Combustion processed nano-sized Ce0.79Sm0.20Co0.01O2-delta (CSCoO) and Ce0.80Sm0.20O2-delta (CSO) were sintered at various temperatures, and mechanical properties and microstructures were characterized. The results demonstrate that besides a lowering of sintering temperature to achieve sufficient densification, the doping of very minor amounts of CoO (1 mol%) to CSO significantly enhanced mechanical properties. The CSCoo sintered at 1100 degrees C exhibits a biaxial flexural strength of 354 +/- 42 MPa which compared with 194 +/- 57 MPa for CSO with a similar relative density sintered at 1400 degrees C. This slight modification in chemical composition also resulted in a slight improvement in micro-hardness. (C) 2011 Elsevier B.V. All rights reserved.