Magnetic component and magnetic powder

Abstract

To provide a magnetic component having a high DC overlapping characteristic and a low iron loss.SOLUTION: A magnetic component 500 comprises a magnetic powder 100. The magnetic powder 100 comprises: a metal part 200; an oxide film 300; and at least one specific particle 400. The specific particle 400 has Cu as a main component, and exists in a boundary surface between the metal part 200 and the oxide film 300. The specific particle 400 includes a particle diameter of 3 to 70nm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic component comprising a magnetic powder, and to a magnetic powder used in the magnetic component. [Background technology]

[0002] In Patent Document 1, Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b The soft magnetic powder includes particles having a composition represented by the formula: wherein the particles include crystal grains having a grain size of 1.0 nm to 30.0 nm and a Cu segregation portion in which Cu is segregated, and a dust core including the soft magnetic powder. 100-a-b-c-d M a S b B c Cu d The nanocrystalline soft magnetic alloy is represented by the formula: where at least a part of the alloy has crystal grains with an average grain size of 50 nm or less, and where a Cu segregation portion exists at a depth of more than 2 nm from the surface of the nanocrystalline soft magnetic alloy, and a magnetic core using this nanocrystalline soft magnetic alloy is disclosed. 100-a-b-c-d M a S b B c Cu d The present invention discloses an amorphous alloy ribbon represented by the formula (1) above, in which a Cu segregation portion exists on the surface side of the amorphous alloy ribbon in which Cu is segregated at a higher concentration than in the outermost surface portion, and a magnetic core using a nanocrystalline soft magnetic alloy obtained by nanocrystallizing the amorphous alloy ribbon through heat treatment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-121260 [Patent Document 2] Patent No. 5339192 [Patent Document 3] Patent No. 5429613 Summary of the Invention [Problem to be solved by the invention]

[0004] Magnetic components such as magnetic cores are required to have high DC bias characteristics and low core loss in order to be compact and to handle large currents.

[0005] Therefore, an object of the present invention is to provide a magnetic component that satisfies the above requirements and a magnetic powder that is suitable as a material for such a magnetic component. [Means for solving the problem]

[0006] That is, the present invention provides a first magnetic component, A magnetic component comprising a magnetic powder, The magnetic powder includes a metal portion, an oxide film, and at least one specific particle, the specific particles are mainly composed of Cu and are present at the interface between the metal portion and the oxide film, The specific particles have a particle size of 3 to 70 nm. A magnetic component is provided.

[0007] The present invention also provides a first magnetic powder comprising: A magnetic powder comprising a metal portion, an oxide film, and at least one specific particle, the specific particles are mainly composed of Cu and are present at the interface between the metal portion and the oxide film, The specific particles have a particle size of 3 to 70 nm. A magnetic powder is provided.

[0008] The present invention also provides a first magnetic powder as the second magnetic powder, The concentration of Cu contained in the specific particles is 40 at % or more. A magnetic powder is provided.

[0009] The present invention also provides a third magnetic powder, which is the first magnetic powder, The aspect ratio of the specific particle is greater than 1. A magnetic powder is provided.

[0010] The present invention also provides a fourth magnetic powder, which is the first magnetic powder, The occupancy rate of the specific particles is 4 to 60%. A magnetic powder is provided.

[0011] Further, the present invention provides a fifth magnetic powder, which is any one of the first to fourth magnetic powders, The magnetic powder has the composition formula Fe a S b B c P d Cu e M f It is expressed as M is Cr and / or Nb; 75.4at%≦a≦86.4at%, 0at%≦b≦9at%, 4at%≦c≦13at%, 3at%≦d≦12at%, 0.3at%≦e≦1.0at%, and 0at%≦f≦5at%. A magnetic powder is provided.

[0012] The present invention also provides a sixth magnetic powder, which is the fifth magnetic powder, 3 at % or less of the Fe is substituted with one or more elements selected from Co, Ni, Zn, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Ti, V, Mn, Al, S, C, O, N, Bi and rare earth elements. A magnetic powder is provided. Effect of the Invention

[0013] The magnetic powder of the magnetic component of the present invention has the following characteristics: the magnetic powder comprises a metal part, an oxide film, and at least one specific particle; the specific particle is mainly composed of Cu and exists at the interface between the metal part and the oxide film; the specific particle has a particle size of 3 to 70 nm. As a result, the magnetic component of the present invention has high DC bias characteristics and suppresses iron loss. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing a portion of a magnetic component according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic cross-sectional view showing a part of a magnetic powder used as a material for the magnetic component of FIG. [Diagram 3] 1 is a STEM image showing a part of the magnetic powder of Example 7. In the figure, the locations where area analysis was performed are indicated as P1, P2, P3, and P4, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 1, a magnetic component 500 according to an embodiment of the present invention is a composite magnetic body in which magnetic powder 100 is dispersed within a hardened binder 600. In other words, the magnetic component 500 includes the magnetic powder 100.

[0016] The magnetic powder 100 according to the embodiment of the present invention is an Fe-based soft magnetic alloy powder having Fe as a main element and an amorphous phase as a main phase. The composition of the magnetic powder 100 will be described later. The magnetic powder 100 according to the present embodiment can be used as a direct material for producing various magnetic parts and dust cores.

[0017] Referring to FIG. 2, the magnetic powder 100 of the present embodiment is composed of a plurality of particles 110 having an amorphous phase as a main phase and being substantially spherical. Note that the present invention is not limited thereto, and the particles 110 may have a shape other than substantially spherical. The surface of the particles 110 of the present embodiment is not coated with glass or the like. Note that the present invention is not limited thereto, and the surface of the particles 110 may be coated with glass or the like. In the magnetic powder 100 in which the surface of the particles 110 is coated with glass or the like, the insulation resistance and the flowability are improved compared to the magnetic powder 100 in which the surface of the particles 110 is not coated with glass or the like.

[0018] 2, the particle 110 of the present embodiment includes a metal portion 200, an oxide film 300, and at least one specific particle 400. That is, the magnetic powder 100 of the present embodiment includes a metal portion 200, an oxide film 300, and at least one specific particle 400.

[0019] 2, the metal part 200 of this embodiment is mainly composed of Fe. The metal part 200 has a crystalline phase. More specifically, the metal part 200 has nanocrystals. The nanocrystals are generated by subjecting the magnetic powder 100 to a heat treatment as described below. The metal part 200 is located deeper from the surface of the particle 110 than the oxide film 300.

[0020] 2, the oxide film 300 of this embodiment is a film mainly composed of oxide. That is, the oxide film 300 is mainly composed of O. The proportion of O contained in the oxide film 300 is 35 at % or more. The oxide film 300 is located at a position shallower from the surface of the particle 110 than the metal portion 200. The oxide film 300 forms the surface of the magnetic powder 100.

[0021] Referring to FIG. 2, the specific particle 400 of the present embodiment is mainly composed of Cu. At least one of the specific particles 400 is located at the interface between the metal part 200 and the oxide film 300. In other words, the magnetic powder 100 includes at least one specific particle 400 located at the interface between the metal part 200 and the oxide film 300. In the radial direction of the particle 110, one surface of the specific particle 400 is in contact with the metal part 200, and the other surface of the specific particle 400 is in contact with the oxide film 300. The magnetic powder 100 may be configured such that at least one of the specific particles 400 is located at the interface between the metal part 200 and the oxide film 300, and at least another of the specific particles 400 is located inside the oxide film 300. This is preferable because the magnetic powder 100 is less likely to be magnetically saturated.

[0022] 2, the specific particle 400 of the present embodiment has a particle size of 3 to 70 nm. If the particle size of the specific particle 400 is too small, the magnetic coupling between the particles 110 cannot be suppressed. For this reason, the specific particle 400 preferably has a particle size of 5 nm or more. In addition, since Cu, which is the main component of the specific particle 400, is conductive, if the particle size of the specific particle 400 is too large, an eddy current is likely to flow in the specific particle 400 due to an AC magnetic field, and eddy current loss increases. For this reason, the specific particle 400 preferably has a particle size of 50 nm or less.

[0023] The concentration of Cu contained in the specific particle 400 of the present embodiment is 40 at % or more. In addition, in order to suppress magnetic coupling between the particles 110, the concentration of Cu contained in the specific particle 400 is preferably 60 at % or more.

[0024] 2, the aspect ratio of the specific particle 400 of the present embodiment is greater than 1. Furthermore, when the specific particle 400 has an elliptical cross section, the surface of the particle 110 can be efficiently made nonmagnetic, and therefore the aspect ratio of the specific particle 400 is preferably 1.4 or greater.

[0025] In the magnetic powder 100 of this embodiment, the specific particles 400 exist independently without being directly bound to each other. Note that the present invention is not limited to this, and multiple specific particles 400 may be directly bound to each other to form larger particles. This is preferable because the magnetic powder 100 is less likely to become magnetically saturated.

[0026] 2, the occupancy rate Oc of the specific particles 400 in this embodiment is 4 to 60%. Here, the occupancy rate Oc is a value obtained by the following formula (1) when the length of the interface between the metal part 200 and the oxide film 300 when the particle 110 of the magnetic powder 100 is viewed at a specified cross section is Lb, and the length along the interface between the metal part 200 and the oxide film 300 of each of n specific particles 400 located on the interface between the metal part 200 and the oxide film 300 is Li (i=1 to n). Formula (1): Oc = (ΣLi) / Lb * 100 If the occupancy rate of the specific particles 400 is too small, the magnetic coupling between the particles 110 cannot be suppressed. For this reason, the occupancy rate of the specific particles 400 is preferably 10% or more. In addition, since Cu, which is the main component of the specific particles 400, is conductive, an AC magnetic field may cause eddy currents to flow in the specific particles 400. However, by locating the specific particles 400 at intervals, insulation between the specific particles 400 is ensured, and an increase in eddy current loss can be suppressed. For this reason, the occupancy rate of the specific particles 400 is preferably 50% or less.

[0027] The composition range of the magnetic powder 100 according to this embodiment will be explained in more detail below.

[0028] Referring to FIG. 1, magnetic powder 100 of the present embodiment has the composition formula Fe a S b B c P d Cu e M f The formula is Fe a S b B c P d Cu e M fIn the formula, M is Cr and / or Nb, and 75.4 at%≦a≦86.4 at%, 0 at%≦b≦9 at%, 4 at%≦c≦13 at%, 3 at%≦d≦12 at%, 0.3 at%≦e≦1.0 at%, and 0 at%≦f≦5 at%.

[0029] In the magnetic powder 100 according to the present embodiment, the Fe element is a main element and is an essential element responsible for magnetism. The higher the Fe ratio, the higher the magnetic flux density Bs and the lower the raw material price. In addition, when the Fe ratio is below 75.4 at%, Tx1 (described later) becomes higher and ΔT (described later) becomes smaller. Therefore, it is difficult to heat treat the magnetic powder 100, and the magnetic properties after the heat treatment deteriorate. In addition, when the Fe ratio exceeds 86.4 at%, the amorphousness is significantly reduced and the soft magnetic properties deteriorate. In addition, the crystallinity of the magnetic powder 100 is suppressed to improve the amorphousness, and the soft magnetic properties after the heat treatment of the magnetic powder 100 are improved, so that the Fe ratio is more preferably in the range of 77.9 to 84.9 at%.

[0030] In the magnetic powder 100 according to the present embodiment, the Si element is an element responsible for forming the amorphous phase. When the magnetic powder 100 contains Si, ΔT (described later) becomes large, and the heat treatment can be performed stably. However, if the proportion of Si exceeds 9 at%, the amorphous forming ability decreases, and it becomes impossible to obtain the magnetic powder 100 having an amorphous phase as the main phase, so the proportion of Si is preferably 9 at% or less.

[0031] In the magnetic powder 100 according to the present embodiment, the B element is an essential element responsible for forming an amorphous phase. If the proportion of B is below 4 at%, it becomes difficult to form an amorphous phase by rapid cooling when producing the magnetic powder 100, and good magnetic properties cannot be obtained. If the proportion of B exceeds 13 at%, the melting point becomes high, which is not preferable in terms of production, and the ability to form an amorphous phase also decreases. For this reason, the proportion of B is preferably in the range of 4 to 13 at%.

[0032] In the magnetic powder 100 according to the present embodiment, the P element is an essential element responsible for the formation of the amorphous phase. By containing P in the magnetic powder 100, it becomes easier to form a fine and uniform nanocrystalline structure, and good magnetic properties can be obtained. In addition, P has a high affinity with Cu, and can efficiently form the specific particles 400 near the surface of the particle 110. However, if the proportion of P exceeds 12 at%, the balance with other metalloid elements becomes poor, and the ability to form an amorphous phase decreases. In addition, if the proportion of P exceeds 12 at%, the saturation magnetic flux density Bs decreases significantly. Furthermore, if the proportion of P is less than 3 at%, the crystal grains tend to become large, and good magnetic properties cannot be obtained. For this reason, the proportion of P is preferably in the range of 3 to 12 at%.

[0033] In the magnetic powder 100 according to the present embodiment, the Cu element is an essential element that contributes to the formation of a nanocrystalline phase. If the proportion of Cu is less than 0.3 at%, cluster precipitation during heat treatment is small, making uniform nanocrystallization difficult. If the proportion of Cu exceeds 1.0 at%, the amorphous forming ability decreases, or the occupancy rate of the specific particles 400 becomes too large. For this reason, the proportion of Cu is preferably in the range of 0.3 to 1.0 at%. In particular, in order to improve the amorphous nature of the magnetic powder 100 and enable uniform nanocrystallization, and to make the size and occupancy rate of the specific particles 400 appropriate and to improve the soft magnetic properties after heat treatment, the proportion of Cu is more preferably 0.7 at% or less.

[0034] In the magnetic powder 100 of the present embodiment, the proportion of M is 0 at % or more and 5 at % or less, where M is Cr and / or Nb.

[0035] By containing Cr in the magnetic powder 100 of this embodiment, an oxide film 300 is easily formed on the surface of the particles 110 of the magnetic powder 100, and corrosion resistance is improved. In addition, by containing Nb in the magnetic powder 100 of this embodiment, the growth of bccFe (αFe) crystal grains is suppressed during nanocrystallization, and a fine nanocrystalline structure is easily formed. However, since the content of Cr and Nb relatively reduces the proportion of Fe in the magnetic powder 100, the saturation magnetic flux density Bs of the magnetic powder 100 decreases, and the ability of the magnetic powder 100 to form an amorphous phase also decreases. Therefore, the proportion of M in the magnetic powder 100 needs to be 5 at% or less.

[0036] The magnetic powder 100 according to the present embodiment is preferably one in which 3 at % or less of Fe is replaced with one or more elements selected from Co, Ni, Zn, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Ti, V, Mn, Al, S, C, O, N, Bi, and rare earth elements. This makes it possible to easily precipitate uniform nanocrystals in the magnetic powder 100 when the magnetic powder 100 is heat-treated, and also makes it possible to keep the adverse effects of the above elements in the magnetic powder 100 on the magnetic properties, etc., within an acceptable range.

[0037] The magnetic powder 100, the magnetic component 500 and the manufacturing method thereof according to this embodiment will be described in more detail below.

[0038] The magnetic powder 100 of the present embodiment can be produced by an atomization method such as a water atomization method or a gas atomization method. The magnetic powder 100 produced in this manner has a non-crystalline phase (amorphous phase) as a main phase and is composed of a plurality of particles 110 that are substantially spherical. The present invention is not limited to this, and the magnetic powder 100 may be composed of flakes formed by pulverizing an amorphous ribbon. That is, the particles 110 constituting the magnetic powder 100 of the present invention may not be substantially spherical. Even if the magnetic powder 100 is thus formed by pulverizing an amorphous ribbon, it can have a high saturation magnetic flux density Bs and a high relative permeability μ by having the configuration of the present invention.

[0039] In the powder production process using the atomization method, first, raw materials are prepared. Next, the raw materials are weighed to obtain a predetermined composition and melted to produce a molten alloy. At this time, since the magnetic powder 100 of this embodiment has a low melting point, the power consumption for melting can be reduced. Next, the molten alloy is discharged from a nozzle and is divided into alloy droplets using high-pressure gas or water, thereby producing fine magnetic powder 100.

[0040] In the above-mentioned powder production process, the gas used for the division may be an inert gas such as argon or nitrogen. In addition, in order to improve the cooling rate, the alloy droplets immediately after division may be rapidly cooled by contacting them with a cooling liquid or solid, or the alloy droplets may be further divided into smaller droplets by re-dividing them. When a liquid is used for cooling, for example, water or oil may be used. When a solid is used for cooling, for example, a rotating copper roll or a rotating aluminum plate may be used. However, the liquid or solid for cooling is not limited to these, and various materials may be used.

[0041] Here, the quenching rate by the atomization method is 10 3 K / s or more. The quenching rate is 10 3 If the quenching rate is less than 10 K / s, the amount of precipitated initial crystals (mainly bccFe) increases, and accordingly, the amount of Cu precipitated in the metal part 200 increases. 3 If the quenching rate is less than 10 K / s, the composition of the amorphous phase in the magnetic powder 100 will deviate from the desired composition, and the glass transition temperature Tg will not appear. 3 If the cooling rate is less than 10 K / s, the first crystallization start temperature Tx1 will shift to the higher temperature side, or the temperature peak due to the first crystallization will decrease. 4 K / s or higher is preferred.

[0042] The magnetic powder 100 of the present invention preferably contains nanocrystals. Here, the magnetic powder 100 containing nanocrystals is obtained by subjecting the magnetic powder 100 to a heat treatment under predetermined heat treatment conditions to precipitate nanocrystals of bccFe (αFe), as described below.

[0043] When the magnetic powder 100 is heat-treated in a low-oxygen atmosphere mainly composed of an inert gas such as argon, it is crystallized two or more times. The temperature at which the first crystallization starts is called the first crystallization onset temperature (Tx1), and the temperature at which the second crystallization starts is called the second crystallization onset temperature (Tx2). The temperature difference between the first crystallization onset temperature (Tx1) and the second crystallization onset temperature (Tx2) is called ΔT=Tx2-Tx1. The first crystallization onset temperature (Tx1) is the exothermic peak of the precipitation of nanocrystals of αFe, and the second crystallization onset temperature (Tx2) is the exothermic peak of the precipitation of compounds such as FeB and FeP. These crystallization onset temperatures can be evaluated, for example, by performing a thermal analysis at a heating rate of about 10°C / min using a differential scanning calorimetry (DSC) device.

[0044] In order to precipitate nanocrystals of αFe in the magnetic powder 100, it is desirable to perform heat treatment at a temperature equal to or lower than the second crystallization onset temperature (Tx2) so as to suppress the precipitation of the compound phase. Here, when ΔT is large, heat treatment under a specified heat treatment condition becomes easy. Therefore, it is possible to obtain magnetic powder 100 with good soft magnetic properties by precipitating only nanocrystals of αFe by heat treatment. That is, by adjusting the elemental composition of magnetic powder 100 so as to increase ΔT and performing heat treatment, the nanocrystal structure of αFe contained in magnetic powder 100 becomes stable, and the iron loss of magnetic component 500 including magnetic powder 100 containing nanocrystals of αFe is also reduced.

[0045] In order to produce the magnetic powder 100 containing nanocrystals, the magnetic powder 100 produced by the above-mentioned powder production process is heat-treated as described above to precipitate αFe nanocrystals in the magnetic powder 100. As described above, this heat treatment needs to be performed at a temperature equal to or lower than the second crystallization onset temperature (Tx2) so as not to precipitate a compound phase. In addition, this heat treatment is preferably performed at a temperature of 300° C. or higher in a low-oxygen atmosphere mainly composed of an inert gas such as nitrogen or argon in order to form an oxide film 300 on the surface of the particles 110 of the magnetic powder 100.

[0046] The magnetic powder 100 produced by the above-mentioned powder production process can be used to produce a magnetic component 500. For example, the magnetic powder 100 can be molded into a predetermined shape and then heat-treated under predetermined heat treatment conditions to produce the magnetic component 500. In addition, the magnetic component 500 can be used to produce magnetic components such as transformers, inductors, motors, and generators. A method for producing the magnetic component 500 of this embodiment using the magnetic powder 100 will be described below.

[0047] The manufacturing method of the magnetic component 500 of the present embodiment includes a step of producing a mixture of the magnetic powder 100 of the present embodiment and the binder 600, a step of pressure-molding this mixture to produce a molded body, and a step of heat-treating the molded body.

