JP2017108098A - Dust core, method of producing dust core, inductor including dust core, and electronic/electrical apparatus mounting inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust core containing a powder of crystalline magnetic material and a powder of amorphous magnetic material, and an inductor including such a dust core, where DC superposition characteristics are improved while reducing iron loss.SOLUTION: In a dust core 1 containing a powder of crystalline magnetic material and a powder of amorphous magnetic material, the median size DA of the powder of amorphous magnetic material is 15 μm or less, and the ratio to the median size DC of the powder of crystalline magnetic material satisfies the following formula (1); 1≤DA/DC≤3.5 (1).SELECTED DRAWING: Figure 41

Description

  The present invention relates to a dust core, a method for manufacturing the dust core, an inductor including the dust core, and an electronic / electrical device on which the inductor is mounted. In this specification, the “inductor” is a passive element including a core material including a dust core and a coil, and includes the concept of a reactor.

  A dust core used in a booster circuit such as a hybrid vehicle, a reactor used in power generation or substation equipment, an inductor such as a transformer or a choke coil can be obtained by compacting soft magnetic powder. An inductor including such a dust core is required to have both a low iron loss and an excellent direct current superposition characteristic.

  Patent Document 1 discloses a core formed by pressurizing a mixed powder in which a magnetic powder and a binder are mixed as a means for solving the above-described problem (combining low iron loss and excellent DC superimposition characteristics). There is disclosed an inductor in which a coil in which 5 to 20 wt% of a sendust powder is mixed with a carbonyl iron powder is used as the magnetic powder.

  In Patent Document 2, as an inductor capable of further reducing iron loss, a mixed powder composed of a blending ratio of 90 to 98 mass% amorphous soft magnetic powder and 2 to 10 mass% crystalline soft magnetic powder, and an insulating material are disclosed. An inductor including a magnetic core (a dust core) including a solidified mixture of the above is disclosed. In such a magnetic core (powder core), amorphous soft magnetic powder is a material for reducing the core loss of the inductor, and crystalline soft magnetic powder improves the filling rate of the mixed powder and increases the magnetic permeability. It is positioned as a material that plays the role of a binder for bonding amorphous soft magnetic powders together.

JP 2006-13066 A JP 2010-118486 A

  Patent Document 1 aims to improve DC superposition characteristics by using powders of different types of crystalline magnetic materials as a raw material for the powder core, and Patent Document 2 aims to further reduce iron loss. The powder of the material and the powder of the amorphous magnetic material are used as the raw material for the powder core. However, Patent Document 2 does not evaluate DC superimposition characteristics.

  Accordingly, the present invention provides a dust core containing a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, and improves the direct current superposition characteristics and iron loss of an inductor provided with such a dust core. An object is to provide a powder core that can be reduced. Another object of the present invention is to provide a method for manufacturing the above dust core, an inductor including the dust core, and an electronic / electrical device on which the inductor is mounted.

  As a result of investigations by the present inventors to solve the above-mentioned problems, the particle size distribution of the crystalline magnetic material powder and the particle size distribution of the amorphous magnetic material powder contained in the dust core are appropriately adjusted. Thus, it is possible to improve the DC superposition characteristics of an inductor including a dust core and reduce iron loss. In a preferred embodiment, the powder of crystalline magnetic material contained in the dust core and amorphous magnetic New knowledge that it is possible to improve the DC superposition characteristics of inductors with a dust core and reduce iron loss in a non-linear manner beyond the range estimated from the mixing ratio with the powder of the material Got.

The invention completed by such knowledge is as follows.
One aspect of the present invention is a powder core containing a crystalline magnetic material powder and an amorphous magnetic material powder, wherein the median diameter D ₅₀ A of the amorphous magnetic material powder is 15 μm or less. A powder core characterized by satisfying the median diameter D ₅₀ C of the crystalline magnetic material powder and the following formula (1).
1 ≦ D ₅₀ A / D ₅₀ C ≦ 3.5 (1)

  When the particle size distribution of the crystalline magnetic material powder contained in the dust core and the particle size distribution of the amorphous magnetic material powder satisfy the above relationship, the powder of the crystalline magnetic material contained in the dust core It is possible to improve the DC superposition characteristics of an inductor having a dust core and reduce iron loss in a non-linear manner beyond the range estimated from the mixing ratio of the powder of the amorphous magnetic material and the amorphous magnetic material. .

The median diameter D ₅₀ A of the amorphous magnetic material powder may preferably satisfy the following formula (2) with the median diameter D ₅₀ C of the crystalline magnetic material powder. As shown in the examples described later, when the following formula (2) is satisfied, both of the two parameters (μ0 × μ5500 × Isat / ρ and μ0 × Isat / ρ) indicating the direct current superposition characteristics are likely to be favorable.
1.2 ≦ D ₅₀ A / D ₅₀ C ≦ 2.5 (2)

When the median diameter D ₅₀ A of the powder of the amorphous magnetic material is 7 μm or less, it is possible to more stably realize improvement of DC superposition characteristics and reduction of iron loss of an inductor including a dust core. It may be preferable from the viewpoint.

  The first mixing which is a mass ratio of the content of the crystalline magnetic material powder to the sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder contained in the dust core A ratio of 40% by mass or less may be preferable from the viewpoint of more stably realizing the iron loss of the inductor as compared with an inductor having a dust core made of only amorphous magnetic material powder. is there.

  The first mixing ratio may be 2% by mass or more.

  The crystalline magnetic material is Fe-Si-Cr alloy, Fe-Ni alloy, Fe-Co alloy, Fe-V alloy, Fe-Al alloy, Fe-Si alloy, Fe-Si-Al. One type or two or more types of materials selected from the group consisting of a system alloy, carbonyl iron and pure iron may be included.

  The crystalline magnetic material is preferably made of an Fe—Si—Cr alloy.

  The amorphous magnetic material includes one or more materials selected from the group consisting of Fe-Si-B alloys, Fe-PC-C alloys, and Co-Fe-Si-B alloys. You may go out.

  The amorphous magnetic material is preferably made of a Fe—PC alloy.

  The powder of the crystalline magnetic material is preferably made of an insulating material. By performing the insulation treatment, the insulation resistance of the dust core can be improved and the iron loss in the high frequency band can be more stably realized.

  The dust core contains a binding component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to another material contained in the dust core. Also good. In this case, the binding component preferably includes a component based on a resin material.

  Another aspect of the present invention is the above-described method for producing a dust core, wherein the addition of a mixture comprising the crystalline magnetic material powder, the amorphous magnetic material powder, and the binder component comprising the resin material is performed. A method for producing a powder core, comprising a molding step of obtaining a molded product by a molding process including pressure molding. By such a manufacturing method, it is possible to more efficiently manufacture the powder core.

