JP2022060858A - Manufacturing method of composite magnetic body - Google Patents

Abstract

To provide a manufacturing method of a composite magnetic body, the method enabling a composite magnetic body having excellent magnetic properties to be easily obtained.SOLUTION: There is provided a manufacturing method of a composite magnetic body in which a flat metal powder 10 is oriented and dispersed in a binder 11, the method includes the steps of: crushing a magnetic body to obtain a flat metal powder 10, charging the flat metal powder 10 into a molding die 20; applying vibrating force that vibrates in the horizontal direction orthogonal to the direction of gravity to the flat metal powder 10; and impregnating the binder 11 between the flat metal powders 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a composite magnetic material.

As a magnetic component used in an electronic circuit, a composite magnetic core in which a magnetic metal powder is oriented and dispersed in a binder such as a resin is used as a magnetic core. In such a composite magnetic material, in order to improve the magnetic permeability characteristic, the metal powder is processed into a flat shape and molded at a high density to improve the magnetic flux density. Further, with the increasing functionality of electronic devices, the operating frequency of magnetic parts has been increased. For example, in inductor elements such as reactors, choke coils, and transformers, there is a demand for a magnetic core material having excellent magnetic characteristics in a region where the operating frequency is higher. Further, since such a magnetic core needs to be formed to various thicknesses depending on the application, a manufacturing method having a high degree of freedom in shape is required.

Patent Document 1 discloses a sheet-shaped inductor, an inductor with a built-in laminated substrate, and a method for manufacturing the same. The sheet-shaped inductor described in Patent Document 1 has a magnetic core and a coil, and is provided with first and second via holes that penetrate the two facing surfaces of the magnetic core in the stacking direction, respectively. The coil has first and second via conductors formed so that their ends project outward from the first and second via holes, and plug portions at both ends of the first and second via conductors. It has first and second surface conductors joined via. The magnetic core is a mixture containing a flat metal powder having soft magnetism and a binder, and the soft magnetic flat metal powder is made of a sheet oriented and molded in a plane formed by the inductor, or the sheet is formed. A plurality of sheets are laminated and pressed in the stacking direction. The inductor with a built-in laminated board has a magnetic core built in the laminated board.

Japanese Unexamined Patent Publication No. 2013-243330

However, in order to obtain a thick composite magnetic material by the manufacturing method described in Patent Document 1, a plurality of sheet-shaped magnetic cores must be laminated and pressurized. Therefore, when a composite magnetic material requiring a thickness is manufactured by such a method, there is a problem that the number of steps and the manufacturing equipment used are large and complicated.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a method for producing a composite magnetic material, which can easily obtain a composite magnetic material having excellent magnetic properties. be.

The method for producing a composite magnetic material according to one embodiment is a method for producing a composite magnetic material in which a flat metal powder is oriented and dispersed in a binder, and includes a step of crushing the magnetic material to obtain a flat metal powder. It has a step of charging the flat metal powder into a molding die, a step of applying a vibrating force vibrating in the horizontal direction orthogonal to the direction of gravity to the flat metal powder, and a step of impregnating the flat metal powder with a binder.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for producing a composite magnetic material, which can easily obtain a composite magnetic material having excellent magnetic properties.

It is a flowchart which shows the manufacturing method of the composite magnetic material which concerns on Embodiment 1. It is a photograph which shows the flat metal powder obtained by the pulverization step in the manufacturing method of the composite magnetic material which concerns on Embodiment 1. FIG. It is a figure which shows the charging process in the manufacturing method of the composite magnetic material which concerns on Embodiment 1. FIG. It is a figure which shows the vibration process in the manufacturing method of the composite magnetic material which concerns on Embodiment 1. FIG. It is a figure which shows the impregnation process in the manufacturing method of the composite magnetic material which concerns on Embodiment 1. FIG. It is a photograph which shows the composite magnetic material which concerns on Example. It is a photograph which shows the composite magnetic material which concerns on Comparative Example 1. It is a photograph which shows the composite magnetic material which concerns on Comparative Example 2. It is a graph which shows the vibration condition of the vibration process in the manufacturing method of the composite magnetic material which concerns on Embodiment 1. FIG.

