RAW MATERIAL ALLOY FOR RARE EARTH MAGNET, PRODUCTION METHOD THEREFOR, AND ALLOY POWDER FOR RARE EARTH MAGNET

摘要

PROBLEM TO BE SOLVED: To provide a raw material alloy for an R₂Fe₁₄B based rare earth magnet which has excellent magnetic properties, to provide the alloy powder, and to provide a production method by which they can efficiently be produced.;SOLUTION: The raw material alloy for a rare earth magnet has a composition comprising, by mass, 27.6 to 33.0% R consisting of at least one kind selected from rare earth metal elements including Y, 0.94 to 1.30% boron, and the balance M including iron. The average spacing between R-enriched phases in the alloy is 3 to 12 μm. The value obtained by dividing the standard deviation in the spacing between the R-enriched phases by the average spacing between the R-enriched phases is ≤0.25. Also, the volume ratio of the R₂Fe₁₄B based main phase is ≥88 vol.%. In the production method, the molten metal having the alloy composition is cooled and solidified on a roll by a strip casting method, the cooled and solidified alloy slab is peeled from the roll, thereafter, control is performed so as to have specified heat history, and further, cooling is carried out.;COPYRIGHT: (C)2004,JPO