Chemical Conversion

Conversion coatings is a generic term used to refer to a coating produced by a chemical or electrochemical treatment of a metallic surface that gives a superficial layer containing a compound of the metal. 

Chromate conversion coatings are a varying group that can be done as a stand-alone finish, used by itself, or as a secondary post finish treatment, used over a metal plating. Chemical Film on Aluminum, also called by proprietary names of Alodine or Iridate, is a thin, clear or yellow conversion coating used as a primer for paint, general protection to prevent aluminum from oxidizing, or used in conjunction with masking of an anodized finish for conductivity properties. 

Aluminum Chromate Conversion Coatings Features:

• Good base for paint applications
• Protects from corrosion
• Provides good electrical properties
• Easily applied
• Applied by brush in field as touch-up for damaged anodize or paint

What are the governing specifications that cover Aluminum Chemical Conversion?

• AMS 2473
• AMS 2474
• ASTM B 449
• ASTM B 921
• MIL DTL 5541