MANUFACTURING METHOD OF SINTERED RARE-EARTH MAGNET

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PROBLEM TO BE SOLVED : To improve molded body strength by means of molding in a magnetic field by suppressing the degradation in magnetic characteristics. SOLUTION : This method comprises : a step of coarse crushing a raw material alloy of an Nd-Fe-B-based sintered magnet; a step of pulverizing the coarse-crushed powder obtained in the coarse crushing step by a jet mill; a step of pressure molding the pulverized powder obtained in the pulverizing step while applying a magnetic field to the powder; and a step of sintering the molded body obtained in the pressure molding step. In the pulverizing step, an impingement jet mill is used and the amount of oxygen of its pulverization atmosphere is specified to 8, 000 to l5, 000 ppm. The pulverized powder preferably satisfies the conditions of an average grain size D50=3.0 to 6.0 μm, D10/D50=0.35 to 0.55, D90/D50=1.80 to 2.05. COPYRIGHT : (C)2008, JPO&INPIT