Activation of aluminum for electrodeposition or electroless deposition

Abstract

Method for treating an aluminum alloy surface for electrodeposition or electroless deposition of a metal or alloy on the surface, the surface is oxidized (e.g. anodized) to form aluminum oxide, and then the oxidized surface is chemically etched to render the surface amenable for electrodeposition or electroless deposition of the metal or alloy thereon. A metallic coating can be electrodeposited or electroless deposited on the treated surface.

1 . Method of treating a surface comprising aluminum for electrodeposition or electroless deposition of a metal or alloy on the surface, comprising the steps of: providing a surface comprising an alloy of aluminum and an alloying element, oxidizing the surface on the alloy to form aluminum oxide thereon, and chemically etching the oxidized surface to render the surface amenable for electrodeposition or electroless deposition.  
   
   
       2 . The method of  claim 1  wherein the surface is provided as an alloy of aluminum and an element selected from the group consisting of copper, silicon, magnesium, zinc, silver, gold, tungsten, chromium, lead, nickel, titanium or combination thereof.  
   
   
       3 . The method of  claim 1  wherein the surface is provided on a film or layer of the alloy.  
   
   
       4 . The method of  claim 3  wherein the film or layer is deposited on a substrate by physical vapor deposition.  
   
   
       5 . The method of  claim 3  wherein the alloy includes about 0.5 weight % copper and balance aluminum.  
   
   
       6 . The method of  claim 1  wherein the surface is oxidized by anodizing, polishing, alkaline etching, acid pickling, electropolishing, or heating in an oxygen bearing atmosphere.  
   
   
       7 . The method of  claim 1  wherein the anodized surface is acid etched for a time to render the surface amenable for deposition of the metal or alloy thereon.  
   
   
       8 . The method of  claim 7  wherein the surface is acid etched by contact with a mixture of phosphoric acid and chromic acid.  
   
   
       9 . The method of  claim 1  wherein the metal or alloy comprises one or more noble metals.  
   
   
       10 . The method of  claim 1  wherein the metal or alloy comprises a non-noble metal including Cu, Ni, Cr, Cd, Pb, Sn, or a combination thereof.  
   
   
       11 . The method of  claim 9  wherein the metal or alloy further comprises another metal including Ni, Co, Fe, Cr, Mo, W, or a combination thereof.  
   
   
       12 . The method of  claim 1  including the additional step of electrodepositing the metal or alloy on the surface.  
   
   
       13 . The method of  claim 1  wherein the metal or alloy is electrodeposited on the surface as a metallic coating.  
   
   
       14 . The method of  claim 13  wherein the coating comprises a particle-type noble metal coating with both controlled particle density and controlled narrow particle size distribution.  
   
   
       15 . The method of  claim 1  including the additional step of electroless depositing the metal or alloy on the surface.  
   
   
       16 . The method of  claim 15  wherein the metal or alloy comprises one or more noble metals.  
   
   
       17 . The method of  claim 15  wherein the metal or alloy comprises a non-noble metal including Cu, Ni, Cr, Cd, Pb, Sn, or a combination thereof.  
   
   
       18 . The method of  claim 16  wherein the metal or alloy further comprises another metal including Ni, Co, Fe, Cr, Mo, W, or a combination thereof.  
   
   
       19 . The method of  claim 15  wherein the metal or alloy is electroless deposited as a metallic coating on the surface.  
   
   
       20 . The method of  claim 15  wherein the electroless depositing occurs in the presence of an external agent or by galvanic displacement where a reducing agent resides in and/or underneath the aluminum oxide.