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The Effect of Water Vapor on Selective Oxidation of Fe–Cr Alloys

“…No indication by EDX analysis for the presence of Fe in the chromia scale could be found. The SEM results confirm that the chromia scale which formed in the Ar-H 2 -H 2 O gas was slightly thicker than that found in Ar-20%O 2 , in agreement with observations from several authors for oxidation of pure Cr, Fe-Cr, and Ni-Cr base alloys [1][2][3][4][5][6]. A very high oxidation rate (essentially linear) was observed in Ar-H 2 O (Fig.…”

“…The growth rate of chromia on pure chromium in the temperature range 900-1,050°C has been observed to be more rapid in water vapor and hydrogen/ water vapor mixtures [1][2][3] than in dry oxygen. A similar acceleration was observed when the Cr contained dissolved hydrogen prior to exposure [4].…”

Oxidation After Breakdown of the Chromium-Rich Scale on Stainless Steels at High Temperature: Internal Oxidation

“…Addition of small amounts of sulfur dioxide has been shown to prolong the incubation time for breakaway oxidation in the presence of KCl and to slow down scale growth after breakaway [20]. [16,[21][22][23]. Tveten et al [22] suggested that exposure to water vapor results in uptake of protons which influence the transport properties of the oxide.…”

“…[16,[21][22][23]. Tveten et al [22] suggested that exposure to water vapor results in uptake of protons which influence the transport properties of the oxide. Essuman et al [16] argued that hydrogen dissolution into the alloy enhances the inward diffusion of oxygen in the alloy, promoting internal oxidation and hindering the formation of an external chromia scale.…”

“…H 2 O environment must have other causes. Various explanations have been suggested for the effect of water vapor at low oxygen activity [16,[21][22][23]. In addition, one environment was selected that does not include water vapor or chlorine-containing species (K 2 CO 3 ?…”