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.

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.

An aqueous composition for the electrolytic deposition of a chromium coating on the surface of a substrate is disclosed, in which it has a pH of between 0 and 1 and which contains a trivalent chromium salt, glycine, an alkali metal salt, an aluminium salt and, optionally, an ammonium salt. The chromium plating process according to the invention comprises the immersion of the substrate to be treated in this composition and the application of a current between this substrate and an anode. This process makes it possible to form a high-quality chromium coating on the entire surface of the substrate.

An aqueous composition for the electrolytic deposition of a chromium coating on the surface of a substrate is disclosed, in which it has a pH of between 0 and 1 and which contains a trivalent chromium salt, glycine, an alkali metal salt, an aluminium salt and, optionally, an ammonium salt. The chromium plating process according to the invention comprises the immersion of the substrate to be treated in this composition and the application of a current between this substrate and an anode. This process makes it possible to form a high-quality chromium coating on the entire surface of the substrate.

The present invention relates to a method for electrolytically passivating a surface of silver, silver alloy, gold, or gold alloy, the method comprising the steps of (i) providing a substrate comprising said surface, (ii) providing an aqueous passivation solution comprising trivalent chromium ions, and one or more than one species of carboxylic acid residue anions, (iii) contacting the substrate with said passivation solution and passing an electrical current between the substrate as a cathode and an anode such that a passivation layer is electrolytically deposited onto said surface, wherein the trivalent chromium ions with respect to all species of carboxylic acid residue anions form a molar ratio in the range from 1:10 to 1:400.

The present invention relates to a method for electrolytically passivating a surface of silver, silver alloy, gold, or gold alloy, the method comprising the steps of (i) providing a substrate comprising said surface, (ii) providing an aqueous passivation solution comprising trivalent chromium ions, and one or more than one species of carboxylic acid residue anions, (iii) contacting the substrate with said passivation solution and passing an electrical current between the substrate as a cathode and an anode such that a passivation layer is electrolytically deposited onto said surface, wherein the trivalent chromium ions with respect to all species of carboxylic acid residue anions form a molar ratio in the range from 1:10 to 1:400.

A method for producing a black plated resin part includes the steps of electroplating a resin substrate provided with an underlying plating layer in a trivalent chromium plating bath containing thiocyanic acid, to thereby form, on the underlying plating layer, a black chromium plating layer composed of trivalent chromium and having a thickness of 0.15 μm or more; and immersing the resin substrate provided with the black chromium plating layer in warm water at 30° C. or higher for a predetermined time. In the method, the amount of thiocyanic acid contained in the trivalent chromium plating bath, the temperature of the warm water, and the time of immersion of the resin substrate in the warm water are adjusted so that the black chromium plating layer exhibits a b* value of −1.7 or less based on the L*a*b* color system.

A method (400) for applying a coating to a substrate (124) includes spraying (414) an aluminum-based coating layer (120) on the substrate. The coating layer is then infiltrated (420) with an aqueous solution (610). The solution comprises: a source of chromium; and potassium hexafluorozirconate.

The present disclosure describes electrodeposited nanolaminate materials having layers comprised of nickel and/or chromium with high hardness. The uniform appearance, chemical resistance, and high hardness of the nanolaminate NiCr materials described herein render them useful for a variety of purposes including wear (abrasion) resistant barrier coatings for use both in decorative as well as demanding physical, structural and chemical environments.

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.