The effects of oxygen vacancies on the electrical properties of W, Ti doped CaBi2Nb2O9 piezoceramics

Different type doped CaBi2Nb2O9 (CBN) ceramics were prepared by a conventional solid state sintering method. The number of oxygen vacancies were decreased or increased by the introduction of W6+ and Ti4+ doping in CBN ceramics. The influence of W6+, Ti4+ and W6+/Ti4+ dopants on the microstructures and electrical properties of CBN-based ceramics was investigated. The voids and spherical morphology in the SEM image of W, Ti co-doped ceramics indicate that W, Ti co-doping could change the microstructure of CBN-based ceramics. Impedance analysis results show that the electrical properties of CBN-based ceramics have a close relationship with the number of oxygen vacancies. W doping and W, Ti co-doping decrease the oxygen vacancies, as a result, the resistance and piezoelectric properties were increased and the frequency dispersion of dielectric properties were restrained.