Method of plating metal onto titanium

Abstract

A method of plating a metal onto a titanium surface comprising a surface cleaning step, an anodic etching step, a cathodic activation step and a plating step.

1 . A method of plating a metal onto a titanium surface, comprising the steps of:
 (a) positioning an electrode adjacent to a titanium surface, said electrode having an electrode surface conforming to the shape of said titanium surface and having a porous, abrasive pad positioned thereon, said pad on said electrode completely covering, and being in contact with, said titanium surface, wherein an interface is defined between said pad and said titanium surface and wherein said pad defines a gap between said titanium surface and said electrode surface;   (b) etching said titanium surface by applying a positive voltage to said titanium surface and a negative voltage to said electrode while maintaining said relative movement between said titanium surface and said pad and maintaining said wetting of said interface between said pad and said titanium surface with said etching solution;   (c) activating said titanium surface by applying a negative voltage to said titanium surface and a positive voltage to said electrode while maintaining said wetting of said interface between said pad and said titanium surface with said etching solution and maintaining said relative movement between said titanium surface and said pad; and   (d) plating a metal onto said titanium surface by applying a plating solution to said interface between said pad and said titanium surface while applying a negative voltage to said titanium surface and a positive voltage on said electrode, and while maintaining said relative movement between said titanium surface and said pad, said pad maintaining complete coverage of said titanium surface during said abrading step, said etching step, said activating step and said plating step.   
   
   
       2 . A method as defined in  claim 1 , wherein said etching solution and said plating solution flow through said electrode and through said pad. 
   
   
       3 . A method as defined in  claim 1 , further comprising a support block disposed above said electrode. 
   
   
       4 . A method as defined in  claim 3 , wherein said support block is comprised of a polymer material. 
   
   
       5 . A method as defined in  claim 3 , wherein said support block includes a plurality of fluid supply channels formed therein, wherein said fluid supply channels fluidly communicate with a source of said etching solution and a source of said plating solution. 
   
   
       6 . A method as defined in  claim 5 , further comprising a valve operable to selectively connect said fluid supply channels to said source of said etching solution and said source of said plating solution. 
   
   
       7 . A method as defined in  claim 1 , wherein said titanium surface is stationary. 
   
   
       8 . A method as defined in  claim 1 , wherein said titanium surface is planar. 
   
   
       9 . A method as defined in  claim 1 , wherein said titanium surface is a non-planar surface. 
   
   
       10 . A method as defined in  claim 1 , wherein said pad is made from a material selected from the group consisting of nylon, Dacron and cotton gauze. 
   
   
       11 . A method as defined in  claim 1 , wherein said etching solution is an acid solution. 
   
   
       12 . A method as defined in  claim 11 , wherein said etching solution contains about 10% NaCl, about 7% HCl, about 1% Ni salts and about 0.3% citric acid by weight. 
   
   
       13 . A method as defined in  claim 1 , wherein said plating solution is comprised of an acid nickel sulfate solution. 
   
   
       14 . A method as defined in  claim 1 , further comprising a step of:
 abrading said titanium surface by producing relative movement between said titanium surface and said pad while simultaneously wetting said interface between said pad and said titanium surface with an etching solution, said abrading step preceding said etching step.   
   
   
       15 . A method of plating a surface of a first metal with a second metal, comprising the steps of:
 (a) positioning an electrode adjacent to a surface of a first metal, said electrode having a porous, abrasive pad positioned thereon, said pad on said electrode completely covering, and being in contact with, said surface of said first metal, wherein an interface is defined between said pad and said surface of said first metal and wherein said pad defines a gap between said surface of said first metal and said electrode surface;   (b) etching said surface of said first metal by applying a positive voltage to said surface of said first metal and a negative voltage to said electrode while maintaining said relative movement between said surface of said first metal and said pad and maintaining said wetting of said interface between said pad and said surface of said first metal with said etching solution;   (c) activating said surface of said first metal by applying a negative voltage to said surface and a positive voltage to said electrode while maintaining said wetting of said interface between said pad and said surface of said first metal with said etching solution and maintaining said relative movement between said surface of said first metal and said pad; and   (d) plating a second metal onto said surface of said first metal by applying a plating solution to said interface between said pad and said surface of said first metal while applying a negative voltage to said surface of said first metal and a positive voltage on said electrode, and while maintaining said relative movement between said surface of said first metal and said pad, said pad maintaining complete coverage of said surface of said first metal during said abrading step, said etching step, said activating step and said plating step.   
   
