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Relations of Corrosion Resistance, Coercivity, and Magnetizability of Modified Nd-Fe-B Sintered Magnets to Their Microstructure

Published online by Cambridge University Press:  15 February 2011

Satoshi Hirosawa ,
Koki Tokuhara ,
Shuji Mino ,
Toshiyuki Matsui ,
Kenji Morii  and
Yutaka Nakayama
Satoshi Hirosawa
Affiliation:
Sumitomo Special Metals Co., Ltd., 2-15-17 Egawa, Shimamotocho, Mishimagun, Osaka 618, Japan
Koki Tokuhara
Affiliation:
Sumitomo Special Metals Co., Ltd., 2-15-17 Egawa, Shimamotocho, Mishimagun, Osaka 618, Japan
Shuji Mino
Affiliation:
Sumitomo Special Metals Co., Ltd., 2-15-17 Egawa, Shimamotocho, Mishimagun, Osaka 618, Japan
Toshiyuki Matsui
Affiliation:
College of Engineering, Osaka Prefectural University, 4-804 Mozu-Ume-Machi, Sakai 591, Japan.
Kenji Morii
Affiliation:
College of Engineering, Osaka Prefectural University, 4-804 Mozu-Ume-Machi, Sakai 591, Japan.
Yutaka Nakayama
Affiliation:
College of Engineering, Osaka Prefectural University, 4-804 Mozu-Ume-Machi, Sakai 591, Japan.
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Abstract

Brief reviews on corrosion and coercivity mechanisms of sintered Nd-Fe-B magnets are given. Results of recently undertaken transmission electron microscopic study of Nd15 - Fe78-xCoxB7 sintered magnets (x = 3, 6 and 10) are presented. Micro-beam electron diffraction patterns obtained from Nd-Co phases in these magnets could be indexed according only to an orthorhombic cell of Nd3 Co among the binary Nd-Co compounds for x = 3 to 10. Relations of coercivity and magnetizability of this type of magnets to their microstructure are discussed in connection to the effects of V or Mo addition which are to enhance coercivity and to improve magnetizability. It is suggested that a decrease in the local demagnetization effects resulting from a decrease in the width of the grain size distribution due to these-additives is the origin of the enhancement of coercivity and the improvement of magnetizability.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 232: Symposium T – Magnetic Materials: Microstructure and Properties , 1991 , 275
Copyright
Copyright © Materials Research Society 1991

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References

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