Anodizing Type II (Sulfuric)
Anodizing is a conversion of the aluminum surface to practically pure aluminum oxide; the anodic coating. Type II is of particular interest to the designer wishing to extol both the virtues of form and function.
This anodic coating is significantly more abrasion and corrosion resistant than the untreated metal. The coating thickness is a combination of both penetration and build-up, in approximately a 50-50 ratio. This coating may be subsequently dyed in a variety of colors, imparing a very decorative finish both in a satin and a polished surface result.
AMS 2472C listed as similar to this Spec, Type II, Class 2 (informational only). AMS 2471C listed as similar to this Spec, Type II Class 1 (informational only). Coatings can be colored with a large variety of dyes and pigments.
Conventional Types I IB and II are intrended to improve surface corrosion protection under severe service conditions or as a base for paint systems.
Type I and IB coating should be used on fatigue critical components (due to thinness of the coating). Type IC and IIB coatings provide non-Chromate alternatives to Type I and IB where corrosion, resistance, paint adhesion and fatigue resistance is required. Specify class of anodic coating and any special sealing requirements.