Arc erosion resistance of WC/CuCr30 composites based on changing of Cr particle morphology and orientation

Abstract

CuCr30 composite was commonly applied in medium and low voltage vacuum interrupters. The WC/CuCr30 composites based on changing of Cr particle morphology and orientation were successfully prepared by vacuum hot press sintering and hot extrusion, and the arc erosion resistance behavior at different voltages along the deformation direction of Cr particles was investigated on the JF04C electrical contact material testing system. The microstructure characterization of WC/CuCr30 composites shows that the Cr particles in the WC/CuCr30 composite have been elongated and the long axis direction is close to parallel to the extrusion direction after the hot extrusion deformation. Compared with the longitudinal section, the thermal conductivity of CuCr30 and WC/CuCr30 composites in the cross section is increases by 3.75% and 3.63%, respectively. The electrical contact testing results under different voltages shows that the addition of WC particles can extend the service life of the CuCr30 composite, and the operation times of WC/CuCr30 composite (4850 times) increases by 34.72% compared to CuCr30 composite (3600 times) at 30 V DC. The welding force decreases more obviously with the increase of the voltage, and the average welding force of WC/CuCr30 composite decreases by 8.57% and 20.9% at 24 V DC and 30 V DC compared with CuCr30, respectively. The arc erosion mechanism analysis shows that addition of WC particles is beneficial for the decrease of arc duration. And WC particles can effectively inhibit the arc erosion process and delay the formation of bumps and pits.

Keywords

• Cr particle orientation
• Arc erosion
• WC/CuCr30 composite
• Thermal conductivity
• Welding resistance