Effect of New Phase Boundary on the Dielectric and Piezoelectric Properties of K0.5Na0.5NbO3- xBaZrO3- yBi0.5Na0.5TiO3Lead-free Ceramics

Abstract

(1-x-y)K0.5Na0.5NbO3- xBaZrO3- yBi0.5Na0.5TiO3 ceramics (abbreviated as KNN-x, y) were prepared by the conventional solid state reaction method. BaZrO3 results in the increase of T R-O, and Bi0.5Na0.5TiO3 leads to the decrease of T O-T. The ceramics co-modified with these two additives exhibit a new phase boundary. With the shrinkage of O phase in the R–O–T phase structure, the first order O-T phase transition evolved to the secondary order R-T phase transition according to the thermal hysteresis. Enhanced piezoelectric properties (d 33 = 348 pC/N and k P = 43.2%) were obtained near the new phase boundary when x = 0.04 and y = 0.025.