JP2918254B2 - Manufacturing method of magnetic core - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a magnetic core used for an iron core for a transformer or an iron core for a motor.

[Conventional technology]

Japanese Patent Publication No. Sho 62-37114 discloses an example of this type of technology.

In the publication, an amorphous magnetic steel strip (magnetic ribbon)
Describes a technique in which a surface treatment such as a phosphate treatment and / or a chromate treatment is performed on the resultant, an insulating film is attached, and then annealing is performed in an oxidizing atmosphere.

That is, in a magnetic ribbon which has been subjected to an insulating film treatment of this kind in advance, the iron loss characteristics are improved by performing annealing in an oxidizing atmosphere, and the characteristics are higher than those in the case of annealing in a nitrogen atmosphere. It has been found that they show equal or better performance.

[Problems to be solved by the invention]

However, in the above-mentioned technique, it cannot be said that sufficient consideration is given to deterioration of magnetic permeability due to annealing.

That is, when an amorphous magnetic ribbon is manufactured as a magnetic ribbon, annealing is performed at about 400 ° C. When such annealing is performed, the difference in linear expansion coefficient between the insulating film and the ribbon, that is, almost all In this case, since the linear expansion coefficient of the insulating film is larger than that of the amorphous ribbon, a compressive stress is generated in the ribbon, and the magnetic permeability is deteriorated due to the adverse effect of magnetostriction.

In addition, there is a problem that the insulating film that can withstand annealing at about 400 ° C. is limited in material, and furthermore, when an insulating film is provided, a magnetic core is formed.
And the size of the magnetic core increases as a result.

The present invention has been made under such a background, and it has been found that the lowering of the space factor is minimized, the insulation between the ribbon layers is ensured, and both the improvement of the iron loss characteristics and the improvement of the magnetic permeability are satisfied. It is an object of the present invention to provide a technology for manufacturing a magnetic core.

[Means for solving the problem]

The present invention has been made focusing on the following points as its theoretical premise.

That is, for the interlayer insulating film in the magnetic ribbon, how to find an insulating film material having good insulating performance is the greatest concern among those skilled in the art.

However, from a viewpoint, it is considered that even if there is no insulating film, if there is an air layer between the layers, the air layer becomes an insulating layer, which can prevent eddy current and increase the space factor.

Therefore, in the present invention, in order to secure such an air layer, fine particles of a non-magnetic material made of an oxidizing inorganic substance having an insulating property are used between the magnetic ribbon laminates, and these fine powders serve as spacers in the air layer. Was annealed in a state of being interposed to form.

At the same time, the present invention is characterized in that an oxidizing inorganic substance is used as such fine powder.

In addition, in the case of a magnetic ribbon alone, the fine powder must adhere to the ribbon surface, but when the magnetic ribbon is wound or laminated, the fine powder does not need to adhere,
It suffices to be interposed between the ribbons.

[Action]

Hereinafter, the operation of the present invention will be described, and more specifically, the solving means will be described.

In the present invention, a fine powder made of an oxidizing inorganic substance is adhered to at least one surface to form a magnetic ribbon. Therefore, when this magnetic ribbon is wound or laminated to form a magnetic core, the fine powder becomes a spacer, and An air layer is formed between each layer.

Here, the magnetic ribbon in the present invention is a thin ribbon of a magnetic material, and the magnetic material is Fe, Co, Ni in a transition metal.
Ferromagnetic elements alone, or alloys of ferromagnetic elements,
Examples thereof include alloys of non-ferromagnetic elements and ferromagnetic elements, ferrite, permalloy, amorphous alloys, and the like, which are added to improve characteristics. As an amorphous metal, Fe-B,
Fe-BC, Fe-B-Si, Fe-B-Si-C, Fe-B-Si-Cr,
Fe-based materials such as Fe-Co-B-Si, Fe-Ni-Mo-B, Co-B, Co-F
e-Si-B, Co-Fe-Ni-Mo-B-Si, Co-Fe-Ni-BS
i, Co-Fe-Mn-B-Si, Co-Fe-Mn-Ni, Co-Mn-Ni-B
-Co, Co-Fe-Mn-Ni-B and the like.

