The effect of metal particles on surface flashover characteristics of alumina ceramic under pulse voltage in vacuum

Metal particles play a significant role in inducing surface flashover of insulators. Alumina ceramic is commonly utilized as an insulator in electrical vacuum equipment due to its high insulation and corrosion resistance properties. To ensure the safe operation of such equipment, it is imperative to investigate the impact of metal particles on the flashover characteristics of alumina ceramics. In this study, we conducted measurements on the surface flashover voltage of alumina ceramic under pulse voltage in a vacuum chamber with metal particles attached to various positions on the ceramic surface. Our experimental findings demonstrate that the presence of metal particles reduces the flashover voltage, and longer particle lengths result in lower flashover voltages. Furthermore, our results indicate that metal particles located near the cathode have a greater impact on flashover voltage than those located elsewhere. The phenomenon was analyzed through numerical simulation of the electrostatic field, elucidating the mechanism by which particles affect the surface flashover voltage of alumina ceramic. This provides a practical and simulation foundation for comprehending the factors that influence surface flashover.