Coated ceramic matrix composites (CMC)

Abstract

A method for fabricating a metal-infiltrated ceramic matrix composite, comprises: providing a ceramic fiber preform comprising a fiber tow; depositing an interface coating material around the fiber tow to form an interface coating therearound, and form an interfaced coated ceramic preform containing the interface coated fiber tows; depositing a silicon carbide layer around the interface coated fiber tow; depositing a reaction-barrier coating around the interface coated, silicon carbide coated fiber tow of the interface coated, silicon carbide coated ceramic preform; infiltrating the interface coated, silicon carbide coated ceramic preform with a slurry comprising a carbon source; drying the slurry infiltrated interface coated, silicon carbide coated ceramic preform; and infiltrating the dried slurry infiltrated interface coated, silicon carbide coated ceramic preform with a molten ternary metal alloy, a molten ternary metalloid alloy, a molten ternary metal alloy comprising boron as a constituent, a molten ternary metalloid alloy comprising boron as a constituent, a ternary metal melt, a ternary metalloid melt, a ternary metal melt comprising boron as a constituent, or a ternary metalloid melt comprising boron as a constituent, combinations comprising at least one of the foregoing; to form a melt-infiltrated ceramic matrix composite.

Description

COATED CERAMIC MATRIX COMPOSITES (CMC)CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Patent Application No. 63 / 665,201 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 ceramic matrix composites (CMC) and, in particular, to coated CMCs.BACKGROUND OF THE INVENTION

[0003] In fabricating CMCs, a partially densified chemical vapor infiltrated (CVI) CMC is initially infiltrated by a slurry formulation containing a carbon source, such as, a phenolic resin, a mesophase pitch, carbon black and / or diamond particles. The slurry infiltrated CVI CMC then undergoes a silicon metal or silicon alloy melt infiltration (MI) technique with a binary eutectic system, for example, a Zr-Si, a Hf-Si alloy, or another silicon-metal alloy. Upon infiltration, the melt infiltrated matrix contains free silicon, silicide, recrystallized SiC, and combinations comprising any one of the foregoing. However, when this matrix contacts a CVI SiC layer that protects the fiber tows of the MI CMC, the characterization of microstructures of the MI CMC indicates the aggressiveness of the Si alloy / metal melt. The Si alloy / metal melt attacks the CVI SiC layer that protects the fiber tows. The attack can deteriorate the CVI SiC layer having a phase containing alloy silicide, alloy carbide, and combinations comprising any one of the foregoing. During and post infiltration, the Si alloy / metal melt can also diffuse through the CVI SiC layer and also damage the interface coating (IFC) and the fiber by forming new phases.

[0004] A reason for the reaction of SiC with the Si alloy / metal melt is believed to be the high density of stacking faults in the SiC grains In addition, such reactions are most likely to occur on the outer ceramic tows, that is, tows located proximate to the outer or exterior surface of the CMC, where the tows are more exposed to the incoming Si alloy / metal melt being wicked into the CMC.

[0005] Some major mechanical and thermal properties, e.g., fracture toughness, elongation, thermal shock resistance, thermal conductivity, etc., of the CMC strongly depend on the CVI SiC coating layer performance present in the matrix. The CVI matrix in and around the tows can be critical to protect the interface coating and the fiber. The CVI matrix also can contribute to some of the thermal and mechanical properties of the CMC, in particular its creep resistance. When compromised by silicon infiltration and aggressiveness of the Si alloy / metal melt, the destruction of the CVI SiC coating layer can significantly diminish the properties of the partially densified CVI CMC and the resultant overall MI CMC. As such, there is a need to avoid damage to SiC matrix, interface coating and fibers from the metal infiltrated Si alloy / metal melt.SUMMARY OF THE INVENTION

[0006] According to an embodiment of the present disclosure, there is provided a method for fabricating a metal-infiltrated ceramic matrix composite, comprises the following steps: providing at least one ceramic fiber preform comprising at least one fiber tow; depositing at least one interface coating material around at least one fiber tow to form at least one interface coating therearound, and form at least one interfaced coated ceramic preform containing at least one interface coated fiber tow; depositing at least one silicon carbide layer around at least one interface coated fiber tow to form at least one interface coated, silicon carbide coated ceramic fiber preform; depositing at least one reaction-barrier coating around at least one interface coated, silicon carbide coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform; infiltrating at least one interface coated, silicon carbide coated ceramic preform with a slurry comprising a carbon source to form at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; drying the at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; andinfiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with any one or more the following: at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, at least one ternary metalloid melt comprising boron as a constituent, and combinations comprising at least one of the foregoing; to form a melt-infiltrated ceramic matrix composite comprising at least one metal carbide-containing matrix comprising at least one interface coated, silicon carbide coated, reaction-barrier coated ceramic tows.

