Plurality of flat magnetic metal particles, composite magnetic material, magnetic wedge, and rotating electric machine

Abstract

To provide a magnetic wedge and a rotating electric machine having excellent magnetic and mechanical properties.SOLUTION: In a magnetic wedge, a plurality of flat magnetic metal particles 10 have 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, an average ratio of the average length within the flat surface to the thickness of 2 or more and 10,000 or less, and the flat surface has a first portion 12 and a second portion 14 in which the flat surface is curved by 30 degrees or more.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a plurality of flat magnetic metal particles, a composite magnetic material, a magnetic wedge, and a rotating electric machine. [Background technology]

[0002] Typically, the coil windings of rotating electric machines are housed in core slots and supported and fixed by wedges installed at the slot openings. While non-magnetic materials are typically used for these wedges, discontinuities in the magnetic reluctance across the gap between the stator core and rotor core result in pulsation in the magnetic flux distribution on the surface of the core facing the wedge across the gap, resulting in increased harmonic loss. To reduce this harmonic loss, wedges with moderate magnetic properties (magnetic wedges) have long been used. Existing magnetic wedges generally use composite magnetic materials containing magnetic particles (mainly magnetic metal particles) in the intervening phase. The use of such magnetic wedges reduces harmonic loss and improves the efficiency of rotating electric machines. Figure 1 shows a schematic diagram of a magnetic wedge in use and its effects. Figure 1 shows a radial gap-type rotating electric machine as an example. In FIG. 1, magnetic wedges 100, coils 230, iron core teeth 250, and iron core slots 260 are shown.

[0003] It goes without saying that the higher the magnetic permeability of a magnetic wedge, the more effectively it can reduce harmonic loss. However, as shown in Figure 1, magnetic wedges are arranged to bridge adjacent core teeth, which has the disadvantage of increasing leakage magnetic flux flowing between the core teeth through the magnetic wedge. Furthermore, existing magnetic wedges have low saturation magnetization, which makes them prone to magnetic saturation. Furthermore, they also have large losses (high coercivity, resulting in high hysteresis loss, and low electrical resistivity, resulting in large eddy current loss), limiting the extent to which they can improve the efficiency of rotating electric machines. Furthermore, existing magnetic wedges have low permeability, which limits the extent to which they can improve the efficiency of rotating electric machines, and they are also insufficient in terms of mechanical properties (such as strength). Therefore, it is desirable to improve the saturation magnetization, permeability, loss, and strength of magnetic wedges. In particular, it is desirable to improve their magnetic and mechanical properties. Furthermore, as mentioned above, magnetic wedges generally use composite magnetic materials consisting of magnetic particles (mainly magnetic metal particles) and intervening phases, so it is desirable to improve the magnetic and mechanical properties of the magnetic metal particles and composite magnetic materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 58-6572 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a plurality of flat magnetic metal particles, a composite magnetic material, a magnetic wedge, and a rotating electric machine that have excellent magnetic properties and mechanical properties. [Means for solving the problem]

[0006] The flat magnetic metal particles of the embodiment have flat surfaces 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, an average ratio of the average length within the flat surfaces to the thickness of 2 or more and 10,000 or less, and a portion of the flat surfaces that is curved by 30 degrees or more. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing the use of a magnetic wedge and the effect of the magnetic wedge. [Figure 2] FIG. 3 is a conceptual diagram showing an example of how to determine the thickness of a flat magnetic metal particle in the first embodiment. [Figure 3] FIG. 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 in the first embodiment. [Figure 4] 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 in the first embodiment. [Figure 5] FIG. 1 is a schematic diagram showing the direction in which the coercive force was measured in the first embodiment, changing the direction every 22.5 degrees relative to the 360-degree angle within the flat surface of a flat magnetic metal particle. [Figure 6] 3 is an example of a micrograph of a plurality of flat magnetic metal particles according to the first embodiment. [Figure 7] 1 is a schematic diagram of a flat magnetic metal particle of the first embodiment. [Figure 8] FIG. 2 is a schematic diagram of a magnetic wedge according to the first embodiment. [Figure 9] 3 is a cross-sectional photograph example of the magnetic wedge of the first embodiment. [Figure 10] 3 is a cross-sectional photograph example of the magnetic wedge of the first embodiment. [Figure 11] 1 is a schematic diagram of a flat magnetic metal particle according to a first embodiment. [Figure 12] 3 is a cross-sectional photograph example of the magnetic wedge of the first embodiment. [Figure 13]3 is a cross-sectional photograph example of the magnetic wedge of the first embodiment. [Figure 14] 3 is a cross-sectional photograph example of the magnetic wedge of the first embodiment. [Figure 15] 1 shows an example of a micrograph of a plurality of flat magnetic metal particles of the first embodiment, and a micrograph of a plurality of flat magnetic metal particles of a comparative example. [Figure 16] 10 is an example of a micrograph of a plurality of flat magnetic metal particles according to the second embodiment. [Figure 17] FIG. 10 is a schematic diagram illustrating an example of a radial gap type rotating electric machine according to a third embodiment. [Figure 18] FIG. 10 is a schematic diagram showing an example of an axial gap type rotating electric machine according to a third embodiment. [Figure 19] FIG. 10 is a schematic diagram illustrating an example of a generator according to a third embodiment. [Figure 20] FIG. 10 is a schematic diagram illustrating an example of a linear motor according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals. In this specification, measurements are made at 25°C unless otherwise specified.

[0009] In this specification, the terms "axial direction," "rotational direction," and "radial direction" are defined relative to the rotor of the rotating electric machine. That is, "axial direction" refers to the direction along the rotational axis of the rotor, "rotational direction" refers to the direction around the rotational axis of the rotor (or the tangential direction thereof), and "radial direction" refers to the direction perpendicular to (perpendicular to) the rotational axis of the rotor.

[0010] (First embodiment) The flat magnetic metal particles of the embodiment have flat surfaces 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, an average ratio of the average length within the flat surfaces to the thickness of 2 or more and 10,000 or less, and have portions of the flat surfaces that are curved by 30 degrees or more.

[0011] The flat magnetic metal particles of the embodiment have an average flat surface length of 100 μm or more and 500 μm or less, a ratio of the maximum length to the minimum length of the flat surface of 1.2 or more, and a sharp outline.

[0012] The composite magnetic material of the embodiment is a composite magnetic material comprising a plurality of flat magnetic metal particles and an intervening phase, wherein the plurality of flat magnetic metal particles have flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and have an average thickness of 10 nm or more and 100 μm or less, an average ratio of the average length within the flat surfaces to the thickness of 2 or more and 10,000 or less, and include flat magnetic metal particles having portions whose flat surfaces are curved by 30 degrees or more, and the intervening phase is present between the plurality of flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

[0013] The composite magnetic material of the present embodiment is used, for example, as a magnetic wedge. In other words, the magnetic wedge of the present embodiment includes the composite magnetic material of the present embodiment.

[0014] The flat magnetic metal particles are flaky particles (flattened particles) that have a flaky shape (flattened shape).

[0015] 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 in the observed cross section of the flat magnetic metal particle along the flat surface, the thickness of each selected location can be measured, and the average value can be used. Alternatively, ten or more equally spaced locations can be selected in the observed cross section of the flat magnetic metal particle along the flat surface 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 used. Figure 2 is a conceptual diagram showing an example of how to determine the thickness of a flat magnetic metal particle in the first embodiment. Figure 2 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. It is preferable to measure as many points as possible, as this allows for obtaining average information. If the cross-sectional contour line is very 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.

[0016] Furthermore, the average thickness refers to the average value of the thicknesses of multiple flat magnetic metal particles and is distinct 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 more than 20 flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and use an average value for them. The average thickness of the flat magnetic metal particles is preferably 10 nm or more and 100 μm or less. It is more preferably 10 nm or more and 1 μm or less, and even more preferably 10 nm or more and 100 nm or less. It is also preferable that the flat magnetic metal particles include those with 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 10 nm or more and 100 nm or less. This is preferable because it allows for sufficiently small 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 surface, and magnetization easily progresses by rotational magnetization. When magnetization progresses by rotational magnetization, the magnetization tends to progress reversibly, so the coercive force becomes smaller, which is preferable because hysteresis loss can be reduced.

[0017] 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 3 is a conceptual diagram for explaining how to calculate the maximum and minimum lengths within the flat surface of a flat magnetic metal particle in the first embodiment. Figure 3 is a schematic diagram showing the maximum length a and minimum length b calculated using the above method for several flat magnetic metal particles. Like the average thickness, the maximum length a and minimum length b can be calculated by observing the flat magnetic metal particles using 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. It is also preferable to calculate the maximum length a and minimum length b for 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 an average value as much 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 thoroughly mix multiple flat magnetic metal particles and then attach them to tape, or to drop multiple flat magnetic metal particles from above and attach them to tape, and then perform observation or image analysis.

[0018] 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 calculation that does not capture the essence. Figure 4 is a conceptual diagram illustrating another example of how to determine the maximum and minimum lengths within the flat surface of a flat magnetic metal particle in the first embodiment. For example, in the case shown in Figure 4, 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 4. As such, the method of determining the maximum lengths a and b is not completely unique. Basically, it is acceptable to "consider the rectangle with the smallest area among the rectangles circumscribing the flat surface, and set 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 essence, the maximum length a and minimum length b can be calculated flexibly to capture the essence. The thickness t is defined as the length perpendicular to the flat surface. The ratio A of the average length in the flat plane 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.

[0019] The average ratio of the average length within the flat surface to the thickness of the flat magnetic metal particles is preferably 2 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.

[0020] 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.

