# US 2013/0252004 A1 · Rare earth-iron-nitrogen-based alloy material, method for producing rare earth-iron-nitrogen-based alloy material, rare earth-iron-based alloy material, and method for producing rare earth-iron-based alloy material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0252004 A1 - Document ID: US20130252004A1 - Status: Published application - Kind: A1 - Application number: 13/824,553 - Filed: 2012-05-22 - Published: 2013-09-26 - Earliest claimed: 2011-05-24 - Assignees: Sumitomo Electric Industries, Ltd. - Inventors: Toru Maeda; Asako Watanabe; Motoi Nagasawa; Takeshi Kato - Web page: https://patentgrep.com/patent/US20130252004A1 ## CPC - B22F 3/087: using high energy impulses, e.g. magnetic field impulses - B22F 1/00: Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties - B22F 3/1017: {Multiple heating or additional steps (B22F3/101 takes precedence)} - C22C 38/001: {containing N} - C22C 38/005: {containing rare earths, i.e. Sc, Y, Lanthanides} - C22C 38/04: containing manganese - C22C 38/14: containing titanium or zirconium - H01F 1/053: containing rare earth metals - H01F 1/059: and Va elements, e.g. Sm2Fe17N2 - H01F 41/0246: {Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36)} - H01F 41/0266: {Moulding; Pressing (H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11)} - B22F 2998/10: Processes characterised by the sequence of their steps - B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy - H01F 1/0573: {obtained by reduction or by hydrogen decrepitation or embrittlement} - Y10T 428/31678: Of metal - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - C22C: ALLOYS (treatment of alloys C21D, C22F) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention provides a rare earth-iron-nitrogen-based alloy material which can produce a rare earth magnet having excellent magnetic characteristics and a method for producing the same, a rare earth-iron-based alloy material suitable as a raw material of the rare earth magnet and a method for producing the alloy material. A rare earth-iron-based alloy material is heat-treated in a hydrogen-containing atmosphere to produce a multi-phase powder 1 in which a phase 3 of a hydrogen compound of a rare earth element is dispersedly present in a phase 2 of an iron-containing material. A powder compact 4 produced by compression-molding the multi-phase powder 1 is heat-treated in a vacuum with a magnetic field of 3 T or more applied, thereby forming a rare earth-iron-based alloy material 5. The rare earth-iron-based alloy material 5 is heat-treated in a nitrogen atmosphere with a magnetic field of 3.5 T or more applied, thereby forming a rare earth-iron-nitrogen-based alloy material 6. The rare earth-iron-based alloy material 5 has a structure in which a crystal of a rare earth-iron-based alloy is oriented in the c-axis direction. The rare earth-iron-nitrogen-based alloy material 6 composed of an ideal nitride can be formed by nitriding the rare earth-iron-based alloy material 5 having this oriented structure with the magnetic field applied, and a rare earth magnet 7 having excellent magnetic characteristics can be formed. ## Claims ### Claim at position 1 -10. (canceled) ### Claim 11 A rare earth-iron-based alloy material used for a raw material of a rare earth magnet, the alloy material comprising a compact composed of a plurality of alloy particles which are composed of a rare earth-iron-based alloy containing a rare earth element, wherein I(a, b, c)/Imax≧0.83 is satisfied, where when any desired plane constituting the outer surface of the compact or any desired section of the compact is used as a measurement plane, Imax is a maximum X-ray diffraction peak intensity at the measurement plane, I(a, b, c) is an X-ray diffraction peak intensity along an axis of a crystal lattice constituting the alloy particles present in the measurement plane, and I(a, b, c)/Imax is a ratio of the peak intensity along the axis to the maximum peak intensity. ### Claim 12 A rare earth-iron-nitrogen-based alloy material used for a raw material of a rare earth magnet, the alloy material comprising a compact composed of a plurality of alloy particles which are composed of a rare earth-iron-nitrogen-based alloy containing a rare earth element, wherein I(a, b, c)/Imax≧0.83 is satisfied, where when any desired plane constituting the outer surface of the compact or any desired section of the compact is used as a measurement plane, Imax is a maximum X-ray diffraction