Abstract: A coating system on a superalloy or silicon-containing substrate of an article exposed to high temperatures. The coating system includes a coating layer that overlies the substrate and is susceptible to hot corrosion promoted by molten salt impurities. A corrosion barrier coating overlies the coating layer and contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer.

Abstract: A system for passivating a plurality of hollow copper strands in a stator water cooling system including; a first storage tank containing a cleaning solution, a second storage tank containing rinsing water; a third storage tank containing a passivation solution; a plurality of conduits connecting the first, second, and third storage tanks in a closed loop with the plurality of hollow copper strands; and an alkaline pump for pumping the cleaning solution, the rinsing water, and the passivation solution through the closed loop.

Abstract: A treatment process, an oxide-forming treatment composition, and a treated component are disclosed. The treatment process includes applying an oxide-forming treatment composition to a ceramic coating and heating the oxide-forming treatment composition to form an oxide within the ceramic coating. The oxide-forming treatment composition includes a solute and a corrosion inhibitor. The oxide-forming treatment composition is super-saturated with the corrosion inhibitor. The treated component includes a ceramic coating and one or both of a corrosion inhibitor and an oxide formed by an oxide-forming treatment composition having the corrosion inhibitor. The corrosion inhibitor and the oxide-forming treatment composition are within the ceramic coating.

Abstract: A coating system on a superalloy or silicon-containing substrate of an article exposed to high temperatures. The coating system includes a coating layer that overlies the substrate and is susceptible to hot corrosion promoted by molten salt impurities. A corrosion barrier coating overlies the coating layer and contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer.

Abstract: A method of fabricating a component for a gas turbine engine is provided. The method includes applying a bond coat to at least a portion of the component, applying a dense vertically cracked (DVC) thermal barrier coating to at least a portion of the bond coat using a spray mechanism positioned a first distance from the component, and overlying at least a portion of the DVC thermal barrier coating with a soft coat thermal barrier coating using a spray mechanism that is positioned a second distance away from the component, wherein the second distance is greater than the first distance to facilitate adherence of the soft coating thermal barrier coating to the DVC thermal barrier coating.

Abstract: A method of fabricating a component for a gas turbine engine is provided. The method includes applying a bond coat to at least a portion of the component, applying a dense vertically cracked (DVC) thermal barrier coating to at least a portion of the bond coat using a spray mechanism positioned a first distance from the component, and overlying at least a portion of the DVC thermal barrier coating with a soft coat thermal barrier coating using a spray mechanism that is positioned a second distance away from the component, wherein the second distance is greater than the first distance to facilitate adherence of the soft coating thermal barrier coating to the DVC thermal barrier coating.

Abstract: A method for metallurgically bonding a stator bar to a coupling to reduce the incidence of leak paths resulting from corrosion. The stator bar comprises strands through which a liquid coolant can flow. Adjacent ends of the strands are received in an interior cavity of the coupling through an opening in the coupling. A joining material is provided on a first portion of the stator bar within the coupling opening and adjacent the ends of the strands. The first portion is heated to melt the joining material. At essentially the same time, a second portion of the stator bar outside the coupling is also heated. Once the joining material is suitably molten, the first portion is allowed to cool while the second portion remains heated, thereby causing the joining material nearest the ends of the strands to solidify first.

Abstract: A coated article comprises a substrate; and a multilayer thermal barrier coating disposed on the substrate, the multilayer thermal barrier coating comprising at least a first layer comprising a first ceramic composition having a thermal conductivity less than 1 W/m° K; a second layer having an erosion resistance greater than or equal to dense vertically cracked 8% yttrium stabilized zirconia, wherein percent is based on a total weight of yttrium and zirconia, and a third layer comprising the first ceramic composition or the second composition, wherein the first, second, and third layers are arranged such that the first ceramic composition and the second composition are in alternating layers.

Abstract: A coating and method for overcoating a TBC on a component used in a high-temperature environment, such as the combustor section of an industrial gas turbine. The coating defines the outermost surface of the component and is formed of at least two layers having different compositions. An inner layer of the coating contains alumina in a first silica-containing matrix material that is free of zinc titanate. An outer layer of the coating contains alumina, a glass material, and zinc titanate in a second silica-containing matrix material. The outer layer of the coating has a surface roughness of not greater than three micrometers Ra and forms the outermost surface of the component. The coating reduces the component temperature by reducing the convective and radiant heat transfer thereto.

Abstract: A method includes blasting the interior surfaces of the fitting to stator bar strand joint with CO2 pellets to remove loose copper oxide which otherwise would interfere with proper sealing between an epoxy and the copper surfaces of the joint. After cleaning the surfaces and applying air under pressure to remove particulate material, epoxy is applied to the brazed joints followed by an evacuation of the fitting to strand joint. Subsequent release of the vacuum ensures that the epoxy fills in all crevices or cracks at the joint surfaces and minimizes or eliminates any tendency of the epoxy to delaminate.

Abstract: A compressor forward stub shaft comprising a plurality of axially spaced, annular rows of dovetail grooves, at least a first and a second of the plurality of rows having dovetail slots coated in part with an anti-wear coating.

