Lead-free piezoelectric single crystal based 1–3 composites for ultrasonic transducer applications

In this work, lead-free 1–3 composites based on piezoelectric 0.947Na0.5Bi0.5TiO3–0.053BaTiO3 (NBT–0.053BT) single crystal and epoxy are fabricated for ultrasonic transducer applications by a modified dice-and-fill method. Excellent properties for ultrasonic transducer applications have been achieved, such as high electromechanical coupling coefficient (kt = 73%), lower acoustic impedance (Z = 16 MRayl) and moderate dielectric constant. Based on this lead-free piezoelectric single crystal composite, single-element ultrasonic transducer and linear array have been fabricated and characterized. Both types of transducers exhibit similar performance with broad bandwidth of exceeding 100%. The promising results show that these lead-free composites have the potential to be used for high-performance ultrasonic transducers.