LAUSR

ABSTRACT Lead-free ferroelectric ceramic, 0.70Bi0.5Na0.5TiO3-0.20Bi0.5K0.5TiO3- 0.10BaZr0.05Ti0.95O3 (BNT-BKT-BZT) was prepared by the solid-state reaction method. The powders were separately calcined at 850 °C/2 h for BNT, 850 °C/2 h for BKT and 1350°C/2 h for BZT, respectively. The crystal structure of BNT-BKT-BZT was characterized by X-ray diffraction (XRD) and refined by Rietveld refinement using FullProf program. The results indicated that a coexistence of rhombohedral (R) and tetragonal (T) phases occurs in the system, which tends to evolve into a tetragonal symmetry. The microstructure of each sample was investigated using scanning electron microscopy (SEM). The average grain size of BNT-BKT-BZT ceramics increased with the increasing sintering temperatures. The maximum dielectric constant (ϵSA = 5151), lowest dielectric loss (tanδ = 0.03) and the maximum piezoelectric coefficient (d33 = 206 pC/N) were obtained from the sample sintered at 1150°C.