Preparation and Performance of Cu-Cr Contact Materials for Vacuum Switches with Low Contact Pressure

Insufficient anti-welding properties limit the application of Cu-Cr contact material in vacuum switches with low contact pressure. The CuCr-W-C alloys that are prepared are for decreasing welding tendencies and keeping the voltage withstand by addition of W and C elements. It is found that the average welding force of CuCr-W-C alloys is reduced more than 50% compared with that of the Cu 50 Cr 50 alloy. Especially for CuCrW 3.0 C 0.3 and CuCrW 1.0 C 0.5 , the welding forces reduce to only 10% of Cu 50 Cr 50 . Arc erosion areas of CuCr-W-C alloys are enlarged by five times more than that of the Cu 50 Cr 50 alloy in the same arcing conditions. The results of type tests were qualified. The results suggested that the CuCrW 2.0 C 1.0 alloy could be used in vacuum switches with low contact pressure to replace the W-Cu type contacts.