Nd-Fe-B sintered magnets fabrication by using atomized powders

R. Goto, S. Sugimoto, M. Matsuura, N. Tezuka, Y. Une, M. Sagawa

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Nd-Fe-B sintered magnets are required to achieve high coercivity for improvement of their thermal stability. Dy is added to increase coercivity, however, this element decrease magnetization and energy products. Therefore, Dy-lean Nd-Fe-B sintered magnets with high coercivity are strongly demanded. To increase coercivity, it is necessary that microstructure of sintered magnets is consisted of both fine main phase particles and homogeneously distributed Nd-rich phases around the main phase. To meet those requirements, Nd-Fe-B atomized powders were applied to the fabrication process of sintered magnets. Comparing with the case of using strip casting (SC) alloys, jet-milled powders from atomized powders show homogeneous distribution of Nd-rich phase. After optimized thermal treatment, coercivities of sintered magnets from atomized powders and SC alloys reach 1050 kAm-1 and 1220 kAm-1, respectively. This difference in coercivity was due to initial oxygen concentration of starting materials. Consequently, Nd-rich phases became oxides with high melting points, and did not melt and spread during sintering and annealing.

Original languageEnglish
Article number012029
JournalJournal of Physics: Conference Series
Volume266
Issue number1
DOIs
Publication statusPublished - 2011

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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