[0007] According to another embodiment of the present disclosure, there is provided a metal- infiltrated ceramic matrix composite prepared by a method comprising the following steps: providing at least one ceramic fiber preform comprising at least one fiber tow; depositing at least one interface coating material around at least one fiber tow to form at least one interface coating therearound, and form at least one interfaced coated ceramic preform containing at least one interface coated fiber tows; depositing at least one silicon carbide layer around at least one interface coated fiber tow to form at least one interface coated, silicon carbide coated ceramic fiber preform; depositing at least one reaction-barrier coating around at least one interface coated, silicon carbide coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform; infiltrating at least one interface coated, silicon carbide coated ceramic preform with a slurry comprising a carbon source to form at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; drying the at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; andinfiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with any one or more the following: at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, at least one ternary metalloid melt comprising boron as a constituent, and combinations comprising at least one of the foregoing; to form a melt-infiltrated ceramic matrix composite comprising at least one metal carbide-containing matrix comprising at least interface coated, silicon carbide coated, one reaction-barrier coated ceramic tow.

[0008] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, after performing the third deposition step and before performing the first infiltration step, the method further comprises the step of: depositing at least one additional, optional silicon carbide coating around at least one interface coated, silicon carbide coated, reaction-barrier coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform.

[0009] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, after performing the drying step and before performing the second infiltration step, the method further comprises the step of: infiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with a slurry comprising a boron source.

[0010] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the boron source comprises any one or more of the following: B4C, boron-coated SiC particles, boron-doped carbon-coated SiC particles, and combinations comprising at least one of the foregoing.

[0011] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, all the deposition steps comprise any one or more of the following methods: chemical vapor infiltration, and combinations comprising at least one of the foregoing.

[0012] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the interface coating material comprises a boron nitride-based coating and any one or more of the following materials: pyrolytic carbon, silicon nitride, silicon carbon nitride, silicon carbide, boron carbide, boron nitride (BN), and combinations comprising at least one of the foregoing.

[0013] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the SiC coating around each interface coated, silicon carbide coated fiber tow comprises a continuous SiC coating.

[0014] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, each interface coated, silicon carbide coated fiber tow and each individual fiber of each fiber tow comprises a SiC coating.

[0015] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, each interface coated, silicon carbide coated fiber tow comprises a SiC coating.

[0016] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent, comprises a eutectic alloy or eutectic melt.

[0017] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent, comprises a non-eutectic alloy or eutectic melt.

[0018] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent, comprises any one or more of the following: Zr-Si-B, Hf-Si-B, and combinations comprising at least one of the foregoing.

[0019] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the amount of boron present comprises approximately 5 percent by weight to approximately 15 percent by weight based on a total weight of the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent.

[0020] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the amount of boron present comprises approximately 2 atomic percent to approximately 20 atomic percent based on the total atomic weight of the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent.

[0021] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the carbon source comprises any one or more of the following: diamonds, graphite, hydrocarbon containing resins, hydrocarbon containing polymers, hydrocarbon containing binders, carbide formers, carbides, and combinations comprising at least one of the foregoing.

[0022] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the hydrocarbon resins comprise any one or more of the following: phenolic resin, furan resin, and combinations comprising at least one of the foregoing.

[0023] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the hydrocarbon containing polymers comprise benzoxazine and combinations comprising benzoxazine.

[0024] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the hydrocarbon resins comprise any one or more of the following: cellulose ether, furfuryl alcohol, and combinations comprising at least one of the foregoing.

[0025] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the carbide formers comprise any one or more of: silicon, boron, zirconium, hafnium, titanium, tantalum, molybdenum, tungsten, vanadium, niobium, chromium, ytterbium, yttrium combinations comprising at least one of the foregoing.

[0026] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the carbides comprise any one or more of: silicon carbides, boron carbides, zirconium carbides, hafnium carbides, titanium carbides, tantalum carbides, molybdenum carbides, tungsten carbides, vanadium carbides, niobium carbides, chromium carbides, ytterbium carbides, yttrium carbides combinations comprising at least one of the foregoing.

[0027] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, after performing the third deposition step and before performing the first infiltration step, the method further comprises the step of depositing at least one additional, optional silicon carbide coating around at least one interface coated, silicon carbide coated, reaction-barrier coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform.

[0028] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, after performing the drying step and before performing the second infiltration step, the method further comprises the step of infiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with a slurry comprising a boron source.

[0029] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the boron source comprises any one or more of the following: B4C, boron-coated SiC particles, boron-doped carbon-coated SiC particles, boron, borides, boron silicides, boric acid, ammonium pentaborate, potassium pentaborate, sodium pentaborate, polyborosilazanes, carboranes, boronated polymer particles, micro / nanoparticles of elemental boron particles, titanium diboride, zirconium diboride, magnesium diboride, pre-alloyed micro / nanoparticles of Si-B-Mo, Si-B-Ti, and combinations comprising at least one of the foregoing.

[0030] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the SiC coating around the interface coated, silicon carbide coated fiber tow comprises a continuous SiC coating.

[0031] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, each interface coated, silicon carbide coated fiber tow and each individual fiber of each fiber tow comprises at least one SiC coating.

[0032] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, each interface coated, silicon carbide coated fiber tow comprises at least one SiC coating.

[0033] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, theternary metal melt comprising boron as a constituent, the ternary metalloid melt comprising boron as a constituent, comprises any one or more of the following: Zr-Si-B, Hf-Si-B, and combinations comprising at least one of the foregoing.

