JP2013131643A - Nitride magnetic material and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a highly magnetized soft magnetic material without using a rare metal.SOLUTION: The nitride magnetic material comprises: an alloy particle containing Fe as a main component and either of or both of Si and B; and an iron nitride which coats the surface of the alloy particle, wherein a particle diameter thereof is 100nm or less.

Description

  The present invention relates to a nitride magnetic body and a method for manufacturing a nitride magnetic body. In particular, the present invention relates to a soft magnetic material having high magnetization that can be used as an iron core material of a coil or a transformer or a magnetic material for a stator of a rotating machine, and a manufacturing method thereof.

Nitride _-Fe 16 _{N 2} magnetic as α _{".α -Fe} 16 _{N 2} are _known", since it exhibits high magnetization without using a rare metal, it is expected as a magnetic material. Regarding the magnetic characteristics of α ″ -Fe ₁₆ N ₂ , for example, the following Non-Patent Document 1 describes the relationship between the nitridation ratio and the magnetization when α-Fe particles are nitrided with a mixed gas of NH ₃ and N _2. Further, in Non-Patent Document 1 below, the presence of unreacted α-Fe is pointed out as one cause of α ″ -Fe ₁₆ N ₂ exhibiting giant magnetization. There is also an indication that the crystal structure of α ″ -Fe ₁₆ N ₂ is one cause of giant magnetization (see Patent Document 1 below).

As described above, α ″ -Fe ₁₆ N ₂ exhibits high magnetization. On the other hand, α ″ -Fe ₁₆ N _{2 has} a coercive force of about 200 kA / m, which is too low as a hard magnetic material. Therefore, research and development for increasing the coercive force of Fe ₁₆ N ₂ has been actively conducted. For example, Patent Document 2 below discloses a technique for increasing the coercivity of Fe ₁₆ N ₂ using a rare earth metal. On the other hand, the coercive force of about 200 kA / m is too high as the coercive force of the soft magnetic material. However, it cannot be said that research and development for reducing the coercive force of α ″ -Fe ₁₆ N ₂ while suppressing the reduction of magnetization has been sufficiently performed.

JP 2005-183932 A JP 2005-310857 A

K. Yamanaka et al., "Humidity effects in Fe16N2 fine powderpreparation by low-temperature nitridation", Journal of Solid State Chemistry, 183 (2010) 2236-2241

Fe ₄ N is known as an iron-based nitride exhibiting soft magnetism. However, Fe ₄ N has a low magnetization. In addition, as a device for increasing the magnetization of a soft magnetic material, a method using a rare metal such as Co is known. From the viewpoint of the availability and cost of a rare metal, a highly magnetized soft magnetic material without using a rare metal. Is required to be realized. In addition, when trying to achieve high magnetic permeability by reducing the coercive force, it is necessary to add an element that suppresses magnetocrystalline anisotropy and magnetostriction, and magnetization is reduced by the decrease in the amount of Fe added due to an increase in the added element. There was a problem of reduction.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a nitride magnetic body capable of realizing high magnetization as a soft magnetic material without using a rare metal. And a method of manufacturing a nitride magnetic body.

  In order to solve the above problems, according to one aspect of the present invention, an alloy particle containing Fe as a main component and containing one or both of Si and B, and an iron nitride covering the surface of the alloy particle, There is provided a nitride magnetic body characterized by having a particle size of 100 nm or less.

  With this configuration, it is possible to achieve high magnetization of alloy particles with a reduced amount of Fe addition by utilizing the giant magnetization generated due to the interface strain between iron nitride and α-Fe contained in the alloy particles. become. Further, Si and B contained in the alloy particles form a stable nitride, and thus serve as a protective film that contributes to a reduction in coercive force. Further, since the coercive force is reduced by reducing the particle size, the coercive force is reduced to 100 nm or less (for example, obtained by nitriding with an average primary particle size of about 80 nm or less). The magnetic force is suppressed to a value sufficient to function as a soft magnetic material. Note that if the particle size is larger than 100 nm, the nitriding reaction performed when forming the iron nitride hardly proceeds, so it is desirable that the particle size be 100 nm or less.

