Carbon nanotube fiber toughened ceramic matrix composite and method of making

Abstract

The application relates to a carbon nanotube fiber toughened ceramic matrix composite material and a preparation method thereof. The method comprises the following steps: providing continuous carbon nanotube fibers and carrying out hydroxylation pretreatment; soaking the hydroxylation pretreated carbon nanotube fibers in a graphene oxide aqueous solution to obtain carbon nanotube fibers with a graphene oxide interface layer; carrying out annealing treatment to obtain carbon nanotube fibers with a graphene interface layer; depositing a SiCN interface layer on the surface of the graphene interface layer of the carbon nanotube fibers by using polysilicon carbon nitride as a precursor and through a chemical vapor deposition method to obtain carbon nanotube fibers with a graphene / SiCN composite interface layer; weaving the carbon nanotube fibers into a preform; and reacting ceramic precursors with the preform through an impregnation pyrolysis method to prepare the carbon nanotube fiber toughened ceramic matrix composite material. The ceramic matrix composite material prepared by the application not only has high thermal conductivity, but also has significantly improved mechanical and oxidation resistance performances.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ceramic matrix composite material, and particularly relates to a carbon nanotube fiber toughened ceramic matrix composite material and a preparation method thereof. BACKGROUND

[0002] In the field of aerospace, carbon fiber toughened ceramic matrix composite material has excellent properties such as light weight, high strength, high toughness and high temperature resistance, and is the main candidate material for many thermal structure components, and its application range is becoming more and more extensive. However, the thermal conductivity of carbon fiber and ceramic matrix is lower than 50 W / (m·K), which leads to the thermal conductivity of carbon fiber toughened ceramic matrix composite material being only 10-20 W / (m·K). The application environment of the leading edge and other parts is extremely harsh, and if the thermal conductivity is low, the heat cannot be effectively dissipated, which may exceed the temperature limit of the composite material, causing the overall structure to collapse and the performance to fail, thereby causing irreversible damage.

[0003] As a new type of carbon nanofiber, the room temperature thermal conductivity of carbon nanotube fiber can reach more than 200 W / mK, and the thermal conductivity decreases less at high temperature, and the thermal conductivity performance declines slightly, and the elongation at break is greater than 4%, which is much higher than the elongation at break of carbon fiber (1.5-2.2%). The carbon nanotube fiber exhibits more excellent mechanical properties. The ceramic matrix composite material prepared by impregnation pyrolysis technology with carbon nanotube fiber as toughening phase has a thermal conductivity of 40-150 W / (m·K), and the mechanical properties are also significantly improved. Therefore, the carbon nanotube fiber toughened ceramic matrix composite material is expected to be applied to the leading edge and other parts as the next generation of thermal structure components to quickly dissipate heat and avoid excessive local temperature.

[0004] However, the carbon nanotube fiber toughened ceramic matrix composite material also faces many problems, one of which is that the carbon nanotube fiber has weak oxidation resistance, and its special nano structure leads to weak interfacial bonding strength between the traditional pyrolytic carbon interlayer and the carbon nanotube fiber. Therefore, how to improve the bonding strength between the interlayer and the carbon nanotube fiber and further improve the oxidation resistance of the carbon nanotube fiber is a key problem for the carbon nanotube fiber toughened ceramic matrix composite material to exhibit excellent performance.

[0005] In summary, it is necessary to provide a carbon nanotube fiber toughened ceramic matrix composite material and a preparation method thereof. SUMMARY

[0006] In order to solve one or more technical problems in the prior art, the present application provides a carbon nanotube fiber toughened ceramic matrix composite material and a preparation method thereof. The method improves the bonding strength between the interlayer and the carbon nanotube fiber, and further improves the oxidation resistance of the carbon nanotube fiber toughened ceramic matrix composite material.

[0007] The present application provides a method for preparing a carbon nanotube fiber toughened ceramic matrix composite in a first aspect, and the method comprises the following steps:

[0008] (1) providing continuous carbon nanotube fibers and performing hydroxylization pretreatment to obtain hydroxylization pretreated carbon nanotube fibers;

[0009] (2) preparing an aqueous graphene oxide solution, and then immersing the hydroxylization pretreated carbon nanotube fibers in the aqueous graphene oxide solution to obtain carbon nanotube fibers with a graphene oxide interfacial layer;

[0010] (3) annealing the carbon nanotube fibers with the graphene oxide interfacial layer, and cooling to room temperature to obtain carbon nanotube fibers with a graphene interfacial layer;

[0011] (4) taking polysilicon carbonitride as a precursor, and depositing a SiCN interfacial layer on the surface of the graphene interfacial layer of the carbon nanotube fibers with the graphene interfacial layer by chemical vapor deposition to obtain carbon nanotube fibers with a graphene / SiCN composite interfacial layer;

[0012] (5) weaving the carbon nanotube fibers with the graphene / SiCN composite interfacial layer into a preform, and reacting a ceramic precursor with the preform by an impregnation and pyrolysis method to obtain a carbon nanotube fiber toughened ceramic matrix composite.

[0013] Preferably, the continuous carbon nanotube fibers have a tensile strength of not less than 3 GPa, a single-fiber diameter of 8-15 μm, a continuous length of not less than 10 m, a room-temperature thermal conductivity of not less than 200 W / (m·K), and / or an elongation at break of not less than 4%.

[0014] Preferably, the hydroxylization pretreatment is immersing the continuous carbon nanotube fibers in a mixed solution containing concentrated sulfuric acid and hydrogen peroxide at a volume ratio of (6-8):(2-4) at 75-88°C for 0.5-1.5 h, and then immersing and drying in distilled water to obtain the hydroxylization pretreated carbon nanotube fibers.

