Enhanced electromechanical properties and thermal stability of antimony-modified BiScO₃-PbTiO₃ high-temperature piezoelectric ceramics

The search for a suitable donor dopant to improve the piezoelectric response of BiScO₃-PbTiO₃ (BS-PT) piezoelectric ceramics without sacrificing temperature stability is crucial for developing high-temperature piezoelectric materials for the application in the elevated temperature. In this study, the effects of Sb⁵⁺ donor doping on the microstructure, dielectric, ferroelectric, piezoelectric and electromechanical properties of the BS-PT ceramics were investigated. It was found that the Sb⁵⁺ dopant acts as the grain growth inhibitor, resulting in a dense and fine-grain microstructure. An enhanced piezoelectric properties d₃₃ of 535 pC N⁻¹ with a high T_c of 440 °C was simultaneously achieved in 0.25 mol%Sb⁵⁺ doped BS-PT (BSPT-0.25Sb) ceramic. The results of in-situ piezoelectric constants and electromechanical coupling coefficients as a function of temperature indicate that the BSPT-0.25Sb ceramic has a high depolarization temperature T_d of 400 °C, which is much higher than those of the most widely used PZT-based piezoelectric ceramics. Furthermore, BSPT-0.25Sb ceramic has much higher resistivity and lower dielectric loss than PZT-4 and PZT-8 at high temperature. The excellent piezoelectric properties and thermal stability of the BSPT-0.25Sb ceramic indicate that it is a promising piezoelectric material for high-temperature applications.