METHOD OF MANUFACTURING ANTICORROSIVE R-Fe-B-BASED SINTERED MAGNET

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PROBLEM TO BE SOLVED : To provide a method of manufacturing an R-Fe-B-based sintered magnet which contains only a small amount of RH or does not contain the RH, and has an excellent corrosion resistance. SOLUTION : The method of manufacturing an R-Fe-B-based sintered magnet includes a step for performing heat treatment at 200-450°C in an atmosphere where the oxygen partial pressure is 1×103-1×105 Pa, the water vapor partial pressure is lower than 1000 Pa and the ratio of the oxygen partial pressure and the water vapor partial pressure (oxygen partial pressure/water vapor partial pressure) is 1-20000 for an R-Fe-B-based sintered magnet containing 4.5 mass% or less of heavy rare-earth elements (at least one kind selected from RH : Dy and Tb). Temperature of the magnet is lowered from the heat treatment temperature at an average cooling rate of 650°C/hour or higher at least until 100°C. COPYRIGHT : (C)2012, JPO&INPIT