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Re: [TCML] keeping primary copper tubing nice and shiny



G Hunter wrote:
Gary, you are correct.  Pure silver is a much better conductor than silver oxide according to this ham radio site:

http://hamwaves.com/antennas/coils.html

Quote:

"At a temperature of 20°C (293.15K), silver (Ag) has a resistivity of 1.58·10-8Ωm, which is the lowest of all metals, and a temperature coefficient of 0.0038K-1. Silver[I] oxide (Ag2O) at this temperature has a 500 times higher resistivity of 8·10-6Ωm and a temperature coefficient of 0.004620K-1 [3]. Nonetheless it is still considered to be a conductor, whereas both copper[I] oxide (Cu2O) and copper[II] oxide (CuO) are semiconductors at room temperature."

Close quote.

Nuf said,

Greg



Even better, that page cited a source for the Ag2O resistivity (the paper by Chatterjee) which I'll have to look up at work.

But, also, bear in mind that at TC frequencies, the skin depth is so large compared to plating thickness that it's not like a HF loading coil. And even in a HF coil, the value of silver plating is dubious, at least from a loss standpoint. Low resistivity connections is a better reason (e.g. Silver oxide is a whole lot better than Copper oxide).

Also, what's the resistivity of silver sulfide (the usual tarnish)??

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