Ceramic matrix composite material with pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer and preparation method thereof

Abstract

The invention relates to a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer and a preparation method of the ceramic matrix composite material. The preparation method comprises the following steps: preparing a pyrolytic carbon layer on the fiber surface of a carbon fiber preform; depositing a Ti2AlB2 layer on the surface of the pyrolytic carbon layer; depositing an HfB2 layer on the surface of the Ti2AlB2 layer to form a three-layer composite interface layer; and compounding the preform with the ceramic-based precursor through an impregnation and cracking technology. Through the design of the three composite interface layers, the advantages of all the materials are fully played, the thermal expansion mismatch stress is effectively relieved, and the high-temperature mechanical property and the oxidation resistance of the composite material are improved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic matrix composite material preparation technology, and particularly relates to a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer and its preparation method. Background Technology

[0002] Carbon fiber reinforced ceramic matrix composites (CFR-CMC) have significant application value in the field of aerospace hot-end components due to their lightweight, high specific strength and excellent high-temperature stability.

[0003] However, during the long-term high-temperature service of high-speed aircraft, the extreme heat flux (>2000°C) and severe thermal shock environment pose serious challenges to the performance of CFR-CMC. The thermal expansion mismatch between carbon fiber and the interface layer, as well as the interface layer and the matrix, and the problem of interface oxidation damage seriously limit its service life.

[0004] Traditional carbon fiber reinforced ceramic matrix composites often employ a single pyrolytic carbon (PyC), boron nitride (BN), or silicon carbide (SiC) interface layer. Among these, the PyC interface layer, due to its layered crystal structure, can effectively deflect cracks and promote fiber debonding, significantly improving the toughness of the composite. However, its fatal flaw is that oxidation occurs above 400°C, leading to interface layer failure and fiber oxidation damage. The BN interface layer not only retains the crack deflection ability of its layered structure, but the B2O3 generated by its oxidation has a self-healing function at high temperatures, effectively sealing cracks and preventing oxygen diffusion, raising the oxidation resistance temperature to 850°C. However, when the temperature exceeds 1000°C, the self-healing ability drops sharply as the liquid B2O3 layer evaporates and is lost, leading to interface protection failure. The SiC interface layer generates dense SiO2 through high-temperature oxidation, raising the high-temperature oxidation resistance temperature to 1600°C, but it is brittle and cannot effectively regulate the fiber / matrix bonding strength.

[0005] Therefore, developing novel interface layer structures that combine thermodynamic compatibility, high fracture toughness, and excellent oxidation resistance has become a key challenge in improving the high-temperature performance of carbon fiber reinforced ceramic matrix composites.

[0006] In existing technologies, researchers have attempted to improve the above problems through multi-interface layer design.

[0007] The literature "Interface modification of carbon fibers with TiC / Ti2AlC coating and its effect on the tensile strength" describes the in-situ growth of TiC / Ti2AlC coatings using the molten salt method. This method easily leads to microcracks and micropores on the carbon fiber surface, significantly reducing the fiber's tensile strength. The resulting strong interfacial bonding causes stress concentration, and cracks easily penetrate the fiber, resulting in brittle fracture.

[0008] CN202110351928.4 proposes to synthesize the Ti3SiC2 interface phase in situ on the surface of SiC fibers using chemical vapor deposition (CVD) combined with molten salt method, and to achieve crack deflection by utilizing its MAX phase layered structure. However, the diffusion depth of Ti ions is limited by the molten salt medium, and the release of active silicon at high temperature can easily lead to the generation of by-products.

[0009] The PyC / BN / SiC three-layer composite self-healing interface layer design proposed in CN202011305519.2 addresses the issue that the thermal expansion coefficients of PyC, BN, and SiC differ significantly (PyC, BN, and SiC have thermal expansion coefficients of 2×10⁻⁶, respectively). −6 / K, 2.7×10 −6 / K and 4.8×10 −6 / K), on the other hand, the viscosity of the glass phase formed by high-temperature oxidation of BN decreases sharply at ultra-high temperatures (>1500°C), causing the self-healing effect to fail, resulting in a relatively low lifespan of the design under high-temperature service conditions.

[0010] CN202310798894.2 employs a composite interface layer with alternating PyC / SiC deposition to hinder the oxidation of the carbon fiber and PyC interface. However, the SiO2 glass layer formed by SiC at ultra-high temperatures (>1600°C) will have reduced erosion resistance due to its low viscosity.

[0011] CN201910737155.6 proposes preparing a ZrB2 interface layer on the surface of carbon fibers to improve their high-temperature oxidation resistance. However, the thermal expansion coefficients of carbon fibers and ZrB2 differ significantly (the radial thermal expansion coefficient of carbon fibers is approximately 1-2 × 10⁻⁶). −6 The coefficient of thermal expansion of ZrB2 is approximately 5.9 × 10⁻⁶ K. −6 / K), which causes the ZrB2 interface layer to fail prematurely under large thermal mismatch stress.

[0012] While these methods can partially improve interface performance, they all still suffer from the core contradiction between matching the thermal expansion coefficient gradient and synergistic enhancement of antioxidant properties.

[0013] In summary, the interface layer design of existing carbon fiber reinforced ceramic matrix composites still has the following bottlenecks: 1) The thermal expansion coefficient design between single or double interface layer materials is unreasonable, which cannot effectively alleviate thermal mismatch stress; 2) The high-temperature oxidation resistance and ablation resistance of the interface layer are insufficient, making it difficult to adapt to extreme service environments; 3) The interface layer itself has low toughness and is prone to becoming a crack propagation channel.

[0014] Therefore, there is an urgent need to develop a composite interface layer structure that combines a transitional coefficient of thermal expansion, high fracture toughness, and ultra-high temperature stability in order to achieve long-term reliable service of carbon fiber reinforced ceramic matrix composites in extreme thermal protection scenarios. Summary of the Invention

[0015] To address the problems of mismatched thermal expansion coefficients and insufficient high-temperature oxidation resistance in the interface layer of carbon fiber reinforced ceramic matrix composites in existing technologies, this invention provides a carbon fiber reinforced ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 interface layer and its preparation method.

