Effect of ZnO Addition on Dielectric and Piezoelectric Properties of (Ba_0.85Ca_0.15)(Ti_0.915Zr_0.085)O₃ Ceramics

Abstract

Lead-free (Ba_0.85Ca_0.15)(Ti_0.915Zr_0.085)O₃ + x wt%ZnO piezoelectric ceramics were synthesized using a conventional solid state sintering method and the effect of ZnO addition on their piezoelectric and dielectric properties was investigated. The X-ray diffraction date exhibited that ZnO diffuses into the lattice of (Ba_0.85Ca_0.15)(Ti_0.915Zr_0.085)O₃ (abbreviated as BCTZ) and pure perovskite structure phase was formed at all the specimens, And no secondary phases are observed in the measurement range of XRD. In addition, all the specimens showed tetragonal phase structure. The Curie temperature of BCTZ ceramics decreases with increasing the ZnO content. At the 0.2 wt% ZnO added (Ba_0.85Ca_0.15)(Ti_0.915Zr_0.085)O₃ ceramics sintered at 1360°C, the optimized piezoelectric properties were obtained; piezoelectric constant(d₃₃) = 348 [pC/N], dielectric constant(ϵ_r) = 3263, mechanical quality factor(Q_m) = 267, electromechanical coupling factor(k_p) = 0.41, respectively.

Keywords:

• Lead-free ceramic
• BCTZ
• piezoelectric properties
• ZnO