Components are first chemically milled then chromated to give a dull almost olive drab finish. Chromate coatings are chemical conversion coatings. The substrate metal participates in the coating reaction and becomes a part of the coating. This has a profound effect on the corrosion properties of the coating, in excess of 96 hours to white corrosion. Special seals can be applied, which increase corrosion resistance to over 500 hours. Chromate films are typically very thin, around .0000001”, and contribute no measureable thickness to the overall coating.