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)

Reduction of crystallization temperature of the Nd-Fe-B thin films by Cu addition

International Nuclear Information System (INIS)

Ma Yungui; Yang Zheng; Matsumoto, M.; Morisako, A.; Takei, S.

2004-01-01

Nonmagnetic Cu element has been doped into the sputtered Nd-Fe-B thin films. It is found that the introduction of suitable amount of copper atoms could reduce the crystallization temperature of the 2:14:1 phase by near 100 deg. C, compared with that without Cu. For the 15 nm Nd 16 Fe 70.2 Cu 1.8 B 12 film deposited at 340 deg. C, perpendicular coercivity and remanent magnetization ratio of 350 kA/m and 0.96 have been successfully obtained. Cu addition would lead to the grain growth, but the average grain size in the films could be greatly decreased through lowering the deposition temperature. These results are compared with those found in the fabrication of FePtCu films

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.

Soft magnetic properties of hybrid ferromagnetic films with CoFe, NiFe, and NiFeCuMo layers

Energy Technology Data Exchange (ETDEWEB)

Choi, Jong-Gu [Eastern-western Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Hwang, Do-Guwn [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Rhee, Jang-Roh [Dept. of Physics, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Lee, Sang-Suk, E-mail: sslee@sangji.ac.kr [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of)

2011-09-30

Two-layered ferromagnetic alloy films (NiFe and CoFe) with intermediate NiFeCuMo soft magnetic layers of different thicknesses were investigated to understand the relationship between coercivity and magnetization process by taking into account the strength of hard-axis saturation field. The thickness dependence of H{sub EC} (easy-axis coercivity), H{sub HS} (hard-axis saturation field), and {chi} (susceptibility) of the NiFeCuMo thin films in glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared using the ion beam deposition method was determined. The magnetic properties (H{sub EC}, H{sub HS}, and {chi}) of the ferromagnetic CoFe, NiFe three-layers with an intermediate NiFeCuMo super-soft magnetic layer were strongly dependent on the thickness of the NiFeCuMo layer.

Changes of microstructure and magnetic properties of Nd-Fe-B sintered magnets by doping Al-Cu

International Nuclear Information System (INIS)

Ni Junjie; Ma Tianyu; Yan Mi

2011-01-01

The microstructural and magnetic properties of Al 100-x Cu x (15at%≤x≤45 at%) doped Nd-Fe-B magnets were studied. The distribution and alloying effects of Cu or Al on the intergranular microstructure were investigated by thermodynamic analysis, differential scanning calorimetery and microscopy techniques. It was observed that when the Cu content of Al 100x Cu x exceeds to 25 at%, the (Pr, Nd)Cu and CuAl 2 phases form in these magnets. The formation of (Pr, Nd)Cu phase depends on the negative formation enthalpy of (Pr, Nd)Cu and the exclusive distribution of Cu in the intergranular regions. The eutectic reaction between (Pr, Nd)Cu phase and (Pr, Nd) occurs at 480 deg. C, which forms the liquid phase that dissolves the (Pr, Nd) 2 Fe 14 B surface irregularities and thus increases the quantities of (Pr, Nd)-rich phase at the grain boundaries. These changes benefit the grain boundary microstructure, especially the distribution of (Pr, Nd)-rich phase, which effectively improves the intrinsic coercivity i H c due to the decreases of exchange coupling between the (Pr, Nd) 2 Fe 14 B grains. - Highlights: → Cu/Al effects on Nd-Fe-B structure depend on their distribution/alloying behaviors. → Cu exclusively distributes in grain boundaries different from Al and has negative mixing heat with Nd. → (Pr,Nd)Cu phase besides CuAl 2 forms in grain boundaries with Cu content increase. → (Pr,Nd)Cu phases optimize microstructure and increase magnetic properties.

RbCuFe(PO42

Directory of Open Access Journals (Sweden)

Mongi Ben Amara

2013-08-01

Full Text Available A new iron phosphate, rubidium copper(II iron(III bis(phosphate, RbCuFe(PO42, has been synthesized as single crystals by the flux method. This compound is isostructural with KCuFe(PO42 [Badri et al. (2011, J. Solid State Chem. 184, 937–944]. Its structure is built up from Cu2O8 units of edge-sharing CuO5 polyhedra, interconnected by FeO6 octahedra through common corners to form undulating chains that extend infinitely along the [011] and [01-1] directions. The linkage of such chains is ensured by the PO4 tetraedra and the resulting three-dimensional framework forms quasi-elliptic tunnels parallel to the [101] direction in which the Rb+ cations are located.

Effect of interface intermixing on giant magnetoresistance in NiFe/Cu and Co/NiFe/Co/Cu multilayers

International Nuclear Information System (INIS)

Nagamine, L.C.C.M.; Biondo, A.; Pereira, L.G.; Mello, A.; Schmidt, J.E.; Chimendes, T.W.; Cunha, J.B.M.; Saitovitch, E.B.

2003-01-01

This article reports on the important influence of the spontaneously built-in paramagnetic interfacial layers on the magnetic and magnetoresistive properties of NiFe/Cu and Co/NiFe/Co/Cu multilayers grown by magnetron sputtering. A computational simulation, based on a semiclassical model, has been used to reproduce the variations of the resistivity and of the magnetoresistance (MR) amplitude with the thickness of the NiFe, Cu, and Co layers. We showed that the compositionally intermixed layers at NiFe/Cu interfaces, which are paramagnetic, reduce the flow of polarized electrons and produce a masking on the estimated mean-free path of both types of electrons due to the reduction of their effective values, mainly for small NiFe thickness. Moreover, the transmission coefficients for the electrons decrease when Fe buffer layers are replaced by NiFe ones. This result is interpreted in terms of the variations of the interfacial intermixing and roughness at the interfaces, leading to an increase of the paramagnetic interfacial layer thickness. The effect provoked by Co deposition at the NiFe 16 A/Cu interfaces has also been investigated. The maximum of the MR amplitudes was found at 5 A of Co, resulting in the quadruplication of the MR amplitude. This result is partially attributed to the interfacial spin-dependent scattering due to the increase of the magnetic order at interfaces. Another effect observed here was the increase of the spin-dependent scattering events in the bulk NiFe due to a larger effective NiFe thickness, since the paramagnetic interfacial layer thickness is decreased

The growth of Fe clusters over graphene/Cu(111)

International Nuclear Information System (INIS)

Takahashi, Keisuke

2015-01-01

The growth of Fe clusters up to nine atoms over graphene/Cu(111) is investigated within the density functional theory. Graphene is weakly physisorbed on Cu(111) through van der Waals force. The structures of Fe clusters over graphene/Cu(111) grow differently compared to gas-phase Fe clusters where Fe clusters are predicted to form towards a pyramid-like structure on graphene/Cu(111). The graphene is negatively charged upon the adsorption of Fe clusters as a result of charge transfer from Fe to graphene. Despite the fact that the electronic structure of graphene is affected by Fe clusters, magnetic moment of Fe clusters over graphene/Cu(111) remains relatively high. This suggests that graphene can be a potential substrate for supporting Fe clusters towards applications in magnetism and catalysis. (paper)

Developing an electrochemical sensor based on a carbon paste electrode modified with nano-composite of reduced graphene oxide and CuFe2O4 nanoparticles for determination of hydrogen peroxide.

Science.gov (United States)

Benvidi, Ali; Nafar, Mohammad Taghi; Jahanbani, Shahriar; Tezerjani, Marzieh Dehghan; Rezaeinasab, Masoud; Dalirnasab, Sudabeh

2017-06-01

In this paper, a highly sensitive voltammetric sensor based on a carbon paste electrode with CuFe 2 O 4 nanoparticle (RGO/CuFe 2 O 4 /CPE) was designed for determination of hydrogen peroxide (H 2 O 2 ). The electrocatalytic reduction of H 2 O 2 was examined using various techniques such as cyclic voltammetry (CV), chronoamperometry, amperometry and differential pulse voltammetry (DPV). CuFe 2 O 4 nanoparticles were synthesized by co-precipitation method and characterized with scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) techniques. Then, a high conductive platform based on a carbon paste electrode modified with RGO and CuFe 2 O 4 nanoparticles was prepared as a suitable platform for determination of hydrogen peroxide. Under the optimum conditions (pH5), the modified electrode indicated a fast amperometric response of determination of hydrogen peroxide. Also, the peak current of differential pulse voltammetry (DPV) of hydrogen peroxide is increased linearly with its concentration in the ranges of 2 to 10μM and 10 to 1000μM. The obtained detection limit for hydrogen peroxide was evaluated to be 0.064μM by DPV. The designed sensor was successfully applied for the assay of hydrogen peroxide in biological and pharmaceutical samples such as milk, green tea, and hair dye cream and mouthwash solution. Copyright © 2017. Published by Elsevier B.V.

Fe and Cu isotope mass balances in the human body

Science.gov (United States)

Balter, V.; Albarede, F.; Jaouen, K.

2011-12-01

The ranges of the Fe and Cu isotope compositions in the human body are large, i.e. ~3% and ~2%, respectively. Both isotopic fractionations appear to be mainly controlled by redox conditions. The Fe and Cu isotope compositions of the tissues analyzed so far plot on a mixing hyperbolae between a reduced and an oxidized metals pools. The reduced metals pool is composed by erythrocytes, where Fe is bounded to hemoglobin as Fe(II) and Cu to superoxide-dismutase as Cu(I). The oxidized metals pool is composed by hepatocytes, where Fe and Cu are stored as Fe(III) ferritin and as Cu(II) ceruloplasmine, respectively. The position of each biological component in the δ56Fe-δ65Cu diagram therefore reflects the oxidation state of Fe and Cu of the predominant metal carrier protein and allows to quantify Fe and Cu fluxes between organs using mass balance calculations. For instance, serum and clot Fe and Cu isotope compositions show that current biological models of erythropoiesis violates mass conservation requirements, and suggest hidden Fe and Cu pathways during red blood cells synthesis. The results also show that a coupled Fe-Cu strong gender isotopic effect is observed in various organs. The isotopic difference between men and women is unlikely to be due to differential dietary uptake or endometrium loss, but rather reflects the effect of menstrual losses and a correlative solicitation of hepatic stores. We speculate that thorough studies of the metabolism of stable isotopes in normal conditions is a prerequisite for the understanding of the pathological dysregulations.

Note: Erosion of W-Ni-Fe and W-Cu alloy electrodes in repetitive spark gaps.

Science.gov (United States)

Wu, Jiawei; Han, Ruoyu; Ding, Weidong; Qiu, Aici; Tang, Junping

2018-02-01

A pair of W-Ni-Fe and W-Cu electrodes were tested under 100 kA level pulsed currents for 10 000 shots, respectively. Surface roughness and morphology characteristics of the two pairs of electrodes were obtained and compared. Experimental results indicated cracks divided the W-Cu electrode surface to polygons while the W-Ni-Fe electrode surface remained as a whole with pits and protrusions. Accordingly, the surface roughness of W-Ni-Fe electrodes increased to ∼3 μm while that of W-Cu electrodes reached ∼7 μm at the end of the test. The results reveal that the W-Ni-Fe alloy has a better erosion resistance and potential to be further applied in spark gaps.

NH3-SCR on Cu, Fe and Cu + Fe exchanged beta and SSZ-13 catalysts: Hydrothermal aging and propylene poisoning effects

International Nuclear Information System (INIS)

Wang, Aiyong; Wang, Yilin; Walter, Eric D.; Washton, Nancy M.

2017-01-01

Cu, Fe and Cu + Fe ion exchanged Beta and SSZ-13 catalysts were prepared by solution ion exchange using commercial NH 4 /Beta, and NH 4 /SSZ-13 that was prepared in-house. To study hydrothermal aging effects, Beta supported catalysts were aged hydrothermally at 700 °C and SSZ-13 supported catalysts were aged at 750 °C. In order to reveal the effects of Fe addition in the co-exchanged catalysts, these catalysts were characterized by means of powder X-ray diffraction (XRD), N 2 adsorption-desorption, electron paramagnetic resonance (EPR), 27 Al-nuclear magnetic resonance ( 27 Al-NMR) and propylene coking followed with temperature programmed reaction (TPR), and further tested with standard NH 3 -SCR with and without the presence of propylene. Collectively, the catalyst characterizations and reaction testing indicated minor beneficial effects of Fe addition in Cu,Fe/Beta, where NH 3 -SCR activity, N 2 selectivity and hydrothermal stability were all slightly improved. In contrast, Fe addition did not show apparent beneficial effects in low-temperature SCR for the Cu,Fe/SSZ-13 case. In conclusion, at elevated reaction temperatures, however, the presence of Fe indeed considerably improved NO conversion and N 2 selectivity for the hydrothermally aged Cu,Fe/SSZ-13 catalyst in the presence of propylene.

Research progress in photolectric materials of CuFeS2

Science.gov (United States)

Jing, Mingxing; Li, Jing; Liu, Kegao

2018-03-01

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

Facile preparation of magnetic mesoporous Fe_3O_4/C/Cu composites as high performance Fenton-like catalysts

International Nuclear Information System (INIS)

Li, Keyan; Zhao, Yongqin; Janik, Michael J.; Song, Chunshan; Guo, Xinwen

2017-01-01

Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe_3O_4/C/Cu was obtained by calcining tartrate under N_2. • Fe_3O_4/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe_2O_3/CuO and α-Fe_2O_3/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe_3O_4/C/Cu was obtained by calcining the tartrate precursor under N_2 atmosphere at 500 °C. The Fe_3O_4/C/Cu composite possessed mesoporous structure and large surface area up to 133 m"2 g"−"1. The Fenton catalytic performance of Fe_3O_4/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe"3"+ to Fe"2"+, which accelerated the Fe"3"+/Fe"2"+ cycles and favored H_2O_2 decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe"3"+ and Cu"2"+, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe_3O_4/C/Cu-H_2O_2 system, and MB (100 mg L"−"1) was nearly removed within 60 min. The Fe_3O_4/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile, cheap and green method for the synthesis of mesoporous composites as excellent Fenton-like catalysts, without any additional reductants or organic

Rapid thermal annealing of FePt and FePt/Cu thin films

Energy Technology Data Exchange (ETDEWEB)

Brombacher, Christoph

2011-01-10

Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

Preparation And Characterization of Cu-Fe/ TiO2 Photocatalyst for Visible Light Deep Desulfurization

International Nuclear Information System (INIS)

Hayyiratul Fatimah Mohd Zaid; Kait, C.F.; Mohamed Ibrahim Abdul Mutalib

2016-01-01

A photooxidative system for deep desulfurization of model diesel fuel was explored. Nanoparticles of anatase titania (TiO 2 ) were synthesized via sol-gel hydrothermal method. The TiO 2 was further modified with bimetallic Cu-Fe using wet-impregnation method followed by calcination process in order to extend the activity region of the photocatalyst to visible-light. A series of bimetallic 2.2 wt % Cu-Fe/ TiO 2 photocatalysts with different Cu:Fe mass compositions were characterized for their physical, chemical and optical properties using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), diffuse reflectance UV-visible spectroscopy (DR-UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR) and Brunauer-Emmet-Teller (BET) surface area analysis. The performance of the photocatalysts was evaluated for photooxidation of dibenzothiophene (DBT) as the sulfur species from model oil in the presence of hydrogen peroxide, H 2 O 2 under 500 W visible light illumination. The highest sulfur conversion of 82.36 % was observed for photocatalyst with 10:1Cu:Fe mass composition. (author)

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.

Role of Cu During Sintering of Fe0.96Cu0.04 Nanoparticles

Science.gov (United States)

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

2018-04-01

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

X-ray diffraction study of chalcopyrite CuFeS2, pentlandite (Fe,Ni)9S8 and Pyrrhotite Fe1-xS obtained from Cu-Ni orebodies

International Nuclear Information System (INIS)

Nkoma, J.S.; Ekosse, G.

1998-05-01

The X-ray Diffraction (XRD) technique is applied to study five samples of Cu-Ni orebodies, and it is shown that they contain chalcopyrite CuFeS 2 as the source of Cu, pentlandite (Fe,Ni) 9 S 8 as the source of Ni and pyrrhotite Fe 1-x S as a dominant compound. There are also other less dominant compounds such as bunsenite NiO, chalcocite Cu 2 S, penrosite (Ni, Cu)Se 2 and magnetite Fe 3 O 4 . Using the obtained XRD data, we obtain the lattice parameters for tetragonal chalcopyrite as a=b=5.3069A and c=10.3836A, cubic pentlandite as a=b=c=10.0487A, and hexagonal pyrrhotite as a=b=6.8820A and c=22.8037A. (author)

Formation of modified TbCu{sub 7} and Th{sub 2}Zn{sub 17} type structures during annealing of mechanical-alloyed Sm-Fe powders

Energy Technology Data Exchange (ETDEWEB)

Teresiak, A.; Kubis, M.; Mattern, N.; Wolf, M.; Mueller, K.-H. [Inst. fuer Festkoerper- und Werkstofforschung, Dresden (Germany)

1998-06-26

Compounds with the nominal composition near Sm{sub 2}Fe{sub 17} were prepared by mechanical alloying starting from the elemental powders and subsequent annealing at temperatures, T{sub A}, between 600 C and 900 C. For crystal structure investigations of the non-equilibrium phases formed at various temperatures, XRD methods with following Rietveld analysis were applied. For T{sub A} between 600 C and 750 C a modified TbCu{sub 7}-type structure of space group P6/mmm was found, in which the Fe(2c) site is replaced by the partially (1/3) and randomly occupied Fe(6l) site. Its approximate composition is SmFe{sub 8.8-9.0}. For T{sub A} between 800 C to 900 C a disordered modified Th{sub 2}Zn{sub 17} structure (space group R anti 3m) was found that is formed by introducing additional randomly occupied Fe (6c) and Sm(3a) positions, respectively. The degree of order of Sm atoms and Fe-dumbbells along the c-direction increases with increasing T{sub A}. A decrease in the Fe concentration in the cell is observed for increasing T{sub A}. The completely ordered stoichiometric Th{sub 2}Zn{sub 17}-type structure could not be reached by annealing samples prepared from the ball-milled elemental powders. (orig.) 20 refs.

The geochemical profile of Mn, Co, Cu and Fe in Kerteh Mangrove Forest, Terengganu

International Nuclear Information System (INIS)

Kamaruzzaman, B.Y.; Antotina, A.; Airiza, Z.; Syalindran, S.; Ong, M.C.

2007-01-01

The geochemical profile of Kerteh mangrove sediments was analyzed for the vertical and horizontal distribution. The 100 cm core sediment sample and 15 surface sediments samples were taken from the field. The geochemical elements of Mn, Co, Cu and Fe of the sediments were analyzed. Geochemical proxy of Mn, Co, Cu and Fe were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The mean concentrations of Mn, Co, Cu and Fe for the vertical distribution were 210.18 μg/ g, 15.55 μg/ g, 43.65 μg/ g and 1.88 μg/ g respectively. on the other hand, the mean concentrations of the geochemical elements for horizontal distributions were 230.50 μg/ g for Mn, 17.57 μg/ g for Co, 43.381 μg/ g for Cu and 2.93 μg/ g for Fe. Enrichment factor and normalization was used to point out the level of pollution. The EF and the normalization indicated that all the geochemical elements were from the natural sources. (author)

Anomalous superconducting spin-valve effect in NbN/FeN/Cu/FeN/FeMn multilayers

Energy Technology Data Exchange (ETDEWEB)

Hwang, Tae Jong; Kim, Dong Ho [Yeungnam University, Gyeongsan (Korea, Republic of)

2017-09-15

We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

Science.gov (United States)

Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

2011-12-01

Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

Coercivity Recovery Effect of Sm-Fe-Cu-Al Alloy on Sm2Fe17N3 Magnet

Science.gov (United States)

Otogawa, Kohei; Asahi, Toru; Jinno, Miho; Yamaguchi, Wataru; Takagi, Kenta; Kwon, Hansang

2018-03-01

The potential of a Sm-Fe-Cu-Al binder for improvement of the magnetic properties of Sm2Fe17N3 was examined. Transmission electron microscope (TEM) observation of a Sm-Fe-Cu-Al alloy-bonded Sm2Fe17N3 magnet which showed high coercivity revealed that the Sm-Fe-Cu-Al alloy had an effect of removing the surface oxide layer of the Sm2 Fe17N3 grains. However, the Sm-Fe-Cu-Al binder was contaminated by carbon and nitrogen, which originated from the organic solvent used as the milling medium during pulverization. To prevent carbon and nitrogen contamination, the Sm-Fe- Cu-Al alloy was added directly on the surface of the Sm2Fe17N3 grains by sputtering. Comparing the recovered coercivity per unit amount of the added binder the uncontaminated binder-coated sample had a higher coercivity recovery effect than the milled binder-added sample. These results suggested that sufficient addition of the contamination-free Sm-Fe-Cu-Al binder has the possibility to reduce the amount of binder necessary to produce a high coercive Sm2Fe17N3 magnet.

Simultaneous preconcentration of Cu, Fe and Pb as methylthymol blue complexes on naphthalene adsorbent and flame atomic absorption determination

International Nuclear Information System (INIS)

Pourreza, Nahid; Hoveizavi, Reza

2005-01-01

A simultaneous preconcentration method was developed for determination of trace amounts of Cu, Fe and Pb by atomic absorption spectrometry. The method is based on the retention of their methylthymol blue complexes by naphthalene methyltrioctyl ammonium chloride adsorbent in a column. The adsorbed metal complexes were eluted from the column with nitric acid and Cu, Fe and Pb were determined by flame atomic absorption spectrometry. Several parameters such as pH of the sample solution, ligand concentration, volume of the sample and the amount of methyltrioctyl ammonium chloride loaded on naphthalene were evaluated. The effect of diverse ions on the preconcentration was also investigated. A preconcentration factor of up to 100 or more can easily be achieved depending on the volume of the sample taken. The calibration graphs were obtained in the range of 5-40, 10-100 and 10-200 ng ml -1 for Cu, Fe and Pb in the initial solution, respectively, when using 500 ml of the solution. The detection limit based on three standard deviations of the blank was 0.54, 3.1, and 4.5 ng ml -1 for Cu, Fe and Pb, respectively. The relative standard deviations (R.S.D.) of 0.62-1.4% for Cu, 1.9-3.4% for Fe and 1.0-2.2% for Pb were obtained. The method was applied to the determination of Cu, Fe and Pb in river and wastewater samples

Photoelectron diffraction of magnetic ultrathin films: Fe/Cu(001)

Energy Technology Data Exchange (ETDEWEB)

Tobin, J.G. (Lawrence Livermore National Lab., CA (USA)); Wagner, M.K. (Wisconsin Univ., Madison, WI (USA). Dept. of Chemistry); Guo, X.Q.; Tong, S.Y. (Wisconsin Univ., Milwaukee, WI (USA). Dept. of Physics)

1991-01-03

The preliminary results of an ongoing investigation of Fe/Cu(001) are presented here. Energy dependent photoelectron diffraction, including the spin-dependent variant using the multiplet split Fe3s state, is being used to investigate the nanoscale structures formed by near-monolayer deposits of Fe onto Cu(001). Core-level photoemission from the Fe3p and Fe3s states has been generated using synchrotron radiation as the tunable excitation source. Tentatively, a comparison of the experimental Fe3p cross section measurements with multiple scattering calculations indicates that the Fe is in a fourfold hollow site with a spacing of 3.6{Angstrom} between it and the atom directly beneath it, in the third layer. This is consistent with an FCC structure. The possibility of utilizing spin-dependent photoelectron diffraction to investigate magnetic ultrathin films will be demonstrated, using our preliminary spectra of the multiplet-split Fe3s os near-monolayer Fe/Cu(001). 18 refs., 10 figs.

Facile preparation of magnetic mesoporous Fe{sub 3}O{sub 4}/C/Cu composites as high performance Fenton-like catalysts

Energy Technology Data Exchange (ETDEWEB)

Li, Keyan; Zhao, Yongqin [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Janik, Michael J. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Song, Chunshan [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); EMS Energy Institute, PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Guo, Xinwen, E-mail: guoxw@dlut.edu.cn [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)

2017-02-28

Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe{sub 3}O{sub 4}/C/Cu was obtained by calcining tartrate under N{sub 2}. • Fe{sub 3}O{sub 4}/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe{sub 2}O{sub 3}/CuO and α-Fe{sub 2}O{sub 3}/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe{sub 3}O{sub 4}/C/Cu was obtained by calcining the tartrate precursor under N{sub 2} atmosphere at 500 °C. The Fe{sub 3}O{sub 4}/C/Cu composite possessed mesoporous structure and large surface area up to 133 m{sup 2} g{sup −1}. The Fenton catalytic performance of Fe{sub 3}O{sub 4}/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe{sup 3+} to Fe{sup 2+}, which accelerated the Fe{sup 3+}/Fe{sup 2+} cycles and favored H{sub 2}O{sub 2} decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe{sup 3+} and Cu{sup 2+}, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe{sub 3}O{sub 4}/C/Cu-H{sub 2}O{sub 2} system, and MB (100 mg L{sup −1}) was nearly removed within 60 min. The Fe{sub 3}O{sub 4}/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile

Giant magnetoimpedance effect in sputtered single layered NiFe film and meander NiFe/Cu/NiFe film

International Nuclear Information System (INIS)

Chen, L.; Zhou, Y.; Lei, C.; Zhou, Z.M.; Ding, W.

2010-01-01

Giant magnetoimpedance (GMI) effect on NiFe thin film is very promising due to its application in developing the magnetic field sensors with highly sensitivity and low cost. In this paper, the single layered NiFe thin film and NiFe/Cu/NiFe thin film with a meander structure are prepared by the MEMS technology. The influences of sputtering parameters, film structure and conductor layer width on GMI effect in NiFe single layer and meander NiFe/Cu/NiFe film are investigated. Maximum of the GMI ratio in single layer and sandwich film is 5% and 64%, respectively. The results obtained are useful for developing the high-performance magnetic sensors based on NiFe thin film.

Effect of Ag micro-alloying on the microstructure and properties of Cu-14Fe in situ composite

International Nuclear Information System (INIS)

Liu, K.M.; Lu, D.P.; Zhou, H.T.; Atrens, A.; Zou, J.; Yang, Y.L.; Zeng, S.M.

2010-01-01

This paper studied Ag micro-alloying in the deformation-processed Cu-14Fe in situ composite, by a comparison of Cu-14Fe and Cu-14Fe-0.06Ag. Each alloy was prepared by casting and processed into an in situ composite by hot and cold working. The microstructures were documented using light microscopy and scanning electron microscopy (SEM). The mechanical properties were measured with a tensile-testing machine. The electrical conductivity was measured with a micro-ohmmeter. For both alloys, the as-cast microstructure consisted of a Cu matrix and Fe dendrites; after hot and cold working the microstructure consisted of a Cu matrix containing Fe fibres elongated in the working direction. The as-cast Ag-containing alloy contained finer Fe dendrites. The Ag-containing in situ composite had thinner Fe fibres, higher tensile strength, higher ductility, and higher conductivity. The cold worked Cu-14Fe-0.06Ag in situ composite with cumulative cold deformation strain η = 7.8 (where η = ln(A 0 /A) and A 0 and A are the original and final cross-section areas, respectively), achieved a tensile strength of 930 MPa and a conductivity of 56%IACS (International Annealed Copper Standard; 17.241 nΩ m is defined as 100%IACS). The Ag micro-alloyed in situ composite had a combination of properties comparable to that of a much more expensive alloy containing much more Ag. After 1 h heat treatment at 300 deg. C, the tensile strength was increased to 950 MPa and the conductivity was increased to 56.4%IACS.

Stress impedance effect of FeCoSiB/Cu/FeCoSiB sandwich layers on flexible substrate

International Nuclear Information System (INIS)

Peng, B.; Zhang, W.L.; Liu, J.D.; Zhang, W.X.

2011-01-01

FeCoSiB/Cu/FeCoSiB sandwich layers were deposited on flexible substrate to develop flexible stress/strain sensors. The influence of stress on the impedance of the multilayers is reported. The results show that the variation of the impedance increases with the increase in deflection of the free end of the cantilever. A relative change in impedance of 6.4% is obtained in the FeCoSiB(1.5 μm)/Cu(0.25 μm)/FeCoSiB(1.5 μm) sandwich layers at 1 MHz with deflection of 2 mm. The stress impedance effects are sensitive to the frequency of the current and the thickness of both FeCoSiB and Cu layers. The stress impedance effect increases with the increase in the thickness of FeCoSiB or Cu layers. The stress impedance effect increases slightly with the increase in frequency and decreases with the further increase in frequency, which can be understood by the stress and frequency-dependent permeability of magnetic films. - Research highlights: → We deposited FeCoSiB/Cu/FeCoSiB multilayer on flexible substrate. → We studied the stress impedance effect of FeCoSiB/Cu/FeCoSiB multilayer. → Stress impedance effect increases with thickness of both FeCoSiB and Cu layer.→ Stress impedance effect is dependent on current frequency. → Results are understood using stress and frequency-dependent permeability.

Tailoring Graphene Morphology and Orientation on Cu(100), Cu(110), and Cu(111)

Science.gov (United States)

Jacobberger, Robert; Arnold, Michael

2013-03-01

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

Phase Competition Induced Bio-Electrochemical Resistance and Bio-Compatibility Effect in Nanocrystalline Zr x -Cu100-x Thin Films.

Science.gov (United States)

Badhirappan, Geetha Priyadarshini; Nallasivam, Vignesh; Varadarajan, Madhuri; Leobeemrao, Vasantha Priya; Bose, Sivakumar; Venugopal, Elakkiya; Rajendran, Selvakumar; Angleo, Peter Chrysologue

2018-07-01

Nano-crystalline Zrx-Cu100-x (x = 20-100 at.%) thin films with thickness ranging from 50 to 185 nm were deposited by magnetron co-sputtering with individual Zr and Cu targets. The as-sputtered thin films were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Atomic Force Microscopy (AFM) and Glancing Incidence X-ray Diffraction (GIXRD) for structural and morphological properties. The crystallite size was found to decrease from 57 nm to 37 nm upon increasing the Zr content from 20 to 30 at.% with slight increase in the lattice strain from 0.17 to 0.33%. Further, increase in Zr content to 40 at.% leads to increase in the crystallite size to 57 nm due to stabilization of C10Zr7 phase along with the presence of nanocrystalline Cu-Zr phase. A bimodal distribution of grain size was observed from FE-SEM micrograph was attributed to the highest surface roughness in Zr30Cu70 thin films comprised of Cu10Zr7, Cu9Zr2, Cu-Zr intermetallic phases. In-vitro electrochemical behaviors of nano-crystalline Zrx-Cu100-x thin films in simulated body fluid (SBF) were investigated using potentiodynamic polarization studies. Electrochemical impedance spectroscopy (EIS) data fitting by equivalent electrical circuit fit model suggests that inner bulk layer contributes to high bio-corrosion resistance in Zrx-Cu100-x thin films with increase in Zr content. The results of cyto-compatibility assay suggested that Zr-Cu thin film did not introduce cytotoxicity to osteoblast cells, indicating its suitability as a bio-coating for minimally invasive medical devices.

Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

KAUST Repository

Hassnain Jaffari, G.; Aftab, M.; Anjum, Dalaver H.; Cha, Dong Kyu; Poirier, Gerald; Ismat Shah, S.

2015-01-01

Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a magnetic moment being equal to about 2.13 μB/Fe atom and a bulk like negligible value of coercivity over the temperature range of 5–300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in magnetic character. However, for the annealed sample phase separated Fe exhibited homogenous strain.

Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

KAUST Repository

Hassnain Jaffari, G.

2015-12-16

Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a magnetic moment being equal to about 2.13 μB/Fe atom and a bulk like negligible value of coercivity over the temperature range of 5–300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in magnetic character. However, for the annealed sample phase separated Fe exhibited homogenous strain.

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)

The application of photoelectron spectroscopy in the study of corrosion and oxidation mechanisms of alloys: Inconel 182, Fe/Cu(100 and U-Zr-Nb

International Nuclear Information System (INIS)

Mendonca, Renato de

2011-05-01

In. this work a study of the oxidation/corrosion process of three systems of metallic materials by Photoemission Spectroscopy is presented. In the first system, it was investigated the corrosion of Ineonel 182 at simulated Pressurized Water Reactor (PWR) environment. Samples with and without surface chemical treatment were exposed to the simulated environment for until 18 weeks. The oxide layer formed on the surfaces of the samples at different conditions was characterized by Scanning Electron Microscopy and XPS coupled with argon ion sputtering. The comparison between the oxide films grown on the samples showed that the oxide layer formed on the chemically treated sample is thinner and relatively Cr-rich. In second system it was studied the initial oxidation at room temperature of epitaxial films of Fe evapored on Cu (100). The films were deposited with two different thicknesses in order to get tbe fcc Fe (100) and bcc Fe (110) surfaces. The results, obtained by photoemission spectroscopy at the TEMPO beamline of the Synchrotron Soleil, showed the formation of distinct oxides films. The surfaces also presented different kinetics of oxidation and the (110) Fe-bcc showed highest reactivity. The analysis of the data indicated the Fe 1-x O formation on fcc Fe (100) and suggested the Fe 1-x O and FC 3 0 4 formation on (110) Fe-bcc surface. In the last system, it was investigated the initial oxidation of U-Zr-Nb alloys at room temperature. For this experiment, the alloys were exposed to oxygen in ultra high vacuum. The analysis of the U 4f peak showed the fast formation of U) 2 on the surfaces and similar kinetics of oxidation between the U and the U-Zr-Nb alloy. The alloying elements showed slower oxidation. The Zr 3d peak suggested the zr0 2 formation while the Nb 3d peak showed a remarkable enlargement that became necessary a deconvolution which indicated the formation ofNhO , Nb0 2 and N 2 0 5 . (author)

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.

Crystal and magnetic structures of CaCu3Fe4O12 and LaCu3Fe4O12: distinct charge transitions of unusual high valence Fe

International Nuclear Information System (INIS)

Shimakawa, Yuichi

2015-01-01

New 134-type perovskites, CaCu 3 Fe 4 O 12 (CCFO) and LaCu 3 Fe 4 O 12 (LCFO), were prepared by means of high-pressure synthesis. The compounds contain unusual high valence Fe 4+ in CCFO and Fe 3.75+ in LCFO at high temperatures. With decreasing temperature, the instabilities of the high valence states of Fe are relieved by distinct charge transitions, which are charge disproportionation (4Fe 4+   →  2Fe 3+   +  2Fe 5+ ) in CCFO and intermetallic charge transfer (3Cu 2+   +  4Fe 3.75+   →  3Cu 3+   +  4Fe 3+ ) in LCFO. Crystal structure analysis with synchrotron x-ray diffraction and magnetic structure analysis with neutron diffraction revealed the nature of the transitions. Although the two behaviors look completely different from each other in simple ionic models, they can both be explained by the localization of ligand holes, which are produced by the strong hybridization of low-lying Fe-d and oxygen p orbitals in the oxides. The ligand holes in the charge disproportionated CCFO are localized at the Fe–O sites alternately (4d 5 L  →  2d 5   +  2d 5 L 2 ) and the ligand holes in the charge transferred LCFO are localized at the Cu–O sites (3d 9   +  4d 5 L 0.75   →  3d 9 L  +  4d 5 ). (review)

A route for recycling Nd from Nd-Fe-B magnets using Cu melts

Energy Technology Data Exchange (ETDEWEB)

Moore, Martina; Gebert, Annett, E-mail: a.gebert@ifw-dresden.de; Stoica, Mihai; Uhlemann, Margitta; Löser, Wolfgang

2015-10-25

Phase evolutions in Nd-Fe-B magnet/Cu systems have been explored with regard to Nd recycling. It was demonstrated that large scale phase separation into a ferromagnetic Fe(B)-rich ingot core with α-Fe main phase and a non-magnetic (Cu,Nd)-rich ingot rim takes place upon arc melting with Cu fractions ≥ 21.5 wt.-%. The re-solidification of the Nd{sub 2}Fe{sub 14}B magnet main phase is suppressed. The rim consists of the Cu{sub 2}Nd main phase and CuNd/Cu{sub 4}Nd minority phases in which Al traces from the magnetic material are gathered. Induction melting of such Nd-Fe-B/Cu mixtures can support the separation of these phase regions with very sharp boundaries. Main features of liquid phase separation and microstructure evolution have been interpreted on the basis of Nd-Fe-Cu phase diagram data. The key advantage with respect to Nd recycling from Nd-Fe-B permanent magnet scrap is the substantial accumulation of Nd in the (Cu,Nd)-rich region of the phase separated solidified specimen, which can be easily detached from the Fe-rich part by mechanical-magnetic treatments. Such portions contained up to ∼44 wt.-% Nd (25 at.-%) in first lab-scale experiments. Nd recovery from the (Cu,Nd)-rich fractions is possible by exploiting the large chemical property differences between the reactive rare earths elements and Cu. - Highlights: • phase evolution analysis in Nd-Fe-B magnet/Cu systems with regard to Nd recycling. • Cu ≥ 21 wt.-%, large scale phase separation- Fe(B)-rich ingot core, (Cu,Nd)-rich rim. • high Nd content (∼44 wt.-%) of (Cu,Nd)-rich region, mechanical-magnetic treatments.

Ultrafast magnon generation in an Fe film on Cu(100).

Science.gov (United States)

Schmidt, A B; Pickel, M; Donath, M; Buczek, P; Ernst, A; Zhukov, V P; Echenique, P M; Sandratskii, L M; Chulkov, E V; Weinelt, M

2010-11-05

We report on a combined experimental and theoretical study of the spin-dependent relaxation processes in the electron system of an iron film on Cu(100). Spin-, time-, energy- and angle-resolved two-photon photoemission shows a strong characteristic dependence of the lifetime of photoexcited electrons on their spin and energy. Ab initio calculations as well as a many-body treatment corroborate that the observed properties are determined by relaxation processes involving magnon emission. Thereby we demonstrate that magnon emission by hot electrons occurs on the femtosecond time scale and thus provides a significant source of ultrafast spin-flip processes. Furthermore, engineering of the magnon spectrum paves the way for tuning the dynamic properties of magnetic materials.

Sorption Mechanisms of Cesium on Cu II2Fe II(CN) 6and Cu II3[Fe III(CN) 6] 2Hexacyanoferrates and Their Relation to the Crystalline Structure

Science.gov (United States)

Ayrault, S.; Jimenez, B.; Garnier, E.; Fedoroff, M.; Jones, D. J.; Loos-Neskovic, C.

1998-12-01

CuII2FeII(CN)6·xH2O and CuII3[FeIII(CN)6]2·xH2O can be prepared with reproducible chemical compositions and structures after careful washing. They have cubicFmoverline3mstructures with iron vacancies. In CuII2FeII(CN)6, copper occupies two different sites: Cu1 in position 4blinked to Fe through the CN groups, and Cu2 not linked to the CN groups and partially occupying the interstitial 24epositions. The second type of site is not present in CuII3[FeIII(CN)6]2. Sorption kinetics and isotherms were determined for cesium on both hexacyanoferrates by batch experiments. On CuII3[FeIII(CN)6]2, the maximum uptake is only 0.073 Cs/Fe (at./at.). On CuII2FeII(CN)6, the uptake reaches 1.5 Cs/Fe. The sorption kinetics include at least two steps: at1/2variation until approximately 72 h and then a slow evolution studied up to 6 months. The sorption mechanism is complex. The main process seems to be diffusion of ion pairs, followed by a reorganization of the solid, resulting in one or more new solid phases. The presence of the Cu2 site seems to play a favorable role in the sorption. Owing to its good midterm stability and the first rapid step of exchange, CuII2FeII(CN)6·xH2O seems to be one of the most promising compounds for the recovery of cesium from nuclear liquid wastes.

Magnetic properties of nanostructured CuFe2O4

DEFF Research Database (Denmark)

Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

1999-01-01

The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high...

Magnetic Excitations in Cu2Fe2Ge4O13

International Nuclear Information System (INIS)

Masuda, Takatsugu; Zheludev, Andrey I.; Sales, Brian C.; Imai, S.; Uchinokura, K.

2005-01-01

Magnetic excitations in the cooperative ordered state in a weakly coupled Fe chains and Cu dimers compound Cu 2 Fe 2 Ge 4 O 13 is studied by thermal neutron scattering technique. We show that the low energy excitations up to 10 meV in wide q range are well described by spin wave theory of weakly coupled Fe chains. In higher energy range a narrow band excitation that can be associated with Cu dimers is observed at ℎω-24 meV. Both types of excitations can be understood by treating the weak coupling between Fe chains and Cu dimers at the level of Mean Field/Random Phase Approximation.

Novel Chiral Magnetic Domain Wall Structure in Fe/Ni/Cu(001) Films

Science.gov (United States)

Chen, G.; Zhu, J.; Quesada, A.; Li, J.; N'Diaye, A. T.; Huo, Y.; Ma, T. P.; Chen, Y.; Kwon, H. Y.; Won, C.; Qiu, Z. Q.; Schmid, A. K.; Wu, Y. Z.

2013-04-01

Using spin-polarized low energy electron microscopy, we discovered a new type of domain wall structure in perpendicularly magnetized Fe/Ni bilayers grown epitaxially on Cu(100). Specifically, we observed unexpected Néel-type walls with fixed chirality in the magnetic stripe phase. Furthermore, we find that the chirality of the domain walls is determined by the film growth order with the chirality being right handed in Fe/Ni bilayers and left handed in Ni/Fe bilayers, suggesting that the underlying mechanism is the Dzyaloshinskii-Moriya interaction at the film interfaces. Our observations may open a new route to control chiral spin structures using interfacial engineering in transition metal heterostructures.

Room temperature ferromagnetism in Fe-doped CuO nanoparticles.

Science.gov (United States)

Layek, Samar; Verma, H C

2013-03-01

The pure and Fe-doped CuO nanoparticles of the series Cu(1-x)Fe(x)O (x = 0.00, 0.02, 0.04, 0.06 and 0.08) were successfully prepared by a simple low temperature sol-gel method using metal nitrates and citric acid. Rietveld refinement of the X-ray diffraction data showed that all the samples were single phase crystallized in monoclinic structure of space group C2/c with average crystallite size of about 25 nm and unit cell volume decreases with increasing iron doping concentration. TEM micrograph showed nearly spherical shaped agglomerated particles of 4% Fe-doped CuO with average diameter 26 nm. Pure CuO showed weak ferromagnetic behavior at room temperature with coercive field of 67 Oe. The ferromagnetic properties were greatly enhanced with Fe-doping in the CuO matrix. All the doped samples showed ferromagnetism at room temperature with a noticeable coercive field. Saturation magnetization increases with increasing Fe-doping, becomes highest for 4% doping then decreases for further doping which confirms that the ferromagnetism in these nanoparticles are intrinsic and are not resulting from any impurity phases. The ZFC and FC branches of the temperature dependent magnetization (measured in the range of 10-350 K by SQUID magnetometer) look like typical ferromagnetic nanoparticles and indicates that the ferromagnetic Curie temperature is above 350 K.

