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Tin vs nickel plating

 

What is the resistivity of a tin plate vs a nickel plate over aluminum castings. I am looking for a cheap somewhat cosmetically appealing solution that must be conductive. The units will probably be plated over in the Orient, but I'm told that tin plating isn't very popular over there. I appreciate any input.

Thanks,

George Bonilla
- Camarillo, California, USA

If you are concerned about resistance, use gold. Slightly lesser is silver, but it tarnishes. With the thin coating of a plate, you would have to be into electronic circuits to make a difference. pure tin-11.1 microhm-cm electrodeposited nickel 6.84 to 11.49 depending on the bath used. Average is about 8.

James Watts
- Navarre, Florida

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Both tin and nickel are conductive, the cost of the preplate cycle for aluminum means that the cost of the coatings will probably be about the same. To what kind of atmosphere will this coating be exposed?

  
Tom Pullizzi
Falls Township, Pennsylvania

Why don't you ask the platers in the Orient? They will be plating the parts. Or perhaps with the money you saved by producing the parts in the Orient you could hire a consultant who advertises on this site.

Todd Osmolski
- Charlotte, North Carolina, USA

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Now that's just silly, Todd; platers in China don't know which of two platings will get them more conductivity. They only know that they will be getting two strokes of their owners' whip across their back in hopes of saving some consumer somewhere two cents.

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

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The specific conductivity of electroplated tin is about 11-14 micro-ohm-cm. The specific conductivity of electroplated nickel is about 8 micro-ohm-cm. (i.e. nickel is a better conductor than tin) Nickel provides better corrosion resistance than tin over aluminum, provided the deposit is pore free. Silver is the best conductor, but like tin does not provide corrosion protection. Both tin and silver will diffuse into aluminum, causing early failure of conductivity. If the surface condition is not decorative, nickel plate followed by silver (or electroless nciekl followed by silver would provide a long lasting conductive surface. )

Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
           and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])