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

In this paper, 0.36BiScO(3)-0.64PbTiO(3) (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.