[0048] First, in the process of producing a mixture of the magnetic powder 100 and the binder 600, the magnetic powder 100 of the present embodiment is mixed with the binder 600 having good insulating properties such as resin to obtain a mixture (granulated powder). When a resin is used as the binder 600, for example, silicone, epoxy, phenol, melamine, polyurethane, polyimide, or polyamideimide may be used. In order to improve insulating properties and binding properties, materials such as phosphates, borates, chromates, oxides (silica, alumina, magnesia, etc.), and inorganic polymers (polysilane, polygermane, polystannane, polysiloxane, polysilsesquioxane, polysilazane, polyborazylene, polyphosphazene, etc.) may be used as the binder 600 instead of or together with the resin. In addition, a plurality of binders 600 may be used in combination, and a coating having a multi-layer structure of two or more layers may be formed by using different binders 600. In addition, since the manufacturing of the magnetic component 500 includes a process of heat-treating the molded body as described above, it is preferable to use a binder 600 having high heat resistance. The amount of binder 600 is generally preferably about 0.1 to 10 wt%, and is preferably about 0.3 to 6 wt% in consideration of insulation and filling rate. However, the amount of binder 600 may be appropriately determined in consideration of the powder particle size, applied frequency, application, etc.

[0049] Next, in the process of producing a molded body by pressure molding the mixture, the granulated powder is pressure molded using a mold to obtain a molded body. When the granulated powder is pressure molded, in order to improve the filling property and suppress the heat generation in nanocrystallization, a powder such as Fe, FeSi, FeSiCr, FeSiAl, FeNi, or carbonyl iron powder that is softer than the magnetic powder 100 according to the present embodiment may be mixed. In addition, instead of the above soft powder, or together with the above soft powder, any magnetic powder 100 having a particle size different from that of the magnetic powder 100 according to the present embodiment may be mixed. At this time, the amount of the mixture relative to the magnetic powder 100 according to the present embodiment is preferably 50 wt% or less.

[0050] The molded body is then subjected to a heat treatment under predetermined heat treatment conditions. This heat treatment causes αFe nanocrystals to precipitate in the magnetic powder 100. This heat treatment is similar to the heat treatment for the magnetic powder 100 described above, and must be performed at a temperature equal to or lower than the second crystallization onset temperature (Tx2). In addition, this heat treatment is preferably performed at a temperature of 300° C. or higher in a low-oxygen atmosphere mainly composed of an inert gas such as nitrogen or argon, in order to form an oxide film 300 on the surface of the particles 110 of the magnetic powder 100.

[0051] The magnetic component 500 in this embodiment is manufactured using the magnetic powder 100 that has not been heat-treated as a raw material, but the present invention is not limited to this, and the magnetic component 500 may be manufactured using the magnetic powder 100 that has been heat-treated in advance to precipitate αFe nanocrystals as a raw material. In this case, the magnetic component 500 can be manufactured by carrying out granulation and pressure molding in the same manner as in the manufacturing process of the magnetic component 500 described above.

[0052] The magnetic powder 100 of the present embodiment is used in the magnetic component 500 of the present embodiment produced as described above, regardless of the production process. Similarly, the magnetic powder 100 of the present embodiment is used in the magnetic component 500 of the present embodiment.

[0053] Hereinafter, the embodiment of the present invention will be described in more detail with reference to several examples.

[0054] (Examples 1 to 39 and Comparative Examples 1 to 10) As raw materials for the magnetic powders 100 of Examples 1 to 15, 24 to 28 and Comparative Examples 1 to 5 and 10 shown in Table 2 below, industrially pure iron, ferrosilicon, ferrophosphorus, ferroboron, ferrochrome, and electrolytic copper were prepared. The raw materials were weighed to obtain the alloy compositions of Examples 1 to 39 and Comparative Examples 1 to 10, and melted by high-frequency melting in an argon atmosphere to prepare molten alloys. Next, the prepared molten alloys were quenched by water atomization to prepare magnetic powders 100 with an average particle size of 3 to 15 μm. Similarly to the above, magnetic powders 100 with an average particle size of 15 to 65 μm were prepared for the magnetic powders 100 of Examples 16 to 23, 29 to 39 and Comparative Examples 6 to 9 shown in Table 2 below.

[0055] The magnetic powder 100 of Example 7 thus produced was subjected to heat treatment in an electric furnace in a low-oxygen atmosphere mainly composed of an inert gas at a predetermined temperature between 375°C and 475°C for a predetermined time. In this heat treatment, the oxygen concentration in the treatment atmosphere was set to be in the range of 5 to 10,000 ppm, and the oxygen concentration at the start of the temperature rise was set to be higher than the oxygen concentration after a predetermined time had elapsed. In addition, this heat treatment nano-crystallizes the magnetic powder 100.

[0056] A thin film sample was prepared from the magnetic powder 100 of Example 7 after the heat treatment by the FIB (focused ion beam) method, and the prepared thin film sample was observed with a scanning transmission electron microscope (STEM), and element mapping analysis and area analysis were performed by energy dispersive X-ray spectroscopy (STEM-EDS). The results of the STEM observation and element mapping analysis are shown in Figure 3. The points (P1, P2, P3, P4) where the area analysis was performed are shown in Figure 3, and the element analysis results of each point are shown in Table 1.

