Texturing (Na0.5Bi0.5)TiO3-KNbO3-SrTiO3 Electrostrictive Ceramics by Templated Grain Growth Using (Na0.5Bi0.5)TiO3 Platelets

Electrostriction is an intriguing behaviour of dielectric materials, characterized by stable electrostrain with minimal hysteresis. (Na0.5Bi0.5)TiO3-based ceramics show promising electrostrictive behaviour, particularly the 0.90(Na0.5Bi0.5)TiO3-0.08KNbO3-0.02SrTiO3 composition located near the morphotropic phase boundary between ferroelectric rhombohedral and relaxor pseudocubic phases. The templated grain growth method has been effectively used to control the grain orientation of NBT-based systems, thereby enhancing their electrical properties. In this study, texturing was introduced to 0.90(Na0.5Bi0.5)TiO3-0.08KNbO3-0.02SrTiO3 ceramics through homoepitaxial NBT platelets prepared via a three-step molten salt/topochemical microcrystal conversion method. By adding 4 wt% of NBT platelets combined with optimized sintering conditions, textured ceramics were prepared exhibiting a high Lotgering factor of 83% with enhancement of strain (0.02%) and polarization (3 µC/cm2) at an electric field of 40 kV/cm, as well as stable dielectric permittivity between 130 and 300 °C. Moreover, the electrostrictive coefficient of textured ceramics increased by ~0.004 C2m−4 compared to that of untextured ceramics, confirming the improvement of the electrostrictive response. These results demonstrate that homoepitaxial templating effectively improves the electrical properties of NBT-KN-ST ceramics while preserving their electrostrictive nature, which offers a viable route for designing lead-free electrostrictive materials.