Water vapor is a major component of most combustion gas streams, and has been shown to generally increase the rate of attack of heat-resistant alloys at elevated temperatures. The role of water vapor in causing accelerated oxidation will be reviewed for a variety of alloys, including austenitic stainless steels, ferritic stainless steels, and nickel-base superalloys. A variety of factors will be considered, including environmental variables such as gas composition and temperature, alloy composition, and specimen thickness. Specifically, iron-base alloys are more susceptible to increased degradation in humidified air, with the initial chromium content playing a significant role in the transition from protective to rapid oxidation. Nickel-base alloys were observed to exhibit altered oxidation kinetics, but did not form rapidly growing oxides.

Subject
Water, Materials, Stainless alloys, Nickel based alloys, Oxide formation, Chromium, Iron content, Vapors, Oxide scales, Superalloys, Stainless steel, Ferritic stainless steel, Oxidation
Keywords:
austenitic stainless steel, ferritic stainless steel, nickel-base superalloy, oxidation, water vapour
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2008
Association for Materials Protection and Performance (AMPP)
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