Piezoelectric and dielectric properties of CeO2-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free ceramics

CeO2-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free piezoelectric ceramics (0-1.0 wt.%) were synthesized by conventional solid-state processes. X-ray diffraction (XRD) data shows that CeO2 diffuses into the lattice of (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics and forms pure perovskite phase. SEM images indicate that a small amount of CeO2 addition affects the microstructure. The electrical properties of (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics have been greatly improved by a certain amount of CeO2 addition. The temperature dependence of the dielectric constant and dissipation factor shows that the transition temperature from ferroelectric to antiferroelectric phase (Td) decreases with the addition of CeO2. At the room temperature, the ceramics doped with 0.4 wt.% CeO2 show quite good performance with high piezoelectric constant (d33 = 128 pC/N), high planar coupling factor (kp = 0.283), high mechanical quality factor (Qm = 216), high thick coupling factor (kt = 0.54), high dielectric constant (r = 891) and low dissipation factor (tan delta = 0.0185) at 1 kHz, which indicates that CeO2-doped sample is of high piezoelectric properties and low dissipation factor. Possible mechanism of the influence of CeO2 addition on the dielectric and piezoelectric properties is discussed.