METHOD OF PRODUCING R-T-B-BASED PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To enhance the orientation of a porous magnet produced by using the HDDR method. SOLUTION : A molding having a density of 3.5-5.2 g/cm3 and magnetic anisotropy is produced by molding powder of an R-T-B-based alloy (R is a rare earth element containing 50 atom% or more of Nd and/or Pr, T is Fe, or Fe and Co) having 50%volume center grain size (D50) of 1-10 μm, and including a R2T14B phase, in a magnetic field. This method includes a first heat treatment step for progressing the sintering of the molding by heating and holding the molding in vacuum or an argon atmosphere, a second heat treatment step for progressing the hydrogenation and disproportionation reaction, and a third heat treatment step for forming a porous body by progressing the dehydrogenation and recombination reaction. Sintering is progressed by the first heat treatment step, so that the density of the molding is 5.7-6.4 g/cm3 when the second heat treatment step is started. COPYRIGHT : (C)2014, JPO&INPIT