JP7100833B2 - Magnetic core core and its manufacturing method, and coil parts - Google Patents

Description

The present invention relates to a magnetic core core and a method for manufacturing the same, and more specifically, a magnetic core core using an alloy-based magnetic material powder and a method for manufacturing the magnetic core core, and a reactor and an inductor using the magnetic core core. Regarding coil parts.

Magnetic material powders, especially amorphous alloy magnetic material powders with excellent soft magnetic properties, have good magnetic properties such as relative permeability and saturation magnetic flux density and are suitable for use in the high frequency range. It is actively researched and developed.

For example, Patent Document 1 describes a step of preheating an Fe-based amorphous metal strip (metal ribbon) produced by a rapid coagulation method (RSP); the amorphous metal strip is crushed and amorphous. Step to obtain metal powder; After classifying the amorphous metal powder, a powder having a particle size distribution consisting of -100 to +140 mesh passage: 35 to 45% and -140 to +200 mesh passage: 55 to 65% is mixed. Steps; Amorphous including a step of mixing a binder with the mixed amorphous metal powder and then molding a core; and a step of annealing the molded core and then coating the core with an insulating resin. A method for manufacturing a soft magnetic core has been proposed.

In Patent Document 1, an amorphous metal powder having high composition uniformity and a low degree of oxidation is obtained by crushing a metal strip produced by a rapid coagulation method, and the amorphous metal powder is pressurized. We are trying to obtain a magnetic core core that has good DC superimposition characteristics even under high current energization by molding.

Japanese Patent No. 4274897 (Claim 1, paragraphs [0017], [0018], etc.)

However, in Patent Document 1, although the metal strip is pulverized to obtain an amorphous magnetic material powder, the pulverized magnetic material powder has a distorted shape and has a sharp edge portion. Therefore, if pressure molding is performed in a state where the edge portions are in contact with each other, the magnetic flux is concentrated on the edge portions, which may lead to deterioration of the DC superimposition characteristic.

In addition, since the magnetic material powder is easily distorted because it is machined by applying an external force to the metal strip for a long time, the coercive force Hc of the magnetic material powder increases and hysteresis loss occurs. It may become large and cause an increase in magnetic loss.

Further, in a magnetic core core using this kind of magnetic material powder, the insulating property is usually secured by coating the magnetic material powder with an insulating material, but the magnetic material powder has a sharp edge portion. Therefore, it is difficult to uniformly coat the magnetic powder with the insulating material. For this reason, the insulating property between the magnetic powders is insufficient and the current easily leaks, which causes an increase in the eddy current loss, which may increase the magnetic loss.

The present invention has been made in view of such circumstances, and is a magnetic core core using a magnetic material powder capable of reducing magnetic loss and having good DC superimposition characteristics, a method for manufacturing the same, and the magnetic core. It is an object of the present invention to provide coil parts such as reactors using a core.

The magnetic material powder obtained by crushing the metal strip has a distorted and sharp edge portion, but when the magnetic material powder becomes close to a spherical surface, the formation of the above-mentioned distorted and sharp edge portion is suppressed. It is considered that the magnetic flux diffuses and flows on the spherical surface substantially uniformly without being concentrated on a specific part, which makes it possible to improve the DC superimposition characteristic.

On the other hand, when an external force is applied to the metal strip for a long time to make the magnetic powder excessively spheroidized, the magnetic powder is greatly distorted, so that the coercive force Hc of the magnetic powder increases and hysteresis loss occurs. It may increase and lead to an increase in magnetic loss.

Therefore, the present inventors made a flat spherical powder so that the magnetic flux diffused and flowed substantially uniformly while suppressing the strain formation of the magnetic powder, and conducted diligent research. As a result, the average length in the radial direction was obtained. The aspect ratio a / b, which indicates the ratio of a to the average thickness b in the thickness direction, is set to 1.8 to 6.8, and the corners are formed to have a curved shape with a radius of 0.8 μm to 25 μm. It was found that a magnetic powder suitable for a magnetic core core with low magnetic loss and good DC superimposition characteristics can be obtained. By forming cracks in 50% or more of the magnetic powder on a quantity basis, even if the magnetic powder is distorted when the metal strip is crushed, the strain is released during pressure molding. It was also found that the presence of cracks allows the magnetic powder to be filled at a high density, which makes it possible to further improve the DC superimposition characteristics and reduce the magnetic loss.

The present invention has been made based on such findings, and the magnetic core core according to the present invention is a composite material containing a magnetic powder made of a pulverized metal strip containing at least an Fe component and a binder. The magnetic core is formed in a flat spherical shape, and has an aspect ratio a / b indicating the ratio of the average length a in the radial direction and the average thickness b in the thickness direction. It is 1.8 to 6.8, has a curved corner with a radius of 0.8 μm to 25 μm , and the magnetic powder is characterized in that cracks are formed in 50% or more on a quantity basis. There is.

By defining the aspect ratio a / b and the shape of the corners of the magnetic powder in this way, it is possible to suppress the occurrence of distortion, and the magnetic flux diffuses substantially uniformly on the spherical surface without concentrating on a specific part. Therefore, it is possible to achieve both low magnetic loss and improvement of DC superimposition characteristics.

Further, it is preferable that the magnetic powder of the present invention contains Fe as a main component and a mixture of an amorphous phase and a nanocrystal phase.

As a result, it is possible to obtain a magnetic core core having good soft magnetic characteristics, low magnetic loss, good mechanical strength, and good magnetic characteristics such as relative permeability and magnetic flux saturation density and DC superimposition characteristics.

Further, the magnetic powder of the present invention preferably has an average particle size of 30 to 80 μm in terms of a diameter equivalent to a circle.

Here, the above-mentioned average particle diameter means a cumulative 50% particle diameter D ₅₀ (median diameter).

Further, the method for manufacturing a magnetic core core according to the present invention is a method for manufacturing a magnetic core core formed of a composite material containing a magnetic powder and a binder, and comprises a magnetic powder powder manufacturing step and a composite material manufacturing step. The magnetic powder manufacturing step includes a step of manufacturing a metal strip containing at least an Fe component, a step of crushing the metal strip to prepare a crushed product, and a spheroidizing treatment of the crushed product. , The aspect ratio a / b indicating the ratio between the average length a in the radial direction and the average thickness b in the thickness direction is 1.8 to 6.8, and the corners are curved with a radius of 0.8 μm to 25 μm. The composite material manufacturing step includes a step of producing a flat spherical magnetic material powder so as to be formed so as to be formed, and the composite material manufacturing step is a mixture of a first binder containing a silicone resin as a main component and the magnetic material powder. From the step of coating the magnetic powder with the first binder, the magnetic powder coated with the first binder, and at least one resin having a hardness higher than that of the first binder. The first binder is mixed with the second binder, and the first binder is bonded to each other via the second binder, and the composite containing the magnetic powder and the first and second binders. It is characterized by including a step of producing a material and a step of forming a magnetic core core by pressure molding the composite material so that cracks are formed in 50% or more of the magnetic powder on a quantity basis .

As a result, the metal strip is crushed until it becomes approximately a predetermined size, and a magnetic powder having the above aspect ratio a / b and a predetermined curved surface shape at the corners can be produced by the subsequent spheroidizing treatment, resulting in low magnetic loss. Therefore, it is possible to efficiently obtain a magnetic powder having good DC superimposition characteristics at low cost.

Further, the method for producing a magnetic powder of the present invention preferably includes a step of heat-treating the metal strip to precipitate nanocrystals in an amorphous phase.