[0016] Specifically, in a first aspect, the present invention provides a method for preparing a carbon fiber reinforced ceramic matrix composite material having a pyrolytic carbon-Ti2AlB2-HfB2 composite interface layer, the method comprising the following steps: (1) A pyrolytic carbon layer is deposited on the fiber surface of the carbon fiber preform to obtain a first preform with a pyrolytic carbon layer deposited on it; (2) A Ti2AlB2 layer is deposited on the surface of the pyrolytic carbon layer to obtain a second preform with a pyrolytic carbon-Ti2AlB2 bilayer deposited on it; (3) A HfB2 layer is deposited on the surface of the Ti2AlB2 layer to obtain a third preform with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer deposited; (4) A ceramic matrix is ​​prepared by impregnation and pyrolysis of the third preform using a ceramic matrix precursor to obtain a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer.

[0017] In a second aspect, the present invention provides a ceramic matrix composite material having a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer, prepared by the preparation method described in the first aspect of the present invention.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Through the innovative design of a three-layer composite interface structure of “pyrolytic carbon (PyC)-Ti2AlB2-HfB2”, a continuous gradient of thermal expansion coefficients from fiber to matrix is ​​formed, achieving precise matching of gradient thermal expansion coefficients. This gradient transition can effectively alleviate the interfacial thermal stress caused by the difference in thermal expansion coefficients of each component, fundamentally solving the problem of microcracks and premature failure caused by excessive thermal mismatch stress in single or double-layer interface layers.

[0019] (2) The layered structure of the PyC layer and the Ti2AlB2 interlayer (MAB phase) can effectively deflect cracks and endow the composite material with excellent fracture toughness; at the same time, the high hardness and high strength of the Ti2AlB2 and HfB2 layers themselves significantly enhance the load-bearing capacity of the interface layer. This synergistic effect enables the composite material to maintain high flexural strength and high fracture toughness at a high temperature of 1600°C, achieving a good balance between toughness and strength.

[0020] (3) The outermost HfB2 layer generates a dense, stable HfO2 protective layer with a low volatilization rate during ultra-high temperature oxidation, raising the effective oxidation resistance temperature to above 1600°C. At the same time, the Al2O3-B2O3 composite glass phase generated by the oxidation of the Ti2AlB2 layer, in synergy with the HfO2 layer, provides superior self-healing ability and erosion resistance compared to traditional BN (B2O3) or SiC (SiO2) interface layers, making it particularly suitable for extreme service environments above 2000°C.

[0021] (4) Chemical vapor deposition (CVD) is used for three-step continuous deposition, avoiding the drawbacks of molten salt methods that may damage fibers and introduce impurities. This process can achieve precise control of the thickness and composition of each layer, forming a uniform, dense, and highly bonded gradient interface structure, providing a reliable process guarantee for the above-mentioned performance advantages.

[0022] (5) The innovative use of Ti2AlB2 (MAB phase) as the intermediate layer has higher hardness and flexural strength, as well as better oxidation resistance compared to the traditional MAX phase (such as Ti2AlC). Its coefficient of thermal expansion is between PyC and HfB2, making it an ideal transition layer for achieving gradient matching. This is a characteristic advantage that conventional materials do not possess. Detailed Implementation

[0023] 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.

[0024] The present invention provides, in a first aspect, a method for preparing a ceramic matrix composite material having a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer, the method comprising the following steps: (1) A pyrolytic carbon layer is deposited on the fiber surface of the carbon fiber preform to obtain a first preform with a pyrolytic carbon layer deposited on it; (2) A Ti2AlB2 layer is deposited on the surface of the pyrolytic carbon layer to obtain a second preform with a pyrolytic carbon-Ti2AlB2 bilayer deposited on it; (3) A HfB2 layer is deposited on the surface of the Ti2AlB2 layer to obtain a third preform with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer deposited; (4) A ceramic matrix is ​​prepared by impregnation and pyrolysis of the third preform using a ceramic matrix precursor to obtain a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer.

[0025] This invention fully leverages the advantages of each material by depositing a gradient pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite material as an interface layer on the fiber surface. Specifically, this invention first deposits a pyrolytic carbon layer as a buffer layer on the carbon fiber surface, followed by the sequential deposition of a Ti2AlB2 layer and an HfB2 layer, forming a composite interface layer with a gradient coefficient of thermal expansion. The pyrolytic carbon layer has a similar coefficient of thermal expansion to the carbon fiber, resulting in good bonding and effectively mitigating the difference in thermal expansion between the carbon fiber and the Ti2AlB2 layer. The Ti2AlB2 layer also acts as an intermediate transition layer (the coefficient of thermal expansion of Ti2AlB2 is approximately 3.5 × 10⁻⁶). −6 / K), further reducing the difference in thermal expansion coefficient with the HfB2 layer (HfB2's thermal expansion coefficient is approximately 6.3 × 10⁻⁶ K). −6The HfB2 layer (478 MPa) provides a higher flexural strength than known MAX phase materials, significantly reducing the thermal mismatch stress at the interface, improving the bonding strength between the HfB2 layer and the carbon fiber, and enhancing the interfacial stability of the composite material under high-temperature cycling and thermal shock conditions. Above 1600°C, the HfB2 layer forms a dense HfO2 layer, further improving the high-temperature oxidation and ablation resistance of the composite material. Existing technologies have proposed preparing a ZrB2 interface layer on the carbon fiber surface to improve the high-temperature oxidation resistance of the carbon fiber. However, due to the large difference in thermal expansion coefficients between the carbon fiber and ZrB2, the ZrB2 interface layer is prone to microcracks under large thermal mismatch stress. At high temperatures, oxygen diffuses along the cracks to the carbon fiber, causing premature oxidation and failure of the carbon fiber. In comparison, this invention overcomes the problem of mismatch in thermal expansion coefficients between the existing HfB2 interface layer and carbon fiber. At the same time, the melting point of HfB2 (3380°C) is higher than that of ZrB2 (3250°C), and the HfO2 layer formed after high-temperature oxidation of HfB2 in ultra-high temperature environments (such as above 2000°C) has a lower volatilization rate and higher stability than the HfO2 layer, thus maintaining its antioxidant protection capability at higher temperatures.

[0026] The three-layer composite interface layer of this invention significantly improves the high-temperature oxidation resistance of the composite material under high-temperature oxidizing conditions and extends its service life by optimizing the selection of materials and structural design of each layer. This invention utilizes the intermediate transition thermal expansion coefficient of the Ti2AlB2 layer to alleviate thermal mismatch stress, while the Al2O3-B2O3 composite glass phase generated at high temperatures exhibits better density and self-healing ability compared to traditional BN oxides, effectively preventing oxygen diffusion into the fiber interior. Compared to the existing PyC / BN / SiC three-layer composite self-healing interface layer design and the composite interface layer design using alternating PyC / SiC deposition, the three-layer composite interface layer of this invention avoids the problem of insufficient erosion resistance caused by the excessively low viscosity of B2O3 and SiO2 glass layers at high temperatures. It synergistically improves the fracture toughness and high-temperature stability of the composite material, avoiding interface damage and self-healing failure caused by excessive differences in thermal expansion coefficients, and significantly improving the service life of the composite material under high-temperature service conditions.

[0027] The following section will provide further explanation in a step-by-step manner.

[0028] Step (1): Preparation of pyrolytic carbon layer In this step, the preform can be placed in a chemical vapor deposition furnace to prepare a pyrolytic carbon layer (PyC layer) on the fiber surface. Subsequently, Ar gas can be introduced into the high-temperature furnace to remove the remaining reactive gases, thus obtaining the first preform.

[0029] The carbon fiber preform used in this step is preferably a carbon fiber braided structure with a carbon fiber braided skeleton. The braiding method can be any of needle punching, sewing, or piercing. This invention does not specifically limit the source of the carbon fiber preform; it can be a commercially available product or prepared using existing methods.

[0030] Preferably, the density of the carbon fiber preform is 0.4~0.6 g / cm³. 3 For example, 0.4, 0.45, 0.5, 0.55, or 0.6 g / cm³. 3 .

[0031] Preferably, the carbon fiber preform can undergo heat treatment in a vacuum environment (e.g., heat treatment of the carbon fiber in a vacuum furnace) before the deposition of the pyrolytic carbon layer to remove surface impurities and ensure a more uniform subsequent deposition process.

[0032] Preferably, the heat treatment temperature is 400~500°C (e.g. 400, 420, 440, 460, 480 or 500°C), and the holding time is 30~40 min (e.g. 20, 25, 30, 35 or 40 min).

[0033] After heat treatment, the preform can be placed in a chemical vapor deposition furnace for chemical vapor deposition to prepare a pyrolytic carbon layer.

[0034] Preferably, the deposition uses methane, hydrogen, and argon as raw materials, and an inert gas is introduced after deposition to purge the reactant gases. Specifically, the deposition can be carried out using CH4 as the raw material gas, H2 as the reducing gas, and argon (Ar) as the carrier gas. Preferably, the CH4 flow rate is 50-150 sccm (e.g., 50, 80, 100, 120, or 150 sccm), the H2 flow rate is 200-300 sccm (e.g., 200, 220, 240, 260, 280, or 300 sccm), and the Ar flow rate is 300-800 sccm (e.g., 300, 400, 500, 600, 700, or 800 sccm).

[0035] Preferably, the deposition temperature is 1000-1200°C (e.g., 1000, 1050, 1100, 1150 or 1200°C) and the pressure is 10. -1 -10 -3 mbar (e.g., 10) -1 mbar, 10 -2 mbar or 10 -3 mbar), deposition time of 5-15 h (e.g. 5, 7, 9, 11, 13 or 15 h).

[0036] Preferably, the thickness of the pyrolytic carbon substrate is 0.2-0.5 μm (e.g., 0.2, 0.3, 0.4 or 0.5 μm).

[0037] Preferably, argon or nitrogen is introduced to remove the remaining reaction gases at a flow rate of 1000-1500 sccm (e.g., 1000, 1100, 1200, 1300, 1400 or 1500 sccm) for 15-30 min (e.g., 15, 18, 21, 24, 27 or 30 min).

[0038] Step (2): Preparation of Ti2AlB2 layer After completing step (1), the feed gas can be switched, and a Ti2AlB2 layer can be deposited on the surface of the PyC layer of the first preform in a chemical vapor deposition furnace. Subsequently, an inert gas, such as Ar, can be introduced into the high-temperature furnace to remove any remaining reactive gases.

[0039] Preferably, the Ti2AlB2 layer is deposited on the surface of the pyrolytic carbon layer using titanium tetrachloride, trimethylaluminum or aluminum chloride, diborane, hydrogen and argon as raw materials, and an inert gas is introduced after the deposition is completed to remove the reaction gases.

[0040] For example, after completing step (1), the raw material gas can be switched to TiCl4, AlCl3 (or Al(CH3)3) and B2H6, with H2 as the reducing gas and argon (Ar) as the carrier gas for chemical vapor deposition.

[0041] Preferably, the TiCl4 flow rate is 30-80 sccm (e.g., 30 sccm, 40 sccm, 50 sccm, 60 sccm or 80 sccm); the AlCl3 (or Al(CH3)3) flow rate is 20-60 sccm (e.g., 20 sccm, 30 sccm, 40 sccm, 50 sccm or 60 sccm); the B2H6 flow rate is 10-40 sccm (e.g., 10 sccm, 20 sccm, 30 sccm or 40 sccm); the H2 flow rate is 150-350 sccm (e.g., 150 sccm, 200 sccm, 250 sccm, 300 sccm or 350 sccm); and the Ar flow rate is 300-800 sccm (e.g., 300, 400, 500, 600, 700 or 800 sccm).

[0042] Preferably, the deposition temperature is 1400-1700°C (e.g., 1400°C, 1500°C, 1600°C, or 1700°C); the pressure is 10... -1 -10 -3 mbar (e.g., 10) -1 mbar, 10 -2MBA or 10 -3 mbar); deposition time is 6-20 h (e.g., 6, 8, 10, 12, 14, 16, 18 or 20 h).

[0043] Preferably, the thickness of the formed Ti2AlB2 intermediate layer is 0.2-0.5 μm (e.g., 0.2, 0.3, 0.4 or 0.5 μm).

