Methods for fabricating ceramic matrix composites (CMCS)

Abstract

A method for fabricating a melt-infiltrated ceramic matrix composite, comprising the steps of providing a ceramic preform comprising at least one fiber, fiber bundle, or fiber tow; optionally depositing an interface coating on the fiber, fiber bundle or fiber tow; fabricating a structure comprising a carbon-containing coating within the ceramic preform; infiltrating at least one molten metal, one molten metalloid, molten metal alloy, or molten metalloid alloy, within the ceramic preform and in contact with the structure; and reacting the molten metal, molten metalloid, molten metal alloy, or molten metalloid alloy, with the carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

Description

METHODS FOR FABRICATINGCERAMIC MATRIX COMPOSITES (CMCs)CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Patent Application No. 63 / 665,214 filed on June 27, 2024, which is hereby incorporated by reference for all purposes as if fully set forth herein.FIELD OF THE INVENTION

[0002] The subject matter disclosed herein relates to methods for fabricating ceramic matrix composites (CMCs) and, in particular, to methods for distributing material within melt infiltrated (Ml) CMCs using an internal structure.BACKGROUND OF THE INVENTION

[0003] Producing CMCs can include first impregnating a chemical vapor infiltrated (CVI) CMC preform with a carbon source. Afterwards, the impregnated CMC preform is infiltrated with an alloy in a molten state that reacts with the carbon source. Generally, the resultant reaction forms a carbide-containing matrix within the CMC preform. The carbon source can include a slurry containing carbon-based particles or a hydrocarbon-based resin. Challenges with this process include initially loading a sufficient amount of carbon in the slurry, uniformly distributing the carbon within the CMC preform, and producing the desired quantity of reaction-formed carbide(s) with the CMC preform.

[0004] With respect to loading and uniform distribution, if the slurry contains too many carbonbased particles and / or too much hydrocarbon-based resin, the particles and / or resin will begin clustering. Those same particles and / or resin also will impregnate a CMC preform as a cluster. For example, the clustered impregnated particles and / or resin will accumulate within certain areas and not distribute throughout the entire CMC preform. Such clustering may block a pore area between fibers of the CMC preform. In turn, additional particles and / or resin cannot further impregnate the CMC preform. Moreover, the viscosity of the slurry also can increase too highfor the particles and / or resin to impregnate the CMC preform. In turn, the amount of carbon initially loaded in the slurry is decreased due to the aforementioned clustering effect and particle and / or resin slurry loading limitations. With respect to uniform distribution, once the impregnated CMC preform is dried, the clustered particles and / or resin becomes non-uniformly distributed within the CMC preform and, in turn, the resultant Ml CMC. As a consequence, the resultant Ml CMC matrix contains non-uniformly distributed materials such as, but not limited to, carbides, silicides, residual free silicon, metals, alloys thereof, combinations comprising at least one of the foregoing, and the like. These non-uniformly distributed materials can result in high internal stresses due to a coefficient of thermal expansion (CTE) mismatch between the aforementioned materials. The non-uniformly distributed materials can also lead to other properties to be non-uniform throughout the resultant CMC material, e.g., thermal conductivity, and again lead to an inferior or defective resultant CMC material.SUMMARY OF THE INVENTION

[0005] According to an embodiment of the present disclosure, there is provided a method for fabricating a melt-infiltrated ceramic matrix composite, comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform; infiltrating at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, within the ceramic preform and in contact with the structure; andreacting at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, with the at least one carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

[0006] According to another embodiment of the present disclosure, there is provided a melt- infiltrated ceramic matrix composite produced by a process comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform; infiltrating at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, within the ceramic preform and in contact with the structure; and reacting at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, with the at least one carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

[0007] According to yet another embodiment of the present disclosure, there is provided a ceramic preform comprising a structure produced by a process comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing;optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; and fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform.

[0008] According to still yet another embodiment of the present disclosure, there is provided a gas turbine engine component comprising a melt-infiltrated ceramic matrix composite produced by a process comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform; infiltrating at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, within the ceramic preform and in contact with the structure; and reacting at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, with the at least one carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

[0009] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at leastone carbon-containing coating within the at least one ceramic preform further comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0010] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; andinfiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

[0011] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0012] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the structure comprising the carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the ceramic preform.

