Insulating coating composition for electrical steel sheet, electrical steel sheet, and method for manufacturing same

Abstract

An insulating coating for an electrical steel sheet, according to an embodiment of the present invention, comprises: 100 parts by weight of silica; 10 to 500 parts by weight of metal hydrofluoric acid; and 50 to 500 parts by weight of at least one shielding agent among dolomite, talc, carbonate, and feldspar.

Description

Electrical steel sheet insulation film composition, electrical steel sheet, and method of manufacturing the same

[0001] One embodiment of the present invention relates to an electrical steel sheet insulating film composition, an electrical steel sheet, and a method for manufacturing the same. Specifically, by appropriately combining the components of the insulating film composition, the invention relates to an electrical steel sheet insulating film composition, an electrical steel sheet, and a method for manufacturing the same, which exhibits excellent durability and extreme corrosion resistance in high-temperature and high-humidity environments, as well as excellent heat resistance at very high temperatures such as stress relief annealing (SRA).

[0002] Electrical steel sheets are products used as materials for transformers, motors, and electrical equipment. Unlike general carbon steel, which prioritizes processability such as mechanical properties, electrical steel is a functional product that places importance on electrical characteristics. Required electrical properties include low iron loss and high magnetic flux density, permeability, and stacking density.

[0003] Electrical steel sheets are further classified into oriented electrical steel sheets and non-oriented electrical steel sheets. Oriented electrical steel sheets utilize an abnormal grain growth phenomenon called secondary recrystallization to form a Goss texture ({110} <001> It is an electrical steel sheet with excellent magnetic properties in the rolling direction, formed by creating a texture throughout the entire sheet. Non-oriented electrical steel is an electrical steel sheet in which magnetic properties are uniform in all directions on the rolled sheet.

[0004] Meanwhile, the formation of an insulating film is a process corresponding to the final manufacturing process of a product. In addition to electrical properties that suppress the generation of eddy currents, it typically requires continuous stamping processability to suppress mold wear when multiple sheets are stacked to form a core after stamping into a predetermined shape, as well as anti-sticking properties and surface adhesion to prevent adhesion between core sheets after the SRA process, which removes processing stress from the steel sheets and restores magnetic properties. In addition to these basic properties, excellent application workability of the coating solution and solution stability that allows for long-term use after mixing are also required. Coating solutions used for this purpose include chromium coatings based on chromic acid and phosphate coatings based on phosphate.

[0005] These coatings have the disadvantage of having inferior corrosion resistance. In addition, it is known that various solution properties are inferior when chromium is not added. Therefore, we intend to develop an environmentally friendly insulating coating with relatively excellent corrosion resistance.

[0006] In one embodiment of the present invention, an electrical steel sheet insulating film composition, an electrical steel sheet, and a method for manufacturing the same are provided. Specifically, by appropriately combining the components of the insulating film composition, the present invention aims to provide an electrical steel sheet insulating film composition, an electrical steel sheet, and a method for manufacturing the same, which exhibit excellent durability and extreme corrosion resistance in high-temperature and high-humidity environments, as well as excellent heat resistance at very high temperatures such as stress relief annealing (SRA).

[0007] An insulating film composition for electrical steel sheets according to one embodiment of the present invention comprises 100 parts by weight of silica, 10 to 500 parts by weight of metallic hydrofluoric acid, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

[0008] An insulating film composition for electrical steel sheets according to one embodiment of the present invention may further include 10 to 100 parts by weight of pigment.

[0009] The pigment may include one or more oxides of Mn, Fe, and Cu.

[0010] Silica can have a pH of 8 to 12.

[0011] Metallic hydrofluoric acid may include one or more of fluorinated titanoic acid (F6H2Ti) and fluorinated zirconic acid (F6H2Zr).

[0012] An electrical steel sheet according to one embodiment of the present invention comprises an electrical steel sheet substrate and an insulating film located on the surface of the electrical steel sheet substrate, and

[0013] The insulating film may comprise 100 parts by weight of silica, 10 to 500 parts by weight of a complex metal oxide, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

[0014] The complex metal oxide may contain Zr and Ti.

