Effect of polarization treatment on bending strength of barium titanate/zirconia composite

The change in strength of barium titanate/zirconia composite on polarization treatment is evaluated, and the mechanism of this phenomenon is discussed. We have already reported that the bending strength of this composite has increased on longitudinal poling. In this paper, poling time and applied electric field intensity are varied in order to elucidate the strengthening mechanism. Moreover, it is found out that the polarization strengthened specimen can be weakened to the almost original state by heating above Tc of barium titanate. Then, the crack propagation after polarization treatment is observed by SEM, and the detour of cracks around barium titanate grains is found in the cracks going along the poling direction. The detour of crack probably has close connection with the increase in strength in the poling direction.