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WO2019078148A1 - Matériau d'aimant à base de terres rares et aimant à base de terres rares - Google Patents

Matériau d'aimant à base de terres rares et aimant à base de terres rares Download PDF

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WO2019078148A1
WO2019078148A1 PCT/JP2018/038290 JP2018038290W WO2019078148A1 WO 2019078148 A1 WO2019078148 A1 WO 2019078148A1 JP 2018038290 W JP2018038290 W JP 2018038290W WO 2019078148 A1 WO2019078148 A1 WO 2019078148A1
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rare earth
less
earth magnet
powder
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一誠 嶋内
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Sumitomo Electric Industries Ltd
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Sumitomo Electric Industries Ltd
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    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/07—Alloys based on nickel or cobalt based on cobalt
    • 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
    • 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
    • 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
    • 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

Definitions

  • the present disclosure relates to rare earth magnet materials and rare earth magnets.
  • This application claims the priority based on Japanese Patent Application No. 2017-201590 filed on Oct. 18, 2017, and incorporates all the contents described in the aforementioned Japanese Patent Application.
  • Patent Document 1 discloses a rare earth magnet using a powder of an Nd-Fe-B based alloy (for example, Nd 2 Fe 14 B) containing Nd (neodymium), Fe (iron) and B (boron).
  • Nd-Fe-B based alloy for example, Nd 2 Fe 14 B
  • Nd neodymium
  • Fe iron
  • B boron
  • a hydrogenated powder obtained by hydrogenating a powder of an Nd-Fe-B alloy is used as a raw material powder, and a powder compact obtained by compression molding the raw material powder is subjected to a dehydrogenation treatment to obtain an Nd-Fe-B alloy
  • the material is manufactured and this alloy material is used for the material of the rare earth magnet.
  • the rare earth magnet material according to the present disclosure is Composition of at least one rare earth element R containing Nd, at least one transition metal element T containing Fe, and at least one element X selected from B and C, and the composition ratio of R is ⁇ , T A first phase containing a compound represented by R ⁇ T ⁇ X, where the ratio is ⁇ ; A grain boundary phase which is present at grain boundaries of the first phase and has a concentration of R higher than that of the R ⁇ T ⁇ X; When it is composed of at least one rare earth element S containing Sm and at least one transition metal element M containing Co, and the composition ratio of S is ⁇ , and the composition ratio of M is ⁇ , it is represented by S ⁇ M ⁇ And a second phase containing the compound.
  • the rare earth magnet material according to the present disclosure is Composition of at least one rare earth element R containing Nd, at least one transition metal element T containing Fe, and at least one element X selected from B and C, and the composition ratio of R is ⁇ , T A first phase containing a compound represented by R ⁇ T ⁇ X, where the ratio is ⁇ ; A grain boundary phase which is present at grain boundaries of the first phase and has a concentration of R higher than that of the R ⁇ T ⁇ X; When it is composed of at least one rare earth element S containing Sm and at least one transition metal element M containing Co, and the composition ratio of S is ⁇ , and the composition ratio of M is ⁇ , it is represented by S ⁇ M ⁇ And a second phase containing the compound.
  • FIG. 1 is a schematic view showing the structure of a rare earth magnet material according to the embodiment.
  • FIG. 2A is a first diagram for explaining a manufacturing process of the rare earth magnet material according to the embodiment.
  • FIG. 2: B is a 2nd figure explaining the manufacturing process of the rare earth magnet raw material which concerns on embodiment.
  • FIG. 2C is a third diagram illustrating the manufacturing process of the rare earth magnet material according to the embodiment.
  • FIG. 2D is a fourth diagram illustrating the manufacturing process of the rare earth magnet material according to the embodiment.
  • FIG. 3 is a schematic view showing the structure of the rare earth magnet according to the embodiment.
  • the residual magnetic flux density and coercivity of the rare earth magnet change with temperature.
  • the degree (temperature coefficient) in which the characteristics of residual magnetic flux density and coercivity change with temperature is large, and the residual magnetic flux density and coercivity decrease significantly as the temperature increases. easy.
  • a rare earth magnet material is: Composition of at least one rare earth element R containing Nd, at least one transition metal element T containing Fe, and at least one element X selected from B and C, and the composition ratio of R is ⁇ , T A first phase containing a compound represented by R ⁇ T ⁇ X, where the ratio is ⁇ ; A grain boundary phase which is present at grain boundaries of the first phase and has a concentration of R higher than that of the R ⁇ T ⁇ X; When it is composed of at least one rare earth element S containing Sm and at least one transition metal element M containing Co, and the composition ratio of S is ⁇ , and the composition ratio of M is ⁇ , it is represented by S ⁇ M ⁇ And a second phase containing the compound.
  • the rare earth magnet material can reduce the degree (temperature coefficient) of change in magnetic characteristics due to temperature as compared to the case where the second phase is not provided, and is sufficient even under high temperatures.
