For the rare earth magnet alloy and manufacturing method thereof

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PROBLEM TO BE SOLVED : To improve the magnetic properties of an alloy by crystallizing out R2 Fe14 B columnar crystals (R denotes rare earth elements including Y) as the main phases in such a manner that the dimensions are made large and the volume ratio of the crystallized region is made high and crystallizing out phases in which the content of R in an eutectic region having the R content higher than that is made smaller in such a manner that the dimensions thereof are made small. SOLUTION : A cast ingot of an alloy contg. R, T (transition metals essentially consisting of Fe) and B as fundamental components is heated at 800 to 1150 deg.C and is thereafter heated in the temp. region of 800 to 600 deg.C at >=5 deg.C/sec. In this way, a rare earth magnet alloy contg. R2 Fe14 B columnar crystals 1 as the main phases and contg. an eutectic region 2 having the R content higher than that is obtd. In the R2 Fe14 B columnar crystals 1 as the main phases of this alloy, the dimensions in the direction of the major axis are controlled to >=50 μm, the dimensions in the direction of the minor axis to >=10 μm, and the volume ratio of the crystallized region thereof to >=70%. Moreover, the eutectic region 2 is composed of partial phases 3 relatively high in the R content and phases 4 crystallized into a bar shape and more small in the R content, and also, the dimensions in the direction of the minor axis in the phases 4 are controlled to <=3 μm.