The present invention, grain-oriented electrical steel sheet, and a method of manufacturing a grain-oriented electrical steel sheet.
　This application, on July 13, 2017, claiming priority on Japanese Patent Application No. 2017-137419 filed in Japan, the contents of which are incorporated herein.
BACKGROUND
[0002]
　Oriented electrical steel sheet is a soft magnetic material, mainly because it is used as a core material of a transformer, the magnetic characteristics are required of high magnetic characteristics and low iron loss. Magnetization characteristics is a magnetic flux density induced when exciting the iron core. Higher magnetic flux density is high, it is possible to reduce the size of the core, the higher the magnetization characteristic is advantageous in terms of cost of manufacturing the transformer.
[0003]
　To increase the magnetization characteristics, aligned in parallel to {110} plane in the steel sheet surface, and to form crystal grains aligned with texture in the <100> crystal orientation axes are aligned in the rolling direction (Goss orientation) There is a need. To integrate the crystal orientation Goss orientation, AlN, MnS, and, that by finely precipitated inhibitors such as MnSe, to control the secondary recrystallization, usually performed.
[0004]
　Iron loss, when excited core in an alternating magnetic field, a power loss consumed as heat energy, in terms of energy saving, it is required as low as possible. The level of the iron loss, magnetic susceptibility, thickness, coating tension, the amount of impurities, electrical resistivity, grain size, etc. are affected. Relates electromagnetic steel, even in currently various techniques have been developed, to improve the magnetic properties, research and development to reduce the iron loss is continued constantly.
[0005]
　Another characteristic required of the grain-oriented electrical steel sheet, there is a characteristic of the film formed on the surface of the steel sheet. Usually, in the grain-oriented electrical steel sheet, as shown in FIG. 1, Mg on the steel plate 1 2 SiO 4 forsterite film 2 made mainly of (forsterite) Forsterite film and the insulating film are electrically insulates the surface of the steel sheet also has a function of reducing the iron loss by imparting a tension to the steel sheet.
[0006]
　Note that the forsterite film Mg 2 SiO 4 in addition, impurities or additives contained in the steel sheet and the annealing separating agent, and also their reaction products contained in trace amounts.
[0007]
　Insulating coating, in order to exert the insulation and the required tension insulating coating must not peel from the steel plate is higher coating adhesion is required in the insulation film, the tension and a coating to be applied to the steel sheet to enhance both adhesion simultaneously is not easy, research and development to enhance the tension and coating adhesion imparted to the steel sheet at the same time is continued continuously.
[0008]
　Oriented electrical steel sheet is usually produced by the following procedure. The silicon steel slab containing Si 2.0 ~ 4.0 wt% to hot rolling and hot-rolled steel sheet, if necessary, annealed hot-rolled steel sheet, then, to sandwich the one or intermediate annealing 2 subjected to the above cold rolling once, finish steel final thickness. Thereafter, the steel sheet of the final sheet thickness, subjected to decarburization annealing in a humid hydrogen atmosphere, in addition to decarburization, as well as promote the primary recrystallization, to form an oxide layer on the surface of the steel sheet.
[0009]
　The steel sheet having an oxide layer, an annealing separator composed mainly of MgO (magnesia) and applied and dried, after drying, wound into a coil. Then, finish-annealed into a coil of steel sheet, to promote the secondary recrystallization, by integrating the crystal grains in the Goss orientation, further, SiO oxide layer and MgO in the annealing separator, 2 (silicon oxide, or , silica) were reacted to the surface of the steel sheet, Mg 2 SiO 4 to form a mineral forsterite film composed mainly of.
[0010]
　Then subjected to purification annealing in a steel sheet having a forsterite film, it is removed by diffusing impurities in the steel sheet outwardly. Moreover, subjected to flattening annealing the steel sheet, the steel sheet surface to form an insulating film composed mainly of phosphate and colloidal silica. At this time, between the steel sheet and the insulating film, the tension is applied from the difference in the thermal expansion coefficient.
[0011]
　Mg 2 SiO 4 forsterite film mainly composed of (in FIG. 1 "2") and the steel sheet interface (in FIG. 1 "1") are usually no uneven uneven (Fig. 1, reference) , the interface of the uneven shape, is offset slightly the iron loss reducing effect by tension. To reduce the core loss by smoothing the interface, the following development have been carried out.
[0012]
　Patent Document 1, to remove the forsterite film by means of pickling or the like, a manufacturing method of smoothing the surface of the steel sheet by chemical polishing or electrolytic polishing is disclosed. However, in the manufacturing method of Patent Document 1, the insulating film on the base iron surface there is a problem that it is difficult to contact.
[0013]
　In order to enhance the coating adhesion of the insulating coating on smooth finished steel sheet surface, as shown in FIG. 2, the intermediate layer 4 between the steel sheet and the insulating film (or base coating) it has been proposed to form the . Is effective in Patent Document 2 to the disclosed phosphate or alkali metal silicate solution applied to the base coat also coating adhesion formed by the salt, as a method of further is effective, Patent Document 3, an insulating film prior to the formation of, and annealing the steel sheet in a particular atmosphere, the surface of the steel sheet, a method of forming a silica layer outside oxidized as an intermediate layer is disclosed.
[0014]
　Furthermore, Patent Document 4, before the formation of the insulating film, the surface of the steel sheet, 100 mg / m 2 a method of forming a following external oxidation type silica layer as an intermediate layer is disclosed. Further, Patent Document 5, when the insulating film is an insulating film of crystalline mainly of alumina sol and boric acid compound, a method of forming an outer oxide layer of amorphous, such as silica layer as the intermediate layer is disclosed ing.
[0015]
　These external oxidation type silica layer is formed as an intermediate layer on the surface of the steel sheet, and functions as a base for smooth interface, the improvement of the coating adhesion of the insulating coating, which exert a certain effect. However, in order to ensure the adhesion of the insulating film formed on the external oxidation type silica layer stably, further development has been promoted.
[0016]
　Patent Document 6, the steel plates to smooth the surface, subjected to a heat treatment in an oxidizing atmosphere, the surface of the steel sheet, Fe 2 SiO 4 (fayalite) or (Fe, Mn) 2 SiO 4 crystalline (Kuneberaito) the intermediate layer is formed, a method of forming an insulating coating on is disclosed that.
[0017]
　However, the surface of the steel sheet, Fe 2 SiO 4 or (Fe, Mn) 2 SiO 4 in an oxidizing atmosphere to form a, and Si is oxidized in the steel sheet surface layer, SiO 2 will be oxides such as will precipitate iron loss characteristics are deteriorated.
[0018]
　Further, due to differences in crystal structure, adhesion between the intermediate layer and the insulating film is also a problem that stable.
[0019]
Further, Fe 2 SiO 4 or (Fe, Mn) 2 SiO 4 tension intermediate layer of mainly imparts to the steel sheet surface, SiO 2 intermediate layer mainly composed of is not large enough tension applied to the steel sheet surface there is also a problem in that.
[0020]
　Patent Document 7, the smooth surface of the steel sheet, sol - how gel method, an intermediate layer, to form a 0.1 ~ 0.5 [mu] m thick gel film, on the intermediate layer, the insulating film There has been disclosed. However, the disclosed film formation conditions, general sol - in the range of gel method, and can not be firmly secured to coating adhesion.
[0021]
　Patent Document 8, the smooth surface of the steel sheet, the anode electric field treatment in the aqueous solution of silicate, to form a siliceous film as an intermediate layer, then, a method of forming the insulating coating is disclosed.
[0022]
　Patent Document 9, the smooth surface of the steel sheet, TiO 2 oxides such as (Al, Si, Ti, Cr , 1 or more oxides selected from Y) is present in a layer or an island shape, on its , silica layer is present, further, on the electromagnetic steel sheet insulating coating is present is disclosed.
[0023]
　By forming an intermediate layer such as these, we can improve the coating adhesion, since newly requires large-scale facilities such as electrolytic treatment facilities and dry coating, remains premises secure and economic problems ing.
[0024]
　Patent Document 10, the interface between the tensioning insulating coating and the steel sheet, in addition to an external oxide film having a film thickness mainly composed of silica 2 ~ 500 nm, unidirectional with particulate external oxide based on silica silicon steel sheet is disclosed, Patent Document 11, it is also disclosed oriented silicon steel sheet having 30% or less of the cavity in the cross-sectional area ratio in the external oxide type oxide film mainly made of silica.
[0025]
　Patent Document 12, a smooth surface of the steel sheet, thickness at 2 ~ 500 nm, containing a cross-section area of 30% or less of the metallic iron, SiO 2 to form an external oxide film of the metallic as the intermediate layer, the intermediate layer a method of forming an insulating coating on is disclosed in.
[0026]
　Patent Document 13, a smooth surface of the steel sheet, thickness at 0.005 ~ 1 [mu] m, containing 1 to 70% of metallic iron or iron-containing oxides in a volume fraction, and the metallic silicon oxide glassy the intermediate layer is formed to a method of forming an insulating coating on the intermediate layer is disclosed.
[0027]
　In Patent Document 14, a smooth surface of the steel sheet, thickness at 2 ~ 500 nm, the metallic oxide (Si-Mn-Cr oxide, Si-Mn-Cr-Al -Ti oxides, Fe oxides ) and contains 50% or less in sectional area ratio, SiO 2 to form an external oxide type oxide film mainly as an intermediate layer, a method of forming an insulating coating on the intermediate layer is disclosed.
[0028]
　Thus, SiO 2 intermediate layer entity, granular outer oxide, hollow, metallic iron, iron-containing oxides, or, when containing a metal-based oxide, but improves the coating adhesion of the insulating coating, comprising further improvement is expected.
