Abstract: An article protected by a thermal barrier coating system is fabricated by providing an article substrate having a substrate surface, thereafter depositing a bond coat on the substrate surface, the bond coat having a bond coat surface, and thereafter processing the bond coat to flatten the bond coat surface. A thermal barrier coating is deposited overlying the bond coat surface. The thermal barrier coating is yttria-stabilized zirconia having a yttria content of from about 3 percent by weight to about 5 percent by weight of the yttria-stabilized zirconia.

Abstract: A highly porous alumina material and a method for applying such material that is useful in the hot section of a jet aircraft engine. In order to manufacture the porous alumina, an aluminum-based metal/alumina material known in the art is first placed onto a metal alloy substrate. The aluminum-based metal is then dissolved using a solution that will not affect the alumina or the underlying substrate. The alumina is then washed with deionized water and dried. The resulting alumina has a porosity in the range of about 20% to about 45%. The alumina has globular interconnected surface features in the range of about 0.5 &mgr;m to about 20 &mgr;m.

Abstract: A steel article is fabricated by providing an iron-base alloy having less than about 0.5 weight percent aluminum, melting the alloy to form a melt, adding calcium to the melt, thereafter adding aluminum to the melt to increase the aluminum content of the melt to more than about 0.5 weight percent aluminum, and casting the melt to form a casting. Other calcium additions may be made simultaneously with the adding of aluminum, and after the adding of aluminum but before casting the melt. The calcium additions deoxidize the melt to minimize the formation of clustered aluminum-oxygen-based inclusions.

Abstract: A built-up gas turbine component is prepared by providing a gas turbine component having a component surface and being made of a component base metal having a component base metal composition. A buildup tape is supplied having a net metallic buildup composition different from the component base metal composition. The buildup tape includes a first metallic constituent having a first melting point, and a second metallic constituent having a second melting point. The first metallic constituent and second metallic constituent together have the net metallic buildup composition. A nonmetallic binder binds together the first metallic constituent and the second metallic constituent. The buildup tape is applied to the component surface and heated to a brazing temperature greater than the first melting point and less than the second melting point.

Abstract: A flexible circuit compression connector system utilized to electrically connect together conductive pads disposed on a rigid printed circuit board, the connector system comprising a flexible insulating substrate having conductive material at a plurality of preselected positions and a conductive line extending between at least two of the preselected positions, a plurality of contacts, each contract secured to the flexible substrate at each of the preselected positions having conductive material, a compression assembly that includes a resilient compression mat and means for aligning the flexible substrate of the compression assembly and the rigid substrate together so that the resilient compression mat urges the contacts secured to the flexible substrate against the conductive pads on the printed circuit board.

Abstract: An environmental coating is applied to the surface of a titanium-base alloy substrate to protect the surface from oxidation, corrosion, erosion, and other damage. The coating is a mixture of a metal and a ceramic, each selected to contribute to the protective function. The proportions of the metal and the ceramic in the coating are selected such that the coefficient of thermal expansion of the coating is about the same as the coefficient of thermal expansion of the substrate.

Abstract: A method for producing apertures in hot section components of gas turbine engines made from ceramic matrix composites that have at least one oxidizable component. The method involves forming the apertures using a laser beam controlled by parameters that ablate the ceramic matrix composite in the path of the beam, while simultaneously heating the matrix material, SiC or SiN, to a sufficient temperature to oxidize it to form a silica. Sufficient heat is supplied by the beam to melt the silica to cause it to flow. The melted silica is quickly solidified as recast silica along the walls of the newly created aperture before it has an opportunity to flow and form undesirable geometries. The wall of the aperture is formed of recast silica that is a smooth surface and that forms an oxidation barrier to inhibit any further oxidation of the underlying composite as it is exposed to the high temperatures and oxidative, corrosive atmosphere of an operating gas turbine.

Abstract: A method for producing a turbine airfoil that is coated with a beta phase, high aluminum content coating, such as substantially stoichiometric NiAl, and which has a surface finish suitable for application of a ceramic topcoat. The method involves impacting the coating with preselected particles of a preselected size so that the brittle coating is not adversely affected by chipping or breakage. The impacting produces a surface finish of 120 micro-inches or better so that a ceramic thermal barrier layer can be applied over the coating. The preferred method of improving the surface finish utilizes steel balls having a diameter of about 0.033″ and a peening intensity of no greater than about 6A.

Abstract: A differential thickness pattern can be induced in a coating that is sprayed on an aircraft engine part using a robotic system. The robotic system includes a spray mechanism with a triggering device to spray the coating on the aircraft engine part and a controller. The controller is used to move the spray mechanism along a predetermined path and to activate and deactivate the triggering device. To obtain the differential thickness pattern, a predetermined profile of the aircraft engine part corresponding to areas of the aircraft engine part requiring a thicker coating is integrated into a control program used by the controller. The controller uses the control program to activate and deactivate the triggering mechanism to limit the spraying of the coating to only those areas of the part in the predetermined profile to obtain a different coating thickness.

Abstract: A gas turbine blade which has previously been in service is protected by cleaning the gas turbine blade, and then first depositing a platinum first layer on the airfoil and the platform of the gas turbine blade. Thereafter, a platinum second layer is deposited over the platform but not the airfoil. A platinum-aluminide protective coating is formed by depositing an aluminum-containing layer overlying both the platform and the airfoil and interdiffusing the platinum and the aluminum.

