition of Al-Cu-Ni alloy in simulated sea-water environment was investigated using Sodium Chromate as inhibitor. The inhibitor concentration was varied as control, 0.25, 0.5, 1.0, 1.5 and 2.0 Molar. Al-Cu-Ni alloy was sand cast into cylindrical bars of 20 mm x 300 mm dimension. The corrosion of the ...

  20. Microstructure and mechanical properties of AC AlSi9CuX alloys

    OpenAIRE

    L.A. Dobrzański; R. Maniara; M. Krupiński; J.H. Sokołowski

    2007-01-01

    Purpose: In order to gain a better understanding of how to control the as-cast microstructure, it is important to understand the evaluation of microstructure during solidification and understanding how influence the changes of chemical concentration on this microstructure and mechanical properties. In this research, the effect of Cu content on the microstructure and mechanical properties of AC AlSi9CuX series alloys has been investigated.Design/methodology/approach: The experimental alloy ...

  1. Infiltration Behavior Of Mechanical Alloyed 75 wt% Cu-25 wt% WC Powders Into Porous WC Compacts

    Directory of Open Access Journals (Sweden)

    Şelte A.

    2015-06-01

    Full Text Available In this work infiltration behavior of mechanical alloyed 75 wt% Cu – 25 wt% WC powders into porous WC compacts were studied. Owing to their ductile nature, initial Cu powders were directly added to mechanical alloying batch. On the other hand initial WC powders were high energy milled prior to mechanical alloying. Contact infiltration method was selected for densification and compacts prepared from processed powders were infiltrated into porous WC bodies. After infiltration, samples were characterized via X-Ray diffraction studies and microstructural evaluation of the samples was carried out via scanning electron microscopy observations. Based on the lack of solubility between WC and Cu it was possible to keep fine WC particles in Cu melt since solution reprecipitation controlled densification is hindered. Also microstructural characterizations via scanning electron microscopy confirmed that the transport of fine WC fraction from infiltrant to porous WC skeleton can be carried out via Cu melt flow during infiltration.

  2. Research of Mechanical Property Gradient Distribution of Al-Cu Alloy in Centrifugal Casting

    Science.gov (United States)

    Sun, Zhi; Sui, Yanwei; Liu, Aihui; Li, Bangsheng; Guo, Jingjie

    Al-Cu alloy castings are obtained using centrifugal casting. The regularity of mechanical property gradient distribution of Al-Cu alloy castings with the same centrifugal radius at different positions is investigated. The result shows that the tensile strength, yield strength, elongation and microscope hardness exhibit the following gradient distribution characteristic — high on both sides and low on the center. The trend of mechanical property gradient distribution of Al-Cu alloy increases with the increase in the rotation speed. Moreover, the mechanical properties of casting centerline two sides have asymmetry. The reason is that the grain size of casting centerline two sides and Al2Cu phase and Cu content change correspondingly.

  3. A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Memarzadeh, Kaveh [Institute of Dentistry, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Newark Street, London E1 2AT (United Kingdom); Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ren, Guogang [University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Allaker, Robert P., E-mail: r.p.allaker@qmul.ac.uk [Institute of Dentistry, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Newark Street, London E1 2AT (United Kingdom); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2016-10-01

    Objective: The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Methods: Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. Results: SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. Significance: The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. - Highlights: • Novel CoCrCu alloys were fabricated by using selective laser melting (SLM). • SLM CoCrCu alloys showed satisfied antimicrobial and antibiofilm activities. • SLM CoCrCu alloys have no cytotoxic effect on normal cells. • Other properties of SLM CoCrCu alloys were similar to SLM CoCr alloys. • SLM CoCrCu alloys have the potential to be used as coping metals.

  4. A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties

    International Nuclear Information System (INIS)

    Ren, Ling; Memarzadeh, Kaveh; Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang; Ren, Guogang; Allaker, Robert P.; Yang, Ke

    2016-01-01

    Objective: The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Methods: Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. Results: SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. Significance: The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. - Highlights: • Novel CoCrCu alloys were fabricated by using selective laser melting (SLM). • SLM CoCrCu alloys showed satisfied antimicrobial and antibiofilm activities. • SLM CoCrCu alloys have no cytotoxic effect on normal cells. • Other properties of SLM CoCrCu alloys were similar to SLM CoCr alloys. • SLM CoCrCu alloys have the potential to be used as coping metals.

  5. Tem Observation Of Precipitate Structures In Al-Zn-Mg Alloys With Additions Of Cu/Ag

    Directory of Open Access Journals (Sweden)

    Watanabe K.

    2015-06-01

    Full Text Available Al-Zn-Mg alloy has been known as one of the aluminum alloys with the good age-hardening ability and the high strength among commercial aluminum alloys. The mechanical property of the limited ductility, however, is required to further improvement. In this work, three alloys, which were added Cu or Ag into the Al-Zn-Mg alloy, were prepared to compare the effect of the additional elements on the aging behavior. The content of Ag and Cu were 0.2at.% and the same as, respectively. Ag or Cu added alloy showed higher maximum hardness than base alloy. The particle shape and rod shape precipitates were observed in all alloys peak-aged at 423K. According to addition of Ag or Cu, the number density of the precipitates increased higher than that of base alloy.

  6. Evaluation of colloidal Ag and Ag-alloys as anode electrocatalysts for direct borohydride fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Atwan, Mohammed H.; Northwood, Derek O. [Mechanical, Auto, and Materials Engineering, University of Windsor, Windsor, N9B 3P4 (Canada); Gyenge, Elod L. [Chemical and Biological Engineering, The University of British Colombia, Vancouver, BC, V6T 1Z4 (Canada)

    2007-10-15

    In this study, colloidal silver and silver-alloys (Ag-Pt, Ag-Au, Ag-Ir, and Ag-Pd) prepared by the Boenneman technique were evaluated as anode catalysts for sodium borohydride oxidation using cyclic voltammetry (CV), chronoamperometry (CA), chronopotentiometry (CP) and rotating disk electrode (RDE) voltammetry. The CV results show that the colloidal Ag-alloys were electrochemically active towards borohydride oxidation with oxidation potentials ranging between -0.7 and 0.4 V vs. Hg/HgO (MOE). The most negative oxidation potential was recorded on Ag-Pt. CA results show that the steady state current density was highest on Ag-Pt, followed by Ag-Ir, Ag-Au, and Ag-Pd. The lowest overpotential was recorded on Ag-Ir for a current step change of 10mAcm{sup -2}. A significant temperature effect and a small rotation speed effect were found in the rotating disc voltammetry for all the investigated colloids. The highest peak current was recorded on Ag-Au, while the most negative peak potential was recorded on Ag-Ir. (author)

  7. 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.

  8. Dislocation structure evolution and characterization in the compression deformed Mn-Cu alloy

    International Nuclear Information System (INIS)

    Zhong, Y.; Yin, F.; Sakaguchi, T.; Nagai, K.; Yang, K.

    2007-01-01

    Dislocation densities and dislocation structure arrangements in cold compressed polycrystalline commercial M2052 (Mn-20Cu-5Ni-2Fe) high damping alloy with various strains were determined in scanning mode by X-ray peak profile analysis and electron backscatter diffraction (EBSD). The results indicate that the Mn-Cu-Ni-Fe alloy has an evolution behavior quite similar to the dislocation structure in copper. The dislocation arrangement parameter shows a local minimum in the transition range between stages III and IV that can be related to the transformation of the dislocation arrangement in the cell walls from a polarized dipole wall (PDW) into a polarized tile wall (PTW) structure. This evolution is further confirmed by the results of local misorientation determined by EBSD. In addition, during deformation, the multiplication of dislocation densities in the MnCu alloy is significantly slower than that in copper, and the transition of the dislocation structure is strongly retarded in the MnCu alloy compared with copper. These results can be explained by the mechanism of elastic anisotropy on the dislocation dynamics, as the elastic anisotropy in the MnCu alloy is larger than that in copper, which can strongly retard the multiplication of the dislocation population and the transformation of the dislocation structure. These results are important for research into the plastic working behavior of Mn-Cu-Ni-Fe high damping alloy

  9. Corrosion behavior of Zr-x(Nb, Sn and Cu) binary alloys

    International Nuclear Information System (INIS)

    Kim, M. H.; Lee, M. H.; Park, S. Y.; Jung, Y. H.; We, M. Y.

    1999-01-01

    For the development of advanced zirconium alloys for nuclear fuel cladding, the corrosion behaviors of zirconium binary alloys were studied on the Zr-xNb, Zr-xSn, and Zr-xCu alloys. The corrosion test were performed in water at 360 deg C, steam at 400 deg C and LiOH at 360 deg C for 45 days. The corrosion behaviors of Zr-xNb was similar to that of Zr-xCu alloys. However, the corrosion behavior of Zr-xSn was different from Zr-xNb and Zr-xCu. The weight gain of Zr-xNb and Zr-xCu was increased with addition of alloying elements. When Sn is added to Zr matrix in range below the solubility limit, the corrosion resistance decrease with increasing Sn-content, while in the range over solubility limit, Sn has an adverse effect on the corrosion resistance. Especially, Zr-xSn alloys showed higher corrosion resistance than Zr-xNb and Zr-xCu alloys in LiOH solution

  10. New ternary ordered structures in CuMPt6 (M=3d elements) alloys

    International Nuclear Information System (INIS)

    Das, Ananda Kumar; Nakamura, Reo; Takahashi, Miwako; Ohshima, Ken-ichi; Iwasaki, Hiroshi; Shishido, Toetsu

    2006-01-01

    X-ray and electron diffraction measurements were performed to investigate the structure and ordering behaviour of the ternary alloys CuMPt 6 (M=Ti, V, Cr, Mn, Fe, Co, and Ni). X-ray polycrystalline diffraction patterns of all the speciments quenched from 1000degC have shown that a single phase is formed at this stoichiometric composition. The alloys with M=Cr, Mn, Co, and Ni have the face-centred cubic (fcc) structure, while in the alloys with M=Ti, V, and Fe ordering has occurred and the structure is of the Cu 3 Au type. On annealing at lower temperatures ordering has been induced in the alloys with M=Cr, Mn, and Co and the structure is of the Cu 3 Au type, though the ordering in the last alloy has remained incomplete. Detailed X-ray diffraction measurements on single crystals of the CuMnPt 6 alloy have revealed that further ordering takes place and structure changes from the Cu 3 Au type into the cubic ABC 6 type with the unit cell as large 2 x 2 x 2 as the fcc unit cell, a new observation of the double-step ordering in the ternary fcc alloy. The corresponding transition temperatures are T c =970(±5)degC and T cl =750(±5)degC. (author)

  11. Si nanowires/Cu nanowires bilayer fabric as a lithium ion capacitor anode with excellent performance

    Science.gov (United States)

    Lai, Chien-Ming; Kao, Tzu-Lun; Tuan, Hsing-Yu

    2018-03-01

    A light and binder-free bilayer fabric electrode composed of silicon nanowires and copper nanowires for lithium-ion capacitors (LICs) is reported. A lithium ion capacitor is proposed employing pre-lithiated silicon/copper nanowire fabric and activated carbon as the anode and the cathode, respectively. These LICs show remarkable performance with a specific capacitance of 156 F g-1 at 0.1 A g-1, which is approximately twice of that of activated carbon in electric double-layer capacitors (EDLCs), and still exhibit a fine specific capacitance of 68 F g-1 even at a high current density of 20 A g-1. At a low power density of 193 W kg-1, the Si/Cu fabric//AC LIC can achieve high energy density of 210 W h kg-1. As the power density is increased to 99 kW kg-1, the energy density still remains at 43 W h kg-1, showing the prominent rate performance.

  12. Superplastic formability of Al-Cu-Li alloy Weldalite (TM) 049

    Science.gov (United States)

    Ma, Bao-Tong; Pickens, Joseph R.

    1991-01-01

    Extensive research during the past decade shows that several aluminum lithium alloys can be processed to attain a microstructure that enables superplasticity. The high tensile stress of Al-Cu-Li alloy Weldalite (TM) 049 in the T4 and T6 tempers offers tremendous potential for attaining exceptional post-SPF (superplastic formability) properties. The used SPF material is Weldalite, which was shown to induce SPF behavior in other Al-Cu-Li alloys. The superplastic behavior and resulting post-SPF mechanical properties of this alloy, which was designed to be the next major structural alloy for space applications, were evaluated. The results indicate that Weldalite alloy does indeed exhibit excellent superplasticity over a wide range of temperatures and strain rates and excellent post-SPF tensile strength at various potential service temperatures.

  13. Age hardening of a sintered Al-Cu-Mg-Si-(Sn) alloy

    International Nuclear Information System (INIS)

    Kent, D.; Schaffer, G.B.; Drennan, J.

    2005-01-01

    The age hardening response of a sintered Al-3.8 wt% Cu-1.0 wt% Mg-0.70 wt% Si alloy with and without 0.1 wt% Sn was investigated. The sequence of precipitation was characterised using transmission electron microscopy. The ageing response of the sintered Al-Cu-Mg-Si-(Sn) alloy is similar to that of cognate wrought 2xxx series alloys. Peak hardness was associated with a fine, uniform dispersion of lath shaped precipitates, believed to be either the β'or Q' phase, oriented along α directions and θ' plates lying on {0 0 1} α planes. Natural ageing also resulted in comparable behaviour to that observed in wrought alloys. Porosity in the powder metallurgy alloys did not significantly affect the kinetics of precipitation during artificial ageing. Trace levels of tin, used to aid sintering, slightly reduced the hardening response of the alloy. However, this was compensated for by significant improvements in density and hardness

  14. Study of Cu-Al-Ni-Ga as high-temperature shape memory alloys

    Science.gov (United States)

    Zhang, Xin; Wang, Qian; Zhao, Xu; Wang, Fang; Liu, Qingsuo

    2018-03-01

    The effect of Ga element on the microstructure, mechanical properties and shape memory effect of Cu-13.0Al-4.0Ni- xGa (wt%) high-temperature shape memory alloy was investigated by optical microscopy, SEM, XRD and compression test. The microstructure observation results showed that the Cu-13.0Al-4.0Ni- xGa ( x = 0.5 and 1.0) alloys displayed dual-phase morphology which consisted of 18R martensite and (Al, Ga)Cu phase, and their grain size was about several hundred microns, smaller than that of Cu-13.0Al-4.0Ni alloy. The compression test results proved that the mechanical properties of Cu-13.0Al-4.0Ni- xGa alloys were improved by addition of Ga element owing to the grain refinement and solid solution strengthening, and the compressive fracture strains were 11.5% for x = 0.5 and 14.9% for x = 1.0, respectively. When the pre-strain was 8%, the shape memory effect of 4.2 and 4.6% were obtained for Cu-13.0Al-4.0Ni-0.5 Ga and Cu-13.0Al-4.0Ni-1.0 Ga alloys after being heated to 400 °C for 1 min.

  15. Corrosion Inhibition Study of Al-Cu-Ni Alloy in Simulated Sea-Water ...

    African Journals Online (AJOL)

    Akorede

    ABSTRACT: A study on the inhibition of Al-Cu-Ni alloy in simulated ... which the percentage of Copper, and Nickel were kept .... proceed based on equation of reaction in eqn (4). Al .... Sodium-Modified A356.0-Type Al-Si-Mg Alloy in Simulated.

  16. Effect of Ternary Addition of Iron on Shape Memory Characteristics of Cu-Al Alloys

    Science.gov (United States)

    Raju, T. N.; Sampath, V.

    2011-07-01

    The effect of alloying Cu-Al alloys with Fe on their transformation temperatures and shape memory properties was investigated by differential scanning calorimetry and bend test. It was found that the minor additions of iron resulted in change of transformation temperatures and led to excellent shape memory properties of the alloys. Since the transformation temperatures are high, they are an ideal choice for high-temperature applications.

  17. Atomic structure of the SbCu surface alloy: A surface X-ray diffraction study

    DEFF Research Database (Denmark)

    Meunier, I.; Gay, J.M.; Lapena, L.

    1999-01-01

    The dissolution at 400 degrees C of an antimony layer deposited at room temperature on a Cu(111) substrate leads to a surface alloy with a p(root 3x root 3)R 30 degrees x 30 degrees superstructure and a Sb composition of 1/3.We present here a structural study of this Sb-Cu compound by surface X...

  18. Crystallization Behavior of A Bulk Amorphous Mg62Cu26Y12 Alloy

    Science.gov (United States)

    Wu, Shyue-Sheng; Chin, Tsung-Shune; Su, Kuo-Chang

    1994-07-01

    The crystallization temperature, the associated activation energy and the crystallized structure of a bulk amorphous Mg62Cu26Y12 alloy with a diameter of 2.5 mm were studied. It possesses a one-step crystallization behavior. The crystallization reaction was found to be represented by: AM(MG62Cu26Y12)→Mg2Cu+MgY+CuY+Mg, ( Tx=188°C, Eac=134 kJ/mol) where AM represents the amorphous state, T x the crystallization temperature at an infinitesimal heating rate, and E ac the associated activation energy. The amount of crystalline phases were found to be Mg2Cu:MgY:CuY=76:17:7. The Mg phase is identifiable only by high resolution electron microscopy, not by X-ray diffraction. The crystallization leads to a sharp rise in electrical resistivity which is reversed to those of iron-based amorphous alloys.

  19. 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.

  20. Controlled synthesis of uniform ultrafine CuO nanowires as anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang Fei; Tao Weizhe; Zhao Mingshu; Xu Minwei; Yang Shengchun; Sun Zhanbo; Wang Liqun; Song Xiaoping

    2011-01-01

    Highlights: → The ultrafine CuO nanowires were controlled synthesized by a simple solution route. → CuO nanowires exhibit high capacity, superior cyclability and improved rate capability. → Voltage-capacity curves show larger extra reversible reactions at low potentials in CuO nanowires. → CV curves show lower over-potential in CuO nanowires. - Abstract: A simple solution route is used to synthesize ultrafine Cu(OH) 2 nanowires by restraining the morphology transformation of early formed 1D nanostructure. The obtained ultrafine nanowires can be well preserved at a low temperature structure transformation in solid state. As anode material for lithium-ion batteries, the ultrafine CuO nanowires exhibit high reversible capacity, superior cycling performance and improved rate capability. The improved electrochemical properties of CuO nanowires are ascribed to their ultrafine size which lead to the reduced over-potential, extra reversible reactions at low potentials and improved interface performance between the electrode and electrolyte.

  1. Radiation-induced segregation in Cu-Au alloys

    International Nuclear Information System (INIS)

    Hashimoto, T.; Rehn, L.E.; Okamoto, P.R.

    1987-01-01

    Radiation-induced segregation in a Cu-lat.% Au alloy was investigated using in-situ Rutherford backscattering spectrometry. Irradiation with 1.8-MeV helium produced nonequilibrium gold atom depletion in the near surface region. The amount of segregation was measured as a function of dose, dose rate, and temperature. Segregation was observed in the temperature range between about 300 and 500 0 C. For a calculated dose rate of 3.9 x 10/sup -5/ dpa/s, the radiation-induced segregation rate peaked near 400 0 C. Theoretical analysis based on the Johnson-Lam model predicted that the amount of segregation would be directly proportional to dose at the early stage of irradiation, would deviate from linearity with a continuously decreasing slope of intermediate doses, and finally approach a constant value after high doses. The analysis also predicted that the segregation rate would vary as the - 1/4th power of the dose rate at constant dose in the low temperature region. These predictions were all verified experimentally. A procedure for extracting relative defect production efficiencies from similar measurements is discussed

  2. High strength and utilizable ductility of bulk ultrafine-grained Cu-Al alloys

    Science.gov (United States)

    An, X. H.; Han, W. Z.; Huang, C. X.; Zhang, P.; Yang, G.; Wu, S. D.; Zhang, Z. F.

    2008-05-01

    Lack of plasticity is the main drawback for nearly all ultrafine-grained (UFG) materials, which restricts their practical applications. Bulk UFG Cu-Al alloys have been fabricated by using equal channel angular pressing technique. Its ductility was improved to exceed the criteria for structural utility while maintaining a high strength by designing the microstructure via alloying. Factors resulting in the simultaneously enhanced strength and ductility of UFG Cu-Al alloys are the formation of deformation twins and their extensive intersections facilitating accumulation of dislocations.

  3. Effect of Thermomagnetic Treatment on Structure and Properties of Cu-Al-Mn Alloy.

    Science.gov (United States)

    Titenko, A N; Demchenko, L D; Perekos, A O; Gerasimov, O Yu

    2017-12-01

    The paper studies the influence of magnetic field on magnetic and mechanical properties of Cu-Mn-Al alloy under annealing. The comparative analysis of the magnetic field orientation impact on solid solution decomposition processes in a fixed annealing procedure is held using the methods of low-field magnetic susceptibility, specific magnetization, and microhardness test. The paper highlights changes in the magnetic and mechanical properties of Cu-Al-Mn alloy as the result of change in a critical size of forming precipitated ferromagnetic phase and determines correlation in the behavior of magnetic and mechanical properties of the alloy, depending on a critical nucleus size of forming precipitated ferromagnetic phase.

