Fabrication of piezoelectric ceramic/polymer composite transducers using fused deposition of ceramics

The fused deposition of ceramics (FDC) technique was used to fabricate piezoelectric ceramic skeletons for the development of piezoelectric composite transducers with 2-2 connectivity for medical imaging. The green parts were designed to have 30 vol% lead zirconate titanate ceramic (PZT-SH) in the final composites. Physical characterization of the sintered samples revealed that 96% of the theoretical density was achieved. Optical microscopy showed that defects due to the FDC mode of deposition, such as small roads and bubbles, were eliminated, because of improvements in powder processing. The electromechanical properties of the final composites were similar to the properties that were obtained for conventionally made composites. A matching layer and a backing layer, as well as wires and an inductor, were added to each FDC composite to fabricate a functional medical imaging transducer. The devices were tested in water using a steel target 3.5 cm thick. Echoes from the target could be detected with all the transducers that were fabricated using FDC, The sensitivities of the transducers were similar to that of a commercial transducer. However, the ringing was much longer than that for a commercial transducer, because the backing layer was not optimized ill the transducers that were fabricated using FDC.