Lead-free BNT composite film for high-frequency broadband ultrasonic transducer applications

Author

Xingwei Yan ; Hongfen Ji ; Kwok Ho Lam ; Ruimin Chen ; Fan Zheng ; Wei Ren ; Qifa Zhou ; Shung, K. Kirk

Author_Institution

Key Lab. of the Minist. of Educ. & Int. Center for Dielectr. Res., Xi´an Jiaotong Univ., Xi´an, China

Volume

60

Issue

7

fYear

2013

fDate

Jul-13

Firstpage

1533

Lastpage

1537

Abstract

A lead-free Bi_0.5Na_0.5TiO₃ (BNT) piezoelectric composite thick film with a thickness of ~11 μm has been fabricated using a modified sol-gel method. Dielectric constant, remnant polarization, and coercive field of the BNT composite film were found to be 1018, 22.6 μC/cm₂, and 76.1 kV/cm, respectively. The film was used to fabricate a high-frequency needle transducer and the performance of the transducer was measured. The transducer without a matching layer exhibits a center frequency of 98 MHz and a -6-dB bandwidth of 86%. A wire phantom image acquired using the transducer shows an axial resolution of 15 ¿m and lateral resolution of 68 μm, respectively. Results from this study suggest that the BNT composite film is a promising lead-free piezoelectric material for high-frequency broadband ultrasonic transducer applications.

Keywords

bismuth compounds; composite materials; dielectric polarisation; ferroelectric coercive field; high-frequency effects; permittivity; piezoelectric thin films; piezoelectric transducers; sodium compounds; sol-gel processing; ultrasonic transducers; Bi_0.5Na_0.5TiO₃; axial resolution; coercive field; dielectric constant; high-frequency broadband ultrasonic transducer applications; high-frequency needle transducer; lateral resolution; lead-free BNT composite film; piezoelectric composite thick film; remnant polarization; sol-gel method; wire phantom image;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/TUFFC.2013.2726

Filename

6552404