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Yellow chromate doesn't look like full gold

We always get customer complaints for surface colour after yellow chromate. Recently the customer thinks that the treated surface should have full yellow, but the product we provide always appears a little red tint.Who can tell me what colour the normal yellow chromate should have? thank you in advance

Paul He
Quality engineer - DongGuang, Guangdong, China
March 30, 2010

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March 30, 2010

Hi, Paul. Yellow chromate is not a decorative finish and happens to look generally yellowish because that is the natural color of hexavalent chromate. Switch to a RoHS-compliant chromate and it will require dye to give it the yellowish color. The dye probably won't have as much red in it.

Regards,

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

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I have used 2 different proprietary chem film solution. One starts out as a pale yellow and proceeds to a dark yellow with time in the tank.
The other one starts out as a light yellow and proceeds to a rust orange with time in the tank. Both are fully compliant with the specifications. This solution needs to be watched a bit closer than the first one to get a color that most customers want.
I switched from the first company to the second company because of a quality problem that they did not fix.
Play with pH, time temperatures and concentration and see if you can not get an acceptable color with your current material.
PS: do not over etch the parts.

James Watts
- Navarre, Florida
March 30, 2010

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Hi,

The best way is to yellow dye the components after the passivation, it works well and has uniform yellow colour all over.

Regards

Praveen Kumar
plating process supplier
Mumbai, India
April 8, 2010