环保型银基电触头材料的稀土元素微合金化及其界面改性机理研究

Ag/SnO2电触头材料是目前公认最有希望的环保型Ag/CdO替代材料。大量研究表明，Ag/SnO2界面结构和性能，是影响该材料性能稳定性的主要因素。本项目针对金属Ag基体与SnO2颗粒界面润湿性差的问题，重点考察几种微量稀土元素添加对Ag/SnO2触头材料的界面改性及其机理。具体开展以下研究：(1)采用高分辨透射电镜（HRTEM）等手段，表征对比微合金化前后金属银/氧化物的界面结构特征和晶体取向关系；(2)借助电子探针（EPMA）、三维光学轮廓仪（3DOP）、电弧侵蚀模拟实验和润湿性实验等手段，揭示微合金化对Ag/SnO2材料抗电弧侵蚀性和界面润湿性的影响机理； (3)综合界面结构表征和宏观性能测试结果，揭示稀土元素微合金化的界面改性机理。项目旨在建立材料界面微观结构与宏观性能间的相关性，发展基于界面效应的合金化设计新方法，为优化设计和制备该类材料提供重要的理论指导。

Ag/SnO2 electrical contact materials were recognized as the most promising and environment friendly alternative materials of Ag/CdO. A larger number of studies have indicated that the structure and property of Ag/SnO2 interface is the main influence factors of performance stability of Ag/SnO2 electrical contact materials. This project aimed at the interface problem of poor wettability between silver matrix and SnO2 particles, focuses on the interface modification effect and mechanism of several kinds of rare earth elements addition for Ag/SnO2 electrical contact materials. The research contents are as followings: (1) interface structure and crystal orientation of Ag/SnO2 electrical contact materials before and after micro-alloying of rare earth element, will be characterized and compared by HRTEM, EFTEM and EELS; (2) effect mechanism of rare earth element micro-alloying for the resistance of arc erosion and interface wettability of Ag/SnO2 electrical contact materials, will be investigated by the use of electron probe micro-analyzer (EPMA), three-dimensional optical profiler (3DOP), arc erosion testing and wettability experiment; (3) interface modification mechanism of rare earth elements micro-alloying will be revealed by the combination of interface structure characterization and macro-performance testing. The aims of this program are to establish the internal correlation between microstructure of interface and macro-performance of materials, develop a new method for alloying designing based on interface effect, and provide important theoretical guidance for the scientific design and preparation of this kind of metal matrix composites.