Abstract: A gas turbine process includes supplying a fuel to a gas turbine, combusting the fuel in the gas turbine with a hot gas path temperature reaching at least 1100° C. during operation of the gas turbine, and supplying an inhibition composition including at least one yttrium-containing inorganic compound to interact with the vanadium and inhibit vanadium hot corrosion in the gas turbine caused by vanadium as a fuel impurity in the fuel. A process includes supplying an inhibition composition including at least one yttrium-containing inorganic compound to a hot gas path or a combustor of a gas turbine. A fuel composition includes a fuel including at least one fuel impurity including vanadium and an inhibition composition including at least one yttrium-containing compound. An atomic ratio of yttrium to vanadium in the fuel composition is in a range of 1 to 1.5.

Abstract: A coating method and a coated article are disclosed. Forming a coating includes providing a substrate having a substrate surface, forming on the substrate surface at least one bond coating layer defining a bond coating surface, and forming on the bond coating surface at least one oxide coating layer defining an oxide coating surface. A coated article includes a substrate having the coating formed thereupon. The oxide coating layer is more resistive to increasing the oxide coating surface roughness (Ra) than either the bond coating layer is resistive to increasing the bond coating surface roughness (Ra) or the substrate is resistive to increasing the substrate surface roughness (Ra).

Abstract: A vanadium resistant coating system resistant to high temperature vanadium attack. The system comprises a high temperature superalloy substrate. A bond coat overlies the superalloy substrate. The bond coat may be applied in multiple layers. A ceramic coating overlies the bond coat. The ceramic coating further comprises a zirconium oxide stabilized by at least one cation selected from the group consisting of Yb3+, Lu3+, Sc3+ and Ce4+, in the amounts of about 5-10 weight percent. An overcoat may overlie the ceramic coating. The overcoat may be a sacrificial layer of YSZ infiltrated with cations having an atomic radius larger than Y3+. Alternatively, the overcoat may comprise zirconium oxide stabilized by Ce4+.

Abstract: A vanadium resistant coating system resistant to high temperature vanadium attack. The system comprises a high temperature superalloy substrate. A bond coat overlies the superalloy substrate. The bond coat may be applied in multiple layers. A ceramic coating overlies the bond coat. The ceramic coating further comprises a zirconium oxide stabilized by at least one cation selected from the group consisting of Yb3+, Lu3+, Sc3+ and Ce4+, in the amounts of about 5-10 weight percent. An overcoat may overlie the ceramic coating. The overcoat may be a sacrificial layer of YSZ infiltrated with cations having an atomic radius larger than Y3+. Alternatively, the overcoat may comprise zirconium oxide stabilized by Ce4+.

Abstract: A coating composition includes a cermet material having metal carbide phase particles with an average size of less than 5 microns. The coating has an average surface roughness of less than approximately 5 microns. A system for applying a coating to a substrate includes a spray gun configured for use with a high velocity oxygen or high velocity air fuel system. The system further includes a cermet material supplied to the spray gun, wherein the cermet material includes at least approximately 34 percent by weight of a metal carbide phase having an average particle size of less than or equal to approximately 5 microns. The metal carbide phase is dispersed in a liquid selected from the group consisting of water, alcohol, an organic combustible liquid, or an organic incombustible liquid.

Abstract: A coating composition is described, having a first coating layer which includes a nickel-chromium matrix in which metal carbide particles are dispersed; and a hard, dense second coating layer disposed over the first coating layer. The second coating layer is formed from a metal nitride-type material, and has an average roughness of less than about 80 micro-inches (Ra). Related articles and processes are also disclosed.

Abstract: A coating composition is described, having a first coating layer which includes a metallic matrix in which metal carbide particles are dispersed; and a hard, dense second coating layer disposed over the first coating layer. The second coating layer is formed from a metal nitride-type material, and has an average roughness of less than about 80 micro-inches (Ra). Related articles and processes are also disclosed.