CITATION
Patent Document
[0029]
Patent Document 1: Japanese Sho 49-096920 Patent Publication
Patent Document 2: Japanese Patent Laid-Open 05-279747 discloses
Patent Document 3: Japanese Patent Laid-Open 06-184762 discloses
Patent Document 4: Japanese Patent 09- 078252 JP
Patent Document 5: Japanese Unexamined Japanese Patent Application Laid-Open No. 07-278833
Patent Document 6: Japanese Patent Laid-Open 08-191010 discloses
Patent Document 7: Japanese Patent Laid-Open 03-130376 discloses
Patent Document 8: Japanese Patent 11-209891 JP
Patent Document 9: Japanese Patent 2004-315880 JP
Patent Document 10: Japanese Patent 2002-322566 JP
Patent Document 11: Japanese Patent 2002-363763 JP
Patent Document 12: Japanese JP 2003-313644 JP
Patent Document 13: Japanese Patent 2003-171773 JP
Patent Document 14: Japanese Patent 2002-348643 Patent Publication No. Broadcast
Summary of the Invention
Problems that the Invention is to Solve
[0030]
　Usually, the film structure of the grain-oriented electrical steel sheet having no forsterite film is a three-layer structure of "a steel sheet - - interlayer insulating film", the interface forms between the steel sheet and the insulating coating is uniform macroscopically in a smooth (Fig. 2, reference). Work is the surface tension between the layers after the heat treatment by the difference in thermal expansion coefficient of each layer, while it is possible to impart tension to the steel sheet, each layer is easily peeled off.
[0031]
　The present invention, on the entire surface of the grain-oriented electrical steel sheet, to form an intermediate layer of silicon oxide entity capable of ensuring the film adhesion and excellent insulating film without plaques (i.e., the intermediate layer containing Si and O) it is an object, and an object thereof is to provide grain-oriented electrical steel sheet, and a method of manufacturing this solves the problem.
Means for Solving the Problems
[0032]
　Conventionally, in order to uniform the film adhesion of the insulating coating, the smooth finished surface of the steel sheet, an intermediate layer of silicon oxide mainly but be more uniform and smooth surface is a conventional method, the present inventors It is, regardless of the conventional method, was conducted extensive research on a method for solving the above-mentioned problems.
[0033]
　As a result, the surface of the grain-oriented electrical steel sheet which has been removed after manufacture of the forsterite film, or the surface of the grain-oriented electrical steel sheet produced by inhibiting the production of forsterite film, the silicon oxide mainly containing a metal phosphide in the coating structure of three layers to form an intermediate layer, it was found to be able to ensure the coating adhesion and excellent insulating film without unevenness.
[0034]
　The present invention has been made based on the above findings and has as its gist is as follows.
(1) grain-oriented electrical steel sheet according to an embodiment of the present invention includes a steel sheet, an intermediate layer comprising a disposed the Si and O on the steel sheet, and an insulating film disposed on the intermediate layer a grain-oriented electrical steel sheet, wherein the intermediate layer contains a metal phosphide, the layer thickness of the intermediate layer is not less 4nm or more, the abundance of the metal phosphide is a cross-sectional area ratio in the cross section of the intermediate layer 1 to 30%.
The oriented electrical steel sheet according to (2) above (1), wherein the metal phosphide, Fe 3 P, Fe 2 P, and may be one or more of Fe phosphide FeP.
(3) In the oriented electrical steel sheet according to (1) or (2), the intermediate layer may contain α iron and / or iron silicate in addition to the metal phosphide.
(4) In the oriented electrical steel sheet according to any one of the above (1) to (3), wherein the metal phosphide, and the abundance of the sum of α iron and / or iron silicate is the intermediate layer sectional area ratio in the cross section may be 1 to 30%.
(5) In the oriented electrical steel sheet according to any one of the above (1) to (4), the layer thickness of the intermediate layer may be less than 400 nm.
(6) In the oriented electrical steel sheet according to any one of the above (1) to (5), the thickness of the insulating film may be 0.1 ~ 10 [mu] m.
(7) In the oriented electrical steel sheet according to any one of the above (1) to (6), the surface roughness of the steel sheet, may be 0.5μm or less in terms of arithmetic average roughness Ra.
Method for producing a grain-oriented electrical steel sheet according to another embodiment of (8) The present invention is a method for producing a grain-oriented electrical steel sheet according to any one of the above (1) to (7), the billet obtaining a hot-rolled steel sheet by hot rolling, obtaining a cold-rolled steel sheet of the hot-rolled steel sheet was cold-rolled, the cold-rolled steel sheet to decarburization annealing, oxidation on the surface of the cold-rolled steel sheet forming a layer, a step of applying the annealing separator to the surface of the cold rolled steel sheet having said oxide layer, after drying the annealing separator, the steps of winding the cold-rolled steel sheet, take- a step of annealing the finish the cold-rolled steel sheet which is a step of applying the first solution, the first solution is further annealing the cold-rolled steel sheet coated, the intermediate layer containing a metal phosphide forming, a step of applying a second solution to the surface of the intermediate layer, the said second solution has been applied Comprising a step of baking the rolled steel sheet, wherein the first solution comprises a phosphoric acid and a metal compound, the mass ratio of the metal compound and the phosphoric acid is 2: 1 to 1: 2, the intermediate in annealing for forming the layer, the annealing temperature of 600 ~ 1150 ° C., the annealing time is 10 to 600 seconds, the dew point in the annealing atmosphere was -20 ~ 2 ° C., the ratio of the hydrogen amount and the amount of nitrogen in the annealing atmosphere 75%: to 25% abundance of the metal phosphide, controls the coating amount of the first solution to a 1 to 30% cross-sectional area ratio in the cross section of the intermediate layer.
(9) The method of producing oriented electrical steel sheet according to the above (8), further, prior to applying the first solution, also comprise the step of removing inorganic mineral coating caused by the finish annealing well, the annealing separator may be composed mainly of magnesia.
Method for producing oriented electrical steel sheet according to (10) above (8) or (9), further comprising, prior to the cold rolling, may be provided with a step of annealing said hot-rolled steel sheet.
The invention's effect
[0035]
　According to the present invention, the entire surface of the steel sheet, metal phosphides, and other, as appropriate, alpha containing iron and / or iron silicate, silicon oxide entity capable of ensuring the film adhesion and excellent insulating film without unevenness it is possible to provide grain-oriented electrical steel sheet comprising an intermediate layer, and a method of manufacturing it.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036]
[1] a coating structure of a conventional grain-oriented electrical steel sheet is a diagram schematically illustrating.
[2] Another coating structure of a conventional grain-oriented electrical steel sheet is a diagram schematically illustrating.
3 is a diagram schematically showing a film structure of the grain-oriented electrical steel sheet of the present invention.
4 is a diagram showing a method of manufacturing a grain-oriented electrical steel sheet of the present invention.
DESCRIPTION OF THE INVENTION
[0037]
　Excellent oriented electrical steel sheet coating adhesion according to one embodiment of the present invention (hereinafter sometimes referred to as "electromagnetic steel sheet according to the present embodiment".), The intermediate layer of silicon oxide mainly formed on the surface of the steel sheet (i.e., on the intermediate layer) containing Si and O, a grain-oriented electrical steel sheet with an insulating coating, specifically, on the surface of the forsterite film without oriented electrical steel sheet on the surface, an intermediate silicon oxide mainly a layer, on the intermediate layer, in the grain oriented electrical steel sheet having an insulation coating composed mainly of phosphate and colloidal silica, the intermediate layer contains a metal phosphide, the layer thickness of the intermediate layer and a 4nm or more, the presence of the metal phosphide, characterized in that 1 to 30% cross-sectional area ratio in the cross section of the intermediate layer. In other words, the electromagnetic steel sheet according to the present embodiment includes a steel plate 1, an intermediate layer 4 containing Si and O arranged on the steel sheet 1, an insulating film 3 disposed on the intermediate layer 4 , wherein the intermediate layer 4 containing a metal phosphide. 5, the layer thickness of the intermediate layer 4 is 4nm or more, the abundance of metal phosphide 5 1 to 30% cross-sectional area ratio in the cross section of the intermediate layer 4 it is.
[0038]
　Here, forsterite uncoated oriented electrical steel sheet on the surface, the grain-oriented electrical steel sheet was removed after manufacture of the forsterite film, or a oriented electrical steel sheet produced by suppressing the formation of forsterite coating.
[0039]
　The following describes an electromagnetic steel sheet according to the present embodiment.
[0040]
　3, a film structure of an electromagnetic steel sheet according to the embodiment shown schematically. As shown in FIG. 3, the surface of the steel sheet 1, an intermediate layer 4 of silicon oxide mainly containing the metal phosphide 5 is formed, on its insulating film 3 is formed. Intermediate layer 4 of silicon oxide entity, other metal phosphides 5 may contain α iron and / or iron silicate. It will be described in detail below.
[0041]
　Insulating coating
　insulating coating on the intermediate layer of silicon oxide mainly phosphate and colloidal silica (SiO 2 as an insulating film for baked formed by applying a solution mainly composed of). The insulating coating can impart a high surface tension to the steel sheet.
[0042]
　However, when the thickness of the insulating coating is less than 0.1 [mu] m, since it is difficult to impart the required surface tension in the steel sheet, the thickness of the insulating coating is preferably at least 0.1 [mu] m. More preferably 0.5μm or more, 0.8 [mu] m or more, 1.0 .mu.m or more, or 2.0μm or more. On the other hand, when the thickness of the insulating film exceeds 10 [mu] m, the formation step of the insulating coating, since there is a possibility that cracks occur in the insulating film, the film thickness of the insulating coating is preferably 10 [mu] m or less. More preferably 5μm or less, 4.5 [mu] m or less, 4.2 .mu.m or less, or 4.0μm or less.
[0043]
　Note that the insulating film, if necessary, laser, plasma, mechanical methods, etching, and other methods may be subjected to magnetic domain refining process of adding a local small distortion.