[0057] [Table 1]

[0058] From FIG. 3, it was confirmed that the magnetic powder 100 of Example 7 has a plurality of specific particles 400 mainly composed of Cu. Also, from FIG. 3 and Table 1, it was confirmed that the P1 portion of the magnetic powder 100 of Example 7 contains Cu at a high concentration of 69.2 at%. It was also confirmed that the particle size of the particle at the P1 portion is about 16 nm. Furthermore, it was confirmed that the P2 and P3 portions of the magnetic powder 100 of Example 7 contain O at high concentrations of 67.9 at% and 60.1 at%, respectively, while there is almost no Cu. In addition, it was confirmed that the P4 portion of the magnetic powder 100 of Example 7 contains Fe at a high concentration of 80.6 at%, while there is almost no Cu. From these results, it was confirmed that the magnetic powder 100 of Example 7 comprises a metal part 200 mainly composed of Fe, an oxide film 300 mainly composed of O, and a plurality of specific particles 400 mainly composed of Cu, the specific particles 400 being present at the interface between the metal part 200 and the oxide film 300, and the particle size of the specific particles 400 being in the range of 3 to 70 nm.

[0059] Using the magnetic powders 100 before heat treatment according to Examples 1 to 39 produced by the above method, magnetic components (dust cores) 500 according to Examples 1 to 39 were produced by the following method.

[0060] First, the magnetic powder 100 of Examples 1 to 39 and the binder (silicone resin) 600 manufactured are mixed so that the ratio of the binder 600 to the magnetic powder 100 is 3 wt%, and the mixture is sized using a stainless steel sieve with a mesh size of 500 μm to obtain granules. Then, the granules are filled into a mold, and the granules filled in the mold are molded with a hydraulic press at a molding pressure of 490 MPa. This produces a cylindrical molded body with an outer diameter of 13 mm and an inner diameter of 8 mm. Then, the molded body manufactured is heated to a predetermined temperature between 375 ° C. and 475 ° C. at a heating rate of 30 ° C. / min in a low-oxygen atmosphere mainly composed of an inert gas using an infrared heating device, and then the predetermined temperature is maintained for 20 minutes, and then air-cooled to room temperature to produce the magnetic parts (dust cores) 500 of Examples 1 to 39. In this heat treatment, the oxygen concentration in the treatment atmosphere was set to be in the range of 5 to 10,000 ppm, and the oxygen concentration at the start of the temperature rise was set to be higher than the oxygen concentration immediately before air cooling. This heat treatment also hardens the silicone resin that is the binder 600 and nano-crystallizes the magnetic powder 100.

[0061] Further, magnetic components (dust cores) according to Comparative Examples 1 to 10 were produced using the powders of Comparative Examples 1 to 10 in a manner similar to that described above.

[0062] The fabricated dust cores 500 of Examples 1 to 39 were cut, then processed with a cross section polisher (CP), and thin film samples were fabricated by a focused ion beam (FIB) method. The fabricated thin film samples were observed with a TEM to obtain multiple TEM images, and elemental analysis was performed with an EDX attached to the TEM. Based on these observation and analysis results, the particle size, aspect ratio, and concentration of the specific particles 400 in the magnetic powder 100 constituting the fabricated dust cores 500 of Examples 1 to 39 were derived. Further, based on each of the obtained TEM images, the length Lb of the interface between the metal part 200 and the oxide film 300 and the length Li (i = 1 to n) along the interface between the metal part 200 and the oxide film 300 of each of the n specific particles 400 located on the interface between the metal part 200 and the oxide film 300 were derived, and the occupancy Oc was calculated by the above formula (1), and the average value of the obtained occupancy Oc was taken as the occupancy Oc of the dust core 500 of Examples 1 to 39. In addition, the particle size, aspect ratio, and concentration of the specific particles in the powder constituting the dust cores according to Comparative Examples 1 to 10 were derived by the same method as above, and the occupancy Oc was calculated. These results are shown in Table 2.

[0063] [Table 2]

[0064] From Table 2, it can be seen that in the powder magnetic cores 500 of Examples 1 to 28, the particle size of the specific particles 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particles 400 is 40 at% or more, the aspect ratio of the specific particles 400 is greater than 1, and the occupancy rate of the specific particles 400 is in the range of 4 to 60%.

[0065] Furthermore, from Table 2, it can be seen that while the magnetic powders 100 of Examples 29 and 30 have 3 at% or less of Fe replaced with C, in the powder magnetic cores 500 of Examples 29 and 30, the particle size of the specific particles 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particles 400 is 40 at% or more, the aspect ratio of the specific particles 400 is greater than 1, and the occupancy rate of the specific particles 400 is in the range of 4 to 60%.

[0066] Furthermore, from Table 2, it can be seen that while the magnetic powder 100 of Example 31 has 3 at% or less of Fe replaced with Co, in the powder magnetic core 500 of Example 31, the particle size of the specific particle 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particle 400 is 40 at% or more, the aspect ratio of the specific particle 400 is greater than 1, and the occupancy rate of the specific particle 400 is in the range of 4 to 60%.

[0067] In addition, Table 2 shows that while the magnetic powder 100 of Example 32 has 3 at% or less of Fe replaced with Zn, in the powder core 500 of Example 32, the particle size of the specific particle 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particle 400 is 40 at% or more, the aspect ratio of the specific particle 400 is greater than 1, and the occupancy rate of the specific particle 400 is in the range of 4 to 60%.

