| 简介 |
PROBLEM TO BE SOLVED : To suppress magnetic property deterioration of a magnetic powder material by heat treatment with a usage amount of a fluorine compound reduced.
SOLUTION : A fluorine concentration is higher in an area near the surface of the magnet than that in the magnet center in a sintered magnet of a rare earth iron boron system constituted by a main phase crystal grain and a crystal grain boundary part which encloses the surrounding of the main phase crystal grain. The concentration of one kind of metallic element selected from among elements excluding rare earth elements, carbon and boron from elements belonging to Group 2 to Group 16 is higher in an area near the surface of the magnet than that in the magnet center. A carbonic acid fluoride containing Dy and the metallic element is formed in the crystal grain boundary part in an area which is apart by a distance of 1 μm or more from the magnetic surface, and a concentration of carbon is higher than a concentration of the metallic element in an area which is apart by a distance of 1 μm to 500 μm from the magnetic surface.
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