[0044]
　An intermediate layer of silicon oxide main
　intermediate layer according to the present embodiment includes a Si and O, further comprising a metal phosphide. Intermediate layer according to the present embodiment may further contain impurities. Such an intermediate layer, in the present embodiment, referred to as an intermediate layer of silicon oxide mainly. Coating structure (Fig. 2, reference) of the three-layer structure in the intermediate layer of silicon oxide mainly has the function of adhering the steel plate and the insulating film on the entire surface of the steel sheet, an intermediate layer of silicon oxide mainly plaques be formed by firmly adhered with no uniform adhesion is not easy from the prior art.
[0045]
　Accordingly, the present inventors, the intermediate layer, rather than the intermediate layer of silicon oxide alone, if the intermediate layer and the silicon oxide and crystalline material is combined, in the presence of crystalline material, the intermediate layer and the steel sheet but conceived that it would be firmly adhered at spots without uniform adhesion, the surface of the steel sheet, to form an intermediate layer of silicon oxide mainly containing materials of various crystalline, the intermediate layer and the steel sheet They were tested for adhesion.
[0046]
　As a result, an intermediate layer of silicon oxide mainly containing the metal phosphide, the entire surface of the steel sheet was found to strongly adhere. The reason is that the shape of the metal phosphide present in the intermediate layer of silicon oxide mainly irregular considered to flexibility of the intermediate layer is because improved.
[0047]
　Typically, in a grain-oriented electrical steel sheet, as shown in FIG. 1, Mg on the steel plate 1 2 SiO 4 forsterite film 2 made mainly of (forsterite) Is evaluated by the surface roughness, the surface of the uneven shape has contributed greatly to the adhesion between the steel sheet and the insulating film, there is a to increase the surface roughness is needed for improving adhesion. However, in the oriented electrical steel sheet according to the present embodiment, improvement in the flexibility of the intermediate layer of silicon oxide principal, it is considered that greatly affects the improvement of adhesion to the steel sheet surface, the steel sheet forming the intermediate layer surface roughness is not limited particularly to a specific range. In terms of a problem of the invention improving adhesion are desirably large surface roughness, in that by applying a large tension to the steel sheet reduced iron loss, an arithmetic mean roughness (Ra) 0.5 [mu] m or less, more preferably 0.3 [mu] m. The oriented electrical steel sheet according to the present embodiment, even if the steel sheet surface was smooth, intermediate layer according to the present embodiment can ensure the adhesion of the insulating coating.
[0048]
　Also the thickness of the steel sheet is not limited particularly to a specific range, to further reduce the iron loss, the thickness is preferably 0.35mm or less, more preferably 0.30 mm.
[0049]
　In the intermediate layer of silicon oxide mainly containing a metal phosphide (hereinafter sometimes referred to as "intermediate layer according to the present embodiment".), Silicon oxide SiO X (x = 1.0 ~ 2.0) is preferable. If x = 1.5 ~ 2.0, since the silicon oxide is more stable, more preferred. If sufficiently performed oxidation annealing to form the intermediate layer according to the present embodiment, SiO of x ≒ 2.0 X can be formed.
[0050]
　By performing the oxidation annealing at normal temperature (1150 ° C. or less), which has a high strength to withstand the thermal stress and the elastic modulus relatively small, the thermal stress can be easily relaxed, this embodiment having a dense material properties the intermediate layer according to the may be formed on the surface of the steel sheet.
[0051]
　Steel sheet, high concentrations of Si (e.g., 0.80 to 4.00 wt%) because it contains a strong chemical affinity is expressed between the intermediate layer according to the present embodiment, the present embodiment intermediate layer and the steel sheet is firmly adhered.
[0052]
　If the thickness of the intermediate layer according to the present embodiment is thin, the thermal stress relaxation effect is not exhibited sufficiently, the thickness of the intermediate layer according to the present embodiment shall not be less than 4 nm. Preferably 5nm or more, 10 nm or more, 20 nm or more, or 50nm or more. On the other hand, the upper limit of the intermediate layer according to the present embodiment, the layer thickness is uniform, and is not limited as long as there is no defect such as voids or cracks, the layer thickness is too thick, the layer thickness becomes uneven or, also, since there is a fear that defects such as voids and cracks enter, the layer thickness of the intermediate layer according to the present embodiment is preferably less than 400 nm. More preferably 300nm or less, 250 nm or less, 200 nm or less, or 100nm or less.
[0053]
　Metal phosphides containing intermediate layer according to the present embodiment, Fe 3 P, Fe 2 P, and, one or more kinds of Fe phosphides of FeP preferred. Fe is because it is a constituent element of a steel plate, in the metal phosphide also, Fe 3 P, Fe 2 P, and, FeP is, contribute are greatly to the improvement of adhesion between the intermediate layer and the steel sheet according to the embodiment it is conceivable that.
[0054]
　Abundance of metal phosphide present in the intermediate layer according to the present embodiment, the ratio of the cross-sectional area of ​​the total metal phosphide to the cross-sectional area of ​​the entire intermediate layer including the metal phosphide (hereinafter referred to as "cross-sectional area ratio" be displayed in a certain.) it is.
[0055]
　Sectional area of ​​the metal phosphide is small (the amount present is small), metal phosphides does not contribute to improving the flexibility of the intermediate layer, since the required adhesion can not be obtained to the steel sheet, the cross-sectional area ratio 1% or more is preferable. More preferably 2% or more, 5% or more, 10% or more, or 15% or more.
[0056]
　On the other hand, the cross-sectional area of ​​the metal phosphide is as large as (abundance is large), the proportion of silicon oxide is reduced, since the adhesion of the intermediate layer and the insulating film is reduced, the cross-sectional area ratio is preferably 30% or less . More preferably 27% or less, 25% or less, 20% or less, or 18% or less.
[0057]
　Intermediate layer according to the present embodiment, other metal phosphides, may contain α iron and / or iron silicate. α iron is iron ferrite phase, which is a main constituent element of the steel sheet. Iron silicate produces an oxidizing annealing steel, crystalline Fe 2 SiO 4 is (fayalite), FeSiO 3 a (Feroshiraito) may contain trace amounts.
[0058]
　α iron main constituent elements of the steel sheet, and / or, the steel sheet chemically iron silicate which affinity is due to the presence of the intermediate layer of silicon oxide mainly thermal sensitivity of the intermediate layer close to the heat sensitivity of the steel sheet , increased flexibility of the intermediate layer, the adhesion of the intermediate layer and the steel sheet is improved. However, even if the intermediate layer comprises α iron and / or iron silicate, in the middle layer abundance as metal phosphides described above must be between 1 and 30% cross-sectional area ratio.
[0059]
　"Metal phosphide, and, alpha iron and / or iron silicate" present in the intermediate layer according to the present embodiment abundance of "metal phosphides and, alpha iron and / or iron silicate" intermediate layer including to the total cross-sectional area "a metal phosphide, and, alpha iron and / or iron silicate" displays the ratio of the cross-sectional area of ​​the sum of (the total cross-sectional area ratio).
[0060]
　Even if the intermediate layer comprises α iron and / or iron silicate, in the middle layer abundance as metal phosphides described above must be between 1 and 30% cross-sectional area ratio. Also, alpha iron and / or iron silicate is not an essential component of the intermediate layer according to the present embodiment. Thus, "metal phosphides and, alpha iron and / or iron silicate" total cross sectional area ratio of 1% or more. More preferably, the metal phosphide, and, alpha iron and / or total cross-sectional area ratio of iron silicate is 2% or more, 5% or more, 10% or more, or 15% or more.
[0061]
　On the other hand, "metal phosphides and, alpha iron and / or iron silicate" and the total cross-sectional area of ​​the larger (abundance large), decreases the proportion of silicon oxide in the intermediate layer is, the adhesion of the insulating coating and the intermediate layer since sex is reduced, the total cross-sectional area ratio is preferably 30% or less. More preferably 27% or less, 25% or less, 20% or less, or 18% or less.
[0062]
　"Metal phosphide, and, alpha iron and / or iron silicate" present in the intermediate layer according to the present embodiment when the particle size (average value of equivalent circle diameter) is small, operation and effect of alleviating the thermal stress is reduced since, the particle size is preferably at least 1 nm. More preferably 3nm or more.
[0063]
　On the other hand, "metal phosphides and, alpha iron and / or iron silicate" the particle diameter is large, "metal phosphides and, alpha iron and / or iron silicate" is, since it can be a starting point of fracture due to stress concentration the particle size, "metal phosphides and, alpha iron and / or iron silicate" below 2/3 of the layer thickness of the intermediate layer of silicon oxide mainly including preferred. More or less half of the layer thickness of the intermediate layer preferably.
[0064]
　Wherein the electromagnetic steel sheet according to the present embodiment, metal phosphides, and other, as appropriate, an intermediate layer of silicon oxide mainly containing α iron and / or iron silicate, since the chemical composition of the product steel sheet not directly related, but it is not limited to chemical composition, especially of the electromagnetic steel sheet according to the present embodiment, since the grain-oriented electrical steel sheet is manufactured through a variety of processes, preferably steel material pieces in manufacturing electrical steel sheet according to the present embodiment (slabs) and described component composition of the steel sheet 1 (the base steel sheet). Hereinafter,% of the component composition refers to mass%.
[0065]
　Composition of the base material steel plate
　base material steel plate of electrical steel sheet according to the present embodiment, for example, Si: contains 0.8 ~ 7.0%, C: 0.005 % or less, N: 0.005% or less , S + Se: 0.005% or less, and acid-soluble Al: limited to 0.005% or less, the balance being Fe and impurities.
[0066]
　Si: 0.8 ~
　7.0% Si (silicon) reduces the iron loss by increasing the electrical resistance of the grain-oriented electrical steel sheet. Si content is preferably 0.8% or more, or 2.0% or more. On the other hand, when the Si content exceeds 7.0%, the saturation magnetic flux density of the base material steel plate is lowered, it becomes hard to reduce the size of the iron core used in a high magnetic flux density. For the above reasons, Si content is preferably not more than 7.0%.
