| 摘要 |
PURPOSE:To contrive reduction in positional irregularity of magnetic characteristics by a method wherein permanent magnet grains, having the base which makes contact with a cooled substrate when it is high-speed quenched and the face opposing to the above-mentioned face on their surface, of 70wt.% or more are contained in permanent magnet powder. CONSTITUTION:One or more kinds of Y-containing rare-earth element and a molten alloy, containing F or Fe, Co and B, are brought to come in contact with a cooled substrate, they are high-speed quenched, and powder-like permanent magnet composed of thin band-like, thin piece-like or flat grains are obtained. This permanent magnet material is crushed using a bin mill in such a manner that breaking will be generated in the thickness direction of the material almost in parallel with the cooling direction. Accordingly, the crushed grains have the face contacting to the cooled substrate when the material is high-speed quenched and other face opposing to the above-mentioned face on their surface, and the grain-to-grain difference in magnetic characteristics can be eliminated. These crushed grains of 70wt.% or more is contained in the permanent magnet powder. As a result, the positional irregularity of magnetic characteristics can be reduced. |
