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

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

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).",

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

author = "Hideaki Ono and Norihisa Waki and Munekatsu Shimada and Tatsuo Sugiyama and Akira Fujiki and Hiroshi Yamamoto and Masato Tani",

year = "2001",

month = jul,

doi = "10.1109/20.951232",

language = "English",

volume = "37",

pages = "2552--2554",

journal = "IEEE Transactions on Magnetics",

issn = "0018-9464",

publisher = "Institute of Electrical and Electronics Engineers Inc.",

number = "4 I",

note = "8th Joint Magnetism and Magnetic Materials -International Magnetic Conference- (MMM-Intermag) ; Conference date: 07-01-2001 Through 11-01-2001",

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TY - JOUR

T1 - Isotropic bulk exchange-spring magnets with 134 kJ/m3 prepared by spark plasma sintering method

AU - Ono, Hideaki

AU - Waki, Norihisa

AU - Shimada, Munekatsu

AU - Sugiyama, Tatsuo

AU - Fujiki, Akira

AU - Yamamoto, Hiroshi

AU - Tani, Masato

PY - 2001/7

Y1 - 2001/7

N2 - 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).

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).

KW - Bulk exchange-spring magnets

KW - Densification of melt-spun ribbons

KW - Isotropic magnetic properties

KW - Nd-Fe-Co-V-B system alloys

KW - Spark Plasma Sintering method

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