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Dichromate corrosion protection

2002

I have some vertical steel mounting columns that HAVE A DICHROMATE COATING OVER NICKEL for corrosion protection. The color is very varied with different shades of green , dark yellow, light yellow, etc. They do not have a smooth color, or uniformity for better wording. Some pieces have shed like a light powdered yellow substance. Some is bubbling and chipping. A tape test peeled the material away, and left a silverish color. Please help me understand the finish and also is there some problem with the finish, or is this normal behavior? Can you send me information on specifications, process and standards for the chromium coated finishes on steel. The equipment is for industrial use.

Thanks,

R. Castro
- Miami, Florida

Hi R. I'm going to say these racks seem to be zinc plated and chromate conversion coated, rather than nickel plated. Would you accept that as the starting point for the discussion?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Ted is available for instant help
or longer-term assistance.
2002

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