用氯化钠滴定银基合金中的银

通过比较指示电极对的测定精度,拟定一个用银指示电极,Ag-Agl参比电极,氯化钠电位滴定测定纯银及银基合金中银的方法.大量Cu(Ⅱ)、V(Ⅴ)、Ni(Ⅱ)、Al(Ⅲ)、Zn(Ⅱ)、Ce(Ⅲ)、Pb(Ⅱ)的存在不影响银的测定,Pd(Ⅱ)的干扰可在一定酸度下用EDTA配合消除.方法用于银基合金中银的分析,简便,准确.     

电子工业用金基和银基中温钎料的研究进展

由于金基和银基合金钎料蒸气压低,润湿性好,焊接接头强度高,耐腐蚀性优良等特点,使它们成为电子工业中的主要钎焊材料.而熔化温度在400～600℃的电子封装用金基和银基钎料仍是研究的热点.这些钎料都普遍存在加工性不好等问题,给钎料的生产和应用带来了一定的局限性.本文概述了目前应用在电子工业中的金基和银基合金中温钎料的研究进展,同时也从钎料的钎焊特性和加工性能等方面展开了讨论.     

专利信息

一种银基合金／铜／银基合金层状复合钎焊料,一种颗粒增强钛基复合材料的粉末冶金方法     

Au、Ge对银基合金靶材坯料耐硫化性能的协同作用

采用自主设计的带有气氛保护、冒口保温、磁力搅拌和强制冷却功能高频熔炼-铸造-搅拌一体化设备制备银基合金靶材坯料。研究了Au、Ge协同作用对银基合金靶材坯料的组织和性能的影响。结果表明,随着Au、Ge添加量的增加,银基合金靶材微观组织细化,二次枝晶变短,抗硫化性提高,且在Au、Ge添加量均为1.0%(质量分数)时,银基合金靶材坯料的耐硫化性能最佳。随着Au Ge添加量增加,元素偏析现象加剧,在Agl.5Cu0.1Y1.5Au靶材的晶界处出现少量的富集区,使靶材的抗硫化和耐蚀性有所下降。     

湿法制备纳米结构银研究进展

介绍了纳米立方体、三角形纳米棱柱、纳米棒、纳米线、纳米管、树枝状、片状、纳米盘、纳米带等纳米结构银的制备方法,包括溶液还原沉淀法、光诱导转化法、辐射还原法、电化学沉积法、模板法、微波或超声波辅助法、水热法、微乳液法等.并对纳米结构银制备方法存在的问题进行了分析.     

银-铜纳米线的研究和应用进展

银-铜纳米线由于其优良的抗氧化性、机械柔韧性、低廉的成本以及与氧化铟锡相媲美的光电性能,具有广阔的应用前景。基于对30多篇国内外文献的分析,综述了液相还原法、种子介导法、模板法、水热法等制备银-铜纳米线的方法,并探讨了银-铜纳米线在透明导体、复合材料、传感器及催化剂等方面应用。最后,对银-铜纳米线的可控合成及其工业化应用提出了展望。     

透氢钒基合金膜

目前工业上分离高纯氢气应用最多的是致密金属膜,尤其是钯银合金膜。钯、银属于贵金属,大规模应用成本高。钒基合金膜拥有比钯银合金膜更高的透氢率、机械强度和较低的成本,且氢脆抗力较纯钒得到很大提高,成为潜在的替代钯银合金膜的材料之一。本文综述了钒基合金膜材料的研究现状,催化层对透氢性能的影响以及钒基合金膜的制备方法,并对未来的发展趋势进行了展望。     

富银渣中的氯化银转化为单质银

铅阳极泥酸浸富银渣中的银呈氯化银状态。这种状态在下步火法熔炼时会造成损失,因此应首先转化为单质银。作者用置换法或碱处理法使氯化银转化为单质银,转化率９５．４％－９９．６９％,银回收率〉９９．９％。     

电接点材料Ag-Sn-Ce合金研究

采用熔铸和压力加工方法,研制出含少量稀土的新材料Ag-Sn-C??合金.该合金抗熔焊性强,灭弧能力好,电磨损少,温升低.在大功率微动开关和高寿命继电器的试验及应用中表明,新材料完全满足有关技术标准,其电接触性能优于其它银合金,在代替Ag-CdO及Au基合金的应用中结果良好.     

电子组装用低银无铅焊料的研究进展

对目前国内外电子组装用低银无铅焊料最新的研究和应用情况进行了回顾和评述,介绍了低银无铅焊料的现状和其可靠性问题,以及国内外对几种低银无铅焊料进行的研究情况,最后着重分析和展望了低银无铅焊料研究应用的主要发展方向和趋势。     

Kinetics of phase transformations in the surface layer of a binary alloy upon selective dissolution. IV. Ag-Pd|Ag<Superscript>+</Superscript> system

Critical parameters of the morphological development of an electrode surface at the anodic oxidation of silver-based Ag-Pd alloys are estimated. Conditions (potential range and compositions of the alloy and electrolyte solution) of the true selective dissolution of the alloys in an acidic nitrate medium are determined. The nature and kinetic parameters of the nucleation step of the phase transformation of palladium in the surface layer of Ag4Pd and Ag8Pd alloys at the over-critical potentials are found.     

