A toughened ceramic matrix composite material and its preparation method

Abstract

The present invention relates to a toughened ceramic-based composite material and a preparation method thereof. The method comprises the following steps: providing a porous carbon / carbon composite material and performing a hydrophilization treatment to obtain a hydrophilized porous carbon / carbon composite material; immersing the hydrophilized porous carbon / carbon composite material in a fullerene aqueous solution and subjecting the hydrophilized porous carbon / carbon composite material to a high-temperature treatment to obtain a porous carbon / carbon composite material compounded with fullerene; using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, depositing a zirconium carbide-silicon carbide composite interface layer by chemical vapor deposition to obtain a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer; reacting the zirconium carbide-silicon carbide composite ceramic precursor with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation cracking method to obtain a toughened ceramic-based composite material. The present invention can significantly improve the toughness of a ceramic matrix and enhance the mechanical properties of the composite material under a high-temperature aerobic environment.

Description

Technical Field

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

[0002] Carbide ceramics represented by zirconium carbide and boride ceramics represented by zirconium boride both have extremely excellent properties such as high strength, high modulus, ultra-high melting point and ablation resistance. However, their poor toughness makes them very easy to form through cracks, causing irreversible losses. Therefore, many scientific and technological workers have developed various methods to improve the toughness of ceramics. Carbon fiber-reinforced ceramic-based composites have the advantages of low density, high strength, high temperature resistance, and ablation resistance. At the same time, their toughness is significantly improved compared to pure ceramics, which has attracted widespread attention and become the main candidate material for ultra-high temperature resistant thermal structural materials. In the preparation technology of carbon fiber-reinforced ceramic-based composites, carbon fibers are usually woven into preforms of specific shapes and sizes, and then the ceramics are dispersed in the pores inside the carbon fiber preforms through grouting, infiltration, impregnation and cracking techniques. Based on this, the carbon fibers and the ceramic matrix cannot be well and evenly dispersed, and the ceramic matrix is prone to excessive aggregation in some areas, and the toughness of this part of the ceramic matrix is still poor, which has a negative impact on the overall toughness of the composite material. Therefore, how to further improve the toughness of ceramic-based composites and ensure their mechanical properties in extreme environments has become a key research issue in this technical field. Summary of the Invention

[0003] To address one or more technical problems existing in the prior art, the present invention provides a toughened ceramic matrix composite material and a method for preparing the same. This invention addresses the general toughness issues of existing carbon fiber-reinforced ceramic matrix composites, improving their toughness and mechanical properties in extreme environments.

[0004] In a first aspect, the present invention provides a method for preparing a toughened ceramic matrix composite material, the method comprising the following steps:

[0005] (1) Providing a porous carbon / carbon composite material;

[0006] (2) subjecting the porous carbon / carbon composite material to a hydrophilic treatment to obtain a hydrophilic porous carbon / carbon composite material;

[0007] (3) soaking the hydrophilized porous carbon / carbon composite material in a fullerene aqueous solution and subjecting it to high temperature treatment to obtain a porous carbon / carbon composite material containing fullerene;

[0008] (4) using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, depositing a zirconium carbide-silicon carbide composite interface layer in the porous carbon / carbon composite material containing fullerene by chemical vapor deposition, thereby obtaining a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer;

[0009] (5) reacting a zirconium carbide-silicon carbide composite ceramic precursor with the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation pyrolysis method to obtain a toughened ceramic matrix composite material; in steps (4) and (5), the zirconium carbide-silicon carbide composite ceramic precursor is obtained by compounding an oxygen-free zirconium carbide ceramic precursor with polycarbosilane.

[0010] In a second aspect, the present invention provides a strengthened and toughened ceramic-based composite material 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 introduces fullerenes into the composite material through a chemical modification method. By covalently linking the fullerenes with pyrolytic carbon, the fullerenes are stably and uniformly embedded in the composite material, preventing them from escaping. This allows for adjustable fullerene volume fraction, which is beneficial for strengthening and toughening the ceramic-based composite material.

[0013] (2) The present invention introduces a zirconium carbide-silicon carbide composite interface layer on the surface of pyrolytic carbon and fullerene by chemical vapor deposition. Silicon carbide and zirconium carbide will work in different temperature ranges, and can play a synergistic anti-oxidation effect, greatly enhancing the anti-oxidation ability of pyrolytic carbon and fullerene. The fullerene protected by the zirconium carbide-silicon carbide composite interface layer acts as a toughening phase, which significantly improves the strengthening and toughness of the ceramic-based composite material, and greatly improves the mechanical properties and toughness of the ceramic-based composite material in a high-temperature air environment.

[0014] (3) The present invention adopts chemical vapor deposition technology, uses zirconium carbide-silicon carbide composite ceramic precursor as a reactant, and introduces a zirconium carbide-silicon carbide composite interface layer between the carbon fiber pyrolytic carbon interface layer and the fullerene surface. Compared with the introduction of the silicon carbide interface layer, the composite material can significantly improve the oxidation resistance and toughness in a high-temperature oxygen environment. In addition, the present invention uses a new oxygen-free zirconium carbide ceramic precursor and polycarbosilane as a composite ceramic precursor for chemical vapor deposition and impregnation cracking, which can achieve the molding of zirconium carbide and silicon carbide and can make zirconium carbide and silicon carbide uniformly distributed. Compared with the use of a ceramic precursor formed by mixing polycarbosilane and other conventional zirconium carbide precursors, the present invention effectively improves the oxidation resistance and high-temperature mechanical properties of the ceramic-based composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is a microstructure diagram (SEM diagram) of the strengthened and toughened ceramic-based composite material obtained in Example 1 of the present invention. 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 toughened ceramic matrix composite material, the method comprising the following steps:

[0018] (1) Providing a porous carbon / carbon composite material; 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, 0.4 to 0.7 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, 0.7 to 1.0 g / cm 3 In the present invention, pyrolytic carbon (pyrolytic carbon) is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition technology, which is a conventional technology in the art;

[0019] (2) subjecting the porous carbon / carbon composite material to a hydrophilic treatment to obtain a hydrophilic porous carbon / carbon composite material; in the present invention, specifically, the inner surface of the porous carbon / carbon composite material is treated by solution impregnation, so that the pyrolytic carbon of the composite material is modified with a large number of hydrophilic chemical functional groups such as hydroxyl groups and / or carboxyl groups;

[0020] (3) soaking the hydrophilized porous carbon / carbon composite material in a fullerene aqueous solution for a period of, for example, 2 to 5 hours (e.g., 2, 3, 4, or 5 hours), and subjecting the mixture to a high-temperature treatment to obtain a porous carbon / carbon composite material composited with fullerene (also referred to as a fullerene covalently modified porous carbon / carbon composite material); in the present invention, specifically, a fullerene aqueous solution of a certain concentration is prepared, the hydrophilized porous carbon / carbon composite material obtained in step (2) is immersed therein, and subjected to a high-temperature treatment to form a covalent bond between the fullerene and the pyrolytic carbon, thereby obtaining a porous carbon / carbon composite material composited with fullerene;

[0021] (4) using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, depositing a zirconium carbide-silicon carbide composite interface layer in the porous carbon / carbon composite material composited with fullerene by chemical vapor deposition, thereby obtaining a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer; specifically, for example, placing the porous carbon / carbon composite material composited with fullerene in a chemical vapor deposition furnace, controlling the heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor, introducing nitrogen and hydrogen under vacuum and high temperature conditions, and forming a zirconium carbide-silicon carbide composite interface layer on the surfaces of the pyrolytic carbon and the fullerene after a certain period of time;

[0022] (5) reacting the zirconium carbide-silicon carbide composite ceramic precursor with the carbon / carbon composite material having the zirconium carbide-silicon carbide composite interface layer by an impregnation cracking method (impregnation / curing / cracking PIP process) to obtain a toughened ceramic matrix composite material; in other words, in step (5) of the present invention, the zirconium carbide-silicon carbide composite ceramic precursor is used as a reactant, and the toughened ceramic matrix composite material is prepared by precursor impregnation cracking, that is, the zirconium carbide-silicon carbide composite ceramic precursor is used as a reactant, and the zirconium carbide-silicon carbide composite ceramic precursor is filled in the pores by vacuum and pressure impregnation, and finally a toughened ceramic matrix composite material is formed by a curing cracking process; in steps (4) and (5), the zirconium carbide-silicon carbide composite ceramic precursor is made of oxygen-free carbonized A zirconium ceramic precursor is compounded with polycarbosilane. Preferably, the molar ratio of zirconium contained in the oxygen-free zirconium carbide ceramic precursor to silicon contained in the polycarbosilane is 1:(0.8-1.2). Specifically, for example, the liquid oxygen-free zirconium carbide ceramic precursor and the liquid polycarbosilane are stirred at a rotation speed of 100-400 rpm for 1-5 hours to obtain the zirconium carbide-silicon carbide composite ceramic precursor. The present invention does not specifically limit the source of polycarbosilane, and can use products that can be directly purchased or products synthesized by existing methods. In the present invention, the zirconium carbide-silicon carbide composite ceramic precursor obtained by uniformly mixing the oxygen-free zirconium carbide ceramic precursor and polycarbosilane is beneficial to avoid the agglomeration of zirconium and silicon, thereby facilitating the uniform dispersion of the two.

