Oxidation of low carbon steel in multicomponent gases. Part 1: Reaction mechanisms during isothermal oxidation
- McGill Univ. Montreal, Quebec (Canada)
- Ecole Polytechnique, Montreal, Quebec (Canada). Dept. of Metallurgy and Materials Engineering
The article describes rates of oxidation of low carbon steel in various nitrogen-based atmospheres of O{sub 2}, CO{sub 2}, and H{sub 2}O in the temperature range 800 C to 1,150 C. In characterizing the oxidation process, the weight gains of the samples per unit surface area vs time data were analyzed. Reaction rates during oxidation in the binary atmospheres of Co{sub 2}-N{sub 2} and H{sub 2}O-N{sub 2} followed a linear rate law and were found to be proportional to the partial pressures of CO{sub 2} or H{sub 2}O. These rates were controlled by rate of reactions at the oxide surface and were highly dependent on oxidation temperature. The activation energies of the phase boundary reactions obtained were approximately 274 and 264 kJ/mole, for oxidation in CO{sub 2} and H{sub 2}O atmospheres, respectively. Oxidation in gases containing free oxygen showed that the main oxidizing agent was the free oxygen and that additions of CO{sub 2} and H{sub 2}O had little effect on the magnitude of the initial oxidation rates. Experiments for oxidation in multicomponent gases showed that the overall oxidation rates were the additions of rates resulting from oxidation with the individual gaseous species O{sub 2}, CO{sub 2}, and H{sub 2}O. Oxidation in these atmospheres exhibited an initial linear rate law which gradually transformed into a parabolic. Examination of scale microstructure after 1 hour of oxidation showed that, for oxidation in carbon dioxide and water vapor atmospheres, only wustite was present, while in atmospheres containing free oxygen, all three iron oxides, wustite, magnetite, and hematite, were present.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 540992
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 28, Issue 8; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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