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Sample records for metals cr cu

  1. Brazing of Be with CuCrZr-bronze using copper-based filler metal STEMET

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    B.A. Kalin

    2016-12-01

    Optimization of the composition of the Cu–Ni–Sn–P system filler metals and comparative tests of filler metals of various compositions have been carried out in this paper to reduce the brazing temperature of beryllium with CuCrZr. Alloys of the following compositions Cu–6.4Ni–9.2Sn–6.3P (STEMET 1105 and Cu–9.1Ni–3.6Sn–8.0P (STEMET 1101 were made in the form of rapidly quenched ribbons with a thickness of 50µm and a width of 50mm. They were used to perform furnace brazing by Joule heating (with a rate of 15K/min of beryllium with CuCrZr (Be/CuCrZr at temperatures of 650, 700 and 750°C for 15min. Metallographic investigations of the zone of brazing and mechanical shear tests of joints before and after the heat treatment at 350°C for 30h have been conducted. It was found that the joints of Be/CuCrZr brazed at 650°C using STEMET 1105 (τs=230MPa and at 750°C using STEMET 1101 (τs=260MPa had the best shear strength properties. However, there is a significant decrease of the microhardness of CuCrZr from 1570 to 1140MPa at 750°C, which indicates a significant loss of its strength. The results obtained suggest that the brazing of beryllium with CuCrZr using STEMET 1105 at 650–700°C will not adversely affect the CuCrZr.

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

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

    2016-10-01

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

  3. Half-metallic antiferromagnetism in double perovskite BiPbCrCuO{sub 6}

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    Weng, Ke-Chuan [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Wang, Y. K., E-mail: kant@ntnu.edu.tw [Center for General Education and Department of Physics, National Taiwan Normal University, Taipei 106, Taiwan (China)

    2015-05-07

    The electronic structure and magnetic properties of BiPbCrCuO{sub 6} double perovskite are investigated based on first-principles density functional calculations with generalized gradient approximation (GGA) and GGA incorporated with Coulomb correlation interaction U (GGA + U). The results suggest the half-metallic (HM) and antiferromagnetic (AFM) properties of BiPbCrCuO{sub 6} double perovskite. The HM-AFM property of the double perovskite is caused by the double-exchange mechanism between neighboring Cr{sup 5+}(t{sub 2g}{sup 1}↓) and Cu{sup 2+}(t{sub 2g}{sup 3}↑t{sub 2g}{sup 3}↓e{sub g}{sup 2}↑e{sub g}↓) via the intermediate O{sup 2−}(2s{sup 2}2p{sup 6}) ion.

  4. Preliminary assessment of metal-porcelain bonding strength of CoCrW alloy after 3wt.% Cu addition.

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    Lu, Yanjin; Zhao, Chaoqian; Ren, Ling; Guo, Sai; Gan, Yiliang; Yang, Chunguang; Wu, Songquan; Lin, Junjie; Huang, Tingting; Yang, Ke; Lin, Jinxin

    2016-06-01

    In this work, a novel Cu-bearing CoCrW alloy fabricated by selective laser melting for dental application has been studied. For its successful application, the bonding strength of metal-porcelain is essential to be systematically investigated. Therefore, the aim of this study was to evaluate the metal-porcelain bonding strength of CoCrWCu alloy by three-point bending test, meanwhile the Ni-free CoCrW alloy was used as control. The oxygen content was investigated by an elemental analyzer; X-ray photoelectron spectroscopy (XPS) was used to analyze the surface chemical composition of CoCrW based alloy after preoxidation treatment; the fracture mode was investigated by X-ray energy spectrum analysis (EDS) and scanning electron microscope (SEM). Result from the oxygen content analysis showed that the content of oxygen dramatically increased after the Cu addition. And the XPS suggested that Co-oxidation, Cr2O3, CrO2, WO3, Cu2O and CuO existed on the preoxidated surface of the CoCrWCu alloy; the three-point bending test showed that the bonding strength of the CoCrWCu alloy was 43.32 MPa, which was lower than that of the CoCrW group of 47.65 MPa. However, the average metal-porcelain bonding strength is significantly higher than the minimum value in the ISO 9693 standard. Results from the SEM images and EDS indicated that the fracture mode of CoCrWCu-porcelain was mixed between cohesive and adhesive. Based on the results obtained in this study, it can be indicated that the Cu-bearing CoCrW alloy fabricated by the selective laser melting is a promising candidate for use in dental application.

  5. Electroless deposition of NiCrB diffusion barrier layer film for ULSI-Cu metallization

    Science.gov (United States)

    Wang, Yuechun; Chen, Xiuhua; Ma, Wenhui; Shang, Yudong; Lei, Zhengtao; Xiang, Fuwei

    2017-02-01

    NiCrB films were deposited on Si substrates using electroless deposition as a diffusion barrier layer for Cu interconnections. Samples of the prepared NiCrB/SiO2/Si and NiCrB/Cu/NiCrB/SiO2/Si were annealed at temperatures ranging from 500 °C to 900 °C. The reaction mechanism of the electroless deposition of the NiCrB film, the failure temperature and the failure mechanism of the NiCrB diffusion barrier layer were investigated. The prepared samples were subjected to XRD, XPS, FPP and AFM to determine the phases, composition, sheet resistance and surface morphology of samples before and after annealing. The results of these analyses indicated that the failure temperature of the NiCrB barrier film was 900 °C and the failure mechanism led to crystallization and grain growth of the NiCrB barrier layer after high temperature annealing. It was found that this process caused Cu grains to reach Si substrate through the grain boundaries, and then the reaction between Cu and Si resulted in the formation of highly resistive Cu3Si.

  6. Preliminary assessment of metal-porcelain bonding strength of CoCrW alloy after 3 wt.% Cu addition

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanjin; Zhao, Chaoqian [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China); Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Guo, Sai; Gan, Yiliang [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China); Yang, Chunguang [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Wu, Songquan; Lin, Junjie; Huang, Tingting [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Lin, Jinxin, E-mail: franklin@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China)

    2016-06-01

    In this work, a novel Cu-bearing CoCrW alloy fabricated by selective laser melting for dental application has been studied. For its successful application, the bonding strength of metal-porcelain is essential to be systematically investigated. Therefore, the aim of this study was to evaluate the metal-porcelain bonding strength of CoCrWCu alloy by three-point bending test, meanwhile the Ni-free CoCrW alloy was used as control. The oxygen content was investigated by an elemental analyzer; X-ray photoelectron spectroscopy (XPS) was used to analyze the surface chemical composition of CoCrW based alloy after preoxidation treatment; the fracture mode was investigated by X-ray energy spectrum analysis (EDS) and scanning electron microscope (SEM). Result from the oxygen content analysis showed that the content of oxygen dramatically increased after the Cu addition. And the XPS suggested that Co-oxidation, Cr{sub 2}O{sub 3}, CrO{sub 2}, WO{sub 3}, Cu{sub 2}O and CuO existed on the preoxidated surface of the CoCrWCu alloy; the three-point bending test showed that the bonding strength of the CoCrWCu alloy was 43.32 MPa, which was lower than that of the CoCrW group of 47.65 MPa. However, the average metal-porcelain bonding strength is significantly higher than the minimum value in the ISO 9693 standard. Results from the SEM images and EDS indicated that the fracture mode of CoCrWCu-porcelain was mixed between cohesive and adhesive. Based on the results obtained in this study, it can be indicated that the Cu-bearing CoCrW alloy fabricated by the selective laser melting is a promising candidate for use in dental application. - Highlights: • The bonding strength of metal-porcelain was slightly decreased with Cu addition; • Cu not only led to promote the diffusion of O and W element but also inhibited the diffusivity of Co in the outward direction; • The changed oxidation behavior resulted in lowering the bonding strength;.

  7. First-Principles Study of Doped Half-Metallic Spinels: Cu0.5Zn0.5Cr2S4,Cu0.5Cd0.5Cr2S4, Li0.5Zn0.5Cr2O4 and Li0.5Zn0.5Cr2S4

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tie-Ge; LIU Zhi-Qiang; ZUO Xu

    2012-01-01

    Electronic structure and magnetic properties of Cu0.5 Zn0.5 Cr2S4, Cu0.5 Cd0.5 CrS4, Li0.5 Zn0.5 CrO4 and Li0.5 Zn0.5 Cr2S4 are investigated using the first-principles calculation based on the density functional theory. GGA+U exchange correlation is used in the calculation to correct the effective Coulomb repulsion energy of Cr underestimated by LSDA or GGA. The calculation results reveal that half-metallic Cu0.5 Zn0.5 Cr2S4 and Cu0.5 Cd0.5 CrS4 can be achieved by doping CuCr2S4 with Zn or Cd, though CuCr2S4 is not half-metallic. Half-metallic LiCr2O4 is experimentally unstable, but half-metallic Li0.5 Zn0.5 Cr2O4 and Li0.5 Zn0.5 Cr2S4 can be achieved by doping Li into experimentally stable ZnCr2O4 and ZnCr2S4, though ZnCr2O4 and ZnCr2S4 are not half-metallic. The influence of +U on the electronic structure and half-metallicity of the doped systems is also presented.%Electronic structure and magnetic properties of Cu0.5 Zn0.5 Cr2S4,Cu0.5 5 Cd0.5 Cr2S4,Li0.5 Zn0.5 Cr2O4 and Li0.5 Zn0.5 Cr2S4 are investigated using the first-principles calculation based on the density functional theory.GGA +U exchange correlation is used in the calculation to correct the effective Coulomb repulsion energy of Cr underestimated by LSDA or GGA.The calculation results reveal that half-metallic Cu0.5Zn0.5Cr2S4 and Cu0.5Cd0.5Cr2S4 can be achieved by doping CuCr2S4 with Zn or Cd,though CuCr2S4 is not half-metallic.Half-metallic LiCr2O4 is experimentally unstable,but half-metallic Li0.5Zn0.5 Cr2O4 and Li0.5Zn0.5 Cr2S4 can be achieved by doping Li into experimentally stable ZnCr2O4 and ZnCr2S4,though ZnCr2O4 and ZnCr2S4 are not half-metallic.The influence of +U on the electronic structure and half-metallicity of the doped systems is also presented.

  8. The efficiency of biosynthesis silica nanoparticles at removal of heavy metals Cr and Cu from aqueous solutions

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    Mohammad Hossein Sayadi

    2017-05-01

    Full Text Available Background and Aim: Nanotechnology considered as one of the main management strategy in reducing negative effects of water pollution, which leads to treating of water inexpensive and more effective. This study aimed to investigate the removal of Cr and Cu from aqueous solutions using nano-silicate which is synthesized by rice husk. Materials and Methods: In the present study, functionalized nano-silica with rice husk was fabricated and characterized by FT-IR، TEM, SEM and XRD. The effect of adsorbent dosage, initial concentration and equilibrium of chromium and copper and contact time in removal of mentioned heavy metals were investigated. Finally, the adsorption isotherms were analyzed. Results: The silica nanoparticles had nearly spherical morphology with a uniform size of about 80 nm. However, the obtained functionalized silica nanoparticles were spherical (about 90 nm in diameter. Results showed that optimum adsorption of Cr and Cu contaminant obtained at 100 minutes, while the optimum amount of adsorbent for Cr and Cu were 125 and 100 mg respectively. The optimal concentration of Cr and Cu was 2 mg/l. The correlation coefficients of adsorption isotherms of Cr (R2Langmuir =0.9946 and Cu (R2Langmuir =0.999 showed the good agreement between the adsorption data and Langmuir model. Conclusion: The study showed that the silica nanoparticles can be produced using agricultural waste as a inexpensive and environmentally friendly method and can be used to removing of contaminants from the aquatic environment.

  9. Bond strength of W-Cu/CuCr integrated material

    Institute of Scientific and Technical Information of China (English)

    范志康; 梁淑华; 薛旭

    2001-01-01

    The bond strength of W-Cu/CuCr integrated material was investigated. The results show that the fracture of W-Cu/CuCr integrated material often takes place at W-Cu/CuCr interface. Some alloying elements enhance the bond of W and CuCr alloy, which results in the increase of the strength of the W-Cu/CuCr interface. And the fracture of the WCu/CuCr integrated material occurs in the CuCr alloy part, not at the W-Cu/CuCr interface. Chromium in CuCr alloy part of the integrated material can improve Cr diffusing from the CuCr alloy to W-Cu composite and can be alloyed (near the W-Cu/CuCr interface) in the W-Cu composite. Thus the strength of W-Cu/CuCr interface is also increased.

  10. Distribution of heavy metals (Cu, Zn and Cr in groundwater from the area of a future radioactive waste repository Saligny – Romania

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    Tudorache A.

    2013-04-01

    Full Text Available A study of some heavy metals (Cu, Zn and Cr concentrations in natural groundwater has been conducted, by considering samples collected from the area located in the neighbourhood of Saligny village (Cernavodă, Romania. Atomic absorption spectrometry methods with thermal and electrothermal atomization has been developed, tested and used for some heavy metals content determination. The results show various concentrations of Cu, Zn and Cr in groundwater samples.

  11. Ni-Cr-B-Si+Cu-P-Sn复合钎料真空钎焊金刚石%Vacuum brazing diamond with Ni-Cr-B-Si+Cu-P-Sn composite filler metal

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    卢金斌; 贺亚勋; 张旺玺; 刘磊; 李华

    2016-01-01

    采用在镍基钎料中分别添加3%、5%和7%(质量分数)Cu-P-Sn组成新型复合钎料,并进行金刚石磨粒的钎焊实验,利用SEM、EDS和XRD对金刚石焊后的界面碳化物形貌及钎料组织进行测试分析。结果表明:添加5%Cu-P-Sn的复合钎料进行金刚石钎焊时,钎焊温度有所下降,金刚石表面碳化物较规整,并且数量有所下降,降低金刚石的热损伤。新型钎料中形成树枝晶α-Ni基固溶体和枝晶间Ni 31 Si 12、Cr 7 C 3等化合物的组织,不同含量Cu-P-Sn与Ni-Cr-B-Si合金可以较大程度互溶,可以实现钎料性能的调控,降低金刚石的热损伤。%A series of new composite brazing fillers metal were got by adding 3%, 5% or 7% (mass fraction) Cu-P-Sn in the primary brazing filler metal Ni-Cr-B-Si, respectively, then, they were used to braze diamond particles. The interface morphology of diamond carbide and the microstructure of brazing filler metal were tested by SEM, EDS and XRD. The results show that, when the composite brazing filler metal containing 5% Cu-P-Sn alloy, the carbide on the surface of the diamond is more regular and less with brazing temperature decreases, which decreases the thermal damage to the diamond. In the brazing filler alloy, the microstructures, such as dentrite included solid solution of Ni with some carbides like Ni31Si12 and Cr7C3, are formed. As the added component, Cu-P-Sn at different proportions can be dissolved into the primary brazing filler Ni-Cr-B-Si in large degree, which can adjust the properties of the filler and reduce the heat damage to the diamond.

  12. Cu-Cr Literature Review

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    Need, Ryan F. [Los Alamos National Laboratory

    2012-08-09

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

  13. Accumulation of heavy metals (Co, Cr, Cu, Mn, Zn in the freshwater alga Ulva type, sediments and water of the Wielkopolska region, Poland

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    Andrzej Rybak

    2013-12-01

    Full Text Available The concentration of five trace elements: cobalt (Co, chrome (Cr, copper (Cu, manganese (Mn and zinc (Zn was determined in the Ulva thalli, in the water and sediment collection from several inland sites (lakes, stream and river from the Wielkopolska region during summer 2010. The multielemental analysis of the heavy metal concentration was carried out with the use of ICP-OES method. The aim of this study was to determine the role of tubular forms as biomonitoring species. The relative abundance of metals in sediment decreased in the order: Mn > Zn > Cu > Cr > Co and in the water: Cr > Mn > Zn > Cu > Co. In Ulva thalli the distribution order from higher to lower was Mn > Zn > Cr > Cu > Co. The results indicate that the concentration changes of heavy metals in thallus, water and sediment have some differences, but concentration distribution tends to be similar, because among the analysed heavy metals Mn has the highest concentrations while Co the lowest abundance in the thalli and sediment of all the sites. Possibility to use freshwater species from Ulva genus as bioindicators of water pollution by manganese requires further study.

  14. Heavy Metals (Cd, Cu, Cr, Pb and Zn) in Meretrix meretrix Roding, Water and Sediments from Estuaries in Sabah, North Borneo

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    Abdullah, Mohd. Harun; Sidi, Jovita; Aris, Ahmad Zaharin

    2007-01-01

    Concentrations of heavy metals (Cd, Cu, Cr, Pb and Zn) in tissues of Meretrix meretrix Roding (M. meretrix R.), water and sediments from two estuaries were determined. One estuary is located in an urban area of Kota Kinabalu (Likas estuary) and the other in a rural district of Kota Belud (Kota Belud estuary), where both are in Sabah, North of…

  15. Fe(III) hydroxide nucleation and growth on quartz in the presence of Cu(II), Pb(II), and Cr(III): metal hydrolysis and adsorption.

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    Dai, Chong; Hu, Yandi

    2015-01-06

    Fe(III) hydroxide nanoparticles are an essential carrier for aqueous heavy metals. Particularly, iron hydroxide precipitation on mineral surfaces can immobilize aqueous heavy metals. Here, we used grazing-incidence small-angle X-ray scattering (GISAXS) to quantify nucleation and growth of iron hydroxide on quartz in 0.1 mM Fe(NO3)3 solution in the presence of Na(+), Cu(2+), Pb(2+), or Cr(3+) at pH = 3.7 ± 0.1. In 30 min, the average radii of gyration (R(g)) of particles on quartz grew from around 2 to 6 nm in the presence of Na(+) and Cu(2+). Interestingly, the particle sizes remained 3.3 ± 0.3 nm in the presence of Pb(2+), and few particles formed in the presence of Cr(3+). Quartz crystal microbalance dissipation (QCM-D) measurements showed that only Cr(3+) adsorbed onto quartz, while Cu(2+) and Pb(2+) did not. Cr(3+) adsorption changed the surface charge of quartz from negative to positive, thus inhibiting the precipitation of positively charged iron hydroxide on quartz. Masses and compositions of the precipitates were also quantified. This study provided new insights on interactions among quartz, iron hydroxide, and metal ions. Such information is helpful not only for environmental remediation but also for the doping design of iron oxide catalysts.

  16. Electronic structure and half-metallicity in new Heusler alloys CoYO2 (Y = Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn)

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    Esteki, S.; Ahmadian, F.

    2017-09-01

    First-principles calculations based on density functional theory (DFT) using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method were applied to study the electronic structures and magnetic properties of new Heusler alloys CoYO2 (Y = Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn). The calculated formation energies of these compounds were negative, therefore, they can be synthesized experimentally. All compounds were stable in ferromagnetic AlCu2Mn-type structure. In AlCu2Mn-type structure, CoScO2, CoFeO2, and CoNiO2 compounds were HM ferromagnets, CoCuO2 was a nearly half-metal, CoZnO2 was a spin gapless semiconductor, and other compounds were conventional ferromagnets. In CuHg2Ti-type structure, CoTiO2 compound had a nearly HM characteristic, CoVO2 was a spin gapless semiconductor, and other compounds were conventional ferromagnets. The origin of the half-metallic band gap for CoScO2 alloy Heusler alloy was well understood. The total magnetic moments of the three HM compounds obeyed Slater-Pauling rules (Mtot = 22-Ztot and Mtot = 32-Ztot). CoScO2 had the widest region of half-metallicity between the three half-metals indicating its high robustness of half-metallicity with respect to the variation of lattice constants.

  17. Microstructure and Shear Strength in Brazing Joint of Mo-Cu Composite with 304 Stainless Steel by Ni-Cr-P Filler Metal

    Science.gov (United States)

    Wang, Juan; Wang, Jiteng; Li, Yajiang; Zheng, Deshuang

    2015-07-01

    The brazing of Mo-Cu composite and 304 stainless steel was carried out in vacuum with Ni-Cr-P filler metal at 980 °C for 20 min. Microstructure in Mo-Cu/304 stainless steel joint was investigated by field-emission scanning electron microscope (FE-SEM) with energy dispersive spectrometer (EDS) and shear strength was measured by shearing test. The results indicate that shear strength of the Mo-Cu/304 stainless steel joint is about 155 MPa. There forms eutectic structure of γ-Ni solid solution with Ni3P in the braze seam. Ni-Cu(Mo) and Ni-Fe solid solution are at the interface beside Mo-Cu composite and 304 stainless steel, respectively. Shear fracture exhibits mixed ductile-brittle fracture feature with trans-granular fracture, ductile dimples and tearing edges. Fracture originates from the interface between brazing seam and Mo-Cu composite and it propagates to the braze seam due to the formation of brittle Ni5P2 and Cr3P precipitation.

  18. RESISTANCE OF MICROBIAL COMMUNITIES FROM ECUADOR ECOSYSTEMS TO REPRESENTATIVE TOXIC METALS - CrO4(2-), Co2+, Ni2+, Cu2+, Hg2+.

    Science.gov (United States)

    Tashyrev, O B; Prekrasna, Ie P; Tashyreva, G O; Bielikova, O Iu

    2015-01-01

    Microbial communities of the Ecuadorian Andes and volcano Tungurahua were shown to be super resistant to representative toxic metals. Maximum permissible concentrations of toxic metals were 100 ppm of Hg2+, 500 ppm of Co2+ and Ni2+, 1000 and 1500 ppm of Cr(VI), 10000 and 20000 ppm of Cu2+. The effect of metal concentration increasing on the biomass growth, CO2 and H2 synthesis was investigated. Two types of response of microbial communities on the increasing of toxic metals concentrations were discovered. The first type of response is the catastrophic inhibition of microbial growth. The second type of response is the absence of microbial growth inhibition at certain metal concentration gradient. The succession of qualitative structure of Ecuadorian microbial communities was shown for the first time. Bacteria, yeasts and finally fungi consistently dominate in the microbial community at the Cu2+ concentration raising. Microorganisms resistant to ultra-high concentrations of toxic metals (e.g., 3000 ... 20000 ppm of Cu2+) were isolated from Ecuadorian ecosystems. These microorganisms are able to accumulate toxic metals.

  19. Influence of selected heavy metals (As, Cd, Cr, Cu on nematode communities in experimental soil microcosm

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    Šalamún P.

    2015-12-01

    Full Text Available In this study, the effects of arsenic, cadmium, copper and chromium treatments were examined on a nematode community structure and proportion of functional groups in the microcosm for 30 days. The toxic effects on the nematode community did not correspond with metals mobility (EDTA extraction in soil as it was expected. The most toxic element with a significant degradation of community structure was chromium (low mobile, which negatively affected almost all observed ecological parameters (abundance, diversity and ecological indices. On the other hand, cadmium and arsenic influence was negligible even in the plots treated with the highest concentrations and the communities resembled to the control samples. Copper showed a stimulative effect on the community under low concentration (40 mg.kg-1, while under higher concentrations the stimulation was replaced by stress responses. The widely used ecological indices, such as the Maturity Index 2-5, Structure Index, and Shannon-Weaver Index and c-p groups showed the best bioindication potential among nematode parameters.

  20. Evaluation of the heavy metals Cr, Mn, Fe, Cu, Zn and Pb in water penny wort (Hydrocotyle ranunculoides) from the upper course of the Lerma River, Mexico; Evaluacion de los metales pesados Cr, Mn, Fe, Cu, Zn y Pb en sombrerillo de agua (Hydrocotyle ranunculoides) del curso alto del Rio Lerma, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Zarazua, G.; Avila P, P.; Tejeda, S. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Valdivia B, M.; Macedo M, G. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Zepeda G, C., E-mail: graciela.zarazua@inin.gob.mx [Universidad Autonoma del Estado de Mexico, Cerro de Coatepec s/n, Ciudad Universitaria, 50100 Toluca, Estado de Mexico (Mexico)

    2013-07-01

    The Lerma river is one of the most polluted water bodies in Mexico, it presents low biodiversity and lets grow up aquatic plants resistant to the pollution. The aim of this work was to evaluate the concentration and bioaccumulation factors of Cr, Mn, Fe, Cu, Zn and Pb in aerial and submerged structures of water penny wort (Hydrocotyle ranunculoides) from the upper course of the Lerma river. Inductively coupled plasma-optical emission spectrometry was used to determine the concentration of heavy metals in water and H. ranunculoides. Results show that the bioaccumulation factors of Fe and Zn were higher than those of Cu, Mn, Cr and Pb; with the exception of Zn, bioaccumulation factors were higher in the submerged structures of the plant, which shows low mobility of analyzed metals. As a result of this study H. ranunculoides can be considered as good indicator of metal pollution in water bodies. (Author)

  1. Assessment of heavy metal (Cu, Ni, Fe, Co, Mn, Cr, Zn) pollution in effluent dominated rivulet water and their effect on glycogen metabolism and histology of Mastacembelus armatus

    OpenAIRE

    Javed, Mehjbeen; Usmani, Nazura

    2013-01-01

    The present study was conducted to examine the contamination of rivulet situated at Kasimpur, Aligarh (27.218° N; 79.378° E). It receives the wastewater of Harduaganj Thermal Power Plant (HTPS) containing fly ash and heavy metals. Among the heavy metals estimated in the rivulet water, Fe (8.71 mgL-1) was present in the highest concentration followed by Cu (0.86 mgL-1), Zn (0.30 mgL-1) Mn (0.21 mgL-1), Ni (0.12 mgL-1), Co (0.11 mgL-1) and Cr (0.10 mgL-1). The values for the heavy metals such a...

  2. Phytoremediation efficiency of pondweed (Potamogeton crispus in removing heavy metals (Cu, Cr, Pb, As and Cd from water of Anzali wetland

    Directory of Open Access Journals (Sweden)

    Hajar Norouznia

    2014-09-01

    Full Text Available Plant-based remediation (i.e. phytoremediation is one of the most significant eco-sustainable techniques to cope with devastating consequences of pollutants. In the present study, the potential of a wetland macrophyt (i.e. Potamogeton crispus for the phytoremediation of heavy metals (i.e. Cu, Cr, Pb, As and Cd in the Anzali wetland was evaluated. The results showed that P. crispus tends to accumulate notable amounts of Cu, Cr, Pb, As and Cd according to their assayed concentrations as follows: 8.2 µg g-1 dw, 0.97 µg g-1 dw, 6.04 µg g-1 dw, 2.52 µg g-1 dw and 0.34 µg g-1 dw, respectively. Further accurate perception of the phytoremediation efficiency were conducted using both bioconcentration factor and translocation factor. The average of the highest bioconcentration factors was presented in a descending order as: 2.9×103, 1.9×103, 1.17×103, 0.68×103 and 0.46×103 for the Cu, Cr, Pb, Cd and As, respectively. Based on the results, P. crispus presents high potential to absorb all the alluded metals except for As and partly Cd. Correspondingly, the mean values of translocation factor were reported in the range of 0.41 to 2.24. Eventually, relying on the observed findings, the results support the idea that P. crispus species would be employed as the prospective candidate for the phytoremediation processes in Anzali wetland.

  3. An investigation of toxic heavy metals (Pb, Cd, Cu, Cr and Zn in Garlic (Allium sativum L. and soil samples collected from different locations of Punjab, Pakistan using atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Sadia Ata

    2014-07-01

    Full Text Available The present study is based on the determination of heavy metal contents (Pb, Cd, Cu, Cr and Zn in garlic and soil samples collected from ten different locations of Punjab, Pakistan using flame atomic absorption spectrometer. In garlic samples, Pb, Cd, Zn, Cu and Cr ranged from 4.9 to 94.6 mg/kg, 0.625 to 151.4 mg/kg, 3.7 to 56.4 mg/kg, 2.5 to 50.2mg/kg and 56.4 to 111.6 mg/kg respectively, whereas Pb, Cd, Cr, Zn and Cu in investigated soil samples ranged respectively from 57.4 to 99.6 mg/kg, 25.6 to 132.7 mg/kg, 61.7 to 115.1 mg/kg, 9.2 to 324.7 mg/kg and 15.5 to 34.5 mg/kg. Elevated concentration of Pb and Cd was found in garlic samples from Gujranwala, Cr concentration was found to be higher in samples collected from Raiwind while the other metals such as Cu and Zn were predominant in samples from Kasur. Heavy metal content in soil and garlic samples was within the permissible limits proposed by World Health Organization (WHO except Cd, Cr and Zn which showed elevated levels in almost all soil and garlic samples. Average concentrations determined in all samples represented that metal content in soil samples was in increasing order as Zn<Cu while in garlic samples, this order was as Cu. In the present study, it was observed that garlic samples from those areas presented relatively higher levels for investigated metals from where the soil samples also showed comparatively elevated levels of these metals.

  4. Environmental behaviors and potential ecological risks of heavy metals (Cd, Cr, Cu, Pb, and Zn) in multimedia in an oilfield in China.

    Science.gov (United States)

    Hu, Yan; Wang, Dazhou; Li, Yu

    2016-07-01

    The environmental behaviors of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in a Chinese oilfield were investigated using a steady-state multimedia aquivalence (SMA) model. The modeling results showed good agreement with the actual measured values, with average residual errors of 0.69, 0.83, 0.35, 0.16, and 0.54 logarithmic units for air, water, soil, sediment, and vegetation compartments, respectively. Model results indicated that most heavy metals were buried in sediment, and that transfers between adjacent compartments were mainly deposition from the water to the sediment compartment (48.59 %) and from the air to the soil compartment (47.74 %) via atmospheric dry/wet deposition. Sediment and soil were the dominant sinks, accounting for 68.80 and 25.26 % of all the heavy metals in the multimedia system, respectively. The potential ecological risks from the five heavy metals in the sediment and soil compartments were assessed by the potential ecological risk index (PERI). The assessment results demonstrate that the heavy metals presented low levels of ecological risk in the sediment compartment, and that Cd was the most significant contributor to the integrated potential ecological risk in the oilfield. The SMA model provided useful simulations of the transport and fate of heavy metals and is a useful tool for ecological risk assessment and contaminated site management.

  5. Apply Woods Model in the Predictions of Ambient Air Particles and Metallic Elements (Mn, Fe, Zn, Cr, and Cu at Industrial, Suburban/Coastal, and Residential Sampling Sites

    Directory of Open Access Journals (Sweden)

    Guor-Cheng Fang

    2012-01-01

    Full Text Available The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, and Cu in total suspended particulates (TSPs concentration, dry deposition at three characteristic sampling sites of central Taiwan. Additionally, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements were calculated with Woods models at these three characteristic sampling sites during years of 2009-2010. As for ambient air particles, the results indicated that the Woods model generated the most accurate dry deposition prediction results when particle size was 18 μm in this study. The results also indicated that the Woods model exhibited better dry deposition prediction performance when the particle size was greater than 10 μm for the ambient air metallic elements in this study. Finally, as for Quan-xing sampling site, the main sources were many industrial factories under process around these regions and were severely polluted areas. In addition, the highest average dry deposition for Mn, Fe, Zn, and Cu species occurred at Bei-shi sampling site, and the main sources were the nearby science park, fossil fuel combustion, and Taichung thermal power plant (TTPP. Additionally, as for He-mei sampling site, the main sources were subjected to traffic mobile emissions.

  6. Assessment of heavy metal (Cu, Ni, Fe, Co, Mn, Cr, Zn) pollution in effluent dominated rivulet water and their effect on glycogen metabolism and histology of Mastacembelus armatus.

    Science.gov (United States)

    Javed, Mehjbeen; Usmani, Nazura

    2013-01-01

    The present study was conducted to examine the contamination of rivulet situated at Kasimpur, Aligarh (27.218° N; 79.378° E). It receives the wastewater of Harduaganj Thermal Power Plant (HTPS) containing fly ash and heavy metals. Among the heavy metals estimated in the rivulet water, Fe (8.71 mgL(-1)) was present in the highest concentration followed by Cu (0.86 mgL(-1)), Zn (0.30 mgL(-1)) Mn (0.21 mgL(-1)), Ni (0.12 mgL(-1)), Co (0.11 mgL(-1)) and Cr (0.10 mgL(-1)). The values for the heavy metals such as Fe, Ni and Mn were beyond the limits set by UNEPGEMS. Bioaccumulation of these heavy metals was detected in tissues such as gills, liver, kidney, muscle and integument of the fish Mastacembelus armatus. Accumulation of Fe (213.29 - 2601.49 mgkg(-1).dw) was highest in all the organs. Liver was the most influenced organ and integument had the least metal load. The accumulation of Fe, Zn, Cu and Mn, observed in the tissues were above the values recommended by FAO/WHO. Biochemical estimation related to blood glucose, liver and muscle glycogen conducted showed significant (p < 0.01) elevation in blood glucose content over control (17.73%), whereas liver glycogen dropped significantly (p < 0.01) over control (-89.83%), and similarly muscle glycogen also decreased significantly (p < 0.05) over control (-71.95%), suggesting enhanced glycolytic capacity to fuel hepatic metabolism. Histopathological alterations were also observed in selected organs (gills, liver and kidney) of Mastacembelus armatus.

  7. Investigation of heavy metal (Cu, Pb, Cd, and Cr) stabilization in river sediment by nano-zero-valent iron/activated carbon composite.

    Science.gov (United States)

    Chen, Wei-fang; Zhang, Jinghui; Zhang, Xiaomao; Wang, Weiya; Li, Yuxiang

    2016-01-01

    Nano-zero-valent iron/activated carbon (nZVI/AC) composite was evaluated for its effectiveness in the stabilization of Cu, Pb, Cd, and Cr in dredged river sediment. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) were adopted to compare the effects of nZVI/AC dosage, particle size, time duration, and temperature on heavy metal leachability. The results show that leachability dropped considerably with the addition of nZVI/AC and powdered particles in the size of 0.075-0.18 mm was more effective in stabilization than granular ones. Stabilization effect was stable in long-term and robust against changes in temperature. Tessier sequential extraction revealed that heavy metals were associated with solid particle, inorganic or organic matters in sediment. The addition of nZVI/AC was able to convert relatively weakly bound heavy metals into more strongly bound species and thus reduce the bioavailability and toxicity. Also, the standard potential of heavy metals may decide the mechanism of stabilization process.

  8. Assessment of heavy metals/metalloid (As, Pb, Cd, Ni, Zn, Cr, Cu, Mn) concentrations in edible fish species tissue in the Pearl River Delta (PRD), China.

    Science.gov (United States)

    Leung, H M; Leung, A O W; Wang, H S; Ma, K K; Liang, Y; Ho, K C; Cheung, K C; Tohidi, F; Yung, K K L

    2014-01-15

    The major aim of this study was to investigate heavy metal content of edible fish in the PRD. Eleven species of fish (consisting of 711 individuals) [catfish (Clarias fuscus), tilapia (Oreochromis mossambicus), grass carp (Ctenopharyngodon idellus), bighead carp (Aristichthys nobilis), mandarin fish (Siniperca kneri), snakehead (Channa asiatiea), black bass (Micropterus salmoides), mangrove snapper (Lutjanus griseus), star snapper (Lutjanu stellatus), snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides)] were collected for the analyses of heavy metals. Overall concentrations (mg/kg, ww) in the fish muscles were: As (0.03-1.53), Pb (0.03-8.62), Cd (0.02-0.06), Ni (0.44-9.75), Zn (15.7-29.5), Cr (0.22-0.65), Cu (0.79-2.26), Mn (0.82-6.91). Significant level of Pb were found in tilapia at all locations. It is recommended that heavy metal concentrations in different fish species must be determined on a regular basis in the future so as to reduce human health risks from acute and chronic food intoxication.

  9. Adsorption of some transition metal ions (Cu(II), Fe(III), Cr(III) and Au(III)) onto lignite-based activated carbons modified by oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Paunka St. Vassileva; Albena K. Detcheva [Bulgarian Academy of Sciences, Sofia (Bulgaria). Institute of General and Inorganic Chemistry

    2010-03-15

    The main purpose of the present work was to study the adsorption of some transition metal ions from aqueous solution via a novel porous material obtained from Bulgarian lignite (Chukurovo deposit) and its oxidized modifications. The adsorption of Cu(II), Fe(III), Cr(III) and Au(III) ions was investigated using batch methods to study solutions with different concentrations and acidities. It was found that the adsorption process was affected significantly by the pH value of the aqueous solution. Treatment of the equilibrium data using the linear Langmuir, Freundlich and Dubinin-Radushkevich models allowed the maximum adsorption capacities to be calculated. The uptake of Au(III) ions was almost 100% for the three adsorbents investigated, being greater than 300 mg/l and independent of the pH over the pH range studied. The initial activated carbon proved to be the most suitable for the selective adsorption of Au(III) ions from aqueous solutions in the presence of other transition metal ions, while its oxidized modification Ch-P exhibited an enhanced adsorption efficiency towards transition metals.

  10. Adsorption of Some Transition Metal Ions (Cu(II), Fe(III), Cr(III) and Au(III)) onto lignite-based activated carbons modified by oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Vassileva, P.S.; Detcheva, A.K. [Bulgarian Academy of Science, Sofia (Bulgaria)

    2010-07-01

    The main purpose of the present work was to study the adsorption of some transition metal ions from aqueous solution via a novel porous material obtained from Bulgarian lignite (Chukurovo deposit) and its oxidized modifications. The adsorption of Cu(II), Fe(III), Cr(III) and Au(III) ions was investigated using batch methods to study solutions with different concentrations and acidities. It was found that the adsorption process was affected significantly by the pH value of the aqueous solution. Treatment of the equilibrium data using the linear Langmuir, Freundlich and Dubinin-Radushkevich models allowed the maximum adsorption capacities to be calculated. The uptake of Au(III) ions was almost 100% for the three adsorbents investigated, being greater than 300 mg/l and independent of the pH over the pH range studied. The initial activated carbon proved to be the most suitable for the selective adsorption of Au(III) ions from aqueous solutions in the presence of other transition metal ions, while its oxidized modification Ch-P exhibited an enhanced adsorption efficiency towards transition metals.

  11. Structural and microstructural comparative analysis on metallic alloys of composition Cu{sub y%}-Ni{sub x%}-Me (Me = Sn, Cr, Al, Pt)

    Energy Technology Data Exchange (ETDEWEB)

    Marques, I.M.; Okazaki, A.K.; Silveira, C.R. da; Carvalhal, M.A.; Monteiro, W.A.; Carrio, J.A.G. [Physics Department, CCH, Presbyterian Mackenzie University, Materials Science and Technology Centre, Sao Paulo, SP (Brazil); Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: jgcarrio@mackenzie.br

    2010-07-01

    This work presents a comparative study of microstructural and electrical properties of polycrystalline material Cu-Ni alloys synthesized by conventional and powder metallurgy. A sample of Cu{sub 99,33%} Ni{sub 0,23%} Pt{sub 0,43%} was produced in electric furnace with voltaic arc and various samples containing Al, Sn and Cr as third element were produced by powder metallurgy. The microstructure of the samples was studied by optical microscopy, Vickers micro hardness and x rays powder diffraction. Their electrical conductivity was measured with a milliohmeter Agilent (HP) 4338B. Refinements of the crystalline structure of the samples were performed by the Rietveld method, using the refinement program GSAS. The refinement results and Fourier differences calculations indicate that the copper matrix structure presents not significant distortions by the used amounts of the other metal atoms. The refinement of non structural parameters allowed the micro-structural characterization. The dependence of the micro-structure with thermal and mechanical treatments is studied. (author)

  12. Explosive compaction of CuCr alloys

    Institute of Scientific and Technical Information of China (English)

    李金平; 罗守靖; 龚朝晖; 牛玮; 纪松

    2002-01-01

    The production of CuCr alloys utilizing explosive compaction was studied. Mixture powders of CuCr alloys placed in tubes with a dimension of d14.0mm×21.4mm can be compacted using explosive pads of 16.5mm or 22.5mm. Thicker pads of explosive make the compacts more porous. The effects of the ratio of me/mp, ratio of me/(mp+mt) and impact energy on the density of compacts were similar, they were chosen to control explosive compaction, respectively. When adequate value of the parameters me/mp, me/(mt+mp) and impact energy of unit area of tube was chosen, high density(7.858g/cm3), high hardness(HB189) and low conductance (13.6MS/m) of CuCr alloys could be made by explosive compaction. The general properties of CuCr alloys by explosive compaction are similar to those of CuCr alloys by traditional process.

  13. Growth and electronic structure of Cu on Cr sub 2 O sub 3 (0001)

    CERN Document Server

    Xiao Wen De; Guo Qi; Wang, E G

    2003-01-01

    The deposition of Cu at room temperature on a Cr sub 2 O sub 3 (0001) substrate is studied by x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and low-energy-electron diffraction. The results indicate that at RT Cu is highly dispersed on the substrate at initial deposition. X-ray induced Auger spectra, Auger parameter and ultraviolet photoelectron spectroscopy show that at the initial coverage the deposited Cu is in the Cu(I) state due to the interaction of Cu with the Cr sub 2 O sub 3 substrate; Cu becomes metallic at Cu coverages of > 4 monolayer equivalent. The formation of Cu two-dimensional or quasi-2D patches is followed by the formation of Cu three-dimensional clusters. Cu grows epitaxially on the Cr sub 2 O sub 3 (0001) films as Cu(111)R 30 deg. as observed by low-energy-electron diffraction.

  14. Trace element geochemistry of CR chondrite metal

    CERN Document Server

    Jacquet, Emmanuel; Alard, Olivier; Kearsley, Anton T; Gounelle, Matthieu

    2015-01-01

    We report trace element analyses by laser ablation inductively coupled plasma mass spectrometry of metal grains from 9 different CR chondrites, distinguishing grains from chondrule interior ("interior grains"), chondrule surficial shells ("margin grains") and the matrix ("isolated grains"). Save for a few anomalous grains, Ni-normalized trace element patterns are similar for all three petrographical settings, with largely unfractionated refractory siderophile elements and depleted volatile Au, Cu, Ag, S. All types of grains are interpreted to derive from a common precursor approximated by the least melted, fine-grained objects in CR chondrites. This also excludes recondensation of metal vapor as the origin of the bulk of margin grains. The metal precursors presumably formed by incomplete condensation, with evidence for high-temperature isolation of refractory platinum-group-element (PGE)-rich condensates before mixing with lower temperature PGE-depleted condensates. The rounded shape of the Ni-rich, interior ...

  15. Evaluation of the Accumulation of Trace Metals (as, U, CR, CU, PB, Zn) on Iron-Manganese Coatings on in Situ Stream Pebbles and Emplaced Substrates

    Science.gov (United States)

    Turpin, M. M.; Blake, J.; Crossey, L. J.; Ali, A.; Hansson, L.

    2015-12-01

    Exposure to trace metals (As, U, Cr, Cu, Pb, Zn) has potential negative health effects on human populations and wildlife. Geothermal waters often have elevated concentrations of trace elements and understanding the geochemical cycling of these elements can be challenging. Previous studies have utilized in situ stream pebbles and glass or ceramic substrates with iron-manganese oxide coatings to understand contamination and or chemical cycling. This project's main focus is to develop an ideal tracing method using adsorption onto substrate surfaces and to define key parameters that are necessary for the phenomenon of adsorption between trace metals and these surface coatings to occur. Sampling locations include the Jemez River and Rio San Antonio in the Jemez mountains, northern New Mexico. Both streams have significant geothermal inputs. Pebbles and cobbles were gathered from the active stream channel and 6mm glass beads and 2 X1 in. ceramic plates were placed in streams for three weeks to allow for coating accumulation. Factors such as leachate type, water pH, substrate type, coating accumulation period and leach time were all considered in this experiment. It was found that of the three leachates (aqua regia, 10% aqua regia and hydroxylamine), hydroxylamine was the most effective at leaching coatings without dissolving substrates. Samples leached with aqua regia and 10% aqua regia were found to lose weight and mass over the following 5, 7, and 10 day measurements. Glass beads were determined to be more effective than in stream pebbles as an accumulation substrate: coatings were more easily controlled and monitored. Samples leached with hydroxylamine for 5 hours and 72 hours showed little difference in their leachate concentrations, suggesting that leach time has little impact on the concentration of leachate samples. This research aims to find the best method for trace metal accumulation in streams to aid in understanding geochemical cycling.

  16. Effects of Cu(II on the Adsorption Behaviors of Cr(III and Cr(VI onto Kaolin

    Directory of Open Access Journals (Sweden)

    Juanjuan Liu

    2016-01-01

    Full Text Available The adsorption of Cr(III or Cr(VI in the absence and presence of Cu(II onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential (ζ, especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II, qmixCr(III reached the maximum adsorption capacity of 0.73 mg·g−1 at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI and Cu(II system (qmixCr(VI was observed at pH 2.0 (0.38 mg·g−1. Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III instead of Cr3+ ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II through surface complexation, leading to Cu(II inhibited Cr(VI adsorption. Moreover, Cr(III and Cr(VI removal efficiency had a positive correlation with distribution coefficient Kd. Cr(III and Cr(VI removal efficiency had a positive correlation with distribution coefficient Kd and that of adsorption affinities of Cr(III or Cr(VI on kaolin was found to be Kd Cr(III Kd Cr(VI-Cu(II.

  17. A study on the use of nano/micro structured goethite and hematite as adsorbents for the removal of Cr(III, Co(II, Cu(II, Ni(II, and Zn(II metal ions from aqueous solutions.

    Directory of Open Access Journals (Sweden)

    Hala Hafez

    2012-06-01

    Full Text Available Numerous adsorbents for the removal of heavy metals from aqueous solutions are in various stages of research. The main goal for most of this research is to develop low-cost and environmentally friendly materials for the removal of heavy metals from contaminated groundwater, surface water, and drinking water. Materials that have ion exchange sites are expected to be able to efficiently remove heavy metals from water. Iron oxides, especially in the micro/nano structured forms, are good candidates for the removal of toxic heavymetal ions from water due to their structural properties. In the present work the efficiency of synthesized micro/nano particles of goethite and hematite for the removal of Cr(III, Co(II , Cu(II, Ni(II and Zn(II ions from water was compared. The absorbent capability of goethite as a function of pH, contact time, and initialmetal ion concentration was studied. The results showed that maximum absorption for all metal ions using goethite occurred at a pH=5.3, which was a common trend for all metal ions. At this pH and after one hour contact time goethite was able to adsorb about 100% of the Cu ions (50mg/g, 85% (42.5 mg/g of the Ni ions, 70% (35mg/g of the Cr and Co ions and 60% (30 mg/g of Zn ions from the solutions. Whereas and under the same conditions hematite was able to adsorb 20% (10mg/g of the Cu ions, 85% (42.5mg/g of the Ni ions, 95% (47.5mg/g of the Cr ions, 80% (40mg/g of the Zn ions, and 70% (35mg/g of the Co ions. Both oxides are equally efficient for the removal of Co(II and Ni(II from water. However, goethite is a much more efficient candidate than hematite for the removal of Cu(II,while hematite is more efficient adsorbent for Zn(II and Cr(III. The adsorption affinity of the five metallic cations to goethite is Cu > Ni > Co ~ Cr > Zn, whereas the adsorption affinity of the cations to hematite is Cr > Ni > Zn > Co > Cu. Under the conditions used in the batch experiments (mass of goethite 2g/l maximumadsorption of

  18. The influence of metal speciation in combustion waste on the efficiency of Cu, Pb, Zn, Cd, Ni and Cr bioleaching in a mixed culture of sulfur-oxidizing and biosurfactant-producing bacteria.

    Science.gov (United States)

    Karwowska, Ewa; Wojtkowska, Małgorzata; Andrzejewska, Dorota

    2015-12-15

    Metal leachability from ash and combustion slag is related to the physico-chemical properties, including their speciation in the waste. Metals speciation is an important factor that influences the efficiency of metal bioleaching from combustion wastes in a mixed culture of acidophilic and biosurfactant-producing bacteria. It was observed that individual metals tended to occur in different fractions, which reflects their susceptibility to bioleaching. Cr and Ni were readily removed from wastes when present with a high fraction bound to carbonates. Cd and Pb where not effectively bioleached when present in high amounts in a fraction bound to organic matter. The best bioleaching results were obtained for power plant slag, which had a high metal content in the exchangeable, bound to carbonates and bound to Fe and Mg oxides fractions- the metal recovery percentage for Zn, Cu and Ni from this waste exceeded 90%.

  19. Evaluation of the air quality regarding total suspended particles and heavy metals (Pb, Cd, Ni, Cu, Cr) in the Hermosillo city, Sonora, Mexico, during a yearly period; Evaluacion de la calidad del aire respecto de particulas suspendidas totales y metales pesados (Pb, Cd, Ni, Cu, Cr) en la Ciudad de Hermosillo, Sonora, Mexico, durante un periodo anual

    Energy Technology Data Exchange (ETDEWEB)

    Cruz C, M. E.; Quintero N, M. [Universidad Autonoma de Baja California, Instituto de Ingenieria, Campus Mexicali, Calle de la Normal s/n, y Blvd. Benito Juarez, Col. Insurgentes Este, Mexicali, Baja California (Mexico); Gomez A, A.; Varela S, J., E-mail: martincruzcampas@hotmail.com [Universidad de Sonora, Departamento de Ingenieria Quimica y Metalurgia, Blvd. Rosales y Luis Ensina s/n, Edificio 5B, Col. Centro, 83000 Hermosillo, Sonora (Mexico)

    2013-07-01

    In the present study, the air quality of the city of Hermosillo, Sonora, Mexico was assessed considering total suspended particulates (tsp) and heavy metals (Pb, Cd, Ni, Cu, Cr) from June 2001 through May 2002 in three monitoring sites Centro (Mazon), Nor este (CESUES) and Noroeste (CBTIS). The filter-samples used for that purpose were provided by the Air Quality Evaluation and Improvement Program (PEMCA) of the municipality of Hermosillo. The sampling method was based on high volume sampling frequency set every 6 days with non-simultaneous sampling among the three sampling sites. Filters were dissolved for metal determination by acidic-extraction, and then analyzed by flame atomic absorption spectrophotometry. Results indicate that tsp concentrations at Centro and Noroeste sites were frequently higher than the maximum daily permissible level (260 {mu}g/m{sup 3}), while in the three sites the annual average was higher than the maximum annual permissible level (75 {mu}g/m{sup 3}) both established in the standard NOM-024-Ssa-1993 (Ssa 1994a). According to the Air Quality Standard Index (US EPA 1992a), used in Mexico by Air Quality Metropolitan Index (IMECA) the results indicate that the air quality in the city of Hermosillo regarding tsp was placed between no satisfactory and poor. In regard to heavy metals (Pb, Cd, Ni, Cu, Cr), concentrations detected were below the maximum permissible levels and/or criteria taking into account the standard NOM-026-Ssa-1993 (Ssa 1994b), the Who criterion (2000), the European Union criterion (Cec 2003), and the European Environmental Agency criteria (EEA 2004). Such findings would mean that airborne metals are of no concern; however, air quality is still classified as no satisfactory due to high particulate matter concentrations. Keeping air quality parameters monitoring is recommended in order to get extensive data for use in risk studies of air quality and health (morbidity/mortality), as well as topographic conditions

  20. Magnetic properties of CuCr2Se4 and CuCr1.5Ti0.5Se4

    Science.gov (United States)

    Behera, P. Suchismita; Bhobe, P. A.; Nigam, A. K.

    2016-05-01

    CuCr2Se4 is a potentially attractive versatile material, from the point of view of spintronics application. It shows characteristics of a ferromagnetic conductor at room temperature and with suitable doping it is proposed to show half-metallicity. With an aim to understand the effect of doping at Cr-site by a non-magnetic ion, we carried out investigation of magnetic and crystal structure properties of polycrystalline CuCr2Se4 and CuCr1.5Ti0.5Se4 spinel. These materials were prepared by solid state synthesis and characterized using room temperature powder XRD and measurement of magnetic properties. The XRD patterns were analyzed using Rietveld technique and lattice constants were estimated. Formation of a small amount of Cr3Se4 phase was identified from the XRD profiles. However, the magnetic properties do not seem to be affected much by it. Compared to parent compound, CuCr2Se4, the ferromagnetic Curie temperature TC in CuCr1.5Ti0.5Se4 was found to decrease to 208 K. But its magnetic moment (μB/f.u.) determined from the saturation magnetization value measured at 5 K, differed only slightly from that of CuCr2Se4. Our preliminary results are presented here.

  1. An anti CuO2-type metal hydride square net structure in Ln2M2As2H(x) (Ln=La or Sm, M=Ti, V, Cr, or Mn).

    Science.gov (United States)

    Mizoguchi, Hiroshi; Park, SangWon; Hiraka, Haruhiro; Ikeda, Kazutaka; Otomo, Toshiya; Hosono, Hideo

    2015-03-02

    Using a high pressure technique and the strong donating nature of H(-), a new series of tetragonal La2Fe2Se2O3-type layered mixed-anion arsenides, Ln2M2As2H(x), was synthesized (Ln=La or Sm, M=Ti, V, Cr, or Mn; x≈3). In these compounds, an unusual M2H square net, which has anti CuO2 square net structures accompanying two As(3-) ions, is sandwiched by (LaH)2 fluorite layers. Notably, strong metal-metal bonding with a distance of 2.80 Å was confirmed in La2Ti2As2H2.3, which has metallic properties. In fact, these compounds are situated near the boundary between salt-like ionic hydrides and transition-metal hydrides with metallic characters.

  2. Microstructure of directionally solidified Cu-Cr composites

    Institute of Scientific and Technical Information of China (English)

    毕晓勤; 李金山; 胡锐; 耿兴国; 朱琦; 傅恒志

    2004-01-01

    Cu-Cr composites were prepared by self-made directional solidification equipment with the high temperature gradient and double-zone heating. The microstructural evolution was investigated during the directional solidification with the different solidification rate for Cu-1.0%Cr, Cu-1.7%Cr and Cu-5.6%Cr alloys, respectively. It is shown that for the hypoeutectic Cu-1.0%Cr alloy, the general microstructures consist of primary α(Cu) phase and the rod-like or needle-like (α+β) eutectics, and for the hypereutectic Cu-1. 7%Cr and Cu-5.6%Cr alloys, α(Cu)phase, primary β(Cr) phase and (α+β) eutectics coexist. With the increase of the solidification rate, the morphology evolution of every phase is that, 1st cellular(dendrite) of α(Cu) phase thins and cellular(dendrite) spacing shortens gradually, (α+β) eutectics set in α(Cu) cellular or dendrite, and primary β(Cr) phase distributes unevenly on α (Cu) matrix, whose morphology undergoes the change from dendrite to particle.

  3. Study on the behavior of the heavy metals Cu, Cr, Ni, Zn, Fe, Mn and {sup 137}Cs in an estuarine ecosystem using Mytilus galloprovincialis as a bioindicator species: the case of Thermaikos gulf, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Catsiki, Vassiliki-Angelique [Hellenic Centre for Marine Research, Mavro Lithari, 46.7 Km Athens-Sounio, Anavyssos Attikis 19013 (Greece)]. E-mail: cats@ath.hcmr.gr; Florou, H. [National Centre for Scientific Research ' Demokritos' , Ag. Paraskevi 153 10, Athens (Greece)

    2006-07-01

    Mussels are worldwide recognized as pollution bioindicators and used in Mussel Watch programs, because they accumulate pollutants in their tissues at elevated levels in relation to pollutant biological availability in the marine environment. The present study deals with the use of Mytilus galloprovincialis as a local bioindicator of heavy metal and {sup 137}Cs contamination in an estuarine ecosystem (Thermaikos gulf, Greece in Eastern Mediterranean). M. galloprovincialis samples were collected monthly from two aquaculture farms during the period April to October 2000. Analyses for the heavy metals Cu, Cr, Ni, Zn, Fe, Mn and {sup 137}Cs showed that the concentrations measured were low and similar to those from other non-polluted Mediterranean areas. In terms of the two sampling stations, there were no statistically significant differences between them. On the contrary, the seasonal evolution of either heavy metals or {sup 137}Cs levels presented high variation. The levels were found to increase during the cold period of the year, especially for Cu, Zn, Mn and Cr which are essential for life. Stable metals were positively inter-related and moreover, metals more involved in biochemical activities seem to present more correlations than others with less significant role in the metabolism of the organisms.

  4. Synthesis and characterization of Cu-Cr-O nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LI Wei; CHENG Hua

    2007-01-01

    Cu-Cr-O nanocomposites that can be used as additives for the catalytic combustion of AP(ammonium perchlorate)-based solid-state propellants were synthesized via a citric acid(CA) complexing approach. Techniques of TG-DTA, XRD as well as TEM were employed to characterize the thermal decomposition procedure, crystal phase, micro-structural morphologies and grain size of the as-synthesized materials respectively. The results show that well-crystallized Cu-Cr-O nanocomposites can be produced after the CA-Cu-Cr precursors are calcined at 500 ℃ for 3 h. Phase composition of the as-obtained Cu-Cr-O nanocomposites depends on the molar ratio of Cu to Cr in the starting reactants. Addition of the as-synthesized Cu-Cr-O nanocomposites as catalysts enhances the burning rate as well as lowers the pressure exponent of the AP-based solid-state propellants considerably. Noticeably, catalyst with a Cu/Cr molar ratio of 0.7 exhibits promising catalytic activity with high burning rate and low pressure exponent at all pressures, due to the effective phase interaction between the spinel CuCr2O4 and delafossite CuCrO2 contained in the as-synthesized Cu-Cr-O nanocomposites.

  5. Core-shell heterostructures of SnM (M = (Fe, Ni, and Cr) or Cu) alloy nanowires @ CNTs on metallic substrates

    Science.gov (United States)

    Zhong, Yu; Zhang, Yong; Cai, Mei; Balogh, Michael P.; Li, Ruying; Sun, Xueliang

    2013-04-01

    Sn alloy nanowires encapsulated in carbon nanotubes (SnM (M = (Fe, Ni, and Cr) or Cu) @ CNTs) were prepared in situ by a chemical vapor deposition (CVD) method, in which Sn came from a vaporized precursor while the alloy elements were supplied by the substrate. The heterostructures were grown on two types of substrates including stainless steel with high catalytic effectiveness and Cu substrates with low catalytic effectiveness for generating graphite layers, respectively. Pure Sn powder and C2H4 were employed to provide Sn and carbon precursors. The products were investigated by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) mapping. The morphology, structure and composition of the nanomaterials depended significantly on the surface conditions of the substrates. While SnCu alloy nanowires encapsulated in carbon nanotubes were grown on the Cu substrate, carbon nanotubes filled with alloy nanowires and porous carbon fibers decorated internally with alloy particles were observed on the stainless steel substrate. The growth mechanisms of the heterostructures were proposed.

  6. 复合污染下Cu、Cr、Ni和Cd在水稻植株中的富集特征%Enrichment of Heavy Metals in Rice under Combined Pollution of Cu, Cr, Ni and Cd

    Institute of Scientific and Technical Information of China (English)

    林华; 张学洪; 梁延鹏; 刘杰; 黄海涛

    2014-01-01

    掌握水稻对污染土壤中重金属的吸收和富集特征,为科学认识水稻中重金属的残留问题、健康风险提供理论依据。采用田间试验,研究了4个不同处理量Cu、Cr、Ni、Cd复合污染下水稻的富集特征及其随生育期的变化规律。结果表明,重金属在水稻植株各部位中吸收富集系数的大小依次为:Cd>Cu>Ni>Cr,根部重金属吸收富集系数是地上各部位的吸收富集系数的2~100倍。各重金属在水稻植株不同部位的积累分布明显不同,成熟期水稻植株中Cu在水稻不同部位的质量分数为根>茎≥叶>米粒>谷壳,Ni的分布规律为根>叶>茎>米粒>谷壳,Cr的分布规律为根>叶>谷壳≥茎>米粒,Cd的分布规律为根>茎>叶>米粒>谷壳;且随着重金属处理量的增加,水稻植株不同部位的重金属质量分数也呈上升趋势。成熟期米粒中Cu、Ni、Cr和Cd的质量分数范围分别为:4.50~6.19、1.86~4.63、0.72~0.76和0.08~0.39 mg·kg-1,与无公害食品标准(GB15199-94、GBT2762-2005)相比,米粒中Cu和Cr的质量分数均未超标,而Ni和Cd(Cd高剂量处理时)的质量分数均超标,存在食用安全风险。重金属在水稻植株不同部位的质量分数随生育期均呈现先升后降的趋势,灌浆中期达到最大,而到成熟期又明显降低。不同重金属在水稻植株中的富集能力和分布规律均呈现明显差异,不同生育期水稻植株中重金属的质量分数明显不同但其质量分数变化呈明显规律性。%Absorption and Accumulation Characteristics of heavy metals by rice in the heavy-metal polluted soils were analyzed to provide theoretical basis for recognizing heavy metals residue in rice, health risk. The enrichment characteristics and changes of Cu, Cr, Ni and Cd integrated effects in rice during their growing were studied through field experiment. The results showed that the enrichment sequence of four heavy metals

  7. EVALUACIÓN DE LA CALIDAD DEL AIRE RESPECTO DE PARTÍCULAS SUSPENDIDAS TOTALES (PST) Y METALES PESADOS (Pb, Cd, Ni, Cu, Cr) EN LA CIUDAD DE HERMOSILLO, SONORA, MÉXICO, DURANTE UN PERIODO ANUAL

    OpenAIRE

    Martín Eusebio CRUZ CAMPAS; Agustín GÓMEZ ÁLVAREZ; Margarito QUINTERO NÚÑEZ; Jaime VARELA SALAZAR

    2013-01-01

    En el presente estudio se evaluó la calidad del aire para la ciudad de Hermosillo, Sonora, México, respecto de partículas suspendidas totales (PST) y metales pesados (Pb, Cd, Ni, Cu, Cr) durante el período junio de 2001 a mayo de 2002, en los sitios de monitoreo Centro (Mazón), Noreste (CESUES) y Noroeste (CBTIS). Los filtros muestra usados para ese propósito fueron proporcionados por el Programa de Evaluación y Mejoramiento de la Calidad del Aire (PEMCA) del Ayuntamiento de Hermosillo. El mu...

  8. CMT法30CrMnSi钢板表面熔敷CuSi3接头组织结构特征%Microstructure characteristics of CuSi3 cladding on 30CrMnSi steel with cold metal transfer technology

    Institute of Scientific and Technical Information of China (English)

    姜晓飞; 何鹏; 冯吉才; 石常亮

    2007-01-01

    利用CMT(cold metal transfer)技术在30CrMnSi钢板表面熔敷CuSi3;采用背散射、能谱分析及X射线衍射等方法对接头区显微组织及成分进行了研究.结果表明,CMT技术实现了熔敷层与基体的冶金结合,送丝速度为5.0 m/min,焊接速度为17.0 mm/s时,稀释率极低;界面区由Fe3Si化合物、α-Fe及ε-Cu组成.送丝速度较低时,界面结构为Fe3Si/α-Fe+ε-Cu/α-Fe,熔敷区出现Fe2Si化合物;提高送丝速度,界面结构为Fe3Si+α-Fe+ε-Cu/α-Fe+ε-Cu,Fe2Si化合物被Fe3Si化合物取代;进一步提高送丝速度,界面结构为α-Fe+ε-Cu,弥散分布的球状富铁相聚合成长为星状及大块团状的α-Fe固溶体.送丝速度的变化对熔敷区组织具有显著影响.

  9. Effect of temperature on mechanical alloying of Cu-Zn and Cu-Cr system

    Institute of Scientific and Technical Information of China (English)

    ZUO Ke-sheng; XI Sheng-qi; ZHOU Jin-gen

    2009-01-01

    Cu-Zn and Cu-Cr powders were milled with an attritor mill at room temperature, -10, -20 and -30 ℃, respectively. Phase transformation and morphology evolution of the alloyed powder were investigated by X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM). The results show that lowering temperature can delay mechanical alloying(MA) process of Cu-Zn system with negative mixing enthalpy, and promote MA process of Cu-Cr system with positive mixing enthalpy. As for Cu-Cr and Cu-Zn powders milled at -10 ℃, lamellar structures are firstly formed, while fewer lamellar particles can be found when the powder is milled at -20 ℃. When the alloyed powder is annealed at 1 000 ℃, Cu(Cr) solid solution is decomposed and Cr precipitates from Cu matrix, whereas Cu(Zn) solid solution keeps stable.

  10. Cu-Cr-O Functionalized ETS-2 Nanoparticles for Hot Gas Desulfurization.

    Science.gov (United States)

    Yazdanbakhsh, Farzad; Alizadehgiashi, Molen; Bläsing, Marc; Müller, Michael; Sawada, James A; Kuznicki, Steven M

    2016-01-01

    Engelhard Titanium Silicate-2 (ETS-2), a sodium nanotitanate, was surface functionalized by ion exchanging the solid with copper and chromium ions. The ability of this bi-metallic adsorbent to remove H2S at elevated temperatures was assessed using a dynamic breakthrough system and contrasted against an analogous mixed metal oxide, Cu-Cr-O. Unlike Cu-Cr-O, the H2S capacity for Cu-Cr-ETS-2 remains unchanged from 350 °C up to 950 °C. Using ETS-2 as a support for the metals increased the adsorbents surface area and improved its sulfur capacity from 35 mg H₂S/g for Cu-Cr-O to 61 mg H₂S/g adsorbent for CuCr-ETS-2. The consistent presence of Cu₉S₅ on the sulfided adsorbents suggests that chromium effectively stabilizes the copper against reduction to metallic copper up to temperatures as high as 950 °C.

  11. Mechanical properties and electrical conductivity of Cu-Cr and Cu-Cr-4% SiC nanocomposites for thermo-electric applications

    Energy Technology Data Exchange (ETDEWEB)

    Mula, Suhrit, E-mail: suhritmula@gmail.com [Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695 (United States); Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela 769008, Orissa (India); Sahani, Pankajini [Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela 769008, Orissa (India); Pratihar, S.K. [Department of Ceramic Engineering, National Institute of Technology, Rourkela 769008, Orissa (India); Mal, Siddhartha; Koch, Carl C. [Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695 (United States)

    2011-05-25

    Highlights: {yields} Ball-milled Cu-Cr and Cu-Cr-SiC nanopowders successfully consolidated by microwave sintering. {yields} Addition of nanosize SiC in Cu-Cr leads to enhanced sintered density, wear and hardness. {yields} A good combination of wear resistance, hardness and electrical conductivity resulted in Cu{sub 94}Cr{sub 6}-4% SiC. {yields} Microwave suscepting SiC particles played a pivotal role in good densification retaining matrix grains <200 nm. - Abstract: The present work investigates the feasibility of microwave sintering to produce bulk metal-based nanocomposites having blend composition of Cu{sub 99}Cr{sub 1}, Cu{sub 94}Cr{sub 6}, Cu{sub 99}Cr{sub 1}-4 wt.% SiC and Cu{sub 94}Cr{sub 6}-4 wt.% SiC (average particle size {approx}30 nm). The 50 h ball-milled samples were uniaxially pressed, and then pellets were sintered at 800 deg. C, 900 deg. C and 1000 deg. C for a constant soaking period of 30 min by microwave sintering technique. Microstructural characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Sintered compacts resulted a highly densified compacts ({approx}95% relative density) while retaining ultra-fine grains (100-200 nm) in the matrix. The mechanical properties, namely, hardness and wear resistance, and electrical conductivity of the sintered specimens were also evaluated. The best combination of mechanical properties (e.g. hardness {approx}2.4 GPa) and electrical conductivity (60.3% of IACS) were obtained for Cu{sub 94}Cr{sub 6}-4 wt.% SiC sintered at 900 deg. C. This is possibly due to presence of ultra-fine grains in the bulk samples, good densification and proper bonding between particles. The results were analyzed in the light of interactions of microwaves between metallic matrix and microwave susceptive SiC particulates.

