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Title: Ab initio atomistic thermodynamics study on the oxidation mechanism of binary and ternary alloy surfaces

Utilizing a combination of ab initio density-functional theory and thermodynamics formalism, we have established the microscopic mechanisms for oxidation of the binary and ternary alloy surfaces and provided a clear explanation for the experimental results of the oxidation. We construct three-dimensional surface phase diagrams (SPDs) for oxygen adsorption on three different Nb-X(110) (X = Ti, Al or Si) binary alloy surfaces. On the basis of the obtained SPDs, we conclude a general microscopic mechanism for the thermodynamic oxidation, that is, under O-rich conditions, a uniform single-phase SPD (type I) and a nonuniform double-phase SPD (type II) correspond to the sustained complete selective oxidation and the non-sustained partial selective oxidation by adding the X element, respectively. Furthermore, by revealing the framework of thermodynamics for the oxidation mechanism of ternary alloys through the comparison of the surface energies of two separated binary alloys, we provide an understanding for the selective oxidation behavior of the Nb ternary alloy surfaces. Using these general microscopic mechanisms, one could predict the oxidation behavior of any binary and multi-component alloy surfaces based on thermodynamics considerations.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ; ;  [5]
  1. College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300387 (China)
  2. (China)
  3. Institute of Information Optics, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)
  4. Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States)
  5. Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)
Publication Date:
OSTI Identifier:
22416129
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; ALUMINIUM ALLOYS; BINARY ALLOY SYSTEMS; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; OXIDATION; OXYGEN; PHASE DIAGRAMS; SILICON ALLOYS; SURFACE ENERGY; SURFACES; TERNARY ALLOY SYSTEMS; THERMODYNAMICS; THREE-DIMENSIONAL CALCULATIONS; THREE-DIMENSIONAL LATTICES; TITANIUM ALLOYS