Porous carbon assisted zirconium carbide modified c / c composite material and preparation method thereof

Abstract

This invention discloses a porous carbon-assisted ZrC-modified C / C composite material and its preparation method, belonging to the technical field of ceramic-modified C / C composite materials. The method disclosed in this invention involves sol-gel coagulation, curing, carbonization, and subsequent combination with CVI PyC to obtain a porous carbon matrix with a uniform pore structure and high thermal stability. The porous carbon matrix is ​​then subjected to precursor impregnation-pyrolysis to obtain the porous carbon-assisted ZrC-modified C / C composite material. This method allows for adjustment of the pyrolytic carbon treatment parameters, setting appropriate deposition time and gas flow rate, thereby controlling the skeletal structure of the porous carbon matrix and improving skeletal strength and thermal stability by depositing a pyrolytic carbon coating layer of suitable thickness.

Description

Technical Field

[0001] This invention belongs to the field of ceramic modified C / C composite material technology, specifically relating to a porous carbon-assisted ZrC modified C / C composite material and its preparation method. Background Technology

[0002] Carbon / carbon (C / C) composites possess characteristics such as low density, low coefficient of thermal expansion, high strength, and good thermal shock resistance. Furthermore, their mechanical properties increase with increasing temperature, making them excellent thermal protection candidates that combine structural advantages, lightweight properties, and thermal protection attributes. However, C / C composites begin to oxidize and fail in aerobic environments above 370°C, severely limiting their application in high-temperature oxidizing environments. Therefore, enhancing the ablation resistance of C / C composites is of significant strategic importance. Research indicates that introducing ultra-high temperature ceramics (UHTC) such as carbides and borides is an effective way to improve the oxidation and ablation resistance of C / C composites.

[0003] In ultra-high temperature ceramics, ZrC possesses a high melting point (3540℃), low surface vapor pressure, and good chemical stability, and its oxidation product, ZrO2, exhibits similar properties (melting point 2687℃). Therefore, ZrC is considered an ideal component for UHTC-modified C / C composites. Commonly used methods for modifying ultra-high temperature ceramic matrices include chemical vapor infiltration (CVI), slurry impregnation (SI), reactive infiltration (RMI), and precursor impregnation-pyrolysis (PIP), as well as combinations thereof. Compared to other C / C-UHTCs composite material preparation processes, PIP offers lower preparation temperatures, better material structure designability, near-net-shape molding of large and complex components, and the acquisition of high-purity ceramic matrices.

[0004] Traditional ceramic modification often results in a continuous, plate-like distribution of ceramic components at the macroscopic scale, leading to poor overall thermal control of the composite material. Small-size, homogenized, and dispersed composite ceramic components can be controlled by constructing a three-dimensional porous carbon template. Articles “Journal of the European Ceramic Society, 2020, 40(7):2683-2690” and “Journal of the European Ceramic Society, 2022, 42(4):1219-1226” point out that regulating and modifying the pore structure of preforms based on the principle of pore control is of great significance for improving material preparation and enhancing material properties. Therefore, constructing a three-dimensional porous template with controllable pore size and appropriate porosity is beneficial for achieving a controllable and uniform distribution of the ceramic phase in the composite material.

[0005] Currently, the main methods for preparing carbon matrices include precursor impregnation-pyrolysis (PIP), chemical vapor infiltration (CVI), and sol-gel methods. PIP produces resin carbon in a blocky form, which is prone to cracking during pyrolysis, making it difficult to meet the requirement of component homogeneity. CVI pyrolytic carbon typically has a coated structure, failing to effectively form a structurally controllable framework network and thus not meeting the requirement of structural homogeneity. Sol-gel methods produce porous resin carbon, which can effectively divide large pores, but it is prone to collapse at high temperatures, making it difficult to maintain a porous framework structure. Summary of the Invention

[0006] The purpose of this invention is to provide a porous carbon-assisted ZrC modified C / C composite material and its preparation method, in order to solve the technical problems of easy collapse of porous skeleton and poor overall thermal control capability of composite material in the existing ceramic modification process.

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

[0008] This invention discloses a method for preparing porous carbon-assisted ZrC modified C / C composite materials, comprising the following steps:

[0009] Low-density C / PyC was impregnated in an initial emulsion and then dried to obtain a C / C composite material impregnated with the initial emulsion.

[0010] The C / C composite material impregnated with the initial emulsion was subjected to heating curing, drying and carbonization treatment in sequence to obtain a C / (PyC-PRC) composite material with a porous skeleton.

[0011] A porous carbon matrix was obtained by depositing pyrolytic carbon on a C / (PyC-PRC) composite material containing a porous framework.

[0012] A porous carbon matrix was immersed in an organozirconium polymer solution and subjected to multiple vacuum impregnation-drying processes to obtain a dried composite material. The dried composite material was then heat-treated to obtain a porous carbon-assisted ZrC modified C / C composite material.

[0013] The deposition gas used in the carbon deposition pyrolysis treatment is CH4, with a flow rate of 70–90 L / min; the deposition pyrolysis treatment time is 50–300 min.

[0014] Furthermore, the preparation method of the low-density C / PyC is as follows:

[0015] Pyrolytic carbon was deposited on the fiber preform using the CVI treatment method, yielding a density of 1.0–1.3 g / cm³. 3 Low-density C / PyC.

