Microstructural and electrical characterizations of chemically prepared Ce0.8Gd0.2-x(Ag, Sr)xO1.9 (0 ≤ x ≤ 0.03)

Gadolinia-doped ceria with co-additions of Sr and Ag were prepared by the cation complexation technique. The influence of co-additives on the densification, microstructure and electrical conductivity of the matrix were investigated by dilatometry, scanning electron microscopy and impedance spectroscopy, respectively. Both co-additives promoted changes on the densification behavior of the matrix. Strontium promoted densification and grain growth, whereas silver did not change the mean grain size but slowed down the densification of gadolinia-doped ceria. The grain conductivity of samples containing silver is considerably higher than that of pure gadolinia-doped ceria. The effect of strontium addition is predominant on the grain boundary by reducing the blocking effect. The apparent activation energy for grain conduction is lower for samples containing co-additives. (C) 2012 Elsevier B.V. All rights reserved.