A multilayer piezoelectric ceramic/polymer composite with 2–2 connectivity was fabricated by thermoplastic green machining after co‐extrusion. The multilayer ceramic body was composed of piezoelectrically active lead zirconate titanate (PZN)–lead zinc niobate (PZN)‐lead zirconate titanate (PZT) layers and electrically conducting PZN–PZT/Ag layers. After co‐extruding the thermoplastic body, which consisted of five piezoelectric layers interspersed with four conducting layers, it was computer numeric‐controlled machined to create periodic channels within it. Following binder burnout and sintering, an 18 vol% array of 190 μm thin PZT slabs with a channel size of 880 μm was fabricated. The channels were filled with epoxy in order to fabricate a PZN–PZT/epoxy composite with 2–2 connectivity. The piezoelectric coefficient (effective d33) and hydrostatic figure of merit (dh×gh) of the PZN–PZT/epoxy composite were 1200 pC/N and 20 130 × 10−15 m2/N, respectively. These excellent piezoelectric characteristics as well as the relatively simple fabrication procedure will contribute in widening the application range of the piezoelectric transducers.

A piezoelectric ceramic/polymer composite with 2‐2 connectivity was fabricated by thermoplastic green machining. A thermoplastic body, consisting of 60 vol% lead zirconate titanate ceramic particles (PZT) and 40 vol% thermoplastic binders, was computer numeric controlled‐machined, creating periodic channels in the green PZT body. Following thermal treatment (binder burnout and sintering), a 25 vol% array of 147 μm thin PZT slabs with an aspect ratio of seven separated by 442 μm channels was fabricated. The channels were infiltrated with epoxy resin, in order to fabricate the PZT/epoxy composite with 2‐2 connectivity. This novel process was evaluated in terms of the machinability and sinterability of the thermoplastic PZT compound. Also, the electromechanical properties of the PZT/epoxy composite were measured.

A multilayer ceramic actuator composed of piezoelectrically active Pb(Zn 1/3 Nb 2/3 ) 0.2 -Pb(Zr 0.5 Ti 0.5 )O 0.8 (PZN-PZT) layers and electrically conducting PZN-PZT/Ag layers was fabricated by the co-extrusion process. For the piezoelectric layers, PZN-PZT, which is sinterable at a low temperature (9001C), was used. For the conducting layers, a PZN-PZT/Ag composite, made by mixing silver particles with the PZN-PZT matrix, was employed. For the co-extrusion process, piezoelectric and conducting feedrods were made by mixing the PZN-PZT and PZN-PZT/Ag, respectively, with a thermoplastic polymer. The initial feedrods, which were composed of five 3 mm-thick PZN-PZT layers, two 1.5 mm-thick PZN-PZT layers, and six 1 mmthick PZN-PZT/Ag layers, were co-extruded through a 24 mm  2 mm reduction die at 1051C to produce continuous multilayered green sheets. The sheets were stacked, warm pressed, and sintered at 9001C for 4 h after binder burnout. The sintered multilayer actuator showed distinct layers without any reaction products or cracks at the interface. The thicknesses of the piezoelectric and conducting layers were about 200 and 70 lm, respectively. The displacement of the multilayer actuator, composed of 40 piezoelectric layers (with a total height of 10.8 mm), was about 10 lm at an applied voltage of 500 V.

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