High Temperature Piezoelectric Ceramics Based on xPbTiO3-(1-x)Bi(Sc1/2Me1/4Ti1/4)O3(Me = Zn, Mg) Ternary Perovskites

Polycrystalline xPbTiO(3)-(1 - x) Bi(Sc1/2Me1/4Ti1/4)O-3(PT-BS-BMeT) ceramics, where Me = Mg (M) or Zn (Z), were studied for development of high temperature piezoelectrics. Ceramics were processed using standard mixed oxide procedure at various temperatures. X-ray diffraction at room temperature revealed that the tetragonality of PT-BS-BZT decreased as PbTiO3 content decreased from x = 0.90 to 0.60 and tetragonality of PT-BS-BMT decreased as PbTiO3 content decreased from x = 0.60 to 0.40. A transition was observed in PT-BS-BMT within compositions x = 0.42-0.50. Dielectric properties revealed permittivites up to epsilon(r) approximate to 20000 and transition temperatures up to 540 degrees C. Hysteresis measurements showed full saturation below 50 mol% PbTiO3 content with remanent polarization of P-r = 32.8 mu C/cm(2) and coercive field of 23.0 kV/cm. Converse piezoelectric coefficients (d(33)*) calculated from unipolar strain measurements revealed values between 240 and 313 pm/V. Depolarization temperatures were measured between 320 and 390 degrees C. (C) 2012 The Japan Society of Applied Physics