JP2006100848A - Compound magnetic substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin compound magnetic substance (for example, 0.4 mm or smaller) that is superior for attenuation effect at 100-400 MHz which poses problems in satisfying the EMC Standards. <P>SOLUTION: The compound magnetic substance 1 is constituted by a soft magnetic metal phase 2 and an insulation phase 3 interposed between the soft magnetic metal phases 2. Here, the soft magnetic metal phase 2 is constituted by jointing flat soft magnetic metal powder, whose surface is coated with an insulating film by pressure welding. Further, the insulating film constitutes the insulation phase 3. The compound magnetic substance 1 makes the space factor of the soft magnetic metal phase 2 to the compound magnetic substance 1 50% or higher, further to 60-90%. Further, the compound magnetic substance 1 is also made into a sheet form, having a thickness range of 5 μm-0.4 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite magnetic body used for electromagnetic noise countermeasure components in a high frequency region.

  Electronic devices such as digital electronic devices such as personal computers, game devices, and personal digital assistants are becoming more and more dense with high-frequency and high-performance circuits. It is susceptible to radiating active elements. Conventionally, radio wave absorbers compatible with ferrite cores and quasi-microwave bands have been used as countermeasures. However, with the downsizing of electronic equipment, there has been a demand for smaller, thinner, and higher performance noise countermeasure components. ing.

  On the other hand, in order to satisfy the EMC standard, meeting the noise standard in the vicinity of 100 to 400 MHz is an important issue, and the demand for radio wave absorbers and small EMI countermeasure parts corresponding to this band is increasing. In JP-A-2000-4097, flat magnetic powder is annealed to reduce residual stress, and then oriented in the in-plane direction, and in a direction perpendicular to the sheet surface at a temperature equal to or higher than the glass transition temperature Tg of the organic binder. A method of manufacturing a composite magnetic sheet that can achieve a high magnetic permeability at a frequency of 100 MHz or less by reducing the resonance frequency by applying pressure to the surface is disclosed. However, the magnetic permeability of such a composite magnetic material sheet of organic binder and flat magnetic powder is at most about 20 at 100 MHz, and it is difficult to obtain high magnetic permeability.

  Patent Document 1 discloses a method of manufacturing a powder magnetic core using flat soft magnetic powder and molding it into a plate shape by extrusion molding. This method has the advantage that the magnetic permeability can be increased because the flat soft magnetic powder is oriented in the direction of extrusion. However, when a sheet having a thickness of less than 0.4 mm is to be produced, the tension is simultaneously extruded from the narrow nozzle. It is necessary to make the film thin by adding, and it is difficult to increase the magnetic permeability. In other words, it is necessary to increase the amount of resin to reduce the viscosity at the extrusion temperature in order to give the flexibility that can be taken out when extruding from a narrow nozzle, and this reduces the filling amount of magnetic powder. High permeability cannot be obtained

A method of thinning by a printing lamination method or a doctor blade method is also disclosed without depending on extrusion. Patent Document 2 discloses that a sheet of 500 μm or less is produced by a printing lamination method using a flat soft magnetic metal powder having an aspect ratio of 5 to 40 and a binder, and this sheet is reduced to 10 mm or less. This is a method of forming a magnetic core by further press molding and punching. However, even if this method is used, since a large amount of organic binder is used in addition to the solvent, it is difficult to sufficiently increase the space factor of the soft magnetic metal powder.
Patent Document 3 discloses a method for producing a composite magnetic body in which a film is formed from a slurry-like mixture comprising flat soft magnetic powder, a binder, and a solvent. In this method, stress strain is removed. It is characterized by producing a composite magnetic body so as not to apply stress strain again to the flat soft magnetic powder, but in this method of applying no deformation stress to the flat powder itself, the space factor of the material should be increased. In addition, it is difficult to generate stress due to curing shrinkage of the resin in principle, so that high magnetic permeability cannot be expected at a high frequency around 100 MHz.

JP-A-11-74140 JP-A-11-176680 JP 2000-243615 A

All of the conventional technologies focus on reducing the residual stress of the flat soft magnetic metal powder and then giving consideration to the application of excessive stress to the flat soft magnetic metal powder in the molding process. This technical idea has the double drawback that the space factor of the metal powder cannot be increased substantially and the residual stress of the molded body does not decrease. There was a limit to the improvement of permeability.
The present invention solves this problem and provides a thin composite magnetic body (for example, 0.4 mm or less) having an excellent noise attenuation effect of 100 to 400 MHz, which is a problem when satisfying EMC standards. The purpose is to provide.

For this purpose, the present invention is a composite magnetic body comprising a soft magnetic metal phase and an insulating phase interposed between the soft magnetic metal phases, and the composite magnetic body has an insulating film formed on the surface thereof. Provided is a composite magnetic material characterized in that flat soft magnetic metal powders are pressure-bonded and laminated in layers, the insulating film forms an insulating phase, and the flat soft magnetic metal powder forms a soft magnetic metal phase To do. According to the composite magnetic body of the present invention, the space factor of the soft magnetic metal phase relative to the composite magnetic body can be 50% or more, and further 60 to 90%. In the present invention, it is desirable that the thickness of the flat soft magnetic metal powder after pressure welding is 0.1 to 1 μm. Moreover, according to this invention, a composite magnetic body can be made into the sheet form whose thickness is 5 micrometers-0.4 mm.
In the composite magnetic body according to the present invention, the insulating film preferably contains an oxide or a nitride. The oxide or nitride is preferably formed by converting perhydropolysilazane.
In addition, a resin film can be formed on the outer surface of the composite magnetic body in the present invention.

