Piezoelectric and dielectric properties of PbNb2O6-based piezoelectric ceramics with high Curie temperature

Ferroelectric materials with high Curie temperature (higher than 300 °C) are highly desirable to construct transducers for high-temperature piezoelectric applications. Among the ferroelectric materials, PbNb2O6 (PN) is considered to be one of the most promising materials. However, the fabrication of high density PN ceramics is very difficult, which limited the use in piezoelectric transducers. In this study, high density (∼95%) Ca- and excess Ti-doped PN ceramics were prepared through the conventional ceramic method. The electromechanical and dielectric properties as well as Curie temperature were measured. The properties of pure PN were comparable to those observed in Ca- and Ti-modified PN ceramics. The results reveal that the addition of Ca and excess Ti increase the Curie temperature and the density of the PN ceramics, but slightly decrease the piezoelectric properties. This Ca- and Ti-doped PN ceramics present a high potential to be used in high-temperature applications as piezoelectric transducers.