Isotropic bulk exchange-spring magnets with 134 kJ/m3 prepared by spark plasma sintering method

Hideaki Ono, Norihisa Waki, Munekatsu Shimada, Tatsuo Sugiyama, Akira Fujiki, Hiroshi Yamamoto, Masato Tani

Research output: Contribution to journalConference articlepeer-review

38 Citations (Scopus)


Densification of exchange-spring magnet ribbons of NdxFe85-xCo8V1B6 (x = 7-11) alloys has been investigated. The starting ribbon powders containing amorphous parts were prepared by melt spinning and were compacted by using a Spark Plasma Sintering (SPS) method. SPS is a type of solid compression sintering similar to hot-pressing and the sintering promotion factor is self heat generation by electric discharges between particles when the on-off D.C. pulse is applied. The bulk magnets indicated the springback phenomenon, pointing to multiple phases of the Nd2Fe14B type and the α-Fe type, and had isotropic magnetic properties. With increasing Nd content, Br decreased from 1.05 T to 0.82 T and HcJ increased from 256 kA/m to 832 kA/m. These changes were equivalent to those of the starting ribbons following annealing. The grain sizes of these bulk magnets were about 40 nm when x = 7-11. Under optimum preparation conditions, bulk Nd10Fe75Co8V1B6 magnet indicated (BH)max = 134 kJ/m3 (16.8 MGOe).

Original languageEnglish
Pages (from-to)2552-2554
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number4 I
Publication statusPublished - 2001 Jul
Externally publishedYes
Event8th Joint Magnetism and Magnetic Materials -International Magnetic Conference- (MMM-Intermag) - San Antonio, TX, United States
Duration: 2001 Jan 72001 Jan 11


  • Bulk exchange-spring magnets
  • Densification of melt-spun ribbons
  • Isotropic magnetic properties
  • Nd-Fe-Co-V-B system alloys
  • Spark Plasma Sintering method

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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