  • a rare earth magnet having magnetic properties is obtained.
  • the rare earth magnet material can reduce the degree of change in residual magnetic flux density with temperature (temperature coefficient of residual magnetic flux density) and the degree of change in coercive force with temperature ( The temperature coefficient (coefficient of coercivity) can be reduced, and reduction in residual magnetic flux density and coercivity can be suppressed at high temperatures.
  • the content of the second phase in the rare earth magnet material may be 3% by mass or more and 50% by mass or less.
  • the content of the second phase in the rare earth magnet material is 3% by mass or more, a rare earth magnet having magnetic properties sufficient for practical use even at high temperatures can be obtained.
  • the content of the second phase in the rare earth magnet material is 50% by mass or less, the content of the first phase in the rare earth magnet material can be secured, and a decrease in residual magnetic flux density can be suppressed. And the increase in cost can be suppressed.
  • composition ratio of S ⁇ M ⁇ satisfies the above range, it is easy to obtain a rare earth magnet having excellent magnetic properties.
  • the above-mentioned rare earth magnet material it is mentioned that the above-mentioned R alpha T beta X is 1.5 or more and 2.5 or less, and beta is 12.5 or more and 15.5 or less.
  • composition ratio of R ⁇ T ⁇ X satisfies the above range, it is easy to obtain a rare earth magnet having excellent magnetic properties.
  • the R ⁇ T ⁇ X is Nd 2 T 14 X.
  • the average grain size of the said 1st phase is 700 nm or less.
  • the average grain size of the first phase is 700 nm or less, the effect of improving the magnetic properties (in particular, the coercivity) attributed to the fine crystal structure can be expected.
  • the rare earth magnet material according to the embodiment of the present disclosure is Composition of at least one rare earth element R containing Nd, at least one transition metal element T containing Fe, and at least one element X selected from B and C, and the composition ratio of R is ⁇ , T A first phase containing a compound represented by R ⁇ T ⁇ X, where the ratio is ⁇ ; A grain boundary phase which is present at grain boundaries of the first phase and has a concentration of R higher than that of the R ⁇ T ⁇ X; When it is composed of at least one rare earth element S containing Sm and at least one transition metal element M containing Co, and the composition ratio of S is ⁇ , and the composition ratio of M is ⁇ , it is represented by S ⁇ M ⁇ And a second phase containing the compound, In the S ⁇ M ⁇ , ⁇ is 1 or more and 3 or less, ⁇ is 4 or more and 18 or less, In the above R ⁇ T ⁇ X, ⁇ is 1.5 or more and 2.5 or less, and ⁇ is 1
  • a rare earth magnet Composition of at least one rare earth element R containing Nd, at least one transition metal element T containing Fe, and at least one element X selected from B and C, and the composition ratio of R is ⁇ , T
  • a grain boundary phase which is present at grain boundaries of the first phase and has a concentration of R higher than that of the R ⁇ T ⁇ X;
  • it is composed of at least one rare earth element S containing Sm and at least one transition metal element M containing Co, and the composition ratio of S is ⁇ , and the composition ratio of M is ⁇ , it is represented by S ⁇ M ⁇
  • a second phase containing the compound When it is composed of at least one rare earth element S containing Sm and at least one transition metal element M containing Co, and the composition ratio of S is ⁇ , and the composition ratio of M is ⁇ , it is represented by S ⁇ M ⁇ And a second phase containing the compound.
  • the above-described rare earth magnet can reduce the degree of change in magnetic characteristics (temperature coefficient) due to temperature as compared with the case where the second phase is not provided, and is sufficient even under high temperatures. Magnetic properties are obtained. Specifically, by providing the second phase, the rare earth magnet can reduce the degree of change in residual magnetic flux density with temperature (temperature coefficient of residual magnetic flux density), and the degree of change in coercive force with temperature The temperature coefficient of the magnetic force can be reduced, and reduction in residual magnetic flux density and coercivity at high temperatures can be suppressed.
  • the content of the second phase in the rare earth magnet is, for example, 3% by mass or more and 50% by mass or less.
  • the content of the second phase in the rare earth magnet is 3% by mass or more, practically sufficient magnetic characteristics can be obtained even under high temperature.
  • the content of the second phase in the rare earth magnet material is 50% by mass or less, the content of the first phase in the rare earth magnet can be secured, and a decrease in residual magnetic flux density can be suppressed. Cost increase can be suppressed.
  • the S ⁇ M ⁇ may have ⁇ of 1 or more and 3 or less, and ⁇ of 4 or more and 18 or less.
  • composition ratio of S ⁇ M ⁇ satisfies the above range, excellent magnetic properties can be obtained.
  • the R ⁇ T ⁇ X preferably has ⁇ of 1.5 or more and 2.5 or less and ⁇ of 12.5 or more and 15.5 or less.
  • composition ratio of R ⁇ T ⁇ X satisfies the above range, excellent magnetic properties can be obtained.
