RFeB-BASED SINTERED MAGNET PRODUCTION METHOD AND RFeB-BASED SINTERED MAGNETS

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The present invention addresses the problem of providing a method for easily producing RFeB-based sintered magnets that have high coercivity and suppress the effects of eddy currents during use, said RFeB-based sintered magnets comprising unit sintered magnets that are firmly joined to each other. The method for producing RFeB-based sintered magnets obtained by joining at least two unit sintered magnets (11) to each other on flat joining surfaces, said unit sintered magnets (11) comprising crystal grains with a main phase of R2Fe14B containing a light rare earth element (RL) comprising neodymium and/or praseodymium as a main rare earth element (R). A grain boundary diffusion process is conducted by heating a paste (12) obtained by mixing a metal powder containing a heavy rare-earth element (RH) comprising at least one of dysprosium, holmium and terbium, with an organic material, while the paste is brought into contact with the joining surfaces in such a manner as to sandwich the paste between the two unit sintered magnets (11). Coercivity is increased by the grain boundary process, and an oxide or the like of RH and/or RL is formed on the grain boundaries of the unit sintered magnets (11), thus enabling the effects of eddy currents to be suppressed during use, and allowing the unit sintered magnets (11) to firmly join to each other.