A method for preparing an ultrahigh-temperature ceramic matrix modified and coating integrated carbon-based composite material

Abstract

This invention discloses a method for preparing an integrated ultra-high temperature ceramic matrix modification and coating carbon-based composite material, belonging to the technical field of integrated matrix modification and coating carbon-based composite material preparation. This invention involves layering two functional materials onto a low-density carbon / carbon (C / C) surface. The inner layer of melt-infiltrating powder is used for matrix modification, while the outer layer of coating powder is used for in-situ coating formation. Finally, pressure is applied under vacuum using the SPS process, causing the silicide alloy melt to infiltrate into the C / C matrix with molten salt assistance to generate carbides. Simultaneously, the outer layer powder is transformed in-situ into a dense ceramic coating. This method, based on SPS technology, achieves matrix modification and in-situ coating formation simultaneously in a one-step process. The method controls the coating thickness by adjusting the powder quality and utilizes melt infiltration and interfacial mechanical interlocking to achieve a strong interfacial bond between the coating and the modified matrix.

Description

Technical Field

[0001] This invention belongs to the field of preparation technology of carbon-based composite materials with integrated matrix modification and coating, and specifically relates to a method for preparing carbon-based composite materials with integrated ultra-high temperature ceramic matrix modification and coating. Background Technology

[0002] Carbon / carbon (C / C) composites, with their superior high-temperature mechanical properties and thermal stability, have shown significant application potential in high-temperature thermal structural components in the aerospace field. However, C / C composites are prone to oxidation and ablation in high-temperature aerobic environments, leading to a sharp degradation of material properties and limiting their further application. To address this issue, existing technologies mainly employ two strategies: matrix modification (improving the intrinsic ablation resistance of the matrix by introducing antioxidants) and surface coating (isolating oxygen erosion through an external ceramic coating). However, both strategies have significant limitations—matrix modification, due to partial matrix exposure, cannot completely block oxygen diffusion, while coating technology is limited by the difference in thermal expansion coefficients between the matrix and the coating, making it prone to interfacial cracking or even peeling during thermal shock or ablation. To overcome the bottleneck of single technologies, researchers have proposed a synergistic protection concept integrating matrix modification and coating to achieve overall thermal protection of the material.

[0003] CN112624801B reports a method for modifying C / C composite materials using (SiCNW) / (ZrC matrix-coating integrated) technology. By pre-preparing a SiC nanowire framework, a ZrC (SiC) coating can be formed on the material surface simultaneously with the preparation of the ZrC modified matrix via precursor impregnation pyrolysis. This method enables the ZrC (SiC) ceramic coating to be integrally formed with the doped matrix, effectively blocking the erosion of the matrix by oxygen atmosphere and high-speed particles, reducing the oxidative activity of the matrix, and mitigating the mismatch in thermal expansion coefficients between the matrix and the coating, thus improving the ablation resistance of the C / C composite material from the inside out. However, this method requires multiple high-temperature heat treatments, resulting in a lengthy preparation cycle, and the coating thickness is difficult to control precisely.

[0004] Reference 1, "Liu CX, Su ZA, Huang QZ, Chen JX, Yang X, Cao LX, Yin T, Zhong P, Ablation behavior of ZrC-SiC coated C / C-ZrC-SiC composites prepared by precursor infiltration pyrolysis combined with reactive melt infiltration, Journal of Alloys and Compounds, 597 (2014) 236-242", describes the preparation of C / C-ZrC-SiC composites with a ZrC-SiC coating using a precursor infiltration pyrolysis method combined with reactive melt infiltration, exhibiting relatively excellent ablation resistance. However, this method involves repeating the precursor infiltration pyrolysis process nine times and also incorporates reactive melt infiltration, resulting in a complex preparation process and a long preparation cycle.

