Investigation of vacuum arc ignition characteristics and erosion morphology microstructure characteristics of CuCr55 electrode contact materials

Abstract

Copper–chromium alloy material, as one of the most important electrode contact materials in the field of electrical contact, has been widely used in vacuum interrupters. To replace the SF6 circuit breakers at higher voltage levels and larger breaking capacities, there is an urgent need for new electrode contact materials to meet the comprehensive electrical performance requirements of high withstand voltage, high insulation, and erosion resistance. In this study, a novel electrode contact material, CuCr55, for a 252 kV single break vacuum interrupter was prepared by the arc melting method, and the microstructures of arc-cast CuCr25, melt-infiltrated CuCr50, and arc-melted CuCr55 materials were compared. The vacuum arc ignition and erosion characteristics of arc-melted CuCr55 contact materials were analyzed in detail. A high-speed camera was used to capture the arc ignition characteristics of short-circuit currents, and the critical currents for the formation of anode spots for different materials were obtained. The micro-morphology of the contact surface after erosion was observed using electron microscopy. The research results showed that the arc-melted CuCr55 contacts had a fine and uniform distribution of chromium particles with spherical and dispersed microstructures. After vacuum arc erosion, there was no material fracture or significant protrusion on the surface of CuCr55 contacts, and they exhibited a higher critical current for anode spot formation and good uniform erosion characteristics.