Abstract: A gas turbine component such as a turbine blade is clamped into a fixture having a base upon which a remainder of the fixture is supported, a stop which limits the movement of the gas turbine component, and two clamp arms affixed to the base and controllably clamping against the lower side of the platform of the gas turbine component to force the gas turbine component against the stop. When the gas turbine component is clamped in this position, its root may be readily shaped as by grinding.

Abstract: An article having a protective coating is fabricated by providing an article substrate having a substrate surface; and thereafter producing a flattened protective coating on the substrate surface. The step of producing the flattened protective coating includes the steps of depositing a protective coating on the substrate surface, the protective coating having a protective-coating surface, and processing the protective coating to achieve the flattened protective-coating surface. The protective coating is thereafter optionally controllably oxidized. The article substrate and protective coating have an average sulfur content of less than about 10 parts per million by weight at depths measured from the protective-coating surface to a depth of about 50 micrometers below the protective-coating surface.

Abstract: Apparatus for controlled-atmosphere brazing of parts or components having cross-sectional dimensions of up to twenty-four inches. The apparatus maintains the components or parts at a uniform temperature during the brazing cycle. The apparatus includes a susceptor having a physical boundary that separates an interior of the susceptor from its exterior. While there is no limitation upon the length of the parts or components that can be brazed, the wall of the susceptor formed as a physical boundary has an internal diameter that limits the maximum cross-sectional dimension of the parts or components that are to be brazed, so that the parts or components reside within the interior of the susceptor. A heating source for heating the susceptor is provided. The heating source is capable of heating the susceptor sufficiently so that the interior of the susceptor can reach a temperature sufficient to braze the components inside the susceptor.

Abstract: Non-spherical particles including a major dimension, for example flakes of material, are positioned with the major dimension oriented generally along an article surface in respect to which the particle is disposed. The particles, disposed in a fluid medium, the viscosity of which can be increased to secure the particles in position, are positioned using a force on the particles. The force includes torque force from a magnetic field, force from flow of the fluid medium, the force of gravity, and the force of surface tension alone or in combination with the force of gravity.

Abstract: A turbine blade or turbine vane includes a metallic nonfoam region, and a ceramic foam region joined to the metallic region. The ceramic foam region is an open-cell solid ceramic foam made of ceramic cell walls having an intracellular volume therebetween. The ceramic is preferably alumina. The intracellular volume may be empty porosity, or an intracellular metal such as an intracellular nickel-base superalloy.

Abstract: A rotary compressor having a housing with a motor and an internal accumulator located on the low pressure side and an oil sump located on the high pressure side. A sealing means positioned within the housing defines a first chamber and a second chamber. The sealing means substantially maintains the pressure differential between the chambers by segregating high pressure fluid in the second chamber from low pressure fluid in the first chamber. The fluid entering the housing is separated into a gas portion and a liquid portion, the liquid portion being directed downward toward the motor to provide cooling for the motor while the gas portion is directed to a compressor portion. The liquid portion collects about the motor above the sealing means. An orifice or aperture through the sealing means allows liquid collected above the sealing means to be reintroduced into the compressor suction inlet and metered into the refrigerant gas in a controlled fashion and resupply the sump with lubricant.

Abstract: A nickel-base superalloy article has a surface protective layer comprising nickel, from about 20 to about 35 weight percent aluminum, and from about 0.5 to about 10 weight percent rhenium. The protective layer, which is preferably an overlay coating of the beta (&bgr;) phase NiAl form, is formed by depositing nickel, aluminum, rhenium, and modifying elements onto the substrate surface. A ceramic layer may be deposited overlying the protective layer.

Abstract: A pull-down control algorithm for an HVAC refrigeration system is provided. The control algorithm utilizes a fuzzy logic methodology to automatically adjust a flow of refrigerant in the system during a pull-down to maintain a desired pull-down rate. The desired pull-down rate is decreased proportionately as the temperature of the fluid being pulled down approaches a desired operating setpoint to avoid or minimize any overshoot of the operating setpoint. The desired pull-down rate is obtained by adjusting a rate sensitivity factor used in the control algorithm. When the temperature of the fluid being pulled down is above a predetermined value from the operating setpoint, the control algorithm uses a fuzzy logic methodology to determine a rate sensitivity that results in the desired pull-down rate that approaches the operating setpoint without overshoot.

Abstract: An improved method for applying a ceramic material, such as a thermal barrier coating to an article. A method for applying a ceramic material as a coating to a substrate article in which the thermal conductivity of the ceramic material is reduced or lowered is provided. The thermal conductivity of a coating applied by a physical vapor deposition (PVD) method is dependent upon its distance from the source(s) of material used for the coating. The thermal conductivity of the applied coating is altered by adjusting the position of the article undergoing the PVD process by increasing the distances of the article or workpiece from the ingot or source of ceramic material to provide a coating of lower thermal conductivity. In accordance with the present invention, the article to be coated is positioned at a distance required to achieve at least a 10% reduction in the thermal conductivity of the applied coating.

Abstract: A gas turbine airfoil has an external surface and an internal passage therethrough. The internal passage is selectively coated by providing a source of a flowable precursor coating material in contact with the internal passage of the airfoil, and providing a coating prevention structure overlying at least a portion of the external surface. The flowable precursor coating material is flowed from the source of the flowable precursor coating material and through the internal passage of the airfoil. The coating prevention structure prevents contact of the flowable precursor coating material with the external surface of the airfoil.