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

doi:10.1109/20.951232

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 journal › Conference article › peer-review

37 Citations (Scopus)

Abstract

Densification of exchange-spring magnet ribbons of Nd_xFe_85-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, B_r decreased from 1.05 T to 0.82 T and H_cJ 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 language	English
Pages (from-to)	2552-2554
Number of pages	3
Journal	IEEE Transactions on Magnetics
Volume	37
Issue number	4 I
DOIs	https://doi.org/10.1109/20.951232
Publication status	Published - 2001 Jul
Externally published	Yes
Event	8th Joint Magnetism and Magnetic Materials -International Magnetic Conference- (MMM-Intermag) - San Antonio, TX, United States Duration: 2001 Jan 7 → 2001 Jan 11

Keywords

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

Access to Document

10.1109/20.951232

Cite this

Isotropic bulk exchange-spring magnets with 134 kJ/m³ prepared by spark plasma sintering method. / Ono, Hideaki; Waki, Norihisa; Shimada, Munekatsu; Sugiyama, Tatsuo; Fujiki, Akira; Yamamoto, Hiroshi; Tani, Masato.

In: IEEE Transactions on Magnetics, Vol. 37, No. 4 I, 07.2001, p. 2552-2554.

Research output: Contribution to journal › Conference article › peer-review

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abstract = "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).",

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AB - 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).

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