Method for depositing nickel- and chromium (VI) -free metal matte layers

Abstract

A method for depositing metal matte layers free of nickel and chromium(VI).

1 . A method for depositing a matte layer free of nickel and chromium(VI) onto a substrate, the method comprising: 
 (a) coating the substrate with a first matte metal layer that is free of nickel;    (b) metallizing the first matte metal layer with a second metal layer that is free of nickel and chromium(VI), which assumes the matte effect of the first matte metal layer;    wherein the first matte metal layer comprises at least one metal selected from the group consisting of copper, silver, tin, zinc, or an alloy that does not contain nickel; and    wherein the second metal layer comprises at least one metal selected from the group consisting of copper, tin, zinc, chromium(III), silver, gold, ruthenium, platinum, palladium, or an alloy of these metals.    
     
     
         2 . The method of  claim 1 , wherein the first matte metal layer is deposited chemically.  
     
     
         3 . The method of  claim 1 , wherein the first matte metal layer is electrolytically deposited.  
     
     
         4 . The method of  claim 1 , wherein the second metal layer is chemically deposited.  
     
     
         5 . The method of  claim 1 , wherein the second metal layer is deposited electrolytically.  
     
     
         6 . The method of  claim 1  further comprising coating the second metal layer with a third layer.  
     
     
         7 . The method of  claim 6 , wherein the third layer comprises chromium.  
     
     
         8 . The method of  claim 6 , wherein the third layer comprises chromium alloyed with at least one element selected from the group consisting of vanadium, molybdenum, carbon, phosphorous, tungsten, and mixtures thereof.  
     
     
         9 . The method of  claim 1 , the method further comprising coating the second metal layer with a third layer and at least one hard layer applied by CVD or PVD.  
     
     
         10 . The method of  claim 9 , wherein the hard layer comprises a material selected from the group consisting of chromium carbide, titanium nitride, titanium carbide, zirconium nitride, zirconium carbide, silicon dioxide, diamond-like carbon, and combinations thereof.  
     
     
         11 . The method of  claim 9  wherein the third layer comprises chromium.  
     
     
         12 . The method of  claim 9 , wherein the third layer comprises chromium alloyed with at least one element selected from the group consisting of vanadium, molybdenum, carbon, phosphorous, tungsten, and mixtures thereof.  
     
     
         13 . A method for imparting a decorative matte finish to a surface of an article comprising: 
 coating the surface with a first matte layer of metal which a) contains at least one metallic material selected from the group consisting of copper, tin, silver, zinc, and metal alloys, and b) is substantially nickel-free; and    depositing a second matte layer over the first matte layer, which second matte layer is a layer of metal which a) contains at least one metallic material selected from the group consisting of copper, tin, zinc, chromium, silver, gold, ruthenium, platinum, palladium, and metal alloys of the foregoing, b) is substantially free of nickel, c) is deposited from a composition which is substantially free of chromium (VI), and d) has a matte appearance.    
     
     
         14 . The method of  claim 13  further comprising depositing a third layer over the second metal layer, wherein the third layer comprises chromium, wherein the depositing the third layer is by a process employing a chromium-containing composition which is substantially free of chromium (VI).  
     
     
         15 . The method of  claim 14 , wherein the third layer comprises chromium alloyed with at least one element selected from the group consisting of vanadium, molybdenum, carbon, phosphorous, tungsten, and mixtures thereof.  
     
     
         16 . The method of  claim 13  further comprising depositing a third layer over the second metal layer and a hard layer over the second metal layer by CVD or PVD.  
     
     
         17 . The method of  claim 16 , wherein the hard layer comprises a material selected from the group consisting of chromium carbide, titanium nitride, titanium carbide, zirconium nitride, zirconium carbide, silicon dioxide, diamond-like carbon, and combinations thereof.  
     
     
         18 . The method of  claim 16  wherein the third layer comprises chromium.  
     
     
         19 . The method of  claim 18 , wherein the third layer comprises chromium alloyed with at least one element selected from the group consisting of vanadium, molybdenum, carbon, phosphorous, tungsten, and mixtures thereof.  
     