[0021] It is preferable that the flat magnetic metal particles have a difference in coercivity depending on the direction within the flat surface. The larger the ratio of the difference in coercivity depending on the direction, the more preferable it is, and it is preferably 1% or more. More preferably, the ratio of the difference in coercivity is 10% or more, even more preferably 50% or more, and even more preferably 100% or more. The ratio of the difference in coercivity 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. Note that the coercivity can be evaluated using a vibrating sample magnetometer (VSM) or the like. When the coercivity is low, a coercivity 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.

[0022] 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 maximized and an angle where the coercive force is minimized, the particle is considered to have a coercive force difference. Figure 5 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 of a flat magnetic metal particle in the first embodiment. Note that Figure 5 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 particle with almost no coercive force difference. In materials with magnetic anisotropy within the flat plane, the coercive force varies depending on the direction within 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. Figure 5 shows a flat magnetic metal particle 10 and a flat plane 6.

[0023] The flat magnetic metal particles have a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni. It is preferable to select a composition that can achieve a higher saturation magnetization.

[0024] The elements can be easily analyzed by EDX (Energy Dispersive X-ray spectroscopy) or ICP (Inductively Coupled Plasma) optical emission spectroscopy.

[0025] The flat magnetic metal 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. This improves the thermal stability and oxidation resistance of the flat magnetic metal particles. Among these, Al and Si are particularly preferred because they easily dissolve in Fe, Co, and Ni, the main components of the flat magnetic metal particles, and contribute to improving thermal stability and oxidation resistance.

[0026] In order to induce magnetic anisotropy, one method is to make the crystallinity of the flat magnetic metal particles as amorphous as possible and then induce magnetic anisotropy in one direction in the plane using a magnetic field or strain. In this case, it is desirable to use a composition that makes it as easy to make the flat magnetic metal particles amorphous as possible. From this perspective, it is preferable that the magnetic metal contained in the flat magnetic metal particles contains at least one additive element selected from B (boron), Si (silicon), Al (aluminum), C (carbon), Ti (titanium), Zr (zirconium), Hf (hafnium), Nb (niobium), Ta (tantalum), Mo (molybdenum), Cr (chromium), Cu (copper), W (tungsten), P (phosphorus), N (nitrogen), Ga (gallium), and Y (yttrium). It is preferable that the additive element has a large difference in atomic radius from at least one first element selected from the group consisting of Fe, Co, and Ni. Furthermore, the additive element is preferably at least one first element selected from the group consisting of Fe, Co, and Ni, such that the mixing enthalpy of the additive element with the first element becomes negative. Furthermore, a multi-element system consisting of three or more elements, including the first element and the additive element, is preferable. Furthermore, semimetallic additive elements such as B and Si have a slow crystallization rate and tend to become amorphous, making them advantageous to incorporate into the system. From the above perspectives, B, Si, P, Ti, Zr, Hf, Nb, Y, Cu, etc. are preferable, and it is more preferable that the additive element includes one of B, Si, Zr, Hf, and Y. For example, it is preferable that the first element of the magnetic metal phase includes Fe and Co, and the additive elements include Si and B. Furthermore, it is preferable that the total amount of the additive element is 0.001 at% to 80 at% of the total amount of the first element and the additive element. More preferably, it is 5 at% to 80 at% and even more preferably, it is 10 at% to 40 at%. The larger the total amount of the added elements, the more the amorphization progresses and the easier it is to impart magnetic anisotropy, which is preferable (i.e., it is preferable from the viewpoint of low loss and high magnetic permeability), but on the other hand, it is not preferable in that the proportion of the magnetic metal phase decreases, which reduces the saturation magnetization. For these reasons, it is important to select the composition and the amount of added elements by comprehensively considering high saturation magnetization, low loss, high magnetic permeability, etc.

[0027] Figure 6 is an example of a micrograph of multiple flat magnetic metal particles of the first embodiment. Figure 6 shows multiple flat magnetic metal particles with an average ratio (a / b) of the maximum flat surface length a to the minimum flat surface length b of approximately 1.9. The ratio (a / b) of the maximum flat surface length a to the minimum flat surface length b of the multiple flat magnetic metal particles of the first embodiment is preferably 1.2 or more, and more preferably 1.5 or more. This results in excellent magnetic properties (high magnetic permeability, low coercive force, low loss, etc.). Furthermore, when made into a magnetic wedge, excellent magnetic and mechanical properties are obtained.

[0028] As shown in FIG. 6, the flat surface preferably has a curved portion, more preferably a portion curved by 30 degrees or more, and even more preferably a portion curved by 45 degrees or more. This allows for excellent magnetic properties (high magnetic permeability not only in one direction but also in other directions (or low coercivity and loss)). In particular, when the ratio (a / b) of the maximum length a to the minimum length b of the flat surface is 1.2 or more, more preferably 1.5 or more, and the flat surface has a curved portion, this makes it easier to achieve such excellent magnetic properties (high magnetic permeability not only in one direction but also in other directions (or low coercivity and loss)). Furthermore, when formed into a magnetic wedge, excellent magnetic and mechanical properties are obtained.

[0029] Furthermore, as shown in Figure 6, the contour of the flat magnetic metal particle of the first embodiment is sharp. Whether the contour is sharp and how sharp the contour is are defined by "surface roughness" and "circularity." Surface roughness is defined by the maximum height Ry of irregularities specified in JIS B0601. In other words, it is the value obtained by extracting a reference length from the roughness curve of the particle surface in the direction of the mean line, and measuring the distance between the peak line and the valley line of this extracted portion in the direction of the longitudinal magnification of the roughness curve. Surface roughness Ry is 0.1 μm or more and 500 μm or less, more preferably 1 μm or more and 100 μm or less, and even more preferably 10 μm or more and 100 μm or less. Circularity is an index that indicates whether the particle shape is close to a circle. When the area is S and the perimeter is L, the circularity is 4πS / L. 2The circularity is defined as: The closer the circularity is to 1, the closer the shape is to a circle. The circularity is 0.98 or less, more preferably 0.9 or less, even more preferably 0.8 or less, and even more preferably 0.7 or less. The lower limit of the circularity is preferably 0.01 or more, more preferably 0.1 or more. This results in excellent magnetic properties (high permeability, low coercivity, low loss, etc.). In particular, a sharpened outline makes it easier to impart magnetic anisotropy and to have a coercivity difference within the flat plane, which makes it easier to obtain excellent magnetic properties (high permeability, low coercivity, low loss, etc.), and is therefore preferable. Furthermore, when formed into a magnetic wedge, excellent magnetic and mechanical properties are obtained. In particular, a sharpened outline is preferable because it improves adhesion to the intervening phase (anchor- ing effect) and improves mechanical strength.

[0030] In multiple flat magnetic metal particles such as those shown in Figure 6, the magnetic metal phase contains Fe and Si, and it is preferable that the Si content be 1 wt% or more and 10 wt% or less of the entire magnetic metal phase ((weight of Si) / (weight of entire magnetic metal phase) x 100 (wt%) = 1 wt% or more and 10 wt% or less). More preferably, it is 4 wt% or more and 9 wt% or less, more preferably 5 wt% or more and 8 wt% or less, and even more preferably 6 wt% or more and 7 wt% or less. With such a composition, the flat surfaces have portions curved by 30 degrees or more, the average length of the flat surfaces is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of the flat surfaces is 1.2 or more, the contour is sharp, and magnetostriction can be extremely small, resulting in low-loss flat magnetic metal particles. In addition, the flat surface has a portion that is curved by 30 degrees or more, the average length of the flat surface is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of the flat surface is 1.2 or more, and the contour is sharp, which increases adhesion with the intervening phase (anchoring effect) and improves mechanical properties such as strength.

[0031] Furthermore, the flat magnetic metal particles of this embodiment include those having a thickness at the edge that is greater than the thickness at the center. Such a structure can enhance adhesion to the intervening phase (anchoring effect) and improve mechanical properties such as strength.

[0032] It is preferable 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).

[0033] 7 is a schematic diagram of a flat magnetic metal particle according to the first embodiment, showing a coating layer 9 and a flat magnetic metal particle 10.

[0034] 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 magnetic wedge 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 for the coating layer to have high electrical resistance, for example, a resistance value of 1 mΩ·cm or more.

[0035] 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. In this case, the magnetic permeability is also increased, 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).

[0036] 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 nm.

[0037] 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 electrical 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.

[0038] The intervening phase preferably contains a resin. Examples of resins that can be used include thermoplastic resins, thermosetting resins, polyester resins, vinyl ester resins, polyethylene resins, polystyrene resins, polyvinyl chloride resins, polyvinyl butyral resins, polyvinyl alcohol resins, polybutadiene resins, Teflon® 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 thereof. In particular, to achieve high thermal stability, it is preferable to include a silicone resin, polyimide resin, imide resin, or bismaleimide resin, which has high heat resistance. Epoxy resins, phenolic resins, and polyester resins are generally used resins that have relatively high heat resistance and strength, and are therefore preferred. It is also preferable that the material contains at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins. Furthermore, after 30 minutes of exposure to 120°C in the atmosphere and then one week of exposure to room temperature, the weight gain is preferably 1% or less, more preferably 0.1% or less. Furthermore, the water absorption rate as defined by ISO 62:1999 (JIS K7209:2000) is preferably 1% or less, more preferably 0.1% or less. To increase strength, materials such as fiber-reinforced plastics (FRP) containing fibers such as glass fiber, aramid fiber, carbon fiber, Zylon fiber, polyethylene fiber, and boron fiber are also preferred. 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. In addition, since the intervening phase surrounds the flat magnetic particles, the resin has excellent oxidation resistance and is less likely to deteriorate in magnetic properties due to oxidation of the flat magnetic metal particles, which is preferable.The type of resin can be identified by infrared spectroscopy (IR), nuclear magnetic resonance (NMR), etc.

