Ultrasonic Transducer for the Hydrothermal Method

Abstract

Direct ultrasound irradiation is advantageous for increasing the efficiency of the hydrothermal method, which can be used to produce piezoelectric thin films and lead-free piezoelectric ceramics. To apply ultrasound directly to the process, transducer prototypes were developed regarding the boundary conditions of the hydrothermal method. LiNbO3 and PIC 181 were proven to be feasible materials for high-temperature-resistant transducers (≥200 • C). The resistance of the transducer's horn against a corrosive mineralizer was achieved by using Hastelloy C-22. The efficiency of the ultrasound-assisted hydrothermal method depends on the generated sound field.The impedance and the sound field measurements have shown that the sound field depends on the filling level and on the position and design of the transducer.

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

“…1. [7], [10] This autoclave enables us to irradiate ultrasound into the chemical solution directly and it is considered to accelerate the chemical reaction due to cavitation and acoustic streaming. [II] The condition of ultrasonic transducer and starting materials are respectively shown in Table 1 and 2.…”

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.…”

Thick KNbO₃ films deposited by ultrasonic-assisted hydrothermal method

“…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].…”