Microscale 1-3-Type (Na,K)NbO3-Based Pb-Free Piezocomposites for High-Frequency Ultrasonic Transducer Applications

Fine-grained Pb-free (Na0.535K0.485)(0.95)Li-0.05(Nb0.8Ta0.2)O-3 (NKLNT) piezoceramics prepared by spark plasma sintering (SPS) technique was used to fabricate NKLNT/epoxy 1-3 composites with a modified dice-fill method. Because of its good machinability, SPSed NKLNT ceramic rods could be miniaturized to a lateral width of 50 mu m. After lapping down to 56 mu m in thickness, the composite was used to fabricate an ultrasonic transducer as the active piezoelectric element. This composite transducer showed a bandwidth at -6 dB nearly 90% at a center frequency of 29 MHz, demonstrating that this Pb-free composite thick film is very promising for the fabrication of high-frequency ultrasonic transducers in medical imaging applications.