R-t-b sintered magnet
AssigneeProterial, Ltd.
InventorsYasutaka SHIGEMOTO, Futoshi KUNIYOSHI, Kouta SAITOU
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Abstract
This R-T-B sintered magnet has a main phase that comprises multiple R2T14B compound particles, and a grain boundary phase that is located between multiple R2T14B compound particles and that includes a two-particle grain boundary and grain boundary triple junctions. In a frequency histogram of grain boundary width measured from N reference points included in the two-particle grain boundary in a cross section which includes the orientation direction of the R-T-B sintered magnet in the plane thereof, when class intervals are determined so that the sixth lowest class represents the mode, the total frequency of three classes, i.e., the first, second, and third lowest classes, is not more than 12% of the whole.
Claims19
A sintered R-T-B based magnet (R is at least one of rare-earth elements and contains at least one of Nd and Pr with no exception, T is Fe or Fe and Co, and B is boron), comprising:
- a main phase formed of a plurality of R2T14B compound grains;
- and
- a grain boundary phase located between the plurality of R2T14B compound grains and including an intergranular grain boundary and a grain boundary triple junction,
- wherein in a frequency histogram of a grain boundary width measured from N-piece reference points included in the intergranular grain boundary that is located in a cross-section including, in a plane thereof, an alignment direction of the sintered R-T-B based magnet, in the case where widths of classes are determined such that the sixth class counted from the lowest class shows the mode, three classes that are the lowest class, the second lowest class and the third lowest class have a total frequency that is not higher than 12% of the frequency of all classes.
A sintered R-T-B based magnet (R is at least one of rare-earth elements and contains at least one of Nd and Pr with no exception, T is Fe or Fe and Co, and B is boron), comprising:
- a main phase formed of a plurality of R2T14B compound grains;
- and
- a grain boundary phase located between the plurality of R2T14B compound grains and including an intergranular grain boundary and a grain boundary triple junction,
- wherein in a frequency histogram of a grain boundary width measured from N-piece reference points included in the intergranular grain boundary that is located in a cross-section including, in a plane thereof, an alignment direction of the sintered R-T-B based magnet, the frequency at which the grain boundary width is not longer than 0.03 μm is not higher than 12% of the frequency of all classes.
Dependencies are inferred from the claim text.