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Stain over nickel plated brass components

We do Nickel plating over brass connector components. After rinsing and drying, we observe the parts get stained within few ours. Can some one help to prevent this always and also ways to remove the stain from the stained parts.

DHANASEKAR. D
Connector Manufacturer - CHENNAI, TAMIL NADU, INDIA
2004

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The part is probably staining because the nickel is too porous. The easiest way to rectify this is often to increase the thickness. How thick is the plating?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

The thickness of nickel is between 4 and 6 microns. And would like to know the optimum thickness of nickel, at which there shouldn't be any pores in the layer. Can any one suggest the methods to find out the porosity in the nickel layer.

DHANASEKAR. D
- Chennai, Tamil Nadu and India
2004

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The Metal Finishing Guidebook explains easy porosity tests. Safranek's Properties of Electrodeposited Metals and Alloys [affil link to Amazon or on AbeBooks] says: "5 micron nickel is nonporous on polished smooth copper, whereas steel finished with 240-grit paper requires 25 to 30 microns..."

Assuming you are talking about stains due to porosity rather than salty rinse water, it seems that you need to improve the finish on the connectors and/or increase the thickness at least 25 percent to reach accepted standards.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004