METHOD FOR PREPARING PERMANENT MAGNET MATERIAL

摘要

A method for manufacturing a permanent magnet material is provided to off a thin-film typed permanent magnet and to achieve favorable self-characteristic of the permanent magnet by continuously heat treating an anisotropic sintered magnet body for inducing disproportionation reaction and recombination reaction. A method for manufacturing a permanent magnet material comprises the steps: machining an anisotropic sintered magnet body to have s specific surface area of at least 6mm-1; heat treating the machined magnet body and the powder in a hydrogen gas-containing atmosphere at 600 to 1100°C for inducing disproportionation reaction on the R^12Fe14B compound; and heat treating in an atmosphere with lowered hydrogen gas partial pressure at 600 to 1100°C for inducing recombination reaction to the R^12Fe14B compound and finely dividing the crystal particle of the R^12Fe14B compound less than 1 mum for absorbing at least one of R^2, R^3, R^4 to the magnet body. The machined magnet sintered magnet body is cleaned by one of alkali, acid or organic solvent before disproportionation treatment. The compositional formula is the Rx(Fe1_yCoy)100-x-z-aBzMa.