日本金属学会誌

J. Japan Inst. Metals, Vol. 59, No. 1 (1995),
pp. 103-107

Effects of Dy Compound Powder Addition on the Microstructures andthe Magnetic Properties of Nd-Fe-B Sintered Magnets

Yukiko Itou1, Yasuji Fukui1, Takashi Kitayama1,Yoshiro Iwama1, Takao Kobayashi2 and Yoshio Kato2

1Aichi Steel Works LTD, Tokai
2Toyota Central Laboratories, INC, Aichi

Abstract:

Microstructures and magnetic properties of the Nd-Fe-B magnets sintered by adding Dy compound powder are examined. The Nd15Fe77B8 powders are mixed with Dy40Al30Cu30 compound powders and then sintered, followed by an appropriate heat treatment. It is found by EPMA analysis that the R2Fe14B main phase is composed of a Dy-poor core region surrounded with a Dy-rich shell region. As a result, the coercivity is increased and the value is higher than that of the magnet sintered by conventional process, in which there is a homogeneous distribution of Dy. The effect is enhanced by thinning the Dy-rich region by controlling the diameter of magnet powder of Nd15Fe77B8, as well as the sintering time.


(Received March 16, 1994)

Keywords:

neodymium-iron-boron, permanent magnet, magnetic property, dysprosium compound addition, electron probe microanalyzer, microstructure


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