Method for joining ceramic parts to form a single ceramic part

Abstract

A method for forming a single ceramic component is provided. The method can include positioning a brazing reactant layer in a contact area between a first dense ceramic component and a second dense ceramic component; positioning a packaging material around at least a portion of the first dense ceramic component or the second dense ceramic component; positioning at least one infiltration source in fluid communication with the brazing reactant layer; and thereafter, heating the at least one infiltration source, the packaging material, the first dense ceramic component, and the second dense ceramic component to a brazing temperature equal to or greater than a melting point of at least one phase of an infiltration composition, such that the at least one phase of the infiltration composition melts and flows into the brazing reactant layer and reacts with ceramic precursor compounds therein to form a ceramic material.

Description

TECHNICAL FIELD

[0001] The present subject matter relates generally to ceramic components and joining them together. BACKGROUND

[0002] More commonly, ceramic components are used in various applications, such as gas turbine engines. In particular, ceramic matrix composite (CMC) materials are more commonly used in various high temperature applications. For example, it is of particular interest to replace components within the combustion gas flow path of a gas turbine engine with components made of CMC materials because CMC materials can withstand relatively extreme temperatures. Layers of CMC material can be laid up to form a preform component, which can then be heat treated (e.g., cured or burned out) to produce a high carbon residue in the preform, and subsequently chemically treated (e.g., infiltrated with a silicon melt) to result in a component formed of CMC material having a desired chemical composition. BRIEF DESCRIPTION OF DRAWINGS

[0003] A complete and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification, which is to be referred to in conjunction with the drawings, wherein:

[0004] Figure 1 is a schematic cross-section of exemplary dense ceramic components positioned together for joining with a braze reactant layer;

[0005] Figure 2 is a schematic cross-section of other exemplary dense ceramic components positioned together for joining with a braze reactant layer;

[0006] Figure 3 is a schematic cross-section of a single ceramic component such as formed by Figure 1 or Figure 2 is a schematic cross-section of a single ceramic component such as formed by

[0007] Figure 4 is a schematic cross-section view of an exemplary gas turbine engine in accordance with various embodiments of the present subject matter; and

[0008] Figure 5 is a flow chart of an exemplary method of joining dense ceramic components together to form a single ceramic component such as shown in Figure 3 DETAILED DESCRIPTION

[0009] Reference will now be made in detail to the presently preferred embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations to refer to various features of the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0010] ​The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, unless otherwise explicitly specified, all embodiments described herein are to be considered exemplary in nature.

[0011] The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0012] The term “at least one of’ in the context of “at least one of A, B, and C” means only A, only B, only C, or any combination of A, B, and C.

[0013] In the present disclosure, when a layer is described as being “on” or “over” another layer or substrate, it is understood that the layers can be directly contacting one another or have another layer or feature between them unless explicitly stated to the contrary. Thus, the terms are simply describing the relative position of the layers to one another and do not necessarily mean “on top of’ as the relative position above or below is dependent on the orientation of the device to the viewer.

[0014] In the present disclosure, the common chemical abbreviations for chemical elements are used (e.g., the abbreviations commonly found in the Periodic Table of the Elements) to discuss the chemical elements. For example, hydrogen is represented by its common chemical abbreviation, H; helium is represented by its common chemical abbreviation, He; and so forth.

[0015] A “dense ceramic part” is a ceramic having less than 70% porosity by volume. Additionally, the dense ceramic part is in a finished state, no additional processing steps aimed at improving its mechanical properties will be performed. Typically, the dense ceramic part has a mechanical stress higher than 20 MPa, measured by 3-point bending test according to ASTM D790-17.

[0016] As used herein, “melting point” refers to the temperature or range of temperatures at which a solid becomes a liquid. If the melting point is a range of temperatures, the melting point refers to the lowest temperature in the range at which the solid becomes a liquid.

[0017] Large CMC parts or pieces having complex geometries can be difficult to fabricate in a single piece or at an acceptable yield. Therefore, improved methods of fabricating CMC parts are needed.

[0018] The present disclosure generally relates to methods of forming a single ceramic component by joining at least two dense ceramic components together (e.g., joining a first dense ceramic component to a second dense ceramic component, joining a second dense ceramic component to a third dense ceramic component, etc.). The resulting single ceramic component has a unified structure in which the integrated parts are inseparable and bonded to one another to form a continuous component. Thus, such a single ceramic component is different from a bonded component that includes separate sub-components that have been joined together but remain distinct, where the sub-components are separable (i.e., the parts can be re-separated). Thus, a single component can include a generally substantially continuous mass of material or can include multiple parts that are inseparably bonded to one another. In any case, the various parts forming the single ceramic component are integrated to one another such that the single component is a single piece with inseparable parts. Thus, the resulting single ceramic component can be used as a single component while being formed in a process that allows for easier formation of more complex shapes (e.g., without the need for complex lamination processes).

[0019] Reference is made to Figure 1 and Figure 2 A first dense ceramic component 100 and a second dense ceramic component 102 are generally shown positioned adjacent to one another with a braze reactant layer 104 therebetween. As shown, a first contact surface 101 of the first dense ceramic component is positioned adjacent to a second contact surface 103 of the second dense ceramic component. The first contact surface 101 and the second contact surface 103 form an entire contact area 106 between the first dense ceramic component 100 and the second dense ceramic component 102. Although two dense ceramic components (100, 102) are shown, it should be understood that any number of dense ceramic components can be used with the braze reactant layer 104 positioned within each contact area 106 therebetween.

[0020] In one particular embodiment, the dense ceramic components (100, 102) are ceramic components (e.g., silicon carbide-based ceramics, such as reaction-bonded silicon carbide ceramics) and / or ceramic matrix components (“CMCs”) that have been fully formed via melt infiltration through densification, as described below. In one embodiment, at least one of the dense ceramic components (100, 102) contains 1% or more free silicon or free silicon alloy (e.g., 1% to 30% by volume of free silicon or free silicon alloy).

[0021] In one embodiment, a combination of different types of dense ceramic components (100, 102) can be joined together. For example, a first dense ceramic component (100) can include free silicon or a free silicon alloy (e.g., reaction bonded silicon carbide or a ceramic matrix composite fabricated via silicon melt infiltration) and be joined to a second dense ceramic component (102) that also includes free silicon or a free silicon alloy (e.g., reaction bonded silicon carbide or a ceramic matrix composite fabricated via silicon melt infiltration). In another embodiment, a first dense ceramic component (100) includes free silicon or a free silicon alloy (e.g., reaction bonded silicon carbide or a ceramic matrix composite fabricated via silicon melt infiltration) and is joined to a second dense ceramic component (102) that does not include any free silicon or a free silicon alloy (e.g., a CMC fabricated by chemical vapor infiltration (CVI), polymer impregnation and pyrolysis (PIP), sintered silicon carbide, hot pressed silicon carbide, silicon nitride, boron carbide, or a combination of methods or materials).

[0022] As used herein, a ceramic matrix composite or "CMC" refers to a class of materials that include a reinforcing material (e.g., reinforcing fibers) surrounded by a ceramic matrix phase. Typically, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of matrix materials for CMCs can include, but are not limited to, non-oxide silicon-based materials (e.g., silicon, silicon alloys, silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (AI2O3), silicon dioxide (SiO2), aluminosilicates, or mixtures thereof), or mixtures thereof. Optionally, ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) along with inorganic fillers in the form of a matrix filler (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite) can also be included within the CMC matrix.

