Metal finishing Q&As since 1989

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Rusting on trivalent chrome plating

Can anybody tell the reason, why the metal parts getting rust after trivalent chrome plating with blue passivation? What precautions to be made to protect from rust? These parts are made at India & sent to UK.
G. Ravichandran
Molded components with assy for Electrical industries - Ahmednagar, Maharashtra, India
2006

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Passivation is not done on chrome plated parts, G., so I assume that you are not actually speaking of trivalent chrome plating, but rather of zinc plating with a trivalent chrome conversion coating? If the components are rusting it is because the parts were not dried properly, or are not properly packaged for shipping, or the plating plating process is not as robust as required. Please describe the component, the complete plating specification, and how they are packaged for shipment. Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

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2006

Mr Ravichandran

The question is very broad. You have zinc plated , trivalent blue chromated parts failing earlier in Corrosion testing than these should.

I suggest your plating vendor goes in for a proper audit first with a third party as supervisor to find out the cause first.

Thereafter you can have remedial measures implemented within your reach.

For your info, properly treated , correctly applied, Trivalent Blue chromated parts withstand from 76 to 180 hours in Accelerated corrosion tests. In India not far from Ahmednagar...

Regards,

Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016