Double-framework reinforced anti-ablation CMP / C-HfC composite material with coating as well as preparation method and application of double-framework reinforced anti-ablation CMP / C-HfC composite material

Abstract

The invention relates to a double-skeleton reinforced anti-ablation CMP / C-HfC composite material with a coating and a preparation method and application thereof. A CMP / C skeleton is prepared by using mesophase pitch-based carbon fiber as a reinforcement by adopting a chemical vapor deposition method; a reaction infiltration method is adopted, and an HfC ceramic matrix is prepared in a CMP / C framework in a composite mode; the SiC inner layer and the ZrC outer layer are respectively prepared on the surface of CMP / C-HfC by adopting a reactive infiltration or chemical vapor deposition method and a magnetron sputtering process. According to the CMP / C-HfC composite material disclosed by the invention, a high-modulus CMP / C efficient heat transfer channel and a continuous HfC ceramic enhanced network which are of a mutually embedded structure are constructed, so that the force-heat-ablation resistance of the CMP / C-HfC composite material is synchronously improved. Meanwhile, by combining the complementary advantages of ZrC / SiC coating modification in the aspects of oxidation resistance and ablation resistance, the ablation resistance of the material is further improved, and reliable use of the C / C composite material under the ultra-high-temperature service working condition is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal protection of carbon-based or ceramic-based composites, and in particular relates to a dual-skeleton reinforced ablative-resistant C MP / C-HfC composite material, its preparation method and application. Background Art

[0002] When a reentry orbital vehicle performs cross-atmospheric flight, it will generate strong aerodynamic heating, resulting in extremely harsh service conditions (local temperature up to over 3000 °C). Therefore, extremely strict usage and performance requirements are imposed on the ultra-high temperature hot-end materials for constructing the thermal protection system. Carbon / carbon (C / C) composite materials have the characteristics of low density, high specific strength, low thermal expansion and excellent mechanical properties, and they are also the only high-temperature engineering materials that can maintain their mechanical properties without obvious decline or even increase at temperatures above 2000 °C. However, C / C composite materials also face serious problems of intrinsic oxidation and thermal ablation, which have become the key technical bottlenecks restricting their stable service under high-temperature conditions.

[0003] The inventor found through past research that HfC has the highest melting point (3890 °C), extremely low vapor pressure and excellent ablation resistance, and the formed oxidation product HfO2 also has a melting point as high as over 2800 °C, which is one of the most promising ablation-resistant materials at present. However, the introduced third phase or discontinuous ceramics may all have an adverse impact on the mechanical strength of the material. In addition, the above matrix modification methods for C / C composite materials are all based on the passive protection principle of improving the temperature resistance of the material, and there are few practices of reducing the ablation rate by improving the thermal conductivity of the material through this active protection mechanism. At present, carbon / carbon (C MP / C) composite materials with a main reinforcement structure of mesophase pitch-based carbon fibers (MPCF) have outstanding ultra-high thermal conductivity, enabling them to significantly reduce the surface temperature, thermal gradient and ablation rate of the material, and becoming an important development direction for aerospace application materials in recent years. Therefore, it is urgent to explore and construct a new system and innovative structure of fiber-matrix on the basis of the traditional matrix modification concept, aiming to fundamentally solve the problem of performance degradation caused by the introduced HfC. Summary of the Invention

[0004] In view of the above problems, the present invention provides a dual-skeleton reinforced ablative-resistant C MP / C-HfC composite material, its preparation method and application, which can effectively improve the stable thermal protection ability of C / C composite materials under ultra-high temperature service conditions.

[0005] The above object can be achieved by the following technical solutions:

[0006] In the first aspect, the present invention proposes a dual-skeleton reinforced ablative-resistant CMP / C-HfC composite material, specifically, the C MP / C-HfC composite material includes a C MP / C framework with mesophase pitch-based carbon fiber (MPCF) as the reinforcement, and a HfC ceramic matrix embedded in the C MP / C framework; a SiC / ZrC coating is provided on the surface of the C MP / C-HfC composite material;

[0007] The C MP / C framework is composed of mesophase pitch-based carbon fiber and pyrolytic carbon, and has ultra-high modulus and high thermal conductivity characteristics; the HfC ceramic matrix is interlocked with the structure of the C MP / C framework, and has a continuous network structure and ultra-high temperature resistance and ablation resistance; the SiC / ZrC coating is composed of an inner SiC layer and an outer ZrC layer;

