The present invention relates to an excellent grain-oriented electrical steel sheet to film adhesion. In particular, the present invention relates to oriented electrical steel sheet excellent in film adhesion of the insulating film even without forsterite coating.
　This application, on July 13, 2017, claiming priority on Japanese Patent Application No. 2017-137416 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. The magnetic properties, 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 is advantageous in terms of transformer device configuration, and 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 it is necessary to control the texture to <100> crystal orientation axes are aligned in the rolling direction (Goss orientation). To integrate the crystal orientation Goss orientation, AlN, MnS, and inhibitors of such MnSe by finely precipitated in the steel, it is possible to control the secondary recrystallization, usually performed.
[0004]
　The iron loss, when excited core with alternating magnetic field, a power loss consumed as heat energy. From the viewpoint of energy saving, iron loss, it is required as low as possible. The level of the iron loss, magnetic susceptibility, the plate thickness, film tension, the amount of impurities, electrical resistivity, grain size, domain size and the like is affected. Relates electromagnetic steel, even in currently various techniques have been developed to enhance the energy efficiency, 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 base steel sheet surface. Usually, in the grain-oriented electrical steel sheet, as shown in FIG. 1, Mg on the base steel sheet 1 2 SiO 4 forsterite film 2 composed mainly of (forsterite) Forsterite film and the insulating coating, the base material steel plate surface electrically insulating and has a function of reducing the iron loss by imparting a tension to the base steel sheet. Note that the forsterite coating Mg 2 SiO 4 in addition, impurities or additives contained in the base steel sheet and annealing separator, and their reaction products are also included in the trace.
[0006]
　Insulating coating, in order to exert the insulation and the required tension insulating coating must not peeled from the electromagnetic steel sheet, therefore, a high film adhesion is required for the insulating film. However, increasing both the tension and the film adhesion to impart to the base steel sheet at the same time is not easy. Even in the current, research and development to enhance both of them at the same time is being continued incessantly.
[0007]
　Oriented electrical steel sheet is usually produced by the following procedure. 2.0 to 4.0 mass% content for silicon steel slab Si, and hot rolled, annealed if necessary after hot rolling, then between one or more times of cold sandwiching the intermediate annealing subjected to rolling, 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.
[0008]
　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, the crystal grains were integrated in the Goss orientation, further, SiO oxide layer and MgO in the annealing separator 2 and a (silica) 2 SiO 4 to form a forsterite coating inorganic mainly of.
[0009]
　Then subjected to purification annealing in a steel sheet having a forsterite film, it is removed by diffusing impurities of the base material steel plate in outward. Further, after performing flattening annealing the steel sheet, the steel sheet surface with a forsterite film to form an insulating film and baked by applying a solution mainly composed of phosphate and colloidal silica. At this time, between the base material steel plate is crystalline and the insulating film is substantially amorphous, tension is applied from the difference in the thermal expansion coefficient.
[0010]
　Mg 2 SiO 4 interface between the forsterite film mainly composed of (in FIG. 1 "2") and steel (in FIG. 1 "1") is usually no uneven uneven (Fig. 1, reference ). The interface of uneven shape, is offset slightly the iron loss reducing effect by tension. Therefore the interface is it if iron loss is smoothed is reduced, to date, the development such as the following have been carried out.
[0011]
　Patent Document 1, to remove forsterite films 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, there is a case where the base steel sheet surface hard insulating coating adhered.
[0012]
　Therefore, in order to improve the film adhesion of the insulation coating on smooth finished steel sheet surface, as shown in FIG. 2, the intermediate layer 4 between the base steel sheet and the insulating film (or undercoat) to form a was suggested. Disclosed in Patent Document 2, the base film formed by coating an aqueous solution of phosphoric acid or alkali metal silicate may be effective in film adhesion. As a further method which is effective, in Patent Document 3, before the formation of the insulating film, 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 ing.
[0013]
　Furthermore, Patent Document 4, before the formation of the insulating film, the base material steel plate surface, 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 composed of boric acid compound and an alumina sol, a method of forming an outer oxide layer of amorphous, such as silica layer as the intermediate layer is disclosed ing.
[0014]
　These external oxidation type silica layer is formed as an intermediate layer in the base steel sheet surface, and functions as a base for smooth interface, the improvement of the coating adhesion of the insulating film, 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.
[0015]
　Patent Document 6, the base material steel plate was smooth surfaces, 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 of (Kuneberaito) to form an intermediate layer of crystalline, a method of forming an insulating film is disclosed thereon.
[0016]
　However, the base steel sheet surface, Fe 2 SiO 4 or (Fe, Mn) 2 SiO 4 in an oxidizing atmosphere to form a, by oxidation of Si in the base steel sheet surface layer, SiO 2 oxides such is precipitated put away, there is a case in which the iron loss characteristics are degraded.
[0017]
　Further, Fe intermediate layer 2 SiO 4 and (Fe, Mn) 2 SiO 4 is crystalline, whereas, the insulating film formed in a solution mainly composed of phosphate and colloidal silica is largely amorphous it is. An intermediate layer of crystalline and substantially amorphous insulating film in some cases the adhesion is not stable.
[0018]
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 If there is a.
[0019]
　Patent Document 7, a smooth base steel sheet surface, the sol - gel method, an intermediate layer, to form a 0.1 ~ 0.5 [mu] m thick gel film, on the intermediate layer, forming an insulating film how to have been disclosed.
[0020]
　However, the deposition conditions disclosed in Patent Document 7, the general sol - in the range of gel method, may not be firmly secured to film adhesion.
[0021]
　Patent Document 8, a smooth base material steel plate surface by anodic electrolysis in the aqueous solution of silicate, to form a siliceous film as an intermediate layer, then, a method of forming an insulating film are disclosed. Patent Document 9, a smooth base steel sheet surface, 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, the above, the silica layer is present, further, on the electromagnetic steel sheet insulating coating is present is disclosed.
[0022]
　By forming an intermediate layer such as these, can improve the film adhesion, the newly requires large-scale facilities such as electrolytic treatment facilities and dry coating, it is difficult to secure the site, and there are cases where the production cost is increased.
[0023]
　Patent Document 10, a smooth base steel sheet surface, the film thickness is 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 a method of forming an insulating film on the intermediate layer is disclosed.
[0024]
　Patent Document 11, a smooth base steel sheet surface, the film thickness in the 0.005 ~ 1 [mu] m, containing 1 to 70% of metallic iron or iron-containing oxides in a volume fraction, the silicon oxide glassy to form an intermediate layer mainly, a method of forming an insulating film on the intermediate layer is disclosed.
[0025]
　In Patent Document 12, a smooth base steel sheet surface, the film thickness is at 2 ~ 500 nm, the metallic oxide (Si-Mn-Cr oxide, Si-Mn-Cr-Al -Ti oxides, Fe oxide), containing 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 film on the intermediate layer is disclosed.
[0026]
　Thus, SiO 2 intermediate layer entity, metallic iron, iron-containing oxides or improved when containing a metal-based oxide, although film adhesion of the insulating film is improved to some extent, further the industrial There has been expected.
[0027]
　On the other hand, in Patent Documents 13-15, in the case of forming an insulating film mainly containing acidic organic resin which does not substantially contain a chromium steel sheet, between the steel sheet and the insulating film, a phosphorus compound layer (FePO 4 , Fe 3 (PO 4 ) 2 , FeHPO 4 , Fe (H 2 PO 4 ) 2 , Zn 2 Fe (PO 4 ) 2 , Zn 3 (PO 4 ) 2 and, a layer consisting of a hydrate, or, mg, Ca 2 may be a layer made of, Al phosphate, thickness to form a 10 ~ 200 nm), a technique for improving the adhesion and appearance of the insulating film are disclosed. However, in these above techniques, there is a case where the insulating film is peeled off locally.