[0013] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, wherein the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0014] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material;sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; and infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

[0015] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0016] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the structure comprising the carbon-containing coatingcomprises carbon present in an amount of approximately 0.1 volume percent to approximately70 volume percent based on the total volume of the ceramic preform.

[0017] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0018] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material;freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; and infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

[0019] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0020] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the structure comprising the carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the ceramic preform.

[0021] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0022] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material;freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; and infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

[0023] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the step of fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform further comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

[0024] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the structure comprising the carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the ceramic preform.BRIEF DESCRIPTION OF FIGURES

[0025] The features of the disclosure believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The disclosure itself, however, both as to organization and method of operation, can best be understood by reference to the description of the preferred embodiment(s) which follows, taken in conjunction with the accompanying drawings in which:

[0026] Figure 1 is a flowchart illustrating at least one exemplary method for fabricating a Ml CMC.

[0027] Figure 2 is a flowchart illustrating at least one possible exemplary step of the method of Figure 1.

[0028] Figure 3 is a flowchart illustrating at least one other possible exemplary step of the method of Figure 1.

[0029] Figure 4 is a flowchart illustrating at least yet another possible exemplary step of the method of Figure 1.

[0030] Figure 5 is an illustration of an exemplary CMC preform containing fiber bundles encapsulated within an exemplary freeze-dried foam-like structure of the original binder material.

[0031] Figure 6 is an illustration of the exemplary CMC preform of Figure 5 whose exemplary frozen foam-like structure is coated with chemical vapor infiltrated carbon.

[0032] Figure 7 is an illustration of the exemplary Ml CMC of the CMC preform of Figure 6 after undergoing melt-infiltration and conversion of the CVI carbon-coating of the exemplary frozen foam-like structure into a carbide-containing matrix material encapsulating the fiber bundles.

[0033] Figure 8 is an illustration of an exemplary CMC preform containing fiber bundles encapsulated within an exemplary freeze-dried particulate material structure.

[0034] Figure 9 is an illustration of the exemplary CMC preform of Figure 8 whose exemplary frozen particulate material structure is coated with chemical vapor infiltrated carbon.

[0035] Figure 10 is an illustration of an exemplary Ml CMC of the CMC preform of Figure 9 after undergoing melt-infiltration and conversion of the CVI carbon-coating of the exemplary frozen particulate material structure into a carbide-containing matrix material encapsulating the fiber bundles.

[0036] Figure 11 is a microphotograph of an exemplary CMC preform containing an exemplary frozen foam-like structure coated with chemical vapor infiltrated carbon encapsulating the fiber bundles.DETAILED DESCRIPTION OF THE INVENTION

[0037] The embodiments of the present disclosure can comprise, consist of, and consist essentially of the features and / or steps described herein, as well as any of the additional or optional ingredients, components, steps, or limitations described herein or would otherwise be appreciated by one of skill in the art. It is to be understood that all concentrations disclosed herein are by weight percent (wt. %.) based on a total weight of the composition unless otherwise indicated.

[0038] By improving an internal structure within a CMC preform, a larger volume of carbon may be impregnated into and uniformly distributed within the CMC preform. To sufficiently impregnate a larger volume of carbon within the CMC preform an infrastructure serving as astructure for the deposition of a larger volume of carbon may be installed therein. For example, a structure may be fabricated and installed in situ within the interstitial spaces or voids present between the fibers and / or fiber tows of the CMC preform. As a result, the larger impregnated carbon volume leads to an increased carbide presence in the resultant Ml CMC. The resultant Ml CMC exhibits and possesses very desirable high temperature properties due to the increased carbide presence. Thus, achieving both a higher carbon loading on the structure and, in turn, a more uniform carbon distribution throughout the CMC preform are desirable outcomes.

[0039] The present disclosure is directed to at least one exemplary method for fabricating an exemplary Ml CMC containing such an exemplary structure. Referring now to Figure 1, a flowchart 100 illustrates at least one such exemplary method. At an exemplary step 200, an exemplary ceramic preform is provided. In an at least one alternative embodiment, at an optional step 250, an interface material may be deposited on and around the exterior surface of at least one fiber and / or fiber tow of the CMC preform to form at least one interface coating (IFC), and form an IFC ceramic perform containing a plurality of IFC fiber tows. The IFC may exhibit and possess an exemplary thickness of between about 5 nm and about 50 pm. Deposition may take place using a technique, such as but not limited to, chemical vapor infiltration (CVI), chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), molecular-beam epitaxy, combinations comprising any one of the foregoing, and the like. The IFC materials may be any materials suitable for providing desired adhesion properties and compatibility between SiC and material of the fibers and / or fiber tows. Suitable IFC materials may include, but are not limited to, boron nitride (BN), carbon (C), Si-doped BN, silicon nitride (Si3N4), silicon carbon nitride (SiCN), silicon carbide (SiC), boron carbide (B4C), combinations comprising any one of the foregoing, and the like.