[0023] Some examples of reinforcing fibers for CMCs can include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxide carbon-based materials (e.g., carbon), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (AI2O3), silicon dioxide (SiO2), aluminosilicates (such as mullite), or mixtures thereof), or mixtures thereof.

[0024] Generally, specific CMCs can be referred to by their combination of fiber type / matrix type. For example, C / SiC is carbon fiber reinforced silicon carbide, SiC / SiC is silicon carbide fiber reinforced silicon carbide, SiC / SiN is silicon carbide fiber reinforced silicon nitride, SiC / SiC-SiN is silicon carbide fiber reinforced silicon carbide / silicon nitride matrix hybrid, and the like. In other examples, CMCs can include a matrix and reinforcing fibers that comprise oxide-based materials such as alumina (AI2O3), silica (SiO2), aluminosilicates, and mixtures thereof. Aluminosilicates can include crystalline materials (e.g., mullite (3AI2O32SiO2)), as well as glassy aluminosilicates.

[0025] In certain embodiments, the reinforcing fibers can be bundled and / or coated prior to being included in the matrix. For example, the fiber bundles can be formed into reinforcing tapes, such as unidirectional reinforcing tapes. Multiple tapes can be laid up together to form a preform component. The fiber bundles can be impregnated with a slurry composition prior to forming the preform or after forming the preform. The preform can then be heat treated (e.g., cured or burned out) to produce a high char residue in the preform, and subsequently heat chemically treated (e.g., infiltrated with a silicon melt) to result in a dense ceramic component formed from a CMC material having a desired chemical composition.

[0026] Such materials, along with certain monolithic ceramics (i.e., ceramic materials without reinforcing materials), are particularly suitable for use in higher temperature applications. Further, these ceramic materials are lighter in weight compared to superalloys, yet are able to provide strength and durability to components made therefrom. As such, there is currently consideration for using such materials for many gas turbine components used in the higher temperature sections of a gas turbine engine, such as airfoils (e.g., blades and vanes), combustors, shrouds, and the like, which would benefit from the lighter weight and higher temperature capability that these materials can provide.

[0027] As described, the braze reactant layer 104 is positioned in the contact area 106 between the first dense ceramic component 100 and the second dense ceramic component 102. For example, the braze reactant layer 104 can be applied to either or both of the first contact surface 101 of the first dense ceramic component 100 and the second contact surface 103 of the second dense ceramic component 102. In one embodiment, the braze reactant layer 104 is positioned between the entire contact area 106 defined between the first dense ceramic component 100 and the second dense ceramic component 102 such that there is no gap therebetween. Thus, ceramic material, as well as metal and / or intermetallic material, can be formed throughout the contact area 106. However, this need not be the case depending on the desired final profile or contour.

[0028] The braze reactant layer 104 serves as a precursor to the ceramic layer formed during the joining process. In one embodiment, the braze reactant layer 104 can include ceramic precursor compounds, braze filler, binder, filler, pore-forming compounds, shrinkage control agents, and / or liquid carriers, among other optional additives.

[0029] Generally, the ceramic precursor compounds can react with the infiltrating composition. For example, the ceramic precursor compounds can include a carbon source material, such as carbon or carbon-forming resin in the form of a slurry, paste, or tape. Such carbon source materials can react with molten silicon or silicon alloy to form silicon carbide. Examples of carbon source materials include, but are not limited to, carbon black or organic material that produces carbon after pyrolytic heat treatment, a preceramic polymer, graphite powder, graphite flake, chopped carbon fiber, or mixtures thereof. Organic materials that can produce carbon after heat treatment (e.g., pyrolytic heat treatment) can include carbon-forming resins (e.g., including phenolic resins, furan or furan compounds, partially polymerized resins derived therefrom, polyarylynes, petroleum-tar based resins, and coal-tar based resins) and organic materials (e.g., wood, leaves, etc.). For example, the microstructure of wood is a porous composite microstructure, and this microstructure can be preserved after pyrolysis and conversion to silicon carbide by silicon melt infiltration, resulting in a joint having an engineered microstructure (honeycomb composite microstructure), which can be beneficial for mechanical properties. The preceramic polymer can include, but is not limited to, polycarbosilane, polycarbosilazane, polymethylsilane, polyborosilazane, polymethylvinylsilane, polysilylethylene, polytitancarbosilane, polymeric hydrosilazane, polymethylsiloxane, polyphenylsilasiloxane. The preceramic polymer produces a ceramic material after heat treatment that can help improve the mechanical properties of the joint.

[0030] In other embodiments, the ceramic precursor compounds can include silicide-forming precursors, such as metals including, but not limited to, Mo, W, Ti, Zr, or mixtures thereof.

[0031] In certain embodiments, the braze reactant layer 104 can also include a braze filler. For example, the braze filler can be ceramic or glass particles having substantially the same composition as the resulting ceramic material, such as non-oxide silicon-based material (e.g., silicon carbide, silicon nitride, or mixtures thereof) particles, oxide ceramic (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (AI2O3), silicon dioxide (SiO2), aluminosilicate, or mixtures thereof), or mixtures thereof. The braze filler can be present in the braze reactant layer up to 80 vol% relative to the carbon source material, such as 0.1% to 80% (e.g., 10-50 vol%) relative to the carbon source material. For example, the braze reactant layer can include 63 vol% carbon and 37 vol% SiC, as well as porosity, after pyrolysis.

[0032] When present, the braze filler can be a material that can be wetted by molten silicon or silicon alloy during the densification process. Such a braze filler can include an inorganic filler or mixture of inorganic fillers (e.g., ceramic materials, metallic materials, or mixtures thereof). The braze filler can be in powder form, but other morphologies are possible. In one embodiment, the braze filler includes a plurality of particles having a median diameter of less than 10 microns. In certain embodiments, the median diameter is less than 5 microns, and in particular embodiments, less than 1 micron. Finer particle sizes allow for higher surface area, better reactivity, and finer inter-particle porosity, all of which can be desirable in a system where it is intended that at least some of the particles react with the infiltrant during processing. In other embodiments, the inorganic filler has different sizes (a multimodal particle size distribution) and morphologies in order to tailor the porosity to minimize residual infiltrant, such as free silicon or free silicon alloy content, in the joint after the braze cycle.

