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Contacts

 

There are 2 small contacts - one a Ni plated steel and the other Galvanic Ni plated SS. It becomes insulating after a period of usuage of the product. After wiping the surface with an organic solvent, it starts functioning for again a definite period of time.What may be the reason? Ni plating is non porous.

Nagalakshmi Thogulava
- Noida, Uttar Pradesh, India

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The study of electrical contact surfaces is perhaps a bit broad to cover in a paragraph here, but nickel tarnishes and is suitable for medium voltages but not really low voltages. Look at the contacts on your computer, cell phone, etc.: note that for non-critical battery contacts, nickel usually suffices but that the contacts for digital information exchange are gold plated. What kind of signal are you trying to carry?

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

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Is it possible to selectively gold plate on a small Ni plated area (1mm x 5 mm) surface for providing good contacts as well as prevent corrosion? Compoent cannot be exposed to more than 45 °C.

Nagalakshmi Thogulava
- India
 

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Ted,

Thanks a lot for your response.The contacts are carrying a 3V, 1.2 microampere signal from a 3V button cell. Do you think Ni plating can carry this signal without oxidising? Also, I have seen some parts of the positive contacts having porosity in the Ni plating. These parts didn't have this problem when it was chemical Ni plated.

Nagalakshmi Thogulava
- India