High-performance hafnium-based ultrahigh-temperature ceramic-based composite material and preparation method thereof

Abstract

The invention relates to a high-performance hafnium-based ultrahigh-temperature ceramic-based composite material and a preparation method thereof. The method comprises the following steps: depositing pyrolytic carbon on the carbon fiber surface of a carbon fiber preform through a CVD (Chemical Vapor Deposition) method; preparing a hafnium oxide interface layer on the surface of the pyrolytic carbon through an atomic layer deposition method, and performing ultra-fast annealing treatment to form a pyrolytic carbon-hafnium oxide composite interface layer; carrying out a reaction with a matrix containing a pyrolytic carbon-hafnium oxide composite interface layer through an impregnation pyrolysis method; a hafnium carbide coating is prepared on the surface of the composite material matrix through a CVD method; and preparing a hafnium oxide coating on the surface of the hafnium carbide coating through an atomic layer deposition method, and carrying out ultra-fast annealing treatment to prepare the high-performance hafnium-based ultra-high-temperature ceramic-based composite material. According to the preparation method, the pyrolytic carbon-hafnium oxide composite interface layer is prepared by adopting an atomic layer deposition process and depending on ultra-fast annealing treatment, and meanwhile, the hafnium carbide-hafnium oxide composite coating is prepared, so that the mechanical property of the composite material in a high-temperature aerobic environment is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic matrix composite material preparation technology, and particularly relates to a high-performance hafnium-based ultra-high temperature ceramic matrix composite material and its preparation method. Background Technology

[0002] Ceramic matrix composites, as a novel type of composite material, have attracted widespread attention in high-precision fields. Through techniques such as chemical vapor deposition, precursor impregnation pyrolysis, and reactive infiltration, ceramic matrix composites can effectively achieve the uniform composite of continuous carbon fibers and high-performance ceramics. Due to the high melting point and high strength of the high-performance ceramics, ceramic matrix composites also possess characteristics such as high temperature resistance, ablation resistance, and toughening, making them suitable for use in thermal structural components. However, both carbon fibers and high-performance ceramics, represented by hafnium carbide, suffer from weak oxidation resistance: the former's performance deteriorates due to oxidation at only 400℃ in air, while the latter's initial oxidation temperature is mostly below 1000℃. This characteristic significantly restricts the operating environment of thermal structural components: when these components re-enter the atmosphere, the surface temperature of the materials often reaches above 1500℃, and they need to be exposed to the air for extended periods. Rapid oxidation of both carbon fibers and ceramics leads to a decline in mechanical properties, resulting in a loss of structural support capacity and ultimately, rapid failure of the overall material performance.

[0003] To address the aforementioned issues and improve the long-term performance of ceramic matrix composites in air environments, researchers have designed ceramic coatings as thermally protective phases for the matrix, preventing contact between the matrix components and oxygen, achieving some improvement. However, limitations in technologies such as chemical vapor deposition and plasma spraying prevent the effective fabrication of highly dense and uniform ceramic coatings, leaving the materials still vulnerable to oxygen penetration and reaction under prolonged air exposure. Therefore, to promote the application of ceramic matrix composites, strengthening the oxidation resistance of the internal carbon fibers and matrix while ensuring reliable mechanical properties in extreme aerobic environments has become a key research direction in this field.

[0004] In summary, it is essential to provide a high-performance hafnium-based ultra-high temperature ceramic matrix composite material and its preparation method. Summary of the Invention

[0005] To address one or more technical problems existing in the prior art, this invention provides a high-performance hafnium-based ultra-high temperature ceramic matrix composite material and its preparation method. This invention employs atomic layer deposition (ALD) and ultra-fast annealing to prepare a pyrolytic carbon-hafnium oxide composite interface layer, achieving effective protection of the carbon fibers. Simultaneously, a hafnium carbide-hafnium oxide composite coating is prepared, significantly improving the mechanical properties of the composite material in high-temperature aerobic environments. This solves the problem of generally poor high-temperature aerobic mechanical properties in ceramic matrix composites prepared by traditional techniques, and enhances the reliability of the mechanical properties of ceramic matrix composites in extreme aerobic environments.

[0006] The present invention provides a method for preparing a high-performance hafnium-based ultra-high temperature ceramic matrix composite material in a first aspect, the method comprising the following steps: (1) A porous carbon / carbon composite matrix is ​​obtained by depositing a pyrolytic carbon interface layer on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition. (2) Using tetramethylethylamine hafnium and water as reactants, a hafnium oxide interface layer was prepared on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix by atomic layer deposition and subjected to ultra-fast annealing treatment to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer. (3) Using hafnium carbide ceramic precursor as reactant, react with the composite matrix containing the pyrolytic carbon-hafnium oxide composite interface layer by impregnation pyrolysis method to obtain hafnium-based ultra-high temperature ceramic matrix composite matrix; (4) A hafnium carbide coating was prepared on the surface of the hafnium-based ultra-high temperature ceramic matrix composite material matrix by chemical vapor deposition; (5) Using tetramethylethylamine hafnium and water as reactants, a hafnium oxide coating is prepared on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite matrix by atomic layer deposition and ultra-fast annealing treatment is performed to obtain a high-performance hafnium-based ultra-high temperature ceramic matrix composite.

[0007] Preferably, the density of the carbon fiber preform is 0.15~0.2 g / cm³. 3 The thickness is 1~4mm; and / or the density of the porous carbon / carbon composite matrix is ​​0.2~0.25g / cm³. 3 .

[0008] Preferably, the thickness of the hafnium oxide interface layer is 25~100nm, more preferably 50~100nm; and / or the thickness of the pyrolytic carbon-hafnium oxide composite interface layer is 0.2~1μm.

[0009] Preferably, the thickness of the hafnium carbide coating is 0.5~5μm; and / or the thickness of the hafnium oxide coating is 50~200nm, preferably 150~200nm.

[0010] Preferably, in step (2) and / or step (5): the precursor used in the atomic layer deposition process is tetramethylethylaminohafnium and ultrapure water, and the temperature of the atomic layer deposition reaction is 220~300℃; in step (2), the number of deposition cycles is 100~2000 times; in step (5), the number of deposition cycles is 200~4000 times; a single deposition cycle is as follows: the pulse time of the tetramethylethylaminohafnium is 0.3~0.6s, and the argon purging time is 1~3s; the pulse time of the ultrapure water is 0.1~0.3s, and the argon purging time is 1~3s.

[0011] Preferably, in step (2) and / or step (5): the ultra-fast annealing process is to heat to 650-850℃ at a heating rate of 25-50℃ / s and hold for 40-100s.

[0012] Preferably, in step (3), the pyrolysis temperature is 1200~1450℃.

[0013] Preferably, in step (4): when preparing the hafnium carbide coating, the temperature of chemical vapor deposition is 1100~1400℃, the pressure is 0.1~50Pa, and / or the time is 1~2h.

[0014] Preferably, the high-performance hafnium-based ultra-high temperature ceramic matrix composite material contains a hafnium carbide-hafnium oxide composite coating; and / or the high-performance hafnium-based ultra-high temperature ceramic matrix composite material has a tensile strength greater than 170 MPa at 2000°C in air atmosphere.

[0015] The present invention provides, in a second aspect, a high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared by the preparation method described in the first aspect of the present invention.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Hafnium carbide interface layers can be prepared on the surface of carbon fibers using conventional chemical vapor deposition techniques, but due to uneven deposition, it is difficult to achieve excellent protective effects. Unlike the existing techniques that usually form a pyrolytic carbon-hafnium carbide interface layer, this invention uses tetramethylethylamine hafnium as raw material and introduces a hafnium oxide ceramic interface layer on the surface of pyrolytic carbon for the first time through atomic layer deposition (ALD). The slow ALD deposition rate allows for precise control of extremely high flatness and thickness. At the same time, the ultra-fast annealing process further enhances the bonding force between the pyrolytic carbon and the hafnium oxide interface layer, resulting in better antioxidant protection.