[0068] In addition, Table 2 shows that the magnetic powders 100 of Examples 33 and 34 have 3 at% or less of Fe replaced with Sn, while the powder cores 500 of Examples 33 and 34 have specific particles 400 mainly composed of Cu, with a particle size in the range of 3 to 70 nm, a concentration of Cu contained in the specific particles 400 of 40 at% or more, an aspect ratio of the specific particles 400 greater than 1, and an occupancy rate of the specific particles 400 in the range of 4 to 60%.

[0069] In addition, Table 2 shows that while the magnetic powder 100 of Example 35 has 3 at% or less of Fe replaced with Ni, in the powder core 500 of Example 35, the particle size of the specific particle 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particle 400 is 40 at% or more, the aspect ratio of the specific particle 400 is greater than 1, and the occupancy rate of the specific particle 400 is in the range of 4 to 60%.

[0070] In addition, Table 2 shows that while the magnetic powder 100 of Example 36 has 3 at% or less of Fe replaced with Mn, in the powder core 500 of Example 36, the particle size of the specific particles 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particles 400 is 40 at% or more, the aspect ratio of the specific particles 400 is greater than 1, and the occupancy rate of the specific particles 400 is in the range of 4 to 60%.

[0071] In addition, Table 2 shows that while the magnetic powder 100 of Example 37 has 3 at% or less of Fe replaced with Al, in the powder core 500 of Example 37, the particle size of the specific particles 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particles 400 is 40 at% or more, the aspect ratio of the specific particles 400 is greater than 1, and the occupancy rate of the specific particles 400 is in the range of 4 to 60%.

[0072] In addition, Table 2 shows that while the magnetic powder 100 of Example 38 has 3 at% or less of Fe replaced with Ti, in the powder core 500 of Example 38, the particle size of the specific particles 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particles 400 is 40 at% or more, the aspect ratio of the specific particles 400 is greater than 1, and the occupancy rate of the specific particles 400 is in the range of 4 to 60%.

[0073] In addition, Table 2 shows that while the magnetic powder 100 of Example 39 has 3 at% or less of Fe replaced with O, in the powder core 500 of Example 39, the particle size of the specific particles 400 mainly composed of Cu is in the range of 3 to 70 nm, the concentration of Cu contained in the specific particles 400 is 40 at% or more, the aspect ratio of the specific particles 400 is greater than 1, and the occupancy rate of the specific particles 400 is in the range of 4 to 60%.

[0074] On the other hand, from Table 2, it can be seen that the powder of Comparative Example 1 has an Fe content of less than 75.4 at% and the powder of Comparative Example 2 has an Fe content of more than 86.4 at%. However, in the powder magnetic cores of Comparative Examples 1 and 2, the particle size of the specific particles is less than 3 nm, the Cu concentration in the specific particles is less than 40 at%, and the occupancy rate of the specific particles is not within the range of 4 to 60%.

[0075] Furthermore, from Table 2, it can be seen that while the powder of Comparative Example 3 contains more than 9 at% Si, in the powder magnetic core of Comparative Example 3, the particle size of the specific particles is less than 3 nm, the Cu concentration in the specific particles is less than 40 at%, and the occupancy rate of the specific particles is not within the range of 4 to 60%.

[0076] Furthermore, from Table 2, it can be seen that the powder of Comparative Example 4 has a B content of less than 4 at% and the powder of Comparative Example 5 has a B content of more than 13 at%. However, in the powder magnetic cores of Comparative Examples 4 and 5, the particle size of the specific particles is less than 3 nm, the Cu concentration in the specific particles is less than 40 at%, and the occupancy rate of the specific particles is not within the range of 4 to 60%.

[0077] Furthermore, from Table 2, it can be seen that the powder of Comparative Example 6 has a P content of less than 3 at% and the powder of Comparative Example 7 has a P content of more than 12 at%. However, in the powder core of Comparative Example 6, the particle size of the specific particles is less than 3 nm and the Cu concentration in the specific particles is less than 40 at%, so the occupancy rate of the specific particles is not within the range of 4 to 60%, and in the powder core of Comparative Example 7, the particle size of the specific particles exceeds 70 nm and the occupancy rate of the specific particles is not within the range of 4 to 60%.

[0078] Furthermore, from Table 2, it can be seen that the powder of Comparative Example 8 has a Cu content of less than 0.3 at% and the powder of Comparative Example 9 has a Cu content of more than 1.0 at%; however, in the powder core of Comparative Example 8, the particle size of the specific particles is less than 3 nm, the Cu concentration in the specific particles is less than 40 at%, and the occupancy rate of the specific particles is not within the range of 4 to 60%, and in the powder core of Comparative Example 9, the particle size of the specific particles exceeds 70 nm, and the occupancy rate of the specific particles is not within the range of 4 to 60%.

[0079] Furthermore, from Table 2, it can be seen that while the powder of Comparative Example 10 has an M value exceeding 5 at%, in the powder magnetic core of Comparative Example 10, the particle size of the specific particles is less than 3 nm, the Cu concentration in the specific particles is less than 40 at%, and the occupancy rate of the specific particles is not within the range of 4 to 60%.

