Ternary piezoelectric single-crystal PIMNT based 2-2 composite for ultrasonic transducer applications

• PIMNT/epoxy 2-2 piezoelectric composite was designed and prepared.
• The PIMNT/epoxy 2-2 composite showed improved piezoelectric and acoustic properties.
• Three ultrasonic transducers were designed and fabricated with three different piezoelectric materials, including PIMNT/epoxy 2-2 composite, PIMNT/epoxy 1-3 composite, and PIMNT single crystal.
• The PIMNT/epoxy 2-2 composite ultrasonic transducer achieved enhanced performance.

In order to take the full advantage of excellent beam-mode piezoelectric and acoustic properties of Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIMNT) single crystal, PIMNT/epoxy 2-2 composite was designed and prepared with PIMNT volume percent of 69. Excellent properties for ultrasonic transducer applications were achieved, including ultrahigh thickness electromechanical coupling coefficient (kt = 86%), large piezoelectric coefficient (d33 = 1200 pC/N), and low acoustic impedance (Z ~ 20 MRayls). Based on the improved properties, a 2 MHz PIMNT/epoxy 2-2 composite ultrasonic transducer was designed, fabricated, and its performance was compared with a PIMNT/epoxy 1-3 composite ultrasonic transducer and a PIMNT single-crystal ultrasonic transducer, respectively. The PIMNT/epoxy 2-2 composite ultrasonic transducer showed a significant enhancement in both relative pulse-echo sensitivity and −6 dB bandwidth, which were 4 dB higher and 20% broader than those of the PIMNT single-crystal ultrasonic transducer and as excellent as the PIMNT/epoxy 1-3 composite ultrasonic transducer. These promising results suggested the great potential for developing high-performance ultrasonic transducers using the PIMNT/epoxy 2-2 composite.