[0017] (2) In the prior art, although there are reports of forming a pyrolytic carbon interface layer and a hafnium oxide layer on the surface of carbon fibers through a metal salt impregnation-sintering process, this process is limited by the diffusion behavior, wettability, and sintering conversion characteristics of metal salts in porous matrices. The resulting hafnium oxide interface layer often exhibits uneven thickness, high porosity, and insufficient structural bonding, making it difficult to form a stable and continuous interface structure. To improve the stability of the interface layer, the prior art usually performs carbothermal reduction after sintering to convert hafnium oxide into hafnium carbide, thereby obtaining a hafnium carbide interface layer. However, the existing process route is difficult to obtain a uniform and controllable hafnium oxide interface layer. Compared with the prior art, the present invention uses an atomic layer deposition process to deposit hafnium oxide on the surface of a pyrolytic carbon interface layer in a porous carbon / carbon matrix. This process has self-limiting growth characteristics and can achieve uniform coverage inside complex pore structures, obtaining a controllable thickness, continuous and dense hafnium oxide interface layer. Subsequent ultra-fast annealing of the interface layer further enhances its density and structural stability, improving the bonding strength and chemical stability of the interface. The resulting pyrolytic carbon-hafnium oxide composite interface structure exhibits excellent oxidation resistance, thermal stability, and stress relief characteristics, which helps maintain the toughening effect of carbon fibers and improve the service performance of the composite material under ultra-high temperature conditions. The process route of this invention can construct a stable hafnium oxide interface layer that is difficult to obtain in existing conventional impregnation-sintering systems, thereby significantly improving the interface structure and overall properties of the material.

[0018] (3) This invention uses a combination of chemical vapor deposition and atomic layer deposition to prepare a hafnium carbide coating on the surface of the material matrix, and then prepares a thin and flat hafnium oxide coating to form a hafnium carbide-hafnium oxide composite coating. At the same time, ultra-fast annealing is introduced to enhance the bonding force between the hafnium carbide coating and the hafnium oxide coating, improve the overall oxidation resistance of the material, and significantly improve the mechanical properties of hafnium-based ultra-high temperature ceramic matrix composites in high temperature and oxygen environment. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] The present invention provides a method for preparing a high-performance hafnium-based ultra-high temperature ceramic matrix composite material in a first aspect, the method comprising the following steps: (1) A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite matrix (also referred to as a porous carbon / carbon matrix); those skilled in the art can prepare the porous carbon / carbon composite matrix by conventional chemical vapor deposition; the carbon fiber preform can adopt any structure such as needle punching, puncture or stitching; (2) Using tetramethylethylamine hafnium and water as reactants, a hafnium oxide interface layer is prepared on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix by atomic layer deposition and then subjected to ultra-fast annealing treatment to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer; In this invention, a dense hafnium oxide interface layer can be prepared on the surface of pyrolytic carbon by atomic layer deposition and ultra-fast annealing treatment is used to promote hafnium oxide crystallization and improve the bonding force between the hafnium oxide interface layer and the pyrolytic carbon interface layer; (3) Using hafnium carbide ceramic precursor as reactant, react with the composite matrix containing the pyrolytic carbon-hafnium oxide composite interface layer by impregnation pyrolysis method to obtain hafnium-based ultra-high temperature ceramic matrix composite matrix; this step (3) is a well-known technology in the field, and those skilled in the art can prepare hafnium-based ultra-high temperature ceramic matrix composite matrix by using precursor impregnation pyrolysis technology, using carbide ceramic precursor as reactant, and performing multiple impregnation, curing and pyrolysis treatments; in this invention, the hafnium carbide ceramic precursor The body adopts the oxygen-free hafnium carbide ceramic precursor in the prior art; the present invention does not specify the parameters of impregnation, curing and pyrolysis, and those skilled in the art can conventionally select them. The hafnium carbide ceramic precursor is filled into the pores of the composite material matrix containing the pyrolytic carbon-hafnium oxide composite interface layer by vacuum and / or pressure impregnation, and the hafnium-based ultra-high temperature ceramic matrix matrix is ​​formed by curing and pyrolysis process; in step (3) of the present invention, the pyrolysis temperature is 1200~1450℃; (4) A hafnium carbide coating is prepared on the surface of the hafnium-based ultra-high temperature ceramic matrix composite material matrix by chemical vapor deposition. In this invention, step (4) is a well-known technology in the field. Those skilled in the art can use chemical vapor deposition technology to first draw a vacuum, heat hafnium tetrachloride, use hafnium tetrachloride, propane and hydrogen as reaction sources, use argon as carrier gas, and at the same time, make conventional adjustments to parameters such as temperature, holding time, hafnium tetrachloride, propane and hydrogen flow rate in the deposition chamber to prepare a hafnium carbide coating on the surface of the hafnium-based ultra-high temperature ceramic matrix composite material matrix. (5) Using tetramethylethylamine hafnium and water as reactants, a hafnium oxide coating is prepared on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite matrix by atomic layer deposition and then subjected to ultra-fast annealing to obtain a high-performance hafnium-based ultra-high temperature ceramic matrix composite. In this invention, an atomic layer deposition process is used to prepare a dense hafnium oxide coating on the surface of the hafnium carbide coating, and ultra-fast annealing is performed to promote hafnium oxide crystallization and improve the bonding force between the hafnium oxide coating and the zirconium oxide coating, forming a hafnium carbide-hafnium oxide composite interface layer. In this invention, the ultra-fast annealing is performed under an inert atmosphere or in a vacuum environment.

[0021] While conventional chemical vapor deposition (CVD) techniques can prepare hafnium carbide (HCC) interface layers on carbon fiber surfaces, the uneven deposition makes it difficult to achieve excellent protective effects. Unlike existing techniques that typically form a pyrolytic carbon-hafnium carbide interface layer, this invention uses tetramethylethylamine hafnium as a raw material and employs atomic layer deposition (ALD) to introduce a hafnium oxide ceramic interface layer onto the pyrolytic carbon surface for the first time. The slow ALD rate allows for precise control of extremely high flatness and thickness. Simultaneously, ultra-fast annealing further enhances the bonding between the pyrolytic carbon and the hafnium oxide interface layer, resulting in better antioxidant protection. While existing techniques have reported forming pyrolytic carbon and hafnium oxide interface layers on carbon fiber surfaces through metal salt impregnation-sintering, this process is limited by the diffusion behavior, wettability, and sintering transformation characteristics of metal salts in porous matrices. The resulting hafnium oxide interface layers often exhibit uneven thickness, high porosity, and insufficient structural bonding, making it difficult to form a stable and continuous interface structure. To improve the stability of the interface layer, existing technologies typically involve carbothermic reduction after sintering to convert hafnium oxide into hafnium carbide, thereby obtaining a hafnium carbide interface layer. However, existing processes struggle to achieve a uniform and controllable hafnium oxide interface layer. In contrast, this invention employs atomic layer deposition (ALD) to deposit hafnium oxide on the surface of a pyrolytic carbon interface layer within a porous carbon / carbon matrix. This process features self-limiting growth, enabling uniform coverage within complex pore structures and yielding a controllable, continuous, and dense hafnium oxide interface layer. Subsequent ultra-rapid annealing further enhances the interface layer's density and structural stability, improving the bonding strength and chemical stability. The resulting pyrolytic carbon-hafnium oxide composite interface structure exhibits excellent oxidation resistance, thermal stability, and stress relief characteristics, which helps maintain the toughening effect of carbon fibers and improves the composite material's performance under ultra-high temperature conditions. This invention's process path can construct a stable hafnium oxide interface layer that is difficult to obtain using conventional impregnation-sintering systems, thus significantly improving the material's interface structure and overall properties.

[0022] This invention utilizes a combination of chemical vapor deposition (CVD) and atomic layer deposition (ALD) techniques to prepare a hafnium carbide (HfC) coating on the surface of a material substrate, followed by a thin and smooth hafnium oxide (HCO) coating, forming a hafnium carbide-hafnium oxide (HCO) composite coating. Simultaneously, an ultra-fast annealing process is introduced to enhance the adhesion between the HfC and HCO coatings, improving the overall oxidation resistance of the material and significantly enhancing the mechanical properties of hafnium-based ultra-high temperature ceramic matrix composites in high-temperature aerobic environments. In existing technologies, surface protection of hafnium-based ceramic matrix composites often employs CVD to prepare a hafnium carbide (HfC) coating to improve its oxidation and ablation resistance. However, a single-layer hafnium carbide coating oxidizes in ultra-high temperature aerobic environments, accompanied by volume expansion and phase structure changes. This easily leads to stress concentration within the coating, resulting in microcracks, pore expansion, and coating peeling, making it difficult to maintain structural integrity and high mechanical properties under extreme service conditions. Although hafnium oxide theoretically possesses high thermal stability and chemical inertness, its coefficient of linear expansion differs significantly from that of the hafnium carbide matrix. Under high-temperature conditions, thermal stress tends to concentrate at the interface, and uniformity and density are difficult to guarantee, making it challenging to form a reliable and stable protective layer. Therefore, there are no reports in the existing technology regarding the direct preparation of a single-layer hafnium oxide coating or the construction of a hafnium carbide-hafnium oxide composite coating. This invention utilizes atomic layer deposition combined with ultrafast annealing technology to construct a uniform and dense hafnium oxide coating layer on the surface of a hafnium carbide coating, which is highly matched with the underlying hafnium carbide layer, forming a hafnium carbide-hafnium oxide composite coating structure. In this structure, the outer hafnium oxide layer provides oxidation resistance and stability under extreme high-temperature conditions, while the inner hafnium carbide layer provides a high melting point, high thermal conductivity, and good thermal stress buffering capacity. The two form a gradient thermally stable transition structure, enabling the coating to maintain superior oxidation resistance, ablation resistance, and high-temperature mechanical properties. Meanwhile, the hafnium carbide-hafnium oxide composite coating and the internal pyrolytic carbon-hafnium oxide composite interface layer are matched in terms of thermal expansion coefficient and structure, forming an overall protection system of "internal interface stability - external layer anti-oxidation" from the interface to the surface, which significantly improves the high-temperature service performance and structural reliability of the material.

