CuCr25W1Ni2 contact material of vacuum interrupter
(State Key Laboratory for Mechanicals Behavior of Materials, School of Materials Science and Enginerring,
Xi′an Jiaotong University, Xi′an 710049, P.R.China)
Xi′an Jiaotong University, Xi′an 710049, P.R.China)
Abstract: CuCr25W1Ni2 alloy was prepared by means of vacuum induction melting (VIM). A series of Cu/Cr alloys with different compositions (mass fraction, 25%～75%) and Cr grain sizes (up to 150 μm) were investigated for their differences in physical properties and breakdown voltage. The influence of alloy elements and microstructure on the performance of CuCr25W1Ni2 alloy was also discussed. Experimental results show that the chromium phase is strengthened and its size is minimized by the addition of tungsten powder. After electrical breakdown, very fine tungsten particles in the melt layer form the external nuclei in the solidification process. The microstructure of surface melt layer of CuCr25W1Ni2 alloy is much flatter. It can notably improve the dielectric strength. On the other hand, the nickel can enhance the mutual solubility of copper and chromium, and the whole alloy is strengthened.
Key words: CuCr contact material; vacuum induction melting; dielectric strength