Phase structure, domain structure, thermal stability, and high-temperature piezoelectric response of BiFeO3-BaTiO3 lead-free piezoelectric ceramics

High-temperature lead-free piezoceramics with a large piezoelectric constant d33 and a high depolarization temperature Td have long been a target of ferroelectric researchers. In this work, (1-x)BiFeO3-xBaTiO3 ceramics with MnO2 and Li2CO3 additives (BF-xBT) were fabricated with traditional ceramic preparation technology. The best piezoelectric ferroelectric properties and thermal stability d33 = 185 pC/N, Pr = 33.152 mu C/cm2, Tc = 470 degrees C, and Td = 460 degrees C were obtained for x = 0.32. The tetragonal (T) phase content of BF-xBT ceramics increases gradually with an increase of BT content, and the temperature stability improves. In particular, an in-situ d33 test indicates that BF-xBT ceramics have large piezoceramics coefficients with d33 = 450.5 pC/N at a temperature of T = 334 degrees C. Piezo force microscopy and transmission electron microscopy tests show that nanodomains and polar nanoregions play a key role in the improvement of piezoelectric response. BF-xBT ceramics appear to be the most promising candidates to replace PZT ceramics in high-temperature applications.