Dielectric and piezoelectric properties of (Ba0.95Ca0.05)(Ti0.88Zr0.12)O3 ceramics sintered in a protective atmosphere

(Ba0.95Ca0.05)(Ti0.88Zr0.12)O3 (BCTZ) ceramics have been produced in a protective atmosphere of industrial N2 gas for potential piezoelectric applications. For comparison, the ceramics were also sintered at 1200–1400 °C in air. The results revealed that the reducing atmosphere of pO2 = 5 × 102 Pa had no substantial effect on the phase structure or the microstructure of the BCTZ ceramics. The XRD patterns suggested a tetragonal to pseudocubic phase transition at sintering temperatures above 1300 °C in both atmospheres. The nitrogen-sintered BCTZ samples had higher dielectric constants ɛr but lower electromechanical coupling coefficients kp than the air-sintered samples. The piezoelectric constant d33 for the BCTZ ceramics was not significantly influenced by the reducing atmosphere of pO2 = 5 × 102 Pa. The correlation of dielectric and piezoelectric properties of the BCTZ ceramics with the sintering temperature was explained based on a competing mechanism between phase structure and microstructure.