Piezoelectric Properties and Depolarization Temperatures of (Bi{sub}(1/2)Na{sub}(1/2))TiO{sub}3-(Bi{sub}(1/2)K{sub}(1/2))TiO{sub}3-BaTiO{sub}3 Lead-Free Piezoelectric Ceramics

摘要

The piezoelectric properties of a solid solution based on the three components of bismuth sodium titanate, (Bi{sub}(1/2)Na{sub}(1/2))TiO{sub}3 (BNT), bismuth potassium titanate, (Bi{sub}(1/2)K{sub}(1/2))TiO{sub}3 (BKT), and barium titanate, BaTiO{sub}3 (BT), that is, x(Bi{sub}(1/2)Na{sub}(1/2))TiO{sub}3-y(Bi{sub}(1/2)K{sub}(1/2))TiO{sub}3-zBaTiO{sub}3 [BNBKy:z(x); x+y+z=1] are investigated. Fine piezoelectric properties in lead-free piezoelectric ceramics were obtained near the MPB composition, and the highest electromechanical coupling factors, k{sub}33 and k{sub}p, and piezoelectric constant, d{sub}33, were 0.58 and 0.36 for BNBK2:1(0.89) and 181 pC/N for BNBK2:1(0.88), respectively. In this study, we also measured the depolarization temperature, T{sub}d, from the temperature dependence of dielectric and piezoelectric properties.