  • the average crystal grain size of the first phase may be 700 nm or less.
  • the average grain size of the first phase is 700 nm or less, the effect of improving the magnetic properties (in particular, the coercivity) attributed to the fine crystal structure can be expected.
  • the rare earth magnet material 1 is R ⁇ T ⁇ X (R is at least one rare earth element containing Nd, T is at least one transition metal element containing Fe, X is at least one element selected from B and C, ⁇ Is the composition ratio of R, ⁇ is the composition ratio of T) and is present at the grain boundaries of the crystal grains 110 constituting the first phase 11 containing the compound and is more than R ⁇ T ⁇ X And an intergranular phase 111 with a high concentration of R.
  • a rare earth magnet using a rare earth magnet material containing Nd tends to lower the residual magnetic flux density and the coercivity as the temperature rises.
  • the rare earth magnet material 1 according to the embodiment has a configuration capable of exhibiting sufficient residual magnetic flux density and coercive force even under high temperature.
  • the rare earth magnet material 1 according to the embodiment is S ⁇ M ⁇ (S is at least one rare earth element including Sm, M is at least one transition metal element including Co, ⁇ is a composition ratio of S,
  • the second phase 12 containing a compound represented by the composition ratio of M) is provided.
  • the first phase 11 contains a compound represented by R ⁇ T ⁇ X.
  • the first phase 11 is polycrystalline.
  • one grain of the first phase 11 is shown as one square, and one crystal grain 110 that constitutes the polycrystal of the first phase 11 is shown as one hexagon.
  • R is at least one rare earth element including Nd (neodymium).
  • R may be Nd alone, or a part of Nd is at least one element selected from Pr (praseodymium), Ce (cerium), Dy (dysprosium), Tb (terbium) and Y (yttrium) It may be substituted.
  • the content of R in R ⁇ T ⁇ X is, for example, 25% by mass or more and 35% by mass or less, and further 26% by mass or more and 34% by mass or less.
  • the content of the substituting element occupying in the entire R may be 3% by mass or less, and further 2% by mass or less.
  • T is at least one transition metal element including Fe (iron).
  • T may be Fe alone, or part of Fe may be Co (cobalt), Ni (nickel), Ga (gallium), Cu (copper), Al (aluminum), Si (silicon), Ti (titanium) And at least one element selected from Mn (manganese) and Nb (niobium).
  • the content of T in R ⁇ T ⁇ X is, for example, 62% by mass or more and 74.5% by mass or less, and further 64% by mass or more and 73% by mass or less.
  • the content of the substitution element occupying in the entire T may be 10% by mass or less, and further 8% by mass or less.
  • X is at least one element selected from B (boron) and C (carbon). X may be B or C alone, or a part of B may be substituted with C.
  • the content of X in R ⁇ T ⁇ X is, for example, 0.7% by mass or more and 1.5% by mass or less, and further, 0.8% by mass or more and 1.3% by mass or less.
  • the content of C in the entire X is 0.1% by mass or less, and further preferably 0.07% by mass or less.
  • the stoichiometric composition of R ⁇ T ⁇ X is 1.5 to 2.5, ⁇ is 12.5 to 15.5, ⁇ is 1.6 to 2.4, and ⁇ is 13. It is preferable to satisfy 0 or more and 15.0 or less.
  • the stoichiometric composition of R ⁇ T ⁇ X is ideally R 2 T 14 X.
  • the stoichiometric composition of R ⁇ T ⁇ X includes Nd 2 Fe 14 B, Nd 2 Fe 14 C, Nd 2 (Fe 13 Co 1 ) B, and the like. By satisfying this composition, the magnetic properties can be enhanced.
  • This composition is determined from the content of each element in the first phase. The content of the element can be measured by ICP (Inductively Coupled Plasma) emission spectroscopy.
  • the average grain size of the crystal grains 110 constituting the polycrystal of the first phase 11 may be 700 nm or less.
  • the average crystal grain size is as small as 700 nm or less, the effect of improving the magnetic properties (in particular, the coercivity) attributed to the fine crystal structure can be expected.
  • the smaller the average crystal grain size the better the magnetic properties, and may be 500 nm or less, further 300 nm or less.
  • the average crystal grain size is observed on the surface or cross section of the rare earth magnet material 1 with a scanning electron microscope (SEM), the area of each crystal grain 110 is examined from the observation image, and the equal area of each area is obtained. It can be obtained by measuring the equivalent circle diameter and calculating its average value. When calculating using an observation image, it can be easily calculated using commercially available image processing software.
  • the grain boundary phase 111 is present at the grain boundaries of the crystal grains 110 constituting the first phase 11.
  • the grain boundary phase 111 is formed by the extra R that does not form the stoichiometry of R ⁇ T ⁇ X in the first phase 11.
  • the grain boundary phase 111 has a higher concentration (mass% concentration) of R than R ⁇ T ⁇ X, for example, 1.1 times or more, and further 1.2 times the concentration of R in R ⁇ T ⁇ X Meet the above.
