Method for producing high-temperature-resistant coating and structure

Abstract

To provide methods for forming ceramic-based materials, including coatings, three-dimensional (3D) objects, and ceramic composites thereof, having desirable properties such as high-temperature resistance and increased toughness.SOLUTION: A method for forming a ceramic-based material comprises: depositing a ceramic-precursor composition comprising nanoparticles having at least one dimension less than 100 nm and an aspect ratio of 1.5 or greater, and a carrier fluid on a surface of a substrate to form an as-deposited layer of the ceramic precursor composition; and sintering the as-deposited layer of the ceramic precursor composition at a sintering temperature to form a ceramic-based material.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] Ceramic materials are widely used in transportation, including aerospace, due to their high-temperature resistance and mechanical strength, corrosion resistance in both oxidizing and reducing environments, light weight, and low coefficient of thermal expansion. Aircraft and spacecraft components requiring these properties include engine parts, brakes, insulating tiles, leading edges and cones, and even cabin interior elements. Ceramic matrix composites, which combine ceramics with other materials such as carbon fiber, are also important because they offer high-temperature resistance (2910°F) and fracture toughness, a combination that is very difficult to achieve with single-component ceramics. Metal carbides are particularly important due to their light weight and multifunctional properties.

[0002] However, processing ceramic composites into coatings or other aircraft components is challenging. Initial steps typically involve chemical vapor deposition (CVD), precursor pyrolysis, reactive melt infiltration, slurry infiltration, and hot pressing. Annealing requires high-temperature treatment of the precursor at temperatures as high as 5430°F (3000°C) to sinter the constituent particles and fibers. Both the bulk part and the coating tend to deform during this process, and the components may also undergo undesirable phase changes. Summary of the Invention

[0003] A method is provided for forming ceramic-based materials, including coatings, three-dimensional (3D) objects, and ceramic composites thereof, that have desirable properties such as high-temperature resistance and enhanced toughness. However, compared to existing methods, the method employs significantly lower temperatures, which avoids problems such as distortion and delamination and allows for the use of a wider variety of substrates in creating ceramic-based materials.

[0004] In embodiment 1, a method for forming a ceramic-based material includes depositing a ceramic precursor composition on a surface of a substrate, the ceramic precursor composition including nanoparticles having at least one dimension less than 100 nm and an aspect ratio greater than or equal to 1.5 and a carrier fluid to form an as-deposited layer of the ceramic precursor composition; and sintering the as-deposited layer of the ceramic precursor composition at a sintering temperature to form the ceramic-based material.

[0005] Embodiment 2 is the method of embodiment 1, wherein the nanoparticles have at least one dimension in the range of 1 nm to 100 nm.

[0006] Embodiment 3 is the method of embodiment 2, wherein the nanoparticles have individual dimensions of less than 100 nm.

[0007] Embodiment 4 is the method of any one of embodiments 1 to 3, wherein the nanoparticles are nanoplatelets.

[0008] Embodiment 5 is the method of any one of embodiments 1 to 4, wherein the nanoparticles comprise a ceramic compound.

[0009] Embodiment 6 is the method of any one of embodiments 1 to 5, wherein the nanoparticles comprise WO3, ceria, hafnia, titania, or a combination thereof.

[0010] Embodiment 7 is the method of any one of embodiments 1 to 6, wherein the nanoparticles comprise compounds that form ceramic compounds during sintering.

[0011] Embodiment 8 is the method of any one of embodiments 1 to 7, wherein the nanoparticles are single crystalline.

[0012] Embodiment 9 is the method of any one of embodiments 1 to 8, wherein the carrier fluid is water, an organic solvent, or an ionic liquid.

[0013] Embodiment 10 is the method of any one of embodiments 1 to 8, wherein the carrier fluid is an inorganic ionic liquid.

[0014] Embodiment 11 is the method of any one of embodiments 1 to 8, wherein the carrier fluid is a polymer or a precursor thereof.

