The degradation of barium titanate ceramics was studied at 150℃ under high AC electric field as a function of grain size controlled by changing of sintering time at 1375℃. The life time was decreased with grain size of 2.44-8.23㎛. Under the high applied voltage and temperature that effect degradation behavior, the life time was also decreased.
During the degradation process, AC conductivity kept constant and suddenly increased for the last period. The capacitance and dissipation factor were changed slightly. The former was slowly decreased and the latter was slowly increased.
As results, the mechanism of AC degradation of barium titanate ceramics seems to depend on the change of grain boundary property due to anion vacancy migration by electrostrictive force.
