KR100246014B1 - A Method of Forming Induced Magnetic Anisotropy of Amorphous Magnetic Alloy Ribbons - Google Patents

Abstract

Preparing a sol-gel solution of oxide, coating the sol-gel solution on the surface of the iron-based amorphous magnetic alloy ribbon, drying the coated iron-based amorphous magnetic alloy ribbon, and drying the coated iron-based amorphous magnetic alloy ribbon A method of forming induction magnetic anisotropy in an iron-based amorphous magnetic alloy thin ribbon comprising a step of heat treatment is provided. By appropriately selecting the type of oxide, induction magnetic anisotropy is formed, and thus direct and alternating magnetic properties can be greatly changed.

Description

A Method of Forming Induced Magnetic Anisotropy of Amorphous Magnetic Alloy Ribbons

The present invention relates to a method of forming induced magnetic anisotropy in an iron-based amorphous magnetic alloy thin ribbon.

Magnetic materials often control the magnetic properties of the material to have properties suitable for the application, and one of the most used methods for controlling the magnetic properties is induced magnetic anisotropy. Induced magnetic anisotropy is known to arise from pair ordering occurring in a particular direction, usually out of a completely irregular arrangement of atomic pairs. It is known that such induced magnetic anisotropy is particularly well formed in an amorphous phase rather than a crystalline phase. From this point of view, many studies have been conducted to obtain suitable properties for application by giving inductive magnetic anisotropy to amorphous magnetic alloy thin ribbons.

The method of giving induction magnetic anisotropy includes a method of heat treatment while applying a magnetic field (magnetic field heat treatment method) and a method of heat treatment while applying stress (stress heat treatment method). If necessary, both the magnetic field heat treatment method and the stress heat treatment method may be used.

The magnetic field heat treatment method is widely used. Induction magnetic anisotropy is formed only at a Curie temperature or lower, and the direction of induced magnetic anisotropy is the same as that of the applied magnetic field. The advantage of this method is that it is not limited to the shape of the material. For example, the present invention can be applied to both a material in the form of a thin ribbon and a material in the form of a core (toroidal core) wound thereon. However, although the induced magnetic anisotropy by the magnetic field heat treatment method is easily formed in the cobalt-based amorphous magnetic alloy thin ribbons, the induced magnetic anisotropy is not well formed in the iron-based amorphous magnetic alloy thin ribbons, and the size of the induced magnetic anisotropy is very small.

On the other hand, the stress annealing method can form induction magnetic anisotropy irrespective of the heat treatment temperature. When the heat treatment temperature is higher than the Curie temperature, the induced magnetic anisotropy is formed by the micro migration of atoms due to the elastic force. Induced magnetic anisotropy is formed by micro migration of atoms due to elastic force and magnetic elastic interaction. In this case, the direction of induced magnetic anisotropy is determined by the structure of the material, the type of stress and the sign of the magnetostriction. The disadvantage of stress heat treatment is that the shape of the material is greatly limited. For example, linear thin ribbon materials can be stressed, but it is very difficult to stress practically important toroidal cores. Therefore, in the case of the toroidal core, formation of induced magnetic anisotropy by the stress heat treatment method is almost impossible. In addition, even in the case of linear thin ribbon material, it is easy to apply tensile stress, but not compressive stress.

It is an object of the present invention to provide a method which can very easily control the direction and magnitude of induced magnetic anisotropy for iron-based amorphous magnetic alloy materials.

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

2 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon without forming an oxide film.

3 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with an MgO film according to the present invention.

4 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with a BaO film according to the present invention.

5 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with an Al ₂ O ₃ film according to the present invention.

6 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with a SiO ₂ film according to the present invention.

7 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with a MgO · Al ₂ O ₃ film according to the present invention.

8 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with a CaO · Al ₂ O ₃ film according to the present invention.

9 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with an SrO.Al ₂ O ₃ film according to the present invention.

10 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with a BaO · Al ₂ O ₃ film according to the present invention.