[0023] According to some preferred embodiments, the density of the carbon fiber preform is 0.15~0.2 g / cm³. 3The thickness is 1~4mm (e.g., 1, 1.5, 2, 2.5, 3, 3.5 or 4mm), preferably 2~4mm; the key point of step (1) of the present invention is that the thickness of the carbon fiber preform is preferably 1~4mm. The present invention found that if the thickness is greater than 4mm, the diffusion distance will be longer, so that the tetramethyl ethylamine hafnium in the subsequent step (2) cannot effectively diffuse into the pores of the central region of the carbon fiber preform. The hafnium oxide deposition on the pyrolytic carbon surface in this region is uneven, and the carbon fiber cannot be effectively protected; if the thickness is less than 1mm, the carbon fiber preform will not be able to achieve self-support, which may lead to deformation of the composite material structure in the subsequent composite process; and / or the density of the porous carbon / carbon composite matrix is ​​0.2~0.25g / cm³. 3 .

[0024] According to some preferred embodiments, the thickness of the hafnium oxide interface layer is 25~100 nm (e.g., 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 nm), preferably 50~100 nm (e.g., 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 nm); and / or the thickness of the pyrolytic carbon-hafnium oxide composite interface layer is 0.2~1 μm (e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 μm).

[0025] According to some preferred embodiments, the thickness of the hafnium carbide coating is 0.5~5μm; and / or the thickness of the hafnium oxide coating is 50~200nm, preferably 150~200nm. In this invention, it is preferred that the thickness of the hafnium carbide coating is controlled to be 0.5~5μm and the thickness of the hafnium oxide coating is 50~200nm, thereby achieving an optimized combination of the thicknesses of the hafnium carbide and hafnium oxide coatings, which significantly improves the mechanical properties of the material under high temperature conditions. This invention finds that the hafnium carbide coating serves as the main load-bearing and high-temperature protective layer, while the thin and uniform hafnium oxide coating, by forming a dense oxidation barrier, inhibits oxidation and interfacial diffusion, thereby improving the oxidation resistance and interfacial stability of the material under extreme high temperatures. Meanwhile, the matching thickness of the hafnium oxide coating and the hafnium carbide coating effectively alleviates the interfacial stress concentration caused by the difference in thermal expansion, reduces the generation and propagation of microcracks, and thus comprehensively improves the high-temperature strength and long-term thermal stability of the composite material, achieving excellent mechanical properties and reliability of the material under ultra-high temperature conditions. If the hafnium oxide coating is too thin, its dense oxide barrier effect is insufficient, and oxygen can easily penetrate into the hafnium carbide layer at high temperatures, causing oxidation and interfacial diffusion, which can easily lead to the generation of microcracks. If the hafnium oxide coating is too thick, due to the large difference in its thermal expansion coefficient with that of hafnium carbide, the interfacial stress concentration at high temperatures can easily lead to microcracks or peeling.

[0026] According to some preferred embodiments, in step (2) and / or step (5): the precursor used in the atomic layer deposition process is tetramethylethylamine hafnium and ultrapure water, and the temperature of the atomic layer deposition reaction is 220~300℃; in step (2), the number of deposition cycles is 100~2000 times (e.g., 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 or 2000 times); in step (5), the number of deposition cycles is 200~4000 times (e.g., 200, 500, 800, 1000, 1500, 2000, 2500, 3000, 3500 or 4000 times); a single deposition cycle is: The pulse duration of the tetramethylethylamine hafnium is 0.3~0.6s, and the argon purging time is 1~3s; the pulse duration of the ultrapure water is 0.1~0.3s, and the argon purging time is 1~3s.

[0027] According to some preferred embodiments, in step (2) and / or step (5): the ultra-fast annealing process is to heat the temperature at a rate of 25~50℃ / s (e.g., 25℃ / s, 30℃ / s, 35℃ / s, 40℃ / s, 45℃ / s or 50℃ / s) for 15~60s (e.g., 15, 20, 35, 30, 35, 40, 45, 50, 55 or 60s) to 650~850℃ (e.g., 650℃, 700℃, 750℃, 800℃ or 850℃) and hold it for 40~100s (e.g., 40, 50, 60, 70, 80, 90 or 100s).

[0028] The key to step (2) of this invention lies in using atomic layer deposition (ALD) to prepare a dense hafnium oxide interface layer on the surface of pyrolytic carbon, and simultaneously performing a suitable ultra-fast annealing process to promote the crystallization of the ceramic interface layer and enhance the bonding force between the hafnium oxide interface layer and the pyrolytic carbon, thereby fully protecting the carbon fibers. Although existing technologies involve rapid high-temperature sintering when preparing ceramic matrix composites, due to differences in material systems and interface structures, the parameters of existing technologies are not applicable to the hafnium oxide interface layer system obtained by ALD in this invention, nor can they provide guidance for the selection of ultra-fast annealing parameters in this invention. This invention reveals that, in forming a pyrolytic carbon-hafnium oxide composite interface layer, appropriate heating rates, annealing temperatures, and holding times can enhance the bonding force between the hafnium oxide interface layer and the pyrolytic carbon, while preventing the hafnium oxide interface layer from cracking and failing. When the heating rate is below 25°C / s, the temperature is above 850°C, or the holding time is above 100s, the hafnium oxide interface layer will crack and fail to provide good protection. When the heating rate is above 50°C / s, the temperature is below 650°C, or the holding time is below 40s, the bonding force between the hafnium oxide interface layer and the pyrolytic carbon interface layer will be weak, and the degree of hafnium oxide crystallinity will be low, leading to rapid peeling and failure under an oxidizing atmosphere, and the carbon fiber will be rapidly oxidized and its performance will deteriorate.

[0029] According to some preferred embodiments, in step (2) and / or step (5), after holding at 650~850℃ for 40~100s, the temperature is reduced to room temperature at a cooling rate of 5~15℃ / s; in this invention, room temperature refers to room temperature of 15~35℃; in step (2) of this invention, it is preferred to control the cooling rate within the range of 5~15℃ / s. This cooling rate can achieve an optimized balance between material thermal expansion matching, interfacial bonding force and hafnium oxide crystal structure stability. Through this reasonably selected cooling rate, thermal stress concentration can be effectively alleviated, interfacial cracking can be prevented, and the density and continuity of the hafnium oxide interfacial layer can be maintained, thereby enhancing the bonding force between the hafnium oxide interfacial layer and pyrolytic carbon. Compared with the prior art, the cooling rate and ultra-fast annealing parameters of the present invention are optimized for the atomic layer deposition hafnium oxide interface layer system. This ensures the stability of the interface structure and fully leverages the role of the pyrolytic carbon-hafnium oxide composite interface layer in protecting carbon fibers and improving the high-temperature service reliability of composite materials. As a result, a composite interface structure with high bonding strength and excellent oxidation resistance, which is difficult to achieve with the prior art, is obtained.

