TWI631223B - Powder magnetic core, method for manufacturing the powder magnetic core, inductor provided with the powder magnetic core, and electronic / electrical equipment equipped with the inductor - Google Patents

Abstract

The present invention is directed to a powder magnetic core containing a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, and provides a powder magnetic core capable of supplying an inductor having excellent insulation withstand voltage characteristics and excellent iron loss. A powder magnetic core 1 is a powder containing a crystalline magnetic material and an amorphous magnetic material, and the content of the powder of the crystalline magnetic material relative to the content of the powder of the crystalline magnetic material is the same as that of the non-crystalline powder. The mass ratio of the sum of the content of the powder of the crystalline magnetic material, that is, the first mixing ratio is 40% by mass or more and 90% by mass or less.

Description

Powder magnetic core, method for manufacturing the powder magnetic core, inductor provided with the powder magnetic core, and electronic / electrical equipment equipped with the inductor

The present invention relates to a powder magnetic core, a method for manufacturing the powder magnetic core, an inductor provided with the powder magnetic core, and an electronic / electrical device equipped with the inductor. In the present specification, the so-called "inductor" refers to a passive element including a core material including a powder magnetic core and a coil, and a concept including a reactor.

Powder magnetic cores used in booster circuits for hybrid vehicles, such as reactors, reactors, transformers, or chokes used in power generation and transformation equipment can be obtained by powder-molding soft magnetic powder. . An inductor having such a powder magnetic core is required to have both low iron loss and excellent insulation withstand voltage characteristics (in the present invention, when a DC voltage or an AC voltage having a frequency of 60 Hz or less is applied to the inductor The voltage at which insulation breakdown occurs (insulation breakdown voltage is high). In Patent Document 1, as a method for improving the reduction of the insulation resistance in a high-temperature environment, a composite magnetic material is disclosed. The composite magnetic material is based on the magnetic properties of an iron-based crystalline alloy magnetic powder and an iron-based amorphous alloy. In the mixed magnetic powder obtained by mixing the powders, the mixing ratios of the crystalline alloy magnetic powder and the amorphous alloy magnetic powder are set to 60 to 90 wt% and 40 to 10 wt%, respectively. In Patent Document 2, as a method for improving the insulation and corrosion resistance of a powder magnetic core, a composite magnetic material is disclosed. The composite magnetic material is composed of an amorphous magnetic alloy powder and crystalline Fe- In a mixed magnetic material powder obtained by mixing Cr-based alloy powder and a magnetic core material of an insulating bonding agent, a Fe-Cr-based alloy is mixed in accordance with a mixing ratio of the amorphous magnetic alloy powder and the Fe-Cr-based alloy powder. The weight ratio of the powder to the mixed magnetic material powder is set to 10 to 60 wt%. [Prior Art Literature] [Patent Literature] [Patent Literature 1] Japanese Patent Laid-Open No. 2004-197218 [Patent Literature 2] Japanese Patent Laid-Open No. 2007-134381

[Problems to be Solved by the Invention] Both Patent Document 1 and Patent Document 2 focus on reducing the insulation resistance of the powder magnetic core when the amount of the crystalline alloy powder is increased, and by adjusting the crystalline alloy magnetic powder in the mixed magnetic powder The blending ratio with the amorphous alloy magnetic powder prevents the insulation resistance from decreasing. However, neither Patent Literature 1 nor Patent Literature 2 evaluates the withstand voltage characteristics of the powder magnetic core. Therefore, an object of the present invention is to provide a powder magnetic core, which contains powder of crystalline magnetic material and powder of amorphous magnetic material, and provides a good inductor with excellent insulation voltage resistance and reduced iron loss. Device. The present invention also aims to provide a method for manufacturing the powder magnetic core, an inductor provided with the powder magnetic core, and an electronic / electrical device equipped with the inductor. [Technical means to solve the problem] In order to solve the above-mentioned problem, the present inventors and others have conducted discussions, and as a result, they have obtained new insights. The mass ratio of the sum of the content and the content of the powder of the above-mentioned amorphous magnetic material, that is, the first mixing ratio is appropriately adjusted, so that the insulation and withstand voltage characteristics of the powder magnetic core can be improved. The estimated range of the mixing ratio of the powder of the crystalline magnetic material and the powder of the amorphous magnetic material contained in the powder magnetic core improves the insulation and withstand voltage characteristics of the powder magnetic core non-linearly, and it is a good way to provide a reduction in iron loss. Powder cores for inductors. The inventions completed based on the above findings are as follows. One aspect of the present invention is a powder magnetic core, which contains a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, and the content of the powder of the crystalline magnetic material is relative to that of the powder of the crystalline magnetic material. The mass ratio of the sum of the content and the content of the powder of the amorphous magnetic material, that is, the first mixing ratio is 40% by mass or more and 90% by mass or less. When the above-mentioned first mixing ratio satisfies the above-mentioned relationship, it can exceed the range estimated from the powdered monomer of the crystalline magnetic material or the amorphous magnetic material, and non-linearly improve the insulation withstand voltage characteristics of the powder magnetic core. And it can be made into a powder magnetic core that reduces the iron loss of the inductor. The first mixing ratio of the powder magnetic core may be 50% by mass or more and 70% by mass or less. The above-mentioned powder magnetic core may also have an insulation withstand voltage value of 120% or more when the insulation withstand voltage value of the powder magnetic core using only the powder containing the above-mentioned amorphous magnetic material as a magnetic powder is 100%. The above-mentioned powder magnetic core may also have an insulation withstand voltage value of 110% or more when the insulation withstand voltage value of the powder magnetic core using the powder containing only the crystalline magnetic material as a magnetic powder is based on (100%). The crystalline magnetic material may include a material selected from the group consisting of Fe-Si-Cr-based alloys, Fe-Ni-based alloys, Fe-Co-based alloys, Fe-V-based alloys, Fe-Al-based alloys, Fe-Si-based alloys, and Fe- One or more kinds of materials in the group consisting of Si-Al alloy, carbonyl iron and pure iron. The crystalline magnetic material preferably contains an Fe-Si-Cr-based alloy. The amorphous magnetic material may include one or two or more materials selected from the group consisting of an Fe-Si-B-based alloy, an Fe-P-C-based alloy, and a Co-Fe-Si-B-based alloy. The amorphous magnetic material preferably contains an Fe-P-C-based alloy. The powder of the crystalline magnetic material preferably contains a material subjected to an insulation treatment. By implementing the insulation treatment, it is possible to more stably achieve an improvement in the insulation withstand voltage characteristic or insulation resistance of the powder magnetic core, or a reduction in iron loss at a high frequency band. The powder magnetic core may further include a binding component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to other materials contained in the powder magnetic core. In this case, it is preferable that the above-mentioned binding component includes a component based on a resin material. Another aspect of the present invention is a method for manufacturing a powder magnetic core, which is characterized in that it is a method for manufacturing a powder magnetic core as described above, and is provided with a forming step which is formed by pressure forming including a mixture. The processed article is obtained, and the mixture includes a powder of the crystalline magnetic material, a powder of the amorphous magnetic material, and a binder component containing the resin material. According to the above manufacturing method, the powder magnetic core can be manufactured more efficiently. In the above manufacturing method, the molded article obtained by the molding step may be the powder magnetic core. Alternatively, a heat treatment step may be provided. The heat treatment step obtains the powder magnetic core by heat-treating the molded article obtained by the forming step. Another aspect of the present invention is an inductor, which is provided with the above-mentioned powder magnetic core, a coil, and a connection terminal connected to each end portion of the coil, and at least a part of the powder magnetic core is located in the Dang via The connection terminals are arranged in an induced magnetic field generated by the current when a current flows through the coil. The above-mentioned inductor can simultaneously achieve excellent insulation withstand voltage characteristics and low loss based on the excellent characteristics of the powder magnetic core. Yet another aspect of the present invention is an electronic / electrical device in which the inductor is mounted, and the inductor is connected to a substrate using the connection terminal. Examples of the electronic and electrical devices include a power supply device including a power switch circuit, a voltage step-up circuit, a smoothing circuit, and the like, and a small portable communication device. Since the electronic / electrical device of the present invention is provided with the above-mentioned inductor, it is easy to cope with high voltage or high frequency. [Effects of the Invention] Since the powder magnetic core of the above invention appropriately adjusts the first mixing ratio, the insulation voltage resistance characteristics of the powder magnetic core can be improved. Furthermore, according to the present invention, there are provided a method for manufacturing the powder magnetic core, an inductor including the powder magnetic core, and an electronic / electrical device on which the inductor is mounted.

