Piezoelectric Materials Synthesized by the Hydrothermal Method and Their Applications

Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate (PZT) thin film was applied to a micro ultrasonic motor, and an epitaxial lead titanate (PbTiO(3)) thin film was estimated as a ferroelectric data storage medium. Ferroelectric and piezoelectric properties were successfully obtained for epitaxial PbTiO(3) films. As lead-free piezoelectric powders, KNbO(3) and NaNbO(3) powders were synthesized by the hydrothermal method and sintered together to form (K,Na)NbO(3) ceramics, from which reasonable piezoelectric performance was achieved.