Mechanisms of Aqueous Corrosion of Aluminum at 100°C

Various alloys of Al, as well as superpurity Al material, have been tested in aqueous solutions at 100°C. Samples have been polarized cathodically and anodically to study the effect of cathodic and anodic reactions, respectively, on the corrosion behavior. Results are interpreted as showing that the alkalinity produced at the cathodes facilitates film breakdown in these places. Consequently, alloys containing cathodic constituents were attacked where these constituents were situated, while polycrystalline superpurity material was attacked in the grain boundaries. The influence of bulk p H and inhibitors is discussed in some detail.