[0008] Preferably, the tensile strength of the mesophase pitch-based carbon fiber is 2.6 - 3.4 GPa, the tensile modulus is 600 - 950 GPa, and the thermal conductivity is 600 - 1000 W / m·K. The MPCF is prepared into an MPCF preform through a fine weaving and piercing process, and the volume fraction is 40 - 55%. Then, a C 3 / C framework with a density of 1.2 - 1.4 g / cm MP is obtained through pyrolytic carbon deposition; the volume content of the HfC ceramic matrix relative to the C MP / C-HfC composite material is 20 - 40%, and the prepared C MP / C-HfC composite material has a density of 4.0 - 6.5 g / cm 3 .

[0009] In the second aspect, the present invention provides a preparation method of the above-mentioned coated dual-framework enhanced ablation-resistant C MP / C-HfC composite material, which adopts the following steps:

[0010] S1: Using chemical vapor deposition method and high-temperature graphitization process to prepare a high-modulus and high-thermal conductivity C MP / C framework;

[0011] S2: Using reaction infiltration method to prepare a HfC ceramic matrix in the C MP / C framework, and constructing a C MP / C-HfC composite material strengthened by a dual-framework structure;

[0012] S3: Using reaction infiltration or chemical vapor deposition process to prepare an inner SiC layer on the surface of the C MP / C-HfC composite material;

[0013] S4: Using the magnetron sputtering method, a ZrC outer layer is prepared on the inner surface of the SiC layer to obtain a double-skeleton reinforced anti-ablation C MP / C-HfC composite material.

[0014] The present invention fully combines the complementary advantages of the two in terms of oxidation resistance and ablation prevention, further improves the ablation resistance of the material, and is of great significance for realizing the high-reliability use of C / C composite materials under ultra-high temperature service conditions.

[0015] In a further embodiment of the present invention, S1 specifically includes the steps of:

[0016] S101: The low-modulus carbonized MPCF (CFMP-1600) is arranged in a satin pattern in the X / Y direction, and the polyacrylonitrile carbon fiber is integrally needle-punched in the Z direction to make an intermediate-phase pitch-based carbon fiber preform; the needle-punching pitch is controlled to be 1-5 mm, and the density of the intermediate-phase pitch-based carbon fiber preform is 0.9-0.98 g·cm -3 , and the volume fraction is 40-55%;

[0017] S102: The MPCF preform is placed in a pyrolytic carbon deposition furnace, and nitrogen and propane are introduced to deposit a pyrolytic carbon layer; the deposition temperature is controlled to be 900-1100 °C, the deposition pressure is 0.5-3 kPa, the propane flow rate is 20-120 L / h, the nitrogen flow rate is 60-360 L / h, and the deposition time is 20-80 h. The density of the C MP / C skeleton is 1.2-1.4 g·cm -3 .

[0018] S103: The MPCF preform processed in step S102 is graphitized in an argon atmosphere; the graphitization temperature is controlled to be 2000-3000 °C, and the holding time is 0.5-2.5 h.

[0019] In a further embodiment of the present invention, S2 specifically includes the steps of:

[0020] S201: Weigh Hf powder, graphite powder and sintering aids according to the mass ratio of (10-20):(0.5-3):1, and wet-mill them in a ball mill with ethanol for 2-12 h, and then dry to obtain a uniformly mixed embedded powder; the sintering aids include one or more of Ni, Cu, Al, Ni3C, Al4C3, TiC, Al2O3, SiO2 and Y2O3;

[0021] S202: Place the C MP / C skeleton blank in a hot-pressing graphite mold, and use the embedded powder obtained in step 201 for embedding. The volume ratio of the C MP / C skeleton blank to the embedded powder is 1:(1-2.5);

[0022] S203: Conduct heat treatment in a high-temperature reaction furnace, where the heat treatment temperature is 1600 - 2400 °C, the heat treatment time is 0.5 - 2 h, and the protective atmosphere is argon.

