Role of Coating Defects and Substrate Heterogeneities in the Long- Term Performance of Painted Aluminum Alloys

摘要

This project seeks to understand the material, environmental, and interfacial factors that control the initiation and propagation of underpaint corrosion on aerospace aluminum alloys. The information needed to understand coating breakdown requires the use of local electrochemical, optical, and chemical methods. These methods have shown that intrinsic chemical heterogeneities most likely exist in the epoxy coating materials. These defects allow water and ions to the metal interface. The type and extent of subsequent underfilm corrosion is then determined by the type and possibly spacing of intermetallic compounds, as well as the ionic and material gating characteristics of the coating material.