发明名称 |
Method for producing powder for magnet |
摘要 |
Provided are a method for producing powder for a magnet, and methods for producing a powder compact, a rare-earth-iron-based alloy material, and a rare-earth-iron-nitrogen-based alloy material. Magnetic particles constituting the powder each have a texture in which grains of a phase of a hydride of a rare-earth element are dispersed in a phase of an iron-containing material. The uniform presence of the phase of the iron-containing material in each magnetic particle results in powder having excellent formability, thereby providing a powder compact having high relative density. The powder is produced by heat-treating rare-earth-iron-based alloy powder in a hydrogen atmosphere to separate the rare-earth element and the iron-containing material and then forming a hydride of the rare-earth element. The powder is compacted. The powder compact is heat-treated in vacuum to form a rare-earth-iron-based alloy material. The rare-earth-iron-based alloy material is heat-treated in a nitrogen atmosphere to form a rare-earth-iron-nitrogen-based alloy material. |
申请公布号 |
US9435012(B2) |
申请公布日期 |
2016.09.06 |
申请号 |
US201514979111 |
申请日期 |
2015.12.22 |
申请人 |
Sumitomo Electric Industries, Ltd. |
发明人 |
Maeda Toru |
分类号 |
H01F1/22;C22C33/02;C22C38/00;H01F1/055;H01F1/059;H01F1/08;H01F41/02;C22C1/10;B22F3/02;B22F9/00;C21D1/74;C21D6/00;H01F1/20 |
主分类号 |
H01F1/22 |
代理机构 |
Ditthavong & Steiner, P.C. |
代理人 |
Ditthavong & Steiner, P.C. |
主权项 |
1. A method for producing a rare-earth-iron-nitrogen-based alloy material used for a rare-earth magnet, the method comprising:
a preparation step of preparing an alloy powder composed of a rare-earth-iron-based alloy that contains a rare-earth element serving as an additional element; a hydrogenation step of heat-treating the rare-earth-iron-based alloy powder in a hydrogen element-containing atmosphere at a temperature equal to or higher than a disproportionation temperature of the rare-earth-iron-based alloy to form a powder for a magnet, wherein the powder is constituted by magnetic particles, each of the magnetic particles contains a hydride of a rare-earth element in an amount of less than 40% by volume and the balance being an iron-containing material that contains Fe, wherein a phase of the hydride of the rare-earth element is adjacent to a phase of the iron-containing material, and an interval between adjacent phases of the hydride of the rare-earth element with the phase of the iron-containing material provided therebetween is 3 μm or less; a coating step of coating an antioxidation layer on a surface of each of the magnetic particles, the antioxidation layer including a low-oxygen-permeability layer composed of a material having an oxygen permeability coefficient at 30° C. of less than 1.0×10−11 m3·m/(s·m2·Pa) and a low-moisture-permeability layer composed of a material having a moisture permeability coefficient at 30° C. of less than 1000×10−13 kg/(m·s·MPa), the low-oxygen-permeability layer is polyester or polyvinyl chloride; a compacting step of compacting the powder for the magnet to provide a powder compact having a relative density of 85% or more; and a dehydrogenation step of heat-treating the powder compact in an inert atmosphere or a reduced atmosphere at a temperature equal to or higher than a recombination temperature of the powder compact to form the rare-earth-iron-based alloy material. |
地址 |
Osaka JP |