wolkerstorfer metal finishing

MIL-DTL-5541

The most popular of the specifications for Chemical Conversion Coatings for aluminum. There are two “Types” and two “Classes” that can be designated. Type I has hexavalent chrome in it and Type II has trivalent chrome. The Class 1A is designed for maximum corrosion protection while the Class 3 is called out in applications where low electrical resistance is the primary function and/or RoHS compliance is required.