[0039] Bismaleimide resins are preferred because they can be molded at relatively low temperatures (e.g., below 180°C) using general-purpose low-temperature hot press equipment. They are also preferred because they achieve high thermal stability and excellent mechanical properties after molding. Furthermore, they are easily combined (bonded) with flat magnetic metal particles, making them preferred for achieving excellent thermal stability as a composite material and mechanical properties such as strength and toughness. Furthermore, they are preferred because the intervening phase easily surrounds the flat magnetic particles, making them less susceptible to deterioration of magnetic properties due to oxidation of the flat magnetic metal particles.

[0040] The bismaleimide resin preferably has a glass transition temperature of 250° C. or higher, which is preferable because it provides high thermal stability and strength.

[0041] Specific examples of bismaleimide resins include 4,4'-diphenylmethane bismaleimide, phenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, 2,2'-diallyl bisphenol A, 4,4'-diphenyl Preferably, the resin contains bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, etc. (These monomers are polymerized to produce bismaleimide resins, so it is preferable to include the above as monomers.) This increases the thermal stability and strength, making it preferable.

[0042] Furthermore, the curing agent for curing the monomer preferably includes 4,4'-diaminodiphenylmethane, diaminodiphenyl ether, diaminodiphenyl sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, o,o'-diallylbisphenol A, etc. However, other types of curing agents may be used as long as they are capable of appropriately curing the monomer.

[0043] A preferred combination of monomer and curing agent is, for example, 4,4'-diphenylmethane bismaleimide and 4,4'-diaminodiphenylmethane. When 4,4'-diphenylmethane bismaleimide and 4,4'-diaminodiphenylmethane are contained, the ratio of 4,4'-diphenylmethane bismaleimide to 4,4'-diaminodiphenylmethane is preferably 1 to 3, more preferably about 2. A ratio of this or higher is preferred because it increases thermal stability and strength.

[0044] The molecular weight of the intervening phase is preferably 100 or more and 1000 or less, which is preferable because it increases the thermal stability and strength.

[0045] The polyimide resin preferably contains a repeating unit represented by the following chemical formula (1). [ka] (1) In the chemical formula (1), R preferably contains a biphenyl, triphenyl, or tetraphenyl structure, and R' preferably represents a structure having at least one aromatic ring within the structure.

[0046] Moreover, the polyimide resin more preferably has the following structural formula (2) or (3). [ka] (2) [ka] (3)

[0047] FIG. 8 is a schematic diagram of a magnetic wedge according to this embodiment. As shown in FIG. 8, the magnetic wedge may have not only a simple rectangular parallelepiped shape (with a rectangular cross section), but also various other cross-sectional shapes, such as a trapezoid, hexagon, or convex shape. The closer the magnetic wedge is positioned to the gap between the rotor and stator, the greater its effectiveness (improving the efficiency of the rotating electric machine). From this perspective, trapezoid, convex, and hexagonal shapes are preferable to rectangular shapes. Furthermore, from the perspective of "a shape that easily draws magnetic flux toward the magnetic wedge (thus improving the efficiency of the rotating electric machine)," trapezoid and convex shapes are preferable to hexagonal shapes. On the other hand, from the perspectives of ease of manufacturing and high material reliability (mechanical and thermal properties), rectangular shapes are most preferable, followed by trapezoid and hexagonal shapes. In this sense, the trapezoidal type is highly preferable because it can be easily placed close to the gap surface between the rotor and stator, and the trapezoidal shape makes it easy to draw the magnetic flux toward the magnetic wedge.Furthermore, it is easy to manufacture and can easily achieve high reliability as a material (mechanical properties, thermal properties).

[0048] Regardless of the shape, the three axial directions intersecting perpendicularly or perpendicularly to each other are defined as the width direction, thickness direction, and longitudinal direction. The longitudinal direction of a magnetic wedge is the direction in which the magnetic wedge is longer. For example, if the shape of the magnetic wedge is a roughly rectangular parallelepiped, the direction along the longest side of the roughly rectangular parallelepiped shape is determined as the longitudinal direction of the magnetic wedge. The thickness direction and width direction of a magnetic wedge are directions perpendicular to the longitudinal direction of the magnetic wedge. The thickness direction and width direction of a magnetic wedge can be distinguished as follows: If the magnetic wedge is installed inside a rotating electric machine, the magnetic wedge is removed from the inside of the rotating electric machine. Here, the rotation direction of the rotating electric machine is the width direction of the magnetic wedge. The thickness direction is the direction perpendicular to the width direction. On the other hand, if the magnetic wedge is not installed inside a rotating electric machine, the width direction is the direction closest to the average orientation direction of the flat magnetic metal particles at the center of the cross section perpendicular to the longitudinal direction. The thickness direction is perpendicular to the width direction. For cross sections perpendicular to the longitudinal direction, the end faces of the target magnetic wedge are avoided. For such cross sections, the target magnetic wedge is cut perpendicular to the longitudinal direction of the target magnetic wedge so that the cross section has a length of at least one-tenth of the longitudinal length of the target magnetic wedge. Furthermore, the center of the cross section formed by cutting is, for example, a region containing multiple flat magnetic metal particles at the geometric center of the cross section. Next, the cross section of the target magnetic wedge formed by cutting is observed using an optical microscope, SEM, or TEM. Then, for each flat magnetic metal particle observed in the cross section formed by cutting, the rectangle with the smallest area circumscribing each flat magnetic metal particle is considered, and the orientation direction is measured along the long side of that rectangle. However, some flat magnetic metal particles may have unclear particle contours during observation, making them difficult to evaluate. In other words, the particle contours may not be clearly identified through image analysis, and in such cases, the particle is excluded from observation.

[0049] Figure 9 is an example of a cross-sectional photograph of a magnetic wedge of the first embodiment. The cross-sectional photograph shows that an intervening phase is provided between multiple flat magnetic metal particles. It is preferable that the flat magnetic metal particles having a portion where the flat surface is curved by 30 degrees or more include those in which the maximum angle formed with adjacent flat magnetic metal particles is 30 degrees or more, and more preferably 45 degrees or more. Furthermore, even for flat magnetic metal particles whose flat surfaces are not curved by 30 degrees or more, it is preferable that the maximum angle between adjacent flat magnetic metal particles is 30 degrees or more, and more preferably 45 degrees or more. Figures 9(1), (2), and (3) are enlarged views of a portion of Figure 9. Figures 9(1) and (2) show the angles that flat magnetic metal particles having a portion whose flat surface is curved by 30 degrees or more make with adjacent flat magnetic metal particles. In (1), examples of the angle are 21 degrees and 46 degrees, with the maximum angle being 46 degrees. In (2), examples of the angle are 53 degrees and 59 degrees, with the maximum angle being 59 degrees. In (3), the angle formed by a flat magnetic metal particle whose flat surface is not curved by 30 degrees or more with an adjacent flat magnetic metal particle is shown. In (3), the angle formed is 80 degrees. In this way, the angle formed by all adjacent flat magnetic metal particles may be 30 degrees or more, or it is sufficient that the angle formed by only one of the adjacent flat magnetic metal particles is 30 degrees or more. It is also preferable that the magnetic wedge contains flat magnetic metal particles whose flat surfaces are aligned along the thickness direction, and more preferably, flat magnetic metal particles whose flat surfaces are at an angle of 0 to 45 degrees from the thickness direction of the magnetic wedge are present at the "widthwise end" of the magnetic wedge. Note that the "widthwise end" refers to the end of the width direction of the magnetic wedge, i.e., the area in the range of "10 times the average length of the flat magnetic metal particles" from the contour line in the thickness direction.

[0050] Figure 10 is an example cross-sectional photograph of the magnetic wedge of the first embodiment. Figure 10 is an enlarged view of a portion of the example cross-sectional photograph shown in Figure 9. The flat magnetic metal particle 10 has a first portion 12 including a first end 11 and a second portion 14 including a second end 13 and having the same length as or shorter than the first portion 12. The length of the first portion 12 is L1, and the length of the second portion 14 is L2. Here, the first portion and the second portion are determined, for example, as follows, with reference to FIG. 11 . For the first portion, when a line is drawn that is approximately parallel to the flat magnetic metal particle and includes the first end, the length of the line is defined as L1. Note that approximately parallel means that the angle between the line drawn along the flat magnetic metal particle and the flat magnetic metal particle is within 10 degrees, but this is merely a guideline and should be determined appropriately depending on the situation. Similarly, for the second portion, when a line is drawn that is approximately parallel to the flat magnetic metal particle and includes the second end, the length of the line is defined as L2. L2 is the same as or shorter than L1. Furthermore, the second portion 14 is preferably curved relative to the first portion 12, more preferably curved by 30 degrees or more, and even more preferably curved by 45 degrees or more. Furthermore, the length L2 of the second portion 14 is 100% or less of the length L1 of the first portion 12, but is preferably 0.1% or more and 100% or less, more preferably 1% or more and 90% or less, and even more preferably 1% or more and 80% or less.

[0051] The cross-sectional photograph example shown at the bottom of Figure 10 explains the definition of the curvature angle of the flat magnetic metal particle in the first embodiment. Straight lines are drawn from the first end 11 and the second end 13 along the flat surface of the flat magnetic metal particle. The angle at which these lines intersect with each other is defined as the curvature angle of the flat magnetic metal particle. In the case of the flat magnetic metal particle shown in Figure 10, the second portion 14 is curved at 68 degrees relative to the first portion 12. Furthermore, the first portion 12 is curved at 68 degrees relative to the second portion 14.

