LAUSR

Abstract The piezoelectric properties of lead-free Ba0.88Ca0.12Zr0.12Ti0.88O3 (BCZT) ceramics were greatly optimized by doping Co ions using a CoO powder. The role of Co2+ and Co3+ in enhancing the piezoelectric properties and the relationship between the content ratio Co3+/Co2+ and piezoelectric performance were studied. The X-ray diffraction patterns of all samples indicated that crystalline phases were a BCZT-based single perovskite structure regardless of the Co ion content. The phase transition temperature and lattice distortion degree were related to the Co ion content and the content ratio Co3+/Co2+ because Co2+ resulted in higher oxygen vacancy generation, whereas Co3+ induced larger lattice shrinkage. The ceramic containing 0.10 wt% of Co ion showed the best piezoelectric and dielectric performance with the highest piezoelectric constant d33 ~ 490 p.m./V at room temperature and the highest Curie temperature Tc of 110 °C, which increased by 29% and 16%, respectively. In this case, the content ratio Co3+/Co2+ reached the maximum value of 0.86. The high piezoelectric properties and phase stability of BCZT ceramics by doping Co ions make these ceramics promising piezoelectric materials for practical applications.