Patent ID: 7141126

Claim:
A method for manufacturing an R—Fe—B rare earth magnet, comprising the steps of: preparing a rare earth alloy powder having an oxygen content in a range of 50 wt. ppm to 4000 wt. ppm and a nitrogen content in a range of 150 wt. ppm to 1500 wt. ppm and embrittling an R—Fe—B rare earth alloy by hydrogen occlusion and milling the embrittled alloy; compacting the rare earth alloy powder by dry pressing to produce a compact; and, sintering the compact, wherein the step of sintering the compact includes: a first step of retaining the compact at a temperature in a range of 700° C. to less than 1000° C. for a period of time in a range of 10 minutes to 420 minutes and releasing hydrogen outside the compact so that the amount of hydrogen contained in sintered magnet is in a range of 10 wt. ppm to 100 wt. ppm; and a second step of permitting the proceeding of sintering at a temperature in a range of 1000° C. to 1200° C., and the average crystal grain size of the rare earth magnet after the sintering is in a range of 3 μm to 9 μm.