Effect of surface ion exchange of machinable ceramic on its flashover characteristics in vacuum

As well known, the surface conditions of solid materials strongly affect the flashover phenomena under high electric field in vacuum. 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 ion-exchange method was used to change the sample´s surface condition, surface electric resistivity and surface trap density. Different alkali metal ions were used in this paper, and this may change the sample´s surface microscopic structure. We have measured the different sample´s surface flashover in vacuum, and investigated the relationship between the ion-exchange method and sample´s surface electricity characteristic. The results indicated that while using suitable ion-exchange method, the sample´s surface flashover performance can be improved.