Permanent magnet, manufacturing method thereof, and device

Abstract

Provided are: a permanent magnet having a high coercive force; a method for manufacturing same; and a device using said permanent magnet.　This permanent magnet has a composition represented by formula (1).　Formula (1): (R1-xZrx)a(T1-yMy)bBc. Wherein, in formula (1), R represents at least one selected from rare earth elements, T represents at least one selected from the group consisting of Fe, Co, and Ni, M represents at least one selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W, and a, b, and c represent atomic percentages and x and y represent respective proportions of Zr and M, and are numbers that respectively satisfy formulae: 5≤a≤12, b=100-(a+c), 0.1≤c≤20, 0.01≤x≤0.5, and 0.01≤y≤0.5.

Description

[Technical Field]

[0001] The present invention relates to a permanent magnet, a manufacturing method thereof, and a device. [Background technology]

[0002] There is a demand for permanent magnets with high remanence and high heat resistance. One candidate material for such a magnet is ThMn, which has high saturation magnetization and a high Curie temperature. 12 SmFe with a tetragonal crystal structure 12 compounds based on

[0003] For example, Patent Document 1 describes ThMn as a permanent magnet that has excellent saturation magnetization and coercive force, and has improved temperature characteristics of coercive force. 12 A permanent magnet is disclosed that is made of an alloy containing a hard magnetic phase having a tetragonal crystal structure and a non-magnetic phase.

[0004] In addition, Patent Document 2 discloses ThMn as a magnetic material that increases saturation magnetization. 12 A magnetic material having a specific composition and a main phase consisting of a crystalline phase is disclosed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-189206 [Patent Document 2] Japanese Patent Application Publication No. 2018-125512 Summary of the Invention

[0006] The above-mentioned ThMn 12 In permanent magnets having a tetragonal crystal structure, there is a demand for higher coercivity.

[0007] The present invention solves the above problems and is based on the 12The present invention aims to provide a permanent magnet having a tetragonal crystal structure and high coercive force, a method for manufacturing the same, and a device using the permanent magnet. [Means for solving the problem]

[0008] The permanent magnet according to the present invention is It has a composition represented by the following formula (1). Equation (1): (R 1-x Zr x ) a (T 1-y M y ) b B c However, in formula (1), R is at least one selected from rare earth elements, T is at least one selected from the group consisting of Fe, Co, and Ni; M represents at least one selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W; a, b, and c each represent atomic %, x and y represent the ratio of Zr and M, respectively, and are numbers that satisfy the following formula: 5≦a≦12, b=100-(a+c), 0.1≦c≦20, 0.01≦x≦0.5, 0.01≦y≦0.5.

[0009] One embodiment of the permanent magnet is ThMn 12 The crystal grains have a main phase having a crystal structure of the type, and crystal grain boundaries, and the crystal grain boundaries contain an amorphous phase.

[0010] In one embodiment of the permanent magnet, 50 atomic % or more of the R is Sm.

[0011] In one embodiment of the permanent magnet, 50 atomic % or more of the T is Fe.

[0012] In one embodiment of the permanent magnet, the a is a number that satisfies 5≦a≦8.

[0013] In one embodiment of the permanent magnet, the coercive force (Hcj) is 1.8 kOe or more.

[0014] One embodiment of the permanent magnet has a Curie temperature above 400°C.

[0015] In one embodiment of the permanent magnet, the proportion (atomic %) of the B element in the crystal grain boundaries is 10 times or more the proportion of the B element in the crystal grains.

[0016] One embodiment of the permanent magnet is a magnet having a ThMn 12 The peak intensity (I ThMn12 ) and the peak intensity of the peak corresponding to the 110 plane of α-iron (I α-Fe ) intensity ratio (I α-Fe / I ThMn12 ) is less than or equal to 1.0.