[0044] Preferably, argon or nitrogen is introduced to remove the remaining reaction gases at a flow rate of 1000-1500 sccm (e.g., 1000, 1100, 1200, 1300, 1400 or 1500 sccm) for 15-30 min (e.g., 15, 18, 21, 24, 27 or 30 min).

[0045] Step (3): Preparation of HfB2 layer After completing step (2), the raw material gas can be switched, and an HfB2 layer can be deposited on the surface of the Ti2AlB2 layer of the second preform in a chemical vapor deposition furnace, thereby forming a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer on the carbon fiber surface.

[0046] Preferably, the deposition uses hafnium tetrachloride, diborane, hydrogen and argon as raw materials to deposit an HfB2 layer on the surface of the Ti2AlB2 layer, thereby forming a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer on the surface of the carbon fiber.

[0047] Preferably, the HfCl4 flow rate is 40-100 sccm (e.g., 40, 60, 80 or 100 sccm), the B2H6 flow rate is 15-50 sccm (e.g., 15, 25, 35 or 50), the H2 flow rate is 200-300 sccm (e.g., 200, 220, 240, 260, 280 or 300 sccm), and the Ar flow rate is 300-800 sccm (e.g., 300, 400, 500, 600, 700 or 800 sccm).

[0048] Preferably, the deposition temperature is 1500-1800°C (e.g., 1500, 1600, 1700 or 1800°C) and the pressure is 10. -1 -10 -3 mbar (e.g., 10) -1 mbar, 10 -2 mbar or 10 -3 mbar), deposition time is 6-20h (e.g. 6, 8, 10, 12, 14, 16, 18 or 20h).

[0049] Preferably, the thickness of the formed HfB2 top layer is 0.2-0.5 μm (e.g., 0.2, 0.3, 0.4 or 0.5 μm).

[0050] Step (4): Preparation of ceramic matrix In this step, a porous carbon fiber preform (the third preform) with a pyrolytic carbon / Ti2AlB2 / HfB2 three-layer composite interface layer is prepared by impregnation pyrolysis technology (i.e., the third preform is impregnated in the ceramic precursor and then pyrolyzed) to prepare a ceramic matrix and then composite it with the ceramic matrix precursor to achieve densification of the preform and obtain a ceramic matrix composite material.

[0051] In some preferred embodiments, the ceramic-based precursor includes, but is not limited to, siloxanes, polycarbosilanes, or boron carbides, for example, one or more of these may be used.

[0052] Preferably, vacuum or pressure impregnation is performed, with a vacuum degree of 10 for vacuum impregnation. 2 Pa-10 4 Pa (e.g., 10) 2 10 3 , or 10 4 Pa), the pressure impregnation pressure is 1×10 6- 5× 106 (e.g., 1×10) 6 2.5×10 6 or 5×10 6 The soaking time is 1-3 hours (e.g., 1, 1.5, 2, 2.5 or 3 hours).

[0053] Preferably, the curing temperature is 100-300°C (e.g., 100, 200 or 300°C) and the curing time is 1-3 hours (e.g., 1, 1.5, 2, 2.5 or 3 hours).

[0054] Preferably, the pyrolysis temperature is 1200-1700°C (e.g., 1200, 1300, 1400, 1500, 1600 or 1700°C), and the pyrolysis time is 2-4h (2, 2.5, 3, 3.5 or 4h).

[0055] Through impregnation and pyrolysis, the precursor is transformed into a ceramic matrix.

[0056] Preferably, the above impregnation, curing, and pyrolysis process can be repeated multiple times until a density of 2.0~3.0 g / cm³ is obtained. 3 (e.g., 2, 2.2, 2.4, 2.6, 2.8 or 3.0 g / cm³) 3 Carbon fiber reinforced ceramic matrix composites.

[0057] In some more preferred embodiments, the preparation method of the present invention may include the following steps: (1) For a density of 0.4~0.6 / cm 3 Porous carbon fiber preforms are pretreated by holding at 400-500°C in a vacuum environment for 30-40 minutes to remove surface impurities such as colloids, ensuring the uniformity of the interface layer in subsequent deposition processes. Then, the pretreated porous carbon fiber preforms are placed in a chemical vapor deposition furnace, using methane (CH4) as the carbon source, hydrogen (H2) as the reducing gas, and argon (Ar) as the carrier gas, to prepare a pyrolytic carbon layer on the fiber surface. The CH4 flow rate is 50-150 sccm, the H2 flow rate is 200-300 sccm, the Ar flow rate is 300-800 sccm, the deposition temperature is 1000-1200°C, and the pressure is 10... -1 -10 -3 The deposition time is 5-15 h, forming a pyrolytic carbon substrate with a thickness of 0.2-0.5 μm. Argon or nitrogen gas is then introduced at a flow rate of 1000-1500 sccm to remove residual reaction gases for 15-30 min. (2) Switching the raw material gases: In a chemical vapor deposition furnace, using titanium tetrachloride (TiCl4), trimethylaluminum (Al(CH3)3) or aluminum chloride (AlCl3) and diborane (B2H6) as raw materials, hydrogen (H2) as the reducing gas, and argon (Ar) as the carrier gas, a Ti2AlB2 layer is deposited on the surface of the PyC layer using a three-source co-deposition method. The TiCl4 flow rate is 30-80 sccm, the Al(CH3)3 or AlCl3 flow rate is 20-60 sccm, the B2H6 flow rate is 10-40 sccm, the H2 flow rate is 150-350 sccm, the Ar flow rate is 300-800 sccm, the deposition temperature is 1400-1700°C, and the pressure is 10 -1 -10 -3 The deposition time is 6-20 h, forming a Ti2AlB2 intermediate layer with a thickness of 0.2-0.5 μm. Then, argon or nitrogen gas is introduced at a flow rate of 1000-1500 sccm for 15-30 min to remove residual gases. (3) Switch the feed gas and continue depositing an HfB2 layer on the surface of the Ti2AlB2 layer in a chemical vapor deposition furnace using hafnium tetrachloride (HfCl4) and diborane (B2H6) as feedstocks, hydrogen (H2) as reducing gas, and argon (Ar) as carrier gas. The flow rate of HfCl4 is 40-100 sccm, the flow rate of B2H6 is 15-50 sccm, the flow rate of H2 is 200-300 sccm, the flow rate of Ar is 300-800 sccm, the deposition temperature is 1500-1800°C, and the pressure is 10. -1 -10 -3A pyrolytic carbon / Ti2AlB2 / HfB2 three-layer composite interface layer was prepared on the carbon fiber surface at a deposition time of 6-20 h, forming a top layer of HfB2 with a thickness of 0.2-0.5 μm. (4) A porous carbon fiber preform with a pyrolytic carbon / Ti2AlB2 / HfB2 three-layer composite interface layer was prepared by impregnation pyrolysis technology to prepare a ceramic matrix and then composite it with the ceramic matrix precursor.