[0030] According to some specific implementation methods, step (2) includes the following sub-steps: (a) The porous carbon / carbon composite matrix is ​​placed in the atomic layer deposition reaction chamber (atomic layer deposition equipment cavity), and the temperature of the atomic layer deposition reaction chamber is set to 220~300℃; (b) Heating tetramethylethylaminohafnium at a temperature of 70~100℃; (c) Tetramethylethylamine hafnium is introduced into the atomic layer deposition reaction chamber in a pulsed manner and chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix. Excess tetramethylethylamine hafnium is purged out of the atomic layer deposition reaction chamber with argon gas. In step (c), the pulse time of the tetramethylethylamine hafnium is 0.3~0.6s, and the argon purging time is 1~3s. (d) Ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulsed manner and reacts with the tetramethylethylamine hafnium that is chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix in step (c). Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas. In step (d), the pulse time of the ultrapure water is 0.1~0.3s and the argon purging time is 1~3s. (e) Repeat steps (c) and (d) 100 to 2000 times in sequence; wherein, steps (c) and (d) constitute one deposition cycle, and steps (c) and (d) are repeated 100 to 2000 times in sequence, that is, the number of deposition cycles is 100 to 2000. (f) After step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C. The material is removed from the atomic layer deposition reaction chamber and placed in an argon atmosphere. The temperature is increased at a rate of 25-50°C / s, for example, to 650-850°C in 15-60s. The temperature is held for 40-100s for ultra-fast annealing to promote the crystallization of the hafnium oxide interface layer and enhance the bonding force between the hafnium oxide interface layer and the pyrolytic carbon, so as to fully protect the carbon fiber. After holding at 650-850°C for 40-100s, the temperature is reduced to room temperature at a rate of 5-15°C / s to complete the preparation of the composite matrix containing the pyrolytic carbon-hafnium oxide composite interface layer.

[0031] The key to step (5) of this invention lies in using atomic layer deposition (ALD) to prepare a dense hafnium oxide coating on the surface of a hafnium carbide coating, and simultaneously performing a suitable ultra-fast annealing process to promote the crystallization of the hafnium oxide coating and enhance the bonding force between the hafnium oxide coating and the hafnium carbide coating, thereby fully leveraging the protective effect on the substrate. Although existing technologies involve rapid high-temperature sintering when preparing ceramic matrix composites, due to differences in material systems and coating structures, the parameters of existing technologies are not applicable to the hafnium oxide coating system obtained by ALD in this invention, nor can they provide guidance for the selection of ultra-fast annealing parameters in this invention. This invention reveals that, during the formation of a hafnium carbide-hafnium oxide composite coating, appropriate heating rates, annealing temperatures, and holding times can enhance the bonding strength between the hafnium oxide and hafnium carbide coatings while preventing cracking and failure of the hafnium oxide coating. When the heating rate is below 25°C / s, the temperature is above 850°C, or the holding time is above 100s, the hafnium oxide coating will crack and fail to provide good protection. When the heating rate is above 50°C / s, the temperature is below 650°C, or the holding time is below 40s, the bonding strength between the hafnium oxide and hafnium carbide coatings will be weak, and the hafnium oxide will have a low degree of crystallinity, leading to rapid peeling and failure under an oxidizing atmosphere. Oxygen will quickly penetrate into the matrix, causing the carbon fibers to be oxidized and their performance to deteriorate.

[0032] According to some preferred embodiments, in step (5) of the present invention, the cooling rate is preferably controlled within the range of 5~15℃ / s. This cooling rate can achieve an optimized balance between material thermal expansion matching, interfacial bonding force, and hafnium oxide crystal structure stability. Through this reasonably selected cooling rate, thermal stress concentration can be effectively alleviated, interfacial cracking can be prevented, and the density and continuity of the hafnium oxide coating can be maintained, thereby enhancing the bonding force between the hafnium oxide coating and the hafnium carbide coating. Compared with the prior art, the cooling rate and ultra-fast annealing parameters of the present invention are optimized for the atomic layer deposition hafnium oxide coating system, which not only ensures the stability of the coating structure, but also fully utilizes the role of the hafnium carbide-hafnium oxide composite coating in protecting the composite material and improving the high-temperature service reliability of the composite material, thereby obtaining a composite coating structure with high bonding force and excellent oxidation resistance that is difficult to achieve with the prior art.

[0033] According to some specific implementation methods, step (5) includes the following sub-steps: S1. The hafnium-based ultra-high temperature ceramic matrix composite material matrix is ​​placed in an atomic layer deposition reaction chamber (atomic layer deposition equipment cavity), and the temperature of the atomic layer deposition reaction chamber is set to 220~300℃; S2. Heat tetramethylethylaminohafnium at a temperature of 70~100℃; S3. Tetramethylethylamine hafnium is introduced into the atomic layer deposition reaction chamber in a pulsed manner and chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite matrix. Excess tetramethylethylamine hafnium is purged out of the atomic layer deposition reaction chamber with argon gas. In step S3, the pulse time of the tetramethylethylamine hafnium is 0.3~0.6s, and the argon purging time is 1~3s. S4. Ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulsed manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix in step S3 to form a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas. In step S4, the pulse time of the ultrapure water is 0.1~0.3s, and the argon gas purging time is 1~3s. S5 repeats steps S3 and S4 200 to 4000 times; wherein, steps S3 and S4 constitute one deposition cycle, and steps S3 and S4 are repeated 200 to 4000 times, that is, the number of deposition cycles is 200 to 4000. S6. After step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C. The material is removed from the atomic layer deposition reaction chamber and placed in an argon atmosphere. The heating rate is 25-50°C / s, for example, heating to 650-850°C in 15-60s and holding for 40-100s for ultra-fast annealing to promote the crystallization of the hafnium oxide coating and improve the bonding force between the hafnium oxide coating and the hafnium carbide coating. After holding at 650-850°C for 40-100s, the temperature is reduced to room temperature at a cooling rate of 5-15°C / s to complete the preparation of the high-performance hafnium-based ultra-high temperature ceramic matrix composite material.

[0034] According to some preferred embodiments, in step (3): the pyrolysis temperature is 1200~1450℃.

[0035] According to some preferred embodiments, in step (4): when preparing the hafnium carbide coating, the temperature of chemical vapor deposition is 1100~1400℃, the pressure is 0.1~50Pa, and / or the time is 1~2h.

[0036] According to some preferred embodiments, the high-performance hafnium-based ultra-high temperature ceramic matrix composite material comprises a hafnium carbide-hafnium oxide composite coating; and / or the high-performance hafnium-based ultra-high temperature ceramic matrix composite material has a tensile strength greater than 170 MPa at 2000°C in air atmosphere.

[0037] In a second aspect, the present invention provides a high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared by the preparation method described in the first aspect of the present invention; the hafnium-based ultra-high temperature ceramic matrix composite material prepared by the present invention has the advantage of high performance, manifested in a significant improvement in mechanical properties under high temperature and oxygen environment.

[0038] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments. The present invention may have many other embodiments, and those skilled in the art can make various corresponding changes and modifications based on the present invention without departing from its spirit and essence. However, all such corresponding changes and modifications should fall within the scope of protection of the appended claims. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials, reagents, etc., used in the following embodiments can be obtained commercially or synthesized by existing methods.

[0039] The preparation of the oxygen-free hafnium carbide ceramic precursor involved in the following embodiments and comparative examples of the present invention is as follows: The three-necked flask was evacuated multiple times and filled with argon to replace the air. Tetra(diethylamino)hafnium was added, followed by diallylamine. The mixture was stirred and reacted at 30°C in an argon atmosphere for 18 hours. Afterward, the reactants were distilled under reduced pressure to remove low-boiling-point substances, yielding a liquid oxygen-free hafnium carbide ceramic precursor. The molar ratio of tetra(diethylamino)hafnium to diallylamine was 1:1.

[0040] Example 1 (1) Provide a porous carbon / carbon composite matrix: the density of the carbon fiber preform is 0.15 g / cm³. 3 A pyrolytic carbon interface layer with a density of 0.2 g / cm³ was prepared by depositing the layer on the carbon fiber surface of the carbon fiber preform using chemical vapor deposition, with a thickness of 2 mm. 3 A porous carbon / carbon composite matrix; wherein the thickness of the pyrolytic carbon interface layer is 0.4 μm.

[0041] (2) Preparation of pyrolytic carbon-hafnium oxide composite interface layer: (a) The porous carbon / carbon composite matrix is ​​placed in an atomic layer deposition reaction chamber, and the temperature of the atomic layer deposition reaction chamber is set to 240℃; (b) Tetramethylethylamine hafnium is heated to 80℃; (c) Tetramethylethylamine hafnium is introduced into the atomic layer deposition reaction chamber in a pulse manner and chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix, and excess tetramethylethylamine hafnium is purged out of the atomic layer deposition reaction chamber with argon gas; in step (c), the pulse time of the tetramethylethylamine hafnium is 0.5s, and the argon purging time is 2s; (d) Ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulse manner and reacts with the tetramethylamine hafnium chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix in step (c). Ethylamine hafnium undergoes a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber using argon gas. In step (d), the pulse time of the ultrapure water is 0.2 s, and the argon purging time is 2 s. (e) Steps (c) and (d) are repeated 1000 times. (f) After step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C. The material is removed from the atomic layer deposition reaction chamber and placed in an argon atmosphere. The temperature is increased to 700°C at a rate of 35°C / s and held for 50 s for ultra-rapid annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer. The thickness of the hafnium oxide interface layer is 50 nm.

