Investigation on the Properties of CuCr Contact Material after Cryogenic Treatment

CuCr contact material has been widely used for vacuum interrupters in medium-voltage applications. The microstructure of CuCr contact material is the important factor to determine the properties of vacuum interrupter. In this work CuCr alloys fabricated by normal powder metallurgy are processed by the cryogenic treatment. The microstructure and properties of the contact materials after cryogenic treatment are investigated. Test results show that cryogenic treatment result in fine microstructure of the contact material, especially in Cr composition in CuCr alloy. During the cryogenic process, the low temperature caused the particles in the microstructure to rearrange, which made copper and chromium compositions better distributed. Fine microstructure and uniform distribution of alloys are beneficial to improving the properties of contact materials. The resistance to the arc erosion has been improved greatly by the cryogenic treatment.