Effect of sintering temperature on the structure and properties of cerium-doped 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 piezoelectric ceramics

Phase structure, microstructure, dielectric and piezoelectric properties of 0.4 wt% CeO2 doped 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 (Ce-BNT6BT) ceramics sintered in the temperature range from 1120 to 1200 deg. C have been investigated as a candidate for lead-free piezoelectric ceramics. Tetragonal phase played an important role in improvement of electrical properties and the density of the ceramics. Dielectric constant decreased slightly with the increase of sintering temperature in ferroelectric region but a reverse phenomenon occurred in antiferroelectric and paraelectric regions, suggesting that interfacial polarizations were improved with the increase of sintering temperature and domain walls of ferroelectricity became active after depolarization. At room temperature, Ce-BNT6BT ceramics sintered at 1180 deg. C showed good performances: dielectric constant was 914 at 1 kHz, thick coupling factor kt was 0.52, and the ratio of kt/kp was 2.3. The ceramics were suitable for narrowband filters and ultrasonic transducers in commercial applications