Effect of zirconium content on the property of BCTZ lead-free piezoelectric ceramics

Ba_0.85Ca_0.15Ti_1-yZr_yO₃ (BCTZ) (y =0.05, 0.10, 0.15, 0.2) lead-free piezoelectric ceramics were prepared by conventional solid state method. Effects of Zr content on the piezoelectric and dielectric properties and microstructure of BCTZ lead-free piezoelectric ceramics were investigated. The results show that the average crystal grain size of BCTZ increases gradually, the crystal grain uniformity goes down; all the samples exhibit a pure perovskite structure and no trace of impurity phase was observed. The piezoelectric constant(d₃₃), the planar electromechanical coupling factor (k_p) of BCTZ ceramics increases first and then decreases, the relative permittivity (ε_r) increases gradually, the dielectric loss (tanδ) increases first and then decreases when Zr content increases. When Zr content (y) is 0.10, the BCTZ ceramics sintered at 1450, possess the best piezoelectric properties and dielectric properties whose d₃₃ is 424pC/N, k_p is 48.83%,ε_r is 4364, tanδ is 1.12%.