Abstract: In some examples, a method may include depositing, from a slurry comprising particles including silicon metal, a bond coat precursor layer including the particles comprising silicon metal directly on a ceramic matrix composite substrate. The method also may include locally heating the bond coat precursor layer to form a bond coat comprising silicon metal. Additionally, the method may include forming a protective coating on the bond coat. In some examples, an article may include a ceramic matrix composite substrate, a bond coat directly on the substrate, and a protective coating on the bond coat. The bond coat may include silicon metal and a metal comprising at least one of Zr, Y, Yb, Hf, Ti, Al, Cr, Mo, Nb, Ta, or a rare earth metal.

Abstract: In some examples, a method including forming a layer of a slurry composition between a first ceramic or CMC part and a second ceramic or CMC part. The slurry composition includes a carrier material; and a plurality of solid particles in the carrier material. The plurality of solid particles includes first silicon carbide (SiC) particles defining a first average particle size, second SiC particles defining a second average particles size that is less than the first average particles size, and reactive additive particles. The method includes heating the layer of slurry composition to react the plurality of reactive additive particles to fuse the plurality of first SiC particles and the plurality of second SiC particles together with the reactive additive particles, wherein the fused layer of the slurry composition forms a joint layer that joins the first ceramic or CMC part to the second ceramic or CMC part.

Abstract: In some examples, a method may include depositing, from a slurry comprising particles including silicon metal, a bond coat precursor layer including the particles comprising silicon metal directly on a ceramic matrix composite substrate. The method also may include locally heating the bond coat precursor layer to form a bond coat comprising silicon metal. Additionally, the method may include forming a protective coating on the bond coat. In some examples, an article may include a ceramic matrix composite substrate, a bond coat directly on the substrate, and a protective coating on the bond coat. The bond coat may include silicon metal and a metal comprising at least one of Zr, Y, Yb, Hf, Ti, Al, Cr, Mo, Nb, Ta, or a rare earth metal.

Abstract: In some examples, a method may include depositing, from a slurry comprising particles including silicon metal, a bond coat precursor layer including the particles comprising silicon metal directly on a ceramic matrix composite substrate. The method also may include locally heating the bond coat precursor layer to form a bond coat comprising silicon metal. Additionally, the method may include forming a protective coating on the bond coat. In some examples, an article may include a ceramic matrix composite substrate, a bond coat directly on the substrate, and a protective coating on the bond coat. The bond coat may include silicon metal and a metal comprising at least one of Zr, Y, Yb, Hf, Ti, Al, Cr, Mo, Nb, Ta, or a rare earth metal.

Abstract: A method of melt infiltrating a green ceramic matrix composite (CMC) article, wherein the green CMC article includes a ceramic reinforcing structure. The method includes heating a localized region of the green CMC article; melting a metal alloy infiltrant to form a molten metal alloy; and introducing the molten metal alloy into the localized region to infiltrate the reinforcing structure of the green CMC article with the metal alloy infiltrant and form the CMC article.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.

Abstract: A method of forming a composite article may include impregnating an inorganic fiber porous preform with a first slurry composition. The slurry composition includes particles, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to substantially immobilize the particles and yield a gelled article. The method also includes impregnating the gelled article with a second solution that includes a high char-yielding component, and pyrolyzing the high char-yielding component to yield carbon and form a green composite article. The green composite article is then infiltrated with a molten metal or alloy infiltrant to form the composite article. The molten infiltrant reacts with carbon, and the final composite article may include less residual metal or alloy than a composite article formed without using the second solution.

Abstract: A method for repairing a ceramic matrix composite (CMC) article including a ceramic material in a matrix including a metal alloy, wherein a localized region of the metal alloy has a defect. The method includes applying heat to the localized region for a time sufficient to increase the temperature of the metal alloy in the localized region above the melt temperature thereof and cause the metal alloy in the localized region to flow and seal the crack.

Abstract: A method of forming a composite article may include impregnating an inorganic fiber porous preform with a first slurry composition. The slurry composition includes particles, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to substantially immobilize the particles and yield a gelled article. The method also includes impregnating the gelled article with a second solution that includes a high char-yielding component, and pyrolyzing the high char-yielding component to yield carbon and form a green composite article. The green composite article is then infiltrated with a molten metal or alloy infiltrant to form the composite article. The molten infiltrant reacts with carbon, and the final composite article may include less residual metal or alloy than a composite article formed without using the second solution.

Abstract: A method of forming a composite article may include impregnating an inorganic fiber porous preform with a first slurry composition. The slurry composition includes particles, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to substantially immobilize the particles and yield a gelled article. The method also includes impregnating the gelled article with a second solution that includes a high char-yielding component, and pyrolyzing the high char-yielding component to yield carbon and form a green composite article. The green composite article is then infiltrated with a molten metal or alloy infiltrant to form the composite article. The molten infiltrant reacts with carbon, and the final composite article may include less residual metal or alloy than a composite article formed without using the second solution.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.

Abstract: In some examples, a method may include depositing, from a slurry comprising particles including silicon metal, a bond coat precursor layer including the particles comprising silicon metal directly on a ceramic matrix composite substrate. The method also may include locally heating the bond coat precursor layer to form a bond coat comprising silicon metal. Additionally, the method may include forming a protective coating on the bond coat. In some examples, an article may include a ceramic matrix composite substrate, a bond coat directly on the substrate, and a protective coating on the bond coat. The bond coat may include silicon metal and a metal comprising at least one of Zr, Y, Yb, Hf, Ti, Al, Cr, Mo, Nb, Ta, or a rare earth metal.

Abstract: A method of forming a composite article may include impregnating an inorganic fiber porous preform with a first slurry composition. The slurry composition includes particles, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to substantially immobilize the particles and yield a gelled article. The method also includes impregnating the gelled article with a second solution that includes a high char-yielding component, and pyrolyzing the high char-yielding component to yield carbon and form a green composite article. The green composite article is then infiltrated with a molten metal or alloy infiltrant to form the composite article. The molten infiltrant reacts with carbon, and the final composite article may include less residual metal or alloy than a composite article formed without using the second solution.

Abstract: A method for repairing a ceramic matrix composite (CMC) article including a ceramic material in a matrix including a metal alloy, wherein a localized region of the metal alloy has a defect. The method includes applying heat to the localized region for a time sufficient to increase the temperature of the metal alloy in the localized region above the melt temperature thereof and cause the metal alloy in the localized region to flow and seal the crack.

Abstract: A method of melt infiltrating a green ceramic matrix composite (CMC) article, wherein the green CMC article includes a ceramic reinforcing structure. The method includes heating a localized region of the green CMC article; melting a metal alloy infiltrant to form a molten metal alloy; and introducing the molten metal alloy into the localized region to infiltrate the reinforcing structure of the green CMC article with the metal alloy infiltrant and form the CMC article.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.