[0016] Furthermore, the specific steps for depositing pyrolytic carbon on the fiber preform using the CVI treatment method are as follows:

[0017] The fiber preform was placed in a deposition apparatus, and argon was introduced as a protective gas. The deposition apparatus was heated to 900-1100°C at a heating rate of 3-5°C / min. Then, CH4 was introduced to deposit PyC. After deposition, the temperature was cooled to room temperature to obtain low-density C / PyC.

[0018] The argon flow rate during the heating and cooling processes is 1–3 L / min; the argon flow rate during the PyC deposition process is 2–5 L / min, and the CH4 flow rate is 70–90 L / min.

[0019] Furthermore, the method for preparing the initial emulsion is as follows:

[0020] Resorcinol and formaldehyde solution were dissolved in deionized water to obtain a mixture; then hexadecyltrimethylammonium bromide was added to the mixture and stirred to obtain an initial emulsion.

[0021] Further, the ratio of resorcinol, formaldehyde solution, deionized water and hexadecyltrimethylammonium bromide is (10.0-20.0) g: 12.6 g: (14.6-20.0) mL: (0.015-0.24) g;

[0022] The stirring method is magnetic stirring; the magnetic stirring time is 10-20 minutes.

[0023] The formaldehyde solution has a mass concentration of 37 wt.% to 38 wt.%.

[0024] Furthermore, the drying process is a vacuum drying process; the pressure during the vacuum drying process is less than 0.09 MPa, and the vacuum drying time is 20 to 30 minutes.

[0025] Furthermore, the heating curing method is water bath heating curing; the water bath heating curing process is as follows: the C / C composite material impregnated with the initial emulsion is heated in a water bath at 70-90°C for 10-36 hours;

[0026] The drying process is carried out at normal pressure and 80–120°C for 5–8 hours.

[0027] The carbonization process parameters are as follows: under an argon atmosphere, the temperature is increased to 750-1000℃ at a rate of 2-10℃ / min, and held for 2-4 hours.

[0028] Furthermore, the specific process of the deposition pyrolysis carbon treatment is as follows:

[0029] The C / (PyC-PRC) composite material containing a porous framework was placed in a heating device, and argon was used as a protective gas. The heating device was heated to 900-1100℃ at a heating rate of 3-5℃ / min. Then, CH4 was introduced to deposit PyC for 50-300min. After cooling to room temperature, a porous carbon matrix was obtained.

[0030] During the heating and cooling processes, the argon flow rate is 1–3 L / min; during PyC deposition, the argon flow rate is 2–5 L / min.

[0031] Furthermore, the organozirconium polymer solution is obtained by mixing organozirconium polymer and xylene and then magnetically stirring for 1 to 3 hours; the ratio of organozirconium polymer to xylene is (60 to 70) g: (20 to 30) g.

[0032] The vacuum impregnation-drying process is repeated 2 to 3 times.

[0033] The process parameters for the heat treatment are as follows: in an argon atmosphere, the temperature is increased to 1500-1600℃ at a heating rate of 5-10℃ / min, and heated for 2-3 hours.

[0034] The present invention also discloses a porous carbon-assisted ZrC modified C / C composite material prepared by the above preparation method.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] This invention discloses a method for preparing porous carbon-assisted ZrC modified C / C composite materials. The method involves sol-gel coagulation, curing, carbonization, and subsequent combination with CVIPyC to obtain a porous carbon matrix with a uniform pore structure and high thermal stability. The porous carbon matrix is ​​then subjected to precursor impregnation-pyrolysis to obtain the porous carbon-assisted ZrC modified C / C composite material. This method, by adjusting the pyrolytic carbon treatment parameters and setting appropriate deposition time and gas flow rate, can regulate the deposition thickness of the pyrolytic carbon, thereby controlling the skeletal structure of the porous carbon matrix. This improves the skeletal strength and thermal stability by depositing a pyrolytic carbon coating layer of suitable thickness, solving the technical problems of easy collapse of the porous skeleton and poor overall thermal control of the composite material.

[0037] Furthermore, by changing the concentration of the organozirconium polymer solution and the number of impregnation-pyrolysis cycles of the organozirconium polymer solution, the amount of ceramic introduced can be controlled. The segmentation and refinement of the porous carbon matrix skeleton can help the infiltration process of the precursor solution, reduce ceramic agglomeration and blockage, thereby improving the density and ablation performance of the composite material.

[0038] Furthermore, the initial emulsion is obtained by using deionized water as a solvent. It can be effectively impregnated into the pores of the C / PyC preform through vacuum impregnation. The resorcinol-formaldehyde monomer forms a porous framework through in-situ polycondensation, filling the large pores between bundles and layers. This avoids the problem that the resin viscosity is high or that it is difficult to fill the pores of the preform due to gravity and capillary action, thus failing to play the role of dividing and refining the pores.

[0039] Furthermore, in the traditional resorcinol-formaldehyde system, only a surfactant needs to be added, that is, no additional catalyst is required, to form and control the three-dimensional network framework structure; porous carbon with small shrinkage can be prepared by atmospheric pressure drying, and the preparation process has low equipment requirements.

