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1987 Fiscal Year Final Research Report Summary

Development of High Performance Magnets by Crystallization of Amorphous RE-Fe-B Ribbons

Research Project

Project/Area Number 61850052
Research Category

Grant-in-Aid for Developmental Scientific Research

Allocation TypeSingle-year Grants
Research Field 電子材料工学
Research InstitutionCHUBU UNIVERSITY and NAGASAKI UNIVERSITY

Principal Investigator

NARITA Kenji  Professor, Faculty of Engineering, CHUBU UNIVERSITY, 工学部, 教授 (90037664)

Co-Investigator(Kenkyū-buntansha) 清水 泰式  長崎大学, 工学部, 助手 (60039667)
FUKUNAGA Hirotoshi  Associate Professor, Faculty of Engineering, NAGASAKI UNIVERSITY, 工学部, 助教授 (10136533)
TERADA Hiroshi  Lecturer, Faculty of Engineering, CHUBU UNIVERSITY, 工学部, 講師
KATO Akira  Associate Professor, Faculty of Engineering, CHUBU UNIVERSITY, 工学部, 助教授 (00113085)
SHIMIZU Yasukazu  Research Assistant, Faculty of Engineering, NAGASAKI UNIVERSITY
Project Period (FY) 1986 – 1987
KeywordsAmorphous / Crystallization / RE-Fe-B / Nd-Fe-B
Research Abstract

Amorphous ND_x Fe 100-(x+y)B_y (13.5(less than or equal)X(less than or equal)10) ribbons were prepared by the single roller quenching method and crystallized into magnets with sub-(micrn)m micro-structures by flash annealing at 700-750゜C. The coercivity measured under an applied field of 20KOe is not affected remarkably by B content, but devreases abruptly with decreasing Nd content. The coercivities in excess of 15KOe are achieved in magnets with x(greater than or equal)15. The maximum (BH)_<max> can be obtained in Nd_<15> Fe_<75> B_<10> magnet. However, the dependence of the coercivity on the maximum lower B content if applied fields larger than 20KOe are applied.
All the magnets magnetize rapldly at low fields, indicating the existence of domain walls shich are initially free to move. This would be due to the fact that the grain size is large compared with taht of rapidly solidified magnets.
In all the magnets crystallized under the best condition, only two magnetic phases, Nd_2 Fe_<14> B and <alpha>-Fe, are detected by the thermo-magnetic analysis. X-ray diffraction analysis indicates that the lack of the Nd-rich phase results in devrease in the coercivity similarly to shintered magnets.
The above results suggest that crystallized magnets have magnetic and structural properties which differ from tghose reported on the rapidly solidified magnets, and seem to be hardened by the same mechanism as sintered magnets.

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Published: 1989-03-30  

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