[0058] In this invention, it is preferred that the deposition described in steps (1) to (3) be carried out by a three-source co-deposition method, that is, after completing step (1), the deposition in step (2) is carried out by switching the raw material gas, and after completing step (2), the deposition in step (3) is carried out by switching the raw material gas.

[0059] Existing technologies have proposed using chemical vapor deposition (CVD) combined with molten salt methods to synthesize the Ti3SiC2 interface phase in situ on the surface of SiC fibers. However, the diffusion depth of Ti ions is limited by the molten salt medium, and the release of active silicon at high temperatures easily leads to the formation of byproducts. The preparation method of this invention can select to use a three-source co-deposition method to sequentially deposit a pyrolytic carbon layer, a Ti2AlB2 layer, and an HfB2 layer on the carbon fiber surface. This allows for precise control of the thickness and composition of each layer, forming a uniform pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer, effectively avoiding the formation of byproducts. At the same time, the gradient structure allows for a gradual transition in the coefficient of thermal expansion, significantly reducing the thermal mismatch stress at the interface.

[0060] In a second aspect, the present invention provides a ceramic matrix composite material having a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer, prepared by the preparation method described in the first aspect of the present invention.

[0061] In the pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer of the ceramic matrix composite material of the present invention, the pyrolytic carbon layer is adjacent to the carbon fiber surface, the Ti2AlB2 layer is located above the pyrolytic carbon layer, and the HfB2 layer is the outermost layer covering the surface of the Ti2AlB2 layer. The three layers form a gradient of thermal expansion coefficients with similar expansion coefficients, resulting in low thermal mismatch stress, high bonding strength, good high-temperature oxidation and ablation resistance, and excellent interfacial stability under high-temperature cycling and thermal shock conditions. The composite material of the present invention exhibits a flexural strength of 314 MPa or higher, preferably 340 MPa or higher, and even up to 389 MPa in a high-temperature air environment at 1600°C; the fracture toughness is 6.8 MPa·m. 1 / 2 The preferred value is 7.2 MPaˑm. 1 / 2 The above, and even up to 8.6 MPaˑm 1 / 2 It is expected to be applicable to extreme environments above 2000°C.

[0062] 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.

[0063] Example 1 This embodiment prepares a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface. The preparation method includes the following steps: ① Processing porous carbon fiber preforms: Take a density of 0.5 g / cm³ 3 The carbon fiber needle-punched woven preform was heated at 450°C for 30 minutes in a vacuum environment to remove impurities, and the fiber preform was obtained for use.

[0064] ② Preparation of pyrolytic carbon layer: In a chemical vapor deposition furnace, with CH4 flow rate of 100 sccm, H2 flow rate of 250 sccm, Ar flow rate of 500 sccm, deposition temperature of 1100°C, and pressure of 10... -2 A pyrolytic carbon substrate with a thickness of 0.35 μm was formed by deposition at mbar for 10 h, yielding the first preform. Ar was introduced at a flow rate of 1200 sccm to purge the reaction gases for 20 min.

[0065] ③ Deposition of Ti2AlB2 layer: Switch feed gas to TiCl4 flow rate 50 sccm, AlCl3 flow rate 40 sccm, B2H6 flow rate 25 sccm, H2 flow rate 250 sccm, Ar flow rate 500 sccm, deposition temperature 1500°C, pressure 10 -2 A Ti₂AlB₂ intermediate layer with a thickness of 0.35 μm was formed at mbar and deposition time of 12 h, yielding the second preform. Ar was introduced at a flow rate of 1200 sccm to purge the reactant gases for 20 min.

[0066] ④ Deposition of HfB2 layer: Continue switching feed gas, with HfCl4 flow rate of 70 sccm, B2H6 flow rate of 30 sccm, H2 flow rate of 250 sccm, and Ar flow rate of 500 sccm, deposition temperature of 1600°C, and pressure of 10. -2 A top layer of HfB2 with a thickness of 0.35 μm was formed by mbar deposition time of 12 h, resulting in the third preform.

[0067] ⑤ Preparation of ceramic matrix composites: A preform with a three-layer composite interface layer deposited is immersed in a polycarbosilane ceramic precursor at an impregnation pressure of 10. 2 Pa, impregnation time 2h, followed by pyrolysis treatment at 1400°C for 3h, the impregnation and pyrolysis process was repeated 10 times.

[0068] The sample prepared in this embodiment has a density of 2.32 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 352 MPa. The fracture toughness was measured to be 7.8 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0069] Example 2 This embodiment prepares a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface. The preparation method includes the following steps: ①The steps are the same as in Example 1.

[0070] ② Preparation of pyrolytic carbon layer: In a chemical vapor deposition furnace, with CH4 flow rate of 100 sccm, H2 flow rate of 250 sccm, Ar flow rate of 500 sccm, deposition temperature of 1100°C, and pressure of 10... -2 A pyrolytic carbon substrate with a thickness of 0.45 μm was formed at mbar and a deposition time of 12 h, yielding the first preform. Ar was introduced at a flow rate of 1000 sccm to purge the reaction gases for 15 min.

[0071] ③ is the same as step ③ in Example 1.

[0072] ④ Deposition of HfB2 layer: Continue switching feed gas, with HfCl4 flow rate of 70 sccm, B2H6 flow rate of 30 sccm, H2 flow rate of 250 sccm, and Ar flow rate of 500 sccm, deposition temperature of 1600°C, and pressure of 10. -2 A top layer of HfB2 with a thickness of 0.25 μm was formed by mbar deposition time of 8 h, resulting in the third preform.

