Abstract: A method for improving the thermal fatigue life of a thermal barrier coating (TBC) deposited on an aluminide bond coat through a process by which the surface morphology of the aluminide bond coat is modified to eliminate or at least reduce oxidation and oxidation-induced convolutions at the alumina-bond coat interface, as explained more fully below. The bond coat is deposited to have generally columnar grains and grain boundary ridges at its surface, and is then peened at an intensity sufficient to flatten at least some of the grain boundary ridges, but insufficient to cause recrystallization of the bond coat when later heated, such as during deposition of the thermal barrier coating. In so doing, the original surface texture of the bond coat is altered to be smoother where the grain boundaries meet the bond coat surface, thereby yielding a smoother bond coat surface where the critical alumina-bond coat interface will exist following oxidation of the bond coat.

Abstract: A process for casting and preparing an ingot of a beta-phase NiAl-based material, particularly for use in PVD coating processes. The method entails melting a nickel-aluminum composition having an aluminum content below that required for stoichiometric beta-phase NiAl intermetallic so as to form a melt that includes nickel and Ni3Al. Aluminum is then added to the melt, causing an exothermic reaction between nickel and aluminum as the melt equilibrium shifts from Ni3Al to NiAl. However, the aluminum is added at a rate sufficiently low to avoid a violent exothermic reaction. The addition of aluminum continues until sufficient aluminum has been added to the melt to yield a beta-phase NiAl-based material. The beta-phase NiAl-based material is then solidified to form an ingot, which is then heated and pressed to close porosity and homogenize the microstructure of the ingot.

Abstract: A coating system having a low thermal conductivity, and a method by which the low thermal conductivity of the coating system is maintained through the development of cracks within a thermal-insulating layer of the coating system. The thermal-insulating layer is a mixture of two or more materials with different coefficients of thermal expansion (CTE). The materials of the thermal-insulating layer are selected and combined so that a low thermal conductivity is maintained for the coating system as the result of cracks developing and propagating from interfaces between the materials when the coating system is subjected to heating and cooling cycles.

Abstract: A method of preventing or at least reducing the likelihood of bridging between adjacent micro-scale polycrystalline structures, and particularly to reducing electrical shorting between adjacent metallization lines of a microcircuit. The method generally entails forming a multilayer structure that comprises a polycrystalline layer and at least one constraining layer, and then patterning the multilayer structure to yield a first line and a second line that is narrower in width than the first line. The first line has a patterned edge that is spaced apart from a patterned edge of the second line, so that the first and second lines are electrically insulated from each other. One or more features associated with the first line are then formed that prevent bridging between the first and second lines if excessive lateral grain growth subsequently occurs along the patterned edge of the first line.

Abstract: A thermal barrier coating system and a method for forming the coating system on an article designed for use in a hostile thermal environment. The method is particularly directed to a coating system that includes a plasma-sprayed MCrAlY bond coat on which a thermal-insulating APS ceramic layer is deposited, in which the oxidation resistance of the bond coat and the spallation resistance of the ceramic layer are substantially increased by vapor phase aluminizing the bond coat. The bond coat is deposited to have a surface area ratio of at least 1.4 and a surface roughness of at least 300 &mgr;inch Ra in order to promote the adhesion of the ceramic layer. The bond coat is then overcoat aluminized using a vapor phase process that does not alter the surface area ratio of the bond coat. This process is carried out at relatively low temperatures that promote inward diffusion of aluminum relative to outward diffusion of the bond coat constituents, particularly nickel and other refractory elements.

Abstract: A gas-liquid contactor for removing gases and particulate matter from flue gases produced by processing operations of the type carried out in utility and industrial plants. The contactor is generally an open spray absorber having a spray tower (110) whose walls (114) form a passage within the tower (110). Flue gases are introduced into the tower (110) so as to flow vertically upward or downward through the passage. Disposed within the passage are heads (116) for introducing a liquid (118) into the passage such that the liquid (118) contacts the flue gases. A portion of the liquid (118) contacts the wall (114) of the tower (110), such that the portion of the liquid (118) flows downwardly along the wall (114). The tower (110) is equipped with a deflecting device (122) disposed on the wall (114) for deflecting the portion of the liquid (118) away from the wall (114), and thereafter reintroducing the portion of the liquid (118) into the passage so as to contact the gases flowing through the passage.

Abstract: A multilayer thermal barrier coating (TBC) having a low thermal conductivity that is maintained or even decreases as a result of a post-deposition high temperature exposure. The TBC comprises an inner layer and an insulating layer overlying the inner layer. The inner layer is preferably yttria-stabilized zirconia (YSZ), while the insulating layer contains barium strontium aluminosilicate (BSAS). After deposition, the TBC is heated to a temperature and for a duration sufficient to cause a decrease in the thermal conductivity of the BSAS-containing layer and, consequently, the entire TBC.

Abstract: An arc welding overlay apparatus that comprises a welding head carriage adapted for movement on a track, an index arm mounted for movement in a direction substantially transverse to the track, a slide mounted for movement in a direction substantially transverse to the index arm, a welding torch mounted to the slide, and means for dispensing a filler material to the welding torch. Feedback means and control means cooperate to indicate and control the movement of the weld head carriage, index arm, electric arc length and the filler dispensing rate. Means are also provided for emergency shutdown of the electric power source.

Abstract: An electron beam generator having circuit interconnections between individual components that are less prone to the adverse effects of thermal cycling. The generator includes a conductor rod within a guide tube, a center conductor secured to one end of the rod, and an outer conductor secured to the adjacent end of the guide tube. An opposite end of the center conductor has an integrally-formed flange extending radially therefrom. A first tower is secured and electrically connected to the flange, while a second and adjacent tower is electrically connected to the outer conductor. A filament is mounted to and between the first and second towers. A forward leg of the filament circuit comprises the conductor rod, the center conductor, the flange and the first tower, and the return leg of the filament circuit comprises the second tower and the guide tube interconnected by the outer conductor.

Abstract: A method of repairing a thermal barrier coating on a component designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method is particularly suited for completely removing a thermal insulating ceramic layer of thermal barrier coating system that includes a metallic bond coat, such as a diffusion aluminide or MCrAlY coating, between the surface of the component and the ceramic layer, while leaving the bond coat substantially undamaged. Furthermore, the method of this invention includes a technique by which ceramic material within cooling holes in the component can be removed without damaging the underlying bond coat. The process steps generally include removing the ceramic layer from the surface of the component by subjecting the ceramic layer to a caustic solution at an elevated temperature and pressure, and then removing ceramic material from the cooling hole by carefully directing a high-velocity fluid stream into the cooling hole.

Abstract: A thermal barrier coating (TBC) for a component intended for use in a hostile environment, such as the superalloy turbine, combustor and augmentor components of a gas turbine engine. The TBC is formed to contain small amounts of alumina precipitates dispersed throughout the grain boundaries and pores of the TBC to getter oxide impurities that would otherwise allow or promote grain sintering and coarsening and pore coarsening, the consequence of which would be densification of the TBC and therefore increased thermal conductivity. If sufficiently fine, the precipitates also serve to pin the grains and pore boundaries of the TBC, the effect of which is to reduce the tendency for the microstructure of the TBC to sinter, coarsen and undergo pore redistribution, which also increase thermal conductivity of the TBC 26.

Abstract: A heat exchanger manifold (10) and method of forming a tube port (50) on the manifold (10). The manifold (10) comprises first and second walls (12,14) that define an internal passage (18) and an outer cross-sectional shape of the manifold (10). The first wall (12) of the manifold (10) has a concave outer surface in which the tube port (50) of the manifold (10) is to be formed, while the second wall (14) has a convex outer surface. The tube port (50) is formed in the concave first wall (12), such as by piercing. The shapes of the first and second walls (12,14) promote the ability of the manifold (10) to resist deformation when forming the tube port (50) in the first wall (12).

Abstract: A pull-to-close collet chuck for use with lathes equipped with servo-type bar loaders. The chuck is configured to be coupled to a lathe drawtube and translates linear movement of the drawtube to a work-gripping action to a collet. The chuck generally includes a ramp body surrounding a first portion of the collet and integral means for fixing the ramp body within a central bore of the chuck. A piston surrounds the collet and has a bearing surface adjacent a ramp surface of the ramp body, and a wedge is located between the ramp surface of the ramp body and the bearing surface of the piston. The wedge has multiple bearing surfaces through which the work gripping action is transferred from the piston to the collet as a result of radial inward movement of the wedge.

Abstract: A braze material and method for repairing an article, such as a gas turbine engine combustor liner formed from a nickel-base or cobalt-base superalloy. The braze material is composed of a nickel-base braze alloy that is preferably in powder form and may be dispersed in a suitable vehicle to yield a slurry, putty or solid tape. The braze alloy is formulated to be capable of withstanding the high temperature operating environment of a combustor liner, and to have a melting temperature below the grain growth or incipient melting temperature of the superalloy to be repaired. A preferred braze alloy is formed by combining at least two nickel-base powders. A suitable composition for the braze alloy is, in weight percent, about 10 to about 19 chromium, about 3 to about 10.5 cobalt, about 1.75 to about 4.9 titanium, about 0.75 to about 3.4 aluminum, about 1.25 to about 4.1 tungsten, about 1.25 to about 4.1 molybdenum, about 0.025 to about 0.225 carbon, about 0.005 to about 0.15 zirconium, about 0.50 to about 2.

