A high-sintering degree ceramic-based composite material and preparation method thereof

Abstract

The present invention relates to a ceramic-based composite material with a high sintering degree and a preparation method thereof. The method comprises: providing a porous carbon / carbon composite material; uniformly mixing an oxygen-free tantalum carbide ceramic precursor with polytitanium oxane to obtain a tantalum-titanium ceramic precursor; reacting the tantalum-titanium ceramic precursor with the porous carbon / carbon composite material by an impregnation pyrolysis method to obtain a ceramic-based composite material; sintering the ceramic-based composite material under high temperature and high pressure conditions of 1650 to 1850°C and 3.5 to 9.0 MPa to obtain a ceramic-based composite material with a high sintering degree. The present invention gives full play to the uniform distribution of tantalum and titanium components in the ceramic precursor, utilizes the low melting point of titanium oxide, controls the titanium content, and improves the reaction and sintering activity of tantalum carbide, thereby effectively solving the problem of low sintering degree of the ceramic-based composite material.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic-based composite material preparation, and in particular relates to a ceramic-based composite material with a high sintering degree and a preparation method thereof. Background Art

[0002] Carbon fiber reinforced ceramic matrix composites are a new type of composite material with continuous carbon fibers as the toughening phase and high-performance ceramics as the matrix. They have the advantages of high strength and anti-oxidation of ceramics and the toughness of continuous carbon fibers, and are increasingly attracting the attention of scientific and technological workers. At present, the precursor impregnation and cracking technology is a relatively common method for preparing carbon fiber reinforced ceramic matrix composites. However, due to the limitations of precursor structure design, process and performance, they generally face the problems of low degree of ceramic sintering and nano-scale distribution of ceramic particle size, which makes the composite material extremely easy to be washed away by airflow in the use environment, showing poor resistance to ablation and erosion. Therefore, how to further improve the sintering degree of the ceramic matrix of ceramic matrix composites is a key issue for carbon fiber reinforced ceramic matrix composites to have excellent resistance to ablation and erosion in harsh environments such as high temperature and strong airflow.

[0003] In summary, it is very necessary to provide a ceramic-based composite material with a high sintering degree and a preparation method thereof. Summary of the Invention

[0004] In order to solve one or more technical problems existing in the prior art, the present invention provides a ceramic-based composite material with a high sintering degree and a preparation method thereof.

[0005] In a first aspect, the present invention provides a method for preparing a ceramic-based composite material with a high sintering degree, the method comprising the following steps:

[0006] (1) Providing a porous carbon / carbon composite material;

[0007] (2) uniformly mixing the oxygen-free tantalum carbide ceramic precursor and polytitanium oxide to obtain a tantalum-titanium ceramic precursor;

[0008] (3) reacting the tantalum-titanium ceramic precursor with the porous carbon / carbon composite material by an impregnation pyrolysis method to obtain a ceramic-based composite material;

[0009] (4) Sintering the ceramic-based composite material under high temperature and high pressure conditions of 1650-1850° C. and 3.5-9.0 MPa to obtain a ceramic-based composite material with a high sintering degree.

[0010] In a second aspect, the present invention provides a ceramic-based composite material with a high sintering degree, which is prepared by the preparation method described in the first aspect of the present invention.

[0011] Compared with the prior art, the present invention has at least the following beneficial effects:

[0012] (1) The present invention selects a new type of oxygen-free tantalum carbide ceramic precursor and polytitanium oxide to prepare a tantalum-titanium ceramic precursor as reactants, which can effectively avoid the agglomeration of tantalum and titanium, achieve uniform dispersion of the two, and lay the foundation for subsequent high sintering.

[0013] (2) The tantalum-titanium ceramic precursor in the present invention can generate tantalum carbide and titanium oxide during the impregnation and cracking process. The titanium oxide can serve as a sintering activator in the sintering step. Within a suitable temperature range, the titanium oxide forms a semi-liquid state and accelerates the sintering of tantalum carbide, thereby achieving a high sintering degree of the ceramic matrix and obtaining the ceramic-based composite material with a high sintering degree.

[0014] (3) The method of the present invention fully utilizes the uniform distribution of tantalum and titanium components in the tantalum-titanium ceramic precursor, takes advantage of the low melting point of titanium oxide, controls the titanium content, and improves the sintering activity of the tantalum carbide reaction, thereby effectively solving the problem of low sintering degree and poor ablation and erosion resistance of ceramic-based composite materials. The high-sintering degree ceramic-based composite material prepared by the present invention has a ceramic matrix with a high sintering degree, which is manifested as a significant improvement in the ablation and erosion resistance of the ceramic-based composite material.

[0015] (4) In some preferred embodiments of the present invention, the graphene is evenly distributed in the ceramic matrix by laminating and weaving the nickel foam sheet and the carbon cloth, thus avoiding the problem of difficult dispersion and easy agglomeration in the traditional graphene addition method, which can significantly improve the toughness of the ceramic matrix composite material. In addition, the chemical vapor deposition technology is used to prepare a TaC interface layer on the carbon fiber pyrolytic carbon interface layer and the graphene surface using an oxygen-free tantalum carbide ceramic precursor as a reactant. TaC itself has excellent antioxidant and ablation resistance. Compared with the traditional pyrolytic carbon single interface layer, it can improve the antioxidant performance of the composite material. In addition, the traditional method of forming the tantalum carbide interface layer is not suitable for the composite material. The tantalum carbide ceramic precursor is an alkoxy structure and an aerobic system, and its effect on improving the oxidation resistance and high-temperature mechanical properties of ceramic composites needs to be improved; the present invention adopts an oxygen-free tantalum carbide ceramic precursor as a new type of tantalum-based ceramic precursor, which can realize the direct forming of tantalum carbide through chemical vapor deposition technology, and can effectively improve the oxidation resistance and high-temperature mechanical properties of ceramic-based composites. The highly sintered ceramic-based composite material prepared in the preferred technical solution of the present invention has the advantages of high toughness and strong oxidation resistance, which is manifested in significantly improved mechanical properties in a high-temperature aerobic environment and further improved anti-ablation and erosion resistance. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] In a first aspect, the present invention provides a method for preparing a ceramic-based composite material with a high sintering degree, the method comprising the following steps:

[0018] (1) Providing a porous carbon / carbon composite material; in some specific embodiments, the porous carbon / carbon composite material can be prepared, for example, by providing a carbon fiber preform, wherein the density of the carbon fiber preform is, for example, 0.3 to 0.6 g / cm 3 The carbon fiber preform can be, for example, needle-punched, punctured, or stitched; and then a pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain the porous carbon / carbon composite material. The density of the porous carbon / carbon composite material can be, for example, 0.75 to 1.2 g / cm 3 In the present invention, it is preferred that the density of the porous carbon / carbon composite material is 0.75 to 1.2 g / cm 3 , is to effectively regulate the volume proportion of the ceramic matrix component in the subsequent process. If the density of the porous carbon / carbon composite material is too high, the volume proportion of the ceramic matrix component is low, and the ablation resistance of the ceramic matrix composite material obtained may not meet the requirements; if the density of the porous carbon / carbon composite material is too low, the volume proportion of the ceramic matrix component is high, but too much ceramic matrix may also react with the carbon fiber, causing damage to the carbon fiber, and ultimately resulting in poor mechanical properties of the ceramic matrix composite material; and when the density of the porous carbon / carbon composite material is between 0.75 and 1.2 g / cm 3 When the density changes within a certain range, under the same conditions, the lower the density, the higher the volume proportion of the ceramic component in the final ceramic matrix composite material.