[0023] In a further embodiment of the present invention, S3 specifically includes the steps:

[0024] Steps for preparing the SiC inner layer by reactive infiltration process: Weigh silicon powder, graphite powder, and SiC powder with mass fractions of 40 - 50%, 20 - 30%, and 20 - 40% respectively, and mix and ball mill them for 6 - 12 h to make the grinding uniform and fine to obtain the embedded powder; MP Perform an embedding infiltration reaction on the C / C-HfC composite material. The infiltration reaction temperature is 1750 - 1800 °C, the holding time is 0.5 - 2 h, and the thickness of the obtained SiC inner layer is 10 - 20 μm;

[0025] Alternatively, steps for preparing the SiC inner layer by chemical vapor deposition process: Use trichloromethylsilane (MTS), hydrogen, and argon as reaction gas sources. The MTS flow rate is 50 - 150 g / h, the H2 carrier gas flow rate is 30 - 60 L / h, the H2 dilution gas flow rate is 60 - 180 L / h, and the Ar flow rate is 200 - 400 L / h; The reaction temperature is 1000 - 1200 °C, the atmosphere pressure is 800 - 1500 Pa, the deposition time is 5 - 10 h, and the thickness of the obtained SiC inner layer is 10 - 20 μm.

[0026] In a further embodiment of the present invention, S4 specifically includes the steps: Fix the sample with the SiC inner layer processed in S3 on the copper backplane of the sample holder at the top of the magnetron sputtering reaction chamber, and deposit PVD-ZrC on the sample surface using a high-purity C target and a Zr target under DC excitation; During the implementation process, the C target power is 90 - 130 W, the Zr target power is 60 - 100 W, the deposition pressure is 0.57 - 0.98 Pa, the Ar flow rate is 30 - 70 sccm, the sample rotation speed is 5 - 30 rpm, the target sputtering distance is 80 - 150 mm, the deposition time is 20 - 60 h, and the thickness of the obtained ZrC outer layer is 7 - 20 μm.

[0027] Thirdly, the present invention provides the above-mentioned double-skeleton enhanced ablation-resistant C MP / C-HfC composite material can achieve high-reliability application of C / C composite materials under ultra-high temperature service conditions.

[0028] The technical solution provided by the present invention has the following beneficial effects:

[0029] (1) The present invention proposes to prepare a high-thermal conductivity C / C-HfC composite material modified by the HfC matrix through a reactive infiltration process, and construct a C MP / C-HfC composite materialMP / C-HfC dual-skeleton structure with a high-modulus C having an interpenetrating structure MP / C high-efficiency heat transfer channels and continuous HfC ceramic reinforcement networks to achieve simultaneous improvement in its compatible mechanical-thermal-ablative resistance performance. With the help of HfC x O y -HfO2 oxide skin formed by HfC oxidation, effectively improving the erosion resistance of the material to high-enthalpy heat flux. At the same time, the high-thermal-conductivity C MP / C skeleton can quickly transfer heat, effectively reducing internal heat accumulation in the material, thereby reducing its thermal stress and thermochemical ablation effect.

[0030] (2) Based on the concept of coating-substrate integration, the present invention prepares a coated dual-skeleton enhanced ablative-resistant C MP / C-HfC composite material, whose ablative resistance is further improved. During the oxidation process, the formation of oxygen-blocking SiC x O y and ZrSiO4 pinning phases strengthens the ablative resistance performance and interfacial bonding performance of the coating; the Hf-Si-O glass with a certain composition gradient fills the internal defects of the matrix material, and the Hf-Si-O glass with a specific composition ratio will continue to transform into HfSiO4 in the binary stable phase structure, effectively inhibiting the formation and expansion of matrix cracks.

[0031] The additional aspects and advantages of the present invention will be partly given in the following description, partly become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of the preparation process of the coated dual-skeleton enhanced ablative-resistant C MP / C-HfC composite material of the present invention;

[0033] Figure 2 is the microscopic morphology diagram of the C MP / C-HfC composite material prepared in Example 1 of the present invention;

[0034] Figure 3 is the XRD diagram of the C MP / C-HfC composite material prepared in Example 1 of the present invention;

[0035] Figure 4 is the flexural mechanical strength test diagram of the C MP / C-HfC composite material and the C MP / C skeleton in Example 1 of the present invention;

[0036] Figure 5This is the microscopic morphology diagram of the ZrC / SiC coating in Embodiment 1 of the present invention. Among them, Figure a is the surface microscopic morphology diagram of the SiC inner layer, and b is the cross-sectional microscopic morphology diagram of the C MP / C-HfC composite material, c is the surface microscopic morphology diagram of the ZrC outer layer, and d is the cross-sectional microscopic morphology diagram of the C MP / C-HfC composite material with a ZrC / SiC coating;

[0037] Figure 6 This is the plasma ablation platform and the sample ablation process in the embodiment of the present invention. Detailed implementation manners

[0038] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention. Therefore, they are only used as examples and cannot be used to limit the protection scope of the present invention. Any parameters can be increased or decreased proportionally according to the actual situation.

[0039] Embodiment 1

[0040] This embodiment provides a double-skeleton enhanced ablation-resistant C MP / C-HfC composite material, including the prepared C MP / C skeleton with a density of 1.4 g·cm -3 ; The C MP / C-HfC composite material prepared by compounding within the C MP / C skeleton has a density of 4.7 g·cm -3 ; The SiC inner layer (with a thickness of 11 μm) prepared on the surface of the C MP / C-HfC composite material and the ZrC outer layer (with a thickness of 12 μm) prepared on the SiC inner layer. The preparation method includes the following steps:

[0041] S1: First, the low-modulus carbonized CFMP-1600 carbon fiber is arranged in a satin pattern in the X / Y direction, and the polyacrylonitrile carbon fiber is needled and integrally woven in the Z direction; the needling pitch is controlled to be 3 mm, and the density of the preform is 0.98 g·cm -3 , and the fiber volume fraction is 45%. Secondly, the carbon fiber preform is placed in a high-temperature vacuum furnace, and argon and propylene are introduced to deposit a pyrolytic carbon layer; the deposition temperature is controlled to be 980 °C, the deposition pressure is 1 kPa, the propylene flow rate is 60 L / min, and the nitrogen flow rate is 240 L / h, and the C MP / C skeleton density is 1.2 g·cm -3 ; Finally, the treated preform is graphitized in an argon atmosphere, and the graphitization temperature is controlled to be 3000 °C and the holding time is 0.5 h during the process.

[0042] S2: First, the C MPThe C is processed into a block with dimensions of 10×10×10 mm 3 , ultrasonically cleaned in absolute ethanol, acetone, and deionized water, and dried for later use. Weigh hafnium powder, graphite powder, and Cu sintering aid according to the mass ratio of 18.75:1.25:1, and wet-mill them in a ball mill with ethanol for 4 h. After drying, a uniformly mixed embedded powder is obtained. Secondly, the C MP / C skeleton blank is embedded in a hot-pressed graphite mold using the embedded powder obtained in the previous step. The volume ratio of the C MP / C skeleton blank to the embedded powder is 4:5. Heat treatment is carried out in a high-temperature reaction furnace. The heat treatment temperature is 1800 °C, the heat treatment time is 1.5 h, and the protective atmosphere is argon.

[0043] S3: First, polish and grind the surface of the C MP / C-HfC with 400-mesh and 800-mesh sandpaper for 1 h respectively, then ultrasonically clean it in absolute ethanol, acetone, and deionized water, and dry it for later use. Secondly, weigh Si powder, graphite powder, and SiC powder according to the mass fractions of 50%, 30%, and 20% respectively, and mix and ball-mill them for 6 - 12 h to make the grinding uniform and fine to obtain the embedded powder. Embed and infiltrate the C MP / C-HfC composite material. The infiltration reaction temperature is 1750 °C, the holding time is 1 h, and the thickness of the obtained SiC inner layer is 11 μm.

[0044] S4: First, use a high-temperature adhesive to fix the coated sample with the prepared intermediate layer on the copper backplane of the sample holder at the top of the magnetron sputtering reaction chamber. Heat the sample holder to 300 °C at a rate of 5 °C / min and keep it at a constant temperature. Adjust the rotation speed to 20 rpm and the sputtering distance to 115 mm. Before the formal deposition, only turn on the Zr target for deposition to improve the adhesion of the coating. Control the starting glow pressure to be 2 Pa, the Ar flow rate to be 30 sccm, and the starting glow sputtering time to be 5 min. Then, simultaneously deposit PVD-ZrC on the sample surface using a high-purity C target and a Zr target excited by direct current. Control the power of the C target and the Zr target to be 110 W and 70 W respectively, the deposition pressure to be 0.57 Pa, and the continuous deposition time to be 40 h to make the thickness of the ZrC outer layer reach about 12 μm.

