JP6480138B2 - Soft magnetic fine wire, mesh sheet for alternating current, sintered sheet for alternating current, rubber sheet for alternating current, laminated sheet for alternating current - Google Patents

Description

The present invention is a soft magnetic thin wire, the parallel Beauty, AC mesh sheet, AC sintered sheet, rubber sheet and for relates laminated sheet AC AC, more particularly, excellent soft magnetic characteristics in the frequency band of 15~150kHz soft magnetic thin wire, the parallel beauty, the soft magnetic thin line AC mesh sheet using, AC sintered sheet, rubber sheet and a AC laminated sheet AC.

  With the ubiquitous, in the mobile phone, the market of contactless wireless charging (charging only for placement) is expanding. With non-contact wireless charging, by placing a device (for example, a mobile phone) with a built-in secondary coil on a charger in which a primary coil is embedded, the coils are electromagnetically coupled to each other, and a battery built in the device is It says how to charge. In addition, non-contact wireless charging is also used as charging of electric toothbrushes, charging of electric or hybrid vehicles, antenna core materials of smart keys of vehicles, and antenna core materials of radio-controlled watches.

  The battery cover built in the mobile phone is usually made of metal. On the other hand, there is a demand for downsizing of the mobile phone, and the internal space of the mobile phone is limited. When the secondary coil and the metal part are close to each other inside the mobile phone, the charging electromagnetic wave from the primary coil generates an eddy current in the metal part. The eddy current causes a decrease in charging efficiency due to the generation of magnetic flux in the opposite direction, and causes heat generation of the metal component.

In order to improve the charging efficiency of the mobile phone in contactless wireless charging, it is effective to insert a soft magnetic material between the secondary coil and the metal part. As the soft magnetic material, for example, a magnetic sheet made of a complex of soft magnetic powder and rubber, a ferrite sintered product, etc. are known.
However, in order to reduce the charging time, it is necessary to increase the current to improve the charging efficiency. For that purpose, it is effective to make the soft magnetic material thicker.
On the other hand, in the mobile phone, since the space into which the soft magnetic material can be inserted is narrow, the soft magnetic material can not be made extremely thick.

In order to solve this problem, various proposals have conventionally been made.
For example, Patent Document 1 contains, by mass%, Ni: 35 to 50%, Cr: 5 to 10%, and Mn: 0.1 to 15%, and the balance is a soft composed of Fe and unavoidable impurities. Magnetic materials are disclosed.
The document describes that by using such a chemical composition, permeability and volume resistivity are improved as compared with conventional soft magnetic materials.

In Patent Document 2, Al: 1 to 10 atomic percent, Ga: 0.5 to 4 atomic percent, P: 0 to 15 atomic percent, C: 2 to 7 atomic percent, B: 2 to 10 atomic percent, Fe: A Fe-based soft magnetic metallic glass alloy, which is the balance, is disclosed.
The document describes that such an Fe-based soft magnetic metallic glass alloy is suitably used for an electromagnetic shielding net.

Patent Document 3 discloses a steel for an electromagnetic shield made of a soft magnetic metallic glass alloy represented by a composition formula: (Fe _{1 -ab} Co _a Ni _b ) _{100 -xy} M _x B _y . However, 0 ≦ a ≦ 0.29, 0 ≦ b ≦ 0.43, 5 atomic% ≦ x ≦ 20 atomic%, 10 atomic% ≦ y ≦ 22 atomic%, and M is Zr, Nb, Ta, Hf, It is an element consisting of one or more of Mo.

  Furthermore, Patent Documents 4 and 5 disclose an electromagnetic shielding material comprising a woven structure using a 70 μm diameter soft magnetic metal fiber made of an Fe-6.5 wt% Si alloy and a 60 μm diameter copper wire. ing.

  When the magnetic sheet is made of fibers made of a soft magnetic material, the magnetic properties can be improved without increasing the thickness extremely. However, even in the case of using a conventional material, sufficient magnetic properties can not be obtained, and the charging power is limited to 2 (W). That is, with conventional materials, there was a limit to shortening the charging time in non-contact wireless charging. In addition to mobile phones, this kind of non-contact charging has the potential need to reduce the thickness of the soft magnetic material, as it reduces the weight of the device and increases the freedom of installation location. .

JP, 2010-070814, A Japanese Patent Application Laid-Open No. 11-071656 Japanese Patent Application Laid-Open No. 11-071657 Japanese Patent Application Laid-Open No. 05-195365 Unexamined-Japanese-Patent No. 05-267883

An object of the present invention is to provide is to provide a soft magnetic thin line having excellent magnetic properties at a particular frequency range.
Another problem to be solved by the present invention is to provide a mesh sheet for alternating current, a sintered sheet for alternating current, a rubber sheet for alternating current, and a laminated sheet for alternating current using such soft magnetic fine wires.

In order to solve the above-mentioned subject, the soft magnetic wire concerning the present invention makes it a summary to have the following composition.
(1) The soft magnetic thin wire has a wire diameter of 0.15 mm or less.
(2) In the measurement field of the cross section of the soft magnetic thin wire, the area ratio of crystal grains having a crystal grain size in the range of 1 μm to 100 μm is 50% or more.
(3) The soft magnetic thin wire is made of a soft magnetic material having a saturation magnetic flux density of 0.6 T or more and 2.6 T or less, and a complex relative magnetic permeability at 125 kHz of 100 or more.
(4) The soft magnetic wire is used for a magnetic sheet used under an alternating current of 15 to 150 kHz.
(5) The soft magnetic thin wire is made of PC permalloy, PB permalloy, permendur or electromagnetic stainless steel.
The term "soft magnetic wire" generally refers to a soft magnetic material characterized by its small magnetic coercivity and high magnetic permeability, which are often used for magnetic cores such as coils and transformers, magnetic yokes, magnetic shields, etc. The material is processed into a thin line.

