The effects of CeO_2-doping on piezoelectric and dielectric properties of Bi_(0.5)(Na_(1-x-y)K_xLi_y)_(0.5)TiO_3 piezoelectric ceramics

摘要

CeO_2-doped Bi_(0.5)(Na_(1-x-y)K_xLi_y)_(0.5)TiO_3 lead-free piezoelectric ceramics were prepared by solid-state reaction processes. X-ray diffraction (XRD) data show that the ceramics possess pure perovskite phase. SEM images indicate that a small amount of CeO_2 affects the microstructure. The electrical properties of Bi_(0.5)(Na_(0.725)K_(0.175)Li_(0.1))_(0.5)TiO_3 ceramics have been greatly improved by doping of certain amount of CeO_2. The temperature dependence of the dielectric constant and dissipation factor reveals that the transition temperature from ferroelectric to anti-ferroelectric phases (T_f) decreases with the addition of CeO_2. At room temperature, the ceramics doped with 0.1 wt% CeO_2 show quite good performance with high piezoelectric constant (d_(33) = 220 pC/N), high coupling factor (k_p = 39.3%,), enhanced dielectric constant (ε_r = 897) and low dissipation factor (tan δ = 2.0%) at 1 kHz, which indicates that CeO_2-doping possesses both effects of increasing the piezoelectric properties and decreasing the dissipation factor of the ceramics.