A pre-coating agent composition for a grain-oriented electrical steel sheet, a grain-oriented electrical steel sheet including the same, and a manufacturing method thereof are provided. Particularly, a pre-coating agent composition for a grain-oriented electrical steel sheet including an acid containing boron (B); and a solvent, a grain-oriented electrical steel sheet including the same, and a manufacturing method thereof are provided.

A chemical treatment steel sheet contains: a steel sheet; a plated layer containing Ni and formed on at least one surface of the steel sheet; a chemical treatment layer containing a Zr compound in which an amount of Zr contained therein is 1.0 to 150 mg/m.sup.2, a phosphate compound in which an amount of P contained therein is 1.0 to 100 mg/m.sup.2, and an Al compound in which an amount of Al contained therein is 0.10 to 30.0 mg/m.sup.2. The plated layer is a Ni-plated layer containing Ni in which an amount of Ni contained therein is 5.0 to 3000 mg/m.sup.2 or a composite plated layer containing Ni in which an amount of Ni contained therein is 2.0 to 200 mg/m.sup.2 and Sn in which an amount of Sn contained therein is 0.10 to 10.0 g/m.sup.2 and having an island-shaped Sn-plated layer formed on a FeNiSn alloy layer.

A chemical treatment steel sheet includes a steel sheet, an FeSn alloy layer which is formed on at least one surface of the steel sheet, a Sn layer which is formed on the FeSn alloy layer and contains Sn in which a total amount of Sn contained in the FeSn alloy layer and the Sn layer is 0.10 to 30.0 g/m.sup.2, and a chemical treatment layer which is formed on the Sn layer and contains a Zr compound in which an amount of Zr contained therein is 1.0 to 150 mg/m.sup.2, a phosphate compound in an amount of P contained therein is 1.0 to 100 mg/m.sup.2 and an Al compound in an amount of Al contained therein is 0.10 to 30.0 mg/m.sup.2.

An adhesion promoter composition foregoes the use of toxic heavy metals and also features a relatively large add-on window for an adhesion functioning in the assembly. The adhesion promoter composition is an aqueous solution comprising (a) -3 parts by weight of a polymer selected from the maleic acid/polyacrylic acid copolymer, modified polyacrylic acid, or polyacrylic acid groups; (b) 1 part by weight of a phosphate component; and optionally (c) 1/10 to 5/10 parts by weight of a metal-containing component selected from the Zn, Ca, Mg and/or Al group.

The present invention relates to an aqueous composition based on phosphates, aluminum ions and other metal ions, in particular manganese ions and zinc ions, as well as silicates, siloxanes or silanes, for providing anticorrosive coatings on metal surfaces, in particular for the electrical insulation of grain-oriented electrical steel strip. For the desired functionality, the compositions according to the invention contain the constituents mentioned in a prescribed ratio to one another. The invention also relates to a method for coating the surface of a metallic workpiece by using the aqueous compositions, wherein the method produces outstanding results, in particular on grain-oriented electrical steel strip, with regard to corrosion protection and adherence.

The present invention relates to an aqueous composition based on phosphates, aluminum ions and other metal ions, in particular manganese ions and zinc ions, as well as silicates, siloxanes or silanes, for providing anticorrosive coatings on metal surfaces, in particular for the electrical insulation of grain-oriented electrical steel strip. For the desired functionality, the compositions according to the invention contain the constituents mentioned in a prescribed ratio to one another. The invention also relates to a method for coating the surface of a metallic workpiece by using the aqueous compositions, wherein the method produces outstanding results, in particular on grain-oriented electrical steel strip, with regard to corrosion protection and adherence.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2), the insulating film (3) containing a polyvalent metal phosphate and Fe. A maximum value of a parameter Q expressed by Q=C.sub.FeO/C.sub.P is equal to or less than 1.3 times and equal to or more than 1.09 times an average value of the parameter Q in a region from a first depth from a surface of the insulating film to a second depth, C.sub.FeO denoting a proportion (atom %) of Fe bonded to O relative to all elements, and C.sub.P denoting a proportion (atom %) of P relative to all elements. The first depth is 20 nm from the surface, and the second depth is a depth where the proportion of P is equal to a proportion of metal Fe.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2), the insulating film (3) containing a polyvalent metal phosphate and Fe. A maximum value of a parameter Q expressed by Q=C.sub.FeO/C.sub.P is equal to or less than 1.3 times and equal to or more than 1.09 times an average value of the parameter Q in a region from a first depth from a surface of the insulating film to a second depth, C.sub.FeO denoting a proportion (atom %) of Fe bonded to O relative to all elements, and C.sub.P denoting a proportion (atom %) of P relative to all elements. The first depth is 20 nm from the surface, and the second depth is a depth where the proportion of P is equal to a proportion of metal Fe.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2). The insulating film (3) contains a phosphates of one or more selected from the group consisting of Al, Zn, Mg and Ca. The phosphate exhibits a specific peak having a top within a range of 26 ppm to 16 ppm in a solid .sup.31P-NMR spectrum, and a proportion of an integrated intensity of the specific peak relative to an integrated intensity of all peaks in the solid .sup.31P-NMR spectrum is 30% or more.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2). The insulating film (3) contains a phosphates of one or more selected from the group consisting of Al, Zn, Mg and Ca. The phosphate exhibits a specific peak having a top within a range of 26 ppm to 16 ppm in a solid .sup.31P-NMR spectrum, and a proportion of an integrated intensity of the specific peak relative to an integrated intensity of all peaks in the solid .sup.31P-NMR spectrum is 30% or more.