CITATION
Patent Document
[0028]
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 2003-313644 JP
Patent Document 11: Japanese Patent 2003-171773 JP
Patent Document 12: Japanese JP 2002-348643 JP
Patent Document 13: Japanese Patent 2001-220683 JP
Patent Document 14: Japanese Patent 2003-193251 Patent Publication No. Distribution
Patent Document 15: Japanese Patent 2003-193252 JP
Summary of the Invention
Problems that the Invention is to Solve
[0029]
　Usually, the film structure of the grain-oriented electrical steel sheet having no forsterite coating, "the base steel sheet - an intermediate layer of silicon oxide mainly - insulating film" is a three-layer structure of the form between the base steel sheet and the insulating film is the macroscopic uniform smooth (Fig. 2, reference). However, also in excellent insulating film on a conventional film adhesion, the insulating coating is peeled off locally.
[0030]
　This is because, in the coating structure of the three-layer structure, an intermediate layer of silicon oxide mainly (hereinafter, simply referred to as "intermediate layer".) Is thin point is present locally, the film adhesion at this point sex is reduced, presumably insulating coating is peeled off. Such reduction in localized film adhesion is, because it affects the tension applied to the base steel sheet also affects the iron loss.
[0031]
　Accordingly, the present invention provides an insulating film, on the entire surface of the intermediate layer of silicon oxide mainly formed as plaque adhesion between the intermediate layer does not occur, grossly, film adhesion to the electromagnetic steel sheet insulating coating it is an object to increase the resistance. That is, the present invention is intended to even without forsterite coating provides excellent oriented electrical steel sheet film adhesion of the insulating film.
Means for Solving the Problems
[0032]
　In the prior art, in order to uniform the film adhesion of the insulating film, the smooth finished base steel sheet surface, an intermediate layer of silicon oxide mainly be more uniform and smooth surface. However, in practice, as described above, the film adhesion of the insulating film formed by baking by applying a solution mainly composed of phosphate and colloidal silica has spots, the insulating coating is peeled off locally .
[0033]
　The present inventors have found that a technique of solving the above problems, intensive studies without concern technical common sense.
[0034]
　As a result, the lower region of the insulating film, in contact with the intermediate layer of silicon oxide mainly to form a crystalline phosphide-containing layer containing a crystalline phosphide, suppress the occurrence of film adhesion plaques of the insulation coating it can be, as a result, while properly maintaining the insulating property of the insulating film, found that it is possible to improve the film adhesion to the electrical steel sheet insulating coating.
[0035]
　The gist of the present invention is as follows.
[0036]
　(1) grain-oriented electrical steel sheet according to an embodiment of the present invention will become a base steel sheet, and an intermediate layer disposed in contact on the base steel sheet, and the intermediate layer in contact with arranged that in the uppermost surface a grain-oriented electrical steel sheet having an insulating film, when the cutting direction is viewed in cutting plane becomes parallel to the thickness direction, wherein the insulating film is, in a region in contact with on the intermediate layer, containing a crystalline phosphides a crystalline phosphide-containing layer.
[0037]
　(2) In the oriented electrical steel sheet according to (1), wherein when viewed in cutting plane, the average thickness of the crystalline phosphide-containing layer, the average thickness of at least 1/10 and of the insulating film it may be less than half.
[0038]
　(3) In the oriented electrical steel sheet according to (1) or (2), wherein when viewed in cutting plane, wherein the crystalline phosphide area fraction is an average of 5 to the on crystalline phosphides containing layer it may be 50%.
[0039]
　(4) In the oriented electrical steel sheet according to any one of (1) to (3), when viewed in the cutting plane, met 5 ~ 300 nm circle equivalent diameter by the average of the crystalline phosphides it may be.
[0040]
　(5) In the oriented electrical steel sheet according to any one of (1) to (4), the crystalline phosphide, as chemical components, Fe, Cr, P, and O in the total of 70 atomic% or more and containing 100 atomic% or less, Si may be limited to 10 atomic% or less.
[0041]
　(6) In the oriented electrical steel sheet according to any one of (1) to (5), as a crystalline phosphide, FeP, Fe 2 P, Fe 3 P, FeP 2 or Fe, 2 P 2 O 7 may include at least one.
[0042]
　(7) In the oriented electrical steel sheet according to any one of (1) to (6), as a crystalline phosphide, (Fe, Cr) P, (Fe, Cr) 2 P, (Fe, Cr ) 3 P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 , may include at least one.
The invention's effect
[0043]
　According to this aspect of the present invention, grain-oriented electrical steel sheet having an insulation coating unevenness is not in film adhesion, i.e., even without forsterite coating provides excellent oriented electrical steel sheet film adhesion of the insulating film be able to.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044]
It is a cross-sectional view schematically showing the FIG. 1 coating structure of a conventional grain-oriented electrical steel sheet.
It is a cross-sectional view schematically showing the FIG. 2 another film structure of the conventional oriented electrical steel sheet.
3 is a schematic sectional view showing a film structure of the grain-oriented electrical steel sheet according to an embodiment of the present invention.
DESCRIPTION OF THE INVENTION
[0045]
　The following describes in detail preferred embodiments of the present invention. However, the present invention is not limited only to the configuration disclosed in this embodiment, and various modifications are possible without departing from the scope of the present invention. In addition, the numerical limitation range below the lower limit value and the upper limit value is included in the range. A number indicating the "super" or "less than", the value is not included in the numerical range.
[0046]
　Excellent oriented electrical steel sheet coating adhesion according to the present embodiment (hereinafter sometimes referred to as "the present invention electrical steel sheet".) Has no forsterite coating on the surface of the base steel sheet, on the surface of the base material steel plate an intermediate layer of silicon oxide mainly in a grain-oriented electrical steel sheet having an insulation coating composed mainly of phosphate and colloidal silica onto the intermediate layer,
　the lower region of the insulating film, to the intermediate layer contact, a crystalline phosphide-containing layer containing a crystalline phosphide.
[0047]
　Specifically, oriented electrical steel sheet according to the present embodiment includes a base steel sheet, and the base steel sheet on contact with arranged intermediate layer, and this contact intermediate layer disposed is to the outermost surface an oriented electrical steel sheet having an insulating coating,
　when the cutting direction is cut surface parallel to the thickness direction (specifically, the thickness direction and parallel to and rolling direction and a cutting plane perpendicular) viewed in the insulating film but the region in contact with the intermediate layer, a crystalline phosphide-containing layer containing a crystalline phosphide.
[0048]
　Here, the not-oriented electrical steel sheets forsterite film, the grain-oriented electrical steel sheet produced by removing the forsterite coating after manufacture, or is the oriented electrical steel sheet produced by suppressing the formation of forsterite coating .
[0049]
　The following describes the present invention electrical steel sheet.
[0050]
　In the prior art, the annealing in an atmosphere having a controlled dew point by performing the (thermal oxidation process), or the like to form an intermediate layer of silicon oxide mainly on the surface of the base steel sheet against the base steel sheet having no forsterite coating, on the intermediate layer insulating film forming solution baked annealing is applied to form an insulating film. The cross-sectional structure of a conventional electromagnetic steel sheet, as shown in FIG. 2 a three-layer structure of "insulating film - - intermediate layer base steel sheet". 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 base steel sheet, each layer is easily peeled off.
[0051]
　Accordingly, the present inventors have - focused on layers of "insulating film interlayer", by adding another extra layer on the interlayer while maintaining the tension applied to the base material steel plate, the adhesion of the interlayer the idea that it would be able to increase the sex, were investigated can be added layer as described below.
[0052]
　Additional possible layer was examined layers having components such as familiar to both the insulating coating and the base steel sheet. That is, the main component is the same as the insulating film, in this, primarily, P, O, and / or to consider admixing a compound containing Fe. Also, including Cr is a property similar to Fe, it was studied by mixing a compound containing P, O, Fe, and Cr.
