Arc erosion behaviors of CuW70 electrical contact materials adding LaB6

CuW70 alloys with different contents of LaB6 addition were prepared by powder metallurgy and infiltrating method, and the effects of LaB6 content on microstructure, densification, hardness, electrical conductivity and electrical breakdown properties were investigated. The results show that with increase of LaB6 addition, the hardness increases sharply and then decreases slowly, the CuW70 alloy with 2%LaB6 (mass fraction) has the maximum hardness value of 212 HB, while the electrical conductivity increases and then decreases slightly. The vacuum electrical breakdown experimental results show that, with the increase of LaB6 addition, the breakdown strength increases sharply and then decreases when the LaB6 content is above 2%. The chopping current decreases and then increases slowly, whereas, the arc life presents an increasing trend. In the range of the experiments, CuW70 alloy with 2% LaB6 has an optimal arc erosion resistance, and the breakdown strength, chopping current and arc life are 1.25×108 V/m, 2.62 A and 15.67 ms, respectively. © 2015, Central South University of Technology. All right reserved.