This chemical conversion-treated steel sheet (10) has a chemical conversion treatment coating (12) upon a plating layer (17) of a steel sheet (11). The chemical conversion treatment coating (12) contains a fluororesin, a base resin which is a resin other than a fluororesin, metal flakes (13), and a chemical conversion treatment component. The content of the fluororesin in relation to the total quantity of resins is 3.0 mass % or more in terms of fluorine atoms, the content of the base resin in relation to 100 parts by mass of the fluororesin is 10 parts by mass or more, and the content of metal flakes (13) in the chemical conversion treatment coating (12) is more than 20 mass % but at most 60 mass %.

[Object] To provide a hot-dip zinc-based plated steel sheet excellent in coating film adhesiveness after hot pressing more conveniently. [Solution] A hot-dip zinc-based plated steel sheet according to the present invention includes: a hot-dip zinc-based plated steel sheet that is a base metal; and a surface treatment layer formed on at least one surface of the hot-dip zinc-based plated steel sheet, in which the surface treatment layer contains one or more oxides selected from zirconia, lanthanum oxide, cerium oxide, and neodymium oxide each having a particle size of more than or equal to 5 nm and less than or equal to 500 nm, in a range of more than or equal to 0.2 g/m.sup.2 and less than or equal to 2 g/m.sup.2 per one surface.

[Object] To provide a hot-dip zinc-based plated steel sheet excellent in coating film adhesiveness after hot pressing more conveniently. [Solution] A hot-dip zinc-based plated steel sheet according to the present invention includes: a hot-dip zinc-based plated steel sheet that is a base metal; and a surface treatment layer formed on at least one surface of the hot-dip zinc-based plated steel sheet, in which the surface treatment layer contains one or more oxides selected from zirconia, lanthanum oxide, cerium oxide, and neodymium oxide each having a particle size of more than or equal to 5 nm and less than or equal to 500 nm, in a range of more than or equal to 0.2 g/m.sup.2 and less than or equal to 2 g/m.sup.2 per one surface.

A method of activating a metal surface, such as a galvanized steel sheet, before a phosphating process, may involve bringing the metal surface into contact with an activating bath containing activating particles, which may be based on phosphate and/or titanium, dispersed in water. To alleviate or even eliminate the problems of poor adhesion of surface coatings to preferably electrolytically galvanized, phosphated metal strip, an additive that suppresses or at least slows agglomeration of the activating particles may be added to the activating bath. In some examples, polyethylene glycol (PEG) and/or sodium stearate may be added. Further, the particle size distribution of the activating particles present in the activating bath may be determined and the activating bath may be replaced or taken out of operation as a function of the particle size distribution of the activating particles.

A method of activating a metal surface, such as a galvanized steel sheet, before a phosphating process, may involve bringing the metal surface into contact with an activating bath containing activating particles, which may be based on phosphate and/or titanium, dispersed in water. To alleviate or even eliminate the problems of poor adhesion of surface coatings to preferably electrolytically galvanized, phosphated metal strip, an additive that suppresses or at least slows agglomeration of the activating particles may be added to the activating bath. In some examples, polyethylene glycol (PEG) and/or sodium stearate may be added. Further, the particle size distribution of the activating particles present in the activating bath may be determined and the activating bath may be replaced or taken out of operation as a function of the particle size distribution of the activating particles.

The present invention addresses the problem of providing, a metal surface treatment agent capable of exhibiting excellent corrosion resistance and excellent coating adhesion in painted metal materials; and a metal surface treatment method using the metal surface treatment agent. The problem is solved by a pretreatment agent that is used in a pretreatment of a chemical conversion treatment performed for forming a chemical conversion coating on/over a surface of a metal material, the pretreatment agent containing: a metal alkoxide (A) containing at least one metal element selected from zirconium, titanium, vanadium, and aluminum; and at least one sulfonic acid (B) selected from methanesulfonic acid, ethanesulfonic acid, hydroxymethanesulfonic acid, and hydroxyethanesulfonic acid. The problem is also solved by a chemical conversion treatment agent that contains a zirconium alkoxide (a) and a zirconium-containing ion supply source (b), and has a pH of 1.5 to 6.5.

The present invention addresses the problem of providing, a metal surface treatment agent capable of exhibiting excellent corrosion resistance and excellent coating adhesion in painted metal materials; and a metal surface treatment method using the metal surface treatment agent. The problem is solved by a pretreatment agent that is used in a pretreatment of a chemical conversion treatment performed for forming a chemical conversion coating on/over a surface of a metal material, the pretreatment agent containing: a metal alkoxide (A) containing at least one metal element selected from zirconium, titanium, vanadium, and aluminum; and at least one sulfonic acid (B) selected from methanesulfonic acid, ethanesulfonic acid, hydroxymethanesulfonic acid, and hydroxyethanesulfonic acid. The problem is also solved by a chemical conversion treatment agent that contains a zirconium alkoxide (a) and a zirconium-containing ion supply source (b), and has a pH of 1.5 to 6.5.

The invention relates to a method for the anti-corrosion pre-treatment of a plurality of components in series, in which the components of the series are at least partially formed of iron and/or steel, and in which the components of the series each initially undergo a first conversion stage, followed by a rinsing stage and a subsequent second conversion stage, wherein, in the conversion stages, respective acidic aqueous conversion solutions based on compounds of the elements Zr and/or Ti dissolved in water are brought into contact with the components, and, additionally, copper ions are contained in the conversion solution for the second stage.

The invention relates to a method for the anti-corrosion pre-treatment of a plurality of components in series, in which the components of the series are at least partially formed of iron and/or steel, and in which the components of the series each initially undergo a first conversion stage, followed by a rinsing stage and a subsequent second conversion stage, wherein, in the conversion stages, respective acidic aqueous conversion solutions based on compounds of the elements Zr and/or Ti dissolved in water are brought into contact with the components, and, additionally, copper ions are contained in the conversion solution for the second stage.

Described herein is a method for treatment of at least one surface of a substrate at least partially made of aluminum and/or an aluminum alloy, including at least a step of contacting said surface with an acidic aqueous composition (A) including one or more metal compounds (M) selected from the group of titanium compounds, zirconium compounds, and hafnium compounds and one or more linear polymers (P) containing (m1) N,N-dimethyl (meth)acryl amide, (m2) vinylphosphonic acid, and (m3) (meth)acrylic acid in form of their polymerized monomeric units, the one or more linear polymers (P) being included in the acidic aqueous composition (A) in an amount of 50 to 5000 ppm. Also described herein is an acidic aqueous composition (A), a master batch to produce the acidic aqueous composition (A), a method of using the acidic aqueous composition (A) for treating surfaces, and substrates comprising the treated surfaces.