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)

High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

Science.gov (United States)

Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

1991-08-27

A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

Science.gov (United States)

Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

1991-08-27

A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

Ground state magnetic properties of Fe nanoislands on Cu(111)

International Nuclear Information System (INIS)

Kishi, Tomoya; David, Melanie; Nakanishi, Hiroshi; Kasai, Hideaki; Dino, Wilson Agerico; Komori, Fumio

2005-01-01

We investigate magnetic properties of Fe nanoislands on Cu(111) in the relaxed structure within the density functional theory. We observe that the nanoislands exhibit the ferromagnetic properties with large magnetic moment. We find that the change in the magnetic moment of each Fe atom is induced by deposition on Cu(111) and structure relaxation of Fe nanoislands. Moreover, we examine the stability of ferromagnetic states of Fe nanoislands by performing the total energy calculations. (author)

A Novel Ternary CoFe2O4/CuO/CoFe2O4 as a Giant Magnetoresistance Sensor

Directory of Open Access Journals (Sweden)

Ramli

2016-12-01

Full Text Available This paper reports the results of a study relating to the synthesis of a novel ternary CoFe2O4/CuO/CoFe2O4 thin film as a giant magnetoresistance (GMR sensor. The CoFe2O4/CuO/CoFe2O4 thin film was prepared onto silicon substrate via DC magnetron sputtering with the targets facing each other. X-ray diffraction was used to determine the structure of the thin film and a 4-point method was used to measure the MR ratio. The GMR ratio is highly dependent on the ferrimagnetic (CoFe2O4 and nonmagnetic (CuO layer thickness. The maximum GMR ratio at room temperature obtained in the CoFe2O4/CuO/CoFe2O4 thin film was 70% when the CoFe2O4 and the CuO layer had a thickness of 62.5 nm and 14.4 nm respectively.

Effect of MnCuFe{sub 2}O{sub 4} content on magnetic and dielectric properties of poly (O-Phenylenediamine)/MnCuFe{sub 2}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

2016-03-01

Poly o-phenylenediamine (PoPD)/MnCuFe{sub 2}O{sub 4} nanocomposites with three different ratios of MnCuFe{sub 2}O{sub 4} (10%, 20%, 30% w/w) were synthesized by in-situ oxidative chemical polymerization method ammonium persulphate used as oxidant, while MnCuFe{sub 2}O{sub 4} nanoparticles was prepared by auto-combustion method. The structure, morphology and magnetic properties of synthesized PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites were characterized by FT-IR, UV–visible absorption spectra, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Vibrating sample magnetometer (VSM). FTIR spectra and XRD were confirmed the formation of the PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites. The morphology of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites is visualized through SEM and TEM. The spherical morphology of the PoPD was confirmed using SEM analysis. Dielectric properties of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites at different temperatures have been performed in the frequency range of 50 Hz–5 MHz. The optical absorption experiments of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites reveal that the direct transition with an energy band gap is around 2 eV. - Highlights: • Green synthesis of PoPD (the polymerization carried out only in aqueous medium) by in-situ chemical polymerization method. • For the first time, PoPD incorporated with MnCuFe{sub 2}O{sub 4} with lesser particle size. • The auto combustion reaction, support to achieve less particle size. • Ferrite content affects the magnetic properties of the nanocomposites.

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

CoFe Layers Thickness and Annealing Effect on the Magnetic Behavior of the CoFe/Cu Multilayer Nanowires

Directory of Open Access Journals (Sweden)

M. Ahmadzadeh

2015-04-01

Full Text Available CoFe/Cu multilayer nanowires were electrodeposited into anodic aluminum oxide templates prepared by a two-step mild anodization method, using the single-bath technique. Nanowires with 30 nm diameter and the definite lengths were obtained. The effect of CoFe layers thickness and annealing on the magnetic behavior of the multilayer nanowires was investigated. The layers thickness was controlled through the pulses numbers: 200, 260, 310,360 and 410 pulses were used to deposit the CoFe layers, while 300 pulse for the Cu layers. A certain increase in coercivity and squareness of CoFe/Cu multilayer nanowires observed with increasing the CoFe layer thickness and annealing improved the coercivity and decrease squareness of CoFe/Cu multilayer nanowires. First order reversal curves after annealed showed amount domains with soft magnetic phase, it also shows decreasing spreading of distribution function along the Hu axis after annealed

Short-range ferromagnetism in alloy ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

Energy Technology Data Exchange (ETDEWEB)

THANH, P. Q.; HOA, N. Q.; CHAU, N. [Vietnam National University, Hanoi (Viet Nam); HUU, C. X. [Danang University of Technology, Danang (Viet Nam); NGO, D. T. [Technical University of Denmark, Kgs. Lyngby (Denmark); PHAN, T. L. [Chungbuk National University, Cheongju (Korea, Republic of)

2014-04-15

We have studied the magnetic properties of two amorphous alloy ribbons Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Ag{sub 1} (FCSNB-Ag) and Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Cu{sub 1} (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (T{sub C} ) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded the exponent values of β = 0.369 ± 0.005, γ = 1.359 ± 0.005 and δ = 4.7 ± 0.1 for FCSNB-Ag, and β = 0.376 ± 0.002, γ = 1.315 ± 0.006 and δ = 4.5 ± 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D Heisenberg model, demonstrating the existence of short-range FM order in the amorphous alloy ribbons.

Interplay between interface structure and magnetism in NiFe/Cu/Ni-based pseudo-spin valves

Science.gov (United States)

Loving, Melissa G.; Ambrose, Thomas F.; Ermer, Henry; Miller, Don; Naaman, Ofer

2018-05-01

Magnetic pseudo spin valves (PSVs) with superconducting Nb electrodes, have been leading candidates for an energy-efficient memory solution compatible with cryogenic operation of ultra-low power superconducting logic. Integration of these PSV Josephson junctions in a standard multi-layer Nb process requires growing high-quality thin magnetic films on a thick Nb bottom electrode (i.e. ≥1.5kÅ, to achieve bulk superconducting properties). However, as deposited, 1.5kÅ Nb exhibits a rough surface with a characteristic rice grain morphology, which severely degrades the switching properties of subsequently deposited PSVs. Therefore, in order to achieve coherent switching throughout a PSV, the Nb interface must be modified. Here, we demonstrate that the Nb surface morphology and PSV crystallinity can be altered with the incorporation of separate 50Å Cu or 100Å Al/50Å Cu non-magnetic seed layers, and demonstrate their impact on the magnetic switching of a 15Å Ni80Fe20/50Å Cu/20Å Ni PSV, at both room temperature and at 10 K. Most notably, these results show that the incorporation of an Al seed layer leads to an improved face centered cubic templating through the bulk of the PSV, and ultimately to superior magnetic switching.

Sb interactions with TaC precipitates and Cu in ion-implanted α-Fe

International Nuclear Information System (INIS)

Follstaedt, D.M.; Myers, S.M.

1980-01-01

The interactions of Sb with the other species implanted into Fe to form Fe-Ta-C-Sb and Fe-Cu-Sb alloys have been examined with transmission electron microscopy and Rutherford backscattering following annealing at 873 0 K. Trapping of Sb at TaC precipitates is observed in the former alloy just as was previously observed in Fe-Ti-C-Sb. In Fe-Cu-Sb, Sb interactions are governed by the atomic ratio of Sb to Cu. For ratios between 0.2 to 0.4, the compound β-Cu 3 Sb was observed to form. For Sb to Cu ratios approx.< 0.1, fcc Cu precipitates were observed. In addition to the expected Sb dissolution in Cu, Sb trapping by Cu precipitates is also observed. The binding enthalpy of Sb at both TaC and Cu precipitates with respect to a solution site in the bcc Fe is the same as observed for TiC, approx. 0.4 eV. The constancy of the binding enthalpy at such chemically dissimilar precipitates supports the hypothesis that the trapping is due to the structural discontinuity of the precipitate-host interface. The observed Sb trapping at precipitates is of potential significance for the control of temper embrittlement in bcc steels

Co{sub 100−x}Fe{sub x} magnetic thick films prepared by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Aguirre, M. del C., E-mail: carmenaguirre@famaf.unc.edu.ar [Instituto de Física Enrique Gaviola-Conicet-Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); Farías, E. [Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); Abraham, J.; Urreta, S.E. [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina)

2015-04-05

Highlights: • Low iron containing films are compact, with rounded, relatively uniform surfaces. • Larger Fe contents exhibit nanowall networks covering the surface. • Coercivity in the out of plane configuration is larger than in the easy axis direction. • Co-rich films nucleate and grow by a 3DP diffusion controlled mechanism. • For equiatomic Fe{sub 50}Co{sub 50} films, nucleation tends to become instantaneous. - Abstract: Co–Fe films are grown onto plane pre-treated Cu foils; the effects of the alloy composition on the morphology and the crystal texture of the electrodeposited films and their anisotropic magnetic hysteresis properties are explored. Nucleation and crystallization mechanisms in these Co-rich layers are also investigated with pulse-reverse plating techniques, using the first cathodic pulse current–time transients. In the diffusion controlled regime the deposition mechanism is found to involve progressive nucleation with three-dimensional (3D) growth, except for the equiatomic Fe{sub 50}Co{sub 50} solution where nucleation tends to become instantaneous. The different morphologies and size scales observed are described and correlated with coercivity. The films are electrodeposited onto electrochemically pre-treated Cu substrates from feeds of nominal Fe/Co mol ratios between 0/100 and 50/50. The composition of the deposited layers, as determined by energy dispersive X-ray spectroscopy, are quite close to the nominal values. Cyclic voltammetry determinations exhibit only a single reduction process on the cathode, indicating that a unique (Co{sub 100−x}Fe{sub x}) phase grows. Depending on composition and on the substrate pre-treatment, these layers exhibit textures with features of different sizes. X ray diffraction patterns indicate that the nanostructures with Fe contents above 20 at.% crystallize in a body-centered cubic cell, while samples with Fe contents below this value are fcc. Regarding the effect of composition on the

Formation of SmFe5(0001) ordered alloy thin films on Cu(111) single-crystal underlayers

International Nuclear Information System (INIS)

Yabuhara, Osamu; Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

2010-01-01

SmFe 5 (0001) single-crystal thin films are prepared by molecular beam epitaxy employing Cu(111) single-crystal underlayers on MgO(111) substrates. The Cu atoms diffuse into the Sm-Fe layer and substitute the Fe sites in SmFe 5 structure forming an alloy compound of Sm(Fe,Cu) 5 . The Sm(Fe,Cu) 5 film is more Cu enriched with increasing the substrate temperature. The Cu underlayer plays an important role in assisting the formation of the ordered phase.

Synthesis and magnetic properties of multilayer Ni/Cu and NiFe/Cu ...

Indian Academy of Sciences (India)

The diameter of wires can be easily varied by pore size of alumina, ranging ... saturated HgCl2 solution to remove the remaining Al, and then dipped in 5 wt% ... for NiFe alloy it is 1.3 V, that is higher than for Ni/Cu nanowires to diminish Cu.

High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

International Nuclear Information System (INIS)

Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam; Singh, Chandan K.; Kabir, Mukul; Thakur, Gohil S.; Haque, Zeba; Gupta, L. C.; Ganguli, Ashok K.

2016-01-01

CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

Energy Technology Data Exchange (ETDEWEB)

Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO 140306 (India); Singh, Chandan K.; Kabir, Mukul [Department of Physics, Indian Institute of Science Education and Research, Pune 411008 (India); Thakur, Gohil S.; Haque, Zeba; Gupta, L. C. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Institute of Nano Science & Technology, Mohali 160064 (India)

2016-06-13

CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

Room temperature deposition of amorphous p-type CuFeO2 and ...

Indian Academy of Sciences (India)

fabrication of CuFeO2/n-Si heterojunction by RF sputtering method. TAO ZHU1 ... Transparent conducting amorphous p-type CuFeO2 (CFO) thin film was prepared by radio-frequency ... Delafossite oxides CuMO2 (M is trivalent cation, such as.

Structural properties of iron nitride on Cu(100): An ab-initio molecular dynamics study

KAUST Repository

Heryadi, Dodi

2011-01-01

Due to their potential applications in magnetic storage devices, iron nitrides have been a subject of numerous experimental and theoretical investigations. Thin films of iron nitride have been successfully grown on different substrates. To study the structural properties of a single monolayer film of FeN we have performed an ab-initio molecular dynamics simulation of its formation on a Cu(100) substrate. The iron nitride layer formed in our simulation shows a p4gm(2x2) reconstructed surface, in agreement with experimental results. In addition to its structural properties, we are also able to determine the magnetization of this thin film. Our results show that one monolayer of iron nitride on Cu(100) is ferromagnetic with a magnetic moment of 1.67 μ B. © 2011 Materials Research Society.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Energy Technology Data Exchange (ETDEWEB)

Huang, Shih-Yi [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min{sup −1} methane (CH{sub 4}) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g{sup −1} for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g{sup −1} (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

International Nuclear Information System (INIS)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A.C.

2014-01-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min −1 methane (CH 4 ) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g −1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g −1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour

Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zhengru, E-mail: zhengruzhu@gmail.com [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China); State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Xinyong; Zhao, Qidong [State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Yonghua; Sun, Caizhi; Cao, Yongqiang [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China)

2013-08-01

Graphical abstract: - Highlights: • CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. • Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. • The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. • Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.

Oxidative degradation of the antibiotic oxytetracycline by Cu@Fe3O4 core-shell nanoparticles.

Science.gov (United States)

Pham, Van Luan; Kim, Do-Gun; Ko, Seok-Oh

2018-08-01

A core-shell nanostructure composed of zero-valent Cu (core) and Fe 3 O 4 (shell) (Cu@Fe 3 O 4 ) was prepared by a simple reduction method and was evaluated for the degradation of oxytetracycline (OTC), an antibiotic. The Cu core and the Fe 3 O 4 shell were verified by X-ray diffractometry (XRD) and transmission electron microscopy. The optimal molar ratio of [Cu]/[Fe] (1/1) in Cu@Fe 3 O 4 created an outstanding synergic effect, leading to >99% OTC degradation as well as H 2 O 2 decomposition within 10min at the reaction conditions of 1g/L Cu@Fe 3 O 4 , 20mg/L OTC, 20mM H 2 O 2 , and pH3.0 (and even at pH9.0). The OTC degradation rate by Cu@Fe 3 O 4 was higher than obtained using single nanoparticle of Cu or Fe 3 O 4 . The results of the study using radical scavengers showed that OH is the major reactive oxygen species contributing to the OTC degradation. Finally, good stability, reusability, and magnetic separation were obtained with approximately 97% OTC degradation and no notable change in XRD patterns after the Cu@Fe 3 O 4 catalyst was reused five times. These results demonstrate that Cu@Fe 3 O 4 is a novel prospective candidate for the pharmaceutical and personal care products degradation in the aqueous phase. Copyright © 2018 Elsevier B.V. All rights reserved.

Neutron diffraction study of Fe-substituted YBa2Cu3O7

International Nuclear Information System (INIS)

Balagurov, A.M.; Mironova, G.M.; Pajaczkowska, A.; Piechota, J.; Shimchak, Kh.

1989-01-01

Neutron diffraction spectra of YBa 2 (Cu 1-x Fe x )O 7-δ (0 2 planes were determined. It is significant that the doped iron atoms occupy both of the copper site. The substitution of Fe for Cu in (2q) site is proportional to the concentration of iron in the sample. For small x there are a considerable amount of vacancies (10%) in the Cu1 site, which disappear quickly if x increases. Therefore, a joint effect of Cu substitution and the filling in vacancies by Fe occures for the Cu1 site. The amount of oxygen in samples increases with x up to 7.06 for x=0.12. Any visible effect of location of Fe at the Ba site is absent, but we can not exclude it completely. 20 refs.; 4 figs.; 1 tab

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...

Fe and Cu stable isotopes in archeological human bones and their relationship to sex.

Science.gov (United States)

Jaouen, Klervia; Balter, Vincent; Herrscher, Estelle; Lamboux, Aline; Telouk, Philippe; Albarède, Francis

2012-07-01

Accurate sex assignment of ancient human remains usually relies on the availability of coxal bones or well-preserved DNA. Iron (Fe) and copper (Cu) stable isotope compositions ((56)Fe/(54)Fe and (65)Cu/(63)Cu, respectively) were recently measured in modern human blood, and an unexpected result was the discovery of a (56)Fe-depletion and a (65)Cu-enrichment in men's blood compared to women's blood. Bones, being pervasively irrigated by blood, are expected to retain the (56)Fe/(54)Fe and (65)Cu/(63)Cu signature of blood, which in turn is useful for determining the sex of ancient bones. Here, we report the (56)Fe/(54)Fe, (65)Cu/(63)Cu, and (66)Zn/(64)Zn ratios from a suite of well-preserved phalanxes (n = 43) belonging to individuals buried in the 17th and 18th centuries at the necropolis of Saint-Laurent de Grenoble, France, and for which the sex was independently estimated from pelvic bone morphology. The metals were purified from the bone matrix by liquid chromatography on ion exchange resin and the isotope compositions were measured by multiple-collector inductively coupled plasma mass spectrometry. The results show that, as expected from literature data on blood, male bone iron is depleted in (56)Fe and enriched in (65)Cu relative to female. No sex difference is found in the (66)Zn/(64)Zn ratios of bone. The concentration and isotopic data show no evidence of soil contamination. Four samples of five (77%) can be assigned their correct sex, a result comparable to sex assignment using Fe and Cu isotopes in blood (81%). Isotopic analysis of metals may therefore represent a valid method of sex assignment applicable to incomplete human remains. Copyright © 2012 Wiley Periodicals, Inc.

Characterization of transparent superconductivity Fe-doped CuCrO{sub 2} delafossite oxide

Energy Technology Data Exchange (ETDEWEB)

Taddee, Chutirat [Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Kamwanna, Teerasak, E-mail: teekam@kku.ac.th [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand); Amornkitbamrung, Vittaya [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand)

2016-09-01

Graphical abstract: - Highlights: • Effect of Fe substitution on the physical properties in CuCrO{sub 2} is studied. • The substitution of Cr{sup 3+} by Fe{sup 3+} produces a mixed effect on the magnetic properties. • CuCr{sub 1−x}Fe{sub x}O{sub 2} delafossite oxides show transparent superconductivity. - Abstract: Delafossite CuCr{sub 1−x}Fe{sub x}O{sub 2} (0.0 ≤ x ≤ 0.15) semiconductors were synthesized using a self-combustion urea nitrate process. The effects of Fe concentration on its microstructural, optical, magnetic, and electrical properties were investigated. X-ray diffraction (XRD) analysis results revealed the delafossite structure in all the samples. The lattice spacing of CuCr{sub 1−x}Fe{sub x}O{sub 2} slightly increased with increasing substitution of Fe at the Cr sites. The optical properties measured at room temperature using UV–visible spectroscopy showed a weak absorbability in the visible light and near IR regions. The corresponding direct optical band gap was about 3.61 eV, exhibiting transparency in the visible region. The magnetic hysteresis loop measurements showed that the Fe-doped CuCrO{sub 2} samples exhibited ferromagnetic behavior at room temperature. This indicated that the substitution of Fe{sup 3+} for Cr{sup 3+} produced a mixed effect on the magnetic properties of CuCrO{sub 2} delafossite oxide. The temperature dependent resistivity measurements clearly revealed the presence of superconductivity in the CuCr{sub 1−x}Fe{sub x}O{sub 2} with a superconducting transition up to 118 K.

Atomic-partial vibrational density of states of i-AlCuFe quasicrystals

International Nuclear Information System (INIS)

Parshin, P.P.; Zemlyanov, M.; Brand, R.A.; Dianoux, A.J.; Calvayrac, Y.

2002-01-01

We present new results on the separation of the atomic-partial vibrational density of states for the ternary quasicrystal i-Al 62 Cu 25.5 Fe 12.5 . The decomposition into three atomic-partial functions, Al-, Cu- and Fe-g(E), has been performed self-consistently with the calculation of the multi-phonon contributions. The results show the surprising result that both Cu- and Fe-g(E) are strongly peaked. The low-energy regions of Al- and Cu-g(E) show strong deviations from Debye behaviour due to the presence of non-propagating low-energy vibrational states. (orig.)

In-situ investigation of the icosahedral Al-Cu-Fe phase formation in thin films

Energy Technology Data Exchange (ETDEWEB)

Haidara, F., E-mail: fanta.haidara@im2np.fr [IM2NP, UMR 6242 CNRS - Universite Aix-Marseille, Av. Escadrille Normandie-Niemen, Case 142, 13397 Marseille Cedex 20 (France); Duployer, B. [Universite Paul Sabatier CIRIMAT-LCMIE 2R1, 118, Route de Narbonne, 31062 Toulouse Cedex 09 (France); Mangelinck, D.; Record, M.-C. [IM2NP, UMR 6242 CNRS - Universite Aix-Marseille, Av. Escadrille Normandie-Niemen, Case 142, 13397 Marseille Cedex 20 (France)

2012-09-05

Highlights: Black-Right-Pointing-Pointer We investigated the phase formation of i-Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} in thin films. Black-Right-Pointing-Pointer We characterized the samples by DSC and in-situ XRD and resistance measurements. Black-Right-Pointing-Pointer The resistivity value for i-Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} was determined. - Abstract: This work is an investigation of the formation by reactive diffusion at high temperatures of the icosahedral phase, i-Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}, in thin films. The samples were prepared by sputtering at room temperature. The elements Al, Cu and Fe were sequentially deposited onto oxidized silicon substrates. The two following stacking sequences, Al/Cu/Fe and Al/Fe/Cu, were investigated. The phase formation was studied using in situ resistivity, in situ X-ray Diffraction and Differential Scanning Calorimetry measurements. Whatever the stacking sequence, the sequences of phase formation evidenced during the heating treatment are similar. However the temperatures of formation for the first phases that are formed are different; they are higher in the case of the Al/Fe/Cu stacking sequence.

A study of a stable Al-Cu-Fe quasicrystal in solid and liquid state

International Nuclear Information System (INIS)

Chen Lifan; Chen Xishen

1992-01-01

A stable Al 65 Cu 20 Fe 15 quasicrystal with an icosahedral structure is studied in solid and liquid state. It is found that the icosahedral phase in Al 65 Cu 20 Fe 15 alloy does not grow directly from the pure liquid state, but rather forms between monoclinic Al 13 Fe 4 and residual liquid state at 865degC. The melting point of the Al 65 Cu 20 Fe 15 icosahedral quasicrystal occurs at 865degC and that of the Al 65 Cu 20 Fe 15 alloy occurs at 1008degC. Moreover, the monoclinic Al 13 Fe 4 is transformed into the icosahedral phase easily at the temperature of 845degC. The icosahedral quasicrystal in Al 65 Cu 20 Fe 15 alloy has a high thermal stability even at 950degC. Above 950degC, the icosahedral structure tends to an amorphous structure. (orig.)

Mechanism insight of pollutant degradation and bromate inhibition by Fe-Cu-MCM-41 catalyzed ozonation.

Science.gov (United States)

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

2018-03-15

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

Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO_2 mediated heterogeneous activation of peroxymonosulfate

International Nuclear Information System (INIS)

Ding, Yaobin; Tang, Hebin; Zhang, Shenghua; Wang, Songbo; Tang, Heqing

2016-01-01

Highlights: • CuFeO_2 microparticles were prepared by a microwave-assisted hydrothermal method. • CuFeO_2 microparticles efficiently catalyzed the activation of peroxymonosulfate. • Quenching experiments confirmed sulfate radicals as the major reactive radicals. • Carbamazepine was rapidly degraded by micro-CuFeO_2/peroxymonosulfate. • Feasibility of CuFeO_2/peroxymonosulfate was tested for treatment of actual water. - Abstract: Microscaled CuFeO_2 particles (micro-CuFeO_2) were rapidly prepared via a microwave-assisted hydrothermal method and characterized by scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. It was found that the micro-CuFeO_2 was of pure phase and a rhombohedral structure with size in the range of 2.8 ± 0.6 μm. The micro-CuFeO_2 efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO_4·−), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO_2 was observed to be 6.9 and 25.3 times that of micro-Cu_2O and micro-Fe_2O_3, respectively. The enhanced activity of micro-CuFeO_2 for the activation of PMS was confirmed to be attributed to synergistic effect of surface bonded Cu(I) and Fe(III). Sulfate radical was the primary radical species responsible for the CBZ degradation. As a microscaled catalyst, micro-CuFeO_2 can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu_2O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO_2 was effective in the studied actual aqueous environmental systems.

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)

Structural, dielectric and magnetic properties of SnO{sub 2}-CuFe{sub 2}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ali, Kashif [Department of Physics, International Islamic University, Islamabad (Pakistan); Iqbal, Javed, E-mail: javed.saggu@qau.edu.pk [Laboratory of Nanoscience and Technology (LNT), Department of Physics, Qaid-i-Azam University, Islamabad (Pakistan); Jan, Tariq [Department of Physics, University of Lahore, Sargodha Campus, Sargodha (Pakistan); Wan, Dongyun [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Ahmad, Naeem [Department of Physics, International Islamic University, Islamabad (Pakistan); Ahamd, Ishaq [Experimental Physics Labs, National Center for Physics, Islamabad (Pakistan); Ilyas, Syed Zafar [Department of Physics, Allama Iqbal Open University, Islamabad (Pakistan)

2017-04-15

The nanocomposites of (SnO{sub 2}){sub x}(CuFe{sub 2}O{sub 4}){sub (1−x)} (where x=0–100 wt%) have been successfully synthesized via two steps chemical method. XRD pattern has revealed the formation of inverse spinal phases with tetragonal crystal structure without any impurity phases for CuFe{sub 2}O{sub 4} sample. The thermodynamic solubility limit of SnO{sub 2} in CuFe{sub 2}O{sub 4} matrix has been found to be 30 wt% and above this percentage crystal phases related to SnO{sub 2} started to appear. The average particle size and shape of CuFe{sub 2}O{sub 4} nanoparticles have been strongly influenced by addition of SnO{sub 2} as depicted by TEM results. FTIR results have confirmed the existence of cation vibration bands at tetrahedral and octahedral sites along with Sn-O vibration band at higher concentrations, which also validates the formation of nanocomposites. Furthermore, the dielectric constant, tangent loss and conductivity of CuFe{sub 2}O{sub 4} nanoparticles have been found to increase up to 30 wt% addition of SnO{sub 2} and then decreases with further increase which is attributed to variations in resistivity and space charge carriers. Magnetic measurements have shown that saturation magnetization decreases from 35.68 emu/gm to 10.26 emu/gm with the addition of SnO{sub 2} content. - Highlights: • SnO{sub 2}-CuFe{sub 2}O{sub 4} nanocomposites with varying SnO{sub 2} concentrations were synthesized. • The thermodynamic solubility limit for SnO{sub 2} into CuFe{sub 2}O{sub 4} matrix by employing current method was found to be ≤30 wt%. • At higher concentrations, structural phases related to SnO{sub 2} started to appear. • FTIR results corroborated well with the XRD results. • It has been observed that the addition of SnO{sub 2} significantly influence the morphology, dielectric and magnetic properties of CuFe{sub 2}O{sub 4} nanoparticles.

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....

MIL-100-Fe derived N-doped Fe/Fe3C@C electrocatalysts for efficient oxygen reduction reaction

Science.gov (United States)

Guo, Dakai; Han, Sancan; Wang, Jiacheng; Zhu, Yufang

2018-03-01

N-doped porous Fe/Fe3C@C electrocatalysts were prepared by the pyrolysis of the hexamethylenetetramine (HMT)-incorporated MIL-100-Fe at different temperatures (700-1000 °C) under N2 atmosphere. Rotary evaporation of MIL-100-Fe and HMT solution could make more N-enriched HMT molecules enter into the pores of MIL-100-Fe, thus improving nitrogen contents of the final pyrolyzed samples. All pyrolyzed samples show porous textures with middle specific surface areas. The X-ray photoelectron spectroscopy (XPS) results demonstrate the successful introduction of N atoms into carbon framework. Sample Fe-N2-800 prepared by annealing the precursors with the HMT/MIL-100-Fe weight ratio of 2 at 800 °C exhibits the best electrocatalytic activity towards the oxygen reduction reaction (ORR) in terms of onset potential and current density because of high graphitic N and pyridinic N content. The enwrapped Fe/Fe3C nanoparticles and Fe-Nx active sites in these samples could also boost the ORR activity synergistically. Moreover, sample Fe-N2-800 demonstrates a dominant four electron reduction process, as well as excellent long-term operation stability and methanol crossover resistance. Thus, the N-doped Fe/Fe3C@C composites derived from the HMT-incorporated MIL-100-Fe are promising electrocatalysts to replace Pt/C for ORR in practical applications.

Formation of SmFe{sub 5}(0001) ordered alloy thin films on Cu(111) single-crystal underlayers

Energy Technology Data Exchange (ETDEWEB)

Yabuhara, Osamu; Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki [Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Kirino, Fumiyoshi, E-mail: yabuhara@futamoto.elect.chuo-u.ac.j [Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music, 12-8 Ueno-koen, Taito-ku, Tokyo 110-8714 (Japan)

2010-01-01

SmFe{sub 5}(0001) single-crystal thin films are prepared by molecular beam epitaxy employing Cu(111) single-crystal underlayers on MgO(111) substrates. The Cu atoms diffuse into the Sm-Fe layer and substitute the Fe sites in SmFe{sub 5} structure forming an alloy compound of Sm(Fe,Cu){sub 5}. The Sm(Fe,Cu){sub 5} film is more Cu enriched with increasing the substrate temperature. The Cu underlayer plays an important role in assisting the formation of the ordered phase.

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

Microstructural and magnetic characterizations of CoFeCu electrodeposited in self-assembled mesoporous silicon

Energy Technology Data Exchange (ETDEWEB)

Fortas, G., E-mail: g.fortas@gmail.com [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria); Université des Sciences et de la Technologie Houari Boumediene, Faculté des Physique, BP 32 El Alia 16111 Bab Ezzouar, Alger (Algeria); Haine, N. [Université des Sciences et de la Technologie Houari Boumediene, Faculté des Physique, BP 32 El Alia 16111 Bab Ezzouar, Alger (Algeria); Sam, S.; Gabouze, N. [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria); Saifi, A. [Université Mouloud Mammeri, laboratoire de physique et de chimie quantique, BP No. 17 RP Hasnaoua Tizi-Ouzou 15000 (Algeria); Ouir, S. [Université Said SDB, Route De Soumaa BP 270, Blida (Algeria); Menari, H. [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria)

2015-03-15

Self-assembled mesoporous silicon with quasi-regular pore arrangements has been fabricated by the electrochemical anodization process in hydrofluoric acid solution. CoFeCu was electrodeposited in this structure from a bath containing sodium acetate as a complexing agent with a pH value of 5. The effect of current density on the morphology, the structure and the magnetic properties of CoFeCu deposit was studied by SEM, EDS, DRX and VSM. It has been shown that the morphology and structure of samples were strongly influenced by the current density and etching duration. The micrographs show the vertical and branched nanowires and also a discontinuous growth of wires. Further, the growth of a thick layer from the grain boundaries of released CoFeCu wires is produced. The magnetic hysteresis loops demonstrate that the CoFeCu nanowires exhibit easy magnetic axis perpendicular to the PS channels axis when the current density varied from 3 to 10 mA/cm{sup 2}. Nevertheless, they reveal a no magnetic anisotropy of CoFeCu nanostructures deposited only in the outside of porous silicon, probably due to the vanishing the shape anisotropy. - Highlights: • CoFeCu deposit has been electrodeposited on self assembled mesoporous silicon. • SEM observation shows that CoFeCu embedded in Porous silicon channels. • Magnetic measurements show the anisotropy magnetic behavior of CoFeCu nanostructures. • The growth rate of nanowires is enhanced with an increase of current density.

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.

Atomic-partial vibrational density of states of i-AlCuFe quasicrystals

CERN Document Server

Parshin, P P; Brand, R A; Dianoux, A J; Calvayrac, Y

2002-01-01

We present new results on the separation of the atomic-partial vibrational density of states for the ternary quasicrystal i-Al sub 6 sub 2 Cu sub 2 sub 5 sub . sub 5 Fe sub 1 sub 2 sub . sub 5. The decomposition into three atomic-partial functions, Al-, Cu- and Fe-g(E), has been performed self-consistently with the calculation of the multi-phonon contributions. The results show the surprising result that both Cu- and Fe-g(E) are strongly peaked. The low-energy regions of Al- and Cu-g(E) show strong deviations from Debye behaviour due to the presence of non-propagating low-energy vibrational states. (orig.)

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 ...

Sequestration of chelated copper by structural Fe(II): Reductive decomplexation and transformation of Cu{sup II}-EDTA

Energy Technology Data Exchange (ETDEWEB)

He, Hongping [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Wu, Deli, E-mail: wudeli@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Zhao, Linghui [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Luo, Cong [School of Civil and Environmental Engineering, Georgia Institute of Technology, GA 30332 (United States); Dai, Chaomeng; Zhang, Yalei [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China)

2016-05-15

Highlights: • Structural Fe(II) was found to reveal high sequestration potential in various chelated copper. • Chelated copper was reduced to Cu(0) and Cu{sub 2}O by =Fe(II), whcih was oxidized to Fe{sub 2}O{sub 3}·H{sub 2}O. • Both electron transfer and surface =Fe(II) were found to be crucial during chelated copper reduction. • The indispensible role of reductive decomplexation was identified in chelated copper sequestration. - Abstract: Chelated coppers, such as Cu{sup II}-EDTA, are characteristically refractory and difficult to break down because of their high stability and solubility. Cu{sup II}–EDTA sequestration by structural Fe(II) (=Fe(II)) was investigated intensively in this study. Up to 101.21 mgCu(II)/gFe(II) was obtained by =Fe(II) in chelated copper sequestration under near neutral pH condition (pH 7.70). The mechanism of Cu{sup II}-EDTA sequestration by =Fe(II) was concluded as follows: 3Cu{sup II}–EDTA + 7=Fe(II) + 9H{sub 2}O → Cu(0) ↓ + Cu{sub 2}O ↓ (the major product) + 2Fe{sub 2}O{sub 3}·H{sub 2}O ↓ + 3Fe{sup II}–EDTA +14H{sup +} Novel results strongly indicate that Cu{sup II} reductive transformation induced by surface =Fe(II) was mainly responsible for chelated copper sequestration. Cu(0) generation was initially facilitated, and subsequent reduction of Cu(II) into Cu(I) was closely combined with the gradual increase of ORP (Oxidation-Reduction Potential). Cu-containing products were inherently stable, but Cu{sub 2}O would be reoxidized to Cu(II) with extra-aeration, resulting in the release of copper, which was beneficial to Cu reclamation. Concentration diminution of Cu{sup II}–EDTA within the electric double layer and competitive adsorption were responsible for the negative effects of Ca{sup 2+}, Mg{sup 2+}. By generating vivianite, PO{sub 4}{sup 3−} was found to decrease surface =Fe(II) content. This study is among the first ones to identify the indispensible role of reductive decomplexation in chelated copper

DETERMINATION OF Cu, Fe, Mn, Zn AND FREE FATTY ACIDS IN PEQUI OIL

Directory of Open Access Journals (Sweden)

Aparecida M. S. Mimura

2016-06-01

Full Text Available Pequi (Caryocar brasiliense Camb., a typical fruit of the Brazilian Cerrado, is an important source of micronutrients and fatty acids. In this work, a new approach for the acid digestion (using H2SO4, HNO3 and H2O2 of pequi oil samples and the determination of Cu, Fe, Zn and Mn by flame atomic absorption spectrometry (F AAS was employed. Capillary zone electrophoresis (CZE was used for free fatty acid (FFA determination after simple and fast extraction with heated ethanol. Good results regarding precision (RSD < 10%, in most cases, sensitivity and adequate LOD and LOQ values were obtained. The accuracy was evaluated using spike tests and the recoveries were from 97 to 107%. The analytes were investigated in four different pequi oil samples. Fe was the trace element with the highest concentration (from 1.99 to 10.3 mg/100 g, followed by Zn, Mn and Cu (1.15 to 3.19, 0.42 to 0.91 and 0.31 to 0.56 mg/100 g, respectively. The main FFA found were oleic acid and palmitic acid (1.61 to 10.7 and 0.82 to 2.69 g/100 g, respectively, while linoleic acid (0.50 g/100 g was detected in only one sample. The pequi oil chemical composition showed good characteristics to be used as a food additive, in cosmetic formulations and for traditional medicine.

Superconductivity and spin fluctuations in M-Zr metallic glasses (M = Cu, Ni, Co, and Fe)

International Nuclear Information System (INIS)

Altounian, Z.; Strom-Olsen, J.O.

1983-01-01

The superconducting transition temperature, upper critical field, and magnetic susceptibility have been measured in four binary metallic glass systems: Cu-Zr, Ni-Zr, Co-Zr, and Fe-Zr. For each alloy system, a full and continuous range of Zr-rich compositions accessible by melt spinning has been examined. For Cu-Zr, the range is 0.75>x>0.30; for Ni-Zr, 0.80>x>0.30; for Co-Zr, 0.80>x>0.48, and for Fe-Zr, 0.80>x>0.55 (x being the concentration of Zr in at. %). The results show clearly the influence of spin fluctuations in reducing the superconducting transition temperature. The data have been successfully analyzed using a modified form of the McMillan equation together with expressions for the Stoner enhanced magnetic susceptibility and the Ginsburg-Landau-Abrikosov-Gor'kov expression for the upper critical field

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 ).

Production of sulfate radical from peroxymonosulfate induced by a magnetically separable CuFe2O4 spinel in water: Efficiency, stability, and mechanism

KAUST Repository

Zhang, Tao

2013-03-19

A simple, nonhazardous, efficient and low energy-consuming process is desirable to generate powerful radicals from peroxymonosulfate (PMS) for recalcitrant pollutant removal. In this work, the production of radical species from PMS induced by a magnetic CuFe2O4 spinel was studied. Iopromide, a recalcitrant model pollutant, was used to investigate the efficiency of this process. CuFe2O4 showed higher activity and 30 times lower Cu2+ leaching (1.5 μg L-1 per 100 mg L-1) than a well-crystallized CuO at the same dosage. CuFe 2O4 maintained its activity and crystallinity during repeated batch experiments. In comparison, the activity of CuO declined significantly, which was ascribed to the deterioration in its degree of crystallinity. The efficiency of the PMS/CuFe2O4 was highest at neutral pH and decreased at acidic and alkaline pHs. Sulfate radical was the primary radical species responsible for the iopromide degradation. On the basis of the stoichiometry of oxalate degradation in the PMS/CuFe 2O4, the radical production yield from PMS was determined to be near 1 mol/mol. The PMS decomposition involved an inner-sphere complexation with the oxide\\'s surface Cu(II) sites. In situ characterization of the oxide surface with ATR-FTIR and Raman during the PMS decomposition suggested that surface Cu(II)-Cu(III)-Cu(II) redox cycle was responsible for the efficient sulfate radical generation from PMS. © 2013 American Chemical Society.

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)

Magneto-optical response of Cu/NiFe/Cu nanostructure under surface plasmon resonance

Energy Technology Data Exchange (ETDEWEB)

Mahmoodi, S. [Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, 87317 (Iran, Islamic Republic of); Moradi, M., E-mail: m.moradi@kashanu.ac.ir [Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, 87317 (Iran, Islamic Republic of); Mohseni, S.M. [Department of Physics, Shahid Beheshti University, Evin, Tehran, 19839 (Iran, Islamic Republic of)

2016-12-15

In this paper, we present theoretical and experimental studies about the surface plasmon resonance effects on the magneto-optical activity of Cu/NiFe/Cu nanostructures as a function of layers thickness and light incident angle. Device fabrication was done by an oblique deposition technique with RF magnetron sputtering to carefully cover fine step thickness variation of all constituted layers. Angular dependent transverse Kerr response of samples was measured in the Kretschmann configuration at a fixed wavelength of 632 nm. At an optimum layer thickness and incident angle, significant amplification of the transverse Kerr effect was observed. Enhancement in the transverse Kerr effect can be realized by hybridization of surface plasmon excitation and cavity resonance in the plasmonic nanostructure. Experimental results were in qualitative agreement with modeling based on the 4×4 transfer matrix formalism. - Highlights: • Large magneto-optical response in Cu/NiFe/Cu multilayer nanostructure is achieved. • Layer thickness and sequence are studied to find large transverse Kerr signal. • Hybridization of surface plasmon excitation and cavity resonance were done.

Adsorption performance of CuFe2O4/rGO nanocomposites towards organic dye

International Nuclear Information System (INIS)

Tang, Mingyi; Li, Xichuan; Gao, Chunjuan; Li, Xianxian; Qiu, Haixia

2017-01-01

A facile and efficient approach was employed to synthesize CuFe 2 O 4 /rGO (reduced graphene oxide) nanocomposites. The morphology, crystal structure and properties of the prepared CuFe 2 O 4 /rGO nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction and thermo-gravimetric analysis. The CuFe 2 O 4 /rGO nanocomposites were applied as adsorbents to study their adsorption performance for Congo red. The adsorption capacity and recyclability, adsorption dynamics and adsorption models were investigated. The results show that the CuFe 2 O 4 /rGO nanocomposites are efficient and recyclable adsorbents. - Highlights: • CuFe 2 O 4 /rGO was synthesized by a facile hydrothermal route. • As an adsorbent it showed high adsorption capacity to CR. • It was magnetically removable and has high reusability.

Atomic simulations for configurations and solid-liquid interface of Li-Fe and Li-Cu icosahedra

Energy Technology Data Exchange (ETDEWEB)

Yang, Jianyu, E-mail: hnieyjy@aliyun.com [Hunan Institute of Engineering (China); Hu, Wangyu [Hunan University, College of Materials Science and Engineering (China); Dai, Xiongying [Hunan Institute of Engineering, College of Science (China)

2017-04-15

The melting point of Li is lower than that of Fe (or Cu); thus, solid-liquid interfaces can be easily formed on Li-Fe and Li-Cu nanoalloys. In this work, the configurations and solid-liquid interfaces of Li-Fe and Li-Cu icosahedra are studied using Monte Carlo and molecular dynamics methods. The atomic interactions are described by the analytic embedded-atom method. The dependence of composition, temperature, and nanoparticle size on the configurations and thermal stabilities of nanoalloys is discussed. The behavior of the Li-Fe and Li-Cu nanoalloys in segregation, configuration, and thermal stability is investigated. A different behavior of surface segregation of Li atoms is observed for the two types of nanoalloys. The interface between the Li and Fe atoms is clear. Mixing of Li with Cu at larger nanoparticle sizes is found because of low heat of formation in the system. The configurations of the Li-Fe and Li-Cu nanoalloys are related to the competition between surface segregation and alloying. The thermal stability of Li in the two types of nanoalloys is enhanced by the support of the Fe (or Cu) solid substrate.

Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO{sub 2} mediated heterogeneous activation of peroxymonosulfate

Energy Technology Data Exchange (ETDEWEB)

Ding, Yaobin, E-mail: yaobinding@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Tang, Hebin [College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China); Zhang, Shenghua; Wang, Songbo [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Tang, Heqing, E-mail: tangheqing@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China)

2016-11-05

Highlights: • CuFeO{sub 2} microparticles were prepared by a microwave-assisted hydrothermal method. • CuFeO{sub 2} microparticles efficiently catalyzed the activation of peroxymonosulfate. • Quenching experiments confirmed sulfate radicals as the major reactive radicals. • Carbamazepine was rapidly degraded by micro-CuFeO{sub 2}/peroxymonosulfate. • Feasibility of CuFeO{sub 2}/peroxymonosulfate was tested for treatment of actual water. - Abstract: Microscaled CuFeO{sub 2} particles (micro-CuFeO{sub 2}) were rapidly prepared via a microwave-assisted hydrothermal method and characterized by scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. It was found that the micro-CuFeO{sub 2} was of pure phase and a rhombohedral structure with size in the range of 2.8 ± 0.6 μm. The micro-CuFeO{sub 2} efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO{sub 4}·−), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO{sub 2} was observed to be 6.9 and 25.3 times that of micro-Cu{sub 2}O and micro-Fe{sub 2}O{sub 3}, respectively. The enhanced activity of micro-CuFeO{sub 2} for the activation of PMS was confirmed to be attributed to synergistic effect of surface bonded Cu(I) and Fe(III). Sulfate radical was the primary radical species responsible for the CBZ degradation. As a microscaled catalyst, micro-CuFeO{sub 2} can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu{sub 2}O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO{sub 2} was effective in the studied actual aqueous environmental systems.

