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Rhenium platinum alloy


#1

According to TheBullionDesk.com of Nov. 8/07, Rhenium became the
7th. PGM. MetalPrices.com of July 10/08 predicted a rise from
then-$350/oz or so to perhaps $1,000. It has great heat resistance so
6% of the alloy in newer aircraft engines is Re. Has anyone worked
with it so as to comment on its reactivity? Since it is not found in
nature in elemental state, is it too reactive for jewelry use?


#2

Rhenium is an important part of nickel superalloys used in high
temperature turbine blades in aircraft engines. The alloys are cast
as single crystals and the purpose of the Re is to control the growth
of the crystal direction and prevent the dendritic growth from
changing the composition of the main alloy as it cools and
solidifies. Re is, on its own, poisonous and like its more toxic
brother osmium, oxidises more readily than Pt or Rh which is why it
is not used in jewellery. there was discusion about whether Rhodium
jewellery would be commercially viable as the Japanese were keen on
it at one point. Iridium and rutheniumis are cheapest of the Pt
group metals at only a few dollars an ounce but again not suitable
for jewellery. they are used in Pt and Pt/Au alloys for crucibles,
thermocouples and heating elements, the alloy is changed to give the
property you want-wetting or non-wetting, high or low change in
resistance at high temp etc. Palladium used to be as cheap as silver
until it was used in catalytic converters in cars and then it shot
up in price. If you can think of a use for all of the other Pt group
metals Johnson Matthey would love to hear from you.

nick


#3

Do you know of any practical application to the fact that at least
one Re compound can scratch diamond?


#4
Do you know of any practical application to the fact that at least
one Re compound can scratch diamond? 

I would like to see the documentation on this :>).

Mark Chapman


#5
I would like to see the documentation on this :). 

Google around on ReB2. It is a compound rather than an alloy.


#6

http://www.nsf.gov/mps/dmr/highlights/07highlights/ssmc/0453121_Kaner.ppt

(Power Point File)

For a paper on the “hardness” of Rhenium Diborane, and yes it will
scratch diamond…

Cheers, Thomas Janstrom.
Little Gems.
http://tjlittlegems.com


#7
For a paper on the "hardness" of Rhenium Diborane, and yes it will
scratch diamond..... 

First I’ll say this is all news to me - no expert. A better source
is, as usual, Wikipedia. The spelling is different than above for
some reason, but it’s the same stuff. Also links to the original
paper in Science. It only scratches diamond in one axis, not all
three. And I gather from the discussion that the “scratching of
diamond” part was given a bit of an edge with the pressure used and
stuff… Not important, it’s interesting…


#8
For a paper on the "hardness" of Rhenium Diborane, and yes it will
scratch diamond..... 

Whenever topic of scratching diamonds comes up, it is always grabs
my attention. There are a few problems with this discussion.

Rhenium diboride simply means rhenium and two atoms of Bohr, is salt
and not metal. Rhenium diboride relates to rhenium in the same way as
aluminum relates to sapphire. Sapphire can be called aluminum oxide.
If I want to be real fancy, I can even call it diAluminum triOxide,
which means two atoms of aluminum combined with three atoms of
oxygen.

Second thing is that scratching the diamond. I question it because
according to document, the test was done on diamond film and not on
crystal. In diamond films C-axis orientation coincides with film
Z-direction, or along film thickness. Running a point across a
diamond film make film very vulnerable to cleavage. That is exactly
why we do not use scratch test in gemological examinations anymore.
It
is a known fact that diamond can be damages by contact with softer
than diamond substances.

Until more reliable tests are done, I shall remain highly skeptical
of any claims of similar nature.

Leonid Surpin
www.studioarete.com