Fabrication and performance of a single-crystal lead magnesium niobate-lead titanate cylindrical hydrophone

Abstract

The development of a piezoelectric hydrophone based on lead magnesium niobate-lead titanate [PbMg1/3Nb2/3O3-PbTiO3 (PMN-PT)] single-crystal piezoelectric as the hydrophone substrate is reported. Although PMN-PT can possess much higher piezoelectric sensitivity than traditional lead zirconate titanate (PZT) piezoelectrics, it is highly anisotropic and therefore there is a large gain in sensitivity only when the crystal structure is oriented in a specific direction. Because of this, simply replacing the PZT substrate with a PMN-PT cylinder is not an optimal solution because the crystal orientation does not uniformly align with the circumferential axis of the hydrophone. Therefore, a composite hydrophone that maintains the optimal crystal axis around the hydrophone circumference has been developed. An 11.3 mm diameter composite hydrophone cylinder was fabricated from a single <110> cut PMN-PT rectangular plate. Solid end caps were applied to the cylinder and the sensitivity was directly compared with a solid PZT-5A cylindrical hydrophone of equal dimensions in a hydrophone test tank. The charge sensitivity showed a 9.1 dB improvement over the PZT hydrophone and the voltage sensitivity showed a 3.5 dB improvement. This was in good agreement with the expected theoretical improvements of 10.1 and 4.5 dB, respectively.

Relaxor-PT Single Crystal Piezoelectric Sensors

“…The relative improvement in charge sensitivity, voltage sensitivity, and figure of merit (FOM) of the PMN-PT based hydrophone was ~9.1 dB, ~3.5 dB, and 6.3 dB higher than those of the PZT-5A hydrophone, respectively. The size of the PMN-PT hydrophone can be reduced by half of the PZT-5A hydrophone due to its high sensitivity [74]. This result showed a promising point that a certain combination between various crystal cut orientation and suitable design for the sensing mode can improve the performance or reduce the size of hydrophones.…”

“…For underwater detection, the towed array sonar system (TASS) composed of small piezoelectric hydrophones in linear arrangement have become popular [74]. Although the development of fast and versatile signal processing algorithms is important to improve the performance of hydrophone systems, stable pressure sensing with high sensitivity by hydrophone elements is the most important factor for underwater applications [75].…”

“…Recently, Brown et al [74] developed a cylinder-shaped composite hydrophone that operates in radial vibration mode. Instead of a conventional single ring structure, multiple long strip crystal elements were configured to encircle a cylinder (Figure 4b).…”

“…The schematic illustration of fabrication process is shown in Figure 4a. Reprinted with permission from [74]. copyright 2013 Acoustical Society of America.…”

3D printed interactive speakers

“…Stretchable speakers use silicon substrates and ionic conductors to produce audible sound [11]. Cylindrical speakers create omnidirectional sound by using PZT tubes [12] or arrays of transducers placed on cylindrical surfaces [1,24].…”