[0023] The present invention chemically modifies the porous carbon / carbon composite material so that fullerene forms a covalent bond with pyrolytic carbon, stably and uniformly embeds the fullerene within the composite material, making it less likely to be lost. The volume proportion of fullerene can be adjusted to 1-4%, and a zirconium carbide-silicon carbide composite interface layer is introduced to achieve uniform dispersion of fullerene-zirconium carbide-silicon carbide composite particles as a toughening phase in the ceramic matrix. The present invention can significantly improve the toughness of the ceramic matrix, enhance the mechanical properties of the composite material in a high-temperature aerobic environment, and solve the problem of general toughness of ceramic-based composite materials in traditional technologies.

[0024] The present invention introduces a zirconium carbide-silicon carbide composite interface layer on the surface of pyrolytic carbon and fullerene through the method of chemical vapor deposition. Silicon carbide and zirconium carbide will work in different temperature ranges, and can have a synergistic antioxidant effect, which greatly enhances the antioxidant ability of pyrolytic carbon and fullerene. The fullerene protected by the zirconium carbide-silicon carbide composite interface layer serves as a toughening phase, which significantly improves the strength and toughness of the ceramic-based composite material, and greatly improves the mechanical properties of the ceramic-based composite material in a high-temperature air environment.

[0025] According to some preferred embodiments, the preparation of the oxygen-free zirconium carbide ceramic precursor is as follows: tetrakis(dimethylamino)zirconium or tetrakis(diethylamino)zirconium is subjected to an amine exchange reaction with an amine compound, and then subjected to reduced pressure distillation to obtain the oxygen-free zirconium 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 The reaction is carried out in an inert gas atmosphere, such as an argon atmosphere; the molar ratio of tetrakis(dimethylamino)zirconium or tetrakis(diethylamino)zirconium to the amine compound is 1:(1-4); the temperature of the amine exchange reaction is 60°C-70°C, and the time is 12-18 hours; the present invention uses amino groups as ligands to stabilize the metal center, so that the prepared oxygen-free zirconium carbide ceramic precursor does not contain oxygen elements, can achieve direct molding of zirconium 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 zirconium carbide ceramic precursor is liquid.

[0026] According to some preferred embodiments, in step (1), the density of the porous carbon / carbon composite material is 0.7 to 1.0 g / cm 3 (e.g. 0.7, 0.8, 0.9 or 1 g / cm 3 ).

[0027] According to some preferred embodiments, the hydrophilization treatment is to immerse the porous carbon / carbon composite material in a mixed solution of concentrated sulfuric acid and hydrogen peroxide containing a volume ratio of (6 to 8): (2 to 4) (for example, 6:4, 7:3 or 8:2) at 85 to 98 ° C (for example, 85 ° C, 88 ° C, 90 ° C, 92 ° C, 95 ° C or 98 ° C) for at least 1 hour, and then soak and dry in distilled water to obtain a hydrophilized porous carbon / carbon composite material; in the present invention, the distilled water soaking is, for example, distilled water soaking at room temperature for 0.5 to 2 hours, and in the present invention, the room temperature is, for example, room temperature 15 to 35 ° C; the present invention does not specifically limit drying, which is a conventional technology in the art; in the present invention, preferably, soaking in a mixture of concentrated sulfuric acid and hydrogen peroxide containing a volume ratio of (6 to 8): ( 2~4) (for example, 6:4, 7:3 or 8:2) in a mixed solution of concentrated sulfuric acid and hydrogen peroxide for not less than 1 hour. Generally speaking, the longer the immersion and holding time, the higher the content of hydrophilic functional groups, which is conducive to covalently connecting more fullerenes and increasing the proportion of fullerenes in the fullerene covalently modified porous carbon / carbon composite material; the present invention finds that if the immersion and holding time is less than 1 hour, the hydrophilic functional groups formed on the surface are too few, and multiple immersions may be required to achieve the effect, thereby having a negative impact on the overall molding efficiency of the composite material; in the present invention, the concentrated sulfuric acid is, for example, concentrated sulfuric acid with a mass fraction of 98wt% (abbreviated as 98% concentrated sulfuric acid), and the hydrogen peroxide is, for example, hydrogen peroxide with a mass fraction of 30wt% (abbreviated as 30% hydrogen peroxide).

[0028] According to some specific embodiments, the hydrophilization treatment is to immerse the porous carbon / carbon composite material in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3, and then place it in an 85-98°C oil bath for at least 1 hour. After the treatment, the porous carbon / carbon composite material is taken out and immersed in distilled water, and then dried before use. The inner surface of the porous carbon / carbon composite material is modified with a large number of hydrophilic chemical functional groups such as hydroxyl and / or carboxyl groups. Specifically, a large number of hydrophilic functional groups such as hydroxyl and / or carboxyl groups are formed on the surface of the pyrolytic carbon inside the porous carbon / carbon composite material. In the present invention, the content of the hydrophilic functional groups can be regulated by controlling the time of the mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3.

[0029] According to some preferred embodiments, in step (3): the concentration of the fullerene aqueous solution is 0.3-1.6 mg / mL (for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 or 1.6 mg / mL); the volume percentage of fullerene in the porous carbon / carbon composite material containing fullerene is 1-4% (for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4%); the high temperature treatment is carried out under an inert atmosphere; and / or the temperature of the high temperature treatment is 400-600°C (for example, 400°C, 450°C, 500°C, 550°C or 600°C), and the time of the high temperature treatment is 2-5 h (for example, 2, 3, 4 or 5 h).

[0030] In the present invention, the fullerenes in the fullerene aqueous solution are chemically treated, and have hydrophilic functional groups such as hydroxyl and / or carboxyl groups on their surfaces, so that they can be well dispersed in water. The concentration of fullerene in the fullerene aqueous solution is preferably 0.3-1.6 mg / mL. The hydrophilized porous carbon / carbon composite material can be immersed in the fullerene aqueous solution by, for example, introducing an auxiliary method such as ultrasound, and then taken out and placed in a high-temperature furnace, and heated to 400-600° C. under the protection of an inert atmosphere, so that the fullerenes having hydrophilic functional groups are covalently linked to the pyrolytic carbon. Through this method, the volume proportion of fullerene in the porous carbon / carbon composite material containing fullerene can reach, for example, 1-4%. The present invention does not specifically limit ultrasound, and conventional ultrasonic treatment conditions can be used.

[0031] The present invention found that one of the key points of the present invention is that by limiting the concentration of the fullerene aqueous solution to 0.3-1.6 mg / mL, the volume fraction of fullerene in the porous carbon / carbon composite material can be controlled to 1-4%, so as to effectively play the role of toughening the ceramic-based composite material; generally speaking, the higher the concentration of the fullerene solution, the higher the volume fraction of fullerene in the porous carbon / carbon composite material. However, the present invention found that when the concentration of the fullerene solution is lower than 0.3 mg / mL, a large number of hydrophilic functional groups on the surface of the pyrolytic carbon remain unreacted, resulting in the volume fraction of fullerene in the porous carbon / carbon composite material being lower than 1%, and unable to achieve a good toughening effect; and when the concentration of the fullerene solution is higher than 1.6 mg / mL, the high concentration leads to a higher solution viscosity, resulting in poor fluidity of the fullerene solution in the pores of the porous carbon / carbon composite material, unable to achieve good filling, and also resulting in the volume fraction of fullerene in the porous carbon / carbon composite material being lower than 1%, unable to achieve a good toughening effect.

