Abstract
The effect of capillarity on the chemical equilibrium between a dissolved metal cation and the corresponding metal oxide is determined within the framework of Gibbssian thermodynamics. We examined the equilibrium between Cr3+ and Cr2O3 and found that for 10−6 M Cr3+ in the electrolyte and a curvature of −2 × 109 m−1, the equilibrium pH is −1.8. The corresponding potential-pH diagram shows that chromium passivates in strong acids. This analysis potentially resolves a long-standing issue in corrosion science.
Funder
Office of Naval Research
National Science Foundation
Publisher
The Electrochemical Society
Subject
Materials Chemistry,Electrochemistry,Surfaces, Coatings and Films,Condensed Matter Physics,Renewable Energy, Sustainability and the Environment,Electronic, Optical and Magnetic Materials