Enhanced electrical properties of lead-free (Ba_1−xCa_x)(Ti_0.94Zr_0.01Sn_0.05)O₃ piezoelectric ceramics by optimizing phase ratio and sintering temperature

It is challenging for material chemists to develop lead-free ceramics due to the toxicity of lead for human health and environment. (Ba, Ca)(Ti, Zr)O₃ and (Ba, Ca)(Ti, Sn)O₃ lead-free piezoelectric ceramics have attracted much attention due to their superior piezoelectric properties. In this study, Ca²⁺, Zr⁴⁺ and Sn⁴⁺ were simultaneously doped at A-sites and B-sites, respectively, to clarify the structure and enhance the electrical performance. (Ba_1−xCa_x)(Ti_0.94Zr_0.01Sn_0.05)O₃ (BC_xTZS) lead-free piezoelectric ceramics were successfully fabricated by conventional solid-state reactive sintering method. The effects of Ca²⁺ content (x) and sintering temperature on microstructure, phase structure and electrical properties of BC_xTZS were investigated. Herein, BC_xTZS ceramics are the coexistence of R-O phases as 0.01 ≤ x ≤ 0.02, and they become O-T phases as 0.02 < x ≤ 0.08. The excellent electrical performances with d₃₃ = 511 pC N⁻¹, k_p = 43% and Q_m = 126 were achieved by optimizing the phase ratio and sintering temperature. The superior d₃₃ along with the comparable Q_m with PZT ceramics indicates that BC_xTZS ceramics are promising lead-free piezoelectric ceramics.