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.

A composition for a phosphate film of a Zn electric-plated steel sheet may comprise zinc (Zn), nickel (Ni), and manganese (Mn), wherein a content of Mn is 6 to 8 wt %.

Disclosed is an activating rinse for treating at least a portion of a substrate, comprising a dispersion of metal phosphate particles having a D.sub.90 particle size of no greater than 10 μm, wherein the metal phosphate comprises divalent or trivalent metals or combinations thereof; a dispersant; and a metal sulfate salt. Methods of treating a substrate with the activating rinse also are disclosed. Optionally, substrates treated with the activating rinse also are disclosed.

Disclosed is a phosphate coating, comprising: a phosphate portion, wherein the phosphate portion comprises pores, wherein the pores are at least partially filled with a corrosion inhibition sealant, wherein the corrosion inhibition sealant comprises: a base, wherein the base comprises a matrix and a metal within the matrix, wherein the metal within the matrix comprises aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy, or a combination thereof and an inhibitor mixed within the base, wherein the inhibitor comprises zinc molybdate, magnesium metasilicate, trivalent chromium, tungstenate, a metal phosphate silicate, or a combination thereof.

Described herein is a water-based, alkaline cleaner concentrate for producing a cleaner for metallic surfaces, the concentrate including a) at least one (meth)acrylic acid homopolymer having a weight-average molar mass in the range from 3 000 to 19 000 g/mol and b) at least one (meth)acrylic acid copolymer having a weight-average molar mass in the range from 50 000 to 100 000 g/mol. Also described herein are a corresponding cleaner for metallic surfaces with reduced pickling erosion, a process for anticorrosive treatment of metallic surfaces that includes a corresponding cleaning step, a metallic surface obtained by the process, and a method of use thereof in the sector of the metalworking industries.

Described herein is a method for treatment of at least one surface of a metal containing substrate including at least contacting the surface with an aqueous acidic Ni-free composition (A) including at least zinc cations, manganese cations, and phosphate anions to form a conversion coating on the surface and contacting the formed coating with an aqueous Ni-free composition (B) including one or more linear polymers (P) containing at least vinyl phosphonic acid, (meth)acrylic acid, and hydroxyethyl- and/or hydroxypropyl (meth)acrylate in form of their polymerized monomeric units. Also described herein is the composition (B), a master batch to produce the composition (B), a kit-of-parts including both compositions (A) and (B), a kit-of-parts including respective master batches to produce both compositions (A) and (B), and a coated substrate obtainable by the method described herein.

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.

Described herein is a method for treatment of at least one surface of a metal containing substrate including contacting the surface with an aqueous acidic Ni-free composition (A) including at least zinc cations, manganese cations, and phosphate anions to form a conversion coating on the surface, and contacting the formed coating with an aqueous Ni-free composition (B) including one or more linear polymers (P) containing vinyl phosphonic acid and (meth)acrylic acid in form of their polymerized monomeric units. Also described herein is a composition (B) as such, a master batch to produce the composition (B), a kit-of-parts including both compositions (A) and (B), a kit-of-parts including respective master batches to produce both compositions (A) and (B), and a coated substrate obtainable by the method described herein.

An aqueous passivation composition, having a pH of less than 3, comprising: i) a source of trivalent chromium ions; ii) at least one -hydroxycarboxylic acid having general formula (I): R.sub.1CH(OH)COOH (I); wherein: R.sub.1 represents a hydrogen atom, a C1-C4 alkyl group, a C2-C6 alkenyl group, a C1-C6 alkoxy group, a C.sub.3-C.sub.6 cycloalkyl group or a C6-C10 aryl group; iii) phosphoric acid; iv) at least one water-soluble polyphosphonic acid or a water-soluble salt thereof, said polyphosphonic acid having general formula (II): Z[PO(OH).sub.2].sub.n (II); in which: n is at least 2; and Z is a connecting organic moiety having an effective valency of n, said polyphosphonic acid including at least two phosphonic groups separated by an alkylene bridge having 1 or 2 carbon atoms (C.sub.1-C.sub.2 alkylene); and v) at least one divalent metal cation;
wherein said composition is substantially free of: nitrate and fluoride anions, and hexavalent chromium.

The coating film-forming composition is a solution of pH 4 to 10 and includes an aromatic compound having an amino group and an aromatic ring in one molecule, a polybasic acid having two or more carboxy groups, and an oxidizing agent. As the oxidizing agent, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, persulfuric acid, percarbonic acid, hydrogen peroxide, organic peroxides, or the like is used. The aromatic compound preferably contains a nitrogen-containing aromatic ring, and more preferably contains a primary amino group or a secondary amino group. The coating film-forming composition is used for, for example, forming a coating film on surface of a metal member.