[0017] The method for producing a permanent magnet according to the present invention includes the steps of: A step (I) of preparing a molten metal having a composition represented by the above formula (1); The molten metal was added to the 2 ~10 7 Step (II) of rapidly cooling the mixture at 1000 K / sec to form an alloy; (III) a step of pulverizing the alloy to form a powder; Step (IV) of molding the powder into a molded body; a step (V) of sintering the compact to form a sintered body; and step (VI) of heat-treating the sintered body and then quenching it.

[0018] A device according to the present invention is characterized by comprising the above permanent magnet. [Effects of the Invention]

[0019] According to the present invention, ThMn 12 The present invention provides a permanent magnet having a tetragonal crystal structure and high coercivity, a method for manufacturing the same, and a device using the permanent magnet. [Brief explanation of the drawings]

[0020] [Figure 1] 1 shows X-ray diffraction spectra of permanent magnets of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0021] The permanent magnet, manufacturing method, and device of this embodiment will be described below. Unless otherwise specified, the symbol "to" indicating a range of values ​​includes the lower and upper limits.

[0022] [Permanent magnet] The permanent magnet of this embodiment (hereinafter also referred to as the present permanent magnet) is characterized by having a composition represented by the following formula (1). Equation (1): (R 1-x Zr x ) a (T 1-y M y ) b B c However, in formula (1), R is at least one selected from rare earth elements, T is at least one selected from the group consisting of Fe, Co, and Ni; M represents at least one selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W; a, b, and c each represent atomic %, x and y represent the ratio of Zr and M, respectively, and are numbers that satisfy the following formula: 5≦a≦12, b=100-(a+c), 0.1≦c≦20, 0.01≦x≦0.5, 0.01≦y≦0.5.

[0023] In formula (1), R represents a rare earth element. In this embodiment, rare earth elements are a collective term for elements including lanthanides from La (lanthanum) to Lu (lutetium), Sc (scandium), and Y (yttrium). R contains one or more elements selected from the above rare earth elements. By containing R in a proportion within the range satisfying formula (1), a permanent magnet having high magnetic anisotropy and high coercive force can be obtained. From the viewpoints of magnetic anisotropy and coercive force, R preferably contains one or more elements selected from Sm, Pr, Nd, Ce, and La, and more preferably contains Sm. Furthermore, from the viewpoints of magnetic anisotropy and coercive force, it is preferable that 50 atomic % or more of R is Sm, preferably 80 atomic % or more of R is Sm, and more preferably R is substantially Sm.

[0024] The permanent magnet contains Zr in a range where the ratio (atomic %) of R to Zr is (1-x):x. By containing Zr within this range, it is possible to suppress the content of the M element, which will be described later, while achieving the desired ThMn 12 The crystal structure of the ThMn type can be stabilized, resulting in an improvement in saturation magnetization. 12 From the viewpoint of stabilizing the crystal structure of the type, x may be 0.01 to 0.5, and further from the viewpoint of magnetic anisotropy and coercive force, it is preferably 0.2 or less.

[0025] The total content of R and Zr in the entire permanent magnet (a) is ThMn 12 In order to make the type crystal structure the main phase, a is 5 to 12. In order to increase the magnetization, a is preferably 10 or less, and more preferably 8 or less.

[0026] In formula (1), T represents at least one element selected from the group consisting of Fe, Co, and Ni. Each element in T contributes to the magnetization of the permanent magnet. In order to increase the magnetization, it is preferable that T contains Fe. Furthermore, in order to increase the Curie temperature and improve the heat resistance, it is preferable that T contains Co. In order to increase the magnetization, it is preferable that 50 atomic % or more of T is Fe, and it is more preferable that 60 atomic % or more is Fe. Furthermore, for example, when Fe and Co are used in combination, the ratio of Fe to Co (atomic %) is preferably 60:40 to 95:5, and more preferably 70:30 to 80:20.

