Structure and properties of hot-pressed lead-free (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 piezoelectric ceramics
Randomly-oriented and textured (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics are prepared by a hot-pressing (HP) method. The phase structure, microstructure, and electrical properties are systematically investigated. Structural analysis shows a decrease in tetragonality of the hot-pressed samples. The orientation of the as-processed ceramics is studied by X-ray diffraction and electron backscatter diffraction, revealing an increase in texture of the hot-pressed textured BCZT ceramics. Microstructure characterization demonstrates that the hot-pressing can greatly improve the densification of the BCZT ceramics. Dielectric constant measurement obeys a modified Curie–Weiss law. The relaxor-like behavior is decreased in hot-pressed samples. The Curie temperatures of the hot-pressed BCZT (BCZT-HP) and the hot-pressed BCZT with texture templates (BCZT-T-HP) ceramics are greatly increased to 76 °C and 90 °C, respectively. The optimum piezoelectric properties for the BCZT-HP and BCZT-T-HP ceramics are d33 = 510 pC N−1, kp = 44%, d31 = −182 pC N−1, k31 = 23% and d33 = 580 pC N−1, kp = 49%, d31 = −204 pC N−1, k31 = 31%, respectively. Therefore, the BCZT-HP and BCZT-T-HP ceramics are promising lead-free piezoelectric ceramics which can be used in higher temperature than their counterparts prepared by conventional sintering.