Influences of preparation technology on the flashover characteristics of machinable ceramics in vacuum

This paper probes into the influences of preparation technology, mainly crystallization time, on the flashover characteristics of machinable ceramics under 0.4/2.5 mus impulse voltage in vacuum. Several machinable ceramic samples are prepared with the same procedure under different crystallization time. To study the association between crystallization time and flashover characteristics, the surface microstructures of samples are observed by SEM, while the surface electric strength of each sample is tested by flashover experiments in vacuum. It is revealed that the flashover characteristics vary with their crystallization time, and the sample with less crystallization time has a better flashover performance. From the SEM analysis of the samples, the crystallization time of machinable ceramic can affect its microstructure. The longer crystallization time is, the bigger grains will grow. And this will contribute to an influence on the flashover performance of machinable ceramics.