  The particle size is preferably 5 nm or more. Since it is currently difficult to form particles having a particle size smaller than 5 nm, the particle size is preferably 5 nm or more.

  The particle size is more preferably 50 nm or less. When the particle size is less than 50 nm, the coercive force decreases with the reduction of the particle size. Therefore, in order to form a soft magnetic material having a lower coercive force, it is desired that the particle size be 50 nm or less.

More preferably, the iron nitride has a crystal structure of Fe ₁₆ N ₂ . Thus, higher magnetization can be obtained by using the crystal structure of Fe ₁₆ N ₂ .

  Moreover, it is preferable that the volume fraction of the said iron nitride is 40-70 vol% with respect to the said alloy particle. If the volume fraction is less than 40 vol%, a region having high magnetization is not sufficiently formed at the interface between the iron nitride and the alloy particles, and the magnetization of the nitride magnetic body is lowered. On the other hand, if the volume fraction is larger than 70 vol%, the action of reducing the coercive force by the alloy particles is limited, and it is difficult to reduce the coercive force to a value sufficient to function as a soft magnetic material.

The alloy particles are preferably FeSi _X B _Y (X = 0 to 0.1, Y = 0 to 0.1. However, X and Y are not 0 at the same time). In order to function as a soft magnetic material having high magnetization, it is desired that the Fe content in the alloy particles is about 80% or more in terms of atomic percentage. Further, the solid solubility limit of Si and B with respect to Fe is about 10% in terms of atomic percentage.

  In order to solve the above problems, according to another aspect of the present invention, an alloy particle having a particle size of 100 nm or less, containing Fe as a main component, and containing one or both of Si and B is obtained at 300 ° C. A method for producing a nitride magnetic body is provided, which includes a step of reacting with a nitrogen-containing gas at the following temperature.

  Thus, by nitriding the surface of the alloy particle having soft magnetism at a low temperature (about 300 ° C. or less), it becomes possible to form a region having high magnetization at the interface between the iron nitride and the alloy particle. . As a result, it is possible to realize high magnetization of alloy particles with a reduced amount of Fe by utilizing the giant magnetization generated due to the interface strain between iron nitride and α-Fe contained in the alloy particles. Become. Further, Si and B contained in the alloy particles form a stable nitride, and thus serve as a protective film that contributes to a reduction in coercive force.

  Further, since the coercive force is reduced by reducing the particle size, the coercive force is reduced to 100 nm or less (for example, obtained by nitriding with an average primary particle size of about 80 nm or less). The magnetic force is suppressed to a value sufficient to function as a soft magnetic material. Note that if the particle size is larger than 100 nm, the nitriding reaction performed when forming the iron nitride hardly proceeds, so it is desirable that the particle size be 100 nm or less. By the way, considering the time required for the nitriding step and the temperature limit at which the nitriding reaction occurs, the temperature may be, for example, 100 ° C. or higher. In order to form a region having high magnetization sufficiently large, the temperature is more preferably 200 ° C. or lower.

  The particle size is preferably 5 nm or more. Since it is currently difficult to form particles having a particle size smaller than 5 nm, the particle size is preferably 5 nm or more.

  The particle size is more preferably 50 nm or less. When the particle size is less than 50 nm, the coercive force decreases with the reduction of the particle size. Therefore, in order to form a soft magnetic material having a lower coercive force, it is desired that the particle size be 50 nm or less.

More preferably, the iron nitride has a crystal structure of Fe ₁₆ N ₂ . Thus, higher magnetization can be obtained by using the crystal structure of Fe ₁₆ N ₂ .