[0052] It is preferable that flat magnetic metal particles whose second portion 14 is curved at an angle of 30 degrees or more relative to the first portion 12 are contained in a number ratio of 1% or more among the multiple flat magnetic metal particles, more preferably 3% or more, even more preferably 5% or more, and even more preferably 5% or more and 50% or less. The proportion of curved flat magnetic metal particles is determined as follows. First, a cross section formed by cutting the magnetic wedge in question is observed using an optical microscope, SEM, or TEM. The cross section to be observed is a cross section that includes the width and thickness directions of the magnetic wedge (i.e., perpendicular to the length direction (longitudinal direction)), and is taken as the cross section at the center of the length in the longitudinal direction. Next, all flat magnetic metal particles contained in this entire cross section are counted, and the number of flat magnetic metal particles that have a portion where the flat surface is curved by 30 degrees or more is counted, and the proportion of the number (= number of curved flat magnetic metal particles / total number of flat magnetic metal particles × 100 (%)) is calculated.

[0053] 12 is an example of a cross-sectional photograph of the magnetic wedge of the first embodiment. The second portion 14 is curved by 90 degrees or more relative to the first portion 12. Furthermore, an imaginary line A drawn perpendicular to the flat surface of the first portion 12 passes through the second portion 14. In other words, the flat magnetic metal particles are bent significantly, so that the second portion 14 appears to cover the first portion 12 when viewed in the thickness direction. It is preferable that at least one flat magnetic metal particle, in which the second portion 14 is curved by 90 degrees or more relative to the first portion 12 and an imaginary line A drawn perpendicular to the flat surface of the first portion 12 passes through the second portion 14, is included among the multiple flat magnetic metal particles, more preferably at a ratio of 0.1% or more, and more preferably at a ratio of 0.1% to 10%.

[0054] 13 is an example of a cross-sectional photograph of a magnetic wedge according to the first embodiment. The first flat magnetic metal particle is located between the second flat magnetic metal particle and the third flat magnetic metal particle. The flat surfaces of the first, second, and third flat magnetic metal particles may have portions curved by 30 degrees or more. In Figure 13, the particles adjacent to the first flat magnetic metal particle are the second flat magnetic metal particle and the third flat magnetic metal particle. The distance between adjacent flat magnetic metal particles is preferably 0.1 to 100 times the thickness of the flat magnetic metal particle, more preferably 1 to 100 times, and even more preferably 1 to 10 times. As an example, Figure 13 shows that the distance between the first magnetic metal particle and the adjacent second or third flat magnetic metal particle is 0.1 to 100 times the thickness of the first flat magnetic metal particle. In this specification, the "distance between a flat magnetic metal particle and an adjacent flat magnetic metal particle" refers to the shortest distance between any part of a flat magnetic metal particle and any part of an adjacent flat magnetic metal particle. In such a case, for example, the intervening phase between the flat magnetic metal particle and the adjacent flat magnetic metal particle may have a gap. In addition, the location of the gap is not limited to between the flat magnetic metal particle and the adjacent flat magnetic metal particle.

[0055] FIG. 14 is a cross-sectional photograph of a magnetic wedge according to the first embodiment. FIG. 14 shows an example in which "flat magnetic metal particles having curved flat surfaces" are arranged in a different direction from adjacent "flat magnetic metal particles having curved flat surfaces." In other words, the flat magnetic metal particles are arranged with their curvatures in different directions. The cross-sectional photograph shown on the left of FIG. 14 shows the flat magnetic metal particles arranged with their curvatures in opposite directions. The cross-sectional photograph shown on the right of FIG. 14 shows the flat magnetic metal particles arranged with their curvatures in slightly different directions, though not completely opposite. In this embodiment, such an arrangement is preferable. This enhances adhesion to the intervening phase (anchor effect) and improves mechanical properties such as strength. It is also possible to achieve excellent magnetic properties not only in one direction but also in other directions. Furthermore, this type of arrangement can only be achieved by using "flat magnetic metal particles having curved portions on their flat surfaces," and cannot be achieved by using standard flat magnetic metal particles that do not have curved portions. When standard flat magnetic metal particles that do not have curved portions are molded to produce magnetic wedges, the flat surfaces are easily arranged so that they overlap, so that they may become curved when pressure is applied, for example, by press molding, but in principle, they are curved by overlapping the flat surfaces. In other words, "flat magnetic metal particles having curved portions on their flat surfaces" are arranged in the same direction as adjacent "flat magnetic metal particles having curved portions on their flat surfaces" (the curvature direction of each flat magnetic metal particle is the same). On the other hand, in this embodiment, since flat magnetic metal particles that are originally curved are used, when molding, the curved parts are not necessarily arranged in the same direction, and there is a fairly high probability that the curved parts will be arranged in different directions. In other words, it can be said that the structure shown in Figure 14 can only be realized by molding using particles with curved flat surfaces.

[0056] A method for manufacturing the magnetic wedge of this embodiment will be described below. Note that the manufacturing method is not particularly limited and will be described only as an example.

[0057] The first step is to produce a magnetic metal ribbon containing at least one first element selected from the group consisting of Fe, Co, and Ni. This step involves producing a ribbon or thin film using a film-forming device such as a roll quenching device or a sputtering device. In this case, when using a film-forming device, it is desirable to form a film with uniaxial anisotropy in the film plane by magnetic field deposition or rotational deposition. When using a film-forming device, it is possible to achieve a thin film, and the structure tends to be refined, making it easier to induce rotational magnetization. Therefore, when producing a material with rotational magnetization, it is desirable to use a film-forming method. A roll quenching device is suitable for mass synthesis and is therefore desirable when synthesizing bulk materials. A single-roll quenching device is simple and preferred.

[0058] In the method for producing a plurality of flat magnetic metal particles according to this embodiment, it is preferable to produce a ribbon containing Fe and Si, with the Si content being 1 wt% to 10 wt% of the entire magnetic metal phase. More preferably, it is 4 wt% to 9 wt%, more preferably 5 wt% to 8 wt%, and even more preferably 6 wt% to 7 wt%. This reduces magnetostriction and makes it easier to obtain a material with low magnetic loss. Fe-Si-based materials containing Fe and Si are generally brittle. However, by producing a ribbon (quenched ribbon) through quenching using a roll quenching device or the like, a ribbon exhibiting ductility and malleability can be produced. In producing a quenched ribbon, it is preferable to synthesize a ribbon of 20 μm or less by rapidly solidifying a molten liquid at a roll peripheral speed of, for example, 40 m / s or more, preferably 50 m / s or more. This makes it easier to exhibit ductility and malleability. The second step is to roll the magnetic metal ribbon, which is a quenched ribbon, to reduce the thickness of the flat magnetic metal particles. If the desired thickness has already been achieved in the first step, the rolling process can be omitted. The rolling may be cold rolling or hot rolling, and the rolling process is carried out until the desired thickness is achieved. Before performing this step, the ribbon may be cut to an appropriate size or crushed.

[0059] The third step is a heat treatment at a temperature of 50°C or higher and 1500°C or lower. In particular, heat treatment at a temperature of 800°C or higher, more preferably 900°C or higher, followed by rapid cooling, tends to produce an A2-type crystal structure, which makes Fe-Si-based materials more ductile and malleable. This also makes them more prone to bending. On the other hand, heat treatment at a temperature lower than 800°C or conventional slow cooling is not preferable because it is difficult to obtain an A2-type crystal structure (B2-type or DO3-type structures are more likely to be obtained), even when heat treatment is performed at a temperature higher than 800°C, resulting in poor ductility and malleability. In other words, a ribbon with extremely high ductility and malleability can only be obtained by selecting an Fe-Si-based material containing Fe and Si with the above-mentioned composition, producing a quenched ribbon under the above-mentioned conditions, and performing heat treatment under the above-mentioned conditions (rapid cooling after heat treatment). This makes it difficult to crush in the subsequent crushing process, resulting in curved, flat magnetic metal particles. Therefore, in order to obtain the curved, flat magnetic metal particles of this embodiment, it is necessary to select the composition, ribbon manufacturing conditions, and heat treatment conditions as specified above. Conversely, it is only by selecting such a combination that the curved, flat magnetic metal particles of this embodiment can be obtained. In the third step, the ribbon may be cut to an appropriate size to facilitate placement in an electric furnace for heat treatment. For example, cutting to an appropriate size may be performed using a mixer or the like. By performing this step, it is desirable to improve the pulverizability in the subsequent fourth step, the pulverization step. The heat treatment atmosphere is preferably a vacuum atmosphere with a low oxygen concentration, 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 magnetic metal ribbon is oxidized, by performing heat treatment in a reducing atmosphere, it is possible to reduce the oxidized metal and return it to metal. This also makes it possible to reduce a magnetic metal ribbon that has been oxidized and has reduced saturation magnetization, thereby restoring the saturation magnetization. In the case of an amorphous composition, if the crystallization of the magnetic metal ribbon progresses significantly due to heat treatment, the coercive force will increase and the magnetic permeability will decrease, so it is preferable to select conditions that suppress excessive crystallization. Furthermore, it is more desirable to carry out the heat treatment in a magnetic field. The stronger the applied magnetic field, the better, but it is preferable to apply a magnetic field of 1 kOe or more, and even more preferable to apply a magnetic field of 10 kOe or more. This is preferable because it allows magnetic anisotropy to be expressed in the plane of the magnetic metal ribbon, thereby achieving excellent magnetic properties.

[0060] The fourth step is to pulverize the heat-treated magnetic metal ribbon to produce flat magnetic metal particles. Prior to this pulverization, the magnetic metal ribbon or thin film may be cut to an appropriate size using a mixer or other device. In this step, pulverization is carried out using a pulverizer such as a mixer, bead mill, or planetary mill. Any type of pulverizer is acceptable. Examples include a mixer, planetary mill, bead mill, rotary ball mill, vibrating ball mill, stirring ball mill (attritor), jet mill, centrifuge, or a combination of mill and centrifugation. During pulverization, it is preferable to perform pulverization while cooling to a temperature below 0°C, as this facilitates pulverization. In particular, it is desirable to cool to liquid nitrogen temperature (77K) or dry ice temperature (194K), and among these, it is especially desirable to cool to liquid nitrogen temperature. This makes the magnetic metal ribbon more susceptible to low-temperature brittleness, making pulverization easier. In other words, this is preferable because pulverization can be performed efficiently without applying excessive stress or strain to the magnetic metal ribbon. However, in many cases, pulverization is sufficient without cooling, in which case cooling is not necessary.

