Abstract
We assess two alloys, FeAl and Fe3Si, in terms of their ability to inhibit ingress of carbon into steels using periodic density functional theory to model alloy thin films. Absorption of carbon into Fe3Si via its (100) and (110) surfaces is predicted to be considerably more endothermic compared to absorption into FeAl or pure Fe. Predicted energy barriers for surface to subsurface diffusion are ∼1 eV or larger for all four surfaces studied. A very endothermic dissolution enthalpy (1.65 eV) and large diffusion activation energies (e.g., 1.29 eV) suggest Fe3Si should inhibit carbon uptake into bulk steel and slow bulk diffusion. Combined with the results of other recent work [Johnson, D. F.; Carter, E. A. Acta Mater. 2010, 58, 638], we expect that a protective coating of Fe3Si should be effective at preventing steel degradation by hydrogen and carbon containing gases
Original language | English (US) |
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Pages (from-to) | 4436-4444 |
Number of pages | 9 |
Journal | Journal of Physical Chemistry C |
Volume | 114 |
Issue number | 10 |
DOIs | |
State | Published - Mar 18 2010 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- General Energy
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films