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Contamination on Gold Plated Connector Pins

I've read about gold plated pins being contaminated or corroded due to insufficient Nickel plating thickness. Could the contamination be due to other factors like chemical solutions (e.g., IPA) if the parts were subjected to washing process?

Neo Qwee Huat
Electronics manufacturing - Singapore
2006

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First of two simultaneous responses --

What you have read regarding insufficient diffusion barrier thickness such as the nickel plate is true. Purity of the gold deposit is another factor. Your question on the parts being subjected to washing causing problems, as long as all rinsing is adequate I doubt it. Hot DI water rinses work well after gold plate and drag-out.

Mark Baker
Process Engineer - Syracuse, New York
2006

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Second of two simultaneous responses --

IPA used to clean off tape residue, fingerprint, etc on gold deposit surface and should not attack gold deposit.

Acidic chemistries like nitric acid could attack underlying nickel thru gold porosity and cause dark spots on gold deposit.

Besides chemical attack thru gold porosity, metallic contamination in gold bath such as copper and iron will also cause co-deposit of metallic in gold deposit which will turn gold into reddish or brownish color after storage.

David Shiu
- Singapore
2006