Abstract: The present invention relates to a very specific electroplating bath for depositing a black chromium layer, and a respective method for electroplating such a layer. The electroplating bath comprises two specific groups of compounds defined as (D) and (E), present in a particularly defined molar ratio ranging from 0.9 to 2.65, based on (E):(D). The black chromium layer is excellently suited for decorative purposes.

Abstract: The present invention relates to a black plated substrate comprising a base-substrate and deposited thereon a layer stack, wherein the layer stack comprises a black chromium plating layer comprising on its surface a conversion layer having a depth of 30 nm or more, characterized in that the conversion layer does not comprise metallic chromium or comprises metallic chromium only up to 2 at.-%, based on the element chromium and the total number of chromium atoms in the conversion layer.

Abstract: The present invention relates to a method for electrodepositing a dark chromium layer on a substrate and a substrate having at least one side fully covered with a dark chromium layer. The method includes utilizing an aqueous trivalent chromium electroplating bath comprising colloidal particles and a step of treating the substrate with a rinse liquid having a temperature of 50° C. or more.

Abstract: The present invention relates to a very specific electroplating bath for depositing a black chromium layer, a respective method thereof, and a respective substrate with said black chromium layer thereon. The substrate comprising said black chromium layer is excellently suited for decorative purposes.

Abstract: A method for post-treatment of a chromium finish surface to improve corrosion resistance comprising a) providing a substrate having a chromium finish surface, and at least one intermediate layer between the chromium finish surface and the substrate, selected from the group consisting of nickel, nickel alloys, copper and copper alloys, wherein the chromium finish surface is a surface of a trivalent chromium plated layer, obtained by electroplating the substrate, having the at least one intermediate layer, in a plating bath, the plating bath comprising chromium (III) ions; b) contacting the chromium finish surface with an aqueous solution, comprising a permanganate, at least one compound which is selected from a phosphorus-oxygen compound, a hydroxide, a nitrate, a borate, boric acid, a silicate, or a mixture of two or more of these compounds; c) forming a transparent corrosion protection layer onto the chromium finish surface during step b.

Abstract: A method for post-treatment of a chromium finish surface to improve corrosion resistance comprising a) providing a substrate having a chromium finish surface, and at least one intermediate layer between the chromium finish surface and the substrate, selected from the group consisting of nickel, nickel alloys, copper and copper alloys, wherein the chromium finish surface is a surface of a trivalent chromium plated layer, obtained by electroplating the substrate, having the at least one intermediate layer, in a plating bath, the plating bath comprising chromium (III) ions; b) contacting the chromium finish surface with an aqueous solution, comprising a permanganate, at least one compound which is selected from a phosphorus-oxygen compound, a hydroxide, a nitrate, a borate, boric acid, a silicate, or a mixture of two or more of these compounds; c) forming a transparent corrosion protection layer onto the chromium finish surface during step b.

Abstract: A method for post-treatment of a chromium finish surface to improve corrosion resistance comprising a) providing a substrate having a chromium finish surface, and at least one intermediate layer between the chromium finish surface and the substrate, selected from the group consisting of nickel, nickel alloys, copper and copper alloys, wherein the chromium finish surface is a surface of a trivalent chromium plated layer, obtained by electroplating the substrate, having the at least one intermediate layer, in a plating bath, the plating bath comprising chromium (III) ions; b) contacting the chromium finish surface with an aqueous solution, comprising a permanganate, at least one compound which is selected from a phosphorus-oxygen compound, a hydroxide, a nitrate, a borate, boric acid, a silicate, or a mixture of two or more of these compounds; c) forming a transparent corrosion protection layer onto the chromium finish surface during step b.

Abstract: Method for increasing corrosion resistance of substrate including an outermost chromium alloy layer, including (i) providing substrate comprising an outermost layer, the layer having color space defined by CIELAB with lightness L* of 79 or more, including oxygen and carbon, and including iron in amount up to 1 atom-%, (ii) providing an aqueous, acidic passivation solution, the solution including trivalent chromium ions, phosphate ions, one or more than one organic acid anion, (iii) contacting the substrate with the passivation solution and passing electrical current between the substrate as cathode and an anode in the passivation solution wherein a passivation layer is deposited onto the outermost layer, wherein in step (i) the outermost layer is electrolytically deposited from aqueous, acidic deposition composition, the composition including trivalent chromium ions, at least one organic acid comprising an isothiureido moiety and/or salts thereof, and chloride ions in amount of 0 wt-% to 0.1 wt-%.

Abstract: A method for electrolytically passivating an outermost chromium or chromium alloy layer to increase corrosion resistance thereof, including steps of (i) providing a substrate comprising said outermost chromium or chromium alloy layer, (ii) providing or manufacturing an aqueous, acidic passivation solution comprising trivalent chromium ions, phosphate ions, one or more organic acid residue anion, (iii) contacting the substrate with the passivation solution and passing an electrical current between the substrate as a cathode and an anode in the passivation solution such that a passivation layer is deposited onto the outermost layer, wherein the trivalent chromium ions are obtained by chemically reducing hexavalent chromium in presence of phosphoric acid and at least one reducing agent, with the proviso that during or after the chemical reducing the one or more than one organic acid residue anion is present for the first time in the passivation solution.

Abstract: Method for increasing corrosion resistance of substrate including an outermost chromium alloy layer, including (i) providing substrate comprising said outermost layer, the layer having color space defined by CIELAB with lightness L* of 79 or more, including oxygen and carbon, and including iron in amount up to 1 atom-%, (ii) providing an aqueous, acidic passivation solution, the solution including trivalent chromium ions, phosphate ions, one or more than one organic acid anion, (iii) contacting the substrate with the passivation solution and passing electrical current between the substrate as cathode and an anode in the passivation solution wherein a passivation layer is deposited onto the outermost layer, wherein in step (i) the outermost layer is electrolytically deposited from aqueous, acidic deposition composition, the composition including trivalent chromium ions, at least one organic acid comprising an isothiureido moiety and/or salts thereof, and chloride ions in amount of 0 wt-% to 0.1 wt-%.

Abstract: A method for electrolytically passivating an outermost chromium or chromium alloy layer to increase corrosion resistance thereof, including steps of (i) providing a substrate comprising said outermost chromium or chromium alloy layer, (ii) providing or manufacturing an aqueous, acidic passivation solution comprising trivalent chromium ions, phosphate ions, one or more organic acid residue anion, (iii) contacting the substrate with the passivation solution and passing an electrical current between the substrate as a cathode and an anode in the passivation solution such that a passivation layer is deposited onto the outermost layer, wherein the trivalent chromium ions are obtained by chemically reducing hexavalent chromium in presence of phosphoric acid and at least one reducing agent, with the proviso that during or after the chemical reducing the one or more than one organic acid residue anion is present for the first time in the passivation solution.

Abstract: A method for post-treatment of a chromium finish surface to improve corrosion resistance comprising a) providing a substrate having a chromium finish surface, and at least one intermediate layer between the chromium finish surface and the substrate, selected from the group consisting of nickel, nickel alloys, copper and copper alloys, wherein the chromium finish surface is a surface of a trivalent chromium plated layer, obtained by electroplating the substrate, having the at least one intermediate layer, in a plating bath, the plating bath comprising chromium (III) ions; b) contacting the chromium finish surface with an aqueous solution, comprising a permanganate, at least one compound which is selected from a phosphorus-oxygen compound, a hydroxide, a nitrate, a borate, boric acid, a silicate, or a mixture of two or more of these compounds; c) forming a transparent corrosion protection layer onto the chromium finish surface during step b.