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-----Interested in alternatives to yellow chromate on our zinc plating
Can you advise the minimum Hexa chrome used in passivation as in Zinc and Yellow Pass in terms of micrograms per sq centimeter - we use this plating for metal chassis and are being advised this will become a forbidden substance over .01 ug/cm2 by 2003. is there an alternative?
Mr Geoff Bearpark- Havant Hants, UK
2001
You need to replace your yellow hexavalent chromate bath with a clear trivalent chromate bath. This type of chemistry is offered by a variety of plating chemical suppliers.
Tim Neveau
Rochester Hills, Michigan
2001
I have seen and tested yellow hex chrome free coatings. Excellent salt spray resistance still no red rust at 648 hrs ASTM B117 testing.
Brian Lucas- Wolcott, Connecticut
2001
Under the right conditions a cheap paint job will give better salt spray performance than a hexavalent chromate conversion coating. So, what is making the coating yellow if it has no hexavalent chromium? The issues go together because if the coating is conductive, and if scratching up the finish causes no significant reduction in salt spray performance, I'm very much impressed! But if the coating is related to a tinted lacquer of any sort, well, then Shania Twain said it better than I can.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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2001
Film weight of zinc and yellow passivate is 12mg per square decimeter of which 70% is Cr6. I don't have the weight for blue/clear passivate but it will obviously be somewhat lower than that figure.
Dougie Lightfoot- Fife, Scotland
2001
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