Further, in the present invention, an Fe-based microcrystalline soft magnetic material such as an Fe-Si-B-Cu-Nb-based alloy can be used as the magnetic material in addition to the amorphous metal.

In addition, as the magnetic material used in the present invention, in addition to the above, a magnetic material which is initially in an amorphous state, but has a structure of fine crystal grains when subjected to heat treatment, for example, Fe-Cu-Nb
-Si-B-based alloy, as a specific composition, Fe _73.5 -Cu ₁
It can be exemplified -Nb ₃ -Si _13.5 -B _9.

In the present invention, an air layer is formed by interposing fine particles of a non-magnetic substance made of an oxidizing inorganic substance having an insulating property as spacers between the laminated bodies of such magnetic ribbons.

The fine powder used in the present invention is an oxidizing inorganic substance.
This is because the surface of the magnetic ribbon is oxidized and covered with an insulating oxide film. Suitable examples of such an oxidizing inorganic substance include diantimony pentoxide or antimony trioxide, which may be present at the same time.

The condition is that the fine powder of the oxidizing inorganic substance is a non-magnetic substance and has insulating properties. This is because when the fine powder is a magnetic substance or a conductor, the magnetic permeability is degraded or the eddy current is increased.

Looking at the particle size of the fine powder of these oxidizing inorganic substances,
Considering that the fine powder is evenly attached to and interposed on the ribbon to form an insulating layer, the particle size of the fine powder may be small,
Extremely small size is a factor that makes manufacturing difficult.
On the other hand, if it is too large, when the magnetic core is formed by the ribbon, the width of the gap between the ribbons becomes too large, and the space factor of the magnetic material becomes small. For these reasons, the particle size of the fine powder is 10 nm to 2 nm.
μm is desirable.

In addition, the amount of fine powder adhering and interposing
The amount of fine powder per m ² ) is preferably 10 ⁻⁷ cm ³ to 2 × 10 ⁻⁴ cm ³ , more preferably 3 × 10 ⁻⁶ cm ³ to 10 ⁻⁵ cm ^3. . When this amount of adhesion / intervention is converted into the weight of the fine powder per unit area, the value changes depending on the specific gravity of the material of the fine powder, but in the case of diantimony pentoxide, 3.8 × 10 ⁻⁷ g / cm ²
~ 7.6 × 10 ^-4 g / cm ² , more preferably 1.1 × 10 ^-5 g / cm ² ~ 3.
8 × 10 ⁻⁵ g / cm ² .

As a means for interposing fine powder between the magnetic ribbons, a method of winding or laminating fine powder while spraying the magnetic ribbon on the magnetic ribbon can be exemplified. As another method, the fine powder as described above is used,
An example of a method in which a dispersion obtained by dispersing in a polymer solution or a polymer dispersion or a mixture of both, particularly a method of attaching an insulation treatment solution as a colloid solution to at least one surface of a magnetic ribbon, and winding or laminating the same. it can.

A polymer solution used in such an insulating solution is formed by dissolving a polymer compound in a volatile liquid. As the volatile liquid, specifically, for example, as an inorganic solvent, water, aqueous ammonia, etc., as an organic solvent, toluene, xylene, lower alcohol, gasoline, kerosene,
Hexane, and aromatic and aliphatic organic solvents and the like are also included. In addition, these may be used independently and may be used in mixture as much as possible.

As the polymer compound used by being dissolved in such a volatile liquid, a nonionic substance which does not substantially coagulate the fine powder in a dispersion system is desirable. For example, specifically,
Examples include polyethylene glycol, carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid, polymethyl acrylate, and acrylic acid / silicon compound copolymer. In addition, high molecular compounds such as acrylic, urethane, epoxy, and vinyl acetate are also used.

