Fabrication and geometrical factors of a novel piezoelectric composite

A novel 0.25PZN-0.75PLZT ceramic/epoxy resin composite with spiral ceramic structure was fabricated by the roll forming-curling method. The composites were investigated for dielectric and piezoelectric properties, while the volume fraction of ceramic phase and the ratio of width to thickness l(w)/l(t) of the ceramic ring were varied. In addition to a high electromechanical coupling coefficient (K-t = 89%)with a 25% volume fraction and low acoustic impedances, the composite was found to yield optimum figure of merit (FOM) value of 77.1 x 10(-12) m(2)/N with a 11% volume fraction when the ratio of width to thickness l(w)/l(t) of the ceramic ring was 0.4. Furthermore, for a given volume fraction of the ceramic phase, the properties electromechanical coupling coefficient (K-t) and the figure of merit (FOM) were all dependent on the ratio of width to thickness l(w)/l(t) of the ceramic ring. (C) 2014 Published by Elsevier Ltd and Techna Group S.r.l.