抄録
Electric fatigue of ferroelectric ceramics, PZT 5 (Pb[Zr48,Ti52]O3) subjected to bipolar cyclic electric loading is examined. The central through-thickness crack specimens with different inclined angles were loaded by alternate electric fields. For all inclined angles, the crack was found to deflect away from the original plane, similarly to the mechanical fatigue of brittle materials. The number of cycles required for the crack to propagate was dependent upon the magnitude of the electric field as well as the inclination angle of the inclined crack. It was found that crack propagation would come to a standstill only when the applied electric field was below the coercive field. The dominant cause of electric fatigue due to a cyclic electric field below the coercive field is believed to be strain mismatch. Whereas, for the case of applied electric field above coercive field the dominant cause is likely to be electric breakdown.
