Microgeometry, piezoelectric sensitivity and anisotropy of properties in porous materials based on Pb(Zr, Ti)O3

Relations between the microgeometry, piezoelectric sensitivity and piezoelectric anisotropy are studied in porous composite materials based on Pb(Zr, Ti)O-3 ceramics. Systems of micrographs of cuts being parallel and perpendicular to the polarization direction are first shown for the porosity range v(p) = 0.05 - 0.57, and examples of microcracking at v(p) = 0.57 are considered. Experimental data on longitudinal and hydrostatic piezoelectric coefficients and squared figures of merit are represented as functions of v(p), and nonmonotonic behavior of the piezoelectric anisotropy factor with increasing v(p) is analyzed in the context of changes in the microgeometry. Experimental results are compared to those derived from approximation formulae for the related porous ceramic.