Fabrication of highly dense isotropic Nd-Fe-B nylon bonded magnets via extrusion-based additive manufacturing

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Li, Ling
Jones, Kodey
Sales, Brian
Pries, Jason
Nlebedim, I. C.
Jin, Ke
Bei, Hongbin
Post, Brian
Kesler, Michael
Rios, Orlando
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Lograsso, Thomas
Ames Laboratory Division Director
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Ames National Laboratory

Ames National Laboratory is a government-owned, contractor-operated national laboratory of the U.S. Department of Energy (DOE), operated by and located on the campus of Iowa State University in Ames, Iowa.

For more than 70 years, the Ames National Laboratory has successfully partnered with Iowa State University, and is unique among the 17 DOE laboratories in that it is physically located on the campus of a major research university. Many of the scientists and administrators at the Laboratory also hold faculty positions at the University and the Laboratory has access to both undergraduate and graduate student talent.

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Materials Science and Engineering

The Department of Materials Science and Engineering teaches the composition, microstructure, and processing of materials as well as their properties, uses, and performance. These fields of research utilize technologies in metals, ceramics, polymers, composites, and electronic materials.

The Department of Materials Science and Engineering was formed in 1975 from the merger of the Department of Ceramics Engineering and the Department of Metallurgical Engineering.

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Magnetically isotropic bonded magnets with a high loading fraction of 70 vol.% Nd-Fe-B are fabricated via an extrusion-based additive manufacturing, or 3D printing system that enables rapid production of large parts. The density of the printed magnet is ∼ 5.2 g/cm3. The room temperature magnetic properties are: intrinsic coercivity Hci  = 8.9 kOe (708.2 kA/m), remanence Br  = 5.8 kG (0.58 T), and energy product (BH)max = 7.3 MGOe (58.1 kJ/m3). The as-printed magnets are then coated with two types of polymers, both of which improve the thermal stability as revealed by flux aging loss measurements. Tensile tests performed at 25 °C and 100 °C show that the ultimate tensile stress (UTS) increases with increasing loading fraction of the magnet powder, and decreases with increasing temperature. AC magnetic susceptibility and resistivity measurements show that the 3D printed Nd-Fe-B bonded magnets exhibit extremely low eddy current loss and high resistivity. Finally, we demonstrate the performance of the 3D printed magnets in a DC motor configuration via back electromotive force measurements.


This is a manuscript of an article published as Li, Ling, Kodey Jones, Brian Sales, Jason L. Pries, I. C. Nlebedim, Ke Jin, Hongbin Bei, Brian K. Post, Michael S. Kesler, Orlando Rios, Vlastimil Kunc, Robert Fredette, John Ormerod, Aaron Williams, Thomas A. Lograsso, and M. Parans Paranthaman. "Fabrication of highly dense isotropic Nd-Fe-B nylon bonded magnets via extrusion-based additive manufacturing." Additive Manufacturing 21 (2018): 495-500. DOI: 10.1016/j.addma.2018.04.001. Posted with permission.

Mon Jan 01 00:00:00 UTC 2018