[0067]
　C: 0.005% or less
　C (carbon) forms a compound in the base steel sheet in order to degrade the iron loss, the less preferred. C content is preferably limited to 0.005% or less. C content is preferably 0.004% or less, or 0.003% or less. C, since the less preferred, the lower limit includes 0% and to reduce C to less than 0.0001%, the manufacturing cost increases greatly, the production, is 0.0001% is substantially the lower .
[0068]
　N: 0.005% or less
　N (nitrogen) forms a compound in the base steel sheet in order to degrade the iron loss, the less preferred. N content is preferably limited to 0.005% or less. The preferable upper limit of the N content is 0.004%, more preferably 0.003%. N, since the less preferred, the lower limit need only be 0%.
[0069]
　S, Se: 0.005% respectively less
　S (sulfur) and Se (selenium) forms a compound in the base steel sheet in order to degrade the iron loss, the less preferred. It is preferable that the content of each S and Se in 0.005% or less, further, it is preferable to limit the total of both the S and Se to below 0.005%. The content of each S and Se is more preferably 0.004% or less, or 0.003% or less. Since the less preferred, the lower limit of the content of each S and Se, respectively may be a 0%.
[0070]
　Acid-soluble Al: 0.005% or less
　acid-soluble Al (acid soluble Aluminum) is to form a compound base steel sheet in order to degrade the iron loss, the less preferred. It is preferable acid-soluble Al is 0.005% or less. Acid-soluble Al is more preferably 0.004% or less, or 0.003% or less. Since the acid-soluble Al is as small as possible preferably, the lower limit need only be 0%.
[0071]
　Balance of composition of the base material steel plate described above is Fe and impurities. Note that the "impurities", in manufacturing the steel industrially, refers to those mixed ores as raw material, scrap or from the manufacturing environment and the like.
[0072]
　Also, the base material steel plate of electrical steel sheet according to the present embodiment, in a range that does not disturb a property as a selective element in place of part of Fe is the balance, for example, Mn (manganese), Bi (bismuth), B (boron), Ti (titanium), Nb (niobium), V (vanadium), Sn (tin), Sb (antimony), Cr (chromium), Cu (copper), P (phosphorus), Ni (nickel), Mo it may contain at least one selected from (molybdenum).
[0073]
　The content of the selected element as described above may be, for example, less. The lower limit of the selection element is not particularly limited, the lower limit may be 0%. Moreover, even if these optional elements is contained as an impurity, the effect of the electromagnetic steel sheet according to the present embodiment is not impaired.
　Mn: 0% or more and 0.15% or
　less, Bi: 0% or more and 0.010% or
　less, B: 0% or more and 0.080% or
　less, Ti: 0% or more and 0.015% or
　less, Nb: 0% or more and 0.20% or
　less, V: 0% or more and 0.15% or
　less, Sn: 0% or more and 0.30% or
　less, Sb: 0% or more and 0.30% or
　less, Cr: 0% not more than 0.30% or less,
　Cu: 0% or more and 0.40% or
　less, P: 0% or more and 0.50% or
　less, Ni: 0% or more and 1.00% or less, and
　Mo: 0% or more and 0.10% or less.
[0074]
　A preferred composition of the material billet (slab)
　Since C is an effective element in controlling the primary recrystallized texture, it is preferred to limit its content to 0.005% or more. C content is more preferably 0.02%, more preferably 0.04%, further preferably 0.05% or more. When C exceeds 0.085% decarburization in decarburization process does not proceed sufficiently, since the required magnetic properties are not obtained, C is preferably less 0.085%. More preferably 0.065% or less.
[0075]
　When Si is less than 0.80%, austenite transformation occurs during finish annealing, since accumulation in grain Goss orientation is inhibited, Si is preferably at least 0.80%. On the other hand, when it exceeds 4.00% the workability is deteriorated and curing the steel plate, it is necessary that the equipment measures such as so cold rolling becomes difficult warm rolling. From the viewpoint of processability, Si is preferably not more than 4.00%. More preferably not more than 3.80%.
[0076]
　When Mn is less than 0.03%, the toughness is lowered, so cracks hot rolling is likely to occur, Mn is preferably at least 0.03%. More preferably 0.06% or more. On the other hand, when it exceeds 0.15%, MnS and / or MnSe is large amount and unevenly generated, since the secondary recrystallization does not proceed stably, Mn is preferably 0.15% or less. More preferably not more than 0.13%.
[0077]
　When the acid-soluble Al is less than 0.010%, insufficient precipitation amount of AlN that functions as inhibitor, since the secondary recrystallization does not proceed stably and sufficiently, acid-soluble Al is preferably 0.010% or more . More preferably 0.015% or more. On the other hand, if it exceeds 0.065%, AlN is coarsened, since the function as an inhibitor decreases, acid-soluble Al is preferably 0.065% or less. More preferably 0.060% or less.
[0078]
　If N is less than 0.004% or, insufficient precipitation amount of AlN that functions as inhibitor, since the secondary recrystallization does not proceed stably and sufficiently, N is preferably 0.004% or more. More preferably 0.006% or more. On the other hand, if it exceeds 0.015%, nitride during hot rolling is a large amount and unevenly deposited, since hinders the progress of recrystallization, N represents preferably 0.015% or less. More preferably not more than 0.013%.
[0079]
　If the total of one or both of S and Se is less than 0.005%, insufficient precipitation amount of MnS and / or MnSe functioning as inhibitors, since the secondary recrystallization does not proceed sufficiently stable, S and the sum of one or both of Se is preferably 0.005% or more. More preferably 0.007% or more. On the other hand, if it exceeds 0.050% during final annealing, purification is insufficient, since iron loss is reduced, the total of one or both of S and Se is preferably 0.050% or less. More preferably not more than 0.045%.
[0080]
　The remainder of the chemical components described above is Fe and impurities. The impurities, in producing the steel industrially, a component mixed by various factors, such raw materials or manufacturing processes as ores or scraps are allowed in a range in the present invention does not adversely affect It means a thing. Furthermore, material steel piece, in a range that does not inhibit the characteristics of an electromagnetic steel sheet according to the present embodiment, other elements, for example, P, Cu, Ni, Sn, and contain one or more of Sb it may be.
[0081]
　P is increased the resistivity of the base material steel plate, but an element which contributes to the reduction of iron loss, when it exceeds 0.50%, since the rolling resistance decreases excessively increased hardness, 0.50 % or less is preferable. More preferably not more than 0.35%.
[0082]
　Cu forms fine CuS and CuSe functioning as an inhibitor, but an element contributing to the improvement of the magnetic properties, when it exceeds 0.40%, the effect of improving magnetic properties becomes saturated, hot rolling, surface it may cause flaws, preferably 0.40% or less. More preferably not more than 0.35%.
[0083]
　Ni is to enhance the electrical resistivity of the base material steel plate, but an element which contributes to the reduction of iron loss, when it exceeds 1.00%, the secondary recrystallization becomes unstable, Ni 1.00 % or less is preferable. More preferably not more than 0.75%.
[0084]
　Sn and Sb is segregated at grain boundaries, during decarburization annealing, is an element of an action of adjusting the degree of oxidation, it exceeds 0.30%, during the decarburization annealing, it decarburization hardly progresses since, Sn and Sb are both preferably 0.30% or less. More preferably, each element also below 0.25%.
[0085]
　Further, the steel material piece, as an element for forming the inhibitor, Cr, Mo, V, Bi, Nb, and one or more of Ti, may contain a supplementary. The lower limit of these elements is not particularly limited, each may be a 0%. The upper limit of these elements is 0.30%, respectively, 0.10%, 0.15%, 0.010%, may be a 0.20%, or 0.0150%.
[0086]
　It will now be discussed means for identifying the configuration of oriented electrical steel sheet according to the present embodiment. For convenience, the evaluation method of the component is not an element of the oriented electrical steel sheet according to the present embodiment is also combined will be described.
[0087]
　Test pieces were cut out from the oriented electrical steel sheet having an insulating film, a film structure of the specimen, scanning electron microscope (SEM: Scanning Electron Microscope) or transmission electron microscope observation with (TEM Transmission Electron Microscope).
[0088]
　Specifically, first, the cutting direction is cut out a test specimen so as to be parallel to the thickness direction (specifically, a test piece so that the cut surface becomes the thickness direction and parallel to and rolling direction perpendicular cut), the cross-sectional structure of the cut surface is observed with SEM at a magnification of each layer enters into the observation field. For example, by looking at the reflection electron composition image (COMP image), or cross-sectional structure is composed of many layers it can be inferred. For example, the COMP image, the steel sheet can be determined pale, intermediate layer dark, the insulating film as an intermediate color.
[0089]
　To identify each of the cross-sectional structure, using SEM-EDS (Energy Dispersive X-ray Spectroscopy), perform line analysis along a thickness direction, a quantitative analysis of chemical components of each layer. Element for quantitatively analyzing is Fe, P, Si, O, and 5 elements Mg.
[0090]
　Quantitative analysis of the observation results and the SEM-EDS in COMP image described above, a region where the Fe content is measurement noise except 80 atomic% or more, and a line of scanning lines of line analysis for this region if min (thickness) is 300nm or more, the area is determined to be the base steel sheet, a region excluding the base steel sheet, it is determined that the intermediate layer and the insulating film. Note that the "measurement noise" is a noise in the graph showing the line analysis results.
[0091]
　With respect to those regions except the specified base material steel plate above, except the quantitative analysis results of observation and SEM-EDS in COMP image, Fe content except measurement noise less than 80 atomic%, P content is the measurement noise 5 atomic% more than Te, Si content except measurement noise less than 20 atomic%, and O content except measurement noise 50 atomic% to 10 atomic% or less Mg content except the measurement noise, the an area, and the line segment of the scanning line of the line analysis corresponding to this region (thickness) if at 300nm or more, determines the area to be insulated coating.