[0040] The present invention also discloses a porous carbon-assisted ZrC modified C / C composite material prepared by the above method. The carbon matrix with a uniform and stable three-dimensional porous skeleton gives it a "hard carbon-soft carbon-ceramic" composite structure. The porous matrix is ​​introduced to replace or partially replace large-sized uneven pores. The carbon matrix and ceramic matrix are evenly distributed, which improves the thermal control capability and ablation resistance of the composite material. Attached Figure Description

[0041] Figure 1 This is a process flow diagram of the preparation method of porous carbon-assisted ZrC modified C / C composite material of the present invention;

[0042] Figure 2 The image shows the morphology of the C / (PyC-PRC) composite material with a porous skeleton obtained in Example 1.

[0043] Where: a-100μm; b-10μm;

[0044] Figure 3 The image shows a SEM image of the porous carbon matrix prepared in Example 1.

[0045] Figure 4 The X-ray diffraction pattern of the porous carbon-assisted ZrC modified C / C composite material prepared in Example 1 is shown below.

[0046] Figure 5 The image shows a cross-section of the porous carbon-assisted ZrC modified C / C composite material prepared in Example 1.

[0047] Where: a-100μm; b-10μm. Detailed Implementation

[0048] 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.

[0049] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0050] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0051] In this article, unless otherwise specified, the terms “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”.

[0052] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0053] like Figure 1 As shown, this invention provides a method for preparing porous carbon-assisted ZrC modified C / C composite material (C / C-ZrC), comprising the following steps:

[0054] Step 1, Preparation of low-density C / PyC:

[0055] Pyrolytic carbon (PyC) was deposited on fiber (Cf) preforms to a semi-densified state using the CVI process, yielding a density of 1.0–1.3 g / cm³. 3 Low-density C / PyC;

[0056] Step 2, Preparation of the initial emulsion:

[0057] Resorcinol (10.0–20.0 g) and 37.5 wt.% formaldehyde solution (12.6 g) were dissolved in deionized water (14.6–20.0 mL) to obtain a mixture; then hexadecyltrimethylammonium bromide (CTAB, 0.015–0.24 g) was added to the mixture, and the suspension was magnetically stirred for 10–20 min to obtain a transparent initial emulsion;

[0058] Step 3, initial emulsion impregnation:

[0059] The low-density C / PyC obtained in step 1 is immersed in the initial emulsion obtained in step 2, so that the block is completely immersed. Then it is placed in a vacuum drying oven and vacuumed until the pressure inside the oven is lower than 0.09 MPa. It is maintained for 20 to 30 minutes to obtain the C / C composite material (C / PyC-R) impregnated with the initial emulsion.

[0060] Step 4, Emulsion curing and carbonization:

[0061] The C / C composite material impregnated with the initial emulsion obtained in step 3 was cured by water bath heating, dried at normal pressure and carbonized at high temperature, so that the resin gel in the composite material was decomposed into carbon, and a C / (PyC-PRC) composite material with a porous skeleton was obtained.

[0062] Step 5, Preparation of the PyC coating layer:

[0063] The C / (PyC-PRC) composite material with a porous framework obtained in step 4 was placed in a CVI furnace. Argon was used as the protective gas, and the equipment was heated to 900-1100°C at a heating rate of 3-5°C / min. Then CH4 was introduced to deposit PyC for 40-300 min. The mixture was then cooled to room temperature to obtain a porous carbon matrix.

[0064] During the heating and cooling process, the argon flow rate was set to 1–3 L / min, and during the deposition process, it was 2–5 L / min. The CH4 flow rate was 70–90 L / min. The deposition time for pyrolytic carbon was 50–300 min.

[0065] Step 6, Precursor Impregnation-Pyrolysis (PIP):

[0066] Organozzirconium polymer (PZC) was added to xylene and magnetically stirred for 1–3 h to obtain a uniform PZC solution (precursor solution). Then, the porous carbon matrix obtained in step 5 was immersed in the precursor solution to completely submerge the bulk material. Vacuum impregnation-drying was performed and repeated 2–3 times. The dried composite material was then placed in a high-temperature furnace for heat treatment. The impregnation-pyrolysis process was repeated multiple times to obtain the C / C-ZrC composite material.

[0067] Preferably, the process of preparing the PyC matrix using the CVI process in step 1 is as follows: Argon gas is introduced as a protective gas, and the equipment is heated to 900-1100°C at a heating rate of 3-5°C / min. Then, CH4 is introduced to deposit PyC, and the temperature is cooled to room temperature. The argon gas flow rate is set to 1-3 L / min during the heating and cooling process, 2-5 L / min during the deposition process, and the CH4 flow rate is 70-90 L / min.

[0068] Preferably, the water bath heating, drying and carbonization process in step 4 is as follows: the C / C composite material impregnated with the initial emulsion obtained in step 3 is heated in a water bath at 70-90°C for 10-36 hours, then dried at 80-120°C under normal pressure for 5-8 hours, and then placed in a tube furnace, heated to 750-1000°C at 2-10°C / min, and held at that temperature for 2-4 hours. Argon gas is introduced throughout the process as a protective gas to decompose the resin gel in the composite material into carbon, thereby obtaining a C / (PyC-PRC) composite material with a porous skeleton.

