WO2017170129A1

WO2017170129A1 - Permanent magnet manufacturing method

Info

Publication number: WO2017170129A1
Application number: PCT/JP2017/011742
Authority: WO
Inventors: 泰直三浦; 入江　周一郎
Original assignee: Tdk株式会社
Priority date: 2016-03-28
Filing date: 2017-03-23
Publication date: 2017-10-05

Abstract

The present invention provides a method for manufacturing a permanent magnet, said method characterized in comprising a preforming step for obtaining a preform by pressurizing a magnetic powder containing MnBi in a magnetic field; a heating step for heating the preform using at least one method selected from infrared heating, microwave heating, and high frequency induction heating; and a molding step for obtaining a compact by pressurizing the heated preform. According to the present invention, it is possible to increase the adhesion between magnetic powder particles by fabricating the preform made in the preforming step by pressurizing the magnetic powder containing MnBi in a magnetic field. The thermal conduction is thereby improved, and it is therefore possible to quickly raise the temperature to the desired temperature in the heating step. As a result, it is possible to obtain a permanent magnet having high magnetic characteristics.

Description

Method for manufacturing permanent magnet

The present invention relates to a method for manufacturing a permanent magnet.

Among rare earth magnets, neodymium (Nd—Fe—B) magnets are known as the most powerful permanent magnets. Such permanent magnets using rare earth elements are used in various fields such as audio / video equipment, rotating equipment, communication equipment, measuring equipment, automobile parts, etc. As the demand increases, in addition to improving magnetic properties, industrial production However, since rare earth elements are expensive, permanent magnets that do not use rare earth elements are desired.

MnBi is known as a magnetic material that does not use rare earth elements. MnBi exhibits a strong magnetic anisotropy and has the property that the magnetic anisotropy increases with increasing temperature. In particular, it is known to have a very high coercive force at a high temperature of 200 ° C. or higher.

As a conventional method for producing a MnBi magnet, there is known a method for producing a high-purity MnBi magnet by sintering a compact obtained by mixing Mn powder and Bi powder in a magnetic field (Patent Document 1). However, the manufacturing method as described in Patent Document 1 cannot obtain a MnBi magnet having sufficiently high magnetic properties.
Another method for producing MnBi magnets is to make Mn-Bi alloy produced by arc melting or high frequency melting amorphous by liquid quenching method, crystallized by heat treatment, and filled with MnBi powder anisotropicized by grinding. In addition, there is a method of manufacturing a MnBi magnet by applying pressure in a magnetic field.
In addition, in the method of producing an MnBi magnet by applying pressure in a magnetic field, it is necessary to heat the MnBi powder. However, when the MnBi powder is heated, the MnBi powder is oxidized, and a decrease in magnetic properties cannot be avoided. In a method in which MnBi powder is filled in a mold and MnBi is heated using the mold as a heating medium, heating takes time, and the magnetic powder is oxidized, leading to a decrease in magnetic properties.

JP2015-63725

An object of the present invention is to provide a manufacturing method capable of solving the above-described problems in the prior art and manufacturing a permanent magnet having excellent magnetic properties.

In order to achieve the above object, a method for producing a permanent magnet according to the present invention includes a temporary molding step of pressing a magnetic powder containing MnBi in a magnetic field to obtain a temporary molded body, infrared heating and microwave heating of the temporary molded body A heating step of heating to a predetermined temperature by at least one method selected from high-frequency induction heating, and a molding step of pressing the temporary molded body heated to the predetermined temperature to obtain a molded body And

According to the present invention, the magnetic powder containing MnBi is pressed in a magnetic field in the temporary molding step to produce a temporary molded body, thereby improving the adhesion between the magnetic powders. Thereby, since heat conduction improves, it can be heated up quickly to a desired temperature in a heating process. As a result, it is possible to produce a permanent magnet that not only suppresses deterioration of magnetic properties due to oxidation but also has low density unevenness. Moreover, since the area where the magnetic powder comes into contact with the atmosphere can be reduced by preparing the temporary molded body, it is possible to suppress a decrease in magnetic characteristics due to oxidation. Further, since the temporary molded body is heated by at least one heating method selected from infrared heating, microwave heating, and high frequency induction heating in the heating step, the temporary molded body can be heated uniformly in a short time, and magnetic characteristics High permanent magnets can be obtained.

