The ferroelectric properties of piezoelectric ceramic/polymer composites for acoustic emission sensors

Two different mixed connectivity composites, consisting of a ferroelectric ceramic powder of calcium modified lead titanate (PTCa) dispersed in a poly mer matrix, have been fabricated and their ferroelectric properties have be en investigated. Hysteresis measurements have been conducted on composites of PTCa with a polar polymer of polyvinylidene trifluoroethylene (P(VDF-TrF E)) and PTCa with a thermosetting epoxy resin to determine the coercive fie lds and remanent polarization of the two different composites. The composit es show noticeable differences in their behavior during poling along with t he values of their piezoelectric coefficients, with the composite of PTCa/P (VDF-TrFE) showing enhanced piezoelectric activity over that of PTCa/epoxy. This paper reports on the polarization properties and the microstructural nature of the composites.