  4. Point defects behavior in beta Cu-based shape memory alloys

    International Nuclear Information System (INIS)

    Romero, R.; Somoza, A.

    1999-01-01

    A summary of positron annihilation spectroscopy data relating to the point defect behavior after quenching and to thermal equilibrium in β-phase Cu-based shape memory alloys Cu-Zn-Al and Cu-Al-Be is presented. Particular attention is given to the initial concentration of quenched-in vacancies as a function of the quenching temperature, migration of the retained point defects with aging temperature and time, and the vacancy formation and migration energies. (orig.)

  5. Low Temperature Mechanical Properties of Scandium-Modified Al-Zn-Mg-Cu Alloys

    National Research Council Canada - National Science Library

    Senkov, O

    2002-01-01

    Tensile properties of three wrought alloys, (1) Al-10Zn-3Mg-1.2Cu-0.15Zr, (2) Al-10Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc, and (3) Al-12Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc were studied in T6 and T7 conditions at 298K and 77K...

  6. HPDL Remelting of Anodised Al-Si-Cu Cast Alloys Surfaces

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2012-12-01

    Full Text Available The results of the investigations of the laser remelting of the AlSi9Cu4 cast aluminium alloy with the anodised and non-anodised surfacelayer and hardness changes have been presented in this paper. The surface layer of the tested aluminium samples was remelted with thelaser of a continuous work. The power density was from 8,17•103 W/cm2 to 1,63•104 W/cm2. The metallographic tests were conducted inform of light microscope investigations of the received surface layer. The main goal of the investigation was to find the relation betweenthe laser beam power and its power density falling on a material, evaluating the shape and geometry of the remelted layers and theirhardness. As the substrate material two types of surfaces of the casted AlSi9Cu4 alloy were applied – the non–treated as cast surface aswell the anodized surface. As a device for this type of surface laser treatment the High Power Diode Laser was applied with a maximumpower of 2.2 kW and the dimensions of the laser beam focus of 1.8 x 6.8 mm. By mind of such treatment it is also possible to increasehardness as well eliminate porosity and develop metallurgical bonding at the coating-substrate interface. Suitable operating conditions forHPDL laser treatment were finally determined, ranging from 1.0 to 2.0 kW. Under such conditions, taking into account the absorptionvalue, the effects of laser remelting on the surface shape and roughness were studied. The results show that surface roughness is reducedwith increasing laser power by the remelting process only for the non-anodised samples, and high porosity can be found in the with highpower remelted areas. The laser influence increases with the heat input of the laser processing as well with the anodisation of the surface,because of the absorption enhancement ensured through the obtained alumina layer.

  7. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    Directory of Open Access Journals (Sweden)

    Xu Chunxiang

    2013-09-01

    Full Text Available To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.% master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu master alloy is 4wt.%. In this case, primary Si and eutectic Si as well as メ-Al phase were clearly refined, and this refining effect shows an excellent long residual action as it can be heat-retained for at least 5 h. After being T6 heat treated, the morphology of primary and eutectic Si in the Al-25Si alloys with the addition of 4wt.% Al-20.6Mn-12Ti-0.9P-6.1Cu alloy changes into particles and short rods. The average grain size of the primary and eutectic Si decreases from 250 レm (unmodified to 13.83 レm and 35 レm (unmodified to 7 レm; the メ-Al becomes obviously finer and the distribution of Si phases tends to be uniform and dispersed. Meanwhile, the tensile properties are improved obviously; the tensile strengths at room temperature and 300 ìC reach 241 MPa and 127 MPa, increased by 153.7% and 67.1%, respectively. In addition, the tensile fracture mechanism changes from brittle fracture for the alloy without modification to ductile fracture after modification. Modifying the morphology of Si phase and strengthening the matrix can effectively block the initiation and propagation of cracks, thus improving the strength of the hypereutectic Al-25Si alloy.

  8. Phase transformations behavior in a Cu-8.0Ni-1.8Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Q. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Li, Z., E-mail: lizhou6931@163.com [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China) and Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Wang, M.P. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Zhang, L.; Gong, S. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Xiao, Z. [Department of Engineering, University of Liverpool, Liverpool, L693 GH (United Kingdom); Pan, Z.Y. [Hunan Nonferrous Metals Holding Group Co., Ltd., Changsha, 410015 (China)

    2011-02-24

    Research highlights: > High solute concentrations Cu-Ni-Si alloy with super high strength and high conductivity has a good prospect for replacing Cu-Be alloys. At least four different kinds of precipitation products (DO{sub 22} ordered structure, {beta}-Ni{sub 3}Si precipitate, {delta}-Ni{sub 2}Si precipitate and {gamma}-Ni{sub 5}Si{sub 2} precipitate) have been observed in previous investigation. Therefore, the overall phase transformation behavior of Cu-Ni-Si alloy appears to be very complex. And most previous studies on the phase transformation usually investigated the precipitation process at only one temperature or at most a few temperatures, which is far away to establish a time-temperature-transformation (TTT) diagram for Cu-Ni-Si alloy. > The phase transformation behavior of Cu-8.0Ni-1.8Si alloy has been studied systematically at wide temperature range in this paper. The results we have gained are that: after solution treatment, followed by different conditions of isothermal treatment, DO{sub 22} ordering, discontinuous precipitation and continuous precipitation were observed in the alloy; discontinuous precipitates of {beta}-Ni{sub 3}Si phase appeared when the alloy isothermal treated at 550 deg. C for short time, which had not been reported by the previous Cu-Ni-Si system alloy's researchers in their papers; two kinds of precipitates of {beta}-Ni{sub 3}Si and {delta}-Ni{sub 2}Si were determined by the TEM characterization; the orientation relationship between the two kinds of precipitates and Cu-matrix is that: (1 1 0){sub Cu}//(1 1 0){sub {beta}}//(211-bar){sub {delta}}, [112-bar]{sub Cu}//[11-bar 2]{sub {beta}}//[3 2 4]{sub {delta}}; during overaging treatment, Cu-matrix, {beta}-Ni{sub 3}Si, {delta}-Ni{sub 2}Si and {delta}'-Ni{sub 2}Si were distinguished in the samples and the orientation relationship between the precipitates and Cu-matrix can be expressed as that: (0 2 2){sub Cu}//(0 2 2){sub {beta}}//(1 0 0){sub {delta}}, (02-bar 2){sub Cu

  9. Properties of amalgams made from lathe-cut, high Cu amalgam alloys.

    Science.gov (United States)

    Espevik, S

    1980-01-01

    Two alloys for dental amalgams made from lathe-cut powder with high Cu content have been developed. The alloys have been characterized with respect to physical properties and microstructure. The strongest amalgam exhibited minimal dimensional changes during setting and had low flow and creep values. It had the highest Cu content of the two amalgams investigated and no gamma 2 phase. The epsilon and eta' phases may dispersion-strenthen the amalgam which in compressive strength was comparable to the strongest amalgams available. A new mechanism for gamma 2 disappearance is suggested where Cu replaces Hg directly in the gamma 2 phase thus forming the eta' phase.

  10. Severe plastic deformation of copper and Al-Cu alloy using multiple channel-die compression

    International Nuclear Information System (INIS)

    Parimi, A.K.; Robi, P.S.; Dwivedy, S.K.

    2011-01-01

    Research highlights: → SPD of copper and Al-Cu alloy by multiple channel-die compression tests.→ Extensive grain refinement resulting in nano-sized grains after SPD. → Investigation of micro-structure using optical microscope and SEM. → Shear band formation as the failure mechanism in the two phase Al-Cu alloy. → Difficulty in obtaining SPD for Al-Cu alloy in this method. -- Abstract: Severe plastic deformation studies of copper and Al-Cu alloy by multiple channel-die compression tests were investigated. The materials were tested under plane strain condition by maintaining a constant strain rate of 0.001/s. Extensive grain refinement was observed resulting in nano-sized grains after severe plastic deformation with concomitant increase in flow stress and hardness. The microstructural investigation of the severely deformed materials was investigated using optical microscope and scanning electron microscope. Shear band formation was identified as the failure mechanism in the two phase Al-Cu alloy. The results indicate difficulty in obtaining severe plastic deformation for alloys having two phase micro-structure.

  11. Biocorrosion properties of antibacterial Ti-10Cu sintered alloy in several simulated biological solutions.

    Science.gov (United States)

    Liu, Cong; Zhang, Erlin

    2015-03-01

    Ti-10Cu sintered alloy has shown strong antibacterial properties against S. aureus and E. coli and good cell biocompatibility, which displays potential application in dental application. The corrosion behaviors of the alloy in five different simulated biological solutions have been investigated by electrochemical technology, surface observation, roughness measurement and immersion test. Five different simulated solutions were chosen to simulate oral condition, oral condition with F(-) ion, human body fluids with different pH values and blood system. It has been shown that Ti-10Cu alloy exhibits high corrosion rate in Saliva pH 3.5 solution and Saliva pH 6.8 + 0.2F solution but low corrosion rate in Hank's, Tyrode's and Saliva pH 6.8 solutions. The corrosion rate of Ti-10Cu alloy was in a order of Hank's, Tyrode's, Saliva pH 6.8, Saliva-pH 3.5 and Saliva pH 6.8 + 0.2F from slow to fast. All results indicated acid and F(-) containing conditions prompt the corrosion reaction of Ti-Cu alloy. It was suggested that the Cu ion release in the biological environments, especially in the acid and F(-) containing condition would lead to high antibacterial properties without any cell toxicity, displaying wide potential application of this alloy.

  12. The complex structure of liquid Cu{sub 6}Sn{sub 5} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qin Jingyu; Gu Tingkun; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Southern Campus, Jinan 250061 (China); Liu Hui [Shandong High Performance Computing Center, Shandong University, Southern Campus, Jinan 250061 (China)

    2009-04-15

    By applying ab initio molecular dynamics simulation to liquid Cu{sub 6}Sn{sub 5} alloy, the hetero-coordination tendency is discovered by Bathia-Thornton partial correlation functions and a chemical short-range parameter. However the local structural environment of Sn in l-Cu{sub 6}Sn{sub 5} alloy resembles that of liquid Sn by Voronoi analysis. A new feature, i.e. a subpeak in between the first and second peaks, is discovered by the present method which implies that topologically disordered {beta}-Sn-type structural units may exist in l-Cu{sub 6}Sn{sub 5} alloy. The local density states of electrons show that both Cu-Sn and Sn-Sn bonding exist in l-Cu{sub 6}Sn{sub 5} alloy. This work suggests that chemical short-range order between unlike atoms and self-coordination between Sn atoms coexists in l-Cu{sub 6}Sn{sub 5} alloy.

  13. 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

  14. Fusion and characterization of an alloy Cu-Zn-Al-Ni of nuclear interest

    International Nuclear Information System (INIS)

    Santana M, J.S.

    2003-01-01

    The present work is the result of the study of a non ferrous quatenary alloy of Cu-Zn-Al-Ni (Foundry 3), it was chosen of a series of alloys to obtain so much information of its microstructural properties like mechanical, evaluating them and comparing them with the previously obtained ternary alloys of Cu-AI-Ni (Foundry 1) and Cu-Zn-AI (Foundry 2) identified as alloys of memory effect and superalloys. These were carried out starting from the foundry of their pure elements of Cu, Zn, Al, Ni. When physically having the ingot of each alloy, different techniques were used for their characterization. The used techniques were through the metallographic analysis, by scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD), mechanical essays and Rockwell hardness. The non ferrous quaternary alloy Cu-Zn-AI-Ni by means of the metallographic analysis didn't show significant differences in their three sections (superficial, longitudinal and transverse) since result an homogeneous alloy at the same that the both ternaries. The grain size of the quaternary alloy is the finest while the ternary alloy of Cu-AI-Ni is the one that obtained the biggest grain size. Through MEB together with the analysis by EDS and the mapping of the elements that constitute each alloy, show that the three foundries were alloyed, moreover the presence of aggregates was also observed in the Foundries 2 and 3. These results by means of the analysis of XRD corroborate that these alloys have more of two elements. Relating the microstructural properties with those mechanical show us that as minor was the grain size, better they were his mechanical properties, in this case that of the quaternary alloy. With regard to the test of Rockwell hardness the Foundry 1 were the softest with the temper treatment, while that the Foundries 2 and 3 were the hardest with this same treatment, being still harder the Foundry 2 but with very little difference, for what great

  15. Unusual hardening behaviour in heavily cryo-rolled Cu-Al-Zn alloys during annealing treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y.L. [Faculty of Science, Kunming University of Science and Technology, Kunming 650500 (China); Ren, S.Y. [Ningbo Powerway Alloy Material Co., Ltd, Ningbo 315135 (China); Zeng, S.D. [Yunnan Institute of Measuring and Testing Technology, Kunming 650228 (China); Zhu, X.K., E-mail: xk_zhu@hotmail.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650500 (China)

    2016-04-06

    Three nanostructured Cu-Al-Zn alloys were produced via rolling at the liquid nitrogen temperature. The deformed Cu alloys were then annealed at 150–300 °C for 1 h. The two alloys with high solute content and thus with low stacking fault energy exhibit unusual annealing hardening, namely, an increase in hardness and strength and a decrease in tensile elongation after annealing at 150 and 200 °C. From X-ray diffraction (XRD) analysis and microstructural observations by transmission electron microscopy (TEM), it is found that microstrain and dislocation density decrease after annealing at 200 °C because of the recovery of dislocations and the lattice parameter decreases due to solute segregation. Meanwhile, the twin density of the two Cu alloys increases and grain size remains basically unchanged. It is shown that the formation of annealing twins and stacking faults and the segregation of solute atoms may be the main causes of unusual annealing hardening.

  16. Non-isothermal precipitation behaviors of Al-Mg-Si-Cu alloys with different Zn contents

    International Nuclear Information System (INIS)

    Guo, M.X.; Zhang, Y.; Zhang, X.K.; Zhang, J.S.; Zhuang, L.Z.

    2016-01-01

    The non-isothermal precipitation behaviors of Al–Mg–Si–Cu alloys with different Zn contents were investigated by differential scanning calorimetry (DSC) analysis, hardness measurement and high resolution transmission electron microscope characterization. The results show that Zn addition has a significant effect on the GP zone dissolution and precipitation of Al-Mg-Si-Cu alloys. And their activation energies change with the changes of Zn content and aging conditions. Precipitation kinetics can be improved by adding 0.5 wt% or 3.0 wt%Zn, while be suppressed after adding 1.5 wt%Zn. The Mg-Si precipitates (GP zones and β″) are still the main precipitates in the Al-Mg-Si-Cu alloys after heated up to 250 °C, and no Mg-Zn precipitates are observed in the Zn-added alloy due to the occurrence of Mg-Zn precipitates reversion. The measured age-hardening responses of the alloys are corresponding to the predicted results by the established precipitation kinetic equations. Additionally, a double-hump phenomenon of hardness appears in the artificial aging of pre-aged alloy with 3.0 wt% Zn addition, which resulted from the formation of pre-β″ and β″ precipitates. Finally, the precipitation mechanism of Al-Mg-Si-Cu alloys with different Zn contents was proposed based on the microstructure evolution and interaction forces between Mg, Si and Zn atoms.

  17. 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.

  18. The Mechanical Properties of AlSi17Cu5 Cast Alloy after Overheating and Modification of CuP Master Alloy

    Directory of Open Access Journals (Sweden)

    Piątkowski J.

    2013-09-01

    Full Text Available The paper presents the results of studies on the effect of the AlSi17Cu5 alloy overheating to atemperature of 920°C and modification with phosphorus (CuP10 on the resultingmechanical (HB, Rm, R0.2 and plastic (A5 and Z properties. It has been shown that, so-called, "timethermal treatment" (TTT of an alloy in the liquid state, consisting inoverheating the metal to about 250°C above Tliq,holding at this temperature by 30 minutes improvesthe mechanical properties. It has also been found that overheating of alloy above Tliq.enhances the process of modification, resulting in the formation of fine-grain structure. The primary silicon crystals uniformly distributed in the eutectic and characteristics ofthe α(Al solution supersaturated with alloying elements present in the starting alloy composition (Cu, Fe provide not only an increase of strength at ambient temperature but also at elevated temperature (250°C.

  19. A diffuse neutron scattering study of clustering kinetics in Cu-Ni alloys

    International Nuclear Information System (INIS)

    Vrijen, J.; Radelaar, S.; Schwahn, D.

    1977-01-01

    Diffuse scattering of thermal neutrons was used to investigate the kinetics of clustering in Cu-Ni alloys. In order to optimize the experimental conditions the isotopes 65 Cu and 62 Ni were alloyed. The time evolution of the diffuse scattered intensity at 400 0 C has been measured for eight Cu-Ni alloys, varying in composition between 30 and 80 at. pour cent Ni. The relaxation of the so called null matrix, containing 56.5 at. pour cent Ni has also been investigated at 320, 340, 425 and 450 0 C. Using Cook's model from all these measurements information has been deduced about diffusion at low temperatures and about thermodynamic properties of the Cu-Ni system. It turns out that Cook's model is not sufficiently detailed for an accurate description of the initial stages of these relaxations

  20. Preparation of a high strength Al-Cu-Mg alloy by mechanical alloying and press-forming

    Energy Technology Data Exchange (ETDEWEB)

    Tang Huaguo [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Cheng Zhiqiang [College of Resources and Environment, Jilin Agricultural University, Changchun 130118 (China); Liu Jianwei [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Ma Xianfeng, E-mail: xfma@ciac.jl.cn [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer A high strength aluminum alloy of Al-2 wt.%Mg-2 wt.%Cu has been prepared by mechanical alloying and press-forming. Black-Right-Pointing-Pointer The alloy only consists of solid solution {alpha}-Al. Black-Right-Pointing-Pointer The grains size of {alpha}-Al was about 300 nm-5 {mu}m. Black-Right-Pointing-Pointer The solid solution strengthening and the grain refinement strengthening are the main reasons for such a high strength. - Abstract: A high strength aluminum alloy, with the ratio of 96 wt.%Al-2 wt.%Mg-2 wt.%Cu, has been prepared by mechanical alloying and press-forming. The alloy exhibited a high tensile strength of 780 MPa and a high microhardness of 180 HV. X-ray diffraction characterizations confirmed that the alloy only consists of a solid solution {alpha}-Al. Microstructure characterizations revealed that the grain size of {alpha}-Al was about 300 nm-5 {mu}m. The solid solution strengthening and the grain refinement strengthening were considered to be the reason for such a high strength.

  1. 25th anniversary article: Understanding the lithiation of silicon and other alloying anodes for lithium-ion batteries.

    Science.gov (United States)

    McDowell, Matthew T; Lee, Seok Woo; Nix, William D; Cui, Yi

    2013-09-25

    Alloying anodes such as silicon are promising electrode materials for next-generation high energy density lithium-ion batteries because of their ability to reversibly incorporate a high concentration of Li atoms. However, alloying anodes usually exhibit a short cycle life due to the extreme volumetric and structural changes that occur during lithium insertion/extraction; these transformations cause mechanical fracture and exacerbate side reactions. To solve these problems, there has recently been significant attention devoted to creating silicon nanostructures that can accommodate the lithiation-induced strain and thus exhibit high Coulombic efficiency and long cycle life. In parallel, many experiments and simulations have been conducted in an effort to understand the details of volumetric expansion, fracture, mechanical stress evolution, and structural changes in silicon nanostructures. The fundamental materials knowledge gained from these studies has provided guidance for designing optimized Si electrode structures and has also shed light on the factors that control large-volume change solid-state reactions. In this paper, we review various fundamental studies that have been conducted to understand structural and volumetric changes, stress evolution, mechanical properties, and fracture behavior of nanostructured Si anodes for lithium-ion batteries and compare the reaction process of Si to other novel anode materials. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.D., E-mail: fanxd@seu.edu.cn; Shen, B.L., E-mail: blshen@seu.edu.cn

    2015-07-01

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe{sub 86}B{sub 7}C{sub 7} alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe{sub 3}C and α-Fe phase impedes the devitrification. • Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity.

  3. Phase transformation and microstructure study of the as-cast Cu-rich Cu-Al-Mn ternary alloys

    Directory of Open Access Journals (Sweden)

    Holjevac-Grgurić T.