[0042] (3) Preparation of hafnium-based ultra-high temperature ceramic matrix composite material matrix: Using liquid oxygen-free hafnium carbide ceramic precursor as reactant, the composite material matrix containing pyrolytic carbon-hafnium oxide composite interface layer is reacted with the composite material matrix by impregnation pyrolysis method to prepare hafnium-based ultra-high temperature ceramic matrix composite material matrix; wherein, a total of 10 rounds of impregnation, curing and pyrolysis treatment are carried out. Each impregnation is first vacuum impregnated for 1 hour at a pressure of 200 Pa, and then pressure impregnated for 1 hour at a pressure of 2 MPa. The curing temperature is 280℃ and the curing time is 2 hours. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1200℃ and the pyrolysis time is 2 hours. The pyrolysis is carried out in an argon atmosphere.

[0043] (4) Preparation of hafnium carbide coating: A hafnium carbide coating with a thickness of 3 μm was prepared on the surface of a hafnium-based ultra-high temperature ceramic matrix composite substrate by chemical vapor deposition. The chemical vapor deposition was carried out under a pressure of 20 Pa, with hafnium tetrachloride, propane and hydrogen as the reaction source and argon as the carrier gas. The flow ratio of hafnium tetrachloride, propane, hydrogen and argon was 1:6:6:15, and the temperature of chemical vapor deposition was 1200 °C.

[0044] (5) Preparation of hafnium oxide coating: S1, placing the hafnium-based ultra-high temperature ceramic matrix composite material matrix in an atomic layer deposition reaction chamber, setting the temperature of the atomic layer deposition reaction chamber to 240℃; S2, heating tetramethylethylamine hafnium to 80℃; S3, allowing tetramethylethylamine hafnium to enter the atomic layer deposition reaction chamber in a pulsed manner and chemically adsorbing it onto the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix, and using argon gas to purge excess tetramethylethylamine hafnium from the atomic layer deposition reaction chamber; in step S3, the tetramethylethylamine hafnium... The pulse duration of the amine hafnium is 0.5 s, and the argon purging time is 2 s; S4, ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulsed manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix in step S3 to undergo a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas; in step S4, the pulse duration of the ultrapure water is 0.2 s, and the argon purging time is 2 s; S5, steps S3 and S4 are repeated sequentially. 3000 times; S6. After step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is taken out from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The temperature is increased to 700°C at a rate of 35°C / s and held for 50s for ultra-fast annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a high-performance hafnium-based ultra-high temperature ceramic matrix composite material; wherein the thickness of the hafnium oxide coating is 150nm.

[0045] Tensile strength test in air at 2000℃: The mechanical properties of the high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high-temperature oxygen environment. The tensile strength was 187 MPa in air at 2000℃.

[0046] Example 2 Example 2 is basically the same as Example 1, except that: (1) Provide a porous carbon / carbon composite matrix: the density of the carbon fiber preform is 0.15 g / cm³. 3 A pyrolytic carbon interface layer with a density of 0.2 g / cm³ was prepared by depositing the layer on the carbon fiber surface of the carbon fiber preform using chemical vapor deposition, with a thickness of 4 mm. 3 Porous carbon / carbon composite matrix.

[0047] Tensile strength test in air at 2000℃: The mechanical properties of the high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high-temperature oxygen environment. The tensile strength was 172 MPa in air at 2000℃.

[0048] Example 3 Example 3 is basically the same as Example 1, except that: (1) Provide a porous carbon / carbon composite matrix: the density of the carbon fiber preform is 0.15 g / cm³. 3 A pyrolytic carbon interface layer with a density of 0.2 g / cm³ was prepared by depositing the layer on the carbon fiber surface of the carbon fiber preform using chemical vapor deposition with a thickness of 8 mm. 3 Porous carbon / carbon composite matrix.

[0049] Tensile strength test in air at 2000℃: The mechanical properties of the high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high-temperature oxygen environment. The tensile strength was 93 MPa in air at 2000℃.

[0050] Example 4 Example 4 is basically the same as Example 1, except that: (1) Provide a porous carbon / carbon composite matrix: the density of the carbon fiber preform is 0.15 g / cm³. 3 A pyrolytic carbon interface layer with a thickness of 0.5 mm was deposited on the carbon fiber surface of the carbon fiber preform using chemical vapor deposition, resulting in a density of 0.2 g / cm³. 3 Porous carbon / carbon composite matrix.

[0051] Tensile strength test in air at 2000℃: The mechanical properties of the high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high-temperature oxygen environment. The tensile strength was 77 MPa in air at 2000℃.

[0052] Example 5 Example 5 is basically the same as Example 1, except that: (2) Preparation of pyrolytic carbon-hafnium oxide composite interface layer: (a) The porous carbon / carbon composite matrix is ​​placed in an atomic layer deposition reaction chamber, and the temperature of the atomic layer deposition reaction chamber is set to 240℃; (b) Tetramethylethylamine hafnium is heated to 80℃; (c) Tetramethylethylamine hafnium is introduced into the atomic layer deposition reaction chamber in a pulse manner and chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix, and excess tetramethylethylamine hafnium is purged out of the atomic layer deposition reaction chamber with argon gas; in step (c), the pulse time of the tetramethylethylamine hafnium is 0.5s, and the argon purging time is 2s; (d) Ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulse manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix in step (c). Amine hafnium undergoes a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber using argon gas. In step (d), the pulse time of the ultrapure water is 0.2 s, and the argon purging time is 2 s. (e) Steps (c) and (d) are repeated 2000 times. (f) After step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C. The material is removed from the atomic layer deposition reaction chamber and placed in an argon atmosphere. The temperature is increased to 700°C at a rate of 35°C / s and held for 50 s for ultra-rapid annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer. The thickness of the hafnium oxide interface layer is 100 nm.

[0053] Tensile strength test in air at 2000℃: The mechanical properties of the high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high-temperature oxygen environment. The tensile strength was 213 MPa in air at 2000℃.

[0054] As can be seen from Examples 1-5 above, compared to Example 1, in Example 2, the thickness of the carbon fiber preform was increased from 2 mm to 4 mm, which prolonged the molecular diffusion distance of tetramethylethylamine hafnium and affected the uniformity of hafnium oxide interface layer deposition. Therefore, the tensile strength under high temperature and oxygen conditions decreased from 187 MPa to 172 MPa. Compared to Example 1, in Example 3, the thickness of the carbon fiber preform was increased from 2 mm to 8 mm, which significantly prolonged the molecular diffusion distance of tetramethylethylamine hafnium and significantly affected the uniformity of hafnium oxide interface layer deposition. Therefore, the tensile strength under high temperature and oxygen conditions decreased from 187 MPa to 93 MPa. Compared to Example 1, in Example 4, the thickness of the carbon fiber preform was reduced from 2 mm to 0.5 mm. Although the molecular diffusion distance of tetramethylethylamine hafnium was significantly shortened and the uniformity of the hafnium oxide interface layer deposition was improved, the self-support of the carbon fiber preform was insufficient, making it more prone to deformation during the composite process, thus affecting the mechanical properties. Therefore, the tensile strength under high temperature and oxygen conditions decreased from 187 MPa to 77 MPa. Compared to Example 1, in Example 5, the number of cycles was increased from 1000 to 2000 when preparing the hafnium oxide interface layer, and the thickness of the hafnium oxide interface layer was increased from 50 nm to 100 nm. The protective effect of the carbon fiber was significantly improved, thus the tensile strength under high temperature and oxygen conditions increased from 187 MPa to 213 MPa.

[0055] Examples 6-12 The specific process parameters of Examples 6-12 and the performance indicators of the final hafnium-based ultra-high temperature ceramic matrix composites are shown in Table 1. The other preparation processes are the same as those in Example 1.

[0056] Table 1 In the above embodiments 6 to 12, the ultra-fast annealing parameters in step (f) and step S6 are the same.

