Abstract: A corrosion resistant coating system having a first coating and a second coating. The first coating includes a matrix and corrosion resistant particles. The matrix is preferably a matrix material selected from the group consisting of silica, silicone, phosphate, chromate, and combinations thereof. The corrosion resistant particles are uniformly distributed within the matrix and provide the coating a predetermined coefficient of thermal expansion. The particles provide the first coating with corrosion resistance. The second coating is disposed on at least a portion of the first coating. The second coating includes an organic material capable of sufficiently sealing the pores of the first coating to reduce or eliminate infiltration of contaminant material, and is capable of being removed by exposure elevated temperatures.

Abstract: A corrosion resistant coating for gas turbine engine includes a glassy ceramic matrix wherein the glassy matrix is silica-based, and includes corrosion resistant particles selected from refractory particles and non-refractory MCrAlX particles, and combinations thereof. The corrosion resistant particles are substantially uniformly distributed within the matrix, and provide the coating with corrosion resistance. Importantly the coating of the present invention has a coefficient of thermal expansion (CTE) greater than that of alumina at engine operating temperatures. The CTE of the coating is sufficiently close to the substrate material such that the coating does not spall after frequent engine cycling at temperatures above 1200° F.

Abstract: A method for applying a high temperature anti-fretting wear coating is disclosed. The method includes providing a gas turbine engine blade as a substrate in which the gas turbine engine blade has a mating surface for contacting a corresponding gas turbine engine component and applying a high temperature bond coat overlying the substrate using air plasma spraying, resulting in an inspectable, repairable turbine blade.

Abstract: A corrosion resistant coating system having a first coating and a second coating. The first coating includes a matrix and corrosion resistant particles. The matrix is preferably a matrix material selected from the group consisting of silica, silicone, phosphate, chromate, and combinations thereof. The corrosion resistant particles are uniformly distributed within the matrix and provide the coating a predetermined coefficient of thermal expansion. The particles provide the first coating with corrosion resistance. The second coating is disposed on at least a portion of the first coating. The second coating includes an organic material capable of sufficiently sealing the pores of the first coating to reduce or eliminate infiltration of contaminant material, and is capable of being removed by exposure elevated temperatures.

Abstract: A metallic substrate has a substrate surface having a substrate surface of nickel, a substrate aluminum content, and other alloying elements. A maskant is applied overlying the substrate surface to produce a masked substrate surface having an exposed region and a protected region. The maskant includes a plurality of maskant particles, each particle having a maskant particle composition comprising a maskant metal selected from the group of nickel, cobalt, titanium, chromium, iron, and combinations thereof, and a maskant aluminum content. The substrate is aluminided by contacting a source of aluminum to the masked substrate surface, whereby aluminum deposits on the exposed region and does not deposit on the protected region.

Abstract: A coated article is provided with a coating stabilizing portion in a coating combination on a substrate of the article. The coating combination includes a coating diffusion portion on the substrate and an outer coating portion outwardly from the coating diffusion portion. The coating stabilizing portion is provided between the coating diffusion portion and the outer coating portion to inhibit diffusion of undesirable elements to an interface with the outer coating portion and to enhance mechanical properties.

Abstract: A metallic substrate has a substrate surface having a substrate surface of nickel, a substrate aluminum content, and other alloying elements. A maskant is applied overlying the substrate surface to produce a masked substrate surface having an exposed region and a protected region. The maskant includes a plurality of maskant particles, each particle having a maskant particle composition comprising a maskant metal selected from the group of nickel, cobalt, titanium, chromium, iron, and combinations thereof, and a maskant aluminum content. The substrate is aluminided by contacting a source of aluminum to the masked substrate surface, whereby aluminum deposits on the exposed region and does not deposit on the protected region.

