[time-nuts] OCXO housings - Why copper and not iron/steel?

[Tobias Pluess]

Also an interesting material when high thermal conductivity is considered
is boron nitride. It is around  five times better than copper, comparable
to diamond and can be sintered to a ceramic material.
Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very
good electrical insulator.
A boron nitride OCXO would indeed be interesting! :-)

I use certain kinds of boron nitride at work to increase the the thermal
conductivity of some plastic materials.

Tobias


On Sat., 31 Oct. 2020, 03:57 Bruce Griffiths, <bruce.griffiths at xtra.co.nz>
wrote:

> Not true
> The Wiedemann-Franz gives the ratio of the thermal conductivity to
> electrical conductivity of a metal:
> ( pi^2 / 3 ) * ( (k/e)^2 ) * T
>
> Bruce
> > On 31 October 2020 at 12:49 "Dr. David Kirkby" <
> drkirkby at kirkbymicrowave.co.uk> wrote:
> >
> >
> > On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las at intercat.com.br>
> wrote:
> >
> > > My bad... copper is the second, losing only to silver, as a thermal
> > > conductor.
> > >
> >
> > I think you are mistaken.  Copper is second to silver for *electrical*
> > conductivity, but I doubt that is so for thermal conductivity. I think
> > diamond, which is a form of carbon, is the best thermal conductor, and
> > around 5x better than copper.
> >
> > Dave
> >
> > --
> > Dr. David Kirkby,
> > Kirkby Microwave Ltd,
> > drkirkby at kirkbymicrowave.co.uk
> > https://www.kirkbymicrowave.co.uk/
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> >
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