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RoHS Compliance of clear and yellow Iridite aluminum finishes

Many of our electronic chassis and cabinets have yellow Iridite finishes for passivation and good electrical conductivity. Our painted, lettered front panels have clear Iridite coating for passivation and paint adhesion. Are these finishes RoHS compliant? Do they have any chromium content? What valence? If not RoHS compliant, what are the alternatives?

Robert Goldstein

2006

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It's probably a given that the chemistries used to produce your Iridite coatings are Hexavalent Chrome in nature. As has been document in other posts, these are NOT RoHS compliant.

There are several Non-Hex alternatives for Chemical Conversion Films on aluminum. The problem is that only one has thus far shown itself capable of passing the requirements set forth in Mil-DTL-81706. That chemical is a Trivalent Chromium Pretreatment developed by the US Navy and licensed to Sur-Tec International, Luster-On, Henkel Surface Technologies and Metalast. These licensed versions are currently in the final phase of testing for inclusion in Mil-QPL-81706. Of all the chemistries tested, this is the only on that will pass a "bare salt spray". Mil-C-5541 is in final stages of rewrite to provide for non-hexavalent based conversion films.

Justin Crisp

2007