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Gold brush over Electroless Nickel on C14500

2005

I have a rather large component machined from half hard Te-Cu (C14500). To provide resistance to tarnishing I plan to EN plate the entire device. I expect that Electroless Nickel per MIL-C-26074 [on DLA], Class 1, 4.0 - 7.0 µm will be acceptable as I have seen this spec'ed on other postings for Te-Cu. To improve electrical conductivity I plan to perform a subsequent gold plate operation. My investigation has revealed few or no local plating suppliers that have a gold tank large enough to plate my entire part. I am therefore considering brush gold plating the specific areas which require the improved conductivity.
My questions:
1)As the part has taken a long time to machine and has begun to discolor/tarnish - do I need to specify any pre-EN plating processing to optimize the EN process or results?
2)If so what exactly should I specify for this "cleaning" process.
3)What/How exactly should I specify for this brush gold plating process, thickness, etc?

Danny Hlavinnka
Mechanical Engineer - Houstin, Texas

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First of two simultaneous responses --

I don't know the shape of your part but brush plating is not a good option to completely plate an irregular object. It is intended for simple geometries, rather small areas or touch up repairs. I would suggest that you find and negotiate with a plating shop that has an acid gold process tank big enough to immerse your part and that also has the electroless nickel process required. There should be no delay when proceeding from one tank to the next. Otherwise failure is almost sure.

Guillermo Marrufo
Monterrey, NL, Mexico
2005

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Second of two simultaneous responses -- 2005

Hello Danny,

I am not sure as to the issues surrounding the best method of cleaning and preparing the part for e-nickel.

What I can provide you is answers regarding brush gold plating. Brush gold electroplating is used in many industries and like any plating application we would need to know: Type(purity) Grade (hardness)and Class (thickness) We would also require the surface dimensions and were the part is to be plated. Brush plating is a portable process and can be brought on site rather than sending the part to the plating house if this is more beneficial.

Good luck and feel free to call me.

Chris Helwig
- Valencia, California