  12. HEAVY METALS (Hg, Cu, Mn, Cr e Ni CONTENTS IN THE RIO DAS PEDRAS LAGOON, MOJI-GUAÇU RIVER BASIN (SÃO PAULO STATE, BRAZIL = HISTÓRICO DA PRESENÇA DE METAIS PESADOS (Hg, Cu, Mn, Cr e Ni NA LAGOA RIO DAS PEDRAS, BACIA DO RIO MOJI-GUAÇU -SP, BRASIL

    Directory of Open Access Journals (Sweden)

    Claudinéia Raquel de Oliveira

    2003-01-01

    Full Text Available The presence of heavy metals in a sediment profile from the Rio das Pedras lagoon, located at the Moji-Guaçu river floodplain, São Paulo, was investigated. Samples were stratified at each 1 cm, sieved in 63 m m and digested in a strong acid solution (HNO3 + HF + HClO4 in PTFE bomb. The extracts were analyzed by emission plasma spectrometry (ICP-AES for Al, Cu, Mn, Cr and Ni contents. For Hg, the direct pyrolysis of samples and atomic fluorescence spectrometry detector AFS were employed. By using Al as a normalizer agent, an enrichment of metals concentration, with exception for Mn was observed. Average concentration for Cu (0.12 mg g-1 and Mn (1.12 mg g-1 were considered high in comparison to those concentrations in an unpolluted environment. Probably, these data are related to the agricultural activity (sugarcane plantation around the lagoon, or to the Moji-Guaçu river transport in the flood season. Hg, Cr and Niconcentrations were similar the those verified in unpolluted areas. The chronology inventigation, determined by the 210Pb technique, indicated that the 25 cm long sediment profile shows a 135 years of deposition history of the suspended material in this lagoon. = A presença de metais pesados em perfil de sedimento coletado na Lagoa Rio das Pedras, localizada na planície de inundação do rio Moji-Guaçu, São Paulo, foi investigada. Amostras estratificadas a cada 1 cm foram peneiradas a 63 m m e digeridas através de ataque ácido (HNO3 + HF + HClO4 em bombas de PTFE. Os extratos obtidos foram analisados quanto aos teores de Al, Cu, Mn, Cr e Ni por espectrometria de emissão de plasma (ICP-AES. Para Hg, empregou-se a pirólise direta da amostra e detecção por AFS. Utilizando-se Al como elemento normalizador, observou-se enriquecimento nos teores de metais pesados para anos recentes, exceto para Mn. As concentrações médias de Cu (0,12 mg g-1 e Mn (1,12 mg g-1 para amostras de sedimentos foram elevadas, em comparação

  13. Cr-Free Metallic-Ceramic Coatings

    Science.gov (United States)

    2014-11-01

    Cr -FREE METALLIC-CERAMIC COATINGS ASETS Defense 2014 Fort Myer, VA, November 18-20, 2014 Bruce McMordie Coatings for Industry 319...SNECMA Alseal® 5K Aluminum-Silicate Al-Silicate Coating System Now Available That Can Eliminate Hazards of Carcinogenic Cr +6 in Al...OMB control number. 1. REPORT DATE NOV 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Cr -Free Metallic

  14. The Microstructural Evolution of Vacuum Brazed 1Cr18Ni9Ti Using Various Filler Metals

    Directory of Open Access Journals (Sweden)

    Yunxia Chen

    2017-04-01

    Full Text Available The microstructures and weldability of a brazed joint of 1Cr18Ni9Ti austenitic stainless steel with BNi-2, BNi82CrSiBFe and BMn50NiCuCrCo filler metals in vacuum were investigated. It can be observed that an interdiffusion region existed between the filler metal and the base metal for the brazed joint of Ni-based filler metals. The width of the interdiffusion region was about 10 μm, and the microstructure of the brazed joint of BNi-2 filler metal was dense and free of obvious defects. In the case of the brazed joint of BMn50NiCuCrCo filler metal, there were pits, pores and crack defects in the brazing joint due to insufficient wettability of the filler metal. Crack defects can also be observed in the brazed joint of BNi82CrSiBFe filler metal. Compared with BMn50NiCuCrCo and BNi82CrSiBFe filler metals, BNi-2 filler metal is the best material for 1Cr18Ni9Ti austenitic stainless steel vacuum brazing because of its distinct weldability.

  15. Fabrication and mechanical properties of AlCoNiCrFe high-entropy alloy particle reinforced Cu matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian, E-mail: chenjian@xatu.edu.cn [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Niu, Pengyun; Wei, Ting [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Hao, Liang [College of Architecture and Civil Engineering, Xi' an University of Science and Technology, Xi' an 710054 (China); Liu, Yunzi [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Wang, Xianhui, E-mail: xhwang693@xaut.edu.cn [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an, Shaanxi 710048 (China); Peng, Yuli [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China)

    2015-11-15

    The AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying and the AlCoNiCrFe high-entropy alloy reinforced Cu matrix composites were subsequently fabricated by powder metallurgy. The phase constituents and morphology of the alloying powders were characterized by X-ray diffractometer and scanning electron microscope, the microstructures of the Cu base composites were characterized by scanning electron microscope and transmission electron microscope, and the compression tests were made as well. The results show that the AlCoNiCrFe high-entropy alloy can form after milling for 24 h. During sintering process, no grain growth occurs and no intermetallic phases present in the AlCoNiCrFe high-entropy alloy in the Cu base composite. Compression tests show that the AlCoNiCrFe high-entropy alloy has a better strengthening effect than metallic glasses and the yield strength of the Cu matrix composite reinforced with the AlCoNiCrFe high-entropy alloy is close to the value predicted by the Voigt model based on the equal strain assumption. - Graphical abstract: AlCoNiCrFe HEA has a better strengthening effect than metallic glasses for particulate reinforced metal matrix composites. The yield strength of the Cu base composite reinforced with the AlCoNiCrFe HEA is close to the upper bound calculated by Voigt model. - Highlights: • AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying. • A novel Cu base composite reinforced with AlCoNiCrFe was fabricated. • No grain growth and no intermetallic phase present in AlCoNiCrFe during sintering. • AlCoNiCrFe has a better strengthening effect than metallic glassy in composites.

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

    Institute of Scientific and Technical Information of China (English)

    Zhao Mei; Lin Guobiao; Wang Zidong; Zhang Maokui

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Wang Zidong

    2008-11-01

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

  18. Oxidation of two-phase Cu-Cr alloys with different microstructures

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The oxidation of PM Cu-50Cr, MA Cu-40Cr and MS Cu-40Cr alloys at 800  ℃ in 0.1  MPa O2 was studied. The most important difference of their oxidation behaviors is the formation of an exclusive chromia scale on the surface of the MS Cu-40Cr alloy and a continuous chromia layer beneath an outer CuO layer corresponding MA Cu-40Cr alloy, while a complex scale composing of CuO, Cu2O, Cu2Cr2O4 and Cr2O3 formed on the PM Cu-50Cr alloy. This result implies that alloy microstructure affects their oxidation behaviors largely. Microcrystalline structure provides numerous diffusion paths for reactive component chromium, shorter diffusion distance and rapid dissolution of Cr-riched second phase. All these favor the exclusive formation of the most stable oxide.

  19. The structural and electro-optical characteristics of AZO/Cr:Cu/AZO transparent conductive film

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Tien-Chai [Department of Electrical Engineering, Kun Shan University, No. 195, Kun-Da Road, Yung-Kang Dist., Tainan 71003, Taiwan, ROC (China); Huang, Wen-Chang, E-mail: wchuang@mail.ksu.edu.tw [Department of Electro-Optical Engineering, Kun Shan University, No. 195, Kun-Da Road, Yung-Kang Dist., Tainan 71003, Taiwan, ROC (China); Tsai, Fu-Chun [Department of Electro-Optical Engineering, Kun Shan University, No. 195, Kun-Da Road, Yung-Kang Dist., Tainan 71003, Taiwan, ROC (China)

    2015-08-31

    A novel triple-layered transparent conductive film, AZO/Cr:Cu/AZO (ACCA), was presented in the paper. The structural and electro-optical properties of the ACCA film were discussed. The thickness of the middle metal layer was constant and those of the AZO layers were varied. The ACCA film shows an obvious ZnO (002) c-axis preferential growth. No diffraction peaks related to Cr and Cu were observed through x-ray diffraction analysis. The middle Cr:Cu layer showed a thickness of 8.16 nm with a continuous and amorphous structure by the observation of a high-resolution transmission electron microscopy (HR-TEM). For the electro-optical characteristic, a best figure of merit (FOM) value of 3.54 × 10{sup −3} Ω{sup −1} with a corresponding transmittance of 85% was obtained at the thickness of 116 nm of ACCA film. The high FOM value of the film is due to the improvement of conductivity and small sacrifices of transparency. - Highlights: • A novel triple-layered transparent conductive film, AZO/Cr:Cu/AZO is developed. • Chromium is added to copper to reduce the oxidation–reduction reaction. • The film has a FOM of 3.54 × 10{sup −3} Ω{sup −1} with a corresponding transmittance of 85%. • The Cr:Cu layer shows a continuous and amorphous structure.

  20. Study on improvement of conductivity of Cu-Cr-Zr alloys

    Institute of Scientific and Technical Information of China (English)

    LI Huaqing; XIE Shuisheng; WU Pengyue; MI Xujun

    2007-01-01

    The influence of alloying, heat treatment, and plastic working on the performance of Cu-Cr-Zr alloys was investigated. The precipitated phases were characterized as Cr, Cu51Zr14 and Cu5Zr. Cu-Cr-Zr alloys demonstrate combination properties of high strength and high conductivity after solution treatment, aging treatment, and plastic deformation. Precipitation course of Cr is the main factor that influences the conductivity of Cu-Cr-Zr alloys, while adding Zr in the alloys adjusts the orientation relationship between Cr and matrix, and tends to increase the conductivity of aged Cu-Cr-Zr alloys after deformation.

  1. Structure, Magnetism, and Transport of CuCr2Se4 Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Bettinger, J.S.; Chopdekar, R.V.; Liberati, M.; Neulinger, J.R.; Chshiev, M.; Takamura, Y.; Alldredge, L.M.B.; Arenholz, E.; Idzerda,Y.U.; Stacy, A.M.; Butler, W.H.; Suzuki, Y.

    2007-04-01

    We report the successful growth of highly spin-polarized chalcogenide thin films of CuCr{sub 2}Se{sub 4}, which are promising candidates for spin-based electronic applications. We also present electronic structure calculations for CuCr{sub 2}Se{sub 4} that, together with magnetic and transport data, imply that the stoichiometric compound is a metallic ferromagnet with a relatively low density of hole-like carriers at the Fermi energy. These calculations also predict that a deficiency of Se will deplete the minority density of states at the Fermi energy perhaps leading to a half-metal. We have successfully grown thin films of CuCr{sub 2}Se{sub 4} by pulsed laser deposition on isostructural MgAl{sub 2}O{sub 4} substrates followed by an anneal in a Se-rich environment. X-ray diffraction confirms the structure of CuCr{sub 2}Se{sub 4} on MgAl{sub 2}O{sub 4} substrates as well as a secondary phase of Cr{sub 2}Se{sub 3}. X-ray absorption spectroscopy indicates that the chemical structure at the surface of the films is similar to that of bulk CuCr{sub 2}Se{sub 4} single crystals. Magnetization measurements indicate that these films saturate with a magnetic moment close to 5 {micro}{sub B} per formula unit and a T{sub c} above 400 K. X-ray magnetic circular dichroism shows that the magnetism persists to the surface of the film. Resistivity and Hall effect measurements are consistent with a p-type ferromagnetic metallic behavior and with the electronic structure calculations.

  2. CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure

    Science.gov (United States)

    Liu, Xingguang; Iamvasant, Chanon; Liu, Chang; Matthews, Allan; Leyland, Adrian

    2017-01-01

    CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also found that, with sufficient Cu content (>12 at.%), annealing at a moderately high temperature (e.g. 500 °C) leads to transportation of both Cu and Ag (even at relatively low concentrations of Ag, ≤3 at.%) from inside the coating to the coating surface, which resulted in significant reductions in friction coefficient, by over 50% compared to that of the substrate (from 0.31 to 0.14 with a hemispherical diamond indenter, and from 0.83 to 0.40 with an alumina ball counterface, respectively). Results indicate that the addition of both Cu and Ag (in appropriate concentrations) to nitrogen-containing chromium is a viable strategy for the development of 'self-replenishing' silver-containing thin film architectures for temperature-dependent solid lubrication requirements or antimicrobial coating applications.

  3. Feasibility of constructed wetland planted with Leersia hexandra Swartz for removing Cr, Cu and Ni from electroplating wastewater.

    Science.gov (United States)

    You, Shao-Hong; Zhang, Xue-Hong; Liu, Jie; Zhu, Yi-Nian; Gu, Chen

    2014-01-01

    As a low-cost treatment technology for effluent, the constructed wetlands can be applied to remove the heavy metals from wastewater. Leersia hexandra Swartz is a metal-accumulating hygrophyte with great potential to remove heavy metal from water. In this study, two pilot-scale constructed wetlands planted with L. hexandra (CWL) were set up in greenhouse to treat electroplating wastewater containing Cr, Cu and Ni. The treatment performance of CWL under different hydraulic loading rates (HLR) and initial metal concentrations were also evaluated. The results showed that CWL significantly reduced the concentrations of Cr, Cu and Ni in wastewater by 84.4%, 97.1% and 94.3%, respectively. High HLR decreased the removal efficiencies of Cr, Cu and Ni; however, the heavy metal concentrations in effluent met Emission Standard of Pollutants for Electroplating in China (ESPE) at HLR less than 0.3 m3/m2 d. For the influent of 5 mg/L Cr, 10 mg/L Cu and 8 mg/L Ni, effluent concentrations were below maximum allowable concentrations in ESPE, indicating that the removal of Cr, Cu and Ni by CWL was feasible at considerably high influent metal concentrations. Mass balance showed that the primary sink for the retention of contaminants within the constructed wetland system was the sediment, which accounted for 59.5%, 83.5%, and 73.9% of the Cr, Cu and Ni, respectively. The data from the pilot wetlands support the view that CWL could be used to successfully remove Cr, Cu and Ni from electroplating wastewater.

  4. Structural Investigations of Nanocrystalline Cu-Cr-Mo Alloy Prepared by High-Energy Ball Milling

    Science.gov (United States)

    Kumar, Avanish; Pradhan, Sunil Kumar; Jayasankar, Kalidoss; Debata, Mayadhar; Sharma, Rajendra Kumar; Mandal, Animesh

    2017-02-01

    Cu-Cr-Mo alloy could be a suitable candidate material for collector electrodes in high-power microwave tube devices. An attempt has been made to synthesize ternary Cu-Cr-Mo alloys by mechanical alloying of elemental Cu, Cr, and Mo powders, to extend the solid solubility of Cr and Mo in Cu, using a commercial planetary ball mill. For the first ternary alloy, a mixture of 80 wt.% Cu, 10 wt.% Cr, and 10 wt.% Mo was mechanically milled for 50 h. For the second ternary alloy, a mixture of 50 wt.% Cr and 50 wt.% Mo was mechanically milled for 50 h to obtain nanocrystalline Cr(Mo) alloy, which was later added to Cu powder and milled for 40 h to obtain Cu-20 wt.%Cr(Mo) alloy. Both nanocrystalline Cu-Cr-Mo ternary alloys exhibited crystallite size below 20 nm. It was concluded that, with addition of nanocrystalline Cr(Mo) to Cu, it was possible to extend the solid solubility of Cr and Mo in Cu, which otherwise was not possible by mechanical alloying of elemental powders. The resulting microstructure of the Cu-20 wt.%Cr(Mo) alloy comprised a homogeneous distribution of fine and hard (Cr, Mo) particles in a copper matrix. Furthermore, Cu-20 wt.%Cr(Mo) alloy showed better densification compared with Cu-10 wt.%Cr-10 wt.%Mo alloy.

  5. Photocatalytic hydrogen evolution over CuCrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Saadi, S.; Bouguelia, A.; Trari, M. [Laboratoire de Stockage et de Valorisation des Energies Renouvelables, Faculte de Chimie, U.S.T.H.B BP 32 Algiers (Algeria)

    2006-03-15

    We have been studying the technical feasibility of a photochemical H{sub 2} evolution based on a dispersion of CuCrO{sub 2} powder in aqueous electrolytes containing various reducing agents (S{sup 2-}, SO{sub 3}{sup 2-} and S{sub 2}O{sub 3}{sup 2-}). The title oxide combines a fair resistance to corrosion with an optimal band gap E{sub g} of 1.32eV. The intercalation of a small amount of oxygen should be accompanied by a partial oxidation of Cu{sup +} into Cu{sup 2+} implying a p-type semiconductivity. The S{sup 2-} oxidation inhibits the photocorrosion and the H{sub 2} evolution increases parallel to polysulfides S{sub n}{sup 2-} formation. Most of H{sub 2} is produced when p-CuCrO{sub 2} is connected to n-Cu{sub 2}O formed in situ. H{sub 2} liberation proceeds mostly on CuCrO{sub 2} while the oxidation of S{sup 2-} takes place over Cu{sub 2}O surface and the hetero system Cu{sub 2}O/CuCrO{sub 2} is optimized with respect to some physical parameters. The photoactivity is dependent on preparation conditions and lowering the synthesis temperature through nitrate route leads to an increase in specific surface area S{sub sp}. The photoelectrochemical H{sub 2} production is a multistep process where the rate determining step is the arrival of electrons at the interface because of their low mobility. Prolonged irradiation (>80min) leads to a pronounced decrease of the photoactivity; the tendency toward saturation is due to the undesired back reduction of polysulfides S{sub n}{sup 2-} in a closed system and to their strong absorption in the visible region (l{sub max}=520nm). (author)

  6. Electrochemical Behavior of Ion-Plated TiN and Cu-Cr Coatings

    Science.gov (United States)

    1993-09-01

    results show that Cu-Cr alloys containing up to about 25 atomic percent CR consist of single phase FCC structure . The alloys containing more than 60...19), curve 4 for CuCr(40), and curve 5 for Cu-Cr(85)]. Note that Curves 1, 2, and 3 are from FCC structure , curve 4 from dual-phase structure, and

  7. Microstructures and properties of Cr-Cu/W-Cu bi-layer composite coatings prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiaping; Feng, Xiaomei; Shen, Yifu; Chen, Cheng; Duan, Cuiyuan [Nanjing Univ. of Aeronautics and Astronautics (China). Dept. of Materials Science and Technology

    2016-06-15

    Cr-Cu/W-Cu bi-layer coatings with composite structures were fabricated by means of mechanical alloying. The Cr-Cu layer and the W-Cu layer were deposited successively and the as-synthesized bi-layer coating was made up of an inner Cr-Cu layer and an outer W-Cu layer. Microstructures, chemical and phase compositions of the as-prepared coatings were characterized. The results indicated that the bonding between the inner coating and the substrate was improved with the increase of Cu in the raw powder. The annealing treatment of the inner Cr-Cu layer was beneficial to the bonding between the inner Cr-Cu coating and the outer W-Cu coating layer. Mechanical properties such as microhardness, friction and wear resistance were tested. The as-synthesized coating could effectively improve the hardness and wear resistance of the Cu substrate.

  8. New approach in modeling Cr(VI) sorption onto biomass from metal binary mixtures solutions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chang [College of Environmental Science and Engineering, Anhui Normal University, South Jiuhua Road, 189, 241002 Wuhu (China); Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Fiol, Núria [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Villaescusa, Isabel, E-mail: Isabel.Villaescusa@udg.edu [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Poch, Jordi [Applied Mathematics Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain)

    2016-01-15

    In the last decades Cr(VI) sorption equilibrium and kinetic studies have been carried out using several types of biomasses. However there are few researchers that consider all the simultaneous processes that take place during Cr(VI) sorption (i.e., sorption/reduction of Cr(VI) and simultaneous formation and binding of reduced Cr(III)) when formulating a model that describes the overall sorption process. On the other hand Cr(VI) scarcely exists alone in wastewaters, it is usually found in mixtures with divalent metals. Therefore, the simultaneous removal of Cr(VI) and divalent metals in binary mixtures and the interactive mechanism governing Cr(VI) elimination have gained more and more attention. In the present work, kinetics of Cr(VI) sorption onto exhausted coffee from Cr(VI)–Cu(II) binary mixtures has been studied in a stirred batch reactor. A model including Cr(VI) sorption and reduction, Cr(III) sorption and the effect of the presence of Cu(II) in these processes has been developed and validated. This study constitutes an important advance in modeling Cr(VI) sorption kinetics especially when chromium sorption is in part based on the sorbent capacity of reducing hexavalent chromium and a metal cation is present in the binary mixture. - Highlights: • A kinetic model including Cr(VI) reduction, Cr(VI) and Cr(III) sorption/desorption • Synergistic effect of Cu(II) on Cr(VI) elimination included in the model • Model validation by checking it against independent sets of data.

  9. Estudo de metais pesados (Co, Cu, Fe, Cr, Ni, Mn, Pb e Zn na Bacia do Tarumã-Açu Manaus (AM Heavy metal (Co, Cu, Fe, Cr, Ni, Mn, Pb e Zn study in the Tarumã-Açu Basin Manaus (AM

    Directory of Open Access Journals (Sweden)

    Genilson Pereira Santana

    2007-01-01

    , heavy metal of battery, and others. It is discharged continually in landfill or at any place in city as Manaus. When non-treated the landfill leachate contaminates the superficial and groundwater water. The water and sediment samples were collected from the following streams: Igarapé do Matrinxã, Igarapé do Acará, Igarapé da Bolívia, Bacia do Tarumã-Açu and within Sanitary Landfill (Manaus Amazonas - Brazil in March of 2001. The water samples were filtered in Milipore 0.45 mm, treated with concentrated HNO3. The sediment samples were served to 0.053 mm and treated with concentrated HCl:HNO3 (1:3. The Co, Cu, Fe, Cr, Ni, Mn, Pb and Zn concentrations were determined by flame atomic absorption spectrometric. The results showed that heavy metals have concentration above the level permitted by Brazilian Environmental protection law (number 357/2005 CONAMA showing that landfill is the major responsible by environment impact of aquatic system. The principal component (PCA and hierarchical cluster (HCA analyses reveal that samples collected within of sanitary landfill have different characteristics from other site sampling. Additionally, HCA and PCA show a similarity between site samplings located out landfill it allows to sustain that the leachate is dissolved by whole aquatic system studied.

  10. Acceptable levels of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in soils, depending on their clay and humus content and cation-exchange capacity

    NARCIS (Netherlands)

    Haan, de S.; Rethfeld, H.; Driel, van W.

    1985-01-01

    Three sandy soils differing in humus content and three clay soils differing in clay content were supplied with heavy metals to determine which loading rate of each single metal should be regarded as critical from the viewpoint of crop yield and metal content dependent on soil cation exchange capacit

  11. Effects of extrusion on chromium precipitation in Cu-Cr alloy

    Institute of Scientific and Technical Information of China (English)

    范志康; 杨红旺; 梁淑华; 肖鹏

    2003-01-01

    Cu-Cr alloys containing Cr from 0.14% to 2.0% in mass were prepared as foils for TEM observation before and after being extruded. The results show that before extrusion, the spheroid or short bar chromium disperse in copper matrix of the Cu-Cr alloy, and the relationship between Cu and Cr follows the Nishiyama-Wasserman (NW) relationship, I.e. [110]Cu∥[001]Cr. After the Cu-Cr alloy was extruded at 860℃, dark field image along (224)Cu clearly shows that there are precipitated chromium particles in copper matrix. However, the SADP comprises only (112)Cu zone.

  12. Pressure- and Temperature-Dependent Study of Heusler Alloys Cu2MGa (M = Cr and V)

    Science.gov (United States)

    Gupta, Dinesh C.; Ghosh, Sukriti

    2017-04-01

    Full-potential computation of the electronic, magnetic, elastic and thermodynamic properties of Cu2MGa (M = Cr and V) alloys has been performed in the most stable Fm-3 m phase. The equilibrium lattice parameter is 5.9660 Å for Cu2CrGa and 5.9629 Å for Cu2VGa in the stable state. The application of mBJ potential has also found no energy gap in these alloys in either of the spin channels, hence they are metallic. The total and partial density of states, second-order elastic constants and their combinations are computed to show the electronic, magnetic, stability and brittle or ductile nature of these alloys, which are reported for the first time. Cauchy's pressure and Pugh's index predict Cu2CrGa to be brittle and Cu2VGa to be ductile. Both the materials are stiff enough to break. We have found that both the compounds are anisotropic, ferromagnetic and metallic in nature. We have used quasi-harmonic approximations to study the pressure and temperature variation of the thermodynamic properties of these alloys.

  13. Mechanical properties of Cr-Cu coatings produced by electroplating

    Science.gov (United States)

    Riyadi, Tri Widodo Besar; Sarjito, Masyrukan, Riswan, Ricky Ary

    2017-06-01

    Hard chromium coatings has long been considered as the most used electrodeposited coating in several industrial applications such as in petrochemistry, oil and gas industries. When hard coatings used in fastener components, the sliding contact during fastening operation produces high tensile stresses on the surface which can generate microcracks. For component used in high oxidation and corrosion environment, deep cracks cannot be tolerated. In this work, a laminated structure of Cr-Cu coating was prepared using electroplating on carbon steel substrates. Two baths of chrome and copper electrolyte solutions were prepared to deposit Cr as the first layer and Cu as the second layer. The effect of current voltages on the thickness, hardness and specific wear rate of the Cu layer was investigated. The results show that an increase of the current voltages increased the thickness and hardness of the Cu layer, but reduced the specific wear rate. This study showed that the use of Cu can be a potential candidate as a laminated structure Cr-Cu for chromium plating.

  14. Novel CuCr2O4 embedded CuO nanocomposites for efficient photodegradation of organic dyes

    Science.gov (United States)

    Mageshwari, K.; Sathyamoorthy, R.; Lee, Jeong Yong; Park, Jinsub

    2015-10-01

    Novel photocatalyst based on CuO-CuCr2O4 nanocomposites was synthesized for different Cr3+ concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr2O4 as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr3+ in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO-CuCr2O4 nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr2O4 loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO-CuCr2O4 nanocomposites can be attributed to the presence of CuCr2O4 as an electron acceptor, which improves the effective charge separation in CuO.

  15. Removal of As, Cd, Cr, Cu, Ni and Zn from polluted water using an iron based sorbent

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Wu, P.; Zhou, Y.

    2008-01-01

    In this study fixed-bed sorption filters are filled with an iron based sorbent (ferrosorp plus, FP) and used to remove a range of heavy metals (i.e. As, Cd, Cr, Cu, Ni, and Zn) from polluted water. It is found that FP is very effective at simultaneous removal of the heavy metals, and the magnitud...

  16. Removal of As, Cd, Cr, Cu, Ni and Zn from polluted water using an iron based sorbent

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Wu, P.; Zhou, Y.;

    2008-01-01

    In this study fixed-bed sorption filters are filled with an iron based sorbent (ferrosorp plus, FP) and used to remove a range of heavy metals (i.e. As, Cd, Cr, Cu, Ni, and Zn) from polluted water. It is found that FP is very effective at simultaneous removal of the heavy metals, and the magnitud...

  17. A novel method for amino starch preparation and its adsorption for Cu(II) and Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Dong Aiqin, E-mail: aegean.dong@gmail.com [Department of Chemistry, College of Science, Jiangxi Agricultural University, Zhimin Road, Nanchang 330045 (China); Xie Jie [Institute of Soil and Fertilizer and Environmental and Resources studies, Jiangxi Academy of Agricultural Sciences, Nanchang 330200 (China); Wang Wenmin; Yu Liping; Liu Qian [Department of Chemistry, College of Science, Jiangxi Agricultural University, Zhimin Road, Nanchang 330045 (China); Yin Yeping [Department of Chemistry, College of Science, Huazhong Agricultural University, Wuhan 430070 (China)

    2010-09-15

    A novel method was proposed to prepare amino starch by reacting ethylenediamine with previously synthesized dialdehyde starch. Different factors affecting the preparation, i.e., ethylenediamine concentration, ethylenediamine:dialdehyde starch molar ratio, pH, duration and temperature have been studied. The modified starch was characterized by IR spectroscopy, elemental analysis, X-ray diffraction and differential scanning calorimetry. The amino starch derivatives were evaluated as adsorbents. The adsorption activity for heavy metals such as Cu(II) and Cr(VI) by crosslinked amino starch was studied in terms of adsorption amount, kinetics and isotherm; and adsorbent reuse were also studied. Adsorption processes for Cu(II) and Cr(VI) on crosslinked amino starch fit a Langmuir isotherm, and adsorption for Cu(II) and Cr(VI) from aqueous solution was endothermic reactions. Crosslinked amino starch was very effective for the adsorption of Cu(II) and Cr(VI), and efficient in capacity, recycled.

  18. Texture of deformed Cu-Cr-Zr alloys

    Institute of Scientific and Technical Information of China (English)

    Huaqing Li; Shuisheng Xie; Xujun Mi; Pengyue Wu; Yanfeng Li

    2008-01-01

    The influences of plastic deformation, aging treatment, and alloying elements on the texture of Cu-Cr-Zr alloys were explored. The texture component and intensity of Cu-Cr-Zr alloys under various working conditions after aging treatment were characterized using the orientation distributing function (ODF). The influence of Zr content on the texture of Cu-Cr-Zr alloys was also analyzed. The reduction pass and deformation level were primary factors influencing the texture. Rolling texture appeared in a rolled plate and the fibrous textures of {111} and {001} were detected after 80% deformation. Fibrous texture with a main constituent of {111} improved the tensile strength of the alloy wire. The texture contents of {110} and {110} were predominated, whereas, those of {113} and {112} were in the minority in the Cu-Cr-Zr alloy with a higher Zr content (>0.5wt%).However, in the samples with a lower Zr content (, {112}, and {111} were in the majority.

  19. Corrosion behavior of CuCrNiAl alloy in HCl solutions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The corrosion behavior of a CuCrNiAl alloy in HCl solutions was studied by means of metallograph, XRD, SEM/EDX and TEM methods. The results show that in low concentration of HCl solutions, Cu of CuCrNiAl alloy is more easily subject to corrsion than Cr; the dechromisation of the CuCrNiAl alloy occurs at a certain concentration of HCl solutions, at the same time Al of CuCrNiAl alloy is subject to corrosion also. The dechromisation corrosion occurs initially at the interface between Cr phase and Cu phase, then it gradually extends Cr phase until Cr phase is dissolved completely. It is also revealed that the tendency of dechromisaion of the CuCrNiAl alloy increases with the increase in concentration and temperature of HCl solutions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, C., E-mail: ceaguilar@uach.c [Instituto de Materiales y Procesos Termomecanicos, Facultad de Ciencias de la Ingenieria, Universidad Austral de Chile, General Lagos 2086, Valdivia (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. L. Bernardo O' Higgins 3363, Santiago (Chile); Guzman, D. [Departamento de Metalurgia, Facultad de Ingenieria, Universidad de Atacama, Av. Copayapu 485, Copiapo (Chile); Rojas, P.A. [Escuela de Ingenieria Mecanica, Facultad de Ingenieria, Pontificia Universidad Catolica de Valparaiso, Av. Los Carrera 01567, Quilpue (Chile)

    2010-08-13

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

  1. Analysis of Breaking Characteristics of CuCrTa Contact Material%Cu Cr Ta触头材料的开断性能分析

    Institute of Scientific and Technical Information of China (English)

    王季梅

    2001-01-01

    文章介绍了真空灭弧室触头材料的发展方向和正在开发的Cu Cr Ta触头材料的金相结构和性能分析.对Cu Cr Ta触头材料与Cu W Al Fe、Cu Cr50触头材料进行了对比开断试验.从对比开断试验结果说明Cu Cr Ta触头材料能提高现有Cu W Al Fe和Cu Cr50触头材料的1.28~1.51倍.

  2. Trace metals (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) in feathers of Black-browed Albatross Thalassarche melanophrys attending the Patagonian Shelf.

    Science.gov (United States)

    Seco Pon, Juan Pablo; Beltrame, Ornela; Marcovecchio, Jorge; Favero, Marco; Gandini, Patricia

    2011-07-01

    We investigated the concentrations of cadmium, chromium, copper, iron, nickel, lead and zinc among feather tissues in sexes of Black-browed Albatross Thalassarche melanophrys killed in longliners off Argentina in 2005. We found no different metal concentration with sex for cadmium, copper, iron, lead and zinc in feathers of adult birds, though there were significant body-size differences between sexes. However, the concentrations of trace metals differed significantly among the type of feather within individual bird. The mean concentrations of copper, iron, and zinc in breast feathers of T. melanophrys were lower than those reported for the species from Georgias del Sur/South Georgia, the southern Indian Ocean and for other seabirds' worldwide. While cadmium fall within the known range of concentrations for bird feathers lead were not. Our results may be indicating that level of pollution in Patagonia may not be as negligible as previously thought at least for some trace metals. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Properties of CuCr contact materials with low chromium content and fine particles

    Institute of Scientific and Technical Information of China (English)

    曹辉; 王亚平; 郑志; 冼爱平

    2003-01-01

    The voltage withstanding capability and electric conductivity of CuCr contact materials with low chromium content and fine Cr particles were studied. The results show that the withstanding voltage has little relation with the Cr content for the melted-casting CuCr alloy within 15%-29% Cr content, and that the electric conductivity of the alloy increases with the decreasing of Cr content.

  4. Ab Initio Investigation on Cu/Cr Codoped Amorphous Carbon Nanocomposite Films with Giant Residual Stress Reduction.

    Science.gov (United States)

    Li, Xiaowei; Guo, Peng; Sun, Lili; Wang, Aiying; Ke, Peiling

    2015-12-23

    Amorphous carbon films (a-C) codoped by two metal elements exhibit the desirable combination of tribological and mechanical properties for widely potential applications, but are also prone to catastrophic failure due to the inevitable residual compressive stress. Thus far, the residual stress reduction mechanism remains unclear due to the insufficient understanding of the structure from the atomic and electronic scale. In this paper, using ab initio calculations, we first designed a novel Cu/Cr codoped a-C film and demonstrated that compared with pure and Cu/Cr monodoped cases, the residual stress in Cu/Cr codoped a-C films could be reduced by 93.6% remarkably. Atomic bond structure analysis revealed that the addition of Cu and Cr impurities in amorphous carbon structure resulted in the critical and significant relaxation of distorted C-C bond lengths. On the other hand, electronic structure calculation indicated a weak bonding interaction between the Cr and C atoms, while the antibonding interaction was observed for the Cu-C bonds, which would play a pivot site for the release of strain energy. Those interactions combined with the structural evolution could account for the drastic residual stress reduction caused by Cu/Cr codoping. Our results provide the theoretical guidance and desirable strategy to design and fabricate a new nanocomposite a-C films with combined properties for renewed applications.

  5. THE EFFECT OF RARE EARTH ELEMENTS ON Cr PRECIPITATIONS IN A Cu-0.8WT%Cr ALLOY

    Directory of Open Access Journals (Sweden)

    Gewang Shuai

    2011-05-01

    Full Text Available The microstructural evolution of Cu-based alloys during aging was studied using a quantitative metallographic method. Samples were cut from ingots of Cu-0.8wt%Cr and Cu-0.8wt%Cr-RE alloys. These were solution treated at 1000 ºC for 1.5h and subsequently quenched in water, then separately aged at 480 ºC for different durations. The microstructures were observed by optical microscope, and the characteristic geometric parameters of precipitated Cr phase, including volume fraction VV, face density NA, mean diameter and roundness, were measured. These data provided more details about the process of aging. The results showed that precipitation of Cr phase occurred in the form of particles during aging. Rare earth elements promoted the precipitation of Cr phase and dispersed Cr particles. The phenomenon of overaging came earlier in Cu-Cr-RE than in Cu-Cr. In the present work, the optimal aging time at 480 ºC was 2 hrs for the Cu-0.8wt%Cr-RE alloy and 3 hours for the Cu-0.8wt%Cr alloy.

  6. Aging Behavior of Cu-Cr-Zr-Ce Alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LIU Ping; SU Juan-hua; TIAN Bao-hong; LI Wei

    2004-01-01

    The aging properties of Cu-0.35Cr-0.038Zr-0.055Ce alloy are studied. The results show that can obtain higher electrical conductivity and microhardness after solutioned at 920℃for lh, and aged at 500℃. The process of precipitation of the secondary phase can be accelerated with cold deformation before aging, so properties of the alloy are improved.Upon aging at 500℃ for 30 minutes after 60% cold deformation, the values of electrical conductivity and microhardness are69.0%IACS and 152HV respectively, but they are only 66.2%IACS and 136HV upon directly aging after solution. With the addition of a trace of rare earth element Ce, the value of microhardness of Cu-0.35Cr-0.038Zr alloy increases 18~25HV,while the value of electrical conductivity drops a little.

  7. [Response of Nostoc flageliforme cell to Cu2+, Cr2+ and Pb2+ stress].

    Science.gov (United States)

    Guo, Jinying; Shi, Mingke; Zhao, Yanli; Ren, Guoyan; Yi, Junpeng; Niu, Leilei; Li, Juan

    2013-06-04

    This study aimed to investigate the effects of Cu2+, Cr2+ and Pb2+ stress on Nostoc flagelliforme cell. The response of Nostoc flagelliforme cell was analyzed under the stress. The modified BG11 culture medium containing different heavy metal ions of 0, 0.1, 1.0, 10, 100 mg/L was used to cultivate Nostoc flagelliforme cell at 25 degrees C and light intensity of 80 micromol/(m x s). Electrolyte leakage, the activities of superoxide dismutase, the content of malondialdehyde, proline, soluble protein and trehalose were analyzed. Under 1 - 100 mg/L Cu2+, Cr2+ and Pb2+ stress, electrolyte leakage and malondialdehyde contents in Nostoc flagelliforme cell were higher than those in the control group during heavy metal ions stress. Meanwhile, superoxide dismutase activity increased slightly under 10 mg/L, but was lower afterwards. The contents of proline, soluble protein and trehalose increased under 10 mg/L heavy metal ions stress, while declined under extreme heavy metal ions stress (100 mg/L). Nostoc flagelliforme cell has resistance to low heavy metal ions stress, but is damaged badly under extreme heavy metal ions stress.

  8. STUDY ON MORPHOLOGY OF CHROMIUM IN CHILLED Cu-0.14%-2.0%Cr ALLOYS

    Institute of Scientific and Technical Information of China (English)

    H.W.Yang; Z.K.Fan

    2004-01-01

    The morphology of chromium in chilled Cu-Cr alloys with 0.14%-2.0% Cr has been studied. The results showed that eutectic Cr phase takes a fibrous shape, and pre-eutectic Cr is dendritic in the studied chilled Cu-Cr alloy. During solute treatment of the eutectic and super-eutectic Cu-Cr alloys, only part of chromium particles dissolved in copper phase,some fiber and dendritic chromium still remained. Forging before solute treatment can reduce the size of primary Cr particles, which benefits the aging structure.

  9. Spin state and orbital ordering in CuCr2O4 investigated by NMR

    Science.gov (United States)

    Jo, Euna; Kang, Byeongki; Kim, Changsoo; Kwon, Sangil; Lee, Soonchil

    2013-09-01

    63,65Cu and 53Cr nuclear magnetic resonance spectra for CuCr2O4 were measured at various magnetic fields and temperatures. The microscopic evidence of orbital ordering in CuCr2O4 was obtained from a dipolar hyperfine field, NQR, and magnetic anisotropy analysis of the linewidth broadening of the Cu and Cr NMR spectra measured in the external magnetic field. The energy gap in the dispersion relation of the spin wave excitation was measured from the temperature dependence of the resonance frequency of Cu and Cr ions in CuCr2O4. The energy gap of the Cu ions is about 10 K (± 5 K), and that of the Cr ions is about 40 K (± 5 K). These values imply that the spin-orbit coupling of Cr ions is stronger than that of Cu ions related to the orbital ordering in CuCr2O4. The magnetic field dependence of the Cr NMR frequency shows that the angle between the Cr3+ magnetic moment and the Cu2+ magnetic moment is about 98∘ (± 2∘).

  10. Biosorption of Cr(III), Cr(VI), Cu(II) ions by intact cells of Spirulina platensis

    OpenAIRE

    Gelagutashvili, E.; Bagdavadze, N.; Rcheulishvili, A.

    2017-01-01

    The absorption characteristics of Cr(III), Cr(VI), Cu(II) ions on intact living cells Spirulina platensis (pH9.6) were studied by using a UV-VIS spectrophotometer. Also biosorption of these ions with cyanobacteria Spirulina platensis were studied using equilibrium dialysis and atomic absorption analysis.It was shown, that the absorption intensity of Spirulina platensis decreases, when Cr(III), Cr(VI), Cu(II) ions are added. Significant difference between the absorption intensity for Cu(II) Sp...

  11. Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments--a review.

    Science.gov (United States)

    Kumpiene, Jurate; Lagerkvist, Anders; Maurice, Christian

    2008-01-01

    The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxy-hydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays.

  12. Cu Diffusion in Co/Cu/TiN Films for Cu Metallization

    Institute of Scientific and Technical Information of China (English)

    Xiuhua CHEN; Xinghui WU; Jinzhong XIANG; Zhenlai ZHOU; Heyun ZHAO; Liqiang CHEN

    2006-01-01

    Some information on how to use in-situ determined diffusion coefficient of Cu to make barrier layer of Cu metallization in ultra large scale integrations (ULSIs) was provided. Diffusion coefficients of Cu in Co at low temperature were determined to analyze Cu migration to Co surface layer. The diffusion depths were analyzed using X-ray photoelectron spectroscopy (XPS) depth profile to investigate the diffusion effect of Cu in Co at different temperatures. The possible pretreatment temperature and time of barrier layer can be predicted according to the diffusion coefficients of Cu in Co.

  13. Improvement of tensile properties of pure Cu and CuCrZr alloy by cryo-rolling process

    Energy Technology Data Exchange (ETDEWEB)

    Ihira, Ryota; Gwon, Hyoseong; Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp; Konishi, Satoshi

    2016-11-01

    Highlights: • We investigated the effect of cryo-rolling process to Cu and CuCrZr alloy by tensile test and EBSD. • Cryo-rolling process simaltaneously increased strength and ductility of Cu as previously reported. • Cryo-rolling process increased strength of CuCrZr alloy without loss-of-ductility compared with conventional cold-rolling process. • We observed heterogeneous grain size distribution in cryo-rolled Cu but not in cryo-rolled CuCrZr alloy. • We found temperature-transition of texture formation in the rolled CuCrZr alloy. - Abstract: The present study investigates the effect of cryo-rolling process, i.e. cold-rolling at liquid-nitrogen temperature followed by heat treatment, on tensile properties of pure copper and precipitation-hardened CuCrZr alloy. The cryo-rolling process resulted in a simultaneous improvement of strength and ductility of pure copper. On the other hand, a cryo-rolled CuCrZr alloy showed higher tensile strength but comparable ductility with a conventional cold-rolled CuCrZr alloy. Microstructural analysis indicates that the drastically-beneficial effect of cryo-rolling on pure copper may be due to its heterogeneous size distribution of grains which consist of cryo-rolled fine grains, residual cryo-rolled grains and recrystallized coarse grains. The modest but certain benefit of cryo-rolling on CuCrZr alloy can be explained by different texture formation compared with conventional cold-rolling. Effect of neutron irradiation on tensile properties of cryo-rolled CuCrZr alloy is also examined.

  14. Radiation induced decontamination of Cr(Ⅵ), Cu(Ⅱ) and phenol in some tannery effluents

    Institute of Scientific and Technical Information of China (English)

    Hasan M.KHAN; Abdul MAHMOOD

    2007-01-01

    Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high concentrations of Cr(Ⅵ) (2.7-12.6 mg/L), Cu(Ⅱ) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A new technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(Ⅵ), Cu(Ⅱ) and phenol associated with tannery effluents to the permitted values. It was observed that concentration of Cr(Ⅵ) in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy. A radiation dose of 2.5 kGy was required to remove more than 95% of Cu(Ⅱ) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose.

  15. Microstructures and properties of cold drawn and annealed submicron crystalline Cu-5%Cr alloy

    Institute of Scientific and Technical Information of China (English)

    HE Wen-xiong; YU Yang; WANG Er-de; SUN Hong-fei; HU Lian-xi; CHEN Hui

    2009-01-01

    The microstructures and properties after cold drawing and subsequent annealing of submicron crystalline Cu-5%Cr (mass fraction) alloy were investigated. The results show that, the microstructure of submicron crystalline Cu-5%Cr can be further refined by cold drawing. After cold drawing, the grains of Cu-5%Cr alloy with grain size of 400-500 nm can be refined to be cellular structures and subgrains with size of 100-200 nm. Both strength and ductility of Cu-5%Cr alloy can be enhanced by cold drawing, and the optimal mechanical properties can be achieved with drawing deformation increasing. It is suggested that dislocation glide is still the main mechanism in plastic deformation of submicron crystalline Cu-5%Cr, but grain boundary slide and diffusion may play more and more important roles with drawing deformation increasing. When the cold drawn Cu-5%Cr wires are annealed at 550 ℃, fine recrystal grains with grain size of 200-300 nm can be obtained. Furthermore, there are lots of fine Cr particles precipitated during annealing, by which the recrystallization softening temperatures of the cold drawn Cu-5%Cr wires can be increased to 480-560 ℃. Due to the fact that Cr particles have the effect of restricting Cu grains growth, a favorable structural thermal stability of the submicron crystalline Cu-5%Cr can be achieved, and the submicron grained microstructure can be retained at high temperature annealing.

  16. Influence of deformation and heat treatment on electrical conductivity of CuMoCr alloy

    Institute of Scientific and Technical Information of China (English)

    XIONG Xue-hui; LIU Lin; YUE Xue-qing; LIU Jian-hua; ZHANG Rui-jun

    2009-01-01

    The solution heat treatment, cold deformation and subsequent aging were performed on CuMoCr al-loy. And the influence of deformation and aging treatment on the electrical conductivity of CuMoCr alloy was studied through metallograph, transmission electron microscopy (TEM) and electrical conductivity measure-ment. Results show that deformation without subsequent aging can reduce the electrical conductivity of CuMoCr alloy, but deformation followed by the optimum aging treatment can effectively improve the electrical conductivi-ty of CuMoCr alloy. Aging at 500℃ for 4 h after 80% deformation, the much better electrical conductivity of CuMoCr alloy can be obtained. Reduction of Cr content in the Cu matrix could be the reason for the enhance-ment of electrical conductivity.

  17. Fatigue Property Study of 05Cr17Ni4Cu4Nb Steel Weld Joints%05Cr17Ni4Cu4Nb钢焊接接头的疲劳性能

    Institute of Scientific and Technical Information of China (English)

    刘福广; 李振伟; 冯琳杰; 李太江; 王琦; 王彩侠; 李巍

    2013-01-01

    Fatigue property of 05Cr17Ni4Cu4Nb steel used for last stage rotor blade of steam turbine weld joints was studied by means of four-point-bending fatigue test and S-N curve was obtained, compared with parent material at the same time. Results showed that conditional fatigue limit of o5Cr17Ni4Cu4Nb steel weld joints can reach 90%of parent metal using optimized weld and post weld heat treatment process. SEM observation of fracture surface of fatigue specimen showed that the micro-defect at surface or near surface and microstructure heterogeneity are the main influence factors of 05Cr17Ni4Cu4Nb weld joints fatigue property.%采用四点弯曲疲劳试验方法,研究了05Cr17Ni4Cu4Nb汽轮机低压末级动叶片用钢焊接接头的疲劳性能,绘制了该钢焊接接头的S-N曲线,并与05Cr17Ni4Cu4Nb钢母材进行了对比。研究结果表明,采用优化的焊接、热处理工艺,05Cr17Ni4CuNb钢焊接接头的条件疲劳极限可以达到母材的90%以上。疲劳试样断口的扫描电子显微镜观察发现,焊缝表面或近表面的显微缺陷及接头的组织不均匀性是影响05Cr17Ni4Cu4Nb钢焊接接头接头疲劳性能的主要因素。

  18. Catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid under an irradiation of simulated solar light.

    Science.gov (United States)

    Li, Ying; Chen, Cheng; Zhang, Jing; Lan, Yeqing

    2015-05-01

    The catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid with simulated solar light was investigated. The results demonstrated that Cu(II) could significantly accelerate Cr(VI) reduction and the reaction obeyed to pseudo zero-order kinetics with respect to Cr(VI). The removal of Cr(VI) was related to the initial concentrations of Cu(II), citric acid, and the types of organic acids. The optimal removal of Cr(VI) was achieved at pH 4, and the rates of Cu(II) photocatalytic reduction of Cr(VI) by organic acids were in the order: tartaric acid (two α-OH groups, two -COOH groups)>citric acid (one α-OH group, three -COOH groups)>malic acid (one α-OH group, two -COOH groups)>lactic acid (one α-OH group, one -COOH group)≫succinic acid (two -COOH groups), suggesting that the number of α-OH was the key factor for the reaction, followed by the number of -COOH. The formation of Cu(II)-citric acid complex could generate Cu(I) and radicals through a pathway of metal-ligand-electron transfer, promoting the reduction of Cr(VI). This study is helpful to fully understanding the conversion of Cr(VI) in the existence of both organic acids and Cu(II) with solar light in aquatic environments.

  19. Effect of component substitution on the microstructure and mechanical properties of MCoCrFeNiTix (M = Cu,Al) solid-solution alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    MCoCrFeNiTix (M = Cu,Al;x:molar ratio,x = 0,0.5) alloys were prepared using the new alloy-design strategy of equal-atomic ratio and high entropy.By the component substitution of Al for Cu,the microstructure changes from the face-centered cubic solid solution of original CuCoCrFeNiTix alloys to the body-centered cubic solid solution of AICoCrFeNiTix alloys.Compared with original CuCoCrFeNiTix alloys,AICoCrFeNiTix alloys keep the similar good ductility and simultaneously possess a much higher compressive strength,which are even superior to most of the reported high-strength alloys like bulk metallic glasses.

  20. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17%Cr and Cu-17%Cr-5%Al. Part 1; Oxidation Kinetics

    Science.gov (United States)

    Raj. Sai V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. These observations reveal that Cu- 17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9 9.5 kJ mol-1. In contrast, the oxidation kinetics for the Cu-17%Cr- 5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%CR- 5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.

  1. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17 Percent Cr and Cu-17 Percent Cr-5 Percent Al. Part 1; Oxidation Kinetics

    Science.gov (United States)

    Raj, S. V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. These observations reveal that Cu-17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9+/-9.5 kJ/mol. In contrast, the oxidation kinetics for the Cu-17%Cr-5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%CR-5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.

  2. Thermodynamic analysis of the simple microstructure of AlCrFeNiCu high-entropy alloy with multi-principal elements

    Institute of Scientific and Technical Information of China (English)

    Aumin LI; Xiyan ZHANG

    2009-01-01

    AlCrFeNiCu high-entropy alloy (THA) was synthesized by the arc melting and casting method. The alloy exhibits simple FCC and BCC solid solution phases rather than intermetallic compounds. The reason is that the Gibbs free energy of mixing of the equimolar A1CrFeNiCu alloy is smaller than that of inter-metallic compounds by calculation according to the Miedema model.

  3. 改性沸石对废水中Cu2+、Cr3+的去除作用研究%Research on the removing effect of modified clinoptilolite on Cu2+and Cr3+from wastewater

    Institute of Scientific and Technical Information of China (English)

    张义婕; 司志华; 胡晓静; 石玉坤; 朱宝林; 郑晓广; 黄唯平

    2014-01-01

    The modified clinoptilolite,which was obtained by NaOH alkali fusion-hydrothermal treatment process, has been used as an adsorption exchanger. Adsorption treatment of heavy metal ions, represented by Cu2+,and Cr3+in simulated wastewater is conducted. Under different conditions,such as adsorption time, dosages and initial concentration,the removing effects of modified clinoptilolite on Cu2+and Cr3+from water samples are studied. The experimental results show that the mass ratio of modified clinoptilolite and Cu2+,Cr3+in water samples is 18.75∶1 and 13.33∶1,respectively,the Cu2+and Cr3+removing rates are 88.0%and 87.4%,respectively. It is a rapid adsorption equilibrium process. In addition,the regeneration experiment on modified chinoptilolite,which was saturated with Cu2+by sodium chloride solution and sodium chloride solution+ammonia ,has been accomplished. The regenerating rate is pretty high and modified clinoptilolite can be used repeatedly many times.%用NaOH碱熔-水热法处理得到的改性斜发沸石作为吸附交换剂,对模拟废水中以Cu2+、Cr3+为代表的重金属离子进行吸附处理。研究了不同吸附时间、投加量以及初始浓度条件下,改性斜发沸石对Cu2+、Cr3+的去除效果。实验结果表明:改性沸石与水样中Cu2+、Cr3+的质量比分别为18.75∶1、13.33∶1时,对Cu2+、Cr3+的去除率分别达88.0%、87.4%,且为快速吸附平衡过程。此外,用NaCl溶液和NaCl溶液加氨水对吸附Cu2+饱和的改性沸石进行再生实验,再生率较高,改性斜发沸石可以多次重复利用。

  4. Photocatalytic removal of M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) over new catalyst CuCrO(2).

    Science.gov (United States)

    Ketir, W; Bouguelia, A; Trari, M

    2008-10-30

    The metal ions M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) are potentially toxic. Their electro deposition has been carried out in aqueous air-equilibrated CuCrO(2) suspension upon visible illumination. The delafossite CuCrO(2) is p-type semiconductor characterized by a low band gap (1.28 eV) and a long-term chemical stability. The corrosion rate is found to be 10(-2) micromol m(-2)month(-1) in aqua regia. The oxide has been elaborated through nitrate route where the specific surface area is increased via the surface/bulk ratio. A correlation exists between the dark M(2+) adsorption, the redox potential of M(2+/0) couple and the conduction band of CuCrO(2) positioned at -1.06 V(SCE). Ag(+) cannot be photoreduced because of its positive potential located far above the valence band. By contrast, Zn(2+) is efficiently deposited due to the large driving force at the interface. The improved photoactivity of copper with a deposition percentage (90%) is attributed to the strong dark adsorption onto the surface catalyst. The results indicate a competitive effect with the water reduction; it has been observed that the M(2+) deposition goes parallel with the hydrogen evolution. Such behavior is attributed to the low H(2) over voltage when ultra fine aggregate of M islands are photodeposited onto CuCrO(2) substrate.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation); Abramov, V. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation); Rodin, M. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation)

    1996-10-01

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

  6. Effects of deformation on microstructures and properties of submicron crystalline Cu-5%Cr alloy

    Institute of Scientific and Technical Information of China (English)

    HE Wen-xiong; WANG Er-de; CHEN Hui; YU Yang; LIU Jing-lei

    2007-01-01

    Warm extrusion of submicron crystalline Cu-5%Cr from 100 ℃ to 600 ℃ was investigated. The effects of different extrusion ratios and different extrusion temperatures on microstructures and properties of submicron crystalline Cu-5%Cr were studied. The microstructures of the extruded Cu-5%Cr were characterized by backscattered electron images(BSE) and transmission electron microscopy(TEM). The mechanical properties of the extruded Cu-5%Cr were measured by means of microhardness and tension test. The results show that, the deformation, dynamic recovery and dynamic recrystallization of the extruded Cu-5%Cr are mainly produced in Cu matrix. The higher extrusion ratio leads to more uniform microstructure and finer Cu grains. When being extruded in the range of 100-600 ℃, dynamic recovery of Cu is the dominant process, and dynamic recrystallization of Cu occurred above 300 ℃ is far from end. The most part of microstructure of as-extruded Cu-5%Cr is subcrystallines produced by dynamic recovery, only a few recrystallines exist, and the average size of these grains is not larger than 400 nm. With extrusion temperature rising, the tensile strength and microhardness of Cu-5%Cr decrease, and elongation increases gradually.

  7. Removal of Cu, Cr, Ni, Zn, and Cd from electroplating wastes and synthetic solutions by vermicompost of cattle manure.

    Science.gov (United States)

    Jordão, Cláudio Pereira; Pereira, Madson de Godoi; Einloft, Rosilene; Santana, Marlete Bastos; Bellato, Carlos Roberto; de Mello, Jaime Wilson Vargas

    2002-01-01

    This study was undertaken to evaluate the retention of Cu, Cr, Ni, Zn, and Cd under laboratory conditions from synthetic solution and electroplating wastes by vermicompost. A glass column was loaded with vermicompost, and metal solutions were passed through it. Metal concentrations were then measured in the eluate in order to evaluate the amounts retained by the vermicompost. Measurements of pH, metal concentrations, moistness, organic matter and ash contents, and infrared and XRD spectroscopy were used for vermicompost characterisation. Vermicompost residues obtained from this process were used for plant nutrition in eroded soil collected from a talus near a highway. Metal retention (in g of metal/kg of vermicompost) from effluents ranged from 2 for Cr and Zn to 4 in the case of Ni. In synthetic solutions, the values for metal retention were 4 for Cd and Zn, 6 for Cu and Ni, and 9 for Cr. The results also showed that metal concentrations in the purified effluents were below the maximum values established for waste discharges into rivers by the Brazilian Environmental Standards. The relatively high available Cd concentration of the vermicompost residue resulted in plant damage. This effect was attributed to the presence of Cd in the synthetic solution passed through the vermicompost. The data obtained do not give a complete picture of using vermicompost in cultivated lands, but such values as are determined do show that it can be suitable to remove heavy metals from industrial effluents.

  8. Biosorption of binary mixtures of Cr(III and Cu(II ions by Sargassum sp

    Directory of Open Access Journals (Sweden)

    Silva E.A.

    2003-01-01

    Full Text Available The adsorption of two metal ions, Cr(III and Cu(II, in single-component and binary systems by Sargassum sp., a brown alga, was studied. Equilibrium batch sorption studies were carried out at 30ºC and pH 3.5. Kinetic tests were done for a binary mixture (chromium + copper for a contact time of 72 hours to guarantee that equilibrium was reached. The monocomponent equilibrium data obtained were analyzed using the Langmuir and Freundlich isotherms. The binary equilibrium data obtained were described using four Langmuir-type and Freundlich isotherms. The F-test showed a statistically significant fit for all binary isotherm models. The parameters for isotherms of the Langmuir-type were used to determine the affinity of one metal for the biosorbent in the presence of another metal. The chromium ion showed a greater affinity for Sargassum sp. than the copper ion.

  9. Arc Erosion Characteristics of Nanocrystalline CuCr50 Contact Material%纳米CuCr50触头材料电弧侵蚀特性

    Institute of Scientific and Technical Information of China (English)

    赵来军; 李震彪; 王珂; 邱安宁; 李慧杰

    2012-01-01

    近年来,纳米CuCr触头材料在截流水平、耐压能力等方面的表现优于微晶CuCr触头材料.笔者利用真空触点模拟装置和基于虚拟仪器的电器电寿命测试系统,研究了直流低电压、小电流下的纳米CuCr50触头材料的电孤侵蚀量与分断燃弧时间和触头表面形貌之间的关系,同时采用两种微晶CuCr50触头材料作为对比.利用电光分析天平纳米CuCr50触头材料的侵蚀量,利用电子扫描显微镜测量触头表面形貌.结果表明:纳米CuCr50触头材料的平均分断燃孤时间和侵蚀量均高于两种微晶CuCr50触头材料.纳米CuCr50触头表面Cr颗粒细化及均匀分布,有利于分散电弧.纳米CuCr50阴极触头表面电弧烧蚀比较均匀,而两种微晶CuCr50触头阴极表面电弧局部烧蚀严重,出现明显的凹坑侵蚀.%In recent years, nanocrystalline copper-chromium(Cu-Cr) contact material performed well in high withstand voltage, low chopping current, and so forth. Therefore, it has a big potential application in vacuum switches. The objective of this paper was to investigate vacuum arc erosion characteristics of a nanocrystalline CuCr (Cr50 wt.%) contact material. The vacuum contact simulation device was used to conduct contact materials arc erosion tests, and voltage waveforms of making and breaking arcs between the electrodes were recorded with LabVTEW. Using electric-light analytical balance and scanning electron microscopy, the mass loss and the surface structure of CuCr contact materials were obtained. Experiments indicated that the average break arcing time and the contact mass loss of nanocrystalline CuCr50 material were higher than those of two microcrystalline CuCr50 materials. The eroded contact surface structure showed a clear difference that the cathode contact surface of nanocrystalline CuCr50 contact material was uniform, while each cathode contact surface of two microcrystalline CuCr50 materials had an obvious arc erosion pit.

  10. Bioaccumulation of Pb, Cd, Cu, and Cr by Porphyridium cruentum (S.F. Gray Nägeli

    Directory of Open Access Journals (Sweden)

    Tri Retnaningsih Soeprobowati

    2013-06-01

    Full Text Available The red microalgae Porphyridium cruentum (S.F. Gray Nägeli usually was used as feeds, a pigment for food and cosmetic, and antiviral activity that might be became industrial interest. Similar to another microalgae, P. cruentum has an ability to remediate heavy metals pollution, however research on it still limited. This research was conducted in order to find out the the accumulation of Pb, Cd, Cr, and Cu on the P. cruentum. A laboratory experiment were developed with different concentrations. Based on this research, P. cruentum with the treatment of 1 mg/L had reduced higher Cu, Pb, Cd, and Cr concentrations rather than 3 and 5 mg/L concentrations, respectively. This was also similar to the BCF, that in day 8 in order of Cu > Cr > Cd > Pb, respectively; however, in day 15 was Cu > Pb > Cd > Cr. The length of treatment influenced BCF value. P. cruentum was good for bioremediation of heavy metal pollution, with the advantage of the short of accumulation time.

  11. Short-range Ferromagnetism in Alloy Ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    DEFF Research Database (Denmark)

    Thanh, P. Q.; Hoa, N. Q.; Chau, N.

    2014-01-01

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic...

  12. The effect of irradiation on tensile properties and fracture toughness of CuCrZr and CuCrNiSi alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kalinin, G.M., E-mail: gmk@nikiet.ru [OJSC ' NIKIET' , P.O.B. 788, Moscow 101000 (Russian Federation); Artyugin, A.S.; Yvseev, M.V.; Shushlebin, V.V.; Sinelnikov, L.P. [OJSC ' IRM' , Zarechnyi, 624250 Sverdlovsk Region (Russian Federation); Strebkov, Yu.S. [OJSC ' NIKIET' , P.O.B. 788, Moscow 101000 (Russian Federation)

    2011-10-01

    This paper deals with the effect of irradiation on tensile properties and fracture toughness of CuCrZr and CuCrNiSi alloys, considered for use in some in-vessel components of ITER, where a combination of high strength and heat conduction is essential. The heat treatments were: -CuCrZr, quenching in water after annealing at 950 {sup o}S, cold worked 40-45%, and aged at 475-500 {sup o}S for 3 h. -CuCrNiSi, quenching in water after annealing at 980 {sup o}S and aged for 4 h at 460 {sup o}S. Specimens were irradiated in the IVV-2 reactor at {approx}200 {sup o}S and with irradiation damage of 0.15 and 0.27 dpa. Post-irradiation tests were carried out to assess the tensile properties and fracture toughness of the materials. The tests results show that CuCrNiSi has better strength and retains higher ductility after irradiation, but has somewhat lower crack resistance than CuCrZr.

  13. Removal of Cu, Zn, Pb, and Cr from Yangtze Estuary Using the Phragmites australis Artificial Floating Wetlands.

    Science.gov (United States)

    Huang, Xiaofeng; Zhao, Feng; Yu, Gao; Song, Chao; Geng, Zhi; Zhuang, Ping

    2017-01-01

    Contamination of heavy metals would threaten the water and soil resources; phytoremediation can be potentially used to remediate metal contaminated sites. We constructed the Phragmites australis artificial floating wetlands outside the Qingcaosha Reservoir in the Yangtze Estuary. Water characteristic variables were measured in situ by using YSI Professional Pro Meter. Four heavy metals (copper, zinc, lead, and chromium) in both water and plant tissues were determined. Four heavy metals in estuary water were as follows: 0.03 mg/Kg, 0.016 mg/Kg, 0.0015 mg/Kg, and 0.004 mg/Kg. These heavy metals were largely retained in the belowground tissues of P. australis. The bioaccumulation (BAF) and translation factor (TF) value of four heavy metals were affected by the salinity, temperature, and dissolved oxygen. The highest BAF of each metal calculated was as follows: Cr (0.091 in winter) > Cu (0.054 in autumn) > Pb (0.016 in summer) > Zn (0.011 in summer). Highest root-rhizome TF values were recorded for four metals: 6.450 for Cu in autumn, 2.895 for Zn in summer, 7.031 for Pb in autumn, and 2.012 for Cr in autumn. This indicates that the P. australis AFW has potential to be used to protect the water of Qingcaosha Reservoir from heavy metal contamination.

  14. Removal of Cu, Zn, Pb, and Cr from Yangtze Estuary Using the Phragmites australis Artificial Floating Wetlands

    Science.gov (United States)

    Zhao, Feng; Yu, Gao; Song, Chao; Geng, Zhi

    2017-01-01

    Contamination of heavy metals would threaten the water and soil resources; phytoremediation can be potentially used to remediate metal contaminated sites. We constructed the Phragmites australis artificial floating wetlands outside the Qingcaosha Reservoir in the Yangtze Estuary. Water characteristic variables were measured in situ by using YSI Professional Pro Meter. Four heavy metals (copper, zinc, lead, and chromium) in both water and plant tissues were determined. Four heavy metals in estuary water were as follows: 0.03 mg/Kg, 0.016 mg/Kg, 0.0015 mg/Kg, and 0.004 mg/Kg. These heavy metals were largely retained in the belowground tissues of P. australis. The bioaccumulation (BAF) and translation factor (TF) value of four heavy metals were affected by the salinity, temperature, and dissolved oxygen. The highest BAF of each metal calculated was as follows: Cr (0.091 in winter) > Cu (0.054 in autumn) > Pb (0.016 in summer) > Zn (0.011 in summer). Highest root-rhizome TF values were recorded for four metals: 6.450 for Cu in autumn, 2.895 for Zn in summer, 7.031 for Pb in autumn, and 2.012 for Cr in autumn. This indicates that the P. australis AFW has potential to be used to protect the water of Qingcaosha Reservoir from heavy metal contamination. PMID:28717650

  15. Removal of Cu, Zn, Pb, and Cr from Yangtze Estuary Using the Phragmites australis Artificial Floating Wetlands

    Directory of Open Access Journals (Sweden)

    Xiaofeng Huang

    2017-01-01

    Full Text Available Contamination of heavy metals would threaten the water and soil resources; phytoremediation can be potentially used to remediate metal contaminated sites. We constructed the Phragmites australis artificial floating wetlands outside the Qingcaosha Reservoir in the Yangtze Estuary. Water characteristic variables were measured in situ by using YSI Professional Pro Meter. Four heavy metals (copper, zinc, lead, and chromium in both water and plant tissues were determined. Four heavy metals in estuary water were as follows: 0.03 mg/Kg, 0.016 mg/Kg, 0.0015 mg/Kg, and 0.004 mg/Kg. These heavy metals were largely retained in the belowground tissues of P. australis. The bioaccumulation (BAF and translation factor (TF value of four heavy metals were affected by the salinity, temperature, and dissolved oxygen. The highest BAF of each metal calculated was as follows: Cr (0.091 in winter > Cu (0.054 in autumn > Pb (0.016 in summer > Zn (0.011 in summer. Highest root-rhizome TF values were recorded for four metals: 6.450 for Cu in autumn, 2.895 for Zn in summer, 7.031 for Pb in autumn, and 2.012 for Cr in autumn. This indicates that the P. australis AFW has potential to be used to protect the water of Qingcaosha Reservoir from heavy metal contamination.

  16. Blanching resistant Cu-Cr coating by vacuum plasma spray

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, K.T. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.; Krotz, P.D. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.; Yuen, J.L. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.

    1995-11-01

    Copper alloy rocket engine combustion chamber linings have been found to deteriorate when exposed to cyclic reducing oxidizing (redox) environments, which are a consequence of the combustion process. The deterioration, known as blanching, can be characterized by increased roughness and burn-through sites in the wall of the combustion chamber lining and can seriously reduce the operational lifetime of the combustion chamber. A Cu-30 vol.%Cr coating produced by vacuum plasma spraying was effective in protecting the copper alloy substrate against blanching. The coating properties were characterized after cyclic oxidation exposure to 650 C in air followed by high pressure hydrogen charging. When exposed to an oxidizing environment at high temperatures, the coating formed a protective chromia scale that was substantially unreduced by high pressure hydrogen. (orig.)

  17. Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives.

    Science.gov (United States)

    Zhang, Tao; Wu, Ying-Xin; Huang, Xiong-Fei; Liu, Jun-Min; Xia, Bing; Zhang, Wei-Hua; Qiu, Rong-Liang

    2012-07-01

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C(6)HEDTA (2,2'-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C(12)HEDTA (2,2'-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C(6)HEDTA and C(12)HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C(6)HEDTA or C(12)HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C(6)HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C(12)HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C(12)HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid.

  18. Characterization and Activity of Cr,Cu and Ga Modified ZSM-5 for Direct Conversion of Methane to Liquid Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    Nor Aishah Saidina Amin; Didi Dwi Anggoro

    2003-01-01

    Direct conversion of methane using a metal-loaded ZSM-5 zeolite prepared via acidic ion exchange was investigated to elucidate the roles of metal and acidity in the formation of liquid hydrocarbons. ZSM-5 (SiO2/Al2O3=30) was loaded with different metals (Cr, Cu and Ga) according to the acidic ion-exchange method to produce metal-loaded ZSM-5 zeolite catalysts. XRD, NMR, FT-IR and N2 adsorption analyses indicated that Cr and Ga species managed to occupy the aluminum positions in the ZSM-5 framework. In addition, Cr species were deposited in the pores of the structure. However, Cu oxides were deposited on the surface and in the mesopores of the ZSM-5 zeolite. An acidity study using TPD-NH3, FT-IR, and IR-pyridine analyses revealed that the total number of acid sites and the strengths of the Bronsted and Lewis acid sites were significantly different after the acidic ion exchange treatment.Cu loaded HZSM-5 is a potential catalyst for direct conversion of methane to liquid hydrocarbons. The successful production of gasoline via the direct conversion of methane depends on the amount of aluminum in the zeolite framework and the strength of the Bronsted acid sites.