    2017-01-01

    Full Text Available Four Cu-rich alloys from the ternary Cu-Al-Mn system were prepared in the electric-arc furnace and casted in cylindrical moulds with dimensions: f=8 mm and length 12 mm. Microstructural investigations of the prepared samples were performed by using optical microscopy (OM and scanning electron microscopy, equipped by energy dispersive spectroscopy (SEM-EDS. Assignation of crystalline phases was confirmed by XRD analysis. Phase transition temperatures were determined using simultaneous thermal analyzer STA DSC/TG. Phase equilibria calculation of the ternary Cu-Al-Mn system was performed using optimized thermodynamic parameters from literature. Microstructure and phase transitions of the prepared as-cast alloys were investigated and experimental results were compared with the results of thermodynamic calculations.

  4. 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.

  5. Effect of Recrystallization and Natural Aging on Mechanical Properties of Al-Zn-Mg-Cu-Sc Alloys

    International Nuclear Information System (INIS)

    Yu, Min Kyu; Hong, Soon Hyung; Kwon, Oh Yeol; Lee, Yong Yeon

    2015-01-01

    In this study, the recrystallization volume fraction of the Al-Zn-Mg-Cu-Sc alloy after solid solution heat treatment varied with different temperatures (445℃ - 465℃). The highest elongation of the Al-Zn-Mg-Cu-Sc alloy was obtained at 465℃. Further, the hardness and strength of the solid solution heat treated Al-Zn-Mg-Cu-Sc alloy increased at room temperature due to G.P zone precipitates. The results confirmed that we can obtain advanced mechanical properties for the Al-Zn-Mg-Cu-Sc alloy from solid solution heat treatment and natural aging.

  6. Crystallization-induced plasticity of Cu-Zr containing bulk amorphous alloys

    International Nuclear Information System (INIS)

    Lee, Seok-Woo; Huh, Moo-Young; Fleury, Eric; Lee, Jae-Chul

    2006-01-01

    This study examined the parameter governing the plasticity observed in various Cu-Zr containing monolithic amorphous alloys. All the alloys were fully amorphous in their as-cast condition but exhibited different plastic strains. Microscopic observations of the quasi-statically compressed alloys showed abundant nanocrystallites in the amorphous matrices in the alloys that exhibited pronounced plasticity. On the other hand, insignificant changes in the microstructure were observed in the alloy that did not show plasticity. The mechanism for the formation of these deformation-induced nanocrystallites was examined from the viewpoints of thermodynamics and kinetics. The role of the deformation-induced nanocrystallites on the plasticity of the amorphous alloy was examined using high-resolution transmission electron microscopy. The results demonstrate that compressive loading facilitates nanocrystallization in monolithic Cu-Zr containing amorphous alloys, resulting in plasticity. The parameter governing the plasticity in these monolithic Cu-Zr containing amorphous alloys lies in the activation energy for the overall crystallization process

  7. Enhanced bake-hardening response of an Al–Mg–Si–Cu alloy with Zn addition

    Energy Technology Data Exchange (ETDEWEB)

    Guo, M.X., E-mail: mingxingguo@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Sha, G., E-mail: gang.sha@njust.edu.cn [School of Materials Science and Engineering, Nanjing University of Science and Technology, Jiangsu 210094 (China); Cao, L.Y. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Liu, W.Q. [Key Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Zhang, J.S.; Zhuang, L.Z. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-07-15

    This study reports that Zn addition greatly enhances the bake-hardening response of an Al–Mg–Si–Cu alloy. The pre-aged alloy exhibits a high strength increment of 135 MPa after paint baking. Differential scanning calorimetry, atom probe tomography and high-resolution transmission electron microscopy reveal that Zn addition and pre-aging have significant effects on the solute nanostructure formation. Zn atoms partition into solute clusters/GP zones, and reduce the activation energy of β” precipitation in the alloy. - Highlights: • Zn addition can improve the bake-hardening response of an Al–Mg–Si–Cu alloy. • Zn addition can stabilize the solute clusters/GP zones from dissolution. • Zn addition can reduce the size of clusters formed in the pre-aging treatment. • Zn partitioned into solute clusters/GP zones and β” in the Zn-containing Al alloy.

  8. Mechanical properties of Fe-Mn-Cu-Al alloy systems and optimization of their composition

    International Nuclear Information System (INIS)

    Tkachenko, I.F.; Baranov, A.A.

    1981-01-01

    Studied is the separate and combined effect of Cu and Al on mechanical properties of the Fe-Mn-Al-Cu system alloys using a simplex- lattice method of experiment planning. Heat treated specimens in the form of plates have been subjected to mechanical tests. It is shown that mechanical properties of studied alloys change sufficiently in the result of tempering in heterogeneous (α+γ) region. Studied alloys have the most favourable conbination of characteristics of strength, plasticity and impact strength after tempering at 630 deg C during 2 hours. Diagrams are obtained which characterizes dependence of mechanical properties of alloys on their composition. They permit to select optimum compositions of alloys with the necessary combination of strength, plasticity and impact strength [ru

  9. Magnetic Susceptibility of liquid Gd-NM (NM = Cu, Ga, Ge alloys

    Directory of Open Access Journals (Sweden)

    Shimakura Hironori

    2017-01-01

    Full Text Available For rare earth alloys, the indirect interaction of RKKY is at work between rare-earth atoms. Therefore, the magnetism of them depends on the number of conduction electrons and the distance between rare-earth metals. In this work, to reveal the relationship between the number of conduction electrons and magnetic property of rare earth metal alloys, magnetic susceptibility measurements for liquid Gd-NM (NM = Cu, Ga, Ge was performed by Faraday method. As the results, it was observed that the sign of paramagnetic Curie temperature of Cu-Gd alloys are positive at all composition, while Ga-Gd and Ge-Gd alloys show negative paramagnetic Curie temperature at certain composition. Moreover, it was indicated when the alloy at certain composition shows highest melting temperature, it has the lowest paramagnetic Curie temperature.

  10. Growth and characterization of Cu2ZnSnS4 nanostructures using anodized aluminum as the growth mask

    Science.gov (United States)

    Chan, C. P.; Chen, Z.; Lam, H.; Surya, C.

    2009-08-01

    In this paper we report the growth and characterization of Cu2ZnSnS4 (CZTS) nanostructures by co-electrodeposition technique using CuCl2, SnCl2 and ZnCl2 as sources and choline-based ionic liquid (IL) as the electrolyte. X-ray diffraction analysis of CZTS thin films grown by this technique indicated that the films have a kesterite structure with preferred grain orientation along (112). It is found that the energy bandgap of the material is about 1.49eV and the optical absorption coefficient is in the order of 104cm-1. Anodized aluminum oxide (AAO) was used as the growth mask for the growth of the nanostructures. Anodization of the aluminum foil was carried out in phosphoric acid solution at 1°C and a potential of 40 to 100V was applied. Sulfurization of the rods was performed in elemental sulfur vapor at 450°C for four hours using N2 as the ambient gas. Experimental results show that nanotubes were formed using the technique and the diameter can be well controlled by varying the applied potential in the anodization process. Electron diffraction experiments show that a mixture of single- and poly-crystalline nanostructures was found.

  11. Development the Mechanical Properties of (AL-Li-Cu Alloy

    Directory of Open Access Journals (Sweden)

    Ihsan Kadhom AlNaimi

    2017-11-01

    Full Text Available The aim of this research is to develop mechanical properties of a new aluminium-lithium-copper alloy. This alloy prepared under control atmosphere by casting in a permanent metal mould. The microstructure was examined and mechanical properties were tested before and after heat treatment to study the influence of heat treatment on its mechanical properties including; modulus of elasticity, tensile strength, impact, and fatigue. The results showed that the modulus of elasticity of the prepared alloy is higher than standard alloy about 2%. While the alloy that heat treated for 6 h and cooled in water, then showed a higher ultimate tensile stress comparing with as-cast alloy. The homogenous heat treatment gives best fatigue behaviour comparing with as-cast and other heat treatment alloys. Also, the impact test illustrates that the homogeneous heat treatment alloy gives the highest value.

  12. Cermet anode with continuously dispersed alloy phase and process for making

    Science.gov (United States)

    Marschman, Steven C.; Davis, Norman C.

    1989-01-01

    Cermet electrode compositions and methods for making are disclosed which comprise NiO--NiFe.sub.2 O.sub.4 --Cu--Ni. Addition of an effective amount of a metallic catalyst/reactant to a composition of a nickel/iron/oxide, NiO, copper, and nickel produces a stable electrode having significantly increased electrical conductivity. The metallic catalyst functions to disperse the copper and nickel as an alloy continuously throughout the oxide phase of the cermet to render the electrode compositon more highly electrically conductive than were the third metal not present in the base composition. The third metal is preferably added to the base composition as elemental metal and includes aluminum, magnesium, sodium and gallium. The elemental metal is converted to a metal oxide during the sintering process.

  13. Increasing Wear Resistance of Titanium Alloys by Anode Plasma Electrolytic Saturation with Interstitial Elements

    Science.gov (United States)

    Belkin, P. N.; Kusmanov, S. A.; Dyakov, I. G.; Silkin, S. A.; Smirnov, A. A.

    2017-05-01

    In our previous studies, we have shown that anode plasma electrolytic saturation of titanium alloys with nitrogen and carbon can improve their tribological properties. Obtained structure containing oxide layer and solid solution of diffused element in titanium promotes the enhancement of running-in ability and the decrease in the wear rate in some special cases. In this paper, further investigations are reported regarding the tribological properties of alpha- and beta-titanium alloys in wear test against hardened steel (50 HRC) disk using pin-on-disk geometry and balls of Al2O3 (6.25 mm in diameter) or bearing steel (9.6 mm in diameter) with ball-on-plate one and normal load from 5 to 209 N. Reproducible results were obtained under testing samples treated by means of the plasma electrolytic nitriding (PEN) with the mechanical removal of the oxide layer. Friction coefficient of nitrided samples is 0.5-0.9 which is somewhat higher than that for untreated one (0.48-0.75) during dry sliding against Al2O3 ball. An increase in the sliding speed results in the polishing of nitrided samples and reduction of their wear rate by 60 times. This result is obtained for 5 min at 850 °C using PEN in electrolyte containing 5 wt.% ammonia and 10 wt.% ammonium chloride followed by quenching in solution. Optical microscope was employed to assist in the evaluation of the wear behavior. Sizes of wear tracks were measured by profilometer TR200.

  14. Effects of Alloying Elements on Room and High Temperature Tensile Properties of Al-Si Cu-Mg Base Alloys =

    Science.gov (United States)

    Alyaldin, Loay

    In recent years, aluminum and aluminum alloys have been widely used in automotive and aerospace industries. Among the most commonly used cast aluminum alloys are those belonging to the Al-Si system. Due to their mechanical properties, light weight, excellent castability and corrosion resistance, these alloys are primarily used in engineering and in automotive applications. The more aluminum is used in the production of a vehicle, the less the weight of the vehicle, and the less fuel it consumes, thereby reducing the amount of harmful emissions into the atmosphere. The principal alloying elements in Al-Si alloys, in addition to silicon, are magnesium and copper which, through the formation of Al2Cu and Mg2Si precipitates, improve the alloy strength via precipitation hardening following heat treatment. However, most Al-Si alloys are not suitable for high temperature applications because their tensile and fatigue strengths are not as high as desired in the temperature range 230-350°C, which are the temperatures that are often attained in automotive engine components under actual service conditions. The main challenge lies in the fact that the strength of heat-treatable cast aluminum alloys decreases at temperatures above 200°C. The strength of alloys under high temperature conditions is improved by obtaining a microstructure containing thermally stable and coarsening-resistant intermetallics, which may be achieved with the addition of Ni. Zr and Sc. Nickel leads to the formation of nickel aluminide Al3Ni and Al 9FeNi in the presence of iron, while zirconium forms Al3Zr. These intermetallics improve the high temperature strength of Al-Si alloys. Some interesting improvements have been achieved by modifying the composition of the base alloy with additions of Mn, resulting in an increase in strength and ductility at both room and high temperatures. Al-Si-Cu-Mg alloys such as the 354 (Al-9wt%Si-1.8wt%Cu-0.5wt%Mg) alloys show a greater response to heat treatment as a

  15. Deposition of CuIn(Se,S)2 thin films by sulfurization of selenized Cu/In alloys

    International Nuclear Information System (INIS)

    Sheppard, C.J.; Alberts, V.; Bekker, W.J.

    2004-01-01

    The relatively small band gap values (close to 1eV) of CuInSe 2 thin films limits the conversion efficiencies of completed CuInSe 2 /CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to increase the band gap by substituting indium with gallium. In this study, sputtered copper-indium alloys were exposed to a H 2 Se/Ar atmosphere under defined conditions in order to produce partially reacted CuInSe 2 structures. These films were subsequently exposed to a H 2 S/Ar atmosphere to produce monophasic CuIn(Se, S) 2 quaternary alloys. The homogeneous incorporation of S into CuInSe 2 led to a systematic shift in the lattice parameters and band gap of the ab- sorber films. From these studies optimum selenization/sulfurization conditions were determined for the deposition of homogeneous CuIn(Se,S) 2 thin films with an optimum band gap values between 1.15 and 1.2 eV. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Metastable Phase Separation and Concomitant Solute Redistribution of Liquid Fe-Cu-Sn Ternary Alloy

    International Nuclear Information System (INIS)

    Xiao-Mei, Zhang; Wei-Li, Wang; Ying, Ruan; Bing-Bo, Wei

    2010-01-01

    Liquid Fe-Cu-Sn ternary alloys with lower Sn contents are usually assumed to display a peritectic-type solidification process under equilibrium condition. Here we show that liquid Fe 47.5 Cu 47.5 Sn 5 ternary alloy exhibits a metastable immiscibility gap in the undercooling range of 51–329 K (0.19T L ). Macroscopic phase separation occurs once undercooling exceeds 196 K and causes the formation of a floating Fe-rich zone and a descending Cu-rich zone. Solute redistribution induces the depletion of Sn concentration in the Fe-rich zone and its enrichment in the Cu-rich zone. The primary Fe phase grows dendritically and its growth velocity increases with undercooling until the appearance of notable macrosegregation, but will decrease if undercooling further increases beyond 236 K. The microsegregation degrees of both solutes in Fe and Cu phases vary only slightly with undercooling. (condensed matter: structure, mechanical and thermal properties)

  17. Application of single pan thermal analysis to Cu-Sn peritectic alloys

    International Nuclear Information System (INIS)

    Kohler, F.; Campanella, T.; Nakanishi, S.; Rappaz, M.

    2008-01-01

    Single pan thermal analyses (SPTA) have been performed on Cu-14.5 wt.% Sn, Cu-21.3 wt.% Sn and Cu-26.8 wt.% Sn peritectic alloys. For this purpose, a SPTA assembly has been built and calibrated. As the latent heat is a function of temperature and composition during solidification of alloys, a new heat flow model coupled to a Cu-Sn thermodynamic database has been defined for the calculation of the corresponding evolutions of the solid mass fraction, f s (T). To verify the accuracy of this model, a close comparison with a microsegregation model that includes back-diffusion in the primary α-solid phase has also been conducted successfully. The thermal analyses have finally shown that the Cu-Sn phase diagram recently assessed in the review of Liu et al. is the most reliable

  18. Alloying of Yb-Cu and Yb-Ag utilizing liquid ammonia metal solutions of ytterbium

    International Nuclear Information System (INIS)

    Imamura, H.; Yoshimura, T.; Sakata, Y.

    2003-01-01

    In the course of the studies on preparation of novel compounds using the dissolution of Eu or Yb metals in liquid ammonia, the formation of Yb-Cu and Yb-Ag intermetallic films has been found. When Cu or Ag metal powders were placed in a reactor containing a solution of Yb metal in liquid ammonia, the dissolved Yb readily react with the Cu or Ag metal particles to form surface alloy compounds. X-ray diffraction of Yb-Cu showed that upon thermal treatment above 673 K, the Yb metal deposited on the Cu particles reacted together to be transformed into the YbCu 6.5 intermetallic compound. A characteristic endothermic peak at 749 K, due to alloying of Yb-Cu, was observed by the differential scanning calorimeter measurements. By use of the high reactivity of liquid ammonia metal solutions of ytterbium, it was found that the ytterbium intermetallic films were readily formed under mild conditions. Yb-Cu and Yb-Ag exhibited enhanced catalytic activity for the hydrogenation of ethene as a result of alloying

  19. Sintering of powders obtained by mechanical alloying of Cu-1.2 Al w%, Cu-2.3 Ti w% and Cu-2.7 V w%

    International Nuclear Information System (INIS)

    Rivas, C; Sepulveda, A; Zuniga, A; Donoso, E; Palma, R

    2008-01-01

    This work studies the effect of compacting pressure, temperature and sintering time on density and microstructure after sintering mechanically alloyed powders of Cu-1.2 Al w%, Cu- 2.3 Ti w% and Cu-2.7 V w%. The alloys were manufactured from elementary powders of Cu, Ti, Al and V, by reactive milling. The powders were compacted and sintered under reducer atmosphere. For each alloy, the final density and resulting microstructure of 8 different compacting and sintering conditions were studied, where the following parameters were considered: (1) Compacting pressure (200 MPa and 400 MPa), (2) Sintering temperature (850 o C and 950 o C), (3) Sintering time (1h and 4h). Adjustments were made using lineal regression to describe the effect of the variation of pressure, temperature and time on the density of the materials obtained, and the morphology of the residual porosity was described by observation under an optic microscope. The final maximum density obtained was, in ascending order: Cu-V, 66% of the theoretical density, TD; Cu-Ti, 65% TD and Cu-Al, 77% TD. The reactive milling process produced flake-shaped particles, hardened by deformation, which made the alloys have a final density that was much less than the sintered pure copper (density 87% TD). This is because the hardened powder resists deformation during compacting, which creates less points of contact between particles, slows down sintering, and yields a lower density. The alloying element influenced the size of the particle obtained during the milling, which is attributed to the different milling mediums (toluene for Ti and V, methanol for Al) and to the different hardness of each ceramic when forming in the copper during milling. The bigger the particle size, the greater the green density, the lesser the densification, and the greater the final density, in accordance with the theory. For the three alloys, the increased compacting pressure gives greater green density, greater densification and a final greater

  20. The natural aging and precipitation hardening behaviour of Al-Mg-Si-Cu alloys with different Mg/Si ratios and Cu additions

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Lipeng [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 China (China); Jia, Zhihong, E-mail: zhihongjia@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 China (China); Zhang, Zhiqing; Sanders, Robert E.; Liu, Qing [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 China (China); Yang, Guang [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Centre for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049 (China)

    2015-03-11

    The natural aging and artificial aging behaviours of Al-Mg-Si-Cu alloys with different Mg/Si ratios and Cu additions were investigated using Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterisation. Excess Si and Cu additions enhanced the alloy hardening ability during natural (NA) and artificial aging (AA). Alloys with low Cu and high Si contents exhibited higher precipitation hardening than alloys rich in Mg during artificial aging. In contrast, the alloys with high amounts of Cu were less dependent on the Mg/Si ratio during precipitation hardening due to their similar aging kinetics. The main precipitate phases that contributed to the peak-aging hardness were the L, Q′ and β″ phases. In the over-aging conditions, the alloys rich in Mg and Cu had finer and more numerous precipitates than their Si-rich equivalents due to the preferential precipitation of the L phase. The combination of excess Mg and high Cu resulted in an alloy with a relatively low hardness in T4 temper and a relatively higher hardness after the paint baking cycle. Thus, this alloy has good potential for use in auto body panel applications.

  1. Initial stages of AZ91 Mg alloy micro-arc anodizing: Growth mechanisms and effect on the corrosion resistance

    International Nuclear Information System (INIS)

    Veys-Renaux, Delphine; Rocca, Emmanuel; Martin, Julien; Henrion, Gérard

    2014-01-01

    Graphical abstract: - Highlights: • The dielectric breakdown occurs for a specific value of capacitance. • Before breakdown, Si is incorporated to the anodic film under MgSiO 3 form. • After breakdown, Si is incorporated to the anodic film also under Mg 2 SiO 4 form. • The presence of Mg 2 SiO 4 in the anodic film provides good corrosion resistance due to sealing of the porosities. - Abstract: In the framework of the new ecological regulations, micro-arc oxidation (MAO) appears as an alternative to usual processes in the field of corrosion protection of Mg alloys. In this work, the initial stages of anodic layer growth in KOH-based electrolytes are studied up to and beyond the initiation of the micro-arc regime. The properties of the first anodized film preceding the occurrence of the dielectric breakdown (corresponding to the start of the micro-arc regime) are mainly determined by the incorporation of additives (fluorides or silicates) in the film, as shown by in situ electrochemical measurements. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and micro-Raman spectroscopy reveal both the change of morphology and chemical state of silicate and fluoride in the anodized layer before and after the micro-arc regime. In terms of electrochemical behaviour, investigated by stationary methods and electrochemical impedance spectroscopy (EIS) in reference corrosive water, the anodic film grown in the silicate medium provides the best corrosion resistance thanks to a thick layer containing Mg 2 SiO 4 , whose degradation products seal the porosities of the coating

  2. Research on high-temperature compression and creep behavior of porous Cu–Ni–Cr alloy for molten carbonate fuel cell anodes

    Directory of Open Access Journals (Sweden)

    Li W.