In addition to MnBi, the magnetic powder containing MnBi preferably contains one or more kinds of magnetic powder selected from Sm—Fe—N, Nd—Fe—B, and Sm—Co. Sm—Fe—N, Nd—Fe—B, and Sm—Co based magnetic materials produce powders with high magnetic properties. By including these magnetic powders, permanent magnets with high magnetic properties are produced. be able to.

It is preferable that the temporary molded body contains a metal binder. In the molding process, the metal binder heated to the melting point or higher melts, the filling rate of the magnetic powder is improved, and a permanent magnet having high magnetic properties can be produced.

According to the present invention, it is possible to provide a method for manufacturing a permanent magnet having high magnetic properties.

It is a schematic diagram which shows the suitable shaping | molding apparatus in a magnetic field in the manufacturing method of the permanent magnet of this invention. It is a schematic diagram which shows the suitable heating apparatus in the manufacturing method of the permanent magnet of this invention.

The manufacturing method of the permanent magnet of the present invention will be described for each of the following steps.

(1) Preparation of magnetic powder In this invention, the magnetic powder containing MnBi is used. MnBi includes an LTP phase, a QHTP phase, an HTP phase, and the like, and is preferably an LTP phase having a large magnetic anisotropy. The magnetic powder may contain a magnetic material other than MnBi. In particular, a permanent magnet having high magnetic properties can be obtained by mixing magnetic materials having high magnetic properties such as rare earth alloys such as Sm—Fe—N, Nd—Fe—B, and Sm—Co. One of these magnetic materials may be used, or two or more of them may be included. The magnetic powder used in the present invention is preferably an anisotropic magnet powder. Anisotropic magnet powder can align the magnetization direction by applying a magnetic field, and can produce a permanent magnet with strong magnetic force.

The particle size of the magnetic powder can be applied in a wide range, but the average particle size is preferably 0.5 μm or more and 200 μm or less. When the average particle size is 0.5 μm or more, oxidation is suppressed and productivity is improved. When the average particle size is 200 μm or less, the number of contacts between the particles increases, and the heating time can be shortened, so that productivity is improved.

Further, it is preferable that the temporary molded body contains a metal binder. By adding a low melting point metal binder, a permanent magnet having high density and high magnetic properties can be obtained. The metal binder is not particularly limited, but one or more selected from copper, cobalt, tin, phosphorus, zinc, silver, nickel, iron, aluminum, molybdenum, chromium, titanium, manganese, gallium, bismuth and tungsten. Metals or their alloys can be used. The metal binder is preferably a low melting point metal at 150 ° C to 300 ° C. A diffusion phase is formed at the interface between the magnetic powder of the permanent magnet and the metal binder. It is preferable that the metal binder has a low melting point and is molded at a low temperature because surface diffusion of the metal binder to the magnetic powder can be suppressed and high magnetic properties can be obtained.

When mixing MnBi with Sm—Fe—N, Nd—Fe—B, or Sm—Co based magnetic powder, or when mixing magnetic powder and metal binder, attritor, Henschel mixer or V-type mixer, etc. To obtain a mixture. In order to uniformly mix the metal binder, it is preferable to use an organic solvent or the like. It is also preferable to granulate the mixture.

The mixing ratio of the magnetic powder and the metal binder is preferably 1 to 15 wt% of the metal binder with respect to 85 to 99 wt% of the magnetic powder. By setting the amount of magnetic powder to 85 wt% or more and the amount of metal binder to 15 wt% or less, high magnetic properties can be obtained. On the other hand, a permanent magnet having high strength can be obtained by setting the amount of magnetic powder to 99 wt% or less and the amount of metal binder to 1% or more.

Additives other than metal binders may be used as necessary. Although the kind of additive is not particularly limited, a surfactant, a coupling agent, a lubricant, a release agent, a flame retardant, a stabilizer, an inorganic filler, a pigment, and the like can be used. This additive provides fluidity to fill the mold, slipperiness to align the magnetization direction by applying a magnetic field, releasability when taking out from the mold, water repellency, density improvement or strength improvement of the molded body. As long as it is shown, a plurality of types of additives may be used in combination.

