Partial discharge, microcracking, and breakdown in BaTiO3ceramics

Pure barium titanate ceramics was subjected to partial discharge and dielectric breakdown test. Local field enhancement at the pores lowered the partial discharge inception field and breakdown strength. After applying 50% of the breakdown voltage, microcracks were formed by the shear stress set up at blocked ferroelectric twin bands. When the discharge current at the pores under high voltage exceeds a critical value, it results in immediate thermal destroy of BaTiO3 ceramics. Morphology of the breakdown channel in barium titanate ceramics was observed.