Arc erosion behavior and mechanism of Ag/Ti3SiC2 cathodes in different atmospheres

Abstract

Novel Ag matrix electrical contacts, which are environment-friendly, are required to operate under complex service conditions and harsh environments. Therefore, it becomes necessary to urgently study their arc erosion properties in different atmospheres. Herein, Ag/Ti3SiC2 composite samples were fabricated by hot-pressing sintering, and the material's relative density, electrical resistivity, thermal conductivity, Brinell hardness, and flexural strength were measured. Moreover, the arc erosion behaviors of Ag/Ti3SiC2 cathodes in sulfur hexafluoride, nitrogen, and oxygen environments were investigated at 3 kV and 6 kV, and the mass loss, arc current, and discharge duration of the Ag/Ti3SiC2 cathodes in the 3 atm were recorded. The surface morphology and composition of the Ag/Ti3SiC2 cathodes were examined after arc erosion. In this study, the arc energy and mass loss had the highest values in oxygen, followed by nitrogen and sulfur hexafluoride. Following the same trend of operating atmospheres, the erosion-region shape gradually changed from circular to irregular. By means of the Raman spectra, there was no composition change can be detected on the cathode in sulfur hexafluoride, TiNx was detected on the cathode in nitrogen, Ag2O, TiO2 and SiO2 were found on the cathode in oxygen. The resistance of the cathode material to arc erosion deteriorated gradually in the sulfur hexafluoride, nitrogen, and oxygen environments. Importantly, the arc erosion mechanism of the Ag/Ti3SiC2 cathodes in different atmospheres is also proposed in this study. This research can provide a reference for the applications of environmentally friendly Ag matrix electrical contact materials in different atmospheres.