BiFeO3-PbZrO3-PbTiO3 ternary system for high Curie temperature piezoceramics

BiFeO3-PbZrO3-PbTiO3 ternary solid solution system was investigated for the development of piezoelectric ceramics with high Curie temperatures. The search for the morphotropic phase boundary (MPB) compositions in this ternary system started from mixing two MPB compositions: 0.70BiFeO3-0.30PbTiO3 and 0.52PbZrO3-0.48PbTiO3. The content of PbTiO3 was then further fine tuned in order to reach the appropriate volume fraction between the rhombohedral and tetragonal phases in the sintered ceramics. It was observed that the sintering temperature has a profound impact on the density, grain morphology, dielectric and ferroelectric properties of the ceramics. The composition that displays the best combined structure and properties was identified to be 0.648BiFeO3-0.053PbZrO3-0.299PbTiO3, with a Curie temperature TC of 560 °C, a remanent polarization Pr of 15.0 μC/cm2, and a piezoelectric coefficient d33 of 64 pC/N.