  19. The Effect of Diffusion Barrier and Bombardment on Adhesive Strength of CuCr Alloy Films

    Institute of Scientific and Technical Information of China (English)

    WANGJian-feng; SONGZhong-xiao; XUKe-wei; WANGYuan

    2004-01-01

    A novel co-sputtering method that combined magnetron sputtering (MS) with ion beam sputtering (IBS) was used to fabricate CuCr alloy films without breaking vacuum after depositing diffusion barrier with IBS. Different bombardment energies were used to improve the comprehensive properties of Cu alloy film. The results indicated that the effects of diffusion barriers and bombardment energy on adhesive strength could be evaluated by a rolling contact fatigue adhesion test. Diffusion barrier can enhance the adhesive strength, and the adhesion of CuCr/CrN was higher than that of CuCr/TiN. When bombarding energy was higher, the adhesive strength of CuCr/TiN films was higher due to the broader transition zone.

  20. Structure and flaws of CuCr alloys by explosive compaction

    Institute of Scientific and Technical Information of China (English)

    LI Jin-ping; MENG Song-he; HAN Jie-cai

    2005-01-01

    CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.

  1. Residual Stresses in Thermal Barrier Coatings for a Cu-8Cr-4Nb Substrate System

    Science.gov (United States)

    Ghosn, Louis J.; Raj, Sai V.

    2002-01-01

    Analytical calculations were conducted to determine the thermal stresses developed in a coated copper-based alloy, Cu-8%(at.%)Cr-4%Nb (designated as GRCop-84), after plasma spraying and during heat-up in a simulated rocket engine environment. Finite element analyses were conducted for two coating systems consisting of a metallic top coat, a pure copper bond coat and the GRCop-84. The through thickness temperature variations were determined as a function of coating thickness for two metallic coatings, a Ni-17%(wt%)Cr-6%Al-0.5%Y alloy and a Ni-50%(at.%)Al alloy. The residual stresses after low-pressure plasma spraying of the NiCrAlY and NiAl coatings on GRCop-84 substrate were also evaluated. These analyses took into consideration a 50.8 mm copper bond coat and the effects of an interface coating roughness. The through the thickness thermal stresses developed in coated liners were also calculated after 15 minutes of exposure in a rocket environment with and without an interfacial roughness.

  2. Protection of Advanced Copper Alloys With Lean Cu-Cr Coatings

    Science.gov (United States)

    Greenbauer-Seng, L. (Technical Monitor); Thomas-Ogbuji, L.

    2003-01-01

    Advanced copper alloys are used as liners of rocket thrusters and nozzle ramps to ensure dissipation of the high thermal load generated during launch, and Cr-lean coatings are preferred for the protection of these liners from the aggressive ambient environment. It is shown that adequate protection can be achieved with thin Cu-Cr coatings containing as little as 17 percent Cr.

  3. Simulations of Metal Cu in Heating Process

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Tao(张弢); WU, Ai-Ling(吴爱玲); GUAN, Li(管立); QI, Yuan-Hua(齐元华)

    2004-01-01

    Based on the Finnis-Sinsclair (FS) many-body potential model, the melting process of a system, which consists of 500 Cu atoms, controlled by period boundary condition has been simulated. The means of pair correlation function, mean square displacement and Honeycutt-Anderson bonded pair have been used to characterize the melting behavior of Cu at different heating rates. The simulation indicates that melting point of metal Cu is 1444 K during a continuous heating process, and the calculated diffusion constant at the melting point is 4.31×10-9 m2/s. These results are better than those from the EAM method, showing that the FS potential model works well in some disordered systems.

  4. Room-temperature ferromagnetism in Mn-doped CuCrO2 nanopowders

    Directory of Open Access Journals (Sweden)

    DENG Linyan

    2015-08-01

    Full Text Available (Cu1-xMnxCrO2 (0≤x≤6 at% and Cu(Cr1-yMnyO2 (0≤y≤6 at% nanopowders were prepared by combining solid-state reaction and ball milling.It is found that all the samples have a pure 3R-CuCrO2 delafossite structure.The lattice expansion supports the Mn entrance into the Cu and Cr sublattices,respectively,in (Cu1-xMnxCrO2 and Cu(Cr1-yMnyO2,which is further proved by X-ray photoelectron spectroscopy to some degree.Room-temperature ferromagnetism is achieved in B-site Mn-doped samples,originating from the hole-mediated Cr3+-Mn3+ double-exchange interaction.The saturation magnetization of this CuMO2 delafossite (M=Cr,Mn is about an order of magnitude higher than literature values,and gradually decreases with the Mn addition due to the combined influence of the number of the M-M pairs,the M-M distances and the hole density.

  5. LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Song, Rak-Hyun; Shin, Dong Ryul [Korea Institute of Energy Research, Taejon (Korea, Republic of); Dokiya, Masayuki [National Institute of Materials and Chemical Research, Ibaraki (Japan)

    1996-12-31

    In the planar SOFC, the interconnect materials plays two roles as an electrical connection and as a gas separation plate in a cell stack. The interconnect materials must be chemically stable in reducing and oxidizing environments, and have high electronic conductivity, high thermal conductivity, matching thermal expansion with an electrolyte, high mechanical strength, good fabricability, and gas tightness. Lanthanum chromite so far has been mainly used as interconnect materials in planar SOFC. However, the ceramic materials are very weak in mechanical strength and have poor machining property as compared with metal. Also the metallic materials have high electronic conductivity and high thermal conductivity. Recently some researchers have studied metallic interconnects such as Al{sub 2}O{sub 3}/Inconel 600 cermet, Ni-20Cr coated with (LaSr)CoO{sub 3}, and Y{sub 2}O{sub 3-} or La{sub 2}O{sub 3}-dispersed Cr alloy. These alloys have still some problems because Ni-based alloys have high thermal expansion, the added Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and La{sub 2}O{sub 3} to metals have no electronic conductivity, and the oxide formed on the surface of Cr alloy has high volatility. To solve these problems, in this study, LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC was investigated. The LaCrO{sub 3}-dispersed Cr can be one candidate of metallic interconnect because LaCrO{sub 3} possesses electronic conductivity and Cr metal has relatively low thermal expansion. The content of 25 vol.% LaCrO{sub 3} Was selected on the basis of a theoretically calculated thermal expansion. The thermal expansion, electrical and oxidation properties were examined and the results were discussed as related to SOFC requirements.

  6. The level and bioaccumulation of Cd, Cu, Cr and Zn in benthopelagic species from the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    SHI Ronggui; LIN Jing; YE Yi; MA Yifan; CAI Minggang

    2015-01-01

    The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms from this area. However, few data on trace metal concentrations are available for the benthopelagic organisms from the Bering Sea till now. Ten specimens of benthos (including 120 biological samples) were collected in the western Bering Sea in August 2008 during the 3rd Chinese National Arctic Research Expeditions, and the concentration of Cd, Cu, Cr and Zn determined using atomic absorption spectrometry. Zn, Cr and Cd concentrations in muscle tissues of the crab species were much higher than those from fish and cephalopod species, and the highest concentration of Cu was observed in the muscle tissues ofCylichna nucleoli. The results showed a similar hierarchy for Zn, Cr, Cd and Cu concentrations among different tissues as follows: hepatopancreas>muscle tissue>gonad. Bioconcentration factors indicated that benthic organisms had high accumulation abilities for Zn and Cu.

  7. Effect of heat treatments on precipitate microstructure and mechanical properties of a CuCrZr alloy

    DEFF Research Database (Denmark)

    Edwards, D.J.; Singh, Bachu Narain; Tähtinen, S.

    2007-01-01

    The precipitate microstructure of prime aged CuCrZr was coarsened by overaging to see if the larger precipitates could prevent the initiation of plastic flow localization in irradiated CuCrZr. A number of tensile and fracture toughness specimens of prime aged CuCrZr alloy were given overaging...

  8. Influence of Cerium and Yttrium on Cu-Cr-Zr Alloys

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Testing results shows that alloying with Ce and Y improves the hardness and softens temperature of cold worked Cu-Cr-Zr alloys obviously, while the conductivity was fluctuant with the variation of RE content. Observation and analysis indicate that micro-dosage RE elements helps to refine microstructure and morphology of Cu-Cr-Zr-RE alloys, suppress microstructure coarsening and improves homogeneous level of Cu-Cr-Zr alloys. Alloying with 0.01% Ce causes about 1% IACS increment of conductivity, and reduces about 2%~3.5% IACS conductivity after alloying with 0.03%~0.04% RE (Ce or Ce+Y) for Cu-Cr-Zr alloys. The microstructure of as-cast Cu-Cr-Zr alloy is refined after alloying with 0.01% Ce while the plasticity is improved slightly. Alloying with 0.01%~0.04% RE improves the softening temperature of deformed Cu-Cr-Zr alloys about 20~40 K; hardness is also improved about 20~35 HV. Test data indicate that alloying with Ce+Y raises softening temperature and hardness of Cu-Cr-Zr alloys more notably than alloying with pure Ce.

  9. A new Cu-8 Cr-4 Nb alloy for high temperature applications

    Science.gov (United States)

    Ellis, D. L.; Michal, G. M.; Dreshfield, R. L.

    1995-01-01

    Various applications exist where a high conductivity alloy with good strength and creep resistance are required. NASA LeRC has developed a Cu-8 at. percent Cr-4 at. percent Nb (Cu-8 Cr-4 Nb) alloy for these applications. The alloy is designed for use up to 700 C and shows exceptional strength, low cycle fatigue (LCF) resistance, and creep resistance. Cu-8 Cr-4 Nb also has a thermal conductivity of at least 72 percent that of pure Cu. Furthermore, the microstructure and mechanical properties of the alloy are very stable. In addition to the original application in combustion chambers, Cu-8 Cr-4 Nb shows promise for welding electrodes, brazing fixtures, and other applications requiring high conductivity and strength at elevated temperatures.

  10. Novel CuCr{sub 2}O{sub 4} embedded CuO nanocomposites for efficient photodegradation of organic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Mageshwari, K. [Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); PG & Research Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029, Tamilnadu (India); Sathyamoorthy, R., E-mail: rsathya59@gmail.com [PG & Research Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029, Tamilnadu (India); Lee, Jeong Yong [IBS, Center for Nanomaterials and Chemical Reactions, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Park, Jinsub, E-mail: jinsubpark@hanyang.ac.kr [Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-10-30

    Graphical abstract: - Highlights: • Novel CuO–CuCr{sub 2}O{sub 4} nanocomposites synthesized by reflux condensation method. • Methyl orange and methylene blue dye degradation studied under UV light irradiation. • Nanocomposites characterized by XRD, FESEM, TEM, EDX, UV–vis DRS and PL. • CuCr{sub 2}O{sub 4} loading effectively enhanced the catalytic activity of CuO. - Abstract: Novel photocatalyst based on CuO–CuCr{sub 2}O{sub 4} nanocomposites was synthesized for different Cr{sup 3+} concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr{sub 2}O{sub 4} as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr{sup 3+} in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO–CuCr{sub 2}O{sub 4} nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr{sub 2}O{sub 4} loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO–CuCr{sub 2}O{sub 4} nanocomposites can be attributed to the presence of CuCr{sub 2}O{sub 4} as an electron acceptor, which improves the effective charge separation in CuO.

  11. Translocation and accumulation of Cr, Hg, As, Pb, Cu and Ni by Amaranthus dubius (Amaranthaceae) from contaminated sites.

    Science.gov (United States)

    Mellem, John J; Baijnath, Himansu; Odhav, Bharti

    2009-05-01

    Phytoremediation is an emerging technology where specially selected and engineered metal-accumulating plants are used for bioremediation. This study was undertaken to evaluate the potential of Amaranthus dubius for phytoremediation of chromium (Cr), mercury (Hg), arsenic (As), lead (Pb), copper (Cu) and nickel (Ni). Locally gathered soil and plants of A. dubius were investigated for the metals from a regularly cultivated area, a landfill site and a waste water treatment site. Metals were extracted from the samples using microwave-digestion and analyzed using Inductively Coupled Plasma-Mass Spectroscopy. The mode of phytoremediation, effect of the metals on the plants, ability of the plant to extract metals from soil (Bioconcentration Factor) and the ability of the plants to move the metals to the aerial parts of the plants (Translocation Factor) were evaluated. The survey of the three sites showed that soils were heavily contaminated with Cr, Hg, Cu and Ni. These levels were far above acceptable standards set for soils and above the standards set for the Recommended Dietary Allowance. Specimens of A. dubius from the three sites showed that they could tolerate Hg, sequester it from the soil, and translocate it to the shoots. Cr could only be removed from the soil and stored in the roots, with limited amounts translocated to the aerial parts. Pb, As, Ni, and Cu have some degree of transportability from the soil to the roots but not to aerial parts. The ability of A. dubius to be considered for phytoremediation has to be viewed with caution because translocation of the metals to the aerial parts of the plant is limited.

  12. Novel Preparation of Nano-Composite CuO-Cr2O3 Using Ctab-Template Method and Efficient for Hydrogenation of Biomass-Derived Furfural

    Science.gov (United States)

    Yan, Kai; Wu, Xu; An, Xia; Xie, Xianmei

    2013-02-01

    A simple route to fabricate nano-composite oxides CuO-Cr2O3 using hexadecyltrimethylammonium bromide (CTAB)-templated Cu-Cr hydrotalcite as the precursor is presented. This novel method is based on CTAB-templating effect for mesostructure directing and using the cheap metal nitrate, followed by removal of CTAB. It was indicated that the nano-composite CuO-Cr2O3 was formed during the removal of CTAB. X-ray diffraction (XRD) and transitional electronic microscopy (TEM) revealed nice nano-composite oxides CuO-Cr2O3 were formed with high crystallinity. N2 adsorption and desorption indicated that a high surface area of 170.5 m2/g with a pore size of 2.7 nm of the nano-composite CuO-Cr2O3 was facilely resulted. The as-synthesized nano-composite oxides CuO-Cr2O3 display good catalytic activities for hydrogenation of furfural to furfuryl alcohol, whereas 86% selectivity was achieved at 75% conversion of furfural.

  13. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17 Percent Cr and Cu-17 Percent Cr-5 Percent Al Part II: Scale Microstructures

    Science.gov (United States)

    Raj, Sai V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. Details of the oxidation kinetics of these alloys were discussed in Part I. This paper analyzes the microstructures of the scale and its composition in an attempt to elucidate the oxidation mechanisms in these alloys. The scales formed on Cu-17%Cr specimens oxidized between 773 and 973 K consisted of external CuO and subsurface Cu2O layers. The total thickness of these scales varied from about 10 m at 773 K to about 450 m at 973 K. In contrast, thin scales formed on Cu-17%Cr-5%Al alloys oxidized between 773 and 1173 K. The exact nature of these scales could not be determined by x-ray diffraction but energy dispersive spectroscopy analyses were used to construct a scale composition map. Phenomenological oxidation mechanisms are proposed for the two alloys.

  14. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17 Percent Cr and Cu-17 Percent Cr-5 Percent Al. Part 2; Scale Microstructures

    Science.gov (United States)

    Raj, S. V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. Details of the oxidation kinetics of these alloys were discussed in Part I. This paper analyzes the microstructures of the scale and its composition in an attempt to elucidate the oxidation mechanisms in these alloys. The scales formed on Cu-17%Cr specimens oxidized between 773 and 973 K consisted of external CuO and subsurface Cu2O layers. The total thickness of these scales varied from about 10 m at 773 K to about 450 m at 973 K. In contrast, thin scales formed on Cu-17%Cr-5%Al alloys oxidized between 773 and 1173 K. The exact nature of these scales could not be determined by x-ray diffraction but energy dispersive spectroscopy analyses were used to construct a scale composition map. Phenomenological oxidation mechanisms are proposed for the two alloys.

  15. Lifting of the Au(100) surface reconstruction by Pt, Cr, Fe, and Cu adsorption

    Science.gov (United States)

    Tempas, Christopher D.; Skomski, Daniel; Tait, Steven L.

    2016-12-01

    The adsorption and growth of metals on the surfaces of other metals is an important topic for studies of heterogeneous catalysis and bimetallic nanoparticles. The surface structure of these systems impacts nanoparticle growth, catalytic activity, and reaction selectivity. In these experiments, platinum, chromium, iron, or copper were vapor deposited on the reconstructed Au(100) surface. The initial growth of each metal was studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Each of the four metals forms anisotropic rectangular islands oriented in the direction of the gold reconstruction rows. The gradual lifting of the surface reconstruction by increased metal coverage is observed, and the reconstruction is fully lifted after 0.5 ML of Pt, Cr, or Fe, or by 3.3 ML of Cu. After the reconstruction is lifted, the island shape changes from rectangular to square, illustrating the effect of surface structure on growth. Second layer islands begin to form before the completion of the first full layer.

  16. Utilização de pelos de animais silvestres para monitoramento ambiental de Cd, Cr, Cu, Fe, Mn, Pb e Zn Utilization of wild animal hair for the environmental monitoring of Cd, Cr, Cu, Fe, Mn, Pb e Zn

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Hoff Brait

    2009-01-01

    Full Text Available This study investigates the use of wild animal hair of C. brachyurus, C. thous and L. pardalis as biomonitors of trace metal at Parque Nacional das Emas, Brazil. Results reveal a strong correlation between Cd and Pb as well as Cu and Zn, which suggests a single source of emission. Most metals showed a lower or equal concentration than those obtained in previous studies. The research shows that monitoring may be performed only with Zn, Pb, Cd, and Cr because of statistical similarity and of a non-natural occurrence of large amounts of the material under analysis.

  17. Defect properties of CuCrO2: A density functional theory calculation

    Institute of Scientific and Technical Information of China (English)

    Fang Zhi-Jie; Zhu Ji-Zhen; Zhou Jiang; Mo Man

    2012-01-01

    Using the first-principles methods,we study the formation energetics properties of intrinsic defects,and the charge doping properties of extrinsic defects in transparent conducting oxides CuCrO2.Intrinsic defects,some typical acceptortype,and donor-type extrinsic defects in their relevant charge state are considered.By systematically calculating the formation energies and transition energy,the results of calculation show that,Vcu,Oi,and OCu are the relevant intrinsic defects in CuCrO2; among these intrinsic defects,VCu is the most efficient acceptor in CuCrO2.It is found that all the donor-type extrinsic defects have difficulty in inducing n-conductivity in CuCrO2 because of their deep transition energy level.For all the acceptor-type extrinsic defects,substituting Mg for Cr is the most prominent doping acceptor with relative shallow transition energy levels in CuCrO2.Our calculation results are expected to be a guide for preparing promising n-type and p-type materials in CuCrO2.

  18. Accumulation of Cr, Cd, Pb, Cu, and Zn by plants in tanning sludge storage sites: opportunities for contamination bioindication and phytoremediation.

    Science.gov (United States)

    Yuan, Yongqiang; Yu, Shen; Bañuelos, G S; He, Yunfeng

    2016-11-01

    Tanning sludge enriched with high concentrations of Cr and other metals has adverse effects on the environment. Plants growing in the metalliferous soils may have the ability to cope with high metal concentrations. This study focuses on potentials of using native plants for bioindication and/or phytoremediation of Cr-contaminated sites. In the study, we characterized plants and soils from six tanning sludge storage sites. Soil in these sites exhibited toxic levels of Cr (averaged 16,492 mg kg(-1)) and other metals (e.g., 48.3 mg Cu kg(-1), 2370 mg Zn kg(-1), 44.9 mg Pb kg(-1), and 0.59 mg Cd kg(-1)). Different metal tolerance and accumulation patterns were observed among the sampled plant species. Phragmites australis, Zephyranthes candida, Cynodon dactylon, and Alternanthera philoxeroides accumulated moderate-high concentrations of Cr and other metals, which could make them good bioindicators of heavy metal pollution. High Cr and other metal concentrations (e.g., Cd and Pb) were found in Chenopodium rubrum (372 mg Cr kg(-1)), Aster subulatus (310 mg Cr kg(-1)), and Brassica chinensis (300 mg Cr kg(-1)), being considered as metal accumulators. In addition, Nerium indicum and Z. candida were able to tolerate high concentrations of Cr and other metals, and they may be used as preferable pioneer species to grow or use for restoration in Cr-contaminated sites. This study can be useful for establishing guidelines to select the most suitable plant species to revegetate and remediate metals in tanning sludge-contaminated fields.

  19. A DFT Study on the Structure and Properties of Cu/Cr2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    张敏华; 李如珍; 余英哲

    2012-01-01

    Using DFT method, the stable adsorption configurations of Cu4 cluster on Cr2O3 (0001) surface were investi- gated. The regular tetrahedron structure and the planar structures were considered as the initial adsorption configu- ration of Cu4 cluster, respectively. The adsorption energies of the two structures were also calculated. The simulation result indicated that the adsorption energy of the regular tetrahedron structure was higher than that of the planar structure, and thus the regular tetrahedron structure was confirmed to be the stable adsorption configuration for Cu4 cluster on Cr2O3 (0001) surface. Moreover, it was observed that the Cu4 cluster showed the definite stable adsorption sites on Cr2O3 (0001) surface, namely 3-fold O sites. During the adsorption process of Cu4 cluster onto Cr2O3 (0001) surface, the Cu4 cluster could bond with more Cr or O atoms on the surface, and the apparent charge transfer also occurred correspondingly. Meanwhile, the Cu4 cluster and Cr2O3 (0001) surface would bond in the form of local polarization to enhance the stability of adsorption configuration.

  20. 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.

  1. High field magnetotransport and point contact Andreev reflection measurements on CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}Br—Degenerate magnetic semiconductor single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, K., E-mail: borisovk@tcd.ie; Coey, J. M. D.; Stamenov, P. [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland); Alaria, J. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom)

    2014-05-07

    Single crystals of the metallically degenerate fully magnetic semiconductors CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}Br have been prepared by the Chemical Vapour Transport method, using either Se or Br as transport agents. The high-quality, millimetre-sized, octahedrally faceted, needle- and platelet-shaped crystals are characterised by means of high field magnetotransport (μ{sub 0}H≤ 14 T) and Point Contact Andreev Reflection. The relatively high spin polarisation observed |P|>0.56, together with the relatively low minority carrier effective mass of 0.25 m{sub e}, and long scattering time  10{sup −13} s, could poise these materials for integration in low- and close-to-room temperature minority injection bipolar heterojunction transistor demonstrations.

  2. S, Zn, Cr, Cu and Fe changes during fluvial sediments oxidation Transformaciones del S, Zn, Cr, Cu y Fe en sedimentos fluviales durante el proceso de secado

    Directory of Open Access Journals (Sweden)

    María Pía Di Nanno

    2009-12-01

    Full Text Available Acidification of dredged sediments which have been disposed on land is highly dependent on redox shifts. The aim of the present work was to assess changes in sulphur, metal speciation (Zn, Fe, Cr y Cu and acidity caused by a polluted sediment oxidation event. Sediments were dessicated under controlled conditions and sulphide compounds (acid volatile sulphides-AVS- and sulphate, pH and neutralization potential were measured through time during 36 days. Zinc, Cu, Cr and Fe speciation (BCR metal sequential extraction procedure were measured at the beginning of the experiment and at day 22. An acid-base equilibrium method based on the BCR procedure was employed to assess the sediment acidification risk. Some of the re-suspension experiments were inoculated with an Acidithiobacillus ferrooxidans strain to assess biological catalysis on sulphide oxidation. Acid-base equilibrium results indicated the sediment sample had a significant acidification potential. Oxidation increased sulphate levels (56 to 2300 mg S kg-¹ in the desiccation experiment with a temporal evolution adjusted by a logistic model, and a 2100 to 3000 mg SO4 -² L-¹ increase for the resuspension experiments. Sulphide oxidation rates varied between 0 to 3.1.10-9 mg O2 kg-¹ s-¹ for the drying sediment. Zinc changes could be explained partially by ZnS conversion to ZnSO4 during oxidation. Iron reduction could be attributed to an increase in Fe oxides crystallinity. Acid-base equilibrium for the sample indicated it was a potentially acid-generating material. Zinc increased its bioavailability during drying and was the only metal that appeared in significant amounts in solution during re-suspension. Land-filling with dredged sediments could present increased metals bioavailability problems despite having an important and effective neutralization potential.La evaluación de los riesgos de acidificación por deposición de sedimentos dragados en superficie es muy dependiente de los

  3. Effect of alloying elements on mechanical properties in Cu-15%Cr in-situ composites

    Institute of Scientific and Technical Information of China (English)

    H. G. Suzukit; J. Ma; K. Mihara; S. Sakai; S. Sun

    2004-01-01

    The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15 %Cr(mass fraction) in-situ composites were systematically studied and high strength and high electrical conductive Cu base in-situ composites have been developed. The best combination is the addition of 0.1% to 0.2% Zr, Ti, or Sn in Cu 15 %Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of the second phase, and the fine Cr precipitates. The aging treatment to reduce solute atoms has a beneficial effect on the increase of electrical conductivity. The addition of Zr, or Ti of about 0.15% to 0.2% promotes the precipitation of Cr particles.

  4. Cyclic Oxidation Behavior of CuCrAl Cold-Sprayed Coatings for Reusable Launch Vehicles

    Science.gov (United States)

    Raj, Sai; Karthikeyan, J.

    2009-01-01

    The next generation of reusable launch vehicles is likely to use GRCop-84 [Cu-8(at.%)Cr-4%Nb] copper alloy combustion liners. The application of protective coatings on GRCop-84 liners can minimize or eliminate many of the environmental problems experienced by uncoated liners and significantly extend their operational lives and lower operational cost. A newly developed Cu- 23 (wt.%) Cr-5% Al (CuCrAl) coating, shown to resist hydrogen attack and oxidation in an as-cast form, is currently being considered as a protective coating for GRCop-84. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique, where the CuCrAl was procured as gas-atomized powders. Cyclic oxidation tests were conducted between 773 and 1,073 K to characterize the coated substrates.

  5. Binary Cu-Zr Bulk Metallic Glasses

    Institute of Scientific and Technical Information of China (English)

    TANG Mei-Bo; ZHAO De-Qian; PAN Ming-Xiang; WANG Wei-Hua

    2004-01-01

    @@ We report that bulk metallic glasses (BMGs) can be produced up to 2 mm by a copper mould casting in Cux Zr1-x binary alloy with a wide glass forming composition range (45 < x < 60 at.%). We find that the formation mechanism for the binary Cu-Zr binary BMG-forming alloy is obviously different from that of the intensively studied multicomponent BMGs. Our results demonstrate that the criteria for the multicomponent alloys with composition near deep eutectic and strong liquid behaviour are no longer the major concern for designing BMGs.

  6. Purification of Organic Wastewater Containing Cu2+ and Cr3+ by a Combined Process of Micro Electrolysis and Biofilm

    Institute of Scientific and Technical Information of China (English)

    李天成; 姜斌; 冯霞; 王大为; 袁绍军; 李鑫钢

    2003-01-01

    A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Cr3+,and the relevant purifying mechanism was also addressed. In detail,organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes,However,for heavy metal ions (Cu2+,Cr3+),part was removed by electrodeposition,and some was adorbed on biofilm.In order to compare with the combined process of micro electrolysis and biofilm,the experimental data of micro electrolysis process (intermittent )or biofilm process (continuous)were provided,and the kinetic data of C6H12O6(glucose)biodegradation by cultured microbes or acclimated microbes were also obtained,These experimental results indicated that for wastewater initially consisted of C6H12O6(500 mg.L-1),Cu2+ and Cr3+(10mg.L6-1),after treatment,its concentrations of C6H12O6,Cu2+ and Cr3+ were lowered to the leve of 55-65 mg.L-1),after treatment,its concentrations of C6H12O6,Cu2+ and Cr3+ were lowered to the level of 55-65 mg.L-1,and less than 1mg.L-1,respectively,And the industrial reused water standards could be met by treated wastewater.

  7. Properties and features of structure formation CuCr-contact alloys in electron beam cladding

    Energy Technology Data Exchange (ETDEWEB)

    Durakov, Vasiliy G., E-mail: electron@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Dampilon, Bair V., E-mail: dampilon@ispms.tsc.ru, E-mail: gnusov@rambler.ru; Gnyusov, Sergey F., E-mail: dampilon@ispms.tsc.ru, E-mail: gnusov@rambler.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    The microstructure and properties of the contact CuCr alloy produced by electron-beam cladding have been investigated. The effect of the electron beam cladding parameters and preheating temperature of the base metal on the structure and the properties of the coatings has been determined. The bimodal structure of the cladding coating has been established. The short circuit currents tests have been carried out according to the Weil-Dobke synthetic circuit simulating procedure developed for vacuum circuit breakers (VCB) test in real electric circuits. Test results have shown that the electron beam cladding (EBC) contact material has better breaking capacity than that of commercially fabricated sintered contact material. The application of the technology of electron beam cladding for production of contact material would significantly improve specific characteristics and reliability of vacuum switching equipment.

  8. Investigation into nanoscratching mechanical response of AlCrCuFeNi high-entropy alloys using atomic simulations

    Science.gov (United States)

    Wang, Zining; Li, Jia; Fang, QiHong; Liu, Bin; Zhang, Liangchi

    2017-09-01

    The mechanical behaviors and deformation mechanisms of scratched AlCrCuFeNi high entropy alloys (HEAs) have been studied by molecular dynamics (MD) simulations, in terms of the scratching forces, atomic strain, atomic displacement, microstructural evolution and dislocation density. The results show that the larger tangential and normal forces and higher friction coefficient take place in AlCrCuFeNi HEA due to its outstanding strength and hardness, and high adhesion and fracture toughness over the pure metal materials. Moreover, the stacking fault energy (SFE) in HEA increases the probability to initiate dislocation and twinning, which is conducive to the formation of complex deformation modes. Compared to the single element metal workpieces, the segregation potency of solutes into twinning boundary (TB) is raised due to the decreasing segregation energy of TB, resulting in the stronger solute effects on improving twinning properties for HEA workpiece. The higher dislocation density and the more activated slipping planes lead to the outstanding plasticity of AlCrCuFeNi HEA. The solute atoms as barriers to hinder the motion of dislocation and the severe lattice distortion to suppress the free slipping of dislocation are significantly stronger obstacles to strengthen HEA. The excellent comprehensive scratching properties of the bulk AlCrCuFeNi HEAs are associated with the combined effects of multiple strengthening mechanisms, such as dislocation strengthening, deformation twinning strengthening as well as solute strengthening. This work provides a basis for further understanding and tailoring SFE in mechanical properties and deformation mechanism of HEAs, which maybe facilitate the design and preparation of new HEAs with high performance.

  9. Investigation of vacuum properties of CuCrZr alloy for high-heat-load absorber

    Science.gov (United States)

    Shueh, C.; Chan, C. K.; Chang, C. C.; Sheng, I. C.

    2017-01-01

    The Taiwan Photon Source (TPS) uses high-heat-load (HHL) absorbers to protect downstream ultrahigh-vacuum chambers from overheating. In this work, we propose to use the CuCrZr alloy (ASTM C18150) for the HHL absorber body and the ConFlat flanges. We use the throughput method to measure the thermal outgassing rate and a helium leak detector to verify the vacuum seal between the CuCrZr alloy and stainless-steel flanges. The measured outgassing rate of the CuCrZr alloy was 5.8×10-10 Pa m/s after 72 h of pumping and decreased to 2.0 × 10-10 Pa m/s after 100 h of pumping. The leak rate through the vacuum seal between a CuCrZr flange and a stainless-steel flange was less than 1 × 10-10 Pa m3/s even after mounting and unmounting the flanges ten times and baking them at 250 °C. These results indicate that CuCrZr alloy is suitable for integrating HHL components with ConFlat CuCrZr flanges for the absorption of the synchrotron radiation generated by the TPS.

  10. Theoretical prediction of half metallic ferromagnetic full-Heusler alloys Cs2CrGe

    Science.gov (United States)

    Cherid, S.; Benstaali, W.; Abbad, A.; Bentata, S.; Lantri, T.; Abbar, B.

    2017-07-01

    The structural, electronic and elastic properties of full-Heusler alloys Cs2CrGe are examined in this study using FP-LAPW method based on density functional theory. Results of our calculations predict that the Hg2CuTi-type structure is more stable than the Cu2MnAl-type structure and that the ground state of this alloy is ferromagnetic. The band structure of Cs2CrGe shows half metallic behavior for the two approaches GGA and mBJ-GGA with an indirect band gap. The total magnetic moment calculated is in good agreement with the Slater-Pauling rule for full-Heusler alloys with an important magnetic moment equal to 4 μB. Elastic properties indicate that our compound is ductile, anisotropic and not too rigid.

  11. Characterization of transparent superconductivity Fe-doped CuCrO2 delafossite oxide

    Science.gov (United States)

    Taddee, Chutirat; Kamwanna, Teerasak; Amornkitbamrung, Vittaya

    2016-09-01

    Delafossite CuCr1-xFexO2 (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 CuCr1-xFexO2 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 CuCrO2 samples exhibited ferromagnetic behavior at room temperature. This indicated that the substitution of Fe3+ for Cr3+ produced a mixed effect on the magnetic properties of CuCrO2 delafossite oxide. The temperature dependent resistivity measurements clearly revealed the presence of superconductivity in the CuCr1-xFexO2 with a superconducting transition up to 118 K.

  12. Design of Cu8Zr5-based bulk metallic glasses

    Science.gov (United States)

    Yang, L.; Xia, J. H.; Wang, Q.; Dong, C.; Chen, L. Y.; Ou, X.; Liu, J. F.; Jiang, J. Z.; Klementiev, K.; Saksl, K.; Franz, H.; Schneider, J. R.; Gerward, L.

    2006-06-01

    Basic polyhedral clusters have been derived from intermetallic compounds at near-eutectic composition by considering a dense packing and random arrangement of atoms at shell sites. Using such building units, bulk metallic glasses can be formed. This strategy was verified in the Cu-Zr binary system, where we have demonstrated the existence of Cu8Zr5 icosahedral clusters in Cu61.8Zr38.2, Cu64Zr36, and Cu64.5Zr35.5 amorphous alloys. Furthermore, ternary bulk metallic glasses can be developed by doping the basic Cu-Zr alloy with a minority element. This hypothesis was confirmed in systems (Cu0.618Zr0.382)100-xNbx, where x =1.5 and 2.5at.%, and (Cu0.618Zr0.382)98Sn2. The present results may open a route to prepare amorphous alloys with improved glass forming ability.

  13. Local atomic structure investigation of AlFeCuCrMgx (0.5, 1, 1.7) high entropy alloys: X-ray absorption spectroscopy study

    Science.gov (United States)

    Maulik, Ornov; Patra, N.; Bhattacharyya, D.; Jha, S. N.; Kumar, Vinod

    2017-02-01

    The present paper reports local atomic structure investigation of novel AlFeCuCrMgx (x=0.5, 1, 1.7) high entropy alloys (HEAs) produced by mechanical alloying using Fe, Cr and Cu K-edge X-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopy. XANES spectra measured at Fe and Cr K-edges resemble that of the respective pure metal foils, while the spectrum measured at Cu K-edge manifests the presence of some other phases in the as-milled alloys. The radial distribution functions (RDFs) obtained from Fourier transformation of EXAFS spectra support the formation of disordered BCC structure.

  14. Magnetic and Structural Properties in Co/Cu/Co Sandwiches with Ni and Cr Buffer Layers

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The magnetic and structural properties in Co/Cu/Co sandwiches with Ni and Cr buffer layers were investigated. It was found that the coercivity in Ni layer buffered samples decreases with increasing Ni layer thickness, while that in Cr layer buffered ones increases with increasing Cr layer thickness, leading to a large difference in field sensitivity of their giant magnetoresistance (GMR) properties. X-ray diffraction and high resolution transmission electron microscope images exhibited that there is a strong fcc (111) texture in the samples with Ni buffer layer. But there are only randomly oriented polycrystalline grains in Cr buffered sandwiches. According to atomic force microscope topography, the surface roughness of Cr buffered sandwiches is smaller than that of Ni buffered ones. It is demonstrated that buffer layer influences both magnetic and structural properties in Co/Cu/Co sandwiches as well as their GMR characteristics.

  15. Statistical Analysis of Main and Interaction Effects on Cu(II) and Cr(VI) Decontamination by Nitrogen-Doped Magnetic Graphene Oxide

    Science.gov (United States)

    Hu, Xinjiang; Wang, Hui; Liu, Yunguo

    2016-10-01

    A nitrogen-doped magnetic graphene oxide (NMGO) was synthesized and applied as an adsorbent to remove Cu(II) and Cr(VI) ions from aqueous solutions. The individual and combined effects of various factors (A: pH, B: temperature, C: initial concentration of metal ions, D: CaCl2, and E: humic acid [HA]) on the adsorption were analyzed by a 25-1 fractional factorial design (FFD). The results from this study indicated that the NMGO had higher adsorption capacities for Cu(II) ions than for Cr(VI) ions under most conditions, and the five selected variables affected the two adsorption processes to different extents. A, AC, and C were the very important factors and interactions for Cu(II) adsorption. For Cr(VI) adsorption, A, B, C, AB, and BC were found to be very important influencing variables. The solution pH (A) was the most important influencing factor for removal of both the ions. The main effects of A-E on the removal of Cu(II) were positive. For Cr(VI) adsorption, the main effects of A and D were negative, while B, C, and E were observed to have positive effects. The maximum adsorption capacities for Cu(II) and Cr(VI) ions over NMGO were 146.365 and 72.978 mg/g, respectively, under optimal process conditions.

  16. Statistical Analysis of Main and Interaction Effects on Cu(II) and Cr(VI) Decontamination by Nitrogen–Doped Magnetic Graphene Oxide

    Science.gov (United States)

    Hu, Xinjiang; Wang, Hui; Liu, Yunguo

    2016-01-01

    A nitrogen–doped magnetic graphene oxide (NMGO) was synthesized and applied as an adsorbent to remove Cu(II) and Cr(VI) ions from aqueous solutions. The individual and combined effects of various factors (A: pH, B: temperature, C: initial concentration of metal ions, D: CaCl2, and E: humic acid [HA]) on the adsorption were analyzed by a 25−1 fractional factorial design (FFD). The results from this study indicated that the NMGO had higher adsorption capacities for Cu(II) ions than for Cr(VI) ions under most conditions, and the five selected variables affected the two adsorption processes to different extents. A, AC, and C were the very important factors and interactions for Cu(II) adsorption. For Cr(VI) adsorption, A, B, C, AB, and BC were found to be very important influencing variables. The solution pH (A) was the most important influencing factor for removal of both the ions. The main effects of A–E on the removal of Cu(II) were positive. For Cr(VI) adsorption, the main effects of A and D were negative, while B, C, and E were observed to have positive effects. The maximum adsorption capacities for Cu(II) and Cr(VI) ions over NMGO were 146.365 and 72.978 mg/g, respectively, under optimal process conditions. PMID:27694891

  17. Cr isotope fractionation in metal-mineral-microbe interactions

    Science.gov (United States)

    Zhang, Qiong; Porcelli, Don; Thompson, Ian; Amor, Ken; Galer, Stephen

    2016-04-01

    Microbes interact with metals and minerals in the environments, altering their physical and chemical state whilst in turn the metals and minerals affect microbial growth, activity and survival. The interactions between Cr, Fe minerals and bacteria were investigated in this study. Cr(VI) reduction experiments by two iron-reducing bacteria, Pseudomonas fluorescens LB 300 and Shewanella oneidensis MR 1, in the presence of two iron oxide minerals, goethite and hematite, were conducted. Both minerals were found to inhibit the Cr(VI) reduction rate by Pseudomonas fluorescens LB 300 but accelerated Shewanella oneidensis MR 1. The Cr isotopic fractionation factor generated by both bacteria was mostly independent of the presence of the minerals, except for hematite with Pseudomonas fluorescens LB 300, where the ɛ was much higher. Aqueous Fe(III) in the solution did not have any detectable impact on either bacterial Cr reduction rates or the isotopic fractionation factors, indicating that the reduction of Cr(VI) occurred prior to that of Fe(III). The presence of aqueous Fe(II) induced a very fast abiotic reduction of Cr, but had little impact on the bacterial Cr reduction rates or its isotope fractionations. The evidence suggests that the different impact that Fe minerals had on the bacteria were related to the way they attached to the minerals and the difference in the reduction mechanism. SEM images confirmed that the attachment of Pseudomonas fluorescens LB 300 on the mineral surfaces were much more tightly packed than that of Shewanella oneidensis MR 1, so reducing mineral-metal interactions.

  18. Precipitation sequence of Cu-Cr-Zr-Mg alloy during early aging stage%Cu-Cr-Zr-Mg合金早期时效析出贯序

    Institute of Scientific and Technical Information of China (English)

    余方新; 程建奕; 沈斌

    2013-01-01

    The precipitation process in Cu-0.69Cr-0.10Zr-0.02Mg alloy during the early aging stage at 450 ℃ was investigated by transmission electron microscopy and high resolution transmission electron microscopy. The precipitation sequence in the Cu-Cr-Zr-Mg alloy aged at 450 ℃ is supersaturated solid solution→solution segregation→GP zone (Ⅰ) (FCC Cr-rich phase)→GP zone (Ⅱ) (ordered FCC Cr-rich phase)→ordered BCC Cr-rich phase. In the evolution of decomposition, the interface between the precipitates and the Cu matrix changes from the full coherent one to the coherent-partial coherent one, and the orientation relationship changes from the cube-on-cube to Nishiyama-Wassermann. The coherent interface between the FCC Cr-rich precipitates and Cu matrix facilitates the formation of the FCC precipitates. The ordering of Cr-rich precipitates accelerates the precipitation process, which facilitates the formation of the BCC precipitates and promotes the development of Nishiyama-Wassermann orientation relationship.%通过透射电镜和高分辨透射电镜研究 Cu-0.69Cr-0.10Zr-0.02Mg 合金在450℃早期时效的析出贯序。研究表明:合金在450℃早期时效的析出贯序为过饱和固溶体→溶质偏聚→FCC富Cr的GP区(Ⅰ)→FCC有序富Cr的GP区(Ⅱ)→BCC有序富Cr相。在脱溶演变过程中,析出相和基体之间的界面由完全共格界面向共格-半共格界面转变,位向关系由立方-立方向Nishiyama-Wassermann位向关系转变。共格界面的形成有利于FCC富Cr相的形成。富Cr析出相的有序化加速析出进程,并有利于BCC相的形成,促进了Nishiyama-Wassermann位向关系的发展。

  19. Optical and Dielectric Properties of Cr3+ & Cu2+ :P2O5-ZnO-LiF Glasses

    Directory of Open Access Journals (Sweden)

    C. Parthasaradhi Reddy

    2014-04-01

    Full Text Available The present paper reports on the results concerning structural, thermal, optical (absorption & emission, dielectric and ac conductivity properties of host glass in the chemical composition of 50P2O5-30ZnO-20LiF (PZL, and two different transition metal ions doped glasses such as (0.5 mol% Cr3+:49.5P2O5-30ZnO-20LiF and (0.5 mol% Cu2+:49.5P2O5-30ZnO-20LiF glasses have successfully been prepared by a melt quenching technique. Thermal analysis has been carried out on the host (PZL precursor chemical mix in evaluating weight loss from its TG profile and glass transition temperature (Tg and crystalline temperature (Tc from its DTA profile. The presence of Cr3+ and Cu2+ has been confirmed from their EDX profiles and absorption spectra. From the absorption spectrum of Cr3+: PZL glass, a couple of bands at 460 nm (4A2g (F  4T1g (F and 664 nm ( 4A2g (F  4T2g (F have been displayed where as a broad absorption band at 824 nm (2B1g → 2B2g is observed from Cu2+: PZL optical glass. The nature of local symmetry and structural information of the neighboring atoms of dopant ions (Cr3+& Cu2+ in the host matrix have been understood by evaluating the crystal field strength (Dq and Racah (B & C parameters

  20. A triple action chemosensor for Cu(2+) by chromogenic, Cr(3+) by fluorogenic and CN(-) by relay recognition methods with bio-imaging of HeLa cells.

    Science.gov (United States)

    Vijay, Natarajan; Balamurugan, Gopal; Venkatesan, Parthiban; Wu, Shu Pao; Velmathi, Sivan

    2017-09-13

    A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu(2+) and Cr(3+) ions with significant changes in UV-Vis absorbance and fluorescence intensity. The results showed that Cr(3+) induced greater fluorescence enhancement whereas Cu(2+) ions bound strongly with the receptor by showing a strong absorption band at 554 nm but with weak fluorescence. A visible colour change was observed by the addition of Cu(2+) and that colour change is due to the opening of the spirolactam ring triggered by the addition of Cu(2+) ions. Job's plot analysis indicated a 1 : 2 and 1 : 1 binding stoichiometry between the chemosensor and Cr(3+)/Cu(2+). Subsequently, the R1 - Cu(2+) complex chemosensor was employed to detect CN(-) in the presence of different anions, such as F(-), Cl(-), Br(-), I(-), AcO(-), H2PO4(-), HSO4(-), NO3(-) and (-)OH. In addition, the live cell imaging of HeLa cells using R1 and Cr(3+) was demonstrated successfully.

  1. Microstructure and corrosion resistance of AlCrFeCuCo high entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xing-Wu, E-mail: qiuxingwu@126.com [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China); Zhang, Yun-Peng; He, Li [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Liu, Chun-ge [Department of Transportation and Municipal Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China)

    2013-02-05

    Highlights: Black-Right-Pointing-Pointer We use a new method (laser cladding) to prepare high-entropy alloy. Black-Right-Pointing-Pointer We gained small microstructure under rapid solidification condition. Black-Right-Pointing-Pointer We studied corrosion resistance of AlCrFeCuCo high-entropy alloy in two different liquids. - Abstract: The AlCrFeCuCo high-entropy alloys were prepared by the laser cladding method. The microstructure and corrosion resistance property of AlCrFeCuCo high-entropy alloy were researched by scanning electron microscopy, X-ray diffraction and electrochemical workstation. The results show that, under the rapid solidification small microstructure gained, the morphology of AlCrFeCuCo high entropy alloy is simple, the phase mainly compose of FCC and BCC; elements segregated in the alloys; the alloy shows excellent corrosion resistance, along with the increase of the scanning speed, alloy corrosion resistance performance shows a enhancement in the first and then weakened trend. The corrosion resistance performance of AlCrFeCuCo high-entropy alloys in 1 mol/L NaCl solution is better than in 0.5 mol/L H{sub 2}SO{sub 4} solution.

  2. Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, Hiroshi, E-mail: nishi.hiroshi88@jaea.go.jp [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan); Enoeda, Mikio [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan)

    2011-10-01

    In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 deg. C. Grain growth occurred on 1045 deg. C HIP CuCrZr, though slightly on 980 deg. C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 deg. C. The low cycle fatigue strength of 1045 deg. C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

  3. Nanostructural evolution of Cr-rich precipitates in a Cu-Cr-Zr alloy during heat treatment studied by 3 dimensional atom probe

    DEFF Research Database (Denmark)

    Hatakeyama, Masahiko; Toyama, Takeshi; Nagai, Yasuyoshi

    2008-01-01

    Nanostructural evolution of Cr (Cr-rich) precipitates in a Cu-0.78%Cr-0.13%Zr alloy has been studied after aging and overaging (reaging) by laser assisted local electrode 3 dimensional atom probe (Laser-LEAP). This material is a candidate for the first wall and divertor components of future fusion...

  4. Recrystallization Behavior of CoCrCuFeNi High-Entropy Alloy

    Science.gov (United States)

    Park, Nokeun; Watanabe, Ikuto; Terada, Daisuke; Yokoyama, Yoshihiko; Liaw, Peter K.; Tsuji, Nobuhiro

    2015-04-01

    We investigated the recrystallization behavior of a cold-rolled CoCrCuFeNi high-entropy alloy (HEA). Two different face-centered cubic phases having different chemical compositions and lattice constants in the as-cast specimen have different chemical compositions: One phase was the Cu-lean matrix and the other was the Cu-rich second phase. The second phase remained even after a heat treatment at 1373 K (1100 °C) and Cu enriched more in the Cu-rich second phase. The calculated mixing enthalpies of both Cu-lean and Cu-rich phases in the as-cast and heat-treated specimens explained that Cu partitioning during the heat treatment decreased the mixing enthalpy in both phases. In the specimens 90 pct cold rolled and annealed at 923 K, 973 K, and 1073 K (650 °C, 700 °C, and 800 °C), recrystallization proceeded with increasing the annealing temperature, and ultrafine recrystallized grains with grain sizes around 1 μm could be obtained. The microhardness tended to decrease with increasing the fraction recrystallized, but it was found that the microhardness values of partially recrystallized specimens were much higher than those expected by a simple rule of mixture between the initial and cold-rolled specimens. The reason for the higher hardness was discussed based on the ultrafine grain size, sluggish diffusion expected in HEAs, and two-phase structure in the CoCrCuFeNi alloy.

  5. Microstructural and electrical investigation of Cu-Ni-Cr alloys obtained by powder metallurgy method

    Energy Technology Data Exchange (ETDEWEB)

    Carrio, Juan A.G.; Carvalhal, M.A.; Ayabe, L.M.; Monteiro, W.A., E-mail: jgcarrio@mackenzie.br [Universidade Presbiteriana Mackenzie (UPM/CCH), Sao Paulo, SP (Brazil). Centro de Ciencias e Humanidades. Dept. de Fisica; Silva, L.C.E. da; Silva Junior, R.V., E-mail: fisica.cch@mackenzie.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    The aim of this work, using the powder metallurgy process, is to synthesize metallic alloys with high mechanical strength and high electric conductivity, after melting optimizing and thermal treatments. The Cu-Ni-Cr (wt%) alloys are characterized in their mechanical and electrical properties as well as the obtained microstructure. Through the process of powder metallurgy, contacts and structural parts can be obtained. The alloys elements are added to copper with the intention to improve their strength, ductility and thermal stability, without causing considerable damages in their form, electrical and thermal conductivity, and corrosion resistance. The metallic powders were mixed for a suitable time and then they were pressed in a cold uniaxial pressing (1000 kPa). Afterwards, the specimens were sintered in temperatures varying from 700 up to 800 deg C under vacuum. At last, the samples were homogenized at 550 deg C under vacuum, for special times. The comparative analysis is based on the sintered density, densification parameter, hardness, macrostructures and microstructures of the samples. The alloys were characterized by optical microscopy, X-rays powder diffraction, electrical conductivity and Vickers hardness. (author)

  6. Phytoremediation of Cd, Cr, Cu, Mn, Fe, Ni, Pb and Zn from aqueous solution using Phragmites cummunis, Typha angustifolia and Cyperus esculentus.

    Science.gov (United States)

    Chandra, Ram; Yadav, Sangeeta

    2011-07-01

    A comparative bioaccumulation pattern and ultra structural changes were studied in Phragmites cummunis, Typha angustifolia and Cyperus esculentus in mixed metals solution of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). P. cummunis was observed to be a shoot accumulator for Cr, Fe, Mn, Ni, Pb, and Zn. However, T. angustifolia was found to be a root accumulator for Cd, Cr, Cu, Fe, Ni and Pb. In addition, C. esculentus also accumulated most of the tested heavy metals in the roots, while Mn and Fe were translocated up to leaves. Further, the long term metal treatment showed maximum accumulation of all heavy metals in P. cummunis followed by T. angustifolia and C. esculentus. Among heavy metals, Fe was accumulated maximum, i.e., >1000 microg g(-1) by all three plants. Simultaneously, the adverse effects on biochemical parameters were noted earlier in C. esculentus than T. angustifolia and P. cummunis. Ultra structural observation showed the cellular changes in wetland plants after longer exposure. Results revealed that P. cummunis and T. angustifolia had more potential for tested metals than C. esculentus. This study established that these wetland plants could be used for heavy metals phytoremediation from metal containing industrial wastewater.

  7. Transparent ferrimagnetic semiconducting CuCr2O4 thin films by atomic layer deposition

    Science.gov (United States)

    Tripathi, T. S.; Yadav, C. S.; Karppinen, M.

    2016-04-01

    We report the magnetic and optical properties of CuCr2O4 thin films fabricated by atomic layer deposition (ALD) from Cu(thd)2, Cr(acac)3, and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr2O4 films are interesting material candidates for various frontier applications.

  8. Transparent ferrimagnetic semiconducting CuCr2O4 thin films by atomic layer deposition

    Directory of Open Access Journals (Sweden)

    T. S. Tripathi

    2016-04-01

    Full Text Available We report the magnetic and optical properties of CuCr2O4 thin films fabricated by atomic layer deposition (ALD from Cu(thd2, Cr(acac3, and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr2O4 films are interesting material candidates for various frontier applications.

  9. Computer simulations of nanoindentation in Mg-Cu and Cu-Zr metallic glasses

    DEFF Research Database (Denmark)

    Paduraru, Anca; Andersen, Ulrik Grønbjerg; Thyssen, Anders

    2010-01-01

    The formation of shear bands during plastic deformation of Cu0.50Zr0.50 and Mg0.85Cu0.15 metallic glasses is studied using atomic-scale computer simulations. The atomic interactions are described using realistic many-body potentials within the effective medium theory, and are compared with similar...... simulations using a Lennard-Jones description of the material. The metallic glasses are deformed both in simple shear and in a simulated nanoindentation experiment. Plastic shear localizes into shear bands with a width of approximately 5 nm in CuZr and 8 nm in MgCu. In simple shear, the shear band formation...

  10. In-situ composite Cu-Cr contact cables with high strength andhigh conductivity

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In order to develop a new type of contact cable with high strength and high electrical conductivity, Cu-Cr alloy series were selected as materials and Cu-Cr alloy castings were produced by means of directional solidification continuous casting (DSCC) process. The results show that the fibrillar strengthening phase, β-Cr, orderly arranges among the copper matrix phase along the wire direction; and a microstructure of in-situ composite forms, which retains the basic property of good conductivity of the copper matrix and meanwhile obtains the strengthening effect of β-Cr phase. The production technology as well as the mechanical property, electrical property, and synthetic property of the in-situ composite contact cables was discussed.

  11. Reduction of Cr(VI) to Cr(III) by wetland plants: Potential for in situ heavy metal detoxification

    Energy Technology Data Exchange (ETDEWEB)

    Lytle, C.M.; Qian, J.H.; Hansen, D.; Zayed, A.; Terry, N. [Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology; Lytle, F.W. [The EXAFS Co., Pioche, NV (United States); Yang, N. [Sandia National Labs., Livermore, CA (United States)

    1998-10-15

    Reduction of heavy metals in situ by plants may be a useful detoxification mechanism for phytoremediation. Using X-ray spectroscopy, the authors show that Eichhornia crassipes (water hyacinth), supplied with Cr(VI) in nutrient culture, accumulated nontoxic Cr(III) in root and shoot tissues. The reduction of Cr(VI) to Cr(III) appeared to occur in the fine lateral roots. The Cr(III) was subsequently translocated to leaf tissues. Extended X-ray absorption fine structure of Cr in leaf and petiole differed when compared to Cr in roots. In roots, Cr(III) was hydrated by water, but in petiole and more so in leaf, a portion of the Cr(III) may be bound to oxalate ligands. This suggests that E. crassipes detoxified Cr(VI) upon root uptake and transported a portion of the detoxified Cr to leaf tissues. Cr-rich crystalline structures were observed on the leaf surface. The chemical species of Cr in other plants, collected from wetlands that contained Cr(VI)-contaminated wastewater, was also found to be Cr(III). The authors propose that this plant-based reduction of Cr(VI) by E. crassipes has the potential to be used for the in situ detoxification of Cr(VI)-contaminated wastestreams.

  12. Prediction of Properties in Thermomechanically Treated Cu-Cr-Zr Alloy by an Artificial Neural Network

    Institute of Scientific and Technical Information of China (English)

    Juanhua SU; Qiming DONG; Ping LIU; Hejun LI; Buxi KANG

    2003-01-01

    A supervised artificial neural network (ANN) to model the nonlinear relationship between parameters of thermomechanical treatment processes with respect to hardness and conductivity properties was proposed for Cu-Cr-Zr alloy. The improved model was developed by the Levenberg-Marquardt training algorithm. A basic repository on the domain knowledge of thermomechanical treatment processes is established via sufficient data acquisition by the network. The results showed that the ANN system is an effective way and can be successfully used to predict and analyze the properties of Cu-Cr-Zr alloy.

  13. Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds

    Indian Academy of Sciences (India)

    U Turgut

    2004-11-01

    Chemical effects on the K shell fluorescence yields of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were excited using 59.5 keV energy photons from a 241Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 160 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (K) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.

  14. Microstructure and Tribological Behaviour of CrCuFeNiTi High Entropy Alloys

    OpenAIRE

    Sobiyi Kehinde; Bodunrin Michael; Akinlabi Esther; Obadele Babatunde

    2016-01-01

    The microstructure, hardness and wear performance of CrCuFeTiNi high entropy alloy were evaluated. The alloy was produced by mixing constituent elements, consolidated and melted using vacuum arc furnace. The X-ray diffraction analysis confirmed that the alloy is composed of FCC and BCC simple phases. The microstructure contains three regions that were rich in Cu, Cr and Fe which resulted from segregation of constituent elements. The Vickers micro hardness of the alloy was determined as HV0.5 ...

  15. New type of Schottky diode-based Cu-Al-Mn-Cr shape memory material films

    Science.gov (United States)

    Aksu Canbay, C.; Dere, A.; Mensah-Darkwa, Kwadwo; Al-Ghamdi, Ahmed; Karagoz Genç, Z.; Gupta, R. K.; Yakuphanoglu, F.

    2016-07-01

    Cr-doped CuAlMn shape memory alloys were produced by arc melting method. The effects of Cr content on microstructure and transformation parameters of were investigated. The alloys were characterized by X-ray analysis, optical microscope observations and differential scanning calorimetry measurements. The grain size of the alloys was decreased by the addition of Cr into CuAlMn alloy system. The martensite transformation temperature was shifted both the lower temperature and higher temperature with the addition of chromium. This change was explained on the basis of the change in the thermodynamics such as enthalpy, entropy and activation energy values. The obtained results indicate that the phase transformation temperatures of the CuAlMn alloy system can be controlled by addition of Cr. We fabricated a Schottky barrier diode and observed that ideality factor and barrier height increase with increasing temperature. The diodes exhibited a thermal sensor behavior. This indicates that Schottky diode-based Cu-Al-Mn-Cr shape memory material films can be used as a sensor in high-temperature measurement applications.

  16. Relation Between pH and Desorption of Cu, Cr, Zn, and Pb from Industrially Polluted Soils

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Hansen, Henrik K.; Jensen, Pernille Erland

    2009-01-01

    . It was evident that Cu, Pb, and Zn started to desorb at a higher pH from calcareous soils than from soils with low carbonate content. The mechanism responsible for this is co-precipitation of heavy metals in the carbonates. When the carbonates are dissolved at a relatively high pH of about 5, the co......Desorption of Cu, Cr, Pb, and Zn from industrially polluted soils as a result of acidification is in focus. The eight soils of the investigation vary greatly in composition and heavy metal concentration/combination. Three soils had elevated concentrations of Cu, Pb, and Zn; regardless of pollution...... level, pollution origin, and soil type, the order for desorption as pH decreased was Zn > Cu > Pb. Turning to a single heavy metal in different soils, there was a huge difference in the pH at which the major desorption started. The variation was most significant for Pb where, e.g., less than 10...

  17. Removal of Cr(III), Ni(II) and Cu(II) by poly(gamma-glutamic acid) from Bacillus subtilis NX-2.

    Science.gov (United States)

    Yao, Jun; Xu, Hong; Wang, Jun; Jiang, Min; Ouyang, Pingkai

    2007-01-01

    Poly(gamma-glutamic acid) (gamma-PGA) derived from Bacillus subtilis NX-2 was investigated as a sorbent for heavy metal ions in batch adsorption experiments. The results showed that the heavy metal adsorption capacity of gamma-PGA enhanced with the increase of pH, in the following order: Cr(III) > Cu(II) > Ni(II), within the pH range 3-5. The Langmuir sorption model effectively described the metal sorption of y-PGA through the experiments of isotherm sorption, and it was deduced that the affinity of gamma-PGA for metals was following the sequence: Cr(III) > Cu(II) > Ni(II). Gamma-PGA was also used to trap trace amounts of heavy metals from the electroplating wastewater, which were difficult to be entirely removed by the traditional hydroxide precipitation method. The results showed that Cr(III) and Ni(II) in the electroplating effluent decreased from 3.07 and 9.46 mg/l to 0.15 and 1.01 mg/l, respectively, and the treated solutions reached the effluent standard. Therefore, gamma-PGA is satisfactory as a well biosorbent for the removal of heavy metals. The adsorption mechanism of gamma-PGA binding heavy metals was also studied using HyperChem simulation and FT-IR.

  18. A kinetic and mechanistic study into the formation of the Cu-Cr layered double hydroxide.

    Science.gov (United States)

    Williams, Gareth R; Clout, Alexander; Burley, Jonathan C

    2013-06-14

    The formation of the layered double hydroxide [Cu2Cr(OH)6]Cl·yH2O from the reaction between CuO and aqueous CrCl3·6H2O was explored using synchrotron X-ray diffraction and ex situ analyses. The use of hard X-rays permitted time-resolved in situ studies to be performed as the reaction proceeded under a range of conditions. Additional information was obtained from ex situ experiments in which aliquots of the reaction mixture were removed, quenched, and subsequently analysed by laboratory X-ray diffraction, IR, UV-visible, and atomic emission spectroscopies. On the basis of these data, it is proposed that the reaction involves three steps. First, the solid CuO starting material is hydrolysed to give Cu(OH)2 chains, releasing Cu(2+) ions into solution. The Cu hydroxide chains subsequently condense with aqueous Cr(3+) species, Cl(-) ions and water molecules to give a hydrated form of the LDH. This material then extrudes some water to form a phase with a reduced interlayer spacing.

  19. Accumulation of Zn, Pb, Cu, Cr and Ni in Sediments Between Roots of the Tagus Estuary Salt Marshes, Portugal

    Science.gov (United States)

    Ca çador, Isabel; Vale, Carlos; Catarino, Fernando

    1996-03-01

    Sediment cores of 60 cm length were collected from two Tagus estuary salt marshes. At each salt marsh, samples were taken from a non-vegetated zone and one from each of areas dominated by Halimione portulacoides, Spartina maritimaand Arthrocnemum fruticosum.Cores were sliced in situand, at each sediment layer, redox potential and pH were measured, and the organic matter content (LOI), grain size, and concentrations of Zn, Cu, Pb, Ni and Cr were determined. Sediment between roots and non-vegetated sediments of the same depth (5 -15 cm) were extracted with several acid solutions, and the metal concentrations were compared. Metal residues were determined in roots of vascular plants. Sediment between roots was more oxidative, more acidic and richer in organic matter than non-vegetated sediment. Profiles of Zn, Pb and Cu concentrations in vegetated sediments differed from those recorded in non-vegetated areas: at subsurface layers (where root density is higher), Zn, Pb and Cu were enriched. The percentages of Zn, Pb and Cu removed by acetic acid, nitric acid and DTPA extractions from sediment between roots were much lower than those from non-vegetated sediments, being preferentially linked to the residual fraction. Chromium and Ni behave differently no subsurface enrichment being found and their associations being similar in the two types of sediment. Furthermore, Ni concentrations in roots were much lower than in bulk sediments, while levels of Zn and Pb were similar and Cu values higher. These results point out that plants are an important feature for metal accumulation in salt marshes.

  20. Cr, Cu, Mn, Mo, Ni, and Steel Price Drivers

    Science.gov (United States)

    Papp, John F.; Corathers, Lisa A.; Edelstein, Daniel L.; Fenton, Michael D.; Kuck, Peter H.; Magyar, Michael J.

    2007-01-01

    Summary This report contains the 55 slide images from a presentation made by the author at the meeting of the Metal Powder Industries Federation held in Denver, CO, on May 15, 2007. The Metal Powder Industries Federation (MPIF) invited the U.S. Geological Survey (USGS) to speak at their annual meeting about the price drivers for chromium, copper, manganese, molybdenum, nickel, and steel. These metals are of interest to MPIF because the prices of these raw materials used by their industry were at historically high levels. Because the USGS closely monitors, yet neither buys nor sells, metal commodities, it is an unbiased source of metal price information and analysis. The authors used information about these and other metals collected and published by the USGS (U.S. production, trade, stocks, and prices) and about consumption and stocks internationally by country from industry organizations that publish such information, because metal markets are influenced by activities and events over the entire globe. By seeking a common cause for common behavior among the various metal commodities, the authors found that major price drivers on metal commodities were inflation, major international events such as wars and recessions, and major national events such as the dissolution of the Soviet Union in 1991 and economic growth in China, which started with the open door policy in the 1970s but did not have significant market impact until starting in the 1990s. Metal commodity prices also responded to commodity-specific events.

  1. Health Risk Assessment of Fe, Mn, Cu, Cr in Drinking Water in some Wells and Springs of Shush and Andimeshk, Khuzestan Province, Southern Iran

    Directory of Open Access Journals (Sweden)

    Mohamad Sakizadeh

    2016-02-01

    Full Text Available Background: In the current study,the hazard quotient, the hazard index (HI and spatial variations of Fe,Mn,Cu and Cr in drinking water sources of Andimesk-Shush, Khuzestan Province, Southern Iranaquifer were assessed. Methods: We compared theconcentrations of aforementioned heavy metals in wells and springs inAndimeshk and Shush regions. The non-carcinogenic risk assessment of heavy metals was implemented usingUnited States Environmental Protection Agency (USEPA index.The spatial maps in the area were developed by geostatistical methods. Results: Mean concentrations of heavy metals in groundwater sources of the study area in decreasing order was as follows: Cu >Mn> Fe> Cr. Except for iron,mean heavy metal concentrations were higher than the standard levels. Manganese concentration in 41.5% of the samples exceeded the permissible limits. Copper was higher than the safety limit in 74% of the samples, and chromium in 54% of the cases. The spatial pattern of heavy metals concentrations indicated higher concentrations in the southern parts of the region. The mean hazard quotients of most samples for the four heavy metals were lower than one, indicating that there was no immediate threat due to the exposure to these heavy metals. The calculated accumulated hazards of these heavy metals produced different results, with hazard indices of higher than one. Conclusion: The accumulated hazard indicesfor the evaluated metals were higher than one, indicating that chronic ingestion of these waters threatens the health of local consumers on the long run.

  2. CuSnNiCr真空钎焊金刚石界面微结构分析%Interfacial Microstructure of Diamond Vacuum Brazing with CuSnNiCr

    Institute of Scientific and Technical Information of China (English)

    卢金斌; 贺亚勋; 张旺玺; 穆云超; 丁文锋; 钟素娟; 马佳

    2016-01-01

    为降低钎焊金刚石的热损伤和制造成本,采用 CuSnNiCr 单质金属粉作为钎料,对金刚石磨粒进行了钎焊实验.采用SEM、EDS及 XRD 对金刚石焊后界面微结构、钎料组织进行了分析.结果表明:适合钎焊金刚石的活性成分为 Cu75 Sn15 Ni5 Cr5,该钎料能与金刚石实现化学冶金结合,熔点适中,润湿性较好.金刚石焊后形貌完整,表面基本光滑,表面生成了连续片状(Cr,Fe)7 C3.钎料凝固过程先结晶出α-Cu枝晶,经包晶转变和共析转变,形成了α-Cu 枝晶、Cu5.6 Sn和共析α-Cu,钎料的显微硬度大约为200~250HV0.2.%In order to reduce the heat damage of diamond and manufacturing cost, using CuSnNiCr metal powder as filler and the experiments of brazing diamond abrasive grain were carried out.SEM,EDS and XRD were used to analyze the microstructure of diamond and brazing filler.The results show that the active component of the brazing diamond is Cu75Sn15Ni5Cr5,the melting point of the brazing filler is suitable for brazing diamond,and it can realize the chemical metallurgical bond-ing with diamond.The morphology of diamond is complete,the surface is smooth,and the surface of the diamond is as (Cr,Fe)7 C3 .The brazing filler solidification process of crystallizedα-Cu dendrite, peritectic transformation and eutectoid transformation,the formation of dendrite,Cu5.6 Sn,α-Cu and eutectoidα-Cu,the microhardness of the brazing filler is about 200~250HV0.2.

  3. Corrosion behavior of a CuCrNiAl alloy in the presence of NaCl deposit

    Institute of Scientific and Technical Information of China (English)

    XU Tao; CHANG Limin; LIU Jianhua

    2006-01-01

    The corrosion behavior of a CuCrNiAl alloy with NaCl deposit at 700 and 900℃ was studied by means of metalloscope, XRD, SEM/EDX, and thermogravimetric analysis. The results indicated that the corrosion of the CuCrNiAl alloy beneath the NaCl deposit is severe; the corrosion production is loose and easy to scale off; the Cr phase is easier to erode than the Cu phase, and the contents of Cu and Cr decrease when the content of Ni increases in the matrix of the alloy beneath the corrosion region. The effects of distortion on the corrosion of the CuCrNiAl alloy were discussed, and the acceleration mechanisms of NaCl on the corrosion were also discussed.

