MANUFACTURING METHOD OF RARE-EARTH SINTERED MAGNET

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PROBLEM TO BE SOLVED : To provide a manufacturing method of a rare-earth sintered magnet capable of restraining a decrease in magnetic characteristics, and obtaining low-cost and high-characteristic rare-earth sintered magnet. SOLUTION : Fine pulverization and formation in a magnetic field are performed under a low-oxygen atmosphere having an oxygen concentration of not more than 100 ppm. In this case, before the fine pulverization, a low-viscosity lubricant of not more than 10 mPa s, such as octanoic acid, octanoic acid ethyl, octanoic acid methyl, lauric acid ethyl, and lauric acid butyl is added to raw material alloy powder, thus restraining the amount of nitrogen contained in the powder and suppressing a decrease in magnetic characteristics. Processes for fine pulverization and formation in a magnetic field are performed in a nitrogen gas atmosphere, thus reducing oxygen concentration to not more than 100 ppm and restraining manufacturing costs. COPYRIGHT : (C)2008, JPO&INPIT