[0005] Reference 2, “Xie J, Jia YJ, Zhao ZG, Li KZ, Sun GD, Li H, Su XH, A ZrC-SiC / SiC multilayer anti-ablation coating for ZrC modified C / C composites, Vacuum, 157 (2018) 324-331”, describes the preparation of C / C-ZrC composites with ZrC-SiC outer coating and SiC inner coating by a precursor impregnation pyrolysis method combined with supersonic atmospheric plasma spraying. Although strong interfacial bonding was achieved, the method has high preparation cost and complicated preparation process. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an integrated carbon-based composite material with ultra-high temperature ceramic matrix modification and coating, so as to solve the problems of complicated process and long process cycle in the preparation of composite materials for matrix modification and coating in the prior art.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for preparing an integrated carbon-based composite material with ultra-high temperature ceramic matrix modification and coating includes the following steps:

[0009] S1, lay coating powder in SPS mold, lay melt-infiltrating powder on the coating powder, place low-density C / C composite material on melt-infiltrating powder, lay melt-infiltrating powder on the upper surface of C / C composite material, and lay coating powder on the upper surface of melt-infiltrating powder.

[0010] The infiltration powder is a mixture of silicide alloy powder, molten salt, and catalyst; the coating powder is a mixture of silicide alloy powder, carbon powder, Al2O3, and catalyst powder.

[0011] S2, the mold is subjected to pressure and heating heat treatment by SPS, and after cooling, an integrated carbon-based composite material is obtained.

[0012] A further improvement of the present invention is that:

[0013] Preferably, in S1, the density of the low-density C / C composite material is 1.1~1.4 g / cm³. 3 ...

[0014] Preferably, in S1, the silicide alloy powder is one or more of HfSi2, ZrSi2, TiSi2, TaSi2, and NbSi2 powders.

[0015] Preferably, in S1, the molten salt is one or more of CaCl2, NaCl, and KCl powder.

[0016] Preferably, in S1, the catalyst is elemental iron or a compound thereof, elemental nickel or a compound thereof.

[0017] Preferably, in S1, during the preparation of the melt-infiltrated powder, the silicide alloy powder and molten salt are mixed by a ball mill, a catalyst is added to the mixed powder, and the powder is then ground to obtain the melt-infiltrated powder.

[0018] Preferably, in S1, the coating powder is prepared by mixing silicide alloy powder, carbon powder and Al2O3 in a ball mill, adding a catalyst to the mixed powder, and grinding to obtain the coating powder.

[0019] Preferably, in S1, the mass ratio of silicide alloy powder to molten salt in the melt-infiltrating powder is 6:1 to 10:1.

[0020] Preferably, in S1, the molar ratio of the silicide alloy powder, carbon powder and Al2O3 powder in the coating powder is 30:10:1 to 40:20:1.

[0021] Preferably, in S2, during the pressurization and heating process, the pressure is 6~10kN; the heat treatment temperature is 1500~2100℃; and the holding time is 30~120min.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention discloses a rapid preparation method for an integrated ultra-high temperature ceramic matrix modification and coating carbon-based composite material. The method involves layering two functional materials onto a low-density carbon / carbon (C / C) surface. The inner layer of melt-infiltrating powder is used for matrix modification, while the outer layer of coating powder is used for in-situ coating formation. Finally, pressure is applied under vacuum using the SPS process, causing the silicide alloy melt to infiltrate into the C / C matrix with molten salt assistance to generate carbides. Simultaneously, the outer layer powder is transformed in-situ into a dense ceramic coating. Based on SPS technology, matrix modification and in-situ coating formation are achieved simultaneously in a one-step process. Because the main coating material (carbon powder + silicon alloy powder) is of the same type as the matrix and modification materials (both including carbon and silicon alloy), the melting and infiltration process of the composite material and the reaction of the coating material itself can occur simultaneously at the same heating temperature. As the inner layer of melt-infiltrating powder infiltrates, the materials in the coating powder can react on their own. In the later stages of the coating reaction, the coating itself can partially react with the C / C matrix material, forming a strong bond. This method controls the coating thickness by adjusting the powder quality and achieves strong interfacial bonding between the coating and the modified substrate through melt penetration and interfacial mechanical interlocking (at 4.2 MW / M). 2 (The coating showed no significant peeling after continuous ablation with an oxyacetylene flame for 500 seconds). Compared to traditional stepwise processes, this method fully leverages the advantages of SPS equipment, shortening the preparation cycle to 1-2 hours. It simultaneously achieves substrate modification and in-situ coating formation in a one-step process, simplifying the operation, eliminating multiple complex steps, significantly improving process efficiency, and reducing preparation costs. This method utilizes melt penetration and interfacial mechanical bonding to achieve strong interfacial adhesion between the coating and the modified substrate, making it suitable for the efficient integrated preparation of ceramic-modified C / C and ceramic coatings, and possessing significant engineering application value. The method of this invention has the following advantages:

[0024] 1. This method can complete the preparation of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating in just one step. The matrix is ​​modified by melting and infiltrating powder on the side close to the matrix, and the coating is prepared in situ by melting and infiltrating powder on the side away from the matrix. Strong and tough interfacial bonding is achieved through pressure and melting and infiltrating process.

[0025] 2. Adding molten salt to the inner layer of infiltrating powder can accelerate the infiltration of silicon alloy modified powder and prevent the silicon alloy from sintering before it is infiltrated into the composite material. On the other hand, adding Al2O3 powder to the outer layer of coating powder can serve as a raw material for the outer coating reaction and as a sintering aid to promote the sintering of the surface coating.

[0026] 3. Due to the small mold size of SPS, the powder is stacked and fixed, and is not easy to move. Therefore, the coating thickness can be controlled by adjusting the powder quality, and the composition and thickness of the coating are highly controllable.

[0027] 4. The high-throughput process characteristics of this method support the rapid screening and optimization of coating components and modifying elements, thus accelerating the material development cycle. Attached Figure Description

[0028] Figure 1 This is a schematic diagram showing the stacking order of raw materials in the SPS mold before final heat treatment.

[0029] Figure 2 Macroscopic and microscopic structures of the samples prepared in Example 1: (a) after 4.2 MW / M 2 (a) Macroscopic photographs of the sample before and after continuous oxyacetylene flame ablation for 500 s; (b) XRD pattern of the sample surface; (c)-(i) SEM images of the sample cross section;

[0030] Figure 3 The macroscopic and microscopic structures of the samples prepared in Example 2 are shown below: (a) macroscopic photograph of the sample; (b) XRD pattern of the sample surface; (c) and (d) SEM images of the sample cross-section.

[0031] Figure 4 The macroscopic and microscopic structures of the samples prepared in Example 3 are shown: (a) macroscopic photograph of the sample; (b) XRD pattern of the sample surface; (c) and (d) SEM images of the sample cross sections. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings:

[0033] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0034] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0035] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0036] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0037] As the background art points out, traditional manufacturing processes integrating matrix modification and coating typically involve two steps: ceramic matrix modification and ceramic coating formation. Therefore, the cumbersome preparation process and the interfacial bonding between the coating and the matrix are the most concerning issues. This invention proposes a rapid preparation method for an ultra-high temperature ceramic matrix-modified and coating-integrated carbon-based composite material, based on SPS technology, achieving simultaneous matrix modification and in-situ coating generation in a one-step process. The core process includes: ball milling and mixing a silicide alloy with a molten salt system and a carbon powder-Al2O3 composite system to form an inner matrix modification powder and an outer coating powder. The two powders are then mixed with an iron / nickel-based catalyst in a specific ratio, and the inner modification powder and outer coating powder are sequentially deposited on a low-density C / C surface. This promotes coating sintering and catalyzes the in-situ generation of nano-toughening phases to optimize material properties. A functional layered structure is then constructed. The assembled mold is placed in an SPS furnace, and high-temperature heat treatment is performed by setting appropriate temperature and pressure programs. The silicide alloy melt, aided by the flow of molten salt at high temperatures, reacts with pyrolytic carbon in the C / C matrix under low viscosity to generate carbides, thus modifying the matrix. Simultaneously, the outer silicide alloy reacts in situ with carbon powder or Al2O3 to form a dense carbide / oxide / silicide ceramic coating. Finally, removing any residual graphite paper from the surface yields a tightly bonded matrix-coating integrated composite material, with the coating thickness precisely controlled by the amount of powder added.

