Non-reactive coatings for inertization

Abstract

A method for the selective or complete rendering inert of substrates, workpieces, and components of the apparatus in the chemical deposition of metals by depositing nonreactive coatings thereon. A coating which is nonreactive with respect to the subsequent plating is electrolytically deposited on the sites of the substrate which are not to be plated from a solution containing an activator and an electrolyte. The inert, nonreactive coating is removable by means of dilute acids or alkaline media, without manual effort, after the subsequent chemical plating of the substrates, workpieces, or unit parts.

1 . A method for depositing a nonreactive coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 activating the surface for electrolytic deposition of the nonreactive coating; and    electrolytically depositing the nonreactive coating onto the surface.    
     
     
         2 . The method of  claim 1  wherein the nonreactive coating is inert to plating of a metal selected from the group consisting of copper, nickel, zinc, tin, lead, bismuth, palladium, silver, gold, and platinum, and combinations thereof.  
     
     
         3 . The method  claim 1  wherein said activating comprises contacting the surface with a fluoride-containing solution.  
     
     
         4 . The method of  claim 1  wherein the surface is a material selected from the group consisting of metals, metal compounds, alloys, plastics, and combinations thereof.  
     
     
         5 . The method of  claim 1  wherein said electrolytically depositing the nonreactive coating comprises depositing from a chromium-containing electrolyte.  
     
     
         6 . The method of  claim 1  wherein said electrolytically depositing the nonreactive coating comprises application of a cathode current.  
     
     
         7 . The method of  claim 1  wherein the electrolytic deposition of the nonreactive coating comprises application of a cathode current having a current density below about 10 A/dm 2 .  
     
     
         8 . The method of  claim 1  wherein the electrolytic deposition of the nonreactive coating comprises application of a cathode current having a current density below about 5 A/dm 2 .  
     
     
         9 . The method of  claim 1  wherein the electrolytic deposition of the nonreactive coating is performed at a temperature below about 40° C.  
     
     
         10 . The method of  claim 1  comprising electroless metal deposition of metal onto the surface after electrolytically depositing the nonreactive coating, wherein the nonreactive coating is not plated during the electroless metal deposition.  
     
     
         11 . The method of  claim 10  comprising removing the nonreactive coating after the electroless metal deposition.  
     
     
         12 . The method of  claim 10  comprising removing the nonreactive coating after the electroless metal deposition by contacting the nonreactive coating with an acid.  
     
     
         13 . The method of  claim 10  comprising removing the nonreactive coating after the electroless metal deposition by contacting the nonreactive coating with an alkaline solution and applying anodic polarization.  
     
     
         14 . The method of  claim 1  wherein the surface is of a component of an electroless metal deposition apparatus.  
     
     
         15 . The method of  claim 1  wherein the activating the surface and the electrolytically depositing the nonreactive coating are performed in a single operation employing an electrolyte containing an activator.  
     
     
         16 . The method of  claim 1  wherein the activating the surface and the electrolytically depositing the nonreactive coating are performed in a single operation employing an electrolyte containing a fluoride activator and a source of chromium ions for the nonreactive coating; the process further comprising: 
 electrolessly depositing metal onto the surface after electrolytically depositing the nonreactive coating, wherein the nonreactive coating is not plated during the electroless metal deposition; and    removing the nonreactive coating.    
     
     
         17 . A method for depositing a nonreactive coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 immersing the surface in an electrolyte comprising an activator for electrolytic deposition of the nonreactive coating and precursor ions for the nonreactive coating; and    applying an external source of electrons to electrolytically deposit the nonreactive coating onto the surface.    
     
     
         18 . The method of  claim 17  comprising: 
 electrolessly depositing metal onto the surface after electrolytically depositing the nonreactive coating, wherein the nonreactive coating is not plated during the electroless metal deposition.    
     