    2015-06-01

    Full Text Available The effect of porosity on high temperature compression and creep behavior of porous Cu alloy for the new molten carbonate fuel cell anodes was examined. Optical microscopy and scanning electron microscopy were used to investigate and analyze the details of the microstructure and surface deformation. Compression creep tests were utilized to evaluate the mechanical properties of the alloy at 650 °C. The compression strength, elastic modulus, and yield stress all increased with the decrease in porosity. Under the same creep stress, the materials with higher porosity exhibited inferior creep resistance and higher steadystate creep rate. The creep behavior has been classified in terms of two stages. The first stage relates to grain rearrangement which results from the destruction of large pores by the applied load. In the second stage, small pores are collapsed by a subsequent sintering process under the load. The main deformation mechanism consists in that several deformation bands generate sequentially under the perpendicular loading, and in these deformation bands the pores are deformed by flattering and collapsing sequentially. On the other hand, the shape of a pore has a severe influence on the creep resistance of the material, i.e. every increase of pore size corresponds to a decrease in creep resistance.

  3. A three-dimensional hierarchical nanoporous PdCu alloy for enhanced electrocatalysis and biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Liu Aihua [Laboratory for Nanobioelectronics and Biosensors, Qingdao Institute of Bioenergy and Bioprocess Technology, and Key Laboratory for Biofuels, Chinese Academy of Sciences, Qingdao 266101 (China); Geng Haoran [School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Xu Caixia, E-mail: chm_xucx@ujn.edu.cn [School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Qiu Huajun, E-mail: qiuhuajun@gmail.com [Laboratory for Nanobioelectronics and Biosensors, Qingdao Institute of Bioenergy and Bioprocess Technology, and Key Laboratory for Biofuels, Chinese Academy of Sciences, Qingdao 266101 (China)

    2011-10-10

    Highlights: {yields} Nanotubular mesoporous PdCu (NM-PdCu) alloy is facilely fabricated via one-step metal replacement reaction between nanoporous Cu and H{sub 2}PdCl{sub 4}. {yields} The NM-PdCu exhibits remarkably improved structure stability and electrocatalytic activity towards formic acid and hydrogen peroxide oxidation compared with NP-Pd. {yields} When coupled with GOx, the GOx/NM-PdCu electrode can be used for sensitive detection of glucose over a wide concentration range. - Abstract: Nanoporous copper (NPC) obtained by dealloying CuAl alloy is used as both three-dimensional template and reducing agent for the fabrication of nanoporous PdCu alloy with hollow ligaments by a simple galvanic replacement reaction with H{sub 2}PdCl{sub 4} aqueous solution. Electron microscopy and X-ray diffraction characterizations demonstrate that after the replacement reaction, the ligaments become hollow tubular structure and the ligament shell is also comprised of small pores and nanoparticles with a typical size of {approx}4 nm (third order porosity). The as-prepared nanotubular mesoporous PdCu alloy (NM-PdCu) structure exhibits remarkably improved electrocatalytic activity towards the oxidation of formic acid and H{sub 2}O{sub 2} compared with nanoporous Pd (NP-Pd), and can be used for sensitive electrochemical sensing applications. After coupled with glucose oxidase (GOx), the enzyme modified NM-PdCu electrode can sensitively detect glucose over a wide linear range (0.5-20 mM).

  4. Grain refining of Al-4.5Cu alloy by adding an Al-30TiC master alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kazuaki [Toyota Motor Corp., Shizuoka (Japan). Materials Engineering Div. III; Flemings, M.C. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

    1998-06-01

    A particulate Al-30 wt pct TiC composite was employed as a grain refiner for the Al-4.5 wt pct Cu alloy. The composite contains submicron TiC particles. The addition of the TiC grain refiner to the metal alloy in the amount of 0.1 Ti wt pct effected a remarkable reduction in the average grain size in Al-4.5 wt pct Cu alloy castings. With the content of over 0.2 Ti wt pct, the grain refiner maintained its refining effectiveness even after a 3,600-second holding time at 973 K. The TiC particles in the resulting castings were free of interfacial phases. It is concluded that the TiC are the nucleating agents and that they are resistant to the fading effect encountered with most grain refiners.

  5. Enhancing pitting corrosion resistance of AlxCrFe1.5MnNi0.5 high-entropy alloys by anodic treatment in sulfuric acid

    International Nuclear Information System (INIS)

    Lee, C.P.; Chen, Y.Y.; Hsu, C.Y.; Yeh, J.W.; Shih, H.C.

    2008-01-01

    High-entropy alloys are a newly developed family of multi-component alloys that comprise various major alloying elements. Each element in the alloy system is present in between 5 and 35 at.%. The crystal structures and physical properties of high-entropy alloys differ completely from those of conventional alloys. The electrochemical impedance spectra (EIS) of the Al x CrFe 1.5 MnNi 0.5 (x = 0, 0.3, 0.5) alloys, obtained in 0.1 M HCl solution, clearly revealed that the corrosion resistance values were determined to increase from 21 to 34 Ωcm 2 as the aluminum content increased from 0 to 0.5 mol, and were markedly lower than that of 304 stainless steel (243 Ωcm 2 ). At passive potential, the corresponding current declined with the anodizing time accounting, causing passivity by the growth of the multi-component anodized film in H 2 SO 4 solution. X-ray photoelectron spectroscopy (XPS) analyses revealed that the surface of anodized Al 0.3 CrFe 1.5 MnNi 0.5 alloy formed aluminum and chromium oxide film which was the main passivating compound on the alloy. This anodic treatment increased the corrosion resistance in the EIS measurements of the CrFe 1.5 MnNi 0.5 and Al 0.3 CrFe 1.5 MnNi 0.5 alloys by two orders of magnitude. Accordingly, the anodic treatment of the Al x CrFe 1.5 MnNi 0.5 alloys optimized their surface structures and minimized their susceptibility to pitting corrosion

  6. Experimental Liquidus Studies of the Pb-Cu-Si-O System in Equilibrium with Metallic Pb-Cu Alloys

    Science.gov (United States)

    Shevchenko, M.; Nicol, S.; Hayes, P. C.; Jak, E.

    2018-03-01

    Phase equilibria of the Pb-Cu-Si-O system have been investigated in the temperature range from 1073 K to 1673 K (800 °C to 1400 °C) for oxide liquid (slag) in equilibrium with solid Cu metal and/or liquid Pb-Cu alloy, and solid oxide phases: (a) quartz or tridymite (SiO2) and (b) cuprite (Cu2O). High-temperature equilibration on silica or copper substrates was performed, followed by quenching, and direct measurement of Pb, Cu, and Si concentrations in the liquid and solid phases using the electron probe X-ray microanalysis has been employed to accurately characterize the system in equilibrium with Cu or Pb-Cu metal. All results are projected onto the PbO-"CuO0.5"-SiO2 plane for presentation purposes. The present study is the first-ever systematic investigation of this system to describe the slag liquidus temperatures in the silica and cuprite primary phase fields.

  7. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    Science.gov (United States)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  8. Synthesis of FeSiBPNbCu nanocrystalline soft-magnetic alloys with high saturation magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zongzhen [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Wang, Anding; Chang, Chuntao [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 519 Zhuangshi Road, Zhenhai District, Ningbo, Zhejiang 315201 (China); Wang, Yanguo [Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing 100080 (China); Dong, Bangshao [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Zhou, Shaoxiong, E-mail: sxzhou@atmcn.com [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China)

    2014-10-25

    Highlights: • Thermal stability of the FeSiBPNbCu alloys is strongly dependent on the Fe content. • The FeSiBPNbCu alloys with high Fe content exhibit good soft magnetic properties. • The coexistence of Cu, P and Nb leads to the excellent soft magnetic properties. - Abstract: A series of [Fe{sub 0.76+x}(Si{sub 0.4}B{sub 0.4}P{sub 0.2}){sub 0.24−x}]{sub 98.25}Nb{sub 1}Cu{sub 0.75} (x = 0–0.08) nanocrystalline soft-magnetic alloys with high saturation magnetization were synthesized by adjusting Fe content and improving the crystallization behavior, soft-magnetic properties and microstructure. It is found that the temperature interval between the two crystallization peaks is significantly enlarged from 50 to 180 °C when the Fe content of the alloys increases from x = 0 to x = 0.08, which greatly expands the optimum annealing temperature range. The alloys with higher Fe content are prone to form more uniform nanocomposite microstructure with better thermal stability and soft magnetic properties. The Fe-rich FeSiBPNbCu nanocrystalline alloys with x = 0.08 exhibit excellent soft-magnetic properties, including the high saturation magnetic flux density of up to 1.74 T, low coercivity of about 3.3 A/m and high effective permeability of more than 2.2 × 10{sup 4} at 1 kHz under a field of 1 A/m. The combination of excellent soft-magnetic properties, low cost and good productivity makes the FeSiBPNbCu alloys to be a kind of promising soft-magnetic materials for electrical and electronic industry applications.

  9. Newly developed EMF cell with zirconia solid electrolyte for measurement of low oxygen potentials in liquid Cu-Cr and Cu-Zr alloys

    Directory of Open Access Journals (Sweden)

    Katayama I.

    2012-01-01

    Full Text Available In order to measure the very low oxygen potential by use of stabilized zirconia solid electrolyte emf method, a new cell construction was devised. The idea was based on Janke but a zirconia rod was used instead of the zirconia crucible which contacts liquid alloy electrode. The cell was used for determination of the oxygen potentials in liquid dilute Cu-Cr and Cu-Zr alloys. The reference electrode was Cr,Cr2O3. Emf measurements were performed in the temperature range of 1400-1580K and composition range of 0.198-3.10at%Cr-Cu alloys, and 1380-1465K, 0.085-0.761at%Zr-Cu alloys. The composition of liquid alloys were determined by picking up from the liquid alloys and ICP analysis. By use of the newly devised cell construction in this study, stable emf values were obtained at each temperature and alloy composition. Emf values were corrected by using the parameter for electronic contribution of the YSZ. Activity of Cr obeys Henry’s law and activity coefficient at infinitely dilute alloys of Cr in Cu-Cr alloys are: lng0 Cr =(3.80 at 1423K, (3.57 at 1473K, (3.38 at 1523K and (3.20 at 1573K. At 1423 K activity coefficient of Zr at infinitely diluted alloy is lnγo Zr = -4.0.

  10. Influence of the crystallization condition on Al–Si–Cu casting alloys structure

    OpenAIRE

    L.A. Dobrzański; W. Borek; R. Maniara

    2006-01-01

    Purpose: The purpose of this paper is to show the effect of solidification rate on microstructural features,hardness and microhardness of Al–Si–Cu alloys in as cast state.Design/methodology/approach: The main base of the paper is to compare the properties of aluminium castalloys of ACAlSi7Cu, ACAlSi7Cu2 and ACAlSi7Cu4. Microstructural features were characterised using lightoptical microscopy. For rapid determination of the parameters: grains size and Secondary Dendrite Arm Spacing– SDAS were ...

  11. Stress Dispersed Cu Metal Anode by Laser Multiscale Patterning for Lithium-Ion Batteries with High Capacity

    Directory of Open Access Journals (Sweden)

    Jin-Young So

    2018-06-01

    Full Text Available Electric power production continues to increase as the industry advances, and the demand for high-capacity batteries for efficient operation of the electric power produced is higher than ever before. Si has been attracting a great deal of attention recently as an anode electrode material because of its high theoretical capacity. However, it suffers from significant capacity-loss, resulting from the volume-expansion of Si during charge and discharge cycles. Inspired by the multiscale structures commonly found in nature, we attempt to solve this problem by patterning the surface of the Cu current-collector. To this end, we develop a direct, one-step method using laser patterning to manufacture a multiscale structure on the surface of the current-collector. The inherent exfoliation characteristic of the Cu current-collector allows the spontaneous formation of the multiscale structure while being irradiated with a laser. A micro/nano structure, with a different surface area, is fabricated by varying the laser output at three levels, and the batteries prepared with the fabricated Cu current-collector are tested to evaluate their charge-discharge characteristics and electrochemical impedance. The results show that the multiscale structure reduces mechanical stress. The initial capacity of the Cu current-collector is proportional to the laser output, and the initial capacity of the coin cell prepared with the Cu current-collector, fabricated at the highest laser output, is 396.7% higher than that of the coin cell prepared with a bare Cu current-collector. The impedance is inversely proportional to the laser output. The charge transfer resistance of the coin cell prepared with the Cu current-collector and irradiated with the highest laser output is 190.2% lower than that of the coin cell prepared with the bare Cu current-collector.

  12. 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.

  13. Comparison of GRCop-84 to Other Cu Alloys with High Thermal Conductivities

    Science.gov (United States)

    deGroh, Henry C., III; Ellis, David L.; Loewenthal, William S.

    2007-01-01

    The mechanical properties of six highly conductive copper alloys, GRCop-84, AMZIRC, GlidCop Al-15, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z were compared. Tests were done on as-received hard drawn material, and after a heat treatment designed to simulate a brazing operation at 935 C. In the as-received condition AMZIRC, GlidCop Al-15, Cu- 1Cr-0.1Zr and Cu-0.9Cr had excellent strengths at temperatures below 500 C. However, the brazing heat treatment substantially decreased the mechanical properties of AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z. The properties of GlidCop Al-15 and GRCop-84 were not significantly affected by the heat treatment. Thus there appear to be advantages to GRCop-84 over AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z if use or processing temperatures greater than 500 C are expected. Ductility was lowest in GlidCop Al-15 and Cu-0.9Cr; reduction in area was particularly low in GlidCop Al-15 above 500 C, and as- received Cu-0.9Cr was brittle between 500 and 650 C. Tensile creep tests were done at 500 and 650 C; the creep properties of GRCop-84 were superior to those of brazed AMZIRC, Cu-1Cr- 0.1Zr, Cu-0.9Cr, and NARloy-Z. In the brazed condition, GRCop-84 was superior to the other alloys due to its greater strength and creep resistance (compared to AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z) and ductility (compared to GlidCop Al-15).

  14. Corrosion and Discharge Behaviors of Mg-Al-Zn and Mg-Al-Zn-In Alloys as Anode Materials

    Directory of Open Access Journals (Sweden)

    Jiarun Li

    2016-03-01

    Full Text Available The Mg-6%Al-3%Zn and Mg-6%Al-3%Zn-(1%, 1.5%, 2%In alloys were prepared by melting and casting. Their microstructures were investigated via metallographic and energy-dispersive X-ray spectroscopy (EDS analysis. Moreover, hydrogen evolution and electrochemical tests were carried out in 3.5 wt% NaCl solution aiming at identifying their corrosion mechanisms and discharge behaviors. The results suggested that indium exerts an improvement on both the corrosion rate and the discharge activity of Mg-Al-Zn alloy via the effects of grain refining, β-Mg17Al12 precipitation, dissolving-reprecipitation, and self-peeling. The Mg-6%Al-3%Zn-1.5%In alloy with the highest corrosion rate at free corrosion potential did not perform desirable discharge activity indicating that the barrier effect caused by the β-Mg17Al12 phase would have been enhanced under the conditions of anodic polarization. The Mg-6%Al-3%Zn-1.0%In alloy with a relative low corrosion rate and a high discharge activity is a promising anode material for both cathodic protection and chemical power source applications.

  15. Superparamagnetism in CuFeInTe{sub 3} and CuFeGaTe{sub 3} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grima-Gallardo, P.; Alvarado, F.; Munoz, M.; Duran, S.; Quintero, M.; Nieves, L.; Quintero, E.; Tovar, R.; Morocoima, M. [Centro de Estudios en Semiconductores (CES), Fac. Ciencias, Dpto. Fisica, Universidad de Los Andes, Merida (Venezuela); Ramos, M.A. [Laboratorio de Difraccion y Fluorescencia de Rayos-X, Instituto Zuliano de Investigaciones Tecnologicas (INZIT), La Canada de Urdaneta, Estado Zulia (Venezuela)

    2012-06-15

    The temperature dependencies of DC magnetic susceptibilities, {chi}(T), of CuFeInTe{sub 3} and CuFeGaTe{sub 3} alloys were measured in a SQUID apparatus using the protocol of field cooling (FC) and zero FC (ZFC). The FC curves of both samples reflect a weak ferromagnetic (or ferrimagnetic) behavior with a nearly constant value of {chi}(T) in the measured temperature range (2-300 K) indicating that the critical temperatures (T{sub c}) are >300 K. The ZFC curves diverges from FC, showing irreversibility temperatures (T{sub irr}) of {proportional_to}250 K for CuFeInTe{sub 3} and >300 K for CuFeGaTe{sub 3}, suggesting that we are dealing with cluster-glass systems in a superparamagnetic state. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Synthesis and application of a novel Cu/RGO@Pb alloy for lead-acid batteries

    International Nuclear Information System (INIS)

    Wu, Yumeng; Zhao, Ruirui; Zhou, Huawen; Zhang, Dejing; Zhao, Wei; Chen, Hongyu

    2016-01-01

    In this work, a novel Cu/RGO@Pb alloy was prepared successfully and tested in the simulated lead-acid battery environment. In preparing the novel alloy, Cu/RGO composite was firstly synthesized in order to increase the wettability of RGO to Pb, and then the composite was added to the molten lead to obtain the target alloy. Scanning electron microscope, energy dispersive spectrometer, X-ray diffraction as well as electrochemical measurements were employed to evaluate the performance of the obtained composite and alloy. Results show that the prepared Cu/RGO@Pb possessed higher oxygen evolution over-potential and lower hydrogen evolution over-potential than the contrast alloy, indicating this novel alloy was more suitable for using as positive grids in lead acid batteries. Moreover, the RGO additive could inhibit the formation of Pb(II) and Pb(IV) film on the surface of the alloy, which could enhance the deep-charge/discharge performance of the grids and improve the corrosion resistance.

  17. L10 ordered structures in Al-Cu-(Mg) alloys at the early stages of elevated temperature aging

    Energy Technology Data Exchange (ETDEWEB)

    Fuzhong, X.; Mingpu, W.

    2016-07-01

    This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. %) alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg) alloys were characterized by Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HTREM). 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg) alloys during aging. (Author)

  18. L10 ordered structures in Al-Cu-(Mg) alloys at the early stages of elevated temperature aging

    International Nuclear Information System (INIS)

    Fuzhong, X.; Mingpu, W.

    2016-01-01

    This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. %) alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg) alloys were characterized by Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HTREM). 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg) alloys during aging. (Author)

  19. Swift heavy ion irradiation of Cu-Zn-Al and Cu-Al-Ni alloys.

    Science.gov (United States)

    Zelaya, E; Tolley, A; Condo, A M; Schumacher, G

    2009-05-06

    The effects produced by swift heavy ions in the martensitic (18R) and austenitic phase (β) of Cu based shape memory alloys were characterized. Single crystal samples with a surface normal close to [210](18R) and [001](β) were irradiated with 200 MeV of Kr(15+), 230 MeV of Xe(15+), 350 and 600 MeV of Au(26+) and Au(29+). Changes in the microstructure were studied with transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). It was found that swift heavy ion irradiation induced nanometer sized defects in the 18R martensitic phase. In contrast, a hexagonal close-packed phase formed on the irradiated surface of β phase samples. HRTEM images of the nanometer sized defects observed in the 18R martensitic phase were compared with computer simulated images in order to interpret the origin of the observed contrast. The best agreement was obtained when the defects were assumed to consist of local composition modulations.

  20. Temperature Effects on the Tensile Properties of Precipitation-Hardened Al-Mg-Cu-Si Alloys

    Directory of Open Access Journals (Sweden)

    J.B. Ferguson

    2016-02-01

    Full Text Available Because the mechanical performance of precipitation-hardened alloys can be significantly altered with temperature changes, understanding and predicting the effects of temperatures on various mechanical properties for these alloys are important. In the present work, an analytical model has been developed to predict the elastic modulus, the yield stress, the failure stress, and the failure strain taking into consideration the effect of temperatures for precipitation-hardenable Al-Mg-Cu-Si Alloys (Al-A319 alloys. In addition, other important mechanical properties of Al-A319 alloys including the strain hardening exponent, the strength coefficient, and the ductility parameter can be estimated using the current model. It is demonstrated that the prediction results based on the proposed model are in good agreement with those obtained experimentally in Al-A319 alloys in the as-cast condition and after W and T7 heat treatments.

