Morphotropic phase boundary and electrical properties in $(1−x)Bi0.5Na0.5TiO3−xBi(Zn0.5Ti0.5)O3$ lead-free piezoceramics

$(1−x)Bi0.5Na0.5TiO3−xBi(Zn0.5Ti0.5)O3$ [$(1−x)BNT−xBZT$⁠, $x=0$⁠, 0.025, 0.0375, 0.050, and 0.075] lead-free piezoceramics were prepared and their structures and electrical properties were investigated. It is found that BZT can increase the Curie temperature of BNT. A morphotropic phase boundary (MPB) separating rhombohedral and tetragonal phases exists near $x=0.0375$⁠. As the result, the MPB composition shows improved electrical properties; the saturated polarization, remnant polarization, and coercive field are $42.0μC/cm2$⁠, $36.5μC/cm2$⁠, and 3.5 kV/mm, respectively, while the piezoelectric coefficient, planar electromechanical coupling factor, and unipolar strain are 92 pC/N, 0.22, and 0.08%, respectively. The structures and electrical properties are discussed by comparing with that of other BNT-based piezoceramics. Our results do not only supplement for BNT-based lead-free piezoceramics, but also may provide a way to develop new lead-free piezoceramics with high Curie temperature.