Ruthenium Alloy Layer and Its Layer Combinations

Abstract

Aqueous electrolyte for deposition of a ruthenium alloy layer on metal surfaces, in particular base metal surfaces, its use and a corresponding electrolytic process, and a correspondingly produced layer sequence.

1 - 15 . (canceled) 
     
     
         16 . An aqueous electrolyte for deposition of ruthenium alloys on metal surfaces, in particular base metal surfaces, comprising:
 a) ruthenium as a bicyclic, anionic ruthenium nitrido complex compound of the formula [Ru 2 N(H 2 O) 2 X 8 ] 3− , wherein X is one or more singly or multiply negatively charged counterions, at a concentration of 0.5-20 g/l based on ruthenium as metal;   b) one or more alloy metals dissolved in ionic form and selected from the group consisting of: Cu, W, Fe, Co, Ni, In, Zn, Sn, Pd, and Pt, each at a concentration of 0.1-10 g/l based on the metal;   c) one or more anions of a di-, tri-, or tetracarboxylic acid at a concentration of 0.05-2 mol per liter;   d) one or more anionic surfactants at a concentration of 0.1-500 mg/1;   wherein the electrolyte has a pH value of 5.0 to 10.0.   
     
     
         17 . The electrolyte according to  claim 16 , wherein the carboxylic acid is selected from the group consisting of oxalic acid, citric acid, tartaric acid, succinic acid, maleic acid, glutaric acid, adipic acid, malonic acid, and malic acid. 
     
     
         18 . The electrolyte according to  claim 16 , wherein the surfactant is selected from the group consisting of fatty alcohol sulfates, alkyl sulfates, alkyl sulfonates, aryl sulfonates, alkylaryl sulfonates, heteroaryl sulfates salts, and alkoxylated derivatives thereof. 
     
     
         19 . The electrolyte according to  claim 16 , wherein the pH value of the electrolyte is in a range of 7-8. 
     
     
         20 . The electrolyte according  claim 16 , wherein the electrolyte has a buffer system selected from the group consisting of borate, phosphate, and carbonate buffers. 
     
     
         21 . The electrolyte according  claim 16 , wherein the alloy metal is selected from the group of Ni, Pd, Pt, Sn, Zn, and Co. 
     
     
         22 . The electrolyte according  claim 16 , wherein it does not contain sulfur-containing compounds in which the sulfur is present in an oxidation state of ≤+4. 
     
     
         23 . A method for producing an article having a metal surface and an alloy metal layer thereon, which comprises electrolytically depositing the alloy metal layer on the metal surface using the aqueous electrolyte according to claim  1 . 
     
     
         24 . The method according to  claim 23 , wherein the alloy metal layer has a thickness of 0.05-5 μm 
     
     
         25 . The method according to  claim 23 , wherein the alloy metal layer serves as a sublayer for a further electrolytically deposited metal layer of noble metals or alloys thereof, wherein the latter has a thickness of 0.05-5 μm. 
     
     
         26 . The method according to  claim 23 , wherein the metal layer(s) produced has/have an abrasion resistance of less than 0.25 μm/1000 strokes per the Bosch-Weinmann test. 
     
     
         27 . A process for electrolytically depositing an alloy metal layer on metal surfaces, in particular base metal surfaces, in which:
 a) the metal surface is brought into contact as a cathode with an aqueous electrolyte according to  claim 16 ;   b) an anode is brought into contact with the electrolyte; and   c) a sufficient current flow is established between the cathode and the anode.   
     
     
         28 . The process according to  claim 27 , wherein the current density in the electrolyte is 0.1-50.0 A/dm 2 . 
     
     
         29 . The process according to  claim 27 , wherein the temperature during the electrolysis is between 20° C. and 80° C. 
     
     
         30 . A metal layer sequence comprising a substrate provided with a metal surface, in particular a base metal surface, an alloy metal layer which is electrolytically deposited thereon and produced by a process according to  claim 27 .