检索结果-南通市图书馆

Rare metals 2006年第z1期25卷 400-404页

作者： LI Jingyong LI Jianguo ZHENG Huiling LI Chengshan LU Yafeng ZHOU Lian Advanced Welding Technology Provincial key laboratory Jiangsu University of Science and Technology Zhenjiang 212003 China Northwest Institute for nonferrous metal Research Xi''an 710016 China Advanced Welding Technology Provincial Key Laboratory Jiangsu University of Science and Technology Zhenjiang 212003 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China

The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route.

关键词： (Bi,Pb)-2223/Ag tape cooling rate decomposition and reformation

Pretreatment of lead anode slime with low silver by vacuum distillation for concentrating silver

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2013年第3期20卷 615-621页

作者：李亮田阳刘大春周厚军戴永年杨斌 National Engineering laboratory for Vacuum metallurgy (Kunming University of Science and Technology) State key laboratory Breeding Base of Complex Non-ferrous metal resources Clear Utilization key laboratory for nonferrous Vacuum metallurgy of Yunnan Province

The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically. The volatilization rates and mass fractions of elements, influenced by distillation temperature, heat preservation time and material thickness, were investigated under laboratory conditions. The experimental results indicate that almost all of lead and bismuth can be separated from silver-contained multicomponent alloy at 1 223 K for 45 min when the chamber pressure maintains at 10-25 Pa. Silver can be easily enriched in the residue and its mass fraction increases from 3.6% to 27.8% when the distillation temperature is between 1 133 K and 1 373 K. Due to the forming ofintermetallic compounds Cu2Sb, Cul0Sb3 and Ag3Sb, the antimony could not be evaporated completely during the vacuum distillation. EDS analysis indicates that the condensate has a columnar crystal structure.

关键词： Ag-contained multicomponent alloy vacuum distillation separation intermetallic compounds

Electrochemical performance of alloys Ho_5Fe_3Co_(12) and Ho_(33.3)Co_(66.7)

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2010年第4期28卷 618-621页

作者：赵允红何维张永志曾令民 key laboratory of nonferrous metal Materials and New Processing Technology College of Materials Science and Engineering Guangxi University

Alloys with composition Ho5Fe3Co12 and Ho33.3Co66.7 were prepared and examined by X-ray diffractometer and automatic battery testing instrument. The electrochemical properties of these alloys such as discharge capacity, cycling performance and high rate dischargeability were investigated by battery testing instruments in alkaline electrolyte. A comparison of the electrochemical performance of the Ho5Fe3Co12 and Ho33.3Co66.7 alloys revealed that alloy Ho5Fe3Co12 possessed a better electrochemical performance...

关键词： rare earth alloys electrochemical performance X-ray diffraction

Growth and Characterization of Doped CeO_2 Buffers on Ni-W Substrates for Coated Conductors Using metal Organic Deposition Method

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2012年第3期27卷 471-476页

作者：王耀卢亚锋 Northwest Institute for nonferrous metal Research State key laboratory of Solidification Processing Northwestern Polytechnical University

CeO2 and Ce0.8M0.2O2-d films （M = Mn, Y, Gd, Sm, Nd and La） with （00l） preferred orientation have been prepared on biaxially textured Ni-W substrates by metal organic decomposition （MOD） method. The factors influencing the formation of cracks on the surface of these CeO2 and doped CeO2 films on Ni-W substrates were explored by X-ray diffraction （XRD）, scanning electron microscopy （SEM） analysis, atomic force microscopy （AFM） and differential scanning calorimetry （DSC）. The results indicate that many factors, such as the change of the ionic radii of doping cations, the transformation of crystal structure and the formation of oxygen vacancies in lattices at high annealing temperature, may be related to the formation of cracks on the surface of these films. However, the crack formation shows no dependence on the crystal lattice mismatch degree of the films with Ni-W substrates. Moreover, the suppression of surface cracks is related to the change of intrinsic elasticity of CeO2 film with doping of cations with a larger radius. SEM and AFM investigations of Ce0.8M0.2O2-d （M = Y, Gd, Sm, Nd and La） films reveal the dense, smooth and crack-free microstructure, and their lattice parameters match well with that of YBCO, illuminating that they are potentially suitable to be as buffer layer, especially as cap layer in multi-layer architecture of buffer layer for coated conductors.

关键词： coated conductors buffer layer metal organic deposition

Effects of trace Cr on as-cast microstructure and microstructural evolution of semi-solid isothermal heat treatment ZC61 magnesium alloy

在线全文

学校读者我要写书评

暂无评论

China Foundry 2019年第1期16卷 53-62页

作者： Xiao-feng Huang Ya-jie Ma Qiao-qiao Zhang Lang-lang Wei Jian-qiao Yang State key laboratory of Advanced Processing and recycling of nonferrous metals Lanzhou University of TechnologyLanzhou 730050China

