Water vapour effects on corrosion of Fe–Cr and Fe–Cr–Ni alloys containing cerium and manganese in CO2 gas at 818 °C

Abstract

Model alloys Fe–9Cr, Fe–20Cr and Fe–20Cr–20Ni (wt.%) with 0.1% Ce or 2% Mn were exposed to Ar–20CO2–20H2O gas at 818°C, and the results compared with those of reaction with Ar–20CO2. Water vapour accelerated the corrosion of all Fe–9Cr alloys, and hastened the onset of breakaway oxidation for Fe–20Cr and Fe–20Cr–20Ni. Manganese additions prevented breakaway of the ferritic alloy, and retarded it for the austenitic, but cerium had no effect. All alloys except Mn-bearing variants were simultaneously carburised. Beneficial effects of manganese on high chromium content alloys are discussed in terms of scale phase constitutions.