Strength and elastic modulus of lanthanum strontium cobalt ferrite membrane materials

Mixed ionic electronic ceramic transport membranes have a large potential for industrial oxygen supply and carbon emission reduced fossil power plant concepts. Although permeation and phase stability are main development aspects, mechanical robustness is of concern especially for the long term performance and reliability under application relevant thermo-mechanical loads. Lanthanum strontium cobalt ferrite materials appear to be advantageous, especially with respect to CO2 stability. However, the effect of the A-site stoichiometry on the mechanical properties needs to be assessed. Furthermore, advanced design concepts rely on thin layers supported by a porous substrate and therefore also the porosity is an important factor. Hence, these aspects were investigated for dense and porous La0.6Sr0.4Co0.2Fe0.8O3−δ and dense La0.38Sr0.62Co0.2Fe0.8O3−δ. The specimens were investigated using a ring-on-ring bending set-up. The work summarizes the effect of the stoichiometry and porosity on the mechanical properties and compares the temperature dependencies of elastic moduli and fracture stresses.