Magnetic materials and permanent magnets

Abstract

To enhance intrinsic coercivity and remanent magnetization of a magnetic material.SOLUTION: A magnetic material is represented by the composition formula 1: RxNbyBzM100-x-y-z (R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x represents a number satisfying 4≤x≤10 atomic %, y represents a number satisfying 0.1≤y≤8 atomic %, and z represents a number satisfying 0.1≤z≤12 atomic %), and further contains at least one element selected from the group consisting of nitrogen, carbon, hydrogen, and phosphorus, and has a main phase having a TbCu7 type crystal phase and a grain boundary phase. When the average Nb concentration in the TbCu7 type crystal phase is represented as nNb1 and the maximum Nb concentration in the grain boundary phase is represented as nNb2, the relationship of nNb2 / nNb1>5 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The embodiments relate to magnetic materials and permanent magnets. [Background technology]

[0002] Permanent magnets are used in a wide range of products, including rotating electrical machines such as motors and generators, electrical equipment such as speakers and measuring instruments, and vehicles such as automobiles and railway cars. In recent years, there has been a demand for the above products to be more compact, more efficient, and more powerful, and this has created a demand for high-performance permanent magnets with high magnetization and high coercive force.

[0003] Examples of high-performance permanent magnets include rare-earth magnets such as Sm-Co magnets and Nd-Fe-B magnets. In these magnets, Fe and Co contribute to increasing the saturation magnetization. These magnets also contain rare-earth elements such as Nd and Sm, which result in large magnetic anisotropy due to the behavior of the 4f electrons of the rare-earth elements in the crystalline field. This allows for large coercive forces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4320701 [Patent Document 2] Japanese Patent Application Publication No. 2020-155774 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to increase the coercive force and remanence of a magnetic material. [Means for solving the problem]

[0006] The magnetic material of the embodiment has the composition formula 1: x Nb y B z M 100-x-y-z(R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x is a number satisfying 4≦x≦10 atomic %, y is a number satisfying 0.1≦y≦8 atomic %, and z is a number satisfying 0.1≦z≦12 atomic %), and further contains at least one element selected from the group consisting of nitrogen, carbon, hydrogen, and phosphorus, and comprises a main phase having a TbCu7 type crystal phase and a grain boundary phase. The average Nb concentration in the TbCu7 type crystal phase is defined as n Nb1 and the maximum Nb concentration in the grain boundary phase is expressed as n Nb2 When expressed as Nb2 / n Nb1 >5. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an example of the structure of a metal structure. [Figure 2] 1 is a diagram showing the results of three-dimensional atom probe analysis (concentration distribution of Nb and B) in Example 1. FIG. [Figure 3] FIG. 10 is a diagram showing the results of three-dimensional atom probe analysis (concentration distribution of Nb and B) in Comparative Example 1. [Figure 4] FIG. 2 is a diagram showing the concentration distribution of each element in the grain boundary phase of Example 1. [Figure 5] FIG. 1 is a diagram showing the concentration distribution of each element in the grain boundary phase of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0008] The magnet material of the embodiment contains a rare earth element, an M element (M is at least one element selected from the group consisting of Fe and Co), niobium (Nb), and boron (B). The magnet material has a metal structure with a TbCu7-type crystalline phase as the main phase, which contains a high concentration of the M element. Increasing the concentration of the M element in the main phase can improve saturation magnetization, thereby improving remanence. The magnet material may be substantially composed of a TbCu7-type crystalline phase as the main phase and a grain boundary phase, but may also contain other phases such as a microcrystalline phase or an impurity phase. The main phase is the phase with the highest volumetric occupancy among the crystalline phases and amorphous phases in the magnet material. Figure 1 is a schematic diagram showing an example of the structure of a metal structure. Figure 1 shows crystal grains 101 having a TbCu7-type crystalline phase and grain boundaries 102, which are located between the multiple crystal grains 101 and have a grain boundary phase.

[0009] Adding Nb and B to rare earth elements and M elements enhances the ability to form amorphous structures, resulting in uniform main phase crystal grain size after heat treatment, thereby increasing remanence and coercivity. The above-mentioned magnetic materials are available in powder or ribbon form, which are molded to produce permanent magnets. Examples of permanent magnets include bonded magnets molded using a binder such as resin, and sintered magnets manufactured by sintering powder. Permanent magnets are used in rotating electrical machines such as motors and generators. In recent years, there has been an increasing demand for smaller, faster, and more efficient motors and generators, which has led to a corresponding increase in the demand for improved heat resistance of permanent magnets. To achieve this, it is necessary to improve the coercivity of permanent magnets and magnetic materials.

