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

Novel perovskite xBiYbO(3)-(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 degrees C and the optimum sintering temperature is 1140 degrees 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 100700 at room temperature and tan 3 less than 4%. BYPT ceramics with high Curie temperatures of >500 degrees C are obtained. 0.1 BiYbO3-0-9PbTiO(3) ceramic is a very promising material for high-temperature (up to 550 degrees C) piezoelectric applications for high T-c, stable d(33), and high thermal-depoling temperature. (C) 2008 Elsevier Ltd. All rights reserved.