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Red spots on gold plating

Hello,

I am QA manager at a machine shop in the Bay Area. Pleased to meet you all!

I am trying to find the source of red spots that showed up on some parts at a customer site.

The gold finish on the parts looks fine, and the red spots were not there at the point of shipment. We also purged stock that had been inspected 100% originally, and a few from the same batch as the returns also showed red splotches. It looks like a few had marks around where the part would hang from metal racks, and the splattered on the inside and outside. Some very small, some large.

Does anyone have experience with this?

Leona Kingswood
defect analysis - Hayward, California, USA
June 30, 2011

any idea of the substrate?

Daniel Hernandez
- Bucaramanga Santander Colombia
July 7, 2011

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Hi
It is due to porosity.
Reasons: low gold thickness, base metal not processed, leftover burr if machined items, plating prior to gold (if there) is of less thickness, if copper is the base, then lack of a barrier layer!
If you want more suggestions, please post details of base metal, item, process detail and ...all!

T.K. Mohan
plating process supplier - Mumbai, India
August 6, 2011