  Moreover, it is preferable that the volume fraction of the said iron nitride is 40-70 vol% with respect to the said alloy particle. If the volume fraction is less than 40 vol%, a region having high magnetization is not sufficiently formed at the interface between the iron nitride and the alloy particles, and the magnetization of the nitride magnetic body is lowered. On the other hand, if the volume fraction is larger than 70 vol%, the action of reducing the coercive force by the alloy particles is limited, and it is difficult to reduce the coercive force to a value sufficient to function as a soft magnetic material.

The alloy particles are preferably FeSi _X B _Y (X = 0 to 0.1, Y = 0 to 0.1. However, X and Y are not 0 at the same time). In order to function as a soft magnetic material having high magnetization, it is desired that the Fe content in the alloy particles is about 80% or more in terms of atomic percentage. Further, the solid solubility limit of Si and B with respect to Fe is about 10% in terms of atomic percentage.

  As described above, according to the present invention, high magnetization can be realized as a soft magnetic material without using a rare metal.

It is a figure for demonstrating the composition of the alloy particle which comprises the nitride magnetic body which concerns on one Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the nitride magnetic body which concerns on the same embodiment. It is a figure for demonstrating the magnetic characteristic of the nitride magnetic body which concerns on the same embodiment. It is a diagram for explaining the relationship between the nitriding ratio in the case of nitriding the magnetization in a mixed gas of NH ₃ and N ₂ the alpha-Fe particles.

Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the drawing or description, the unit of magnetization may be expressed as [emu / g], but [emu / g] = [Am ² / kg].

<1: Introduction>
First, the cause of α ″ -Fe ₁₆ N ₂ exhibiting high magnetization will be considered. Conventionally, the cause of α ″ -Fe ₁₆ N ₂ exhibiting high magnetization has been considered to be due to its crystal structure (for example, (See Kaikai 2005-183932). However, recently, experimental results have shown that the magnetization of α ″ -Fe ₁₆ N ₂ is increased by leaving unreacted α-Fe particles in the nitriding step performed when α ″ -Fe ₁₆ N ₂ is generated. (K. Yamanaka et al., "Humidity effects in Fe16N2 fine powder
preparation by low-temperature nitridation ", Journal of Solid State
Chemistry, 183 (2010) 2236-2241; hereinafter the same report).

Part of the experimental results published in this report is shown in FIG. FIG. 4 shows the relationship between the nitriding ratio and the magnetization of the product when α-Fe particles are nitrided with a mixed gas of NH ₃ and N ₂ (black circles indicate experimental data). In this figure, the point of the stoichiometric composition of the α ″ -Fe ₁₆ N ₂ compound is that the nitriding ratio is 11.1 [at.%] In atomic percentage. However, referring to the experimental data, The point where the magnetization is maximized is included in a region where the nitriding ratio is 11.1 [at.%] Or less (a region of about 8 to 10 [at.%]). This suggests that the presence of H contributes to the giant magnetization of the α ″ -Fe ₁₆ N ₂ compound.

In addition, the authors of the report seem to aim at realization of an excellent hard magnetic material by a technique for increasing the magnetization of the α ″ -Fe ₁₆ N ₂ compound using the mixed state of α-Fe particles. On the other hand, the present inventor aimed to realize a soft magnetic material having high magnetization with reference to the result of the report, and as a result, the present inventor has invented a composition of a nitride magnetic material and a manufacturing method thereof described below. The details will be described below.

<2: Embodiment>
An embodiment of the present invention will be described. The nitride magnetic body according to the present embodiment is mainly composed of alloy particles containing Fe as a main component and containing one or both of Si and B, and iron nitride covering the surface of the alloy particles. . The nitride magnetic material is characterized by the composition and particle size of the alloy particles constituting the nitride magnetic material and the manufacturing process thereof. In the following description, α ″ -Fe ₁₆ N ₂ is assumed as an example of iron nitride, and FeSi _{X BY} is assumed as an example of alloy particles.