(2) Temporary molding step In this embodiment, the magnetic powder or a mixture of magnetic powder and a metal binder is filled in a mold, a magnetic field is applied, a temporary molding pressure is applied, and a temporary molded body is obtained. In the process, the temperature can be quickly raised to a desired temperature, and not only the deterioration of magnetic properties due to oxidation can be suppressed, but also a permanent magnet having a high density can be produced. In addition, since the area where the magnetic powder comes into contact with the atmosphere is reduced, a decrease in magnetic properties due to oxidation in the heating process can be suppressed.

In order to obtain a high degree of orientation, it is necessary to apply a strong magnetic field, and the strength of the magnetic field must be 10 kOe or more regardless of whether a static magnetic field is applied or a pulse system in which a magnetic field is applied discontinuously. preferable. The magnetic field orientation direction may be a direction parallel to or perpendicular to the pressing direction. Longitudinal magnetic field shaping with the magnetic field parallel to the pressing direction is effective when a cylindrical shaped body is oriented in the axial direction, and transverse magnetic field shaping with the magnetic field perpendicular to the pressing direction. Is effective when orienting a cube or a rectangular parallelepiped, or when orienting a ring magnet axially (uniaxial direction). The molding pressure in the temporary molding step is preferably 50 MPa or more, more preferably 100 MPa or more, further preferably 300 MPa or more, or the mold temperature is preferably 150 ° C. or less, more preferably 100 ° C. or less, more preferably 60 ° C. or less, Particularly preferably, by setting the temperature to 23 ° C. or less, the relative density of the temporary molded body can be increased, and the temporary molded body can be heated more uniformly and quickly in the heating step. Furthermore, it is possible to suppress damage to the temporary molded body in the heating process and the molding process and to suppress a decrease in orientation during pressurization in the molding process. In consideration of the durability of the mold, the molding pressure in the temporary molding process is preferably 1000 MPa or less.

FIG. 1 shows an embodiment of a forming apparatus in a magnetic field in the method for producing a permanent magnet according to the present embodiment. The forming apparatus 1 in a magnetic field has an electromagnet 2 and an upper punch 4a at the upper and lower parts in the drawing. It has a structure having a pressure device 3 having a lower punch 4b and a die 4c having a heating device 4d. It is preferable to reduce the residual magnetic flux density in the temporary molded body by subjecting the temporary molded body to AC demagnetization. During AC demagnetization, it is preferable to raise the temperature of the mold to a predetermined temperature because the residual magnetization becomes smaller.

(3) Heating step In the present embodiment, the temporary molded body is heated using at least one heating method selected from infrared heating, microwave heating, and high frequency induction heating. Since the mixture can be heated uniformly in a short time, a permanent magnet with high magnetic properties can be obtained.

When using infrared heating as the heating method, it is preferable to use infrared rays having a wavelength peak of 0.70 to 3.0 μm. When the wavelength peak is shorter than 0.70 μm, it becomes close to visible light. By shortening the wavelength peak to less than 3.0 μm, the heating rate is increased, and by shortening the heating time of the mixture, the oxidation of the magnetic powder is suppressed and the deterioration of the magnetic properties can be reduced. When microwave heating is used as the heating method, the microwave is preferably 0.5 to 50 GHz or less. Generation | occurrence | production of arc discharge can be suppressed and a mixture can be heated up in a desired temperature range. When high frequency induction heating is used as the heating method, the frequency is preferably 1 to 30 MHz. In this way, the magnetic powder and the metal binder are selectively and rapidly self-heated to 150 ° C. to 350 ° C., preferably 250 ° C. to 300 ° C., several tens of seconds to several minutes, preferably 1 to 3 minutes. Raise the temperature.

At this time, a high-density permanent magnet can be obtained by uniformly raising the temperature of the entire mixture. In addition, since the temperature can be raised to a predetermined temperature in a short time, the processing time can be shortened and oxidation of the magnetic powder can be suppressed.

When heating, it may be preferable to use auxiliary heating means such as atmospheric convection heating in some cases, and by using such a heating method, heating with more uniform heating efficiency can be performed. Can do.

FIG. 2 shows an embodiment of a heating device in the method of manufacturing a permanent magnet according to the present embodiment. The heating device 5 includes a metal furnace wall 7a including a heat insulating material or a heat insulating layer. In addition, a circulating atmosphere outlet 6a and a circulating atmosphere inlet 6b are provided on the upper side in the figure, a heated product inlet 7b is provided on the right side in the figure, and a heated article discharge port 7c is provided on the left side in the figure. A furnace body 7 that is 7d, a belt conveyor 10 that conveys a tray 9 on which a temporary molded body is placed, and a plurality of infrared heating sources (infrared lamps) or microwave heating sources 8 provided above the belt conveyor 10 The coil 11a and the coil 11b are arranged on the upper and lower surfaces of the temporary molded body 9 to form a structure. By passing an alternating current having a desired frequency through the

coils

11a and 11b, the temporary molded body is induction-heated.

