METHOD FOR PRODUCING R-T-B BASED MAGNET

PROBLEM TO BE SOLVED : To provide a method for producing R-T-B based magnets having high Br and high HcJ, while reducing the content of heavy rare earth elements. SOLUTION : R3-T2-B-Cu-M2 based magnets having a molar ratio of [T2]/[B] of more than 14.0 can be obtained by a method which includes the steps of : preparing an R1-T1-B-Cu-M1 based alloy bulk body having a molar ratio of [T1]/[B] of 14.0 or less; preparing an R2-Ga-Fe-A based alloy; bringing at least a part of the R2-Ga-Fe-A based alloy into contact with at least a part of the surface of the R1-T1-B-Cu-M1 based alloy bulk body and performing a first heat treatment at a temperature of 700°C or above and 950°C or below; and subjecting the R1-T1-B-Cu-M1 based alloy bulk body having been subjected to the first heat treatment to a second heat treatment at a temperature of 450°C or above and 600°C or below. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2018, JPO&INPIT