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

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.

[1]  M. Sayer,et al.  Single element and linear array PZT ultrasound biomicroscopy transducers , 1997, 1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118).

[2]  Qifa Zhou,et al.  PMN-PT-PZT composite films for high frequency ultrasonic transducer applications. , 2012, Sensors and actuators. A, Physical.

[3]  Changyang Lee,et al.  Single beam acoustic trapping. , 2009, Applied physics letters.

[4]  Kanglyeol Ha,et al.  A theoretical study of the feasibility of acoustical tweezers: ray acoustics approach. , 2005, The Journal of the Acoustical Society of America.

[5]  F. Foster,et al.  Principles and applications of ultrasound backscatter microscopy , 1993, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[6]  H. Chan,et al.  High-frequency ultrasonic transducer fabricated with lead-free piezoelectric single crystal , 2010, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[7]  K. Shung,et al.  Aerosol-deposited KNN–LSO lead-free piezoelectric thick film for high frequency transducer applications , 2010 .

[8]  J. Cannata,et al.  Self-focused ZnO transducers for ultrasonic biomicroscopy. , 2008, Journal of applied physics.

[9]  A. Batten,et al.  Lead-free transducer for non-destructive evaluation , 2007 .

[10]  Qifa Zhou,et al.  Structure and electrical properties of Na0.5Bi0.5TiO3 ferroelectric thick films derived from a polymer modified sol-gel method , 2011, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[11]  Yongxiang Li,et al.  A REVIEW ON LEAD-FREE PIEZOELECTRIC CERAMICS STUDIES IN CHINA , 2011 .

[12]  Changgeng Liu,et al.  Very high frequency (beyond 100 MHz) PZT kerfless linear arrays , 2009, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[13]  K. Yamanouchi,et al.  Ultrasonic micromanipulation of small particles in liquid using VHF-range leaky wave transducers , 1994, 1994 Proceedings of IEEE Ultrasonics Symposium.

[14]  K. Shung,et al.  Piezoelectric films for high frequency ultrasonic transducers in biomedical applications. , 2011, Progress in materials science.

[15]  D. A. Christopher,et al.  Advances in ultrasound biomicroscopy. , 2000, Ultrasound in medicine & biology.

[16]  K. Shung,et al.  Design of efficient, broadband single-element (20-80 MHz) ultrasonic transducers for medical imaging applications , 2003, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[17]  Qifa Zhou,et al.  KNN/BNT composite lead-free films for high-frequency ultrasonic transducer applications , 2011, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[18]  Xiaoxing Wang,et al.  Lead-free piezoceramic cymbal actuator , 2006 .

[19]  Wei Wu,et al.  80 MHz Intravascular Ultrasound (IVUS) transducer , 2011, 2011 IEEE International Ultrasonics Symposium.

[20]  G. Smolensky,et al.  New ferroelectrics of complex composition. IV , 1961 .