Elemental and phase composition,morphology, and chemical features of the surface of Al–Ni Alloys in contact with liquid Ga–In eutectic

A set of aluminum–nickel alloys has been studied. The elemental composition of the samples has been determined by atomic emission and atomic absorption spectrometry. X-ray diffraction analysis has revealed that the alloying of the metals leads to the formation of Al₃Ni and Al₃Ni₂ intermetallic compounds, while a portion of Al remains in a metallic phase. The local chemical composition and surface morphology of the original alloys and the alloys activated with the liquid Ga–In eutectic have been studied by scanning electron microscopy and X-ray microanalysis. It has been shown that the original alloys are characterized by a pronounced morphological heterogeneity of interfacial regions in the near-surface layers. It has been found that the studied Al–Ni alloys are activated by the liquid Ga–In eutectic; however, one of the alloy components—the Al₃Ni intermetallic compound—does not undergo significant morphological and chemical changes in contact with the liquid eutectic.     

环保型氧化物增强银基电接触功能复合材料研究进展

围绕研制开发具有与AgCdO性能相媲美的银基电接触材柞,报道柚近3年来传统Ag/SnO2、Ag/ZnO、Ag/CuO三种银基电接触材柞体系的研究现状,主要论述国内外研究恘者从掺杂改性、制备方法、材柞模拟仿真、第一性原理计算等方面开展的大柎优化研究;梳理柚目前制备银基电接触材柞体系的常规制备技术及其工作原理;简述柚当前部...     

银基系列电接触复合材料的研发与应用

银基电接触复合材料具有优异的电接触性能,在低压电器、汽车电器和家用电器等行业有广泛的应用。从银基系列电接触复合材料的物理、力学、电学及加工性能等应用要求出发,介绍了银基系列电接触复合材料的制备方法、种类、性能、特点及应用领域,阐述了在已有的银基电接触材料中添加第三组元,改善银基系列电接触复合材料性能的情况。同时介绍了Ag-碳纳米管、Ag-导电陶瓷、Ag-石墨烯等新型银基电接触复合材料的性能、特点及应用领域。     

Interfacial Bonding Strength Between Brazing Alloys and CVD Diamond

Three groups of brazing alloys were compared in brazing chemical-vapor-deposited (CVD) diamond, including two nickel-based alloys (Ni-3Fe-7Cr-3B-0.5Si-0.02C and Ni-14Cr-10P-0.02C), one copper-based alloy (Cu-10Sn-15Ti), and two silver-based alloys (Ag-5Cu-1Al-1.25Ti and Ag-34.25Cu-1In-1.75Ti). The nickel-based alloys catalytically transformed the sp³-bonded diamond into sp²-bonded carbon during high-temperature brazing operation though with the existence of Cr as the active metal. The bonding strength was very low and the fracture primarily propagated through the sp²-bonded carbon. For Cu-10Sn-15Ti brazing alloy, the transformation of the sp³-bonded diamond into sp²-bonded carbon during high-temperature brazing operation was marginal. The bond strength was adequate and fracture took place primarily through the brazing alloy bulk, due to the high concentrations of Sn and Ti that caused the precipitation of abundant intermetallic compounds in the brazing alloy bulk. For Ag-based alloys having very low concentrations of Ti, no visible degradation of diamond was observed and the bonding strength was very high. Crack primarily propagated through the brazed interface or even the CVD diamond bulk.     

低Nb含量Ni-Ti-Nb形状记忆合金的组织及相变特征

系统研究了低Nb含量(原子分数为4．5％)的Ni-Ti-Nb形状记忆合金的微观组织形态和相变特征以及预变形对相变滞后的影响．结果表明，Ni／Ti比的微小变化对合金的微观组织产生重要影响，从而影响合金的相变特征．低Nb含量的Ni-Ti-Nb形状记忆合金仍然具有宽滞后效应．研究了在相同温度下分别处于马氏体和奥氏体状态时低Nb合金的变形行为，并结合热弹性马氏体相变动力学作了相关解释．     

Al-Li合金回归机制的计算机模拟

基于离散格点形式的微扩散方程(Langevin方程),对Al-Li合金在回归过程中δ-Al_3Li相溶解进行了原子层面计算机模拟,分析了析出相在回归过程中原子图像和序参数的演化,进而探讨了Al-Li合金的回归机制.首次探明Al-Li合金的回归过程有序相演化序列为化学计量比δ′相→非化学计量比有序相→无序基体,并论证了亚稳区合金的回归过程更趋向于失稳区合金时效过程的逆过程;失稳区合金的回归过程更趋向于亚稳区合金时效过程的逆过程.     

多主元合金中局部化学短程有序的研究进展

多主元合金因其独特的微观结构和优异的综合性能而展现出了广阔的应用前景,也是近年来金属结构材料领域的研究热点之一。作为一类新型复杂合金,多主元合金与传统合金在原子尺度上存在本质的区别,其中局部化学短程有序作为多主元合金中一种特殊的原子级微观组织,其与位错的交互作用将对合金的变形行为及力学性能产生重要的影响。本文综述了多主元复杂合金中局部化学短程有序的相关研究进展,主要包括化学短程有序的形成因素、表征方法以及对位错行为和力学性能的影响,并针对目前关于化学短程有序的定量表征、调控技术、理论模型建立及对服役性能的影响等方面存在的问题与不足进行了分析和展望。     

Local atomic structure of Zr–Cu and Zr–Cu–Al amorphous alloys investigated by EXAFS method

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

银基焊膏的研究进展

银具有高导电导热、耐腐蚀、抗氧化、延展性好等特性,制粉后添加不同合金元素与助焊剂以合适的比例混合制得的焊膏,在金属焊接与电子表面装联领域有着广泛的应用。结合近年来银基焊膏的最新研究进展,综述了银基焊膏中焊粉与助焊剂的研究现状,展望了银基焊膏的发展趋势。