Effects of Bi excess on the structure and electrical properties of high-temperature BiFeO3–BaTiO3 piezoelectric ceramics

BiFeO3–BTiO3(BF–BT) ceramics as a promising candidate for lead-free high-temperature piezoelectric ceramics were studied with a special emphasis on the compositional dependence of piezoelectric properties. Excess Bi was added to compensate for the evaporation of Bi3+ ions during sintering and this addition was found to be effective in improving the piezoelectric properties of BF–BT ceramics. The microstructure, dielectric and piezoelectric properties of excess Bi doped BF–BT ceramics were investigated. Maximum piezoelectric constant d 33 = 142 pC/N and k p = 0.302 were obtained with 0.04 Bi doping. At the same time, an enhanced Curie temperature T c, 452 °C, was obtained. The combination of improved piezoelectric properties and increased T c makes these ceramics suitable for elevated temperature piezoelectric devices.