Abstract: Gas turbine engine turbine blade includes a silicon-modified aluminide coating on at least an under platform region formed from a slurry composition being substantially free of hexavalent chromium. The silicon-modified aluminide coating provides oxidation resistance comparable to PtAl coatings without adding a weight penalty.

Abstract: A method for repairing a nickel-base superalloy article, such as a gas turbine stationary flowpath shroud having flowpath cooling holes therein that has previously been in service, includes the steps of providing the nickel-base superalloy article that has previously been in service; and applying a restoration to a surface of the article. The restoration is applied by the steps of providing a restoration nickel-base alloy, wherein the restoration nickel-base alloy preferably has no more than about 15 weight percent chromium and no more than about 0.01 percent yttrium, thereafter applying a restoration coating of the restoration nickel-base alloy to the surface of the article by a hyper-velocity oxyfuel metal spray process or a low-pressure plasma spray process, and thereafter heating the article with the restoration coating applied to the surface thereof to a sufficiently high temperature to diffusion bond the restoration coating to the surface of the article. The article is then returned to service.

Abstract: Formation of a silicon-modified aluminide coating on the under platform region of a superalloy gas turbine engine blade for improved corrosion and oxidation resistance. The coating is formed from a slurry composition including colloidal silica and aluminum-based powder and is substantially free of hexavalent chromium. The coating provides aluminum and silicon content in the outer 25% of a coating thickness of at least about 20% by weight aluminum and about 3% by weight silicon.

Abstract: A method for repairing a nickel-base superalloy article, such as a gas turbine stationary flowpath shroud having flowpath cooling holes therein that has previously been in service, includes the steps of providing the nickel-base superalloy article that has previously been in service; and applying a restoration to a surface of the article. The restoration is applied by the steps of providing a restoration nickel-base alloy, wherein the restoration nickel-base alloy preferably has no more than about 15 weight percent chromium and no more than about 0.01 percent yttrium, thereafter applying a restoration coating of the restoration nickel-base alloy to the surface of the article by a hyper-velocity oxyfuel metal spray process or a low-pressure plasma spray process, and thereafter heating the article with the restoration coating applied to the surface thereof to a sufficiently high temperature to diffusion bond the restoration coating to the surface of the article. The article is then returned to service.

Abstract: Formation of a silicon-modified aluminide coating on the under platform region of a superalloy gas turbine engine blade for improved corrosion and oxidation resistance. The coating is formed from a slurry composition including colloidal silica and aluminum-based powder and is substantially free of hexavalent chromium. The coating provides aluminum and silicon content in the outer 25% of a coating thickness of at least about 20% by weight aluminum and about 3% by weight silicon.

Abstract: A nickel-base superalloy article, such as a gas turbine stationary flowpath shroud that has previously been in service, is repaired by applying a restoration coating to a surface of the article. The restoration coating is applied by providing a precursor mixture, wherein the precursor mixture has no more than about 15 weight percent chromium and no more than about 0.01 percent yttrium, and wherein the precursor mixture includes a higher-melting-point alloy component and a lower-melting-point alloy component. The precursor mixture is applied to the surface of the article, in a form such as a preform of the alloy components. The article with the precursor mixture applied to the surface thereof is heated to a sufficiently high temperature to melt the lower-melting-point alloy component, thereby forming the restoration coating on the surface of the article.

Abstract: The present invention provides for a method to reduce the strength of the honeycomb of a jet turbine stator, increasing its machinability, with a resultant reduction in measured peak tooth temperature, while maintaining or even improving its high temperature capability, so as not to limit its operating environment. The air seal functionality is unaffected, and even improved in some instances. The machinability of the honeycomb is increased by using a light element diffused into the honeycomb ribbon to produce the effect of reducing its strength and ductility while maintaining the environmental resistance needed. The present invention also includes the stator honeycomb produced by the foregoing method.

Abstract: The present invention provides for a method to reduce the strength of the honeycomb of a jet turbine stator, increasing its machinability, with a resultant reduction in measured peak tooth temperature, while maintaining or even improving its high temperature capability, so as not to limit its operating environment. The air seal functionality is unaffected, and even improved in some instances. The machinability of the honeycomb is increased by using a light element diffused into the honeycomb ribbon to produce the effect of reducing its strength and ductility while maintaining the environmental resistance needed. The present invention also includes the stator honeycomb produced by the foregoing method.