Perovskite (Na_(0.5)K_(0.5))_(1-x)(LiSb)_xNb_(1-x)O_3 lead-free piezoceramics

摘要

Lead-free potassium sodium niobate piezoelectric ceramics substituted with lithium and antimony (Na_(0.5)K_(0.5))_(1-x)(LiSb)_xNb_(1-x)O_3 have been synthesized by conventional solid state sintering method. Compositionally engineered around the orthorhombic-tetragonal polymorphic phase transition, the dielectric and piezoelectric properties were further enhanced with the addition of lithium and antimony substituted into the perovskite structure. The combined effects of lithium and antimony additions resulted in a downward shift in the orthorhombic-tetragonal (T_(O-T)) without significantly reducing T_C. The dielectric, piezoelectric, and electromechanical properties were found to be ε/ε_0 > 1300, d_(33) > 260 pC/N, and k_p > 50%, while maintaining low dielectric loss. The enhanced polarizability associated with the polymorphic T_(O-T) transition and high T_C transition (～390℃) should provide a wide range of temperature operation.