银基电接触材料改性及制备工艺

概述了银基电接触材料的发展,介绍了Ag-Ni、Ag-c、Ag-wc和Ag-MO4个主要系列的银基电接触材料的特点及其改性方法,比较了不同银基电接触材料改性前后的优缺点.同时,叙述了粉末冶金法、合金内氧化法及预氧化合粉末法等银基电接触材料的制备工艺.最后指出,提高银基电接触材料的性能、发展新型的节银触头材料和复合触头材料是今后银基电接触材料的发展方向.     

银基电接触材料的应用研究及制备工艺

鉴于银基电接触材料在电力系统、电器工业中的重要性,综合近年多种文献资料,阐述了Ag/Ni、Ag/C、Ag/WC和Ag/MeO等4个主要系列的银基电接触材料的特点.分析了喷射沉积法、溶胶-凝胶法、纤维强化法、等静压制法、等离子体喷涂法等制备银基电接触材料的工艺特点.结合现阶段研究工作,研制和改进电接触材料的制备工艺,发展新型环保触头材料、多相复合触头材料及纳米触头材料是今后银基电接触材料发展的主要方向.     

贵金属基电接触材料的研究进展

介绍了贵金属基电接触材料的种类、特点及应用范围,分析了国内外贵金属基电接触材料的使用条件及各种制备技术的优缺点。重点介绍了发展前景较好的4个系列银基电接触材料的各项性能指标、工作原理及应用方向,最后道出了电接触材料先进制备技术的研发方向,并指出了贵金属基电接触材料具有向多元化发展的趋势。     

La掺杂AgSnO2触头材料的电性能

由于Cd有毒性,AgSnO2触头材料逐渐取代了 AgCdO 成为新型触头材料,但由于AgSnO2触头材料中的SnO2近乎绝缘,使得触头材料的接触电阻增大,故改善SnO2的导电性是急需解决的重大难题.本文提出了一种简单的、低成本的La掺杂AgSnO2触头材料的设计方法.采用模拟计算的方法,利用第一性原理的密度泛函理论平面波超软赝势法,建立了SnO2以及不同比例La掺杂的SnO2超晶胞模型,在对其进行几何优化之后分别研究了 La掺杂比为50%、25%、16. 67%、12. 5%、8.34% 的SnO2材料的电子结构,并研究了其晶格参数、能带结构和态密度等.结果表明,掺杂后材料晶胞体积变大. La的5d轨道进入导带,使得导带底向低能端移动,禁带宽度变小.最终得出La掺杂比为16.67% 时导电性最佳.最后进行了不同掺杂比下触头材料的电接触性能试验,得到了接触电阻和燃弧能量等电接触性能参数并验证了模拟结果.因此,本文的研究为触头材料的发展和应用提供了理论依据.     

La掺杂AgSnO_2触头材料的电性能（英文）

由于Cd有毒性,AgSnO_2触头材料逐渐取代了AgCdO成为新型触头材料,但由于AgSnO_2触头材料中的SnO_2近乎绝缘,使得触头材料的接触电阻增大,故改善SnO_2的导电性是急需解决的重大难题。本文提出了一种简单的、低成本的La掺杂AgSnO_2触头材料的设计方法。采用模拟计算的方法,利用第一性原理的密度泛函理论平面波超软赝势法,建立了SnO_2以及不同比例La掺杂的SnO_2超晶胞模型,在对其进行几何优化之后分别研究了La掺杂比为50%、25%、16.67%、12.5%、8.34%的SnO_2材料的电子结构,并研究了其晶格参数、能带结构和态密度等。结果表明,掺杂后材料晶胞体积变大。La的5d轨道进入导带,使得导带底向低能端移动,禁带宽度变小。最终得出La掺杂比为16.67%时导电性最佳。最后进行了不同掺杂比下触头材料的电接触性能试验,得到了接触电阻和燃弧能量等电接触性能参数并验证了模拟结果。因此,本文的研究为触头材料的发展和应用提供了理论依据。     

Ag基触头材料的研究现状与展望

触头材料是开关系统的关键,其性能决定了电器设备运行的可靠性。低压开关中的触头材料以Ag基为主,Ag/CdO综合性能优异,但是Cd的毒性限制了它的应用。近几十年来,Ag/SnO_2、Ag/ZnO、Ag/Ni、Ag/C、Ag/W等触头材料在部分领域替代了Ag/CdO,但是这些替代材料的温升高、接触电阻大、抗材料转移性能差、抗熔焊性能差等问题无法得到有效解决。从触头材料的发展历史出发,围绕应用、制备、性能及研究现状等,介绍了低压开关中常用Ag基触头材料的研究概况,探讨了Ag基触头材料的发展动向,并介绍了MAX作为增强相在Ag基触头材料中应用的前景。     

低压继电器用AgSnO2触头材料的研究进展

简述了低压继电器用触头材料的工作状态、性能要求和AgSnO2材料的典型制备工艺.通过分析电弧侵蚀作用后的触头表面组织结构及其对电性能的影响,提出了降低接触电阻、增强界面结合强度和分散电弧的主要改善手段,并展望了AgSnO2材料的发展趋势.     

