Microstructure and electrical properties of relaxor (1 - x)[(K_(0.5)Na_(0.5))_(0.95)Li_(0.05)](Nb_(0.95)Sb_(0.05))O_(3-x)BaTiO_3 piezoelectric ceramics

摘要

In order to solve the low temperature stability of electrical properties in KNN-based ceramics, (1 - x)[(K_(0.5)Na_(0.5))_(0.95)Li_(0.05)](Nb_(0.95)Sb_(0.05))O_(3-x)BaTiO_3 [(1 - x)KNLNS-xBT] lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. The introduction of BT stabilizes the tetragonal phase of KNLNS ceramics at room temperature, results in a typical ferroelectric relaxor behavior, and shifts the polymorphic phase transition to below room temperature. Moreover, there is a strong BaTiO_3 concentration dependence of relaxor behavior and electrical properties, and the ceramic with x = 0.005 exhibits optimum electrical properties and typical relaxor behavior (d_(33) = 269 pC/N, k_p = 0.50, ?_r = 1371, tan ? = 0.03, T_C ~ 349 °C and ? = 1.88024). These results indicate that the BT is an effective way to improve the temperature stability as well as the electrical properties of KNN-based ceramics.