Further, the present invention is a sheet-like composite magnetic body comprising a layered soft magnetic metal phase and an insulating phase interposed between the soft magnetic metal phases, the thickness of the composite magnetic body being 5 μm to 0.4 mm, Provided is a composite magnetic body characterized in that the thickness of the soft magnetic metal phase is 0.1 to 1 μm, and the space factor of the soft magnetic metal phase in the composite magnetic body is 50% or more, and further 60 to 90%. To do. According to the composite magnetic body according to the present invention, the real part of the complex permeability at 100 MHz can be 30 or more, further 40 or more. The imaginary part of the complex permeability at 100 MHz can be 40 or more.
The present invention also provides a composite magnetic body comprising a soft magnetic metal phase and an insulating phase interposed between the soft magnetic metal phases, wherein the composite magnetic body is a flat soft magnetic metal having an insulating film formed on the surface. The powder is pressure-bonded and laminated in layers, the insulating film contains an oxide or nitride formed by conversion of perhydropolysilazane, the insulating film constitutes the insulating phase, and the flat soft magnetic metal powder is soft Provided is a composite magnetic body comprising a magnetic metal phase, wherein the composite magnetic body is a sheet having a thickness of 5 μm to 0.4 mm.
According to the present invention, there is provided a sheet-like composite magnetic material having a real part of complex permeability at 100 MHz of 40 or more, an imaginary part of complex permeability at 100 MHz of 40 or more, and a thickness of 10 μm to 0.2 mm. You can also.

In addition, the present invention provides a reinforcing composition for bonding a magnetic body having a flat soft magnetic metal powder layered with an insulating film made of oxide or nitride on the surface, and the flat soft magnetic metal powder. A composite magnetic body characterized by comprising the object is provided. Here, the reinforcing composition can be a resin film formed in a film shape on the outer surface of the magnetic body. The reinforcing composition may be a resin composition that binds flat soft magnetic metal powders inside the magnetic body.
Furthermore, the present invention is characterized in that a flat soft magnetic metal powder having a thickness of 0.1 to 1 μm is plastically deformed and closely entangled, and an insulating material is provided between the plastic soft deformed individual flat soft magnetic metal powders. A composite magnetic body is also provided. In this composite magnetic body, the insulating material contains oxide or nitride, and the space factor of the flat soft magnetic metal powder can be 50% or more.

The composite magnetic body of the present invention described above is applied in a state where an insulating film forming step for forming an insulating film on the surface of the flat soft magnetic metal powder and a flat soft magnetic metal powder having an insulating film formed on the surface are deposited. By applying pressure, it can be produced through a joining step of joining flat soft magnetic metal powders together. In this joining step, it is desirable that the flat soft magnetic metal powder is plastically deformed. Moreover, it is preferable to use for the joining process the flat soft magnetic metal powder by which the insulating film was formed in the surface classified into the range of 40-120 micrometers. By using the soft magnetic metal powder classified in this range, a sheet-like article having excellent magnetic properties can be obtained. A resin coating step of forming a resin layer on the surface of the sheet-like article obtained by the joining step can also be provided.
In addition, the composite magnetic body of the present invention includes an insulating treatment process in which a flat soft magnetic metal powder and an insulating material are mixed and insulated, and a flat soft magnetic metal powder that is insulated by mixing is deposited on the substrate and then rolled. It can be produced through a rolling orientation process in which it is oriented to form a sheet and a heat treatment process in which the sheet-like article obtained in the rolling orientation process is heat treated to relieve residual strain of the flat soft magnetic metal powder. It is effective to use an inorganic polymer perhydropolysilazane as an insulating material. A coupling agent can also be used as an insulating material. Further, one or more kinds included in an inorganic insulator such as silica sol, titania sol, magnesia sol, alumina sol, powdered glass, and boron nitride may be used as the insulating material. Before the insulation treatment step, it is effective to subject the flat soft magnetic metal powder to a heat treatment for removing strain. Further, it is desirable that the heat treatment temperature in the heat treatment step is 400 to 800 ° C., and the heat treatment atmosphere is an inert gas, nitrogen or hydrogen.

  According to the present invention, it is possible to provide a thin composite magnetic material (for example, 0.4 mm or less) having an excellent noise attenuation effect of 100 to 400 MHz, which is a problem in satisfying EMC standards, particularly high frequency. .

The present invention is characterized in that a flat soft magnetic metal powder having an insulating film formed on the surface thereof is pressure-bonded, the insulating film constitutes an insulating phase, and the flat soft magnetic metal powder constitutes a soft magnetic metal phase. A composite magnetic material is provided.
FIG. 1 schematically shows a composite magnetic body (sheet-like article) 1 in which an insulating film (insulating phase) 3 is formed on the surface of a flat soft magnetic metal powder (soft magnetic metal phase) 2.
First, the flat soft magnetic metal powder constituting the soft magnetic metal phase 2 will be described.
The flat soft magnetic metal powders are permalloy (Fe—Ni alloy), super permalloy (Fe—Ni—Mo alloy), sendust (Fe—Si—Al alloy), Fe—Si alloy, Fe—Co alloy, Fe—Cr. It is preferable that the aspect ratio is 10 to 200, more desirably 10 to 150.
The thickness of the flat soft magnetic metal powder (thickness before rolling) is preferably 0.1 to 1 μm. Setting the thickness of the flat soft magnetic metal powder to less than 0.1 μm is difficult in manufacturing and handling. Further, if the thickness of the flat soft magnetic metal powder exceeds 1 μm, it is not preferable because the magnetic characteristics at high frequencies are deteriorated. Further, even when the flat soft magnetic metal powder is pressure-welded, the thickness hardly changes. Therefore, the thickness after the flat soft magnetic metal powder is pressure-welded is also in the range of 0.1 to 1 μm.

Next, the insulating film constituting the insulating phase 3 will be described.
As shown in FIG. 1, it is ideal that the insulating film is uniformly formed on the entire surface of the flat soft magnetic metal powder, but the insulating film is formed on the surface of the flat soft magnetic metal powder. Even if there is no portion, it is sufficient that an insulating film is formed so as to function as the insulating phase 3 after the pressure welding.
An insulating film is formed on the surface of the flat soft magnetic metal powder by mixing the flat soft magnetic metal powder and the insulating material and applying a predetermined treatment. As the insulating material, an inorganic polymer-based perhydropolysilazane is preferable, and a silane-based or titanate-based coupling agent, an inorganic insulator such as silica sol, titania sol, magnesia sol, alumina sol, powder glass, boron nitride, or the like is used as the insulating material. These may also be used in combination with perhydropolysilazane.

FIG. 2 is a diagram illustrating a manufacturing process of the composite magnetic body 1 according to the present embodiment.
First, in the pulverization step, an atomized powder of soft magnetic metal having an average particle size of several tens of μm is pulverized in an organic solvent such as toluene using, for example, a stirring mill, and is flattened with a thickness of 0.1 to 1 μm and an aspect ratio of 10 to 200. A soft magnetic metal powder is obtained.
After the pulverization process, the process proceeds to a heat treatment process. In this heat treatment step, the flat soft magnetic metal powder is heat treated in an inert gas, nitrogen or hydrogen at, for example, 600 ° C. for 60 minutes. As a result, distortion due to the pulverization process for flattening the soft magnetic metal powder is removed, and oxygen and carbon mixed in the soft magnetic metal powder during pulverization are removed. Although this heat treatment step is not essential, it is preferable that the flat soft magnetic metal powder has a small distortion. Therefore, the flat soft magnetic metal powder is subjected to a heat treatment prior to the insulation treatment step described later, and the flat soft magnetic metal powder is subjected to heat treatment. It is desirable to remove the distortion of the powder.

  Next, the process proceeds to an insulating treatment process (insulating film forming process). In this process, the flat soft magnetic metal powder and the insulating material (liquid or fine powder) are mixed, the insulating film is synthesized by a predetermined method, and the insulating treatment powder, that is, the insulating film is formed on the flat soft magnetic metal powder surface. The formed powder is made. In this insulation treatment step, the treatment method differs depending on the type of insulation material. Hereinafter, (1) In case of perhydropolysilazane, (2) In case of coupling agent (silane type, titanate type, etc.), (3) In case of other oxide sol, BN (boron nitride) The processing method is described.

(1) When the insulating material is perhydropolysilazane, the flat soft magnetic metal powder and perhydropolysilazane are mixed using a mixing device. After mixing, for example, heat treatment is performed by holding at 300 ° C. for 60 minutes in air or nitrogen. Perhydropolysilazane is converted to SiO _{2 when} heat-treated in the atmosphere, and to Si ₃ N _{4 when} heat-treated in nitrogen.
(2) When the insulating material is a coupling agent (such as silane or titanate), the surface of the metal powder is coated using a wet processing method. The wet treatment is a method in which the surface treatment is performed by removing the solvent while stirring and mixing the flat soft magnetic metal powder in a coupling agent diluted 50 to 100 times with a solvent.
(3) When the insulating material is other oxide sol or BN, the flat soft magnetic metal powder and the insulating material are directly mixed (dry mixing) using a mixing device.

Then, it moves to a rolling orientation process (joining process). In the rolling orientation step, flat soft magnetic metal powders (insulating powders) on which an insulating film is formed are pressure-welded. Specifically, the insulating treatment powder is deposited almost uniformly on the substrate while sieving with a sieve, passed through a rolling roll and rolled, and the insulating treatment powder is oriented in a direction parallel to the substrate (rolling orientation step). By this step, a magnetic sheet having a thickness of 5 μm to 0.4 mm can be obtained. This sheet-shaped composite magnetic body may be punched as necessary (punching process).
In the rolling orientation step, the degree of orientation after rolling is achieved by allowing the insulating treatment powder to fall freely from a holding container such as a sieve located 3 mm or more above the substrate surface, and then rolling the insulating treatment powder after in-plane orientation. Can be improved.
Further, the magnetic properties of the finally obtained composite magnetic body can be set in an arbitrary range by appropriately selecting the mesh size of the sieve and changing the particle size of the insulating powder. A preferable range of the mesh size of the sieve is 20 to 120 μm. A more desirable range is 40 to 120 μm, and a further desirable range is 53 to 106 μm.

  The thickness of the magnetic sheet is set to 5 μm to 0.4 mm for the following reason. That is, when the thickness of the magnetic sheet is less than 5 μm, a sufficiently large magnetic permeability can be obtained at a high frequency by sintering, so the necessity for the composite magnetic body according to the present invention is small. On the other hand, when the thickness of the magnetic sheet exceeds 0.4 mm, the composite magnetic material is used in the vicinity of a narrow space where a cable shield, a portable information terminal, or a liquid crystal backlight is arranged inside the housing. It becomes difficult. Therefore, the thickness of the magnetic sheet is 5 μm to 0.4 mm. A more desirable thickness of the magnetic sheet is 10 μm to 0.2 mm. By setting the thickness of the magnetic sheet within this range, molding becomes easy and high magnetic permeability can be obtained at a high frequency.

  In addition, although the rolling orientation process (joining process) was demonstrated taking rolling as an example, this process is not restricted to rolling. Other press forming methods such as press working may be used as long as the flat soft magnetic metal powder gives a pressing force enough to cause plastic deformation, but rolling is most preferable in terms of pressurization.

Next, the punched magnetic sheet is subjected to heat treatment to relieve residual strain after plastic deformation of the flat soft magnetic metal powder (heat treatment step). In order to avoid significant oxidation of the flat soft magnetic metal powder, the heat treatment atmosphere is preferably an inert gas atmosphere such as Ar, or a nitrogen or hydrogen atmosphere.
Moreover, heat processing temperature shall be the range of 400-800 degreeC. When the heat treatment temperature is less than 400 ° C., the residual strain relaxation effect is small. On the other hand, when the heat treatment temperature exceeds 800 ° C., the insulating function of the insulating film formed on the flat soft magnetic metal powder surface is impaired. The heat treatment time may be about 1 hour.

  By passing through the above process, the sheet-like composite magnetic body (sheet-like article) 1 having a thickness of 5 μm to 0.4 mm according to the present embodiment is obtained.

Now, in the manufacturing process shown in FIG. 2, a resin coating step can be further provided after the heat treatment step. The resin coating step is performed to increase the strength of the composite magnetic body 1 and is a step of forming a resin layer on the surface (or inside) of the composite magnetic body 1.
The resin used in the resin coating step is preferably a thermoplastic resin such as butyral, acrylic, ethylcellulose, polypropylene, styrene-butadiene, or polybutylene.
In forming the resin layer on the surface of the composite magnetic body 1, a method such as impregnating the composite magnetic body 1 with a resin or spraying the composite magnetic body 1 with a resin by spraying can be appropriately employed. In the case where the composite magnetic body 1 is impregnated with a thermoplastic resin, the resin solution is prepared by diluting the thermoplastic resin with a solution of toluene, ethanol, acetone, etc., and the composite magnetic body 1 is added to the resin solution 3 to 20 What is necessary is just to impregnate about a minute.

  In some cases, the resin is impregnated inside the composite magnetic body 1, and as a result, a resin layer is not formed on the surface of the composite magnetic body 1. In this case as well, the resin is a flat soft magnetic metal inside the composite magnetic body 1. Since it functions to combine powders, the strength of the composite magnetic body 1 can be increased. Moreover, you may raise the intensity | strength of the composite magnetic body 1 using things other than resin.

  The magnetic characteristics of the composite magnetic body 1 according to the present embodiment are performed in the measurement process. The measurement results are described in the examples.

Next, the space factor of the flat soft magnetic metal powder of the composite magnetic body 1 according to the present embodiment will be described with reference to FIG.
3A and 3B are enlarged sectional views of the composite magnetic body 1 according to the present embodiment, and FIGS. 3C and 3D are enlarged sectional views of the conventional composite magnetic body.
The conventional composite magnetic material shown in FIG. 3C is composed of a flat soft magnetic metal powder and a resin (chlorinated polyethylene). Further, the conventional composite magnetic body shown in FIG. 3 (D) is obtained by press molding a mixed powder of flat soft magnetic metal powder, urethane resin, and BN powder. In the conventional composite magnetic material shown in FIGS. 3C and 3D, when the space factor of the flat soft magnetic metal powder was examined, the space factor (% by volume) was at most 40%.

On the other hand, in the composite magnetic body 1 according to the present embodiment shown in FIGS. 3A and 3B, the space factor of the flat soft magnetic metal powder was examined. In FIG. It was 87%, and the space factor was 78% in FIG. From this result, according to the composite magnetic body 1 according to the present embodiment, the space factor of the flat soft magnetic metal powder can be 50% or more, and further the occupation of the flat soft magnetic metal powder. It is estimated that the product ratio can be about 50 to 95%. A desirable range of the space factor of the flat soft magnetic metal powder is 60 to 90%, and a more desirable range is 70 to 85%. When the space factor of the flat soft magnetic metal powder is less than 50%, the magnetic properties are deteriorated. On the other hand, if the space factor of the flat soft magnetic metal powder exceeds 95%, the formability is lowered.
The composite magnetic body 1 according to the present embodiment has good magnetic properties because the space factor of the soft magnetic metal phase 2, that is, the flat soft magnetic metal powder is 50% or more. In the present embodiment, the space factor of the flat soft magnetic metal powder is a value calculated in consideration of the silicon oxide on the surface of the flat soft magnetic metal powder.

  When observing the cross section of the composite magnetic body 1 of the present embodiment, the flat soft magnetic metal powder having a thickness of 0.1 to 1 μm is plastically deformed, and the flat soft magnetic metal powder is laminated in layers. It was confirmed. Further, each flat soft magnetic metal powder has a structure insulated by an oxide or nitride. That is, it was confirmed that the composite magnetic body 1 of the present embodiment has a structure in which the insulating phase 3 is interposed between the layered soft magnetic metal phase 2. The composite magnetic body 1 of the present embodiment has a structure capable of simultaneously achieving a small demagnetizing field and a small eddy current. According to the composite magnetic body 1 of the present embodiment, the conventional composite magnetic body at 100 MHz. It is possible to achieve a complex permeability significantly greater than that of the body.

Hereinafter, the composite magnetic body of the present invention and the method for producing the same will be described in detail in Examples.
As described in the process diagram of FIG. 2, 4Mo permalloy powder (80Ni-4Mo-1Si-bal.Fe (mol%)) having an average particle diameter of about 20 μm by water atomization is used as soft magnetic metal powder, and toluene is used as a solvent. In a medium agitating mill, the powder was pulverized and flattened, and a flat soft magnetic metal powder having an average particle diameter of about 40 μm, a thickness of 0.2 to 0.6 μm, and an aspect ratio of 30 to 120 (hereinafter referred to as “flat powder” as appropriate). ). The average particle size of the powder was measured by a particle size distribution meter (Microtrack particle size distribution meter manufactured by Nikkiso Co., Ltd.) using light scattering.
Next, heat treatment was performed at 600 ° C. for 60 minutes in hydrogen to remove distortion due to pulverization for flattening the metal powder and to remove oxygen and carbon mixed in the powder during pulverization. As the insulating material, perhydropolysilazane (Tonen polysilazane L110, 20 wt% (wt%) xylene solution) was used. The amount of perhydropolysilazane 20% by weight xylene solution added to the flat Mo permalloy powder was changed to 2,3,4,5% by weight. Then, the flat Mo permalloy powder and perhydropolysilazane were mixed at room temperature for 30 minutes using a mixer (Laikai device, table kneader, etc.). Thereafter, in the air, held at 300 ° C. 60 minutes, to convert the perhydropolysilazane to SiO _2, an insulating film is formed on the surface of the flaky Mo Permalloy powder.

Next, the flat powder thus insulated was deposited on the stainless steel substrate almost evenly while sieving with a sieve (aperture: 125 μm or less) 10 mm above the stainless steel substrate. This stainless steel substrate was rolled by passing through a two-stage cold rolling roll having a roll diameter of 50 mm, and each flat powder was oriented in a direction parallel to the substrate to obtain a sheet-like article having a thickness of about 20 μm. This sheet-like article was punched into a toroidal shape and heat-treated at 600 ° C. for 60 minutes in a nitrogen atmosphere to relieve the residual strain of the flat powder after plastic deformation, and then the complex permeability (real part: μ ′, imaginary number) by the one-turn method Part: μ ″) was measured for frequency dependence. As a representative example, sample No. 3 containing 3% by weight of perhydropolysilazane was added. The μ-frequency curve of 2 is shown in FIG. 4 together with the μ-frequency curve of Comparative Example 1 without insulation treatment.
Table 1 shows the values of the complex permeability (real part: μ ′, imaginary part: μ ″) at 100 MHz for samples added with 2, 3, 4, and 5 wt%. Further, the insulation treatment of perhydropolysilazane is performed in nitrogen as well as in the atmosphere. The results are also shown in Table 1.

As shown in Table 1 and FIG. 4, the composite magnetic material sample No. 1 insulated with perhydropolysilazane was used. 1 to 5 indicate 50 μ ′ or more and 40 ″ or more μ ″ at 100 MHz. On the other hand, in Comparative Example 1 where the insulation treatment was not performed, μ ′ was 9 and μ ″ was 12 at 100 MHz, both showing insufficient values.
In addition, sample No. 1 in which the insulation treatment of perhydropolysilazane was performed in nitrogen. No. 5 and perhydropolysilazane were subjected to insulation treatment in the air. 3 is compared, sample No. 3 is compared. It was confirmed that 3 shows a better value.

Next, sample No. FIG. 5 shows the result of comparing the frequency dependence of the complex permeability of 3 (real part: μ ′, imaginary part: μ ″) with a conventional resin composite sheet punched out in the same shape. Sample No. 3 is a sample having the best characteristics in Example 1 (a sample in which the perhydropolysilazane xylene solution is 4% by weight based on the flat soft magnetic metal powder). The resin composite sheet (1) shown in FIG. 5 contains 40% by volume of flat soft magnetic metal powder, and the resin composite sheet (2) contains 30% by volume of flat soft magnetic metal powder.
Referring to FIG. It can be confirmed that No. 3 shows significantly larger complex magnetic permeability than the conventional resin composite sheet.
Sample No. As a result of cross-sectional observation by impregnating 3 with resin, as shown in FIG. 3 (B), a structure in which flat soft magnetic metal powders plastically deformed by a rolling process are laminated in layers (by way of space) A rate of 78%) was observed.

  As the soft magnetic metal powder, 2Mo permalloy powder (80Ni-2Mo-bal.Fe (mol%)) having an average particle diameter of about 30 μm by water atomization was used, and the average particle diameter was about 50 μm and the thickness was the same as in Example 1 above. It was set as the flat powder of 0.1-0.8 micrometer and aspect-ratio 10-150. Furthermore, the insulation process was performed in the same procedure, the sheet was passed through a cold rolling roll, rolled and oriented, and a sheet-like article having a thickness of about 20 μm was produced. However, the added perhydropolysilazane 20 wt% xylene solution prepared 4 wt% and 5 wt% samples with respect to the flat powder. With respect to the sample added with 4% by weight of the perhydropolysilazane solution, the sheet-like article was punched into a toroidal shape, heat-treated at 300 ° C., 600 ° C. and 900 ° C. for 60 minutes in nitrogen, and then the complex permeability (real part: μ ′, imaginary part: μ ″) was evaluated. The results are shown in Table 2 and FIG.

