JPH10199720A - Method for forming induced magnetic anisotropy of iron group amorphous magnetic alloy ribbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form an induced magnetic anisotropy and also to easily control its orientation and magnitude, by adjusting a sol-gel solution of a specific metal oxide, coating the sol-gel solution on the surface of an iron based amorphous magnetic alloy ribbon, for drying and thermal treatment. SOLUTION: A sol/gel coating solution 4 of metal oxide selected among MgO, Al2 O3 , SiO2 , BaO, MgO.Al2 O3 , MgO-SiO2 , CaO.Al2 O3 , BaO.Al2 O3 , and SrO.Al2 O3 , is adjusted. Then, the ribbon of a bobbin 1 is, by rotation of a bobbin 7, moved at a constant speed toward the bobbin 7. Here, the ribbon is allowed to pass the coating solution 4 provided in a coating chamber 5 so that the coating solution 4 is adsorbed and coated on the surface of ribbon, then dried through an electric furnace 6. Then, the coated ribbon is thermally processed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an induced magnetic anisotropy on an iron-based amorphous magnetic alloy ribbon.

[0002]

2. Description of the Related Art Magnetic materials must control the magnetic properties of the materials so as to have optimum characteristics according to the purpose of use. One of the most frequently used methods for controlling magnetic properties is formation or control of induced magnetic anisotropy. Induced magnetic anisotropy is based on the fact that the normal arrangement of atomic pairs deviates from the irregular ones,
ing) is thought to form.
It is known that such an induced magnetic anisotropy is particularly well formed of an amorphous material rather than a crystalline material. From such a viewpoint, researches for obtaining characteristics suitable for application by giving induced magnetic anisotropy to an amorphous magnetic alloy ribbon have been actively conducted.

[0003] As a method for imparting induced magnetic anisotropy,
Heat treatment while applying a magnetic field (in-field heat treatment)
Heat treatment while applying stress (stress heat treatment method). If necessary, both the heat treatment in the magnetic field and the stress heat treatment may be used together.

The heat treatment in a magnetic field is a widely used method, in which induced magnetic anisotropy is formed only at a temperature lower than the Curie temperature, and the direction of the induced magnetic anisotropy is the same as the direction of the applied magnetic field. Become. The advantage of this method is that there is no particular limitation on the shape of the material. For example, a ribbon-shaped material or a core made of this material (toroidal core)
It can be applied to all kinds of materials such as. But,
Induced magnetic anisotropy obtained by using a heat treatment in a magnetic field is easily formed with a cobalt-based amorphous magnetic alloy ribbon,
It is not formed of an iron-based amorphous magnetic alloy ribbon, and even when induced magnetic anisotropy is formed, the size thereof is very small.

On the other hand, the stress heat treatment method can form induced magnetic anisotropy regardless of the heat treatment temperature. If the heat treatment temperature is above the Curie temperature,
Induced magnetic anisotropy is formed by minute movement of atoms by elastic force, and when the temperature is below the Curie temperature, induced magnetic anisotropy is formed by minute movement of atoms by elastic force and magnetoelastic interaction. You. In this case, the direction of the induced magnetic anisotropy is determined by the material structure, the type of stress, and the sign of magnetic deformation. However, a disadvantage of the stress heat treatment method is that the shape of the material is largely limited. For example, it is possible to apply stress to a linear ribbon material, but it is very difficult to apply stress to a toroidal core that is practically important.

Therefore, in the case of a toroidal core, it is almost impossible to form induced magnetic anisotropy by a stress heat treatment method. Also, in the case of a linear ribbon material, it is easy to apply a tensile stress, but it is not easy to apply a compressive stress.

[0007]

SUMMARY OF THE INVENTION The present invention provides a method for easily forming induced magnetic anisotropy and easily controlling its direction and size in an iron-based amorphous magnetic alloy material. To provide.

[0008]

Means for Solving the Problems The present inventors have found that the above object can be achieved by forming an oxide film on the surface of an iron-based amorphous magnetic alloy ribbon, and have completed the present invention. I came to.

