Influence of Al Particle Size and Lead Zirconate Titanate (PZT) Volume Fraction on the Dielectric Properties of PZT-Epoxy-Aluminum Composites

Abstract

Two-phase PZT-epoxy piezoelectric composites and three phase PZT-epoxy-Al composites were fabricated using a poling voltage of 0.2 kV/mm. The influence of aluminum inclusion size (nano and micron) and (lead zirconate titanate) PZT volume fraction on the dielectric properties of the three phase PZT-epoxy-aluminum composites were experimentally investigated. In general, dielectric and piezoelectric properties of the PZT-epoxy matrix were improved with the addition of aluminum particles. Composites that were comprised of micron scale aluminum inclusions demonstrated higher piezoelectric d33 -strain-coefficients, and higher dielectric loss compared to composites that were comprised of nanosize aluminum inclusions. Specifically, composites comprised of micron sized aluminum particles and PZT volume fractions of 20%, 30%, and 40% had dielectric constants equal to 405.7, 661.4, and 727.8 (pC/N), respectively, while composites comprised of nanosize aluminum particles with the same PZT volume fractions, had dielectric constants equal to 233.28, 568.81, and 657.41 (pC/N), respectively. The electromechanical properties of the composites are influenced by several factors: inclusion agglomeration, contact resistance between particles, and air voids. These composites may be useful for several applications: structural health monitoring, energy harvesting, and acoustic liners.