Research On The Preparation And Properties Of NaNo-Ag/SnO₂Electrical Contact Materials

Ag/SnO2contact materials have extensive application prospect in the field of electricalcontact materials because of good wear resistance, electrical and thermal conductivity, andmany other advantages. However, if the Ag/SnO2contact materials under the workingcondition of AC3, the contact resistance and temperature rise of them are high and result inthe decrease of electrical endurance. In addition, the plasticity and ductility of the Ag/SnO2contact materials are poor because of the large particle size and hardness of SnO2particles.Therefore, the machining and forming of the Ag/SnO2contact materials become verydifficult. In this paper, according to the performance requirements of AC contactor andthe key problems of Ag/SnO2contact materials, a new kind of nano-Ag/SnO2contactmaterials were designed. The matrix is Ag, the wild phase is SnO2, the additive are La2O3,Ce2O3,TiO2and so on. The new nano-Ag/SnO2contact materials improved the processingand electrical performance.Nano-SnO2composite powders with additive content were prepared by sol-gel technique.The influence of technical parameter, which include reactive concentration, ratio of solvent,PH value, reaction temperature, calcination emperature and time on the performance andmicrostructure of composite powders was analyzed.Nano-Ag/SnO2contact materials adding metal oxide were prepared by powdermetallurgy technology.The optimized PM technical parameters were acquired by analyzingthe influence of forming process and sintering process. Nano-Ag/SnO2contact materialsadding metal oxide were prepared under the optimized PM technical parameters. Thephysical and mechanical properties, microstructure, temperature rise, connecting andbreaking capability and electric parameters which influence the life of the contact terminalwere tested and analyzed.The influence of rare earth oxides on the crystal structure of SnO2and compositematerial microstructure and electrical properties were analyzed by electrical contactperformance test and microstructure analysis methods. The arc erosion mechanism ofAg/SnO2contact was also discussed.