[0061] In the fourth step, the thickness of the flat magnetic metal particles can be reduced by combining rolling (cold rolling, warm rolling, etc.) with simple pulverization. If the desired thickness is achieved by the fourth step, the rolling process can be omitted. Rolling can be performed simultaneously, or after pulverization, or after rolling. In this case, a device capable of applying strong gravitational acceleration is preferred, such as a mixer, planetary mill, bead mill, rotary ball mill, vibrating ball mill, stirring ball mill (attritor), jet mill, centrifuge, or a combination of mill and centrifugation. For example, a high-power planetary mill is preferred because it can easily apply gravitational accelerations of several tens of g. In the case of a high-power planetary mill, an inclined planetary mill is more preferred, in which the direction of the rotational gravitational acceleration and the direction of the revolutionary gravitational acceleration are not collinear but are angled. In a normal planetary mill, the direction of the gravitational acceleration due to rotation and the direction of the gravitational acceleration due to revolution are on the same line, but in an inclined planetary mill, the container rotates while tilted, so the direction of the gravitational acceleration due to rotation and the direction of the gravitational acceleration due to revolution are not on the same line but at an angle. This is preferable because it allows power to be transmitted to the sample efficiently, allowing for efficient milling and rolling. Furthermore, when considering mass production, a bead mill is preferable as it is easy to process large quantities.

[0062] It is desirable to perform the above cutting, crushing, and rolling (rolling is performed as needed, and not performed if not necessary), and in some cases repeat the cutting, crushing, and rolling processes to obtain flat magnetic metal particles of a predetermined thickness and a predetermined "average value of the ratio of the average length within the flat surface to the thickness." In this case, crushing and rolling to a thickness of 10 nm to 100 μm, more preferably 10 nm to 1 μm, and even more preferably 10 nm to 100 nm, is preferable, as this results in particles that are prone to rotational magnetization. The average ratio of the average length within the flat surface to the thickness is 2 or more and 10,000 or less, but in the flat magnetic metal particles of this embodiment, it is particularly preferable that it is 10 or more and 10,000 or less. Furthermore, it is preferable that the average length of the flat surface is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of the flat surface is 1.2 or more, and the outline is sharp; by adopting these configurations, it is possible to improve the magnetic properties and mechanical properties.

[0063] To achieve the degree of orientation of the flat magnetic metal particles as in this embodiment, it is effective to improve the slippage of the flat magnetic metal particles and increase their fluidity. Therefore, it is preferable that the average thickness of the flat magnetic metal particles is 10 μm to 30 μm, more preferably 10 μm to 20 μm, and the average ratio of the average length to the thickness of the flat magnetic metal particles is 10 to 100, more preferably 10 to 50.

[0064] Furthermore, it is desirable to heat treat the obtained flat magnetic metal particles (step 5) to adequately remove lattice distortion. This heat treatment is preferably carried out at a temperature of 50°C or higher and 1500°C or lower, and the heat treatment atmosphere is preferably a vacuum atmosphere with a low oxygen concentration, an inert atmosphere, or a reducing atmosphere, and more preferably a reducing atmosphere such as H2, CO2, or CH4. It is also more desirable to perform the heat treatment in a magnetic field. The reasons and details for these are the same as those for step 3, so a detailed explanation will be omitted here. However, unlike step 3, the heat treatment temperature is preferably 600°C or lower, and more preferably 500°C or higher and 600°C or lower. This makes it easier to obtain a B2-type, DO3-type, or a mixed crystal structure of B2-type and DO3-type, which is preferable because it reduces magnetic loss. To summarize, it is preferable to make the crystal structure A2 type when producing a quenched ribbon, and then to make the crystal structure B2 type, DO3 type, or a mixture of B2 type and DO3 type during heat treatment after pulverization. This makes it possible to obtain curved, flat magnetic metal particles and reduce magnetic loss. In other words, curved, low-loss flat magnetic metal particles can only be obtained by appropriately setting the composition, the heat treatment method (quenching) and temperature after ribbon production, and the heat treatment temperature after pulverization.

[0065] By subjecting the quenched ribbon to heat treatment at an appropriate temperature, the quenched ribbon can be deformed and pulverized to produce low-loss flat magnetic metal particles according to the present embodiment. As a comparative example, the left side of Figure 15 shows a micrograph of flat magnetic metal particles produced by pulverizing an amorphous quenched ribbon of Fe-Co-Si-B (FeCoB (at%)-4 wt% Si) in a mixer. The particle coercivity was approximately 0.1 Oe. Also, on the right side of Figure 15, a micrograph of flat magnetic metal particles produced in this embodiment by grinding a quenched ribbon of Fe-Si (the ratio of Si to the total FeSi is 6.5 wt%) in a mixer is shown. Although these flat magnetic metal particles include some that are partially curved, it was found that the particle coercivity is approximately 0.5 Oe, a low coercivity approaching that of low-coercivity amorphous Fe-Co-Si-B particles. Generally, when particles are curved, stress is applied, which increases the coercivity. However, by using an Fe-Si particle composition with low crystalline anisotropy and low magnetostriction, and by appropriately selecting the heat treatment conditions after milling, it is possible to create a B2, DO3, or mixed B2 and DO3 crystal structure, which allows for low coercivity even with a curved structure. Similarly, it was found that high magnetic permeability can be achieved.

[0066] Next, in the sixth step, the above-mentioned interstitial phase and magnetic metal particles are mixed to form a mixed powder of the interstitial phase and flat magnetic metal particles. Next, in the seventh step, the mixed powder of the interstitial phase and magnetic metal particles is molded. Heat treatment may also be performed before or after the above steps as appropriate. In other words, heat treatment may be performed before or after molding, or simultaneously with molding. Heat treatment may also be performed before or after processing. The heat treatment conditions are as described above. It is more preferable to perform heat treatment in a magnetic field. The reasons and details for these are the same as those for the third step, so explanation will be omitted here.

[0067] In the seventh step, it is preferable to use a method in which a press pressure is applied in a uniaxial direction, such as uniaxial press molding or hot press molding.

[0068] Furthermore, it is preferable to perform hot press molding after uniaxial press molding. The hot press temperature is preferably 50°C or higher and 1000°C or lower, more preferably 50°C or higher and 800°C or lower. The stronger the applied magnetic field, the better, but it is preferable to apply 1 kOe or higher, more preferably 10 kOe or higher. The pressing pressure is preferably 1 MPa or higher and 100 MPa or lower, more preferably 1 MPa or higher and 10 MPa or lower. Thereafter, it is preferable to perform heat treatment while applying a magnetic field. The heat treatment temperature is preferably 50°C or higher and 1000°C or lower, more preferably 50°C or higher and 800°C or lower. The stronger the applied magnetic field, the better, but it is preferable to apply 1 kOe or higher, more preferably 10 kOe or higher.

[0069] Next, in the eighth step, if necessary, a surface coating layer is formed on the surface of the molded magnetic wedge (this step is omitted if not necessary). In this step, an inorganic or organic material is coated on the surface of the magnetic wedge. The coating method is not particularly limited. When coating an organic material such as a resin, the coating is performed by an impregnation method, a dipping method, etc., and in some cases, it is also preferable to perform compression bonding using a hot press or the like after coating. When coating an inorganic material, the coating is performed by a gas phase method or a liquid phase method such as sol-gel, and in some cases, it is also preferable to perform compression bonding using a hot press or the like after coating. It is also preferable to perform heat treatment after coating to form a strong coating layer.

[0070] When measuring the coercive force depending on the direction within a plane parallel to the flat surface of the flat magnetic metal particle of the magnetic wedge, for example, the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the plane.

[0071] By having a coercive force difference within the plane of the magnetic wedge, 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.

[0072] In a plane parallel to the flat surface of the flat magnetic metal particle of the magnetic wedge, the larger the ratio of the coercive force difference depending on the direction, the better, and it is preferably 1% or more. More preferably, the ratio of the coercive force difference is 10% or more, even more preferably, the ratio of the coercive force difference is 50% or more, and even more preferably, the ratio of the coercive force difference is 100% or more. The ratio of the coercive force difference 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 in the flat surface.

[0073] 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. Measurements are performed by changing the direction of the measuring magnetic field within the plane of the magnetic wedge (within a plane parallel to the flat surface of the flat magnetic metal particle).

[0074] 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).

[0075] The effects of the flat magnetic metal particles and composite magnetic material (magnetic wedge) of this embodiment will be described. The magnetic wedge here is an example in which a resin is used as an intervening phase. The magnetic wedge of this embodiment includes curved flat magnetic metal particles, and the flat surfaces of the flat magnetic metal particles are more likely to be aligned parallel to the thickness direction of the magnetic wedge. On the other hand, in the magnetic wedge using flat magnetic metal particles of Fe-Co-Si-B (Fe70Co30B25 (at%)-4wt%Si) as a comparative example, the flat magnetic metal particles do not include curved flat magnetic metal particles, and the flat surfaces of the flat magnetic metal particles are more likely to be aligned parallel to the width direction of the magnetic wedge (i.e., they are more likely to be aligned perpendicular to the thickness direction of the magnetic wedge). Due to the above configuration, it was found that the coercive force in the thickness direction of the magnetic wedge of this embodiment is significantly reduced compared to the comparative example. This is because in this embodiment, the flat surfaces of the flat magnetic metal particles are more likely to be aligned parallel to the thickness direction of the magnetic wedge, which makes it possible to significantly reduce loss in the thickness direction (the direction in which magnetic flux mainly flows) in the rotating electrical machine. Similarly, the magnetic permeability can be increased in the thickness direction. This allows for efficient magnetic flux conduction in rotating electrical machines. Furthermore, the magnetic wedge of this embodiment contains many areas where flat surfaces are aligned in the width and length directions, so the flat surfaces resist stress, increasing the strength in the width and length directions. Furthermore, because the curved flat surfaces are partially aligned in the thickness direction, the strength in the thickness direction is also increased. As a result, high strength can be achieved in all directions: width, length, and thickness. In contrast, in the comparative example, the flat surfaces of the non-curved flat magnetic metal particles are aligned in the width and length directions, so the strength in the width and length directions is high, but the strength in the thickness direction is significantly reduced (strength is reduced in directions parallel to the flat surfaces because the flat surfaces are easily cleaved).

