Influence of Phase Composition on the Piezoelectric Properties of PMN-PT Ceramic

The influence of chemical and phase composition on the piezoelectric properties of PMN-PT ceramics with chemical compositions near the morphotropic phase boundary(MPB) sintered at different temperatures was investigated. It showed that a phase conversion from rhombohedral to tetragonal phase took place when the sintering temperature of PMN-PT ceramic with a definite chemical composition increased. Meanwhile, the piezoelectric properties of PMN-PT ceramics were significantly enhanced when the amount of rhombohedral phase approached to that of tetragonal phase in ceramics. At the same time, it was discovered that the chemical composition corresponding to optimal piezoelectric properties varied with the change of sintering temperature. Based on above results, the authors found that the piezoelectric properties of PMN-PT near the MPB are not only related to the chemical composition but also significantly impacted by the phase composition in ceramics. With the change of sintering temperature, the MPB of PMN-PT ceramic system shifts slightly.