A coating composition and a method for coating metallic substrates, such as aircraft components exposed to elevated temperatures and/or oxidative conditions. The coating composition includes an aqueous mixture having about 2 vol % to about 50 vol % organosilane, about 0.3 to about 25 vol % metal alkoxide, and about 0.1 to about 30 vol % organic complexing agent. The coating composition may be deposited on a metallic substrate and cured to form a sol-gel coating on the surface of the substrate that is adherent to the substrate, and oxidation and discoloration resistant.

A coating composition and a method for coating metallic substrates, such as aircraft components exposed to elevated temperatures and/or oxidative conditions. The coating composition includes an aqueous mixture having about 2 vol % to about 50 vol % organosilane, about 0.3 to about 25 vol % metal alkoxide, and about 0.1 to about 30 vol % organic complexing agent. The coating composition may be deposited on a metallic substrate and cured to form a sol-gel coating on the surface of the substrate that is adherent to the substrate, and oxidation and discoloration resistant.

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). Three conditions (1.8≦3[Fe]/[P]+Σn.sub.M[M]/[P]≦3.6, 0.6≦Σn.sub.M[M]/[P]≦2.4, and 0.6≦3[Fe]/[P]≦2.4) are satisfied in a region of 50 area % or more of a cross section parallel to a thickness direction of the insulating film. [Fe] denotes a proportion (atom %) of Fe, [P] denotes a proportion (atom %) of P, [M] denotes a proportion (atom %) of each of Al, Zn, Mg and Ca, and n.sub.M denotes a valence of each of Al, Zn, Mg and Ca.

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). Three conditions (1.8≦3[Fe]/[P]+Σn.sub.M[M]/[P]≦3.6, 0.6≦Σn.sub.M[M]/[P]≦2.4, and 0.6≦3[Fe]/[P]≦2.4) are satisfied in a region of 50 area % or more of a cross section parallel to a thickness direction of the insulating film. [Fe] denotes a proportion (atom %) of Fe, [P] denotes a proportion (atom %) of P, [M] denotes a proportion (atom %) of each of Al, Zn, Mg and Ca, and n.sub.M denotes a valence of each of Al, Zn, Mg and Ca.

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.Fe—O/C.sub.P” is equal to or less than 1.3 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.Fe—O 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 phosphate of one or more selected from the group consisting of Al, Zn, Mg and Ca. A proportion of an amount by mole (mol) of Fe atoms relative to an amount by mole (mol) of P atoms in the insulating film (3) is more than 0.1 nor more than 0.65.

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 phosphate of one or more selected from the group consisting of Al, Zn, Mg and Ca. A proportion of an amount by mole (mol) of Fe atoms relative to an amount by mole (mol) of P atoms in the insulating film (3) is more than 0.1 nor more than 0.65.

This grain-oriented electrical steel sheet is a grain-oriented electrical steel sheet including a base steel sheet and a tension coating, in which, when an average coating thickness of a flat surface coating portion is referred to as t1 (μm), a minimum coating thickness of a groove forming surface coating portion is referred to as t2.sub.Min (μm), and a maximum coating thickness of the groove forming surface coating portion is referred to as t2.sub.Max (μm), Expressions (1) and (2) are satisfied, and when a value of 0.95 times a distance D of the tension coating along a sheet thickness direction from a bottom surface position of the groove forming surface coating portion to a bottom surface position of the flat surface coating portion is referred to as an effective depth d (μm), Expression (3) is satisfied.

t2.sub.Min/t1≥0.4  (1)

t2.sub.Max/t1≤3.0  (2)

t2.sub.Max≤d/2  (3)

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.

The present invention relates to a composition for forming an insulation coating film of an oriented electrical steel sheet, including a first component (A) including a composite metal phosphate, a derivative thereof, or a mixture thereof, and a second component (B) including at least two colloidal silicas having different average particle diameters, a method for forming an insulation coating film using the same, and an oriented electrical steel sheet having an insulation coating film formed thereon.