FAQ about Powder Synthesis and Development

Gas atomization is a method used to produce metal powders. A molten stream of metal is injected into a jet of high velocity gas, which breaks the molten stream into fine droplets. The droplets solidify and are collected for use in thermal spray processes, metal injection molding, and 3D printing/additive manufacturing. The type of gas atomization used at our facility is called “close-coupled discrete jet” gas atomization.

We have two atomizers, an experimental scale and a pilot scale. The table below shows their typical charge (or initial melt mass) capacities.

The input material form, such as pellets, shot, rods, bars, pig-ingots, crushed ingot, etc., will have a significant effect on the amount of material that can be loaded into the crucible.

The charge mass will not result in an equal amount of powder in your desired size range, and is discussed in the powder size distribution question below.

It's all in how you slice the bread.

When metal powders are produced, the size of the individual powder particles vary typically with a lognormal distribution. The powder size distribution (PSD) graphed below uses data from one of our aluminum alloy atomizations.

The median powder size, or D50, is near 48 µm. If the usable powder size range that is suitable for your work ranged from 20µm to 115µm, as represented by the boxes labeled A, B, and C, then this is an excellent distribution.

If you only want powders with diameters from 35um to 65µm, as represented by the box labeled B, this still an excellent distribution, as it is centered on the desired range; however, the total mass of that cut of powder will be only a fraction of the total mass of powder in the distribution.

If the powder you wanted was only the A cut or the C cut, then this distribution is not optimized to your specification and the major share of the powder is not usable for your intended purpose.

Since the alloy-- or loaf of bread-- is custom, it is made just for you and therefore you have to pay for the entire loaf. If you only want one slice of bread, box B right in the middle of the loaf, you still have to pay for the entire loaf.

This issue also affects commercial producers. They either have to find buyers who can utilize the whole loaf, or multiple buyers who each want a particular slice or slices from the loaf. Otherwise the unused portions are waste, or recycled if possible.

Pre-alloying is another factor that can affect the cost. If pre-alloying is required, to avoid issues like exothermic reactions or lowering the melting point of some high melting constituents, the costs will be higher in proportion to the amount of effort pre-alloying requires.

Lastly, the quality and/or scarcity of your ingredients also directly affects the cost. 

We can tune our die and melt system configuration to optimize toward a specified D50, or median powder size. Typical D50’s range from 15µm to 75µm. Larger or smaller targets can be archived. Once again, the powder will have a distribution of sizes around the median value. The powder can be “classified” into size fractions or cuts to any standard sieve ranges you desire. The table below shows standard sieve sizes. The distribution will be affected by the fluid properties of alloy - for example, highly viscous melts can produce needles instead of spherical particles.

No guarantees can be made. However for alloy systems of known character, we can confidently predict the likelihood of producing spherical powder. For systems that have never been atomized before, analogs may provide guidance about the potential morphology outcomes. It’s research -- you may just have to wait and see the end results.

We are required to use the U.S. Department of Energy contracting process, which uses agreements such a CRADAs (Cooperative Research and Development Agreement) or a simpler Strategic Partnership Project (or SPP), to fulfill the work. A statement of work, budget, and time-line or period of performance will be developed between the Lab and client. This pre-proposal will be submitted to the Lab administration. The Lab administration will then negotiate the actual contract terms with the client. The time required to generate, approve, and fund the final contract may be 4-6 weeks. Only then, and with the approval of the DOE, will the research work begin. To submit an inquiry to the PSDF for powder production or assessment please fill out this online form.(link to form)

Our main goal is facilitating research on powder metals for their application in the real world. The DOE restricts our efforts to producing powders that are not available from commercial suppliers. Further, the DOE does not want us to produce powder for direct resale; however, if value is being added to the powder then it may be acceptable. The PSDF is not intended to provide powder for original equipment manufacturing (OEM) operations on a regularly scheduled basis. Foreign entities can utilize the PSDF, but the DOE will require vetting of the work for export control, International Traffic in Arms Regulations (ITAR), and other concerns prior to approving such work.

Yes. We encourage observation visits and tours. Hosting visitors who are not U.S. citizens will require a pre-visit vetting process to gain DOE approval for the visit. This process may take 3-5 days, and must be completed prior to the visit. If a visitor’s country of origin is a U.S. Department of State designated “sensitive country,” the process will require more time for completion.

All gas atomized powders are subject to export license under the U.S. Dept. of Commerce, Export Administration Regulations, Export Control Classification Number (ECCN) 1C002.c.2.b.