Rare earth elements - manufacturing method of transition elements -B based magnets

摘要

PURPOSE:To produce a permanent magnet excellent in magnetic properties by sealing an ingot of alloy consisting of rare earth elements, transition elements and B in a metallic capsule via a lubricant, applying hot rolling by two or more passes to the above, and then spheroidizing the structure by means of heat treatment at specific temp. CONSTITUTION:An ingot of an alloy containing rare earth elements, transition metals such as Fe, Co and Ni, by atom, 8 to 25% 65 to 90% and 2 to 10%, respectively, and B is sealed by the use of a lubricant such as BN, in a capsule made of, e.g. stainless steel having a melting point higher than that of this alloy, which is hated up to 750-1150 deg.C and subjected to hot rolling at least by two or more passes so that the total draft is regulated to =30%. Subsequently, the above capsule is heat-treated at 800-1150 deg.C and further heat-treated at 400 to 800 deg.C to undergo the spheroidization of eutectic structure, followed by slow cooling through the temp. region from 700 to 200 deg.C at =10 deg.C/min cooling rate. Finally the metallic capsule is peeled off and removed, by which the permanent magnet excellent in magnetic properties can be produced.