LaSrCuO4粉体微结构对Ag/LSCO电接触材料性能的影响

以硝酸镧、硝酸铜、硝酸锶等为原料,分别采用固相法、溶胶-凝胶法和共沉淀法合成了不规则颗粒状(LSCO_g)、介孔状(LSCOm)和片层状(LSCOl)的LaSrCuO_4(LSCO)粉体。采用高能球磨并结合初压-初烧-热压工艺制备出Ag/LSCO电接触材料。利用X射线衍射(XRD)、扫描电镜(SEM)、金属电导率仪、维氏硬度计和电寿命试验机等对粉体形貌及电接触材料的物理和电学性能进行了表征。结果表明:与Ag/LSCO_(m)、Ag/LSCO_l材料相比,Ag/LSCO_(g)电接触材料表现出更加优异的物理性能,其电阻率为2.37μΩ·cm,硬度为800MPa,密度为9.32g/cm~3;但电学性能差异较小,其在AC220V12A开断状态下的燃弧能量为400 mJ、燃弧时间为23 ms,关合状态下的燃弧能量为1500 mJ,燃弧时间为68ms。Ag/LSCO电接触材料的主要失效形式是液滴喷溅,微裂纹和孔洞。     

细晶W-25Cu-2.0 mass%La_2O_3合金电接触性能

采用包套热挤压法制备了稀土氧化镧掺杂W-25Cu-2.0 mass%La_2O_3合金,在JF04C型电接触试验机上测试了稀土掺杂钨铜合金的接触电阻、燃弧时间、燃弧能量等电接触性能,利用钨灯丝扫描电镜对电接触材料阴阳两极电弧侵蚀形貌进行了微观分析。结果表明:稀土钨铜合金触头材料接触电阻较纯钨铜合金明显减小,且接触电阻不随接触电压的增大而增大;燃弧能量和燃弧时间随着接触电压的增大而增大,且波动性变大;闭合过程中的燃弧能量和燃弧时间均大于断开过程。电弧侵蚀后材料转移方向为阳极向阴极转移;电弧侵蚀形貌为阳极表面出现微小凹坑、阴极表面产生微小凸起;阳极触头表面出现富W区,阴极触头表面出现富Cu区,La_2O_3主要聚集在富W区。     

Ag/纳米SnO_2电接触材料的制备及其电学性能

以化学Ag粉和纳米SnO_2为原料,用高能球磨法制备复合粉体并通过粉末冶金、热挤压、轧制等工艺获得Ag/SnO_2线材并对其进行退火处理。采用扫描电镜(SEM)和能谱仪、维氏硬度计、电桥以及电寿命试验机等对线材的电寿命测试前后的表面形貌、不同退火温度下的显微硬度和电学性能进行表征。结果表明,热挤压后,氧化物沿挤出方向呈条带状分布。随着退火温度从室温升高至920℃,线材电阻率由2.432μ?.cm降至2.202μ?.cm,HV维氏硬度由1.13GPa降至1.01GPa。920℃退火后,试验触头的燃弧时间、燃弧能量、接触电阻等较退火前明显升高,但表面形貌的变化以及熔焊力更小,烧蚀质量损失降低近60%,呈现出良好的抗电弧侵蚀能力。     

不同接触压力和电极间距下AgTiB_2触头的材料转移行为（英文）

为了阐明接触压力和电极间距对Ag基触头材料转移行为的影响,在阻性负载24V/16A条件下对Ag-4wt.%TiB_2触头材料在电接触测试系统中进行不同接触压力和电极间距5000次电弧侵蚀实验,系统研究燃弧能量和燃弧时间与接触压力和电极间距的关系,表征电弧侵蚀后阳极和阴极的表面形貌,测量电弧侵蚀后两电极的质量变化,并对材料转移行为进行讨论。研究结果表明:接触压力显著影响燃弧能量、燃弧时间和侵蚀形貌,但并不改变材料转移模式。然而,电极间距不但影响燃弧能量、燃弧时间和侵蚀形貌,而且改变材料转移方向。当电极间距为1 mm时,材料转移方向为由阳极到阴极;而电极间距为4 mm时,材料转移方向发生逆转,即材料由阴极向阳极转移。     

Ag-La_2Sn_2O_7/SnO_2电接触材料的抗电弧侵蚀特性研究（英文）

采用化学共沉淀法合成了La_2Sn_2O_7/SnO_2复合粉体,并通过粉末冶金法制备了Ag-La_2Sn_2O_7/SnO_2电接触材料;研究了复合材料的抗电弧侵蚀性能,并对抗电弧侵蚀机理进行了探讨。结果表明:与Ag-SnO_2相比,Ag-La_2Sn_2O_7/SnO_2电接触材料经电弧作用后表面形貌较为平整,表现出较低的熔焊力。这可能是由于在电弧作用下La_2Sn_2O_7的存在有助于提高熔池的粘滞性,同时Ag-La_2Sn_2O_7/SnO_2触点表面分布的"小汗珠"状颗粒物能够起到分散电弧能量的作用,从而可以降低侵蚀区域的温升、减弱表面结构的破坏程度,获得较好的抗熔焊性能。Ag-La_2Sn_2O_7/SnO_2有望作为一种环保型电接触材料得到广泛应用。     