[0015] Preferably, in step (2), the concentration of the aqueous graphene oxide solution is 0.6-6.0 mg / mL; in step (2), the immersing time is 10-60 min; and / or the thickness of the graphene oxide interfacial layer is 0.05-0.5 μm.

[0016] Preferably, in step (3), the annealing temperature is 800-1000°C, the annealing time is 1-5 h; and / or the cooling rate is not more than 1°C / min.

[0017] Preferably, in step (4), the polysilicon carbon nitride is heated and introduced into a chemical vapor deposition furnace by a carrier gas nitrogen, and hydrogen and ammonia are introduced into the chemical vapor deposition furnace to deposit the SiCN interface layer; wherein the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:(1-4).

[0018] Preferably, the heating temperature of the polysilicon carbon nitride is 110-150℃; and / or the temperature for depositing the SiCN interface layer is 1200-1500℃, the time is 3.5-5h, and the pressure in the chemical vapor deposition furnace is 10-150Pa.

[0019] Preferably, the thickness of the SiCN interface layer is 0.3-1.0μm.

[0020] Preferably, the ceramic precursor is one or more of a zirconium silicon precursor, a silicon carbide precursor, a zirconium carbide precursor, and a hafnium carbide precursor; and / or the density of the carbon nanotube fiber toughened ceramic matrix composite material is 2.0-2.5g / cm 3 .

[0021] In a second aspect, the present application provides a carbon nanotube fiber toughened ceramic matrix composite material prepared by the preparation method described in the first aspect of the present application.

[0022] Compared with the prior art, the present application has at least the following beneficial effects:

[0023] (1) The present application selects carbon nanotube fibers as toughening phases, and a graphene interface layer is prepared on the surface of the fibers by a self-assembly method. Both carbon nanotubes and graphene are sp2 hybridized nanocarbon materials, and by means of high-temperature annealing technology, they can form moderate π-π interaction forces, effectively improving the bonding strength of the carbon nanotube fibers and the graphene interface layer, and helping to improve the mechanical properties of the composite material.

[0024] (2) The present application uses chemical vapor deposition technology to prepare a SiCN interface layer on the surface of the graphene interface layer by using a polymer polysilicon carbon nitride as an organic precursor, and finally obtains a graphene / SiCN composite interface layer. Compared with traditional pyrolytic carbon interface layers and SiC interface layers, the present application finds that introducing a SiCN interface layer on the surface of the graphene interface layer has more excellent oxidation resistance and ablation resistance than introducing a pyrolytic carbon interface layer or a SiC interface layer. At the same time, the method of forming the SiCN interface layer in the present application can effectively avoid the structural and performance damage caused by the corrosion of hydrogen chloride gas to the carbon nanotube fibers, and effectively improve the oxidation resistance and high-temperature mechanical properties of the ceramic matrix composite material.

[0025] (3) The application effectively solves the problems of poor bonding strength between the interface layer and the carbon nanotube fiber and damage to the carbon nanotube fiber caused by hydrogen chloride in the traditional deposition method. The carbon nanotube fiber toughened ceramic matrix composite prepared by the application has high thermal conductivity, and the mechanical and oxidation resistance properties are significantly improved, and has the advantages of high toughness and strong oxidation resistance, and excellent mechanical properties in a high-temperature aerobic environment. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described below in conjunction with embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0027] The present application provides, in a first aspect, a method for preparing a carbon nanotube fiber toughened ceramic matrix composite, the method comprising the following steps:

[0028] (1) providing continuous carbon nanotube fibers and performing hydroxylization pretreatment to obtain hydroxylization pretreated carbon nanotube fibers; the source of the continuous carbon nanotube fibers is not specifically limited in the present application, and can be a product purchased directly or a product prepared by an existing method;

[0029] (2) preparing an aqueous graphene oxide solution, and then immersing the hydroxylization pretreated carbon nanotube fibers in the aqueous graphene oxide solution to obtain carbon nanotube fibers with an interface layer of graphene oxide; in the present application, an aqueous graphene oxide solution with a certain concentration is prepared, and an interface layer of graphene oxide is self-assembled on the surface of the carbon nanotube fibers by an immersion-adsorption method; in the present application, for example, after immersion in the aqueous graphene oxide solution, the carbon nanotube fibers with the interface layer of graphene oxide are obtained by separation; the separation can be, for example, pulling the immersed carbon nanotube fibers out of the aqueous graphene oxide solution to obtain the carbon nanotube fibers with the interface layer of graphene oxide;

[0030] (3) annealing the carbon nanotube fibers with the interface layer of graphene oxide, and cooling to room temperature (room temperature 15-35℃) to obtain carbon nanotube fibers with an interface layer of graphene; in the present application, the bonding strength between the carbon nanotube fibers and the interface layer of graphene can be improved by high-temperature annealing technology;

[0031] (4) taking polysilicon carbon nitride alkane (polymer polysilicon carbon nitride alkane) as a precursor, depositing SiCN interface layer on the surface of the graphene interface layer of the carbon nanotube fiber with graphene interface layer through chemical vapor deposition method, to obtain carbon nanotube fiber with graphene / SiCN composite interface layer; that is, taking polymer polysilicon carbon nitride alkane as an organic precursor, using chemical vapor deposition process to prepare SiCN interface layer on the surface of the graphene interface layer, and finally obtaining graphene / SiCN composite interface layer; the source of polysilicon carbon nitride alkane is not specifically limited in the application, which can be a product purchased directly or a product prepared by an existing method; in the application, the polysilicon carbon nitride alkane is liquid polysilicon carbon nitride alkane; specifically, for example, the carbon nanotube fiber with graphene interface layer is placed in a chemical vapor deposition furnace, the heating temperature of polysilicon carbon nitride alkane is controlled, nitrogen, hydrogen and ammonia are introduced in a vacuum high-temperature state, and after a certain period of time, the SiCN interface layer is formed on the surface of the carbon nanotube fiber;

