A new theoretical approach to the thermodynamic calculation of high-temperature oxidation of Ni-Cr alloys

In calculations, not only the Gibbs formation energy of nickel and chromium oxides and thermodynamic activities of the alloy components, but also the Gibbs surface energy of a Ni-Cr alloy is taken into account. The method is based on the adsorption model of the alloy oxidation, according to which th...

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Bibliographic Details
Published in:Protection of metals 2006-05, Vol.42 (3), p.221-226
Main Authors: Andreev, Yu Ya, Shumkin, A A
Format: Article
Language:English
Subjects:
Alloys
Solid solutions
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Summary:In calculations, not only the Gibbs formation energy of nickel and chromium oxides and thermodynamic activities of the alloy components, but also the Gibbs surface energy of a Ni-Cr alloy is taken into account. The method is based on the adsorption model of the alloy oxidation, according to which the adsorption of an alloy component with the smaller surface energy, namely, nickel, at the alloy-oxide film interface boundary shifts the dynamic equilibrium between the alloy and oxide-film components toward the formation of NiO. For the oxidation of Ni-Cr alloys, which are solid solutions with an fcc lattice, at 1123 to 1473 K, concentration boundaries of the chromium content in the alloy are calculated for the case of the prevailing formation of Cr^sub 2^O^sub 3^ oxide, which determines the high heat resistance of Ni-Cr alloys.[PUBLICATION ABSTRACT]
ISSN:0033-1732
2070-2051
1608-327X
2070-206X
DOI:10.1134/S0033173206030039