Physical and piezoelectric properties of ceramics in the (K0.5Na0.5)NbO3–Bi(Zn0.5Ti0.5)O3–PbTiO3 system

Abstract

Piezoelectric ceramic materials in xKNN–yBZT–(1-x-y)PT system, when both of x and y were varied from 0.05 to 0.20, were prepared by a solid state reaction technique. Phase formation, microstructure, density, ferroelectric and piezoelectric properties of the specimens were investigated. The powders were calcined and sintered at the temperature of 900 oC for 6 h and 1050 oC for 2 h, respectively, to obtain single phase perovskite structures. The results indicated that the crystal structure of xKNN–yBZT–(1-xy)PT ceramics system changed from tetragonal to monoclinic phase while the secondary phase of PbTi2O7 was present at the composition of point 5 (0.2KNN–0.1BZT–0.7PT). The densities of the specimens tended to decrease with increasing KNN content. However, the densities and average grain sizes of their ceramics increased with increasing BZT content. In addition, the maximum values of piezoelectric and ferroelectric properties were achieved in 0.05KNN–0.05BZT–0.9PT compound, likely caused by the grain size effects.