[0076] As described above, according to this embodiment, it is possible to provide flat magnetic metal particles and magnetic wedges with excellent properties.

[0077] (Second embodiment) The flat magnetic metal particles of this embodiment differ from those of the first embodiment in that the average length of the flat surfaces is 1 μm or more and 200 μm or less, the ratio of the maximum length to the minimum length of the flat surfaces is 1 or more and 2 or less, and the outline is smooth. Here, description of content that overlaps with the first embodiment will be omitted.

[0078] 16 is an example of a micrograph of the flat magnetic metal particles of this embodiment. Compared to the flat magnetic metal particles of the first embodiment, the flat magnetic metal particles of this embodiment have an average flat surface length of 1 μm or more and 200 μm or less. The average ratio of the average length within the flat surface to the thickness is 2 or more and 10,000 or less, and in the flat magnetic metal particles of this embodiment, it is particularly preferable that it is 2 or more and 10 or less.

[0079] Furthermore, compared to the flat magnetic metal particles of the first embodiment, the multiple flat magnetic metal particles of this embodiment have a ratio of the maximum length to the minimum length of the flat surface of 1 or more and 2 or less, more preferably 1 or more and 1.5 or less. Note that Figure 16 shows multiple flat magnetic metal particles whose ratio (a / b) of the maximum length a to the minimum length b of the flat surface is approximately 1.3 on average.

[0080] Furthermore, compared to the flat magnetic metal particles of the first embodiment, the flat magnetic metal particles of this embodiment have smoother contours. As mentioned above, the smoothness of the contours is defined by "surface roughness" and "circularity." Surface roughness is defined as the maximum height Ry of the irregularities specified in JIS B0601. Surface roughness Ry is 0.1 μm or more and 100 μm or less, more preferably 0.1 μm or more and 10 μm or less. Circularity is an index that indicates whether the particle shape is close to a circle. When the area is S and the perimeter is L, the circularity is 4πS / L 2 The closer the circularity is to 1, the closer the shape is to a circle. The circularity is preferably 0.5 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and even more preferably 0.9 or more. Generally, as the particle size of magnetic particles decreases, the ratio of pinning sites per unit volume increases, which is undesirable as the coercive force increases. In this embodiment, the particle size is also smaller than in the first embodiment, so the coercive force is likely to increase, but by adopting the structure described above (the ratio of the maximum length to the minimum length of the flat surface is between 1 and 2, and the contour is smooth (surface roughness and circularity are within the ranges described above)), the stress applied to the particles can be minimized, and a relatively small coercive force (i.e., low loss) and high magnetic permeability can be achieved despite the small particle size.

[0081] Furthermore, the flat magnetic metal particles of this embodiment include those having a thickness at the edge that is greater than the thickness at the center. Such a structure can enhance adhesion to the intervening phase (anchoring effect) and improve mechanical properties such as strength. To summarize, the average length of the flat surface is 1 μm or more and 200 μm or less, the average ratio of the average length within the flat surface to the thickness is 2 or more and 10,000 or less, and particularly preferably 2 or more and 10 or less, the ratio of the maximum length to the minimum length of the flat surface is 1 or more and 2 or less, more preferably 1 or more and 1.5 or less, and it is preferable that the contours are smooth.By adopting these configurations, it is possible to improve the magnetic and mechanical properties.

[0082] The flat magnetic metal particles of this embodiment can be manufactured, for example, by controlling the ribbon production conditions, the pulverization conditions using a mixer or the like, the rolling conditions, the heat treatment conditions, etc., in the manufacturing process of the flat magnetic metal particles of the first embodiment. In particular, it is preferable to reduce the rotation speed of the mixer or the like to reduce the stress and then perform pulverization for a long period of time, since this applies a continuous pulverization and deformation stress to the flat magnetic metal particles. Furthermore, during rolling, not only is the average thickness and the average value of the ratio of the average length within the flat surface to the thickness controlled, but deformation stress is also applied to the flat magnetic metal particles, making it easier to obtain the structure of this embodiment.

[0083] As described above, this embodiment also makes it possible to provide flat magnetic metal particles and magnetic wedges with excellent properties.

[0084] (Third embodiment) The rotating electric machine of this embodiment includes the magnetic wedge of the first embodiment. Therefore, description of the same content as in the first and second embodiments will be omitted. In this specification, the rotating electric machine is a concept that includes all of an electric motor (motor), a generator (generator), and a motor-generator that functions as both a motor and a generator as needed.

[0085] FIG. 17 shows an example of a radial gap motor according to this embodiment. A radial gap motor includes a rotor and a stator positioned radially opposite the rotor with a predetermined gap between them. In FIG. 17, the rotor is positioned inside the stator, but it may be positioned outside. The rotor includes a rotor core and a shaft and is supported for rotation. The stator includes a stator core, a field coil inserted into the slots in the stator core, and magnetic wedges held in the wedge grooves at the slot openings. While FIG. 17 shows an example in which the magnetic wedges are positioned as in the first embodiment, this is not limiting. In a radial gap rotating electric machine, the stator is positioned radially opposite the rotor with a predetermined gap between them, so the "gap plane" is a plane parallel to a cylindrical surface centered on the rotor's rotation axis. Therefore, the radial direction is perpendicular to the gap plane, and the axial direction and rotation direction are parallel to the gap plane. In FIG. 17, flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, rotating electric machine 200, rotor 210, stator 220, coil 230, gap surface 240, and iron core teeth 250 are shown.

[0086] By arranging the magnetic wedges of the first embodiment, it is possible to reduce harmonic loss occurring on the rotor surface while suppressing leakage magnetic flux. In addition, the magnetic flux passing through the air gap increases, which increases the torque of the radial gap motor. High efficiency can be achieved by either or both of the above loss reduction effect and torque increase effect.

[0087] The radial gap motor may be one having a conductor in the rotor (induction motor), one having a permanent magnet (permanent magnet motor), or one having a magnetic material (reluctance motor).

[0088] FIG. 18 shows an example of an axial gap motor according to this embodiment. An axial gap motor includes a rotor and a stator positioned opposite the rotor across a predetermined axial gap. The stator includes a stator core, field coils inserted into slots in the stator core, and magnetic wedges held in wedge grooves at the slot openings. The magnetic wedges according to this embodiment reduce harmonic losses on the rotor surface while suppressing leakage flux. Furthermore, the increased magnetic flux passing through the gap increases the torque of the axial gap motor. These factors contribute to high efficiency. While the rotor is positioned between two stators in FIG. 18, it may be positioned on one or both sides of a single stator. In an axial gap rotating electric machine, the stator faces the rotor across a predetermined axial gap, so the "gap plane" is a plane perpendicular to the rotor's rotation axis. Therefore, the axial direction is perpendicular to the gap surface, and the rotation direction and radial direction are parallel to the gap surface. 18 shows flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, a rotating electric machine 200, a rotor 210, coils 230, gap surfaces 240, iron core teeth 250, a stator 270, and a shaft 280.

[0089] FIG. 19 is a schematic diagram showing an example of a generator according to this embodiment. A generator typically includes a rotor with excitation coils housed in slots in the rotor core (although a rotor using permanent magnets as an excitation source may also be used) and a stator with armature coils housed in slots in the stator core. By rotating the rotor and passing an excitation current through the excitation coils, electric power is generated in the armature coils. The rotor includes a rotor core, a field coil inserted in the slots of the rotor core, and magnetic wedges held in wedge grooves at the slot openings, and is supported for rotation by bearings. The placement of the magnetic wedges according to this embodiment makes it possible to reduce harmonic losses occurring on the surface of the stator while suppressing an increase in leakage flux. Furthermore, because the magnetic flux passing through the air gap and interlinking with the armature coils increases, the generated voltage induced in the armature coils increases. As a result, high efficiency can be achieved. In Figure 19, magnetic wedges are arranged at the slot openings of the rotor core, but they may also be arranged at the slot openings of the stator core. Also, while the figure shows a wound-type generator with an excitation coil in the rotor, a permanent magnet-type generator with a permanent magnet in the rotor may also be used. In this case, the magnetic wedges are arranged at the slot openings of the stator core. Figure 19 shows flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, a rotating electric machine 200, a rotor 210, a stator core 222, an excitation coil 232, an armature coil 234, an air gap surface 240, and iron core teeth 250.

[0090] Since a linear motor is a flat-plate structure developed from a radial gap motor, the magnetic wedge of the present invention can also be applied to the linear motor. Specifically, the stator may include a stator core and a field coil inserted into slots in the stator core, with a magnetic wedge provided at the slot opening. Figure 20 is a schematic diagram showing an example of a linear motor according to this embodiment. In a linear motor, the moving direction of the mover, the direction perpendicular to the moving direction of the mover, and the direction perpendicular to the stator correspond to the rotation direction, axial direction, and radial direction of the radial gap motor, respectively. By using the magnetic wedge of this embodiment, it is possible to reduce harmonic losses generated on the mover surface while suppressing an increase in leakage magnetic flux. Furthermore, the increased magnetic flux passing through the air gap improves the thrust of the linear motor. As a result, high efficiency can be achieved. In FIG. 20, flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, stator 220, coil 230, gap surface 240, iron core teeth 250, and mover 290 are shown.