[0019] (2) The oxygen-free tantalum carbide ceramic precursor and the polytitanium oxide are mixed evenly to obtain a tantalum-titanium ceramic precursor; in the present invention, for example, the liquid oxygen-free tantalum carbide ceramic precursor and the liquid polytitanium oxide are stirred at a rotation speed of 100 to 400 rpm for 1 to 5 hours to obtain the tantalum-titanium ceramic precursor; the present invention does not specifically limit the source of the polytitanium oxide, and can use products that can be directly purchased or products synthesized by existing methods; in the present invention, the tantalum-titanium ceramic precursor obtained by evenly mixing the oxygen-free tantalum carbide ceramic precursor and the polytitanium oxide is beneficial to avoid the agglomeration of tantalum and titanium, thereby achieving uniform dispersion of the two, laying the foundation for subsequent high sintering.

[0020] (3) The tantalum-titanium ceramic precursor is reacted with the porous carbon / carbon composite material by an impregnation pyrolysis method (impregnation / curing / pyrolysis PIP process) to obtain a ceramic-based composite material; in other words, in the present invention, the tantalum-titanium ceramic precursor is used as a reactant, and a ceramic matrix is prepared by an impregnation pyrolysis technique to obtain a ceramic-based composite material; in some specific embodiments of the present invention, in the impregnation / curing / pyrolysis PIP process, it is preferred that the impregnation is first performed by vacuum impregnation, and the vacuum impregnation pressure is, for example, 20 to 200 Pa, and then The pressure impregnation is performed, the pressure of the pressure impregnation is 1-3 MPa, the time of each vacuum impregnation is 1-2 hours, the time of each pressure impregnation is 1-2 hours, the temperature of the curing is 200-400 ° C, the time of each curing is 2-4 hours, the curing is performed in an argon atmosphere, the temperature of the cracking is 1450-1600 ° C, the time of each cracking is 2-4 hours, the cracking is performed in an argon atmosphere, and the number of times the impregnation, curing and cracking are repeated is not specifically limited in the present invention, until the density of the material reaches 2.5-3.0 g / cm 3 In the present invention, the pressures involved refer to absolute pressures.

[0021] (4) Sintering the ceramic-based composite material under high temperature and high pressure conditions of 1650-1850°C (for example, 1650°C, 1700°C, 1750°C, 1800°C or 1850°C) and 3.5-9.0 MPa (for example, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 or 9 MPa) to obtain a ceramic-based composite material with a high sintering degree; the present invention achieves a high sintering degree of the tantalum carbide ceramic matrix under high temperature and high pressure conditions, and finally obtains the ceramic-based composite material with a high sintering degree; in the present invention, the ceramic-based composite material with a high sintering degree is also referred to as a sintered ceramic-based composite material.

[0022] In step (4) of the present invention, the key point is to limit the sintering reaction pressure to 3.5-9.0 MPa and the temperature to 1650-1850°C. The present invention has found that at high temperature, the oxygen-free tantalum carbide ceramic precursor in the tantalum-titanium ceramic precursor can achieve direct molding of tantalum carbide, while the polytitanium oxide forms titanium oxide because no additional carbon source is introduced into the tantalum-titanium ceramic precursor. Since the formed titanium oxide particles are relatively small, due to the size effect, the formed titanium oxide can form a semi-liquid phase at 1650-1850°C. Under high temperature and high pressure, the semi-liquid phase of titanium oxide diffuses between the tantalum carbide particles to form a sintered bond. Under the action of high gas pressure and capillary force, tantalum carbide particles contact each other and rearrange to form a high packing density. As time goes by, the ceramic matrix eventually reaches a high sintering degree. That is, the tantalum-titanium ceramic precursor in the present invention can generate tantalum carbide and titanium oxide during the impregnation and cracking process. The titanium oxide can be used as a sintering activator in the sintering step. Within a suitable temperature range, the titanium oxide forms a semi-liquid state and accelerates the sintering of tantalum carbide, thereby achieving a high sintering degree of the ceramic matrix and obtaining the high-sintering-degree ceramic-based composite material. In addition, the present invention has found that a moderate sintering reaction pressure of 3.5 to 9.0 MPa can significantly accelerate the sintering degree. ; When the sintering pressure is higher than 9.0MPa, the requirements for high-temperature furnace equipment are too high, and the existing conditions are difficult to meet the needs; and when the sintering pressure is lower than 3.5MPa, the pressure has limited effect on the improvement of the sintering degree and fails to play a good role; in the present invention, the sintering reaction temperature is selected to be 1650-1850℃. When the temperature is higher than 1850℃, the saturated vapor pressure of titanium oxide is relatively high, resulting in its volatilization loss in a short time, and it cannot effectively play the role of a sintering activator (sintering aid); and when the temperature is lower than 1650℃, titanium oxide fails to form a semi-liquid phase state and remains in the form of solid particles, and cannot effectively play the role of a sintering activator. The high-sintering degree ceramic-based composite material prepared by the present invention has a high-sintering degree ceramic matrix, which shows a significant improvement in the ablation and erosion resistance of the high-sintering degree ceramic-based composite material. The linear ablation rate of the high-sintering degree ceramic-based composite material in the oxyacetylene ablation test is less than 1×10 -3 mm / s.

[0023] The method of the present invention fully utilizes the uniform distribution of tantalum and titanium components in the tantalum-titanium ceramic precursor, takes advantage of the low melting point of titanium oxide, controls the titanium content, and improves the reaction sintering activity of tantalum carbide, thereby effectively solving the problem of low sintering degree and poor ablation and erosion resistance of ceramic-based composite materials.

[0024] According to some preferred embodiments, the molar ratio of tantalum contained in the oxygen-free tantalum carbide ceramic precursor to titanium contained in the polytitanium oxide is 10:(0.3-0.8) (e.g., 10:0.3, 10:0.4, 10:0.5, 10:0.6, 10:0.7 or 10:0.8).

[0025] The present invention preferably has a molar ratio of tantalum contained in the oxygen-free tantalum carbide ceramic precursor to titanium contained in the polytitanium oxide of 10: (0.3 ~ 0.8) (i.e., the tantalum-titanium atomic ratio is 10: 0.3-0.8). By controlling the tantalum-titanium atomic ratio to 10: 0.3-0.8, the proportion of tantalum carbide in the ceramic matrix can be increased, and the role of titanium oxide as a sintering activator can be fully utilized. In harsh high-temperature ablation environments, it is necessary to increase the proportion of tantalum carbide as much as possible and appropriately reduce the proportion of titanium oxide, which helps to maximize the material's ablation resistance.

