Morphotropic phase boundary and high temperature dielectric, piezoelectric, and ferroelectric properties of (1-x)Bi(Sc_3/4In_1/4)O ₃-xPbTiO₃ ceramics

Piezoelectric ceramic (1 - x)Bi(Sc_3/4In_1/4)O _3-xPbTiO₃ (BSIPT) (0.45 ≤ x ≤ 0.70) solid solutions near the morphotropic phase boundary (MPB) were developed for high temperature piezoelectric transducer and actuator applications. It was found that the MPB composition of BSIPT ceramics was in the vicinity of x 0.6, where it had relatively small tolerance factor t 0.901 resulting in a high T_C of 457°C, and also optimal properties such as the high P_r = 25.4 μC/cm², ε_r = 1153, d₃₃ = 201 pC/N, k_p = 0.34, and the low E_c = 23.5 kV/cm. Measurements also showed that the depoling temperature was 360°C, about 200°C higher than that of commercialized PZT ceramics, which indicated good temperature stability. BSIPT ceramics are promising candidates for high temperature applications.