A coating liquid for forming a metal oxide film, the coating liquid including: a metal source, which is at least one selected from the group consisting of inorganic salts, oxides, hydroxides, metal complexes, and organic acid salts; at least one alkali selected from the group consisting of organic alkalis and inorganic alkalis; and a solvent.

A coating liquid for forming a metal oxide film, the coating liquid including: a metal source, which is at least one selected from the group consisting of inorganic salts, oxides, hydroxides, metal complexes, and organic acid salts; at least one alkali selected from the group consisting of organic alkalis and inorganic alkalis; and a solvent.

A grain-oriented electromagnetic steel sheet exhibits excellent magnetic characteristics and excellent coating film adhesion after strain relieving annealing. The grain-oriented electromagnetic steel sheet includes: a steel sheet; a coating film layer A that is a ceramic coating film which is formed on the steel sheet and has an oxide content of less than 30% by mass; and a coating film layer B that is an insulating tension coating film which is arranged on the coating film layer A and contains an oxide. The binding energy of the 1s orbital of oxygen in the coating film layer B is higher than 530 eV; and tension applied to the steel sheet by the coating film layer B per a thickness of 1.0 m of the coating film layer B is 4.0 MPa/m or more.

A grain-oriented electromagnetic steel sheet exhibits excellent magnetic characteristics and excellent coating film adhesion after strain relieving annealing. The grain-oriented electromagnetic steel sheet includes: a steel sheet; a coating film layer A that is a ceramic coating film which is formed on the steel sheet and has an oxide content of less than 30% by mass; and a coating film layer B that is an insulating tension coating film which is arranged on the coating film layer A and contains an oxide. The binding energy of the 1s orbital of oxygen in the coating film layer B is higher than 530 eV; and tension applied to the steel sheet by the coating film layer B per a thickness of 1.0 m of the coating film layer B is 4.0 MPa/m or more.

A process for surface activation or depassivation of an article, in particular an alloy, by immersion of the alloy in an aqueous acid solution. The surface activation methods of the present invention can be performed during a relatively short period of time and achieve reductions in production costs and provide environmental friendliness as compared to prior art processes. In a further embodiment, after surface activation, the article is immersed in a second liquid that prevents re-formation of a passivating oxide layer on the surface of the article. In a further embodiment the surface-activated alloys are subjected to surface engineering by a process that infuses carbon or nitrogen through the surface at a temperature sufficiently low to suppress precipitation of carbides or nitrides.

A process for surface activation or depassivation of an article, in particular an alloy, by immersion of the alloy in an aqueous acid solution. The surface activation methods of the present invention can be performed during a relatively short period of time and achieve reductions in production costs and provide environmental friendliness as compared to prior art processes. In a further embodiment, after surface activation, the article is immersed in a second liquid that prevents re-formation of a passivating oxide layer on the surface of the article. In a further embodiment the surface-activated alloys are subjected to surface engineering by a process that infuses carbon or nitrogen through the surface at a temperature sufficiently low to suppress precipitation of carbides or nitrides.

There is provided a high-strength galvanized steel sheet and a relatively low-strength galvanized steel sheet that undergoes complex forming, a galvanized steel sheet that exhibits consistently excellent press formability and that generates no hazardous fumes during welding as well as a manufacturing method therefor. The galvanized steel sheet has an oxide layer on the surface, where the oxide layer has an average thickness of 20 nm or more, and the oxide layer contains 30 mg/m.sup.2 or more of Zn, 1.0 mg/m.sup.2 or more of S, and 50 mg/m.sup.2 or more and 1,000 mg/m.sup.2 or less of polyethylene particles having an average particle size of 5.0 m or less.

A chemical surface treatment method of a metal improves bonding of different materials in which first pores are formed in the surface of the metal and second pores are formed locally in the surfaces of the first pores by appropriately setting the number of repetitions of alkali treatment and acid treatment, the concentrations of treatment solutions, and treatment temperatures and times using the treatment solutions. The method includes performing the alkali treatment by immersing the metal in a base solution, so as to form first pores in a surface of the metal. The method further includes performing the acid treatment by immersing an alkali-treated result product in an acid solution, so as to form second pores locally in surfaces of the first pores.

A chemical surface treatment method of a metal improves bonding of different materials in which first pores are formed in the surface of the metal and second pores are formed locally in the surfaces of the first pores by appropriately setting the number of repetitions of alkali treatment and acid treatment, the concentrations of treatment solutions, and treatment temperatures and times using the treatment solutions. The method includes performing the alkali treatment by immersing the metal in a base solution, so as to form first pores in a surface of the metal. The method further includes performing the acid treatment by immersing an alkali-treated result product in an acid solution, so as to form second pores locally in surfaces of the first pores.

The corrosion resistance of conversion-coated metal substrate surfaces is further enhanced by treating such surfaces with aqueous mixtures of preformed reaction products obtained by reacting catechol compounds, such as dopamine or a dopamine salt, and functionalized co-reactant compounds, such as a polyethyleneimine.