(Na_0.52K_0.44Li_0.04)Nb_0.9-xSb_xTa_0.1O₃ Lead-Free Piezoelectric Ceramics with High Performance and High Curie Temperature

(Na_0.52K_0.44Li_0.04)Nb_0.9-xSb_xTa_0.1O₃ lead-free piezoelectric ceramics are prepared by a solid-state reaction method. With increasing Sb content, the transition temperature from orthorhombic to tetragonal polymorphic phase decreased. A composition (Na_0.52K_0.44Li_0.04)Nb_0.863Sb_0.037Ta_0.1O₃ is found to possess excellent piezoelectric and electromechanical performances (d₃₃=306pC/N, k_p=48%, and k_t=50%), and high Curie temperature (T_C=320°C). These results indicate that (Na_0.52K_0.44Li_0.04)Nb_0.863Sb_0.037Ta_0.1O₃ is a promising lead-free piezoceramics replacement for lead zirconate titanate.