Surface cleaning and activation for electrodeposition in ionic liquids

Abstract

A surface preparation solution comprises an ionic liquid solvent and a water and oxygen scavenging species. Methods for making the solution, and methods for using the solution to prepare and activate a substrate surface for bulk electrodeposition are also disclosed.

1 . A surface preparation solution for electrodeposition in ionic liquids comprising:
 an ionic liquid solvent; and   a water and oxygen scavenging species.   
     
     
         2 . The solution of  claim 1 , wherein the water and oxygen scavenging species comprises an acid halide including a halogen atom bonded to the carbon atom of a carbonyl group. 
     
     
         3 . The solution of  claim 2 , further comprising a metal halide salt, wherein the halide of the salt is a halide form of the halogen atom bonded to the carbon atom of the carbonyl group. 
     
     
         4 . The solution of  claim 2 , wherein the acid halide is an acid chloride. 
     
     
         5 . The solution of  claim 1 , wherein the water and oxygen scavenging species comprises a member of the phosgene family. 
     
     
         6 . The solution of  claim 5 , wherein the water and oxygen scavenging species exists in solution primarily as phosgene (carbonyl dichloride, COCl 2 ). 
     
     
         7 . The solution of  claim 1 , wherein the water and oxygen scavenging species comprises a thionyl halide having a halogen atom bonded to the sulfur atom of a thionyl group. 
     
     
         8 . The solution of  claim 7 , wherein the thionyl halide is thionyl chloride. 
     
     
         9 . The solution of  claim 1 , wherein the ionic liquid solvent comprises at least one of: 1-ethyl-3-methylimidazolium chloride, 1 -butyl-3-methylimidazolium chloride, 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) amide, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, trihexyl-tetraadecyl phosphonium bis(trifluoromethylsulfonyl) amide, and mixtures thereof. 
     
     
         10 . A method for making a surface preparation and activation solution for ionic liquid electrodeposition, the method comprising:
 providing an ionic liquid solvent compatible with the substrate surface and a species to be deposited from the ionic liquid; and   adding a water and oxygen scavenging species to the ionic liquid solvent.   
     
     
         11 . The method of  claim 10 , wherein the water and oxygen scavenging species is an acid halide including a halogen atom bonded to the carbon atom of a carbonyl group. 
     
     
         12 . The method of  claim 10 , wherein the water and oxygen scavenging species is selected from the phosgene family. 
     
     
         13 . The method of  claim 12 , wherein the water and oxygen scavenging species is added to the ionic liquid in at least one of a diphosgene form and a triphosgene form. 
     
     
         14 . The method of  claim 10 , wherein the water and oxygen scavenging species is thionyl chloride. 
     
     
         15 . A method for preparing and activating a substrate surface for electrodeposition, the method comprising:
 removing contamination and oxides from the substrate surface;   drying the surface in a substantially oxygen and water free environment; and   immersing the substrate surface into a surface preparation and activation solution, the solution comprising an ionic liquid solvent and a water and oxygen scavenging species.   
     
     
         16 . The method of  claim 15 , wherein the removing step comprises both mechanical and chemical removal of the contamination and oxides. 
     
     
         17 . The method of  claim 15 , wherein the drying step utilizes substantially pure dehumidified nitrogen. 
     
     
         18 . The method of  claim 15 , wherein the water and oxygen scavenging species comprises an acid chloride. 
     
     
         19 . The method of  claim 18 , wherein the water and oxygen scavenging species comprises at least one member of the phosgene family. 
     
     
         20 . The method of  claim 15 , further comprising:
 applying a reverse current during the immersing step to expedite scavenging of water and oxygen.   
     
     
         21 . A method for electrodepositing a bulk coating onto a substrate surface, the method comprising:
 preparing and activating the substrate surface according to the method of  claim 15 ;   submerging the substrate surface into a coating solution, the solution comprising an ionic liquid solvent and a metal halide salt dissociated in the ionic liquid solvent; and   applying an electrical current through the coating solution between an anode and the substrate surface operating as a cathode to deposit a bulk coating thereon.   
     
     
         22 . The method of  claim 21 , wherein the metal halide salt comprises aluminum. 
     
     
         23 . The method of  claim 21 , further comprising:
 depositing a thin film layer onto the prepared and activated substrate surface.   
     
     
         24 . The method of  claim 23 , wherein the thin film layer is a monolayer deposited via underpotential deposition.