Enhanced dielectric and piezoelectric properties in BaZrO_3 modified BiFeO_3-PbTiO_3 high temperature ceramics

摘要

(0.67-x)BiFeO_3-0.33PbTiO_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 rhom-bohedral (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 ε_r, dielectric loss tan δ, piezoelectric constant d_(33), electromechanical coupling factor k_p were 540 ℃, 640, 0.02, 117 pC/N, 0.34, respectively. The depolarization temperature T_d was 470 ℃, about 320 ℃ higher than that of commercialized PZT ceramics, showing better electrical thermal stability.