[0038] This invention discloses a method for preparing an integrated carbon-based composite material with ultra-high temperature ceramic matrix modification and coating, comprising the following steps:

[0039] Step 1: Ultrasonically clean the low-density C / C composite material with deionized water and dry it in a far-infrared drying oven for 15-20 hours;

[0040] Step 2: Mix silicide alloy powder and molten salt in a ball mill at a certain ratio to obtain powder A;

[0041] Step 3: The silicide alloy powder, carbon powder, and Al2O3 are put into a ball mill in a certain proportion for ball milling and mixing to obtain powder B;

[0042] Step 4: Mix powder A and catalyst in a mortar in a certain proportion to obtain powder C, which is the melt infiltration powder; mix powder B and catalyst in a mortar in a certain proportion to obtain powder D, which is the coating powder.

[0043] Step 5: Evenly spread a certain mass of powder C on the top and bottom of the low-density C / C obtained in step 1;

[0044] Step 6: Evenly spread a certain mass of powder D on the outside of the powder laid in step 5 and place it in the SPS mold, so that the raw materials in the mold are arranged from top to bottom as follows: powder D-powder C-low density C / C-powder C-powder D;

[0045] Step 7: Place the assembled mold in the SPS furnace, set the pressure and temperature program for high-temperature heat treatment, and remove it after cooling.

[0046] Step 8: Use sandpaper to polish and clean the residual graphite paper on the upper and lower surfaces and around the sample to obtain a carbon-based composite material with integrated ultra-high temperature ceramic matrix modification and coating.

[0047] In some embodiments of the present invention, the low-density C / C density in step 1 is 1.1~1.4 g / cm³. 3 .

[0048] In some embodiments of the present invention, the silicide alloy powder in steps 2 and 3 can be one or more of HfSi2, ZrSi2, TiSi2, TaSi2, and NbSi2 powders.

[0049] The molten salt mentioned in step 2 includes one or more of CaCl2, NaCl, and KCl powder. The addition of molten salt can lower the melting point of the infiltrating powder as a whole, enhance the fluidity of the infiltrating powder, and prevent the silicide alloy powder from sintering and agglomerating before it infiltrates into the interior.

[0050] In some embodiments of the present invention, the catalyst in step 4 comprises elemental iron or its compounds, elemental nickel or its compounds, specifically ferrous sulfate or nickel nitrate hexahydrate; the catalyst is suitable for both melt-infiltrating powders and coating powders.

[0051] In some embodiments of the present invention, the mass ratio of silicide alloy powder to molten salt in step 2 is 6:1 to 10:1.

[0052] In some embodiments of the present invention, the molar ratio of silicide alloy powder, carbon powder and Al2O3 in step 3 is 30:10:1 to 40:20:1. By controlling the molar ratio of silicide alloy powder, carbon powder and Al2O3, the proportion of the product, such as the content of silicide, oxide and carbide, can be controlled.

[0053] In some embodiments of the present invention, the mass ratio of process powder to catalyst in step 4 is 200:1 to 500:1.

[0054] In some embodiments of the present invention, the pressure procedure described in step 7 involves applying a pressure of 6 to 10 kN throughout the process, and the infiltration rate can be controlled by controlling the process pressure.

[0055] In some embodiments of the present invention, the heating and cooling process in step 7 is carried out in a vacuum environment. The heating rate is 400-500°C / min below 1500°C and 100-200°C / min above 1500°C. The temperature is raised to 1500-2100°C, and the holding time is 30-120 minutes. In this invention, by setting this heating temperature, the reaction formation of the coating and the infiltration of the melting and infiltrating material can occur simultaneously. At the same time, a gradient temperature rise method is used to provide sufficient time for the melting and infiltrating powder to flow and penetrate.

[0056] For example, the initial heating temperature can be 400℃ / min, 450℃ / min, and 500℃ / min, the subsequent heating temperature can be 100℃ / min, 150℃ / min, and 200℃ / min, and the total heating temperature can be 1500℃, 1600℃, 1700℃, 1800℃, 1900℃, 2000℃, and 2100℃. The holding time can be 30 min, 50 min, 80 min, 100 min, and 120 min.