  4. Effects of Cu Layer Width on the Giant Magneto-impedance Effect in Sandwich FeCuNbCrSiB/Cu/FeCuNbCrSiB Films With a Meander Line Structure%Cu层宽度对弯曲型三明治结构FeCuNbCrSiB/Cu/FeCuNbCrSiB多层膜巨磁阻抗效应的影响

    Institute of Scientific and Technical Information of China (English)

    张亚民; 陈吉安; 周勇; 丁文; 王明军; 高孝裕; 周志敏

    2005-01-01

    采用射频磁控溅射方法和微细加工工艺制备了不同Cu层宽度的弯曲型三明治结构的FeCuNbCrSiB/Cu/FeCuNbCrSiB多层膜,在频率1~40MHz下研究了Cu层宽度对多层膜的纵向和横向巨磁阻抗效应的影响.结果表明,弯曲型三明治结构多层膜的巨磁阻抗率随Cu层宽度的变化具有显著的变化,在频率10MHz、磁场12kA/m下,当Cu层宽度为0.4mm时,纵向、横向巨磁阻抗率分别达-57%、-65%.

  5. Effect of heat treatments on precipitate microstructure and mechanical properties of CuCrZr alloy

    DEFF Research Database (Denmark)

    Singh, B.N; Edwards, D.J.; Tähtinen, S.

    2004-01-01

    A number of specimens of CuCrZr alloy was prime aged and then overaged at 600oC for 1, 2 and 4 hours and for 4 hours at 700 and 850oC. After different heat treatments, both the precipitate microstructure and mechanical properties were characterized.Mechanical properties were determined at 50...

  6. Crystallite size dependence of thermoelectric performance of CuCrO2

    NARCIS (Netherlands)

    Ngo, T. N. M.; Palstra, T. T. M.; Blake, G. R.

    2016-01-01

    The layered delafossite CuCrO2 has attracted attention as a promising thermoelectric material because its electrical conductivity can be greatly increased by doping. Here we study the effect of crystallite size and morphology on the thermal conductivity, Seebeck coefficient and electrical resistivit

  7. Erosion corrosion of CuCrZr specimens exposed for simulated ITER operational conditions

    Directory of Open Access Journals (Sweden)

    C. Obitz

    2016-12-01

    The erosion corrosion and release rates of CuCrZr and CuCrZr/316L(N-IG joints were derived from weight change data and metallographic examinations of specimens after autoclave exposures at 110°C, 150°C and 250°C at reducing-, oxidizing- and cyclic redox water chemistry conditions. Reducing water chemistry represents periods considered as the nominal off-plasma operational conditions while the oxidizing environment simulates situations when the plasma is active. The cyclic redox conditions represent periods with shorter cycles simulating plasma activations with subsequent periodical variation of the water chemistry from reducing to oxidizing. The erosion corrosion rates for CuCrZr at active plasma conditions were 20 and 40µm/year at 110 and 150°C. At 250°C the corresponding rate was much higher. This result gives important information on what may happen if, for example, a First Wall panel is exposed to an unexpectedly high heat flux. Under reducing conditions the erosion corrosion rates were 3µm/year and 20µm/year at 110°C and 250°C respectively. The results at 250°C under off-plasma conditions reveal that the effect of erosion corrosion also has to be taken into account during baking. Cyclic conditions with respect to oxidant content turned out to be the most demanding environment (more demanding than pure oxidizing conditions for the CuCrZr-alloy. Erosion corrosion rates of 90µm/year and 370µm/year at 110 and 150°C were recorded respectively. The highest temperature 250°C was not tested. This raise the question whether measures should be introduced that renders the system either oxidizing or reducing. In summary, the erosion corrosion rates recorded for CuCrZr under simulated ITER coolant water conditions are high, especially during plasma operation. For comparison it can be mentioned that corrosion rates of structural materials in the primary loop of light water reactors generally are considerably lower than 1µm/year. The estimated rates for CuCr

  8. Immobilization and Phytoavailability of As, Cr and Cu in CCA ...

    African Journals Online (AJOL)

    user

    natural rubber compounds using rubber seed shell carbon as filler was carried out. ... terms of pH, moisture content, bulk density, loss on ignition, conductivity, metal content and surface area. .... vulcanizates for the test specimens. Table 2: ...

  9. Investigation of Cu-based Infiltration Coatings for Metal-supported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Reddy Sudireddy, Bhaskar; Persson, Åsa Helen;

    2013-01-01

    Metal-supported solid oxide fuel cells are candidates for the next generation of SOFCs. However, the cell design with an FeCr/YSZbased anode backbone suffers from corrosion when the cells are run at high fuel utilization, which limits the long term durability. In this work, new infiltration...... coatings based on Cu in combination with Ni:Ce0.8Gd0.2O1.9 (Ni:CGO) have been studied. The candidates for a corrosion resistant coating should limit the formation of Cr2O3 on the surface of FeCr particles. Promising fuel cell performance with an ASR of 0.5 _cm2 was obtained at 650 ºC with H2 as fuel...

  10. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system

    Directory of Open Access Journals (Sweden)

    S. K. Dhar

    2016-05-01

    Full Text Available Ti3CrCu4 is a new ternary compound which crystallizes in the tetragonal Ti3Pd5 structure type. The Cr atoms form square nets in the a-b plane (a = 3.124 Å which are separated by an unusually large distance c = 11.228 Å along the tetragonal axis, thus forming a -2-D Cr-sublattice. The paramagnetic susceptibility is characterized by a low effective moment, μeff = 1.1 μB, a low paramagnetic Curie temperature θP (below 7 K and a temperature independent χ0 = 6.7 x 10−4 emu/mol. The magnetization at 1.8 K increases rapidly with field nearly saturating to 0.2 μB/f.u. The zero field heat capacity C/T shows an upturn below 7 K (∼190 mJ/mol K2 at ∼0.1K which is suppressed in applied magnetic fields and interpreted as suggesting the presence of spin fluctuations. The resistivity at low temperatures shows non-Fermi liquid behavior. Overall, the experimental data thus reveal an unusual magnetic state in Ti3CrCu4, which likely has its origin in the layered nature of the Cr sub-lattice and ferromagnetic spin fluctuations. Density functional theoretical calculations reveal a sharp Cr density of states peak just above the Fermi level, indicating the propensity of Ti3CrCu4 to become magnetic.

  11. Theoretical approach to the magnetic properties of Mn(II), Cr(III), and Cu(II) complexes in the newly reported 12- and 15-membered macrocyclic ligands

    Indian Academy of Sciences (India)

    Ali Bayri; Mustafa Karkaplan

    2007-08-01

    The magnetic properties of Cu2+, Cr3+, and Mn2+ ions in the newly reported 12- and 15-membered macrocyclic complexes are analysed by a theoretical approach. The calculated magnetic moment and magnetic anisotropy for various situations, especially for Cu(II) ion, suggest that the magnetic properties may lead to a better interpretation about the geometry. It is also suggested that the zero-field splitting Hamiltonian may be used for magnetic properties of some metal ions, which have orbital singlet ground term in these complexes.

  12. Newly developed EMF cell with zirconia solid electrolyte for measurement of low oxygen potentials in liquid Cu-Cr and Cu-Zr alloys

    Directory of Open Access Journals (Sweden)

    Katayama I.

    2012-01-01

    Full Text Available In order to measure the very low oxygen potential by use of stabilized zirconia solid electrolyte emf method, a new cell construction was devised. The idea was based on Janke but a zirconia rod was used instead of the zirconia crucible which contacts liquid alloy electrode. The cell was used for determination of the oxygen potentials in liquid dilute Cu-Cr and Cu-Zr alloys. The reference electrode was Cr,Cr2O3. Emf measurements were performed in the temperature range of 1400-1580K and composition range of 0.198-3.10at%Cr-Cu alloys, and 1380-1465K, 0.085-0.761at%Zr-Cu alloys. The composition of liquid alloys were determined by picking up from the liquid alloys and ICP analysis. By use of the newly devised cell construction in this study, stable emf values were obtained at each temperature and alloy composition. Emf values were corrected by using the parameter for electronic contribution of the YSZ. Activity of Cr obeys Henry’s law and activity coefficient at infinitely dilute alloys of Cr in Cu-Cr alloys are: lng0 Cr =(3.80 at 1423K, (3.57 at 1473K, (3.38 at 1523K and (3.20 at 1573K. At 1423 K activity coefficient of Zr at infinitely diluted alloy is lnγo Zr = -4.0.

  13. [Effect of Cr (VI) anions on the Cu (II) adsorption behavior of two kinds of clay minerals in single and binary solution].

    Science.gov (United States)

    Liu, Juan-Juan; Liang, Dong-Li; Wu, Xiao-Long; Qu, Guang-Zhou; Qian, Xun

    2014-01-01

    The adsorption of Cu (II) on kaolinite and montmorillonite was investigated through batch adsorption experiment. Several adsorption models were employed to describe the adsorption of Cu (II) on the two clay minerals in single Cu (II) and Cu(II)-Cr (VI) binary solutions, and the impact of solution with various pH values on the adsorption of Cu (II) on the two target mineral clays was investigated in order to explain the environmental chemical behavior of heavy metals in soil and to provide theoretical basis in remediation of multi-element contaminated soil. The results indicated that the adsorption process of Cu (II) on kaolinite and montmorillonite in both single and binary solutions was fast at the beginning and then slowed down. Adsorption equilibrium was observed within 120 min. In both single and binary solutions, pseudo-second-order model (R2 > 0.983) showed the highest agreement with the adsorption of Cu (II) on the two mineral clays, followed by the intra-particle diffusion model and pseudo-first-order model. Both Intra-particle diffusion model and Boyd model illustrated that the film diffusion process was the rate-limiting step, which mainly occurred at the edge and surface of mineral clays. Copper adsorption on kaolinite was well fitted with the Freundlich equation (R2 > 0.971), which could be attributed to the heterogeneity of kaolinite surface with adsorption sites that have different energies of adsorption. Langmuir equation was best fitted with the isotherm for montmorillonite (R2 > 0.983), which indicated that the adsorption was on a single molecular layer or chemisorptions. In both single and binary solutions, the adsorption of Cu (II ) on the two clay minerals first increased and then decreased with the rising of pH values. The maximum adsorption amount was found at pH = 5.0, and was in the order of Qmon. > Qkao. and Q(Single-Cu) > Q(Cu-Cr binary). Cr (VI) in the solution reduced the adsorption of Cu (II), and the minimal influence of Cr (VI) on Cu

  14. Influence of Al{sub 2}O{sub 3} reinforcement on precipitation kinetic of Cu-Cr nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Sheibani, S., E-mail: ssheibani@ut.ac.ir [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ataie, A.; Heshmati-Manesh, S. [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Caballero, A.; Criado, J.M. [Instituto de Ciencia de Materiales de Sevilla, Departamento de Quimica Inorganica, CSIC - Universidad de Sevilla, Americo Vespucio 49 Sevilla (Spain)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Cr precipitation in Cu-1 wt.% Cr solid solution is based on nucleation and growth models. Black-Right-Pointing-Pointer The overall ageing process is accelerated by the presence of Al{sub 2}O{sub 3} reinforcement. Black-Right-Pointing-Pointer Al{sub 2}O{sub 3}-Cu interfaces act as primary nucleation sites. Black-Right-Pointing-Pointer Structural defects act as secondary nucleation sites. - Abstract: In this paper, the kinetic of precipitation process in mechanically alloyed Cu-1 wt.% Cr and Cu-1 wt.% Cr/3 wt.% Al{sub 2}O{sub 3} solid solution was compared using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The ageing kinetics in Cu-Cr and Cu-Cr/Al{sub 2}O{sub 3} can be described using Johnson-Mehl-Avrami (JMA) and Sestak-Berggren (SB) models, respectively. These different behaviors have been discussed in details. It was found that in presence of Al{sub 2}O{sub 3} reinforcement, the ageing activation energy is decreased and the overall ageing process is accelerated. This behavior is probably due to higher dislocation density previously obtained during ball milling and Al{sub 2}O{sub 3}-Cu interface. TEM observations confirm that Al{sub 2}O{sub 3}-Cu interface and structural defects act as a primary and secondary nucleation sites, respectively.

  15. Thermal Decomposition Studies of Layered Metal Hydroxynitrates (Metal: Cu, Zn, Cu/Co, and Zn/Co

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2015-01-01

    Full Text Available Layered metal hydroxynitrates and mixed metal hydroxynitrates (copper/cobalt hydroxynitrates and zinc/cobalt hydroxynitrates at different mole ratios were synthesized by hydrolysis of urea and metal nitrates at 140°C. Layered metal hydroxyl nitrates derive their structure from brucite mineral and generally crystallize in hexagonal and monoclinic phases. Isothermal decomposition studies of Cu2(OH3(NO3, Co2(OH3(NO3, Cu1.5Co0.5(OH3(NO3, Cu1.34Co0.66(OH3(NO3, Zn5(OH8(NO32(H2O2, Zn3.75Co1.25(OH8(NO32(H2O2, and Zn3.35Co1.65(OH8(NO32(H2O2 samples were carried out at different intervals of temperature and the structural transformations during the process were monitored using powder X-ray diffractograms. Biphasic mixture of metal hydroxynitrate/metal oxide is observed in case of cobalt/zinc based layered hydroxynitrates, while copper hydroxynitrate or copper/cobalt metal hydroxynitrate decomposes in a single step. The decomposition temperatures of layered metal hydroxynitrates and mixed layered metal hydroxides depend on the method of preparation, their composition and the nature of metal ion, and their coordination.

  16. Study of Magnetic Entropy Changes in Gd1-x Tx ( T = Ti, Cr, Fe and Cu) Alloys

    Institute of Scientific and Technical Information of China (English)

    Wang Dunhui; Huang Songling; Han Zhida; Zhang Jianrong; Du Youwei

    2004-01-01

    Magnetic refrigeration techniques based on the magnetocaloric effect (MCE) were demonstrated as a promising alternative to conventional vapour-cycle refrigeration.Recently, scientists focused their research on room temperature magnetic refrigeration.The rare earth Gd metal is regarded as a prototype for room temperature magnetic refrigerant.Considering the various requirements in application, it is necessary to search for the magnetic refrigerant possessing qualities as good as Gd but having different Tc above or below room temperature.In this article, we report the magnetic entropy changes in Gd1 -xTx(T = Ti, Cr, Fe and Cu) alloys.With a small quantity of T atoms introduced in Gd, the Curie temperature increases.The values of magnetic entropy change in these alloys are almost the same as or a little less than that of Gd.But the refrigerant capacities of these alloys are obviously larger than that of Gd.All these facts suggest that Gd1-xTx(T = Ti, Cr, Fe and Cu) alloys may be good refrigerants for room temperature magnetic refrigeration.

  17. Microstructure, impurity and metal cap effects on Cu electromigration

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-19

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

  18. Metabolismo del Mg, Cu, Zn, Cr, Mn, y Ni en la diabetes melitus

    OpenAIRE

    1995-01-01

    En los últimos años, a los elementos traza y al mg se las ha implicado en la patologenesis de las complicaciones crónicas de la diabetes mellitus (dm). Las alteraciones del estado mineral asociadas a la dm podrían estar influidas, entre otros factores, por el grado de control metabólico y la asociación, o no, de otras patologías metabólicas como la hipertensión arterial (hta), la dislipemia y la obesidad. A pesar de que el mg, cu, zn, cr, mn y ni son cationes de localización principalmente in...

  19. The influence of 3d-metal alloy additions on the elastic and thermodynamic properties of CuPd3

    Institute of Scientific and Technical Information of China (English)

    Huang Shuo; Zhang Chuan-Hui; Sun Jing; Shen Jiang

    2013-01-01

    Embedded-atom method (EAM) potentials are used to investigate the effects of alloying (e.g.3d-metals) on the trends of elastic and thermodynamic properties for CuPd3 alloy.Our calculated lattice parameter,cohesive energy,and elastic constants of CuPd3 are consistent with the available experimental and theoretical data.The results of elastic constants indicate that all these alloys are mechanically stable.Further mechanical behavior analysis shows that the additions of Cr,Fe,Co,and Ni could improve the hardness of CuPd3 while V could well increase its ductility.Moreover,in order to evaluate the thermodynamic contribution of 3d-metals,the Debye temperature,phonon density of states,and vibrational entropy for CuMPd6 alloy are also investigated.

  20. CHARACTERISATION OF Cr DOPED CuO NANOPARTICLES AND ITS PERFORMANCE IN SOLAR CELL

    OpenAIRE

    2016-01-01

    Pure and Cr2+doped Copper oxide (CuO) nanoparticles were synthesized by simple precipitation method and subjected to photovoltaic activity by forming nanopowder –thin film as light absorbing  layer  on an  indigenously fabricated heterojunction by Doctor-Blade method.  Effect of concentration of the dopant (2, 4, and 6 mol%)  on the properties of CuO was analyzed from X-Ray Diffraction pattern (XRD), Scanning Electron Microscopy(SEM) Energy Dispersive Analysis (EDAX), UV-Vis studies and Photo...

  1. Production of Renewable Hydrogen from Glycerol Steam Reforming over Bimetallic Ni-(Cu,Co,Cr Catalysts Supported on SBA-15 Silica

    Directory of Open Access Journals (Sweden)

    Alicia Carrero

    2017-02-01

    Full Text Available Glycerol steam reforming (GSR is a promising alternative to obtain renewable hydrogen and help the economics of the biodiesel industry. Nickel-based catalysts are typically used in reforming reactions. However, the choice of the catalyst greatly influences the process, so the development of bimetallic catalysts is a research topic of relevant interest. In this work, the effect of adding Cu, Co, and Cr to the formulation of Ni/SBA-15 catalysts for hydrogen production by GSR has been studied, looking for an enhancement of its catalytic performance. Bimetallic Ni-M/SBA-15 (M: Co, Cu, Cr samples were prepared by incipient wetness co-impregnation to reach 15 wt % of Ni and 4 wt % of the second metal. Catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES, N2-physisorption, X-ray powder diffraction (XRD, hydrogen temperature programmed reduction (H2-TPR, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analyses (TGA, and tested in GSR at 600 °C and atmospheric pressure. The addition of Cu, Co, and Cr to the Ni/SBA-15 catalyst helped to form smaller crystallites of the Ni phase, this effect being more pronounced in the case of the Ni-Cr/SBA-15 sample. This catalyst also showed a reduction profile shifted towards higher temperatures, indicating stronger metal-support interaction. As a consequence, the Ni-Cr/SBA-15 catalyst exhibited the best performance in GSR in terms of glycerol conversion and hydrogen production. Additionally, Ni-Cr/SBA-15 achieved a drastic reduction in coke formation compared to the Ni/SBA-15 material.

  2. Preparation of Cu-based Bulk Metallic Glass Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    Yufeng SUN; Yuren WANG; Bingchen WEI; Weihuo LI

    2006-01-01

    Cu47Ti34Zr11Ni8 bulk metallic glass (BMG) matrix composites containing in situ formed TiC particles and δ-TiCu dendrite phase were developed by copper mold cast. The thermal stability and microstructure of the composites are investigated. Room temperature compression tests reveal that the composite samples exhibit higher fracture strength and distinct plastic strain of 0.2%~0.5%, comparing with that of the corresponding Cu47Ti34Zr11 Ni8 monolithic BMG.

  3. Magnetic properties of delafossite oxide: CuCr1-xTixO2

    Science.gov (United States)

    Majee, M. K.; Bhobe, P. A.; Nigam, A. K.

    2016-05-01

    In order to increase the possibility for technological applications of CuCrO2, there have been attempts to introduce ferromagnetic (FM) order by doping at B-site. With this aim, we present here study of polycrystalline CuCr1-xTixO2 with x=0.0, 0.05, 0.1. The samples have been prepared using solid state synthesis method and characterized for its crystal structure and magnetic properties. All the samples crystallize in the 2H delafossite structure with R-3m space group. Ti substitution causes the expansion of unit cell with increase in both the lattice constants. Antiferromagnetic ordering temperature is seen to decrease with increasing Ti. Ferromagnetic-like signature is obtained in one of the compositions at low applied magnetic field of 100 Oe.

  4. Creep of Uncoated and Cu-Cr Coated NARloy-Z

    Science.gov (United States)

    Walter, R. J.; Chiang, K. T.

    1998-01-01

    Stress rupture creep tests were performed on uncoated and Cu-30vol%Cr coated NARloy-Z copper alloy specimens exposed to air at 482 C to 704 C. The results showed that creep failure in air of unprotected NARloy-Z was precipitated by brittle intergranular surface cracking produced by strain assisted grain boundary oxidation (SAGBO) which in turn caused early onset of tertiary creep. For the protected specimens, the Cu-Cr coating remained adherent throughout the tests and was effective in slowing down the rate of oxygen absorption, particularly at the higher temperatures, by formation of a continuous chromium oxide scale. As the result of reducing oxygen ingress, the coating prevented SAGBO initiated early creep failure, extended creep deformation and increased the creep rupture life of NARloy-Z over the entire 482 C to 704 C test temperature range.

  5. Microstructure and Tribological Behaviour of CrCuFeNiTi High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Sobiyi Kehinde

    2016-01-01

    Full Text Available The microstructure, hardness and wear performance of CrCuFeTiNi high entropy alloy were evaluated. The alloy was produced by mixing constituent elements, consolidated and melted using vacuum arc furnace. The X-ray diffraction analysis confirmed that the alloy is composed of FCC and BCC simple phases. The microstructure contains three regions that were rich in Cu, Cr and Fe which resulted from segregation of constituent elements. The Vickers micro hardness of the alloy was determined as HV0.5 = 510 ± 7 MPa. The wear performance of the alloy was also studied using WC balls under two load conditions. The volume loss was evaluated, accompanied by analysis of the wear tracks and debris using SEM images and EDS. The main wear mechanisms were ploughing, adhesion and oxidation-dominated wear.

  6. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    Science.gov (United States)

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS.

  7. Efficient carbon dioxide electrolysis with metal nanoparticles loaded La0·75Sr0·25Cr0·5Mn0·5O3-δ cathodes

    Science.gov (United States)

    Zhu, Changli; Hou, Linxi; Li, Shisong; Gan, Lizhen; Xie, Kui

    2017-09-01

    Solid oxide electrolysis cells with La0·75Sr0·25Cr0·5Mn0·5O3-δ (LSCM) cathode can electrolyze CO2 to generate chemical fuels. Nevertheless, the cathode performance is limited by its electrocatalytic activity. In this work, metal nanoparticles including Ni, Cu and NiCu metals are successfully impregnated in LSCM electrode to improve its activity. XRD, XPS, SEM and TEM together confirm the metal nanocatalysts are homogeneously distributed on LSCM backbone and therefore create active electrochemical interface for CO2 splitting. Electrical properties of LSCM with impregnated metal nanoparticles are investigated and correlated to electrode performances. Electrochemical measurements show that the NiCu-LSCM demonstrates the optimum performance without degradation after operation for ∼100 h and ∼10 redox cycles. It is believed that the enhanced performance of CO2 electrolysis may be attributed to the synergetic effect of metal nanocatalyst and LSCM ceramic electrode.

  8. The Effects of Aging Precipitation on the Recrystallization of CuNiSiCr Alloy

    Institute of Scientific and Technical Information of China (English)

    LEI Jingguo; HUANG Jinliang; LIU Ping; JING Xiaotian; ZHAO Dongmei; ZHI Xiao

    2005-01-01

    The interaction between precipitation and recrystallization and its effect on the properties of the Cu-Ni-Si-Cr alloy during aging were discussed.The results show that the deformation results in much more dispersed precipitation of the phases. The precipitations have accelerating or retarding effects on the recrystallization. On the formation and growth of recrystallization, the precipitated phases are coarsed or dissolved in front of grain boundaries following a re-precipitation in the recrystallization area.

  9. Nanoindentation deformation of a bi-phase AlCrCuFeNi{sub 2} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yuan [School of Mechanical Engineering, Shanghai Dianji University, 200245 Shanghai (China); Zhao, Guangfeng [Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Wen, Xiyu [Center for Aluminum Technology, University of Kentucky, Lexington, KY 40511 (United States); Qiao, Junwei [Taiyuan University of Technology, Taiyuan, 030024 (China); Yang, Fuqian, E-mail: fyang0@engr.uky.edu [Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States)

    2014-09-01

    Highlights: • The AlCrCuFeNi{sub 2} HEA consisted of BCC solid solution and FCC solid solution. • The indentation hardness of the BCC crystals is larger than the FCC crystals. • The contact modulus of the FCC crystals is larger than the BCC crystals. - Abstract: High-entropy alloys (HEA) are multicomponent alloys with lattice structures, which have unique mechanical properties. Using X-ray diffraction, the structure of as cast AlCrCuFeNi{sub 2} HEA was characterized. The AlCrCuFeNi{sub 2} HEA consisted of body centered-cubic (BCC) solid solution and face centered-cubic (FCC) solid solution. Nanoindentation was used to characterize the indentation deformation of the FCC and BCC crystals in the AlCrCuFeNi{sub 2} HEA. Both the indentation hardness and the contact modulus of the FCC and BCC crystals decreased slightly with the increase in the indentation load and became constant for large indentation loads. For the indentation load larger than 500 μN, the contact modulus and the indentation hardness of the BCC crystals are 146 and 4.6 GPa, respectively, and the contact modulus and the indentation hardness of the FCC crystals are 207 and 2.8 GPa, respectively. The plastic energy dissipated in the nanoindentation increased with the indentation load and was proportional to the 1.77 and 1.88 power of the indentation load for the FCC and BCC crystals, respectively. The ratio of the dissipated plastic energy to the total energy in the indentations was a linear function of the ratio of the residual indentation depth to the corresponding maximum indentation depth. The slope of the energy ratio verse the indentation depth ratio for the BCC crystals is larger than that for the FCC crystals.

  10. Synthesis and Mössbauer characterization of Cu and Cr doped magnetites

    Directory of Open Access Journals (Sweden)

    Barrero, C. A.

    2003-12-01

    Full Text Available A detailed Mössbauer investigation of magnetites prepared under different hydrothermal conditions and doped with Cu and Cr is presented. The samples were characterized by means of room temperature Mössbauer spectrometry, infrared spectroscopy, and X-ray diffraction. Mössbauer results show that the hydrothermal method produces highy stoichiometric and relatively well-crystallized magnetites. The results suggest that the best samples are obtained when the alkaline solution is added quickly to the ferrous solution. It was also found that mixing the solutions under constant ultrasonic stirring produce magnetites with slightly better crystallinity and stoichiometry than the samples produced under magnetic or nitrogen bubbling stirring. The effect of the Cu and Cr on the hyperfine parameters is also presented and discussed.

    Se presenta una investigación Mössbauer detallada de magnetitas preparadas bajo diferentes condiciones hidrotermales y dopadas con Cu y Cr. Las muestras fueron caracterizadas utilizando la espectrometría Mössbauer a temperatura ambiente, espectroscopia infrarroja y difracción de rayos X. Los resultados Mössbauer muestran que el método hidrotermal produce magnetitas altamente estequiométricas y relativamente bien cristalizadas. Los resultados sugieren que las mejores muestras se obtienen cuando la solución alcalina se añade rápidamente a la solución ferrosa. Se encontró que la mezcla de las soluciones bajo agitación ultrasónica constante produce magnetitas con cristalinidad y estequiometría levemente mejores que las muestras producidas bajo agitación magnética o por burbujeo de nitrógeno. También se presentan y se discuten los efectos del Cu y del Cr en los parámetros hiperfinos.

  11. Evaluation of Cd, Cr, Cu, Ni, and Pb in selected cosmetic products from Jordanian, Sudanese, and Syrian markets.

    Science.gov (United States)

    Massadeh, A M; El-Khateeb, M Y; Ibrahim, S M

    2017-08-01

    There is no sufficient data that evaluate heavy metal content in cosmetic products in Jordan as well as Sudan and Syria. This study aims to assess metal levels which include Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), and Lead (Pb) in cosmetic products. These elements have draft limits because they are identified as potential impurities and are known to be toxic. This study aims to provide information to the population that may be beneficial to public health. Samples were collected from different brands obtained from markets in Jordan, Sudan, and Syria. Some of the selected cosmetic products were eyeliner, eye pencil, mascara, lipstick, powder, face cream, body cream, sun block, Vaseline, and the traditional eye cosmetic (kohl). The heavy metal content in these samples were determined by atomic absorption spectrometry (AAS). Based on analysis of variance analysis, a significant difference in heavy metal levels was found for samples obtained from Jordanian and Sudanese markets. The acid digestion method used in this study was based on procedures recommended by Nnorom et al. with some modifications as follows. (i) A weight of 2.0 g of cosmetic sample was dissolved in a mixture of 6 mL of high quality concentrated 69% nitric acid (HNO3; Merck, Darmstadt, Germany) and 4 mL of concentrated 37% hydrochloric acid (Scharlau, Spain) in a porcelain crucible and heated on a hotplate to near dryness. (ii) An aliquot of 15 mL HNO3 (1.00 M) was added to the digested sample and filtered through a Whatman No. 40 filter paper. (iii) The digested sample was transferred quantitatively into a 25 mL volumetric flask and then diluted with deionized water. (iv) Each digested sample was evaporated at 70 °C to about 1 mL and transferred into a polyethylene flask and diluted with 25 mL deionized water. (v) Blank was treated in the same procedure. In Jordan the concentration ranges of heavy metals in the collected samples were: Cd (0.03-0.10 μg/g), Cr (0.0-1.00

  12. Dynamic Embrittlement in Cu-Cr-Zr-Ti Alloy: Evidence of Intergranular Segregation of Sulphur

    Science.gov (United States)

    Chenna Krishna, S.; Radhika, K. V.; Tharian, K. Thomas; Swathi Kiranmayee, M.; Sudarshan Rao, G.; Jha, Abhay K.; Pant, Bhanu

    2013-08-01

    In the present investigation, Cu-0.6Cr-0.005Zr-0.0045Ti alloy was subjected to different heat treatment and thermomechanical treatment (TMT) to simulate the conditions experienced during brazing and forming, respectively. Grain coarsening was observed in the samples subjected to heat treatment, and grain refinement was observed in the samples subjected to TMT. Tensile tests conducted with these samples at room temperature and 600 °C have shown that Cu-Cr-Zr-Ti alloy was susceptible to dynamic embrittlement (DE). However, the observation was limited to coarse-grained samples (280-350 μm) at 600 °C. On the other hand, the fine-grained samples (20-40 μm) showed good ductility. Electron microscopy studies conducted on the tensile-tested specimens prone to DE indicated the presence of sulfur on the fractured surface and intergranular segregation of sulfur. Therefore, it can be inferred from the results that DE due to sulfur can occur in Cu-Cr-Zr-Ti alloy at elevated temperature for coarse-grained samples.

  13. Use of multivariate statistical tool for data processing in the analysis of Cu, Cr, Fe, Pb, Mo and Mg in lubricating oil by LIBS

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Luana F.N.; Sarkis, Jorge E.S.; Bordon, Isabela C.A.C., E-mail: ludemar1@hotmail.com, E-mail: jesarkis@ipen.br, E-mail: isabella.bordon@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Analysis of industrial lubricants is widely used for monitoring and predicting maintenance requirements in a broad range of mechanical systems. Laser induced breakdown spectroscopy has been used to evaluate the potentiality of the technique for the determination of metals in lubricating oils. Prior to quantitative analysis, the LIBS system was calibrated using standard samples containing the elements investigated (Cu, Cr, Fe, Pb, Mo and Mg). This study presents the usefulness of multivariate statistical techniques for evaluation and interpretation of large complex data sets in order to get more information about concentration of metals in oils lubricants is related to engine wear. (author)

  14. Avoidance Reaction of Penaeus Chinensis to Heavy Metals (Pb, Cr,Zn) and Heavy Metal Mixtures (Pb-Cr, Pb-Zn)

    Institute of Scientific and Technical Information of China (English)

    陈民山

    2001-01-01

    Study on the avoidance response of Penaeus chinensis to heavy metals (Pb, Cr, Zn) and heavy metal mixtures (Pb-Cr, Pb-Zn) is carred out using a Y-model avoidance apparatus. The concentrations calculated to induce 50% avoidance rate byPenaeus chinensis are 11.4, 33.2 and 238. 1 mg/L for Pb, Cr and Zn, respectively. Mixtures of Pb-Cr and Pb-Zn produce additive effect in the avoidance test using Penaeus chinesis. But when the mixed Pb-Zn solution has 0.5 toxic unit Pb and 0.5 toxic unit Zn, the mixture seems to have synergistic effect.

  15. Characterization of residues from thermal treatment of treated wood and extraction of Cu, Cr, As and Zn

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Pedersen, Anne Juul; Christensen, Iben Vernegren

    2005-01-01

    , that the charcoal contained a high concentration of Zn, probably from paint. Chemical extraction experiments in HNO were conducted with the charcoal and it was found that the order of extraction (in percentage) was Zn > Cu > As > Cr. A SEM/EDX investigation of the mixed ash from combustion showed the presence...... of small particles with wood structure with elevated Cu and Cr concentrations, but most particles were irregular shaped matrix particles rich in Si, Al and K. Cr was abundant in many different particles including the lignin skeleton of the small, unburned wood pieces, but also inside silica-based matrix...... form in a small layer on the surface of some matrix particles indicating condensation of volatile Cu species. Chemical extraction with inorganic acids showed the order of percentages mobilized as: As > Cu > Cr....

  16. Relation Between pH and Desorption of Cu, Cr, Zn, and Pb from Industrially Polluted Soils

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Hansen, Henrik K.; Jensen, Pernille Erland

    2009-01-01

    Desorption of Cu, Cr, Pb, and Zn from industrially polluted soils as a result of acidification is in focus. The eight soils of the investigation vary greatly in composition and heavy metal concentration/combination. Three soils had elevated concentrations of Cu, Pb, and Zn; regardless of pollution...... level, pollution origin, and soil type, the order for desorption as pH decreased was Zn > Cu > Pb. Turning to a single heavy metal in different soils, there was a huge difference in the pH at which the major desorption started. The variation was most significant for Pb where, e.g., less than 10......% was desorbed at pH 2.5 from one soil, whereas in another soil 60% Pb was desorbed at this pH. Sequential extraction was made and the soils in which a high percentage of Pb was found in the residual phase (adsorbed strongest) was also the soils where less Pb was desorbed at low pH in the desorption experiments...

  17. Electronic structure of metastable bcc Cu-Cr alloy thin films: Comparison of electron energy-loss spectroscopy and first-principles calculations.

    Science.gov (United States)

    Liebscher, C H; Freysoldt, C; Dennenwaldt, T; Harzer, T P; Dehm, G

    2016-07-12

    Metastable Cu-Cr alloy thin films with nominal thickness of 300nm and composition of Cu67Cr33 (at%) are obtained by co-evaporation using molecular beam epitaxy. The microstructure, chemical phase separation and electronic structure are investigated by transmission electron microscopy (TEM). The thin film adopts the body-centered cubic crystal structure and consists of columnar grains with ~50nm diameter. Aberration-corrected scanning TEM in combination with energy dispersive X-ray spectroscopy confirms compositional fluctuations within the grains. Cu- and Cr-rich domains with composition of Cu85Cr15 (at%) and Cu42Cr58 (at%) and domain size of 1-5nm are observed. The alignment of the interface between the Cu- and Cr-rich domains shows a preference for {110}-type habit plane. The electronic structure of the Cu-Cr thin films is investigated by electron energy loss spectroscopy (EELS) and is contrasted to an fcc-Cu reference sample. The experimental EEL spectra are compared to spectra computed by density functional theory. The main differences between bcc-and fcc-Cu are related to differences in van Hove singularities in the electron density of states. In Cu-Cr solid solutions with bcc crystal structure a single peak after the L3-edge, corresponding to a van Hove singularity at the N-point of the first Brillouin zone is observed. Spectra computed for pure bcc-Cu and random Cu-Cr solid solutions with 10at% Cr confirm the experimental observations. The calculated spectrum for a perfect Cu50Cr50 (at%) random structure shows a shift in the van Hove singularity towards higher energy by developing a Cu-Cr d-band that lies between the delocalized d-bands of Cu and Cr.

  18. Determination of Cr, Cu, Fe, Ni, Pb and Zn by ICP-OES in mushroom samples from Sakarya, Turkey

    Directory of Open Access Journals (Sweden)

    Esra Altıntığ

    2017-06-01

    Full Text Available Russula cyanoxantha, Russula delica, Lactarius salmonicolor, Lactarius deliciosus, Pleurotus eryngii, Pleurotus ostreatus, Agaricus bisporus, Suillus luteus, Pleurotus spp and Boletus edulis were collected from Sakarya-Turkey respectively. Also canned food in the form of the Pleurotus eryngii, Pleurotus ostreatus, and Lactarius salmonicolor mushrooms were used for the examination. Trace metal concentrations found in these mushrooms were determined inductively using coupled plasma optic emission spectrometry microwave processes. The results were obtained for (Cr 0.3-26.65, (Cu 17.38-132.75, (Fe 26.3-225.40, (Ni 2.57-39.28, (Pb 11.52-185.20, and (Zn 22.86-126.84 mg/kg. The accuracy of the method was checked by the standard reference material; tea leaves (INCY-TL-1 and tomato leaves (1573a.

  19. Comparative assessment of the biological tolerance of chernozems in the south of Russia towards contamination with Cr, Cu, Ni, and Pb in a model experiment

    Science.gov (United States)

    Kolesnikov, S. I.; Yaroslavtsev, M. V.; Spivakova, N. A.; Kazeev, K. Sh.

    2013-02-01

    The biological properties of chernozems in the south of Russia worsen under the impact of contamination with Cr, Cu, Ni, and Pb compounds. The tolerance of chernozems towards contamination decreases in the following sequence: ordinary chernozems > typical chernozems > southern chernozems > leached vertic chernozems. This sequence is specified by the soil reaction and the organic matter content. The high humus content determines the high buffer capacity of chernozems towards contamination with chromium, whereas the high pH values ensure the soil tolerance towards contamination with copper, nickel, and lead. With respect to their adverse effect on the biological properties of the chernozems, the studied heavy metals can be arranged into the following sequence: CrO3 > CuO > PbO ≥ NiO.

  20. 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.

  1. Stress relaxation study of water atomized Cu-Cr-Zr powder alloys consolidated by inverse warm extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Poblano-Salas, C.A., E-mail: carlos.poblano@ciateq.m [CIATEQ A.C., Centro de Tecnologia Avanzada, Av. Manantiales 23 A, Parque Industrial Bernardo Quintana, El Marques, Queretaro, C.P. 76246 (Mexico); Barceinas-Sanchez, J.D.O., E-mail: obarceinas@ipn.m [CICATA-IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Cerro Blanco 141, Colinas del Cimatario, Santiago de Queretaro, Queretaro, C.P. 76090 (Mexico)

    2009-10-19

    Stress relaxation testing in compression at high temperature was performed on Cu-Cr-Zr alloys produced by consolidation of water atomized powders. Precipitation and recrystallization were monitored during stress relaxation experiments carried out at an ageing temperature of 723 K. Pre-straining imposed to the Cu-Cr-Zr samples prior to stress relaxation testing resulted in reduced hardness compared to that reported for conventionally-aged alloys; it also resulted in shorter times for achieving maximum strengthening on ageing.

  2. Gas adsorption and structural diversity in a family of Cu(II) pyridyl-isophthalate metal-organic framework materials

    Science.gov (United States)

    Gould, Jamie A.; Athwal, Harprit Singh; Blake, Alexander J.; Lewis, William; Hubberstey, Peter; Champness, Neil R.; Schröder, Martin

    2017-01-01

    A family of Cu(II)-based metal-organic frameworks (MOFs) has been synthesized using three pyridyl-isophthalate ligands, H2L1 (4'-(pyridin-4-yl)biphenyl-3,5-dicarboxylic acid), H2L2 (4''-(pyridin-4-yl)-1,1':4',1''-terphenyl-3,5-dicarboxylic acid) and H2L3 (5-[4-(pyridin-4-yl)naphthalen-1-yl]benzene-1,3-dicarboxylic acid). Although in each case the pyridyl-isophthalate ligands adopt the same pseudo-octahedral [Cu2(O2CR)4N2] paddlewheel coordination modes, the resulting frameworks are structurally diverse, particularly in the case of the complex of Cu(II) with H2L3, which leads to three distinct supramolecular isomers, each derived from Kagomé and square nets. In contrast to [Cu(L2)] and the isomers of [Cu(L3)], [Cu(L1)] exhibits permanent porosity. Thus, the gas adsorption properties of [Cu(L1)] were investigated with N2, CO2 and H2, and the material exhibits an isosteric heat of adsorption competitive with leading MOF sorbents for CO2. [Cu(L1)] displays high H2 adsorption, with the density in the pores approaching that of liquid H2. This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'.

  3. Simulation of Cu-Mg metallic glass: Thermodynamics and structure

    DEFF Research Database (Denmark)

    Bailey, Nicholas; Schiøtz, Jakob; Jacobsen, Karsten Wedel

    2004-01-01

    We have obtained effective medium theory interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced low-temperature configurations by cooling from...

  4. EPR Study of Cr5+ and Cu2+ in Some Zeolites Introduced by Solid- and Liquid-State Reactions

    Science.gov (United States)

    Köksal, Fevzi; Ucun, Fatih; Kartal, İbrahim

    1996-04-01

    This study reports on the EPR of Cr5+ and Cu2+ ions, introduced by solid- and liquid-state reactions with the synthetic zeolites 3A, 4A and 5A, and the natural zeolite clinoptilolite. Cr3+ was oxidized to Cr5+ in the samples, the coordination around Cr5+ being square pyramidal. Super-hyperfine (shf) interaction of Cr5+ with 27Al nucleus was observed in both solid-and liquid-state-introduced 5A zeolite, whereas this shf could not be observed for the solid-state introduced 4A zeolite. The liquid-state Cr-introduced 4A zeolite needed a heat treatment at 473 K for ½ h for the appearance of shfs. Furthermore, it has been found that the coordination structure around the Cu2+ is square pyramidal in solid-state introduced samples, whereas it is octahedral in the liquid-state introduced ones.

  5. 3D-AP and positron annihilation study of precipitation behavior in Cu-Cr-Zr alloy

    DEFF Research Database (Denmark)

    Hatakeyama, M.; Toyama, T.; Yang, J.

    2009-01-01

    Precipitation behavior in a Cu-0.78%Cr-0.13%Zr alloy during aging and reaging has been studied by laser-assisted local electrode three-dimensional atom probe (Laser-LEAP) and positron annihilation spectroscopy (PAS). After the prime aging at 460 degrees C, Cr clusters enriched with Zr were observ...

  6. Adsorption of Cu(II) and Cr(VI) ions by chitosan: Kinetics and ...

    African Journals Online (AJOL)

    drinie

    2001-01-01

    Jan 1, 2001 ... From these results it is clear that the adsorption of heavy metals is possible with chitosan, but ... Cu is ingested at high concentrations it can become toxic to ... stated that the surface charge of chitosan varies drastically as a.

  7. Potential Health Risk Assessment of Cr, Cu, Fe and Zn for Human Population via Consumption of Commercial Spices; a Case Study of Hamedan City, Iran

    Directory of Open Access Journals (Sweden)

    Sobhanardakani S.* PhD

    2016-09-01

    Full Text Available Abstract Aims: Spices are sources of many bioactive compounds that can improve the taste of food as well as affecting the digestion and metabolism. Along with that, they may also contain some substances as heavy metals, which have harmful effects on the body. The aim of present study was to assess the potential health risk of Cr, Cu, Fe and Zn contents of cardamom, curry powder and turmeric in Hamedan City, Iran. Instrument & Methods: 18 industrially packaged and weighted spice samples (cardamom, curry powder and turmeric belonging to 6 famous brands were bought from different supermarkets of Hamedan City, Iran, in 2015. The human health risks posed by chronic exposure to the heavy metals were assessed by computing the average daily intake of metal. The health risk index (HRI for the local population through the consumption of spice was assessed using DIM/RfD formula. Data were analyzed using ANOVA, DMS post-hoc, Tukey HSD and Pearson's correlation coefficient tests. Findings: Cr was detected in spice samples in 0.08-1.67mg/kg, Cu 0.05-1.28mg/kg, Fe 1.04-6.89mg/kg and Zn 0.40-2.25mg/kg. The mean concentration of Cu, Fe and Zn were lower than MPL. The DIM values for the examined spice samples were below the recommended values. Conclusion: The levels of Cr, Cu, Fe and Zn are less than the MPL in cardamom, curry powder and turmeric in Hamedan City, Iran.

  8. Geospatial Mapping of Pb, Cr, Cu, Zn, Cd, and Sb in Urban Soil, Cd. Juarez, Chihuahua, Mexico

    Science.gov (United States)

    Amaya, M. A.; Grimida, S. E.; Elkekli, A. R.; Aldouri, R. K.; Benedict, B. A.; Pingitore, N. E., Jr.

    2015-12-01

    Population-based random stratified sampling of the city of Cd. Juarez, Chihuahua, Mexico provided 500 city blocks for study. We collected soil from the public space (where present) in front of each house on a selected block; equal measured small volumes of these were combined to produce a composite sample for analysis. Such composite samples (1) decrease, by an order of magnitude, laboratory processing and analysis costs, and (2) smooth the data to represent blocks as averages of individual houses. Retention of the unanalyzed samples of the individual houses permits their later analysis should the composites suggest further study of individual houses on an anomalous block. Elemental analysis of 10 mg pressed powders was performed on a Panalytical Epsilon5 EDS-XRF, via 8 secondary targets and 12 USGS and NIST multi-element rock standards. The mean and (range) of concentration for Pb was 43 (13-550) ppm; for Cr, 31 (1.8-76); for Cu, 22 (6-550); for Zn 84 (42-415) ppm; for Cd, 1.9 (0.1-6.2); and for Sb, 5.9 (2.7-29). The old urban core of Cd. Juarez was marked by high levels of Pb, Cr, Cu, and Zn, and, to a smaller degree, of Cd and Sb. This pattern mirrors that of contiguous El Paso, Texas, USA, directly across the narrow Rio Grande. Businesses, industrial facilities, transportation (both railroads and highways), traditional "downtown" shopping, and old residential districts cluster in this urban core. A Pb-Cu-Zn smelter, which operated for more than a century until 1999, is present in the US adjacent to the Rio Grande, about two km away from downtown Cd. Juarez. Thus the city has been subject to both traditional metal sources (e.g., leaded gasoline, highway debris) and smelter emissions. The poplation of Cd. Juarez has exploded in the last few decades to some 1.5 million inhabitants due both to natural growth and in-migration from rural districts for economic opportunity. Most of this growth has been accommodated by radial expansion of the city into the surrounding

  9. Photocatalytic removal of M{sup 2+} (=Ni{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, Cd{sup 2+}, Hg{sup 2+} and Ag{sup +}) over new catalyst CuCrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ketir, W.; Bouguelia, A. [Laboratoire de Stockage et de Valorisation des energies Renouvelables, Faculty of Chemistry (USTHB), BP 32, 16111 Algiers (Algeria); Trari, M. [Laboratoire de Stockage et de Valorisation des energies Renouvelables, Faculty of Chemistry (USTHB), BP 32, 16111 Algiers (Algeria)], E-mail: mtrari@caramail.com

    2008-10-30

    The metal ions M{sup 2+} (Ni{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, Cd{sup 2+}, Hg{sup 2+} and Ag{sup +}) are potentially toxic. Their electro deposition has been carried out in aqueous air-equilibrated CuCrO{sub 2} suspension upon visible illumination. The delafossite CuCrO{sub 2} is p-type semiconductor characterized by a low band gap (1.28 eV) and a long-term chemical stability. The corrosion rate is found to be 10{sup -2} {mu}mol m{sup -2} month{sup -1} in aqua regia. The oxide has been elaborated through nitrate route where the specific surface area is increased via the surface/bulk ratio. A correlation exists between the dark M{sup 2+} adsorption, the redox potential of M{sup 2+/0} couple and the conduction band of CuCrO{sub 2} positioned at -1.06 V{sub SCE}. Ag{sup +} cannot be photoreduced because of its positive potential located far above the valence band. By contrast, Zn{sup 2+} is efficiently deposited due to the large driving force at the interface. The improved photoactivity of copper with a deposition percentage (90%) is attributed to the strong dark adsorption onto the surface catalyst. The results indicate a competitive effect with the water reduction; it has been observed that the M{sup 2+} deposition goes parallel with the hydrogen evolution. Such behavior is attributed to the low H{sub 2} over voltage when ultra fine aggregate of M islands are photodeposited onto CuCrO{sub 2} substrate.

  10. Microstructure and solidification behavior of multicomponent CoCrCu{sub x}FeMoNi high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.H. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Liu, N., E-mail: lnlynn@126.com [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Yang, W. [School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063 (China); Zhu, Z.X. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Lu, Y.P. [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, X.J. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China)

    2015-08-26

    (Fe, Co, Ni) rich dendrites nucleate primarily in CoCrFeMoNi and CoCrCu{sub 0.1}FeMoNi alloys, followed by peritetic and eutectic reactions. The quasi-peritectic reaction occurs between the primary Mo-rich dendrites and liquids in the CoCrCu{sub 0.3}FeMoNi melts, and transfers to a eutectic coupled-growth at the edge of the quasi-peritectic structure. Subsequently, eutectic reaction happens in the remnant liquids. Liquid-phase separations have occurred in CoCrCu{sub x}FeMoNi alloys when x≥0.5. Meanwhile, some nanoscale precipitates are obtained in the Cu-rich region. Two crystal structures, FCC and BCC, are identified in CoCrCu{sub x}FeMoNi high entropy alloys. Amazingly, a pretty high plastic strain (51.6%) is achieved in CoCrCu{sub 0.1}FeMoNi alloy when the compressive strength reaches to 3012 Mpa. With the increase of Cu content, atomic size difference (ΔR) and electro-negativity difference (ΔX) decrease while valence electron concentration (VEC), mixing enthalpy (ΔH) and mixing entropy (ΔS) increase. Consequently, the valence electron concentration (VEC) values range for the formation of mixture of FCC and BCC structures can be enlarged to 6.87–8.35 based on the study of this paper. It is the positive enthalpies of mixing that causes the liquid-phase separation in CoCrCu{sub x}FeMoNi high entropy alloys.

  11. Texture Analysis of Cu-Cr-Zr Alloy in Process of Deformation%Cu-Cr-Zr系合金变形过程中的织构分析

    Institute of Scientific and Technical Information of China (English)

    朱永兵; 慕思国; 李华清; 郭富安

    2009-01-01

    The Cu-Cr-Zr alloy was treated by hot rolling, solution and cold rolling. The types and the evolution of texture in the different state were investigated using X-ray diffraction. The results show that the main solution and the cube texture disappears. In the condition of cold rolling, the intensity of texture enhances with the increasing of the deformation. The main textures during the cold rolling are C, B and S texture. In the early stage of the cold rolling, it appears the%对Cu-Cr-Zr系合金铸锭进行热轧、固溶和冷轧,利用X射线衍射仪测试合金材料不同状态下的织构,分析各个状态下的织构种类及其演变规律.结果表明:热轧后材料中主要织构为Copper{112}〈111〉(C)织构、Brass{011}〈211〉(B)织构和S{123}〈634〉织构,存在微弱的立方织构{001}〈100〉;固溶后材料中织构的强度降低,立方织构消失;冷轧后材料中织构的强度随着变形量的增加而强度增加,冷轧过程中主要织构也是C织构、B织构和S织构,在冷轧初期出现Goss{011}〈100〉(G)织构,随后G织构慢慢减弱,直至消失.

  12. Optimization of Heat Treatment of CuNiSiCrRE Alloy%CuNiSiCrRE合金热处理工艺的优化

    Institute of Scientific and Technical Information of China (English)

    郭宇航; 支海军; 吕秀芬; 师学礼

    2011-01-01

    By means of Brinell hardness tester and eddy-current conductometer as well as SEM, the effects of solid solution temperature, aging and cold deforming before aging on microstructure and properties of the CuNiSiCrRE alloy were studied, then the optimum heat treatment was detennined The results show that the optimized heat treatment process was solution at 900 ℃ for 1. 5 h with cooling in water, 40% cold-working and aging at 480 ℃ for 2 h with cooling in air. The hardness was 229 HB, electrical conductivity was 45. 6%IACS, tensile strength reached 674 MPa, yield strength was 641 MPa, elongation was 16 % and softening temperature was 540 ℃. Tensile fracture was ductile fracture.%采用布氏硬度计、涡流导电仪和扫描电子显微镜等研究了固溶温度、时效及时效前冷变形量对CuNiSiCrRE合金显微组织和性能的影响,在此基础上确定了其最佳热处理工艺.结果表明:该合金的最佳热处理工艺为900℃×1.5h固溶水冷+40%的冷变形+480℃×2h时效空冷,其相应的硬度为229HB,电导率为45.6%lACS,抗拉强度为674MPa,屈服强度为641MPa,伸长率为16%,软化温度为540℃,拉伸断口为韧性断裂.

  13. Comparing the Pressure-Induced Structural Behavior of CuCr 2 O 4 and CuCr 2 Se 4 Spinels

    Energy Technology Data Exchange (ETDEWEB)

    Efthimiopoulos, I. [Department; Deutsches GeoForschungsZentrum (GFZ), Section 4.3,; Tsurkan, V. [Institute; Experimental; Loidl, A. [Experimental; Zhang, Dongzhou [Partnership; Wang, Y. [Department

    2017-07-20

    We have conducted high-pressure measurements on the CuCr2O4 and CuCr2Se4 spinels to unravel the structural systematics of these materials under compression. Our studies have revealed diverse structural behavior in these two compounds. In particular, CuCr2O4 retains its ambient-pressure I41/amd structure up to 50 GPa. Close inspection of the lattice and interatomic parameters reveals a compressibility change near 23 GPa, which is accompanied by an expansion of the apical Cr–O bond distances. We speculate that an outer Cr3+ 3d orbital reorientation might be at play in this system, manifesting as the change in compressibility at that pressure point. On the other hand, CuCr2Se4 undergoes a structural transformation from the starting Fd3¯m phase toward a monoclinic structure initiated at ~8 GPa and completed at ~20 GPa. This high-pressure behavior resembles that of ZnCr2Se4, and it appears that, unlike similar chalcogenide Cr spinels, steric effects take a leading role in this pressure-induced Fd3¯m → monoclinic transition. Close comparison of our results with the reported literature yields significant insights behind the pressure-induced structural systematics of this important family of materials, thus both allowing for the careful manipulation of the structural/physical properties of these systems by strain and promoting our understanding of similar pressure-induced effects in relevant systems.

  14. The crystal structure of Cu9.1(1)TeSb3, a stuffed derivative of Cr3Si

    DEFF Research Database (Denmark)

    Søtofte, Inger; Makovicky, E.; Karup-Møller, Sven

    1998-01-01

    The intermetallic compound Cu9.1(1)TeSb3 prepared at 973 K is an ordered member of the solid solution Cu64Te31Sb5-Cu70Te8Sb22 which also exists, for more limited composition ranges, between 673 K and 1173 K. It is a stuffed derivative of the structure type A15 (Cr3Si). Te is surrounded by twelve ...

  15. Hydrogen photo-evolution over the spinel CuCr{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Boumaza, Souhila [Laboratoire de Chimie de Gaz Naturel, USTHB, BP 32 16111 Algiers (Algeria); Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (C.R.A.P.C) BP248 Algiers RP, 16004 (Algeria); Bouarab, Rabah [Laboratoire de Chimie de Gaz Naturel, USTHB, BP 32 16111 Algiers (Algeria); Trari, Mohamed; Bouguelia, Aissa [Laboratoire de Stockage et de Valorisation des Energies Renouvelables, Faculte de Chimie, USTHB, BP 32 Bab Ezzouar, 16111 Algiers (Algeria)

    2009-01-15

    The photocatalytic H{sub 2} evolution over CuCr{sub 2}O{sub 4} has been studied in connection with some physical properties. The black oxide is classified as a narrow band gap semiconductor crystallizing in the normal spinel structure. The photoactivity is dependent on the preparative conditions through the surface area of the powder and CuCr{sub 2}O{sub 4} has been synthesized by nitrate route. The conductivity varies exponentially with temperature indicating an extrinsic conductivity between mixed valences states Cr{sup 3+/4+} located in octahedra sharing common corners. The oxide exhibits p-type conductivity with an activation energy of 0.20 eV and a hole mobility of 2.14 x 10{sup -8} cm{sup 2}/V s thermally activated. CuCr{sub 2}O{sub 4} shows an excellent chemical stability, a corrosion potential of -0.775 V{sub SCE} and an exchange current density of 16 {mu}A cm{sup -2} have been determined from the semilogarithm plot. The capacitance measurement (C{sup -2}-V), performed in basic electrolyte, exhibits a linear behavior from which a flat band potential of 0.48 V{sub SCE} was obtained. CuCr{sub 2}O{sub 4} is photoelectrochemically stable by hole consumption reactions involving X{sup 2-} (=SO{sub 3}{sup 2-} and S{sub 2} O{sub 3}{sup 2-}) as hole scavengers. The best catalytic performance for H{sub 2}-photoproduction was obtained in (NaOH 0.5 M, Na{sub 2}S{sub 2}O{sub 3} 0.025 M) with an average rate of 0.013 cm{sup 3} h{sup -1} (mg catalyst){sup -1} and a quantum efficiency of 0.2% under polychromatic light. S{sub 2} O{sub 3}{sup 2-} is oxidized to SO{sub 3}{sup 2-} and subsequently to SO{sub 4}{sup 2-} as proven by the dual slopes in the Tafel plot. The system shows a tendency towards saturation whose deceleration is the result of the competitive reductions of the end products namely S{sub 2} O{sub 6}{sup 2-} and S{sub 2} O{sub 4}{sup 2-} with the water discharge. (author)

  16. Preparation of CuCrO2-WO3 and its photocatalytic performance for hydrogen production%CuCrO2-WO3的制备及光催化产氢性能

    Institute of Scientific and Technical Information of China (English)

    王桂赟; 刘先平; 赵茜; 王延吉; 林瑞榕

    2014-01-01

    The principle of p-n type semiconductor composite photocatalysts is discussed as a strategy to develop efficient photocatalysts for water splitting. Composite of p-type and n-type semiconductor has an advantage in taking full use of each semiconductor’s function of oxidation and reduction, which could facilitate the photo-induced electron/hole pairs’ separation by the inner electric field, enhancing the photocatalytic efficiency of the system. CuCrO2 was synthesized by a novel combustion reaction method with glycerin as fuel, and WO3 was prepared by the tungsten acid decomposition method. The configurations CuCrO2-WO3 and Ru/(CuCrO2-WO3) were successfully prepared by mechanical grinding and heat-treatment. The prepared samples were characterized by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance (UV-vis DR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of CuCrO2, WO3, CuCrO2-WO3 and Ru/(CuCrO2-WO3) were evaluated under xenon lamp irradiation. The factors including pH of grinding media and Ru loading were also investigated. When glycerin was used as the sacrificial reagent under xenon lamp irradiation, CuCrO2 or WO3 powders alone was not able to catalyze H2 generation from water splitting, while coupled photocatalysts of CuCrO2-WO3 displayed remarkable photocatalytic activity. The improvement of photocatalytic activity was attributed to the formation of p-n junctures at the interface of CuCrO2-WO3. When grinding media was at pH 8, dispersion of WO3 was particularly better, which contributed to more efficient compounding of the two powders and better activity of the composite as a consequence. Ru loading as cocatalyst also remarkably enhanced photocatalytic hydrogen production. The 0.5% (mass) Ru/(CuCrO2-WO3) exhibited better photocatalytic activity for splitting pure water into hydrogen under 300W xenon lamp irradiation, on which H2 production was about 10μmol for 3 h.%作

  17. Manufacturing and High Heat Flux Testing of Brazed Flat-Type W/CuCrZr Plasma Facing Components

    Science.gov (United States)

    Lian, Youyun; Liu, Xiang; Feng, Fan; Chen, Lei; Cheng, Zhengkui; Wang, Jin; Chen, Jiming

    2016-02-01

    Water-cooled flat-type W/CuCrZr plasma facing components with an interlayer of oxygen-free copper (OFC) have been developed by using vacuum brazing route. The OFC layer for the accommodation of thermal stresses was cast onto the surface of W at a temperature range of 1150 °C-1200 °C in a vacuum furnace. The W/OFC cast tiles were vacuum brazed to a CuCrZr heat sink at 940 °C using the silver-free filler material CuMnSiCr. The microstructure, bonding strength, and high heat flux properties of the brazed W/CuCrZr joint samples were investigated. The W/Cu joint exhibits an average tensile strength of 134 MPa, which is about the same strength as pure annealed copper. High heat flux tests were performed in the electron beam facility EMS-60. Experimental results indicated that the brazed W/CuCrZr mock-up experienced screening tests of up to 15 MW/m2 and cyclic tests of 9 MW/m2 for 1000 cycles without visible damage. supported by National Natural Science Foundation of China (No. 11205049) and the National Magnetic Confinement Fusion Science Program of China (No. 2011GB110004)

  18. Itinerant magnetism in metallic CuFe2Ge2.

    Science.gov (United States)

    Shanavas, K V; Singh, David J

    2015-01-01

    Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF) at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. These results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  19. Design of Cu8Zr5-based bulk metallic glasses

    DEFF Research Database (Denmark)

    Yang, L.; Xia, J.H.; Wang, Q.;

    2006-01-01

    Basic polyhedral clusters have been derived from intermetallic compounds at near-eutectic composition by considering a dense packing and random arrangement of atoms at shell sites. Using such building units, bulk metallic glasses can be formed. This strategy was verified in the Cu-Zr binary syste.......382)(100-x)Nb-x, where x=1.5 and 2.5 at. %, and (Cu0.618Zr0.382)(98)Sn-2. The present results may open a route to prepare amorphous alloys with improved glass forming ability....

  20. Sensitive determinations of Cu, Pb, Cd, and Cr elements in aqueous solutions using chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Yang, X Y; Hao, Z Q; Li, C M; Li, J M; Yi, R X; Shen, M; Li, K H; Guo, L B; Li, X Y; Lu, Y F; Zeng, X Y

    2016-06-13

    In this study, chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy (CR-SENLIBS) was for the first time applied to improve the detection sensitivities of trace heavy metal elements in aqueous solutions. Utilizing chemical replacement effect, heavy metal ions in aqueous solution were enriched on the magnesium alloy surface as a solid replacement layer through reacting with the high chemical activity metallic magnesium (Mg) within 1 minute. Unitary and mixed solutions with Cu, Pb, Cd, and Cr elements were prepared to construct calibration curves, respectively. The CR-SENLIBS showed a much better detection sensitivity and accuracy for both unitary and mixed solutions. The coefficients of determination R2 of the calibration curves were above 0.96, and the LoDs were of the same order of magnitude, i.e., in the range of 0.016-0.386 μg/mL for the unitary solution, and in the range of 0.025-0.420 μg/mL for the mixed solution. These results show that CR-SENLIBS is a feasible method for improving the detection sensitivity of trace element in liquid sample, which definitely provides a way for wider application of LIBS in water quality monitoring.

  1. The effect of different crystal conditions of filler metal on vacuum brazing of TiAl alloy and 42CrMo

    Institute of Scientific and Technical Information of China (English)

    Zhu Ying; Zhang Mo; Wang Guojian; Li Wenyi; Kang Hui; Qu Ping

    2007-01-01

    Ti-based filler metals made by transient solidification and normal crystallization were selected for the vacuum brazing of the TiAl alloy and 42CrMo under different processing parameters. The results show that the tensile strength of the joint of transient solidified filler metal is higher than that of normal crystallized filler metal under the same processing parameters. By the analysis of scanning electron microscope(SEM) and X-ray diffracting (XRD) , it is found that the higher strength maybe caused by the generating of TiAl , TiNi and TiCu at the interface of joint made by transient solidified filler metal.

  2. Cr(VI) removal from aqueous solution by thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1 in the presence of single and multiple heavy metals.

    Science.gov (United States)

    Li, Han; Huang, Shaobin; Zhang, Yongqing

    2016-09-01

    Cr(VI) pollution is increasing continuously as a result of ongoing industrialization. In this study, we investigated the thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1, isolated from the biofilm of a biotrickling filter used in nitrogen oxides (NOX) removal, with respect to its ability to remove Cr(VI) from an aqueous solution. TAD1 was capable of reducing Cr(VI) from an initial concentration of 10 mg/L to non-detectable levels over a pH range of 7-9 and at a temperature range of 30-50°C. TAD1 simultaneously removed both Cr(VI) and NO3 (-)-N at 50°C, when the pH was 7 and the initial Cr(VI) concentration was 15 mg/L. The reduction of Cr(VI) to Cr(III) correlated with the growth metabolic activity of TAD1. The presence of other heavy metals (Cu, Zn, and Ni) inhibited the ability of TAD1 to remove Cr(VI). The metals each individually inhibited Cr(VI) removal, and the extent of inhibition increased in a cooperative manner in the presence of a combination of the metals. The addition of biodegradable cellulose acetate microspheres (an adsorption material) weakened the toxicity of the heavy metals; in their presence, the Cr(VI) removal efficiency returned to a high level. The feasibility and applicability of simultaneous nitrate removal and Cr(VI) reduction by strain TAD1 is promising, and may be an effective biological method for the clean-up of wastewater.

  3. 爆炸焊接对 ITER 级 CuCrZr 合金性能的影响%Effect of explosive welding on properties of lTER-grade CuCrZr alloy

    Institute of Scientific and Technical Information of China (English)

    马锐; 王耀华; 吴继红; 谌继明

    2015-01-01

    To study the effect of explosive welding on the properties of ITER-grade CuCrZr alloy,the differ-ent solution annealing (SA)processes were used to make explosive welding CuCrZr/31 6L (N)panel for international thermonuclear experimental reactor (ITER )firstwall (FM) module.Optical microscopy (OM),scanning electron microscopy (SEM)and transmission electron microscope (TEM)were utilized to analyze the microstructure of CuCrZr alloy through the whole process.Its hardness and tensile property were tested and evaluated.With reference to Gerold,the tensile strength increment scope of CuCrZr alloy was calculated at the over-aging state.According to the results,SA treatment can effectively repair the structure deformation of CuCrZr alloy caused by explosive blast.After SA (980 ℃,30 min)and hot iso-static pressing (HIP)(580 ℃,145 MPa,2 h)treatments,the CuCrZr side of joint will be finely undula-ted with the hardness of 120 HV and the tensile strength of 380 MPa.The CuCrZr alloy has isoaxial crystal structure in side,with fine and uniform crystalline grains whose average size is 98 μm,and meets the inter-national thermonuclear experimental reactor(ITER)standard in term of the overall performance indexes.%为了研究爆炸焊接对 ITER 级 CuCrZr 合金性能的影响,针对爆炸焊接法制备的 ITER 屏蔽包层第一壁模块 CuCrZr/316L(N)复合板,采用不同的固溶工艺进行处理。综合利用光学显微镜、场扫描电子显微镜和透射电镜,对整个工艺过程中 CuCrZr 合金的微观结构进行观察与分析,测试并评估了 CuCrZr 合金的硬度和拉伸性能。结合 Gerold 公式,计算了过时效状态下 CuCrZr 合金抗拉强度增量的范围。结果表明,固溶处理可以有效修复因爆炸荷载冲击造成的合金组织变形,经过固溶(980℃,30 min)和热等静压(580℃,145 MPa,2 h)处理后,结合界面 CuCrZr 一侧的硬度达到120 HV,抗拉强度大于380 MPa,显微组织呈现晶粒均匀细小等轴晶组

  4. Separation of Cu2+, Cd2+ and Cr3+ in a Mixture Solution Using a Novel Carrier Poly(Methyl Thiazoleethyl Eugenoxy Acetate) with BLM (Bulk Liquid Membrane)

    Science.gov (United States)

    Djunaidi, M. C.; Khabibi; Ulumudin, I.

    2017-02-01

    The separation process using a novel carrier polyeugenol has active groups N and S has been done with the technique BLM. Polyeugenol has groups active N and S was synthesized from eugenol which is then polymerized into polyeugenol. This polymeric compounds was then acidified become acidic poly (eugenoksi acetate). After the acid formed, then the synthesis was continued by add 4-methyl-5-tiazoleetanol to form esters poly (methyl thiazole eugenoxy ethyl acetate) (PMTEEA). The result of the synthesis was analyzed by FTIR and 1H NMR. This polyester product synthesis was applied as a carrier for separating metal ions Cu2+, Cd2+ and Cr3+ with variations in feed phase pH = 5 and pH = 7 in the membrane of chloroform using techniques BLM. Receiving phase after 24 hours was analyzed by AAS. In variations of feed pH = 5 ions was obtained 66.21% Cd2+, 28.83% Cu2+ and 10.92% of Cr3+, at pH = 7 was obtained 70.77% Cd2+, 30.14% Cu2+, and 3.72% of Cr3+.

