Thermodynamics of Congruent Oxidation
Congruent oxidation occurs when an alloy oxidizes at constant oxygen chemical potential and temperature to an oxide in which the ratio of metallic components is the same as in the alloy. In alloys that undergo congruent oxidation concentration gradients near the surface are minimized. In this work t...
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2012-10-01
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Online Access: | https://doi.org/10.1515/htmp-2012-0072 |
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doaj-66d8a791b5f843f093708558c4a75d102021-09-06T19:19:51ZengDe GruyterHigh Temperature Materials and Processes0334-64552191-03242012-10-01314-539540310.1515/htmp-2012-0072Thermodynamics of Congruent OxidationJacob K.T.Adharsh R.0Department of Materials Science and Metallurgical Engineering, Maulana Azad National Institute of Technology, Bhopal 462051, IndiaCongruent oxidation occurs when an alloy oxidizes at constant oxygen chemical potential and temperature to an oxide in which the ratio of metallic components is the same as in the alloy. In alloys that undergo congruent oxidation concentration gradients near the surface are minimized. In this work thermodynamic conditions for congruent oxidation of binary and ternary alloys are formulated using the regular solution model to describe thermodynamic mixing properties. The conditions under which congruent oxidation can occur are identified. Congruent oxidation of a binary alloy X-Y will occur only if difference in oxygen potential for the oxidation of the two pure metals is less than twice the difference in regular solution parameters for the oxide and alloy phases (Ω0 − ΩA). In the case of ternary alloys, congruency requirements for both two-phase and three-phase equilibria are discussed. Since the conditions for congruent oxidation of ternary alloy X-Y-Z depends on many parameters, the effect of systematic variation of the binary sets of regular solution parameters on the congruent composition is explored by numerical solution of the governing equations.https://doi.org/10.1515/htmp-2012-0072congruent oxidationcongruent reductionthermodynamicsoxygen potential maxima/minimamiscibility gap |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jacob K.T. Adharsh R. |
spellingShingle |
Jacob K.T. Adharsh R. Thermodynamics of Congruent Oxidation High Temperature Materials and Processes congruent oxidation congruent reduction thermodynamics oxygen potential maxima/minima miscibility gap |
author_facet |
Jacob K.T. Adharsh R. |
author_sort |
Jacob K.T. |
title |
Thermodynamics of Congruent Oxidation |
title_short |
Thermodynamics of Congruent Oxidation |
title_full |
Thermodynamics of Congruent Oxidation |
title_fullStr |
Thermodynamics of Congruent Oxidation |
title_full_unstemmed |
Thermodynamics of Congruent Oxidation |
title_sort |
thermodynamics of congruent oxidation |
publisher |
De Gruyter |
series |
High Temperature Materials and Processes |
issn |
0334-6455 2191-0324 |
publishDate |
2012-10-01 |
description |
Congruent oxidation occurs when an alloy oxidizes at constant oxygen chemical potential and temperature to an oxide in which the ratio of metallic components is the same as in the alloy. In alloys that undergo congruent oxidation concentration gradients near the surface are minimized. In this work thermodynamic conditions for congruent oxidation of binary and ternary alloys are formulated using the regular solution model to describe thermodynamic mixing properties. The conditions under which congruent oxidation can occur are identified. Congruent oxidation of a binary alloy X-Y will occur only if difference in oxygen potential for the oxidation of the two pure metals is less than twice the difference in regular solution parameters for the oxide and alloy phases (Ω0 − ΩA). In the case of ternary alloys, congruency requirements for both two-phase and three-phase equilibria are discussed. Since the conditions for congruent oxidation of ternary alloy X-Y-Z depends on many parameters, the effect of systematic variation of the binary sets of regular solution parameters on the congruent composition is explored by numerical solution of the governing equations. |
topic |
congruent oxidation congruent reduction thermodynamics oxygen potential maxima/minima miscibility gap |
url |
https://doi.org/10.1515/htmp-2012-0072 |
work_keys_str_mv |
AT jacobkt thermodynamicsofcongruentoxidation AT adharshr thermodynamicsofcongruentoxidation |
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1717777734126534656 |