Iridite Clear (Chem Film – DTL-5541 Type II)

Iridite (clear), also known as chromate conversion coating or “chem-film”, is a protective film applied to aluminum and its alloys. It is sometimes referred to as “aluminescent”. All Type II refers to clear coating and does not contain hex-chrome. Here are the key points:

               Purpose:

                               Provides corrosion protection.

                               Acts as an adhesion promoter for paint or adhesive bonding.

                               Conductive (typically no more than 5 milliohm resistance).

                               Coating thickness: 10-40 millionths of an inch.

               Process:

                               RoHS and WEEE compliant.

                               Application methods: dip, brush, swab, or spray.

                               The coatings range from clear to dark yellow (Clear is ROHS compliant) .

               Regulations:

                               Iridite NCP and Alodine 5200 are hexavalent-chrome-free alternatives.

                               Used in auto industry (brake calipers, electrical components) and aerospace (paint and primer application).

               Specifications:

Class 1A provides maximum protection against corrosion, whether painted or unpainted. Class 3 provides protection where low electrical resistance is required. In the case of Type 1, Class A, the appearance will be more yellowish, and Class 3 will be almost clear in appearance.

                               MIL-DTL-5541 (formerly MIL-C-5541)

                               ASTM B921 (Non-Hexavalent)

                               AMS 2473 (General Purpose Applications)

                               AMS 2474 (Low Electrical Resistance Applications).