Transverse 1-3 piezoelectric ceramic/polymer composite with multi-layered PZT ceramic blocks

An ultrasonic transducer with transverse 1-3 connectivity was fabricated by using multi-layer piezoelectric blocks. The multi-layer ceramic bodies were composed of piezoelectrically active PZN-PZT layers and electrically conducting PZN-PZT/Ag layers. The multi-layer piezoelectric blocks were fabricated by co-extruding and then CNC-machining the thermoplastic body, which consisted of five piezoelectric layers interleaved with four conducting layers. After binder burnout and sintering, the thicknesses of the piezoelectric layer and the electrode were 280 and 70 μm, respectively. The blocks were arranged vertically, and the space between them was filled with an epoxy, in order to fabricate a PZT/epoxy composite with 1-3 connectivity. The apparent piezoelectric coefficient (d¯33,App) of the PZT/epoxy composites utilizing the transverse (d31) mode was ∼6000 pC/N, and the displacement was 4.5 μm at 800 V (length of specimen: 16 mm). These values increased linearly with decreasing thickness and increasing length of the layers. The principal resonance frequency was 60 kHz, at which the displacement was 270 nm with the applied voltage of 10 V (d¯33,App∼27,000 pC/N).