As shown in Table 2 and FIG. 6, the sample heat-treated at 600 ° C. (Sample No. 6) shows good characteristics, but when heat-treated at 900 ° C. (Comparative Example 3), the frequency function is lost because the insulating function is lost. Deteriorates significantly. Moreover, when heat-processed at 300 degreeC (comparative example 2), it is recognized that temperature is too low and relaxation of the residual distortion of the flat powder accompanying rolling and orientation processing to a sheet form is insufficient. Therefore, it can be said that there is a suitable range for the heat treatment.
As a result of detailed examination, it was confirmed that the heat treatment temperature range of 400 to 800 ° C., particularly preferably 450 to 700 ° C. is effective, although the range varies slightly depending on the concentration and material of the insulating material. Similarly, the sample added with the 5% by weight perhydropolysilazane solution was punched into a toroidal shape and heat-treated. Only for the heat treatment temperature of 600 ° C., the sample No. 7 is also shown in Table 2.

Looking at Table 2, sample no. 6 (heat treatment temperature: 600 ° C.) shows a good value for both μ ′ of 70 and μ ″ of 68. On the other hand, the amount of the insulating material added was sample No. In Comparative Example 2 (heat treatment temperature: 300 ° C.), which is the same as 6, μ ′ is 7 and μ ″ is 9, and in Comparative Example 3 (heat treatment temperature: 900 ° C.), μ ′ is 7 and μ ″ is 12. Sample No. A complex permeability of about 1/5 of 6 was exhibited.
In addition, Sample No. with a heat treatment temperature of 600 ° C. was used. For sample No. 7, the above-mentioned sample Similar to 6, good complex permeability was exhibited.
From the above results, it can be said that the magnetic properties of the composite magnetic body can be improved by setting the heat treatment temperature to 400 to 800 ° C.

  Using a flat 4Mo permalloy powder having an average particle size of about 40 μm produced by the same method as in Example 1, this flat 4Mo permalloy powder, BN as an insulating material, and silica sol were mixed and insulated, and then the above examples A sheet-like article having a thickness of about 30 μm was produced by passing through a cold rolling roll in the same manner as in No. 1, rolling and orienting. The sheet-like article was punched into a toroidal shape, and this was heat treated in nitrogen at 650 ° C. for 60 minutes, and then the complex permeability (real part: μ ′, imaginary part: μ ″) was evaluated. Table 3 shows the blending ratio and the obtained results.

Sample No. 8 and the magnetic characteristics of Comparative Example 1 produced in Example 1 are compared. 8 shows about 3 times higher complex permeability. However, sample no. 8 and the sample No. produced in Example 1. Comparing the magnetic characteristics of 1-4, sample no. It can be seen that 1-4 indicates better complex permeability.
From the above results, it was found that perhydropolysilazane is suitable as an insulating material.

  Using a flat 4Mo permalloy powder similar to that in Example 1, the insulating material is changed to a silane coupling agent and a titanate coupling agent, and cold rolling is performed in the same manner as in Example 1 to obtain a sheet-like article of about 25 μm. And punched into a toroidal shape. Thereafter, heat treatment was performed, and the complex permeability at 100 MHz of the sample was measured. The results are shown in Table 4 together with the compounding ratio and heat treatment conditions. The insulation treatment with the coupling agent was performed by a known wet method.

  Looking at Table 4, sample no. Nos. 9 and 10 are good values when μ ′ is 30 or more and μ ″ is 40 or more. Therefore, it was found that silane coupling agents and titanate coupling agents can also be suitably used as insulating materials.

  Further, the same flat 4Mo permalloy powder as in Example 1 was used, insulation treatment was performed with perhydropolysilazane, mixed with silica sol, and cold-rolled by the same method as in Example 1 to obtain a sheet-like article of about 25 μm. It was. A sheet-shaped article was punched, and then the complex permeability at 100 MHz of the heat-treated sample was measured. The results are shown in Table 5 together with the blending ratio and heat treatment conditions. Table 5 also shows the values of the complex magnetic permeability at 100 MHz of the resin composite sheet (1) and the resin composite sheet (2) shown in FIG.

  When Table 5 is seen, sample No. is compared with the comparative examples 4 and 5 of the conventional resin composite sheet. It can be seen that 11 shows remarkably excellent complex permeability (real part: μ ′, imaginary part: μ ″). Therefore, it was confirmed that a method of performing insulation treatment with perhydropolysilazane and further mixing with silica sol was also effective.