直流条件下Cu-10Cr电接触材料燃弧侵蚀特性

采用放电等离子烧结方法制备Cu-10Cr电接触材料,利用JF04C触点材料测试系统对Cu-10Cr电接触材料进行恒流条件下的电接触燃弧试验。分析在直流阻性负载条件下Cu-10Cr电接触材料的转移损耗情况,观察其燃弧侵蚀微观形貌,探讨材料的燃弧机制。结果表明:直流电弧会引起材料表面的熔化和转移,电流高于35 A时触点材料发生从阴极向阳极的转移;电接触表面呈现有熔池、浆糊状、气孔、裂缝、菜花状等多种微观形貌特征;燃弧能量随燃弧时间的增加而增大,并且在该试验条件下燃弧能量E和燃弧时间t存在线性关系。     

新型AgZrB2 触头材料的制备及电气性能

采用超声、球磨和放电等离子烧结相结合的方法制备了不同ZrB₂含量（3%,5%,7%,质量分数）的新型AgZrB₂触头材料,并通过电接触试验研究了触头材料的电弧侵蚀和材料转移行为。结果表明,ZrB₂含量显著影响AgZrB₂触头材料的耐电弧侵蚀性能。Ag-3% ZrB₂触头材料具有稳定的闭合/分断燃弧能量和持续时间,表现出较好的耐电弧侵蚀性能。但是,过多的ZrB₂会导致更高的闭合燃弧能量和更长的闭合燃弧时间,并且分断燃弧能量和时间会产生较大的波动,电弧侵蚀较为严重,这说明过量的ZrB₂不利于提高触头材料的耐电弧侵蚀性能。此外,Ag-3% ZrB₂和Ag-5% ZrB₂触头材料具有相同的材料转移模式——从阳极向阴极转移,而Ag-7% ZrB₂触头材料则呈现出相反的转移模式——从阴极向阳极转移。     

Al2O3-Cu/25W10Mo4Cr复合材料的电接触行为

采用真空烧结和内氧化法制备了Al_2O_3-Cu/25W10Mo4Cr复合材料,研究了其硬度、导电率、密度等综合性能和电接触性能。利用JF04C电接触触点测试系统测试了复合材料的熔焊力、燃弧时间、质量转移等电接触性能参数;利用JMS-5610LV扫描电镜对电接触试验后复合材料的表面进行微观形貌分析。结果表明:电压为DC 25 V时,Al_2O_3-Cu/25W10Mo4Cr复合材料的燃弧时间、燃弧能量随负载电流的增大而增大;接触电阻随负载电流的增大而减小;电接触后触点材料表面有气孔、裂纹、凹坑等典型电弧侵蚀特征。     

不同SnO_2粒度制备的AgSnO_2触头材料电弧侵蚀行为（英文）

为了阐明SnO_2粒度大小对AgSnO_2触头材料电弧侵蚀行为的影响,采用粉末冶金法制备不同SnO_2粒度的Ag-4%SnO_2(质量分数)触头材料,对触头材料组织进行观察,并对其致密度、硬度和导电率进行测量。对Ag-4%SnO_2触头材料进行电弧侵蚀实验,确定燃弧时间和电弧侵蚀前后的质量变化,并对电弧侵蚀后触头材料表面的形貌和成分进行表征。结果表明:细小的SnO_2颗粒有助于提高Ag-4%SnO_2触头材料的致密度和硬度,但降低了其导电率。随着SnO_2粒度的减小,Ag-4%AgSnO_2触头材料的燃弧时间变短,质量损失降低,电弧侵蚀面积增大,蚀坑变浅且分散。     

