(K_0.5Na_0.5)_0.96Li_0.04Nb_0.86Ta_0.1Sb_0.04O₃–SrZrO₃ ceramics with good fatigue-resistance and temperature-stable piezoelectric properties

(1 − x)(K_0.5Na_0.5)_0.96Li_0.04Nb_0.86Ta_0.1Sb_0.04O₃–xSrZrO₃ (KNLNST–xSZ) (x = 0.000, 0.005, 0.010 and 0.015) lead-free ceramics were prepared by conventional solid-state sintering method. Crystal structure was determined using X-ray diffraction. The microstructure of the ceramics was observed by field emission electron microscope. The ceramics possessed a tetragonal perovsktie structure at room temperature without impurity phase. The average grain size was found to increase with increasing SZ. Meanwhile, the grain size distribution became much broader. According to the impedance analysis, the movements of oxygen vacancies played an important role in the conduction behavior at higher temperatures. The γ value increased from 1.18 for x = 0.000 to 1.31 for x = 0.010, implying that the characteristics of KNLNST–xSZ ceramics transferred from ferroelectric to more relaxor-like with increasing SZ content. Accordingly, the temperature stability and fatigue behavior of the modified ceramics were significantly improved, demonstrating that these materials had excellent potential for demanding high cycle and high temperature applications.