[0040] Next, at an exemplary step 300, an exemplary structure can be fabricated within the ceramic preform and, in particular, around and between the fibers and / or fiber tows contained therein. When fabricating the exemplary structure, at least one exemplary fabrication step may be employed as will be discussed below.

[0041] Referring to Figures 1, 2 and 5-7, at a first possible exemplary fabrication step 310, an exemplary structure may be fabricated within the ceramic preform using a freeze-drying technique. For example, at an exemplary step 312, the ceramic preform may be infiltrated with a slurry containing a binder material (See Figure 2). Slurry additives, e.g., dispersant, wetting agent, pH adjustors, surfactants, defoamers, ice crystal modifiers, ice nucleators, and the like, may be used to enhance the properties of the slurry. The binder materials contemplated herein may include any materials capable of forming a foam-like material when subjected to freeze-drying conditions and, in turn, forming the resultant structure. Suitable binder materials may include, but are not limited to, polyvinyl alcohol, polyvinyl butyral, methyl cellulose, carbo-ethyl cellulose, hydroxypropyl methyl cellulose, gellan gum, gelatin, pectin, aragose gum, konjac gum, carrageenan gum, alginate, sodium alginate, agar gum, non-ionic copolymer surfactant, e.g., Pluronic® F-127, commercially available from Sigma-Aldrich, Inc., St. Louis, Missouri; combinations comprising any one of the foregoing, and the like. The infiltration technique may be any technique capable of filling the interstitial spaces or volumes within the ceramic preform and, in particular, around and between the fibers and / or fibers tows contained therein. Suitable infiltration techniques may include, but are not limited to, any technique capable of infiltrating a slurry, and its contents, within and throughout the entirety of the preform. For example, suitable infiltration techniques may comprise a vacuum infiltration and / or pressure infiltration. At an exemplary step 314, after infiltration occurs, the exemplary infiltrated ceramic preform may undergo a freeze-drying technique (See Figure 2). The freeze-drying technique may be any technique capable of controlling the transformation of the binder material into a freeze-dried, foam-like binder material, also known as the resultant exemplary structure. Suitable freeze- drying techniques may include, but are not limited to, any technique capable of freezing the slurry, and its constituents, within and throughout the entirety of the preform. Next, at an exemplary step 316, the solvent of the frozen slurry infiltrated preform may be sublimated. Suitable sublimation techniques may include, but are not limited to, any technique capable of converting the solvent of the frozen slurry from a solid phase to a gaseous phase.

[0042] It has been discovered that when the preform containing a binder is freeze dried, the binder forms a "foam-like" material. The resulting foam-like material uniformly fills the voids between the fibers, fiber tows and / or fiber bundles, see figure 5 and figure 11. If using heat to evaporate the solvent, the binder can form a coating on the surface of the fibers, fiber tows and / or fiber bundles instead of forming a foam-like structure in between the voids of the fibers, fiber tows and / or fiber bundles. As a result, the binder does not fill the voids between the fibers, fiber tows and / or fiber bundles and does not provide an adequate foam-like structure. By using a freeze-drying technique, the foam-like structure within the infiltrated fiber preform may be controlled, thereby also controlling the pore size and shape, within the fiber preform. Upon freeze-drying, the exemplary foam-like binder material, i.e., resultant exemplary structure, may be fabricated. As illustrated in Figure 5, the resultant exemplary CMC preform 1000 contains fiber bundles 1100 encapsulated within an exemplary frozen foam-like structure of the original binder material 1200.