[0073] ⑤ is the same as step ⑤ in Example 1.

[0074] The sample prepared in this embodiment has a density of 2.31 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 377 MPa. The fracture toughness was measured to be 8.0 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0075] Example 3 This embodiment prepares a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface. The preparation method includes the following steps: ①The steps are the same as in Example 1.

[0076] ② Preparation of pyrolytic carbon layer: In a chemical vapor deposition furnace, with CH4 flow rate of 100 sccm, H2 flow rate of 250 sccm, Ar gas flow rate of 500 sccm, deposition temperature of 1100°C, and pressure of 10... -2 A pyrolytic carbon substrate with a thickness of 0.25 μm was formed by deposition at mbar for 5 h, yielding the first preform. Ar was introduced at a flow rate of 1000 sccm to purge the reaction gases for 15 min.

[0077] ③ is the same as step ③ in Example 1.

[0078] ④ Deposition of HfB2 layer: Continue switching feed gas, with HfCl4 flow rate of 70 sccm, B2H6 flow rate of 30 sccm, H2 flow rate of 250 sccm, and Ar flow rate of 500 sccm, deposition temperature of 1600°C, and pressure of 10. -2 A top layer of HfB2 with a thickness of 0.45 μm was formed by mbar deposition time of 16 h, resulting in the third preform.

[0079] ⑤ is the same as step ⑤ in Example 1.

[0080] The sample prepared in this embodiment has a density of 2.38 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 340 MPa. The fracture toughness was measured to be 7.5 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0081] Example 4 This embodiment prepares a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface. The preparation method includes the following steps: ①The steps are the same as in Example 1.

[0082] ② Preparation of pyrolytic carbon layer: In a chemical vapor deposition furnace, with CH4 flow rate of 120 sccm, H2 flow rate of 300 sccm, Ar flow rate of 600 sccm, deposition temperature of 1200°C, and pressure of 10... -2A pyrolytic carbon substrate with a thickness of 0.45 μm was formed by deposition at mbar for 10 h, yielding the first preform. Ar was introduced at a flow rate of 1000 sccm to purge the reaction gases for 15 min.

[0083] ③ Deposition of Ti2AlB2 layer: Switch feed gas to TiCl4 flow rate 70 sccm, AlCl3 flow rate 50 sccm, B2H6 flow rate 35 sccm, H2 flow rate 300 sccm, Ar flow rate 600 sccm, deposition temperature 1600°C, pressure 10 -2 A Ti₂AlB₂ intermediate layer with a thickness of 0.45 μm was formed at mbar and deposition time of 12 h, yielding the second preform. Ar was introduced at a flow rate of 1200 sccm to purge the reactant gases for 20 min.

[0084] ④ Deposition of HfB2 layer: Continue switching feed gas, with HfCl4 flow rate of 85 sccm, B2H6 flow rate of 40 sccm, H2 flow rate of 300 sccm, and Ar flow rate of 600 sccm, deposition temperature of 1700°C, and pressure of 10 -2 A top layer of HfB2 with a thickness of 0.45 μm was formed by mbar deposition time of 12 h, resulting in the third preform.

[0085] ⑤ is the same as step ⑤ in Example 1.

[0086] The sample prepared in this embodiment has a density of 2.46 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 379 MPa. The fracture toughness was measured to be 8.4 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0087] Example 5 This embodiment is basically the same as Embodiment 1, except that in step ③, the Ti2AlB2 layer is deposited: the raw material gas is changed from AlCl3 to Al(CH3)3, the flow rate of Al(CH3)3 is 50 sccm, and the other parameters remain unchanged, forming a Ti2AlB2 intermediate layer with a thickness of 0.35 μm.

[0088] The sample prepared in this embodiment has a density of 2.33 g / cm³. 3A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 359 MPa. The fracture toughness was measured to be 7.9 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0089] Example 6 This embodiment is basically the same as Embodiment 1, except that step ① processes the porous carbon fiber preform: a density of 0.65 g / cm³ is used. 3 The carbon fiber stitched woven preform was heat-treated at 450°C for 35 minutes in a vacuum environment to remove impurities.

[0090] The sample prepared in this embodiment has a density of 2.49 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 389 MPa. The fracture toughness was measured to be 8.6 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0091] Example 7 This embodiment is basically the same as Embodiment 1, except that step ① processes the porous carbon fiber preform: a density of 0.6 g / cm³ is used. 3 The carbon fiber pierced braided preform was heat-treated at 450°C for 35 minutes in a vacuum environment to remove impurities.

[0092] The sample prepared in this embodiment has a density of 2.43 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 382 MPa. The fracture toughness was measured to be 8.4 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0093] Example 8 This embodiment is basically the same as Embodiment 1, except that step ⑤, preparing the ceramic matrix composite material, involves immersing a preform with a three-layer composite interface layer deposited in a polyzirconium oxane ceramic precursor at an impregnation pressure of 10. 2Pa, impregnation time 2h, followed by pyrolysis treatment at 1700°C for 3h, the impregnation and pyrolysis process was repeated 10 times.

[0094] The sample prepared in this embodiment has a density of 2.66 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 351 MPa. The fracture toughness was measured to be 7.2 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0095] Example 9 The difference between this embodiment and Embodiment 1 is that the carbon fiber preform is not subjected to high-temperature treatment in step ①.

[0096] The sample prepared in this comparative example had a density of 2.30 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 314 MPa. The fracture toughness was measured to be 6.8 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0097] Comparative Example 1 The difference between this comparative example and Example 1 is that: in step ③, a Ti2AlB2 layer is not deposited, and an HfB2 layer is directly deposited on the surface of the pyrolytic carbon layer.