  1. Growth and characterization of NixCu1-x alloy films, NixCu1-x/NiyCu1-y multilayers, and nanowires

    International Nuclear Information System (INIS)

    Kazeminezhad, I.

    2001-12-01

    It was found that it is possible to grow Ni x Cu 1-x alloy systems of arbitrary composition by electrodepositing well-defined sub-monolayer quantities of Ni and Cu in alternation using a new method based on that used previously to prepare potentiostatically deposited magnetic multilayers from a single sulphamate-based electrolyte. Following growth, the chemical composition of Ni x Cu 1-x alloy films was obtained by ZAF-corrected energy dispersive X-Ray (EDX) analysis and less than a 4% difference between the nominal and actual composition was observed. The structure of the films was investigated by high-angle X-ray diffractometry (HAXRD) and transmission electron microscopy (TEM). The films grown on polycrystalline Cu substrates had (100) texture, while those grown on Au-coated glass had (111) texture. Some evidence of Ni clustering was obtained by vibrating sample magnetometry (VSM). Self-organisation of the deposited metal was suggested for Ni potentials more positive than ∼-1.4V. The transition from a Ni/Cu multilayer to a Ni x Cu 1-x alloy was also studied and an interesting aspect, namely a plateau region in a plot of magnetisation as a function of Ni layer thickness was observed, suggesting a preferred Ni cluster size in these alloy films. Anisotropic magnetoresistance (AMR) of the films decreased with increasing Cu content at 300K and 77K. SQUID measurements for Ni 0.52 Cu 0.48 and Ni 0.62 CU 0.38 films showed that they become much more strongly ferromagnetic at low temperatures. Evidence for blocked -superparamagnetic behaviour above a blocking temperature (T B ) of the films was obtained from zero-field-cooled (ZFC) and field-cooled (FC) magnetic susceptibility measurements. Ni x Cu 1-x /Ni y Cu 1-y alloy/alloy multilayer films with short repeat distance were successfully fabricated using this method. Up to third order satellite peaks observed in HAXRD showed that the interface is sharp. Room temperature longitudinal magnetoresistance measurements showed

  2. Nanoporous alumina formed by self-organized two-step anodization of Ni{sub 3}Al intermetallic alloy in citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Stepniowski, Wojciech J., E-mail: wstepniowski@wat.edu.pl [Department of Advanced Materials and Technology, Faculty of New Technologies and Chemistry, Military University of Technology, Kaliskiego 2 Str., 00-908 Warszawa (Poland); Cieslak, Grzegorz; Norek, Malgorzata; Karczewski, Krzysztof; Michalska-Domanska, Marta; Zasada, Dariusz; Polkowski, Wojciech; Jozwik, Pawel; Bojar, Zbigniew [Department of Advanced Materials and Technology, Faculty of New Technologies and Chemistry, Military University of Technology, Kaliskiego 2 Str., 00-908 Warszawa (Poland)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Anodic porous alumina was formed by Ni{sub 3}Al intermetallic alloy anodization. Black-Right-Pointing-Pointer The anodizations were conducted in 0.3 M citric acid. Black-Right-Pointing-Pointer Nanopores geometry depends on anodizing voltage. Black-Right-Pointing-Pointer No barrier layer was formed during anodization. - Abstract: Formation of the nanoporous alumina on the surface of Ni{sub 3}Al intermetallic alloy has been studied in details and compared with anodization of aluminum. Successful self-organized anodization of this alloy was performed in 0.3 M citric acid at voltages ranging from 2.0 to 12.0 V using a typical two-electrode cell. Current density records revealed different mechanism of the porous oxide growth when compared to the mechanism pertinent for the anodization of aluminum. Electrochemical impedance spectroscopy experiments confirmed the differences in anodic oxide growth. Surface and cross-sections of the Ni{sub 3}Al intermetallic alloy with anodic oxide were observed with field-emission scanning electron microscope and characterized with appropriate software. Nanoporous oxide growth rate was estimated from cross-sectional FE-SEM images. The lowest growth rate of 0.14 {mu}m/h was found for the anodization at 0 Degree-Sign C and 2.0 V. The highest one - 2.29 {mu}m/h - was noticed for 10.0 V and 30 Degree-Sign C. Pore diameter was ranging from 18.9 nm (2.0 V, 0 Degree-Sign C) to 32.0 nm (12.0 V, 0 Degree-Sign C). Interpore distance of the nanoporous alumina was ranging from 56.6 nm (2.0 V, 0 Degree-Sign C) to 177.9 nm (12.0 V, 30 Degree-Sign C). Pore density (number of pore occupying given area) was decreasing with anodizing voltage increase from 394.5 pores/{mu}m{sup 2} (2.0 V, 0 Degree-Sign C) to 94.9 pores/{mu}m{sup 2} (12.0 V, 0 Degree-Sign C). All the geometrical features of the anodic alumina formed by two-step self-organized anodization of Ni{sub 3}Al intermetallic alloy are depending on the

  3. Producing a particle-reinforced AlCuMgMn alloy by means of mechanical alloying; Herstellung einer partikelverstaerkten AlCuMgMn-Legierung durch mechanisches Legieren

    Energy Technology Data Exchange (ETDEWEB)

    Nestler, D.; Wielage, B. [TU Chemnitz, Institut fuer Werkstoffwissenschaft und Werkstofftechnik (Germany); Siebeck, S.

    2012-07-15

    High-energy ball milling (HEM) with subsequent consolidation is a suitable method to produce particle-reinforced aluminium materials. The task of HEM is to distribute the reinforcement particles as homogeneously as possible. A further application of HEM is mechanical alloying (MA). This paper deals with the combination of both applications. Pure metallic powders (Al, Cu, Mg, Mn) were milled together with SiC particles up to 10 h. The composition of the metallic powder corresponds to that of the alloy AA2017 (3.9% Cu, 0.7% Mg, 0.6% Mn). In previous experiments [1], this alloy was used in the form of atomized powder. The changes in microstructure during the formation of the composite powder have been studied by light microscopy, SEM, EDXS and XRD. The results show that the production of composite powders in a single step is possible. This not only allows the economical production of such powders, but also facilitates the use of alloy compositions that are not producible via the melting route, or only producible with difficulty via the melting route. It's possible to produce tailor-made-alloys. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Microstructural study and numerical simulation of phase decomposition of heat treated Co–Cu alloys

    Directory of Open Access Journals (Sweden)

    A.M. Mebed

    2014-12-01

    Full Text Available The influence of heat treatment on the phase decomposition and the grain size of Co–10 at% Cu alloy were studied. Few samples were aged in a furnace for either 3 or 5 h and then quenched in iced water. The materials and phase compositions were investigated using energy dispersive spectrometry and X-ray diffraction techniques. X-ray diffraction analysis showed that the samples contained Co, Cu, CuO, CoCu2O3, CoCuO2 phases in different proportions depending on the heat treatment regimes. The formation of dendrite Co phase rendered the spinodal decomposition while the oxidations prevent the initiation of the spinodal decomposition even for a deep long aging inside the miscibility gap. Since the Bragg reflections from different phases of Co–Cu alloy significantly overlap, the crystal structural parameters were refined with FULLPROF program. The shifts in the refined lattice constants (a, b and c, the space group and the grain size were found to be phase- and heat treatment-dependant. Two-dimensional computer simulations were conducted to study the phase decomposition of Co–Cu binary alloy systems. The excess free energy as well as the strain energy, without a priori knowledge of the shape or the position of the new phase, was precisely evaluated. The results indicate that the morphology and the shape of the microstructure agree with SEM observation.

  5. Optimization of mechanical properties, biocorrosion properties and antibacterial properties of as-cast Ti-Cu alloys.

    Science.gov (United States)

    Zhang, Erlin; Ren, Jing; Li, Shengyi; Yang, Lei; Qin, Gaowu

    2016-10-21

    Ti-Cu sintered alloys have shown good antibacterial abilities. However, the sintered method (powder metallurgy) is not convenient to produce devices with a complex structure. In this paper, Ti-Cu alloys with 2.0, 3.0 and 4.0 wt.% Cu were prepared in an arc melting furnace and subjected to different heat treatments: solid solution and ageing, to explore the possibility of preparing an antibacterial Ti-Cu alloy by a casting method and to examine the effect of Cu content. Phase identification was conducted on an XRD diffraction meter, and the microstructure was observed by a metallographic microscope, a scanning electron microscope (SEM) with energy disperse spectroscopy (EDS) and transmission electron microscopy (TEM). Microhardness and the compressive property of Ti-Cu alloys were tested, and the corrosion resistance and antibacterial activity were assessed in order to investigate the effect of the Cu content. Results showed that the as-cast Ti-Cu alloys exhibited a very low antibacterial rate against Staphylococcus aureus (S. aureus). Heat treatment improved the antibacterial rate significantly, especially after a solid and ageing treatment (T6). Antibacterial rates as high as 90.33% and 92.57% were observed on Ti-3Cu alloy and Ti-4Cu alloy, respectively. The hardness, the compressive yield strength, the anticorrosion resistance and the antibacterial rate of Ti-Cu alloys increased with an increase of Cu content in all conditions. It was demonstrated that homogeneous distribution and a fine Ti 2 Cu phase played a very important role in the mechanical property, anticorrosion and antibacterial properties. Furthermore, it should be pointed out that the Cu content should be at least 3 wt.% to obtain good antibacterial properties (>90% antibacterial rate) as well as satisfactory mechanical properties.

  6. 27Al, 63Cu NMR spectroscopy and electrical transport in Heusler Cu-Mn-Al alloy powders

    Science.gov (United States)

    Nadutov, V. M.; Perekos, A. O.; Kokorin, V. V.; Trachevskii, V. V.; Konoplyuk, S. M.; Vashchuk, D. L.

    2018-02-01

    The ultrafine powder of the Heusler Cu-13,1Mn-12,6Al (wt.%) alloy produced by electrical spark dispersion (ESD) in ethanol and the pellets prepared by pressing of the powders and aged in various gas environment (air, Ar, vacuum) were studied by XRD, nuclear magnetic resonance, magnetic and electric transport methods. The constituent phases were identified as b.c.c. α-Cu-Mn-Al, f.c.c. γ-Cu-Mn-Al, Cu2MnAl, and oxides. The sizes of the coherently scattering domains (CSD) and the saturation magnetizations were in the range of 4-90 nm and 0-1.5 Am2/kg, respectively. 27Al and 63Cu NMR spectra of the powders and pellets have shown hyperfine structure caused by contributions from atomic nuclei of the constituent phases. The aging of pellets in different gas environments had effect on their phase composition but no effect on dispersion of the phases. In contrast to the as-cast alloy, electrical resistance of the pellets evidenced semiconducting behavior at elevated temperatures due to the presence of metal oxides formed on the surfaces of nanoparticles.

  7. Theoretical calculations of the surface tension of Ag(1-x)-Cu(x) liquid alloys

    International Nuclear Information System (INIS)

    Aqra, Fathi; Ayyad, Ahmed

    2011-01-01

    Highlights: → A thermodynamic model for calculating the surface tension, and its temperature and composition dependences, of liquid binary alloys is described. → The model does not require the prior knowledge of the surface concentration and Gibbs energy. → The surface tension of the liquid Ag-Cu binary alloys has been calculated as a function of temperature and concentration. → The calculated values agree well with existing experimental data. - Abstract: The surface tension of silver-copper binary liquid alloys is calculated, in the frame work of Eyring theory. The calculations were made for different compositions (mole fraction, x Cu = 0, 0.2, 0.4, 0.6, 0.8 and 1), in the temperature range 1100-1800 K. The surface tension decreases with temperature increase, at a fixed copper fraction x Cu , and increases with increasing copper content. The calculated results are appropriately compared with existing literature data.

  8. Research on aging precipitation in a Cu-Cr-Zr-Mg alloy

    International Nuclear Information System (INIS)

    Su Juanhua; Dong Qiming; Liu Ping; Li Hejun; Kang Buxi

    2005-01-01

    The effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy were investigated. Aging precipitation phase was dealt with by transmission electronic microscope (TEM). After solid solution was treated at 920 deg. C and aged at 470 deg. C for 4 h, the fine precipitation of an ordered compound CrCu 2 (Zr, Mg) is found in copper matrix as well as fine Cr and Cu 4 Zr. Along the grain boundary, there are larger chromium. The hardness and electrical conductivity can reach 109 HV and 80% IACS, respectively. Sixty percent cold-rolled deformation prior to aging at 470 deg. C enhances the hardness of the alloy. The coherent precipitates Cr in copper matrix and the dislocations pinned by the fine precipitates are responsible for maximum strengthening of the alloy. So the hardness 165 HV and electrical conductivity 79.2% IACS are available

  9. Similar and dissimilar friction welding of Zr-Cu-Al bulk glassy alloys

    International Nuclear Information System (INIS)

    Shin, Hyung-Seop; Park, Jung-Soo; Jung, Yoon-Chul; Ahn, Jung-Ho; Yokoyama, Yoshihiko; Inoue, Akihisa

    2009-01-01

    The friction welding of three kinds of Zr-Cu-Al bulk glassy alloys (BGAs) which show eutectic or hypoeutectic compositions to similar and dissimilar BGAs and crystalline metals has been tried. The shape and volume of the protrusion formed at the weld interface were investigated. In order to characterize the friction welded interface, micrographic observation and X-ray diffraction analysis on the weld cross-section were carried out. A successful joining of Zr-Cu-Al bulk glassy alloys to similar and dissimilar BGAs was achieved without occurrence of crystallizations at the weld interface through the precise control of friction conditions. In addition, the joining of Zr 50 Cu 40 Al 10 BGA to crystalline alloys was tried, but it was only successful for specific material combinations. The residual strength after welding of dissimilar BGAs was evaluated by the four-point bending test.

  10. Thermodynamic properties of the liquid Bi-Cu-Sn lead-free solder alloys

    Directory of Open Access Journals (Sweden)

    Kopyto M.

    2009-01-01

    Full Text Available The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Po2=0.2:1 atm Measurements were carried out for three cross-sections with constant Bi/Cu ratio equal to: 1/3, 1 and 3 and for various tin content varying every 10%, resulting in a total of 26 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.

  11. On the thermal degradation of the two way memory effect in Cu-Al-Be alloys

    International Nuclear Information System (INIS)

    Flores-Zuniga, H.; Rios-Jara, D.

    1994-01-01

    The mechanisms associated to such a degradation of the Two Way Shape Memory Effect (TWSME) are still being discussed. In Cu-Al-Ni alloys two different steps, with different rates of degradation of the TWSME, were observed on aging at temperatures between 200 and 220 C. The first step was associated with the annihilation of the dislocations created during the training process. The second step was attributed to an oriented bainitic type precipitation. In Cu-Zn-Al alloys, the observed degradation of the TWSME with aging at temperatures between 100 and 140 C, was also associated with two mechanisms: first to the annihilation of dislocations and next to the precipitation of an α phase. In the present work, the same type of study was performed for Cu-Al-Be alloys. However, in-situ transmission electron microscopy (TEM) observations of the effect of temperature were included, which revealed the actual mechanisms driving the TWSME degradation process

  12. Preparation and Properties of Mg-Cu-Y-Al bulk Amorphous Alloys

    DEFF Research Database (Denmark)

    Pryds, Nini; Eldrup, Morten Mostgaard; Ohnuma, M.

    2000-01-01

    Bulk amorphous (Mg(1-gamma)Al(gamma))(60)CU(30)Y(10) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper wedge mould. The temperature vs, time was recorded during the cooling and solidification process of the melt and compared with a spacial and tempo......Bulk amorphous (Mg(1-gamma)Al(gamma))(60)CU(30)Y(10) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper wedge mould. The temperature vs, time was recorded during the cooling and solidification process of the melt and compared with a spacial...... temperatures in specimens containing a few percent Al. The alloy with no Al crystallises apparently without the formation of nanoparticles. The critical cooling rate for the formation of an amorphous Mg(60)CU(30)Y(10) specimen was determined experimentally by a combination of DSC data and temperature vs, time...

  13. Control of segregation in squeeze cast Al-4.5Cu binary alloy

    Energy Technology Data Exchange (ETDEWEB)

    Durrant, G. [Oxford Univ. (United Kingdom). Dept. of Materials; Gallerneault, M. [Alcan International Ltd., Kingston, ON (Canada); Cantor, B. [Oxford Univ. (United Kingdom). Dept. of Materials

    1997-10-01

    The high pressure applied in squeeze casting allows Al alloys of wrought composition to be cast to near net-shape, although their long freezing range leads to the segregation of alloying elements. In this paper we present results on the squeeze casting and gravity casting of a model Al-4.5 wt%Cu alloy. Squeeze cast Al-4.5Cu has a normal segregation pattern with eutectic macrosegregates towards the centre of the billet, whereas gravity cast material has a typical inverse segregation pattern. Normal segregation in squeeze cast Al-4.5Cu is due to large temperature gradients during solidification. Segregation can be minimized by releasing the applied pressure during solidification to allow backflow of the interdendritic fluid, or by the addition of grain refiner to remove the large columnar dendritic growth structure. (orig.)

  14. Study of the properties of internal oxidized Cu - Al - Ti - Hf alloys

    International Nuclear Information System (INIS)

    Solopov, V.I.; Daneliya, E.P.; Daneliya, G.V.; Lebasova, O.P.

    1982-01-01

    Investigation results of mechanical properties and electric conductivity of rods of internally oxidized alloys Cu-Al-Ti-Hf depending on chemical composition, varying in the limits ensuring the formation of disperse enough and evenly distributed over the volume oxide phase. (0-1%Al, 0-0.5%Ti, 0-0.3%Hf, the restcopper), in the process of internal oxidation are presented. Internally oxidized alloys Cu-Al-Ti-Hf have increased strength properties with insignificant increase of specific electric resistance as compared with the known internally oxidized alloys Cu-Al. At that, the best combination of physicomechanical properties is achieved at small contents of titanium (0.01-0.05%) and hafnium (0.01-0.1%)

  15. Study On Nanohardness Of Phases Occurring In ZnAl22Cu3 And ZnAl40Cu3 Alloys

    Directory of Open Access Journals (Sweden)

    Michalik R.

    2015-06-01

    Full Text Available Zn-Al alloys are mainly used due to their high tribological and damping properties. A very important issue is determination of the hardness of the phases present in the Zn-Al-Cu alloys. Unfortunately, in literature there is lack of studies on the hardness of the phases present in the alloys Zn-Al-Cu. The aim of this research was to determine the hardness of the phases present in the ZnAl22Cu3Si and ZnAl40Cu3Si alloys. The scope of the research included examination of the structure, chemical composition of selected micro-regions and hardness of phases present in the examined alloys. The research carried out has shown, that CuZn4 phase is characterized by a similar hardness as the hardness of the interdendritic areas. The phases present in the structure of ZnAl40Cu3 and ZnAl22Cu3 alloys after soaking at the temperature of 185 °C are characterized by lower hardness than the phase present in the structure of the as-cast alloys.

  16. First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    LIAO Fei

    2016-12-01

    Full Text Available Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (Ecoh decreases in the order MgZn2 > Al2CuMg > Al2Cu, whereas the formation enthalpy (ΔH decreases in the order MgZn2 > Al2Cu > Al2CuMg. Al2Cu can act as a strengthening phase for its ductile and high Young's modulus. The Al2CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al2Cu, Al2CuMg and MgZn2, and that improves the structural stability. In order to improve the alloys' performance further, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.

  17. Gibbsian and radiation-induced segregation in Cu--Li and Al--Li alloys

    International Nuclear Information System (INIS)

    Gruen, D.M.; Krauss, A.R.; Susman, S.; Venugopalan, M.; Ron, M.

    1983-01-01

    Previous experiments on segregation in dilute alloys of lithium in aluminum have demonstrated rapid enrichment of lithium in the uppermost monolayer, as well as a slower buildup in the subsurface region as a result of radiation-induced segregation effects during sputtering. Surface and subsurface enrichment of lithium in copper and aluminum alloys has been observed by secondary ion mass spectroscopy (SIMS), Auger electron spectroscopy (AES), and x-ray photoemission spectroscopy (XPS). The activation energies for lithium diffusion in Cu and Al have been measured and segregation kinetics are compared for dilute alloys of Li in Cu and Al, and a high lithium content copper alloy. The results are interpreted in terms of both Gibbsian and radiation-induced segregation effects

  18. Microstructure and corrosion resistance of Sm-containing Al-Mn-Si-Fe-Cu alloy

    Directory of Open Access Journals (Sweden)

    Han Yuyin

    2017-12-01

    Full Text Available Optimizing alloy composition is an effective way to improve physical and chemical properties of automobile heat exchanger materials.A Sm-containing Al-Mn-Si-Fe-Cu alloy was investigated through transmission electron microscopy,scanning electron microscopy,and electrochemical measurement.Experimental results indicated that main phases distributed in the alloy wereα-Al(Mn,FeSi,Al2Sm and Al10Cu7Sm2.Alloying with Sm element could refine the precipitated α-Al(Mn,FeSi phase.Polarization testing results indicated that the corrosion surfacewas mainly composed of pitting pits and corrosion products.Sea water acetic acid test(SWAAT showed that corrosion loss increased first and then slowed downwith increase of the corrosion time.