[0010] One effective method for achieving high coercivity in magnetic materials with large magnetic anisotropy is to refine the crystal grains of the magnetic material, for example, by producing an amorphous ribbon using a liquid quenching method and then subjecting it to an appropriate heat treatment to precipitate and grow crystal grains.

[0011] By miniaturizing the main phase, which has high magnetic anisotropy, individual crystal grains are more likely to become single-domain particles, suppressing the generation of reverse magnetic domains and domain wall propagation, thereby achieving high coercivity. Because coercivity decreases when the crystal grain size is too small or too large, the average crystal grain size of the main phase is preferably 1 nm or more and 1000 nm or less (1 μm), more preferably 1 nm or more and 100 nm or less, and even more preferably 10 nm or more and 80 nm or less. Furthermore, narrowing the particle size distribution of the main phase improves the squareness in the demagnetization characteristics of the magnetic material, thereby improving the maximum energy product.

[0012] Another effective method for improving coercivity is to form grain boundary phases between crystal grains to weaken the magnetic coupling between them. Weakening the magnetism of the grain boundary phase, or ideally making it non-magnetic, increases the effectiveness of suppressing the generation and propagation of reverse magnetic domains, thereby improving coercivity.

[0013] In order to weaken the magnetism of the grain boundary phase, it is important to increase the concentration of non-magnetic elements (Nb or B) in the grain boundary phase. By performing heat treatment under appropriate conditions, atomic diffusion between the main phase and the grain boundary phase can be promoted, and the concentrations of Nb and B in the grain boundary phase can be increased relative to the concentrations of Nb and B in the main phase.

[0014] The average Nb concentration in the main phase, TbCu7 type crystal phase, is n Nb1 and the maximum Nb concentration in the grain boundary phase is expressed as n Nb2 When expressed as Nb2 / n Nb1 By satisfying the relationship of n > 5, the coercive force can be improved. Nb2 / n Nb1 >10, and more preferably n Nb2 / n Nb1 >20. n Nb2 / n Nb1 The upper limit is not particularly limited, but is 500, for example.

[0015] The average B concentration in the TbCu7-type crystal phase is n B1 and the maximum B concentration in the grain boundary phase is expressed as n B2When expressed as B2 / n B1 By satisfying the relationship of n > 5, the coercive force can be improved. B2 / n B1 >7, and more preferably n B2 / n B1 >10. n B2 / n B1 The upper limit is not particularly limited, but is 500, for example.

[0016] The average R element concentration in the TbCu7-type crystal phase is n R1 , the minimum R element concentration in the grain boundary phase is n R When expressed as R2 / n R1 By satisfying the relationship of <0.5, the coercive force can be improved by the effect of promoting atomic diffusion of Nb and B between the main phase and the grain boundary phase. The relationship between the average R element concentrations in the main phase and the grain boundary phase is more preferably n R2 / n R1 <0.3, and more preferably n R2 / n R1 <0.1.

[0017] In order to obtain high coercivity and remanence, it is preferable to control the amount of each of the rare earth elements, M element, Nb, and B added. x Nb y B z M 100-x-y-z The magnetic material may contain unavoidable impurities.

[0018] The R element is a rare earth element that can impart large magnetic anisotropy and high coercivity to a magnetic material. Specifically, the R element is at least one element selected from the group consisting of yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Sm is particularly preferred. For example, when multiple elements including Sm are used as the R element, the Sm concentration should be 50 atomic % or more of the total amount of the R elements, thereby improving the magnetic properties, such as coercivity, of the magnetic material.

[0019] The amount x of the R element added is preferably a number that satisfies, for example, 4≦x≦10 atomic %. If x is less than 4 atomic %, precipitation of the α-Fe phase becomes significant, resulting in a decrease in coercivity. If x exceeds 10 atomic %, the concentration of the M element in the main phase decreases relatively, resulting in a decrease in remanence. The amount x of the R element added is preferably a number that satisfies 5≦x≦8 atomic %, and more preferably a number that satisfies 5.5≦x≦7.5 atomic %.

