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Nickel Plate Turns Black After Exposed to Water

We are currently having a problem with some nipples that are attached to a aluminium manifold in a cooling subsystem. The nipples are brass that have been nickel plated. After being left in tap water for several days then exposed to air the finish turns black.

Can someone please tell me what is happening here?

Bill Forsyth
- Westwood, Massachusetts
2001

Hi Bill.

You should not leave a nickel plated parts in a rinse for a couple of days because the rinse is not clean from contamination. If the nickel comes from a bright nickel solution, it's containing sulfuric from the brightener.

Regards,

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
2001

Bill,

Why would you leave nickel plated parts in tap water rinse for days? This might be whats causing you the problem in the first place.

Regards,

Joel Garcia
- McAllen, Texas
2001

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