MATERIAL POWDER FOR RARE EARTH SINTERED MAGNET AND ITS PRODUCTION METHOD, AND METHOD OF MANUFACTURI

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PROBLEM TO BE SOLVED : To provide a granulation technology which prevents the oxidation of material powder while keeping the high debinding property thereof.SOLUTION : A method of production material powder for a rare earth sintered magnet comprises a process of producing slurry which contains primary alloy grains having predetermined proportions of components and also contains, as a dispersion medium, alcohol wherein polyvinyl alcohol having a degree of saponification of 50 mol% or less is dissolved; and a process of spray-drying the slurry. Since the alcohol is used as the dispersion medium of the slurry for the purpose of granulation and such polyvinyl alcohol as to have a degree of saponification of 50 mol% or less is used as a binder dissolved into the alcohol, an amount of oxygen is reduced as opposed to the case that water is used as the dispersion medium. Therefore, chargeability into a metal mold can be improved while suppressing degradation in magnetic characteristics. Moreover, the use of the polyvinyl alcohol as the binder facilitates debinding.