Dielectric And Piezoelectric Properties Of Y_2o_3 Doped (bi_(0.5)na_(0.5))_(0.94)ba_(0.06)tio_3 Lead-free Piezoelectric Ceramics

摘要

Y_2O_3 doped lead-free piezoelectric ceramics (Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_3 (0-0.7 wt%) were synthesized by the conventional solid state reaction method, and the effect of Y_2O_3 addition on the structure and electrical properties was investigated. X-ray diffraction shows that Y_2O_3 diffuses into the lattice of (Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_3 to form a solid solution with a pure perovskite structure. The temperature dependence of dielectric constant of Y_2O_3 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_ρ = 0.30 are obtained at 0.5% and 0.1% Y_2O_3 addition, respectively.