Production of Nd-Fe-Co-B magnet powders having high Br by modified HDDR process

Koichiro Morimoto; Yoshinari Ishii; Ryoji Nakayama; Masaru Itakura; Noriyuki Kuwano; Kensuke Oki

doi:10.2497/jjspm.46.51

Production of Nd-Fe-Co-B magnet powders having high B_r by modified HDDR process

Koichiro Morimoto, Yoshinari Ishii, Ryoji Nakayama, Masaru Itakura, Noriyuki Kuwano, Kensuke Oki

Materials Physics and Engineering

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

It is well established that the hydrogenation-decomposition-desorption-recombination (HDDR) process can produce anisotropic Nd₂Fe₁₄B-based magnet powders having high coercivities. In this study, we investigated effects of the intermediate argon (IA) treatment, where alloys are annealed under argon atmosphere after hydrogenation in the HDDR process, on magnetic properties of Nd_12.6Fe_bal.Co_17.4B_6.5Zr_0.1Ga_0.3 magnet powders. It was found that magnetic anisotropy of magnet powders is improved with IA treatment time. On the other hand, their coercivities are decreased by the IA treatment longer than 10min. The magnetic properties of the magnet powders with diameters of 100-212μm produced through the IA treatment for 10min are as follows: B_r = 1.38T, H_cJ = 1000kA/m and (BH)_max = 334kJ/m³. Transmission electron microscope observation revealed that change in microstructures such as rapid growth of α-(Fe, Co) matrix, disappearance of (Fe, Co)₂B and formation of a new phase (TE phase) occur in hydrogenated alloys during the IA treatment.

Original language	English
Pages (from-to)	51-56
Number of pages	6
Journal	Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Volume	46
Issue number	1
DOIs	https://doi.org/10.2497/jjspm.46.51
Publication status	Published - 1999

All Science Journal Classification (ASJC) codes

Mechanical Engineering
Industrial and Manufacturing Engineering
Metals and Alloys
Materials Chemistry

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title = "Production of Nd-Fe-Co-B magnet powders having high Br by modified HDDR process",

abstract = "It is well established that the hydrogenation-decomposition-desorption-recombination (HDDR) process can produce anisotropic Nd2Fe14B-based magnet powders having high coercivities. In this study, we investigated effects of the intermediate argon (IA) treatment, where alloys are annealed under argon atmosphere after hydrogenation in the HDDR process, on magnetic properties of Nd12.6Febal.Co17.4B6.5Zr0.1Ga0.3 magnet powders. It was found that magnetic anisotropy of magnet powders is improved with IA treatment time. On the other hand, their coercivities are decreased by the IA treatment longer than 10min. The magnetic properties of the magnet powders with diameters of 100-212μm produced through the IA treatment for 10min are as follows: Br = 1.38T, HcJ = 1000kA/m and (BH)max = 334kJ/m3. Transmission electron microscope observation revealed that change in microstructures such as rapid growth of α-(Fe, Co) matrix, disappearance of (Fe, Co)2B and formation of a new phase (TE phase) occur in hydrogenated alloys during the IA treatment.",

author = "Koichiro Morimoto and Yoshinari Ishii and Ryoji Nakayama and Masaru Itakura and Noriyuki Kuwano and Kensuke Oki",

year = "1999",

doi = "10.2497/jjspm.46.51",

language = "English",

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pages = "51--56",

journal = "Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy",

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T1 - Production of Nd-Fe-Co-B magnet powders having high Br by modified HDDR process

AU - Morimoto, Koichiro

AU - Ishii, Yoshinari

AU - Nakayama, Ryoji

AU - Itakura, Masaru

AU - Kuwano, Noriyuki

AU - Oki, Kensuke

PY - 1999

Y1 - 1999

N2 - It is well established that the hydrogenation-decomposition-desorption-recombination (HDDR) process can produce anisotropic Nd2Fe14B-based magnet powders having high coercivities. In this study, we investigated effects of the intermediate argon (IA) treatment, where alloys are annealed under argon atmosphere after hydrogenation in the HDDR process, on magnetic properties of Nd12.6Febal.Co17.4B6.5Zr0.1Ga0.3 magnet powders. It was found that magnetic anisotropy of magnet powders is improved with IA treatment time. On the other hand, their coercivities are decreased by the IA treatment longer than 10min. The magnetic properties of the magnet powders with diameters of 100-212μm produced through the IA treatment for 10min are as follows: Br = 1.38T, HcJ = 1000kA/m and (BH)max = 334kJ/m3. Transmission electron microscope observation revealed that change in microstructures such as rapid growth of α-(Fe, Co) matrix, disappearance of (Fe, Co)2B and formation of a new phase (TE phase) occur in hydrogenated alloys during the IA treatment.

AB - It is well established that the hydrogenation-decomposition-desorption-recombination (HDDR) process can produce anisotropic Nd2Fe14B-based magnet powders having high coercivities. In this study, we investigated effects of the intermediate argon (IA) treatment, where alloys are annealed under argon atmosphere after hydrogenation in the HDDR process, on magnetic properties of Nd12.6Febal.Co17.4B6.5Zr0.1Ga0.3 magnet powders. It was found that magnetic anisotropy of magnet powders is improved with IA treatment time. On the other hand, their coercivities are decreased by the IA treatment longer than 10min. The magnetic properties of the magnet powders with diameters of 100-212μm produced through the IA treatment for 10min are as follows: Br = 1.38T, HcJ = 1000kA/m and (BH)max = 334kJ/m3. Transmission electron microscope observation revealed that change in microstructures such as rapid growth of α-(Fe, Co) matrix, disappearance of (Fe, Co)2B and formation of a new phase (TE phase) occur in hydrogenated alloys during the IA treatment.

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Production of Nd-Fe-Co-B magnet powders having high B_r by modified HDDR process

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