反应合成AgSnO2电接触材料的电接触性能研究

抗电侵蚀性能是衡量电接触材料品质的一个重要指标。对采用反应合成技术制备所得的银氧化锡电接触材料进行电接触试验,研究在直流、阻性负载条件下AgSnO2（10%,质量分数）的电接触性能。结果表明,反应合成法制备的AgSnO2（10%,质量分数）电接触材料在一定电流值范围内抗电侵蚀效果、抗熔焊能力好。在触点分断操作过程中电弧对材料的侵蚀效果要比闭合操作过程的侵蚀效果显著。     

加压内氧化法制备银金属氧化物复合材料的电接触行为

采用相同工艺条件的加压内氧化法制备出3种不同组分的Ag-SnO2,Ag-CdO及Ag-CuO复合材料.研究了不同金属氧化物种类对复合材料电接触行为和性能的影响,并分析了复合材料的显微组织、导电率、显微硬度、侵蚀量、温升和电弧侵蚀表面情况.结果表明:与Ag-CdO和Ag-CuO材料相比,在220 V/10 A电接触条件下,Ag-SnO2材料表现出更好的耐电弧侵蚀性能和更低的温升.金属氧化物的种类显著影响复合材料的组织均匀性、导电率、温升和侵蚀量.Ag-SnO2和Ag-CdO材料的电弧侵蚀表面光滑、均匀,而Ag-CuO材料表面坑洼、粗糙.     

Ag/SnO2电接触材料的制备及烧结条件对密度的影响

以AgNO3和Sn(Ⅳ)盐为原料,采用水热还原法合成了银氧化锡(Ag/SnO2)复合粉体.复合粉体经压片、烧结制得片状Ag/SnO2电接触材料.通过XRD和SEM等手段对制得的Ag/SnO2复合粉体进行表征,系统考察了烧结时间、烧结温度、SnO2含量等因素对Ag/SnO2电接触材料密度的影响.结果表明,所得Ag/SnO2粉体为高度分散的球形颗粒; Ag/SnO2粉体经压片后,于750℃烧结3h所得电接触材料的密度最大;且材料的相对密度随其中SnO2含量的增加而略有降低,当SnO2含量在8%～16%(质量分数)之间时,所得Ag/SnO2电接触材料的相对密度均达到了97%以上.     

稀土贵金属电接触材料的进展

本文介绍了稀土在贵金属触点材料中的作用、特点及影响效果，并阐述了国内稀土贵金属电接触材料的应用情况。     

新型铜基电接触材料的高温氧化性能研究

研究了铸态和热处理态新型铜基电接触材料的高温氧化行为,并用SEM观察了表面氧化膜的微观形貌。结果表明,与铸态材料相比,热处理态铜基电接触材料表面氧化膜的致密性和连续性较高,氧化增重较低,表现出更好的高温氧化性能。     

新型Ag-CNTs电接触材料的制备及其性能研究

采用化学沉积包覆和粉末冶金法,研制了一种新型的Ag-CNTs电接触材料.利用电子万能试验机、触点材料测试系统、扫描电镜等分析手段,分析了材料的微观组织和性能.结果表明:新材料具有优异的烧结致密度、电性能和加工性能,热挤压后密度可达理论密度的99.6%、电阻率仅为1.91 μΩ·cm,优于相同工艺制备的Ag-Ni、Ag-SnO₂传统电接触材料.经电弧侵蚀对比试验发现,同等条件下新材料电弧侵蚀量最小,且电寿命为上述2种传统材料的2倍.该材料有望成为一种可替代Ag-Ni、Ag-SnO₂的新型电接触材料.      

制备工艺对AgSnO_2(8)In_2O_3(4)电接触材料组织与性能的影响

分别采用粉末冶金法、合金粉末预氧化法和加压内氧化法制备AgSnO2(8)In2O3(4)电接触材料,研究不同制备工艺对AgSnO2In2O3电接触材料微观组织与性能的影响。结果表明:加压内氧化法制备的AgSnO2In2O3材料的组织均匀性最佳,致密度最高,显微硬度最大;粉末冶金法制备的AgSnO2In2O3材料导电率最好;直流阻性负载条件下,加压内氧化法制备的AgSnO2In2O3材料的耐电弧侵蚀性能最佳,其触点的失重最少,触点表面侵蚀区域面积最小。     

银基锡氧化物增强电接触材料的界面结合因子分析

利用固体与分子经验电子理论EET和改进的TFD理论对银基锡氧化物增强电接触材料中存在的和可能存在的晶体结构进行价电子结构及部分晶面的电子密度计算，得到各异相界面结合因子，并且对可能存在的最佳界面结合方式进行预测，从而对常用的两种改善银基锡氧化物增强电接触材料的方法，即：第三相元素的添加和制备工艺的改善提出价电子结构方面的解释。     

铜银合金接触线(CTHA)的性能研究

利用φ19mm铜银合金杆经冷拉成型为CTHA120(横截面为120mm2电气化铁路用接触线)合金接触线,并进行了室温及高温性能测试,同时对19mm铜银合金杆及CTHA120的样品纵、横截面进行金相组织及力学性能分析,发现经过冷拉成型的接触线,具有较高的抗拉强度,可以满足接触线性能的要求。     

