Effects of Alloying on the Chemistry of CO and H2S on Fe Surfaces
Abstract
Deleterious gases such as CO and H2S can cause degradation of steel by reacting with the metal surface. Here we consider whether alloying the steel surface might be able to inhibit these damaging surface reactions by raising the barriers to molecular dissociation. We employ first-principles density functional theory techniques to investigate the elementary reaction pathways and barriers for CO and H2S on FeAl and Fe3Si surfaces and compare them with pure Fe surfaces (as a model for steel). We find that H2S dissociates on iron surfaces much more easily than CO does. Although FeAl surfaces raise the barriers for H2S dissociation, they significantly lower the barriers for CO dissociation. On the other hand, Fe3Si surfaces raise the barriers for CO dissociation, but they are as vulnerable as Fe surfaces to H2S dissociation. Our findings suggest that alloying iron with Al or Si is unlikely to simultaneously increase its resistance to the initial stages of chemical degradation by CO and H2S.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2005
- Accession Number
- ADA459083
Entities
People
- D. E. Jiang
- Emily A. Carter
Organizations
- Princeton University