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Electrical and magnetic properties of hot-deformed Nd-Fe-B magnets with different DyF3 additions

Sawatzki, Simon and Dirba, Imants and Schultz, Ludwig and Gutfleisch, Oliver (2013):
Electrical and magnetic properties of hot-deformed Nd-Fe-B magnets with different DyF3 additions.
In: Journal of Applied Physics, AIP Publishing LLC, p. 133902, 114, (13), ISSN 00218979,
[Online-Edition: http://dx.doi.org/10.1063/1.4822026],
[Article]

Abstract

The effect of deformation and DyF3 additions on the electrical resistivity and the magnetic performance has been studied in hot-deformed Nd-Fe-B melt-spun ribbons and correlated with respective microstructures. Despite the nanocrystallinity of hot-compacted magnets, the specific electrical resistivity measured by four-point-method was shown to be comparable with that of sintered magnets. Die-upsetting reduces electrical resistivity within the magnetically hard plane because of an enhanced shape anisotropy of the grains. The addition of DyF3 overcompensates this reduction due to the presence of electrically insulating Dy-F rich inclusions and thus reduces eddy current losses within the magnet. Magnetic measurements reveal an increase in coercivity without a change in remanence for die-upset magnets with a total height reduction of 63% and 1.2 wt. % Dy (1.6 wt. %DyF3). Both properties, remanence and coercivity, demonstrate an effective reduction in heavy rare earth Dy for Nd-Fe-B magnets.

Item Type: Article
Erschienen: 2013
Creators: Sawatzki, Simon and Dirba, Imants and Schultz, Ludwig and Gutfleisch, Oliver
Title: Electrical and magnetic properties of hot-deformed Nd-Fe-B magnets with different DyF3 additions
Language: English
Abstract:

The effect of deformation and DyF3 additions on the electrical resistivity and the magnetic performance has been studied in hot-deformed Nd-Fe-B melt-spun ribbons and correlated with respective microstructures. Despite the nanocrystallinity of hot-compacted magnets, the specific electrical resistivity measured by four-point-method was shown to be comparable with that of sintered magnets. Die-upsetting reduces electrical resistivity within the magnetically hard plane because of an enhanced shape anisotropy of the grains. The addition of DyF3 overcompensates this reduction due to the presence of electrically insulating Dy-F rich inclusions and thus reduces eddy current losses within the magnet. Magnetic measurements reveal an increase in coercivity without a change in remanence for die-upset magnets with a total height reduction of 63% and 1.2 wt. % Dy (1.6 wt. %DyF3). Both properties, remanence and coercivity, demonstrate an effective reduction in heavy rare earth Dy for Nd-Fe-B magnets.

Journal or Publication Title: Journal of Applied Physics
Volume: 114
Number: 13
Publisher: AIP Publishing LLC
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Functional Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 10 Mar 2014 09:56
Official URL: http://dx.doi.org/10.1063/1.4822026
Identification Number: doi:10.1063/1.4822026
Funders: We thank the BMWi (Bundesministerium f. Wirtschaft und Technologie) via IGF (Industrielle Gemeinschaftsforschung), AiF (Allianz Industrie Forschung), and FVA (Forschungsvereinigung Antriebstechnik e.V.) , as well as the DBU (Deutsche Bundesstifung Umwelt) for financial support.
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