[2-1: Composition of synthetic particles]
First, the composition of alloy particles constituting the nitride magnetic body according to the present embodiment will be described with reference to FIG. The equilateral triangle shown in FIG. 1 represents the composition of the alloy particles, with the apex (hereinafter referred to as a reference point) written as Fe as a reference, the Si content ratio increases in the X direction, and Y It means that the content ratio of B increases as it goes in the direction.

The alloy particles according to the present embodiment include at least one of Si and B in addition to Fe (α-Fe particles) as a main component. Therefore, the Si content ratio X and the B content ratio Y do not both become zero. Further, when the content ratio of Si and B is increased, Fe ₃ B and the like are precipitated. Therefore, the ratio of Fe contained in the alloy particles is preferably about 80% or more. Therefore, an enlarged view in the vicinity of the range where the Fe content ratio is about 80% or more is shown in FIG. Further, the solid solubility limit of Si and B with respect to Fe is about 10%. Therefore, the range that can be taken as the composition of the alloy particles according to this embodiment is a parallelogram range surrounded by the reference point and the three black circles shown in the enlarged view.

For example, when the composition of the alloy particles is Fe + B (when X = 0), the range from the reference point to the black circle marked Fe _0.9 B _0.1 is the range that can be taken as the composition of the alloy particles. Similarly, when the composition of the alloy particles is Fe + Si (when Y = 0), the range from the reference point to the black circle marked Fe _0.9 Si _0.1 is the range that can be taken as the composition of the alloy particles. . Further, when Si and B are dissolved to the maximum, the composition of the alloy particles is Fe _0.8 Si _0.1 B _0.1 . Si and B form a stable nitride in the nitriding step. The nitride serves as a protective film and contributes to a reduction in coercive force. Therefore, the coercive force can be effectively reduced by increasing both the solid solution amounts of Si and B.

The composition of the alloy particles according to the present embodiment has been described above. Incidentally, the point indicated by white circles in FIG. 1 _{(FeSi 0.03} B _0.03) corresponds to the later-described experimental conditions (Example 2).

[2-2: Manufacturing method of nitride magnetic body]
Next, a method for manufacturing a nitride magnetic body according to the present embodiment will be described with reference to FIG. FIG. 2 is a flow diagram showing a manufacturing process of the nitride magnetic body according to the present embodiment.

As shown in FIG. 2, first, as starting materials, metal particles (composition: Fe + (Si, B), particle size 5 to 80 nm) or Fe oxide (metal composition: Fe + (Si, B), particle size 5 80 nm) is charged into the reaction vessel (S101). Next, a mixed gas of hydrogen (or fluorine) and nitrogen is circulated in the reaction vessel, and reduction treatment is performed at 400 to 600 ° C. for 10 to 100 hours (S102). After the reduction treatment, the gas circulating in the reaction vessel is switched to a mixed gas of NH ₃ and nitrogen, and nitriding treatment is performed at 100 ° C. to 300 ° C. (more preferably 200 ° C. or less) for 10 to 100 hours ( S103).

  As described above, when alloy particles having soft magnetic properties are nitrided at low temperature, a region having high magnetization is formed at the interface between the iron nitride formed on the surface of the alloy particles and the alloy particles. As a result, the magnetization of the alloy particles with a reduced Fe addition amount is reinforced, and a nitride magnetic body having high magnetization and soft magnetic properties is formed.

  In the example of FIG. 2, the particle size of the primary particles is set so that the particle size of the nitride magnetic body is 100 nm or less, but this is a step when the particle size is set to exceed 100 nm. This is because the nitriding reaction does not proceed in S103. However, in the range where the particle size is 50 nm or less, the smaller the particle size, the lower the coercive force. Therefore, it is more preferable to set the particle size to 50 nm or less. In addition, the setting of the particle size of 5 nm or more in the example of FIG. 2 is attributed to the size of the primary particles that can be prepared at the present stage being 5 nm or more.

