微晶CuCr材料的制备及电击穿性能的研究

The Investigation of the Micro Grain CuCr Alloys and Its Electrical Breakdown Properties

根据真空断路器大功率、小型化发展趋势对触头材料的要求，探索用高能球磨制粉、热压烧结的方法制备微晶ＣｕＣｒ触头材料．结果表明，高能球磨能够制备出超细晶Ｃｕ－Ｃｒ合金粉．７５０℃热压时材料仍保持合金粉形貌，颗粒内发生部分过饱和固溶Ｃｕ与Ｃｒ的时效析出过程．９２０℃热压时Ｃｕ与Ｃｒ组元重新分布并发生了再结晶过程，晶粒尺寸为２～３μｍ，远远小于常规方法生产的ＣｕＣｒ材料．由于微晶ＣｕＣｒ材料中Ｃｒ相固溶度升高，使材料电击穿机制发生变化，首次击穿相从常规材料中的Ｃｒ相转移到Ｃｕ相上．

The contact materials have to be developed for the requirement of vacuum interrupters which tend to be high power and compact. CuCr alloys prepared by high energy ball milling and hot press were investigated in this paper. The experiment results show that the ultra fine Cu Cr alloy powders can be got by high energy ball milling. The alloy remained the powder morphology when hot press was taken at 750℃, but the saturated Cu phase and Cr phase precipitated partly; The element Cu and Cr would redistribute and the recrystallization took place when hot press at 920℃; The grain size of these alloys is 2～3μm, much smaller than that of general CuCr contact materials. The breakdown mechanism changed for the excess solubility of Cr phases, the first breakdown took place on Cu phases.