Investigation of the structural and electrical properties of Co-doped BaCe0.9Gd0.1O3-δ

In the present work the effect of cobalt oxide addition on the density and on the electrical properties of gadolinium-doped barium cerate is investigated. A series of BaCe0.9-xGd0.1CoxO3-delta (x = 0.00, 0.01, 0.03, 0.05, 0.07, 0.10) samples were prepared according to the conventional solid state reaction synthesis technique. The experimental results indicated that the addition of cobalt oxide leads to the improvement of the sintering properties and the enhancement of the grain dimensions. It was found that the investigated complex oxides crystallize at cubic singony. Moreover, according to the X-ray diffraction (XRD) and the scanning electron microscopy (SEM) analyses, the prepared samples are single-phase in the range of 0.00 <= x <= 0.10, while at compositions of x >= 0.03 there is almost no open porosity. According to the four-probe dc electrical conductivity measurements, the conductivity of the BaCe0.9-xGd0.1CoxO3-delta samples is inferior to the undoped ones (BaCe0.9Gd0.1O3-delta-BCG) in wet air atmosphere. However, the presence of Co in the range of 0.03 <= x <= 0.10 at higher temperatures (800-900 degrees C) has smaller impact on the electrical conductivity values. Finally, in wet hydrogen atmosphere the electrical conductivity values of the 1 mol% Co-doped sample were found to be close enough to the ones of the undoped sample, leading to the conclusion that cobalt can be effectively employed as a sintering additive of gadolinium-doped barium cerates. (C) 2010 Elsevier B.V. All rights reserved.