Piezoelectric properties of ferroelectric PZT-polymer composites

The most widely used material for active transducer applications is the fer roelectric ceramic PZT Composites made of ferroelectric ceramics combined w ith polymers have several advantages over pure ceramics. Diphasic composite s of PZT (and La/Ca modified PZT) combined with various polymers such as PV DEF, PVC, PVA, epoxy resin and co-polymers have been widely studied and rep orted in the literature. In this paper we present the preparation and study of PZT-PVDF composites o f 0-3 connectivity. The composites are prepared by two methods, namely (i) the solvent-cast method and (ii) the hot-press method. The piezoelectric st rain coefficient (d(33)) is Studied as a function of volume fraction of PZT in PVDF The dielectric constant (k) is measured as a function of temperatu re and the piezoelectric voltage coefficient (g(33)) Of the composite is de termined. The experimental values of the dielectric constant, d(33) and g33 Of the co mposites are compared with the earlier reported values and the theoretical values proposed by Furukawa ct nl (Furukawa T, Ishida K and Fukada E 1979 J . Appl. Sci. 50 4904) and Bhimasankaram et al (Bhimasankaram T, Suryanaraya na S V and Prasad G P 1998 Cove Sci 4 967). The composite with 0.5 PZT volume fraction prepared by the hot-press method is found to possess a reasonably high d33 value and exhibit good flexibili ty and stability with time.