[Amps] Silver Plating Tank Coil ??

[Bill Fuqua]

  Gold plating is often done over nickel. Apparently the copper atoms tend 
to diffuse thru the
thin gold layer. To stop this a plating of much less porous nickel is used 
as an interface
layer between the copper and gold. I don't recall how thick the nickel is 
but it is much thicker than
the gold layer. It may still be thin enough not to affect the RF resistance 
of the coil but I just don't know
without investigating it further.
   I can say that I have seen lots of gold plated cavities and RF 
components in mostly military applications.

73
Bill wa4lav

At 04:42 AM 9/20/2009 -0400, ToddRoberts2001 at aol.com wrote:


>Hi  All,
>Thanks for the comments on Gold  plating a tank coil.
>I think one thing that was overlooked is Gold plating is  usually extremely
>thin, on the order of 1 or 2 microns, or 0.04 to 0.08  mil.
>At HF frequencies the skin effect depth is orders of  magnitude
>greater than this, perhaps 2 to 4 mils, so the RF current stays 99%  in the
>more
>conductive copper underneath the gold plating. The Gold plating  does indeed
>protect the surface from tarnish, and would have an  almost
>negligible effect on the RF resistance of the tank coil at HF
>frequencies.
>
>73 - Todd WD4NGG
>
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