[0043] Next, at an exemplary step 318, the exemplary ceramic preforms containing the structure may be vapor infiltrated with a gaseous carbon source (See Figure 2). The carbon source may be any gaseous carbon material capable depositing carbon onto the freeze-dried, foam-like structure. Suitable gaseous carbon sources may include, but are not limited to, methane, propane, combinations comprising at least one of the foregoing, and the like. The infiltration technique may be any technique capable of filling the interstitial spaces or volumes within the ceramic preform and, in particular, around and / or between the fibers, fiber bundles and / or fibers tows contained therein. Generally, such an infiltration technique may include, but are not limited to, chemical vapor infiltration (CVI) techniques. Suitable CVI techniques may include, but are not limited to, isothermal CVI, thermal gradient CVI, pressure gradient CVI, low pressure CVI, microwave CVI, combinations comprising at least one of the foregoing, and the like. As illustrated in Figure 6, the exemplary freeze-dried foam-like structure of the exemplary CMC preform 1000 of Figure 5 is shown with the chemical vapor infiltrated carbon coating deposited thereupon 1300 and encapsulating the fiber bundles 1100.

[0044] Referring now to Figures 1 and 3, at a second possible exemplary fabrication step 320, an exemplary structure may be fabricated within the ceramic preform via a freeze-drying technique using a slurry containing a binder and a particulate material. Slurry additives, e g., dispersant, wetting agent, pH adjustors, surfactants, defoamers, ice crystal modifiers, ice nucleators, and the like, may be used to enhance the properties of the slurry. For example, at an exemplary step 322, the ceramic preform may be infiltrated with a slurry containing a binder material and a particulate material (See Figure 3). The binder materials contemplated herein may include any materials capable of forming a foam-like material when subjected to freeze-drying conditions and, in turn, forming the resultant structure. Suitable binder materials may include, but are not limited to, polyvinyl alcohol, polyvinyl butyral, methyl cellulose, carbo-ethyl cellulose, hydroxypropyl methyl cellulose, gellan gum, gelatin, pectin, aragose gum, konjac gum, carrageenan gum, alginate, sodium alginate, agar gum, non-ionic copolymer surfactant, e.g., Pluronic® F-127, commercially available from Sigma-Aldrich, Inc., St. Louis, Missouri; combinations comprising any one of the foregoing, and the like. The infiltration technique may be any technique capable of filling the interstitial spaces or volumes within the ceramic preform and, in particular, around and between the fibers and / or fibers tows contained therein. The particulate material may include, but are not limited to, carbon-based materials; various carbides, including but not limited to, silicon carbide, boron carbides, zirconium carbides, hafnium carbides, tantalum carbides, niobium carbides, titanium carbides, molybdenum carbides, tungsten carbides, vanadium carbides, chromium carbides, ytterbium carbides, yttrium carbides, combinations comprising any one of the foregoing, and the like; graphite, e.g., flake, particle or fiber forms; carbon nanotubes, carbon nanofibers, diamond particles, combinations comprising any one of the foregoing, and the like; nitrides, including but not limited to, silicon nitrides, titanium nitrides, boron nitrides, zirconium nitrides, hafnium nitrides, niobium nitrides, tantalum nitrides, vanadium nitrides, ytterbium nitrides, yttrium nitrides, combinations comprising any one of the foregoing, and the like; borides, including but not limited to, silicon borides, titanium borides, zirconium borides, hafnium borides, niobium borides, tantalum borides, vanadium borides, ytterbium borides, yttrium borides, combinations comprising anyoneof the foregoing, and the like; or oxides, including but not limited to, aluminum oxides, silicon oxides, tantalum oxides, boron oxides, hafnium oxides, zirconium oxides, ytterbium oxides, yttrium oxides, combinations comprising any one of the foregoing, and the like; metal(s) and metalloid(s), including but not limited to, silicon, boron, zirconium, hafnium, tantalum, niobium, titanium, molybdenum, tungsten, vanadium, chromium, ytterbium, yttrium; alloys comprising any one or more of the aforementioned metal(s) and / or metalloid(s), combinations comprising any one of the foregoing, and the like. The particulate material may exhibit and possess any shape, e.g., particulate, flake or fiber; or size, e.g., nanometer, sub-micron, micron, combinations comprising any one of the foregoing, and the like; may be added to a slurry comprising a solvent, prior to the slurry infiltration taking place. Suitable infiltration techniques may include, but are not limited to, any technique capable of infiltrating a slurry, and its contents, within and throughout the entirety of the preform. For example, suitable infiltration techniques may comprise vacuum infiltration and / or pressure infiltration combinations comprising at least one of the foregoing, and the like. At an exemplary step 324, after infiltration occurs, the exemplary infiltrated ceramic preform may undergo a freeze-drying technique (See Figure 3). The freeze- drying technique may be any technique capable of controlling the transformation of the binder material into a freeze-dried, foam-like binder material, also known as the resultant exemplary structure. Suitable freeze-drying techniques may include, but are not limited to, any technique capable of freezing the slurry, and its constituents, within and throughout the entirety of the preform. Next, at an exemplary step 326, the solvent of the frozen slurry infiltrated preform may be sublimated. Suitable sublimation techniques may include, but are not limited to, any technique capable of converting the solvent of the frozen slurry from a solid phase to a gaseous phase.