[0057] A carbon-based composite material integrating ultra-high temperature ceramic matrix modification and coating, prepared by any of the methods described above.

[0058] The following description, in conjunction with specific embodiments, provides further details.

[0059] Example 1

[0060] Step 1: Use deionized water for ultrasonic cleaning of a sample with dimensions of Φ29mm × 10mm and a density of 1.28g / cm³. 3 The low-density C / C was dried in a far-infrared drying oven at 100℃ for 20 hours.

[0061] Step 2: Pour HfSi2 and ZrSi2 in a molar ratio of 1:1 and mixed powders of CaCl2 and NaCl in a mass ratio of 8:1 into a ball mill jar and ball mill them. The ball-to-material ratio is 2:1, the ball milling speed is 420 r / min, and after ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder A1.

[0062] Step 3: Mix HfSi2 and ZrSi2 in a molar ratio of 1:1 with carbon powder and Al2O3 in a molar ratio of 36:17:1 and pour the mixture into a ball mill jar. Use a ball mill to ball mill the mixture, with a ball-to-material ratio of 2:1 and a milling speed of 420 r / min. After milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder B1.

[0063] Step 4: Mix powder A1 and powder B1 with nickel powder in a mortar at a mass ratio of 300:1 to obtain powder C1 and powder D1.

[0064] Step 5: Evenly spread 7.35g of powder C1 on both the top and bottom of the low-density C / C.

[0065] Step 6: Continue to evenly spread 3.99g of powder D1 outside the powder laid in step 5, place it above the lower punch of the SPS mold, wrap the low density C / C and powder around the graphite paper, place the graphite paper with a size of Φ30mm in the area where the powder contacts the upper and lower punches, and finally press in the upper punch.

[0066] Step 7: Before final heat treatment, the raw materials in the mold are arranged from top to bottom as follows: powder D1-powder C1-low density C / C-powder C1-powder D1. Place the assembled mold in an SPS furnace with a pressure of 7kN. Heat to 1500℃ in a vacuum environment at a heating rate of 450℃ / min, then continue heating to 1800℃ at a heating rate of 200℃ / min. Hold for 60 minutes, then cool to room temperature at a cooling rate of 200℃ / min and remove.

[0067] Step 8: Use sandpaper to polish and clean the residual graphite paper on the upper and lower surfaces and around the sample to obtain the (Zr, Hf)C-SiC modified C / C composite material with ZrC-HfC-ZrO2-HfO2-SiO2 multiphase coating.

[0068] See Figure 2 The sample was subjected to 4.2 MW / M 2After continuous 500s of oxyacetylene flame ablation, the coating showed no significant peeling (Figure (a)), demonstrating excellent adhesion. The XRD pattern of the sample surface, as shown in Figure (b), reveals that the coating contains ZrC, HfC, ZrO2, HfO2, and SiO2. The cross-sectional SEM images are shown in Figures (c)-(i). Figures (c)-(e) show a continuous and dense coating formed on the substrate surface, with a thickness of ~175µm. The coating and substrate exhibit mechanical interlocking and tight bonding. Figure (f) shows an internal SEM image of the substrate, revealing a high ceramic content and dense structure. Figures (g)-(i) show SEM images from the coating surface to the coating-substrate interface, demonstrating fine grains in the coating.

[0069] Example 2

[0070] Step 1: Use deionized water for ultrasonic cleaning of a sample with dimensions of Φ29mm × 10mm and a density of 1.34g / cm³. 3 The low-density C / C was dried in a far-infrared drying oven at 100℃ for 15~20h.

[0071] Step 2: Pour HfSi2 and ZrSi2 in a molar ratio of 1:1 and mixed powders of CaCl2 and NaCl in a mass ratio of 9:1 into a ball mill jar and ball mill them. The ball-to-material ratio is 2:1, the ball milling speed is 420 r / min, and after ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder A2.

