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