[0034] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the amount of boron present comprises approximately 5 percent by weight to approximately 15 percent by weight based on a total weight of the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent.

[0035] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the amount of boron present comprises approximately 2 atomic percent to approximately 20 atomic percent based on the total atomic weight of the molten ternary metal alloy, the molten ternary metalloid alloy, the molten ternary metal alloy comprising boron as a constituent, the molten ternary metalloid alloy comprising boron as a constituent, the ternary metal melt, the ternary metalloid melt, the ternary metal melt comprising boron as a constituent, or the ternary metalloid melt comprising boron as a constituent.

[0036] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the carbon source comprises any one or more of the following: diamonds, graphite, hydrocarbon containing resins, hydrocarbon containing polymers, hydrocarbon containing binders, carbide formers, carbides, and combinations comprising at least one of the foregoing.

[0037] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the hydrocarbon resins comprise any one or more of the following: phenolic resin, furan resin, and combinations comprising at least one of the foregoing.

[0038] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the hydrocarbon containing polymers comprise benzoxazine and combinations comprising benzoxazine.

[0039] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the hydrocarbon resins comprise any one or more of the following: cellulose ether, furfuryl alcohol, and combinations comprising at least one of the foregoing.

[0040] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the carbide formers comprise any one or more of: silicon, boron, zirconium, hafnium, titanium, tantalum, molybdenum, tungsten, vanadium, niobium, combinations comprising at least one of the foregoing.

[0041] In further embodiments of the present disclosure, including further embodiments of the above-exemplary embodiments, the carbides comprise any one or more of: silicon carbides, boron carbides, zirconium carbides, hafnium carbides, titanium carbides, tantalum carbides, molybdenum carbides, tungsten carbides, vanadium carbides, niobium carbides, combinations comprising at least one of the foregoing.BRIEF DESCRIPTION OF FIGURES

[0042] 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:

[0043] Figure l is a flowchart illustrating a method for forming a MI CMC.

[0044] Figure 2 is a microphotograph depicting a melt attack of a fiber in the matrix of a CMC.

[0045] Figure 3 is a microphotograph depicting a melt attack and deterioration of a chemical vapor infiltrated silicon carbide in the matrix of a CMC.

[0046] Figure 4 is a flowchart illustrating an exemplary method for preventing a melt attack of a chemical vapor infiltrated silicon carbide in the matrix of CMC and / or of a fiber in the matrix of CMC.

[0047] Figure 5 is a flowchart illustrating an exemplary alternative set of steps within the hash- marked box of the exemplary method illustrated in Figure 4.

[0048] Figure 6 is a Zr-Si-B phase diagram that contains an exemplary Zr-Si-B ternary alloy system for use herein.

[0049] Figure 7 is a table disclosing various phases of the exemplary Zr-Si-B ternary alloy system of Figure 6.

[0050] Figure 8 is a Hf-Si-B phase diagram that contains an exemplary Hf-Si-B ternary alloy system for use herein.

[0051] Figure 9 is a table disclosing various phases of the exemplary Hf-Si-B ternary alloy system of Figure 8.

[0052] Figure 10 is a scanning electron microscope (SEM) image depicting a sample of ceramic fibers coated by a protective PyC coating layer.DETAILED DESCRIPTION OF THE INVENTION

[0053] 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.

[0054] Referring again to Figure 1, a method 100 for fabricating a MI CMC includes, at a step 110, providing a ceramic fiber preform containing a plurality of fiber tows. Once formed, the fiber tows at a step 120 are coated via CVI with an interface coating (IFC) to form an IFC ceramic preform containing a plurality of IFC fiber tows. Next, the IFC fiber tows at a step 130 are coated again via CVI with SiC to form an IFC SiC ceramic preform containing a plurality of IFC SiC fiber tows. Next, the resultant relatively porous IFC SiC ceramic preform at a step 140 is infiltrated with a slurry containing a carbon source and dried. Lastly, at a step 150, the slurry infiltrated IFC SiC ceramic preform is infiltrated again with a molten metal; a molten metalloid, e.g., Si; a molten metal alloy; or a molten metalloid alloy, e.g., a Si-containing alloy, to form a melt-infiltrated (MI) CMC containing a Si / SiC matrix having the plurality of IFC SiC ceramic tows disposed therein.

[0055] As discussed above, the mechanical properties of MI CMCs depend on the amount of the load bearing fiber tows remaining after undergoing metal infiltration with at least one metal, at least one metalloid, at least one metal alloy, or at least one metalloid alloy, combinations comprising at least one of the foregoing, and the like, and having silicon carbide form that consumes too many fiber tows. Hence, a low conversion of fiber tows is favorable. At least one approach may involve improving the coating applied to the fibers of the CMC preform so as to improve damage tolerance resulting from the silicon carbide formation (See again Figure 2). At least one other approach may involve modifying the at least one metal, at least one metalloid, at least one metal alloy, or at least one metalloid alloy, and, in turn, controlling the resultant silicon carbide formation (See again Figure 3).