[0072] Step 3: Mix HfSi2 and ZrSi2 in a molar ratio of 1:1 with carbon powder and Al2O3 in a molar ratio of 40:15:1 and pour the mixture into a ball mill jar. Use a ball mill to ball mill the mixture, with a ball-to-material ratio of 2:1 and a milling speed of 420 r / min. After milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder B2.

[0073] Step 4: Mix powder A2 and powder B2 with nickel powder in a mortar at a mass ratio of 400:1 to obtain powder C2 and powder D2.

[0074] Step 5: Evenly spread 6.42g of powder C2 on both the top and bottom of the low-density C / C.

[0075] Step 6: Continue to evenly spread 1.00g of powder D2 outside the powder laid in step 5, place it above the lower punch of the SPS mold, wrap the low density C / C and powder around the graphite paper, place a Φ30mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press in the upper punch.

[0076] Step 7: Before final heat treatment, the raw materials in the mold are arranged from top to bottom as follows: powder D2 - powder C2 - low density C / C - powder C2 - powder D2. Place the assembled mold in an SPS furnace with a pressure of 8 kN. Heat to 1500°C in a vacuum environment at a heating rate of 450°C / min, then continue heating to 1650°C at a heating rate of 200°C / min. Hold for 30 minutes, then cool to room temperature at a cooling rate of 200°C / min and remove.

[0077] Step 8: Use sandpaper to polish and clean the residual graphite paper on the upper and lower surfaces and around the sample to obtain the (Zr, Hf)C-SiC modified C / C composite material with ZrC-HfC-ZrO2-HfO2-ZrSi2-HfSi2 multiphase coating.

[0078] Its macroscopic photos are as follows Figure 3 As shown in Figure (a), the coating is uniformly applied to the surface of the composite material. Its surface XRD pattern is as follows: Figure 3 As shown in Figure (a), the coating contains ZrC, HfC, ZrO2, HfO2, ZrSi2, and HfSi2. Its cross-sectional SEM images are shown in Figures (c) and (d). Figure 3 Figure (a) shows that a continuous and dense coating was formed on the material surface with a thickness of ~40µm. The coating has good interfacial bonding with the substrate. Figure (d) is a SEM image of the interior of the substrate, which shows that the substrate has a high ceramic content and a dense structure.

[0079] Example 3

[0080] Step 1: Use deionized water for ultrasonic cleaning of a sample with dimensions of Φ29mm × 10mm and a density of 1.32g / cm³. 3 The low-density C / C was dried in a far-infrared drying oven at 100℃ for 15~20h.

[0081] Step 2: Pour HfSi2 and ZrSi2 in a molar ratio of 1:1 and mixed powders of CaCl2 and NaCl in a mass ratio of 7:1 into a ball mill jar and ball mill them. The ball-to-material ratio is 2:1, the ball milling speed is 420 r / min, and after ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder A3.

[0082] Step 3: Mix HfSi2 and ZrSi2 in a molar ratio of 1:1 with carbon powder and Al2O3 in a molar ratio of 40:20:1 and pour the mixture into a ball mill jar. Use a ball mill to ball mill the mixture, with a ball-to-material ratio of 2:1 and a ball milling speed of 420 r / min. After ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder B3.

[0083] Step 4: Mix powder A3 and powder B3 with ferrous sulfate in a mortar at a mass ratio of 500:1 to obtain powder C3 and powder D3.

[0084] Step 5: Evenly spread 7.55g of powder C3 on both the top and bottom of the low-density C / C.

[0085] Step 6: Continue to evenly spread 2.10g of powder D3 outside the powder laid in step 5, place it above the lower punch of the SPS mold, wrap the low density C / C and powder around the graphite paper, place a Φ30mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press in the upper punch.

[0086] Step 7: Before final heat treatment, the raw materials in the mold from top to bottom are: powder D3 - powder C3 - low density C / C - powder C3 - powder D3. Place the assembled mold in an SPS furnace, set the pressure to 8kN, heat to 1500℃ in a vacuum environment at a heating rate of 450℃ / min, continue heating to 1900℃ at a heating rate of 200℃ / min, hold for 30min, and cool to room temperature at a cooling rate of 200℃ / min before removing.