Moessbauer studies of 57Fe substitution of Cu ions in superconducting oxides

International Nuclear Information System (INIS)

Saitovitch, E.B.

1988-01-01

Since the discovery of high-T c superconductivity in YBa 2 Cu 3 O 7 oxides several studies of metal ions substitutions were reported. The observed depression on T c without a systematic correlation with the charge and magnetic moment of Cu substituents claims for more detailed information about its local properties as can be revealed by 57 Fe Moessbauer spectroscopy. The results for different iron concentrations combined with modifications of the superconducting transition are discussed concerning the presence of magnetic moments on the Fe ions and the preferential occupation of Cu(1) sites, recently confirmed by neutron and electron diffraction experiments. The oxygen coordination for the different iron species are proposed on the basis of their dependence on Fe concentration, their behavior at high temperatures as well as the electron diffraction and electron microscopy measurements reported for Fe: YBa 2 Cu 3 O 7 samples. (author) [pt

Intermartensitic transitions in Ni-Mn-Fe-Cu-Ga Heusler alloys

International Nuclear Information System (INIS)

Khan, Mahmud; Gautam, Bhoj; Pathak, Arjun; Dubenko, Igor; Stadler, Shane; Ali, Naushad

2008-01-01

A series of Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga Heusler alloys have been investigated by means of x-ray diffraction, magnetizations, thermal expansion, and electrical resistivity measurements. In Ni 2 Mn 0.75 Cu 0.25 Ga, martensitic and ferromagnetic transitions occur at the same temperature. Partial substitution of Mn by Fe results in a decrease of the martensitic transition temperature, T M , and an increase of the ferromagnetic transition temperature, T C , resulting in separation of the two transitions. In addition to the martensitic transition, complete thermoelastic intermartensitic transformations have been observed in the Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga samples with x>0.04. An unusual transition is observed in the alloy with x = 0.04. The magnetization curve as a function of increasing temperature shows only one first-order transition in the temperature range 5-400 K, which is identified as a typical coupled magnetostructural martensitic transformation. The magnetization curve as a function of decreasing temperature shows three different transitions, which are characterized as the ferromagnetic transition, the martensitic transition and the intermartensitic transition.

Creep and Oxidation Behavior of Modified CF8C-Plus with W, Cu, Ni, and Cr

Science.gov (United States)

Unocic, Kinga A.; Dryepondt, Sebastien; Yamamoto, Yukinori; Maziasz, Philip J.

2016-04-01

The microstructures of modified CF8C-Plus (Fe-19Cr-12Ni-0.4W-3.8Mn-0.2Mo-0.6Nb-0.5Si-0.9C) with W and Cu (CF8CPWCu) and CF8CPWCu enhanced with 21Cr + 15Ni or 22Cr + 17.5Ni were characterized in the as-cast condition and after creep testing. When imaged at lower magnifications, the as-cast microstructure was similar among all three alloys as they all contained a Nb-rich interdendritic phase and Mn-based inclusions. Transmission electron microscopy (TEM) analysis showed the presence of nanoscale Cu-rich nanoprecipitates distributed uniformly throughout the matrix of CF8CPWCu, whereas in CF8CPWCu22/17, Cu precipitates were found primarily at the grain boundaries. The presence of these nanoscale Cu-rich particles, in addition to W-rich Cr23C6, nanoscale Nb carbides, and Z-phase (Nb2Cr2N2), improved the creep strength of the CF8CPWCu steel. Modification of CF8CPWCu with Cr and Ni contents slightly decreased the creep strength but significantly improved the oxidation behavior at 1073 K (800 °C). In particular, the addition of 22Cr and 17.5Ni strongly enhanced the oxidation resistance of the stainless steel resulting in a 100 degrees or greater temperature improvement, and this composition provided the best balance between improving both mechanical properties and oxidation resistance.

Effects of Cu substitution for Fe on the glass-forming ability and soft magnetic properties for Fe-based bulk metallic glasses

International Nuclear Information System (INIS)

Dou, Lintao; Liu, Haishun; Hou, Long; Xue, Lin; Yang, Weiming; Zhao, Yucheng; Chang, Chuntao

2014-01-01

The effects of Cu substitution for Fe on the glass-forming ability (GFA) and soft magnetic properties for Fe 72−x Cu x B 20 Si 4 Nb 4 (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) bulk metallic glasses (BMGs) are investigated. It is found that the investigated BMGs exhibit large GFA as well as excellent soft magnetic properties, and proper substitution of Fe by Cu improves the saturation magnetization, coercive force, and effective permeability without obvious deterioration of the GFA. - Highlights: • Fully glassy rods of Fe 72−x Cu x B 20 Si 4 Nb 4 BMGs were produced above 1 mm in diameter. • Investigated BMGs exhibit large glass-forming ability and excellent soft magnetic properties. • Proper Cu substitution improves magnetic properties without obvious deterioration of glass-forming ability

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.)

Influence of surface topography on RBS measurements: case studies of (Cu/Fe/Pd) multilayers and FePdCu alloys nanopatterned by self-assembly

Science.gov (United States)

Krupinski, M.; Perzanowski, M.; Zabila, Y.; Zarzycki, A.; Marszałek, M.

2017-03-01

In this paper the influence of surface topography on Rutherford backscattering spectrometry (RBS) is discussed. (Cu/Fe/Pd) multilayers with total thickness of about 10 nm were deposited by physical vapor deposition on self-organized array of SiO2 nanoparticles with the size of 50 nm and 100 nm. As a reference, the multilayered systems were also prepared on flat substrates under the same conditions. After the deposition, morphology of the systems was studied by scanning electron microscopy (SEM), while chemical analysis was performed using Rutherford backscattering spectrometry. It was found that the RBS spectra and determined compositions for flat and patterned multilayers differ. The difference is discussed by taking into account the effect of additional inelastic scattering and energy straggling occurring due to developed topography of patterned systems. Then, the multilayers were annealed in 600 °C in order to obtain FePdCu alloy. The phenomenon of solid-state dewetting resulted in the formation of isolated alloy islands on the top of SiO2 nanoparticles. The SEM and RBS analysis were repeated showing correlation between the size distribution of obtained alloy islands and broadening of peaks appearing in RBS spectra. Invited talk at 8th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN2016), 8-12 November 2016, Ha Long City, Vietnam.

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.

Simple electrodepositing of CoFe/Cu multilayers: Effect of ferromagnetic layer thicknesses

Energy Technology Data Exchange (ETDEWEB)

Tekgül, Atakan, E-mail: atakantekgul@gmail.com [Akdeniz University, Physics Department, Science Faculty, TR-07058 Antalya (Turkey); Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Alper, Mürsel [Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Kockar, Hakan [Balikesir University, Physics Department, Science and Literature Faculty, TR-10145 Balikesir (Turkey)

2017-01-01

The CoFe/Cu magnetic multilayers were produced by changing CoFe ferromagnetic layers from 3 nm to 10 nm using electrodeposition. By now, the thinnest Cu (0.5 nm) layer thicknesses were used to see whether the GMR effect in the multilayers can be obtained or not since the pinning of non-magnetic layer between the ferromagnetic layers is required. For the proper depositions, the cyclic voltammograms was used, and the current–time transients were obtained. The Cu and CoFe layers were deposited at a cathode potential of −0.3 and −1.5 V with respect to saturated calomel electrode, respectively. From the XRD patterns, the multilayers were shown to be fcc crystal structures. For the magnetization measurements, saturation magnetization increases from 160 to 600 kA/m from 3 to 8 nm ferromagnetic layer thicknesses. And, the coercivity values increase until the 8 nm of the CoFe layer thickness. It is seen that the thin Cu layer (fixed at 0.5 nm) and pinholes support the random magnetization orientation and thus all multilayers exhibited the giant magnetoresistance (GMR) effect, and the highest GMR value was observed about 5.5%. And, the variation of GMR field sensitivity was calculated. The results show that the GMR and GMR sensitivity are compatible among the multilayers. The CoFe/Cu magnetic multilayers having GMR properties are used in GMR sensors and hard disk drive of the nano-technological devices. - Highlights: • The much thinner (0.5 nm) Cu layer was used to obtain the GMR effect on the electrodeposited CoFe/Cu multilayers. • All samples exhibited GMR and the maximum GMR value was 5.5%. • The M{sub s} and the H{sub c} changed with increasing magnetic layer thickness.

Magnetic and catalytic properties of inverse spinel CuFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Anandan, S., E-mail: sanand@nitt.edu [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China); Selvamani, T.; Prasad, G. Guru [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Asiri, A.M. [The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21413 (Saudi Arabia); Wu, J.J., E-mail: jjwu@fcu.edu.tw [Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China)

2017-06-15

Highlights: • Copper ferrite (CuFe{sub 2}O{sub 4}) nanoparticles were synthesized via citrate-nitrate combustion method. • Spectroscopic information’s have found that CuFe{sub 2}O{sub 4} nanoparticles as an inverse spinel structure. • Magnetic study exhibits CuFe{sub 2}O{sub 4} nanoparticles have ferromagnetic behavior. • CuFe{sub 2}O{sub 4} nanoparticles employed for photocatalytic decolourisation of methylene blue under visible light irradiation. - Abstract: In this research, inverse spinel copper ferrite nanoparticles (CuFe{sub 2}O{sub 4} NPs) were synthesized via citrate-nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M{sub s} = 20.62 emu g{sup −1}), remnant magnetization (M{sub r} = 11.66 emu g{sup −1}) and coercivity (H{sub c} = 63.1 mTesla) revealed that the synthesized CuFe{sub 2}O{sub 4} NPs have a typical ferromagnetic behaviour. Also tested CuFe{sub 2}O{sub 4} nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant.

Magnetic and structural properties of Cu0.85Fe0.15O system synthesized by co-precipitation

International Nuclear Information System (INIS)

Colorado, H. D.; Pérez Alcázar, G. A.

2011-01-01

Cu 0.94 Fe 0.06 O and Cu 0.85 Fe 0.15 O samples were synthesized by using the co-precipitation chemical method. Starting from aqueous solutions of copper nitrate, CuO (NO 3 ) 2 3H 2 O, iron nitrate, Fe (NO 3 ) 3 9H 2 O and sodium hydroxide as precipitating agent, NaOH. The precipitate of three samples for Cu 0.94 Fe 0.06 O and five for Cu 0.85 Fe 0.15 O of fine powder were calcined for 5 h at different temperatures. The obtained X rays diffraction patterns refined by the Rietveld method show the CuO characteristic pattern, showing that the Fe atoms enter to replace Cu atoms. Furthermore, it was obtained that the crystallite size decreases with calcination temperatures for Cu 0.94 Fe 0.06 O. The transmission Mössbauer spectroscopy showed that the samples present a disordered paramagnetic behavior due to the big value of the half-width of line of the quadrupolar splitting. Vibrating sample magnetometry confirms the paramagnetic character. The XRD results indicate that the material is nanostructured, due that the crystallite sizes are of the order of 10 nm for Cu 0.94 Fe 0.06 O and 40 nm for Cu 0.85 Fe 0.15 O.

Microstrucural characterization of gas atomized Fe{sub 73.5}Si{sub 13.5}B{sub 9}Nb{sub 3}Cu{sub 1} and Fe{sub 97}Si{sub 3} alloys

Energy Technology Data Exchange (ETDEWEB)

Garcia-Escorial, A., E-mail: age@cenim.csic.es [CENIM-CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Lieblich, M. [CENIM-CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Lopez, M.; Marin, P. [Instituto de Magnetismo Aplicado, P.O. Box 155, 28230 Madrid (Spain)

2011-06-15

Research highlights: > Two FeSi-base alloys as precursors for small dimension soft magnets. > Small particles rapidly solidified by gas atomisation. > Increase effective magnetic anisotropy constant by alloying segregation. > Magnetic hardenning due to volume decrease. - Abstract: Powder particles of Fe{sub 73.5}Si{sub 13.5}B{sub 9}Nb{sub 3}Cu{sub 1} and Fe{sub 97}Si{sub 3} soft magnetic alloys have been prepared by gas atomization. The gas atomized powder was microstructurally characterized and the dependence of coercivity with the composition and powder particle size investigated. As-atomized powder particles of both compositions were constituted by a bcc {alpha}-Fe (Si) solid solution. The Fe{sub 73.5}Si{sub 13.5}B{sub 9}Nb{sub 3}Cu{sub 1} powder particles presented a grain microstructure with dendrite structure, which dendrite arms were enriched in Nb. The coercivity increased as the particle size decreased, with a minimum coercivity, of 5 Oe, measured in the Fe{sub 97}Si{sub 3} alloy in the range of 50-100 {mu}m powder particle size. The coercive fields were quite higher in the Fe{sub 73.5}Si{sub 13.5}B{sub 9}Nb{sub 3}Cu{sub 1} than in the Fe{sub 97}Si{sub 3} powder, due to the Nb addition, which produced a phase segregation that leads to a noticeable magnetic hardening.

Microstructural behavior of iron and bismuth added Sn-1Ag-Cu solder under elevated temperature aging

Energy Technology Data Exchange (ETDEWEB)

Ali, Bakhtiar, E-mail: engrbakhtiaralikhan@gmail.com; Sabri, Mohd Faizul Mohd, E-mail: faizul@um.edu.my; Jauhari, Iswadi, E-mail: iswadi@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2016-07-19

An extensive study was done to investigate the microstructural behavior of iron (Fe) and bismuth (Bi) added Sn-1Ag-0.5Cu (SAC105) under severe thermal aging conditions. The isothermal aging was done at 200 °C for 100 h, 200 h, and 300 h. Optical microscopy with cross-polarized light revealed that the grain size significantly reduces with Fe/Bi addition to the base alloy SAC105 and remains literally the same after thermal aging. The micrographs of field emission scanning electron microscopy (FESEM) with backscattered electron detector and their further analysis via imageJ software indicated that Fe/Bi added SAC105 showed a significant reduction in the IMCs size (Ag{sub 3}Sn and Cu{sub 6}Sn{sub 5}), especially the Cu{sub 6}Sn{sub 5} IMCs, as well as β-Sn matrix and a refinement in the microstructure, which is due to the presence of Bi in the alloys. Moreover, their microstructure remains much more stable under severe thermal aging conditions, which is because of the presence of both Fe and Bi in the alloy. The microstructural behavior suggests that Fe/Bi modified SAC105 would have much improved reliability under severe thermal environments. These modified alloys also have relatively low melting temperature and low cost.

Estimated daily intake of Fe, Cu, Ca and Zn through common cereals in Tehran, Iran.

Science.gov (United States)

Kashian, S; Fathivand, A A

2015-06-01

This paper presents the findings of study undertaken to estimate the dietary intake of iron (Fe), copper (Cu), calcium (Ca) and zinc (Zn) through common cereals in Tehran, Iran. 100 samples of rice, wheat and barley were collected from various brands between August and October 2013. The samples were analyzed performing instrumental neutron activation analysis (INAA). The dietary intake for adults was estimated by a total cereal study. Calculations were carried out on the basis of the reported adults' average food consumption rate data. The total daily intake estimated in mgd(-1) for Tehran population were 3.6 (Fe), 10.2 (Zn), 0.3 (Cu) and 234.5 (Ca). Wheat showed the highest contribution to Zn, Cu and Ca intakes. Furthermore, intakes were compared with recommended dietary allowance (RDA). Zn total intake (10.2mgd(-1)) was comparable with RDA values for males (11mgd(-1)) and was higher than recommended value for females (8mgd(-1)). The intakes of other studied elements were below the respective RDAs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

Directory of Open Access Journals (Sweden)

Soheil Sobhanardakani

2014-09-01

Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

Antifriction coating of Cu-Fe-Al-Pb system for plain bearings

Science.gov (United States)

Kotenkov, Pavel; Kontsevoi, Yurii; Mejlakh, Anna; Pastukhov, Eduard; Shubin, Alexey; Goyda, Eduard; Sipatov, Ivan

2017-09-01

Aluminium, copper and their compounds are used in common as basis for antifriction coatings of plain bearings. Antifriction testing of plain bearings (based on Al and Cu) made by leading automotive manufacturers from Germany, Japan, USA, United Kingdom and Russia were carried out to make judicious selection of basis for development of new antifriction material. Testing was carried out using friction machine. It was defined that materials based on Cu provide better durability and robustness of plain bearings in comparison with Al based ones. The new antifriction composite coatings based on copper were developed taking into account the requirements specified for plain bearings of internal-combustion engine. Pilot samples of plain bearings with antifriction coatings of Cu-Fe-Al-Pb system were produced. The antifriction composite having Cu-5Fe-5Al5Fe2-10Pb (mass %) composition has demonstrated low friction factor and high wear-resistance. Metallographic analysis of pilot samples was carried out by means of optical and scanning electron microscopy.

Electrical characteristic of spin coated Fe-Porphyrin on Cu substrates

Energy Technology Data Exchange (ETDEWEB)

Utari, E-mail: utari@ugm.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia); Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia); Kusumandari,; Purnama, Budi, E-mail: bpurnama@mipa.uns.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia); Mudasir [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia); Abraha, Kamsul [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia)

2016-06-17

This paper describes the electrical-characteristics of Fe-Porphyrin thin films on Cu substrates. The thin layer samples used were deposited by spin coating methods on Cu-substrates at room temperature with and without induced magnetic field in the plane direction of the surface films. Fe-porphyrin was dissolved in chloroform and mixed with a magnetic stirrer for 60 min at a rotational speed of 200 rpm. The experimental results show that the mobility carrier charge of the Fe-Porphyrin layer with induced magnetic field during deposition has lower value than that without induced magnetic field case. The decrease of the mobility can be attribute to the change of the surface morphology in Fe-porphyrin films by means of increase in the nano-granular/nano-molecular size caused by the induce magnetic field.

Effect of Soil Parameters on the Kinetics of the Displacement of Fe from FeEDDHA Chelates by Cu

NARCIS (Netherlands)

Schenkeveld, W.D.C.; Reichwein, A.M.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

2012-01-01

In soil application, o,o-FeEDDHA (iron (3+) ethylene diamine-N,N'-bis(2-hydroxy phenyl acetic acid) complex) is the active ingredient of FeEDDHA chelate-based Fe fertilizers. The effectiveness of o,o-FeEDDHA is potentially compromised by the displacement of Fe from FeEDDHA by Cu. The actual impact

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.)

Magnetic properties of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yao, Jinlei [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Quezado, S.; Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

2015-12-15

Magnetic properties and magnetocaloric effect of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds have been investigated. Magnetic measurements of RNi{sub 3}TSi display the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Graphical abstract: Magnetic measurements of RNi{sub 3}TSi show the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of 'RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi'. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Highlights: • CaCu{sub 5}-type RNi{sub 3}TSi show ferromagnetic ordering (R=Gd, Tb, T=Mn–Co, Cu). • Curie point increases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • MCE decreases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. • The coercive field of TbNi{sub 3}MnSi and TbNi{sub 3}FeSi reach 13 kOe and 16 kOe at 5 K.

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.

CuFeO2 formation using fused deposition modeling 3D printing and sintering technique

Science.gov (United States)

Salea, A.; Dasaesamoh, A.; Prathumwan, R.; Kongkaew, T.; Subannajui, K.

2017-09-01

CuFeO2 is a metal oxide mineral material which is called delafossite. It can potentially be used as a chemical catalyst, and gas sensing material. There are methods to fabricate CuFeO2 such as chemical synthesis, sintering, sputtering, and chemical vapor deposition. In our work, CuFeO2 is prepared by Fused Deposition Modeling (FDM) 3D printing. The composite filament which composed of Cu and Fe elements is printed in three dimensions, and then sintered and annealed at high temperature to obtain CuFeO2. Suitable polymer blend and maximum percent volume of metal powder are studied. When percent volume of metal powder is increased, melt flow rate of polymer blend is also increased. The most suitable printing condition is reported and the properties of CuFeO2 are observed by Scanning Electron Microscopy, and Dynamic Scanning Calorimeter, X-ray diffraction. As a new method to produce semiconductor, this technique has a potential to allow any scientist or students to design and print a catalyst or sensing material by the most conventional 3D printing machine which is commonly used around the world.

Redox chemistry of a binary transition metal oxide (AB2O4): a study of the Cu(2+)/Cu(0) and Fe(3+)/Fe(0) interconversions observed upon lithiation in a CuFe2O4 battery using X-ray absorption spectroscopy.

Science.gov (United States)

Cama, Christina A; Pelliccione, Christopher J; Brady, Alexander B; Li, Jing; Stach, Eric A; Wang, Jiajun; Wang, Jun; Takeuchi, Esther S; Takeuchi, Kenneth J; Marschilok, Amy C

2016-06-22

Copper ferrite, CuFe2O4, is a promising candidate for application as a high energy electrode material in lithium based batteries. Mechanistic insight on the electrochemical reduction and oxidation processes was gained through the first X-ray absorption spectroscopic study of lithiation and delithiation of CuFe2O4. A phase pure tetragonal CuFe2O4 material was prepared and characterized using laboratory and synchrotron X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. Ex situ X-ray absorption spectroscopy (XAS) measurements were used to study the battery redox processes at the Fe and Cu K-edges, using X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and transmission X-ray microscopy (TXM) spectroscopies. EXAFS analysis showed upon discharge, an initial conversion of 50% of the copper(ii) to copper metal positioned outside of the spinel structure, followed by a migration of tetrahedral iron(iii) cations to octahedral positions previously occupied by copper(ii). Upon charging to 3.5 V, the copper metal remained in the metallic state, while iron metal oxidation to iron(iii) was achieved. The results provide new mechanistic insight regarding the evolution of the local coordination environments at the iron and copper centers upon discharging and charging.

Safe-by-Design CuO Nanoparticles via Fe-Doping, Cu-O Bond Length Variation, and Biological Assessment in Cells and Zebrafish Embryos.

Science.gov (United States)

Naatz, Hendrik; Lin, Sijie; Li, Ruibin; Jiang, Wen; Ji, Zhaoxia; Chang, Chong Hyun; Köser, Jan; Thöming, Jorg; Xia, Tian; Nel, Andre E; Mädler, Lutz; Pokhrel, Suman

2017-01-24

The safe implementation of nanotechnology requires nanomaterial hazard assessment in accordance with the material physicochemical properties that trigger the injury response at the nano/bio interface. Since CuO nanoparticles (NPs) are widely used industrially and their dissolution properties play a major role in hazard potential, we hypothesized that tighter bonding of Cu to Fe by particle doping could constitute a safer-by-design approach through decreased dissolution. Accordingly, we designed a combinatorial library in which CuO was doped with 1-10% Fe in a flame spray pyrolysis reactor. The morphology and structural properties were determined by XRD, BET, Raman spectroscopy, HRTEM, EFTEM, and EELS, which demonstrated a significant reduction in the apical Cu-O bond length while simultaneously increasing the planar bond length (Jahn-Teller distortion). Hazard screening was performed in tissue culture cell lines and zebrafish embryos to discern the change in the hazardous effects of doped vs nondoped particles. This demonstrated that with increased levels of doping there was a progressive decrease in cytotoxicity in BEAS-2B and THP-1 cells, as well as an incremental decrease in the rate of hatching interference in zebrafish embryos. The dissolution profiles were determined and the surface reactions taking place in Holtfreter's solution were validated using cyclic voltammetry measurements to demonstrate that the Cu + /Cu 2+ and Fe 2+ /Fe 3+ redox species play a major role in the dissolution process of pure and Fe-doped CuO. Altogether, a safe-by-design strategy was implemented for the toxic CuO particles via Fe doping and has been demonstrated for their safe use in the environment.

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.

Crystal structure and magnetism of layered perovskites compound EuBaCuFeO5

Science.gov (United States)

Lal, Surender; Mukherjee, K.; Yadav, C. S.

2018-04-01

Layered perovskite compounds have interesting multiferroic properties.YBaCuFeO5 is one of the layered perovskite compounds which have magnetic and dielectric transition above 200 K. The multiferroic properties can be tuned with the replacement of Y with some other rare earth ions. In this manuscript, structural and magnetic properties of layered perovskite compound EuBaCuFeO5 have been investigated. This compound crystallizes in the tetragonal structure with P4mm space group and is iso-structural with YBaCuFeO5. The magnetic transition has been found to shift to 120 K as compared to YBaCuFeO5 which has the transition at 200 K. This shift in the magnetic transition has been ascribed to the decrease in the chemical pressure that relaxes the magnetic moments.

Cu(2+) and Fe(2+) mediated photodegradation studies of soil-incorporated chlorpyrifos.

Science.gov (United States)

Rafique, Nazia; Tariq, Saadia R; Ahad, Karam; Taj, Touqeer

2016-03-01

The influences of Cu(2+) and Fe(2+) on the photodegradation of soil-incorporated chlorpyrifos were investigated in the present study. The soil samples spiked with chlorpyrifos and selected metal ions were irradiated with UV light for different intervals of time and analyzed by HPLC. The unsterile and sterile control soil samples amended with pesticides and selected metals were incubated in the dark at 25 °C for the same time intervals. The results of the study evidenced that photodegradation of chlorpyrifos followed the first-order kinetics. The dissipation t0.5 of chlorpyrifos was found to decrease from 41 to 20 days under UV irradiation. The rate of chlorpyrifos photodegradation was increased in the presence of both metals, i.e., Cu(2+) and Fe(2+). Thus, initially observed t0.5 of 19.8 days was decreased to 4.39 days in the case of Cu(+2) and 19.25 days for Fe(+2). Copper was found to increase the rate of photodegradation by 4.5 orders of magnitude while the microbial degradation of chlorpyrifos was increased only twofold. The microbial degradation of chlorpyrifos was only negligibly affected by Fe(2+) amendment. The studied trace metals also affected the abiotic degradation of the pesticide in the order Cu(2+) > Fe(2+).

Interdiffusion coefficients and atomic mobilities in fcc Cu-Fe-Mn alloys

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Li J.

2014-01-01

Full Text Available In the present work, the interdiffusion coefficients in fcc Cu-Fe-Mn alloys were experimentally determined via a combination of solid/solid diffusion couples, electron probe microanalysis (EPMA technique and Matano-Kirkaldy method. Based on the reliable thermodynamic description of fcc phase in the Cu-Fe-Mn system available in the literature as well as the ternary diffusion coefficients measured in the present work, the atomic mobilities in fcc Cu-Fe-Mn alloys were assessed by utilizing the DICTRA (Diffusion Controlled TRAnsformation software package. The calculated interdiffusion coefficients based on the assessed atomic mobilities agree well with most of the experimental data. The comprehensive comparison between various model-predicted diffusion properties and the measured data, including the concentration penetration profiles, interdiffusion flux profile, and diffusion paths, further verify the reliability of the presently obtained atomic mobilities.

Synthesis and magnetic properties of prussian blue modified Fe nanoparticles

International Nuclear Information System (INIS)

Arun, T.; Prakash, K.; Justin Joseyphus, R.

2013-01-01

Fe nanoparticles are prepared using a unique polyol process and modified with prussian blue (PB) at various concentrations. The presence of PB in the Fe nanoparticles are confirmed from thermal, Fourier transform infrared spectroscopy and electron microscopic analyses. The prussian blue existed on ;the surface of the nanoparticles when the concentration is 200 μM and in excess with 1000 μM. ;Fe nanoparticles are reduced in size using Pt as nucleating agent and modified with the optimum concentration of PB. The saturation magnetization decreases with the concentration of PB whereas the coercivity is influenced by the size of the Fe nanoparticles. The presence of oxide layer in Fe nanoparticles helps in the surface modification with PB. The Fe nanoparticles of particle size 53 nm modified with 200 μM of PB showed a saturation magnetization of 110 emu/g. The magnetic properties suggest that the PB modified Fe nanoparticles are better candidates for detoxification applications. - Highlights: • Fe nanoparticles surface modified with prussian blue (PB) were synthesized. • Optimum PB concentration on size reduced Fe showed better magnetic properties. • Coercivity decreased with increasing concentration of PB. • Fe-PB nanoparticles could be used for detoxification applications

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Science.gov (United States)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

Determination of Cu, Fe, Zn Elements in Soil, Root Tea Plants, Tea Leaves, and Tea Beverage

International Nuclear Information System (INIS)

Supriyanto; Zainul-Kamal

2006-01-01

One of the causes of land quality damage was due to the pollution of Cu, Fe, and Zn so that it could directly and also indirectly cause the occurrence of pollution of plants which is growing on it for example tea plant that has been used by society for making of tea beverage. The sampling of soil, root tea plants, tea leaves and tea beverage samples were done in June, 2005 at sub district of Keparakan, Temanggung, Central Java. The purpose of research was to determine the content of Cu, Fe and Zn in soil, root tea plants, tea leaves and tea beverage. The research was done by digesting the sample with nitric acid until the clear solution was obtained, then it was added by aquabidest until 10.0 ml. Determination of Cu, Fe and Zn content used AAS instrument. The average concentration of Cu Fe and Zn obtained in deep soil samples area 0.155 ± 0.005 ppm, 127.16 ± 2.65 ppm, and 0.68 ± 0.02 ppm respectively, in surface soil samples are 0.355 ± 0.025 ppm, 360.59 ± 13.17 ppm and 0.78 ± 0.01 ppm respectively, in root of tea plants samples area 0.241 ± 0.098 ppm, 13.16 ± 1.34 ppm and 2.64 ± 0.06 ppm respectively, in tea leaves are 0.211 ± 0.013 ppm, 3.35 ± 0.886 ppm, and 0.795 ± 0.016 ppm respectively and in tea beverage 0.142 ± 0.086 ppm, 6.11 ± 0.35 ppm and 0.66 ± 0.02 ppm respectively. (author)

Determination of Ca, Cu, Fe and Pb in sugarcane raw spirits by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Lorenzo, Magdalena; Reyes, Arlyn; Blanco, Idania; Vasallo, Maria C

2010-01-01

The determination of Ca, Cu, Fe and Pb in sugarcane raw spirits by atomic absorption spectrophotometry was carried out. For 20 μL injected sample, calibration within the 0,5-25,0 mg. L -1 Ca; 0,25-5,0 mg. L -1 Cu, Pb and Cu intervals were established using the ratios Cu, Ca, Fe and Pb absorbance versus analyte concentration, respectively. Typical linear correlations of r = 0,999 were obtained. The proposed method was applied for the direct determination of Ca, Cu, Fe and Pb in sugar cane spirits, and in samples. The results obtained were in accordance to those obtained at 95% confidence level

Influences on Distribution of Solute Atoms in Cu-8Fe Alloy Solidification Process Under Rotating Magnetic Field

Science.gov (United States)

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

2018-05-01

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

Facile synthesis of Fe-incorporated CuO nanoarrays with enhanced electrochemical performance for lithium ion full batteries

Energy Technology Data Exchange (ETDEWEB)

Heng, Bojun [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Department of Applied Physics, Wuhan University of Science and Technology, Wuhan, 430065 (China); Qing, Chen; Wang, Hai; Sun, Daming; Wang, Bixiao [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Tang, Yiwen, E-mail: ywtang@phy.ccnu.edu.cn [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China)

2015-11-15

CuO nanoarrays (CNAs) and Fe-incorporated CuO nanoarrays (FCNAs) were fabricated by hydrothermal method. Addition of Fe salt to the reaction mixture allowed the introduction of iron oxide onto the CNAs surface, which was characterized by XPS and HRTEM. Introducing Fe ion into reaction precursor significantly affected not only the morphologies of as-prepared products but also their electrochemical performance as anode for lithium ion full battery. The FCNAs electrodes showed higher specific capacity and better capacity retention at different current densities than that of CNAs. - Highlights: • Fe-incorporated CuO nanoarrays were fabricated by hydrothermal method. • Fe salt in reaction mixture leads to iron oxides forming on the surface of CuO. • Fe-incorporating improves the lithium ion battery performance of CuO anodes.

Activity of Aniline Methylation over Fe-Cu-Cr Ternary Spinel Systems

Directory of Open Access Journals (Sweden)

Reni George

2014-03-01

Full Text Available A series of spinels having thegeneral formula CuCr2-xFexO4 with x=0.25,0.75, 1.25, 1.75 were prepared by co-precipitation method. The catalysts werecharacterized by various physico-chemical methods like XRD, BET, UV-DRS, SEM,EDX, TPD etc. The reaction of aniline with methanol was studied in a fixed-bedreactor system as a potential source for the production of various methylanilines. It was observed that systems possessing low ‘x’ values are highlyselective and active for N-monoalkylation of aniline leading toN-methylaniline. Reaction parameters were properly varied to optimize thereaction conditions for obtaining N-methylaniline selectively and in betteryield. Among the systems CuCr1.75Fe0.25O4 isremarkable due to its very high activity and excellent stability. Under theoptimized conditions N-methylaniline selectivity exceeded 91%. CuCr1.25Fe0.75O4gives better conversion than CuCr1.75Fe0.25O4in CuCr2-xFexO4 series. The Lewis acid sitesof the catalysts are mainly responsible for the good catalytic performance. © 2014 BCREC UNDIP. All rights reservedSubmitted: 18th July 2013; Revised: 5th November 2013; Accepted: 1st December 2013[How to Cite: George, R., George, K., Sugunan, S. (2014. Activity of Aniline Methylation over Fe-Cu-Cr Ternary Spinel Systems. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 39-44. (doi:10.9767/bcrec.9.1.5169.39-44][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5169.39-44] 

Glass forming ability of the Fe-Zr-Cu system studied by thermodynamic calculation and ion beam mixing

International Nuclear Information System (INIS)

Wang, T.L.; Liu, B.X.

2009-01-01

The glass forming ability/range (GFA/GFR) of the Fe-Zr-Cu system was studied by thermodynamic calculation based on Miedema's model and Alonso's method. It is found that when the atomic concentration of Zr is between 34% and 56%, no matter what the atomic concentrations of Fe and Cu are, amorphous phase could be obtained, thus the atomic mismatch playing a dominating role in influencing the GFA. While the atomic concentration of Zr is out of the above range, the GFA is highly influenced by the immiscibility between Fe and Cu. Experimentally, ion beam mixing was carried out to synthesize amorphous alloys in the Fe-Zr-Cu system. It turned out that in the samples with overall compositions of Fe 26 Zr 36 Cu 38 , Fe 52 Zr 27 Cu 21 and Fe 21 Zr 60 Cu 19 , which are located in or at the edge of the calculated GFR, amorphous phases were indeed obtained, whereas no amorphous phase was obtained if the overall compositions were located outside of the predicted region favoring for amorphous alloy formation, showing a good agreement between the experimental results and the thermodynamic calculation.

Fe and Cu in Si: Lattice sites and trapping at implantation-related defects

International Nuclear Information System (INIS)

Wahl, U.; Correia, J.G.; Rita, E.; Araujo, J.P.; Soares, J.C.

2006-01-01

We have used the emission channeling technique in order to study the lattice sites of radioactive 59 Fe and 67 Cu following 60 keV ion implantation into Si single crystals at fluences around 10 12 -10 14 cm -2 . We find that in the room temperature as-implanted state in high-resistivity Si both Fe and Cu occupy mainly lattice sites displaced around 0.05 nm (0.5 A) from substitutional positions. Both are released from these positions during annealing at temperatures between 300 deg. C and 600 deg. C. Fe is then found mainly on near-tetrahedral interstitial sites and further annealing causes it to be increasingly incorporated on ideal substitutional sites, on which it is stable to around 800 deg. C. We have strong indications that during annealing around 600 deg. C, along with the dominance of interstitial Fe, a redistribution towards the surface takes place, suggesting that the subsequent formation of ideal substitutional Fe may be related to the trapping of Fe at R p /2, half of its implanted depth. Possible R p /2 trapping might also have taken place in our Cu experiments but appears to be less efficient since Cu tended to escape to the bulk of the samples

Heptanuclear Fe5Cu2-Phenylgermsesquioxane containing 2,2'-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C-H Compounds.

Science.gov (United States)

Bilyachenko, Alexey N; Khrustalev, Victor N; Zubavichus, Yan V; Shul'pina, Lidia S; Kulakova, Alena N; Bantreil, Xavier; Lamaty, Frédéric; Levitsky, Mikhail M; Gutsul, Evgeniy I; Shubina, Elena S; Shul'pin, Georgiy B

2018-01-02

A new representative of an unusual family of metallagermaniumsesquioxanes, namely the heterometallic cagelike phenylgermsesquioxane (PhGeO 2 ) 12 Cu 2 Fe 5 (O)OH(PhGe) 2 O 5 (bipy) 2 (2), was synthesized and structurally characterized. Fe(III) ions of the complex are coordinated by oxa ligands: (i) cyclic (PhGeO 2 ) 12 and acyclic (Ph 2 Ge 2 O 5 ) germoxanolates and (ii) O 2- and (iii) HO - moieties. In turn, Cu(II) ions are coordinated by both oxa (germoxanolates) and aza ligands (2,2'-bipyridines). This "hetero-type" of ligation gives in sum an attractive pagoda-like molecular architecture of the complex 2. Product 2 showed a high catalytic activity in the oxidation of alkanes to the corresponding alkyl hydroperoxides (in yields up to 30%) and alcohols (in yields up to 100%) and in the oxidative formation of benzamides from alcohols (catalyst loading down to 0.4 mol % in Cu/Fe).

Effect of nickel addition on mechanical properties of powder forged Fe-Cu-C

Science.gov (United States)

Archana Barla, Nikki

2018-03-01

Fe-Cu-C system is very popular in P/M industry for its good compressibility and dimensional stability with high strength. Fe-Cu-C is a structural material and is used where high strength with high hardness is required. The composition of powder metallurgy steel plays a vital role in the microstructure and physical properties of the sintered component. Fe-2Cu-0.7C-Ni alloy with varying nickel composition (0%, 0.5%, 1.0%, 1.5%, 2.0%, and 3.0%) wt. % was prepared by powder metallurgy (P/M) sinter forging process. The present work discuss the effect of varying nickel content on microstructure and mechanical properties.

TEM study on a new Zr-(Fe, Cu) phase in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe-0.1Cu alloy

Science.gov (United States)

Liu, Yushun; Qiu, Risheng; Luan, Baifeng; Hao, Longlong; Tan, Xinu; Tao, Boran; Zhao, Yifan; Li, Feitao; Liu, Qing

2018-06-01

A new Zr-(Fe, Cu) phase was found in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe- 0.1Cu alloy and alloys aged at 580 °C for 10min, 2 h and 10 h. Electron diffraction experiment shows the crystal structure of this phase to be body-centered tetragonal with unit cell dimensions determined to be a = b = 6.49 Å, c = 5.37 Å. Its possible space groups have been discussed and the reason accounting for its formation is believed to be the addition of Cu according to the atom-level images. In addition, no crystal structural or chemical composition changes were observed throughout the aging process.

Transverse excitations in liquid Fe, Cu and Zn

International Nuclear Information System (INIS)

Hosokawa, S; Inui, M; Kajihara, Y; Tsutsui, S; Baron, A Q R

2015-01-01

Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering spectra of liquid Fe, Cu and Zn. From the analysis of current correlation functions, we concluded that TA excitation modes can experimentally be detected through the quasi-TA branches in the longitudinal current correlation spectra in these liquid metals. The microscopic elastic constants are estimated and a characteristic difference from macroscopic polycrystalline value was found in Poisson's ratio of liquid Fe, which shows an extremely softer value of ∼0.38 compared with the macroscopic value of ∼0.275. The lifetime of the TA modes were determined to be ∼0.45 ps for liquid Fe and Cu and ∼0.55 ps for liquid Zn, reflecting different interatomic correlations between liquid transition metals and non-transition metals. The propagation length of the TA modes are ∼0.85 nm in all of liquid metals, corresponding to the size of icosahedral or similar size of cages formed instantaneously in these liquid metals. (paper)

The mechanical and electronic properties of Al/TiC interfaces alloyed by Mg, Zn, Cu, Fe and Ti: First-principles study

International Nuclear Information System (INIS)

Sun, Ting; Wu, Xiaozhi; Wang, Rui; Li, Weiguo

2015-01-01

The adhesion and ductility of (100) and (110) Al/TiC interfaces alloyed by Mg, Zn, Cu, Fe, and Ti have been investigated using first-principles methods. Fe and Ti can enhance the adhesion of (100) and (110) interfaces. Mg and Zn have the opposite effect. Interfacial electronic structures have been created to analyze the changes of the work of adhesion. It is found that more charge is accumulated at interfaces alloyed by Fe and Ti compared with pure Al/TiC. There is also an obvious downward shift in the Fermi energy of Fe, Ti at the interface. Furthermore, the unstable stacking fault energies of the interfaces are calculated; the results demonstrate that the preferred slip direction is the 〈110〉 direction for (100) and (110) Al/TiC. Based on the Rice criterion of ductility, the results predict that Mg, Fe, and Ti are promising candidates for improving the ductility of Al/TiC interfaces. (paper)

Adsorption of arsenate on Cu/Mg/Fe/La layered double hydroxide from aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Guo, Yanwei [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Zhu, Zhiliang, E-mail: zzl@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Qiu, Yanling [Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Zhao, Jianfu [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

2012-11-15

Highlights: Black-Right-Pointing-Pointer A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized. Black-Right-Pointing-Pointer The average pore size of the materials with about 16 nm indicated that the mesoporous structures existed in the Cu/Mg/Fe/La-LDHs. Black-Right-Pointing-Pointer The adsorption capacity of As(V) increased with the increment of La{sup 3+} content in the LDH. Black-Right-Pointing-Pointer The maximum adsorption capacity of the synthesized Cu/Mg/Fe/La-LDH for arsenate was 43.5 mg/g. - Abstract: A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized and used for the removal of arsenate from aqueous solutions. The purpose of incorporation of La{sup 3+} into LDHs was tried to enhance the uptake efficiency of arsenate and broaden the application field of LDHs functional materials. Effects of various physico-chemical factors such as solution pH, adsorbent dosage, contact time and initial arsenate concentrations on the adsorption of arsenate onto Cu/Mg/Fe/La-LDH were investigated. Results showed that the removal efficiency of arsenate increased with the increment of the lanthanum content in Cu/Mg/Fe/La-LDH adsorbents, and the optimized lanthanum content was 20% of the total trivalent metals composition (Fe{sup 3+} and La{sup 3+}). The adsorption isotherms can be well described by Langmuir equation, and the adsorption kinetics of arsenate followed the pseudo-second-order kinetic model. Coexistent ions such as HPO{sub 4}{sup 2-}, CO{sub 3}{sup 2-}, SO{sub 4}{sup 2-}, Cl{sup -} and NO{sub 3}{sup -} exhibited obvious competition with arsenate for the adsorption on Cu/Mg/Fe/La-LDH. The solution pH significantly affected the removal efficiency, which was closely related to the change of arsenate species distribution under different pH conditions. The predominant adsorption mechanism can be mainly attributed to the processes including ion exchange and layer ligand exchange.

Adsorption of arsenate on Cu/Mg/Fe/La layered double hydroxide from aqueous solutions

International Nuclear Information System (INIS)

Guo, Yanwei; Zhu, Zhiliang; Qiu, Yanling; Zhao, Jianfu

2012-01-01

Highlights: ► A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized. ► The average pore size of the materials with about 16 nm indicated that the mesoporous structures existed in the Cu/Mg/Fe/La-LDHs. ► The adsorption capacity of As(V) increased with the increment of La 3+ content in the LDH. ► The maximum adsorption capacity of the synthesized Cu/Mg/Fe/La-LDH for arsenate was 43.5 mg/g. - Abstract: A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized and used for the removal of arsenate from aqueous solutions. The purpose of incorporation of La 3+ into LDHs was tried to enhance the uptake efficiency of arsenate and broaden the application field of LDHs functional materials. Effects of various physico-chemical factors such as solution pH, adsorbent dosage, contact time and initial arsenate concentrations on the adsorption of arsenate onto Cu/Mg/Fe/La-LDH were investigated. Results showed that the removal efficiency of arsenate increased with the increment of the lanthanum content in Cu/Mg/Fe/La-LDH adsorbents, and the optimized lanthanum content was 20% of the total trivalent metals composition (Fe 3+ and La 3+ ). The adsorption isotherms can be well described by Langmuir equation, and the adsorption kinetics of arsenate followed the pseudo-second-order kinetic model. Coexistent ions such as HPO 4 2− , CO 3 2− , SO 4 2− , Cl − and NO 3 − exhibited obvious competition with arsenate for the adsorption on Cu/Mg/Fe/La-LDH. The solution pH significantly affected the removal efficiency, which was closely related to the change of arsenate species distribution under different pH conditions. The predominant adsorption mechanism can be mainly attributed to the processes including ion exchange and layer ligand exchange.

