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Passivation color

2004

Hi,

I am the Quality Assurance In-charge of a acid chloride zinc plating facility. We do rack plating of the components with a plating thickness of min.15 microns followed by yellow passivation. One of our new customer wants complete yellow passivation color on the component rather than a mixture of red and green colors. We use a dichromate based yellow passivation bath and are unable to give that yellow color to him. It will be helpful if we could know what we need to do to get maximum yellow color coverage on the component. Is the color related to the passivation bath parameters or rinsing and drying procedures?

Thanks,

J. Mathew
Manager,QA - Electroplating - Chennai, TamilNadu, India

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Dear J,

Your best bet will be to dip into waterbased lacquer straight after yellow passivation. This takes away the refection causing the rainbow colours.

Good luck!

Trudy Kastner
electroplating service - Durban, KZN, South Africa
2004

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Dipping into waterbased lacquer or a special oil based seal is the thing you need, but there's a big difference between such products. Try out different... Very important is the time of the dipping. It takes effect after 1/2 minute or so.

With best regards,

Dimitrije Stopar
plating - Maribor, Styria, Slovenia
2004

I read somewhere, proteins can be added to the dichromate solution to get clear yellow.

Keshava Prasad M
- Bangalore
2004