[0032] In the present invention, the fullerene is chemically treated, and the chemical treatment comprises: immersing the fullerene in a mixed solution of concentrated sulfuric acid and hydrogen peroxide in a volume ratio of (6-8):(2-4) (e.g., 6:4, 7:3, or 8:2) at 85-98°C (e.g., 85°C, 88°C, 90°C, 92°C, 95°C, or 98°C) for at least 1 hour, followed by immersion in distilled water and drying. At this point, the surface of the fullerene is modified with a large number of hydrophilic chemical functional groups such as hydroxyl and / or carboxyl groups, exhibiting good dispersibility in water; the distilled water immersion is, for example, immersion in distilled water at room temperature for 0.5-2 hours; the concentrated sulfuric acid is, for example, 98 wt% concentrated sulfuric acid, and the hydrogen peroxide is, for example, 30 wt% hydrogen peroxide.

[0033] According to some preferred embodiments, the zirconium carbide-silicon carbide composite ceramic precursor is heated and then introduced into a chemical vapor deposition furnace through a carrier gas nitrogen, and hydrogen is simultaneously introduced into the chemical vapor deposition furnace to deposit the zirconium carbide-silicon carbide composite interface layer; preferably, the volume flow ratio of nitrogen to hydrogen is 10:(2-5) (for example, 10:2, 10:2.5, 10:3, 10:3.5, 10:4, 10:4.5 or 10:5); preferably, the flow rate of the nitrogen is 0.5-3 L / min (for example, 0.5, 1, 1.5, 2, 2.5 or 3 L / min).

[0034] In the present invention, when chemical vapor deposition of the zirconium carbide-silicon carbide composite interface layer, a zirconium carbide-silicon carbide composite ceramic precursor obtained by compounding an oxygen-free zirconium carbide ceramic precursor and polycarbosilane is used as a reactant, wherein the polycarbosilane can also serve as a carbon source. When depositing the zirconium carbide-silicon carbide composite interface layer, no methane is required. The present invention preferably controls the flow ratio of nitrogen to hydrogen to be 10:(2-5) and the nitrogen flow rate to be 0.5-3 L / min, so as to achieve the control of the thickness of the zirconium carbide-silicon carbide composite interface layer to be 50-500 nm, ensure the formation of the zirconium carbide-silicon carbide composite interface layer, effectively play an antioxidant effect, and effectively protect the fullerene toughening phase in a high-temperature air environment, thereby significantly improving the strengthening and toughening of the ceramic-based composite material, and greatly improving the mechanical properties of the ceramic-based composite material in a high-temperature air environment. The present invention found that when the flow rate ratio of nitrogen to hydrogen is higher than 10:5 or lower than 10:2, the zirconium carbide-silicon carbide composite ceramic precursor is more likely to deposit and form pyrolytic carbon, rather than a complete zirconium carbide-silicon carbide composite interface layer, which cannot effectively protect fullerenes in high-temperature air environments. Generally speaking, when the flow rate ratio of nitrogen to hydrogen is constant, the greater the nitrogen flow rate, the thicker the zirconium carbide-silicon carbide composite interface layer. When the thickness of the composite interface layer is less than 50nm, the interface layer distribution is uneven, and it cannot provide a good antioxidant effect. When the thickness of the composite interface layer is greater than 500nm, the pore size within the composite material also decreases. Due to the relatively large molecular size of the zirconium carbide-silicon carbide composite ceramic precursor, it is difficult to achieve uniform penetration within the composite material, resulting in a dense outer layer and a loose inner structure. This greatly affects the subsequent precursor impregnation and cracking effect, thereby affecting the mechanical properties of the ceramic matrix composite material.

[0035] According to some preferred embodiments, the heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is 90-150°C (for example, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C); and / or the temperature for depositing the zirconium carbide-silicon carbide composite interface layer is 1000-1300°C (for example, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C or 1300°C), the time is 1-3h (for example, 1, 1.5, 2, 2.5 or 3h), and the pressure in the chemical vapor deposition furnace is 10-150Pa (for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150Pa); in the present invention, the pressures involved refer to absolute pressures.

[0036] According to some specific embodiments, step (4) is: placing the fullerene covalently modified porous carbon / carbon composite material in a chemical vapor deposition furnace, evacuating the reaction furnace, and maintaining the pressure in the reaction furnace at 10-150 Pa. At the same time, the temperature in the reaction furnace is controlled at 1000-1300° C., and the temperature is maintained for 10-30 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor is brought into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is controlled at 90-150° C. While maintaining the carrier gas continuously carrying the zirconium carbide-silicon carbide composite ceramic precursor into the cavity, hydrogen is also introduced into the chemical vapor deposition furnace cavity (furnace cavity), and the volume flow ratio of the carrier gas nitrogen and hydrogen is controlled to be 10:2-5, wherein the nitrogen flow rate is controlled at 0.5-3 L / min. After the reactor is kept warm for 1-3 hours, a zirconium carbide-silicon carbide composite interface layer with a thickness of 50-500 nm forms on the surfaces of the pyrolytic carbon and fullerenes. The temperature is then lowered, and heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen are stopped. Nitrogen is maintained throughout the cooling process until the sample reaches room temperature, at which point it is removed.

[0037] According to some preferred embodiments, the thickness of the zirconium carbide-silicon carbide composite interface layer is 50 to 500 nm (e.g., 50, 100, 150, 200, 250, 300, 350, 400, 450 or 500 nm), more preferably 150 to 280 nm (e.g., 150, 180, 200, 250 or 280 nm); and / or the density of the toughened ceramic matrix composite material is 2.3 to 2.7 g / cm 3 (e.g. 2.3, 2.4, 2.5, 2.6 or 2.7 g / cm 3 In the present invention, the precursor can be impregnated and cracked by multiple impregnation curing and cracking treatments to prepare a density of 2.3-2.7g / cm 3 Strengthened and toughened ceramic matrix composites.

[0038] According to some preferred embodiments, step (5) includes the following sub-steps:

[0039] (a) sequentially vacuum impregnating and pressure impregnating the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer using a zirconium carbide-silicon carbide composite ceramic precursor; preferably, the total time of the vacuum impregnation and pressure impregnation is 60 to 360 minutes (e.g., 60, 120, 180, 240, 300, or 360 minutes);

[0040] (b) curing the carbon / carbon composite material having the zirconium carbide-silicon carbide composite interface layer treated in step (a) in an inert atmosphere (e.g., argon) at 160-320° C. (e.g., 160° C., 200° C., 250° C., 300° C., or 320° C.), then placing it in a reaction furnace, sealing it, evacuating it, introducing an inert gas, and cracking it at 1400-1700° C. (e.g., 1400° C., 1500° C., 1600° C., or 1700° C.) for 1-360 min (e.g., 1, 30, 60, 90, 120, 150, 180, or 200° C.). , 210, 240, 270, 300, 330 or 360 min), preferably 120 to 240 min; preferably, the pressure in the reaction furnace is evacuated to 10 to 150 Pa; preferably, the flow rate of the inert gas is 300 to 3000 sccm (for example, 300, 600, 900, 1200, 1500, 1800, 2100, 2400, 2700 or 3000 sccm); preferably, the temperature is raised to 1400 to 1700° C. at a heating rate of 1 to 10° C. / min;

[0041] (c) After the cracking reaction in step (b) is completed, the temperature is cooled by program control at a cooling rate of 1 to 5°C / min. After cooling to room temperature, the introduction of the inert gas is stopped and the pressure is restored to atmospheric pressure;

[0042] (d) Repeating steps (a) to (c) at least once; preferably, repeating steps (a) to (c) 1 to 10 times.

