Title :
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
Abstract :
A lead-free Bi0.5Na0.5TiO3 (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; Bi0.5Na0.5TiO3; 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;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2013.2726
