The invention relates to a method for preparing a metal sheet (1) comprising at least the steps: providing a steel substrate (3) having two faces (5), at least one of which is coated with a metal coating (7) comprising at least 40% by weight of zinc, applying on the outer surface (15) of the metal coating (7) an aqueous solution comprising an amino acid, and the metal sheet which may be obtained.

The invention relates to a method for preparing a metal sheet (1) comprising at least the steps: providing a steel substrate (3) having two faces (5), at least one of which is coated with a metal coating (7) comprising at least 40% by weight of zinc, applying on the outer surface (15) of the metal coating (7) an aqueous solution comprising an amino acid, and the metal sheet which may be obtained.

The present invention provides a chemical conversion liquid for zinc or zinc alloy bases, which contains 2-200 mmol/L of trivalent chromium ions, 1-300 mmol/L of zirconium ions and at least one component selected from among fluorine ions, a water-soluble carboxylic acid and a salt thereof, and which does not contain Co ions and hexavalent chromium ions.

The present invention provides a chemical conversion liquid for zinc or zinc alloy bases, which contains 2-200 mmol/L of trivalent chromium ions, 1-300 mmol/L of zirconium ions and at least one component selected from among fluorine ions, a water-soluble carboxylic acid and a salt thereof, and which does not contain Co ions and hexavalent chromium ions.

Provided are a treatment liquid for a black trivalent chromium conversion coating, and a trivalent chromium-containing water-soluble liquid for finishing treatment, achieving excellent corrosion resistance and scratch resistance without containing a cobalt compound, with high stability and adequate consideration for environmental issues; and a method for treating a metal substrate using the same. The treatment liquid for a black trivalent chromium conversion coating on the surface of a metal substrate contains a trivalent chromium compound, two or more organic acids or organic acid salts, or one or more organic sulfur compounds, and nitrate ions, and contains no cobalt compound.

Provided are a treatment liquid for a black trivalent chromium conversion coating, and a trivalent chromium-containing water-soluble liquid for finishing treatment, achieving excellent corrosion resistance and scratch resistance without containing a cobalt compound, with high stability and adequate consideration for environmental issues; and a method for treating a metal substrate using the same. The treatment liquid for a black trivalent chromium conversion coating on the surface of a metal substrate contains a trivalent chromium compound, two or more organic acids or organic acid salts, or one or more organic sulfur compounds, and nitrate ions, and contains no cobalt compound.

A sliding member includes, on a surface of a metal substrate, a surface-treated layer including a zinc-electroplated layer, a chemical conversion-treated layer, and a topcoat layer sequentially stacked on the metal substrate. The chemical conversion-treated layer includes chromium and oxygen. The topcoat layer includes at least one material selected from the group consisting of a silica compound, acrylic resin, polyurethane resin, epoxy resin, phenol resin, and melamine resin. A method of manufacturing the sliding member includes a step of forming, on a surface of the chemical conversion-treated layer, the topcoat layer including at least one material selected from the group consisting of a silica compound, acrylic resin, polyurethane resin, epoxy resin, phenol resin, and melamine resin.

A home appliance chemically resistant to peroxide degradation. The home appliance includes a metal substrate disposed therein that includes a metal substrate having a bulk portion and a coating layer contacting a surface of the bulk portion. The coating layer includes a ternary metal oxide compound, a metal alloy, an intermetallic compound, or a combination thereof. The ternary metal oxide compound, the metal alloy or the intermetallic compound is (a) unreactive with hydrogen peroxide or (b)(1) reactive with hydrogen peroxide to form one or more metal oxides unreactive with hydrogen peroxide or reactive with hydrogen peroxide to form one or more metal oxides unreactive with hydrogen peroxide and/or (b)(2) reactive with hydrogen peroxide to form one or more elemental metals reactive with hydrogen peroxide to form one or more metal oxides.

A home appliance chemically resistant to peroxide degradation. The home appliance includes a metal substrate disposed therein that includes a metal substrate having a bulk portion and a coating layer contacting a surface of the bulk portion. The coating layer includes a ternary metal oxide compound, a metal alloy, an intermetallic compound, or a combination thereof. The ternary metal oxide compound, the metal alloy or the intermetallic compound is (a) unreactive with hydrogen peroxide or (b)(1) reactive with hydrogen peroxide to form one or more metal oxides unreactive with hydrogen peroxide or reactive with hydrogen peroxide to form one or more metal oxides unreactive with hydrogen peroxide and/or (b)(2) reactive with hydrogen peroxide to form one or more elemental metals reactive with hydrogen peroxide to form one or more metal oxides.

The chemical conversion treatment liquid according to the present invention, which is cobalt-free and is capable of forming a chemical conversion film having excellent corrosion resistance, contains a water-soluble trivalent chromium-containing substance, a water-soluble titanium-containing substance, and a water-soluble lactic acid-containing substance as essential components and may optionally contain a component at least a part of which is any of a water-soluble glycolic acid-containing substance and a water-soluble ineffective organic acid-containing substance. The water-soluble ineffective organic acid-containing substance is a water-soluble organic acid-containing substance based on an ineffective organic acid that is an organic acid other than lactic acid and other than glycolic acid. When the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and does not contain the water-soluble ineffective organic acid-containing substance, a titanium-equivalent molar concentration CTi of the water-soluble titanium-containing substance, a chromium-equivalent molar concentration CCr of the water-soluble trivalent chromium-containing substance, and a lactic acid-equivalent molar concentration CLc of the water-soluble lactic acid-containing substance satisfy the following Expressions (1) to (3):
CTi/CCr0.5(1);
CLc/(CTi+CCr)0.40(2); and
CLc/CTi2.6(3).