[0053]
　For example, a compound to be mixed, a chemical component, Fe, Cr, P, and O is the total content of 70 at% or more and 100 atomic percent, were investigated compounds Si is limited to 10 atomic% or less .
[0054]
　Specifically, as the compound to be mixed, Fe 3 P, Fe 2 P, FeP, FeP 2 , Fe 2 P 2 O 7 were examined crystalline phosphide such. Furthermore, including Cr is a property similar to Fe, is a compound in which a part is replaced with Cr of Fe, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , (Fe, Cr) 2 P 2 O 7 were also examined becomes crystalline phosphide.
[0055]
　Based on the above study results, the coating solution mainly composed of phosphate and colloidal silica for forming the insulating film, to prepare a solution of a mixture of crystalline phosphide above. The solution was a crystalline phosphide-containing layer forming solution.
[0056]
　Thermal oxidation treatment (annealing in an atmosphere having a controlled dew point) or the like performed to form an intermediate layer of silicon oxide mainly on the surface of the base steel sheet against the base steel sheet having no forsterite coating, the intermediate layer over, baked by applying a crystalline phosphide-containing layer forming solution further baked by applying an insulating film-forming solution to form an insulating film. Thus was evaluated film adhesion of the electromagnetic steel sheet was prepared.
[0057]
　The above investigation, the lower region of the insulating film, in contact with the intermediate layer of silicon oxide mainly the crystallinity phosphide is generated by concentrated crystalline phosphide-containing layer is formed, coating of the insulating film it was found that adhesion is remarkably improved.
[0058]
　3, a film structure of the present invention electrical steel sheet schematically showing. Sectional structure of the present invention electrical steel sheet, as shown in FIG. 3, "the base steel sheet 1 intermediate layer 4 crystalline crystalline phosphide-containing layer containing a phosphide 5 6- insulating film 3 'that four-layer structure it is.
[0059]
　That is, in the lower region of the insulating film, in contact with the intermediate layer of silicon oxide mainly crystalline phosphide-containing layer is formed, the cross-sectional structure has a substantially four-layer structure.
[0060]
　The crystalline phosphide-containing layer 6 and the insulating film 3, strictly different. However, the parent phase of crystalline phosphide-containing layer 6 is the same as components of the insulating film 3, the crystalline phosphide-containing layer 6 and the insulating film 3 are similar. The crystalline phosphide-containing layer 6 and the insulating film 3, there is a difference in whether or not containing crystalline phosphide 5.
[0061]
　Hereinafter, each layer will be described of the present invention electrical steel sheet.
[0062]
　The base steel sheet
　in the above-mentioned four-layer structure, the base material steel plate as the base material has a texture having a crystal orientation is controlled to the Goss orientation. Surface roughness of the base steel sheet is not particularly limited, in that by applying a large tension to the base steel sheet reduced iron loss, preferably 0.5μm or less in arithmetic average roughness (Ra), 0. more preferably equal to or less than 3μm. The lower limit of the arithmetic mean roughness of the base material steel plate (Ra) is not particularly limited, the lower limit may be 0.1μm since the iron loss improvement effect comes saturated with 0.1μm or less.
[0063]
　Also the thickness of the base material steel plate is not particularly limited, in order to further reduce the iron loss, the thickness is preferably 0.35mm or less in average, more preferably not more than 0.30 mm. The lower limit of the thickness of the base material steel plate is not particularly limited, from the viewpoint of production equipment and cost, it may be 0.10 mm.
[0064]
　The base steel sheet, since it contains a high concentration of Si (e.g., 0.80 to 4.00 wt%), a strong chemical affinity is expressed between the intermediate layer of silicon oxide mainly intermediate layer and the base and wood steel sheet firmly adhered.
[0065]
　An intermediate layer of silicon oxide mainly
　in the four-layer structure, the intermediate layer is disposed over and in contact with the base steel sheet has a function of adhering the insulating film includes a base steel sheet crystalline phosphide-containing layer.
[0066]
　Silicon oxide forming a main body of the intermediate layer, SiOx (x = 1.0 ~ 2.0) is preferable. If SiOx (x = 1.5 ~ 2.0), since the silicon oxide is more stable, more preferred. If sufficiently performed oxidation annealing in forming a silicon oxide on the surface of the base material steel plate, it is possible to form the SiOx (x ≒ 2.0).
[0067]
　Normal conditions (atmospheric gas: 20 ~ 80% N 2 + 80 ~ 20% H 2 , dew point: -20 ~ 2 ° C., annealing temperature: 600 ~ 1150 ° C., annealing time: 10 to 600 seconds) by performing the oxidation annealing in , silicon oxide, since the remains amorphous, has a high strength to withstand thermal stresses and elasticity increases, the thermal stress can be easily relaxed, the intermediate layer of dense material of the base material steel plate it can be formed on the surface.
[0068]
　If the thickness of the intermediate layer is thin, the thermal stress relaxation effect is not exhibited sufficiently, the thickness of the intermediate layer is more than 2nm in average are preferable. More preferably 5nm or more. On the other hand, if the thickness of the intermediate layer is thick, it becomes uneven thickness, and since the defects of voids and cracks in the layer occurs, the thickness of the intermediate layer is preferably 400nm or less on average. More preferably 300nm or less.
[0069]
　Insulating film
　in the four-layer structure, the insulating film is located on the outermost surface, phosphate and colloidal silica (SiO 2 as an insulating film of vitreous formed by baking by applying a solution mainly composed of).
[0070]
　This insulating coating, which can impart a high surface tension in the base steel sheet, the insulating film of the present invention electrical steel sheet has, in its lower region, in contact with the intermediate layer of silicon oxide mainly containing crystalline phosphides since a crystalline phosphide-containing layer (described later) (see FIG. 3,), film adhesion of the insulating film is remarkably improved, the base material steel plate, is possible to impart a higher surface tension it can.
[0071]
　It will be described later forming method of the insulating film containing a crystalline phosphide-containing layer.
[0072]
　Although in the crystalline phosphides are also conductive field, since crystalline phosphide in the upper region of the insulating film (region excluding the crystalline phosphide-containing layer) is not present, the insulating property of the insulating coating satisfactorily It is maintained at.
[0073]
　When the thickness of the insulating film (including a crystalline phosphide-containing layer) is less than 0.1 [mu] m, the thickness of the crystalline phosphides containing layer is thin, without improving the film adhesion of the insulating film, a steel plate since it is difficult to impart the desired surface tension, preferably above 0.1μm in average thickness. More preferably 0.5μm or more.
[0074]
　On the other hand, if the thickness of the insulating film (including a crystalline phosphide-containing layer) is more than 10 [mu] m, the formation step of the insulating film, there is a possibility that cracks occur in the insulating film, 10 [mu] m or less thick on average preferable. More preferably 5μm or less.
[0075]
　Incidentally, if necessary, laser, plasma, mechanical methods, etching, and other methods, or make local micro strain may be subjected to magnetic domain refining treatment or to form a local groove.
[0076]
　In consideration of recent environmental issues, the insulating coating, in particular in the upper region of the insulating film (region excluding the crystalline phosphide-containing layer), as chemical components, the average Cr concentration less than 0.10 atomic% limit it is preferable to be, it is further preferable to be limited to less than 0.05 atomic%.
[0077]
　Crystalline phosphide-containing layer
　in the four-layer structure, crystalline phosphides containing layer is present in the lower region of the insulating film, it is disposed in contact on an intermediate layer of silicon oxide mainly and an upper region of the insulating film ( It arranged neighboring and excluding the crystalline phosphide-containing layer region) (Fig. 3, reference). Crystalline phosphide-containing layer, the insulating film is important to ensure and excellent film adhesion without unevenness.