Abstract: A gas turbine engine hot section component having a ceramic thermal barrier coating is repaired by removing the ceramic thermal barrier coating, removing oxidation products and corrosion products from the metallic bond coating beneath the ceramic thermal barrier coating, applying a noble metal to the component, diffusing the noble metal into the component substrate, and aluminiding the component to provide an outermost noble metal-Al layer.

Abstract: A gas turbine engine hot section component having a ceramic thermal barrier coating is repaired by removing the ceramic thermal barrier coating, removing oxidation products and corrosion products from the metallic bond coating beneath the ceramic thermal barrier coating, applying a noble metal to the component, diffusing the noble metal into the component substrate, and aluminiding the component to provide an outermost noble metal-Al layer.

Abstract: A gas turbine airfoil includes an internal cooling passage defined by an internal airfoil surface, and an external airfoil surface. The gas turbine airfoil is protected on both the internal airfoil surface and the external airfoil surface. The internal airfoil surface is protected by forming a diffusion aluminide protective layer at the internal airfoil surface of the internal cooling passage, with substantially no aluminum deposited on the external airfoil surface during the step of forming. The external airfoil surface is protected by depositing an overlay protective coating on the external airfoil surface, with substantially no aluminum or diffusion aluminide between the overlay protective coating and the external airfoil surface. The gas turbine airfoil is operated in a gas turbine engine, and may later be removed for repair.

Abstract: A method for restoring a protective coating including a metallic environmental resistant coating of a coating total thickness within a coating design thickness range on a metal substrate of an article includes the application of a replacement material to at least one discrete local surface area on which an undesirable amount of degradation has occurred. Such degradation can extend through the protective coating into the metal substrate. The degradation product can include at least one of oxidation, coating rumpling, and coating voiding, for example, rumpling or voiding of a bond coat under a ceramic thermal barrier coating (TBC). The degradation product first is conditioned at the discrete local area to expose an underlying portion while retaining at least a portion of the metallic environmental coating on surface areas adjacent the discrete surface area. Then a replacement metallic environmental resistant material is applied, retaining the coating total thickness within the coating design thickness range.

Abstract: A gamma titanium aluminide alloy article, is prepared using a piece of a gamma titanium aluminide alloy having a composition capable of forming alpha, alpha-2, and gamma phases. The alpha transus temperature of the gamma titanium aluminide alloy piece is determined. The gamma titanium aluminide alloy piece is consolidated by hot isostatic pressing at a temperature of from about 50 F. to about 250 F. below the alpha transus temperature and at a pressure of from about 10,000 to about 30,000 pounds per square inch, for a duration of from about 1 to about 20 hours. The piece is heat treated at a temperature of from about 5 F. to about 300 F. below the alpha transus temperature for a time sufficient to refine the microstructure and generate a microstructure comprising from about 10 to about 90 volume percent gamma phase. The step of heat treating is conducted at a temperature of from about 45 F. to about 200 F. above the temperature of the step of hot isostatic pressing.

Abstract: A gas turbine engine hot section component having a ceramic thermal barrier coating is repaired by removing the ceramic thermal barrier coating, removing oxidation products and corrosion products from the metallic bond coating beneath the ceramic thermal barrier coating, applying a noble metal to the component, diffusing the noble metal into the component substrate, and aluminiding the component to provide an outermost noble metal-Al layer.

Abstract: A gamma titanium aluminide alloy article is produced from a piece of cast gamma titanium aluminide alloy by consolidating the gamma titanium aluminide alloy piece at a temperature above the eutectoid to reduce porosity therein, preferably by hot isostatic pressing. The piece is first heat treated at a temperature above the eutectoid for a time sufficient to form a structure of gamma grains plus lamellar colonies of alpha and gamma phases, and thereafter second heat treated at a temperature below the eutectoid to grow gamma grains within the colony structure, thereby reducing the effective grain size of the colony structure. There may follow an additional heat treatment just below the alpha transus to reform any remaining colony structure to produce a structure having isolated alpha-two laths within gamma grains.