Mechanical strengthening of Sm-doped CeO2 ceramics by 1 mol% cobalt oxide for solid oxide fuel cell application

Combustion processed nano-sized Ce_0.79Sm_0.20Co_0.01O_2-δ (CSCoO) and Ce_0.80Sm_0.20O_2-δ (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 °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 °C. This slight modification in chemical composition also resulted in a slight improvement in micro-hardness.