The Influence of Chlorine In Corrosion Initiation on Alumina Using A Cluster Model: A First-Principles Study*

The US spends more than $100 billion annually to address the problem of corrosion.  As even a modest reduction in corrosion has the potential to save billions of dollars each year, there is significant benefit to a rigorous understanding of corrosion initiation.  This work uses an ab-initio approach via Density Functional Theory to explore the onset of localized corrosion by investigating the stability of alumina film in the presence of halides.  

A cluster model is used to expose a variety of local environments which may be present on the surface of alpha-Al₂O₃.  Nanoclusters of several sizes were used to generate a range of potential environments for chlorine adsorption, offering insight into chlorine adsorption on dissolving and repassivating alumina films from relatively few simulations.  This work provides a structural and electronic description of the preferred chlorine adsorption environment and the initial system response.  Preliminary results reinforce the link between chlorine adsorption and under-coordination, with further structural analyses ongoing.  Additional in-progress including Projected Density of States calculations describes the electronic environment present during adsorption.