[0092]
　Incidentally, when determining the area which is above the insulating coating, without a like precipitates and inclusions contained in the insulating film on the judgment of the subject, the region satisfying the above-mentioned quantitative analysis resulting matrix insulator it is determined that the coating. For example, if it is confirmed from the COMP image or line analysis results and precipitates and inclusions on a scanning line of the line analysis exists in the insulating film by quantitative analysis of the matrix phase not put this area to target it is determined whether or not there. Incidentally, precipitates and inclusions, indistinguishable from the parent phase by the contrast in the COMP image, the quantitative analysis can be distinguished from the parent phase by the presence of the constituent elements.
[0093]
　A region excluding the identified base material steel plate and the insulating coating in the above, and if the line segment on the scan line of the line analysis corresponding to this region (thickness) is 300nm or more, if there the area in the middle layer to decide.
[0094]
　The measurement of the above COMP image observation and SEM-EDS quantitative analysis each specific and thickness by, by changing the observation field is carried out in five locations or more. The thickness of the intermediate layer and the insulating film obtained in five or more locations, the maximum and minimum values ​​from the values ​​excluding the seeking average value, the average thickness of the average value intermediate layer, and the average thickness of the insulating coating to be.
[0095]
　Incidentally, at least one 5 or more locations of the observation field as described above, if the line segment of the scanning line of the line analysis (thickness) is present a layer less than 300 nm, observing in detail the appropriate layer by TEM and, the measurement of specific and thickness of the layers corresponding with TEM.
[0096]
　Test pieces comprising a layer to be observed in detail by using TEM, the cut as the cutting direction is parallel to the thickness direction (in detail, so that the cutting surface is the plate thickness direction and parallel to and rolling direction perpendicular cut) the test piece, a cross sectional structure of the cut surface is observed at a magnification of layers corresponding in the observation field of view enters in STEM (Scanning-TEM) (bright field image).
[0097]
　To identify each of the cross-sectional structure, using the TEM-EDS, perform line analysis along a thickness direction, a quantitative analysis of chemical components of each layer. Element for quantitatively analyzing is Fe, P, Si, O, and 5 elements Mg.
[0098]
　Quantitative analysis of bright field image observation and TEM-EDS in TEM described above, to identify the respective layers, the measurement of the thickness of each layer.
[0099]
　Regions Fe content is 80 atomic% or more except for measurement noise is determined that the base steel sheet, a region excluding the base steel sheet, it is determined that the intermediate layer and the insulating film.
[0100]
　With respect to those regions except the specified base material steel plate above, except the quantitative analysis of the observations and the TEM-EDS in COMP image, Fe content except measurement noise less than 80 atomic%, P content is the measurement noise 5 atomic% more than Te, Si content except measurement noise less than 20 atomic%, and O content except measurement noise 50 atomic% or more, and 10 atomic% or less Mg content except the measurement noise region the it is determined that the insulating coating. Incidentally, when determining the area which is above the insulating coating, without a like precipitates and inclusions contained in the insulating film on the judgment of the subject, the region satisfying the above-mentioned quantitative analysis resulting matrix insulator it is determined that the coating.
[0101]
　Determining an area excluding the specified base material steel plate and the insulating coating in the above that the intermediate layer.
[0102]
　The intermediate layer and the insulating film as specified above, to measure the line segment (thickness) by a scanning line of the line analysis. Incidentally, when the thickness of each layer is 5nm or less, it is preferable to use a TEM having a spherical aberration correction function in terms of spatial resolution. Further, when the thickness of each layer is 5nm or less, performs a point analysis at 2nm intervals along the thickness direction, to measure the respective layers of the segments (thickness), adopting the line segment as the thickness of each layer it may be.
[0103]
　The observed and measured in the above TEM, by changing the observation field were performed at five or more locations, the measurement results obtained in a total of five points or more, with an average value from the values ​​excluding the maximum value and the minimum value, the adopting the mean value as the average thickness of the corresponding layers.
[0104]
　Incidentally, the above-mentioned base steel sheet, intermediate layer, and Fe contained in the insulating film, P, Si, O, content such as Mg is the base steel sheet, intermediate layer, and criteria for identifying insulation coating is there. The base steel sheet of electrical steel sheet according to the present embodiment, the intermediate layer, and the chemical composition of the insulating coating is not particularly limited.
[0105]
　Then, the metal phosphide it is confirmed whether present in the intermediate layer as specified above.
[0106]
　Based on specific results of the above test pieces including the intermediate layer, cut into cutting direction is parallel to the thickness direction (particularly, as the cutting surface is the plate thickness direction and parallel to and rolling direction perpendicular test pieces were cut out), the cross-sectional structure of the cut surface is observed with TEM at a magnification of the intermediate layer enters into the observation field.
[0107]
　Verify precipitated phases present in the intermediate layer at any five or more locations of the bright-field image, performs identification of the crystalline phase from the analysis of the crystal structure by the electron beam diffraction for this deposition phase, analysis points by TEM-EDS, to confirm its component elements.
　Specifically, with respect to precipitation phase dealt with the above, performs electron diffraction squeezed electron beam so that the information from only the precipitate phase of the subject is obtained, a target from the electron diffraction pattern to identify the crystal structure of the crystalline phase. This identification may be performed by using the ICDD (International Centre for Diffraction Data) of the PDF (Powder Diffraction File). From electron diffraction results, essentially crystalline phase, Fe 3 P, Fe 2 P, FeP, FeP 2 , and Fe, Fe 2 SiO 4 whether the can be determined.
　Incidentally, the crystalline phase is Fe 3 Identification of whether the P is, PDF: No. It may be carried out based on 01-089-2712. Crystalline phase is Fe 2 Identification of whether the P is, PDF: No. It may be carried out based on 01-078-6749. Identified crystalline phase if it were a FeP is, PDF: No. It may be carried out based on 03-065-2595. Crystalline phase is FeP 2Or of identification is is, PDF: No. It may be carried out based on 01-089-2261. If identified based crystalline phase above the PDF, it is sufficient to identify the tolerance ± 3 ° tolerance ± 5% and inter-plane angle of the surface interval.
　As a result of the analysis points by TEM-EDS, is at P content of the crystalline phase of interest is 30 atomic% or more, as long and the total amount of the P content and the amount of metal element is 70 atomic% or more, this crystalline phase can be confirmed that the metal phosphide. Also, P content of crystalline phase in question is less than 30 atomic%, if the Fe content is 70 atomic% or more, the crystalline phase can be confirmed that the α iron. Is less than 30 atomic% P content of crystalline phase of interest, and the Fe content of 10 atomic% or more, if Si content is 5 atomic% or more, the crystalline phases with iron silicate and it can be confirmed.
　Performing at least 5 or more, the identification and confirmation of the total of 25 or more crystalline phases at each location.
[0108]
　The intermediate layer was specified above, and based on the particular metal phosphides above, determine the area fraction of metal phosphide by image analysis. Specifically, the metal from the total cross-sectional area of ​​the intermediate layer present the electron beam irradiation carried out within the area five or more locations of the observation field, the total cross sectional area of ​​the metal phosphide present in the intermediate layer phosphorus determine the area fraction of the monster. For example, the total cross-sectional area of ​​the metal phosphide, a value obtained by dividing by the total cross sectional area of ​​the intermediate layer is employed as an average area fraction of metal phosphide. Incidentally, the binarized image for image analysis is based on the identification results of the metal phosphide, the image binarized by performing the coloring interlayer and the metal phosphide manually to tissue Photos it may be.
[0109]
　Further, based on metal phosphides specified above, finding the circle equivalent diameter of the metal phosphide by image analysis. Calculated equivalent circle diameter of at least 5 or more metal phosphide in the respective five or more locations of the observation field of view, and the average value by excluding the maximum and minimum values ​​from the equivalent circle diameter determined, metals and the average value employing as the average circle equivalent diameter of phosphide. Incidentally, the binarized image for image analysis is based on the identification results of the metal phosphide, the image may be binarized by performing a coloring metal phosphide manually to tissue Photos .
[0110]
　Surface roughness of the steel sheet, JIS B 0633: Based on the 2001, it can be measured using a stylus type surface roughness diameter. Here, if the material steel sheet before the intermediate layer and the insulating coating is formed is available, it is sufficient that the material steel sheet measured. On the other hand, if only the grain-oriented electrical steel sheet intermediate layer and the insulating film is formed is available, may be performed to measure the above after appropriately removing the insulating film by a known method. Since the thickness of the intermediate layer is small, it would not affect the surface roughness measurement results of the steel sheet. Thus, removal of the intermediate layer is not essential.
[0111]
　Coating adhesion of the insulating coating is evaluated by a bend adhesion test. A flat test piece 80 mm × 80 mm, after winding the oriented electrical steel sheet into a round bar having a diameter of 20 mm, flat stretch, the area of ​​the insulating film which is not separated from the electromagnetic steel sheet were measured, no peeling the value obtained by dividing the area by the area of ​​the steel plate to define a film residual area ratio (%), to evaluate the coating adhesion of the insulating coating. For example, a transparent film with a 1mm grid tick marks placed on the specimen may be calculated by measuring the area of ​​the insulating film is not peeled off.
[0112]
　Next, a method for manufacturing a grain-oriented electrical steel sheet according to the present embodiment. According to the findings of the present inventors, the production method of the grain-oriented electrical steel sheet according to the present embodiment is described below, it is possible to produce a grain-oriented electrical steel sheet according to the present embodiment described above. However, even a grain oriented electrical steel sheet obtained by the manufacturing method is not a method of manufacturing the electrical steel sheet according to the present embodiment, as long as it satisfies the above requirements, the entire surface, unevenness and excellent without insulation an intermediate layer of silicon oxide entity capable of ensuring the film adhesion of the coating (i.e., the intermediate layer containing Si and O) are formed. Therefore, grain-oriented electrical steel sheet meeting the above requirements, regardless of its production method, a grain-oriented electrical steel sheet according to the present embodiment.
