Patent attributes
In general, the present invention provides coating systems and processes for applying a selected coating system on a metallic substrate. The coating system includes two or more coating layers. A first layer comprises a MCrAl(Y,Hf)-type coating. The MCrAl(Y,Hf) coating is overlaid with a second coating composition that includes a metallic composition different from the MCrAl(Y,Hf) coating composition and includes one or more of: a platinum, silicon containing composition; a platinum, silicon, aluminum containing composition; a platinum, silicon, chromium containing composition; an aluminum, silicon containing composition; and an aluminum, silicon, chromium containing composition; each optionally combined with one or more of chromium, hafnium, lanthanum, manganese, yttrium and mixtures of these metals. Additionally the platinum in the metallic compositions can be exchanged in whole or in part by another noble metal. The resulting coating composition is subsequently heat treated to provide a diffused multilayer corrosion-resistant coating.