Hereinafter, embodiments of the present invention will be described in detail. 1. Powdered magnetic core The powdered magnetic core 1 according to an embodiment of the present invention shown in FIG. 1 is a ring-shaped magnetic core whose appearance includes a powder of a crystalline magnetic material and a powder of an amorphous magnetic material. . The powder magnetic core 1 according to the present embodiment is manufactured by a manufacturing method including a molding process including press-molding a mixture containing these powders. As an example without limitation, the powder magnetic core 1 of this embodiment contains powder of crystalline magnetic material and powder of amorphous magnetic material with respect to other materials contained in the powder magnetic core 1 (there are materials of the same kind). In some cases, there are cases where the materials are different. (1) Powder of crystalline magnetic material Provide the powder of crystalline magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention, as long as the crystalline magnetic material is crystalline (by ordinary X-ray diffraction measurement) It is possible to obtain a diffraction spectrum with a clear peak to such an extent that the type of material can be specified), and it is a ferromagnetic body, especially a soft magnetic body, but the specific type is not limited. Specific examples of the crystalline magnetic material include Fe-Si-Cr-based alloys, Fe-Ni-based alloys, Fe-Co-based alloys, Fe-V-based alloys, Fe-Al-based alloys, Fe-Si-based alloys, and Fe -Si-Al based alloy, carbonyl iron and pure iron. The crystalline magnetic material may be composed of one type of material or may include a plurality of types of materials. The crystalline magnetic material that provides the powder of the crystalline magnetic material is preferably one or two or more materials selected from the group consisting of the above materials, and among them, Fe-Si-Cr-based alloys are more preferred, and more preferably It contains Fe-Si-Cr based alloy. Among Fe-Si-Cr-based alloy-based crystalline magnetic materials, materials that can reduce iron loss Pcv are relatively low. Therefore, even if the powder content of the crystalline magnetic material in the powder magnetic core 1 is increased compared to that of the crystalline magnetic material, The mass ratio of the sum of the content of the powder and the content of the powder of the amorphous magnetic material (also referred to as the "first mixing ratio" in this description), the iron loss Pcv of the inductor provided with the powder magnetic core 1 is not easy to rise high. The content of Si and the content of Cr in the Fe-Si-Cr-based alloy are not limited. As non-limiting examples, the content of Si is set to about 2 to 7 mass%, and the content of Cr is set to about 2 to 7 mass%. The shape of the powder of the crystalline magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention is not limited. The shape of the powder may be spherical or non-spherical. When it is non-spherical, it may be a shape with anisotropic shapes such as scaly, ellipsoidal, droplet, or needle, or an indefinite shape without special shape anisotropy. Examples of the amorphous powder include a case where a plurality of spherical powders are combined in contact with each other, or they are combined by being partially buried in other powders. This amorphous powder is easily observed in iron carbonyls. The shape of the powder may be a shape obtained at the stage of manufacturing the powder, or may be a shape obtained by performing secondary processing on the manufactured powder. Examples of the former shape include a spherical shape, an elliptical shape, a droplet shape, and a needle shape, and examples of the latter shape include a scaly shape. The particle diameter of the powder of the crystalline magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention is not limited. The particle size distribution of the crystalline magnetic material based on the volume-based particle size distribution from the small particle diameter side becomes the particle diameter of 50% (also referred to as "median particle diameter" in this specification) D ₅₀ C In some cases, it is preferably 15 μm or less. Compared with the powder of the amorphous magnetic material, the powder of the crystalline magnetic material is soft. Therefore, the powder of the crystalline magnetic material is more likely to deform inside the powder magnetic core 1. Therefore, the influence of the particle size on the characteristics of the powder magnetic core 1 is relatively low. The powder median particle diameter D ₅₀ A of the crystalline magnetic material is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 2 μm or less. The content of the powder of the crystalline magnetic material in the powder magnetic core 1 is an amount in which the first mixing ratio is 40% by mass or more and 90% by mass or less. When the first mixing ratio is 40% by mass or more and 90% by mass or less, the insulation and withstand voltage characteristics of the powder magnetic core 1 are improved as compared with a case where the powder magnetic core 1 is made of only an amorphous magnetic material. It is considered that the reason why the insulation withstand voltage characteristics are improved is that the powder magnetic core 1 contains powder of a crystalline magnetic material in the above range, and the insulation breakdown energy is dispersed throughout. From the viewpoint of stably improving the withstand voltage characteristics of the powder magnetic core 1, the first mixing ratio is more preferably 45% by mass or more and 85% by mass or less, and particularly preferably 50% by mass or more and 80% by mass or less. By setting the first mixing ratio within the above range, for example, a powder magnetic core 1 with good insulation and withstand voltage characteristics can be produced using an amorphous magnetic material having a D ₅₀ A of 3 μm or more and about 20 μm. The insulation withstand voltage of the powder magnetic core 1 is preferably 1.2 times or more, more preferably 1.25 times or more, the most preferably 1.25 times the insulation withstand voltage of the powder magnetic core containing only powder of amorphous magnetic material as the magnetic powder. 1.3 times or more. Here, the “magnetic powder” means a powder of a crystalline magnetic material and a powder of an amorphous magnetic material contained in the powder magnetic core 1. "Powder magnetic core containing only the powder of the above-mentioned amorphous magnetic material as magnetic powder" means that the same components and conditions are used except that all crystalline magnetic materials in the powder magnetic core are replaced with amorphous magnetic materials. Manufactured powder magnetic core. It is preferable that at least a part of the powder of the crystalline magnetic material includes a material subjected to surface insulation treatment, and it is more preferable that the powder of the crystalline magnetic material includes a material subjected to surface insulation treatment. When the surface of the crystalline magnetic material was subjected to surface insulation treatment, the tendency of the insulation resistance of the powder magnetic core 1 to be increased was observed. The type of the surface insulation treatment performed on the powder of the crystalline magnetic material is not limited. Examples thereof include phosphoric acid treatment, phosphate treatment, and oxidation treatment. (2) Powder of amorphous magnetic material Provides the amorphous magnetic material of the powder of the amorphous magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention as long as it is amorphous (according to general X-rays) Diffraction measurement cannot obtain a diffraction spectrum with a clear peak to such an extent that the type of material can be specified, and ferromagnetic materials, especially soft magnetic materials, are not limited to specific types. Specific examples of the amorphous magnetic material include Fe-Si-B-based alloys, Fe-PC-based alloys, and Co-Fe-Si-B-based alloys. The amorphous magnetic material may be composed of one type of material or may include a plurality of types of materials. The magnetic material constituting the powder of the amorphous magnetic material is preferably one or two or more materials selected from the group consisting of the foregoing materials. Among them, Fe-PC alloys are more preferred, and Fe is more preferred. -PC series alloy. Specific examples of the Fe-PC-based alloy include a composition formula represented by Fe _{100 atomic % -abcxyzt} Ni _a Sn _b Cr _c P _x C _y B _z Si _t and 0 atomic% ≦ a ≦ 10 atomic%, 0 atomic % ≦ b ≦ 3 atom%, 0 atom% ≦ c ≦ 6 atom%, 6.8 atom% ≦ x ≦ 13 atom%, 2.2 atom% ≦ y ≦ 13 atom%, 0 atom% ≦ z ≦ 9 atom%, 0 atom % ≦ t ≦ 7 atomic% Fe-based amorphous alloy. In the above composition formula, Ni, Sn, Cr, B, and Si are arbitrary addition elements. The addition amount a of Ni is preferably 0 atomic% or more and 6 atomic% or less, and more preferably 0 atomic% or more and 4 atomic% or less. The addition amount b of Sn is preferably 0 atomic% or more and 2 atomic% or less, and may be added in a range of 1 atomic% or more and 2 atomic% or less. The addition amount c of Cr is preferably 0 atomic% or more and 2 atomic% or less, and more preferably 1 atomic% or more and 2 atomic% or less. The addition amount x of P may be preferably 8.8 atomic% or more. The addition amount y of C is preferably 4 atomic% or more and 10 atomic% or less, and may be preferably 5.8 atomic% or more and 8.8 atomic% or less. The addition amount z of B is preferably 0 atomic% or more and 6 atomic% or less, and more preferably 0 atomic% or more and 2 atomic% or less. The addition amount t of Si is preferably 0 atomic% or more and 6 atomic% or less, and more preferably 0 atomic% or more and 2 atomic% or less. The shape of the powder of the amorphous magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention is not limited. Since the type of the powder is the same as that of the powder of the crystalline magnetic material, the description is omitted. Depending on the manufacturing method, the amorphous magnetic material may be easily formed into a spherical shape or an elliptical shape. In addition, in general, an amorphous magnetic material is harder than a crystalline magnetic material. Therefore, it is preferable to make the crystalline magnetic material non-spherical and to easily deform it during press molding. The shape of the powder of the amorphous magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention may be a shape obtained at the stage of manufacturing the powder, or may be obtained by performing secondary processing on the manufactured powder. Its shape. Examples of the former shape include a spherical shape, an oval shape, and a needle shape, and examples of the latter shape include a scaly shape. The particle diameter of the powder of the amorphous magnetic material contained in the powder magnetic core 1 according to an embodiment of the present invention is preferably a case where the median diameter D ₅₀ A of the powder of the amorphous magnetic material is 50 μm or less. When the powder median diameter D ₅₀ A of the amorphous magnetic material is 50 μm or less, the insulation resistance of the powder magnetic core 1 may be easily increased and the iron loss Pcv may be reduced. From the viewpoint of stably improving the insulation resistance of the powder magnetic core 1 and reducing the iron loss Pcv, the powder median diameter D ₅₀ A of the amorphous magnetic material is preferably less than 20 μm. It is more preferably 10 μm or less, and more preferably 7 μm or less, and particularly preferably 5 μm or less. (3) Bonding component The powder magnetic core 1 may also contain a bonding component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to other materials contained in the powder magnetic core 1. As long as the binding component is a powder of a crystalline magnetic material and a powder of an amorphous magnetic material that contributes to the fixation of the powder magnetic core 1 of this embodiment (these powders may be collectively referred to in this specification "Magnetic powder"), its composition is not limited. Examples of the material constituting the binding component include organic materials and inorganic materials such as resin materials and thermal decomposition residues of resin materials (these are collectively referred to as "resin-based components" in this specification). Examples of the resin material include acrylic resin, silicone resin, epoxy resin, phenol resin, urea resin, and melamine resin. Examples of the binding component containing an inorganic-based material include glass-based materials such as water glass. The binding component may be composed of one material or may include a plurality of materials. The binding component may be a mixture of organic materials and inorganic materials. As the binding component, an insulating material is usually used. This can improve the insulation properties of the powder magnetic core 1. 2. Manufacturing method of powdered magnetic core The manufacturing method of the powdered magnetic core 1 according to one embodiment of the present invention is not particularly limited, but if the manufacturing method described below is used, the powdered powder can be manufactured more efficiently. Magnetic core 1. The method for manufacturing a powder magnetic core 1 according to an embodiment of the present invention includes a forming step described below, and may further include a heat treatment step. (1) Molding step First, a mixture containing a magnetic powder and a component for providing a binding component in the powder magnetic core 1 is prepared. The ingredients (also referred to as "adhesive ingredients" in this specification) that provide the binding component may be either the binding component itself or a material different from the binding component. As a specific example of the latter, a case where the adhesive component is a resin material and the binding component is a thermal decomposition residue thereof can be cited. A molded article can be obtained by a molding process including press molding of the mixture. The pressing conditions are not limited, and are appropriately determined based on the composition of the adhesive component and the like. For example, in the case where the adhesive component contains a thermosetting resin, it is preferred to heat the resin while applying pressure while curing the resin in the mold. On the other hand, in the case of compression molding, although the pressing force is high, heating is not an essential condition, and it becomes short-term pressure. Hereinafter, the case where the mixture is granulated powder and compression-molded will be described in detail. Since the granulated powder is excellent in handleability, it is possible to improve workability in a compression molding step having a short molding time and excellent productivity. (1-1) Granulated powder Granulated powder contains a magnetic powder and a binder component. The content of the binder component in the granulated powder is not particularly limited. When the content is too low, it is difficult for the binder component to hold the magnetic powder. In addition, when the content of the binder component is too low, in the powder magnetic core 1 obtained through the heat treatment step, it is difficult for the binding component composed of the thermal decomposition residue of the binder component to make the plurality of magnetic powders and other Powder insulation. On the other hand, when the content of the binder component is too high, the content of the binding component contained in the powder magnetic core 1 obtained through the heat treatment step tends to be high. When the content of the binding component in the powder magnetic core 1 becomes high, the magnetic characteristics of the powder magnetic core 1 tend to decrease. Therefore, the content of the binder component in the granulated powder is preferably set to an amount of 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 of a decrease in magnetic characteristics of the powder magnetic core 1, the content of the binder component in the granulated powder is preferably 1.0% by mass or more relative to the entire granulated powder. The amount of 3.5% by mass or less is more preferably an amount of 1.2% by mass or more and 3.0% by mass or less. The granulated powder may contain materials other than the magnetic powder and the binder component described above. Examples of such a material include a lubricant, a silane coupling agent, and an insulating filler. When a lubricant is contained, the kind is not specifically limited. It can 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 vaporizes during the heat treatment step and hardly remains in the powder magnetic core 1. The method for producing the granulated powder is not particularly limited. The ingredients that provide the above granulated powder can be directly kneaded, and the obtained kneaded product can be pulverized by a known method to obtain a granulated powder, or a dispersion medium can be added to the above ingredients (including water as an example One example), the slurry is dried and pulverized to obtain granulated powder. It can also be sieved or classified after crushing to control the particle size distribution of the granulated powder. As an example of a method for obtaining granulated powder using the above slurry, a method using a spray dryer is mentioned. As shown in FIG. 2, a rotor 201 is provided in the spray dryer device 200, and slurry S is injected from the upper part of the spray dryer device 200 toward the rotor 201. The rotor 201 rotates at a specific rotation speed, and sprays the slurry S in a droplet shape using a centrifugal force in a chamber inside the spray dryer device 200. Furthermore, hot air is introduced into the chamber inside the spray dryer apparatus 200, whereby the dispersion medium (water) contained in the droplet-shaped slurry S is volatilized while maintaining the droplet shape. As a result, the granulated powder P is formed from the slurry S. The granulated powder P was recovered from the lower part of the spray dryer apparatus 200. The parameters such as the rotation speed of the rotor 201, the temperature of the hot air introduced into the spray dryer device 200, and the temperature of the lower part of the chamber may be appropriately set. As specific examples of the setting range of these parameters, 4000-8000 rpm can be cited as the rotation speed of the rotor 201, 130-170 ° C can be cited as the temperature of the hot air introduced into the spray dryer device 200, and the temperature at the lower part of the chamber can be cited 80 ～ 90 ℃. In addition, the atmosphere in the chamber and its pressure may be appropriately set. As an example, an air (air) atmosphere is used in the chamber, and the pressure is set to 2 mmH ₂ O (approximately 0.02 kPa) as a differential pressure from the atmospheric pressure. The particle size distribution of the obtained granulated powder P can also be further controlled by sieving and the like. (1-2) Pressing conditions There are no particular restrictions on the pressing conditions during compression molding. It may be appropriately set in consideration of the composition of the granulated powder, the shape of the molded product, and the like. When the pressure applied during compression molding of the granulated powder is too low, the mechanical strength of the molded product decreases. Therefore, problems such as a decrease in the rationality of the molded product and a reduction in the mechanical strength of the powder magnetic core 1 obtained from the molded product are likely to occur. In addition, the magnetic properties of the powder magnetic core 1 may be reduced or the insulation may be reduced. On the other hand, when the pressure applied during the compression molding of the granulated powder is too high, it becomes difficult to produce a mold capable of withstanding the pressure. From the viewpoint of more stably reducing the possibility that the compression and pressing step may adversely affect the mechanical characteristics or magnetic characteristics of the powder magnetic core 1, and it is easy to mass-produce industrially, the pressure applied during compression molding of the granulated powder is smaller It is more preferably 0.3 GPa or more and 2 GPa or less, more preferably 0.5 GPa or more and 2 GPa or less, and particularly preferably 0.8 GPa or more and 2 GPa or less. During compression molding, pressure can be applied while heating, or pressure can be applied at normal temperature. (2) Heat treatment step The formed article obtained by the forming step may be the powder magnetic core 1 of this embodiment, or the powder article magnetic core 1 may be obtained by performing a heat treatment step on the formed article as described below. In the heat treatment step, the formed article obtained by the above forming step is heated, and the magnetic characteristics are adjusted by correcting the distance between the magnetic powders, and the strain imparted to the magnetic powder in the forming step is relaxed. The magnetic characteristics are adjusted to obtain a powder magnetic core 1. The heat treatment step is to adjust the magnetic characteristics of the powder magnetic core 1 as described above. Therefore, heat treatment conditions such as a heat treatment temperature are set so that the magnetic characteristics of the powder magnetic core 1 become the best. As an example of a method for setting the heat treatment conditions, the heating temperature of the molded article is changed, and other conditions such as a heating rate and a holding time at the heating temperature are fixed. The evaluation criteria of the magnetic characteristics of the powder magnetic core 1 when the heat treatment conditions are set are not particularly limited. As a specific example of the evaluation item, the iron loss Pcv of the powder magnetic core 1 may be mentioned. In this case, the heating temperature of the molded article may be set so that the iron loss Pcv of the powder magnetic core 1 becomes the lowest. The measurement conditions of the iron loss Pcv are appropriately set. As an example, the conditions are set to a frequency of 100 Hz and an effective maximum magnetic flux density Bm of 100 mT. The atmosphere during the heat treatment is not particularly limited. In the case of an oxidizing atmosphere, the possibility that the thermal decomposition of the binder component may proceed excessively or that the magnetic powder may be oxidized is increased. Therefore, it is preferably in an inert atmosphere such as nitrogen or argon or a reducing atmosphere such as hydrogen Perform heat treatment. 3. Inductor, electronic and electrical equipment An inductor according to an embodiment of the present invention includes the powder magnetic core 1 according to an embodiment of the present invention described above, a coil, and connection terminals connected to respective ends of the coil. Here, at least a part of the powder magnetic core 1 is arranged so as to be located in an induced magnetic field generated by the current when a current is passed to the coil via the connection terminal. Since the inductor according to one embodiment of the present invention includes the powder magnetic core 1 according to the embodiment of the present invention, it has excellent insulation withstand voltage characteristics, and it is difficult to increase iron loss even at high frequencies. Therefore, compared with the inductor of the prior art, it can be miniaturized. As an example of such an inductor, the toroidal coil 10 shown in FIG. 3 is mentioned. The toroidal coil 10 includes a coil 2 a formed by winding a conductive wire 2 on a ring-shaped powder magnetic core (ring-shaped magnetic core) 1. The ends 2d, 2e of the coil 2a may be defined in a portion of the conductive wire located between the coil 2a including the wound covered conductive wire 2 and the ends 2b, 2c of the covered conductive wire 2. As described above, in the inductor of the present embodiment, the members constituting the coils and the members constituting the connection terminals may be constituted by the same member. As another example of the inductor according to an embodiment of the present invention, a coil-embedded inductor 20 shown in FIG. 4 may be mentioned. The coil-embedded inductor 20 may be formed in a small wafer shape of several mm square, and may include a powder magnetic core 21 having a box shape, and a coil portion 22c covered with a conductive wire 22 may be embedded therein. The end portions 22 a and 22 b of the covered conductive wire 22 are located on the surface of the powder magnetic core 21 and are exposed. A part of the surface of the powder magnetic core 21 is covered by the connection ends 23a, 23b which 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 line 22, and the connection end portion 23 b is electrically connected to the end portion 22 b of the covered conductive line 22. In the coil-embedded inductor 20 shown in FIG. 4, the end portion 22a of the covered conductive wire 22 is covered by the connection end portion 23a, and the end portion 22b of the covered conductive wire 22 is covered by the connection end portion 23b. The method of embedding the coil portion 22c of the conductive wire 22 into the powder magnetic core 21 is not limited. The member wound with the covered conductive wire 22 may be arranged in a mold, and a mixture (granulated powder) containing a magnetic powder may be supplied into the mold and press-molded. Alternatively, a plurality of members obtained by pre-forming a mixture (granulated powder) containing a magnetic powder may be prepared, and these members may be combined, and the covered conductive wire 22 may be arranged in the space formed at this time to obtain assembly. This assembly is press-molded. The material of the covered conductive wire 22 including the coil portion 22c is not limited. For example, a copper alloy is mentioned. The coil portion 22c may be a flat winding coil. The material of the connection ends 23a and 23b is also not limited. From the viewpoint of excellent productivity, it is preferable to include a metallized layer formed of 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 one in which the above-described inductor according to one embodiment of the present invention is mounted, and is connected to a substrate using the connection terminal. An electronic / electrical device according to an embodiment of the present invention is equipped with an inductor according to an embodiment of the present invention. Therefore, even if a high voltage or a high-frequency signal is applied to the device, a reduction in the function of the inductor is unlikely to occur. Or failure caused by heat, the miniaturization of the machine is also easier. The embodiments described above are described in order to make the present invention easier to understand, and are not described in order to limit 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, the present invention will be described more specifically with examples and the like, but the scope of the present invention is not limited by these examples and the like. (Example 1) (1) Preparation of Fe-based amorphous alloy powder to become the _{rest of} Fe Ni _{5 to 7 atomic %} Cr _{2 to 4 atomic %} P _{10 to 13 atomic %} C _{5 to 6 atomic %} B _{2 to 4 The atomic %} composition was used to weigh the raw materials, and a powder (amorphous powder) of an amorphous magnetic material was produced using a water atomization method. The "Microtrac particle size distribution measuring device MT3300EX" manufactured by Nikkiso Co., Ltd. was used to measure the particle size distribution of the obtained amorphous magnetic material powder in the form of volume distribution. The particle size (median particle size) D ₅₀ A whose cumulative particle size distribution from the small particle size side in the volume-based particle size distribution becomes 50% is 5 μm. In addition, Fe-Si-Cr-based alloys are prepared as powders of the crystalline magnetic material. Specifically, the Fe-Si-Cr-based alloy is prepared with a content of 6 to 7 mass%, a content of Cr of 3 to 4 mass%, and Fe and Powder with an alloy of unavoidable impurities and a median diameter D ₅₀ C of 2 μm. (2) Preparation of granulated powder The powder of the amorphous magnetic material and the powder of the crystalline magnetic material were mixed so as to have a 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 bonding material containing an acrylic resin or a phenol resin, and 0 to 0.5 parts by mass of a lubricant containing zinc stearate are mixed into water as a solvent to obtain a slurry. . The obtained slurry was granulated using the spray dryer apparatus 200 shown in FIG. 2 under the above-mentioned conditions to obtain granulated powder. (3) Compression molding Fill the obtained granulated powder into a mold and press-mold at a surface pressure of 0.5 to 1.5 GPa to obtain a ring shape having an outer diameter of 20 mm × internal diameter of 12 mm × thickness of 3 mm. Shaped body. (4) Heat treatment A heat treatment is performed to obtain a toroidal magnetic core including a powder magnetic core. In the heat treatment, the obtained formed body is placed in a furnace in a nitrogen flow atmosphere, and the temperature in the furnace is from room temperature (23 ° C) to The heating rate at 10 ° C / min is heated to 200 to 400 ° C, which is the optimal heat treatment temperature of the magnetic core, and is maintained at this temperature for 1 hour, and then cooled to room temperature in the furnace. Toroidal cores having different first mixing ratios shown in Table 1 below were produced, and the core density, insulation resistance, insulation withstand voltage, magnetic permeability, and iron loss Pcv were measured by the following measurement methods. (Experimental example 1) Measurement of insulation withstand voltage A measurement device of "TOS5051A" manufactured by Kikusui was used as a measuring device. A ring-shaped magnetic core as a sample was held by parallel plate electrodes. ) Apply an applied voltage. Calculate the voltage at which insulation breakdown occurs as the insulation withstand voltage. Regarding the insulation withstand voltage values of Examples 1-2 to 1-8 measured as described above, the ring-shaped magnetic core of Example 1-1 using powder containing only an amorphous magnetic material as a magnetic powder was obtained. Insulation withstand voltage ratio (100% based on amorphous) when the insulation withstand voltage value is a reference (100%), and the toroidal magnetic core of Example 1-8 using a powder containing only a crystalline magnetic material as a magnetic powder Insulation withstand voltage ratio (100% based on crystallinity) when the insulation withstand voltage is the standard (100%). (Experimental example 2) Measurement of insulation resistance A high-resistance measuring device "4339B" of former Agilent (now Keysight) was used as a measuring device, and was measured by a two-terminal method at an applied voltage of 20 V. (Test example 3) Measurement of magnetic core density ρ The size and weight of the toroidal magnetic core manufactured in Example 1 were measured, and the density ρ (unit: g / cc) of each toroidal magnetic core was calculated based on these values. . (Experimental Example 4) Measurement of Permeability For a toroidal coil obtained by winding a coated copper wire on the toroidal magnetic core manufactured in Example 1 40 times on the primary side and 10 times on the secondary side, Using an impedance analyzer ("4192A" manufactured by HP), the initial permeability μ0 was measured at 100 kHz. (Experimental example 5) Measurement of iron loss Pcv For a toroidal coil obtained by winding a coated copper wire on the toroidal core made in Example 1 15 times on the primary side and 10 times on the secondary side, Using a BH analyzer ("SY-8217" manufactured by Iwasaki Telecommunications Corporation), the iron loss Pcv was measured at a measurement frequency of 2 MHz with the effective maximum magnetic flux density Bm set to 15 mT (unit: kW / m ³ ) . Table 1 shows the results measured by the methods of Test Examples 1 to 5 above. [Table 1] FIG. 5 is a graph showing the dependence of the insulation withstand voltage on the first mixing ratio in Example 1. FIG. As shown in the graph of the insulation withstand voltage of the figure, in Example 1, by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, the insulation is compared with the case where each magnetic powder is used alone. Improved withstand voltage characteristics. That is, by mixing the different magnetic powders described above, the effect of increasing the insulation withstand voltage value of the powder magnetic core is obtained synergistically. In Example 1, the insulation withstand voltage value increased sharply from the vicinity of the first mixing ratio of 30% to 40% by mass, and the insulation withstand voltage ratio reached 120% or more in the range of 40% to 70% by mass, at 50% by mass. In the range of% to 70% by mass, the insulation withstand voltage ratio reaches 130% or more, and the value of the insulation withstand voltage ratio based on the powdered monomer of the amorphous magnetic material of Example 1-1 (100%) is increased by 30%. the above. (Example 2) The particle diameter of the powder of the amorphous magnetic material, the surface treatment of the powder of the crystalline magnetic material, and the magnetic powder having a particle diameter different from that of the magnetic powder used in