PZT/PLZT - elastomer composites with improved piezoelectric voltage coefficient

Abstract

Lead Zirconate Titanate (PZT) and Lanthanum-modified Lead Zirconate Titanate (PLZT) ceramic sensor materials are widely used because of their excellent piezoelectric coefficients. These materials are brittle, high density and have low achievable piezoelectric voltage coefficients. The density of the sintered ceramics shall be reduced by burnable polymeric sponge method. The achievable porosity level in this case is nearly 60 – 90%. However, the porous ceramic structure with 3-3 connectivity produced by this method is very fragile in nature. The strength of the porous structure is improved with Sylgard^®-184 (silicone elastomer) by vacuum impregnation method maintaining the dynamic vacuum level in the range of -650 mm Hg. The elastomer Sylgard^®-184 is having low density, low dielectric constant and high compliance (as a resultant stiffness of the composites is increased). To obtain a net dipole moment, the impregnated ceramic composites were subjected to poling treatment with varying conditions of D.C. field and temperature. The properties of the poled PZT/PLZT - elastomer composites were characterized with LCR meter for measuring the dielectric constant values (k), d₃₃ meter used for measuring piezo-electric charge coefficient values (d₃₃) and piezo-electric voltage coefficient (g₃₃) values which were derived from d₃₃ values. The voltage coefficient (g₃₃) values of these composites are increased by 10 fold as compared to the conventional solid ceramics demonstrates that it is possible to fabricate a conformable detector.