锡酸锌纳米粉体的制备及其在电接触材料中的应用

以不同的锌源,锡源与沉淀剂为原料,采用化学共沉淀法成功合成了具有尖晶石结构的高纯度立方锡酸锌纳米粉体。采用机械合金化和粉末冶金技术制备Ag/Zn_2SnO_4电接触材料。探究了煅烧温度、锌源种类和沉淀剂类型等工艺参数对Zn_2SnO_4粉体的微观结构和Ag/Zn_2SnO_4电接触材料性能的影响规律。采用场发射扫描电子显微镜和X射线电子衍射仪表征锡酸锌粉体的形貌和物相,并测试Ag/Zn_2SnO_4电接触材料的电阻率,硬度与密度等物理性能。结果表明:以五水四氯化锡,氯化锌与碳酸钠为原料,于1000℃条件下煅烧3h合成的Zn_2SnO_4增强Ag基电接触材料可达到最佳电阻率2.31μΩ·cm,此时材料相应的密度和维氏硬度分别为9.51 g/cm3和656.3 MPa。相比于传统的Ag/SnO_2与Ag/ZnO电接触材料,Ag/Zn_2SnO_4电接触材料在电学性能和致密度上具有明显优势;由Ag/Zn_2SnO_4材料的断口组织分析可知,Ag相与Zn_2SnO_4增强相颗粒间结合良好。     

Effects of Oxide-Modified Spherical ZnO on Electrical Properties of Ag/ZnO Electrical Contact Material

Silver-zinc oxide (Ag/ZnO) electrical contact material is widely used as contacts of the medium duty switching devices. Effects of modified ZnO on properties of Ag/ZnO electrical contact material were investigated in this work. NiO and CuO were introduced to modify spherical ZnO by a chemical solution nano-coating method. Ag/ZnO contacts prepared using the modified spherical ZnO were produced by powder metallurgy (PM) method in a muffle furnace in temperature ranges from 750 to 900 °C. Results show that electrical conductivity, stability of relative density, and Vickers’ hardness of Ag/ZnO electrical contact material can be improved by the addition of NiO because of the formation of NiO solid solution Zn_0.2Ni_0.8O. The addition of CuO to Ag/ZnO electrical contact material makes arcing energy and mass loss lower. Since this is attractive for a longer service life, using NiO and CuO co-modified ZnO as a second phase may be a promising way to improve properties of Ag/ZnO electrical contact material. Hence, the presented results could also be useful for the design of a new Ag/ZnO electrical contact material.     

The oxidation of lead-free Sn alloys by electrochemical reduction analysis

The oxidation of pure tin and Sn-0.7Cu, Sn-3.5Ag, Sn-1Zn, and Sn-9Zn alloys at 150°C was investigated. Both the chemical nature and the amount of oxides were characterized using electrochemical reduction analysis by measuring the electrolytic reduction potential and total transferred electrical charges. X-ray photoelectron spectroscopy was also conducted to support the results of reduction analysis. The effect of copper, silver, and zinc addition on surface oxidation of tin alloys is reported. For tin, Sn-0.7Cu, and Sn-3.5Ag, SnO grew first and then the mixture of SnO and SnO₂ was found. SnO₂ grew predominantly during long-time aging. For zinc-containing tin alloys, both ZnO and SnO₂ were formed. Zinc promotes the formation of SnO₂. For more information, contact Sungil Cho, Korea Advanced Institute of Science and Technology, Department of Materials Science and Engineering, 373-1 Kusung-dong, Yusung-gu, Daejon 305-701, Republic of Korea; +82-17-394-1026; e-mail sicho@kaist.ac.kr.     

Plasma electrolytic oxidation preparation and characterization of SnO2 film

SnO₂ film is firstly prepared by plasma electrolytic oxidation technology in sodium stannate solution. The structure and photocatalytic property of the film are characterized by SEM, XRD and UV-Vis spectrophotometer. Rough and porous netlike film formed on the substrate. The XRD result showed the oxide was pure SnO₂. The absorption edge of the film was determined as 420 nm. Photocatalytic degradation of rhodamine indicated SnO₂ film was an effective photocatalyst.     

第二相粒度对AgSnO2 触头材料润湿性和电接触性能的影响

选用TiO₂作为触头材料的添加剂,采用粉末冶金法制备了6种不同第二相（SnO₂）粒度的AgSnO₂和AgSnO₂/TiO₂触头材料。研究了2种触头材料的润湿性和电接触性能。用座滴法测量了Ag与SnO₂之间的润湿角,并表征了材料的湿润性,使用JF04C电接触触头材料测试系统对材料电接触性能进行了测试,分析了不同第二相粒度的触头材料的润湿性和电接触性能的变化规律。结果表明,当第二相粒度为100~300 nm时,2种触头材料的性能均优于其它粒度的触头材料。     

La2O3含量对Al2O3/Cu基复合材料组织与性能的影响

以La₂O₃粉、Al粉、CuO粉为反应物原料、纯铜为基体,采用原位合成技术和近熔点铸造法制备颗粒增强Cu基复合材料,研究La₂O₃对Al-CuO体系制备的Cu基复合材料组织及性能的影响。结果表明：添加La₂O₃可获得纳米Al₂O₃颗粒,且弥散分布于Cu基体中,制备的材料组织更加细小、均匀,其材料的电导率及摩擦磨损性能明显提高。当添加0.6%wtLa₂O₃,复合材料的电导率达到90.2%IACS,磨损量达到最小,相比未添加La₂O₃,其导电率提高10.1%,磨损量减小36.6%。     

