On the oxidation of iron in CO sub 2 + CO mixtures: 2. Reaction mechanisms during initial oxidation

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Oxidation of Metals; (United States)

DOI:https://doi.org/10.1007/BF00666503· OSTI ID:6069826

Bredesen, R; Kofstad, P ^[1]

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1. Univ. of Oslo (Norway)

Oxidation of high purity iron in CO{sub 2} and CO{sub 2} + CO mixtures at different total pressures (0.1-1 atm.) has been studied at 1,000-1,200C. While paper 1 of this study emphasized studies of the relation between scale morphology and reaction kinetics, this paper focuses on the reaction mechanism during the initial oxidation involving growth of wuestite films and scales The reaction behavior is analyzed in terms of coupled kinetics comprising a surface reaction and diffusional transport through the scale. A classical model derived by C Wagner, based on the assumption that the properties and defect concentrations in the scale surface are exactly the same as in bulk wuestite equilibrated in CO{sub 2} + CO mixtures, does not provide a satisfactory description of the reaction kinetics and the gas-pressure dependence of the surface reaction. As an alternative model, it is suggested that the gaseous molecules/species interacts with the surface to form surface complexes, and that surface complexes with CO{sub 2} serve as preferred reaction sites for the surface reaction.

• OSTI ID: 6069826
• Journal Information: Oxidation of Metals; (United States), Journal Name: Oxidation of Metals; (United States) Vol. 35:1-2; ISSN 0030-770X; ISSN OXMEA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CORROSIVE EFFECTS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFUSION
ELEMENTS
EQUATIONS
GRAVIMETRIC ANALYSIS
IRON
IRON COMPOUNDS
IRON OXIDES
KINETICS
LOW PRESSURE
MATHEMATICAL MODELS
MEDIUM PRESSURE
METALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
SCALING
SELF-DIFFUSION
SURFACE PROPERTIES
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VERY HIGH TEMPERATURE