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Gold plating over nickel plating for outdoor application

February 17, 2010

Hi,

I'm with a N.Y. based electronics company. I hope someone has time to help me with a plating question.

I'm designing a package from 6061 Aluminum housing for outdoor use. We typically plate this type of part Electroless Ni .0001 to .0002" thick. This is a microwave product with a waveguide.

The Housing I'm working on is Aluminum. The waveguide part that bolts up to it is 360 series brass that is plated Electroless Ni .0001 to .0002" thick. There is a Au flash over the Ni.

Will I have a problem with Galvanic Corrosion bolting the Ni/Au plated brass part to the Ni plated Aluminum part.

Thanks,

Dan Sundberg
product designer - Stony Brook, New York

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February 18, 2010

Hello Dan,
I had to look the data up on a chart put out by Engineering Edge. For harsh environments (such as outdoors) there should not be more than 0.15 volts difference in the anodic index for the dissimilar metals. Nickel is 0.30 on the anodic index and gold is 0.00V, with the difference of course being 0.30V. Would it be possible to choose something more compatible like gold, graphite, zirconium? Hope this helps.

Mark Baker
process engineer - Malone, New York