The object of the invention is to provide a surface-treated steel sheet having a coating having fine adhesiveness to an adhesive on the surface and having excellent corrosion resistance, and a production method thereof. Provided is a surface-treated steel sheet including: a steel sheet; a plated layer containing zinc on the steel sheet; and a coating on the plated layer, wherein the coating contains an acrylic resin, zirconium, vanadium, phosphorus and cobalt, and the acrylic resin has an area ratio of 80 to 100 area % in an area from a surface to a thickness of one-fifth of a film thickness of the coating, and an area ratio of 5 to 50 area % in an area including areas from the film thickness center of the coating to a thickness of one-tenth of the film thickness toward the surface side and toward the plated layer side.

The objectives of the present invention are: to provide a novel tetrazole silane compound, a method for synthesizing the same, and a silane coupling agent containing the tetrazole silane compound as a component; and to provide a surface treatment solution using the tetrazole silane compound, a method for surface treatment, and a method for adhering two different materials. The tetrazole silane compound according to the present invention is a compound represented by chemical formula (I). (In formula (I), X, R, and n are respectively the same as defined in the specification.)

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The objectives of the present invention are: to provide a novel tetrazole silane compound, a method for synthesizing the same, and a silane coupling agent containing the tetrazole silane compound as a component; and to provide a surface treatment solution using the tetrazole silane compound, a method for surface treatment, and a method for adhering two different materials. The tetrazole silane compound according to the present invention is a compound represented by chemical formula (I). (In formula (I), X, R, and n are respectively the same as defined in the specification.) ##STR00001##

The objectives of the present invention are: to provide a novel tetrazole silane compound, a method for synthesizing the same, and a silane coupling agent containing the tetrazole silane compound as a component; and to provide a surface treatment solution using the tetrazole silane compound, a method for surface treatment, and a method for adhering two different materials. The tetrazole silane compound according to the present invention is a compound represented by chemical formula (I). (In formula (I), X, R, and n are respectively the same as defined in the specification.) ##STR00001##

Adhesion of a metal surfaces (e.g. titanium and titanium alloys) to an epoxy resin is improved by creating a sol-gel layer at the metal/epoxy resin surface, with the sol-gel comprising a mixture of organometallic compounds to react with or bond to both the metal surfaces and an interfacing epoxy resin.

Adhesion of a metal surfaces (e.g. titanium and titanium alloys) to an epoxy resin is improved by creating a sol-gel layer at the metal/epoxy resin surface, with the sol-gel comprising a mixture of organometallic compounds to react with or bond to both the metal surfaces and an interfacing epoxy resin.

A near neutral pH pickling composition for the removal of oxides from metallic surfaces, including heat treated steel. The pickling composition comprises a) a water-soluble organic or inorganic nitro compound, wherein a central N atom has an oxidation state of 3+; b) a polarizing agent for the nitro compound, wherein the polarizing agent comprises at least one of a phosphonate and a carboxylate; c) a pH buffer, and d) at least one metal complexing agent. The composition is preferably maintained at a pH between about 4.5 and about 7.5. The near neutral pH pickle composition can be used on various metallic surfaces as well as composite surfaces comprising metallic and non-metallic portions.

An aqueous anti-rust surface treatment composition used for forming a film on a surface of a metal member of the present invention contains a silane coupling agent; a water-soluble transition metal compound containing a water-soluble titanium compound or a water-soluble zirconium compound; a condensed phosphate; and a solvent containing water, in which the condensed phosphate contains a highly condensed phosphate which is a salt of high condensate of equal to or more than four phosphoric acids.

An aqueous anti-rust surface treatment composition used for forming a film on a surface of a metal member of the present invention contains a silane coupling agent; a water-soluble transition metal compound containing a water-soluble titanium compound or a water-soluble zirconium compound; a condensed phosphate; and a solvent containing water, in which the condensed phosphate contains a highly condensed phosphate which is a salt of high condensate of equal to or more than four phosphoric acids.

A grain-oriented electrical steel sheet according to an aspect of the present invention includes: a steel sheet 1; an intermediate layer 4 containing Si and O, arranged on the steel sheet; and an insulation coating 3 arranged on the intermediate layer 4, in which the intermediate layer 4 contains a metal phosphide 5, a thickness of the intermediate layer 4 is 4 nm or more, and an abundance of the metal phosphide 5 present is 1% to 30% by cross-sectional area fraction in a cross section of the intermediate layer 4.