[0015] Embodiment 12 is the method of embodiment 11, wherein the polymer is an inorganic polymer or a precursor thereof.

[0016] Embodiment 13 is the method of any one of embodiments 1 to 12, wherein the deposition is carried out at a temperature less than 100° C.

[0017] Embodiment 14 is the method of embodiment 13, wherein the deposition is carried out at or below room temperature.

[0018] Embodiment 15 is the method of any one of embodiments 1 to 14, wherein the deposition is carried out using layer-by-layer deposition to provide an as-deposited multilayer structure comprising as-deposited layers of ceramic precursor composition.

[0019] Embodiment 16 is the method of any one of embodiments 1 to 15, wherein the sintering temperature is less than that which would be used if particles of the same composition as the nanoparticles but having diameters of about 5 μm to about 100 μm were used.

[0020] Embodiment 17 is the method of any one of embodiments 1 to 16, wherein the sintering temperature is 1000° C. or less.

[0021] Embodiment 18 is the method of any one of embodiments 1 to 17, wherein the substrate is a porous carbonized substrate.

[0022] In embodiment 19, a method for forming a ceramic-based material includes depositing a ceramic precursor composition, comprising ceramic nanoparticles having at least one dimension less than 100 nm and an aspect ratio greater than or equal to 1.5 and a carrier fluid, onto a surface of a substrate by layer-by-layer deposition to form an as-deposited layer of the ceramic precursor composition; and sintering the as-deposited multi-layer structure at a sintering temperature to form the ceramic-based material.

[0023] Embodiment 20 is the method of embodiment 19, further comprising depositing a composition comprising a non-ceramic material by layer-by-layer deposition to form a layer of the non-ceramic material in the as-deposited multilayer structure.

[0024] Other principal features and advantages of the present disclosure will become apparent to those skilled in the art upon review of the following drawings, detailed description, and appended claims.

[0025] Exemplary embodiments of the present disclosure will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic diagram illustrating the layer-by-layer deposition of ceramic precursor compositions 1 and 2, each comprising ceramic nanoplatelets dispersed in a carrier fluid, according to an exemplary embodiment of the present method. The resulting multilayer structure is also shown. [Figure 2] FIG. 1 is a schematic diagram illustrating the use of roll-to-roll coating as an additive technique to perform layer-by-layer deposition of cationic and anionic ceramic precursor compositions, according to one exemplary embodiment of the present disclosure. [Figure 3] 1 is a scanning electron microscope (SEM) image of an aramid nanofiber scaffold, which may be used as a porous substrate in embodiments of the present method. Such a porous substrate may be pyrolyzed to form an N-doped carbon foam prior to depositing the ceramic precursor composition. [Figure 4] FIG. 4 is a schematic diagram illustrating the conversion of an N-doped carbon foam, such as that formed from the aramid nanofiber scaffold of FIG. 3, into a ceramic-based material according to an exemplary embodiment of the present method. DETAILED DESCRIPTION OF THE INVENTION

[0027] Methods are provided for forming ceramic-based materials, including coatings and three-dimensional (3D) objects.

[0028] The method includes depositing a ceramic precursor composition including nanoparticles and a carrier fluid onto a surface of a substrate to form an as-deposited layer of the ceramic precursor composition on the surface. The deposition may be performed once to form a single layer, but is typically performed multiple times to form a multilayer structure. In some embodiments, each layer has an opposite charge to the previously deposited layer below (after rinsing any excess material that may remain from the previously deposited layer below). The layers are bonded by covalent and non-covalent forces. Prior to deposition of the first layer of ceramic precursor composition, the substrate may be prepared by treating the area of ​​the substrate to be coated so that it has an opposite charge to the first layer. If the same ceramic precursor composition is used during the multiple depositions, the chemical composition of the individual layers of the multilayer structure will be the same. If different ceramic precursor compositions with different chemical compositions are used, the chemical compositions of the individual layers will be different. Other types of compositions (e.g., those including other materials, including non-ceramic materials) may also be deposited to include other materials within the multilayer structure. This is useful for providing ceramic composites. As will be explained further below, various deposition techniques may be used, but the temperatures used during deposition are relatively low, e.g., room temperature. The as-deposited (multi-)layers are then sintered to form the ceramic-based material. As will be explained further below, the temperatures used during sintering are lower than temperatures typically used to sinter ceramics. This includes, for example, using sintering temperatures below 1000°C.

