Novel piezoelectric ceramic/polymer composite transducers

The design, processing conditions and electromechanical characterization of novel piezoelectric ceramic/polymer composites with 2-2 and 3-3 connectivity is presented. The ceramic structures made of PZT were prepared by Layered Manufacturing, namely by Fused Deposition of Ceramics (FDC) process. The ceramic phase in the form of fibers or sheets was oriented at different orientation angles /spl theta/ with respect to the x/sub 3/ axis of the sample, which varied between 0/spl deg/ and 75/spl deg/, in 15/spl deg/ increments. The sintered structures were placed in Spurr Epoxy polymer and diced in 2mm thickness. The electromechanical and elastic properties were investigated as a function of orientation angle /spl theta/. The longitudinal piezoelectric charge coefficient showed a decrease in the property as the /spl theta/ increases. It was found that as the orientation angle /spl theta/ was increased, the transverse piezoelectric charge coefficient d/sub 3l/ changed its sign from a negative to a positive value at /spl theta/ = 37.5/spl deg/ reaching a maximum value at 45/spl deg/ for both types of composites. Due to the contribution of a positive d/sub 3l/ coefficient, a significant increase in the hydrostatic charge coefficient was observed.