Here we explore iron pickup risk in titanium powder. Part 2 in this series examined contamination risk at the top of the atomization process when the electrode of titanium or other pre-alloyed material is heated in the crucible to reach the molten state. (Read Quality Assurance for Gas-Atomized Powders.)
We follow the titanium further into the atomizer on its journey to becoming spherical powder for use in producing 3D-printed parts. As the electrode melts in the crucible molten metal droplets fall into the atomizer tower. The droplets cool in-flight and form spherical powder. Gravity pulls the powder into the atomizer.
As it impinges the sides of the tower and piping, which are typically made of steel, the hot powder may strip off small amounts of steel from the atomizer. This introduces an iron pickup risk.
In the paper, "Influence of Foreign Particles on Fatigue Behavior of Ti 6Al-4V Prealloyed Powder Compounds," S.W. Schwenker, D. Eylon and F.H. Froes demonstrated the detrimental effects of iron pickup on the end component's properties.
The severity of iron pickup to finished parts' performance led or team of metallurgists to research ways to minimize this contamination risk. The result is a patent-pending atomizer, constructed with an all-titanium tower, cone, piping, cyclone, and collection container. This design eliminates any risk of iron pickup during atomization.
Be sure to inquire about iron pickup risk as you engage suppliers.