Impedance spectroscopy analysis of percolation in (yttria-stabilized zirconia)-yttria ceramic composites

(ZrO2:8 mol% Y2O3)+m mol% Y2O3 ceramic composites with nominal yttria concentration varying from 0 to70 mol% (0–82.9 vol.%) were prepared by evaporation of a suspension of ZrO2:8 mol% Y2O3 and Y2O3 in ethanol followed by pressing and sintering. The samples were analyzed by X-ray diffractometry and scanning electron microscopy for microstructural characterization. The electrical properties were studied by impedance spectroscopy (IS) allowing for the separation of the inter- and intragranular components of the electrical conductivity. The percolative behavior of these components was analyzed using the general effective media (GEM) equation and the percolation thresholds found were ∼28 vol.%. The results indicate that impedance spectroscopy provides useful information in addition to the dc techniques concerning the electrical characterization of composite materials.