[0015] A method for manufacturing an electrical steel sheet according to one embodiment of the present invention comprises the steps of: preparing an electrical steel sheet substrate; applying an insulating film composition to the surface of the electrical steel sheet substrate; and heat-treating the electrical steel sheet substrate, wherein the insulating film composition comprises 100 parts by weight of silica, 10 to 500 parts by weight of hydrofluoric acid, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

[0016] The heat treatment step can be performed at a temperature of 750 to 1000°C for 10 to 300 seconds.

[0017] According to one embodiment of the present invention, it has excellent durability and extreme corrosion resistance in high-temperature and high-humidity environments, and excellent heat resistance at very high processability temperatures such as stress relief annealing (SRA).

[0018] According to one embodiment of the present invention, it has a very excellent insulation effect in a high-frequency magnetic field environment.

[0019] FIG. 1 is a schematic diagram of a cross-section of an electrical steel sheet according to one embodiment of the present invention.

[0020] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0021] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0022] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other part is interposed in between.

[0023] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0025]

[0026] According to one embodiment of the present invention, the insulating film for electrical steel sheets comprises 100 parts by weight of silica, 10 to 500 parts by weight of metallic hydrofluoric acid, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

[0027] Each component is described in detail below. In one embodiment of the present invention, the weight part refers to a relative weight ratio based on 100 weight parts of silica, and is based on the solid content of each component. Solid content refers to the weight when each component is dried in a state free of volatile substances such as solvents. Specifically, assuming a heat treatment process when forming an insulating film, it refers to the weight remaining after heat treatment.

[0028]

[0029] Silica is a necessary component for reducing iron loss by imparting tension to steel plates. If too little silica is included, it is difficult to obtain a sufficient tension-imparting effect on the steel plates. If too much silica is included, problems may arise regarding stickiness or solution stability.

[0030] Silica may include basic and acidic properties, and more specifically, may include basic properties. When basic silica is included, it is advantageous in terms of the stability of the insulating film composition, and the storage stability of the solution may be improved. The basic silica may have a pH of 8 to 12. The silica can be dispersed in a sol form to measure the pH.

[0031] The silica may have an average particle size in the range of 5 to 20 nm. If the average particle size of the silica is too small, the condensation reaction rate is fast, causing aggregation and potentially inducing color deviation defects on the surface. If the average particle size is too large, the surface area per unit mass decreases, slowing down the condensation reaction rate and potentially causing defects. More specifically, the silica may have an average particle size in the range of 10 to 15 nm. In one embodiment of the present invention, the particle size can be measured using a particle size meter called Zeta Potential, and the average particle size is the arithmetic mean.

[0032] Silica may be composed of at least one nanoparticle having a different average particle size. Specifically, the silica may be used by mixing at least one silica nanoparticle having a different average particle size to form an insulating film having excellent film properties.

[0033] An insulating film composition for electrical steel sheets according to one embodiment of the present invention comprises 10 to 500 parts by weight of metallic hydrofluoric acid per 100 parts by weight of silica. In the case of conventional insulating film compositions, oxide particles such as TiO2, ZrO2, and MnO2 were included as inorganic ceramic particles. However, in this case, the solution gels, which poses a problem in terms of solution stability. On the other hand, when added to the insulating film composition in the form of metallic hydrofluoric acid as in one embodiment of the present invention, it does not gel and offers excellent solution stability. Meanwhile, during the process of forming the insulating film, the metallic hydrofluoric acid reacts during the coating formation heat treatment process and changes into an insoluble substance. That is, when present in the insulating film composition in the form of metallic hydrofluoric acid, the viscosity of the solution is maintained close to the Newtonian fluid characteristics for application to a natural coater. Specifically, the viscosity of the insulating film composition can be maintained at 10 cp or less. More specifically, the viscosity can be 1 to 10 c.p. At this time, viscosity can be measured at a temperature of 30℃ using a Brook Field viscometer.

