Systems and methods for treating a metal substrate

Abstract

Disclosed is a system for treating a metal substrate comprising a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L and a sealing composition comprising an ammonium-containing compound. Also disclosed is a method for treating a metal substrate that includes contacting at least a portion of a surface of the substrate with the conversion composition and then contacting at least a portion of the surface of the substrate with the sealing composition. Also disclosed is a substrate obtainable by treatment with the system and/or obtainable by the method of treatment.

1 . A system for treating a substrate comprising:
 a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L based on total weight of the conversion composition; and   a sealing composition comprising an ammonium-containing compound.   
     
     
         2 . (canceled) 
     
     
         3 . The system of  claim 1 , wherein the conversion composition further comprises a coinhibitor. 
     
     
         4 . The system of  claim 3 , wherein the coinhibitor comprises a transition metal, a lanthanide series metal, and/or an azole, or combination thereof. 
     
     
         5 .- 6 . (canceled) 
     
     
         7 . The system of  claim 3 , wherein a salt of the coinhibitor is present in the conversion composition in an amount of 0.001 g/L to 20 g/L. 
     
     
         8 . The system of  claim 1 , wherein the pH of the conversion composition is less than 7. 
     
     
         9 . The system of  claim 1 , wherein the ammonium of the ammonium-containing compound is present in the sealing composition in an amount of 100 ppm to 1,500 ppm based on total weight of the sealing composition. 
     
     
         10 . The system of any of the preceding claims  claim 1 , wherein the sealing composition has a pH of 5 to 11. 
     
     
         11 . The system of  claim 1 , wherein the sealing composition further comprises a Group IVB metal, a carbonate, a sulfate, a nitrate, an acetate, a hydroxide, a halogen, a silicate, a phosphate or any combination thereof. 
     
     
         12 . The system of  claim 11 , wherein the Group IVB metal is present in the sealing composition in an amount of 250 ppm to 3,800 ppm based on total weight of the sealing composition. 
     
     
         13 . (canceled) 
     
     
         14 . The system of  claim 1 , further comprising a cleaner composition, a deoxidizing composition, an indicator composition, and/or a film-forming composition. 
     
     
         15 . (canceled) 
     
     
         16 . A method of treating a substrate with the system of  claim 1 , the method comprising:
 contacting at least a portion of a surface of the substrate with the conversion composition; and   contacting at least a portion of the surface that has been contacted with the conversion composition with the sealing composition.   
     
     
         17 . The method of  claim 16 , further comprising contacting at least a portion of the surface with a cleaner composition and/or a film-forming composition. 
     
     
         18 . The method of  claim 16 , wherein the substrate is deoxidized using mechanical deoxidation and/or chemical deoxidation. 
     
     
         19 . (canceled) 
     
     
         20 . A substrate comprising a surface having a fluoride content of less than 7 atomic percent at the air-surface interface as measured by XPS depth profiling (using a Physical Electronics VersaProbe II instrument equipped with a monochromatic Al kα x-ray source (hv=1,486.7 eV) and a concentric hemispherical analyzer) and/or a fluoride content of less than 4.5 atomic percent 50 nm to 100 nm below the air-surface interface as measured by XPS depth profiling (using a Physical Electronics VersaProbe II instrument equipped with a monochromatic Al kα x-ray source (hv=1,486.7 eV) and a concentric hemispherical analyzer). 
     
     
         21 . A substrate having a surface, wherein at least a portion of the surface is treated with the system of  claim 1 . 
     
     
         22 . A substrate having a surface, wherein at least a portion of the surface is treated with the method of  claim 16 . 
     
     
         23 . The substrate of  claim 21 , wherein:
 (a) the substrate has a fluoride content of less than 7 atomic percent at the air-surface interface as measured by XPS depth profiling (using a Physical Electronics VersaProbe II instrument equipped with a monochromatic Al kα x-ray source (hv=1,486.7 eV) and a concentric hemispherical analyzer);   (b) the substrate has a fluoride content of less than 4.5 atomic percent 50 nm to 100 nm below the air-surface interface as measured by XPS depth profiling (using a Physical Electronics VersaProbe II instrument equipped with a monochromic Al kα x-ray source (hv=1,486.7 eV) and a concentric hemispherical analyzer);   (c) the substrate has a fluoride content of that is reduced by at least 30% at the air-surface interface and up to 150 nm below the air-surface interface compared to a substrate treated with the conversion composition and a sealing composition that does not contain an ammonium-containing compound as measured by XPS depth profiling (using a Physical Electronics VersaProbe II instrument equipped with a monochromatic Al kα x-ray source (hv=1,486.7 eV) and a concentric hemispherical analyzer); and/or   (d) a number of pits on the surface is reduced by at least 10% compared to a substrate treated with the conversion composition and a sealing composition that does not contain an ammonium-containing compound.   
     
     
         24 . The substrate of  claim 21 , wherein the substrate comprises a vehicle, a part, an article, or combinations thereof. 
     
     
         25 . The substrate of  claim 24 , wherein the vehicle comprises an automobile or an aircraft. 
     
     
         26 . The substrate of  claim 21 , wherein the substrate comprises aluminum or an aluminum alloy.