[0087] Step 8: Use sandpaper to polish and clean the residual graphite paper on the upper and lower surfaces and around the sample to obtain the (Zr, Hf)C-SiC modified C / C composite material with ZrC-HfC-ZrO2-HfO2 multiphase coating.

[0088] See Figure 4 The macroscopic photograph, as shown in Figure (a), shows that the coating is uniformly covering the surface of the composite material without obvious macroscopic defects. The surface XRD pattern, as shown in Figure (b), shows that the coating has a high content of ZrC and HfC, and weak ZrO2 and HfO2. The cross-sectional SEM images, as shown in Figures (c) and (d), show that Figure (c) shows a continuous and dense coating formed on the material surface, with a thickness of ~80µm. The coating has mechanical interlocking with the substrate, and the interface is tightly bonded. Figure (d) is an SEM image of the interior of the substrate, showing a high ceramic content and a dense structure within the substrate.

[0089] Example 4

[0090] Step 1: Use deionized water for ultrasonic cleaning of a sample with dimensions of Φ29mm × 10mm and a density of 1.28g / cm³. 3 The low-density C / C was dried in a far-infrared drying oven at 100℃ for 20 hours.

[0091] Step 2: Mix TaSi2 and TiSi2 in a molar ratio of 1:1 with CaCl2 and KCl in a mass ratio of 6:1 in a ball mill jar and ball mill them with a ball-to-material ratio of 2:1. The ball milling speed is 420 r / min. After ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder A4.

[0092] Step 3: Mix TaSi2 and TiSi2 in a molar ratio of 1:1 with carbon powder and Al2O3 in a molar ratio of 30:10:1 and pour the mixture into a ball mill jar. Use a ball mill to ball mill the mixture. The ball-to-material ratio is 2:1 and the ball milling speed is 420 r / min. After ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder B4.

[0093] Step 4: Mix powder A4 and powder B4 with nickel powder in a mortar at a mass ratio of 300:1 to obtain powder C4 and powder D4.

[0094] Step 5: Evenly spread 7.35g of powder C4 on both the top and bottom of the low-density C / C.

[0095] Step 6: Continue to evenly spread 3.99g of powder D4 outside the powder laid in step 5, place it above the lower punch of the SPS mold, wrap the low density C / C and powder with graphite paper, place Φ30mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press in the upper punch.

[0096] Step 7: Before final heat treatment, the raw materials in the mold from top to bottom are: powder D4 - powder C4 - low density C / C - powder C4 - powder D4. Place the assembled mold in an SPS furnace with a pressure of 7kN. Heat to 1500℃ in a vacuum environment at a heating rate of 450℃ / min, then continue heating to 1650℃ at a heating rate of 200℃ / min. Hold for 120min, then cool to room temperature at a cooling rate of 200℃ / min and remove.

[0097] Step 8: Use sandpaper to polish and clean the residual graphite paper on the upper and lower surfaces and around the sample to obtain the (Ta, Ti)C-SiC modified C / C composite material with TaC-TiC-Ta2O5-TiO2-SiO2 multiphase coating.

[0098] Example 5

[0099] Step 1: Use deionized water for ultrasonic cleaning of a sample with dimensions of Φ29mm × 10mm and a density of 1.28g / cm³. 3 The low-density C / C was dried in a far-infrared drying oven at 100℃ for 15 hours.

[0100] Step 2: Pour TaSi2 and NbSi2 in a molar ratio of 1:1 and CaCl2 and NaCl mixed powder in a mass ratio of 10:1 into a ball mill jar and ball mill them. The ball-to-material ratio is 2:1 and the ball milling speed is 420 r / min. After ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder A5.

[0101] Step 3: Mix TaSi2 and NbSi2 in a molar ratio of 1:1 with carbon powder and Al2O3 in a molar ratio of 35:20:1 and pour the mixture into a ball mill jar. Use a ball mill to ball mill the mixture, with a ball-to-material ratio of 2:1 and a ball milling speed of 420 r / min. After ball milling for 7 hours, place the powder in a far-infrared drying oven at 100℃ and dry it for 12 hours to obtain powder B5.

