Phase formation and characterization of high Curie temperature xBiYbO3–(1 − x)PbTiO3 piezoelectric ceramics

Novel perovskite xBiYbO3–(1 − x)PbTiO3 (BYPT) crystalline solutions were prepared by conventional ceramic processing. The effect of BiYbO3 on the microstructure and electrical properties was investigated, and the reaction mechanism of phase formation was discussed. The results show that the proper calcining temperature is 860 °C and the optimum sintering temperature is 1140 °C. It is difficult for BYPT ceramics to obtain phase-pure perovskite structures. Pyrochlore phase Yb2Ti2O7 was formed by Yb2O3 and TiO2 that decomposed from BiYbO3–PbTiO3 at high temperature. With increasing BiYbO3 content, the pyrochlore phase Yb2Ti2O7 increases, which resulted in the decrease of densities and piezoelectric constants. The dielectric constants were in the range of 100–700 at room temperature and tan δ less than 4%. BYPT ceramics with high Curie temperatures of >500 °C are obtained. 0.1BiYbO3–0.9PbTiO3 ceramic is a very promising material for high-temperature (up to 550 °C) piezoelectric applications for high Tc, stable d33, and high thermal-depoling temperature.