Broadband and High Sensitive Time-of-Flight Diffraction Ultrasonic Transducers Based on PMNT/Epoxy 1–3 Piezoelectric Composite

Abstract

5–6 MHz PMNT/epoxy 1–3 composites were prepared by a modified dice-and-fill method. They exhibit excellent properties for ultrasonic transducer applications, such as ultrahigh thickness electromechanical coupling coefficient kt (85.7%), large piezoelectric coefficient d33 (1209 pC/N), and relatively low acoustic impedance Z (1.82 × 107 kg/(m2·s)). Besides, two types of Time-of-Flight Diffraction (TOFD) ultrasonic transducers have been designed, fabricated, and characterized, which have different matching layer schemes with the acoustic impedance of 4.8 and 5.7 × 106 kg/(m2·s), respectively. In the detection on a backwall of 12.7 mm polystyrene, the former exhibits higher detectivity, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −21.93 dB and 102.7%, respectively, while the later exhibits broader bandwidth, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −24.08 dB and 117.3%, respectively. These TOFD ultrasonic transducers based on PMNT/epoxy 1–3 composite exhibit considerably improved performance over the commercial PZT/epoxy 1–3 composite TOFD ultrasonic transducer.

High-Performance Curved Piezoelectric Single-Crystal Composites via 3D-Printing-Assisted Dice and Insert Technology for Underwater Acoustic Transducer Applications

“…Temperature dependence of the (e) conductance spectrum, (f) resonance frequency f r , antiresonance frequency f a and thickness electromechanical factor k t of 1–3 PINMT PSCC. (g) Comparison of d 33 and k t with previously reported PCCs and PSCCs. ,,,− (h) Comparison of d 33 and the piezoelectric phase volume fraction with other reported PCCs and PSCCs. ,,− ,,− …”

“…The longitudinal piezoelectric coefficient d 33 and thickness electromechanical factor k t are the two main parameters for evaluating the performance of piezoelectric materials for UATs. As indicated in Figure g, the PSCCs, in general, show better piezoelectric and electromechanical performance than PCCs owing to the better performance of single crystals than ceramics. ,,,− Compared to other PSCCs, the 1–3 PSCC with high d 33 and k t was achieved. According to the simulation and experimental studies of previous papers, , the aspect ratio is usually designed to be <0.4, so that the transducer can resonate in a nearly pure mode, further yielding the maximum k t .…”

“…In recent years, Pb-based relaxor piezoelectric single crystals with high electromechanical coupling factors and piezoelectric coefficients have shown great potential for further improving the properties of PCs. − Several studies have shown that piezoelectric single-crystal composites (PSCCs) exhibit better performance than PCCs, which dramatically increases the resolution of imaging applications in ultrasonic transducer fields. For the same reason, PSCCs have also attracted extensive attention for UAT applications. − In addition, in order to achieve large detection coverage and higher source level that the planar PC acoustic transducers cannot satisfy, various curve-shaped PCs have been designed and fabricated, such as arc, cylinder, double curved, etc. However, different from ultrasonic transducers, UATs usually require PSCCs to have a high thickness (>2 mm) because of their low operating frequency (<700 kHz), which brings about a new challenge of preparing PSCCs due to the fragile characteristics and anisotropy of single crystals, especially for curve-shaped PSCCs.…”

Edge geometry effects on resonance response of electroplated cylindrical Ni/PZT/Ni magnetoelectric composites

“…17 It was calculated that Q m = 173 for the sample with edges, Q m = 232.7 for the sample with no outer edges and Q m = 247.4 for the sample with no outer and inner edges in the vertical mode.…”

A Seismic Data Acquisition System Based on Wireless Network Transmission

“…The outstanding performance of PMN-PT makes it an ideal functional material for high sensitivity and low noise sensors. PMN-PT has been preliminarily used in ultrasonic motors [ 21 ], piezoelectric transformers [ 22 ], magnetoelectric sensors [ 23 ], and ultrasonic transducers [ 24 ]. These devices have a superior performance to those made with PZT, which shows promising applications in device fabrications.…”