METHOD FOR MANUFACTURING RARE EARTH PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To provide a method of efficiently deoiling and sintering a rare earth permanent magnet compact formed by a wet forming method.SOLUTION : In the process of forming the rare earth permanent magnet, an R-Fe-B (R is not less than a kind of rare earth element including Y) base permanent magnet coarse powder is pulverized in the gas flow of N2 or Ar that contains oxygen of ≤0.01%. Fine powder obtained is collected in a mineral oil belonging to the fourth second petroleum having inflammation point of ≥21°C and <70°C as defined by the fire protection law, or in a synthetic oil to directly make a slurry in one atomic pressure without contacting to atmosphere. The slurried raw material was wet formed in magnetic field. The obtained compact was introduced into a deoling chamber and the chamber was evacuated. Evacuation was stopped and an inert gas was introduced into the deoiling chamber. The compact was heated while mixing the introduced inert gas. Further, the deoil chamber was evacuated and the compact was heated for deoiling. The deoiled formed body is sintered.COPYRIGHT : (C)2008, JPO&INPIT