The mesh sheet for alternating current according to the present invention is
The soft magnetic thin wire according to the present invention is obtained by weaving so as to have a porosity of 80% or less.
The sintered sheet for alternating current according to the present invention is
Cutting the soft magnetic wire according to the present invention into a length of 0.1 mm or more and 500 mm or less,
It consists of what is obtained by arrange | positioning the cut | disconnected said soft-magnetic thin wire | wire in a fixed direction or at random, and sintering it so that a porosity may be 80% or less.
The rubber sheet for alternating current according to the present invention is
Cutting the soft magnetic wire according to the present invention into a length of 0.1 mm or more and 500 mm or less,
They are obtained by arranging the cut soft magnetic thin wires in a fixed direction or at random and combining them with rubber so as to have a porosity of 70% or less.
The laminated sheet for alternating current according to the present invention is
The soft magnetic thin wire according to the present invention is obtained by arranging the soft magnetic thin wires in a predetermined direction so as to have a porosity of 50% or less and bonding the soft magnetic thin wires with a binder.

  (Delete)

By optimizing the wire diameter, area ratio, material composition (in other words, magnetic characteristics such as saturation magnetic flux density and relative permeability) of the soft magnetic fine wire, magnetic characteristics in a specific frequency range are improved. A mesh sheet, a sintered sheet, a rubber sheet or a laminated sheet manufactured using such soft magnetic fine wire exhibits high magnetic properties in a specific frequency range despite the small thickness. In addition, when such a sheet is applied to, for example, contactless wireless charging of a mobile phone, charging power can be improved and charging time can be shortened.
In addition, the invention of the manufacturing method can be achieved by inclusion adjustment at the ingot stage and condition control at the final heat treatment stage, and can be implemented with less problems such as exceptional equipment and worker burden.

It is a figure which shows the charge electric power of the mesh sheet (plain weave, 78% of space ratio) using various materials. It is a figure which shows the relationship between the wire diameter of the mesh sheet (plain weave, 78% of space ratio) using PB permalloy, and charging power. It is a figure which shows the relationship of the area ratio of the mesh sheet (plain weave, 78% of space ratio) and charging power which used PB permalloy. It is an example of the microscope picture of the cross section which shows the crystalline state of a soft-magnetic wire. It is a figure which shows the relationship between (micro | micron | mu) ', (micro | micron | mu) ", or (micro | micron | mu)' / (micro | micron | mu)" and charging power.

Hereinafter, an embodiment of the present invention will be described in detail.
[1. Soft magnetic wire]
The soft magnetic wire according to the present invention has the following configuration.
(1) The soft magnetic thin wire has a wire diameter of 0.15 mm or less.
(2) In the measurement field of the cross section of the soft magnetic thin wire, the area ratio of crystal grains having a crystal grain size in the range of 1 μm to 100 μm is 50% or more.
(3) The soft magnetic thin wire is made of a soft magnetic material having a saturation magnetic flux density of 0.6 T or more and 2.6 T or less, and a complex relative magnetic permeability at 125 kHz of 100 or more.
(4) The soft magnetic wire is used for a magnetic sheet used under an alternating current of 15 to 150 kHz.

[1.1. Wire diameter]
The wire diameter of the soft magnetic wire influences the magnetic characteristics. Generally, the larger the wire diameter, the easier the eddy current is generated. In addition, as the wire diameter becomes larger, the contact area between the thin wires becomes larger when the thin wires are formed into a sheet, and eddy current is more likely to occur. The tendency changes gradually at the boundary of the wire diameter of 0.15 mm, and for example, in the extremely thin wire region of 0.10 mm or less, the rate of increase on the magnetic characteristics is higher. In particular, when the aspect ratio represented by the ratio of length / diameter of the soft magnetic thin wire to be used is 100 to 50000, the effectiveness is remarkable and suitable.
Therefore, in order to obtain high charging efficiency, the wire diameter of the soft magnetic wire needs to be 0.15 mm or less. The wire diameter is more preferably 0.050 mm or less, still more preferably 0.030 mm or less.
On the other hand, when the wire diameter becomes extremely thin, crystal grains do not grow, and the complex relative permeability of the thin line becomes low. In addition, when the wire diameter becomes too thin, manufacturing becomes difficult, such as breakage due to inclusions. Therefore, the wire diameter of the soft magnetic wire is preferably 0.005 mm or more. The wire diameter is more preferably 0.020 mm or more.
Here, "wire diameter" refers to the equivalent diameter (equivalent wire diameter) calculated from the area of the cross section. In the present application, the soft magnetic wire basically targets a round wire having a circular cross section. However, not limited to this, it is also possible to use non-circular oval or square cross section. In the case of a non-circular cross section, an arithmetically calculated value is obtained, which is taken as an equivalent wire diameter.

