Graphite metal coating

Abstract

A method for applying a metal coating to graphite structural members, in which a galvanic metal layer is deposited after said graphite structural members have been anodically etched in an alkaline etchant. The metal coating can serve as a basis for solder connections and can be employed for creating electrical contacts or for mechanically fixing the graphite structural member or it can fulfil other demands on the surface (e.g. abrasion resistance).

I claim:  
     
         1 . A method of applying a metal coating to graphite comprising: 
 anodic etching said graphite in an alkaline etchant, and then electroplating said graphite.    
     
     
         2 . The method as set forth in  claim 1 , comprising the following step between said anodic etching and said electroplating: 
 Pd seeding said graphite.    
     
     
         3 . The method as set forth in  claim 2 , comprising the following step between said Pd seeding and said electroplating: 
 electroless plating to reinforce said Pd coating.    
     
     
         4 . The method as set forth in  claim 3 , wherein at least Ni or Cu is deposited in said electroless plating step.  
     
     
         5 . The method as set forth in  claim 1 , comprising the following step between said anodic etching and a subsequent step: 
 directly transferring said graphite, obtained with said anodic etching step, into water or a weak aqueous solution.    
     
     
         6 . The method as set forth in  claim 5 , wherein between said anodic etching and said electroplating no ultrasound treatment is implemented.  
     
     
         7 . The method as set forth in  claim 1 , wherein said electroplating involves at least one of the following group: Ag, Cu, Ni and Sn.  
     
     
         8 . The method as set forth in  claim 1 , wherein said electroplating utilizes a current density in the range 0.1 to 10 A/dm 2 .  
     
     
         9 . The method as set forth in  claim 1 , wherein the current duration in said electroplating is in the range of 5 to 90 minutes.  
     
     
         10 . The method as set forth in  claim 1 , wherein said anodic etching is done in a solution of NaOH and/or KOH having a concentration in the range 10 to 70% by weight.  
     
     
         11 . The method as set forth in  claim 10 , wherein said anodic etching is done at a temperature in the range 20° C. to 70° C.  
     
     
         12 . The method as set forth in  claim 1 , wherein said graphite comprises graphite particles bound by plastics.  
     
     
         13 . A method of fabricating a solder connection to a graphite component wherein, by a method as set forth in  claim 1 , a metal coating is deposited on said graphite component, after which a solder pad is applied to said metal coating as thus produced.  
     
     
         14 . A method as set forth in  claim 1 , wherein said anodic etching is performed with an applied electrical potential in the range of 4V to 20V.  
     
     
         15 . A method as set forth in  claim 14 , wherein said anodic etching has a duration in the range of 5 to 90 minutes, with the actual duration being inversely proportional to the applied electrical potential.