[0020] Niobium (Nb) is an element effective in promoting amorphization. Furthermore, appropriate heat treatment promotes diffusion from the main phase to the grain boundary phase, weakening the magnetism of the grain boundary phase and increasing the coercive force. The amount of Nb added, y, is preferably a number satisfying, for example, 0.1≦y≦8 atomic %. If x is less than 0.1, amorphization becomes difficult, or the effect of weakening the magnetism of the grain boundary phase is reduced, resulting in a decrease in coercive force. If x exceeds 8 atomic %, the remanence decreases. The amount of Nb added, y, is preferably a number satisfying 1≦y≦6 atomic %, more preferably a number satisfying 2≦y≦4 atomic %, and even more preferably a number satisfying 2.2≦y≦4 atomic %.

[0021] Up to 50 atomic % of Nb may be substituted with at least one element selected from the group consisting of zirconium (Zr), hafnium (Hf), tantalum (Ta), molybdenum (Mo), and tungsten (W). Zr, Hf, Ta, Mo, and W are elements effective in promoting amorphization and stabilizing the crystalline phase after heat treatment.

[0022] The M element is at least one element selected from the group consisting of Fe and Co, and is an element that is responsible for high saturation magnetization and even high remanence of the magnetic material. Since Fe has a higher magnetization than Co, it is preferable that 50 atomic % or more of the M element is Fe. By incorporating Co into the M element, the Curie temperature of the magnetic material increases, and it is possible to suppress the decrease in saturation magnetization in the high temperature range. Furthermore, by incorporating a small amount of Co, it is possible to increase the saturation magnetization more than when Fe is used alone. On the other hand, increasing the ratio of Co may result in a decrease in magnetic anisotropy. By appropriately controlling the ratio of Fe and Co, it is possible to simultaneously achieve high saturation magnetization, high anisotropy magnetic field, and high Curie temperature. When M in composition formula 1 is (Fe 1-p Co p ), the value of p is preferably 0.01≦p≦0.7, more preferably 0.05≦p≦0.5, and even more preferably 0.1≦p≦0.3. Up to 20 atomic % of the M element may be substituted with at least one element selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), aluminum (Al), silicon (Si), and gallium (Ga). The above elements contribute to, for example, improving the stability of the main phase, controlling the grain size, and controlling the composition and thickness of the grain boundary phase, thereby enhancing the coercive force and remanence.

[0023] Boron (B) is an element effective in promoting amorphization. By appropriately controlling the amount z of B added, an amorphous ribbon can be obtained by a highly industrially productive method such as a single-roll quenching method. Furthermore, B penetrates into the grain boundary phase and weakens the magnetism of the grain boundary phase, thereby increasing the coercive force. The amount z of B added is preferably a number that satisfies, for example, 0.1≦z≦12 atomic %, more preferably a number that satisfies 1≦z≦10 atomic %, and even more preferably a number that satisfies 5≦z≦10 atomic %.

[0024] The composition of the region where the Nb concentration is maximum in the grain boundary phase is represented by the composition formula 2:R x1 Nb y1 B z1 M 100-x1-y1-z1 (wherein R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x1 is a number satisfying x1≦6 atomic %, y1 is a number satisfying y1≧20 atomic %, and z1 is a number satisfying z1≧20 atomic %), the coercive force can be further increased by making the grain boundary phase an amorphous phase. Furthermore, an even higher coercive force can be obtained.

[0025] The magnet material of the embodiment may further contain an element A. The element A is at least one element selected from the group consisting of nitrogen (N), carbon (C), hydrogen (H), and phosphorus (P). The element A mainly invades interstitial sites of the TbCu7 phase, expanding the crystal lattice and changing the electronic structure, thereby changing the Curie temperature, magnetic anisotropy, and saturation magnetization. The element A does not necessarily have to be added, except as an unavoidable impurity.

[0026] The magnet material of the embodiment may be in the form of a quenched alloy ribbon produced by a liquid quenching method (melt-spun method), or may be in the form of powder obtained by pulverizing the quenched alloy ribbon. The powder may be produced by a gas atomization method or the like.