A 2Mo permalloy powder having an average particle size of about 30 μm by water atomization is used as the soft magnetic metal powder, and the average particle size is about 130 μm, the thickness is 0.1 to 0.8 μm, and the aspect ratio is 10 to 150 by the same method as in Example 1 above. A flat powder was obtained. Further, 4% by weight of a 20% by weight xylene solution of perhydropolysilazane was added to the flat powder to perform insulation treatment.
Next, nine kinds of classified powders were obtained from the flat powder (insulated powder) subjected to insulation treatment using sieves having various mesh sizes as follows. These classified powders were passed through a cold rolling roll, rolled and oriented to produce a sheet-like article having a thickness of about 20 μm. This sheet-like article was punched into a toroidal shape, and after heat treatment in nitrogen at 500 ° C. for 60 minutes, the complex permeability (real part: μ ′, imaginary part: μ ″) was measured. The result is shown in FIG.
Classification powder (μm): 20-32, 32-38, 38-45, 45-53, 53-63, 63-75, 75-90, 90-106, 106 under

As shown in FIG. 7, the magnetic properties vary depending on the classification size of the flat powder, that is, the particle size. For example, when 20-45 μm classified powder is used, μ ′ at 100 MHz can be about 30-60. Further, when a classified powder of 45 to 106 μm is used, μ ′ at 100 MHz can be set to 60 or more. In particular, when 63-106 μm classified powder is used, it is noted that μ ′ at 100 MHz is 80 or more.
Moreover, when using 45-106 micrometer classification | category powder, it was confirmed that (micro | micron | mu) '' in 100 MHz also shows the favorable value of 60 or more.
From the above results, it was found that a composite magnetic material having good magnetic properties can be obtained by setting the particle size of the flat powder to about 40 to 120 μm.

A 2Mo permalloy powder having an average particle size of about 30 μm by water atomization is used as the soft magnetic metal powder, and the average particle size is about 130 μm, the thickness is 0.1 to 0.8 μm, and the aspect ratio is 10 to 150 by the same method as in Example 1 above. A flat powder was obtained.
Further, 4% by weight of a perhydropolysilazane 20% by weight xylene solution was added to the flat powder for insulation treatment.
Next, the flat powder subjected to insulation treatment was classified with a sieve having a mesh size of 38 μm and 63 μm. These classified powders were passed through a cold rolling roll, rolled and oriented to produce a sheet-like article having a thickness of about 20 μm. The sheet-like article was punched into a toroidal shape, and after heat treatment at 500 ° C. for 60 minutes in nitrogen, the complex permeability (real part: μ ′, imaginary part: μ ″) was measured.
As a comparative example, a sheet-like article having a thickness of about 20 μm was obtained by the same process as above except that 2Mo permalloy powder having an average particle diameter of about 50 μm by water atomization was used as the soft magnetic metal powder. The magnetic properties were measured. The result is shown in FIG. In addition, when the sheet-like article by a comparative example was observed, it was confirmed that the state of the powder of the irregular shape by water atomization is maintained after rolling.

As shown in FIG. 8, when flat powder is used at 1 to 10 MHz, μ ′ is 4 to 5 times that when non-flat powder is used. At 100 MHz, μ ′ when a non-flat powder was used showed a value in the vicinity of 20, whereas when flat powder was used, μ ′ showed a value of 40 or more.
It was also confirmed that when flat powder was used, the rise and peak values of μ ″ shifted to the higher frequency side than when non-flat powder was used.
From the above results, it has been found that a composite magnetic material having significantly improved magnetic properties can be obtained by using flat powder.

Using 2Mo permalloy powder having an average particle diameter of about 30 μm by water atomization as the soft magnetic metal atomized powder, the average particle diameter is about 130 μm, the thickness is 0.1 to 0.8 μm, and the aspect ratio is 10 to 10 by the same method as in Example 1 above. 150 flat powders were obtained. Further, 4% by weight of a 20% by weight xylene solution of perhydropolysilazane was added to the flat powder to perform insulation treatment.
Next, the two-stage cold rolling with a roll diameter of 50 mm is performed by depositing the insulated flat powder on the stainless steel substrate almost uniformly while sieving with a sieve (opening; 106 μm or less) 10 mm above the stainless steel substrate. The sheet was rolled through a roll, and each flat powder was oriented in a direction parallel to the substrate to obtain a sheet-like article having a thickness of about 20 μm. This sheet-like article was punched into a toroidal shape and heat-treated at 500 ° C. for 60 minutes in nitrogen.
Subsequently, 10 types of thermoplastic resins (resins A to J) were each adjusted to 5 wt% with toluene to prepare 10 types of resin solutions. Using this resin solution, a resin coating treatment was performed on the sheet-like composite magnetic body (the sheet-like composite magnetic body was immersed in the resin solution for 15 minutes and then dried at room temperature). The result of the strength test performed thereafter is shown in FIG.

As shown in FIG. Nos. 13 to 22 are sample Nos. That were not subjected to resin coating treatment for both stress and elongation. The value of 12 is exceeded. In particular, sample Nos. 1 and 2 were impregnated with butyral and acrylic resins. Nos. 15, 17 to 19 and 21 are sample Nos. 12 is 2.5 to 5 times larger than the sample No. 12, and the elongation is the same as that of Sample No. The value of 1.5 to 4.5 times 12 was shown.
From the above results, it was found that the strength of the composite magnetic body can be improved by applying a resin coating treatment to the composite magnetic body. Further, it was confirmed that the coated resin bound flat soft magnetic metal powders constituting the composite magnetic body.

Sample No. 12 and sample no. When the magnetic characteristics of 13 to 22 were compared, all showed the same magnetic characteristics. Therefore, it can be said that the magnetic characteristics do not change even when the resin coating treatment is applied to the composite magnetic body.
Furthermore, sample no. When the thicknesses of 13 to 22 were measured, some of the samples were sample Nos. The same thickness as 12 was shown. That is, since the voids exist inside the composite magnetic body, it is suggested that the resin is impregnated in the voids.

  Although the embodiments and examples of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited thereto and various modifications and changes can be made within the scope of the claims. I will.