  19. Low Cycle Mechanical and Fatigue Properties of AlZnMgCu Alloy

    Directory of Open Access Journals (Sweden)

    Pysz S.

    2016-03-01

    Full Text Available The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn aluminium alloy and estimates possibilities of its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the 7xxx series. For analysis, wrought AlZnMgCu alloy (7075 was selected. Its potential of the estimated as-cast mechanical properties indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue properties support the thesis adopted, while the design works further confirm these assumptions.

  20. Fracture behaviour of Cu-Al-Ni shape memory alloys obtained by powder metallurgy

    International Nuclear Information System (INIS)

    Rodriguez, P. P.; Perez-Saez, R. B.; Recarte, V.; San Juan, J.M.; Ruano, O. A.; No, M. L.

    2001-01-01

    Polycrystalline Cu-Al-Ni shape memory alloys have been scarcely employed for technological applications due to their high brittleness. The development of a new elaboration technique based on powder metallurgy has recently overcome this problem, through the improvement of the ductility of the produced alloys without affecting its shape memory properties. The fracture behaviour of an alloy obtained using the elaboration technique has been studied by means of Scanning Electron Microscopy and mechanical testing. The results show a ductile fracture with a maximum strain close to 13%, which is the best fracture behaviour obtained for Cu-Al-Ni polycrystals. The microstructure of such alloys ha been studied by means of Transmission Electron Microscopy, showing a poligonyzed structure in which martensite plated passing through the subboundaries easily. (Author) 19 refs

  1. Recovery of the mechanical properties on the Al-4wt%Cu alloy

    International Nuclear Information System (INIS)

    Chemingui, M; Kassis, K; Khitouni, M; Masmoudi, J; Kolsi, A W

    2010-01-01

    The recovery of the mechanical properties on the Al-4%wtCu alloy was investigated by indentation after cold rolling. The microstructural evolution was performed using optical and scanning electron microscopies. The annealing at 200 deg. C of the quenched and rolled alloy gives higher mechanical qualities. At temperatures up to 200 deg. C, the alloy has no softening by recovery, but on the contrary a hardening behaviour was observed. This later is attributed to the presence of the intermediate θ'' and θ' phases. Nevertheless, the ageing in high temperature product the coalescence of iron particles and of Al 2 Cu precipitates. These phases are essentially localized in the grain boundaries, which caused the damage of the alloy.

  2. Correlation between the oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys

    Science.gov (United States)

    Park, Sang-Yoon; Lee, Myung-Ho; Jeong, Yong-Hwan; Jung, Youn-Ho

    2004-12-01

    The correlation between the oxide impedance and corrosion behavior of two series of Zr-Nb-Sn-Fe-Cu alloys was evaluated. Corrosion tests were performed in a 70 ppm LiOH aqueous solution at 360°C for 300 days. The results of the corrosion tests revealed that the corrosion behavior of the alloys depended on the Nb and Sn content. The impedance characteristics for the pre- and post-transition oxide layers formed on the surface of the alloys were investigated in sulfuric acid at room temperature. From the results, a pertinent equivalent circuit model was preferably established, explaining the properties of double oxide layers. The impedance of the oxide layers correlated with the corrosion behavior; better corrosion resistance always showed higher electric resistance for the inner layers. It is thus concluded that a pertinent equivalent circuit model would be useful for evaluating the long-term corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys.

  3. Synthesis and Characterization of Nanocrystalline Al-20 at. % Cu Powders Produced by Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Molka Ben Makhlouf

    2016-06-01

    Full Text Available Mechanical alloying is a powder processing technique used to process materials farther from equilibrium state. This technique is mainly used to process difficult-to-alloy materials in which the solid solubility is limited and to process materials where nonequilibrium phases cannot be produced at room temperature through conventional processing techniques. This work deals with the microstructural properties of the Al-20 at. % Cu alloy prepared by high-energy ball milling of elemental aluminum and copper powders. The ball milling of powders was carried out in a planetary mill in order to obtain a nanostructured Al-20 at. % Cu alloy. The obtained powders were characterized using scanning electron microscopy (SEM, differential scanning calorimetry (DSC and X-ray diffraction (XRD. The structural modifications at different stages of the ball milling are investigated with X-ray diffraction. Several microstructure parameters such as the crystallite sizes, microstrains and lattice parameters are determined.

  4. Evaluation of Cracking Causes of AlSi5Cu3 Alloy Castings

    Directory of Open Access Journals (Sweden)

    Eperješi Š.

    2014-10-01

    Full Text Available Recently, the castings made from aluminum-silicon alloys by pressure die casting are increasingly used in the automotive industry. In practice, on these castings are high demands, mainly demands on quality of their structure, operating life and safety ensuring of their utilization. The AlSi5Cu3 alloy castings are widely used for production of car components. After the prescribed tests, the cracks and low mechanical properties have been identified for several castings of this alloy, which were produced by low pressure casting into a metal mould and subsequent they were heat treated. Therefore, analyses of the castings were realized to determine the causes of these defects. Evaluation of structure of the AlSi5Cu3 alloy and causes of failure were the subjects of investigation presented in this article.

  5. Investigation of Microstructure in Solid State Welded Al-Cu-Li alloy

    Directory of Open Access Journals (Sweden)

    No Kookil

    2016-01-01

    Full Text Available Al-Li alloys have been extensively used in aerospace vehicle structure since the presence of lithium increases the modulus and reduce the density of the alloy. Especially the third generation Al-Cu-Li alloy shows enhanced fracture toughness at cryogenic temperatures so that the alloy has been used on the fuel tank of space launchers, like Super Lightweight External Tank of the Space Shuttle. Since the commercial size of the plate cannot accommodate the large tank size of the launcher, joining several pieces is required. However, lithium is highly reactive and its compounds can decompose with heat from conventional fusion welding and form different types of gases which result in formation of defects. In this study, the microstructure change is investigated after solid state welding process to join the Al-Cu-Li sheets with optical and transmission electron microscopic analysis of precipitates.

  6. Directional solidification of Zn-Al-Cu eutectic alloy by the vertical Bridgman method

    Directory of Open Access Journals (Sweden)

    Büyük U.

    2015-01-01

    Full Text Available In the present work, the effect of growth rate and temperature gradient on microstructure and mechanical properties of Zn-7wt.%Al-4wt.%Cu eutectic alloy has been investigated. Alloys prepared under steady-state conditions by vacuumed hot filing furnace. Then, the alloys were directionally solidified upward with different growth rates (V=11.62-230.77 mm/s at a constant temperature gradient (G=7.17 K/mm and with different temperature gradients (G=7.17-11.04 K/mm at a constant growth rate (V=11.62 mm/s by a Bridgman furnace. The microstructures were observed to be lamellae of Zn, Al and broken lamellae CuZn4 phases from quenched samples. The values of eutectic spacing, microhardness and ultimate tensile strength of alloys were measured. The dependency of the microstructure and mechanical properties on growth rate and temperature gradient were investigated using regression analysis.

  7. Grain size and temperature influence on the toughness of a CuAlBe shape memory alloy

    International Nuclear Information System (INIS)

    Albuquerque, Victor Hugo C. de; Melo, Tadeu Antonio de A; Gomes, Rodinei M.; Lima, Severino Jackson G. de; Tavares, Joao Manuel R.S.

    2010-01-01

    Research highlights: → This work evaluated the capacity of a CuAlBe alloy to absorb energy until rupture. → The V-notch Charpy test was adopted at -150, -100, -50, 0, 50, 100 and 150 deg. C. → Charpy tests were complemented by DSC, DSC with optical microscope and by SEM. → First work to analyze the toughness of a CuAlBe alloy based on the Charpy test. → The results are of relevant value to enhance the understanding of the CuAlBe alloy. - Abstract: This work is a study of the influence of grain size and temperature on the toughness of CuAlBe shape memory alloys with (CuAlBeNbNi) and without NbNi (CuAlBe) grain refiner elements. The toughness analysis was based on the V-notch Charpy impact test under temperatures of -150, -100, -50, 0, 50, 100 and 150 deg. C. A statistical analysis of the results led to the conclusion that the toughness of both alloys was influenced by temperature and grain size. The CuAlBeNbNi alloy absorbed higher impact energy than the CuAlBe alloy showing that the refining elements improved the toughness of the alloy. To confirm and complement these findings, the fracture surfaces were evaluated by stereomicroscopy. Smooth homogeneous surfaces and rough heterogonous surfaces were detected for the CuAlBeNbNi and CuAlBe alloys, respectively. Predominately brittle zones were confirmed by scanning electron microscopy in both alloys. Furthermore, to determine the phase transformation temperatures and the associated microstructures, the alloys were assessed by conventional differential scanning calorimetry (DSC) and DSC with optical microscopy.

  8. Grain size and temperature influence on the toughness of a CuAlBe shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Victor Hugo C. de, E-mail: victor.albuquerque@fe.up.pt [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Melo, Tadeu Antonio de A, E-mail: tadeu@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Gomes, Rodinei M., E-mail: gomes@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Lima, Severino Jackson G. de, E-mail: jackson@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.pt [Faculdade de Engenharia da Universidade do Porto (FEUP), Departamento de Engenharia Mecanica (DEMec)/Instituto de Engenharia Mecanica e Gestao Industrial INEGI, Rua Dr. Roberto Frias, S/N 4200-465 Porto (Portugal)

    2010-11-25

    Research highlights: {yields} This work evaluated the capacity of a CuAlBe alloy to absorb energy until rupture. {yields} The V-notch Charpy test was adopted at -150, -100, -50, 0, 50, 100 and 150 deg. C. {yields} Charpy tests were complemented by DSC, DSC with optical microscope and by SEM. {yields} First work to analyze the toughness of a CuAlBe alloy based on the Charpy test. {yields} The results are of relevant value to enhance the understanding of the CuAlBe alloy. - Abstract: This work is a study of the influence of grain size and temperature on the toughness of CuAlBe shape memory alloys with (CuAlBeNbNi) and without NbNi (CuAlBe) grain refiner elements. The toughness analysis was based on the V-notch Charpy impact test under temperatures of -150, -100, -50, 0, 50, 100 and 150 deg. C. A statistical analysis of the results led to the conclusion that the toughness of both alloys was influenced by temperature and grain size. The CuAlBeNbNi alloy absorbed higher impact energy than the CuAlBe alloy showing that the refining elements improved the toughness of the alloy. To confirm and complement these findings, the fracture surfaces were evaluated by stereomicroscopy. Smooth homogeneous surfaces and rough heterogonous surfaces were detected for the CuAlBeNbNi and CuAlBe alloys, respectively. Predominately brittle zones were confirmed by scanning electron microscopy in both alloys. Furthermore, to determine the phase transformation temperatures and the associated microstructures, the alloys were assessed by conventional differential scanning calorimetry (DSC) and DSC with optical microscopy.

  9. 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 ).

  10. Relationship between microstructure, cytotoxicity and corrosion properties of a Cu-Al-Ni shape memory alloy.

    Science.gov (United States)

    Colić, Miodrag; Rudolf, Rebeka; Stamenković, Dragoslav; Anzel, Ivan; Vucević, Dragana; Jenko, Monika; Lazić, Vojkan; Lojen, Gorazd

    2010-01-01

    Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.

  11. Moessbauer and transport studies of amorphous and icosahedral Zr-Ni-Cu-Ag-Al alloys

    International Nuclear Information System (INIS)

    Stadnik, Z.M.; Rapp, O.; Srinivas, V.; Saida, J.; Inoue, A.

    2002-01-01

    The alloy Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 in the amorphous and icosahedral states, and the bulk amorphous alloy Zr 65 Al 7.5 Ni 10 Cu 7.5 Ag 10 , have been studied with 57 Fe Moessbauer spectroscopy, electrical resistance and magnetoresistance techniques. The average quadrupole splitting in both alloys decreases with temperature as T 3/2 . The average quadrupole splitting in the icosahedral alloy is the largest ever reported for a metallic system. The lattice vibrations of the Fe atoms in the amorphous and icosahedral alloys are well described by a simple Debye model, with the characteristic Moessbauer temperatures of 379(29) and 439(28) K, respectively. Amorphous alloys Zr 65 Al 7. )5Ni 10 Cu 7.5 Ag 10 and Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 have been found to be superconducting with the transition temperature, T c , of about 1.7 K. The magnitude of Tc and the critical field slope at Tc are in agreement with previous work on Zr-based amorphous superconductors, while the low-temperature normal state resistivity is larger than typical results for binary and ternary Zr-based alloys. The resistivity of icosahedral Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 is larger than that for the amorphous ribbon of the same composition, as inferred both from direct measurements on the ribbons and from the observed magnetoresistance. However the icosahedral sample is non-superconducting in the measurement range down to 1.5 K. The results for the resistivity and the superconducting T c both suggest a stronger electronic disorder in the icosahedral phase than in the amorphous phase. (author)

  12. Effect of ageing time 200 °C on microstructure behaviour of Al-Zn-Cu-Mg cast alloys

    Directory of Open Access Journals (Sweden)

    Pratiwi Diah Kusuma

    2017-01-01

    Full Text Available Al-Zn-Cu-Mg is heat treatable alloy that can be used in many hightech applications, such as aerospace and military. The main objective of this study is to investigate the influence of ageing process in microstrucure behaviour of Al-9Zn-5Cu-4Mg cast alloy by performing SEM analysis and its correlation with hardness tests of as-cast Al-9Zn-5Cu-4Mg alloy and heat treated Al-9Zn-5Cu-4Mg cast alloy. The results show the deployment of precipitation spread over the dendrite and also the presence of second phases Mg3Zn3Al2 , Cu2FeAl7 , CuAl2, and CuMgAl2 in as-cast Al-9Zn-5Cu-4Mg alloy. The presence of all these second phases are affecting to the toughness of aluminium alloy and the presence of MgZn2 leads the impairment of hardness value of heat-treated Al-9Zn-5Cu-5Mg cast alloy.

  13. Electrical resistivity of nanocrystals in Fe-Al-Ga-P-B-Si-Cu alloy

    International Nuclear Information System (INIS)

    Pekala, K.; Jaskiewicz, P.; Nowinski, J.L.; Pekala, M.

    2003-01-01

    In new supercooled Fe 74 Al 4 Ga 2 P 11 B 4 Si 4 Cu 1 alloy the 10 nm size α-Fe(Si) nanocrystals are precipitated. Thermal stability is analyzed by the electron transport and magnetization measurements. Temperature variation of electrical resistivity of nanocrystals is determined and discussed for alloys with different initial crystalline fraction. Possible mechanism inhibiting the grain growth is presented

  14. Mechanical spectroscopy study of the Cu36Zr59Al5 and Cu54Zr40Al6 amorphous alloys

    Directory of Open Access Journals (Sweden)

    Paulo Wilmar Barbosa Marques

    2012-12-01

    Full Text Available A mechanical spectroscopy study of Cu-Zr-Al bulk metallic glasses, was performed with two types of equipment: a Kê-type inverted torsion pendulum and an acoustic elastometer, working in the frequency ranges of Hz and kHz, respectively, with a heating rate of 1 K/min. The analysis of the anelastic relaxation shows similar spectra for both types of equipment resulting in internal friction patterns that vary with temperature and are not reproducible at each thermal cycle. The normalized of the square of the frequency changes from the first to later measurement cycles. These results indicate that the specimens of Cu-Zr-Al alloys were changing by mechanical relaxation, owing to the motion of atoms or clusters in the glassy state and possible "defects" produced during the processing of alloys.

  15. 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).

  16. Thermoelastic martensite and shape memory effect in ductile Cu-Al-Mn alloys

    Science.gov (United States)

    Kainuma, R.; Takahashi, S.; Ishida, K.

    1996-08-01

    Ductile shape memory (SM) alloys of the Cu-AI-Mn system have been developed by controlling the degree of order in the β phase. Additions of Mn to the binary Cu-Al alloy stabilize the β phase and widen the single-phase region to lower temperature and lower Al contents. It is shown that Cu-Al-Mn alloys with low Al contents have either the disordered A2 structure or the ordered L21 structure with a lower degree of order and that they exhibit excellent ductility. The disordered A2 phase martensitically transforms to the disordered Al phase with a high density of twins. The martensite phase formed from the ordered L21 phase has the 18R structure. The SM effect accompanies both the A2 → Al and L21 → 18R martensitic transformations. These alloys exhibit 15 pct strain to failure, 60 to 90 pct rolling reduction without cracking, and 80 to 90 pct recovery from bend test in the martensitic condition. Experimental results on the microstructure, crystal structure, mechanical properties, and shape memory behavior in the ductile Cu-AI-Mn alloys are presented and discussed.

  17. Passivation of Cu-Zn alloy on low carbon steel electrodeposited from a pyrophosphate medium

    Science.gov (United States)

    Yavuz, Abdulcabbar; Yakup Hacıibrahimoğlu, M.; Bedir, Metin

    2018-01-01

    The motivation of this study is to understand whether zinc-based alloy also has a passivation behaviour similar to zinc itself. Cu-Zn alloys were electrodeposited potentiostatically from a pyrophosphate medium on a carbon steel electrode and their corrosion behaviours were studied. Pt and carbon steel electrodes were used in order to examine the corrosion/passivation behaviour of bare Cu, bare Zn and Cu-Zn alloy coatings. The passivation behaviour of all brass-modified electrodes having Zn content between 10% and 100% was investigated. The growth potential affects the morphology and structure of crystals. The brass coatings are more porous than their pure components. The crystalline structure of Cu-Zn alloys can be obtained by changing the deposition potential. The zinc content in brass increases when the deposition voltage applied decreases. However, the growth potential and the ratio of zinc in brass do not affect the passivation behaviour of the resulting alloys. The coatings obtained by applying different growth potentials were immersed in tap water for 24 h to compare their corrosion behaviours with carbon steel having pitting formation.

  18. Atomic bonding of precipitate and phase transformation of Al-Cu-Mg alloy

    International Nuclear Information System (INIS)

    Gao Yingjun; Hou Xianhua; Mo Qifeng; Wei Chengyang; Qin Xiaobing

    2007-01-01

    Atomic bonding of the GPB zone and S'' phase of Al-Cu-Mg alloys in early aging stage are calculated using the empirical electron theory (EET) in solid. The results show that not only the covalence bond-network is very strong in GPB zone, but the whole covalence bond energy of S'' phase is also very large, and all the primary bond-net framework of these precipitates can consolidate the matrix of alloy. Phase transformation from GPB zone to S'' phase is explained reasonably based on atomic bonding and total binding capacity of Al and Cu atoms in these precipitates

  19. Preparation of Copper (Cu)-Nickel (Ni) Alloy Thin Films for Bilayer Graphene Growth

    Science.gov (United States)

    2016-02-01

    of each sample after annealing . Transene brand APS-100 etchant is used to completely wet etch away the unmasked portion of the Cu-Ni alloy, and...morphological changes in the metal surfaces such as roughness, grain size, and crystal orientation due to the effects of annealing temperature, hydrogen...post- annealed at 1000 °C for 30 min, 40% H2, 15 Torr.............5 Fig. 6 AFM imaging of Cu:Ni alloyed films with ratios of a) 6:1 , b) 4:1, and c) 3

  20. Influence of thermo-derivative analysis conditions on microstructure of the Al-Si-Cu alloy

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2011-04-01

    Full Text Available Microstructure change of the metals and alloys as a result of variable crystallisation conditions also by mind of cooling rate changeinfluence the mechanical properties. In this work there are presented the interdependences between the cooling rate, chemical compositionand microstructure of the cast aluminium alloy Al–Si–Cu as a result of the thermo-derivative analysis, using the UMSA (UniversalMetallurgical Simulator and Analyzer device. An important tool for the microstructure evaluation of the Al type AC-AlSi7Cu3Mg alloywas the light and electron scanning microscopy technique.

