Compacted powder materials and rotating electrical machines

Abstract

To provide a pressed powder material having an excellent magnetic characteristic and a rotary electric machine.SOLUTION: A pressed powder material according to an embodiment includes a flat surface and a magnetic metal phase that contains at least one first element selected from a group of Fe, Co, and Ni. The pressed powder material comprises: a plurality of flat magnetic metal powders in which an average thickness is 10nm or more and 100 μm or less, an average value of a ratio of an average length in the flat surface against a thickness is 5 or more 10000 or less; and an intercalary phase that exists between the flat magnetic metal powders, and contains at least one second element selected from a group of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). In the pressed powder material, an orientation variation of the plurality of flat magnetic metal particles is 30 degrees or more and 45 degrees or less in a predetermined cross section vertical to a flat surface included in the pressed powder material, and a contact ratio of the plurality of flat magnetic metal particles is 3% or more and 10% or less, and a curvature rate of the plurality of flat magnetic metal particles is 0.01% or more and 0.6% or less.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a compacted powder material and a rotating electric machine. [Background technology]

[0002] Currently, soft magnetic materials are extremely important materials, being used in components of various systems and devices, such as rotating electrical machines (e.g., motors, generators, etc.), transformers, inductors, magnetic inks, and antenna devices. These components utilize the real part of the magnetic permeability (real part of the relative magnetic permeability) μ' of the soft magnetic material, so when actually using it, it is preferable to control μ' to match the frequency band being used. Furthermore, to achieve a highly efficient system, it is preferable to use a material with as low loss as possible. In other words, it is preferable to make the imaginary part of the magnetic permeability (imaginary part of the relative magnetic permeability) μ" (corresponding to loss) as small as possible. With regard to loss, the loss factor tan δ (= μ" / μ' × 100(%)) is one guideline, and the smaller μ" is relative to μ', the smaller the loss factor tan δ becomes, which is preferable. To achieve this, it is preferable to make the iron loss small under actual operating conditions, that is, it is preferable to make the eddy current loss, hysteresis loss, ferromagnetic resonance loss, and residual loss (other losses) as small as possible. In order to reduce eddy current loss, it is effective to increase the electrical resistance, reduce the size of the metal parts, and subdivide the magnetic domain structure. In order to reduce hysteresis loss, it is effective to reduce the coercive force and increase the saturation Increasing the saturation magnetization of soft magnetic materials is effective. Increasing the anisotropy field of a material to increase the ferromagnetic resonance frequency is effective in reducing ferromagnetic resonance loss. Furthermore, with the increasing demand for high-power electrical power in recent years, materials are required to have low loss, especially under operating conditions where the effective magnetic field applied to them is large, such as high currents and voltages. To achieve this, it is desirable for soft magnetic materials to have as large a saturation magnetization as possible to avoid magnetic saturation. Furthermore, in recent years, higher frequencies have enabled the miniaturization of devices, and the frequency bands used by systems and devices are becoming higher. This has created an urgent need for the development of magnetic materials with excellent properties, including high permeability and low loss at high frequencies.

[0003] In recent years, growing awareness of energy conservation and environmental issues has led to a demand for maximizing system efficiency. Since motor systems account for a large portion of the world's electricity consumption, increasing motor efficiency is particularly important. The cores and other components of motors are made of soft magnetic materials, and it is essential to maximize the permeability and saturation magnetization of these materials and minimize losses. Furthermore, the magnetic wedges used in motors are also required to minimize losses. Similar demands are placed on systems that use transformers. In addition to increasing efficiency, there is also a growing demand for miniaturization of motors and transformers. To achieve miniaturization, it is important to maximize the permeability and saturation magnetization of soft magnetic materials. Furthermore, it is also important to maximize saturation magnetization to prevent magnetic saturation. Furthermore, there is a growing demand for higher system operating frequencies, necessitating the development of low-loss materials in the high-frequency band.

[0004] Soft magnetic materials, which have high magnetic permeability and low loss, are also used in inductance elements and antenna devices. In particular, their application to power inductance elements in power semiconductors has recently attracted attention. In recent years, the importance of energy conservation and environmental protection has been widely advocated, leading to calls for reducing CO2 emissions and dependence on fossil fuels. As a result, the development of electric and hybrid vehicles as alternatives to gasoline-powered vehicles has been vigorously pursued. Furthermore, technologies for utilizing natural energy sources such as solar and wind power are considered key technologies for an energy-saving society, and developed countries are actively developing these technologies. Furthermore, the importance of building environmentally friendly energy-saving systems, such as home energy management systems (HEMS) and building energy management systems (BEMS), which use smart grids to control electricity generated by solar and wind power generators and efficiently supply and demand it to homes, offices, and factories, has been actively advocated. Power semiconductors play a key role in this trend toward energy conservation. Power semiconductors are semiconductors that efficiently control high power and energy. They include discrete power semiconductors such as IGBTs (insulated gate bipolar transistors), MOSFETs, power bipolar transistors, and power diodes, as well as power supply circuits such as linear regulators and switching regulators, and even power management logic LSIs that control these devices. Power semiconductors are widely used in a variety of devices, including home appliances, computers, automobiles, and railways. As these applications become more widespread and their use in these devices increases, the power semiconductor market is expected to see significant growth. For example, power semiconductors are used in almost all inverters in many home appliances, enabling significant energy savings. While silicon is currently the mainstream material for power semiconductors, the use of silicon carbide (SiC) and gallium nitride (GaN) is considered effective for further improving efficiency and miniaturizing devices. SiC and GaN have larger bandgaps and breakdown fields than silicon, allowing for higher voltage resistance and thinner device thickness.This allows for a reduction in the on-resistance of the semiconductor, which is effective in reducing loss and increasing efficiency. In addition, because SiC and GaN have high carrier mobility, it is possible to increase the switching frequency, which is effective in miniaturizing the device. Furthermore, SiC in particular has a higher thermal conductivity than Si, which allows for high-temperature operation with a high heat dissipation capacity, simplifying the cooling mechanism. transformation This will be effective in miniaturizing the devices in the future. From this perspective, the development of SiC and GaN power semiconductors is being actively pursued. However, to achieve this, it is essential to develop power inductor elements to be used in conjunction with power semiconductors, that is, high-permeability soft magnetic materials (high permeability and low loss). In this case, the properties required of magnetic materials are not only high permeability and low magnetic loss in the driving frequency band, but also high saturation magnetization that can handle large currents. When saturation magnetization is high, magnetic saturation is unlikely to occur even when a strong magnetic field is applied, and a decrease in the effective inductance value can be suppressed. This improves the DC superposition characteristics of the device and increases the efficiency of the system.

[0005] Furthermore, magnetic materials with high magnetic permeability and low loss at high frequencies are expected to be applied to devices in high-frequency communication equipment, such as antenna devices. One method for miniaturizing and power-saving antennas is to use an insulating substrate with high magnetic permeability (high magnetic permeability and low loss) as the antenna substrate, thereby capturing radio waves that would otherwise reach the electronic components or boards in the communication equipment and transmitting and receiving signals without them reaching the electronic components or boards. This method not only enables the antenna to be miniaturized and power-saving, but also makes it possible to broaden the resonant frequency band of the antenna, which is preferable.

[0006] Other properties required for incorporation into the above systems and devices include high thermal stability, high strength, and high toughness. Furthermore, for application to complex shapes, a compact is preferable to a plate or ribbon shape. However, it is generally known that compacting a powder deteriorates properties such as saturation magnetization, magnetic permeability, loss, strength, toughness, and hardness, and therefore improving these properties is desirable.

[0007] Next, the types and problems of existing soft magnetic materials will be explained.

[0008] Silicon steel (FeSi) is an existing soft magnetic material for systems below 10 kHz. Silicon steel has a long history and is used as the core material for most high-power rotating electrical machines and transformers. While efforts to improve its properties have progressed since its discovery, evolving from non-oriented to oriented silicon steel, improvements in its properties have plateaued in recent years. Its properties must simultaneously satisfy high saturation magnetization, high permeability, and low loss. While active research into materials superior to silicon steel has focused on amorphous and nanocrystalline compositions, no material composition has yet been found that surpasses silicon steel in all respects. Research into powder compacts that can be applied to complex shapes has also been conducted, but these compacts have the disadvantage of poorer properties compared to plates and ribbons.

[0009] Existing soft magnetic materials for 10 kHz to 100 kHz systems include Sendust (Fe-Si-Al), nanocrystalline Finemet (Fe-Si-B-Cu-Nb), ribbons and compacts of Fe-based or Co-based amorphous glass, and MnZn-based ferrite materials. However, none of these materials fully satisfy the requirements of high magnetic permeability, low loss, high saturation magnetization, high thermal stability, high strength, high toughness, and high hardness.

[0010] Existing soft magnetic materials for frequencies above 100 kHz (above MHz band) include NiZn ferrite and hexagonal ferrite, but their magnetic properties at high frequencies are insufficient.

[0011] In view of the above, it is desirable to develop magnetic materials that have high saturation magnetization, high magnetic permeability, low loss, high thermal stability, and excellent mechanical properties. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 2017-059816 Summary of the Invention [Problem to be solved by the invention]

[0013] The problem to be solved by the present invention is to provide a powder material having excellent magnetic properties and a rotating electric machine using the same. [Means for solving the problem]

[0014] The compacted powder material of the embodiment is a compacted powder material comprising a plurality of flat magnetic metal particles having a flat surface and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, an average thickness of 10 nm or more and 100 μm or less, and an average ratio of the average length within the flat surface to the thickness of 5 or more and 10,000 or less, and an intervening phase present between the flat magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). In the compacted powder material, in a predetermined cross section perpendicular to the plane of the compacted powder material, the orientation variation of the plurality of flat magnetic metal particles is 30 degrees or more and 45 degrees or less, the proximity ratio of the plurality of flat magnetic metal particles is 3% or more and 10% or less, and the curvature ratio of the plurality of flat magnetic metal particles contained in the compacted powder material is Average of The powder material has a Si content of 0.01% or more and 0.6% or less. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 3 is a conceptual diagram showing an example of how to determine the thickness of a flat magnetic metal particle according to the first embodiment. [Figure 2] 2 is a conceptual diagram for explaining how to determine the maximum length and minimum length within the flat surface of a flat magnetic metal particle of the first embodiment. FIG. [Figure 3] FIG. 10 is a conceptual diagram for explaining another example of how to determine the maximum length and minimum length within the flat surface of a flat magnetic metal particle of the first embodiment. [Figure 4]1 is a schematic diagram showing the direction in which the coercive force of a flat magnetic metal particle of the first embodiment was measured, changing the direction every 22.5 degrees relative to an angle of 360 degrees within the flat surface. [Figure 5] 1 is a perspective schematic view of a flat magnetic metal particle according to a first embodiment. FIG. [Figure 6] 1 is a schematic diagram of a flat magnetic metal particle according to a first embodiment, viewed from above. [Figure 7] FIG. 4 is a schematic diagram of a flat magnetic metal particle according to a second embodiment. [Figure 8] FIG. 10 is a schematic diagram of a compacted powder material according to a third embodiment. [Figure 9] 10A to 10C are schematic diagrams showing examples of the arrangement of flat magnetic metal particles in a plane parallel to each cross section in the third embodiment. [Figure 10] FIG. 11 is a schematic diagram showing the angle formed between a plane parallel to the flat surface of a flat magnetic metal particle and a plane of the compacted powder material in the third embodiment. [Figure 11] 10A to 10C are schematic diagrams illustrating a method for producing a powder material according to a third embodiment. [Figure 12] 10 is a microscope (SEM) photograph of a predetermined cross section of a compacted powder material in the third embodiment. [Figure 13] 10 is a schematic diagram showing a method for calculating a proximity ratio in a predetermined cross section of a compacted powder material according to the third embodiment. FIG. [Figure 14] 10 is a schematic diagram showing a method for calculating the curvature of a predetermined cross section of a compacted powder material according to the third embodiment. FIG. [Figure 15] FIG. 10 is a conceptual diagram of a motor system according to a fourth embodiment. [Figure 16] FIG. 10 is a conceptual diagram of a motor according to a fourth embodiment. [Figure 17] FIG. 10 is a conceptual diagram of a motor core (stator) according to a fourth embodiment. [Figure 18] FIG. 10 is a conceptual diagram of a motor core (rotor) according to a fourth embodiment. [Figure 19] FIG. 10 is a conceptual diagram of a transformer according to a fourth embodiment. [Figure 20]10 is a conceptual diagram of an inductor (a ring-shaped inductor and a rod-shaped inductor) according to a fourth embodiment. FIG. [Figure 21] FIG. 10 is a conceptual diagram of an inductor (chip inductor, planar inductor) according to a fourth embodiment. [Figure 22] FIG. 10 is a conceptual diagram of a generator according to a fourth embodiment. [Figure 23] FIG. 2 is a conceptual diagram showing the relationship between the direction of magnetic flux and the arrangement direction of compacted powder material. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0017] (First embodiment) The multiple flat magnetic metal particles of this embodiment have flat surfaces and a magnetic metal phase containing Fe, Co, and Si, wherein the amount of Co is 0.001 at% or more and 80 at% or less of the total amount of Fe and Co, the amount of Si is 0.001 at% or more and 30 at% or less of the entire magnetic metal phase, the average thickness of the multiple flat magnetic metal particles is 10 nm or more and 100 μm or less, the average ratio of the average length within the flat surfaces to the thickness is 5 or more and 10,000 or less, and the multiple flat magnetic metal particles have a difference in coercivity depending on the direction within the flat surfaces.

[0018] In addition, the multiple flat magnetic metal particles of this embodiment have flat surfaces and a magnetic metal phase consisting of at least one first element selected from the group consisting of Fe, Co, and Ni and an additive element, wherein the additive element includes B and Hf, the total amount of the additive elements is 0.002 at% or more and 80 at% or less of the entire magnetic metal phase, the average thickness of the multiple flat magnetic metal particles is 10 nm or more and 100 μm or less, the average ratio of the average length within the flat surfaces to the thickness is 5 or more and 10,000 or less, and the multiple flat magnetic metal particles have a difference in coercivity depending on the direction within the flat surfaces.

[0019] The flat magnetic metal particles are flaky particles (flattened particles) that have a flaky shape (flattened shape).

[0020] The thickness refers to the average thickness of a single flat magnetic metal particle. Any method can be used to determine the thickness, as long as it can determine the average thickness of a single flat magnetic metal particle. For example, a cross section perpendicular to the flat surface of a flat magnetic metal particle can be observed using a transmission electron microscope (TEM), a scanning electron microscope (SEM), or an optical microscope. Ten or more arbitrary locations can be selected along the flat surface of the observed cross section of the flat magnetic metal particle, the thickness of each selected location can be measured, and the average value can be calculated. Alternatively, ten or more equally spaced locations can be selected along the flat surface of the observed cross section of the flat magnetic metal particle from one end to the other (it is preferable not to select the end and other ends because they are special locations), the thickness of each selected location can be measured, and the average value can be calculated. Figure 1 is a conceptual diagram showing an example of how to determine the thickness of a flat magnetic metal particle according to the first embodiment. Figure 1 specifically illustrates how to determine the thickness in this case. Ten points are selected at equal intervals from one end to the other in the direction of the flat surface (excluding the ends), and the thicknesses at each point are t1, t2, . . ., t 10 Then, the thickness of the flat magnetic metal particle is (t1 + t2 + + t 10 ) / 10. In either case, it is preferable to measure as many locations as possible, since this allows for obtaining average information. If the cross-sectional contour line is highly uneven or has a rough surface, making it difficult to determine the average thickness as is, it is preferable to smooth the contour line with an average straight line or curve, as appropriate, before carrying out the above method.

[0021] Furthermore, the average thickness refers to the average value of the thickness of a plurality of flat magnetic metal particles, and is distinguished from the simple "thickness" mentioned above. When determining the average thickness, it is preferable to use an average value for 20 or more flat magnetic metal particles. It is also preferable to determine the average thickness for as many flat magnetic metal particles as possible, as this allows for obtaining average information. Furthermore, if it is not possible to observe 20 or more flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible. of It is preferable to observe the flat magnetic metal particles and use the average value. The average thickness of the flat magnetic metal particles is preferably 10 nm or more and 100 μm or less. More preferably, it is 10 nm or more and 1 μm or less, and even more preferably, it is 10 nm or more and 100 nm or less. Furthermore, it is preferable that the flat magnetic metal particles include those having a thickness of 10 nm or more and 100 μm or less, more preferably, 10 nm or more and 1 μm or less, and even more preferably, it is 10 nm or more and 100 nm or less. This is preferable because it can sufficiently reduce eddy current loss when a magnetic field is applied in a direction parallel to the flat surfaces. Furthermore, a smaller thickness is preferable because the magnetic moment is confined in a direction parallel to the flat surfaces, making it easier for magnetization to proceed by rotational magnetization. When magnetization proceeds by rotational magnetization, magnetization tends to proceed reversibly, resulting in a smaller coercive force, which is preferable because it reduces hysteresis loss.

[0022] The average length of a flat magnetic metal particle is defined as (a + b) / 2, where a is the maximum length within the flat surface and b is the minimum length. The maximum length a and minimum length b can be calculated as follows. For example, consider the rectangle with the smallest area among the rectangles circumscribing the flat surface. The length of the long side of this rectangle is the maximum length a, and the length of the short side is the minimum length b. Figure 2 is a conceptual diagram for explaining how to calculate the maximum and minimum lengths within the flat surface of a flat magnetic metal particle according to the first embodiment. Figure 2 is a schematic diagram showing the maximum length a and minimum length b calculated using the above method for several flat magnetic metal particles. Note that Figure 2 illustrates the flat surface of the flat magnetic metal particle as viewed from above. Like the average thickness, the maximum length a and minimum length b can be calculated by observing the flat magnetic metal particle with a TEM, SEM, or optical microscope. It is also possible to calculate the maximum length a and minimum length b by performing image analysis of a micrograph on a computer. In either case, it is preferable to calculate the maximum length a and minimum length b for 20 or more flat magnetic metal particles. In addition, it is preferable to measure as many flat magnetic metal particles as possible, as this allows for obtaining average information. Furthermore, if it is not possible to observe more than 20 flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and adopt the average value for them. Furthermore, since it is preferable to obtain as average a value as possible, it is preferable to perform observation or image analysis in a state where the flat magnetic metal particles are uniformly dispersed (in a state where multiple flat magnetic metal particles with different maximum and minimum lengths are dispersed as randomly as possible). For example, it is preferable to perform observation or image analysis by thoroughly stirring multiple flat magnetic metal particles and attaching them to tape, or by dropping multiple flat magnetic metal particles from above and attaching them to tape.

[0023] However, depending on the flat magnetic metal particle, determining the maximum length a and minimum length b using the above method may result in a determination that does not capture the true nature of the particle. Figure 3 is a conceptual diagram illustrating another example of how to determine the maximum and minimum lengths within the flat surface of the flat magnetic metal particle of the first embodiment. Note that Figure 3 illustrates the flat surface of the flat magnetic metal particle as viewed from above. For example, in the case of Figure 3, the flat magnetic metal particle is elongated and curved. In this case, the maximum and minimum lengths of the flat magnetic metal particle are essentially the lengths a and b shown in Figure 2. As such, the method of determining the maximum lengths a and b is not completely unique. Basically, it is acceptable to use the method of "considering the rectangle with the smallest area among the rectangles circumscribing the flat surface, and setting the length of the long side of that rectangle as the maximum length a and the length of the short side of that rectangle as the minimum length b." However, depending on the shape of the particle, if this method does not capture the true nature of the particle, the maximum length a and minimum length b can be determined flexibly to capture the true nature of the particle. The thickness t is defined as the length perpendicular to the flat surface. The ratio A of the average length within the flat surface to the thickness is defined as A = ((a + b) / 2) / t, where a is the maximum length, b is the minimum length, and t is the thickness.

[0024] The average ratio of the average length within the flat surface to the thickness of the flat magnetic metal particles is preferably 5 or more and 10,000 or less, because this increases the magnetic permeability and also increases the ferromagnetic resonance frequency, thereby reducing ferromagnetic resonance loss.

[0025] The ratio of the average length within the flat surface to the thickness is the average value. Preferably, the average value for 20 or more flat magnetic metal particles is used. It is also preferable to measure as many flat magnetic metal particles as possible, as this allows for obtaining average information. If it is not possible to observe 20 or more flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and use the average value for them. For example, if there are particles Pa, Pb, and Pc, each with thicknesses Ta, Tb, and Tc, and average lengths within the flat surface La, Lb, and Lc, the average thickness is calculated as (Ta + Tb + Tc) / 3, and the average ratio of the average length within the flat surface to the thickness is calculated as (La / Ta + Lb / Tb + Lc / Tc) / 3.

[0026] The flat magnetic metal particles preferably have a coercive force difference depending on the direction within the flat surface. The larger the directional coercive force difference, the better, and it is preferably 1% or more. More preferably, the coercive force difference is 10% or more, even more preferably 50% or more, and even more preferably 100% or more. The coercive force difference ratio here is defined as (Hc(max)-Hc(min)) / Hc(min)×100(%), where Hc(max) is the maximum coercive force and Hc(min) is the minimum coercive force within the flat surface. Note that coercive force can be evaluated using a vibrating sample magnetometer (VSM) or the like. When the coercive force is low, a coercive force of 0.1 Oe or less can be measured by using a low magnetic field unit. Measurements are performed by changing the direction within the flat surface relative to the direction of the measurement magnetic field.

[0027] The phrase "having a coercive force difference" means that when a magnetic field is applied in a 360-degree direction within the flat surface and the coercive force is measured, there is a direction in which the coercive force is maximized and a direction in which the coercive force is minimized. For example, when the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the flat surface, if a coercive force difference is observed, i.e., there is an angle where the coercive force is greater and an angle where the coercive force is smaller, the particle is considered to have a coercive force difference. Figure 4 is a schematic diagram showing the direction in which the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the flat surface in the flat magnetic metal particle of the first embodiment. Note that Figure 4 illustrates the flat surface of the flat magnetic metal particle as viewed from above. Having a coercive force difference within the flat surface is preferable because it reduces the minimum coercive force value compared to an isotropic case where there is almost no coercive force difference. In materials that have magnetic anisotropy in the flat plane, the coercive force varies depending on the direction in the flat plane, and the minimum coercive force value is smaller than that of magnetically isotropic materials. This reduces hysteresis loss and improves magnetic permeability, which is preferable.

[0028] Coercivity, in relation to magnetocrystalline anisotropy, is sometimes discussed using the approximate formula Hc = αHa-NMs (Hc: coercivity, Ha: magnetocrystalline anisotropy, Ms: saturation magnetization, α and N: values ​​that vary depending on the composition, structure, shape, etc.). In other words, generally, the larger the magnetocrystalline anisotropy, the greater the coercivity tends to be, and the smaller the magnetocrystalline anisotropy, the smaller the coercivity tends to be. However, the α and N values ​​in the above approximate formula vary greatly depending on the material's composition, structure, and shape. Even if the magnetocrystalline anisotropy is large, the coercivity may be relatively small (when the α value is small or the N value is large), or even if the magnetocrystalline anisotropy is small (when the α value is large or the N value is small), the coercivity may be relatively large. While magnetocrystalline anisotropy is an inherent property of a material that is determined by its composition, coercivity is a property that is not determined solely by the material's composition but can vary greatly depending on its structure, shape, etc. Furthermore, while magnetocrystalline anisotropy is a factor that does not directly affect hysteresis loss but rather indirectly, coercivity is a factor that directly affects the loop area of ​​the DC magnetization curve (this area corresponds to the magnitude of hysteresis loss), and therefore is a factor that almost directly determines the magnitude of hysteresis loss. In other words, unlike magnetocrystalline anisotropy, coercivity can be said to be a very important factor that directly and significantly affects hysteresis loss.

[0029] Furthermore, just because flat magnetic metal particles have magnetic anisotropy, including magnetocrystalline anisotropy, it does not necessarily mean that a difference in coercivity will occur depending on the direction of the flat surface of the flat magnetic metal particles. As mentioned above, coercivity is not a value uniquely determined by magnetocrystalline anisotropy, but is a property that can change in various ways depending on the composition, structure, and shape of the material. And, as mentioned above, the factor that directly and significantly affects hysteresis loss is coercivity, not magnetic anisotropy. From the above, a very desirable condition for improving performance is "having a difference in coercivity depending on the direction within the flat surface." This reduces hysteresis loss and increases magnetic permeability, which is desirable.

[0030] The ratio a / b of the maximum length a to the minimum length b within the flat surface is preferably 2 or more, more preferably 3 or more, even more preferably 5 or more, and even more preferably 10 or more. It is preferable to include those in which the ratio a / b of the maximum length a to the minimum length b within the flat surface is 2 or more, even more preferably 3 or more, even more preferably 5 or more, and even more preferably 10 or more. This makes it easier to impart magnetic anisotropy, which is desirable. When magnetic anisotropy is imparted, a coercive force difference is created within the flat surface, and the minimum coercive force value is smaller than that of a magnetically isotropic material. This reduces hysteresis loss and improves magnetic permeability, which is desirable. It is more desirable that the first direction of one or both of the multiple recesses and multiple protrusions described below is aligned in the maximum length direction in the flat magnetic metal particles. Furthermore, when the flat magnetic metal particles are compacted, the large a / b of the flat magnetic metal particles increases the overlapping area (or area ratio) of the flat surfaces of individual flat magnetic metal particles, which increases the strength of the compact, which is desirable. Furthermore, a larger ratio of the maximum length to the minimum length is preferable because the magnetic moment is confined in a direction parallel to the flat surface, facilitating magnetization through rotational magnetization. When magnetization progresses through rotational magnetization, magnetization tends to progress reversibly, resulting in a smaller coercive force, which is preferable because hysteresis loss can be reduced. From the perspective of increasing strength, the ratio a / b of the maximum length a to the minimum length b within the flat surface is preferably greater than or equal to 1 and less than 2, more preferably greater than or equal to 1 and less than 1.5. This is desirable because it improves the fluidity and packing properties of the particles. Furthermore, compared to when a / b is large, the strength in the direction perpendicular to the flat surface is higher, which is preferable from the perspective of increasing the strength of the flat magnetic metal particles. Furthermore, the particles are less likely to bend during compaction, which reduces stress on the particles. In other words, strain is reduced, resulting in reduced coercive force and hysteresis loss, and stress is reduced, which in turn improves mechanical properties such as thermal stability, strength, and toughness.

[0031] Furthermore, it is preferable to use a flat surface having a contour shape with at least a corner on at least a portion thereof. For example, a contour shape such as a square or rectangle, in other words, a corner angle of approximately 90 degrees, is desirable. This reduces the symmetry of the atomic arrangement at the corners, constraining the electron orbits, which is desirable because it makes it easier to impart magnetic anisotropy within the flat surface.

[0032] On the other hand, from the viewpoint of reducing loss and increasing strength, it is desirable that the contour shape of the flat surface be formed by a rounded curve. As an extreme example, a rounded contour shape such as a circle or ellipse is desirable. This is desirable because it improves the wear resistance of the particles. It is also desirable because it makes it difficult for stress to concentrate around the contour shape, reducing the magnetic distortion of the flat magnetic metal particles, lowering the coercive force, and reducing hysteresis loss. Since stress concentration is reduced, it is also desirable because it makes it easier to improve mechanical properties such as thermal stability, strength, and toughness.

[0033] The flat magnetic metal particles preferably have a magnetic metal phase containing Fe, Co, and Si. This case will be explained in detail below. In the magnetic metal phase, the amount of Co is preferably 0.001 at% to 80 at% of the total amount of Fe and Co, more preferably 1 at% to 60 at% of the total amount of Fe and Co, even more preferably 5 at% to 40 at% of the total amount of Co, and even more preferably 10 at% to 20 at% of the total amount of Co. This is preferable because it makes it easy to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. In addition, Fe-Co systems are preferable because they easily achieve high saturation magnetization. Furthermore, by having the composition range of Fe and Co fall within the above range, it is preferable to achieve higher saturation magnetization. In addition, the amount of Si is preferably 0.001 at% to 30 at% of the total amount of the magnetic metal phase, more preferably 1 at% to 25 at% of the total amount of Co, and even more preferably 5 at% to 20 at% of the total amount of Si. This is preferable because it makes the magnetocrystalline anisotropy of an appropriate magnitude, makes it easy to reduce the coercive force, and makes it easy to achieve low hysteresis loss and high magnetic permeability.

[0034] Furthermore, when the magnetic metal phase is a system containing Fe, Co, and Si, and the Co and Si contents are within the above-mentioned ranges, the above-mentioned anisotropy-imparting effect is particularly significant. Compared to monoatomic systems containing only Fe or Co, or diatomic systems containing only Fe and Si, or only Fe and Co, a triatomic system containing Fe, Co, and Si is particularly likely to impart a moderately large magnetic anisotropy and reduce coercive force, thereby reducing hysteresis loss and improving magnetic permeability, which is preferable. This significant effect is particularly achieved only when the composition is within the above-mentioned range. Furthermore, when the composition is within the above-mentioned range in a triatomic system containing Fe, Co, and Si, thermal stability and oxidation resistance are also significantly improved, which is preferable. Furthermore, because thermal stability and oxidation resistance are improved, mechanical properties at high temperatures are also improved, which is preferable. Furthermore, mechanical properties at room temperature, such as strength, hardness, and wear resistance, are also improved, which is preferable. Furthermore, when synthesizing the flat magnetic metal particles, ribbons are synthesized by a roll quenching method or the like, and then the ribbons are pulverized to obtain flat magnetic metal particles. When the magnetic metal phase is a triatomic system of Fe, Co, and Si, and the Co and Si contents are each within the above ranges, the particles are particularly easily pulverized, which is preferable because it makes the flat magnetic metal particles relatively resistant to distortion. When flat magnetic metal particles are resistant to distortion, the coercive force is easily reduced, and low hysteresis loss and high magnetic permeability are easily achieved, which is preferable. Furthermore, low distortion is preferable because it improves stability over time, improves thermal stability, and provides excellent mechanical properties such as strength, hardness, and wear resistance.

[0035] The average crystal grain size of the magnetic metal phase is preferably 1 μm or more, more preferably 10 μm or more, even more preferably 50 μm or more, and even more preferably 100 μm or more. As the average crystal grain size of the magnetic metal phase increases, the proportion of the surface of the magnetic metal phase decreases, reducing the number of pinning sites, which in turn reduces the coercive force and hysteresis loss, which is preferable. Furthermore, when the average crystal grain size of the magnetic metal phase increases within the above range, it is easy to impart a moderately large magnetic anisotropy, which is preferable, improving the above-mentioned magnetic properties.

[0036] In particular, when the magnetic metal phase contains Fe, Co, and Si, and the Co and Si contents are each within the aforementioned ranges, and the average crystal grain size of the magnetic metal phase is within the aforementioned ranges, it is more preferable that the magnetic anisotropy is easily imparted with a moderately large value, and the above-mentioned magnetic properties are significantly improved. Among these, it is particularly preferable that the magnetic metal phase contains Fe, Co, and Si, and the Co content is 5 at% to 40 at% or less, more preferably 10 at% to 20 at% of the total amount of Fe and Co, and the Si content is 1 at% to 25 at% or less, more preferably 5 at% to 20 at% of the total amount of the magnetic metal phase, and the average crystal grain size of the magnetic metal phase is 10 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, because the magnetic anisotropy is easily imparted with a moderately large value, and the above-mentioned magnetic properties are significantly improved.

[0037] Furthermore, it is preferable that the magnetic metal phase has a portion having a body-centered cubic (bcc) crystal structure. This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. Furthermore, even if the magnetic metal phase has a "mixed phase crystal structure of bcc and fcc" that partially has a face-centered cubic (fcc) crystal structure, it is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties.

[0038] Furthermore, it is preferable that the flat surfaces of the flat magnetic metal particles are generally crystalline oriented. The orientation direction is preferably the (110) plane orientation. This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. A more preferable orientation direction is the (110)

[0111] direction. This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. It is preferable that the crystal planes of the flat surfaces of the flat magnetic metal particles have a peak intensity ratio of 10% or less, more preferably 5% or less, and even more preferably 3% or less, relative to (110) for crystal planes other than (110) and (220) (e.g., (200), (211), (310), (222), etc.) relative to (110) as measured by XRD (X-ray diffraction). This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties.

[0039] In order to orient the flat surfaces of the flat magnetic metal particles in the (110) orientation, it is effective to select appropriate heat treatment conditions. The heat treatment temperature is preferably set to 800°C or higher and 1200°C or lower, more preferably 850°C or higher and 1100°C or lower, even more preferably 900°C or higher and 1000°C or lower, and even more preferably 920°C or higher and 980°C or lower (preferably around 940°C). If the heat treatment temperature is too low or too high, the (110) orientation does not progress easily, and a heat treatment temperature within the above range is most preferable. The heat treatment time is preferably 10 minutes or longer, more preferably 1 hour or longer, and even more preferably about 4 hours. If the heat treatment time is too short or too long, the (110) orientation does not progress easily, and a heat treatment time of about 4 hours is most preferable. The heat treatment atmosphere is preferably a low-oxygen vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, and more preferably a reducing atmosphere such as H2 (hydrogen), CO (carbon monoxide), or CH4 (methane). This is preferable because it suppresses oxidation of the flat magnetic metal particles and reduces the oxidized portions. By selecting the above heat treatment conditions, the (110) orientation is facilitated, and it is possible for the peak intensity ratio of crystal planes other than (110) and (220) (e.g., (200), (211), (310), (222), etc.) to (110) measured by XRD (X-ray diffraction) to be 10% or less, further 5% or less, or even 3% or less. In addition, distortion can be appropriately removed, and a state in which oxidation is suppressed (a reduced state) can be achieved, which is preferable.

[0040] Furthermore, the flat magnetic metal particles preferably have a magnetic metal phase consisting of at least one first element selected from the group consisting of Fe, Co, and Ni and an additive element. This case will be explained in detail below. The additive element preferably includes B and Hf. Furthermore, the total amount of the additive elements is preferably 0.002 at% to 80 at% of the entire magnetic metal phase, more preferably 5 at% to 80 at% of the entire magnetic metal phase, even more preferably 5 at% to 40 at% of the entire magnetic metal phase, and even more preferably 10 at% to 40 at% of the entire magnetic metal phase. This is preferable because it promotes amorphization, makes it easier to impart magnetic anisotropy, and improves the above-mentioned magnetic properties. Furthermore, the amount of Hf is preferably 0.001 at% to 40 at% of the entire magnetic metal phase, more preferably 1 at% to 30 at% of the entire magnetic metal phase, even more preferably 1 at% to 20 at% of the entire magnetic metal phase, even more preferably 1 at% to 15 at% of the entire magnetic metal phase, and even more preferably 1 at% to 10 at% of the entire magnetic metal phase. This is preferable because it promotes amorphousness, makes it easier to impart magnetic anisotropy, and improves the above-mentioned magnetic properties.

[0041] Furthermore, when the magnetic metal phase contains the first element and the additional elements B and Hf, and the total amount of the additional elements and the amount of Hf are within the above-mentioned ranges, the above-mentioned anisotropy-imparting effect is particularly significant. This significant effect is only achieved when the composition is within the above-mentioned range. Furthermore, compared to systems containing other additional elements, systems containing Hf, in particular, are more likely to undergo amorphous formation with a small amount, which makes it easier to impart magnetic anisotropy and achieve both high saturation magnetization, which is preferable. Furthermore, Hf has a high melting point, and when contained in the magnetic metal phase in the above-mentioned amount range, thermal stability and oxidation resistance are significantly improved, which is preferable. Furthermore, because thermal stability and oxidation resistance are improved, mechanical properties at high temperatures are also improved, which is preferable. Furthermore, mechanical properties at room temperature, such as strength, hardness, and wear resistance, are also improved, which is preferable. Furthermore, when synthesizing the flat magnetic metal particles, ribbons are synthesized by a roll quenching method or the like, and then the ribbons are pulverized to obtain flat magnetic metal particles. When the magnetic metal phase is a system containing the first element and the additional elements B and Hf, and the total amount of the additional elements and the amount of Hf are within the above ranges, the particles are particularly easily pulverized, which is preferable because it makes it relatively difficult for distortion to occur in the flat magnetic metal particles. When flat magnetic metal particles are less susceptible to distortion, the coercive force is easily reduced, and low hysteresis loss and high magnetic permeability are easily achieved, which is preferable. Furthermore, low distortion is preferable because it improves stability over time, improves thermal stability, and provides excellent mechanical properties such as strength, hardness, and wear resistance.

[0042] Furthermore, when the magnetic metal phase is a system containing the first element and the additional elements B and Hf, and the total amount of the additional elements and the amount of Hf are within the above ranges, the thermal stability is excellent, making it possible to set the optimal heat treatment conditions for the flat magnetic metal particles at a high level. That is, in the method for producing flat magnetic metal particles, ribbons are synthesized, the resulting ribbons are heat-treated (or not) and crushed, and then heat-treated to remove distortion (more preferably, heat treatment in a magnetic field is preferred). This allows the heat treatment temperature to be set relatively high. This makes it easier to release distortion and realize a low-loss material with little distortion. For example, heat treatment at 500°C or higher makes it easier to realize a low-loss material (low-loss can be achieved at a higher heat treatment temperature than with other systems and compositions; for example, the optimal heat treatment temperature for other systems and compositions is around 400°C).

[0043] The additive elements preferably include one or more "different elements" in addition to B and Hf. Examples of the "different elements" include C, Ta, W, P, N, Mg, Al, Si, Ca, Zr, Ti, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Nb, Pb, Cu, In, Sn, and rare earth elements. Among these, rare earth elements are more preferred, and Y is even more preferred. The inclusion of "different elements" effectively suppresses the diffusion of elements contained in the magnetic metal phase, promotes amorphization, and facilitates the impartation of magnetic anisotropy, which is more preferable (facilitating the realization of low coercivity, low hysteresis loss, and high magnetic permeability). In particular, the "different elements" have an atomic radius different from that of B and Hf, which effectively suppresses the diffusion of elements contained in the magnetic metal phase. For example, Y has a larger atomic radius than B and Hf, and therefore can very effectively suppress the diffusion of elements contained in the magnetic metal phase. Below, we will explain the appropriate composition range using the example where the "other different element" is Y. The amount of Y is preferably 1 at% to 80 at% of the total amount of Hf and Y, more preferably 2 at% to 60 at% and even more preferably 4 at% to 60 at%. Furthermore, the total amount of Hf and Y is preferably 0.002 at% to 40 at% of the entire magnetic metal phase, more preferably 1 at% to 30 at% and even more preferably 1 at% to 20 at% and even more preferably 1 at% to 15 at% and even more preferably 1 at% to 10 at%. This promotes amorphization, facilitates the impartation of magnetic anisotropy, and improves the above-mentioned magnetic properties. By falling within the above composition range, a significantly greater effect is exhibited, particularly with regard to the anisotropy imparting effect, compared to when the added elements are only B and Hf. This significantly greater effect is only achieved when the composition falls within the above composition range. Furthermore, even a small amount of Y facilitates amorphization, making it easy to impart magnetic anisotropy and simultaneously achieve high saturation magnetization, making it preferable. By appropriately selecting the composition of a system with Y added, it is possible to realize properties that cannot be achieved with a BHf system.In addition, the thermal stability and oxidation resistance are remarkably improved, which is preferable. Furthermore, because the thermal stability and oxidation resistance are improved, the mechanical properties at high temperatures are also improved, which is preferable. Furthermore, the mechanical properties at room temperature, such as strength, hardness, and wear resistance, are also improved, which is preferable.

[0044] Furthermore, the average crystal grain size of the magnetic metal phase is preferably 100 nm or less, more preferably 50 nm or less, even more preferably 20 nm or less, and even more preferably 10 nm or less. The smaller the grain size, the better, with 5 nm or less being more preferable, and 2 nm or less being even more preferable. This is preferable because it makes it easier to impart anisotropy and improves the above-mentioned magnetic properties. Furthermore, since a small crystal grain size means that the phase is closer to amorphous, the electrical resistance is higher than that of highly crystalline phases, which is preferable because it makes it easier to reduce eddy current loss. Furthermore, it is preferable because it has superior corrosion resistance and oxidation resistance compared to highly crystalline phases.

[0045] In addition, when the additive element includes one or more "other different elements (e.g., Y)" in addition to B and Hf, and the amount of the "other different elements (e.g., Y)" and the total amount of Hf and the "other different elements (e.g., Y)" are within the above-mentioned ranges, an average crystal grain size of 30 nm or less can be achieved relatively easily, which is preferable. In other words, since it is closer to an amorphous state, the electrical resistance is higher than that of highly crystalline materials, which makes it easier to reduce eddy current loss, which is preferable. In addition, it is preferable because it has superior corrosion resistance and oxidation resistance compared to highly crystalline materials. In addition, it is preferable because it is easier to impart anisotropy, which improves the above-mentioned magnetic properties.

[0046] In particular, when the magnetic metal phase is a system containing the first element and B and Hf as the additional elements, and the total amount of the additional elements and the amount of Hf are each within the above ranges, and the average crystal grain size of the magnetic metal phase is within the above ranges, the magnetic properties are improved by the effect of imparting magnetic anisotropy, and the effects of increasing electrical resistance (reducing eddy current loss) by becoming amorphous, as well as high corrosion resistance and high oxidation resistance are significantly improved, making this more preferable. Among these, it is particularly preferable that the magnetic metal phase is a system containing the first element and B and Hf as the additional elements, and the total amount of the additional elements is 5 at% or more and 40 at% or less, more preferably 10 at% or more and 40 at% or less, of the entire magnetic metal phase, the amount of Hf is 1 at% or more and 20 at% or less, more preferably 1 at% or more and 15 at% or less, even more preferably 1 at% or more and 10 at% or less, of the entire magnetic metal phase, and the average crystal grain size of the magnetic metal phase is 50 nm or less, more preferably 20 nm or less, even more preferably 10 nm or less, because this significantly improves the magnetic properties due to the effect of imparting magnetic anisotropy, increases the electrical resistance due to amorphization (reduction of eddy current loss), and improves the effects of high corrosion resistance and high oxidation resistance.

[0047] Note that crystal grain sizes of 100 nm or less can be easily calculated using the Scherrer formula based on XRD measurements, and can also be determined by observing a large number of magnetic metal phases using a TEM (Transmission Electron Microscope) and averaging their grain sizes. When the crystal grain size is small, it is preferable to determine it using XRD measurements, and when the crystal grain size is large, it is preferable to determine it using TEM observations. However, it is preferable to select a measurement method depending on the situation, or to use both methods in combination to make a comprehensive judgment.

[0048] The flat magnetic metal particles preferably have a high saturation magnetization, preferably 1 T or higher, more preferably 1.5 T or higher, even more preferably 1.8 T or higher, and even more preferably 2.0 T or higher. This suppresses magnetic saturation and allows the magnetic properties of the system to be fully utilized. However, depending on the application (e.g., magnetic wedges in motors), a relatively low saturation magnetization may be sufficient, and in fact, specializing in low loss may be preferable. Note that the magnetic wedge in a motor is like a cover for the slot into which the coil is inserted. While nonmagnetic wedges are typically used, the use of magnetic wedges reduces the density variation in magnetic flux density, reduces harmonic loss, and improves motor efficiency. In this case, a high saturation magnetization of the magnetic wedge is preferable, but even a relatively low saturation magnetization can be effective. Therefore, it is important to select the composition according to the application.

[0049] The lattice distortion of the flat magnetic metal particles is preferably 0.01% to 10%, more preferably 0.01% to 5%, even more preferably 0.01% to 1%, and even more preferably 0.01% to 0.5%, which is preferred because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties.

[0050] The lattice strain can be calculated by detailed analysis of the line width obtained by X-ray diffraction (XRD). That is, by performing a Halder-Wagner plot or a Hall-Williamson plot, the contribution of the line width broadening can be separated into the crystal grain size and the lattice strain. This allows the lattice strain to be calculated. The Halder-Wagner plot is preferable from the viewpoint of reliability. For details about the Halder-Wagner plot, see, for example, NC Halder, CNJ Wagner, Acta Cryst. 20 (1966) 312-313. Here, the Halder-Wagner plot is expressed by the following formula:

number

[0051] In other words, the vertical axis is β 2 / tan 2 The grain size D is calculated from the slope of the approximate straight line, and the lattice strain ε is calculated from the intercept on the vertical axis. When the lattice strain (root mean square) according to the Halder-Wagner plot of the above formula is 0.01% to 10%, more preferably 0.01% to 5%, even more preferably 0.01% to 1%, and even more preferably 0.01% to 0.5%, it is easy to impart a moderately large magnetic anisotropy, and the above-mentioned magnetic properties are improved, which is preferable.

[0052] The lattice strain analysis described above is effective when multiple peaks can be detected by XRD. However, analysis is difficult when the peak intensity is weak and only a single peak can be detected (e.g., only one peak is detected). In such cases, it is preferable to calculate the lattice strain using the following procedure. First, the composition is determined using inductively coupled plasma (ICP) emission spectroscopy or energy dispersive X-ray spectroscopy (EDX), and the composition ratios of the three magnetic metal elements Fe, Co, and Ni are calculated. (If there are only two magnetic metal elements, two composition ratios are used. If there is only one magnetic metal element, one composition ratio (=100%) is used.) Next, the ideal lattice spacing d0 is calculated from the Fe-Co-Ni composition (see literature values, etc.; in some cases, an alloy with that composition is prepared and the lattice spacing is measured). The amount of strain can then be determined by calculating the difference between the lattice spacing d of the measured sample peak and the ideal lattice spacing d0. In other words, in this case, the amount of strain is calculated as (d-d0) / d0 x 100(%). As mentioned above, it is preferable to use the above two methods for analyzing lattice strain depending on the state of peak intensity, and in some cases to use both methods in combination.

[0053] The lattice spacing in the flat plane varies depending on the direction, and the maximum lattice spacing d max and the minimum lattice spacing d min The percentage difference (=(d max -d min ) / d min × 100(%)) is preferably 0.01% or more and 10% or less, more preferably 0.01% or more and 5% or less, even more preferably 0.01% or more and 1% or less, and even more preferably 0.01% or more and 0.5% or less. This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. The lattice spacing can be easily determined by XRD measurement. By performing this XRD measurement while changing the direction within the plane, the difference in lattice constant depending on the direction can be determined.

[0054] The crystallites of the flat magnetic metal particles are preferably either stringed together in one direction within the flat surface, or rod-shaped and oriented in one direction within the flat surface, which is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties.

[0055] The flat surfaces of the flat magnetic metal particles preferably have one or both of a plurality of recesses and a plurality of protrusions arranged in a first direction, each having a width of 0.1 μm or more, a length of 1 μm or more, and an aspect ratio of 2 or more. This makes it easier to induce magnetic anisotropy in the first direction, and increases the difference in coercivity depending on the direction within the flat surfaces, which is preferable. From this perspective, it is even more preferable that the width is 1 μm or more and the length is 10 μm or more. The aspect ratio is preferably 5 or more, and even more preferably 10 or more. Furthermore, by providing such recesses or protrusions, the adhesion between the flat magnetic metal particles is improved when the flat magnetic metal particles are compressed to synthesize a compressed powder material (the recesses or protrusions have an anchoring effect that bonds the particles together), which is preferable because it improves mechanical properties such as strength and hardness, as well as thermal stability.

[0056] FIG. 5 is a perspective schematic diagram of a flat magnetic metal particle according to the first embodiment. Note that only recesses are provided in the upper diagram of FIG. 5, and only protrusions are provided in the central diagram of FIG. 5. However, as shown in the lower diagram of FIG. 5, a single flat magnetic metal particle may have both recesses and protrusions. FIG. 6 is a schematic diagram of a flat magnetic metal particle according to the first embodiment as viewed from above. Note that FIG. 6 illustrates the flat surface of the flat magnetic metal particle as viewed from above. The width and length of the recesses or protrusions and the distance between the recesses or protrusions are shown. A single flat magnetic metal particle may have both recesses and protrusions. Note that the aspect ratio of a recess or protrusion is the length of the major axis / the length of the minor axis. In other words, when the length of a recess or protrusion is greater (longer) than the width, the aspect ratio is defined as length / width, and when the width is greater (longer) than the length, the aspect ratio is defined as width / length. A larger aspect ratio is more likely to have magnetic uniaxial anisotropy (anisotropy), and is therefore more preferable. In FIG. 6, recesses 2a, protrusions 2b, flat surfaces 6, and flat magnetic metal particles 10 are shown.

[0057] Furthermore, "aligned in the first direction" refers to the longer of the length and width of the recesses or protrusions being aligned parallel to the first direction. Note that if the longer of the length and width of the recesses or protrusions is aligned within ±30 degrees of a direction parallel to the first direction, it is considered "aligned in the first direction." This favorably allows the flat magnetic metal particles to have uniaxial magnetic anisotropy in the first direction due to the effect of shape magnetic anisotropy. It is preferable that flat magnetic metal particles have magnetic anisotropy in one direction within the flat plane, which will be explained in more detail below. First, when the magnetic domain structure of the flat magnetic metal particles is a multi-domain structure, the magnetization process proceeds by domain wall motion. In this case, the coercive force is smaller in the easy axis direction than in the hard axis direction within the flat plane, resulting in reduced loss (hysteresis loss). Furthermore, the magnetic permeability is greater in the easy axis direction than in the hard axis direction. Compared to isotropic flat magnetic metal particles, flat magnetic metal particles with magnetic anisotropy are preferred because they have a smaller coercive force, especially in the easy axis direction, thereby reducing loss. The magnetic permeability is also increased, which is desirable. In other words, having magnetic anisotropy in the in-plane direction improves the magnetic properties compared to isotropic materials. In particular, the magnetic properties are superior in the easy axis direction in the flat plane compared to the hard axis direction, which is desirable. Next, when the magnetic domain structure of the flat magnetic metal particle is a single domain structure, the magnetization process proceeds by rotational magnetization. In this case, the coercive force is smaller in the hard axis direction in the flat plane than in the easy axis direction, and loss is reduced. When magnetization proceeds completely by rotational magnetization, the coercive force becomes zero, and hysteresis loss becomes zero, which is desirable. Note that whether magnetization proceeds by domain wall motion (domain wall motion type) or rotational magnetization (rotational magnetization type) is determined by whether the magnetic domain structure is a multi-domain structure or a single-domain structure. In this case, whether it is a multi-domain structure or a single-domain structure is determined by the size (thickness and aspect ratio) of the flat magnetic metal particle, composition, the state of interaction between particles, etc. For example, the smaller the thickness t of the flat magnetic metal particle, the more likely it is to have a single magnetic domain structure. When the thickness is 10 nm or more and 1 μm or less, particularly when it is 10 nm or more and 100 nm or less, the single magnetic domain structure is more likely to be formed.In terms of composition, compositions with high magnetic crystal anisotropy tend to maintain a single magnetic domain structure even at high thicknesses, while compositions with low magnetic crystal anisotropy tend to have difficulty maintaining a single magnetic domain structure unless the thickness is small. In other words, the thickness at which the boundary between a single magnetic domain structure and a multi-domain structure changes depending on the composition. Furthermore, when the flat magnetic metal particles are magnetically coupled to each other and the magnetic domain structure is stabilized, a single magnetic domain structure is more likely to occur. Whether the magnetization behavior is domain wall motion or rotational magnetization can be easily determined as follows: First, magnetization measurements are performed in the material plane (a plane parallel to the flat surfaces of the flat magnetic metal particles) by changing the direction of the applied magnetic field, and the two directions (these directions are 90 degrees apart) that produce the greatest difference in the magnetization curves are identified. Next, by comparing the curves for the two directions, it is possible to determine whether the magnetization behavior is domain wall motion or rotational magnetization.

[0058] As described above, it is preferable that the flat magnetic metal particles have magnetic anisotropy in one direction within the flat surface. However, it is more preferable that the flat magnetic metal particles are arranged in a first direction and have one or both of a plurality of recesses and a plurality of protrusions with a width of 0.1 μm or more, a length of 1 μm or more, and an aspect ratio of 2 or more, which makes it easier to induce magnetic anisotropy in the first direction. From this perspective, a width of 1 μm or more and a length of 10 μm or more are even more preferable. The aspect ratio is preferably 5 or more, and even more preferably 10 or more. Furthermore, by providing such recesses or protrusions, the adhesion between the flat magnetic metal particles is improved when the flat magnetic metal particles are compressed to synthesize a compressed powder material (the recesses or protrusions have an anchoring effect that bonds the particles together), which is preferable because it improves mechanical properties such as strength and hardness, as well as thermal stability.

[0059] Furthermore, in the flat magnetic metal particles, it is preferable that the first direction of one or both of the most numerous recesses and protrusions is aligned in the direction of the easy axis of magnetization. In other words, when there are numerous alignment directions (= first directions) within the flat surface of the flat magnetic metal particle, it is preferable that the most numerous alignment direction (= first direction) among the numerous alignment directions (= first directions) coincides with the easy axis direction of the flat magnetic metal particle. Because the length direction in which the recesses or protrusions are aligned, i.e., the first direction, tends to become the easy axis of magnetization due to the effect of shape magnetic anisotropy, it is preferable to align this direction as the easy axis of magnetization, as this makes it easier to impart magnetic anisotropy.

[0060] It is desirable that an average of five or more recesses and / or multiple protrusions are contained in one flat magnetic metal particle. Here, five or more recesses or five or more protrusions may be contained, or the sum of the number of recesses and the number of protrusions may be five or more. It is even more desirable that ten or more recesses or protrusions are contained. It is also desirable that the average distance in the width direction between each recess or protrusion is 0.1 μm or more and 100 μm or less. Furthermore, it is desirable that multiple metal deposits containing at least one first element selected from the group consisting of Fe, Co, and Ni and having an average size of 1 nm or more and 1 μm or less are arranged along the recesses or protrusions. The average size of the metal deposits is determined by averaging the sizes of the multiple metal deposits arranged along the recesses or protrusions based on observation using a TEM, SEM, optical microscope, or the like. Satisfying these conditions is preferable because it facilitates the induction of magnetic anisotropy in one direction. In addition, when the flat magnetic metal particles are compressed to synthesize the compressed powder material, the adhesion between the flat magnetic metal particles is improved (the recesses or protrusions have an anchoring effect that bonds the particles together), which is preferable because it improves mechanical properties such as strength and hardness, as well as thermal stability.

[0061] It is desirable that the flat magnetic metal particles further comprise a plurality of magnetic metal small particles, an average of five or more, on the flat surfaces. The magnetic metal small particles contain at least one first element selected from the group consisting of Fe, Co, and Ni, and have an average particle size of 10 nm to 1 μm. More preferably, the magnetic metal small particles have the same composition as the flat magnetic metal particles. By providing the magnetic metal small particles on the surface of the flat surfaces or integrating the magnetic metal small particles with the flat magnetic metal particles, the surfaces of the flat magnetic metal particles become slightly roughened, which greatly improves adhesion when the flat magnetic metal particles are compacted with the intervening phase described below. This facilitates improvements in mechanical properties such as thermal stability, strength, and toughness. To maximize this effect, it is desirable that the average particle size of the magnetic metal small particles be 10 nm to 1 μm, and that an average of five or more magnetic metal small particles be integrated on the surface, i.e., the flat surfaces, of the flat magnetic metal particles. It is more preferable to arrange the small magnetic metal particles in one direction within the flat surface, as this makes it easier to impart magnetic anisotropy within the flat surface and makes it easier to achieve high magnetic permeability and low loss. The average particle size of the small magnetic metal particles can be determined by observation using a TEM, SEM, optical microscope, or the like.

[0062] The particle size distribution variation of flat magnetic metal particles can be defined by the coefficient of variation (CV value). That is, CV value (%) = [standard deviation of particle size distribution (μm) / average particle size (μm)] × 100. The smaller the CV value, the smaller the particle size distribution variation and the sharper the particle size distribution. When the CV value as defined above is 0.1% or more and 60% or less, low coercivity, low hysteresis loss, high magnetic permeability, and high thermal stability can be achieved, which is preferable. Furthermore, because the variation is small, high yields can be easily achieved. A more preferable CV value range is 0.1% or more and 40% or less.

[0063] One effective method for imparting a directional difference in coercivity within the flat surfaces of flat magnetic metal particles is heat treatment in a magnetic field. It is desirable to perform the heat treatment while applying a magnetic field in one direction within the flat surfaces. Before performing the heat treatment in a magnetic field, it is desirable to identify the easy axis direction within the flat surfaces (the direction with the smallest coercivity), and then perform the heat treatment while applying a magnetic field in that direction. The stronger the applied magnetic field, the better, but it is preferable to apply 1 kOe or more, and even more preferable to apply 10 kOe or more. This is preferable because it can induce magnetic anisotropy within the flat surfaces of the flat magnetic metal particles, impart a directional difference in coercivity, and achieve excellent magnetic properties. Heat treatment is preferably performed at a temperature of 50°C or higher and 800°C or lower. The heat treatment atmosphere is preferably a low-oxygen vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, and more preferably a reducing atmosphere such as H2 (hydrogen), CO (carbon monoxide), or CH4 (methane). The reason for this is that even if the flat magnetic metal particles are oxidized, heat treatment in a reducing atmosphere can reduce the oxidized metal and return them to metal. This can also reduce flat magnetic metal particles that have been oxidized and have reduced saturation magnetization, restoring the saturation magnetization. Note that if heat treatment significantly crystallizes the flat magnetic metal particles, their properties will deteriorate (increased coercive force and decreased magnetic permeability), so it is preferable to select conditions that suppress excessive crystallization.

[0064] Furthermore, when synthesizing flat magnetic metal particles, if ribbons are synthesized by a roll quenching method or the like and then the ribbons are pulverized to obtain flat magnetic metal particles, one or both of the multiple recesses and multiple protrusions are likely to be aligned in the first direction during ribbon synthesis (the recesses and protrusions are likely to be aligned in the direction of roll rotation), which makes it easier to have a directional difference in coercivity within the flat surface, which is preferable. In other words, the direction in which one or both of the multiple recesses and multiple protrusions within the flat surface are aligned in the first direction is likely to be the direction of the easy magnetization axis, which makes it easier to effectively impart a directional difference in coercivity within the flat surface, which is preferable.

[0065] According to this embodiment, it is possible to provide flat magnetic metal particles having excellent magnetic properties such as low magnetic loss.

[0066] (Second embodiment) The multiple flat magnetic metal particles of this embodiment differ from the first embodiment in that at least a portion of the surface of the flat magnetic metal particles is covered with a coating layer having a thickness of 0.1 nm or more and 1 μm or less and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F).

[0067] It should be noted that descriptions that overlap with those in the first embodiment will be omitted.

[0068] 7 is a schematic diagram of a flat magnetic metal particle according to the second embodiment, showing a coating layer 9.

[0069] The coating layer preferably contains at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements, and at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). From the viewpoint of thermal stability, Al and Si are particularly preferred as non-magnetic metals. When the flat magnetic metal particles contain at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements, the coating layer preferably contains at least one non-magnetic metal that is the same as the non-magnetic metal that is one of the components of the flat magnetic metal particles. Among oxygen (O), carbon (C), nitrogen (N), and fluorine (F), it is preferable to contain oxygen (O), and it is preferable to use an oxide or a composite oxide. The above is from the viewpoint of ease of coating layer formation, oxidation resistance, and thermal stability. This improves the adhesion between the flat magnetic metal particles and the coating layer, making it possible to improve the thermal stability and oxidation resistance of the compacted powder material described below. The coating layer not only improves the thermal stability and oxidation resistance of the flat magnetic metal particles, but also improves the electrical resistance of the flat magnetic metal particles. Increasing the electrical resistance suppresses eddy current loss and improves the frequency characteristics of magnetic permeability. For this reason, it is preferable that the coating layer 14 have high electrical resistance, for example, a resistance value of 1 mΩ·cm or more.

[0070] The presence of a coating layer is also preferable from a magnetic standpoint. Because the thickness of flat magnetic metal particles is small compared to the size of the flat surfaces, they can be considered as a pseudo-thin film. In this case, the coating layer formed on the surface of the flat magnetic metal particles and integrated can be considered as a pseudo-laminated thin film structure, and the magnetic domain structure is energetically stabilized. This makes it possible to reduce the coercive force (thereby reducing hysteresis loss), which is preferable. At this time, the magnetic permeability also increases, which is preferable. From this standpoint, it is more preferable that the coating layer is non-magnetic (this makes it easier to stabilize the magnetic domain structure).

[0071] The thicker the coating layer, the better from the standpoints of thermal stability, oxidation resistance, and electrical resistance. However, if the coating layer is too thick, the saturation magnetization decreases, which also reduces the magnetic permeability, which is undesirable. Also, from a magnetic standpoint, if the thickness is too thick, the "effect of stabilizing the magnetic domain structure to achieve low coercivity, low loss, and high magnetic permeability" is reduced. Taking these factors into consideration, the preferred coating layer thickness is between 0.1 nm and 1 μm, and more preferably between 0.1 nm and 100 μm.

[0072] As described above, according to this embodiment, it is possible to provide flat magnetic metal particles having excellent properties such as high magnetic permeability, low loss, excellent mechanical properties, and high thermal stability.

[0073] (Third embodiment)

[0074] The pressed powder material of this embodiment has a flat surface and a magnetic metal phase containing Fe, Co, and Si, wherein the amount of Co is 0.001 at% or more and 80 at% or less of the total amount of Fe and Co, the amount of Si is 0.001 at% or more and 30 at% or less of the entire magnetic metal phase, the average thickness is 10 nm or more and 100 μm or less, and the average value of the ratio of the average length within the flat surface to the thickness is 5 or more and 10,000 or less, and an intervening phase present between the flat magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F), and the pressed powder material has a difference in coercivity depending on the direction within the plane of the pressed powder material.

[0075] In addition, the pressed powder material of this embodiment has a flat surface and a magnetic metal phase consisting of at least one first element selected from the group consisting of Fe, Co, and Ni and an additive element, wherein the additive element includes B and Hf, the total amount of the additive element is 0.002 at% or more and 80 at% or less of the entire magnetic metal phase, the average thickness is 10 nm or more and 100 μm or less, and the average value of the ratio of the average length within the flat surface to the thickness is 5 or more and 10,000 or less, and an intervening phase present between the flat magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F), and is a pressed powder material having a difference in coercivity depending on the direction within the plane.

[0076] The composition, average crystal grain size, and crystal orientation (generally (110) orientation) of the magnetic metal phase preferably satisfy the requirements described in the first embodiment, but a description of the details will be omitted here to avoid redundancy. An example of the compacted powder material is a compacted powder material obtained by compression molding the flat magnetic metal particles described in the first or second embodiment.

[0077] Furthermore, the saturation magnetization of the compacted powder material is preferably high, preferably 0.2 T or higher, more preferably 0.5 T or higher, 1.0 T or higher, even more preferably 1.8 T or higher, and even more preferably 2.0 T or higher. This suppresses magnetic saturation and allows the magnetic properties to be fully exhibited in the system, which is desirable. However, depending on the application (e.g., magnetic wedges in motors), a relatively low saturation magnetization may be sufficient, and in some cases, it may be preferable to specialize in low loss. Therefore, it is important to select the composition according to the application.

[0078] Fig. 8 is a schematic diagram of a compacted powder material according to the third embodiment. Illustrated are an intervening phase 20, a compacted powder material 100, and a plane 102 of the compacted powder material. The diagram on the right of Fig. 8 is a schematic diagram in which the hatching has been removed from the diagram on the left of Fig. 8 to make the intervening phase easier to see.

[0079] An example of the predetermined cross sections 22a and 22b is shown on the right side of Figure 8. In this embodiment, the flat surface 6 is oriented parallel to a plane 102 of the compacted powder material. The "predetermined cross section 22" is a cross section of the compacted powder material 100 that is perpendicular to this plane 102. Of course, the way in which the "predetermined cross section 22" is taken is not limited to that specified in Figure 8.

[0080] FIG. 9 is a schematic diagram showing an example of the arrangement of flat magnetic metal particles in a plane parallel to each cross section in the third embodiment. The pressed powder material 100 shown as an example in FIG. 9 has a rectangular parallelepiped shape with a vertical length a, a horizontal length b, and a height c. In FIG. 9, the plane 102 of the pressed powder material is assumed to be the upper surface (or lower surface) of the pressed powder material 100. In this case, the flat magnetic metal particles 10 are oriented parallel to the plane 102 (ab-plane) of the pressed powder material, so the arrangement of the flat magnetic metal particles 10 is, for example, as shown in the lower diagram of FIG. 9 (note that in the case of FIG. 9, elongated flat magnetic metal particles are used in which the ratio a / b of the maximum length a to the minimum length b within the flat plane of the flat magnetic metal particles is large). The plane perpendicular to the ab-plane is the "predetermined cross section." For example, a plane parallel to the bc plane or a plane parallel to the ac plane can be the "predetermined cross section" (otherwise, a plane perpendicular to the ab plane can be arbitrarily determined, and that plane can be the "predetermined cross section"). However, the way in which the "plane of the compacted powder material" and the "predetermined cross section" are determined is not limited to this.

[0081] It is defined that the closer the angle between the plane parallel to the flat surface of the flat magnetic metal particle and the plane of the compressed powder material is to 0 degrees, the more oriented the particle is. Figure 10 is a schematic diagram showing the angle between the plane parallel to the flat surface of the flat magnetic metal particle and the plane of the compressed powder material in the third embodiment. The above angle is determined for 100 flat magnetic metal particles, and the variation in orientation is preferably 30 degrees or more and 45 degrees or less, more preferably 35 degrees or more and 45 degrees or less, and even more preferably 40 degrees or more and 45 degrees or less. Here, for example, "orientation variation is 30 degrees or more and 45 degrees or less" means that "when the angle formed by the plane parallel to the flat surface of each flat magnetic metal particle and the plane of the compressed powder material is θ (rad), for each flat magnetic metal particle, a vector with a length of 1 and an angle of θ is used, and the resultant vector obtained by combining all the flat magnetic metal particles is divided by the number of flat magnetic metal particles to form an "average vector," and the length of the average vector is R, then S = (-2ln(R)) 0.5×π / 180 is 30 degrees or more and 45 degrees or less. That is, in the compacted powder material, it is preferable that the flat surfaces of the plurality of flat magnetic metal particles are arranged in a direction with a certain degree of orientation variation or more. This is preferable because, when a magnetic field perpendicular to the plane of the compacted powder material is applied, the eddy current loss of the compacted powder material can be reduced. Furthermore, since the demagnetizing field can be reduced, the magnetic permeability of the compacted powder material can be increased, which is preferable. Furthermore, since the ferromagnetic resonance frequency can be increased, the ferromagnetic resonance loss can be reduced, which is preferable. Furthermore, in such a structure, the magnetic domain structure is stabilized, which enables low magnetic loss to be achieved, which is preferable. On the other hand, since the flat magnetic metal particles are arranged at various orientation angles due to the orientation variation, a decrease in strength can be prevented, which is preferable.

[0082] When measuring the coercive force depending on the direction within the plane of the pressed powder material (within a plane parallel to the flat surface of the flat magnetic metal particles), for example, the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the plane.

[0083] By having a coercive force difference within the plane of the compacted powder material, the minimum coercive force value becomes smaller than in the case of an isotropic material with almost no coercive force difference, which is preferable. In a material with magnetic anisotropy within the plane, the coercive force varies depending on the direction within the plane, and the minimum coercive force value becomes smaller than in a magnetically isotropic material. This reduces hysteresis loss and improves magnetic permeability, which is preferable.

[0084] Within the plane of the compacted powder material (within a plane parallel to the flat surface of the flat magnetic metal particles), the larger the directional coercivity difference ratio, the better, and it is preferably 1% or more. More preferably, the coercivity difference ratio is 10% or more, even more preferably, the coercivity difference ratio is 50% or more, and even more preferably, the coercivity difference ratio is 100% or more. The coercivity difference ratio here is defined as (Hc(max)-Hc(min)) / Hc(min)×100(%), where Hc(max) is the maximum coercivity and Hc(min) is the minimum coercivity within the flat surface.

[0085] The coercive force can be easily evaluated using a vibrating sample magnetometer (VSM) or the like. When the coercive force is low, a coercive force of 0.1 Oe or less can be measured by using a low magnetic field unit. The measurement is performed by changing the direction of the measuring magnetic field within the plane of the compacted powder material (within a plane parallel to the flat surfaces of the flat magnetic metal particles).

[0086] When calculating the coercive force, the difference between the magnetic fields at the two points where the horizontal axis intersects (magnetic fields H1 and H2 where magnetization becomes zero) can be divided by 2 (i.e., coercive force = |H2-H1| / 2).

[0087] From the viewpoint of imparting magnetic anisotropy, it is preferable that the magnetic metal particles are arranged with their maximum length direction aligned. Whether the maximum length direction is aligned can be determined by observing the magnetic metal particles contained in the compacted powder material using a TEM, SEM, optical microscope, etc., determining the angle between the maximum length direction and an arbitrarily determined reference line, and then judging the degree of variation. Preferably, the average degree of variation is determined for 20 or more flat magnetic metal particles. However, if it is not possible to observe 20 or more flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and determine the average degree of variation for them. In this specification, the maximum length direction is said to be aligned when the degree of variation is within a range of ±30°. The degree of variation is more preferably within a range of ±20°, and even more preferably within a range of ±10°. This is desirable because it makes it easier to impart magnetic anisotropy to the compacted powder material. It is even more preferable that the first direction of one or both of the multiple recesses and multiple protrusions on the flat surface is aligned in the maximum length direction. This is desirable because it imparts large magnetic anisotropy.

[0088] In the compacted powder material, the "arrangement ratio" of the approximate first direction aligned with the second direction is preferably 30% or more. More preferably, it is 50% or more, and even more preferably, 75% or more. This favorably increases the magnetic anisotropy and improves the magnetic properties as described above. First, for all flat magnetic metal particles to be evaluated in advance, the direction in which the concave or convex portions of each flat magnetic metal particle are aligned most frequently is defined as the first direction, and the direction in which the first direction of each flat magnetic metal particle is aligned most frequently throughout the compacted powder material is defined as the second direction. Next, directions are determined by dividing a 360-degree angle with respect to the second direction at 45-degree intervals. Next, the first direction of each flat magnetic metal particle is classified according to the angle to which it is most closely aligned, and this direction is defined as the "approximate first direction." That is, it is classified into one of four directions: 0 degrees, 45 degrees, 90 degrees, and 135 degrees. The "alignment ratio" is defined as the percentage of particles in which the approximate first direction is aligned in the same direction as the second direction. To evaluate this "alignment ratio," four adjacent flat magnetic metal particles are selected in order and evaluated. This is performed at least three times (more is preferable, for example, five or more times is preferable, and even more preferably ten or more times is preferable), and the average value is used as the alignment ratio. Flat magnetic metal particles in which the orientation of the concave or convex portions cannot be determined are excluded from the evaluation, and the flat magnetic metal particles immediately adjacent to them are evaluated. For example, flat magnetic metal particles obtained by pulverizing ribbons synthesized using a single-roll quenching device often have concave or convex portions on only one flat surface, while the other flat surface does not. When such flat magnetic metal particles are observed using an SEM, there is about a 50% chance that a flat surface without concave or convex portions will be visible on the observation screen (even in this case, the flat surface on the back side should actually have concave or convex portions, but this is excluded in the above evaluation).

[0089] It is also preferable that the most approximate first direction be aligned with the easy axis of magnetization of the compacted powder material. That is, it is preferable that the easy axis of magnetization of the compacted powder material be parallel to the second direction. Because the length direction in which the concave or convex portions are aligned tends to become the easy axis of magnetization due to the effect of shape magnetic anisotropy, aligning this direction as the easy axis of magnetization is preferable because it makes it easier to impart magnetic anisotropy.

[0090] It is preferable that a portion of the intervening phase is attached along the first direction. In other words, it is preferable that a portion of the intervening phase is attached along the direction of the depressions or protrusions on the flat surfaces of the flat magnetic metal particles. This makes it easier to induce magnetic anisotropy in one direction, which is preferable. Furthermore, the attachment of such intervening phase is preferable because it improves the adhesion between the flat magnetic metal particles, thereby improving mechanical properties such as strength and hardness and thermal stability. It is also preferable that the intervening phase contains particulate matter. This maintains an appropriate level of adhesion between the flat magnetic metal particles, reduces distortion (the presence of particulate intervening phase between the flat magnetic metal particles relieves the stress applied to the flat magnetic metal particles), and makes it easier to reduce the coercive force (reducing hysteresis loss and increasing magnetic permeability), which is preferable.

[0091] FIG. 11 is a schematic diagram showing a method for manufacturing a compacted powder material according to a third embodiment. Here, we assume that the compacted powder material is manufactured by uniaxial pressing using a mold. FIGS. 11(a) and 11(b) show a comparative method for manufacturing a compacted powder material. In the comparative example, when performing magnetic field pressing as a preforming step before hot press molding, a mold consisting of a magnetic die and punch is typically used to enhance the effectiveness of magnetic field pressing. In this case, residual magnetization occurs in the mold in the same direction as the applied magnetic field. As a result, a compacted powder material is obtained in which the flat surfaces of the flat magnetic metal particles contained in the compacted powder material are relatively parallel. Therefore, when a magnetic field perpendicular to the molding surface is applied, the demagnetizing field becomes large, which is a problem in that high magnetic permeability cannot be obtained. Therefore, in this embodiment, as shown in FIG. 11(c), magnetic field pressing is performed using a mold combining a magnetic punch and a non-magnetic die. As a result, no residual magnetization occurs in the die after magnetic field pressing. Furthermore, residual magnetization occurring in the punch separated from the molded body generates magnetic field lines in a direction different from the direction of the applied magnetic field during magnetic field pressing. Furthermore, the molding pressure during hot press molding is intentionally set to a low pressure, for example, a surface pressure of approximately 0.1 to 10 MPa. This makes it easier for the flat magnetic metal particles to rotate due to the influence of magnetic field lines passing through the molded body during hot press molding. This allows for a compacted powder material with moderate orientation variation to be obtained. Furthermore, the flat magnetic metal particles are more likely to aggregate along the magnetic field lines passing through the molded body. This results in an arrangement of flat magnetic metal particles with a high degree of proximity. Furthermore, because the molding pressure is low, the stress that curves the flat magnetic metal particles is low, resulting in a small curvature rate of the flat magnetic metal particles. By achieving this characteristic arrangement of flat magnetic metal particles, it becomes possible to produce a compacted powder material with high magnetic permeability without reducing strength. It goes without saying that the compacted powder material of this embodiment can be preferably produced without relying on uniaxial pressing using the above-mentioned mold.

[0092] FIG. 12 is a microscope (SEM) photograph of a predetermined cross section of a compacted powder material in the third embodiment. The upper part of FIG. 12 shows a microscope (SEM) photograph of a cross section of a compacted powder material of a comparative embodiment. It can be seen that the orientation angles of the flat magnetic metal particles shown in light gray are aligned horizontally, with little orientation variation. In the compacted powder material of the comparative embodiment, the orientation variation is small, resulting in low magnetic permeability in the vertical magnetic field in FIG. 12. In contrast, in the compacted powder material of the embodiment shown in the lower part of FIG. 12, the orientation variation of the flat magnetic metal particles is large. Due to the large orientation variation of the flat magnetic metal particles, the magnetic permeability is higher in the vertical magnetic field in FIG. 12 than in the compacted powder material of the comparative embodiment. There is a concern that large orientation variation may result in a decrease in strength. However, since there are many locations where the flat magnetic metal particles are close to each other, the effective thickness of the flat magnetic metal particles increases with respect to external stress. This increases bending rigidity and improves strength. Furthermore, compacting the flat magnetic metal particles with a small curvature reduces the peel stress acting at the interface between the flat magnetic metal particles and the intervening phase, preventing a decrease in strength. Furthermore, because the curvature of the flat magnetic metal particles increases coercivity, a small curvature can also keep the coercivity low. However, if the compacting pressure is set so low that the curvature is almost zero, a high-density compacted powder material cannot be obtained. Therefore, the compacting conditions must be controlled so that the curvature is at least 0.01%. If a high-density compacted powder material cannot be obtained and the porosity becomes high, the strength of the compacted powder material decreases. On the other hand, if there are no voids at all (i.e., the porosity is zero), there will be no voids to pin the growth of cracks that occur when stress is applied to the compacted powder material. Therefore, when stress above a certain level is applied, cracks will grow rapidly and the material will break in a very short time, making it difficult to use in practice. Therefore, the presence of a small amount of voids in the compacted powder material is desirable. Specifically, when the orientation variation of the flat magnetic metal particles in a specified cross section of the compacted powder material is 30 degrees or more and 45 degrees or less, the proximity ratio is 3% or more and 10% or less, and the curvature ratio is 0.01% or more and 0.6% or less, a compacted powder material that combines high magnetic permeability and strength can be obtained.Preferably, the orientation variation is 35 degrees to 45 degrees, the proximity ratio is 3% to 8%, and the curvature ratio is 0.01% to 0.5%. More preferably, the orientation variation is 40 degrees to 45 degrees, the proximity ratio is 3% to 5%, and the curvature ratio is 0.01% to 0.4%. Furthermore, the porosity is preferably 0.01% to 10%, more preferably 0.01% to 8%, and even more preferably 0.01% to 5%. This embodiment makes it possible to manufacture and provide a compacted powder material that has both high magnetic permeability and high strength.

[0093] The orientation variation, proximity rate, and curvature rate of the flat magnetic metal particles in a specified cross section of the pressed powder material can be determined from observation images obtained using, for example, SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) or TEM-EDX (Transmission Electron Microscope-Energy Dispersive X-ray Spectroscopy).

[0094] FIG. 13 is a schematic diagram showing a method for calculating the proximity ratio of flat magnetic metal particles in a predetermined cross section of a compacted powder material according to the third embodiment. As an example, a method for calculating the proximity ratio using SEM-EDX will be described below. First, a conductive coating such as a carbon coating is formed on the surface of the compacted powder material to be observed, and the surface is observed. The magnification is set to a level that can accommodate 50 or more flat magnetic metal particles, and an SEM-EDX image is acquired. Within the SEM-EDX image, regions containing one of the elements iron (Fe), cobalt (Co), and nickel (Ni) as the main component are defined as flat magnetic metal particle phases; regions containing one of the elements oxygen (O), carbon (C), nitrogen (N), and fluorine (F) in greater amounts than the flat magnetic metal particle phase are defined as intervening phases; and regions containing no elements (or containing elements below the detection limit) are defined as voids. In this case, the area of ​​the voids is divided by the total area of ​​the flat magnetic metal phase, the intervening phase, and the voids, and the average value is calculated for at least five fields of view. The interface between the flat magnetic metal particle phase and the intervening phase or the flat magnetic metal particle phase and the voids is extracted for all flat magnetic metal particle phases, and the total length of the extracted interfaces is measured. Furthermore, the points where the interfaces of the flat magnetic metal particle phases are close to each other are extracted, specifically, the points where the interfaces of two adjacent flat magnetic metal particle phases are close to each other at a distance of less than one-fifth the thickness of the flat magnetic metal particle phase with the smaller flat magnetic metal particle thickness calculated using the above-mentioned method, and the total length of the adjacent points for all particles is measured. The length of the interfaces and adjacent points can be measured physically using a measuring device on the SEM image, or if the image is acquired electronically, it can be measured by using a boundary detection algorithm to detect smooth boundaries and calculate the length of the boundary lines. The value obtained by dividing the total length of the adjacent portions by the total length of the interface is defined as the proximity ratio in this SEM-EDX image. For one compacted powder material, the proximity ratio in each SEM-EDX image is calculated for at least five or more fields of view using the same method as above, and the average of these values ​​is used as the proximity ratio of this compacted powder material.The proximity ratio is X / Y, where X is the sum of the lengths of the peripheries of two flat magnetic metal particles among the plurality of flat magnetic metal particles, where the distance between the two flat magnetic metal particles is less than one-fifth of the thickness of the smaller of the two flat magnetic metal particles, and Y is the sum of the peripheries of the plurality of flat magnetic metal particles.

[0095] FIG. 14 is a schematic diagram showing a method for calculating the curvature of flat magnetic metal particles in a predetermined cross section of a compacted powder material according to the third embodiment. As an example, a method for calculating the curvature using SEM-EDX is described below. First, a conductive coating, such as a carbon coating, is formed on the surface of the compacted powder material to be observed, and the surface is observed. The magnification is set to a value large enough to fit 50 or more flat magnetic metal particles, and an SEM-EDX image is acquired. Within the SEM-EDX image, regions containing iron (Fe), cobalt (Co), and nickel (Ni) as the primary component are defined as flat magnetic metal particle phases; regions containing more of oxygen (O), carbon (C), nitrogen (N), and fluorine (F) than the flat magnetic metal particle phase are defined as intervening phases; and regions containing no elements (or containing elements below the detection limit) are defined as voids. For all flat magnetic metal particle phases, a curve passing through the middle of the flat surfaces on both sides of the flat magnetic metal particles, i.e., the center of the flat magnetic metal particles, is extracted. The length of the extracted curve and the linear distance between the endpoints of the curve are measured, and the value obtained by dividing the length of the curve by the linear distance minus 1 is defined as the curvature of the flat magnetic metal particle. For one compacted powder material, the curvature of all flat magnetic metal particles shown in all SEM-EDX images acquired in at least five fields of view is calculated, and the average of these values ​​is used as the curvature of the compacted powder material. The curvature of a flat magnetic metal particle is (L1 / L2)-1, where L1 is the length of the curve passing through the center of the flat magnetic metal particle in a given cross-section of the compacted powder material, and L2 is the distance between the endpoints of the curve.

[0096] Furthermore, the average orientation angle between the flat surfaces and the flat surfaces of the compacted powder material can be calculated using the following method using an SEM, for example, in the case of a compacted powder material consisting of flat magnetic metal particles with an average thickness of 10 to 20 μm and an average ratio of the average length within the flat surfaces to the thickness of approximately 5 to 20. First, an SEM-EDX image with an observation area of ​​500 μm x 500 μm is obtained. Note that the observation area may be changed appropriately within reasonable limits depending on the size of the flat magnetic metal particles (average thickness, average ratio of the average length within the flat surfaces to the thickness), but it is preferable to select an area that contains at least 20 flat magnetic metal particles within the observation area. Within the obtained SEM-EDX image, regions containing one of the elements iron (Fe), cobalt (Co), and nickel (Ni) as the main component are identified as flat magnetic metal particles. Consider the rectangle with the smallest area circumscribing the flat magnetic metal particle, and define the angle between the long side of that rectangle and the plane of the compacted powder material as the orientation angle of that flat magnetic metal particle. The orientation angles of all flat magnetic metal particles within the same observation field are calculated, and the average of the remaining values ​​excluding the maximum and minimum values ​​is defined as the orientation angle of the observation surface. However, some flat magnetic metal particles may be very difficult to distinguish, and in such cases, they may be excluded from the observation target within the bounds of common sense. Using a similar calculation method, the orientation angles of all other planes of the compacted powder material are calculated, and the orientation angle of the plane with the smallest orientation angle is defined as the orientation angle of that compacted powder material.

[0097] Furthermore, it is preferable that the lattice mismatch ratio between the interstitial phase and the flat magnetic metal particles be 0.1% or more and 50% or less. This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. Setting the lattice mismatch within the above range can be achieved by selecting the combination of the interstitial phase composition and the flat magnetic metal particles 10 composition. For example, Ni with an fcc structure has a lattice constant of 3.52 Å, and MgO with an NaCl structure has a lattice constant of 4.21 Å, resulting in a lattice mismatch between the two of (4.21-3.52) / 3.52×100=20%. In other words, by setting the main composition of the flat magnetic metal particles to Ni with an fcc structure and the main composition of the interstitial phase 20 to MgO, the lattice mismatch can be set to 20%. In this way, by selecting the combination of the main composition of the flat magnetic metal particles and the main composition of the interstitial phase, it is possible to set the lattice mismatch within the above range.

[0098] The intervening phase contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). This is because it can increase the resistance. The electrical resistivity of the intervening phase is preferably higher than that of the flat magnetic metal particles. This is because it can reduce the eddy current loss of the flat magnetic metal particles. The intervening phase surrounds the flat magnetic metal particles, which is preferable because it can improve the oxidation resistance and thermal stability of the flat magnetic metal particles. Among these, those containing oxygen are more preferable from the viewpoint of high oxidation resistance and high thermal stability. The intervening phase also plays a role in mechanically bonding the flat magnetic metal particles together, which is also preferable from the viewpoint of high strength.

[0099] The intervening phase may also be an "oxide having a eutectic system," "containing a resin," or "containing at least one magnetic metal selected from Fe, Co, and Ni." These points will be explained below.

[0100] First, we will explain the first case, "when the intervening phase is an oxide having a eutectic system." In this case, the intervening phase includes an oxide having a eutectic system containing at least two third elements selected from the group consisting of B (boron), Si (silicon), Cr (chromium), Mo (molybdenum), Nb (niobium), Li (lithium), Ba (barium), Zn (zinc), La (lanthanum), P (phosphorus), Al (aluminum), Ge (germanium), W (tungsten), Na (sodium), Ti (titanium), As (arsenic), V (vanadium), Ca (calcium), Bi (bismuth), Pb (lead), Te (tellurium), and Sn (tin). In particular, it is preferable to include a eutectic system containing at least two elements selected from B, Bi, Si, Zn, and Pb. This strengthens the adhesion between the flat magnetic metal particles and the intervening phase (increasing bonding strength), and mechanical properties such as thermal stability, strength, and toughness are likely to be improved.

[0101] Furthermore, the softening point of the above-mentioned eutectic oxide is preferably 200°C or higher and 600°C or lower, more preferably 400°C or higher and 500°C or lower. More preferably, the eutectic oxide contains at least two elements selected from B, Bi, Si, Zn, and Pb, and has a softening point of 400°C or higher and 500°C or lower. This strengthens the bond between the flat magnetic metal particles and the above-mentioned eutectic oxide, which facilitates improvements in mechanical properties such as thermal stability, strength, and toughness. When integrating the flat magnetic metal particles with the above-mentioned eutectic oxide, the flat magnetic metal particles are integrated by heat treatment at a temperature near the softening point of the above-mentioned eutectic oxide, preferably at a temperature slightly higher than the softening point, thereby improving the adhesion between the flat magnetic metal particles and the above-mentioned eutectic oxide and improving the mechanical properties. Generally, the higher the heat treatment temperature, the better the adhesion between the flat magnetic metal particles and the above-mentioned eutectic oxide, and the better the mechanical properties. However, if the heat treatment temperature is too high, the thermal expansion coefficient increases, which can actually reduce the adhesion between the flat magnetic metal particles and the oxide having the eutectic system (if the difference between the thermal expansion coefficient of the flat magnetic metal particles and the oxide having the eutectic system increases, the adhesion can be further reduced). Furthermore, if the crystallinity of the flat magnetic metal particles is amorphous or amorphous-like, a high heat treatment temperature is undesirable because it promotes crystallization and increases the coercivity. Therefore, to achieve both mechanical properties and coercivity, it is preferable to set the softening point of the oxide having the eutectic system to 200°C or higher and 600°C or lower, more preferably 400°C or higher and 500°C or lower, and integrate the particles by heat treatment at a temperature near the softening point of the oxide having the eutectic system, preferably slightly higher than the softening point. Furthermore, it is preferable to use the integrated material at a temperature lower than the softening point when actually using it in a device or system.

[0102] The oxide having the eutectic system preferably has a glass transition point. Furthermore, the oxide having the eutectic system preferably has a thermal expansion coefficient of 0.5×10 -6 / ℃ or more 40×10 -6 / ° C. or less. This strengthens the bond between the flat magnetic metal particles 10 and the oxide having the eutectic system, and improves the thermal stability and mechanical properties such as strength and toughness.

[0103] It is more preferable to include at least one particulate (preferably spherical) eutectic particle with a particle size of 10 nm to 10 μm. The eutectic particle contains the same material as the oxide having the eutectic system, except that it is particulate. Voids may be present in the compacted powder material, and it is easy to observe that some of the oxide having the eutectic system is particulate, preferably spherical. Even when there are no voids, the particulate or spherical interface can be easily identified. The particle size of the eutectic particle is more preferably 10 nm to 1 μm, and even more preferably 10 nm to 100 nm. This allows the flat magnetic metal particles to maintain adhesion between them during heat treatment while also appropriately relaxing stress, thereby reducing the strain applied to the flat magnetic metal particles and reducing coercive force. This also reduces hysteresis loss and improves magnetic permeability. The particle size of the eutectic particle can be measured by TEM or SEM observation.

[0104] Furthermore, the intervening phase preferably has a softening point higher than that of the oxide having the eutectic system, more preferably higher than 600°C, and further contains intermediate particles containing at least one element selected from the group consisting of O (oxygen), C (carbon), N (nitrogen), and F (fluorine). The presence of the intermediate particles between the flat magnetic metal particles can prevent the flat magnetic metal particles from thermally fusing together and deteriorating in properties when the compacted powder material is exposed to high temperatures. In other words, the presence of the intermediate particles is desirable mainly for thermal stability. Furthermore, the softening point of the intermediate particles is higher than that of the oxide having the eutectic system, more preferably a softening point of 600°C or higher, thereby further improving thermal stability.

[0105] The intermediate particles preferably contain at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements, and at least one element selected from the group consisting of O (oxygen), C (carbon), N (nitrogen), and F (fluorine). More preferably, the intermediate particles are oxides or composite oxides containing oxygen, from the viewpoint of high oxidation resistance and high thermal stability. Oxides such as aluminum oxide (Al2O3), silicon dioxide (SiO2), titanium oxide (TiO2), and zirconium oxide (ZrO3), as well as composite oxides such as Al-Si-O, are particularly preferred from the viewpoint of high oxidation resistance and high thermal stability.

[0106] Examples of methods for producing a compacted powder material containing intermediate particles include mixing flat magnetic metal particles and intermediate particles (aluminum oxide (Al2O3) particles, silicon dioxide (SiO2) particles, titanium oxide (TiO2) particles, zirconium oxide (ZrO3) particles, etc.) using a ball mill or the like to create a dispersed state, and then integrating them by press molding or the like. There are no particular restrictions on the dispersion method as long as it can achieve an appropriate dispersion.

[0107] Next, we will explain the second case, "when the intervening phase contains a resin." In this case, the resin is not particularly limited, but examples include polyester resins, unsaturated polyester resins, polyethylene resins, polystyrene resins, polyvinyl chloride resins, polyvinyl butyral resins, polyvinyl alcohol resins, polybutadiene resins, Teflon (registered trademark, polytetrafluoroethylene) resins, polyurethane resins, cellulose resins, ABS resins, nitrile-butadiene rubbers, styrene-butadiene rubbers, silicone resins, other synthetic rubbers, natural rubbers, epoxy resins, phenolic resins, allyl resins, polybenzimidazole resins, amide resins, polyimide resins, polyamideimide resins, bismaleimide resins, and copolymers of these resins with any copolymerization material. In particular, to achieve high thermal stability, it is preferable to include a highly heat-resistant silicone resin, polyimide resin, or bismaleimide resin. This strengthens the bond between the flat magnetic metal particles and the intervening phase, which tends to improve thermal stability and mechanical properties such as strength and toughness.

[0108] The resin (intervening phase) preferably exhibits a weight loss of 5% or less after heating in an air atmosphere at 180°C for 3,000 hours, more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.1% or less. Furthermore, the weight loss after heating in an air atmosphere at 220°C for 200 hours is preferably 5% or less, even more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.1% or less. Furthermore, the weight loss after heating in an air atmosphere at 250°C for 200 hours is preferably 5% or less, even more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.1% or less. These weight loss evaluations are performed using virgin material. A virgin material refers to a material that has been molded into a usable state and has not been exposed to heat (e.g., heat above 40°C), chemicals, sunlight (ultraviolet rays), or the like since that state. The weight loss rate is calculated from the masses before and after heating using the following formula: Weight loss rate (%) = [mass before heating (g) - mass after heating (g)] / mass before heating (g) × 100. Preferably, the strength after heating in an air atmosphere at 180°C for 20,000 hours is at least half of the strength before heating. More preferably, the strength after heating in an air atmosphere at 220°C for 20,000 hours is at least half of the strength before heating. Preferably, the strength satisfies the H-type requirements specified by the Japanese Industrial Standards (JIS). In particular, it is preferable that the strength satisfies the heat resistance requirement to withstand a maximum temperature of 180°C. More preferably, it is preferable that the strength satisfies the H-type requirements specified by the Japanese Railway Standards (JRE). In particular, it is preferable that the strength satisfies the heat resistance requirement to withstand a temperature rise of 180°C above the ambient temperature (standard: 25°C, maximum: 40°C). Resins suitable for this purpose include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, aromatic polyimide, aromatic polyamide, aromatic polyamideimide, polybenzoxazole, fluororesin, silicone resin, and liquid crystal polymer. These resins are preferred because they have high heat resistance due to their strong intermolecular cohesive force. Among these, aromatic polyimide and polybenzoxazole are preferred because they have a high proportion of rigid units in the molecule and therefore have higher heat resistance. Thermoplastic resins are also preferred.The above-mentioned specifications for the rate of weight loss upon heating, the strength, and the type of resin are each effective in improving the heat resistance of the resin. Furthermore, when a compacted powder material consisting of a plurality of flat magnetic metal particles and an intervening phase (here, resin) is formed, these specifications increase the heat resistance of the compacted powder material (increasing thermal stability), which favorably improves mechanical properties such as strength and toughness after exposure to high temperatures (e.g., the above-mentioned 200°C or 250°C) or at high temperatures (e.g., the above-mentioned 200°C or 250°C). Furthermore, since many intervening phases remain surrounding the flat magnetic metal particles even after heating, the material has excellent oxidation resistance and is less susceptible to deterioration of magnetic properties due to oxidation of the flat magnetic metal particles, which is favorable.

[0109] Furthermore, the weight loss rate of the compacted powder material after heating at 180°C for 3,000 hours is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.1% or less. Furthermore, the weight loss rate of the compacted powder material after heating at 220°C for 3,000 hours is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.1% or less. Furthermore, the weight loss rate of the compacted powder material after heating at 250°C in an air atmosphere for 200 hours is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.1% or less. The weight loss rate is evaluated in the same manner as for the resin described above. Furthermore, it is preferable that the strength of the compacted powder material after heating at 180°C in an air atmosphere for 20,000 hours is at least half of its strength before heating. It is even more preferable that the strength of the compacted powder material after heating at 220°C in an air atmosphere for 20,000 hours is at least half of its strength before heating. Furthermore, it is preferable that the material satisfies the H-type requirements specified by the Japanese Industrial Standards (JIS). In particular, it is preferable that the material satisfies the heat resistance requirement for a maximum temperature of 180°C. Even more preferably, it is preferable that the material satisfies the H-type requirements specified by the Japanese National Railways Standards (JRE). In particular, it is preferable that the material satisfies the heat resistance requirement for a temperature rise of 180°C relative to the ambient temperature (standard: 25°C, maximum: 40°C). The above-mentioned specifications for the thermal weight loss rate, strength, and resin type are each effective in improving the heat resistance of the compacted powder material, resulting in a highly reliable material. Furthermore, the compacted powder material exhibits improved heat resistance (improved thermal stability), which is favorable for improving mechanical properties such as strength and toughness after exposure to high temperatures (e.g., the above-mentioned 200°C or 250°C). Furthermore, since many interstitial phases remain surrounding the flat magnetic metal particles even after heating, the material exhibits excellent oxidation resistance and is less susceptible to deterioration of magnetic properties due to oxidation of the flat magnetic metal particles, which is favorable.

[0110] Furthermore, it is preferable that the resin contains a crystalline resin that does not have a glass transition temperature up to the thermal decomposition temperature. It is also preferable that the resin contains a resin with a glass transition temperature of 180°C or higher, and more preferably a resin with a glass transition temperature of 220°C or higher. It is even more preferable that the resin contains a resin with a glass transition temperature of 250°C or higher. Generally, the higher the heat treatment temperature of flat magnetic metal particles, the larger the crystal grain size. Therefore, if it is necessary to reduce the crystal grain size of the flat magnetic metal particles, it is preferable that the glass transition temperature of the resin used is not too high, specifically, 600°C or lower. Furthermore, it is preferable that the crystalline resin that does not have a glass transition temperature up to the thermal decomposition temperature contains a resin with a glass transition temperature of 180°C or higher, and even more preferably a resin with a glass transition temperature of 220°C or higher. Specifically, it is preferable that the resin contains a polyimide with a glass transition temperature of 180°C or higher, more preferably a polyimide with a glass transition temperature of 220°C or higher, and even more preferably a thermoplastic polyimide. This facilitates fusion to the magnetic metal particles, making it particularly suitable for use in powder compaction. Preferred thermoplastic polyimides include those having imide bonds in the polymer chain, such as thermoplastic aromatic polyimides, thermoplastic aromatic polyamideimides, thermoplastic aromatic polyetherimides, thermoplastic aromatic polyesterimides, and thermoplastic aromatic polyimidesiloxanes. Among these, those having a glass transition temperature of 250°C or higher are preferred because they have higher heat resistance.

[0111] Aromatic polyimides and polybenzoxazoles have a planar structure formed by direct bonding of aromatic rings and heterocyclic rings, which are fixed by π-π stacking, resulting in high heat resistance. This allows for a high glass transition temperature and improved thermal stability. Furthermore, the desired glass transition temperature can be easily adjusted by appropriately incorporating bending units such as ether bonds into the molecular structure. Among these, from the standpoint of strength, it is preferable for the benzene ring structure of the acid anhydride-derived unit constituting the imide polymer to be one of biphenyl, triphenyl, and tetraphenyl structures. This maintains the symmetrical structure between imide groups, which affects heat resistance, and also improves material strength by providing long-range orientation. A preferred aromatic polyimide structure for this purpose is represented by the following chemical formula (1). In other words, the polyimide resin of this embodiment contains a repeating unit represented by the following chemical formula (1). [ka] (1) In chemical formula (1), R represents a biphenyl, triphenyl, or tetraphenyl structure, and R' represents a structure having at least one aromatic ring within the structure.

[0112] When determining the properties (weight loss rate, resin type, glass transition temperature, molecular structure, etc.) of the intervening phase (resin in this case) that is a constituent of the compacted powder material, only the resin portion is cut out from the compacted powder material and various property evaluations are performed. If it is not possible to determine whether it is resin by visual inspection, elemental analysis using EDX or the like is used to distinguish between resin and magnetic metal particles.

[0113] The higher the resin content in the entire compacted powder material, the more smoothly the polymer can connect the polymer wetting (covering) the flat magnetic metal particles with the polymer wetting (covering) adjacent flat magnetic metal particles, improving mechanical properties such as strength. This is also desirable because it increases electrical resistivity and reduces eddy current loss in the compacted powder material. On the other hand, the higher the resin content, the lower the proportion of flat magnetic metal particles, which reduces the saturation magnetization and magnetic permeability of the compacted powder material, making this undesirable. To achieve a well-balanced material that comprehensively considers mechanical properties such as strength, electrical resistivity, eddy current loss, saturation magnetization, and magnetic permeability, the resin content in the entire compacted powder material should be 93 wt% or less, more preferably 86 wt% or less, even more preferably 2 wt% to 67 wt%, and even more preferably 2 wt% to 43 wt%. Furthermore, the content of flat magnetic metal particles is preferably 7 wt% or more, more preferably 14 wt% or more, even more preferably 33 wt% to 98 wt%, and even more preferably 57 wt% to 98 wt%. Furthermore, as the particle diameter of the flat magnetic metal particles becomes smaller, the surface area increases and the amount of resin required increases dramatically, so it is preferable for the flat magnetic metal particles to have a moderately large particle diameter. This allows the compacted powder material to have a high saturation magnetization and high magnetic permeability, which is advantageous for miniaturizing and increasing the output of the system.

[0114] Next, we will explain the third case, "where the intervening phase contains at least one magnetic metal selected from Fe, Co, and Ni and is magnetic." In this case, the magnetic properties of the intervening phase are preferable because the flat magnetic metal particles are more likely to be magnetically bonded to each other, improving the magnetic permeability. Furthermore, the magnetic domain structure is stabilized, which also improves the frequency characteristics of the magnetic permeability, making this preferable. Note that the term "magnetic" here refers to ferromagnetism, ferrimagnetism, weak magnetism, antiferromagnetism, etc. In particular, ferromagnetism and ferrimagnetism are preferable because they enhance the magnetic bonding force. The magnetic properties of the intervening phase can be evaluated using a VSM (Vibrating Sample Magetometer) or the like. The magnetic properties of the intervening phase, containing at least one magnetic metal selected from Fe, Co, and Ni, can be easily examined using EDX or the like.

[0115] The three forms of the intervening phase have been described above. It is preferable that at least one of these three conditions be satisfied, but two or more, or even all three, may be satisfied. The "intervening phase being an oxide having a eutectic system" (first case) is slightly inferior in mechanical properties such as strength compared to the "intervening phase being a resin" (second case). However, it is excellent in terms of ease of strain release, particularly in terms of facilitating the development of low coercivity, and is therefore preferable (this facilitates the realization of low hysteresis loss and high magnetic permeability, making it preferable). Furthermore, it is often more heat-resistant than resin, and is therefore preferable because it also has excellent thermal stability. Conversely, the "intervening phase containing a resin" (second case) has the disadvantage that the high adhesion between the flat magnetic metal particles and the resin makes it easy for stress to be applied (easy strain to be introduced), which tends to increase the coercivity. However, it is preferable because it is excellent in terms of mechanical properties such as strength. "When the intervening phase contains at least one magnetic metal selected from Fe, Co, and Ni and has magnetism" (the third case), the flat magnetic metal particles are easily magnetically bonded to each other, which is particularly preferable because it is extremely excellent in terms of high magnetic permeability and low coercive force (hence low hysteresis loss). Taking into account the above advantages and disadvantages, it is possible to use them appropriately or combine several to create a well-balanced product.

[0116] It is desirable that the flat magnetic metal particles contained in the powder material satisfy the requirements described in the first and second embodiments. Since the contents are redundant, a description thereof will be omitted here.

[0117] The pressed powder material may have a laminated structure consisting of a magnetic layer containing the flat magnetic metal particles and an intermediate layer containing any of O, C, and N. In the magnetic layer, the flat magnetic metal particles are preferably oriented (oriented so that their flat surfaces are parallel to each other). It is also preferable to set the magnetic permeability of the intermediate layer lower than that of the magnetic layer. These measures are preferable because they realize a pseudo-thin film laminated structure and increase the magnetic permeability in the layer direction. This structure is also preferable because it can increase the ferromagnetic resonance frequency and reduce ferromagnetic resonance loss. Furthermore, this laminated structure is also preferable because it stabilizes the magnetic domain structure and achieves low magnetic loss. To further enhance these effects, it is more preferable to set the magnetic permeability of the intermediate layer lower than that of the intervening phase (intervening phase in the magnetic layer). This is preferable because it can further increase the magnetic permeability in the layer direction in the pseudo-thin film laminated structure. It is also preferable because it can further increase the ferromagnetic resonance frequency and reduce ferromagnetic resonance loss.

[0118] As described above, according to this embodiment, it is possible to provide a powder material having excellent magnetic properties such as low magnetic loss.

[0119] (Fourth embodiment) The system and device of this embodiment include the compacted powder material of the third embodiment. Therefore, descriptions of the contents overlapping with the first to third embodiments will be omitted. The compacted powder material components included in this system and device include, for example, rotating electric machines (e.g., motors, generators, etc.) such as various motors and generators, cores of transformers, inductors, choke coils, filters, and magnetic wedges for rotating electric machines. FIG. 15 is a conceptual diagram of a motor system of the fourth embodiment. The motor system is an example of a rotating electric machine system. The motor system is a system including a control system for controlling the rotation speed and power (output power) of a motor. Methods for controlling the rotation speed of a motor include control methods using a bridge servo circuit, proportional current control, voltage comparison control, frequency synchronization control, and PLL (Phase Locked Loop) control. As an example, a PLL control method is shown in FIG. 15. A motor system that controls the rotation speed of a motor using a PLL includes a motor, a rotary encoder that converts the mechanical displacement of the motor's rotation into an electrical signal to detect the motor's rotation speed, a phase comparator that compares the motor's rotation speed given by a command with the motor's rotation speed detected by the rotary encoder and outputs the difference between the rotation speeds, and a controller that controls the motor to reduce the difference in rotation speed. Meanwhile, methods for controlling motor power include PWM (Pulse Width Modulation) control, PAM (Pulse Amplitude Modulation) control, vector control, pulse control, bipolar drive, pedestal control, and resistance control. Other control methods include microstep drive control, multiphase drive control, inverter control, and switching control. An example of an inverter-based control method is shown in Figure 15. A motor system that controls motor power using an inverter includes an AC power supply, a rectifier that converts the AC power supply output into DC current, an inverter circuit that converts the DC current into AC at a desired frequency, and a motor controlled by the AC current.

[0120] Fig. 16 shows a conceptual diagram of a motor according to a fourth embodiment. The motor 200 is an example of a rotating electric machine. A first stator and a second rotor are arranged in the motor 200. While the figure shows an inner rotor type in which the rotor is arranged inside the stator, an outer rotor type in which the rotor is arranged outside the stator may also be used.

[0121] FIG. 17 is a conceptual diagram of a motor core (stator) according to the fourth embodiment. FIG. 18 is a conceptual diagram of a motor core (rotor) according to the fourth embodiment. The motor core 300 (motor core) corresponds to the core of the stator and the rotor. This point will be explained below. FIG. 17 is an example of a cross-sectional conceptual diagram of a first stator. The first stator has a core and a winding. The winding is wound around a part of a protrusion on the inside of the core that the core has. The compacted powder material of the third embodiment can be placed inside this core. FIG. 18 is an example of a cross-sectional conceptual diagram of a first rotor. The first rotor has a core and a winding. The winding is wound around a part of a protrusion on the outside of the core that the core has. The compacted powder material of the third embodiment can be placed inside this core.

[0122] 17 and 18 show only one example of a motor, and the application of the compacted powder material is not limited to this. It can be used in all kinds of motors as a core that makes it easier to guide magnetic flux.

[0123] FIG. 19 is a conceptual diagram of a transformer according to the fourth embodiment. FIG. 20 is a conceptual diagram of an inductor (ring-shaped inductor, rod-shaped inductor) according to the fourth embodiment. FIG. 21 is a conceptual diagram of an inductor (chip inductor, planar inductor) according to the fourth embodiment. These are also shown merely as examples. As with motor cores, powder materials can be applied to all types of transformers and inductors in order to facilitate the conduction of magnetic flux or to utilize high magnetic permeability in the transformer 400 and inductor 500.

[0124] FIG. 22 is a conceptual diagram of a generator 600 according to the fourth embodiment. The generator 600 is an example of a rotating electrical machine. The generator 600 includes a second stator 630 using the compacted powder material according to any one of the first to third embodiments as a core, and / or a second rotor 640 using the compacted powder material according to any one of the first to third embodiments as a core. In the figure, the second rotor 640 is disposed inside the second stator 630, but it may be disposed outside. The second rotor 640 is connected to a turbine 610 provided at one end of the generator 600 via a shaft 620. The turbine 610 is rotated, for example, by a fluid supplied from an external source (not shown). Note that instead of a turbine rotated by a fluid, the shaft can also be rotated by transmitting dynamic rotation, such as regenerative energy from an automobile. Various known configurations can be employed for the second stator 630 and the second rotor 640.

[0125] The shaft is in contact with a commutator (not shown) that is arranged on the opposite side of the second rotor 640 from the turbine. The electromotive force generated by the rotation of the second rotor 640 is boosted to a system voltage and transmitted as power for the generator via a phase isolation bus (not shown) and a main transformer (not shown). Note that the second rotor 640 is charged with static electricity from the turbine and axial current due to power generation. For this reason, the generator is provided with brushes 650 for discharging the charge on the second rotor 640.

[0126] The rotating electric machine of this embodiment can be preferably used in railway vehicles, for example, as a motor 200 that drives a railway vehicle, or as a generator 500 that generates electricity for driving a railway vehicle.

[0127] Figure 23 is a conceptual diagram showing the relationship between the direction of magnetic flux and the arrangement direction of the compacted powder material. Figure 23 considers a case where the flat surfaces of the flat magnetic metal particles are arranged parallel to the XY plane. First, in both the domain wall motion type and the rotational magnetization type, it is preferable to arrange the flat surfaces of the flat magnetic metal particles contained in the compacted powder material as parallel to each other as possible and in a layered manner relative to the direction of magnetic flux. This is because eddy current loss can be reduced by minimizing the cross-sectional area of ​​the flat magnetic metal particles that penetrate the magnetic flux. Furthermore, in the domain wall motion type, it is preferable to arrange the easy axis of magnetization (direction of the arrow) within the flat surfaces of the flat magnetic metal particles parallel to the direction of magnetic flux. This allows the material to be used in a direction that further reduces coercive force, which is preferable because it reduces hysteresis loss. It is also preferable because it increases magnetic permeability. Conversely, in the rotational magnetization type, it is preferable to arrange the easy axis of magnetization (direction of the arrow) within the flat surfaces of the flat magnetic metal particles perpendicular to the direction of magnetic flux. This allows the material to be used in a direction that further reduces the coercive force, which is preferable because it reduces hysteresis loss. In other words, it is preferable to understand the magnetization characteristics of the compacted powder material, determine whether it is a domain wall motion type or a rotational magnetization type (the method for determining this is described above), and then arrange it as shown in Figure 17. If the magnetic flux direction is complex, it may be difficult to arrange it exactly as shown in Figure 17, but it is preferable to arrange it as shown in Figure 17 as much as possible. It is desirable to apply the above arrangement method to all systems and devices of this embodiment (for example, cores of rotating electrical machines such as various motors and generators (e.g., motors, generators, etc.), transformers, inductors, choke coils, filters, etc., and magnetic wedges for rotating electrical machines, etc.).

[0128] To be applied to the system and device, the green compact material can be subjected to various processes. For example, in the case of a sintered body, mechanical processing such as polishing or cutting is performed, and in the case of a powder, it can be mixed with a resin such as epoxy resin or polybutadiene. Further, surface treatment can be performed as needed. Furthermore, winding processing can be performed as needed.

[0129] According to the system and device of the present embodiment, it is possible to realize a motor system, a motor, a transformer, a transformer, an inductor, and a generator having excellent characteristics (high efficiency, low loss).

[0130] (Example) Examples 1 to 20 are described in more detail below in comparison with Comparative Examples 1 to 6. Table 1 shows the orientation variation, proximity ratio, and curvature ratio of the flat magnetic metal particles in a predetermined cross section of the compacted powder material obtained by the following Examples and Comparative Examples, as well as the average thickness t of the flat magnetic metal particles and the average value A of the ratio of the average length within the flat surface to the thickness.

[0131] Example 1 First, a ribbon of Fe-Co-B-Si (Fe:Co:B:Si = 552:23:19:6 (at%), Fe:Co = 70:30 (at%), the total amount of added elements B + Si is 25 at% relative to the total amount of Fe + Co + B + Si) is produced using a single-roll quenching device. The obtained ribbon is then heat-treated at 300 °C in an H2 atmosphere. Next, this ribbon is pulverized using a mixer and heat-treated in a magnetic field at 400 °C in an H2 atmosphere to obtain flat magnetic metal particles. The average thickness t of the obtained flat magnetic metal particles is 10 μm, and the average value A of the ratio of the average length within the flat plane to the thickness is 20. The obtained flat magnetic metal particles are mixed with an intervening phase (polyester resin), press-molded in a magnetic field (to orient the flat particles), and then hot-press molded. The hot-press molding conditions are 120 °C, 5 MPa, and 2 hours.

[0132] Examples 2 to 15 By controlling the material of the mold used for hot press molding, the pressing conditions in the magnetic field, and the hot press molding conditions, the orientation variation, proximity rate, and curvature rate of the flat magnetic metal particles in a specified cross section of the obtained compacted powder material are the same as Example 1, except that they are the values ​​shown in Examples 2 to 15 in Table 1.

[0133] (Examples 16 to 20) The average thickness t of the flat magnetic metal particles and the ratio A of the average length within the flat surface to the thickness, and the orientation variation, proximity rate, and curvature rate of the flat magnetic metal particles in a specified cross section of the obtained pressed powder material are the same as Examples 1 and 2 to 15, except that they are the values ​​shown in Examples 6 to 20 in Table 1.

[0134] (Comparative Examples 1 to 6) By controlling the material of the mold used for hot press molding, the pressing conditions in the magnetic field, and the hot press molding conditions, the orientation variation, proximity rate, and curvature rate of the flat magnetic metal particles in a specified cross section of the obtained compacted powder material are the same as in Example 1, except that they are the values ​​shown in Comparative Examples 1 to 6 in Table 1.

[0135] Next, the magnetic permeability ratio and strength ratio were evaluated by the following methods for the evaluation materials of Examples 1 to 20 and Comparative Examples 1 to 6. Table 2 shows the evaluation results.

[0136] (1) Strength ratio: The bending strength of the evaluation sample was measured according to the measurement method of JIS-K7171, and was expressed as the ratio to the bending strength of the sample of Comparative Example 1 (= bending strength of evaluation sample / bending strength of Comparative Example 1). Note that if the evaluation sample is small and does not satisfy the test piece shape specified in JIS K7171, the bending strength of the evaluation sample is estimated using a calibration curve prepared using test pieces of the same size with known bending strengths, and this is used as the bending strength value of the sample.

[0137] (2) Permeability ratio: Using an impedance analyzer, the real and imaginary parts of the permeability of the ring-shaped sample at a frequency of 100 Hz were measured, and the value of the real part was taken as the permeability of the sample, and the ratio to the permeability of the sample of Comparative Example 1 (=permeability of evaluation sample / permeability of Comparative Example 1) was expressed.

[0138] [Table 1]

[0139] [Table 2] As is clear from Table 1, the compacted powder materials of Examples 1 to 20 have an orientation variation of the flat magnetic metal particles in a predetermined cross section of the compacted powder material of 30 degrees or more and 45 degrees or less, a proximity ratio of 3% or more and 10% or less, and a curvature ratio of 0.01% or more and 0.6% or less. On the other hand, in Comparative Examples 1 to 6, any of the orientation variation, proximity ratio, and curvature ratio does not fall within the above ranges.

[0140] As is clear from Table 2, the compacted powder materials of Examples 1 to 20 are superior in magnetic permeability ratio and strength ratio compared to the compacted powder material of Comparative Example 1. This is because the compacted powder material of Comparative Example 1 has low magnetic permeability due to small orientation variation and low strength due to insufficient proximity. In Comparative Examples 2, 3, and 6, the intensity ratio is superior to Comparative Example 1, but the orientation variation is too small in Comparative Examples 2 and 6, and the curvature is too high in Comparative Example 3, resulting in an inferior magnetic permeability ratio. In Comparative Example 5, the magnetic permeability ratio is superior to Comparative Example 1 due to large orientation variation, but the intensity ratio decreases significantly due to the orientation variation, and a decrease in the intensity ratio is unavoidable even when the proximity ratio and curvature are controlled within appropriate ranges. In Comparative Example 4, under manufacturing conditions that make it impossible to densify the compacted powder material, such as when the curvature is too low, both the magnetic permeability ratio and the strength ratio decrease compared to Comparative Example 1. As described above, significant effects can be obtained and high permeability ratios and strength ratios can be achieved simultaneously only when the orientation variation is within the ranges of 30 degrees or more and 45 degrees or less, the proximity ratio is within the ranges of 3% or more and 10% or less, and the curvature ratio is within the ranges of 0.01% or more and 0.6% or less.

[0141] Although several embodiments and examples of the present invention have been described, these embodiments and examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0142] The above-described embodiments can be summarized as the following technical proposals.

[0143] Technical proposal 1 A plurality of flat magnetic metal particles having flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, with an average thickness of 10 nm or more and 100 μm or less, and an average ratio of the average length within the flat surfaces to the thickness of 5 or more and 10,000 or less; and an intervening phase present between the flat magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F), In the pressed powder material, in a predetermined cross section perpendicular to the plane of the pressed powder material, the orientation variation of the multiple flat magnetic metal particles is 30 degrees or more and 45 degrees or less, the proximity rate of the multiple flat magnetic metal particles is 3% or more and 10% or less, and the curvature rate of the multiple flat magnetic metal particles is 0.01% or more and 0.6% or less. Technical proposal 2 The compacted powder material according to Technical Scheme 1, wherein the porosity of the compacted powder material is 0.01% or more and 10% or less. Technical proposal 3 A compacted powder material according to Technical Scheme 1 or Technical Scheme 2, having a difference in coercivity depending on the direction within a plane of the compacted powder material. Technical proposal 4 A compressed powder material described in any one of Technical Schemes 1 to 3, in which at least a portion of the surface of the flat magnetic metal particles is covered with a coating layer having a thickness of 0.1 nm or more and 1 μm or less and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F). Technical proposal 5 A compacted powder material according to any one of Technical Schemes 1 to 4, wherein the intervening phase contains a resin whose weight loss rate after heating at 180°C for 3000 hours is 5% or less. Technical proposal 6 The pressed powder material according to any one of Technical Schemes 1 to 5, wherein the pressed powder material has a weight loss rate of 5% or less after heating at 180°C for 3000 hours. Technical proposal 7 The compacted powder material according to any one of Technical Schemes 1 to 6, wherein the intervening phase is an unsaturated polyester resin. Technical proposal 8 The compacted powder material according to any one of Technical Schemes 1 to 6, wherein the intervening phase is a bismaleimide resin. Technical proposal 9 A rotating electric machine comprising the pressed powder material according to any one of Technical Schemes 1 to 8. Technical proposal 10 A rotating electric machine equipped with a magnetic wedge containing the pressed powder material described in any one of Technical Schemes 1 to 8. [Explanation of symbols]

[0144] 2a Recess 2b Convex part 4 Small magnetic metal particles 6 flat plane 8 Adherent metal 9 Covering layer 10 Flat magnetic metal particles 20 Intervening phase 22 Prescribed cross section 100 Compacted Powder Materials 102 plane 200 motor 300 motor core 400 Transformers 500 inductor 600 Generator (rotating electric machine) 610 Turbine 620 shaft 630 Second Stator 640 Second rotor 650 brushes

Claims

1. A plurality of flat magnetic metal particles having flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, with an average thickness of 10 nm or more and 100 μm or less, and an average ratio of the average length within the flat surfaces to the thickness being 5 or more and 10,000 or less; and an intervening phase present between the flat magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F), In the pressed powder material, in a predetermined cross section perpendicular to the plane of the pressed powder material, the orientation variation of the multiple flat magnetic metal particles is 30 degrees or more and 45 degrees or less, the proximity rate of the multiple flat magnetic metal particles is 3% or more and 10% or less, and the average curvature rate of the multiple flat magnetic metal particles contained in the pressed powder material is 0.01% or more and 0.6% or less.

2. 2. The compacted powder material according to claim 1, wherein the compacted powder material has a porosity of 0.01% or more and 10% or less.

3. The compacted powder material according to claim 1 or 2, wherein the compacted powder material has a difference in coercivity depending on the direction within a plane of the compacted powder material.

4. A pressed powder material according to any one of claims 1 to 3, wherein at least a portion of the surface of the flat magnetic metal particles is covered with a coating layer having a thickness of 0.1 nm to 1 μm and containing at least one third element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F).

5. The compacted powder material according to any one of claims 1 to 4, wherein the intervening phase contains a resin whose weight loss rate after heating at 180°C for 3000 hours is 5% or less.

6. The compacted powder material according to any one of claims 1 to 5, wherein the compacted powder material has a weight loss rate of 5% or less after being heated at 180°C for 3000 hours.

7. 7. The compacted powder material according to claim 1, wherein the intervening phase is an unsaturated polyester resin.

8. 7. The compacted powder material according to claim 1, wherein the intervening phase is a bismaleimide resin.

9. A rotating electric machine comprising the powder material according to any one of claims 1 to 8.

10. A rotating electric machine comprising a magnetic wedge containing the powder material according to any one of claims 1 to 8.

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