[0098] A density of 2.30 g / cm³ was obtained through empirical comparison. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2 layer composite interface was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 267 MPa. The fracture toughness was measured to be 5.2 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0099] Comparative Example 2 The difference between this comparative example and Example 1 is that: in step ④, no HfB2 layer is deposited, and Ti2AlB2 is deposited only on the surface of the pyrolytic carbon layer. The sample prepared in this comparative example had a density of 2.28 g / cm³. 3A ceramic matrix composite material with a pyrolytic carbon-HfB2 composite interface layer was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 281 MPa. The fracture toughness was measured to be 6.1 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0100] Comparative Example 3 The difference between this comparative example and Example 1 is that: in step ②, a pyrolytic carbon layer is not deposited, and a Ti2AlB2 layer is directly deposited on the surface of the carbon fiber. The sample prepared in this comparative example had a density of 2.30 g / cm³. 3 The ceramic matrix composite material with a Ti2AlB2-HfB2 composite interface layer was subjected to high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 229 MPa. The fracture toughness was measured to be 4.8 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0101] Comparative Example 4 The difference between this comparative example and Example 1 lies in step ②, the preparation of the pyrolytic carbon layer: in a chemical vapor deposition furnace, with a CH4 flow rate of 100 sccm, an H2 flow rate of 250 sccm, an Ar flow rate of 500 sccm, a deposition temperature of 1100°C, and a pressure of 10... -2 A pyrolytic carbon substrate with a thickness of 0.05 μm was formed by deposition at mbar for 1.5 h. Ar was introduced at a flow rate of 1200 sccm to purge the reaction gases for 20 min.

[0102] The sample prepared in this comparative example had a density of 2.31 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to a high-temperature bending test according to GJB10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 297 MPa. The fracture toughness was measured to be 6.3 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0103] Comparative Example 5 The difference between this comparative example and Example 1 lies in step ②, the preparation of the pyrolytic carbon layer: in a chemical vapor deposition furnace, with a CH4 flow rate of 100 sccm, an H2 flow rate of 250 sccm, an Ar flow rate of 500 sccm, a deposition temperature of 1100°C, and a pressure of 10... -2A pyrolytic carbon substrate with a thickness of 1.2 μm was formed by deposition at mbar for 30 h. Ar was introduced at a flow rate of 1200 sccm to purge the reaction gases for 20 min.

[0104] The sample prepared in this comparative example had a density of 2.34 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 288 MPa. The fracture toughness was measured to be 6.2 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0105] Comparative Example 6 The difference between this comparative example and Example 1 lies in the deposition of the Ti2AlB2 layer in step ③: the feed gas was switched to a flow rate of 50 sccm for TiCl4, 40 sccm for AlCl3, 25 sccm for B2H6, 250 sccm for H2, and 500 sccm for Ar, with a deposition temperature of 1500°C and a pressure of 10. -2 A Ti₂AlB₂ intermediate layer with a thickness of 1.2 μm was formed by deposition at mbar for 35 h. Ar was introduced at a flow rate of 1200 sccm to purge the reactant gases for 20 min.

[0106] The sample prepared in this comparative example had a density of 2.36 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 302 MPa. The fracture toughness was measured to be 6.3 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0107] Comparative Example 7 The difference between this comparative example and Example 1 lies in the HfB2 layer deposition in step ④: the feed gas is continuously switched with an HfCl4 flow rate of 70 sccm, a B2H6 flow rate of 30 sccm, an H2 flow rate of 250 sccm, and an Ar flow rate of 500 sccm, while the deposition temperature is 1600°C and the pressure is 10. -2 A top layer of HfB2 with a thickness of 1.2 μm was formed by mbar deposition time of 35 h.

[0108] The sample prepared in this comparative example had a density of 2.39 g / cm³. 3A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 272 MPa. The fracture toughness was measured to be 5.8 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0109] Comparative Example 8 The difference between this comparative example and Example 1 lies in the composite of the ceramic matrix in step ⑤: the third preform with the three-layer composite interface layer deposited is immersed in the polycarbosilane ceramic precursor for 2 hours, followed by pyrolysis treatment at 1400°C for 3 hours, and the immersion and pyrolysis process is repeated 4 times.

[0110] The sample prepared in this comparative example had a density of 1.83 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to high-temperature bending testing according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 216 MPa. The fracture toughness was measured to be 4.5 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0111] Comparative Example 9 The difference between this comparative example and Example 1 is that no pyrolytic carbon layer and Ti2AlB2 layer are deposited. Instead, a ZrB2 layer is deposited only on the surface of the carbon fiber using a CVD method with ZrCl4, B2H6, and H2 as raw materials. The ZrCl4 flow rate is 70 sccm, the B2H6 flow rate is 30 sccm, the H2 flow rate is 250 sccm, and the Ar flow rate is 500 sccm. The deposition temperature is 1600°C and the pressure is 10. -2 mbar, deposition time 25h, to form a ZrB2 interface layer with a thickness of 1μm as obtained in patent CN201910737155.6.

[0112] The sample prepared in this comparative example had a density of 2.24 g / cm³. 3 A ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 257 MPa. The fracture toughness was measured to be 5.2 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0113] Comparative Example 10 This comparative example is based on the method described in patent CN202110351928.4.

[0114] First, at a density of 0.5 g / cm³ 3 A 0.5 μm pyrolytic carbon interface layer was deposited on the surface of the carbon fiber needle-punched preform using chemical vapor deposition with propane and hydrogen as raw materials. Subsequently, it was placed in a mixture of Ti powder, Si powder, NaCl and KCl in a molar ratio of 3:1:16:16 and held at 1200°C for 1 h at 10 kPa to prepare a Ti3SiC2 interface layer with a thickness of about 1.0 μm on the surface of the carbon fiber needle-punched preform.

[0115] Then, the preform with the deposited Ti3SiC2 interface layer was immersed in the polycarbosilane ceramic precursor for 2 hours, followed by pyrolysis treatment at 1400°C for 3 hours, and the immersion and pyrolysis process was repeated 10 times.

[0116] The sample prepared in this comparative example had a density of 2.17 g / cm³. 3 A ceramic matrix composite material with a Ti3SiC2 interface layer was subjected to a high-temperature bending test according to GJB 10311-2021 standard. The test temperature was 1600°C in air, and the bending strength was 241 MPa. The crack toughness was measured to be 4.3 MPa·m according to GB / T 23806-2009 standard. 1 / 2 .

