Cylindrically shaped ultrasonic linear array fabricated using PIMNT/epoxy 1-3 piezoelectric composite

Luo

2017

Crystals

Self Cite

Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PIN-PMN-PT) piezoelectric single-crystal rectangular beams with the PIN:PMN:PT ratio of 0.33:0.35:0.32 are prepared, and their mode-coupling effect is investigated both theoretically and experimentally for ultrasonic array transducer applications. The PIN-PMN-PT rectangular beams become a tall-narrow beam and a short-wide plate, and so exhibiting an uncoupled height-extensional (beam) mode and an uncoupled thickness-extensional (plate) mode, at a width-to-height ratio G (= L/H) of <0.7 and >6.0, respectively. With G varying in the range of 1.6 to 3.1, the beam mode not only couples strongly with the width (lateral) mode, but also coexists obviously with the plate mode, giving high electromechanical coupling coefficients k' 33 and k t of~0.75 and~0.50, respectively. With the guide of the mode-coupling results, a multifrequency ultrasonic array transducer having three distinct operational frequencies of 1.52, 2.60, and 6.01 MHz, corresponding to the coupled/coexistent beam mode, lateral mode, and plate mode, respectively, is developed using a mode-coupled rectangular beam of G = 1.6. Two different single-frequency ultrasonic array transducers, fabricated using two different uncoupled rectangular beams, one operating in uncoupled beam mode with G = 0.6 at 2.24 MHz and one working in uncoupled plate mode with G = 10.0 at 5.75 MHz, are also developed for comparison.

Section: Introductionmentioning

confidence: 99%

Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 Piezoelectric Single-Crystal Rectangular Beams: Mode-Coupling Effect and Its Application to Ultrasonic Array Transducers

Luo

2017

Crystals

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“…PMNT single crystals and their composites have been applied in the field of NDT over the past several years, such as dual element transducer and angle beam transducer [8,9,10,11,12], while they were limited to some low-frequency range of NDT applications. In this work, 5–6 MHz PMNT/epoxy 1–3 composites were prepared by a modified dice-and-fill technology.…”

Section: Introductionmentioning

confidence: 99%

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

Deng

et al. 2015

Sensors

Self Cite

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.

“…Traditionally [9,10], lead zirconate titanate (PZT) ceramics are the most popular piezoelectric materials used in the fabrication of ultrasonic transducers because of their high performance and ease of manufacturing [11–14]. Relaxor-PbTiO 3 (PT) based ferroelectric single crystals near the morphotropic phase boundary (MPB) have been widely researched during the last decades due to their significantly high electromechanical coupling coefficients ( k t ∼ 60%), extremely large strains (>1%) and extremely high piezoelectric coefficients ( d 33 > 2000 pC/N) compared with PZT-based piezoceramics (strain ∼ 0.1%, k t ∼ 48%, d 33 ∼ 400–600 pC/N) [15–17]. …”

Section: Introductionmentioning

confidence: 99%

Fabrication of a PMN-PT Single Crystal-Based Transcranial Doppler Transducer and the Power Regulation of Its Detection System

et al. 2014

Sensors

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Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The −6 dB bandwidth of the transducer is 68.4% and the sensitivity is −17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries.