WO2009125671A1 - Alliage à base r-t-b, procédé de production de l'alliage à base r-t-b, fines pour un aimant permanent à élément des terres rares en alliage à base r-t-b, aimant permanent à élément des terres rares en alliage à base r-t-b et procédé de production d'un aimant permanent à élément des terres rares en alliage à base r-t-b - Google Patents

Alliage à base r-t-b, procédé de production de l'alliage à base r-t-b, fines pour un aimant permanent à élément des terres rares en alliage à base r-t-b, aimant permanent à élément des terres rares en alliage à base r-t-b et procédé de production d'un aimant permanent à élément des terres rares en alliage à base r-t-b Download PDF

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WO2009125671A1
WO2009125671A1 PCT/JP2009/055939 JP2009055939W WO2009125671A1 WO 2009125671 A1 WO2009125671 A1 WO 2009125671A1 JP 2009055939 W JP2009055939 W JP 2009055939W WO 2009125671 A1 WO2009125671 A1 WO 2009125671A1
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rtb
alloy
mass
rare earth
earth permanent
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Japanese (ja)
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健一朗 中島
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昭和電工株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/058—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IVa elements, e.g. Gd2Fe14C
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/059—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—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
    • H01F41/02—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 for manufacturing cores, coils, or magnets
    • H01F41/0253—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 for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B22F2009/048—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by pulverising a quenched ribbon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C2202/00—Physical properties
    • C22C2202/02—Magnetic

Definitions

  • the present invention relates to an RTB-based alloy and a method for producing an RTB-based alloy, a fine powder for an RTB-based rare earth permanent magnet, an RTB-based rare earth permanent magnet, an RTB
  • the present invention relates to an RTB-based alloy capable of producing an RTB-based rare earth permanent magnet excellent in coercive force and a fine powder for an RTB-based rare earth permanent magnet. is there.
  • RTB-based magnets are used for HD (hard disk), MRI (magnetic resonance imaging), various motors and the like because of their high characteristics.
  • An RTB-based magnet is generically called an Nd-Fe-B-based magnet or an RTB-based magnet because its main components are Nd, Fe, and B.
  • R in the R—T—B system magnet is mainly obtained by substituting a part of Nd with other rare earth elements such as Pr, Dy, Tb, and T is a part of Fe other than Co, Ni, etc. Substituted with a transition metal.
  • B is boron, and a part thereof can be substituted with C or N.
  • An RTB-based alloy serving as an RTB-based magnet is composed of a main phase composed of a R 2 T 14 B phase, which is a magnetic phase that contributes to the magnetization action, and a non-magnetic, rare-earth element-concentrated low melting point.
  • the alloy ingot is pulverized to an average particle size of about 5 ⁇ m (d50: measured by a laser diffraction particle size distribution meter).
  • the R-rich phase plays an important role as follows. 1) The melting point is low and it becomes a liquid phase at the time of sintering, which contributes to increasing the density of the magnet and thus improving the magnetization. 2) Eliminate grain boundary irregularities, reduce reverse domain nucleation sites and increase coercivity. 3) The main phase is magnetically insulated to increase the coercive force. Therefore, if the dispersion state of the R-rich phase in the molded magnet is poor, local sintering failure and decrease in magnetism may occur. Therefore, it is important that the R-rich phase is uniformly dispersed in the molded magnet. Become. The distribution of the R-rich phase of the RTB-based sintered magnet is greatly influenced by the structure of the RTB-based alloy as a raw material.
  • ⁇ -Fe has deformability and remains in the pulverizer without being pulverized, so it not only lowers the pulverization efficiency when pulverizing the alloy, but also affects the composition variation and particle size distribution before and after pulverization. Effect. Furthermore, if ⁇ -Fe remains in the magnet after sintering, the magnetic properties of the magnet will be reduced. For this reason, conventional alloys have been subjected to homogenization treatment for a long time at a high temperature as necessary to eliminate ⁇ -Fe. However, since ⁇ -Fe exists as peritectic nuclei, long-term solid phase diffusion is required for its erasure. When the rare earth content is 33% or less in an ingot with a thickness of several centimeters, ⁇ -Fe is erased. Was virtually impossible.
  • SC method strip cast method for casting an alloy ingot at a higher cooling rate. It is practically used.
  • the SC method is a method in which the alloy is rapidly solidified by casting a thin piece of about 0.1 to 1 mm by pouring a molten metal onto a copper roll whose inside is water-cooled.
  • the molten metal is supercooled to a temperature below the formation temperature of the main phase R 2 T 14 B phase, it is possible to generate the R 2 T 14 B phase directly from the molten alloy, thereby suppressing the precipitation of ⁇ -Fe. can do.
  • the crystal structure of the alloy is refined by performing the SC method, an alloy having a structure in which the R-rich phase is finely dispersed can be generated.
  • the R-rich phase reacts with hydrogen in a hydrogen atmosphere and expands into a brittle hydride.
  • fine cracks are introduced in accordance with the degree of dispersion of the R-rich phase.
  • the alloy is broken by the large number of fine cracks generated by hydrogenation, so that the pulverizability becomes very good.
  • the alloy cast by the SC method has a fine dispersion of the R-rich phase inside, so the dispersibility of the R-rich phase in the magnet after pulverization and sintering is also good, and the magnetic properties of the magnet (See, for example, Patent Document 1).
  • the alloy flakes cast by the SC method are excellent in the homogeneity of the structure.
  • the homogeneity of the structure can be compared with the crystal grain size and the dispersion state of the R-rich phase.
  • chill crystals may occur on the casting roll side of the alloy flakes (hereinafter referred to as the “mold surface side”), but as a whole, it is moderately fine and homogeneous that is brought about by rapid solidification. Can get a good organization.
  • the RTB-based alloy cast by the SC method is excellent in producing a sintered magnet because the R-rich phase is finely dispersed and the production of ⁇ -Fe is suppressed. Has an organization.
  • the RTB-based alloy to which Dy is added is sintered using a two-alloy method to obtain the sintered magnet after sintering.
  • a method is known in which a large amount of Dy is present in the vicinity of the grain boundary of the RTB-based sintered magnet obtained.
  • the two-alloy method for example, an alloy having a low Dy concentration is prepared as a main phase RTB alloy, and an alloy having a high Dy concentration is prepared as a grain boundary phase RTB alloy.
  • a method in which two types of alloys, a phase system RTB alloy and a grain boundary phase system RTB alloy, are mixed and molded and sintered at a predetermined ratio.
  • the grain boundary phase of the rare earth permanent magnet obtained using this alloy is reduced.
  • Dy cannot be uniformly distributed, and variation becomes large, and a certain quality cannot be obtained.
  • the uniformity of the grain boundary phase of the obtained rare earth permanent magnet is lowered.
  • the Dy concentration must be lowered at the expense of the effect of improving the coercive force by increasing the Dy concentration in the RTB-based alloy.
  • the Dy concentration therein was in the range of 3% to 15% by mass.
  • the present invention has been made in view of the above circumstances, and has an excellent magnetic property in which the Dy concentration in the RTB-based alloy is high and the grindability of the RTB-based alloy is not reduced.
  • An object of the present invention is to provide an RTB-based alloy as a raw material for a rare earth-based permanent magnet having characteristics. Also, a method for producing the RTB-based alloy, fine powder for RTB-based rare earth permanent magnets and RTB-based rare earth permanent magnets prepared from the RTB-based alloy, RTB An object of the present invention is to provide a method for producing a TB-based rare earth permanent magnet.
  • the present inventors investigated the relationship between the RTB-based alloy used as a rare earth permanent magnet and the magnetic properties of the rare earth permanent magnet obtained using the alloy. Then, when producing a rare earth permanent magnet using an RTB-based alloy containing Dy, the present inventors used X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ as an RTB-based alloy. Even when the Dy concentration in the RTB-based alloy is increased, RT-T- is used by using a material having a diffraction peak at 31.1 to 31.3 ° and 37.8 to 38.0 °.
  • RTB system which is a raw material used for rare earth permanent magnets (where R is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, At least one of Er, Tm, Yb, and Lu, T is a transition metal containing 80 mass% or more of Fe, B contains 50 mass% or more of B, and 0 mass of at least one of C and N %) And less than 50% by mass.)
  • the R contains 20% by mass or more of Dy, and X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ shows diffraction peaks at 31.1 to 31.3 ° and 37.8 to 38.0 °.
  • the RTB-based alloy according to (1) which is a flake having an average thickness of 0.1 to 2 mm manufactured by a strip casting method.
  • the RTB-based alloy according to (1) which has an average thickness of 5 to 50 mm manufactured by a centrifugal casting method.
  • the RTB-based alloy according to (1) which has an average thickness of 10 to 50 mm manufactured by a book mold method.
  • a method for producing an RTB-based alloy according to any one of (1) to (4) A method for producing an RTB-based alloy comprising casting a molten alloy and solidifying it, followed by heat treatment at a temperature of 1,100 to 1,300 ° C. for 5 minutes to 120 hours.
  • the RTB system alloy produced by the method for producing the RTB system alloy according to any one of (1) to (4) or the RTB system alloy according to (5) A fine powder for RTB-based rare earth permanent magnets, characterized by being made from an alloy.
  • RTB-based alloy according to any one of (1) to (4) or the RTB-based alloy produced by the method for producing the RTB-based alloy according to (5)
  • An RTB system rare earth permanent comprising: a step of mixing an alloy with at least one other alloy for a rare earth permanent magnet; and a step of forming and sintering the mixed alloy. Magnet manufacturing method.
  • the R is 20% by mass to 80% by mass
  • the T is 20% by mass to 80% by mass
  • the B is 0% by mass to 1.5% by mass.
  • R contains 20% by mass or more of Dy
  • X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ shows diffraction peaks at 31.1 to 31.3 ° and 37.8 to 38.0 °. Therefore, it can be easily pulverized, a region having a high Dy concentration is formed uniformly in the grain boundary phase, and a rare earth permanent magnet having a high coercive force and excellent magnetic characteristics can be realized.
  • a molten alloy is cast and solidified, and then heat treatment is performed at a temperature of 1,100 to 1,300 ° C. for 5 minutes to 120 hours.
  • the R is 20% by mass to 80% by mass
  • the T is 20% by mass to 80% by mass
  • the B is 0% by mass to 1.5% by mass
  • the R is 20% by mass or more.
  • the RTB-based alloy of the present invention in which diffraction peaks appear at 31.1 to 31.3 ° and 37.8 to 38.0 ° by X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ is obtained.
  • FIG. 1 is a photograph showing an example of an RTB-based alloy of the present invention, and a backscattered electron image when a cross section of a thin piece of the RTB-based alloy is observed with a scanning electron microscope (SEM). It is.
  • FIG. 2 is a schematic front view showing a configuration of an alloy manufacturing apparatus according to an embodiment of the present invention.
  • FIG. 3 is an X-ray diffraction diagram of fine powder for RTB-based rare earth permanent magnets.
  • FIG. 4 is a diagram showing the Dy concentration contained in the powder left in the pulverizer after the fine powder for RTB system rare earth permanent magnets was produced.
  • FIG. 1 is a photograph showing an example of an RTB-based alloy of the present invention, and a backscattered electron image when a cross section of a thin piece of the RTB-based alloy is observed with a scanning electron microscope (SEM). It is.
  • the left side is the mold surface side.
  • the RTB-based alloy shown in FIG. 1 is a raw material used for a rare earth-based permanent magnet, and is manufactured by the SC method.
  • a white part is a part (R rich layer) where the concentration of rare earth elements is higher than the surroundings, and a black part is a part (phase) containing a lot of iron.
  • R is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. It is at least one kind, T is a transition metal containing 80 mass% or more of Fe, B contains 50 mass% or more of B, and at least one of C and N contains 0 mass% or more and less than 50 mass%. Further, the RTB-based alloy shown in FIG. 1 has an R of 20% by mass to 80% by mass, T of 20% by mass to 80% by mass, and B of 0% by mass to 1.5% by mass. It is included in the range.
  • the RTB-based alloy shown in FIG. 1 includes Dy containing R of 20% by mass or more.
  • Dy containing R of 20% by mass or more.
  • the Dy concentration contained in the RTB-based alloy is higher, the rare earth permanent magnet obtained after sintering is more likely to concentrate in the grain boundary phase, and a rare earth permanent magnet having a higher coercive force is more likely to be obtained.
  • the Dy contained in the RTB-based alloy is less than 20% by mass, the coercive force of a rare earth permanent magnet produced using this may not be improved effectively.
  • the RTB-based alloy shown in FIG. 1 has characteristic diffraction peaks of 31.1 to 31.3 ° and 37.8 to 38.0 ° in X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ . It is what appears.
  • diffraction peaks appear at 31.1 to 31.3 ° and 37.8 to 38.0 ° in X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ . Therefore, even if the RTB-based alloy contains 20% by mass or more of Dy, excellent grindability can be obtained. Therefore, the fine powder for rare earth permanent magnets made of the fine powder of the RTB system alloy can be easily prepared using the RTB system alloy shown in FIG. 1, and the obtained fine powder for the rare earth permanent magnet can be used. By producing a rare earth permanent magnet, it is possible to produce a rare earth permanent magnet in which a region having a high Dy concentration is uniformly formed in the grain boundary phase.
  • an RTB-based alloy is cast.
  • the casting apparatus shown in FIG. 2 casts molten alloy by the SC method.
  • reference numeral 1 is a crucible for supplying molten alloy to the dundish 2
  • reference numeral 2 is a dundish for supplying molten alloy to the cooling roll 3
  • reference numeral 3 represents the molten alloy.
  • Reference numeral 4 denotes a container for accommodating the cast alloy flakes 5 cast by the cooling roll 3.
  • the molten alloy is prepared in a high-frequency melting furnace (not shown).
  • the temperature of the molten alloy is adjusted in the range of 1,300 ° C. to 1,500 ° C., although it depends on the alloy components.
  • the prepared molten alloy is supplied from the crucible 1 to the cooling roll 3 through the tundish 2 as shown in FIG.
  • the supply speed of the molten alloy and the number of rotations of the cooling roll 3 are controlled according to the thickness of the cast alloy.
  • the number of rotations of the cooling roll 3 is, for example, about 0.5 to 3 m / s in terms of peripheral speed.
  • the cast alloy flakes 5 solidified on the cooling roll 3 are separated from the cooling roll 3 on the opposite side of the tundish 2.
  • the separated cast alloy flakes 5 are dropped and supplied to the container 4.
  • the average thickness of the cast alloy flakes 5 thus obtained is preferably in the range of 0.1 to 2 mm.
  • the average thickness is in the range of 0.1 to 2 mm, a fine alloy structure can be obtained, so that excellent grindability can be exhibited.
  • the RTB-based alloy cast alloy flake 5 thus obtained is heat-treated at a temperature of 1,100 to 1,300 ° C. for 5 minutes to 120 hours.
  • the heat treatment can be performed by a method of holding at a temperature of 1,100 to 1,300 ° C. for 5 minutes to 120 hours when the molten alloy is cooled immediately after casting and solidifying.
  • the heat treatment is a method in which the molten alloy is immediately cooled to 200 ° C. or less immediately after the molten alloy is solidified, again heated to a temperature of 1,100 to 1,300 ° C. in a heating furnace, and held for 5 minutes to 120 hours. May be performed.
  • the cast alloy flakes 5 subjected to heat treatment are mixed at a predetermined ratio with another at least one rare earth permanent magnet cast alloy flakes obtained by different components and / or different production methods, and mixed flakes. Is done.
  • hydrogen cracking is performed by allowing the mixed flakes to store hydrogen at room temperature.
  • the cast alloy flakes 5 can be easily pulverized by hydrogen crushing the cast alloy flakes 5 subjected to the heat treatment.
  • the RTB-based rare earth permanent magnet fine powder thus obtained is press-molded using, for example, a transverse magnetic field molding machine and baked at 1,050 to 1,100 ° C. in a vacuum. By bonding, an RTB-based rare earth permanent magnet can be obtained.
  • R is 20% by mass to 80% by mass
  • T is 20% by mass to 80% by mass
  • B is 0% by mass to 1.5% by mass.
  • R contains Dy of 20% by mass or more and X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ shows diffraction peaks at 31.1 to 31.3 ° and 37.8 to 38.0 °
  • a region having a high Dy concentration is formed uniformly in the grain boundary phase, and a rare earth permanent magnet having a high coercive force and excellent magnetic characteristics can be realized.
  • the RTB-based alloy of this embodiment has diffraction peaks at 31.1 to 31.3 ° and 37.8 to 38.0 ° in X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ . Therefore, even if R contains 20% by mass or more of Dy, excellent grindability can be obtained. Therefore, by using the RTB-based alloy of the present embodiment, it is possible to easily create a fine powder for a rare-earth permanent magnet composed of the fine powder of the RTB-based alloy of the present embodiment. By producing a rare earth permanent magnet using fine powder for magnets, a rare earth permanent magnet in which a region having a high Dy concentration is uniformly formed in the grain boundary phase can be produced. The rare earth permanent magnets thus obtained have a constant quality and excellent magnetic properties with high coercive force because composition fluctuations are suppressed.
  • the molten alloy is cast and solidified, and then heat treatment is performed at a temperature of 1,100 to 1,300 ° C. for 5 minutes to 120 hours.
  • R contains 20% by mass or more of Dy
  • X-ray diffraction (2 ⁇ / ⁇ ) by CuK ⁇ shows unique diffraction peaks at 31.1 to 31.3 ° and 37.8 to 38.0 °.
  • the method for producing a rare earth permanent magnet of the present embodiment includes a step of mixing the RTB-based alloy of the present embodiment with at least one other alloy for a rare earth permanent magnet, and the mixed alloy.
  • the magnetic properties such as coercive force are further improved by appropriately changing the characteristics and mixing ratio of another rare earth permanent magnet alloy to be mixed. be able to.
  • the RTB-based alloy according to the present invention is manufactured using the SC method. It is not limited.
  • a molten alloy may be cast using a centrifugal casting method, a book mold method, or the like as a method for producing an RTB-based alloy.
  • the centrifugal casting method for example, it is preferable to manufacture one having an average thickness of 5 to 50 mm.
  • the average thickness is in the range of 5 to 50 mm, the structure is larger than that produced by the SC method, but a predetermined pulverization characteristic can be exhibited by the subsequent heat treatment.
  • the book mold method it is preferable to manufacture a product having an average thickness of 10 to 50 mm. When the average thickness is in the range of 10 to 50 mm, predetermined grinding characteristics can be exhibited by heat treatment.
  • the cast alloy flakes which are the RTB-based alloy of the present invention and another cast alloy for at least one rare earth permanent magnet obtained by different components and / or different production methods are used.
  • the flakes were mixed at a predetermined ratio to obtain mixed flakes, and the mixed flakes were finely pulverized into fine powders for rare earth permanent magnets.
  • the present invention is not limited to this example.
