A method for the manufacture of a substrate provided with a chromium VI-free and a cobalt-free passivation by the application of a first acidic passivation and a second alkaline passivation, containing a silane-modified and/or a siloxane modified silicate, with which an improved protection against corrosion is achieved, an aqueous, acidic composition for passivating and a passivated substrate, and a device for applying the passivation.

The present invention relates to an acidic aqueous composition for treating of zirconium-pretreated metal-based substrate surfaces such as steel metals or aluminium surfaces, a process for treating the substrate surfaces with the composition and the use of the composition as post-treatment of zirconium-pretreated metal-based substrate surfaces for subsequent electrocoating of the surfaces to increase corrosion resistance of said metal-based surfaces prior to electro-coating (e-coat) applications and increases detergent and chemical resistance of treated surfaces used in the white goods industry. The acidic aqueous composition comprises trivalent chromium ions; and hexafluorozirconate ions; characterized in that the source of trivalent chromium ions is a trivalent chromium nitrate salt.

[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.

The present invention is directed towards an aqueous alkaline cleaner composition comprising: an iron cation, a molybdenum cation, a cobalt cation, or combinations thereof; and an alkaline component; wherein the pH of the aqueous alkaline composition is at least 10, and the aqueous alkaline composition includes no more than 50 ppm of phosphate. Also disclosed are treatment systems comprising an aqueous alkaline composition for treating at least a portion of a substrate, and a pretreatment composition for treating at least a portion of a substrate. Also disclosed are substrates treated according to the disclosed treatment systems.

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 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.

Provided is a surface processing method for an aluminum heat exchanger, by which odor can be suppressed and which enables the aluminum heat exchanger to exhibit corrosion resistance and moisture resistance that are excellent to conventional art. The surface processing method for an aluminum heat exchanger uses a chemical conversion treatment agent that includes: one, or two or more type of a metallic element (A) selected from a group comprising of zirconium, titanium, and hafnium; vanadium element (B); and a resin (C). The resin (C) includes a polyvinyl alcohol resin (C1). The ratio (Wa/Wb) of the weight-based total content (Wa) of the metallic element (A) relative to the weight-based content (Wb) of vanadium element (B) is 0.1-15, and the ratio ((Wa+Wb)/Wc1) of the weight-based total content (Wa+Wb) of the metallic element (A) and vanadium element (B) relative to the weight-based total content (Wc1) of the polyvinyl alcohol resin (C1) is 0.25-15.

Disclosed is a system for treating a surface of a multi-metal article. The system includes first and second compositions for contacting at least a portion of the surface. The first composition includes phosphate ions and zinc ions and is substantially free of fluoride. The second composition includes a lanthanide series metal cation and an oxidizing agent. Methods of treating a multi-metal article using the system also are disclosed. Also disclosed are substrates treated with the system and method.

A component (1) is disclosed which has a black oxide layer (10), wherein metallic additive elements (4) are incorporated in the structure of the black oxide layer (10). Furthermore, a method for manufacturing such a component (1) is disclosed, said method comprising the steps of: depositing metallic additive elements (4) on the component (1) and immersing the component (1) with the deposited metallic additive elements (4) in a black oxide solution (6), wherein the metallic additive elements (4) are incorporated into the structure of the black oxide layer (10).

A component (1) is disclosed which has a black oxide layer (10), wherein metallic additive elements (4) are incorporated in the structure of the black oxide layer (10). Furthermore, a method for manufacturing such a component (1) is disclosed, said method comprising the steps of: depositing metallic additive elements (4) on the component (1) and immersing the component (1) with the deposited metallic additive elements (4) in a black oxide solution (6), wherein the metallic additive elements (4) are incorporated into the structure of the black oxide layer (10).