汽车继电器用AgMeO触点材料不同配对方式时的性能

为了探究触点配对方式对汽车继电器电接触性能的影响,选取AgMeO型触头材料进行实验,采用粉末冶金法制备AgSnO₂, AgCuO和AgZnO 3种触头材料,并测量其物理性能,采用JF04C电接触触点材料测试系统,按5种不同触点配对方式进行电接触实验,并对实验前后的阴阳极触点进行称量,实验结果表明：触点配对方式对接触电阻,材料转移和损耗影响较大,对燃弧能量的影响较小,通过对触点进行不对称配对可以明显降低接触电阻和材料转移和损耗,明显改善汽车继电器的接触性能.     

不同触头压力下真空灭弧室温升分布研究

开关设备作为线路的供电单元,各部分的温度不得超过允许值,作为真空开关及断路器的核心元件,真空灭弧室的温升性能主要取决于回路电阻大小。真空灭弧室的回路电阻主要由动静触头本身电阻值及接触电阻值组成。断路器合闸时,灭弧室动静触头接触,但表面仍然会存在间隙,间隙面以金属桥的形式导电形成接触电阻。不同的触头压力及接触面粗糙度不同时,动静触头的间隙也不同,从而影响真空灭弧室的回路电阻及其性能。本文通过对灭弧室不同触头压力及接触面不同粗糙度时灭弧室动静导电杆温升的研究,分析触头压力及触头接触面粗糙度对灭弧室温升的影响,得到不同触头压力及触头表面粗糙度下温升变化趋势,为真空灭弧室设计中触头材料及表面粗糙度的选择、形状的设计提供理论基础。     

新型石墨烯增强铜基复合电触头材料研发进展

正一、电触头材料触头材料在断路器中的功能是在电路中接通和断开电流。对高压断路器而言,理想的触头材料必须具有良好的导电、导热性及耐电弧烧损、抗熔焊、小的电磨损、低而稳定的接触电阻、不与使用介质起化学变化、有一定的强度和易于机械加工等特性。早期的触头材料多采用纯钨     

稀土在银基接触材料中的作用与应用

介绍了稀土在银及银合金电接触材料中的作用、特点及影响效果,阐述了国内外稀土银合金电接触材料的应用情况,展望了稀土银合金的发展前景。     

新型AgSnO2触头材料的制备和电弧侵蚀特性

用高能球磨技术和热压烧结方法制备出新型AgSnO2触头，XRD、光学显微镜和TEM分析表明，在该合金的微观组织中纳米Sn02弥散分布于Ag晶粒内，与常规AgSn02 In2O2触头相比，AgSn02触头的表面没有明显的液体喷溅和燃弧裂纹，呈现出比较好的耐电弧侵蚀特性．     

The segregation of silver nanoparticles in low-cost ceramic water filters

As an impregnated constituent in low-cost ceramic water filters, silver nanoparticles have a demonstrated antibacterial effect. The bactericidal mechanism is believed to be based on direct contact between silver and the cell wall of a contaminant organism. In this study microstructural analysis was used to examine the effect of the processing method on the distribution of silver nanoparticles in the filter material. Silver nanofluid was impregnated into fired clay ceramic samples by a low-cost soak-and-dry method. Analyses of filter samples by scanning electron microscopy, energy dispersive spectroscopy, and digital optical topological mapping showed that silver was concentrated in near surface pores, a condition that is not optimal for highest probability of silver contact. A simple experiment showed that segregation of silver occurs during the drying phase of impregnation. Drying curves showed that 90% of contained liquid evaporates from the external surface.     

Untersuchung des Erosionsverhaltens von silberbasierten Kontaktwerkstoffen mittels FIB‐Techniken

Microstructure investigations and arc erosion behaviour of silver‐based contact materials by focused ion beam technique The understanding of the degradation mechanisms of contact materials is a key issue for the development of new materials with enhanced durability. This can be achieved through the investigation of the microstructure modification caused by electrical arcs on the surface of contacts. In this work, the erosion behaviour of pure silver and silver based composites as well as the characterization in two or three dimensions is presented. Single breaking operations were performed with direct current. Using white light interferometry, the size of the craters on the surface as well as the volume of eroded material has been measured. By means of dual beam techniques, the microstructural modifications in the crater have been investigated and reconstructed in three dimensions.     

