Abstract: Coating for high temperature gas turbine components that include a MCrAlX phase, and an aluminum-rich phase, significantly increase oxidation and cracking resistance of the components, thereby increasing their useful life and reducing operating costs. The aluminum-rich phase includes aluminum at a higher concentration than aluminum concentration in the MCrAlX alloy, and an aluminum diffusion-retarding composition, which may include cobalt, nickel, yttrium, zirconium, niobium, molybdenum, rhodium, cadmium, indium, cerium, iron, chromium, tantalum, silicon, boron, carbon, titanium, tungsten, rhenium, platinum, and combinations thereof, and particularly nickel and/or rhenium. The aluminum-rich phase may be derived from a particulate aluminum composite that has a core comprising aluminum and a shell comprising the aluminum diffusion-retarding composition.

Abstract: A method of depositing a bond coat (16) of a thermal barrier coating (TBC) system (14) for a component (10) designed for use in a hostile thermal environment. The method yields a bond coat (16) having an adequate surface roughness for adhering a plasma-sprayed ceramic layer (18), while also exhibiting high density and low oxide content. The method generally entails forming the bond coat (16) by depositing a metal powder on the substrate (12) using a plasma spray or high velocity oxy-fuel (HVOF) technique. The metal powder contains particles that are sufficiently large to incompletely melt during deposition, yielding a surface roughness of at least about 350 microinches Ra. The large particles cause the bond coat (16) to have relatively low density and a propensity to oxidize, both at the surface of the bond coat (16) and internally due to the porosity of the bond coat (16).

Abstract: A method of depositing a bond coat (16) of a thermal barrier coating (TBC) system (14) for components designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components (10) of a gas turbine engine. The method yields a bond coat (16) having an adequate surface roughness for adhering a plasma-sprayed ceramic layer (18) while also producing a bond coat (16) that is dense with low porosity, thereby yielding a thermal barrier coating system (14) that is highly resistant to spallation. The method generally entails forming the bond coat (16) by depositing two metal powders on the substrate (12) using either a vacuum plasma spraying (VPS) or high velocity oxy-fuel (HVOF) technique. The particle size distributions of the two powders are chosen to yield a bimodal (dual-peak) particle size distribution that will produce a VPS and HVOF bond coat (16) characterized by a macro-surface roughness of at least about 350 microinches Ra attributable to particles of the coarser powder.