[0029] The nanoparticles used in the present methods may be characterized by their morphology and dimensions. However, nanoparticles are generally non-spherical, having an aspect ratio of 1.5 or greater. This includes aspect ratios of 1.7, 2, 5, 10, 50, 100, etc. At least one dimension of the nanoparticle is nanoscale, i.e., 100 nm or less. This includes nanoparticles in which one, two, or all three dimensions are nanoscale. The nanoscale dimension(s) may be 90 nm or less, 70 nm or less, 50 nm or less, or 25 nm or less. This includes embodiments in which the nanoscale dimension(s) is in the range of 1 nm to 20 nm, 1 nm to 15 nm, 1 nm to 10 nm, 1 nm to 5 nm, and 2 nm to 5 nm. Any non-nanoscale dimension (if any) is greater than 100 nm. Non-spherical nanoparticle shapes include, for example, nanorods, nanotubes, nanofibers, nanowhiskers, nanodisks, nanoplates, nanoplatelets, nanoflakes, and the like. FIG. 1 shows an exemplary nanoplatelet shape. However, nanoplatelets need not have perfectly circular cross-sections or be completely uniform as depicted in the schematic diagram. While each of the three dimensions of such nanoplatelets may be nanoscale, as noted above, the aspect ratio of nanoplatelets is greater than 1, 1, or 1.5 (in the x, y, and z directions, respectively), e.g., 1.5 or greater, resulting in a relatively large surface-to-volume ratio. In some embodiments, the nanoparticle is a nanoplatelet having at least one dimension (z-direction) in the range of 1 to 100 nm. This includes at least one dimension (z-direction) in the range of 1 to 50 nm, 1 to 25 nm, 1 to 5 nm, or 2 to 5 nm. In some embodiments, the nanoparticle is a nanoplatelet having at least two or all three dimensions within any of these ranges. The use of nanoparticles having nanoscale dimensions (one or more), such as nanoplatelets, contrasts with the typical size (e.g., 5 μm to 100 μm) of ceramic particles used to form high temperature ceramics using existing methods.The aspect ratios and dimensions of the nanoparticles may refer to average values, ie, values ​​averaged over a representative number of nanoparticles.

[0030] The composition of the nanoparticles is generally a ceramic compound. Ceramic compounds refer to inorganic (although elements in ceramic compounds can include carbon), non-metallic (although elements in ceramic compounds can include metals), and crystalline (i.e., not amorphous) solids. Exemplary ceramic compounds include oxides such as alumina, beryllia, ceria, zirconia, and hafnia. Ceramic compounds also include non-oxides such as borides, carbides, carbonates, nitrides, phosphates, silicides, and phosphates. Oxides and non-oxides include, but are not limited to, metals and semi-metals such as calcium, titanium, hafnium, and silicon. Specific exemplary ceramic compounds include boron oxide, boron nitride, silicon aluminum oxynitride, silicon carbide, silicon nitride, tantalum carbide, hafnium carbide, titanium carbide, tungsten oxide, and tungsten carbide. In embodiments, the nanoparticles are composed of WO, ceria, hafnia, or titania.

[0031] In some embodiments, instead of the nanoparticles being composed of a ceramic compound, the nanoparticles are composed of a material that can form a ceramic compound during a method step, such as sintering. This includes nanoparticles that form a ceramic compound with the substrate during the method steps. Ceramic compounds that may be formed include any of those described above.

[0032] A single type of nanoparticle (e.g., having a single type of chemical composition) may be used, or a combination of different types (e.g., having multiple types of chemical compositions) may be used. In some embodiments, a single type of nanoparticle is used.

