Effect of LiSbO3 and SrZrO3 doping on the piezoelectric properties and microstructural behavior of K0.5Na0.5NbO3 ceramics

The effect of LiSbO3 and SrZrO3 doping on the piezoelectric characteristics of K0.5Na0.5NbO3-based ceramics was studied. First, (1 − x)K0.5Na0.5NbO3–xLiSbO3–CuO (0.00 ≤ x ≤ 0.07) was synthesized and a single phase of perovskite was observed in the range of 0.00 ≤ x ≤ 0.05. As LiSbO3 content increased, the orthorhombic single phase changed to orthorhombic and tetragonal multiphase. TO–T decreased from 176 °C (x = 0.00) to 85 ℃ (x = 0.05) and, the d33 showed the highest value of 156 pC/N (x = 0.05). Next, (0.95K0.5Na0.5NbO3–0.05LiSbO3)–xSrZrO3–CuO (0.00 ≤ x ≤ 0.05) was studied. All compositions were well synthesized as perovskite phases; orthorhombic and tetragonal mixed phases up to x = 0.02, rhombohedral, orthorhombic, and tetragonal mixed phases at x = 0.03 and 0.04; and rhombohedral and tetragonal phases at x = 0.05. TO–T decreased from 78 ℃ (x = 0.00) to 32 ℃ (x = 0.04), and TR–T was formed at 48 ℃ (x = 0.05). The d33 value at x = 0.04 was 288 pC/N and significantly reduced to 134 pC/N at x = 0.05.