R-T-B alloy slug for sintered magnet, the magnet and its manufacturing method

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PROBLEM TO BE SOLVED : To provide an alloy slug for R-T-B-based rare-earth magnet, which has fine R-rich phases adequately dispersed therein, and contains large columnar crystals. SOLUTION : The slug of the alloy for the R-T-B-based sintered magnet includes the R2T14B columnar crystal and the R-rich phase (where R is at least one of rare earth elements including Y; T is Fe, or Fe and at least one of transition metal elements except Fe; and B is boron, or boron and carbon), wherein the R-rich phases are dispersed approximately in a linear form or bar form (though these widths are determined as minor axes) when the cross section is observed in as a cast state, and the R2T14B columnar crystal grains with a length of 500 μm or longer in a major axis direction and a length of 50 μm or longer in a minor axis direction occupy 10% or more region by an area rate with respect to the total region in the alloy. COPYRIGHT : (C)2006, JPO&NCIPI