Influence of Bi4Ti3O12 doping on structural and piezoelectric properties of (K0.4425Na0.52Li0.0375)(Nb0.87Ta0.06Sb0.07)O3 lead-free ceramics

Recently, (K, Na, Li)(Nb, Ta, Sb)O3 ceramics have attracted much attention of researchers, and have become one of the most popular systems of KNN-based ceramics. In this paper, Bi4Ti3O12 was added in the (K0.4425Na0.52Li0.0375)(Nb0.87Ta0.06Sb0.07)O3 ceramics (KNLNTS-x mol% BIT) to improve their piezoelectric properties. The phase formation and microstructure of KNLNTS-x mol% BIT ceramics were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). With the addition of BIT, the permittivity maxima of samples shifted toward higher temperature firstly and then shifted to lower temperature. All samples showed well ferroelectric behavior and the density of (1-x)KNLNTS-x mol% BIT ceramics were increased and reached a relative density of 99.4%. High piezoelectric properties of d33 = 255 pC/N, kp = 0.451, Qm = 186 were obtained for the samples containing 0.50 mol% BIT.