US2004011431A1PendingUtilityA1

Passivation method

35
Priority: Nov 7, 2000Filed: Nov 7, 2001Published: Jan 22, 2004
Est. expiryNov 7, 2020(expired)· nominal 20-yr term from priority
Inventors:Ernst-Walter Hillebrand
C23C 22/46C23C 2222/10C23C 22/53
35
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Claims

Abstract

The invention refers to a method for the passivation of zinc, cadmium or their alloys, in particular of zinc-nickel alloys by means of a chrome(VI) free solution containing a weak complexing agent, preferably di- or tri-carbonic acids, preferably chrome(III)-oxalate complex and Co 2+ , whereby the concentration of Co 2+ is greater than 30 g/l.

Claims

exact text as granted — not AI-modified
1 . Method for the passivation of zinc, cadmium or their alloys, in particular of zinc-nickel alloys by means of a chrome(VI) free solution containing a weak complexing agent preferably di- or tri-carbonic acids, preferably chrome(III)-oxalate complex and Co 2+ , characterized in that the Co 2+  concentration is greater than 30 g/l.  
     
     
         2 . Method according to  claim 1 , characterized in that the Co 2+  concentration is 70 to 110 g/l.  
     
     
         3 . Method according to  claim 1 , characterized in that the Co 2+  concentration is about 90 g/l.  
     
     
         4 . Method according to one of the preceding claims, characterized in that the passivation is carried out at 20° C. to 55° C.  
     
     
         5 . Method according to one of the preceding claims, characterized in that the passivation is carried out at pH 0,5 to 5,5.  
     
     
         6 . Method according to one of the preceding claims, characterized in that the passivation is carried out at pH 4.  
     
     
         7 . Method according to one of the preceding claims, characterized in that the ratio of chrome to cobalt is 1,7: 2,0.  
     
     
         8 . Method according to one of the preceding claims, characterized in that the solution is sulfate free.  
     
     
         9 . Method according to one of the preceding claims, characterized in that the passivated layer is treated by an additional coating.  
     
     
         10 . Method according to one of the preceding claims characterized by a coating with Aquares™.  
     
     
         11 . Method according to one of the preceding claims, characterized by a double coating with Aquares™.  
     
     
         12 . Method according to one of the preceding claims, characterized in that the passivated layer is treated with a dry lubricant.  
     
     
         13 . Method according to one of the preceding claims, characterized in that the passivated layer is coated with an organic Topcoat.  
     
     
         14 . Method according to one of the preceding claims, characterized in that the passivated layer is treated with a PTFE-containing coat.  
     
     
         15 . Method according to the preceding claim, characterized in that the passivated layer is coated with Molykote® D 7100.

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