[0056] The present disclosure is directed to an exemplary method of fabricating a MI CMC based on improving the aforementioned method by further incorporating a first additional step of depositing a reaction-barrier coating via CVI around at least one IFC SiC coated fiber tow of at least one IFC SiC ceramic preform and, at least one step later, a second additional step of infiltrating the IFC SiC ceramic preform with a boron-doped silicon-containing metalloid alloy melt to form at least one MI CMC.

[0057] Referring now to Figure 4, an exemplary method 400 for fabricating a MI CMC includes, at an exemplary step 410, providing at least one ceramic preform that may contain at least onefiber tow. Next, at an exemplary step 420, an interface coating material may be deposited on and around at least one fiber tow to form at least one interface coating (IFC), and form an IFC ceramic preform containing a plurality of IFC fiber tows. The IFC may exhibit and possess an exemplary thickness of between about 200 nm and about 3 gm. Deposition may take place using a technique, such as but not limited to, chemical vapor infiltration (CVI), atomic layer deposition (ALD), combinations comprising any one of the foregoing, and the like. The IFC materials may be any materials suitable for promoting debonding between SiC matrix and material of the fibers and / or fiber tows. Suitable IFC materials may include boron nitride (BN) as a single layer or in combination as multilayers with, but are not limited to, carbon (C), silicon nitride (SisN^, silicon carbon nitride (SiCN), silicon carbide (SiC), boron carbide (B4C), boron nitride (BN), and combinations comprising any one of the foregoing, and the like.

[0058] Next, at an exemplary step 430, at least one SiC layer may be deposited on and around at least one IFC fiber tow to form at least one IFC SiC ceramic preform that may contain at least one IFC SiC fiber tow. The SiC layer may exhibit and possess a thickness of between about 2 microns and about 40 microns. 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. When carrying out exemplary method 400, although a SiC layer may be deposited, additional materials suitable for promoting adhesion and compatibility between such materials and exemplary reaction-barrier coating materials may be utilized. Additional suitable materials may include, but are not limited to, carbon, borides, nitrides, boron carbide materials similar to SiC, combinations comprising any one of the foregoing, and the like.

[0059] Next, at an exemplary step 440, at least one exemplary reaction-barrier coating may be deposited around at least one IFC SiC ceramic tow of the IFC SiC ceramic preform. Generally, exemplary reaction-barrier coatings disclosed herein may exhibit and possess a thickness of between about 100 nm and about 10 pm. In particular, exemplary reaction-barrier coatings disclosed herein may exhibit and possess a thickness of between about 1 pm about 2 pm. Deposition may take place using a technique, such as but not limited to, chemical vapor infiltration(CVI), atomic layer deposition (ALD), combinations comprising any one of the foregoing, and the like. For example, when considering combinations of the aforementioned methods, at least one layer comprising PyC may be applied via CVI followed by at least one layer comprising particulate B4C being applied via a slurry infdtration technique. In yet another example, at least one layer comprising CVI PyC may be applied followed by at least one layer comprising, e.g., a CVI SiC layer or a CVI B4C layer, being applied.

[0060] In carrying out exemplary step 440, whether by slurry infiltration, CVI, a combination thereof, and the like, at least one exemplary reaction-barrier coating may include material, such as, but not limited to, silicon carbide (SiC), pyrolytic carbon (PyC), silicon nitride (SislSU), silicon carbon nitride (SiCN), boron carbide (B4C), combinations comprising any one of the foregoing, and the like. When selecting B4C as the exemplary reaction-barrier coating, the B4C also serves as a source material for the boron that dopes the silicon-containing metalloid alloy which melt infiltrates the CMC. For instance, when later carrying out exemplary step 460 of the exemplary method, at least one exemplary reaction-barrier coating material, e.g., B4C, may also react with at least one exemplary silicon-containing metalloid alloy. The resultant reaction product may be a new phase, e.g., a boron-doped silicon-containing metalloid alloy, depending upon the reactionbarrier coating and silicon-containing metalloid alloy, and their respective melt temperatures. However, prior to carrying out exemplary step 460, and after carrying out exemplary step 440, the resultant intermediate product may be a relatively porous SiC-SiC CMC with IFC. By “relatively porous”, the porosity of the intermediate product may be between approximately 5 percent by volume and approximately 45 percent by volume based on the total volume of the intermediate product. In particular, the porosity of the intermediate product may be between approximately 25 percent by volume and approximately 38 percent by volume based on the total volume of the intermediate product.

[0061] Next, at an exemplary step 445, an additional, and optional, exemplary SiC layer may be deposited on and around at least one IFC fiber tow of the relatively porous SiC-SiC CMC with IFC to form at least one Si-SiC ceramic preform that may contain at least one IFC SiC fiber tow. The additional, optional exemplary SiC layer may exhibit and possess a thickness of between about2 microns and about 40 microns. Deposition may take place using a technique, such as but not limited to, chemical vapor infiltration (CVI), atomic layer deposition (ALD), combinations thereof, and the like. When carrying out exemplary method 400, although a SiC layer may be deposited, additional materials suitable for promoting adhesion and compatibility between such materials and exemplary reaction-barrier coating materials may be utilized. Additional suitable materials may include, but are not limited to, carbon, materials similar to SiC, combinations thereof, and the like.

