Carburization of three Fe-19Ni-21Cr- x Al ( x = 0, 2, 6 at.%) alloys at 900 °C in oxygen-contaminated CH 4 /H 2 atmospheres

Abstract The corrosion of three Fe-19Ni-21Cr- x Al ( x = 0, 2, 6 at.%) alloys was studied at 900 °C in 10% CH 4 /H 2 and 1.57% CH 4 /H 2 . All alloys followed complex kinetics. Addition of 2 at.% Al had a slight effect on the corrosion behavior, while that of 6 at.% Al reduced the carbon attack, but was still insufficient to form protective Al 2 O 3 scales. The concept of virtual carbon activity was applied to examine the deviation from equilibrium of the methane decomposition reaction. Moreover, a treatment of internal oxidation of ternary alloys was used to describe the internal carburization kinetics.