[0034] If too little metallic hydrofluoric acid is included, problems may arise regarding corrosion resistance and weather resistance. If too much metallic hydrofluoric acid is included, gelation may occur, which may cause problems in terms of solution stability. More specifically, the metallic hydrofluoric acid may be included in an amount of 30 to 300 parts by weight. More specifically, it may be included in an amount of 50 to 200 parts by weight.

[0035] The metallic hydrofluoric acid may include one or more of fluorinated titanic acid (F6H2Ti) and fluorinated zirconic acid (F6H2Zr). More specifically, it may include fluorinated titanic acid (F6H2Ti) and fluorinated zirconic acid (F6H2Zr) simultaneously. When fluorinated titanic acid (F6H2Ti) and fluorinated zirconic acid (F6H2Zr) are included simultaneously, it may include 10 to 300 parts by weight of fluorinated titanic acid (F6H2Ti) and 10 to 300 parts by weight of fluorinated zirconic acid (F6H2Zr). More specifically, it may include 20 to 150 parts by weight of fluorinated titanic acid (F6H2Ti) and 20 to 150 parts by weight of fluorinated zirconic acid (F6H2Zr).

[0036]

[0037] An insulating film composition for electrical steel sheets according to one embodiment of the present invention comprises 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar, based on 100 parts by weight of silica.

[0038] In one embodiment of the present invention, the shielding agent plays a role in improving insulation in an ultra-high frequency environment and, in addition, also exhibits the effect of making the surface color uniform. In one embodiment of the present invention, the ultra-high frequency environment refers to a band below 200 GHz, and if the insulation is excellent, when applied to oriented electrical steel sheets, it helps improve the electromagnetic shielding function at 50 to 70 Hz, or more narrowly at 60 Hz, around facilities near transmission towers or high-voltage power lines. If too little of the shielding agent is included, the aforementioned role cannot be properly performed. If too much of the shielding agent is added, the lifespan of the solution may be shortened. More specifically, the shielding agent may be included in an amount of 65 to 300 parts by weight. More specifically, the shielding agent may be included in an amount of 75 to 250 parts by weight.

[0039] The shielding agent may include one or more of dolomite, talc, carbonate, and feldspar. These materials are known to be applied in the cosmetics, paint, and ceramics industries. Additionally, they provide surface roughness and play a role in uniformizing surface color differences by scattering and blocking light through their crystal structure. However, these materials have the problem of being difficult to apply uniformly without using organic polymers or organic dispersants. In one embodiment of the present invention, the aforementioned metal hydrofluoric acid is added together to enable the shielding agent to be applied uniformly.

[0040] Dolomite, also known as paleofossil, is chemically represented as CaMg(CO3)2. Talc (talcum) is a magnesium-containing silicate mineral, H2Mg3(SiO3)4 or Mg3Si4O 10 It is represented as (OH)2. Carbonates are carbonate ions CO3 2- It is a salt of carbonate present therein. Specifically, it may include one or more of magnesium carbonate, barium carbonate, and calcium carbonate. The feldspar is a network-structured silicate mineral, and more specifically, may include albite (soda feldspar) and orthoclase (potassium feldspar). More specifically, as a shielding agent, it may include talc.

[0041] Meanwhile, in one embodiment of the present invention, the color may differ from existing products due to the addition of a shielding agent, and a pigment may be added to compensate for this. The pigment may be added in an amount of 10 to 100 parts by weight per 100 parts by weight of silica. More specifically, it may be included in an amount of 25 to 75 parts by weight.

[0042] The pigment is not particularly limited but may include one or more oxides of Mn, Fe, and Cu. More specifically, it may include oxides of Mn, oxides of Fe, and oxides of Cu.

[0043] In addition to the aforementioned components, the composition for forming an insulating film may further include a solvent. The solvent serves to facilitate the application of the composition and to uniformly disperse the components. The amount of solvent is not particularly limited, but may be included in an amount of 100 to 1,000 parts by weight per 100 parts by weight of silica.

[0044] In one embodiment of the present invention, metal phosphates and chromic acid may not be included. If metal phosphates are included in the insulating film composition, the weather resistance becomes very poor. Since chromic acid has a fatal effect on the environment, it may not be included. More specifically, metal phosphates and chromic acid are included in an amount of 1 part by weight or less per 100 parts by weight of silica.

[0045]

[0046] FIG. 1 shows a schematic cross-sectional view of an electrical steel sheet (100) according to one embodiment of the present invention. As shown in FIG. 1, the electrical steel sheet (100) according to one embodiment of the present invention includes an electrical steel sheet substrate (10) and an insulating film (20) located on the electrical steel sheet substrate (10).

[0047] The electrical steel substrate (10) can be any general non-oriented or oriented electrical steel without limitation. In one embodiment of the present invention, since the main configuration is to form an insulating film (20) of a special component on the electrical steel substrate (10), a detailed description of the electrical steel substrate (10) is omitted.

[0048] Additionally, the composition of the grain-oriented electrical steel substrate is explained as follows.

[0049] The oriented electrical steel substrate comprises silicon (Si): 2.0 to 7.0 wt%, aluminum (Al): 0.020 to 0.040 wt%, manganese (Mn): 0.01 to 0.20 wt%, phosphorus (P) 0.01 to 0.15 wt%, carbon (C) 0.01 wt% or less (excluding 0%), N: 0.005 to 0.05 wt%, and antimony (Sb), tin (Sn), or a combination thereof 0.01 to 0.15 wt%, and the remainder may comprise Fe and other unavoidable impurities. Since the description of each component of the oriented electrical steel substrate (10) is the same as generally known, a detailed description is omitted.

[0050] Between the grain-oriented electrical steel substrate and the insulating film, a metal oxide layer (base coating layer, primary film) formed by reacting with an annealing separator and the oxide layer of the steel sheet during the secondary recrystallization process may exist. An example of the metal oxide layer may be a forsterite layer. It is also possible to suppress the formation of the metal oxide layer or remove the metal oxide layer during the manufacturing process of the grain-oriented electrical steel so that the grain-oriented electrical steel substrate and the insulating film come into contact.

[0051] The thickness of the insulating film (20) can be 0.5 to 10 μm. If the thickness of the insulating film (20) is too thin, it is difficult to secure adequate insulation. If the thickness of the insulating film (20) is too thick, the packing density may be reduced. In one embodiment of the present invention, adequate insulation can be secured even when forming an insulating film (20) of thin thickness. More specifically, the thickness of the insulating film (20) can be 1 to 5 μm.

[0052] The insulating film (20) comprises a composite metal oxide containing two or more types of metals. This composite metal oxide is formed as metal hydrofluoric acid reacts within the insulating film composition during the process of forming the insulating film. When added in the form of metal oxides as in conventional insulating film compositions, the reaction between the metal oxides does not occur, and the composite metal oxide is not formed.

[0053] Since the complex metal oxide is derived from metallic hydrofluoric acid, it may contain metals present in the metallic hydrofluoric acid. More specifically, it may contain Zr and Ti.

[0054] The complex metal oxide in the insulating film originates from the metal hydrofluoric acid in the insulating film composition, and since they all react to form the complex metal oxide, the complex metal oxide in the insulating film may be included in an amount of 10 to 500 parts by weight per 100 parts by weight of silica. As the content of the complex metal oxide has already been explained in relation to the metal hydrofluoric acid in the insulating film composition, a redundant explanation is omitted.

[0055] The insulating film (20) may comprise 100 parts by weight of silica, 10 to 500 parts by weight of a composite metal oxide, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar. Except for the composite metal oxide and the metal hydrofluoric acid, the insulating film may be substantially the same as the solid components in the aforementioned insulating film composition.

[0056]

[0057] A method for manufacturing an electrical steel sheet according to one embodiment of the present invention comprises the steps of: preparing an electrical steel sheet substrate; applying an insulating film composition to the surface of the electrical steel sheet substrate; and performing heat treatment.

[0058] As detailed information regarding the electrical steel substrate and the insulating film composition has been provided previously, redundant explanations will be omitted.

[0059] For example, the substrate of an electrical steel sheet can be manufactured as follows.

