0.36BiScO3–0.64PbTiO3/Epoxy 1–3 Composite for Ultrasonic Transducer Applications

Abstract

In this paper, 0.36BiScO3–0.64PbTiO3 (BSPT) were chosen as piezoelectric materials because of their higher Curie temperature and comparable piezoelectric properties to commercially available lead-zirconate-titanate polycrystalline ceramics. To get a broader bandwidth, BSPT/epoxy 1–3 composite was fabricated using the dice and fill method to alleviate the acoustic impedance matching problems. The design of the BSPT/epoxy 1–3 composite was guided by W. A. Smith theory to get largest electromechanical coupling coefficients. Finite element simulation was utilized for optimal transducer design. 10-MHz transducers were fabricated using BSPT/epoxy 1–3 composite and monolithic BSPT ceramics with the same fabrication process. Electrical and acoustic properties of the transducers were characterized systematically. The monolithic BSPT ceramics ultrasonic transducer has a center frequency of 10.57 MHz, a electromechanical coupling coefficients of 0.579, and a bandwidth of 24.31%. The BSPT/epoxy 1–3 composite ultrasonic transducer has a little lower center frequency (8.93 MHz), a larger effective electromechanical coupling coefficients (0.608), and a broader bandwidth (41.59%). The simulation result matched well with measured parameter, which indicate the BSPT/epoxy 1–3 composite is a potential material in application of high frequency and high resolution.