Effect of laser treatment on the surface flashover characteristics of alumina ceramic in vacuum

As well known, the surface conditions of solid materials strongly affect the flashover phenomena under high electric field in vacuum. In this paper, the laser treatment was used to scratch lines on the surface of the alumina ceramic to investigate the influence of the laser treatment on the sample surface. We found that after scratched by the laser the flashover voltage on the surface of the ceramic changed obviously. Experimental results revealed how the scratched lines depth and the scratched lines density affected the flashover voltage characteristic. The results indicated that while the depth and the density of the scratched lines regulated suitably and there showed a regular microstructure on the surface of the ceramic, the flashover voltage of the alumina ceramic in vacuum shows the best performance.