Abstract: Silicon carbide ceramic matrix composites, and hybrid ceramic materials are provided. In one embodiment, the silicon carbide composites comprise reinforcement material further comprising a simplified coating, and in others, the composites comprise uncoated reinforcement material. The hybrid ceramic materials comprise at least two of a conventional ceramic matrix composite, a monolithic ceramic, the composite comprising uncoated reinforcement material, and the composite comprising reinforcement material comprising a simplified coating. Methods of providing the composites are also provided.

Abstract: An article for use in aggressive environments is presented. In one embodiment, the article comprises a substrate and a self-sealing and substantially hermetic sealing layer disposed over the bondcoat. The substrate may be any high-temperature material, including, for instance, silicon-bearing ceramics and ceramic matrix composites. A method for making such articles is also presented. The method comprises providing a substrate; disposing a self-sealing layer over the substrate; and heating the sealing layer to a sealing temperature at which at least a portion of the sealing layer will flow.

Abstract: A treated refractory material includes a sintered porous refractory material having one or more protective materials disposed within pores of the refractory material, wherein the protective material is selected from the group consisting of aluminum oxide, chromium oxide, silica, rare earth oxides, rare earth zirconates, titanium oxide, mullite, zirconium oxide, zirconium silicate, yttrium oxide, magnesium oxide, iron oxide, and blends thereof. Methods of preparing the treated refractory material are also provided. The treated refractory material provides protection from the penetration of slag and extends the service life of the refractory.

Abstract: An article comprises a substrate and a coating disposed over the substrate, wherein the coating comprises a monoclinic silicate phase that undergoes no solid state phase transformation reaction in the temperature range from about 1100 degrees Celsius to about 1275 degrees Celsius.

Abstract: A process and apparatus for continuously depositing a coating on a fibrous material. The process is a chemical vapor deposition process that includes causing multiple strands of a fibrous material to continuously travel through a coating zone within an enclosed chamber defined by a housing so that portions of the strands contact a reactant gas as the portions travel through the chamber, directly heating the portions of the strands without physically contacting the strands and without directly heating the housing, and depositing a coating material on the strands as a result of the reactant gas contacting the portions of the strands and decomposing to form a coating of the coating material. Heating of the strands can be achieved by capacitive coupling, inductive coupling, microwave radiation, and radiant heating.

Abstract: An article for use in aggressive environments is presented. In one embodiment, the article comprises a substrate and a self-sealing and substantially hermetic sealing layer disposed over the bondcoat. The substrate may be any high-temperature material, including, for instance, silicon-bearing ceramics and ceramic matrix composites. A method for making such articles is also presented. The method comprises providing a substrate; disposing a self-sealing layer over the substrate; and heating the sealing layer to a sealing temperature at which at least a portion of the sealing layer will flow.

Abstract: An article for use at high temperature, such as a component for a gas turbine assembly, is presented. The article comprises a substrate comprising silicon; a bondcoat disposed over the substrate, wherein the bondcoat comprises a silicide of a platinum-group metal; and a topcoat disposed over the bondcoat, wherein the topcoat comprises a ceramic material.

Abstract: A method for fabricating a component having an environmental barrier coating. The method includes providing a component including silicon having a first coefficient of thermal expansion. A bondcoat is bonded to at least a portion of an outer surface of the component. An intermediate layer having a general composition of RE2Si2O7 is bonded to the bondcoat. The intermediate layer has a second coefficient of thermal expansion matched to the first coefficient of thermal expansion. A protective layer having a general composition of RE2SiO5 is bonded to the intermediate layer. A surface layer is bonded to the protective layer. The surface layer includes RE and has a ratio of RE to oxygen of at least 2:3.

Abstract: An article for use in aggressive environments is presented. In one embodiment, the article comprises a substrate and a self-sealing and substantially hermetic sealing layer comprising an alkaline-earth aluminosilicate disposed over the bondcoat. The substrate may be any high-temperature material, including, for instance, silicon-bearing ceramics and ceramic matrix composites. A method for making such articles is also presented. The method comprises providing a substrate; disposing a self-sealing alkaline-earth aluminosilicate layer over the substrate; and heating the sealing layer to a sealing temperature at which at least a portion of the sealing layer will flow.

Abstract: An article for use in aggressive environments is presented. In one embodiment, the article comprises a substrate and a self-sealing and substantially hermetic sealing layer disposed over the bondcoat. The substrate may be any high-temperature material, including, for instance, silicon-bearing ceramics and ceramic matrix composites. A method for making such articles is also presented. The method comprises providing a substrate; disposing a self-sealing layer over the substrate; and heating the sealing layer to a sealing temperature at which at least a portion of the sealing layer will flow.

Abstract: A method of operating a gas turbine that utilizes vanadium-containing fuels at a combustion stage of the turbine thereby producing a combustion product having vanadium gaseous species, the method comprising increasing the volatility of the vanadium gaseous species in the combustion product atmosphere generated in a combustor of the turbine by increasing concentration of water vapor in the combustion product.