[0113]
　Method for producing a magnetic steel sheet according to the present embodiment (hereinafter sometimes referred to as "production method according to the present embodiment".), As shown in FIG. 4, to obtain a hot-rolled steel sheet and steel strip by hot rolling a step, if necessary, a step of performing annealing hot-rolled steel sheet, obtaining a cold-rolled steel sheet hot-rolled steel sheet was cold-rolled, cold-rolled steel sheet to decarburization annealing, the surface of the cold rolled steel sheet forming an oxide layer, a step of applying the annealing separator to the surface of the cold rolled steel sheet having an oxide layer, after drying the annealing separator, the steps of winding the cold-rolled steel sheet was wound cold a step of annealing finish-rolled steel sheet, a step of applying a first solution, and further annealed cold-rolled steel sheet in which the first solution has been applied, the step (a thermal oxidation to form an intermediate layer containing a metal phosphide and annealing), a step of applying a second solution on the surface of the intermediate layer, baked to cold-rolled steel sheet in which the second solution has been applied And a step of the only, the first solution comprises a phosphoric acid and a metal compound, the mass ratio of the phosphoric acid and the metal compound is 2: 1 to 1: 2, annealing for forming the intermediate layer in the annealing temperature of 600 ~ 1150 ° C., the annealing time is 10 to 600 seconds, the dew point in the annealing atmosphere was -20 ~ 2 ℃, 75% a ratio of hydrogen quantity and the amount of nitrogen in the annealing atmosphere of a 25% abundance of metal phosphide, and controlling the coating amount of the first solution to a 1 to 30% cross-sectional area ratio in the cross section of the intermediate layer. Method for producing a grain-oriented electrical steel sheet, before applying the first solution may comprise a step of removing the inorganic mineral coating caused by finish annealing, wherein the annealing separator is mainly composed of magnesia it may be the one. Of these, at (a) finish annealing, a coating of inorganic mineral forsterite or the like produced on the surface of the steel sheet, pickling, the surface of the grain oriented electrical steel sheets removed in means grinding or the like, or, (b) Finishing in annealing, the surface of the grain-oriented electrical steel sheet which suppresses the generation of the film of the inorganic mineral, a solution containing a compound comprising a phosphoric acid, a metal element that produces a metal phosphide reacts with phosphoric acid (first solution) the was coated annealed, to form an intermediate layer of silicon oxide mainly containing a metal phosphide, on the intermediate layer, composed mainly of phosphate and colloidal silica
[0114]
　Forsterite, etc. pickling a coating of inorganic minerals, the grain-oriented electrical steel sheet was removed by means of grinding or the like, and, grain-oriented electrical steel sheet which suppresses the formation of oxide layers of the inorganic mineral, for example, as follows to to be manufactured.
[0115]
　The silicon steel strips containing Si 2.0 ~ 4.0 wt% to hot rolling and hot-rolled steel sheet, if necessary, annealed hot-rolled steel sheet, then the hot-rolled steel plate or annealed hot-rolled steel sheet , one cold rolling, or is subjected to two or more cold rolling sandwiching the intermediate annealing, final sheet finished to steel plate having a thickness, then with performing decarburization annealing the steel plate is allowed to proceed primary recrystallization . The decarburization annealing, an oxide layer is formed on the surface of the steel sheet. Note annealing the hot-rolled steel sheet (so-called hot-rolled sheet annealing) is not essential, but may be implemented for product characteristics improve.
[0116]
　Then, an annealing separator composed mainly of magnesia on the surface of the steel sheet having an oxide layer was applied and dried, after drying, wound in a coil shape, subjected to finish annealing (secondary recrystallization). The finish annealing, the steel sheet surface, forsterite (Mg 2 SiO 4 is forsterite film mainly comprising) After removal, preferably smoothly finished surface of the steel sheet by chemical polishing or electrolytic polishing. By chemical polishing or electrolytic polishing, if the surface roughness of the steel sheet was 0.5μm or less in terms of arithmetic average roughness Ra, preferably the iron loss oriented electrical steel sheet is remarkably improved.
[0117]
　As annealing separator, the alumina instead of magnesia can be used an annealing separator consisting mainly, which was then coated and dried, after drying, wound into a coil, finish annealing (secondary recrystallization) subjected to. The finish annealing can be produced oriented electrical steel sheet by suppressing the generation of inorganic mineral coating such as forsterite. After making, preferably smoothly finished surface of the steel sheet by chemical polishing or electrolytic polishing.
[0118]
　The forsterite or the like the surface of the inorganic mineral coating oriented electrical steel sheet to remove the, or on the surface of the grain-oriented electrical steel sheet which suppresses the generation of the film of an inorganic mineral such as forsterite, and phosphoric acid, phosphoric acid reaction a solution containing a compound containing a metal element forming the metal phosphide with (first solution) is applied to annealing to form an intermediate layer according to the present embodiment.
[0119]
　Metal source of the metal phosphide (i.e. a compound containing a metal element), for example chlorides, sulfates, carbonates, nitrates, phosphates, although single metals and the like, metal phosphides, good with steel in terms of ensuring the Do adhesion, Fe 3 P, Fe 2 P, and, one or more of FeP is preferred. Thus, a compound containing a metal element that produces a metal phosphide reacts with phosphoric acid, a compound containing Fe is preferred. Considering the reactivity with phosphoric acid, FeCl 3 is preferred. Incidentally, as a source of phosphorus in the metal phosphide, when an organic phosphate or phosphates, there is a risk that the metal phosphide amount is insufficient. Thus, the first solution should be intended to include phosphoric acid.
[0120]
　And phosphoric acid in the first solution to be applied, the ratio of the compound capable of reacting with the phosphoric acid containing a metal element forming the metal phosphide mass ratio 2: 1 to 1: 2, preferably 1: 1 to 1: adjusted to be 1.5. The ratio of the compound containing phosphoric acid and metal elements With the above-mentioned range, it is possible to sufficiently improve the adhesion of the insulating coating. If phosphoric acid is insufficient, the metal phosphide is not formed in the intermediate layer.
　The coating amount of the first solution is determined according to the thickness of the intermediate layer of interest. The amount itself of the metal phosphide in the intermediate layer is determined by the coating amount of the phosphoric acid, a compound containing a metal element. On the other hand, the thickness of the intermediate layer, as described below, the annealing temperature, annealing time, also determined by the dew point of the annealing atmosphere. Accordingly, by both the coating amount and the annealing conditions of the compound, so that the cross-sectional area ratio in the intermediate layer section of the metal phosphide is determined. For the above reason, it is necessary to determine in accordance with the application amount of the first solution in the intermediate layer thickness. For example, when the annealing under the condition that the thickness of the intermediate layer is 4nm is the coating amount of the first solution 0.03 ~ 4 mg / m 2 may be set to. When the thickness of the intermediate layer is annealed under conditions such that the 400nm little less than, the coating amount of the first solution 3 ~ 400 mg / m 2 may be set to. Note that the coating weight of the first solution, and phosphoric acid, a coating amount of the compound containing the metal element, the mass, such as water which is these solvents are not included in the coating amount of the first solution.
[0121]
　Annealing to form an intermediate layer according to the present embodiment, a temperature that is generated by the metal phosphide, may be held duration, in particular, but not limited to a particular temperature and holding time, generate and phosphoric acid, a metal phosphides in view of promoting the reaction of a compound containing a metal element, the annealing temperature is preferably 600 ~ 1150 ° C.. Compound containing an element for generating a metal phosphide FeCl 3 cases, the annealing temperature is preferably 700 ~ 1150 ° C.. Further, the annealing time is preferably 10 to 600 seconds.
[0122]
　Annealing atmosphere, as internal steel sheet is not oxidized, preferably a reducing atmosphere, in particular, nitrogen mixed with hydrogen. For example, the hydrogen: nitrogen 75%: 25%, dew point preferably an atmosphere of -20 ~ 2 ° C.. It may also be controlled by focusing the atmosphere oxidation potential. In this case, the annealing atmosphere, the oxygen partial pressure (P H2 O / P H2 : the ratio of steam partial pressure and hydrogen partial pressure) is preferably set to be in the range of 0.0016 to 0.0093.
[0123]
　Abundance of metal phosphide in the intermediate layer according to the present embodiment is 1 to 30% is preferred in section area ratio in the cross section of the intermediate layer according to the present embodiment. Preferably 5 to 25%. Intermediate layer according to the present embodiment, other metal phosphides, may contain α iron and / or iron silicate. α iron produced in the reduction of iron compounds, iron silicate is generated in a redox reaction with an oxidized silicon α iron or an iron compound.
[0124]
　Intermediate layer according to the present embodiment, other metal phosphides, as appropriate, may contain α iron and / or iron silicate, abundance sectional area ratio in the cross section of the intermediate layer according to the embodiment of these materials in 1-30% is preferred. Preferably 5 to 25%.
[0125]
　The thickness of the intermediate layer according to the present embodiment, the annealing temperature, holding time, and are prepared by adjusting the one or more dew point of the annealing atmosphere. The thickness of the intermediate layer according to the present embodiment, 4 ~ 400 nm is preferred. More preferably from 5 ~ 300nm. Thickness of the intermediate layer, the higher the annealing temperature, the longer the retention time, also becomes thicker the higher the dew point of the annealing atmosphere. The above temperature range, and in an atmosphere ranges, annealing temperature a regulator of thickness, holding time, and, with a dew point of one or more by adjusting the intermediate layer of the annealing atmosphere thickness predetermined prepared within the range.
[0126]
　Cooling the steel sheet after annealing, i.e., cooling of the intermediate layer according to the present embodiment, the degree of oxidation of the annealing atmosphere kept low, metal phosphides is performed not to chemical change. For example, the hydrogen: nitrogen 75%: 25%, dew point performed in an atmosphere of -50 ~ -20 ° C..
[0127]
　As a method for forming the intermediate layer according to the present embodiment may be used sol-gel method. For example, water - the silica gel were dissolved phosphorus compound in an alcohol solvent, was coated on the surface of the steel sheet in air, dried by heating to 200 ° C., after drying, in a reducing atmosphere, 1 minute 300 ~ 1000 ° C. held to be air-cooled.