[0091] As described above, the rotating electric machine of this embodiment can suppress the increase in leakage flux due to the use of magnetic wedges and effectively alleviate the pulsation of the magnetic flux distribution on the surface of the iron core, thereby achieving high efficiency. Note that the slot shape of the rotating electric machine of this embodiment may be semi-closed slots, but is preferably open slots. This is preferable because harmonic loss can be significantly reduced.

[0092] The rotating electric machine of this embodiment can be applied to transportation systems such as railways, electric vehicles, and hybrid cars; social systems such as elevators and air conditioners; industrial systems such as robots, pumps, compressors, and fans; energy systems such as thermal power generators, hydroelectric generators, wind power generators, nuclear power generators, and geothermal power generators; and home appliances such as washing machines, thereby enabling high system efficiency. In particular, large-capacity industrial machines generally employ open slots, and therefore are preferably provided with the magnetic wedge of the first embodiment. Furthermore, traction motors for railways use form-wound coils due to the need to withstand high voltages and vibrations, and therefore employ open slots, and therefore are preferably provided with the magnetic wedge of the first embodiment.

[0093] In railways, the loss in the rotating electric machine accounts for about half of the power consumption when the train is running, so reducing the loss in the rotating electric machine has a significant effect on improving efficiency. Also, in electric vehicles and hybrid cars, the efficiency of the main motor can be improved by using the magnetic wedge of the first embodiment, thereby extending the cruising range.

[0094] The technology is expected to be highly effective in hydroelectric generators, especially variable-speed pumped-storage generators, and also in wind power generators.

[0095] (Example) Examples 1 to 14 will be described in more detail below in comparison with Comparative Examples 1 and 2.

[0096] Example 1 First, a ribbon of Fe-Si (Si / FeSi = 6.5 wt%) was produced using a single-roll quenching device. The resulting ribbon was then heat-treated at 1000°C in a H2 atmosphere and then quenched. The crystal structure of the Fe-Si magnetic metal phase was confirmed to be A2 type. The ribbon was then crushed using a mixer to obtain flat magnetic metal particles. The resulting flat magnetic metal particles were then heat-treated at 500°C in a H2 atmosphere. After heat treatment, the crystal structure of the Fe-Si magnetic metal phase was confirmed to be a mixed crystal structure of B2 and DO3 types. After classification and sorting, the resulting flat magnetic metal particles were confirmed to have an average thickness of 15 μm, an average flat plane length of 250 μm, and an average ratio of the average flat plane length to the thickness of approximately 17. After heat treatment, the flat magnetic metal particles were mixed with resin and hot-press molded to produce a composite magnetic material. Furthermore, it was confirmed that the proportion of flat magnetic metal particles with flat surfaces curved by 30 degrees or more was 1%, the ratio of the maximum length to the minimum length of the flat surfaces was 1.2 or more, and the contours were sharp.

[0097] Example 2 This is almost the same as Example 1, except that the crushing conditions were adjusted using a mixer device, and the flat magnetic metal particles were classified and sorted to ensure that the number of flat magnetic metal particles with portions of the flat surface curved by 30 degrees or more was 8%.

[0098] Example 3 This is almost the same as Example 1, except that the proportion of flat magnetic metal particles having a flat surface curved by 30 degrees or more was set to 27% by adjusting the grinding conditions using a mixer device and by classifying and selecting the flat magnetic metal particles.

[0099] Example 4 This is almost the same as Example 1, except that the proportion of flat magnetic metal particles having a flat surface curved by 30 degrees or more was set to 48% by adjusting the grinding conditions using a mixer device and by classifying and selecting the flat magnetic metal particles.

[0100] Example 5 This is almost the same as Example 1, except that the proportion of flat magnetic metal particles having a flat surface curved by 30 degrees or more was set to 52% by adjusting the grinding conditions using a mixer device and by classifying and selecting the flat magnetic metal particles.

[0101] Example 6 After producing the ribbon, it is rolled, and the grinding conditions are adjusted using a mixer device, and the flat magnetic metal particles are classified and selected.The final flat magnetic metal particles are almost the same as those in Example 1, except that they have an average thickness of 10 nm, an average flat surface length of 100 μm, an average ratio of the average length within the flat surface to the thickness of 10,000, and a number percentage of multiple flat magnetic metal particles with flat surfaces curved at 30 degrees or more of 44%.

[0102] Example 7 After producing the ribbon, it is rolled, and the grinding conditions are adjusted using a mixer device, and the flat magnetic metal particles are classified and selected.The final flat magnetic metal particles are almost the same as in Example 1, except that they have an average thickness of 1 μm, an average flat surface length of 500 μm, an average ratio of the average length within the flat surface to the thickness of 500, and a number percentage of multiple flat magnetic metal particles with portions of the flat surface curved by 30 degrees or more of 42%.

[0103] Example 8 By adjusting the grinding conditions using a mixer and classifying and selecting the flat magnetic metal particles, the final flat magnetic metal particles were confirmed to have an average thickness of 15 μm, an average flat surface length of 75 μm, an average ratio of the average length within the flat surface to the thickness of 5, a ratio of the maximum length to the minimum length of the flat surface of 1 or more and 2 or less, a smooth outline, and the proportion of multiple flat magnetic metal particles having a flat surface curved by 30 degrees or more was 1%.This is almost the same as Example 1, except that it was confirmed that the final flat magnetic metal particles had an average thickness of 15 μm, an average flat surface length of 75 μm, an average ratio of the average length within the flat surface to the thickness of 5, a maximum length to minimum length of 1 or more and 2 or less, a smooth outline, and a proportion of 1% of the flat magnetic metal particles having a flat surface curved by 30 degrees or more.

[0104] Example 9 This is almost the same as Example 8, except that the proportion of multiple flat magnetic metal particles having a flat surface curved by 30 degrees or more was set to 7% by adjusting the grinding conditions using a mixer and classifying and selecting the flat magnetic metal particles.

[0105] Example 10 This is almost the same as Example 8, except that by adjusting the grinding conditions using a mixer and by classifying and selecting the flat magnetic metal particles, the proportion of flat magnetic metal particles having parts whose flat surfaces are curved by 30 degrees or more was set to 26%.

[0106] Example 11 This is almost the same as Example 8, except that by adjusting the grinding conditions using a mixer and by classifying and selecting the flat magnetic metal particles, the proportion of flat magnetic metal particles having parts whose flat surfaces are curved by 30 degrees or more was set to 46%.

[0107] Example 12 This is almost the same as Example 8, except that by adjusting the grinding conditions using a mixer and by classifying and selecting the flat magnetic metal particles, the proportion of flat magnetic metal particles having parts whose flat surfaces are curved by 30 degrees or more was set to 51%.

[0108] Example 13 After producing the ribbon, it is rolled, and the grinding conditions are adjusted using a mixer device, and the flat magnetic metal particles are classified and selected.The final flat magnetic metal particles are almost the same as those in Example 8, except that they have an average thickness of 0.2 μm, an average flat surface length of 1 μm, an average ratio of the average length within the flat surface to the thickness of 5, and a proportion of multiple flat magnetic metal particles with flat surfaces curved at 30 degrees or more of 35%.

[0109] Example 14 By adjusting the ribbon production conditions, adjusting the grinding conditions using a mixer, and classifying and selecting the flat magnetic metal particles, the final flat magnetic metal particles were almost the same as those in Example 8, except that the average thickness of the flat magnetic metal particles was 100 μm, the average length of the flat surfaces was 200 μm, the average ratio of the average length within the flat surfaces to the thickness was 2, and the proportion of multiple flat magnetic metal particles having parts where the flat surfaces were curved by 30 degrees or more was 5%.

[0110] (Comparative Example 1) First, a ribbon of Fe-Co-Si-B (Fe70Co30B25 (at%)-4 wt% Si) was produced using a single-roll quenching device. The resulting ribbon was then heat-treated at 300°C in a H2 atmosphere. Next, this ribbon was pulverized using a mixer to obtain flat magnetic metal particles. The resulting flat magnetic metal particles were classified and sorted to confirm that they had an average thickness of 15 μm, an average flat plane length of 250 μm, and an average ratio of the average flat plane length to the thickness of approximately 17. The resulting flat magnetic metal particles were then mixed with resin and molded. During molding, a press pressure was applied in one axial direction, while a magnetic field was applied in a direction parallel to the press pressure application direction. Hot press molding was then performed to produce a composite magnetic material. Note that no flat magnetic metal particles with flat planes curved by more than 30 degrees were observed.

[0111] (Comparative Example 2) This was almost the same as Comparative Example 1, except that by adjusting the grinding conditions using a mixer and by classifying and selecting the flat magnetic metal particles, the average thickness of the final flat magnetic metal particles was 15 μm, the average length of the flat surfaces was 75 μm, and the average ratio of the average length within the flat surfaces to the thickness was 5. However, no flat magnetic metal particles were found with portions of the flat surfaces curved by more than 30 degrees.

[0112] Table 1 shows the average thickness, average length of the flat surfaces, average ratio of the average length within the flat surfaces to the thickness, and the proportion of flat magnetic metal particles having portions whose flat surfaces are curved by 30 degrees or more for the composite magnetic material of this embodiment, along with comparative examples 1 and 2.

[0113] Table 2 shows the magnetic permeability of the composite magnetic material of this embodiment, the degree of efficiency improvement as a rotating electrical machine, and the strength, together with Comparative Examples 1 and 2.

