Superior piezoelectric performance with high operating temperature in bismuth ferrite-based ternary ceramics

Due to the thermal depolarization effect, adequate piezoelectric performance with high operating temperature is regarded to be challenging to accomplish concurrently in piezoceramics for applications in specific piezoelectric devices. In this work, we synthesized (0.8−x)BiFeO₃-xPbTiO₃–0.2Ba(Zr_0.25Ti_0.75)O₃ (abbreviated as BFO-xPT-BZT) ternary solid solutions with 0.15 ≤ x ≤ 0.30 by conventional solid-state reaction method. The MPB composition with a coexisting state of rhombohedral-tetragonal phases exhibits enhanced electromechanical properties, including Curie temperature of 380 °C, large-signal equivalent piezoelectric coefficient d₃₃^* of 395 pm V^–1, small-signal piezoelectric coefficient d₃₃ of 302 pC N^–1, and electromechanical coupling factor k_p of 50.2%, which is comparable to commercial PZT-5A ceramics, indicating potential in high-temperature applications. Furthermore, in-situ X-ray diffraction (XRD) and piezoelectric force microscopic (PFM) techniques demonstrate that multiphase coexistence and complex nanodomains promote piezoelectric response via synergism. The x = 0.24 composition exhibits the highest in-situ d₃₃ of 577 pC N^–1 and good temperature stability in 30−280 °C, indicating that BZT-modified BFO-PT ceramics are promising candidates for high-temperature piezoelectric devices.