[0033] Nanoparticles may also be characterized by their crystallinity. In embodiments, the nanoparticles are monocrystalline, meaning that they are composed of a single crystalline phase (i.e., not polycrystalline).

[0034] The nanoparticles can be unfunctionalized, functionalized (e.g., to facilitate their dispersion in a carrier fluid), or carry spontaneously formed (i.e., self-assembled onto a substrate via surface adsorption) layers, or both, to provide desired components for the ceramic composite formed using the present methods. For example, during sintering, the organic ligands of organically functionalized nanoparticles can be carbonized, thereby providing carbon as a component of the ceramic composite. Functionalization can also be used to achieve nanoparticles with a desired overall charge, which is useful for layer-by-layer deposition as described below.

[0035] The carrier fluid provides a medium for dispersing and transporting the nanoparticles. The carrier fluid desirably enables the formation of a stable dispersion of nanoparticles, i.e., a colloid. The carrier fluid may also be used to impart a desired overall charge to the as-deposited layer to facilitate layer-by-layer deposition, as described below. Thus, the selection of an appropriate carrier fluid may depend on the desired nanoparticles and the deposition technique used. A single type of carrier fluid (e.g., a single chemical composition) or a combination of different types (e.g., different chemical compositions) may be used.

[0036] Exemplary carrier fluids include water, organic solvents, ionic liquids, and polymers or their precursors. Short-chain alcohols such as ethanol, methanol, and isopropyl alcohol may be used. Ionic liquids include materials containing one or more cations and one or more anions and having a melting point below room temperature. Exemplary anions for ionic liquids include trifluoromethylsulfonate ("triflate," CF3SO3-), bis(trifluoromethylsulfonyl)imide (N(CF3SO2)2-), bis(perfluoroethylsulfonyl)imide (((CF5SO2)2N-)), tris(trifluoromethylsulfonyl)methide ((((CF3SO2)3C-)), tetrafluoroborate (BF4-), hexafluorophosphate (PF6-), hexafluoroantimonate (SbF6-), and hexafluoroarsenate (AsF6-). Mixtures or combinations of different anions may also be used.

[0037] Other suitable commercially available ionic liquids include the Basionic® ionic liquid products available from BASF (Florham Park, New Jersey, USA), including 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium methanesulfonate, methyl-tri-n-butylammonium methyl sulfate, 1,2,4-trimethylpyrazolium methyl sulfate, 1-ethyl-2,3-di-methylimidazolium ethyl sulfate, 1,2,3-trimethylimidazolium methyl sulfate, methylimidazolium chloride, methylimidazolium hydrogen sulfate, 1-ethyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-methyl Examples of suitable ionic liquids include imidazolium tetrachloroaluminate, 1-butyl-3-methylimidazolium hydrogen sulfate, 1-butyl-3-methylimidazolium tetrachloroaluminate, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-butyl-3-methylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-butyl-3-methylimidazolium thiocyanate, choline acetate, choline salicylate, and tris-(2-hydroxyethyl)-methylammonium methyl sulfate. Mixtures or combinations of different ionic liquids may also be used.

[0038] Exemplary cations for ionic liquids include tetraalkylammonium cations. Quaternary ammonium cations may be substituted with H, F, phenyl, alkyl groups having 1 to 15 carbon atoms, and other chemical substituents. The cations may also have bridged cyclic structures. Mixtures or combinations of different cations may also be used.

[0039] Other exemplary cations for ionic liquids include imidazolium, pyridinium, pyridinium, pyrazinium, pyrazolium, oxazolium, 1,2,3-triazolium, 1,2,4-triazolium, thiazolium, piperidinium, pyrrolidinium, quinolinium, and isoquinolinium.

[0040] While organic cations / anions may be used, in embodiments, the ionic liquid contains only inorganic ions to provide inorganic ionic liquids, including those composed of metal halides, such as mixed metal halides, and thiocyanates. Inorganic ionic liquids are useful for enhancing the heat and oxidation resistance of ceramic-based materials formed using the present methods.

