MIL-A-8625

Class 1 – Non Dyed
Class 2 – With Colored Dye
Hard Coat anodizing on aluminum alloys produces a hard and dense finish. It is an aluminum oxide coating, which provides good abrasion resistance, dry electrical insulation and also provides excellent corrosion resistance. Tests indicate that the hardness of this finish is about that of nitrided steel or file-hard, about 65 Rockwell on the C scale. The standard thickness is 1.5 to 2.5 mils, approximately one-half surface build up and one-half material penetration.