The present disclosure provides a method for coating a composite structure, comprising forming a first slurry by combining a first pre-slurry composition with a first carrier fluid, applying the first slurry on a surface of the composite structure, and heating the composite structure to a temperature sufficient to form a base layer on the composite structure. The first pre-slurry composition may comprise a first phosphate glass composition and a low coefficient of thermal expansion material, wherein the low coefficient of thermal expansion material is a material with a coefficient of thermal expansion of less than 10×10.sup.−6° C..sup.−1.

The present disclosure provides a method for coating a composite structure, comprising forming a first slurry by combining a first pre-slurry composition with a first carrier fluid, applying the first slurry on a surface of the composite structure, and heating the composite structure to a temperature sufficient to form a base layer on the composite structure. The first pre-slurry composition may comprise a first phosphate glass composition and a low coefficient of thermal expansion material, wherein the low coefficient of thermal expansion material is a material with a coefficient of thermal expansion of less than 10×10.sup.−6° C..sup.−1.

The present disclosure provides a method for coating a composite structure, comprising applying a first slurry on a surface of the composite structure, heating the composite structure to a temperature sufficient to form a base layer on the composite structure, forming a sealing slurry comprising at least one of acid aluminum phosphate or orthophosphoric acid, applying the sealing slurry to the base layer, and heating the composite structure to a second temperature sufficient to form a sealing layer on the base layer.

The present disclosure provides a method for coating a composite structure, comprising applying a first slurry on a surface of the composite structure, heating the composite structure to a temperature sufficient to form a base layer on the composite structure, forming a sealing slurry comprising at least one of acid aluminum phosphate or orthophosphoric acid, applying the sealing slurry to the base layer, and heating the composite structure to a second temperature sufficient to form a sealing layer on the base layer.

Hybrid composite materials including carbon nanotube sheets and flexible ceramic materials, and methods of making the same are provided herein. In one embodiment, a method of forming a hybrid composite material is provided, the method including: placing a layer of a first flexible ceramic composite on a lay-up tooling surface; applying a sheet of a pre-preg carbon fiber reinforced polymer on the flexible ceramic composite; curing the flexible ceramic composite and the pre-preg carbon fiber reinforced polymer sheet together to form a hybrid composite material; and removing the hybrid composite material from the lay-up tooling surface, wherein the first flexible ceramic composite comprises an exterior surface of the hybrid composite material.

Inventive manufacture of CrB.sub.2—Al.sub.2O.sub.3 composites is based on pressureless sintering. According to typical inventive practice, CrB.sub.2 powder and Al.sub.2O.sub.3 powder are mixed together in selected volumetric proportions so that the volume of the CrB.sub.2 does not exceed 50% of the overall volume of the CrB.sub.2—Al.sub.2O.sub.3 mixture. The CrB.sub.2—Al.sub.2O.sub.3 mixture is shaped into a green body. The green body is pressureless sintered in a non-oxidizing atmosphere at a firing temperature in the approximate range between 1600° C. and 2050° C. The present invention succeeds in preparing, via pressureless sintering, a proportionality-associated range of compositions in the CrB.sub.2—Al.sub.2O.sub.3 system, which is a potentially “advanced” ceramic system. A typical inventively fabricated CrB.sub.2—Al.sub.2O.sub.3 composite is inventively configured in a complex shape, and has “advanced” material (e.g., mechanical) properties that are favorable for a contemplated application. Inventive manufacture of ceramic-ceramic composites is thus dually attributed, and uncommonly so, with complex shape-ability and advanced capability.

A method is provided in which a resin coating is applied to a surface of a preform. The resin coating includes a carbonaceous resin and a particulate. The preform is added to a tooling. The preform, which is positioned in the tooling, is cured. The tooling is removed. The resin coating on the surface of the preform is pyrolyzed to form a resin carbon-char layer on the surface of the preform. The preform and the resin carbon-char layer are infiltrated with silicon to form a ceramic matrix composite (CMC) component including a layer of silicon carbide. During the infiltration, the silicon reacts with carbon in the resin carbon-char layer to form the layer of silicon carbide on the preform.

A method is provided in which a resin coating is applied to a surface of a preform. The resin coating includes a carbonaceous resin and a particulate. The preform is added to a tooling. The preform, which is positioned in the tooling, is cured. The tooling is removed. The resin coating on the surface of the preform is pyrolyzed to form a resin carbon-char layer on the surface of the preform. The preform and the resin carbon-char layer are infiltrated with silicon to form a ceramic matrix composite (CMC) component including a layer of silicon carbide. During the infiltration, the silicon reacts with carbon in the resin carbon-char layer to form the layer of silicon carbide on the preform.

Thin films of precious metals such as platinum and gold have the required ability to withstand high temperatures, but in pure form can suffer from grain growth, agglomeration and dewetting at high temperature. Grain boundaries must therefore be pinned by alloying with other metals and/or by inclusion of non-metallic nanoparticles. While such bulk materials are known in the prior art, they have not existed previously as printable inks that can be deposited by additive manufacturing direct-write methods. These materials have been formulated for the first time as alloy and composite inks so that they may be applied by direct-write additive manufacturing techniques directly onto three-dimensional components or on high temperature substrates that can be adhered to complex components.

Thin films of precious metals such as platinum and gold have the required ability to withstand high temperatures, but in pure form can suffer from grain growth, agglomeration and dewetting at high temperature. Grain boundaries must therefore be pinned by alloying with other metals and/or by inclusion of non-metallic nanoparticles. While such bulk materials are known in the prior art, they have not existed previously as printable inks that can be deposited by additive manufacturing direct-write methods. These materials have been formulated for the first time as alloy and composite inks so that they may be applied by direct-write additive manufacturing techniques directly onto three-dimensional components or on high temperature substrates that can be adhered to complex components.