This paper reports on the preparation of a fully dense Gd-doped CeO2 (GDC) at low sintering temperature using CeO2 powder and Gd precipitation in the presence of CoO as a sintering aid. A mixture of CeO2 powder and Gd precipitates was calcined at 700 oC followed by milling that resulted in the GDC (Ce0.8Gd0.2O1.9) powder with an average particle size of 0.46 μm. Sintering of the undoped sample showed a relative density of 99.2% at 1500 oC, whereas the samples doped with 3 mol% and 5 mol% CoO exhibited a significant densification at the lower temperature reaching a relative density of 98.8% at 1200 oC. The electrical conductivities of both doped samples were almost identical but higher than those of the undoped sample at all measuring temperatures.

Keywords: GDC, CeO2 powder, CoO doping, Sintering, Electrical conductivity