Effect of direct current and alternating current poling on the piezoelectric properties of Ba0.85Ca0.15Ti0.9Zr0.1O3 ceramics

Lead-free piezoceramics are international research frontier in the fields of functional materials. In this work, high-quality Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZ) ceramics were prepared by using ultrafine powder synthesized by the molten salt method. The results show that the enhanced piezoelectric properties are obtained at intermediate grain size of 14.7 μm. Furthermore, by the optimization of the DC poling parameters, excellent d33 ~ 600 pC/N and kp ~ 0.50 values of BCTZ lead-free ceramic can be obtained, while d33 ~ 420 pC/N and kp ~ 0.35 were obtained under the optimal AC poling parameters. The property difference is mainly due to that AC poling does not give enough time for the internal stress to relax, allowing the switched ferroelastic domains to accommodate each other, so it is difficult to achieve saturated poling. Though, AC poling method still provides a new insight for the optimization of the performance of piezoelectric ceramics.