  The method for manufacturing the nitride magnetic body according to the present embodiment has been described above.

[2-3: Magnetic properties of nitride magnetic body]
Next, the magnetic characteristics of the nitride magnetic body according to the present embodiment will be described with reference to FIG. FIG. 3 shows the magnetic properties (Examples 1 and 2) exhibited by two types of nitride magnetic materials produced by the production method shown in FIG. 2, and the magnetic properties exhibited by four types of compounds prepared for comparison. (Comparative Examples 1 to 4) are shown.

The composition of the nitride magnetic body according to Example 1 is α ″ -Fe ₁₆ N ₂ + FeSi _0.03 . The composition of the nitride magnetic body according to Example 2 is α ″ -Fe ₁₆ N ₂ + FeSi. _0.03 B _0.03 (see white circle in FIG. 1). On the other hand, the composition of the compound according to Comparative Example 1 is α ″ -Fe ₁₆ N _2. The composition of the compound according to Comparative Example 2 is Fe ₄ N. Furthermore, the composition of the compound according to Comparative Example 3 is used. Is FeSi _0.03 , and the composition of the compound according to Comparative Example 4 is FeSi _0.03 B _0.03 .

Incidentally, Examples 1 and 2, the results of the generated α in magnetic nitride _"-Fe 16 _{N 2} volume fraction was measured at about 40~50vol%. The measurement is of the following First, change the reaction time to about 2, 4, 8, and 16 hours at about 200 ° C. to prepare samples with different amounts of nitride, and then use an oxygen / nitrogen analyzer (for example, LECO Japan GK). The amount of nitride in each sample is measured from the nitrogen content using TCH600 etc. Then, the main peak intensities of α-Fe and nitride in the X-ray diffraction of the sample are measured, and the nitrogen analysis result and A calibration curve is created from the intensity of X-ray diffraction, and the amount of nitride produced is determined with this.

(About Example 1)
Example 1 is a nitride magnetic body in which FeSi _0.03 is used as alloy particles and α ″ -Fe ₁₆ N ₂ is formed on the surface by nitriding treatment. FIG. 3 shows the nitriding according to Example 1. The measurement results in the case where the particle size of the magnetic material is about 100 nm are shown, and the particle size can be measured by calculating the X-ray diffraction peak spread using the Hall method. (The Scherrer equation can be used to evaluate the crystal size from the line width of the X-ray diffraction peak.) Also, the magnetization Ms and retention ratio Hc of the nitride magnetic material are determined by a vibrating sample magnetometer (for example, RIHV Electronics BHV-525, etc. manufactured by Riken Denshi Co., Ltd. The measurement method is the same for other compounds.

The magnetization Ms of the nitride magnetic body showed Ms = 180 [emu / g]. This value is 30 [emu / g] larger than the magnetization (Ms = 150 [emu / g]) of Fe ₄ N (Comparative Example 2), which is a typical soft magnetic material. The magnetization Ms of the nitride magnetic body is close to the magnetization (Ms = 190 [emu / g]) of α ″ -Fe ₁₆ N ₂ alone (Comparative Example 1). The magnetization Ms of the magnetic material shows a larger value than the magnetization of FeSi _0.03 alone (Comparative Example 3).

On the other hand, the coercive force Hc of the nitride magnetic body according to Example 1 was Hc = 2.5 × 10 ³ [A / m]. This value is an order of magnitude smaller than the coercive force (Hc = 80 × 10 ³ [A / m]) of α ″ -Fe ₁₆ N ₂ alone (Comparative Example 1). The magnetic force Hc is smaller than the coercive force (Hc = 4.0 × 10 ³ [A / m]) of Fe ₄ N (Comparative Example 2), and the magnetization of the nitride magnetic body Ms has a value comparable to the coercive force of FeSi _0.03 alone (Comparative Example 3).

