Page 14 - Bullion World issue 2 June 2021

Bullion World | Issue 02 | June 2021

The revolution

of atomized PM

powder

Mr Eng. Roberto Guidali
CEO, Italimpianti Orafi S.p.a

Atomizing creates fine-
grade precious metal (PM)
powders which have made a
compelling impact on world
markets. It liberalizes alloy
composition for PM refining
and produces powders
for many distinct industrial
applications. PM powders
have triggered the creation
of heretofore unimagined
products, and new industries
have been forged with
slashed costs and bolstered particles-of-powder-formed- particles-of-powder-formed-
profits. with-gas-atomization with-water-atomization

POWDER METALLURGY - THE
BREAKTHROUGH WE'VE BEEN LOOKING FOR

Water and Gas atomization (WA and we can directly refine gold alloys with up
GA respectively) have broadened the to 20% silver. For GA-formed powders,
range of PM products, advancing from the vast quantity of their industrial
'standard' ingots, bars, medals, etc. to applications has led to a stable demand
atomized powders. for those PMs.

The value of PM ingots (and their The use of atomizing technologies
jewelry) depends on the world market permits the synthesis of a variety of
far that PM, and on the fluctuations in alloys. It is now possible to fabricate
the demand for them. As the capacity components that otherwise would
to form new alloys and chemical decompose or disintegrate. All
compounds from a PM powder develops, considerations of solid-liquid phase
then in tandem, the PM takes on an changes can be ignored, so powder
elevated and stable value. processes are more flexible than casting, gas-atomizer-melting-detail
extrusion or forging techniques. For
The production of PM powders by example, we can now have a controlled
WA permits the broadening of the and uniform porosity of solids.
composition of raw gold alloy to Water technology is mainly used for sintering
be refined directly by wet chemical The main applications for atomized or HIP, as the dendritic form tends to cling
processes, i.e., by one process rather powder are HIP (Hot Isostatic Pressing), more. While gas atomization allows greater
than by two, making it faster, and saving Additive Layer Manufacturing (3D smoothness of the powders in the deposition
energy, chemicals, and manpower. Now printing) or sintering. But these are only phase of the layers in 3D printing, given the
examples. sphericity of the grains.
14