Mil-C- 5541

Anodize Type I Anodize Type II Anodize Type III
Chem Film MIL – C – 5541
Passivate QQ-P-35
Monthly Test Reports

The Military Specification referred to as MIL-DTL-5541, "Military Specification, Chemical Conversion Coatings on Aluminum and Aluminum Alloys" covers chemical conversion coatings formed by the reaction of chemical conversion materials with the surfaces of aluminum and aluminum alloys. The current specification (2009) is MIL-DTL-5541F, which superseded MIL-C-5541E in July 2006. The specification is approved for use by all departments and agencies of the United States Department of Defense (DoD). Although prepared specifically for DoD applications, the standard is used for many commercial applications as well.

The MIL-DTL-5541 specification covers chemical conversion coatings that form protective coatings by chemical reaction with aluminum and aluminum alloy; these coatings are categorized by the following types and classes.

Type I: Addresses compositions containing hexavalent chromium.
Type II: Addresses compositions containing no hexavalent chromium.
AND

Class 1A: Provides maximum protection against corrosion, whether painted or unpainted. This is a relatively thick film used as a final finish or pre-treatment to paint or powder coating, and it is typically gold, brown, or yellow depending on coating weight and alloy.
Class 3: Provides protection against corrosion where low electrical resistance is required. This is a thin film providing low contact resistance, and the coating weight is lower as is the corrosion resistance. There may be some advantages using this thinner film in bonding applications. This film typically appears to be a lighter color of gold.

Mil-C-5541, Class I A , 3 — Mil-DTL-5541 Type I, II Class IA, 3
AMS 2473
•        Type I , Class IA – Coating Yellow In Appearance - Maximum Corrosion Resistance
•        Type I , Class 3 – Coating Clear or Yellow in Appearance
•        Type II, Class 3 – Coating Clear – RoHS Compliant
•        Conductive Coating
•        Excellent Base Or Primer For Painting