[0117] Table 1 Performance indicators of ceramic matrix composites obtained in the examples and comparative examples The comparison of the above embodiments and comparative examples shows that the ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer prepared by the present invention exhibits significant performance advantages. The composite materials obtained in the embodiments all show good performance in key performance indicators such as density, flexural strength, and fracture toughness. Especially in a high-temperature air environment of 1600°C, the flexural strength of all embodiments reaches above 314 MPa, generally exceeding 340 MPa, and the fracture toughness of all embodiments is 6.8 MPa·m. 1 / 2 The above generally reach 7.2 MPaˑm 1 / 2 The highest bending strength can reach 389 MPa, and the highest fracture toughness can reach 8.6 MPa·m. 1 / 2In contrast, the comparative example, due to the absence of a certain layer or unreasonable layer thickness, exhibits significantly lower overall performance than the example. This fully demonstrates the rationality and superiority of the three-layer composite interface layer design of the present invention. This composite interface layer can effectively alleviate thermal expansion mismatch stress, significantly improve the high-temperature mechanical properties and oxidation resistance of the composite material, and provide strong technical support for the application of carbon fiber reinforced ceramic matrix composites in extreme high-temperature service environments.

[0118] The parts of this invention not described in detail are well-known to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this invention, and not to limit it; although the 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 depart from the spirit and scope of the technical solutions of the embodiments of this invention.

Claims

1. A method for preparing a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer, characterized in that, The method includes the following steps: (1) A pyrolytic carbon layer is deposited on the fiber surface of the carbon fiber preform to obtain a first preform with a pyrolytic carbon layer deposited on it; (2) A Ti2AlB2 layer is deposited on the surface of the pyrolytic carbon layer to obtain a second preform with a pyrolytic carbon-Ti2AlB2 bilayer deposited on it; (3) A HfB2 layer is deposited on the surface of the Ti2AlB2 layer to obtain a third preform with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer deposited; (4) A ceramic matrix is ​​prepared by impregnation and pyrolysis of the third preform using a ceramic matrix precursor to obtain a ceramic matrix composite material with a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer.

2. The preparation method according to claim 1, characterized in that, In step (1): The carbon fiber preform is a carbon fiber braid, and preferably, the density of the carbon fiber preform is 0.4~0.6 g / cm³. 3 .

3. The preparation method according to claim 1, characterized in that, In step (1): The carbon fiber preform undergoes heat treatment in a vacuum environment before the deposition of the pyrolytic carbon layer to remove surface impurities. Preferably, the heat treatment temperature is 400~500°C and the holding time is 30~40 minutes.

4. The preparation method according to claim 1, characterized in that, In step (1): The deposition process uses methane, hydrogen, and argon as raw materials, and an inert gas is introduced after the deposition is completed to remove the reaction gases. Preferably, the flow rate of methane is 50-150 sccm, the flow rate of hydrogen is 200-300 sccm, and the flow rate of argon is 300-800 sccm. More preferably, the deposition temperature is 1000~1200°C and the deposition pressure is 10. -1 -10 -3 mbar, deposition time 5~15h; More preferably, the thickness of the pyrolytic carbon layer is 0.2~0.5μm; More preferably, the inert gas introduced is argon or nitrogen, with a flow rate of 1000~1500 sccm and a purging time of 15~30 min.

5. The preparation method according to claim 1, characterized in that, In step (2): The deposition process uses titanium tetrachloride, trimethylaluminum or aluminum chloride, diborane, hydrogen and argon as raw materials to deposit the Ti2AlB2 layer on the surface of the pyrolytic carbon layer. After the deposition is completed, an inert gas is introduced to remove the reaction gas. Preferably, the flow rate of titanium tetrachloride is 30-80 sccm, the flow rate of trimethylaluminum or aluminum chloride is 20-60 sccm, the flow rate of diborane is 10-40 sccm, the flow rate of hydrogen is 150-350 sccm, and the flow rate of argon is 300-800 sccm. Preferably, the deposition temperature is 1400~1700°C and the deposition pressure is 10. -1 -10 -3 mbar, deposition time 6~20h; Preferably, the thickness of the Ti2AlB2 layer is 0.2~0.5μm; Preferably, the inert gas introduced is argon or nitrogen, the flow rate is 1000~1500 sccm, and the purging time is 15~30 min.

6. The preparation method according to any one of claims 1 to 5, characterized in that, In step (3): The deposition process uses hafnium tetrachloride, diborane, hydrogen, and argon as raw materials to deposit an HfB2 layer on the surface of the Ti2AlB2 layer, thereby forming a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer on the surface of the carbon fiber. Preferably, the flow rate of hafnium tetrachloride is 40~100 sccm, the flow rate of diborane is 15~50 sccm, the flow rate of hydrogen is 200~300 sccm, and the flow rate of argon is 300~800 sccm. More preferably, the deposition temperature is 1500~1800°C and the deposition pressure is 10. -1 -10 -3 mbar, deposition time 6~20h; More preferably, the thickness of the HfB2 layer is 0.2~0.5μm.

7. The preparation method according to claim 1, characterized in that, In step (4): The ceramic-based precursor is one or more of siloxane, polycarbosilane, or boron carbide; Preferably, vacuum or pressure impregnation is used, with a vacuum degree of 10 for vacuum impregnation. 2 Pa-10 4 Pa, the pressure impregnation pressure is 1×10 6 -5×10 6 The impregnation time is 1~3h; the pyrolysis temperature is 1200~1700°C, and the pyrolysis time is 2~4h.

8. The preparation method according to claim 1, characterized in that, In step (4): Repeat the impregnation and pyrolysis process until the density of the ceramic matrix composite material is 2.0~3.0 g / cm³. 3 .

9. The preparation method according to any one of claims 1 to 8, characterized in that: The deposition described in steps (1) to (3) is carried out by the three-source co-deposition method as follows: after completing step (1), the deposition in step (2) is carried out by switching the raw material gas, and after completing step (2), the deposition in step (3) is carried out by switching the raw material gas.

10. A ceramic matrix composite material having a pyrolytic carbon-Ti2AlB2-HfB2 three-layer composite interface layer, prepared by any one of claims 1 to 9.

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