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 ...

Nanostructured Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode for efficient hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Sharma, Dipika; Upadhyay, Sumant; Verma, Anuradha [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Satsangi, Vibha R. [Department of Physics Computer Sciences, Dayalbagh Educational Institute, Agra-282 110 India (India); Shrivastav, Rohit [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Dass, Sahab, E-mail: drsahabdas@gmail.com [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India)

2015-01-01

Nanostructured thin films of pristine Fe{sub 2}O{sub 3}, Ti-doped Fe{sub 2}O{sub 3}, Cu{sub 2}O, and Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-doped Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction were deposited on tin-doped indium oxide (Sn:In{sub 2}O{sub 3}) glass substrate using spray pyrolysis method. Ti doping is done to improve photoelectric conversion efficiency and electrical conductivity of hematite thin films. Further enhanced photocurrent is achieved for Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction electrodes. All samples were characterized using X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and UV-Vis spectrometry. Photoelectrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pristine Fe{sub 2}O{sub 3}, Ti-Fe{sub 2}O{sub 3}, Cu{sub 2}O, Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction thin films exhibited absorption in visible region. Nanostructured thin films as prepared were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 2.60 mA/cm{sup 2} at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode. Increased photocurrent density and enhanced incident photon-to-electron conversion efficiency, offered by the heterojunction thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O interface. - Highlights: • Heterojunction thin films were deposited using spray pyrolysis techniques. • Titanium doping in Fe{sub 2}O{sub 3} played a significant role in PEC response. • Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction shows the absorption in visible range. • Improved charge separation and enhanced PEC response were achieved in Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O.

Photoelectrochemical Properties of CuO Grown by Using a Modified Chemical Bath Deposition Method

Energy Technology Data Exchange (ETDEWEB)

Ha, Jin-wook; Ryu, Hyukhyun [Inje University, Gimhae (Korea, Republic of); Lee, Won-Jae [Dong-Eui University, Busan (Korea, Republic of)

2016-06-15

In this study, cupric oxide (CuO) nanorods were grown on the fluorine-doped tin oxide (FTO) glass substrate using a modified-chemical bath deposition (M-CBD) method. We investigated the morphology, structural, optical and photoelectrochemical properties of the cupric oxide nanorods with various growth durations by using field-emission scanning-electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectroscopy (UV-vis) and three-electrode potentiostat, respectively. In this work, we found that the morphologies, thickness, growth rate, crystallinities, grain sizes and optical bandgap were controllable on the growth duration, which affected photocurrent density and photo-stability. The highest growth rate of CuO nanorods was 126 nm/min. From the XRD measurement, we also confirmed that (020) directional growth affected the growth of the CuO nanorods. A maximum photocurrent density of-1.88 mA/cm² at -0.55 V (vs. SCE) and high photo-stability value about 40% was obtained with 10 minutes growth duration.

Influences of annealing temperature on sprayed CuFeO2 thin films

Science.gov (United States)

Abdelwahab, H. M.; Ratep, A.; Abo Elsoud, A. M.; Boshta, M.; Osman, M. B. S.

2018-06-01

Delafossite CuFeO2 thin films were successfully prepared onto quartz substrates using simple spray pyrolysis technique. Post annealing under nitrogen atmosphere for 2 h was necessary to form delafossite CuFeO2 phase. The effect of alteration in annealing temperature (TA) 800, 850 and 900 °C was study on structural, morphology and optical properties. The XRD results for thin film annealed at TA = 850 °C show single phase CuFeO2 with rhombohedral crystal system and R 3 bar m space group with preferred orientation along (0 1 2). The prepared copper iron oxide thin films have an optical transmission ranged ∼40% in the visible region. The optical direct optical band gap of the prepared thin films was ranged ∼2.9 eV.

Cu (II) binded chitosan/Fe3O4 nanocomomposite as a new biosorbent for efficient and selective removal of phosphate.

Science.gov (United States)

Zavareh, Siamak; Behrouzi, Zahra; Avanes, Armen

2017-08-01

The aim of this study was to develop a chitosan-based magnetic adsorbent for selective and effective removal of phosphate from aqueous solutions. For this purpose, Cu-chitosan/Fe 3 O 4 nanocomposite was prepared using a facile method and characterized. The prepared adsorbent exhibited more porous surface with higher specific area compared to neat chitosan based on SEM and BET studies. The FTIR and EDX studies indicated the presence of Cu(II) bonded to the adsorbent surface. Crystalline properties of the adsorbent were also studied using XRD. Experimental isotherm data were fitted to nonlinear forms of Langmuir and Freunlich models. The maximum capacity for the modified adsorbent was calculated to be 88mg P 2 O 5 /g, much higher than that for neat chitosan and chitosan/Fe 3 O 4 according to the Langmuir isotherm. The adsorption by the modified adsorbent had fast kinetics and obeyed pseudo-second-order kinetic model. Interestingly, the maximum removal efficiency for the modified adsorbent was observed in neutral pH values, pHs of natural waters. A high selectivity against natural waters common anions as well as good regeneration ability was obtained for the introduced adsorbent. Copyright © 2017 Elsevier B.V. All rights reserved.

Microwave-Assisted Synthesis of CuFe2O4 Nanoparticles and Starch-Based Magnetic Nanocomposites

Directory of Open Access Journals (Sweden)

Gh. Nabiyouni

2013-06-01

Full Text Available Magnetic CuFe2O4 nanoparticles were synthesized by a facile microwave-assisted reaction between Cu(NO32 and Fe(NO33. The magnetic nanoparticles were added to starch to make magnetic polymeric nanocomposite. The nanoparticles and nanocomposites were characterized using X-ray diffraction and scanning electron microscopy. The magnetic properties of the samples were investigated using an alternating gradient force magnetometer (AGFM. The copper ferrite nanoparticles exhibited ferromagnetic behavior at room temperature, with a saturation magnetization of 29emu/g and a coercivity of 136 Oe. The distribution of the CuFe2O4 nanoparticles into the polymeric matrixes decreases the coercivity (136 Oe to 66 Oe. The maximum coercivity of 82 Oe was found for 15% of CuFe2O4 distributed to the starch matrix.

Adsorption performance of CuFe{sub 2}O{sub 4}/rGO nanocomposites towards organic dye

Energy Technology Data Exchange (ETDEWEB)

Tang, Mingyi, E-mail: mingyitjucu@163.com [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Li, Xichuan [School of Science, Tianjin University, Tianjin 300072 (China); Gao, Chunjuan [State Ocean Adm, Inst Tianjin Seawater Desalinat & Multipurpose Ut, Tianjin 300192 (China); Li, Xianxian [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia, E-mail: haixiaqiuls@163.com [School of Science, Tianjin University, Tianjin 300072 (China)

2017-01-01

A facile and efficient approach was employed to synthesize CuFe{sub 2}O{sub 4}/rGO (reduced graphene oxide) nanocomposites. The morphology, crystal structure and properties of the prepared CuFe{sub 2}O{sub 4}/rGO nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction and thermo-gravimetric analysis. The CuFe{sub 2}O{sub 4}/rGO nanocomposites were applied as adsorbents to study their adsorption performance for Congo red. The adsorption capacity and recyclability, adsorption dynamics and adsorption models were investigated. The results show that the CuFe{sub 2}O{sub 4}/rGO nanocomposites are efficient and recyclable adsorbents. - Highlights: • CuFe{sub 2}O{sub 4}/rGO was synthesized by a facile hydrothermal route. • As an adsorbent it showed high adsorption capacity to CR. • It was magnetically removable and has high reusability.

Magnetic and structural properties of Cu{sub 0.85}Fe{sub 0.15}O system synthesized by co-precipitation

Energy Technology Data Exchange (ETDEWEB)

Colorado, H. D., E-mail: herdacom@gmail.com; Perez Alcazar, G. A. [Universidad del Valle, Departamento de Fisica (Colombia)

2011-11-15

Cu{sub 0.94}Fe{sub 0.06}O and Cu{sub 0.85}Fe{sub 0.15}O samples were synthesized by using the co-precipitation chemical method. Starting from aqueous solutions of copper nitrate, CuO (NO{sub 3}){sub 2} 3H{sub 2}O, iron nitrate, Fe (NO{sub 3}){sub 3} 9H{sub 2}O and sodium hydroxide as precipitating agent, NaOH. The precipitate of three samples for Cu{sub 0.94}Fe{sub 0.06}O and five for Cu{sub 0.85}Fe{sub 0.15}O of fine powder were calcined for 5 h at different temperatures. The obtained X rays diffraction patterns refined by the Rietveld method show the CuO characteristic pattern, showing that the Fe atoms enter to replace Cu atoms. Furthermore, it was obtained that the crystallite size decreases with calcination temperatures for Cu{sub 0.94}Fe{sub 0.06}O. The transmission Moessbauer spectroscopy showed that the samples present a disordered paramagnetic behavior due to the big value of the half-width of line of the quadrupolar splitting. Vibrating sample magnetometry confirms the paramagnetic character. The XRD results indicate that the material is nanostructured, due that the crystallite sizes are of the order of 10 nm for Cu{sub 0.94}Fe{sub 0.06}O and 40 nm for Cu{sub 0.85}Fe{sub 0.15}O.

Thermodynamic properties of Al-Mn, Al-Cu, and Al-Fe-Cu melts and their relations to liquid and quasicrystal structure

International Nuclear Information System (INIS)

Zaitsev, A I; Zaitseva, N E; Shimko, R Yu; Arutyunyan, N A; Dunaev, S F; Kraposhin, V S; Lam, Ha Thanh

2008-01-01

Thermodynamic properties of molten Al-Mn, Al-Cu and Al-Fe-Cu alloys in a wide temperature range of 1123-1878 K and the whole range of concentrations have been studied using the integral effusion method and Knudsen mass spectrometry. Thermodynamic functions of melts were described by the associated solution model. The possibility of icosahedral quasicrystal (i-QC) precipitation from liquid Al-Mn and Al-Cu-Fe alloys was found to be a consequence of the existence in liquid associates (clusters). A geometric model is suggested for the structure of associates in liquid

Design and characterization of FeCrNiCoAlCu and FeCrNiCo(AlCu){sub 0,5} multicomponent alloys; Previsao e caracterizacao de ligas multicomponentes FeCrNiCoAlCu e FeCrNiCo(AlCu){sub 0,5}

Energy Technology Data Exchange (ETDEWEB)

Triveno Rios, Carlos; Artacho, Victor Falcao [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Engenharia de Materiais

2014-07-01

High entropy alloys using multi-element main quasi-equivalent atomic proportions and generally forms single-phase solid solution and has the ability to enhance levels of strain hardening combined with high levels of plastic deformation at room temperature. In this work two high-entropy alloys with almost similar composition were studied and the factors influencing the formation of solid solution phases (δ atomic radius difference, ΔH{sub mix} mixing enthalpy, ΔS{sub mix} mixing entropy) were evaluated. The microstructure as-cast and the compositions of phases in the two alloys were analyzed by SEM and XRD. The mechanical characterization was realized by measurements of microhardness and cold compression test. The results showed that FeCrNiCo(AlCu){sub 0,5} and FeCrNiCoAlCu alloys with δ equal to 5,7 and 4,9, respectively, form alloys with solid solutions of high entropy. However, the presence of FC and BCCC structures greatly influence the mechanical properties. (author)

A facile approach to fabricate of photothermal functional Fe{sub 3}O{sub 4}@CuS microspheres

Energy Technology Data Exchange (ETDEWEB)

Zhang, Baolong; Shan, Yan, E-mail: shanyan@qust.edu.cn; Chen, Kezheng, E-mail: kchen@qust.edu.cn

2017-06-01

Photothermal functional Fe{sub 3}O{sub 4}@CuS microspheres have been prepared successfully by a simple chemical deposition method. The adsorption of cetyltrimethyl-ammonium bromide (CTAB) on the magnetic microspheres plays an important role in forming the structure of the composites. The present materials are characterized with XRD, TEM, SEM, FTIR, and UV-VIS-NIR spectrophotometer. The results show that Fe{sub 3}O{sub 4} microspheres are coated by CuS layer with thickness of 10 nm. The saturation magnetization value of Fe{sub 3}O{sub 4}@CuS core-shell microspheres is 27 emu/g at room temperature and the sample possesses excellent magnetic response in the presence of applied magnetic field. Moreover, these microspheres exhibit good dispersion, suitable size and significant photothermal conversion efficiency up to 20.7% at 808 nm laser irradiation. Fluctuation value of the highest temperature of Fe{sub 3}O{sub 4}@CuS dispersion over four times LASER ON/OFF indicates that photothermal stability of Fe{sub 3}O{sub 4}@CuS microspheres is good. - Highlights: • The Fe{sub 3}O{sub 4} microspheres have been coated with CuS and the thickness of CuS layer is about 10 nm. • The Fe{sub 3}O{sub 4}@CuS microspheres are ferromagnetism, and possess good photothermal conversion efficiency and photostability. • The materials have great potential application for photothermal therapy.

Hierarchical structured Sm2O3 modified CuO nanoflowers as electrode materials for high performance supercapacitors

Science.gov (United States)

Zhang, Xiaojuan; He, Mingqian; He, Ping; Liu, Hongtao; Bai, Hongmei; Chen, Jingchao; He, Shaoying; Zhang, Xingquan; Dong, Faqing; Chen, Yang

2017-12-01

By a simple and cost effective chemical precipitation-hydrothermal method, novel hierarchical structured Sm2O3 modified CuO nanoflowers are prepared and investigated as electrode materials for supercapacitors. The physical properties of prepared materials are characterized by XRD, FE-SEM, EDX and FTIR techniques. Furthermore, electrochemical performances of prepared materials are investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrum in 1.0 M KOH electrolyte. The resulting Sm2O3 modified CuO based electrodes exhibit obviously enhanced capacitive properties owing to the unique nanostructures and strong synergistic effects. It is worth noting that the optimized SC-3 based electrode exhibits the best electrochemical performances in all prepared electrodes, including higher specific capacitance (383.4 F g-1 at 0.5 A g-1) and good rate capability (393.2 F g-1 and 246.3 F g-1 at 0.3 A g-1 and 3.0 A g-1, respectively), as well as excellent cycling stability (84.6% capacitance retention after 2000 cycles at 1.0 A g-1). The present results show that Sm2O3 is used as a promising modifier to change the morphology and improve electrochemical performances of CuO materials.

Note: Resonance magnetoelectric interactions in laminate of FeCuNbSiB and multilayer piezoelectric stack for magnetic sensor

Science.gov (United States)

Li, Jianqiang; Lu, Caijiang; Xu, Changbao; Zhong, Ming

2015-09-01

This paper develops a simple miniature magnetoelectric (ME) laminate FeCuNbSiB/PZT-stack made up of magnetostrictive Fe73.5Cu1Nb3Si13.5B9 (FeCuNbSiB) foils and piezoelectric Pb(Zr, Ti)O3 (PZT) multilayer stack vibrator. Resonant ME interactions of FeCuNbSiB/PZT-stack with different layers of FeCuNbSiB foil (L) are investigated in detail. The experimental results show that the ME voltage coefficient reaches maximum value of 141.5 (V/cm Oe) for FeCuNbSiB/PZT-stack with L = 6. The AC-magnetic sensitivities can reach 524.29 mV/Oe and 1.8 mV/Oe under resonance 91.6 kHz and off-resonance 1 kHz, respectively. The FeCuNbSiB/PZT-stack can distinguish small dc-magnetic field of ˜9 nT. The results indicate that the proposed ME composites are very promising for the cheap room-temperature magnetic field sensing technology.

Eutectic Al-Si-Cu-Fe-Mn alloys with enhanced mechanical properties at room and elevated temperature

International Nuclear Information System (INIS)

Wang, E.R.; Hui, X.D.; Chen, G.L.

2011-01-01

Highlights: → Fabricated a kind of high performance Al-Si alloy with low production costs. → Clarified two different morphologies of α-Fe and corresponding crystal structures. → Analyzed the crystallography of Cu-rich phases before and after T6 treatment. → Fracture mechanism of precipitates in experimental alloys during tensile process. -- Abstract: In this paper, we report a novel kind of eutectic Al-Si-Cu-Fe-Mn alloy with ultimate tensile strength up to 336 MPa and 144.3 MPa at room temperature and 300 o C, respectively. This kind of alloy was prepared by metal mold casting followed by T6 treatment. The microstructure is composed of eutectic and primary Si, α-Fe, Al 2 Cu and α-Al phases. Iron-rich phases, which were identified as BCC type of α-Fe (Al 15 (Fe,Mn) 3 Si 2 ), exist in blocky and dendrite forms. Tiny blocky Al 2 Cu crystals disperse in α-Fe dendrites or at the grain boundaries of α-Al. During T6 treatment, Cu atoms aggregate from the super-saturation solid solution to form GP zones, θ'' or θ'. Further analysis found that the enhanced mechanical properties of the experimental alloy are mainly attributed to the formation of α-Fe and copper-rich phases.

Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

International Nuclear Information System (INIS)

Rajabi, S.K.; Sohrabnezhad, Sh.; Ghafourian, S.

2016-01-01

Magnetic Fe 3 O 4 @CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe 3 O 4 @HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe 3 O 4 core and a CuO shell. The Fe 3 O 4 @CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe 3 O 4 -CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent. - Graphical abstract: Fe 3 O 4 @CuO core-shell release of copper ions. These Cu 2+ ions were responsible for the exhibited antibacterial activity. - Highlights: • The Fe 3 O 4 @CuO core-shell was prepared by MOF method. • This is the first study of antibacterial activity of core-shell consist of CuO and Fe 3 O 4 . • The core-shell can be reused effectively. • Core-shell was separated from the reaction solution by external magnetic field.

Determination of Fe, Cu and Zn in sugar-cane spirits commercialized in Southeastern Brazil by TXRF

International Nuclear Information System (INIS)

Cunha e Silva, R.M.; Almeida, E.; Valencia, E.P.E.; Nascimento Filho, V.F.

2004-01-01

Total reflection X-ray fluorescence (TXRF) was used to determine simultaneously the concentration of Cu, Fe and Zn in seven sugar-cane spirit samples ('aguardente'), a processed alcoholic beverage made from the fermentation and distillation of sugar-cane juice. The limits of detection ranged from 35 to 8 ng x ml -1 for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Se. Excluding Fe, Cu and Zn, the concentrations were below their limits. Two samples showed Cu concentrations higher than the value allowed by Brazilian legislation (5 μg x ml -1 ), and concerning Fe and Zn, no sample were above the limits permitted by WHO for drinking water (2 and 3 μg x ml -1 , respectively). (author)

MAGNETIC AND HYPERFINE CHARACTERIZATION OF THE THERMAL TRANSFORMATION CuO - Fe2O3 TO Fe3O4

Directory of Open Access Journals (Sweden)

Juan D. Betancur

2018-01-01

Full Text Available A magnetic study about the thermal transformation of hematite doped with CuO (Fe2O3 + CuO is presented. The heat treatment was carried out at a temperature of 375 ± 1 ºC, in a controlled atmosphere composed by 20% hydrogen and 80% nitrogen. Samples were characterized by Mössbauer spectroscopy at room temperature, magnetization as a function of temperature and hysteresis loops at 10K. Our results suggest that both the hyperfine fields and linewidths of the A and B sites remain essentially constant with increasing the CuO concentration, while at the same time a paramagnetic component arises, which is indicative of the appearance of a precipitate or a new phase of Fe-Cu, i.e. there is not an effective incorporation of the copper into the structure of the magnetite. The saturation magnetization falls from approximately 87 emu/g to 78 emu/g, consistent with such a paramagnetic phase. Also, an increase in the coercivity from ~576 Oe up to ~621 Oe by increasing the percentage of CuO from 2% up to 20% is observed. Such increase is also attributed to the paramagnetic phase acting as pinning center for domain walls, besides also de pinning effect due to vacancies induced by the thermal treatment. Finally, an inversion of the magnetization in the Verwey temperature is observed. The data suggest that by means of the synthesis method employed, it is possible to obtain Fe3O4 magnetite particles coexisting with precipitates of Fe-Cu, giving rise to a modification in the magnetic properties and generatingan interesting effect in the magnetization at the Verwey temperature.

Modulation of Jahn-Teller effect on magnetization and spontaneous electric polarization of CuFeO2

Science.gov (United States)

Xiao, Guiling; Xia, Zhengcai; Wei, Meng; Huang, Sha; Shi, Liran; Zhang, Xiaoxing; Wu, Huan; Yang, Feng; Song, Yujie; Ouyang, Zhongwen

2018-03-01

CuFe0.99Mn0.01O2 and CuFe0.99Co0.01O2 single crystal samples are grown by a floating zone technique and their magnetization and spontaneous electric polarization have been investigated. Similarly with pure CuFeO2, an obviously anisotropic magnetization and spontaneous electric polarization were observed in the both doped samples, and their phase transition critical fields and temperatures are directly doping ion dependent. Considering the different d-shell configuration and ionic size between Mn3+, Co3+ and Fe3+ ions, in which the Mn3+ ion with Jahn-Teller (J-T) effect has different distortion on the geometry frustration from both of Fe3+ and Co3+ ion. Since for Mn3+ ion, the orbital splitting results from the low-symmetry J-T distortion in a crystal-field environment leads to a distorted MnO6 octahedron, which different from undistorted FeO6 and CoO6 octahedrons. The strain between distorted and undistorted octahedrons produces different effects on the spin reorientation transition and spontaneous electric polarization. Although the pure CuFeO2 has a very strong and robust frustration, the presence of the strain due to the random distribution of distorted MnO6 octahedron and undistorted CoO6 (FeO6) octahedrons leads to its spin reorientation transitions and spontaneous electric polarization different from CuFeO2.

Charge compensation and magnetic properties in Sr and Cu doped La-Fe perovskites

Directory of Open Access Journals (Sweden)

de Julián Fernández C.

2013-01-01

Full Text Available Orthorhombic lanthanum orthoferrites La0.8Sr0.2Fe1-yCuyO3-w (y = 0 and 0.10 have been studied using X-rays and neutron powder diffraction (XRPD and NPD, magnetization measurements and 57Fe Mössbauer spectroscopy. Rietveld refinements on XRPD and NPD data show that they adopt an orthorhombic ABO3 perovskite symmetry with La/Sr and Fe/Cu atoms randomly distributed on crystal A and B sites, respectively. The magnetic structure at room temperature is antiferromagnetic, with the Fe/Cu magnetic moments aligned along the a axis. Magnetization curves versus temperature show that the compounds exhibit an overall antiferromagnetic and a weak ferromagnetic behaviour in the range 5-298 K. 57Fe Mössbauer spectroscopy measurements indicate that Fe3+ and Fe5+ ions coexist in both compounds, and the relative percentage of Fe5+ is almost the same at 77 and 170 K, rejecting a charge disproportion mechanism.

Magnetoimpedance effect of the Ni80Fe20/Cu composite wires: The influence of DC current imposed on the Cu base

Directory of Open Access Journals (Sweden)

Delu Chen

2014-06-01

Full Text Available In this paper, the copper composite wires of 75 μm in diameter with a sputtered layer of Ni80Fe20 permalloy were prepared, with a DC current applied to the basal Cu terminals during the fabrication process. The influence of the DC current on the magnetic configuration and Magneto-Impedance (MI effect was studied. The results indicate that both the current amplitude and actuation duration have significant effect on the magnetic properties of the Ni80Fe20 layer. With appropriate current applied, the induced magnetic field leads to a circumferential magnetic domain structure and reduces significantly the equivalent anisotropy field of Ni80Fe20 layer. Then, the GMI ratio of the composite wires was significantly increased. A maximum GMI of 194.8% can be reached when the current was fixed at 100 mA and the Ni80Fe20 thickness is 780 nm. If the Ni80Fe20 thickness is above 780 nm, the coercivity of the coating layer increases while the GMI ratio of the composite wire reduces, since the magnetic anisotropy of the Ni80Fe20 layer varies from circumferential to longitudinal. The results were explained combining the thermal and magnetic effects of current.

Responses of mixed methanotrophic consortia to variable Cu2+/Fe2+ ratios.

Science.gov (United States)

Chidambarampadmavathy, Karthigeyan; Karthikeyan, Obulisamy Parthiba; Huerlimann, Roger; Maes, Gregory E; Heimann, Kirsten

2017-07-15

Methane mitigation in landfill top cover soils is mediated by methanotrophs whose optimal methane (CH 4 ) oxidation capacity is governed by environmental and complex microbial community interactions. Optimization of CH 4 remediating bio-filters need to take microbial responses into account. Divalent copper (Cu 2+ ) and iron (Fe 2+ ) are present in landfills at variable ratios and play a vital role in methane oxidation capacity and growth of methanotrophs. This study, as a first of its kind, therefore quantified effects of variable Cu 2+ and Fe 2+ (5:5, 5:25 and 5:50 μM) ratios on mixed methanotrophic communities enriched from landfill top cover (LB) and compost soils (CB). CH 4 oxidation capacity, CH 4 removal efficiencies, fatty acids content/profiles and polyhydroxybutyrate (PHB; a biopolymer) contents were also analysed to quantify performance and potential co-product development. Mixed methanotroph cultures were raised in 10 L continuous stirred tank reactors (CSTRs, Bioflo ® & Celligen ® 310 Fermentor/Bioreactor; John Morris Scientific, Chatswood, NSW, Australia). Community structure was determined by amplifying the V3-V4 region of 16s rRNA gene. Community structure and, consequently, fatty acid-profiles changed significantly with increasing Cu 2+ /Fe 2+ ratios, and responses were different for LB and CB. Effects on methane oxidation capacities and PHB content were similar in the LB- and CB-CSTR, decreasing with increasing Cu 2+ /Fe 2+ ratios, while biomass growth was unaffected. In general, high Fe 2+ concentration favored growth of the type -II methanotroph Methylosinus in the CB-CSTR, but methanotroph abundances decreased in the LB-CSTR. Increase in Cu 2+ /Fe 2+ ratio increased the growth of Sphingopyxis in both systems, while Azospirllum was co-dominant in the LB- but absent in the CB-CSTR. After 13 days, methane oxidation capacities and PHB content decreased by ∼50% and more in response to increasing Fe 2+ concentrations. Although methanotroph

Partitioning of Cu between mafic minerals, Fe-Ti oxides and intermediate to felsic melts

Science.gov (United States)

Liu, Xingcheng; Xiong, Xiaolin; Audétat, Andreas; Li, Yuan

2015-02-01

This study used improved capsule technique i.e., Pt95Cu05 or Au95Cu05 alloy capsules as Cu sources to determine Cu partitioning between mafic minerals, Fe-Ti oxides and intermediate to felsic melts at 0.5-2.5 GPa, 950-1100 °C and various oxygen fugacities (fO2). In combination with the data from the mafic composition systems, the results demonstrate that Cu is generally highly incompatible in mafic minerals and moderately incompatible to compatible in Fe-Ti oxides. The general order of mineral/melt Cu partition coefficients (DCu) is garnet (0.01-0.06) ⩽ olivine (0.04-0.20) ≈ opx (0.04-0.24) ≈ amphibole (0.04-0.20) ⩽ cpx (0.04-0.45) ⩽ magnetite, titanomagnetite and Cr-spinel (0.18-1.83). The variations in DCu depend mainly on temperature, fO2 or mineral composition. In general, DCu for olivine (and perhaps opx) increases with decreasing temperature and increasing fO2. DCu increases for cpx with Na+ (pfu) in cpx, for magnetite and Cr-spinel with Fe3+ (pfu) in these phases and for titanomagnetite with Ti4+ (pfu) in this phase. The large number of DCu data (99 pairs) serves as a foundation for quantitatively understanding the behavior of Cu during magmatic processes. The generation of intermediate to felsic magmas via fractional crystallization or partial melting of mafic rocks (magmas) at deep levels of crust involves removal of or leaving assemblages of mafic minerals + Fe-Ti oxides ± sulfides. With our DCu data on mafic minerals and Fe-Ti oxides, DCubulk values around 0.2 were obtained for the sulfide-free assemblages. Cu will thus be concentrated efficiently in the derived melts during these two processes if sulfides are absent or negligible, explaining that high fO2 and sulfide-destabilization are favorable to formation of the porphyry Cu system.

Giant magnetoresistance effect in CoZr/Cu/Co spin-valve films (abstract)

Energy Technology Data Exchange (ETDEWEB)

Ben-Youssef, J. [CNRS-LMIMS, 92195 Meudon-Bellevue (France)]|[LPM Universite Mohammed V, Rabat (Morocco); Koshkina, O.; Le Gall, H. [CNRS-LMIMS, 92195 Meudon-Bellevue (France); Harfaoui, M.E. [LPMC Universite Ibn Tofail Kenitra (Morocco); Bouziane, K. [CNRS-LMIMS, 92195 Meudon-Bellevue (France); Yamani, M.E. [LPM Universite Mohammed V, Rabat (Morocco); Desvignes, J.M. [CNRS-LMIMS, 92195 Meudon-Bellevue (France)

1997-04-01

A high sensitivity of giant magnetoresistance (GMR) has been observed recently from soft magnetic layers such as NiFe, NiFeCo, and FeCoB. Amorphous CoZr alloys present ultrasoft properties compared to NiFe. GMR has been investigated for amorphous CoZr/Cu/Co thin films grown by rf diode sputtering using a target consisting of a Co disk partially covered with a Zr foil. The influence of the argon pressure on Cu layer deposition, Cu thickness, and Zr content on magnetic and transport properties was analyzed. The highest value of transverse GMR obtained along the easy axis is 3.6{percent} and the MR curve was saturated in a magnetic field of 100 Oe at room temperature. GMR shows scaling behavior with the sample composition. Very high sensitivity, around 1{endash}2{percent}/Oe was observed in a CoZr (3 nm)/Cu (3 nm)/Co (2 nm) sandwich. This study shows a large dependence of GMR on Cu thickness and the maximum of magnetoresistance strongly depending on the Ar pressure which modifies the interface roughness. The Zr content also influences the magnetotransport properties ({Delta}R/R and {Delta}R/R{Delta}H). The difference in coercivity between soft magnetic CoZr and hard magnetic Co layers induces antiferromagnetic alignment. Therefore a high MR ratio and field sensitivity are achieved by improving the magnetic properties of the CoZr layer.{copyright} {ital 1997 American Institute of Physics.}

Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

Science.gov (United States)

Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

2013-10-01

A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

Study of defect annealing behaviour in neutron irradiated Cu and Fe using positron annihilation and electrical conductivity

International Nuclear Information System (INIS)

Eldrup, M.; Singh, B.N.

2000-01-01

To compare the defect accumulation and the annealing behaviour in an fcc and a bcc metal, OFHC-Cu and pure Fe were neutron irradiated at 100 deg. C to a fluence of 1.5 x 10 24 n/m 2 , (E > 1 MeV). Isochronal annealing was carried out and the annealing behaviour followed by positron annihilation spectroscopy (PAS) as well as electrical conductivity measurements. The results for the two specimens in the as-irradiated state are very different. In Cu the defect positron lifetime is characteristic of single vacancies, very small vacancy clusters or stacking fault tetrahedra, while in Fe the defect lifetimes confirm the presence of micro-voids and voids. The electrical conductivity, on the other hand does not discriminate between the two types of damage in the irradiated specimens. During annealing of the irradiated Fe below stage V, the average void size grows by migration and coalescence of the micro-voids and voids. At and above stage V the void density decreases and the voids finally anneal out at ∼500 deg. C. In contrast, the annealing of irradiated Cu below stage V does not yield any evidence for the evolution of micro-voids or voids. The implications of these results are discussed. One conclusion is that neutron irradiation below stage V causes higher void swelling in bcc iron than in fcc copper

Nanocrystalline (Fe{sub 60}Al{sub 40}){sub 80}Cu{sub 20} alloy prepared by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Krifa, M.; Mhadhbi, M. [Laboratoire de Chimie Inorganique, 99/UR/12-22, FSS – Université de Sfax, B.P. 1171, Sfax 3018 (Tunisia); Escoda, L.; Güell, J.M. [Dept. de Fisica, Universitat de Girona, Campus Montilivi, 17071 Girona (Spain); Suñol, J.J., E-mail: joanjosep.sunyol@udg.edu [Dept. de Fisica, Universitat de Girona, Campus Montilivi, 17071 Girona (Spain); Llorca-Isern, N.; Artieda-Guzmán, C. [Dept. CMEM, Universitat de Barcelona, Martí Franques 1, 08028 Barcelona (Spain); Khitouni, M. [Laboratoire de Chimie Inorganique, 99/UR/12-22, FSS – Université de Sfax, B.P. 1171, Sfax 3018 (Tunisia)

2013-03-25

Highlights: ► Nanocrystalline Fe(Al, Cu) powdered alloy (10 nm) has been synthesized by MA. ► Decreasing the crystallite size increases coercivity and squareness ratio. ► As low crystallites size stronger hard ferromagnetic material results. -- Abstract: A nanostructured disordered Fe(Al, Cu) solid solution was obtained from prealloyed FeAl and elemental Cu powders using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. The transformation of the phase depends upon the milling time. With the increase of milling time all Cu atoms became dissolved in the bcc Fe and the final product of the MA process was the nanocrystalline Fe(Al, Cu) solid solution with a mean crystallite size of 10 nm. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Magnetic properties were also investigated and were related to the microstructural changes. The system showed hard magnetic behavior.

Nucleation and growth of a BCC Fe phase deposited on a single crystal (001) Cu film

International Nuclear Information System (INIS)

Koike, J.

1991-01-01

As a thin film overlayer grows on a substrate with a different structure, the overlayer initially adopts the substrate structure and subsequently transforms to an equilibrium bulk structure. such a growth characteristic has been extensively studied in Fe/Cu bicrystals. An Fe overlayer grown on a Cu substrate is known to have the fcc structure up to a thickness of 2 nm, whereas a thicker Fe overlayer consists of submicrometer grains of the bcc-Cu has been reported in a relatively thick Fe film and was found to consist of the Nishiyama (N), Kurdjumov-Sacks (KS), or Pitsch (P), depending on the orientation of the substrate surface. However, previous studies have not explained how the bcc structure nucleates or how the observed submicrometer polycrystalline grains form. The paper provides an understanding of these two points. Transmission electron microscopy (TEM) was used to study Fe/Cu bicrystals as the Fe thickness was varied systematically. Analysis of moire fringes, which are caused by superposition of different structures, enabled us to determine the orientation relationship between the very thin Fe layer and the Cu substrate. We show that a single variant of the P orientation relationship, which accompanies atomic rearrangement parallel to the interface, predominates at the nucleation stage of the bcc structure. Nucleation of other variants of P, N, and KS occurs with increasing Fe thickness and causes the formation of the submicrometer bcc grains

Microstructure and Electrical Properties of Fe,Cu Substituted (Co,Mn)3O4 Thin Films

DEFF Research Database (Denmark)

Szymczewska, Dagmara; Molin, Sebastian; Hendriksen, Peter Vang

2017-01-01

In this work, thin films (~1000 nm) of a pure MnCo2O4 spinel together with its partially substituted derivatives (MnCo1.6Cu0.2Fe0.2O4, MnCo1.6Cu0.4O4, MnCo1.6Fe0.4O4) were prepared by spray pyrolysis and were evaluated for electrical conductivity. Doping by Cu increases the electrical conductivit...

Effects of interfacial transition layers on the electrical properties of individual Fe 30 Co 61 Cu 9 /Cu multilayer nanowires

KAUST Repository

Ma, Hongbin

2016-01-01

In this work, we accurately measure the electrical properties of individual Fe30Co61Cu9/Cu multilayered nanowires using nanomanipulators in in situ scanning electron microscopy to reveal that interfacial transition layers are influential in determining their transport behaviors. We investigate the morphology, crystal structure and chemistry of the Fe30Co61Cu9/Cu multilayered nanowires to characterize them at the nanoscale. We also compare the transport properties of these multilayered nanowires to those of individual pure Cu nanowires and to those of alloy Fe30Co61Cu9 nanowires. The multilayered nanowires with a 50 nm diameter had a remarkable resistivity of approximately 5.41 × 10-7 Ω m and a failure current density of 1.54 × 1011 A m-2. Detailed analysis of the electrical data reveals that interfacial transition layers influence the electrical properties of multilayered nanowires and are likely to have a strong impact on the life of nanodevices. This work contributes to a basic understanding of the electrical parameters of individual magnetic multilayered nanowires for their application as functional building blocks and interconnecting leads in nanodevices and nanoelectronics, and also provides a clear physical picture of a single multilayered nanowire which explains its electrical resistance and its source of giant magnetoresistance. © The Royal Society of Chemistry 2016.

Teores de Fe, Mn, Zn, Cu, Ni E Co em solos de referência de Pernambuco Concentrations of Fe, Mn, Zn, Cu, Ni and Co in benchmark soils of Pernambuco, Brazil

Directory of Open Access Journals (Sweden)

Caroline Miranda Biondi

2011-06-01

Full Text Available Metais pesados formam um grupo de elementos com particularidades relevantes e de ocorrência natural no ambiente, como elementos acessórios na constituição de rochas. Esses elementos, apesar de associados à toxidez, exigem tratamento diferenciado em relação aos xenobióticos, uma vez que diversos metais possuem essencialidade (Fe, Mn, Cu, Zn e Ni e benefício (Co comprovados para as plantas. Nesse contexto, o objetivo deste trabalho foi determinar os teores naturais dos metais Fe, Mn, Zn, Ni, Cu e Co nos solos de referência de Pernambuco. Foram coletadas amostras de solo nas três regiões fisiográficas (Zona da Mata, Agreste e Sertão, dos dois primeiros horizontes dos 35 solos de referência do Estado de Pernambuco. A digestão das amostras baseou-se no método 3051A (USEPA, 1998, e a determinação foi efetuada em ICP-OES. Correlações significativas foram estabelecidas entre os metais e entre estes e a fração argila do solo, em ambos os horizontes, indicando a associação comum da maioria dos metais com solos mais argilosos. A maioria dos solos apresentou teores de Fe, Mn, Zn, Cu, Ni e Co menores que os de solos de outras regiões do País, com litologia mais máfica, o que corrobora o fato de que os teores desses elementos são mais diretamente relacionados aos minerais Fe-magnesianos. Os resultados indicam baixo potencial dos solos de Pernambuco em liberar Cu, Co e Ni para plantas, enquanto deficiências de Zn, Fe e Mn são menos prováveis. Os teores naturais de Fe, Mn, Zn, Cu, Ni e Co determinados podem ser utilizados como base para definição dos Valores de Referência de Qualidade para os solos de Pernambuco, de acordo com o preconizado pela legislação nacional.Heavy metals are a group of elements with specific features and natural occurrence in the environment, representing an accessory in the formation of rocks. These elements, although associated with toxicity, must be treated different from xenobiotics, since many

Radiation enhanced copper clustering processes in Fe-Cu alloys during electron and ion irradiations as measured by electrical resistivity

International Nuclear Information System (INIS)

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

2003-01-01

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

Moessbauer study of (Fe1-x Cu x )4N (0.05≤x≤0.15) films

International Nuclear Information System (INIS)

El Khiraoui, S.; Sajieddine, M.; Vergnat, M.; Bauer, Ph.; Mabrouki, M.

2007-01-01

In this work, we have prepared nitrogenated Fe 1- x Cu x alloys by reactive evaporation under a flow of nitrogen ions. After annealing, X-ray diffraction shows that we have synthesized the γ'-(Fe 1- x Cu x ) 4 N (0.05≤x≤0.15) compounds. The films were investigated by Moessbauer spectroscopy. The crystallographic structure and the respective positions of the Fe and Cu atoms in the compounds have been determined

Mecano-synthesis of the alloy 25%Fe-50%Cu-25%Nb; Mecano-sintese da liga 25%Fe-50%Cu-25%Nb

Energy Technology Data Exchange (ETDEWEB)

Sousa, Keytiane; Oliveira, Michel Picanco de; Guimaraes, Renan da Silva; Moreira Junior, Valdenir; Filgueira, Marcello, E-mail: marcello.filgueira@pq.cnpq.br [Universidade Estadual do Norte Fluminense (CCT/LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil)

2016-07-01

In general, this study aims at the application of mechanical grinding to the system 25% Fe-50% Cu-25% Nb and studies the production process of these powders during milling. The evolution of the structure during the synthesis and the effect of variation of the grinding time were studied by diffraction of X-rays (XRD) and Scanning Electron Microscopy coupled EDS (SEM + EDS) in order to obtain the sizes of crystallites, the phase formation and its evolution with grinding time, and also the homogeneity of the mixture. The particle size distribution was analyzed by laser sedigraph technique. The powders synthesis were performed for milling time of 2.5, 5 and 10 hours. The mechanical grinding showed to be effective with the solid solution formation in the early grinding times. The XRD showed the solid solution formation with subsequent reduction and disappearance of Cu peaks. Through the technique of laser sedigraph it was observed the increase of the particle size followed by the its reduction in the milling time of 10h, a fact that characterizes the mechanical grinding process for ductile powder particles. Thus, the study demonstrated the effectiveness of the mechanical grinding to obtain powder of Fe-Cu-Nb and further processing and application of diamond cutting tools. (author)

Structural and dynamical heterogeneity of undercooled Fe{sub 75}Cu{sub 25} melts with miscibility gap

Energy Technology Data Exchange (ETDEWEB)

Qi, Yu; Wang, Li; Wang, Shenghai, E-mail: shenghaiw@163.com; Li, Xuelian; Cui, Wenchao

2014-12-05

Highlights: • We simulate the undercooled Fe{sub 75}Cu{sub 25} melts with miscibility gap at atomic level. • Fe{sub 75}Cu{sub 25} melts separate into Cu-rich and Fe-rich liquid upon relaxation. • The process is controlled by the nucleation and grows mechanism. • Both PPCFs and CN confirm that L–L phase separation is a successive process. - Abstract: Molecular dynamics simulation (MD) based upon the developed embedded atom method (EAM) has been performed to explore the structural and dynamical heterogeneity of Fe{sub 75}Cu{sub 25} melts. The results show that the melts separate into Cu-rich droplets surround by the Fe-rich matrix controlled by nucleation and growth mechanism. The larger undercoolings suggest the higher nucleation rate and growth rate of droplets. The growth of droplet is achieved by the aggregation and coagulation of neighbor droplet with the characteristics of collective movement for homogeneous atoms. A sharp increase of S{sub CC} (q = 0) is found at all simulated temperature, which means concentration fluctuation on large length scales are much pronounced. Both partial pair correlation functions (PPCFs) and coordination number (CN) confirm that liquid–liquid (L–L) phase separation is a successive process with a stronger interaction of homogeneous pairs than that of heterogeneous pairs in Fe{sub 75}Cu{sub 25} melts. The studies above characterize the phase separation of metal melts on the atomic scale.

