CN1700369B - High-frequency magnetic core and inductance element using the high-frequency magnetic core - Google Patents

Abstract

A high-frequency magnetic core (1) which is a molded body obtained by molding a mixture of soft magnetic metallic glass powder and a binder of 10% by mass or less. The powder has an alloy composition represented by the following general formula: (Fe _1-a Co _a ) _100-xyzqr (M _1-p M' _p ) _{x Ty} B _z C _q Al _r (0≤a≤0.50, 0≤ p ≤ 0.5, 2 atomic % ≤ x ≤ 5 atomic %, 8 atomic % ≤ y ≤ 12 atomic %, 12 atomic % ≤ z ≤ 17 atomic %, 0.1 atomic % ≤ q ≤ 1.0 atomic %, 0.2 atomic % ≤ r ≤ 2.0 atomic % and 25≤(x+y+z+q+r)≤30, M is at least one selected from Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W, and M' is At least one selected from Zn, Sn, and R (R is at least one selected from rare earth metals including Y), and T is at least one selected from Si and P). An inductive element (101, 102) is formed by a core and a coil (3).

Description

High-frequency magnetic core and inductance element using the high-frequency magnetic core

This application claims priority from Japanese Patent Application JP-2004-146595, the disclosure of which is incorporated herein by reference.

technical field

The invention relates to a high-frequency magnetic core mainly using soft magnetic materials and an inductance element using the high-frequency magnetic core.

Background technique

So far, soft ferrite, high-silicon steel, amorphous metal, powder core, etc. have been mainly used as materials for high-frequency magnetic cores. The reason for using the above materials is as follows. In the case of soft ferrite, the material itself has a high specific resistance. In the case of other metal materials, although the material itself has low specific resistance, the material can be formed into flakes or powders to reduce eddy currents. The above-mentioned materials are selected and used according to the working frequency or intended use. Therefore, the reason is concluded that materials with high specific resistance, such as soft ferrite, have low saturation magnetic flux density, while materials with high saturation magnetic flux density, such as high silicon steel, have low specific resistance. Therefore, a magnetic material having a high saturation magnetic flux density and a high specific resistance cannot be provided so far.

While the following remarkable progress has been made in recent years in downsizing and improving the functions of various electronic devices, inductance elements such as coils and transformers need to be downsized and have inductance at large currents. In order to meet the above demands, it is necessary to simultaneously improve the saturation magnetic flux density and high-frequency loss performance of the core. Additionally, increased coil or transformer heat generation due to copper loss due to winding coil resistance. Therefore, there is a need to provide a method for suppressing temperature rise.

If it is soft ferrite, the saturation magnetic flux density can be improved, but it cannot be substantially improved in practice. If it is high silicon steel or amorphous metal, the material itself has a high saturation magnetic flux density. However, in order to accommodate the high frequency band, the material must be formed into thin sheets when the frequency band is higher. Using a multilayer core of such materials reduces the space factor, which can lead to a reduction in the saturation magnetic flux density.

In addition, if it is a powder core, high specific resistance can be obtained by inserting an insulating material between fine powder particles and a high saturation magnetic flux density can be obtained by high-density molding. However, this presents some difficult problems. That is, a method of improving the saturation magnetism of the soft magnetic powder used therefor and a method of forming a high-density molded body while maintaining insulation between powder particles have not been established so far.

In order to correct the above problems, especially the difficulty in obtaining a magnetic material having a saturation magnetic flux density and a high specific resistance, a method of preparing a powder core and producing the powder core in which metallic glass powder is used as a soft magnetic powder, mixed with an insulating material, and formed into a molded body at a temperature not lower than normal temperature to obtain a soft magnetic material with high magnetic permeability and good frequency properties (see Japanese Unexamined Patent Application Publication (JP-A) -2001-189211, hereinafter referred to as Patent Document 1).

Here, there are many kinds of alloy compositions collectively called metallic glasses. However, the alloy composition used as a soft magnetic material is limited to Fe-based alloys, which are generally divided into FePCBSiGa alloy composition and FeSiBM (M is a transition metal) alloy composition.

Patent Document 1 uses the former, that is, an alloy composed of FePcBSiGa alloy, and discloses that by using this soft magnetic material, excellent magnetic properties that can achieve high specific resistance and high saturation magnetic flux density can be obtained. Note here that the latter is FeSiBM alloy The composition is also disclosed (see Japanese Unexamined Patent Application Publication (JP-A)-2002-194514 and H11-131199, hereinafter referred to as Patent Documents 2 and 3, respectively). In addition, use of a soft magnetic material as a core is also disclosed (see Japanese Unexamined Patent Application Publication (JP-A)-H11-74111, hereinafter referred to as Patent Document 4).

On the other hand, it has been disclosed that winding coils and metal powders form a monolithic structure of reduced size in order to improve DC superposition properties (see Japanese Unexamined Patent Application Publication (JP-A)-H04-286305 and 2002-305108, hereinafter respectively referred to as as Patent Documents 5 and 6).

In the case where the above-mentioned soft magnetic material is used as a high-frequency core, for example, in the case of the FePCBSiGa alloy composition disclosed in Patent Document 1, magnetic properties including high magnetic permeability and relatively excellent frequency properties can be obtained. In this case, however, expensive metals such as Ga need to be used. This causes a problem that the cost of the material itself is high, and thus the promotion of industrial applications is inhibited.

On the other hand, in the FeSiBM alloy composition disclosed in Patent Documents 2 and 3 and considered in Patent Document 4 to be applied to a core, the material itself has excellent economical efficiency. However, in these patent documents, techniques for obtaining high specific resistance and high magnetic flux density are not shown (this is presumably because a method of forming a powder and a method of forming a molded body suitable for an alloy composition have not been found, and these method is suitable for the alloy composition). Therefore, at present, it is difficult to use materials for high-frequency magnetic cores and inductance elements using the high-frequency magnetic cores.

Patent Documents 5 and 6 disclose reduction in coil size. However, loss reduction is not sufficient because existing soft magnetic metal materials are used.

Contents of the invention

The object of the present invention is to provide an inexpensive high-frequency magnetic core made of soft magnetic material having high saturation magnetic flux density and high specific resistance and an inductance element using the high-frequency magnetic core.

According to an aspect of the present invention, there is provided a high-frequency magnetic core comprising a molded body obtained by molding a mixture of soft magnetic metallic glass powder and a binder, in mass ratio to the soft magnetic metallic glass powder, The binder content is 10% or less by mass, and the soft magnetic metallic glass powder has an alloy composition represented by the following general formula: (Fe _1-a Co _a ) _100-xyzqr (M _1-p M' _p ) _x T _y B _z C _q Al _r , 0 ≤ a ≤ 0.50, 0 ≤ p ≤ 0.5, 2 at % ≤ x ≤ 5 at %, 8 at % ≤ y ≤ 12 at %, 12 at % ≤ z ≤ 17 atomic %, 0.1 atomic %≤q≤1.0 atomic %, 0.2 atomic %≤r≤2.0 atomic % and 25≤(x+y+z+q+r)≤30, M is selected from Zr, Nb, Ta, Hf , at least one of Mo, Ti, V, Cr and W, M' is at least one selected from Zn, Sn and R, R is at least one element selected from rare earth metals including Y, and T is At least one selected from Si and P.