[0043] According to some specific implementations, step (5) is:

[0044] (a) placing the carbon / carbon composite material having the zirconium carbide-silicon carbide composite interface layer obtained in step (4) into a zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is, for example, 10 to 150 Pa, and the vacuum impregnation time is 0.5 to 3 hours, and then pressure impregnation is performed, the pressure of the pressure impregnation is 1 to 2 MPa, and the pressure impregnation time is 0.5 to 3 hours;

[0045] (b) In an argon inert atmosphere and under heating conditions of 160-320° C., the zirconium carbide-silicon carbide composite ceramic precursor in the pores can be cross-linked and cured; the cross-linked and cured ceramic matrix composite material is placed in a reaction furnace, which is sealed, evacuated, and argon inert gas is introduced at a flow rate of 300-3000 sccm; the temperature is set to be programmed to increase at a rate of 1-10° C. / minute to 1400-1700° C., and the reaction is carried out for 1-360 minutes;

[0046] (c) After the cracking reaction in step (b) is completed, the temperature is cooled by program control at a cooling rate of 1 to 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure;

[0047] (d) Repeat steps (a) to (c) at least once.

[0048] In a second aspect, the present invention provides a toughened ceramic matrix composite material obtained by the preparation method described in the first aspect of the present invention; preferably, the toughened ceramic matrix composite material has a fracture toughness of not less than 15 MPa·m in an air environment at 1500°C. 1 / 2 The toughened ceramic matrix composite material prepared by the present invention has the advantage of toughening, which is manifested in a significant improvement in mechanical properties under high-temperature air environment.

[0049] 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.

[0050] The preparation of the oxygen-free zirconium carbide ceramic precursor involved in the following embodiments and comparative examples of the present invention is as follows:

[0051] The three-necked flask was repeatedly evacuated and filled with argon to replace the air, and tetrakis(dimethylamino)zirconium was added, followed by diallylamine. The mixture was stirred and reacted at 65°C in an argon atmosphere for 16 hours. The reactants were then distilled under reduced pressure to remove low-boiling point substances, thereby obtaining a liquid oxygen-free zirconium carbide ceramic precursor. The molar ratio of tetrakis(dimethylamino)zirconium to diallylamine was 1:1.

[0052] The zirconium carbide-silicon carbide composite ceramic precursor involved in the following embodiments and comparative examples of the present invention is prepared as follows:

[0053] The liquid oxygen-free zirconium carbide ceramic precursor and the liquid polycarbosilane are stirred at a rotation speed of 150 rpm for 4 hours to be evenly mixed to obtain the zirconium carbide-silicon carbide composite ceramic precursor; wherein the amount of the oxygen-free zirconium carbide ceramic precursor and the polycarbosilane is such that the molar ratio of zirconium contained in the oxygen-free zirconium carbide ceramic precursor to silicon contained in the polycarbosilane is 1:1.

[0054] Example 1

[0055] ① Providing porous carbon / carbon composite materials: providing a carbon fiber preform, the density of the carbon fiber preform is 0.5g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.75 g / cm 3 .

[0056] ② Modification of hydrophilic chemical functional groups: The porous carbon / carbon composite was immersed in a mixture of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3. The mixture was then kept in a 90°C oil bath for 2 hours. The mixture was then removed and immersed in distilled water at room temperature for 1.5 hours. Finally, the hydrophilized porous carbon / carbon composite was obtained by drying.

[0057] ③ Preparation of a porous carbon / carbon composite material containing fullerenes: The fullerenes were chemically treated by immersing them in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3 and then incubating in a 90°C oil bath for 2 hours. The fullerenes were then removed and immersed in distilled water at room temperature for 1.5 hours, followed by drying to obtain chemically treated fullerenes. The chemically treated fullerenes were then used to prepare a fullerene aqueous solution at a concentration of 0.5 mg / mL. The hydrophilized porous carbon / carbon composite material was immersed in the fullerene aqueous solution and ultrasonically treated for 3 hours. The hydrophilized porous carbon / carbon composite material was then removed and dried, placed in a high-temperature furnace, and heated to 500°C under an inert atmosphere of argon for 2 hours to obtain a porous carbon / carbon composite material containing fullerenes (i.e., a fullerene-covalently modified porous carbon / carbon composite material). The volume proportion of fullerene in the porous carbon / carbon composite material was 1.6%.

[0058] ④ Preparation of zirconium carbide-silicon carbide composite interface layer: The porous carbon / carbon composite material containing fullerene is placed in a chemical vapor deposition furnace (reactor), and the vacuum is drawn to a pressure of 50 Pa in the reactor. At the same time, the temperature in the reactor is controlled at 1100 ° C and kept warm for 15 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor is brought into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is controlled at 95 ° C. While maintaining the carrier gas continuously carrying the zirconium carbide-silicon carbide composite ceramic precursor into the cavity, hydrogen is also introduced into the chemical vapor deposition furnace cavity (furnace cavity), and the volume flow ratio of the carrier gas nitrogen and hydrogen is controlled to be 10:3, of which the nitrogen flow rate is controlled at 1.5 L / min. After the reactor was heated at 1100°C for 2 hours, a 150nm-thick zirconium carbide-silicon carbide composite interface layer formed on the surfaces of the pyrolytic carbon and fullerenes. The temperature was then lowered, and heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen were stopped. Nitrogen was maintained throughout the cooling process until the temperature reached room temperature, at which point the sample was removed, yielding a carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer.

[0059] ⑤ Preparation of toughened ceramic matrix composites: Using zirconium carbide-silicon carbide composite ceramic precursor as reactant, the zirconium carbide-silicon carbide composite ceramic precursor was reacted with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation / curing / cracking PIP process to prepare a ceramic matrix composite with a density of 2.4 g / cm 3 The strengthened and toughened ceramic matrix composite material, the specific impregnation cracking process includes the following sub-steps: (a) placing the carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer obtained in step ④ into a zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, the pressure of the pressure impregnation is 1.5MPa, and the pressure impregnation time is 1h; (b) the zirconium carbide-silicon carbide composite interface layer treated in step (a) is placed in the zirconium carbide-silicon carbide composite ceramic precursor. The carbon / carbon composite material is cured under an argon inert atmosphere and heating conditions of 200°C, and the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; the cross-linked and cured material is placed in a reaction furnace body, which is sealed, evacuated, and argon inert gas is introduced at a flow rate of 1000sccm; the temperature is set to be programmed to increase at a rate of 5°C / min to 1500°C and react for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is programmed to decrease at a rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) steps (a) to (c) are repeated 10 times.

[0060] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the toughened ceramic matrix composite material prepared in this embodiment is 16.9 MPa·m under 1500℃ air environment. 1 / 2 .

[0061] Example 2

[0062] ① Providing porous carbon / carbon composite materials: providing a carbon fiber preform, the density of the carbon fiber preform is 0.5g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.75 g / cm 3 .

[0063] ② Modification of hydrophilic chemical functional groups: The porous carbon / carbon composite was immersed in a mixture of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3. The mixture was then kept in a 90°C oil bath for 3 hours. The mixture was then removed and immersed in distilled water at room temperature for 1.5 hours. Finally, the hydrophilized porous carbon / carbon composite was obtained by drying.

[0064] ③ Preparation of a porous carbon / carbon composite material containing fullerene: The fullerene was chemically treated by immersing the fullerene in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3 and then keeping it in a 90°C oil bath for 2 hours. After the treatment, the fullerene was removed and immersed in distilled water at room temperature for 1.5 hours, and finally dried to obtain a chemically treated fullerene. The chemically treated fullerene was then used to prepare a fullerene aqueous solution with a concentration of 0.5 mg / mL. The hydrophilized porous carbon / carbon composite material was immersed in the fullerene aqueous solution and ultrasonically treated for 3 hours. It was then removed and dried, placed in a high-temperature furnace, and heated to 500°C under an inert atmosphere of argon for 2 hours to obtain a porous carbon / carbon composite material containing fullerene. The volume proportion of fullerene in the porous carbon / carbon composite material was 2.0%.