In the case of infrared heating or microwave heating, the temporary molded body in the mold cavity may be directly irradiated without using the heating device as shown in FIG. In the case of high-frequency heating, the mold and the temporary molded body may be heated at the same time while the temporary molded body is filled in the mold. Thus, pressurization may be performed while heating in the mold cavity.

The temporary molded body conveyed on the belt conveyor is heated by at least one method selected from infrared heating, microwave heating, and high-frequency induction heating, and evenly by the heated circulating atmosphere ejected from the circulating atmosphere ejection outlet It will be heated. Since the heating time is as short as about 0.5 to 3 minutes, oxidation of the magnetic powder is suppressed and a permanent magnet having excellent magnetic properties can be obtained.

(4) Molding process The molding process of the present invention is a process in which a temporary molded body heated to a predetermined temperature in the heating process is filled in a mold and pressed to obtain a permanent magnet. A high density permanent magnet can be obtained by pressurizing at a high molding pressure of 10 MPa or more. A high-density permanent magnet can be obtained by pressing at a molding pressure of preferably 50 MPa or more, more preferably 100 MPa or more, and even more preferably 500 MPa or more. In consideration of the durability of the mold, it is preferable to pressurize at a pressure of 1500 MPa or less. In the molding step, heating is preferable because the density of the permanent magnet is increased and a permanent magnet having high magnetic properties can be obtained. The molding temperature is preferably lower than the decomposition temperature 355 ° C. of MnBi, more preferably 250 ° C. to 300 ° C. When the temporary molded body includes a metal binder, the molding temperature is preferably equal to or higher than the melting point of the metal binder.

The temporary forming step, heating step, and forming step are preferably performed in an inert gas atmosphere to prevent oxidation of the magnetic powder.

∙ Surface treatment such as painting or plating is applied to the obtained permanent magnets as necessary.

Hereinafter, the effect of the present invention is illustrated by examples. The magnetic powder used in Examples and Comparative Examples was obtained by the following method.

(MnBi anisotropic magnet powder)
A specified amount of Mn having a purity of 99.9% and Bi having a purity of 99.9% were respectively weighed with an electronic balance, and an ingot was produced by arc melting. The produced ingot was melted using high frequency melting in an Ar atmosphere, and a MnBi ribbon was produced by a liquid quenching method. The obtained ribbon was heated in an Ar atmosphere at 300 ° C. for 12 hours. Then, it grind | pulverized for 20 hours with the ball mill, and obtained the anisotropic magnet powder whose average particle diameter is 5 micrometers.

(Sm ₂ Fe ₁₇ N ₃ anisotropic magnet powder)
Sm ₂ Fe ₁₇ N ₃ powder manufactured by Sumitomo Metal Mining was used. The average particle size is 5 μm.

(Nd ₂ Fe ₁₄ B anisotropic magnet powder)
An Nd—Fe—B alloy having an atomic fraction of 13% Nd, 12% Co, 1% Ga, 6% B, and the balance Fe is held in hydrogen gas at 700 to 900 ° C. Decomposed into hydride, Fe ₂ B, and Fe. Next, the hydrogen pressure was lowered in this temperature region to dissociate hydrogen from the Nd hydride, thereby obtaining a fine magnetic powder of Nd ₂ Fe ₁₄ B crystal. The obtained magnetic powder was further mechanically pulverized to obtain anisotropic magnet powder having an average particle size of 150 μm.

(Sm ₂ Co ₁₇ anisotropic magnet powder)
Sm ₂ Co _17- based intermetallic compound alloy represented by Sm (Co _0.59 Cu _0.07 Fe _0.22 Zr _0.02 ) _8.3 was melted and cast, and this was cast in an argon gas atmosphere furnace After heating at 1160 ° C for 4 hours, precipitation hardening was performed by rapidly cooling to 200 ° C at a rate of 35 ° C per minute. The ingot cooled to room temperature was aged by two-stage heating at 800 ° C. for 2 hours and 740 ° C. for 3 hours in an argon gas atmosphere furnace, and cooled to room temperature at a rate of 65 ° C. per minute. Thereafter, the ingot was mechanically pulverized to obtain anisotropic magnet powder having an average particle size of 50 μm.

