Effects of (Bi_(0.5)Na_(0.5))ZrO_3 addition on relaxation behavior and electrical properties of the KNN-LS ceramics

摘要

Abstract[0.94K0.48Na0.52Nb–(0.06−x)LiSbO3–xBi0.5Na0.5ZrO3, x = 0, 0.01, 0.02, 0.03, 0.04, 0.05] lead-free piezoelectric ceramics were prepared by a traditional two-step solid-state reaction method. The effects of BNZ addition on phase structure, electrical properties and dielectric relaxation of KNN–LS ceramics were investigated in this paper. X-ray diffraction patterns exhibit that the ceramics have a homogeneous perovskite structure with no other phases. (Bi0.5Na0.5)ZrO3doping can promote grain growth, increase density and enhance the electrical properties of the KNN–LS ceramics. When the addition amount (x) of BNZ is 0.04 mol, the ceramic exhibits optimum electrical properties: d33 = 286pC/N, Kp = 42%, εr = 2400, tanδ = 0.044. The dielectric constant and diffusive phase coefficient of the ceramics increase with the increase of BNZ. This indicates that the ceramics are with excellent relaxation behavior. When x is 0.01 mol, the dispersion coefficient γ reaches the maximum (1.55605) and the curie temperature of the ceramics is up to 350 °C. These results confirm that the ceramics are with the potentialities to be applied in the high temperature lead-free relaxor ferroelectrics.