Ultrasonically Assisted Hydrothermal Method for Ferroelectric Material Synthesis

Abstract

The hydrothermal method enables the production of high-quality piezoelectric materials. In this study, we propose to irradiate the reaction solutions with ultrasonic power during the hydrothermal method to obtain a shorter reaction time and a smooth film surface. A high-pressure reaction container for the ultrasonic transducer was newly developed, and the ultrasonically-assisted hydrothermal method was examined by using this container. The effect of ultrasonic assist on the synthesis of lead-zirconate-titanate (PZT) thin films and (K,Na)NbO3 powders was verified. Thicker PZT film, thickness around 10 µm, could be obtained in one process, and (K,Na)NbO3 powder was synthesized in half the previous reaction time.

Thick KNbO₃ films deposited by ultrasonic-assisted hydrothermal method

“…Upon ultrasonic irradiation, cavitation is generated, which is effective for promoting the hydrothermal reaction [8]. So far, we have confirmed the effect of ultrasonic irradiation on increasing the thickness of PZT films [7,8], whose thickness was increased four times larger from 2.6 mm to 9.7 mm [8].…”

“…In this study, thick potassium niobate (KNbO 3 ) films were investigated, which are required for medical transducers and micro actuators. To fabricate such films, we introduced an ultrasonic-assisted hydrothermal method [7][8][9][10][11].…”

“…However, it has a long reaction time and repeated deposition has been required for thicker films [12,13]. To overcome this problem, we developed an ultrasonic-assisted hydrothermal method [7][8][9][10][11] to obtain thicker films. Upon ultrasonic irradiation, cavitation is generated, which is effective for promoting the hydrothermal reaction [8].…”

Ultrasonic-assisted hydrothermal deposition of ferroelectric PbZrO3 thin film on NiTi-based superelastic shape memory alloys

“…The main features are low reaction temperatures below the Curie temperature, no need for post-treatment (polarization or annealing), and deposition on arbitrary shaped three-dimensional substrates. The ultrasonic-assisted hydrothermal deposition of piezoelectric thin film is performed using a ultrasonic transducer integrated in an autoclave [1,5,18]. Direct irradiation of ultrasound during hydrothermal synthesis improves the fabrication of fine particles.…”

Polycrystalline PZT film on porous Ti substrate synthesized by Ultrasonic Assisted Hydrothermal Method

“…We have proposed the ultrasonic irradiation of solutions to overcome these problems. [7] , [8] In this study, two topics are discussed, one is the optimum condition of ultrasonic irradiation for obtaining much thicker film and another is PZT deposition on porous Ti substrate.…”