Patent ID: 6080245
Filing Date: 2000-06-27
Classification: B22F,C22C,H01F

Abstract:
A method for producing a rare earth permanent magnet, comprising the steps of:strip-casting a melt of a first alloy into a first alloy strip having a thickness of 1 mm or less;heat-treating said first alloy strip at 800-1100.degree. C. in an inert gas atmosphere or in vacuo; andpulverizing said heat-treated first alloy strip into a coarse powder of said first alloy,mixing said coarse powder of said first alloy and a coarse powder of a second alloy in a weight ratio of 70-99:1-30, said first alloy having a chemical composition, by weight, of 26.7-31% of R wherein R is at least one rare earth element including yttrium, 0.9-2.0% of B, 0.1-3.0% of M wherein M is at least one of Ga, Al and Cu and balance of Fe, and including a R.sub.2 Fe.sub.14 B phase, and said second alloy having a chemical composition, by weight, of 35-70% of R, 5-50% of Co, 0.1-30 % of M and balance of Fe;pulverizing the mixture of said coarse powder into a fine powder;recovering the fine powder in a solvent in an inert gas atmosphere in the form of a slurry;wet-compacting said slurry to form a green body while applying at least one magnetic field; andsintering said green body in a vacuum furnace.