  • the crystal grains 110 constituting the first phase 11 are connected by the grain boundary phase 111.
  • Second phase 12 comprises a compound represented by S ⁇ M ⁇ .
  • the second phase 12 is a single crystal.
  • one particle of the second phase 12 is shown as one circle.
  • the gap between the first phase 11 and the second phase 12 is exaggerated in FIG. 1, the gap is actually small or substantially absent.
  • S is at least one rare earth element including Sm (samarium).
  • S may be Sm alone, or part of Sm may be substituted with at least one element selected from Pr, Ce, Dy, Tb and Y.
  • the content of S in S ⁇ M ⁇ is, for example, 30% by mass or more and 38% by mass or less, and further 32% by mass or more and 36% by mass or less.
  • the content of the substitution element occupying in the whole of S is 5% by mass or less, and further 3% by mass or less.
  • M is at least one transition metal element including Co (cobalt).
  • M may be Co alone, or part of Co may be substituted by at least one element selected from Fe, Ni, Ga, Cu, Al, Si, Ti, Mn and Nb.
  • the content of M in S ⁇ M ⁇ is, for example, 62% by mass or more and 70% by mass or less, and further 64% by mass or more and 68% by mass or less.
  • the content of the substituting element occupying in the entire M may be 30% by mass or less, and further 20% by mass or less.
  • the stoichiometric composition of S ⁇ M ⁇ it is preferable that ⁇ be 1 or more and 3 or less and ⁇ be 4 or more and 18 or less.
  • the stoichiometric composition of S ⁇ M ⁇ includes Sm 1 Co 5 , Sm 2 Co 17 and the like. By satisfying this composition, the magnetic properties can be enhanced.
  • This composition is determined from the content of each element in the second phase. The content of the element can be measured by ICP emission spectrometry.
  • the rare earth magnet material 1 can reduce the degree of change in magnetic characteristics (temperature coefficient) due to temperature compared to the case where the second phase 12 is not provided, and the magnetic characteristics are high at high temperatures. It is possible to suppress the decrease.
  • the content of the second phase 12 in the rare earth magnet material 1 may be 3% by mass or more and 50% by mass or less. When the content of the second phase 12 is 3% by mass or more, practically sufficient magnetic characteristics can be exhibited even under high temperature. As the content of the second phase 12 increases, the temperature coefficient of the rare earth magnet material 1 can be reduced, and the content is further 5% by mass or more, 10% by mass or more, particularly 15% by mass or more, 20% by mass or more, 25% by mass or more Being mentioned.
  • the content of the second phase 12 increases, the content of the first phase 11 in the rare earth magnet material 1 relatively decreases, and the residual magnetic flux density decreases, and the cost increases. 50% by mass or less, further 45% by mass or less, 40% by mass or less, particularly 35% by mass or less.
  • the respective contents of the first phase 11 and the second phase 12 in the rare earth magnet material 1 are the same as the respective contents of the first phase powder 31 and the second phase powder 32 of the raw material powder in the method of manufacturing the rare earth magnet material 1 described later. It is.
  • the degree of change in residual magnetic flux density with temperature is less than 0.129% / ° C. in absolute value
  • the degree of change in coercivity with temperature is less than 0.562% /. Degree. C. in absolute value. Since the temperature coefficient of residual magnetic flux density is less than 0.129% / ° C. in absolute value and the temperature coefficient of coercivity is less than 0.562% / ° C. in absolute value, the magnet can be used even in a large temperature change environment The performance becomes constant, and changes in device performance due to temperature changes can be reduced.
  • the temperature coefficient of the residual magnetic flux density and the temperature coefficient of the coercivity have negative values, and the smaller the absolute value, the smaller the temperature change of the residual magnetic flux density and the coercivity.
  • the temperature coefficient of the residual magnetic flux density in the rare earth magnet material 1 is such that the temperature change of the residual magnetic flux density is smaller as the absolute value is smaller, so the absolute value is 0.127% / ° C. or less, and 0.120% / ° C as an absolute value. It is mentioned that it is the following. Further, the temperature coefficient of the coercivity in the rare earth magnet material 1 has a smaller change in temperature of the coercivity as the absolute value decreases, so the absolute value is 0.541% / ° C. or less, and the absolute value is 0.492% / ° C It is mentioned that it is the following.
  • the temperature coefficient of the residual magnetic flux density and the temperature coefficient of the coercivity can be reduced as the content of the second phase 12 increases, but the content of the second phase 12 has a preferable range. Therefore, the temperature coefficient of residual magnetic flux density is 0.078% / ° C. or more in absolute value, and the temperature coefficient of coercivity is 0.283% / ° C. or more in absolute value. The method of measuring the temperature coefficient of the residual magnetic flux density and the temperature coefficient of the coercivity will be described in the test examples described later.
  • the rare earth magnet material 1 described above can be suitably used as a material for permanent magnets, for example, permanent magnets used for various types of motors, in particular, high-speed motors provided in hybrid vehicles and hard disk drives.