[0045] Example Two

[0046] This example provides a double-skeleton enhanced ablation-resistant C MP / C-HfC composite material, including the prepared C MP / C skeleton with a density of 1.2 g·cm -3 ; The C MP / C-HfC composite material prepared by in-situ composite in the C MP / C skeleton, with a density of 5.2 g·cm -3; Preparation of an inner SiC layer (with a thickness of 15 μm) on the C MP / C-HfC composite material surface and an outer ZrC layer (with a thickness of 12 μm) prepared on the inner SiC layer. The preparation method includes the following steps:

[0047] S1: First, satin-weave the low-modulus carbonized CFMP-1600 carbon fibers in the X / Y directions and integrally needle-weave the polyacrylonitrile carbon fibers in the Z direction; control the needle punching spacing to be 3 mm and the density of the preform to be 0.90 g·cm -3 , and the fiber volume fraction to be 40%. Secondly, place the carbon fiber preform in a high-temperature vacuum furnace, introduce argon and propylene, and deposit a pyrolytic carbon layer; control the deposition temperature to be 980 °C, the deposition pressure to be 1 kPa, the propylene flow rate to be 40 L / min, the nitrogen flow rate to be 200 L / h, and the C MP / C skeleton density to be 1.2 g·cm -3 ; Finally, graphitize the treated preform in an argon atmosphere, and control the graphitization temperature to be 3000 °C and the holding time to be 0.5 h during the process.

[0048] S2: First, process the C MP / C into a block of 10×10×10 mm 3 , ultrasonically clean it in absolute ethanol, acetone, and deionized water, and dry it for standby. Weigh Hf powder, graphite powder, and Ni sintering aid according to the mass ratio of 15:3:1, and perform wet grinding in a ball mill with ethanol for 5 h, and obtain a uniformly mixed embedded powder after drying. Secondly, place the C MP / C skeleton blank in a hot-pressing graphite mold, and embed it with the embedded powder obtained in the previous step. The volume ratio of the C MP / C skeleton blank to the embedded powder is 1:1.5. Perform heat treatment in a high-temperature reaction furnace, with the heat treatment temperature being 2000 °C, the heat treatment time being 1.5 h, and the protective atmosphere being argon.

[0049] S3: First, polish and grind the C MP / C-HfC surface with 400-mesh and 800-mesh sandpapers for 1 h respectively, then ultrasonically clean it in absolute ethanol, acetone, and deionized water, and dry it for standby. Secondly, place it in a deposition furnace, and use trichloromethylsilane, hydrogen, and argon as reaction gas sources. The MTS flow rate is 100 g / h, the H2 carrier gas flow rate is 48 L / h, the H2 dilution gas flow rate is 80 L / h, and the Ar flow rate is 360 L / h; the reaction temperature is 1100 °C, the atmospheric pressure is 1000 Pa, the deposition time is 8 h, and the obtained inner SiC layer thickness is 15 μm.

[0050] S4: First, use a high-temperature adhesive to fix the coated sample with the prepared intermediate layer on the copper backplane of the sample holder at the top of the magnetron sputtering reaction chamber. Heat the sample holder to 300 °C at a rate of 5 °C / min and keep it at a constant temperature. Adjust the rotation speed to 15 rpm and the sputtering distance to 115 mm. Before the formal deposition, only turn on the Zr target for deposition to improve the adhesion of the coating. Control the glow pressure to 2 Pa, the Ar flow rate to 50 sccm, and the glow sputtering time to 5 min. Then, simultaneously deposit PVD-ZrC on the surface of the sample using a high-purity C target and a Zr target under DC excitation. Control the power of the C target and the Zr target to be 100 W and 90 W respectively, the deposition pressure to 0.79 Pa, and the continuous deposition time to 40 h, so that the thickness of the outer ZrC layer reaches about 15 μm.

