Method for preparing permanent magnet material
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsHajime Nakamura, Takehisa Minowa
Life of this patent
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Abstract
A permanent magnet material is prepared by machining an anisotropic sintered magnet body having the compositional formula: Rx(Fe1-yCoy)100-x-z-aBzMa wherein R is Sc, Y or a rare earth element, M is Al, Cu or the like, to a specific surface area of at least 6 mm−1, heat treating in a hydrogen gas-containing atmosphere at 600-1,100° C. for inducing disproportionation reaction on the R2Fe14B compound, and continuing heat treatment at a reduced hydrogen gas partial pressure and 600-1,100° C. for inducing recombination reaction to the R2Fe14B compound, thereby finely dividing the R2Fe14B compound phase to a crystal grain size ≦1 μm.
Claims8
A method for preparing a permanent magnet material, comprising the steps of:
- providing an anisotropic sintered magnet body having the compositional formula:
- Rx(Fe1-yCoy)100-x-z-aBzMa wherein R is at least one element selected from rare earth elements inclusive of Sc and Y, M is at least one element selected from the group consisting of Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta, and W, x, y, z, and a indicative of atomic percentage are in the range:
- 10≦x≦15, 0≦y≦0.4, 3≦z≦15, and 0≦a≦11, said magnet body containing a R2Fe14B compound as a primary phase,
- machining the magnet body to a specific surface area of at least 6 mm−1,
- heat treating the magnet body which has been machined in a hydrogen gas-containing atmosphere at 600 to 1,100° C., for inducing disproportionation reaction on the R2Fe14B compound,
- continuing the heat treatment in an atmosphere having a reduced hydrogen gas partial pressure at 600 to 1,100° C., for inducing recombination reaction to the R2Fe14B compound, thereby finely dividing the R2Fe14B compound phase to a crystal grain size equal to or less than 1 μm, and
- washing the magnet body with at least one agent of alkalis, acids and organic solvents, after the recombination reaction treatment.
A method for preparing a permanent magnet material, comprising the steps of:
- providing an anisotropic sintered magnet body having the compositional formula:
- Rx(Fe1-yCoy)100-x-z-aBzMa wherein R is at least one element selected from rare earth elements inclusive of Sc and Y, M is at least one element selected from the group consisting of Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta, and W, x, y, z, and a indicative of atomic percentage are in the range:
- 10≦×≦15, 0≦y≦0.4, 3≦z≦15, and 0≦a≦11, said magnet body containing a R2Fe14B compound as a primary phase,
- machining the magnet body to a specific surface area of at least 6 mm−1,
- heat treating the magnet body which has been machined in a hydrogen gas-containing atomosphere at 600 to 1,100° C., for inducing disproportionation reaction on the R2Fe14B compound,
- contnuing the heat treatment in an atmosphere having a reduced hydrogen gas partial pressure at 600 to 1,100° C., for inducing recombination reaction to the R2Fe14B compound, thereby finely dividing the R2Fe14B compound phase to a crystal grain size equal to or less that 1 μm, and
- machining the magnet body, after the recombination reaction treatment.
Dependencies are inferred from the claim text.