Thread 22/33

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
publicly reply to Bud Kaiser

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1998

There sure is. Yellow chromate vastly outlasts clear chromate. See the MFSA "Quality Metal Finishing Guide to Zinc Plating".

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
publicly reply to Ted Mooney

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Clear chromate withstands 16-24 hours in neutral salt spray while yellow withstands 96 hours.

Sara Michaeli
Tel-Aviv-Yafo, Israel
1998
publicly reply to Sara Michaeli

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
1998
publicly reply to James Watts

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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
1999
publicly reply to Daniel Chaplin

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
2000
publicly reply to Anna Mayhew

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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.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
publicly reply to Ted Mooney

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