peak intensity at the measurement plane, I(a, b, c) is an X-ray diffraction peak intensity along an axis of a crystal lattice constituting the alloy particles present in the measurement plane, and I(a, b, c)/Imax is a ratio of the peak intensity along the axis to the maximum peak intensity. ### Claim 13 (depends on 12) The rare earth-iron-nitrogen-based alloy material according to claim 12, wherein Ic/Imax≧0.83 is satisfied, where Ic is an X-ray diffraction peak intensity along a c-axis of the crystal lattice. ### Claim 14 (depends on 12) The rare earth-iron-nitrogen-based alloy material according to claim 12, wherein the rare earth element is Sm. ### Claim 15 (depends on 12) The rare earth-iron-nitrogen-based alloy material according to claim 12, wherein the alloy contains Sm and Ti. ### Claim 16 A method for producing a rare earth-iron-based alloy material used for a raw material of a rare earth magnet, the method comprising: a preparation step of heat-treating a rare earth-iron-based alloy powder containing a rare earth element in an atmosphere containing a hydrogen element at a temperature equal to or higher than a disproportionation temperature of the rare earth-iron-based alloy to prepare a multi-phase powder composed of a multi-phase particle in which a phase of a hydrogen compound of the rare earth element is dispersedly present in a phase of an iron-containing material containing Fe, and the content of the phase of the hydrogen compound of the rare earth element is 40% by volume or less; a molding step of forming a powder compact by compression-molding the multi-phase powder; and a dehydrogenation step of heat-treating the powder compact in an inert atmosphere or a reduced-pressure atmosphere at a temperature equal to or higher than a recombination temperature of the powder compact to form a rare earth-iron-based alloy material, wherein the heat treatment in the dehydrogenation step is performed by applying a magnetic field of 3 T or more to the powder compact. ### Claim 17 (depends on 16) The method for producing a rare earth-iron-based alloy material according to claim 16, wherein the magnetic field is applied using a high-temperature superconducting magnet. ### Claim 18 A method for producing a rare earth-iron-nitrogen-based alloy material used for a raw material of a rare earth magnet, the method comprising: a preparation step of heat-treating a rare earth-iron-based alloy powder containing a rare earth element in an atmosphere containing a hydrogen element at a temperature equal to or higher than a disproportionation temperature of the rare earth-iron-based alloy to prepare a multi-phase powder composed of a multi-phase particle in which a phase of a hydrogen compound of the rare earth element is dispersedly present in a phase of an iron-containing material containing Fe, and the content of the phase of the hydrogen compound of the rare earth element is 40% by volume or less; a molding step of forming a powder compact by compression-molding the multi-phase powder; a dehydrogenation step of heat-treating the powder compact in an inert atmosphere or a reduced-pressure atmosphere at a temperature equal to or higher than a recombination temperature of the powder compact to form a rare earth-iron-based alloy material; and a nitriding step of heat-treating the rare earth-iron-based alloy material in an atmosphere containing a nitrogen element at a temperature equal to or higher than a nitriding temperature and equal to or lower than a nitrogen disproportionation temperature of the rare earth-iron-based alloy material to form a rare earth-iron-nitrogen-based alloy material, wherein the heat treatment in the dehydrogenation step is performed by applying a magnetic field of 3 T or more to the powder compact; and the heat treatment in the nitriding step is performed by applying a magnetic field of 3.5 T or more to the rare earth-iron-based alloy material. ### Claim 19 (depends on 18) The method for producing a rare earth-iron-nitrogen-based alloy material according to claim 18, wherein a direction in which the magnetic field is applied in the nitriding step is the same as a direction in which the magnetic field is applied in the dehydrogenation step. ### Claim 20 (depends on 18) The method for producing a rare earth-iron-nitrogen-based alloy material according to claim 18, wherein in the dehydrogenation step and the nitriding step, the magnetic field is applied using a high-temperature superconducting magnet.