[0062] At an exemplary step 450, at least one resultant relatively porous SiC-SiC CMC with IFC may be infiltrated with a slurry containing, but not limited to, a carbon source material. The slurry infiltrated SiC-SiC CMC with IFC may then undergo pyrolysis to yield carbon deposited therein. In at least one other embodiment, the slurry may further include a boron source material. The boron source material may include any material capable of depositing boron after undergoing decomposition. Suitable boron source materials may include, but are not limited to, B4C, boron- coated SiC particles, boron-doped carbon-coated SiC particles, boron, borides, boron silicides, boric acid, ammonium pentaborate, potassium pentaborate, sodium pentaborate, polyborosilazanes, carboranes, boronated polymer particles, micro / nanoparticles of elemental boron particles, titanium diboride, zirconium diboride, magnesium diboride, pre-alloyed micro / nanoparticles of Si-B-Mo, Si-B-Ti, combinations thereof, and the like. In this other embodiment, after undergoing pyrolysis, both carbon and boron may be deposited within the relatively porous SiC-SiC CMC with IFC. The carbon source materials may include diamond and / or graphite. Additionally, carbon source materials may include any material capable of depositing carbon after undergoing decomposition. Suitable carbon source materials may include, but are not limited to, hydrocarbon containing resins, e.g., phenolic resin, furan resin, combinations comprising at least one of the foregoing, and the like; hydrocarbon containing polymers, e.g., benzoxazine, combinations comprising at least one of the foregoing, and the like; hydrocarbon containing binders, e.g., Methocel™ (commercially available from ChemPoint® located in Bellevue, Washington), furfuryl alcohol, combinations comprising at least one of the foregoing, and the like; carbide formers, also known as carbide forming materials, e.g., silicon, boron, zirconium, hafnium, titanium, tantalum, molybdenum, tungsten, vanadium, niobium, chromium,ytterbium, yttrium combinations comprising at least one of the foregoing, and the like; and, and, various carbides, e.g., silicon carbides, boron carbides, zirconium carbides, hafnium carbides, titanium carbides, tantalum carbides, molybdenum carbides, tungsten carbides, vanadium carbides, niobium carbides, chromium carbides, ytterbium carbides, yttrium carbides combinations comprising at least one of the foregoing, and the like.

[0063] While the boron source material may be included when carrying out exemplary step 450, in at least one other embodiment, an additional exemplary step 455 may be performed after exemplary step 450 and before exemplary step 465 (See Figure 5). At exemplary step 455, at least one slurry infiltrated SiC-SiC CMC with IFC may be further infiltrated with at least one additional slurry containing at least one boron source material. The slurry infiltrated SiC-SiC CMC with IFC may then undergo further pyrolysis to yield boron deposited therein. Again, the boron source material may include any material capable of depositing boron after undergoing decomposition. Suitable boron source materials may include, but are not limited to, B4C, boron-coated SiC particles, boron-doped carbon-coated SiC particles, boron, borides, boron silicides, boric acid, ammonium pentaborate, potassium pentaborate, sodium pentaborate, polyborosilazanes, carboranes, boronated polymer particles, micro / nanoparticles of elemental boron particles, titanium diboride, zirconium diboride, magnesium diboride, pre-alloyed micro / nanoparticles of Si- B-Mo, Si-B-Ti, combinations comprising any one of the foregoing, and the like.

[0064] Lastly, at an exemplary step 460, at least one slurry infiltrated SiC-SiC CMC with IFC may be infiltrated with at least one exemplary molten boron-doped metal or metalloid, or at least one boron-containing metal alloy or metalloid alloy, to form a melt-infiltrated (MI) CMC containing at least one metal carbide-containing matrix having at least one reaction-barrier coated SiC ceramic tows with IFC disposed therein (See Figure 4). In an exemplary alternative embodiment, at an exemplary step 465, at least one slurry infiltrated SiC-SiC CMC with IFC may be infiltrated with at least one molten metal, at least one molten metalloid, at least one molten metal alloy, or at least one molten metalloid alloy to form a melt-infiltrated (MI) CMC containing at least one metal carbide-containing matrix having at least one reaction-barrier coated SiC ceramic tows with IFC disposed therein (See Figure 5). The alternative embodiment reflects boron is added in exemplarystep 455, thus alleviating the need to add at least one exemplary molten boron-doped metal, at least one exemplary molten boron-doped metalloid, at least one exemplary boron-containing metal alloy, at least one exemplary boron-containing metalloid alloy via melt-infiltration.