[0051] The process for preparing the double-skeleton reinforced ablation-resistant C MP / C-HfC composite material is as follows Figure 1 shown. Conduct SEM characterization tests on the C MP / C-HfC composite material. The results are as follows Figure 2 shown, indicating that the C MP / C-HfC composite material has a dense interlocked structure, and the ceramic phase and the carbon phase are tightly combined; Figure 3 is the XRD result of the C MP / C-HfC composite material, indicating that the material mainly contains a carbon phase and an HfC ceramic component; Figure 4 indicates that the prepared C MP / C-HfC composite material has greatly improved mechanical properties compared to the C MP / C composite material, mainly due to its double-skeleton structure; Figure 5 The shown layered structure of RMI-SiC and ZrC coatings is dense and complete, and the interfacial bonding is good, proving that the outer ZrC / SiC coating and the C MP / C-HfC composite material matrix have good physical and chemical compatibility.

[0052] Table 1 Statistical table of test results of the double-skeleton reinforced ablation-resistant C MP / C-HfC composite material

[0053] Embodiment Embodiment 1 Embodiment 2 <![CDATA[Mass ablation rate (mg·s -1 )]]> 0.49 0.26 <![CDATA[Linear ablation rate (μm·s -1 )]]> -1.17 -1.44

[0054] It should be noted that in addition to the parameters in the preparation processes involved in the above Examples 1 to 2, it is also feasible to select other preparation parameters.

[0055] The generally understood ordinary meaning; the numerical values mentioned in the embodiments of the present invention are only of an exemplary nature, and the remaining numerical values should also belong to the present invention; the steps involved in the embodiments of the present invention have no sequence, so changing the order of the steps also belongs to the scope of the present invention. It should be noted that unless otherwise specified, the professional terms involved in the present invention should be those of the technical workers in this field.

Claims

1. A coated dual-skeleton reinforced anti-ablative C MP / C-HfC composite material, characterized in that: The said C MP / C-HfC composite material comprises a C MP / C skeleton reinforced with mesophase pitch-based carbon fibers and a HfC ceramic matrix embedded in the C MP / C skeleton; a SiC / ZrC coating is provided on the surface of the C MP / C-HfC composite material; The C MP / C skeleton is composed of mesophase pitch-based carbon fiber and pyrolytic carbon, and has ultra-high modulus and high thermal conductivity characteristics; the HfC ceramic matrix and the C MP / C skeleton are interlocked in structure, have a continuous network structure and ultra-high temperature resistance and ablation resistance; the SiC / ZrC coating is composed of an inner SiC layer and an outer ZrC layer.

2. A coated double-skeleton reinforced anti-ablative C MP / C-HfC composite material, characterized in that: The tensile strength of the mesophase pitch-based carbon fiber is 2.6 to 3.4 GPa, the tensile modulus is 600 to 950 GPa, and the thermal conductivity is 600 to 1000 W / m·K. The mesophase pitch-based carbon fiber preform is prepared by a fine weaving and piercing process, and the volume fraction is 40 to 55%; then a C 3 / C skeleton with a density of 1.2 to 1.4 g / cm MP is obtained by pyrolytic carbon deposition; the volume content of the HfC ceramic matrix relative to the C MP / C-HfC composite material is 20 to 40%, and the prepared C MP / C-HfC composite material has a density of 4.0 to 6.5 g / cm 3 .

3. The preparation method of the coated double-skeleton reinforced anti-ablative C MP / C-HfC composite material, characterized in that Adopt the following steps: S1: Prepare a high modulus and high thermal conductivity C MP / C skeleton by chemical vapor deposition method and high temperature graphitization process; S2: Using the reaction infiltration method, within the C MP / C skeleton, a HfC ceramic matrix is prepared by compounding to obtain a C MP / C-HfC composite material; S3: Adopt the reaction infiltration or chemical vapor deposition process to prepare an inner SiC layer on the surface of the C MP / C-HfC composite material; S4: Using the magnetron sputtering method, a ZrC outer layer is prepared on the inner surface of the SiC to obtain a double-skeleton reinforced anti-ablative C MP / C-HfC composite material.

