Temperature stability of sodium-doped BiFeO3–BaTiO3 piezoelectric ceramics

An enhancement in piezoelectric properties of lead-free ceramic materials by compositional engineering is often accompanied by a sacrifice in the temperature-stability of properties. Here we demonstrate that high piezoelectric properties and excellent high-temperature stability are obtained simultaneously in 0.72BiFeO3–0.28Ba1−xNaxTiO3 (BF–BTNx, x = 0–0.035) ceramics. Our results show that the high temperature-stable piezoelectric properties from 26 to 470 °C, combined with room temperature high piezoelectric constant d33 = 165pC/N and electromechanical coupling factor kp = 0.35 are achieved for x = 0.015 BF–BTNx ceramics. The results suggest Na-doped BF–BT system ceramic is a potential candidate for high temperature harsh environments actuators and sensors applications.