[0057] As shown in Table 1 above, compared to Example 1, in Example 6, the number of cycles in preparing the hafnium oxide interface layer was reduced from 1000 to 600, and the thickness of the hafnium oxide interface layer was reduced from 50 nm to 30 nm. This weakened the protective effect on the carbon fiber, resulting in a decrease in tensile strength from 187 MPa to 128 MPa under high-temperature aerobic conditions. Compared to Example 1, in Example 7, the heating rate during ultra-fast annealing was increased from 35 °C / s to 45 °C / s. This enhanced the bonding strength between the hafnium oxide interface layer and the pyrolytic carbon interface layer, as well as between the hafnium oxide coating and the hafnium carbide coating. The protective effect of the pyrolytic carbon-hafnium oxide composite interface layer on the carbon fiber was improved, and the protective effect of the ceramic composite coating on the substrate was also enhanced. Therefore, the tensile strength under high-temperature aerobic conditions increased from 187 MPa to 196 MPa. Compared to Example 1, in Example 8, the heating rate during ultra-rapid annealing was reduced from 35℃ / s to 20℃ / s. This weakened the bonding strength between the hafnium oxide interface layer and the pyrolytic carbon interface layer, as well as between the hafnium oxide coating and the hafnium carbide coating. Consequently, the protective effect of the pyrolytic carbon-hafnium oxide composite interface layer on the carbon fibers was reduced, and the protective effect of the ceramic composite coating on the substrate was also reduced. Therefore, the tensile strength under high-temperature aerobic conditions decreased from 187 MPa to 149 MPa. Compared to Example 1, in Example 9, the heating rate during ultra-rapid annealing was increased from 35℃ / s to 80℃ / s. This resulted in weaker bonding strength between the hafnium oxide interface layer and the pyrolytic carbon interface layer, as well as between the hafnium oxide coating and the hafnium carbide coating. The protective effect of the pyrolytic carbon-hafnium oxide composite interface layer on the carbon fibers was also reduced, and the protective effect of the ceramic composite coating on the substrate was further decreased. Consequently, the tensile strength under high-temperature aerobic conditions decreased from 187 MPa to 116 MPa. Compared to Example 1, in Example 10, the processing temperature was increased from 700℃ to 800℃ during ultra-rapid annealing. This improved the crystallinity of hafnium oxide, the bonding strength between the hafnium oxide interface layer and the pyrolytic carbon interface layer, and the bonding strength between the hafnium oxide coating and the hafnium carbide coating. The protective effect of the pyrolytic carbon-hafnium oxide composite interface layer on the carbon fibers was enhanced, and the protective effect of the ceramic composite coating on the substrate was strengthened. Therefore, the tensile strength under high temperature and oxygen conditions increased from 187MPa to 204MPa. Compared to Example 1, in Example 11, the holding time was extended from 50s to 90s during ultra-rapid annealing. This enhanced the bonding strength between the hafnium oxide interface layer and the pyrolytic carbon interface layer, as well as the bonding strength between the hafnium oxide coating and the hafnium carbide coating. The protective effect of the pyrolytic carbon-hafnium oxide composite interface layer on the carbon fibers was improved, and the protective effect of the ceramic composite coating on the substrate was strengthened. Therefore, the tensile strength under high temperature and oxygen conditions increased from 187MPa to 218MPa. Compared to Example 1, in Example 12, the number of cycles was increased from 3000 to 4000 when preparing the hafnium oxide coating, and the thickness of the hafnium oxide interface layer was increased from 150 nm to 200 nm. The protective effect of the ceramic composite coating was significantly improved, and the tensile strength under high temperature and oxygen environment was increased from 187 MPa to 237 MPa.

[0058] Example 13 Example 13 is basically the same as Example 1, except that: In steps (f) and S6, after holding the ultra-fast annealing treatment at 700°C for 50 seconds, the temperature is reduced to room temperature at a rate of 5°C / min.

[0059] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 89 MPa in air at 2000℃.

[0060] Example 14 Example 14 is basically the same as Example 1, except that: In steps (f) and S6, after holding the ultra-fast annealing treatment at 700°C for 50 seconds, the temperature is reduced to room temperature at a cooling rate of 20°C / s.

[0061] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 101 MPa in air at 2000℃.

[0062] Example 15 Example 15 is basically the same as Example 1, except that: In steps (f) and S6, after holding the ultra-fast annealing treatment at 700°C for 50 seconds, the temperature is reduced to room temperature at a cooling rate of 50°C / s.

[0063] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 93 MPa in air at 2000℃.

[0064] Example 16 Example 16 is basically the same as Example 1, except that: (5) Preparation of hafnium oxide coating: S1, placing the hafnium-based ultra-high temperature ceramic matrix composite material matrix in an atomic layer deposition reaction chamber, setting the temperature of the atomic layer deposition reaction chamber to 240℃; S2, heating tetramethylethylamine hafnium to 80℃; S3, allowing tetramethylethylamine hafnium to enter the atomic layer deposition reaction chamber in a pulsed manner and chemically adsorbing it onto the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix, and using argon gas to purge excess tetramethylethylamine hafnium from the atomic layer deposition reaction chamber; in step S3, the tetramethylethylamine hafnium... The pulse duration of the amine hafnium is 0.5 s, and the argon purging time is 2 s; S4, ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulsed manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix in step S3 to undergo a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas; in step S4, the pulse duration of the ultrapure water is 0.2 s, and the argon purging time is 2 s; S5, steps S3 and S4 are repeated sequentially. 400 times; S6. After step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is taken out from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The temperature is increased to 700°C at a rate of 35°C / s and held for 50s for ultra-fast annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a high-performance hafnium-based ultra-high temperature ceramic matrix composite material; wherein the thickness of the hafnium oxide coating is 20nm.

[0065] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 98 MPa in air at 2000℃.

[0066] Example 17 Example 17 is basically the same as Example 1, except that: In step (f), after step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is removed from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The heating rate is 35°C / s, the temperature is raised to 550°C, and the holding time is 50s for ultra-fast annealing. Then, the temperature is cooled to room temperature at a cooling rate of 10°C / s to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer; wherein, the thickness of the hafnium oxide interface layer is 50nm.

[0067] In step S6, after step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is removed from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The temperature is increased to 550°C at a rate of 35°C / s and held for 50s for ultra-fast annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a hafnium-based ultra-high temperature ceramic matrix composite material. The thickness of the hafnium oxide coating is 150nm.

[0068] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 125 MPa in air at 2000℃.

[0069] Example 18 Example 18 is basically the same as Example 1, except that: In step (f), after step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is removed from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The heating rate is 35°C / s, the temperature is raised to 950°C, and the holding time is 50s for ultra-fast annealing. Then, the temperature is cooled to room temperature at a cooling rate of 10°C / s to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer; wherein the thickness of the hafnium oxide interface layer is 50nm.

[0070] In step S6, after step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is removed from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The temperature is increased to 950°C at a rate of 35°C / s and held for 50s for ultra-fast annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a hafnium-based ultra-high temperature ceramic matrix composite material. The thickness of the hafnium oxide coating is 150nm.

[0071] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 94 MPa in air at 2000℃.

[0072] Example 19 Example 19 is basically the same as Example 1, except that: In step (f), after step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is removed from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The heating rate is 35°C / s, the temperature is raised to 700°C, and the holding time is 180s for ultra-fast annealing. Then, the temperature is cooled to room temperature at a cooling rate of 10°C / s to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer; wherein, the thickness of the hafnium oxide interface layer is 50nm.

[0073] In step S6, after step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is removed from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The temperature is increased to 700°C at a rate of 35°C / s and held for 180s for ultra-fast annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a hafnium-based ultra-high temperature ceramic matrix composite material. The thickness of the hafnium oxide coating is 150nm.

[0074] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this embodiment were tested in a high temperature and oxygen environment. The tensile strength was 82 MPa in air at 2000℃.

