Effect of different surface treatment on the surface flashover characteristics of machinable ceramic in vacuum

Surface flashover phenomena in vacuum restrict the overall performance of insulation system, which seriously limits the development of high voltage electro-vacuum devices. On the basis of the novel low melting temperature machinable glass ceramics for vacuum insulation system, which has excellent machinable performance and good electrical properties, the different types of sandpaper are used in this paper to treat on the sample surface. The surface pattern and the surface roughness of the machinable ceramic samples have been measured by a confocal laser microscope, and the flashover characteristics of the samples in vacuum have been measured in this paper. The results indicated that, the sandpaper treatment can change the surface roughness of samples effectively, with the increasing of the surface roughness, the flashover voltage of the machinable sample increased gradually.