LAUSR

Abstract To investigate the effect of pores on the dielectric breakdown (DB) of alumina ceramics under AC voltage, we implant pores at different positions (surface, interior, and the whole body) of the ceramic samples by adding the polyvinyl alcohol solid particles at different positions in the green bodies. Meanwhile, two electrode setups are used to test the dielectric breakdown strength (DBS), in order to analyze the effect of pore distribution on the DB, and the morphology of the DB channels is characterized. The results reveal both the pores on the surface and in the bulk reduce the DBS, and the pore distribution affects the shape and position of the DB channel. Besides, pre-breakdown in a low-DBS layer is found when the voltage is not high enough to produce DB. It confirms that the effect of pores on the DB is a combination of the volume effect and the surface effect.