Abstract: The present invention relates to an aqueous passivation solution having a pH in the range from 5.4 to 7.2, the solution including trivalent chromium ions, and formate anions and/or oxalate anions as complexing agents for said trivalent chromium ions, in which the trivalent chromium ions with respect to all formate anions together with all oxalate anions form a molar ratio in the range from 1:15 to 1:400.

Abstract: The present invention relates to an aqueous passivation solution having a pH in the range from 5.4 to 7.2, the solution including trivalent chromium ions, and formate anions and/or oxalate anions as complexing agents for said trivalent chromium ions, in which the trivalent chromium ions with respect to all formate anions together with all oxalate anions form a molar ratio in the range from 1:15 to 1:400.

Abstract: 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 the 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 the 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 the 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.

Abstract: 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.