[1.2. Grain size]
The grain size of the soft magnetic wire influences the magnetic characteristics in a specific frequency range. In general, as the grain size is smaller, the permeability in the low frequency range is lower.
On the contrary, as the crystal grain size is larger, the permeability in the high frequency region is lowered.

  In order to obtain high permeability under alternating current of 15 kHz or more, the crystal grain size is preferably 1 μm or more. The crystal grain size is more preferably 5 μm or more. However, increasing the crystal grain size to more than 100 μm results in a decrease in the material strength of the fine wire, so the crystal grain size should preferably be adjusted to a range of about 5 to 30 μm. As a reference, FIG. 4 shows an example of a photomicrograph in which the cross section of a soft magnetic thin wire (heat treatment temperature: 673 K · 1083 sec, 1173 K · 20 sec, 1373 K · 2 sec) having a wire diameter of 0.050 mm. As seen from this, the crystal structure changes depending on the heat treatment conditions, and although it is relatively stable particularly in the temperature range of 673 to 1373 K, it can be seen that crystals of various sizes are mixed. In addition, a crystal grain diameter shall be shown by the average value of the major axis and the minor axis of the crystal grain.

[1.3. Area ratio]
In order to use the soft magnetic thin wire as a magnetic sheet in a specific frequency range, the larger the number of crystal grains in which the crystal grain size is in a predetermined range, the better. In order to obtain high magnetic properties in the frequency range of 15 kHz to 150 kHz, the area ratio of crystal grains having a crystal grain size in the range of 1 μm to 100 μm needs to be 50% or more, and a more preferable form is a crystal grain The area ratio of crystal grains having a diameter in the range of 5 μm to 30 μm is 80% or more. Also in this case, the remaining 20% or less is preferably a crystal grain (that is, less than 5 μm) smaller than the set range. In the present invention, in order to simplify verification of the area ratio, the top five coarse crystal grains in the measurement field of view are extracted, and the average value of the five coarse crystal grains is the crystal grain size. It is also preferable to be in the range of

Here, the “area ratio” refers to a value represented by the following equation (1).
Area ratio (%) = ΣS _i × 100 / S ₀ (1)
However,
S ₀ is the area of a predetermined measurement visual field (for example, the measurement magnification is 400 to 1,500 times according to the size of a predetermined crystal grain),
SS _i is the sum of the cross-sectional areas (S _i ) of the individual crystal grains in which the crystal grain size is in a predetermined range (in the range of 1 μm to 100 μm).

[1.4. Saturated magnetic flux density]
The saturation magnetic flux density of the soft magnetic material constituting the soft magnetic wire influences the charging power. The saturation magnetic flux density is a value inherent to the material. In general, as the saturation magnetic flux density increases, the charging power can be increased. In order to obtain a magnetic sheet capable of obtaining a charge power of 2 (W) or more, the saturation magnetic flux density of the soft magnetic material needs to be 0.6 T or more. The saturation magnetic flux density is more preferably 0.8 T or more, still more preferably 1.0 T or more. However, if it exceeds 2.6 T, the charge power is saturated, so that 0.6 T or more and 2.6 T or less is preferable.

[1.5. Complex relative permeability]
The complex relative permeability of the soft magnetic material constituting the soft magnetic wire affects the charging power. The measurement can be obtained from the following equation based on, for example, the real part (μ ′) and the imaginary part (μ ′ ′) measured by LCR.
Complex relative magnetic permeability μ = μ′−jμ ′ ′ where j is an imaginary number.
The complex relative magnetic permeability depends not only on the material composition but also on the structure of the material (wire diameter, crystal grain size, processing strain, etc.) and the use condition (frequency). In general, the charge power can be increased as the complex relative permeability increases. The real part μ ′ of the 125 kHz complex relative permeability is a typical value, and exhibits substantially the same value at 15 to 150 kHz. For example, in the case of charging of a mobile phone, the complex relative permeability of the soft magnetic material at 125 kHz is 100 or more in order to obtain a magnetic sheet capable of obtaining charging power of 2 (W) or more in the frequency range of 125 kHz. It needs to be. The complex relative permeability at 125 kHz is more preferably 150 or more. Also, in the vicinity of 20 kHz in the case of wireless charging of a car, it exhibits the same value as the permeability of 125 kHz.
On the other hand, when the complex relative permeability is too high, for example, when the saturation magnetic flux density B = 1.0 T [10000 G] and the complex relative magnetic permeability μ1000010000, the saturation occurs in the low magnetic field H = 1.0 [Oe]. Therefore, the complex relative magnetic permeability μ becomes 1 in a high magnetic field such as power 2 [W]. Therefore, the complex relative permeability at 125 kHz is preferably 1000 or less. The complex relative permeability is more preferably 500 or less.
Further, in relation to the complex relative permeability, the soft magnetic thin wire has a ratio μ '/ μ "with an imaginary part permeability μ" having a real part permeability μ' of 200 or more and 350 or less as measured by LCR meter. It is also preferable that is 10 or more and 100 or less.
These values can similarly be arbitrarily adjusted according to, for example, the production conditions of the fine wire, particularly the heat treatment conditions and the crystal grain size accordingly.

[1.6. Specific Example of Soft Magnetic Material]
Examples of soft magnetic materials that satisfy the conditions described above include the following.
(1) There is a Fe-Ni-Mo-Cu alloy (PC permalloy; described in JIS-C2531) containing 70 to 80% by mass of Ni, and as a more preferable example, C ≦ 0.02% by mass, Si ≦ 0.60 mass %, Mn ≦ 0.80 mass%, Ni: 75 to 82 mass%, and further containing 0 to 6 mass% of Mo and / or Cu, respectively.
(2) A Fe-0 to 1% by mass Mn alloy containing 40 to 50% by mass of Ni corresponding to PB permalloy. As a more preferable example, C ≦ 0.02 mass%, Si ≦ 0.60 mass%, Mn ≦ 0.50 mass%, Ni: 40 to 50 mass%, and the above Mo and Cu are each 0 to 6 mass. % Can also be included.
(3) A permendur alloy containing Fe and Co at a mass ratio of about 1: 1 (e.g., 0.95 to 1.05: 1.05 to 0.95) and further containing 1 to 3% by mass of V.
(4) Electromagnetic pure iron.
(5) Fe-Si alloy (silicon iron) containing 0.4 to 5% by mass of Si, Fe-7 to 18% by mass Cr, Fe-7 to 18% by mass Cr-0.1 to 3% by mass Si -0.1 to 3% by mass Al, Fe-0.1 to 3% by mass Al-0.1 to 3% by mass Si.
(6) Fe-Cr based electromagnetic stainless steel containing 7 to 15% of Cr.
Among these alloys, in particular, PC permalloy and PB permalloy are excellent in workability and suitable for ultra-fine reduction, and permendur, electromagnetic pure iron, silicon iron and electromagnetic stainless steel are most suitable for the production method. As a result, high charging power can be obtained, which is suitable as a material for forming the soft magnetic wire.

[1.7. Insulating layer]
An insulating layer may be formed on the surface of the soft magnetic wire. When the insulating layer is present on the surface of the soft magnetic thin wire, the flow of current between the thin wires is shut off, thereby further suppressing the generation of the eddy current. Also, this can further improve the charging efficiency.
In particular, when the wire diameter of the thin wire is relatively thick and / or the contact pressure between the thin wires is relatively large when formed into a sheet, the contact area between the thin wires becomes large. In such a case, when the insulating layer is formed on the surface of the thin wire, generation of eddy current can be suppressed.

  As a material of an insulating layer, thermoplastic resin materials, such as a polytetrafluoroethylene, a silicone resin, a polyurethane, a polyimide, are preferable, for example. The soft magnetic wire is surface-coated with any one or more of them. In the molding process, for example, the coating can be made uniform by passing through the molten resin layer at a constant speed by a strand system at the final finishing stage of the fine wire. The layer thickness is usually 1 to 100 μm depending on the material of the insulating agent. The soft magnetic fine wire in which the insulating layer is formed can be used for the mesh sheet for alternating current, the rubber sheet for alternating current, the lamination sheet for alternating current, etc. which are mentioned later.

[2. Mesh sheet for exchange]
The mesh sheet for alternating current according to the present invention is obtained by weaving using the soft magnetic thin wire according to the present invention so as to have a porosity of 80% or less. If necessary, it can be further compressed into a flat mesh, or, for example, a plurality of mesh sheets can be laminated in multiple layers or compressed. In the case of such compression processing, in order to recover the magnetic properties which are deteriorated with the processing, it is desirable to apply heat treatment at the end to adjust the crystal grain size to be in the above range.
Such multi-layering can reduce the aperture and provide higher magnetic properties than with a single layer mesh.

[2.1. Space rate]
In addition, the "porosity" in a mesh sheet means the ratio of the space per predetermined plane when seeing through the mesh sheet in the thickness direction. In general, the lower the porosity of the mesh sheet, the greater the amount of magnetic flux absorption. As the amount of magnetic flux absorption increases, charging power is improved. In order to obtain high charging power, the space factor needs to be 80% or less. The porosity is more preferably 50% or less, still more preferably 30% or less.
On the other hand, when the porosity becomes too small, the contact pressure between the thin lines becomes high, and the conduction resistance between the thin lines decreases. As a result, an eddy current is generated and the charging power is greatly reduced. Therefore, the porosity is preferably 10% or more. The porosity is more preferably 20% or more.

[2.2. Weaving method]
The weave of the soft magnetic fine wire is not particularly limited, and various weaves can be used. The weaving method is, for example, plain weave, twill weave, plain tatami weave, crimped net, welded wire mesh, turtleskin woven wire, etc.
The soft magnetic thin wire used for the mesh sheet may use not only a round wire having a circular cross-sectional shape but also an irregular wire having a non-circular cross-sectional shape, and in such a case, the wire diameter display may be the area of the cross section The equivalent diameter (equivalent wire diameter) calculated from

[3. AC sintered sheet]
The sintered sheet for alternating current according to the present invention is
Cutting the soft magnetic wire according to the present invention into a predetermined length, for example, 0.1 mm or more and 500 mm or less,
The soft magnetic thin wires which are cut are arranged in a predetermined direction or in a random manner, and sintered so as to have a porosity of 80% or less, as in the case of the mesh sheet, At the same time, it is preferable to reduce the space of the thin wire by compression molding to a predetermined thickness.
The sheet is pressure sintered to, for example, about 0.3 to 5 mm. The sheet is formed to have a thickness of about 0.3 to 5 mm. In the forming process, for example, the fine wires are directly sintered together, or the fine wires are previously provided with an insulating layer described later on the surface of the fine wires, and the insulating layers are integrated by fusion. It is also good. The space factor can be appropriately adjusted in accordance with the degree of pressurization, and at the same time, the thin lines are mutually diffused and coupled at the contact portions with the adjacent thin lines. As a result, a sheet molding which is easy to handle as a whole is obtained. Further, as in the present embodiment, in the case of integrating by sintering, the soft magnetic thin wires are substantially uncoated and their distribution state also aligns each thin wire in a certain direction in multiple layers as described above. In addition to the arranged ones, they may be arranged in a cotton-like random direction and entangled.

[3.1. Soft Magnetic Wire Length]
The length of the soft magnetic fine wire for producing a sintered sheet for alternating current also affects the magnetic characteristics of the molded product, and from the viewpoint of maintaining a predetermined molded product shape, the use of a long thin wire is recommended . If the length of the soft magnetic thin wire is too short, sufficient entanglement between thin wires can not be obtained, and sufficient handling strength can not be obtained as a thin sheet molded product. Therefore, the length of the soft magnetic wire needs to be 0.1 mm or more. The length of the soft magnetic thin wire is more preferably 1 mm or more so that the aspect ratio is 100 times or more.
On the other hand, when the thin wires are arranged in random directions as in the latter case, if the length of the soft magnetic thin wire is too long, the thickness of the sheet after sintering and the dispersion of the distribution become large. Therefore, the length of the soft magnetic wire needs to be 500 mm or less. The length of the soft magnetic wire is more preferably 100 mm or less.

[3.2. Space rate]
The "porosity" refers to the ratio of space to the apparent volume of the sintered sheet. In general, the lower the porosity of the sintered sheet, the greater the amount of absorbed magnetic flux. As the amount of magnetic flux absorption increases, charging power is improved. In order to obtain high charging power, the space factor needs to be 80% or less. The porosity is more preferably 60% or less, still more preferably 50% or less.
On the other hand, when the porosity becomes too small, the contact pressure between the thin lines becomes high, and the conduction resistance between the thin lines decreases. As a result, an eddy current is generated and the charging power is greatly reduced. Therefore, the porosity is preferably 5% or more. The porosity is more preferably 10% or more.
The space ratio is desired to be uniform throughout the sheet, but complete homogenization is technically difficult and it is inevitable that partial variations occur. On the premise of that, in the present invention, the measurement of the porosity is indicated by a randomly selected unit area of the sheet, for example, a porosity per 10 cm ² (average porosity).

[4. AC rubber sheet]
The rubber sheet for alternating current according to the present invention is
Rubber material as a matrix, inside it,
Cutting the soft magnetic wire according to the present invention into a length of 0.1 mm or more and 500 mm or less,
They are obtained by arranging the cut soft magnetic thin wires in a fixed direction or at random and combining them with rubber so as to have a porosity of 70% or less.
The molding thickness is, for example, integrally combined in a sheet shape of about 0.05 to 0.5 mm, and for example, a predetermined amount of the thin wire is kneaded in a molten rubber material, and extruded or coated. It is molded by impregnating a rubber material of a matrix in a gap formed in a predetermined thickness or in which the long thin wires are aligned in a predetermined direction. By making the arrangement in a close contact state, the space factor can be further reduced.

[4.1. Soft Magnetic Wire Length]
With regard to the length of the soft magnetic wire, in the case where the soft magnetic wire is composited in a predetermined matrix, in the former random arrangement, dispersion by kneading is difficult to perform for long wires longer than necessary, and the latter is a certain direction In the arrangement, since a long thin wire having a length of at least 10 mm or more is preferable, for example, it is desirable to use a powdery or strip-like thin wire of 100 mm or less.
[4.2. Space rate]
The “porosity” refers to the ratio of the apparent volume occupied by the portion (space portion) excluding the thin wire present inside the fixed volume of the rubber sheet, except that the upper limit is 70%. Since it is the same as that of the sintered sheet for alternating current, the description is omitted.
[4.3. Rubber]
The material of the rubber used for the alternating current rubber sheet is not particularly limited, and an optimum material can be selected according to the purpose.

[5. Laminated sheet for alternating current]
The laminated sheet for alternating current according to the present invention is
A plurality of the soft magnetic thin wires (for example, 30 to 10,000 per sheet width 10 mm) according to the present invention are aligned in substantially constant directions in multiple layers, and a thin film so that the porosity is 50% or less It forms a sheet. Further, between the thin wires, for example, resin sheet materials used for the front and back surfaces thereof are impregnated in the gaps between the thin wires by pressure fusion and are distributed in a separated state. The formed thickness of the sheet is, for example, a film of about 1 mm or less, and such a composite technology is called a prepreg method in the technical field of fiber reinforcement.

[5.1. Arrangement of soft magnetic wires]
In the alternating current laminated sheet, the soft magnetic thin wires are arranged in a predetermined direction. As a method of arranging soft magnetic thin wires in one direction, there is a method of winding thin wires in a predetermined drum in an aligned state, for example, a method of closely laminating multiple layers and cutting after film formation.
[5.2. Space rate]
As in the case of the rubber sheet for alternating current, the “porosity” means the ratio of the volume equivalent to the space occupied by the resin matrix excluding the soft magnetic thin line per fixed volume of the laminated sheet.
[5.3. resin]
The material of the resin used for the alternating current laminated sheet is not particularly limited, and an optimum material can be selected according to the purpose. For example, the same thermoplastic resin material as that used for the insulating layer is used be able to.
Moreover, in these mesh sheets, sintered sheets, rubber sheets, and laminated sheets, two or more types of different kinds of wire diameters and types, for example, can be used in combination as appropriate as the soft magnetic thin wires.

[6. Method of manufacturing soft magnetic wire]
The method of manufacturing a soft magnetic thin wire according to the present invention includes a melting step, a wire manufacturing step, and a heat treatment step. The method of manufacturing the soft magnetic wire may further include an insulating layer forming step.

[6.1. Dissolution process]
First, the soft magnetic material having a saturation magnetic flux density of 0.6 T or more and 2.6 T or less is melted (melting step). The melting and casting method is not particularly limited, and an optimum method can be selected according to the purpose.

The obtained ingot may be subjected to the next step as it is, or electroslag remelting may be performed once or more (remelting step).
There are usually relatively large non-metallic inclusions in the material obtained by the simple melting and casting method. If the material is subjected to wire drawing in this state, many breakages occur during wire drawing, and the yield significantly deteriorates.

Therefore, in the present invention, it is intended to provide an extremely thin area having a wire diameter of 0.15 mm or less, and to provide sufficient strength characteristics suitable for drawing to that area and use as a formed sheet. It is effective to reduce and clean nonmetallic inclusions by the electroslag remelting. The process may perform at least one electroslag remelting on the material prior to wiredrawing. Thereby, coarse nonmetallic inclusions can be removed. Moreover, the disconnection at the time of wire-drawing processing is suppressed, and a yield improves.
In order to reduce non-metallic inclusions, the number of times of electroslag remelting is better the better. Re-dissolution conditions are not particularly limited, and optimum conditions can be selected according to the material composition.

[6.2. Wire rod manufacturing process]
Next, the ingot obtained in the melting step is rolled and / or drawn (wire rod manufacturing step).
The method and conditions of rolling and wire drawing are not particularly limited, and optimum conditions can be selected according to the material composition. In particular, in the wire drawing in the thin wire region, it is preferable to make the crystal grains into fine fibers of, for example, 1000 nm or less by a high drawing process with a final processing rate of 80 to 98%. Wet wire drawing by is recommended.

6.3. Heat treatment process]
Next, the wire obtained in the wire manufacturing step is heat-treated to obtain the soft magnetic thin wire according to the present invention (heat treatment step).
Heat treatment is performed to remove the processing strain introduced into the material during rolling and drawing. The heat treatment conditions are important because they affect the alternating current magnetic characteristics of the thin wire, and heating of 673 to 1373 K is performed.
If the heat treatment temperature is higher than 1373 K, the strength characteristics are degraded as the crystal grains are coarsened, and predetermined properties and sheet forming processing are difficult to obtain, and conversely, if the heating temperature is less than 673 K, the heat treatment temperature is less than 673 K A predetermined crystal structure in the thin line can not be obtained, and a predetermined magnetic characteristic can not be obtained.
In such a temperature range, it is effective to set the heat treatment time to a range determined by the following equation (2) as a measure to obtain a soft magnetic thin wire having more preferable magnetic characteristics and mechanical characteristics.
(1 × 10 ⁷ ) / 3 exp (0.012 T) ≦ t ≦ (1 × 10 ⁹ ) / 3 exp (0.012 T) (2)
However,
T is a heat treatment temperature (K), t is a heat treatment time (sec), 673 ≦ T ≦ 1373.
If the heat treatment time is too long, the crystal grains become coarse and the complex relative permeability at 125 kHz decreases.
On the other hand, when the heat treatment time is too short, a large amount of processing distortion remains, and the complex relative permeability decreases.

In order to obtain high charging power, it is preferable that the heat treatment conditions satisfy the above equation (2). When heat treatment is performed on the wire after wire drawing so as to satisfy formula (2), a soft magnetic wire having a predetermined complex relative permeability is obtained. Equation (2) holds regardless of the material.
The heat treatment conditions are particularly preferably those satisfying the formula (2.1).
(1 × 10 ⁷ ) / 3 exp (0.012 T) ≦ t ≦ (1 × 10 ⁸ ) / 3 exp (0.012 T) (2.1)
The heat treatment may be an "in-line method" performed continuously while performing wire drawing processing, or may be an "off-line method" performed on a wire rod for which wire drawing processing has been completed. More preferably, the dew point temperature is- It is desirable to carry out rapid cooling at a cooling rate of 100 K / sec or less with hydrogen gas at 50 ° C. or less.

[6.4. Insulating layer formation process]
Next, as needed, an insulating layer is formed on the surface of the heat-treated soft magnetic fine wire (insulating layer forming step). Although the insulating layer forming step is not necessarily required, when the insulating layer is formed on the surface of the soft magnetic wire, the flow of current between the wires is interrupted. In addition, the corrosion resistance is also improved. Therefore, the charge efficiency of the magnetic shield sheet is further improved.

The method for forming the insulating layer is not particularly limited, and various methods can be used depending on the purpose.
As a method of forming the insulating layer, for example, the thin wire is allowed to pass through the inside of a storage tank in which a predetermined insulating agent is adjusted to be in a molten state of a constant viscosity by surface coating treatment to obtain a set thickness. Can be surface coated.

[7. Action]
By optimizing the wire diameter, area ratio, material composition (in other words, magnetic characteristics such as saturation magnetic flux density and complex relative permeability) of the soft magnetic thin wire, magnetic characteristics in a specific frequency range are improved. A mesh sheet, a sintered sheet, a rubber sheet or a laminated sheet manufactured using such soft magnetic fine wire exhibits high magnetic properties in a specific frequency range despite the small thickness. In addition, when such a sheet is applied to, for example, contactless wireless charging of a mobile phone, charging power can be improved and charging time can be shortened.

(Examples 1 to 3, Reference Examples 4 to 5, Example 6, Comparative Examples 1 to 2)
[1. Preparation of sample]
Electroslag remelting, wire drawing and heat treatment were performed on various materials. Materials include permendur (Example 1), PB permalloy (Example 2), PC permalloy (Example 3), 1% silicon iron (Reference Example 4) , electromagnetic pure iron (Reference Example 5) , electromagnetic stainless steel Steel (Example 6), carbon steel (Comparative Example 1), and SUS 304 (Comparative Example 2) were used. Moreover, the wire diameter was 0.015 mm. Furthermore, it was heat-treated so that the crystal grain size and area ratio become almost the same. For example, the heat-treatment conditions for the permalloy materials of Examples 2 and 3 were adjusted within the range of temperature 973 K to 1273 K × 10 to 40 sec. It was done. The “minimum (maximum) particle size” is the particle size of the smallest (maximum) crystal grain in the field of view.
The obtained thin wire was plain-woven so as to have a space ratio of 78% to obtain a mesh sheet.

[2. Test method]
[2.1. Complex relative permeability]
The sample (thin wire) was placed in a magnetic ring case for measurement, the measurement coil was wound 50 turns, and the complex relative permeability at 125 kHz was measured using an LCR meter method with E-4980A manufactured by Agilent Technologies.
[2.2. Saturated magnetic flux density]
Place the sample in the magnetic ring case for measurement, wind the coil for measurement (primary side: 50 turns, secondary side: 20 turns), and use the DC B-H method with BH5501 manufactured by Electro Magnetic Industries, using the saturation magnetic flux The density was measured.
[2.3. Charge power]
The charge power was measured by laying 20 turns on the primary side coil (outside diameter: 30 mm, inner diameter 20 mm) and the secondary side coil in the same manner. The measurement frequency was 125 kHz or 20 kHz.

[3. result]
Table 1 shows the results. In Table 1, the material composition is also shown. Further, FIG. 1 shows the charging power of mesh sheets (plain weave, 78% in space ratio) using various materials. The following can be understood from Table 1 and FIG.

(1) Carbon steel has a low complex relative permeability. In addition, SUS304 has low complex relative permeability and saturation magnetic flux density. Therefore, the charging power of the mesh sheet using them was all significantly lower than 2 (W).
(2) Permendur, PB permalloy, PC permalloy, 1% silicon iron, electromagnetic pure iron, and electromagnetic stainless steel all have high complex relative magnetic permeability and saturation magnetic flux density. Therefore, the charging power of the mesh sheet using these was all 2 (W) or more.

(Examples 11 to 13 and Comparative Examples 11 to 12)
[1. Preparation of sample]
Electroslag remelting, wire drawing and heat treatment were performed on PB permalloy. The wire diameter and the crystal grain size were changed by changing the drawing conditions and the heat treatment conditions.
The obtained thin wire was plain-woven so as to have a space ratio of 78% to obtain a mesh sheet.
[2. Test method]
The complex relative magnetic permeability, the saturation magnetic flux density, and the charging power were evaluated in the same manner as in Example 1. The measurement frequency of charging power was 125 kHz.

[3. result]
Table 2 shows the results. Table 2 also shows the material composition. Further, FIG. 2 shows the relationship between the wire diameter of the mesh sheet (plain weave, void ratio 78%) using PB permalloy and the charging power. It can be seen from Table 2 and FIG. 2 that when the wire diameter is 0.15 mm or less, the charging power is significantly improved.

(Example 21, Comparative Examples 21 to 23)
[1. Preparation of sample]
Electroslag remelting, wire drawing and heat treatment were performed on PB permalloy. The crystal grain size and the area ratio were changed by changing the heat treatment conditions.
The obtained thin wire was plain-woven so as to have a space ratio of 78% to obtain a mesh sheet.
[2. Test method]
The complex relative magnetic permeability, the saturation magnetic flux density, and the charging power were evaluated in the same manner as in Example 1. The measurement frequency of charging power was 125 kHz.

[3. result]
Table 3 shows the results. Table 3 also shows the material composition. Further, FIG. 3 shows the relationship between the area ratio of the mesh sheet (plain weave, space ratio 78%) using PB permalloy and the charging power. It can be seen from Table 3 and FIG. 3 that when the area ratio is 50% or more, the charging power is significantly improved.

(Examples 31 to 37, Comparative Examples 31 to 34)
[1. Preparation of sample]
Electroslag remelting, wire drawing and heat treatment were performed on PB permalloy. Note that electroslag remelting was not performed for some of the materials. Moreover, the wire diameter, the crystal grain size, and the area ratio were changed by changing the manufacturing conditions.
Next, the obtained thin line was cut into a predetermined length. The cut thin line was sintered so as to have a predetermined porosity to obtain a sintered sheet. Further, the cut thin line was mixed with rubber so as to have a predetermined porosity, to obtain a rubber sheet. Further, the cut thin line was mixed with a resin so as to obtain a predetermined space ratio, and a laminated sheet was obtained by a prepreg method.