  In the above manufacturing method, the molded product obtained by the molding step may be the powder core. Or you may provide the heat processing process which obtains the said powder core by the heat processing which heats the said molded product obtained by the said shaping | molding process.

  Still another aspect of the present invention is an inductor including the dust core, the coil, and a connection terminal connected to each end of the coil, wherein at least a part of the dust core is the connection. It is an inductor disposed so as to be located in an induced magnetic field generated by the current when a current is passed through the coil via a terminal. Such an inductor can achieve both excellent direct current superposition characteristics and low loss based on the excellent characteristics of the dust core.

  Still another embodiment of the present invention is an electronic / electrical device in which the inductor is mounted, and the inductor is an electronic / electrical device connected to a substrate by the connection terminal. Examples of such electronic / electrical equipment include a power supply device including a power supply switching circuit, a voltage raising / lowering circuit, and a smoothing circuit, and a small portable communication device. Since the electronic / electrical equipment according to the present invention includes the above-described inductor, it can easily cope with a large current and a high frequency.

  In the dust core according to the above invention, the particle size distribution of the crystalline magnetic material powder and the particle size distribution of the amorphous magnetic material powder are appropriately adjusted. It is possible to improve the direct current superimposition characteristics and reduce iron loss. Moreover, according to this invention, the manufacturing method of said powder core, the inductor provided with the said powder core, and the electronic / electrical device by which the said inductor was mounted are provided.

It is a perspective view which shows notionally the shape of the powder core which concerns on one Embodiment of this invention. It is a figure which shows notionally the spray dryer apparatus used in an example of the method of manufacturing granulated powder, and its operation | movement. It is a perspective view which shows notionally the shape of the toroidal coil which is 1 type of an inductor provided with the dust core which concerns on one Embodiment of this invention. It is a perspective view which shows notionally the shape of the coil embedding type | mold inductor which is a kind of inductor provided with the powder core which concerns on one Embodiment of this invention. 4 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 1. FIG. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 2. FIG. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 3. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 4. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 5. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 6. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 7. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 8. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 9. It is the graph which showed the dependence with respect to the 1st mixing ratio of Relative Pcv in Example 10. 6 is a graph showing the dependency of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 1. FIG. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 2. FIG. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 3. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 4. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 5. FIG. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 6. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 7. FIG. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 8. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 9. 10 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 10. 4 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 1. FIG. 6 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 2. FIG. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 3. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 4. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 5. FIG. 14 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 6. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 7. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 8. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 9. 10 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 10. It is a graph which shows the result of having plotted the relationship between iron loss Pcv and (mu) 0 * (mu) 5500 * Isat / (rho) about the result of Example 1. FIG. It is a graph which shows the result of having plotted the relationship between iron loss Pcv and (mu) 0 * Isat / (rho) about the result of Example 1. FIG. From the viewpoint of comparing the results of Example 1 to Example 8 and Example 10, the case where the first mixing ratio in each example is 30% by mass is picked up, and iron loss Pcv and μ0 × μ5500 × Isat / ρ It is a graph which shows the result of having plotted the relationship. From the viewpoint of comparing the results of Example 1 to Example 8 and Example 10, the case where the first mixing ratio in each Example is 30% by mass is picked up, and the relationship between iron loss Pcv and μ0 × Isat / ρ It is a graph which shows the result of having plotted. It is a graph which shows the result of having plotted the relationship between the iron loss Pcv and μ0 × μ5500 × Isat / ρ for the result of Example 10. It is a graph which shows the result of having plotted the relationship between iron loss Pcv and (mu) 0 * Isat / (rho) about the result of Example 10. FIG. FIG. ₅ is a graph showing the relationship between μ0 × μ5500 × Isat / ρ and D ₅₀ A / D ₅₀ C, and the relationship between μ0 × Isat / ρ and D ₅₀ A / D ₅₀ C, created based on the results of Example 11. is there.

Hereinafter, embodiments of the present invention will be described in detail.
1. A dust core 1 according to one embodiment of the present invention shown in FIG. 1 is a ring-shaped toroidal core, and contains a powder of a crystalline magnetic material and a powder of an amorphous magnetic material. . The powder core 1 according to the present embodiment is manufactured by a manufacturing method including a forming process including pressure forming a mixture containing these powders. As a non-limiting example, the dust core 1 according to the present embodiment includes a crystalline magnetic material powder and an amorphous magnetic material powder as other materials (same type of material) contained in the dust core 1. Or it may be a dissimilar material).

(1) Powder of crystalline magnetic material The crystalline magnetic material that gives the powder of crystalline magnetic material contained in the dust core 1 according to one embodiment of the present invention is crystalline (general X-ray diffraction) The specific type is not limited as long as a diffraction spectrum having a clear peak that can identify the material type is obtained by measurement) and that the material is a ferromagnetic material, particularly a soft magnetic material. Specific examples of crystalline magnetic materials include Fe-Si-Cr alloys, Fe-Ni alloys, Fe-Co alloys, Fe-V alloys, Fe-Al alloys, Fe-Si alloys, Fe-Si. -Al-based alloys, carbonyl iron and pure iron are mentioned. Said crystalline magnetic material may be comprised from one type of material, and may be comprised from multiple types of material. The crystalline magnetic material that gives the powder of the crystalline magnetic material is preferably one or more materials selected from the group consisting of the above materials, and among these, an Fe—Si—Cr alloy is used. It is preferable to contain, and it is more preferable to consist of a Fe-Si-Cr type alloy. Since the Fe—Si—Cr alloy is a material capable of relatively reducing the iron loss Pcv among the crystalline magnetic materials, the content of the crystalline magnetic material powder in the dust core 1 and the amorphous Even if the mass ratio of the content of the crystalline magnetic material powder to the total content of the magnetic material powder (also referred to as a “first mixing ratio” in this specification) is increased, the inductor provided with the dust core 1 Iron loss Pcv is difficult to increase. The Si content and the Cr content in the Fe—Si—Cr alloy are not limited. As an example which is not limited, it is mentioned that content of Si shall be about 2-7 mass%, and content of Cr shall be about 2-7 mass%.

  The shape of the powder of the crystalline magnetic material contained in the dust core 1 according to the embodiment of the present invention is not limited. The shape of the powder may be spherical or non-spherical. In the case of a non-spherical shape, it may have a shape anisotropy such as a scale shape, an oval sphere shape, a droplet shape, a needle shape, or an indefinite shape having no special shape anisotropy. Good. Examples of the amorphous powder include a case where a plurality of spherical powders are bonded in contact with each other, or are bonded so as to be partially embedded in other powders. Such amorphous powder is easily observed in carbonyl iron.

  The shape of the powder may be a shape obtained at the stage of producing the powder, or may be a shape obtained by secondary processing of the produced powder. Examples of the former shape include a spherical shape, an oval shape, a droplet shape, and a needle shape, and examples of the latter shape include a scale shape.

  As described later, the particle size of the powder of the crystalline magnetic material contained in the dust core 1 according to the embodiment of the present invention is the same as the particle size of the powder of the amorphous magnetic material contained in the dust core 1. Set by relationship.

  It may be preferable that the content of the crystalline magnetic material powder in the powder core 1 is an amount such that the first mixing ratio is 40% by mass or less. When the first mixing ratio is 40% by mass or less, the iron loss Pcv of the inductor including the dust core 1 is reduced as compared with the case where the magnetic material contained in the dust core is made of only an amorphous magnetic material. It becomes easy to do. From the viewpoint of more stably realizing the iron loss Pcv of the inductor including the dust core 1, the first mixing ratio is preferably 35% by mass or less, and more preferably 30% by mass or less. It is preferably 25% by mass or less.

  At least a part of the powder of the crystalline magnetic material is preferably made of a material subjected to surface insulation treatment, and the powder of the crystalline magnetic material is more preferably made of a material subjected to surface insulation treatment. When the surface insulation treatment is performed on the powder of the crystalline magnetic material, the insulation resistance of the dust core 1 tends to be improved. The type of surface insulation treatment applied to the crystalline magnetic material powder is not limited. Examples include phosphoric acid treatment, phosphate treatment, and oxidation treatment.

(2) Amorphous Magnetic Material Powder The amorphous magnetic material that provides the amorphous magnetic material powder contained in the dust core 1 according to an embodiment of the present invention is amorphous (generally As long as the X-ray diffraction measurement does not provide a diffraction spectrum with a clear peak that can identify the material type), and the material is a ferromagnetic material, particularly a soft magnetic material, the specific types are limited. Not. Specific examples of the amorphous magnetic material include an Fe-Si-B alloy, an Fe-PC-C alloy, and a Co-Fe-Si-B alloy. Said amorphous magnetic material may be comprised from one type of material, and may be comprised from multiple types of material. The magnetic material constituting the powder of the amorphous magnetic material is preferably one or more materials selected from the group consisting of the above materials, and among these, an Fe—PC alloy is used. It is preferable to contain it, and it is more preferable that it consists of a Fe-PC-type alloy.

Specific examples of the Fe-P-C-based alloy, composition _formula, shown in _{Fe 100 atomic% -a-b-c-x} -y-z-t Ni a Sn b Cr c P x C y B z Si t 0 atom% ≦ a ≦ 10 atom%, 0 atom% ≦ b ≦ 3 atom%, 0 atom% ≦ c ≦ 6 atom%, 6.8 atom% ≦ x ≦ 13 atom%, 2.2 atom% ≦ Examples include Fe-based amorphous alloys in which y ≦ 13 atomic%, 0 atomic% ≦ z ≦ 9 atomic%, and 0 atomic% ≦ t ≦ 7 atomic%. In the above composition formula, Ni, Sn, Cr, B, and Si are optional added elements.

  The addition amount a of Ni is preferably 0 atom% or more and 6 atom% or less, and more preferably 0 atom% or more and 4 atom% or less. The addition amount b of Sn is preferably 0 atom% or more and 2 atom% or less, and may be added in the range of 1 atom% or more and 2 atom% or less. The addition amount c of Cr is preferably 0 atom% or more and 2 atom% or less, and more preferably 1 atom% or more and 2 atom% or less. In some cases, the addition amount x of P is preferably 8.8 atomic% or more. The addition amount y of C may be preferably 5.8 atomic% or more and 8.8 atomic% or less. The addition amount z of B is preferably 0 atom% or more and 3 atom% or less, and more preferably 0 atom% or more and 2 atom% or less. The addition amount t of Si is preferably 0 atom% or more and 6 atom% or less, and more preferably 0 atom% or more and 2 atom% or less.

  The shape of the powder of the amorphous magnetic material contained in the dust core 1 according to the embodiment of the present invention is not limited. Since the kind of the powder shape is the same as that of the crystalline magnetic material powder, the description thereof is omitted. In some cases, the amorphous magnetic material can be easily formed into a spherical shape or an elliptical spherical shape because of the manufacturing method. In general, since an amorphous magnetic material is harder than a crystalline magnetic material, it may be preferable to make the crystalline magnetic material non-spherical so that it is easily deformed during pressure molding.

  The shape of the powder of the amorphous magnetic material contained in the dust core 1 according to the embodiment of the present invention may be the shape obtained in the stage of producing the powder, or the produced powder is secondary The shape obtained by processing may be sufficient. Examples of the former shape include a sphere, an oval sphere, and a needle shape, and examples of the latter shape include a scale shape.

The particle size of the powder of the amorphous magnetic material contained in the dust core 1 according to one embodiment of the present invention is such that the cumulative particle size distribution from the small particle size side is 50% in the volume-based particle size distribution. (This is also referred to as “median diameter” in this specification.) D ₅₀ A is 15 μm or less. When the median diameter D ₅₀ A of the powder of the amorphous magnetic material is 15 μm or less, it becomes easy to reduce the iron loss Pcv while improving the direct current superposition characteristics of the powder core 1. From the viewpoint of more stably realizing the reduction of the iron loss Pcv while improving the direct current superimposition characteristic of the dust core 1, the median diameter D ₅₀ A of the powder of the amorphous magnetic material may be 10 μm or less. In some cases, it is preferably 7 μm or less, and more preferably 5 μm or less.

Moreover, the particle size of the powder of the amorphous magnetic material contained in the dust core 1 according to one embodiment of the present invention is the next to the particle size of the powder of the amorphous magnetic material contained in the dust core 1. Have a relationship. That is, the median diameter D ₅₀ A of the amorphous magnetic material powder satisfies the following formula (1) with the median diameter D ₅₀ C of the crystalline magnetic material powder.
1 ≦ D ₅₀ A / D ₅₀ C ≦ 3.5 (1)

When D ₅₀ A / D ₅₀ C is in the range of 1 to 3.5, it is easy to reduce the iron loss Pcv while improving the DC superposition characteristics of the inductor including the dust core 1. Specifically, the inductor including the dust core 1 nonlinearly beyond the range estimated from the mixing ratio of the powder of the crystalline magnetic material and the powder of the amorphous magnetic material contained in the dust core 1 It is possible to improve the direct current superposition characteristics and to reduce the iron loss Pcv.

The median diameter D ₅₀ A of the amorphous magnetic material powder may preferably satisfy the following formula (2) with the median diameter D ₅₀ C of the crystalline magnetic material powder. As shown in the examples described later, when the following formula (2) is satisfied, both of the two parameters (μ0 × μ5500 × Isat / ρ and μ0 × Isat / ρ) indicating the direct current superposition characteristics are likely to be favorable.
1.2 ≦ D ₅₀ A / D ₅₀ C ≦ 2.5 (2)

  When comparing an inductor having a dust core made of an amorphous magnetic material with a magnetic material and an inductor having a dust core made of a crystalline magnetic material, the basic trend is that the magnetic material is amorphous magnetic. An inductor having a dust core made of a material has a lower direct current superimposition characteristic although it has a lower iron loss Pcv. Therefore, generally, the magnetic material contained in the dust core is made of an amorphous magnetic material only (when the first mixing ratio is 0% by mass), the crystalline magnetic material is contained, and the first When the mixing ratio is increased, an inductor including a dust core has a tendency to increase the iron loss Pcv although the direct current superimposition characteristic is improved.

  However, in the inductor including the dust core 1 according to the embodiment of the present invention, the improvement of the DC superimposition characteristic occurs preferentially over the increase of the iron loss Pcv, and the DC superimposition characteristic of the inductor including the dust core 1 is improved. Improvement and iron loss Pcv can be reduced. In the dust core 1 according to a preferred embodiment of the present invention, when the first mixing ratio is increased, the iron loss Pcv of the inductor including the dust core 1 tends to decrease. Therefore, in the dust core 1 according to the embodiment of the present invention, if the first mixing ratio is up to about 40% by mass, the magnetic material contained in the dust core 1 is only an amorphous magnetic material ( When the first mixing ratio is increased by increasing the first mixing ratio from the case where the first mixing ratio is 0% by mass, the direct current is increased without increasing the iron loss Pcv for the inductor including the dust core 1. In some cases, the superimposition characteristics can be improved.

  From the viewpoint of more stably obtaining such a preferable dust core 1, the first mixing ratio may be preferably 1% by mass or more and 40% by mass or less, and may be 2% by mass or more and 40% by mass or less. In some cases, it may be more preferable, and it may be more preferable to set it as 5 to 40 mass%, and it may be especially preferable to set it as 5 to 35 mass%.

(3) Binder Component The powder core 1 includes a binder component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to the other materials contained in the powder core 1. It may be. The binder component is a powder of crystalline magnetic material and powder of amorphous magnetic material contained in the dust core 1 according to the present embodiment (in this specification, these powders are collectively referred to as “magnetic powder”). The composition is not limited as long as the material contributes to fixing. As a material constituting the binder component, an organic material such as a resin material and a thermal decomposition residue of the resin material (in this specification, these are collectively referred to as “components based on a resin material”), an inorganic material, and the like Is exemplified. Examples of the resin material include acrylic resin, silicone resin, epoxy resin, phenol resin, urea resin, and melamine resin. The binder component made of an inorganic material is exemplified by a glass-based material such as water glass. The binder component may be composed of one type of material or may be composed of a plurality of materials. The binder component may be a mixture of an organic material and an inorganic material.

  As the binding component, an insulating material is usually used. Thereby, it becomes possible to improve the insulation as the dust core 1.

2. Manufacturing method of powder core Although the manufacturing method of the powder core 1 which concerns on one embodiment of said this invention is not specifically limited, if the manufacturing method demonstrated below is employ | adopted, the powder core 1 will be manufactured more efficiently. Is realized.

  The manufacturing method of the powder core 1 which concerns on one Embodiment of this invention is equipped with the shaping | molding process demonstrated below, and may be further provided with the heat processing process.

(1) Molding step First, a mixture containing magnetic powder and a component that provides a binding component in the powder core 1 is prepared. The component that gives the binding component (also referred to as “binder component” in this specification) may be the binding component itself or may be a material different from the binding component. Specific examples of the latter include a case where the binder component is a resin material and the binder component is a thermal decomposition residue thereof.

  A molded product can be obtained by a molding process including pressure molding of the mixture. The pressurizing condition is not limited and is appropriately determined based on the composition of the binder component. For example, when the binder component is made of a thermosetting resin, it is preferable to heat the resin together with pressure to advance the resin curing reaction in the mold. On the other hand, in the case of compression molding, although the pressing force is high, heating is not a necessary condition and pressurization is performed for a short time.

  Hereinafter, the case where the mixture is granulated powder and compression molding will be described in some detail. Since the granulated powder is excellent in handleability, it is possible to improve the workability of the compression molding process in which the molding time is short and the productivity is excellent.

(1-1) Granulated powder Granulated powder contains magnetic powder and a binder component. The content of the binder component in the granulated powder is not particularly limited. When this content is too low, it becomes difficult for the binder component to hold the magnetic powder. In addition, when the content of the binder component is excessively low, in the powder core 1 obtained through the heat treatment step, the binder component composed of the thermal decomposition residue of the binder component causes a plurality of magnetic powders to be separated from each other. It becomes difficult to insulate. On the other hand, when the content of the binder component is excessively high, the content of the binder component contained in the powder core 1 obtained through the heat treatment step tends to be high. When the content of the binder component in the dust core 1 is increased, the magnetic properties of the dust core 1 are likely to be reduced. Therefore, the content of the binder component in the granulated powder is preferably set to an amount that is 0.5% by mass or more and 5.0% by mass or less with respect to the entire granulated powder. From the viewpoint of more stably reducing the possibility that the magnetic properties of the dust core 1 will decrease, the content of the binder component in the granulated powder is 1.0 mass% or more with respect to the entire granulated powder. The amount is preferably 5% by mass or less, and more preferably 1.2% by mass or more and 3.0% by mass or less.

  The granulated powder may contain materials other than the above magnetic powder and binder component. Examples of such materials include lubricants, silane coupling agents, and insulating fillers. In the case of containing a lubricant, the type is not particularly limited. It may be an organic lubricant or an inorganic lubricant. Specific examples of the organic lubricant include metal soaps such as zinc stearate and aluminum stearate. It is considered that such an organic lubricant is vaporized in the heat treatment step and hardly remains in the powder core 1.

  The manufacturing method of granulated powder is not specifically limited. The ingredients that give the granulated powder may be kneaded as they are, and the resulting kneaded product may be pulverized by a known method to obtain granulated powder, or a dispersion medium (water as an example) It is also possible to obtain a granulated powder by preparing a slurry to which is added, and drying and pulverizing the slurry. Screening and classification may be performed after pulverization to control the particle size distribution of the granulated powder.