The metal binder used in the examples and comparative examples was obtained as follows.

(Bi powder and Sn powder)
Bi powder (purity: 3N, particle size: 30 μm) and Sn powder (purity: 3N, particle size: 60 μm) were both made of high-purity chemicals.

(Bi-Sn alloy powder)
Bi (product made from high purity chemical, purity: 3N, particle size: 2 to 3 mm) and Sn (product made from high purity chemical, purity: 3N, particle size: 2 to 3 mm) are weighed to 58:42 wt% and mixed. The ingot obtained by melting was mechanically pulverized to obtain a 130 μm alloy powder.

(Production of mixture)
MnBi and Sm—Fe—N, Nd—Fe—B, and Sm—Co anisotropic magnet powders and metal binders were weighed using an electronic balance at the weight ratios shown in Table 1, respectively, in an Ar atmosphere. Dispersion mixing was performed for 1 hour using a V-type mixer to prepare a mixture.

(Preparation of temporary molded body)
The mixture obtained by the above method was filled in a mold, and a mold temperature shown in Table 2, an applied magnetic field, and a molding pressure were applied to obtain a temporary molded body. Thereafter, the temporary molded body was demagnetized by AC demagnetization.

(Preparation of permanent magnet)
The temporary molded body obtained by the above method was heated using the heating apparatus shown in FIG. 2 under the heating conditions shown in Table 3, and the temporary molded body was filled in a mold. A 10 mm square cubic permanent magnet sample was prepared by applying the mold temperature, applied magnetic field and molding pressure shown in Table 2. The holding time of the molding pressure was 1 minute.

With respect to the obtained permanent magnet sample, (1) magnetic properties and (2) relative density were measured by the following methods. Table 4 shows the measurement results.
(1) Magnetic characteristics Using the obtained 10 mm cubic sample, residual magnetization (Br), saturation magnetization (4πMs), and maximum energy product (BH) max were measured with a BH tracer (manufactured by Tamagawa Seisakusho, maximum magnetic field: 30 kOe). The degree of orientation Br / 4πMs was calculated. The volume ratio of each magnetic powder was calculated using the weight ratio of the magnetic powder and the metal binder described in Table 1 and the specific gravity of the magnetic powder and the metal binder described in Tables 5 and 6. The specific gravity of the magnetic powder and the metal binder was measured using a pycnometer method. (BH) max and Br of the magnetic powder were measured with a vibrating sample magnetometer (VSM) after orientation of the magnetic powder was performed in a magnetic field of 10 kOe, and the magnetic powder was fixed to paraffin. A value calculated as the sum of products of (BH) max and volume ratio of each magnetic powder is defined as a theoretical maximum (BH) max. When heating the powder mixture without producing a temporary molded body, or when heating is not performed by at least one method selected from infrared heating, microwave heating, and high frequency induction heating, (BH) max is 50% or less of the theoretical maximum (BH) max. When the (BH) max of the sample manufactured in this example was 55% or more of the theoretical maximum (BH) max, it was judged that good magnetic properties were obtained.
(2) Relative density The measured density was calculated by measuring the weight and volume of the obtained sample. The calculated density of the mixed powder was calculated from the specific gravity described in Tables 5 and 6 and the weight ratio in Table 1, and the relative density was calculated by dividing the measured density by the calculated density.

According to the present invention, by preparing a temporary molded body in the temporary molding process, the heat conduction of the magnetic powder is improved and the heating process is uniformly and quickly heated, so that deterioration of magnetic properties due to oxidation can be suppressed. Permanent magnets with high magnetic properties were produced. In the heating step, the mixture was heated by at least one heating method selected from infrared heating, microwave heating, and high frequency induction heating, so that the temperature of the mixture could be increased uniformly in a short time. As a result, the magnetic powder could be heated uniformly in a short time, and a permanent magnet excellent in density and magnetic properties could be obtained.

As can be seen from Examples 1 to 4, by increasing the mold temperature in the temporary molding step, a high-density temporary molded body is obtained, and as a result of suppressing the disorder of orientation in the molding step, the degree of orientation Br / 4πMs is further increased. A high sample could be obtained.

