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

► A slight compositional modification of CSO into CSCoO by doping with 1 mol% CoO offered two advantages: (a) decreased densification temperature and (b) significantly enhanced mechanical properties. ► The flexural strength was significantly increased even at much lower sintering temperatures by doping with CoO. ► This slight modification in composition also resulted in an improvement in microhardness. ► The improvement of mechanical properties can be ascribed to two different fracture mechanisms: a complete transgranular mode for CSCoO, and the mixed type of intergranular (dominant) and transgranular mode for CSO.