The invention relates to use of an aqueous composition for pretreating can body stock, whereby an inorganic-organic conversion layer is formed, which effects outstanding sliding behavior of the shaped can body stock and in addition offers an outstanding holding primer for subsequent coating. The invention comprises a process in which can body stock which is deep-drawn to form a half-open can cylinder, before further shaping processes, is contacted with an acidic aqueous composition which contains water-soluble inorganic compounds of Zr, Ti, Si, Hf or Ce, water-soluble polymers having carboxyl groups or hydroxyl groups and also a dispersed wax. Both outer and inner surfaces of metallic can cylinders can be pretreated in the process. The invention also relates to an acidic aqueous composition for use in the pretreatment process, which contains water-soluble polymers selected from condensation products of glycoluril and aldehydes.

Described herein is a method for substantially nickel-free phosphating of a metallic surface, wherein a metallic surface, optionally after cleaning and/or activation, is first treated with an acidic aqueous phosphating composition that includes zinc ions, manganese ions, and phosphate ions, and is optionally rinsed and/or dried, and is thereafter treated with an aqueous after-rinse composition that includes at least one kind of metal ion selected from the group consisting of the ions of molybdenum, copper, silver, gold, palladium, tin, antimony, titanium, zirconium, and hafnium and/or at least one polymer selected from the group consisting of the polymer classes of the polyamines, polyethyleneamines, polyanilines, polyimines, polyethyleneimines, polythiophenes, and polypryroles and also mixtures and copolymers thereof, with both the phosphating composition and the after-rinse composition being substantially nickel-free.

An object of the present invention is to provide a method for forming a multilayer coating film, the method capable of achieving excellent finished appearance and excellent corrosion resistance without affecting electrodeposition coatability even when a part or all of the water-washing step is omitted after chemical conversion treatment, and to provide a coated article. The invention provides a method for forming a multilayer coating film, comprising forming a chemical conversion coating film and an electrodeposition coating film on a metal substrate by Step 1 of immersing a metal substrate in a chemical conversion treatment solution to form a chemical conversion coating film, and Step 2 of omitting a part or all of the water-washing step, and performing electrodeposition coating on the metal substrate using a cationic electrodeposition coating composition to form an electrodeposition coating film, wherein the chemical conversion treatment solution contains less than 500 ppm of sodium ions on a mass basis, and hexafluorozirconic acid. The chemical conversion treatment solution preferably contains no less than 5 ppm to less than 50 ppm of sodium ions, no less than 5 ppm to less than 90 ppm of calcium ions, less than 100 ppm of potassium ions, and less than 90 ppm of magnesium ions, on a mass basis; and is used continuously.

An object of the present invention is to provide a method for forming a multilayer coating film, the method capable of achieving excellent finished appearance and excellent corrosion resistance without affecting electrodeposition coatability even when a part or all of the water-washing step is omitted after chemical conversion treatment, and to provide a coated article. The invention provides a method for forming a multilayer coating film, comprising forming a chemical conversion coating film and an electrodeposition coating film on a metal substrate by Step 1 of immersing a metal substrate in a chemical conversion treatment solution to form a chemical conversion coating film, and Step 2 of omitting a part or all of the water-washing step, and performing electrodeposition coating on the metal substrate using a cationic electrodeposition coating composition to form an electrodeposition coating film, wherein the chemical conversion treatment solution contains less than 500 ppm of sodium ions on a mass basis, and hexafluorozirconic acid. The chemical conversion treatment solution preferably contains no less than 5 ppm to less than 50 ppm of sodium ions, no less than 5 ppm to less than 90 ppm of calcium ions, less than 100 ppm of potassium ions, and less than 90 ppm of magnesium ions, on a mass basis; and is used continuously.

The present invention relates to a method for substantially nickel-free phosphating of a metallic surface, wherein a metallic surface is treated one after the other with the following compositions: i) with an alkaline, aqueous cleaner composition which comprises at least one water-soluble silicate, and ii) with an acidic, aqueous, substantially nickel-free phosphating composition which comprises zinc ions, manganese ions and phosphate ions.

The invention also relates to the above cleaner composition itself and also to a metallic surface phosphate-coated by the above method, and to the use of said surface.

A steel sheet for a fuel tank includes: a ZnNi alloy plated layer which is placed on one surface or each of both surfaces of a base metal and formed on at least one surface; and an inorganic chromate-free chemical conversion coating film which is placed over the ZnNi alloy plated layer. The ZnNi alloy plated layer has a crack starting from an interface between the ZnNi alloy plated layer and the inorganic chromate-free chemical conversion coating film and reaching an interface between the ZnNi alloy plated layer and the steel sheet, and a water contact angle on a surface of the inorganic chromate-free chemical conversion coating film is more than or equal to 50 degrees.

A composite can include a substrate and a conversion coating overlying the substrate and comprising at least one of a zirconium oxide, a hafnium oxide, or a combination thereof. The conversion coating can be formed from a zirconia or hafnia-based complex obtained by reacting at least one of a zirconium ion source, a hafnium ion source, or a combination thereof, with a chelating compound in a reaction and another chelating compound in another reaction.

A chemical treatment steel sheet includes a steel sheet, an FeSn alloy layer which is formed on at least one surface of the steel sheet, a Sn layer which is formed on the FeSn alloy layer and contains Sn in which a total amount of Sn contained in the FeSn alloy layer and the Sn layer is 0.10 to 30.0 g/m.sup.2, and a chemical treatment layer which is formed on the Sn layer and contains a Zr compound in which an amount of Zr contained therein is 1.0 to 150 mg/m.sup.2, a phosphate compound in an amount of P contained therein is 1.0 to 100 mg/m.sup.2 and an Al compound in an amount of Al contained therein is 0.10 to 30.0 mg/m.sup.2.

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 %.

A problem to be solved by the present invention is to provide a method for forming a multilayer coating film, the method being capable of achieving excellent finished appearance and excellent corrosion resistance without affecting electrodeposition coatability even when a part or all of the water-washing step is omitted after chemical conversion treatment, and to provide a coated article. The invention provides a method for forming a multilayer coating film, comprising forming a chemical conversion coating film and an electrodeposition coating film on a metal substrate by Step 1 of immersing a metal substrate in a chemical conversion treatment solution to form a chemical conversion coating film, and Step 2 of omitting a part or all of the water-washing step, and performing electrodeposition coating on the metal substrate using a cationic electrodeposition coating composition to form an electrodeposition coating film, wherein when the electrodeposition coating is performed in Step 2, the solution adhered to and/or deposited on the metal substrate has an electrical conductivity of less than 10,000 S/cm.