Crystal Structure, Piezoelectric and Dielectric Properties of (Li, Ce)4+, Nb5+ and Mn2+ Co-doped CaBi4Ti4O15 High-Temperature Ceramics

Bismuth-layered structured ceramics Ca-0.85(Li,Ce)(0.075)Bi4Ti4-x Nb (x) O-15-0.01MnCO(3) were prepared by the conventional solid-state reaction method. The evolution of microstructure and corresponding electrical properties were studied. All the samples presented a single bismuth layered-structural phase with m = 4, indicating that (Li, Ce)(4+), Nb5+ and Mn2+ adequately enter into the pseudo-perovskite structure and form solid solutions. It was found that Ca-0.85(Li,Ce)(0.075)Bi4Ti3.98Nb0.02O15-0.01MnCO(3) (CBTLCM-0.02Nb) ceramics possess the optimum electrical properties. The piezoelectric coefficient d (33), dielectric constant epsilon (r), loss tan delta, planar electromechanical coupling factor k (p) and Curie-temperature T (C) of CBTLCM-0.02Nb ceramics were found to be similar to 19.6 pC/N, 160, 0.16%, 8.1% and 767A degrees C, respectively. Furthermore, the thermal depoling behavior demonstrates that the d (33) value of x = 0.02 content remains at 16.8 pC/N after annealing at 500A degrees C. These results suggest that the (Li, Ce)(4+)-, Nb5+- and Mn2+-doped CBT-based ceramics are promising candidates for high-temperature piezoelectric applications.