High temperature properties of BiScO3-PbTiO3 piezoelectric ceramics

Smart actuators and intelligent structures are sought after for aeronautical applications. As a result of high Curie temperature (430 degrees C) and piezoelectric coefficient (>200 pC/N), BiScO3-PbTiO3 (BS-PT) ceramics are prospective materials for high temperature actuators. This paper reports on the temperature dependent electrical, ferroelectric, and electromechanical properties of liquid phase sintered BS-PT ceramics. Compared to solid state sintered BS-PT, liquid phase sintered BS-PT with Bi2O3 showed improved electrical performance: (1) threefold reduction in loss tangent at elevated temperatures, (2) fivefold increase in dc resistivity at high electrical fields, and (3) 15% increase in high field piezoelectric coefficient. Hysteresis loops of the highly resistive ceramics were saturated and showed no major dependence on the magnitude and the frequency of the applied field. BS-PT ceramics exhibit depoling behavior at temperatures below (>350 degrees C) the Curie temperature (430 degrees C). Liquid phase sintering using excess Bi2O3 is shown to be a promising approach to produce superior BS-PT ceramics for high temperature actuators.