[0078]
　The lower region of the insulating film, the crystalline phosphide-containing layer in contact with the intermediate layer of silicon oxide mainly exists, why film adhesion of the insulating film is remarkably improved is not clear, it is "amorphous When phosphide crystalline in the mother phase of the crystalline phosphide-containing layer (insulating film and the same component) is present, increasing the overall elasticity of the crystalline phosphide-containing layer, even under bending stress, intermediate layer as the insulating coating and the accumulated stress relaxation, there is no unevenness in film adhesion of the insulating film, the insulating film is considered to be difficult to peel. "
[0079]
　The thickness of the crystalline phosphide-containing layer is greater than half the thickness of the insulating film containing a crystalline phosphide-containing layer, in order to impart tension to the base material steel plate by the insulating film is relatively decreased , there is a possibility that iron loss characteristics deteriorate, further, there is a possibility that the insulating property of the insulating film is lowered. Therefore, the thickness of the crystalline phosphides containing layer, on average, less than half the preferred thickness of the insulating film containing a crystalline phosphide-containing layer. More preferably less than 1/3. In other words, the thickness of the crystalline phosphides containing layer, average thickness and less desirably equivalent insulation coating containing no crystalline phosphide, more preferably at most half the thickness of the insulating film.
[0080]
　The lower limit of the thickness of the crystalline phosphides containing layer is not particularly limited, in terms of reliably ensuring a film adhesion of the insulating film, on average, the thickness of the insulating film containing a crystalline phosphide-containing layer 1 / 10 or more. More preferably 1/7 or more. In other words, the thickness of the crystalline phosphides containing layer, on average, 1/9 or more of the thickness is preferably of an insulating film containing no crystalline phosphide, more preferably not less than 1/6 of the thickness of the insulating film .
[0081]
　Abundance of crystalline phosphide contained in the crystalline phosphides containing layer is the ratio of the cross-sectional area of ​​the total crystalline phosphide to the cross-sectional area of ​​the entire crystalline phosphide-containing layer including the crystalline phosphides area fraction (hereinafter sometimes referred to as "cross-sectional area ratio".) is displayed at.
[0082]
　Sectional area ratio of the crystalline phosphide is small (the amount present is small), so does not improve film adhesion of the insulating film, cross-sectional area ratio of the crystalline phosphides more than 5% on average is preferred. More preferably 10% or more.
[0083]
　On the other hand, the cross-sectional area ratio of the crystalline phosphide is large (the amount of presence is large), the proportion of amorphous decreases in the crystalline phosphide-containing layer, the crystalline phosphide-containing layer and the insulating film (in the insulating film since adhesion between the region) which does not contain the crystalline phosphide-containing layer is reduced, cross-sectional area ratio of the crystalline phosphides is preferably less than 50% on average. More preferably 35% or less.
[0084]
　If the particle size of the crystalline phosphide present in the crystalline phosphide-containing layer is small, the stress relaxation effect is not sufficiently obtained, a circle equivalent diameter of the crystalline phosphide present in the crystalline phosphides containing layer average in 5nm or more. More preferably 10nm or more.
[0085]
　On the other hand, if the particle size of the crystalline phosphide is large, the crystallinity phosphide may become starting points of fracture due to stress concentration, the circle equivalent diameter of crystalline phosphide present in the crystalline phosphides containing layer 300nm or less on average It is preferred. More preferably not more than 270nm. However, a circle equivalent diameter of the crystalline phosphides must be less than the thickness of the crystalline phosphide-containing layer.
[0086]
　Crystalline phosphide crystallinity phosphide-containing layer contains may be any phosphide crystalline stress relaxation effect is obtained, in particular, not limited to a particular crystalline phosphide.
[0087]
　For example, crystalline phosphides are compounds containing phosphorus, chemical components, Fe, Cr, P, and O is the total content of less and 100 atomic% 70 atomic% or more, Si is 10 atomic% or less it may be a restricted compounds. E.g., P content of the crystalline phosphides may be less than 0 atomic percent and 70 atomic%. Note that the remainder of the chemical composition of the compound may be an impurity. The term "impurities" refers to those mixed from raw materials or manufacturing environment and the like.
[0088]
　For example, crystalline phosphides, Fe 3 P, Fe 2 P, FeP, FeP 2 , Fe 2 P 2 O 7 , (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P , (Fe, Cr) P 2 , (Fe, Cr) 2 P 2 O 7 is preferably, one or more. Here, for example (Fe, Cr) P is meaning (other crystalline phosphide versa) that part of Fe of FeP is replaced with Cr. Substitution rate of Cr crystalline phosphides containing Cr is not particularly limited, preferably small than 70 atomic percent greater than 0 atomic%.
[0089]
　For example, in the case of oriented crystalline phosphides which part of Fe is not substituted with Cr as crystalline phosphide, FeP, Fe 2 P, Fe 3 P, FeP 2 or Fe, 2 P 2 O 7 , the at least one need be included.
[0090]
　Similarly, in the case of oriented crystalline phosphides partially substituted in the Cr of Fe as crystalline phosphide, (Fe, Cr) P, (Fe, Cr) 2 P, (Fe, Cr) 3 P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 , it suffices contain at least one.
[0091]
　As described above, features of the present invention electrical steel sheet, the lower region of the insulating film, in contact onto an intermediate layer of silicon oxide mainly crystalline phosphides containing layer containing crystalline phosphide is formed it is.
[0092]
　Composition of the base material steel plate (chemical composition), since not directly related to the presence of crystalline phosphide-containing layer, in the present invention electrical steel sheet, composition of the base steel sheet is not particularly limited. However, oriented electrical steel sheet, because it is produced through various processes, for composition of the preferred material billet (slab) and the base steel sheet in order to produce the present invention electrical steel will be described below. Hereinafter,% of the component composition of the material steel strip and the base steel sheet refers to mass%.
[0093]
　Composition of the base material steel plate
　base material steel plate of the present invention electrical steel sheet, for example, Si: contains 0.8 ~ 7.0%, C: 0.005 % or less, N: 0.005% or less, S and the total amount of Se: 0.005% or less, and acid-soluble Al: limited to 0.005% or less, the balance being Fe and impurities.
[0094]
　Si: 0.80% or more and 7.0% or less
　Si (silicon) reduces the iron loss by increasing the electrical resistance of the grain-oriented electrical steel sheet. A preferable lower limit of Si content is 0.8%, more preferably 2.0%. On the other hand, when the Si content exceeds 7.0%, the saturation magnetic flux density of the base material steel plate is lowered, size of the core is hard. The preferable upper limit of the Si content is 7.0%.
[0095]
　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. The preferable upper limit of the C content is 0.004%, more preferably 0.003%. Since C is as small as preferred, including 0% lower limit, the reduce C to less than 0.0001%, the manufacturing cost is greatly increased, manufacturing, 0.0001% is substantially the lower.
[0096]
　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%. Since N as less preferable, the lower limit need only be 0%.
[0097]
　The total amount of S and Se: 0.005% or less
　S (sulfur) and Se (selenium) forms a compound in the base steel sheet in order to degrade the iron loss, the less preferred. One of S or Se, or it is preferred to limit the sum of both the 0.005% or less. The total amount of S and Se is preferably 0.004% or less, more preferably 0.003% or less. Because the content of S or Se is the less preferred, the lower limit need only be 0%, respectively.
[0098]
　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. Acid-soluble Al is preferably 0.005% or less. Acid-soluble Al is preferably 0.004% or less, more preferably 0.003% or less. Since the acid-soluble Al is as small as possible preferably, the lower limit need only be 0%.
[0099]
　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.
[0100]
　Also, the base material steel plate of the present invention electrical steel sheet, 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 (molybdenum) it may contain at least one member selected from.
[0101]
　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%. These selection elements be contained as an impurity, the effect of the present invention electrical steel sheet 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.
[0102]
　Chemical composition of the material billet (slab)
　C (carbon) is an element effective in controlling the primary recrystallized texture. C is preferably 0.005% or more. Further, C is 0.02% or more, 0.04% or more, more 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.
[0103]
　When Si (silicon) 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 the Si is more than 4.00% the base steel sheet is hardened workability is deteriorated, since the cold rolling becomes difficult, it is necessary to make the equipment measures such as warm rolling. From the viewpoint of processability, Si is preferably not more than 4.00%. More preferably not more than 3.80%.
[0104]
　When Mn (manganese) 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 the Mn 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 from 0.13%.
[0105]
　When the acid-soluble Al (acid soluble Aluminum) 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 0. more than 010 percent is preferred. More preferably 0.015% or more. On the other hand, if the acid soluble Al is more than 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.
[0106]
　When N (nitrogen) 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 represents preferably 0.004% or more. More preferably 0.006% or more. On the other hand, when N exceeds 0.015%, nitride during hot rolling it is a large amount and unevenly deposited, since hinders the progress of recrystallization, N is preferably 0.015% or less. More preferably not more than 0.013%.
[0107]
　When one or both sum of S (sulfur) and Se (selenium) is less than 0.005%, insufficient precipitation amount of MnS and / or MnSe functioning as inhibitors, secondary recrystallization is sufficiently stable does not proceed Te, total of one or both of S and Se is preferably 0.005% or more. More preferably 0.007% or more. On the other hand, if the total amount of S and Se 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 0.050% or less It is preferred. More preferably not more than 0.045%.
[0108]
　Balance of chemical composition of the material steel strip 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.
[0109]
　Also, material steel strip of the present invention electrical steel sheet, in a range that does not disturb a property as a selective element in place of part of Fe is the balance, for example, P, Cu, Ni, Sn, and one Sb or it may contain two or more. The lower limit of the selection element is not particularly limited, the lower limit may be 0%.
[0110]
　P (phosphorus) is to increase the electrical 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 increases the hardness , preferably 0.50% or less. More preferably not more than 0.35%.
[0111]
　Cu (copper) is to form 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 the magnetic properties is saturated, heat rolling, it may cause surface defects, preferably 0.40% or less. More preferably not more than 0.35%.
[0112]
　Ni (nickel) is to increase 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%, since the secondary recrystallization becomes unstable, Ni is 1.00% or less. More preferably not more than 0.75%.
[0113]
　Sn (tin) and Sb (antimony) is segregated at the 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, de because coal is less likely to proceed, Sn and Sb are both preferably 0.30% or less. More preferably, each element also below 0.25%.
[0114]
　Also, material steel strip of the present invention electrical steel sheet further as a selection element in place of part of Fe is the balance, for example, as an element for forming the inhibitor, Cr, Mo, V, Bi, Nb, the Ti one or more may contain a supplementary. The lower limit of the selection element is not particularly limited, the lower limit may be 0%. The upper limit of these elements, respectively, Cr: 0.30%, Mo: 0.10%, V: 0.15%, Bi: 0.010%, Nb: 0.20%, Ti: 0.015 it may be a%.
[0115]
　Next, a method for manufacturing of the present invention electrical steel sheet.
[0116]
　Method for producing a grain-oriented electrical steel sheet according to the present embodiment (hereinafter sometimes referred to as "production method of the present invention".) Has
　a coating of inorganic mineral forsterite or the like produced in (a) finish annealing, pickling, annealing the base material steel plate was removed by means of grinding or the like, or,
　(b) finish annealing at annealing the base material steel plate that suppresses the generation of the film of the inorganic mineral,
　(c) the annealing (thermal oxidation annealing, by annealing) in an atmosphere having a controlled dew point, to form an intermediate layer mainly composed of silicon oxide on the surface of the base material steel plate,
　mainly (d) is on the intermediate layer, phosphate and colloidal silica, baked by applying a crystalline phosphide-containing layer forming solution containing a crystalline phosphide,
　(e) after the above baking, mainly of phosphate and colloidal silica, the insulating film formation solution containing no crystalline phosphides in addition baked and coated.
　The present invention production process, the lower region of the insulating film, it is possible to form the crystalline phosphide-containing layer in contact with the intermediate layer.
[0117]
　Folder pickling a coating of inorganic minerals stellite or the like, the base material steel plate was removed by means of grinding or the like, and, the base material steel plate that suppresses the generation of oxide layer of the inorganic mineral, for example, as follows to produce.
[0118]
　The silicon steel strips containing 0.80 to 4.00 wt% of Si, preferably a silicon steel strips containing 2.0-4.0 mass% of Si, and hot rolled, optionally after hot rolling annealed Te, then once or is subjected to two or more cold rolling sandwiching the intermediate annealing, finish the steel sheet of the final sheet thickness. Then, the steel sheet of the final sheet thickness, subjected to decarburization annealing, in addition to decarburization, with the progress of the primary recrystallization, to form an oxide layer on the surface of the steel sheet.
[0119]
　Next, the surface of the steel sheet having an oxide layer, magnesia dried by applying an annealing separator mainly comprised of, 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 forsterite film composed mainly of) The forsterite coating, pickling, is removed by means of grinding or the like. After removal, preferably smoothly finished surface of the steel sheet by chemical polishing or electrolytic polishing.
[0120]
　On the other hand, as the above-described annealing separator, it is possible to use an annealing separator consisting mainly of alumina instead of magnesia. The surface of the steel sheet having an oxide layer, the alumina is dried by applying an annealing separator mainly comprised of, after drying, wound in a coil shape, subjected to finish annealing (secondary recrystallization). When using an annealing separator consisting mainly of alumina, even when the finish annealing, it is prevented to generate the coating of inorganic mineral forsterite or the like on the surface of the steel sheet. After finish annealing, preferably, smoothly finished surface of the steel sheet by chemical polishing or electrolytic polishing.
[0121]
　The base steel sheet to remove a film of inorganic mineral such as forsterite, or the base material steel plate that suppresses the generation of the film of the inorganic minerals such as forsterite, and annealed in a conventional annealing conditions, of the base material steel plate forming an intermediate layer mainly composed of silicon oxide on the surface.
[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 ~ 0 ° C..
[0123]
　The thickness of the intermediate layer of silicon oxide entity, the annealing temperature, holding time, and controls one of the dew point of the annealing atmosphere or two or more appropriate adjustment to. The thickness of the intermediate layer, in terms of securing the film adhesion of the insulating film, 2 ~ 400 nm is preferred on average. More preferably from 5 ~ 300nm.
[0124]
　On the intermediate layer of silicon oxide mainly composed mainly of phosphate and colloidal silica, baked by applying a crystalline phosphide-containing layer forming solution containing a crystalline phosphide.
[0125]
　Crystalline phosphides as chemical components, Fe, Cr, P, and O is the total content of 70 at% or more and 100 atomic percent, it may be used compounds which Si is limited to 10 atomic% or less . Note that the remainder of the chemical composition of the compound may be an impurity.
[0126]
　For example, crystalline phosphides, Fe 3 P, Fe 2 P, FeP, FeP 2 , Fe 2 P 2 O 7 , (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P , (Fe, Cr) P 2 , (Fe, Cr) 2 P 2 O 7 is preferably, one or more.
[0127]
　The average diameter of the crystalline phosphides is preferably 10 ~ 300 nm. Also, crystalline phosphide crystalline phosphide-containing layer forming solution is preferably 3 to 35% weight ratio.
[0128]
　In the present invention production process, after the above-mentioned baking using a crystalline phosphide-containing layer forming solution, further baked by applying an insulating film-forming solution without crystalline phosphide mainly of phosphate and colloidal silica.
[0129]
　By two baking annealing described above, it is possible to form a crystalline phosphides containing layer in contact with the intermediate layer, and an insulating film containing no crystalline phosphides in contact over the crystalline phosphide-containing layer.