Since the metal strip is heat-treated to precipitate nanocrystals in the amorphous phase in this way, the temperature is complicated unlike the case where the atomized powder produced by the atomizing method is heat-treated to precipitate nanocrystals. High-quality magnetic powder that does not require control, has good DC superimposition characteristics, and has low magnetic loss can be obtained with high efficiency.

Further, in the method for producing a magnetic powder of the present invention, it is preferable to heat-treat the spheroidized magnetic powder.

As a result, the strain generated during the pulverization treatment of the metal strip including the spheroidizing treatment can be effectively removed, and a magnetic material powder having an even lower magnetic loss can be obtained.

Further, in the method for producing a magnetic powder of the present invention, the step of producing the metal strip is the step of weighing and blending a predetermined raw material containing at least an Fe component, and the step of heating the blended preparation. It is preferable to include a step of producing a melt and a step of ejecting the melt onto a rotating body to quench and solidify it to form a metal strip.

By producing the metal strip by the single roll quenching method and pulverizing the metal strip in this way, it is possible to obtain a desired magnetic material powder with high efficiency.

Further, the magnetic core core according to the present invention is characterized in that it is formed of a composite material containing the magnetic powder described in any of the above and a binder.

As a result, it is possible to obtain a magnetic core core having good DC superimposition characteristics, low magnetic loss, and good mechanical strength.

Specifically, the binder contains a first binder containing a silicone resin as a main component and a second binder composed of at least one resin having a higher hardness than the first binder. It is preferable that the magnetic powder is coated with the first binder and the first binders are bonded to each other via the second binder.

As a result, the magnetic powder is coated with the first binder containing silicone as a main component, which has good insulating properties, so that electricity leakage from the magnetic powder can be suppressed, eddy current loss can be reduced, and low magnetism can be achieved. Loss is possible. Further, since the magnetic powders coated with the first binder are bonded to each other via a second binder having a higher hardness than the first binder, the second binder having a higher hardness is used. The mechanical strength is improved, and it is possible to prevent damage even when a large external force is applied.

Further, in the magnetic core core of the present invention, it is preferable that the second binder contains at least one of a phenol resin and a polyimide resin.

Further, in the magnetic core core of the present invention, it is preferable that the silicone resin is a methylphenyl type.

That is, since the methylphenyl-based silicone resin has a small shrinkage rate during molding, it is possible to suppress distortion of the magnetic powder during molding, and it is possible to suppress an increase in hysteresis loss without requiring heat treatment at a high temperature. Therefore, it is possible to contribute to the reduction of the magnetic loss of the magnetic core core.

Further, in the magnetic core core of the present invention, it is preferable that the magnetic powder has cracks of 50% or more on a quantity basis.

By forming cracks in the magnetic powder having a quantity of 50% or more in this way, even if the magnetic powder is distorted when the metal strip is crushed, the strain is released during pressure molding. In addition, the presence of cracks allows the magnetic powder to be filled at a high density, which makes it possible to further improve the DC superimposition characteristics and reduce the magnetic loss.

Further, in the magnetic core core of the present invention, it is preferable that the composite material contains fine particles made of a magnetic metal material containing Fe as a main component having an average particle size of 1 to 50 μm in terms of a circle equivalent diameter. The fine particles are preferably atomized powder.

Here, the average particle size means a cumulative 50% particle size D ₅₀ (median diameter).

As a result, fine particles made of a magnetic metal material are filled in the gaps between the magnetic powders, so that the magnetic permeability and the DC superimposition characteristics can be further improved.

Further, the method for producing a magnetic core core of the present invention preferably includes a step of mixing the magnetic powder and fine particles made of a magnetic metal material.

As a result, the fine particles are easily filled in the gaps between the magnetic powders, so that a magnetic core core having further improved various magnetic properties can be obtained.

Further, the coil component according to the present invention is characterized by including the magnetic core core and the coil conductor according to any one of the above.

Further, the coil component of the present invention is characterized in that the coil conductor is wound around the magnetic core core.

According to the magnetic core core of the present invention, the magnetic core is a magnetic core formed of a composite material containing a magnetic material powder made of a pulverized metal strip containing at least an Fe component and a binder, and the magnetic material powder is the magnetic core powder. The aspect ratio a / b, which is formed into a flat spherical surface and indicates the ratio between the average length a in the radial direction and the average thickness b in the thickness direction, is 1.8 to 6.8, and the corner portion has a radius of 0. Since the magnetic material powder has a curved surface shape of 8.8 μm to 25 μm and cracks are formed in 50% or more on a quantity basis, the magnetic material powder defines the aspect ratio a / b and the shape of the corners. As a result, it is possible to suppress the occurrence of distortion, and the magnetic flux diffuses and flows on the spherical surface substantially uniformly without concentrating on a specific part, so that both low magnetic loss and improvement of DC superimposition characteristics can be achieved at the same time. Is possible. Moreover, since cracks are formed in 50% or more of the magnetic powder on a quantity basis, even if the magnetic powder is distorted when the metal strip is crushed, the strain is released during pressure molding. Further, since the magnetic powder is filled with a high density due to the presence of cracks, the mechanical strength is good, and further improvement of DC superimposition characteristics and low magnetic loss are possible.

According to the method for producing a magnetic core core of the present invention, it is a method for producing a magnetic core core formed of a composite material containing a magnetic material powder and a binder, and has a magnetic material powder production step and a composite material production step. The magnetic powder manufacturing step is a step of producing a metal strip containing at least an Fe component, a step of crushing the metal strip to prepare a crushed product, and a spheroidizing treatment of the crushed product. The aspect ratio a / b, which indicates the ratio between the average length a in the radial direction and the average thickness b in the thickness direction, is 1.8 to 6.8, and the corners are curved with a radius of 0.8 μm to 25 μm. The composite material manufacturing step includes a step of preparing a flat spherical magnetic material powder so as to be formed as described above, and the composite material manufacturing step is a mixture of a first binder containing a silicone resin as a main component and the magnetic material powder. From the step of coating the magnetic powder with the first binder, the magnetic powder coated with the first binder and at least one resin having a hardness higher than that of the first binder. The first binder is mixed with the second binder, the first binder is bonded to each other via the second binder, and the magnetic powder and the first and second binder are contained in the composite. Since it includes a step of producing a material and a step of forming a magnetic core core so that the magnetic powder is cracked to 50% or more on a quantity basis by pressure molding the composite material, the magnetic loss is low. A magnetic core core with good DC superimposition can be efficiently manufactured.

According to the coil component of the present invention, since the magnetic core core and the coil conductor described in any of the above are provided, a reactor or the like having good DC superimposition characteristics and low magnetic loss and suitable for use in a high frequency region can be used. Coil parts can be obtained.

It is a figure which shows one Embodiment of the particle shape of the magnetic material powder which concerns on this invention, (a) is a cross-sectional view, (b) is a vertical sectional view. It is a perspective view which shows one embodiment (the first embodiment) of the magnetic core core which concerns on this invention. It is a vertical sectional view which shows the detail of the main part of the magnetic core core. It is a schematic process diagram which shows one Embodiment of the manufacturing method of the metal strip used in this invention. It is a perspective view which shows one Embodiment of the reactor as a coil component which concerns on this invention. It is a vertical sectional view which shows the detail of the main part of the 2nd Embodiment of the magnetic core core which concerns on this invention. It is a vertical sectional view which shows the detail of the main part of the 3rd Embodiment of the magnetic core core which concerns on this invention. 6 is an SEM image taken with an electron scanning microscope (SEM) after the spheroidizing treatment in sample number 3. It is a figure which shows the relationship between Rmax of Example 1 and relative magnetic permeability. It is a figure which shows the relationship between Rmin of Example 1 and relative magnetic permeability. It is a figure which shows the relationship between Rmax of Example 1 and core loss. It is a figure which shows the relationship between Rmin and a core loss of Example 1. FIG. It is a figure which shows the relationship between the aspect ratio a / b of Example 1 and the specific magnetic permeability. It is a figure which shows the relationship between the aspect ratio a / b of Example 1 and the core loss. It is a figure which shows the relationship between Rmax of Example 2 and core loss. It is a figure which shows the relationship between Rmin and a core loss of Example 2. FIG. It is a figure which shows the relationship between the aspect ratio a / b of Example 2, and the core loss. 6 is an SEM image of sample number 21 produced in Example 3. 6 is an SEM image of sample number 22 produced in Example 4.

Next, embodiments of the present invention will be described in detail.

1A and 1B are views showing an embodiment of a particle shape of a magnetic powder used for a magnetic core according to the present invention, in which FIG. 1A is a cross-sectional view and FIG. 1B is a vertical sectional view.

In the magnetic powder of FIG. 1, for convenience of explanation, the cross-sectional shape has a circular shape, and the vertical cross-sectional shape has a constant thickness in which the four corners 1a are rounded. It has a substantially circular shape or a substantially elliptical shape, and the outer circumference has minute irregularities, and the vertical cross-sectional shape has a non-uniform thickness and varies. Therefore, in FIG. 1, the average length a in the radial direction and the average thickness b in the thickness direction indicate the arithmetic mean of the length and the thickness, respectively.

The magnetic powder 1 is three-dimensionally formed into a flat spherical surface, and has an aspect ratio a / b indicating the ratio of the average length a and the average thickness b of 1.8 to 6.8, and the angles. The portion 1a is formed in a curved surface having a radius R: 0.8 to 25 μm.

By using this magnetic material powder 1, it is possible to realize a magnetic core core having good DC superimposition characteristics and low magnetic loss. That is, this magnetic core core is manufactured by using a magnetic powder made of a pulverized metal strip as described later, but if the metal strip is simply pulverized, the edge portion of the magnetic powder is distorted. It has a sharp shape. Therefore, if the molding process is performed in a state where the edge portions of the magnetic powder are in contact with each other, the magnetic flux is concentrated on the edge portions, which may deteriorate the DC superimposition characteristic. Therefore, in order to avoid concentration of the magnetic flux on the edge portion, it is preferable to form the magnetic powder 1 in a spherical shape, and in particular, it is preferable to form the corner portion 1a in a curved surface shape.

On the other hand, when an external force is applied to the metal strip and machining including pulverization is performed for a long time, spheroidization progresses, but the magnetic powder may be greatly distorted. Such strain cannot be easily removed even if heat treatment is performed at a high temperature after machining, and the coercive force Hc of the magnetic powder 1 increases due to this strain, and as a result, the hysteresis loss increases. Therefore, the magnetic loss becomes large.

Therefore, in the present embodiment, the aspect ratio a / b of the magnetic powder 1 and the radius R of the corner portion 1a are defined as described above. The reason will be described below.

(A) Aspect ratio a / b
As described above, when the magnetic powder 1 becomes close to a spherical shape, unlike the magnetic powder having a distorted and sharp edge portion, the magnetic flux flows while diffusing on the spherical surface, so that the magnetic flux concentration can be suppressed. It is possible to improve the DC superimposition characteristics. For that purpose, it is necessary to set the aspect ratio a / b to 6.8 or less. That is, when the aspect ratio a / b exceeds 6.8, the average length a in the radial direction becomes relatively large and the average thickness b in the thickness direction becomes relatively small. Therefore, the magnetic powder 1 is extremely small. The flat shape is formed, the radius R of the corner portion 1a is also reduced, and the curved surface property of the corner portion 1a is impaired. Therefore, when a DC bias current is applied to the coil component, the magnetic flux is concentrated on the corner portion 1a, the inductance is lowered, and the DC superimposition characteristic may be deteriorated. Further, since the corner portion 1a has a sharp shape, even if the magnetic material powder 1 is to be coated with the binder as described later, it becomes difficult to uniformly cover the magnetic material powder 1 with the binder, and the insulation is insufficient. May cause an increase in magnetic loss.

On the other hand, when the aspect ratio a / b is spheroidized to less than 1.8, an external force is applied to the metal strip for a long time, so that a large strain is likely to be formed in the magnetic powder 1 after the processing. As a result, the coercive force Hc is increased, the hysteresis loss is increased, and the magnetic loss is also increased in this case.

Therefore, in the present embodiment, the aspect ratios a / b are defined as 1.8 to 6.8.

(B) Radius R of the corner portion 1a
The radius R of the corner portion 1a is also an important factor in order to avoid magnetic flux concentration while ensuring low magnetic loss. That is, when the radius R of the corner portion 1a is less than 0.8 μm, the curved surface property of the corner portion 1a is impaired, so that the magnetic flux tends to concentrate on the corner portion 1a, which causes a decrease in inductance and deteriorates the DC superimposition characteristic. There is a risk of Further, since the corner portion 1a has a sharp shape, as described above, when the magnetic powder 1 is coated with the binder, the uniformity of the coating film is impaired, the insulating property is lowered, and the magnetic loss is reduced. May lead to an increase.

On the other hand, when the radius R of the corner portion 1a exceeds 25 μm, the spheroidization of the magnetic powder 1 progresses, so that the inductance is good and the DC superimposition characteristic can be improved, but the processing for spheroidization is performed for a long time. Therefore, in this case as well, a large strain is likely to occur in the magnetic material powder 1, the coercive force Hc of the magnetic material powder 1 increases, and the hysteresis loss increases, so that the magnetic loss increases.

Therefore, in the present embodiment, the radius R of the corner portion 1a is defined as 0.8 to 25 μm.

Further, it is preferable that the magnetic powder 1 is heat-treated in a state after the spheroidizing treatment described later. That is, the magnetic powder 1 is obtained by applying an external force to the metal strip and mechanically processing it as described above. Specifically, since the magnetic powder 1 is obtained by crushing a metal strip, strain is likely to be formed in the magnetic powder 1. Since such strain causes an increase in magnetic loss, it is preferable to heat-treat the magnetic material powder 1 obtained by pulverizing the metal strip. For example, by raising the temperature to about 400 ° C. in a short time and holding it for a short time, the strain formed in the magnetic powder 1 can be efficiently removed, thereby lowering the coercive force Hc and causing a hysteresis loss. Since it can be made smaller, it is possible to further reduce the magnetic loss.

The magnetic powder 1 includes Fe—Si alloy, Fe—Si—Cr alloy, Fe—Si—Al alloy, Fe—Ni alloy, Fe—Co alloy, and Fe—Si—B—Nb. -Various crystalline alloy powder materials such as Cu-based alloys can be used, but nano-crystalline alloy powder containing Fe as the main component and a mixture of amorphous phase and nano-crystalline phase with excellent soft magnetic properties can be used. It is more preferable to use.

Here, the main component means that the Fe component is contained in 60 wt% or more, preferably 80 wt% or more in the magnetic powder 1.

The magnetic powder 1 preferably contains Fe, B, P, and Cu, and preferably contains Si and C, for example, Fe: 71 to 86 at%, B: 5 to 15 at%, and so on. P: 1 to 10 at%, Cu: 0.1 to 1.3 at%, Si: 0 to 5 at%, and C: 0 to 5 at% (however, Fe, B, P, Cu, Si, and C at each at. A magnetic powder blended so that the total of% is 100) can be used.

As a result, the desired magnetic characteristics and DC superimposition characteristics can be secured even when the amorphous phase and the nanocrystalline phase are mixed as well as the amorphous phase single phase, and the mechanical strength is low with low magnetic loss. A good magnetic core can be obtained.

The average particle size D ₅₀ of the magnetic powder 1 is not particularly limited, but it is usually possible to use the magnetic powder 1 having a diameter equivalent to a circle of 30 to 80 μm, more preferably 30 to 60 μm. can.

Then, by using this magnetic material powder 1, it is possible to obtain a magnetic core core having good DC superimposition characteristics and low magnetic loss, and further, by making the magnetic core core an embodiment shown below, the mechanical strength is improved. It becomes possible.

FIG. 2 is a perspective view showing an embodiment of the magnetic core core according to the present invention, and the magnetic core core 2 is formed in a ring shape having an elongated hole portion 2a.

FIG. 3 is a vertical cross-sectional view showing the details of the main part of the magnetic core core 2, and the main magnetic core 2 is a magnetic powder 1 and two kinds of binders (first binder 3 and second binder 4). ) And is formed of the composite material 5.

The main component of the first binder 3 is formed of a silicone resin, and the second binder 4 is formed of a resin material having a higher hardness than that of the first binder 3. The magnetic powder 1 is coated with the first binder 3, and the first binders 3 are bonded to each other via the second binder 4.

Here, the main component means that the first binder 3 contains 90 wt% or more, preferably 95 wt% or more of the silicone resin.

As a result, it is possible to obtain a magnetic core core 2 having good insulating properties, suppressing a large magnetic loss, and having good mechanical strength. That is, the silicone resin, which is the main component of the first binder 3, has excellent insulating properties and adhesiveness, and can form a strong film having Si—O bonds on the particle surface of the magnetic powder 1. .. Therefore, by coating the magnetic powder 1 with the first binder 3, it is possible to suppress the leakage of current from the magnetic powder 1, and thus it is possible to suppress the eddy current loss, whereby the magnetic loss can be suppressed. Can be reduced. Then, the first binders 3 covering the magnetic powder 1 are bonded to each other via a second binder 4 having a hardness higher than that of the first binder 3, so that the mechanical strength such as the annular strength is obtained. Can be improved, and damage can be suppressed even when a large external force is applied.

Here, the second binder 4 is not particularly limited as long as it has a higher hardness than the first binder 3, and is higher than, for example, a silicone resin (Rockwell hardness: M80 to 90). Hardness phenolic resin (Rockwell hardness: M124 to 128), polyimide resin (Rockwell hardness: M110 to 120) alone or a mixture thereof can be used.

The silicone resin is not particularly limited, but a methylphenyl-based silicone resin can be preferably used. The methylphenyl-based silicone resin has a small shrinkage rate of 0.1 to 0.2% when the composite material 5 is pressure-molded, and suppresses distortion of the magnetic powder 1 during the pressure-molding. Can be done. As a result, it is possible to suppress an increase in the holding force of the magnetic powder 1, and it is possible to avoid an increase in the hysteresis loss, so that it is possible to suppress an increase in the magnetic loss.

The content of the first binder 3 is not particularly limited as long as it can secure the desired insulating property and adhesiveness without affecting other properties, and is, for example, 0.25 to 1 wt%. It is preferably set to 0.5 to 1 wt%. If the content of the first binder 3 is less than 0.25 wt%, the content of the first binder 3 may be too small to ensure sufficient insulating properties and adhesiveness. On the other hand, if the content of the first binder 3 exceeds 1 wt%, the content of the magnetic powder 1 may be relatively reduced, which may lead to a decrease in the relative magnetic permeability.

Further, the content of the second binder 4 is not particularly limited as long as it can secure a desired mechanical strength without affecting other properties, and is, for example, 0.25 to 1 wt%. It is preferably set to 0.5 to 1 wt%. If the content of the second binder 4 is less than 0.25 wt%, the content of the second binder 4 may be too small to secure sufficient mechanical strength. On the other hand, if the content of the second binder 3 exceeds 1 wt%, the content of the magnetic powder 1 may be relatively reduced in this case as well, leading to a decrease in the relative magnetic permeability.

Further, the total contents of the first and second binders 3 and 4 are not particularly limited as long as they have good insulating properties and good mechanical strength, but are usually 1 to 1.75 wt%. Is set to. When the total content of the first and second binders 3 and 4 is less than 1 wt%, either the first binder 3 or the second binder 4 becomes too small and insulating and / or mechanical. There is a risk of reducing the target strength. On the other hand, when the total content of the first and second binders 3 and 4 exceeds 1.75 wt%, the content of the magnetic powder 1 is relatively reduced, so that the relative permeability, the magnetic flux saturation density, etc. May cause deterioration of the magnetic characteristics of.

Further, in the above embodiment, the particle surface of the magnetic powder 1 is directly coated with the first binder 3, but before the magnetic powder 1 is coated with the first binder 3, the magnetic powder 1 is coated. It is also preferable to form an insulating film having an insulating film of about 10 to 200 nm on the surface of the magnetic core core 2, whereby the insulating property of the magnetic core core 2 can be further improved. In this case, as the insulating material for forming the insulating film, a material containing phosphoric acid or Si can be preferably used.

Next, a method for manufacturing the magnetic core core will be described.

[Making a metal strip]
FIG. 4 is a diagram schematically showing one embodiment of the metal strip manufacturing step, and in this embodiment, the metal strip is manufactured by a single roll liquid quenching method.

That is, in this metal strip manufacturing step, the crucible 7 made of alumina or the like in which the metal melt 6 is housed, the induction heating coil 8 arranged on the outer periphery of the crucible 7, and the induction heating coil 8 are rotated at high speed in the direction of arrow A. It includes a roll (rotating body) 9 formed of Cu or the like, and a winding portion 11 that rotates in the direction of arrow B and winds up the metal crucible 10.

The metal strip 10 can be manufactured as follows.

First, a simple substance of each element forming an Fe-based metal magnetic material such as Fe, B, P, or Cu or a compound containing these elements is prepared as a raw material, weighed in a predetermined amount and mixed, and a high-frequency induction heating furnace or the like is prepared. It is used to heat above its melting point and then cool to obtain the mother alloy.

Next, after crushing this mother alloy, it is put into the crucible 7. Then, a high-frequency power source is applied to the induction heating coil 8 to heat the crucible 7 to melt the mother alloy, and the metal melt 6 is produced.

Next, the metal melt 6 is ejected from the nozzle 7a of the crucible 7 and dropped onto the roll 9 rotating at high speed in the direction of arrow A. As a result, the metal melt 6 is rapidly cooled and solidified by the roll 9 to form an amorphous metal strip 10, and is wound by a winding portion 11 rotating in the direction of arrow B.

[Making magnetic powder]
The metal strip 10 is heat-treated at a temperature of about 400 ° C. to precipitate a nanocrystal phase in an amorphous phase to obtain a nanocrystallized strip. Then, by pulverizing the nanocrystallized strip, high-quality magnetic powder 1 can be produced with high efficiency. That is, the coil component has good DC superimposition characteristics and low magnetic loss is required. As a magnetic powder suitable for such coil parts, a nanocrystal alloy powder in which a nanocrystal phase is precipitated in an amorphous phase is known. Conventionally, in this type of nanocrystal alloy powder, an amorphous atomized powder produced by an atomizing method is heat-treated to precipitate a nanocrystal phase in the atomized powder. However, in such a method, the heat treatment temperature of the atomized powder must be individually controlled with high accuracy, the quality tends to vary, and the productivity is also inferior.

Therefore, in the present embodiment, the metal strip 10 is heat-treated to precipitate a nanocrystal phase in the amorphous phase of the metal strip 10, so that complicated temperature control or the like is not required and the quality is high. The magnetic powder 1 can be produced with high efficiency.

Hereinafter, a method for producing the magnetic powder 1 from the metal strip 10 on which the nanocrystals are deposited, that is, the nanocrystallized strips will be described in detail.

First, the nanocrystallized strip is coarsely pulverized with a coarse pulverizer such as a feather mill (registered trademark), and then finely pulverized with an impact type pulverizer such as a pin mill until the size becomes approximately a predetermined size. Next, spheroidizing is performed using a media stirring type dry crusher such as Atwriter (registered trademark), the corner 1a is machined into a curved surface, and the average particle size D ₅₀ is converted into a circle equivalent diameter 30. A magnetic powder 1 having a curved corner portion 1a having an aspect ratio of about 80 μm, an aspect ratio a / b of 1.8 to 6.8, and a radius R of 0.8 to 25 μm is produced.

Since an external force is applied to the nanocrystallized strip for a long time, the produced magnetic powder 1 may be distorted, and the nanocrystallized strip is spheroidized as described above for the purpose of removing such strain. It is also preferable to heat-treat the treated magnetic powder 1. That is, for example, by raising the temperature to about 450 ° C. in a short time and holding it for a short time, the strain formed in the magnetic powder 1 can be efficiently removed, the coercive force Hc decreases, and hysteresis loss occurs. Since it can be suppressed, the magnetic loss can be further reduced.

[Making a magnetic core core]
A first binder 3 containing a silicone resin, preferably a methylphenyl-based silicone resin, as a main component is prepared. Next, the content of the first binder 3 in the composite material (magnetic material powder 1, first and second binders 3, 4) is preferably 0.25 to 1.0 wt%, more preferably 0. The first binder 3 is added to the above-mentioned magnetic material powder 1 so as to have a content of 5 to 1.0 wt%, and a predetermined amount of a solvent such as acetone is further added and mixed. Then, the solvent is evaporated and removed, and the surface of the magnetic powder 1 is coated with the first binder 3.

Next, a second binder 4 having a hardness higher than that of the first binder 3 such as a phenol resin or a polyimide resin is prepared. Next, the content of the second binder 4 in the composite material (magnetic powder 1, first and second binders 3, 4) is preferably 0.25 to 1.0 wt%, more preferably 0. .5 to 1.0 wt%, a magnetic material coated with the first binder 3 so that the total content of the first and second binders 3 and 4 is preferably 1 to 1,75 wt%. The second binder 4 is added to the powder 1, and a predetermined amount of a solvent such as acetone is further added and mixed. Then, the solvent is evaporated and removed, and the first binders 3 are bonded to each other via the second binder 4, whereby the composite composed of the magnetic powder 1 and the first and second binders 3 and 4 is formed. Obtain material 5.

Next, the composite material 5 is poured into the cavity of the mold, pressed to about 100 MPa and pressed, thereby producing a molded product.

After that, the molded body is taken out from the mold, and the molded body is heat-treated at a temperature of 120 to 150 ° C. for about 24 hours to cure the first and second binders 3 and 4, thereby producing a magnetic core core 2. do.

In the above embodiment, the solvent is evaporated and removed in the step of coating the magnetic powder 1 with the first binder 3, but the second binder 4 is added as it is without removing the solvent. After that, the solvent may be evaporated and removed to prepare the composite material 5.

Further, from the viewpoint of further improving the insulating property, it is also preferable to form an insulating film on the surface of the magnetic material powder 1 before coating the magnetic material powder 1 with the first binder 3 as described above. In that case, an insulating material containing phosphoric acid or Si can be used, and an insulating film can be easily formed by a known method such as a solugel method or a mechanochemical method.

FIG. 5 is a perspective view showing a reactor as an embodiment of the coil component according to the present invention, in which the coil conductor 14 is wound around the magnetic core core 2.

That is, the elongated magnetic core core 2 has two long side portions 20a and 20b parallel to each other. The coil conductor 14 is a first coil conductor (primary winding) 14a wound around one long side portion 20a and a second coil conductor (secondary winding) wound around the other long side portion 20b. The winding) 14b has a connecting portion 14c that connects the first coil conductor 14a and the second coil conductor 14b, and these are integrally formed. Specifically, in the coil conductor 14, one flat wire conducting wire made of copper or the like is coated with an insulating resin such as polyester resin or polyamide-imide resin, and one long side portion 20a of the magnetic core core 2 and It is wound in a coil shape around the other long side portion 20b.

As described above, since the coil conductor 14 is wound around the magnetic core core 2, this reactor has a high saturation magnetic flux density and a low magnetic loss, has a good mechanical strength, is ferromagnetic, and has a good softness with a small hysteresis loss. A high-purity, high-quality reactor having magnetic properties can be obtained with high efficiency.

FIG. 6 is a vertical sectional view showing the details of a main part of the second embodiment of the magnetic core core according to the present invention.

In the second embodiment, as in the first embodiment, the surface of the magnetic powder 21 is coated with the first binder 22 containing silicone as a main component, and the first binders 22 are used with each other. Is bonded via a second binder 23 such as a phenol resin having a hardness higher than that of the first binder 22. The composite material 24 is formed of the magnetic powder 21, the first and second binders 22 and 23, and the magnetic powder 21 has cracks 25 formed in 50% or more on a quantity basis. The crack 25 is filled with the first binder 22.

By forming the crack 25 in the magnetic powder 21 in this way, the strain that may occur during crushing or molding of the nanocrystallized strip is released by the crack 25, and the magnetic loss due to the strain is released. It is possible to effectively suppress the increase in. Moreover, the formation of the crack 25 improves the packing density of the magnetic powder 21, further improving the DC superimposition characteristic and reducing the magnetic loss.

The magnetic core core according to the second embodiment can be manufactured by the following method.

That is, the metal strip is heat-treated to produce a nanocrystallized strip, and the nanocrystallized strip is crushed to prepare a magnetic powder 21 by the same method and procedure as in the first embodiment described above. do.

Next, the magnetic powder 21 is heat-treated at a temperature of about 400 to 450 ° C. to increase the hardness of the magnetic powder 21 and embrittle the magnetic powder 21.

After that, the surface of the magnetic powder 21 is coated with the first binder 22 by the same method and procedure as described above, and the first binders 22 are bonded to each other via the second binder 23 to form a composite. Material 24 is made.

Next, the composite material 24 is poured into the cavity of the mold to perform pressure molding. Cracks 25 are formed in the magnetic powder 21 embrittled by this pressure molding, and the cracks 25 are filled with the first binder 22. Then, this is taken out from the mold, whereby the magnetic core core of the second embodiment in which the crack 25 is formed in the magnetic powder 21 having a quantity of 50% or more is produced.

FIG. 7 is a vertical sectional view showing the details of a main part of the third embodiment of the magnetic core core according to the present invention.

In the third embodiment, the gaps between the magnetic powders 31 are filled with fine particles 35 having an average particle size D ₅₀ of 1 to 50 μm. Like the magnetic powder 31, the fine particles 35 are made of a magnetic metal material containing Fe as a main component. Then, as in the first and second embodiments, the surface of the magnetic powder 31 is coated with the first binder 32 containing silicone as a main component, and the first binders 32 are attached to each other. It is bonded via a second binder 33 such as a phenol resin having a hardness higher than that of the binder 32. In the third embodiment, the composite material 34 is formed of the fine particles 35 in addition to the magnetic powder 31, the first and second binders 32 and 33.

The method for producing the fine particles 35 is not particularly limited, but preferably atomizing powder produced by an atomizing method, and more preferably atomizing powder produced by a water atomizing method is used. Since the water atomization method uses water for the jet fluid, unlike the gas atomization method that uses an inert gas for the jet fluid, high-pressure spraying is possible and powder particles with an average particle size D ₅₀ can be produced. Therefore, the fine particles 35 can be efficiently filled in the gaps between the magnetic powders 31 made from the metal strip 10.

By including the above-mentioned fine particles 35 in the magnetic core core in this way, since the fine particles 35 exist in the gaps between the magnetic powders 31, it is possible to further improve the DC superimposition characteristics and the specific magnetic permeability. ..

Then, the magnetic core core according to the third embodiment can be manufactured by the following method.

That is, the metal strip 10 is heat-treated to produce a nanocrystallized strip by the same method and procedure as in the first embodiment described above, and the nanocrystallized strip is crushed to obtain a magnetic powder 31. To make.

Next, a magnetic metal material containing Fe as a main component is prepared, and fine particles 35 are produced, preferably by an atomizing method, more preferably by a water atomizing method.

Next, the magnetic powder 31 and the fine particles 35 are mixed by the same method and procedure as described above, then the first binder 32 is added under a solvent, and the surface of the magnetic powder 31 is coated with the first binder 32. After coating, a second binder 33 is added, whereby the first binders 32 are bonded to each other via the second binder 33.

After that, this is poured into the cavity of the mold to perform pressure molding, and after the pressure molding, the molded body is taken out from the mold, whereby the magnetic core core of the third embodiment can be manufactured.

In this case, it is also preferable to heat-treat the magnetic powder 31 to increase the hardness and embrittlement of the magnetic powder 31 before mixing the magnetic powder 31 and the fine particles 35. As a result, as in the second embodiment, cracks are formed in the magnetic powder 31 by pressure molding, so that the strain that may occur during crushing or molding of the nanocrystallized strips is the cracks. Will be released by.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist.

In each of the above embodiments, the second binders 4, 23, 33 are formed so as to completely cover the outer surface of the first binders 3, 22, 32, but the second binder 4, 23, 33 does not have to cover the entire surface of the first binders 3, 22, 32, and the first binders 3, 22, 32 are connected to each other via the second binders 4, 23, 33. It suffices if they are joined.

Further, in the second embodiment, the magnetic material powder 21 is heat-treated before the first and second binders 22 and 23 are added to increase the hardness of the magnetic material powder 21, but the heat treatment conditions are different. By devising a method, the nanocrystalline phase may be precipitated in the amorphous phase during the heat treatment of the metal strip 10, and at the same time, the hardness may be increased.

Further, in the above embodiment, the reactor is exemplified as a coil component using magnetic powder, but it goes without saying that the reactor can be applied to other coil components, for example, an inductor.

Further, with respect to the element species constituting the magnetic powder, elements having an amorphous forming ability, such as Ga, Ge, and Pd, may be appropriately added, and trace amounts of Mn, Al, _N2 , Ti, and the like may be added. Even if it contains impurities of, it does not affect the characteristics.

Further, in the above embodiment, in the method for producing a metal strip, the formulation is heated and melted by high frequency induction heating, but the heating and melting method is not limited to high frequency induction heating, for example, by arc melting. There may be.

Next, an embodiment of the present invention will be specifically described.

[Preparation of sample]
Fe, Si _, B, and Fe 3P are prepared as raw materials, prepared to have a predetermined composition, heated to a melting point or higher in a high-frequency induction heating furnace to melt, and then the melt is made into a copper casting mold. It was poured and cooled, thereby producing a mother alloy.

Next, this mother alloy was crushed to a size of about 5 mm, put into a crucible of a single roll liquid quenching device, and subjected to high frequency induction heating to melt the mother alloy to obtain a metal melt.

Next, this metal melt was ejected from the tip nozzle of the crucible, poured into a roll rotating at high speed, and rapidly cooled and solidified, thereby producing a metal strip.

Next, this was passed through a heating furnace adjusted to a temperature of 400 ° C., and heat treatment was performed to prepare a nanocrystallized strip having a width of 50 mm and a thickness of 20 to 30 μm in which a nanocrystal phase was precipitated in an amorphous phase.

Next, the nanocrystallized strip was coarsely pulverized with a feather mill, and further finely pulverized with a pin mill until the size became approximately a predetermined size to obtain a pulverized product. Then, a dry attritor was used to spheroidize the crushed material so that the corners were curved, thereby obtaining powder samples of sample numbers 1 to 7.

Next, SEM images were taken using a scanning electron microscope (SEM) for each of 50 powder samples of sample numbers 1 to 7.

FIG. 8 shows an SEM image of sample number 3. From the SEM image as shown in FIG. 8, the average length a in the radial direction, the average thickness b in the thickness direction, and the radius R of the corners of each sample are measured, and the aspect ratio a / b and the maximum value Rmax of the radius R are measured. And the minimum value Rmin was obtained.

Next, a methylphenyl-based silicone resin (first binder) was prepared, and the silicone resin was weighed so that the content in the magnetic core core was 0.75 wt%. Then, this silicone resin was added to the powder sample, a predetermined amount of acetone was added, and the mixture was mixed. Then, acetone was evaporated and removed, and the surface of the powder sample was coated with a silicone resin.

Next, a phenol resin (second binder) was prepared, and the phenol resin was weighed so that the content in the magnetic core core was 0.75 wt%. Next, this phenol resin was added to a powder sample coated with a silicone resin, and a predetermined amount of acetone was added and mixed. Then, acetone was evaporated and removed, and the silicone resins were bonded to each other via a phenol resin to prepare composite materials of sample numbers 1 to 7.

Next, the composite material was poured into the cavity of the mold, pressed to about 100 MPa and pressed to produce a molded product. After that, the molded body is taken out from the mold, and the molded body is heat-treated at a temperature of 120 to 150 ° C. for about 24 hours to cure the silicone resin and the phenol resin, whereby the toroidal core mold samples of sample numbers 1 to 7 are sampled. (Magnetic core) was produced. The external dimensions of the prepared sample were an outer diameter of 8 mm, an inner diameter of 4 mm, and a thickness of 2.5 mm.

[Sample evaluation]
(Measurement of relative permeability)
Since the inductance and the relative permeability are in a proportional relationship, in this embodiment, the relative permeability was measured to evaluate the DC superimposition characteristic.

That is, for each of the three samples of sample numbers 1 to 7, an impedance analyzer (E4991A manufactured by KeySight Technology Co., Ltd.) was used to measure the relative magnetic permeability at a measurement frequency of 1 MHz, and the average value of each of the three samples was obtained. The DC superimposition characteristics were evaluated.

(Measurement of core loss)
For each of the three samples of sample numbers 1 to 7, the primary winding that becomes the first coil conductor is wound for 8 turns, and the secondary winding that becomes the second coil conductor is wound for 8 turns, and the BH analyzer (Iwasaki communication) Using SY-8218) manufactured by Kikai Co., Ltd., a magnetic field of 100 mT was applied at a measurement frequency of 100 kHz to measure the core loss, and the average value of each of the three samples was obtained.

(Measurement result)
Table 1 shows the aspect ratio a / b of each sample of sample numbers 1 to 7, the maximum value Rmax and the minimum value Rmin of the radius R of the corner portion, the relative permeability and the core loss.

As is clear from sample numbers 1 to 7, the degree of pulverization and the spheroidizing treatment progress in descending order. Since the degree of pulverization and the spheroidizing treatment of sample No. 1 are insufficient, the aspect ratio a / b is as large as 7.5, the Rmin value is extremely small as 0.3 μm, and the corners are sharp edges. It became a state. As a result, the relative permeability was as small as 30, and the core loss was as large as 1250 kW / m ³ . This is because the corners are formed in a sharp edge shape, so that the corners are pressure-molded in contact with each other, so that the magnetic flux is concentrated on the corners of the sample, and as a result, the relative permeability is increased. It is thought that the size became smaller and the DC superimposition characteristics deteriorated. Further, although the magnetic powder was coated with the silicone resin, it was not possible to obtain a uniform coating film, and it is considered that the eddy current loss was large and the core loss was also large.

On the other hand, sample No. 7 has an aspect ratio a / b as small as 1.2 and an Rmax value as large as 27 μm because the degree of pulverization and the spheroidizing process are excessively advanced, and is excessively close to a sphere. .. Since the magnetic flux diffuses and flows on the spherical surface without causing concentration in a specific part, the relative permeability is as large as 46, but the core loss is as large as 1700 kW / m ³ . This is because it took a long time for the pulverization process and the spheroidization process to form a sphere, which caused a large strain in the magnetic powder, which increased the coercive force Hc and increased the hysteresis loss, resulting in a large core loss. It seems that it has become.

On the other hand, sample numbers 2 to 6 have an aspect ratio a / b of 1.8 to 6.8 and a radius R of a corner portion of 0.8 to 25 μm, both of which are within the scope of the present invention. Since the magnetic flux can be diffused on the curved surface and the distortion can be suppressed without being excessively spherical, the relative permeability is as good as 38 to 49 and the core loss can be suppressed as 890 to 1120 kW / m ³ . I understood.

FIG. 9 is a diagram showing the relationship between the Rmax value and the relative magnetic permeability. In FIG. 9, the horizontal axis represents Rmax (μm) and the vertical axis represents the relative permeability (−).

As is clear from FIG. 9, it was found that the relative permeability tends to increase as Rmax increases, but decreases as shown in sample number 7 when Rmax becomes excessively large.

FIG. 10 is a diagram showing the relationship between the Rmin value and the relative magnetic permeability. In FIG. 10, the horizontal axis represents Rmin (μm) and the vertical axis represents relative permeability (−).

As is clear from FIG. 10, the relative magnetic permeability increases sharply as the Rmin increases up to about 1.5 μm (sample number 4), but when the Rmin value exceeds 1.5 μm, it tends to gradually decrease. It turned out to be.

FIG. 11 is a diagram showing the relationship between the Rmax value and the core loss. In FIG. 11, the horizontal axis represents Rmax (μm) and the vertical axis represents core loss (kW / m ³ ).

As is clear from FIG. 11, it can be seen that the core loss decreases until the Rmax value is 18 μm, but the core loss starts to increase when the Rmax value exceeds 18 μm.

FIG. 12 is a diagram showing the relationship between the Rmin value and the core loss. In FIG. 12, the horizontal axis represents Rmin (μm) and the vertical axis represents core loss (kW / m ³ ).

As is clear from FIG. 12, the core loss decreases sharply with the increase of Rmin up to about 1.5 μm, but it turns to an increasing tendency when Rmin exceeds 1.5 μm.

FIG. 13 is a diagram showing the relationship between the aspect ratio a / b and the relative magnetic permeability. In FIG. 13, the horizontal axis represents the aspect ratio a / b, and the vertical axis represents the relative permeability (−).

As is clear from FIG. 13, the relative permeability gradually increases when the aspect ratio a / b exceeds 1.2 to 2.5, but decreases when the aspect ratio a / b exceeds 2.5. You can see that it turns to.

FIG. 14 is a diagram showing the relationship between the aspect ratio a / b and the core loss. In FIG. 14, the horizontal axis shows the aspect ratio a / b, and the vertical axis shows the core loss (kW / m ³ ).

As is clear from FIG. 14, the core loss decreases sharply when the aspect ratio a / b exceeds 1.2 to 2.5, but the core loss gradually increases when the aspect ratio a / b exceeds 2.5. It turned out to turn to.

The samples had the same aspect ratios a / b, Rmax, and Rmin as those of Sample Nos. 1 to 7 prepared in Example 1, and after the spheroidizing treatment, they were put into a heating furnace for heat treatment. Specifically, the heat treatment was performed with a temperature profile of a temperature rising rate of 1 ° C./min, a maximum temperature of 400 to 425 ° C., and a holding time of 60 minutes.

After that, a composite material is produced using a silicone resin and a phenol resin by the same method and procedure as in Example 1, the composite material is pressure-molded to produce a magnetic core core, and a coil conductor is wound. Each sample of sample numbers 11 to 17 was prepared by turning.

Next, the core loss was measured for each of the three samples of sample numbers 11 to 17 by the same method and procedure as in Example 1, and the average value was obtained.

Further, the core loss of each sample of Example 1 that was not heat-treated after the spheroidizing treatment was A, and the core loss of each corresponding sample that was heat-treated after the spheroidizing treatment was B, and the core was based on the mathematical formula (1). The loss reduction rate α (%) was calculated.

α = {(AB) / A} × 100 ... (1)
Further, for sample numbers 3 and 13, the coercive force was measured using an automatic measurement coercive force meter (K-HC1000 manufactured by Tohoku Steel Co., Ltd.).

Table 2 shows the measurement results. In Table 2, the core losses of sample numbers 1 to 7 are reprinted for comparison.

As is clear from Table 2, since the sample numbers 11 to 17 were heat-treated, it was found that the core loss was reduced by 40% or more as compared with the sample numbers 1 to 7 without the heat treatment.

Further, as is clear from the comparison of sample numbers 3 and 13, the coercive force Hc was 280 A / m for the magnetic powder of sample number 3 which was not heat-treated after the spheroidizing treatment, whereas it was after the spheroidizing treatment. It was found that the heat-treated sample No. 13 reduced the amount of the magnetic powder to 100 A / m. That is, by performing the heat treatment after the spheroidizing treatment, the coercive force Hc of the magnetic powder is significantly reduced, whereby the hysteresis loss is reduced and the core loss is significantly increased from 890 kW / m ³ before the heat treatment to 510 kW / m ³ . It was found that it can be reduced to.

15 to 17 are diagrams showing the relationship between Rmax, Rmin, aspect ratio a / b and core loss in the second embodiment. In FIGS. 15 to 17, the horizontal axis shows Rmax (μm), Rmin (μm), and the aspect ratio a / b (−), respectively, and the vertical axis shows the core loss (kW / m ³ ).

