High temperature piezoelectric accelerometer fabricated by 0.75BiFeO3–0.25BaTiO3 ceramics with operating temperature over 450 °C

Owing to the high Curie temperature and good piezoelectric thermal stability, BiFeO3–BaTiO3 ceramics show great potentials for high-temperature piezoelectric sensor applications. In this paper, a compression-mode piezoelectric sensor was fabricated by the lead-free and high-temperature 0.75BiFeO3–0.25BaTiO3–MnO2 (BFBT25–Mn) ceramic and its sensitivity was characterized from room temperature to 550 °C over a frequency range of 200–1000 Hz. The output charge of the BFBT25–Mn piezoelectric sensor is independent of the measuring frequency at different temperatures. The maximum working temperature of the BFBT25–Mn piezoelectric sensor is 450 °C, about 250, 150, and 100 °C higher than those of these piezoelectric sensors fabricated by PZT-5A, BSPT64–Mn, and BSPT66–Mn ceramics, respectively. The temperature sensitivity coefficient from room temperature to 350 °C of the BFBT25–Mn piezoelectric sensor is 30% of that for the BSPT66–Mn sensor. Furthermore, the sensitivity of the BFBT25–Mn piezoelectric sensor is stable with the dwelling time at 400 °C. These results indicate that the BFBT25–Mn ceramic is a strong competitor for high temperature sensing applications.