     
         19 . A method for depositing a chromium-based nonreactive coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 immersing the surface in an electrolyte comprising a fluoride activator and chromium ions for the nonreactive coating; and    applying an external source of electrons to electrolytically deposit the chromium-based nonreactive coating onto the surface.    
     
     
         20 . The method of  claim 19  wherein the electrolyte comprises between about 0.02 and about 0.3 g/L fluoride and between about 200 and about 300 g/L chromium oxide.  
     
     
         21 . The method of  claim 19  comprising: 
 electrolessly depositing metal onto the surface after electrolytically depositing the chromium-based nonreactive coating, wherein the chromium-based nonreactive coating is not plated during the electroless metal deposition.    
     
     
         22 . A method for depositing a chromium-based nonreactive coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition to which the surface is exposed, the method comprising: 
 immersing the surface in an electrolyte comprising between about 0.02 and about 0.3 g/L fluoride, between about 200 and about 300 g/L chromium oxide, between about 1 and about 3 g/L sulfuric acid, and between about 0.2 and 3 g/L methanesulfonic acid or a derivative thereof; and    applying an external source of electrons to electrolytically deposit the chromium-based nonreactive coating onto the surface.    
     
     
         23 . A method for depositing a nonreactive coating which is inert to metal plating onto a surface of a component of an electroless metal deposition apparatus, the method comprising: 
 immersing the surface in an electrolyte comprising an activator for electrolytic deposition of the nonreactive coating and precursor ions for the nonreactive coating; and    applying an external source of electrons to electrolytically deposit the nonreactive coating onto the surface to thereby render the surface resistant to electroless metal plating.    
     
     
         24 . A method for depositing a chromium-based nonreactive coating which is inert to metal plating onto a surface of a component of an electroless metal deposition apparatus, the method comprising: 
 immersing the surface in an electrolyte comprising a fluoride activator and chromium ions; and    applying an external source of electrons to electrolytically deposit the chromium-based nonreactive coating onto the surface to thereby render the surface resistant to electroless metal plating.    
     
     
         25 . A method for depositing a chromium-based nonreactive coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 immersing the surface in an electrolyte comprising a fluoride activator and chromium ions;    applying an external source of electrons to electrolytically deposit the chromium-based nonreactive coating onto the surface; electrolessly depositing a metal selected from the group consisting of copper, nickel, zinc, tin, lead, bismuth, palladium, silver, gold, and platinum, and combinations thereof onto the surface after electrolytically depositing the chromium-based nonreactive coating, wherein the chromium-based nonreactive coating is not plated during the electroless metal deposition; and    removing the chromium-based nonreactive coating.    
     
     
         26 . The method of  claim 25  wherein the electrolyte comprises between about 0.02 and about 0.3 g/L fluoride and between about 200 and about 300 g/L chromium oxide.  
     
     
         27 . The method of  claim 25  wherein the electrolyte comprises between about 0.02 and about 0.3 g/L fluoride, between about 200 and about 300 g/L chromium oxide, between about 1 and about 3 g/L sulfuric acid, and between about 0.2 and 3 g/L methanesulfonic acid or a derivative thereof.  
     
     
         28 . An electrolyte for depositing a nonreactive coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the electrolyte comprising: 
 a fluoride activator; and    a source of chromium ions for the nonreactive coating.    
     
     
         29 . The electrolyte of  claim 28  comprising between about 0.02 and about 0.3 g/L fluoride, and between about 200 and about 300 g/L chromium oxide as the source of chromium ions.  
     
     
         30 . The electrolyte of  claim 28  comprising between about 0.02 and about 0.3 g/L fluoride, between about 200 and about 300 g/L chromium oxide as the source of chromium ions, between about 1 and about 3 g/L sulfuric acid, and between about 0.2 and 3 g/L methanesulfonic acid or a derivative thereof.  
     
