plating, anodizing, & finishing Q&As since 1989
What alternatives are available for Chromate Coatings?
We have been instructed to stop using Chromate Conversion Coatings due to the environmental concerns of Hexavalent Chromium. We have been using Clear & Yellow Chromate Coatings on Aluminum parts for electrical conductivity. What alternatives do we have to replace this finish?Samusel Ferguson
- Newark, DE, USA
First of two simultaneous responses -- 2005
I gave a paper at SurFin 2004. "Conversion coatings for Aluminum and Magnesium". It includes non-chrome processes. The paper is available from AESF [www.nasf.org].
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [affil link to the book on: Amazon or AbeBooks ])
Second of two simultaneous responses -- 2005
You do have an alternative that gives you everything except the yellow color. The new products are based on trivalent chrome and meet or exceed the requirements of MIL-C-5541 and the conductivity test. This material has been in the works for a while now but until the pressure was put on by political and environmental groups changing wasn't eminent. Now things are really moving!
Drew Nosti, CEF
Ladson, South Carolina
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