Abstract
Upon oxidation, a silica scale forms on , a potential high-temperature coating material for metals. This silica scale protects against high-temperature corrosive gases or liquids. We use periodic density functional theory to examine the interface between and . The interfacial bonding is localized, as evidenced by an adhesion energy that changes only slightly with the thickness of the layer. Moreover, the adhesion energy displays a relatively large variation with the relative lateral position of the and lattices due to changes in bonding across the interface. The most stable interfacial structure yields an ideal work of adhesion of within the local density approximation ( within the generalized-gradient approximation) to electron exchange and correlation, indicating extremely strong adhesion. Local densities of states and electron density difference plots demonstrate that the interfacial bonds are covalent in character. interactions are not found in the interface investigated here. Our work predicts that the scale strongly adheres to , and further supports the potential of as a high-temperature structural material and coating.
- Received 17 May 2005
DOI:https://doi.org/10.1103/PhysRevB.72.165410
©2005 American Physical Society