11 is a hysteresis curve of an iron-based amorphous magnetic alloy thin ribbon formed with an MgO.SiO ₂ film according to the present invention.

12 is a graph showing the frequency dependence of the effective permeability of iron-based amorphous magnetic alloy thin ribbons having a single oxide film formed thereon and iron-based amorphous magnetic alloy thin ribbons having no oxide film formed therein.

Figure 13 is a graph showing the frequency dependence of the effective permeability of the iron-based amorphous magnetic alloy thin ribbons formed with a double oxide film and the iron-based amorphous magnetic alloy thin ribbons without forming an oxide film according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1, 7: bobbin

2: pulley

3: beat

4: coating solution

5: coating room

6: electric furnace

The present inventors have found that the above object is achieved by forming an oxide film on the surface of an iron-based amorphous magnetic alloy thin ribbon.

According to the invention,

A) from the group consisting of MgO, Al ₂ O ₃ , SiO ₂ , BaO, MgO-Al ₂ O ₃ , MgO-SiO ₂ , CaO-Al ₂ O ₃ , BaO-Al ₂ O ₃ and SrO-Al ₂ O ₃ Preparing a sol-gel solution of the selected oxide,

B) coating the sol-gel solution on the surface of the iron-based amorphous magnetic alloy thin ribbon,

C) drying the coated iron-based amorphous magnetic alloy thin ribbon, and

D) heat treating the dried coated iron-based amorphous magnetic alloy thin ribbon

Provided is a method of forming induction magnetic anisotropy in an iron-based amorphous magnetic alloy thin ribbon.

According to the present invention, when an oxide film is formed on the surface of an iron-based amorphous magnetic alloy material, a stress is generated in the magnetic material due to a difference in the coefficient of thermal expansion between the magnetic material and the oxide, and such stress is a magnetic elastic interaction, an elastic action, or both. Both actions give magnetic magnetic anisotropy to the magnetic material. Therefore, the present invention is similar in principle to the stress heat treatment method. However, unlike the stress heat treatment method, the shape of the material is not limited.

According to the present invention, it is possible to control the kind and magnitude of the stress induced in the magnetic material according to the kind of the oxide film, and thus it is very easy to control the direction and magnitude of the induced magnetic anisotropy. Therefore, by appropriately selecting the type of oxide, it is possible to obtain magnetic properties suitable for the application. For example, in fields where the hysteresis curve is laid down as much as possible to reduce the square ratio, for example, the application of choke core is BaO, CaO Al ₂ O ₃ , BaO Al ₂ O ₃ or SrO Al ₂ O _3. It is preferable to form a film.

In the present invention, the oxide used to coat the iron-based amorphous magnetic alloy thin ribbon is produced by the sol-gel method. The sol-gel method densification process of liquid substance in which the chemical monomer, which is a molecular structure in the liquid phase, changes into an increasingly complex structure such as dimers and trimers, and becomes a colloidal sol, and the liquid phase decreases and into a gel in which colloids stick together. Say. This process is used to make ultrafine particles or thin films according to the manufacturing method, and is widely used in the ceramic manufacturing process due to the advantages of high chemical purity, uniform distribution of molecules, easy control of chemical equivalence ratio, and crystallization at relatively low temperature. . The metal alkoxide [M (OR) _2X ] is usually used as a starting material, and the metals are connected to oxygen by the hydrolysis reaction of water, and the polymer is converted into _a polymer structure ["M _a O _b (OR _c )"]. Is completely transformed into a metal oxide [MO _x ]. This process is simplified by the following scheme 1.

M (OR) _2x + _{xH 2} O → "M _a O _b (OR _c )" → MO _x + 2xROH

In the present invention, the sol-gel solution of the single component oxides MgO, Al ₂ O ₃ , SiO ₂ or BaO produces an alcohol solution of alkoxide (hereinafter referred to as "first solution") corresponding to the desired oxide, and this solution Is prepared by reacting with an alcohol containing or without water (hereinafter referred to as " second solution &quot;). On the other hand, the sol-gel solution of the double oxides MgO-Al ₂ O ₃ , MgO-SiO ₂ , CaO-Al ₂ O ₃ , BaO-Al ₂ O ₃ or SrO-Al ₂ O ₃ is applied to each component of the desired double oxide. The alcohol solution of the corresponding two alkoxides (first solution) is prepared, the two solutions are mixed with each other and the mixture is reacted with an alcohol (second solution) with or without water.

Alcohol solutions of the metals (including metalloids such as Si) alkoxides used in the present invention can be prepared from the corresponding metals or metal alkoxides.

The alcohol solution of magnesium alkoxide is directly added to the magnesium metal chip by adding alcohol, such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol in small portions. Magnesium methoxide, magnesium ethoxide, magnesium n-propoxide, magnesium i-propoxide, magnesium n-butoxide, magnesium sec-butoxide, magnesium tert-butoxide or magnesium methoxide prepared by reacting metal with alcohol A oxyethoxide alcohol solution can be used. It is also possible to convert magnesium alkoxides to other magnesium alkoxides for use. For example, the magnesium methoxyethoxide solution may be magnesium methoxide, magnesium ethoxide, magnesium n-propoxide, magnesium i-propoxide, magnesium n-butoxide, magnesium sec-butoxide or magnesium tert-butoxide. The side powder or an alcohol solution thereof can be prepared by reacting with 2-methoxyethanol to exchange an alcohol (alkoxide) reaction (i.e., dialcohol decomposition reaction).

The alcohol solution of barium alkoxide is directly added to the barium metal chip, for example, by adding methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol in small portions. Barium methoxide, barium ethoxide, barium n-propoxide, barium i-propoxide, barium n-butoxide, barium sec-butoxide, barium tert-butoxide or barium 2 prepared by reacting metal with alcohol -Methoxyethoxide alcohol solution can be used. It is also possible to convert the barium alkoxide to another barium alkoxide for use. For example, barium methoxyethoxide solution may be barium methoxide, barium ethoxide, barium n-propoxide, barium i-propoxide, barium n-butoxide, barium sec-butoxide or barium tert-butoxide. It can manufacture by reacting side powder or its alcohol solution with 2-methoxyethanol, and degrading the alcohol.

As the alcohol solution of the aluminum alkoxide, the catalyst is added to the aluminum metal chip by adding methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol in small portions. Aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum i-propoxide, aluminum n-butoxide, aluminum sec-butoxide, aluminum tert-butoxide prepared by directly reacting metal with alcohol Said or aluminum methoxyethoxide alcohol solution may be used. It is also possible to convert aluminum alkoxides to other aluminum alkoxides for use. For example, the aluminum methoxyethoxide solution may be aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum i-propoxide, aluminum n-butoxide, aluminum sec-butoxide or aluminum tert-butoxide. It can manufacture by reacting side powder or its alcohol solution with 2-methoxyethanol, and degrading the alcohol.

Examples of alcohol solutions of silicon alkoxides include tetraalkylorthosilicate (Si (OR) ₄ ) alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2 Silicon methoxide, silicon ethoxide, silicon n-propoxide, silicon i-propoxide, silicon n-butoxide, silicon sec-butoxide, silicon tert-butoxide prepared by addition of methoxyethanol Or silicon methoxyethoxide alcohol solution.

As an alcohol solution of calcium alkoxide, alcohol, such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol, is added to the calcium metal chip little by little. Calcium methoxide, calcium ethoxide, calcium n-propoxide, calcium i-propoxide, calcium n-butoxide, calcium sec-butoxide, calcium tert-butoxide or calcium prepared by direct metal reaction with alcohol Methoxyethoxide alcohol solution can be used. It is also possible to convert calcium alkoxides to other calcium alkoxides. For example, the calcium methoxyethoxide solution may be calcium methoxide, calcium ethoxide, calcium n-propoxide, calcium i-propoxide, calcium n-butoxide, calcium sec-butoxide or calcium tert-butoxide. It may also be prepared by reacting a side powder or an alcohol solution thereof with 2-methoxyethanol.

As an alcohol solution of strontium alkoxide, alcohol, such as methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert-butanol or 2-methoxyethanol, is added to the strontium metal chip little by little. Strontium methoxide, strontium ethoxide, strontium n-propoxide, strontium i-propoxide, strontium n-butoxide, strontium sec-butoxide, strontium tert-butoxide or strontium prepared by directly reacting metal with alcohol Methoxyethoxide alcohol solution can be used. In addition, strontium alkoxide can also be used by converting into another strontium alkoxide. For example, the strontium methoxyethoxide solution may be strontium methoxide, strontium ethoxide, strontium n-propoxide, strontium i-propoxide, strontium n-butoxide, strontium sec-butoxide or strontium tert-butoxide. It can manufacture by reacting side powder or its alcohol solution with 2-methoxyethanol, and degrading the alcohol.

In the process of the invention, the alcohols used in the first and second solutions may be the same or different, for example methanol, ethanol, n-propanol, i-propanol, n-butanol, sec-butanol, tert- Butanol or 2-methoxyethanol.

In the embodiment of the present invention, an oxide is coated on the iron-based amorphous magnetic alloy thin ribbon using the coating apparatus of FIG. 1. The bobbin 3 is attached to the bobbin 1 of FIG. 1, and is connected to the bobbin 7 via several pulleys 2. The thin ribbon in the bobbin 1 is moved at a constant speed by the rotation of the bobbin 7. The coating solution 4 is allowed to adsorb to the surface of the ribbon by passing the ribbon 3 through the coating solution 4 placed in the coating chamber 5 under an inert gas atmosphere (eg, argon or nitrogen atmosphere). The thin ribbon of the coating solution adsorbed and coated uniformly is dried.

Hereinafter, the present invention will be described in detail in the Examples. In the specification, including examples, alcohols generally described or alcohols described by specific names (eg, ethanol, etc.) refer to anhydrous alcohols unless stated otherwise.

<Example 1>

Magnesium ethoxide was prepared by putting magnesium ethoxide [Mg (OCH ₂ CH ₃ ) ₂ powder in an excess of 2-methoxyethanol [CH ₃ OCH ₂ CH ₂ OH] and refluxing in an argon gas atmosphere. Excess ethanol present in the solution was removed using a vacuum trap, and 2-methoxyethanol was added again in a glove box to make the solution exactly 0.5 M (first solution). Then 0.5M aqueous ethanol solution was prepared (second solution). The same volume of the first solution and the second solution were slowly combined, taking care not to precipitate, resulting in a final coating solution.

Subsequently, the prepared coating solution was used to form an oxide film using the coating apparatus shown in FIG. Metglas 2605S3A (composition Fe _76.5 Cr ₂ B ₁₆ Si ₅ C _0.5 ) (3) was attached to the bobbin (1) of FIG. 1, and then connected to the bobbin (7) via several pulleys (2) made of Teflon. . The thin ribbon in the bobbin 1 is moved at a constant speed by the rotation of the bobbin 7. The coating solution was adsorbed and coated on the surface of the ribbon by passing the ribbon through the coating solution 4 placed in the coating chamber 5 under argon atmosphere. The thin ribbon of the coating solution uniformly adsorbed and coated on the surface was dried by passing an induction-winding electric furnace 6 so as not to generate a magnetic field. The temperature of the electric furnace was 200 degreeC.

The thickness of the coated oxide film was measured using a digital micrometer. In order to improve the accuracy of the measurement, the thickness of the coated oxide film was calculated by stacking thin ribbons in 10 to 20 layers and then measuring the total thickness of the laminate, and dividing it by the number of laminated ribbons. The thickness of the MgO film measured was 0.7 μm.

Oxide-coated thin ribbon was wound to 50 layers of aluminum bobbins with an inner diameter of 19 mm, and heat treated at 435 ° C. for 2 hours using a coiled electric furnace so that the heating wire did not generate a magnetic field under a nitrogen atmosphere. Investigate. As a magnetic property, the change of the effective permeability according to frequency was measured as the direct current hysteresis curve and the alternating current property with respect to the sample which did not form an oxide film and the sample which formed the oxide film by the said method.