From the above comparison results, it was confirmed that the nitride magnetic body of Example 1 exhibited high magnetization approaching that of α ″ -Fe ₁₆ N ₂ alone (Comparative Example 1). Further, the nitride of Example 1 It was confirmed that the magnetic material exhibited a coercive force lower than the coercive force (Hc = 4.0 × 10 ³ [A / m]) of Fe ₄ N (Comparative Example 2), that is, nitriding according to Example 1. It was confirmed that the magnetic material can achieve high magnetization as a soft magnetic material.

(About Example 2)
Example 2 is a nitride magnetic body in which FeSi _0.03 B _0.03 is used as alloy particles, and α ″ -Fe ₁₆ N ₂ is formed on the surface by nitriding. FIG. The measurement result in the case where the particle size of the nitride magnetic body according to No. 2 is about 100 nm is shown.

The magnetization Ms of the nitride magnetic body showed Ms = 190 [emu / g]. This value is 40 [emu / g] larger than the magnetization (Ms = 150 [emu / g]) of Fe ₄ N (Comparative Example 2), which is a typical soft magnetic material. The magnetization Ms of the nitride magnetic body has the same value as the magnetization (Ms = 190 [emu / g]) of α ″ -Fe ₁₆ N ₂ alone (Comparative Example 1). The magnetization Ms of the magnetic material shows a larger value than the magnetization of FeSi _0.03 B _0.03 alone (Comparative Example 4).

On the other hand, the coercive force Hc of the nitride magnetic body according to Example 2 was Hc = 0.8 × 10 ³ [A / m]. This value is an order of magnitude smaller than the coercive force (Hc = 80 × 10 ³ [A / m]) of α ″ -Fe ₁₆ N ₂ alone (Comparative Example 1). The magnetic force Hc is much smaller than the coercive force (Hc = 4.0 × 10 ³ [A / m]) of Fe ₄ N (Comparative Example 2). Is much smaller than the coercive force of FeSi _0.03 B _0.03 alone (Comparative Example 4).

From the above comparison results, it was confirmed that the nitride magnetic body of Example 2 exhibited high magnetization equivalent to that of α ″ -Fe ₁₆ N ₂ alone (Comparative Example 1). It was confirmed that the magnetic material exhibits a coercivity much lower than the coercivity (Hc = 4.0 × 10 ³ [A / m]) of Fe ₄ N (Comparative Example 2). It was confirmed that the nitride magnetic body according to the present invention can achieve a high magnetization as a soft magnetic material, and the nitride magnetic body of Example 2 has a large magnetization and a remarkably low coercive force as compared with Example 1. It was confirmed that

(Discussion)
Here, I would like to consider the above comparison results in more detail.

The nitride magnetic body of Example 1 can be considered to be formed by nitriding the compound of Comparative Example 3 to form α ″ -Fe ₁₆ N ₂ on the surface. When comparing the magnetization Ms of both, ΔMs = 10 It can be seen that there is a difference of about [emu / g], but there is no significant difference between the two in terms of coercive force Hc. Although the influence of the high magnetization region formed at the interface contributes to the increase of magnetization as a whole, the effect of reducing the coercive force inherent to FeSi _0.03 by nitriding is not so much seen.

Further, the nitride magnetic body of Example 2 can be regarded as a product obtained by nitriding the compound of Comparative Example 4 to form α ″ -Fe ₁₆ N ₂ on the surface. Comparing the magnetization Ms of both, ΔMs When the magnetization of Comparative Example 3 is compared with the magnetization of Comparative Example 4, the magnetization of Comparative Example 4 is about 10 [emu / g] lower. This is considered to be due to an increase in the amount of additive elements contained in the alloy particles, while there is no significant difference in coercive force Hc between Comparative Example 3 and Comparative Example 4. Therefore, when the alloy particles are viewed alone, there is no significant difference in the influence of the additive elements Si and B on the coercive force Hc.