Example 1 were used to be the same as in Example 1. In this way, a toroidal magnetic core including a powder magnetic core is obtained. Specifically, as a powder of an amorphous magnetic material, an Fe-based amorphous alloy powder having the same composition as in Example 1 and a median diameter D ₅₀ A of 15 μm was produced. In addition, the powder of the amorphous magnetic material used in Example 2 was produced by the atomization method which continuously performed gas atomization and water atomization. As a powder of a crystalline magnetic material, an Fe-Si-Cr-based alloy is prepared. Specifically, the content of Si is 6 to 7 mass%, the content of Cr is 3 to 4 mass%, and the rest contains Fe and is unavoidable. A powder made of an alloy of impurities and having a median diameter D ₅₀ C of 4 μm. As the powder of the crystalline magnetic material, a phosphate-based surface insulation treatment is used. The pressure of the press forming is 0.5 to 1.5 GPa, and in the heat treatment, it is heated at 200 to 400 ° C for one hour in a nitrogen atmosphere. Toroidal cores with different first mixing ratios shown in Table 2 below were fabricated, and the insulation withstand voltage, insulation resistance, core density, magnetic permeability, and iron loss Pcv were measured. (Test Examples 1 to 5) In the same manner as in Example 1, the measurement of the insulation withstand voltage, the measurement of the insulation resistance, the measurement of the magnetic core density ρ, the measurement of the magnetic permeability, and the measurement of the iron loss Pcv were performed. Calculate the insulation withstand voltage ratio (amorphous 100% basis) when the insulation withstand voltage value of the toroidal magnetic core of Example 2-1 containing only powder of amorphous magnetic material is used as the basis (100%), And the insulation withstand voltage ratio (100% crystalline basis) when the insulation withstand voltage value of the toroidal magnetic core of Example 2-7 using powder containing only crystalline magnetic material as the magnetic powder was based on (100%). Regarding the permeability, in addition to the initial permeability μ0, the relative permeability μ5500 when a DC applied magnetic field of 5500 A / m was superimposed on a toroidal core at a frequency of 100 kHz was also measured. The measurement results are shown in Table 2. [Table 2] FIG. 6 is a graph showing the dependence of the insulation withstand voltage on the first mixing ratio in Example 2. FIG. As shown in the graph of the insulation withstand voltage of FIG. 6, in Example 2, the same as Example 1, by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, and using the powder of each powder alone In comparison, the insulation withstand voltage characteristics were improved, and a synergistic effect was confirmed. In Example 2, the powder with an insulation withstand voltage higher than that of the amorphous magnetic material was near the first mixing ratio of 40% by mass, and the insulation withstand voltage ratio reached 180% or more in the range of 70% to 90% by mass. Based on the powder monomer of the amorphous magnetic material of Example 2-6, the value of the insulation withstand voltage ratio (100%) was increased by more than 80%. FIG. 7 is a graph showing the dependence of the insulation withstand voltage on the first mixing ratio in Examples 1 and 2. FIG. From the results of this figure, it can be seen that by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, a powder magnetic core having a higher insulation withstand voltage can be obtained compared with the case where each powder is used alone. That is, FIG. 7 shows that it is expected that the mixing ratio of the powder of the crystalline magnetic material and the powder of the amorphous magnetic material contained in the powder magnetic core is beyond the expected synergistic effect, that is, the insulation is obtained. Powder magnetic core with excellent withstand voltage characteristics. FIG. 8 is a graph showing insulation withstand voltage ratios at respective first mixing ratios based on powdered monomers of an amorphous magnetic material in Examples 1 and 2, and FIG. 9 shows Example 1 and implementation The graph of the insulation withstand voltage ratio of each of the first mixing ratios based on the powder monomer of the crystalline material in Example 2. From the results of FIGS. 5 to 9, it can be seen that the effect of increasing the value of the insulation withstand voltage is by appropriately adjusting the median diameter D ₅₀ A of the amorphous magnetic material, and setting the first mixing ratio to 40% by mass. It can be used stably within the range of 90 masses or less. In addition, by setting the first mixing ratio to 50 to 70% by mass, the insulation withstand voltage of the piezoelectric core can be improved regardless of whether the median diameter D ₅₀ A of the amorphous magnetic material is large or small. characteristic. Furthermore, as can be seen from FIG. 9, if the first mixing ratio (50 to 70% by mass) as described above is obtained, a powder magnetic core containing only crystalline material powder as the magnetic powder (100%) can be obtained. In this case, the value of the insulation withstand voltage ratio is 110% or more, or 125% or more of the powder magnetic core. 10 to 12 are graphs showing the dependence of the insulation resistance, the core density, and the magnetic permeability on the first mixing ratio in Example 1 in order. 13 to 15 are graphs showing the dependence of the insulation withstand voltage, insulation resistance, magnetic core density, and magnetic permeability on the first mixing ratio in Example 2. As shown in Tables 1 and 2 and FIGS. 5 to 15, the excellent powder magnetic core obtained by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material can not only improve the withstand voltage characteristics, In addition, the insulation withstand voltage can be increased in a state where the iron loss Pcv is hardly increased, thereby providing a good inductor. According to the present invention, it is possible to obtain a powder magnetic core that provides an inductor with excellent insulation and withstand voltage characteristics and reduced iron loss. According to this embodiment, it is confirmed that the powder magnetic core exceeds the crystalline content contained in the powder magnetic core. Expected degree of mixing ratio of powder of magnetic material and powder of amorphous magnetic material. [Industrial Applicability] The inductor provided with the powder magnetic core of the present invention can be preferably used as a component of a booster circuit, a component of a power generation / transformation device, a transformer, or a transformer. Components such as coils.

