A method is provided for passivating an aluminum surface. According to the method, the aluminum surface is provided with a flux. A passivation solution is subsequently applied to the aluminum surface, such that a passivation layer is created by reaction of the passivation solution with the aluminum surface, which is provided with the flux.

A method is provided for passivating an aluminum surface. According to the method, the aluminum surface is provided with a flux. A passivation solution is subsequently applied to the aluminum surface, such that a passivation layer is created by reaction of the passivation solution with the aluminum surface, which is provided with the flux.

The grain-oriented electrical steel sheet is a grain-oriented electrical steel sheet which does not have an inorganic coating containing forsterite as a main component, including a base steel sheet having a predetermined chemical component, a silicon-containing oxide layer provided on the base steel sheet, an iron-based oxide layer provided on the silicon-containing oxide layer, and a tension-insulation coating provided on the iron-based oxide layer, having a thickness of 1 to 3 μm, and containing phosphate and colloidal silica as main components. When elemental analysis is performed from a surface of the tension-insulation coating in a sheet thickness direction by glow discharge optical emission spectrometry, predetermined requirements are satisfied.

An aluminum-based metal-resin composite structure (106) includes an aluminum-based metal member (103) in which a dendritic layer (103-2) is formed on at least a part of a surface, and a resin member (105) bonded to the aluminum-based metal member (103) via the dendritic layer (103-2) and formed of a thermoplastic resin composition, in which, when analysis is conducted with a Fourier transform infrared spectrophotometer (FTIR) on a surface (104) of a bonding portion with at least the resin member (105) in the aluminum-based metal member (103) and an absorbance of an absorption peak observed at 3400 cm.sup.−1 is defined as A.sub.1 and an absorbance at 3400 cm.sup.−1 of a straight line connecting an absorbance at 3800 cm.sup.−1 and an absorbance at 2500 cm.sup.−1 is defined as A.sub.0, an absorbance difference (A.sub.1−A.sub.0) is in a range of 0.03 or less.

A grain-oriented electrical steel sheet is a grain-oriented electrical steel sheet which does not have an inorganic coating containing forsterite as a main component and which includes: a base steel sheet containing a prescribed chemical component; a silicon-containing oxide layer provided on the base steel sheet; an iron-based oxide layer provided on the silicon-containing oxide layer; and a tension-insulation coating provided on the iron-based oxide layer, having a thickness of 1 to 3 μm, and containing phosphate and colloidal silica as main components. When the tension-insulation coating undergoes elemental analysis using a glow discharge optical emission spectrometry in a sheet thickness direction from a surface of the tension-insulation coating, a peak Si emission intensity satisfies a prescribed requirement.

[Problem] To propose a stainless steel structure excellent in hydrogen embrittlement resistance and corrosion resistance, being high in mass productivity, simple in device structure, low in equipment cost, and having a high cost advantage, and a method for manufacturing the same.

[Solving means] It is stainless steel having hydrogen embrittlement resistance and corrosion resistance, a surface of electrolytically polished stainless steel being coated with a film obtained by passivating a metal oxide formed by a wet process, wherein the film thickness of the film obtained by passivating the metal oxide formed by a wet process is greater than 100 nm. A hydrogen permeability ratio (film-formed product/film-unformed product) is equal to or less than 2.0×10.sup.−2, and a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test is equal to or greater than 0.8. It includes a polishing treatment step, a film-forming step, a curing treatment step, and a passivation treatment step, and the passivation treatment step consists of at least two or more independent passivation treatment steps.

A method of disposing a corrosion resistant system to a substrate may comprise applying a plating material to the substrate; forming a chemical conversion coating solution by combining a solvent, at least one corrosion inhibitive cation comprising at least one of zinc, calcium, strontium, magnesium, or aluminum, at least one corrosion inhibitive anion comprising at least one of phosphate, molybdate, or silicate, and a complexing agent; and applying the chemical conversion coating solution to the plating material on the substrate.

A method of disposing a corrosion resistant system to a substrate may comprise applying a plating material to the substrate; forming a chemical conversion coating solution by combining a solvent, at least one corrosion inhibitive cation comprising at least one of zinc, calcium, strontium, magnesium, or aluminum, at least one corrosion inhibitive anion comprising at least one of phosphate, molybdate, or silicate, and a complexing agent; and applying the chemical conversion coating solution to the plating material on the substrate.

An insulating coating treatment liquid for forming a chromium-free insulating coating on a surface of a grain-oriented electrical steel sheet, the insulating coating treatment liquid including at least one phosphate salt selected from phosphate salts of any of Mg, Ca, Ba, Sr, Zn, Al, and Mn and including colloidal silica and particles of a metal-element-containing compound. A content of the colloidal silica in terms of SiO.sub.2, on a solids basis, is 50 to 120 parts by mass, and a content of the particles of a metal-element-containing compound in terms of elemental metal is 5 to 60 parts by mass, per 100 parts by mass of the at least one phosphate salt, and the insulating coating treatment liquid has a thixotropic index (TI) of 1.00 or greater and 10.00 or less.

Methods of preparing 7xxx aluminum alloy products for adhesive bonding are disclosed. Generally, the methods include chemical and/or mechanically preparing a 7xxx aluminum alloy product to reduce the amount of magnesium oxides while maintaining any copper-containing intermetallic particles located proximal the surface of the 7xxx aluminum alloy product. After preparation, a functionalized layer may be produced thereon for adhesive bonding.