[0032] (5) weaving the carbon nanotube fiber with the graphene / SiCN composite interface layer into a preform, reacting a ceramic precursor with the preform through an impregnation-pyrolysis method (PIP process of impregnation / curing / pyrolysis) to obtain a carbon nanotube fiber toughened ceramic matrix composite, in other words, using the ceramic precursor as a reactant to prepare the carbon nanotube fiber toughened ceramic matrix composite through the precursor impregnation-pyrolysis method; in the present application, the weaving method may be one or more of piercing, sewing or needling; in the present application, the ceramic precursor is one or more of a zirconium-silicon precursor, a silicon carbide precursor, a zirconium carbide precursor and a hafnium carbide precursor, and is preferably a zirconium-silicon precursor; in the present application, the zirconium-silicon precursor is a polymer mainly containing zirconium and silicon, which can be converted into ZrC / SiC ceramic through high-temperature pyrolysis and is a known product in the prior art, which can be purchased from the Chinese Academy of Sciences Institute of Chemistry or synthesized according to the prior art; in the PIP process of impregnation / curing / pyrolysis, the zirconium-silicon precursor solution is used as the impregnation liquid; the zirconium-silicon precursor solution uses the zirconium-silicon precursor as a solute and dimethylbenzene as a solvent, and the solid content of the zirconium-silicon precursor solution may be 50-70 wt%; in the present application, preferably, in the PIP process of impregnation / curing / pyrolysis, the impregnation is first vacuum impregnation at a pressure of 20-200 Pa, and then pressure impregnation at a pressure of 1-2 MPa, the vacuum impregnation time is 1-2 h each time, the pressure impregnation time is 1-2 h each time, the curing temperature is 200-300 DEG C, the curing time is 1-3 h each time, the curing is carried out in an argon atmosphere, the pyrolysis temperature is 1400-1600 DEG C, the pyrolysis holding time is 1-4 h each time, and the pyrolysis is carried out in an argon atmosphere, and the present application does not specifically limit the number of times of repeating impregnation, curing and pyrolysis until the density of the ceramic matrix composite reaches 2.0-2.5 g / cm 3 In the present application, all the pressures refer to absolute pressures.

[0033] The present application fully utilizes the high thermal conductivity of the carbon nanotube fiber, deposits graphene on the fiber surface through soaking-adsorption, further improves the bonding strength of graphene and the carbon nanotube fiber by means of rapid high-temperature annealing, and effectively solves the problems of poor bonding strength of the interface layer and the carbon nanotube fiber and damage of the carbon nanotube fiber caused by hydrogen chloride produced in the traditional deposition method by using a suitable chemical vapor deposition process to construct a SiCN interface layer, thereby effectively improving the oxidation resistance and high-temperature mechanical properties of the ceramic matrix composite.

[0034] The application adopts chemical vapor deposition technology, uses polymer polysilicon carbon nitride as an organic precursor, prepares a SiCN interface layer on the surface of a graphene interface layer, and finally obtains a graphene / SiCN composite interface layer. Compared with traditional pyrolytic carbon interface layers and SiC interface layers, the application finds that introducing a SiCN interface layer on the surface of a graphene interface layer has more excellent oxidation resistance and ablation resistance than introducing a pyrolytic carbon interface layer or a SiC interface layer. The carbon nanotube fiber toughened ceramic matrix composite prepared by the application has high thermal conductivity, and the mechanical and oxidation resistance properties are significantly improved, has the advantages of high toughness and strong oxidation resistance, and has excellent mechanical properties in a high-temperature oxygen environment.

[0035] According to some preferred embodiments, the continuous carbon nanotube fiber has a tensile strength of not less than 3 GPa, a single-fiber diameter of 8-15 μm, a continuous length of not less than 10 m, a room-temperature thermal conductivity of not less than 200 W / (m·K), and / or an elongation at break of not less than 4%; the continuous carbon nanotube fiber has excellent toughness.

[0036] According to some preferred embodiments, the hydroxylation pretreatment is soaking the continuous carbon nanotube fiber in a mixed solution containing concentrated sulfuric acid and hydrogen peroxide at a volume ratio of (6-8):(2-4) (for example, 6:4, 7:3 or 8:2) at 75-88 ℃ (for example, 75 ℃, 80 ℃, 85 ℃ or 88 ℃) for 0.5-1.5 h (for example, 0.5, 1 or 1.5 h), then soaking in distilled water for 0.5-2 h and drying to obtain the hydroxylated pretreated carbon nanotube fiber; in the application, the concentrated sulfuric acid is, for example, concentrated sulfuric acid with a mass fraction of 98 wt% (abbreviated as 98% concentrated sulfuric acid), and the hydrogen peroxide is, for example, hydrogen peroxide with a mass fraction of 30 wt% (abbreviated as 30% hydrogen peroxide); in the application, the soaking in distilled water is performed at room temperature (for example, room temperature of 15-35 ℃); the application does not specifically limit the drying conditions, which are conventional techniques in the art.

[0037] According to some specific embodiments, the hydroxylation pretreatment is soaking the dried continuous carbon nanotube fiber in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide at a volume ratio of 7:3, and placing it in a 75-88 ℃ oil bath for heat preservation and standing for 0.5-1.5 h. After the end, it is taken out and soaked in distilled water, and then dried before use, at which time a large number of hydrophilic hydroxyl groups are formed on the surface of the carbon nanotube fiber; in the application, by controlling the heat preservation and standing time in the mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide at a volume ratio of 7:3, the content of the hydrophilic hydroxyl groups can be regulated.

