Mechanical properties of pure and doped cerium oxide

Advanced concepts for oxygen transport membranes focus on thin layers supported by a porous substrate. To warrant long term reliable operation of such systems, an assessment of the mechanical stability of each membrane component is required. With respect to chemical stability, cerium oxide and doped cerium oxides are promising materials for this application. The present work addresses the mechanical properties of cerium oxide variants, aiming to elucidate properties of relevance to the manufacture of reliable cerium oxide components. In particular Ce0.8Gd0.2−yPryO2−δ membrane materials and the influence of an addition 2 mol% of CoO is assessed. Materials preparation and compositional variations are compared with respect to elastic modulus, hardness and fracture toughness, as characterized using depth sensitive indentation. Furthermore, the creep behavior of doped and undoped cerium oxides, that is important for the long term structural stability at temperatures relevant to the oxygen-membranes operation, is assessed and critically discussed.