However, when the coercive force Hc of Example 2 and the coercive force Hc of Comparative Example 4 are compared, a difference of 1.7 × 10 ³ [A / m] occurs. This is considered that the nitride of B formed at the interface in the nitriding process exhibits the effect of greatly reducing the coercive force Hc. Therefore, in order to effectively reduce the coercive force Hc, it is considered effective to add B as an additive element contained in the alloy particles. Of course, in the case of Example 2, as in Example 1, the influence of the high magnetization region formed at the interface by the nitriding treatment of the alloy particles contributes to the increase of the magnetization as a whole, and B is added to the additive element. There are no negative effects of the addition.

  The magnetic characteristics of the nitride magnetic body according to this embodiment have been described above.

[2-4: Effect]
As described above, a soft magnetic material having high magnetization can be obtained by applying the technique of the present embodiment in which alloy particles having a low coercive force are nitrided at low temperature and iron nitride is formed on the surface of the alloy particles. Further, the torque of the rotating machine can be improved by using this soft magnetic material as the iron core material of the stator. For example, in passing a moving object to the current i of the length L in a magnetic field of flux density B _m, the force F generated is determined by F = i * B m * _L by Fleming's rule. Usually, in a rotating machine, the current i and the length L are limited because of restrictions on the shape and power. Therefore, to increase the force F that occurs, it is necessary to increase the magnetic flux density B _m.

The value of the magnetic flux density B _m depends on the core material used, currently, the magnetic flux density B _m of FeSi alloys are used industrially is about 1.7 [T] at the maximum. In contrast, magnetic nitride according to this embodiment, it is possible to obtain a high magnetic flux density B _m of about 1.9 [T] in the case of the second embodiment shown in FIG. That is, by using the nitride magnetic body according to the present embodiment, it is possible to greatly exceed the limit value of the currently used iron core material. Since the torque of the rotating machine in proportion to the increase of the magnetic flux density B _m is increased, you are possible to obtain a rotary machine of the high output as a result. Conversely, when designing a rotary machine of the same output, the magnetic flux density B _m can be suppressed larger amount corresponding length L, a further downsizing of the rotary machine becomes possible.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

Claims (12)

Alloy particles mainly composed of Fe and containing one or both of Si and B;
An iron nitride coating the surface of the alloy particles;
Have
A nitride magnetic material having a particle size of 100 nm or less. The nitride magnetic body according to claim 1, wherein the particle size is 5 nm or more. The nitride magnetic body according to claim 1, wherein the particle size is 50 nm or less. The nitride magnetic body according to claim 1, wherein the iron nitride has a crystal structure of Fe ₁₆ N ₂ . 5. The nitride magnetic body according to claim 1, wherein a volume fraction of the iron nitride is 40 to 70 vol% with respect to the alloy particles. The alloy particles are FeSi _X B _Y (X = 0 to 0.1, Y = 0 to 0.1, where X and Y are not 0 at the same time). The nitride magnetic body according to any one of 5. A step of reacting an alloy particle having a particle size of 100 nm or less, containing Fe as a main component and containing one or both of Si and B, with a nitrogen-containing gas at a temperature of 300 ° C. or less. A method for producing a magnetic substance. The method for producing a nitride magnetic body according to claim 7, wherein the particle size is 5 nm or more. The method for producing a nitride magnetic body according to claim 7 or 8, wherein the particle size is 50 nm or less. The method for producing a nitride magnetic body according to claim 7, wherein the iron nitride has a crystal structure of Fe ₁₆ N ₂ . The method for producing a nitride magnetic body according to any one of claims 7 to 10, wherein the volume fraction of the iron nitride is 40 to 70 vol% with respect to the alloy particles. The alloy particles are FeSi _X B _Y (X = 0 to 0.1, Y = 0 to 0.1, where X and Y are not 0 at the same time). 11. The nitride magnetic body according to any one of 11 above.

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