[0026] According to some preferred embodiments, the preparation of the oxygen-free tantalum carbide ceramic precursor is as follows: pentyl (dimethylamino) tantalum or pentyl (diethylamino) tantalum is subjected to an amine exchange reaction with an amine compound, and then subjected to reduced pressure distillation to obtain an oxygen-free tantalum carbide ceramic precursor; the amine compound is one or more of dipropylamine, diisopropylamine, diallylamine (diallylamine), di-n-butylamine, diisobutylamine, di-n-pentylamine, tetrahydropyrrole, and hexahydropyridine; in the present invention, the reduced pressure distillation can remove by-products such as low-boiling-point dimethylamine or diethylamine; in the present invention, the amine exchange reaction is carried out at The method is carried out in an inert gas atmosphere, for example, an argon atmosphere; the molar ratio of the pentadimethylaminotantalum or pentadiethylaminotantalum to the amine compound is 1:(1-5); the temperature of the amine exchange reaction is 100°C to 120°C, and the time is 12 to 18 hours; the present invention uses amino groups as ligands to stabilize the metal center, so that the prepared oxygen-free tantalum carbide ceramic precursor does not contain oxygen, can achieve direct molding of tantalum carbide, is beneficial to reducing the residual oxygen content of the pyrolysis product, and is beneficial to improving the performance of the ceramic-based composite material, and the obtained oxygen-free tantalum carbide ceramic precursor is liquid.

[0027] According to some preferred embodiments, step (4) includes the following sub-steps:

[0028] (a) placing the ceramic matrix composite material obtained in step (3) in a furnace, sealing it and evacuating it, and then introducing an inert gas into the furnace to remove oxygen;

[0029] (b) introducing an inert gas into the furnace body treated in step (a) to a pressure of 3.5 to 9.0 MPa (for example, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 or 9 MPa), and raising the temperature to 1650 to 1850° C. (for example, 1650° C., 1700° C., 1750° C., 1800° C. or 1850° C.) and sintering for 1 to 3 hours (for example, 1, 1.5, 2, 2.5 or 3 hours) to obtain a ceramic-based composite material with a high sintering degree.

[0030] According to some specific embodiments, step (4) is: placing the ceramic-based composite material obtained in step (3) in a high-temperature furnace body, sealing it, evacuating it to a pressure of 20-150 Pa, turning off the vacuum pump, introducing inert gases such as argon and / or nitrogen to normal pressure, and repeating this step at least once to exhaust the air in the high-temperature furnace cavity; introducing inert gases such as argon and / or nitrogen into the high-temperature furnace body to 3.5-9.0 MPa, and heating it to 1650-1750°C, and sintering it at this temperature for 1-3 hours; after the high-temperature and high-pressure sintering reaction is completed, the temperature is controlled by a program at a cooling rate of 1-5°C / min. After cooling to room temperature, the introduction of inert gas is stopped, and the pressure is restored to atmospheric pressure; taking out the sample to obtain a ceramic-based composite material with a high sintering degree; in the present invention, the room temperature is, for example, room temperature of 15-35°C.

[0031] According to some preferred embodiments, the density of the porous carbon / carbon composite material is 0.75 to 1.2 g / cm 3 .

[0032] According to some preferred embodiments, in the impregnation pyrolysis method in step (3), the pyrolysis temperature is 1450-1600°C (e.g., 1450°C, 1500°C, 1550°C or 1600°C); and / or the density of the ceramic matrix composite material obtained in step (3) is 2.5-3.0 g / cm 3 ;

[0033] The present invention can adopt the precursor impregnation cracking technology, use the tantalum titanium ceramic precursor as the reactant, impregnate and crack for many times, and the cracking temperature is 1450-1600 ℃ until the density of 2.5-3.0g / cm is obtained. 3 ceramic matrix composites.

[0034] According to some preferred embodiments, the linear ablation rate of the high sintering degree ceramic matrix composite material in the oxyacetylene ablation test is less than 1×10 -3 mm / s.

[0035] The existing carbon fiber-toughened ceramic-based composite materials have uneven distribution of carbon fibers in the composite materials due to the characteristics of carbon fiber bundles and easy weaving. This makes the ceramic matrix in this area brittle and more prone to through-cracks. In addition, the interface layer of conventional porous carbon / carbon composite materials is usually mainly composed of pyrolytic carbon. Carbon fibers and pyrolytic carbon are both carbon materials, and carbon materials are prone to damage to the structure and performance of carbon fibers in high-temperature oxygen environments. In order to meet the needs of ceramic-based composite materials for use in extreme environments, there is also an urgent need to improve the toughness, mechanical properties and / or antioxidant properties of ceramic-based composite materials.

[0036] According to some preferred embodiments, the porous carbon / carbon composite material is a porous carbon / carbon composite material having a tantalum carbide interface layer, and the preparation of the porous carbon / carbon composite material having a tantalum carbide interface layer comprises the following steps:

[0037] S1. Alternately stacking carbon cloth and nickel foam sheets, and then using a puncture process to form a preform after the alternating stacking; in the present invention, the layers are stacked in the thickness direction, with a layer of nickel foam sheet provided between every two layers of carbon cloth. After the alternating stacking, the preform is woven into a puncture preform through a puncture process; the nickel foam sheet is thin and has a high porosity, and can be used to prepare a preform with the carbon cloth through the puncture process; in the present invention, the nickel foam sheet can be ultrasonically cleaned 1-3 times with ethanol or acetone before use to remove surface impurities; the present invention does not specifically limit the conditions of the puncture process, and conventional puncture processes in the art can be used; in the present invention, the carbon cloth is woven from carbon fibers;

[0038] S2. Depositing pyrolytic carbon and graphene in (inside) the preform by chemical vapor deposition, and then immersing the preform in an acid solution to remove the nickel foam, thereby obtaining a porous carbon / carbon composite material; the acid solution is, for example, one or more of hydrochloric acid, nitric acid solution, and sulfuric acid solution; the concentration of the acid solution is, for example, not greater than 1 mol / L; the immersion temperature is, for example, 25 to 50° C., and the immersion time is, for example, 2 to 5 hours;

[0039] S3, using an oxygen-free tantalum carbide ceramic precursor (also referred to as a polymer oxygen-free tantalum carbide ceramic precursor) as a reactant, depositing a tantalum carbide interface layer in the porous carbon / carbon composite material by chemical vapor deposition to obtain a porous carbon / carbon composite material having a tantalum carbide interface layer; specifically, for example, the porous carbon / carbon composite material with the nickel foam removed is placed in a chemical vapor deposition furnace, and by controlling the heating temperature of the polymer oxygen-free tantalum carbide ceramic precursor, nitrogen, hydrogen and methane are introduced under vacuum and high temperature conditions, and after a certain period of time, a tantalum carbide interface layer is formed on the surface of the continuous carbon fiber and the graphene; the thickness of the tantalum carbide interface layer is, for example, 0.5 to 1.5 μm; in step S3 of the present invention, the oxygen-free The preparation of the tantalum carbide ceramic precursor is also as follows: pentadimethylaminotantalum or pentadiethylaminotantalum is subjected to an amine exchange reaction with an amine compound, and then subjected to reduced pressure distillation to obtain an oxygen-free tantalum carbide ceramic precursor; the amine compound is one or more of di-n-propylamine, diisopropylamine, diallylamine (diallylamine), di-n-butylamine, diisobutylamine, di-n-pentylamine, tetrahydropyrrole, and hexahydropyridine; in the present invention, the amine exchange reaction is carried out in an inert gas atmosphere, for example, in an argon atmosphere; the molar ratio of the pentadimethylaminotantalum or pentadiethylaminotantalum to the amine compound is 1:(1-5); the temperature of the amine exchange reaction is 100°C to 120°C, and the time is 12 to 18 hours.

[0040] When preparing the porous carbon / carbon composite material, the present invention preferably uses nickel foam as a substrate and weaves it with carbon cloth to form a preform, and uses chemical vapor deposition technology to evenly distribute graphene inside the ceramic matrix, thereby avoiding the problems of difficult dispersion and easy agglomeration in traditional graphene addition methods, and can greatly improve the toughness of the ceramic-based composite material. At the same time, the tantalum carbide interface layer can significantly improve the oxidation resistance of the ceramic-based composite material, solving the problems of low toughness and poor oxidation resistance commonly faced by ceramic-based composite materials.

[0041] The present invention preferably adopts chemical vapor deposition technology, uses oxygen-free tantalum carbide ceramic precursor as reactant, and prepares TaC interface layer on the carbon fiber pyrolytic carbon interface layer and the graphene surface. TaC itself has excellent oxidation resistance and ablation resistance, and can improve the oxidation resistance of the composite material compared with the traditional pyrolytic carbon single interface layer; in addition, compared with the traditional method of forming tantalum carbide interface layer, the present invention adopts oxygen-free tantalum carbide ceramic precursor as a new type of tantalum-based ceramic precursor, which can realize direct forming of tantalum carbide, and can effectively improve the oxidation resistance and high-temperature mechanical properties of ceramic-based composite materials. The present invention preferably uses the porous carbon / carbon composite material with a tantalum carbide interface layer obtained by steps S1 to S3 to prepare the said high-sintering degree ceramic-based composite material. The prepared said high-sintering degree ceramic-based composite material has the advantages of high toughness and strong oxidation resistance, which is manifested as significantly improved mechanical properties in a high-temperature aerobic environment and further improved ablation and erosion resistance.

[0042] According to some preferred embodiments, the thickness of the nickel foam sheet is 0.02 to 0.08 mm (e.g., 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 mm), and / or the surface density of the nickel foam sheet is 150 to 370 g / m 2 (e.g. 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360 or 370 g / m 2 ); In the present invention, the thickness of the nickel foam sheet is preferably 0.02 to 0.08 mm. The present invention finds that controlling the thickness of the nickel foam sheet is very critical. If the thickness is higher than 0.08 mm, the pores will be too large after the acid solution is removed, affecting the mechanical properties of the composite material; and if the thickness is lower than 0.02 mm, the subsequent graphene content will be low, and the composite material cannot be toughened well; In the present invention, the thickness of the nickel foam sheet is 0.02 to 0.08 mm, which can also be recorded as an ultra-thin nickel foam sheet.

[0043] According to some preferred embodiments, in step S1, in the preform, the volume proportion of the nickel foam sheet is 5% to 20% (for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%). In other words, in the preform, the volume proportion of the nickel foam sheet is 5%-20%. The present invention does not specifically limit the number of layers of the alternately stacked carbon cloth and the nickel foam sheet, so that in the preform, the nickel foam sheet The volume proportion of the nickel foam sheet can be 5 to 20%. In the present invention, preferably, in the preform, the volume proportion of the nickel foam sheet is 5 to 20%. The present invention finds that by controlling the volume proportion of the nickel foam sheet, the mechanical properties of the ceramic-based composite material can be effectively regulated. When the volume proportion of the nickel foam sheet is higher than 20%, the pores will be too large after the acid solution is removed, affecting the mechanical properties of the composite material. When the volume proportion of the nickel foam sheet is lower than 5%, the subsequent graphene content is low, and the composite material cannot be well toughened.

[0044] According to some preferred embodiments, in step S2: the deposition is carried out in an atmosphere comprising nitrogen, hydrogen and methane, and the volume flow ratio of the nitrogen, hydrogen and methane is 10:3:(2-5) (for example, 10:3:2, 10:3:2.5, 10:3:3, 10:3:3.5, 10:3:4, 10:3:4.5 or 10:3:5); and / or the deposition temperature is 800-1000°C (for example, 800°C, 850°C, 900°C, 950°C or 1000°C), and the deposition time is 0.5-2h (for example, 0.5, 1, 1.5 or 2h).

[0045] The present invention has found that when depositing pyrolytic carbon and graphene inside the preform, the key is to control the flow ratio of nitrogen, hydrogen and methane, that is, the deposition is carried out in step S2. Preferably, the volume flow ratio of nitrogen, hydrogen and methane is 10:3:(2-5), which is conducive to ensuring that the ceramic-based composite material with high toughness and strong antioxidant properties is obtained, and the mechanical properties of the obtained ceramic-based composite material in a high-temperature oxygen environment are significantly improved. Although there are reports on growing a pyrolytic carbon interface layer on the surface of carbon fiber or growing graphene on the surface of nickel foam, it is relatively difficult to achieve uniform preparation of pyrolytic carbon and graphene in the same cavity and the same sample, and no prior art has been found to involve this. This is because the deposition of methane on the surface of carbon fiber is a non-catalytic growth, while on the surface of nickel foam it is a metal-catalyzed growth, and the growth mechanisms of the two are quite different. The present invention creatively achieves good pyrolytic carbon and graphene growth effects simultaneously by finely regulating the flow ratio of nitrogen, hydrogen and methane at 10:3:(2-5); the present invention finds that if the flow ratio of the three is lower than 10:3:2, graphene growth on the surface of nickel foam will be good while the deposition effect of pyrolytic carbon on the surface of carbon fiber will be poor; if the flow ratio of the three is higher than 10:3:5, amorphous carbon rather than graphene will be more easily formed on the surface of nickel foam.

[0046] According to some preferred embodiments, in step S3: the oxygen-free tantalum carbide ceramic precursor is heated and then introduced into a chemical vapor deposition furnace through a carrier gas nitrogen, and at the same time, hydrogen and methane are introduced into the chemical vapor deposition furnace to deposit the tantalum carbide interface layer; wherein the volume flow ratio of nitrogen, hydrogen and methane is 10:6:(4-10) (for example, 10:6:4, 10:6:5, 10:6:6, 10:6:7, 10:6:8, 10:6:9 or 10:6:10).

[0047] According to some preferred embodiments, the heating temperature of the oxygen-free tantalum carbide ceramic precursor is 80-100°C (e.g., 80°C, 90°C, or 100°C); the temperature for depositing the tantalum carbide interface layer is 1020-1550°C (e.g., 1020°C, 1050°C, 1080°C, 1100°C, 1120°C, 1150°C, 1180°C, 1200°C, 1250°C, 1300°C, 1350°C, 0°C, 1400°C, 1450°C, 1500°C or 1550°C), the time is 0.5-2h (for example, 0.5, 1, 1.5 or 2h), the pressure in the chemical vapor deposition furnace is 20-200Pa (for example, 20, 50, 80, 100, 120, 150, 180 or 200Pa); in some preferred embodiments, the temperature for depositing the tantalum carbide interface layer is 1020-1180°C.

