DocumentCode
819222
Title
The disproportionation of Nd2Fe14B under hydrogen in Nd-Fe-B alloys
Author
Book, D. ; Harris, I.R.
Author_Institution
Sch. of Metall. & Mater., Birmingham Univ., UK
Volume
28
Issue
5
fYear
1992
fDate
9/1/1992 12:00:00 AM
Firstpage
2145
Lastpage
2147
Abstract
The kinetics of the disproportionation reaction in which the Nd 2Fe14B phase forms Fe, Nd-hydride, and Fe2 B under hydrogen has been investigated by thermopiezic analysis. These studies have shown that the disproportionation temperature is dependent on grain size, and is considerably lower for Nd-Fe-B alloys with submicron grain sizes when compared with the case material. Thus, melt-spun material disproportionates at a temperature about 300°C below that of cast alloy (at a heating rate of 1°C/min). In addition, the amount of Nd2Fe14B phase in the alloy can be related to the temperature range over which the reaction occurs and to the amount of Fe and Fe2B that forms as a result of the disproportionation reaction. The latter can be monitored by measuring the magnetization of the disproportionated material
Keywords
boron alloys; dissociation; ferromagnetic properties of substances; grain size; iron alloys; magnetisation; neodymium alloys; permanent magnets; reaction kinetics; thermal analysis; H2 atmosphere; Nd-Fe-B alloys; Nd2Fe14B; cast alloy; disproportionation reaction kinetics; disproportionation temperature; grain size; magnetization; melt-spun material; thermopiezic analysis; Grain size; Heating; Hydrogen; Iron alloys; Kinetic theory; Magnetic materials; Monitoring; Neodymium; Temperature dependence; Temperature distribution;
fLanguage
English
Journal_Title
Magnetics, IEEE Transactions on
Publisher
ieee
ISSN
0018-9464
Type
jour
DOI
10.1109/20.179424
Filename
179424
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