Arc Erosion Behavior of Cu/Ti3SiC2 Cathodes in c-C4F8 Gas as a Substitute for SF6 Gas

In this paper, the arc erosion behavior of copper/titanium silicon carbide (Cu/Ti3SiC2) cathodes in air, sulfur hexafluoride (SF6) and octafluoroisobutane (c-C4F8) were investigated at 7.5 kV, and the possibility of c-C4F8 gas as a substitute for SF6 gas was assessed. The material was oxidized in air with large cracks, while it maintained a good structure in SF6 and c-C4F8, although there were some bulges in the erosion center. Fluorinated carbon (CFx) was detected in c-C4F8, which improved the arc erosion resistance. The arc extinguishing performance of different gases was analyzed by establishing the Mayr arc model and calculating the time constant θ and power loss coefficient N0. The results indicate that the time constant θ decreases in the order air > c-C4F8 > SF6, while the power loss coefficient N0 decreases in the order c-C4F8 > SF6 > air. An arc erosion mechanism was also proposed in this study.