6K’s Refractory Metal 3D Printing Powders Enable Space Applications

6K Additive has announced the commercial scale production of refractory metal powders for 3D printing. Refractory metals are a group of metals on the periodic table with the distinct quality of an absurdly high melting point, making them difficult to manufacture but very useful for high-heat, high-pressure applications in space, aerospace, medicine, and defense. Turning these metals into powder is done through 6K’s proprietary production scale microwave plasma system, the UniMelt. Quadrus Corporation was able to use 6K’s refractory metal powder in the production of throat inserts for rocket motors.

6K itself is a leader in sustainably producing advanced materials for energy storage and additive manufacturing. At the heart of the company is the UniMelt, the only commercial grade plasma production system in the industry. The UniMelt is able to produce materials for both energy storage and additive manufacturing in a fraction of the time and with little to no waste compared to conventional manufacturing processes. Just earlier this year the UniMelt platform won the Top Product of the Year Award in Environment + Energy Leadership.

6K’s UniMelt microwave plasma recycles feedstock into AM-ready metal powder. Image courtesy of 6K.

The UniMelt process uses the fourth phase of matter, plasma, to create a uniform high temperature production zone of four inches in diameter and eight feet long, the machine in its entirety measures 20 feet by 20 feet and can produce 100 tons of material per year. By combining multiple processes into one this sort of manufacturing cuts time by a few days to a few seconds compared to conventional manufacturing and is able to use scrap metal as feedstock. The system reaches an internal temperature of 6000° Kelvin, the temperature of the surface of the sun, hence the name 6K.

The company announced it is now able to use their UniMelt system to manufacture refractory metals such as tungsten, rhenium, and niobutin. Refractory metals have melting points greater than 3,632°F and always have three, four, or five electrons in their shells, forming strong covalent bonds with neighboring atoms. This results in high melting points compared to the other metals, such as titanium or nickel. Tungsten has the highest melting point out of all metals at 6,192°F.

Frank Roberts, 6K Additive President said “The leading defense organizations are not only looking for refractory materials like tungsten and rhenium, they are looking for it at production scale. The uniqueness of 6K’s UniMelt ® microwave plasma process, combined with the expertise of our operations team, has allowed us to manufacture production scale volumes for many of the refractory powders like tungsten and tungsten/rhenium. We have spheroidized the full spectrum of refractory powders including tantalum, niobium and molybdenum and we are ready to help organizations advance their applications with these materials.”

Alabama-based company Quadrus Corporation is using 6K’s tungsten-rhenium metal powder to 3D print a non-eroding throat insert for a solid rocket motor nozzle. In the past, the company 3D printed innovative solutions for NASA, being a part of the disruption 3D printing has had on space travel and habitation.

A 3D printed, non-eroding throat insert for a solid rocket motor nozzle, made by Quadrus Corporation using 6K’s tungsten-rhenium powder. Image courtesy of 6K.

“We have a focus on propulsion applications that require high-temperature, high-strength materials used in modern rocket nozzle applications. Our tungsten/rhenium powder spheroidized by 6K processed exceptionally well in our selective laser melting machines,” explained Joe Sims, Director of the Quadrus Advanced Manufacturing Division. “Having a reliable, trusted supply chain partner like 6K Additive for refractory materials is critical to our business and to our defense customers. Our powder quality requirements are extremely high and 6K Additive easily cleared that hurdle for us.”

6K has had a busy last few years, developing new technologies, manufacturing techniques, new partnerships, clients, and many rounds of funding. Its proprietary UniMelt system is backed by 18 patents and is the only one like it in the industry. It will be exciting to see the partnerships and clients refractory metals will bring to 6K.