[0075] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that: (2) Preparation of pyrolytic carbon-hafnium carbide composite interface layer: (a) The porous carbon / carbon composite matrix is ​​placed in an atomic layer deposition reaction chamber, and the temperature of the atomic layer deposition reaction chamber is set to 240℃; (b) Tetramethylethylamine hafnium is heated to 80℃; (c) Tetramethylethylamine hafnium is introduced into the atomic layer deposition reaction chamber in a pulse manner and chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix, and excess tetramethylethylamine hafnium is purged out of the atomic layer deposition reaction chamber with argon gas; in step ( In step (c), the pulse duration of the tetramethylethylamine hafnium is 0.5 s, and the argon purging time is 2 s; (d) ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulsed manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix in step (c). Excess ultrapure water and byproducts generated after the deposition reaction are then purged out of the atomic layer deposition reaction chamber using argon gas; in step (d), the pulse duration of the ultrapure water is 0.2 s, and the argon purging time is... 2s; (e) Repeat steps (c) and (d) 1000 times; (f) After step (e) is completed, lower the temperature of the atomic layer deposition reaction chamber to below 60°C, remove the material from the atomic layer deposition reaction chamber, and place the material in an argon atmosphere. Heat the material to 700°C at a rate of 35°C / s, hold for 50s, and perform ultra-fast annealing. Then cool the material to room temperature at a rate of 10°C / s to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer; The thickness of the hafnium oxide interface layer is 50 nm; (h) the composite matrix containing the pyrolytic carbon-hafnium oxide composite interface layer is subjected to carbothermal reduction to obtain a composite matrix containing the pyrolytic carbon-hafnium carbide composite interface layer; wherein, the carbothermal reduction is: under the protection of inert gas argon, the temperature is raised to 1500℃ (the heating rate is 5℃ / min), and the temperature is kept constant at 1500℃ for 120 minutes to carry out the carbothermal reduction reaction, so that the hafnium oxide interface layer is converted into the hafnium carbide interface layer, and finally the temperature is lowered to room temperature at a rate of 5℃ / min.

[0076] In this comparative example, the composite matrix containing the pyrolytic carbon-hafnium carbide composite interface layer obtained in step (2) is used to replace the composite matrix containing the pyrolytic carbon-hafnium oxide composite interface layer in Example 1 for subsequent steps (3), (4) and (5).

[0077] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 106 MPa in air at 2000℃.

[0078] Comparative Example 2 ① A pyrolytic carbon interface layer with a density of 0.5 g / cm³ was deposited on the surface of the carbon fibers contained in the carbon fiber preform using chemical vapor deposition. 3The porous C / C matrix; the carbon fiber preform is a needle-punched preform with a pyrolytic carbon interface layer thickness of 1.0 μm.

[0079] ② Prepare a 0.1 mol / L Hf(NO3)4 aqueous solution. Immerse the porous C / C matrix obtained in step ① in the Hf(NO3)4 aqueous solution under pressure for 240 min at a pressure of 0.3 MPa. Dry it in an oven at 80℃ for 240 min. Then place it in a sintering apparatus and heat it to 600℃ under the protection of inert argon gas (heating rate of 5℃ / min). Hold it at 600℃ for 120 min and then cool it to room temperature at a rate of 5℃ / min.

[0080] ③ Repeat step ② 9 times to obtain a first modified matrix on the surface of carbon fiber, which is sequentially coated with a pyrolytic carbon interface layer and a metal oxide layer, wherein the thickness of the metal oxide layer (hafnium oxide layer) is 200 nm.

[0081] ④ The first modified matrix is ​​placed in a high-temperature device and heated to 1400℃ (heating rate of 5℃ / min) under the protection of inert argon gas. It is kept at 1400℃ for 120 minutes to undergo a carbothermic reduction reaction, which transforms the hafnium oxide layer into a hafnium carbide layer. The matrix is ​​then cooled to room temperature at a rate of 5℃ / min to obtain a second modified matrix with a pyrolytic carbon interface layer and a metal carbide layer (hafnium carbide layer) coated on the carbon fiber surface. The thickness of the metal carbide layer (hafnium carbide) is 200nm, and the thickness of the C / HfC composite interface layer is 1.2μm.

[0082] ⑤ Using hafnium carbide ceramic precursor as reactant, a carbon fiber-toughened ceramic matrix composite material is prepared by reacting it with the second modified matrix through an impregnation pyrolysis method; wherein, the hafnium carbide ceramic precursor uses xylene as solvent, has a solid content of 40%, a viscosity of 70 mPa·s, and undergoes 10 rounds of impregnation, curing, and pyrolysis treatment. Each impregnation is first vacuum impregnated for 1 hour at a pressure of 200 Pa, followed by pressure impregnation for 1 hour at a pressure of 2 MPa. The curing temperature is 280℃ and the curing time is 2 hours each time. The pyrolysis temperature is 1550℃ and the pyrolysis time is 2 hours each time.

[0083] Tensile strength test in air at 2000℃: The mechanical properties of the carbon fiber toughened ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 86 MPa in air at 2000℃.

[0084] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that: (2) Preparation of pyrolytic carbon-hafnium oxide composite interface layer: ① Prepare a 0.1 mol / L Hf(NO3)4 aqueous solution, immerse the porous carbon / carbon composite matrix in the Hf(NO3)4 aqueous solution under pressure for 240 min at a pressure of 0.3 MPa, dry it in an oven at 80℃ for 240 min, and then place it in a sintering apparatus. Under the protection of inert argon gas, heat it to 600℃ (heating rate of 5℃ / min), hold it at 600℃ for 120 min, and then cool it to room temperature at a rate of 5℃ / min. ② Repeat step ① multiple times until the hafnium oxide layer thickness is 50 nm to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer.

[0085] (5) Preparation of hafnium oxide coating: ① Prepare a 0.1 mol / L Hf(NO3)4 aqueous solution, immerse the hafnium-based ultra-high temperature ceramic matrix composite matrix with hafnium carbide coating in the Hf(NO3)4 aqueous solution under pressure for 240 min at a pressure of 0.3 MPa, dry in an oven at 80℃ for 240 min, then place it in a sintering apparatus, heat to 600℃ under inert argon gas protection (heating rate of 5℃ / min), hold at 600℃ for 120 min, and cool to room temperature at a rate of 5℃ / min. ② Repeat step ① multiple times until the thickness of the hafnium oxide coating is 150 nm to obtain the hafnium-based ultra-high temperature ceramic matrix composite material.

[0086] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 84 MPa in air at 2000℃.

[0087] Comparative Example 4 (1) Same as step (1) in Example 1.

[0088] (2) Preparation of hafnium-based ultra-high temperature ceramic matrix composite material matrix: Using liquid oxygen-free hafnium carbide ceramic precursor as reactant, the matrix is ​​prepared by reacting with the porous carbon / carbon composite material matrix through impregnation pyrolysis method; wherein, a total of 10 rounds of impregnation, curing and pyrolysis treatment are carried out. Each impregnation is first vacuum impregnated for 1 hour at a pressure of 200 Pa, and then pressure impregnated for 1 hour at a pressure of 2 MPa. The curing temperature is 280℃ and the curing time is 2 hours. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1200℃ and the pyrolysis time is 2 hours. The pyrolysis is carried out in an argon atmosphere.

[0089] (3) Preparation of hafnium carbide coating: A hafnium carbide coating with a thickness of 3 μm was prepared on the surface of the hafnium-based ultra-high temperature ceramic matrix composite matrix by chemical vapor deposition, thus obtaining the hafnium-based ultra-high temperature ceramic matrix composite matrix; wherein, the chemical vapor deposition was carried out under a pressure of 20 Pa, with hafnium tetrachloride, propane and hydrogen as the reaction source, and argon as the carrier gas, the flow ratio of hafnium tetrachloride, propane, hydrogen and argon was 1:6:6:15, and the temperature of chemical vapor deposition was 1200℃. Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 38 MPa in air at 2000℃.

[0090] Comparative Example 5 Comparative Example 5 is basically the same as Example 1, except that: (2) Preparation of pyrolytic carbon-hafnium oxide composite interface layer: (a) The porous carbon / carbon composite matrix is ​​placed in an atomic layer deposition (ALD) reaction chamber, and the temperature of the ALD reaction chamber is set to 240°C; (b) Tetramethylethylamine hafnium is heated to 80°C; (c) Tetramethylethylamine hafnium is introduced into the ALD reaction chamber in a pulsed manner and chemically adsorbed onto the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix, and excess tetramethylethylamine hafnium is purged out of the ALD reaction chamber with argon gas; in step (c), the pulse time of the tetramethylethylamine hafnium is 0.5 s, and the argon purging time is 2 s; (d) Ultrapure water is introduced into the ALD reaction chamber in a pulsed manner. In the atomic layer deposition chamber, a deposition reaction is carried out with tetramethylethylamine hafnium oxide that is chemically adsorbed on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix in step (c). Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas. In step (d), the pulse time of the ultrapure water is 0.2s and the argon purging time (standing time) is 2s. (e) Steps (c) and (d) are repeated 1000 times. (f) After step (e) is completed, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer. The thickness of the hafnium oxide interface layer is 50nm.

[0091] (5) Preparation of hafnium oxide coating: S1, placing the hafnium-based ultra-high temperature ceramic matrix composite material matrix in an atomic layer deposition reaction chamber, setting the temperature of the atomic layer deposition reaction chamber to 240℃; S2, heating tetramethylethylamine hafnium to 80℃; S3, allowing tetramethylethylamine hafnium to enter the atomic layer deposition reaction chamber in a pulsed manner and chemically adsorbing it onto the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix, and using argon gas to purge excess tetramethylethylamine hafnium from the atomic layer deposition reaction chamber; in step S3, the tetramethylethylamine hafnium... The pulse duration of the amine hafnium is 0.5 s, and the argon purging time is 2 s; S4, ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulse manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite matrix in step S3 to undergo a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas; in step S4, the pulse duration of the ultrapure water is 0.2 s, and the argon purging time is 2 s; S5, steps S3 and S4 are repeated 3000 times; S6, after step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, and the material is taken out from the atomic layer deposition reaction chamber to obtain the hafnium-based ultra-high temperature ceramic matrix composite material; wherein, the thickness of the hafnium oxide coating is 150 nm.

[0092] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 71 MPa in air at 2000℃.

[0093] Comparative Example 6 Comparative Example 6 is basically the same as Example 1, except that: Step (5) is excluded; that is, a hafnium carbide coating with a thickness of 3 μm is prepared on the surface of the hafnium-based ultra-high temperature ceramic matrix composite material matrix by chemical vapor deposition to obtain the hafnium-based ultra-high temperature ceramic matrix composite material.

[0094] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 51 MPa in air at 2000℃.

[0095] Comparative Example 7 (1) Same as step (1) in Example 1.

[0096] (2) Preparation of hafnium-based ultra-high temperature ceramic matrix composite material matrix: Using liquid oxygen-free hafnium carbide ceramic precursor as reactant, the matrix is ​​prepared by reacting with the porous carbon / carbon composite material matrix through impregnation pyrolysis method; wherein, a total of 10 rounds of impregnation, curing and pyrolysis treatment are carried out. Each impregnation is first vacuum impregnated for 1 hour at a pressure of 200 Pa, and then pressure impregnated for 1 hour at a pressure of 2 MPa. The curing temperature is 280℃ and the curing time is 2 hours. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1200℃ and the pyrolysis time is 2 hours. The pyrolysis is carried out in an argon atmosphere.

[0097] (3) Preparation of hafnium carbide coating: A hafnium carbide coating with a thickness of 3 μm was prepared on the surface of a hafnium-based ultra-high temperature ceramic matrix composite substrate by chemical vapor deposition. The chemical vapor deposition was carried out under a pressure of 20 Pa, with hafnium tetrachloride, propane and hydrogen as the reaction source and argon as the carrier gas. The flow ratio of hafnium tetrachloride, propane, hydrogen and argon was 1:6:6:15, and the temperature of chemical vapor deposition was 1200 °C.

[0098] (4) Preparation of hafnium oxide coating: S1, the hafnium-based ultra-high temperature ceramic matrix composite material matrix is ​​placed in an atomic layer deposition reaction chamber, and the temperature of the atomic layer deposition reaction chamber is set to 240℃; S2, tetramethylethylamine hafnium is heated to 80℃; S3, tetramethylethylamine hafnium is introduced into the atomic layer deposition reaction chamber in a pulse manner and chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix, and excess tetramethylethylamine hafnium is purged out of the atomic layer deposition reaction chamber with argon gas; in step S3, the tetramethylethylamine hafnium... The pulse duration of the amine hafnium is 0.5 s, and the argon purging time is 2 s; S4, ultrapure water is introduced into the atomic layer deposition reaction chamber in a pulsed manner and reacts with the tetramethylethylamine hafnium chemically adsorbed on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite material matrix in step S3 to undergo a deposition reaction. Excess ultrapure water and byproducts generated after the deposition reaction are purged out of the atomic layer deposition reaction chamber with argon gas; in step S4, the pulse duration of the ultrapure water is 0.2 s, and the argon purging time is 2 s; S5, steps S3 and S4 are repeated sequentially. 3000 times; S6. After step S5, the temperature of the atomic layer deposition reaction chamber is reduced to below 60°C, the material is taken out from the atomic layer deposition reaction chamber, and the material is placed in an argon atmosphere. The temperature is increased to 700°C at a rate of 35°C / s and held for 50s for ultra-fast annealing. Then, the temperature is reduced to room temperature at a rate of 10°C / s to obtain a hafnium-based ultra-high temperature ceramic matrix composite material; wherein the thickness of the hafnium oxide coating is 150nm.

[0099] Tensile strength test in air at 2000℃: The mechanical properties of the hafnium-based ultra-high temperature ceramic matrix composite material prepared in this comparative example were tested in a high temperature and oxygen environment. The tensile strength was 57 MPa in air at 2000℃.

[0100] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high-performance hafnium-based ultra-high temperature ceramic matrix composite material, characterized in that, The method includes the following steps: (1) A porous carbon / carbon composite matrix is ​​obtained by depositing a pyrolytic carbon interface layer on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition. (2) Using tetramethylethylamine hafnium and water as reactants, a hafnium oxide interface layer was prepared on the surface of the pyrolytic carbon interface layer of the porous carbon / carbon composite matrix by atomic layer deposition and subjected to ultra-fast annealing treatment to obtain a composite matrix containing a pyrolytic carbon-hafnium oxide composite interface layer. (3) Using hafnium carbide ceramic precursor as reactant, react with the composite matrix containing the pyrolytic carbon-hafnium oxide composite interface layer by impregnation pyrolysis method to obtain hafnium-based ultra-high temperature ceramic matrix composite matrix; (4) A hafnium carbide coating was prepared on the surface of the hafnium-based ultra-high temperature ceramic matrix composite material matrix by chemical vapor deposition; (5) Using tetramethylethylamine hafnium and water as reactants, a hafnium oxide coating is prepared on the surface of the hafnium carbide coating of the hafnium-based ultra-high temperature ceramic matrix composite matrix by atomic layer deposition and ultra-fast annealing treatment is performed to obtain a high-performance hafnium-based ultra-high temperature ceramic matrix composite.

2. The preparation method according to claim 1, characterized in that: The density of the carbon fiber preform is 0.15~0.2 g / cm³. 3 Thickness of 1~4mm; and / or The density of the porous carbon / carbon composite matrix is ​​0.2~0.25 g / cm³. 3 .

3. The preparation method according to claim 1, characterized in that: The thickness of the hafnium oxide interface layer is 25~100 nm, preferably 50~100 nm; and / or The thickness of the pyrolytic carbon-hafnium oxide composite interface layer is 0.2~1μm.

4. The preparation method according to claim 1, characterized in that: The thickness of the hafnium carbide coating is 0.5~5μm; and / or The thickness of the hafnium oxide coating is 50~200nm, preferably 150~200nm.

5. The preparation method according to any one of claims 1 to 4, characterized in that, In step (2) and / or step (5): The precursors used in the atomic layer deposition process are tetramethylethylaminohafnium and ultrapure water, and the temperature of the atomic layer deposition reaction is 220~300℃. In step (2), the deposition cycle is 100 to 2000 times; In step (5), the deposition cycle is 200 to 4000 times; The single deposition cycle process is as follows: the pulse time of the tetramethylethylamine hafnium is 0.3~0.6s, and the argon purging time is 1~3s; the pulse time of the ultrapure water is 0.1~0.3s, and the argon purging time is 1~3s.

6. The preparation method according to any one of claims 1 to 4, characterized in that, In step (2) and / or step (5): The ultra-rapid annealing process involves heating to 650-850℃ at a heating rate of 25-50℃ / s and holding at that temperature for 40-100s.

7. The preparation method according to any one of claims 1 to 4, characterized in that, In step (3): The pyrolysis temperature is 1200~1450℃.

8. The preparation method according to any one of claims 1 to 4, characterized in that, In step (4): When preparing hafnium carbide coatings, the chemical vapor deposition temperature is 1100~1400℃, the pressure is 0.1~50Pa, and / or the time is 1~2h.

9. The preparation method according to any one of claims 1 to 4, characterized in that: The high-performance hafnium-based ultra-high temperature ceramic matrix composite material contains a hafnium carbide-hafnium oxide composite coating; and / or The high-performance hafnium-based ultra-high temperature ceramic matrix composite material has a tensile strength greater than 170 MPa at 2000℃ in air atmosphere.

10. A high-performance hafnium-based ultra-high temperature ceramic matrix composite material prepared by the preparation method according to any one of claims 1 to 9.

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