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Net-shape and crack-free production of Nd–Fe–B magnets by hot deformation

Dirba, I. and Sawatzki, S. and Gutfleisch, O. (2014):
Net-shape and crack-free production of Nd–Fe–B magnets by hot deformation.
In: Journal of Alloys and Compounds, Elsevier Science Publishing, pp. 301-306, 589, ISSN 09258388, [Online-Edition: http://dx.doi.org/10.1016/j.jallcom.2013.11.188],
[Article]

Abstract

In order to reduce the amount of material waste and therefore to use the precious rare earth element Nd in a more efficient way, routes for the production of crack-free hot-deformed nanocrystalline Nd–Fe–B magnets (using melt-spun ribbons as a precursor) have been investigated. In contrast to the conventional route in which material flows into a cavity, pressing tool has been used in order to exert a back pressure during backward extrusion, leading to crack-free and net-shape production of radially oriented ring magnets, without detrimental influence on magnetic properties. Micrographs demonstrate overall good alignment of elongated platelet shaped grains with radially oriented c-axis in most parts of the ring. A mean remanence Jr = 1.27 T and coercivity μ0iHc = 1.5 T has been obtained. Degree of texture reaches around 0.7. Furthermore, die-upsetting has been performed for different degrees of deformation to obtain crack-free, mechanically and magnetically homogenous, axially oriented tablet magnets.

Item Type: Article
Erschienen: 2014
Creators: Dirba, I. and Sawatzki, S. and Gutfleisch, O.
Title: Net-shape and crack-free production of Nd–Fe–B magnets by hot deformation
Language: English
Abstract:

In order to reduce the amount of material waste and therefore to use the precious rare earth element Nd in a more efficient way, routes for the production of crack-free hot-deformed nanocrystalline Nd–Fe–B magnets (using melt-spun ribbons as a precursor) have been investigated. In contrast to the conventional route in which material flows into a cavity, pressing tool has been used in order to exert a back pressure during backward extrusion, leading to crack-free and net-shape production of radially oriented ring magnets, without detrimental influence on magnetic properties. Micrographs demonstrate overall good alignment of elongated platelet shaped grains with radially oriented c-axis in most parts of the ring. A mean remanence Jr = 1.27 T and coercivity μ0iHc = 1.5 T has been obtained. Degree of texture reaches around 0.7. Furthermore, die-upsetting has been performed for different degrees of deformation to obtain crack-free, mechanically and magnetically homogenous, axially oriented tablet magnets.

Journal or Publication Title: Journal of Alloys and Compounds
Volume: 589
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Nd–Fe–B, Permanent magnet, Die-upsetting, Hot deformation, Backward extrusion
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: 13 Mar 2014 12:17
Official URL: http://dx.doi.org/10.1016/j.jallcom.2013.11.188
Identification Number: doi:10.1016/j.jallcom.2013.11.188
Funders: We thank the BMWi (Bundesministerium f. Wirtschaft und Technologie) via IGF (Industrielle Gemeinschaftsforschung), AiF (Allianz Industrie Forschung), FVA (Forschungsvereinigung Antriebstechnik e.V.), and the DBU (Deutsche Bundesstifung Umwelt) for financial support as well as Prof. L. Schultz (IFW Dresden) for hosting the DBU Programme.
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