[0045] It has been discovered that when the preform containing a slurry containing a binder and particle is freeze dried, the binder forms a "foam-like" material. The resulting foam-like material separates and suspends the particulate material therein such that the distribution of the particulate material becomes significantly more uniform than using elevated temperatures todry. When using heat, the evaporating solvent, for example, may lead to shrinking of the slurry such that the particulate material may become clumped together. By using a freeze-drying technique, the foam-like structure within the infiltrated fiber preform may be controlled, thereby also controlling the spacing and distribution of the particulate material within the foam and, in turn, within the fiber preform too. Upon freeze-drying, the exemplary foam-like binder material, i.e., resultant exemplary structure, may be fabricated.

[0046] Next, at an exemplary step 328, the exemplary ceramic preforms containing the structure may be vapor infiltrated with a gaseous carbon source (See Figure 2). The carbon source may be any gaseous carbon material capable depositing carbon onto the freeze-dried, foam-like structure. Suitable gaseous carbon sources may include, but are not limited to, methane, propane, combinations comprising at least one of the foregoing, and the like. The infiltration technique may be any technique capable of filling the interstitial spaces or volumes within the ceramic preform and, in particular, around and between the fibers and / or fibers tows contained therein. Generally, such an infiltration technique may include, but are not limited to, chemical vapor infiltration (CVI) techniques. Suitable CVI techniques may include, but are not limited to, isothermal CVI, thermal gradient CVI, pressure gradient CVI, low pressure CVI, microwave CVI, combinations comprising at least one of the foregoing, and the like.

[0047] Referring now to Figures 1, 4 and 8-10, at a third possible exemplary fabrication step 330, an exemplary structure may be fabricated using a particle structure technique. For example, at an exemplary step 332, an exemplary structure may be fabricated within the ceramic preform via a freeze-drying technique using a slurry containing a particulate material. Slurry additives, e g., dispersant, wetting agent, pH adjustors, surfactants, defoamers, ice crystal modifiers, ice nucleators, combinations comprising at least one of the foregoing, and the like, may be used to enhance the properties of the slurry. The particulate material may include, but is not limited to, carbon-based materials; various carbides, including but not limited to, silicon carbide, boron carbides, zirconium carbides, hafnium carbides, tantalum carbides, niobium carbides, titanium carbides, molybdenum carbides, tungsten carbides, vanadium carbides, chromium carbides,ytterbium carbides, yttrium carbides, combinations comprising any one of the foregoing, and the like; period graphite, e.g., flake, particle or fiber forms; carbon nanotubes, carbon nanofibers, diamond particles, combinations comprising any one of the foregoing, and the like; nitrides, including but not limited to, silicon nitrides, titanium nitrides, boron nitrides, zirconium nitrides, hafnium nitrides, niobium nitrides, tantalum nitrides, vanadium nitrides, ytterbium nitrides, yttrium nitrides, combinations comprising any one of the foregoing, and the like; borides, including but not limited to, silicon borides, titanium borides, zirconium borides, hafnium borides, niobium borides, tantalum borides, vanadium borides, ytterbium borides, yttrium borides, combinations comprising any one of the foregoing, and the like; or oxides, including but not limited to, aluminum oxides, silicon oxides, tantalum oxides, boron oxides, hafnium oxides, zirconium oxides, ytterbium oxides, yttrium oxides, combinations comprising any one of the foregoing, and the like; metal(s) and metalloid(s), including but not limited to, silicon, boron, zirconium, hafnium, tantalum, niobium, titanium, molybdenum, tungsten, vanadium, chromium, ytterbium, yttrium; alloys comprising any one or more of the aforementioned metal(s) and / or metalloid(s), combinations comprising any one of the foregoing, and the like. The particulate material may exhibit and possess any shape, e.g., particulate, flake or fiber; or size, e.g., nanometer, sub-micron, micron, combinations comprising any one of the foregoing, and the like; may be added to a slurry comprising a solvent, prior to the slurry infiltration taking place. At an exemplary step 334, after infiltration occurs, the exemplary infiltrated ceramic preform may undergo a freeze-drying technique (See Figure 4). The freeze-drying technique may be any technique capable of controlling the transformation of the particulate material into a freeze- dried particulate material, thus becoming the resultant exemplary structure. Suitable freeze- drying techniques may include, but are not limited to, any technique capable of freezing the slurry and particulate material within and throughout the entirety of the CMC preform. Next, at an exemplary step 336, the solvent of the frozen slurry infiltrated preform may be sublimated (See Figures 4 and 8). Suitable sublimation techniques may include, but are not limited to, any technique capable of converting the solvent of the frozen slurry from a solid phase to a gaseous phase. As illustrated in Figure 8, the resultant exemplary CMC preform 2000 contains fiberbundles 2100 encapsulated within an exemplary frozen particulate material structure of the original particulate material 2200.