[0027] When the magnetic material of the embodiment is in the form of a quenched alloy ribbon, the ribbon preferably has an average thickness of 10 μm or more and 80 μm or less. If the ribbon is too thin, the proportion of a surface deterioration layer formed during quenching or heat treatment increases, resulting in a decrease in magnetic properties, such as remanence. If the ribbon is too thick, a distribution of the cooling rate within the ribbon is likely to occur, resulting in a decrease in coercive force. The average thickness of the ribbon is preferably 20 μm or more and 60 μm or less, and more preferably 30 μm or more and 50 μm or less.

[0028] The intrinsic coercivity of the magnetic material of the embodiment is 500 kA / m or more and 2500 kA / m or less, more preferably 600 kA / m or more and 2500 kA / m or less, and even more preferably 650 kA / m or more and 2500 kA / m or less, in order to improve heat resistance.

[0029] The remanence value of the magnetic material of the embodiment is 60 Am 2 / kg or more 170Am 2 / kg or less. The higher the residual magnetization, the more effective it is for miniaturizing motors and generators. The residual magnetization is preferably 75 Am 2 / kg or more 170Am 2 / kg or less, and more preferably 90Am 2 / kg or more 170Am 2 / kg or less.

[0030] For magnetic materials, it is important to have both high coercivity and high residual magnetization. The magnetic material of the embodiment has an intrinsic coercivity of 600 kA / m or more and a residual magnetization of 90 kA / m. 2 / kg or more can be achieved.

[0031] The composition of magnetic materials is measured using, for example, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscope-energy dispersive X-ray spectroscopy (TEM-EDX), scanning transmission electron microscope-energy dispersive X-ray spectroscopy (STEM-EDX), etc. X-ray diffraction can also be used to identify the phases that make up magnetic materials. The volume ratio of each phase is determined comprehensively by combining observations with electron microscopes or optical microscopes with X-ray diffraction, etc.

[0032] The average grain size of the main phase can be determined as follows: Among the main phase crystal grains identified using STEM-EDX in the cross section of the magnetic material, an arbitrary grain is selected, and the longest straight line A is drawn through the selected grain, with both ends tangent to another phase. Next, at the midpoint of this line A, a line B is drawn that is perpendicular to line A and tangent to both ends of another phase. The average length of lines A and B is defined as the diameter D of the phase. Using the above procedure, D is determined for one or more arbitrary phases. The above D is calculated for five fields of view for one sample, and the average of all Ds is defined as the diameter (D) of the phase. The cross section of the magnetic material is taken from substantially the center of the surface with the largest area of ​​the sample.

[0033] The compositions of the main phase and grain boundary phase can be measured by 3D atom probe tomography, which has atomic-level spatial resolution and high detection sensitivity in microscopic areas and is suitable for measuring element distribution at grain boundaries.

[0034] The average thickness of the quenched alloy ribbon can be determined, for example, as follows: The thickness of a ribbon piece 10 mm or longer is measured using a micrometer. The thickness of 10 or more ribbon pieces is measured, and the average value excluding the maximum and minimum values ​​is calculated to determine the average thickness of the ribbon.

[0035] The magnetic properties of the magnetic material, such as the coercive force and magnetization, are calculated using, for example, a vibrating sample magnetometer (VSM).

[0036] Next, an example of a method for manufacturing the magnetic material of the embodiment will be described. First, an alloy containing the predetermined elements required for the magnetic material is manufactured. For example, the alloy can be manufactured using an arc melting method, a high-frequency melting method, a mold casting method, a mechanical alloying method, a mechanical grinding method, a gas atomization method, a reduction diffusion method, or the like.

[0037] The alloy is melted and rapidly cooled, thereby rendering the alloy amorphous. The melted alloy is cooled, for example, using a liquid quenching method (melt-spun method). In the liquid quenching method, the molten alloy is injected into a roll rotating at high speed. The roll may be a single-roll or twin-roll type, and is typically made of copper or the like. The cooling rate of the molten alloy can be controlled by controlling the amount of molten alloy injected and the peripheral speed of the rotating roll. The degree to which the alloy is rendered amorphous can be controlled by the composition and cooling rate. Furthermore, if an amorphous alloy has already been obtained by using a gas atomization method or the like during the production of the alloy, there is no need to perform a separate rapid cooling process.