DFT predictions, synthesis, stoichiometric structures and anti-diabetic activity of Cu (II) and Fe (III) complexes of quercetin, morin, and primuletin

Science.gov (United States)

Jabeen, Erum; Janjua, Naveed Kausar; Ahmed, Safeer; Murtaza, Iram; Ali, Tahir; Masood, Nosheen; Rizvi, Aysha Sarfraz; Murtaza, Gulam

2017-12-01

The current study is aimed at the synthesis of Cu (II) and Fe (III) complexes of three flavonoids {morin (mor), quercetin (quer) and primuletin (prim)} and characterization through UV-Vis spectroscopy, cyclic voltammetry, FTIR, and thermal analysis. Structure prediction through DFT calculation was supported by experimental data. Benesi-Hildebrand equation was modified to function for 1:2 Cu-flavonoid and 1:3 Fe-flavonoid complexes. DFT predictions revealed that out of poly chelation sites present in morin and quercetin, 3-OH site was utilized as preferable chelation site while primuletin chelated through 5-OH position. In-vivo trials revealed the complexes to have better anti-diabetic potential than respective flavonoid. Fls/M-Fls proved as antagonistic to Alloxan induced diabetes and also retained anti-diabetic activity even in the presence of (2-hydroxypropyl)-β-cyclodextrin (HPβCD).

Charge dynamics of 57Fe probe atoms in La2Li0.5Cu0.5O4

Science.gov (United States)

Presniakov, I. A.; Sobolev, A. V.; Rusakov, V. S.; Moskvin, A. S.; Baranov, A. V.

2018-06-01

The objective of this study is to characterize the electronic state and local surrounding of 57Fe Mössbauer probe atoms within iron-doped layered perovskite La2Li0.5Cu0.5O4 containing transition metal in unusual formal oxidation states "+3". An approach based on the qualitative energy diagrams analysis and the calculations within the cluster configuration interaction method have been developed. It was shown that a large amount of charge is transferred via Cu-O bonds from the O: 2p bands to the Cu: 3d orbitals and the ground state is dominated by the d9L configuration ("Cu2+-O-" state). The dominant d9L ground state for the (CuO6) sublattice induces in the environment of the 57Fe probe cations a charge transfer Fe3+ + O-(L) → Fe4+ + O2-, which transforms "Fe3+" into "Fe4+" state. The experimental spectra in the entire temperature range 77-300 K were described with the use of the stochastic two-level model based on the assumption of dynamic equilibrium between two Fe3+↔Fe4+ valence states related to the iron atom in the [Fe(1)O4]4- center. The relaxation frequencies and activation energies of the corresponding charge fluctuations were estimated based on Mössbauer data. The results are discussed assuming a temperature-induced change in the electronic state of the [CuO4]5- clusters in the layered perovskite.

Magnetically separable Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposites: Preparation, characterization and visible-light photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Cao, Chunhua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@whu.edu.cn [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Cao, Qihua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China)

2015-04-01

Highlights: • A novel magnetically-separable Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} photocatalyst was in situ prepared. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs had rough and porous chitosan surface layer embedded with Fe{sub 3}O{sub 4} NPs. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed large surface areas and special dimodal pore structure. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed superparamagnetism and could be easily magnetic separated. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited good visible-light photocatalytic activity and stability. - Abstract: A novel magnetically-separable visible-light-induced photocatalyst, Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposite (Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NC), was prepared via a facile one-step precipitation–reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV–vis/DRS. The photocatalytic activity of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu{sub 2}O was wrapped in chitosan matrix embedded with Fe{sub 3}O{sub 4} nanoparticles. The tight combination of magnetic Fe{sub 3}O{sub 4} and semiconductor Cu{sub 2}O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B

A Hybrid Mineral Battery: Energy Storage and Dissolution Behavior of CuFeS2 in a Fixed Bed Flow Cell.

Science.gov (United States)

Deen, Kashif Mairaj; Asselin, Edouard

2018-05-09

The development of a hybrid system capable of storing energy and the additional benefit of Cu extraction is discussed in this work. A fixed bed flow cell (FBFC) was used in which a composite negative electrode containing CuFeS 2 (80 wt %) and carbon black (20 wt %) in graphite felt was separated from a positive (graphite felt) electrode by a proton-exchange membrane. The anolyte (0.2 m H 2 SO 4 ) and catholyte (0.5 m Fe 2+ in 0.2 m H 2 SO 4 with or without 0.1 m Cu 2+ ) were circulated in the cell. The electrochemical activity of the Fe 2+ /Fe 3+ redox couple over graphite felt significantly improved after the addition of Cu 2+ in the catholyte. Ultimately, in the CuFeS 2 ∥Fe 2+ /Cu 2+ (CFeCu) FBFC system, the specific capacity increased continuously to 26.4 mAh g -1 in 500 galvanostatic charge-discharge (GCD) cycles, compared to the CuFeS 2 ∥Fe 2+ (CFe) system (13.9 mAh g -1 ). Interestingly, the specific discharge energy gradually increased to 3.6 Wh kg -1 in 500 GCD cycles for the CFeCu system compared to 3.29 Wh kg -1 for the CFe system in 150 cycles. In addition to energy storage, 10.75 % Cu was also extracted from the mineral, which is an important feature of the CFeCu system as it would allow Cu extraction and recovery through hydrometallurgical methods. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Reaction Mechanism and Rate Constants in the Radiolysis of Fe2+-Cu2+ Solutions

DEFF Research Database (Denmark)

Bjergbakke, Erling; Sehested, Knud; Rasmussen, O. Lang

1976-01-01

Pulse radiolysis and gamma radiolysis have been used to study the reaction mechanism in the radiolysis of aqueous solutions of Fe2+ and Cu2+. A reaction scheme has been developed and confirmed by computation of the corresponding complete set of differential equations. The rate constants for some ...... 10^{8}$ and $1.3\\times 10^{8}\\ {\\rm mol}^{-1}\\ {\\rm sec}^{-1}$ in pH 2.1 H2 SO4 and HClO4, respectively.......Pulse radiolysis and gamma radiolysis have been used to study the reaction mechanism in the radiolysis of aqueous solutions of Fe2+ and Cu2+. A reaction scheme has been developed and confirmed by computation of the corresponding complete set of differential equations. The rate constants for some...... of the reactions have been determined at different pH's. $k_{{\\rm Cu}^{+}+{\\rm O}_{2}}=4.6\\times 10^{5}$ and $1.0\\times 10^{6}\\ {\\rm mol}^{-1}\\ {\\rm sec}^{-1}$, $k_{{\\rm Cu}^{+}+{\\rm Fe}^{3+}}=5.5\\times 10^{6}$ and $1.3\\times 10^{7}\\ {\\rm mol}^{-1}\\ {\\rm sec}^{-1}$, $k_{{\\rm Cu}({\\rm III)}+{\\rm Fe}^{2+}}=3.3\\times...

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

Quantitative trait loci controlling Cu, Ca, Zn, Mn and Fe content in ...

Indian Academy of Sciences (India)

of essential minerals (such as Fe, Zn etc), breeding mineral- efficient crops that produce .... and seven digenic interactions were identified for Cu, Ca,. Zn, Mn and Fe, .... Eva P. 1993 Cadmium, copper and lead in wild rice from central. Canada.

Influence of the spacer layer on microstructure and magnetic properties of [NdFeB/(NbCu)]xn thin films

Energy Technology Data Exchange (ETDEWEB)

Chiriac, H. [National Institute of R and D for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania); Grigoras, M. [National Institute of R and D for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania); Urse, M. [National Institute of R and D for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania)]. E-mail: urse@phys-iasi.ro

2007-09-15

Some results concerning the influence of the composition and thickness of NbCu spacer layer on the microstructure and magnetic properties of multilayer [NdFeB/(NbCu)]xn films, in view of their utilization for manufacturing the thin film permanent magnets are presented. A comparison between the microstructure and magnetic properties of NdFeB single layer and [NdFeB/(NbCu)]xn multilayer is also presented. The multilayer [NdFeB/(NbCu)]xn thin films with the thickness of the NdFeB layer of 180nm and the thickness of the NbCu spacer layer of 3nm, exhibit good hard magnetic characteristics such as coercive force H{sub c} of about 1510kA/m and the remanence ratio M{sub r}/M{sub s} of about 0.8.

Influence of the spacer layer on microstructure and magnetic properties of [NdFeB/(NbCu)]xn thin films

International Nuclear Information System (INIS)

Chiriac, H.; Grigoras, M.; Urse, M.

2007-01-01

Some results concerning the influence of the composition and thickness of NbCu spacer layer on the microstructure and magnetic properties of multilayer [NdFeB/(NbCu)]xn films, in view of their utilization for manufacturing the thin film permanent magnets are presented. A comparison between the microstructure and magnetic properties of NdFeB single layer and [NdFeB/(NbCu)]xn multilayer is also presented. The multilayer [NdFeB/(NbCu)]xn thin films with the thickness of the NdFeB layer of 180nm and the thickness of the NbCu spacer layer of 3nm, exhibit good hard magnetic characteristics such as coercive force H c of about 1510kA/m and the remanence ratio M r /M s of about 0.8

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)

The synthesis of Cu/Fe/Fe3O4 catalyst through the aqueous solution ball milling method assisted by high-frequency electromagnetic field

Science.gov (United States)

Yingzhe, Zhang; Yuxing, He; Qingdong, Qin; Fuchun, Wang; Wankun, Wang; Yongmei, Luo

2018-06-01

In this paper, nano-magnetic Cu/Fe/Fe3O4 catalyst was prepared by a new aqueous solution ball milling method assisted by high-frequency electromagnetic field at room temperature. The products were characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), selected area electron diffraction (SAED), and vibrating sample magnetometer (VSM). Microwave induced catalytic degradation of methylene blue (MB) was carried out in the presence of Cu/Fe/Fe3O4. The concentration of methylene blue was determined by UV-Vis spectrophotometry. The solid catalyst showed high catalytic activity of degrade MB and considerable saturation magnetization, lower remanence and coercivity. It indicate that the catalyst can be effectively separated for reuse by simply applying an external magnetic field and it can greatly promote their potential industrial application to eliminate organic pollutants from waste-water. Finally, we found that it is the non-thermal effect of microwave that activated the catalytic activity of Cu/Fe/Fe3O4 to degrade MB.

Synthesis of Ag-Cu and Ag-Cu{sub 2}O alloy nanoparticles using a seed-mediated polyol process, thermodynamic and kinetic aspects

Energy Technology Data Exchange (ETDEWEB)

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

2017-03-01

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

Microwave catalytic NOx and SO{sub 2} removal using FeCu/zeolite as catalyst

Energy Technology Data Exchange (ETDEWEB)

Z.S. Wei; G.H. Zeng; Z.R. Xie; C.Y. Ma; X.H. Liu; J.L. Sun; L.H. Liu [Sun Yat-sen University, Guangzhou (China). School of Environmental Science and Engineering

2011-04-15

Non-thermal plasma technology is a promising process for flue gas treatment. Microwave catalytic NOx and SO{sub 2} removal simultaneously has been investigated using FeCu/zeolite as catalyst. The experimental results showed that a microwave reactor with FeCu/zeolite only could be used to microwave catalytic oxidative 91.7% NOx to nitrates and 79.6% SO{sub 2} to sulfate; the reaction efficiencies of microwave catalytic reduction of NOx and SO{sub 2} in a microwave reactor with FeCu/zeolite and ammonium bicarbonate (NH{sub 4}HCO{sub 3}) as a reducing agent could be up to 95.8% and 93.4% respectively. Microwave irradiation accentuates catalytic reduction of SO{sub 2} and NOx treatment, and microwave addition can increases SO{sub 2} removal efficiency from 14.5% to 18.7%, and NOx removal efficiency from 13.4% to 18.7%, separately. FeCu/zeolite catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectrum analysis (XPS), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic NOx and SO{sub 2} removal follows Langmuir-Hinshelwood (L-H) kinetics. 25 refs., 7 figs., 1 tab.

Fe(II)/Cu(II) interaction on goethite stimulated by an iron-reducing bacteria Aeromonas Hydrophila HS01 under anaerobic conditions.

Science.gov (United States)

Tao, Liang; Zhu, Zhen-Ke; Li, Fang-Bai; Wang, Shan-Li

2017-11-01

Copper is a trace element essential for living creatures, but copper content in soil should be controlled, as it is toxic. The physical-chemical-biological features of Cu in soil have a significant correlation with the Fe(II)/Cu(II) interaction in soil. Of significant interest to the current study is the effect of Fe(II)/Cu(II) interaction conducted on goethite under anaerobic conditions stimulated by HS01 (a dissimilatory iron reduction (DIR) microbial). The following four treatments were designed: HS01 with α-FeOOH and Cu(II) (T1), HS01 with α-FeOOH (T2), HS01 with Cu(II) (T3), and α-FeOOH with Cu(II) (T4). HS01 presents a negligible impact on copper species transformation (T3), whereas the presence of α-FeOOH significantly enhanced copper aging contributing to the DIR effect (T1). Moreover, the violent reaction between adsorbed Fe(II) and Cu(II) leads to the decreased concentration of the active Fe(II) species (T1), further inhibiting reactions between Fe(II) and iron (hydr)oxides and decelerating the phase transformation of iron (hydr)oxides (T1). From this study, the effects of the Fe(II)/Cu(II) interaction on goethite under anaerobic conditions by HS01 are presented in three aspects: (1) the accelerating effect of copper aging, (2) the reductive transformation of copper, and (3) the inhibition effect of the phase transformation of iron (hydr)oxides. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quasicrystalline phase formation in the mechanically alloyed Al{sub 70}Cu{sub 20}Fe{sub 10}

Energy Technology Data Exchange (ETDEWEB)

Medeiros, S. N. de, E-mail: snm@dfi.uem.br; Cadore, S.; Pereira, H. A.; Santos, I. A.; Colucci, C. C.; Paesano, A. [Universidade Estadual de Maringa, Departamento de Fisica (Brazil)

2010-01-15

In the present work, the formation of the Al{sub 70}Cu{sub 20}Fe{sub 10} icosahedral phase by mechanical alloying the elemental powders in a high-energy planetary mill was investigated by X-ray diffraction and Moessbauer spectroscopy. It was verified that the sample milled for 80 h produces an icosahedral phase besides Al(Cu, Fe) solid solution ({beta}-phase) and Al{sub 2}Cu intermetallic phase. The Moessbauer spectrum for this sample was fitted with a distribution of quadrupole splitting, a doublet and a sextet, revealing the presence of the icosahedral phase, {beta}-phase and {alpha}-Fe, respectively. This compound is not a good hydrogen storage. The results of the X-ray diffraction and Moessbauer spectroscopy of the sample milled for 40 h and annealed at 623 deg. C for 16 h shows essentially single i-phase and tetragonal Al{sub 7}Cu{sub 2} Fe phase.

Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of Nanostructural Features in Irradiated Fe-Cu-Mn Alloys

International Nuclear Information System (INIS)

Wirth, B D; Asoka-Kumar, P; Howell, R H; Odette, G R; Sterne, P A

2001-01-01

Radiation embrittlement of nuclear reactor pressure vessel steels results from a high number density of nanometer sized Cu-Mn-Ni rich precipitates (CRPs) and sub-nanometer matrix features, thought to be vacancy-solute cluster complexes (VSC). However, questions exist regarding both the composition of the precipitates and the defect character and composition of the matrix features. We present results of positron annihilation spectroscopy (PAS) and small angle neutron scattering (SANS) characterization of irradiated and thermally aged Fe-Cu and Fe-Cu-Mn alloys. These complementary techniques provide insight into the composition and character of both types of nanoscale features. The SANS measurements indicate populations of CRPs and VSCs in both alloys. The CRPs are coarser in the Fe-Cu alloy and the number densities of CRP and VSC increase with the addition of Mn. The PAS involved measuring both the positron lifetimes and the Doppler broadened annihilation spectra in the high momentum region to provide elemental sensitivity at the annihilation site. The spectra in Fe-Cu-Mn specimens thermally aged to peak hardness at 450 C and irradiated at 288 C are nearly identical to elemental Cu. Positron lifetime and spectrum measurements in Fe-Cu specimens irradiated at 288 C clearly show the existence of long lifetime (∼500 ps) open volume defects, which also contain Cu. Thus the SANS and PAS provide a self-consistent picture of nanostructures composed of CRPs and VSCs and tend to discount high Fe concentrations in the CRPs

Leaching of rapidly quenched Al65Cu20Fe15 quasicrystalline ribbons

Indian Academy of Sciences (India)

2017-12-06

Dec 6, 2017 ... stood that Al–Cu–Fe QC also presents an FCI structure similar to that .... that the precipitation rate of Fe is lower than that of Cu. Figure 2a shows the .... Renewable Energy (MNRE), India, under Mission Mode. Hydrogen ...

Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

International Nuclear Information System (INIS)

Du, Jiandi; Ding, Dongyan; Xu, Zhou; Zhang, Junchao; Zhang, Wenlong; Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua; Chen, Renzong; Huang, Yuanwei; Tang, Jinsong

2017-01-01

Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al 8 Cu 4 Ce phase, Al 6 Cu 6 La phase and Al 6 (Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

Fabrication of magnetically recyclable Fe3O4@Cu nanocomposites with high catalytic performance for the reduction of organic dyes and 4-nitrophenol

International Nuclear Information System (INIS)

Tang, Mingyi; Zhang, Sai; Li, Xianxian; Pang, Xiaobo; Qiu, Haixia

2014-01-01

A facile and efficient approach to synthesize Fe 3 O 4 @Cu nanocomposites using L-Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe 3 O 4 @Cu nanocomposites were characterized by Fourier Transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. In addition, the magnetic properties were determined with vibrating sample magnetometer. The surface of the Fe 3 O 4 contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe 3 O 4 @Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe 3 O 4 @Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe 3 O 4 @Cu nanocomposites are more efficient catalysts compared with Cu nanoparticles and can easily be recovered from the reaction mixture with magnet. The cost effective and recyclable Fe 3 O 4 @Cu nanocomposites provide an exciting new material for environmental protection applications. - Highlights: • Cu nanoparticles as small as 3 nm are synthesized. • Low cost Fe 3 O 4 @Cu magnetical nanoparticles show catalytic activity for organic dyes and 4-nitrophenol. • The Fe 3 O 4 @Cu display high catalytic activity after 13 cycles

Fe site occupancy and superconductivity in Y1-zCazBaz(Cu1-xFex)3O6+y

International Nuclear Information System (INIS)

Smith, M.G.; Taylor, R.D.; Oesterreicher, H.

1990-01-01

X-ray diffraction and 57 Fe Moessbauer spectroscopy studies show that partial substitution of Ca for Y in Y 1-z Ca z Ba 2 (Cu 1-x Fe x ) 3 O 6+y (0.05 ≤ z ≤ 0.15,0.003 ≤ x ≤ 0.20) result in increased Fe solubility and a larger percentage of Fe occupancy of the Cu(2) plane site (prepared conventionally). Materials with z > 0.00 have a slightly depressed superconducting transition onset temperature T c relative to the z = 0.00 compounds. It is also shown that Fe occupancy of the Cu(2) site in Y 1-z Ca z Ba 2 (Cu 1-x Fe x ) 3 O 6+y can be substantially increased when these materials are treated at high temperatures in inert atmospheres followed by oxygenation at low temperatures. T c decreases more rapidly in these latter materials compared to the conventionally prepared ones. Implications concerning ordered Fe cluster formation and superconducting pair breaking in the Cu(2) site are drawn. 7 refs., 4 tabs

Quantum-well states and induced magnetism in Fe/CuN/Fe bcc (001) trilayers

DEFF Research Database (Denmark)

Niklasson, A.M.N.; Mirbt, S.; Skriver, Hans Lomholt

1996-01-01

profiles of two single Fe/Cu interfaces. The small deviations from this simple superposition are shown to be a consequence of quantum-well states confined within the paramagnetic spacer. This connection is confirmed by direct calculation of the state density. The results are of conceptual interest...

Fe-contacts on InAs(100) and InP(100) characterised by conversion electron Mössbauer spectroscopy

DEFF Research Database (Denmark)

Damsgaard, Christian Danvad; Gunnlaugsson, H.P; Weyer, G.

2005-01-01

We have grown 4 nm thin films of Fe-57 on InAs(100) and InP(100) surfaces by use of MBE and studied the samples by Fe-57 conversion electron Mossbauer spectroscopy. In the case of InAs, the Mossbauer spectrum showed a sextet due to alpha-Fe and a further magnetically split component with slightly...

Magnetic and electronic properties of Cu1-xFexO from first principles calculations

KAUST Repository

Yang, Hua; Cheng, Yingchun; Chen, Guifeng; Mi, Wenbo; Bai, Haili

2013-01-01

Magnetic and electronic properties of Cu1-xFexO systems with x = 6.25% and 12.5% have been investigated using first principles calculations. The ground state of CuO is an antiferromagnetic insulator. At x = 6.25%, Cu1-xFexO systems with Fe on 2 and 4 substitution positions are half-metallic due to the strong hybridization among Fe, the nearest O and Cu atoms, which may come from the double exchange coupling between Fe2+-O2--Cu2+. At x = 12.5%, Cu 1-xFexO system with Fe on 9-11 position has a strong spin polarization near the Fermi level and the system energy is lowest when the doped two Fe atoms form ferromagnetic configuration. This indicates the two doped Fe atoms prefer to form ferromagnetic configuration in Fe2+-O 2--Cu2+-O2--Fe2+ chains. While in the Fe on 7-11 position, the spin-down Fe-11 3d states have a large spin polarization near the Fermi level when the two doped Fe atoms form antiferromagnetic configuration. It is concluded that the transition metal doping can modify the magnetism and electronic structures of Cu 1-xFexO systems. This journal is © The Royal Society of Chemistry 2013.

The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

OpenAIRE

Travessa, Dilermando Nagle; Cardoso, Kátia Regina; Wolf, Witor; Jorge Junior, Alberto Moreira; Botta, Walter José

2012-01-01

In order to obtain quasicrystalline (QC) phase by mechanical alloying (MA) in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. %) were produced by high energy ball milling (HEBM). A very high energy type mill (spex) and short milling times (up to 5 hours) were employed. The resulting powders were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). QC phase was not directly formed ...

A Question of Balance: Facing the challenges of Cu, Fe and Zn Homeostasis

OpenAIRE

Palmer, Christine; Guerinot, Mary Lou

2009-01-01

Plants have recently moved into the spotlight with the growing realization that the world needs solutions to energy and food production that are sustainable and environmentally sound. Iron (Fe), copper (Cu), and zinc (Zn) are essential for plant growth and development, yet the same properties that make these transition metals indispensable can also make them deadly in excess. Fe and Cu are most often utilized for their redox properties, while Zn is primarily utilized for is ability to act as ...

Silicon induced Fe deficiency affects Fe, Mn, Cu and Zn distribution in rice (Oryza sativa L.) growth in calcareous conditions.

Science.gov (United States)

Carrasco-Gil, Sandra; Rodríguez-Menéndez, Sara; Fernández, Beatriz; Pereiro, Rosario; de la Fuente, Vicenta; Hernandez-Apaolaza, Lourdes

2018-04-01

A protective effect by silicon in the amelioration of iron chlorosis has recently been proved for Strategy 1 species, at acidic pH. However in calcareous conditions, the Si effect on Fe acquisition and distribution is still unknown. In this work, the effect of Si on Fe, Mn, Cu and Zn distribution was studied in rice (Strategy 2 species) under Fe sufficiency and deficiency. Plants (+Si or-Si) were grown initially with Fe, and then Fe was removed from the nutrient solution. The plants were then analysed using a combined approach including LA-ICP-MS images for each element of interest, the analysis of the Fe and Si concentration at different cell layers of root and leaf cross sections by SEM-EDX, and determining the apoplastic Fe, total micronutrient concentration and oxidative stress indexes. A different Si effect was observed depending on plant Fe status. Under Fe sufficiency, Si supply increased Fe root plaque formation, decreasing Fe concentration inside the root and increasing the oxidative stress in the plants. Therefore, Fe acquisition strategies were activated, and Fe translocation rate to the aerial parts was increased, even under an optimal Fe supply. Under Fe deficiency, +Si plants absorbed Fe from the plaque more rapidly than -Si plants, due to the previous activation of Fe deficiency strategies during the growing period (+Fe + Si). Higher Fe plaque formation due to Si supply during the growing period reduced Fe uptake and could activate Fe deficiency strategies in rice, making it more efficient against Fe chlorosis alterations. Silicon influenced Mn and Cu distribution in root. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Thermodynamic analysis of binary Fe{sub 85}B{sub 15} to quinary Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloys for primary crystallizations of α-Fe in nanocrystalline soft magnetic alloys

Energy Technology Data Exchange (ETDEWEB)

Takeuchi, A., E-mail: takeuchi@imr.tohoku.ac.jp; Zhang, Y.; Takenaka, K.; Makino, A. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2015-05-07

Fe-based Fe{sub 85}B{sub 15}, Fe{sub 84}B{sub 15}Cu{sub 1}, Fe{sub 82}Si{sub 2}B{sub 15}Cu{sub 1}, Fe{sub 85}Si{sub 2}B{sub 12}Cu{sub 1}, and Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} (NANOMET{sup ®}) alloys were experimental and computational analyzed to clarify the features of NANOMET that exhibits high saturation magnetic flux density (B{sub s}) nearly 1.9 T and low core loss than conventional nanocrystalline soft magnetic alloys. The X-ray diffraction analysis for ribbon specimens produced experimentally by melt spinning from melts revealed that the samples were almost formed into an amorphous single phase. Then, the as-quenched samples were analyzed with differential scanning calorimeter (DSC) experimentally for exothermic enthalpies of the primary and secondary crystallizations (ΔH{sub x1} and ΔH{sub x2}) and their crystallization temperatures (T{sub x1} and T{sub x2}), respectively. The ratio ΔH{sub x1}/ΔH{sub x2} measured by DSC experimentally tended to be extremely high for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy, and this tendency was reproduced by the analysis with commercial software, Thermo-Calc, with database for Fe-based alloys, TCFE7 for Gibbs free energy (G) assessments. The calculations exhibit that a volume fraction (V{sub f}) of α-Fe tends to increase from 0.56 for the Fe{sub 85}B{sub 15} to 0.75 for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy. The computational analysis of the alloys for G of α-Fe and amorphous phases (G{sub α-Fe} and G{sub amor}) shows that a relationship G{sub α-Fe} ∼ G{sub amor} holds for the Fe{sub 85}Si{sub 2}B{sub 12}Cu{sub 1}, whereas G{sub α-Fe} < G{sub amor} for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy at T{sub x1} and that an extremely high V{sub f} = 0.75 was achieved for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy by including 2.8 at. % Si and 4.5 at. % P into α-Fe. These computational results indicate that the Fe{sub 85}Si{sub 2}B

Distorted chain sites for Co- and Fe-substituted YBa2Cu3O/sub 7-δ/

International Nuclear Information System (INIS)

Bridges, F.; Boyce, J.B.; Claeson, T.; Geballe, T.H.; Tarascon, J.M.; Xerox Palo Alto Research Center, Palo Alto, California 94304; Physics Department, Chalmers University of Technology, S-41296 Gothenburg, Sweden; Department of Applied Physics, Stanford University, Stanford, California 94305; Bell Communications Research Laboratory, Red Bank, New Jersey 07701)

1989-01-01

We present x-ray-absorption fine-structure (XAFS) measurements for a series of Co- and Fe-substituted samples of YBa 2 Cu 3 O/sub 7-δ/(Y-Ba-Cu-O). Our analysis of the first- and second-neighbor environments indicates that the Co atoms primarily replace the Cu in the chain sites, the Cu(1) atoms, in Y-Ba-Cu-O, but many of these Co(1) sites and their neighboring oxygen sites are highly distorted. The first-neighbor Co-O peak consists of approximately 3.5 oxygen at 1.8 A and approximately 1.3 oxygen at 2.4 A, while the second-neighbor multipeak in the XAFS data is unexpectedly low in amplitude. Structure in this peak is inconsistent with a simple Gaussian broadening and indicates that several Co(1)-Ba distances exist. We propose an aggregation of the Co atoms into distorted, zigzag chains along the directions, with some of the Co displaced off center by approximately 0.4 A along a perpendicular direction. This model is consistent with the second-neighbor XAFS data, provides an explanation for the tetragonal structure via twinning on a microscopic scale, and accommodates excess oxygen within the Co chains. The Fe data suggest that similar chains also exist in the Fe-substituted samples. There are, however, some differences between the local environments of the Fe and Co. The primary difference is that a small but significant number of Fe atoms occupy the Cu(2) plane sites while no appreciable number of Co atoms are found on the Cu(2) sites in the more dilute samples. Finally, near-edge measurements on the Co and Fe K-absorption edges indicate that the valence is primarily +3, but a mixture of valences exists. For Co the edge position corresponds to a mixture of +2 and +3 valences, while Fe exists in a mixture of +2, +3, and +4 states

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

Synthesis of highly efficient α-Fe{sub 2}O{sub 3} catalysts for CO oxidation derived from MIL-100(Fe)

Energy Technology Data Exchange (ETDEWEB)

Cui, Lifeng; Zhao, Di; Yang, Yang [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Wang, Yuxin [Institute of Applied Biotechnology, Taizhou Vocation & Technical College, Taizhou, Zhejiang 318000 (China); Zhang, Xiaodong, E-mail: fatzhxd@126.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China)

2017-03-15

Mesoporous hollow α-Fe{sub 2}O{sub 3} bricks were synthesized via a hydrothermal method to create a precursor MIL-100(Fe) and a subsequent calcination process was applied to prepare the Fe{sub 2}O{sub 3} phase. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results showed the morphology of hollow α-Fe{sub 2}O{sub 3} bricks which inherited from the MIL-100(Fe) template. The catalytic activities of hollow α-Fe{sub 2}O{sub 3} bricks for CO oxidation are studied in this work. Due to better low temperature reduction behavior, mesoporous hollow α-Fe{sub 2}O{sub 3} bricks obtained at calcination temperature of 430 °C displayed high catalytic activity and excellent stability with a complete CO conversion temperature (T{sub 100}) of 255 °C. - Graphical abstract: Synthesis of highly efficient α-Fe{sub 2}O{sub 3} catalysts for CO oxidation derived from MIL-100(Fe). - Highlights: • α-Fe{sub 2}O{sub 3} is prepared by the thermolysis of a MIL-100(Fe) template. • The morphology of hollow α-Fe{sub 2}O{sub 3} bricks is inherited from MIL-100(Fe) template. • α-Fe{sub 2}O{sub 3} obtained at calcined temperature of 430 °C displays high activity • Enhanced activity is attributed to crystal plane and reduction behavior.

Enhanced photocatalytic, electrochemical and photoelectrochemical properties of TiO2 nanotubes arrays modified with Cu, AgCu and Bi nanoparticles obtained via radiolytic reduction

International Nuclear Information System (INIS)

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

2016-01-01

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

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

Science.gov (United States)

Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

2018-04-01

This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity (H c > 10 kOe) can be achieved without any microstructural refinement.

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

Science.gov (United States)

Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

2018-06-01

This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.

Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

Energy Technology Data Exchange (ETDEWEB)

Du, Jiandi [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Ding, Dongyan, E-mail: dyding@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, Zhou; Zhang, Junchao; Zhang, Wenlong [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua [Huafon NLM Al Co., Ltd, Shanghai 201506 (China); Chen, Renzong; Huang, Yuanwei; Tang, Jinsong [Shanghai Huafon Materials Technology Institute, Shanghai 201203 (China)

2017-01-15

Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al{sub 8}Cu{sub 4}Ce phase, Al{sub 6}Cu{sub 6}La phase and Al{sub 6}(Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

Determination of Cu/Zn and Fe in human serum of patients with sickle cell anemia using radiation synchrotron

Energy Technology Data Exchange (ETDEWEB)

Canellas, C.G.L. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Carvalho, S.M.F. [State Institute of Hematology Arthur de Siqueira Cavalcanti, 20.211-030 Rio de Janeiro (Brazil); Anjos, M.J. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro, 20.559-900 Rio de Janeiro (Brazil); Lopes, R.T., E-mail: ricardo@lin.ufrj.br [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil)

2012-07-15

In this work we analyzed serum samples from patients with Sickle Cell Anemia (SCA) using Total Reflection X-Ray Fluorescence using Synchrotron Radiation (SRTXRF). The SRTXRF measurements were performed at the X-Ray Fluorescence Beamline at the Brazilian National Synchrotron Light Laboratory (LNLS). We studied forty-three patients aged 18-50 suffering from SCA and sixty healthy volunteers aged 18-60. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Moreover, there are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. The concentrations of Fe and Cu in the serum samples of patients with SCA were larger, 120% and 20%, respectively, when compared with the CG. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples from patients suffering from SCA than from the CG. Therefore, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. - Highlights: Black-Right-Pointing-Pointer Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. Black-Right-Pointing-Pointer It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Black-Right-Pointing-Pointer There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. Black-Right-Pointing-Pointer The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

Determination of Cu/Zn and Fe in human serum of patients with sickle cell anemia using radiation synchrotron

International Nuclear Information System (INIS)

Canellas, C.G.L.; Carvalho, S.M.F.; Anjos, M.J.; Lopes, R.T.

2012-01-01

In this work we analyzed serum samples from patients with Sickle Cell Anemia (SCA) using Total Reflection X-Ray Fluorescence using Synchrotron Radiation (SRTXRF). The SRTXRF measurements were performed at the X-Ray Fluorescence Beamline at the Brazilian National Synchrotron Light Laboratory (LNLS). We studied forty-three patients aged 18–50 suffering from SCA and sixty healthy volunteers aged 18–60. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Moreover, there are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. The concentrations of Fe and Cu in the serum samples of patients with SCA were larger, 120% and 20%, respectively, when compared with the CG. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples from patients suffering from SCA than from the CG. Therefore, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. - Highlights: ► Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. ► It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. ► There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. ► The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

Magnetic Properties Studies on Thermal Aged Fe-Cu Alloys for the Simulation of Radiation Damage

Energy Technology Data Exchange (ETDEWEB)

Lee, C. K.; Kishore, M.B.; Park, D. G. [KAERI, Daejeon (Korea, Republic of); Son, De Rac. [Hannam University, Daejeon (Korea, Republic of)

2016-05-15

We evaluated the changes in magnetic properties due to cold rolling and thermal ageing of a Fe-1%Cu model alloy in this study. Initially, the alloy was 10% cold rolled, and isothermally aged at 400 .deg. C for 1, 10, 100 and 1000 hr. The samples were prepared at various thermal aging conditions and all the conditions were interpreted. The hysteresis loops, Magnetic Barkhausen noise (BN). The change of magnetic properties can be interpreted in terms of the domain wall motion and dislocation dynamics associated with copper rich precipitates (CRPs).The results were interpreted in terms of ageing time dependence of the precipitates evolution such as the volume fraction and size distribution. In order to evaluate the radiation embrittlement of RPV steel, A Cold rolled Fe-Cu model Alloy was prepared, The prepared samples were thermally aged by annealing at 400 .deg. C for various times, the magnetic properties of the annealed samples were measured, The Barkhausen noise and BH Loop shows a considerable trend corresponding to the Ageing time. The magnetic properties were interpreted and correlated to the CRPs formed through annealing process.

Comparative study on the reactivity of Fe/Cu bimetallic particles and zero valent iron (ZVI) under different conditions of N2, air or without aeration.

Science.gov (United States)

Xiong, Zhaokun; Lai, Bo; Yang, Ping; Zhou, Yuexi; Wang, Juling; Fang, Shuping

2015-10-30

In order to further compare the degradation capacity of Fe(0) and Fe/Cu bimetallic system under different aeration conditions, the mineralization of PNP under different aeration conditions has been investigated thoroughly. The results show that the removal of PNP by Fe(0) or Fe/Cu system followed the pseudo-first-order reaction kinetics. Under the optimal conditions, the COD removal efficiencies obtained through Fe(0) or Fe/Cu system under different aeration conditions followed the trend that Fe/Cu (air)>Fe/Cu (N2: 0-30 min, air: 30-120 min)>control-Fe (air)>Fe/Cu (without aeration)>Fe/Cu (N2)>control-Fe (N2). It revealed that dissolved oxygen (DO) could improve the mineralization of PNP, and Cu could enhance the reactivity of Fe(0). In addition, the degradation of PNP was further analyzed by using UV-vis, FTIR and GC/MS, and the results suggest that Fe/Cu bimetallic system with air aeration could completely break the benzene ring and NO2 structure of PNP and could generate the nontoxic and biodegradable intermediate products. Meanwhile, most of these intermediate products were further mineralized into CO2 and H2O, which brought about a high COD removal efficiency (83.8%). Therefore, Fe/Cu bimetallic system with air aeration would be a promising process for toxic refractory industry wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

Science.gov (United States)

Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

2015-03-01

Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

NMR and NQR study of the electronic and structural properties of Al-Cu-Fe and Al-Cu-Ru quasicrystals

International Nuclear Information System (INIS)

Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I.

1994-01-01

27 Al and 63,65 Cu NMR is reported for powdered stable Al-Cu-Fe and Al-Cu-Ru icosahedral quasicrystals and crystalline approximants, and for an Al-Pd-Mn single-grain quasicrystal. 27 Al NQR spectra at 4.2 K were observed in Al-Cu-Fe and Al-Cu-Ru samples. From quadrupole-perturbed NMR spectra at different magnetic fields, and from zero-field NQR spectra, a wide distribution of local electric-field gradient (EFG) tensor components and principal-axis-system orientations was found at the Al site. A model EFG calculation based on a 1/1 Al-Cu-Fe approximant successfully explained the observed NQR spectra. The average local gradient is largely determined by the p-electron wave function at the Al site, while the width of the distribution is due to EFG lattice contribution. Comparison of 63 Cu and 27 Al NMR shows the EFG distribution at the two sites is similar, but the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more s-type wave function of the conduction electrons. Overall spread of EFG values is well reproduced by calculation based on the approximant. However, the experimental spectra indicate a much larger number of nonequivalent sites when compared with the simulated NQR spectra based on the 1/1 approximant. The short-range, local chemical order is well represented by the approximant, but differences in coordination must be included at intermediate range in the quasicrystal. Measured 27 Al Knight shift, magnetic susceptibility, and nuclear spin-lattice relaxation time as a function of temperature indicate reduced density of states at the Fermi level by a factor of 7 or 8 from the value in Al metal, consistent with the notion of a pseudogap for these quasicrystals. No differences in measured parameters were detected as a function of composition of the quasicrystalline alloys

Fabrication of Fe{sub 3}O{sub 4}@CuO core-shell from MOF based materials and its antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Rajabi, S.K. [Department of Chemistry, University of Guilan, University Campus 2, Rasht (Iran, Islamic Republic of); Sohrabnezhad, Sh., E-mail: sohrabnezhad@guilan.ac.ir [Department of Chemistry, Faculty of Science, University of Guilan, P.O. Box 1914, Rasht (Iran, Islamic Republic of); Ghafourian, S. [Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam (Iran, Islamic Republic of)

2016-12-15

Magnetic Fe{sub 3}O{sub 4}@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe{sub 3}O{sub 4}@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe{sub 3}O{sub 4} core and a CuO shell. The Fe{sub 3}O{sub 4}@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe{sub 3}O{sub 4}-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent. - Graphical abstract: Fe{sub 3}O{sub 4}@CuO core-shell release of copper ions. These Cu{sup 2+} ions were responsible for the exhibited antibacterial activity. - Highlights: • The Fe{sub 3}O{sub 4}@CuO core-shell was prepared by MOF method. • This is the first study of antibacterial activity of core-shell consist of CuO and Fe{sub 3}O{sub 4}. • The core-shell can be reused effectively. • Core-shell was separated from the reaction solution by external magnetic field.

Reducing the ordering temperature of FePt nanoparticles by Cu additive and alternate reduction method

Directory of Open Access Journals (Sweden)

Fang Wang

2017-12-01

Full Text Available (FePt85Cu15 nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium. Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature. Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature. It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.

Thermal stability of Py/Cu and Co/Cu giant magnetoresistance (GMR) multilayer systems

Energy Technology Data Exchange (ETDEWEB)

Vovk, Vitaliy

2007-07-01

NiFe/Cu and Co/Cu multilayer systems have been studied regarding the mechanisms of thermal degradation of the giant magnetoresistance effect (GMR). The different thermodynamics of the studied systems results in different mechanisms of the GMR degradation as shown by highest resolution nanoanalysis using the three dimensional wide angle tomographic atom probe. According to the TAP analysis, GMR deterioration in Py/Cu system occurs due to the broadening of the layer interfaces observed at 250 C. In contrast, due to the strong demixing tendency, Co/Cu multilayers remain stable up to 450 C. At higher temperatures ferromagnetic bridging of the neighboring Co layers takes place leading to the GMR breakdown. In both Py/Cu and Co/Cu systems recrystallization is induced at 350-450 C, which is accompanied by a change in the crystallographic orientation from <111> to <100> wire texture. The reaction may be utilized to produce GMR sensor layers of remarkable thermal stability. Although the systems of interest are equivalent in respect of the observed phenomenon, the Ni{sub x}Fe{sub 1-x}/Cu system is chosen for a detailed analysis because it allows a precise control of the lattice constant by varying the Fe content in the Ni{sub x}Fe{sub 1-x} layer. It is shown that the crystallographic reorientation is triggered by the minimization of lattice mismatch elastic energy. Moreover, the counteraction between the elastic and interfacial energy minimizations exerts a critical influence on the recrystallization probability. (orig.)

Enhanced photocatalytic, electrochemical and photoelectrochemical properties of TiO{sub 2} nanotubes arrays modified with Cu, AgCu and Bi nanoparticles obtained via radiolytic reduction

Energy Technology Data Exchange (ETDEWEB)

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

2016-11-30

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

Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

Science.gov (United States)

Rajabi, S. K.; Sohrabnezhad, Sh.; Ghafourian, S.

2016-12-01

Magnetic Fe3O4@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe3O4@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe3O4 core and a CuO shell. The Fe3O4@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe3O4-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.

Coating magnetic CuFe2O4 nanoparticles with OMS-2 for enhanced degradation of organic pollutants via peroxymonosulfate activation

Science.gov (United States)

Ye, Peng; Wu, Deming; Wang, Manye; Wei, Yi; Xu, Aihua; Li, Xiaoxia

2018-01-01

A heterogeneous magnetic CuFe2O4@OMS-2 catalyst was fabricated through a facile solvent-free process using Mn(CH3COO)2 and KMnO4 in the presence of CuFe2O4. It was found that the BET surface area of OMS-2 as well as the ratio of low-valent manganese species significantly increased in the hybrid catalyst, due to interactions between CuFe2O4 and the precursor of amorphous manganese oxide. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the CuFe2O4@OMS-2 catalyst within 30 min in the presence of peroxymonosulfate (PMS), while CuFe2O4 and OMS-2 showed no significant activity for the reaction. The hybrid catalyst also exhibited excellent long-term stability and could be easily recovered with the assistance of an external magnetic field. A possible degradation mechanism for the synergistic effects of different valent metal species and reactive radicals was proposed, which involved the electron transfer from Mn(III) or Mn(II) species to PMS with the generation of sulfate and hydroxyl radicals, and from AO7 and Cu(I) in CuFe2O4 to Mn(IV) and Mn(III) to reduce these Mn species.

Chelation of Cu(II, Zn(II, and Fe(II by Tannin Constituents of Selected Edible Nuts

Directory of Open Access Journals (Sweden)

Magdalena Karamać

2009-12-01

Full Text Available The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II and Zn(II was determined by the reaction with tetramethylmurexide, whereas for Fe(II, ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II. The Fe(II complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II by ~90%. The capacity to chelate Zn(II was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II, whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II chelation took place at the levels tested.

