Oxidation, high-temperature, of steel

D. Poirier, E. W. Grandmaison, M. D. Matovic, K. R. Barnes and B. D. Belson, High temperature oxidation of steel in an oxygen-enriched low NO furnace environment , IFRF Combustion loumal. Article Number 200602, September 2006 (this article was downloaded directly from the Internet). 

B.-K. Kim and J. A. Szpunar, Anisotropic microstructure of iron oxides formed during high temperature oxidation of steel . Mater. Sci. Forum 408-412, 1711-1716 (2002). 

E.J. Opila, N.S. Jacobson, D.L. Myers, and E.H. Copland, Predicting oxide stability in high-temperature water vapor, Journal of the Minerals, Metals, and Materials Society 58 22-28, 2006 I. Kvernes, M. Oliveira, and P. Kofstad, High temperature oxidation of Fe-13Cr xAl alloys in air/water vapor mixtures, Corrosion Science 17 237-52, 1977 H. Asteman, J.-E. Svensson, M. Norrell, and L.-G. Johansson, Influence of water vapor and flow rate on the high-temperature oxidation of 304L Effect of chromium oxide hydroxide evaporation. Oxidation of Metals 54 11-26,2000 J.M. Rakowski and B.A. Pint, Observations on the effect of water vapor on the elevated temperature oxidation of austenitic stainless steel foil. Proceedings of Corrosion 2000, NACE Paper 00-517, NACE International, Houston, Texas, 2000 E. Essuman, G.H. Meier, J. Zurek, M. Hansel, and W.J. Quadakkers, The effect of water vapor on selective oxidation of Fe-Cr Alloys, Oxidation of Metals 69 143-162,2008 E.J. Opda, Oxidation and volatilization of silica formers in water vapor. Journal of the American Ceramic Society 86(8) 1238-1248,2003. 

A metal resists corrosion by forming a passive film on the surface. This film is naturally formed when the metal is exposed to the air for a period of time. It can also be formed more quickly by chemical treatment. For example, nitric acid, if applied to austenitic stainless steel, will form this protective film. Such a film is actually a form of corrosion, but once formed it prevents further degradation of the metal, provided that the film remains intact. It does not provide an overall resistance to corrosion because it may be subject to chemical attack. The immunity of the film to attack is a fimction of the film composition, temperature, and the aggressiveness of the chemical. Examples of such films are the patina formed on copper, the rusting of iron, the tarnishing of silver, the fogging of nickel, and the high-temperature oxidation of metals. 

L. SuM ez, R. Coto, X. Vanden Eynde, M. Lamberigts and Y. Houbaert, High temperature oxidation of ultra-low-carbon steel , Def. Diff. Forum 258-260, 158-163 (2006). 

Caplan D and Cohen M (1959), High Temperature Oxidation of Chromium-Nickel Steels, ... 

Metallurgy. The strong affinity for oxygen and sulfur makes the rare-earth metals useflil in metallurgy (qv). Mischmetal acts as a trap for these Group 16 (VIA) elements, which are usually detrimental to the properties of steel (qv) or cast iron (qv). Resistance to high temperature oxidation and thermomechanical properties of several metals and alloys are thus significantly improved by the addition of small amounts of mischmetal or its siUcide (16,17). 

Since the paper by Pilling and Bedworth in 1923 much has been written about the mechanism and laws of growth of oxides on metals. These studies have greatly assisted the understanding of high-temperature oxidation, and the mathematical rate laws deduced in some cases make possible useful quantitative predictions. With alloy steels the oxide scales have a complex structure chromium steels owe much of their oxidation resistance to the presence of chromium oxide in the inner scale layer. Other elements can act in the same way, but it is their chromium content which in the main establishes the oxidation resistance of most heat-resisting steels. 

Several features of the early model (Fig. 6) have been modified in the present-day, high-temperature version of this calorimeter (Fig. 7) (37). Depending upon the temperature range envisaged, the block is made of refractory steel, alumina, or beryllium oxide and is machined to house the calorimeter itself. The thermoelectric pile (about 50 platinum to platinum-rhodium thermocouples) is affixed in the grooves of an alumina plate (A), which is permanently cemented to two cylindrical tubes of alumina (B). Cylindrical containers of platinum (C) ensure the uniformity of the temperature distribution within the calorimeter cells. 

If local stresses exceed the forces of cohesion between atoms or lattice molecules, the crystal cracks. Micro- and macrocracks have a pronounced influence on the course of chemical reactions. We mention three different examples of technical importance for illustration. 1) The spallation of metal oxide layers during the high temperature corrosion of metals, 2) hydrogen embrittlement of steel, and 3) transformation hardening of ceramic materials based on energy consuming phase transformations in the dilated zone of an advancing crack tip. 

Pretreatments of Stainless Steels - Crevice Corrosion and High Temperature Oxidation (AES)... 

Results—High Temperature Oxidation. Two studies have shown that oxidation of annealed wrought 40 pm grain sized 304 stainless steel in air at 800°C produced a rapidly growing iron-rich oxide (47, 48). Oxidation of the same material in 10 Pa oxygen allowed the equilibrium Cr-rich oxide to form as shown in Fig. 10a. Additional oxidation in air at 800°C caused very little change in this protective layer (Fig. 10b), while other parts of the sample without the preoxidation treatment grew a thick Fe-rich oxide layer. 

Implantations of yttrium and cerium in 15 % Cr/4% A1 steel and aluminized coatings on nickel-based alloys did not improve the high-temperature oxidation resistance even though conventional yttrium alloy addition had an effect. The differences for the various substrates are attributed to different mechanisms of oxidation of the materials. The austenitic steel forms a protective oxide film and the oxidation proceeds by cation diffusion. Thus, the yttrium is able to remain in a position at the oxide/metal interface. The other materials exhibit oxides based on aluminum. In their growth anion diffusion is involved which means an oxide formation directly at the oxide/metal interface. The implanted metals may, therefore, be incorporated into the oxide and lost by oxide spalling. 

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