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

Sensors

Dongxu Liu¹  Qingwen Yue¹  Ji Deng¹  Di Lin¹  Xiaobing Li¹  Wenning Di¹  Xi𠆚n Wang¹  Xiangyong Zhao¹  Haosu Luo¹ 

[1] Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, University of Chinese Academy of Sciences, 215 Chengbei Road, Jiading, Shanghai 201800, China; E-Mails:

关键词: time-of-flight diffraction;    ultrasonic transducer;    PMNT;    1–3 piezoelectric composite;   

DOI  :  10.3390/s150306807

来源: mdpi

【 摘 要 】

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 k_t (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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.