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Is phosphate coat on zinc plating RoHS compliant?

My company has been having paint adhesion issues with CRS that is zinc plated with a clear trivalent chromate coating. I've read on this website and others that a phosphate coating is best for painting, but want to make sure it's RoHS compliant first. We are using polyurethane paint. I have not found any information directly related to the phosphate coating and RoHS, can someone enlighten me please? Thanks.

Miek Huppert
- Poway, California, USA
2006

In all probability it will be RoHS compliant, you need to talk to some zinc phosphating suppliers just to make sure. The component that tends to be non-RoHS compliant tends to be the seal after phosphating. You are powder coating next so this operation isn't really necessary.

Brian Terry
Aerospace - Yeovil, Somerset, UK
2006

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Brian makes an excellent point that it is important to check with suppliers on the RoHS issue because there can sometimes be ingredients in a process that the uninitiated might not suspect. It's a little off-topic to serve as a particularly good example for phosphating but, as a for-instance, traditional electroless nickel plating contains lead and cadmium and is not RoHS compliant unless reformulated to be so. So take the precaution of checking with the supplier before assuming that there are no RoHS prohibited materials in it.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Need quick confidential answers? $25
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2006

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