[0033] In certain embodiments, the braze filler includes an inorganic filler or a mixture of inorganic fillers. When present, the inorganic filler can provide a framework into which a penetrating composition (e.g., a liquid metal or metalloid) is introduced during subsequent processing, thereby supplying one or more materials that ultimately participate in reactions to form the solid composition of the processed material, and / or increasing the strength of the processed material. Examples of inorganic fillers can include, but are not limited to, ceramic materials and / or metallic materials. Suitable ceramic materials include, but are not limited to, carbides (e.g., silicon carbide, titanium carbide, zirconium carbide, tantalum carbide, molybdenum carbide, chromium carbide, niobium carbide, boron carbide, vanadium carbide, or mixtures thereof), borides (e.g., boron carbide, titanium diboride, zirconium diboride, calcium hexaboride, or mixtures thereof), silicides (e.g., SiB6, TiSi2, MoSi2, or mixtures thereof), oxides (e.g., aluminum oxide, silicon dioxide, zirconium oxide, magnesium oxide, aluminate, lanthanum oxide, mullite, zircon, titanium oxide (rutile, anatase), yttrium oxide, ytterbium oxide, praseodymium oxide, or mixtures thereof), nitrides (e.g., silicon nitride, titanium nitride, aluminum nitride, zirconium nitride, chromium nitride, niobium nitride, vanadium nitride, or mixtures thereof), or mixtures thereof. Suitable metallic materials include, but are not limited to, silicon and alloys thereof (e.g., Si-B alloys, Si-Ge alloys, Si-Ti alloys, Si-Y alloys, Si-Hf alloys, Si-Cr alloys, Si-Zr alloys, Si-Co alloys, or mixtures thereof), titanium and alloys thereof, cobalt and alloys thereof, zirconium and alloys thereof, vanadium and alloys thereof, niobium and alloys thereof, boron and alloys thereof, or mixtures thereof. In some embodiments, the metallic materials can be in particulate form and can act as a source of penetrant for the braze reactant layer itself, as they will melt at temperatures below or equal to the braze temperature, but in some cases, this embodiment can be less desirable than embodiments in which the braze reactant layer is substantially free of a source of penetrant. In fact, when the braze reactant layer acts as a source of penetrant, the melting of the components of the braze reactant layer will typically result in some shrinkage of the braze reactant layer, which can be detrimental to tight tolerance joint assemblies, or some porosity in the braze reactant layer, which can be detrimental to the mechanical properties and oxidation resistance of the joint.

[0034] In one embodiment, the braze reactant layer 104 is generally tacky prior to solidification, such that the braze reactant layer 104 adheres the first and second dense ceramic components 100, 102 prior to heating. In particular embodiments, this tackiness can be provided by a binder and / or a liquid vehicle. For example, the binder can facilitate cohesion of the braze reactant layer, and help temporarily maintain the dense ceramic components (100, 102) joined together prior to the braze cycle. Suitable binders include, but are not limited to, natural gums (e.g., xanthan gum, acacia gum), polysaccharides (e.g., refined starch, dextrin), lignin extracts (e.g., paper mill effluent), refined alginates (e.g., Na, NH4 alginate), cellulose ethers (e.g., methylcellulose, hydroxyethylcellulose, sodium carboxymethylcellulose), epoxy resins, polymeric alcohols (e.g., polyvinyl alcohol), polymeric butyral (e.g., polyvinyl butyral), acrylic resins (e.g., polymethyl methacrylate), glycols (e.g., polyethylene glycol), waxes (e.g., paraffin wax, wax emulsions, microcrystalline wax), soluble silicates (e.g., sodium silicate), organosilicates (e.g., ethyl silicate), soluble phosphates (e.g., alkaline phosphates), microcrystalline cellulose, clays (e.g., bentonite, kaolin), soluble aluminates (e.g., soluble aluminate), or combinations thereof.

[0035] When present, the reactive filler can react with silicon or with gases present during the reaction process, such as gases of (e.g., CO, CO2, SiO, N2, NH3, H2), to form new compounds and / or react with the metal braze itself during heat treatment. Some examples of reactive fillers include, but are not limited to: C, Ti, V, Cr, Zr, Nb, Ta, Mo, W, Al, B, Si, MoSi2, CrSi2, TiSi2, or mixtures thereof. The reaction of the reactive filler during heat treatment results in a volume expansion, which can be beneficial to reduce porosity or free silicon or free silicon alloy present in the joint after the braze cycle. Reducing porosity in the joint can be beneficial to mechanical properties, and reducing residual penetrant (e.g., free silicon or free silicon alloy) in the joint can be beneficial to the thermo-mechanical properties of the joint.

[0036] One or more liquid vehicles can be used to apply the braze reactant layer 104. The liquid vehicle is generally volatile during processing, and can be selected to partially or completely dissolve one or more organic components of the formulation (e.g., binder). In some embodiments, the liquid vehicle comprises water or a water-based solvent. In some embodiments, the liquid vehicle comprises an organic liquid. The liquid vehicle can be present in the formulation in a range of 5 wt% to 65 wt% based on wet weight, but can vary as needed, in part depending on a number of factors including the desired flow characteristics and shrinkage behavior of the resulting formulation.

[0037] In some embodiments, the brazing reactant layer further includes a pore former disposed in the liquid carrier. While the processes described herein naturally provide a porous structure due to the removal of the liquid carrier and the mass reduction achieved during pyrolysis, the formation of pores can be desirably increased through the use of a pore former. In one embodiment, the pore former is a solid, soluble in the carrier, with a lower vapor pressure than the carrier to allow the pore former to remain as a residue as the carrier volatilizes. The pore former can be removed, for example, by burning off after the carrier is removed at a higher temperature during the pyrolysis step. In some embodiments, the pore former is an organic material, although it has a lower carbon yield than the binder. Examples of materials suitable for use as a pore former include polyvinyl butyral (PVB) resin, acrylic acid, acetate, and cellulose. The concentration of the pore former can be up to 15 wt% of the brazing reactant layer, based on the dry weight of the brazing reactant layer prior to brazing, and in certain embodiments, the pore former is present in a concentration of 2 wt% to 10 wt%, based on the dry weight of the brazing reactant layer prior to brazing. The porosity content of the brazing reactant layer after pyrolysis is in the range of 25 vol% to 70 vol% (e.g., 30 vol% to 55 vol%).

[0038] In some embodiments, the brazing reactant layer also includes a shrinkage control agent that provides a degree of rigidity to the formulation as it is processed. In particular, the mass loss associated with the volatilization of the liquid carrier and the conversion of the binder to carbon creates a driving force to shrink the dimensions of the remaining material. Excessive shrinkage can result in undesirable cracking within the product material. The shrinkage control agent then provides mechanical support to mitigate the shrinkage tendency. The shrinkage control agent can be in any form suitable to provide the described function; examples include particulates and fibers. The size of the agent is selected so that shrinkage is controlled while maintaining desirable flow characteristics, and so that the shrinkage control agent does not reduce the ability to densify with a liquid metalloids infiltrant. In one embodiment, the aspect ratio of the fibrous shrinkage control agent is in the range of 3 to 30. The aspect ratio determines in part the amount of shrinkage control agent needed, the degree of entanglement of the shrinkage control agent with itself, and the tendency of the shrinkage control agent to form a preferred arrangement during application. The median fiber length of the fibers making up the shrinkage control agent can be in the range of 75 to 250 pm, and the median diameter can be in the range of 5 to 15 pm. In embodiments where the shrinkage control agent is in the form of particulates, such as ceramic particulates, including, for example, silicon carbide particulates with a median size of at least 10 pm. The particulates can be used in a concentration up to 60 wt%, based on the dry weight of the brazing reactant layer, while the fibers can be used in an amount up to 20 wt% of the formulation.