[0048] It has been discovered that when the preform containing a slurry containing a particulate is frozen, the particulate material forms the structure. The resulting particulate material becomes suspended such that the distribution of the particulate material becomes significantly more uniform than using elevated temperatures to dry. When using heat, the evaporating solvent, for example, may lead to shrinking of the slurry such that the particulate material may become clumped together. By using a freeze-drying technique, the frozen particulate material structure within the infiltrated fiber preform may be controlled, thereby also controlling the spacing and distribution of the particulate material within the fiber preform. Upon freeze-drying, the exemplary resultant frozen particulate material structure may be fabricated.

[0049] Next, at an exemplary step 338, the exemplary ceramic preforms containing the structure may be vapor infiltrated with a gaseous carbon source such that carbon is deposited thereupon (See Figures 4, 9 and 10). The carbon source may be any gaseous carbon material capable depositing carbon onto the frozen particulate material structure. Suitable gaseous carbon sources can include, but are not limited to, methane, propane, combinations comprising at least one of the foregoing, and the like. The infiltration technique may be any technique capable of filling the interstitial spaces or volumes within the ceramic preform and, in particular, around and between the frozen particulate material structure, fibers, fiber bundles and / or fibers tows contained therein. Generally, such an infiltration technique may include, but are not limited to, chemical vapor infiltration (CVI) techniques. Suitable CVI techniques may include, but are not limited to, isothermal CVI, thermal gradient CVI, pressure gradient CVI, low pressure CVI, microwave CVI, combinations comprising at least one of the foregoing, and the like. As illustrated in Figure 9, the exemplary frozen foam-like structure of the exemplary CMC preform 2000 of Figure 8 is shown with the chemical vapor infiltrated carbon coating deposited thereupon 2300 and encapsulating the fiber bundles 2100.

[0050] When employing any one of the aforementioned possible exemplary techniques at exemplary steps 310, 320 or 330, the resultant carbon coated structure contains a large volume of carbon loaded and uniformly distributed onto the structure and throughout the interior surfaces of the ceramic preform. In an at least one exemplary embodiment, carbon may be present in the resultant carbon coated structure in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the ceramic preform.

[0051] Next, at an exemplary step 400, the ceramic preforms containing the carbon coated structure is infiltrated with at least one molten metal, at least one molten metalloid, at least one molten metal alloy, molten metalloid alloy, combinations comprising at least one of the foregoing, and the like. Any melt-infiltration technique may be used to infiltrate the ceramic preform. Whether utilizing any one of the aforementioned molten infiltrants, at an exemplary step 500, the molten infiltrant entering the ceramic preform reacts with the carbon deposited on the exemplary structure 1300 to form carbide(s). The resultant matrix may include, but is not limited to, carbide(s), solidified infiltrant, e.g., high temperature silicides, residual particulate material, potentially residual free carbon, combinations comprising at least one of the foregoing, and the like, within the exemplary CMC preform 1000 to form the Ml matrix material 1400 (See Figure 11). In addition, as illustrated in Figure 10, the exemplary carbon coated structure of the exemplary CMC preform 2000 of Figure 9 is converted into a Ml CMC 2500 comprising a melt- infiltrated ceramic matrix 2400 encapsulating the fiber bundles 2100. In at least one embodiment, the exemplary method disclosed herein fabricates a melt-infiltrated ceramic matrix composite for use in further fabricating gas turbine engine components, such as, but not limited to, engine hot section components, e.g., blades, vanes, shrouds, boas, combinations comprising at least one of the foregoing, and the like.