[0130]
　The above baking, oxidation degree P of the atmosphere H2 O / P H2 steam from 0.001 to 1.0 - nitrogen - in a hydrogen mixed atmosphere, carried out by heat treatment 5-300 seconds 350 ~ 1150 ° C.. In this heat treatment, it is possible to lower region, an insulating film having a crystalline phosphide-containing layer in contact with the intermediate layer. To exhibit good reproducibility adhesion of the insulating coating, oxidation degree P H2 O / P H2 of 0.01-0.15, the baking temperature 650 ~ 950 ° C., more be a retention time of 30 to 270 seconds preferable. After the heat treatment, as crystalline phosphide is not chemically changed (as crystalline phosphide during cooling is not deteriorated capture moisture), and it holds a low degree of oxidation of atmosphere, cooling the steel sheet. Cooling atmosphere, oxidation degree P H2 O / P H2 is preferably 0.01 or less in the atmosphere.
[0131]
　Each layer of the present invention electrical steel sheet is observed as follows, measured.
[0132]
　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).
[0133]
　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.
[0134]
　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.
[0135]
　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 material steel plate, the intermediate layer and the insulating film (including a crystalline phosphide-containing layer) it is determined that there.
[0136]
　With respect to those regions except the base steel sheet specified above, from the quantitative analysis results of observation and SEM-EDS in COMP image, except for measurement noise, Fe content is less than 80 atomic%, P content is 5 atomic% above, Si content is less than 20 atomic%, O content of 50 atomic% or more, an area where the Mg content is 10 atomic% or less, and the line segment (thickness of the scanning line of the line analysis for this region if is) is 300nm or more, it is determined that the region is an insulating film (including a crystalline phosphide-containing layer).
[0137]
　Incidentally, in determining a region which is above an insulating film (including a crystalline phosphide-containing layer), without a like precipitates and inclusions contained in the insulating film on the judgment of a subject, said as matrix phase the region that satisfies the quantitative analysis result of determining that the insulating film (including a crystalline phosphide-containing layer). 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, not put this space to a subject with an insulating film by quantitative analysis of the matrix phase 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.
[0138]
　A region excluding the identified base material steel plate and the insulating film (including a crystalline phosphide-containing layer) above, if and line segment (thickness) of the scan line of the corresponding line analysis in this area is the 300nm or more if it is determined this region to be a middle layer. The intermediate layer may preferably be identified using TEM as needed.
[0139]
　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 (including the crystalline phosphide-containing layer), the maximum and minimum values ​​from the values ​​excluding the by the average value of the average value intermediate layer average thickness, and the average thickness of the insulating film (including a crystalline phosphide-containing layer).
[0140]
　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.
[0141]
　Test pieces comprising a layer to be observed in detail by using TEM, the by FIB (Focused Ion Beam) processing, cut into cutting direction is parallel to the thickness direction (specifically, the cut surface and the thickness direction parallel and was cut out so that the rolling direction and the vertical), the cross-sectional structure of the cut surface is observed by STEM (Scanning-TEM) at a magnification of layers corresponding in the observation field of view enters (bright field image) . If during the observation field of view from entering each layer, observing a cross section structure in successive multiple field-of-view.
[0142]
　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.
[0143]
　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.
[0144]
　Regions Fe content is 80 atomic% or more except for measurement noise is determined that the base steel sheet, a region excluding the base material steel plate, the intermediate layer and the insulating film (including a crystalline phosphide-containing layer) it is determined that it is.
[0145]
　With respect to those regions except the specified base material steel plate by the above, the quantitative analysis results of observation and TEM-EDS in a bright-field image, with the exception of the measurement noise, Fe content is less than 80 atomic%, P content is 5 atomic % or more, Si content of less than 20 atomic%, O content of 50 atomic% or more, it is determined that the region where the Mg content is 10 atomic% or less, which is an insulating film (including a crystalline phosphide-containing layer) . Incidentally, in determining a region which is above an insulating film (including a crystalline phosphide-containing layer), without a like precipitates and inclusions contained in the insulating film on the judgment of a subject, said as matrix phase the region that satisfies the quantitative analysis result of determining that the insulating film (including a crystalline phosphide-containing layer).
[0146]
　It is determined that the intermediate layer regions except the specified base material steel plate and the insulating film (including a crystalline phosphide-containing layer) above. The intermediate layer is, as an average of the entire intermediate layer is less than 80 atomic% Fe content on average, less than 5 atomic% P content is average, Si content average 20 atomic% or more, O content is average in 50 atom% or more, Mg content may be satisfied 10 atomic% or less on average. Incidentally, the quantitative analysis of the intermediate layer described above does not include an analysis of such precipitates or inclusions contained in the intermediate layer, a quantitative analysis of the matrix phase.
[0147]
　The intermediate layer and the insulating film specified above (including the crystalline phosphide-containing layer), 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 point analysis, for example, 2nm intervals along the thickness direction, to measure the respective layers of the segments (thickness), the line segment as the thickness of each layer it may be adopted. For example, with the use of the TEM with a spherical aberration correcting function, it is possible to EDS analysis in the spatial resolution of about 0.2 nm.
[0148]
　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.
[0149]
　In the present invention electrical steel sheet, in contact with the base steel sheet is present intermediate layer, the insulating film in contact with the intermediate layer (including the crystalline phosphide-containing layer) is present, each layer in the above criteria If identified, the base material steel plate, an intermediate layer, and a layer other than the insulating film (including a crystalline phosphide-containing layer) is not present.
[0150]
　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 its thickness to identify the insulating film it is a criterion for determining.
[0151]
　Next, the crystalline phosphide-containing layer is to confirm whether or not present in the insulating film in specified above.
[0152]
　Based on the identification result of the above-mentioned insulating film (including a crystalline phosphide-containing layer), a test piece including an insulating film, by FIB processing, cut into cutting direction is parallel to the thickness direction (specifically, cut surface was cut out such that the thickness direction and parallel to and rolling direction and vertical), the cross-sectional structure of the cut surface is observed with TEM at a magnification of insulating film enters into the observation field.
[0153]
　The insulating film in the observation field, performs a wide-area electron diffraction of the electron beam diameter as the smaller of 1/10 or 200nm insulating film, some or crystalline phase is present in the electron beam irradiation region the whether to confirm the electron diffraction pattern.
[0154]
　If it is confirmed with the electron beam diffraction pattern in the crystalline phase is present, check the object of the crystalline phase in the bright field image, an analysis point by TEM-EDS for this crystalline phase. The TEM-EDS results of the analysis points by the chemical components of the crystalline phase of interest is, Fe, Cr, P, and O is the total content of less and 100 atomic% 70 atomic% or more, Si is 10 atom if less%, it can be determined that the crystalline and is and phosphorus containing phase, to determine the crystalline phase and the crystalline phosphide.
[0155]
　If necessary, relative to the crystalline phase dealt with the above, performs electron diffraction squeezed electron beam so that the information from only the crystalline phase of the target is obtained, the target from the electron beam diffraction pattern to identify the crystal structure of the crystalline phase to be. This identification may be performed by using the ICDD (International Centre for Diffraction Data) of the PDF (Powder Diffraction File).
[0156]
　From the above-mentioned TEM-EDS point analysis and electron diffraction results, the crystalline phase, Fe 3 P, Fe 2 P, FeP, FeP 2 , Fe 2 P 2 O 7 , (Fe, Cr) 3 P, (Fe , Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , (Fe, Cr) 2 P 2 O 7 can determine whether it is.
