Conductive Coatings for Brass and Copper
A discussion started in 1998 but continuing through 2018(1998)
Q. We are a low voltage lighting manufacturer.
We sell various track plated in nickel, copper and brass that is charged with 12 volts. The material plated is aluminum. We also have a brass track that we plate in copper and nickel. We no problems with the nickel plated tracks.
This is the problem (or excuse me) challenge:
The track needs to conduct electricity (12V) over the entire plated surface. This presents a problem with the copper and brass finishes. Without lacquering the track of course it tarnishes. If we lacquer the track it is the not conductive.
We are able to get around this where each fixture grips the track. A brass cone pointed set screw cuts through the lacquer to the conductive plated aluminum. This screw is able to conduct the small amount of power needed to power the single 50w bulb. The problem is at the power feed that feeds the entire track.
Is there a brite decorative conductive COPPER plating that will not tarnish? Without using a lacquer.
Is there a brite decorative conductive BRASS plating that will not tarnish? Without using a lacquer.
Is there a conductive coating that can be apllied to protect the plating (in place of a lacquer)?
- San Carlos, California
A. I can't guarantee that these solutions are good enough to solve your problem, but I would suggest at least trying:
1). Chromating the material; copper and brass will accept chromate.
2). Benzotriazole. I'm not a chemist, so someone may be able to explain better, but this material helps clean copper and keep it tarnish free.
Ted Mooney, P.E.
Pine Beach, New Jersey
Benzotriazole vs. Nickel Plating Protection for Conductive CopperApril 9, 2018
Q. I am looking to protect a copper welding lead clamp from oxidation to maintain a high conductivity and am wondering whether a nickel plating finish or if using benzotriazole as passivization would be allow for greater contact conductivity while offering adequate protection from oxidation. If it matters, we are looking to apply 800 amps through the lead clamp and the clamp can apply over 5,000 psi of clamp pressure.
Thank you all in advance for your help! My background is in structural engineering.
Product Designer - Charlottesville, Virginia
A. Hi Emmet. Basically, benzotriazole is a temporary corrosion inhibitor for copper, whereas nickel plating is a permanent one. I am not a contact designer either, but nickel plating works fine for contacts down to 1-1/2 V, and you'll see it on virtually all charging blocks, headphone jacks, HDMI cables, dry cell battery contacts, and low voltage signals of every sort (except for digital signals where precious metals must be used so there is absolutely no tarnish and resistance).
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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