  • the rare earth magnet material 1 described above can be manufactured, for example, by performing a preparation process, a molding process, and a dehydrogenation process. A method of manufacturing the rare earth magnet material 1 will be described with reference to FIGS. 2A to 2D.
  • magnet powder 3 in which first phase powder 31 and second phase powder 32 are mixed is prepared.
  • the preparation step includes the steps of preparing the first phase powder 31, preparing the second phase powder 32, and mixing the first phase powder 31 and the second phase powder 32.
  • Preparation process of first phase powder In the preparation step of the first phase powder 31, a powder of RTX based alloy having a compound represented by R ⁇ T ⁇ X (for example, Nd 2 T 14 X) as a main phase is prepared, and the powder of this alloy is prepared. Is subjected to hydrogenation treatment. That is, the first phase powder 31 obtained after the hydrotreating is a hydrogenated powder of an RTX based alloy. Further, in the step of preparing the first phase powder 31, the hydrogenated powder after the hydrotreating is crushed.
  • R ⁇ T ⁇ X for example, Nd 2 T 14 X
  • the powder of the RTX-based alloy is obtained, for example, by crushing a molten cast ingot made of the RTX-based alloy or a foil-like body obtained by a rapid solidification method with a grinding apparatus such as a jaw crusher, jet mill or ball mill. Or, it can be manufactured using an atomizing method such as a gas atomizing method.
  • the size of the powder of this RTX-based alloy is, for example, 500 ⁇ m or more and 30 mm or less in maximum diameter. When the maximum diameter is 500 ⁇ m or more, it is easy to grind to a medium particle size at the time of the subsequent grinding, and it is easy to produce a hydrogenated powder of a particle size suitable for compression molding. On the other hand, when the maximum diameter is 30 mm or less, the time required for the subsequent grinding can be shortened.
  • the maximum diameter refers to the length of the longest part of the particle of one RTX-based alloy when viewed in plan from all directions.
  • the atmosphere containing a hydrogen element may be a single atmosphere of only H 2 (hydrogen) or a mixed atmosphere of H 2 and an inert gas such as Ar (argon) or N 2 (nitrogen).
  • the temperature during heat treatment is set to a temperature at which the disproportionation reaction of the RTX based alloy proceeds, ie, the disproportionation temperature or more.
  • the disproportionation reaction is a reaction that separates into a hydrogen compound of a rare earth element and iron (or iron and an iron compound) by preferential hydrogenation of the rare earth element (at least one rare earth element R containing Nd).
  • the lower limit temperature at which the reaction occurs is called disproportionation temperature.
  • the disproportionation temperature varies depending on the composition of the R-T-X-based alloy and the type of the rare earth element R, but may be, for example, 600 ° C. or more and 1100 ° C. or less.
  • the RTX-based alloy is Nd 2 Fe 14 B, 650 ° C. or higher can be mentioned.
  • the holding time at the time of heat treatment may be 0.5 hours to 5 hours. This heat treatment can apply known disproportionation conditions.
  • Each of the first phase particles 310 constituting the hydrogenated powder (first phase powder 31) obtained by the above-mentioned hydrotreating has a structure in which phase decomposition into a phase 311 of a hydrogen compound of rare earth element and a phase 312 of iron-containing material (See FIG. 2A).
  • the hydrogen compound of the rare earth element includes RH 2 and the like.
  • iron-containing substances include Fe and Fe 2 X.
  • the first phase particles 310 after this hydrotreating have the presence of pure iron which is a soft portion softer than the phase 311 of the R-T-X based alloy before the phase decomposition or the hydrogen compound of the rare earth element. When compression molding is carried out in a molding step to be described later, it is easily deformed to improve the moldability.
  • the existence mode of the phase 311 of the hydrogen compound of the rare earth element and the phase 312 of the iron-containing material is a layered form in which the phase 311 of the hydrogen compound of the rare earth element and the phase 312 of the iron-containing material have a laminated structure
  • the form of their existence depends on the heat treatment conditions (mainly temperature) of the hydrotreating.
  • the dispersed form is easier to improve formability than the layered form because the iron-containing phase 312 uniformly exists around the phase 311 of the rare earth element hydrogen compound. Therefore, it is easy to obtain powder compacts (rare earth magnet material 1) of various shapes such as arc shape, cylindrical shape, and cylindrical shape. In addition, it is easy to obtain a high density powder compact with high magnetic powder density.
  • the phase 312 of the iron-containing material is preferably 60% by volume or more.
  • the phase 311 of the hard compound of the rare earth element is relatively reduced, and the formability is easily improved at the time of compression molding in a molding process described later.
  • the phase 312 of the iron-containing material is 90% by volume or less, the phase 311 of the hydrogen compound of the rare earth element is relatively large, and the magnetic characteristics are excellent.
