# US 9,520,230 B2 · Production method of rare earth magnet > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,230 B2 - Document ID: US9520230B2 - Status: Granted - Kind: B2 - Application number: 13/824,572 - Filed: 2011-05-13 - Published: 2013-09-26 - Granted: 2016-12-13 - Earliest claimed: 2010-10-25 - Assignees: Toyota Jidosha Kabushiki Kaisha; Centre National De La Recherche Scientifique; Leibniz Institute for Solid State and Materials Research Dresden; The University of Sheffield - Applicants: Noritsugu Sakuma; Hidefumi Kishimoto; Akira Kato; Tetsuya Shoji; Dominique Givord; Nora Dempsey; Thomas George Woodcock; Oliver Gutfleisch; Gino Hrkac; Thomas Schrefl - Inventors: Noritsugu Sakuma; Hidefumi Kishimoto; Akira Kato; Tetsuya Shoji; Dominique Givord; Nora Dempsey; Thomas George Woodcock; Oliver Gutfleisch; Gino Hrkac; Thomas Schrefl - Web page: https://patentgrep.com/patent/US9520230B2 ## CPC - H01F 41/0273: {Imparting anisotropy (methods and devices for magnetising permanent magnets H01F13/003)} - C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60} - C22C 38/005: {containing rare earths, i.e. Sc, Y, Lanthanides} - C22C 38/06: containing aluminium - C22C 38/16: containing copper - H01F 1/01: of inorganic materials (H01F1/44 takes precedence) - H01F 41/00: Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties - H01F 41/005: {Impregnating or encapsulating (insulating of windings H01F41/12)} - H01F 41/32: for applying conductive, insulating or magnetic material on a magnetic film {, specially adapted for a thin magnetic film} - B22F 2003/248: {Thermal after-treatment} - B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy - B22F 2998/10: Processes characterised by the sequence of their steps - B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy - C22C 2202/02: Magnetic - H01F 1/0576: {pressed, e.g. hot working} - H01F 1/0577: {sintered} - H01F 10/126: {containing rare earth metals (H01F10/133 takes precedence)} - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - C22C: ALLOYS (treatment of alloys C21D, C22F) - 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 ## Abstract A rare earth magnet, which is represented by a neodymium magnet (Nd2Fe14B) and neodymium magnet films with applications in micro-systems. A method for producing a rare earth magnet, comprising: (a) quenching a molten metal having a rare earth magnet composition to form quenched flakes of nanocrystalline structure; sintering the quenched flakes; subjecting the sintered body obtained to an orientation treatment; and applying a heat treatment with pressurization at a temperature sufficiently high to enable diffusion or fluidization of a grain boundary phase and at the same time, low enough to prevent coarsening of the crystal grains, (b) thick films deposited on a substrate, applying an annealing to crystallize with pressurization at a temperature sufficiently high to enable diffusion or fluidization of a grain boundary phase and, at the same time, low enough to prevent coarsening of the crystal grains. ## Claims ### Claim 1 The method for producing a rare earth magnet, comprising: quenching a molten metal having a rare earth magnet composition to form quenched flakes having nanocrystalline structure, sintering said quenched flakes, subjecting the sintered body obtained to an orientation treatment, and then applying a heat treatment with pressurization to the orientation-treated sintered body at a temperature sufficiently high to enable diffusion or fluidization of a grain boundary phase and, at the same time, low enough to prevent coarsening of the crystal grains; wherein rare earth magnet being in the form of a bulk. ### Claim 2 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein the pressure applied during said heat treatment is 1 to 300 MPa. ### Claim 3 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein the heat treatment is performed for 1 minute to 5 hours. ### Claim 4 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein the temperature of said heat treatment is a temperature that is higher than the melting point or eutectic temperature of the grain boundary phase and, at the same time, gives a crystal grain size of 300 nm or less after the heat treatment. ### Claim 5 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein the temperature of said heat treatment is 450 to 700° C. ### Claim 6 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein an element capable of lowering the temperature at which said grain boundary phase can be diffused or fluidized is added to said rare earth magnet composition. ### Claim 7 (depends on 6) The method for producing a rare earth magnet according to claim 6, wherein said element is an element capable of lowering the melting point or eutectic temperature of the grain boundary phase down to a melting temperature lower than that of Nd. ### Claim 8 (depends on 7) The method for producing a rare earth magnet according to claim 7, wherein said element is selected from Al, Cu, Mg, Fe, Co, Ag, Ni and Zn. ### Claim 9 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein said rare earth magnet composition is represented by the following compositional formula; and an element capable of alloying with Fe, and thereby lowering the temperature at which the grain boundary phase can be diffused or fluidized, is added to said rare earth magnet composition in an amount sufficiently large to lower said temperature and small enough to cause no deterioration of magnetic characteristics and hot workability: R1vFewCoxByM1z R1: one or more kinds of rare earth elements including Y, M1: at least one of Ga, Zn, Si, Al, Nb, Zr, Ni, Cu, Cr, Hf, Mo, P, C, Mg and V, 13≦v≦20, w=100−v−x−y−z, 0≦x≦30, 4≦y≦20, 0≦z≦3. ### Claim 10 (depends on 9) The method for producing a rare earth magnet according to claim 9, wherein, in said compositional formula R1vFewCoxByM1z, the amount v of R1 (one or more kinds of rare earth elements including Y) is 13≦v≦17, and the amount y of B is 5≦y≦16. ### Claim 11 (depends on 9) The method for producing a rare earth magnet according to claim 9, wherein the main phase of the rare earth magnet is Nd2Fe14B, and an element capable of alloying with Nd of the grain boundary phase and thereby lowering the temperature at which the grain boundary phase can be diffused or fluidized, is added in an amount sufficiently large to lower said temperature and small enough to cause no deterioration of magnetic characteristics and hot workability. ### Claim 12 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein said rare earth magnet composition is represented by the following compositional formula, and composed of a main phase ((R2R3)2(FeCo)14B) and grain boundary phases ((R2R3)(FeCo)4B4 phase and R2R3 phase); and an element capable of alloying with R and thereby lowering the temperature at which the grain boundary phase can be diffused or fluidized, is added to said rare earth magnet composition in an amount sufficiently large to lower said temperature and small enough to cause no deterioration of magnetic characteristics and hot workability: R2aR3bFecCodBeM2f R2: one or more kinds of rare earth elements, excluding Dy and Tb and including Y, R3: one or more kinds of heavy rare earth elements consisting of Dy and Tb, M2: at least one of Ga, Zn, Si, Al, Nb, Zr, Ni, Cu, Cr, Hf, Mo, P, C, Mg, Hg, Ag and Au, 13≦a≦20, 0≦b≦4, c=100−a−b−d−e−f, 0≦d≦30, 4≦e≦20, 0≦f≦3. ### Claim 13 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein said orientation treatment is a hot working. ### Claim 14 (depends on 1) The method for producing a rare earth magnet according to claim 1, wherein Ga is added to said rare earth magnet composition.