Abstract: A chemical vapor deposition (CVD) reactor includes a double wall vacuum processing chamber with an inner wall and an outer wall and fluid passages between the walls. A layer of thermal insulation covers the outer wall. A layer of high temperature thermal insulation covers the inner wall. Heating elements are positioned in the interior of the processing chamber to heat a substrate mounted in the chamber. A gas inlet structure is positioned through the inner and outer walls of the chamber and oriented to direct a flow of reactant gas against the substrate to form a CVD coating on the substrate. A gas outlet structure connected to a vacuum and effluent management system is positioned through the inner and outer walls of the chamber.

Abstract: A ceramic composite article includes ceramic reinforcement fibers each having an outer surface and a continuous zinc oxide coating disposed on the ceramic reinforcement fibers and in contact with the outer surfaces.

Abstract: A method for desulfurizing a metal alloy comprises heating the metal alloy to a molten state. A gaseous desulfurizing compound is bubbled through the molten alloy to form a solid sulfur-containing waste phase and a molten reduced-sulfur alloy phase. The solid waste phase and the molten reduced-sulfur alloy phase are separated. The gaseous desulfurizing compound includes a constituent element selected from the group: alkali metals, alkaline earth metals, and rare earth metals.

Abstract: A method to form a ceramic interface coating on ceramic matrix composite (CMC) precursor tape by a continuous process includes passing a ceramic fiber woven cloth tape or unidirectional tape of a first ceramic with a first and second surface through at least one reaction zone of a continuous vacuum chemical vapor deposition (CVD) or chemical vapor infiltration (CVI) reactor heated to a reaction temperature. The method further includes directing a flow of CVD or CVI reactant gas of a second ceramic at the first surface of the tape in a direction perpendicular to the tape such that the reactant gas passes through the tape in a forced flow process depositing the second ceramic on the fibers of the first ceramic thereby coating the fibers of the first ceramic tape with the second ceramic to interface coating form a coated fiber CMC precursor tape product.

Abstract: A chemical vapor deposition (CVD) reactor includes a double wall vacuum processing chamber with an inner wall and an outer wall and fluid passages between the walls. A layer of thermal insulation covers the outer wall. A layer of high temperature thermal insulation covers the inner wall. Heating elements are positioned in the interior of the processing chamber to heat a substrate mounted in the chamber. A gas inlet structure is positioned through the inner and outer walls of the chamber and oriented to direct a flow of reactant gas against the substrate to form a CVD coating on the substrate. A gas outlet structure connected to a vacuum and effluent management system is positioned through the inner and outer walls of the chamber.

Abstract: A casting system includes a core and a shell positioned relative to the core. A barrier coating is applied on at least one of the core and the shell, and may be applied to both the core and the shell. The barrier coating limits reaction between the casting system and a casting alloy.

Abstract: A ceramic composite article includes ceramic carbide fibers and a ceramic matrix in which the ceramic carbide fibers are embedded. The ceramic matrix includes a laminar structure with at least one layer of a first ceramic material and at least one layer of a second, different ceramic material.

Abstract: A method for desulfurizing a metal alloy comprises heating the metal alloy to a molten state. A gaseous desulfurizing compound is bubbled through the molten alloy to form a solid sulfur-containing waste phase and a molten reduced-sulfur alloy phase. The solid waste phase and the molten reduced-sulfur alloy phase are separated. The gaseous desulfurizing compound includes a constituent element selected from the group: alkali metals, alkaline earth metals, and rare earth metals.

Abstract: A ceramic composite article includes ceramic carbide fibers and a ceramic matrix in which the ceramic carbide fibers are embedded. The ceramic matrix includes a laminar structure with at least one layer of a first ceramic material and at least one layer of a second, different ceramic material.

Abstract: A ceramic composite article includes ceramic reinforcement fibers each having an outer surface and a continuous zinc oxide coating disposed on the ceramic reinforcement fibers and in contact with the outer surfaces.

Abstract: A method of forming a highly densified chemical matrix composite CMC from a preform of a matrix of a non-oxide ceramic and continuous ceramic fibers. An interface coating is added, followed by partially densifying the preform with a resin to increase the density of the preform using a polymer infiltration pyrolysis PIP) process one or more times. A chemical vapor infiltration (CVI) process is used to bring the CMC to a final desired density.

Abstract: A ceramic matrix composite is formed from a non-oxide ceramic and continuous ceramic fibers. The matrix includes a hafnium donor in the matrix in an amount sufficient to harden the composite at elevated temperatures to prevent ablation of the composite. The matrix also includes a boron donor in the matrix in an amount sufficient to lower the glass transition temperature of the composite to flow over cracks formed in the composite. The method to form the matrix is selected from polymer infiltration pyrolysis, chemical vapor infiltration, and sequential polymer infiltration pyrolysis and chemical vapor infiltration.

Abstract: A casting system includes a core and a shell positioned relative to the core. A barrier coating is applied on at least one of the core and the shell.

Abstract: In a method for coating a molybdenum-based substrate, a molybdenum disilicide layer is formed on the substrate. Aluminum is reacted with hydrochloric gas to produce aluminum chloride. The aluminum chloride is reacted with hydrogen and carbon dioxide to produce alumina. A layer of the alumina is deposited atop the molybdenum disilicide layer.