Re: Electrical Properties of Brass

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Ken,

At 09:50 AM 4/20/2003 -0700, you wrote:
>Terry, I've always wondered about this reasoning.  Since the oxide layer
>has high resistance, would not there be low RF current level in it?
>Would that current, then, not have a much-reduced effect in establishing
>the RF current path?  And would not the main RF current, then, seek a
>path somewhat below the oxide layer, thus entering the region of
>relatively lower resistance within the pure aluminum?
>
>Ken Herrick
...

We have RF effects forcing the current to the outside and resistive effects 
forcing current in....  Exactly where the current goes and what the loss 
is, is an interesting problem I am sure ;-))  In a few days I am getting 
some high power RF coils that are aluminum heavy plated with silver.  They 
work well since the currents travel in the thin silver layer.  What will be 
fun to see is what happens if the plating gets a crack.  We "think" it will 
incinerate.  But have to see for sure.  Stay tuned...

I or Gary Lau may be able to get two coils that are exactly the same 
dimension but one is copper and the other aluminum and test the resistance 
on a fancy HP machine.  Soaking or boiling the aluminum one in salt water 
will certainly oxidize it well.  I'll ask the guys that know how to run the 
HP network analyzer beast to see if that is "easy" to do.

Cheers,

         Terry