  • the iron-containing phase 312 further includes 63% by volume or more and 85% by volume or less and 65% by volume or more and 80% by volume or less.
  • the phase 311 of the hydrogen compound of the rare earth element and the phase 312 of the iron-containing material are adjacent to each other, and the distance between the phase 311 of the hydrogen compound of the rare earth element adjacent through the iron-containing phase 312 is 3 ⁇ m or less Being mentioned.
  • the structure in which the iron containing phase 312 is present between the rare earth element hydrogen compound phases 311 and the rare earth element hydrogen compound phase 311 is present at a specific interval is a structure in which both phases 311 and 312 are uniformly present. Therefore, when compression molding is carried out, it deforms uniformly.
  • the phase 311 of the hydrogen compound of the rare earth element and the phase 312 of the iron-containing substance recombine with the RTX based alloy before the phase decomposition by dehydrogenation later. Further, it is possible to suppress the deterioration of the magnetic properties due to the coarsening of the crystal grains of the R-T-X-based alloy as well as to avoid the need to input excessive energy.
  • the iron-containing phase 312 may be sufficiently present between the rare earth element hydrogen compound phases 311, the above-mentioned interval may be 0.5 ⁇ m or more, and further 1 ⁇ m or more.
  • the above-mentioned interval can be controlled, for example, by adjusting the composition of the RTX-based alloy used as the raw material, or by adjusting the conditions of the hydrotreating, in particular, the heat treatment temperature. For example, when the ratio (atomic ratio) of iron is increased in the RTX-based alloy or the heat treatment temperature is increased in the above-described temperature range, the above-mentioned interval tends to be increased.
  • the cross section of the first phase particle 310 is etched to remove the iron-containing phase 312 to extract the rare earth element hydrogen compound phase 311 or rare earth depending on the type of etching solution.
  • the phase 311 of the hydrogen compound of the element is removed to extract the phase 312 of the iron-containing substance, or the cross section can be measured by composition analysis using an EDX (energy dispersive X-ray analyzer).
  • the hydrogenated powder (first phase powder 31) after the hydrotreating can be pulverized and controlled to a desired particle size.
  • the hydrotreated powder is pulverized to a medium particle size to produce a first phase powder 31 having a particle size suitable for compression molding.
  • the respective first phase particles 310 constituting the first phase powder 31 have substantially the same structure (phase 311 of hydrogen compound of rare earth element and phase 312 of iron-containing material) before and after grinding.
  • the first phase powder 31 obtained by grinding preferably has an average particle diameter D50 of 50 ⁇ m or more and 700 ⁇ m or less.
  • Such a first phase powder 31 is particularly excellent in moldability because it has a particle diameter suitable for compression molding in a molding step to be described later.
  • the average particle diameter D50 is 50 ⁇ m or more
  • the particles constituting the second phase powder 32 can be easily firmly bonded to each other.
  • the average particle diameter D50 of the first phase powder 31 is further 75 ⁇ m or more and 550 ⁇ m or less, in particular 100 ⁇ m or more and 400 ⁇ m or less.
  • the average particle diameter D50 is a particle diameter that takes a volume-based particle size distribution when measured by a laser diffraction type particle size distribution measuring device, and the accumulation becomes 50% from the small diameter side It is the value. This point is the same as in the second phase powder 32 described later.
  • a powder of an SM based alloy having a compound represented by S ⁇ M ⁇ (for example, Sm 1 Co 5 ) as a main phase is prepared.
  • the powder of this SM type alloy is manufactured, for example, by high frequency melting the raw material of the SM type alloy in an inert gas atmosphere such as Ar, and thereafter pulverizing it with a pulverizer such as a jaw crusher or a jet mill. can do.
  • the size of the powder of the SM type alloy (second phase powder 32) preferably has an average particle diameter D50 (50 volume% particle diameter) of 1 ⁇ m or more and 1000 ⁇ m or less.
  • the average particle diameter D50 of the second phase powder 32 is further 3 ⁇ m or more and 900 ⁇ m or less, in particular 5 ⁇ m or more and 800 ⁇ m or less.
  • the mixing ratio of the first phase powder 31 and the second phase powder 32 in the powder 3 for magnet is maintained at the existing ratio (content) of the first phase 11 and the second phase 12 in the obtained rare earth magnet material 1 . Therefore, the temperature coefficient of the rare earth magnet material 1 can be reduced as the proportion of the second phase powder 32 in the powder 3 for magnet increases.
  • the blending ratio of the second phase powder 32 in the powder 3 for magnet is 3% or more, further 5% or more, 10% or more, particularly 15% or more, 20% or more, 25% or more in mass ratio Be
  • the compounding ratio of the second phase powder 32 in the powder 3 for magnet is too large, the compounding ratio of the first phase powder 31 in the powder 3 for magnet relatively decreases, and the formability is lowered or obtained.
  • the residual magnetic flux density of the rare earth magnet material 1 may be reduced or the cost may be increased. Therefore, the compounding ratio of the second phase powder 32 in the powder 3 for magnet may be 50% or less, 45% or less, 40% or less, particularly 35% or less by mass ratio.