[0069] Preferably, the heat treatment process for preparing C / C-ZrC composite material in step 6 using the PIP method is as follows: the dried composite material is placed in a high-temperature furnace, argon is introduced as a protective gas, and the equipment is heated to 1500-1600℃ at a heating rate of 5-10℃ / min for 2-3 hours to cause the introduced precursor to decompose and transform into ZrC ceramic.

[0070] The porous carbon-assisted ZrC modified C / C composite material prepared by the method of this invention has advantages such as large specific surface area, high skeleton strength, and high thermal stability. The method of this invention prepares a carbon matrix with a uniform and stable three-dimensional porous skeleton, and in-situ composites the ablation-resistant ceramic component using a precursor impregnation-pyrolysis method. This C / C-ZrC composite material has a "hard carbon-soft carbon-ceramic" composite structure. The introduction of a porous matrix to replace or partially replace large-sized, uneven pores results in a uniform distribution of the carbon matrix and ceramic matrix, improving the composite material's thermal control and ablation resistance.

[0071] 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.

[0072] 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.

[0073] Example 1

[0074] A method for preparing porous carbon-assisted ZrC modified C / C composite material includes the following steps:

[0075] Step 1, Preparation of low-density C / PyC:

[0076] The fiber preform was placed in a deposition apparatus, and argon gas was introduced as a protective gas. The deposition apparatus was heated to 900°C at a heating rate of 3°C / min. Subsequently, CH4 was introduced to perform PyC deposition. After cooling to room temperature, a density of 1.0 g / cm³ was obtained. 3 Low-density C / PyC; wherein the argon flow rate during heating and cooling is set to 1L / min, the deposition process is 2L / min, and the CH4 flow rate is 70L / min;

[0077] Step 2, Preparation of the initial emulsion:

[0078] 10 g and 12.6 g of a 37 wt.% formaldehyde solution were dissolved in 14.6 mL of deionized water to obtain a mixture; then 0.015 g of hexadecyltrimethylammonium bromide was added to the mixture to obtain a suspension; the suspension was magnetically stirred for 10 min to obtain a transparent initial emulsion.

[0079] Step 3, initial emulsion impregnation:

[0080] Low-density C / PyC was immersed in the initial emulsion to completely submerge the bulk material. It was then placed in a vacuum drying oven and evacuated until the pressure inside the oven was below 0.09 MPa. This process was maintained for 20 minutes to obtain a C / C composite material (C / PyC-R) impregnated with the initial emulsion.

[0081] Step 4, Emulsion curing and carbonization:

[0082] The C / C composite material impregnated with the initial emulsion obtained in step 3 was cured by water bath heating, dried at normal pressure and carbonized at high temperature, so that the resin gel in the composite material was decomposed into carbon, and a C / (PyC-PRC) composite material with a porous skeleton was obtained.

[0083] The process of water bath heating curing, atmospheric pressure drying and high temperature carbonization is as follows: the C / C composite material impregnated with the initial emulsion obtained in step 3 is heated in a water bath at 70°C for 10 hours, then dried at atmospheric pressure at 80°C for 5 hours, and then placed in a tube furnace, heated to 750°C at 2°C / min, and held for 2 hours. Argon gas is introduced as a protective gas throughout the process to decompose the resin gel in the composite material into carbon, thereby obtaining a C / (PyC-PRC) composite material with a porous skeleton.

[0084] Step 5, Preparation of the PyC coating layer:

[0085] The C / (PyC-PRC) composite material with a porous framework obtained in step 4 was placed in a CVI furnace. Argon was used as the protective gas, and the equipment was heated to 900°C at a heating rate of 3°C / min. Then CH4 was introduced to deposit PyC (deposit pyrolytic carbon), and then the temperature was cooled to room temperature to obtain a porous carbon matrix.

[0086] During the heating and cooling process, the argon flow rate was set to 1 L / min, and during the deposition process, it was 2 L / min. The CH4 flow rate was 70 L / min, and the deposition time was 50 min.

[0087] Step 6, Precursor Impregnation-Pyrolysis (PIP):

[0088] 60g of organozzirconium polymer (PZC) was added to 20mL of xylene and magnetically stirred for 1h to obtain a uniform PZC solution (precursor solution). Then, the porous carbon matrix obtained in step 5 was immersed in the precursor solution so that the bulk was completely immersed. Vacuum impregnation-drying was performed, and the process was repeated twice. The dried composite material was placed in a high-temperature furnace and heat-treated by the PIP method. The impregnation-pyrolysis process was repeated multiple times to obtain the C / C-ZrC composite material.

[0089] The heat treatment process for preparing C / C-ZrC composite material using the PIP method is as follows: the dried composite material is placed in a high-temperature furnace, argon is introduced as a protective gas, and the equipment is heated to 1500℃ for 2 hours at a heating rate of 5℃ / min, so that the introduced precursor is decomposed and converted into ZrC ceramic.

[0090] Example 2

[0091] A method for preparing porous carbon-assisted ZrC modified C / C composite material includes the following steps:

[0092] Step 1, Preparation of low-density C / PyC:

[0093] The fiber preform was placed in a deposition apparatus, and argon gas was introduced as a protective gas. The deposition apparatus was heated to 1100℃ at a heating rate of 3℃ / min. Subsequently, CH4 was introduced to perform PyC deposition. After cooling to room temperature, a density of 1.3 g / cm³ was obtained.3 Low-density C / PyC; wherein the argon flow rate during heating and cooling is set to 3L / min, the deposition process is 5L / min, and the CH4 flow rate is 90L / min;

[0094] Step 2, Preparation of the initial emulsion:

[0095] 20.0 g and 12.6 g of a 37.5 wt.% formaldehyde solution were dissolved in 20 mL of deionized water to obtain a mixture; then 0.24 g of hexadecyltrimethylammonium bromide was added to the mixture to obtain a suspension; the suspension was magnetically stirred for 20 min to obtain a transparent initial emulsion.

[0096] Step 3, initial emulsion impregnation:

[0097] Low-density C / PyC was immersed in the initial emulsion to completely submerge the bulk material. It was then placed in a vacuum drying oven and evacuated until the pressure inside the oven was below 0.09 MPa. This process was maintained for 30 minutes to obtain a C / C composite material (C / PyC-R) impregnated with the initial emulsion.

[0098] Step 4, Emulsion curing and carbonization:

[0099] The C / C composite material impregnated with the initial emulsion obtained in step 3 was cured by water bath heating, dried at normal pressure and carbonized at high temperature, so that the resin gel in the composite material was decomposed into carbon, and a C / (PyC-PRC) composite material with a porous skeleton was obtained.

[0100] The process of water bath heating curing, atmospheric pressure drying and high temperature carbonization is as follows: the C / C composite material impregnated with the initial emulsion obtained in step 3 is heated in a water bath at 90°C for 36 hours, then dried at atmospheric pressure at 120°C for 8 hours, and then placed in a tube furnace, heated to 1000°C at 10°C / min, and held for 4 hours. Argon gas is introduced as a protective gas throughout the process to decompose the resin gel in the composite material into carbon, thereby obtaining a C / (PyC-PRC) composite material with a porous skeleton.

[0101] Step 5, Preparation of the PyC coating layer:

[0102] The C / (PyC-PRC) composite material with a porous framework obtained in step 4 was placed in a CVI furnace. Argon was used as the protective gas, and the equipment was heated to 1100°C at a heating rate of 5°C / min. Then CH4 was introduced to deposit PyC (deposit pyrolytic carbon), and then the temperature was cooled to room temperature to obtain a porous carbon matrix.

[0103] During the heating and cooling process, the argon flow rate was set to 3 L / min, and during the deposition process, it was 5 L / min. The CH4 flow rate was 90 L / min, and the deposition time was 300 min.

[0104] Step 6, Precursor Impregnation-Pyrolysis (PIP):

[0105] 70g of organozzirconium polymer (PZC) was added to 30mL of xylene and magnetically stirred for 3h to obtain a uniform PZC solution (precursor solution). Then, the porous carbon matrix obtained in step 5 was immersed in the precursor solution so that the bulk was completely immersed. Vacuum impregnation-drying was then performed, and the process was repeated 3 times. The dried composite material was placed in a high-temperature furnace and heat-treated by the PIP method. The impregnation-pyrolysis process was repeated multiple times to obtain the C / C-ZrC composite material.

[0106] The heat treatment process for preparing C / C-ZrC composite material using the PIP method is as follows: the dried composite material is placed in a high-temperature furnace, argon is introduced as a protective gas, and the equipment is heated to 1600℃ for 3 hours at a heating rate of 10℃ / min, so that the introduced precursor is decomposed and transformed into ZrC ceramic.

[0107] Example 3

[0108] A method for preparing porous carbon-assisted ZrC modified C / C composite material includes the following steps:

[0109] Step 1, Preparation of low-density C / PyC:

[0110] The fiber preform was placed in a deposition apparatus, and argon gas was introduced as a protective gas. The deposition apparatus was heated to 1000℃ at a heating rate of 2℃ / min. Subsequently, CH4 was introduced to perform PyC deposition. After cooling to room temperature, a density of 1.1 g / cm³ was obtained. 3 Low-density C / PyC; wherein the argon flow rate during heating and cooling is set to 2L / min, the deposition process is 3L / min, and the CH4 flow rate is 80L / min;

[0111] Step 2, Preparation of the initial emulsion:

[0112] 15 g and 12.6 g of a 37.5 wt.% formaldehyde solution were dissolved in 16 mL of deionized water to obtain a mixture; then 0.08 g of hexadecyltrimethylammonium bromide was added to the mixture to obtain a suspension; the suspension was magnetically stirred for 15 min to obtain a transparent initial emulsion.

[0113] Step 3, initial emulsion impregnation:

[0114] Low-density C / PyC was immersed in the initial emulsion to completely submerge the bulk material. It was then placed in a vacuum drying oven and evacuated until the pressure inside the oven was below 0.09 MPa. This process was maintained for 25 minutes to obtain a C / C composite material (C / PyC-R) impregnated with the initial emulsion.

[0115] Step 4, Emulsion curing and carbonization:

[0116] The C / C composite material impregnated with the initial emulsion obtained in step 3 was cured by water bath heating, dried at normal pressure and carbonized at high temperature, so that the resin gel in the composite material was decomposed into carbon, and a C / (PyC-PRC) composite material with a porous skeleton was obtained.

