READINESS OF TRIVALENT CHROMIUM CONVERSION COATINGS FOR ALUMINUM ALLOYS

摘要

A field usable trivalent chromium conversion coating process for aluminum alloys was developed. A concentrate formulation was developed that can be mixed in the field and is ready for immediate use. The conversion coatings impart excellent paint adhesion and corrosion protection to A12024-T3 and AI7075-T6. Surface analysis reveals the conversion coating to consist of a mixture zirconium and chromium oxide species. Toxicological testing has confirmed that the trivalent conversion coating materials are much more benign than chromate (hexavalent chromium) conversion coating materials.