CARBURIZATION OF CR-BASED ODS ALLOYS IN SOFC RELEVANT ENVIRONMENTS

Chromium based ODS alloys are being discussed as interconnector materi als in solid oxide fuel cells (SOFC's). One of the major requirements for the interconnect material is sufficient corrosion resistance in th e anode and cathode side gases at the operating temperature of around 950 degrees C. In the present study the corrosion behaviour of a numbe r of chromium based ODS alloys has been investigated in carbon contain ing simulated anode gas of an SOFC. Under these experimental condition s all alloys studied are prone to carburization. The carbon uptake, wh ich mainly occurs in the early stages of exposure, leads to the format ion of a mixed carbide/oxide laver beneath the external chromia scale. The carburization resistance of the alloys depends on the type and co ncentration of the oxide dispersion but even to a larger extent on its distribution. Therefore the cartful control of the alloy manufacturin g process is of great significance for obtaining sufficient carburizat ion resistance under SOFC conditions.