[0157]
　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 2 identification of whether it is is, PDF: No. It may be carried out based on 01-089-2261. Crystalline phase is Fe 2 P 2 O 7 identified if it is a can, PDF: No. It may be carried out based on 01-076-1762. Crystalline phase (Fe, Cr) 3 P in which one of the identification, Fe 3 P of PDF: No. 01-089-2712 or Cr 3 P of PDF: No. It may be carried out based on 03-065-1607. Crystalline phase (Fe, Cr) 2 if it were P identified, Fe 2 of P PDF: No. 01-078-6749 or Cr 2P of PDF: No. It may be carried out based on 00-045-1238. Crystalline phase (Fe, Cr) of identifying a P is the FeP PDF: No. 03-065-2595 or CrP of PDF: No. It may be carried out based on 03-065-1477. Crystalline phase (Fe, Cr) P 2 or identification is the, FeP 2 of PDF: No. 01-089-2261 or CrP 2 of the PDF: No. It may be carried out based on 01-071-0509. Crystalline phase (Fe, Cr) 2 P 2 O 7 if they were identified, Fe 2 P 2 O 7 the PDF: No. 01-076-1762 or Cr 2 P 2 O 7 of the PDF: No. It may be carried out based on 00-048-0598. In the case of identification based crystalline phase above the PDF, it is sufficient to identify the tolerance ± 3 ° tolerance ± 5% and inter-plane angle of the surface interval.
[0158]
　Checking whether any crystalline phase in the electron beam irradiation region described above is present (the wide-area electron beam irradiation), along the thickness direction, an insulating film (including a crystalline phosphide-containing layer) and the intermediate layer toward the interface from the outermost surface of the performed sequentially so that no gaps, repeated confirmation of the electron beam diffraction pattern to be the electron beam irradiation region is not present crystalline phase is confirmed.
[0159]
　By repeating the electron beam irradiation along the thickness direction as described above, we can identify areas whether crystalline phosphide in an insulating film is present, and crystalline phosphide in an insulating film exists. A region where there are crystalline phosphide in the insulating film, it is determined that the crystalline phosphide-containing layer.
[0160]
　The crystalline phosphides containing layer as specified above, a line segment (thickness) of the crystalline phosphide-containing layer with a scanning line of said electron beam irradiation, i.e., the region where there is crystalline phosphide in an insulating film measuring the thickness direction of the line segment (thickness).
[0161]
　The confirmation of whether crystalline phosphide-containing layer is present in the insulating film as described above, by changing the observation field is carried out in five locations or more. The thickness of the crystalline phosphide-containing layer obtained in a total of five points or more, with an average value from the values ​​excluding the maximum value and the minimum value, adopts the average value as the average thickness of the crystalline phosphide-containing layer to.
[0162]
　Further, the specified crystalline phosphide-containing layer in the above, and based on the crystalline phosphides identified above, determine the area fraction of crystalline phosphide by image analysis. Specifically, the total cross-sectional area of ​​the crystalline phosphides containing layer present electron beam irradiation (wide area electron beam irradiation) and carried within the area five or more locations of the observation field, the crystalline phosphides containing layer determining the area fraction of the crystalline phosphide and a total cross-sectional area of ​​the crystalline phosphide present within. For example, the total cross-sectional area of ​​the crystalline phosphide, a value obtained by dividing by the total cross-sectional area of ​​the crystalline phosphide-containing layer is employed as the average area fraction of crystalline phosphide. Incidentally, the binarized image for image analysis is based on the identification results of the crystalline phosphide, perform coloring crystalline phosphide-containing layer and the crystalline phosphide manually to tissue Photos image may be binarized Te.
[0163]
　Further, based on the crystalline phosphides specified above, finding the circle equivalent diameter of crystalline phosphide by image analysis. Calculated equivalent circle diameter of at least 5 or more crystalline phosphide in each five or more locations of the observation field, and an average value by excluding the maximum and minimum values ​​from the equivalent circle diameter determined, the average value employing as the average equivalent circular diameter of the crystalline phosphide. Incidentally, the binarized image for image analysis is based on the identification results of the crystalline phosphide, by binarizing the image by performing the coloring crystalline phosphide manually to tissue Photos it may be.
[0164]
　In addition, by SEM-EDS quantitative analysis or TEM-EDS quantitative analysis, the Cr content may be determined in units atomic% contained in the region of the insulating film except the crystalline phosphide-containing layer.
[0165]
　Also, Ra (arithmetic average roughness) of the base material steel plate surface may be measured by using a stylus type surface roughness measuring instrument.
[0166]
　Film adhesion of the insulating film is evaluated by the bending adhesion test. A flat test piece 80 mm × 80 mm, after winding a round bar having a diameter of 20 mm, flat stretched, the area of ​​this area of ​​the insulating film is not peeled off from the electromagnetic steel sheet were measured, the area is not peeled off the steel plate define a value obtained by dividing the film remaining area rate (%), to evaluate the film adhesion of the insulating film. For example, a transparent film with a 1mm grid tick marks placed on the specimen may be calculated by measuring the area of ​​the release and non insulation coating.
[0167]
　Core loss oriented electrical steel sheet (W 17/50 ), the AC frequency is 50 Hz, the induced magnetic flux density is measured at 1.7 Tesla.
Example
[0168]
　Will be further specifically described in detail the effects of an embodiment of the present invention through examples, the conditions in the examples, in one example of conditions adopted for confirming the workability and effects of the present invention There, the present invention is not limited to this single example of conditions. 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.
[0169]
　(Example 1)
　Table subjected 1 to the steel material pieces compositions shown after heated 60 minutes soaking at 1150 ° C. 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., and immediately cooled, and held for 120 seconds at 900 ° C., was subjected to hot rolled sheet annealing to subsequent quenching. After pickling the hot-rolled annealed sheets were subjected to cold rolling to obtain a cold rolled steel sheet of a final thickness 0.23 mm.
[0170]
[Table 1]

[0171]
　This cold-rolled steel sheet (hereinafter "steel"), hydrogen: nitrogen 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.
[0172]
　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 finish-annealed by heating to 1200 ° C. at a heating rate of 15 ° C. / time, then, in a hydrogen atmosphere, subjected to purification annealing holding at 1200 ° C. 20 h, allowed to cool, to produce a base material steel plate having a smooth surface.
[0173]
　The prepared base material steel plate, 25% N 2 + 75% H 2 , dew point: -2 ° C. atmosphere, 950 ° C., annealing under conditions of 240 seconds, the surface of the base steel sheet, the average thickness of 9nm silicon oxide to form an intermediate layer of principal.
[0174]
　An intermediate layer of silicon oxide mainly baked by applying a crystalline phosphide-containing layer forming solution having crystallinity phosphide to form a crystalline phosphide-containing layer. In the lower region of the insulating film, thereby reliably forming the crystalline phosphide-containing layer in contact with the intermediate layer of silicon oxide mainly for reliably securing the insulating property of the insulating film, and further applying an insulating film-forming solution baking , forming an insulating film containing no crystalline phosphide. In this way, the application was conducted and baking processing of a total of two times.
[0175]
　First time, magnesium phosphate, colloidal silica, 100 parts by weight of a solution composed mainly of an aqueous solution of chromic anhydride, FeP, (Fe, Cr) P, Fe 2 P, (Fe, Cr) 2 P, Fe 3 P, FeP 2 , Fe 2 P 2 O 7 , (Fe, Cr) 2 P 2 O 7 1 or more kinds of powder 0-40 parts by mass crystalline a solution prepared by mixing and stirring the crystalline phosphide as phosphide-containing layer forming solution, usual coating amount of X (= 1/10 ~ 1 /2) by multiplying the coating and baked under the conditions of baking annealing shown in Table 2.
[0176]
　The particle size of the crystalline phosphides mixed crystalline phosphide-containing layer forming solution, except for the specimen A5, was 10 ~ 300 nm in average diameter. The particle size of the crystalline phosphides of mixed crystalline phosphide-containing layer forming solution used in the production of the test specimen A5 had a 300nm than the average diameter.
[0177]
　Cooling after baking takes in crystalline phosphide-containing layer water cooled (thermal contraction) developing, as crystalline phosphide is not altered, with the exception of the test piece A9, oxidation degree P of the atmosphere upon cooling H2O / P H2 was performed is set as follows.