[2. Test method]
[2.1. Complex relative permeability, saturation flux density, charge power]
The complex relative magnetic permeability, the saturation magnetic flux density, and the charging power were evaluated in the same manner as in Example 1. The measurement frequency of charging power was 125 kHz.
[2.2. Tensile test]
The thin wire was subjected to a tensile test to measure elongation. The tensile test conditions made the test piece No. 4 standard according to JIS Z 2201.
[2.3. Product yield]
The product sheet weight was divided by the input cut thin line weight and multiplied by 100 to determine the product yield.

[3. result]
Table 4 shows the results. Also, FIG. 5 shows the relationship between μ ′, μ ′ ′, or μ ′ / μ ′ ′ and the charging power. The following can be understood from Table 4 and FIG.
(1) In Comparative Example 31, since the wire diameter exceeds 0.15 mm, the complex relative magnetic permeability and the charging power are low.
(2) In Comparative Examples 32 and 33, since the area ratio is less than 50%, the complex relative magnetic permeability and the charging power are low.
(3) Comparative Example 34 has low complex relative magnetic permeability and charging power because the elongation is low.
(4) In all of Examples 31 to 37, the charging power was 2 (W) or more. However, Example 36 has low product yield because electroslag remelting is not performed.

(Examples 41-45, Comparative Examples 41-45)
[1. Preparation of sample]
Electroslag remelting, wire drawing and heat treatment were performed on PB permalloy. Note that electroslag remelting was not performed for some of the materials. Moreover, the wire diameter, the crystal grain size, and the area ratio were changed by changing the manufacturing conditions.
The obtained thin line was plain-woven so as to have a predetermined space ratio to obtain a mesh sheet.
[2. Test method]
In the same manner as in Example 31, the complex relative magnetic permeability, the saturation magnetic flux density, the charge power, the tensile properties, and the product yield were evaluated. The measurement frequency of charging power was 125 kHz.

[3. result]
Table 5 shows the results. From Table 5, the following can be seen.
(1) In Comparative Example 41, since the wire diameter exceeds 0.15 mm, the complex relative magnetic permeability and the charging power are low.
(2) In Comparative Example 42, since the mesh space ratio exceeds 80%, the charging power is low.
(3) In Comparative Examples 43 and 44, since the area ratio is less than 50%, the complex relative magnetic permeability and the charging power are low.
(4) Comparative Example 45 has low elongation, and also has low complex relative magnetic permeability and charge power.
(5) In all of Examples 41 to 45, the charging power was 1.7 (W) or more. However, in Example 45, the product yield is low because electroslag remelting is not performed.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited at all to the said embodiment, A various change is possible within the range which does not deviate from the summary of this invention.

The soft magnetic wire and the method of manufacturing the same according to the present invention can be used as a material of a magnetic sheet for non-contact wireless charging and a method of manufacturing the same.
Further, the mesh sheet for alternating current, the sintered sheet for alternating current, the rubber sheet for alternating current, and the laminated sheet for alternating current according to the present invention are non-contacts of the magnetic sheet of the mobile phone, the electric car (EV) and the hybrid car (HEV, PHEV) It can be used as a soft magnetic core material for wireless charging, a smart keyless antenna core of a car, and an antenna core of a radio-controlled watch.

Claims (7)

Soft magnetic wire with the following configuration.
(1) The soft magnetic thin wire has a wire diameter of 0.15 mm or less.
(2) In the measurement field of the cross section of the soft magnetic thin wire, the area ratio of crystal grains having a crystal grain size in the range of 1 μm to 100 μm is 50% or more.
(3) The soft magnetic thin wire is made of a soft magnetic material having a saturation magnetic flux density of 0.6 T or more and 2.6 T or less, and a complex relative magnetic permeability at 125 kHz of 100 or more.
(4) The soft magnetic wire is used for a magnetic sheet used under an alternating current of 15 to 150 kHz.
(5) The soft magnetic thin wire is made of PC permalloy, PB permalloy, permendur or electromagnetic stainless steel.   The soft magnetic thin wire has a real part permeability μ ′ of 200 to 350 and a ratio μ ′ / μ ′ ′ to the imaginary part permeability μ ′ ′ of 10 to 100 according to LCR measurement. Soft magnetic wire.   The soft magnetic fine wire according to claim 1 or 2, wherein the surface is covered with an insulating layer made of polytetrafluoroethylene, silicone resin, polyurethane or polyimide. A soft magnetic thin wire according to any one of claims 1 to 3, exchange diverted mesh sheet is 80% or less spatial rate. A soft magnetic thin wire according to claim 1 or 2, the soft magnetic thin line under 500mm following more length 0.1mm is placed in a constant direction or randomly, is 80% or less between rate Check exchange diversion sintered sheet. It consists claim soft magnetic thin wire according to any one of from 1 to 3, 0.1 mm or more length 500mm less of the soft magnetic thin line is placed in a constant direction or randomly spatial rate 70 % is hereinafter, rubber complexed with the intersection diverted rubber sheet. Side by side in a predetermined direction from claim 1 to the soft magnetic thin line becomes 50% or less space factor according to any one of up to 3, exchange diverted laminated sheets joined by a binder between the soft magnetic thin line.

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