Effects of water vapor on oxidation behavior of ferritic stainless steels under solid oxide fuel cell interconnect exposure conditions

The oxidation of ferritic stainless steels has been studied under solid oxide fuel cell (SOFC) interconnect “dual” exposure conditions, i.e., simultaneous exposure to air on one side of the sample, and fuel (hydrogen) on the other. It was found that, under the dual exposures, the oxidation behavior of the stainless steels at the airside differed significantly from that observed during exposure to air at both sides. Increased water vapor partial pressure in the air at the airside further accelerated the anomalous oxidation, resulting in nucleation and growth of hematite in the scale that led to a localized attack. The accelerated oxidation and growth of the hematite nodules was a result of combined effects of hydrogen transport from the fuel side to the airside and the presence of increased water vapor.