Re: tungsten carbide properties

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

Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Terry, all,

One thing is sure you need to keep your gap cool, first for good
quenching, secondly if you have a piece of tungsten braze to
copper, just remember that the thermal expansion factor is
4.5*10^-6 K^-1 for tungsten and 16.5^-6 K^-1 for copper, almost 4
time for copper, that mean that each time they heat and cool, the
stress in the solder interface try to separate them. The thermal
EF for carbit is between 4.9 and 7.2*10^-6 K^-1

Cheers,

Luc Benard

Tesla list wrote:
> 
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> 
> Hi all,
> 
> A nice table of properties for tungsten carbide is at:
> 
> http://www.tungsten-carbide-dot-com/carbide.htm
> 
> It is not magnetic, apparently, so the skin depth may be reasonable.  It is
> only 9% as electrically conductive as copper so short fat electrodes are
> preferred.  Perhaps water cooled copper rods (pipes) with a tungsten
> carbide face brazed on would be nice.
> 
> I wonder if any disks of the material are commonly available that would be
> good for brazing onto copper pipe caps?  (I assume copper can be brazed
> without just melting down...) I'll have to pull out the giant MSC
> catalog...  Cutting or machining the stuff is probably far from
> desirable...  I tried lead/tin soldering and that does not work.  Tungsten
> faces for this prototype gap is what I am looking for:
> 
> http://hot-streamer-dot-com/temp/ProtoSTSG.jpg
> 
> That gap can be filled with water to control the temperature and has nice
> faces for field distortion triggered gap things...
> 
> I wonder if copper sulfate and electricity could plate them with copper so
> they could be easily soldered.  With water cooling, the solder would not
> melt.  Maybe Mike H. knows :-)
> 
> Such electrodes may simply never wear out or need maintenance.  Ted had to
> clean is haunted house gaps every two hours last year so trying to help him
> out...
> 
> Surprisingly, it is fairly thermally conductive at around 85 W/m-k.  Silver
> is 415 and copper is 389.
> 
> Cheers,
> 
>         Terry