[0027] In formula (1), M represents at least one element selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W. The permanent magnet contains M in such a range that the ratio (atomic %) of T to M is (1-y):y. Each element in M ​​is ThMn 12 By containing M within the above range, the decrease in saturation magnetization is suppressed while the crystalline structure of ThMn is stabilized. 12 The stability of the crystalline structure is improved. From the viewpoint of crystal structure stability, y should be 0.01 or more, and preferably 0.02 or more. On the other hand, from the viewpoint of suppressing a decrease in saturation magnetization, y should be 0.5 or less, and preferably 0.1 or less.

[0028] The total content ratio (b) of T and M in the entire permanent magnet can be expressed as 100-(a+c), where ThMn 12 In order to have the type crystal structure as the main phase, b is 70 to 94. In order to increase the magnetization, b is preferably 75 or more, and more preferably 77 or more.

[0029] The permanent magnet also contains 0.1 to 20 atomic percent of B (boron). By containing 0.1 atomic percent or more (0.1≦c), the precipitation of α-iron (ferrite phase) is suppressed during cooling in the production of the permanent magnet, improving coercivity (Hcj). From the viewpoint of suppressing the precipitation of α-iron, the B content (c) is preferably 0.5 or more. Furthermore, by setting the B content (c) to 1 or more, preferably by using the manufacturing method described below, it is estimated that an amorphous phase is formed at the crystal grain boundaries. This amorphous phase serves as a domain wall pinning site, increasing the coercivity of the permanent magnet. In order to form an amorphous phase and further increase the coercivity, the B content (c) is preferably 1.2 or more, more preferably 1.5 or more. On the other hand, in order to prevent a decrease in saturation magnetization, the B content (c) is preferably 15 or less, more preferably 10 or less.

[0030] The present permanent magnet may contain inevitable impurities as long as the effects of the present invention are achieved. Inevitable impurities are elements that are inevitably mixed in from raw materials or during the manufacturing process and are not included in formula (1) (elements other than R, T, M, Zr, and B). Specific examples include, but are not limited to, O, C, N, P, S, and Sn. The proportion of inevitable impurities in the present permanent magnet is preferably 5 atomic % or less, more preferably 1 atomic % or less, and even more preferably 0.1 atomic % or less, based on the total amount of the permanent magnet.

[0031] The content of each element in the permanent magnet can be measured, for example, by using energy dispersive X-ray spectrometry (EDX).

[0032] This permanent magnet satisfies the composition of formula (1) above, and is therefore ThMn 12 The permanent magnet has crystal grains made up of a main phase having a crystal structure of the ThMn type, and crystal grain boundaries that are the boundaries between the crystal grains. 12 It has excellent crystal structure stability, saturation magnetization, coercive force, and heat resistance. In particular, it is preferable to concentrate B (boron) on the grain boundary side of this permanent magnet using the manufacturing method described below. For example, in this permanent magnet, the proportion (atomic %) of B element on the grain boundary can be made 10 times or more the proportion of B element in the crystal grains. This further improves the coercive force. The permanent magnet has a coercive force (Hcj) of, for example, 1.8 kOe or more, preferably 2.0 or more, and a Curie temperature of, for example, 400°C or more. The grain boundary structure can be observed using a scanning transmission electron microscope (STEM). The Curie temperature can be measured using a vibrating sample magnetometer (VSM). The coercive force can be determined from the JH curve obtained using a DC magnetization analyzer.

[0033] [Manufacturing method for rare earth cobalt permanent magnets] The method for manufacturing a permanent magnet according to this embodiment (hereinafter also referred to as the present manufacturing method) is as follows: a step (I) of preparing a molten metal having a composition represented by the formula (1); The molten metal was added to the 2 ~10 7 Step (II) of rapidly cooling the mixture at 1000 K / sec to form an alloy; (III) a step of pulverizing the alloy to form a powder; Step (IV) of molding the powder into a molded body; a step (V) of sintering the compact to form a sintered body; and step (VI) of heat-treating the sintered body and then quenching it.