     
         20 . The method of  claim 13  wherein the coating the surface with the first matte layer of metal comprises immersing the surface in an electrolyte comprising Cu ions and applying an external source of electrical current to the electrolyte to electrolytically deposit a Cu-based layer as the first matte layer.  
     
     
         21 . The method of  claim 20  wherein the electrolyte comprises, by approximate composition: 
 18-25 g/L Cu 2+     180-210 g/L H 2 SO 4      30-80 mg/L Cl − .    
     
     
         22 . The method of  claim 21  wherein the electrical current has a current density between about 1 A/dm 2  and 5 A/dm 2  and the electrolyte has a temperature in a range between about 18° C. and 35° C.  
     
     
         23 . The method of  claim 13  wherein the second matte layer comprises tin and the depositing the second matte layer comprises immersing the surface in an electrolyte comprising Sn ions and applying an external source of electrical current to the electrolyte to electrolytically deposit a Sn-based layer as the second matte layer.  
     
     
         24 . The method of  claim 23  wherein the second matte layer is deposited using an electrolyte comprising, by approximate composition: 
 g/L Sn 2+     10 g/L Cu 2+     240 g/L methanesulfonic acid    32.2 g/L aromatic, nonionic wetting agent    2 g/L antioxidation agent    25 g/L stabilizer/complexing agent.    
     
     
         25 . The method of  claim 23  wherein the second matte layer is deposited using an electrolyte comprising, by approximate composition: 
 18 g/L Sn 2+     2 g/L Cu 2+     258 g/L methanesulfonic acid    9 g/L aromatic, nonionic wetting agent.    
     
     
         26 . The method of  claim 23  wherein the second matte layer is deposited using an electrolyte comprising, by approximate composition: 
 17.0-25.0 g/L Sn 2+     10.0-15.0 g/L Cu 2+     1.3-1.9 g/L Zn 2+     45.0-60.0 g/L KCN    0.5-2 mL/L wetting agent    0.1-1 mL/L gloss additive.    
     
     
         27 . The method of  claim 26  wherein the electrolyte has a pH value of between about 12.4 and about 12.9.  
     
     
         28 . The method of  claim 26  wherein the second matte layer is deposited at a temperature range of between about 50° C. and 60° C. and with a current density of between about 2 A/dm 2  and about 4 A/dm 2 .  
     
     
         29 . The method of  claim 13 , wherein the second matte layer is deposited using an electrolyte comprising, by approximate composition: 
 8.0-12.0 g/L Sn 2+     5.0-10.0 g/L Cu 2+     1.0-3.0 g/L Zn 2      23.0-30.0 g/L KCN    
     
     
         30 . The method of  claim 29 , wherein the electrolyte has a pH value of between about 13.2 and about 13.6.  
     
     
         31 . The method of  claim 29 , wherein the second matte layer is deposited at a temperature range of between about 39° C. and 45° C. and with a current density of between about 0.3 A/dm 2  and 0.7 A/dm 2 .  
     
     
         32 . The method of  claim 13 , wherein the first matte metal layer comprises copper.  
     
     
         33 . The method of  claim 13 , wherein the second matte layer comprises tin and copper.  
     
     
         34 . The method of  claim 13 , wherein the second matte layer comprises tin, copper, and zinc.  
     
     
         35 . The method of  claim 32 , wherein the first matte metal layer is between about 5 μm and about 30 μm thick.  
     
     
         36 . The method of  claim 35 , wherein the second matte layer is between about 5 μm and about 30 μm thick.  
     
     
         37 . A method for imparting a decorative matte finish to a surface of an article comprising: 
 immersing the surface in a first electrolyte comprising Cu ions and applying an external source of electrical current to the first electrolyte to electrolytically deposit a Cu-based layer as a first matte layer, wherein the first electrolyte is substantially nickel-free; and    depositing a second matte layer over the first matte layer by immersing the surface in a second electrolyte comprising Sn ions and applying an external source of electrical current to the second electrolyte to electrolytically deposit a Sn-based layer as the second matte layer, wherein the second electrolyte is substantially free of nickel and is substantially free of chromium (VI).