PROCESS FOR PRODUCING ALLOY SLAB FOR RARE-EARTH SINTERED MAGNET, ALLOY SLAB FOR RARE-EARTH SINTERED MAGNET AND RARE-EARTH SINTERED MAGNET

摘要

A process for producing an alloy slab for rare-earth sintered magnet, in which homogenization of R-rich region and 2-14-1 phase dendrite spacings, sizes, orientations, shapes, etc. can be attained with the generation of chill crystal suppressed, which alloy slab facilitates pulverization into uniform particle size in the step of pulverization for production of rare-earth sintered magnet and enables control of contraction ratio of an alloy powder compact after the pulverization; an alloy slab for rare-earth sintered magnet produced by the process; and a rare-earth sintered magnet excelling in magnetic properties. There is provided a process comprising the step of preparing a melt of alloy composed of R such as a rare earth metal element, B and Fe together with the balance of M and the step of feeding the alloy melt to cooling rolls with surfaces having multiple linear solidification nucleus generation inhibiting parts capable of inhibiting the generation of dendrite, etc. and solidification nucleus generating parts capable of generation of dendrite wherein the line width of solidification nucleus generation inhibiting parts has a region of > 100 mum, thereby effecting cooling solidification.