Measurement of surface and volume resistivity for alumina ceramics under vacuum condition

This paper reported the surface and volume resistivity of typical insulators under atmospheric condition and vacuum condition. The measured materials are some kinds of alumina ceramics which have different purity of Al₂O₃ component. It was confirmed that the surface resistivity for almost all of the insulator materials under vacuum condition was higher than that under atmospheric condition. In addition, we checked the dependence of surface resistivity on ambient pressure from the atmospheric condition to the medium vacuum condition. Desorption of moisture vapor from the insulator surface would be the main cause of the increase of the surface resistivity in vacuum. On the other hand, the volume resistivity had little change between vacuum and atmospheric condition.