Structure, piezoelectric, dielectric and ferroelectric properties of lead-free (1-x)(Ba0.85Ca0.15)(Ti0.93Zr0.07)O3-x(Bi0.5K0.5)TiO3 ceramics

Lead free solid solution ceramics (1-x)(Ba0.85Ca0.15)(Ti0.93Zr0.07)O-3-x(Bi0.5K0.5)TiO3 [(1-x) BCZT-xBKT, x = 0, 0.02, 0.04, 0.06, 0.08 mol%] were fabricated by the traditional solid-state reaction technique. The crystalline phase was confirmed by X-ray diffraction (XRD) patterns and Raman spectra, the results show that a pure ABO(3) perovskite structure was obtained in all of these samples, suggesting that BKT diffused into BCZT to form a solid solution. The microstructure and crystal structure were investigated by thermal field emission scanning electron microscopy (TFESEM) and field emission transmission electron microscopy (FETEM) respectively. The results show that all of these samples exhibited relatively higher density structure. Monocrystal and polycrystal coexistence structure was obtained in BKT doped ceramics at room temperature. In addition, the piezoelectric, dielectric and ferroelectric properties were systematically studied. The ceramic with x = 0.04 mol% BKT demonstrates good properties: d(33) = 162 pC/N, T-c = 103.1 degrees C, k(p) = 46.2%, epsilon(r) = 2,390, tan delta = 1.5%, P-r = 9.33 mu C/cm(2), E-c = 0.80 kV/mm. (C) 2017 Elsevier B.V. All rights reserved.