HEX Free Chem Films

Conversion Coating Process for Aluminum

Alpine Products and Metal Finishing Company located in Dayton, Ohio introduces our latest process.

Mil-DTL-5541 Type 2

Individuals long associated with the metal finishing industry immediately recognize the terms Iriditing and Alodining as nicknames for a process protecting aluminum with a yellow chromate conversion coating.  The terms stem from the two most prominent proprietary products, Iridite and Alodine, of aluminum finishing since its inception in the early 1950s.   However, recent European Union Directives such as End-of-Life Vehicles (ELV) approved in 2000, Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) both approved in 2003, now place restrictions on traditional hexavalent chromium containing finishes. The proposed OSHA limitation on hexavalent chromium exposure of 0.1 mg/m3, presently under review, has the American metal finishing and electroplating industries deeply concerned over the future of hexavalent bearing chemistries of any kind.  The combination of these new governmental policies creates a need for a replacement of hexavalent chromium based finishes with technology that rivals the performance but remains hexchrome-free.  This need has created the new name in chemical conversion coating technology.  

Alpine currently uses Alodine T 5900, which is a complex trivalent chromium conversion coating formulated for treating aluminum and its alloys. The process provides bare ASTM-B-117 salt spray resistance and it also serves as an excellent base for organic finishes and adhesives. Both the product itself and the conversion coating developed by Henkel Alodine T 5900 do not contain Hexavalent Chromium.