Magnetic anisotropy and excellent thermal stability and a manufacturing method therefor

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PROBLEM TO BE SOLVED : To provide a powder of a rare-earth magnet superior in magnetic anisotropy and thermal stability, and to provide a manufacturing method therefor. SOLUTION : The powder of the rare-earth magnet has a chemical composition comprising 5-20% R, (wherein R represents one or more elements among rare earth elements including Y and excluding Dy and Tb), one or two elements of Dy and Tb in an amount of 0.01-5%, 3-20% B, and 0.1-50% Co and 0.001-5% M, as needed, and the balance Fe with unavoidable impurities; has a particle size of 10-1, 000 μm by average; and has a layer mainly containing one or two elements of Dy and Tb and having a thickness of 0.05-50 μm so as to cover a 70% or larger area of the whole surface. The above Dy-Tb-rich layer contains such a high concentration of one or two elements of Dy and Tb that when they are detected by wavelength dispersive X-ray spectroscopy, the maximum intensity in the layer is 1.2 to 5 times higher than average intensity in a central particle region within the 1/3 length of the particle diameter. COPYRIGHT : (C)2005, JPO&NCIPI