摘要:
The present invention provides for a squealer tip to include some proportion of a highly oxidation-resistant material, and a method for casting same, such that if any environmental coating were removed, the tip would retain some increased level of environmental resistance. The oxidation-resistant material optionally may also be a high abrasion resistance material, such that recession of the tip due to rubbing against a stator would be reduced. In a preferred embodiment, an abrasion-resistant and/or oxidation-resistant material is placed and suitably anchored into the tip region of a wax precursor used to cast a turbine airfoil. During the casting operation, the abrasion-resistant and/or oxidation-resistant material is not completely melted. As the alloy used to form the majority of the turbine blade solidifies, the abrasion and/or oxidation resistant material is incorporated into the turbine airfoil by the solidification of the alloy around it.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A superalloy weld composition includes: up to about 5.1 wt % Co; about 7.2 to about 9.5 wt % Cr; about 7.4 to about 8.4 wt % Al; about 4.3 to about 5.6 wt % Ta; about 0.1 to about 0.5 wt % Si; about 0.1 to about 0.5 wt % Hf; up to about 0.05 wt % C; up to about 0.05 wt % B; about 0 to about 2.2 Re; about 2.7 to about 4.4 wt % W; and balance Ni and typical impurities.
摘要:
A group of alloys suitable for use in a high-temperature, oxidative environment, a protective coating system comprising a diffusion barrier that comprises an alloy selected from the group, an article comprising the diffusion barrier layer, and a method for protecting an article from a high-temperature oxidative environment comprising disposing the diffusion barrier layer onto a substrate are presented.
摘要:
A composition of matter is about 1 to about 3 percent rhenium, from about 6 to about 9 percent aluminum, from 0 to about 0.5 percent titanium, from about 4 to about 6 percent tantalum, from about 12.5 to about 15 percent chromium, from about 3 to about 10 percent cobalt, from about 2 to about 5 percent tungsten, from 0 to about 0.2 percent hafnium, from 0 to about 1 percent silicon, from 0 to about 0.25 percent molybdenum, from 0 to about 0.25 percent niobium, balance nickel and minor elements. The composition is preferably made into a substantially single crystal article, such as a component of a gas turbine engine.
摘要:
A protected article includes a nickel-base superalloy substrate, an interlayer overlying the substrate, and a protective layer overlying the interlayer. The protective layer has a composition comprising at least one of rhodium, platinum, palladium, and ruthenium. In one composition, palladium is present in an amount of from about 1 to about 41 atomic percent; platinum is present in an amount of about (40+atomic percent palladium) atomic percent for palladium ranging from about 1 atomic percent to about 14 atomic percent and up to about 54 atomic percent for palladium ranging from about 15 atomic percent up to about 41 atomic percent; rhodium is present in an amount of at least about 24 atomic percent; zirconium, hafnium, titanium, and mixtures thereof are present in an amount of from zero up to about 5 atomic percent; and ruthenium is present in an amount of from zero up to about 5 atomic percent, balance impurities. The interlayer has a coefficient of thermal expansion intermediate between that of the substrate and that of the protective layer. The protected article is fabricated by furnishing the substrate, applying the interlayer over the substrate, and applying the protective layer over the interlayer. The application of the protective layer may be, for example, by welding or attachment of a solid piece.
摘要:
A barrier coating is disclosed, containing about 15 atom % to about 95 atom % chromium; and about 5 atom % to about 60 atom % of at least one of rhenium, tungsten, and ruthenium. Nickel, cobalt, iron, and aluminum may also be present. The barrier coating can be disposed between a metal substrate (e.g., a superalloy) and an oxidation-resistant coating, preventing the substantial diffusion of various elements at elevated service temperatures. A ceramic overcoat (e.g., based on zirconia) can be applied over the oxidation-resistant coating. Related methods for applying protective coatings to metal substrates are also described.
摘要:
An article for use in a hot gas path of a gas turbine assembly, a metallic skin for such an article, and a method for making such an article are presented with, for example, the article comprising a spar, the spar providing mechanical support for the article and comprising a cooling fluid delivery system, a top end, and a bottom end; a standoff structure attached to the spar, the standoff structure comprising a plurality of spacing elements in a spaced-apart relation to each other, the spacing elements having first ends adjacent to the spar and second ends opposite to the first ends; a skin conformally surrounding the spar and the standoff structure, the skin comprising a top end and a bottom end, wherein the standoff structure separates the spar and the skin, wherein the plurality of spacing elements is disposed with an inner surface of the skin adjacent to the second ends of the spacing elements to form a plurality of plena between the spar and the skin, the plena in fluid communication with the cooling fluid delivery system, the skin comprising at least one metal selected from the group consisting of Rh, Pd, and Pt; and a base connecting the bottom end of the spar and the bottom end of the skin.