The content and kind of trace elements in magnesium alloys have important effects on their ascast and semi-solid microstructures. In this research work, effects of trace Cr on as-cast and semi-solid microstructures of ZC61 magnesium alloy were investigated by metal mold casting and semi-solid isothermal heat treatment. The results show that the addition of Cr can refine the α-Mg phase without generating a new phase, noticeably change the eutectic phase, and decrease the average size of solid particles at the same isothermal heat treatment conditions. Non-dendritic microstructures of all alloys are constituted of α_1-Mg phases, α_2-Mg phases and eutectic phases after water quenching. With isothermal temperature increased or holding time prolonged, the eutectic microstructure(α-Mg+MgZn_2+CuMgZn) at the grain boundaries in as-cast alloy is melted preferentially and then turned into semi-solid non-dendritic microstructure by processes of initial coarsening, microstructure separation, spheroidizing and final coarsening. Especially when the ZC61-0.1 Cr alloy was treated at 585 ℃ for 30 min, the ideal non-dendritic microstructure can be obtained, and the corresponding solid particle size and shape factor were 37.5 μm and 1.33, respectively. The coarsening process of solid α-Mg phase at higher temperature or longer time, which is affected by both combining growth and Ostwald ripening mechanism, is refrained when Cr is added to the ZC61 alloy.

关键词： ZC61 magnesium alloy Cr content semi-solid isothermal heat treatment non-dendritic microstructure microstructural evolution

Effects of Cu addition on microstructureand mechanical properties of as-cast Mg-6Znmagnesium alloy

在线全文

学校读者我要写书评

暂无评论

China Foundry 2017年第4期14卷 251-257页

作者： Yu Zhang Xiao-feng Huang Ying Ma Ti-jun Chen Yuan-dong Li Yuan Hao State key laboratory of Advanced Processing and recycling of nonferrous metals Lanzhou University of TechnologyLanzhou 730050China

The application of Mg-Zn binary alloys is restricted due to their developed dendritic microstructure and poor mechanical properties. In this study, an alloying method was used to improve the mechanical properties of Mg-Zn alloy. The Mg-6Zn magnesium alloys microalloyed with varying Cu content(0, 0.8, 1.5, 2.0 and 2.5wt.%) were fabricated by permanent mould casting, and the effects of Cu content on the microstructure and mechanical properties of as-cast Mg-6Zn alloys were studied using OM, SEM, XRD and tensile tests at room temperature. The obtained results show that the addition of Cu not only can refine the grains effectively, but also can modify the eutectic morphology and improve the mechanical properties of the alloys. The main phases of the studied alloys include α-Mg, MgZn_2, Mg_2Cu and CuMgZn. When the content of Cu exceeds 0.8wt.%, Mg_2Cu phase appears. Meanwhile, the eutectic morphology is modified into dendritic shape or lamellar structure, which has an adverse effect on the tensile properties. Furthermore, among the investigated alloys, the alloy containing 0.8% Cu shows an optimalultimate tensile strength of 196 MPa, while the alloy with 1.5wt.% Cu obtains an excellent elongation of 7.22%. The experimental alloys under different Cu contents show distinguishing fracture behaviors: the fracture of the alloy with 0.8wt.% Cu reveals a mixed mode of inter-granular and quasi-cleavage, while in other investigated alloys, the fracture behaviors are dominated by cleavage fracture.

关键词： Mg-Zn magnesium alloy Cu addition microstructure mechanical property fracture mode

Dynamic flow resistivity based model for sound absorption of multi-layer sintered fibrous metals

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第11期57卷 2096-2105页

作者： MENG Han AO QingBo TANG HuiPing XIN FengXian LU TianJian State key laboratory for Mechanical Structure Strength and Vibration School of Aerospace Xi'an Jiaotong University State key laboratory of Porous metal Materials Northwest Institute for Nonferrous Metal Research

The sound absorbing performance of the sintered fibrous metallic materials is investigated by employing a dynamic flow resistivity based model,in which the porous material is modeled as randomly distributed parallel fibers specified by two basic physical parameters:fiber diameter and porosity.A self-consistent Brinkman approach is applied to the calculation of the dynamic resistivity of flow perpendicular to the cylindrical *** on the solved flow resistivity,the sound absorption of single layer fibrous material can be obtained by adopting the available empirical ***,the recursion formulas of surface impedance are applied to the calculation of the sound absorption coefficient of multi-layer fibrous *** measurements are conducted to validate the proposed model,with good agreement achieved between model predictions and tested *** calculations with the proposed model are subsequently performed to quantify the influences of fiber diameter,porosity and backed air gap on sound absorption of uniform(single-layer)fibrous *** show that the sound absorption increases with porosity at higher frequencies but decreases with porosity at lower *** sound absorption also decreases with fiber diameter at higher frequencies but increases at lower *** sound absorption resonance is shifted to lower frequencies with air *** multi-layer fibrous materials,gradient distributions of both fiber diameter and porosity are introduced and their effects on sound absorption are *** is found that increasing the porosity and fiber diameter variation improves sound absorption in the low frequency *** model provides the possibility to tailor the sound absorption capability of the sintered fibrous materials by optimizing the gradient distributions of key physical parameters.