[0041] In embodiments, a polymer or a precursor thereof is used as the carrier fluid. By "precursor" is meant a compound capable of forming a polymer during a method step, e.g., sintering. While organic polymers / precursors may be used, in embodiments, the polymer / precursor is an inorganic polymer (i.e., does not contain carbon atoms in its polymer backbone). Again, inorganic polymers are useful for enhancing heat and oxidation resistance. Polysiloxane, polysilazanes, polyphosphazenes, polyborazylenes, and polyaminoboranes are exemplary inorganic polymers. For purposes of this disclosure, inorganic polymers such as those described above but which also contain organic substituents may be used and may be referred to as inorganic polymers.

[0042] Additives may be included in the ceramic precursor composition as needed to adjust its properties and those of the desired ceramic material. Additives that stabilize the dispersion of nanoparticles in the ceramic precursor composition may be used. Additives (described below) that promote chemical transformations during sintering may also be included. Exemplary additives include, for example, organic substances, metal salts, boric acid, and ammonium salts.

[0043] Various loadings of nanoparticles and, if present, additives may be included in the carrier fluid to form the ceramic precursor composition, and the loading amount may be readily determined based on the type of nanoparticles and carrier fluid used.

[0044] Various thin film deposition techniques can be used to form the as-deposited (multi-)layers. However, deposition techniques can be performed using relatively low temperatures, including room temperature (20°C to 25°C). Furthermore, a range of deposition temperatures, e.g., 10°C to 100°C, can be used depending on the thermal properties of the carrier fluid. Thus, deposition temperatures can be below 100°C. One example is layer-by-layer deposition. Layer-by-layer deposition generally involves sequentially applying compositions to the surface of a substrate to build a multilayer structure. Application methods include spraying (see FIG. 1), dip coating, spin coating, roll-to-roll coating (see FIG. 2), immersion, and the like. As shown in FIG. 1, application results in the self-assembly of nanoparticles into a relatively densely packed monolayer, facilitated by their relatively high aspect ratio. Individual layers can be adhered together within the multilayer structure via electrostatic interactions (e.g., two ceramic precursor compositions with opposite charges via charged nanoparticles, a charged carrier fluid, or a combination thereof). However, other non-covalent or covalent interactions may be used to bond adjacent layers. Rinsing may be used between the addition of individual layers. Drying / heating may be used between the addition of individual layers as needed. Prior to the deposition of the first layer, the substrate surface may be chemically and / or mechanically treated to create a charged surface. After the deposition of each individual layer and before the deposition of additional layers, excess carrier fluid may be removed and recycled via heating or other means prior to the deposition of the subsequent layer. Any desired number and sequence of additions may be used to achieve a variety of multilayer structures with varying compositions, properties, and overall thicknesses (e.g., nanometers to microns, microns to millimeters). Layer-by-layer deposition is often used with at least two compositions having different chemical compositions, but this is not required. For example, two ceramic precursor compositions having the same type of nanoparticles (e.g., the same chemical composition) but different charges may be used. As noted above, other types of compositions (e.g., those containing other materials, including non-ceramic materials) may be deposited using layer-by-layer deposition, including the inclusion of other materials within the multilayer structure.This is useful for providing ceramic composites.

[0045] It should be noted that layer-by-layer deposition allows for very high loadings of nanoparticles, much higher than is possible with existing technologies. Additionally, such loadings can be tailored for each individual layer, so that each layer may have the same or different loadings of nanoparticles. Additionally, each layer or combination of layers may include loadings tailored to desired performance levels for any of the properties described herein.

[0046] Another low-temperature deposition technique that may be used is freeze casting. In this embodiment, after application of a ceramic precursor composition to the surface of a substrate (such application may be performed using layer-by-layer deposition as described above), a directional temperature gradient is applied to induce freezing of a carrier fluid (e.g., water) and alignment of the nanoparticles. The frozen carrier fluid may be removed (e.g., by sublimation) to form a porous (multi-)layer of aligned nanoparticles.

