Patent ID: 8592042

Claim:
A method for coating a metallic substrate consisting essentially of: providing an aqueous mixture devoid of pigment and metallic flakes consisting essentially of: about 2 vol % to about 50 vol % organosilane, about 0.3 vol % to about 25 vol % metal alkoxide; and about 0.1 vol % to about 30 vol % organic complexing agent; depositing the aqueous mixture on a surface of the metallic substrate, the surface having a metallic appearance; and curing the mixture to form a coating on the surface of the substrate to form an adherent oxidation and discoloration resistant coating thereon that reduces airflow obstruction over the substrate and retains the metallic appearance of the surface; wherein the coating has a thickness of 1 to about 25 microns and maintains the metallic appearance and the properties of resistance to oxidation and resistance to discoloration when exposed to temperature up to about 700° F.