[0065] ④ Preparation of zirconium carbide-silicon carbide composite interface layer: The above-mentioned porous carbon / carbon composite material containing fullerene is placed in a chemical vapor deposition furnace, and the vacuum is drawn to a pressure of 50Pa in the reactor. At the same time, the temperature in the reactor is controlled at 1100°C and kept warm for 15 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor will be brought into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is controlled at 95°C. While maintaining the carrier gas continuously carrying the zirconium carbide-silicon carbide composite ceramic precursor into the cavity, hydrogen is also introduced into the chemical vapor deposition furnace cavity (furnace cavity), and the volume flow ratio of the carrier gas nitrogen and hydrogen is controlled to be 10:3, of which the nitrogen flow rate is controlled at 1.5L / min. After the reactor was heated at 1100°C for 2 hours, a 150nm-thick zirconium carbide-silicon carbide composite interface layer formed on the surfaces of the pyrolytic carbon and fullerenes. The temperature was then lowered, and heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen were stopped. Nitrogen was maintained throughout the cooling process until the temperature reached room temperature, at which point the sample was removed, yielding a carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer.

[0066] ⑤ Preparation of a toughened ceramic matrix composite material: Using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, the zirconium carbide-silicon carbide composite ceramic precursor is reacted with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation and cracking method (impregnation / curing / cracking PIP process) to prepare a toughened ceramic matrix composite material; the specific impregnation and cracking process includes the following sub-steps: (a) placing the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer obtained in step ④ into the zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, and the pressure impregnation The pressure is 1.5 MPa, and the pressure impregnation time is 1 hour; (b) curing the carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer treated in step (a) under an argon inert atmosphere and heating conditions of 200°C, so that the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; placing the cross-linked and cured material in a reaction furnace body, sealing, evacuating, and introducing argon inert gas at a flow rate of 1000sccm; setting a program to control the temperature to rise at a heating rate of 5°C / min to 1500°C and react for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled to fall at a cooling rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) repeating steps (a) to (c) 10 times.

[0067] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the toughened ceramic matrix composite material prepared in this embodiment is 18.5 MPa·m under 1500℃ air environment. 1 / 2 .

[0068] Example 3

[0069] ① Providing porous carbon / carbon composite materials: providing a carbon fiber preform, the density of the carbon fiber preform is 0.5g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.75 g / cm 3 .

[0070] ② Modification of hydrophilic chemical functional groups: The porous carbon / carbon composite was immersed in a mixture of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3. The mixture was then kept in a 90°C oil bath for 2 hours. The mixture was then removed and immersed in distilled water at room temperature for 1.5 hours. Finally, the hydrophilized porous carbon / carbon composite was obtained by drying.

[0071] ③ Preparation of a porous carbon / carbon composite material containing fullerenes: The fullerenes were chemically treated by immersing them in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3 and then keeping them in a 90°C oil bath for 2 hours. Afterwards, the fullerenes were removed and immersed in distilled water at room temperature for 1.5 hours, followed by drying to obtain chemically treated fullerenes. The chemically treated fullerenes were then used to prepare a fullerene aqueous solution at a concentration of 1.0 mg / mL. The hydrophilized porous carbon / carbon composite material was immersed in the fullerene aqueous solution and ultrasonically treated for 3 hours. The hydrophilized porous carbon / carbon composite material was then removed, dried, and placed in a high-temperature furnace. Under an inert atmosphere of argon, the temperature was raised to 500°C for 2 hours to obtain a porous carbon / carbon composite material containing fullerenes. The volume proportion of fullerene in the porous carbon / carbon composite material was 2.9%.

[0072] ④ Preparation of zirconium carbide-silicon carbide composite interface layer: The above-mentioned porous carbon / carbon composite material containing fullerene is placed in a chemical vapor deposition furnace, and the vacuum is drawn to a pressure of 50Pa in the reactor. At the same time, the temperature in the reactor is controlled at 1100°C and kept warm for 15 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor will be brought into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is controlled at 95°C. While maintaining the carrier gas continuously carrying the zirconium carbide-silicon carbide composite ceramic precursor into the cavity, hydrogen is also introduced into the chemical vapor deposition furnace cavity (furnace cavity), and the volume flow ratio of the carrier gas nitrogen and hydrogen is controlled to be 10:3, of which the nitrogen flow rate is controlled at 1.5L / min. After the reactor was heated at 1100°C for 2 hours, a 150nm-thick zirconium carbide-silicon carbide composite interface layer formed on the surfaces of the pyrolytic carbon and fullerenes. The temperature was then lowered, and heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen were stopped. Nitrogen was maintained throughout the cooling process until the temperature reached room temperature, at which point the sample was removed, yielding a carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer.

[0073] ⑤ Preparation of a toughened ceramic matrix composite material: Using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, the zirconium carbide-silicon carbide composite ceramic precursor is reacted with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation and cracking method (impregnation / curing / cracking PIP process) to prepare a toughened ceramic matrix composite material; the specific impregnation and cracking process includes the following sub-steps: (a) placing the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer obtained in step ④ into the zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, and the pressure impregnation The pressure is 1.5 MPa, and the pressure impregnation time is 1 hour; (b) curing the carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer treated in step (a) under an argon inert atmosphere and heating conditions of 200°C, so that the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; placing the cross-linked and cured material in a reaction furnace body, sealing, evacuating, and introducing argon inert gas at a flow rate of 1000sccm; setting a program to control the temperature to rise at a heating rate of 5°C / min to 1500°C and react for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled to fall at a cooling rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) repeating steps (a) to (c) 10 times.

[0074] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the toughened ceramic matrix composite material prepared in this embodiment is 21.9 MPa·m under 1500℃ air environment. 1 / 2 .

[0075] Example 4

[0076] ① Providing porous carbon / carbon composite materials: providing a carbon fiber preform, the density of the carbon fiber preform is 0.5g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.75 g / cm 3 .

[0077] ② Modification of hydrophilic chemical functional groups: The porous carbon / carbon composite was immersed in a mixture of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3. The mixture was then kept in a 90°C oil bath for 2 hours. The mixture was then removed and immersed in distilled water at room temperature for 1.5 hours. Finally, the hydrophilized porous carbon / carbon composite was obtained by drying.

[0078] ③ Preparation of a porous carbon / carbon composite material containing fullerenes: The fullerenes were chemically treated by immersing them in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3, and then keeping them in a 90°C oil bath for 2 hours. After the treatment, the fullerenes were removed and immersed in distilled water at room temperature for 1.5 hours, and finally dried to obtain chemically treated fullerenes. The chemically treated fullerenes were then used to prepare a fullerene aqueous solution at a concentration of 0.1 mg / mL. The hydrophilized porous carbon / carbon composite material was immersed in the fullerene aqueous solution and ultrasonically treated for 3 hours. The hydrophilized porous carbon / carbon composite material was then removed, dried, placed in a high-temperature furnace, and heated to 500°C under an inert atmosphere of argon for 2 hours to obtain a porous carbon / carbon composite material containing fullerenes. The volume proportion of fullerene in the porous carbon / carbon composite material containing fullerenes was 0.4%.

[0079] ④ Preparation of zirconium carbide-silicon carbide composite interface layer: The above-mentioned porous carbon / carbon composite material containing fullerene is placed in a chemical vapor deposition furnace, and the vacuum is drawn to a pressure of 50Pa in the reactor. At the same time, the temperature in the reactor is controlled at 1100°C and kept warm for 15 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor will be brought into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is controlled at 95°C. While maintaining the carrier gas continuously carrying the zirconium carbide-silicon carbide composite ceramic precursor into the cavity, hydrogen is also introduced into the chemical vapor deposition furnace cavity (furnace cavity), and the volume flow ratio of the carrier gas nitrogen and hydrogen is controlled to be 10:3, of which the nitrogen flow rate is controlled at 1.5L / min. After the reactor was heated at 1100°C for 2 hours, a 150nm-thick zirconium carbide-silicon carbide composite interface layer formed on the surfaces of the pyrolytic carbon and fullerenes. The temperature was then lowered, and heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen were stopped. Nitrogen was maintained throughout the cooling process until the temperature reached room temperature, at which point the sample was removed, yielding a carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer.

[0080] ⑤ Preparation of a toughened ceramic matrix composite material: Using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, the zirconium carbide-silicon carbide composite ceramic precursor is reacted with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation and cracking method (impregnation / curing / cracking PIP process) to prepare a toughened ceramic matrix composite material; the specific impregnation and cracking process includes the following sub-steps: (a) placing the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer obtained in step ④ into the zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, and the pressure impregnation The pressure is 1.5 MPa, and the pressure impregnation time is 1 hour; (b) curing the carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer treated in step (a) under an argon inert atmosphere and heating conditions of 200°C, so that the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; placing the cross-linked and cured material in a reaction furnace body, sealing, evacuating, and introducing argon inert gas at a flow rate of 1000sccm; setting a program to control the temperature to rise at a heating rate of 5°C / min to 1500°C and react for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled to fall at a cooling rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) repeating steps (a) to (c) 10 times.