  5. Antibacterial property of CuCrO{sub 2} nanopowders prepared by a self-combustion glycine nitrate process

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-15

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

  6. Ultrasonic spray-pyrolyzed CuCrO2 thin films

    Science.gov (United States)

    Sánchez-Alarcón, R. I.; Oropeza-Rosario, G.; Gutierrez-Villalobos, A.; Muro-López, M. A.; Martínez-Martínez, R.; Zaleta-Alejandre, E.; Falcony, C.; Alarcón-Flores, G.; Fragoso, R.; Hernández-Silva, O.; Perez-Cappe, E.; Mosqueda Laffita, Yodalgis; Aguilar-Frutis, M.

    2016-05-01

    In this paper the optical, structural and electrical properties of CuCrO2 thin films deposited by ultrasonic spray pyrolysis at temperatures from 400 to 600 °C in steps of 50 °C are presented. Copper and chromium acetylacetonates were chosen as sources of Cu and Cr, respectively, and N,N-dimethylformamide was used as the solvent. X-ray results confirmed that the films as deposited showed the CuCrO2 phase without any post-deposition thermal annealing. The surface morphology was observed to be mirror like, and as the films were deposited at different temperatures, they gradually revealed the presence of small crystallites. The best film’s optical percentage transmission (in the visible region), about 58%, was obtained in films deposited at 450 °C, and the highest band gap energy (3.17 eV) was measured in films deposited at 400 °C. The electrical properties of the films were obtained by the Hall effect. A hole concentration in the range 1019-1021 cm-3, conductivity as high as 35 S cm-1, and mobility lower than 1 cm2 V-1 s-1 were obtained in the films. p-type conductivity was confirmed using the hot point probe arrangement, and the Seebeck coefficient was estimated. The hole conductivity is thought to be due to excess oxygen in the films. Finally, the minimum energy required to transfer carriers from acceptor level to the valence band in the films was estimated by impedance spectroscopy.

  7. Cu2+、Cd2+和Cr6+对孔雀鱼的单一与联合毒性效应%Single and joint toxicity of Cu2+,Cd2+ and Cr6+ on Poecilia reticulata

    Institute of Scientific and Technical Information of China (English)

    赵岩; 孔强; 付荣恕

    2009-01-01

    采用静水生物测试法研究了Cu、Cd和Cr等重金属对孔雀鱼的单一与联合毒性效应.单一毒性试验结果表明:暴露时间为24,48,72和96 h时,Cu2+对孔雀鱼的LC50分别为5.70,4.02,2.95和2.36 mg/L,Cd2+对孔雀鱼的LC50分别为23.24,20.15,18.07和17.71 mg/L,Cr6+对孔雀鱼的LC50分别为88.56,65.21,47.81和43.40 mg/L.3种重金属离子对孔雀鱼均为高毒性,毒性大小为Cu2+>Cd2+>Cr6+.联合毒性试验表明:当浓度比为1:1或1:1:1,Cu2+与Cd2+、Cu2+与Cr6+、Cd2+与Cr6+以及Cu2+、Cd2+与Cr6+共存时的联合毒性均为毒性增强的协同作用.

  8. Transient Liquid Phase Bonding of Cu-Cr-Zr-Ti Alloy Using Ni and Mn Coatings: Microstructural Evolution and Mechanical Properties

    Science.gov (United States)

    Venkateswaran, T.; Ravi, K. R.; Sivakumar, D.; Pant, Bhanu; Janaki Ram, G. D.

    2017-08-01

    High-strength copper alloys are used extensively in the regenerative cooling parts of aerospace structures. Transient liquid phase (TLP) bonding of a Cu-Cr-Zr-Ti alloy was attempted in the present study using thin layers of elemental Ni and Mn coatings applied by electroplating. One of the base metals was given a Ni coating of 4 µm followed by a Mn coating of 15 µm, while the other base metal was given only the Ni coating (4 µm). The bonding cycle consisted of the following: TLP stage—heating to 1030 °C and holding for 15 min; homogenization stage—furnace cooling to 880 °C and holding for 2 h followed by argon quenching to room temperature. Detailed microscopy and electron probe microanalysis analysis of the brazed joints were carried out. The braze metal was found to undergo isothermal solidification within the 15 min of holding time at 1030 °C. At the end of TLP stage, the braze metal showed a composition of Cu-17Ni-9Mn (wt.%) at the center of the joint with a steep gradient in Ni and Mn concentrations from the center of the braze metal to the base metal interfaces. After holding for 2 h at 880 °C (homogenization stage), the compositional gradients were found to flatten significantly and the braze metal was found to develop a homogeneous composition of Cu-11Ni-7Mn (wt.%) at the center of the joint. In lap-shear tests, failures were always found to occur in the base metal away from the brazed region. The copper alloy base metal was found to undergo significant grain coarsening due to high-temperature exposure during brazing and, consequently, suffer considerable reduction in yield strength.

  9. Overview spectra and axial distribution of spectral line intensities in a high-current vacuum arc with CuCr electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lisnyak, M.; Pipa, A. V.; Gorchakov, S., E-mail: gorchakov@inp-greifswald.de, E-mail: weltmann@inp-greifswald.de; Iseni, S.; Franke, St.; Khapour, A.; Methling, R.; Weltmann, K.-D., E-mail: gorchakov@inp-greifswald.de, E-mail: weltmann@inp-greifswald.de [Leibniz-Institut für Plasmaforschung und Technologie e.V., Felix-Hausdorff-Straße 2, 17489 Greifswald (Germany)

    2015-09-28

    Spectroscopic investigations of free-burning vacuum arcs in diffuse mode with CuCr electrodes are presented. The experimental conditions of the investigated arc correspond to the typical system for vacuum circuit breakers. Spectra of six species Cu I, Cu II, Cu III, Cr I, Cr II, and Cr III have been analyzed in the wavelength range 350–810 nm. The axial intensity distributions were found to be strongly dependent on the ionization stage of radiating species. Emission distributions of Cr II and Cu II can be distinguished as well as the distributions of Cr III and Cu III. Information on the axial distribution was used to identify the spectra and for identification of overlapping spectral lines. The overview spectra and some spectral windows recorded with high resolution are presented. Analysis of axial distributions of emitted light, which originates from different ionization states, is presented and discussed.

  10. Regressional modeling of electrodialytic removal of Cu, Cr and As from CCA treated timber waste

    DEFF Research Database (Denmark)

    Moreira, E.E.; Ribeiro, Alexandra B.; Mateus, Eduardo;

    2005-01-01

    Waste of wood treated with chromated copper arsenate (CCA) is expected to increase in volume over the next decades. Alternative disposal options to landfilling are becoming more attractive to study, especially those that promote re-use. The authors have studied and modeled the electrodialytic (ED......) removal of Cu, Cr and As from CCA treated timber waste. The method uses a low-level direct current as the cleaning agent, combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in eight experiments using a laboratory cell on sawdust...

  11. Oxidation Control and Non-equilibrium Phase Formation in Cu-Cr Alloys during Mechanical Alloying

    Institute of Scientific and Technical Information of China (English)

    Xiaolong CUI; Lai WANG; Min QI

    2001-01-01

    Using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and optical microscopy, phase transformation of Cu-Cr alloys with various compositions during mechanical alloying process has been investigated. Besides the formation of supersaturated solid solution, the results show that a kind of amorphous oxide formed in the process,and the addition of carbon has obviously effect on the suppression of oxidation and the deoxidization of oxide. The reactive milling has a remarkable effect on the behavior of oxidation.

  12. STUDY ON THE HOT DEFORMATION BEHAVIORS OF Al-Zn-Mg-Cu-Cr ALUMINUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    G.Y. Lin; Z.F. Zhang; H. Zhang; D.S. Peng; J. Zhou

    2008-01-01

    The hot deformation behaviors and mierostructures of Al-Zn-Mg-Cu-Cr aluminum alloy have been studied using thermal simulation test, optical microscopy and transmission electron microscopy. As a result, the true stress versus true strain curves and the microstructures under various deformation conditions are obtained. The microstructures gradually incline to dynamic-recrystallization with the deformation temperature rising and the recrystallization grains refine with the decrease of deformation temperature or with raising the strain rates. The quantitative relationship between the Zener-HoUomon parameter (Z) and average recrystallization grain size in the subsequent heat treatment is set up.

  13. Nanostructured Cu-Cr alloy with high strength and electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Islamgaliev, R. K., E-mail: saturn@mail.rb.ru; Nesterov, K. M. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa 450000 (Russian Federation); Bourgon, J.; Champion, Y. [ICMPE-CNRS, Université Paris 12, 6-8 rue Henri Dunant, 94320 Thiais, cedex (France); Valiev, R. Z. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa 450000 (Russian Federation); Laboratory for Mechanics of Bulk Nanostructured Materials, Saint Petersburg State University, 198504 Peterhof, Saint Petersburg (Russian Federation)

    2014-05-21

    The influence of nanostructuring by high pressure torsion (HPT) on strength and electrical conductivity in the Cu-Cr alloy has been investigated. Microstructure of HPT samples was studied by transmission electron microscopy with special attention on precipitation of small chromium particles after various treatments. Effect of dynamic precipitation leading to enhancement of strength and electrical conductivity was observed. It is shown that nanostructuring leads to combination of high ultimate tensile strength of 790–840 MPa, enhanced electrical conductivity of 81%–85% IACS and thermal stability up to 500 °C. The contributions of grain refinement and precipitation to enhanced properties of nanostructured alloy are discussed.

  14. Epitaxial Cu(001) films grown on a Cr/Ag/Fe/GaAs(001) buffer system

    Energy Technology Data Exchange (ETDEWEB)

    Gottlob, Daniel M., E-mail: d.gottlob@fz-juelich.de [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Fakultät für Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, 47048 Duisburg (Germany); Jansen, Thomas [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Jülich-Aachen Research Alliance, Fundamentals for Future Information Technology (JARA-FIT), Forschungszentrum Jülich, 52425 Jülich (Germany); Hoppe, Michael [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Bürgler, Daniel E. [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Jülich-Aachen Research Alliance, Fundamentals for Future Information Technology (JARA-FIT), Forschungszentrum Jülich, 52425 Jülich (Germany); and others

    2014-07-01

    We present a procedure to prepare single-crystalline, high-purity Cu(001) films (templates) suitable as substrates for subsequent epitaxial thin-film growth. The template films were grown in a dedicated molecular-beam epitaxy system on a Cr/Ag/Fe/GaAs(001) buffer layer system. Low-energy electron diffraction and X-ray diffraction were applied to determine the surface orientation and the epitaxial relationship between all layers of the stack. Post-annealing at moderate temperatures enhances the quality of the film as shown by low-energy electron diffraction and atomic force microscopy. X-ray photoemission and Auger electron spectroscopy confirm that no atoms of the buffer layers diffuse into the Cu film during the initial preparation and the post-annealing treatment. The completed Cu(001) template system can be exposed to air and afterwards refurbished by Ar{sup +}-ion bombardment and annealing, enabling the transfer between vacuum systems. The procedure provides suitable conductive thin film templates for studies of epitaxial thin films, e.g. on the magnetic and magnetotransport properties of Co and Ni based films and multilayers. - Highlights: • Preparation of epitaxial Cu(001) template films on an insulating substrate • Characterization of template structure, orientation, cleanness, and roughness • Template films can be exposed to air and refurbished in different vacuum system. • Template films are suitable for further thin film growth at up to 570 K.

  15. Strengthening effect of Cu-rich phase precipitation in 18Cr9Ni3CuNbN austenitic heat-resisting steel

    Institute of Scientific and Technical Information of China (English)

    Chengyu CHI; Hongyao YU; Jianxin DONG; Xishan XIE; Zhengqiang CUI; Xiaofang CHEN; Fusheng LIN

    2011-01-01

    The Cu-containing austenitic heat-resistant steel 18Cr9Ni3CuNbN, which is being used as superheater and reheater tube material for modern ultra-super-critical (USC) power plants all over the world, has been investigated at 650 ℃ long time aging till 10 000 h. SEM, TEM and 3DAP (three dimensional atom probe) have been used to follow microstructural changes with mechanical property variations. Experimental results show that Cu-rich phase and MX precipitate in the grains as well as M23C6 precipitates at grain boundaries are the main precipitation strengthening phases in this steel. Among them Cu-rich phase is the most important strengthening phase. Homogeneous distribution of very fine nano-size Cu-rich phase has been formed at very early stage of 650℃ aging (less than 1 h). Cu atoms gradually concentrate to Cu-rich particles and the other elements (such as Fe, Cr, Ni etc) diffuse away from Curich particles to γ-matrix with the increasing of aging time at 650 ℃. The growth rate of Cu-rich phase at 650 ℃ long time aging is very slow and the average diameters of Cu-rich phase have been determined by TEM method. Cu-rich phase keeps in about 30 nm till 650℃ aging for 10 000 h. It shows that nano-size Cu-rich phase precipitation strengthening can be kept for long time aging at 650 ℃ because of its excellent stability at high temperatures. According to structure stability study and mechanical properties determination results the Cu-rich phase precipitation sequence and its strengthening mechanism model have been suggested and discussed.

  16. Cu-Cr-Nb-Zr Alloy for Rocket Engines and Other High-Heat- Flux Applications

    Science.gov (United States)

    Ellis, David L.

    2013-01-01

    Rocket-engine main combustion chamber liners are used to contain the burning of fuel and oxidizer and provide a stream of high-velocity gas for propulsion. The liners in engines such as the Space Shuttle Main Engine are regeneratively cooled by flowing fuel, e.g., cryogenic hydrogen, through cooling channels in the back side of the liner. The heat gained by the liner from the flame and compression of the gas in the throat section is transferred to the fuel by the liner. As a result, the liner must either have a very high thermal conductivity or a very high operating temperature. In addition to the large heat flux (>10 MW/sq m), the liners experience a very large thermal gradient, typically more than 500 C over 1 mm. The gradient produces thermally induced stresses and strains that cause low cycle fatigue (LCF). Typically, a liner will experience a strain differential in excess of 1% between the cooling channel and the hot wall. Each time the engine is fired, the liner undergoes an LCF cycle. The number of cycles can be as few as one for an expendable booster engine, to as many as several thousand for a reusable launch vehicle or reaction control system. Finally, the liners undergo creep and a form of mechanical degradation called thermal ratcheting that results in the bowing out of the cooling channel into the combustion chamber, and eventual failure of the liner. GRCop-84, a Cu-Cr-Nb alloy, is generally recognized as the best liner material available at the time of this reporting. The alloy consists of 14% Cr2Nb precipitates in a pure copper matrix. Through experimental work, it has been established that the Zr will not participate in the formation of Laves phase precipitates with Cr and Nb, but will instead react with Cu to form the desired Cu-Zr compounds. It is believed that significant improvements in the mechanical properties of GRCop-84 will be realized by adding Zr. The innovation is a Cu-Cr-Nb-Zr alloy covering the composition range of 0.8 to 8.1 weight

  17. Phase transition in nonmagnetic Al-doped delafossite oxide CuCrO{sub 2}: Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.R.; Qin, M.H., E-mail: qinmh@scnu.edu.cn

    2015-10-09

    In this work, the effects of the lattice defects and random exchange interaction on the phase transition in the classical frustrated spin model (Lin et al., 2014) [14] are investigated by Monte Carlo simulation in order to study the nonmagnetic Al doping effect in CuCrO{sub 2}. It is observed that the long range magnetic order can be significantly suppressed by the lattice defects and random exchange induced by the Al substitution, qualitatively consistent with experimental observation. Thus, both the lattice defects and random exchange are confirmed to be responsible for the variation of the transition temperature of CuCr{sub 1−x}Al{sub x}O{sub 2} with x. - Highlights: • Al doping effect on phase transition in CuCrO{sub 2} is studied by Monte Carlo simulation of a classical Heisenberg model. • Both the lattice defects and random exchange contribute to the variation of the transition temperature of CuCr{sub 1−x}Al{sub x}O{sub 2} with x. • The effect of the lattice defects is proved to be dominant in the Al doping effect in CuCrO{sub 2}.

  18. Pure CuCr2O4 nanoparticles: Synthesis, characterization and their morphological and size effects on the catalytic thermal decomposition of ammonium perchlorate

    Science.gov (United States)

    Hosseini, Seyed Ghorban; Abazari, Reza; Gavi, Azam

    2014-11-01

    In the present paper a pure phase of the copper chromite spinel nanoparticles (CuCr2O4 SNPs) were synthesized via the sol-gel route using citric acid as a complexing agent. Then, the CuCr2O4 SNPs has been characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In the next step, with the addition of Cu-Cr-O nanoparticles (NPs), the effects of different parameters such as Cu-Cr-O particle size and the Cu/Cr molar ratios on the thermal behavior of Cu-Cr-O NPs + AP (ammonium perchlorate) mixtures were investigated. As such, the catalytic effect of the Cu-Cr-O NPs for thermal decomposition of AP was evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA/DSC results showed that the samples with different morphologies exhibited different catalytic activity in different stages of thermal decomposition of AP. Also, in the presence of Cu-Cr-O nanocatalysts, all of the exothermic peaks of AP shifted to a lower temperature, indicating the thermal decomposition of AP was enhanced. Moreover, the heat released (ΔH) in the presence of Cu-Cr-O nanocatalysts was increased to 1490 J g-1.

  19. Origen y comportamiento de Cd, Cr, Cu, Pb y Zn en el subsistema acuífero de la Plana de Castellón

    Directory of Open Access Journals (Sweden)

    Morell, I.

    1996-12-01

    Full Text Available A study on Cd, Cr, Cu, Pb and Zn concentrations in Castellón Plain aquifer has been carried out in order to know if the industrial activity of this zone affects to the groundwater quality. Adsorption processes and relative migration velocity of these metals through the soils of this zone have also been studied. Metal concentrations in the aquifer are lower than those expected in an area with an intense industrial activity. It can be due to the fact that these metals show high adsorption coefficients in the soils and very low migration velocities through them, so it is no probable that the metals from the waste-waters reach the aquifer, or they take some time to reach it.En el presente trabajo se estudia la concentración de Cd, Cr, Cu, Pb y Zn en el acuífero de la Plana de Castellón, para conocer si la actividad industrial de la zona afecta a la calidad de las aguas subterráneas. Asimismo se estudian los procesos de adsorción y velocidad de migración de dichos metales en suelos de la zona. Las concentraciones de metales en el acuífero son más bajas de lo que cabría esperar, dada la intensa actividad industrial de la zona. Ello puede ser debido a que, dado que los metales presentan altos coeficientes de adsorción en los suelos y una velocidad de migración a través de los mismos muy reducida, no parece probable que dichos elementos procedentes de vertidos de aguas residuales lleguen a alcanzar el acuífero, o, en todo caso, tardarán muchos años en hacerlo, ya que el suelo actúa reteniéndolos y retrasando su llegada al mismo.

  20. Elastic properties of fcc Fe-Mn-X (X = Cr, Co, Ni, Cu) alloys studied by the combinatorial thin film approach and ab initio calculations.

    Science.gov (United States)

    Reeh, S; Kasprzak, M; Klusmann, C D; Stalf, F; Music, D; Ekholm, M; Abrikosov, I A; Schneider, J M

    2013-06-19

    The elastic properties of fcc Fe-Mn-X (X = Cr, Co, Ni, Cu) alloys with additions of up to 8 at.% X were studied by combinatorial thin film growth and characterization and by ab initio calculations using the disordered local moments (DLM) approach. The lattice parameter and Young's modulus values change only marginally with X. The calculations and experiments are in good agreement. We demonstrate that the elastic properties of transition metal alloyed Fe-Mn can be predicted by the DLM model.

  1. The structure, Raman spectroscopy and evidence of ferromagnetic transition in CuCr{sub 1−x}M{sub x}O{sub 2} (M=Mn and Rh) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Elkhouni, T., E-mail: elkhouni@yahoo.fr [Laboratoire des Sciences des Matériaux et d’Environnement, Université de Sfax, Faculté des Sciences de Sfax, BP 802, 3018 Sfax (Tunisia); Amami, M. [Laboratoire des Sciences des Matériaux et d’Environnement, Université de Sfax, Faculté des Sciences de Sfax, BP 802, 3018 Sfax (Tunisia); Unité de Recherche de Chimie des Matériaux, ISSBAT, Université Tunis ElManar, 9, Avenue Dr. Zouhaier Safi, 1006 Tunis (Tunisia); Colin, C.V.; Strobel, P. [Institut Néel, CNRS et Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9 (France); Ben Salah, A. [Laboratoire des Sciences des Matériaux et d’Environnement, Université de Sfax, Faculté des Sciences de Sfax, BP 802, 3018 Sfax (Tunisia)

    2014-04-15

    The CuCr{sub 1−x}M{sub x}O{sub 2} (M=Mn, Rh) polycrystalline powders were synthesized by the direct solid state reaction of Cu{sub 2}O and M{sub 2}O{sub 3} (M=trivalent cation or mixer of trivalent cation for transition metal). The magnetic susceptibility was measured in the temperature range of 0–300 K. It was found that the magnetic susceptibility (χ) increases rapidly with the doping of Cr{sup 3+} by Mn{sup 3+} and Rh{sup 3+} ions with existence of paramagnetic substance at low temperature. With the substitution of magnetic Mn{sup 3+} and Rh{sup 3+} for Cr{sup 3+} (S=3/2), the antiferromagnetic (AF) transition becomes broader and the transition temperature increases. However, at low temperature, the magnetic data for CuCr{sub 1−x}M{sub x}O{sub 2} (M=Mn, Rh) show evidence for weak ferromagnetic (FM) transition between 100 K and 130 K. Clear hysteresis loops indicate that FM order exists in both of them Mn or Rh-doped samples at 4 K. All samples behave like semiconductors. The ferromagnetism properties can be attributed to the double exchange interaction between the Mn{sup 3+} or Rh{sup 3+} and Cr{sup 3+} semiconductors compounds. - Highlights: • Mn replacement of the Cr in the magnetic frustrated CuCrO{sub 2}. • Mn{sup 3+}/Mn{sup 4+} generate anisotropic microstrains in the structure. • Mn substitutions lead to an increase of the susceptibilities magnetic. • The incorporation of Mn{sup 3+}/Mn{sup 4+} in CuCrO{sub 2} induced weak ferromagnetic interactions at low temperature.

  2. Structure and properties of FeCoNiCrCu0.5Alx high-entropy alloy%FeCoNiCrCu0.5Alx高熵合金的结构和性能

    Institute of Scientific and Technical Information of China (English)

    李宝玉; 彭坤; 胡爱平; 周灵平; 朱家俊; 李德意

    2013-01-01

    Effects of Al content and heat treatment on the structure,hardness and electrochemical properties of FeCoNiCrCu0.5Alx high-entropy alloys were investigated.The phase structure of as-cast alloys evolves from FCC phase to BCC phase with the increase of Al content.The stable phase of FeCoNiCrCu0.5Alx high-entropy alloys will transform from FCC phase to FCC+BCC duplex phases when x value increases from 0.5 to 1.5.The hardness of BCC phase is higher than that of FCC phase,and the corrosion resistance of BCC phase is better than FCC phase in chlorine ion and acid medium.High hardness and good corrosion resistance can be obtained in as-cast FeCoNiCrCu05Al1.0 alloy.%研究Al含量和热处理对FeCoNiCrCu0.5Alx多主元高熵合金的相结构、硬度和电化学性能的影响规律.随着Al含量的增加,铸态合金的相结构由FCC相向BCC相转变.当x从0.5增加到1.5时,FeCoNiCrCu0.5Alx高熵合金的稳定结构由FCC结构向FCC+BCC双相结构转变.BCC相的硬度高于FCC相的,在氯离子及酸性介质中BCC相的耐腐蚀性均优于FCC相的.FeCoNiCrCu0.5Al1.0铸态合金具有高硬度和良好的抗腐蚀性能.

  3. Slurry Erosion Behavior of Destabilized and Deep Cryogenically Treated Cr-Mn-Cu White Cast Irons

    Directory of Open Access Journals (Sweden)

    S. Gupta

    2016-12-01

    Full Text Available The effects of destabilization treatment and destabilization followed by cryogenic treatment have been evaluated on the microstructural evolution and sand-water slurry erosion behavior of Cr-Mn-Cu white cast irons. The phase transformations after the destabilization and cryotreatment have been characterized by bulk hardness measurement, optical and scanning electron microscopy, x-ray diffraction analysis. The static corrosion rate has been measured in tap water (with pH=7 and the erosion-corrosion behavior has been studied by slurry pot tester using sand-water slurry. The test results indicate that the cryogenic treatment has a significant effect in minimizing the as-cast retained austenite content and transforming into martensitic and bainitic matrix embedded with ultra-fine M7C3 alloy carbides. In contrast, by conventional destabilization treatment retained austenite in the matrix are not fully eliminated. The slurry erosive wear resistance has been compared with reference to destabilized and cryotreated high chromium iron samples which are commonly employed for such applications. The cryotreated Cr-Mn-Cu irons have exhibited a comparable erosive wear performance to those of high chromium irons. Higher hardness combined with improved corrosion resistance result in better slurry erosion resistance.

  4. Dynamic recrystallization behavior and processing map of the Cu-Cr-Zr-Nd alloy.

    Science.gov (United States)

    Zhang, Yi; Sun, Huili; Volinsky, Alex A; Tian, Baohong; Song, Kexing; Chai, Zhe; Liu, Ping; Liu, Yong

    2016-01-01

    Hot deformation behavior of the Cu-Cr-Zr-Nd alloy was studied by hot compressive tests in the temperature range of 650-950 °C and the strain rate range of 0.001-10 s(-1) using Gleeble-1500D thermo-mechanical simulator. The results showed that the flow stress is strongly dependent on the deformation temperature and the strain rate. With the increase of temperature or the decrease of strain rate, the flow stress significantly decreases. Hot activation energy of the alloy is about 404.84 kJ/mol and the constitutive equation of the alloy based on the hyperbolic-sine equation was established. Based on the dynamic material model, the processing map was established to optimize the deformation parameters. The optimal processing parameters for the Cu-Cr-Zr-Nd alloy hot working are in the temperature range of 900-950 °C and strain rate range of 0.1-1 s(-1). A full dynamic recrystallization structure with fine and homogeneous grain size can be obtained at optimal processing conditions. The microstructure of specimens deformed at different conditions was analyzed and connected with the processing map. The surface fracture was observed to identify instability conditions.

  5. Resistance behaviour and interdiffusion of layered CuNi-NiCr films

    Energy Technology Data Exchange (ETDEWEB)

    Brueckner, W. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Schumann, J. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Baunack, S. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Pitschke, W. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Knuth, T. [Microtech GmbH, Teltow (Germany)

    1995-03-15

    On the basis of sputtered NiCr/CuNi/NiCr triple layers and multilayers, investigations of the electrical resistance R and its temperature coefficient TCR, as well as of the concentration depth profiles and of the temperature dependence of the lattice parameter have been carried out to study the influences of the interfaces in the as-deposited state as well as annealed ones. Furthermore, the temperature dependence of the film stress has been considered. As to the resistance, the influence of the diffusion zone can be described by a parallel resistor R{sub i} having {Delta}TCR{sub i}. These quantities are dependent on both deposition and annealing and were determined for the two configurations on silicon wafers in the as-deposited state as well as in the 300 C annealed one. The AES investigations show distinct interdiffusion effects after annealing above 300 C. The Ni impoverishment observed in the CuNi results in a lattice parameter decrease. The film stress is only slightly influenced by interfacial effects. ((orig.))

  6. Electrodialytic Remediation of Soil Slurry-Removal of Cu, Cr, and As

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Jensen, Pernille Erland; Hansen, Henrik K.

    2009-01-01

    formed particles that were cementing soil minerals together. The soil was suspended in distilled water, distilled water with I2 crystals to have an oxidizing environment, or in an acidified environment at pH about 1.0. The experiments lasted from 1 to 3 weeks. Good results were obtained in two...... experiments; an experiment where the soil was suspended in distilled water and the remediation lasted 3 weeks with 2.5 mA and an experiment with acidification of the soil suspension with HNO3 to pH about 1.0 (2 weeks and 5 mA). The best separation of pollutants and soil was obtained in the experiment......Severe soil contamination is often found at old wood preservation sites and a common combination of pollutants is Cu, Cr, and As. In the present work it is tested if simultaneous removal of Cu, Cr, and As can be obtained in an electrodialytic cell where the polluted soil is remediated as a stirred...

  7. Synthesis of metallic glasses and metallic glass based composites in the Cu-Mo-Hf system by ion beam mixing

    Institute of Scientific and Technical Information of China (English)

    BAI Xue; WANG TongLe; CUI YuanYuan; DING Ning; LI JiaHao; LIU BaiXin

    2012-01-01

    Single-phase and dual-phase metallic glasses as well as metallic glass based composites were synthesized in the Cu-Mo-Hf ternary metal system by 200 keV xenon ion beam mixing of far-from-equilibrium.It was found that Mo-Hf-based and Cu-Mo-based single-phase metallic glasses could be obtained at compositions around Cu17Mo20Hf63 and Cu34Mo57Hf9,respectively.Interestingly,at the nearly equal-atomic stoichiometry of Cu38Mo31Hf31,a dual-phase Cu-Mo-Hf metallic glass,consisting both of the Mo-Hf-based and Cu-Mo-based phases,was first obtained at relatively low irradiation doses ranging from (1-5)×1015 Xe+/cm2,and a single-phase metallic glass was eventually obtained at a dose of 7×1015 Xe+/cm2.In addition,two glass-based composites were obtained at the compositions of Cu14Mo62Hf24 and Cu77Mo14Hf9,and they consisted of the Mo-Hf based and Cu-Mo based metallic glasses,dissolved with some uniformly distributed BCC Mo-based and FCC Cu-based crystalline solid solutions,respectively.The formation mechanism of the above described non-equilibrium alloy phases was also discussed in terms of the atomic collision theory.

  8. Structures,properties and responses to heat treatment of deformation processed Cu-15%Cr composite powders prepared by mechanical milling

    Institute of Scientific and Technical Information of China (English)

    刘京雷; 刘祖岩; 王尔德; 线恒泽

    2002-01-01

    Cu-15%Cr composite powders were produced from elemental powders by mechanical milling technique. The structures, properties and thermal stability of the composite powders were characterized by scanning and transmission electron microscopy (SEM and TEM, respectively), electron probe microanalysis(EPMA), X-ray diffractometry and microhardness testing. The results show that powders are first flattened into thin discs at the initial stage of milling and then evolved into spheroid on further milling. Lamellar structure in powders is produced after intermediate milling. The Cr laminas degenerate into particles uniformizing in Cu matrix with excessive milling. The microhardness values and internal strain sharply increase with increasing milling time. Nano-sized Cu grains were found by TEM analysis. The microstructural observations suggested that the composite powders have high thermal stability and both spherodisation and thermal grooving contribute to the instability of Cr laminas.

  9. Metal organic framework MIL-101(Cr) for dehydration reactions

    Indian Academy of Sciences (India)

    M Suresh; B David Raju; K S Rama Rao; K Raveendranath Reddy; M Lakshmi Kantam; Pavuluri Srinivasu

    2014-03-01

    Porous chromium terephthalate MIL-101 (Cr-MIL-101) has been prepared by direct method under hydrothermal conditions and characterized using X-ray diffraction, N2 sorption, TGA and FT-IR. The nitrogen adsorption-desorption isotherm shows that the Cr-MIL-101 possesses BET specific surface area of 2563 m2/g. Catalytic performance of Cr-MIL-101 in the dehydration of 1,4-butanediol and 1-phenylethanol is assessed under vapour phase conditions in the temperature range of 513-533 K and time on stream (TOS) at 513 K. Cr-MIL-101 demonstrates superior catalytic activity with conversion of 95% of 1-phenylethanol. Moreover, high surface area and nanocages with coordinated unsaturated sites of Cr-MIL-101 have allowed us to attain higher dehydrated products selectivity than Cr-supported activated carbon (Cr/AC), amberlyst-15 and HZSM-5 catalysts.

  10. Lattice dynamics and thermal transport in multiferroic CuCrO2

    Science.gov (United States)

    Bansal, Dipanshu; Niedziela, Jennifer L.; May, Andrew F.; Said, Ayman; Ehlers, Georg; Abernathy, Douglas L.; Huq, Ashfia; Kirkham, Melanie; Zhou, Haidong; Delaire, Olivier

    2017-02-01

    Inelastic neutron and x-ray scattering measurements of phonons and spin waves were performed in the delafossite compound CuCrO2 over a wide range of temperature, and complemented with first-principles lattice dynamics simulations. The phonon dispersions and density of states are well reproduced by our density functional calculations, and reveal a strong anisotropy of Cu vibrations, which exhibit low-frequency modes of large amplitude parallel to the basal plane of the layered delafossite structure. The low frequency in-plane modes also show a systematic temperature dependence of neutron and x-ray scattering intensities. In addition, we find that spin fluctuations persist above 300 K, far above the Néel temperature for long-range antiferromagnetic order, TN≃24 K . Our modeling of the thermal conductivity, based on our phonon measurements and simulations, reveals a significant anisotropy and indicates that spin fluctuations above TN constitute an important source of phonon scattering, considerably suppressing the thermal conductivity compared to that of the isostructural but nonmagnetic compound CuAlO2.

  11. Effect of vacuum heat treatment on microstructure and microhardness of cold sprayed Cu-4Cr-2Nb alloy coating

    Institute of Scientific and Technical Information of China (English)

    LI Wen-ya; GUO Xue-ping; L. DEMBINSKI; LIAO Han-lin; C.CODDET

    2006-01-01

    The effect of vacuum heat treatment on the microstructure and microhardness of cold-sprayed Cu-4%Cr-2%Nb alloy coating was investigated. The heat treatment was conducted under the temperatures from 250 ℃ to 950 ℃ with a step of 100 ℃ for 2 h. It was found that a dense thick Cu-4Cr-2Nb coating could be formed by cold spraying. After heat treatment,a Cr2Nb phase was uniformly distributed in the matrix,which was transferred from the gas-atomized feedstock. A little grain growth of Cr2Nb phase was observed accompanying with the healing-up of the incomplete interfaces between the deposited particles at the elevated temperatures. The coating microhardness increases a little with increasing the temperature to 350 ℃,and then decreases with further increasing temperature up to 950 ℃. This fact can be attributed to the microstructure evolution during the heat treatment.

  12. Effect of sintering on the relative density of Cr-coated diamond/Cu composites prepared by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Wei Cui; Hui Xu; Jian-hao Chen; Shu-bin Ren; Xin-bo He; Xuan-hui Qu

    2016-01-01

    Cr-coated diamond/Cu composites were prepared by spark plasma sintering. The effects of sintering pressure, sintering tempera-ture, sintering duration, and Cu powder particle size on the relative density and thermal conductivity of the composites were investigated in this paper. The influence of these parameters on the properties and microstructures of the composites was also discussed. The results show that the relative density of Cr-coated diamond/Cu reaches ~100% when the composite is gradually compressed to 30 MPa during the heating process. The densification temperature increases from 880 to 915°C when the diamond content is increased from 45vol% to 60vol%. The densification temperature does not increase further when the content reaches 65vol%. Cu powder particles in larger size are beneficial for in-creasing the relative density of the composite.

  13. Effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy

    Indian Academy of Sciences (India)

    G Durashevich; V Cvetkovski; V Jovanovich

    2002-02-01

    The CuCrZr alloy undergoes processes of precipitation during ageing. Besides precipitation hardening the strength is affected by cold deformation which is performed before and after ageing. The cold deformation (1) before ageing accelerates the process of strength hardening, since it induces higher rate of precipitation from the saturated -solid solution. Cold deformation (2) after ageing primarily affects the alloy strength. In this paper the results of the effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy are presented. The aim of the paper was to evaluate the most suitable combination of thermomechanical treatment and alloy properties.

  14. Kinetic sorption modelling of Cu, Ni, Zn, Pb and Cr ions to pine bark and blast furnace slag by using batch experiments.

    Science.gov (United States)

    Nehrenheim, E; Gustafsson, J P

    2008-04-01

    Storm water and landfill leachate can both contain significant amounts of toxic metals such as Zn, Cu, Pb, Cr and Ni. Pine bark and blast furnace slag are both residual waste products that have shown a large potential for metal removal from contaminated water. There are however many variables that must be optimized in order to achieve efficient metal retention. One of these variables is the time of which the solution is in contact with each unit of filter material. Metal sorption was studied in two laboratory experiments to improve the knowledge of the effects of contact time. The results showed that pine bark was generally more efficient than blast furnace slag when the metal concentrations were relatively small, whereas blast furnace slag sorbed most metals to a larger extent at increased metal loads. In addition, sorption to blast furnace slag was found to be faster than metal binding to pine bark. A pseudo-second-order kinetic model was able to describe the data well within 1000 s of reaction time.

  15. Effects of tree vegetation and waste amendments on the fractionation of Cr, Cu, Ni, Pb and Zn in polluted mine soils.

    Science.gov (United States)

    Asensio, Verónica; Vega, Flora A; Singh, Bal Ram; Covelo, Emma F

    2013-01-15

    Soils at a depleted copper mine in Touro (Galicia, Spain) are physically and chemically degraded and have also polluted the surrounding area. Due to these environmental problems and the large area of these mine soils, the reclamation strategies carried out at Touro have consisted of planting trees (pine or eucalyptus), amending with waste material (sewage sludge and paper mill residues), or using both treatments. Tree planting has been carried out for 21 years and waste amending for 10. Two different zones were selected in the mine (the settling pond and mine tailing) in order to evaluate the effect of the different reclamation practices on the chemical fractions of Cr, Cu, Ni, Pb and Zn. The results showed that soils in the untreated sites were polluted by Cr and Cu. Planting pines and eucalyptus on mine soils decreased the concentration of these heavy metals in non-mobile soil fractions. Amendments also attenuated pollution by Cr and Cu as the wastes that were used had lower concentrations than the untreated mine soils. Planting trees increased Ni, Pb and Zn retention in the non-mobile fractions, preventing them from being leached into surrounding areas. However, caution should be exercised when adding organic wastes, as they can lead to increase concentrations of Ni, Pb and Zn and their phytoavailable form. The results also showed that changes in the chemical fractionation of heavy metals in soils was more influenced by the clay percentage and both dissolved and soil organic carbon (SOC and DOC) than by soil pH or cation exchange capacity. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Surface half-metallicity of half-Heusler compound FeCrSe and interface half-metallicity of FeCrSe/GaP

    Science.gov (United States)

    Khalaf Al-zyadi, Jabbar M.; Jolan, Mudhahir H.; Yao, Kai-Lun

    2016-04-01

    Recent studies showed that half-Heusler FeCrSe exhibits half-metallic ferromagnetism (Huang et al. [20]). In this paper, we investigate extensively the electronic, magnetic, and half-metallic properties of the half-Heusler alloy FeCrSe (111) and (001) surfaces and the interface with GaP (111) substrate by using the first-principles calculations within the density functional theory. The atomic density of states demonstrates that the half-me tallicity verified in the bulk FeCrSe is maintained at the CrSe-terminated (001) and Se-terminated (111) surfaces, but lost at both Cr- and Fe-terminated (111) surfaces and the Fe-terminated (001) surface. Alternatively, for the interface of FeCrSe/GaP (111), the bulk half-metallicity is destroyed at Se-P configuration while Se-Ga interface and subinterface show nearly 100% spin polarization. Moreover, the calculated interfacial adhesion energies exhibit that Se-Ga shape is more stable than the Se-P one. The calculated magnetic moments of Se, Ga at the Se-Ga (111) interface and P at the Se-P (111) interface increase with respect to the corresponding bulk values while the atomic magnetic moment of Se atom at the Se-P (111) interface decreases. We also notice that the magnetic moments of subinterface Fe at both Se-Ga and Se-P (111) interfaces decrease compared to the bulk values.

  17. Preparation, characterization and application of CuCrO2/ZnO photocatalysts for the reduction of Cr(VI).

    Science.gov (United States)

    Ketir, Wahiba; Rekhila, Gharib; Trari, Mohamed; Amrane, Abdelatif

    2012-01-01

    The delafossite CuCrO2 elaborated by sol-gel from 40 nm diameter colloid is optically active in the visible region. It is characterized physically and photoelectrochemically. The microstructure is fairly homogenous with a mean crystallite size of ca. 2 microm. The optical gap (1.30 eV), determined from the diffuse reflectance, is well suited to the sunlight spectrum. The Mott Schottky plot is characteristic of P-type conductivity with a flat band potential of -0.26 V(SCE). As application, the photoreduction of chromate is successfully achieved in air-equilibrated suspension CuCrO2/ZnO (1/1). CuCrO2 is photoactivated by visible light and the electrons in the conduction band (-1.34 V(SCE)) are injected to ZnO. In the presence of salicylic acid, a conversion of Cr(VI) to Cr(III) of 57% is obtained under optimal conditions (pH 3 at 25 degrees C, 5 x 10(-4) mol/L) because of the HCrO4- dark adsorption onto ZnO (4HCrO4- + 3C7H6O3 + 18O2 + 16H+ --> 4Cr3+ + 21CO2 + 19H2O, deltaG0 = -557 kcal/mol). Prolonged illumination is accompanied by a deceleration in the photoactivity owing to the competitive water reduction, an issue of energetic concern. The hetero-system exhibits self sensitization for hydrogen production with an evolution rate of 149 micromol/(hr x g).

  18. Preparation,characterization and application of CuCrO2/ZnO photocatalysts for the reduction of Cr(Ⅵ)

    Institute of Scientific and Technical Information of China (English)

    Wahiba Ketir; Gharib Rekhila; Mohamed Trari; Abdelatif Amrane

    2012-01-01

    The delafossite CuCrO2 elaborated by sol-gel from 40 nm diameter colloid is optically active in the visible region.It is characterized physically and photoelectrochemically.The microstructure is fairly homogenous with a mean crystallite size of ca.2 μm.The optical gap (1.30 eV),determined from the diffuse reflectance,is well suited to the sunlight spectrum.The Mott Sehottky plot is characteristic of P-type conductivity with a flat band potential of-0.26 VSCE.As application,the photoreduction of chromate is suecessfully achieved in air-equilibrated suspension CuCrO2/ZnO (1/1).CuCrO2 is photoactivated by visible light and the electrons in the conduction band (-1.34 VSCE) are injected to ZnO.In the presence of salicylic acid,a conversion of Cr(Ⅵ) to Cr(Ⅲ) of 57% is obtained under optimal conditions (pH 3 at 25℃,5×10-4 mol/L) because of the HCrO4-dark adsorption onto ZnO (4HCrO4-+ 3C7H6O3 + 18O2 + 16H+ →4Cr3+ + 21CO2 + 19H2O,△G0 =-557 kcal/mol).Prolonged illumination is accompanied by a deceleration in the photoaetivity owing to the competitive water reduction,an issue of energetic concern.The hetero-system exhibits self sensitization for hydrogen production with an evolution rate of 149 μmol/(hr·g).

  19. Estudio estructural de polvos Cu-Cr aleados mecánicamente

    Directory of Open Access Journals (Sweden)

    Aguilar, C.

    2006-10-01

    Full Text Available The changes of grain size, microstrain, stacking fault probability, stacking fault energy and dislocations density on powder mixtures of copper with 1 and 3 weight % after high energy mechanical milling. The X-ray diffraction profile was analysed by Williamson-Hall (W-H method. Grain size decreased with the increase of milling time, until values of 106 and 59 nm for 1 and 3 weight % Cr, respectively. As well microstrain increased with milling time. Stacking fault probability increased in function of milling time to value between 1x10–3–8x10–3 for Cu–1 weight % Cr and 3x10–3–8x10–3 for Cu–3 weight % Cr. The stacking fault energy decreased with milling time and amount of chromium. Finally, the dislocations density is between a range between 1x1014–1x1015 m/m3.

    El presente trabajo estudia cambios de tamaño de grano, microdeformación, probabilidad de falla de apilamiento, energía de falla de apilamiento y densidad de dislocaciones en mezclas de polvos de cobre con adición de 1 y 3% peso de cromo, sometidas a molienda mecánica de alta energía. Los perfiles de difracción de rayos X, obtenidos de las muestras, se analizaron con la metodología de Williamson-Hall (W-H. El tamaño de grano disminuyó con el incremento del tiempo de molienda, hasta valores de 106 y 59 nm para 1 y 3% peso Cr, respectivamente. A su vez los valores de microdeformación aumentaron con el tiempo de molienda. La probabilidad de falla de apilamiento, de igual forma, aumentó en función del tiempo de molienda. Se obtuvieron valores entre 1x10–3-8x10–3 para Cu-1% peso Cr y 3x10–3–8x10-3 para Cu–3% peso Cr. La energía de falla de apilamiento disminuyó en función del tiempo de molienda y porcentaje de cromo. Finalmente, los valores de densidad de dislocaciones se encuentran en un rango de 1x1014–1x1015 m/m3

  20. Itinerant magnetism in metallic CuFe2Ge2.

    Directory of Open Access Journals (Sweden)

    K V Shanavas

    Full Text Available Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. These results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  1. The duckweed Wolffia globosa as an indicator of heavy metal pollution: Sensitivity to Cr and Cd.

    Science.gov (United States)

    Grag, P; Chandra, P

    1994-01-01

    The potential of Wolffia globosa, a profusely occurring rootless duckweed, was evaluated as an indicator of metal pollution in the water bodies. Plants of W. globosa were cultured in 3% Hoagland's nutrient medium which was supplemented with 0.05, 0.1, 1.0 and 2.0 mg/L of Cr and Cd. Plants showed substantial accumulation of both the metals at lowest concentrations. For example, at 0.05 ppm, the concentration factor (Cf) value for Cr was significantly higher (5616) than for Cd (1018). A high level of tolerance was shown by the plants to both Cr and Cd. The results show that the plants are sensitive to the variations in metal concentration and are capable of high metal enrichment at very low ambient concentration of the metals. This information may be useful for detecting metals in the water.

  2. Effect of ultrasonic vibration on the dechromisation corrosion of a CuCr alloy in HCl solution

    Institute of Scientific and Technical Information of China (English)

    XU Tao; GAO Huawei; LIU Jianhua; YU Cuiyan

    2007-01-01

    The effect of ultrasonic vibration on the dechromisation corrosion of a CuCr alloy in HCl solution was studied and the corrosion mechanisms were analyzed. It is found that ultrasonic vibration reduces the dechromisation incubation time, accelerates the dechromisation corrosion rate, decreases the temperature and concentration of HCl solution, and when the dechromisation occurs it seriously weakens the microstructure of dechromisation layer. It is concluded that ultrasonic vibration can accelerate destruction of the passivation film on the Cr surface and increase the activities of Cl- and Cr.

  3. Mössbauer study of Cu0.5Fe0.5Cr2S4

    Science.gov (United States)

    Ok, Hang Nam; Baek, Kyung Seon; Lee, Heung Soo; Kim, Chul Sung

    1990-01-01

    Cu0.5Fe0.05Cr2S4 has been studied by Mössbauer spectroscopy and x-ray diffraction. The crystal structure is found to be a cubic spinel with the lattice parameter a0=9.922 Å. The temperature dependence of both the magnetic hyperfine field and magnetization is explained by the Néel theory of ferrimagnetism using three exchange integrals: JFe-Cr/kB=-13.7 K, JFe-Fe/kB=-8.3 K, and JCr-Cr/kB=8.7 K.

  4. Mechanism of laser welding on dissimilar metals between stainless steel and W-Cu alloy

    Institute of Scientific and Technical Information of China (English)

    Kai Chen; Zhiyong Wang; Rongshi Xiao; Tiechuan Zuo

    2006-01-01

    @@ CO2 laser is employed to join a piece of powder metallurgical material (PMM) to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06-0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.

  5. Influence of Al and Cu elements on the microstructure and properties of (FeCrNiCo)Al{sub x}Cu{sub y} high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Q.C., E-mail: fanqichao@126.com [Institute of Machinery Manufacturing Technology, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Li, B.S. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Y. [Institute of Machinery Manufacturing Technology, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

    2014-11-25

    Highlights: • Relationship between entropy and enthalpy on phase formation was specified. • Phase changed from fcc to fcc plus bcc and then bcc phase. • Mechanical properties changed from plasticity to brittleness. • Young’s modulus, hardness and yield strength increased with Al element. - Abstract: (FeCrNiCo)Al{sub x}Cu{sub y} high-entropy alloys were designed using the strategy of equiatomic ratio, high entropy of mixing and different mixing enthalpies of atom-pairs. The effects of entropy and enthalpy on phase forming process of the alloys were clearly studied and the influences of Al and Cu elements on the microstructure and mechanical properties were investigated. As long as Al element level increased from 0.5 to 1, the microstructure of the alloy system changed from fcc structure to duplex fcc plus bcc structure and then a single bcc structure. Increase of Al element greatly enhanced the Young’s modulus, hardness and yield strength of these alloys. (FeCrNiCo)Al{sub 0.75}Cu{sub 0.5} alloy got the most excellent comprehensive mechanical properties; its fracture strength and plastic strain were as high as 2270 MPa, and 42.70%, respectively. Cu-rich phase formed in the alloys when Cu element was in high levels. Increase of Cu element greatly decreased fracture strength of the high-entropy alloys when Al element was in the high level of x = 1.

  6. Precipitation hardening in a 12%Cr-9%Ni-4%Mo-2%Cu stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Haettestrand, Mats; Nilsson, Jan-Olof; Stiller, Krystyna; Liu Ping; Andersson, Marcus

    2004-02-23

    A combination of complementary techniques including one-dimensional and three-dimensional atom probe, energy-filtered transmission electron microscopy and conventional transmission electron microscopy has been used to assess the precipitation reactions at 475 deg. C in a 12%Cr-9%Ni-4%Mo-2%Cu precipitation hardening stainless steel. The continuous hardening up to at least 1000 h of ageing was attributed to a sequence of precipitation reactions involving nickel-rich precipitates nucleating at copper clusters followed by molybdenum-rich quasicrystalline precipitates and nickel-rich precipitates of type L1{sub 0}. An estimate of the relative contributions to the strength increment during tempering based on measurements of particle densities was performed. Nickel-rich precipitates were found to play the most important role up to about 40 h of ageing after which the effect of quasicrystalline particles became increasingly important.

  7. Fabrication of high strength conductivity submicroncrystalline Cu-5 % Cr alloy by mechanical alloying

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cu-5%Cr alloy bulk material with submicron grains were fabricated by mechanical alloying and subsequanthot hydrostatic extruaion. The micrestructure, mechanical properties and electrical conductivity of the alloy were experimentally investigated, and the influence of the extrusion temperature on its microstructure and properties was made clear.Also, the strengthening mechanism of the alloy was diacussed. It was revealed that the microstructure of the alloy is veryfine, with an average grain size being about 100 ~ 120nm, and thus possesses significant fine-grain strengthening effect,leading to very high mechanical strength of 800 ~ 1 000 MPa. Meanwhile, the alloy also possesses quite good electricalconductivity and moderate tensile elongation, with the former in the range of 55% ~ 70%(IACS) and the latter about5 % respectively.

  8. Gas sensing properties of Cu and Cr activated BST thick films

    Indian Academy of Sciences (India)

    G H Jain; L A Patil

    2006-08-01

    H2S gas sensing properties of BST ((Ba0.67Sr0.33)TiO3) thick films are reported here for the first time. BST ceramic powder was prepared by mechanochemical process. Thick films of BST were prepared by screen-printing technique. The sensing performance of the films was tested for various gases. The films were surface customized by dipping them into aqueous solutions of CuCl2 and CrO3 for various intervals of time. These surface modified BST films showed improved sensitivity to H2S gas (100 ppm) than pure BST film. Chromium oxide was observed to be a better activator than copper oxide in H2S gas sensing. The effect of microstructure and amount of activators on H2S gas sensing were discussed. The sensitivity, selectivity, stability, response and recovery time of the sensor were measured and presented.

  9. Analysis of the deformation behavior of low Cu-Cr-Zr alloy

    Science.gov (United States)

    Morozova, A.; Belyakov, A.; Kaibyshev, R.

    2016-11-01

    Mechanical properties and the microstrustural evolution of low Cu-Cr-Zr alloy subjected to equal channel angular pressing (ECAP) at 400°C via route BC after the solution treatment were investigated. Plastic deformation resulted in the formation of a large number of low-angle subgrain boundaries in initial coarse grains. New fine grains formed due to a progressive increase in misorientations of strain-induced (sub)boundaries. The ultrafine grain formation during large plastic deformation was accompanied by significant strengthening. The variation of the strain hardening rate with the flow stress after the total strain ɛ ˜ 1-12 was studied. The deformation behavior was discussed in terms of the dislocation-density-related Voce equation. Large plastic deformation led to an increase in both the ɛC and ɛV parameters in the Voce equation. The relationship between strain hardening and microstructure is considered in detail using the Voce parameters.

  10. Thermodynamic modeling of the Na-X (X = Si, Ag, Cu, Cr systems

    Directory of Open Access Journals (Sweden)

    Hao D.

    2012-01-01

    Full Text Available The Na-X (X = Si, Ag, Cu, Cr systems have been critically reviewed and modeled by means of the CALPHAD approach. The two compounds, NaSi and Ag2Na, are treated as stoichiometric ones. By means of first-principles calculations, the enthalpies of formation at 0 K for the LT-NaSi (low temperature form of NaSi and Ag2Na have been computed to be -5210 and -29821.8 Jmol-1, respectively, with the desire to assist thermodynamic modeling. One set of self-consistent thermodynamic parameters is obtained for each of these binary systems. Comparisons between calculated and measured phase diagrams show that most of the experimental information can be satisfactorily accounted for by the present thermodynamic descriptions.

  11. Atomistic simulations of Mg-Cu metallic glasses: Mechanical properties

    DEFF Research Database (Denmark)

    Bailey, Nicholas; Schiøtz, Jakob; Jacobsen, Karsten Wedel

    2004-01-01

    The atomistic mechanisms of plastic deformation in amorphous metals are far from being understood. We have derived potential parameters for molecular dynamics simulations of Mg-Cu amorphous alloys using the Effective Medium Theory. We have simulated the formation of alloys by cooling from the melt......, and have used these glassy configurations to carry out simulations of plastic deformation. These involved different compositions, temperatures (including zero), and types of deformation (uniaxial strain/pure shear), and yielded stress-strain curves and values of flow stress. Separate simulations were...

  12. The Uptake Mechanism of Cd(II, Cr(VI, Cu(II, Pb(II, and Zn(II by Mycelia and Fruiting Bodies of Galerina vittiformis

    Directory of Open Access Journals (Sweden)

    Dilna Damodaran

    2013-01-01

    Full Text Available Optimum concentrations of heavy metals like copper, cadmium, lead, chromium, and zinc in soil are essential in carrying out various cellular activities in minimum concentrations and hence help in sustaining all life forms, although higher concentration of these metals is lethal to most of the life forms. Galerina vittiformis, a macrofungus, was found to accumulate these heavy metals into its fleshy fruiting body in the order Pb(II > Cd(II > Cu(II > Zn(II > Cr(VI from 50 mg/kg soil. It possesses various ranges of potential cellular mechanisms that may be involved in detoxification of heavy metals and thus increases its tolerance to heavy metal stress, mainly by producing organic acids and phytochelatins (PCs. These components help in repairing stress damaged proteins and compartmentalisation of metals to vacuoles. The stress tolerance mechanism can be deduced by various analytical tools like SEM-EDX, FTIR, and LC-MS. Production of two kinds of phytochelatins was observed in the organism in response to metal stress.

  13. Study of the analytic quality in the determinations of Cr, Fe, Mn, Cu, Zn, Pb and Hg through conventional and nuclear analytical techniques in mosses of the MATV; Estudio de la calidad analitica en las determinaciones de Cr, Fe, Mn, Cu, Zn, Pb y Hg a traves de tecnicas analiticas nucleares y convencionales en musgos de la ZMVT

    Energy Technology Data Exchange (ETDEWEB)

    Caballero S, B.

    2013-07-01

    To evaluate the environmental risks of air pollution and to facilitate the decision-making for control, is necessary to have the capacity to generate data with analytical quality. A comparison between nuclear (Neutron activation analysis and total reflection X-ray fluorescence spectrometry) and no nuclear analytical techniques (atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry) for simultaneous determination of metal content (Cr, Cu, Fe, Hg, Mn, Pb and Zn) in mosses from Metropolitan Area of the Toluca Valley (MATV) was performed. Epiphytic mosses (Fabriona ciliaris and Leskea angustata) were sampled in two campaigns, 16 sites (urban, transition and natural) and were prepared for each technique. The biological certified reference materials were used for the quality control and to evaluate accuracy, precision, linearity, detection and quantification limits. Results show that nuclear analytical techniques and no nuclear applied in chemical analysis of Cr, Cu, Fe, Hg, Mn, Pb and Zn in moss from MATV are comparable and therefore all of these can potentially be used for this purpose. However, if its considered both, the performance parameters and economic/operational characteristics is widely recommended inductively coupled plasma optical emission spectrometry, conventional analytical technique, which showed the highest analytical grade quality. Also were observed spatial and temporal variations in the concentrations of Cr, Cu, Fe, Hg, Mn, Pb and Zn in mosses from MATV and was discussed its potential origin. The urban sites had the highest concentration of anthropogenic elements as Cr, Cu, Fe, Hg, Pb and Zn because are strongly impacted by roads with high vehicle traffic. (Author)

  14. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.

    2013-01-01

    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy

  15. Final report on in-reactor tensile tests on OFHC - Copper and CuCrZr alloy

    DEFF Research Database (Denmark)

    Singh, B.N; Edwards, D.J.; Tähtinen, S.

    2004-01-01

    of uniaxial tensile tests on pure copper and a CuCrZr alloy in a fission reactor at 363 and 393K. In the following, we first describe the experiments and then present results illustrating the build up ofstress as a function of concurrently increasing strain and displacement dose level. Results on both pre...

  16. Final report on in-reactor creep-fatigue deformation behaviour of a CuCrZr alloy: COFAT 2

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Johansen, Bjørn Sejr; Tähtinen, S.

    The main objective of the present work was to determine experimentally the mechanical response and resulting microstructural changes in CuCrZr (HT1) alloy exposed concurrently to flux of neutrons and creep-fatigue cyclic loading directly in a fission reactor. Using specially designed test...

  17. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.

    2013-01-01

    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy m

  18. Tunable Magnetic Properties in CuCr2- x Fe x O4 Ceramics by Doping of Fe

    Science.gov (United States)

    Zhu, C. M.; Wang, L. G.; Bao, D. L. G. C.; Luo, H.; Tian, Z. M.; Yuan, S. L.

    2016-08-01

    CuCr2- x Fe x O4 ceramics have been successfully synthesized using the sol-gel method for the first time. With pure formation, material structure has been characterized by x-ray diffraction. The samples have been identified as having the spinel structure with formulae CuCr2- x Fe x O4. Micrographs obtained by scanning electron microscopy show the dense microstructure of the samples. The stoichiometric ratio of the ceramics has been measured through energy dispersive spectra. Magnetic properties of CuCr2- x Fe x O4 ceramics have been discussed. Temperature dependence of magnetization presents the gradually increasing irreversible temperature as the content of Fe element increases from x = 0 to 1. Coercive field ( H C), remanent magnetization ( M r), and saturation magnetization ( M S) respectively display the monotonous variation phenomena with increasing content of Fe. The increasing M r, M S and the decreasing H C can be attributed to the change of magnetic exchange interaction because of the doped Fe. It also proves that the magnetic properties of CuCr2- x Fe x O4 ceramics can be effectively tuned by the doping content of Fe.

  19. Half metallicity in Sr{sub 2}CrOsO{sub 6} via Na doping

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Ningning [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wang, Jing [Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Wang, Ying, E-mail: ywang_2012@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wu, Zhijian, E-mail: zjwu@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2015-07-05

    Highlights: • Na-doped Sr{sub 2}CrOsO{sub 6} is investigated by using the density functional theory. • Both NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and NaSrCrOsO{sub 6} are half metals. • The Curie temperature of NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and NaSrCrOsO{sub 6} is higher than room temperature. - Abstract: The insulating Sr{sub 2}CrOsO{sub 6} has the highest Curie temperature of 725 K among the double perovskites so far. In this study, by doping with Na, NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and NaSrCrOsO{sub 6} are investigated by using the density functional theory. The calculated results indicated that the hole generated by Na goes to Os 5d t{sub 2g} orbitals. This makes one of the insulating spin channels in Sr{sub 2}CrOsO{sub 6} to be metallic in the Na-doped compounds. Thus, they become half metals. The estimated magnetic ordering temperature is 579 K for NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and 615 K for NaSrCrOsO{sub 6}, which are higher than the room temperature. Therefore, we expect that the Na-doped Sr{sub 2}CrOsO{sub 6} would be promising candidates as spintronic material.

  20. Extratores para Cd, Cu, Cr, Mn, Ni, Pb e Zn em LATOSSOLOS tratados com biossólido e cultivados com milho Extractants for Cd, Cu, Cr, Mn, Ni, Pb and Zn in biossolid-amanded Oxisols cultivated with corn

    Directory of Open Access Journals (Sweden)

    Ana Rosa Martins dos Anjos

    2001-06-01

    in agriculture needs more information on plant availability of heavy metals added to soil by this waste. The efficiency of the chemical extractants HCl 0.1 mol L-1, DTPA-TEA pH 7.3, Mehlich 3 and aqua regia for the evaluation of Cd, Cu, Cr, Mn, Ni, Pb and Zn availability in biosolid-amended soils, was studied in a pot (0.5 m³ experiment using corn as test plant. The soils used were a dystrophic Typic Hapludox (LAd and a dystrophic Rhodic Hapludox (LVd. The statistic design consisted of: random blocks in a 4x4 factorial outline, 4 treatments (LVd+sludge, LVd, LAd+sludge, LAd, 4 extraction methods (HCl 0.1 mol L-1, Mehlich 3, DTPA-TEA 0.005 mol L-1 pH 7,3 and aqua regia and 4 replications. Seventy-eight Mg ha-1 of biosolids on dry base were applied every two months to the soils, one year before planting corn. In five applications 388 Mg ha-1 of biosolids were applied. The metal contents of the various parts of the plants were correlated with the contents removed by the extraction methods. The results show that the total contents of Cr, Cu, Mn, Ni, and Zn did not exceed the critical limits established by USEPA and the European Community regulations even at the biosolid application rate of 388 Mg ha-1. Mehlich 3 was an effective extractor only in the evaluation of the bioavailability of Cu and Zn in corn grown on soils treated with biosolids. Cd, Cr, Ni and Pb presented no availability to corn plants.

  1. Concentrations of Mn, Fe, Cu, Zn, Cr, Cd, Pb, Ni in selected Nigerian tubers, legumes and cereals and estimates of the adult daily intakes.

    Science.gov (United States)

    Akinyele, I O; Shokunbi, O S

    2015-04-15

    This study was designed to determine the levels of microminerals (manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr)) and heavy metals (cadmium (Cd), lead (Pb) and nickel (Ni)) in some tubers, legumes and cereals obtained from the markets in Abeokuta city, South-West Nigeria. The food samples were digested by dry ashing procedure and their minerals were determined by atomic absorption spectrophotometer. The results show mean values of 1.67-32.00, 7.25-61.58, 1.59-10.56, 6.65-46.99, 0.02-0.58, legumes and cereals from various parts of the world. The daily intakes of the metals through tubers, legumes and cereals were found to be lower than the provisional tolerable daily intakes proposed by Joint FAO/WHO Expert Committee on Food Additives.

  2. Cr-free Co-Cu/SBA-15 catalysts for hydrogenation of biomass-derivedα-,β-unsaturated aldehyde to alcohol

    Institute of Scientific and Technical Information of China (English)

    Sanjay Srivastava; Pravakar Mohanty; Jigisha K. Parikh; Ajay K. Dalai; S. S. Amritphale; Anup K. Khare

    2015-01-01

    Cr-free bi-metallic SBA-15-supported Co–Cu catalysts were examined in the conversion of bio-mass-derived α-, β-unsaturated aldehyde (furfural) to value-added chemical furfuryl alcohol (FOL). Co–Cu/SBA-15 catalysts with a fixed Cu loading of 10 wt% and varying Co loadings (2.5, 5, and 10 wt%) were prepared by the impregnation method. The catalysts were characterized by X-ray dif-fraction, N2 sorption, H2 temperature-programmed reduction, scanning electron microscopy, ener-gy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, CO chemi-sorption, and inductively coupled plasma mass spectrometry. The influence of different reaction parameters such as temperature, pressure, catalyst dosage, and furfural concentration on the cata-lyst performance was evaluated. Relative to catalysts supported on amorphous silica, the current SBA-15-supported Co–Cu catalysts displayed higher performance, attaining a furfural conversion of 99% and furfuryl alcohol selectivity of 80%. The catalytic reactions were conducted in a 100-mL autoclave at 170 °C and 2 MPa H2 pressure for 4 h.

  3. Electronic, Magnetic, and Redox Properties of [MFe(3)S(4)] Clusters (M = Cd, Cu, Cr) in Pyrococcus furiosus Ferredoxin.

    Science.gov (United States)

    Staples, Christopher R.; Dhawan, Ish K.; Finnegan, Michael G.; Dwinell, Derek A.; Zhou, Zhi Hao; Huang, Heshu; Verhagen, Marc F. J. M.; Adams, Michael W. W.; Johnson, Michael K.

    1997-12-01

    The ground- and excited-state properties of heterometallic [CuFe(3)S(4)](2+,+), [CdFe(3)S(4)](2+,+), and [CrFe(3)S(4)](2+,+) cubane clusters assembled in Pyrococcus furiosus ferredoxin have been investigated by the combination of EPR and variable-temperature/variable-field magnetic circular dichroism (MCD) studies. The results indicate Cd(2+) incorporation into [Fe(3)S(4)](0,-) cluster fragments to yield S = 2 [CdFe(3)S(4)](2+) and S = (5)/(2) [CdFe(3)S(4)](+) clusters and Cu(+) incorporation into [Fe(3)S(4)](+,0) cluster fragments to yield S = (1)/(2) [CuFe(3)S(4)](2+) and S = 2 [CuFe(3)S(4)](+) clusters. This is the first report of the preparation of cubane type [CrFe(3)S(4)](2+,+) clusters, and the combination of EPR and MCD results indicates S = 0 and S = (3)/(2) ground states for the oxidized and reduced forms, respectively. Midpoint potentials for the [CdFe(3)S(4)](2+,+), [CrFe(3)S(4)](2+,+), and [CuFe(3)S(4)](2+,+) couples, E(m) = -470 +/- 15, -440 +/- 10, and +190 +/- 10 mV (vs NHE), respectively, were determined by EPR-monitored redox titrations or direct electrochemistry at a glassy carbon electrode. The trends in redox potential, ground-state spin, and electron delocalization of [MFe(3)S(4)](2+,+) clusters in P. furiosus ferredoxin are discussed as a function of heterometal (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Tl).

  4. Probing Pulsed Current Gas Metal Arc Welding for Modified 9Cr-1Mo Steel

    Science.gov (United States)

    Krishnan, S.; Kulkarni, D. V.; De, A.

    2015-04-01

    Modified 9Cr-1Mo steels are commonly welded using gas tungsten arc welding process for its superior control over the rate of heat input and vaporization loss of the key alloying elements although the rate electrode deposition remains restricted. Recent developments in pulsed current gas metal arc welding have significantly improved its ability to enhance the rate of electrode deposition with a controlled heat input rate while its application for welding of modified 9Cr-1Mo steels is scarce. The present work reports a detailed experimental study on the pulsed current gas metal arc welding of modified 9Cr-1Mo steels. The effect of the shielding gas, welding current, and speed on the weld bead profile, microstructure and mechanical properties are examined. The results show that the pulsed current gas metal arc welding with appropriate welding conditions can provide acceptable bead profile and mechanical properties in welds of modified 9Cr-1Mo steels.

  5. A GREEN CHEMISTRY APPROACH TO PREPARATION OF CORE (FE OR CU)-SHELL (NOBLE METALS) NANOCOMPOSITES USING AQUEOUS ASCORBIC ACID

    Science.gov (United States)

    A greener method to fabricate novel core (Fe or Cu)-shell (noble metals) nanocomposites of transition metals such as Fe and Cu and noble metals such as Au, Pt, Pd, and Ag using aqueous ascorbic acid is described. Transition metal salts such as Cu and Fe were reduced using ascor...

  6. Effects of processing parameters on the morphology, structure, and magnetic properties of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles synthesized with chemical methods

    Energy Technology Data Exchange (ETDEWEB)

    Ivantsov, R.D. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Edelman, I.S., E-mail: ise@iph.krasn.ru [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Zharkov, S.M.; Velikanov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Petrov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Ovchinnikov, S.G. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Lin, Chun-Rong [National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China); Li, Oksana [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China); Tseng, Yaw-Teng [National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China)

    2015-11-25

    Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles with x = 0, 0.2, and 0.4 were synthesized via thermal decomposition of metal nitrate or chloride salts and selenium powder using different precursor compositions and processing details. Single crystalline nano-belts or nano-rods coexist in the synthesized powder samples with hexagon-shaped plates in dependence on the precursor composition. The belts gathered into conglomerates forming “hierarchical” particles. Visible magnetic circular dichroism (MCD) of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles embedded into a transparent matrix was investigated for the first time. The similarity of the MCD spectra of all samples showed the similarity of the nanoparticles electronic structure independent of their morphology. Basing on the MCD spectral maxima characteristics, electron transitions from the ground to the excited states were identified with the help of the conventional band theory and the multi-electron approach. - Highlights: • Single crystalline Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles with x = 0, 0.2, 0.4 were synthesized. • Correlation between synthesis conditions and nanoparticles morphology were obtained. • The nanoparticles magnetization behavior was studied. • Visible MCD of the Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles were studied for the first time.

