The invention relates to polyfunctional polymers suitable in particular for the treatment of metal surfaces (metal finishing) and comprising: monomer units u1 bearing phosphonic acid functions; monomer units u2 bearing amine functions; and optionally monomer units u3 bearing alcohol units —OH.

The present invention provides a surface treatment liquid for metal having a sufficiently high film-forming property. The present invention relates to a surface treatment liquid for metal comprising an azole silane coupling agent, the surface treatment liquid further comprises (A) an organic acid ion having one to three acidic groups in one molecule; (B) an inorganic acid (or mineral acid) ion; (C) an alkali metal ion and/or an ammonium ion; and (D) a copper ion.

Metallic substrate treatment methods and articles comprising a phosphonate functionalized layer are provided. The method comprises contacting a metallic substrate comprising at least one of aluminum and an aluminum alloy with a fluid to form a phosphonate functionalized layer on at least a region of the metallic substrate. The fluid comprises at least one of a phosphonate containing acid and a derivative thereof. At least one of the phosphonate containing acid and the derivative thereof comprises a pKa of a first acidic proton. The fluid comprises a pH at least 0.5 pH value greater than the pKa of the first acidic proton. The article comprises a metallic substrate comprising aluminum or an aluminum alloy and a phosphonate functionalized layer on at least a region of the metallic substrate.

A coating agent for forming a grain-oriented electrical steel sheet coating able to form an aluminum borate coating high in adhesion and large in tension and a method for manufacturing the grain-oriented electrical steel sheet are provided. The coating agent for forming a grain-oriented electrical steel sheet coating of the present invention comprises an aluminum source containing aluminum oxide and/or an aluminum oxide precursor compound, a boron source containing a borate of an alkali metal, and silicon oxide and/or a silicon oxide precursor in an amount, converted to silicon oxide, of 5 mass % or more and 10 mass % or less with respect to a total solids concentration of the aluminum source and boron source, the aluminum source and the boron source contained so that, by molar ratio, Al/B: 0.5 to 2.0, a solids concentration of a total of the aluminum source and the boron source being 20 mass % or more and 38 mass % or less, and pH being 2.0 or more and 6.0 or less.

To improve oxidation and corrosion resistance of stainless steel, it is not necessary to apply suspensions containing nanoparticles of rare earth metal oxides. Rare earth metal nitrates or acetates in aqueous solution improve the oxidation and corrosion resistance of stainless steels when applied to the surface of the steels. Further oxidation and corrosion resistance can be provided by the addition of chromium or aluminum acetate, nitrate, or sulfate to the rare earth metal nitrate or acetate aqueous solutions before application to the steel.

A steel substrate coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer—includes at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is provided.

A steel substrate coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer—includes at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is provided.

A steel substrate is provided, coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer including at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is also provided.

A steel substrate is provided, coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer including at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is also provided.

Treating carbon steel tubing includes contacting the carbon steel tubing with a first treatment solution including a salt; corroding the carbon steel tubing with the salt to yield a corroded surface on the carbon steel tubing; contacting the corroded surface on the carbon steel tubing with a second treatment solution comprising sulfide ions; and forming an iron sulfide layer on the corroded surface of the carbon steel tubing by chemically bonding the sulfide ions in the second treatment solution with iron in the carbon steel tubing. In some cases, the first treatment solution also includes sulfide ions, and the iron sulfide layer is formed by contacting the carbon steel tubing with the first treatment solution.