you can have in metal finishing.
Clear vs. Yellow Chromate
(1998)
Is there any research on a comparison of zinc plating with different chromates?
(Clear vs. Yellow )
Thank you
Bud Kaiser
There sure is. Yellow chromate vastly outlasts clear chromate. See the MFSA "Quality Metal Finishing Guide to Zinc Plating".
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey
(1998)
Clear chromate withstands 16-24 hours in neutral salt spray while yellow withstands 96 hours.
Sara Michaeli
chemical process supplier
Tel-Aviv, Israel
(1998)
Olive drab is the most resistant common chromate with no additional treatment. A lot depends on the operator of the plating line as to what actual production parts really get for hours in the salt spray cabinet, which has a poor relationship as to how it relates to actual use conditions.
James Watts- Navarre, Florida
(1999)
There are a new breed of trivalent blue passivates which will provide extended corrosion resistance. When compared to yellow passivation they stand up very well.
Daniel Chaplin(2000)
I just finished an extensive study on film coatings on fasteners. The result of the yellow chromate was that it was far better than clear in many different chemical attacks followed by Salt spay tests. If a clear coating is preferred, the JS series is yellow chromate bleached back to clear. This JS series topped all resistance to chemical attack as well as mechanical durability.
Anna Mayhew- Wisconsin
April 24, 2008
Hi, readers. 1998-2000 was a long time ago in terms of chromating. Probably the majority of chromating done today is trivalent. And in this case the yellow color is just dye which does not enhance the corrosion resistance but may slightly reduce it.
Regards,
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey
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