  7. Mechanical characterization and modeling of brazed tungsten and Cu-Cr-Zr alloy using stress relief interlayers

    Science.gov (United States)

    Qu, Dandan; Zhou, Zhangjian; Yum, Youngjin; Aktaa, Jarir

    2014-12-01

    A rapidly solidified foil-type Ti-Zr based amorphous filler with a melting temperature of 850 °C was used to braze tungsten to Cu-Cr-Zr alloy for water cooled divertors and plasma facing components application. Brazed joints of dissimilar materials suffer from a mismatch in coefficients of thermal expansion. In order to release the residual stress caused by the mismatch, brazed joints of tungsten and Cu-Cr-Zr alloy using different interlayers were studied. The shear strength tests of brazed W/Cu joints show that the average strength of the joint with a W70Cu30 composite plate interlayer reached 119.8 MPa, and the average strength of the joint with oxygen free high conductivity copper (OFHC Cu)/Mo multi-interlayers reached 140.8 MPa, while the joint without interlayer was only 16.6 MPa. Finite element method (FEM) has been performed to investigate the stress distribution and effect of stress relief interlayers. FEM results show that the maximum von Mises stress occurs in the tungsten/filler interface and that the filler suffers the peak residual stresses and becomes the weakest zone. And the use of OFHC Cu/Mo multi-interlayers can reduce the residual stress significantly, which agrees with the mechanical experiment data.

  8. Cu-Mn-Ni-Ag钎料高频感应钎焊2Cr13不锈钢接头的显微组织与性能%Microstructure andperformance of 2Cr13stainless steel joint by high frequency induction brazing usingCu-Mn-Ni-Agfiller alloy

    Institute of Scientific and Technical Information of China (English)

    郑义; 颜家振; 李宁; 曹永同; 帅帆

    2016-01-01

    The characteristic of Cu-Mn-Ni-Ag filler alloy and the microstructure and mechanical properties of the 2Cr13 stainless steel joint brazed by high frequency induction brazing using Cu-Mn-Ni-Ag filler alloywerestudied. The results show that the melting point of the Cu-Mn-Ni-Ag filler alloy is 880℃and it is composed of Ag-rich phase, Cu-Mn-Ni solid solution and a little Ni-Mn-Si compound; a layer of Fe-Mn-Ni-Cr-Cu solid solution forms at the interface between the filler alloy and base metal, and the brazing seam zone is composed of Ag-rich phase, Cu-Mn-Ni solid solution and a little Ni-Mn-Si compound. The brazing jointsfailsin the inside Cu-Mn-Ni solid solution and Ag-rich phase, and the fracture mode of the joints is mainly ductile dimple fracture, the best shear strength of the brazing joint at room temperature is 369 MPa, the high temperature shear strength of the brazing joints at 400℃, 500℃and 600℃are 251 MPa, 208 MPa and 84 MPa,respectively.%采用新型的Cu-Mn-Ni-Ag中温铜基钎料高频感应钎焊2Cr13不锈钢,并对钎料的工艺特性、钎焊接头的显微组织以及测试温度对钎焊接头力学性能的影响进行研究。结果表明:Cu-Mn-Ni-Ag钎料的熔点约为880℃,由富Ag相、Cu-Mn-Ni固溶体以及少量的Ni-Mn-Si化合物组成;钎料与2Cr13不锈钢产生良好的冶金结合,且钎焊接头组织致密;界面反应区的组织为Fe-Mn-Ni-Cr-Cu固溶体,钎缝区组织由富Ag相、Cu-Mn-Ni固溶体和少量的Ni-Mn-Si化合物组成;钎焊接头断裂于钎缝中间的富Ag相和CuMnNi固溶体上,为以剪切韧窝为主的韧性断裂,室温剪切强度最大可达369 MPa,在400℃、500℃和600℃下接头的剪切强度分别为251 MPa、208 MPa和84 MPa。

  9. Fingerprinting two metal contaminants in streams with Cu isotopes near the Dexing Mine, China

    Energy Technology Data Exchange (ETDEWEB)

    Song, Shiming [Chinese Geological Survey, Nanjing Center, Nanjing (China); Mathur, Ryan, E-mail: mathurr@juniata.edu [Department of Geology, Juniata College, Huntingdon, PA (United States); Ruiz, Joaquin [Department of Geosciences, University of Arizona, Tucson, AZ (United States); Chen, Dandan [Chinese Geological Survey, Nanjing Center, Nanjing (China); Allin, Nicholas [Department of Geology, Juniata College, Huntingdon, PA (United States); Guo, Kunyi; Kang, Wenkai [Chinese Geological Survey, Nanjing Center, Nanjing (China)

    2016-02-15

    Transition metal isotope signatures are becoming useful for fingerprinting sources in surface waters. This study explored the use of Cu isotope values to trace dissolved metal contaminants in stream water throughout a watershed affected by mining by-products of the Dexing Mine, the largest porphyry Cu operation in Asia. Cu isotope values of stream water were compared to potential mineral sources of Cu in the mining operation, and to proximity to the known Cu sources. The first mineral source, chalcopyrite, CuFeS{sub 2} has a ‘tight’ cluster of Cu isotope values (− 0.15‰ to + 1.65‰; + 0.37 ± 0.6‰, 1σ, n = 10), and the second mineral source, pyrite (FeS{sub 2}), has a much larger range of Cu isotope values (− 4‰ to + 11.9‰; 2.7 ± 4.3‰, 1σ, n = 16). Dissolved Cu isotope values of stream water indicated metal derived from either chalcopyrite or pyrite. Above known Cu mineralization, stream waters are approximately + 1.5‰ greater than the average chalcopyrite and are interpreted as derived from weathering of chalcopyrite. In contrast, dissolved Cu isotope values in stream water emanating from tailings piles had Cu isotope values similar to or greater than pyrite (>+6‰, a common mineral in the tailings). These values are interpreted as sourced from the tailings, even in solutions that possess significantly lower concentrations of Cu (< 0.05 ppm). Elevated Cu isotope values were also found in two soil and two tailings samples (δ{sup 65}Cu ranging between + 2 to + 5‰). These data point to the mineral pyrite in tailings as the mineral source for the elevated Cu isotope values. Therefore, Cu isotope values of waters emanating from a clearly contaminated drainage possess different Cu isotope values, permitting the discrimination of Cu derived from chalcopyrite and pyrite in solution. Data demonstrate the utility of Cu isotopic values in waters, minerals, and soils to fingerprint metallic contamination for environmental problems. - Highlights:

  10. The accumulation of heavy metals (Cd, Pb, Hg, Cr) and their state in ...

    African Journals Online (AJOL)

    ONOS

    2010-01-25

    Jan 25, 2010 ... metals (Cd, Pb, Hg and Cr) in the water and plankton of Beysehir and ... In addition, heavy metals show harmful effects ... in laboratory for a period of time for evaporation of water. ...... biochemical effects in an estuarine teleost.

  11. Effect of Element Cobalt on Microstructure and Properties of AlFeCuCrNi High Entropy Alloys%钴对AlFeCuCrNi高熵合金组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    朱海云; 孙宏飞; 高绪

    2013-01-01

    AlFeCuCrNiCo, (χ=0, 0. 5, 1. 0) high entropy alloys were prepared by vacuum arc furnace. The microstructure and phase structure change of AlFeCuCrNi alloys after addition of element cobalt were investigated by ()M, SEM, EMP, XRD and TEM. And hardness, thermal stability and corrosion resistance of these alloys were also studied. The results show the microstructure of AlFeCuCrNiCo., alloys was typically dendritic structure, the phases of these alloys consisted of simple face-centered cubic (FCC) and body-centered cubic (BCC), and adding of element cobalt reduced the lattice constants both of FCC and BCC. Compositions segregation existed in all alloys, and addition of element cobalt promoted segregation of element copper and homogenization of all the other elements. The hardness and corrosion resistance of the alloys were increased after addition of element cobalt and all alloys possessed good thermal stability.%采用真空电弧熔炼技术制备了AlFeCuCrNiCox(x=0,0.5,1.0)合金体系,通过光学显微镜、扫描电镜、电子探针、X射线衍射仪以及透射电镜研究了在AlFeCuCrNi合金中加入钴元素后显微组织及结构的变化,并对合金系的显微硬度、热稳定性及耐腐蚀性进行了研究.结果表明:AlFeCuCrNiCox(x=0,0.5,1.0)合金的显微组织均为树枝晶;合金的物相组成均为简单的体心立方和面心立方的混合结构,钴元素的加入会使合金中体心立方和面心立方的晶格常数均有所减小;所有合金均存在成分偏析现象,钴元素的加入加剧了合金中铜元素的偏析,但促进了其他元素的均匀化;钴元素的加入使合金显微硬度提高,耐腐蚀性增加;所有合金均具有较好的热稳定性.

  12. The metallomics approach: use of Fe(II) and Cu(II) footprinting to examine metal binding sites on serum albumins.

    Science.gov (United States)

    Duff, Michael R; Kumar, Challa V

    2009-11-01

    Metal binding to serum albumins is examined by oxidative protein-cleavage chemistry, and relative affinities of multiple metal ions to particular sites on these proteins were identified using a fast and reliable chemical footprinting approach. Fe(ii) and Cu(ii), for example, mediate protein cleavage at their respective binding sites on serum albumins, in the presence of hydrogen peroxide and ascorbate. This metal-mediated protein-cleavge reaction is used to evaluate the binding of metal ions, Na(+), Mg(2+), Ca(2+), Al(3+), Cr(3+), Mn(2+), Co(2+), Ni(2+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), and Ce(3+) to albumins, and the relative affinities (selectivities) of the metal ions are rapidly evaluated by examining the extent of inhibition of protein cleavage. Four distinct systems Fe(II)/BSA, Cu(II)/BSA, Fe(II)/HSA and Cu(II)/HSA are examined using the above strategy. This metallomics approach is novel, even though the cleavage of serum albumins by Fe(II)/Cu(II) has been reported previously by this laboratory and many others. The protein cleavage products were analyzed by SDS PAGE, and the intensities of the product bands quantified to evaluate the extent of inhibition of the cleavage and thereby evaluate the relative binding affinities of specific metal ions to particular sites on albumins. The data show that Co(II) and Cr(III) showed the highest degree of inhibition, across the table, followed by Mn(II) and Ce(III). Alakali metal ions and alkaline earth metal ions showed very poor affinity for these metal sites on albumins. Thus, metal binding profiles for particular sites on proteins can be obtained quickly and accurately, using the metallomics approach.

  13. Study of Metal Resistance Potential of the Cd, Cr Tolerant Alligator Weed

    Directory of Open Access Journals (Sweden)

    Suparna Pal

    2014-03-01

    Full Text Available Background – Environmental deterioration due to heavy metal pollution is a major global concern for its immense importance in the ecosystem. Indiscriminate use of heavy metals for rapid urbanization and industrial exploration is a pressing threat to human health. Among this Cd and Cr contamination is most dangerous as these metals directly enter into the food chain due to their higher solubility and mobility. Identification of a metal tolerant native plant species would be helpful to decontaminate Cd and Cr polluted land. In our previous study, field investigations were conducted to evaluate the tolerance potential of Alligator weed to Cd and Cr.Alligator weed [Alternanthera philoxeroides (Mart. Griseb ],is the most widely distributed perennial stoloniferous herb in these contaminated areas in and around Kolkata. Purpose of the study – To establish metal tolerant capacity of the species , different biochemical parameters assessing its metal accumulation capacity and reflecting its detoxification mechanism were studied. For these purpose, the same plant collected from the highest metal contaminated area was grown under laboratory condition with external application of various concentration of Cd and Cr individually and synergistically (0.5, 0.8, 1.0, 1.2, 1.5, 1.8 mM. To estimate the hazardous effects of Cd and Cr on this weed, membrane damage was quantified in form of lipid peroxidation i.e MDA production. The metal uptake and accumulation potential was estimated by measuring the Cd and Cr concentration in root and shoot. Some soil parameters such as Orgnaic Carbon, Cation exchange capacity were also studied to explain the bio availability of metals. Various biochemical parameters such as free proline content, non protein- thiol content and zymogram analysis of antioxidative isozymes (such as, Guiacol peroxidase, superoxide dismutase, glutathione reductase and ascorbate peroxidase were studied to assess its metal resistant capacity. Result

  14. Microstructural characterization of Ni-22Fe-22Cr-6Al metallic foam by transmission electron microscopy.

    Science.gov (United States)

    Kim, Hyung Giun; Lee, Taeg Woo; Lee, Jae Young; Lee, Eui Sung; Oh, Kwon Oh; Lee, Chang Woo; Lim, Sung Hwan

    2012-01-01

    Ni-22Fe-22Cr-6Al metallic foam, prepared using a thermomechanical treatment and alloying elements, was studied via transmission electron microscopy (TEM) in order to clarify the relationship between the mechanical properties and the nanoscale microstructural characteristics. Due to the unique porous structure of the metallic foam, TEM specimens were prepared using an embedding-process-assisted-ion-milling technique and a focused-ion-beam method. The Cr-, Fe- and Al-clustered regions around the surface of the metallic foam were investigated using elemental maps. The Ni(3)Al (γ') precipitates, which can affect the mechanical properties of the Ni-Fe-Cr (γ) matrix, were characterized in the metallic foam.

  15. Study of superconducting and non-superconducting (Cu, Cr)-1212 compounds by high-resolution TEM and electron energy loss spectroscopy

    CERN Document Server

    Anan, Y; Kurami, H; Hatano, J; Tsutsumi, S; Kimoto, K; Matsui, Y

    2001-01-01

    Structure of YSr/sub 2-x/Ba/sub x/Cu/sub 2.8/Cr/sub 0.2/O/sub y/ (x =0-1.5) superconductors are examined by electron diffraction, HRTEM and electron energy loss spectroscopy (EELS). YSr/sub 2/Cu/sub 2.8/Cr /sub 0.2/O/sub y/ (x=0) shows incommensurate superstructure with 3.67a/sub 0/ due to lattice strain and mixed intergrowth of -(Cr-Cu- Cu-Cu-Cr)- and -(Cr-Cu-Cu-Cr)- sequences. In the h 0 l electron diffraction pattern the wavevector [~0.27, 0, 1/2] due to the incommensurate superstructure disappear in the crystal with high Ba contain (x>or=1.0). This suggests that structural distortion decreases with Ba substitution. At the same time, Cr-L3, L2 edge of EELS spectra shifts toward the low-energy side with increase of Ba content. (13 refs).

  16. Magnetic phases of the quasi-two-dimensional antiferromagnet CuCrO2 on a triangular lattice

    Science.gov (United States)

    Sakhratov, Yu. A.; Svistov, L. E.; Kuhns, P. L.; Zhou, H. D.; Reyes, A. P.

    2016-09-01

    We have carried out Cu,6563 NMR spectra measurements in a magnetic field up to about 45 T on a single crystal of a multiferroic triangular antiferromagnet CuCrO2. The measurements were performed for magnetic fields aligned along the crystal c axis. Field and temperature evolution of the spectral shape demonstrates a number of phase transitions. It was found that the 3D magnetic ordering takes place in the low field range (H ≲15 T). At higher fields magnetic structures form within individual triangular planes whereas the spin directions of the magnetic ions from neighboring planes are not correlated. It is established that the 2D-3D transition is hysteretic in field and temperature. Line-shape analysis reveals several possible magnetic structures existing within individual planes for different phases of CuCrO2. Within certain regions on the magnetic H -T phase diagram of CuCrO2 a 3D magnetic ordering with tensor order parameter is expected.

  17. 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.

  18. Electromigration Reliability and Morphologies of Cu Pillar Flip-Chip Solder Joints with Cu Substrate Pad Metallization

    Science.gov (United States)

    Lai, Yi-Shao; Chiu, Ying-Ta; Chen, Jiunn

    2008-10-01

    The Cu pillar is a thick underbump metallurgy (UBM) structure developed to alleviate current crowding in a flip-chip solder joint under operating conditions. We present in this work an examination of the electromigration reliability and morphologies of Cu pillar flip-chip solder joints formed by joining Ti/Cu/Ni UBM with largely elongated ˜62 μm Cu onto Cu substrate pad metallization using the Sn-3Ag-0.5Cu solder alloy. Three test conditions that controlled average current densities in solder joints and ambient temperatures were considered: 10 kA/cm2 at 150°C, 10 kA/cm2 at 160°C, and 15 kA/cm2 at 125°C. Electromigration reliability of this particular solder joint turns out to be greatly enhanced compared to a conventional solder joint with a thin-film-stack UBM. Cross-sectional examinations of solder joints upon failure indicate that cracks formed in (Cu,Ni)6Sn5 or Cu6Sn5 intermetallic compounds (IMCs) near the cathode side of the solder joint. Moreover, the ~52- μm-thick Sn-Ag-Cu solder after long-term current stressing has turned into a combination of ~80% Cu-Ni-Sn IMC and ~20% Sn-rich phases, which appeared in the form of large aggregates that in general were distributed on the cathode side of the solder joint.

  19. Synthesis, characterization and photocatalytic activity of cubic-like CuCr2O4 for dye degradation under visible light irradiation

    Science.gov (United States)

    Yuan, Wenhui; Liu, Xiaoxia; Li, Li

    2014-11-01

    CuCr2O4 nanoparticles with cubic-like morphology were prepared via hydrothermal synthesis method without template. The CuCr2O4 samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Zeta potentials, respectively. The results indicated that cubic-like CuCr2O4 could be successfully synthesized by calcining the precursor at 600 °C, and the calcination temperature greatly influenced the morphology and optical performance of CuCr2O4. The pH at the point of zero charge (pHpzc) of the CuCr2O4 calcined at 600 °C was about 4.52. The photocatalytic activity of CuCr2O4 was evaluated for degradation of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) in the presence of H2O2 under visible light irradiation and the effects of the calcination temperature, dosage of photocatalyst, etc., on photocatalytic activity were studied in detail. The photocatalytic results revealed that the CuCr2O4 photocatalyst was of high activity for degradation of RhB (96.8%) and MB (99.5%), but very low activity for degradation of MO (14%). The CuCr2O4 sample calcined at 600 °C possesses the best photocatalytic activity, and the optimal dosage of the CuCr2O4 photocatalyst is 0.4 g/L.

  20. Effects of Cr, Ni and Cu on the Corrosion Behavior of Low Carbon Microalloying Steel in a Cl-Containing Environment

    Institute of Scientific and Technical Information of China (English)

    Yanlei Zhou; Jun Chen; Yang Xu; Zhenyu Liu

    2013-01-01

    The effects of Cr,Ni and Cu on the corrosion behavior of low carbon microalloying steel in a Cl-containing environment were investigated.The results revealed that the corrosion process could be divided into the initial stage in which the corrosion rate increased with accumulation of corrosion products and the later stage in which homogeneous and compact inner rust layers started to protect steel substrate out of corrosion mediums.The results of X-ray diffraction (XRD) indicated that the rust layers of the three-group steels (Cr,Cr-Ni and Cr-Ni-Cu steels) were composed of α-FeOOH,β-FeOOH,γ-FeOOH,Fe3O4 and large amounts of amorphous compounds.The content of amorphous compounds of Cr-Ni-Cu steel was about 2%-3% more than that of Cr-Ni steel.The results of electron probe microanalysis (EPMA) showed that Cr concentrated mainly in the inner region of the rust of Cr-Ni-Cu steel,inner/outer interface especially,whereas Ni was uniformly distributed all over the rust and Cu was noticed rarely after 73 wet/dry cycles.The addition of Cr and Ni was beneficial to the formation of dense and compact inner rust layer,which was the most important reason for the improvement of corrosion resistance of experimental steel.

  1. N–Mg dual-acceptor co-doping in CuCrO{sub 2} studied by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying, E-mail: 1080071@hnust.edu.cn [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Nie, Guo-Zheng [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Zou, Daifeng [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen 518055 (China); Tang, Jing-Wu [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Ao, Zhimin, E-mail: Zhimin.Ao@gdut.edu.cn [Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China)

    2016-11-25

    In this paper, N–Mg dual-acceptor co-doping in CuCrO{sub 2} is investigated by first-principles calculations. The electronic structure and formation energies of Mg substituting Cr-site, N substituting O-site, and co-doping of both Mg on Cr-site and N on O-site in CuCrO{sub 2} are calculated. It is found that the structure with N and Mg codoped at the nearest sites has the lowest energy due to a modest attractive interaction between the two dopants. Compared with single N or Mg doped CuCrO{sub 2}, the N–Mg codoped CuCrO{sub 2} has a lower formation energy and shallower transition level. In addition, the total density of states (DOS) analysis shows that more hole states appear above the Fermi level and higher DOS for N–Mg co-doping is obtained in the N–Mg codoped CuCrO{sub 2}, which is good to enhance the p-type conductivity in CuCrO{sub 2}. - Highlights: • N–Mg dual-acceptor co-doping in CuCrO{sub 2} is investigated. • N–Mg complex has a lower formation energy and shallower transition level. • More hole states appear above the Fermi level for N–Mg co-doping. • N–Mg co-doping in CuCrO{sub 2} can be expected to have more stable p-type conductivity.

  2. Genome Sequence Analysis of the Naphthenic Acid Degrading and Metal Resistant Bacterium Cupriavidus gilardii CR3.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Wang

    Full Text Available Cupriavidus sp. are generally heavy metal tolerant bacteria with the ability to degrade a variety of aromatic hydrocarbon compounds, although the degradation pathways and substrate versatilities remain largely unknown. Here we studied the bacterium Cupriavidus gilardii strain CR3, which was isolated from a natural asphalt deposit, and which was shown to utilize naphthenic acids as a sole carbon source. Genome sequencing of C. gilardii CR3 was carried out to elucidate possible mechanisms for the naphthenic acid biodegradation. The genome of C. gilardii CR3 was composed of two circular chromosomes chr1 and chr2 of respectively 3,539,530 bp and 2,039,213 bp in size. The genome for strain CR3 encoded 4,502 putative protein-coding genes, 59 tRNA genes, and many other non-coding genes. Many genes were associated with xenobiotic biodegradation and metal resistance functions. Pathway prediction for degradation of cyclohexanecarboxylic acid, a representative naphthenic acid, suggested that naphthenic acid undergoes initial ring-cleavage, after which the ring fission products can be degraded via several plausible degradation pathways including a mechanism similar to that used for fatty acid oxidation. The final metabolic products of these pathways are unstable or volatile compounds that were not toxic to CR3. Strain CR3 was also shown to have tolerance to at least 10 heavy metals, which was mainly achieved by self-detoxification through ion efflux, metal-complexation and metal-reduction, and a powerful DNA self-repair mechanism. Our genomic analysis suggests that CR3 is well adapted to survive the harsh environment in natural asphalts containing naphthenic acids and high concentrations of heavy metals.

  3. Characterization of akaganeite synthesized in presence of Al{sup 3+}, Cr{sup 3+}, and Cu{sup 2+} ions and urea

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K.E. [Instituto de Quimica, Universidad de Antioquia, A.A. 1226, Medellin (Colombia); Grupo de Estado Solido, Sede de Investigacion Universitaria, Universidad de Antioquia, A.A. 1226, Medellin (Colombia)], E-mail: kgarcia@pegasus.udea.edu.co; Barrero, C.A.; Morales, A.L. [Grupo de Estado Solido, Sede de Investigacion Universitaria, Universidad de Antioquia, A.A. 1226, Medellin (Colombia); Greneche, J.M. [Laboratoire de Physique de l' Etat Condense- UMR 6087, Universite du Maine, 72085 Le Mans Cedex 9 (France)

    2008-11-15

    Crystallographic, chemical, and physical properties of akaganeite formed in the presence of Al{sup 3+}, Cr{sup 3+}, and Cu{sup 2+} ions and urea when it is obtained by the hydrolysis of FeCl{sub 3} solutions were investigated by different techniques. X-ray diffraction (XRD), RT and 77 K Moessbauer spectrometry, Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) demonstrate that akaganeite is the only compound being formed independent of the type and concentration of the metallic cations and urea. Very small differences in some of the crystallographic, Moessbauer and infrared parameters for samples obtained in the presence of Cr, Cu, and Al ions at concentrations less than 10 mol%, were observed. However at 30 mol%, the presence of Al is able to reduce the average grain size of the final products. The presence of urea does not help to incorporate in an appreciable amount the Al into the akaganeite structure at least in the concentration ranges studied here. In contrast, they drastically affect the grain size of the products by reducing them. The present results may suggest that, because the properties of akaganeite are slightly affected by most alloying elements at low concentrations, this compound when formed as corrosion product of weathering and carbon steels should exhibit very similar properties to that of akaganeite obtained synthetically pure.

  4. Thermal vibrations in the metallic glass Cu64Zr36

    Science.gov (United States)

    Schönfeld, Bernd; Zemp, Jérôme; Stuhr, Uwe

    2017-01-01

    Neutrons with 14.7 and 34 meV energy were used to determine the elastic and inelastic part of the structure factor for the metallic glass Cu64Zr36 at 250 K. Based on the temperature dependence of the elastic scattering between 150 K and RT, an average mean-square displacement =0.027(3) ~{{{\\mathringA}}2} at 250 K is obtained. The experimental scattering-vector dependence of inelastic scattering in reference to elastic scattering is found to be well described by the Debye model. Both results are supported by molecular dynamics simulations. A procedure is presented to separate the elastic part also in total x-ray scattering. This allows the smearing of structural information due to thermal vibrations to be eliminated.

  5. [Cr(III)8M(II)6](12+) Coordination Cubes (M(II)=Cu, Co).

    Science.gov (United States)

    Sanz, Sergio; O'Connor, Helen M; Pineda, Eufemio Moreno; Pedersen, Kasper S; Nichol, Gary S; Mønsted, Ole; Weihe, Høgni; Piligkos, Stergios; McInnes, Eric J L; Lusby, Paul J; Brechin, Euan K

    2015-06-01

    [Cr(III)8M(II)6](12+) (M(II) =Cu, Co) coordination cubes were constructed from a simple [Cr(III) L3 ] metalloligand and a "naked" M(II) salt. The flexibility in the design proffers the potential to tune the physical properties, as all the constituent parts of the cage can be changed without structural alteration. Computational techniques (known in theoretical nuclear physics as statistical spectroscopy) in tandem with EPR spectroscopy are used to interpret the magnetic behavior.

  6. Biodegradation of the metallic carcinogen hexavalent chromium Cr(VI by an indigenously isolated bacterial strain

    Directory of Open Access Journals (Sweden)

    Das Alok

    2010-01-01

    Full Text Available Background : Hexavalent chromium [Cr(VI], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter. Materials and Methods: Our investigation involved microbial remediation of Cr(VI without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI were considered as Cr resistant. Results: The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30oC. At about 50 mg/L initial Cr(VI concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei. Conclusion: Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI.

  7. Photoinduced Reconstruction of Electronic Structure in Half-Metal CrO2

    Institute of Scientific and Technical Information of China (English)

    WU Xue-Wei; NIU Dong-Lin; LIU Xiao-Jun

    2007-01-01

    We investigate the photoinduced effects on the electronic structure for haft-metallic ferromagnet CrO2(Tc~390K),in which the conducting electrons are totally polarized,by using the LSDA+U method.A significant change is found for the band structure and the density of states (DOS) for CrO2 under photo-excitation,especially for the Cr 3dr2g band:disappearance of the spin-split band,suggesting collapse of the half-metallic state.We ascribe the change of electronic structure under photo-excitation to the wider one-electron band W via the strong hybridization of the down-spin Cr 3d and O 2p states.Furthermore we discuss the magnetic properties under photo-excitation.

  8. M/SBA-15(M=Cu、Fe、Cr)介孔分子筛的制备、表征及其催化NO+CO反应研究%Synthesis, characterization, and catalytic performance of mesoporous M/SBA-15 (M =Cu, Cr, Fe) for NO + CO reaction

    Institute of Scientific and Technical Information of China (English)

    薛君; 申力涛

    2013-01-01

    以介孔分子筛SBA-15为载体,采用浸渍法制备M/SBA-15(M=Cu、Fe、Cr)介孔分子筛催化剂.采用XRD、BET、FT-IR、H2-TPR和XPS等对样品进行分析表征,在固定床微型反应器中评价M/SBA-15(M=Cu、Fe、Cr)分子筛催化剂催化NO+ CO的反应性能.结果表明,负载金属的SBA-15分子筛仍保持高度有序的二维六方介孔结构,比表面积和孔径略有减少,负载的活性金属组分在SBA-15分子筛表面具有较高的分散度.Cu/SBA-15、Cr/SBA-15和Fe/SBA-15催化剂对NO+ CO反应体系均有一定活性,但由于活性金属自身的特性及其在载体表面负载量的差异,3种催化剂上呈现的NO还原活性不同,顺序为:Cr/SBA-15> Cu/SBA-15>Fe/SBA-15.%Mesoporous molecular sieves M/SBA-15 (M =Cu,Cr,Fe) were prepared by the incipient wetness impregnation method.The catalysts were characterized by XRD,BET,XPS,and H2-TPR techniques.The catalytic activity of the catalysts for NO + CO reaction was evaluated in a fixed bed reactor.The results showed that the hexagonal p6mm mesostructure of parent siliceous SBA-15 was maintained very well in M/SBA-15 (M =Cu,Cr,Fe),and its BET surface area and averge pore diameter decreased a little.The active metal components loaded on the surface of SBA-15 molecular sieves had higher dispersion degree.The catalytic activity of the catalysts depended on the loading of M (Cu,Cr,Fe).Cr/SBA-15 catalyst had better performance than Cu/SBA-15 and Fe/SBA-15 catalysts at relatively higher temperatures due to the higher content of active chromium,while the better deNOx performance of Cu/SBA-15 at low-temperature was ascribed to its excellent redox properties.

  9. Microstructure and strength of TiAl/40Cr joint diffusion bonded with vanadium-copper filler metal

    Institute of Scientific and Technical Information of China (English)

    何鹏; 冯吉才; 钱乙余; 张炳刚

    2002-01-01

    Intermetallics TiAl was diffusion-bonded to steel 40Cr in vacuum furnace with interlayer V/Cu. The results show that infinite sosoloid that made for bond performance is formed at the interface of V/Cu and Cu/40Cr, and three acting layers are formed at the interface of TiAl/V including Ti3Al layer at TiAl side, intermittent V5Al8 layer in the middle and Ti-V sosoloid at V side. Fragile reactors V5Al8 arising at the interface lead to bad performance of joints, and the strength of the joint is 200MPa, while it was still higher than the strength of the joint intermetallics TiAl to 40Cr steel diffusion-bonded directly. Intermetallic TiAl and 40Cr steel are diffusion-bonded successfully by using a composite isolation layer V/Cu.

  10. First-principles study on half-metallic zinc-blende CrS and its (001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Bin, E-mail: hnsqxb@163.com [Department of Mathematics and Information Sciences, North China university of Water Resources and Electric Power, Zhengzhou 450011 (China); Chen, Leiming [Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou, 450015 (China)

    2016-11-01

    Half-metallic magnets with complete (100%) spin polarization have attracted growing interest due to the potential in spintronic applications. In this paper, we use the first-principles calculations to explain the seeming contradiction between the recent experimental ferromagnetism (Demper et al., 2012 [22]) and the previous theoretical antiferromagnetic ground state for half-metallic zinc-blende CrS, and the experimental ferromagnetism of zinc-blende CrS arises from the substrate effect. We also show that both Cr- and S-terminated (001) surfaces of CrS preserve the bulk half-metallicity. The calculated surface energy indicates that the S-terminated (001) surface is more stable than the Cr-terminated (001) surface within the whole effective Cr chemical potentials, and thus the S-terminated (001) surface is more likely than the Cr-terminated (001) surface when the CrS thin films are grown on ZnSe substrate.

  11. Effect of Zn, Cu, Cr and Pb Chlorides on the Formation of Tricalcium Aluminate Trisulfate Hydrate

    Institute of Scientific and Technical Information of China (English)

    Wafaa S.Hegazi; Eisa E.Hekal; Essam A.Kishar; Maha R.Mohammed

    2008-01-01

    The effect of addition of Zn,Cu,Pb and Cr chlorides as admixtures on the hydration reaction of the system 3CaO·Al2O3-gypsum with molar ratio 1:3 was studied.Different ratios of each salt were used,namely 0.5%,2% and 4% by weight of the solid mixture.Hydration reaction was carried out at 35℃ for various time intervals from 0.5 h to up to 7 d.Hydration rate of the system 3CaO-Al2O3-CaSO4·2H2O in absence and presence of different salts was studied via the determination of the combined water contents.X-ray diffraction analysis showed that the ettringite was the only hydration product formed in the different mixes.The hydration products were investigated by scanning electron microscopy (SEM) and thermal gravimetric analysis.The results indicated that the rate of formation of ettringite and its microstructure depend on the admixture and its dosage.

  12. Contribution of Metal Defects in the Assembly Induced Emission of Cu Nanoclusters

    KAUST Repository

    Wu, Zhennan

    2017-03-20

    Aggregation/assembly induced emission (AIE) has been observed for metal nanoclusters (NCs), but the origin of the enhanced emission is not fully understood, yet. In this work, the significant contribution of metal defects on AIE is revealed by engineering the self-assembly process of Cu NCs using ethanol. The presence of ethanol leads to a rapid assembly of NCs into ultrathin nanosheets, promoting the formation of metal defects-rich surface. Detailed studies and computer simulation confirm that the metal defects-rich nanosheets possess increased Cu(I)-to-Cu(0) ratio, which greatly influences ligand-to-metal-metal charge transfer and therewith facilitates the radiative relaxation of excitons. Consequently, the Cu NCs self-assembly nanosheets exhibit obvious emission enhancement.

  13. Influence of Sn on Microstructure and Performance of Electric Vacuum Ag-Cu Filler Metal

    Directory of Open Access Journals (Sweden)

    SHI Lei

    2016-10-01

    Full Text Available Influence of Sn on microstructure, melting characteristic and brazing performance of electric vacuum Ag-Cu filler metal was studied by using scanning electronic microscope (SEM with energy disperse spectroscopy (EDS, differential scanning calorimetry (DSC and contrast tests. The results show that, while the addition of Sn is 4% (mass fraction,the same below, there is no brittle β-Cu phase in Ag60Cu filler metal,the effect on the processing performance is not obvious; with the increase of Sn content, the liquidus temperature of Ag60Cu filler metal decreases gradually, but the solidus temperature drops drastically,resulting in wider melting temperature range, and worse gap filling ability of filler metal. The Ag60Cu filler metal with Sn content of 4% has good spreading and metallurgical bonding abilities on copper plates, which are closer to that of BAg72Cu filler metal, and it can be processed into flake filler metal to replace the BAg72Cu flake filler metal to be used.

  14. Availability of heavy metals (Cd, Pb, And Cr) in agriculture from commercial fertilizers.

    Science.gov (United States)

    Nacke, H; Gonçalves, A C; Schwantes, D; Nava, I A; Strey, L; Coelho, G F

    2013-05-01

    The purpose of this study was to investigate the availability of the heavy metals cadmium (Cd), lead (Pb), and chromium (Cr) to soil and maize plants fertilized with different sources and doses of zinc (Zn) in a Rhodic Eutrudox soil. For that purpose, concentrations of Cd, Pb, and Cr were evaluated in leaf tissue and grains of maize plants and in 0-20 and 20-40 cm soil layers after fertilization with four doses of Zn from eight different sources of fertilizer. There was no accumulation of Cd, Pb, and Cr in maize grain and Cd and Cr in leaf tissue of the plants; nevertheless, there was accumulation of Pb in leaf tissue, showing its availability throughout different sources of Zn and consequent uptake by plants. Regarding the soil, it was observed that fertilizer from the different sources made Cd, Pb, and Cr available at increasing amounts proportional to increased Zn doses. Under experimental conditions, fertilization with Zn increased concentrations of heavy metals Cd, Pb and Cr in soil, further highlighting the importance of conducting more studies related to the application of mineral fertilizers for micronutrient supply and the availability of heavy metals.

  15. High temperature water gas shift reaction over Fe-Cr-Cu nanocatalyst fabricated by a novel method

    Energy Technology Data Exchange (ETDEWEB)

    Latifi, Seyed Mahdi; Salehirad, Alireza [Iranian Research Organization for Science and Technology (IROST), Tehran (Iran, Islamic Republic of)

    2016-02-15

    Fe-Cr-Cu nanocatalyst was synthesized through an inorganic-precursor thermolysis approach and exploited for high temperature water gas shift reaction. The results demonstrated that the method used for the nanocatalyst fabrication led to smaller crystallite size (32.9 nm) and higher BET surface area (127.3m{sup 2}/g) compared to those of a reference sample (65.5 nm, 78.6m{sup 2}/g) prepared by co-precipitation conventional method. Furthermore, the obtained data for catalytic activity showed that the catalyst prepared via inorganic precursor has better activity than the reference sample in all studied temperatures (350-500 .deg. C) and also exhibited higher catalytic activity than a commercial Fe-Cr- Cu catalyst in higher temperatures (more than 450 .deg. C).

  16. Modeling of electrodialytic and dialytic removal of Cr, Cu and As from CCA-treated wood chips

    DEFF Research Database (Denmark)

    Ribeiro, Alexandra; Rodriguez-Maroto, J.M.; Mateus, Eduardo

    2007-01-01

    A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a saturated bed of wood chips containing chromium, copper and arsenic. The movement of Cr, Cu and As is mathematically modeled taking into account the diffusion transport resulting from the concentra......A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a saturated bed of wood chips containing chromium, copper and arsenic. The movement of Cr, Cu and As is mathematically modeled taking into account the diffusion transport resulting from......+ and NO3 used as electrolyte solutions in the electrode compartments, and oxalate ions and protons incorporated with the oxalic acid solution during wood chips incubation. The model simulation also takes into account that OH generated on the cathode, during electrodialytic remediation, is periodically...

  17. Transformation of natural ferrihydrite aged in situ in As, Cr and Cu contaminated soil studied by reduction kinetics

    DEFF Research Database (Denmark)

    Nielsen, Sanne Skov; Kjeldsen, Peter; Hansen, Hans Christian Bruun;

    2014-01-01

    Several soil remediation techniques for As, Cu and Cr contaminated soil utilize adsorption of contaminants to ferrihydrite as the removal mechanism, even though ferrihydrite will transform to secondary iron oxides and part of the sorption capacity will be lost. Transformation of ferrihydrite...... following 4 yr of in situ burial at a contaminated site was examined in samples of impure (Si-bearing) ferrihydrite in soil heavily polluted with As, Cr and Cu. The samples are so-called iron water treatment residues (Fe-WTR) precipitated from anoxic groundwater during aeration. The extent of transformation...... the fate of ferrihydrite and associated contaminants during burial enabling an improvement of the methods for amending contaminated soil with Fe-WTR. (C) 2014 Elsevier Ltd. All rights reserved....

  18. Does Metal Transfer Differ on Retrieved Ceramic and CoCr Femoral Heads?

    Directory of Open Access Journals (Sweden)

    Eliza K. Fredette

    2015-01-01

    Full Text Available Metal transfer has been observed on retrieved THA femoral heads for both CoCr and ceramic bearing materials. In vitro wear testing has shown increased wear to polyethylene acetabular liners with the presence of metal transfer. This study sought to investigate the extent of metal transfer on the bearing surface of CoCr and ceramic femoral heads and identify prevalent morphologies. Three bearing couple cohorts: M-PE (n=50, C-PE (n=35, and C-C (n=15, were derived from two previously matched collections (n=50/group of CoCr and ceramic femoral heads. From the three cohorts, 75% of the femoral heads showed visual evidence of metal transfer. These femoral heads were analyzed using direct measurement, digital photogrammetry, and white light interferometry. Surface area coverage and curved median surface area were similar among the three cohorts. The most prevalent metal transfer patterns observed were random stripes (n=21/75, longitudinal stripes (n=17/75, and random patches (n=13/75. Metal transfer arc length was shorter in the M-PE cohort. Understanding the morphology of metal transfer may be useful for more realistic recreation of metal transfer in in vitro pin-on-disk and joint simulators studies.

  19. Evaluation of Acinetobacter sp. B9 for Cr (VI) resistance and detoxification with potential application in bioremediation of heavy-metals-rich industrial wastewater.

    Science.gov (United States)

    Bhattacharya, Amrik; Gupta, Anshu

    2013-09-01

    Present work demonstrates Cr (VI) detoxification and resistance mechanism of a newly isolated strain (B9) of Acinetobacter sp. Bioremediation potential of the strain B9 is shown by simultaneous removal of major heavy metals including chromium from heavy-metals-rich metal finishing industrial wastewater. Strain B9 tolerate up to 350 mg L(-1) of Cr (VI) and also shows level of tolerance to Ni (II), Zn (II), Pb (II), and Cd (II). The strain was capable of reducing 67 % of initial 7.0 mg L(-1) of Cr (VI) within 24 h of incubation, while in presence of Cu ions 100 % removal of initial 7.0 and 10 mg L(-1) of Cr (VI) was observed with in 24 h. pH in the range of 6.0-8.0 and inoculum size of 2 % (v/v) were determined to be optimum for dichromate reduction. Fourier transform infrared spectroscopy and transmission electron microscopy studies suggested absorption or intracellular accumulation and that might be one of the major mechanisms behind the chromium resistance by strain B9. Scanning electron microscopy showed morphological changes in the strain due to chromium stress. Relevance of the strain for treatment of heavy-metals-rich industrial wastewater resulted in 93.7, 55.4, and 68.94 % removal of initial 30 mg L(-1) Cr (VI), 246 mg L(-1) total Cr, and 51 mg L(-1) Ni, respectively, after 144 h of treatment in a batch mode.

  20. Electrochemical corrosion behavior of Cu-40Ni-20Cr alloys with different grain sizes in solutions containing chloride ions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The electrochemical corrosion behavior of the two Cu-40Ni-20Cr alloys prepared by conventional casting(CA) and mechanical alloying(MA) with the different grain sizes was studied by using open-circuit potential(OCP), potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) methods in solutions containing chloride ions. The results show that the free corrosion potentials of the two alloys move towards negative values, corrosion currents increase and therefore corrosion rates become faster with the increase of chloride ion concentrations. EIS plots of CACu-40Ni-20Cr alloy are composed of single capacitive loop, while EIS plots of MACu-40Ni-20Cr alloy are composed of double capacitive loops in solution containing lower chloride ion concentrations. EIS plots of the two alloys have Warburg impedance with the increase of chloride ion concentrations.Corrosion rates of MACu-40Ni-20Cr alloy become faster than those of CACu-40Ni-20Cr alloy obviously in solutions containing the same chloride ion concentrations because MACu-40Ni-20Cr alloy is able to produce large concentrations of grain boundaries in the course of reduction in grain size by mechanical alloying.

  1. Heat Transfer Analysis of Two Kinds of Mechanically Jointed GBST1308/CuCrZr Plasma Facing Components of EAST

    Institute of Scientific and Technical Information of China (English)

    CHONG Fali; CHEN Junling; LI Jiangang; ZHENG Xuebin; EAST team

    2008-01-01

    Doped graphite GBST1308,mechanically jointed to CuCrZr alloys,will be applied on EAST superconducting as plasma facing material (PFM).Two joint structures called joint-1 and joint-2 were evaluated by means of thermal response tests using electron beam facility.The experimental results showed that the temperature differences of two joints were not significant,and the maximum surface temperature was about 1055℃ at a load of 4 MW/m2,which had a good agreement with the simulated results by ANSYS code.The results indicated that the doped graphite GBST1308/CuCrZr mock-up can withstand heat flux deposition of 4 MW/m2 except at the screw-fastened region,and joint-2 could be more suitable to higher heat flux region such as divertor target.But under the higher heat flux,both joints are unacceptable,an advanced PFM and its integration with the heat sink have to be developed,for example,vacuum plasma spraying tungsten coatings on the CuCrZr might be a good choice.

  2. Using Alloys of Cr-Ni-Co system as metallic bond in powder metallurgy products

    Directory of Open Access Journals (Sweden)

    A. M. Gazaliyev

    2015-10-01

    Full Text Available There is studied the possibility of using alloys of the Cr-Ni-Cо system as a metallic bond in producing ceramet. As the basic material there was used titanium carbide. There were measured such mechanical properties as bending strength, tensile strength, impact viscosity. There is considered a possibility of using ceramet with a metallic bond of the Cr-Ni-Co system as a refractory material. As a heat resistance indicator there was estimated the limit of long durability. It is established that in the studied range of temperatures the material properties are the function of the bond content.

  3. Effect of different extracting solutions on the electrodialytic remediation of CCA-treated wood waste Part I. - Behaviour of Cu and Cr

    DEFF Research Database (Denmark)

    Velizarova, E.; Ribeiro, A. B.; Mateus, E.

    2004-01-01

    Removal of Cu and Cr from chromated copper arsenate (CCA)-treated wood waste under batch electrodialytic conditions was studied. The effect of different types of extracting solutions, such as deionised water or aqueous solutions of NaCl, formic acid, oxalic acid, and EDTA, on the magnitude...... and direction of the fluxes of Cu- and Cr-containing species in the electrodialytic cell was investigated. Oxalic acid was found to have the best performance if simultaneous removal of the two elements is required (removal efficiencies of 80.5% for Cu and 87.4% for Cr, respectively). A mixture of oxalic acid....... The latter were not present if EDTA was the extracting solution resulting in directing the Cu and Cr fluxes to the anode compartment. Contrary, these fluxes were exclusively to the cathode compartment if deionised water or an aqueous solution of NaCl were used. These extracting solutions proved suitable...

  4. Synthesis of thiol-functionalized MCM-41 mesoporous silicas and its application in Cu(II), Pb(II), Ag(I), and Cr(III) removal

    Energy Technology Data Exchange (ETDEWEB)

    Wu Shengju; Li Fengting, E-mail: fengting@tongji.edu.cn; Xu Ran; Wei Shihui [Tongji University, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering (China); Li Guangtao [Tsinghua University, Department of Chemistry (China)

    2010-08-15

    Thiol-functionalized MCM-41 mesoporous silicas were synthesized via evaporation-induced self-assembly. The mesoporous silicas obtained were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption analysis, Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The products were used as adsorbents to remove heavy metal ions from water. The mesoporous silicas (adsorbent A) with high pore diameter (centered at 5.27 nm) exhibited the largest adsorption capacity, with a BET surface area of 421.9 m{sup 2} g{sup -1} and pore volume of 0.556 cm{sup 3-1}. Different anions influenced the adsorption of Cu(II) in the order NO{sub 3}{sup -} < OAc{sup -} < SO{sub 4}{sup 2-} < CO{sub 3}{sup 2-} < Cit{sup -} < Cl{sup -}. Analysis of adsorption isotherms showed that Cu{sup 2+}, Pb{sup 2+}, Ag{sup +}, and Cr{sup 3+} adsorption fit the Redlich-Peterson nonlinear model. The mesoporous silicas synthesized in the work can be used as adsorbents to remove heavy metal ions from water effectively. The removal rate was high, and the adsorbent could be regenerated by acid treatment without changing its properties.

  5. Characterization of Zr-Cu Base Metallic Glasses by means of Hydrogen Internal Friction Peak

    OpenAIRE

    Mizubayashi, H.; Nakamura, I.; Yamagishi, K.; Tanimoto, H.

    2007-01-01

    The hydrogen internal friction peak in Zr50-metallic glasses (Zr50Cu50, Zr50Cu40Al10 and Zr50Cu35Al10Ni5) was studied. The hydrogen internal friction peak was shifted exponentially to lower temperatures with increasing hydrogen concentration similarly to other Zr-Cu base metallic glasses reported in the literature. The peak height increased in proportion to the square-root of hydrogen concentration. These results were discussed in the view point of the hydrogen induced structural relaxation i...

  6. Effect of Cu on the evolution of precipitation in an Fe-Cr-Ni-Al-Ti maraging steel

    Energy Technology Data Exchange (ETDEWEB)

    Schnitzer, Ronald, E-mail: ronald.schnitzer@unileoben.ac.at [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Schober, Michael [Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Zinner, Silvia [Boehler Edelstahl GmbH and Co KG, Mariazeller Strasse 25, A-8605 Kapfenberg (Austria); Leitner, Harald [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)] [Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)

    2010-06-15

    The evolution of precipitates in an Fe-Cr-Ni-Al-Ti stainless maraging steel alloyed with Cu was investigated during aging at 525 deg. C. Atom probe tomography was used to reveal the development of precipitates and to determine their chemical composition. Two types of precipitates were observed to form during the aging process. Based on their chemical composition these are assumed to be NiAl B2 and Ni{sub 3}(Ti,Al) ({eta}-phase). The two phases of precipitates were found to develop independently of each other and the addition of Cu was found to accelerate precipitation. However, the effect of Cu on the nucleation of these phases is different: on the one hand, in the case of NiAl, Cu is incorporated and thus reduces the activation energy by reducing the lattice misfit; on the other hand, Cu acts as a nucleation site for the precipitation of Ni{sub 3}(Ti,Al) by forming independent Cu clusters.

  7. Enhanced magnetic response and metallicity in AB stacked bilayer graphene via Cr-doping

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Jyoti [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Kashyap, Manish K., E-mail: manishdft@gmail.com [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Saini, Hardev S. [Department of Physics, Panjab University, Chandigarh 160014 (India); Reshak, Ali H. [New Technologies – Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia)

    2015-11-15

    First-principles study for the electronic and magnetic properties of Cr atom doping in lower layer of AB bernal stacked bilayer graphene (BLG) is presented. This doping is analysed in three different configurations; (i) Hollow type (above the centre of C hexagon), (ii) Top-type (directly on the top of any C atom) and (iii) Bridge type (mid point of any C–C bond). It has been observed that the doping of Cr atom enlarges the interlayer spacing in BLG as compared to pure one. The Top-type (T-type) doping is found to be most stable energetically. The doping of Cr atom in all configurations generates the large spin polarization and induces the appreciable magnetic moment. Half metallicity has been obtained in Hollow type (H-type) doping with a suitable band gap of 0.28 eV in minority spin channel. The origin of magnetism has been identified via interactions of 3d-states of doped Cr atom with p-states of inequivalent C atoms present in the vicinity of doping site. The electron densities plots also confirm the metallic nature of Cr-doped BLG. Our results reveal that the resultant BLG has potential for futuristic applications such as high frequency transistors, spintronics, photodetectors and energy resources. - Highlights: • Cr-doping in bilayer graphene induces magnetic channel. • Half metallicity is observed only in H-type Cr-doping in graphene. • T-type doping is most energetically stable among all types (H-type, B-type and T-type). • The strong hybridization of Cr-3d states with C-p states governs the magnetism in BLG.

  8. Cr(III,Mn(II,Fe(III,Co(II,Ni(II,Cu(II and Zn(II Complexes with Diisobutyldithiocarbamato Ligand

    Directory of Open Access Journals (Sweden)

    Mohammad Tarique

    2011-01-01

    Full Text Available The synthesis of sulphur and nitrogen containing dithiocarbamato ligand derived from diisobutylamine as well as its coordination compounds with 3d series transition metals is presented. These synthesized compounds were characterized on the basis of elemental analysis, conductometric measurements and IR spectral studies. The analytical data showed the stoichiometry 1:2 and 1:3 for the compounds of the types ML2 {M=Mn(II, Co(II, Ni(II, Cu(II and Zn(II} and M'L3{M'=Cr(III and Fe(III} respectively. The conductometric measurements proved the non-electrolytic behaviour of all the compounds. The bidentate nature of dithiocarbamato moiety was confirmed on the basis of IR spectral data.

  9. Deformation-induced martensitic transformation in Cu-Zr-Al(Ti) bulk metallic glass composites

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ram Bachchan; Pauly, Simon; Das, Jayanta; Eckert, Juergen [Institut fuer Komplexe Materialien, IFW Dresden (Germany)

    2009-07-01

    Plastic deformation of Cu-Zr-(Al, Ti) bulk metallic glass (BMG) composites induces a martensitic phase transformation from the B2 to the B19* CuZr phase. Addition of Ti to binary Cu-Zr increases the temperature above which the B2 CuZr phase becomes stable. This affects the phase formation upon quenching in Cu-Zr-Ti BMG composites. The deformation-induced martensitic transformation is believed to cause the strong work hardening and to contribute to the large compressive deformability with plastic strains up to 15%.

  10. Al2O3-Cact-(CuO, Cr2O3, Co3O4 Adsorbents-Catalysts: Preparation and Characterization

    Directory of Open Access Journals (Sweden)

    Gitana DABRILAITĖ-KUDŽMIENĖ

    2013-03-01

    Full Text Available Al2O3-Cact-(CuO, Cr2O3 Co3O4 adsorbents-catalysts were prepared using Al2O3-Cact (alumina gel–activated carbon adsorbent and different amount of CuO, Cr2O3 and Co3O4. The active components were incorporated into wet alumina gel–carbon mixture using different conditions (by sol-gel method and mixing a milled metal oxides. Equilibrium adsorptive capacity measurements of alcohol vapours were carried out in order to determine the influence of preparation conditions on the stability of prepared adsorbents–catalysts. Specific surface area of the prepared adsorbents-catalysts were measured by BET method. It was established that for adsorbent-catalyst produced by sol-gel method SBET = 244.7 m2/g. Surface area SBET = 29.32 m2/g was obtained for adsorbent-catalyst with metal oxides. On the basis of these results it was assumed that active carbon was lost in this adsorbent-catalyst during the preparation process. Sol-gel derived adsorbent–catalyst was tested for the oxidation of methanol vapours. Catalytic oxidation was carried out in fixed-bed reactor. Experimental data indicate that adsorptive capacity of the adsorbent–catalyst is (3.232 – 3.259 mg/m3 CH3OH at relative air humidity is 40 % – 50 %. During a fast heating of CH3OH – saturated adsorbent-catalyst a part of adsorbate is converted to CO2 and H2O. Methanol conversion increases with increasing of adsorbent-catalyst heating rate.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3832

  11. A Comparative Physics Study of Commercial PWR Cores using Metallic Micro-cell UO{sub 2}-Cr (or Mo) Pellets with Cr-based Cladding Coating

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dae Hee; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of); In, Wang Kee [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this work, a comparative neutronic analysis of the cores using ATFs which include metallic micro-cell UO{sub 2}-Cr, UO{sub 2}-Mo pellets and Cr-based alloy coating on cladding was performed to show the effects of the ATF fuels on the core performance. In this study, the cores having different ATFs use the same initial uranium enrichments. The ATF concepts studied in this work are the metallic microcell UO{sub 2} pellets containing Cr or Mo with cladding outer coating composed of Cr-based alloy which have been suggested as the ATF concepts in KAERI (Korea Atomic Energy Research Institute). The metallic micro-cell pellets and Cr-based alloy coating can enhance thermal conductivity of fuel and reduce the production of hydrogen from the reaction of cladding with coolant, respectively. The objective of this work is to compare neutronic characteristics of commercial PWR equilibrium cores utilizing the different variations of metallic micro-cell UO{sub 2} pellets with cladding coating composed of Cr-based alloy. The results showed that the cores using UO{sub 2}-Cr and UO{sub 2}-Mo pellets with Cr-based alloy coating on cladding have reduced cycle lengths by 60 and 106 EFPDs, respectively, in comparison with the reference UO{sub 2} fueled core due to the reduced heavy metal inventories and large thermal absorption cross section but they do not have any significant differences in the core performances parameters. However, it is notable that the core fueled the micro-cell UO{sub 2}-Mo pellet and Cr-based alloy coating has considerably more negative MTC and slightly more negative FTC than the other cases. These characteristics of the core using micro-cell UO{sub 2}-Mo pellet and Cr-based alloy coating is due to the hard neutron spectrum and large capture resonance cross section of Mo isotopes.

  12. Half-metallicity and magnetism of the full-Heusler compounds KYX2 (Y=Ti, V, and Cr; X=C, N, and O)

    Science.gov (United States)

    Dehghanzadeh, M.; Ahmadian, F.

    2017-02-01

    The electronic structure and half-metallic (HM) properties of new alloys KYX2 (Y=Ti, V, and Cr; X=C, N, and O) containing transition metals and sp elements were investigated within the density functional theory (DFT) using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method. It was found that these new compounds can be experimentally synthesized because of their negative formation energies. The total energy calculations showed that in all compounds, the stable state structure was a ferromagnetic AlCu2Mn-type structure except for KTiC2 and KTiN2 which were stable in a nonmagnetic (NM) AlCu2Mn-type structure. The KTiO2 in both structures, KCrO2 in AlCu2Mn-type structure, and KVO2 in CuHg2Ti-type structure were half-metallic ferromagnets. KVO2 in AlCu2Mn-type structure was a special case with a ferromagnetic semiconducting behavior. The origin of minority band gaps for KTiO2 in both structures was also studied using the band structure calculations. The total magnetic moments of HM compounds were integer values which were in agreement with Slater-Pauling rule (Mtot=Ztot-12). Furthermore, the regions of half-metallictiy in HM compounds were considerably wider than those of Heusler compounds including transition metals, indicating the high robustness of half-metallicity with variation of lattice constants.

  13. Review of Ni-Cu Based Front Side Metallization for c-Si Solar Cells

    Directory of Open Access Journals (Sweden)

    Mehul C. Raval

    2013-01-01

    Full Text Available Given the high percentage of metal cost in cell processing and concerns due to increasing Ag prices, alternative metallization schemes are being considered. Ni-Cu based front side metallization offers potential advantages of finer grid lines, lower series resistance, and reduced costs. A brief overview of various front side patterning techniques is presented. Subsequently, working principle of various plating techniques is discussed. For electroless plated Ni seed layer, fill factor values nearing 80% and efficiencies close to 17.5% have been demonstrated, while for Light Induced Plating deposited layers, an efficiency of 19.2% has been reported. Various methods for qualifying adhesion and long term stability of metal stack are discussed. Adhesion strengths in the range of 1–2.7 N/mm have been obtained for Ni-Cu contacts tabbed with conventional soldering process. Given the significance of metallization properties, different methods for characterization are outlined. The problem of background plating for Ni-Cu based metallization along with the various methods for characterization is summarized. An economic evaluation of front side metallization indicates process cost saving of more than 50% with Ni-Cu-Sn based layers. Recent successful commercialization and demonstration of Ni-Cu based metallization on industrial scale indicate a potential major role of Ni-Cu based contacts in near future.

  14. Understanding Active Metal Reaction Kinetis with Cu-Mg Replacement Reaction

    Indian Academy of Sciences (India)

    Ilhami Ceyhun; Zafer Karagolge

    2017-02-01

    Metal substitution reactions are simple redox reactions. Thesereactions demonstrate the relative activity and the electrochemicalseries of metals. In particular, the purpose of thisstudy is to help students comprehend the displacement reactionamong, Mg metal and solutions containing Cu$^{+2}$, Ni$^{+2}$,Pb$^{+2}$, Cd$^{+2}$, Co$^{+2}$. This study is an important experiment towardsunderstanding reaction kinetics.

  15. Microstructure and mechanical properties of Zr-Cu-Al bulk metallic glasses

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Zr49Cu46Al5 and Zr48.5Cu46.5Al5 bulk metallic glasses(BMGs) with diameter of 5 mm were prepared through water-cooled copper mold casting. The phase structures of the two alloys were identified by X-ray diffractometry(XRD). The thermal stability was examined by differential scanning calorimetry(DSC). Zr49Cu46Al5 alloy shows a glass transition temperature, Tg, of about 689 K, an crystallization temperature, Tx, of about 736 K. The Zr48.5Cu46.5Al5 alloy shows no obvious exothermic peak. The microstructure of the as-cast alloys was analyzed by transmission electron microscopy(TEM). The aggregations of CuZr and CuZr2 nanocrystals with grain size of about 20 nm are observed in Zr49Cu46Al5 nanocrystalline composite, while the Zr48.5Cu46.5Al5 alloy containing many CuZr rmartensite plates is crystallized seriously. Mechanical properties of bulk Zr49Cu46Al5 nanocrystalline composite and Zr48.5Cu46.5Al5 alloy measured by compression tests at room temperature show that the work hardening ability of Zr48.5Cu46.5Al5 alloy is larger than that of Zr49Cu46Al5 alloy.

  16. Cr-resistant rhizo- and endophytic bacteria associated with Prosopis juliflora and their potential as phytoremediation enhancing agents in metal-degraded soils

    Directory of Open Access Journals (Sweden)

    Muhammad Umar Khan

    2015-01-01

    Full Text Available Prosopis juliflora is characterized by distinct and profuse growth even in nutritionally poor soil and environmentally stressed conditions and is believed to harbor some novel heavy metal-resistant bacteria in the rhizosphere and endosphere. This study was performed to isolate and characterize Cr-resistant bacteria from the rhizosphere and endosphere of P. juliflora growing on the tannery effluent contaminated soil. A total of 5 and 21 bacterial strains were isolated from the rhizosphere and endosphere, respectively, could tolerate Cr up to 3000 mg l-1. These isolates also exhibited tolerance to other toxic heavy metals such as, Cd, Cu, Pb and Zn, and high concentration (174 g l-1 of NaCl. Moreover, most of the isolated bacterial strains showed one or more plant growth-promoting activities. The phylogenetic analysis of the 16S rRNA gene indicated a higher and wider range of population of Cr-resistant bacteria in the endosphere than rhizosphere and the predominant species included Bacillus, Staphylococcus and Aerococcus. As far as we know, this is the first report detecting rhizo- and endophytic bacterial population associated with P. juliflora growing on the tannery effluent contaminated soil. The inoculation of three isolates to ryegrass (Lolium multiflorum L. improved plant growth and heavy metal removal from the tannery effluent contaminated soil suggesting that these bacteria could enhance the establishment of the plant in contaminated soil and also improve the efficiency of phytoremediation of heavy metal-degraded soils.

  17. Synthesis, characterization and photocatalytic activity of cubic-like CuCr{sub 2}O{sub 4} for dye degradation under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenhui, E-mail: cewhyuan@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology 510640, Guangdong, Guangzhou (China); Liu, Xiaoxia [School of Chemistry and Chemical Engineering, South China University of Technology 510640, Guangdong, Guangzhou (China); Li, Li [College of Environmental Science and Engineering, South China University of Technology 510006, Guangdong, Guangzhou (China)

    2014-11-15

    Graphical abstract: Hydrothermal synthesis method was applied for preparation of cubic-like CuCr{sub 2}O{sub 4} spinel nanoparticles without template. The synthesized cubic-like CuCr{sub 2}O{sub 4} shows excellent photocatalytic activity for degradation of RhB and MB cationic dyes but not for MO anionic dye in the presence of H{sub 2}O{sub 2} under visible light irradiation. - Highlights: • The cubic-like CuCr{sub 2}O{sub 4} spinel nanoparticles were successfully synthesized via the hydrothermal synthesis method. • The calcination temperature has a great influence on the morphology, particle size and photocatalytic activity of CuCr{sub 2}O{sub 4}. • The pH at the point of zero charge (pH{sub pzc}) of the CuCr{sub 2}O{sub 4} calcined at 600 °C is about 4.52. • The cubic-like CuCr{sub 2}O{sub 4} calcined at 600 °C exhibits excellent photocatalytic activity for RhB and MB in the presence of H{sub 2}O{sub 2} under visible-light irradiation. - Abstract: CuCr{sub 2}O{sub 4} nanoparticles with cubic-like morphology were prepared via hydrothermal synthesis method without template. The CuCr{sub 2}O{sub 4} samples were characterized by thermogravimetry and differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS) and Zeta potentials, respectively. The results indicated that cubic-like CuCr{sub 2}O{sub 4} could be successfully synthesized by calcining the precursor at 600 °C, and the calcination temperature greatly influenced the morphology and optical performance of CuCr{sub 2}O{sub 4}. The pH at the point of zero charge (pH{sub pzc}) of the CuCr{sub 2}O{sub 4} calcined at 600 °C was about 4.52. The photocatalytic activity of CuCr{sub 2}O{sub 4} was evaluated for degradation of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) in the presence of H{sub 2}O{sub 2} under visible light irradiation and the effects of the

  18. Magnetic properties of metallic glasses based on Fe-Cr from Mössbauer spectroscopy

    Science.gov (United States)

    Gwiazda, J.; Mariańska, E.; Oleniacz, J.; Peryt, M.; Zych, W.

    1990-07-01

    Spectra of metallic foils Fe80- x Cr x B2 ( x=6, 10, 15, 20) and Fe60Cr20B12Si8 were measured at range 4.2 K 300 K. Mössbauer data were analysed by Window’s Hesse-Rübartsch’s and Janot’s methods. The influence of the temperature and the Cr-content is discussed. The coefficient B 3/2 in Bloch’s law was calculated. Curie and crystallization temperature were taken from the DTA-DTMG method [1]. For finding the Curie temperature of the sample Fe60Cr20B20 we used ac susceptibility, but this sample is not homogeneous.

  19. Work function anisotropy and surface stability of half-metallic CrO(2)

    NARCIS (Netherlands)

    Attema, J. J.; Uijttewaal, M. A.; de Wijs, G. A.; de Groot, R. A.

    2008-01-01

    Insight in the interplay between work function and stability is important for many areas of physics. In this paper, we calculate the anisotropy in the work function and the surface stability of CrO(2), a prototype half-metal, and find an anisotropy of 3.8 eV. An earlier model for the relation betwee

  20. Work function anisotropy and surface stability of half-metallic CrO(2)

    NARCIS (Netherlands)

    Attema, J. J.; Uijttewaal, M. A.; de Wijs, G. A.; de Groot, R. A.

    Insight in the interplay between work function and stability is important for many areas of physics. In this paper, we calculate the anisotropy in the work function and the surface stability of CrO(2), a prototype half-metal, and find an anisotropy of 3.8 eV. An earlier model for the relation

  1. Facile synthesis and characterization of trimesic acid-Cu based metal organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Sahiner, Nurettin, E-mail: sahiner71@gmail.com [Canakkale Onsekiz Mart University, Faculty of Sciences and Arts, Department of Chemistry, Terzioglu Campus, 17100 Canakkale (Turkey); Nanoscience and Technology Research and Application Center (NANORAC), Terzioglu Campus, 17100 Canakkale (Turkey); Sel, Kivanc [Canakkale Onsekiz Mart University, Faculty of Sciences and Arts, Department of Physics, Terzioglu Campus, 17100 Canakkale (Turkey); Nanoscience and Technology Research and Application Center (NANORAC), Terzioglu Campus, 17100 Canakkale (Turkey); Ozturk, Omer Faruk; Demirci, Sahin; Terzi, Gozde [Canakkale Onsekiz Mart University, Faculty of Sciences and Arts, Department of Chemistry, Terzioglu Campus, 17100 Canakkale (Turkey)

    2014-09-30

    Graphical abstract: - Highlights: • Various MOFs based on trimesic acid (TMA) and various Cu (II) salts. • Benign preparation of TMA-Cu based MOFs in DI water and ethanol. • TMA-Cu MOFs with the mole ratio of Cu(II) to TMA varying between 1.5 and 2. • TMA-Cu MOF with conductivity values were 8.26E−08–5.29E−11 (S/cm). - Abstract: Metal-organic frameworks based on trimesic acid (TMA) as organic linker and Cu (II) as metal ions from different metal salts such as CuCl{sub 2}, Cu(NO{sub 3}){sub 2}, CuSO{sub 4} and Cu(CH{sub 3}COOH){sub 2} were prepared in relatively environmentally friendly media e.g., at room temperature in DI water and at the boiling point of ethanol. The prepared TMA-Cu MOFs showed very interesting porosity and optical coloring based on the source of the used metal salts and preparation medium. The prepared MOFs were characterized in terms of their porosity with BET measurements and it was found that about 850 m{sup 2}/g for the MOF prepared from Cu(NO{sub 3}){sub 2} salt in ethanol. The amounts of metal ions connected to TMA were determined by atomic absorption spectroscopy measurements (AAS) after dissolution of TMA-Cu MOFs by concentrated HCl treatments. From AAS measurements the mole ratio of Cu(II) to TMA was found to vary between 1.5 and 2, depending on the source of metal ions and the solvent used during preparation. The structural analysis and thermal characterization of the prepared MOFs were done by using FT-IR and TGA analysis, respectively. Additionally, TMA-Cu based MOF disks were prepared and their conductivities were determined by I–V measurements. The conductivity of TMA-Cu MOFs was calculated to be between 8.26E−08 and 5.29E−11 S/cm.

