Structure, electrical properties of Bi(Fe, Co)O3–BaTiO3 piezoelectric ceramics with improved Curie temperature

Dense (1−y)BiFe1−xCoxO3–yBaTiO3 (BFC–BTx, y=0.29, x=0–0.012) high-temperature lead-free ceramics were prepared by the conventional oxide-mixed method and the effects of BiCoO3 modification on microstructural, electrical properties and their Curie temperatures were investigated. The solid solutions show a single phase perovskite structure, and the content of BiCoO3 has a significant effect on the microstructure of ceramics. The BFC–BTx ceramics exhibit improved Curie temperature Tc, together with increased piezoelectric properties. In particular, x=0.6% BFC–BTx ceramics, with a Curie temperature, Tc, of ∼488 °C, show optimum piezoelectric properties of d33=167 pC/N, kp=0.32. The combination of good piezoelectric properties and high Tc makes these ceramics suitable for elevated temperature piezoelectric devices.