As an example of a method for obtaining granulated powder from the above slurry, a method using a spray dryer can be mentioned. As shown in FIG. 2, a rotator 201 is provided in the spray dryer apparatus 200, and the slurry S is injected toward the rotator 201 from the upper part of the apparatus. The rotor 201 rotates at a predetermined number of revolutions, and sprays the slurry S as droplets by centrifugal force in a chamber inside the spray dryer apparatus 200. Further, hot air is introduced into the chamber inside the spray dryer apparatus 200, whereby the dispersion medium (water) contained in the droplet-like slurry S is volatilized while maintaining the droplet shape. As a result, the granulated powder P is formed from the slurry S. This granulated powder P is collected from the lower part of the apparatus 200. Each parameter such as the number of rotations of the rotor 201, the temperature of hot air introduced into the spray dryer apparatus 200, and the temperature at the bottom of the chamber may be set as appropriate. As specific examples of the setting ranges of these parameters, the rotation speed of the rotor 201 is 4000 to 8000 rpm, the hot air temperature introduced into the spray dryer apparatus 200 is 130 to 170 ° C., and the temperature at the bottom of the chamber is 80 to 90 ° C. . The atmosphere in the chamber and its pressure may be set as appropriate. As an example, the inside of the chamber is an air atmosphere, and the pressure is ₂ mmH ₂ O (about 0.02 kPa) as a differential pressure from the atmospheric pressure. You may further control the particle size distribution of the obtained granulated powder P by sieving.

(1-2) Pressing conditions The pressing conditions in compression molding are not particularly limited. What is necessary is just to set suitably considering the composition of granulated powder, the shape of a molded article, etc. If the pressure applied when the granulated powder is compression-molded is excessively low, the mechanical strength of the molded product decreases. For this reason, it becomes easy to produce the problem that the handleability of a molded article falls and the mechanical strength of the compacting core 1 obtained from the molded article falls. Moreover, the magnetic characteristics of the dust core 1 may deteriorate or the insulating properties may decrease. On the other hand, if the applied pressure during compression molding of the granulated powder is excessively high, it becomes difficult to create a molding die that can withstand the pressure. From the viewpoint of more stably reducing the possibility that the compression and pressurization process will adversely affect the mechanical properties and magnetic properties of the dust core 1 and facilitating mass production industrially, The applied pressure is preferably 0.3 GPa to 2 GPa, more preferably 0.5 GPa to 2 GPa, and particularly preferably 0.8 GPa to 2 GPa.

  In compression molding, pressurization may be performed while heating, or pressurization may be performed at room temperature.

(2) Heat treatment step The molded product obtained in the molding step may be the powder core 1 according to the present embodiment, or the molded product may be subjected to a heat treatment step and pressed as described below. A powder core 1 may be obtained.

  In the heat treatment process, the molded product obtained by the above molding process is heated to adjust the magnetic properties by correcting the distance between the magnetic powders and to relax the strain applied to the magnetic powder in the molding process. The powder core 1 is obtained by adjusting the magnetic characteristics.

  Since the purpose of the heat treatment step is to adjust the magnetic properties of the dust core 1 as described above, the heat treatment conditions such as the heat treatment temperature are set so that the magnetic properties of the dust core 1 are the best. As an example of a method for setting the heat treatment conditions, it is possible to change the heating temperature of the molded product and to make other conditions constant, such as the heating rate and the holding time at the heating temperature.

  The evaluation criteria for the magnetic properties of the dust core 1 when setting the heat treatment conditions are not particularly limited. The iron loss Pcv of the powder core 1 can be given as a specific example of the evaluation item. In this case, what is necessary is just to set the heating temperature of a molded product so that the iron loss Pcv of the powder core 1 may become the minimum. The measurement conditions for the iron loss Pcv are set as appropriate. As an example, a condition in which the frequency is 100 kHz and the effective maximum magnetic flux density Bm is 100 mT can be given.

  The atmosphere during the heat treatment is not particularly limited. In the case of an oxidizing atmosphere, the possibility of excessive thermal decomposition of the binder component and the possibility of progress of oxidation of the magnetic powder increases, so that an inert atmosphere such as nitrogen or argon, or a reducing property such as hydrogen Heat treatment is preferably performed in an atmosphere.

3. Inductor, Electronic / Electric Device An inductor according to an embodiment of the present invention includes the dust core 1 according to the embodiment of the present invention, a coil, and a connection terminal connected to each end of the coil. Here, at least a part of the dust core 1 is disposed so as to be located in an induced magnetic field generated by the current when a current is passed through the coil via the connection terminal. Since the inductor according to an embodiment of the present invention includes the dust core 1 according to the embodiment of the present invention described above, the inductor has excellent direct current superposition characteristics, and iron loss is unlikely to increase even at high frequencies. Therefore, it is possible to reduce the size as compared with the inductor according to the prior art.

  An example of such an inductor is the toroidal coil 10 shown in FIG. The toroidal coil 10 includes a coil 2 a formed by winding a coated conductive wire 2 around a ring-shaped dust core (toroidal core) 1. The ends 2d and 2e of the coil 2a can be defined in the portion of the conductive wire located between the coil 2a formed of the wound covered conductive wire 2 and the ends 2b and 2c of the covered conductive wire 2. Thus, in the inductor according to the present embodiment, the member constituting the coil and the member constituting the connection terminal may be composed of the same member.

  As another example of the inductor according to the embodiment of the present invention, a coil embedded type inductor 20 shown in FIG. 4 can be cited. The coil-embedded inductor 20 can be formed in a small chip shape of several mm square, and includes a dust core 21 having a box shape, and a coil portion 22c in the covered conductive wire 22 is provided therein. Buried. End portions 22a and 22b of the coated conductive wire 22 are located on the surface of the powder core 21 and exposed. Part of the surface of the dust core 21 is covered with connection end portions 23a and 23b that are electrically independent from each other. The connection end portion 23 a is electrically connected to the end portion 22 a of the covered conductive wire 22, and the connection end portion 23 b is electrically connected to the end portion 22 b of the covered conductive wire 22. In the coil-embedded inductor 20 shown in FIG. 4, the end portion 22a of the covered conductive wire 22 is covered with the connection end portion 23a, and the end portion 22b of the covered conductive wire 22 is covered with the connection end portion 23b.

  The method for embedding the coil portion 22c of the coated conductive wire 22 in the dust core 21 is not limited. A member around which the coated conductive wire 22 is wound may be placed in a mold, and a mixture (granulated powder) containing magnetic powder may be supplied into the mold to perform pressure molding. Alternatively, a plurality of members prepared by preforming a mixture (granulated powder) containing magnetic powder in advance are prepared, and these members are combined, and the coated conductive wires 22 are arranged in the gaps defined at that time. A solid may be obtained and this assembly may be pressure molded. The material of the covered conductive wire 22 including the coil portion 22c is not limited. For example, a copper alloy can be used. The coil portion 22c may be an edgewise coil. The material of the connection end portions 23a and 23b is not limited. From the viewpoint of excellent productivity, it may be preferable to include a metallized layer formed from a conductive paste such as a silver paste and a plating layer formed on the metallized layer. The material for forming the plating layer is not limited. Examples of the metal element contained in the material include copper, aluminum, zinc, nickel, iron, and tin.