  1. Nanoparticles from Cu-Zn-Al shape memory alloys physically synthesized by ion milling deposition

    Energy Technology Data Exchange (ETDEWEB)

    Pavon, Luis Alberto Lopez [Universidad Autonoma de Nuevo Leon (UANL), Nuevo Leon (Mexico); Cuellara, Enrique Lopez; Castro, Alejandro Torres; Cruza, Azael Martinez de la [Universidad Autonoma de Nuevo Leon (CIIDIT/UANL), Nuevo Leon (Mexico). Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia; Ballesteros, Carmen [Universidad Carlos III de Madrid, Madrid (Spain). Departamento de Fisica; Araujo, Carlos Jose de [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Departamento de Engenharia Mecanica

    2012-05-15

    In this research, an ion milling equipment was used to elaborate nanoparticles from Cu-Zn-Al alloys with shape memory effect. Two different compositions were used, target A: 75.22Cu-17.12Zn-7.66Al at % with an Ms of -9 deg C and target B: 76.18Cu-15.84Zn-7.98Al with an Ms of 20 degree C. Nanoparticles were characterized by High Resolution Transmission Electron Microscopy, Electron Diffraction and Energy Dispersive X-ray Spectroscopy. The obtained nanoparticles showed a small dispersion, with a size range of 3.2-3.5 nm. Their crystal structure is in good agreement with the bulk martensitic structure of the targets. In this sense, results on morphology, composition and crystal structure have indicated that it is possible to produce nanoparticles of CuZnAl shape memory alloys with martensitic structure in a single process using Ion Milling. (author)

  2. Nanoparticles from Cu-Zn-Al shape memory alloys physically synthesized by ion milling deposition

    International Nuclear Information System (INIS)

    Pavon, Luis Alberto Lopez; Cuellara, Enrique Lopez; Castro, Alejandro Torres; Cruza, Azael Martinez de la; Ballesteros, Carmen; Araujo, Carlos Jose de

    2012-01-01

    In this research, an ion milling equipment was used to elaborate nanoparticles from Cu-Zn-Al alloys with shape memory effect. Two different compositions were used, target A: 75.22Cu-17.12Zn-7.66Al at % with an Ms of -9 deg C and target B: 76.18Cu-15.84Zn-7.98Al with an Ms of 20 degree C. Nanoparticles were characterized by High Resolution Transmission Electron Microscopy, Electron Diffraction and Energy Dispersive X-ray Spectroscopy. The obtained nanoparticles showed a small dispersion, with a size range of 3.2-3.5 nm. Their crystal structure is in good agreement with the bulk martensitic structure of the targets. In this sense, results on morphology, composition and crystal structure have indicated that it is possible to produce nanoparticles of CuZnAl shape memory alloys with martensitic structure in a single process using Ion Milling. (author)

  3. Microstructure of AlSi17Cu5 alloy after overheating over liquidus temperature

    Directory of Open Access Journals (Sweden)

    J. Piątkowski

    2015-01-01

    Full Text Available The paper presents microstructure tests of alloy AlSi17Cu5. In order to disintegrate the primary grain of silicon the so-called time-temperature transformation TTT was applied which was based on overheating the liquid alloy way over the temperature Tliq., soaking in it for 30 minutes and casting it to a casting mould. It was found that such process causes the achievement of fine-crystalline structure and primary silicon crystals take up the form of pentahedra or frustums of pyramids. With the use of X-ray microanalysis and X-ray diffraction analysis the presence of intermetallic phases Al2Cu, Al4Cu9 which are the ingredients of eutectics α - AlCu - β and phase Al9Fe2Si which is a part of eutectic α - AlFeSi - β was confirmed.

  4. Phase composition of rapidly solidified Ag-Sn-Cu dental alloys

    International Nuclear Information System (INIS)

    Lecong Dzuong; Do Minh Nghiep; Nguyen van Dzan; Cao the Ha

    1996-01-01

    The phase composition of some rapidly solidified Ag-Sn-Cu dental alloys with different copper contents (6.22 wtpct) has been studied by XRD, EMPA and optical microscopy. The samples were prepared from melt-spun ribbons. The microstructure of the as-quenched ribbons was microcrystalline and consisted of the Ag sub 3 Sn, Ag sub 4 Sn, Cu sub 3 Sn and Cu sub 3 Sn sub 8 phases. Mixing with mercury (amalgamation) led to formation of the Ag sub 2 Hg sub 3, Sn sub 7 Hg and Cu sub 6 Sn sub 5 phases. The amount of copper atoms in the alloys played an important role in phase formation in the amalgams

  5. Experimental study of the spin density of metastable fcc ferromagnetic Fe-Cu alloys

    International Nuclear Information System (INIS)

    Bove, L. E.; Petrillo, C.; Sacchetti, F.; Mazzone, G.

    2000-01-01

    Magnetization density measurements on metastable Fe x Cu 1-x alloys at four compositions (x=20, 40, 50, and 60 at. %) and at 5 K temperature were carried out by means of polarized neutron diffraction. The samples were produced by high-energy ball milling and characterized by x-ray diffraction and fluorescence measurements. Additional bulk magnetization measurements were carried out on the two samples at high Fe concentration. Over the present concentration region, the Fe-Cu system is ferromagnetic and the four samples were found to be in the fcc phase. Fe-Cu is therefore a very suitable system to investigate the magnetic state of Fe in an fcc environment. Other than confirming that the Fe-Cu system is not a simple dilution alloy, the present results were compatible with a two-state model for fcc Fe--that is, two different coexisting electronic states associated with different magnetic moments and form factors

  6. L-J phase in a Cu2.2Mn0.8Al alloy

    Science.gov (United States)

    Jeng, S. C.; Liu, T. F.

    1995-06-01

    A new type of precipitate (designated L-J phase) with two variants was observed within the (DO3 + L21) matrix in a Cu2.2Mn0.8Al alloy. Transmission electron microscopy examinations indicated that the L-J phase has an orthorhombic structure with lattice parameters a = 0.413 nm, b = 0.254 nm and c = 0.728 nm. The orientation relationship between the L-J phase and the matrix is (100)L-J//(011) m , (010)L-J//(111) m and (001)L-J//(211) m . The rotation axis and rotation angle between two variants of the L-J phase are [021] and 90 deg. The L-J phase has never been observed in various Cu-Al, Cu-Mn, and Cu-Al-Mn alloy systems before.

  7. Thermal stability and primary phase of Al-Ni(Cu)-La amorphous alloys

    International Nuclear Information System (INIS)

    Huang Zhenghua; Li Jinfu; Rao Qunli; Zhou Youhe

    2008-01-01

    Thermal stability and primary phase of Al 85+x Ni 9-x La 6 (x = 0-6) and Al 85 Ni 9-x Cu x La 6 (x = 0-9) amorphous alloys were investigated by X-ray diffraction and differential scanning calorimeter. It is revealed that replacing Ni in the Al 85 Ni 9 La 6 alloy by Cu decreases the thermal stability and makes the primary phase change from intermetallic compounds to single fcc-Al as the Cu content reaches and exceeds 4 at.%. When the Ni and La contents are fixed, replacing Al by Cu increases the thermal stability but also promotes the precipitation of single fcc-Al as the primary phase

  8. Self-Formed Barrier with Cu-Mn alloy Metallization and its Effects on Reliability

    International Nuclear Information System (INIS)

    Koike, J.; Wada, M.; Usui, T.; Nasu, H.; Takahashi, S.; Shimizu, N.; Yoshimaru, M.; Shibata, H.

    2006-01-01

    Advancement of semiconductor devices requires the realization of an ultra-thin (less than 5 nm thick) diffusion barrier layer between Cu interconnect and insulating layers. Self-forming barrier layers have been considered as an alternative barrier structure to the conventional Ta/TaN barrier layers. The present work investigated the possibility of the self-forming barrier layer using Cu-Mn alloy thin films deposited directly on SiO2. After annealing at 450 deg. C for 30 min, an amorphous oxide layer of 3-4 nm in thickness was formed uniformly at the interface. The oxide formation was accompanied by complete expulsion of Mn atoms from the Cu-Mn alloy, leading to a drastic decrease in resistivity of the film. No interdiffusion was observed between Cu and SiO2, indicating an excellent diffusion-barrier property of the interface oxide

  9. Wetting phenomena of Al-Cu alloys on sapphire below 800 deg. C

    International Nuclear Information System (INIS)

    Klinter, Andreas J.; Leon-Patino, Carlos A.; Drew, Robin A.L.

    2010-01-01

    Using a modified dispensed drop method, a decrease in contact angle on sapphire from pure aluminum to low-copper-containing Al alloys (7-12 wt.%) was found; with higher copper additions θ transitions to the non-wetting regime. Atomic force microscopy on long-term samples showed a significantly increased surface roughness beneath the drop. Using high-resolution transmission electron microscopy, the reaction product at the interface was identified as CuAl 2 O 4 for Al-7Cu and Al 2 O 3 for an Al-99.99 drop. X-ray photoelectron spectroscopy further confirmed the formation of CuAl 2 O 4 under CuAl 2 drops. Spinel formation is caused by reaction of the alloy with residual oxygen in the furnace that is transported along the interface as modeled by thermodynamic simulations. The formation of CuAl 2 O 4 causes the reduced σ sl and hence the improved wettability of sapphire by low-copper-containing alloys compared to pure aluminum. The main reason for the increase in θ with higher copper contents is the increasing σ lv of the alloy.

  10. Wetting phenomena of Al-Cu alloys on sapphire below 800 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Klinter, Andreas J., E-mail: andreas.klinter@mail.mcgill.ca [Mining and Materials Engineering, McGill University, M.H. Wong Building, 3610 University Street, Montreal, QC, H3A 2B2 (Canada); Leon-Patino, Carlos A. [Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo, Apdo. Postal 888, CP 58000 Morelia, Michoacan (Mexico); Drew, Robin A.L. [Faculty of Engineering and Computer Science, Concordia University, 1455 Maisonneuve Blvd, EV 2.169, Montreal, QC, H3G 1M8 (Canada)

    2010-02-15

    Using a modified dispensed drop method, a decrease in contact angle on sapphire from pure aluminum to low-copper-containing Al alloys (7-12 wt.%) was found; with higher copper additions {theta} transitions to the non-wetting regime. Atomic force microscopy on long-term samples showed a significantly increased surface roughness beneath the drop. Using high-resolution transmission electron microscopy, the reaction product at the interface was identified as CuAl{sub 2}O{sub 4} for Al-7Cu and Al{sub 2}O{sub 3} for an Al-99.99 drop. X-ray photoelectron spectroscopy further confirmed the formation of CuAl{sub 2}O{sub 4} under CuAl{sub 2} drops. Spinel formation is caused by reaction of the alloy with residual oxygen in the furnace that is transported along the interface as modeled by thermodynamic simulations. The formation of CuAl{sub 2}O{sub 4} causes the reduced {sigma}{sub sl} and hence the improved wettability of sapphire by low-copper-containing alloys compared to pure aluminum. The main reason for the increase in {theta} with higher copper contents is the increasing {sigma}{sub lv} of the alloy.

  11. Influence of Solution Heat Treatment on Structure and Mechanical Properties of ZnAl22Cu3 Alloy

    Directory of Open Access Journals (Sweden)

    Michalik R.

    2016-09-01

    Full Text Available The influence of solution heat treatment at 385°C over 10 h with cooling in water on the structure, hardness and strength of the ZnAl22Cu3 eutectoid alloy is presented in the paper. The eutectoid ZnAl22Cu3 alloy is characterized by a dendritic structure. Dendrites are composed of a supersaturated solid solution of Al in Zn. In the interdendritic spaces a eutectoid mixture is present, with an absence of the ε (CuZn4 phase. Solution heat treatment of the ZnAl22Cu3 alloy causes the occurrence of precipitates rich in Zn and Cu, possibly ε phase. Solution heat treatment at 385°C initially causes a significant decrease of the alloy hardness, although longer solution heat treatment causes a significant increase of the hardness as compared to the as-cast alloy.

  12. Effect of Cu addition on the microstructure and mechanical properties of Al–30 wt% Zn alloy

    International Nuclear Information System (INIS)

    Abd El-Rehim, A.F.; Sakr, M.S.; El-Sayed, M.M.; Abd El-Hafez, M.

    2014-01-01

    Highlights: • This paper describes a novel work on the effect of Cu addition on the Al–30 wt% Zn alloy. • The 1 wt% Cu alloy revealed the best hardness of the alloys. • The results indicated two deformation temperature regions (below and above 548 K). - Abstract: The effect of 0.5, 1, 1.5 and 2 wt% Cu addition on the microstructure and mechanical properties of Al–30 wt% Zn alloy has been investigated by stress–strain tests carried out in the temperature range from 508 to 608 K. The work-hardening parameters of the test alloys decreased with increasing the deformation temperature and exhibited discontinuity at 548 K, resulting two deformation temperature regions, the low-temperature region (below 548 K) and high-temperature region (above 548 K). The activation energy of fracture mechanisms has been calculated and found to be 19.6 and 33.2 kJ/mol at the low and high temperature regions respectively. The operating mechanisms of work-hardening of the test alloys were confirmed by the analysis of X-ray diffraction patterns

  13. Investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al alloy with Ag and Mn additions

    International Nuclear Information System (INIS)

    Silva, R.A.G.; Paganotti, A.; Gama, S.; Adorno, A.T.; Carvalho, T.M.; Santos, C.M.A.

    2013-01-01

    The investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al, Cu-11%Al-3%Ag, Cu-11%Al-10%Mn and Cu-11%Al-10%Mn-3%Ag alloys was made using microhardness measurements, differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersion X-ray spectroscopy and magnetic moment change with applied field measurement. The results indicated that the Mn addition changes the phase stability range, the microhardness values and makes undetectable the eutectoid reaction in annealed Cu-11%Al and Cu-11%Al-3%Ag alloys while the presence of Ag does not modify the phase transformation sequence neither microhardness values of the annealed Cu-11%Al and Cu-11%Al-10%Mn alloys, but it increases the magnetic moment of this latter at about 2.7 times and decreases the rates of eutectoid and peritectoid reactions of the former. - Highlights: ► The microstructure of Cu-Al alloy is modified in the Ag presence. ► (α + γ) phase is stabilized down to room temperature when Ag is added to Cu-Al alloy. ► Ag-rich phase modifies the magnetic characteristics of Cu–Al–Mn alloy.

  14. Effect of Low Cu Amounts and Pre-Deformation on the Precipitation in Al-Mg-Si Alloys

    Science.gov (United States)

    Saito, Takeshi; Muraishi, Shinji; Marioara, Calin D.; Holmestad, Randi

    Transmission electron microscopy (TEM) studies were performed on two Al-Mg-Si alloys with low Cu additions (0.01 and 0.10 wt%) in order to investigate the effect of Cu and 10% pre-deformation on precipitate microstructure and its connection to mechanical properties. After 300 minutes aging at 190°C, fine microstructures associated with high hardness were observed in the alloy with 0.10% Cu. Pre-deformation led to heterogeneous distributions of precipitates along dislocations, causing microstructure coarsening. This effect was less pronounced in the alloy with the higher Cu amount.

  15. Structural evolutions of the mechanically alloyed Al70Cu20Fe10 ...

    Indian Academy of Sciences (India)

    The i-phase was observed only for short-time milled powders after heat treatment above 600°C. The -phase was one of the major phases in the Al70Cu20Fe10 alloy. The w-Al7Cu2Fe1 phase (w-phase) was obtained only after heat treatment of the short-time milled and unmilled samples. The present investigation ...

  16. Charge transfer, lattice distortion, and quantum confinement effects in Pd, Cu, and Pd-Cu nanoparticles; size and alloying induced modifications in binding energy

    International Nuclear Information System (INIS)

    Sengar, Saurabh K.; Mehta, B. R.; Gupta, Govind

    2011-01-01

    In this letter, effect of size and alloying on the core and valence band shifts of Pd, Cu, and Pd-Cu alloy nanoparticles has been studied. It has been shown that the sign and magnitude of the binding energy shifts is determined by the contributions of different effects; with quantum confinement and lattice distortion effects overlapping for size induced shifts in case of core levels and lattice distortion and charge transfer effects overlapping for alloying induced shifts at smaller sizes. These results are important for understanding gas molecule-solid surface interaction in metal and alloy nanoparticles in terms of valance band positions.

  17. Antibacterial effect of copper-bearing titanium alloy (Ti-Cu) against Streptococcus mutans and Porphyromonas gingivalis

    Science.gov (United States)

    Liu, Rui; Memarzadeh, Kaveh; Chang, Bei; Zhang, Yumei; Ma, Zheng; Allaker, Robert P.; Ren, Ling; Yang, Ke

    2016-07-01

    Formation of bacterial biofilms on dental implant material surfaces (titanium) may lead to the development of peri-implant diseases influencing the long term success of dental implants. In this study, a novel Cu-bearing titanium alloy (Ti-Cu) was designed and fabricated in order to efficiently kill bacteria and discourage formation of biofilms, and then inhibit bacterial infection and prevent implant failure, in comparison with pure Ti. Results from biofilm based gene expression studies, biofilm growth observation, bacterial viability measurements and morphological examination of bacteria, revealed antimicrobial/antibiofilm activities of Ti-Cu alloy against the oral specific bacterial species, Streptococcus mutans and Porphyromonas gingivalis. Proliferation and adhesion assays with mesenchymal stem cells, and measurement of the mean daily amount of Cu ion release demonstrated Ti-Cu alloy to be biocompatible. In conclusion, Ti-Cu alloy is a promising dental implant material with antimicrobial/antibiofilm activities and acceptable biocompatibility.

  18. Synthesis and characterisation of Co-Co(OH)2 composite anode material on Cu current collector for energy storage devices

    Science.gov (United States)

    Yavuz, Abdulcabbar; Yakup Hacıibrahimoğlu, M.; Bedir, Metin

    2017-04-01

    A Co-Co(OH)2 modified electrode on inexpensive Cu substrate was synthesized at room temperature and demonstrated to be a promising anode material for energy storage devices. A modified Co film was obtained potentiostatically and was then potentiodynamically treated with KOH solution to form Co(OH)2. Co-Co(OH)2 coatings were obtained and were dominated by Co(OH)2 at the oxidized side, whereas Co dominant Co-Co(OH)2 occurred at the reduced side (-1.1 V). As OH- ions were able to diffuse into (out of) the film during oxidation (reduction) and did not react with the Cu current collector, the Co-Co(OH)2 electrode can be used as an anode material in energy storage devices. Although the specific capacitance of the electrodes varied depending on thickness, the redox reaction between the modified electrode and KOH electrolyte remained the same consisting of a surface-controlled and diffusion-controlled mechanism which had a desirable fast charge and discharge property. Capacity values remained constant after 250 cycles as the film evolved. Overall capacity retention was 84% for the film after 450 scans. A specific capacitance of 549 F g-1 was obtained for the Co-Co(OH)2 composite electrode in 6 M KOH at a scan rate of 5 mV s-1 and 73% of capacitance was retained when the scan rate was increased to 100 mV s-1.

  19. Pseudo-solid-solution CuCo2O4/C nanofibers as excellent anodes for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhang, Hang; Tang, Zhiyong; Zhang, Kang; Wang, Lei; Shi, Huimin; Zhang, Guanhua; Duan, Huigao

    2017-01-01

    Ternary transition metal oxides have received intense research interest as electrode materials for lithium ion batteries, due to their high specific capacity originating from the synergic effects of multiple metal active sites. Reducing the size of metal oxides nanoparticles and dispersing these nanoparticles in carbon matrix are considering effective strategies to improve the electrochemical performance of transition metal oxides. Ternary CuCo 2 O 4 nanoclusters ultra-uniformly dispersed in carbon nanofiber matrix forming a pseudo-solid-solution structure are successfully synthesized by a facile electrospinning method followed by an appropriate annealing process. As the anodic electrode for lithium ion batteries, the pseudo-solid-solution CuCo 2 O 4 /C electrode exhibits a high reversible specific capacity, improved rate capacity and excellent cycling stability. A discharge capacity of 865 mAh g −1 is obtained at the current density of 200 mA g −1 after 400 cycles. Surprisingly, the electrode still retains about 610 mAh g −1 after 800 cycles even at the current density of 600 mA g −1 . The superior lithium storage performance of the pseudo-solid-solution CuCo 2 O 4 /C composites is mainly attributed to the unique amorphous structure. The ultrafine CuCo 2 O 4 nanoclusters uniformly dispersed in carbon matrix can buffer the volume change and improve the conductivity of the metal oxide based electrode, guaranteeing the structure stability and fast electron transfer.

  20. On the mechanical behavior of a cryomilled Al-Ti-Cu alloy

    International Nuclear Information System (INIS)

    Han, Bing Q.; Lavernia, Enrique J.; Mohamed, Farghalli A.

