Dielectric and Piezoelectric Properties of (A0.5Bi0.5)TiO3–ANbO3 (A=Na, K) Systems

The microstructural, dielectric and piezoelectric properties of the (Na0.5Bi0.5)TiO3–NaNbO3 and (K0.5Bi0.5)TiO3–KNbO3 systems were studied in order to find new lead-free piezoelectric ceramic materials. In the (1-X) (K0.5Bi0.5)TiO3–(X) KNbO3 system, it was confirmed from the measurements of the electromechanical coupling factor, Kp, that piezoelectricity occurred within the wide compositional range between X=0 and 0.35. The sample with X=0.075 showed a maximum Kp of 15.1%. However, the expected morphotropic phase boundaries were not found in the (Na0.5Bi0.5)TiO3 or (K0.5Bi0.5)TiO3 rich side of the solid solution systems.