title: Lead-free BNT composite film for high-frequency broadband ultrasonic transducer applications.
abstract: 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.
authors.forename: Xingwei
authors.initials: X
authors.lastname: Yan
authors.forename: Hongfen
authors.initials: H
authors.lastname: Ji
authors.forename: Kwok Ho
authors.initials: KH
authors.lastname: Lam
authors.forename: Ruimin
authors.initials: R
authors.lastname: Chen
authors.forename: Fan
authors.initials: F
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Ren
authors.forename: Qifa
authors.initials: Q
authors.lastname: Zhou
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D004867:Equipment Design; D019047:Phantoms, Imaging; D012964:Sodium / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*
chemical_list: D012964:Sodium; D014025:Titanium; D001729:Bismuth