Effect of chromium oxide coating on surface flashover characteristics of ceramic in vacuum

Experiments were conducted to determine the conditioning effects of a chromium oxide coating on a ceramic surface. Chromium oxide is known to have a small secondary electron emission coefficient. With a chromium oxide coating, conditioning effects were completed early and flash over voltage increased. While luminescence was observed on a bare ceramic surface under a high applied voltage, none was observed on the sample coated with chromium oxide. One cause of increasing flashover voltage due to coated chromium oxide is depression of the secondary electron avalanche. Another is considered to be depressed surface charge due to decreasing surface resistance