Effects of magnetic field annealing on the hard magnetic properties of milled Nd-Fe-B powders

Journal Article · 05 October 2023 · Journal of Magnetism and Magnetic Materials

DOI: https://doi.org/10.1016/j.jmmm.2023.171328 · OSTI ID:2305663

Parmar, Harshida ^[1]; Liu, Xubo  ^[1]; Gandha, Kinjal ^[1]; Paranthaman, M. Parans  ^[2]; Nlebedim, Ikenna C. ^[1]

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1. Ames Laboratory (AMES), Ames, IA (United States). Critical Materials Institute
2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

In this study, we report the effect of magnetic field annealing (MA) in relieving the stress induced during the milling of Nd-Fe-B sintered magnets. The effect of MA processing parameters and particle size on the magnetic properties were investigated. Based on the results, magnetic field annealing is more effective in improving the magnetic properties of larger size particles, compared to finer particles. Our computational study on the role of particle surface defects in bi-modal particle distribution agrees with results obtained experimentally. In conclusion, magnetic field annealed powder has been successfully used to develop 4.6 g.cm^-3 density bonded magnets with 75 vol% of magnetic powder and polyamide 12 (nylon 12) polymer binder resulting in 11.3 MGOe energy product.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Materials & Manufacturing Technologies Office (AMMTO); USDOE Office of Science (SC)
• Grant/Contract Number: AC02-07CH11358; C05-00OR22725; AC05-00OR22725
• OSTI ID: 2305663
• Alternate ID(s): OSTI ID: 2448144
• Report Number(s): IS-J-11,166
• Journal Information: Journal of Magnetism and Magnetic Materials, Vol. 587; ISSN 0304-8853
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English