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

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4 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)51-56
Number of pages6
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Issue number1
Publication statusPublished - 1999

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry


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