[0114] (1) Magnetic permeability: The magnetic permeability at 100 Hz was measured in the direction midway between the width direction and the thickness direction of the composite magnetic material. The magnetic permeabilities of Examples 1 to 7 are shown as ratios based on the magnetic permeability of Comparative Example 1. The magnetic permeabilities of Examples 8 to 14 are shown as ratios based on the magnetic permeability of Comparative Example 2.

[0115] (2) Degree of efficiency improvement as a rotating electrical machine: Using a standard radial gap motor as a motif, the efficiency when a non-magnetic wedge is used is taken as the standard, and the degree of efficiency improvement when the composite materials of the examples and comparative examples are used as magnetic wedges is calculated. The degree of efficiency improvement of Examples 1 to 7 is shown as a ratio based on the degree of efficiency improvement of Comparative Example 1. The degree of efficiency improvement of Examples 8 to 14 is shown as a ratio based on the degree of efficiency improvement of Comparative Example 2.

[0116] (3) Strength: A commercially available composite magnetic material in which spherical magnetic metal particles are dispersed was used as a comparative sample. This comparative sample is a material in which Fe powder is dispersed isotropically in three dimensions. The flexural strength of the examples, comparative examples, and comparative samples was measured at 25°C, and the strength is expressed as a ratio to the flexural strength of the comparative sample at 25°C (= flexural strength of evaluation sample at 25°C / flexural strength of comparative sample at 25°C). The flexural strength was evaluated in three directions: width, length, and thickness of the sample (magnetic wedge).

[0117] [Table 1]

[0118] [Table 2]

[0119] From Table 2, it can be seen that Examples 1 to 7 have superior properties in terms of magnetic permeability and degree of efficiency improvement as a rotating electric machine compared to Comparative Example 1. Similarly, it can be seen that Examples 8 to 14 have superior properties in terms of magnetic permeability and degree of efficiency improvement as a rotating electric machine compared to Comparative Example 2. It is believed that the composite magnetic materials of Examples 1 to 14 were able to efficiently guide magnetic flux in a rotating electric machine (improving magnetic permeability and efficiency) by having "plurality of flat magnetic metal particles having portions where the flat surfaces are curved by 30 degrees or more." Furthermore, Comparative Examples 1 and 2 not only lack "multiple flat magnetic metal particles having portions where the flat surfaces are curved by 30 degrees or more," but also have the flat surfaces of the non-curved flat magnetic metal particles aligned in the width and length directions. Therefore, although the strength in the width and length directions is high (the flat surfaces resist stress, resulting in high strength), the strength in the thickness direction is significantly low (strength is low in directions parallel to the flat surfaces, due to the tendency for the flat surfaces to cleave). In contrast, in Examples 1 to 14, which contain "multiple flat magnetic metal particles having portions where the flat surfaces are curved by 30 degrees or more," the curved flat surfaces are partially aligned in the thickness direction, resulting in a significant improvement in strength in the thickness direction. This demonstrates that high strength can be achieved in all directions: width, length, and thickness. In addition, in Examples 5 and 12, the proportion of "multiple flat magnetic metal particles having portions whose flat surfaces are curved by 30 degrees or more" exceeds 50%, which slightly reduces the above-mentioned effects, but is still preferable because it improves magnetic permeability, the degree of efficiency improvement as a rotating electric motor, and strength in the thickness direction compared to the comparative examples. From the above, it was found that a composite magnetic material containing "multiple flat magnetic metal particles having portions where the flat surface is curved by 30 degrees or more" has excellent properties in terms of magnetic permeability and the degree of efficiency improvement as a rotating electric motor when used as a magnetic wedge, and also has high strength in all directions: width, length, and thickness.

[0120] 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.

[0121] The above-described embodiments can be summarized as the following technical proposals. (Technical proposal 1) 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, an average ratio of the average length within the flat surface to the thickness of 2 or more and 10,000 or less, and having a portion where the flat surface is curved by 30 degrees or more. (Technical proposal 2) A plurality of flat magnetic metal particles as described in technical proposal 1, wherein the average length of the flat surface is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of the flat surface is 1.2 or more, and the outline is sharp. (Technical proposal 3) A plurality of flat magnetic metal particles described in technical proposal 1, wherein the average length of the flat surface is 1 μm or more and 200 μm or less, the ratio of the maximum length to the minimum length of the flat surface is 1 or more and 2 or less, and the outline is smooth. (Technical proposal 4) A plurality of flat magnetic metal particles according to any one of Technical Schemes 1 to 3, in which the thickness of the end is greater than the thickness of the center. (Technical proposal 5) A plurality of flat magnetic metal particles according to any one of Technical Schemes 1 to 4, wherein the magnetic metal phase contains Fe and Si, and Si is 1 wt% or more and 10 wt% or less of the entire magnetic metal phase. (Technical proposal 6) A composite magnetic material comprising a plurality of flat magnetic metal particles and an intervening phase, wherein the plurality of flat magnetic metal particles have flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and have an average thickness of 10 nm to 100 μm, an average ratio of the average length within the flat surfaces to the thickness of 2 to 10,000, and the flat surfaces include flat magnetic metal particles having portions curved by 30 degrees or more, and the intervening phase is present between the plurality of flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). (Technical proposal 7) A composite magnetic material according to technical proposal 6, wherein the average length of the flat surface is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of the flat surface is 1.2 or more, and the contour is sharp. (Technical proposal 8) A composite magnetic material according to technical proposal 6, wherein the average length of the flat surface is 1 μm or more and 200 μm or less, the ratio of the maximum length to the minimum length of the flat surface is 1 or more and 2 or less, and the contour is smooth. (Technical proposal 9) A composite magnetic material according to any one of technical proposals 6 to 8, which contains flat magnetic metal particles whose end thickness is greater than the thickness of the center. (Technical proposal 10) A composite magnetic material according to any one of Technical Schemes 6 to 9, wherein the magnetic metal phase contains Fe and Si, and the Si content is 1 wt% or more and 10 wt% or less of the entire magnetic metal phase. (Technical proposal 11) A composite magnetic material described in any one of Technical Schemes 6 to 10, wherein the flat magnetic metal particles having the curved portion are contained in a number ratio of 1% or more among the plurality of flat magnetic metal particles. (Technical proposal 12) A composite magnetic material described in any one of Technical Proposals 6 to 11, wherein the flat magnetic metal particles having the curved portions include those whose maximum angle with adjacent flat magnetic metal particles is 30 degrees or more and whose flat surfaces are aligned in the thickness direction. (Technical proposal 13) A magnetic wedge comprising the composite magnetic material described in any one of Technical Schemes 6 to 12. (Technical proposal 14) A rotating electric machine comprising the composite magnetic material according to any one of Technical Schemes 6 to 12. [Explanation of symbols]

[0122] 6: flat surface 9: Covering layer 10: Flat magnetic metal particles 11:First end 12: 1st part 13:Second end 14:Second part 20: Intervening phase 22 :Void 100:Magnetic wedge 200: Rotating electric machine 210: Rotor 220: Stator 222: Stator core 230: Coil 232: Excitation coil 234: Armature coil 240 :Void surface 250: Iron core teeth 260: Core slot 270: Stator 280: Axis 290: Mover A: Imaginary line

Claims

1. 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, an average ratio of the average length within the flat surface to the thickness of 2 or more and 10,000 or less, and a portion of the flat surface curved by 30 degrees or more.

2. 2. A plurality of flat magnetic metal particles according to claim 1, wherein the average length of the flat surfaces is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of the flat surfaces is 1.2 or more, and the outline is sharp.

3. A plurality of flat magnetic metal particles according to claim 1, wherein the average length of the flat surfaces is 1 μm or more and 200 μm or less, the ratio of the maximum length to the minimum length of the flat surfaces is 1 or more and 2 or less, and the outline is smooth.

4. 2. A plurality of flat magnetic metal particles according to claim 1, wherein the thickness of the end portion is greater than the thickness of the center portion.

5. 2. A plurality of flat magnetic metal particles according to claim 1, wherein the magnetic metal phase contains Fe and Si, and the Si content is 1 wt % or more and 10 wt % or less of the entire magnetic metal phase.

6. A composite magnetic material comprising a plurality of flat magnetic metal particles and an intervening phase, wherein the plurality of flat magnetic metal particles have flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and the average thickness 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 2 or more and 10,000 or less, and the flat surfaces include flat magnetic metal particles having portions curved by 30 degrees or more, and the intervening phase is present between the plurality of flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

7. 7. The composite magnetic material according to claim 6, wherein the average length of said flat surfaces is 100 μm or more and 500 μm or less, the ratio of the maximum length to the minimum length of said flat surfaces is 1.2 or more, and said flat surfaces have sharp contours.

8. 7. The composite magnetic material according to claim 6, wherein the average length of said flat surfaces is 1 μm or more and 200 μm or less, the ratio of the maximum length to the minimum length of said flat surfaces is 1 or more and 2 or less, and the contour is smooth.

9. 7. The composite magnetic material according to claim 6, comprising flat magnetic metal particles having a thickness at the end greater than the thickness at the center.

10. 7. The composite magnetic material according to claim 6, wherein the magnetic metal phase contains Fe and Si, and the Si content is 1 wt % to 10 wt % of the entire magnetic metal phase.

11. 7. The composite magnetic material according to claim 6, wherein the flat magnetic metal particles having the curved portion account for 1% or more of the number of the flat magnetic metal particles.

12. A composite magnetic material as described in claim 6, wherein the flat magnetic metal particles having the curved portions include particles having a maximum angle between adjacent flat magnetic metal particles of 30 degrees or more, and the flat surfaces are aligned in the thickness direction.

13. A magnetic wedge comprising the composite magnetic material of claim 6.

14. A rotating electrical machine comprising the composite magnetic material according to claim 6.

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