| 简介 |
PROBLEM TO BE SOLVED : To provide an R-Fe-B rare-earth sintered magnet effectively utilizing a heavy rare-earth element RH, and diffusing the heavy rare-earth element RH in the outer shell of a main-phase crystal particle over the whole of a magnet even with the comparatively large thickness.
SOLUTION : The R-Fe-B rare-earth sintered magnet has as a main phase an R2Fe14B-component crystal particle containing a light rare-earth element RL (at least one kind of Nd and Pr) as a main rare-earth element R, and contains a heavy rare-earth element RH (at least one kind selected out of a group comprising Dy, Ho and Tb). A surface-layer region, 100 μm deep from the surface of the magnet, has the concentrated layer of the heavy rare-earth element RH positioned in the outer shell of the R2Fe14B-component crystal particle, with the concentration of the heavy rare-earth element RH heavier than that in the middle of the R2Fe14B-component crystal particle; and a composition with the concentration of the heavy rare-earth element RH in the middle of the R2Fe14B-composition crystal particle with the concentration equal to or lower than 1 atm% of the heavy rare-earth element RH in the triple point of the crystal particle.
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