Embodiment 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Further, in order to clarify the explanation, the following description and drawings are appropriately simplified. The composite magnetic material according to the present embodiment is a composite magnetic material in which magnetic metal powder is oriented and dispersed in a binder and is formed into a thick bulk like a magnetic core constituting a reactor, for example.

First, a method for manufacturing a composite magnetic material according to the present embodiment will be described with reference to FIGS. 1 to 5. FIG. 1 is a flowchart showing a method for manufacturing a composite magnetic material according to the first embodiment. As shown in FIG. 1, the method for producing a composite magnetic material according to the first embodiment includes four steps S1 to S4.

In the pulverization step of step S1, the magnetic material is pulverized to obtain a flat metal powder. In the charging step of step S2, the obtained flat metal powder is charged into the molding die. In the vibration step of step S3, a vibration force vibrating in the horizontal direction orthogonal to the direction of gravity is applied to the flat metal powder. In the impregnation step of step S4, the binder is impregnated between the flat metal powders in the molding die.

Subsequently, each step described with reference to FIG. 1 will be described in detail. First, the magnetic material used in the pulverization step of step S1 will be described. Examples of the magnetic material for the magnetic core include alloys having various known compositions such as pure iron, Fe—Ni alloys, Fe—Si alloys, Fe—Si—Al alloys, and Fe—Cr—Si alloys. , Amorphous alloys, nanocrystalline alloys, etc., but are not limited thereto.

In this embodiment, a method for producing a composite magnetic material when an amorphous alloy is used will be described. Amorphous alloys are soft magnetic materials made by adding elements such as silicon, chromium, copper, aluminum, titanium, zirconium, and niob to ferromagnetic elements such as iron, cobalt, and nickel. For example, an iron-based amorphous alloy is particularly suitable for a magnetic core of an inductor element because it has a high saturation magnetic flux density and low loss.

The amorphous alloy can be pulverized into a flat shape by a pulverization method or an atomization method. However, there is a problem that the atomized powder obtained by the atomizing method is expensive. On the other hand, the pulverized powder of an amorphous alloy obtained by the pulverization method can be inexpensively produced by taking the following means, and good magnetic properties can be easily obtained. Therefore, it is preferable to pulverize the amorphous alloy by a pulverization method.

As a magnetic material made of an amorphous alloy, an amorphous ribbon is obtained by thinning a molten alloy having various known compositions by a high-speed quenching method using a single-roll type manufacturing device or a double-roll type manufacturing device. be. Amorphous ribbon crushed powder has excellent magnetic properties and can be produced at a lower cost than amorphous alloy atomized powder. For example, when the amorphous ribbon is used in another manufacturing process, if the scrap material of the amorphous ribbon generated in another manufacturing process is applied as the magnetic material of the composite magnetic material manufacturing method according to the present embodiment, the material cost is further increased. It is possible to reduce it.

FIG. 2 is a photograph showing a flat metal powder obtained by a pulverization step in the method for producing a composite magnetic material according to the first embodiment. FIG. 2 shows crushed powder obtained by crushing an amorphous ribbon with a crusher. When a magnetic material made of an amorphous alloy is used, it is preferable that a heat treatment for embrittlement is performed before pulverization. Then, the magnetic material is roughly pulverized by a cutter mill or the like and then finely pulverized by using an impact type pulverizer such as a sample mill to produce the flat metal powder 10 shown in FIG. 2.

The finely pulverized pulverized powder can also be classified using, for example, a sieve to obtain a flat metal powder 10 having a desired particle size. The flat metal powder 10 thus produced has at least one main surface and is formed as a flat powder having a major axis and a minor axis. Further, the flat metal powder 10 obtained by pulverization may be subjected to heat treatment or the like for the purpose of improving magnetic properties and forming an insulating film, if necessary.

For crushing the magnetic material, various crushers such as an attritor, a stamp mill, a ball mill, a vibrating ball mill, a cyclone mill, and a jet mill can be used. The pulverization method is not particularly limited as long as the magnetic material can be formed into a powder having a desired shape, particle size, and aspect ratio. The shape, particle size, and aspect ratio of the flat metal powder 10 are not particularly limited, and may be appropriately designed in consideration of the density, magnetic loss, and the like of the obtained composite magnetic material M.

In the charging step of step S2, a molding die is prepared. FIG. 3 is a diagram showing a charging step in the method for manufacturing a composite magnetic material according to the first embodiment. Since the molding die 20 used in step S2 can also be used as an outer case for the magnetic component to be manufactured, it is preferable that at least a part thereof is made of a metal having high thermal conductivity. Further, at least a part thereof may be made of resin. As the shape of the molding die 20, various shapes can be used according to the shape required for the magnetic component to be manufactured. The mold 20 is formed with an opening 21 for charging and injecting the flat metal powder 10 and the binder 11. The flat metal powder 10 obtained in step S1 is charged from the opening 21 of the prepared molding die 20, and the flat metal powder 10 is filled in the molding die 20.

In the vibration step of step S3, a vibration force is applied to the molding die 20 into which the flat metal powder 10 is charged in step S2. FIG. 4 is a diagram showing a vibration process in the method for manufacturing a composite magnetic material according to the first embodiment. As shown in FIG. 4, in step S3, for example, it is preferable to close the opening 21 of the molding die 20 with the lid material 22, and if necessary, a weight or the like is placed on the lid material 22 to adjust the load. You may. The surface pressure acting on the flat metal powder 10 in the mold 20 is a relatively small surface pressure so that the flat metal powder 10 to which the vibration force is applied can freely change its direction in the mold 20. In the present embodiment, for example, the composite magnetic material M can be manufactured by pressurizing the lid material 22 to the extent of its own weight. Therefore, high surface pressure pressurization using a pressurizing device or the like is not required.

Further, in the vibration step, the vibration direction for vibrating the molding die 20 is a horizontal direction orthogonal to the gravity direction, and the mold 20 is vibrated so as to reciprocate along a specific direction. As a method of applying vibration to the mold 20, it is preferable to use a vibration device capable of applying high frequency vibration to the mold 20. The molding die 20 set in the vibrating device vibrates in the left-right direction indicated by the white arrow in FIG. 4 due to the vibration generated by the vibrating device.

In this way, by applying vibration to the molding die 20 into which the flat metal powder 10 is charged, the long axis direction of the flat metal powder 10 is oriented in the vibration direction. Further, the gap between the flat metal powders 10 is reduced by the vibration, so that the packing density of the flat metal powders 10 in the mold 20 is improved. As a result, the saturation magnetic flux density and the magnetic permeability of the composite magnetic body M manufactured by the method for manufacturing the composite magnetic body according to the present embodiment are improved.

In the impregnation step of step S4, the liquid binder 11 is injected into the flat metal powder 10 filled in the molding die 20. FIG. 5 is a diagram showing an impregnation step in the method for producing a composite magnetic material according to the first embodiment. As shown in FIG. 5, the injected binder 11 is impregnated between the mold 20 and the flat metal powder 10 and between the flat metal powder 10. Then, by curing the binder 11, the composite magnetic material M is produced.

As the binder 11 used at this time, a known insulating material used for producing a composite magnetic material such as a thermosetting resin or a thermoplastic resin can be used. It is preferable that the binder 11 to be used is impregnated by appropriately adjusting the viscosity so that it can be smoothly impregnated between the flat metal powders 10 whose packing density has been improved by high-frequency vibration. Further, as the curing method of the binder 11, an appropriate temperature and curing conditions are selected according to the curing characteristics of the binder 11 to be used. Further, the injection amount of the binder 11 is an appropriate amount in consideration of the density, strength, insulating property and the like of the obtained composite magnetic material M.

By the above steps S1 to S4, the composite magnetic material M in which the flat metal powder 10 is oriented and dispersed in the binder 11 is produced. Further, by winding a coil around the composite magnetic material M, magnetic material parts such as an inductor, a reactor, a choke coil, and a transformer can be manufactured. The composite magnetic material M can also be taken out from the molding die 20 and used.

Next, the results of verification of the vibration direction and vibration conditions that affect the orientation of the flat metal powder and the density of the composite magnetic material in steps S1 to S4 will be described based on Examples and Comparative Examples.

First, with reference to FIGS. 6 to 8, the influence of the vibration direction in the vibration step of step S3 on the orientation of the flat metal powder 10 will be described. FIG. 6 is a photograph showing the composite magnetic material according to the embodiment. FIG. 7 is a photograph showing the composite magnetic material according to Comparative Example 1. FIG. 8 is a photograph showing the composite magnetic material according to Comparative Example 2. In order to verify the influence of the vibration direction on the orientation of the flat metal powder 10, by vibrating in different vibration directions, the three types of composite magnetic materials M1 of Example, Comparative Example 1 and Comparative Example 2 are applied. , M2, M3 were manufactured.

The composite magnetic body M1 according to the embodiment is a composite magnetic body M1 manufactured according to the method for manufacturing the composite magnetic body according to the present embodiment, and the vibration direction in the vibration step (step S3) is a horizontal direction orthogonal to the gravity direction. (Left and right in the drawing). As shown in FIG. 6, when the molding die 20 into which the flat metal powder 10 is charged is subjected to horizontal vibration, in the obtained composite magnetic material M1, many flat metal powders 10 have a length thereof. It is in a state of being oriented in the left-right direction in which the axial direction is the vibration direction. Further, the composite magnetic material M1 according to the examples has fewer voids formed between the flat metal powders 10 and is formed at a higher density than the composite magnetic materials M2 and M3 according to Comparative Examples 1 and 2. You can see that it is.

In the composite magnetic material M2 according to Comparative Example 1, the flat metal powder 10 obtained in the pulverization step (step S1) and the binder 11 are mixed and stirred in the mold 20 and then bonded after the flat metal powder 10 is precipitated. It is a composite magnetic material M2 produced by curing the agent 11. In the manufacturing process of Comparative Example 1, since the vibration step was omitted, the molding die 20 containing the flat metal powder 10 was not vibrated. As shown in FIG. 7, when the molding die 20 containing the flat metal powder 10 is not vibrated, the flat metal powder 10 faces in different directions in the obtained composite magnetic material M2. Yes, not oriented in a particular direction.

The composite magnetic material M3 according to Comparative Example 2 has a vibration direction in the gravity direction (drawing) with respect to the molding die 20 into which the flat metal powder 10 obtained in the crushing step (step S1) and the charging step (step S2) is charged. In the vertical direction), high-frequency vibration was applied. After that, it is a composite magnetic material M3 produced by impregnating and curing the binder 11 between the flat metal powders 10. The composite magnetic material M3 is manufactured by the same method as the composite magnetic material M1 except for the vibration direction. As shown in FIG. 8, when the molding die 20 into which the flat metal powder 10 is charged is vibrated in the direction of gravity, the flat metal powder 10 is not convected in the obtained composite magnetic material M3. It is in a uniform direction and is not oriented in a specific direction. It is considered that when a vibration force in the direction of gravity is applied to the flat metal powder 10, the flat metal powder 10 freely moves in the mold 20 and changes its direction in various directions.

As described above, in the composite magnetic material M1, the easy magnetization directions of the flat metal powder 10 are aligned with the vibration direction. Further, the packing density of the flat metal powder 10 is improved, and the density of the composite magnetic material M1 is increased. As a result, in the composite magnetic material M1 according to the embodiment, a high saturation magnetic flux density and a high magnetic permeability can be obtained.

On the other hand, in the composite magnetic materials M2 and M3, the easy magnetization direction of the flat metal powder 10 tends to be a non-uniform direction, so that the magnetic fluxes cancel each other out and the magnetic flux density decreases. Further, in the composite magnetic materials M2 and M3, the proportion of the voids is high, so that the packing density of the flat metal powder 10 is lowered. Therefore, the composite magnetic flux densities and magnetic permeability of the composite magnetic materials M2 and M3 according to Comparative Example 1 and Comparative Example 2 are lower than those of the composite magnetic material M1 according to Example 1.

Subsequently, with reference to FIG. 9, the influence of the vibration conditions in the vibration step of step S3 on the density of the composite magnetic material M manufactured by the method for manufacturing the composite magnetic material according to the present embodiment will be described. FIG. 9 is a graph showing the vibration conditions of the vibration process in the method for manufacturing the composite magnetic material according to the first embodiment.

As shown in FIG. 9, the flat metal powder 10 is charged using vibration conditions of a plurality of frequencies having different amplitudes of around 510 μm, around 300 μm, and around 90 μm, and vibration conditions of a frequency of 15,000 Hz for an amplitude of 34 μm. The composite magnetic body M was manufactured by applying a vibration force to the molded mold 20. Then, when the densities of each of the obtained composite magnetic materials M were compared, it was found that the density of the composite magnetic material M increased as the frequency increased.

For example, when vibrated under vibration conditions having an amplitude of 90.9 μm and a frequency of 211 Hz, the density of the obtained composite magnetic material M was 3.6 g / cm ³ . Further, when vibrated under vibration conditions having an amplitude of 34.0 μm and a frequency of 15,000 Hz, the density of the obtained composite magnetic material M is 4.4 g / cm ³ , which is the highest density of the composite magnetism among the verified vibration conditions. I was able to get a body M.

For example, in the case of producing a high-density magnetic core (composite magnetic material) by the method described in Patent Document 1, a flat metal powder is produced, and then a slurry forming device, a heating device, a laminating device, a pressurizing device, or the like is used. It needs to be processed using manufacturing equipment. Therefore, in the method described in Patent Document 1, the number of processes and manufacturing equipment are complicated, and there is a risk of high cost. In addition, excessive stress is applied to the flat metal powder due to pressurization, and strain is introduced, so that the coercive force of the flat metal powder increases and the magnetic permeability decreases, which may lead to deterioration of the performance of the composite magnetic material. ..

On the other hand, in the method for producing a composite magnetic material according to the present embodiment, the orientation of the flat metal powder is improved by applying a horizontal vibration force to the flat metal powder obtained by crushing an amorphous alloy having excellent magnetic properties. It increases the density of the composite magnetic material. According to such a method, a composite magnetic material having a high saturation magnetic flux density and a high magnetic permeability and a low loss can be manufactured. Further, it is possible to manufacture a composite magnetic material having excellent magnetic properties by a simple manufacturing method without requiring complicated processes and manufacturing equipment. Further, as the magnetic material, an inexpensive and highly available amorphous ribbon and its scraps can be used. Therefore, the manufacturing cost can be reduced.

Further, according to the method for producing a composite magnetic material according to the present embodiment, various molding dies can be applied depending on the application, so that the composite magnetic material can be easily formed into a required shape. Therefore, a thick composite magnetic material can be easily manufactured, and the degree of freedom in shape is high.

Further, the composite magnetic material manufactured by the method for manufacturing a composite magnetic material according to the present embodiment has high magnetic flux density, high magnetic permeability, and low loss, and can cope with a high frequency region. Therefore, it can be used as a magnetic core suitable for inductor elements such as reactors, choke coils, and transformers that require a large current.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

10 Flat metal powder 11 Binder 20 Molding mold 21 Opening 22 Lid material M, M1, M2, M3 Composite magnetic material

Claims (1)

A method for producing a composite magnetic material in which flat metal powder is oriented and dispersed in a binder.
The step of crushing the magnetic material to obtain the flat metal powder, and
The step of putting the flat metal powder into the molding mold and
A step of applying a vibrating force that vibrates in the horizontal direction orthogonal to the direction of gravity to the flat metal powder,
The step of impregnating the binder between the flat metal powders,
A method for producing a composite magnetic material having.

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