  An electronic / electrical device according to an embodiment of the present invention is an electronic / electrical device in which the inductor according to the above-described embodiment of the present invention is mounted, and is connected to a substrate at the connection terminal. is there. Since the inductor according to one embodiment of the present invention is mounted on the electronic / electric device according to one embodiment of the present invention, a large current may flow in the device or a high frequency may be applied. Inductors are less likely to suffer from functional degradation and heat generation, and the device can be easily downsized.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.
Example 1

(1) Preparation of Fe-based amorphous alloy powder Fe _{71 atomic%} Ni _{6 atomic%} Cr _{2 atomic%} P _{11 atomic%} C _{8 atomic%} B _{2 atomic%} Using this method, powders (amorphous powders) of five kinds of amorphous magnetic materials having different particle size distributions were prepared. The particle size distribution of the obtained amorphous magnetic material powder was measured by volume distribution using “Microtrack particle size distribution measuring device MT3300EX” manufactured by Nikkiso Co., Ltd. In the volume-based particle size distribution, the particle size (median diameter) D ₅₀ A at which the cumulative particle size distribution from the small particle size side becomes 50% was 5 μm. In addition, as a powder of crystalline magnetic material, Fe-Si-Cr alloy, specifically, Si content is 6.4% by mass, Cr content is 3.1% by mass, and the balance is A powder comprising an alloy composed of Fe and inevitable impurities and having a median diameter D ₅₀ C of 2 μm was prepared.

(2) Production of Granulated Powder The above-mentioned amorphous magnetic material powder and crystalline magnetic material powder were mixed so as to have the first mixing ratio shown in Table 1 to obtain a magnetic powder. 97.2 parts by mass of magnetic powder, 2 to 3 parts by mass of an insulating binder made of acrylic resin and phenol resin, and 0 to 0.5 parts by mass of a lubricant made of zinc stearate are added to water as a solvent. A slurry was obtained by mixing.

  The obtained slurry was granulated under the conditions described above using a spray dryer apparatus 200 shown in FIG. 2 to obtain granulated powder.

(3) Compression molding The obtained granulated powder is filled in a mold and press-molded at a surface pressure of 0.5 to 1.5 GPa to form a ring shape having an outer diameter of 20 mm, an inner diameter of 12 mm and a thickness of 3 mm. Got the body.

(4) Heat treatment The obtained molded body was placed in a furnace in a nitrogen stream atmosphere, and the furnace temperature was an optimum core heat treatment temperature from room temperature (23 ° C.) to a heating rate of 10 ° C./min. The mixture was heated to 0 ° C., held at this temperature for 1 hour, and then heat-treated to cool to room temperature in a furnace to obtain a toroidal core composed of a dust core.

(Test Example 1) Measurement of core density ρ The dimensions and weight of the toroidal core produced in Example 1 were measured, and the density ρ (unit: g / cc) of each toroidal core was calculated from these numerical values. The results are shown in Table 1.

(Test Example 2) Measurement of magnetic permeability For a toroidal coil obtained by winding a coated copper wire 40 times on the primary side and 10 times on the secondary side on the toroidal core produced in Example 1, an impedance analyzer (manufactured by HP, “ 4192A "), the initial permeability μ0 was measured under the condition of 100 kHz. Further, a direct current was superimposed on the toroidal coil under the condition of 100 kHz, and the relative permeability μ5500 when the DC applied magnetic field was 5500 A / m was measured. The results are shown in Table 1.

(Test Example 3) Measurement of DC superimposition characteristics Using the toroidal coil formed from the toroidal core produced in Example 1, a DC current was superimposed on the toroidal coil in accordance with JIS C2560-2. From the applied current value Isat (unit: A) when the ratio (ΔL / L ₀ ) of the change amount ΔL of the inductance L to the value L ₀ of the inductance L before application of the superimposed current (initial) is 30%, DC The superposition characteristics were evaluated. The measurement of the DC superposition characteristic was performed using “4284” manufactured by HP. The results are shown in Table 1.

(Test Example 4) Measurement of Iron Loss Pcv For the toroidal coil obtained by winding the coated copper wire around the toroidal core produced in Example 1 15 times on the primary side and 10 times on the secondary side, BH analyzer (Iwasaki Tsushinki) The core loss Pcv (unit: kW / m ³ ) was measured at a measurement frequency of 2 MHz under the condition that the effective maximum magnetic flux density Bm was 15 mT. The results are shown in Table 1.

(Evaluation example 1) Relative Pcv
About the iron loss Pcv measured by the test example 4, the value normalized by the case where the 1st mixing ratio was 0 mass% was evaluated as Relative Pcv. The degree of change in iron loss Pcv due to the change in the first mixing ratio can be determined by the relative Pcv even if the types of the crystalline magnetic material and the amorphous magnetic material contained in the dust core (toroidal core) are different. Relative evaluation can be performed. The evaluation results are shown in Table 2.

(Evaluation Example 2) μ0 × μ5500 × Isat / ρ
Isat / ρ (ΔL / L ₀ is 30 based on the initial permeability μ0 measured in Test Example 2, the relative permeability μ5500 when the DC applied magnetic field is 5500 A / m, and the results measured in Test Examples 1 and 3. Μ0 × μ5500 × Isat / ρ, which is the numerical value part of the product of the applied current value Isat when divided by the core density ρ measured in Test Example 1), is a relative evaluation of the DC superposition characteristics rather than Isat. Suitable for The evaluation results are shown in Table 2.

  μ0 and μ5500 are values normalized by volume, whereas Isat is a value not normalized by volume or mass. For this reason, it is influenced by the size of the dust core (toroidal core). Therefore, by using a parameter including Isat / ρ obtained by dividing Isat by ρ, the DC superposition characteristics are generalized and are easily compared.

(Evaluation example 3) μ0 × Isat / ρ
Μ0 × Isat / ρ, which is the numerical part of the product of the initial permeability μ0 measured in Test Example 2 and Isat / ρ based on the results measured in Test Example 1 and Test Example 3, is μ0 × μ5500 × Isat. Like / ρ, it is more suitable for relative evaluation of DC superposition characteristics than Isat. The evaluation results are shown in Table 2.

(Examples 2 to 10)
As shown in Table 3, the magnetic powder used in Example 1 is a magnetic powder having a different particle size of amorphous magnetic material powder, composition of crystalline magnetic material powder, surface treatment, and different particle sizes. In the same manner as in Example 1, a toroidal core composed of a dust core was obtained. In addition, the powder of the amorphous magnetic material used in Example 10 was manufactured by an atomizing method in which gas atomization and water atomization are continuously performed. In the column of D ₅₀ C in Table 3, the particle size distribution of the crystalline magnetic material powder is measured by volume distribution using “Microtrac particle size distribution measuring device MT3300EX” manufactured by Nikkiso Co., Ltd. The particle size (median diameter, unit: μm) at which the cumulative particle size distribution from the diameter side becomes 50% is displayed.

