Dielectric and piezoelectric properties of (1 2 x)(Na0.5K0.5) NbO3–xBaTiO3 ceramics

This manuscript reviews the studies on phase transitions, synthesis, and piezoelectric/dielectric properties of (1 - x)(Na0.5K0.5)NbO3–xBaTiO3 ceramics (0.0 B x B 1.0). Three phase transition regions were observed in (1 - x)(Na0.5K0.5)NbO3–xBaTiO3 ceramics corresponding to orthorhombic, tetragonal, and cubic phases. The composition 0.95(Na0.5K0.5)NbO3–0.05BaTiO3, which lies on the boundary of orthorhombic and tetragonal phases, was found to exhibit excellent piezoelectric properties. The properties of this composition were further improved by addition of various additives making it suitable for multilayer actuator application. The composition 0.06(Na0.5K0.5)NbO3–0.94 BaTiO3 was found to lie on the boundary of tetragonal and cubic phases. This composition exhibited the microstructure with small grain size and excellent dielectric properties suitable for multilayer ceramic capacitor application. Based on the studies reported in literature, we expect the modified (1 - x)(Na0.5K0.5)NbO3–xBaTiO3 system to become the leading lead-free candidate for piezoelectric and dielectric components.