[0034] This manufacturing method allows the production of ThMn 12 The permanent magnet can be suitably produced having crystal grains made up of a main phase having a crystal structure of this type and crystal grain boundaries that are the boundaries between the crystal grains, with the crystal grain boundaries having an amorphous phase.

[0035] First, a molten metal having a composition represented by formula (1) is prepared (step (I)). The molten metal may be prepared by purchasing a commercially available alloy having the desired composition, or by blending the elements to obtain the desired composition. If there is a possibility that the elements may evaporate in a later process, the composition after the permanent magnet is manufactured is adjusted so that it satisfies formula (1). The prepared alloy is melted to obtain a molten metal. The melting method may be appropriately selected from known melting means such as arc melting and high-frequency melting.

[0036] Next, the molten metal was 2 ~10 7 The mixture is then rapidly cooled at 10 K / sec (Step (II)). 2 By rapidly cooling the molten metal at a cooling rate of 10 K / sec or more, it is possible to obtain an alloy in which the precipitation of α-Fe (α iron) is suppressed. By suppressing the precipitation of α-Fe, an amorphous phase can be favorably formed at the grain boundaries, and a permanent magnet with high coercive force can be obtained. The alloy after rapid cooling may be further heat-treated to homogenize the structure. The rapid cooling rate is particularly preferred at 10 3 ~10 6 K / sec is preferred. Furthermore, in order to suppress the precipitation of α-iron due to rapid cooling, it is preferable that the alloy be formed into flakes. The thickness of the flakes is preferably 1 to 100 μm, more preferably 20 to 90 μm, in order to facilitate rapid cooling. Note that the viscosity of the alloy is reduced by including boron, and therefore flakes of the above thickness are easily obtained when the molten metal is rapidly cooled by a melt-spun method or the like.

[0037] The amount of α-iron can be evaluated, for example, by X-ray diffraction spectroscopy. Specifically, the X-ray diffraction spectrum of the permanent magnet is measured using Cu Kα characteristic X-rays, and the amount of α-iron in the main phase, ThMn 12 The peak intensity (I ThMn12 ) and the peak intensity of the peak corresponding to the 110 plane of α-iron (I α-Fe ) intensity ratio (I α-Fe / I ThMn12 ) the degree of α-iron precipitation can be estimated. The peak intensity is the peak height minus the background, and the intensity ratio is preferably 1.0 or less, more preferably 0.8 or less. The lower the intensity ratio, the better. There is no particular lower limit, but it is usually 0.001 or more.

[0038] Next, the alloy is pulverized (step (III)). The method for pulverizing the alloy may be appropriately selected from conventionally known methods. As an example, the alloy is first coarsely pulverized in an inert atmosphere using a known pulverizer such as a disk mill. If pulverization is poor, the alloy may be subjected to a hydrogen absorption treatment beforehand. The hydrogen absorption treatment embrittles the alloy, making it easier to coarsely pulverize. Next, the coarsely pulverized material is further pulverized. The pulverization may be dry pulverization or wet pulverization. Examples of dry pulverization include a jet mill method. Examples of wet pulverization include a wet ball mill method. A lubricant may be added to impart lubricity to the powder during pulverization. The mixture of the organic solvent and the fine powder after pulverization is dried in an inert gas. The average particle size of the powder after pulverization is preferably 1 to 10 μm, which enables the sintering time in the sintering step described below to be shortened and also allows for the production of uniform permanent magnets.

[0039] Next, the obtained powder is pressure-molded to form a compact of the desired shape (step (IV)). In the present invention, pressure molding is preferably performed in a constant magnetic field in order to align the crystal orientation of the powder and improve magnetic properties. The relationship between the direction of the magnetic field and the pressing direction is not particularly limited and may be selected appropriately depending on the shape of the product, etc. For example, when manufacturing a ring magnet or a thin plate magnet, parallel magnetic field pressing can be used, in which a magnetic field is applied parallel to the pressing direction. On the other hand, perpendicular magnetic field pressing, in which a magnetic field is applied perpendicular to the pressing direction, is preferred in order to achieve excellent magnetic properties.