The meanings of the symbols in Table 3 are as follows.
-Composition type A-1: Fe-Si-Cr-based alloy having a Si content of 6.4% by mass and a Cr content of 3.1% by mass with the balance being Fe and inevitable impurities Same composition as Example 1)
A-2: Fe-Si-Cr-based alloy having a Si content of 6.3% by mass and a Cr content of 3.2% by mass with the balance being Fe and inevitable impurities B-1: Si The Fe content is 2.0 mass%, the Cr content is 3.5 mass%, and the balance is Fe-Si-Cr alloy consisting of Fe and inevitable impurities. B-2: Si content is 3%. Fe-Si-Cr-based alloy consisting of Fe and unavoidable impurities C: Carbonyl iron

-Surface treatment type I: No surface treatment (same as Example 1)
II: Zinc phosphate based surface insulation treatment III: Surface insulation treatment including phosphorylation

  The results of test examples for Examples 2 to 10 are shown in Tables 4 to 12, and the results of evaluation examples are shown in Tables 13 to 21. In these tables, when the first mixing ratio is 0% by mass and 100% by mass, different example numbers are assigned to the same results from the viewpoint of improving the visibility of the tables. (Example 2-3, Example 3-1, etc.).

FIG. 5 to FIG. 24 summarize the dependence of the above results on the first mixing ratio of Relative Pcv and the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio for each example.
FIG. 5 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 1.
FIG. 6 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 2.
FIG. 7 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 3.
FIG. 8 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 4.
FIG. 9 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 5.
FIG. 10 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 6.
FIG. 11 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 7.
FIG. 12 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 8.
FIG. 13 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 9.
FIG. 14 is a graph showing the dependence of the relative Pcv on the first mixing ratio in Example 10.
15 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 1. FIG.
FIG. 16 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 2.
FIG. 17 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 3.
FIG. 18 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 4.
FIG. 19 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 5.
FIG. 20 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 6.
FIG. 21 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 7.
FIG. 22 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 8.
FIG. 23 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 9.
FIG. 24 is a graph showing the dependence of μ0 × μ5500 × Isat / ρ on the first mixing ratio in Example 10.
FIG. 25 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 1.
FIG. 26 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 2.
FIG. 27 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 3.
28 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 4. FIG.
FIG. 29 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 5.
FIG. 30 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 6.
FIG. 31 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 7.
32 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 8. FIG.
FIG. 33 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 9.
FIG. 34 is a graph showing the dependence of μ0 × Isat / ρ on the first mixing ratio in Example 10.

In each graph, the evaluation result is fitted to a quadratic curve, the resulting quadratic curve is shown by a solid line in the graph, and a function indicating the quadratic curve (where x is the first mixing ratio) Y is the value of Relative Pcv, the value of μ0 × μ5500 × Isat / ρ, or the value of μ0 × μ5500 × Isat / ρ). By comparing the coefficient of x ^2, can relative evaluation nonlinearity curves.

  Regarding the results of Example 1, the relationship between iron loss Pcv and μ0 × μ5500 × Isat / ρ and the relationship between iron loss Pcv and μ0 × Isat / ρ were plotted. The results are shown in FIGS. 35 and 36.

  As shown in FIGS. 35 and 36, μ0 × μ5500 × Isat / ρ and μ0 × Isat / ρ are preferentially increased with the increase of the first mixing ratio until the first mixing ratio reaches 40% by mass. As a result, the iron loss Pcv was equal to or less than that when the first mixing ratio was 0% by mass. Therefore, it was confirmed that the dust core manufactured by Example 1 is a dust core that provides a very good inductor that is particularly excellent in direct current superposition characteristics and that has particularly low iron loss Pcv.

  Regarding the results of Example 10, the relationship between the iron loss Pcv and μ0 × μ5500 × Isat / ρ and the relationship between the iron loss Pcv and μ0 × Isat / ρ were plotted. The results are shown in FIGS. 39 and 40.

As shown in FIGS. 39 and 40, μ0 × μ5500 × Isat / ρ and μ0 × Isat / ρ are preferentially increased as the first mixing ratio is increased until the first mixing ratio reaches 30% by mass. As a result, the iron loss Pcv was equal to or less than that when the first mixing ratio was 0% by mass. However, the powder core manufactured according to Example 10 had a larger iron loss Pcv value than the powder core manufactured according to Example 1. This is thought to be due to the fact that D ₅₀ A / D ₅₀ C is as large as 3.8.

  From the viewpoint of comparing the results of Examples 1 to 8 and Example 10 in which the composition of the crystalline magnetic material is an Fe—Si—Cr alloy, the first mixing ratio in these Examples is 30% by mass. (Table 22), the relationship between iron loss Pcv and μ0 × μ5500 × Isat / ρ and the relationship between iron loss Pcv and μ0 × Isat / ρ were plotted. The results are shown in FIGS. 37 and 38.

  The symbols in FIGS. 37 and 38 are described as follows. White circles (◯) are results when the first mixing ratio in each example is 30% by mass. The black rhombus (♦) is the result when the first mixing ratio in Examples 1 to 9 is 0% by mass. The white rhombus (◇) is the result when the first mixing ratio in Example 10 is 0% by mass. The black triangle (▲) is the result when the first mixing ratio in each example is 100% by mass. The crosses (x) are the results when the crystalline magnetic material is carbonyl iron and the first mixing ratio is 5% by mass to 30% by mass (Example 9-2 to Example 9-6).

  The broken line in FIGS. 37 and 38 is a line that roughly connects the result when the first mixing ratio is 0% by mass and the result when the first mixing ratio is 100% by mass. Is preferably above the upper left, preferably on the upper left side as indicated by the white arrow in each figure, the mixing ratio of the powder of the crystalline magnetic material and the powder of the amorphous magnetic material contained in the dust core This shows that a dust core is obtained that is more than expected based on the above, that is, more than simple additivity, giving an inductor having excellent DC superposition characteristics and reduced iron loss.

On the other hand, when it is located below the broken line in FIGS. 37 and 38, particularly at the lower right side as shown by the black arrow in each figure, the powder of crystalline magnetic material contained in the dust core It shows that a dust core is obtained that gives an inductor with inferior direct current superposition characteristics and increased iron loss than expected by mixing with powder of an amorphous magnetic material. As shown in FIGS. 37 and 38, the result of Example 10-2 is located on the lower right side of the broken line, and the dust core manufactured by Example 10 has excellent DC superposition characteristics and reduced iron loss. It cannot be said that it is a dust core that gives an inductor. This _is similar to the results of FIG. 39 and FIG. 40 described above _{D 50} A _/ D 50 _C, is considered as the value of _{D 50} A _/ D 50 C is affected as large as 3.8.