     
         31 . A method for depositing a chromium coating which is inert to metal plating onto a surface which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 immersing the surface which is not to be plated in the subsequent metal deposition process in an electrolyte comprising a source of chromium ions; and    applying a cathodic current to the surface with a current density below about 10 A/dm 2  to electrolytically deposit the chromium coating which is inert to metal plating thereon.    
     
     
         32 . The method of  claim 31  wherein the electrolytic deposition of the nonreactive coating is performed at a temperature below about 40° C.  
     
     
         33 . The method of  claim 31  wherein the source of chromium ions is a chromium oxide.  
     
     
         34 . The method of  claim 31  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating onto a substrate.  
     
     
         35 . The method of  claim 31  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating of a metal selected from the group consisting of copper, nickel, zinc, tin, lead, bismuth, palladium, silver, gold, and platinum, and combinations thereof onto a substrate.  
     
     
         36 . A method for depositing a nonreactive coating which is inert to metal plating onto a surface of a component of a metal deposition apparatus which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 activating the surface of the component of the metal deposition apparatus for electrolytic deposition of the nonreactive coating onto the surface of the component of the metal deposition apparatus; and    electrolytically depositing the nonreactive coating onto the surface of the component of the metal deposition apparatus.    
     
     
         37 . The method of  claim 36  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating onto a substrate.  
     
     
         38 . The method of  claim 36  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating of nickel onto a substrate.  
     
     
         39 . The method of  claim 36  wherein said activating comprises contacting the surface with a fluoride-containing solution.  
     
     
         40 . The method of  claim 39  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating onto a substrate.  
     
     
         41 . The method of  claim 39  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating of nickel onto a substrate.  
     
     
         42 . The method of  claim 36  wherein the electrolytically depositing the nonreactive coating comprises: 
 immersing the surface of the component of the metal deposition apparatus which is not to be plated in the subsequent metal deposition process into an electrolyte comprising a source of chromium ions; and    applying an external source of electrons to electrolytically deposit a chromium coating onto the surface of the component of the metal deposition apparatus which is not to be plated in the subsequent metal deposition process.    
     
     
         43 . The method of  claim 42  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating onto a substrate.  
     
     
         44 . The method of  claim 42  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating of nickel onto a substrate.  
     
     
         45 . The method of  claim 39  wherein the electrolytically depositing the nonreactive coating comprises: 
 immersing the surface of the component of the metal deposition apparatus which is not to be plated in the subsequent metal deposition process an electrolyte comprising a source of chromium ions; and    applying an external source of electrons to electrolytically deposit a chromium coating onto the surface of the component of the metal deposition apparatus which is not to be plated in the subsequent metal deposition process.    
     
     
         46 . The method of  claim 45  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating onto a substrate.  
     
     
         47 . The method of  claim 45  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating of nickel onto a substrate.  
     
     
         48 . The method of  claim 36  wherein the component of a metal deposition apparatus which is not to be plated in a subsequent metal deposition process is a stainless steel electroless metal deposition tank.  
     
     
         49 . The method of  claim 38  wherein the component of a metal deposition apparatus which is not to be plated in a subsequent metal deposition process is a stainless steel electroless metal deposition tank.  
     
     
         50 . A method for depositing a nonreactive coating which is inert to metal plating onto a surface of a component of a metal deposition apparatus which is not to be plated in a subsequent metal deposition process to which the surface is exposed, the method comprising: 
 immersing the surface of the component of the metal deposition apparatus which is not to be plated in the subsequent metal deposition process an electrolyte comprising a source of chromium ions; and    applying a cathodic current to the surface with a current density below about 10 A/dm 2  to electrolytically deposit the chromium coating thereon.    
     
     
         51 . The method of  claim 50  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating onto a substrate.  
     
     
         52 . The method of  claim 50  further comprising exposing the surface which is not to be plated in the subsequent metal deposition process to the subsequent metal deposition process, wherein the subsequent metal deposition process comprises electroless plating of nickel onto a substrate.