  2. Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08354, and UNS N08926), and Cr-Ni-Fe-N Low-Carbon Alloy (UNS R20033) Bar and Wire, and Ni-Cr-Fe-Mo-N Alloy (UNS N08936) Wire

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2016-01-01

    Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08354, and UNS N08926), and Cr-Ni-Fe-N Low-Carbon Alloy (UNS R20033) Bar and Wire, and Ni-Cr-Fe-Mo-N Alloy (UNS N08936) Wire

  3. In Situ Synthesis of Ceramic Reinforcements for Carbon/CuCrZr Joints Brazed with Composite Fillers

    Science.gov (United States)

    Mao, Yangwu; Yu, Si; Deng, Quanrong; Zhao, Pei

    2016-12-01

    Brazing of two kinds of carbon materials including graphite and carbon fiber-reinforced carbon composites to copper alloys has been realized with CuTiH2 + BN composite fillers. The microstructure characterization reveals that the ceramic reinforcements containing TiN particles and TiB whiskers have been synthesized by in situ reaction of BN additives with Ti discomposed from TiH2 in the composite filler. The filler layer of the joints is mainly composed of Cu-based solid solutions [Cu (ss)] and Ti-Cu intermetallics along with ceramic reinforcements. Furthermore, a continuous thin reaction layer mainly containing TiC is developed at the interface close to the carbon substrates. The growth of TiC layer is mainly controlled by the diffusion of carbon from the substrates into the liquid filler through the TiC layer formed. The interface evolution of the graphite/CuCrZr joints has been discussed. The electrical resistivity of the joining area is relatively low, which highly meets the requirement for the carbon commutator applications.

  4. Characterization of delafossite-CuCrO{sub 2} thin films prepared by post-annealing using an atmospheric pressure plasma torch

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong-Ying, E-mail: hychen@cc.kuas.edu.tw [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chiken Kuang Road, Kaohsiung 807, Taiwan, ROC (China); Yang, Wei-Jung; Chang, Kuei-Ping [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chiken Kuang Road, Kaohsiung 807, Taiwan, ROC (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Dealfossite-CuCrO{sub 2} thin film was prepared using sol-gel processing and post-annealing with an atmospheric pressure plasma torch. Black-Right-Pointing-Pointer X-ray diffraction pattern shows pure delafossite-CuCrO{sub 2} thin films can be obtained. Black-Right-Pointing-Pointer The average transmittance of the film was 66% in the visible region and the direct optical bandgap was 3.08 eV. Black-Right-Pointing-Pointer The electrical conductivity of the film was 2.7 Multiplication-Sign 10{sup -2} Scm{sup -1} with the carrier concentration of 2.8 Multiplication-Sign 10{sup 13} cm{sup -3}. - Abstract: This study reports the preparation of delafossite-CuCrO{sub 2} thin films were prepared on quartz substrates using sol-gel processing and post-annealing with an atmospheric pressure plasma torch. The films were first deposited on a quartz substrate by spin coating. The specimens were then annealed at 500 Degree-Sign C in air and post-annealed with an atmospheric pressure plasma torch with N{sub 2}-5% O{sub 2} at 650 Degree-Sign C for 20 min. The specimens annealed in air exhibited CuO and CuCr{sub 2}O{sub 4} phases. Post-annealing using an atmospheric pressure plasma torch obtained the pure CuCrO{sub 2} (delafossite, R3{sup Macron }m) phase. The binding energies of the Cu-2p{sub 3/2} and Cr-2p{sub 3/2} peaks of the CuCrO{sub 2} thin films were centered at 932.1 {+-} 0.2 eV and 576.1 {+-} 0.2 eV, which revealed the valence state of Cu{sup +} and Cr{sup 3+} in the films. The chemical composition of CuCrO{sub 2} thin films was close to the stoichiometry. As the CuCrO{sub 2} phase formed, the film surface began to exhibit agglomerate features and the cross-sectional morphology showed an equiaxed grain feature. The average transmittance of CuCrO{sub 2} thin films was approximately 66% in the visible region. The direct optical bandgap of CuCrO{sub 2} thin films was 3.08 eV, which is consistent with reported data in the literature. The

  5. Depolymerization of organosolv lignin to aromatic compounds over Cu-doped porous metal oxides

    NARCIS (Netherlands)

    Barta, Katalin; Warner, Genoa R.; Beach, Evan S.; Anastas, Paul T.

    2014-01-01

    Isolated, solvent-extracted lignin from candlenut (Aleurites moluccana) biomass was subjected to catalytic depolymerization in methanol with an added pressure of H-2, using a porous metal oxide catalyst (PMO) derived from a Cu-doped hydrotalcite-like precursor. The Cu-PMO was effective in converting

  6. Depolymerization of organosolv lignin to aromatic compounds over Cu-doped porous metal oxides

    NARCIS (Netherlands)

    Barta, Katalin; Warner, Genoa R.; Beach, Evan S.; Anastas, Paul T.

    2014-01-01

    Isolated, solvent-extracted lignin from candlenut (Aleurites moluccana) biomass was subjected to catalytic depolymerization in methanol with an added pressure of H-2, using a porous metal oxide catalyst (PMO) derived from a Cu-doped hydrotalcite-like precursor. The Cu-PMO was effective in converting

  7. Heteroepitaxial Cu2O thin film solar cell on metallic substrates.

    Science.gov (United States)

    Wee, Sung Hun; Huang, Po-Shun; Lee, Jung-Kun; Goyal, Amit

    2015-11-06

    Heteroepitaxial, single-crystal-like Cu2O films on inexpensive, flexible, metallic substrates can potentially be used as absorber layers for fabrication of low-cost, high-performance, non-toxic, earth-abundant solar cells. Here, we report epitaxial growth of Cu2O films on low cost, flexible, textured metallic substrates. Cu2O films were deposited on the metallic templates via pulsed laser deposition under various processing conditions to study the influence of processing parameters on the structural and electronic properties of the films. It is found that pure, epitaxial Cu2O phase without any trace of CuO phase is only formed in a limited deposition window of P(O2) - temperature. The (00l) single-oriented, highly textured, Cu2O films deposited under optimum P(O2) - temperature conditions exhibit excellent electronic properties with carrier mobility in the range of 40-60 cm(2) V(-1) s(-1) and carrier concentration over 10(16) cm(-3). The power conversion efficiency of 1.65% is demonstrated from a proof-of-concept Cu2O solar cell based on epitaxial Cu2O film prepared on the textured metal substrate.

  8. Single-Electron Detachment Cross Sections for Transition-Element Negative Ions Ti-,Cr-, Cu- in Collision with N2

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-Yi; ZHANG Xue-Mei; WU Shi-Min; LI Guang-Wu; LU Fu-Quan

    2004-01-01

    @@ Single-electron detachment (SED) cross sections for Cr- and Ti- in collision with N2 have been obtained in the energy region of 10-30 ke V, for the first time to our knowledge. In the present energy range, the magnitude of the Cr- +N2 and Fe- +N2 SED cross sections is larger than that of Cu- +N2. It is also found that the cross sections for Cr- and Ti- in collisions with N2 exhibit different dependences on anion impact velocity from that of Cu-.

  9. Impact of CrSiTi and NiSi on the Thermodynamics, Microstructure, and Properties of AlCoCuFe-Based High-Entropy Alloys

    Science.gov (United States)

    Wang, Xiao-Rong; Wang, Zhao-Qin; Lin, Tie-Song; He, Peng; Sekulic, Dusan P.

    2016-05-01

    Aiming to solve the problem of spontaneous combustion on titanium via electrospark deposition (ESD), two AlCoCuFe-based high-entropy alloys (HEAs), AlCoCuFe- x ( x = CrSiTi, NiSi), were produced by vacuum arc melting as electrodes in ESD process. The thermodynamic analysis of AlCoCuFe-based HEAs were carried out using the concept of mixing enthalpy matrix and a powerful thermodynamic calculation toolbox (HEA-Thermo-Calcu). The microstructure and mechanical properties of the two alloys were investigated. The AlCoCuFeCrSiTi alloy contains a body-centered cubic (BCC) phase and a face-centered cubic (FCC) phase. The AlCoCuFeNiSi alloy is composed of two BCC phases and an FCC phase. Addition of CrSiTi and NiSi to AlCoCuFe-based alloys makes the enthalpy of mixing to be sizably more negative than for the other AlCoCuFe-based HEAs. Notwithstanding the fact that the thermodynamic parameters do not agree with Yang's proposition, the two alloys form simple solid solutions. The electronegativity difference (Δ χ) favors a formation of the solid solution when Δχ ≤ 14.2. The hardness of AlCoCuFe- x ( x = CrSiTi, NiSi) alloys reaches 935 HV and 688 HV, respectively. The yield strength, fracture strength, and ultimate strain of AlCoCuFeNiSi are larger, i.e., 29, 30, and 45%, respectively, than those of the AlCoCuFeCrSiTi alloy.

  10. Interactions between salt marsh plants and Cu nanoparticles - Effects on metal uptake and phytoremediation processes.

    Science.gov (United States)

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

    2015-10-01

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

  11. Half-metallicity and tetragonal distortion in semi-Heusler alloy FeCrSe

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H. M., E-mail: smilehhm@163.com; Luo, S. J. [School of Science, Hubei University of Automotive Technology, Shiyan 442002 (China); Yao, K. L. [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); International Center of Materials Physics, The Chinese Academy of Science, Shenyang 110015 (China)

    2014-01-28

    Full-potential linearized augmented plane wave methods are carried out to investigate the electronic structures and magnetic properties in semi-Heusler alloy FeCrSe. Results show that FeCrSe is half-metallic ferromagnet with the half-metallic gap 0.31 eV at equilibrium lattice constant. Calculated total magnetic moment of 2.00μ{sub B} per formula unit follows the Slater-Pauling rule quite well. Two kinds of structural changes are used to investigate the sensitivity of half-metallicity. It is found that the half-metallicity can be retained when lattice constant is changed by −4.56% to 3.52%, and the results of tetragonal distortion indicate the half-metallicity can be kept at the range of c/a ratio from 0.85 to 1.20. The Curie temperature, cohesive energy, and heat of formations of FeCrSe are also discussed.

  12. Solid-state reactions during mechanical alloying of ternary Fe–Al–X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems: A review

    Energy Technology Data Exchange (ETDEWEB)

    Hadef, Fatma, E-mail: hadef77@yahoo.fr [Laboratoire de Recherche sur la Physico-Chimie des Surfaces et Interfaces, LRPCSI, Université 20 Août 1955, BP 26, Route d’El-Haddaiek, Skikda 21000 (Algeria); Département de Physique, Faculté des Sciences, Université 20 Août 1955, BP 26, Route d’El-Haddaiek, Skikda 21000 (Algeria)

    2016-12-01

    The last decade has witnessed an intensive research in the field of nanocrystalline materials due to their enhanced properties. A lot of processing techniques were developed in order to synthesis these novel materials, among them mechanical alloying or high-energy ball milling. In fact, mechanical alloying is one of the most common operations in the processing of solids. It can be used to quickly and easily synthesize a variety of technologically useful materials which are very difficult to manufacture by other techniques. One advantage of MA over many other techniques is that is a solid state technique and consequently problems associated with melting and solidification are bypassed. Special attention is being paid to the synthesis of alloys through reactions mainly occurring in solid state in many metallic ternary Fe–Al–X systems, in order to improve mainly Fe–Al structural and mechanical properties. The results show that nanocrystallization is the common result occurring in all systems during MA process. The aim of this work is to illustrate the uniqueness of MA process to induce phase transformation in metallic Fe–Al–X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems. - Highlights: • A review of state of the art on binary Fe–Al alloys was presented. • Structural and microstructural properties of MA ternary Fe–Al–X alloys were summerized. • MA process is a powerful tool for producing metallic alloys at the nanometer scale.

  13. Heavy Metal Resistances and Chromium Removal of a Novel Cr(VI)-Reducing Pseudomonad Strain Isolated from Circulating Cooling Water of Iron and Steel Plant.

    Science.gov (United States)

    Zhang, Jian-Kun; Wang, Zhen-Hua; Ye, Yun

    2016-12-01

    Three bacterial isolates, GT2, GT3, and GT7, were isolated from the sludge and water of a circulating cooling system of iron and steel plant by screening on Cr(VI)-containing plates. Three isolates were characterized as the members of the genus Pseudomonas on the basis of phenotypic characteristics and 16S rRNA sequence analysis. All isolates were capable of resisting multiple antibiotics and heavy metals. GT7 was most resistant to Cr(VI), with a minimum inhibitory concentration (MIC) of 6.5 mmol L(-1). GT7 displayed varied rates of Cr(VI) reduction in M2 broth, which was dependent on pH, initial Cr(VI) concentration, and inoculating dose. Total chromium analysis revealed that GT7 could remove a part of chromium from the media, and the maximum rate of chromium removal was up to 40.8 %. The Cr(VI) reductase activity of GT7 was mainly associated with the soluble fraction of cell-free extracts and reached optimum at pH 6.0∼8.0. The reductase activity was apparently enhanced by external electron donors and Cu(II), whereas it was seriously inhibited by Hg(II), Cd(II), and Zn(II). The reductase showed a K m of 74 μmol L(-1) of Cr(VI) and a V max of 0.86 μmol of Cr(VI) min(-1) mg(-1) of protein. The results suggested that GT7 could be a promising candidate for in situ bioremediation of Cr(VI).

  14. Solution growth of metal-organic complex CuTCNQ in small dimension interconnect structures

    Science.gov (United States)

    Demolliens, A.; Muller, Ch.; Müller, R.; Turquat, Ch.; Goux, L.; Deleruyelle, D.; Wouters, D. J.

    2010-11-01

    In this paper, we report two different elaboration routes to grow metal-organic complex CuTCNQ in liquid phase within small interconnect structures (i.e. via holes opened in SiO 2/SiC stack). The basic common idea relies on the formation of CuTCNQ material from the partial corrosion of a Cu bottom electrode by a TCNQ-based solution. The two solution growth methods are compared in terms of (i) via holes filling; (ii) local microstructure of CuTCNQ complex and (iii) quality of interface between CuTCNQ and copper metallic electrode. In the first route, in the reaction of the substrate with a TCNQ/copper salt solution in acetonitrile/toluene, a rapid formation of porous CuTCNQ complex is observed with an over-growth outside interconnect structures and many voids within via holes and at the interface with Cu layer. In contrast to this "mushroom-like" growth, the reaction of the substrate with a TCNQ solution in acetonitrile/2-butanone results in a "crystal-like" dense CuTCNQ complex within via holes and a CuTCNQ/Cu interface free of voids. In the latter case, satisfactory electrical performances are expected for future resistive switching memory devices.

  15. Microstructure and Wear Behavior of FeBSiNbCr Metallic Glass Coatings

    Institute of Scientific and Technical Information of China (English)

    Jiangbo Cheng; Xiubing Liang; Binshi Xu; Yixiong Wu

    2009-01-01

    In this paper, FeBSiNbCr metallic glass coatings were prepared onto AISI 1045 steel substrate by using wire arc spraying process. The phase and structure of the coating were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning election microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX). The microstructure of the coating consists of full amorphous phase. The coating has high hardness and low porosity. Full density and little oxides are detected in the coating. The mechanical properties, especially wear resistance, were investigated. The relationship between wear behavior and structure of the coatings were analyzed in detail. The main failure mechanism of the metallic glass coating is brittle breaking and fracture. The results indicate that FeBSiNbCr metallic glass coating has excellent resistance to abrasive wear.

  16. Al元素对AlxFeCrCoCuV高熵合金组织及摩擦性能的影响%Effects of Al Addition on Microstructure and Wear Properties of AlxFeCrCoCuV High-entropy Alloys

    Institute of Scientific and Technical Information of China (English)

    谢红波; 刘贵仲; 郭景杰; 周敏; 刘德飘; 毛炜乾

    2016-01-01

    采用非自耗电弧熔炼炉制备了AlxFeCrCoCuV(x=0,0.5,1.0)多组元高熵合金.用XRD,SEM,EDS和DSC技术探究了合金的微观组织,并测试了其硬度及耐磨性能.研究表明:随着Al的加入,Al0.5 FeCrCoCuV合金和Al1.0 FeCrCoCuV合金由FeCrCoCuV合金单一的BCC相变为由枝晶BCC和晶间FCC共同组成的双相组织;Al1.0 FeCrCoCuV合金的硬度大于Al0.5 FeCrCoCuV合金.合金的摩擦磨损测试主要以黏着磨损为主,合金的耐磨性能与硬度成正比.3种合金的摩擦因数都是随着时间的增加而减小,主要原因是随着摩擦时间的增加,合金表面生成了一层氧化物提高了合金的耐磨性能.%The AlxFeCrCoCuV (x= 0 ,0 .5 ,1 .0 )high-entropy alloys were fabricated by non-consuma-ble vacuum arc melting furnace,the characteristics including microstructure,hardness and wear prop-erties were examined by XRD,SEM,EDS and DSC.The results show that with the addition of aluminum,Al0.5 CrFeCoCuV and Al1.0 CrFeCoCuV alloys from single BCC phase of FeCrCoCuV to a transition duplex FCC/BCC phase;the hardness of Al1.0 CrFeCoCuV alloy is larger than Al0.5 CrFe-CoCuV alloy.The alloys show adhesive wear behaviors,the wear-resisting performance of the alloys is proportional to its hardness.With the increase of friction time,the three alloys generate a layer of oxide on the surface and attach to the friction surfaces to improve the wear resistance.

  17. Metal dynamics and tolerance of Typha domingensis exposed to high concentrations of Cr, Ni and Zn.

    Science.gov (United States)

    Mufarrege, M M; Hadad, H R; Di Luca, G A; Maine, M A

    2014-07-01

    Typha domingensis was exposed to a 100mgL(-1) Cr+100mgL(-1) Ni+100mgL(-1) Zn solution. Metal tolerance and metal accumulation in plant tissues and sediment were studied over time. Although removal rates were different, the three metals were efficiently removed from water. Leaf and root tissues showed high metal concentration. However, the sediment showed the highest accumulation. During the first hours of contact, metals were not only accumulated by sediment and roots but they were also taken up by the leaves in direct contact with the solution. Over time, metals were translocated from roots to leaves and vice versa. Metals caused growth inhibition and a decrease in chlorophyll concentration and affected anatomical parameters. Despite these sub-lethal effects, T. domingensis demonstrated that it could accumulate Cr, Ni and Zn efficiently and survive an accidental dump of high concentrations of contaminants in systems such as natural and constructed wetlands. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. [The effect of solid phase transformation on the metal-ceramic compatibility of Co-Cr alloy].

    Science.gov (United States)

    Wu, Zhikai; Xu, Sheng; Li, Ning

    2011-12-01

    To study the effect of solid phase transformation on the metal-ceramic compatibility of Co-Cr alloy during firing programs. 9 foils of Co-Cr and Ni-Cr alloy with the dimension of 25 mmx3 mmx0.5 mm were casted using lost wax technology respectively. Among them, 6 specimens were subjected to metal-ceramic bonding strength test (three point bending method), the ceramic layer of 3 specimens were removed for X-ray diffraction (XRD) analysis. One cylindrical specimen of each alloy was casted for the test of coefficient of thermal expansion, cooling curves were recorded. The metal-ceramic bonding strength of Ni-Cr, Co-Cr alloy was (49.1 +/- 3.40), (40.9 +/- 2.02) MPa respectively. There was significant difference between the two groups' bonding strength (P = 0.00). The coefficient of thermal expansion in the 20-500 degrees C interval of Ni-Cr and Co-Cr alloy was 13.9 x 10(-6), 13.8 x 10(-6) x K(-1) respectively. XRD analysis indicated that the microstructure of Ni-Cr alloy was austenite. While Co-Cr alloy was constituted by fcc phase, hcp phase and sigma phase. During the cooling procedure, the transformation of fcc phase to hcp phase and segregation of needle-like sigma phase intensify the linear contraction speed of Co-Cr alloy, which decreases the metal-ceramic adaptability.

  19. Facile synthesis of spinel CuCr{sub 2}O{sub 4} nanoparticles and studies of their photocatalytic activity in degradation of some selected organic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Bappi; Bhuyan, Bishal [Department of Chemistry, National Institute of Technology Silchar, Silchar, 788010, Assam (India); Purkayastha, Debraj Dhar, E-mail: debrajdp@yahoo.com [Department of Chemistry, National Institute of Technology Silchar, Silchar, 788010, Assam (India); Dhar, Siddhartha Sankar, E-mail: ssd_iitg@hotmail.com [Department of Chemistry, National Institute of Technology Silchar, Silchar, 788010, Assam (India); Behera, Satyananda [Department of Ceramic Engineering, National Institute of Technology Rourkela, Rourkela, 769008, Odisha (India)

    2015-11-05

    Copper chromite (CuCr{sub 2}O{sub 4}) spinel nanoparticle catalysts have been successfully synthesized employing urea assisted co-precipitation followed by calcination. The synthesized nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N{sub 2} adsorption-desorption isotherm (BET). The XRD pattern revealed formation of tetragonal body-centered CuCr{sub 2}O{sub 4} and TEM image showed quasi-spherical particles of size 5–35 nm. The photocatalytic activity of CuCr{sub 2}O{sub 4} was evaluated in degradation of some organic dyes such as methylene blue (MB), methyl orange (MO), and rhodamine B (RhB), without and with the assistance of H{sub 2}O{sub 2} under solar irradiation. The CuCr{sub 2}O{sub 4} photocatalysts showed high activity in degradation of RhB (93.6%) and MO (92.3%), but low activity in degradation of MB (80.6%). The catalyst reusability was tested by conducting the degradation of RhB dye with the spent catalyst and it was observed that the catalyst did not show any significant loss in its activity even after five cycles. - Highlights: • CuCr{sub 2}O{sub 4} nanoparticles were synthesized by urea assisted co-precipitation followed by calcination. • The XRD pattern revealed formation of tetragonal body-centered CuCr{sub 2}O{sub 4}. • The TEM images showed the material to be quasi-spherical in shape with sizes 5–35 nm. • CuCr{sub 2}O{sub 4} nanoparticles exhibited pronounced photocatalytic activity.

  20. Interlayer Segregation of Cu Atoms in Metal Multilayers

    Institute of Scientific and Technical Information of China (English)

    于广华; 李明华; 朱逢吾; 姜宏伟; 赖武彦; 柴春林

    2001-01-01

    The experimental results show that the exchange coupling field Hex of NiFe/FeMn for Ta/NiFe/FeMn/Ta multilayers is higher than that for the spin valve multilayers Ta/NiFe/Cu/NiFe/FeMn/Ta. The composition and chemical states at the surface of Ta(12 nm)/NiFe( 7 nm), Ta(12 nm)/NiFe(7 nm)/Cu(4 nm) and Ta(12 nm)/NiFe(7 nm)/Cu(3nm)/NiFe(5 nm) were studied by using x-ray photoelectron spectroscopy. The results show that no element from the underlayers floats out or segregates to the surface for Ta(12nm)/NiFe(7nm), Ta(12nm)/NiFe(7nm)/Cu(4nm). However, Cu atoms segregate to the surface of Ta(12nm)/NiFe(7nm)/Cu(3nm)/NiFe(5nm) multilayers, I.e. To the NiFe/FeMn interface for Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers. We believe that the presence of Cu atoms at the interface of NiFe/FeMn is one of the important factors which will cause the exchange coupling field Hex of Ta/NiFe/FeMn/Ta multilayers to be higher than that of Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers.

  1. The study of heavy metal pollution and accumulation in water, sediment, and fish tissue in Kizilirmak River Basin in Turkey.

    Science.gov (United States)

    Akbulut, Aydin; Akbulut, Nuray Emir

    2010-08-01

    The accumulation of heavy metals such as Pb, Hg, Co, Cr, Cu, Zn, and Br were determined in water, sediment, muscle, and gill of three fish species (Leuciscus cephalus, Capoeta tinca, Capoeta capoeta) which were collected in Kizilirmak River Basin (Delice River). The metal concentration showed a general trend of Br>Zn>Pb>Cr>Cu>Hg>Co in water and Cr>Zn>Pb>Cu>Co>Hg>Br in sediment samples while Zn>Cu>Pb>Br>Cr>Hg>Co were in muscle and Zn>Pb>Cu>Cr>Br>Hg>Co were in the gill tissue.

  2. Magnetic properties and spin polarization of Ru doped half metallic CrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    West, Kevin G.; Dao, Nam N. H.; Lu, Jiwei, E-mail: jl5tk@virginia.edu [Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Osofsky, Michael; Mazin, I. I. [Naval Research Laboratory, Washington, DC 20375 (United States); Wolf, Stuart A. [Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2015-07-06

    Chromium dioxide (CrO{sub 2}) is a half metal that is of interest for spintronic devices. It has not been synthesized through traditional physical vapor deposition (PVD) techniques because of its thermodynamic instability in low oxygen pressures. Epitaxial thin films of Ru doped tetragonal rutile CrO{sub 2} were synthesized by a PVD technique. The as-deposited Ru{sub x}Cr{sub 1−x}O{sub 2} was ferrimagnetic with the saturation magnetization moment showing a strong dependence on the Ru concentration. Curie temperature as high as 241 K has been obtained for ∼23 at. % Ru. The Ru substitution increased the electrical conductivity by increasing the minority spin concentration. The spin polarization was found to be as high as 70% for 9 at. % Ru and decreased to ∼60% with Ru concentrations up to ∼44 at. %, which is determined by the Fermi velocities of the majority and minority spins. First principle calculations were performed to understand the effect of Ru content on the properties of CrO{sub 2}. The PVD processes of Ru doped CrO{sub 2} could lead to the practical applications of the high spin polarization of CrO{sub 2} in spintronic devices.

  3. Crystallization behavior of Zr62Al8Ni13Cu17 Metallic Glass

    Directory of Open Access Journals (Sweden)

    Jo Mi Sun

    2017-06-01

    Full Text Available The crystallization behavior has been studied in Zr62Al8Ni13Cu17 metallic glass alloy. The Zr62Al8Ni13Cu17 metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson-Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.

  4. Coexistence of metallic and nonmetallic charge transport in PrBa2Cu3O7

    Science.gov (United States)

    Lee, Mark; Suzuki, Y.; Geballe, T. H.

    1995-06-01

    Magnetotransport measurements on highly oriented thin films of PrBa2Cu3O7 demonstrate a unique coexistence of nonmetallic hopping conduction with metallic Boltzmann transport. At high temperature (T>10 K) hopping transport dominates, but when the inelastic conduction freezes out at low temperature, metallic behavior can be distinguished. The hopping conduction is assigned to the CuO2 planes, while the Boltzmann transport arises from the CuO chain structure, in agreement with recent electronic-structure calculations.

  5. Study of environmental contamination in growth tree rings of Copaifera Langsdorfii by SR-TXRF: evaluation of Cr, Ni, Cu, Zn and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Bruna Fernanda; Moreira, Silvana, E-mail: bffaria@yahoo.com.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Saneamento e Ambiente; Vives, Ana Elisa S. de, E-mail: aesvives@unimep.b [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo

    2009-07-01

    Some arboreal species present annual cycles of growth and sleeping, registered in the log by different anatomical structures - the growth rings. With the objective of verifying the industrial activity in the city of Bauru, SP samples were submitted to a quantitative analysis in order to verify the bio-accumulation of metals. For that Synchrotron Radiation Total Reflection X-Ray Fluorescence was used. Samples of Copaifera Langsdorfii (Copaiba) were collected close to Municipal Forest of Bauru, SP located at 200m of distance of a disabled company of energy accumulators (batteries) known by receiving several penalties of CETESB due disagreement with the environmental legislation. Through the quantification of the elements Cr, Ni, Cu, Zn and Pb in the annual growth rings were possible to verify the influence of the battery industry in the local pollution. The temporal variation of Pb showed that after the interdiction of the battery industry the concentrations are close to the reference value, but in the periods previous to the industry interdiction the Pb concentrations were above the reference value. For Cr, 46% of the samples presented superior concentration to the reference value. Zinc presented larger concentration in the period from 1996 to 1998, reaching 1383 mug g{sup -1}. For Cu the concentrations were higher than the reference value in almost all periods analyzed, that is, from 1969 to 2004. On the other hand Ni presented great oscillation in its concentration, and the highest values were observed in the period from 1969 to 1971 and from 1999 to 2001, reaching 87 mug g{sup -1}. (author)

  6. Fabrication of dye sensitized solar cell using Cr doped Cu-Zn-Se type chalcopyrite thin film

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, D. Paul; Venkateswaran, C. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-600 025 (India); Ganesan, S.; Suthanthiraraj, S. Austin; Maruthamuthu, P. [Department of Energy, University of Madras, Guindy Campus, Chennai 600 025 (India); Kovendhan, M. [Department of Physics, Presidency College, Chennai 600 005 (India)

    2011-09-15

    Chalcopyrites are a versatile class of semiconductors known for their potential in photovoltaic applications. Considering the well established CuInSe{sub 2} as a prototype system, a new compound of the chalcopyrite type, Cu{sub 1-x}Zn{sub 1-y}Se{sub 2-{delta}}, by replacing In with Zn, has been prepared (both undoped and 2% Cr doped) by the metallurgical method. Thin films have been deposited by the thermal evaporation technique using the stabilized polycrystalline compounds as charge. Structural, compositional, morphological, and optical properties of the films are analyzed and reported. Use of these films as electrodes in dye sensitized solar cell (DSSC) is demonstrated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. PROPERTIES OF POLYMER SUPPORTED Ni-Cu BIMETALLIC CATALYSTS PREPARED BY SOLVATED METAL ATOM IMPREGNATION

    Institute of Scientific and Technical Information of China (English)

    WU Shihua; ZHU Changying; HUANG Wenqiang

    1996-01-01

    D-72 resin supported nickel-copper catalysts prepared by solvated metal atom impregnation (SMAI) were studied by magnetic measurements and X-ray photoelectron spectroscopy (XPS). The Ni particles on the catalysts are very highly dispersed and display superparamagnetic behaviour. Ni-Cu alloy clusters were found to be formed. The surface compositions are different from the bulk concentrations. In contrast with the surface enrichment in copper generally observed on conventional Ni-Cu catalysts, the surfaces of these catalysts are enriched in nickel. The nickel is in both zero and valent states, while copper is mainly in metallic state. Catalytic data show that the formation of Ni-Cu alloy clusters has a profound effect on the catalytic activities of the catalysts in the hydrogenation of furfural. The activity of the Ni:Cu ratio of one bimetallic catalysts is much higher than that of the Ni or Cu monometallic catalyst.

  8. Final report on in-reactor creep-fatigue deformation behaviour of a CuCrZr alloy: COFAT 1

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Tähtinen, S.; Moilanen, P.

    At present, practically nothing is known about the deformation behaviour of materials subjected simultaneously to external cyclic force and neutron irradiation. The main objective of the present work is to determine experimentally the mechanical response and resulting microstructural changes in CuCrZr...... discussed. The main conclusion emerging from the limited amount of present results is that neither the irradiation nor the duration of the holdtime have any significant effect on the lifetime (in terms of number of cycle to failure) of the material....

  9. Frequency and Field Dependences of Giant Magneto-Impedance Effect in Sandwiched FeCuCrVSiB Films

    Institute of Scientific and Technical Information of China (English)

    DAI You-Yong; XIAO Shu-Qin; LIU Yi-Hua; ZHANG Lin; WU Hou-Zheng; ZHANG Yan-Zhong

    2001-01-01

    The giant magneto-impedance (GMI) effect has been investigated in sandwiched FeCuCrVSiB films annealed at 300 ℃ for 1.5 h. The frequency and field dependences of the GMI have been observed in the frequency range from 50 kHz to 13 MHz. The GMI ratio increases at first with increasing frequency, and reaches its maximum value of 136% at a very low characteristic frequency of about 4 MHz, and then decreases with further increasing frequency. These superior properties are related to the special structure of the sandwiched films.

  10. Vacuum Brazing of TiAl Based Alloy with 40Cr Steel

    Institute of Scientific and Technical Information of China (English)

    周昀; 薛小怀; 吴鲁海; 楼松年

    2004-01-01

    The vacuum brazing of TiAl based alloy with 40Cr steel was investigated using Ag-Cu-Ti filler metal.The experimental results show that the Ag, Cu, Ti atoms in the filler metal and the base metal inter-diffuse toward each other during brazing and react at the interface to form an inter-metallic AlCu2Ti compound which joins two parts to produce a brazing joint with higher strength.

  11. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    Energy Technology Data Exchange (ETDEWEB)

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  12. Heavy metal tolerance (Cr, Ag and Hg in bacteria isolated from sewage

    Directory of Open Access Journals (Sweden)

    Agostinho A. de Lima e Silva

    2012-12-01

    Full Text Available Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr, silver (Ag and mercury (Hg. Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%. Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerantBacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr. Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria.

  13. Heavy metal tolerance (Cr, Ag AND Hg) in bacteria isolated from sewage

    Science.gov (United States)

    Lima de Silva, Agostinho A.; de Carvalho, Márcia A. Ribeiro; de Souza, Sérgio A. L; Dias, Patrícia M. Teixeira; da Silva Filho, Renato G.; de Meirelles Saramago, Carmen S.; de Melo Bento, Cleonice A.; Hofer, Ernesto

    2012-01-01

    Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr), silver (Ag) and mercury (Hg). Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%). Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerant Bacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr). Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria. PMID:24031994

  14. Copper-Metalized GaAs pHEMT with Cu/Ge Ohmic Contacts

    OpenAIRE

    E. V. Anichenko; Arykov, V. S.; Erofeev, E. V.; Kagadei, V. A.

    2012-01-01

    The fully Cu-metalized GaAs pHEMT using developed Cu/Ge-based ohmic contacts and T-gate Ti/Mo/Cu with length of the 150 nm has been successfully fabricated for the high-frequency applications. The fabricated Cu-metalized pHEMT has a maximum drain current of 360 mA/mm, an off-state gate-drain breakdown of 7 V, and a transconductance peak of 320 mS/mm at Vds=3 V. The maximum stable gain value was about 15 dB at frequency 10 GHz. The current gain cutoff frequency of the copper-metalized device ...

  15. Microstructure and Strength of Brazed Joints of Ti3Al Base Alloy with Cu-P Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Peng HE; Jicai FENG; Heng ZHOU

    2005-01-01

    Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173~1273 K for 60~1800 s. When products are brazed, the optimum brazing parameters are as follows: brazing temperature is 1215~1225 K; brazing time is 250~300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu (Ti3Al(Cu)) formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al(Cu) and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interfacial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al(Cu)/TiCu/Cu3P/Cu solid solution (Cu3P)/Cu3P/TiCu/Ti3Al(Cu)/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu+Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity K0 of reaction layer TiCu+Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 k J/mol and 0.0821 m2/s, respectively, and growth formula was y2=0.0821exp(-34421.59/T)t.Careful control of the growth for the reaction layer TiCu+Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu+Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.

  16. Effect of Ti content on structure and properties of Al{sub 2}CrFeNiCoCuTi{sub x} high-entropy alloy coatings

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, X.W., E-mail: fallenrain922@163.com [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048 (China); Sichuan College of Architectural Technology, Deyang 618000 (China); Zhang, Y.P. [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048 (China); Liu, C.G. [Sichuan College of Architectural Technology, Deyang 618000 (China)

    2014-02-05

    Highlights: • Al{sub 2}CrFeNiCoCuTi{sub x} high-entropy alloy coatings were prepared by laser cladding. • Al{sub 2}CrFeNiCoCuTi{sub x} coatings show excellent corrosion resistance and wear resistance. • Al{sub 2}CrFeNiCoCuTi{sub 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{sub 2}CrFeNiCoCuTi{sub 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{sub 2}CrFeNiCoCuTi{sub 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{sub 2}CrFeNiCoCuTi{sub 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{sub 2}CrFeNiCoCuTi{sub 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{sub 2}CrFeCoCuNiTi{sub x} high-entropy alloy coatings enhanced in 0.5 mol/L HNO{sub 3} solution. Compared with Q235 steel, the relative wear resistance of Al{sub 2}CrFeCoCuNiTi{sub x} high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti{sub 0.0} high-entropy alloy is a kind of soft magnetic materials.

  17. Preparation and characterization of CuCrO{sub 2}/TiO{sub 2} heterostructure photocatalyst with enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Dehua, E-mail: xiongdehua2010@gmail.com [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China); National Engineering Laboratory for Fiber Optic Sensing Technology, Wuhan University of Technology, Wuhan 430070 (China); Chang, Haimei; Zhang, Qingqing; Tian, Shouqin; Liu, Baoshun [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China); Zhao, Xiujian, E-mail: opluse@whut.edu.cn [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China)

    2015-08-30

    Graphical abstract: - Highlights: • p-CuCrO{sub 2}/n-TiO{sub 2} heterostructure photocatalysts were fabricated for the first time. • The p–n heterojunctions were formed between CuCrO{sub 2} nanoparticle and TiO{sub 2} nanorod. • The degradation activity of CuCrO{sub 2}/TiO{sub 2} was much higher than that of pure TiO{sub 2}. • CuCrO{sub 2}/TiO{sub 2} has better separation efficiency of photogenerated electron and hole. - Abstract: A series of novel p-type CuCrO{sub 2}/n-type TiO{sub 2} heterostructure photocatalysts were fabricated for the first time by depositing CuCrO{sub 2} nanoparticles on TiO{sub 2} nanorod-array film through a facile spin-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photocurrent response were employed to characterize the as-synthesized composites. The photocatalytic activity of CuCrO{sub 2}/TiO{sub 2} for degradation of methylene blue (MB) aqueous solution was much higher than pure TiO{sub 2}, which could be ascribed to the formation of p–n heterojunctions between CuCrO{sub 2} nanoparticles and TiO{sub 2} nanorods. In particular, the best degradation efficiency of CuCrO{sub 2}/TiO{sub 2} heterojunction was 85.3%, about 1.14 times higher than pure TiO{sub 2} (74.6%), which could be attributed to their high separation efficiency of photogenerated electrons and holes. It is expected this strategy of p–n junction for enhancing photocatalytic activity can have considerable impact to promote the development of high efficient photocatalyst and industrial application for degrading pollutant, treating waste water and other environmental protection fields.

  18. Effect of Cu2+ , Cd2+ and Cr6+ Stress on the Anti-oxidative Enzyme Activities in Danio rerio%Cu2+、Cd2+、Cr6+胁迫对斑马鱼抗氧化酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    宋志慧; 王庆伟

    2011-01-01

    [ Objective ] The aim was to study the effect of Cu2+, Cd2+ and Cr6+ on the anti-oxidative enzyme activities in Danio rerio, and discuss the toxicity effect of heavy metal on Danio rerio. [ Method] Danio rerio was viewed as model organism, semi-static toxicity test was used in domestication and experiments of Danio rerio, the effects of Cu2+ , Cd2+ and Cr6+ on superoxide dismutase (SOD), peroxiclase (POD) and catalase (CAT) of it were discussed. [ Result] At 1 d, effects of Cu2+ stress on SOD in Danio rerio was induction effect, and the stress on POD was inhibition-induction-inhibition effect, and stress on CAT was induction effect. At 7 d, effects of Cu2+ stress on SOD in Danio rerio was induction effect, and stress on POD was inhibition effect, and stress on CAT was inhibition effect. At 1 and 7 d, effects of Cd2+ stress on SOD in Danio rerio were all induction effect, and stress on POD and CAT were all inhibition effect. Moreover, the enzyme activities were changed markedly significantly at from 1 to 7d. [ Conclusion] Cu2+ , Cd2+ and Cr6+ single stress on the anti-oxidative enzyme activities in Danio rerio were changed markedly. In short time and low-concentration exposure, Cr6+ toxicity was the most significantly; in short time and high-concentration exposure, Cd2+ toxicity was the most the most significantly; in long time exposure, Cu2+ toxicity was the most significantly.The study could provide references for heavy metal pollution on the aquatic organism toxicity mechanism.%[目的]研究Cu、Cd、Cr对斑马鱼抗氧化酶活性影响,探讨重金属对斑马鱼毒性大小.[方法]以斑马鱼为模式生物,采用半静态法对斑马鱼进行驯养和试验,测定Cu、Cd和Cr对超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性影响.[结果]Cu暴露1d胁迫斑马鱼SOD和CAT为诱导效应,胁迫POD为抑制-诱导-抑制效应,Cu暴露7 d胁迫斑马鱼SOD为诱导效应,胁迫POD和CAT为抑制效应;Cu和Cr暴露1 d和7 d

  19. CuCr2O4 Spinel Ceramic Pigments Synthesized by Sol-Gel Self-Combustion Method for Solar Absorber Coatings

    Science.gov (United States)

    Ma, Pengjun; Geng, Qingfen; Gao, Xianghu; Yang, Shengrong; Liu, Gang

    2016-07-01

    A series of CuCr2O4 spinel ceramic pigments have been successfully synthesized via a facile and cost-effective sol-gel self-combustion method. The reaction mechanism was systematically studied using the corresponding characterization technologies. The results suggested that CuCr2O4 spinel ceramic pigments could be obtained at annealing temperature of 600 °C for 1 h, and the size, morphology, and crystallinity of CuCr2O4 spinel were greatly influenced by the annealing temperature. The as-burnt powder and CuCr2O4 spinel ceramic pigment were then employed to fabricate thickness sensitive spectrally selective (TSSS) paint coatings by a convenient spray-coating technique. The results revealed that spectral selectivity of TSSS paint coatings based on CuCr2O4 spinel ceramic pigments was much better than that of paint coatings based on the as-burnt powders. Furthermore, the effect of surface features of TSSS paint coatings on its optical property and hydrophobicity was investigated in detailed.

  20. Sub-micron-sized delafossite CuCrO$_2$ with different morphologies synthesized by nitrate–citric acid sol–gel route

    Indian Academy of Sciences (India)

    SATISH BOLLOJU; RADHAKRISHNAN SRINIVASAN

    2017-02-01

    Currently, copper chromium oxide crystallizing in delafossite structure attracts huge research interest due to its versatile applications arising from its layered structure. In this work, delafossite CuCrO$_2$ was synthesized by sol–gel method from their respective hydrated nitrate salts with citric acid as a chelating agent. The phase formation temperature was found to be between 750 and 775$^{\\circ}$C. At 750$^{\\circ}$C, the partial formation of delafossite CuCrO$_2$spheres with particle size in nano-regime was observed in the midst of platelets of spinel CuCr$_2$O$_4$. A green coloured powder with particle size 125–350 nm exhibiting distorted spheres was obtained at 775$^{\\circ}$C. The increase in temperature has a profound impact on the particle size, morphology and the optical properties of CuCrO$_2$. The X-ray powder diffraction studies revealed the formation of 3R-CuCrO$_2$ phase (rhombohedral, space group R-3m) as amajor product in the temperature range 775–1000$^{\\circ}$C. The unit cell parameters were found to be $a = b = 2.9711$ \\AA and $c = 17.0723$ \\AA at 1000$^{\\circ}$C. Scanning electron micrographs illustrated the different morphologies from spheres to hexagonal form via distorted spheres and cubes. The UV–Vis diffuse reflectance spectra measured for the powders exhibited semiconductor characteristics with an interesting size-related and temperature-dependent bandgap.

  1. An interatomic potential for studying CuZr bulk metallic glasses

    DEFF Research Database (Denmark)

    Paduraru, Anca; Kenoufi, Abdel; Bailey, Nicholas

    2007-01-01

    -scale deformation events and may furthermore involve localization through formation of shear bands. In this paper, an Effective Medium Theory (EMT) potential optimized for modeling the mechanical and thermodynamic properties of CuZr bulk metallic glass is studied. The late transition metals crystallizing in close...

  2. 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.

  3. Microstructure, thermodynamics and compressive properties of AlCoCrCuMn-x (x=Fe, Ti) high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaoqin, E-mail: wzqpapers@126.com [School of Railway Technology, Lanzhou Jiaotong University, Lanzhou 730010 (China); Wang, Xiaorong [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730010 (China); Yue, Hui [School of Railway Technology, Lanzhou Jiaotong University, Lanzhou 730010 (China); Shi, Guangtian; Wang, Shunhua [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730010 (China)

    2015-03-11

    Two equiatomic high-entropy alloys (HEAs), AlCoCrCuMnFe and AlCoCrCuMnTi, were produced by vacuum arc melting. Their microstructure, thermodynamics and mechanical properties were investigated in as-cast condition. The AlCoCrCuMnFe alloy is comprised of a face centered cubic (FCC) phase and two body centered cubic (BCC) phases, while the AlCoCrCuMnTi alloy consists of the intermetallics-base solid solution (AlCu{sub 2}Mn-like phase) besides a FCC phase and two BCC phases. Through analyzing the thermodynamics of equiatomic multicomponent alloys, two parameters, k{sub n} and φ, were proposed. The parameter k{sub n} is a function of n (n – the number of the components in an alloy system), while φ is defined as a parameter of T{sub sum} over |H{sub sum}| (T{sub sum} – the sum of every elemental melting point in an alloy system, |H{sub sum}| – the sum of mixing enthalpies of different pairs of alloying elements). φ≥1.1/k{sub n} is equivalent to Ω≥1.1 proposed by Yang to predict high entropy stabilized solid solution in equiatomic multicomponent alloys and more convenient to calculate. Compressive properties of the two HEAs together with their hardness have been investigated. Comparing to AlCoCrCuMnFe alloy, AlCoCrCuMnTi alloy has higher Vickers hardness, yield strength and compressive strength, but lower ultimate strain.

  4. Plastic deformation behavior of Fe–Co–B–Si–Nb–Cr bulk metallic glasses under nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.T.; Hong, S.H.; Lee, C.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, J.M., E-mail: jinman_park@hotmail.com [Materials Research Center, Samsung Advanced Institute of Technology (SAIT), San 14-1, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of); Kim, T.W.; Lee, W.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Yim, H.I. [Department of Physics, Sookmyung Women’s University, Hyochangwongil 52, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Kim, K.B., E-mail: kbkim@sejong.ac.kr [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2014-02-25

    Highlights: • Additional Cr modulation of atomic structure of Fe-Co-B-Si-Nb BMGs. • An amount of free volume characterized by a combination of nanoindentation and AFM. • Free volume determined by height measurement of AFM after nanoindentation. -- Abstract: In this work, we investigate the effect of Cr addition on thermal properties and indentation behavior of Fe{sub 52}Co{sub 20−x}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub x} alloys with x = 0, 1, 3 and 5 at.%, respectively. Among all studied alloys, the Fe{sub 52}Co{sub 17}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub 3} bulk metallic glass (BMG) exhibits the highest thermal stability with large supercooled liquid region of 40 K and the pronounced plastic deformation features which is serrated flow (pop-in event) and significant pile-up of materials around indents. This demonstrates that the appropriate addition of Cr in Fe-based BMG can induce the internal atomic structure modulation and promote the mechanical softening, which are discussed in terms of free volume concept.

  5. Improved ductility of Cu64Zr36 metallic glass/Cu nanocomposites via phase and grain boundaries

    Science.gov (United States)

    Jian, W. R.; Wang, L.; Li, B.; Yao, X. H.; Luo, S. N.

    2016-04-01

    We investigate tensile deformation of metallic glass/crystalline interpenetrating phase nanocomposites as regards the effects of specific area of amorphous/crystalline phase interfaces, and grain boundaries. As an illustrative case, large-scale molecular dynamics simulations are performed on Cu64Zr36 metallic glass/Cu nanocomposites with different specific interface areas and grain boundary characteristics. Plastic deformation is achieved via shear bands, shear transformation zones, and crystal plasticity. Three-dimensional amorphous/crystalline interfaces serve as effective barriers to the propagation of shear transformation zones and shear bands if formed, diffuse strain localizations, and give rise to improved ductility. Ductility increases with increasing specific interface area. In addition, introducing grain boundaries into the second phase facilitates crystal plasticity, which helps reduce or eliminate mature shear bands in the glass matrix.

  6. PENGOLAHAN LIMBAH Cr(VI DAN FENOL DENGAN FOTOKATALIS SERBUK TiO2 DAN CuO/TiO2

    Directory of Open Access Journals (Sweden)

    Slamet Slamet

    2011-07-01

    Full Text Available Studi tentang pengolahan limbah Cr(VI dan fenol secara fotokatalisis telah dilakukan dengan fotokatalis TiO2 dan CuO/TiO2. Katalis CuO/TiO2 dipreparasi dengan cara impregnasi terhadap TiO2 Degussa P25 menggunakan larutan garam tembaga yang berasal dari berbagai jenis prekursor. Komposisi Cu dalam katalis divariaskani dari 0,2% hingga 5%. Fotokatalis tersebut kemudian dikarakterisasi DRS (Diffuse Reflectance Spectroscopy dan XRD (X-Ray Diffraction. Aktivitas fotokatalis diuji dengan menggunakan sistem reaktor slurry yang bekerja secara batch dan dilengkapi dengan 6 lampu UV black light selama 5 jam, kemudian hasilnya dianalisis dengan UV-VIS Spectrophotometer. Hasil karakterisasi DRS menunjukan bahwa penambahan CuO dari 1% hingga 5% ke dalam TiO2 dapat meningkatkan pita absorbansi katalis dari 398 hingga 413 nm dan menurunkan band gap dari 3,2 hingga 2,58 eV. Hasil karakterisasi XRD menunjukan adanya struktur kristal anatase dan rutil dalam katalis TiO2 dan CuO/TiO2, sementara struktur kristal CuO muncul pada katalis CuO/TiO2 yang dipreparasi dengan prekursor Cu-Asetat dan Cu-Nitrat. Fotokatalis 0,2% CuO/TiO2 dari prekursor Cu-Asetat memiliki aktivitas optimal yang mereduksi Cr(VI 99,67% dan mendegradasi fenol 97,16%. Sementara jika kedua limbah tersebut diolah secara simultan, katalis TiO2 Degussa P25 memiliki aktivitas yang paling tinggi dengan meningkatkan konversi reduksi Cr(VI menjadi 100% dan menurunkan konversi degradasi fenol menjadi 93,81% dengan waktu reaksi 5 jam.

  7. Magnetoelectric properties of multiferroic CuCrO2 studied by means of ab initio calculations and Monte Carlo simulations

    Science.gov (United States)

    Albaalbaky, Ahmed; Kvashnin, Yaroslav; Ledue, Denis; Patte, Renaud; Frésard, Raymond

    2017-08-01

    Motivated by the discovery of multiferroicity in the geometrically frustrated triangular antiferromagnet CuCrO2 below its Néel temperature TN, we investigate its magnetic and ferroelectric properties using ab initio calculations and Monte Carlo simulations. Exchange interactions up to the third nearest neighbors in the a b plane, interlayer interaction, and single ion anisotropy constants in CuCrO2 are estimated by a series of density functional theory calculations. In particular, our results evidence a hard axis along the [110] direction due to the lattice distortion that takes place along this direction below TN. Our Monte Carlo simulations indicate that the system possesses a Néel temperature TN≈27 K very close to the ones reported experimentally (TN=24 -26 K). Also we show that the ground state is a proper-screw magnetic configuration with an incommensurate propagation vector pointing along the [110] direction. Moreover, our work reports the emergence of spin helicity below TN which leads to ferroelectricity in the extended inverse Dzyaloshinskii-Moriya model. We confirm the electric control of spin helicity by simulating P -E hysteresis loops at various temperatures.

  8. ETAAS method for the determination of Cd, Cr, Cu, Mn and Se in blood fractions and whole blood

    Energy Technology Data Exchange (ETDEWEB)

    Prohaska, C.; Pomazal, K.; Steffan, I. [Technische Univ., Vienna (Austria). Inst. fuer Analytische Chemie

    2000-11-01

    An electrothermal atomic absorption method (ETAAS) for the direct determination of trace elements (Cd, Cr, Cu, Mn, Se) both in blood fractions (erythrocytes, plasma and lymphocytes) and whole blood was developed. Zeeman background correction and graphite tubes with L'vov platforms were used. Samples were diluted with HNO{sub 3}/Triton X-100 and pipetted directly into the graphite tube. Ashing, pretreatment and atomization steps were optimized carefully for the different fractions and elements applying different matrix modifiers for each element. For the lymphocyte fraction a multi-fold injection technique was applied. Low detection limits of the ETAAS method (Cd 0.13 {mu}g/L, Cr 0.11 {mu}g/L, Cu 0.52 {mu}g/L, Mn 0.13 {mu}g/L, Se 0.7 {mu}g/L of whole blood) combined with small quantities of sample necessary for analysis allow determination of trace elements in this matrix. Verification of possible differences in the trace element status of humans was performed with statistical significance (P < 0.05). In addition, a contribution to the determination of normal values of essential elements was achieved. The method was applied for determination of trace elements in human blood and blood fractions of two groups (n = 50) different in health status. (orig.)

  9. Multiferroic CuCrO₂ under high pressure: In situ X-ray diffraction and Raman spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Alka B., E-mail: alkagarg@barc.gov.in; Mishra, A. K.; Pandey, K. K.; Sharma, Surinder M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-10-07

    The compression behavior of delafossite compound CuCrO₂ has been investigated by in situ x-ray diffraction (XRD) and Raman spectroscopic measurements up to 23.2 and 34 GPa, respectively. X-ray diffraction data show the stability of ambient rhombohedral structure up to ~23 GPa. Material shows large anisotropy in axial compression with c-axis compressibility, κ{sub c} = 1.26 × 10⁻³(1) GPa⁻¹ and a-axis compressibility, κ{sub a} = 8.90 × 10⁻³(6) GPa⁻¹. Our XRD data show an irreversible broadening of diffraction peaks. Pressure volume data when fitted to 3rd order Birch-Murnaghan equation of state give the value of bulk modulus, B₀ = 156.7(2.8) GPa with its pressure derivative, B₀{sup ’} as 5.3(0.5). All the observed vibrational modes in Raman measurements show hardening with pressure. Appearance of a new mode at ~24 GPa indicates the structural phase transition in the compound. Our XRD and Raman results indicate that CuCrO{sub 2} may be transforming to an ordered rocksalt type structure under compression.

  10. Tribological Properties of AlCrCuFeNi2 High-Entropy Alloy in Different Conditions

    Science.gov (United States)

    Liu, Yong; Ma, Shengguo; Gao, Michael C.; Zhang, Chuan; Zhang, Teng; Yang, Huijun; Wang, Zhihua; Qiao, Junwei

    2016-07-01

    In order to understand the environmental effect on the mechanical behavior of high-entropy alloys, the tribological properties of AlCrCuFeNi2 are studied systematically in dry, simulated rainwater, and deionized water conditions against the Si3N4 ceramic ball at a series of different normal loads. The present study shows that both the friction and wear rate in simulated rainwater are the lowest. The simulated rainwater plays a significant role in the tribological behavior with the effect of forming passive film, lubricating, cooling, cleaning, and corrosion. The wear mechanism in simulated rainwater is mainly adhesive wear accompanied by abrasive wear as well as corrosive wear. In contrast, those in dry condition and deionized water are abrasive wear, adhesive wear, and surface plastic deformation. Oxidation contributes to the wear behavior in dry condition but is prevented in liquid condition. In addition, the phase diagram of Al x CrCuFeNi2 is predicted using CALPHAD modeling, which is in good agreement with the literature report and the present study.

  11. Solid-state reactions during mechanical alloying of ternary Fe-Al-X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems: A review

    Science.gov (United States)

    Hadef, Fatma

    2016-12-01

    The last decade has witnessed an intensive research in the field of nanocrystalline materials due to their enhanced properties. A lot of processing techniques were developed in order to synthesis these novel materials, among them mechanical alloying or high-energy ball milling. In fact, mechanical alloying is one of the most common operations in the processing of solids. It can be used to quickly and easily synthesize a variety of technologically useful materials which are very difficult to manufacture by other techniques. One advantage of MA over many other techniques is that is a solid state technique and consequently problems associated with melting and solidification are bypassed. Special attention is being paid to the synthesis of alloys through reactions mainly occurring in solid state in many metallic ternary Fe-Al-X systems, in order to improve mainly Fe-Al structural and mechanical properties. The results show that nanocrystallization is the common result occurring in all systems during MA process. The aim of this work is to illustrate the uniqueness of MA process to induce phase transformation in metallic Fe-Al-X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems.

  12. Optical Limiting Properties of Ag-Cu Metal Alloy Nanoparticles Analysis by using MATLAB

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Hua; LI Hui-Qing; LU Jian-Duo; WANG Ru-Wu

    2011-01-01

    Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source.Third-order nonlinear optical properties of the nanoparticles were measured at 1064nm excitations using the Z-scan technique.Curve fitting analysis,based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments,is used.The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064 nm.Recently,increasing attention has been focused on the third-order nonlinear susceptibility and the photorefractive effect of noble-metal clusters embedded in dielectric matrices.[1-3] Third-order nonlinearities of metal/dielectric composite materials are influenced not only by the type and size of the embedded metal clusters,but also by the dielectric constant,thermal conductivity and heat capacity of the dielectric matrices.[4-6] Amongst the nanoparticles studied earlier,high nonlinear absorption and nonlinear refraction coefficients were found in copper and copper containing nanomaterials.[7,8] For silver,the nonlinear refractive index γ changes from positive to negative upon the growth of clusters.[9] Potential applications of optical limiters in the protection of sensors from intense laser pulses have motivated great efforts to design new nonlinear optical systems.[10]%Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source. Third-order nonlinear optical properties of the nanoparticles were measured at 1064 nm excitations using the Z-scan technique. Curve fitting analysis, based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments, is used. The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064 nm.

  13. Characterization of laser-produced plasma ions of various metals and their effect on the optical properties of the CR-39 polymer

    Science.gov (United States)

    Ali, Dilawar; Butt, M. Z.; Naseem, S.

    2013-01-01

    The laser-produced plasma (LPP) ions of various metals (Mo, Ni, Cu, Ti and Zn) was implanted in CR-39 polymer, and their influence on its optical properties was investigated. The plasma of these metals was produced using 200 shots of a Q-switched Nd:YAG pulsed laser in a vacuum of 10-3 Torr. The CR-39 specimens were exposed to LPP ions (flux: F=8.01×109-22.14×109 ions/m2, average energy: E av=52-297 keV) emitted along the normal to the metal surface in each case. Both F and E av were found to be a function of the room temperature Debye-Waller thermal parameter B and increase with increase in B-value. The structural behavior of virgin and implanted specimens was investigated using a ultra violet (UV)-visible spectrophotometer. The value of disorder content (Urbach energy E u) was found to lie in the range of 0.287-0.377 eV. The optical band gap energy (E g) for indirect transition decreased on implantation with metallic LPP ions, whereas such a variation in the case of direct transition was negligible. It was observed that E g for indirect transition increases with the increase in E u, whereas the dependence of E g for direct transition on E u was negligible.

  14. Cr-resistant rhizo- and endophytic bacteria associated with Prosopis juliflora and their potential as phytoremediation enhancing agents in metal-degraded soils

    Science.gov (United States)

    Khan, Muhammad U.; Sessitsch, Angela; Harris, Muhammad; Fatima, Kaneez; Imran, Asma; Arslan, Muhammad; Shabir, Ghulam; Khan, Qaiser M.; Afzal, Muhammad

    2015-01-01

    Prosopis juliflora is characterized by distinct and profuse growth even in nutritionally poor soil and environmentally stressed conditions and is believed to harbor some novel heavy metal-resistant bacteria in the rhizosphere and endosphere. This study was performed to isolate and characterize Cr-resistant bacteria from the rhizosphere and endosphere of P. juliflora growing on the tannery effluent contaminated soil. A total of 5 and 21 bacterial strains were isolated from the rhizosphere and endosphere, respectively, and were shown to tolerate Cr up to 3000 mg l−1. These isolates also exhibited tolerance to other toxic heavy metals such as, Cd, Cu, Pb, and Zn, and high concentration (174 g l−1) of NaCl. Moreover, most of the isolated bacterial strains showed one or more plant growth-promoting activities. The phylogenetic analysis of the 16S rRNA gene showed that the predominant species included Bacillus, Staphylococcus and Aerococcus. As far as we know, this is the first report analyzing rhizo- and endophytic bacterial communities associated with P. juliflora growing on the tannery effluent contaminated soil. The inoculation of three isolates to ryegrass (Lolium multiflorum L.) improved plant growth and heavy metal removal from the tannery effluent contaminated soil suggesting that these bacteria could enhance the establishment of the plant in contaminated soil and also improve the efficiency of phytoremediation of heavy metal-degraded soils. PMID:25610444

  15. Cr-resistant rhizo- and endophytic bacteria associated with Prosopis juliflora and their potential as phytoremediation enhancing agents in metal-degraded soils.

    Science.gov (United States)

    Khan, Muhammad U; Sessitsch, Angela; Harris, Muhammad; Fatima, Kaneez; Imran, Asma; Arslan, Muhammad; Shabir, Ghulam; Khan, Qaiser M; Afzal, Muhammad

    2014-01-01

    Prosopis juliflora is characterized by distinct and profuse growth even in nutritionally poor soil and environmentally stressed conditions and is believed to harbor some novel heavy metal-resistant bacteria in the rhizosphere and endosphere. This study was performed to isolate and characterize Cr-resistant bacteria from the rhizosphere and endosphere of P. juliflora growing on the tannery effluent contaminated soil. A total of 5 and 21 bacterial strains were isolated from the rhizosphere and endosphere, respectively, and were shown to tolerate Cr up to 3000 mg l(-1). These isolates also exhibited tolerance to other toxic heavy metals such as, Cd, Cu, Pb, and Zn, and high concentration (174 g l(-1)) of NaCl. Moreover, most of the isolated bacterial strains showed one or more plant growth-promoting activities. The phylogenetic analysis of the 16S rRNA gene showed that the predominant species included Bacillus, Staphylococcus and Aerococcus. As far as we know, this is the first report analyzing rhizo- and endophytic bacterial communities associated with P. juliflora growing on the tannery effluent contaminated soil. The inoculation of three isolates to ryegrass (Lolium multiflorum L.) improved plant growth and heavy metal removal from the tannery effluent contaminated soil suggesting that these bacteria could enhance the establishment of the plant in contaminated soil and also improve the efficiency of phytoremediation of heavy metal-degraded soils.

  16. Improved Cr II log(gf)s and Cr Abundances in the Photospheres of the Sun and Metal-Poor Star HD 84937

    Science.gov (United States)

    Lawler, James E.; Sneden, Chris; Nave, Gillian; Den Hartog, Elizabeth; Emrahoglu, Nuri; Cowan, John J.

    2017-01-01

    New laser induced fluorescence (LIF) data for eight levels of singly ionized chromium (Cr) and emission branching fraction (BF) measurements for 183 lines of the second spectrum of chromium (Cr II) are reported. A goal of this study is to reconcile Solar and stellar Cr abundance values based on Cr I and Cr II lines. Analyses of eighteen spectra from three Fourier Transform Spectrometers supplemented with ultraviolet spectra from a high resolution echelle spectrometer yield the BF measurements. Radiative lifetimes from LIF measurements are used to convert the BFs to absolute transition probabilities. These new laboratory data are applied to determine the Cr abundance log eps in the Sun and metal-poor star HD 84937. The mean result in the Sun is = 5.624 ± 0.009 compared to = 5.644 ± 0.006 on a scale with the H abundance log eps(H) = 12. Similarily the photosphere of HD 84937 is found to be in Saha balance with = 3.417 ± 0.006 and 0 eV) > = 3.374 ± 0.011 for this dwarf star. The resonance (E.P. = 0 eV) lines of Cr I reveal overionization of the ground level of neutral Cr. We find a correlation of Cr with the iron-peak element Ti, suggesting an associated or related nucleosynthetic production. Four iron-peak elements (Cr along with Ti, V and Sc) appear to have a similar (or correlated) production history - other iron-peak elements appear not to be associated with Cr.This work is supported in part by NASA grant NNX16AE96G (J.E.L.), by NSF grant AST-1516182 (J.E.L. & E.D.H.), by NASA interagency agreement NNH10AN381 (G.N.), and NSF grant AST-1211585 (C.S.). Postdoctoral research support for N. E. is from the Technological and Scientific Research Council of Turkey (TUBITAK).

  17. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Tanuwijaya, V. V., E-mail: viny.veronika@gmail.com [Engineering Physics, Faculty of Industrial Technology, Institut Teknologi Bandung Jalan Ganeca 10 Gd. T.P. Rachmat, Bandung 40132 (Indonesia); Hidayat, N. N., E-mail: avantgarde.vee@gmail.com; Agusta, M. K., E-mail: kemal@fti.itb.ac.id; Dipojono, H. K., E-mail: dipojono@tf.itb.ac.id

    2015-09-30

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO{sub 3} sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  18. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    Science.gov (United States)

    Tanuwijaya, V. V.; Hidayat, N. N.; Agusta, M. K.; Dipojono, H. K.

    2015-09-01

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO3 sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  19. Tensile properties and conductivities of a precipitation hardened and cold-rolled Cu-0.3Cr-0.1Zr alloy at cryogenic temperature

    Science.gov (United States)

    Umezawa, O.

    2015-12-01

    Cu-0.3Cr-0.1Zr alloy (in mass%) is one of typical precipitation hardened copper- based alloys, and exhibited an excellent combination of high strength and high conductivities at the temperature range of 4 K to 300 K. The tensile properties, electrical resistivity, thermal conductivity and magnetization of precipitation hardened and cold-rolled Cu-0.3Cr-0.1Zr alloy were measures in comparison with oxygen free copper at cryogenic temperatures. The Cu- 0.3Cr-0.1Zr showed higher yield ratio (yield strength / tensile strength) and lower the ratio of yield strength to electrical resistivity at cryogenic temperature than oxygen free copper. It exhibited high electrical and thermal conductivities, excellent non-magnetic stability and very low magnetic permeability at 4.2 K.

  20. Computation assisted design of favored composition for ternary Mg-Cu-Y metallic glass formation.

    Science.gov (United States)

    Wang, Q; Li, J H; Liu, B X

    2015-06-14

    With the aid of ab initio calculations, a realistic interatomic potential was constructed for the Mg-Cu-Y ternary system under the proposed formalism of smoothed and long-range second-moment approximation of tight-binding. Taking the potential as the starting base, an atomistic computation/simulation route was developed for designing favored and optimized compositions for Mg-Cu-Y metallic glass formation. Simulations revealed that the physical origin of metallic glass formation is the collapse of crystalline lattice when solute concentration exceeds a critical value, thus leading to predict a hexagonal region in the Mg-Cu-Y composition triangle, within which metallic glass formation is energetically favored. It is proposed that the hexagonal region can be defined as the intrinsic glass formation region, or quantitative glass formation ability of the system. Inside the hexagonal region, the driving force for formation of each specific glassy alloy was further calculated and correlated with its forming ability in practice. Calculations pinpointed the optimized stoichiometry in the Mg-Cu-Y system to be Mg64Cu16Y20, at which the formation driving force reaches its maximum, suggesting that metallic glasses designed to have compositions around Mg64Cu16Y20 are most stable or easiest to obtain. The predictions derived directly from the atomistic simulations are supported by experimental observations reported so far in the literature. Furthermore, Honeycutt-Anderson analysis indicated that pentagonal bipyramids (although not aggregating to form icosahedra) dominate in the local structure of the Mg-Cu-Y metallic glasses. A microscopic picture of the medium-range packing can then be described as an extended network of the pentagonal bipyramids, entangled with the fourfold and sixfold disclination lines, jointly fulfilling the space of the metallic glasses.

  1. Role of CrRLK1L Cell Wall Sensors HERCULES1 and 2, THESEUS1, and FERONIA in Growth Adaptation Triggered by Heavy Metals and Trace Elements

    Directory of Open Access Journals (Sweden)

    Julia Richter

    2017-09-01

    Full Text Available Cell walls are not only a protective barrier surrounding protoplasts but serve as signaling platform between the extracellular environment and the intracellular physiology. Ions of heavy metals and trace elements, summarized to metal ions, bind to cell wall components, trigger their modification and provoke growth responses. To examine if metal ions trigger cell wall sensing receptor like kinases (RLKs of the Catharanthus roseus RLK1-like (CrRLK1L family we employed a molecular genetic approach. Quantitative transcription analyses show that HERCULES1 (HERK1, THESEUS1 (THE1, and FERONIA (FER were differently regulated by cadmium (Cd, nickel (Ni, and lead (Pb. Growth responses were quantified for roots and etiolated hypocotyls of related mutants and overexpressors on Cd, copper (Cu, Ni, Pb, and zinc (Zn and revealed a complex pattern of gene specific, overlapping and antagonistic responses. Root growth was often inversely affected to hypocotyl elongation. For example, both HERK genes seem to negatively regulate hypocotyl elongation upon Cd, Ni, Zn, and Pb while they support root growth on Cd, Cu, and Ni. The different THE1 alleles exhibited a similar effect between roots and hypocotyls on Ni, where the loss-of-function mutant was more tolerant while the gain of function mutants were hypersensitive indicating that THE1 is mediating Ni specific inhibition of hypocotyl elongation in the dark. In contrast hypocotyl elongation of the knock-out mutant, fer-4, was hypersensitive to Ni but exhibited a higher tolerance to Cd, Cu, Pb, and Zn. These data indicate an antagonistic action between THE1 and FER in relation to hypocotyl elongation upon excess of Ni. FERs function as receptor for rapid alkalinization factors (RALFs was tested with the indicator bromocresol purple. While fer-4 roots strongly acidified control and metal ion containing media, the etiolated hypocotyls alkalized the media which is consistent with the already shorter hypocotyl of fer-4

  2. Development a Cu-based Metal Powder for Selective Laser Micro Sintering

    Energy Technology Data Exchange (ETDEWEB)

    Dai, C; Zhu, H H; Ke, L D; Lei, W J [Division of Laser Science and Technology, Wuhan National Laboratory for Optoelectronics, Institute of Optoelectronics Science and Engineering (China); Chen, B J, E-mail: chenbaijin@mail.hust.edu.cn [State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. of China (China)

    2011-02-01

    A Cu-based metal powder which consists of Cu and Cu-P alloy for selective micro laser sintering has been developed based on the theoretical analysis of the characteristics of the laser micro sintering metal powder. The characteristics of the wetting, capillary force and viscosity have been considered. The preliminary experimental investigation on the selective laser micro sintering Cu-based metal powder has been performed. A 50 W CW Nd:YAG laser was employed to sinter the developed metal powder mixture. The sintering mechanism and the effect of the process parameters on the characteristics of the sintering samples have been preliminary investigated. The results show that the mechanism of laser micro sintering this developed metal powder is liquid-phase sintering and Cu-P alloy powder plays an effectively binder in the sintering process. The process parameter has significant effects on the characteristics of the sintering parts. From the SEM image, two different microstructures of samples with different scan spacing parameters were compared and a better binding effect was obtained at a parameter of 0.05mm scan spacing.

