Structural distortion, piezoelectric properties, and electric resistivity of A-site substituted Bi_3TiNbO_9-based high-temperature piezoceramics

摘要

High-temperature piezoceramics Bi3-xCexTiNbO9+delta (BCTN-100x, x=0, 0.02, 0.04, 0.06, 0.07, 0.08, 0.10) were prepared by a solid-state reaction method. The crystal structure, microstructure, dielectric behaviour, piezoelectricity, temperature stability and electrical conduction mechanisms of BCTN-100x ceramics were studied. All Ce-doped Bi3TiNBO9 ceramics had a single Aurivillius phase structure. Ce substitution influenced the crystal structure, leading to a high piezoelectric constant (d(33) = 17 pC/N) but decreasing the Curie temperature slightly (T-C = 883 degrees C). The resistivity of Ce-doped BTN ceramics increased by two orders of magnitude compared with that of the pure BTN. Furthermore, the dc and ac conduction mechanisms were studied, indicating that the conduction mechanism is closely related to temperature for dc and ac conduction behaviour. In addition, we analysed the dielectric relaxation processes and attributed them to the motion of oxygen vacancies, which deviates from the ideal Debye-model.