A dual frequency ultrasonic transducer based on BNBT-6/epoxy 1-3 composite

A lead-free piezoelectric ceramic, 0.94(Bi0.5Na 0.5) TiO 3–0.06BaTiO 3 (BNBT-6), was used to fabricate 1-3 composite ultrasonic transducers. BNBT-6 ceramic has a high thickness electromechanical coupling coefficient k t of 0.46 and a low planar coupling coefficient k p (∼0.26). A 1-3 composite with...

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Bibliographic Details
Published in:	Materials science & engineering. B, Solid-state materials for advanced technology Solid-state materials for advanced technology, 2003-05, Vol.99 (1), p.147-150
Main Authors:	Wang, Dan-Yang, Chan, Helen Lai-Wa
Format:	Article
Language:	eng
Subjects:	1-3 Composite Dual frequency ultrasonic transducer Lead-free ceramics
Online Access:	Get full text
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Summary:	A lead-free piezoelectric ceramic, 0.94(Bi0.5Na 0.5) TiO 3–0.06BaTiO 3 (BNBT-6), was used to fabricate 1-3 composite ultrasonic transducers. BNBT-6 ceramic has a high thickness electromechanical coupling coefficient k t of 0.46 and a low planar coupling coefficient k p (∼0.26). A 1-3 composite with 0.575 mm ceramic width and 0.225 mm epoxy gap was fabricated by a dice-and-fill technique. Resonance characteristics of the composite were measured as a function of sample thickness. Mode-coupling theory was applied to calculate the resonance frequencies of the ceramic rods inside the 1-3 composites. The changes in resonance frequencies with composite thickness showed reasonable agreement with the theoretical predictions. With the width to thickness ratio ( L/ H) of the ceramic rods close to 1.45, the thickness mode coupled to the lateral mode and the composite showed two strong resonance modes in the impedance spectrum. At this aspect ratio, the composite was constructed into a dual frequency ultrasonic transducer. The pulse-echo response, bandwidth and insertion loss of the transducer were measured. The good transducer performance indicated that the BNBT-6/epoxy 1-3 composite would be a promising lead-free material for medical imaging applications.
ISSN:	0921-5107 1873-4944