The present invention provides a method for forming induced magnetic anisotropy on an iron-based amorphous magnetic alloy ribbon, comprising the following steps. A) MgO, Al ₂ O ₃ , SiO ₂ , BaO, MgO
Al ₂ O ₃ , MgO · SiO ₂ , CaO · Al ₂ O ₃ ,
Preparing a sol-gel solution of a metal oxide selected from the group consisting of BaO.Al ₂ O ₃ and SrO.Al ₂ O ₃ ; B) coating the sol-gel solution on the surface of an iron-based amorphous magnetic alloy ribbon C) drying said coated ribbon;
And D) heat treating the dried ribbon.

When an oxide film is formed on the surface of an iron-based amorphous magnetic alloy material by the method of the present invention, stress is generated in the magnetic material due to a difference in thermal expansion coefficient between the magnetic material and the oxide. However, the stress imparts induced magnetic anisotropy to the magnetic material by magnetoelastic interaction, elastic action, or both. Therefore, the present invention is similar in principle to the stress heat treatment method, but is characterized in that unlike the stress heat treatment method, there are no restrictions due to the shape of the material.

According to the present invention, it is possible to control the type and magnitude of the stress induced in the magnetic material by the type of the oxide film, thereby controlling the direction and magnitude of the induced magnetic anisotropy. It will be very easy to do. Therefore, by properly selecting the type of oxide, magnetic characteristics suitable for use can be obtained. For example, there are fields in which it is required to make the magnetic hysteresis curve as flat as possible to reduce the squareness ratio, and for applications of choke coils, BaO, CaO.Al ₂ O ₃ , BaO.Al
It is desirable to form a ₂ O ₃ or SrO.Al ₂ O ₃ coating.

In the present invention, the oxide used for the iron-based amorphous magnetic alloy ribbon coating can be obtained by a sol-gel method. In the sol-gel method, ultrafine particles are first created using inorganic compounds as starting materials, then a colloid route is made into a bulk sample through the sol and gel states, and a sol state is formed by polymerization of organometallic compounds through hydrolysis. There is a route to make fiber, film, bulk gel state and heat it to produce the product. This process is used to form ultrafine particles or thin films by the manufacturing method, and high chemical purity, uniform molecular distribution, easy adjustment of the stoichiometric ratio and crystallization at relatively low temperature. Because of the merit that it is possible, it is frequently used in the manufacturing process of ceramic materials. The starting material is usually
A metal alkoxide [M (OR) _2X ] is used, and the metal and oxygen are linked by a hydrolysis reaction of water to change into _a polymer structure [“M _{a Ob} (OR _c )”]. It will vary completely the metal oxide [M _n O _X]. This process can be simply represented by the following reaction formula 1. _{M (OR) 2X + x ·} H 2 O → "M a O b (OR c)" → MO
_X ＋ 2x ・ ROH

In the present invention, the single metal oxide M
A sol-gel solution composed of gO, Al ₂ O ₃ , SiO ₂ or BaO is obtained by obtaining an alcohol solution of a metal alkoxide corresponding to a target metal oxide, and then adding
It is prepared by reacting anhydrous or hydrous alcohol.

On the other hand, MgO.Al which is a composite metal oxide
₂ O ₃ , MgO.SiO ₂ , CaO.Al ₂ O ₃ , Ba
As a sol-gel solution of O.Al ₂ O ₃ or SrO.Al ₂ O ₃ , alcohol solutions of two types of metal alkoxides corresponding to the target metal oxide are obtained, and the two types of solutions are mixed. It is prepared by reacting the mixture with anhydrous or hydrous alcohol.

The alcohol solution of the metal alkoxide used in the present invention can be prepared from the corresponding metal or metal alkoxide.

As an alcohol solution of magnesium alkoxide, an alcohol such as methanol, ethanol, n-propanol, i-
Propanol, n-butanol, sec-butanol, te
Magnesium methoxide, magnesium ethoxide, magnesium n-propoxide, magnesium i-propoxide, magnesium n-butoxide, magnesium n-butoxide, magnesium methoxide, magnesium ethoxide, and magnesium methoxide obtained by directly adding rt-butanol or 2-methoxyethanol little by little. sec −
A solution of butoxide, magnesium tert-butoxide or magnesium methoxy ethoxide can be used.
Further, the alkoxide of this magnesium alkoxide can be converted and used as another magnesium alkoxide. For example, magnesium methoxy ethoxide solution includes magnesium methoxide, magnesium ethoxide, magnesium n-propoxide, magnesium i-propoxide, magnesium n-butoxide,
Magnesium sec-butoxide or magnesium te
It can be prepared by reacting rt-butoxide with a 2-methoxyethanol solution in the form of a powder or in the form of an alcohol solution thereof, and subjecting it to an exchange reaction between an alcohol and an alkoxide (that is, an alcoholysis reaction).