[0038] The amorphous alloy or alloy ribbon is subjected to heat treatment. This crystallizes the main phase, forming a metal structure having a main phase with microcrystals. For example, the alloy or alloy ribbon is heated at a temperature of 500°C to 1000°C in an inert atmosphere such as Ar or vacuum for 5 minutes to 300 hours.

[0039] If the temperature is too low, crystallization and homogenization will be insufficient, resulting in a decrease in coercivity. If the temperature is too high, a different phase will be generated due to decomposition of the main phase, resulting in a decrease in coercivity and squareness. The heating temperature is, for example, more preferably 520°C or higher and 800°C or lower, even more preferably 540°C or higher and 700°C or lower, and even more preferably 550°C or higher and 650°C or lower. If the heating time is too short, crystallization and homogenization will be insufficient, resulting in a decrease in coercivity.

[0040] If the heating time is too long, a different phase is generated due to decomposition of the main phase, etc., and the coercivity and squareness decrease. The heating time is preferably 15 minutes or more and 150 hours or less, more preferably 30 minutes or more and 120 hours or less, even more preferably 1 hour or more and 120 hours or less, even more preferably 2 hours or more and 100 hours or less, and even more preferably more than 3 hours and 80 hours or less.

[0041] After heating, the crystallized alloy or ribbon is cooled by furnace cooling, water quenching, gas quenching, oil quenching or the like.

[0042] The alloy may be infiltrated with element A. It is preferable to pulverize the alloy into powder before infiltrating the alloy with element A. When element A is nitrogen, the alloy can be nitrided and nitrogen can be infiltrated by heating the alloy at a temperature of 200°C to 700°C for 1 hour to 100 hours in an atmosphere of nitrogen gas or ammonia gas at a pressure of about 0.1 to 100 atmospheres. When element A is carbon, the alloy can be carbonized by heating the alloy at a temperature of 300°C to 900°C for 1 hour to 100 hours in an atmosphere of ethylene (C2H2), methane (CH4), propane (C3H8), or a pyrolysis gas of carbon monoxide (CO) gas or methanol (CH3OH). When the A element is hydrogen, hydrogen can be introduced into the alloy by heating the alloy at a temperature of 200°C to 700°C for 1 hour to 100 hours in an atmosphere of hydrogen gas or ammonia gas at a pressure of approximately 0.1 to 100 atmospheres. When the A element is phosphorus, phosphorus can be introduced into the alloy by phosphorizing the alloy.

[0043] A magnetic material is produced by the above process. Furthermore, magnetic powder is produced by pulverizing the alloy or ribbon. Furthermore, a permanent magnet is produced using the magnetic material or magnetic powder. An example of a magnet production process is shown below.

[0044] A permanent magnet having a sintered body can be formed by pressure-sintering a magnetic material. Pressure-sintering methods include heating and sintering after pressure application using a press molding machine, spark plasma sintering, hot pressing, and hot working. For example, the magnetic material is pulverized using a grinding device such as a jet mill or ball mill, and then subjected to magnetic field-oriented pressing at a pressure of about 1 ton (1000 kg) in a magnetic field of about 1 T to 2 T to obtain a molded body. The resulting molded body is heated and sintered in an inert gas atmosphere such as Ar or vacuum, producing a sintered body. A permanent magnet can be manufactured by appropriately heat-treating the sintered body in an inert atmosphere.

[0045] Furthermore, bonded magnets can be produced by crushing the magnetic material, binding the crushed material with a binder, and mixing the crushed material. Examples of binders that can be used include thermosetting resins, thermoplastic resins, low-melting-point alloys, and rubber materials. Molding methods that can be used include compression molding and injection molding.

[0046] A permanent magnet comprising the magnetic material of the embodiment can be used in rotating electrical machines such as various motors and generators. It can also be used as a fixed magnet or variable magnet in a variable magnetic flux motor or variable magnetic flux generator. By applying the permanent magnet to a rotating electrical machine, effects such as high efficiency, miniaturization, and cost reduction can be obtained.

[0047] The rotating electric machine may be mounted on, for example, a railway vehicle (one example of a vehicle) used for rail transport. By using a highly efficient rotating electric machine such as the rotating electric machine of the embodiment, the railway vehicle can be run with less energy.

