Embodiments discloses herein relate to low-cost methods of producing a carbon foam through blending at least one carbon source with at least one solvent to form a mixture and heating the mixture at atmospheric pressure and in a non-oxidizing atmosphere to form a carbon foam. Given that the carbon foam is produced at atmospheric pressure, the methods disclosed herein may include a continuous process.

In one example, a method for forming a coating system including a bond coat and an environmental barrier coating on a ceramic or CMC substrate, e.g., with an abradable coating on the environmental barrier coating. The method may include depositing a bond coat on a ceramic or ceramic matrix composite (CMC) substrate to form an as-deposited bond coat; heat treating the as-deposited bond coat following the deposition of the as-deposited bond coat on the substrate to form a heat treated bond coat; depositing an environment barrier coating (EBC) layer on the heat treated bond coat to form as deposited EBC layer; and heat treating the as-deposited EBC layer to form a heat treated EBC layer.

In one example, a method for forming a coating system including a bond coat and an environmental barrier coating on a ceramic or CMC substrate, e.g., with an abradable coating on the environmental barrier coating. The method may include depositing a bond coat on a ceramic or ceramic matrix composite (CMC) substrate to form an as-deposited bond coat; heat treating the as-deposited bond coat following the deposition of the as-deposited bond coat on the substrate to form a heat treated bond coat; depositing an environment barrier coating (EBC) layer on the heat treated bond coat to form as deposited EBC layer; and heat treating the as-deposited EBC layer to form a heat treated EBC layer.

A method of applying a protective coating to a substrate includes the steps of: providing a turbine engine component substrate formed of a ceramic matrix composite material, forming an environmental barrier coating layer including a rare earth disilicate material directly on the substrate, treating an outer surface of the environmental barrier coating layer to form a thermal barrier coating layer including a porous rare earth monociliate material directly on the environmental barrier coating layer. The step of treating the outer surface is performed using a thermal process consisting of the application of heat or a chemical-thermal process consisting of the application of heat and a chemical. The method further includes infiltrating at least a portion of the pores with a metal solution or suspension.

A method of applying a protective coating to a substrate includes the steps of: providing a turbine engine component substrate formed of a ceramic matrix composite material, forming an environmental barrier coating layer including a rare earth disilicate material directly on the substrate, treating an outer surface of the environmental barrier coating layer to form a thermal barrier coating layer including a porous rare earth monociliate material directly on the environmental barrier coating layer. The step of treating the outer surface is performed using a thermal process consisting of the application of heat or a chemical-thermal process consisting of the application of heat and a chemical. The method further includes infiltrating at least a portion of the pores with a metal solution or suspension.

A process for manufacturing a porous abradable coating includes: filling a mold with hollow glass or thermosetting polymer beads and a slurry; and sintering heat treatment to obtain a ceramic layer with pores. A maximum sintering temperature of the green body of the ceramic part is either higher than the melting temperature of the hollow glass beads so that at the end of the sintering heat treatment the hollow glass beads are melted, or higher than the decomposition temperature of the hollow thermosetting polymer beads so that at the end of the sintering heat treatment the hollow thermosetting polymer beads are decomposed.

A method of producing a ceramic matrix composite including a protective ceramic coating thereon comprises applying a surface slurry onto an outer surface of an impregnated fiber preform. The surface slurry includes particulate ceramic solids dispersed in a flowable preceramic polymer comprising silicon, and the impregnated fiber preform comprises a framework of ceramic fibers loaded with particulate matter. The flowable preceramic polymer is cured, thereby forming on the outer surface a composite layer comprising a cured preceramic polymer with the particulate ceramic solids dispersed therein. The cured preceramic polymer is then pyrolyzed to form a porous ceramic layer comprising silicon carbide, and the impregnated fiber preform and the porous ceramic layer are infiltrated with a molten material comprising silicon. After infiltration, the molten material is cooled to form a ceramic matrix composite body with a protective ceramic coating thereon.

A method of producing a ceramic matrix composite including a protective ceramic coating thereon comprises applying a surface slurry onto an outer surface of an impregnated fiber preform. The surface slurry includes particulate ceramic solids dispersed in a flowable preceramic polymer comprising silicon, and the impregnated fiber preform comprises a framework of ceramic fibers loaded with particulate matter. The flowable preceramic polymer is cured, thereby forming on the outer surface a composite layer comprising a cured preceramic polymer with the particulate ceramic solids dispersed therein. The cured preceramic polymer is then pyrolyzed to form a porous ceramic layer comprising silicon carbide, and the impregnated fiber preform and the porous ceramic layer are infiltrated with a molten material comprising silicon. After infiltration, the molten material is cooled to form a ceramic matrix composite body with a protective ceramic coating thereon.

A coated article (20;60) includes a substrate (22) and a coating (24;62) on the substrate. The coating includes at least a first layer (30). The first layer has: a matrix (50); and a filler (52) at 2.0% to 40% by volume in the first layer. The first layer is selected from alkaline earth or transition metal (M) tungstates (MWO4); alkaline earth molybdates (MMoO.sub.4); rare earth (RE) phosphates (REPO.sub.4); and combinations thereof.

A coated article (20;60) includes a substrate (22) and a coating (24;62) on the substrate. The coating includes at least a first layer (30). The first layer has: a matrix (50); and a filler (52) at 2.0% to 40% by volume in the first layer. The first layer is selected from alkaline earth or transition metal (M) tungstates (MWO4); alkaline earth molybdates (MMoO.sub.4); rare earth (RE) phosphates (REPO.sub.4); and combinations thereof.