[0047] The ceramic precursor composition may be deposited on a variety of substrates as desired. Substrates with planar (i.e., flat) and non-planar (e.g., curved, 3D) surfaces may be used. Porous substrates, such as those formed from filamentary or woven / non-woven carbon or ceramic fibers (e.g., aramid nanofibers), may be used. Such porous substrates may be pyrolyzed to form undoped or doped carbon foams prior to deposition of the ceramic precursor composition. The selection of substrate material may be guided by the requirements for the substrate to form ceramic compounds with nanoparticles, provide components (e.g., carbon) for ceramic composites, and / or achieve desired chemical and / or physical transformations during sintering (described further below). Other exemplary substrate materials include silica, carbon, metals, and ceramics (e.g., silicon carbide).

[0048] As described above, the present method further includes sintering the as-deposited (multi)layer to provide a ceramic-based material. Sintering involves heating the as-deposited (multi)layer to a sintering temperature for a period of time. The sintering temperature is high enough to achieve densification and / or fusion of the individual nanoparticles to form a solid matrix. This may include coalescence of the crystal lattices of the individual nanoparticles. However, with the use of the present nanoparticles, the temperature at which sintering occurs is lower than existing methods of forming ceramics. The specific sintering temperature depends, at least in part, on the composition of the nanoparticles. However, as a sole example, the sintering temperature for an as-deposited layer of a ceramic precursor composition including ceramic nanoparticles having one or more dimensions between 2 and 5 nm may be at least 300°C lower than the sintering temperature required when larger ceramic particles are used (e.g., when using particulates having a diameter of 5 to 100 μm) (sintered under otherwise the same conditions, e.g., sintering time). This includes at least 400°C lower, at least 500°C lower, at least 600°C lower, or at least 700°C lower. In some embodiments, the sintering temperature is 1000°C or less. This includes 950°C or less, 900°C or less, 850°C or less, 800°C or less, or in the range of 100°C to 1000°C. These temperatures may refer to sintering in the absence of additional external forces, such as pressure. This does not exclude the application of pressure during sintering, in which case the sintering temperature may be further reduced. Sintering may be induced by light, such as light-induced sintering with a laser or other focused light source, in which case the sintering temperature refers to light-induced heating. The above temperatures may refer to sintering for a specific time range, for example, from a few seconds to a few hours. Sintering may be performed in situ after deposition.

[0049] Figure 3 is an SEM image of an aramid nanofiber scaffold that may be used as an exemplary porous substrate. As described above, such a porous substrate can be pyrolyzed to form an N-doped carbon foam. Figure 4 is a schematic diagram illustrating the conversion of such an N-doped carbon foam 400 into a ceramic-based material 408 according to an exemplary embodiment of the present method. As shown in step 402, any of the ceramic precursor compositions of the present disclosure, including, for example, nanoplatelets 404, may be deposited onto the surface of the N-doped carbon foam 400, followed by in-situ sintering via step 406 to form the ceramic-based material 408. Densification, for example, via hot pressing, may also be used, as shown in step 410.

[0050] Other chemical and physical transformations (apart from densification and / or fusion of nanoparticles) may occur during sintering. Transformations involving individual nanoparticles and / or the substrate, and / or transformations between nanoparticles and the substrate, include decomposition and / or carbonization of ligands on functionalized nanoparticles, hydrogen bonding, non-classical crystallization, mesophase seeded growth, substrate seeded crystallization, ion exchange, recrystallization of nanoparticles, self-assembly of nanoparticles into other morphologies such as chains / sheets / capsules, ionic, covalent, or coordinate bonding with the substrate, and densification of the substrate and nanoparticles. Chemical and physical transformations that may occur involving the carrier fluid include evaporation, polymerization, decomposition / carbonization, covalent bonding to nanoparticles, and crystallization of ceramic phases therefrom.

