Dielectric and piezoelectric properties of (Li, Ce) modified NaBi5Ti5O18 composite ceramics

Nominal (Li0.5Ce0.5)x(Na0.5Bi0.5)(1–x)Na0.5Bi4.5Ti5O18 composite ceramics were fabricated using conventional solid-state reaction method. The coexistence of bismuth layer-structured phase and perovskite phase was determined in these ceramics using XRD technique. At room temperature, the x=0.11 sample showed the largest piezoelectric constant, d33, of about 26.5 pC/N and the largest electromechanical coupling factor, kt, of about 30%. Even after annealing at 500 °C, the value of d33 was still about 19 pC/N, in x=0.08–0.11 samples. Moreover, these composite ceramics showed low temperature coefficients of dielectric constant and high electrical resistivity in the temperature region of 450–550 °C. These results indicated that (Li, Ce) modified NaBi5Ti5O18 composite ceramics were promising piezoelectric materials for high-temperature applications.