Abstract: A method for metallurgically bonding a stator bar to a coupling to reduce the incidence of leak paths resulting from corrosion. The stator bar comprises strands through which a liquid coolant can flow. Adjacent ends of the strands are received in an interior cavity of the coupling through an opening in the coupling. A joining material is provided on a first portion of the stator bar within the coupling opening and adjacent the ends of the strands. The first portion is heated to melt the joining material. At essentially the same time, a second portion of the stator bar outside the coupling is also heated. Once the joining material is suitably molten, the first portion is allowed to cool while the second portion remains heated, thereby causing the joining material nearest the ends of the strands to solidify first.

Abstract: A method for metallurgically bonding a stator bar to a coupling to reduce the incidence of leak paths resulting from corrosion. The stator bar comprises strands through which a liquid coolant can flow. Adjacent ends of the strands are received in an interior cavity of the coupling through an opening in the coupling. A joining material is provided on a first portion of the stator bar within the coupling opening and adjacent the ends of the strands. The first portion is heated to melt the joining material. At essentially the same time, a second portion of the stator bar outside the coupling is also heated. Once the joining material is suitably molten, the first portion is allowed to cool while the second portion remains heated, thereby causing the joining material nearest the ends of the strands to solidify first.

Abstract: A method is disclosed to dissolve cupric oxide (CuO) deposits on a strainer in a stator water cooling system (SWCS) of an industrial electrical power generator. The method injects carbon dioxide (CO2) into the coolant to increase the CuO solubility of the coolant. By increasing the solubility, the CuO level in the coolant is less than saturated. The unsaturated coolant dissolves the CuO deposits on the strainer.

Abstract: The present invention provides a method of removing copper oxide deposits from stator water cooling system piping material surfaces. The present invention disconnects the generator from the stator water cooling system, connects bridging piping to the stator water cooling system at the points from which the generator was disconnected to allow the stator water cooling system to operate without the generator, provides a sufficient amount of an aqueous solution of an agent which dissolves or removes copper oxide deposits from piping material surfaces for a time sufficient to dissolve or remove substantially all copper oxide deposits, and rinses the piping material surfaces with sufficient water until the output water from the rinsing of the piping material surfaces is essentially neutral.

Abstract: A rigid die insert for forming and shaping a working material. The rigid die insert comprises a nickel-base superalloy, preferably Rene 95. A plurality of gamma prime particles are uniformly distributed throughout the rigid die insert, which has a Rockwell hardness Rc of between about 48 and about 52. The invention also includes a method of treating a rigid die insert comprising a nickel-base superalloy to reduce crack propagation and raise yield stress. The method comprises the steps of: providing the rigid die insert; dissolving larger gamma-prime particles in the rigid die insert; and growing additional gamma-prime particles of smaller particle size in the rigid die insert, whereby the particle size of each of the plurality of gamma-prime particles is refined, thereby reducing crack propagation and raising the yield stress of the rigid die insert. A method of refining the particle size of gamma-prime particles in a Rene 95 superalloy is also disclosed.

Abstract: A method is disclosed to dissolve cupric oxide (CuO) deposits on a strainer in a stator water cooling system (SWCS) of an industrial electrical power generator. The method injects carbon dioxide (CO2) into the coolant to increase the CuO solubility of the coolant. By increasing the solubility, the CuO level in the coolant is less than saturated. The unsaturated coolant dissolves the CuO deposits on the strainer.

Abstract: The present invention provides a creep resistant zirconium alloy comprising a coarse grained lath alpha microstructure. The microstructure can include small second phase precipitates. The small second phase precipitates can have a diameter less than 0.15 &mgr;m. The microstructure can be partially recrystallized. The microstructure is an acicular structure and can include a lath spacing within the range from about 0.5 to about 3.0 &mgr;m. The microstructure is an acicular structure and can include a lath spacing within the range from about 0.5 to about 3.0 &mgr;m. The present invention provides a nuclear fuel cladding comprising an annular layer of the creep resistant zirconium alloy.

Abstract: The present invention provides a method of removing copper oxide deposits from stator water cooling system piping material surfaces. The present invention disconnects the generator from the stator water cooling system, connects bridging piping to the stator water cooling system at the points from which the generator was disconnected to allow the stator water cooling system to operate without the generator, provides a sufficient amount of an aqueous solution of an agent which dissolves or removes copper oxide deposits from piping material surfaces for a time sufficient to dissolve or remove substantially all copper oxide deposits, and rinses the piping material surfaces with sufficient water until the output water from the rinsing of the piping material surfaces is essentially neutral.

Abstract: A double wall hot gas path part for turbines, such as an airfoil, combustor, duct or shroud, comprises an outer skin and an inner support wall that are metallurgically bonded to one another. The double wall contains integral channels for passage of cooling air adjacent to the skin. The skin may be a metal alloy skin or a microlaminate structure, including microlaminate composite structures. Microlaminate composites typically have a lower density than that of the material used for the support wall, and a simplified internal geometry, which promote weight reductions in the parts and increases in engine operating efficiency.