1‧‧‧Pressed Powder Core (Ring Core)

2‧‧‧ covered conductive wire

2a‧‧‧coil

2b, 2c‧‧‧ Cover the ends of conductive wire 2

2d, 2e‧‧‧End of coil 2a

10‧‧‧ Toroid

20‧‧‧coil embedded inductor

21‧‧‧Pressed powder magnetic core

22‧‧‧ covered conductive wire

22a, 22b‧‧‧End

22c‧‧‧Coil Department

23a, 23b ‧‧‧ connecting end

200‧‧‧ spray dryer device

201‧‧‧rotor

P‧‧‧Granulated powder

S‧‧‧ slurry

FIG. 1 is a perspective view conceptually showing the shape of a powder magnetic core according to an embodiment of the present invention. FIG. 2 is a diagram conceptually showing a spray dryer device used in an example of a method for producing granulated powder and its operation. FIG. 3 is a perspective view conceptually showing the shape of a toroidal coil as one type of an inductor including a powder magnetic core according to an embodiment of the present invention. FIG. 4 is a perspective view conceptually showing the shape of a coil-embedded inductor, which is one type of inductor including a powder magnetic core according to an embodiment of the present invention. FIG. 5 is a graph showing the dependence of the insulation withstand voltage on the first mixing ratio in Example 1. FIG. FIG. 6 is a graph showing the dependence of the insulation withstand voltage on the first mixing ratio in Example 2. FIG. FIG. 7 is a graph showing the dependence of the insulation withstand voltage on the first mixing ratio in Examples 1 and 2. FIG. FIG. 8 is a graph showing insulation withstand voltage ratios at respective first mixing ratios based on powdered monomers of amorphous magnetic materials in Examples 1 and 2. FIG. FIG. 9 is a graph showing insulation withstand voltage ratios at respective first mixing ratios based on powdered monomers of crystalline magnetic materials in Examples 1 and 2. FIG. FIG. 10 is a graph showing the dependence of the insulation resistance on the first mixing ratio in Example 1. FIG. FIG. 11 is a graph showing the dependence of the core density on the first mixing ratio in Example 1. FIG. FIG. 12 is a graph showing the dependence of the magnetic permeability on the first mixing ratio in Example 1. FIG. FIG. 13 is a graph showing the dependence of the insulation resistance on the first mixing ratio in Example 2. FIG. FIG. 14 is a graph showing the dependence of the core density on the first mixing ratio in Example 2. FIG. FIG. 15 is a graph showing the dependence of the magnetic permeability on the first mixing ratio in Example 2. FIG.

Claims (15)

A powder magnetic core is a powder containing a crystalline magnetic material and an amorphous magnetic material. The content of the powder of the crystalline magnetic material relative to the content of the powder of the crystalline magnetic material is the same as that of the amorphous The mass ratio of the sum of the content of the powder of the magnetic material, that is, the first mixing ratio is 40% by mass or more and 90% by mass or less, and the amorphous magnetic material contains a material selected from the group consisting of Fe-Si-B alloys and Fe-PC systems. One or two or more materials in the group consisting of alloys and Co-Fe-Si-B alloys. The powder magnetic core according to claim 1, wherein the first mixing ratio is 50% by mass or more and 70% by mass or less. The powder magnetic core according to claim 1 or 2, wherein the crystalline magnetic material includes a material selected from the group consisting of Fe-Si-Cr-based alloy, Fe-Ni-based alloy, Fe-Co-based alloy, Fe-V-based alloy, and Fe-Al One or two or more kinds of materials in a group consisting of alloys, Fe-Si alloys, Fe-Si-Al alloys, carbonyl iron, and pure iron. The powder magnetic core according to claim 1 or 2, wherein the crystalline magnetic material includes an Fe-Si-Cr-based alloy. The powder magnetic core according to claim 1 or 2, wherein the amorphous magnetic material includes a Fe-P-C series alloy. For example, the powder magnetic core of claim 1 or 2 contains a binding component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to other materials contained in the powder magnetic core. The powder magnetic core according to claim 6, wherein the binding component includes a resin material-based component. A method for manufacturing a powder magnetic core, which is the method for manufacturing a powder magnetic core as claimed in claim 7, and is provided with a forming step which obtains a shaped article by a forming process including pressure forming of a mixture, as described above. The mixture includes a powder of the crystalline magnetic material, a powder of the amorphous magnetic material, and a binder component containing the resin material. The method for manufacturing a powder magnetic core according to claim 8, wherein the above-mentioned molded article obtained through the above-mentioned forming step is the above-mentioned powder magnetic core. The method for manufacturing a powder magnetic core according to claim 8, comprising a heat treatment step of obtaining the powder magnetic core by heat-treating the molded article obtained by the above-mentioned forming step. An inductor includes a powder magnetic core, a coil, and connection terminals connected to each end of the coil as described in claim 1 or 2, and at least a part of the powder magnetic core is located at the connection terminal. When a current flows through the coil, it is arranged in an induced magnetic field generated by the current. An electronic / electrical device including an inductor as claimed in claim 11, and the inductor is connected to a substrate using the connection terminal. A powder magnetic core is a powder containing a crystalline magnetic material and an amorphous magnetic material. The content of the powder of the crystalline magnetic material relative to the content of the powder of the crystalline magnetic material is the same as that of the amorphous material. The mass ratio of the sum of the contents of the powders of the magnetic material, that is, the first mixing ratio is 40% by mass or more and 90% by mass or less, and the insulation withstand voltage value of the powder magnetic core is such that only the amorphous magnetic material is contained. When the powder is used as a magnetic powder, the insulation voltage resistance value of the powder magnetic core is 120% or more. A powder magnetic core is a powder containing a crystalline magnetic material and an amorphous magnetic material. The content of the powder of the crystalline magnetic material relative to the content of the powder of the crystalline magnetic material is the same as that of the amorphous material. The mass ratio of the sum of the content of the powder of the magnetic material, that is, the first mixing ratio is 40% by mass or more and 90% by mass or less, and the insulation withstand voltage of the powder magnetic core is equal to the powder containing only the crystalline magnetic material When the insulation withstand voltage value of a powder magnetic core as a magnetic powder is based on 100%, it is 110% or more. A powder magnetic core is a powder containing a crystalline magnetic material and an amorphous magnetic material. The content of the powder of the crystalline magnetic material relative to the content of the powder of the crystalline magnetic material is the same as that of the amorphous material. The mass ratio of the total content of the powder of the magnetic material, that is, the first mixing ratio is 40% by mass or more and 90% by mass or less, and the powder of the crystalline magnetic material includes a material subjected to an insulation treatment.