[0080] For the produced powder cores 500 of Examples 1 to 15, 24 to 28 and the powder cores of Comparative Examples 1 to 5 and 10, the DC bias characteristics at 100 kHz were measured using an LCR meter connected to a dedicated DC bias power supply, and the retention ratio R (%) was calculated. Here, the retention ratio R is a value calculated by the following formula (2), where the measured value of L (or μ) at 0 kA / m is L0 (or μ0) and the measured value of L (or μ) at 8 kA / m is Lx (or μx). Formula (2): R = Lx (or μx) / L0 (or μ0) * 100 In addition, for the powder magnetic cores 500 produced in Examples 1 to 15, 24 to 28 and the powder magnetic cores in Comparative Examples 1 to 5 and 10, the iron loss Pcv (kW / m 3 The results are shown in Table 3.

[0081] [Table 3]

[0082] As can be seen from Table 3, in the powder magnetic cores 500 of Examples 1 to 15 and 24 to 28, the retention rate R was 70% or more, and the iron loss Pcv was 1250 kW / m 3 It can be seen that the following is true.

[0083] On the other hand, as can be seen from Table 3, in the powder cores of Comparative Examples 1 and 2 in which Fe was not within the range of 75.4 to 86.4 at%, the powder core of Comparative Example 3 in which Si exceeded 9 at%, the powder core of Comparative Example 4 in which B was less than 4 at%, the powder core of Comparative Example 5 in which B exceeded 13 at%, and the powder core of Comparative Example 10 in which M exceeded 5 at%, the retention rate R was less than 70% and the iron loss Pcv was 1250 kW / m 3 It is clear that this exceeds

[0084] These findings show that the dust cores 500 of Examples 1 to 15 and 24 to 28 have improved DC bias characteristics and reduced iron loss compared to the dust cores of Comparative Examples 1 to 5 and 10.

[0085] For the produced powder cores 500 of Examples 16 to 23, 29 to 39 and the powder cores of Comparative Examples 6 to 9, the DC bias characteristics at 100 kHz were measured using an LCR meter connected to a dedicated DC bias power supply, and the retention ratio R (%) was calculated using the above formula (2). In addition, for the produced powder cores 500 of Examples 16 to 23, 29 to 39 and the powder cores of Comparative Examples 6 to 9, the iron loss Pcv (kW / m 3 The results are shown in Table 4.

[0086] [Table 4]

[0087] From Table 4, in the powder magnetic cores 500 of Examples 16 to 23 and 29 to 39, the retention rate R was 70% or more, and the iron loss Pcv was 300 kW / m 3 It can be seen that the following is true.

[0088] On the other hand, as can be seen from Table 4, in the powder magnetic core of Comparative Example 6 in which P is less than 3 at %, and in the powder magnetic core of Comparative Example 8 in which Cu is less than 0.3 at %, the retention rate R is less than 70%, and the iron loss Pcv is 300 kW / m 3 It can also be seen from Table 4 that the iron loss Pcv exceeds 300 kW / m in the powder magnetic core of Comparative Example 7 in which P exceeds 12 at % and the powder magnetic core of Comparative Example 9 in which Cu exceeds 1.0 at %. 3 It is clear that this far exceeds

[0089] These findings show that the dust cores 500 of Examples 16-23 and 29-39 have improved DC bias characteristics and reduced iron loss compared to the dust cores of Comparative Examples 6-9.

[0090] Although the best mode for carrying out the present invention has been described, it will be apparent to those skilled in the art that modifications can be made to the present invention without departing from the spirit of the present invention, and such modifications are within the scope of the present invention. [Explanation of symbols]

[0091] 100 magnetic powder 110 particles 200 Metal Parts 300 Oxide film 400 specific particles 500 Magnetic parts (powder cores) 600 Binder Lb Length Li Length

Claims

1. A magnetic component comprising a magnetic powder, The magnetic powder includes a metal portion, an oxide film, and at least one specific particle, the specific particles are mainly composed of Cu and are present at the interface between the metal portion and the oxide film, The specific particles have a particle size of 3 to 70 nm. Magnetic parts.

2. A magnetic powder comprising a metal portion, an oxide film, and at least one specific particle, the specific particles are mainly composed of Cu and are present at the interface between the metal portion and the oxide film, The specific particles have a particle size of 3 to 70 nm. magnetic powder.

3. The magnetic powder according to claim 2, The concentration of Cu contained in the specific particles is 40 at % or more. magnetic powder.

4. The magnetic powder according to claim 2, The aspect ratio of the specific particle is greater than 1. magnetic powder.

5. The magnetic powder according to claim 2, The occupancy rate of the specific particles is 4 to 60%. magnetic powder.

6. A magnetic powder according to any one of claims 2 to 5, The magnetic powder has the composition formula Fe, excluding inevitable impurities. ａ S ｂ B ｃ P ｄ Cu ｅ M ｆ It is expressed as M is Cr and / or Nb; 75.4 at%≦a≦86.4 at%, 0 at%≦b≦9 at%, 4 at%≦c≦13 at%, 3 at%≦d≦12 at%, 0.3 at%≦e≦1.0 at%, and 0 at%≦f≦5 at%. magnetic powder.

7. The magnetic powder according to claim 6, 3 at % or less of the Fe is substituted with one or more elements selected from Co, Ni, Zn, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Ti, V, Mn, Al, S, C, O, N, Bi and rare earth elements. magnetic powder.

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