Phase transitions, ferroelectric, and piezoelectric properties of lead-free piezoelectric xBaZrO3–(0.25−x)CaTiO3–0.75BaTiO3 ceramics

Lead-free xBaZrO3–(0.25−x)CaTiO3–0.75BaTiO3; x = 0.00–0.25 ceramics were successfully prepared using the conventional solid-state reaction method. Analysis of the sintered ceramics showed that all compositions exhibited a pure phase perovskite. The effects of composition on the phase transition, ferroelectric properties, and piezoelectric properties were studied. With the increasing BaZrO3 content, the phase transition temperature (TC) decreased and the coercive field Ec decreased. The phase diagram featuring a cubic–rhombohedral–tetragonal triple point (x ~ 0.125) was derived from X-ray diffraction data and dielectric data as a function of temperature. Compositions near the convergence region exhibited the maximum peak in permittivity of ~11,400 at TC. In addition, the morphotropic phase boundary compositions showed an enhancement in ferroelectric and piezoelectric properties. The composition 0.125BaZrO3–0.125CaTiO3–0.75BaTiO3 exhibited the highest strain values of 0.14 % and a d33^* of 474 pm/V.