[0040] The strength of the magnetic field is not particularly limited, and may be, for example, 15 kOe or less or 15 kOe or more depending on the application of the product. In particular, from the viewpoint of excellent magnetic properties, it is preferable to perform pressure molding in a magnetic field of 15 kOe or more. The pressure during pressure molding may be adjusted appropriately depending on the size, shape, etc. of the product. For example, it may be 0.5 to 2.0 ton / cm. 2 That is, in the method for producing a permanent magnet of the present invention, from the viewpoint of magnetic properties, the powder is subjected to a magnetic field of 15 kOe or more and a pressure of 0.5 to 2.0 ton / cm perpendicular to the magnetic field. 2It is particularly preferable to carry out the pressing at the following pressures:

[0041] Next, the green body is sintered to form a sintered body (step (V)). The sintering temperature is preferably 950 to 1250°C, more preferably 950 to 1220°C. The sintering time is preferably 20 to 240 minutes, more preferably 60 to 120 minutes. By sintering at 950°C or higher for 20 minutes or longer, the sintered body is sufficiently densified. By heating at 1250°C or lower for 240 minutes or shorter, evaporation of rare earth elements, particularly Sm, is suppressed. From the viewpoint of suppressing oxidation, the sintering step is preferably carried out in a vacuum of 1000 Pa or less or in an inert gas atmosphere. Furthermore, from the viewpoint of increasing the density of the sintered body, it is preferable to sinter in a vacuum of 1000 Pa or less, preferably 100 Pa or less.

[0042] After the step (V), the obtained sintered body is preferably subjected to a heat treatment. 12 The heat treatment temperature is preferably 500 to 1180°C, more preferably 500 to 900°C. Heat treatment at 500°C or higher results in uniform structure and the formation of a ThMn 12 This promotes the formation of the mold structure and makes it easier to obtain the liquid phase component. On the other hand, by performing the heat treatment at 1180°C or less, the liquid phase component is prevented from becoming too much, thereby suppressing deterioration of the magnetic properties. The heat treatment time can be, for example, 1 to 100 hours, preferably 5 to 50 hours.

[0043] Next, the heat-treated sintered body is rapidly cooled (step (VI)). Rapid cooling forms an amorphous phase at the grain boundaries. The rapid cooling rate in step (VI) may be 60 to 250°C / min, and preferably 100 to 250°C / min.

[0044] The obtained sintered body may be further subjected to aging treatment as required. 12The present permanent magnet can be manufactured having crystal grains made up of a main phase having a crystal structure of this type, and crystal grain boundaries that are the boundaries between the crystal grains, with the crystal grain boundaries having an amorphous phase.

[0045] [device] The present invention can also provide a device having the permanent magnet. Specific examples of such devices include watches, electric motors, various meters, communication devices, computer terminals, speakers, video disks, and sensors. Furthermore, because the magnetic force of the permanent magnet of the present invention is resistant to deterioration even at high environmental temperatures, it can also be suitably used in angle sensors used in automobile engine compartments, ignition coils, drive motors for HEVs (hybrid electric vehicles), and the like. [Example]

[0046] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these descriptions.

[0047] Example 1 Each metal was weighed in a predetermined amount to obtain the composition shown in Table 1, and a master alloy was obtained by high-frequency melting. The master alloy was then high-frequency melted again and melted by the melt-spun method. 2 ~10 7 The alloy flakes were then rapidly cooled at 1000°C / sec to obtain alloy flakes with the thicknesses shown in Table 1. They were then coarsely pulverized in a vibration mill and finely pulverized in a wet ball mill to obtain raw material powder. These were then molded into a powder compact by pressing in a magnetic field. The powder compact was sintered and subsequently subjected to heat treatment. The sintering temperature was 1000°C, and the heat treatment temperature was 900°C. After heat treatment, the permanent magnet of Example 1 was obtained by rapidly cooling.

