Excellent comprehensive piezoelectric performances of SiC-doped BCTZ-based lead-free piezoelectric ceramics

With increasing awareness of environmental protection, the electrical performance and sintering process of lead-free piezoelectric ceramics are continuously optimized to replace lead-based materials. Exploring an appropriate doping strategy is believed to achieve concurrent improvements in lead-free piezoelectric ceramics. In this work, SiC was selected to optimize the phase structure, defect configuration, and morphology of (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ (BCTZ) lead-free piezoelectric ceramics. On the one hand, SiC could promote the sintering process and grain growth due to its excellent thermal conductivity, resulting in the compactness and outstanding insulation of the doped ceramics. On the other hand, the incorporation of Si⁴⁺ in the B-site of the ABO₃ lattice not only deforms the crystal structure and enhances the lattice distortion but also reduces the oxygen vacancy concentration and increases the charge carrier activation energy. As a result, excellent comprehensive piezoelectric responses of piezoelectric coefficient (d₃₃) = 638 pC/N, inverse piezoelectric coefficient (d₃₃*) = 1048 pm/V, planar electromechanical coupling coefficient (k_p) = 58.21%, and Curie temperature (T_c) of ~95 °C were achieved with the optimized composition. Our work demonstrated that SiC-doped BCTZ-based ceramics are potential candidates for replacing lead-based piezoceramics.