[0039] In one embodiment, a shrinkage control agent comprising a carbon-containing filamentary material, such as chopped or milled carbon fiber, can be added to the formulation. In one embodiment, the milled carbon fiber is used at a concentration ranging from 1 wt% to 5 wt% based on the dry weight of the braze reactant layer prior to brazing. The carbon-containing filamentary material can be consumed in large amounts during infiltration with molten silicon due to reaction with silicon to form silicon carbide, but can not be completely consumed. Any residual amount of carbon that remains is believed to be sufficiently small as to not have an impact on the mechanical or thermal stability or oxidation resistance of the product formed after processing. Other compatible materials can be envisioned for use as the material of the shrinkage control agent in addition to or in place of carbon, such as silicon carbide particles or fibers. Polymeric fibers (e.g., nylon, cellulose, polyethylene, etc.) can also be used as the shrinkage control agent, provided that such materials have the necessary mechanical and thermochemical properties.

[0040] In certain embodiments, other additives are applied to the braze reactant layer. For example, where it is desired that the braze reactant layer behave like a thick paste or exhibit flexibility, such as in the case of applying the braze reactant layer via tape, a plasticizer can optionally be added to the braze reactant layer. Examples of plasticizers include triethylene glycol bis(2-ethylhexanoate) (e.g., available via Solutia, Inc. under the trade name SOLUSOLV), dibasic esters, glycols, and phthalates. The plasticizer can be used at a concentration up to 15 wt% based on the dry weight of the braze reactant layer, and in particular embodiments, is present in a range from 2 wt% to 6 wt%. Further, a dispersant, typically a surfactant selected for compatibility with the vehicle, is used in some embodiments to improve the separation of solids (e.g., ceramic filler particles) within the formulation, thereby reducing agglomeration. Examples of dispersants are polyethyleneimine, polyammonium methacrylate, sodium methacrylate, and fish oil. The dispersant can be used in the braze reactant layer at a concentration up to 3 wt% of the dry particles based on the dry weight of the braze reactant layer prior to brazing, and in some embodiments, the concentration is in a range from 0.1 wt% of the dry particles to 3 wt% of the dry particles.

[0041] In some embodiments, the method includes creating a braze reactant formulation that is applied to one or both of the contact surfaces (101, 103) of the dense ceramic part (100, 102). The braze reactant formulation can be applied on multiple surfaces and / or as multiple layers to the contact surfaces (101, 103), for example. Although shown as substantially planar contact surfaces (101, 103), the contact surfaces (101, 103) can be non-planar and can define multiple surfaces, such as in a cavity.

[0042] Forming the braze reactant formulation can include combining the ceramic precursor compound, braze filler, binder, reactive filler, pore-forming compound, shrinkage control agent, and / or liquid carrier, as well as other optional additives, together and mixing for a period of time to dissolve all soluble materials in the carrier, thereby de-agglomerating any agglomerates, and dispersing the filler particles. Mixing herein and elsewhere in the process involves the use of shear forces, tensile forces, compressive forces, ultrasonic energy, electromagnetic energy, thermal energy, or a combination comprising at least one of the foregoing force or energy forms, and can be carried out in a processing apparatus in which the foregoing force or energy forms are applied by a single screw, multiple screws, intermeshing co-rotating or counter-rotating screws, non-intermeshing co-rotating or counter-rotating screws, reciprocating screws, pinned screws, screened screws, pinned barrels, rollers, plungers, helical rotors, or a combination comprising at least one of the foregoing types of processing apparatuses. Mixing involving the foregoing forces can be carried out in a machine such as a single screw or multiple screw extruder, a Buss kneader, a Henschel, helicones, a Ross mixer, a Banbury, a roll mill, a ball mill, a paint shaker, a planetary centrifugal mixer, or the like, or a combination comprising at least one of the foregoing machines.

[0043] For example, the braze reactant layer 104 can be applied to a thickness sufficient to adhere the first and second dense ceramic components 100, 102 for further processing. In particular embodiments, for example, the braze reactant layer 104 can have a thickness of 10 micrometers (pm) to 2 millimeters (mm).

[0044] In one embodiment, a packaging material 108 can be positioned around at least a portion of the first and second dense ceramic components 100, 102. In particular embodiments, for example, the packaging material 108 can be a foil, a paper, a polymer film, a ceramic, a glass, or a combination comprising at least one of the foregoing materials. Figure 1 and Figure 2 In the illustrated embodiment, the first and second dense ceramic components 100, 102 are completely encased within the packaging material 108, such that their respective outer surfaces 105 substantially entirely contact the packaging material 108.

[0045] The packaging material 108 generally includes a material from the dense ceramic components that has a high vapor pressure under the processing conditions, such as a silicon-containing material (e.g., silicon, a silicon alloy, or a mixture thereof), which can inhibit the formation of porosity in the dense ceramic components (100, 102) during the heat treatment process. That is, the packaging material 108 is applied around the first and second dense ceramic components 100, 102 to provide a desired environment during the penetration and densification of the braze reactant layer 104.

[0046] In one embodiment, the infiltrating composition of the packaging material 108 has a composition of a silicon-containing material such that, when heated during the brazing cycle, the gas generates a local high vapor pressure of silicon at or near the outer surface 105 of the first and second dense ceramic components 100, 102 with the gas inhibiting the loss of silicon from the first or second dense ceramic components 100, 102 (and the associated formation of porosity). For example, in embodiments where the dense ceramic component is a melt-infiltrated CMC, the silicon-containing material (e.g., Si metal, silicon alloy, etc.) can form a silicon-rich crust during infiltration and densification with a local high silicon vapor pressure. Without being bound by any particular theory, it is believed that the silicon-containing material outside but near the outer surface 105 prevents the volatilization of silicon from the surface of the composite 105 near the packaging material 108, which volatilization would cause capillary action to draw liquid silicon from within the ceramic component to the surface and would cause the formation of porosity within the dense ceramic component. Thus, the packaging material 108 facilitates a higher vapor pressure of the constituent (e.g., silicon) to inhibit the formation of porosity in the dense ceramic components 100, 102.

[0047] Thus, to join silicon-containing ceramics, the packaging material 108 generally includes a silicon-containing material (e.g., silicon, silicon alloy, or mixtures thereof) that can inhibit the formation of porosity in the dense ceramic components (100, 102) during the heat treatment process. For example, the silicon-containing material can include, but is not limited to, pure silicon, silicon alloys (e.g., Si-B alloys, Si-Ge alloys, Si-Ti alloys, Si-Y alloys, Si-Hf alloys, Si-Cr alloys, Si-Zr alloys, Si-Co alloys, or mixtures thereof), mixtures of constituents (e.g., Si and B4C, Si and B, Si and SiB6, Si and MoSi2, Si and TiSi2, Si and Ge, etc.), silicon nitride, or mixtures thereof.

[0048] The packaging material 108 can also include carbon materials (e.g., carbon black powder, graphite powder, graphite flakes, chopped carbon fibers, etc.) and / or inorganic particles, such as carbides (e.g., silicon carbide, titanium carbide, zirconium carbide, tantalum carbide, molybdenum carbide, chromium carbide, niobium carbide, boron carbide, vanadium carbide, etc.), borides (e.g., boron carbide, boron nitride, titanium diboride, zirconium diboride, calcium hexaboride, etc.), silicides (e.g., SiB6, TiSi2, MoSi2, etc.), oxides (e.g., aluminum oxide, zirconium oxide, magnesium oxide, aluminate, lanthanum oxide, mullite, zircon, titanium oxide (rutile, anatase), yttrium oxide, ytterbium oxide, praseodymium oxide, etc.), nitrides (e.g., silicon nitride, titanium nitride, aluminum nitride, zirconium nitride, chromium nitride, niobium nitride, vanadium nitride, etc.), metallic materials (e.g., titanium and alloys thereof, cobalt and alloys thereof, zirconium and alloys thereof, vanadium and alloys thereof, niobium and alloys thereof, boron and alloys thereof, etc.), or mixtures thereof.

[0049] The packaging material 108 can also include materials such as binders, dispersants, and the like (e.g., as described above). For example, a binder can promote cohesion of the packaging material 108 and help temporarily hold the packaging material 108 close to the dense ceramic components (100, 102) during the brazing cycle. Suitable binders include, but are not limited to, natural gums (e.g., xanthan gum, acacia gum), polysaccharides (e.g., refined starch, dextrin), lignin extracts (e.g., paper mill effluent), refined alginates (e.g., Na, NH4 alginate), cellulose ethers (e.g., methylcellulose, hydroxyethylcellulose, sodium carboxymethylcellulose), polymeric alcohols (e.g., polyvinyl alcohol), polymeric butyral (e.g., polyvinyl butyral), acrylic resins (e.g., polymethyl methacrylate), glycols (e.g., polyethylene glycol), waxes (e.g., paraffin wax, wax emulsions, microcrystalline wax), soluble silicates (e.g., sodium silicate), organosilicates (e.g., ethyl silicate), soluble phosphates (e.g., alkaline phosphates), microcrystalline cellulose, clays (e.g., bentonite, kaolin), soluble aluminates (e.g., soluble aluminates), or combinations thereof.

[0050] The packaging material can be applied by techniques such as casting, slurry spraying, brushing, manual application with a trowel, rubber squeegee, hand applied techniques.

[0051] The at least one infiltrant source 109 is also positioned in fluid communication with the brazing reactant layer 104 such that the infiltrating fluid can flow from the at least one infiltrant source 109 directly into the brazing reactant layer 104 or indirectly into the brazing reactant layer 104 via a wick (e.g., wick 117 discussed below). The infiltrant source includes a silicon-containing material, which can include, but is not limited to, pure silicon, silicon alloys (e.g., Si-B alloys, Si-Ge alloys, Si-Ti alloys, Si-Y alloys, Si-Hf alloys, Si-Cr alloys, Si-Zr alloys, Si-Co alloys, or mixtures thereof), mixtures of components (e.g., Si and B4C, Si and B, Si and SiB6, Si and MoSi2, Si and TiSi2, Si and Ge, etc.), silicon nitride, or mixtures thereof.

[0052] In some embodiments, the infiltrant source will react with some components of the brazing reactant layer to form new compounds that will enhance the properties of the joint. For example, the infiltrant source can include a silicon alloy that will react with carbon from the brazing reactant layer to form silicon carbide. Silicon carbide can be beneficial to the thermal mechanical properties of the joint because it is a material with good thermal mechanical properties.

[0053] Generally, the at least one infiltrant source 109 includes an infiltrant composition (e.g., silicon) that can react with the carbon source material of the braze reactant layer 104 to form a ceramic material (e.g., a silicon carbide material). In certain embodiments, multiple infiltrant sources 109 can be positioned in fluid communication with the braze reactant layer 104. Each of the at least one infiltrant source 109 can have a composition that is independent of the other infiltrant sources 109, which allows for customization and / or increased control of the local infiltrant composition within the braze reactant layer 104.

[0054] In one embodiment, the packaging material 108 can also function as and / or include the at least one infiltrant source 109, such that an infiltrant fluid can flow from the packaging material 108 into the braze reactant layer 104 to react with the carbon source material therein to form a ceramic material within the contact region 106. In one embodiment, the at least one infiltrant source 109 includes a silicon-containing material (e.g., silicon, a silicon alloy, or a mixture thereof) that melts at or below the processing temperature, such that Si liquid flows into the braze reactant layer 104 and reacts with C from the carbon source material to form SiC as the ceramic material. Referring to Figure 3 , the single ceramic part 110 is shown as having a dense ceramic material 112 that effectively integrates the first dense ceramic part 100 and the second dense ceramic part 102. As used herein, the terms “integral” or “integrated” or “single” describe a unitary structure formed of continuous material or groups of materials, without seams, connecting joints, etc.

[0055] Referring to Figure 1 and Figure 2 In certain embodiments, the packaging material 108 can have a packaging composition that is different from the infiltrant composition. Thus, the melting temperature of the packaging material 108 can have a different melting temperature than the at least one infiltrant source 109 used to densify the first dense ceramic part 100 and the second dense part 102. For example, a SiB alloy (e.g., a SiB eutectic alloy) can be the infiltrant material used to densify the first dense ceramic part 100 and the second dense part 102, and the at least one infiltrant source 109 within the packaging material 108 can be a silicon metal having a higher melting point than the SiB alloy.

[0056] In addition to the silicon-containing material, the packaging material 108 can also include a release agent, such as boron nitride (BN). When present, the release agent can help to decouple the resulting package after heat treatment to open the dense single ceramic part 110 Figure 3 ) after heat treatment.

[0057] As needed, packaging material 108 may also contain other materials, such as adhesives, curing agents, solvents, or mixtures thereof. For example, adhesives or curing agents may be added to packaging material 108 to promote its cohesion and help temporarily hold parts in place before and during heat treatment cycles. The amount of any liquid (e.g., water, aqueous liquids, or organic liquids such as isopropanol) can be controlled within packaging material 108 to achieve the desired consistency compatible with the application processing.

[0058] Figure 1 The packaging material 108 is shown to be in the form of a powder-containing material (e.g., powder, paste, etc.) surrounding the outer surfaces 105 of the first dense ceramic component 100 and the second dense ceramic component 102. In alternative embodiments, such as Figure 2 As shown, the packaging material 108 may be a coating applied to the outer surfaces 105 of the first dense ceramic component 100 and the second dense ceramic component 102. The coating of the packaging material 108 can be applied or deposited using conventional methods known to those skilled in the art. Such conventional methods typically include, but are not limited to, plasma spraying; high-speed plasma spraying; low-pressure plasma spraying; solution plasma spraying; suspension plasma spraying; high-velocity oxygen flame (HVOF); electron beam physical vapor deposition (EBPVD); sol-gel; sputtering; slurry treatments such as dipping, spraying, rolling, plastering, painting, and applying putty-like pastes; and combinations of these methods. In an exemplary embodiment, the packaging material 108 may be deposited via a slurry treatment (e.g., dipping, spraying, rolling, or painting). In another exemplary embodiment, to help control the amount and thickness of the deposited packaging material 108, a vibrating die or tool may be used to deposit the packaging material 108 as a shear-thinning paste. Figure 1 and Figure 2 In both embodiments, the packaging material 108 is positioned adjacent to the outer surface 105 and can be processed... Figure 3 The single ceramic component 110 was subsequently removed.

[0059] Regardless of whether at least one permeation source 109 is present within the packaging material 108, at least one permeation source 109 may also include a braze fillet 114, the braze fillet 114 optionally positioned adjacent to, for example, Figure 1 and 2At least one outer edge 116 of the braze reactant layer 104 between the first and second dense ceramic components 100, 102 is shown. In one particular embodiment, the braze fillet 114 includes a permeation composition, such as a permeation composition having substantially the same composition as the permeation composition of the packaging material 108 (when present). In another embodiment, the braze fillet 114 includes a permeation composition that is different than the permeation composition of the packaging material 108. Generally, the braze fillet 114 can be positioned along the at least one outer edge 116 of the braze reactant layer 104. Such a localized braze fillet 114 can act as a source of a permeation composition to react with the braze reactant layer 114 and form a joint. Thus, the localized braze fillet 114 can ensure sufficient reaction with the braze reactant layer 104 to form the resulting dense ceramic material 112 along the at least one outer edge 116.

[0060] In particular embodiments, the braze fillet 114 includes silicon, a silicon alloy, or a mixture thereof. For example, the braze fillet 114 can include 80% or more silicon and / or a silicon alloy by weight (e.g., 80% to 100% by weight). In one particular embodiment, a boron-containing component can be included within the braze fillet 114, such as boron, boron carbide, and / or boron silicide. For example, the braze fillet can include 2% to 20% boron carbide (e.g., B4C) by weight and 80% to 98% silicon by weight. In another embodiment, the braze fillet includes a silicon boron pre-alloy. For example, the braze fillet 114 can be formed from a mixture of silicon powder and boron carbide powder. Thus, the braze fillet 114 facilitates silicon permeation of the braze reactant layer 104. In this way, Si reacts with C from the carbon source material to form SiC as the dense ceramic material 112 Figure 3 ), as discussed above.

[0061] Referring to Figure 1 and Figure 2Whether or not the packaging material 108 includes at least one source of permeation 109, or if the brazing fillet 114 is present, the at least one source of permeation 109 can also include a puck 115, which can be optionally positioned in fluid communication with the brazing reactant layer 104 via a wick or wick line 117 (e.g., a carbon line). The puck 115 can include a silicon-containing material (e.g., silicon metal, silicon alloy, etc.) that melts at or below the brazing temperature. In addition to the silicon-containing material, the puck 115 can also include other constituents (e.g., a boron-containing material). The wick 117 transports the molten puck material (e.g., silicon) to the brazing reactant layer 104 between the first and second dense ceramic components. As shown, in particular embodiments, the puck 115 can be positioned outside of the packaging material 108. Generally, the wick 117 is positioned adjacent to each of the puck 115 and the brazing reactant layer 104 so as to carry the molten permeation composition from the puck 115 to the brazing reactant layer via the wick 117. The wick 117 can be a carbon fiber sheet, such as a nonwoven web, a woven web, a felt, a carbon line, or a carbon line.

[0062] Prior to heating to the brazing temperature, the packaging material 108, the first dense ceramic component 100, and the second dense ceramic component 102 can optionally be wrapped with a carbon sheet 118. For example, the carbon sheet 118 can be a woven sheet, a nonwoven sheet, a felt sheet, or a film of carbon-containing material. In one embodiment, the carbon sheet 118 can be a carbon felt, which can be impregnated with a boron-containing material (e.g., boron carbide, boron nitride, etc.). When present, the carbon sheet 118 can help ensure that the packaging material 108 does not fall off and remain around the brazing fillet 114 (when present), the first dense ceramic component 100, and the second dense ceramic component 102. During heating, the permeation composition can react with the carbon sheet 118 to form a ceramic material within the carbon sheet 118, which is then removed from around the first and second dense ceramic components 100, 102 and the packaging material 108 is removed from the outer surface 105 of the single ceramic component 110. Figure 3 ).

[0063] Optionally, a mask 120 can be applied to a portion of the outer surface 105 of the first and / or second dense ceramic components 100, 102 to limit the bonding of the packaging material 108. More specifically, the mask 120 helps to block or prevent the packaging material 108 from adhering to areas of the outer surface 105 that are sensitive to the build-up of components of the packaging material 108, such as silicon, during brazing. For example, the areas of the outer surface 105 can be one or more machined features (e.g., cooling holes, attachment or mounting holes, slots, and / or sealing surfaces), features having critical dimensions (e.g., machined features having small tolerances), or areas that are difficult to remove build-up of unwanted material (e.g., unwanted or accumulated silicon, etc.). In this manner, the mask 120 can be considered an outer surface pre-treatment. It should be understood that the mask 120 is selectively applied to the outer surface 105, and one or more portions of the outer surface 105 can remain uncoated or untreated with the mask 120. In some embodiments, the mask 120 is not needed or can be omitted, and thus, no mask 120 is applied to the outer surface 105 prior to the application of the packaging material 108. In example embodiments, the mask 120 is a non-organic release agent capable of withstanding temperatures of at least 1000 °C (e.g., temperatures in the range of 1000 °C to about 1600 °C), such as boron nitride (BN) or similar release agent that limits the bonding of the packaging material 108. In one embodiment, the mask can be a non-silicon wetting compound that is applied to the surface of the ceramic component to mask the silicon. An example of a non-wetting ceramic composition is boron nitride. The boron nitride can be applied to the surface of the ceramic component as a ceramic suspension as a mask.

[0064] The packaging material 108, the first dense ceramic component 100, and the second dense ceramic component 102 are then heated to a brazing temperature that is equal to or greater than the melting point of at least one component of the at least one infiltrating source 109. As a result, the component of the at least one infiltrating source 109 forms a liquid to infiltrate the brazing reactant layer 104 and react with the carbon source material, thereby forming a dense ceramic material 112 that joins the first dense ceramic component 100 and the second dense ceramic component 102 as a single ceramic component 110 as shown. Figure 3

[0065] In one embodiment, the ceramic material of the single ceramic component 110 includes the dense ceramic material 112 along the entire contact area 106 between the dense ceramic components 100, 102 (e.g., along the first contact surface 101 of the first dense ceramic component 100 and the second contact surface 103 of the second dense ceramic component 102). For example, the dense ceramic material 112 can have substantially the same composition as the ceramic material of the dense ceramic components 100, 102, such that the resulting single ceramic component 110 includes a single ceramic material therein.

[0066] ​After heating and subsequent cooling, the packaging material 108 (along with optional carbon sheet 118 and optional mask 120) is removed from the outer surface 105 to reveal the resulting single ceramic component 110. Figure 3 ).

[0067] The single ceramic component 110 is particularly suitable for use as components in high-temperature environments, such as those found in gas turbine engines, including combustor components, turbine blades, shrouds, nozzles, heat shields, and impellers. Specifically, the single ceramic component 110 can be a component positioned within the hot gas flow path of the gas turbine. The term "gas turbine engine" refers to an engine that has a turbine as its power source, in whole or in part. The term "turbine" or "turbomachinery" refers to a machine that includes one or more compressors, a heating section (e.g., a combustion section), and one or more turbines that together generate torque output. Example gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, and hybrid electric versions of one or more of these engines.