[0048] The present invention has found through a large number of creative experiments that when a tantalum carbide ceramic precursor is used as a reactant and a tantalum carbide interface layer is deposited in the porous carbon / carbon composite material by chemical vapor deposition, it is preferred to control the chemical vapor deposition temperature in the reactor to 1020-1550°C and adjust the flow ratio of nitrogen, hydrogen and methane to 10:6:(4-10). In this way, a ceramic-based composite material with strong antioxidant properties and significantly improved mechanical properties in a high-temperature aerobic environment can be obtained; the present invention has found that if the chemical vapor deposition temperature is too high, the oxygen-free tantalum carbide ceramic precursor will be thermally decomposed. If the rate is too fast, amorphous carbon and other substances may be formed, resulting in a decrease in the oxidation resistance of the ceramic-based composite material. If the chemical vapor deposition temperature is lower than 1020°C, the oxygen-free tantalum carbide ceramic precursor will not be fully cracked, and a stable TaC interface layer will not be formed, which will also lead to a decrease in the oxidation resistance of the ceramic-based composite material. If the flow ratio of nitrogen, hydrogen and methane is higher than 10:6:10, excessive methane will more easily form amorphous carbon, resulting in a decrease in the oxidation resistance of the material. If it is lower than 10:6:4, the methane supply is insufficient, which can easily lead to poor TaC crystal shape, also affecting its oxidation resistance.

[0049] In a second aspect, the present invention provides a ceramic-based composite material with a high sintering degree, which is prepared by the preparation method described in the first aspect of the present invention.

[0050] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments. The present invention may also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention. Unless otherwise specified, the experimental methods used in the following examples are all conventional methods. The materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels or prepared by existing methods.

[0051] The preparation of the oxygen-free tantalum carbide ceramic precursor involved in the following embodiments and comparative examples of the present invention is as follows:

[0052] The three-necked flask was repeatedly evacuated and filled with argon to replace the air, and penta(dimethylamino)tantalum was added, followed by diallylamine. The mixture was stirred and reacted at 105°C in an argon atmosphere for 15 hours. The reactants were then distilled under reduced pressure to obtain a liquid oxygen-free tantalum carbide ceramic precursor; wherein the molar ratio of penta(dimethylamino)tantalum to diallylamine was 1:1.

[0053] Example 1

[0054] ① Providing a porous carbon / carbon composite material: providing a punctured carbon fiber preform, wherein the density of the punctured carbon fiber preform is 0.5 g / cm3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the punctured carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.8 g / cm 3 .

[0055] ② Preparation of tantalum-titanium ceramic precursor: The liquid oxygen-free tantalum carbide ceramic precursor and the liquid polytitanium oxide are stirred at a rotation speed of 150 rpm for 4 hours to mix uniformly to obtain a tantalum-titanium ceramic precursor; wherein the amount of the oxygen-free tantalum carbide ceramic precursor and the polytitanium oxide is such that the molar ratio of tantalum contained in the oxygen-free tantalum carbide ceramic precursor to titanium contained in the polytitanium oxide is 10:0.4 (abbreviated as the tantalum-titanium atomic ratio is 10:0.4).

[0056] ③ Preparation of ceramic matrix composites: Using the tantalum-titanium ceramic precursor prepared in step ② as the reactant, the porous carbon / carbon composite material obtained in step ① was subjected to multiple impregnation, curing and pyrolysis by the impregnation / curing / pyrolysis PIP process until a density of 2.8 g / cm was obtained. 3 Ceramic-based composite materials; in each impregnation / curing / cracking round, the impregnation is first performed by vacuum impregnation, the vacuum impregnation pressure is 200 Pa, and then pressure impregnation is performed, the pressure of pressure impregnation is 1.5 MPa, the time of each vacuum impregnation is 1 hour, the time of each pressure impregnation is 1 hour, the curing temperature is 250°C, the time of each curing is 2 hours, the curing is carried out in an argon atmosphere, the cracking temperature is 1500°C, the time of each cracking is 2 hours, and the cracking is carried out in an argon atmosphere.

[0057] ④ Ceramic matrix sintering reaction: Place the ceramic matrix composite material obtained in step ③ in a high-temperature furnace body, seal it, evacuate it to a pressure of 30 Pa, turn off the vacuum pump, introduce argon to normal pressure, and repeat this step at least once to exhaust the air in the cavity; then, introduce argon into the high-temperature furnace body to 5.0 MPa, raise the temperature to 1700°C, and sinter at this temperature for 2 hours; after the above-mentioned high-temperature and high-pressure reaction is completed, cool it down by program control at a cooling rate of 3°C / min. After cooling to room temperature, stop introducing argon and return it to atmospheric pressure; then remove the sample to obtain a ceramic matrix composite material with a high sintering degree.

[0058] Ablation and erosion resistance test: The linear ablation rate of the high sintering degree ceramic matrix composite material obtained in this embodiment under oxyacetylene ablation environment was 0.6×10 -3 mm / s; it should be noted that the oxyacetylene test conditions for measuring the linear ablation rate of the present invention are: oxygen and acetylene pressures are 0.6 MPa and 0.1 MPa respectively, oxygen and acetylene flow rates are 1500 L / h and 900 L / h respectively, the ablation distance is 30 mm, and the ablation time is 100 s.

[0059] Mechanical property test under high temperature oxygen environment: The high sintering degree ceramic matrix composite material prepared in this embodiment was measured to have a flexural strength of 181 MPa under 1500° C. air environment.

[0060] Examples 2 to 9

[0061] The specific process parameters of Examples 2 to 9 and the performance indicators of the finally obtained sintered ceramic matrix composite materials are shown in Table 1. The other preparation processes are the same as those of Example 1.

[0062]

[0063] As shown in Table 1, compared with Example 1, when preparing the tantalum-titanium ceramic precursor in Example 2, the tantalum-titanium atomic ratio is changed from 10:0.4 to 10:0.7, and more titanium oxide can participate in sintering, so that the sintering degree of the ceramic matrix is higher, and finally the linear ablation rate of the high-sintering degree ceramic matrix composite material in the oxyacetylene ablation environment is increased from 0.6×10 -3 mm / s is reduced to 0.45×10- 3 Compared with Example 1, in Example 3, when preparing the tantalum-titanium ceramic precursor, the atomic ratio of tantalum and titanium was changed from 10:0.4 to 10:0.2, and the amount of titanium oxide that could participate in sintering was less, resulting in an insignificant improvement in the sintering degree of the ceramic matrix. Ultimately, the linear ablation rate of the sintered ceramic matrix composite material in the oxyacetylene ablation environment was reduced from 0.6×10 -3 mm / s increased to 3.9×10 -3 Compared with Example 1, when preparing the tantalum-titanium ceramic precursor in Example 4, the tantalum-titanium atomic ratio was changed from 10:0.4 to 10:1.2. Although more titanium oxide can participate in sintering, making the ceramic matrix sintered to a higher degree, the volume proportion of titanium oxide is also higher, which ultimately leads to the linear ablation rate of the ceramic matrix composite material in the oxyacetylene ablation environment being reduced from 0.6×10 -3 mm / s increased to 1.1×10 -3 Compared with Example 1, in Example 5, the high-temperature furnace chamber sintering pressure was set from 5.0 MPa to 2.5 MPa, which reduced the sintering degree of the ceramic matrix. As a result, the linear ablation rate of the sintered ceramic matrix composite material in the oxyacetylene ablation environment decreased from 0.6×10 -3 mm / s increased to 3.2×10 -3 Compared with Example 1, when setting the high-temperature furnace chamber sintering pressure in Example 6, the pressure was increased from 5.0 MPa to 8.0 MPa, which improved the sintering degree of the ceramic matrix. Finally, the linear ablation rate of the high-sintering degree ceramic matrix composite material in the oxyacetylene ablation environment was reduced from 0.6×10 -3 mm / s decreased to 0.37×10 -3 Compared with Example 1, when the high-temperature furnace chamber sintering temperature of Example 7 was set to 1500°C, it was impossible to make titanium oxide form a semi-liquid phase, which significantly reduced the sintering degree of the ceramic matrix. As a result, the linear ablation rate of the sintered ceramic matrix composite material in the oxyacetylene ablation environment decreased from 0.6×10 -3 mm / s increased to 4.2×10 -3 Compared with Example 1, in Example 8, the high-temperature furnace chamber sintering temperature was increased from 1700°C to 1800°C, which significantly improved the sintering degree of the ceramic matrix. Finally, the linear ablation rate of the high-sintering degree ceramic matrix composite material in the oxyacetylene ablation environment was reduced from 0.6×10 -3 mm / s is reduced to 0.41×10 -3 mm / s. Compared with Example 1, when the high-temperature furnace chamber sintering temperature of Example 9 was set to 2000°C from 1700°C, the saturated vapor pressure of titanium oxide was higher, resulting in its volatilization loss in a short time, which affected the sintering degree of the ceramic matrix to a certain extent, and ultimately caused the linear ablation rate of the sintered ceramic matrix composite material in the oxyacetylene ablation environment to decrease from 0.6×10 -3 mm / s increased to 1.3×10 -3 mm / s.

