MIL-DTL-5541F Type I, Class 1A or 3, Yellow Chromate Conversion
Also referred to by trade names such as Chemtreat, Chemfilm, Iridite® and Alodine®).
Yellow Chromate Conversion is a procedure that chemically applies a protective coating on aluminum through immersion.
The two classes of Chromate Conversion:
Class 1A coatings are thicker and intended to provide better corrosion prevention when left unpainted as well as to improve adhesion of paint finish systems on aluminum alloys.
Class 3 coatings are intended for use as a corrosion preventative film for electrical and electronic applications where lower electrical resistance is needed or required.
The benefits to chemically treating aluminum:
- Good corrosion protection
- Conductive surface
- Good primer for painting
- Adds no weight
- Maintains pre-process dimensions