Anomalies in the thermomechanical behavior of Ba0.5Sr0.5Co0.8Fe0.2O3−δ ceramic oxygen conductive membranes at intermediate temperatures

Abstract
The thermomechanicalproperties of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 − δ (BSCF) were measured using ring-on-ring tests and depth-sensitive microindentation. The cubic BSCF material exhibits an anomaly in mechanical properties between 200 and 400 ° C . The observed anomaly is attributed to the transition of Co 3 + spin states which is experimentally confirmed by susceptibility measurements. Furthermore, slip lines were observed around the impression when indentation tests were carried out above 260 ° C .