  As described above, according to the present invention, it has a complex permeability higher than that of a conventional magnetic material and resin composite sheet in a high frequency region, particularly in a frequency region of 100 to 400 MHz, which is a problem in satisfying the EMC standard. Moreover, since it can satisfy | fill simultaneously that it is set as thickness of 0.4 mm or less to a sheet form, EMI countermeasure components can be reduced in size. The composite magnetic body of the present invention can be suitably used, for example, in a narrow space where a cable shield, a portable information terminal, or a liquid crystal backlight is disposed.

It is a schematic diagram which shows the state by which the insulating film (insulating phase) was formed in the surface of flat soft magnetic metal powder (soft magnetic metal phase). It is a manufacturing-process figure which concerns on embodiment of this invention. The expanded cross section of the composite magnetic body which concerns on this invention is shown in contrast with the conventional composite magnetic body, (A) is an expanded sectional view of the composite magnetic body of this invention (space factor 87%), (B) is this invention. (C) is an enlarged cross-sectional view of a conventional composite magnetic body made of flat soft magnetic metal powder and resin (chlorinated polyethylene), and (D) is a flat view. It is an expanded sectional view of the composite magnetic body which press-molded the mixed powder of the soft magnetic metal powder, urethane resin, and BN powder. According to Example 1 of the present invention, the frequency dependence of the complex magnetic permeability of a composite magnetic material sample having a thickness of 20 μm using 3% by weight of a perhydropolysilazane solution is obtained when the flat soft magnetic metal powder is not insulated. It is a graph shown by contrast. The graph which shows the frequency dependence of the complex magnetic permeability of the composite magnetic material sample of 20 micrometers in thickness using 4 weight% of perhydropolysilazane solutions based on Example 1 of this invention with the case of the conventional resin composite sheet. It is. It is a graph which shows the frequency dependence of the complex magnetic permeability of the composite magnetic body sample of 20 micrometers in thickness using 4 weight% of perhydropolysilazane solutions based on Example 2 of this invention, changing heat processing temperature. It is a graph which shows the frequency dependence of the complex magnetic permeability of the composite magnetic material sample produced using nine types of classified powder based on Example 6 of this invention. It is a graph which shows the frequency dependence of the complex magnetic permeability of the composite magnetic material sample using the flat powder according to Example 7 of the present invention as compared with the case of using the non-flat powder. It is a graph which shows the result of the strength test of the sheet-like composite magnetic body which performed the resin coat process based on Example 8 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Composite magnetic body (sheet-like article), 2 ... Soft magnetic metal phase (flat soft magnetic metal powder), 3 ... Insulating phase (insulating film)

Claims (15)

A soft magnetic metal phase,
A composite magnetic body comprising an insulating phase interposed between the soft magnetic metal phases,
The composite magnetic body is
A flat soft magnetic metal powder with an insulating film formed on the surface is pressure-welded and laminated in layers,
The composite magnetic body, wherein the insulating film constitutes the insulating phase, and the flat soft magnetic metal powder constitutes the soft magnetic metal phase.   2. The composite magnetic body according to claim 1, wherein a space factor of the soft magnetic metal phase with respect to the composite magnetic body is 60 to 90%.   3. The composite magnetic body according to claim 1, wherein the flat soft magnetic metal powder has a thickness of 0.1 to 1 μm after being pressure-welded. 4.   The composite magnetic body according to claim 1, wherein the composite magnetic body has a sheet shape with a thickness of 5 μm to 0.4 mm.   5. The composite magnetic body according to claim 1, wherein the flat soft magnetic metal powder is permalloy or super permalloy.   The composite magnetic body according to claim 1, wherein the insulating film includes an oxide or a nitride formed by converting perhydropolysilazane.   The composite magnetic body according to claim 1, wherein a resin film is formed on an outer surface of the composite magnetic body. A layered soft magnetic metal phase;
A sheet-like composite magnetic body comprising an insulating phase interposed between the soft magnetic metal phases,
The thickness of the composite magnetic material is 5 μm to 0.4 mm,
The soft magnetic metal phase has a thickness of 0.1 to 1 μm,
A composite magnetic body, wherein a space factor of the soft magnetic metal phase in the composite magnetic body is 60 to 90%.   The composite magnetic body according to claim 8, wherein the soft magnetic metal phase is composed of a plastically deformed flat soft magnetic metal powder.   The composite magnetic body according to claim 8 or 9, wherein the real part of the complex permeability at 100 MHz is 30 or more.   The composite magnetic body according to claim 8 or 9, wherein a real part of complex permeability at 100 MHz is 40 or more.   12. The composite magnetic body according to claim 8, wherein the imaginary part of the complex permeability at 100 MHz is 40 or more. A soft magnetic metal phase,
A composite magnetic body comprising an insulating phase interposed between the soft magnetic metal phases,
The composite magnetic body is
A flat soft magnetic metal powder with an insulating film formed on the surface is pressure-welded and laminated in layers,
The insulating film includes an oxide or nitride formed by converting perhydropolysilazane, the insulating film constitutes the insulating phase, and the flat soft magnetic metal powder constitutes the soft magnetic metal phase. ,
The composite magnetic body is a sheet having a thickness of 5 μm to 0.4 mm.   The composite magnetic body according to claim 13, wherein the real part of the complex permeability at 100 MHz is 40 or more and the imaginary part of the complex permeability at 100 MHz is 40 or more.   The composite magnetic body according to claim 13 or 14, wherein the composite magnetic body has a sheet shape with a thickness of 10 µm to 0.2 mm.

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