[0064] Example 10

[0065] ① Nickel foam sheet: The thickness of the nickel foam sheet is 0.05mm and the surface density is 350g / m 2 , ultrasonically cleaned with ethanol twice to remove surface impurities.

[0066] ② Preform weaving: The nickel foam sheet and carbon cloth are stacked and arranged, and the preform is weaved into a preform by a puncture process, so that the volume ratio of the nickel foam sheet is 12%; the density of the obtained preform is 1.05g / cm 3 .

[0067] ③ Preparation of porous carbon / carbon composite materials: Place the above-mentioned preform in the cavity of a chemical vapor deposition furnace, evacuate to 80 Pa, remove the air in the cavity, and then continuously fill the cavity with nitrogen and hydrogen. The temperature is raised to a reaction temperature of 1000°C at a heating rate of 6°C / min. At this time, methane is introduced, and the volume flow ratio of nitrogen, hydrogen and methane is controlled at 10:3:4. The reaction time is 1 hour. After the reaction is completed, heating is stopped, and nitrogen is continued to be introduced until the cavity temperature drops to room temperature. The sample is taken out and then immersed in 0.5 mol / L hydrochloric acid solution, soaked at 50°C for 3 hours, and then placed in distilled water for washing. The hydrochloric acid solution immersion and distilled water washing are repeated several times to ensure that the foam nickel is completely removed. Dry and obtain a porous carbon / carbon composite material.

[0068] ④ Preparation of a porous carbon / carbon composite material with a tantalum carbide interface layer: The porous carbon / carbon composite material obtained in step ③ is placed in a chemical vapor deposition reactor (reactor), vacuum is drawn, the pressure in the reactor is 150Pa, and the temperature in the reactor is controlled at 1100℃ and kept warm for 10 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated oxygen-free tantalum carbide ceramic precursor is brought into the chemical vapor deposition reactor chamber by nitrogen as a carrier gas. The heating temperature of the oxygen-free tantalum carbide ceramic precursor is controlled at 95℃. While maintaining the carrier gas nitrogen continuously carrying the oxygen-free tantalum carbide ceramic precursor into the chamber, hydrogen and methane are introduced into the furnace chamber. The volume flow ratio of nitrogen, hydrogen and methane is 10:6:6, of which the nitrogen flow rate is controlled at 2L / min. After the reactor is kept at 1100℃ for 2 hours, a tantalum carbide interface layer (TaC interface layer) with a thickness of 1.5μm is formed on the surface of the carbon fiber and graphene. The temperature is then lowered, and the heating of the oxygen-free tantalum carbide ceramic precursor and the introduction of methane and hydrogen are stopped in turn. Nitrogen is kept introduced throughout the cooling process until the temperature drops to room temperature. The sample is taken out to obtain a porous carbon / carbon composite material with a tantalum carbide interface layer.

[0069] ⑤ Preparation of tantalum-titanium ceramic precursor: The liquid oxygen-free tantalum carbide ceramic precursor and the liquid polytitanium oxide are stirred at a rotation speed of 150 rpm for 4 hours to mix evenly to obtain a tantalum-titanium ceramic precursor; wherein, the amount of the oxygen-free tantalum carbide ceramic precursor and the polytitanium oxide is such that the molar ratio of tantalum contained in the oxygen-free tantalum carbide ceramic precursor to titanium contained in the polytitanium oxide is 10:0.4 (abbreviated as the tantalum-titanium atomic ratio is 10:0.4).

[0070] ⑥ Preparation of ceramic matrix composite material: Using the tantalum-titanium ceramic precursor prepared in step ⑤ as the reactant, the porous carbon / carbon composite material with a tantalum carbide interface layer obtained in step ④ was subjected to multiple impregnation, curing and pyrolysis by the impregnation / curing / pyrolysis PIP process until a density of 2.8 g / cm was obtained. 3 Ceramic-based composite materials; in each impregnation / curing / cracking round, the impregnation is first performed by vacuum impregnation, the vacuum impregnation pressure is 200 Pa, and then pressure impregnation is performed, the pressure of pressure impregnation is 1.5 MPa, the time of each vacuum impregnation is 1 hour, the time of each pressure impregnation is 1 hour, the curing temperature is 250°C, the time of each curing is 2 hours, the curing is carried out in an argon atmosphere, the cracking temperature is 1500°C, the time of each cracking is 2 hours, and the cracking is carried out in an argon atmosphere.

[0071] ⑦ Ceramic matrix sintering reaction: Place the ceramic matrix composite material obtained in step ⑥ in a high-temperature furnace body, seal it, evacuate it to a pressure of 30 Pa, turn off the vacuum pump, introduce argon to normal pressure, and repeat this step at least once to exhaust the air in the cavity; then, introduce argon into the high-temperature furnace body to 5.0 MPa, raise the temperature to 1700°C, and sinter at this temperature for 2 hours; after the above-mentioned high-temperature and high-pressure reaction is completed, cool it down by program control at a cooling rate of 3°C / min. After cooling to room temperature, stop introducing argon and return it to atmospheric pressure; then remove the sample to obtain a ceramic matrix composite material with a high sintering degree.

[0072] Mechanical property test under high temperature oxygen environment: The high sintering degree ceramic matrix composite material prepared in this embodiment was measured to have a flexural strength of 346 MPa under 1500° C. air environment.

[0073] Ablation and erosion resistance test: The linear ablation rate of the high sintering degree ceramic matrix composite material obtained in this embodiment under oxyacetylene ablation environment was measured to be 0.18×10 -3 mm / s.

[0074] Examples 11 to 14

[0075] Examples 11 to 14 are substantially the same as Example 10, with the differences being shown in Table 2.

[0076] Table 2

[0077]

[0078] As can be seen from Table 2, compared with Example 10, when the deposition temperature of the oxygen-free tantalum carbide ceramic precursor is selected in Example 11, the deposition temperature is reduced from 1100°C to 950°C, resulting in insufficient decomposition of the precursor and poor TaC deposition effect. The resulting high-sintering degree ceramic matrix composite material has poor oxidation resistance, and the flexural strength in an air environment of 1500°C is reduced from 346 MPa to 229 MPa. Compared with Example 10, when the deposition temperature of the oxygen-free tantalum carbide ceramic precursor is selected in Example 12, the deposition temperature is increased from 1100°C to 1700°C. The thermal decomposition rate is too fast, and substances such as amorphous carbon may be formed, resulting in a decrease in the material's oxidation resistance. The flexural strength in an air environment of 1500°C is reduced from 346 MPa to 251 MPa. Compared to Example 10, in Example 13, when depositing the TaC interface layer, the flow ratio of nitrogen, hydrogen, and methane was reduced from 10:6:6 to 10:6:2. Insufficient methane supply easily leads to poor TaC crystallinity, affecting the oxidation resistance of the high-sintering degree ceramic-based composite material. The flexural strength in an air environment at 1500°C was reduced from 346 MPa to 238 MPa. Compared to Example 10, in Example 14, when depositing the TaC interface layer, the flow ratio of nitrogen, hydrogen, and methane was increased from 10:6:6 to 10:6:12. Excessive methane is more likely to form amorphous carbon, which also leads to poor oxidation resistance of the high-sintering degree ceramic-based composite material. The flexural strength in an air environment at 1500°C was reduced from 346 MPa to 196 MPa.

[0079] Example 15

[0080] ① is the same as step ① of Example 10.

[0081] ② is the same as step ② of Example 10.

[0082] ③ is the same as step ③ of Example 10.

[0083] ④ Preparation of a porous carbon / carbon composite material with a tantalum carbide interface layer: soak the porous carbon / carbon composite material obtained in step ③ in a nitric acid solution with a concentration of 6 mol / L and keep it at 80 ° C for 150 min, and then dry it in an oven at 80 ° C for 240 min to obtain a modified porous carbon / carbon composite material; prepare a Ta(NO3)4 aqueous solution with a concentration of 0.1 mol / L, soak the obtained modified porous carbon / carbon composite material in a Ta(NO3)4 aqueous solution and pressurize it for 240 min at a pressure of 0.3 MPa, dry it in an oven at 80 ° C for 240 min, and then place it in a sintering device and heat it to 600 ° C ( The method comprises the following steps: heating the porous carbon / carbon composite material to a temperature of 600°C for 120 minutes, cooling the porous carbon / carbon composite material to a temperature of 1.5 μm and heating the porous carbon / carbon composite material to a temperature of 1600°C for 120 minutes at a heating rate of 5°C / min, maintaining the temperature at 600°C for 120 minutes, cooling the porous carbon / carbon composite material to a temperature of 5°C / min and obtaining a porous carbon / carbon composite material having a tantalum oxide layer with a thickness of 1.5 μm; placing the porous carbon / carbon composite material having a tantalum oxide layer with a thickness of 1.5 μm in a high-temperature device, heating the porous carbon / carbon composite material to a temperature of 1600°C under the protection of inert gas argon (heating rate of 5°C / min), maintaining the temperature at 1600°C for 120 minutes, causing a carbon thermal reduction reaction to convert the tantalum oxide layer into a tantalum carbide layer, and cooling the porous carbon / carbon composite material to a tantalum carbide layer with a thickness of 1.5 μm.

[0084] ⑤ The same as step ⑤ of Example 10.

[0085] ⑥ is the same as step ⑥ of Example 10.

[0086] ⑦ Same as step ⑦ of Example 10.

[0087] Mechanical property test under high temperature oxygen environment: The high sintering degree ceramic matrix composite material prepared in this embodiment was measured to have a flexural strength of 211 MPa under 1500° C. air environment.

[0088] Ablation and erosion resistance test: The linear ablation rate of the high sintering degree ceramic matrix composite material obtained in this embodiment under oxyacetylene ablation environment was measured to be 0.42×10 -3 mm / s.

[0089] Comparative Example 1

[0090] ① Providing a porous carbon / carbon composite material: providing a punctured carbon fiber preform, wherein the density of the punctured carbon fiber preform is 0.5 g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the punctured carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.8 g / cm 3 .

[0091] ② Preparation of tantalum silicon ceramic precursor: stirring polytantalum oxane, polycarbosilane and xylene at a rotation speed of 150 rpm for 3 hours to achieve uniform mixing of polytantalum oxane and polycarbosilane, then adding phenolic resin at a rotation speed of 150 rpm and stirring at 130°C for 10 hours to obtain a tantalum silicon ceramic precursor; wherein, the amount of polytantalum oxane and polycarbosilane is such that the molar ratio of tantalum contained in polytantalum oxane to silicon contained in polycarbosilane is 5:1, the mass ratio of the sum of the amounts of polytantalum oxane and polycarbosilane to the amount of xylene solvent is 10:1, and the mass ratio of the sum of the amounts of polytantalum oxane and polycarbosilane to the amount of phenolic resin is 10:1.

[0092] ③ Preparation of ceramic matrix composite materials: the density of 0.8g / cm 3 The porous carbon / carbon composite material is placed in the tantalum silicon ceramic precursor prepared in step ②, and the tantalum silicon ceramic precursor is fully impregnated into the pores inside the porous carbon / carbon composite material by vacuum impregnation + pressure impregnation. The pressure of vacuum impregnation is 200 Pa, and the time of each vacuum impregnation is 1 hour. The pressure of pressure impregnation is 1.5 MPa, and the time of each pressure impregnation is 1 hour. The porous carbon / carbon composite material impregnated with the tantalum silicon ceramic precursor is placed in a reaction furnace body, sealed, and evacuated. The absolute pressure in the reaction furnace body is 1 Pa, and inert gas argon is introduced with an argon flow rate of 100 sccm. The temperature is set to be controlled by a program at a heating rate of 10°C / min, raised to 200°C for curing for 120 minutes, then raised to 1500°C, and cracked under vacuum conditions for 120 minutes. After the reaction, the temperature is controlled by a program at a cooling rate of 50°C / min, cooled to room temperature, the inert gas is turned off, and the temperature is restored to atmospheric pressure, and the sample is taken out. Repeat the above impregnation, curing and cracking process until the density of the ceramic matrix composite material reaches 3.6g / cm 3 .

[0093] The ablation and erosion resistance test: The linear ablation rate of the ceramic matrix composite material obtained in this comparative example under oxyacetylene ablation environment was 6.5×10 -3 mm / s.

[0094] Comparative Example 2

[0095] ① Providing a porous carbon / carbon composite material: providing a punctured carbon fiber preform, wherein the density of the punctured carbon fiber preform is 0.5 g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the punctured carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.8 g / cm 3 .

[0096] ② Preparation of tantalum silicon ceramic precursor: stirring polytantalum oxane, polycarbosilane and xylene at a rotation speed of 150 rpm for 3 hours to achieve uniform mixing of polytantalum oxane and polycarbosilane, then adding phenolic resin at a rotation speed of 150 rpm and stirring at 130°C for 10 hours to obtain a tantalum silicon ceramic precursor; wherein, the amount of polytantalum oxane and polycarbosilane is such that the molar ratio of tantalum contained in polytantalum oxane to silicon contained in polycarbosilane is 5:1, the mass ratio of the sum of the amounts of polytantalum oxane and polycarbosilane to the amount of xylene solvent is 10:1, and the mass ratio of the sum of the amounts of polytantalum oxane and polycarbosilane to the amount of phenolic resin is 10:1.

