Temperature stability and phase transition of Li0.02(KxNa1−x)0.98NbO3 ceramics

Li0.02(KxNa1−x)0.98NbO3(x = 0.35–0.55) ceramics were prepared using the conventional solid state sintering method. The thermal behaviors of Li-modified (KxNa1−x)NbO3 ceramics were investigated from −30 to 150 °C, and the effect of Na/K ratio in (KxNa1−x)NbO3 ceramics on thermal behavior and electrical properties was also studied. In the case of Li0.02(KxNa1−x)0.98NbO3 ceramics with 0.5 wt.% ZnO, the transition temperature was sharply decreased because of a phase transition as the composition range of x was 0.425–0.475. From the results of the temperature dependence of piezoelectric properties, it is assumed that the Na-rich phase is less stable than the K-rich phase for temperature change.