  • the mixing of the RTB-based alloy of the present invention with at least one other rare earth permanent magnet alloy can be performed in the state of a cast alloy flake, as shown in the above example.
  • the RTB-based alloy of the present invention can be used alone as a raw material for rare earth permanent magnet fine powder or rare earth permanent magnet without being mixed with another rare earth permanent magnet alloy.
  • Example Weighed the raw materials blended so as to be Dy 35%, B 0.0%, Al 0.5%, Cu 10% and the balance Fe by mass ratio, using an alumina crucible, and in a high pressure atmosphere of argon gas at 1 atm.
  • An alloy melt was prepared by melting in a melting furnace. Next, this molten alloy was supplied to the casting apparatus shown in FIG. 2 and cast by the SC method. The peripheral speed of the cooling roll 3 at the time of casting was 1.0 m / s.
  • the average thickness of the cast alloy flakes 5 of the obtained RTB-based alloy was 0.3 mm.
  • the cast alloy flakes 5 thus obtained were heat-treated in argon at a temperature of 1,200 ° C. for 12 hours using a heating furnace to obtain a cast alloy flake A1 of the example.
  • FIG. 3 shows an X-ray diffraction pattern of the powder of the cast alloy flake A1 of the example thus obtained. Note that the powder X-ray diffraction (2 ⁇ / ⁇ ) measurement shown in FIG. 3 was performed with CuK ⁇ rays at a scanning speed of 2 ° / sec. As shown by arrows in FIG. 3, in the examples, characteristic diffraction peaks appeared at diffraction angles of 31.2 and 37.9 °.
  • a cast alloy flake M was produced as another alloy for a rare earth permanent magnet. That is, the raw materials blended so that the mass ratio is Nd 32%, B 1.0%, Al 0.2%, and the balance Fe are weighed, and the cast alloy flake M is produced under the same conditions as when the cast alloy flake A is produced. did.
  • the cast alloy flake A1 and the cast alloy flake M are mixed at a mass ratio of 5:95, subjected to a hydrogen storage treatment in hydrogen at 2 atm at room temperature, and then heated to 500 ° C. in a vacuum to remain. Hydrogen was extracted, 0.07% by mass of zinc stearate was added, and finely pulverized using a jet mill in a nitrogen stream.
  • the average particle size of the alloy powder of the example obtained after fine pulverization (fine powder for RTB rare earth permanent magnet) by laser diffraction measurement was 5.0 ⁇ m.
  • “Comparative example” A cast alloy flake A2 of a comparative example was obtained in the same manner as the production method of the cast alloy flake A1 in Example 1 except that the heat treatment was not performed.
  • X-ray diffraction measurement was performed in the same manner as the powder of the cast alloy flake A1 of Example 1. The result is shown in FIG. As shown in FIG. 3, in the comparative example, the specific diffraction peaks at the diffraction angles of 31.2 and 37.9 ° appearing in the example were not observed.
  • a cast alloy flake M similar to that of the example is used, and the cast alloy flake A2 of the comparative example and the cast alloy flake M are mixed at the same ratio as in the example.
  • the average particle size of the alloy powder of the comparative example (RTB-based rare earth permanent magnet fine powder) obtained after pulverization was 5.0 ⁇ m as measured by laser diffraction.
  • a powder of 10 to 30 minutes from the start of pulverization was formed in a 100% nitrogen atmosphere using a molding machine in a transverse magnetic field, and a molding pressure of 0.8 t / cm 2.
  • the product was obtained by press molding.
  • the obtained molded body was heated from room temperature in a vacuum of 1.33 ⁇ 10 ⁇ 5 hPa and kept at 500 ° C. and 800 ° C. for one hour to remove zinc stearate and residual hydrogen.