[0117] The process of water bath heating curing, atmospheric pressure drying and high temperature carbonization is as follows: the C / C composite material impregnated with the initial emulsion obtained in step 3 is heated in a water bath at 80°C for 24 hours, then dried at atmospheric pressure at 100°C for 6 hours, and then placed in a tube furnace, heated to 900°C at 5°C / min, and held for 3 hours. Argon gas is introduced as a protective gas throughout the process to decompose the resin gel in the composite material into carbon, and obtain a C / (PyC-PRC) composite material with a porous skeleton.

[0118] Step 5, Preparation of the PyC coating layer:

[0119] The C / (PyC-PRC) composite material with a porous framework obtained in step 4 was placed in a CVI furnace. Argon was used as the protective gas, and the equipment was heated to 1000°C at a heating rate of 4°C / min. Then CH4 was introduced to deposit PyC (deposit pyrolytic carbon), and then the temperature was cooled to room temperature to obtain a porous carbon matrix.

[0120] During the heating and cooling process, the argon flow rate was set to 2 L / min, and during the deposition process, it was 3 L / min. The CH4 flow rate was 80 L / min, and the deposition time was 100 min.

[0121] Step 6, Precursor Impregnation-Pyrolysis (PIP):

[0122] 60g of organozzirconium polymer (PZC) was added to 25mL of xylene and magnetically stirred for 2h to obtain a uniform PZC solution (precursor solution). Then, the porous carbon matrix obtained in step 5 was immersed in the precursor solution so that the bulk was completely immersed. Vacuum impregnation-drying was performed, and the process was repeated 3 times. The dried composite material was placed in a high-temperature furnace and heat-treated by the PIP method. The impregnation-pyrolysis process was repeated multiple times to obtain the C / C-ZrC composite material.

[0123] The heat treatment process for preparing C / C-ZrC composite material using the PIP method is as follows: the dried composite material is placed in a high-temperature furnace, argon is introduced as a protective gas, and the equipment is heated to 1550℃ for 2 hours at a heating rate of 5℃ / min, so that the introduced precursor is decomposed and converted into ZrC ceramic.

[0124] Example 4

[0125] A method for preparing porous carbon-assisted ZrC modified C / C composite material includes the following steps:

[0126] Step 1, Preparation of low-density C / PyC:

[0127] The fiber preform was placed in a deposition apparatus, and argon gas was introduced as a protective gas. The deposition apparatus was heated to 1000℃ at a heating rate of 2℃ / min. Subsequently, CH4 was introduced to perform PyC deposition. After cooling to room temperature, a density of 1.2 g / cm³ was obtained. 3 Low-density C / PyC; wherein the argon flow rate during heating and cooling is set to 2L / min, the deposition process is 3L / min, and the CH4 flow rate is 80L / min;

[0128] Step 2, Preparation of the initial emulsion:

[0129] 18 g and 12.6 g of a 37.5 wt.% formaldehyde solution were dissolved in 18 mL of deionized water to obtain a mixture; then 0.1 g of hexadecyltrimethylammonium bromide was added to the mixture to obtain a suspension; the suspension was magnetically stirred for 15 min to obtain a transparent initial emulsion.

[0130] Step 3, initial emulsion impregnation:

[0131] Low-density C / PyC was immersed in the initial emulsion to completely submerge the bulk material. It was then placed in a vacuum drying oven and evacuated until the pressure inside the oven was below 0.09 MPa. This process was maintained for 20 minutes to obtain a C / C composite material (C / PyC-R) impregnated with the initial emulsion.

[0132] Step 4, Emulsion curing and carbonization:

[0133] The C / C composite material impregnated with the initial emulsion obtained in step 3 was cured by water bath heating, dried at normal pressure and carbonized at high temperature, so that the resin gel in the composite material was decomposed into carbon, and a C / (PyC-PRC) composite material with a porous skeleton was obtained.

[0134] The process of water bath heating curing, atmospheric pressure drying and high temperature carbonization is as follows: the C / C composite material impregnated with the initial emulsion obtained in step 3 is heated in a water bath at 80°C for 24 hours, then dried at atmospheric pressure at 120°C for 6 hours, and then placed in a tube furnace, heated to 900°C at 5°C / min, and held for 3 hours. Argon gas is introduced as a protective gas throughout the process to decompose the resin gel in the composite material into carbon, thereby obtaining a C / (PyC-PRC) composite material with a porous skeleton.

[0135] Step 5, Preparation of the PyC coating layer:

[0136] The C / (PyC-PRC) composite material with a porous framework obtained in step 4 was placed in a CVI furnace. Argon was used as the protective gas, and the equipment was heated to 1000°C at a heating rate of 4°C / min. Then CH4 was introduced to deposit PyC (deposit pyrolytic carbon), and then the temperature was cooled to room temperature to obtain a porous carbon matrix.

[0137] During the heating and cooling process, the argon flow rate was set to 2 L / min, and during the deposition process, it was 3 L / min. The CH4 flow rate was 80 L / min, and the deposition time was 150 min.

