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Which coating has best conductivity?

Hi all,

First, I'd like to say that having this website is a great asset to the finishing community. Looking through here for the last two days has given me a lots of new info. I currently am looking at multiple coatings used in an electrical application and have noticed that I need a more conductive finish. I have used both galvannealed and pre-galvanized materials and have noticed that the conductivity is not as great as when compared to a electro-zinc plating. Unfortunately, I can't use a zinc plating due to zinc whiskers? Are there any other coatings I can use (cost sensitive) that will give me a better results than galvannealed or pre-galvanized? Thanks,

Stan Brzezniak
Product Engineer - Chicago, Illinois, USA
2007

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Thanks for the kind words, Stan. Alloy zinc platings like zinc-nickel and tin-zinc can offer good conductivity, sacrificial protection, and a lower propensity for whiskering (because they are alloys). But the "standard" non-precious plating for low contact resistance is electroless nickel.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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2007

Hi all,

Thanks for answering my last post about what coating was best for conductivity. Since then, I have chosen to go with pre-galvanized steel and initially it has worked great as the net resistance across my joint has had no problems meeting the requirements. I now have come up with a new issue that seems like the conductivity gets worse if I reuse the parts over and over(right now they have been installed and reinstalled about 12-15X). the conductivity has worsened and now I am no longer passing the requirements. My question is whether this is normal or not for pre-galvanized material? Most likely these parts will be installed and not removed for an extended period of time, but I do have a concern about my results not staying the same after a few uses. As always, any help would be appreciated.

Stan

Stan Brzezniak
Engineer - Chicagoland, Illinois, USA