Lead-free BF-BT ceramics with ultra-high Curie temperature for piezoelectric accelerometer.

Piezoelectric ceramics have been widely used in high precision sensors such as vibration detection, but piezoelectric accelerometers in high temperature applications are very rare. We prepared (1-x)BiFeO3-xBaTiO3-0.0035MnO2-0.001Li2CO3(BF-xBT) ceramics by a solid state approach, and investigated the effect of BT content(x) on the phase structure, microstructure, dielectric properties, ferroelectric properties, piezoelectric properties, temperature stability and especially the sensitivity of the piezoelectric accelerometer. The crystal structure of the sample is pure perovskite structure with the MPB (R and P phases) locating in a composition range of 0.28 ≤ x ≤ 0.32 for BF-xBT ceramics, and the single R phase exist at 0.20 ≤ x < 0.28. When x = 0.30, the ceramic presents both high Curie temperature and d33. Notably, the sensitivity of BF-0.30BT piezoelectric accelerometer reaches the highest value of about 40 pC/g and shows an excellent stability until 400 °C, indicating that this material is a promising candidate for high-temperature piezoelectric accelerometer applications.