As an alcohol solution of barium alkoxide, an alcohol such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol is added little by little to a barium metal chip. Barium methoxide, barium ethoxide, barium n-propoxide, barium i-propoxide, barium n-butoxide, barium sec-butoxide, barium tert-butoxide or barium 2- obtained by directly reacting a metal with an alcohol. Methoxy ethoxide can be used. Further, the alkoxide of the barium alkoxide can be converted to be used as another barium alkoxide. For example, barium methoxy ethoxide solution, barium methoxide, barium ethoxide, barium n-propoxide, barium i-propoxide, barium n-butoxide, barium sec-butoxide or barium tert-butoxide, in powder form or alcohol thereof It can be prepared by an alcoholysis reaction in which it is reacted with a 2-methoxyethanol solution in the form of a solution.

As an alcohol solution of aluminum alkoxide, an alcohol such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-
Aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum i obtained by adding butanol, tert-butanol or 2-methoxyethanol little by little and directly reacting the metal with the alcohol.
-Propoxide, aluminum n-butoxide, aluminum sec-butoxide, aluminum tert-butoxide or aluminum methoxyethoxide can be used. Further, the aluminum alkoxide can be converted to an alkoxide and used as another aluminum alkoxide. For example, aluminum methoxy ethoxide solution, aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum i-propoxide, aluminum n-butoxide, aluminum sec-butoxide or aluminum tert-butoxide, powder form or alcohol thereof It can be prepared by an alcoholysis reaction in which it is reacted with a 2-methoxyethanol solution in the form of a solution.

As the alcohol solution of silicon alkoxide, tetraalkyl orthosilicate (Si (O
R) ₄ ) an alcohol such as methanol, ethanol,
n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol is added and reacted to obtain silicon methoxide, silicon ethoxide, silicon n-propoxide, silicon i-propoxide. , Silicon n-butoxide, silicon
A sec-butoxide, silicon tert-butoxide or silicon methoxy ethoxide solution can be used.

As the alcohol solution of calcium alkoxide, an alcohol such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-
Calcium methoxide, calcium ethoxide, calcium n- obtained by adding butanol or 2-methoxyethanol little by little and directly reacting the metal with the alcohol.
Propoxide, calcium i-propoxide, calcium n-butoxide, calcium sec-butoxide, calcium tert-butoxide or calcium methoxy ethoxide solutions can be used. Further, the alkoxide of this calcium alkoxide can be converted and used as another calcium alkoxide. For example,
The calcium methoxy ethoxide solution includes calcium methoxide, calcium ethoxide, calcium n-propoxide, calcium i-propoxide, calcium n-
It can be prepared by reacting butoxide, calcium sec-butoxide or calcium tert-butoxide with a 2-methoxyethanol solution in the form of a powder or its alcohol solution.

As the strontium alkoxide alcohol solution, an alcohol such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol is added little by little to a strontium metal chip. , Strontium methoxide, strontium ethoxide, strontium n-propoxide, strontium i-propoxide, strontium n-butoxide, strontium sec-butoxide, strontium sec-butoxide, strontium tert-
Butoxide or strontium methoxy ethoxide can be used. Further, the strontium alkoxide can be converted to another strontium alkoxide for use. For example, a strontium methoxy ethoxide solution is strontium methoxide, strontium ethoxide, strontium n
-Propoxide, strontium i-propoxide, strontium n-butoxide, strontium sec-butoxide or strontium tert-butoxide;
It can be prepared by an alcoholysis reaction of reacting a 2-methoxyethanol solution in the form of a powder or an alcohol solution thereof.

In the method of the present invention, the alcohols used in steps (A) and (B) may be the same or different, such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec −
It can be selected from butanol, tert-butanol or 2-methoxyethanol.