  • the mixing of the first phase powder 31 and the second phase powder 32 may be performed using a suitable mixer capable of uniformly mixing the two powders 31 and 32.
  • the mixing time is, for example, 10 minutes or more and 3 hours or less, and further 30 minutes or more and 2.5 hours or less.
  • the mixing may be carried out in a nitrogen atmosphere.
  • powder 3 for magnet is compression-molded to produce powder compact 2.
  • a mold 9 capable of obtaining a powder compact 2 having a desired shape.
  • the mold 9 typically forms a molding space with a die 91 having a through hole and the inner peripheral surface of the die 91, and is inserted into the through hole to form a pair of upper punches for compression molding of the magnet powder 3. And 92 and a lower punch 93.
  • a rod (not shown) inserted and disposed in the through hole of the die 91 is used.
  • the molding pressure can be appropriately selected to achieve the desired relative density.
  • the molding pressure is, for example, 490 MPa or more and 1,500 MPa or less.
  • the atmosphere at the time of the dehydrogenation treatment is a non-hydrogen atmosphere so that each hydrogen can be efficiently removed without reacting with the hydrogenated powder (first phase powder 31).
  • the non-hydrogen atmosphere includes an inert atmosphere or a reduced pressure atmosphere, for example, an inert gas atmosphere such as Ar or N 2 , or a vacuum atmosphere having a pressure lower than the standard atmospheric pressure.
  • an inert gas atmosphere such as Ar or N 2
  • a vacuum atmosphere having a pressure lower than the standard atmospheric pressure for example, an inert gas atmosphere such as Ar or N 2
  • a vacuum atmosphere having a pressure lower than the standard atmospheric pressure.
  • the temperature of the heat treatment at the time of the dehydrogenation treatment is at least the recombination temperature of the powder compact 2 (the temperature at which the separated iron-containing material and the rare earth element combine).
  • the recombination temperature varies depending on the composition of the particles constituting the powder compact 2, for example, the temperature is preferably 600 ° C. to 1000 ° C., more preferably 650 ° C. to 850 ° C., and still more preferably 700 ° C. to 800 ° C.
  • Be The heat treatment time at the time of the dehydrogenation treatment may be, for example, 10 minutes to 10 hours, more preferably 30 minutes to 5 hours, and further 1 hour to 3 hours.
  • the relative density of the rare earth magnet material 1 obtained by the dehydrogenation treatment is substantially equal to the relative density of the powder compact 2 although it changes somewhat depending on the temperature and time of the heat treatment.
  • the rare earth magnet material 1 is recombined with the original compound represented by R ⁇ T ⁇ X, with the phase 311 of the hydrogen compound of the rare earth element and the phase 312 of the iron-containing substance phase-decomposed by hydrogenation. And a polycrystalline structure in which the crystal grains are refined. It is mentioned that this average crystal grain size is 700 nm or less. Referring to FIG.
  • the rare earth magnet material 1 after the dehydrogenation treatment is R ⁇ T ⁇ X
  • R is at least one rare earth element including Nd
  • T is at least one transition metal element including Fe
  • X is B and at least one element selected from C
  • alpha is the composition ratio of R
  • beta is the first phase 11 containing a compound represented by T composition ratio of
  • S ⁇ M ⁇ S is at least one that contains the Sm
  • the second phase 12 includes a rare earth element
  • M is at least one transition metal element including Co
  • ⁇ is a composition ratio of S
  • ⁇ is a composition ratio of M).
  • a powder for a magnet was prepared by mixing the first phase powder and the second phase powder.
  • a cast flake having a stoichiometry of Nd 2 Fe 14 B and a size of 0.5 to 30 mm is prepared as a first phase powder, and the cast flake is subjected to a hydrogenation treatment and then crushed to obtain a hydrogenated powder.
  • the hydrogenation treatment was performed at 850 ° C. for 3 hours in a hydrogen atmosphere.
  • the grinding was performed using a cemented carbide mortar.
  • the pulverized hydrogenated powder (first phase powder) had an average particle diameter D50 of 150 ⁇ m.
  • a powder having an average particle diameter D50 of 10 ⁇ m and a stoichiometric composition of Sm 1 Co 5 was prepared.
  • the prepared first phase powder and the second phase powder were mixed to prepare a powder for a magnet.
  • the mixing was performed for 30 minutes in a nitrogen atmosphere using a V-type mixer.
  • the blend ratio of the first phase powder to the second phase powder is shown in Table 1.
  • Sample No. 1-11 used only the first phase powder as a powder for a magnet.
  • the above-mentioned powder for a magnet was filled in a mold and compression molded to prepare a powder compact having a diameter of 10 mm and a height of 10 mm. Compression molding was performed at a molding pressure of 980 MPa (10 ton / cm 2 ).
  • the powder compact was dehydrogenated to prepare a sample of a rare earth magnet material.