Heteropoly acid promoted Cu and Fe catalysts for the selective catalytic reduction of NO with ammonia

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Mossin, Susanne L.; Riisager, Anders

2011-01-01

Cu/TiO2, Fe/TiO2 and heteropoly acid promoted Cu/TiO2, Fe/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD, NH3-TPD, H2-TPR and EPR. The catalysts exhibited only crystalline TiO2 phases with the active metals and promoters in highly dispersed state. The acidic properties...... activity and acidity was lower for promoted catalysts than for unpromoted catalysts. In the heteropoly acid promoted catalysts the SCR active Cu and Fe metals were protected from potassium poisons by bonding of the potassium to the Brønsted acid centres. Thus heteropoly acid promoted catalysts might...... be suitable for biomass fired power plant SCR applications....

Synthesis and Characterization of High-Entropy Alloy AlFeCoNiCuCr by Laser Cladding

Directory of Open Access Journals (Sweden)

Xiaoyang Ye

2011-01-01

Full Text Available High-entropy alloys have been recently found to have novel microstructures and unique properties. In this study, a novel AlFeCoNiCuCr high-entropy alloy was prepared by laser cladding. The microstructure, chemical composition, and constituent phases of the synthesized alloy were characterized by SEM, EDS, XRD, and TEM, respectively. High-temperature hardness was also evaluated. Experimental results demonstrate that the AlFeCoNiCuCr clad layer is composed of only BCC and FCC phases. The clad layers exhibit higher hardness at higher Al atomic content. The AlFeCoNiCuCr clad layer exhibits increased hardness at temperature between 400–700°C.

Nitrogen adsorption on Fe(111), (100), and (110) surfaces

DEFF Research Database (Denmark)

Mortensen, Jens Jørgen; Ganduglia-Pirovano, Veronica; Hansen, Lars Bruno

1999-01-01

Adsorption energies and structures for N atoms on three low-index surfaces of Fe have been calculated using density functional theory (DFT) and the generalized gradient approximation (GGA). At low N coverage the adsorption energy on Fe(100) is found to be similar to 0.7 eV higher than on the (111......) and (110) surfaces - particularly the c(2 x 2)-N/Fe(100) structure with the N atoms in four-fold sites is very stable. We attribute the differences in adsorption energy to the lack of four-fold sites on the (111) and (110) surfaces, We suggest that at higher N coverages, islands with a structure similar...

Structure of as cast L12 compounds in Al3Zr-base alloys containing Cu and Mn

International Nuclear Information System (INIS)

Virk, I.S.; Varin, R.A.

1991-01-01

It was first shown that the low symmetry, tetragonal DO 23 crystal structure of Al 3 Zr intermetallic can be changed to the related cubic L1 2 crystal structure by alloying with Ni (Al 5 NiZr 2 ) and Cu(Al 5 CuZr 2 ). It has been reported that previous work has successfully modified Al 3 Zr with Fe, Cu, Cr and Ni obtaining nearly single phase materials with L1 2 structure. However, they only studied the microstructure and mechanical properties of Fe - modified intermetallic (Al-6at% Fe-25at% Zr). The purpose of the paper is to describe and interpret experimental observations on the microstructure of Al 5 CuZr 2 and Al 66 Mn 9 Zr 25 (at.%) modifications of base Al 3 Zr intermetallic. The one modified with Mn has not been reported in literature although its Al 3 Ti - base counterpart has recently been successfully produced (3, 4)

Study of the ternary alloy systems Al-Ni-Fe and Al-Cu-Ru with special regard to quasicrystalline phases

International Nuclear Information System (INIS)

Lemmerz, U.

1996-07-01

Two ternary alloy-systems, the Al-Ni-Fe system and the Al-Cu-Ru system were studied with special regard to quasicrystalline phases. Isothermal sections were established in both systems in the stoichiometric area of the quasicrystalline phase. In the Al-Ni-Fe system a new stable decagonal phase was found. Its stoichiometric range is very small around Al 71.6 Ni 23.0 Fe 5.4 . The temperature range in which it is stable lies between 847 and 930 C. The decagonal phase undergoes a eutectoid reaction to the three crystalline phases Al 3 Ni 2 , Al 3 Ni and Al 13 Fe 4 at 847 C. It melts peritectically at 930 C forming Al 13 Fe 4 , Al 3 Ni 2 and a liquid. The investigations in the Al-Cu-Ru system concentrated on the phase equilibria between the icosahedral phase and its neighbouring phases in a temperature range between 600 and 1000 C. The icosahedral phase was observed in the whole temperature range. The investigated stoichiometric area extends down to Al contents of 45%, which allows the fields of existence to be determined for the ternary phases α-AlCuRu, the icosahedral phase and Al 7 Cu 2 Ru. Binary phases were determined down to the upper (high Al content) border of AlRu. No hitherto unknown phase was observed in the investigated area. Rietveld analyses were carried out on α-AlCuRu and Al 7 Cu 2 Ru showing some discrepancies from the α-AlMnSi structure taken as a base for α-AlCuRu and confirming the Al 7 Cu 2 Fe structure for Al 7 Cu 2 Ru. (orig.)

Distribution of Ca, Fe, Cu and Zn in primary colorectal cancer and secondary colorectal liver metastases

International Nuclear Information System (INIS)

Al-Ebraheem, A.; Mersov, A.; Gurusamy, K.; Farquharson, M.J.

2010-01-01

A microbeam synchrotron X-ray fluorescence (μSRXRF) technique has been used to determine the localization and the relative concentrations of Zn, Cu, Fe and Ca in primary colorectal cancer and secondary colorectal liver metastases. 24 colon and 23 liver samples were examined, all of which were formalin fixed tissues arranged as microarrays of 1.0 mm diameter and 10 μm thickness. The distribution of these metals was compared with light transmission images of adjacent sections that were H and E stained to reveal the location of the cancer cells. Histological details were provided for each sample which enable concentrations of all elements in different tissue types to be compared. In the case of liver, significant differences have been found for all elements when comparing tumour, normal, necrotic, fibrotic, and blood vessel tissues (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have also been found to be significantly different among tumour, necrotic, fibrotic, and mucin tissues in the colon samples (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have been compared between primary colorectal samples and colorectal liver metastases. Concentration of Zn, Cu, Fe and Ca are higher in all types of liver tissues compared to those in the colon tissues. Comparing liver tumour and colon tumour samples, significant differences have been found for all elements (Mann Whitney, P<0.0001). For necrotic tissues, significant increase has been found for Zn, Ca, Cu and Fe (Mann Whitney, P<0.0001 for Fe and Zn, 0.014 for Ca, and 0.001 for Cu). The liver fibrotic levels of Zn, Ca, Cu and Fe were higher than the fibrotic colon areas (independent T test, P=0.007 for Zn and Mann Whitney test P<0.0001 for Cu, Fe and Ca). For the blood vessel tissue, the analysis revealed that the difference was only significant for Fe (P=0.009) from independent T test.

Role of heat on the development of electrochemical sensors on bare and modified Co3O4/CuO composite nanopowder carbon paste electrodes.

Science.gov (United States)

Kumar, Mohan; Kumara Swamy, B E

2016-01-01

The Co3O4/CuO composite nanopowder (NP) was synthesized by a mechanochemical method and characterized by using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The synthesized Co3O4/CuO NP was used as a modified carbon paste electrode (MCPE) and further the bare carbon paste and Co3O4/CuO NP modified carbon paste was heated at different temperatures (100, 150, 200 and 250 °C) for 10 min. The Co3O4/CuO NP MCPE was used to study the consequences of scan rate and dopamine concentration. Furthermore the preheated modified electrodes were used to study the electrochemical response to dopamine (DA), ascorbic acid (AA) and uric acid (UA). Copyright © 2015 Elsevier B.V. All rights reserved.

On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

Directory of Open Access Journals (Sweden)

Anna M. Manzoni

2016-03-01

Full Text Available The most commonly investigated high entropy alloy, AlCoCrCuFeNi, has been chosen for optimization of its microstructural and mechanical properties by means of compositional changes and heat treatments. Among the different available optimization paths, the decrease of segregating element Cu, the increase of oxidation protective elements Al and Cr and the approach towards a γ-γ′ microstructure like in Ni-based superalloys have been probed and compared. Microscopical observations have been made for every optimization step. Vickers microhardness measurements and/or tensile/compression test have been carried out when the alloy was appropriate. Five derived alloys AlCoCrFeNi, Al23Co15Cr23Cu8Fe15Ni16, Al8Co17Cr17Cu8Fe17Ni33, Al8Co17Cr14Cu8Fe17Ni34.8Mo0.1Ti1W0.1 and Al10Co25Cr8Fe15Ni36Ti6 (all at.% have been compared to the original AlCoCrCuFeNi and the most promising one has been selected for further investigation.

Artificial intelligence applied to atomistic kinetic Monte Carlo simulations in Fe-Cu alloys

International Nuclear Information System (INIS)

Djurabekova, F.G.; Domingos, R.; Cerchiara, G.; Castin, N.; Vincent, E.; Malerba, L.

2007-01-01

Vacancy migration energies as functions of the local atomic configuration (LAC) in Fe-Cu alloys have been systematically tabulated using an appropriate interatomic potential for the alloy of interest. Subsets of these tabulations have been used to train an artificial neural network (ANN) to predict all vacancy migration energies depending on the LAC. The error in the prediction of the ANN has been evaluated by a fuzzy logic system (FLS), allowing a feedback to be introduced for further training, to improve the ANN prediction. This artificial intelligence (AI) system is used to develop a novel approach to atomistic kinetic Monte Carlo (AKMC) simulations, aimed at providing a better description of the kinetic path followed by the system through diffusion of solute atoms in the alloy via vacancy mechanism. Fe-Cu has been chosen because of the importance of Cu precipitation in Fe in connection with the embrittlement of reactor pressure vessels of existing nuclear power plants. In this paper the method is described in some detail and the first results of its application are presented and briefly discussed

Artificial intelligence applied to atomistic kinetic Monte Carlo simulations in Fe-Cu alloys

Energy Technology Data Exchange (ETDEWEB)

Djurabekova, F.G. [Reactor Materials Research Unit, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Domingos, R. [Reactor Materials Research Unit, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Cerchiara, G. [Department of Nuclear and Production Engineering, University of Pisa (Italy); Castin, N. [Catholic University of Louvain-la-Neuve (Belgium); Vincent, E. [LMPGM UMR-8517, University of Lille I, Villeneuve d' Ascq (France); Malerba, L. [Reactor Materials Research Unit, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)]. E-mail: lmalerba@sckcen.be

2007-02-15

Vacancy migration energies as functions of the local atomic configuration (LAC) in Fe-Cu alloys have been systematically tabulated using an appropriate interatomic potential for the alloy of interest. Subsets of these tabulations have been used to train an artificial neural network (ANN) to predict all vacancy migration energies depending on the LAC. The error in the prediction of the ANN has been evaluated by a fuzzy logic system (FLS), allowing a feedback to be introduced for further training, to improve the ANN prediction. This artificial intelligence (AI) system is used to develop a novel approach to atomistic kinetic Monte Carlo (AKMC) simulations, aimed at providing a better description of the kinetic path followed by the system through diffusion of solute atoms in the alloy via vacancy mechanism. Fe-Cu has been chosen because of the importance of Cu precipitation in Fe in connection with the embrittlement of reactor pressure vessels of existing nuclear power plants. In this paper the method is described in some detail and the first results of its application are presented and briefly discussed.

Investigation of the solubility and diffusion of Fe atoms in Cu at high temperature using molten salt electrochemistry

International Nuclear Information System (INIS)

Wenzl, H.; Sorajic, V.; Bischof, B.

1977-01-01

The electrochemical cell CuFesub(n)/KF, LiF, FeF 2 (molten solution)/Fe was used between 800 and 1,000 0 C to produce CuFesub(n) alloys of various copper rich compositions n by electrochemically controlled diffusion. From measurements of cell voltage and current we determined composition, bulk diffusion coefficient D, and atomic solubility limit x 0 of Fe in Cu. The numerical values at the temperature of 950 0 C are D = 0.9 x 10 -9 cm 2 /sec, x 0 = 1.2 at%. (orig.) [de

Anomalous fast diffusion in Cu-NiFe nanolaminates.

Energy Technology Data Exchange (ETDEWEB)

Jankowski, Alan F. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States). Energy Nanomaterials Dept.

2017-09-01

For this work, the decomposition of the one-dimensional composition wave in Cu-NiFe nanolaminate structures is examined using x-ray diffraction to assess the kinetics of phase decomposition. The anomalously high diffusivity value found for long-term aging at room temperature is attributed to the inherent nanostructure that features paths for short-circuit diffusion in nanolaminates as attributed to interlayer grain boundaries.

Copper separation using modified active carbon before the polarographic determination of Pb, Cd, Ni, Zn and Fe in wastes

International Nuclear Information System (INIS)

Rubel, S.; Lada, Z.M.; Golimowski, J.

1977-01-01

The investigations on the selective separation of Pb 2+ , Cd 2+ , Ni 2+ , Zn 2+ and Fe 3+ ions from the excess of copper were carried out. For this purpose active carbon modified by Na-diethyldithiocarbamate was used. The manner of DDTK-Na deposition on active carbon has been elaborated. The influence of pH was investigated and it was found that at pH 1(HNO 3 ) copper ions are quantitavely bound on modified carbon whereas other ions (Pb 2+ , Cd 2+ , Ni 2+ , Zn 2+ and Fe 3+ ) remain in the solution and can be determined polarographically. The elaborated method was applied to the determination of mentioned ions in the samples of wastes containing even 100-fold excess of copper. The concentration of copper can not exceed 100 mg/dm 3 . (author)

Study of CuAl(100) by using He ion scattering

Energy Technology Data Exchange (ETDEWEB)

Zhu, L; Zur Muhlen, E; O` Connor, D J [Newcastle Univ., NSW (Australia). Dept. of Physics

1994-12-31

The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.

Study of CuAl(100) by using He ion scattering

Energy Technology Data Exchange (ETDEWEB)

Zhu, L.; Zur Muhlen, E.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

1993-12-31

The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.

Structure and frictional properties of Langmuir-Blodgett films of Cu nanoparticles modified by dialkyldithiophosphate

International Nuclear Information System (INIS)

Xu Jun; Dai Shuxi; Cheng Gang; Jiang Xiaohong; Tao Xiaojun; Zhang Pingyu; Du Zuliang

2006-01-01

Langmuir-Blodgett (LB) films of dialkyldithiophosphate (DDP) modified Cu nanoparticles were prepared. The structure, microfrictional behaviors and adhesion of the LB films were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and atomic/friction force microscopy (AFM/FFM). Our results showed that the modified Cu nanoparticles have a typical core-shell structure and fine film-forming ability. The images of AFM/FFM showed that LB films of modified Cu nanoparticles were composed of many nanoparticles arranged closely and orderly and the nanoparticles had favorable behaviors of lower friction. The friction loop of the films indicated that the friction force was affected prominently by the surface slope of the Cu nanoparticles and the microfrictional behaviors showed obvious 'ratchet effect'. The adhesion experiment showed that the modified Cu nanoparticle had a very small adhesive force

Attenuation curves in concrete of neutrons from 100 to 400 MeV per nucleon He, C, Ne, Ar, Fe and Xe ions on various targets

Energy Technology Data Exchange (ETDEWEB)

Agosteo, S.; Nakamura, T.; Silari, M. E-mail: marco.silari@cern.ch; Zajacova, Z

2004-04-01

Data on transmission of neutrons in concrete generated by heavy ions of intermediate energies (of typically up to 1 GeV per nucleon) are of interest for shielding design of accelerators for use in both the research and in the medical field. The energy distributions of neutrons produced by ions of different species (from He to Xe) striking various targets at energies from 100 to 800 MeV per nucleon were recently measured by Kurosawa et al. in the angular range 0-90 deg. . These spectra were used as input data for Monte Carlo simulations to determine source terms and attenuation lengths in ordinary concrete. The present paper presents calculations for 100 MeV/u helium ions on a Cu target, 100 MeV/u carbon ions on C, Al, Cu and Pb, 100 MeV/u neon ions on Cu and Pb, 400 MeV/u carbon ions on C, Al, Cu and Pb, 400 MeV/u neon ions on Cu, 400 MeV/u Ar ions on Cu, 400 MeV/u Fe ions on Cu and 400 MeV/u Xe ions on Cu. The results include the contributions of all secondaries. Some of the resulting attenuation curves are best fitted by a double-exponential function rather than the usual single-exponential. The effect of various approximations introduced in the simulations is discussed. A comparison is made with shielding data for protons scaled with the ion mass number. A comparison is also made with a simple analytical model in use at GANIL.

Chemical synthesis of flower-like hybrid Cu(OH)2/CuO electrode: Application of polyvinyl alcohol and triton X-100 to enhance supercapacitor performance.

Science.gov (United States)

Shinde, S K; Fulari, V J; Kim, D-Y; Maile, N C; Koli, R R; Dhaygude, H D; Ghodake, G S

2017-08-01

In this research article, we report hybrid nanomaterials of copper hydroxide/copper oxide (Cu(OH) 2 /CuO). A thin films were prepared by using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method. As-synthesized and hybrid Cu(OH) 2 /CuO with two different surfactants polyvinyl alcohol (PVA) and triton-X 100 (TRX-100) was prepared having distinct morphological, structural, and supercapacitor properties. The surface of the thin film samples were examined by scanning electron microscopy (SEM). A nanoflower-like morphology of the Cu(OH) 2 /CuO nanostructures arranged vertically was evidenced on the stainless steel substrate. The surface was well covered by nanoflake-like morphology and formed a uniform Cu(OH) 2 /CuO nanostructures after treating with surfactants. X-ray diffraction patterns were used to confirm the hybrid phase of Cu(OH) 2 /CuO materials. The electrochemical properties of the pristine Cu(OH) 2 /CuO, PVA:Cu(OH) 2 /CuO, TRX-100:Cu(OH) 2 /CuO films were observed by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy technique. The electrochemical examination reveals that the Cu(OH) 2 /CuO electrode has excellent specific capacitance, 292, 533, and 443Fg -1 with pristine, PVA, and TRX-100, respectively in 1M Na 2 SO 4 electrolyte solution. The cyclic voltammograms (CV) of Cu(OH) 2 /CuO electrode shows positive role of the PVA and TRX-100 to enhance supercapacitor performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication of magnetically recyclable Fe{sub 3}O{sub 4}@Cu nanocomposites with high catalytic performance for the reduction of organic dyes and 4-nitrophenol

Energy Technology Data Exchange (ETDEWEB)

Tang, Mingyi, E-mail: mingyitjucu@163.com [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Zhang, Sai; Li, Xianxian; Pang, Xiaobo [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia [School of Science, Tianjin University, Tianjin 300072 (China)

2014-12-15

A facile and efficient approach to synthesize Fe{sub 3}O{sub 4}@Cu nanocomposites using L-Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe{sub 3}O{sub 4}@Cu nanocomposites were characterized by Fourier Transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. In addition, the magnetic properties were determined with vibrating sample magnetometer. The surface of the Fe{sub 3}O{sub 4} contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe{sub 3}O{sub 4}@Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe{sub 3}O{sub 4}@Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe{sub 3}O{sub 4}@Cu nanocomposites are more efficient catalysts compared with Cu nanoparticles and can easily be recovered from the reaction mixture with magnet. The cost effective and recyclable Fe{sub 3}O{sub 4}@Cu nanocomposites provide an exciting new material for environmental protection applications. - Highlights: • Cu nanoparticles as small as 3 nm are synthesized. • Low cost Fe{sub 3}O{sub 4}@Cu magnetical nanoparticles show catalytic activity for organic dyes and 4-nitrophenol. • The Fe{sub 3}O{sub 4}@Cu display high catalytic activity after 13 cycles.

Estimation of (Cl-Mn) /Fe flux ratio at relativistic energies using steady-state leaky-box model modified for re accelerations

International Nuclear Information System (INIS)

Majumdar, R.; Basu, B.; Bhattacharyya, D.P.

1997-01-01

The (Cl-Mn) /Fe flux ratio at the top of the atmosphere has been estimated from source composition. The authors have adopted the SSLB model modified for weak shocks to estimate the enhancement of (Cl-Mn) /Fe flux ratio due to re acceleration. The observed active detector results of Lezniak and Webber, Caldwell, Orth et al., Engelmann et al., and our passive detector results are fairly supported by the expected results from the SSLB model modified with re acceleration after Ferrando for energies ≤ 100 GeV / n

Modified Fe3O4- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

Science.gov (United States)

Valizadeh, S.; Rasoulifard, M. H.; Dorraji, M. S. Seyed

2014-11-01

The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag3PO4 formation. Apparent reaction rate constant (Kapp) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H2O2, Co-M-HAP(II)/H2O2 and M-HAP (I)/UV systems, respectively.

Oxygen formation in gamma-ray irradiation of Fe2+ -Cu2+ solutions

DEFF Research Database (Denmark)

Bjergbakke, Erling; Hart, E.J.

1971-01-01

value diminishes slightly and is displaced toward higher ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratios with increasing acidity. The perchlorate system differs from the sulfate only at high ${\\rm Cu}({\\rm ClO}_{4})/{\\rm Fe}({\\rm ClO}_{4})_{2}$ ratios where $G({\\rm O}_{2})$ rises to 0.10. The O2 yield of 0.......02 is not derived from "spur" HO2, OH, H2 O2 or O2, although the increase in $G({\\rm O}_{2})$ above this level in the perchlorate system is attributed to H2 O2. "Spur" O atoms are postulated as the source of O2 with the yield, $G({\\rm O}_{2})$ = 0.02....

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

African Journals Online (AJOL)

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd and Pb) in the soft tissues of the gastropods Tympanotonus fuscatus fuscatus and Tf radula collected in the Ebrié Lagoon (Côte d'Ivoire): Evidence of the risks linked to linked to lead and.

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...

Effects of interfacial transition layers on the electrical properties of individual Fe 30 Co 61 Cu 9 /Cu multilayer nanowires

KAUST Repository

Ma, Hongbin; Zhang, Junwei; Zhang, Hong; Lan, Qianqian; Guan, Chaoshuai; Zhang, Qiang; Bai, Feiming; Peng, Yong; Zhang, Xixiang

2016-01-01

to those of individual pure Cu nanowires and to those of alloy Fe30Co61Cu9 nanowires. The multilayered nanowires with a 50 nm diameter had a remarkable resistivity of approximately 5.41 × 10-7 Ω m and a failure current density of 1.54 × 1011 A m-2. Detailed

A GREENER SYNTHESIS OF CORE (FE, CU)-SHELL (AU, PT, PD AND AG) NANOCRYSTALS USING AQUEOUS VITAMIN C

Science.gov (United States)

A greener method to fabricate the novel core (Fe and Cu)-shell (noble metals) metal nanocrystals using aqueous ascorbic acid (vitamin C) is described. Transition metal salts such as Cu and Fe were reduced using ascorbic acid, a benign naturally available antioxidant, and then add...

Mineralization of phthalic acid by solar photoelectro-Fenton with a stirred boron-doped diamond/air-diffusion tank reactor: Influence of Fe3+ and Cu2+ catalysts and identification of oxidation products

International Nuclear Information System (INIS)

Garcia-Segura, Sergi; Salazar, Ricardo; Brillas, Enric

2013-01-01

Highlights: • Almost total mineralization of phthalic acid by solar photoelectro-Fenton with Fe 3+ , Cu 2+ and Fe 3+ –Cu 2+ mixtures. • Hydroxyl radical generation from photo-Fenton reaction under solar radiation. • Enhancement of the mineralization rate using Fe 3+ and small amounts of Cu 2+ . • Detection of eleven aromatic intermediates and six short-linear carboxylic acids. • Oxidation of Cu(II)-carboxylate complexes with ·OH and photolysis of Fe(III)-carboxylate species. -- Abstract: Here, the substrate decay and mineralization rate for 100 cm 3 of a 2.0 mM phthalic acid solution in 0.10 M Na 2 SO 4 of pH 3.0 have been studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). The electrochemical cell was a stirred tank reactor containing a 3 cm 2 boron-doped diamond (BDD) anode and a 3 cm 2 air-diffusion cathode that generates H 2 O 2 . Cu 2+ and/or Fe 3+ were added as catalysts with total concentration of 0.50 mM and a constant current density of 33.3 mA cm −2 was applied. In EF with Cu 2+ or Fe 3+ alone and SPEF with only Cu 2+ , phthalic acid decayed slowly and poor mineralization was reached because the main oxidant was ·OH produced at the BDD surface from water oxidation. In contrast, the substrate destruction was largely enhanced using SPEF with 0.50 mM Fe 3+ since a high quantity of oxidant ·OH was produced in the bulk induced by photo-Fenton reaction. This treatment led to an almost total mineralization by the photolysis of generated Fe(III)-carboxylate complexes. In all cases, the decay of phthalic acid obeyed a pseudo-first-order reaction. The combination of Cu 2+ and Fe 3+ as catalysts accelerated the mineralization process in SPEF because Cu(II)-carboxylate complexes were also removed with ·OH formed from photo-Fenton reaction. The best SPEF process was found for 0.125 mM Cu 2+ + 0.375 mM Fe 3+ , giving rise to 99% mineralization with 40% current efficiency and 0.294 kWh g −1 TOC energy consumption. Eleven aromatics

A novel lithium copper iron phosphate with idealized formula Li5Cu22+Fe3+(PO44: crystal structure and distribution of defects

Directory of Open Access Journals (Sweden)

Shailesh Upreti

2011-05-01

Full Text Available Gray–green single crystals were obtained under high-pressure, high-temperature hydrothermal conditions. A refinement of atom occupancies gave the composition Li3.68Cu2+Fe3+(Cu0.55Li0.452Fe2+0.15(PO44. The structure is built from triplets of edge-sharing (Cu,LiO5–FeO6–(Cu,LiO5 polyhedra, CuO4 quadrilaterals and PO4 tetrahedra. In the (Cu,LiO5 polyhedra the Cu and Li positions are statistically occupied in a 0.551 (2:0.449 (2 ratio. Both FeO6 and CuO4 polyhedra exhibit overline1 symmetry. The positions of additional Li atoms with vacancy defects are in the interstices of the framework.

Magnetic properties and EXAFS study of nanocrystalline Fe2Mn0.5Cu0.5Al synthesized using mechanical alloying technique

International Nuclear Information System (INIS)

Nanto, Dwi; Yang, Dong-Seok; Yu, Seong-Cho

2014-01-01

Nanocrystalline Fe 2 Mn 0.5 Cu 0.5 Al has been synthesized by the mechanical alloying technique and studied as a function of milling time. Alloy nature of Fe 2 Mn 0.5 Cu 0.5 Al was observed in a sample milled for 96 h. The magnetic saturation is 4.0 μ B /f.u., which coincidently follows Slater–Pauling rule at 5 K. Nanocrystalline Fe 2 Mn 0.5 Cu 0.5 Al has enhanced saturate magnetization compared to any other fabrication of Fe 2 MnAl reported. Cu element plays an important role in site competes with other elements and may result in the enhancement of saturate magnetization. In accordance to the magnetic results and EXAFS pattern, it was revealed that the dynamics of magnetic properties were confirmed as structural changes of nanocrystalline Fe 2 Mn 0.5 Cu 0.5 Al

Frustrated magnetization in PrxLa1-xBaCuO5Fe

International Nuclear Information System (INIS)

Ortiz, W.A.; Araujo-Moreira, F.M.; Prassides, K.

1999-01-01

The crystal structure of the system Pr x La 1-x BaCuO 5 Fe has been recently reviewed. The magnetic structure of samples with x = 0 and x = 1 is mainly due to effective local moments of iron and copper. In Pr-rich samples, Fe ions occupy two non-equivalent positions, making it substantially plausible that two or more magnetic subsets might coexist in the system. This contribution presents magnetization studies on five samples of the Pr x La 1-x BaCuO 5 Fe system (x = 0.0, 0.2, 0.5, 0.7 and 1.0). All samples exhibit a strong irreversible behavior between zero-field-cooled and field-cooled procedures below a certain irreversibility temperature T i . Above T i , both branches are coincident and well described by a Curie-Weiss fitting. Decreasing the temperature below T i , the zero-field-cooled response increases less than the field-cooled curve, indicating some degree of frustrated antiferromagnetic couplings. (orig.)

Synthesis of MIL-100(Fe at Low Temperature and Atmospheric Pressure

Directory of Open Access Journals (Sweden)

Jing Shi

2013-01-01

Full Text Available MIL-100(Fe, a mesoporous metal-organic framework (MOF, has a large BET specific surface area and pore volume with the presence of a significant amount of accessible Lewis acid metal sites upon dehydration. The structural characteristics of MIL-100(Fe make it a good candidate for potential applications in gas storage, separation, and heterogeneous catalysis. Mainly, this MOF is obtained by the hydrothermal synthesis in a Teflon-lined autoclave at high temperature (>150°C under static conditions. However, this method has several disadvantages such as high temperature, high (autogenous pressure, long time, and comparable low MOF yield. Therefore, development of a facile method for synthesis of MIL-100(Fe is vitally important for fundamental understanding and practical application. Herein, MIL-100(Fe is synthesized by a facile low-temperature (90% still could be achieved, suggesting that this simple and energy saving method has the potential to be used practically.

Structural features in icosahedral Al63Cu25Fe12

International Nuclear Information System (INIS)

Howell, R.H.; Solal, F.; Turchi, P.E.A.; Berger, C.; Calvayrac, Y.

1991-01-01

Since the discovery of a quasicrystalline phase in Al-Mn alloys a substantial amount of work has been done to understand the structural and physical properties of this new class of materials. More recently the discovery of a thermodynamically stable icosahedral phase in AlCuFe presents the opportunity to study pure quasicrystalline phases of high structural quality by eliminating known defects, especially phason disorder by conventional heat treatment. In particular it was shown that annealing treatments of as quenched samples resulted in a dramatic reduction in the width of the diffraction peaks associated with the elimination of as quenched defects, present in other quasicrystals. Positron annihilation lifetime measurements have a high sensitivity to intrinsic defects and positron annihilation radiation angular correlation measurements are well suited to measurements of electronic structure in systems where the defect effects do not dominate. We have measured positron annihilation lifetime and angular correlations on quasicrystalline samples of Al 63 Cu 25 Fe 12 in the pure icosahedral phase

In-situ EC-STM studies on the influence of halide anions on structure and reactivity of dibenzylviologen on Cu(100)

Energy Technology Data Exchange (ETDEWEB)

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

2009-07-01

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

46 CFR 53.01-5 - Scope (modifies HG-100).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5... General Requirements § 53.01-5 Scope (modifies HG-100). (a) The regulations in this part apply to steam... governing various types of pressure vessels and boilers. (b) Modifies HG-100. The requirements of Part HG of...

Multiple response optimization for Cu, Fe and Pb determination in naphtha by graphite furnace atomic absorption spectrometry with sample injection as detergent emulsion

International Nuclear Information System (INIS)

Brum, Daniel M.; Lima, Claudio F.; Robaina, Nicolle F.; Fonseca, Teresa Cristina O.; Cassella, Ricardo J.

2011-01-01

The present paper reports the optimization for Cu, Fe and Pb determination in naphtha by graphite furnace atomic absorption spectrometry (GF AAS) employing a strategy based on the injection of the samples as detergent emulsions. The method was optimized in relation to the experimental conditions for the emulsion formation and taking into account that the three analytes (Cu, Fe and Pb) should be measured in the same emulsion. The optimization was performed in a multivariate way by employing a three-variable Doehlert design and a multiple response strategy. For this purpose, the individual responses of the three analytes were combined, yielding a global response that was employed as a dependent variable. The three factors related to the optimization process were: the concentration of HNO 3 , the concentration of the emulsifier agent (Triton X-100 or Triton X-114) in aqueous solution used to emulsify the sample and the volume of solution. At optimum conditions, it was possible to obtain satisfactory results with an emulsion formed by mixing 4 mL of the samples with 1 mL of a 4.7% w/v Triton X-100 solution prepared in 10% v/v HNO 3 medium. The resulting emulsion was stable for 250 min, at least, and provided enough sensitivity to determine the three analytes in the five samples tested. A recovery test was performed to evaluate the accuracy of the optimized procedure and recovery rates, in the range of 88-105%; 94-118% and 95-120%, were verified for Cu, Fe and Pb, respectively.

Multiple response optimization for Cu, Fe and Pb determination in naphtha by graphite furnace atomic absorption spectrometry with sample injection as detergent emulsion

Energy Technology Data Exchange (ETDEWEB)

Brum, Daniel M.; Lima, Claudio F. [Departamento de Quimica, Universidade Federal de Vicosa, A. Peter Henry Rolfs s/n, Vicosa/MG, 36570-000 (Brazil); Robaina, Nicolle F. [Departamento de Quimica Analitica, Universidade Federal Fluminense, Outeiro de S.J. Batista s/n, Centro, Niteroi/RJ, 24020-141 (Brazil); Fonseca, Teresa Cristina O. [Petrobras, Cenpes/PDEDS/QM, Av. Horacio Macedo 950, Ilha do Fundao, Rio de Janeiro/RJ, 21941-915 (Brazil); Cassella, Ricardo J., E-mail: cassella@vm.uff.br [Departamento de Quimica Analitica, Universidade Federal Fluminense, Outeiro de S.J. Batista s/n, Centro, Niteroi/RJ, 24020-141 (Brazil)

2011-05-15

The present paper reports the optimization for Cu, Fe and Pb determination in naphtha by graphite furnace atomic absorption spectrometry (GF AAS) employing a strategy based on the injection of the samples as detergent emulsions. The method was optimized in relation to the experimental conditions for the emulsion formation and taking into account that the three analytes (Cu, Fe and Pb) should be measured in the same emulsion. The optimization was performed in a multivariate way by employing a three-variable Doehlert design and a multiple response strategy. For this purpose, the individual responses of the three analytes were combined, yielding a global response that was employed as a dependent variable. The three factors related to the optimization process were: the concentration of HNO{sub 3}, the concentration of the emulsifier agent (Triton X-100 or Triton X-114) in aqueous solution used to emulsify the sample and the volume of solution. At optimum conditions, it was possible to obtain satisfactory results with an emulsion formed by mixing 4 mL of the samples with 1 mL of a 4.7% w/v Triton X-100 solution prepared in 10% v/v HNO{sub 3} medium. The resulting emulsion was stable for 250 min, at least, and provided enough sensitivity to determine the three analytes in the five samples tested. A recovery test was performed to evaluate the accuracy of the optimized procedure and recovery rates, in the range of 88-105%; 94-118% and 95-120%, were verified for Cu, Fe and Pb, respectively.

Fabrication of mesoporous iron (Fe) doped copper sulfide (CuS) nanocomposite in the presence of a cationic surfactant via mild hydrothermal method for supercapacitors

Science.gov (United States)

Brown, J. William; Ramesh, P. S.; Geetha, D.

2018-02-01

We report fabrication of mesoporous Fe doped CuS nanocomposites with uniform mesoporous spherical structures via a mild hydrothermal method employing copper nitrate trihydrate (Cu (NO3).3H2O), Thiourea (Tu,Sc(NH2)2 and Iron tri nitrate (Fe(No3)3) as initial materials with cationic surfactant cetyltrimethylamoniame bromide (CTAB) as stabilizer/size controller and Ethylene glycol as solvent at 130 °C temperature. The products were characterized by XRD, SEM/EDX, TEM, FTIR and UV analysis. X-ray diffraction (XRD) spectra confirmed the Fe doped CuS nanocomposites which are crystalline in nature. EDX and XRD pattern confirmed that the product is hexagonal CuS phase. Fe doped spherical structure of CuS with grain size of 21 nm was confirmed by XRD pattern. Fe doping was identified by energy dispersive spectrometry (EDS). The Fourier-transform infrared (FTIR) spectroscopy results revealed the occurrence of active functional groups required for the reduction of copper ions. Studies showed that after a definite time relining on the chosen copper source, the obtained Fe-CuS nanocomposite shows a tendency towards self-assembly and creating mesoporous like nano and submicro structures by TEM/SAED. The achievable mechanism of producing this nanocomposite was primarily discussed. The electrochemical study confirms the pseudocapacitive nature of the CuS and Fe-CuS electrodes. The CuS and Fe-CuS electrode shows a specific capacitance of about 328.26 and 516.39 Fg-1 at a scan rate of 5 mVs-1. As the electrode in a supercapacitor, the mesoporous nanostructured Fe-CuS shows excellent capacitance characteristics.

Coercivity enhancement of NdFeB sintered magnets by low melting point Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} alloy modification

Energy Technology Data Exchange (ETDEWEB)

Liang, Liping; Ma, Tianyu, E-mail: maty@zju.edu.cn; Zhang, Pei; Jin, Jiaying; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

2014-04-15

To improve coercivity without sacrificing other magnetic performance of NdFeB sintered magnets, a low melting point Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} alloy was introduced as an intergranular additive. Magnetic properties and microstructure of the magnets with different Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} contents were studied. At the optimum addition of 3 wt%, coercivity H{sub cj} was enhanced from 12.7 to 15.2 kOe, the maximum magnetic energy product (BH){sub max} was simultaneously increased from 46.6 to 47.8 MG Oe, accompanied by a slight reduction in remanence B{sub r}. Further investigation on microstructure and grain boundary composition indicated that the enhanced H{sub cj} and (BH){sub max} could be attributed to the refined and uniform 2:14:1 phase grains, continuous grain boundaries and a (Nd,Dy){sub 2}Fe{sub 14}B hardening shell surrounding the 2:14:1 phase grains. - Highlights: • Low melting-point Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} alloy was introduced to NdFeB magnets. • The doped magnet exhibits enhanced coercivity and maximum energy product. • (Nd,Dy){sub 2}Fe{sub 14}B shell was expected to form in the surface of Nd{sub 2}Fe{sub 14}B grains. • The continuous grain boundary layer formed between neighboring Nd{sub 2}Fe{sub 14}B grains.

A comprehensive study of magnetic exchanges in the layered oxychalcogenides Sr 3 Fe 2 O 5 Cu 2 Q 2 ( Q = S, Se)

Energy Technology Data Exchange (ETDEWEB)

Lü, Minfeng; Mentré, Olivier; Gordon, Elijah E.; Whangbo, Myung-Hwan; Wattiaux, Alain; Duttine, Mathieu; Tiercelin, Nicolas; Kabbour, Houria

2017-12-01

The layered oxysulfide Sr3Fe2O5Cu2S2 was prepared, and its crystal structure and magnetic properties were characterized by synchrotron X-ray diffraction (XRD), powder neutron diffraction (PND), Mössbauer spectroscopy measurements and by density functional theory (DFT) calculations. In addition, the spin exchange interactions leading to the ordered magnetic structure of Sr3Fe2O5Cu2S2 were compared with those of its selenium analogue Sr3Fe2O5Cu2Se2. The oxysulfide Sr3Fe2O5Cu2S2 adopts a G-type antiferromagnetic (AFM) structure at a temperature in the range 485–512 K, which is comparable with the three-dimensional (3D) AFM ordering temperature, TN ≈ 490 K, found for Sr3Fe2O5Cu2Se2. Consistent with this observation, the spin exchange interactions of the magnetic (Sr3Fe2O5)2+ layers are slightly greater (but comparable) for oxysulfide than for the oxyselenide. Attempts to reduce or oxidize Sr3Fe2O5Cu2S2 using topochemical routes yield metallic Fe.

Simple and efficient synthesis of copper(II)-modified uniform magnetic Fe3O4@SiO2 core/shell microspheres for immobilization of cellulase

Science.gov (United States)

Li, Shi-Kuo; Hou, Xiao-Cheng; Huang, Fang-Zhi; Li, Chuan-Hao; Kang, Wen-Juan; Xie, An-Jian; Shen, Yu-Hua

2013-11-01

In this paper, we reported a simple and efficient protocol for preparation of Cu2+-modified magnetic Fe3O4@SiO2 core/shell microspheres for immobilization of cellulase. The uniform magnetic Fe3O4@SiO2 core/shell microspheres with a thin shell of 20 nm were synthesized through a solvothermal method followed by a sol-gel process. An amino-terminated silane coupling agent of (3-aminopropyl)triethoxysilane (APTS) was then grafted on them for capturing Cu2+ ions. The reaction process is very simple, efficient, and economical. Noticeably, the content of Cu2+ ions on the magnetic core/shell microspheres can reach 4.6 Wt%, endowing them possess as high immobilization capacity as 225.5 mg/g for cellulase. And the immobilized cellulase can be retained over 90 % on the magnetic microspheres after six cycles. Meanwhile, the magnetic microspheres decorated with Cu2+ ions show a superparamagnetic character with a high magnetic saturation of 58.5 emu/g at room temperature, suggesting conveniently and rapidly recycle the enzyme from solution. This facile, recyclable, high immobilization capacity and activity strategy may find potential applications in enzyme catalytic reactions with low cost.

Simple and efficient synthesis of copper(II)-modified uniform magnetic Fe3O4@SiO2 core/shell microspheres for immobilization of cellulase

International Nuclear Information System (INIS)

Li, Shi-Kuo; Hou, Xiao-Cheng; Huang, Fang-Zhi; Li, Chuan-Hao; Kang, Wen-Juan; Xie, An-Jian; Shen, Yu-Hua

2013-01-01

In this paper, we reported a simple and efficient protocol for preparation of Cu 2+ -modified magnetic Fe 3 O 4 @SiO 2 core/shell microspheres for immobilization of cellulase. The uniform magnetic Fe 3 O 4 @SiO 2 core/shell microspheres with a thin shell of 20 nm were synthesized through a solvothermal method followed by a sol–gel process. An amino-terminated silane coupling agent of (3-aminopropyl)triethoxysilane (APTS) was then grafted on them for capturing Cu 2+ ions. The reaction process is very simple, efficient, and economical. Noticeably, the content of Cu 2+ ions on the magnetic core/shell microspheres can reach 4.6 Wt%, endowing them possess as high immobilization capacity as 225.5 mg/g for cellulase. And the immobilized cellulase can be retained over 90 % on the magnetic microspheres after six cycles. Meanwhile, the magnetic microspheres decorated with Cu 2+ ions show a superparamagnetic character with a high magnetic saturation of 58.5 emu/g at room temperature, suggesting conveniently and rapidly recycle the enzyme from solution. This facile, recyclable, high immobilization capacity and activity strategy may find potential applications in enzyme catalytic reactions with low cost

Modified Fe3O4- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

International Nuclear Information System (INIS)

Valizadeh, S.; Rasoulifard, M.H.; Dorraji, M.S. Seyed

2014-01-01

Graphical abstract: - Highlights: • Photocatalytic degradation of dye by Ag modified HAP under visible light. • Study of Fenton like degradation of dye by transition metal ions modified HAP. • Comparison of catalytic systems according to Langmuir-Hinshelwood kinetic expression. - Abstract: The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag 3 PO 4 formation. Apparent reaction rate constant (K app ) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H 2 O 2 , Co-M-HAP(II)/H 2 O 2 and M-HAP (I)/UV systems, respectively

Determination of Ca, Fe, Cu and Zn content in hair by EDXRF method

International Nuclear Information System (INIS)

Yang Mingtai; Chen Jinhua; Qi Honglian; Gao Ge

1994-01-01

The authors introduce an analysing method that can determine simultaneously Ca, Fe, Cu and Zn in hair by using energy-dispersive X ray fluorescence analyzer of tube-excite type made in China. The added element Y is used as internal standard in hair sample. The hair is resolved by chemical reagent to make test sample, then the energy-dispersive X ray fluorescence analyzer is used to determine Ca, fe, Cu and Zn contents in hair sample. The lower limits of detection are 7 x 10 -6 , 1 x 10 -6 , 4 x 10 -6 , 3 x 10 -6 , respectively. Correlative coefficients of variations are 6%, 1%, 2%, 2%

Mechanisms controlling Cu, Fe, Mn, and Co profiles in peat of the Filson Creek Fen, northeastern Minnesota

Science.gov (United States)

Walton-Day, K.; Filipek, L.H.; Papp, C.S.E.