[0065] In carrying out exemplary step 460, the exemplary boron-doped metalloid alloy may include silicon with other constituents from transition metals, such as, but not limited to, molybdenum, zirconium, hafnium, titanium, chromium, tungsten, platinum, tantalum, iridium, yttrium, vanadium, niobium, and / or additional constituents from metalloids, basic metals, or lanthanides capable of forming binary alloys with, for example, boron, aluminum, ytterbium, combinations comprising any one of the foregoing, and the like. Suitable exemplary boron-doped silicon-containing binary metalloid alloys may include, but not limited to, boron-doped molybdenum-silicon, boron-doped zirconium-silicon, boron-doped hafnium-silicon, boron-doped titanium-silicon, boron-doped chromium-silicon, boron-doped tungsten-silicon, boron-doped platinum-silicon, boron-doped tantalum-silicon, boron-doped iridium-silicon, boron-doped yttrium-silicon, boron-doped vanadium-silicon, boron-doped niobium-silicon, boron-doped aluminum-silicon, boron-doped ytterbium-silicon, amongst other possible boron-doped silicon- containing binary metalloid alloys. For instance, an exemplary boron-doped Si-Hf metalloid alloy may contain silicon present in an amount of between approximately 55 percent by weight and approximately 65 percent by weight based on the weight of the metalloid alloy; hafnium present in an amount of between approximately 30 percent by weight and approximately 40 percent by weight based on the weight of the metalloid alloy; and, boron present in an amount of between approximately 5 percent by weight and approximately 15 percent by weight based on the weight of the metalloid alloy. In another exemplary embodiment, an exemplary boron-doped Si-Zr metalloid alloy may contain silicon present in an amount of between approximately 65 percent by weight and approximately 75 percent by weight based on the weight of the metalloid alloy; hafnium present in an amount of between approximately 20 percent by weight and approximately 30 percent by weight based on the weight of the metalloid alloy; and, boron present in an amount of between approximately 5 percent by weight and approximately 15 percent by weight based on the weight of the metalloid alloy.

[0066] Suitable exemplary boron-containing ternary metalloid alloys may include, but are not limited to, molybdenum-silicon-boron, niobium-silicon-boron, titanium-silicon-boron, zirconium- silicon-boron, hafnium-silicon-boron, molybdenum-silicon-boron amongst other possible ternary metalloid alloy constituent combinations. In particular, when carrying out the exemplary method disclosed herein, zirconium-silicon-boron and hafnium-silicon-boron are suitable exemplary boron-doped metalloid alloys. Referring now to Figures 6-9, a Zr-Si-B phase diagram, including a phase region table (See Figures 6 and 7), and a Hf-Si-B phase diagram, including a phase region table (See Figures 8 and 9) are shown. Referring specifically to Figure 6, an exemplary Zr-Si-B ternary metalloid alloy may contain Zr present in an amount of between approximately 1 atomic percent and approximately 24 atomic percent; Si present in amount of between approximately 62 atomic percent and approximately 96 atomic percent; and, B present in an amount between approximately 3 atomic percent and approximately 20 atomic percent. The Table of Figure 7 estimates the percentages of the Zr, Si and B phases within the exemplary Zr-Si-B ternary metalloid alloy that exhibits and possesses a melting point less than 1 ,500°C (2,732°F). Referring specifically to Figure 8, an exemplary Hf-Si-B ternary metalloid alloy may contain Hf present in an amount of between approximately 3 atomic percent and approximately 32 atomic percent; Si present in amount of between approximately 65 atomic percent and approximately 91 atomic percent; and, B present in an amount between approximately 2 atomic percent and approximately 13 atomic percent. The Table of Figure 9 estimates the percentages of the Hf, Si and B phases within the exemplary Hf-Si-B ternary metalloid alloy that exhibits and possesses a melting point less than l,500°C (2,732°F).

[0067] The exemplary boron-doped metals, boron-doped metalloids, boron-containing metal alloys, boron-containing metalloid alloys, combinations comprising at least one of the foregoing, and the like, contemplated herein counteract the incomplete conversion of carbon to SiC that, in turn, leaves unreacted Si remaining in the resultant matrix. The unreacted Si impairs the oxidation resistance and mechanical properties of aresultant CMC at temperatures above 2,500°F (1,371°C). In carrying out the exemplary method disclosed herein, adding boron to create an exemplary ternary metal alloys, ternary metalloid alloys, combinations comprising at least one of the foregoing, and the like, and, in turn, a resultant exemplary matrix material, may significantlyreduce the grain coarsening effect and dissolution of CVI SiC in the unreacted Si remaining. Grain coarsening occurs due to the stacking fault and high surface area of the SiC causing an unstable configuration within the matrix of the MI CMC. Boron may assist reducing the grain coarsening effect by acting as a dopant in the SiC matrix. In turn, the observed stacking faults may be eliminated and the resultant SiC crystalline structure of the matrix may be stabilized. In addition, adding boron may increase the solubility of carbon in the unreacted Si remaining, as well as diamond, graphite, and other carbon sources. At the melting point of Si, that is, 1414°C (2,577°F), adding, for example, 2 wt.% of boron to a Si-containing binary alloy and transitioning to a ternary metal alloys, ternary metalloid alloys, combinations comprising at least one of the foregoing, and the like, results in the solubility of carbon becoming comparable to the solubility of carbon in unreacted Si remaining at a melting point of, e.g., greater than 1500°C (2,732°F).