However, the polymer compound actually used is selected according to the volatile liquid used among the above, and even when the volatile liquid is volatilized, a polymer compound having adhesiveness is still preferable. For example, when toluene is used as the volatile liquid, an acrylic, urethane, or epoxy compound may be used. When water is used as the volatile liquid, polyethylene glycol, polyvinyl alcohol and the like are preferable.

Further, the ratio of the polymer compound is 0.
The content is preferably 1% to 10% by weight. When the proportion of the polymer compound is in this range, the dispersion may have an appropriate viscosity.

As the polymer dispersion liquid used in the insulating treatment liquid, the same liquid as the volatile liquid used in the polymer solution can be used as a dispersion medium. Examples of the polymer compound used by being dispersed in such a volatile liquid include fine powders of a polyolefin-based resin such as a thermoplastic elastomer, a low-density polyolefin, an ionomer, a vinyl acetate-based copolymerized polyolefin, and a low-molecular-weight polyolefin. The particle size of the resin fine powder is preferably 5 μm or less, and the amount of dispersion in the volatile liquid is preferably about 0.1 to 10% by weight based on the total amount.

More specifically, water (95% by weight) has an average particle size of 4 μm.
polymer dispersion in which 5% by weight of a thermoplastic elastomer fine powder of 5 m is dispersed, 5% by weight of a low-density polyolefin fine powder having an average particle size of 5 μm in water (95% by weight), water (95% by weight) %) And 10% by weight of an ionomer fine powder having an average particle size of 0.5 μm or less, and 5% by weight of a vinyl acetate copolymer polyolefin fine powder having an average particle size of 5 μm or less in water (95% by weight). And a polymer dispersion obtained by dispersing 5% by weight of a low-molecular-weight polyolefin fine powder having an average particle diameter of 2 to 5 μm in water (95% by weight).

Further, the above-mentioned polymer solution and polymer dispersion may contain additive substances such as a surfactant, an emulsifying aid, and a dispersing aid. Further, a polymer solution and a polymer dispersion may be used as a mixture.

The proportion of fine powder dispersed in such a polymer solution or polymer dispersion or a mixture thereof is a polymer solution,
It varies greatly depending on the type of polymer dispersion and fine powder,
In general, it is often preferable that the amount be 0.1% by weight to 60% by weight based on the entire dispersion. Among them, for example, when the fine powder is diantimony pentoxide and the volatile liquid is toluene, diantimony pentoxide is preferably used at a ratio of 0.1 to 30% by weight based on the entire dispersion. The proportion of diannmonium pentoxide, for example, about 3% by weight is sufficiently effective. Such an insulating treatment liquid is applied to a magnetic ribbon, and there is almost no decrease in the space factor of the magnetic core on which the insulating layer is formed. Does not deteriorate.

In producing the insulating treatment liquid, the method for dispersing the fine powder may be, for example, a dispersion method or an aggregation method. In the case of the dispersion method, a mechanical dispersion method, an electric dispersion method, or a peptization method may be used. In the case of the coagulation method,
Any of a reduction method, an oxidation method, a double decomposition method, and a solubility reduction method may be used.

In order to obtain the insulation treatment liquid, a dispersion system is formed in advance by using a polymer solution or a polymer dispersion liquid in which a polymer compound is mixed in the production of such a dispersion liquid, and this is used as the insulation treatment liquid. The fine powder as described above may be mixed in the production process of the polymer solution or the polymer dispersion. Further, a polymer compound may be dissolved or dispersed in a volatile liquid in which fine powder is dispersed.

When applying the insulating treatment liquid to the magnetic ribbon as described above, the thickness at the time of application is preferably set to 10 μm or less. With this thickness, the amount of fine powder adhering to the magnetic ribbon is 10 ⁻⁷ cm ³ to 2 × 10 ⁻⁴ c per unit area (1 cm ² ) of the magnetic ribbon.
m ³ , depending on conditions, may be 3 × 10 ⁻⁶ cm ³ to 10 ⁻⁵ cm ³ .

Usually, the magnetic ribbon coated with the insulating solution as described above is further forcibly or spontaneously dried to volatilize the volatile liquid, and the fine powder is adhered to the magnetic ribbon or the like via the remaining polymer compound.

Further, in order to volatilize the volatile liquid, a drying furnace is preferably used, and drying is generally performed at 100 ° C. or less.

Such a magnetic ribbon to which fine powder is attached, the magnetic core having fine powder interposed between the ribbons is preferably at a temperature of 300 to 600 ° C, more preferably at 380 to 410 ° C for the main purpose of strain relief, and 0.5 to 0.5 ° C.
Annealing is performed for up to 5 hours, more preferably 2 to 4 hours. This annealing may be performed after winding or laminating the ribbon to form a magnetic core, or may be performed in the state of the ribbon, especially when annealing at a temperature higher by 10 to 50 ° C. than the Curie point, Good characteristics at high frequency can be obtained. Note that annealing may be performed in a magnetic field or without a magnetic field.

When the insulating treatment liquid is applied to the magnetic ribbon, if annealing is performed thereafter, the polymer compound is burned off, and the insulating fine powder is interposed and held between the magnetic ribbon layers.

When the wound or laminated amorphous magnetic core is annealed, linear expansion does not affect the magnetic core because the fine powder interposed between the ribbons is a powder. Rather, it has the effect of absorbing the stress associated with the shrinkage of the amorphous ribbon.

Furthermore, when the magnetic ribbon or the magnetic core is annealed, the surface of the magnetic ribbon is reliably oxidized due to the presence of the oxidizing inorganic substance. Control of the growth of the oxide film as compared to the case where only an oxidizing atmosphere is formed in the furnace by the mixed gas of oxygen, the mixed gas of oxygen and the inert gas, the inert gas containing moisture, etc. And the insulation can be improved.

Of course, annealing may be performed under an inert gas atmosphere,
Annealing can be performed in an oxidizing atmosphere together with the presence of the oxidizing inorganic substance, and this is more preferable in forming an oxide film.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

In the apparatus shown in FIG. 3, Allied activation of amorphous ribbons (1a), 2605S-2 ( Fe 78 -B 13 -Si 9, 1 ( atomic%)
(0 mm width) is immersed in a colloidal solution of diantimony pentoxide (2) in order, and when it is pulled up, the excess solution is dropped with a pair of bar coaters (3), and the hot air dryer (4)
The ribbon with fine powder (1b) was wound up while drying with hot air. The diantimony pentoxide colloid solution (2) uses toluene as a solvent and disperses 3% by weight of diantimony pentoxide in 97% by weight of toluene.

Next, as shown in FIG. 4, a ribbon with fine powder (1b)
Was sequentially fed through a roller (5), and wound while applying tension at the final stage to form an amorphous magnetic core (6). Then, a plurality of magnetic cores having the same dimensions were formed, and each was annealed at 430 ° C. for 2 hours in nitrogen.

The frequency characteristics of the iron loss and the frequency characteristics of the magnetic permeability of each of the obtained magnetic cores were measured when a magnetic field of 5 mOe was applied.

The following examples are based on the above, and the comparative examples show the untreated magnetic ribbon in nitrogen for comparison.
The case where annealing is performed at 0 ° C. for 2 hours is shown.

