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Trivalent finish for aluminum
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I have a customer that wants us to provide his parts with Trivalent finish. This part is made from 5052H32 Aluminum. Is this possible to do? If not, are there any alternative suggestions?
RichardSheet metal fabrication - Cedar Rapids, IA, United States
+++++ Mil-C-5541 [link is to spec at TechStreet] chromate conversion coating of aluminum utilizes hexavalent chromium solutions. Due to concerns about hexavalent chromate an increasing number of suppliers offer proprietary trivalent treatments for aluminum or chrome-free treatments for aluminum. Many of finishing.com's supporting advertisers offer one or the other. They will probably contact you privately, or you can locate them with a little browsing of our Chemicals Directory.
Articles have been printed in the technical journals purporting to prove that these products are the equal of hexavalent chrome treatments although some disagree.
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
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Chem. film has been around for years it is used to protect and /or prepare aluminum for painting. The most successful ones were patterned after Iridite or Alodine which are a trade marked names and contain hex chrome. Until recently trivalent chromates generally had little success replacing these materials. There is now a group of products that compare favorably with the hex chem. films. These should shortly be on the QPL list and meets or exceeds the requirements of MIL-C-5541.
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Drew Nosti, CEF Ladson, South Carolina |
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You can find very good free informations on next web page:
www.aluminum.org/TALAT/lectures/5202.pdf
Good luck!
- Zagreb, Croatia
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The link you gave us does not work can you provide a better address.
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Drew Nosti, CEF Ladson, South Carolina |
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You are right, You must use next address:www.aluminium.org
Then click on education and find conversion coatings lecture. Good luck!
- Zagreb, Croatia
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I'm with Drew. Spent 15 minutes twice now and I don't think it's there anymore.
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
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This link will get you there
http://www.aluminium.org/education/TALAT/lectures/5202.pdf
- Chennai, India
Ed. note: Thanks for the info. As long as this thread is becoming a page of links to reports on non-hex aluminum treatments, here's a couple more:
New Zealand Trade and Enterprise Group
(www.electronicssouth.com/index.cfm/RoHS%20and%20WEEE/Files/Cr6%20interim%20report), Interim Report on RoHS compliant alternatives to Hexavalent Chromium for Steel and Aluminium
ESTCP Phase I Report
(www.electronicssouth.com/index.cfm/RoHS%20and%20WEEE/Files/USA%20DOD%20Non%20chromate%20alternatives">Non-Chromate Aluminum Pretreatments)