[0068] Referring now to Figure 10, an SEM image depicting a sample of ceramic fibers 40 coated by a protective PyC coating layer 50 that, in turn, completely eliminated an attack by melt on the ceramic fibers. The amount of free, unreacted Si remaining, amount of reaction-formed SiC, and resulting carbon phases may be estimated using SEM image processing, along with machine learning models. In doing so, each respective phase and / or material can be separated, and each respective phase and / or material quantified.

[0069] 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 therefore contemplated 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

What is claimed is:

1. A method for fabricating a metal -infiltrated ceramic matrix composite, comprises the following steps: providing at least one ceramic fiber preform comprising at least one fiber tow; depositing at least one interface coating material around at least one fiber tow to form at least one interface coating therearound, and form at least one interfaced coated ceramic preform containing at least one interface coated fiber tow; depositing at least one silicon carbide layer around at least one interface coated fiber tow to form at least one interface coated, silicon carbide coated ceramic fiber preform; depositing at least one reaction-barrier coating around at least one interface coated, silicon carbide coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform; infiltrating at least one interface coated, silicon carbide coated ceramic preform with a slurry comprising a carbon source to form at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; drying the at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; and infiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with any one or more the following: at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, at least one ternary metalloid melt comprising boron as a constituent, and combinations comprising at least one of the foregoing; to form a melt-infiltratedceramic matrix composite comprising at least one metal carbide-containing matrix comprising at least one interface coated, silicon carbide coated, reaction-barrier coated ceramic tows.

2. The method of claim 1, wherein after performing the third deposition step and before performing the first infiltration step, further comprising the step of: depositing at least one additional, optional silicon carbide coating around at least one interface coated, silicon carbide coated, reaction-barrier coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform; wherein after performing the drying step and before performing the second infiltration step, further comprising the step of: infiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with a slurry comprising a boron source; and, wherein the boron source comprises any one or more of the following: B4C, boron-coated SiC particles, boron-doped carbon-coated SiC particles, boron, borides, boron silicides, boric acid, ammonium pentaborate, potassium pentaborate, sodium pentaborate, polyborosilazanes, carboranes, boronated polymer particles, micro / nanoparticles of elemental boron particles, titanium diboride, zirconium diboride, magnesium diboride, pre-alloyed micro / nanoparticles of Si- B-Mo, Si-B-Ti, and combinations comprising at least one of the foregoing.

3. The method of claim 1, wherein all the depositing steps comprise any one or more of the following methods: chemical vapor infiltration, chemical vapor deposition, and combinations comprising at least one of the foregoing.

4. The method of claim 1, wherein the interface coating material comprises a boron nitridebased coating and any one or more of the following materials: carbon (C), silicon nitride (SisN^, silicon carbon nitride (SiCN), silicon carbide (SiC), boron carbide (B4C), boron nitride (BN), and combinations comprising at least one of the foregoing.

5. The method of claim 1, wherein at least one SiC coating around at least one interface coated, silicon carbide coated fiber tow comprises at least one continuous SiC coating.

6. The method of claim 1, wherein each at least one interface coated, silicon carbide coated fiber tow and each individual fiber of each fiber tow comprises at least one SiC coating.

7. The method of claim 1, wherein each at least one interface coated, silicon carbide coated fiber tow comprises at least one SiC coating.

8. The method of claim 1, wherein at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternary metalloid melt comprising boron as a constituent, comprises a eutectic alloy or eutectic melt.

9. The method of claim 1, wherein at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternary metalloid melt comprising boron as a constituent, comprises a non-eutectic alloy or non-eutectic melt.

10. The method of claim 1, wherein at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternary metalloid melt comprising boron as a constituent, comprises any one or more of the following: Zr-Si-B, Hf-Si-B, and combinations comprising at least one of the foregoing.

11. The method of claim 1, wherein the amount of boron present comprises approximately 5 percent by weight to approximately 15 percent by weight based on a total weight of at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternarymetalloid melt comprising boron as a constituent; wherein the amount of boron present comprises approximately 2 atomic percent to approximately 20 atomic percent based on the total atomic weight of the at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternary metalloid melt comprising boron as a constituent.

12. The method of claim 1, wherein the carbon source comprises any one or more of the following: diamonds, graphite, hydrocarbon containing resins, hydrocarbon containing polymers, hydrocarbon containing binders, carbide formers, carbides, and combinations comprising at least one of the foregoing; wherein the hydrocarbon resins comprise any one or more of the following: phenolic resin, furan resin, and combinations comprising at least one of the foregoing; wherein the hydrocarbon containing polymers comprise benzoxazine and combinations comprising benzoxazine; wherein the hydrocarbon resins comprise any one or more of the following: cellulose ether, furfuryl alcohol, and combinations comprising at least one of the foregoing; wherein the carbide formers comprise any one or more of: silicon, boron, zirconium, hafnium, titanium, tantalum, molybdenum, tungsten, vanadium, niobium, chromium, ytterbium, yttrium, combinations comprising at least one of the foregoing; and, carbides comprising any one or more of: silicon carbides, boron carbides, zirconium carbides, hafnium carbides, titanium carbides, tantalum carbides, molybdenum carbides, tungsten carbides, vanadium carbides, niobium carbides, chromium carbides, ytterbium carbides, yttrium carbides, and combinations comprising at least one of the foregoing.

13. A metal-infiltrated ceramic matrix composite prepared by a method comprising the following steps: providing at least one ceramic fiber preform comprising at least one fiber tow;depositing at least one interface coating material around at least one fiber tow to form at least one interface coating therearound, and form at least one interfaced coated ceramic preform containing at least one interface coated fiber tows; depositing at least one silicon carbide layer around at least one interface coated fiber tow to form at least one interface coated, silicon carbide coated ceramic fiber preform; depositing at least one reaction-barrier coating around at least one interface coated, silicon carbide coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform; infiltrating at least one interface coated, silicon carbide coated ceramic preform with a slurry comprising a carbon source to form at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; drying the at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform; and infiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with any one or more the following: at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, at least one ternary metalloid melt comprising boron as a constituent, and combinations comprising at least one of the foregoing; to form a melt-infiltrated ceramic matrix composite comprising at least one metal carbide-containing matrix comprising at least interface coated, silicon carbide coated, one reaction-barrier coated ceramic tow.

14. The metal-infiltrated ceramic matrix composite of claim 13, wherein after performing the third deposition step and before performing the first infiltration step, further comprising the step of: depositing at least one additional, optional silicon carbide coating around at least one interface coated, silicon carbide coated, reaction-barrier coated fiber tow of at least one interface coated, silicon carbide coated ceramic preform; wherein after performing the drying step and beforeperforming the second infiltration step, further comprising the step of: infiltrating the dried at least one slurry infiltrated interface coated, silicon carbide coated ceramic preform with a slurry comprising a boron source; and, wherein the boron source comprises any one or more of the following: B4C, boron-coated SiC particles, boron-doped carbon-coated SiC particles, boron, borides, boron silicides, boric acid, ammonium pentaborate, potassium pentaborate, sodium pentaborate, polyborosilazanes, carboranes, boronated polymer particles, micro / nanoparticles of elemental boron particles, titanium diboride, zirconium diboride, magnesium diboride, pre-alloyed micro / nanoparticles of Si-B-Mo, Si-B-Ti, and combinations comprising at least one of the foregoing.

15. The metal -infiltrated ceramic matrix composite of claim 13, wherein at least one SiC coating around at least one interface coated, silicon carbide coated fiber tow comprises at least one continuous SiC coating.

16. The metal-infiltrated ceramic matrix composite of claim 13, wherein each at least one interface coated, silicon carbide coated fiber tow and each individual fiber of each fiber tow comprises at least one SiC coating.

17. The metal-infiltrated ceramic matrix composite of claim 13, wherein each at least one interface coated, silicon carbide coated fiber tow comprises at least one SiC coating.

18. The metal-infiltrated ceramic matrix composite of claim 13, at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, at least one ternary metalloid melt comprising boron as a constituent, comprises any one or more of the following: Zr-Si-B, Hf-Si-B, and combinations comprising at least one of the foregoing.

19. The metal -infiltrated ceramic matrix composite of claim 13, wherein the amount of boron present comprises approximately 5 percent by weight to approximately 15 percent by weight basedon a total weight of at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternary metalloid melt comprising boron as a constituent; wherein the amount of boron present comprises approximately 2 atomic percent to approximately 20 atomic percent based on the total atomic weight of the at least one molten ternary metal alloy, at least one molten ternary metalloid alloy, at least one molten ternary metal alloy comprising boron as a constituent, at least one molten ternary metalloid alloy comprising boron as a constituent, at least one ternary metal melt, at least one ternary metalloid melt, at least one ternary metal melt comprising boron as a constituent, or at least one ternary metalloid melt comprising boron as a constituent.

20. The metal -infiltrated ceramic matrix composite of claim 13, wherein the carbon source comprises any one or more of the following: diamonds, graphite, hydrocarbon containing resins, hydrocarbon containing polymers, hydrocarbon containing binders, carbide formers, carbides, and combinations comprising at least one of the foregoing; wherein the hydrocarbon resins comprise any one or more of the following: phenolic resin, furan resin, and combinations comprising at least one of the foregoing; wherein the hydrocarbon containing polymers comprise benzoxazine and combinations comprising benzoxazine; wherein the hydrocarbon resins comprise any one or more of the following: cellulose ether, furfuryl alcohol, and combinations comprising at least one of the foregoing; wherein the carbide formers comprise any one or more of: silicon, boron, zirconium, hafnium, titanium, tantalum, molybdenum, tungsten, vanadium, niobium, chromium, ytterbium, yttrium, combinations comprising at least one of the foregoing; and, carbides comprising any one or more of: silicon carbides, boron carbides, zirconium carbides, hafnium carbides, titanium carbides, tantalum carbides, molybdenum carbides, tungsten carbides, vanadium carbides, niobium carbides, chromium carbides, ytterbium carbides, yttrium carbides, and combinations comprising at least one of the foregoing.

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