Thermodynamics of Congruent Oxidation
| Autor: | K. T. Jacob, R Adharsh |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Technology
Work (thermodynamics) Materials science Spinodal decomposition Alloy congruent reduction Regular solution Oxide Chemicals: Manufacture use etc chemistry.chemical_element Thermodynamics TP1-1185 engineering.material Oxygen Metal Condensed Matter::Materials Science thermodynamics chemistry.chemical_compound Mathematics::Metric Geometry congruent oxidation General Materials Science Physics::Chemical Physics Physical and Theoretical Chemistry miscibility gap Chemical technology Materials Engineering (formerly Metallurgy) TP200-248 Condensed Matter Physics chemistry Mechanics of Materials visual_art visual_art.visual_art_medium engineering oxygen potential maxima/minima Ternary operation |
| Zdroj: | High Temperature Materials and Processes, Vol 31, Iss 4-5, Pp 395-403 (2012) |
| ISSN: | 2191-0324 0334-6455 |
| DOI: | 10.1515/htmp-2012-0072 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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