Hi Hilary,

Sounds reasonable what you say.
Molybdenum, indeed, could ba a candidate. I thought about it but was not
certain it would oxize tpp easily... so I did not mention it.

If using Ni, what about using small Mo cups instead of Sn or Ag (Ag might be
OK too). Then there is no risk of alloy formation or eutectic with Mo.

Another metal with high melting point is tungsten. But I have the strong
feeling (I have no handbooks at hand to look this up) it might oxidize too.
And, after being heated to relatively high temperatures W becomes very
brittle (rearangement in structure due to heating?), giving problems if
needed to be reloaded or cleaned after a while.

Best wishes,
Pier.


> I think that titanium will tie up all the oxygen and fall apart (TiO2).  It
> would be good for a short time for hydrogen ... see below.
>
> I tried tantalum sheet and it was marvellous for producing absolutely no CO
> until it was used up!  Then it fell apart ...  I have some niobium sheet
> which I have not yet tried as I now expect it to go the same way.
>
> It has been suggested to me that molybdenum might be possible, and its
> oxide and melting properties LOOK good.
>
> My experience of Ni sheet rolled into a tube is that we are using it close
> to its melting point (1455 degrees) at 1060 degrees .  It rapidly
> 'dissolves' away.  Perhaps as an alloy or eutectic with the tin from the
> cups.  If you weren't using tin it might be OK.  I haven't tried nickel
> above 1150 degrees as I am a pessimist!
>
> Hil
>
> .
>
> Hilary Le Q. Stuart-Williams PhD.
> Research Officer in Stable Isotopes
> Environmental Biology Group
> Research School of Biological Sciences
> Australian National University
> Canberra, ACT, Australia
> (02) 6125 2099
> Personal home: www.webone.com.au/~hnksw
>
>