In the embodiment of the present invention, an iron-based amorphous magnetic alloy ribbon is coated with an oxide using the coating apparatus shown in FIG. Bobbin (1) with ribbon (3)
And connected to the bobbin (7) via several pulleys (2) (FIG. 1). The ribbon mounted on the bobbin (1) moves at a constant speed in the direction of the bobbin (7) as the bobbin (7) rotates. By passing the ribbon (3) through the coating solution (4) installed in the coating chamber (5) under an atmosphere of an inert gas (eg, argon or nitrogen), the coating solution is adsorbed on the surface of the ribbon. . The ribbon on which the coating solution is uniformly adsorbed and coated is dried in an electric furnace (6). The oxide-coated ribbon is wound up on a bobbin (7).

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the iron-based amorphous magnetic alloy ribbon of the present invention and its characteristics will be specifically described with reference to examples, but the present invention is not limited to the following examples.

EXAMPLE 1 Magnesium ethoxide [Mg (OCH ₂ CH ₃ ) ₂ ] powder was mixed with excess 2-methoxyethanol [CH ₃ OCH ₂ C].
H ₂ OH], refluxed under an argon gas atmosphere,
Magnesium methoxy ethoxide was obtained. Using a vacuum trap to remove excess ethanol present in the solution,
Further, 2-methoxyethanol was added in a glove box to accurately prepare a 0.5 M solution (first solution). Next, a 0.5 M ethanol solution containing water was prepared (second solution). The same volumes of the first solution and the second solution were gradually mixed while taking care not to cause precipitation to prepare a final coating solution.

Next, an oxide film was formed from the above coating solution using the coating apparatus shown in FIG. Metglas 2605S3A (composition Fe _76.5 Cr ₂ B ₁₆ Si ₅ ) which is a ribbon material for coating the bobbin (1) in FIG.
After mounting C _0.5 ) (3), it was connected to the bobbin (7) through several Teflon pulleys (2). The ribbon of the bobbin (1) moves at a constant speed in the direction of the bobbin (7) as the bobbin (7) rotates. By passing the ribbon through the coating solution (4) installed in the coating chamber (5) under an argon atmosphere, the coating solution was adsorbed and coated on the surface of the ribbon. The ribbon, on which the coating solution was uniformly adsorbed and coated on the surface, was dried through a non-inductive winding electric furnace (6) so that no magnetic field was generated. The temperature of the electric furnace was 200 ° C.

The thickness of the coating oxide film was measured using a digital micrometer. After laminating 10 to 20 layers of the ribbon to improve the accuracy of the measurement, the thickness of the lamination was measured, and the thickness of the coating oxide was calculated by dividing by the number of laminated ribbons. The thickness of one MgO film was 0.7 μm.

After the oxide-coated ribbon is wound into 50 layers on an aluminum bobbin having an inner diameter of 19 mm, 435 ° C. is applied using an electric furnace wound in a non-inductive manner under a nitrogen atmosphere so that a hot wire does not generate a magnetic field. After the heat treatment for 2 hours, the magnetic properties were examined. Regarding the magnetic properties, the change of the effective magnetic permeability according to the magnetic hysteresis curve and the frequency was measured for the sample on which the oxide film was not formed and the sample on which the oxide film was formed by the above method.

The magnetic hysteresis curve was measured using a magnetic hysteresis analyzer (Model TRF-5AH1 manufactured by Toei Kogyo Co., Ltd.). FIG. 2 shows the magnetic hysteresis curve of the sample in which the oxide film was not formed, and FIG. 3 shows the magnetic hysteresis curve of the sample in which the MgO film was formed according to the present invention. As can be seen from the results of FIGS. 2 and 3, the squareness ratio of the sample without the oxide film was 0.40, whereas the squareness ratio of the sample with the MgO film formed according to the present invention was 0. Was 0.74.

The effective magnetic permeability was measured using an impedance analyzer (Model 4219A, manufactured by Hewlett Packard) under an applied magnetic field of 10 mOe. FIG. 12 shows the result. As can be seen from FIG.
The effective magnetic permeability of the sample on which the film was formed was higher than that of the uncoated sample at a frequency of less than 100 kHz, but was substantially equal in the high-frequency region of 100 kHz or more.

Example 2 As a first solution, 2-methoxyethanol was added little by little to a barium metal chip, and a 0.5M barium methoxyethoxide solution obtained by directly reacting a metal with an alcohol was used to prepare a final coating solution. Except for the preparation, an oxide film was formed in the same manner as in Example 1. The oxide thus formed was BaO, and the thickness of the oxide film was 0.4 μm.
m.

Using the same method as in Example 1, the magnetic hysteresis curve and the effective magnetic permeability were measured. The results are shown in FIGS. 4 and 12, respectively.