According to another aspect of the present invention, an inductance element is provided, which includes a high-frequency magnetic core and at least one coil wound around the high-frequency magnetic core.

According to yet another aspect of the present invention, an inductance element is provided, which includes a high-frequency magnetic core and at least one coil wound around the high-frequency magnetic core.

Brief description of the drawings

1 is an external perspective view showing the basic structure of a high frequency magnetic core according to one embodiment of the present invention;

Fig. 2 is an external perspective view of an inductance element including a high-frequency magnetic core shown in Fig. 1 and a coil surrounding the high-frequency magnetic core;

3 is an external perspective view of the basic structure of a high frequency magnetic core according to another embodiment of the present invention;

Fig. 4 is an external perspective view of the inductance element including the high-frequency magnetic core shown in Fig. 3 and the coil surrounding the high-frequency magnetic core;

Fig. 5 is an external perspective view of the basic structure of an inductance element according to still another embodiment of the present invention.

Detailed ways

The present invention will be described in detail below.

As a result of intensive research, the inventors found that if the following alloy composition is selected as a soft magnetic metallic glass powder with excellent economic benefits, a powder with excellent magnetic properties and glass-forming properties can be obtained: (Fe _1-a Co _a ) _100-xyzqr (M _1-p M' _p ) _x T _y B _z C _q Al _r (0≤a≤0.50, 0≤p≤0.5, 2atom%≤x≤5atom%, 8atom%≤y≤ 12 atomic %, 12 atomic % ≤ z ≤ 17 atomic %, 0.1 atomic % ≤ q ≤ 1.0 atomic %, 0.2 atomic % ≤ r ≤ 2.0 atomic % and 25 ≤ (x+y+z+q+r) ≤ 30, M is at least one selected from Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W, and M' is selected from Zn, Sn and R (R is at least one selected from rare earth metals including Y. one), T is at least one selected from Si and P). In the present invention, "rare earth metal including Y" means that it consists of lanthanide elements such as La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu and another A group of elements Y. The inventors have also found that if a powder core is obtained by subjecting powder to oxidation or insulating coating, and then forming the powder into a molded body by a suitable molding method using a die or the like, the powder core is a material exhibiting excellent magnetic properties over a wide frequency band. Conductivity and high permeability powder cores with excellent performance that have never been obtained, so a high-frequency magnetic core composed of soft magnetic materials with high saturation magnetic flux density and high specific resistance can be prepared at low cost.

Furthermore, it was found that an inductive element obtained by providing a high-frequency magnetic core with at least one turn of the coil is cheap and has a high performance never before achieved.

The present inventors also found that by limiting the particle size of the soft magnetic metallic glass powder represented by the above general compositional formula, the powder core is excellent in core loss performance at high frequencies.

Furthermore, it was found that an inductive element obtained by providing a high-frequency magnetic core with at least one turn of the coil is cheap and has a high performance never before achieved. It was also found that an inductance element suitable for high-frequency high-current applications can be obtained by press-forming in a state in which a coil is embedded in a magnet to form an internal structure.

In order to increase the specific resistance of the molded body, the alloy powder before molding may be subjected to oxidation heat treatment in atmospheric air. In order to form a high-density molded body, molding may be continued at a temperature not lower than the softening point of the resin as a binder. In order to achieve a high density of the molded body, the molding can be performed in the subcooled liquid temperature range of the alloy powder.

Specifically, the soft magnetic metallic glass powder has an alloy composition represented by the following general formula: (Fe _1-a Co _a ) _100-xyzqr (M _1-p M' _p ) _x T _y B _z C _q Al _r (0≤ a ≤ 0.50, 0 ≤ p ≤ 0.5, 2 atomic % ≤ x ≤ 5 atomic %, 8 atomic % ≤ y ≤ 12 atomic %, 12 atomic % ≤ z ≤ 17 atomic %, 0.1 atomic % ≤ q ≤ 1.0 atomic %, 0.2 atomic %≤r≤2.0 atomic % and 25≤(x+y+z+q+r)≤30, M is at least one selected from Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W One, M' is at least one selected from Zn, Sn, R (R is at least one selected from rare earth metals including Y), and T is at least one selected from Si and P). The molded body is obtained by molding a mixture of soft magnetic metallic glass powder and a predetermined amount of a binder, the predetermined amount being a mass ratio relative to the soft magnetic metallic glass powder.

Here, the alloy composition of the soft magnetic metallic glass powder will be described. Fe as a main component is an element contributing to magnetism, and is an essential element for obtaining a high saturation magnetic flux density. Part of Fe can be replaced by Co in a ratio of 0-0.5. The substitution component has an effect of improving glass-forming properties, and is also expected to have an effect of improving saturation magnetic flux density. The total amount of Fe and substituting elements is in the range of not less than 70 atomic % and not more than 75 atomic % based on the entire alloy powder. This is because, if the content is not 70 atomic % or more, the saturation magnetic flux density is too low and practicality is lost, and if the content is more than 75 atomic %, the magnetic permeability of the core and core loss decrease due to crystallization .

Element M is a transition metal element required for improving glass-forming properties, which is at least one element selected from Zr, Nb, Ta, Hf, Mo, Ti, V, Cr, and W. The content of the element M is not less than 2 atomic % and not more than 5 atomic %.

This is because if the content is less than 2 atomic %, the glass formability decreases and the magnetic permeability and core loss remarkably deteriorate, and if the content exceeds 5 atomic %, the saturation magnetic flux density decreases and practicality is lost. By replacing the element M with a ratio of 0 to 0.5 by Zn, Sn, R (R is at least one element selected from rare earth metals including Y), the ratio of Fe and Co can be increased without deteriorating glass-forming properties, As a result, the saturation magnetic flux density can be improved.

Si and B are essential elements for the preparation of soft magnetic metallic glass powder. The Si content is in the range of not less than 8 atomic % and not more than 12 atomic %. The B content is in the range of not less than 12 atomic % and not more than 17 atomic %. This is because if the Si content is less than 8 atomic % or greater than 12 atomic % or if the B content is less than 12 atomic % or greater than 17 atomic %, the glass-forming performance decreases and stable soft magnetic glass powder cannot be produced. Here, Si may be replaced by P.

As long as Al and C are used with other component elements within the alloy composition range of the present invention, Al and C have the effect of forming the powder into a spherical shape when the powder is prepared by various atomization techniques. As for the amount added, if the Al content is less than 0.2 at%, the effect of forming spherical powder is small. If the Al content is greater than 2.0 atomic %, the amorphous-forming property deteriorates. Similarly, if the C content is less than 0.1 at%, the effect of forming spherical powder is small. If the C content is more than 1.0 at%, the amorphous-forming property deteriorates. Al and C can be used alone or in combination.

Soft magnetic metallic glass powders are prepared by water atomization or gas atomization. Preferably at least 50% of the particles have a particle size of not less than 10 μm. In particular, water atomization is considered to be a low-cost and high-volume method for producing alloy powders. The ability to prepare powders by this method has great advantages in industrial applications. However, if it is a conventional amorphous composition, alloy powders of 10 μm or larger will crystallize, so that the magnetic properties are significantly deteriorated. As a result, the yield is seriously lowered, thereby hindering industrial application. On the other hand, if the particle size is 150 μm or less, the soft magnetic metallic glass powder according to the present invention is easily vitrified (amorphized). Therefore, the yield is high. Therefore, considering the cost, the soft magnetic metallic glass powder of the present invention has great advantages. Furthermore, in the preparation of alloy powders by water atomization, suitable oxide coating films have been formed on the powder surfaces. Therefore, a core having a high specific resistance can be easily obtained by mixing a resin with an alloy powder and molding the mixture to form a molded body.

In any of the alloy powder prepared by water atomization and the alloy powder prepared by gas atomization, if the heat treatment is performed at a temperature not higher than the crystallization temperature of the alloy powder used and in atmospheric air, a more excellent oxide is formed Coating film. At this time, the specific resistance of the core can be increased to reduce the core loss of the core.

On the other hand, for inductive elements intended for high frequency applications, eddy current losses can be reduced by using metal powders with very small particle sizes. However, for alloy compositions well known in the art, if the average diameter is 30 μm or less, powder oxidation is significant during the preparation process. Therefore, it is difficult to obtain predetermined properties in powders prepared by conventional water atomization devices. However, the metallic glass powder has excellent alloy corrosion resistance, and thus the metallic glass powder is advantageous because a powder having a reduced oxygen content and excellent properties can be prepared relatively easily even if the powder is small.

Next, a method of molding a molded body is described. Basically, 10% by mass of a binder such as silicone resin is mixed with soft magnetic metallic glass powder. Molded bodies can be obtained using a die or by casting. This molded body is used as a high-frequency magnetic core, which has a powder filling ratio of 50% or more, has a magnetic flux density of 0.5 T or more on application of a magnetic field of 1.6×10 ⁴ A/m, and has a 1× Specific resistance of 10 ⁴ cm. Here, the content of the binder is 10% by mass or less. This is because, if the content exceeds 10%, the saturation magnetic flux density becomes equal to or less than that of ferrite, and the core loses practicality.

The molded body can be obtained by mixing soft magnetic metallic glass powder and a binder, and compression molding the mixture using a die, the amount of the binder being 5% or more in mass ratio to the soft magnetic metallic glass powder Small mass ratio. In this case, the molded body has a powder filling ratio of 70% or more, has a magnetic flux density of 0.75 T or more when a magnetic field of 1.6×10 ⁴ A/m is applied, and has a specific resistance of 1 Ωcm or more .When the magnetic flux density is 0.75T or more and the specific resistance is 1Ωm or more, the performance is superior and the practicality is further improved compared with the Sendust core.

In addition, the molded body can be obtained by mixing soft magnetic metallic glass powder and a binder, and compression-molding the mixture using a die at a temperature not higher than the softening point of the binder, so as to combine with the soft magnetic metallic glass powder In terms of mass ratio, the amount of binder is 3% or less by mass ratio. In this case, the molded body has a powder filling ratio of 80% or more, a magnetic flux density of 0.9 T or more when a magnetic field of 1.6×10 ⁴ A/m is applied, and a ratio of 0.1 Ωcm or more. resistance. When the magnetic flux density is 0.9T or more and the specific resistance is 0.1Ωm or more, its performance is more excellent and its practicality is further improved compared with any of the currently commercially available powder cores.

In addition, the molded body can be obtained by mixing soft magnetic metallic glass powder and a binder, and compression molding the mixture in the supercooled liquid temperature range of the soft magnetic metallic glass powder, at a mass ratio of the soft magnetic metallic glass powder In total, the amount of the binder is 1% by mass or less. In this case, the molded body has a powder filling ratio of 90% or more, a magnetic flux density of 1.0 T or more when a magnetic field of 1.6×10 ⁴ A/m is applied, and a ratio of 0.01 Ωcm or more. resistance. When the magnetic flux density is 1.0 T or more and the specific resistance is 0.01 Ωm or more, the magnetic flux density is substantially equal to that of a multilayer core including an amorphous metal and a high silicon steel plate in the application area. However, the molded body obtained here has small hysteresis loss and high specific resistance, so the core loss property is very excellent. Thus, the usability as a core is further improved.

In addition, after molding, the molded body as a high-frequency magnetic core may be heat-treated at a temperature not higher than the Curie point as strain-relieving heat treatment. In this case, core loss is further reduced, and usability as a core is further improved. Here, in order to maintain the insulation between the particles, it is necessary to contain SiO ₂ in at least part of the intermediate material between the alloy powder particles (alternatively, all the intermediate materials may be SiO ₂ ).

If it is necessary to form a gap on a part of the magnetic circuit, if the inductance element prepared by equipping the above-mentioned high-frequency magnetic core with at least one coil, a product that exhibits high magnetic permeability and excellent performance in a high magnetic field can be prepared.

Hereinafter, the present invention will be described in further detail with reference to the accompanying drawings.

Fig. 1 is an external perspective view showing the basic structure of a high frequency magnetic core 1 according to an embodiment of the present invention. FIG. 1 shows a state in which a high-frequency magnetic core 1 using the above-mentioned soft magnetic metallic glass powder is formed into an annular plate.

FIG. 2 is an external perspective view of the inductance element 101 obtained by equipping the high-frequency magnetic core 1 with a coil. FIG. 2 shows a state in which a coil 3 of a predetermined number of turns is wound around a high-frequency magnetic core 1 as an annular plate to prepare an inductance element 101 having lead wire pullout portions 3 a and 3 b.

FIG. 3 shows an external perspective view of the basic structure of a high-frequency magnetic core 1 according to another embodiment of the present invention. FIG. 3 shows a state in which a high-frequency magnetic core 1 using the above-mentioned soft magnetic metallic glass powder is formed into an annular plate and a gap 2 is formed on a part of the magnetic circuit.

FIG. 4 is an external perspective view of an inductance element 102 prepared by equipping a high-frequency magnetic core 1 with a coil 3 and having a gap 2 . 4 shows a state in which a predetermined number of turns of coil 3 is wound around high-frequency magnetic core 1 which is an annular plate having gap 2 to prepare inductance element 102 having lead wire pullout portions 3 a and 3 b.

If a powder core is formed by molding a mixture of soft magnetic metallic glass powder and a binder having the above metallic glass composition, the powder core exhibits very low loss properties at high frequencies, and has properties never obtained before The excellent performance of the soft magnetic metallic glass powder has a maximum particle size of 45 μm or less in particle size, and an average diameter of 30 μm or less, and in terms of the mass ratio of the soft magnetic metallic glass powder, the binder The content is 10% or less mass ratio. By equipping a powder core with a coil, an inductive element with excellent Q properties is obtained.

Furthermore, an inductance element suitable for large high-frequency currents can be obtained by press-forming a magnet with a coil embedded therein to form a complete structure.

Here, the reason for limiting the particle size of the powder will be described in detail. If the maximum grain size exceeds 45 μm in grain size, the Q property in the high-frequency region deteriorates. Furthermore, if the average diameter is not 30 µm or less, the Q property at 500 kHz or higher will not exceed 40. Furthermore, if the average diameter is not 20 µm or less, the Q value at 1 MHz or higher cannot be 50 or more. The advantage of metallic glass powder is that the Q property is high even at the same particle size because the specific resistance of the alloy itself is 2 to 10 times that of conventional materials. If the same Q properties are sufficient, the usable particle size range becomes wider, so that the powder production cost is reduced.

Fig. 5 is an external perspective view of the basic structure of a high frequency inductance element according to still another embodiment of the present invention. Referring to FIG. 5 , an inductance element 103 as a whole structure is obtained by press forming in a state in which a coil 7 obtained by winding a long plate-shaped material 5 formed of the above soft magnetic powder is embedded in a magnet 8 . The entire surface of the wound portion of the sheet material 5 is provided with an insulating coating 6 .

Now, the high-frequency magnetic core of the present invention and the inductance element using the high-frequency magnetic core will be described with reference to several examples including production processes and comparative examples.

(Examples 1 to 26, Comparative Examples 1 to 11)

First, as a powder preparation step, pure metal element materials including Fe, Si, B, Nb, Al, C and substitute elements or various master alloys if necessary are weighed so as to obtain a predetermined composition. By using these materials, various soft magnetic alloy powders are prepared by commonly used water atomization. Note here that mischmetal (misch) is a mixture of rare earth metals. Here, a mixture of 30% La, 50% Ce, 15% Nd and the balance of one or more other rare earth elements is used.

Next, as a molded body preparation step, various alloy powders were divided into alloy powders having a powder size of 45 μm or less. Subsequently, a silicone resin as a binder was mixed in at 4% by mass. Then, various molded bodies were formed by applying a pressure of 1.18 Gpa (about 12 t/cm ² ) at room temperature by using a die having grooves and having an outer diameter _φouter =27 mm and an inner diameter _φinner =14 mm, so that the mold The body height is equal to 5mm.

In addition, various molded bodies are subjected to resin curing. Subsequently, the weight and dimensions of each molded body were measured. Then, a coil with an appropriate number of turns is provided to prepare various inductive elements (having the shape shown in FIG. 2 ).

Next, for each different sample of the inductive element, the magnetic permeability was obtained from the inductance value at 100 kHz using an LCR meter. Furthermore, by using a DC magnetic property measuring device, the saturation magnetic flux density was measured when a magnetic field of 1.6×10 ⁴ A/m was applied. In addition, the upper and lower surfaces of each core were polished, and X-ray diffraction (XRD) measurement was performed to observe the phase state. The obtained results are shown in Table 1.

Table 1-1

Alloy Composition Magnetic flux density at 1.6×10⁴A/m Permeability at 100kHz XRD measurement results Comparative Example 1 Fe_72.5Si₉B_14.5Nb_2.5Al_1.0C_0.5 0.85/T twenty two crystalline phase

Alloy Composition Magnetic flux density at 1.6×10⁴A/m Permeability at 100kHz XRD measurement results Example 1 Fe₇₂Si₉B_14.5Nb₃Al_1.0C_0.5 0.82 31 vitreous phase Example 2 Fe₇₁Si₉B_14.5Nb₄Al_1.0C_0.5 0.77 33 vitreous phase Example 3 Fe₇₀Si₉B_14.5Nb₅Al_1.0C_0.5 0.72 35 vitreous phase Comparative Example 2 Fe₆₉Si₉B_14.5Nb₆Al_1.0C_0.5 0.67 37 vitreous phase Comparative Example 3 Fe_74.3Si_7.7B_13.5Nb₃Al_1.0C_0.5 0.92 19 Crystalline phase Example 4 Fe₇₄Si₈B_13.5Nb₃Al_1.0C_0.5 0.91 30 vitreous phase Example 5 Fe₇₂Si₁₀B_13.5Nb₃Al_1.0C_0.5 0.82 32 vitreous phase Example 6 Fe₇₀Si₁₂B_13.5Nb₃Al_1.0C_0.5 0.72 34 glass phase Comparative Example 4 Fe_69.5Si_12.5B_13.5Nb₃Al_1.0C_0.5 0.69 twenty one crystalline phase Comparative Example 5 Fe_75.5Si_8.5B_11.5Nb₃Al_1.0C_0.5 0.94 20 crystalline phase Example 7 Fe₇₅Si_8.5B₁₂Nb₃Al_1.0C_0.5 0.93 33 vitreous phase Example 8 Fe₇₂Si_8.5B₁₅Nb₃Al_1.0C_0.5 0.82 35 vitreous phase Example 9 Fe₇₀Si_8.5B₁₇Nb₃Al_1.0C_0.5 0.72 37 vitreous phase

Alloy Composition Magnetic flux density at 1.6×10⁴A/m Permeability at 100kHz XRD measurement results Comparative Example 6 Fe_69.5Si_8.5B_17.5Nb₃Al_1.0C_0.5 0.70 twenty three Crystalline phase Example 10 (Fe_0.9Co_0.1)₇₃Si₉B_14.5Nb₂Al_1.0C_0.5 0.87 31 vitreous phase Example 11 (Fe_0.7Co_0.3)₇₃Si₉B_14.5Nb₂Al_1.0C_0.5 0.89 33 vitreous phase Example 12 (Fe_0.5Co_0.5)₇₃Si₉B_14.5Nb₂Al_1.0C_0.5 0.87 35 vitreous phase Comparative Example 7 (Fe_0.4Co_0.6)₇₃Si₉B_14.5Nb₂Al_1.0C_0.5 0.85 37 vitreous phase Example 13 (Fe_0.7Co_0.3)₇₃Si₉B_14.5Ta₂A_l1.0C_0.5 0.88 34 vitreous phase Example 14 (Fe_0.7Co_0.3)₇₃Si₉B_14.5Mo₂Al_1.0C_0.5 0.87 35 vitreous phase Example 15 Fe₇₃Si₈B_14.5Nb_2.0Zn_1.0Al_1.0C_0.5 0.86 37 vitreous phase Example 16 Fe₇₃Si₈B_14.5Nb_1.5Zn_1.5Al_1.0C_0.5 0.86 35 vitreous phase

Table 1-2

Alloy composition Magnetic flux density at 1.6×10⁴A/m Permeance at 100kHz XRD measurement results Comparative Example 8 Fe₇₃Si₈B_14.5Nb_1.0Zn_2.0Al_1.0C_0.5 0.86 19 crystalline phase Example 17 Fe_73.5Si₈B_14.5Nb₂Zn_0.5Al_1.0C_0.5 0.89 33 vitreous phase Example 18 Fe₇₁Si₈B_14.5Nb_4.5Zn_0.5Al_1.0C_0.5 0.77 37 vitreous phase Comparative Example 9 Fe_70.5Si₈B_14.5Nb₅Zn_0.5Al_1.0C_0.5 0.74 35 crystalline phase Example 19 Fe₇₄Si₈B_14.5Nb_1.5Sn_0.5Al_1.0C_0.5 0.91 35 vitreous phase Example 20 Fe₇₄Si₈B_14.5Nb_1.5(rare earth metal mixture)_0.5Al _1.0C_0.5 0.90 35 vitreous phase Example 21 (Fe_0.7Co_0.3)₇₄Si₈B_14.5Nb_1.5Zn_0.5Al_1.0C_0.5 0.93 33 vitreous phase Example 22 (Fe_0.7Co_0.3)₇₄Si₈B_14.5Ta_1.5Zn_0.5Al_1.0C_0.5 0.92 32 vitreous phase Example 23 (Fe_0.7Co_0.3)₇₄Si₈B_14.5Mo_1.5Zn_0.5Al_1.0C_0.5 0.91 34 vitreous phase

Alloy composition Magnetic flux density at 1.6×10⁴A/m Permeance at 100kHz XRD measurement results Example 24 Fe_71.5Si₉B_14.5Nb₃Al_1.0C_1.0 0.79 33 vitreous phase Comparative Example 10 Fe_71.3Si₉B_14.5Nb₃Al_1.0C_1.2 0.77 16 crystalline phase Example 25 Fe_71.5Si₉B_14.5Nb₃Al_1.5C_0.5 0.79 33 vitreous phase Example 26 Fe₇₁Si₉B_14.5Nb₃Al_2.0C_0.5 0.79 33 vitreous phase Comparative Example 11 Fe_70.8Si₉B_14.5Nb₃Al_2.2C_0.5 0.76 15 crystalline phase

Table 1 shows the composition ratios of the samples. In addition, in the XRD pattern obtained by XRD measurement, if only a broad peak characteristic of a glass phase is found, it is judged to be a glass phase, and if a sharp peak attributable to crystallization is observed together with a broad peak, it is judged to be a (glass + crystal) phase, If a sharp peak is observed without a broad peak, it is judged to be a crystalline phase.

For those composition samples having a glassy phase, the glass transition temperature and crystallization temperature determined as DSC thermal analysis confirmed a subcooled liquid temperature range ΔTx of 30 K or higher for all samples. Here, ΔTx=Tx-Tg, where Tx denotes the crystallization temperature, and Tg denotes the glass transition temperature. The specific resistance of the molded body (core) was determined by two-terminal DC measurement. As a result, it was confirmed that all the samples exhibited an excellent specific resistance of not less than 1 Ωcm.

The temperature increase rate of DSC is 40K/min. From Examples 1 to 3 and Comparative Examples 1 and 2, it can be presumed that if the Nb content is 3 to 6%, a core having a glass phase can be obtained.

However, it was found that the magnetic flux density was as low as 0.70 T or less in Comparative Example 2 in which the Nb content was 6%.

From Examples 4-9 and Comparative Examples 3-6, it can be considered that if the Si content is 8-12, the B content is 12-17, and the Fe content is 70-75, a core having a glass phase can be obtained.

From Examples 10 to 14 and Comparative Example 7, it can be considered that by substituting Co for part of Fe, even if the Nb content is 2%, metallic glass powder can be obtained. However, it was found that if the substitution amount exceeds 0.5, the effect of improving the magnetic flux density cannot be obtained. It is also considered that a similar effect can be obtained by using Ta or Mo instead of Nb.

From Examples 15 and 16 and Comparative Example 8, it is considered that the saturation magnetic flux density can be improved by substituting Zn for Nb, but if the substitution ratio exceeds 0.5, the glass phase cannot be formed.

As for the total amount of Zn and Nb, it can be inferred from Examples 17 and 18 and Comparative Example 9 that 5% or less is suitable. It can be inferred from Examples 19 and 20 that if Sn or misch metal is added instead of Zn, a type effect is obtained.

It can be presumed from Examples 21 to 23 that similar effects can be obtained if part of Fe is replaced by Co, and type effects can be obtained if Ta or Mo is used instead of Nb. As shown in Examples 24 to 26 and Comparative Examples 11 and 12, Al may be added at a ratio of 2.0 or less, and C may be added at a ratio of 1.0 or less. However, if the added amount is larger, the ability to form an amorphous structure is remarkably poor.

(Example 27)

An alloy powder having a composition of (Fe _0.8 Co _0.2 ) ₇₃ Si ₉ B _14.5 Nb ₂ Al _1.0 C _0.5 was prepared by water atomization. The powder thus obtained was classified into a powder having a size of 75 μm or less. XRD measurement was carried out, and a broad peak characteristic of a glass phase was confirmed.

Next, DSC thermal analysis was performed to measure the glass transition temperature and the crystallization temperature, thereby confirming that ΔTx was 35K. Then, the powder was heat-treated in atmospheric air at 450°C below the glass transition temperature for 0.5 hours, thereby forming oxides on the powder surface. Next, the powder was mixed with 10%, 5%, 2.5%, 1% and 0.5% silicone. These powders were molded under three conditions of room temperature, 150°C above the softening temperature of the resin, and 550°C in the supercooled liquid temperature range of the metallic glass powder by using a φ27×φ14 die. Determination of powder filling ratio, magnetic flux density measured by DC magnetic properties, and DC specific resistance. The results obtained are shown in Table 2.

Table 2

sample number Resin content (%) Molding temperature Powder filling ratio (%) Magnetic flux density at 1.6×10⁴A/m Specific resistance Ωcm 1 0.5% room temperature 69.5 0.93 ＞100 2 1% room temperature 70.3 0.95 ＞100

sample number Resin content (%) Molding temperature Powder filling ratio (%) Magnetic flux density at 1.6×10⁴A/m Specific resistance Ωcm 3 2.5% room temperature 71.1 0.97 ＞100 4 5% room temperature 70.5 0.97 ＞100 5 10% room temperature 52.1 0.66 ＞10⁴ 6 0.5% 150℃ 81.3 1.12 5 7 1% 150℃ 81.9 1.14 10 8 2.5% 150℃ 82.5 1.16 15 9 5% 150℃ 71.0 0.95 >100 10 10% 150℃ 52.6 0.67 >10⁴ 11 0.5% 550°C 96.0 1.37 0.1 12 1% 550°C 92.8 1.31 0.5 13 2.5% 550°C 83.0 1.15 10 14 5% 550°C 71.4 0.97 >100 15 10% 550°C 52.3 0.67 >10⁴

It can be seen from Table 2 that when the content of the binder exceeds 5%, its specific resistance has a value as high as ≥ 10 ⁴ compared with that of the ferrite core. Because no special effect is obtained even if the molding temperature is increased , so molding at room temperature is sufficient. Second, when the amount of binder is equal to 5%, a specific resistance as high as 100Ωcm or higher is obtained, and molding at room temperature is sufficient. Secondly, it can be inferred that when the binder content When it is equal to 2.5%, if molding is performed at 150°C, the powder filling ratio is significantly improved, the magnetic flux density is high, and a specific resistance of 10Ωcm or higher is obtained. Secondly, it can be inferred that when the content of the binder is 1% and 0.5 %, if molding is performed at 550°C, the powder filling ratio is significantly improved, the saturation magnetic flux density is high, and a specific resistance of 0.1Ωcm or higher is obtained.

(Example 28)

In Example 28, an alloy powder having a composition of Fe ₇₂ Si ₉ B _14.5 Nb ₃ Al _1.0 C _0.5 was prepared by water atomization. Subsequently, the powder thus obtained was divided into powders having a particle size of 75 μm or less. Then, XRD measurements were performed to confirm the broad peaks characteristic of the glass phase.

In addition, DSC thermal analysis was performed to determine the glass transition temperature and crystallization temperature, thereby confirming that the glass transition onset temperature range or supercooled liquid temperature range ΔTx was 35K. Then, the powder was maintained and heat-treated for 0.5 hours in atmospheric air and at a temperature of 450° C. below the glass transition temperature to form oxides on the powder surface.

Next, the powder was mixed with 10%, 5%, 2.5%, 1% and 0.5% by mass of silicone resin as a binder. By using a grooved die with an outer diameter _φouter = 27mm x an inner diameter _φinner = 14mm, these powders were tested at three different temperature conditions, namely at room temperature, at 150°C above the softening temperature of the resin, and at the soft magnetic metal Under these three conditions of 550° C. in the supercooled liquid temperature range of the glass powder, molding was performed by using a pressure of 1.18 GPa (about 12 t/cm ² ) as the molding pressure so that the height was equal to 5 mm. In this way, various molded bodies were produced.

Next, the molded body thus obtained is subjected to resin curing. Subsequently, the weight and dimensions of each molded body were measured. Then, coils with an appropriate number of turns were wound to prepare various inductance elements (having the shapes shown in FIG. 2 ).

Then, for each different sample of the inductance element (No. 1 to 15), the powder filling ratio %, the magnetic flux density (at 1.6×10 ⁴ A/m) measured by DC magnetic properties, and the DC specific resistance Ωcm were determined. The results obtained are shown in Table 3.

table 3

sample number Resin content (%) Molding temperature Powder filling ratio (%) Magnetic flux density at 1.6×10⁴A/m Specific resistance Ωcm 1 0.5% room temperature 69.1 0.84 ＞100 2 1.0% room temperature 69.9 0.85 ＞100 3 2.5% room temperature 70.9 0.86 ＞100 4 5.0% room temperature 70.4 0.85 ＞100 5 10% room temperature 51.6 0.56 ＞10⁴ 6 0.5% 150℃ 80.9 1.04 5 7 1.0% 150℃ 81.6 1.06 10

sample number Resin content (%) Molding temperature Powder filling ratio (%) Magnetic flux density at 1.6×10⁴A/m Specific resistance Ωcm 8 2.5% 150℃ 82.3 1.08 15 9 5.0% 150℃ 70.7 0.86 ＞100 10 10% 150℃ 52.1 0.58 ＞10⁴ 11 0.5% 550°C 95.8 1.26 0.1 12 1.0% 550°C 92.5 1.21 0.5 13 2.5% 550°C 82.6 1.08 10 14 5.0% 550°C 71.1 0.87 ＞100 15 10% 550°C 51.8 0.58 ＞10⁴

As shown in Table 3, when the content of the binder (resin content) exceeds 5%, its specific resistance has a value as high as ≧10 ⁴ compared with that of the ferrite core. It is presumed that even if the molding temperature is raised, no special effect can be obtained, and molding conditions around room temperature are sufficient. In addition, it is presumed that when the resin content is equal to 5%, a specific resistance as high as 100 Ωcm or more is obtained, and molding at room temperature is sufficient.

In addition, it can be estimated that when the resin content is equal to 2.5%, if molding is performed at 150°C, the powder filling ratio is significantly improved, the magnetic flux density is high, and a specific resistance of 10 Ωcm or more is obtained. In addition, it is presumed that when the content of the binder is 1% and 0.5%, if the molding is performed at 550°C, the powder filling ratio is significantly improved, the saturation magnetic flux density is high, and a specific resistance of 0.1Ωcm or more is obtained.

(Example 29)

Using sample number 12 in Example 27, the inductance was measured in comparison with various core materials. In addition, a core prepared by using the same alloy powder and the same production process was heat-treated in a nitrogen atmosphere at 500°C for 0.5 hours to obtain another sample. The inductive properties of this sample are also shown. To normalize the inductance values, the obtained permeability was used for comparison. The core materials compared were Sendust, 6.5% silicon steel and iron-based amorphous metal.

Table 4

Sample name Magnetic flux density/T at 1.6×10⁴A/m Specific resistance Ωcm Permeability Core loss 20KHz 0.1T this invention 1.31 0.5 150 50/mW/cc

Sample name Magnetic flux density/T at 1.6×10⁴A/m Specific resistance Ωcm Permeability Core loss 20KHz 0.1T The present invention (heat treatment) 1.33 0.4 200 30 MnZn ferrite 0.55 ＞10⁴ 100^* 10 Sendust 0.65 100 80 100 6.5% silicon steel 1.0 100μ 100^* 250 Iron-based amorphous metal 1.3 150μ 100^* 400

Note) ^* For the gap embedded in part of the magnetic circuit energy specification (power specification)

As can be seen from Table 4 above, the inductance element of the present invention has a magnetic flux density equal to that of an inductance element using an amorphous metal, and exhibits lower core loss properties than that of an inductance element using Sendust. Therefore, the inductance element of the present invention can be used as a very excellent inductance element. It has been confirmed that in the inductance element using the heat-treated core, the magnetic permeability and core loss are further improved.

(Example 30)

In Example 30, an inductance element was prepared by using the material corresponding to sample No. 12 in Example 28. In addition, another inductance element was prepared by using the same alloy powder and the same production process, and heat-treating at 500°C for 0.5 hour in a nitrogen atmosphere. In addition, for comparison, an inductance element (including a structure with a gap on a part of the magnetic circuit as shown in FIG. 4 ) was prepared by using Sendust, 6.5% silicon steel, and iron-based amorphous metal as core materials, respectively. For those inductance elements, the magnetic flux density (1.6×10 ⁴ A/m) measured by DC magnetic properties, DC specific resistance Ωcm, magnetic permeability for inductance value normalization, and core loss (20 kHz 0.1T) were measured. The results shown in Table 5 were obtained.

table 5

Sample name Magnetic flux density/T at 1.6×10⁴A/m Specific resistance Ωcm Permeability Core loss 20KHz 0.1T this invention 1.21 0.5 160 50/mW/cc The present invention (heat treated) 1.23 0.4 220 25 MnZn ferrite 0.55 ＞10⁴ 100^* 9 Sendust 0.65 100 80 100 6.5% silicon steel 1.0 100μ 100^* 250 Iron-based amorphous metal 1.3 150μ 100^* 400

It can be seen from Table 5 that the inductance element of the present invention has a magnetic flux density equal to that of the inductance element using Fe-based amorphous metal as the core, and exhibits lower core loss than that of the inductance element using Sendust as the core Magnetic core loss. Therefore, the inductance element of the present invention has very excellent properties. It has been confirmed that in the inductance element using the heat-treated core, the magnetic permeability and core loss are further improved, and more excellent performance is obtained.

(Example 31)

In Example 31, an alloy powder having a composition of Fe ₇₂ Si ₉ B _14.5 Nb ₃ Al _1.0 C _0.5 was prepared by water atomization. The obtained powder is subsequently divided into powders having a particle size of 45 μm or less. Then, XRD tests were performed to confirm the broad peaks characteristic of the glassy phase.

In addition, DSC thermal analysis was performed to determine the glass transition temperature and crystallization temperature, thereby confirming that the supercooled liquid temperature range ΔTx was 35K. Then, the powder obtained by water atomization and having the alloy composition shown in Table 6 below was filtered through a standard sieve into a powder of 20 μm or smaller. These powders were mixed in the proportions shown in Table 6.

Furthermore, using the powder thus obtained, it was mixed with a silicone resin as a binder in a content of 1.5% by mass. These powders were molded at room temperature using a pressure of 12 t/cm ² to make a height equal to 5 mm by using a grooved die with an outer diameter _φout = 27 mm x an inner diameter _φin = 14 mm. In this way, various kinds of molded bodies are produced. After molding, heat treatment was performed in an Ar atmosphere at 500°C.

Next, the various molded bodies thus obtained were subjected to resin curing. Subsequently, the weight and dimensions of each molded body were measured. Then, coils with an appropriate number of turns were wound to prepare various inductance elements (having the shapes shown in FIG. 2 ).

