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Coloring of metal parts without using chromates

2004

Hello!

I am wondering if you know a method of adding color to small steel parts which can replace the zinc plating + colored chromate method.

We need to get rid of chromates due to toxicity requirements so I need to find an alternative method.

Thanks!

Francisco Franco
automotive engineer - Mexico

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You still need the zinc plating for corrosion protection, so what you might want is zinc plating with trivalent chromate and dye, or possibly electrophoretic lacquer. Why are you dyeing the parts?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

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Hi Ted, You are right, we will keep the Zinc plating and change from hex to trivalent chromate. The issue we have is that we need to have the part with a color different from the Trivalent silver because our manufacturing operation uses colors to differentiate the parts and avoid mixing. Is it possible to color the trivalent chromate? Our supplier keeps telling us that it is not feasible...

Regards from Chihuahua Mexico. Francisco

Francisco Franco
Visteon - Mexico
2004

Trivalent chromate films may be readily dyed if the film thickenss is adequate. For this you should use a chromate which is designed as a "yellow replacement" or a trivalent specifically designed for dye acceptance. Also one of the trivalents on the market exhibits a greenish tint in normal application

Gene Packman
process supplier - Great Neck, New York
2004

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In reference to the above subject I would like to know is it possible to add colours on silver plated copper wires by this colored chromate method and which dyes are used for this process, I would like to have different colours added on silver plated copper wires and want to use for decorative purpose. I would also like to know what is Trivalent Chromate.

Regards.

Dhiren Patel
- Ahmedabad
2005