P-type transparent conducting SnO2:Zn film derived from thermal diffusion of Zn/SnO2/Zn multilayer thin films

Highly transparent, p-type conducting SnO₂:Zn thin films are prepared from the thermal diffusion of a sandwich structure of Zn/SnO₂/Zn multilayer thin films deposited on quartz glass substrate by direct current (DC) and radio frequency (RF) magnetron sputtering using Zn and SnO₂ targets. The deposited films were annealed at various temperatures for thermal diffusion. The effect of annealing temperature and time on the structural, electrical and optical performances of SnO₂:Zn films was studied. XRD results show that all p-type conducting films possessed polycrystalline SnO₂ with tetragonal rutile structure. Hall effect results indicate that the treatment at 400 °C for 6 h was the optimum annealing parameters for p-type SnO₂:Zn films which have relatively high hole concentration and low resistivity of 2.389 × 10¹⁷ cm^− 3 and 7.436 Ω cm, respectively. The average transmission of the p-type SnO₂:Zn films was above 80% in the visible light range.     

SnO2@TiO2核-壳纳米线的制备及其光催化性能研究

本文通过固-液-气(VLS)生长机制,利用化学气相沉积法(CVD)制备SnO₂纳米线。利用原子层沉积(ALD)以钛酸四异丙酯为前驱体在SnO₂纳米线表面沉积不同厚度的TiO₂壳层,形成SnO₂@TiO₂核-壳纳米线结构。通过中间Al₂O₃插层,分别制备出金红石和锐钛矿两种不同晶型的TiO₂,从而制备出两种不同复合结构的SnO₂@TiO₂核-壳纳米线。实验研究该复合结构中TiO₂的厚度与晶型对紫外光下光催化降解甲基橙溶液活性的影响。     

Transparent conductive Sb-doped SnO2/Ag multilayer films fabricated by magnetron sputtering for flexible electronics

The effects of an embedded silver layer and substrate temperature on the electrical and optical properties of Sb-doped SnO₂ (ATO)/silver (Ag) layered composite structures on polyethylene naphthalate substrates have been investigated. The highest conductivity of ATO/Ag multilayer films was obtained with a carrier concentration of 1.5 × 10²² cm^?3 and a resistivity of 2.4 × 10^?5 Ω cm at the optimum Ag layer thickness and substrate temperature. The photopic averaged transmittance and Haacke figure of merit are 81.7%, and 21.7 × 10^?3 Ω^?1, respectively. In addition, a conduction mechanism is proposed to elucidate the mobility variation with increased Ag thickness. We also describe the influence of substrate temperature on the structural, electrical and optical properties of the ATO/Ag multilayer films, and propose a mechanism for the changes in electrical and optical properties at different substrate temperatures.     

不同方法制备的AgSnO2TiB2 电接触材料的微观结构和电弧侵蚀行为

分别采用球磨法、可溶性淀粉模板法和滤纸模板法制备了AgSnO₂TiB₂复合粉末,并利用火花等离子体烧结技术（SPS）制备了块体材料。对Ag4%SnO₂4%TiB₂（质量分数）电接触材料的物理性能和电弧侵蚀特性进行了研究。结果表明,模板的空间限域效应有效地改善了增强相在基体中的均匀分散,提高了Ag4%SnO₂4%TiB₂接触材料的导电率和硬度。与球磨法相比,滤纸模板法和淀粉模板法制备的Ag4%SnO₂4%TiB₂复合材料的电导率分别增加了12.18倍和9.60倍, 显微硬度分别增加了17.10%和33.94%。滤纸模板更有利于SnO₂和TiB₂的均匀分散,减少集中电弧侵蚀和飞溅损失,因此具有更好的抗弧蚀性。     

不同碳质相增强银基复合材料的电接触行为

采用粉末冶金工艺制备碳质相质量分数为3%的不同碳质相(石墨、碳纳米管和石墨烯)增强银基复合材料,并对其微观组织和物理性能进行表征。对复合材料触头进行直流阻性负载条件下的电弧侵蚀试验,研究了不同碳质相对复合材料电弧特征、材料转移和质量净损耗的影响。结果表明,银-碳纳米管复合材料具有最佳的致密度、硬度和抗拉强度;而银-石墨烯复合材料具有最好的导电率。复合材料触头的材料转移方式均为阴极向阳极转移。同等电接触参数条件下,银-石墨烯复合材料具有最佳电接触性能,其燃弧时间最短、燃弧能量最低、材料转移量和质量净损耗最少。