(Examples 11 and 12)
Fe _{71 atomic%} Ni _{6 atomic%} Cr _{2 atomic%} P _{11 atomic%} C _{8 atomic%} B _{2 atomic% The} raw materials are weighed so as to have 5 types of non-different particle size distributions using the water atomization method. A crystalline magnetic material powder (amorphous powder) was prepared. The particle size distribution of the obtained amorphous magnetic material powder was measured by volume distribution using “Microtrack particle size distribution measuring device MT3300EX” manufactured by Nikkiso Co., Ltd. In the volume-based particle size distribution, the particle size (median diameter) D ₅₀ A at which the cumulative particle size distribution from the small particle size side becomes 50% was 10 μm. This amorphous powder and amorphous powders having median diameter D ₅₀ A of 5 μm, 7 μm and 15 μm used in Examples 2 to 10 were prepared.

Further, the content of Si is 3.5% by mass, the content of Cr is 4.5% by mass, and the balance is made of an Fe—Si—Cr alloy composed of Fe and inevitable impurities. A powder of a crystalline magnetic material having a median diameter D ₅₀ C of 4 μm and 6 μm, which has been subjected to a treatment corresponding to the aforementioned surface treatment type II (zinc phosphate-based surface insulation treatment), is used as a material for Example 11. Prepared. Further, the Fe content is 6.4% by mass, the Cr content is 3.1% by mass, and the balance is Fe—Si—Cr based alloy composed of Fe and inevitable impurities (the above-mentioned composition type A- A crystalline magnetic material powder comprising 1) and not surface-treated (corresponding to the surface treatment type I described above) and having a median diameter D ₅₀ C of 2 μm was prepared as a material for Example 12.

  These amorphous magnetic material powder and crystalline magnetic material powder were mixed so that the first mixing ratio was 30% by mass, and Examples 11-1 to 11-5 shown in Table 23 were used. Magnetic powder and magnetic powder of Example 12 were obtained. These magnetic powders were tested and evaluated in the same manner as in Examples 2 to 10. The results are shown in Table 23.

Based on the results of Example 11 shown in Table 23, the relationship between μ0 × μ5500 × Isat / ρ and D ₅₀ A / D ₅₀ C, and the relationship between μ0 × Isat / ρ and D ₅₀ A / D ₅₀ C are shown. FIG. 41 is a graph. As shown in FIG. 41, when D ₅₀ A / D ₅₀ C is 1 or more and 3.5 or less, the result that μ0 × μ5500 × Isat / ρ and μ0 × Isat / ρ are good is obtained, and this tendency Was remarkable when D ₅₀ A / D ₅₀ C was 1.2 or more and 2.5 or less.

  According to the present invention, it is possible to obtain a dust core that provides a good inductor with excellent direct current superposition characteristics and reduced iron loss, and the degree of goodness is the same as the crystalline magnetic material powder contained in the dust core. It was confirmed by this example that the degree exceeded the expectation based on the mixing ratio of the amorphous magnetic material with the powder.

  The inductor having the dust core of the present invention can be suitably used as a component of a booster circuit such as a hybrid vehicle, a component of a power generation / transforming facility, a component of a transformer, a choke coil, or the like.

1 ... Compact core (toroidal core)
DESCRIPTION OF SYMBOLS 10 ... Toroidal coil 2 ... Coated conductive wire 2a ... Coils 2b, 2c ... End 2d, 2e of coated conductive wire 2 ... End 20 of coil 2a ... Coil buried type inductor 21 ... Powder core 22 ... Coated conductive wire 22a, 22b ... Ends 23a, 23b ... Connection end 22c ... Coil part 200 ... Spray dryer device 201 ... Rotor S ... Slurry P ... Granulated powder

Claims (17)

A powder core containing a powder of crystalline magnetic material and a powder of amorphous magnetic material,
The powder of the amorphous magnetic material has a median diameter D ₅₀ A of 15 μm or less, and satisfies the following formula (1) and the median diameter D ₅₀ C of the crystalline magnetic material powder: core.
1 ≦ D ₅₀ A / D ₅₀ C ≦ 3.5 (1) The median diameter D _{50 A} of the amorphous magnetic material powder, the crystalline powder median diameter D _{50 C} and the following formula of the magnetic material satisfying the (2), according to any one of claims 1 to 11 Powder core.
1.2 ≦ D ₅₀ A / D ₅₀ C ≦ 2.5 (2) The powder core according to claim 1 or 2, wherein the powder of the amorphous magnetic material has a median diameter D ₅₀ A of 7 µm or less.   The first mixing ratio, which is the mass ratio of the content of the crystalline magnetic material powder to the total content of the crystalline magnetic material powder and the amorphous magnetic material powder, is 40% by mass. The powder core according to any one of claims 1 to 3, which is the following.   The powder core according to claim 4, wherein the first mixing ratio is 2% by mass or more.   The crystalline magnetic material is Fe-Si-Cr alloy, Fe-Ni alloy, Fe-Co alloy, Fe-V alloy, Fe-Al alloy, Fe-Si alloy, Fe-Si-Al. The dust core according to any one of claims 1 to 5, comprising one or more materials selected from the group consisting of a system alloy, carbonyl iron and pure iron.   The dust core according to claim 6, wherein the crystalline magnetic material is made of an Fe-Si-Cr alloy.   The amorphous magnetic material includes one or more materials selected from the group consisting of Fe-Si-B alloys, Fe-PC-C alloys, and Co-Fe-Si-B alloys. The powder core according to any one of claims 1 to 7.   The dust core according to claim 8, wherein the amorphous magnetic material is made of an Fe—P—C alloy.   The powder core according to any one of claims 1 to 9, wherein the powder of the crystalline magnetic material is made of an insulating material.   11. The composition according to claim 1, further comprising: a binder component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to another material contained in the powder core. The dust core according to one item.   The powder core according to claim 11, wherein the binding component includes a component based on a resin material.   13. A method for producing a dust core according to claim 12, comprising pressure molding of a mixture comprising a binder component comprising the crystalline magnetic material powder and the amorphous magnetic material powder and the resin material. A method for producing a powder core, comprising a molding step of obtaining a molded product by a molding process.   The manufacturing method of the powder core of Claim 13 whose said molded product obtained by the said formation process is the said powder core.   The manufacturing method of the powder core of Claim 13 provided with the heat processing process of obtaining the said powder core by the heat processing which heats the said molded product obtained by the said shaping | molding process.   It is an inductor provided with the connecting terminal connected to each end part of the dust core, coil, and said coil as described in any one of Claim 1-12, Comprising: At least one part of the said dust core is the said connection. An inductor disposed so as to be located in an induced magnetic field generated by the current when a current is passed through the coil via a terminal.   17. An electronic / electrical device on which the inductor according to claim 16 is mounted, wherein the inductor is connected to a substrate at the connection terminal.