纳米复合银基电触头材料的研究

Study of Nanocomposite Silver-Based Contact Materials

利用高能球磨技术及热压烧结工艺制备出第二相弥散均匀分布于 Ag 基体中的纳米复合 AgNi 和 AgSnO2 触头,对复合粉末和合金触头进行了 X 射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)分析。结果发现:经长时间高能球磨后,复合粉末的晶粒明显细化,第二相粒子尺寸已达到 40 nm 左右,并在球磨过程中通过嵌入、焊合弥散分布于Ag 基体中,消除了传统方法第二相聚集及在晶界处的连续析出等缺陷。在退火、热压过程中第二相并未明显长大,仍保持在 50 nm 左右。对触头进行 SEM 观察时发现,2 种触头的晶界处都保持着有利于电性能的 Ag 膜。与常规商用触头相比,纳米复合触头有分散电弧作用,表面没有明显的熔池和液体喷溅,呈现出较好的耐电弧侵蚀特性。

The preparation method and arc erosion characteristics of the AgNi and AgSnO2 contacts materials which was fabricated by high-energy ball milling, hot pressing and sintering were studed. The powder morphology and microstructure of contact were analyzed by X-ray Diffraction (XRD), Scan Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The results shows that the grain size of composite powder has been fined, that the particle size of second phase was about 40 nm after high energy ball milling and the particles are dispersed in the Ag matrix in inlaying and welding, in witch the second phase aggregatin in the matrix and deposition on the grain bourdary that was caused by orthodox method has been abated. After hot pressing and annealing, there was not obviously growth of second phase and the particle size was about 50 nm. It was also found that the Ag film distributed on the grain boundary was retained in both contacts, which was propitious to the improvement of conductance capability. Compared with the commercial contacts, there was not obviously melting pool and splash of fused mass on the nanocomposite contact surface, which indicated that the arc on the contact surface was dispersed and the material was possessed of less are erosion in the arcing process.