[0138] Step 6, Precursor Impregnation-Pyrolysis (PIP):

[0139] 60g of organozzirconium polymer (PZC) was added to 25mL of xylene and magnetically stirred for 2h to obtain a uniform PZC solution (precursor solution). Then, the porous carbon matrix obtained in step 5 was immersed in the precursor solution so that the bulk was completely submerged. Vacuum impregnation-drying was then performed, and the process was repeated 3 times. The dried composite material was placed in a high-temperature furnace and heat-treated by the PIP method. The impregnation-pyrolysis process was repeated multiple times to obtain the C / C-ZrC composite material.

[0140] The heat treatment process for preparing C / C-ZrC composite material using the PIP method is as follows: the dried composite material is placed in a high-temperature furnace, argon is introduced as a protective gas, and the equipment is heated to 1500℃ for 2 hours at a heating rate of 5℃ / min, so that the introduced precursor is decomposed and converted into ZrC ceramic.

[0141] Example 5

[0142] A method for preparing porous carbon-assisted ZrC modified C / C composite material includes the following steps:

[0143] Step 1, Preparation of low-density C / PyC:

[0144] The fiber preform was placed in a deposition apparatus, and argon gas was introduced as a protective gas. The deposition apparatus was heated to 1000℃ at a heating rate of 2℃ / min. Subsequently, CH4 was introduced to perform PyC deposition. After cooling to room temperature, a density of 1.1 g / cm³ was obtained. 3 Low-density C / PyC; wherein the argon flow rate during heating and cooling is set to 2L / min, the deposition process is 3L / min, and the CH4 flow rate is 80L / min;

[0145] Step 2, Preparation of the initial emulsion:

[0146] 20 g and 12.6 g of a 37.5 wt.% formaldehyde solution were dissolved in 20 mL of deionized water to obtain a mixture; then 0.24 g of hexadecyltrimethylammonium bromide was added to the mixture to obtain a suspension; the suspension was magnetically stirred for 15 min to obtain a transparent initial emulsion.

[0147] Step 3, initial emulsion impregnation:

[0148] Low-density C / PyC was immersed in the initial emulsion to completely submerge the block, and then placed in a vacuum drying oven. The oven was evacuated until the pressure inside was below 0.09 MPa and maintained for 20 minutes to obtain a C / C composite material (C / PyC-R) impregnated with the initial emulsion.

[0149] Step 4, Emulsion curing and carbonization:

[0150] The C / C composite material impregnated with the initial emulsion obtained in step 3 was cured by water bath heating, dried at normal pressure and carbonized at high temperature, so that the resin gel in the composite material was decomposed into carbon, and a C / (PyC-PRC) composite material with a porous skeleton was obtained.

[0151] The process of water bath heating curing, atmospheric pressure drying and high temperature carbonization is as follows: The C / C composite material impregnated with the initial emulsion obtained in step 3 is heated in a water bath at 90°C for 24 hours, then dried at atmospheric pressure at 120°C for 6 hours, and then placed in a tube furnace, heated to 900°C at 5°C / min, and held for 3 hours. Argon gas is introduced as a protective gas throughout the process to decompose the resin gel in the composite material into carbon, thereby obtaining a C / (PyC-PRC) composite material with a porous skeleton.

[0152] Step 5, Preparation of the PyC coating layer:

[0153] The C / (PyC-PRC) composite material with a porous framework obtained in step 4 was placed in a CVI furnace. Argon was used as the protective gas, and the equipment was heated to 1000°C at a heating rate of 4°C / min. Then CH4 was introduced to deposit PyC (deposit pyrolytic carbon), and then the temperature was cooled to room temperature to obtain a porous carbon matrix.

[0154] During the heating and cooling process, the argon flow rate was set to 2 L / min, and during the deposition process, it was 3 L / min. The CH4 flow rate was 80 L / min, and the deposition time was 200 min.

[0155] Step 6, Precursor Impregnation-Pyrolysis (PIP):

[0156] 70g of organozzirconium polymer (PZC) was added to 30mL of xylene and magnetically stirred for 2h to obtain a uniform PZC solution (precursor solution). Then, the porous carbon matrix obtained in step 5 was immersed in the precursor solution so that the bulk was completely immersed. Vacuum impregnation-drying was performed, and the process was repeated 3 times. The dried composite material was placed in a high-temperature furnace and heat-treated by the PIP method. The impregnation-pyrolysis process was repeated multiple times to obtain the C / C-ZrC composite material.

[0157] The heat treatment process for preparing C / C-ZrC composite material using the PIP method is as follows: the dried composite material is placed in a high-temperature furnace, argon is introduced as a protective gas, and the equipment is heated to 1600℃ for 2 hours at a heating rate of 5℃ / min, so that the introduced precursor is decomposed and converted into ZrC ceramic.

[0158] Figure 2 The image shows the morphology of the C / (PyC-PRC) composite material with a porous skeleton obtained in Example 1. Figure 2 It can be seen that a porous carbon skeleton with stacked particles was successfully prepared in low-density C / PyC, and the resin carbon was uniformly distributed in the large pores of the preform, playing a role in segmentation and refinement.

[0159] Figure 3 The image shows a SEM image of the porous carbon matrix prepared in Example 1. Figure 3 It can be seen that pyrolytic carbon (PyC) was successfully deposited on the porous carbon framework, playing a role in coarsening and fixing and protecting it;

[0160] Figure 4 The X-ray diffraction pattern of the porous carbon-assisted ZrC modified C / C composite material prepared in Example 1 is shown below. Figure 4 As can be seen, the XRD shows C peaks and ZrC peaks, proving that the ZrC-modified C / C composite material was successfully prepared.