[0038] According to some preferred embodiments, in step (2), the concentration of the aqueous graphene oxide solution is 0.6-6.0 mg / mL (for example, 0.6, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5 or 6 mg / mL), i.e. the concentration of graphene oxide in the aqueous graphene oxide solution is 0.6-6.0 mg / mL; the graphene oxide used in the present application is not particularly limited and can be graphene oxide obtained by strong oxidation of graphite flakes or graphene oxide obtained by other methods; in the present application, it is preferred that the concentration of the aqueous graphene oxide solution is 0.6-6.0 mg / mL, so as to ensure that the graphene interface layer obtained finally is of high quality and can play a good interface layer role; it has been found by the present application that if the mass concentration of the aqueous graphene oxide solution is higher than 6.0 mg / mL, the graphene oxide is too aggregated and the self-assembly layer effect is poor, so that a high-quality graphene oxide interface layer cannot be obtained, and further a high-quality graphene interface layer cannot be formed; if the mass concentration of the aqueous graphene oxide solution is lower than 0.6 mg / mL, the graphene oxide in the solution is too sparse, and even after a long time, the surface of the carbon nanotube fiber cannot be completely covered, so that the graphene oxide cannot play a good interface layer role.

[0039] According to some preferred embodiments, in step (2), the soaking time is 10-60 min (for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 min); and / or the thickness of the graphene oxide interface layer is 0.05-0.5 μm (for example, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4 or 0.5 μm); in the present application, the thickness of the interface layer can be regulated by regulating the concentration of graphene oxide and the standing time (soaking time).

[0040] According to some specific embodiments, step (2) is: by placing the carbon nanotube fiber with a large number of hydrophilic hydroxyl groups formed on the surface in an aqueous graphene oxide solution with a concentration of 0.6-6.0 mg / mL and standing (soaking) for 10-60 min, the solution is pulled out, and a graphene oxide interface layer can be self-assembled on the surface of the fiber, and the thickness of the interface layer is 0.05-0.5 μm.

[0041] According to some preferred embodiments, in step (3): the temperature of the annealing treatment is 800-1000℃ (for example, 800℃, 850℃, 900℃, 950℃ or 1000℃), the time of the annealing treatment is 1-5 h (for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5 h); and / or the cooling rate is not higher than 1℃ / min; in the present application, the annealing treatment is carried out in an inert atmosphere.

[0042] In the present application, by the high-temperature annealing technology, the treatment temperature is 800-1000℃, and the cooling rate is ≤1℃ / min, on the one hand, the graphene oxide can be converted into graphene, and on the other hand, the carbon nanotube and the graphene form the π-π interaction force, so as to effectively improve the bonding strength of the carbon nanotube fiber and the graphene interface layer; it is found that in the annealing treatment, it is very important to control the cooling rate ≤1℃ / min, and the slow cooling mode has two advantages, on the one hand, the graphene oxide can be converted into graphene, and on the other hand, the carbon nanotube and the graphene form the moderate π-π interaction force, so as to effectively improve the bonding strength of the carbon nanotube fiber and the graphene interface layer; if the cooling rate is higher than 1℃ / min, the small molecule gas such as CO and CO2 formed by the splitting of the graphene oxide may escape quickly, which will lead to the formation of larger pores between the layers, the stacking effect of the graphene is poor, and the performance of the graphene interface layer formed will be obviously affected.

[0043] According to some specific embodiments, step (3) is: placing the carbon nanotube fiber with the graphene oxide interface layer into a high-temperature furnace body, extracting vacuum to 20-50Pa, and continuously introducing nitrogen or argon, setting the annealing temperature to 800-1000℃, setting the holding time to 1-5h, and setting the cooling rate to ≤1℃ / min.

[0044] According to some preferred embodiments, the polysilicon carbon nitride alkane is heated and introduced into a chemical vapor deposition furnace through a carrier gas nitrogen, and hydrogen and ammonia are introduced into the chemical vapor deposition furnace to deposit the SiCN interface layer; wherein the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:(1-4) (for example, 10:5:1, 10:5:2, 10:5:3 or 10:5:4).

[0045] According to some preferred embodiments, the heating temperature of the polysilicon carbon nitride alkane is 110-150℃ (for example, 110℃, 120℃, 130℃, 140℃ or 150℃); and / or the temperature for depositing the SiCN interface layer is 1200-1500℃ (for example, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃ or 1500℃), the time is 3.5-5h (for example, 3.5h, 4h, 4.5h or 5h), and the pressure in the chemical vapor deposition furnace is 10-150Pa (for example, 10Pa, 20Pa, 30Pa, 40Pa, 50Pa, 60Pa, 70Pa, 80Pa, 90Pa, 100Pa, 110Pa, 120Pa, 130Pa, 140Pa or 150Pa).

[0046] The present application is prepared by a large number of creative experiments, and it is found that when the polysilicon carbon nitride is used as a reactant to prepare the SiCN interface layer by chemical vapor deposition, the chemical vapor deposition temperature in the reaction furnace is preferably controlled to be 1200-1500 DEG C, and the flow ratio of nitrogen, hydrogen and ammonia is controlled to be 10:5:(1-4), so that the ceramic matrix composite material with strong oxidation resistance and high mechanical properties in the high-temperature aerobic environment can be obtained. It is found that if the chemical vapor deposition temperature is higher than 1500 DEG C, SiCN will be decomposed by heat to form Si3N4 and other substances, and the oxidation resistance will be reduced. If the chemical vapor deposition temperature is lower than 1200 DEG C, the SiCN precursor will not be fully cracked, and a stable SiCN interface layer will not be formed. If the flow ratio of nitrogen, hydrogen and ammonia is higher than 10:5:4, a considerable proportion of SiCN will be converted into Si3N4. If the flow ratio of nitrogen, hydrogen and ammonia is lower than 10:5:1, SiCN will be converted into SiC, and the oxidation resistance of the ceramic matrix composite material will be affected.

