Metal finishing Q&As since 1989
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Parts w/ yellow chromate losing color
I had a similar question. I am working with a client who is using Yellow Chromatized panels in a lobby scenario. The panel that was originally supplied and left in an interior office for viewing seems to have lost the original shine and reflectivity that it had.
Is there a cure or set time where this naturally happens and is to be expected.
It is an overall loss in shine and not something limited to an area where handling could have happened
A new panel that we recently chromatized has the shine pop and reflectivity that the previous panel started with.
- New York, New York
June 28, 2021
A. Hi Bill. First things first for the readers, even if you already know it: yellow chromate on zinc plating is a functional finish, not a decorative finish.
If it's coming out at various colors and saturations, or the color isn't lasting, but you haven't required aesthetic compliance with sample boards, you are in a weak position. As long as it passes the required corrosion or other tests, it's satisfactory whether you like the look or not. Anodized aluminum with a yellow/gold dye, or stainless steel with a titanium nitride PVD seems more likely to meet your aesthetic requirements.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2021
⇩ Closely related postings, oldest first ⇩
Q. We make parts which get a zinc plated w/ yellow chromate. The yellow chromate appears to be rubbing off or losing brightness & color, in subsequent operations after plating. (light handling in oil amp;& solvent) Is this typical with yellow chromate? Can this potentially affect corrosion resistance or is this strictly a cosmetic issue.
Ken MartinJob Shop - Hillside, IL, USA
2004
A. The yellow chromate coating is thin and soft, so can be damaged in handling. Yes, the corrosion resistance is impaired if the chromate is rubbed through.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
2004
A. We had a similar issue where chromate could be rubbed of with light handling or just by rubbing your finger. We traced this to excessive amount of brightener in the zinc tank, once we were able to bring it to a lower level everything seemed to be working fine. Now we use a soft eraser to check this condition, if the chromate holds well after five or six strokes we are pretty sure it will be there for long.
Saludos
- Mexico City, Mexico
2004
Production Manager for Plating Co. - AST, Arvada, CO
Junior Sales Representative - Resintech, Camden, NJ
Nadcap Chemical Processing Auditor - PRI, traveling
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