[0102] Step 4: Mix powder A5 and powder B5 with nickel powder in a mortar at a mass ratio of 300:1 to obtain powder C5 and powder D5.

[0103] Step 5: Evenly spread 7.35g of powder C5 on both the top and bottom of the low-density C / C.

[0104] Step 6: Continue to evenly spread 3.99g of powder D5 outside the powder laid in step 5, place it above the lower punch of the SPS mold, wrap the low density C / C and powder with graphite paper, place Φ30mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press in the upper punch.

[0105] Step 7: Before final heat treatment, the raw materials in the mold are arranged from top to bottom as follows: powder D5 - powder C5 - low density C / C - powder C5 - powder D5. Place the assembled mold in an SPS furnace with a pressure of 7kN. Heat to 1500℃ in a vacuum environment at a heating rate of 450℃ / min, then continue heating to 2100℃ at a heating rate of 200℃ / min. Hold for 30 minutes, then cool to room temperature at a cooling rate of 200℃ / min and remove.

[0106] Step 8: Use sandpaper to polish and clean the residual graphite paper on the upper and lower surfaces and around the sample to obtain the (Ta, Nb)C-SiC modified C / C composite material with TaC-NbC-Ta2O5-NbO2-SiO2 multiphase coating.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an integrated carbon-based composite material with ultra-high temperature ceramic matrix modification and coating, characterized in that, Includes the following steps: S1, lay coating powder in SPS mold, lay melt-infiltrating powder on the coating powder, place low-density C / C composite material on melt-infiltrating powder, lay melt-infiltrating powder on the upper surface of C / C composite material, and lay coating powder on the upper surface of melt-infiltrating powder. The infiltration powder is a mixture of silicide alloy powder, molten salt, and catalyst; the coating powder is a mixture of silicide alloy powder, carbon powder, Al2O3, and catalyst powder. S2, the mold is subjected to pressure and heating heat treatment by SPS, and after cooling, an integrated carbon-based composite material is obtained.

2. The preparation method of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating according to claim 1, characterized in that, In S1, the density of the low-density C / C composite material is 1.1~1.4 g / cm³. 3 .

3. The preparation method of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating according to claim 1, characterized in that, In S1, the silicide alloy powder is one or more of HfSi2, ZrSi2, TiSi2, TaSi2, and NbSi2 powders.

4. The preparation method of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating according to claim 1, characterized in that, In S1, the molten salt is one or more of CaCl2, NaCl, and KCl powder.

5. The method for preparing an integrated carbon-based composite material with modified ultra-high temperature ceramic matrix and coating according to claim 1, characterized in that, In S1, the catalyst is elemental iron or a compound thereof, elemental nickel or a compound thereof.

6. The method for preparing an integrated carbon-based composite material with modified ultra-high temperature ceramic matrix and coating according to claim 1, characterized in that, In S1, during the preparation of the melt-infiltrating powder, silicide alloy powder and molten salt are mixed in a ball mill, a catalyst is added to the mixed powder, and the powder is then ground to obtain the melt-infiltrating powder.

7. The preparation method of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating according to claim 1, characterized in that, In S1, the coating powder is prepared by mixing silicide alloy powder, carbon powder and Al2O3 in a ball mill, adding a catalyst to the mixed powder, and grinding to obtain the coating powder.

8. The preparation method of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating according to claim 1, characterized in that, In S1, the mass ratio of silicide alloy powder to molten salt in the melt-infiltrating powder is 6:1 to 10:

1.

9. The preparation method of an integrated carbon-based composite material for ultra-high temperature ceramic matrix modification and coating according to claim 1, characterized in that, In S1, the molar ratio of the silicide alloy powder, carbon powder, and Al2O3 powder in the coating powder is 30:10:1 to 40:20:

1.

10. The method for preparing an integrated carbon-based composite material with modified ultra-high temperature ceramic matrix and coating according to claim 1, characterized in that, In S2, during the pressurized heating process, the pressure is 6~10kN; the heat treatment temperature is 1500~2100℃; and the holding time is 30~120min.

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