[0047] According to some specific embodiments, step (4) is: placing the carbon nanotube fiber with a graphene interface layer in a chemical vapor deposition furnace (reaction furnace), vacuumizing, the pressure in the reaction furnace is 10-150 Pa, at the same time, the temperature in the reaction furnace is controlled to be 1200-1500 DEG C, and the temperature is kept for 10 min to ensure that the temperature in the furnace body is uniform. Next, the heated polysilicon carbon nitride is carried into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas, and the heating temperature of the polysilicon carbon nitride is controlled to be 110-150 DEG C. While the carrier gas nitrogen continuously carries the polysilicon carbon nitride into the cavity, hydrogen and ammonia are also introduced into the furnace cavity. The flow ratio of nitrogen, hydrogen and ammonia is 10:5:1-4, and the flow of the carrier gas nitrogen is controlled to be 0.1-2 L / min. After the reaction furnace is kept for 3.5-5 h, the SiCN interface layer is formed on the surface of the carbon nanotube fiber, and the thickness is 0.3-1.0 μm. Then, the temperature is lowered, and the heating of the polysilicon carbon nitride and the introduction of ammonia and hydrogen are stopped in turn. The nitrogen is kept flowing during the whole cooling process until the temperature is lowered to room temperature, and the sample is taken out. In the present application, the room temperature is, for example, 15-35 DEG C.

[0048] According to some preferred embodiments, the thickness of the SiCN interface layer is 0.3-1.0 μm (for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 μm).

[0049] According to some preferred embodiments, the ceramic precursor is one or more of zirconium silicon precursor, silicon carbide precursor, zirconium carbide precursor, hafnium carbide precursor; and / or the density of the carbon nanotube fiber toughened ceramic matrix composite material is 2.0-2.5 g / cm 3The application is preferably to prepare the carbon nanotube fiber toughened ceramic matrix composite material by precursor impregnation pyrolysis method with zirconium silicon precursor as the reactant, and preferably to prepare the carbon nanotube fiber toughened ceramic matrix composite material with a density of 2.0-2.5 g / cm 3 The carbon nanotube fiber toughened ceramic matrix composite material prepared by the application has not only high thermal conductivity, but also significantly improved mechanical and oxidation resistance.

[0050] The application provides in a second aspect the carbon nanotube fiber toughened ceramic matrix composite material prepared by the preparation method in the first aspect.

[0051] The application will be further described below by way of examples, but the protection scope of the application is not limited to the examples. The application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the application without departing from the spirit and essence of the application, and the corresponding changes and modifications shall all belong to the protection scope of the claims of the application. The experimental methods used in the following examples are conventional methods without special instructions. The materials, reagents and the like used in the following examples can be obtained from commercial channels or prepared by existing methods without special instructions.

[0052] Example 1

[0053] ① Provide continuous carbon nanotube fibers and perform hydroxylation pretreatment to obtain hydroxylation pretreated carbon nanotube fibers; the continuous carbon nanotube fibers have a tensile strength of 4 GPa, a single fiber diameter of 10 μm, a continuous length of 15 m, a room temperature thermal conductivity of 270 W / mK, and an elongation at break of 4.8%; the hydroxylation pretreatment is as follows: the dried continuous carbon nanotube fibers are soaked in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 7:3, and are placed in an 80°C oil bath for 1.0 h. After the end, they are taken out and soaked in distilled water at room temperature for 0.5 h, and finally dried to obtain the hydroxylation pretreated carbon nanotube fibers.

[0054] ② Prepare a graphene oxide interface layer: prepare a graphene oxide aqueous solution with a concentration of 0.6 mg / mL, place the hydroxylation pretreated carbon nanotube fibers in the graphene oxide aqueous solution and stand for 30 min, and then take out the solution to obtain the carbon nanotube fibers with the graphene oxide interface layer, and the thickness of the graphene oxide interface layer is 0.05 μm.

[0055] ③ High-temperature annealing technology for preparing graphene interface layer: the carbon nanotube fiber with graphene interface layer prepared above is placed in a high-temperature furnace, vacuum is extracted to 20 Pa, argon is continuously introduced, the annealing temperature is set to 1000℃, the holding time (annealing time) is set to 2h, and after annealing, the temperature is reduced to room temperature at a rate of 0.5℃ / min to obtain a carbon nanotube fiber with a graphene interface layer.

[0056] ④ Preparation of SiCN interface layer: the carbon nanotube fiber with graphene interface layer is placed in a chemical vapor deposition furnace, vacuum is extracted, the pressure in the reaction furnace is 25 Pa, the temperature in the reaction furnace is controlled at 1300℃, and the temperature is kept for 10 min to ensure that the temperature in the furnace is uniform. Next, the heated polysilicon carbon nitride alkane is brought into the chemical vapor deposition furnace cavity by using nitrogen as the carrier gas, and the heating temperature of the polysilicon carbon nitride alkane is controlled at 120℃. While continuously carrying the polysilicon carbon nitride alkane into the cavity by using the carrier gas, hydrogen and ammonia are introduced into the furnace cavity, and the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:2, wherein the nitrogen flow is controlled at 2L / min. After the reaction furnace is kept at 1300℃ for 4h, a SiCN interface layer is formed on the surface of the graphene interface layer of the carbon nanotube fiber, and the thickness of the SiCN interface layer is 1.0μm. Then, the temperature is reduced, and the heating of the polysilicon carbon nitride alkane and the introduction of ammonia and hydrogen are stopped in turn. Nitrogen is continuously introduced during the whole cooling process until the temperature is reduced to room temperature. The sample is taken out to obtain a carbon nanotube fiber with a graphene / SiCN composite interface layer.