关键词： sound absorption sintered fibrous material dynamic flow resistivity

Effects of Sm addition on microstructural evolution of Mg-6Zn-0.4Zr alloy during semi-solid isothermal heat treatment

在线全文

学校读者我要写书评

暂无评论

China Foundry 2017年第2期14卷 85-92页

作者： Yu Zhang Xiao-feng Huang Ying Ma Ti-jun Chen Yuan Hao State key laboratory of Advanced Processing and recycling of nonferrous metals Lanzhou University of Technology Lanzhou 730050 China

The application of segmental semi-solid thixoforming of magnesium alloys is confined due to the dimensional distinction existing in solid particles of the alloy billet from edge to center zones. In the present study, the effects of Sm addition on the microstructural evolution of Mg-6Zn-0.4Zr and Mg-6Zn-4Sm-0.4Zr alloys by semi-solid isothermal heat treatment were investigated, to obtain optimum semi-solid microstructures for the subsequently thixoforming. The results indicate that the grains of the Sm-bearing alloy are evidently refined and gradually evolve from dendritic to globular and elliptic particles. In addition, the distinctly dimensional effect of the Mg-6Zn-0.4Zr alloy is eliminated with 4% Sm addition; the particle sizes in all zones from center to the edge of the billet are almost identical. With the increment of isothermal heat treatment temperature, the dendritic microstructures completely disappear, and meanwhile, the irregular and globular particles gradually form. The size, morphology and the distribution of solid particles mainly depend on the formation and permeation of the liquid phase in the process of isothermal heat treatment. As the isothermal temperature increases from 570 °C to 610 °C, the average size and shape factor of solid particles of both the alloys with and without Sm addition gradually decrease while the liquid fraction gradually increases.

关键词： Mg-Zn-Zr magnesium alloy dimensional effect Sm semi-solid isothermal heat treatment non-dendritic microstructure

Deep eutectic solvent-induced synthesis of Ni-Fe catalyst with excellent mass activity and stability for water oxidation

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2023年第3期8卷 852-863页

作者： Ruichang Xue Mengwei Guo Zhuoming Wei Qibo Zhang key laboratory of Ionic Liquids metallurgy Faculty of Metallurgical and Energy EngineeringKunming University of Science and TechnologyKunming650093China State key laboratory of Complex nonferrous metal resources Cleaning Utilization in Yunnan Province Kunming650093China

Ni-Fe bimetallic electrodes are currently recognized as a kind of benchmark transition metal-based oxygen evolution reaction(OER)*** synthesis of Ni-Fe bimetallic electrode materials with excellent catalytic activity and satisfied stability by a simple and low-cost route is still a big ***,well-defined Ni-Fe nanoparticles in-situ developed on a planar Fe substrate(Ni-Fe NPs/Fe)is fabricated via a facile one-step galvanic replacement reaction(GRR)carried out in an Ethaline-based deep eutectic solvent(DES).The prepared Ni-Fe NPs/Fe exhibits outstanding OER performance,which needs an overpotential of only 319 mV to drive a current density of 10 mA cm^(-2),with a small Tafel slope of 41.2 mV dec^(-1) in 1.0 mol L^(-1) KOH,high mass activity(up to 319.78 A g^(-1) at an overpotential of 300 mV)and robust durability for 200 ***,the Ni-Fe bimetallic oxygen-evolution electrode obtained from the Ethaline-based DES is catalytically more active and durable than that of its counterpart derived from the 4.2 mol L^(-1) NaCl aqueous *** reason for this is mainly related to the different morphology and surface state of the Ni-Fe catalysts obtained from these different solvent environments,particularly for the differences in phy-chemical properties,active species formed and deposition kinetics,offered by the Ethaline-based DES.

关键词： Ni-Fe catalysts Galvanic replacement reaction Deep eutectic solvent Oxygen evolution reaction

Plotting and application of predominance area diagram of Me-S-O system based on topological rules

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第6期23卷 1332-1338页

作者：谢富春尹周澜谭军刘常青张平民 key laboratory of resources Chemistry of nonferrous metals of Ministry of Education (Central South University) Changsha 410083 China Department of Mechanical Engineering Hunan Institute of Engineering Xiangtan 411101 China

The mathematical topological rule was applied to plot the predominance area *** on the analysis of the mutually conjugated,only two diagrams were the best topological embryonic graphs to build the predominance area diagram of Me-S-O *** with topological rules and thermodynamic calculation,four relation-diagrams were denoted asαandβstable and unstable plane-topological diagrams,which were plotted for the Pb-S-O system and Zn-S-O *** results show thatβstable plane-topological diagram of Pb-S-O system andαstable one of Zn-S-O system are in accordance with the traditional predominance area diagram,which indicates that it is feasible to plot the predominance area diagram based on mathematical topological ***,αunstable plane-topological diagram of Pb-S-O system can elucidate the phenomenon that metallic lead exists in higher oxygen and sulfur pressure area in modern bath smelting *** mathematical topological rules broaden the application scope of the predominance area diagram and enrich the practice of its plotting.

关键词： Me-S-O system predominance area diagram topological rules thermodynamic calculation bath smelting