Processing and Characterization of Cr-Cu Alloys through Liquid Phase Sintering for Vacuum Circuit Breakers

Powder metallurgical processing of Cr-Cu has advantages over other processes.Vacuum Cirbuit Breakers are well known as vacuum interrupters (VI).The essential properties required for materials used in VI are high electrical conductivity, good skeleton strength and spark erosion resistance.The effect of sintering temperature, compaction pressure and composition on microstructure, sintered density, mechanical properties (tensile strength, hardness) electrical conductivity and skeleton strength of Cu-Cr contacts was investigated.The effect of microstructure on net-shape consolidation and macrostructure evolution during sintering are also detailed.Liquid phase sintering of Cr-Cu alloys resulted in better density without any significant shape distortion.Tensile strength increased with compaction pressure and chromium content.Higher compaction pressure also led to increased bulk hardness.Electrical conductivity increased with increasing compaction pressure and Cu content.