ATI Wah Chang produces powders from zirconium,
hafnium, niobium, and vanadium through the
hydride-dehydride process. The metals, in various
purities or alloys, are reacted to form brittle
hydrides. The hydrides are crushed and classified
to desired particle size ranges. For dehydride
powders, the hydride is out gassed under vacuum
yielding the original metal or alloy as a powder.
ATI Wah Chang has the capability for processing powder under
inert gas through all operations to maintain
material purity.
Hydride and/or dehydride powder from these metals
is angular and irregular in shape. The particle
aspect ratio averages 2.5:1 with the distribution
trailing off at approximately 5:1. The surface is
of an angular density for vacuum sintering and
subsequent processing. he crushing process
produces a full distribution or spectrum of
particle sizes. This particle size distribution
can be controlled to some degree via
classification methods by removing upper and/or
lower limits. However, as the fine and coarse
limits come closer together the yield diminishes
and the process cost increases. Powers are
currently offered down to a -325 (44m
m) distribution.
For any given particle size range a tolerance must
be agreed upon in terms of the percentage of
over/undersize acceptable. Sharp cut offs of the
particle size distribution are not practical,
however the distribution mean may be shifted in
one direction or another. Differences between
sieves of the same size will yield slightly
different results as well
All of the powder products provided can sustain
combustion but special care should be exercised
with -200 and down mesh zirconium and hafnium
powders (and hydrides) to avoid
spontaneous pyrophoric reaction.