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Abstract

La présente invention se rapporte à un alliage à base R-T-B qui est une matière première brute pour un aimant permanent à élément des terres rares. Dans l'alliage à base R-T-B, R représente au moins un élément parmi le scandium (Sc), l'yttrium (Y), le lanthane (La), le cérium (Ce), le praséodyme (Pr), le néodyme (Nd), le prométhium (Pm), le samarium (Sm), l'europium (Eu), le gadolinium (Gd), le terbium (Tb), le dysprosium (Dy), l'holmium (Ho), l'erbium (Er), le thulium (Tm), l'ytterbium (Yb) et le lutétium (Lu), T représente un métal de transition contenant au moins de 80 % en masse de fer (Fe) et B contient au moins de 50 % en masse de bore (B) et contient au moins de 0% en masse et moins de 50 % en masse de carbone (C) et/ou d'azote (N). L'alliage à base R-T-B est caractérisé en ce que les teneurs en R, T et B ne sont pas inférieures à 20 % en masse et pas supérieures à 80 % en masse, pas inférieures à 20 % en masse et pas supérieures à 80 % en masse, et pas inférieures à 0 % en masse et pas supérieures à 1,5 % en masse, respectivement, en ce que R contient au moins de 20 % en masse de Dy et des pics de diffraction apparaissent entre 31,1 et 31,3 °C et entre 37,8 et 38,0 °C comme mesuré par la diffractométrie de rayons X (2θ/θ) utilisant CuKα.
PCT/JP2009/055939 2008-04-10 2009-03-25 Alliage à base r-t-b, procédé de production de l'alliage à base r-t-b, fines pour un aimant permanent à élément des terres rares en alliage à base r-t-b, aimant permanent à élément des terres rares en alliage à base r-t-b et procédé de production d'un aimant permanent à élément des terres rares en alliage à base r-t-b WO2009125671A1 (fr)

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EP2623235A4 (fr) * 2010-09-30 2015-06-24 Showa Denko Kk Matériau d'alliage pour aimant permanent aux terres rares du système r-t-b, procédé de production d'un aimant permanent aux terres rares du système r-t-b et moteur électrique

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CN105161282B (zh) * 2015-10-08 2017-12-05 北京华太鑫鼎金属材料有限公司 钕铁硼磁体的烧结方法

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JPH09137259A (ja) * 1995-11-09 1997-05-27 Hitachi Metals Ltd 希土類リッチ相形成用合金およびその粉砕方法ならびに希土類永久磁石の製造方法
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JP4753030B2 (ja) * 2006-04-14 2011-08-17 信越化学工業株式会社 希土類永久磁石材料の製造方法

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JPH07122413A (ja) * 1993-10-28 1995-05-12 Hitachi Metals Ltd 希土類永久磁石およびその製造方法
JPH09137259A (ja) * 1995-11-09 1997-05-27 Hitachi Metals Ltd 希土類リッチ相形成用合金およびその粉砕方法ならびに希土類永久磁石の製造方法
JP2005036302A (ja) * 2002-10-25 2005-02-10 Showa Denko Kk 希土類含有合金の製造方法、希土類含有合金、希土類含有合金粉末の製造方法、希土類含有合金粉末、希土類含有合金焼結体の製造方法、希土類含有合金焼結体、磁歪素子、及び磁気冷凍作業物質
JP2005286175A (ja) * 2004-03-30 2005-10-13 Tdk Corp Ｒ−ｔ−ｂ系焼結磁石及びその製造方法
WO2006098204A1 (fr) * 2005-03-14 2006-09-21 Tdk Corporation Aimant fritte a base de r-t-b
JP2006274344A (ja) * 2005-03-29 2006-10-12 Tdk Corp Ｒ−ｔ−ｂ系焼結磁石の製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2623235A4 (fr) * 2010-09-30 2015-06-24 Showa Denko Kk Matériau d'alliage pour aimant permanent aux terres rares du système r-t-b, procédé de production d'un aimant permanent aux terres rares du système r-t-b et moteur électrique

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