[0048] The rotating electric machine may be mounted on an automobile (another example of a vehicle) such as a hybrid automobile or an electric automobile. The rotating electric machine may also be mounted on, for example, industrial equipment (industrial motors), air conditioning equipment (air conditioner / water heater compressor motors), wind power generators, or elevators (hoists). [Example]

[0049] (Example 1, Comparative Example 1) Appropriate amounts of Sm, Fe, Co, Nb, and B raw materials were weighed and prepared using a high-frequency melting method. The alloy was then melted, and the resulting molten metal was quenched using a single-roll method to produce a quenched alloy ribbon. The roll peripheral speed was 15 m / s. X-ray diffraction of the resulting alloy ribbon revealed a broad diffraction pattern, suggesting the formation of an amorphous phase. The intrinsic coercivity of the alloy ribbon was low at 1.2 kA / m, confirming the formation of an amorphous phase throughout the alloy ribbon. The alloy ribbon was then heat-treated at 625°C in an Ar atmosphere and then cooled to room temperature. The heat treatment time was 9 hours in Example 1 and 1 hour in Comparative Example 1. The composition of the alloy ribbon immediately after quenching was evaluated using ICP-AES. The coercivity and remanence of the heat-treated alloy ribbon-shaped magnet material were also evaluated using VSM. The evaluation results for the composition, intrinsic coercivity, and remanence of the magnet material are shown in Table 1. In addition, "Fe bal. " indicates that the remainder is Fe.

[0050] The compositions of the main phase and the grain boundary phase were analyzed using a three-dimensional atom probe for the alloy ribbons of Example 1 and Comparative Example 1. Fig. 2 shows an example of the three-dimensional atom probe analysis results (concentration distributions of Nb and B) for Example 1. Fig. 3 shows an example of the three-dimensional atom probe analysis results (concentration distributions of Nb and B) for Comparative Example 1.

[0051] 2 and 3 show that the concentrations of Nb and B are increased in the grain boundary phase in both the samples of Example 1 and Comparative Example 1, but this tendency is more pronounced in the sample of Example 1 (heat treatment time: 9 hours) than in the sample of Comparative Example 1 (heat treatment time: 1 hour). Therefore, focusing on the grain boundary phase, the concentration distribution was examined in more detail. FIG. 4 shows an example of the concentration distribution of each of the elements Sm, Fe, Co, Nb, and B in the grain boundary phase in Example 1. FIG. 5 shows an example of the concentration distribution of each of the elements Sm, Fe, Co, Nb, and B in the grain boundary phase in Comparative Example 1. It is clear from FIGS. 4 and 5 that the concentrations of Nb and B in the grain boundary phase are increased in Example 1 compared to Comparative Example 1, while the concentration of the R element (Sm) is conversely decreased.

[0052] The average Nb concentration in the main phase (TbCu7 phase) Nb1 ), average B concentration (n B1 ), and the average R element (Sm) concentration were determined as follows. First, the average values ​​of the analytical values ​​at two locations in the main phase, sandwiching the grain boundary phase, were calculated, and the same analysis was performed on three locations in the grain boundary phase. These average values ​​were calculated to determine the average Nb concentration, average B concentration, and average R element (Sm) concentration in the main phase (TbCu7 phase). The calculated values ​​are shown in Table 2. The maximum Nb concentration (n Nb2 ), maximum B concentration (n B2 ), minimum R element (Sm) concentration (n R2 ) was also calculated as the average of the maximum and minimum analytical values ​​at the three grain boundaries, and is shown in Table 2. From these values, n Nb2 / n Nb1 , n B2 / n B1 , n R2 / n R1 The values ​​were calculated and are shown in Table 2.

[0053] [Table 1]

[0054] [Table 2]

[0055] The magnet material of Example 1 is n Nb2 / n Nb1 reached 24.9, and n B2 / n B1 reached 11.7, and the concentration of Nb and B in the grain boundary phase was significant compared to the magnetic material of Comparative Example 1. Furthermore, the magnetic material of Example 1 had a minimum R element (Sm) concentration n R2 As shown in Table 1, the magnetic material of Example 1 having such a grain boundary phase has a 92.4Am 2 / kg and a high intrinsic coercivity of 655kA / m

[0056] (Examples 2-9, Comparative Examples 2 and 3) Rapidly quenched alloy ribbons were produced from the raw materials Sm, Fe, Co, Nb, and B in the same manner as in Example 1. The obtained alloy ribbons were heat-treated in an Ar atmosphere at a predetermined temperature for a predetermined time, and then cooled to room temperature. The composition of the alloy ribbons immediately after quenching was evaluated using ICP-AES. In addition, the coercivity and remanence of the heat-treated alloy ribbon-shaped magnetic material were evaluated using VSM. Table 3 shows the evaluation results of the composition of the alloy ribbons, the coercivity of the magnetic material, and the remanence.