The hysteresis curve was measured using a magnetic hysteresis measuring apparatus (Model TRF-5AH1 manufactured by Toei, Japan). The hysteresis curve of the sample which did not form an oxide film is shown in FIG. 2, and the hysteresis curve of the sample in which the MgO film which concerns on this invention was formed is shown in FIG. As can be seen from the results of FIGS. 2 and 3, the square ratio of the sample without forming the oxide film was 0.40, and the square ratio of the sample with the MgO coating according to the present invention was 0.74.

Effective permeability was measured in a magnetic field of 10 mOe using an impedance analyzer (Model 4219A, manufactured by Hewlett Packard). The results are shown in FIG. As can be seen in Figure 12, the effective permeability of the sample formed MgO film according to the present invention showed a higher effective permeability than the sample without the oxide film formed at a frequency of less than 100 kHz, but showed a similar value at high frequencies .

<Example 2>

Except that the final coating solution was prepared using a 0.5 M barium methoxyethoxide solution synthesized by directly reacting the metal with alcohol while gradually adding 2-methoxyethanol to the barium metal chip as the first solution. An oxide film was coated in the same manner as in Example 1. The oxide formed at this time was BaO, and the thickness of the oxide film was 0.4 µm.

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

As can be seen from the results of FIG. 2 and FIG. 4, the square ratio of the sample in which the oxide film was formed according to the present invention was greatly reduced. Specifically, the square ratio of the sample in which the oxide film was not formed was 0.4. Therefore, the square ratio of the sample in which the BaO film was formed was 0.20.

As can be seen in Figure 12, the effective permeability of the sample formed BaO film according to the present invention shows a smaller value in the frequency range of 400 kHz or less than the sample without the oxide film, but the decrease in effective permeability with frequency is very small Nearly constant effective permeability values were observed up to the frequency of 100 kHz.

<Example 3>

A 0.5 M aluminum methoxyethoxide solution was prepared by adding 2-methoxyethanol to aluminum isopropoxide {A1 [OCH (CH ₃ ) ₂ ] ₃ } as a first solution and refluxing at a temperature of 85 ° C. for 90 minutes. In the same manner as in Example 1, except that a final coating solution was prepared using ethanol to which water was not added as a second solution. The oxide formed at this time was Al ₂ O ₃ , and the thickness of the oxide film was 0.39 μm.

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

As can be seen in Figures 2 and 5, the square ratio of the sample forming the oxide film according to the present invention was somewhat reduced, specifically, the square ratio of the sample without forming the oxide film is 0.40, but according to the present invention squareness of the sample was formed an Al ₂ O ₃ film was 0.34.

As can be seen in FIG. 12, the effective permeability of the sample in which the Al ₂ O ₃ film was formed according to the present invention was higher in the entire frequency range than the sample in which the oxide film was not formed.

<Example 4>

A solution of 5.0 g (6.330 ml) of ethanol, 4.325 g of water and 0.3 ml of hydrochloric acid was slowly added to 12.50 g of TEOS (tetraethyl orthosilicate) solution diluted with 6.06 g (7.67 ml) of ethanol. An oxide film was coated on the amorphous magnetic alloy thin ribbon as in Example 1 except that the coating solution was prepared by stirring for 40 minutes while maintaining the temperature at 占 폚. The oxide formed at this time was SiO ₂ , and the thickness of the oxide film was 0.65 μm.

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

As can be seen in Figures 2 and 6, the square ratio of the sample in which the oxide film was formed according to the present invention was increased. Specifically, the square ratio of the sample in which the oxide film was not formed was 0.40. The square ratio of the sample which formed ₂ film was 0.57.

As can be seen in FIG. 12, the effective permeability of the sample in which the SiO ₂ film was formed according to the present invention was lower in the entire frequency range than the sample in which the oxide film was not formed.

