<i>Review:</i> Replacements for Chromium Pretreatments on Aluminum

Abstract

The use of chromium (Cr) as an anticorrosion pretreatment ingredient to protect aluminum (Al) alloys is being restricted because of environmental concerns. Research currently is under way to find environmentally compliant substitutes for Cr. While most work is directed toward developing new types of conversion and anodic oxide coatings, other schemes involving anodic spark deposition, rare-earth additives, tin oxide films, ion-beam and chemical vapor deposition, and various organic-based coatings also are being developed. This work reviewed published literature in the field of Cr replacements for protecting Al.