  • the dehydrogenation treatment was performed at 800 ° C. for 3 hours in a vacuum atmosphere (vacuum degree: less than 0.5 Pa).
  • the average crystal grain size of the crystal grains constituting the first phase was measured from the observation image of the SEM. Specifically, the area of each crystal grain is examined from the observation image using commercially available image processing software, and the average equivalent circular diameter of each area is taken as the average crystal grain size. As a result, it was found that the average crystal grain size was 700 nm or less.
  • the rare earth magnet material of each sample is magnetized with a pulse magnetic field of 3.5 T to prepare a rare earth magnet of each sample, and the temperature coefficient (% / ° C.) of residual magnetic flux density and temperature coefficient (%) of coercivity in the rare earth magnet / ° C) was examined.
  • the temperature coefficient of the residual magnetic flux density and the temperature coefficient of the coercivity are such that the inside of the glove box installed in the BH tracer (BHH-530AP made by Riken Denshi) is made into a nitrogen atmosphere, and the rare earth magnet material of each sample is made in the glove box.
  • BH tracer BHH-530AP made by Riken Denshi
  • the rare earth magnet 10 is R ⁇ T ⁇ X (R is at least one rare earth element including Nd, T is at least one transition metal element including Fe, and X is B and at least one element selected from C, alpha is the composition ratio of R, beta is the first phase 11 containing a compound represented by T composition ratio of), S ⁇ M ⁇ (S is at least one that contains the Sm
  • the second phase 12 includes a rare earth element, M is at least one transition metal element including Co, ⁇ is a composition ratio of S, and ⁇ is a composition ratio of M).
  • sample No. 2 containing 3% by mass or more of the second phase powder.
  • 1-1 to 1-5 show sample No. 1 which does not contain the second phase powder. It can be seen that the absolute values of the temperature coefficient of residual magnetic flux density and the temperature coefficient of coercivity are smaller than those in 1-11. Specifically, sample No. 3 containing 3% by mass of the second phase powder. Sample No. 1-1 does not contain the second phase powder. Compared to 1-11, the temperature coefficient of residual magnetic flux density is about 1.5% smaller, and the temperature coefficient of coercivity is about 3.7% smaller. The temperature coefficient of residual magnetic flux density is reduced by about 1.5%, and the temperature coefficient of coercivity is reduced by about 3.7%, so that the rare earth magnet material has sufficient magnetic properties for practical use even at high temperatures. Can be expected to
  • the content of the second phase powder is preferably 50% by mass or less.

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Abstract

L'invention concerne un matériau d'aimant à base de terres rares comprenant : une première phase comprenant un composé constitué d'au moins un type d'élément des terres rares R comprenant du Nd, d'au moins un type d'élément de métal de transition T comprenant du Fe, et d'au moins un type d'élément X choisi entre du B et du C, le composé étant représenté par RαTβX, où α est le rapport de composition de R et β est le rapport de composition de T ; une phase de frontière de grains présente dans une frontière de cristaux de la première phase et ayant une concentration en R supérieure à celle de RαTβ ; et une seconde phase comprenant un composé constitué d'au moins un type d'élément des terres rares S comprenant du Sm et d'au moins un type d'élément de métal de transition M comprenant du Co, le composé étant représenté par SγMδ, γ étant le rapport de composition de S, et δ étant le rapport de composition de M.
PCT/JP2018/038290 2017-10-18 2018-10-15 Matériau d'aimant à base de terres rares et aimant à base de terres rares Ceased WO2019078148A1 (fr)

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DE112021008057T5 (de) 2021-08-04 2024-07-11 Mitsubishi Electric Corporation Seltenerd-sintermagnet, verfahren zum produzieren eines seltenerd-sintermagneten, rotor und rotationsmaschine

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10163015A (ja) * 1996-12-03 1998-06-19 Seiko Epson Corp 磁石合金粉末とその製造方法およびそれを用いた磁石
JP2003124012A (ja) * 2001-10-12 2003-04-25 Hitachi Ltd 複合磁石、複合磁性材料、および、モータ
JP2011129768A (ja) * 2009-12-18 2011-06-30 Toyota Motor Corp 希土類磁石およびその製造方法
JP2015135855A (ja) * 2014-01-16 2015-07-27 住友電気工業株式会社 希土類磁石、及び希土類磁石の製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10163015A (ja) * 1996-12-03 1998-06-19 Seiko Epson Corp 磁石合金粉末とその製造方法およびそれを用いた磁石
JP2003124012A (ja) * 2001-10-12 2003-04-25 Hitachi Ltd 複合磁石、複合磁性材料、および、モータ
JP2011129768A (ja) * 2009-12-18 2011-06-30 Toyota Motor Corp 希土類磁石およびその製造方法
JP2015135855A (ja) * 2014-01-16 2015-07-27 住友電気工業株式会社 希土類磁石、及び希土類磁石の製造方法

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