[0051] The composition, morphology, and dimensions of the ceramic-based material formed using the present method depend on the details discussed above. However, generally, the ceramic-based material is either in the form of a coating attached to a substrate or a 3D object. If the coating or 3D object is composed exclusively or primarily of a ceramic compound, it may be referred to as a ceramic coating / 3D object. If the coating or 3D object includes a non-ceramic material (e.g., non-carbide carbon), it may be referred to as a ceramic composite coating / 3D object. The distinction between a coating and a 3D object is not intended to be particularly limiting. However, generally, a coating may be thick (e.g., mm), but the other two dimensions are significantly larger than its thickness. In contrast, a 3D object may be small, but is generally at the microscale or larger, with three dimensions that are more similar in size to one another.

[0052] Ceramic-based materials formed using this method may be characterized by various properties. These include tensile strength (σ). Tensile testing of coatings may be performed by indentation testing using a standard Hysitron nanoindenter. Load-deformation curves can be obtained using a Berkovich tip. Stress-strain curves of ceramic composites may be performed on rectangular strips ~1 mm wide and 4-6 mm long. Properties also include Young's modulus (E), which may be quantified using compression testing and evaluation of E in the deformation plateau region. Other properties include electrical conductivity, adhesion, and density, which may be measured according to ASTM (American Society for Testing and Materials) standards used in the aeronautical industry. The specific values ​​of each of these properties depend on the type of ceramic-based material used. Advantageously, these values ​​may be tailored to the selected substrate to facilitate adhesion over a wide temperature range and meet the requirements of the intended use.

[0053] The method may be used to provide ceramic-based materials for use in a variety of environments, such as aerospace, automotive, marine, electronics, construction, etc. Thus, the terms "aerospace," "automotive," and "marine" may refer to any equipment, craft, machine, or component thereof used in the industries, such as aircraft, planes, rotorcraft, boats, submarines, spacecraft, orbital vehicles, drones, satellites, automobiles, buses, railways, trains, etc.

[0054] Furthermore, the present disclosure includes embodiments according to the following clauses.

[0055] 1. 1. A method for forming a ceramic-based material, comprising: depositing (402) a ceramic precursor composition comprising nanoparticles having at least one dimension less than 100 nm and an aspect ratio of 1.5 or greater and a carrier fluid onto a surface of a substrate 400 to form an as-deposited layer of the ceramic precursor composition; and sintering (406) the as-deposited layer of the ceramic precursor composition at a sintering temperature to form a ceramic-based material (408).

[0056] 2. 10. The method of claim 1, wherein the nanoparticles have at least one dimension in the range of 1 nm to 100 nm, and preferably the nanoparticles are nanoplatelets 404.

[0057] 3. 3. The method of claim 1 or 2, wherein the nanoparticles comprise a ceramic compound, preferably the nanoparticles comprise WO3, ceria, hafnia, titania, or a combination thereof.

[0058] 4. 4. The method of any one of clauses 1 to 3, wherein the nanoparticles comprise a compound that forms a ceramic compound during sintering (406).

[0059] 5. 5. The method of any one of clauses 1 to 4, wherein the nanoparticles are single crystalline.

[0060] 6. 6. The method of any one of clauses 1 to 5, wherein the carrier fluid is water, an organic solvent, or an ionic liquid.

[0061] 7. 7. The method of any one of clauses 1 to 6, wherein the carrier fluid is an inorganic ionic liquid.

[0062] 8. 8. The method of any one of clauses 1 to 7, wherein the carrier fluid is a polymer or a precursor thereof, preferably the polymer is an inorganic polymer or a precursor thereof.

[0063] 9. 9. The method of any one of clauses 1 to 8, wherein the depositing (402) is carried out at a temperature of less than 100° C., preferably the depositing (402) is carried out at room temperature or below.

[0064] 10. 10. The method of any one of clauses 1 to 9, wherein the depositing (402) is performed using layer-by-layer deposition to provide an as-deposited multilayer structure comprising the as-deposited layers of the ceramic precursor composition.