Example 5

The first solution was prepared by mixing the magnesium methoxyethoxide solution prepared in Example 1 and the aluminum methoxyethoxide solution prepared in Example 3 in the same molar number and refluxing, and water was not added as the second solution. An oxide film was coated in the same manner as in Example 1 except that the coating solution was prepared using ethanol. The oxide formed at this time was MgO-Al ₂ O ₃ , and the thickness of the oxide film was 0.75 μm.

The hysteresis curve and the effective 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 of FIG. 2 and FIG. 7, the square ratio of the sample in which the MgO.Al ₂ O ₃ film was formed according to the present invention was greatly increased. Specifically, the square ratio of the sample without forming the oxide film was increased. 0.40 and was squareness of the sample was formed an Al ₂ O ₃ film according · MgO to the present invention is 0.71.

As can be seen in FIG. 13, the effective permeability of the sample in which the oxide film was formed according to the present invention was higher in the entire frequency range than the sample in which the oxide film was not formed.

<Example 6>

2-methoxyethanol was added to the calcium methoxide [Ca (OCH ₃ ) ₂ ] to reflux to prepare a calcium methoxy ethoxide solution of 0.5 M, followed by the aluminum methoxy ethoxide solution prepared in Example 3. Was mixed in the same molar number and refluxed to prepare a first solution, and an oxide film was coated in the same manner as in Example 1 except that a coating solution was prepared using ethanol to which water was not added as a second solution. The oxide formed at this time was CaO · Al ₂ O ₃ , and the thickness of the oxide film was 1.92 μm.

The hysteresis curve and the effective permeability were measured in the same manner as in Example 1. The results are shown in FIGS. 8 and 13, respectively.

As can be seen from the results of FIG. 2 and FIG. 8, the square ratio of the sample in which the CaO · Al ₂ O ₃ film was formed was somewhat reduced according to the present invention. Specifically, the square ratio of the sample in which the oxide film was not formed was 0.40 and was squareness of the sample was formed an Al ₂ O ₃ film according · CaO with the present invention is 0.34.

As can be seen from FIG. 13, the effective permeability of the sample having the CaO · Al ₂ O ₃ film formed according to the present invention was lower at a frequency of about 300 kHz or less than that of the sample without the oxide film, but was higher at higher frequencies.

<Example 7>

0.5M strontium methoxyethoxide solution synthesized by directly reacting metal and alcohol with the addition of 2-methoxyethanol little by little to the strontium metal chip with the same number of moles of aluminum methoxyethoxide solution prepared in Example 3 The first solution was prepared by mixing and refluxing, and the oxide film was coated in the same manner as in Example 1 except that the final coating solution was prepared using ethanol without adding water as the second solution. The oxide formed at this time was SrO-Al ₂ O ₃ , and the thickness of the oxide film was 1.68 μm.

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

As can be seen from the results of FIG. 2 and FIG. 9, the square ratio of the sample in which the SrO.Al ₂ O ₃ film was formed was greatly reduced according to the present invention. Specifically, the square ratio of the sample without the oxide film was formed. Was 0.40, but the square ratio of the sample in which the SrO-Al ₂ O ₃ film was formed in accordance with the present invention was 0.16.

As can be seen in Figure 13, the effective permeability of the sample formed with the SrO-Al ₂ O ₃ film according to the present invention shows a smaller value in the frequency range of 600 kHz or less than the sample without the oxide film is formed, but the effective permeability decreases with frequency. Is very small, showing a nearly constant effective permeability value up to a frequency of 100 kHz.

<Example 8>

The first solution was prepared by mixing the barium methoxyethoxide solution prepared in Example 2 and the aluminum methoxyethoxide solution prepared in Example 3 in the same molar number and refluxing, and no water was added as the second solution. An oxide film was coated in the same manner as in Example 1 except that the coating solution was prepared using ethanol. The oxide formed at this time was BaO · Al ₂ O ₃ , and the thickness of the oxide film was 1.80 μm.

