The present invention relates to a process for anticorrosion pretreatment of multiple components in series, each component in the series at least partly comprises metal surfaces of zinc, iron and/or aluminum and undergoes a zinc phosphating step in which the component is contacted with an acidic aqueous composition containing an amount of an activating aid sufficient to ensure a layer weight below 5.5 g/m.sup.2 on a cleaned, untreated hot-dip galvanized steel surface (Z), wherein the activating aid is based on a water-dispersed particulate constituent at least partly selected from hopeite, phosphophyllite, scholzite and/or hureaulite, and at least one polymeric organic compound; and further relates to acidic aqueous zinc phosphating compositions obtainable by adding a particular amount of a colloidal aqueous solution containing the dispersed particulate constituent to an acidic aqueous composition containing zinc ions, phosphate ions and free fluoride.

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.

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.

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 present invention relates to a method for zinc phosphating of metal surfaces using a colloidal aqueous solution as activation stage, a zinc phosphate layer having a layer weight of less than 2.0 g/m.sup.2 being deposited on surfaces of zinc in the method step following activation. The activation stage is based on a colloidal aqueous solution containing a dispersed particulate constituent, the particulate constituent containing, in addition to dispersed inorganic compounds of phosphates of polyvalent metal cations, a polymeric organic compound as a dispersing agent that is composed at least partially of styrene and/or an α-olefin having no more than 5 carbon atoms, the polymeric organic compound additionally comprising units of maleic acid, their anhydride and/or their imide and the polymeric organic compound additionally comprising polyoxyalkylene units.

The invention relates to a process for coating metal surfaces with an aqueous composition in the form of a solution or in the form of a dispersion, the composition comprising at least one phosphate, at least 3 g/l of at least one titanium or/and zirconium compound and at least one complexing agent, and also to corresponding aqueous compositions. The coatings prepared thereby have very good bare corrosion protection in the NSS salt spray test and in the condensation-water/constant-climate test

The invention relates to a process for producing a corrosion-inhibiting coating for substrates having a surface consisting of zinc, magnesium, aluminum or one of their alloys, wherein the surface to be treated is brought into contact in direct succession with two aqueous treatment solutions containing chromium(III) ions, metal ions of the substrate surface to be treated and at least one complexing agent. The first treatment solution has a pH in the range from 1.0 to 4.0, while the second treatment solution has a pH of from 3.0 to 12.0. The process of the invention produces a smaller amount of wastewater polluted with heavy metals.

The present invention relates to a method for phosphating metal surfaces in a layer-forming manner using a colloidal aqueous solution as an activation stage, containing a dispersed particulate constituent, the particulate constituent containing, in addition to dispersed inorganic compounds of phosphates of polyvalent metal cations, polymeric organic compounds as dispersing agents which are composed at least partially of styrene and/or an α-olefin having no more than 5 carbon atoms and are composed at least partially of maleic acid, its anhydride and/or its imide, the polymeric organic compounds additionally comprising polyoxyalkylene units. The cleaning and rinsing stages preceding the activation stage as well as the activation stage itself can be carried out using service water in a resource-saving manner without any loss of activation performance, the colloidal aqueous solution containing at least 0.5 mmol/L of alkaline-earth metal ions dissolved in water.

A method for phosphating metal surfaces in a layer-forming manner using a colloidal aqueous solution as an activation stage containing a dispersed particulate constituent, the particulate constituent containing dispersed inorganic compounds of phosphates of polyvalent metal cations; plus polymeric organic compounds as dispersing agents, which are composed at least partially of styrene and/or an α-olefin having no more than 5 carbon atoms and are composed at least partially of maleic acid, its anhydride and/or its imide, the polymeric organic compounds additionally comprising polyoxyalkylene units. In the activation stage of the method according to the invention, the addition of condensed phosphates can be dispensed with such that the content of dissolved condensed phosphates in the colloidal aqueous solution is less than 0.25, based on the phosphate content in the particulate constituent thereof, in each case based on the element P.

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.