Then, for each different sample of the inductance element, powder filling ratio %, magnetic permeability and core loss (20 kHz 0.1 T) were determined. The results shown in Table 6 were obtained.

Table 6

It can be seen from Table 6 that the inductance element of the present invention improves the filling ratio of the powder by adding soft magnetic powder with smaller particle size to the metallic glass powder, thereby improving the magnetic permeability. On the other hand, if the added amount exceeds 50%, the improvement effect becomes poor, and the core loss property is remarkably deteriorated. Therefore, it can be presumed that the added amount is preferably 50% or less.

(Example 32)

In Example 32, an alloy powder having a composition of Fe _73.5-qr Si ₉ B _14.5 Nb ₃ C _q Al _r in which q and r were varied differently was prepared by water atomization. Thus, powders having aspect ratios shown in Table 7 were prepared. The obtained powder is subsequently divided into powders having a particle size of 45 μm or less. Then, XRD tests were performed to confirm the broad peaks characteristic of the glassy phase. In addition, DSC thermal analysis was performed to determine the glass transition temperature and crystallization temperature, thereby confirming that the supercooled liquid temperature range ΔTx was 35K.

Furthermore, using the powder thus obtained, it was mixed with a silicone resin as a binder in a content of 3.0% by mass. These powders were molded at room temperature using a pressure of 1.47 GPa (15 t/cm ² ) to a height equal to 5 mm by using a grooved die with an outer diameter _φout = 27 mm x an inner diameter _φin = 14 mm. In this way, various kinds of molded bodies are prepared. After molding, heat treatment was performed in an Ar atmosphere at 500°C.

Next, the various molded bodies thus obtained were subjected to resin curing. Subsequently, the weight and dimensions of each molded body were measured. Then, coils with an appropriate number of turns were wound to prepare various inductance elements (having the shapes shown in FIG. 2 ).

Then, for each different sample of the inductance element, the powder filling ratio % and the magnetic permeability were determined. The results shown in Table 7 were obtained.

Table 7

As shown in Table 7, the inductance element of the present invention improves the magnetic permeability by increasing the aspect ratio of the metallic glass powder. On the other hand, if the aspect ratio exceeds 2, the initial magnetic permeability is high, but the magnetic permeability becomes poor under DC superposition. Therefore, it can be inferred that the aspect ratio of the powder is preferably 2 or less.

(Example 33)

First, as a powder preparation step, the material was weighed to obtain a composition of Fe _72.0 Si ₉ B _14.5 Nb ₃ C _0.5 Al _1.0 . Using the material, micro powders of soft magnetic alloys with different median particle sizes are prepared by high-pressure water atomization.

Next, as a molded body preparation step, the alloy powders thus obtained were filtered through various kinds of standard sieves to obtain powders shown in Table 8. Subsequently, a silicone resin as a binder was mixed in an amount of 3% by mass. Then, using a die head of 10mm×10mm, each powder was molded and arranged with a coil having an outer diameter _φout = 8, an _inner diameter φin = 4mm, and a height of 2mm so that the molded coil was located at the molded The exact center of the body, by applying a pressure of 490MPa at room temperature, so that the height is 4mm. Thus, a molded body is formed.

Next, resin curing was performed at 150°C. As for Sample No. 5, another sample was also prepared by heat-treating the inductor element at 500°C in a nitrogen atmosphere for 0.5 hours.

Next, for each different sample of the inductive element, the inductance and resistance were measured at different frequencies using an LCR meter. From the measurement, when the inductance value is 1MHz, the peak frequency Q and the peak value Q can be obtained. The results obtained are shown in Table 8.

Next, for the same sample of the inductive element, the energy conversion efficiency was determined using an evaluation kit for a typical DC/DC converter. The results obtained are as follows. The measurement conditions were 12V input, 5V output, 300kHz drive frequency, and 1A output current.

Table 8

sample number Mesh size μm The average diameter L(μH) at 1MHZ Q peak frequency Q peak Energy conversion efficiency Comparative Example 1 45 33 0.58 300kHz 32 79.6% 1 45 28 0.61 600kHz 44 83.1

sample number Mesh size μm The average diameter L(μH) at 1MHZ Q peak frequency Q peak Energy conversion efficiency 2 45 twenty three 0.64 800kHz 47 83.7 3 45 18 0.67 1.5MHz 62 85.2 4 45 15 0.65 2.5MHz 67 85.4 5 45 10 0.63 3.5MHz 77 85.7 5 (heat treated) 45 10 0.70 3.0MHz 82 87.3 Comparative Example 2 63 28 0.67 400kHz 35 79.8

From Table 8, in the inductance element of the present invention, when the mesh particle size is 45 µm or less and the average diameter is 30 µm or less, the Q peak frequency is 500 kHz or more, and the Q peak value is 40 or more. Meanwhile, the energy conversion efficiency is very excellent at 80% or more. When the mesh particle size is 45 m or less and the average diameter is 20 μm or less, the Q peak frequency is 1 MHz or more, and the Q peak value is 50 or more. Meanwhile, the energy conversion efficiency is very excellent at 85% or more. In addition, it can be inferred that the conversion efficiency can be further improved by heat-treating the inductance element.

As mentioned above, in the high-frequency magnetic core according to the present invention, the alloy composition of the following general formula is selected as the soft magnetic metallic glass powder with excellent economic benefits: (Fe _1-a Co _a ) _100-xyzqr (M _1-p M' _p ) _x T _y B _z C _q Al _r (0 ≤ a ≤ 0.50, 0 ≤ p ≤ 0.5, 2 atomic % ≤ x ≤ 5 atomic %, 8 atomic % ≤ y ≤ 12 atomic %, 12 atomic % ≤ z≤17 atomic %, 0.1 atomic %≤q≤1.0 atomic %, 0.2 atomic %≤r≤2.0 atomic % and 25≤(x+y+z+q+r)≤30, M is selected from Zr, Nb, At least one of Ta, Hf, Mo, Ti, V, Cr and W, M' is at least one selected from Zn, Sn, and R (R is at least one element selected from rare earth metals including Y) One, T is at least one selected from Si and P). This makes it possible to obtain excellent magnetic properties, glass-forming properties, and powder filling capabilities. In addition, the powder is subjected to oxidation or insulating coating, and molded by using a die or the like and using an appropriate molding method to obtain a molded body. In this way, powder cores are prepared. Thus, a never-before-known high-permeability powder core exhibiting excellent permeability properties over a wide frequency range is obtained. Therefore, a soft magnetic material high frequency core with high saturation magnetic flux density and high specific resistance can be produced economically. Furthermore, an inductive element comprising a high-frequency magnetic core and at least one coil wound around the high-frequency magnetic core is obtained, which is an economical and high-performance product that has never been obtained. Therefore, the present invention is very useful in industrial applications.

In the present invention, if a metallic glass powder having a maximum particle size of 45 μm or less in particle size and an average diameter of 30 μm or less, more desirably 20 μm or less is used, a material having very low loss properties at high frequencies is obtained. powder core. An inductance element including a high-frequency magnetic core and at least one coil wound around the high-frequency magnetic core has excellent Q performance so that energy supply efficiency can be improved. Therefore, the present invention is very useful in industrial applications.