[0065] 11. 11. The method of any one of clauses 1 to 10, wherein the sintering temperature is less than the sintering temperature that would be used if particles of the same composition as the nanoparticles but having a diameter of about 5 μm to about 100 μm were used.

[0066] 12. 12. The method of any one of clauses 1 to 11, wherein the sintering temperature is 1000°C or less.

[0067] 13. 13. The method of any one of clauses 1 to 12, wherein the substrate 400 is a porous carbonized substrate.

[0068] 14. 14. The method of any one of clauses 1 to 13, wherein the nanoparticles comprise a ceramic compound, and wherein the depositing (402) is performed using layer-by-layer deposition to provide an as-deposited multilayer structure comprising the as-deposited layer of the ceramic precursor composition.

[0069] 15. 15. The method of claim 14, further comprising depositing a composition comprising the non-ceramic material by layer-by-layer deposition to form a layer of the non-ceramic material in the as-deposited multi-layer structure.

[0070] The word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Further, for the purposes of this disclosure, unless expressly stated otherwise, "a" or "an" means "one or more."

[0071] Unless already included, all numerical values ​​of parameters in this disclosure are intended to be preceded by the term "about," which means approximately. This encompasses the inherent variation in measurement of the relevant parameter as understood by one of ordinary skill in the art. This also encompasses the exact value of the disclosed numerical value and values ​​that are rounded to the disclosed numerical value.

[0072] The foregoing description of exemplary embodiments of the present disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, as modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosure. The embodiments were chosen and described to explain the principles of the present disclosure, with various modifications suited to the particular uses intended, as practical applications to enable those skilled in the art to utilize the present disclosure in various embodiments. It is intended that the scope of the present disclosure be defined by the claims appended hereto and their equivalents.

Claims

1. 1. A method for forming a ceramic-based material, comprising: a. depositing 402 a ceramic precursor composition comprising nanoparticles having at least one dimension less than 100 nm and an aspect ratio of 1.5 or greater and a carrier fluid onto a surface of a substrate 400 to form an as-deposited layer of the ceramic precursor composition; b. sintering 406 the as-deposited layer of the ceramic precursor composition at a sintering temperature to form a ceramic-based material 408.

2. The method of claim 1 , wherein the nanoparticles have at least one dimension in the range of 1 nm to 100 nm.

3. The method of claim 1 or 2, wherein the nanoparticles comprise a ceramic compound.

4. The method of claim 1 , wherein the nanoparticles comprise a compound that forms a ceramic compound during sintering (406).

5. The method of claim 1 , wherein the nanoparticles are single crystalline.

6. The method of claim 1 , wherein the carrier fluid is water, an organic solvent, or an ionic liquid.

7. The method of claim 1 , wherein the carrier fluid is an inorganic ionic liquid.

8. The method of claim 1 , wherein the carrier fluid is a polymer or a precursor thereof.

9. The method of claim 1 , wherein the depositing (402) is performed at a temperature less than 100° C.

10. 10. The method of claim 1, wherein the depositing (402) is performed using layer-by-layer deposition to provide an as-deposited multi-layer structure including the as-deposited layer of the ceramic precursor composition.

11. 10. The method of claim 1, wherein the sintering temperature is less than the sintering temperature that would be used if particles of the same composition as the nanoparticles but having a diameter of about 5 μm to about 100 μm were used.

12. The method of claim 1 , wherein the sintering temperature is 1000° C. or less.

13. The method of claim 1 , wherein the substrate 400 is a porous carbonized substrate.

14. 10. The method of claim 1, wherein the nanoparticles comprise a ceramic compound, and the depositing (402) is carried out using layer-by-layer deposition to provide an as-deposited multilayer structure including the as-deposited layer of the ceramic precursor composition.

15. 15. The method of claim 14, further comprising depositing a composition comprising the non-ceramic material by layer-by-layer deposition to form a layer of the non-ceramic material in the as-deposited multi-layer structure.

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