Critical Materials Institute Develops Less Expensive 3D Printed Magnets

3D printing is an eclectic technology, used for applications in almost every industry you can think of. It has come a long way from simply being able to make things out of plastic or pure metal, and has begun to be used to make materials with special properties such as conductivity and magnetism. Many researchers have developed different ways to 3D print magnets, and the latest organization to contribute to the field is the US Department of Energy’s Critical Materials Institute (CMI).

CMI used 3D laser metal printing to optimize a permanent magnet material that, the institute believes, could be a more economical alternative to the expensive rare earth neodymium iron boron (NdFeB) magnets used for some applications. The alloy used by CMI was composed of cerium, a less expensive and more plentiful rare earth, as well as cobalt, iron, and copper. The researchers 3D printed various samples demonstrating a range of compositions.

“This was a known magnet material, but we wanted to revisit it to see if we could find exceptional magnetic properties,” said CMI scientist Ryan Ott. “With four elements, there is a vast space of compositions to hunt around in. Using 3D printing greatly accelerates the search process.”

It can take weeks to produce magnets using conventional production methods, but 3D printing a range of them only took two hours. The researchers identified the samples with the most promising properties, then made a second set of samples using conventional casting methods and compared them to the originals. These confirmed the findings of the 3D printed samples.

“It is very challenging to use laser printing to identify potential permanent magnet phases for bulk materials because of the need to develop the necessary microstructure,” said CMI scientist Ikenna Nlebedim. “But this research shows that additive manufacturing can be used as an effective tool for rapidly and economically identifying promising permanent magnet alloys.”

The research was documented in a paper entitled “Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications,” which you can access here. Authors include F. Meng, R.P. Chaudhary, K. Ganhda, I.C. Nlebedim, A. Palasyuk, E. Simsek, M.J. Kramer, and R.T. Ott.

“Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser,” the paper explains. “Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5–20 at.%) and Co (60–45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)₅ microstructure in which high coercivity (H_c > 10 kOe) can be achieved without any microstructural refinement.”

The Critical Materials Institute is a Department of Energy Innovation Hub led by the DOE’s Ames Laboratory and supported by the Office of Energy Efficiency and Renewable Energy’s Advanced Manufacturing Office. CMI researches ways to reduce or eliminate reliance on rare earth metals and other materials currently critical to clean energy.

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