Dielectric and piezoelectric properties of Y2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free piezoelectric ceramics

Y2O3 doped lead-free piezoelectric ceramics (Bi0.5Na0.5)(0.94)Ba0.06TiO3 (0-0.7 wt%) were synthesized by the conventional solid state reaction method, and the effect of Y2O3 addition on the structure and electrical properties was investigated. X-ray diffraction shows that Y2O3 diffuses into the lattice of (Bi0.5Na0.5)(0.94)Ba0.06TiO3 to form a solid solution with a pure perovskite structure. The temperature dependence of dielectric constant of Y2O3 doped samples under various frequencies indicates obvious relaxor characteristics different from typical relaxor ferroelectric and the mechanism of the relaxor behavior was discussed. The optimum piezoelectric properties of piezoelectric constant d(33) = 137 pC/N and the electromechanical coupling factor k(p)=0.30 are obtained at 0.5% and 0.1% Y2O3 addition, respectively. (C) 2008 Elsevier Ltd. All rights reserved.