  3. Prosopis juliflora--a green solution to decontaminate heavy metal (Cu and Cd) contaminated soils.

    Science.gov (United States)

    Senthilkumar, P; Prince, W S P M; Sivakumar, S; Subbhuraam, C V

    2005-09-01

    Soil and plant samples (root and shoot) of Prosopis juliflora were collected in the vicinity of metal based foundry units in Coimbatore and assessed for their heavy metal content (Cu and Cd) to ascertain the use of P. juliflora as a green solution to decontaminate soils contaminated with Cu and Cd. The results showed that Cu and Cd content was much higher in plant components compared to their extractable level in the soil. Furthermore, there exist a strong correlation between the distance of the sources of industrial units and accumulation of heavy metals in plants. Accumulation of Cd in roots is comparatively higher than that of shoots. However, in case of Cu no such clear trend is seen. Considering the accumulation efficiency and tolerance of P. juliflora to Cd and Cu, this plant can be explored further for the decontamination of metal polluted soils. On the other hand, in view of heavy metal accumulate the practice of providing foliage and pods as fodder for live stock should be avoided.

  4. Experimental Charge Density Study of Trichromium Linear Metal String Complex – Cr3(dpa)4Cl2

    DEFF Research Database (Denmark)

    Wu, Lai-Chin; Cheng, Ming-Chuan; Thomsen, Maja Krüger

    An experimental and theoretical charge density study, based on Bader’s Quantum Theory: Atoms in Molecule (QTAIM), on a trichromium metal string complex, Cr3(dpa)4Cl2(C2H5OC2H5)x(CH2Cl2)1-x (1, dpa- = bis(2-pyridyl)amido)) is performed. The structure and multipole model of 1 are performed by using...... experimental X-ray diffraction data which are collected at both 100 K using conventional X-ray source (DS1) and 15 K using synchrotron source (DS2). The three chromium metal string is bridged by four dpa- ligands. These tri-chromium metal ions are bonded to each other and terminated by two Cl- ions on the both...... ends, forming a [Cl(1)Cr(1)Cr(2)Cr(3)Cl(2)] linear string. Each Cr atoms are coordinated by four N atoms of each dpa- ligand. This metal string is slightly unsymmetrical at both data sets. The bond distance, from DS1 (DS2), of Cr(1)Cr(2), 2.3480(2) (2.3669(1)) Å, is 0.03 (0.003) Å shorter than Cr...

  5. Development of a CuNiCrAl Bond Coat for Thermal Barrier Coatings in Rocket Combustion Chambers

    Science.gov (United States)

    Fiedler, Torben; Rösler, Joachim; Bäker, Martin

    2015-12-01

    The lifetime of rocket combustion chambers can be increased by applying thermal barrier coatings. The standard coating systems usually used in gas turbines or aero engines will fail at the bond coat/substrate interface due to the chemical difference as well as the different thermal expansion between the copper liner and the applied NiCrAlY bond coat. A new bond coat alloy for rocket engine applications was designed previously with a chemical composition and coefficient of thermal expansion more similar to the copper substrate. Since a comparable material has not been applied by thermal spraying before, coating tests have to be carried out. In this work, the new Ni-30%Cu-6%Al-5%Cr bond coat alloy is applied via high velocity oxygen fuel spraying. In a first step, the influence of different coating parameters on, e.g., porosity, amount of unmolten particles, and coating roughness is investigated and a suitable parameter set for further studies is chosen. In a second step, copper substrates are coated with the chosen parameters to test the feasibility of the process. The high-temperature behavior and adhesion is tested with laser cycling experiments. The new coatings showed good adhesion even at temperatures beyond the maximum test temperatures of the NiCrAlY bond coat in previous studies.

  6. Interfacial reactions and compound formation of Sn-Ag-Cu solders by mechanical alloying on electroless Ni-P/Cu under bump metallization

    Science.gov (United States)

    Kao, Szu-Tsung; Duh, Jenq-Gong

    2005-08-01

    Electroless Ni-P under bump metallization (UBM) has been widely used in electronic interconnections due to the good diffusion barrier between Cu and solder. In this study, the mechanical alloying (MA) process was applied to produce the SnAgCu lead-free solder pastes. Solder joints after annealing at 240°C for 15 min were employed to investigate the evolution of interfacial reaction between electroless Ni-P/Cu UBM and SnAgCu solder with various Cu concentrations ranging from 0.2 to 1.0 wt.%. After detailed quantitative analysis with an electron probe microanalyzer, the effect of Cu content on the formation of intermetallic compounds (IMCs) at SnAgCu solder/electroless Ni-P interface was evaluated. When the Cu concentration in the solder was 0.2 wt.%, only one (Ni, Cu)3Sn4 layer was observed at the solder/electroless Ni-P interface. As the Cu content increased to 0.5 wt.%, (Cu, Ni)6Sn5 formed along with (Ni, Cu)3Sn4. However, only one (Cu, Ni)6Sn5 layer was revealed, if the Cu content was up to 1 wt.%. With the aid of microstructure evolution, quantitative analysis, and elemental distribution by x-ray color mapping, the presence of the Ni-Sn-P phase and P-rich layer was evidenced.

  7. Improvement of microstructure and property of cold-sprayed Cu-4 at.%Cr-2 at.%Nb alloy by heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.-Y. [LERMPS, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort Cedex (France)]. E-mail: wenyali_cn@hotmail.com; Guo, X.P. [LERMPS, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort Cedex (France); Verdy, C. [LERMPS, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort Cedex (France); Dembinski, L. [LERMPS, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort Cedex (France); Liao, H.L. [LERMPS, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort Cedex (France); Coddet, C. [LERMPS, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort Cedex (France)

    2006-08-15

    The effect of vacuum heat treatment on the microstructure and microhardness of the cold-sprayed Cu-4 at.%Cr-2 at.%Nb alloy was investigated. After heat treatment, a Cr{sub 2}Nb phase formed in the gas-atomized powder was uniformly distributed in the matrix. Minimal grain growth of the Cr{sub 2}Nb phase was observed accompanying the healing-up of the incomplete interfaces between the deposited particles at the elevated treatment temperatures. The microstructure and microhardness of the annealed cold-sprayed Cu-4 at.%Cr-2 at.%Nb alloy were comparable with those of the deposits fabricated by vacuum plasma spraying, which makes it a promising material for regeneratively cooled rocket engine applications.

  8. 微电解-生物膜复合工艺净化含重金属离子的有机废水%Purification of Organic Wastewater Containing Cu2+ and Cr3+ by a Combined Process of Micro Electrolysis and Biofilm

    Institute of Scientific and Technical Information of China (English)

    李天成; 姜斌; 冯霞; 王大为; 袁绍军; 李鑫钢

    2003-01-01

    A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastewaters containing heavy metal ions such as Cu2+ and Cr3+, and the relevant purifying mechanism was also addressed. In detail, organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes. However, for heavy metal ions (Cu2+, Cr3+), part was removed by electrodeposition, and some was adsorbed on biofilm. In order to compare with the combined process of micro electrolysis and biofilm, the experimental data of micro electrolysis process (intermittent) or biofilm process (continuous) were provided, and the kinetic data of C6H12O6 (glucose) biodegradation by cultured microbes or acclimated microbes were also obtained. These experimental results indicated that for wastewater initially consisted of C6H12O6 (500mg. L-1), Cu2+ and Cr3+ (10mg. L-1), after treatment, its concentrations of C6H12O6, Cu2+ and Cr3+ were lowered to the level of 55-65 mg.L-1, and less than 1 mg.L-1, respectively. And the industrial reused water standards could be met by treated wastewater.

  9. Metal-organic Kagome lattices M3(2,3,6,7,10,11-hexaiminotriphenylene)2 (M = Ni and Cu): from semiconducting to metallic by metal substitution.

    Science.gov (United States)

    Chen, Shuang; Dai, Jun; Zeng, Xiao Cheng

    2015-02-28

    Motivated by recent experimental synthesis of a semiconducting metal-organic graphene analogue (J. Am. Chem. Soc., 2014, 136, 8859), i.e., Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2 [Ni3(HITP)2], a new Kagome lattice, Cu3(HITP)2, is designed by substituting the coordination of Ni by Cu. Such substitution results in interesting changes in electronic properties of the M3(HITP)2 bulk and two-dimensional (2D) sheets. In Ni3(HITP)2, each Ni atom adopts the dsp(2) hybridization, forming a perfect 2D conjugation, whereas in Cu3(HITP)2, each Cu atom adopts the sp(3) hybridization, resulting in a distorted 2D sheet. The M3(HITP)2 bulks, assembled from M3(HITP)2 sheets via both strong π-π interaction and weak metal-metal interaction, are metallic. However, the 2D Ni3(HITP)2 sheet is a semiconductor with a narrow band gap whereas the 2D Cu3(HITP)2 sheet is a metal. Remarkably, both the 2D M3(HITP)2 Kagome lattices possess Dirac bands in the vicinity of the Fermi level. Additional ab initio molecular dynamics simulations show that both sheets exhibit high thermal stability at elevated temperatures. Our theoretical study offers new insights into tunability of electronic properties for the 2D metal-organic frameworks (MOFs).

  10. Microstructure and properties of Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys prepared by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xing-Wu, E-mail: fallenrain922@163.com [Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China); Liu, Chun-Ge [Department of Transportation and Municipal Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China)

    2013-03-15

    Highlights: ► We use a new method (laser cladding) to prepare Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys. ► We studied the effect of Ni content on alloys’ properties. ► Alloys show high microhardness, excellent corrosion resistance and wear resistance. ► The laser cladding layers play a good protective effect on Q235 steel. -- Abstract: The Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys were prepared by laser cladding. Using metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation and tribometer the structure and hardness, corrosion resistance and wear resistance of Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys were tested. The result shows that, Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloy samples consist of the cladding zone, bounding zone and heat affected zone. The bounding zone is between cladding layer and the substrate of a good combination; the cladding zone is composed mainly of axis crystal, nanocrystalline and fine white crystals. The Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys coating phase structure samples (FCC and BCC structure) due to high-entropy effect. The surface microhardness of Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys samples up to 1102 HV, about 4 times as the substrate, and the hardness increases with increasing Ni content. Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys coating has good corrosion resistance in 1 mol/L NaOH solution and 3.5% NaCl solution. With the increase of Ni content, the corrosion resistance first increases and then decreases. The relative wear resistance of Al{sub 2}CrFeCoCuTiNi{sub x} high-entropy alloys coating shows a first increased and then a decreased trend with the increase of Ni content. Both the hardness and ductility are affected by wear resistance. The coating can play a good protective role on substrate Q235 steel.

  11. Study on Two-phase Nanocrystalline Nd8.5Fe74Co5Cu1NblZr3Cr1B6.5 Permanent Magnet

    Institute of Scientific and Technical Information of China (English)

    Jiansen NI; Hui XU; Mingyuan ZHU; Qiang LI; Bangxin ZHOU; Yuanda DONG

    2004-01-01

    Nd8.5Fe74Co5Cu1Nb1Zr3Cr1B6.5 bonded magnets were prepared by melt-spun and subsequent heat treatment. Magnetic properties of Br=0.68 T, JHc=716 Ka/m, (BH)max=77 Kj/m3 were achieved. The addition of Cr element shows to be significantly advantageous in reducing grain size and increasing the intrinsic coercivity.

  12. Monitoring heavy metal Cr in soil based on hyperspectral data using regression analysis

    Science.gov (United States)

    Zhang, Ningyu; Xu, Fuyun; Zhuang, Shidong; He, Changwei

    2016-10-01

    Heavy metal pollution in soils is one of the most critical problems in the global ecology and environment safety nowadays. Hyperspectral remote sensing and its application is capable of high speed, low cost, less risk and less damage, and provides a good method for detecting heavy metals in soil. This paper proposed a new idea of applying regression analysis of stepwise multiple regression between the spectral data and monitoring the amount of heavy metal Cr by sample points in soil for environmental protection. In the measurement, a FieldSpec HandHeld spectroradiometer is used to collect reflectance spectra of sample points over the wavelength range of 325-1075 nm. Then the spectral data measured by the spectroradiometer is preprocessed to reduced the influence of the external factors, and the preprocessed methods include first-order differential equation, second-order differential equation and continuum removal method. The algorithms of stepwise multiple regression are established accordingly, and the accuracy of each equation is tested. The results showed that the accuracy of first-order differential equation works best, which makes it feasible to predict the content of heavy metal Cr by using stepwise multiple regression.

  13. Chemistry and electronic properties of ferromagnetic metal-organic semiconductor interfaces: Fe on CuPc

    Energy Technology Data Exchange (ETDEWEB)

    Aristov, V.Yu. [IFW Dresden, 01069 Dresden (Germany); Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow distr., 142432 (Russian Federation); Molodtsova, O.V.; Knupfer, M. [IFW Dresden, 01069 Dresden (Germany); Ossipyan, Yu.A. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow distr., 142432 (Russian Federation); Doyle, B.P. [TASC-INFM Laboratory, Area Science Park - Basovizza, 34012 Trieste (Italy); Department of Physics, University of Johannesburg, PO Box 524, Auckland Park, 2006 (South Africa); Nannarone, S. [TASC-INFM Laboratory, Area Science Park - Basovizza, 34012 Trieste (Italy); Dipartimento di Ingegneria dei Materiali ed Amb., Universita di Modena e Reggio Emilia (Italy)

    2009-12-15

    The chemistry and electronic properties of the interfaces formed between the ferromagnetic metal (Fe) and the model organic semiconductor copper phthalocyanine are investigated in ultra-high vacuum conditions for the case of metal deposition onto the organic molecular thin film. The studies were performed by means of core-level and valence-band high-resolution photoemission electron spectroscopy (PES) as well as near-edge X-ray absorption fine structure using synchrotron radiation. Metal overlayer formation on the top of the organic semiconductor was observed without substantial penetration of deposited metal species into the organic film. At the thin interface layer the ferromagnetic metal shows strong chemical interaction with the nitrogen and carbon of the organic films. Moreover, our results infer that, as a consequence of Fe deposition onto CuPc, central copper atoms of the organic molecules at the interface are reduced from Cu(II) to Cu(I), while Fe atoms are oxidized and/or the ferromagnetic metal replaces this central Cu atom. Further optimization of such an interface is thus required to allow and/or facilitate the injection of spin-polarized carriers into organic semiconductors. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  14. Applications of Cr-Based Metal Nitride Hard Coatings Using Multi-Magnetron Sputtering Sources and Elemental Metal Targets

    Institute of Scientific and Technical Information of China (English)

    Shicai Yang; Eric Wiemann; D.G. Teer

    2004-01-01

    Cr-based nitride hard coatings were produced by multi-magnetron sputtering sources using elemental metal materials. Cr, Ti, Mo, V, Al, and Y target materials were used for the metal sources whilst nitrogen was introduced at the same time to produce multilayer nitride hard coatings. The deposition process was optimised according to the properties of hardness, adherence and wear measured using microhardness, scratch, Rockwell indentation and pin-on-disc tests. The coatings were deposited onto hard metal carbide as well as high speed steel cutting tools such as inserts and drills. The coated inserts were tested on a wide range of difficult to machine materials using a Boehringer VDF180-C CNC lathe. The machining was performed under interrupted cutting conditions and the results were compared with those obtained using an advanced commercially available TiA1N coating. The coated carbide drills were tested under dry conditions to cut hard alloy steel and the coated tool steel drills were tested under lubricant conditions to cut carbon steel with comparing the similar tests on commercial TiN coatings. These test results were compared with those from drills coated with a commercial TiN.

  15. Applications of Cr-Based Metal Nitride Hard Coatings Using Multi-Magnetron Sputtering Sources and Elemental Metal Targets

    Institute of Scientific and Technical Information of China (English)

    ShicaiYang; EricWiemann; D.C.Teer

    2004-01-01

    Cr-based nitride hard coatings were produced by multi-magnetron sputtering sources using elemental metal materials. Cr, Ti, Mo, V, A1, and Y target materials were used for the metal sources whilst nitrogen was introduced at the same time to produce multilayer nitride hard coatings. The deposition process was optimised according to the properties of hardness, adherence and wear measured using microhardness, scratch, Rockwell indentation and pin-on-disc tests. The coatings were deposited onto hard metal carbide as well as high speed steel cutting tools such as inserts and drills. The coated inserts were tested on a wide range of difficult to machine materials using a Boehringer VDF180-C CNC lathe. The machining was performed under interrupted cutting conditions and the results were compared with those obtained using an advanced commercially available TiA1N coating. The coated carbide drills were tested under dry conditions to cut hard alloy steel and the coated tool steel drills were tested under lubricant conditions to cut carbon steel with comparing the similar tests on commercial TiN coatings. These test results were compared with those from drills coated with a commercial TiN.

  16. Comparison between B CR sequential extraction and geo-accumulation method to evaluate metal mobility in sediments of Dongting Lake, Central China

    Institute of Scientific and Technical Information of China (English)

    YAO Zhigang

    2008-01-01

    The form in which a metal exists strongly influences its mobility and thus,the effects on the environment.Operational methods of speciation analysis,such as the use of sequential extraction procedures,are commonly applied.The Dongting Lake,the second largest fresh-water lake in China,contains three China wetlands of international importance,the East Dongting Lake,South Dongting Lake,and West Dongting Lake.In this work,an optimized BCR sequential extraction procedure was used to assess the environmental risk of Cd,Cr,Cu,Ni,Pb and Zn in contaminated sediment of the Dongting Lake.The procedure was evaluated by using a certified reference material,BCR701.The results of the partitioning study indicated that in the lake sediments,more easily mobilized forms(acid exchangeable) were predominant for Cd,particularly in the samples from the East Dongting Lake.In contrast,the largest amount of Pb was associated with the iron and manganese oxide fractions and Cu,Zn,Cr,and Ni analyzed were mainly distributed in residual phase at an average percentage greater than 60% of the total metals.The potential risk to the lake's water contamination was highest in the East Dongting Lake based on the calculated contamination factors.On the other hand,the total metal content was determined as well by inductively coupled plasma and mass spectrometry(ICP-MS)and assessed by using geo-accumulation index.The assessment results using geo-accumulation index were compared with the information on metal speciation.Both were correspondent with each other.

  17. Elucidating the mechanism of Cr(VI) formation upon the interaction with metal oxides during coal oxy-fuel combustion.

    Science.gov (United States)

    Chen, Juan; Jiao, Facun; Zhang, Lian; Yao, Hong; Ninomiya, Yoshihiko

    2013-10-15

    The thermodynamics underpinning the interaction of Cr-bearing species with basic metal oxides, i.e. K2O, Fe2O3, MgO and CaO, during the air and oxy-fuel combustion of coal have been examined. The synchrotron-based X-ray adsorption near-edge spectroscopy (XANES) was used for Cr speciation. For the oxides tested, Cr(VI) formation is dominated by the reduction potential of the metals. The oxides of Ca(2+) with high reduction potential favored the oxidation of Cr(III), same for K(+). The other two basic metals, Fe2O3 and MgO with lower reduction potentials reacted with Cr(III) to form the corresponding chromites at the temperatures above 600°C. Coal combustion experiments in drop-tube furnace have confirmed the rapid capture of Cr vapors, either trivalent or hexavalent, by CaO into solid ash. The existence of HCl in flue gas favored the vaporization of Cr as CrO2Cl2, which was in turn captured by CaO into chromate. Both Fe2O3 and MgO exhibited less capability on scavenging the Cr(VI) vapor. Particularly, MgO alone exhibited a low capability for capturing the vaporized Cr(III) vapors. However, its co-existence with CaO in the furnace inhibited the Cr(VI) formation. This is beneficial for minimizing the toxicity of Cr in the coal combustion-derived fly ash.

  18. A porous Cu(II) metal-organic framework: Synthesis, crystal structure and gas adsorption properties

    Science.gov (United States)

    Li, Wu-Wu; Guo, Ying; Zhang, Wei-Hong

    2017-09-01

    Presented here is a new porous Cu(II) metal-organic framework, namely [Cu(tdc)(H2O)]n·n(DMA) (1 H2tdc = thiophene-2,5-dicarboxylic acid, DMA = N,N‧-dimethylacetamide), which was obtained by the self-assembly reaction of CuCl2 and H2tdc under solvothermal conditions. Single crystal X-ray diffraction analysis revealed that compound 1 features a 3D porous framework based on 1D chain structure subunits, and the 1D rhombohedral channels are occupied by the lattice DMA molecules. Gas adsorption studies reveal that this desolvated sample exhibit high uptake capacity for light hydrocarbons.

  19. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    Energy Technology Data Exchange (ETDEWEB)

    Gargarella, P., E-mail: piter@ufscar.br [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rodovia Washington Luiz, Km 235, 13565-905 São Carlos, São Paulo (Brazil); Pauly, S.; Stoica, M.; Kühn, U. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Vaughan, G. [European Synchrotron Radiation Facilities, BP 220, 38043 Grenoble (France); Afonso, C. R. M. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rodovia Washington Luiz, Km 235, 13565-905 São Carlos, São Paulo (Brazil); Eckert, J. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Institut für Werkstoffwissenschaft, Technische Universität Dresden, D-01062 Dresden (Germany)

    2015-01-01

    The structural evolution of Ti{sub 50}Cu{sub 43}Ni{sub 7} and Ti{sub 55}Cu{sub 35}Ni{sub 10} metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  20. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    Science.gov (United States)

    Gargarella, P.; Pauly, S.; Stoica, M.; Vaughan, G.; M. Afonso, C. R.; Kühn, U.; Eckert, J.

    2015-01-01

    The structural evolution of Ti50Cu43Ni7 and Ti55Cu35Ni10 metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  1. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    Directory of Open Access Journals (Sweden)

    P. Gargarella

    2015-01-01

    Full Text Available The structural evolution of Ti50Cu43Ni7 and Ti55Cu35Ni10 metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  2. Immobilisation of Cu, Pb and Zn in Scrap Metal Yard Soil Using Selected Waste Materials.

    Science.gov (United States)

    Kamari, A; Putra, W P; Yusoff, S N M; Ishak, C F; Hashim, N; Mohamed, A; Isa, I M; Bakar, S A

    2015-12-01

    Immobilisation of heavy metals in a 30-year old active scrap metal yard soil using three waste materials, namely coconut tree sawdust (CTS), sugarcane bagasse (SB) and eggshell (ES) was investigated. The contaminated soil was amended with amendments at application rates of 0 %, 1 % and 3 % (w/w). The effects of amendments on metal accumulation in water spinach (Ipomoea aquatica) and soil metal bioavailability were studied in a pot experiment. All amendments increased biomass yield and reduced metal accumulation in the plant shoots. The bioconcentration factor and translocation factor values of the metals were in the order of Zn > Cu > Pb. The addition of ES, an alternative source of calcium carbonate (CaCO3), has significantly increased soil pH and resulted in marked reduction in soil metal bioavailability. Therefore, CTS, SB and ES are promising low-cost immobilising agents to restore metal contaminated land.

  3. Microstructural evolution during direct laser sintering of multi-component Cu-based metal powder

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi-fu; GU Dong-dong; WU Peng; YANG Jia-lin; WANG Yang

    2005-01-01

    A multi-component Cu-based metal powder was chosen for direct laser sintering. The powder consists of a mixture of high-purity Cu powder, pre-alloyed CuSn and CuP powder. Liquid phase sintering with complete melting of the binder (CuSn) but non-melting of the cores of structural metal (Cu) proves to be a feasible mechanism for laser sintering of this powder system. The microstructural evolution of the sintered powder with variation of laser processing parameters was presented. High sintering activities and sound densification response were obtained by optimizing the laser powers and scan speeds. Using a high laser power accompanied by a high scan speed gives rise to balling effect. At a high laser power with a slow scan speed the sintering mechanism may change into complete melting/solidification, which decreases the obtainable sintered density. The role of additive phosphorus in the laser sintering process is addressed. Phosphorus can act as a fluxing agent and has a preferential reaction with oxygen to form phosphatic slag, protecting the Cu particles from oxidation. The phosphatic slag shows a concentration along grain boundaries due to its light mass as well as the short thermal cycle of SLS.

  4. Cooling rate dependence of simulated Cu64.5Zr35.5 metallic glass structure

    Science.gov (United States)

    Ryltsev, R. E.; Klumov, B. A.; Chtchelkatchev, N. M.; Shunyaev, K. Yu.

    2016-07-01

    Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu64.5Zr35.5 alloy during the cooling in a wide range of cooling rates γ ∈ (1.5 ṡ 109, 1013) K/s. Investigating short- and medium-range orders, we show that the structure of Cu64.5Zr35.5 metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to an increase of abundances of both the icosahedral-like clusters and Frank-Kasper Z16 polyhedra. The amounts of these clusters in the glassy state drastically increase at the γmin = 1.5 ṡ 109 K/s. Analysing the structure of the glass at γmin, we observe the formation of nano-sized crystalline grain of Cu2Zr intermetallic compound with the structure of Cu2Mg Laves phase. The structure of this compound is isomorphous with that for Cu5Zr intermetallic compound. Both crystal lattices consist of two types of clusters: Cu-centered 13-atom icosahedral-like cluster and Zr-centered 17-atom Frank-Kasper polyhedron Z16. That suggests the same structural motifs for the metallic glass and intermetallic compounds of Cu-Zr system and explains the drastic increase of the abundances of these clusters observed at γmin.

  5. One-Step Catalytic Synthesis of CuO/Cu2O in a Graphitized Porous C Matrix Derived from the Cu-Based Metal-Organic Framework for Li- and Na-Ion Batteries.

    Science.gov (United States)

    Kim, A-Young; Kim, Min Kyu; Cho, Keumnam; Woo, Jae-Young; Lee, Yongho; Han, Sung-Hwan; Byun, Dongjin; Choi, Wonchang; Lee, Joong Kee

    2016-08-03

    The hybrid composite electrode comprising CuO and Cu2O micronanoparticles in a highly graphitized porous C matrix (CuO/Cu2O-GPC) has a rational design and is a favorable approach to increasing the rate capability and reversible capacity of metal oxide negative materials for Li- and Na-ion batteries. CuO/Cu2O-GPC is synthesized through a Cu-based metal-organic framework via a one-step thermal transformation process. The electrochemical performances of the CuO/Cu2O-GPC negative electrode in Li- and Na-ion batteries are systematically studied and exhibit excellent capacities of 887.3 mAh g(-1) at 60 mA g(-1) after 200 cycles in a Li-ion battery and 302.9 mAh g(-1) at 50 mA g(-1) after 200 cycles in a Na-ion battery. The high electrochemical stability was obtained via the rational strategy, mainly owing to the synergy effect of the CuO and Cu2O micronanoparticles and highly graphitized porous C formed by catalytic graphitization of Cu nanoparticles. Owing to the simple one-step thermal transformation process and resulting high electrochemical performance, CuO/Cu2O-GPC is one of the prospective negative active materials for rechargeable Li- and Na-ion batteries.

  6. Manufacture of thick VPS W coatings on relatively large CuZrCr substrate and its steady high heat load performance

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chunming, E-mail: denghans@126.com; Liu, Min; Yang, Zhenxiao; Deng, Changguang; Zhou, Kesong; Kuang, Ziqi; Zhang, Jifu

    2014-12-15

    W material is considered as one of potential Plasma Facing Materials (PFMs) for its high melting point, excellent stability at elevated temperature, good thermal conductivity, excellent anti-plasma sputtering and low Tritium retention. Functionally graded W/Cu coating was applied on CuCrZr substrate (250 mm × 120 mm × 30 mm) with compositionally gradient W/Cu as bond coat (0.4–0.6 mm) and 1.5 mm thick W coating as top coat via Vacuum Plasma Spraying (VPS) for continuous deposition of 5 h. Microstructure, chemical composition, porosity and adhesive strength for as sprayed thick W coating on the CuCrZr substrate were characterized by means of SEM, ICP-MS, Mercury Intrusion Porosimeter and tensile strength tester. The steady high heat load (HHL) performance for W/Cu functional gradient coating was evaluated by high energy electron beam. The results showed that thick VPS W coated CuCrZr substrate can withstand the steady high heat load at the electron beam power density of 9 MW/m{sup 2} for 1000 cycles.

  7. Structural study of CuZr and Cu50Zr45Al5 metallic glasses in relation to their GFA and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Kaban, Ivan; Escher, Benjamin; Eckert, Juergen [TU Dresden, Institute of Materials Science (Germany); IFW Dresden, Institute for Complex Materials (Germany); Jovari, Pal [Institute for Solid State Physics and Optics, Budapest (Hungary); Webb, Adam; Regier, Tom [Canadian Light Source, Saskatoon (Canada); Beuneu, Brigitte [Laboratoire Leon Brillouin, CEA-Saclay (France); Kokotin, Valentin [ThyssenKrupp Steel Europe AG, Duisburg (Germany); Mattern, Norbert [IFW Dresden, Institute for Complex Materials (Germany)

    2014-07-01

    In this work we investigate the atomic structure of CuZr and Cu50Zr45Al5 metallic glasses in view of their glass-forming ability and mechanical properties. Using a combination of the state-of-the-art experimental techniques (synchrotron X-ray diffraction and absorption spectroscopy and neutron diffraction), reverse Monte-Carlo simulation and Molecular Dynamics modelling we have obtained partial pair distribution functions, coordination numbers and bond lengths for the glasses studied. Remarkable differences are found for the total as well as for the partial pair distributions in the CuZr and Cu50Zr45Al5 metallic glasses, especially for the Cu-Cu and Zr-Zr pairs at the second and higher coordination shells, suggesting important role of the medium-range order in the glass formation and in the mechanical behaviour.

  8. Progresses in Electroplating Zn, Cu, Ni,Cr and its Alloys%电镀Zn、Cu、Ni、Cr及其合金的研究进展

    Institute of Scientific and Technical Information of China (English)

    安茂忠; 屠振密

    2001-01-01

    论述了电镀单金属锌、铜、镍、铬及其合金的主要特性、应用和研究进展。 电镀 锌的研究重点是开发低毒、高效的复合添加剂,电镀锌基合金得到广泛应用。电镀铜及铜合 金的研究重点是添加剂作用机理和电镀新技术的开发。电镀镍及镍合金的研究重点是采用新 工艺技术改善镀层性能及电沉积机理的探讨。电镀铬的发展是研制复合促进剂改善六价铬镀 液的性能、研制低毒的三价铬镀液以及代铬合金镀层的开发。%Discuss the important characteristics of zinc, copper,nickel,chromium and its alloys,and also have a discussion on the application and development of these co ating.The focus of the research in electroplated Zn is to develop a compound ad ditive agent with low poison and high effect.The use of the electroplated zinc-i ron group metals alloy is very comprehensive.The emphasis of research in electro plated Cu and its alloy is the mechanism of additive agent and to develop a new technology.The emphasis of research in electroplated Ni and its alloy is to use a new technology to improve the capability of coating and to probe the mechanism of electrodeposition.The development of electroplated Cr is to invent a new add itive agent to improve the performance of electrolyte contained Cr6+ and a new low poisonous electrolyte contained Cr3+,invent a new alloy coating t o substitute the Cr coating.

  9. Molecular dynamics simulations of the structure evolutions of Cu-Zr metallic glasses under irradiation

    Science.gov (United States)

    Lang, Lin; Tian, Zean; Xiao, Shifang; Deng, Huiqiu; Ao, Bingyun; Chen, Piheng; Hu, Wangyu

    2017-02-01

    Molecular dynamics simulations have been performed to investigate the structural evolution of Cu64.5Zr35.5 metallic glasses under irradiation. The largest standard cluster analysis (LSCA) method was used to quantify the microstructure within the collision cascade regions. It is found that the majority of clusters within the collision cascade regions are full and defective icosahedrons. Not only the smaller structures (common neighbor subcluster) but also primary clusters greatly changed during the collision cascades; while most of these radiation damages self-recover quickly in the following quench states. These findings indicate the Cu-Zr metallic glasses have excellent irradiation-resistance properties.

  10. HEAVY METALS (Ni, Cu, Zn AND Cd CONTENT IN SERUM OF RAT FED GREEN MUSSELS

    Directory of Open Access Journals (Sweden)

    Muhammad Yudhistira Azis

    2015-11-01

    Full Text Available Green mussel (Perna viridis can playing role as bio-indicator or biomonitoring agent for heavy-metalcontaminations in the sea. In this research, the concentrations of four elements Ni, Cu, Zn and Cd in P. viridis and in the serum of rat which orally feed by P. viridis were determined by Atomic Absorption Spectrometry (AAS following dry acid digestion. Parameter analysis was evaluated by determining confidence limit for the obtained results. The result showed that there was a sequence of heavy-metal content in green mussels sample and laboratory rats serum, such as Ni < Cd < Cu < Zn. Keywords: heavy metals, green mussels, laboratory rats serum, AAS

  11. Precipitation of metallic chromium during rapid cooling of Cr2O3 slags

    Directory of Open Access Journals (Sweden)

    J. Burja

    2017-01-01

    Full Text Available The slag systems of CaO-SiO2- Cr2O3 and Al2O3-CaO-MgO-SiO2- Cr2O3 were analyzed. These slag systems occur in the production of stainless steel and are important from the process metallurgy point of view. Synthetic slag samples with different chromium oxide content were prepared and melted. The melted slag samples where then rapidly cooled on large steel plates, so that the high temperature microstructure was preserved. The samples were analyzed by scanning electron microscopy (SEM and X-ray diffraction (XRD. The precipitation of different chromium oxide phases was studied, but most importantly the precipitation of metallic chromium was observed. These findings help us interpret industrial slag samples.

  12. Influence of phosphorus element on direct laser sintering of multicomponent Cu-based metal powder

    Science.gov (United States)

    Gu, D. D.; Shen, Y. F.

    2006-12-01

    This article presents a detailed investigation on the influence of the phosphorus element upon the laser sintering of a multicomponent Cu-based metal powder system consisting of Cu, Cu-10Sn, and Cu-8.4P. Powder systems containing 0, 10, 15, and 20 wt pct CuP were sintered in atmosphere at room temperature using the following optimal processing parameters: laser power of 350 W, scan speed of 0.04 m/s, scan line spacing of 0.15 mm, and layer thickness of 0.25 mm. It was found that the relative density of the sintered sample with 15 wt pct CuP increased by 24,4 pct as compared with the sample without phosphorus addition. A further increase in the CuP content (≥20 wt pct), however, resulted in a poor densification with a serious delamination. The exact metallurgical roles of the phosphorus element in the laser sintering process were addressed as follows. First, the phosphorus could prevent the sintering system from oxidation by forming CuPO3, thereby improving the wetting characteristics and the sintering kinetics. Second, the phosphorus could decrease the surface tension of molten materials, leading to a successive transition from highly discontinuous sintered tracks to fairly coherent ones with increasing the phosphorus content. Third, the phosphorus could lower the melt viscosity, thereby improving the microstructural homogeneity of the laser-sintered samples.

  13. Metal-organic framework: Structure and magnetic properties of [Cu3(BTC)2 (L)x·(CuO)y]n (L=H2O, DMF)

    Science.gov (United States)

    da Silva, Gilvaldo G.; Machado, F. L. A.; Junior, S. Alves; Padrón-Hernández, E.

    2017-09-01

    The compounds [Cu3(BTC)2(L)x·(CuO)y], with BTC (benzene 1,3,5-tricarboxylate) and L (H2O or DMF) were prepared using electrochemical synthesis. Structural and morphologic characterizations were performed by X-ray diffraction and scanning electronic microscopy. The [Cu3(BTC)2 (L)x·(CuO)y] contain dimeric [Cu2(O2CR)]4 units with three possible spin configurations arising from Cu(II) 3d9 states and Cu-Cu δ bond. We observed an unusual very strong antiferromagnetic coupling in temperatures ranging from 100 K to 350 K for [Cu3(BTC)2.(H2O)3. (CuO)y]n. The inverse susceptibility versus temperature shows a linearity from 20 K up to 65 K fitting the Curie-Weiss law, for L = DMF. The CW X-band electron paramagnetic resonance spectroscopy (EPR) was important to explore the coordination state for DMF in the network. It was observed that DMF is located in an equatorial geometry of the coordination network experimenting interactions from the nitrogen and copper ions.

  14. Metal-organic framework derived porous CuO/Cu2O composite hollow octahedrons as high performance anode materials for sodium ion batteries.

    Science.gov (United States)

    Zhang, Xiaojie; Qin, Wei; Li, Dongsheng; Yan, Dong; Hu, Bingwen; Sun, Zhuo; Pan, Likun

    2015-11-25

    Porous CuO/Cu2O composite hollow octahedrons were synthesized simply by annealing Cu-based metal-organic framework templates. When evaluated as anode materials for sodium ion batteries, they exhibit a high maximum reversible capacity of 415 mA h g(-1) after 50 cycles at 50 mA g(-1) with excellent cycling stability and good rate capability.

  15. Spin glass state and its correlations with the magnetic and electrical properties as well as with the defectiveness in the spinels CuCr{sub 2}X{sub 4} (X = S, Se) doped with Sb

    Energy Technology Data Exchange (ETDEWEB)

    Krok-Kowalski, J. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40007 Katowice (Poland)]. E-mail: warcz@us.edu.pl; Warczewski, J. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40007 Katowice (Poland); Krajewski, K. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40007 Katowice (Poland); Duda, H. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40007 Katowice (Poland); Gusin, P. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40007 Katowice (Poland); Sliwinska, T. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40007 Katowice (Poland); Pacyna, A. [Institute of Nuclear Physics, ul. Radzikowskiego 152, 31342 Krakow (Poland); Mydlarz, T. [International Laboratory of High Magnetic Fields and Low Temperatures, ul. Gajowicka 95, 53529 Wroclaw (Poland); Matyjasik, S. [International Laboratory of High Magnetic Fields and Low Temperatures, ul. Gajowicka 95, 53529 Wroclaw (Poland); Malicka, E. [University of Silesia, Institute of Chemistry, ul. Szkolna 9, 40006 Katowice (Poland); Kita, A. [University of Silesia, Institute of Chemistry, ul. Szkolna 9, 40006 Katowice (Poland)

    2007-03-14

    High degree of defectiveness both in the stoichiometric CuCr{sub 2-x}Sb {sub x}S{sub 4} (x = 0.3, 0.4, 0.5) and nonstoichiometric Cu{sub 1+x}Cr{sub 1.5+y}Sb{sub 0.5+z}Se{sub 4+t} (where: -0.02 {<=} x {<=} 0.01, 0.03 {<=} y {<=} 0.35, -0.2 {<=} z {<=} -0.02, 0.01 {<=} t {<=} 0.08) spinels doped with Sb has been determined with the aid of the vacancy model. From the analysis carried out of the effective magnetic moments and the exchange integrals, it follows that in the spinels with sulphur mainly the cation subarrays are defected whereas in the spinels with selenium the defectiveness appears mainly in the anion subarrays. It turned out that in the spinels with sulphur the ferromagnetic cluster spin glass states appear accompanied by the large negative magnetoresistance, whereas in the spinels with selenium the corresponding clusters are antiferromagnetic and the giant magnetoresistance has been observed both positive and negative. A jump-like phase transition was here observed changing both the sign and the measured value of the magnetoresistance from -4433% at 153.2 K up to +980% at 154.24 K. Moreover, in the spinels with selenium both semiconductor-metal and metal-semiconductor phase transitions have been observed from the temperature dependence of the resistance.

  16. Half metallicity and magnetic properties of CrO{sub 2} doped with Ti, Sn or Ru

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, C. [The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Lu, Z., E-mail: zludavid@live.com [The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Liu, S. [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Gan, Z.; Guo, F. [The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Xiong, R., E-mail: xiongrui@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Mei, X. [School of Science, Wuhan University of Technology, Wuhan 430070 (China); Liu, H. [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Shi, J., E-mail: jshi@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

    2016-11-01

    It is possible to stabilize CrO{sub 2} internally by doping with element such as Ti, Sn or Ru which has stable rutile structured oxide. However, the half metallicity and magnetic properties of CrO{sub 2} may also change when doped with different elements. In this study, by using first principle method, the electronic structure and magnetic properties of CrO{sub 2} doped with different amounts and different types (Ti, Sn or Ru) of dopants were studied. It was found that when doped with Ti or Sn, the half metallicity of CrO{sub 2} will keep intact even at very high dopant concentration, while for Ru-doped CrO{sub 2}, the half metallicity will only be maintained at low Ru concentration. Besides, the half metallicity of Ru-doped CrO{sub 2} also depends on the relative positions of Ru atoms – the half metallicity may be destroyed even at low Ru concentration if two Ru ions are very close to each other. The magnetic properties of doped CrO{sub 2} also show dependence on dopant concentration and dopant type. The magnetocrystalline anisotropy (MAC) of Ru-doped is found to be very sensitive to both Ru concentration and relative positions of Ru atoms. Large MAC may be induced by Ru doping. - Highlights: • First principle study of Ti, Sn or Ru doped CrO{sub 2} found that the half metallic nature of CrO{sub 2} will keep intact when doped with Ti or Sn, while it may be destroyed when doped with Ru. • The half metallicity of Ru-doped CrO{sub 2} depends on Ru concentration as well as the relative positions of Ru ions. • The magentic properties of doped CrO{sub 2} show dependence on both dopant concentration and dopant type. • Large magnetocrystalline anisotropy may be induced in Ru-doped CrO{sub 2}.

  17. Optimization of thermomechanical processes in Cu-Cr-Zr lead frame alloy using neural networks and genetic algorithms

    Institute of Scientific and Technical Information of China (English)

    SU; Juanhua; LIU; Ping; DONG; Qiming; LI; Hejun

    2005-01-01

    The thermomechanical treatment process is effective in enhancing the properties of the lead frame copper alloy. In this study, an optimal pattern of the thermomechanical processes for Cu-Cr-Zr was investegated using an intelligent control technique consisting of neural networks and genetic algorithms. The input parameters of the artificial neural network (ANN) are the reduction ratio of cold rolling, aging temperature and aging time. The outputs of the ANN model are the two most important properties of hardness and conductivity. Based on the successfully trained ANN model,genetic algorithms (GA) are used to optimize the input parameters of the model and select perfect combinations of thermomechanical processing parameters and properties.The good generalization performance and optimized results of the integrated model are achieved.

  18. Sulfidation as a natural antidote to metallic nanoparticles is overestimated: CuO sulfidation yields CuS nanoparticles with increased toxicity in medaka (Oryzias latipes) embryos.

    Science.gov (United States)

    Li, Lingxiangyu; Hu, Ligang; Zhou, Qunfang; Huang, Chunhua; Wang, Yawei; Sun, Cheng; Jiang, Guibin

    2015-02-17

    Sulfidation is considered as a natural antidote to toxicity of metallic nanoparticles (NPs). The detoxification contribution from sulfidation, however, may vary depending on sulfidation mechanisms. Here we present the dissolution-precipitation instead of direct solid-state-shell mechanism to illustrate the process of CuO-NPs conversion to CuS-NPs in aqueous solutions. Accordingly, the CuS-NPs at environmentally relevant concentrations showed much stronger interference on Japanese medaka (Oryzias latipes) embryo hatching than CuO-NPs, which was probably due to elevated free copper ions released from CuS-NPs, leading to significant increase in oxidative stress and causing toxicity in embryos. The larval length was significantly reduced by CuS-NPs, however, no other obviously abnormal morphological features were identified in the hatched larvae. Co-introduction of a metal ion chelator [ethylene diamine tetraacetic acid (EDTA)] could abolish the hatching inhibition induced by CuS-NPs, indicating free copper ions released from CuS-NPs play an important role in hatching interference. This work documents for the first time that sulfidation as a natural antidote to metallic NPs is being overestimated, which has far reaching implications for risk assessment of metallic NPs in aquatic environment.

  19. Tunneling-MR in Fe-Cr-O metal-nonmetal granular systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yapi; Xi Li; Liu Chunming; Ge Shihui E-mail: zhangzz@lzu.edu.cngesh@lzu.edu.cn

    2001-05-01

    Tunneling magnetoresistance (TMR) has been achieved for Fe-Cr-O granular films prepared by RF cosputtering methods. These films are composed of nanoscaled Fe granules with an average diameter of 18-28 nm embedded in the crystalline insulating Cr{sub 2}O{sub 3} matrix, and Fe volume fraction f{sub v} ranges from 15% to 55%. Ferromagnetic properties exist in all samples. With the decrease of f{sub v}, TMR increases from -0.24% for f{sub v}=55% to -1.9% for f{sub v}=39%, the maximum, then decreases to -0.23% at f{sub v}=28%. It is interesting that TMR becomes positive 2% at f{sub v}=15%. The relationship between ln{rho}(0) and 1/T{sup 1/2} shows a clear linear relation in the temperature range from 200 to 290 K for the sample with the maximum negative TMR, indicating a tunneling conductive mechanism. Beyond this temperature range (5-200 K) the relationship is obviously nonlinear, implying that some other effects may exist, which needs to be further studied. Our results imply that superparamagnetic state of the metal granules is not the necessary condition for TMR, and it may not be the main factor affecting the TMR, while the microstructure of films, such as the interfaces between the metal and oxide may be important to TMR as the electronic structure of metal-oxide interface can influence the spin polarization.

  20. Tunable Electrical Conductivity and Magnetic Property of the Two Dimensional Metal Organic Framework [Cu(TPyP)Cu2(O2CCH3)4].

    Science.gov (United States)

    Sengupta, Ananya; Datta, Subhadeep; Su, Chenliang; Herng, Tun Seng; Ding, Jun; Vittal, Jagadese J; Loh, Kian Ping

    2016-06-29

    The coordination chemistry between copper acetate [Cu2(OAc)4] and 5,10,15,20-tetra-4-pyridyl-21H,23H-porphine (porphyrin, H2TPyP) is found to give rise to either a 2D metal-organic framework (MOF) [Cu(TPyP)Cu2(O2CCH3)4] or a 3D MOF [Cu(TPyP)CuCl2]·2.5TCE·7H2O], depending on the choice of solvent. The 2D MOF can be made into a film, which was doped with 7,7,8,8-tetracyanoquinodimethane (TCNQ), and the electrical conductivity of the thin film was increased by 3 orders of magnitude with respect to that of the undoped Cu-MOF. The formation of a charge-transfer complex between TCNQ and the 2D Cu-MOF also imparts stronger paramagnetic properties than for the undoped MOF.

  1. Microstructural evolution of 12Cr-2W-Cu-V-Nb steel during three-year service exposure

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, K.

    2000-11-01

    Microstructural evolution of 12Cr-2W-Cu-V-Nb steel tubes (ASME SA213-T122) after one-year and three-year service exposure tests in a Japanese practical boiler has been investigated from a standpoint of the phase stability of precipitates. The test tubes consist of tempered martensite and {delta}-ferrite, and the main precipitates are MX-type carbonitride, M{sub 23}C{sub 6} carbide and Laves phase. TEM observations on thin films show that the MX has precipitated in a plate-shaped with a coherent or semi-coherent relationship with the matrix inside grains. An estimation of the lattice misfit between MX and the matrix suggests that the coherent strain has been high enough to enhance the shear stress and then strongly interact with dislocations. Another important point is that morphology and compositions of MX have been stable under the present service conditions, thereby the creep strength as well as tensile strength has kept high after long-term service exposure. The long-term exposure to the present service temperature has enhanced the precipitation of Fe{sub 2}(W, Mo) Laves phase inside grains, resulting in a marked reduction in the dissolved W and Mo in matrix. It is found that the kinetics of W-partitioning between matrix and Laves phase can be successfully expressed by the Johnson-Mehl-Avrami type equation and applied to estimate the actual temperatures of the exposed tubes. It is concluded that the kinetics of Laves phase precipitation and morphology of MX have mainly controlled a microstructural stability in the 12Cr-2W-Cu-V-Nb steel, and also give helpful suggestion to increase the creep resistance during the long-term service exposure. (author)

  2. Dealloying of Cu-Based Metallic Glasses in Acidic Solutions: Products and Energy Storage Applications

    Directory of Open Access Journals (Sweden)

    Zhifeng Wang

    2015-04-01

    Full Text Available Dealloying, a famous ancient etching technique, was used to produce nanoporous metals decades ago. With the development of dealloying techniques and theories, various interesting dealloying products including nanoporous metals/alloys, metal oxides and composites, which exhibit excellent catalytic, optical and sensing performance, have been developed in recent years. As a result, the research on dealloying products is of great importance for developing new materials with superior physical and chemical properties. In this paper, typical dealloying products from Cu-based metallic glasses after dealloying in hydrofluoric acid and hydrochloric acid solutions are summarized. Several potential application fields of these dealloying products are discussed. A promising application of nanoporous Cu (NPC and NPC-contained composites related to the energy storage field is introduced. It is expected that more promising dealloying products could be developed for practical energy storage applications.

  3. Remarkably stable amorphous metal oxide grown on Zr-Cu-Be metallic glass.

    Science.gov (United States)

    Lim, Ka Ram; Kim, Chang Eun; Yun, Young Su; Kim, Won Tae; Soon, Aloysius; Kim, Do Hyang

    2015-12-14

    In the present study, we investigated the role of an aliovalent dopant upon stabilizing the amorphous oxide film. We added beryllium into the Zr50Cu50 metallic glass system, and found that the amorphous oxide layer of Be-rich phase can be stabilized even at elevated temperature above Tg of the glass matrix. The thermal stability of the amorphous oxide layer is substantially enhanced due to Be addition. As confirmed by high-temperature cross-section HR-TEM, fully disordered Be-added amorphous layer is observed, while the rapid crystallization is observed without Be. To understand the role of Be, we employed ab-initio molecular dynamics to compare the mobility of ions with/without Be dopant, and propose a disordered model where Be dopant occupies Zr vacancy and induces structural disorder to the amorphous phase. We find that the oxygen mobility is slightly suppressed due to Be dopant, and Be mobility is unexpectedly lower than that of oxygen, which we attribute to the aliovalent nature of Be dopant whose diffusion always accompany multiple counter-diffusion of other ions. Here, we explain the origin of superior thermal stability of amorphous oxide film in terms of enhanced structural disorder and suppressed ionic mobility due to the aliovalent dopant.

  4. Hetero-metal cation control of CuO nanostructures and their high catalytic performance for CO oxidation

    Science.gov (United States)

    Huang, Hongwen; Zhang, Liqiang; Wu, Kewei; Yu, Qing; Chen, Ru; Yang, Hangsheng; Peng, Xinsheng; Ye, Zhizhen

    2012-11-01

    A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous CuO quasi-monocrystalline nanosheets prepared at 25 °C with a thickness of ca. 10 nm and large specific surface area of 80.32 m2 g-1 is investigated intensively. These CuO nanosheets demonstrate a superior catalytic activity for CO oxidation, with features of high CO conversion efficiency (47.77 mmolCO g-1CuO h-1 at 200 °C), which is close to that reported for previously investigated supported-CuO catalysts, and a low apparent activation energy Ea (53.3 kJ mol-1).A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous Cu

  5. Concentrations of heavy metals (Mn, Co, Ni, Cr, Ag, Pb) in coffee.

    Science.gov (United States)

    Nędzarek, Arkadiusz; Tórz, Agnieszka; Karakiewicz, Beata; Clark, Jeremy Simon; Laszczyńska, Maria; Kaleta, Agnieszka; Adler, Grażyna

    2013-01-01

    Technologies involved in roasting coffee beans, as well as the methods used to prepare infusions, vary according to culture, and contribute to differences in the concentration of elements in the drink. Concentrations of six elements: manganese (Mn), cobalt (Co), nickel (Ni), chrome (Cr), silver (Ag) and lead (Pb) were investigated in coffee infusions from eleven samples of coffee, roasted and purchased in four countries: Bosnia and Herzegovina, Brazil, Lebanon and Poland. Metal concentrations were determined using an induction coupled plasma technique in combination with mass spectrometry (ICP-MS, Perkin Elmer) which measures total metal (ionic and non-ionic) content. Metal intake estimated for individual countries (in the respective order; mean consumption per person per year) was as follows: Mn: 26.8-33.1, 28.3-29.5, 29.7, 12.6-18.9 mg; Co: 0.33-0.48, 0.42-0.35, 0.32, 0.12-0.17 mg; Ni: 3.83-5.68, 4.85-5.51, 4.04, 2.06-2.24 mg; Cr: 0.17-0.41, 0.21-0.47, 0.17, 0.09-0.28 mg; Ag: 0.16-1.13, 0.26-0.70, 0.61, 0.33-1.54 mg, Pb: 4.76-7.56, 3.59-5.13, 3.33, 1.48-2.43 mg. This finding gives new data for Mn, Co, Ni, Cr, and Ag intake from coffee , and suggests that the amounts are negligible. However, the data for Pb consumption in heavy drinkers, for example in Bosnia and Herzegovina, indicate that Pb intake from coffee may contribute to the disease burden. The high lead level in some coffees suggests the need for a more precise control of coffee contamination.

  6. Visible light CrO4(2-) reduction using the new CuAlO2/CdS hetero-system.

    Science.gov (United States)

    Brahimi, R; Bessekhouad, Y; Nasrallah, N; Trari, M

    2012-06-15

    In this study, 64% of hexavalent chromium Cr(VI) reduction from the initial concentration (10(-4) M) is reported under visible light using the (CuAlO(2)/CdS) hetero-system. In this new hetero-system, low doped CuAlO(2) delafossite, synthesized by sol-gel works as an electrons reservoir with a wide space charge region (440 nm). In this case, the electron transfer to chromate is mediated via the hexagonal CdS variety, whose conduction band level is at -1.08 V with respect to the saturated calomel electrode which is more negative than the CrO(4)(2-)/Cr(3+) level. This high reduction rate is achieved under optimized pH and CuAlO(2) percentage. Moreover, salicylic acid gives the best performance among hole scavengers and CuAlO(2) approaches 100% photostability at pH 7.5. The photo-catalytic process follows a pseudo first order kinetic with a half life of 2h. The reaction products are identified by UV-visible spectrophotometry and linear voltametry at a platinum rotating electrode. The results reveal the presence of Cr(3+) after irradiation.

  7. Use of anomalous scattering for synchrotron X-ray reflectivity studies of Fe-Cr and Co-Cu double layers

    CERN Document Server

    Prokert, F; Gorbunov, A

    2003-01-01

    Double layers of Fe-Cr and Co-Cu, respectively, were prepared on oxidized Si substrates by pulsed laser deposition (PLD). The interfacial roughness structure was studied by synchrotron X-ray reflectivity measurements at the absorption K-edges using the contrast enhancement due to resonant scattering. The results are determined from simulations of the measured specular and diffuse scans. Whereas in Fe-Cr double layers the sigma sub r sub m sub s -interface width for Fe deposition on Cr (sigma sub C sub r =0.70+-0.1 nm) is not very different from that of Cr deposition on Fe (sigma sub F sub e =0.85+-0.1 nm), in Co-Cu double layers, in contrast, for Cu deposition on Co, the width (sigma sub C sub o =0.65+-0.1 nm) is much smaller than for Co deposition on Cu (sigma sub C sub u =1.5+-0.15 nm). On the basis of the fractal model to describe the interface roughness morphology, from the off-specular scans the lateral roughness correlation length, xi and the roughness exponent, h, were determined. For both types of dou...

  8. Mechanical Properties and Corrosion-Abrasion Wear Behavior of Low-Alloy MnSiCrB Cast Steels Containing Cu

    Science.gov (United States)

    Luo, Kaishuang; Bai, Bingzhe

    2011-01-01

    Two medium carbon low-alloy MnSiCrB cast steels containing different Cu contents (0.01 wt pct and 0.62 wt pct) were designed, and the effect of Cu on the mechanical properties and corrosion-abrasion wear behavior of the cast steels was studied. The results showed that the low-alloy MnSiCrB cast steels obtained excellent hardenability by a cheap alloying scheme. The microstructure of the MnSiCrB cast steels after water quenching from 1123 K (850 °C) consists of lath martensite and retained austenite. After tempering at 503 K (230 °C), carbides precipitated, and the hardness of the cast steels reached 51 to 52 HRC. The addition of Cu was detrimental to the ductility and impact toughness but was beneficial to the wear resistance in a corrosion-abrasion wear test. The MnSiCrB cast steel with Cu by the simple alloying scheme and heat treatment has the advantages of being high performance, low cost, and environmentally friendly. It is a potential, advanced wear-resistant cast steel for corrosion-abrasion wear conditions.

  9. Simultaneous removal of As, Cd, Cr, Cu, Ni and Zn from stormwater using high-efficiency industrial sorbents: Effect of pH, contact time and humic acid

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Mikkelsen, Peter Steen; Ledin, Anna

    2016-01-01

    The effect of contact time, solution pH, and the presence of humic acid (HA) on the combined removal of As, Cd, Cr, Cu, Ni and Zn is investigated in batch tests using alumina, granulated activated carbon (GAC), and bauxsol coated sand (BCS) as sorbents. It is found that the equilibrium time for Cd...

  10. Effect of 0.5 wt % Cu addition in Sn-3.5%Ag solder on the dissolution rate of Cu metallization

    Science.gov (United States)

    Alam, M. O.; Chan, Y. C.; Tu, K. N.

    2003-12-01

    The dissolution of thin film under-bump-metallization (UBM) by molten solder has been one of the most serious processing problems in electronic packaging technology. Due to a higher melting temperature and a greater Sn content, a molten lead-free solder such as eutectic SnAg has a faster dissolution rate of thin film UBM than the eutectic SnPb. The work presented in this paper focuses on the role of 0.5 wt % Cu in the base Sn-3.5%Ag solder to reduce the dissolution of the Cu bond pad in ball grid array applications. We found that after 0.5 wt % Cu addition, the rate of dissolution of Cu in the molten Sn-3.5%Ag solder slows down dramatically. Systematic experimental work was carried out to understand the dissolution behavior of Cu by the molten Sn-3.5%Ag and Sn-3.5%Ag-0.5%Cu solders at 230-250 °C, for different time periods ranging from 1 to 10 min. From the curves of consumed Cu thickness, it was concluded that 0.5 wt % Cu addition actually reduces the concentration gradient at the Cu metallization/molten solder interface which reduces the driving force of dissolution. During the dissolution, excess Cu was found to precipitate out due to heterogeneous nucleation and growth of Cu6Sn5 at the solder melt/oxide interface. In turn, more Cu can be dissolved again. This process continues with time and leads to more dissolution of Cu from the bond pad than the amount expected from the solubility limit, but it occurs at a slower rate for the molten Sn-3.5%Ag-0.5%Cu solder.

  11. Parallel Molecular Dynamics Simulations of Ejection from the Metal Cu and Al Under Shock Loading

    Institute of Scientific and Technical Information of China (English)

    CHEN Qi-Feng; CAO Xiao-Lin; ZHANG Ying; CAI Ling-Cang; CHEN Dong-Quan

    2005-01-01

    @@ Large-scale non-equilibrium molecular dynamics simulations are used to investigate the ejection of the metal under a shock loading. The present work focus on the dynamic process of ejection from the metal Cu and Al surface groove under shock loading, using parallel MD implementation and the Morse potential. The ejected mass coefficient and the size distribution of ejected particles (cluster for atoms) are investigated with changes of the half-angle or the depth of groove and shock strength.

  12. Percolation metal-insullator transition in BiSrCaCuO films

    Science.gov (United States)

    Okunev, V. D.; Pafomov, N. N.; Svistunov, V. M.; Lewandowski, S. J.; Gierlowski, P.; Kula, W.

    1996-02-01

    An experimental investigation of the metal-insulator trnasition in BiSrCaCuO (BSCCO) films is reported. We performed resistivity, optical-absorption and critical-temperature measurements on several samples obtained by different technological methods. The results agree well with the percolation mechanism of the metal-insulator transition and show interesting correlations between room-temperature conductivity and superconducting properties of the investigated films.

  13. [Determination of Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES].

    Science.gov (United States)

    Yang, X

    1997-06-01

    A method of simultaneous and direct determination for Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES is reported. The spectral interferences and effect of acidity have been investigated. Working conditions were optimized. The method has been applied to the analysis of silver brazing filler metals with RSD of 4-7% and recovery of 94-105%. This method was accurate, simple and rapid.

  14. Microstructure and Mechanical Properties of Co21Cr22Cu22Fe21Ni14 Processed by High Pressure Torsion and Annealing

    Science.gov (United States)

    Park, Nokeun; Li, Xiang; Tsuji, Nobuhiro

    2015-08-01

    The strengthening mechanisms of Co21Cr22Cu22Fe21Ni14 multiple-principal element alloy processed by high pressure torsion (HPT) and annealing were examined. Two face-centered cubic (FCC) phases were observed in the as-cast alloy; one was a Cu-rich phase and the other was a Cu-lean one. In the HPT process, the microhardness increased from 190 HV to 470 HV at a strain of 157 due to strain hardening and grain refinement hardening. X-ray diffraction showed that the lattice parameters of the two FCC phases became closer to each other at higher HPT strain, indicating the alloying of Cu into the Cu-lean matrix. The HPT processed specimens were annealed at 500°C, 550°C, 600°C, and 650°C. The microhardness increased to 540 HV after annealing at temperatures lower than 650°C, whereas it decreased when the specimen was annealed at 650°C. The mean grain size of the specimens annealed at temperatures lower than 650°C was much smaller than 100 nm, and Cu-rich clusters with sizes ranging from 2 nm to 32 nm were distributed homogeneously. The reasons for the formation of the Cu-rich nano-clusters were discussed from a perspective of the positive mixing enthalpy of Cu in the alloy and thermalenergy for Cu diffusion at a given temperature. The dissolution and partitioning of two FCC phases played a key role in strengthening the Co21Cr22Cu22Fe21Ni14 system.

  15. Determination of metals (As, Cu, Fe, and Zn in two fish species from the Miankaleh wetland

    Directory of Open Access Journals (Sweden)

    Alipour Hossein

    2016-06-01

    Full Text Available The objective of this study was to determine the concentrations As, Cu, Fe, and Zn in the livers, gills, and muscles of vobla or Caspian roach, Rutilus caspicus (Yakovlev, and bighead goby, Neogobius gorlap (Iljin, from the Miankaleh wetland. The results showed that metal accumulation in the liver tissues was higher than in the gills and muscles for all metals, and Fe concentration was higher than Zn, Cu, and As in all the tissues studied. The concentrations of As, Cu, Fe, and Zn in the livers, gills, and muscles of bighead goby were higher than in vobla tissues, except for concentrations of As in the muscles. Fe, Cu, and Zn concentrations in the muscles were below the maximum permissible limit of the WHO and the FAO for both species, but the concentration of As in the muscles of both species exceeded the permissible limit proposed by the FAO; thus, human consumption should be limited. The levels of the other metals (Fe, Cu and Zn were completely safe.

  16. Hopping and Non-universal Conductivity in Half-Metallic CrO2 Composites

    Institute of Scientific and Technical Information of China (English)

    陈亚杰; 张晓渝; 蔡田怡; 李振亚

    2003-01-01

    We study the dependence of resistivity p on conducting volume fraction p in CrO2/TiO2 magnetic composite that is composed of acicular half-metallic particles and spherical insulating particles. The measured percolation threshold was determined to be pc = 0.192. It is found that the conductivity exhibits a non-universal critical exponent t = 2.52 ± 0.08, which may be dominantly attributed to microstructure and higher-order hopping in this composite.

  17. Microstructure and pitting corrosion of 13CrNiMo weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Bilmes, P.D. [Laboratorio de Investigaciones de Metalurgia Fisica ' Ing. Gregorio Cusminsky' (LIMF), Departamento Mecanica, Facultad de Ingenieria, Universidad Nacional de la Plata, calle 1 y 47, 1900 La Plata (Argentina); Llorente, C.L. [Laboratorio de Investigaciones de Metalurgia Fisica ' Ing. Gregorio Cusminsky' (LIMF), Departamento Mecanica, Facultad de Ingenieria, Universidad Nacional de la Plata, calle 1 y 47, 1900 La Plata (Argentina); Saire Huaman, L. [Instituto de Investigaciones, Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de la Plata, Sucursal 4-C.C. 16, 1900 La Plata (Argentina); Laboratorio de Ingenieria de Corrosion y Tecnologia Electroquimica (LICTE), Departamento Ingenieria Quimica, Facultad de Ingenieria, Universidad Nacional de la Plata, 1 y 47, 1900 La Plata (Argentina); Gassa, L.M. [Instituto de Investigaciones, Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de la Plata, Sucursal 4-C.C. 16, 1900 La Plata (Argentina); Laboratorio de Ingenieria de Corrosion y Tecnologia Electroquimica (LICTE), Departamento Ingenieria Quimica, Facultad de Ingenieria, Universidad Nacional de la Plata, 1 y 47, 1900 La Plata (Argentina); Gervasi, C.A. [Instituto de Investigaciones, Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de la Plata, Sucursal 4-C.C. 16, 1900 La Plata (Argentina) and Laboratorio de Ingenieria de Corrosion y Tecnologia Electroquimica (LICTE), Departamento Ingenieria Quimica, Facultad de Ingenieria, Universidad Nacional de la Plata, 1 y 47, 1900 La Plata (Argentina)]. E-mail: gervasi@inifta.unlp.edu.ar

    2006-10-15

    Cyclic potentiodynamic measurements and scanning electron microscopy were used to analyze susceptibility to pitting corrosion of 13CrNiMo weld metals. In order to carry out a critical assessment of the influence of microstructural factors on localized corrosion, different heat treatments were applied to the alloys under investigation. Volume fractions of austenite in tempered conditions as well as the amount and size of precipitated carbides strongly affect pitting resistance. Characteristic potentials (pitting potential and repassivation potential) increase according to the retained austenite content. Results can be discussed in terms of a model that describes the structural refinement resulting from a double-tempering procedure.

  18. Treatment technologies used for the removal of As, Cr, Cu, PCP and/or PCDD/F from contaminated soil: A review.

    Science.gov (United States)

    Guemiza, Karima; Coudert, Lucie; Metahni, Sabrine; Mercier, Guy; Besner, Simon; Blais, Jean-François

    2017-07-05

    The contamination of soils by metals such as arsenic, chromium, copper and organic compounds such as pentachlorophenol (PCP) and dioxins and furans (PCDD/F) is a major problem in industrialized countries. Excavation followed by disposal in an appropriate landfilling is usually used site to manage these contaminated soils. Many researches have been conducted to develop physical, biological, thermal and chemical methods to allow the rehabilitation of contaminated sites. Thermal treatments including thermal desorption seemed to be the most appropriate methods, allowing the removal of more than 99.99% of organic contaminants but, they are ineffective for inorganic compounds. Biological treatments have been developed to remove inorganic and hydrophobic organic contaminants but their applications are limited to soils contaminated by easily biodegradable organic compounds. Among the physical technologies available, attrition is the most commonly used technique for the rehabilitation of soils contaminated by both organic and inorganic contaminants. Chemical processes using acids, bases, redox agents and surfactants seemed to be an interesting option to simultaneously extract organic and inorganic contaminants from soils. This paper will provide an overview of the recent developments in the field of decontamination technologies applicable for the removal of As, Cr, Cu, PCP and/or PCDD/F from contaminated soils. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Deformation mechanisms to ameliorate the mechanical properties of novel TRIP/TWIP Co-Cr-Mo-(Cu) ultrafine eutectic alloys.

    Science.gov (United States)

    Kim, J T; Hong, S H; Park, H J; Kim, Y S; Suh, J Y; Lee, J K; Park, J M; Maity, T; Eckert, J; Kim, K B

    2017-01-09

    In the present study, the microstructural evolution and the modulation of the mechanical properties have been investigated for a Co-Cr-Mo (CCM) ternary eutectic alloy by addition of a small amount of copper (0.5 and 1 at.%). The microstructural observations reveal a distinct dissimilarity in the eutectic structure such as a broken lamellar structure and a well-aligned lamellar structure and an increasing volume fraction of Co lamellae as increasing amount of copper addition. This microstructural evolution leads to improved plasticity from 1% to 10% without the typical tradeoff between the overall strength and compressive plasticity. Moreover, investigation of the