Abstract: A method for changing the surface termination of a perovskite substrate surface, an example of which is the conversion of B-site terminations of a single-crystal STO substrate to A-site terminations. The method generally comprises the steps of etching the substrate surface by applying a reactive plasma thereto in the presence of fluorine or another halogen, and then annealing the substrate at a temperature sufficient to regenerate a long range order of the surface, i.e., the surface termination contributes to a better long range order in a film epitaxially grown on the surface. More particularly, the resulting substrate surfaces predominantly contains A-site surface terminations, i.e., SrO for STO (100) substrates. As a result, disadvantages associated with B-site terminated perovskite substrate surfaces are avoided. A suitable etching treatment is a low power oxygen ashing in the presence of low halogen levels.

Abstract: A spout for a liquid container, such as a gasoline container, as well as a container equipped with the spout. The spout comprises a fluid passage and a vent passage fluidically parallel with the fluid passage. The fluid passage has an inlet, an outlet, and an S-shaped portion between the inlet and outlet. The vent passage has an inlet adjacent the outlet of the fluid passage. The S-shaped portion of the fluid passage is configured to entrap a liquid therein, causing a liquid lock to form, when a liquid is dispensed through the spout and air is prevented from flowing through the vent passage. In this manner, the spout is capable of preventing the overfilling of a receptacle tank being filled with fluid dispensed from a container equipped with the spout when the fluid level in the receptacle tank blocks the flow of air into the inlet of the vent passage.

Abstract: A device and method for maintaining the volume of a liquid contained within a cavity between two substrates to something equal or nearly equal to that of the volume of the cavity. A particular application is a liquid crystal display (LCD), in which a liquid crystal (LC) material is contained within a cavity between two flat display substrates. The device serves to minimize the volume differential between the liquid and the cavity caused by a change in temperature of the display, such that the formation of bubbles within the liquid is substantially or completely prevented. In so doing, the device essentially eliminates thermally-induced defects that would otherwise be visible to the user.

Abstract: A method for promoting the environmental resistance of nickel, iron and cobalt-base superalloys of the type alloyed to develop a protective oxide scale. The method entails a technique for removing sulfur during or subsequent to the casting operation. The method generally includes casting a superalloy article in a mold cavity, and then heat treating the article while surfaces of the article are in contact with a compound containing a sulfide and/or oxysulfide-forming element, such as yttria, calcium oxide, magnesia, scandia, ceria, hafnia, zirconia, titania, lanthana, alumina and/or silica. The heat treatment is performed at a temperature sufficient to cause sulfur within the superalloy article to segregate to the surfaces of the article and react with the sulfide-forming element, thereby forming sulfides at the interface with the compound.

Abstract: A thermal barrier coating (TBC) and method for forming the coating on a component intended for use in a hostile environment. The coating and method are particularly directed to inhibiting sintering, grain coarsening/growth and pore redistribution in the coating during high temperature excursions by providing limited amounts of extremely fine carbide-based and/or nitride-based precipitates preferably formed at defects and pores at and between the grain boundaries of the TBC microstructure. The precipitates pin the TBC grain boundaries and pores during high temperature excursions, with the effect that the TBC microstructure is thermally stabilized. A coating containing the carbides and/or nitrides can be formed using a physical vapor deposition technique in an atmosphere that contains carbon and/or nitride gases or compounds thereof, or by evaporating a source material that contains carbon, carbon-containing compounds, carbides and/or nitrides.

Abstract: A thermal barrier coating (TBC) system and method for forming the TBC system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The TBC system exhibits improved spallation resistance as a result of having a bond coat formed to contain a dispersion of oxide particles in its outer surface region. A method for preferentially entrapping oxide particles in a bond coat entails depositing the oxide particles on the surface of the component prior to forming the bond coat, which may be a diffusion aluminide or an aluminized overlay coating. Deposition of the bond coat causes the oxide particles to become dispersed in the outer surface region of the bond coat. A particular feature of this invention is the ability to preferentially entrap oxides of elements that are not present in the bond coat or a substrate region of the component on which the bond coat is formed.