Magnetic material and permanent magnet

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] The embodiments relate to magnetic materials and permanent magnets. [Background technology]

[0002] Permanent magnets are used in a wide range of products including, for example, rotating electrical machines such as motors and generators, electrical equipment such as speakers and measuring instruments, and vehicles such as automobiles, railway cars, etc. In recent years, there has been a demand for the above-mentioned products to be more compact, more efficient, and have higher output, 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 provide large magnetic anisotropy due to the behavior of the 4f electrons of the rare earth elements in the crystal field. This allows for a large coercive force to be obtained. [Prior art documents] [Patent documents]

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

[0005] The problem that the present invention seeks to solve is to increase the coercivity 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 has 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 represented by n Nb1 The maximum Nb concentration in the grain boundary phase is expressed as n Nb2 When expressed as n Nb2 / n Nb1 >5. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic diagram showing an example of a metal structure. [Diagram 2] FIG. 2 is a diagram showing the results of three-dimensional atom probe analysis (concentration distribution of Nb and B) in Example 1. [Diagram 3] FIG. 13 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. [Diagram 5] FIG. 4 is a diagram showing the concentration distribution of each element in the grain boundary phase of Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 having a TbCu7 type crystal phase containing a high concentration of the M element as a main phase. By increasing the concentration of the M element in the main phase, the saturation magnetization can be improved, and thus the remanence can be improved. The magnet material may be substantially composed of a TbCu7 type crystal phase as a main phase and a grain boundary phase, but may also contain other phases such as a microcrystalline phase and an impurity phase. The main phase is the phase with the highest volume occupancy among the crystal phases and amorphous phases in the magnet material. FIG. 1 is a schematic diagram showing an example of the structure of a metal structure. FIG. 1 shows a crystal grain 101 having a TbCu7 type crystal phase and a grain boundary 102 provided between a plurality of crystal grains 101 and having a grain boundary phase.

[0009] In addition to the rare earth elements and M element, the addition of Nb and B enhances the ability to form an amorphous phase, and the size of the main phase crystal grains after heat treatment is uniform, thereby enhancing the remanence and coercivity. The above-mentioned magnet materials are in the form of powder or thin strip, and are molded to produce permanent magnets. 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, and this has led to an increased demand for improved heat resistance of permanent magnets. In order to improve heat resistance, it is necessary to improve the coercivity of permanent magnets and magnet materials.

[0010] In a magnetic material having a large magnetic anisotropy, an effective method for achieving a high coercive force is, for example, to refine the crystal grains of the magnetic material, for example, by producing an amorphous ribbon using a liquid quenching method and then subjecting the ribbon to an appropriate heat treatment to cause the precipitation and growth of crystal grains.

[0011] By refining the main phase with high magnetic anisotropy, each crystal grain is more likely to be in a single magnetic domain state, suppressing the generation of reverse magnetic domains and the propagation of magnetic domain walls, and achieving high coercivity. If the crystal grain size is too small or too large, the coercivity decreases, so 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. In addition, by narrowing the particle size distribution of the main phase, the squareness in the demagnetization characteristics of the magnetic material can be improved, thereby improving the maximum energy product.

[0012] Another effective method for improving coercivity is to form a grain boundary phase between crystal grains to weaken the magnetic coupling between the crystal grains. By weakening the magnetism of the grain boundary phase, ideally by making the grain boundary phase nonmagnetic, the effect of suppressing the generation and propagation of reverse magnetic domains can be improved, 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 carrying out heat treatment under appropriate conditions, atomic diffusion between the main phase and the grain boundary phase can be promoted, and the concentration of Nb or B in the grain boundary phase can be increased relative to the concentration of Nb or B in the main phase.

