Corrosion resistant surface treatment and primer system for aluminum aircraft using chromium-free inhibitors

Abstract

An article includes a substrate; a first corrosion protection layer disposed on the substrate; and a second corrosion protection layer disposed on the first corrosion protection layer. The first corrosion protection layer includes a sol-gel composition and the second corrosion protection layer includes a polyurethane composition. At least one of the first or second corrosion protection layers include a corrosion inhibitor.

1 . An article, comprising:
 a first corrosion protection layer disposed on a substrate, wherein the first corrosion protection layer comprises a sol-gel composition; and   a second corrosion protection layer disposed on the first corrosion protection layer, wherein the second corrosion protection layer comprises a polyurethane composition,   wherein the second corrosion protection layer comprises a corrosion inhibitor, and wherein the corrosion inhibitor of the second corrosion protection layer comprises a plurality of thiol-containing corrosion inhibitor particles.   
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The article of  claim 1 , wherein the first corrosion protection layer does not comprise the corrosion inhibitor. 
     
     
         5 . The article of  claim 1 , wherein the second corrosion protection layer is substantially free of epoxy. 
     
     
         6 . The article of  claim 1 , wherein the sol-gel composition comprises silicon and zirconium. 
     
     
         7 . The article of  claim 1 , wherein the sol-gel composition comprises an organometallic and an organosilane. 
     
     
         8 . The article of  claim 21 , wherein the corrosion inhibitor is present in the first corrosion protection layer in an amount of from about 12 to about 45 pigment volume concentration (PVC). 
     
     
         9 . The article of  claim 1 , wherein the corrosion inhibitor is present in the second corrosion protection layer in an amount of from about 15 to about 25 pigment volume concentration (PVC). 
     
     
         10 . The article of  claim 1 , further comprising a topcoat layer disposed on the second corrosion protection layer, wherein the topcoat layer comprises a corrosion inhibitor. 
     
     
         11 . A method for coating an article, comprising:
 applying a first corrosion protection layer on a substrate, wherein the first corrosion protection layer comprises a sol-gel composition;   applying a second corrosion protection layer on the first corrosion protection layer,   wherein the second corrosion protection layer comprises a polyurethane composition,   wherein the second corrosion protection layer comprises a corrosion inhibitor, and   wherein the corrosion inhibitor of the second corrosion protection layer comprises a plurality of thiol-containing corrosion inhibitor particles.   
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . The method of  claim 11 , wherein the first corrosion protection layer does not comprise the corrosion inhibitor. 
     
     
         15 . The method of  claim 11 , wherein the second corrosion protection layer is substantially free of epoxy. 
     
     
         16 . The method of  claim 11 , wherein the sol-gel composition comprises silicon and zirconium. 
     
     
         17 . The method of  claim 11 , wherein the sol-gel composition comprises an organometallic and an organosilane. 
     
     
         18 . The method of  claim 11 , wherein the corrosion inhibitor is present in the first corrosion protection layer in an amount of from about 12 to about 45 pigment volume concentration (PVC). 
     
     
         19 . The method of  claim 11 , wherein the corrosion inhibitor is present in the second corrosion protection layer in an amount of from about 15 to about 25 pigment volume concentration (PVC). 
     
     
         20 . The method of  claim 11 , further comprising applying a topcoat layer on the second corrosion protection layer, wherein the topcoat layer comprises a corrosion inhibitor. 
     
     
         21 . The article of  claim 1 , wherein each of the first corrosion protection layer and the second corrosion protection layer comprise the corrosion inhibitor. 
     
     
         22 . The article of  claim 1 , wherein the first corrosion protection layer comprises a corrosion inhibitor and wherein the corrosion inhibitor of the first corrosion protection layer is different than the corrosion inhibitor of the second corrosion protection layer. 
     
     
         23 . The method of  claim 11 , wherein each of the first corrosion protection layer and the second corrosion protection layer comprise the corrosion inhibitor. 
     
     
         24 . The method of  claim 11 , wherein the first corrosion protection layer comprises a corrosion inhibitor and wherein the corrosion inhibitor of the first corrosion protection layer is different than the corrosion inhibitor of the second corrosion protection layer.