Studies on mechanical behavior of LSFT-CGO dual-phase membranes at elevated temperatures in ambient air and slightly reducing environments

This paper discusses the mechanical behavior of La0.2Sr0.8Fe0.6Ti0.4O3−δ (LSFT)-Ce0.9Gd0.1O2−δ (CGO) (40:60 vol%) dual-phase ceramic membranes at elevated temperatures in ambient air and slightly reducing conditions. Fracture strength of the LSTF-CGO membranes was observed to decrease upon exposure to increasing reducing conditions. Changes associated with the oxygen stoichiometry at elevated temperatures in the N2 environment were shown to play a significant role in the fracture behavior of dual-phase membranes. In actual application environments–for example, in a reactor, where the pO2 may vary from 0.2 to 10–14 atm–the mechanical stability of this type of dual-phase membrane primarily depends on the distribution of residual stresses arising from differential chemical/thermal expansion of the individual phases. The present study is of immense importance for anyone designing dual-phase ceramic membranes of LSFT-CGO for pertinent applications.