1990-01-01

Filson Creek Fen, located in northeastern Minnesota, overlies a Cu-Ni sulfide deposit. A site in the fen was studied to evaluate the hydrogeochemical mechanisms governing the development of Fe, Mn, Co, and Cu profiles in the peat. At the study site, surface peat approximately 1 m thick is separated from the underlying mineralized bedrock by a 6-12 m thickness of lake and glaciofluvial sediments and till. Concentrations of Fe, Mn, Co, and Cu in peat and major elements in pore water delineate a shallow, relatively oxidized, Cu-rich zone overlying a deeper, reduced, Fe-, Mn-, and Co-rich zone within the peat. Sequential metal extractions from peat samples reveal that 40-55% of the Cu in the shallow zone is associated with organic material, whereas the remaining Cu is distributed between iron-oxide, sulfide, and residual fractions. Sixty to seventy percent of the Fe, Mn, and Co concentrated in the deeper zone occur in the residual phase. The metal profiles and associations probably result from non-steady-state input of metals and detritus into the fen during formation of the peat column. The enrichment of organic-associated Cu in the upper, oxidized zone represents a combination of Cu transported into the fen with detrital plant fragments and soluble Cu, derived from weathering of outcrop and subcrop of the mineral deposit, transported into the fen, and fixed onto organic matter in the peat. The variable stratigraphy of the peat indicates that weathering processes and surface vegetation have changed through time in the fen. The Fe, Mn, and Co maxima at the base of the peat are associated with a maximum in detrital matter content of the peat resulting from a transition between the underlying inorganic sedimentary environment to an organic sedimentary environment. The chemistry of sediments and ground water collected beneath the peat indicate that mobilization of metals from sulfide minerals in the buried mineral deposit or glacial deposits is minimal. Therefore, the

The Effect of Nitrate Levels and Harvest Times on Fe, Zn, Cu, and K, Concentrations and Nitrate Reductase Activity in Lettuce and Spinach

Directory of Open Access Journals (Sweden)

Z. Gheshlaghi

2015-09-01

Full Text Available Leafy vegetables are considered as the main sources of nitrate in the human diet. In order to investigate the effect of nitrate levels and harvest times on nitrate accumulation, nitrate reductase activity, concentrations of Fe, Zn, Cu and K in Lettuce and Spinach and their relation to nitrate accumulation in these leafy vegetables, two harvest times (29 and 46 days after transplanting, two vegetable species of lettuce and spinach and two concentrations of nitrate (10 and 20 mM were used in a hydroponics greenhouse experiment with a completely randomized design and 3 replications. Modified Hoagland and Arnon nutrient solutions were used for the experiment. The results indicated that by increasing nitrate concentration of solution, nitrate accumulation in roots and shoots of lettuce and spinach increased significantly (P ≤ 0.05, and the same trend was observed for the nitrate reductase activity in the shoots of the two species. Increasing the nitrate concentrations of solution, reduced the shoot dry weight and the concentration of Fe and Cu in both species, where as it increased the K and Zn concentrations in the shoots of the two species in each both harvest times, the nitrate accumulation increased, but the nitrate reductase activity decreased in the shoots of the two species over the course of the growth. The Concentration of Fe, Cu and K decreased in the shoots of lettuce and the spinach with the time, despite the increase in Zn concentration in the shoots. The results also indicated that increasing nitrate concentrations of solution to the levels greater than the plant capacity for reduction and net uptake of nitrate, leads to the nitrate accumulation in the plants. Nitrate accumulation in plant tissue led to decreases in fresh shoot yield and Fe and Cu concentrations and nitrate reductase activities in both lettuce and spinach.

Role of heat on the development of electrochemical sensors on bare and modified Co{sub 3}O{sub 4}/CuO composite nanopowder carbon paste electrodes

Energy Technology Data Exchange (ETDEWEB)

Kumar, Mohan; Kumara Swamy, B.E., E-mail: kumaraswamy21@yahoo.com

2016-01-01

The Co{sub 3}O{sub 4}/CuO composite nanopowder (NP) was synthesized by a mechanochemical method and characterized by using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The synthesized Co{sub 3}O{sub 4}/CuO NP was used as a modified carbon paste electrode (MCPE) and further the bare carbon paste and Co{sub 3}O{sub 4}/CuO NP modified carbon paste was heated at different temperatures (100, 150, 200 and 250 °C) for 10 min. The Co{sub 3}O{sub 4}/CuO NP MCPE was used to study the consequences of scan rate and dopamine concentration. Furthermore the preheated modified electrodes were used to study the electrochemical response to dopamine (DA), ascorbic acid (AA) and uric acid (UA). - Highlights: • Co{sub 3}O{sub 4}/CuO composite nanopowders (NPs) are prepared by the mechanochemical method. • Co{sub 3}O{sub 4}/CuO was used as a modified electrode for detection of DA, AA and UA. • The role of temperature on the sensor development was studied. • The modified carbon paste electrode shows good sensitivity to DA and UA.

Novel La(Fe,Si){sub 13}/Cu composites for magnetic cooling

Energy Technology Data Exchange (ETDEWEB)

Lyubina, Julia; Hannemann, Ullrich; Ryan, Mary P. [Department of Materials, Imperial College London, London, SW7 2AZ (United Kingdom); Cohen, Lesley F. [Department of Physics, Imperial College London, London, SW7 2AZ (United Kingdom)

2012-11-15

An approach to engineering magnetic refrigerant materials with defined thermal transport properties is demonstrated using the example of high magnetocaloric performance La-Fe-Si alloys. A tunability of up to 300% of the thermal conductivity can be achieved in composites consisting of a La(Fe,Si){sub 13} compound and Cu prepared by electroless copper plating without compromising the magnitude of the magnetocaloric effect. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Study on the process of sintering matrix metallic Fe-Cu-25%Nb and Fe-Cu-25%Co during hot pressing

International Nuclear Information System (INIS)

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

2016-01-01

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

Characterisation of the antiferromagnetic transition of Cu2FeSnS4, the synthetic analogue of stannite

Science.gov (United States)

Caneschi, A.; Cipriani, C.; di Benedetto, F.; Sessoli, R.

2003-04-01

Magnetisation measurements between 260 and 1.9K were performed on the synthetic analogue of stannite, Cu_2FeSnS_4, tetragonal Ioverline{4}2m. Fe(II) ions, in the high spin S=2 configuration for tetrahedral coordination, are responsible for the high temperature paramagnetism. In agreement with Bernardini et al. (2000), an antiferromagnetic transition was observed, lowering temperature below 8K. Refined measurements evidenced a T_N=6.1K for the Néel temperature. In spite of a small difference, observed in the behaviour between the zero-field cooled and the field cooled curves, which suggests the possible presence of a spin-glass phase, the AC measurements did not provide evidence of dependence of the magnetic susceptibility on frequency, as expected in spin-glass systems. On the basis of the experimental data, in agreement with the existent literature (Fries et al., 1997), a collinear antiferromagnetic structure should be preferred. The Fe ions, in fact, are distributed in two sublattices obtained by magnetic differentiation of the symmetry equivalent (0,0,0) and (frac{1}{2}frac{1}{2}frac{1}{2}) Fe positions (wyckoff: 2a). The low value for the Nèel temperature, as compared e.g. to the room-temperature antiferromagnet chalcopyrite (CuFeS_2), very close in composition and structure to stannite, is to be related to the increased distance between the Fe ions (˜6.6Å). This weak interaction is not detected in natural samples, where diamagnetic Zn(II) replace paramagnetic Fe(II), thus increasing the mean Fe-Fe distance. Fries, T., Shapira, Y., Palacio, F., Moròn, M.C., McIntyre, G.J., Kershaw, R., Wold, A. and McNiff, E.J. Jr. (1997): Mangetic ordering of the antiferromagnet Cu_2MnSnS_4 from magnetisation and neutron-scattering measurements. Phys. Rev. B, 6(9), 5424-5431 Bernardini, G.P., Borrini, D., Caneschi, A. Di Benedetto, F., Gatteschi, D., Ristori, S. and Romanelli, M. (2000): EPR and SQUID magnetometry study of Cu_2FeSnS_4 (stannite) and Cu_2ZnSnS_4 (kesterite

Influence of Solution and Aging Treatment Conditions on the Formation of Ultrafine-Grained Structure of CuFe2 Alloy Processed by Rolling with Cyclic Movement of Rolls

Directory of Open Access Journals (Sweden)

Urbańczyk-Gucwa A.

2016-06-01

Full Text Available The effect of second phase particles on grain refinement in CuFe2 alloy has been investigated by using rolling with the cyclic movement of rolls (RCMR method. Two different population of second phase particles of Fe: coherent, about 10 nm in diameter and about 100 nm in size were obtained by applying aging treatment followed at 500°C for 2 h and at 700°C for 24 h respectively. In addition, solution treated samples were deformed by RCMR method at the same parameters. The microstructures of the CuFe2 alloy were analyzed using light microscope (LM, electron backscattered diffraction (EBSD microscope technique and scanning transmission electron microscope (STEM. The presence of high-density of coherent Fe particles in the matrix inhibits recovery process and in the result obtained grain/subgrain boundaries have diffused character and are weakly visible. The largest particles which are not coherent with the matrix act as an effective barrier against the boundary motion.

Study of the C-14-contamination potential of C-impurities in CuO and Fe

NARCIS (Netherlands)

Vandeputte, K; Moens, L; Dams, R; van der Plicht, Johannes

1998-01-01

The carbon concentration in CuO and iron was determined by isolating C. The values were in agreement with results reported in other studies. Contaminating carbon from CuO and Fe was transformed to AMS targets and measured for C-14. C-traces in CuO were shown to be the major contribution to the C-14

Effect of Mn and AlTiB Addition and Heattreatment on the Microstructures and Mechanical Properties of Al-Si-Fe-Cu-Zr Alloy.

Science.gov (United States)

Yoo, Hyo-Sang; Kim, Yong-Ho; Lee, Seong-Hee; Son, Hyeon-Taek

2018-09-01

The microstructure and mechanical properties of as-extruded Al-0.1 wt%Si-0.2 wt%Fe- 0.4 wt%Cu-0.04 wt%Zr-xMn-xAlTiB (x = 1.0 wt%) alloys under various annealing processes were investigated and compared. After the as-cast billets were kept at 400 °C for 1 hr, hot extrusion was carried out with a reduction ratio of 38:1. In the case of the as-extruded Al-Si-Fe-Cu-Zr alloy at annealed at 620 °C, large equiaxed grain was observed. When the Mn content is 1.0 wt%, the phase exhibits a skeleton morphology, the phase formation in which Mn participated. Also, the volume fraction of the intermetallic compounds increased with Mn and AlTiB addition. For the Al-0.1Si-0.2Fe-0.4Cu-0.04Zr alloy with Mn and AlTiB addition from 1.0 wt%, the ultimate tensile strength increased from 100.47 to 119.41 to 110.49 MPa. The tensile strength of the as-extruded alloys improved with the addition of Mn and AlTiB due to the formation of Mn and AlTiB-containing intermetallic compounds.

Probing structure-property relationships in perpendicularly magnetized Fe/Cu(001) using MXLD and XPD

Energy Technology Data Exchange (ETDEWEB)

Cummins, T.R.; Waddill, G.D. [Univ. of Missouri, Rolla, MO (United States); Goodman, K.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

Magnetic X-ray Linear Dichroism (MXLD) in Photoelectron Spectroscopy and X-Ray Photoelectron Diffraction (XPD) of the Fe 3p core level have been used to probe the magnetic structure-property relationships of perpendicularly magnetized Fe/Cu(001), in an element-specific fashion. A strong MEXLD effect was observed in the high resolution photoelectron spectroscopy of the Fe 3p at {open_quotes}normal{close_quotes} emission and was used to follow the loss of perpendicular ferromagnetic ordering as the temperature was raised toward room temperature. In parallel with this, {open_quotes}Forward Focussing{close_quotes} in XPD was used as a direct measure of geometric structure in the overlayer. These results and the implications of their correlation will be discussed. Additionally, an investigation of the effect of Mn doping of the Fe/Cu(001) will be described. These measurements were performed at the Spectromicroscopy Facility (Beamline 7.0.1) of the Advanced Light Source.

Fe3O4@HKUST-1 and Pd/Fe3O4@ HKUST-1 as magnetically recyclable catalysts prepared via conversion from a Cu-based ceramic

OpenAIRE

Toyao, Takashi; Styles, Mark J.; Yago, Tokuichiro; Sadiq, Muhammad M.; Ricco, Raffaele; Suzuki, Kiyonori; Horiuchi, Yu; Takahashi, Masahide; Matsuoka, Masaya; Falcaro, Paolo

2017-01-01

Nanocomposites obtained by integrating iron oxide magnetic nanoparticles (Fe3O4) into a metal-organic framework (HKUST-1 or Cu-3(BTC)(2), BTC = 1,3,5-benzenetricarboxylate) are synthesized through conversion from a composite of a Cu-based ceramic material and Fe3O4. In situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements reveal that the presence of Fe3O4 leads to the fast conversion and synthesis of HKUST-1 with small particle sizes. The prepared MOF co...

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

African Journals Online (AJOL)

SERVER

2008-03-18

Mar 18, 2008 ... Chemical analysis of the trace elements in the soft tissues. The trace elements of interest (Cu, Zn, Fe, Pb, Cd) were then determined in the digested solutions, using Thermoelemental type. M6 brand of an atomic absorption Spectrometer equipped with a flame operated atomisation system and a deuterium ...

High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C/Fe Trilayer Thin Films

Directory of Open Access Journals (Sweden)

Anabil Gayen

2013-01-01

Full Text Available We report the investigation of temperature dependent magnetic properties of FePt and FePt(30/M(Cu,C/Fe(5 trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures. L10 ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

Formation of the 1:2:3 structure in Y-Ba-Cu(Fe)-O system studied by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Valko, P.; Miglierini, M.; Sitek, J.; Hucl, M.; Gruskova, A.

1990-01-01

Annealing time and temperature dependence of Y, Ba, Cu, Fe nitrade mixture towards new phases creation was revealed by Moessbauer spectroscopy. The observed changes can be assigned to chemical decomposition of corresponding nitrades and creation of intermedial and final Y 1 Ba 2 (Cu 0.95 Fe 0.05 ) 3 O x phase. (orig.)

Effect of Ti content on structure and properties of Al2CrFeNiCoCuTix high-entropy alloy coatings

International Nuclear Information System (INIS)

Qiu, X.W.; Zhang, Y.P.; Liu, C.G.

2014-01-01

Highlights: • Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. • Al 2 CrFeNiCoCuTi x coatings show excellent corrosion resistance and wear resistance. • Al 2 CrFeNiCoCuTi x coatings play a good protective effect on Q235 steel. • Ti element promotes the formation of a BCC structure in a certain extent. -- Abstract: The Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. The structure, hardness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al 2 CrFeNiCoCuTi x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combination; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings is reduced by 1–2 orders of magnitude, the free-corrosion potential is more “positive”. With the increasing of Ti content, the corrosion resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings enhanced in 0.5 mol/L HNO 3 solution. Compared with Q235 steel, the relative wear resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti 0.0 high-entropy alloy is a kind of soft magnetic materials

Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

Energy Technology Data Exchange (ETDEWEB)

Antonov, A.S.; Buznikov, N.A. E-mail: n_buznikov@mail.ru; Granovsky, A.B.; Iakubov, I.T.; Prokoshin, A.F.; Rakhmanov, A.L.; Yakunin, A.M

2002-08-01

The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors.

Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

International Nuclear Information System (INIS)

Antonov, A.S.; Buznikov, N.A.; Granovsky, A.B.; Iakubov, I.T.; Prokoshin, A.F.; Rakhmanov, A.L.; Yakunin, A.M.

2002-01-01

The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors

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

International Nuclear Information System (INIS)

Xu, Yin; Ai, Jia; Zhang, Hui

2016-01-01

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

Efficient solar light-driven degradation of Congo red with novel Cu-loaded Fe3O4@TiO2 nanoparticles.

Science.gov (United States)

Arora, Priya; Fermah, Alisha; Rajput, Jaspreet Kaur; Singh, Harminder; Badhan, Jigyasa

2017-08-01

In this work, Cu-loaded Fe 3 O 4 @TiO 2 core shell nanoparticles were prepared in a single pot by coating of TiO 2 on Fe 3 O 4 nanoparticles followed by Cu loading. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), Brunauer-Emmett- Teller (BET), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and valence band X-ray photoelectron spectroscopy (VB XPS) techniques were used for characterization of as prepared nanoparticles. Synergism between copper and titania was evaluated by studying the solar light-driven photodegradation of Congo red dye solution in the presence of Fe 3 O 4 @TiO 2 nanoparticles on one side and Cu-loaded Fe 3 O 4 @TiO 2 nanoparticles on the other side. The latter performed better than the former catalyst, indicating the enhanced activity of copper-loaded catalyst. Further photodegradation was studied by three means, i.e., under ultraviolet (UV), refluxing, and solar radiations. Cu-loaded Fe 3 O 4 @TiO 2 enhanced the degradation efficiency of Congo red dye. Thus, Cu act possibly by reducing the band gap of TiO 2 and widening the optical response of semiconductor, as a result of which solar light could be used to carry out photocatalysis. Graphical abstract Photodegradation of congo red over Cu-loaded Fe 3 O 4 @TiO 2 nanoparticles.

An assessment of the homogeneity of nano-crystalline Fe-Cu powders as studied by means of APT

Energy Technology Data Exchange (ETDEWEB)

Wille, Catharina, E-mail: cwille@ump.gwdg.de [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany); Al-Kassab, Talaat [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany); Choi, Pyuck-Pa [Korea Institute of Science and Technology, Nano-Materials Research Center, Seoul (Korea, Republic of); Kwon, Young-Soon [Research Center for Machine Parts and Materials Processing, University of Ulsan, Ulsan (Korea, Republic of); Kirchheim, Reiner [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany)

2009-04-15

In this contribution the homogeneity of mechanically alloyed Fe-Cu powders for two different compositions (Fe-10 and Fe-2.5 at%Cu) has been systematically characterised by atom probe tomography. Since Fe-Cu exhibits the Invar effect, it is among the most attractive systems for technical application. Furthermore, this system is immiscible and characterised by a large positive heat of mixing. In combination with the widespread application and accessibility, this predestines Fe-Cu as a binary model alloy to elaborate the enforced nonequilibrium enhanced solubility for immiscible systems. Depending on the parameters composition and milling time, results on the extension of the solubility limit and on the homogeneity of the alloy are presented, discussed and compared to earlier works. Only for the alloy with lower Cu content and for the prolonged milling time of 50 h, chemical homogeneity of the sample as measured by the atom probe was fully reached on the nano-scale. For all other parameter combinations homogeneity could not be achieved, even for long milling times and for those samples that appear to be homogeneous via X-ray analysis. Moreover, impurities were determined, mostly stemming from the fabrication procedure. The arrangement and homogeneity of the most common impurity, oxygen, was evaluated from atom probe data for different samples. Thus, the local concentration, segregation effects and the distribution of impurities could be quantified on the nano-scale, depending on the different nominal compositions and processing parameters. Additionally, structural information could be gained employing transmission electron microscopy and diffraction measurements.

An assessment of the homogeneity of nano-crystalline Fe-Cu powders as studied by means of APT

International Nuclear Information System (INIS)

Wille, Catharina; Al-Kassab, Talaat; Choi, Pyuck-Pa; Kwon, Young-Soon; Kirchheim, Reiner

2009-01-01

In this contribution the homogeneity of mechanically alloyed Fe-Cu powders for two different compositions (Fe-10 and Fe-2.5 at%Cu) has been systematically characterised by atom probe tomography. Since Fe-Cu exhibits the Invar effect, it is among the most attractive systems for technical application. Furthermore, this system is immiscible and characterised by a large positive heat of mixing. In combination with the widespread application and accessibility, this predestines Fe-Cu as a binary model alloy to elaborate the enforced nonequilibrium enhanced solubility for immiscible systems. Depending on the parameters composition and milling time, results on the extension of the solubility limit and on the homogeneity of the alloy are presented, discussed and compared to earlier works. Only for the alloy with lower Cu content and for the prolonged milling time of 50 h, chemical homogeneity of the sample as measured by the atom probe was fully reached on the nano-scale. For all other parameter combinations homogeneity could not be achieved, even for long milling times and for those samples that appear to be homogeneous via X-ray analysis. Moreover, impurities were determined, mostly stemming from the fabrication procedure. The arrangement and homogeneity of the most common impurity, oxygen, was evaluated from atom probe data for different samples. Thus, the local concentration, segregation effects and the distribution of impurities could be quantified on the nano-scale, depending on the different nominal compositions and processing parameters. Additionally, structural information could be gained employing transmission electron microscopy and diffraction measurements.

Multifunctional polyoxometalates encapsulated in MIL-100(Fe): highly efficient photocatalysts for selective transformation under visible light.

Science.gov (United States)

Liang, Ruowen; Chen, Rui; Jing, Fenfen; Qin, Na; Wu, Ling

2015-11-07

H3PMo12O40 molecules have been successfully encapsulated in the cavities of MIL-100(Fe) via a facile hydrothermal method (denoted as HPMo@MIL-100(Fe)). A series of characterization has corroborated the insertion of H3PMo12O40 within the cavities of MIL-100(Fe). The resulting HPMo@MIL-100(Fe) nanocomposites have exhibited much higher photoactivity than the original-MIL-100(Fe) toward the photocatalytic selective oxidation of benzylic alcohols and the reduction of Cr(vi) under visible light irradiation (λ≥ 420 nm). The higher photoactivity of HPMo@MIL-100(Fe) can be attributed to the integrative effect of enhanced light absorption intensity and more efficient separation of photogenerated electron-hole pairs. The host porous structure of MIL-100(Fe) can achieve a uniform composition with H3PMo12O40, which is significantly important for producing highly reactive dispersed H3PMo12O40 molecules and enhancing the photocatalytic activity of HPMo@MIL-100(Fe) nanocomposites. And the immobilized H3PMo12O40 molecules are more convenient for recycling. Importantly, almost no Fe and Mo ions leach from the MIL-100(Fe) during the reaction, which verifies the photostability of the HPMo@MIL-100(Fe). In addition, possible photocatalytic redox reaction mechanisms have been investigated.

Nuclear Magnetic Resonance (NMR) study of the nanocrystalline alloy Fe73.5 Cu1 Nb3 Si13.5 B9

International Nuclear Information System (INIS)

Aliaga-Guerra, D.; Iannarella, L.; Fontes, M.B.; Guimaraes, A.P.; Skorvanek, I.

1994-05-01

Nanocrystalline Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 alloys were studied with spin echo NMR at 4.2 K, from 15 to 100 MHz. Several lines are observed, with signals from domains and domain walls. Signals at 50-90 MHz appear to arise from 93 Nb nuclei in the amorphous matrix and in the interface of the crystallites. (author). 5 refs, 3 figs

The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

Directory of Open Access Journals (Sweden)

Dilermando Nagle Travessa

2012-10-01

Full Text Available In order to obtain quasicrystalline (QC phase by mechanical alloying (MA in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. % were produced by high energy ball milling (HEBM. A very high energy type mill (spex and short milling times (up to 5 hours were employed. The resulting powders were characterized by X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopy (SEM. QC phase was not directly formed by milling under the conditions employed in this work. However, phase transformations identified by DSC analysis reveals that annealing after HEBM possibly results in the formation of the ψ QC phase.

The evaluation of Young's modulus and residual stress of Cu films by NiFe/Cu bilayer film microbridge tests

International Nuclear Information System (INIS)

Zhou Zhimin; Zhou Yong; Cao Ying; Ding Wen; Mao Haiping

2008-01-01

This paper proposes a method to estimate the thickness limit for single-layer microbridge tests and also the thickness limit of one film on another film with known thickness for bilayer microbridge tests. To evaluate the mechanical properties of the Cu film, which could not be measured by single-layer microbridge tests, the NiFe single-layer film and NiFe/Cu bilayer film on silicon substrate are fabricated onto the microbridge by the MEMS technique. A load–deflection experiment is conducted upon the ceramic shaft adhered to the microbridge center by means of the XP nanoindenter system. From single-layer microbridge theory, Young's modulus and the residual stress of the NiFe film are deduced to be 192.74 ± 8.10 GPa and 287.75 ± 16.18 MPa, respectively. The data are introduced into bilayer microbridge theory and Young's modulus and the residual stress of the copper film are calculated to be 118.71 ± 6.54 GPa and 41.34 ± 4.42 MPa, respectively. The experimental results correspond well with those of nanoindentation

Preparation of Cu-Fe-Al-O nanosheets and their catalytic application in methanol steam reforming for hydrogen production

Science.gov (United States)

Wang, Leilei; Zhang, Fan; Miao, Dinghao; Zhang, Lei; Ren, Tiezhen; Hui, Xidong; He, Zhanbing

2017-03-01

Candidates of precious metal catalysts, prepared in a facile and environmental way and showing high catalytic performances at low temperatures, are always highly desired by industry. In this work, large-scale Cu-Fe-Al-O nanosheets were synthesized by facile dealloying of Al-Cu-Fe alloys in NaOH solution. The composition, microscopic morphology, and crystal structure were respectively investigated using wavelength-dispersive x-ray spectroscopy with an electron probe microanalyzer, scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. Furthermore, we found that the 2D Cu-Fe-Al-O nanosheets gave excellent catalytic performances in hydrogen production by methanol steam reforming at relatively low temperatures, e.g. 513 K.

Vibrational properties of stannite and kesterite type compounds: Raman scattering analysis of Cu2(Fe,Zn)SnS4

International Nuclear Information System (INIS)

Fontané, X.; Izquierdo-Roca, V.; Saucedo, E.; Schorr, S.; Yukhymchuk, V.O.; Valakh, M.Ya.; Pérez-Rodríguez, A.; Morante, J.R.

2012-01-01

Highlights: ► Analysis of main and weaker Raman peaks from Cu 2 FeZnS 4 and Cu 2 ZnSnS 4 compounds. ► Identification of a cation disorder induced Raman peak in Cu 2 ZnSnS 4 . ► Analysis of spectral features of main Raman peaks from Cu 2 (Fe,Zn)SnS 4 . - Abstract: This work reports the analysis of the vibrational properties of stannite–kesterite Cu 2 (Fe,Zn)SnS 4 compounds that has been performed by Raman scattering measurements. The detailed analysis of the experimental spectra has allowed determining the frequency and symmetry assignment of the main and weaker peaks from both stannite Cu 2 FeSnS 4 (CFTS) and kesterite Cu 2 ZnSnS 4 (CZTS) phases. The measurements performed in the kesterite CZTS samples have also revealed the presence of local inhomogeneities that are characterised by an additional peak in the spectra at about 331 cm −1 . This peak has been related to the presence in these local regions of a high degree of disorder in the cation sublattice, in agreement with previous neutron diffraction analysis in similar samples. Finally, the spectra from the solid solution alloys show a one-mode behaviour of the main A/A 1 peak with the chemical composition.

The Influence of CuFe2O4 Nanoparticles on Superconductivity of MgB2

Science.gov (United States)

Novosel, Nikolina; Pajić, Damir; Skoko, Željko; Mustapić, Mislav; Babić, Emil; Zadro, Krešo; Horvat, Joseph

The influence of CuFe2O4 nanoparticle doping on superconducting properties of Fe-sheated MgB2 wires has been studied. The wires containing 0, 3 and 7.5 wt.% of monodisperse superparamagnetic nanoparticles (˜7 nm) were sintered at 650°C or 750°C for 1 hour in the pure argon atmosphere. X-ray diffraction patterns of doped samples showed very small maxima corresponding to iron boride and an increase in the fraction of MgO phase indicating some interaction of nanoparticles with Mg and B. Both magnetic and transport measurements (performed in the temperature range 2-42 K and magnetic field up to 16 T) showed strong deterioration of the superconducting properties upon doping with CuFe2O4. The transition temperatures, Tc, of doped samples decreased for about 1.4 K per wt.% of CuFe2O4. Also, the irreversibility fields Birr(T) decreased progressively with increasing doping. Accordingly, also the suppression of Jc with magnetic field became stronger. The observed strong deterioration of superconducting properties of MgB2 wires is at variance with reported enhancement of critical currents at higher temperatures (determined from magnetization) in bulk MgB2 samples doped with Fe3O4 nanoparticles. The probable reason for this discrepancy is briefly discussed

Orbital topology, interlayer spin coupling, and magnetic anisotropy of the CuFeO2 compound

NARCIS (Netherlands)

Malvestuto, M.; Bondino, F.; Magnano, E.; Lummen, T. T. A.; van Loosdrecht, P. H. M.; Parmigiani, F.

2011-01-01

X-ray absorption spectroscopy performed on a CuFeO2 single crystal reveals the pivotal role of the Cu ions in the discussion of the anisotropic properties of the compound. In particular, it is shown that there is a 3d hole density on the nominal 3d(10) Cu+ ions which may lie at the origin of the

Separations on a cellulose exchanger with salicylic acid as functional group. [Fe/sup 3//sup+//Cu/sup 2//sup+/, Cu/sup 2//sup+//Ni/sup 2//sup+//, and Cu/sup 2//sup+//Cu complex separations

Energy Technology Data Exchange (ETDEWEB)

Burba, P; Lieser, K H [Technische Hochschule Darmstadt (F.R. Germany). Fachbereich Anorganische Chemie und Kernchemie

1976-07-01

The use of a cellulose compound containing salicylic acid as functional group (capacity 0.6 mequ./g) for different problems is described. The seperations Fe/sup 3 +//Cu/sup 2 +/ and Cu/sup 2 +//Ni/sup 2 +/ in aqueous solutions are achieved smoothly at pH 2 and 2.5 resp. In organic solvents (pyridine) copper ions are separated from copper complexes as shown by the examples Cu/sup 2 +//(Cu(mnt)/sub 2/)/sup 2 -/ (mnt = maleonitril-1,2-dithiolate) and Cu/sup 2 +//dibenzo(b.i.)(5.9.14.18)tetraazacyclotetradecene-copper (Cu(chel)). The complex (Cu(mnt)/sub 2/)/sup 2 -/ can be labelled with Cu-64 on a separation column, whereas (Cu-(chel)) is substition inert.

One-step synthesis Fe{sub 3}N surface-modified Fe{sub 3}O{sub 4} nanoparticles with excellent lithium storage ability

Energy Technology Data Exchange (ETDEWEB)

Li, Yabin [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Institute of Chemical Power Sources, Soochow University, Suzhou 215006 (China); Yan, Yuerong [Department of Science and Technology, Jiaozuo Teachers College, Jiaozuo 454000 (China); Ming, Hai, E-mail: lunaticmh@163.com [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Institute of Chemical Power Sources, Soochow University, Suzhou 215006 (China); Zheng, Junwei, E-mail: jwzheng@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Institute of Chemical Power Sources, Soochow University, Suzhou 215006 (China)

2014-06-01

The Fe{sub 3}N modified Fe{sub 3}O{sub 4} nanoparticles with an excellent performance in lithium-ion batteries were prepared via a one-step and an efficient method. The layer of Fe{sub 3}N could significantly decrease the variation of volume and enhance the conductivity of Fe{sub 3}O{sub 4} simultaneously during the reaction of lithium ions in the charge-discharge process. There are two main advantages of this material: (1) their size distribution, ranging from 100 to 500 nm and (2) the fact that these particles are connected with each other by the Fe{sub 3}N layer. These two features allow such material to exhibit a high reversible capacity of 739 and 620 mA h g{sup −1} after each 60 cycles at the current density of 50 and 200 mA g{sup −1}, respectively. More importantly, since its introduction, this new concept of coating metal oxides with a layer of metal nitride to form core-shell structured metal oxide@metal nitride can be widely applied in the fields of catalysis, electrochemistry, energy, environmental and materials science with improved performance.

Evaluation of Antioxidant and Cytotoxicity Activities of Copper Ferrite (CuFe2O4 and Zinc Ferrite (ZnFe2O4 Nanoparticles Synthesized by Sol-Gel Self-Combustion Method

Directory of Open Access Journals (Sweden)

Samikannu Kanagesan

2016-08-01

Full Text Available Spinel copper ferrite (CuFe2O4 and zinc ferrite (ZnFe2O4 nanoparticles were synthesized using a sol-gel self-combustion technique. The structural, functional, morphological and magnetic properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, Transmission electron microscopy (TEM and vibrating sample magnetometry (VSM. XRD patterns conform to the copper ferrite and zinc ferrite formation, and the average particle sizes were calculated by using a transmission electron microscope, the measured particle sizes being 56 nm for CuFe2O4 and 68 nm for ZnFe2O4. Both spinel ferrite nanoparticles exhibit ferromagnetic behavior with saturation magnetization of 31 emug−1 for copper ferrite (50.63 Am2/Kg and 28.8 Am2/Kg for zinc ferrite. Both synthesized ferrite nanoparticles were equally effective in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH free radicals. ZnFe2O4 and CuFe2O4 nanoparticles showed 30.57% ± 1.0% and 28.69% ± 1.14% scavenging activity at 125 µg/mL concentrations. In vitro cytotoxicity study revealed higher concentrations (>125 µg/mL of ZnFe2O4 and CuFe2O4 with increased toxicity against MCF-7 cells, but were found to be non-toxic at lower concentrations suggesting their biocompatibility.

Coercive force changes in Sm(CoFeCuZr)z during step-like heat treatments

International Nuclear Information System (INIS)

Puzanova, T.Z.; Shchegoleva, N.N.; Sakhnova, L.V.; Majkov, V.G.; Shur, Ya.S.; Nikolaeva, N.V.

1987-01-01

Sm(Co 0.67 Fe 0.22 Cu 0.08 Zr 0.03 ) 8.35 alloy, contaning two homogeneous solid solutions SmM 6.85 and SmM 7.75 (M=Co, Fe, Cu, Zr) after high-temperature treatment, is investigated. It is shown, that after isothermal tempering at 800 deg C, SmM 6.85 and SmM 7.75 are close by microstructure and their coercive forces change in a different way during step-like cooling within 700-400 deg C interval. Possibility of producing material, single-phase in magnetic relation, is discussed

Moessbauer study of isothermally annealed amorphous Fe-Nb-Cu-Si-B alloys

International Nuclear Information System (INIS)

Sitek, J.; Toth, I.; Miglierini, M.

1993-01-01

Amorphous ribbons of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 have been annealed above the crystallization temperature. Annealed samples consisted of crystalline and amorphous phases in a wide temperature range. Two samples of different thicknesses of 33 μm and 27 μm were isothermally annealed at a temperature of 545 C from 0.5 to 5 h in a vacuum furnace. The amount of crystalline phase increases rapidly in the ticker sample. The crystalline part of the Moessbauer spectrum consists of four sharp sextets which can be assigned to a DO 3 -structure FeSi alloy. After 700 C annealing the amorphous phase was not observed and the crystalline phase consisted of the DO 3 -structure FeSi alloy, paramagnetic FeNbB and presumably Fe 23 B 6 and Fe 3 SiB 2 . (orig.)

Al-matrix composite materials reinforced by Al-Cu-Fe particles

International Nuclear Information System (INIS)

Bonneville, J; Laplanche, G; Joulain, A; Gauthier-Brunet, V; Dubois, S

2010-01-01

Al-matrix material composites were produced using hot isostatic pressing technique, starting with pure Al and icosahedral (i) Al-Cu-Fe powders. Depending on the processing temperature, the final reinforcement particles are either still of the initial i-phase or transformed into the tetragonal ω-Al0 0.70 Cu 0.20 Fe 0.10 crystalline phase. Compression tests performed in the temperature range 293K - 823K on the two types of composite, i.e. Al/i and Al/ω, indicate that the flow stress of both composites is strongly temperature dependent and exhibit distinct regimes with increasing temperature. Differences exist between the two composites, in particular in yield stress values. In the low temperature regime (T ≤ 570K), the yield stress of the Al/ω composite is nearly 75% higher than that of the Al/i composite, while for T > 570K both composites exhibit similar yield stress values. The results are interpreted in terms of load transfer contribution between the matrix and the reinforcement particles and elementary dislocation mechanisms in the Al matrix.

Teores de Fe, Mn, Zn, Cu, Ni E Co em solos de referência de Pernambuco

Directory of Open Access Journals (Sweden)

Caroline Miranda Biondi

2011-06-01

Full Text Available Metais pesados formam um grupo de elementos com particularidades relevantes e de ocorrência natural no ambiente, como elementos acessórios na constituição de rochas. Esses elementos, apesar de associados à toxidez, exigem tratamento diferenciado em relação aos xenobióticos, uma vez que diversos metais possuem essencialidade (Fe, Mn, Cu, Zn e Ni e benefício (Co comprovados para as plantas. Nesse contexto, o objetivo deste trabalho foi determinar os teores naturais dos metais Fe, Mn, Zn, Ni, Cu e Co nos solos de referência de Pernambuco. Foram coletadas amostras de solo nas três regiões fisiográficas (Zona da Mata, Agreste e Sertão, dos dois primeiros horizontes dos 35 solos de referência do Estado de Pernambuco. A digestão das amostras baseou-se no método 3051A (USEPA, 1998, e a determinação foi efetuada em ICP-OES. Correlações significativas foram estabelecidas entre os metais e entre estes e a fração argila do solo, em ambos os horizontes, indicando a associação comum da maioria dos metais com solos mais argilosos. A maioria dos solos apresentou teores de Fe, Mn, Zn, Cu, Ni e Co menores que os de solos de outras regiões do País, com litologia mais máfica, o que corrobora o fato de que os teores desses elementos são mais diretamente relacionados aos minerais Fe-magnesianos. Os resultados indicam baixo potencial dos solos de Pernambuco em liberar Cu, Co e Ni para plantas, enquanto deficiências de Zn, Fe e Mn são menos prováveis. Os teores naturais de Fe, Mn, Zn, Cu, Ni e Co determinados podem ser utilizados como base para definição dos Valores de Referência de Qualidade para os solos de Pernambuco, de acordo com o preconizado pela legislação nacional.

Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

Science.gov (United States)

Castin, N.; Malerba, L.; Bonny, G.; Pascuet, M. I.; Hou, M.

2009-09-01

We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

International Nuclear Information System (INIS)

Castin, N.; Malerba, L.; Bonny, G.; Pascuet, M.I.; Hou, M.

2009-01-01

We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

Energy Technology Data Exchange (ETDEWEB)

Castin, N. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); Physique des Solides Irradies et des Nanostructures (PSIN), Universite Libre de Bruxelles (ULB), Boulevard du Triomphe CP234, 1050 Brussels (Belgium); Malerba, L. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium)], E-mail: lmalerba@sckcen.be; Bonny, G. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); Laboratory of Theoretical Physics, Universiteit Gent, Proeftuinstraat 86, B-9000 Gent (Belgium); Pascuet, M.I. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); CAC-CNEA, Departamento de Materiales, Avda. Gral. Paz 1499, 1650 San Martin, Pcia. Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917, 1033 Buenos Aires (Argentina); Hou, M. [Physique des Solides Irradies et des Nanostructures (PSIN), Universite Libre de Bruxelles (ULB), Boulevard du Triomphe CP234, 1050 Brussels (Belgium)

2009-09-15

We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

Structure and magnetism of ultrathin Co and Fe films epitaxially grown on Pd/Cu(0 0 1)

International Nuclear Information System (INIS)

Lu, Y.F.; Przybylski, M.; Yan, L.; Barthel, J.; Meyerheim, H.L.; Kirschner, J.

2005-01-01

A contribution originating from the Co/Pd and Fe/Pd interfaces to the magneto-optical Kerr effect (MOKE) rotation is analyzed for Co and/or Fe films grown on a Pd-buffer-monolayer on Cu(0 0 1). A clear increase of the MOKE signal in comparison to the Co(Fe) films grown directly on Cu(0 0 1) is detected. An interpretation is supported by similar observations for Co films grown on Pd(1 1 0) and Pd(0 0 1). In particular, the sign reversal of the Kerr loops with increasing thickness of the Co(Fe) films is discussed. Magneto-optical effects are separated from the real magnetization and its dependence on the film thickness

Pyridoxal derived chemosensor for chromogenic sensing of Cu2+ and fluorogenic sensing of Fe3+ in semi-aqueous medium

International Nuclear Information System (INIS)

Sahoo, Suban K.; Sharma, Darshna; Moirangthem, Anuradha; Kuba, Aman; Thomas, Rini; Kumar, Rajender; Kuwar, Anil; Choi, Heung-Jin; Basu, Anupam

2016-01-01

An easy-to-prepare chemosensor L was developed by condensation of pyridoxal with 1,8-diaminonaphthalene. In DMSO:H 2 O (1:1, v/v), sensor L displayed a highly selective and sensitive response towards Cu 2+ via perceptible color and UV–vis absorbance changes among the other tested metal ions. However, the fluorescence of L is selectively quenched in the presence of both Fe 3+ and Cu 2+ . With a micromolar detection limit and non-interference from other co-existing metal ions, this sensor can be applied over a wide pH range for the detection of Fe 3+ and Cu 2+ . In addition, the cytotoxicity and fluorescence changes of L within live HeLa cells were examined in the absence and presence of Cu 2+ . - Highlights: • A new noncytotoxic chemosensor derived from vitamin B 6 cofactor was introduced. • Sensor showed colorimetric sensing ability towards Cu 2+ . • Sensor showed fluorescent turn-off sensing ability towards Fe 3+ and Cu 2+ . • Detection limit was better than the prescribed permissible limit.

Mecano-synthesis of the alloy 25%Fe-50%Cu-25%Nb

International Nuclear Information System (INIS)

Sousa, Keytiane; Oliveira, Michel Picanco de; Guimaraes, Renan da Silva; Moreira Junior, Valdenir; Filgueira, Marcello

2016-01-01

In general, this study aims at the application of mechanical grinding to the system 25% Fe-50% Cu-25% Nb and studies the production process of these powders during milling. The evolution of the structure during the synthesis and the effect of variation of the grinding time were studied by diffraction of X-rays (XRD) and Scanning Electron Microscopy coupled EDS (SEM + EDS) in order to obtain the sizes of crystallites, the phase formation and its evolution with grinding time, and also the homogeneity of the mixture. The particle size distribution was analyzed by laser sedigraph technique. The powders synthesis were performed for milling time of 2.5, 5 and 10 hours. The mechanical grinding showed to be effective with the solid solution formation in the early grinding times. The XRD showed the solid solution formation with subsequent reduction and disappearance of Cu peaks. Through the technique of laser sedigraph it was observed the increase of the particle size followed by the its reduction in the milling time of 10h, a fact that characterizes the mechanical grinding process for ductile powder particles. Thus, the study demonstrated the effectiveness of the mechanical grinding to obtain powder of Fe-Cu-Nb and further processing and application of diamond cutting tools. (author)

Application of Triton X-100 coated poly vinyl chloride as new solid phase for preconcentration of Fe3+, Cu2+ and Zn2+ ions and their flame atomic absorption spectrometric determinations

Directory of Open Access Journals (Sweden)

Mehrorang Ghaedi

2010-04-01

Full Text Available A selective, sensitive and efficient method for preconcentration of trace amounts of Cu(II, Fe(II and Zn(II ions based on the uptake of their complexes with 3-((indolin-3-yl(phenylmethylindoline (IYPMI loaded on Triton X-100 coated poly vinyl chloride has been reported. The influences of the analytical parameters including pH, ligand amount, surfactant type and concentration, eluting condition and sample volume on metal ions recovery were investigated. The method has been successfully applied for the extraction of these ions content in some real samples of soil and plants. The extraction efficiency was > 97% with low relative standard deviation (RSD < 2.4% and the preconcentration factor of 90 (5 mL elution volume for a 450 mL of sample volume.