[0097] ③ Preparation of ceramic matrix composites: Using the tantalum silicon ceramic precursor prepared in step ② as the reactant, the porous carbon / carbon composite material obtained in step ① was subjected to multiple impregnation, curing and pyrolysis by the impregnation / curing / pyrolysis PIP process until a density of 2.8 g / cm was obtained. 3 Ceramic-based composite materials; in each impregnation / curing / cracking round, the impregnation is first performed by vacuum impregnation, the vacuum impregnation pressure is 200 Pa, and then pressure impregnation is performed, the pressure of pressure impregnation is 1.5 MPa, the time of each vacuum impregnation is 1 hour, the time of each pressure impregnation is 1 hour, the curing temperature is 250°C, the time of each curing is 2 hours, the curing is carried out in an argon atmosphere, the cracking temperature is 1500°C, the time of each cracking is 2 hours, and the cracking is carried out in an argon atmosphere.

[0098] ④ Ceramic matrix sintering reaction: Place the ceramic matrix composite material obtained in step ③ in a high-temperature furnace body, seal it, evacuate it to a pressure of 30 Pa, turn off the vacuum pump, introduce argon to normal pressure, and repeat this step at least once to exhaust the air in the cavity; then, introduce argon into the high-temperature furnace body to 5.0 MPa, raise the temperature to 1700°C, and sinter at this temperature for 2 hours; after the above-mentioned high-temperature and high-pressure reaction is completed, cool it down by program control at a cooling rate of 3°C / min. After cooling to room temperature, stop introducing argon and return it to atmospheric pressure; then remove the sample to obtain the sintered ceramic matrix composite material.

[0099] Ablation and erosion resistance test: The linear ablation rate of the sintered ceramic matrix composite material obtained in this comparative example in the oxyacetylene ablation environment was measured to be 5.3×10 -3 mm / s.

[0100] Comparative Example 3

[0101] ① Providing a porous carbon / carbon composite material: providing a punctured carbon fiber preform, wherein the density of the punctured carbon fiber preform is 0.5 g / cm 3A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the punctured carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.8 g / cm 3 .

[0102] ② Preparation of ceramic matrix composites: Using oxygen-free tantalum carbide ceramic precursor as the reactant, the porous carbon / carbon composite material obtained in step ① was subjected to multiple impregnation, curing and pyrolysis by the impregnation / curing / pyrolysis PIP process until a density of 2.8 g / cm was obtained. 3 Ceramic-based composite materials; in each impregnation / curing / cracking round, the impregnation is first performed by vacuum impregnation, the vacuum impregnation pressure is 200 Pa, and then pressure impregnation is performed, the pressure of pressure impregnation is 1.5 MPa, the time of each vacuum impregnation is 1 hour, the time of each pressure impregnation is 1 hour, the curing temperature is 250°C, the time of each curing is 2 hours, the curing is carried out in an argon atmosphere, the cracking temperature is 1500°C, the time of each cracking is 2 hours, and the cracking is carried out in an argon atmosphere.

[0103] ③ Ceramic matrix sintering reaction: The ceramic matrix composite material obtained in step ② is placed in a high-temperature furnace body, sealed, and vacuumed to a pressure of 30 Pa. The vacuum pump is turned off and argon is introduced to atmospheric pressure. This step is repeated at least once to exhaust the air in the cavity. Then, argon is introduced into the high-temperature furnace body to 5.0 MPa, the temperature is raised to 1700°C, and the temperature is kept for sintering for 2 hours. After the above-mentioned high-temperature and high-pressure reaction is completed, the temperature is controlled to be lowered at a rate of 3°C / min. After cooling to room temperature, the argon introduction is stopped and the pressure is restored to atmospheric pressure. The sample is then removed to obtain the sintered ceramic matrix composite material.

[0104] Ablation and erosion resistance test: The linear ablation rate of the sintered ceramic matrix composite material obtained in this comparative example in the oxyacetylene ablation environment was measured to be 4.9×10 -3 mm / s.

[0105] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a ceramic-based composite material with a high sintering degree, characterized in that: The method comprises the following steps: (1) Providing porous carbon / carbon composite materials; (2) uniformly mixing an oxygen-free tantalum carbide ceramic precursor and polytitanium oxide to obtain a tantalum-titanium ceramic precursor; the molar ratio of tantalum contained in the oxygen-free tantalum carbide ceramic precursor to titanium contained in the polytitanium oxide is 10: (0.3-0.8); (3) reacting the tantalum-titanium ceramic precursor with the porous carbon / carbon composite material by an impregnation pyrolysis method to obtain a ceramic-based composite material; (4) Sintering the ceramic-based composite material under high temperature and high pressure conditions of 1650-1850° C. and 3.5-9.0 MPa to obtain a ceramic-based composite material with a high sintering degree.

2. The preparation method according to claim 1, characterized in that The preparation of the oxygen-free tantalum carbide ceramic precursor is as follows: The tantalum penta(dimethylamino) or tantalum penta(diethylamino) is subjected to an amine exchange reaction with an amine compound, and then subjected to reduced pressure distillation to obtain an oxygen-free tantalum carbide ceramic precursor; The amine compound is one or more of di-n-propylamine, diisopropylamine, diallylamine, di-n-butylamine, diisobutylamine, di-n-pentylamine, tetrahydropyrrole, and hexahydropyridine.

3. The preparation method according to claim 1, characterized in that Step (4) includes the following sub-steps: (a) placing the ceramic matrix composite material obtained in step (3) in a furnace, sealing it and evacuating it, and then introducing an inert gas into the furnace to remove oxygen; (b) introducing an inert gas into the furnace body treated in step (a) to a pressure of 3.5-9.0 MPa, raising the temperature to 1650-1850° C. and sintering for 1-3 hours to obtain a ceramic-based composite material with a high sintering degree.

4. The preparation method according to claim 1, wherein: The density of the porous carbon / carbon composite material is 0.75-1.2 g / cm 3 .

5. The preparation method according to claim 1, wherein: In the impregnation cracking method in step (3), the cracking temperature is 1450~1600℃.

6. The preparation method according to claim 1, wherein: The density of the ceramic matrix composite material obtained in step (3) is 2.5~3.0g / cm 3 .

7. The preparation method according to claim 1, wherein: The linear ablation rate of the high-sintering degree ceramic matrix composite material in the oxyacetylene ablation test is less than 1×10 -3 mm / s.

8. The preparation method according to any one of claims 1 to 7, characterized in that The porous carbon / carbon composite material is a porous carbon / carbon composite material having a tantalum carbide interface layer, and the preparation of the porous carbon / carbon composite material having a tantalum carbide interface layer comprises the following steps: S1, alternately stacking carbon cloth and nickel foam sheets, and then using a puncture process to form a preform; S2. Depositing pyrolytic carbon and graphene in the preform by chemical vapor deposition, and then soaking the preform in an acid solution to remove the nickel foam, thereby obtaining a porous carbon / carbon composite material; S3. Using an oxygen-free tantalum carbide ceramic precursor as a reactant, depositing a tantalum carbide interface layer in the porous carbon / carbon composite material by chemical vapor deposition to obtain a porous carbon / carbon composite material having a tantalum carbide interface layer.

9. A ceramic-based composite material with a high sintering degree obtained by the preparation method according to any one of claims 1 to 8.

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