Performance of relaxor ferroelectric single crystal transducer under high hydrostatic pressure

In this paper, we investigate the performance and pressure stability of the relaxor ferroelectric single crystal transducer under high hydrostatic pressure. First, the short pulse signal is used to measure the admittance of the transducer in a high-pressure tank, and the minimum frequency that can be measured in a pressure tank is calculated. Then we design a high-frequency three-layer transducer made of the relaxor ferroelectric single crystal and utilize the finite element method to calculate its performance such as the admittance, transmitting voltage response (TVR), directivity, etc. Finally, we manufacture the single crystal three-layer transducer, and carry out the experimental verification in an anechoic water tank and a high-pressure tank. The experimental result in an anechoic water tank shows that the TVR in the 20-36 kHz region is higher than 137 dB, and the maximum TVR is 145.5 dB at 34 kHz. The experimental result in a high-pressure tank shows that the conductance at the resonant frequency will gradually decrease with the increase of water pressure, and is reduced by about 14% at 50 MPa compared with that at normal pressure. Besides, the radius of the admittance circle also decreases under high hydrostatic pressure, whereas the resonant frequency changes little, and the quality of the transmitted waveforms received by the hydrophone is good. We can conclude that the performance of the relaxor ferroelectric single crystal transducer is still stable under high hydrostatic pressure, thus allowing various applications in the deep sea.