[0057] ⑤ The carbon nanotube fiber with graphene / SiCN composite interface layer prepared above is woven to obtain a piercing preform. A zirconium-silicon precursor solution is reacted with the piercing preform by a dip-pyrolysis method (PIP process of dipping / solidifying / pyrolysis) to prepare a carbon nanotube fiber toughened ceramic matrix composite material with a density of 2.1g / cm 3

[0058] ​High-temperature mechanical property test in aerobic environment: the tensile strength of the carbon nanotube fiber toughened ceramic matrix composite prepared in this embodiment is 278 MPa at 1500℃ in air environment. The thermal conductivity of the carbon nanotube fiber toughened ceramic matrix composite prepared in this embodiment is 53 W / (m·K) at room temperature.

[0059] Example 2

[0060] ① Provide continuous carbon nanotube fibers and perform hydroxylation pretreatment to obtain hydroxylated pretreated carbon nanotube fibers; the tensile strength of the continuous carbon nanotube fibers is 4 GPa, the single fiber diameter is 10 μm, the continuous length is 15 m, the room temperature thermal conductivity is 270 W / mK, and the elongation at break is 4.8%; the hydroxylation pretreatment is: soaking the above dried continuous carbon nanotube fibers in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 7:3, and placing in an 80℃ oil bath for 1.0 h. After the end, take out and soak in distilled water at room temperature for 0.5 h, and finally dry to obtain hydroxylated pretreated carbon nanotube fibers.

[0061] ②Preparation of graphene oxide interface layer: prepare an aqueous solution of graphene oxide with a concentration of 2.8 mg / mL, place the hydroxylated pretreated carbon nanotube fibers in the aqueous solution of graphene oxide and stand for 30 min, and then pull out the solution to obtain carbon nanotube fibers with a graphene oxide interface layer, and the thickness of the graphene oxide interface layer is 0.23 μm.

[0062] ③ High-temperature annealing technology to prepare graphene interface layer: place the carbon nanotube fibers with graphene oxide interface layer in a high-temperature furnace, extract vacuum to 20 Pa, and continuously introduce argon, set the annealing temperature to 1000℃, and set the holding time (annealing time) to 2 h, after annealing, cool to room temperature at a cooling rate of 0.5℃ / min, to obtain carbon nanotube fibers with graphene interface layer.

[0063] (4) Preparing the SiCN interface layer: the carbon nanotube fiber with the graphene interface layer is placed in a chemical vapor deposition furnace, vacuum is extracted, the pressure in the reaction furnace is 25 Pa, the temperature in the reaction furnace is controlled at 1300 °C, and the temperature is kept for 10 min to ensure that the temperature in the furnace body is uniform. Next, the heated polysilicon carbon nitride is carried into the chemical vapor deposition furnace cavity by nitrogen as a carrier gas, and the heating temperature of the polysilicon carbon nitride is controlled at 120 °C. While continuously carrying the polysilicon carbon nitride into the cavity by the carrier gas, hydrogen and ammonia are introduced into the furnace cavity, and the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:2, wherein the nitrogen flow is controlled at 2 L / min. After the reaction furnace is kept at 1300 °C for 4 h, a SiCN interface layer is formed on the surface of the graphene interface layer of the carbon nanotube fiber, and the thickness of the SiCN interface layer is 1.0 μm. Then, the temperature is lowered, and the heating of the polysilicon carbon nitride and the introduction of ammonia and hydrogen are stopped in turn. Nitrogen is continuously introduced during the whole cooling process until the temperature is lowered to room temperature. The sample is taken out to obtain a carbon nanotube fiber with a graphene / SiCN composite interface layer.

[0064] (5) The carbon nanotube fiber with the graphene / SiCN composite interface layer is woven to obtain a piercing preform. A zirconium-silicon precursor solution is reacted with the piercing preform by an impregnation-pyrolysis method (PIP process of impregnation / curing / pyrolysis) to prepare a carbon nanotube fiber toughened ceramic matrix composite material with a density of 2.1 g / cm 3

[0065] Mechanical property test under high-temperature aerobic environment: The tensile strength of the carbon nanotube fiber toughened ceramic matrix composite material prepared in this embodiment is 309 MPa under 1500 °C air environment.

[0066] Example 3

[0067] ​① providing continuous carbon nanotube fibers and performing hydroxylated pretreatment to obtain hydroxylated pretreated carbon nanotube fibers; the continuous carbon nanotube fibers have a tensile strength of 4 GPa, a single fiber diameter of 10 μm, a continuous length of 15 m, a room temperature thermal conductivity of 270 W / mK, and an elongation at break of 4.8%; the hydroxylated pretreatment is as follows: the dried continuous carbon nanotube fibers are soaked in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 7:3, and are kept in an 80°C oil bath for 1.0 h. After the end, the sample is taken out and soaked in distilled water at room temperature for 0.5 h, and finally dried to obtain the hydroxylated pretreated carbon nanotube fibers.

[0068] ② preparing a graphene oxide interface layer: preparing an aqueous graphene oxide solution with a concentration of 0.6 mg / mL, placing the hydroxylated pretreated carbon nanotube fibers in the aqueous graphene oxide solution and keeping for 30 min, and taking out the solution to obtain carbon nanotube fibers with a graphene oxide interface layer, the thickness of the graphene oxide interface layer being 0.05 μm.