[0068] Figure 4 This is a schematic cross-sectional view of a gas turbine engine according to an exemplary embodiment of the present disclosure. More specifically, for Figure 4 In one embodiment, the gas turbine engine is a high-bypass turbofan jet engine 10, referred to herein as "turbofan engine 10". Figure 4 As shown, the turbofan engine 10 defines an axial direction A (extending parallel to the longitudinal axis 12 provided for reference) and a radial direction R. Typically, the turbofan engine 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of the fan section 14. Although described below with reference to the turbofan engine 10, this disclosure is generally applicable to turbomachinery, including turbojet engines, turboprop engines, and turboshaft gas turbine engines, including industrial and marine gas turbine engines and auxiliary power units. This disclosure is also applicable to other high-temperature applications.

[0069] The depicted exemplary core turbine engine 16 generally includes a generally tubular casing 18 defining an annular inlet 20. The casing 18 surrounds, in a series flow relationship: a compressor section including a turbocharger or low-pressure (LP) compressor 22 and a high-pressure (HP) compressor 24; a combustion section 26; a turbine section including a high-pressure (HP) turbine 28 and a low-pressure (LP) turbine 30; and an exhaust nozzle section 32. A high-pressure (HP) spool or shaft 34 drivesly connects the HP turbine 28 to the HP compressor 24. A low-pressure (LP) spool or shaft 36 drivesly connects the LP turbine 30 to the LP compressor 22.

[0070] For the depicted embodiment, the fan section 14 includes a variable-pitch fan 38 having a plurality of fan blades 40 coupled to a disc 42 in a spaced apart manner. As depicted, the fan blades 40 extend outwardly from the disc 42 in a generally radial direction R. Each fan blade 40 is rotatable relative to the disc 42 about a pitch axis P by virtue of the fan blades 40 being operatively coupled to a suitable actuation member 44 that is configured to collectively and uniformly change the pitch of the fan blades 40. The fan blades 40, the disc 42, and the actuation member 44 are rotatable together about the longitudinal axis 12 by the LP shaft 36 across an optional power gear box 46. The power gear box 46 includes a plurality of gears for reducing the rotational speed of the LP shaft 36 to a more efficient rotational fan speed.

[0071] Still referring to Figure 4 the exemplary embodiment, the disc 42 is covered by a rotatable front nacelle 48 that is aerodynamically shaped to facilitate airflow through the plurality of fan blades 40. Additionally, the exemplary fan section 14 includes an annular fan case or outer nacelle 50 that circumferentially surrounds the fan 38 and / or at least a portion of the core turbine engine 16. It should be appreciated that the nacelle 50 can be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced apart outlet guide vanes 52. Moreover, a downstream section 54 of the nacelle 50 can extend over an outer portion of the core turbine engine 16 so as to define a bypass airflow passage 56 therebetween.

[0072] During operation of the turbofan engine 10, an amount of air 58 enters the turbofan engine 10 through an associated inlet 60 of the nacelle 50 and / or the fan section 14. As the amount of air 58 passes through the fan blades 40, a first portion of the air as indicated by arrows 62 is directed or channeled into the bypass airflow passage 56 and a second portion of the air as indicated by arrows 64 is directed or channeled into the LP compressor 22. The ratio between the first and second portions of air 62, 64 is commonly referred to as a bypass ratio. The second portion of air 64 then increases in pressure as it is channeled through the high pressure (HP) compressor 24 and into the combustion section 26 where it is mixed with fuel and combusted to provide combustion gases 66.

[0073] Combustion gas 66 is directed through HP turbine 28, where a portion of the thermal and / or kinetic energy from the combustion gas 66 is extracted via a sequential stage of HP turbine stator blades 68 connected to housing 18 and HP turbine rotor blades 70 connected to HP spool or shaft 34, thus rotating HP spool or shaft 34 to support the operation of HP compressor 24. Combustion gas 66 is then directed through LP turbine 30, where a second portion of the thermal and kinetic energy is extracted from the combustion gas 66 via a sequential stage of LP turbine stator blades 72 connected to housing 18 and LP turbine rotor blades 74 connected to LP spool or shaft 36, thus rotating LP spool or shaft 36 to support the operation of LP compressor 22 and / or the rotation of fan 38.

[0074] Combustion gas 66 is then directed through the injection exhaust nozzle section 32 of the core turbine engine 16 to provide propulsive thrust. Simultaneously, the pressure of the first portion of air 62 increases significantly as it is directed through the bypass airflow passage 56 before exiting from the fan nozzle exhaust section 76 of the turbofan engine 10, also providing propulsive thrust. The HP turbine 28, LP turbine 30, and injection exhaust nozzle section 32 at least partially define a hot gas path 78 for guiding combustion gas 66 through the core turbine engine 16.

[0075] As described above, a method for bonding a first dense ceramic component to a second dense ceramic component to form a single ceramic component is also generally provided. For example, Figure 5 A diagram illustrates an exemplary method 500 for joining two (or more) dense ceramic components together. At 502, a brazing reactant layer is positioned on at least two dense ceramic components (e.g., those described above). Figure 1 and Figure 2 In the contact area between the first dense ceramic component 100 and the second dense ceramic component 102, optionally, at 504, a brazing fillet is positioned adjacent to at least one outer edge of the brazing reactant layer, as described above. At 506, packaging material is positioned around at least two dense ceramic components. Optionally, at 508, the packaging material may be encased in a carbon sheet. At 510, the packaging material and the dense ceramic components are heated to a brazing temperature, typically higher than the melting point of the penetrating composition as described above. Thus, the penetrating composition (e.g., in the packaging material and / or the brazing fillet) penetrates the brazing reactant layer to react with the carbon source material therein and form a ceramic material that bonds the dense ceramic components into a single ceramic component. After heating, the single ceramic component can be cooled and the packaging material can be removed from the outer surface of the single ceramic component. Although not in Figure 5 As shown, a portion of the outer surface of one or more dense ceramic components can be masked before heating and before packaging materials are positioned around them.

[0076] As described above, the resulting single ceramic component has a uniform structure in which the integrated portions are inseparable and bonded to one another to form a continuous component. Thus, the resulting single ceramic component can be used as a single component while being formed in a process that allows for easier formation of more complex shapes (e.g., without the need for complex lamination processes). Thus, the single ceramic component can be formed from multiple dense ceramic components without creating additional defects in the single ceramic component because the resulting single ceramic component can be formed using the same or substantially similar infiltrant (e.g., Si-B) as used in melt infiltration, resulting in joint properties and qualities that are close to existing CMC matrices.

[0077] Further aspects are provided by the subject matter of the following clauses:

[0078] 1. A method of forming a single ceramic component, the method comprising: positioning a braze reactant layer in a contact region between a first dense ceramic component and a second dense ceramic component, wherein the braze reactant layer comprises a ceramic precursor compound; thereafter, positioning a packaging material around at least a portion of the first dense ceramic component or the second dense ceramic component, wherein the packaging material comprises a silicon-containing material; positioning at least one infiltration source in fluid communication with the braze reactant layer, wherein the at least one infiltration source comprises an infiltration composition; and thereafter, heating the at least one infiltration source, the packaging material, the first dense ceramic component, and the second dense ceramic component to a braze temperature equal to or greater than a melting point of at least one phase of the infiltration composition, such that the at least one phase of the infiltration composition melts and flows into the braze reactant layer and reacts with the ceramic precursor compound to form a ceramic material that joins the first dense ceramic component and the second dense ceramic component as a single ceramic component.