<Examples> (a) Magnetic core; Toroidal core wound with the above magnetic ribbon Inner diameter = 23.0 mm Outer diameter = 37.0 mm Height = 15.0 mm Mass = 63.0 g Material density = 7.18 g / cm ³ Volume = 8.77 × 10 ^-6 (m ³ ) Effective area = 9.31 × 10 ^-5 (m ² ) Average magnetic path length = 9.43 × 10 ^-2 (m) Space factor = 88.7% (Ratio of ribbon to total volume) ) Tension when winding magnetic ribbon = 0.8kg (b) Coated solution; organic solvent = 100% by weight of water Fine powder = 40% by weight of diantimony pentoxide (c) Annealing condition Atmosphere = Nitrogen heating condition = 390 ° C Time = 2 (hr) (e) Results * Iron loss: 1.0 W / kg at 10 kHz, 0.1 T 29 W / kg at 100 kHz, 0.1 T * Frequency characteristics of permeability; 1 wound on the core shown in Fig. 1 The number of turns of the secondary winding is 12 Measurement magnetic field = 5 mOe Measurement current = 2.21 mA <Comparative example> (a) Magnetic core: Troy wound with a magnetic ribbon to which diantimony pentoxide is not attached -Core in diameter = 23.0 mm outer diameter = 37.0 mm Height = 15.0 mm Weight = 63.0 g material density = 7.18 g / m ³ body product ^{= 8.77 × 10 -6 (m 3} ) Effective area = 9.31 × 10 ^{- 5} (m ² ) Average magnetic path length = 9.43 × 10 ^-2 (m) Space factor = 88.7% (Ratio of ribbon to total volume) Tension when winding magnetic ribbon = 0.8 kg (b) Annealing condition Atmosphere = Heating condition in nitrogen = 430 ° C Time = 2 (hr) (c) Result * Iron loss: 2.7W / kg at 10kHz, 0.1T 56W / kg at 100kHz, 0.1T * Frequency characteristics of permeability; Fig. 2 The number of turns of the primary winding wound on the core shown in Fig. 12 is 12 Measurement magnetic field = 3 mOe Measurement current = 1.33 mA From the results above, the iron loss at 10 kHz in the untreated state of the comparative example is 2.7 W / kg. On the other hand, the case of the embodiment is as low as 1.0 W / kg, and in the frequency region at 100 kHz, the case of the comparative example is 56 W / kg, whereas the case of the embodiment is 29 W / kg.
A low value of W / kg was chosen.

Also, as can be seen by comparing FIGS. 1 and 2, extremely high values could be obtained for the magnetic permeability.

〔The invention's effect〕

In the present invention, since the above-described configuration is employed, it is possible to obtain a magnetic core that satisfies both the improvement in iron loss characteristics and the improvement in magnetic permeability while minimizing a decrease in space factor and securing insulation between ribbon layers. it can.

[Brief description of the drawings]

FIG. 1 is a graph showing a change in frequency and magnetic permeability in an example of the present invention, FIG. 2 is a graph showing a change in frequency and magnetic permeability in a comparative example, and FIG. FIG. 4 is a schematic view showing an adhesion processing apparatus, and FIG. 4 is an explanatory view showing a means for manufacturing a toroidal magnetic core. 1a: Magnetic ribbon (untreated), 1b: Magnetic ribbon with fine powder, 2 ... Colloidal solution of fine powder, 3 ... Bar coater, 4 ... Hot air dryer, 5 ... Roller, 6 ... Magnetic core.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-110606 (JP, A) JP-B-62-37114 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 1 / 18,41 / 02

Claims (5)

(57) [Claims] 1. A non-magnetic fine powder made of an oxidizing inorganic substance having an insulating property on the surface of a magnetic ribbon, and the unit area (cm ² )
Per minute in the range of 10 ⁻⁷ cm ^{3 to} 2 × 10 ⁻⁴ cm ³ , and annealing in this state to form an air layer using the fine powder as a spacer between the magnetic ribbon laminates. Manufacturing method of magnetic core. 2. The method according to claim 1, wherein one or both of diantimony pentoxide and antimony trioxide are used as the oxidizing inorganic substance. 3. The method according to claim 1, wherein the magnetic ribbon is made of an amorphous metal. 4. The method for producing a magnetic core according to claim 1, wherein the diameter of the fine powder is 10 nm to 2 μm. 5. The method according to claim 1, wherein the magnetic core is annealed in an oxidizing atmosphere at a temperature of 300 to 600 ° C. for 0.5 to 5 hours.