[0060] A steel slab is prepared. In the next step, the steel slab is heated. At this time, the slab may be heated using the low-temperature slab method at 1,200°C or lower. Next, the heated steel slab is hot-rolled to produce a hot-rolled plate. Subsequently, the produced hot-rolled plate may be hot-rolled and annealed. Next, the hot-rolled plate is cold-rolled to produce a cold-rolled plate. Cold rolling may be performed once, or two or more cold-rolling steps including intermediate annealing may be performed. Next, the cold-rolled plate is subjected to primary recrystallization annealing. At this time, the step of primary recrystallizing annealing of the cold-rolled plate may include a step of simultaneously decarburizing and nitriding the cold-rolled plate, or a step of nitriding annealing after decarburizing annealing. Next, an annealing separating agent is applied to the surface of the recrystallized steel plate. The application amount of the annealing separating agent is 1 to 5 g / m² 2 If the amount of annealing separator applied is too small, film formation may not proceed smoothly. If the amount of annealing separator applied is too large, it may affect secondary recrystallization. Therefore, the amount of annealing separator applied can be controlled within the aforementioned range. Next, the steel plate coated with the annealing separator is subjected to secondary recrystallization annealing. During secondary recrystallization annealing, the primary cracking temperature can be set to 650 to 750 ℃, and the secondary cracking temperature to 1100 to 1250 ℃. The temperature range of the heating section can be controlled at a condition of 15 ℃ / hr. In addition, the gas atmosphere can be performed in an atmosphere containing 20 to 30 volume% nitrogen and 70 to 80 volume% hydrogen up to the primary cracking stage, and in the secondary cracking stage, it can be maintained in a 100% hydrogen atmosphere for 15 hours and then furnace cooling.

[0061] In the heat treatment step, the heat treatment temperature may be 700 to 1000°C. If the temperature is too low, the time required to form the insulating film may be too long, which may result in poor continuous processing performance. If the temperature is too high, heat resistance and bluening resistance may be reduced due to cracking. More specifically, the heat treatment temperature may be 750 to 950°C. More specifically, it may be 750 to 900°C. The heat treatment time may be 10 to 300 seconds. More specifically, it may be 30 to 180 seconds.

[0062] The atmosphere during heat treatment may be a nitrogen atmosphere.

[0063]

[0064] Preferred embodiments of the present invention, comparative examples, and evaluation examples thereof are described below. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0065]

[0066] Examples

[0067] A oriented electrical steel sheet (300*60mm) containing 3.1% Si by weight and having a primary film finished annealed with a thickness of 0.23mm was prepared as a test material.

[0068] An insulating film composition was prepared by mixing the components in the ratios summarized in Table 1 below. First, basic colloidal silica (average particle size 15 nm, pH 10) was added to water and mixed. Subsequently, metallic hydrofluoric acid, a shielding agent (talc), and pigments were added to finally prepare the insulating film composition. As pigments, Fe2O3, CuO, and MnO were added in a weight ratio of 1:2:1.

[0069] Apply the prepared solution to both sides of the electrical steel sheet at 3.1 g / mm 2 An insulating film with a thickness of 1 μm was formed by applying and heat treating at 850°C for 45 seconds.

[0070] Weather resistance, corrosion resistance, solution stability, and adhesion were evaluated using the following methods and summarized in Table 2.

[0071]

[0072] Weather resistance evaluation

[0073] Weather resistance was evaluated under conditions of 98% moisture, 60°C, and 72 hours, and was marked as “OK” if good and “NG” if poor.

[0074]

[0075] Corrosion resistance evaluation

[0076] A salt spray test was conducted at 5% NaCl, 100 RH, 65 ℃, for 8 hours. It was marked “OK” if good and “NG” if poor.

[0077]

[0078] Solution stability evaluation

[0079] After storing the solution at 30℃ for 72 hours, it was measured using a Brook Field viscometer.

[0080]

[0081] Adhesion strength evaluation

[0082] For the adhesion evaluation, heating was performed for 2 hours under conditions of 560 ℃, 20% hydrogen, and 80% nitrogen. Subsequently, the adhesion was evaluated through a CROSS-HATCH CUT test.