[0079] 2. The method of any preceding clause, wherein the ceramic precursor compound comprises a carbon source material.

[0080] 3. The method of any preceding clause, wherein the packaging material comprises the at least one infiltration source.

[0081] 4. The method of any preceding clause, wherein positioning the packaging material comprises completely surrounding the first dense ceramic component and the second dense ceramic component.

[0082] 5. The method of any preceding clause, wherein the infiltration composition comprises a mixture of silicon metal, a silicon alloy, or any combination thereof.

[0083] 6. The method of any preceding clause, wherein the packaging material further comprises a binder, a curing agent, a solvent, or a mixture of any combination thereof.

[0084] 7. The method of claim 1, wherein the packaging material is in the form of a powder- containing material.

[0085] 8. The method of any preceding clause, wherein positioning the packaging material comprises applying a coating on an outer surface of the first and second dense ceramic components.

[0086] 9. The method of any preceding clause, wherein the at least one infiltration source comprises a braze fillet positioned in fluid communication with the braze reactant layer.

[0087] 10. The method of any preceding clause, further comprising positioning the braze fillet proximate to at least one outer edge of the braze reactant layer between the first and second dense ceramic components prior to positioning the packaging material around at least a portion of the first and second dense ceramic components.

[0088] 11. The method of any preceding clause, wherein the braze fillet comprises a mixture of silicon metal, silicon alloy, or any combination thereof.

[0089] 12. The method of any preceding clause, wherein the at least one infiltration source comprises a puck positioned in fluid communication with the braze reactant layer.

[0090] 13. The method of any preceding clause, further comprising positioning a puck in fluid communication with the braze reactant layer, wherein the infiltration composition, when melted, flows from the puck to the braze reactant layer via a wick or wick wire.

[0091] 14. The method of any preceding clause, wherein the puck comprises a mixture of silicon metal, silicon alloy, or any combination thereof.

[0092] 15. The method of any preceding clause, further comprising wrapping the packaging material, the first and second dense ceramic components in a carbon sheet prior to heating the packaging material and after positioning the packaging material around at least a portion of the first and second dense ceramic components.

[0093] 16. The method of any preceding clause, further comprising cooling the single ceramic component after heating the packaging material to the braze temperature; and removing the carbon sheet from around the first and second dense ceramic components and the packaging material from an outer surface of the single ceramic component.

[0094] 17. The method of any preceding clause, wherein the braze reactant layer further comprises a braze filler.

[0095] 18. The method of any preceding clause, wherein the braze filler comprises inorganic particles.

[0096] 19. The method of any preceding clause, wherein positioning the braze reactant layer comprises positioning the braze reactant layer between the entire contact area defined between the first and second dense ceramic components.

[0097] 20. The method of any preceding clause, further comprising applying a mask to a portion of an outer surface of the first dense ceramic component, the second dense ceramic component, or both, prior to positioning the packaging material around at least a portion of the first and second dense ceramic components.

[0098] 21. A single ceramic component formed by the method of any preceding clause.

[0099] 22. A single ceramic component comprising a dense ceramic material between a first dense ceramic component and a second dense ceramic component.

[0100] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method of forming a single ceramic component, characterized by, The method comprises: positioning a braze reactant layer in a contact area between a first dense ceramic component and a second dense ceramic component, wherein the braze reactant layer comprises a ceramic precursor compound, and wherein at least one of the first dense ceramic component and the second dense ceramic component comprises free silicon or a free silicon alloy; thereafter, positioning a packaging material around at least a portion of the first dense ceramic component or the second dense ceramic component, wherein the packaging material comprises a silicon-containing material; positioning at least one infiltration source in fluid communication with the braze reactant layer, wherein the at least one infiltration source comprises an infiltration composition; and thereafter, heating the at least one infiltration source, the packaging material, the first dense ceramic component, and the second dense ceramic component to a braze temperature equal to or greater than a melting point of at least one phase of the infiltration composition, such that the at least one phase of the infiltration composition melts and flows into the braze reactant layer and reacts with the ceramic precursor compound to form a ceramic material that joins the first dense ceramic component and the second dense ceramic component as a single ceramic component.

2. The method of claim 1, wherein, wherein, the ceramic precursor compound comprises a carbon source material.

3. The method of claim 1, wherein, wherein, the packaging material comprises the at least one infiltration source.

4. The method of claim 1, wherein, wherein, positioning the packaging material comprises completely surrounding the first dense ceramic component and the second dense ceramic component.

5. The method of claim 1, wherein, wherein, the infiltration composition comprises a mixture of silicon metal, a silicon alloy, or any combination thereof.

6. The method of claim 1, wherein, wherein, the packaging material further comprises a binder, a curing agent, a solvent, or a mixture of any combination thereof.

7. The method of claim 1, wherein, wherein, the packaging material is in a form of a powder-containing material.

8. The method of claim 1, wherein, wherein, positioning the packaging material comprises applying a coating on an outer surface of the first dense ceramic component and the second dense ceramic component.

9. The method of claim 1, wherein, wherein, the at least one infiltration source comprises a braze fillet positioned in fluid communication with the braze reactant layer.

10. The method of claim 9, wherein, further comprising: positioning the braze fillet adjacent to at least one outer edge of the braze reactant layer between the first dense ceramic component and the second dense ceramic component prior to positioning the packaging material around at least a portion of the first dense ceramic component and the second dense ceramic component.

11. The method of claim 9, wherein, wherein, the braze fillet comprises a mixture of silicon metal, a silicon alloy, or any combination thereof.

12. The method of claim 1, wherein, wherein, the at least one infiltration source comprises a puck positioned in fluid communication with the braze reactant layer.

13. The method of claim 12, wherein, further comprising: positioning a puck in fluid communication with the braze reactant layer, wherein the infiltration composition, when melted, flows from the puck to the braze reactant layer via a wick or a wick wire.

14. The method of claim 12, wherein, wherein, the puck comprises a mixture of silicon metal, a silicon alloy, or any combination thereof.

15. The method of claim 1, wherein, further comprising: wrapping the packaging material, the first dense ceramic component, and the second dense ceramic component in a carbon sheet prior to heating the packaging material and after positioning the packaging material around at least a portion of the first dense ceramic component and the second dense ceramic component.

16. The method of claim 15, wherein, further comprising: cooling the single ceramic part after heating the packaging material to the brazing temperature; and removing the carbon sheet from around the first and second dense ceramic parts and removing the packaging material from an outer surface of the single ceramic part.

17. The method of claim 1, wherein, wherein, the brazing reactant layer further comprises a braze filler.

18. The method of claim 17, wherein, wherein, the braze filler comprises inorganic particles.

19. The method of claim 1, wherein, wherein, positioning the brazing reactant layer comprises positioning the brazing reactant layer between the entire contact area defined between the first and second dense ceramic parts.

20. The method of claim 1, wherein, further comprising: applying a mask to a portion of an outer surface of the first dense ceramic part, the second dense ceramic part, or both prior to positioning the packaging material around at least a portion of the first and second dense ceramic parts.

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