[0057] The magnet materials of Examples 2 to 9 are all n Nb2 / n Nb1 >5, n B2 / n B1 >5, n R2 / n R1 <0.5, and both have an intrinsic coercivity of 600kA / m or more and a 2 / kg or more. In addition, the magnetic materials of Examples 2 to 9 have a region in the grain boundary phase where the Nb concentration is maximum, which is represented by the above composition formula 2:R x1 Nb y1 B z1 M 100-x1-y1-z1 The composition was represented by the formula:

[0058] On the other hand, the magnet materials of Comparative Examples 2 and 3 all had n Nb2 / n Nb1 >5, n B2 / n B1 >5, n R2 / n R1<0.5) was not satisfied. The magnet materials of Comparative Examples 2 and 3 were produced by heat treating the same rapidly solidified alloy ribbon as the magnet material of Example 1, but the heat treatment conditions were inappropriate, so a large coercive force was not obtained. In Comparative Example 2, the heat treatment temperature and heat treatment time were insufficient, so atomic diffusion between the main phase and the grain boundary phase was insufficient, which resulted in a small effect of weakening the magnetism of the grain boundary phase, and a high intrinsic coercive force was not obtained. In Comparative Example 3, the heat treatment temperature was too high, so the precipitation of the α-Fe phase was significant, and the intrinsic coercive force was significantly reduced. Furthermore, in the magnet materials of Comparative Examples 2 and 3, the region in the grain boundary phase where the Nb concentration is maximum is located within the region of the above composition formula 2:R x1 Nb y1 B z1 M 100-x1-y1-z1 The composition was different from that represented by

[0059] [Table 3]

[0060] (Examples 10 to 13) A quenched alloy ribbon was produced from each raw material, such as the R element, Fe, Co, Nb, and B, in the same manner as in Example 1. The obtained alloy ribbon was heat-treated in an Ar atmosphere at a predetermined temperature for a predetermined time, and then cooled to room temperature. The composition of the alloy ribbon immediately after quenching was evaluated using ICP-AES. In addition, the coercivity and remanence of the alloy ribbon-shaped magnetic material after the heat treatment were evaluated using VSM. Table 3 shows the evaluation results of the composition of the alloy ribbon, the coercivity of the magnetic material, and the remanence.

[0061] The magnet materials of Examples 10 to 13 are all n Nb2 / n Nb1 >5, n B2 / n B1 >5, n R2 / n R1 <0.5, and both have an intrinsic coercivity of 600kA / m or more and a 2 / kg or more. In addition, the magnetic materials of Examples 10 to 13 have a region in the grain boundary phase where the Nb concentration is maximum, which is represented by the above composition formula 2:Rx1 Nb y1 B z1 M 100-x1-y1-z1 The composition was represented by the formula:

[0062] [Table 4]

[0063] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0064] 101...Crystal grain, 102...Grain boundary.

Claims

1. Composition 1: R ｘ Nb ｙ B ｚ M １００－ｘ－ｙ－ｚ (R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x is a number satisfying 4≦x≦10 atomic %, y is a number satisfying 0.1≦y≦8 atomic %, and z is a number satisfying 0.1≦z≦12 atomic %). is represented by further comprising at least one element selected from the group consisting of nitrogen, carbon, hydrogen, and phosphorus; TbCu ７ a main phase having a crystalline phase; and a grain boundary phase, The TbCu ７ The average Nb concentration in the crystalline phase is n Ｎｂ１ and the maximum Nb concentration in the grain boundary phase is expressed as n Ｎｂ２ When expressed as Ｎｂ２ / n Ｎｂ１ A magnetic material that satisfies the relationship >5.