[0069] ③ preparing a graphene interface layer by high-temperature annealing technology: placing the carbon nanotube fibers with the graphene oxide interface layer in a high-temperature furnace, extracting vacuum to 20 Pa, continuously introducing argon, setting the annealing temperature to 1000°C, setting the holding time (annealing time) to 2 h, and reducing to room temperature at a cooling rate of 0.1°C / min after the completion of annealing to obtain carbon nanotube fibers with a graphene interface layer.

[0070] ④ preparing a SiCN interface layer: placing the carbon nanotube fibers with the graphene interface layer in a chemical vapor deposition furnace, extracting vacuum, controlling the pressure in the reaction furnace to 25 Pa, and keeping the temperature in the reaction furnace at 1300°C for 10 min to ensure that the temperature in the furnace is uniform. Next, heated polysilicon carbon nitride is carried into the chemical vapor deposition furnace cavity by nitrogen gas as a carrier gas, the heating temperature of the polysilicon carbon nitride is controlled at 120°C, while the carrier gas continuously carries the polysilicon carbon nitride into the cavity, hydrogen and ammonia are introduced into the furnace cavity, the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:2, and the nitrogen flow is controlled at 2 L / min. After the reaction furnace is kept at 1300°C for 4 h, a SiCN interface layer is formed on the surface of the graphene interface layer of the carbon nanotube fibers, the thickness of the SiCN interface layer is 1.0 μm. Then, the heating of the polysilicon carbon nitride and the introduction of ammonia and hydrogen are stopped in turn, and nitrogen is continuously introduced during the whole cooling process until the sample is taken out and cooled to room temperature to obtain carbon nanotube fibers with a graphene / SiCN composite interface layer.

[0071] ⑤weaving the carbon nanotube fiber with graphene / SiCN composite interface layer to obtain a piercing preform, and reacting a zirconium-silicon precursor solution with the piercing preform by a dipping-pyrolysis method (PIP process of dipping / solidifying / pyrolysis) to obtain a carbon nanotube fiber toughened ceramic matrix composite material with a density of 2.1 g / cm 3 The zirconium-silicon precursor solution has a zirconium-silicon precursor as solute and xylene as solvent, and the solid content of the zirconium-silicon precursor solution is 60 wt%. In each dipping / solidifying / pyrolysis cycle, the dipping is first vacuum dipping at a pressure of 200 Pa, and then pressure dipping at a pressure of 1.5 MPa. The time for each vacuum dipping is 1.5 h, and the time for each pressure dipping is 1.5 h. The solidifying is at a temperature of 200 ℃, and the time for each solidifying is 1 h. The solidifying is performed in an argon atmosphere. The pyrolysis is at a temperature of 1400 ℃, and the time for each pyrolysis is 2 h. The pyrolysis is performed in an argon atmosphere.

[0072] High-temperature mechanical property test in an oxygen environment: The tensile strength of the carbon nanotube fiber toughened ceramic matrix composite material prepared in this embodiment is 295 MPa at 1500 ℃ in an air environment.

[0073] Example 4

[0074] ①Provide continuous carbon nanotube fiber and perform hydroxylation pretreatment to obtain hydroxylation pretreated carbon nanotube fiber; the tensile strength of the continuous carbon nanotube fiber is 4 GPa, the single fiber diameter is 10 μm, the continuous length is 15 m, the room temperature thermal conductivity is 270 W / mK, and the elongation at break is 4.8%; the hydroxylation pretreatment is: soaking the above dried continuous carbon nanotube fiber in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 7:3, and placing in an 80 ℃ oil bath for 1.0 h. After the end, take out and soak in distilled water at room temperature for 0.5 h, and finally dry to obtain the hydroxylation pretreated carbon nanotube fiber.

[0075] ②Preparation of graphene oxide interface layer: prepare an aqueous graphene oxide solution with a concentration of 0.6 mg / mL, place the hydroxylation pretreated carbon nanotube fiber in the aqueous graphene oxide solution and stand for 30 min, and then lift out the solution to obtain carbon nanotube fiber with graphene oxide interface layer, and the thickness of the graphene oxide interface layer is 0.05 μm.

[0076] ③Preparation of graphene interface layer by high-temperature annealing technology: place the carbon nanotube fiber with graphene oxide interface layer in a high-temperature furnace, extract vacuum to 20 Pa, and continuously introduce argon. Set the annealing temperature to 1000 ℃, and the holding time (annealing time) to 2 h. After annealing, cool to room temperature at a cooling rate of 0.5 ℃ / min to obtain carbon nanotube fiber with graphene interface layer.

[0077] (4) Preparing the SiCN interface layer: the carbon nanotube fiber with the graphene interface layer is placed in a chemical vapor deposition furnace, vacuum is extracted, the pressure in the reaction furnace is 25 Pa, the temperature in the reaction furnace is controlled at 1300 ℃, and the temperature is kept for 10 min to ensure that the temperature in the furnace body reaches a uniform state. Next, the heated polysilicon carbon nitride is carried into the cavity by nitrogen as a carrier gas, and the heating temperature of the polysilicon carbon nitride is controlled at 120 ℃. While continuously carrying the polysilicon carbon nitride into the cavity by the carrier gas, hydrogen and ammonia are introduced into the furnace cavity, and the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:2, wherein the nitrogen flow is controlled at 1 L / min. After the reaction furnace is kept at 1300 ℃ for 4 h, a SiCN interface layer is formed on the surface of the graphene interface layer of the carbon nanotube fiber, and the thickness of the SiCN interface layer is 0.6 μm. Then, the temperature is lowered, and the heating of the polysilicon carbon nitride and the introduction of ammonia and hydrogen are stopped in turn. Nitrogen is continuously introduced during the whole cooling process until the temperature is lowered to room temperature. The sample is taken out to obtain a carbon nanotube fiber with a graphene / SiCN composite interface layer.