4. A method for preparing a dual-skeleton reinforced anti-ablative C MP / C-HfC composite material with a coating, characterized in that The step S1 includes: S101: The mesophase pitch-based carbon fiber is arranged in a satin weave in the X / Y direction, and the polyacrylonitrile-based carbon fiber is needled and integrally woven in the Z direction to produce a mesophase pitch-based carbon fiber preform. The needling pitch is controlled to be 1-5 mm, and the density of the mesophase pitch-based carbon fiber preform is 0.9-0.98 g·cm -3 , and the volume fraction is 40-55%; S102: Place the mesophase pitch-based carbon fiber preform in a pyrolytic carbon deposition furnace, introduce nitrogen and propane, and deposit a pyrolytic carbon layer. Control the deposition temperature at 900 - 1100 °C, the deposition pressure at 0.5 - 3 kPa, the propane flow rate at 20 - 120 L / h, the nitrogen flow rate at 60 - 360 L / h, and the deposition time at 20 - 80 h. The density of the C MP / C skeleton is 1.2 - 1.4 g·cm -3 ; S103: Graphitize the mesophase pitch-based carbon fiber preform processed in step S102 in an argon atmosphere; control the graphitization temperature to be 2000 - 3000 °C and the heat preservation time to be 0.5 - 2.5 h.

5. A method for preparing a double-skeleton reinforced anti-ablative C MP / C-HfC composite material with a coating, characterized in that, The step S2 includes: S201: Weigh Hf powder, graphite powder and sintering aids according to the mass measurement ratio of (10 - 20):(0.5 - 3):1, and perform wet grinding in a ball mill with ethanol for 2 - 12 h. After drying, obtain uniformly mixed embedding powder; the sintering aids include one or more of Ni, Cu, Al, Ni3C, Al4C3, TiC, Al2O3, SiO2 and Y2O3; S202: Place C MP / C skeleton blank in a hot-pressed graphite mold, and use the embedding powder obtained in step 201 for embedding. C MP / The volume ratio of the C skeleton blank to the embedding powder is 1:(1 - 2.5); S203: Perform heat treatment in a high-temperature reaction furnace, with the heat treatment temperature being 1600 - 2400 °C, the heat treatment time being 0.5 - 2 h, and the protective atmosphere being argon.

6. A method for preparing a coated double-skeleton reinforced ablative C MP / C-HfC composite material, characterized in that The specific S3 includes the steps of: taking the above-prepared C MP The surface of the / C-HfC composite material is machined flat, cleaned and dried; Steps for preparing the SiC inner layer by reactive infiltration process: Weigh silicon powder, graphite powder and SiC powder with mass fractions of 40 - 50%, 20 - 30% and 20 - 40% respectively, and mix and ball-mill them for 6 - 12 h to make the grinding uniform and fine to obtain the embedded powder; Carry out the MP infiltration reaction on the C / C-HfC composite material. The infiltration reaction temperature is 1750 - 1800 °C, and the heat preservation time is 0.5 - 2 h. The thickness of the obtained SiC inner layer is 10 - 20 μm; Alternatively, adopt the steps of preparing the SiC inner layer by chemical vapor deposition process, using trichloromethylsilane, hydrogen and argon as reaction gas sources; the flow rate of trichloromethylsilane is 50 - 150 g / h, the flow rate of H2 carrier gas is 30 - 60 L / h, the flow rate of H2 dilution gas is 60 - 180 L / h, and the flow rate of Ar is 200 - 400 L / h; the reaction temperature is 1000 - 1200 °C, the atmospheric pressure is 800 - 1500 Pa, the deposition time is 5 - 10 h, and the thickness of the obtained SiC inner layer is 10 - 20 μm.

7. A method for preparing a coated double-skeleton reinforced anti-ablative C MP / C-HfC composite material, characterized in that The step S4 specifically includes the steps of: Fix the material with the SiC inner layer processed in S3 on the copper backplane of the sample holder at the top of the magnetron sputtering reaction chamber, and deposit PVD-ZrC on the sample surface using a high-purity C target and a Zr target excited by direct current; The power of the C target is 90 - 130 W, the power of the Zr target is 60 - 100 W, the substrate temperature is 100 - 300 °C, the deposition pressure is 0.57 - 0.98 Pa, the Ar flow rate is 30 - 70 sccm, the sample rotation speed is 5 - 30 rpm, the target sputtering distance is 80 - 150 mm, the deposition time is 20 - 60 h, and the thickness of the obtained ZrC outer layer is 7 - 20 μm.

8. A coated double-skeleton reinforced anti-ablative C MP / C-HfC composite material can achieve high-reliability applications of C / C composite materials under ultra-high temperature service conditions.

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