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Electrically Conductive Coating for C26000 Brass

July 27, 2009

We are currently having a problem with sulfur-induced oxidation on a C26000 pin for our connector. Oxidation is building up at such a fast rate that the built-in mechanical removal methods of the connector cannot keep up (in this case Amphenol's Radsok technology). We know its sulfur as the oxide has been analyzed.

I was wondering if there were any coatings/platings that may be added to improve this situation. I already understand that silver plating is probably a no-go as it tarnishes readily when exposed to sulfur in its many forms.

Specifically I would be interested in a clear electrically conductive plastic (like a lacquer).

Brent Johnston
Product Designer - Burnaby, BC, Canada

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I'd suggest you consider titanium nitride. It is quite inert, electrically conductive, and should provide corrosion resistance. The color is dark gold, not far removed from polished brass. It is also far harder than the brass, so the pins should hold up better.

If titanium nitride does not stop the corrosion, you may want to look at zirconium nitride, a very similar coating, but lighter gold color. In ASTM B117 salt fog tests on carbon steel it provided corrosion resistance out to 24 hours, quite remarkable for a thin coating full of pores. Titanium nitride-coated samples failed in a few hours. For reference, uncoated carbon steel is completely covered in rust in less than one hour.

Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
August 5, 2009

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Dear Mr Brent,

White Bronze plating comes to mind. Mostly inert to bimetallic corrosion and does not tarnish like Silver. One micron of Bronze is sometimes used as a final topcoat over Silver plating to keep Silver Plating from Tarnishing.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

August 25, 2009