[0128]
　Metal phosphides containing intermediate layer according to the present embodiment, and the particle size of α iron and / or iron silicate is preferably at least 1 nm. More preferably 3nm or more. On the other hand, the particle size is 2/3 of the layer thickness of the intermediate layer is preferably not more than according to the present embodiment. More or less half of the layer thickness of the intermediate layer according to the present embodiment preferably. Metal phosphides and, although factors is not clear at present that affect the particle size of the α iron and / or iron silicate, the higher the annealing temperature, and the longer the holding time, tended to increase . Also, metal phosphides The particle size, and the phosphoric acid in the first solution reacts with phosphoric acid to lower the ratio of the compound containing a metal element which forms a metal phosphide (i.e., phosphate amount for compound amount larger trend as the ratio of the smaller) was observed. By adjusting the one or more of these control factors preferred particle size can be obtained.
[0129]
　On the intermediate layer according to the present embodiment, by applying a second solution mainly composed of phosphate and colloidal silica, for example, baked at 850 ° C., to form a phosphate-based insulation coating. The method of the film thickness of the insulating film can be appropriately used a known method. For example, the thickness of the insulating coating by changing the coating amount of the second solution mainly composed of phosphate and colloidal silica, is controllable.
[0130]
　Coating adhesion of the insulating coating is evaluated by a bend adhesion test. After winding the oriented electrical steel sheet into a round bar having a diameter of 20 mm, flat rewind, measuring the area of ​​the insulating film is not peeled off from the steel plate, the ratio to the area of ​​the steel plate of the area: coating residual area ratio (% ) was calculated to evaluate the coating adhesion of the insulating coating.
Example
[0131]
　Next, a description will be given of an embodiment of the present invention, conditions in examples are an example of conditions adopted for confirming the workability and effects of the present invention, the present invention is, in this single condition example the present invention is not limited. The present invention does not depart from the gist of the present invention, as long as they achieve the object of the present invention, it is capable of adopting various conditions. The evaluation of the examples described below were carried out by the above-described evaluation methods.
[0132]
　(Example 1)
　Table 1 a silicon steel strip of composition shown by heating 60 minutes soaking at 1150 ° C. subjected to hot rolling to obtain a hot-rolled steel sheet 2.3mm thick. Then, this hot-rolled steel sheet, after holding for 200 seconds at 1120 ° C., immediately annealed to quench to 120 seconds held at 900 ° C., after pickling, subjected to cold rolling, the final thickness 0.23mm It was a cold-rolled steel sheet.
[0133]
[Table 1]

[0134]
　This cold-rolled steel sheet (hereinafter "steel"), a hydrogen partial pressure: the nitrogen partial pressure of 75%: 25% of the atmosphere, 850 ° C., was subjected to a decarburization annealing for holding 180 seconds. The steel sheet after decarburization annealing, hydrogen, nitrogen, a mixed atmosphere of ammonia, 750 ° C., subjected to nitriding annealing for holding 30 seconds, was adjusted nitrogen content of the steel sheet to 230 ppm.
[0135]
　Then, the steel sheet after nitriding annealing, the annealing separator consisting mainly of alumina was applied, then, in a mixed atmosphere of hydrogen and nitrogen, and heated to 1200 ° C. at a heating rate of 15 ° C. / time and finish-annealed performed, then, in a hydrogen atmosphere, subjected to purification annealing holding at 1200 ° C. 20 h, then allowed to cool, to produce a grain-oriented electrical steel sheet having a smooth surface. Arithmetic average roughness Ra of the grain-oriented electrical steel sheet was set to 0.21 [mu] m.
[0136]
　The smooth surface of the fabricated oriented electrical steel sheet, the aqueous solution containing the coating material shown in Table 2, the amount of coating material excluding water, was applied so that the coating amount shown in Table 2, the hydrogen: nitrogen 75%: 25%, in an atmosphere of dew point -20 ° C., 8 ° C. / sec and heated to 1000 ° C. at a heating rate of, after heating, the dew point of the atmosphere, 60 seconds holding and change immediately -5 ° C. did. The ratio of the compound containing phosphoric acid and metal elements in all of the coating material shown in Table 2, 2 in a weight ratio: 1 to 1: within 2 range. After holding, by changing the dew point of the atmosphere immediately -50 ° C., allowed to cool.
[0137]
　When Atsushi Nobori during the natural cooling, in order to suppress the oxidation reaction, it is set lower the dew point of the atmosphere. In particular, during natural cooling, holding lower the dew point of the atmosphere, suppressed the chemical change of the metal phosphide in the intermediate layer of silicon oxide mainly. During isothermal holding in order to form an intermediate layer of silicon oxide mainly held high the dew point of the atmosphere. In this manner, the surface of the grain-oriented electrical steel sheet, metal phosphides, and, to form an intermediate layer of silicon oxide mainly containing α iron and / or iron silicate. The layer thickness of the formed intermediate layer, shown in Table 2.
[0138]
[Table 2]

[0139]
　On the surface of the formed intermediate layer, magnesium phosphate, colloidal silica, an aqueous solution composed mainly of chromic anhydride was applied in a nitrogen atmosphere, and baked 30 seconds at 850 ° C., to form an insulating film.
[0140]
　Cut out test pieces from the grain-oriented electrical steel sheet with an insulating coating, as well as observing the cross section with transmission electron microscope, the thickness of the intermediate layer, and the intermediate layer was measured the total cross-sectional area of ​​the material to be contained. Energy dispersive X-ray spectroscopy, a material forming a main body of the intermediate layer, to identify the element ratio of materials intermediate layer contains, further, an electron beam diffraction method, to identify substances which intermediate layer contains. The results, shown in Table 2.
[0141]
　Next, the grain-oriented electrical steel sheet to form an insulating film, and was cut out 80 mm × 80 mm, wound around a round bar having a diameter of 20 mm, then, flat rewind, the area of ​​the insulating film is not peeled off from the steel plate measured and was calculated coating remaining area ratio. Sample coating remaining area ratio is 85% or more, has good adhesion, the sample is 90% or more were determined to have a better adhesion. The results are shown in Table 2.
[0142]
　Material forming a main body of the intermediate layer is a silicon oxide. The middle layer of the test piece A3, Fe 2 P, FeP, alpha iron, and, Fe 2 SiO 4 was present. These materials are coated product FeCl 3 Fe of, P coating material phosphoric acid, and is believed to have been formed by Si and O in the silicon oxide of the metallic intermediate layer. Note that (the average value of equivalent circle diameter) particle size of the metal phosphide of all specimens which are disclosed in Table 2 was the layer range of less than 2/3 of the thickness of 1nm or more and the intermediate layer.
[0143]
　Intermediate layer, phosphides, alpha iron, and, Fe 2 SiO 4 film remaining area of the test piece A1 containing no whereas 81%, the intermediate layer, Fe 2 P, FeP, alpha iron, and , Fe 2 SiO 4 film remaining area of the test piece A3 containing is 97%. Therefore, an intermediate layer of silicon oxide entity, when containing Fe phosphide, it is found that a remarkably improved film adhesion of the insulating coating.
[0144]
　An intermediate layer of silicon oxide principal, Co 2 P, Ni 2 P, or, Cu 3 film remaining area of the test piece A4 ~ A6 containing P is below 90%, Co 2 P, Ni 2 P, and, Cu 3 P will, Fe 2 as the P and FeP, it is understood that do not contribute to the improvement of the coating adhesion of the insulating coating. However, compared to test piece A2, the coating adhesion is improved, the intermediate layer is Co 2 P, Ni 2 P, and, Cu 3 also those containing P, an invention example.
[0145]
　(Example 2)
　In the same manner as in Example 1 to prepare a grain-oriented electrical steel sheet having a smooth surface. On the surface of the grain oriented electrical steel sheet, the aqueous solution containing the coating material shown in Table 3, the amount of coating material excluding water, was applied so that the coating amount shown in Table 3, the hydrogen: nitrogen 75%: 25%, dew point in an atmosphere of -20 ° C., was heated to 1150 ° C. at a heating rate of 8 ° C. / sec. The ratio of the compound containing phosphoric acid and metal elements in all of the coating material shown in Table 3, 2 in a weight ratio: 1 to 1: within 2 range.
[0146]
　After heating, the dew point of the atmosphere immediately changed to -3 ° C., and held retention time shown in Table 3, after holding, by changing the dew point of the atmosphere immediately -30 ° C., the intermediate layer on the smooth surface of the steel sheet to form, after the formation was natural cooling.
[0147]
　As in Example 1, an insulating film on said intermediate layer, and a material forming a main body of the intermediate layer, to identify substances which intermediate layer contains, further, the total cross-sectional area of ​​the material, and the insulating It was measured coating remaining area ratio of the film. The results are shown in Table 3. Note that (the average value of equivalent circle diameter) particle size of the metal phosphide of all specimens which are disclosed in Table 3 was in the layer range of less than 2/3 of the thickness of 1nm or more and the intermediate layer.
[0148]
[table 3]

[0149]
　Material forming a main body of the intermediate layer was silicon oxide. Coating the residual area ratio of thickness 583nm and a thick specimen A11 of the intermediate layer while 90% or less, the film residual area ratio of thickness less specimen A7 ~ 400 nm of the intermediate layer A10 is more than 90% it is. Thus, the thickness of the intermediate layer is preferably 400nm or less. However, the test piece A11 thickness of the intermediate layer is 400nm greater also, so had a coating remaining area of ​​greater than 85% is acceptance criterion, it is determined that the invention examples.
[0150]
　(Example 3)
　In the same manner as in Example 1 to prepare a grain-oriented electrical steel sheet having a smooth surface. On the surface of the grain oriented electrical steel sheet, the aqueous solution containing the coating material shown in Table 4, the amount of coating material excluding water, was applied so that the coating amount shown in Table 4, the hydrogen: nitrogen 75%: 25%, dew point in an atmosphere of -20 ° C., was heated to 700 ° C. at a heating rate of 6 ° C. / sec. The ratio of the compound containing phosphoric acid and metal elements in all of the coating material shown in Table 4, 2 in a weight ratio: 1 to 1: within 2 range.