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

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

[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 n R2 / n R1 By satisfying the relationship of n<0.5, the atomic diffusion of Nb and B between the main phase and the grain boundary phase can be promoted, and thus the coercive force can be improved. The relationship between the average R element concentration in the main phase and the grain boundary phase is 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, the 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 bring about large magnetic anisotropy in the magnet material and can impart high coercivity. 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), and it is particularly preferable to use Sm. For example, when multiple elements including Sm are used as the R element, the Sm concentration is set to 50 atomic % or more of the total amount of the R element, thereby improving the magnetic properties of the magnet material, such as the coercivity.

[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 %, the precipitation of the α-Fe phase becomes significant, and the coercive force decreases. If x exceeds 10 atomic %, the concentration of the M element in the main phase relatively decreases, and the remanence decreases. The amount x of the R element added is more preferably a number that satisfies 5≦x≦8 atomic %, and further preferably a number that satisfies 5.5≦x≦7.5 atomic %.

[0020] Niobium (Nb) is an element effective in promoting amorphization. In addition, appropriate heat treatment promotes diffusion from the main phase to the grain boundary phase, and the coercive force can be increased by weakening the magnetism of the grain boundary phase. The amount of Nb added y is preferably a number that satisfies, 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 becomes small, resulting in a decrease in coercive force, and if it exceeds 8 atomic %, it will result in a decrease in remanence. The amount of Nb added y is preferably a number that satisfies 1≦y≦6 atomic %, furthermore a number that satisfies 2≦y≦4 atomic %, and furthermore a number that satisfies 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 crystal 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 high remanent magnetization 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 adding Co to the M element, the Curie temperature of the magnetic material is increased, and the decrease in saturation magnetization in the high temperature region can be suppressed. Furthermore, by adding a small amount of Co, the saturation magnetization can be increased 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 anisotropic magnetic field, and high Curie temperature. When M in composition formula 1 is (Fe 1-p Co p ), the preferred value of p is 0.01≦p≦0.7, more preferably 0.05≦p≦0.5, and even more preferably 0.1≦p≦0.3. 20 atomic % or less of the M element may be replaced 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 residual magnetization.

[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 method with high industrial productivity such as a single roll quenching method. In addition, 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, whereby 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 penetrates into the interstitial sites of the TbCu7 phase, and can change the Curie temperature, magnetic anisotropy, and saturation magnetization by expanding the crystal lattice and changing the electronic structure. 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 deteriorated layer formed during quenching or heat treatment increases, and the magnetic properties, such as residual magnetization, decrease. If the ribbon is too thick, a distribution of the cooling rate is likely to occur within the ribbon, and the coercive force decreases. 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 according to 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 residual magnetization value of the magnet material of the embodiment is 60Am 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 75Am 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 Am. 2 / kg or more can be achieved.

[0031] The composition of the magnet material is measured by, 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. In addition, X-ray diffraction can be used to identify the phases that make up the magnet material. The volume ratio of each phase is comprehensively determined by combining observation with an electron microscope or optical microscope with X-ray diffraction, etc.

[0032] The average grain size of the main phase is 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 for the selected grain, with both ends touching another phase. Next, at the midpoint of line A, a line B is drawn that is perpendicular to line A and touches both ends of another phase. The average of the lengths 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 D 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 having 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: A ribbon piece having a length of 10 mm or more is measured for thickness using a micrometer. The average thickness of the ribbon is calculated by measuring the thickness of 10 or more ribbon pieces and averaging the values ​​excluding the maximum and minimum values.

[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 atomizing method, a reduction diffusion method, or the like.

[0037] The alloy is melted and quenched. This makes the alloy amorphous. The molten alloy is cooled, for example, by 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 type or a twin roll type, and is mainly 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 of amorphization of the alloy can be controlled by the composition and the cooling rate. In addition, if an amorphous alloy has already been obtained by using a gas atomization method or the like during the preparation of the alloy, it is not necessary to carry out a quenching process again.

[0038] The amorphous alloy or alloy ribbon is subjected to a heat treatment. This allows the main phase to be crystallized, 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 for 5 minutes to 300 hours in an inert atmosphere such as Ar or vacuum.