Nitrite to nitric oxide interconversion by heme FeII complex assisted by [CuI(tmpa)]+

KAUST Repository

Turias, Francesc; Solà , Miquel; Falivene, Laura; Cavallo, Luigi; Poater, Albert

2015-01-01

The present computational study complements the recent experimental efforts by Karlin and coworkers to describe the interconversion of nitrite to nitric oxide by means of an iron porphyrin complex together with a Cu chemical system, i.e., the iron(II) complex (F8TPP)FeII [F8TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2−)] and a preformed copper(II)–nitrito complex [(tmpa)CuII(NO2)][B(C6F5)4] [tmpa = tris(2-pyridylmethyl)amine], being the latter an oxidized species of [(tmpa)CuI(MeCN)]+. By DFT calculations, we unravel how the reduction of nitrite to nitric oxide takes place through a μ-oxo heme-FeIII–O–CuII complex, following a mimetic path as in the cytochrome c oxidase. Mayer bond order (MBO) and energy decomposition analyses are used to analyze the bonding strength of such nitro derivatives to either copper or iron. © 2015 Springer Science+Business Media New York

Nitrite to nitric oxide interconversion by heme FeII complex assisted by [CuI(tmpa)]+

KAUST Repository

Turias, Francesc

2015-09-09

The present computational study complements the recent experimental efforts by Karlin and coworkers to describe the interconversion of nitrite to nitric oxide by means of an iron porphyrin complex together with a Cu chemical system, i.e., the iron(II) complex (F8TPP)FeII [F8TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2−)] and a preformed copper(II)–nitrito complex [(tmpa)CuII(NO2)][B(C6F5)4] [tmpa = tris(2-pyridylmethyl)amine], being the latter an oxidized species of [(tmpa)CuI(MeCN)]+. By DFT calculations, we unravel how the reduction of nitrite to nitric oxide takes place through a μ-oxo heme-FeIII–O–CuII complex, following a mimetic path as in the cytochrome c oxidase. Mayer bond order (MBO) and energy decomposition analyses are used to analyze the bonding strength of such nitro derivatives to either copper or iron. © 2015 Springer Science+Business Media New York

Radio-frequency (RF) studies of the magneto-dielectric composites: Cr{sub 0.75}Fe{sub 1.25}O{sub 3} (CRFO)-Fe{sub 0.5}Cu{sub 0.75}Ti{sub 0.75}O{sub 3} (FCTO)

Energy Technology Data Exchange (ETDEWEB)

Rocha, H.H.B. [Departamento de Engenharia de Teleinformatica (DETI), Universidade Federal do Ceara, Caixa Postal 6007, CEP 60755-640, Fortaleza, CE (Brazil); Laboratorio de Telecomunicacoes e Ciencia e Engenharia dos Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, CEP 60455-760, Fortaleza, CE (Brazil); Freire, F.N.A. [Departamento de Quimica Organica e Inorganica, Universidade Federal do Ceara, CEP 60455-760, Fortaleza, CE (Brazil); Santos, M.R.P.; Sasaki, J.M. [Laboratorio de Telecomunicacoes e Ciencia e Engenharia dos Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, CEP 60455-760, Fortaleza, CE (Brazil); Cordaro, T. [Celestica do Brasil Ltda, Rod Sp 340 km 128.7-Cp 151, CEP 13820-000, Jaguariuna, SP (Brazil); Sombra, A.S.B. [Laboratorio de Telecomunicacoes e Ciencia e Engenharia dos Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, CEP 60455-760, Fortaleza, CE (Brazil)], E-mail: sombra@fisica.ufc.br

2008-08-01

This paper concerns a study about the electrical properties of Cr{sub 0.75}Fe{sub 1.25}O{sub 3} (CRFO)/Fe{sub 0.5}Cu{sub 0.75}Ti{sub 0.75}O{sub 3} (FCTO) magneto-dielectric composites. These compounds were prepared by the conventional solid-state reaction synthesis. The samples synthesized, as well their two-phase composites [Cr{sub 0.75}Fe{sub 1.25}O{sub 3}]{sub Z}-[Fe{sub 0.5}Cu{sub 0.75}Ti{sub 0.75}O{sub 3}]{sub 100-Z} (Z=17, 34, 50, 66, 83), were characterized by X-ray powder diffraction technique (XRD). Rietveld's method was employed to verify the quantitative phase abundances in the composites' and their theoretical densities, which were compared with the experimental densities (pycnometer method). To predict the effect of the phases in the composites effective dielectric function ({kappa}), traditional dielectric mixing models such as parallel, series, and Lichtenecker's model were observed. An alternative approach, a sigmoidal fitting function based on the Boltzmann equation, was proposed to fit the experimental data.

Synthesis, spectroscopic analysis and electrochemical performance of modified β-nickel hydroxide electrode with CuO

Directory of Open Access Journals (Sweden)

B. Shruthi

2017-03-01

Full Text Available In the present work, a modified β-nickel hydroxide (β-Ni(OH2 electrode material with CuO has been prepared using a co-precipitation method. The structure and property of the modified β-Ni(OH2 with CuO were characterized by X-ray diffraction (XRD, Fourier Transform infra-red (FT-IR, Raman and thermal gravimetric-differential thermal analysis (TG-DTA techniques. The results of the FT-IR spectroscopy and TG-DTA indicate that the modified β-Ni(OH2 electrode materials contain intercalated water molecules and anions. A pasted–type electrode was prepared using nickel hydroxide powder as the main active material on a nickel sheet as a current collector. Cyclic voltammetry (CV and Electrochemical impedance spectroscopy (EIS studies were undertaken to assess the electrochemical behavior of pure β-Ni(OH2 and modified β-Ni(OH2 electrode with CuO in a 6 M KOH electrolyte. The addition of CuO into β-nickel hydroxide was found to enhance the reversibility of the electrode reaction and also increase the separation of the oxidation current peak of the active material from the oxygen evolution current. The modified nickel hydroxide with CuO was also found to exhibit a higher proton diffusion coefficient and a lower charge transfer resistance. These findings suggest that the modified β-Ni(OH2 with CuO possesses an enhanced electrochemical response and thus can be recognized as a promising candidate for battery electrode applications.

Synthesis and characterization of pure and (Ce, Zr, Ag) doped mesoporous CuO-Fe{sub 2}O{sub 3} as highly efficient and stable nanocatalysts for CO oxidation at low temperature

Energy Technology Data Exchange (ETDEWEB)

Said, Abd El-Aziz A., E-mail: aasaid55@yahoo.com; Abd El-Wahab, Mohamed M.M.; Goda, Mohamed N.

2016-12-30

Highlights: • Highly active and stable Fe-Cu mixed oxides were prepared by co-precipitation method. • Addition of CuO to Fe{sub 2}O{sub 3} increases the chemisorbed oxygen, the conductivity and S{sub BET}. • Activation energy of CO oxidation significantly decreased via doping with foreign ions. - Abstract: A series of single and mixed oxide nanocatalysts of mesoporous CuO-Fe{sub 2}O{sub 3} with different CuO contents (1–50 wt.%) were prepared by a co-precipitation method and further promoted by trace amounts of CeO{sub 2}, ZrO{sub 2} and Ag{sub 2}O (0.1–0.5 wt.%) dopants. The original and calcined catalysts were characterized by TG, DTA, XRD, TEM, VSM, N{sub 2} sorption analysis, surface chemisorbed oxygen and DC electrical conductivity measurements. The catalytic performance of these nanocatalysts toward CO oxidation was studied using a conventional fixed bed flow type reactor. The results revealed that the addition of 1–20 wt.% CuO to Fe{sub 2}O{sub 3} monotonically increases the specific surface area, the amount of surface chemisorbed oxygen, electrical conductivity and catalytic activity of the nanocatalysts. In addition, the catalytic activity indicated that Fe-Cu mixed oxide nanocatalyst promoted with the three dopants (CeO{sub 2}, ZrO{sub 2} and Ag{sub 2}O) exhibited the highest catalytic activity with a total conversion of CO into CO{sub 2} at 100 °C. Moreover, the activation energy of CO oxidation decreased from 38.4 to 23.1 kJmol{sup −1} upon treating the catalyst containing 20 wt.% CuO with the three dopants. Finally the effects of various operational parameters were also studied.

ONE-DIMENSIONAL ORDERING OF IN ATOMS IN A CU(100) SURFACE

NARCIS (Netherlands)

BREEMAN, M; BARKEMA, GT; BOERMA, DO

1994-01-01

A Monte Carlo study of the ordering of In atoms embedded in the top layer of a Cu(100) surface is presented. The interaction energies between the In and Cu atoms were derived from atom-embedding calculations, with Finnis-Sinclair potentials. It was found that the interaction between In atoms in the

Influence of Oxygen Partial Pressure during Processing on the Thermoelectric Properties of Aerosol-Deposited CuFeO₂.

Science.gov (United States)

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

2016-03-24

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

Determination of Mn, Fe, and Cu in chemically-treated wood pulps by the XRF addition method

Energy Technology Data Exchange (ETDEWEB)

Raemoe, J.; Klasila, T.; Piepponen, S. [VTT Chemical Technology (Finland); Sillanpaeae, M. [Oulu Univ. (Finland)

2001-08-01

A rapid X-ray fluorescence addition method has been developed for quantification of the technically most important metals in wood pulp matrix (Mn, Fe, and Cu). Pretreatment consisted of just two steps: first, acid was added to the sample to achieve homogeneous distribution of the metals; the pulp was then pressed lightly on to Mylar film. Total analysis time was less than 10 min. The concentration range investigated was up to 15 mg kg{sup -1} for Mn and up to 5 mg kg{sup -1} for Fe and Cu. Metal concentrations in Scandinavian pulps are not expected to exceed these amounts. The quantification limit was 2 mg kg{sup -1} for all three metals. The reproducibilities and repeatabilities were concentration-dependent and varied between 3 and 19% and between 1 and 17%, respectively. The squares of the linear correlation coefficients between measured intensity and added metal concentration were 0.994, 0.950, and 0.932 for Mn, Fe, and Cu, respectively. (orig.)

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

Study of dipole interaction in micron-width NiFe/Cu/NiFe/NiO wire using exchange anisotropy

International Nuclear Information System (INIS)

Kimura, Takashi; Itagaki, Yoshio; Wakaya, Fujio; Gamo, Kenji

2001-01-01

The dipole interaction between a NiFe layer pinned by a NiO and a free NiFe layer in a micron-wide NiFe/Cu/NiFe/NiO wire was studied by changing the direction of the exchange bias from the NiO layer. The effect of the dipole interaction when the exchange bias was perpendicular to the wire axis was larger than that when the exchange bias was parallel to the wire axis, and was consistently explained by the stray field caused by the magnetic charges of the pinned layer. It was demonstrated that this method, using exchange anisotropy, is useful for investigating the dipole interaction between ferromagnetic materials separated by a nonmagnetic material in small-scale magnetic multilayers. [copyright] 2001 American Institute of Physics

Influence of alloying element of corrosion of Zr-Nb-Sn-Fe-Cu alloy and impedance characteristics of its oxide layer

International Nuclear Information System (INIS)

Park, S. Y.; Lee, M. H.; Choi, B. K.; Jung, Y. H.; Jung, Y. H.

2000-01-01

As a part of the advanced Zr fuel cladding development program, the autoclave corrosion test was performed on the series of Zr-0.2Nb-1.1Sn-Fe-Cu and Zr-0.4Nb-0.8Sn-Fe-Cu alloys in 70 ppm LiOH solution at 360 .deg. C. The oxide characteristics were investigated by using the Electrochemical Impedance Spectroscope(EIS) method. The corrosion resistance of the alloys was evaluated from the corrosion rate determined as a function of the concentration of main alloying elements such as Nb, Sn, Fe and Cu. The equivalent circuit was composed as a result of the spectrum from EIS measurements on the oxide layer that formed at pro- and post-transition regions. By using the capacitance characteristics of equivalent circuit, the thickness of impervious layer, it's electrical resistance and characteristics of space charge layer were evaluated. The corrosion characteristics of the Zr-Nb-Sn-Fe-Cu alloys were successfully explained by applying the EIS test results

Effective removal of heavy metal ions Cd2+, Zn2+, Pb2+, Cu2+ from aqueous solution by polymer-modified magnetic nanoparticles

International Nuclear Information System (INIS)

Ge, Fei; Li, Meng-Meng; Ye, Hui; Zhao, Bao-Xiang

2012-01-01

We prepared novel Fe 3 O 4 magnetic nanoparticles (MNPs) modified with 3-aminopropyltriethoxysilane (APS) and copolymers of acrylic acid (AA) and crotonic acid (CA). The MNPs were characterized by transmission electron microscopy, X-ray diffraction, infra-red spectra and thermogravimetric analysis. We explored the ability of the MNPs for removing heavy metal ions (Cd 2+ , Zn 2+ , Pb 2+ and Cu 2+ ) from aqueous solution. We investigated the adsorption capacity of Fe 3 O 4 -APS-AA-co-CA at different pH in solution and metal ion uptake capacity as a function of contact time and metal ion concentration. Moreover, adsorption isotherms, kinetics and thermodynamics were studied to understand the mechanism of the synthesized MNPs adsorbing metal ions. In addition, we evaluated the effect of background electrolytes on the adsorption. Furthermore, we explored desorption and reuse of MNPs. Fe 3 O 4 -APS-AA-co-CA MNPs are excellent for removal of heavy metal ions such as Cd 2+ , Zn 2+ , Pb 2+ and Cu 2+ from aqueous solution. Furthermore, the MNPs could efficiently remove the metal ions with high maximum adsorption capacity at pH 5.5 and could be used as a reusable adsorbent with convenient conditions.

Modified Fe{sub 3}O{sub 4}- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

Energy Technology Data Exchange (ETDEWEB)

Valizadeh, S., E-mail: valizadehsolmaz@yahoo.com; Rasoulifard, M.H., E-mail: m_h_rasoulifard@znu.ac.ir; Dorraji, M.S. Seyed, E-mail: dorraji@znu.ac.ir

2014-11-15

Graphical abstract: - Highlights: • Photocatalytic degradation of dye by Ag modified HAP under visible light. • Study of Fenton like degradation of dye by transition metal ions modified HAP. • Comparison of catalytic systems according to Langmuir-Hinshelwood kinetic expression. - Abstract: The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag{sub 3}PO{sub 4} formation. Apparent reaction rate constant (K{sub app}) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H{sub 2}O{sub 2}, Co-M-HAP(II)/H{sub 2}O{sub 2} and M-HAP (I)/UV systems, respectively.

Annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films

Energy Technology Data Exchange (ETDEWEB)

Alves, M. J. P.; Gonzalez-Chavez, D. E.; Sommer, R. L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

2015-03-28

We systematically investigate the annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films with thickness of 100 nm. We correlate the non-uniform residual stress obtained from grazing incidence x-ray diffraction measurements with the ferromagnetic resonance (FMR) linewidth due to effective field inhomogeneities measured from broadband ferromagnetic resonance absorption measurements. We also estimate the annealing temperature effect on the Gilbert and two-magnon scattering contributions to the total ferromagnetic resonance FMR linewidth. We show that the effective field inhomogeneities constitute the main contribution to the microwave linewidth, while this contribution is related to the non-uniform residual stress in the films which is reduced by thermal annealing.

Equilibrium Sorption studies of Fe, Cu and Co ions in aqueous ...

African Journals Online (AJOL)

Recinius Communis Linn a commonly found herbal plant was used to prepare activated carbon by physicochemical activation method. The sorption capacity of this bio-resource material to remove Fe(III), Cu(II) and Co(II) from aqueous solutions was determined by batch tests. The influences of important parameters such as ...

Theoretical investigation of image states of the hydrogen covered Cu (100)

International Nuclear Information System (INIS)

Steslicka, M.; Zagorski, M.; Jurczyszyn, L.

1987-08-01

A model of atomic hydrogen covered Cu(100) is presented and the calculated energy spectrum of localized electronic states in the X gap of Cu(100) is discussed. These states form a series of unoccupied adsorption image states (for n α = 2,3,...) lying below the vacuum level V 0 and having energies E nα which satisfy the formula E nα = V 0 - 10/n n 2 (eV). The lowest state (n α = 1) is expected to lie about 5.5 (eV) below Fermi level. (author). 19 refs, 6 figs, 1 tab

Magnetic Excitations in Weakly Coupled Spin Dimers and Chains Material Cu2Fe2Ge4O13

International Nuclear Information System (INIS)

Masuda, Takatsugu; Zheludev, Andrey I.; Sales, Brian C.; Imai, S.; Uchinokura, K.; Park, S.

2005-01-01

Magnetic excitations in a weakly coupled spin dimers and chains compound Cu 2 Fe 2 Ge 4 O 13 are measured by inelastic neutron scattering. Both structure factors and dipsersion of low-energy excitations up to 10 meV energy transfer are well described by a semiclassical spin wave theory involving interacting Fe 3+ (S=5/2) chains. Additional dispersionsless excitations are observed at higher energies, at ℎω=24 meV, and associated with singlet-triplet transitions within Cu 2+ dimers. Both types of excitations can be understood by treating weak interactions between the Cu 2+ and Fe 3+ subsystems at the level of the mean-field random phase approximation. However, this simple model fails to account for the measured temperature dependence of the 24 meV mode.

Effect of Cu addition on coercivity and interfacial state of Nd-Fe-B/Nd-rich thin films

International Nuclear Information System (INIS)

Matsuura, M; Sugimoto, S; Fukada, T; Tezuka, N; Goto, R

2010-01-01

This study provides the effect of Cu addition on coercivity (H cJ ) and interfacial microstructure in Nd-Fe-B/Nd-rich thin films. All films were deposited by using ultra high vacuum (UHV) magnetron sputtering, and the Nd-Fe-B layer was oxidized under several atmospheres with different oxygen content. Then, the films were annealed at 250-550 0 C under UHV. The films oxidized in low vacuum (10 -2 -10 -5 Pa) (under low oxygen state) exhibited the recovery of H cJ by the annealing at 450 0 C. On the contrary, the H cJ of the films oxidized in Ar (under high oxygen state) decreased with increasing annealing temperature. However, the H cJ increased drastically at the temperatures above 550 0 C. In addition, the Cu added films, which were annealed at temperatures above 350 0 C, showed higher coercivities than the films without Cu addition. The XRD analysis suggested the existence of C-Nd 2 O 3 phase in the Cu added films annealed at 550 0 C. It can be considered that the Cu addition decreases the eutectic temperature of Nd-rich phase and influences the interfacial state between Nd 2 Fe 14 B and Nd-rich phase.

Experiment and simulation on the thermal instability of a heavily deformed Cu-Fe composite

International Nuclear Information System (INIS)

Qu Lei; Wang Engang; Zuo Xiaowei; Zhang Lin; He Jicheng

2011-01-01

Research highlights: → Fe fibers undergo thermal instability at temperature above 600 deg. C. → Longitudinal boundary splitting is the dominant instability process. → Instability of cylindrical fibers is controlled by breakup, growth and coarsening. → Breakup times can be predicted by Rayleigh perturbation model accurately. → The increase of fiber diameters is due to the coarsening and growth. - Abstract: The thermal instability of the Fe fibers in the heavily deformed Cu-12.8 wt.%Fe composites is investigated experimentally and numerically. The fiber evolution is characterized by a field emission scanning electron microscopy (FESEM). The results show that the dominant instability of the Fe fibers is the longitudinal boundary splitting which is determined by the greater cross sectional aspect ratio (width/thickness, w/t) and the larger ratio of boundary to interfacial energy (γ B /γ S ). The longitudinal boundary splitting makes the ribbon-like Fe fibers evolve into a series of cylindrical fibers. Then the cylindrical Fe fibers undergo the instability process in terms of the breakup, growth and coarsening concurrently. The breakup times are accurately predicted by the Rayleigh perturbation model. The growth process primarily contributes to the higher increasing rate of the fiber radius during isothermal annealing at 700 deg. C than that calculated by the coarsening theory developed for cylindrical fibers, since the Cu-matrix of composites is highly supersaturated after casting/cold-working process.

Carbon disulfide (CS{sub 2}) adsorption and dissociation on the Cu(100) surface: A quantum chemical study

Energy Technology Data Exchange (ETDEWEB)

Wang, Wenju, E-mail: wangwenju1982@163.com; Fan, Lili; Wang, Guoping, E-mail: wgp1976@163.com

2017-08-31

Highlights: • CS{sub 2}, CS, C and S are strongly chemadsorbed on the Cu(100) surface. • C/S/S, S/CS and CS{sub 2} accord to a decreased adsorption strength on the Cu(100). • The asymmetric model CS{sub 2}(II) is easier to dissociate on the Cu(100) surface. - Abstract: Density functional theory (DFT) is used to examine the adsorption and dissociation of CS{sub 2} on the Cu(100) surface. This study evaluates the adsorption energies and geometries of the species (CS{sub 2}, CS, C and S) adsorption on the Cu(100) surface, as well as that coadsorption of CS and a S atom, and that coadsorption of C atom and two S atoms. The results indicate that the species (CS{sub 2}, CS, C and S) are strongly chemadsorbed on the Cu(100) surface through the C−Cu and/or S−Cu bond with an increased adsorption energy (C/S/S > S/CS > CS{sub 2}). Two pathways for CS{sub 2} dissociation on the Cu(100) surface are constructed, and the energy barrier and reaction energy of each step are calculated. It shows that the dissociated energy barrier of the second C−S bond is 0.25 eV higher than that of the first C−S bond in the pathway 1, but in the pathway 2, the dissociated energy barrier of the second C−S bond is 0.11 eV lower than that of the first C−S bond. Comparing the highest dissociated energy barrier of pathway 1 (0.68 eV) and pathway 2 (0.5 eV), the structure of S/C/S(II) is regarded as a preferable product for the dissociation of CS{sub 2} on the Cu(100) surface.

Moessbauer study of isothermally annealed amorphous Fe-Nb-Cu-Si-B alloys

Energy Technology Data Exchange (ETDEWEB)

Sitek, J. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Toth, I. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Miglierini, M. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia))

1993-11-01

Amorphous ribbons of Fe[sub 73.5]Nb[sub 3]Cu[sub 1]Si[sub 13.5]B[sub 9] have been annealed above the crystallization temperature. Annealed samples consisted of crystalline and amorphous phases in a wide temperature range. Two samples of different thicknesses of 33 [mu]m and 27 [mu]m were isothermally annealed at a temperature of 545 C from 0.5 to 5 h in a vacuum furnace. The amount of crystalline phase increases rapidly in the ticker sample. The crystalline part of the Moessbauer spectrum consists of four sharp sextets which can be assigned to a DO[sub 3]-structure FeSi alloy. After 700 C annealing the amorphous phase was not observed and the crystalline phase consisted of the DO[sub 3]-structure FeSi alloy, paramagnetic FeNbB and presumably Fe[sub 23]B[sub 6] and Fe[sub 3]SiB[sub 2]. (orig.)

Controllably annealed CuO-nanoparticle modified ITO electrodes: Characterisation and electrochemical studies

Energy Technology Data Exchange (ETDEWEB)

Wang, Tong; Su, Wen; Fu, Yingyi [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Hu, Jingbo, E-mail: hujingbo@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China)

2016-12-30

Graphical abstract: We report a simple and controllable synthesis of CuO-nanoparticle-modified ITO by employing a combination of ion-implantation and annealing methods for the first time. The optimum CuO/ITO electrode shows uniform morphology, highly accessible surface area, long-term stability and excellent electrochemical performance towards biomolecules such as glucose in alkaline solution. - Highlights: • Controllably annealed CuO/ITO electrode was synthesized for the first time. • The generation mechanism of CuO nanoparticles is revealed. • The optimum CuO/ITO electrode shows excellent electrochemical performance. • A reference for the controllable preparation of other metal oxide nanoparticles. - Abstract: In this paper, we report a facile and controllable two-step approach to produce indium tin oxide electrodes modified by copper(II) oxide nanoparticles (CuO/ITO) through ion implantation and annealing methods. After annealing treatment, the surface morphology of the CuO/ITO substrate changed remarkably and exhibited highly electroactive sites and a high specific surface area. The effects of annealing treatment on the synthesis of CuO/ITO were discussed based on various instruments’ characterisations, and the possible mechanism by which CuO nanoparticles were generated was also proposed in this work. Cyclic voltammetric results indicated that CuO/ITO electrodes exhibited effective catalytic responses toward glucose in alkaline solution. Under optimal experimental conditions, the proposed CuO/ITO electrode showed sensitivity of 450.2 μA cm{sup −2} mM{sup −1} with a linear range of up to ∼4.4 mM and a detection limit of 0.7 μM (S/N = 3). Moreover, CuO/ITO exhibited good poison resistance, reproducibility, and stability properties.

Friction and wear properties of Cu and Fe-based P/M bearing materials

International Nuclear Information System (INIS)

Tufekci, Kenan; Kurbanoglu, Cahit; Durak, Ertugrul; Tunay, R. Fatih

2006-01-01

The performances of porous bearings under different operating conditions were experimentally investigated in this study. Material groups studied are 90%Cu + 10%Sn bronze and 1%C + % balance Fe iron-based self-lubricating P/M bearings at constant (85%) density. In the experiments, the variation of the coefficient of friction and wear ratio of those two different group materials for different sliding speeds, loads, and temperatures were investigated. As a result, the variation of the friction coefficient - temperature for both constant load, and constant sliding speed, friction coefficient - average bearing pressure, PV - wear loss and temperature-wear loss curves were plotted and compared with each other for two materials, separately. The test results showed that Cu-based bearings have better friction and wear properties than Fe-based bearings

The improvement of the superconducting Y-Ba-Cu-O magnet characteristics through shape recovery strain of Fe-Mn-Si alloys

International Nuclear Information System (INIS)

Shimpo, Y.; Seki, H.; Wongsatanawarid, A.; Taniguchi, S.; Maruyama, T.; Kurita, T.; Murakami, M.

2010-01-01

Since bulk Y-Ba-Cu-O superconductors are brittle ceramics, reinforcement of mechanical properties is important for practical applications. It has been reported that bulk Y-Ba-Cu-O can be reinforced with Al or Fe based alloy ring, in that compression force acts on bulk Y-Ba-Cu-O due to a difference in thermal expansion coefficients. However, the shrinkage of the metal ring was not so large, and therefore careful adjustment of the circumference of the bulk and the metal rings was necessary. In this study, we employed Fe-Mn-Si shape memory alloy rings to reinforce bulk Y-Ba-Cu-O. The advantage of the shape memory alloy is that the shrinkage can take place on heating, and furthermore, the alloy shrinks and compresses the bulk body on cooling. Bulk Y-Ba-Cu-O superconductor 22.8 mm in diameter was inserted in a Fe-Mn-Si ring 23.0 mm in inner diameter at room temperature. Beforehand, the Fe-Mn-Si ring was expanded by 12% strain at room temperature. Then the composite was heated to 673 K. At room temperature, the Fe-Mn-Si ring firmly gripped the bulk superconductor. We then measured trapped fields before and after the ring reinforcement, and found that the trapped field was improved through the treatment.

Fabrication of core-shell Fe{sub 3}O{sub 4}@MIL-100(Fe) magnetic microspheres for the removal of Cr(VI) in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Yang, Qingxiang, E-mail: qxyangzz@163.com; Zhao, Qianqian; Ren, ShuangShuang; Lu, Qiongqiong; Guo, Xinmeng; Chen, Zhijun, E-mail: chenzj@zzuli.edu.cn

2016-12-15

Facile regeneration of an adsorbent is very important for commercial feasibility. One typical highly porous metal-organic framework (MOF) materials based on MIL-100(Fe) and magnetic iron oxide particles (denoted as MMCs) with diameter about of 350 nm were successfully synthesized. The growth of MIL-100(Fe) shell on the surface of Fe{sub 3}O{sub 4} was utilized precursor as crystal seed via in-situ step hydrothermal reaction. It is a simple way to obtain well organized core-shell MOF composites, compared to the step-by-step method. MMCs were firstly used to uptake of Cr(VI) anions in aqueous solution. Adsorption experiments were carried out in batch sorption mode investigating with the factors of contact time (0–1000 min), pH (from 2 to 12), dose of adsorbent (4–25 mg), and initial Cr(VI) concentration (range from 10 to 100 ppm). - Graphical abstract: One typical highly porous metal-organic framework (MOF) materials based on MIL-100(Fe) and magnetic iron oxide particles (denoted as MMCs) were successfully synthesized. Utilizing Fe{sub 3}O{sub 4} precursor as crystal seed to grow MIL-100(Fe) shell by in-situ step hydrothermal reaction. It is a simple way to obtain core-shell MOF composites. MMCs could effectively uptake of Cr(VI) anions in aqueous solution. - Highlights: • Fe{sub 3}O{sub 4}@MIL-100(Fe) composites with core-shell structure were successfully prepared through a simple method. • The influence factors on Cr(VI) adsorption by Fe{sub 3}O{sub 4}@MIL-100(Fe) were investigated. • Cr(VI) can efficiently adsorbed by Fe{sub 3}O{sub 4}@MIL-100(Fe) composites from aqueous solution.

Synthesis of Fe–Cu/TiO2 nanostructure and its use in construction of a sensitive and selective sensor for metformin determination

International Nuclear Information System (INIS)

Gholivand, Mohammad Bagher; Shamsipur, Mojtaba; Paimard, Giti; Feyzi, Mostafa; Jafari, Fataneh

2014-01-01

A carbon paste electrode modified with Fe-Cu/TiO 2 was prepared and used for low level determination of metformin (MET) using square wave adsorptive stripping voltammetry (SWAdSV). The Fe-Cu/TiO 2 nanoparticle was synthesized by a modified sol–gel method. The surface structure and composition of nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction analysis (XRD) and N 2 physisorption. Also, electrochemical properties of the prepared nanocomposite modified electrode were investigated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques. Under optimized conditions, the modified electrode exhibited a linear response over the concentration range of 15 nM to 75 μM MET, with a detection limit of 3 nM. The proposed sensor exhibited a high sensitivity, good selectivity and was successfully applied for MET determination in real samples such as human urine and pharmaceutical formulations. - Highlights: • A carbon paste modified electrode for determination of MET was developed. • The synthesized Fe-Cu/TiO 2 nanocomposite was used as a modifier. • The sensor was successfully applied for MET determination in real samples. • Square wave adsorptive stripping voltammetric method was used for MET determination

Sintered powder cores of high Bs and low coreloss Fe84.3Si4B8P3Cu0.7 nano-crystalline alloy

Directory of Open Access Journals (Sweden)

Yan Zhang

2013-06-01

Full Text Available Nano-crystalline Fe-rich Fe84.3Si4B8P3Cu0.7 alloy ribbon with saturation magnetic flux density (Bs close to Si-steel exhibits much lower core loss (Wt than Si-Steels. Low glass forming ability of this alloy limits fabrication of magnetic cores only to stack/wound types. Here, we report on fabrication, structural, thermal and magnetic properties of bulk Fe84.3Si4B8P3Cu0.7 cores. Partially crystallized ribbons (obtained after salt-bath annealing treatment were crushed into powdered form (by ball milling, and were compacted to high-density (∼88% bulk cores by spark plasma sintering (SPS. Nano-crystalline structure (consisting of α-Fe grain in remaining amorphous matrix similar to wound ribbon cores is preserved in the compacted cores. At 50 Hz, cores sintered at Ts = 680 K show Wt 1 kHz. A trade-off between porosity and electrical resistivity is necessary to get low Wt at higher f. In the f range of ∼1 to 100 kHz, we have shown that the cores mixed with SiO2 exhibit much lower Wt than Fe-powder cores, non-oriented Si-steel sheets and commercially available sintered cores. We believe our core material is very promising to make power electronics/electrical devices much more energy-efficient.

Magnetization reversal of a Nd-Cu-infiltrated Nd-Fe-B nanocrystalline magnet observed with small-angle neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Saito, Kotaro, E-mail: kotaro.saito@kek.jp; Ono, Kanta [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, 305-0803 Tsukuba (Japan); Ueno, Tetsuro [Elements Strategy Initiative Center for Magnetic Materials, National Institute for Materials Science, 1-2-1 Sengen, 305-0047 Tsukuba (Japan); Yano, Masao; Shoji, Tetsuya; Sakuma, Noritsugu; Manabe, Akira; Kato, Akira [Toyota Motor Corporation, Toyota, Aichi 471-8571 (Japan); Harada, Masashi [Toyota Central R and D Labs, Inc., Aichi 480-1192 (Japan); Keiderling, Uwe [Helmholtz-Zentrum Berlin für Materialien and Energie, 14109 Berlin (Germany)

2015-05-07

The magnetization reversal process of Nd-Fe-B nanocrystalline magnets infiltrated with Nd-Cu alloy was examined using small-angle neutron scattering (SANS). The magnetic-field dependence of SANS intensity revealed a qualitative difference between Nd-Cu-infiltrated samples and as-deformed samples. Insufficient magnetic isolation along the direction perpendicular to the nominal c-axis is expected from comparable SANS intensities for different ranges of q values along this direction. For small q values near the coercivity field, Nd-Cu-infiltrated samples show a noticeable reduction in SANS intensity along the nominal c-axis, which is parallel to the external magnetic field. This indicates less spatial fluctuation of magnetic moments in Nd-Cu-infiltrated samples, owing to magnetically isolated Nd{sub 2}Fe{sub 14}B grains.

Magnetization reversal of a Nd-Cu-infiltrated Nd-Fe-B nanocrystalline magnet observed with small-angle neutron scattering

International Nuclear Information System (INIS)

Saito, Kotaro; Ono, Kanta; Ueno, Tetsuro; Yano, Masao; Shoji, Tetsuya; Sakuma, Noritsugu; Manabe, Akira; Kato, Akira; Harada, Masashi; Keiderling, Uwe

2015-01-01

The magnetization reversal process of Nd-Fe-B nanocrystalline magnets infiltrated with Nd-Cu alloy was examined using small-angle neutron scattering (SANS). The magnetic-field dependence of SANS intensity revealed a qualitative difference between Nd-Cu-infiltrated samples and as-deformed samples. Insufficient magnetic isolation along the direction perpendicular to the nominal c-axis is expected from comparable SANS intensities for different ranges of q values along this direction. For small q values near the coercivity field, Nd-Cu-infiltrated samples show a noticeable reduction in SANS intensity along the nominal c-axis, which is parallel to the external magnetic field. This indicates less spatial fluctuation of magnetic moments in Nd-Cu-infiltrated samples, owing to magnetically isolated Nd 2 Fe 14 B grains

Spectrophotometric analysis of vitamin E using Cu(I)-Bathocuproine or/and Fe(II)-2,4,6-tris-(2'-pyridyl)-s-triazine complexes

International Nuclear Information System (INIS)

Devi, I.; Memon, S. A.; Khuhawar, M.Y.

2004-01-01

Vitamin E (tocopherols and tocotrienols) antioxidants are determined by reducing Cu(II) to Cu(I) or Fe(III) to Fe(II) in presence of vitamin E and subsequent complexation of Cu(I) with bathocuproine and/or Fe(II) with 2,4,6-tris-(2'-pyridyl)-s-triazine (TPTZ). Both the reactions are monitored separately, Cu(I)-bathocuproine at 479 nm where as, Fe(II)-(TPTZ) at 595 nm spectrophotometrically. Linear calibration curves are achieved for both complexes between I to 5mu g ml-1 for vitamin E. The methods were applied for the determination of vitamin E in pharmaceutical preparations and edible oils. Vitamin E, from edible oils, was solvent extracted into n-hexane prior to saponification. Furthermore, a single lined flow was also examined. A larger excess of Cu(II) or Fe =(II) with different concentrations of vitamin E in buffer pH 4 was run on the line and constant amounts of reagent bathocuproine or TPTZ in each case was injected through the injector. The peak height shows a linear relationship for vitamin E between 0.5 to 2.5 mu g ml-1 for both complexes. (author)

Magnetically separable CuFe{sub 2}O{sub 4}/AgBr composite photocatalysts: Preparation, characterization, photocatalytic activity and photocatalytic mechanism under visible light

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yalei; Lin, Cuiping; Bi, Huijie; Liu, Yonggang; Yan, Qishe, E-mail: Qisheyanzzu@163.com

2017-01-15

Highlights: • CuFe{sub 2}O{sub 4}/AgBr composites were prepared by a facile sol-gel and hydrothermal method. • Visible-light response and high photocatalytic performance. • Excellent magnetic properties. • Different reactive species had different effects on degradation different pollutants. - Abstract: The CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4}/AgBr composites with different CuFe{sub 2}O{sub 4} contents were prepared by a facile sol-gel and hydrothermal method, respectively. The as-synthesized photocatalysts were characterized by means of powder X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectrum (UV–vis DRS). Their magnetic properties, photocatalytic degradation activities on methyl orange (MO) and tetracycline hydrochloride (TC) solution and photocatalytic mechanism were investigated in detail. The results revealed that the CuFe{sub 2}O{sub 4}/AgBr composites exhibited significantly higher photocatalytic activities than the pure CuFe{sub 2}O{sub 4}. The enhanced photocatalytic activity could be attributed to the matched band structure of two components and more effective charge transportation and separations. In addition, the quenching investigation of different scavengers demonstrated that h{sup +}, ·OH, ·O{sub 2}{sup −} reactive species played different roles in the decolorization of MO and degradation of TC.

Two-dimensional nano-lattice in Fe-Co-Ni-Al-Cu alloys

International Nuclear Information System (INIS)

Kalanov, M.U.; Ibragimova, E.M.; Khamraeva, R.N.; Rustamova, V.M.; Ummatov, H.D.

2007-01-01

Full text: The high coercive strength of the dispersionally solidified alloys on the base of Fe-Co-Ni-Al-Cu system appears as a result of the special thermomagnetic annealing, when particles of the strong magnetic phase are distinguished in non-magnetic matrix along an external magnetic field direction. The neutron studying allows one to reveal the correlation between magnetization and inclusion axes, and also existence of magnetic microcell and perfectness of the lattice. This work presents results of neutron diffraction study with a double-crystal spectrometer (0.145 nm). Plate like samples of size 18 12 4 mm 3 were cut from a single crystal of alloy UNDK35 T5 along (100) plane. Magnetic field of 6 kOe was applied perpendicular to the neutron beam. Zero-field spectrum had only random variation of the background. Under the applied magnetic field two maxima appeared at the angles of 12 and 24 minute. In the case of the magnetic field directed in parallel to the scattering vector, the two maxima disappeared as expected. It is evidence that nuclear scattering is less than magnetic one and the observed maxima correspond to (10) and (20) reflections from a two dimensional ferro-magnetic microcell. The cell parameter of the magnetic microcell was found 40.6 nm. The coherent scattering region size was 120-160 nm. The ferro-magnetic rod diameter estimated from the peak widths was 16 nm. The diffraction pattern for the demagnetized sample strongly differs from the initial magnetized sample, where a diffuse reflection was observed near Bragg reflection and related with residual magnetization. So, the magnetic inclusions created in the Fe-Co-Ni-Al-Cu system at the thermomagnetic annealing by means of disintegration of the solid solution are strong ferro-magnetic and one-domain. These particles form the two-dimensional magnetic microcell and interact each to other within 3-4 periods of the cell. (authors)

Microstructure and Magnetic Properties of Fe and Fe-alloy Thin Films Epitaxially Grown on MgO(100) Substrates

Energy Technology Data Exchange (ETDEWEB)

Matsubara, Katsuki; Ohtake, Mitsuru; Futamoto, Masaaki [Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Kirino, Fumiyoshi, E-mail: matsubara@futamoto.elect.chuo-u.ac.jp [Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music, 12-8 Ueno-koen, Taito-ku, Tokyo 110-8714 (Japan)

2011-07-06

Fe, Fe{sub 50}Co{sub 50}, and Fe{sub 80}Ni{sub 20} (at. %) single-crystal films with the (100){sub bcc} plane parallel to the substrate surface were prepared on MgO(100) single-crystals heated at 300 {sup 0}C by ultra high vacuum molecular beam epitaxy. The film growth mechanism, the film structure, and the magnetic properties were investigated. In-situ reflection high energy electron diffraction and X-ray diffraction analyses indicate that the strains in the films are very small though there are fairly large mismatches of -3.7{approx}-4.3% at the film/substrate interface. Cross-sectional high-resolution transmission electron microscopy shows that misfit dislocations are introduced in the film at the interface. Dislocations are also observed in the film up to around 10{approx}20 nm distance from the interface. The presence of such dislocation relieves the strain caused by the lattice mismatch. The in-plane magnetization properties of these films reflect the magnetocrystalline anisotropies of respective bulk Fe, Fe{sub 50}Co{sub 50}, and Fe{sub 80}Ni{sub 20} crystals.

Microstructure and Magnetic Properties of Fe and Fe-alloy Thin Films Epitaxially Grown on MgO(100) Substrates

International Nuclear Information System (INIS)

Matsubara, Katsuki; Ohtake, Mitsuru; Futamoto, Masaaki; Kirino, Fumiyoshi

2011-01-01

Fe, Fe 50 Co 50 , and Fe 80 Ni 20 (at. %) single-crystal films with the (100) bcc plane parallel to the substrate surface were prepared on MgO(100) single-crystals heated at 300 0 C by ultra high vacuum molecular beam epitaxy. The film growth mechanism, the film structure, and the magnetic properties were investigated. In-situ reflection high energy electron diffraction and X-ray diffraction analyses indicate that the strains in the films are very small though there are fairly large mismatches of -3.7∼-4.3% at the film/substrate interface. Cross-sectional high-resolution transmission electron microscopy shows that misfit dislocations are introduced in the film at the interface. Dislocations are also observed in the film up to around 10∼20 nm distance from the interface. The presence of such dislocation relieves the strain caused by the lattice mismatch. The in-plane magnetization properties of these films reflect the magnetocrystalline anisotropies of respective bulk Fe, Fe 50 Co 50 , and Fe 80 Ni 20 crystals.

Theoretical studies of positron states and annihilation characteristics at the oxidized Cu(100) surface

Energy Technology Data Exchange (ETDEWEB)

Fazleev, N. G. [Department of Physics, Box 19059, University of Texas at Arlington, Arlington Texas 76019 (United States) and Institute of Physics, Kazan Federal University, Kremlevskaya18, Kazan 420008 (Russian Federation); Weiss, A. H. [Department of Physics, Box 19059, University of Texas at Arlington, Arlington Texas 76019 (United States)

2013-04-19

In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. An ab-initio study of the electronic properties of the Cu(100) missing row reconstructed surface at various on surface and sub-surface oxygen coverages has been performed on the basis of the density functional theory (DFT) using the Dmol3 code and the generalized gradient approximation (GGA). Surface structures in calculations have been constructed by adding oxygen atoms to various surface hollow and sub-surface octahedral sites of the 0.5 monolayer (ML) missing row reconstructed phase of the Cu(100) surface with oxygen coverages ranging from 0.5 to 1.5 ML. The charge redistribution at the surface and variations in atomic structure and chemical composition of the topmost layers associated with oxidation and surface reconstruction have been found to affect the spatial extent and localization of the positron surface state wave function and annihilation probabilities of surface trapped positrons with relevant core electrons. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES). It has been shown that positron annihilation probabilities with Cu 3s and 3p core electrons decrease when total (on-surface and sub-surface) oxygen coverage of the Cu(100) surface increases up to 1 ML. The calculations show that for high oxygen coverage when total oxygen coverage is 1. 5 ML the positron is not bound to the surface.

First-principles-based study of transport properties of Fe thin films on Cu surfaces

Energy Technology Data Exchange (ETDEWEB)

Kishi, Tomoya [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Kasai, Hideaki [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Nakanishi, Hiroshi [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Dino, Wilson Agerico [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Komori, Fumio [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8587 (Japan)

2004-12-08

We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties.

First-principles-based study of transport properties of Fe thin films on Cu surfaces

International Nuclear Information System (INIS)

Kishi, Tomoya; Kasai, Hideaki; Nakanishi, Hiroshi; Dino, Wilson Agerico; Komori, Fumio

2004-01-01

We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties