Metal finishing Q&As since 1989

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Can I get yellow color with a trivalent chromate

 

We've got some samples of zinc plated pieces chromated with a trivalent chromate. We requested a yellow chromate but they came in white. The supplier says that maybe with the new trivelnt chromate that is the color he got. Does the trivalent chrome affect if it's possible or not to get a yellow chromate. Hope you can help me.

Thanks and my best regards.

Guillermo Castorena
- Sn Luis Potosi, Mexico

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Most all trivalent chromates that work are clear/silver colored. Some companies are offering trivalent yellows, but they accomplish this by adding a yellow dye. A dye may or may not be acceptable for your application. I have encounted a few claims of a true yellow trivalent chromate, but have not tested or evaluated any.

If you are in the automotive industry, do yourself a favor and stay with trivalent. Do not go to hexavalent on new programs unless you want a big headache 6 months from now.

Tim Neveau
Rochester Hills, Michigan

The trivalent chromates are not yellow. We process many parts with trivalent chromate, with a light blue color. We are performing tests with a yellow trivalent chromate and a post finish, and they look very good.

Carlos Cielak
plating shop - Mexico City, DF, Mexico