Arabian Journal for Science and Engineering>2015>40>9>2739-2746
The aim of this study was to investigate the oxidation behavior of nickel-base superalloys (Inconel 600 and Hastelloy C-22) by the determination of the oxidation rates of alloys at elevated temperatures and at ambient air. The cyclic oxidation method was adapted by heating of alloys periodically in still air at 900, 1000 and 1100∘C1100∘C followed by cooling at ambient temperature. The weight change measurement was recorded during the cyclic oxidation tests. The X-ray diffraction and microstructure study were also used as characterization methods to illustrate the properties of studied alloys and oxide film that formed on the surface of oxidized alloys. Inconel 600 and Hastelloy C-22 showed their ability to develop a uniform protective oxide film. The oxide film that formed on both alloys was chromia oxide Cr2O3 with smaller amount of spinel oxide NiCr2O4. The results of the weight gain measurements suggest that the oxidation kinetics of both alloys follows the parabolic behavior during the experimental tests. Also both alloys at 1100∘C1100∘C exhibited severe spallation of oxide film with linear decreasing in the weight change measurements. The p-kp model was implemented to describe the subsequent cyclic process of oxide growth and spalling.
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