Texturing (Na_0.5Bi_0.5)TiO₃-KNbO₃-SrTiO₃ Electrostrictive Ceramics by Templated Grain Growth Using (Na_0.5Bi_0.5)TiO₃ Platelets

Electrostriction is an intriguing behaviour of dielectric materials, characterized by stable electrostrain with minimal hysteresis. (Na_0.5Bi_0.5)TiO₃-based ceramics show promising electrostrictive behaviour, particularly the 0.90(Na_0.5Bi_0.5)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(Na_0.5Bi_0.5)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.