Abstract: A method for fabricating a component having an environmental barrier coating. The method includes providing a component including silicon having a first coefficient of thermal expansion. A bondcoat is bonded to at least a portion of an outer surface of the component. An intermediate layer having a general composition of RE2Si2O7 is bonded to the bondcoat. The intermediate layer has a second coefficient of thermal expansion matched to the first coefficient of thermal expansion. A protective layer having a general composition of RE2SiO5 is bonded to the intermediate layer. A surface layer is bonded to the protective layer. The surface layer includes RE and has a ratio of RE to oxygen of at least 2:3.

Abstract: An environmental barrier coating for a component including silicon that has a first coefficient of thermal expansion is provided. The environmental coating includes a silicon bondcoat that is bonded to at least a portion of an outer surface of the component. An intermediate layer is bonded to the silicon bondcoat and has a second coefficient of thermal expansion matched to the first coefficient of thermal expansion. The intermediate layer has a general composition of RE2Si2O7. A protective layer is bonded to the intermediate layer and has a general composition of RE2SiO5. A surface layer is bonded to the protective layer. The surface layer includes RE and has a ratio of RE to oxygen of at least 2:3.

Abstract: An environmental barrier coating for a component including silicon that has a first coefficient of thermal expansion is provided. The environmental coating includes a silicon bondcoat that is bonded to at least a portion of an outer surface of the component. An intermediate layer is bonded to the silicon bondcoat and has a second coefficient of thermal expansion matched to the first coefficient of thermal expansion. The intermediate layer has a general composition of RE2Si2O7. A protective layer is bonded to the intermediate layer and has a general composition of RE2SiO5. A surface layer is bonded to the protective layer. The surface layer includes RE and has a ratio of RE to oxygen of at least 2:3.

Abstract: An article resistant to recession in high temperature environments, and methods for making the article, are presented herein. The article comprises a substrate, an intermediate coating system disposed over the substrate, and a topcoat disposed over the intermediate coating system. The intermediate coating system comprises a separator layer comprising an oxygen getter material, and a barrier layer disposed over the separator layer, the barrier layer comprising a ceramic composition. The topcoat also comprises this ceramic composition. Moreover, at least about 50% by volume of the ceramic composition present in the barrier layer is a metastable precursor material that tends to transform over time into a product material. At least about 75% by volume of the ceramic composition present in the topcoat is the product material, and up to about 25% by volume of the ceramic composition present in the topcoat is the metastable precursor material.

Abstract: An article for use in aggressive environments is presented. In one embodiment, the article comprises a substrate and a self-sealing and substantially hermetic sealing layer disposed over the bondcoat. The substrate may be any high-temperature material, including, for instance, silicon-bearing ceramics and ceramic matrix composites. A method for making such articles is also presented. The method comprises providing a substrate; disposing a self-sealing layer over the substrate; and heating the sealing layer to a sealing temperature at which at least a portion of the sealing layer will flow.

Abstract: A treated refractory material includes a sintered porous refractory material having one or more protective materials disposed within pores of the refractory material, wherein the protective material is selected from the group consisting of aluminum oxide, chromium oxide, silica, rare earth oxides, rare earth zirconates, titanium oxide, mullite, zirconium oxide, zirconium silicate, yttrium oxide, magnesium oxide, iron oxide, and blends thereof. Methods of preparing the treated refractory material are also provided. The treated refractory material provides protection from the penetration of slag and extends the service life of the refractory.

Abstract: In a method of coating a CMC fiber, a multiplicity of fiber tows aligned as a ribbon are simultaneously passed through a reactor and a flow of fiber coating reactant is passed though the reactor to coat the tow fibers. A coating system comprises a reactor chamber to accommodate a multiplicity of fiber tows passing along a path substantially parallel to a longitudinal axis of the chamber and a flow of fiber coating reactant and an aligning structure at an end of the chamber to maintain the multiplicity of fiber tows in a narrow, elongated ribbon configuration. An article comprises a multiplicity of fiber tows aligned in a longitudinal planar array in the form of a ribbon.

Abstract: A material and an article comprising the material are presented. The material comprises a plurality of structural components. The structural components are configured in a series of increasing structural component size classes. The series has a base unit size class and at least one modular size class, and a component of the at least one modular size class comprises a plurality of components of the next smaller size class in the series. The structural components of the base unit size class comprise at least one bulk phase, and the structural components are bonded together at interfaces. Mechanical damage originating within a modular size class structural component is energetically favored to propagate in a distributed fashion among the plurality of structural components contained within the modular size class structural component.

Abstract: A coating for silicon based materials such as those used in high temperature, aqueous environments. An aspect of the invention is directed to an article including a silicon based substrate, a bond coat comprising silicon, and a barrier coat. The barrier coat includes an aluminate such as an alkaline earth metal aluminate or a rare earth aluminate. The barrier coat may be an intermediate coat between the bond coat and a top coat, or it may be the top coat.