Ionic conductivity of 4 mol%, 9.5 mol% YSZ nanomaterials and (9.5 mol% YSZ)0.98-(Al2O3)0.02 nanocomposites

Abstract

The ionic conductivity of 4 and 9 mol% yttria-doped zirconia nanomaterials (noted, respectively, N4 and N9), of 9.5 mol% yttria-doped zirconia single crystal (noted YSZ) and of a nanocomposite with 2 mol% alumina noted (NC2) was studied using the impedance spectroscopy technique. In this study, our aim was to find optimal conditions for any improvement of ionic conductivity at low temperatures. Experimental results showed that the total ionic conductivity of N4 is higher than that for YSZ single crystals and this for the most part of the temperature range studied (300-500 °C). Comparing N4 with N9, the former exhibited the highest conductivity for the "grain contribution" but not for the "grain boundary contribution". For the nanocomposites NC2, we found a slight increase of the ionic conductivity even at low temperatures compared to the nanomaterial of same yttria content. This work has shown that the conductivity in these materials depends not only on the alumina content but also on the microstructure. © 2005 Elsevier B.V. All rights reserved.