Influence of BiFeO 3 doping on structural and electrical properties of KNN–LS based lead-free piezoceramics

(0.94 − x)K0.48Na0.52NbO3–0.06LiSbO3–xBiFeO3 (KNN–LS–xBF, x = 0, 0.1, 0.3, 0.5 and 0.7%) lead- free piezoelectric ceramics were prepared by a traditional two-step solid-state reaction method. The effect of BiFeO3 (BF) content on the phase structure, microstructure, electrical properties and dielectric relaxation of KNN–LS ceramics was investigated. The XRD patterns show that all ceramics have a pure perovskite structure. BiFeO3 doping can promote the grain growth and improve electrical properties. When x = 0.3% in KNN–LS–BF, it exhibits optimum electrical performance: d33 = 285 pC/N, kp = 54.3%, er = 2185, tanδ = 1.92%, Qm = 66, Tc = 340 °C, γ = 1.4732, Ec = 17.76 kV/cm, Pr = 21.48 µC/cm2. It is indicated that the ceramics have the potentialities to be used as the high temperature low frequency filters.