铜基预合金粉末制备金刚石锯片的性能研究

采用共沉淀法制备了不同铜铁配比（质量比:45:35、50:30、55:25）的铜基预合金粉末,利用真空热压法烧结得到含金刚石的铜基结合剂刀头,通过激光焊接的方法制备出铜基结合剂金刚石锯片,研究了铜基预合金粉末中铜铁含量（质量分数）对金刚石锯片性能的影响。利用扫描电子显微镜观察锯片断面的显微组织形貌,并测量不同铜铁含量锯片的硬度和磨损量。结果表明:在三种配比中,当铜和铁质量比为50:30时,铜基结合剂与金刚石间的结合最佳,锯片性能最好,硬度最高（HRB 118）,锯片的磨损量最少（1.16 g）。     

Microstructure and Electrical Properties of Er_2O_3-Doped ZnO-Based Varistor Ceramics Prepared by High-Energy Ball Milling

Zinc oxide (ZnO) varistors exhibit highly nonlin-ear voltage-current (V-I) properties and it is ex-pressed bythe relationI=KVα,whereKis a constantandαis a nonlinear coefficient .They are extensivelyused as surge arresters in electric power lines ,such a…     

Effects of Rare-Earth La2O3 Addition on Microstructures and Electrical Properties of SrTiO3 Varistor-Capacitor Dual Functional Ceramics

Generally, metal oxide varistors used for the pro tection of electrical circuits are based on ZnO andTiO2[1,2]. ZnO varistor, which is widely used due toits high non linearity coefficient, is composed of ZnOceramics with minor oxide additive…     

A Study on La2O3－Y2O3－Mo Secondary Emission Material

The substrate molybdenum doped with La2O3, Y2O3 cathode material was made by the powder metallurgy method. The secondary emission coefficients of the materials were tested. The experimental results show that Mo cathodes doped with La2O3, Y2O3 have good secondary emission properties. When the cathodes are activated, the maximal secondary emission coefficients of these cathodes are higher than 2.0 and can meet the practical requirement. The distribution of the rare earth in the interior and at surface of this kind of cathode material before and after emission was studied using Scanning Electronic Microscopic (SEM) and X-Ray Photoelectron Spectrum(XPS). The analysis results show that the rare earth is easy to gather at grain boundaries and the relevant concentration of rare earth on the surface after emission is obviously greater than that before emission.     

Microstructure and Electrical Properties of Er2O3-Doped ZnO-Based Varistor Ceramics Prepared by High-Energy Ball Milling

The microstructure, electrical properties and density of ZnO-based varistor ceramics with different Er2O3 content prepared by high-energy ball milling （HEBM） and sintered at 800℃ were investigated. With increasing Er2O3 content, the ZnO grain size decreases due to the Er-rich phases inhibiting grain growth ; and nonlinear coefficient （ α ） decreases because of the decrease of barrier height （φB） The breakdown voltage （Eb） and density increase, whereas leakage current （IL） decreases with increasing Er2O3 content. The barrier height （φB）, donor concentration （Nd）, density of interface states （Ns） decrease and barrier width （ω） increases with increasing Er2O3 content due to acceptor effect of Er2O3 in varistor ceramics.     

Oxidation Resistance of Fe-13Cr Alloy with Micro-Laminated （ZrO2-Y2O3 ） / （Al2O3-Y2O3 ） Films

Oxidationofmetalsoralloysathightemperatures canbetreatedasaspecialcaseofmetalliccorrosion,inwhichsolidphasesinteracteitherwithaliquid agentoragaseousagent.Toimprovetheresistance againsthigh temperatureoxidationandelectrochemical corrosionofmetals,thesurfa…     

Al2O3-Y2O3 Nano- and Micro-Composite Coatings on Fe-9Cr-Mo Alloy

Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.     

Electrical Properties and Applications of （ZrO2）0.92 （Y2O3）0.08 Electrolyte Thin Wall Tubes Prepared by Improved Slip Casting Method

8%(mole fraction) yttria-stabilized zirconia electrolyte thin wall tubes were prepared by improved slip casting method. The length and wall thickness of the tubes are 266 mm and 0.4 - 0.9 mm, respectively and the relative density is 96.7 %. The microstructure and electrical properties of samples sintered at different temperatures were studied using SEM and ac impedance spectroscopy. The effect of sintered density, grain and grain boundary on the electrical properties of the samples was analyzed. The research results show that the density of the samples increases gradually with increasing sintering temperatures. The microstructurc of samples strongly influences its electrical properties, and the electrical prop.erties of samples enhance with the increase of sintered density. The ionic conductivity of grain and grain boundary is increased as the sintering temperature increases. Better sinterability of the samples was obtained at the sintering temperature of 1650℃. The maximum open circuit voltage and short circuit current for single cell is 0.946V and 1.84A, respectively. The maximum output power of single cell is 0.46W at the temperature of 850℃.     

纳米技术在电触头材料中的应用

自80年代纳米技术在材料领域通过纳米粒子以及各种超微细的结构模块，导致产生出许多新的具有优异性能和新的应用可能的纳米复合材料。纳米材料由于组成晶粒超细，大量原子位于晶界上，因而在机械性能、物理性能和化学性能等方面都优于普通的粗晶材料。最近几年这一技术在电触头材料的研究和制备过程中已经有了初步的应用，并取得了良好的效果。综述了近几年来纳米技术在电触头材料中的应用概况，介绍了已经制备出并见于报道的和正在研究的纳米晶触头材料的具体制备工艺及其性能的改善情况，展望了纳米技术在该类材料中的应用前景。