The present disclosure relates to a method of chemical pretreatment and selective phosphation of a composite metal construction comprising at least a portion made of aluminum and at least a portion made of zinc and optionally a further portion made of iron, which includes (I) treating the composite metal construction with an aqueous zinc phosphation composition that results in the formation of a surface-covering crystalline zinc phosphate layer and thenwith an intervening water rinse operation (II) applying an aqueous acidic passivation composition,

The present disclosure also relates to a corresponding zinc phosphation composition, to a concentrate for production thereof, to a corresponding composite metal construction and to a method of using thereof.

The present invention relates to an aqueous dispersion as a concentrate for the activation stage of phosphating of metal surfaces, containing a dispersed particulate constituent and a thickener, the particulate constituent containing, in addition to dispersed inorganic compounds of polyvalent metal cations, polymeric organic compounds as dispersing agents which are composed at least partially of styrene and/or an -olefin having no more than 5 carbon atoms and maleic acid, its anhydride and/or its imide, and which additionally comprise polyoxyalkylene units. The aqueous dispersion is further characterized by a D50 value above 10 m. The present invention also relates to a method for anti-corrosion pretreatment of the surfaces of a metal material, in particular for zinc phosphating.

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.

The invention relates to a method for zinc phosphating components so as to form layers, said components comprising surfaces made of steel with a high tolerance against aluminum dissolved in the zinc phosphating bath, wherein the precipitation of poorly soluble aluminum salts can be largely prevented. In the method, a process is used of activating the zinc surfaces by means of dispersions containing particulate hopeite, phosphophyllite, scholzite, and/or hureaulite, wherein the proportion of particulate phosphates in the activation process must be adapted to the quantity of free fluoride and dissolved aluminum in the zinc phosphation.

The invention relates to a method for zinc phosphating components comprising surfaces made of zinc in order to suppress the formation of insoluble phosphation constituents removably adhered to the zinc surfaces and thus further improve the adhesion of dip-paint coatings applied later. In the method, a process is used of activating the zinc surfaces by means of dispersions containing particulate hopeite, phosphophyllite, scholzite, and/or hureaulite, wherein the proportion of particulate phosphates in the activation process must be adapted to the quantity of free fluoride and dissolved silicon in the zinc phosphation.

Described herein is a method for phosphating of a metallic surface, wherein a metallic surface, optionally after cleaning and/or activation, is first treated with an acidic, aqueous, substantially nickel-free phosphating composition that includes zinc ions, manganese ions, iron(III) ions and phosphate ions, and is thereafter optionally rinsed and/or dried. Also described herein are a corresponding phosphating composition and a correspondingly phosphate-coated metallic surface.

A sheet steel, in particular strip-shaped blackplate, with a conversion coating which is prepared from components dissolved in water. The components are selected from the group of i) hexafluorotitanate, ii) zinc phosphate, iii) phosphoric acid, iv) a mixture of any of i) to iii), provided that the components i), ii) and iii) do not contain any organic ingredients.

The present invention relates to a process for the anti-corrosion pretreatment of a multiplicity of components in series, wherein each component in the series at least partly has surfaces of zinc and undergoes successive process steps for the deposition of iron and for zinc phosphation. In the process step for the deposition of iron, the coating layer to be established is at least 10 milligrams of elemental iron per square meter of the zinc surfaces. The zinc phosphation subsequent to this deposition of iron takes place by means of an acidic aqueous composition which in addition to zinc ions, phosphate ions and free fluoride also comprises a particulate constituent dispersed in water which is at least partly composed of hopeite, phosphophyllite, scholzite and/or hureaulite, and is provided by means of an aqueous dispersion of these crystalline solids that is stabilized with at least one polymeric organic compound.

Provided herein is a method for specifically adjusting the electrical conductivity of a conversion coating, wherein a metallic surface or a conversion-coated metallic surface is treated with an aqueous composition which comprises at least one kind of metal ions selected from the group consisting of the ions of molybdenum, copper, silver, gold, palladium, tin, and antimony and/or at least one electrically conductive polymer selected from the group consisting of the polymer classes of the polyamines, polyanilines, polyimines, polythiophenes, and polypryrols.

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.