Sawatzki, Simon ; Kübel, Christian ; Ener, Semih ; Gutfleisch, Oliver (2016)
Grain boundary diffusion in nanocrystalline Nd-Fe-B permanent magnets with low-melting eutectics.
In: Acta Materialia, 115
doi: 10.1016/j.actamat.2016.05.048
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
In order to combine the good thermal stability of nanocrystalline Nd-Fe-B magnets with the efficient grain boundary diffusion process (GBDP), low-melting eutectics have been mixed with Nd-Fe-B melt-spun ribbons, hot-compacted and subsequently die-upset. Transmission electron microscopy (TEM) analysis revealed the formation of 5–10 nm thick Dy-shells and a crystallography dependent diffusion into the individual solid grains on the nanoscale. Subsequent annealing at 600 °C leads to an enhanced diffusion but also some undesired Nd-O phases and induced grain growth depending on the annealing time, degree of deformation, strain rate and position within the sample. An optimized distribution of the low-melting eutectic was realized by milling the precursor powder and by using ternary alloys with reduced melting points. As a consequence a much higher effective increase in coercivity per wt%Dy was obtained compared to a homogeneous Dy-distribution which demonstrates the validity of this new approach.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2016 |
| Autor(en): | Sawatzki, Simon ; Kübel, Christian ; Ener, Semih ; Gutfleisch, Oliver |
| Art des Eintrags: | Bibliographie |
| Titel: | Grain boundary diffusion in nanocrystalline Nd-Fe-B permanent magnets with low-melting eutectics |
| Sprache: | Englisch |
| Publikationsjahr: | 15 August 2016 |
| Verlag: | Elsevier Science Publiching |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Acta Materialia |
| Jahrgang/Volume einer Zeitschrift: | 115 |
| DOI: | 10.1016/j.actamat.2016.05.048 |
| Kurzbeschreibung (Abstract): | In order to combine the good thermal stability of nanocrystalline Nd-Fe-B magnets with the efficient grain boundary diffusion process (GBDP), low-melting eutectics have been mixed with Nd-Fe-B melt-spun ribbons, hot-compacted and subsequently die-upset. Transmission electron microscopy (TEM) analysis revealed the formation of 5–10 nm thick Dy-shells and a crystallography dependent diffusion into the individual solid grains on the nanoscale. Subsequent annealing at 600 °C leads to an enhanced diffusion but also some undesired Nd-O phases and induced grain growth depending on the annealing time, degree of deformation, strain rate and position within the sample. An optimized distribution of the low-melting eutectic was realized by milling the precursor powder and by using ternary alloys with reduced melting points. As a consequence a much higher effective increase in coercivity per wt%Dy was obtained compared to a homogeneous Dy-distribution which demonstrates the validity of this new approach. |
| Freie Schlagworte: | Permanent magnet, Nd-Fe-B, Hot-deformation, Grain boundary diffusion process (GBDP), Low melting eutectic |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Funktionale Materialien 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften |
| Hinterlegungsdatum: | 08 Jul 2016 11:25 |
| Letzte Änderung: | 08 Jul 2016 11:25 |
| PPN: | |
| Sponsoren: | We thank Oliver Diehl for melt-spinning, Arne Grünewald for ONH analysis (both Fraunhofer IWKS) and the BMWi (Bundesministerium f. Wirtschaft und Technologie) via IGF (Industrielle Gemeinschaftsforschung), AiF (Allianz Industrie Forschung),, FVA (Forschungsvereinigung Antriebstechnik e.V.) FVA-Nr. 631 and the German federal state of Hessen through its excellence program LOEWE ″RESPONSE″ for financial support. |
| Export: | |
| Suche nach Titel in: | TUfind oder in Google |
 |
Frage zum Eintrag |
Optionen (nur für Redakteure)
 |
Redaktionelle Details anzeigen |
Drucken
Impressum