　　Temperature range of baking temperature 700 ° C. ~: P H2 O / P H2 ≦
　　0.01 700 ° C. ~ 300 ° C. temperature range: P H2 O / P H2 ≦ 0.008
[0178]
　This coating and baking and cooling, the crystalline phosphide, distributed in the lower region of the insulating film, it is possible to form the crystalline phosphide-containing layer in contact with the intermediate layer.
[0179]
　The second time, the insulating film formation solution without the same crystalline phosphide and above the usual amount of coating (1-X) times by applying (Table 3, see), respectively, the same baking the first It was baked under the conditions of annealing. This coating and baking, on the crystalline phosphide-containing layer, it is possible to form an insulating film containing no crystalline phosphide having an excellent insulating property.
[0180]
　Table 2 shows the first coating and baking and cooling conditions.
[0181]
[Table 2]

[0182]
　According to the method of observation and measurement described above, cut out test pieces from the formed oriented electrical steel sheet insulating coating, the coating structure of the test piece was observed with a scanning electron microscope (SEM) or transmission electron microscope (TEM), the thickness of the insulating film, and, to measure the thickness of the crystalline phosphide-containing layer.
[0183]
　In TEM image of crystalline phosphide-containing layer, the chemical composition of the crystalline phosphide were analyzed by TEM-EDS, was identified structure of crystalline phosphide by electron diffraction.
[0184]
　In TEM image of crystalline phosphide-containing layer, a matrix and (insulating coating part) a crystalline phosphide distinguished by binarizing by an image analysis, the total cross-sectional area of ​​the crystalline phosphide crystalline phosphides area fraction of (%) was calculated.
[0185]
　In TEM image of crystalline phosphide-containing layer, a matrix and (insulating coating part) a crystalline phosphide distinguished by binarizing by an image analysis to determine the circle equivalent diameter of crystalline phosphide. The results are shown in Table 3.
[0186]
　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 stretch, the area of ​​the insulating film is not peeled off from the electromagnetic steel plate measured and was calculated film remaining area ratio. The results are shown in Table 3.
[0187]
[table 3]

[0188]
　Although not shown in the table, the chemical composition of the crystalline phosphide contained in the crystalline phosphides containing layer, Fe, Cr, P, and O total content 70 atomic% or more and 100 atomic% or less in it, Si was equal to or less than 10 atomic%.
[0189]
　In the invention example having crystallinity phosphide-containing layer, as compared with Comparative Example A1 and A11 having no crystalline phosphide-containing layer high film residual area ratio, film adhesion of the insulating film is remarkably excellent it can be seen. By amorphous and crystalline crystalline phosphide-containing layer is mixed well-balanced, are relaxed stress accumulated therein, it is considered that plaques are eliminated film adhesion.
[0190]
　In particular, in the test piece A2, A3, A7, A8, abundance of crystalline phosphide, size, the thickness of the crystalline phosphide-containing layer is preferred, not only film adhesion alone, iron loss It is also very good.
[0191]
　On the other hand, the total cross-sectional area ratio of the crystalline phosphide crystalline phosphide-containing layer of the test piece A4 in order to be 55% and increased the proportion of amorphous small, conversely, the crystallinity of the test specimen A6 total cross-sectional area ratio of the crystalline phosphide phosphide-containing layer in order to be 3% and lower, the proportion of crystalline small, it is considered that improvement of the coating adhesion remained slightly.
[0192]
　The average particle size of the crystalline phosphide specimens A5 is 445 nm, the average particle size of the crystalline phosphide specimens A9 to as large as 336 nm, crystalline phosphide become starting points of fracture due to stress concentration, film improvement in adhesion can be considered that remained slightly. Crystalline phosphide-containing layer of the test piece A9 is applicable to the structure of the present invention, oxidation degree P of the atmosphere during the post-baking cooling H2 O / P H2 in higher than 0.01, the crystalline phosphides incorporating a small moisture-containing layer in the cooling developing, crystalline phosphide altered, there is a possibility that coating adhesion is degraded by some mechanism.
[0193]
　Although film adhesion of the test piece A10 is good, since the insulating film containing no crystalline phosphides containing layer is thin, can not be exerted to maximize the tension of the steel sheet, the improvement of iron loss characteristics remained slightly It was believed to be.
[0194]
　Incidentally, the test piece A4 (Fe, Cr) 2 P, (Fe, Cr) in the test piece A7 P, (Fe, Cr) in the test piece A8 ~ A10 2 P 2 O 7　were detected, these, and Cr of chromic anhydride caused contained in the insulating film formation solution and the crystalline phosphide are those produced by the reaction. Substitution ratio of Cr to Fe ranged from 5 to 65% elemental ratio.
[0195]
　Although the same manufacturing conditions as the test piece A2 described above were also tested for changing only crystalline phosphide to be mixed with the crystalline phosphides containing phase forming solution.
　To a solution in the test piece A12 (Fe, Cr) 3 were mixed P prepared in crystalline phosphide-containing layer (Fe, Cr) 3 was confirmed that P exists.
　To a solution in the test piece A13 (Fe, Cr) P 2 were prepared by mixing, in crystalline phosphide-containing layer (Fe, Cr) P 2 it was confirmed that there.
　Evaluation results of these test pieces A12 and A13 was confirmed to be equivalent to the evaluation result of the test piece A2.
Industrial Applicability
[0196]
　According to this aspect of the present invention, grain-oriented electrical steel sheet having an insulation coating unevenness is not in film adhesion, i.e., even without forsterite coating provides excellent oriented electrical steel sheet film adhesion of the insulating film be able to. Thus, there is a high availability of the industry.
DESCRIPTION OF SYMBOLS
[0197]
　1 the base steel sheet
　2 forsterite film
　3 insulating film
　4 intermediate layer
　5 crystalline phosphide
　6 crystalline phosphides containing layer

WE claims

[Requested item 1]
　A base steel sheet, and an intermediate layer disposed in contact on the base steel sheet, in the oriented electrical steel sheet having an insulating film serving as the intermediate layer in contact with arranged that in the uppermost surface,
　the cutting direction thickness when viewed in cutting plane is parallel to the direction, the insulating film is, in a region in contact with on the intermediate layer, a crystalline phosphide-containing layer containing a crystalline phosphide
oriented electrical steel sheet, characterized in that .
[Requested item 2]
　When viewed in the cutting surface, the average thickness of the crystalline phosphide-containing layer, wherein at least one-tenth and one-half or less of the average thickness of the insulating film
according to claim 1, characterized in that of grain-oriented electrical steel sheet.
[Requested item 3]
　Wherein when viewed in cutting plane, the area fraction of the crystalline phosphide to said crystalline phosphide-containing layer is 5 to 50% on average
oriented electrical of claim 1 or 2, characterized in that steel sheet.
[Requested item 4]
　Wherein when viewed in cutting plane, the circle equivalent diameter of the crystalline phosphide is 5 ~ 300 nm in average
grain-oriented electrical steel sheet according to any one of claims 1 to 3, wherein the.
[Requested item 5]
　The crystalline phosphide, as chemical components, Fe, Cr, and contains P, and O a total of 70 atomic% or more and 100 atomic% or less, Si is limited to 10 atomic% or less
claims, characterized in that oriented electrical steel sheet according to any one of claim 1-4.
[Requested item 6]
　As the crystalline phosphide, FeP, Fe 2 P, Fe 3 P, FeP 2 , or Fe 2 P 2 O 7 contains at least one
oriented electrical steel sheet according to claim 5, characterized in that .
[Requested item 7]
　As the crystalline phosphide, (Fe, Cr) P, (Fe, Cr) 2 P, (Fe, Cr) 3 P, (Fe, Cr) P 2 or Cr), (Fe, 2 P 2 O 7 , at least one is contained in the oriented electrical steel sheet according to claim 5 or 6, characterized in that.