Industrial Radiology,Past, Present and Future

A new model for sulphur sensitization has been developed. It is based on the surface double layer which has previously been shown to occur in silver halides. The charge present in this double layer causes the energy bands to bend downward or upward according to whether silver sulphide is present on the crystal surface or not. Where silver sulphide is not in contact with the surface the bands bend upward, thus impeding the motion of photo-electrons towards the surface. Conversely in points where silver sulphide is adsorbed onto the Srystal surface, the bands bend downwards, thus yielding an attracting force driving the photoelectron towards the silver sulphide speck. The bending of the bands may have the additional effect of increasing the lifetime of electrons in traps which are near to a silver sulphide Speck, thus holding the trapped electron for a long enough time as to allow the “ionic step” to take place. Our experimental results as well as others reported in the literature are explained with this model.     

A robust low cost thick film system for the consumer market

This paper describes the fabrication and test of a new low cost thick film system using base metals. The resistor pastes were developed using non-precious metal oxides and contain molybdenum trioxide and other additives. The conductors are either silver or nickel. The dielectrics contain barium oxide, but, unlike ruthenium based resistors, on related dielectrics, there is very little difference in resistor behavior on alumina from that on the dielectrics investigated. Long term stability tests show that the new resistor family, while less stable than those based on ruthenium, is suitable for many low cost applications. Results suggest that high temperature ageing tends to minimize contact effects and that they are compatible with both silver and nickel terminations.     

Improved contacting by the use of silver in solid oxide fuel cells up to an operating temperature of 800 °C

In the following, a contacting variant for solid oxide fuel cells will be presented in which the conductivity of the interconnect is ensured by contact elements made of fine silver. To this end, the interconnect has holes through which the contact elements of fine silver (99.9 wt% Ag) are introduced and then pressed. This pressing process and the thermal expansion of the silver during heating leads to a gastight joint. The silver penetrations are additionally soldered to render them capable of withstanding temperature cycling. Contact resistance measurements and corrosion studies at 800 °C in air or Ar/4 vol.% H₂/3 vol.% H₂O demonstrate the functionality of the contacting variant under the described conditions. The experimental results indicate that contacting by means of silver contact elements ensures long-term stability up to operating temperatures of 800 °C. Current transmission via the silver contact elements means that a large number of materials are conceivable as the interconnect material. In the following application, an FeCrAl steel (1.4767, Aluchrom Y Hf—trade name Krupp Thyssen Nirosta) with 5.7 wt.% aluminium was used. At the operating temperature, a dense aluminium oxide layer forms on its surface which prevents the vaporization, for example of chromium oxide species, during fuel cell operation.     

Kontaktwerkstoffe auf Silberbasis ‐ Gefüge und mechanische Eigenschaften

Silver‐based contact materials – microstructure and mechanical properties Different silver‐based materials have been used in relays and contactors. Silver‐based composite materials in particular have played an important role. To produce such composite materials on an industrial scale, conventional powder mixing and wet‐chemical methods are used. By means of the powder‐metallurgical route, these materials are processed in a second step into wire material. To produce silver‐based composite materials with a comparable microstructure, the usability of alternative production routes was tested. This article shows the potential of the methods high‐energy ball milling (HEM) and intensive mixing compared to the two above‐named conventional methods. The main focus is on the evaluation of the microstructure of the composite powder and the extrusion wires concerning the dispersion of the reinforcement component and the resulting mechanical properties of the wire material.     

Investigation of contact resistance between silicon and silver paste made by screen-printing

In this paper, the front contact resistance of screen-printing crystalline silicon solar cells was investigated. By establishing a fine model for silicon and silver paste contact made by screen-printing and fire-through, the three kinds of conduction mechanism were analyzed quantitatively. According to the model, the comprehensive calculation of the contact resistance between silicon and silver paste sintering was made for the first time. The results calculated in this study suggest that the contact resistance of silicon and silver paste is about 1.20 mΩ for 125 mm × 125 mm single crystalline silicon solar cells, this approximately agrees with the measured values. By optimizing composition of silver paste according to our results, the silver consumption per watt can be reduced, and the efficiency of crystalline silicon solar cells can be further improved. The results laid the foundation for studying the screen-printed crystalline silicon solar cell front contact metallization system.     

短碳纤维／银基复合材料的研制及性能研究

本文研究了用粉末冶金法制备短切碳纤维／银基复合材料，对复合材料进行了物理、机械性能测试并应用于电触点进行了电寿命试验。结果表明，不同的制造工艺对复合材料的性能影响很大。通过对碳纤维表面预处理、造反正确的制造工艺可以制得性能优于银／石墨系列的短碳纤维／银基复合材料。