[0151]
　After heating, the dew point of the atmosphere, and change immediately 1 ° C., and held retention time shown in Table 4, after the holding, by changing the dew point of the atmosphere immediately -40 ° C., the intermediate layer smooth surface of the steel sheet It formed, after the formation was natural cooling.
[0152]
　In the same manner as in Example 1, an insulating film on said intermediate layer, and a material forming a main body of the intermediate layer, to identify substances which intermediate layer contains, further, the total cross-sectional area of ​​the material, and, It was measured coating remaining area of ​​the insulating film. The results are shown in Table 4. Note that (the average value of equivalent circle diameter) particle size of the metal phosphide of all specimens which are disclosed in Table 4 was in the layer range of less than 2/3 of the thickness of 1nm or more and the intermediate layer.
[0153]
[Table 4]

[0154]
　Material forming a main body of the intermediate layer was silicon oxide. Material intermediate layer contains is, Fe 2 P, Fe 3 P, and / or a FeP, alpha iron and Fe 2 SiO 4 was not detected. This is because the annealing holding temperature for forming the intermediate layer 700 ° C. and lower, alpha iron and Fe 2 SiO 4 is considered that did not generate.
[0155]
　Coating the residual area of ​​the test piece A12 below the thickness of the intermediate layer is 4nm whereas less than 90%, the coating remaining area of ​​the test piece A13 ~ A15 of the thickness of the intermediate layer 8 ~ 21 nm 90% or more. Thus, the thickness of the intermediate layer is 4nm or more, it can be seen that excellent grain-oriented electrical steel sheet with a coating adhesion can be obtained.
[0156]
　Further, while the film residual area ratio of the total cross-sectional area ratio of 0.6% of the samples A16 substances present in the intermediate layer is less than 90%, the total cross-sectional area ratio of material present in the intermediate layer is 1 If at least percent of the samples A13 ~ A15, film residual area ratio became 90%. Thus, the total cross-sectional area ratio of material present in the intermediate layer is 1% or more, it can be seen that excellent grain-oriented electrical steel sheet by adhesion can be obtained.
[0157]
　(Example 4)
　Table subjected silicon steel strip showing the component composition to 1 (slab) to 60 minutes soaking in hot rolled at 1150 ° C., it was hot-rolled steel sheet 2.3mm thick. Then, this hot-rolled steel sheet, after holding for 200 seconds at 1120 ° C., immediately annealed to quench held in 120 seconds 900 ° C., after pickling, subjected to cold rolling, final sheet thickness 0.27mm It was a cold-rolled steel sheet.
[0158]
　This cold-rolled steel sheet (hereinafter "steel"), hydrogen: nitrogen 75%: 25% of the atmosphere, were subjected to decarburization annealing for holding 180 seconds at 850 ° C.. The steel sheet after decarburization annealing, hydrogen, nitrogen, in a mixed atmosphere of ammonia is subjected to a nitriding annealing for holding 30 seconds at 750 ° C., was adjusted nitrogen content of the steel sheet to 230 ppm.
[0159]
　Then, the steel sheet after nitriding annealing, the annealing separator composed mainly of magnesia was coated, then in a mixed atmosphere of hydrogen and nitrogen, finish annealing was heated to 1200 ° C. at a heating rate of 15 ° C. / Time alms, then in a hydrogen atmosphere, and held at 1200 ° C. 20 hours subjected to purification annealing in, then naturally cooled steel sheet after purification annealing.
[0160]
　Is formed on the surface of the steel sheet to remove the forsterite film composed mainly of forsterite by pickling, after removal, it is subjected to electrolytic polishing, to produce a grain-oriented electrical steel sheet having a smooth surface. Arithmetic average roughness Ra of the grain-oriented electrical steel sheet was set to 0.14 .mu.m.
[0161]
　On the surface of the grain oriented electrical steel sheet, the aqueous solution containing the coating material shown in Table 5, the amount of coating material excluding water, was applied so that the coating amount shown in Table 5, the hydrogen: nitrogen 75%: 25%, in an atmosphere of dew point -20 ° C., then heated to 800 ° C. at a heating rate of 6 ° C. / sec, after heating, by changing the dew point of the atmosphere immediately -1 ° C., held shown in Table 5 and retention time, after holding, by changing the dew point of the atmosphere immediately -50 ° C., the intermediate layer is formed on a smooth surface, after formation, was naturally cooled. The ratio of the compound containing phosphoric acid and metal elements in all of the coating material shown in Table 5, 2 in a weight ratio: 1 to 1: within 2 range.
[0162]
　As in Example 1, an insulating film on said intermediate layer, and a material forming a main body of the intermediate layer, to identify substances which intermediate layer contains, further, the total cross-sectional area of ​​the material, and the insulating It was measured coating remaining area ratio of the film. The results are shown in Table 5. Note that (the average value of equivalent circle diameter) particle size of the metal phosphide of all specimens which are disclosed in Table 5 were within the layer range of less than 2/3 of the thickness of 1nm or more and the intermediate layer.
[0163]
[table 5]

[0164]
　Material forming a main body of the intermediate layer was silicon oxide. Coating the residual area ratio of the sum of material intermediate layer contains cross area ratio of 63% of the specimens A17 whereas less than 90%, the test the total cross-sectional area of ​​the material that the intermediate layer contains the following 30% coating the residual area ratio piece A18 ~ A20 are 90% or more. Thus, the total cross-sectional area of ​​the material which the intermediate layer contains is less than 30%, it can be seen that excellent grain-oriented electrical steel sheet with a coating adhesion can be obtained.
Industrial Applicability
[0165]
　As described above, according to the present invention, the entire surface of the steel sheet, metal phosphides, and other, as appropriate, contain α iron and / or iron silicate, ensure and excellent coating adhesion of the insulating coating without unevenness oriented electrical steel sheet comprising an intermediate layer of silicon oxide entities that may be, and its manufacturing method can be provided. Accordingly, the present invention has high applicability in the electromagnetic steel sheet production and use industries.
DESCRIPTION OF SYMBOLS
[0166]
　1 steel plate
　2 forsterite film
　3 insulating film
　4 intermediate layer
　5 metal phosphides

WE claims

[Requested item 1]
　And the steel sheet,
　an intermediate layer containing Si and O arranged on the steel sheet,
　the insulating film disposed on the intermediate layer
a grain-oriented electrical steel sheet having the
　said intermediate layer is a metal phosphides containing, and
　the and the layer thickness of the intermediate layer is 4nm or more,
　the abundance of the metal phosphide, the 1 to 30% cross-sectional area ratio in the cross section of the intermediate layer
oriented electrical steel sheet, characterized in that.
[Requested item 2]
　The metal phosphide, Fe 3 P, Fe 2 P, and the directional electromagnetic steel sheet according to claim 1, characterized in that one or more of Fe phosphide FeP.
[Requested item 3]
　The intermediate layer, oriented electrical steel sheet according to claim 1 or 2, characterized in that it contains α iron and / or iron silicate in addition to the metal phosphide.
[Requested item 4]
　The metal phosphide, and, alpha abundance of total iron and / or iron silicate is directionality of claim 3, characterized in that 1 to 30% cross-sectional area ratio in the cross section of the intermediate layer electromagnetic steel sheet.
[Requested item 5]
　Oriented electrical steel sheet according to any one of claims 1 to 4, characterized in that the layer thickness of the intermediate layer is less than 400 nm.
[Requested item 6]
　Oriented electrical steel sheet according to any one of claims 1 to 5, the thickness of the insulating film is characterized in that it is a 0.1 ~ 10 [mu] m.
[Requested item 7]
　Oriented electrical steel sheet according to any one of claims 1 to 6, wherein the surface roughness of the steel sheet is 0.5μm or less in terms of arithmetic average roughness Ra.
[Requested item 8]
　A method of manufacturing a grain-oriented electrical steel sheet according to any one of claims 1 to 7,
　and obtaining a hot-rolled steel sheet and steel strip by hot rolling,
　the hot-rolled steel sheet was cold rolled obtaining a cold rolled steel sheet,
　the cold-rolled steel sheet to decarburization annealing, forming an oxide layer on the surface of the cold-rolled steel sheet,
　an annealing separating agent on the surface of the cold rolled steel sheet having said oxide layer a step of applying,
　after drying the annealing separator, the steps of winding the cold-rolled steel sheet,
　a step of annealing finish wound said cold-rolled steel sheet,
　a step of applying a first solution,
　wherein the first solution further annealing the cold-rolled steel sheet coated, forming an intermediate layer containing a metal phosphide,
　a step of applying a second solution to the surface of the intermediate layer,
　the second a step of baking said cold-rolled steel sheet second solution is applied
with a
　said first solution, phosphoric acid And a metal compound, the mass ratio of the metal compound and the phosphoric acid is 2: 1 to 1: 2,
　in annealing for forming the intermediate layer, the annealing temperature of 600 ~ 1150 ° C., the annealing time and 10 to 600 seconds, the dew point in the annealing atmosphere was -20 ~ 2 ° C., the 75% ratio of hydrogen amount and the amount of nitrogen in the annealing atmosphere of a 25%
　abundance of the metal phosphide, the intermediate layer controlling the coating amount of the first solution to a 1 to 30% cross-sectional area ratio in the cross section
Method for producing a grain-oriented electrical steel sheet, characterized in that.
[Requested item 9]
　Moreover, prior to applying the first solution, said comprising the step of removing inorganic mineral coating caused by finish annealing,
　the annealing separator is mainly composed of magnesia
to claim 8, characterized in that method for producing oriented electrical steel sheet according.
[Requested item 10]
　Furthermore, prior to the cold rolling method for producing a grain-oriented electrical steel sheet according to claim 8 or 9, characterized in that it comprises a step of annealing said hot-rolled steel sheet.