[0083] If the result of the above test is 5B or higher, it is indicated as “OK” as good, and if it is less than 5B, it is indicated as “NG” as poor.

[0084]

[0085] Classification (parts by weight) Silica H2F6 Zr H2F6 Ti Talc Pigment 1 100 75 75 100 50 2 100 50 100 100 50 3 100 20 130 100 50 4 100 130 20 100 50 5 100 100 50 100 50 6 100 600 100 50 7 100 600 100 50 8 100 75 75 20 50 9 100 75 75 600 50 10 100 75 75 600 10 11 100 (Acidic) 75 75 100 50 12 100 75 (ZrO2) 75 (TiO2) 100 50

[0086] Classification Weathering Resistance Corrosion Resistance Solution Stability Adhesion 1 OK OK 3 OK Example 2 OK OK 3 OK Example 3 OK OK 3 OK Example 4 OK OK 3 OK Example 5 OK OK 3 OK Example 6 OK NG 3 NG Comparative Example 7 OK NG 3 OK Comparative Example 8 OK NG 3 OK Comparative Example 9 OK OK 6 0 OK Comparative Example 10 OK OK 7 0 OK Comparative Example 11 OK NG 19 OK Comparative Example 12 NG NG 13 NG Comparative Example

[0087] As shown in Tables 1 and 2, when the components of the insulating film composition are included in an appropriate amount, it can be confirmed that weather resistance, corrosion resistance, solution stability, and adhesion are all excellent simultaneously. On the other hand, when the components of the insulating film composition are not included in an appropriate amount, it can be confirmed that some properties are inferior. Meanwhile, XRD analysis was performed on Specimen 1 to obtain the values ​​shown in Table 3 below. Through this, it was confirmed that the amount of composite metal oxide in the insulating film is 10 parts by weight.

[0088] Element Binding Energy (eV) Strength Ti4594400Zr182800Ti-Zr3502200

[0089] Meanwhile, analysis was performed on Sample 12, and it was confirmed that no Zr-Ti composite oxide was present.

[0090]

[0091] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

[0092] [Explanation of the symbol]

[0093] 100 : Electrical steel sheet 10 : Electrical steel sheet material

[0094] 20: Insulating film

Claims

1. 100 parts by weight of silica, 10 to 500 parts by weight of metallic hydrofluoric acid and An insulating film composition for electrical steel sheets comprising 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

2. In Paragraph 1, An insulating film composition for electrical steel sheets further comprising 10 to 100 parts by weight of pigment.

3. In Paragraph 2, The above pigment is an insulating film composition for electrical steel sheets comprising one or more oxides of Mn, Fe, and Cu.

4. In Paragraph 1, The above silica is an insulating film composition for electrical steel sheets having a pH of 8 to 12.

5. In Paragraph 1, The above-mentioned metallic hydrofluoric acid is an insulating film composition for electrical steel sheets comprising one or more of fluorinated titanic acid (F6H2Ti) and fluorinated zirconic acid (F6H2Zr).

6. Electrical steel sheet substrate and It includes an insulating film located on the surface of the electrical steel sheet substrate, and The above insulating film is an electrical steel sheet comprising a composite metal oxide containing two or more types of metals.

7. In Paragraph 6, The above insulating film is an electrical steel sheet comprising 100 parts by weight of silica, 10 to 500 parts by weight of a complex metal oxide, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

8. In Paragraph 6, The above composite metal oxide is an electrical steel sheet containing Zr and Ti.

9. Step of preparing the electrical steel sheet substrate; A step of applying an insulating film composition to the surface of the electrical steel sheet substrate and The method includes a step of heat-treating the above electrical steel sheet substrate, and A method for manufacturing an electrical steel sheet comprising the above insulating film composition comprising 100 parts by weight of silica, 10 to 500 parts by weight of hydrofluoric acid, and 50 to 500 parts by weight of one or more shielding agents selected from dolomite, talc, carbonate, and feldspar.

10. In Paragraph 9, A method for manufacturing an electrical steel sheet in which the heat treatment step is performed at a temperature of 750 to 1000℃ for 10 to 300 seconds.

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