|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|4914588||1362626||2018||10 صفحه PDF||ندارد||دانلود کنید|
â¢Oxidation of alloy 625 and 825 in supercritical water containing 5000Â ppm oxygen.â¢Pitting corrosion was found on surfaces of both alloy 625 and 825.â¢The oxide scales on alloys composed of Fe2O3, NiFe2O4 and NiO.â¢Transpassive dissolution occurred and Cr was oxidized to its hexavalent compound.â¢Penetration rate of alloy 625 and 825 was 28Â Î¼m/year and 31.5Â Î¼m/year, respectively.
In this study, the oxidation behavior of Ni-based alloys 625 and 825 in supercritical water containing 5000Â ppm of dissolved oxygen at 500Â Â°C was investigated by scanning electron microscopy coupled with energy-dispersive spectroscopy, X-ray diffraction, and laser Raman spectroscopy. Alloy 625 and 825 showed a pitting-like phenomenon after 500Â h of exposure. The structure and composition of the oxides formed on alloy 625 and 825 were similar, namely, an outer layer of Fe oxides, spinel structures, and Ni(OH)2; and an inner NiO layer. The mechanism for the formation of the oxide films was proposed, and the factors affecting corrosion of Ni-based alloys were discussed in detail. In addition, the corrosion resistance performance of alloy 625 and 825 was compared.
Graphical abstractDownload high-res image (133KB)Download full-size image
Journal: The Journal of Supercritical Fluids - Volume 131, January 2018, Pages 1-10