Cooling rate-dependent microstructure and electrical properties of BCZT ceramics

Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) ceramics were successfully synthesized by controlling the cooling rate during the sintering, and their microstructure and electrical properties were systematically analyzed. The results indicate that all BCZT ceramics show the coexistence of orthorhombic (O) and tetragonal (T) phases near room temperature. As a result of the interaction of grain size and densification , the remnant polarization, dielectric constant, and piezoelectric constant increase firstly and then decrease with the rise of cooling rate. The piezoelectric responses of BCZT ceramics are improved by optimizing the cooling process. BCZT ceramics prepared by the cooling rate with 4 °C/min have high dielectric constant ( ε m  = 23879), high remnant polarization (2 P r  = 30.26 μC/cm 2 ), and excellent piezoelectric responses ( d 33  = 551.1 pC/N and d 33 * = 630 pm/V), which is due to the coexistence of O-T phase, larger grain size, and superior densification. These findings demonstrate that excellent piezoelectric properties for BCZT ceramics can be achieved by optimizing the cooling rate during the sintering process .