    2003-01-01

    The mechanical behavior of a cryomilled Al10Ti2Cu that was later extruded was investigated in compression. The data obtained show that the strength of the extruded alloy parallel to the extrusion axis is higher than that normal to the axis. Also, a comparison between the compression behavior of the alloy and its tensile behavior reveals that there is a small asymmetry of yield strength with respect to deformation mode. Examination of the microstructure of the cryomilled alloy by means of transmission electron microscopy (TEM) indicates the presence of two phases: approximately 90% nanostructured Al(Cu) phase containing a dispersion of Al 3 Ti and 10% coarse-grained Al(Cu) phase. TEM observations indicate that as a result of the extrusion process, the larger (softer) grains of the Al(Cu) phase experience severe deformation, resulting in the development of mechanical fibering. It is suggested that the presence of coarse-grained Al(Cu) 'islands' in the matrix of the nanostructured phase and their change during extrusion into elongated bands may be responsible for the anisotropy of the mechanical properties of the extruded cryomilled Al10Ti2Cu

  1. Characterization of Al-Cu-Mg-Ag Alloy RX226-T8 Plate

    Science.gov (United States)

    Lach, Cynthia L.; Domack, Marcia S.

    2003-01-01

    Aluminum-copper-magnesium-silver (Al-Cu-Mg-Ag) alloys that were developed for thermal stability also offer attractive ambient temperature strength-toughness combinations, and therefore, can be considered for a broad range of airframe structural applications. The current study evaluated Al-Cu-Mg-Ag alloy RX226-T8 in plate gages and compared performance with sheet gage alloys of similar composition. Uniaxial tensile properties, plane strain initiation fracture toughness, and plane stress tearing resistance of RX226-T8 were examined at ambient temperature as a function of orientation and thickness location in the plate. Properties were measured near the surface and at the mid-plane of the plate. Tensile strengths were essentially isotropic, with variations in yield and ultimate tensile strengths of less than 2% as a function of orientation and through-thickness location. However, ductility varied by more than 15% with orientation. Fracture toughness was generally higher at the mid-plane and greater for the L-T orientation, although the differences were small near the surface of the plate. Metallurgical analysis indicated that the microstructure was primarily recrystallized with weak texture and was uniform through the plate with the exception of a fine-grained layer near the surface of the plate. Scanning electron microscope analysis revealed Al-Cu-Mg second phase particles which varied in composition and were primarily located on grain boundaries parallel to the rolling direction. Fractography of toughness specimens for both plate locations and orientations revealed that fracture occurred predominantly by transgranular microvoid coalescence. Introduction High-strength, low-density Al-Cu-Mg-Ag alloys were initially developed to replace conventional 2000 (Al-Cu-Mg) and 7000 (Al-Zn-Cu-Mg) series aluminum alloys for aircraft structural applications [1]. During the High Speed Civil Transport (HSCT) program, improvements in thermal stability were demonstrated for candidate

  2. Influence of cathodic current density and mechanical stirring on the electrodeposition of Cu-Co alloys in citrate bath

    OpenAIRE

    Leandro Trinta de Farias; Aderval Severino Luna; Dalva Cristina Baptista do Lago; Lilian Ferreira de Senna

    2008-01-01

    Cathodic polarization curves of Cu-Co alloys were galvanostatically obtained on a platinum net, using electrolytes containing copper and cobalt sulfates, sodium citrate and boric acid (pH values ranging from 4.88 to 6.00), with different mechanical stirring conditions. In order to evaluate quantitatively the influence of the applied current density and the mechanical stirring on the cathodic efficiency, the alloy composition for the Cu-Co alloy deposition process, and the average deposition p...

  3. 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

  4. Apatite Formation and Biocompatibility of a Low Young's Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water.

    Directory of Open Access Journals (Sweden)

    Hidetatsu Tanaka

    Full Text Available Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young's modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young's modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank's solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion.

  5. Apatite Formation and Biocompatibility of a Low Young’s Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water

    Science.gov (United States)

    Tanaka, Hidetatsu; Mori, Yu; Noro, Atsushi; Kogure, Atsushi; Kamimura, Masayuki; Yamada, Norikazu; Hanada, Shuji; Masahashi, Naoya; Itoi, Eiji

    2016-01-01

    Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young’s modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young’s modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank’s solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion. PMID:26914329

  6. Electrodeposition and Characterization of Mn-Cu-Zn Alloys for Corrosion Protection Coating

    Science.gov (United States)

    Tsurtsumia, Gigla; Gogoli, David; Koiava, Nana; Kakhniashvili, Izolda; Jokhadze, Nunu; Lezhava, Tinatin; Nioradze, Nikoloz; Tatishvili, Dimitri

    2017-12-01

    Mn-Cu-Zn alloys were electrodeposited from sulphate bath, containing citrate or EDTA and their mixtures as complexing ligands. The influence of bath composition and deposition parameters on alloys composition, cathodic current efficiency and structural and electrochemical properties were studied. At a higher current density (≥ 37.5 A dm-2) a uniform surface deposit of Mn-Cu-Zn was obtained. Optimal pH of electrolyte (0.3 mol/dm3Mn2+ + 0.6 mol/dm3 (NH4)2SO4 +0.1 mol/dm3Zn2++0.005 mol/dm3 Cu2++ 0.05mol/dm3Na3Cit + 0.15mol/dm3 EDTA; t=300C; τ=20 min) for silvery, nonporous coating of Mn-Cu-Zn alloy was within 6.5-7.5; coating composition: 71-83% Mn, 6-7.8% Cu, 11.5-20% Zn, current efficiency up to 40%. XRD patterns revealed BCT (body centred tetragonal) γ-Mn solid phase solution (lattice constants a=2.68 Å c=3.59 Å). Corrosion measurements of deposited alloys were performed in aerated 3.5% NaCl solution. The corrosion current density (icorr) of the electrodeposited alloys on carbon steel was 10 times lower than corrosion rate of pure zinc and manganese coatings. Triple alloy coatings corrosion potential (Ecorr = -1140 mV vs. Ag/AgCl) preserved negative potential value longer (more than three months) compared to carbon steel substrate (Ecorr = -670 mV vs. Ag/AgCl). Tafel polarization curves taken on Mn-Cu-Zn alloy coating in aerated 3.5% NaCl solution did not show a typical passivation behaviour which can be explained by formation oflow solubility of adherent corrosion products on the alloy surface. Corrosion test of Mn-Cu-Zn electrocoating in chlorine environment shows that it is the best cathodic protective coating for a steel product.

  7. High conductivity Be-Cu alloys for fusion reactors

    International Nuclear Information System (INIS)

    Lilley, E.A.; Adachi, Takao; Ishibashi, Yoshiki

    1995-01-01

    The optimum material has not yet been identified. This will result in heat from plasma to the first wall and divertor. That is, because of cracks and melting by thermal power and shock. Today, it is considered to be some kinds of copper, alloys, however, for using, it must have high conductivity. And it is also needed another property, for example, high strength and so on. We have developed some new beryllium copper alloys with high conductivity, high strength, and high endurance. Therefore, we are introducing these new alloys as suitable materials for the heat sink in fusion reactors

  8. Removal of lead from the industrial and synthetic Cu-Pb-Fe alloy with argon barbotage

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2012-01-01

    Full Text Available Results of research on removal of lead from synthetic and industrial Cu-Pb-Fe alloy with argon barbotage are presented. For examinations was taken a synthetic alloy and industrial alloy coming “Glogow II” Copperworks. As basic research equipment was used a pipe resistance furnace enabling heating of samples up to 1 473 K. Examinations were made in 2 test series. The 1 series was performed on the synthetic alloy, while in 2 series was used an industrial alloy. All series were conducted at 1 473 K and with gas fl ow 5,55•10-6, 6,94•10-6, 8,33•10-6, 9,72•10-6 m3•s-1.

  9. Al-Cu-Li and Al-Mg-Li alloys: Phase composition, texture, and anisotropy of mechanical properties (Review)

    Science.gov (United States)

    Betsofen, S. Ya.; Antipov, V. V.; Knyazev, M. I.

    2016-04-01

    The results of studying the phase transformations, the texture formation, and the anisotropy of the mechanical properties in Al-Cu-Li and Al-Mg-Li alloys are generalized. A technique and equations are developed to calculate the amounts of the S1 (Al2MgLi), T1 (Al2CuLi), and δ' (Al3Li) phases. The fraction of the δ' phase in Al-Cu-Li alloys is shown to be significantly higher than in Al-Mg-Li alloys. Therefore, the role of the T1 phase in the hardening of Al-Cu-Li alloys is thought to be overestimated, especially in alloys with more than 1.5% Li. A new model is proposed to describe the hardening of Al-Cu-Li alloys upon aging, and the results obtained with this model agree well with the experimental data. A texture, which is analogous to that in aluminum alloys, is shown to form in sheets semiproducts made of Al-Cu-Li and Al-Mg-Li alloys. The more pronounced anisotropy of the properties of lithium-containing aluminum alloys is caused by a significant fraction of the ordered coherent δ' phase, the deformation mechanism in which differs radically from that in the solid solution.

  10. A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties.

    Science.gov (United States)

    Ren, Ling; Memarzadeh, Kaveh; Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang; Ren, Guogang; Allaker, Robert P; Yang, Ke

    2016-10-01

    The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Comparison of GRCop-84 to Other High Thermal Conductive Cu Alloys

    Science.gov (United States)

    deGroh, Henry C., III; Ellis, David L.; Loewenthal, William S.

    2007-01-01

    The mechanical properties of five copper alloys (GRCop-84, AMZIRC, GlidCop Al-15, Cu-1Cr-0.1Zr, Cu-0.9Cr) competing in high temperature, high heat flux applications such as rocket nozzles, were compared. Tensile, creep, thermal expansion, and compression tests are presented. Tests were done on as-received material, and on material which received a simulated brazing heat treatment at 935 C. The 935 C heat treatment weakened AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr, and the strength of as-received AMZIRC dropped precipitously as test temperatures exceeded 500 C. The properties of GlidCop Al-15 and GRCop-84 were not significantly affected by the 935 C heat treatment. Thus GRCop-84 is better than AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr at temperatures greater than 500 C. Ductility was lowest in GlidCop Al-15 and Cu-0.9Cr. The creep properties of GRCop-84 were superior to those of brazed AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr. At equivalent rupture life and stress, GRCop-84 had a 150 C temperature advantage over brazed AMZIRC; for equivalent rupture life and temperature GRCop-84 was two times stronger. The advantages of GRCop-84 over GlidCop Al-15 associated with ease of processing were confirmed by GlidCop s marginal ductility. In the post brazed condition, GRCop-84 was found to be superior to the other alloys due to its greater strength and creep resistance (compared to AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr) and ductility (compared to GlidCop Al-15)

  12. Effect of Cooling Rate on the Longitudinal Modulus of Cu3Sn Phase of Ag-Sn-Cu Amalgam Alloy (Part II

    Directory of Open Access Journals (Sweden)

    R. H. Rusli

    2015-10-01

    Full Text Available Effects of cooling rate (at the time of solidification on the elastic constants of Cu3Sn phase of Ag-Sn-Cu dental amalgam alloy were studied. In this study, three types of alloys were made, with the composition Cu-38-37 wt% Sn by means of casting, where each alloy was subjected to different cooling rate, such as cooling on the air (AC, air blown (AB, and quenched in the water (WQ. X-ray diffraction, metallography, and Scanning Electron Microscopy with Energy Dispersive Spectroscopy studies of three alloys indicated the existence of Cu3Sn phase. Determination of the modulus of elasticity of Cu3Sn (ε phase was carried out by the measurement of longitudinal and transversal waves velocity using ultrasonic technique. The result shows that Cu3Sn (ε phase on AC gives higher modulus of elasticity values than those of Cu3Sn (ε on AB and WQ. The high modulus of elasticity value will produce a strong Ag-Sn-Cu dental amalagam alloy.

  13. Texture Formation of Electroplated Nickel and Nickel Alloy on Cu Substrate

    International Nuclear Information System (INIS)

    Lee, Hee Gyoun; Hong, Gye Won; Kim, Jae Geun; Lee, Sun Wang; Kim, Ho Jin

    2006-01-01

    Nickel and nickel-tungsten alloy were electroplated on a cold rolled and heat treated copper(Cu) substrate. 4 mm-thick high purity commercial grade Cu was rolled to various thicknesses of 50, 70, 100 and 150 micron. High reduction ratio of 30% was applied down to 150 micron. Rolled texture was converted into cube texture via high temperature heat treatment at 400-800 degrees C. Grain size of Cu was about 50 micron which is much smaller compared to >300 micron for the Cu prepared using smaller reduction pass of 5%. 1.5 km-long 150 micron Cu was fabricated with a rolling speed of 33 m/min and texture of Cu was uniform along length. Abnormal grain growth and non-cube texture appeared for the specimen anneal above 900 degrees C. 1-10 micron thick Ni and Ni-W film was electroplated onto an annealed cube-textured Cu or directly on a cold rolled Cu. Both specimens were annealed and the degree of texture was measured. For electroplating of Ni on annealed Cu, Ni layer duplicated the cube-texture of Cu substrate and the FWHM of in plane XRD measurement for annealed Cu layer and electroplated layer was 9.9 degree and 13.4 degree, respectively. But the FWHM of in plane XRD measurement of the specimen which electroplated Ni directly on cold rolled Cu was 8.6 degree, which is better texture than that of nickel electroplated on annealed Cu and it might be caused by the suppression of secondary recrystallization and abnormal grain growth of Cu at high temperature above 900 degrees C by electroplated nickel.

  14. On the evolution of Cu-Ni-rich bridges of Alnico alloys with tempering

    Energy Technology Data Exchange (ETDEWEB)

    Fan, M. [Department of Materials Science and Engineering, North Carolina State University, Campus Box 7907, Raleigh, NC 27695-7907 (United States); Liu, Y. [Department of Materials Science and Engineering, North Carolina State University, Campus Box 7907, Raleigh, NC 27695-7907 (United States); Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC 27695 (United States); Jha, Rajesh; Dulikravich, George S. [Departments of Mechanical and Materials Engineering, MAIDROC, Florida International University, EC3462, 10555 West Flagler Street, Miami, FL 33174 (United States); Schwartz, J.; Koch, C.C. [Department of Materials Science and Engineering, North Carolina State University, Campus Box 7907, Raleigh, NC 27695-7907 (United States)

    2016-12-15

    Tempering is a critical step in Alnico alloy processing, yet the effects of tempering on microstructure have not been well studied. Here we report these effects, and in particular the effects on the Cu-Ni bridges. Energy-dispersive X-ray spectroscopy (EDS) maps and line scans show that tempering changes the elemental distribution in the Cu-Ni bridges, but not the morphology and distribution of Cu-bridges. The Cu concentration in the Cu-Ni bridges increases after tempering while other element concentrations decrease, especially Ni and Al. Furthermore, tempering sharpens the Cu bridge boundaries. These effects are primarily related to the large 2C{sub 44}/(C{sub 11}−C{sub 12}) ratio for Cu, largest of all elements in Alnico. In addition, the Ni-Cu loops around the α{sub 1} phases become inconspicuous with tempering. The diffusion of Fe and Co to the α{sub 1} phase during tempering, which increases the difference of saturation magnetization between the α{sub 1} and α{sub 2} phases, is observed by EDS. In summary, α{sub 1}, α{sub 2} and Cu-bridges are concentrated with their major elements during tempering which improves the magnetic properties. The formation of these features formed through elemental diffusion is discussed via energy theories. - Highlights: • Tempering changes the elemental distribution in the Cu-Ni bridges, but not morphology. • Cu concentration in the Cu-Ni bridges increases after tempering while others decrease. • These effects are related to the large 2C{sub 44}/(C{sub 11}−C{sub 12}) ratio for Cu. • The Ni-Cu loops around the α{sub 1} phases become inconspicuous with tempering. • The diffusion of Fe and Co to the α{sub 1} phase during tempering is observed by EDS.

  15. Kinetic study of the annealing reactions in Cu-Ni-Fe alloys

    International Nuclear Information System (INIS)

    Donoso, E.

    2014-01-01

    The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC) and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi 3 phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi 3 phase. (Author)

  16. Cu particles decorated pomegranate-structured SnO2@C composites as anode for lithium ion batteries with enhanced performance

    International Nuclear Information System (INIS)

    Wen, WeiWei; Zou, Mingzhong; Feng, Qian; Li, Jiaxin; Guan, Lunhui; Lai, Heng; Huang, Zhigao

    2015-01-01

    In this paper, homogeneous composites of pomegranate-structured SnO 2 @C/Cu have been prepared by a simple hydrothermal reaction coupled with wet-chemical reduction, and directly used as anode materials for lithium ion batteries (LIBs). These SnO 2 @C/Cu anodes with an unique architecture show good LIB performance with a capacity of 660 mAh g −1 tested at 600 mA g −1 after 50 cycles and good rate performance at room temperature. Compared with the pure SnO 2 and SnO 2 @C, SnO 2 @C/Cu anodes exhibit much better low-temperature electrochemical performance including reversible capacity, cycling performance, and rate performance. The good LIB performance of SnO 2 @C/Cu anodes should be associated with carbon shell and the conducting Cu particles. This unique configuration can prevent the agglomeration of active materials and facilitate electron conduction especially at a relative low temperature, and obtain the capacity stability in cycling process for LIBs.

  17. The effect of pretreatment, welding technique and filter alloys in TIG welding of AlLiCu alloys. Pt. 2

    International Nuclear Information System (INIS)

    Krueger, U.; Neye, G.

    1989-01-01

    Previous publications on TIG welding on recently developed AlLiCu alloys point to unsatisfactory results if one proceeds in the usual way. In this report, the conditions are shown for producing welds with few pores with the aid of TIG welding using usual production methods. After reporting on investigations with argon as the cover gas in the first part of the report, this part is concerned with experiments in which helium was used as the cover gas. (orig.) [de

  18. Studies of the development and characterization of the Cu-Ni-Pt and Cu-Ni-Sn alloys for electro-electronic uses

    International Nuclear Information System (INIS)

    Silva, Luis Carlos Elias da

    2006-01-01

    The Cu and its alloys have different applications in the owed modern society the excellent electric properties, thermal conductivity, resistance to the corrosion and other properties. These applications can be in valves, pipes, pots for absorption of solar energy, radiators for automobiles, current driver, electronic driver, thermostats elements and structural parts of nuclear reactors, as, for example, reels for field toroidal for a reactor of nuclear coalition. The alloys used in nuclear reactors, we can highlight Cu-Be, Cu-Sn and Cu-Pt. Ni and Co frequently are added to the Cu alloys so that the solubility is moved for temperatures more elevated with relationship to the binary systems of Cu-Sn and Cu-Pt. The addition of Ni-Pt or Ni-Sn to the Cu in the same or inferior percentages to 1,5% plus thermomechanical treatments changes the properties of the copper. We studied the electric conductivity and hardness Vickers of the Cu-Ni-Pt and Cu-Ni-Sn and compared with the electrolytic Cu. In the proposed flowcharts, breaking of the obtaining of the ingot, we proceeded with thermo mechanical treatments. (author)

  19. Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

    Energy Technology Data Exchange (ETDEWEB)

    Agraval, Pavel; Turchanin, Mikhail [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Dreval, Liya [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Materials Science International Services GmbH (MSI), Stuttgart (Germany)

    2016-12-15

    In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x{sub Cu}/x{sub Fe} = 3/1, 1/1 at x{sub Hf} = 0-0.47 and along the section x{sub Cu}/x{sub Fe} = 1/3 at x{sub Hf} = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ{sub mix} anti H{sub Hf}{sup ∞}, are (-122 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 3/1), (-106 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/1), and (-105 ± 2) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.

  20. Metal oxides and lithium alloys as anode materials for lithium-ion batteries

    CSIR Research Space (South Africa)

    Kebede, M

    2016-07-01

    Full Text Available -generation anode materials for lithium–ion batteries with high prospect of replacing graphite. Most of these anode materials have higher specific capacities between the range of 600-1000 mA h g(sup-1) compared with 340 mA h g(sup-1) of graphite. These high...

  1. Is Cu60Ti10Zr30 a bulk glass-forming alloy?

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saida, J.; Kato, H.

    2003-01-01

    . Nanocrystals with a significant volume fraction are randomly distributed in the amorphous matrix. The copper element is enriched in nanocrystals while a slightly high zirconium content is found in the matrix. We classify that the Cu60Ti10Zr30 alloy prepared by both of the aforementioned methods...

  2. The response of macrophages to a Cu-Al-Ni shape memory alloy.

    Science.gov (United States)

    Colić, Miodrag; Tomić, Sergej; Rudolf, Rebeka; Anz