The hysteresis curve and the effective permeability were measured in the same manner as in Example 1. The results are shown in FIGS. 10 and 13, respectively.

As can be seen from the results of FIG. 2 and FIG. 10, the square ratio of the sample on which the BaO · Al ₂ O ₃ film was formed was greatly reduced according to the present invention. However, the square ratio of the sample in which the BaO-Al ₂ O ₃ film was formed in accordance with the present invention was 0.17.

As can be seen in Figure 13, the effective permeability of the sample formed BaO · Al ₂ O ₃ film according to the present invention shows a smaller value in the frequency range of 700 kHz or less than the sample without the oxide film, the effective permeability according to frequency The decrease in is very small, showing an almost constant effective permeability value up to a frequency of 100 kHz.

Example 9

Tetraethyl orthosilicate (TEOS) is mixed with 2-methoxyethanol and refluxed to prepare a 0.5M silicon methoxyethoxide solution and the magnesium methoxyethoxide solution prepared in Example 1 in the same molar number and then refluxed. The oxide film was coated in the same manner as in Example 1 except that a first solution was prepared and a coating solution was prepared using ethanol to which water was not added as a second solution. The oxide formed at this time was MgO.SiO ₂ , and the thickness of the oxide film was 1.39 μm.

The hysteresis curve and the effective permeability were measured in the same manner as in Example 1. The results are shown in FIGS. 11 and 13, respectively.

As can be seen from the results of FIG. 2 and FIG. 11, according to the present invention, the angular ratio of the sample in which the MgO.SiO ₂ film was formed increased slightly. Specifically, the angular ratio of the sample in which the oxide film was not formed was 0.40. The square ratio of the sample in which the MgO.SiO ₂ film was formed according to the present invention was 0.50.

As can be seen in FIG. 13, the effective permeability of the sample with MgO.SiO ₂ film formed according to the present invention was lower at frequencies below about 100 kHz but higher at frequencies higher than the sample without oxide film.

By adjusting the type of the oxide film, it is possible to control the induced magnetic anisotropy of the iron-based amorphous magnetic alloy thin ribbon over a wide range, and therefore, it is possible to control the magnetic properties over a wide range.

Claims (4)

MgO, Al ₂ O ₃ , SiO ₂ , BaO, MgO-Al ₂ O ₃ , MgO-SiO ₂ , CaO-Al ₂ O ₃ , BaO-Al ₂ O ₃ and SrO-Al ₂ O ₃ Preparing a sol-gel solution of the oxide, Coating the sol-gel solution on the surface of an iron-based amorphous magnetic alloy thin ribbon, Drying the coated iron-based amorphous magnetic alloy thin ribbon, and Heat-treating the dried coated iron-based amorphous magnetic alloy thin ribbon A method of forming induction magnetic anisotropy in an iron-based amorphous magnetic alloy thin ribbon, characterized in that consisting of. The sol-gel solution of MgO, SiO ₂ or BaO, according to claim 1, prepares an alcohol solution of an alkoxide corresponding to the desired oxide and adds the solution to an alcohol containing an equimolar amount of water with the alkoxide contained therein. A method of forming induction magnetic anisotropy in an iron-based amorphous magnetic alloy thin ribbon produced by mixing by mixing. The iron-based amorphous compound according to claim 1, wherein the sol-gel solution of Al ₂ O ₃ is prepared by preparing an alcohol solution of an alkoxide corresponding to the desired oxide, and adding this solution to an alcohol containing no water. Method of forming induced magnetic anisotropy in magnetic alloy thin ribbons. According to claim _{1, MgO · Al 2 O 3,} MgO · SiO 2, CaO · Al 2 O 3, BaO · Al 2 O 3 or sol of SrO · Al ₂ O ₃ - gel solution is the purpose, each of the double oxide It is prepared by dissolving two kinds of alkoxides corresponding to the components of in the same alcohol to prepare two kinds of alcohol solution, mixing the two solutions, and adding the mixture to an alcohol containing no water to react. A method of forming induced magnetic anisotropy in amorphous magnetic alloy thin ribbons.