As can be seen from the results shown in FIGS. 2 and 4, the squareness ratio of the sample on which the oxide film was formed according to the present invention was greatly reduced. Specifically, the squareness ratio of the sample in which the oxide film was not formed was 0.4, whereas the squareness ratio of the sample according to the present invention was Ba.
The squareness ratio of the sample on which the O film was formed was 0.20.

As can be seen from FIG. 12, according to the present invention, B
The effective magnetic permeability of the sample on which the aO coating is formed shows a smaller value in the frequency range of 400 kHz or less than that of the uncoated sample. However, since the decrease in the effective magnetic permeability due to the frequency is very small, the frequency of 400 to 100 kHz is low. The effective magnetic permeability was almost constant in the range.

Example 3 Aluminum isopropoxide @ Al was used as the first solution.
[OCH (CH ₃ ) ₂ ] ₃ } is mixed with 2-methoxyethanol and refluxed at a temperature of 85 ° C. for 90 minutes to prepare a 0.5 M aluminum methoxy ethoxide solution. As a second solution, anhydrous ethanol is used. An oxide film was formed in the same manner as in Example 1 except that the final coating solution was prepared. The oxide thus formed was Al ₂ O ₃ and the thickness of the oxide film was 0.39 μm.

Using the same method as in Example 1, the magnetic hysteresis curve and the effective magnetic permeability were measured. The results are shown in FIGS. 5 and 12, respectively.

As can be seen from FIGS. 2 and 5, the squareness ratio of the sample on which the oxide film was formed according to the present invention was slightly reduced.
Specifically, the squareness ratio of the sample on which the oxide film was not formed was 0.40, whereas the squareness ratio of the sample on which the Al ₂ O ₃ film was formed according to the present invention was 0.34. Was.

As can be seen from FIG. 12, the effective magnetic permeability of the sample on which the Al ₂ O ₃ coating was formed according to the present invention was higher in all frequency ranges than the sample on which the oxide coating was not formed. Indicated.

Example 4 5.0 g (6.330 ml) of ethanol, 4.3 of H ₂ O
A solution obtained by mixing 25 g and 0.3 ml of HCl was added to 6.0 solution.
12.50 diluted with 6 g (7.67 ml) of ethanol
g of TEOS (tetraethylorthosilicate) solution, and then stirred for 40 minutes while maintaining the temperature at 40 ° C. in a thermostat to prepare a coating solution in the same manner as in Example 1 except that the coating solution was prepared. An oxide film was formed on the amorphous magnetic alloy ribbon. The oxide thus formed was SiO ₂ and the thickness of the oxide film was 0.65 μm.

Using the same method as in Example 1, the magnetic hysteresis curve and the effective magnetic permeability were measured. The results are shown in FIGS. 6 and 12, respectively.

As can be seen from FIGS. 2 and 6, the squareness ratio of the sample on which the oxide film was formed according to the present invention was increased. Specifically, the squareness ratio of the uncoated sample was 0.40.
The squareness ratio of the sample on which the SiO ₂ coating was formed according to the present invention was 0.57.

As can be seen from FIG. 12, the sample formed with the SiO ₂ film according to the present invention exhibited a lower effective magnetic permeability in all frequency ranges than the sample not coated.

Example 5 A magnesium methoxy ethoxide solution prepared using the same method as in Example 1 and an aluminum methoxy ethoxide solution prepared using the same method as in Example 3 were mixed in equimolar amounts. An oxide film was formed in the same manner as in Example 1, except that the first solution was produced by refluxing, and a coating solution was prepared using anhydrous ethanol as the second solution. The oxide thus formed is MgO · Al
₂ O ₃ and the thickness of the oxide film was 0.75 μm.

The magnetic hysteresis curve and the effective magnetic permeability were measured in the same manner as in Example 1. The results are shown in FIGS. 7 and 13, respectively.

As can be seen from the results shown in FIGS. 2 and 7, the squareness ratio of the sample on which the MgO.Al ₂ O ₃ film was formed according to the present invention was greatly increased. Squareness ratio of the sample specifically were not formed in the oxide coating whereas a 0.40 squareness ratio sample formed a MgO · Al ₂ O ₃ film by the present invention is 0.71 Met.

