title: Lead-free KNLNT piezoelectric ceramics for high-frequency ultrasonic transducer application.
abstract: This paper presents the latest development of a lead-free piezoelectric ceramic and its application to transducers suitable for high-frequency ultrasonic imaging. A lead-free piezoelectric ceramic with formula of (K(0.5)Na(0.5))(0.97)Li(0.03)(Nb(0.9) Ta(0.1))O(3) (abbreviated as KNLNT-0.03/0.10) was fabricated and characterized. The material was found to have a clamped dielectric constant epsilon(33)(S)/epsilon(0)=890, piezoelectric coefficient d(33)=245 pC/N, electromechanical coupling factor k(t)=0.42 and Curie temperature T(c)>300 degrees C. High-frequency (40 MHz) ultrasound transducers were successfully fabricated with the lead-free material. A representative lead-free transducer had a bandwidth of 45%, two-way insertion loss of -18 dB. This performance is comparable to reported performances of popular lead-based transducers. The comparison results suggest that the lead-free piezoelectric material may serve as an alternative to lead-based piezoelectric materials for high-frequency ultrasonic transducer applications.
authors.affiliation: NIH Transducer Resource Center, University of Southern California, Los Angeles, CA 90089, USA. daweiwu@usc.edu
authors.forename: D W
authors.initials: DW
authors.lastname: Wu
authors.forename: R M
authors.initials: RM
authors.lastname: Chen
authors.forename: Q F
authors.initials: QF
authors.lastname: Zhou
authors.forename: K K
authors.initials: KK
authors.lastname: Shung
authors.forename: D M
authors.initials: DM
authors.lastname: Lin
authors.forename: H L W
authors.initials: HL
authors.lastname: Chan
mesh_terms: D002516:Ceramics / Q000737:chemistry* / Q000528:radiation effects*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007854:Lead; D008422:Materials Testing; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods
chemical_list: D007854:Lead