As can be seen from Examples 1, 5, and 6, by increasing the molding pressure in the temporary molding step, a high-density temporary molded body is obtained, and as a result of suppressing the disorder of orientation in the molding step, the degree of orientation Br / 4πMs is further increased. A high sample was obtained.

As can be seen from Examples 1, 7, and 8, since the temporary molded body was sufficiently heated in 1 minute, a sample having a high relative density and high magnetic properties could be obtained.

As can be seen from Examples 1, 9, and 10, within the range shown in Table 2, a sample having a higher relative density and a higher magnetic property could be obtained as the mold temperature in the molding process was higher.

As can be seen from Examples 1 and 11, a sample having sufficiently high magnetic properties could be obtained regardless of the presence or absence of a magnetic field in the molding process.

As can be seen from Example 1 and Examples 12 to 14, within the range shown in Table 2, the higher the molding pressure in the molding process, the higher the relative density and the higher the magnetic properties.

As can be seen from Examples 1 and 15 to 18, when the wavelength of infrared heating was changed within the range of Table 3, a sample having sufficient magnetic properties could be obtained. In particular, a sample having high magnetic properties could be obtained in the wavelength peak range of 0.75 to 2.0 μm.

As in Examples 19 to 23, when the heating method was changed to microwave heating with respect to Example 1, a sample having magnetic characteristics equivalent to those obtained when infrared heating was performed could be obtained. In particular, a sample having relatively high magnetic properties could be obtained in the frequency range of 1 to 30 MHz.

As in Examples 24 to 28, even when the heating method was changed to high frequency induction heating with respect to Example 1, a sample having magnetic characteristics equivalent to those obtained when infrared heating was performed could be obtained. In particular, a sample having relatively high magnetic properties could be obtained in the frequency range of 2 to 10 MHz.

Further, as in Examples 29 and 30, even when the heating method is changed to a combination of infrared heating and high frequency induction heating, and microwave heating and high frequency induction heating as compared to Example 1, a sample having high magnetic properties can be obtained. did it.

If the temporary molding was not performed as in Comparative Example 1, even when infrared heating was performed in the heating step, MnBi was oxidized and Br decreased, so that sufficient (BH) max could not be obtained.

When heating was performed only by atmospheric convection heating as in Comparative Example 2, it took a long time to heat and a decrease in magnetic properties due to oxidation occurred, so a sample having sufficient magnetic properties could not be obtained.

If the mixture is not heated before the forming step as in Comparative Example 3, the mixture is not heated, so that sufficient density cannot be obtained and a sample with high magnetic properties cannot be obtained. It was.

As in Examples 31 to 33, a sample having a higher (BH) max could be obtained by adding Sm ₂ Fe ₁₇ N ₃ , Nd ₂ Fe ₁₄ B, or Sm ₂ Co ₁₇ to MnBi.

As in Examples 34 to 38, a sample having a higher relative density could be obtained by adding a metal binder.

The method for producing a permanent magnet of the present invention is used as a method for producing a permanent magnet for an element of an electric / electronic device.

1. 1. Magnetic field forming apparatus 2. electromagnet Pressurizing device 4a. Upper punch 4b. Lower punch 4c. Dice 4d. 4. Heating device 5. Heat treatment apparatus Circulating atmosphere mechanism 6a. Circulating atmosphere outlet 6b. 6. Circulating atmosphere inlet Furnace 7a. Metal furnace wall 7b containing a heat insulating material or heat insulating layer. Heat treatment product inlet 7c. Heat treatment product outlet 7d. Temporary molded body accommodation space8. Near infrared heating source 9. Temporary molded body (or tray on which this is placed)
10.

Belt conveyors

11a, 11b. coil

Claims

A temporary molding step of obtaining a temporary molded body by pressing magnetic powder containing MnBi in a magnetic field;
A heating step of heating the temporary molded body by at least one method selected from infrared heating, microwave heating, and high-frequency induction heating;
A molding step of pressing the heated temporary molded body to obtain a molded body;
The manufacturing method of the permanent magnet characterized by having.
2. The permanent magnet according to claim 1, wherein the magnetic powder includes one or more magnetic materials selected from Sm—Fe—N, Nd—Fe—B, and Sm—Co in addition to MnBi. Manufacturing method.
The method for producing a permanent magnet according to claim 1, wherein the temporary molded body contains a metal binder.