As can be seen from FIG. 13, the effective magnetic permeability of the sample on which the oxide film was formed according to the present invention showed a higher value in all frequency ranges than the sample without the coating.

Example 6 2-Methoxyethanol was added to calcium methoxide [Ca (OCH ₃ ) ₂ ] and the mixture was refluxed to obtain a 0.5M calcium methoxy ethoxide solution.
The aluminum methoxy ethoxide solution obtained using the same method as in Example 1 was mixed in an equimolar amount, and then refluxed to prepare a first solution. An oxide film was formed in the same manner as in Example 1 except that a coating solution was obtained using anhydrous ethanol as the second solution. The oxide thus formed was CaO.Al ₂ O ₃ , and the thickness of the oxide film was 1.92 μm.

Using the same method as in Example 1, the magnetic hysteresis curve and the effective magnetic permeability were measured. The results are shown in FIG.
And FIG.

As can be seen from the results shown in FIGS. 2 and 8, the squareness ratio of the sample on which the CaO.Al ₂ O ₃ coating was formed according to the present invention was slightly reduced. Specifically, the squareness ratio of the uncoated sample was 0.40, but the CaO.A
The squareness ratio of the sample on which the l ₂ O ₃ coating was formed was 0.34.

As can be seen from FIG. 13, the sample formed with the CaO.Al ₂ O ₃ coating according to the present invention has a lower effective magnetic permeability at a frequency of about 300 kHz or less than the sample not coated. , Higher values at higher frequencies.

Example 7 A 0.5M strontium methoxy ethoxide solution synthesized by adding 2-methoxyethanol little by little to a strontium metal chip and directly reacting the metal with an alcohol was prepared by using the same method as in Example 3. The prepared aluminum methoxy ethoxide solution was mixed in an equimolar amount and then refluxed to obtain a first solution. Except that the final coating solution was obtained using absolute ethanol as the second solution,
An oxide film was formed in the same manner as in Example 1. The formed oxide was SrO.Al ₂ O ₃ , and the thickness of the oxide film was 1.68 μm.

Using the same method as in Example 1, the magnetic hysteresis curve and the effective magnetic permeability were measured. The results are shown in FIGS. 9 and 13, respectively.

As can be seen from the results shown in FIGS. 2 and 9, the squareness ratio of the sample on which the SrO.Al ₂ O ₃ coating was formed according to the present invention was greatly reduced. Squareness ratio of the sample specifically uncoated whereas a 0.40 squareness ratio sample formed a SrO · Al ₂ O ₃ film by the present invention was 0.16.

As can be seen from FIG. 13, the sample formed with the SrO.Al ₂ O ₃ coating according to the present invention has a smaller effective magnetic permeability in the frequency region of 700 kHz or less than the sample not coated. However, since the decrease in the effective magnetic permeability due to the frequency was very small, the effective magnetic permeability was almost constant up to the frequency of 100 kHz.

Example 8 A barium methoxy ethoxide solution obtained by using the same method as in Example 2 and an aluminum methoxy ethoxide solution obtained by using the same method as in Example 3 were mixed in equimolar amounts, and then refluxed. Then, an oxide film was formed in the same manner as in Example 1 except that a first solution was prepared and a coating solution was prepared using anhydrous ethanol as a second solution. The oxide thus formed is BaO.Al ₂ O ₃ ,
The thickness of the oxide film was 1.80 μm.

The magnetic hysteresis curve and the effective magnetic permeability were measured in the same manner as in Example 1. The results are shown in FIG.
And FIG.

As can be seen from the results shown in FIGS. 2 and 10, the squareness ratio of the sample on which the BaO.Al ₂ O ₃ coating was formed according to the present invention was greatly reduced. Squareness ratio of the sample specifically uncoated whereas a 0.40 squareness ratio sample formed a BaO · Al ₂ O ₃ film by the present invention was 0.17.

As can be seen from FIG. 13, the sample formed with the BaO.Al ₂ O ₃ coating according to the present invention has a smaller effective magnetic permeability in the frequency range of 500 kHz or less than the sample not coated. However, since the decrease in effective magnetic permeability due to frequency is very small,
It showed a nearly constant time permeability up to the z frequency.

