High temperature oxidation of HP40 alloy under H2–H2O and air atmospheres: a surface study |
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| Authors: | Binbin Bao Jinglei Liu Kai Zhang Hong Xu |
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| Institution: | State‐Key Laboratory of Chemical Engineering, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China |
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| Abstract: | In the present work, high temperature oxidation of HP40 alloy was carried out at 1050 °C under H2–H2O and air atmospheres; the influence of atmosphere on surface morphology and composition was studied. Octahedral crystals with considerable spalled regions are present on the surface of alloy oxidized under air, the oxide scale composes of MnCr2O4, Cr2O3 and (Fe, Ni)Cr2O4 and spalled regions exhibit base alloy and SiO2‐rich regions. The surface of alloy oxidized under H2–H2O is fully covered by small granular crystals and blade‐type structures without spallation, and the oxide scale composes of MnCr2O4 and Cr2O3. Moreover, X‐ray photoelectron spectroscopy analysis shows considerable difference in chemical valence states of Mn, Cr and O elements on both alloy surfaces, and hydroxyl compounds exist on the alloy oxidized under H2–H2O atmosphere. Copyright © 2017 John Wiley & Sons, Ltd. |
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| Keywords: | selective oxidation H2– H2O MnCr2O4 HP40 chemical valence state |
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