[0161] Figure 5 This is a SEM image of the cross-section of the porous carbon-assisted ZrC modified C / C composite material prepared in Example 1. Figure 5 It can be seen that the porous carbon matrix after PyC deposition can withstand high-temperature heat treatment and still maintain its unique three-dimensional particle stacking structure, uniformly dividing the ZrC ceramic phase and constructing a "hard carbon-soft carbon-ceramic" composite structure, with the carbon matrix and ceramic matrix being evenly distributed.

[0162] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a porous carbon assisted ZrC modified C / C composite material, characterized in that, Includes the following steps: Low-density C / PyC was impregnated in an initial emulsion and then dried to obtain a C / C composite material impregnated with the initial emulsion. The C / C composite material impregnated with the initial emulsion was subjected to heating curing, drying and carbonization treatment in sequence to obtain a C / (PyC-PRC) composite material with a porous skeleton. A porous carbon matrix was obtained by depositing pyrolytic carbon on a C / (PyC-PRC) composite material containing a porous framework. A porous carbon matrix was immersed in an organozirconium polymer solution and subjected to multiple vacuum impregnation-drying processes to obtain a dried composite material. The dried composite material was then heat-treated to obtain a porous carbon-assisted ZrC modified C / C composite material. The deposition gas used in the carbon deposition pyrolysis treatment is CH4, with a flow rate of 70-90 L / min; the deposition pyrolysis treatment time is 50-300 min. The initial emulsion is prepared by: Resorcinol and formaldehyde solution were dissolved in deionized water to obtain a mixture; then hexadecyltrimethylammonium bromide was added to the mixture and stirred to obtain an initial emulsion; The ratio of resorcinol, formaldehyde solution, deionized water, and hexadecyltrimethylammonium bromide is (10.0~20.0) g : 12.6 g : (14.6~20.0) mL : (0.015~0.24) g; The stirring method is magnetic stirring; the magnetic stirring time is 10-20 minutes. The formaldehyde solution has a mass concentration of 37 wt.% to 38 wt.%.

2. The method for preparing a porous carbon assisted ZrC modified C / C composite material according to claim 1, characterized in that, The preparation method of the low-density C / PyC is as follows: The pyrolytic carbon is deposited on the fiber preform by CVI treatment to obtain low-density C / PyC with a density of 1.0-1.3 g / cm 3 .

3. The method for preparing a porous carbon-assisted ZrC modified C / C composite material according to claim 2, characterized in that, The specific steps for depositing pyrolytic carbon on the fiber preform using the CVI treatment method are as follows: The fiber preform was placed in a deposition apparatus, and argon was introduced as a protective gas. The deposition apparatus was heated to 900-1100 ℃ at a heating rate of 3-5 ℃ / min. Then CH4 was introduced to perform PyC deposition. After deposition, the temperature was cooled to room temperature to obtain low-density C / PyC. The argon flow rate during the heating and cooling processes is 1-3 L / min; the argon flow rate during the PyC deposition process is 2-5 L / min, and the CH4 flow rate is 70-90 L / min.

4. The method for preparing a porous carbon-assisted ZrC modified C / C composite material according to claim 1, characterized in that, The drying process is vacuum drying; the pressure during vacuum drying is below 0.09 MPa, and the drying time is 20-30 minutes.

5. The method for preparing a porous carbon-assisted ZrC modified C / C composite material according to claim 1, characterized in that, The heating curing method is water bath heating curing; the water bath heating curing process is as follows: the C / C composite material impregnated with the initial emulsion is heated in a water bath at 70~90 ℃ for 10~36 h. The drying process is carried out at normal pressure and 80-120°C for 5-8 hours. The carbonization process parameters are as follows: under an argon atmosphere, the temperature is increased to 750-1000 ℃ at a rate of 2-10 ℃ / min, and held for 2-4 h.

6. The method for preparing a porous carbon assisted ZrC modified C / C composite material according to claim 1, characterized in that, The specific process of the deposition pyrolysis carbon treatment is as follows: The C / (PyC-PRC) composite material containing a porous framework was placed in a heating device, and argon was used as a protective gas. The heating device was heated to 900~1100 ℃ at a heating rate of 3~5℃ / min. Then CH4 was introduced to deposit PyC for 50~300 min. After cooling to room temperature, a porous carbon matrix was obtained. During the heating and cooling processes, the argon flow rate is 1~3 L / min; during PyC deposition, the argon flow rate is 2~5 L / min.

7. The method for preparing a porous carbon assisted ZrC modified C / C composite material according to claim 1, characterized in that, The organozirconium polymer solution is obtained by mixing organozirconium polymer and xylene and then magnetically stirring for 1-3 hours; the ratio of organozirconium polymer to xylene is (60-70) g: (20-30) g. The vacuum impregnation-drying process is repeated 2 to 3 times. The process parameters for the heat treatment are as follows: in an argon atmosphere, the temperature is increased to 1500-1600 ℃ at a heating rate of 5-10 ℃ / min, and heated for 2-3 h.

8. A porous carbon assisted ZrC modified C / C composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

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