Example 9 A 0.5M silicon methoxy ethoxide solution obtained by mixing 2-methoxyethanol with TEOS and refluxing was mixed with a magnesium methoxy ethoxide solution obtained by the same method as in Example 1. After mixing in equimolar amounts, the mixture was refluxed to prepare a first solution, and an oxide film was formed in the same manner as in Example 1 except that a coating solution was prepared using anhydrous ethanol as a second solution. The oxide thus formed was MgO.SiO ₂ , and the thickness of the oxide film was 1.39 μm.

The magnetic hysteresis curve and the effective magnetic permeability were measured in the same manner as in Example 1. The results are shown in FIG.
And FIG.

As can be seen from the results shown in FIGS. 2 and 11, the squareness ratio of the sample formed with the MgO.SiO ₂ coating according to the present invention was slightly increased. Squareness ratio of the sample specifically uncoated whereas a 0.40 squareness ratio sample formed a MgO · SiO ₂ film by the present invention is 0.
It was 50.

[0062] Also, as can be seen from Figure 13, the effective permeability of the sample to form MgO · SiO ₂ film by the present invention shows a low value at 100kHz frequencies below as compared to samples without coating, more High values were shown in the frequency domain.

[0063]

The induced magnetic anisotropy of the iron-based amorphous magnetic alloy ribbon can be controlled over a wide range by changing the type of the oxide coating material. Therefore, the magnetic characteristics can be controlled over a wide range.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus used to form an oxide film on an iron-based amorphous magnetic alloy ribbon in the present invention.

FIG. 2 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon having no oxide film formed thereon. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 3 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which an MgO film is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 4 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which a BaO film is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 5 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which an Al ₂ O ₃ coating is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 6 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon having a SiO ₂ coating formed thereon according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 7 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which an MgO.Al ₂ O ₃ film is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 8 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which a CaO.Al ₂ O ₃ film is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 9 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which a SrO.Al ₂ O ₃ film is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 10 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which a BaO.Al ₂ O ₃ coating is formed according to the present invention. The units of the magnetic flux density and the applied magnetic field are shown in the figure.

FIG. 11 is a magnetic hysteresis curve of an iron-based amorphous magnetic alloy ribbon on which an MgO.SiO ₂ coating is formed according to the present invention. In the figure,
Indicates the unit of magnetic flux density and applied magnetic field.

FIG. 12 shows the effective magnetic permeability of an iron-based amorphous magnetic alloy ribbon having a single metal oxide film formed thereon and an iron-based amorphous magnetic alloy ribbon having no oxide film formed thereon. 5 is a semilogarithmic graph showing frequency dependence.

FIG. 13 shows the frequency of the effective magnetic permeability of an iron-based amorphous magnetic alloy ribbon having a composite metal oxide film formed thereon and an iron-based amorphous magnetic alloy ribbon having no oxide film formed thereon. Semi-log graph showing dependencies.

[Explanation of symbols]

 Reference Signs List 1 bobbin 2 pulley 3 ribbon 4 coating solution 5 coating chamber 6 electric furnace 7 bobbin

Claims (3)

[Claims] 1. A method for forming induced magnetic anisotropy on an iron-based amorphous magnetic alloy ribbon, comprising the following steps. MgO, Al ₂ O ₃ , SiO ₂ , BaO, MgO
・ Al ₂ O ₃ , MgO ・ SiO ₂ , CaO ・ Al ₂ O
_3. preparing a sol-gel solution of a metal oxide selected from the group consisting of BaO.Al ₂ O ₃ and SrO.Al ₂ O ₃ , coating the sol-gel solution on the surface of an iron-based amorphous magnetic alloy ribbon Drying the coated ribbon; and heat treating the dried ribbon. 2. An alcohol solution of a metal alkoxide corresponding to a target metal oxide is prepared, and the solution is reacted with anhydrous or hydrous alcohol to obtain the MgO, Al ₂
O _3, to prepare a SiO ₂ or BaO of sol gel solution, the process of claim 1. 3. MgO.Al ₂ O ₃ , MgO.SiO
₂ , CaO.Al ₂ O ₃ , BaO.Al ₂ O ₃ or Sr
A sol-gel solution of O.Al ₂ O ₃ is prepared by dissolving two kinds of metal alkoxides corresponding to a target metal oxide in the same kind of alcohol, respectively, to prepare alcohol solutions of two kinds of metal alkoxides. The method according to claim 1, wherein the two solutions are mixed, and then the mixture is reacted with anhydrous or hydrous alcohol to prepare a sol-gel solution.