SLAB FOR R-Fe-B-C BASED MAGNET ALLOY HAVING EXCELLENT CORROSION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a method for producing an R-Fe-B-C based magnet alloy slab in which the reduction of the degree of orientation, pulverization in grinding in its making into a magnet, and the oxidation of the powder can be prevented, and which has excellent corrosion resistance and magnetic properties for solving the problems of the slab obtained from the molten metal of a magnet alloy by rapidly cooling rollers.;SOLUTION: The molten metal of an R-Fe-B-C based alloy in which B+C=6 to 10 at.% (wherein, B: 2 to 6 at.%, and C: 4 to 8 at.%) is melted. After that, the molten metal is subjected to primary cooling by rapid cooling rollers at a specified cooling rate, and subsequently, the slab removed from the rollers is subjected to secondary cooling to a solidus temperature or lower at a specified cooling rate to obtain a rapidly cooled slab with a homogeneous structure in which R2Fe14(B1-xCx) type dendritic or columnar crystals having a minor axis grain size with specified dimensions and a minor axis grain size distribution and a specified R rich phase are finely dispersed, so that the R-Fe-B-C based magnet alloy slab having excellent corrosion resistance and magnetic properties can be produced.;COPYRIGHT: (C)2002,JPO