Chromate conversion coatings and chromated sealers are used to create a self-healing conversion coating on Al and Mg alloys that is resistant to corrosion. They are also used for sealing electroplated and anodized coatings. These treatments are typically used prior to painting and finishing, since they generally improve adhesion of paints and sealants.
Typical Chromate Conversion Coatings
Cr6+ (CrVI, hexavalent chromium) is a known carcinogen that is strongly regulated under
Exposure Personnel may be exposed during manufacture, depot overhaul, repaint, and operational level touch-up and repair.
Alternatives, Applications, Status
Primary alternatives are Cr3+ (CrIII, trivalent chromium) and non-chrome products (Mo, Mn, rare earth, and other inhibitors). Alternatives are commercially available and some have been authorized and implemented.
Examples of Authorizations and Implementations
Adhesion promoters, sol gels, silanes