Regulation of BaTiO3 ceramics' electrical properties by varying Na0.5Bi0.5TiO3 dopants

The piezoelectricity of BaTiO3 (BT) ceramics could be effectively regulated by Na0.5Bi0.5TiO3 (NBT) compounds, and the mechanism is still controversial. In this work, BT-xNBT ceramics with various NBT contents (x) were synthesized by a conventional solid-state sintering process. The characteristic of phase, cross-section morphology, permittivity, ferroelectricity, and piezoelectricity were fully explored by some advanced test equipment. With an increment of x, the ceramics possessed a high densification with a sole tetragonal phase, the diffused phase transition and relaxor ferroelectricity enhanced firstly and then receded. The inherent ferroelectricity and large strain of NBT materials under an electric field were deemed as the reasons for the increased ferroelectricity and piezoelectric coefficients with excessive x, respectively. Moreover, influences of impurity phases, fine grains, internal stress, etc. on the electrical properties were also discussed. This work provides a novel strategy to regulate BT-based lead-free piezoelectric ceramics.