[0048] (Examples 2 and 3) Permanent magnets of Examples 2 and 3 were obtained in the same manner as in Example 1, except that the composition and heat treatment temperature in Example 1 were changed as shown in Table 1.

[0049] (Comparative Examples 1 to 3) Permanent magnets of Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the composition, flake thickness, and heat treatment temperature were changed as shown in Table 1.

[0050] [evaluation] The X-ray diffraction spectra of the permanent magnets of the above examples and comparative examples were measured. The results are shown in Figure 1. The X-ray diffraction spectra in Figure 1 also show that ThMn 12 The peak intensity (I ThMn12 ) and the peak intensity of the peak corresponding to the 110 plane of α-iron (I α-Fe The results are shown in Table 1. Furthermore, the JH curve of each permanent magnet was measured using a DC magnetization characteristic analyzer to obtain the coercive force Hcj. The results are shown in Table 1.

[0051] [Table 1]

[0052] As shown in Table 1, the permanent magnets of Examples 1 to 3 containing 0.1 atomic % or more of boron showed suppressed precipitation of α-iron and excellent coercive force.

[0053] (Examples 4 to 5) Each metal was weighed in a predetermined amount so as to obtain the composition shown in Table 2, and the metal was melted in a high-frequency melting and quenched ribbon manufacturing device for 10 minutes. 2 ~10 7The raw material alloy was prepared by quenching at 1000 K / sec. This alloy was heat-treated at 800 to 1180°C to homogenize the composition. The alloy was then heated in a hydrogen atmosphere at 200 to 600°C to absorb hydrogen. The alloy was then coarsely pulverized using a disk mill and finely pulverized using a ball mill in 2-propanol solvent. A lubricant was added during the fine pulverization process. This imparted lubricity to the powder, facilitating magnetic field orientation in the subsequent compacting process. A slurry consisting of the solvent, lubricant, and fine powder was pressurized and dried using nitrogen gas, and the resulting raw material powder was compacted in a magnetic field. The compact was heated in a hydrogen atmosphere and subjected to a decarbonization heat treatment. The atmosphere was then switched to a vacuum and the temperature was increased, sintered at 1200°C in an Ar atmosphere at 30 kPa, and further heat-treated at 800 to 1180°C. Finally, the sintered body was rapidly cooled to obtain the permanent magnets of Examples 4 and 5.

[0054] Comparative Example 4 In the above Examples 4 and 5, except that the composition was changed as shown in Table 2, the same procedures as in Examples 4 and 5 were carried out to prepare the comparative examples. 4 A permanent magnet of 1000 .mu.m was obtained.

[0055] [evaluation] The JH curve of each permanent magnet was measured using a DC magnetization characteristic analyzer to obtain the saturation magnetization (4πIs) and coercive force Hcj. The results are shown in Table 2.

[0056] [Table 2]

[0057] As shown in Table 2, the permanent magnets of Examples 4 and 5, which satisfy the composition of formula (1), exhibited excellent coercive force while maintaining high saturation magnetization. When the structures of the permanent magnets of Examples 4 and 5 were observed using a scanning transmission electron microscope (STEM), it was found that the magnets were composed of ThMn 12Crystal grains having a crystalline structure of this type and crystal grain boundaries containing an amorphous phase were confirmed. Furthermore, it was confirmed that the B element was concentrated in the amorphous phase (crystal grain boundaries) in the permanent magnets of Examples 4 and 5, with an atomic percent concentration of B element in the crystal grains that was 10 times or more higher. On the other hand, the permanent magnet of Comparative Example 4, which did not contain B, did not have an amorphous phase in the crystal grain boundaries.