Furthermore, in the present invention, metallic glass powder having a maximum particle size of 45 μm or less in particle size and an average diameter of 30 μm or less, more desirably 20 μm or less, is pressure-molded with a coil embedded in a magnet to form a complete structure. In this case, in addition to the excellent core properties characteristic of the metallic glass phase, heat generated from the current flowing through the coil is radiated through the metallic magnet. Through the synergistic effect of heat radiation, an inductance element with an increased rated current can be obtained for the same shape. Here, the strain relief heat treatment temperature of the metallic glass powder is lower than the temperature above 600° C., which is considered to be the upper limit of the allowable temperature of the copper wire and the coating material used in the coil. Therefore, by heat treatment at a temperature not higher than 600°C, a coil with significantly reduced loss can be obtained. Therefore, the alloy composition of the present invention is very suitable as a powder forming a core having a coil and powder integral structure.

As described above, the high-frequency magnetic core of the present invention is economically obtained by using a soft magnetic metallic glass material having a high saturation magnetic flux density and a high specific resistance. In addition, an inductance element obtained by equipping a core with a coil has excellent magnetic properties in a high frequency band that have never been seen before. Therefore, it is possible to prepare a high-permeability powder core of low cost and excellent performance which has never been done before, which is suitable for energy supply elements of various electronic devices such as choke coils and transformers.

Using the high-frequency magnetic core obtained by molding powder with a fine particle size in the present invention, a high-performance inductance element at high frequency can be produced. Also, in the high-frequency magnetic core obtained by molding fine-grained powder, the coil embedded in the magnet is compression-molded to form a monolithic structure. Therefore, it is possible to obtain an inductance element that is small in size and suitable for a large current, which is suitable as an inductance element such as a choke coil and a transformer.

Claims (20)

1. A high-frequency magnetic core comprising a molded body obtained by molding a mixture of soft magnetic metallic glass powder and a binder, the binder being in mass ratio relative to the soft magnetic metallic glass powder content of 10% or less, the soft magnetic metallic glass powder has an alloy composition represented by the general formula: (Fe _1-a Co _a ) _100-xyzqr (M _1-p M' _p ) _x T _y B _z C _q Al _r , where 0 ≤ a ≤ 0.50, 0 ≤ p ≤ 0.5, 2 atomic % ≤ x ≤ 5 atomic %, 8 atomic % ≤ y ≤ 12 atomic %, 12 atomic % ≤ z ≤ 17 atomic %, 0.1 atomic % %≤q≤1.0 atomic %, 0.2 atomic %≤r≤2.0 atomic % and 25≤(x+y+z+q+r)≤30, M is selected from Zr, Nb, Ta, Hf, Mo, Ti, At least one of V, Cr and W, M' is at least one selected from Zn, Sn and R, R is at least one element selected from rare earth metals including Y, and T is selected from Si and P at least one of the 2. The high-frequency magnetic core according to claim 1, wherein the molded body has a powder filling ratio of 50% or more, and has a power of 0.5 T or more when a magnetic field of 1.6×10 ⁴ A/m is applied. magnetic flux density, and have a specific resistance of 1×10 ⁴ Ωcm or more. 3. The high-frequency magnetic core as claimed in claim 1, wherein the molded body is obtained by preparing a mixture of soft magnetic metallic glass powder and a binder and compression molding the mixture using a die, so as to be relatively soft magnetic The amount of the binder is 5% or less in terms of mass ratio of metallic glass powder, the molded body has a powder filling ratio of 70% or more, when a magnetic field of 1.6×10 ⁴ A/m is applied It has a magnetic flux density of 0.70T or more, and has a specific resistance of 1Ωcm or more. 4. The high-frequency magnetic core as claimed in claim 1, wherein said molded body is obtained by preparing a mixture of soft magnetic metallic glass powder and a binder and using a die head at a temperature not lower than the softening point of the binder Obtained by compression molding the mixture, the amount of the binder is 3% or less in terms of mass ratio relative to the soft magnetic metallic glass powder, and the molded body has a powder filling ratio of 80% or more , has a magnetic flux density of 0.9 T or more when a magnetic field of 1.6×10 ⁴ A/m is applied, and has a specific resistance of 0.1 Ωcm or more. 5. The high-frequency magnetic core as claimed in claim 1, wherein said molded body is compression molded by preparing a mixture of soft magnetic metallic glass powder and binder and in the supercooled liquid temperature range of soft magnetic metallic glass powder The mixture is obtained, the amount of the binder is 1% or less in terms of mass ratio relative to the soft magnetic metallic glass powder, the molded body has a powder filling ratio of 90% or more, and when applied It has a magnetic flux density of 1.0 T or more at a magnetic field of 1.6×10 ⁴ A/m, and has a specific resistance of 0.01 Ωcm or more. 6. The high frequency magnetic core according to claim 1, wherein the soft magnetic metallic glass powder is produced by water atomization or gas atomization, and at least 50% of the powder particles have a size of not less than 10 [mu]m. 7. The high frequency magnetic core as claimed in claim 1, wherein the soft magnetic metal alloy powder having an average diameter smaller than that of the soft magnetic metallic glass powder and low hardness is added in an amount of 5-50% by volume. 8. The high frequency magnetic core according to claim 1, wherein the soft magnetic metallic glass powder has an aspect ratio in the range of 1-2, ie major axis/minor axis. 9. The high-frequency magnetic core as claimed in claim 1, wherein after molding, the molded body is heat-treated at a temperature not lower than the Curie point of the alloy powder, and _{SiO is} at least contained between the powder particles of the alloy powder part of the intermediate material. 10. The high-frequency magnetic core according to claim 1, wherein the soft magnetic metallic glass powder has a maximum particle size of 45 [mu]m or less in mesh size and an average diameter of 30 [mu]m or less. 11. The high frequency magnetic core as claimed in claim 10, wherein the soft magnetic metal alloy powder having an average diameter smaller than that of the soft magnetic metallic glass powder and low hardness is added in an amount of 5-50% by volume. 12. The high-frequency magnetic core according to claim 10, wherein the soft magnetic metallic glass powder has an aspect ratio in the range of 1-2, ie major axis/minor axis. 13. The high frequency magnetic core according to claim 10, wherein the powder filling ratio is 50% or more, and the Q peak at 500 kHz or more is 40 or more. 14. The high-frequency magnetic core as claimed in claim 10, wherein said soft magnetic metallic glass powder has a maximum powder particle size of 45 μm or less and an average diameter of 20 μm or less on the grid size, and at 1 MHz or When larger, the peak Q of the high-frequency core is 50 or greater. 15. An inductance element comprising the high-frequency magnetic core as claimed in claim 1 and at least one coil wound around the high-frequency magnetic core. 16. The inductance element according to claim 15, wherein a gap is formed on a part of the magnetic circuit of the high frequency magnetic core. 17. An inductance element, comprising the high-frequency magnetic core according to claim 10 and at least one coil wound around the high-frequency magnetic core. 18. The inductive element of claim 17, wherein the coil is embedded in a magnet and formed by compression molding into a unitary structure. 19. The inductance element according to claim 17, wherein the molded body forms at least one turn of a coil embedded in a magnet and formed into an integral structure by compression molding. 20. The inductor element according to claim 17, wherein the heat treatment is performed at a temperature not higher than 600°C.

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