[0052] While the present disclosure has been particularly described, in conjunction with specific preferred embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is thereforecontemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present disclosure.

Claims

CLAIMSWhat is claimed is:

1. A method for fabricating a melt-infiltrated ceramic matrix composite, comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform; infiltrating at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, within the ceramic preform and in contact with the structure; and reacting at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, with the at least one carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

2. The method according to claim 1, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; andinfiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

3. The method according to claim 1, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; and infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

4. The method according to claim 1, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material;sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

5. The method according to claim 1, wherein the at least one structure comprising the at least one carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the at least one ceramic preform.

6. A melt-infiltrated ceramic matrix composite produced by a process comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform; infiltrating at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, within the ceramic preform and in contact with the structure; and reacting at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, with the at least one carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

7. The melt-infiltrated ceramic matrix composite according to claim 6, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

8. The melt-infiltrated ceramic matrix composite according to claim 6, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; and infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

9. The melt-infiltrated ceramic matrix composite according to claim 6, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

10. The melt-infiltrated ceramic matrix composite according to claim 6, wherein the at least one structure comprising the at least one carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the at least one ceramic preform.

11. A ceramic preform comprising a structure produced by a process comprising the steps of: providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; andfabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform.

12. The ceramic preform according to claim 11, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

13. The ceramic preform according to claim 11, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; andinfiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

14. The ceramic preform according to claim 11, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform; infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

15. The ceramic preform of claim 11, wherein the at least one structure comprising the at least one carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the at least one ceramic preform.

16. A gas turbine engine component comprising a melt-infiltrated ceramic matrix composite produced by a process comprising the steps of:providing at least one ceramic preform comprising at least one fiber, at least one fiber bundle, at least one fiber tow, and combinations comprising at least one of the foregoing; optionally depositing at least one interface coating on the at least one fiber, at least one fiber bundle or at least one fiber tow, and combinations comprising at least one of the foregoing; fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform; infiltrating at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, within the ceramic preform and in contact with the structure; and reacting at least one molten metal, at least one molten metalloid, at least one molten metal alloy, at least one molten metalloid alloy, or combination comprising at least one of the foregoing, with the at least one carbon-containing coating present on or within the structure to form the melt-infiltrated ceramic matrix composite.

17. The gas turbine engine component according to claim 16, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the steps of: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder material to form at least one infiltrated ceramic preform; freeze-drying the at least one binder material within the at least one infiltrated ceramic preform to form at least one frozen infiltrated ceramic preform; sublimating the at least one frozen infiltrated ceramic preform containing the binder to form the at least one structure within; and infiltrating the at least one frozen infiltrated ceramic preform containing the at least one structure with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

18. The gas turbine engine component according to claim 16, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one particulate material to form the at least one frozen infiltrated ceramic preform comprising the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one particulate material to form a structure therein; and infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure with at least one gaseous carbon source to form the at least one structure comprising the at least one carbon-containing coating.

19. The gas turbine engine component according to claim 16, wherein fabricating at least one structure comprising at least one carbon-containing coating within the at least one ceramic preform comprises the following steps: infiltrating the at least one ceramic preform with at least one slurry comprising at least one binder and at least one particulate material to form at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; freezing the at least one infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material; sublimating the at least one frozen infiltrated ceramic preform comprising the at least one binder and the at least one particulate material to form at least one structure within the at least one frozen infiltrated ceramic preform;infiltrating the at least one frozen infiltrated ceramic preform comprising the at least one structure comprising the at least one particulate material with at least one gaseous carbon source material to form the at least one structure comprising the at least one carbon-containing coating.

20. The gas turbine engine component of claim 16, wherein the at least one structure comprising the at least one carbon-containing coating comprises carbon present in an amount of approximately 0.1 volume percent to approximately 70 volume percent based on the total volume of the at least one ceramic preform.

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