As is clear from the comparison between FIGS. 15 to 17 and FIGS. 11, 12, and 14, the Rmax value, the Rmin value, the aspect ratio a / b, and the core loss have the same tendency regardless of the presence or absence of heat treatment. However, it was found that the core loss was significantly reduced by the amount that the strain was removed by performing the spheroidizing treatment.

By the same method and procedure as in Example 1, the nanocrystallized ribbon is crushed and subjected to spheroidizing treatment to obtain a magnetic powder having an aspect ratio of 5.4, an Rmax of 16 μm, and an Rmin of 1.0 μm. Fabrication was then made and then composite materials were made using silicone and phenolic resins.

Next, this composite material was held at a temperature of about 400 ° C. for a short time and heat-treated.

After that, the heat-treated composite material was pressure-molded by the same method and procedure as in Example 1 to prepare a toroidal core type sample (magnetic core core) of sample number 21.

Then, about the sample of this sample No. 21, the periphery was hardened with a resin, the annular portion was polished toward the center, and the vertical cross section was observed in a visual field region of 228 μm in length and 300 μm in width using SEM.

FIG. 18 shows the SEM image.

As is clear from FIG. 18, it was confirmed that the magnetic powder 51 had cracks 52 formed. It is considered that this is because the composite material was heat-treated before the pressure molding, so that the hardness of the magnetic powder 51 was increased and the magnetic powder 51 became embrittled, so that cracks 52 were formed during the molding process.

A magnetic powder was prepared by the same method and procedure as in Example 1.

Next, the water atomizing method was applied to prepare fine particles.

That is, a mother alloy is prepared using raw materials such as Fe, Si _, B, and Fe 3P as starting materials by the same method and procedure as in Example 1, and this mother alloy is crushed to a size of about 5 mm and water atomized. It was put into the crucible of the apparatus and subjected to high frequency induction heating to melt the mother alloy to obtain a molten metal. Next, high-pressure water of 10 to 80 MPa was sprayed onto the molten metal, pulverized and rapidly cooled to obtain fine particles having an average particle size D ₅₀ of 1 to 50 μm in terms of a circle-equivalent diameter.

Next, after mixing the magnetic powder and the fine particles, a composite material (magnetic powder, fine particles, silicone resin and phenol resin) was prepared by using the silicone resin and the phenol resin by the same method and procedure as in Example 1. ..

Next, the composite material is heat-treated by the same method and procedure as in Example 3, and then the heat-treated composite material is pressure-molded to prepare a toroidal core type sample (magnetic core core) of sample number 22. did.

Next, the vertical cross section of the sample of sample No. 22 was observed by the same method and procedure as in Example 3.

FIG. 19 shows the SEM image.

As is clear from FIG. 19, it was confirmed that the fine particles 54 were filled in the gaps between the magnetic powders 53. Therefore, it is expected that this will further improve the magnetic characteristics such as the relative permeability and the DC superimposition characteristic. Further, it was also confirmed that the crack 55 was formed in the magnetic powder 53 because the heat treatment was performed before the pressure molding as in Example 3 (see FIG. 18).

It is possible to realize a magnetic material powder having good DC superimposition characteristics and low magnetic loss, a magnetic core core, and a coil component such as a reactor using this magnetic core core.

1 Magnetic powder 1a Square part 2 Magnetic core core 3 First binder 4 Second binder 5 Composite material 6 Metal melt (melt)
10 Metal strip 14 Coil conductor 21 Magnetic material powder 22 First binder 23 Second binder 24 Composite material 25 Crack 31 Magnetic material powder 32 First binder 33 Second binder 34 Composite material 35 Fine particles

Claims (15)

A magnetic core core formed of a composite material containing a magnetic powder made of a pulverized metal strip containing at least an Fe component and a binder.
The magnetic powder is formed into a flat spherical shape, and has an aspect ratio a / b of 1.8 to 6.8, which indicates the ratio between the average length a in the radial direction and the average thickness b in the thickness direction. The corners are curved with a radius of 0.8 μm to 25 μm.
Moreover, the magnetic core powder is characterized in that cracks are formed in 50% or more on a quantity basis . The magnetic core according to claim 1 , wherein the magnetic powder contains Fe as a main component and a mixture of an amorphous phase and a nanocrystal phase. The magnetic core according to claim 1 or 2 , wherein the magnetic powder has an average particle size of 30 to 80 μm in terms of a diameter equivalent to a circle. The binder contains a first binder containing a silicone resin as a main component and a second binder composed of at least one resin having a hardness higher than that of the first binder.
Claims 1 to 3 are characterized in that the magnetic powder is coated with the first binder and the first binders are bonded to each other via the second binder. Magnetic core core on any of. The magnetic core core according to claim 4 , wherein the second binder contains at least one of a phenol resin and a polyimide resin. The magnetic core core according to claim 4 or 5 , wherein the silicone resin is a methylphenyl type. The above-mentioned composite material is characterized in that fine particles made of a magnetic metal material containing Fe as a main component having an average particle diameter of 1 to 50 μm in terms of a diameter equivalent to a circle are interposed between the magnetic powders. The magnetic core core according to any one of 1 to 6 . The magnetic core core according to claim 7 , wherein the fine particles are atomized powder. A method for manufacturing a magnetic core core made of a composite material containing a magnetic powder and a binder.
It has a magnetic powder manufacturing process and a composite material manufacturing process.
The magnetic powder manufacturing step includes a step of manufacturing a metal strip containing at least an Fe component, a step of crushing the metal strip to prepare a crushed product, and a step of spheroidizing the crushed product in the radial direction. The aspect ratio a / b indicating the ratio between the average length a and the average thickness b in the thickness direction is 1.8 to 6.8, and the corners are curved so as to have a radius of 0.8 μm to 25 μm. Including the step of producing a flat spherical magnetic powder so as to be formed.
The composite material manufacturing step includes a step of mixing the first binder containing a silicone resin as a main component and the magnetic material powder, and coating the magnetic material powder with the first binder, and the first step. A magnetic product powder coated with a binder and a second binder made of at least one kind of resin having a hardness higher than that of the first binder are mixed, and the first binders are combined with each other. A step of forming a composite material containing the magnetic powder and the first and second binders by joining via a binder of the above, and pressure molding of the composite material, the quantity of the magnetic powder is A method for manufacturing a magnetic core core, which comprises a step of manufacturing a magnetic core core so that cracks are formed in an amount of 50% or more as a reference. The method for producing a magnetic core core according to claim 9 , wherein the magnetic powder manufacturing step includes a step of heat-treating the metal strip to precipitate nanocrystals in an amorphous phase. The method for producing a magnetic core core according to claim 9 , wherein the magnetic powder manufacturing step is to heat - treat the spheroidized pulverized product. The steps for producing the metal strip include a step of weighing and blending a predetermined raw material containing at least an Fe component, a step of heating the blended formulation to prepare a melt, and a step of preparing the melt. The method for manufacturing a magnetic core core according to any one of claims 9 to 11 , further comprising a step of ejecting the metal strip onto a rotating body to quench and solidify the metal strip. The method for manufacturing a magnetic core core according to any one of claims 9 to 12 , further comprising a step of mixing the magnetic powder and fine particles made of a magnetic metal material. A coil component comprising the magnetic core core according to any one of claims 1 to 8 and a coil conductor. The coil component according to claim 14 , wherein the coil conductor is wound around the magnetic core core.

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