Coating Compositions Exhibiting Corrosion Resistance Properties and Related Coated Substrates

Abstract

Coating compositions are disclosed that include corrosion resisting particles such that the coating composition can exhibit corrosion resistance properties. Also disclosed are substrates at least partially coated with a coating deposited from such a composition and multi-component composite coatings, wherein at least one coating later is deposited from such a coating composition. Methods and apparatus for making ultrafine solid particles are also disclosed.

We claim: 
     
         1 . A method of coating a substrate comprising: applying a first coating composition to at least a portion of the substrate, wherein the first coating composition comprises: epoxy functional material, organic solvent, and magnesium oxide particles; and wherein the substrate comprises a 2000 series aluminum alloy. 
     
     
         2 . The method of  claim 1 , wherein the first coating composition further comprises an amine functional material. 
     
     
         3 . The method of  claim 1 , further comprising applying an additional coating composition onto the at least partially coated substrate. 
     
     
         4 . The method of  claim 3 , wherein the additional coating composition comprises polyurethane. 
     
     
         5 . The method of  claim 1 , wherein the first coating composition has a dry film thickness of 0.5 to 1.25 mils. 
     
     
         6 . The method of  claim 1 , wherein the magnesium oxide particles have a surface area of at least 10 m 2 /g. 
     
     
         7 . The method of  claim 6 , wherein the magnesium oxide particles are platy. 
     
     
         8 . The method of  claim 6 , wherein the magnesium oxide particles are spherical. 
     
     
         9 . The method of  claim 6 , wherein the magnesium oxide particles are cubical. 
     
     
         10 . The method of  claim 6 , wherein the magnesium oxide particles are acicular. 
     
     
         11 . The method of  claim 1 , wherein the first coating composition is substantially chromate-free. 
     
     
         12 . The method of  claim 3 , wherein both the first and the additional coating compositions are substantially chromate-free. 
     
     
         13 . The method of  claim 1 , wherein the 2000 series aluminum alloy comprises an aluminum cladding. 
     
     
         14 . A coated substrate comprising:
 (a) a 2000 series aluminum alloy;   (b) a first cured thermoset coating that is deposited from a first coating composition comprising an epoxy functional material and magnesium oxide particles.   
     
     
         15 . The coated substrate of  claim 14 , wherein the first coating composition further comprises an amine functional material. 
     
     
         16 . The coated substrate of  claim 14 , further comprising:
 (c) a second coating deposited from a second coating composition on at least a portion of the first cured thermoset coating.   
     
     
         17 . The coated substrate of  claim 16 , wherein the second coating composition comprises polyurethane. 
     
     
         18 . The coated substrate of  claim 14 , wherein the first coating composition has a dry film thickness of 0.5 to 1.5 mils. 
     
     
         19 . The coated substrate of  claim 14 , wherein the magnesium oxide particles have a surface area of at least 10 m 2 /g. 
     
     
         20 . The coated substrate of  claim 19 , wherein the magnesium oxide particles are platy. 
     
     
         21 . The coated substrate of  claim 19 , wherein the magnesium oxide particles are spherical. 
     
     
         22 . The coated substrate of  claim 19 , wherein the magnesium oxide particles are cubical. 
     
     
         23 . The coated substrate of  claim 19 , wherein the magnesium oxide particles are acicular. 
     
     
         24 . The coated substrate of  claim 14 , wherein the first coating composition is substantially chromate-free. 
     
     
         25 . The coated substrate of  claim 16 , wherein both the first and second coating compositions are substantially chromate-free. 
     
     
         26 . The coated substrate of  claim 14 , wherein the 2000 series aluminum alloy comprises an aluminum cladding. 
     
     
         27 . The coated substrate of  claim 14 , wherein the substrate has better corrosion resistance than a substrate coated with a cured thermoset coating having the same epoxy functional material but lacking the magnesium oxide particle as measured by ASTM B 117 after 1000 hours. 
     
     
         28 . The coated substrate of  claim 16 , further comprising a surface treatment applied to the substrate prior to application of the first cured thermoset coating, and wherein the surface treatment, first coating composition and the second coating composition are substantially chromate-free. 
     
     
         29 . The coated substrate of  claim 16 , wherein the second coating is an aerospace coating. 
     
     
         30 . A method for enhancing the corrosion resistance of a substrate comprising 2000 series aluminum alloy, comprising coating at least a portion of the substrate with a composition comprising:
 (a) an epoxy functional material;   (b) organic solvent; and   (c) magnesium oxide particles.