Chromate Conversion

DeKalb Metal Finishing uses chromate conversion coatings to treat aluminum. The process uses various chromium compounds which may include hexavalent chromium. Less toxic alternatives are being developed in order to comply with substance restriction legislation.
Chromate conversion is often used as a primer for subsequent coatings and is especially important in the aircraft industry as untreated aluminum is very difficult to paint or glue. Chromated parts retain their electrical conductivity to varying degrees. The process may be used to add color for decorative or identification purposes.

Chromate coatings are soft and gelatinous when first applied but harden and become hydrophobic as they age. The thickness of coatings varies from a few nanometers to several hundred nanometers.

Estimated Salt Spray Results = 96 hours to white oxidation