   
       16 . A method as defined in  claim 15 , wherein said electrode has a surface conforming to the shape of said surface of said first metal. 
   
   
       17 . A method as defined in  claim 15 , wherein said etching solution and said plating solution flow through said electrode and through said pad. 
   
   
       18 . A method as defined in  claim 15 , further comprising a support block disposed above said electrode. 
   
   
       19 . A method as defined in  claim 18 , wherein said support block is comprised of a polymer material. 
   
   
       20 . A method as defined in  claim 18 , wherein said support block includes a plurality of fluid supply channels formed therein, wherein said fluid supply channels fluidly communicate with a source of said etching solution and a source of said plating solution. 
   
   
       21 . A method as defined in  claim 15 , further comprising a valve operable to selectively connect said fluid supply channels to said source of said etching solution and said source of said plating solution. 
   
   
       22 . A method as defined in  claim 15 , wherein said first metal is a quickly oxidizing metal. 
   
   
       23 . A method as defined in  claim 22 , wherein said first metal is titanium. 
   
   
       24 . A method as defined in  claim 22 , wherein said first metal is a titanium alloy. 
   
   
       25 . A method as defined in  claim 24 , wherein said second metal is nickel. 
   
   
       26 . A method as defined in  claim 15 , wherein said pad is made from a material selected from the group consisting of nylon, Dacron and cotton gauze. 
   
   
       27 . A method as defined in  claim 15 , wherein said etching solution is an acid solution. 
   
   
       28 . A method as defined in  claim 27 , wherein said etching solution contains about 10% NaCl, about 7% HCl, about 1% Ni salts and about 0.3% citric acid by weight. 
   
   
       29 . A method as defined in  claim 15 , wherein said plating solution is comprised of an acid nickel sulfate solution. 
   
   
       30 . A method as defined in  claim 15 , further comprising a step of:
 abrading said surface of said first metal by producing relative movement between said surface of said first metal and said pad while simultaneously wetting said interface between said pad and said surface of said first metal with an etching solution, said abrading step preceding said etching step.   
   
   
       31 . A system for plating a metal onto a titanium surface comprised of:
 an electrode dimensioned to be disposed adjacent to a titanium surface, said electrode having an electrode surface dimensioned to conform to the shape of said titanium surface;   a porous abrasive pad disposed on said electrode surface, said pad dimensioned to cover and contact said titanium surface, such that said pad defines a gap between said electrode and said titanium surface; and   selective means for selectively supplying an etching solution and a plating solution to said gap between said electrode and said titanium surface such that said titanium surface is covered by said etching solution or said plating solution when said titanium surface is plated and said pad and said titanium surface continuously move relative to each other when said titanium surface is abraded, etched, activated, and plated.   
   
   
       32 . A system as defined in  claim 31 , further comprising:
 a support block disposed above said electrode, said support block including a plurality of fluid supply channels formed therein, said fluid supply chains fluidly communicating with a source of said etching solution and a source of said plating solutions.   
   
   
       33 . A system as defined in  claim 32 , wherein said selective means is a valve operable to selectively connect said fluid supply channels to said source of said etching solution and said source of said plating solution. 
   
   
       34 . A system as defined in  claim 31 , wherein said pad is made from a material selected from the group consisting of nylon, Dacron and cotton gauze.