PyroGenesis eliminates tungsten contamination in metal additive powders

PyroGenesis, a manufacturer of spherical metal powders using patented plasma processes, has announced that its additive manufacturing materials are officially free-from tungsten.

Known as “the Devil particle,” tungsten is a contaminant of metal powders, causing imperfections and concurrent weakness in a 3D printed part. Tungsten contamination has caused catastrophic part failures in the past, and is a major concern for the aerospace industry.

“This is a significant development in powder production,” comments P. Peter Pascali, CEO & President of PyroGenesis, “What is noteworthy is that within a few short months of having been made aware of this problem, by significant players in the industry, PyroGenesis was able to find an answer.”

Inside the crucible of PyroGenesis' plasma atomization process for metal powders. Photo via PyroGenesis on Twitter
Inside the crucible of PyroGenesis’ PUREVAPTM patent pending plasma process for making silicon from quartz. Photo via PyroGenesis

Nature of “the Devil Particle”

Tungsten has the highest melting point of all discovered elements and, as Pierre Carabin, Chief Technology Officer of PyroGenesis, explains, “Since the melting point of tungsten is higher than that of titanium, it does not melt during the AM printing process.”

The result, then, is a cluster of solid tungsten particles within an otherwise conformal 3D printed titanium part.

“Tungsten inclusions,” adds Carbin, “can become preferred sites for crack initiation. This has led to catastrophic failures and is clearly unacceptable, particularly in the aerospace industry.”

The source of contamination

Also the heaviest known element, tungsten has exceptional hardness and high density, making it a valuable ingredient in alloys used to make military armaments. It is used to make filament in light bulbs, the nib of ballpoint pens, rocket nozzles and more.

The heavy-metal’s versatile application is also the reason why it can be found contaminating metal powders that would otherwise be free of its presence.

Plasma nozzles used in the powder synthesis process often contain traces of the element. Therefore, PyroGenesis’ solution was to rid their nozzles of tungsten.

Diagram of the plasma atomization process (PAP) used to make spherical metal powders. Image via PyroGenesis
Diagram of the plasma atomization process (PAP) used to make spherical metal powders. Image via PyroGenesis

PyroGenesis’s plasma answer

Pascali explains, “We know of no other plasma atomization process (using DC torches) which uses tungsten free nozzles,”

“Plasma torches with tungsten nozzles are at high risk of having tungsten inclusions in their powders. We no longer have that risk.”

Additionally, all titanium powders produced by the company are screened for tungsten content, ensuring the quality of the material for its customers.

“This not only underscores PyroGenesis’ ability to quickly find solutions to complex issues,” adds Pascali, “but how these solutions can lead to economically valuable alternatives, and open the door to addressing this need with potential clients.”

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Featured image shows a metal alloy powder. Photo via PyroGenesis