[0081] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the ceramic matrix composite material prepared in this embodiment is 9.2 MPa·m under 1500℃ air environment. 1 / 2 .

[0082] As can be seen from Examples 1 to 4 above, compared with Example 1, in Example 2, the immersion time during the hydrophilization treatment is extended from 2 h to 3 h, which increases the content of hydrophilic functional groups on the surface of the pyrolytic carbon, and makes the contact sites with fullerene more sufficient, so that the volume proportion of fullerene increases from 1.6% to 2.0%, and the proportion of toughening phase increases, which leads to the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment increasing from 16.9 MPa·m 1 / 2 Increased to 18.5 MPa·m 1 / 2 Compared with Example 1, when preparing the fullerene aqueous solution in Example 3, the concentration was increased from 0.5 mg / mL to 1.0 mg / mL, which also increased the volume proportion of fullerene from 1.6% to 2.9%. The increase in the proportion of toughening phase increased the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment from 16.9 MPa·m 1 / 2 Increased to 21.9 MPa·m 1 / 2 Compared with Example 1, when preparing the fullerene aqueous solution in Example 4, the concentration was reduced from 0.5 mg / mL to 0.1 mg / mL, which also caused the volume proportion of fullerene to decrease from 1.6% to 0.4%. The proportion of toughening phase was greatly reduced, resulting in the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment decreasing from 16.9 MPa·m 1 / 2 Reduced to 9.2 MPa·m 1 / 2 .

[0083] Examples 5 to 13

[0084] The specific process parameters of Examples 5 to 13 and the performance indicators of the finally prepared ceramic matrix composite materials are shown in Table 1. The other preparation processes are the same as those of Example 1.

[0085]

[0086] As shown in Table 1, compared with Example 1, when preparing the fullerene aqueous solution, the concentration of Example 5 was reduced from 0.5 mg / mL to 0.3 mg / mL, which also caused the volume proportion of fullerene to decrease from 1.6% to 1.0%. The reduction in the proportion of the toughening phase resulted in the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment decreasing from 16.9 MPa·m 1 / 2 Reduced to 15.2 MPa·m 1 / 2Compared with Example 1, when preparing the fullerene aqueous solution in Example 6, the concentration was increased from 0.5 mg / mL to 1.6 mg / mL, which also increased the volume proportion of fullerene from 1.6% to 4.0%. The increase in the proportion of toughening phase increased the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment from 16.9 MPa·m 1 / 2 Increased to 24.1MPa·m 1 / 2 Compared with Example 1, when preparing the fullerene aqueous solution in Example 7, the concentration was increased from 0.5 mg / mL to 2.0 mg / mL, but the volume proportion of fullerene decreased from 1.6% to 0.9%. The main reason may be that the high concentration leads to a higher viscosity of the solution, which makes the fullerene aqueous solution have poor fluidity in the pores of the hydrophilized porous carbon / carbon composite material and cannot achieve good filling. The proportion of the toughening phase decreases, resulting in the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment decreasing from 16.9 MPa·m 1 / 2 Reduced to 13.8 MPa·m 1 / 2 Compared with Example 1, in Example 8, the immersion time during the hydrophilic treatment was shortened from 2 h to 0.5 h, which reduced the content of hydrophilic functional groups on the surface of the pyrolytic carbon and also caused the volume proportion of fullerene to decrease from 1.6% to 0.8%. The decrease in the proportion of toughening phase resulted in the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment decreasing from 16.9 MPa·m 1 / 2 Reduced to 11.3 MPa·m 1 / 2 Compared with Example 1, when the nitrogen flow rate is selected in Example 9, it is reduced from 1.5L / min to 0.3L / min, so that the thickness of the zirconium carbide-silicon carbide composite interface layer is reduced from 150nm to 30nm. The decrease in the thickness of the composite interface layer leads to the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment from 16.9MPa·m 1 / 2 Reduced to 12.6 MPa·m 1 / 2 Compared with Example 1, when the nitrogen flow rate is increased from 1.5L / min to 3L / min, Example 10 increases the thickness of the zirconium carbide-silicon carbide composite interface layer from 150nm to 280nm. The increase in the thickness of the composite interface layer promotes the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment from 16.9MPa·m 1 / 2 Increased to 20.6MPa·m 1 / 2 Compared with Example 1, Example 11 increases the nitrogen flow rate from 1.5 L / min to 6 L / min. The excessive nitrogen flow rate increases the thickness of the zirconium carbide-silicon carbide composite interface layer from 150 nm to 550 nm. However, the ceramic matrix composite material has a dense outer layer and a loose inner structure, which greatly affects the subsequent precursor impregnation and cracking effect, resulting in the fracture toughness of the ceramic matrix composite material in a high-temperature oxygen environment from 16.9 MPa·m 1 / 2 Reduced to 11.8 MPa·m 1 / 2Compared with Example 1, Example 12 changes the volume flow ratio of nitrogen and hydrogen from 10:3 to 10:1, which results in the formation of a large amount of carbon in the composite interface layer, rather than a complete zirconium carbide-silicon carbide composite interface layer. The oxidation resistance is significantly affected, resulting in the fracture toughness in a high-temperature oxygen environment being reduced from 16.9 MPa·m 1 / 2 Reduced to 7.3 MPa·m 1 / 2 Compared with Example 1, Example 13 changes the volume flow ratio of nitrogen and hydrogen from 10:3 to 10:8, which also results in the formation of a large amount of carbon in the composite interface layer instead of complete zirconium carbide-silicon carbide, which significantly affects the oxidation resistance and causes the fracture toughness in a high-temperature oxygen environment to decrease from 16.9 MPa·m 1 / 2 Reduced to 7.8 MPa·m 1 / 2 .

[0087] Comparative Example 1

[0088] ① Provide a carbon fiber preform, the density of the carbon fiber preform is 0.5g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.75 g / cm 3 .

[0089] ② Chemically treating the fullerene, comprising: immersing the fullerene in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3, and then maintaining the mixture in a 90°C oil bath for 2 hours. Afterwards, the fullerene was removed and immersed in distilled water at room temperature for 1.5 hours, followed by drying to obtain a chemically treated fullerene. The chemically treated fullerene was then used to prepare a fullerene aqueous solution at a concentration of 0.5 mg / mL. The porous carbon / carbon composite material from step ① was immersed in the fullerene aqueous solution and ultrasonically treated for 3 hours. The porous carbon / carbon composite material was then removed, dried, placed in a high-temperature furnace, and heated to 500°C under an inert atmosphere of argon for 2 hours to obtain a modified porous carbon / carbon composite material.

[0090] ③ The modified porous carbon / carbon composite material is placed in a chemical vapor deposition furnace. The vacuum is drawn to a pressure of 50 Pa in the reactor. The temperature in the reactor is controlled at 1100°C and maintained for 15 minutes to ensure a uniform temperature inside the furnace. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor is introduced into the chemical vapor deposition furnace chamber using nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is controlled at 95°C. While maintaining the carrier gas continuously carrying the zirconium carbide-silicon carbide composite ceramic precursor into the chamber, hydrogen is also introduced into the chemical vapor deposition furnace chamber (furnace chamber). The volume flow ratio of the carrier gas nitrogen and hydrogen is controlled to be 10:3, with the nitrogen flow rate controlled at 1.5 L / min. After the reactor is maintained at 1100°C for 2 hours, a zirconium carbide-silicon carbide composite interface layer with a thickness of 150 nm is formed. The temperature is then lowered, and the heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen are stopped in sequence. Nitrogen is kept introduced throughout the cooling process until it reaches room temperature. The sample is taken out to obtain a carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer.

[0091] ④ Using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, the zirconium carbide-silicon carbide composite ceramic precursor is reacted with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation and cracking method (impregnation / curing / cracking PIP process) to prepare a ceramic-based composite material; the specific impregnation and cracking process includes the following sub-steps: (a) placing the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer obtained in step ③ into the zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, and the pressure of the pressure impregnation is 1.5MPa , the pressure impregnation time is 1h; (b) curing the carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer treated in step (a) under an argon inert atmosphere and heating conditions of 200°C, so that the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; placing the cross-linked and cured material in a reaction furnace body, sealing, evacuating, and introducing argon inert gas at a flow rate of 1000sccm; setting a program to control the temperature to rise at a heating rate of 5°C / min, rising to 1500°C, and reacting for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled to fall at a cooling rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) repeating steps (a) to (c) 10 times.

[0092] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the ceramic matrix composite material prepared in this comparative example is 10.6 MPa·m under 1500℃ air environment. 1 / 2 .

[0093] The porous carbon / carbon composite material in this comparative example has not been treated with a mixed solution of concentrated sulfuric acid and hydrogen peroxide. Therefore, fullerene is difficult to be adsorbed on the inner surface of the porous carbon / carbon composite material, resulting in a poor toughening effect.

[0094] Comparative Example 2

[0095] ① Providing porous carbon / carbon composite materials: providing a carbon fiber preform, the density of the carbon fiber preform is 0.5g / cm 3 A pyrolytic carbon interface layer is deposited on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain a porous carbon / carbon composite material with a density of 0.75 g / cm 3 .

[0096] ② Preparation of the zirconium carbide-silicon carbide composite interface layer: The porous carbon / carbon composite material was placed in a chemical vapor deposition (CVD) furnace. The vacuum was evacuated to a pressure of 50 Pa (Pa). The temperature inside the reactor was controlled at 1100°C and held for 15 minutes to ensure a uniform temperature inside the furnace. Next, the heated zirconium carbide-silicon carbide composite ceramic precursor was introduced into the CVD furnace chamber using nitrogen as a carrier gas. The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor was controlled at 95°C. While maintaining the carrier gas carrying the zirconium carbide-silicon carbide composite ceramic precursor into the chamber, hydrogen was also introduced into the CVD furnace chamber (furnace chamber). The volume flow ratio of nitrogen and hydrogen was controlled to be 10:3, with the nitrogen flow rate controlled at 1.5 L / min. After the reactor was held at 1100°C for 2 hours, a zirconium carbide-silicon carbide composite interface layer with a thickness of 150 nm was formed. The temperature is then lowered, and the heating of the zirconium carbide-silicon carbide composite ceramic precursor and the introduction of hydrogen are stopped in sequence. Nitrogen is kept introduced throughout the cooling process until it reaches room temperature. The sample is taken out to obtain a carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer.

[0097] ③ Preparation of ceramic matrix composite materials: using zirconium carbide-silicon carbide composite ceramic precursor as reactant, reacting the zirconium carbide-silicon carbide composite ceramic precursor with a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a ceramic matrix composite material; the specific impregnation pyrolysis process includes the following sub-steps: (a) placing the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer obtained in step ② into the zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, and the pressure of the pressure impregnation is 1 .5MPa, and the pressure impregnation time is 1h; (b) curing the carbon / carbon composite material with a zirconium carbide-silicon carbide composite interface layer treated in step (a) in an argon inert atmosphere and heating conditions of 200°C, so that the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; placing the cross-linked and cured material in a reaction furnace body, sealing, evacuating, and introducing argon inert gas at a flow rate of 1000sccm; setting a program to control the temperature to rise at a rate of 5°C / min, rising to 1500°C, and reacting for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled to fall at a rate of 5°C / min, and after cooling to room temperature, the introduction of inert gas argon is stopped, and the pressure is restored to atmospheric pressure; (d) repeating steps (a) to (c) 10 times.

[0098] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the ceramic matrix composite material prepared in this comparative example is 10.1 MPa·m under 1500℃ air environment. 1 / 2 .

[0099] Comparative Example 3

[0100] ① is the same as step ① in Example 1.

[0101] ② is the same as step ② of Example 1.

[0102] ③ is the same as step ③ of Example 1.

[0103] ④ Preparation of zirconium carbide interface layer: The above-mentioned porous carbon / carbon composite material containing fullerene is placed in a chemical vapor deposition furnace, and the vacuum is drawn to a pressure of 50Pa in the reactor. At the same time, the temperature in the reactor is controlled at 1100°C and kept warm for 15 minutes to ensure that the temperature inside the furnace reaches a uniform state. Next, the heated oxygen-free zirconium carbide ceramic precursor is brought into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas. The heating temperature of the oxygen-free zirconium carbide ceramic precursor is controlled at 95°C. While maintaining the carrier gas continuously carrying the oxygen-free zirconium carbide ceramic precursor into the cavity, hydrogen and methane are also introduced into the chemical vapor deposition furnace cavity (furnace cavity). The volume flow ratio of the three carrier gases, nitrogen, hydrogen, and methane, is controlled to be 10:6:5, of which the nitrogen flow rate is controlled at 1.5L / min. After the reactor is kept at 1100°C for 2 hours, a zirconium carbide interface layer is formed. The temperature is then lowered, and heating of the oxygen-free zirconium carbide ceramic precursor and introduction of hydrogen are stopped in sequence. Nitrogen is introduced throughout the entire cooling process until the temperature drops to room temperature. The sample is taken out to obtain a carbon / carbon composite material with a zirconium carbide interface layer.

[0104] ⑤ Preparation of ceramic matrix composite material: using oxygen-free zirconium carbide ceramic precursor as reactant, reacting oxygen-free zirconium carbide ceramic precursor with carbon / carbon composite material having zirconium carbide interface layer by impregnation pyrolysis method (impregnation / curing / pyrolysis PIP process), thereby preparing ceramic matrix composite material; the specific impregnation pyrolysis process includes the following sub-steps: (a) placing the carbon / carbon composite material having zirconium carbide interface layer obtained in step ④ into oxygen-free zirconium carbide ceramic precursor, and filling the oxygen-free zirconium carbide ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the pressure of the vacuum impregnation is 150Pa, the time of the vacuum impregnation is 1h, and then pressure impregnation is performed, the pressure of the pressure impregnation is 1.5MPa, and the pressure impregnation is performed. The impregnation time is 1h; (b) the carbon / carbon composite material with the zirconium carbide interface layer treated in step (a) is cured in an argon inert atmosphere and heated at 200°C, so that the oxygen-free zirconium carbide ceramic precursor inside the pores can be cross-linked and cured; the cross-linked and cured material is placed in a reaction furnace body, sealed, evacuated, and argon inert gas is introduced at a flow rate of 1000sccm; the temperature is set to be controlled by program at a heating rate of 5°C / min to 1500°C and the reaction is carried out for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled by program at a cooling rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) steps (a) to (c) are repeated 10 times.

[0105] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the ceramic matrix composite material prepared in this comparative example is 13.6MPa·m under 1500℃ air environment. 1 / 2 .

[0106] Comparative Example 4

[0107] ① is the same as step ① in Example 1.

[0108] ② is the same as step ② of Example 1.

[0109] ③ is the same as step ③ of Example 1.

[0110] ④ Preparation of silicon carbide interface layer: The above-mentioned porous carbon / carbon composite material composited with fullerene is placed in a chemical vapor deposition furnace, and a silicon carbide interface layer (SiC interface layer) is deposited in the above-mentioned porous carbon / carbon composite material composited with fullerene by chemical vapor deposition in an atmosphere containing trichloromethylsilane, hydrogen and argon (the volume flow ratio of trichloromethylsilane, hydrogen and argon is 1:2:10) at 1050°C and 25 Pa. The thickness of the silicon carbide interface layer is 150 nm, and a carbon / carbon composite material with a silicon carbide interface layer is obtained.

