Studies on (Ba-Pb)(Ti-Zr)O₃ System

Abstract

Structural studies on (Ba-Pb)(Ti-Zr)O₃ system were performed, and the phase diagram of the whole system was determined. In the vicinity of BaTiO₃, low temperature phases are brought to room temperature by adding Pb and Zr. Substituting some amount of Pb by Ba in Pb(Ti-Zr)O₃, Curie point becomes lower, but the morphotropic boundary between F_α and F_β Phase shifts only gradually to the Ti side, and may lie nearly at the same composition with varying temperature. The axial ratio in F_β phase decreases with decreasing Ti concentration, while 90°–a in F_α decreases with increasing Ba and hardly depends on Ti-Zr ratio.
Some solid solution ceramics along the morphotropic bundary with Ba 5–20% and Ti 40–50% are excellent for piezoelectric materials, and those containing Ba ca. 30% and Ti 5–25% have large dielectric constants and low temperature coefficients.