NPFC - MIL-A-8625
ANODIC COATINGS FOR ALUMINUM AND ALUMINUM ALLOYS
|Publication Date:||25 April 1988|
This specification covers the requirements for four types and two classes of electrolytically formed anodic coatings on aluminum and aluminum alloys for non-architectural applications.
Types I, IB and II. The conventional Types I, IB and II anodic coatings are intended to improve surface corrosion protection under severe service conditions or as a base for paint systems.... View More
Types I, IB and II. The conventional Types I, IB and II anodic coatings are intended to improve surface corrosion protection under severe service conditions or as a base for paint systems. Anodic coatings can be colored with a large variety of dyes and pigments. Types I, IB and II coatings provide better corrosion protection at higher cost than the chromate chemical conversion systems (MIL-C-5541). Repair of mechanically damaged areas by the use of materials conforming to MIL-C-81706, (see 3.3.4), will not restore abrasion resistance but will provide an effective means of reestablishing corrosion resistance.
Type III. Type III coatings are intended to provide wear and abrasion resistance surfaces with improved corrosion protection due to greater thickness and weight than the conventional anodic coatings. Sealing of Type III coatings is not recommended unless corrosion resistance is also a factor. Wear resistance is reduced by sealing. Anodic coatings form an excellent base for most types of paint systems, adhesives and dry film lubricants. Hard coatings may reduce fatigue strength. These factors should be considered in proposed use of parts subjected to cyclic loads. Generally, these hard coatings should not be used on parts or portions of parts which normally during rework would require restoring of dimensional tolerances because of wear of hard coated surfaces.View Less