[0058] This application claims priority based on Japanese Patent Application No. 2020-203239, filed on December 8, 2020, the disclosure of which is incorporated herein in its entirety.

Claims

1. A permanent magnet having a composition represented by the following formula (1), comprising crystal grains made of a main phase having a ThMn 12 -type crystal structure, and crystal grain boundaries, the crystal grain boundaries including an amorphous phase: Formula (1): (R １－ｘ Zr ｘ ) ａ (T １－ｙ M ｙ ) ｂ B ｃ However, in formula (1), R is at least one selected from rare earth elements, T is at least one selected from the group consisting of Fe, Co, and Ni; M represents at least one selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W; a, b, and c each represent atomic %, x and y each represent the ratio of Zr and M, and are numbers that satisfy the following formula: 5≦a≦12, b=100-(a+c), 0.1≦c≦20, 0.01≦x≦0.5, 0.01≦y≦0.

5.

2. A permanent magnet as described in claim 1, wherein the proportion (atomic %) of B element in the crystal grain boundary is 10 times or more the proportion of B element in the crystal grain.

3. A permanent magnet as described in claim 1 or 2, wherein the intensity ratio (I α-Fe / I ThMn12 ) of the peak intensity (I ThMn12 ) corresponding to the 321 plane of the ThMn 12 type crystal structure to the peak intensity (I α-Fe ) corresponding to the 110 plane of α-iron in an X-ray diffraction spectrum is 1.0 or less.

4. A permanent magnet having a composition represented by the following formula (1), in which the intensity ratio (I α-Fe / I ThMn12 ) of the peak intensity (I ThMn12 ) corresponding to the 321 plane of a ThMn 12 type crystal structure to the peak intensity (I α-Fe ) corresponding to the 110 plane of α-iron in an X-ray diffraction spectrum is 1.0 or less. Formula (1): (R １－ｘ Zr ｘ ) ａ (T １－ｙ M ｙ ) ｂ B ｃ However, in formula (1), R is at least one selected from rare earth elements, T is at least one selected from the group consisting of Fe, Co, and Ni; M represents at least one selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W; a, b, and c each represent atomic %, x and y each represent the ratio of Zr and M, and are numbers that satisfy the following formula: 5≦a≦12, b=100-(a+c), 0.1≦c≦20, 0.01≦x≦0.5, 0.01≦y≦0.

5.

5. The permanent magnet according to any one of claims 1 to 4, wherein 50 atomic % or more of the R is Sm.

6. The permanent magnet according to any one of claims 1 to 5, wherein 50 atomic % or more of the T is Fe.

7. The permanent magnet according to any one of claims 1 to 6, wherein a is a number satisfying 5≦a≦8.

8. The permanent magnet according to any one of claims 1 to 7, having a coercive force (Hcj) of 1.8 kOe or more.

9. The permanent magnet according to any one of claims 1 to 8, having a Curie temperature of more than 400°C.

10. A step (I) of preparing a molten metal having a composition represented by the following formula (1); The molten metal was ２ ~10 ７ Step (II) of quenching at 1000 K / sec to form an alloy; (III) grinding the alloy into a powder; Step (IV) of molding the powder into a molded body; a step (V) of sintering the compact to form a sintered body; and (VI) heat-treating the sintered body and then quenching it. How permanent magnets are manufactured. Formula (1): (R １－ｘ Zr ｘ ) ａ (T １－ｙ M ｙ ) ｂ B ｃ However, in formula (1), R is at least one selected from rare earth elements, T is at least one selected from the group consisting of Fe, Co, and Ni; M represents at least one selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Hf, Nb, Mo, Ta, and W; a, b, and c each represent atomic %, x and y each represent the ratio of Zr and M, and are numbers that satisfy the following formula: 5≦a≦12, b=100-(a+c), 0.1≦c≦20, 0.01≦x≦0.5, 0.01≦y≦0.

5.

11. A device comprising a permanent magnet according to any one of claims 1 to 9.

Images