[0039] If the temperature is too low, the crystallization and homogenization are insufficient, and the coercive force decreases. If the temperature is too high, a different phase is generated due to decomposition of the main phase, and the coercive force and squareness decrease. The heating temperature is, for example, more preferably 520°C to 800°C, even more preferably 540°C to 700°C, and even more preferably 550°C to 650°C. If the heating time is too short, the crystallization and homogenization are insufficient, and the coercive force decreases.

[0040] If the heating time is too long, a different phase is generated due to decomposition of the main phase, and the coercive force and squareness are reduced. 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, more preferably 1 hour or more and 120 hours or less, more preferably 2 hours or more and 100 hours or less, and more preferably more than 3 hours and 80 hours or less.

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

[0042] The A element may be infiltrated into the alloy. It is preferable to pulverize the alloy into powder before the step of infiltrating the A element into the alloy. When the A element is nitrogen, the alloy is heated 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 to nitride the alloy and allow nitrogen to infiltrate into the alloy. When the A element is carbon, the alloy is heated at a temperature range of 300°C to 900°C for 1 hour to 100 hours in an atmosphere of ethylene (C2H2), methane (CH4), propane (C3H8), or carbon monoxide (CO) gas or methanol (CH3OH) decomposition gas at a pressure of about 0.1 to 100 atmospheres to carbonize the alloy, allowing carbon to infiltrate into the alloy. When the A element is hydrogen, hydrogen can be absorbed 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 about 0.1 to 100 atmospheres. When the A element is phosphorus, phosphorus can be absorbed into the alloy by phosphorizing the alloy.

[0043] A magnetic material is produced by the above process. The alloy or ribbon is pulverized to produce magnetic powder. A permanent magnet is produced by 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. As a method of pressure sintering, a method of applying pressure with a press molding machine, followed by heating and sintering, a method using a discharge plasma sintering method, a method using a hot press, a method using a hot working method, etc. can be applied. For example, the magnetic material is pulverized using a pulverizing device such as a jet mill or a ball mill, and a molded body is obtained by magnetic field orientation pressing at a pressure of about 1 ton (1000 kg) in a magnetic field of about 1 T to 2 T. The obtained molded body is heated and sintered in an inert gas atmosphere such as Ar or in a vacuum to produce a sintered body. A permanent magnet can be manufactured by appropriately applying heat treatment to the sintered body in an inert atmosphere, etc.

[0045] In addition, the above-mentioned magnet material can be crushed, and the crushed material can be fixed with a binder and mixed to produce a bonded magnet. Examples of the binder that can be used include thermosetting resin, thermoplastic resin, low melting point alloy, and rubber material. Examples of the molding method that can be used include compression molding and injection molding.

[0046] A permanent magnet having the magnetic material of the embodiment can be used in rotating electric machines such as various motors and generators. It can also be used as a fixed magnet or a variable magnet in a variable magnetic flux motor or a variable magnetic flux generator. By applying the permanent magnet to a rotating electric 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 railroad car (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 railroad car can be run with reduced energy.

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

[0049] (Example 1, Comparative Example 1) Each of the raw materials Sm, Fe, Co, Nb, and B was appropriately weighed, and an alloy was prepared by high-frequency melting. Next, the alloy was melted, and the obtained molten metal was quenched by a single roll method to prepare a quenched alloy ribbon. The roll peripheral speed was 15 m / s. The obtained alloy ribbon showed a broad diffraction pattern as a result of X-ray diffraction, suggesting the formation of an amorphous phase. In addition, the intrinsic coercivity of the alloy ribbon was low at 1.2 kA / m, and it was confirmed that an amorphous phase was formed throughout the alloy ribbon. Next, the above alloy ribbon was subjected to heat treatment at a temperature of 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. In addition, the coercivity and remanence of the alloy ribbon-shaped magnet material after the heat treatment were evaluated using VSM. Table 1 shows the composition of the magnet material, the intrinsic coercivity of the magnet material, and the evaluation results of the remanence. 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 result (concentration distribution of Nb and B) in Example 1. Fig. 3 shows an example of the three-dimensional atom probe analysis result (concentration distribution of Nb and B) in Comparative Example 1.

