Surface Flashover Performance of Ion-exchanged Machinable Glass Ceramics Material in Vacuum

Under the high electric field, discharge sometimes occurs along the surface of solid in vacuum, gas or liquid dielectrics, which is called surface flashover.SiO2-B2O3-K2O-Li2O-Al2O3-ZnO-MgO-F system glass ceramics has great machinability and excellent dielectronic property. This paper tries to study different time of ion-exchanged samples and their microstructures, which affect surface flashover performance of this novel material under the systerm of high voltage in vacuum. Compared to traditional coating method on alumina ceramic, the ion exchange treatment on glass ceramic can produce a tremendous improvement of flashover characteristics. The results show that the 10 hours ion-exchanged glass ceramic enjoys the most prominent insulation strength. Based on the theory of SEEA (Secondary Electron Emission Avalanche), these phenomena can be reasonably explained by the charge carrier injection and transport behaviors.