2. Composition 1: R ｘ Nb ｙ B ｚ M １００－ｘ－ｙ－ｚ (R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x is a number satisfying 4≦x≦10 atomic %, y is a number satisfying 0.1≦y≦8 atomic %, and z is a number satisfying 0.1≦z≦12 atomic %). is represented by further comprising at least one element selected from the group consisting of nitrogen, carbon, hydrogen, and phosphorus; TbCu ７ a main phase having a crystalline phase; and a grain boundary phase, The TbCu ７ The average B concentration in the type crystalline phase is n Ｂ１ and the maximum B concentration in the grain boundary phase is expressed as n Ｂ２ When expressed as Ｂ２ / n Ｂ１ A magnetic material that satisfies the relationship >5.

3. Composition 1: R ｘ Nb ｙ B ｚ M １００－ｘ－ｙ－ｚ (R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x is a number satisfying 4≦x≦10 atomic %, y is a number satisfying 0.1≦y≦8 atomic %, and z is a number satisfying 0.1≦z≦12 atomic %). is represented by further comprising at least one element selected from the group consisting of nitrogen, carbon, hydrogen, and phosphorus; TbCu ７ a main phase having a crystalline phase; and a grain boundary phase, The TbCu ７ The average R element concentration in the type crystal phase is n Ｒ１ The minimum R element concentration in the grain boundary phase is expressed as n Ｒ２ When expressed as Ｒ２ / n Ｒ１ <0.

5.

4. The TbCu ７ The average B concentration in the type crystalline phase is n Ｂ１ and the maximum B concentration in the grain boundary phase is expressed as n Ｂ２ When expressed as Ｂ２ / n Ｂ１ The magnetic material according to claim 3 , wherein the relationship of ∑R ∑ i = 1 ∑ j ...

5. The TbCu ７ The average Nb concentration in the crystalline phase is n Ｎｂ１ and the maximum Nb concentration in the grain boundary phase is expressed as n Ｎｂ２ When expressed as Ｎｂ２ / n Ｎｂ１ The magnetic material according to claim 2 , wherein the relationship of ∑R ∑ i = 1 ∑ b = 1 ∑ r = 1 ∑ r = 1 ∑ b ...

6. Composition 1: R ｘ Nb ｙ B ｚ M １００－ｘ－ｙ－ｚ (R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x is a number satisfying 4≦x≦10 atomic %, y is a number satisfying 0.1≦y≦8 atomic %, and z is a number satisfying 0.1≦z≦12 atomic %). is represented by further comprising at least one element selected from the group consisting of nitrogen, carbon, hydrogen, and phosphorus; TbCu ７ a main phase having a crystalline phase; and a grain boundary phase, The region in the grain boundary phase where the Nb concentration is maximum is Formula 2: R ｘ１ Nb ｙ１ B ｚ１ M １００－ｘ１－ｙ１－ｚ１ (R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Fe and Co, x1 is a number satisfying x1≦6 atomic %, y1 is a number satisfying y1≧20 atomic %, and z1 is a number satisfying z1≧20 atomic %). The magnetic material is represented by

7. 7. The magnetic material according to claim 1, wherein 50 atomic % or more of the R elements are Sm.

8. 8. The magnetic material according to claim 1, wherein 50 atomic % or less of Nb is substituted with at least one element selected from the group consisting of Zr, Hf, Ta, Mo, and W.

9. 9. The magnetic material according to claim 1, wherein 50 atomic % or more of the M element is Fe.

10. 10. The magnetic material according to claim 1, wherein 20 atomic % or less of the M element is substituted with at least one element selected from the group consisting of Ti, V, Cr, Mn, Ni, Cu, Zn, Al, Si, and Ga.

11. 11. The magnetic material according to claim 1, wherein in said composition formula 1, the content of yttrium is 0.66 atomic % or less.

12. 11. The magnetic material according to claim 1, wherein in said composition formula 1, the content of cobalt is 16.0 atomic % or less.

13. The magnetic material according to claim 1 , wherein the grain boundary phase is an amorphous phase.

14. 14. The magnetic material according to claim 1, which has an intrinsic coercive force of 600 kA / m or more.

15. Residual magnetization is 90 Am ２ 15. The magnetic material according to claim 1, wherein the tensile strength is 1 / kg or more.

16. The magnetic material according to any one of claims 1 to 15; A binder and A permanent magnet comprising:

17. A permanent magnet comprising a sintered body of the magnetic material according to any one of claims 1 to 15.

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