[0051] From Fig. 2 and Fig. 3, it can be seen 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 element of 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 element of Sm, Fe, Co, Nb, and B in the grain boundary phase in Comparative Example 1. From Fig. 4 and Fig. 5, it is clear that the concentrations of Nb and B in the grain boundary phase in Example 1 increase, while the concentration of the R element (Sm) decreases, as compared with Comparative Example 1.

[0052] Average Nb concentration in the main phase (TbCu7 phase) (n Nb1 ), average B concentration (n B1 ), and the average R element (Sm) concentration were determined as follows. First, the average values ​​of the analysis values ​​at two locations in the main phase, one on either side of the grain boundary phase, were obtained, 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 The concentration of Nb and B in the grain boundary phase is significant compared to the magnet material of Comparative Example 1. The magnet material of Example 1 also has a minimum R element (Sm) concentration n R2 The magnet material of Example 1 having such a grain boundary phase has a 92.4Am 2 / kg while exhibiting a high intrinsic coercivity of 655 kA / m

[0056] (Examples 2-9, Comparative Examples 2 and 3) A quenched alloy ribbon was produced from each of the raw materials Sm, Fe, Co, Nb, and B in the same manner as in Example 1. The obtained alloy ribbon was subjected to heat treatment under conditions of a specified temperature and time in an Ar atmosphere, 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 magnet material after the heat treatment were evaluated using VSM. The evaluation results of the composition of the alloy ribbon, the coercivity of the magnet material, and the remanence are shown in Table 3.

[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 600 kA / m or more and a 2 / kg or more. In addition, in the magnet materials of Examples 2 to 9, the region in the grain boundary phase where the Nb concentration is maximum 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 Example 2 and Comparative Example 3 all had n Nb2 / n Nb1 >5, n B2 / n B1 >5, n R2 / n R1<0.5). The magnet materials of Comparative Examples 2 and 3 were produced by subjecting the same quenched alloy ribbon as the magnet material of Example 1 to heat treatment, but the heat treatment conditions were inappropriate, so no large coercive force was 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, and as a result, the effect of weakening the magnetism of the grain boundary phase was small, and no high intrinsic coercive force was obtained. In Comparative Example 3, the heat treatment temperature was too high, so precipitation of the α-Fe phase was large, 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 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 of the raw materials, such as the R element, Fe, Co, Nb, and B, in the same manner as in Example 1. The obtained alloy ribbon was subjected to heat treatment under conditions of a specified temperature and time in an Ar atmosphere, and then cooled to room temperature. The composition of the alloy ribbon immediately after quenching was evaluated using ICP-AES. In addition, the coercive force and remanence of the alloy ribbon-shaped magnet material after the heat treatment were evaluated using VSM. The evaluation results of the composition of the alloy ribbon, the coercive force of the magnet material, and the remanence are shown in Table 3.

[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 600 kA / m or more and a 2 / kg or more. In addition, in the magnet materials of Examples 10 to 13, the region in the grain boundary phase where the Nb concentration is maximum 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 can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

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

Claims

1. Composition formula 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 crystal phase is n Ｎｂ１ 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 formula 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 crystal phase is n Ｂ１ 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 formula 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 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 A magnetic material that satisfies the relationship:

4. The TbCu ７ The average B concentration in the crystal phase is n Ｂ１ 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 , which satisfies the relationship:

5. The TbCu ７ The average Nb concentration in the crystal phase is n Ｎｂ１ 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 magnetic material satisfies the relationship of >5.

6. Composition formula 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 Composition 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 %). A magnet material represented by:

7. 7. The magnetic material according to claim 1, wherein 50 atomic % or more of the R element is 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, having an intrinsic coercivity of 600 kA / m or more.

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

16. A magnetic material according to any one of claims 1 to 15; A binder; 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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