[0111] ⑤ Preparation of ceramic matrix composite materials: Using liquid polycarbosilane as a reactant, polycarbosilane is reacted with a carbon / carbon composite material having a silicon carbide interface layer by an impregnation cracking method (impregnation / curing / cracking PIP process) to prepare a ceramic matrix composite material; the specific impregnation cracking process includes the following sub-steps: (a) placing the carbon / carbon composite material having a silicon carbide interface layer obtained in step ④ in polycarbosilane, and filling the polycarbosilane into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, the pressure of the pressure impregnation is 1.5MPa, and the pressure impregnation time is 1 h; (b) curing the carbon / carbon composite material having a silicon carbide interface layer treated in step (a) under an argon inert atmosphere and heating conditions of 200°C, so that the polycarbosilane inside the pores can be cross-linked and cured; placing the cross-linked and cured material in a reaction furnace body, sealing, evacuating, and introducing argon inert gas at a flow rate of 1000sccm; setting a program to control the temperature to rise at a rate of 5°C / min to 1080°C and react for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled to fall at a rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) repeating steps (a) to (c) 10 times.

[0112] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the ceramic matrix composite material prepared in this comparative example is 12.3 MPa·m under 1500℃ air environment. 1 / 2 .

[0113] Comparative Example 5

[0114] ① is the same as step ① in Example 1.

[0115] ② is the same as step ② of Example 1.

[0116] ③ is the same as step ③ of Example 1.

[0117] ④ Preparation of ceramic matrix composite materials: Using zirconium carbide-silicon carbide composite ceramic precursor as a reactant, the zirconium carbide-silicon carbide composite ceramic precursor is reacted with a porous carbon / carbon composite material composited with fullerenes by an impregnation and cracking method (impregnation / curing / cracking PIP process) to prepare a ceramic matrix composite material. The specific impregnation and cracking process includes the following sub-steps: (a) placing the porous carbon / carbon composite material composited with fullerenes obtained in step ③ into the zirconium carbide-silicon carbide composite ceramic precursor, and filling the zirconium carbide-silicon carbide composite ceramic precursor into the pores inside the composite material by vacuum impregnation and pressure impregnation; the vacuum impregnation pressure is 150Pa, the vacuum impregnation time is 1h, and then pressure impregnation is performed, and the pressure of the pressure impregnation is 1.5M Pa, the pressure impregnation time is 1h; (b) the porous carbon / carbon composite material containing fullerene treated in step (a) is cured in an argon inert atmosphere and heated at 200°C, so that the zirconium carbide-silicon carbide composite ceramic precursor inside the pores can be cross-linked and cured; the cross-linked and cured material is placed in a reaction furnace body, sealed, evacuated, and argon inert gas is introduced at a flow rate of 1000sccm; the temperature is set to be controlled by program at a heating rate of 5°C / min to 1500°C and the reaction is carried out for 120 minutes; (c) after the cracking reaction in step (b) is completed, the temperature is controlled by program at a cooling rate of 5°C / min. After cooling to room temperature, the introduction of inert gas argon is stopped and the pressure is restored to atmospheric pressure; (d) steps (a) to (c) are repeated 10 times.

[0118] Mechanical properties test under high temperature oxygen environment: The fracture toughness of the ceramic matrix composite material prepared in this comparative example is 6.1MPa·m under 1500℃ air environment. 1 / 2 .

[0119] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0120] 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 toughened ceramic matrix composite material, characterized in that: The method comprises the following steps: (1) Providing a porous carbon / carbon composite material: providing a carbon fiber preform, and then depositing a pyrolytic carbon interface layer on the carbon fiber surface of the carbon fiber preform by chemical vapor deposition to obtain the porous carbon / carbon composite material; (2) subjecting the porous carbon / carbon composite material to a hydrophilic treatment to obtain a hydrophilic porous carbon / carbon composite material; the hydrophilic treatment comprises immersing the porous carbon / carbon composite material in a mixed solution of concentrated sulfuric acid and hydrogen peroxide in a volume ratio of (6-8): (2-4) at 85-98° C. for at least 1 hour, and then immersing the mixed solution in distilled water and drying the mixed solution to obtain a hydrophilic porous carbon / carbon composite material; (3) soaking the hydrophilized porous carbon / carbon composite material in a fullerene aqueous solution and subjecting it to high-temperature treatment to obtain a porous carbon / carbon composite material composited with fullerene; wherein the concentration of the fullerene aqueous solution is 0.3-1.6 mg / mL, the volume percentage of fullerene in the porous carbon / carbon composite material composited with fullerene is 1-4%, and the high-temperature treatment is carried out in an inert atmosphere at a temperature of 400-600°C; (4) using a zirconium carbide-silicon carbide composite ceramic precursor as a reactant, depositing a zirconium carbide-silicon carbide composite interface layer in the porous carbon / carbon composite material containing fullerene by chemical vapor deposition, thereby obtaining a carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer; (5) reacting a zirconium carbide-silicon carbide composite ceramic precursor with the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer by an impregnation pyrolysis method to obtain a toughened ceramic matrix composite material; in steps (4) and (5), the zirconium carbide-silicon carbide composite ceramic precursor is obtained by compounding an oxygen-free zirconium carbide ceramic precursor with polycarbosilane.

2. The preparation method according to claim 1, characterized in that The preparation of the oxygen-free zirconium carbide ceramic precursor is as follows: Tetrakis(dimethylamino)zirconium or tetrakis(diethylamino)zirconium is subjected to an amine exchange reaction with an amine compound, and then subjected to reduced pressure distillation to obtain an oxygen-free zirconium 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, wherein: In step (1), the density of the porous carbon / carbon composite material is 0.7-1.0 g / cm 3 .

4. The preparation method according to claim 1, wherein: After the zirconium carbide-silicon carbide composite ceramic precursor is heated, it is introduced into a chemical vapor deposition furnace through a carrier gas of nitrogen, and simultaneously hydrogen is introduced into the chemical vapor deposition furnace to deposit the zirconium carbide-silicon carbide composite interface layer.

5. The preparation method according to claim 4, characterized in that: The volume flow ratio of nitrogen to hydrogen is 10:(2~5).

6. The preparation method according to claim 4, characterized in that: The flow rate of the nitrogen is 0.5~3L / min.

7. The preparation method according to claim 4, characterized in that: The heating temperature of the zirconium carbide-silicon carbide composite ceramic precursor is 90-150° C.; and / or The temperature for depositing the zirconium carbide-silicon carbide composite interface layer is 1000-1300° C., the time is 1-3 hours, and the pressure in the chemical vapor deposition furnace is 10-150 Pa.

8. The preparation method according to claim 1, wherein: The thickness of the zirconium carbide-silicon carbide composite interface layer is 50-500 nm; and / or The density of the toughened ceramic matrix composite material is 2.3-2.7 g / cm 3 .

9. The preparation method according to claim 1, characterized in that Step (5) includes the following sub-steps: (a) sequentially vacuum impregnating and pressure impregnating the carbon / carbon composite material having a zirconium carbide-silicon carbide composite interface layer using a zirconium carbide-silicon carbide composite ceramic precursor; (b) curing the carbon / carbon composite material having the zirconium carbide-silicon carbide composite interface layer treated in step (a) in an inert atmosphere at 160-320° C., then placing the composite material in a reaction furnace, sealing it, evacuating it, introducing an inert gas, and pyrolyzing it at 1400-1700° C. for 1-360 minutes; (c) After the cracking reaction in step (b) is completed, the temperature is cooled by program control at a cooling rate of 1 to 5°C / min. After cooling to room temperature, the introduction of the inert gas is stopped and the pressure is restored to atmospheric pressure; (d) Repeat steps (a) to (c) at least once.

10. The preparation method according to claim 9, characterized in that: In step (a), the total time of the vacuum impregnation and the pressure impregnation is 60 to 360 minutes.

11. The preparation method according to claim 9, characterized in that: In step (b), the reaction furnace is vacuumed until the pressure inside the reaction furnace is 10-150 Pa.

12. The preparation method according to claim 9, characterized in that: In step (b), the flow rate of the inert gas is 300-3000 sccm.

13. The preparation method according to claim 9, characterized in that: In step (b), the temperature is raised to 1400-1700° C. at a heating rate of 1-10° C. / min.

14. The preparation method according to claim 9, characterized in that: Repeat steps (a) to (c) 1 to 10 times.

15. A strengthened and toughened ceramic matrix composite material obtained by the preparation method according to any one of claims 1 to 14.

16. The toughened ceramic matrix composite material according to claim 15, characterized in that: The fracture toughness of the toughened ceramic matrix composite material in an air environment of 1500°C is not less than 15 MPa·m 1 / 2 .

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