High Frequency Needle Ultrasonic Transducers Based on Lead-Free Co Doped Na0.5Bi4.5Ti₄O15 Piezo-Ceramics

Chunlong Fei; Tianlong Zhao; Danfeng Wang; Yi Quan; Pengfei Lin; Di Li; Yintang Yang; Jianzheng Cheng; Chunlei Wang; Chunming Wang; Qifa Zhou

doi:10.3390/mi9060291

High Frequency Needle Ultrasonic Transducers Based on Lead-Free Co Doped Na_0.5Bi_4.5Ti₄O₁₅ Piezo-Ceramics

Micromachines (Basel). 2018 Jun 10;9(6):291. doi: 10.3390/mi9060291.

Authors

Chunlong Fei¹, Tianlong Zhao², Danfeng Wang^{3

4}, Yi Quan⁵, Pengfei Lin⁶, Di Li⁷, Yintang Yang⁸, Jianzheng Cheng⁹, Chunlei Wang¹⁰, Chunming Wang¹¹, Qifa Zhou¹²

Affiliations

¹ School of Microelectronics, Xidian University, Xi'an 740071, China. clfei@xidian.edu.cn.
² School of Microelectronics, Xidian University, Xi'an 740071, China. zhaotl@xidian.edu.cn.
³ School of Microelectronics, Xidian University, Xi'an 740071, China. jikedandan@163.com.
⁴ School of Electronic and Electrical Engineering, Wuhan Textile University, Wuhan 430200, China. jikedandan@163.com.
⁵ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 740049, China. quanyi@stu.xjtu.edu.cn.
⁶ School of Microelectronics, Xidian University, Xi'an 740071, China. pflinxidian@163.com.
⁷ School of Microelectronics, Xidian University, Xi'an 740071, China. lidi2004@126.com.
⁸ School of Microelectronics, Xidian University, Xi'an 740071, China. yangyt@xidian.edu.cn.
⁹ School of Electronic and Electrical Engineering, Wuhan Textile University, Wuhan 430200, China. jzcheng@wtu.edu.cn.
¹⁰ School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. wangcl@sdu.edu.cn.
¹¹ School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. wangcm@sdu.edu.cn.
¹² Department of Ophthalmology and Biomedical Engineeing, University of Southern California, Los Angeles, CA 90089-1111, USA. qifazhou@usc.edu.

Abstract

This paper describes the design, fabrication, and characterization of tightly focused (ƒ-number close to 1) high frequency needle-type transducers based on lead-free Na_0.5Bi_4.5Ti_3.975Co_0.025O₁₅ (NBT-Co) piezo-ceramics. The NBT-Co ceramics, are fabricated through solid-state reactions, have a piezoelectric coefficient d₃₃ of 32 pC/N, and an electromechanical coupling factor k_t of 35.3%. The high Curie temperature (670 °C) indicates a wide working temperature range. Characterization results show a center frequency of 70.4 MHz and a -6 dB bandwidth of 52.7%. Lateral resolution of 29.8 μm was achieved by scanning a 10 μm tungsten wire target, and axial resolution of 20.8 μm was calculated from the full width at half maximum (FWHM) of the pulse length of the echo. This lead-free ultrasonic transducer has potential applications in high resolution biological imaging.

Keywords: high frequency ultrasonic transducer; high spatial resolution; lead-free piezoelectric materials; needle-type.

Abstract

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