Enhanced dielectric and piezoelectric properties in BaZrO3 modified BiFeO3-PbTiO3 high temperature ceramics

(0.67-x)BiFeO3-0.33PbTiO(3)-xBaZrO(3) (BF-PT-BZ) ceramics were prepared by conventional solid state reaction method. X-ray diffraction analysis indicated that a phase transformation from tetragonal (T) to rhombohedral (R) took place with increasing the BZ content, and the coexistence of two phases were observed near the composition range from 0.08 to 0.12. Introduction of BZ reduced the c/a ratio, decreased the grain size, and improved the dielectric as well as piezoelectric properties obviously. Both high Curie temperature and good electrical properties were obtained in the BF-PT-BZ solid solutions with x = 0.08. The Curie temperature T (C), dielectric constant epsilon (r), dielectric loss tan delta, piezoelectric constant d (33), electromechanical coupling factor k (p) were 540 A degrees C, 640, 0.02, 117 pC/N, 0.34, respectively. The depolarization temperature T (d) was 470 A degrees C, about 320 A degrees C higher than that of commercialized PZT ceramics, showing better electrical thermal stability.