[0078] (5) The carbon nanotube fiber with the graphene / SiCN composite interface layer is woven to obtain a piercing preform. A zirconium-silicon precursor solution is reacted with the piercing preform by a dip and pyrolysis method (PIP process of dip / solidification / pyrolysis) to prepare a carbon nanotube fiber toughened ceramic matrix composite material with a density of 2.1 g / cm 3

[0079] Mechanical property test under high temperature and aerobic environment: the tensile strength of the carbon nanotube fiber toughened ceramic matrix composite material prepared in this embodiment is 253 MPa at 1500 ℃ in air environment.

[0080] ​From the above examples 1-4, compared with example 1, in example 2, the concentration of graphene oxide is increased from 0.6 mg / mL to 2.8 mg / mL when preparing the graphene oxide interface layer, which makes the thickness of the graphene oxide interface layer increase from 0.05 μm to 0.23 μm, which makes the mechanical properties of the final ceramic matrix composite material significantly improved, and the tensile strength under 1500℃ air environment is increased from 278 MPa to 309 MPa. Compared with example 1, in example 3, the high temperature annealing rate is reduced from 0.5℃ / min to 0.1℃ / min when preparing the graphene interface layer, which makes the graphene interface layer stacking effect better, further improves the bonding strength between the carbon nanotube fiber and the graphene interface layer, which makes the mechanical properties of the final ceramic matrix composite material significantly improved, and the tensile strength under 1500℃ air environment is increased from 278 MPa to 295 MPa. Compared with example 1, in example 4, the nitrogen flow is reduced from 2L / min to 1L / min when preparing the SiCN interface layer, which makes the thickness of the SiCN interface layer decrease from 1.0 μm to 0.6 μm, which leads to the decrease of the oxidation resistance of the composite material, which makes the mechanical properties of the final ceramic matrix composite material also significantly decreased, and the tensile strength under 1500℃ air environment is reduced from 278 MPa to 253 MPa.

[0081] Examples 5-11

[0082] The specific process parameters of examples 5-11 and the performance indicators of the final ceramic matrix composite material are shown in table 1, and the other preparation processes are the same as example 1.

[0083]

[0084]

[0085] As can be seen from Table 1, compared with Example 1, in Example 5, the concentration of graphene oxide is reduced from 0.6 mg / mL to 0.5 mg / mL when preparing the graphene oxide interface layer, so that the thickness of the graphene oxide interface layer is reduced from 0.05 μm to 0.03 μm, which may cause the graphene interface layer in some areas not to be completely covered, so that the mechanical properties of the final ceramic matrix composite material are reduced, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 186 MPa. Compared with Example 1, in Example 6, the concentration of graphene oxide is increased from 0.6 mg / mL to 8 mg / mL when preparing the graphene oxide interface layer, although the thickness of the graphene oxide interface layer is increased from 0.05 μm to 0.65 μm, but the graphene oxide is too aggregated, the self-assembly layering effect is poor, and high-quality and complete graphene oxide interface layer cannot be obtained, which makes the mechanical properties of the final ceramic matrix composite material decrease, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 233 MPa. Compared with Example 1, in Example 7, the annealing rate at high temperature is increased from 0.5°C / min to 2°C / min when preparing the graphene interface layer, so that the layering effect of the graphene interface layer is poor, and the bonding strength between the carbon nanotube fiber and the graphene interface layer is extremely weak, which makes the mechanical properties of the final ceramic matrix composite material decrease, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 143 MPa. Compared with Example 1, in Example 8, the deposition temperature is reduced from 1300°C to 1000°C when preparing the SiCN interface layer, which causes the SiCN precursor to be insufficiently cracked, and a stable SiCN interface layer is not formed, so that the mechanical properties of the final ceramic matrix composite material are poor, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 208 MPa. Compared with Example 1, in Example 9, the deposition temperature is increased from 1300°C to 1600°C when preparing the SiCN interface layer, which causes the SiCN to be decomposed to form Si3N4 and other substances, and the oxidation resistance is reduced, so that the mechanical properties of the final ceramic matrix composite material are poor, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 221 MPa. Compared with Example 1, in Example 10, the volume flow ratio of nitrogen, hydrogen and ammonia is reduced from 10:5:2 to 10:5:0.5 when preparing the SiCN interface layer, which causes the SiCN to be converted into SiC, and affects the high-temperature mechanical properties of the composite material, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 243 MPa. Compared with Example 1, in Example 11, the flow ratio of nitrogen, hydrogen and ammonia is increased from 10:5:2 to 10:5:5 when preparing the SiCN interface layer, which causes the SiCN to be converted into Si3N4, and also affects the high-temperature mechanical properties of the composite material, and the tensile strength under 1500°C air environment is reduced from 278 MPa to 196 MPa.

[0086] Comparative Example 1

[0087] ① providing continuous carbon nanotube fiber and performing hydroxylated pretreatment to obtain hydroxylated pretreated carbon nanotube fiber; the continuous carbon nanotube fiber has tensile strength of 4 GPa, single fiber diameter of 10 μm, continuous length of 15 m, room temperature thermal conductivity of 270 W / mK, and elongation at break of 4.8%; the hydroxylated pretreatment is: soaking the above dried continuous carbon nanotube fiber in a mixed solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 7:3, and placing in an 80℃ oil bath for 1.0 h. After the end, it is taken out and soaked in distilled water at room temperature for 0.5 h, and finally dried to obtain the hydroxylated pretreated carbon nanotube fiber.

[0088] ② preparing graphene oxide interface layer: preparing an aqueous solution of graphene oxide with a concentration of 0.6 mg / mL, placing the hydroxylated pretreated carbon nanotube fiber in the aqueous solution of graphene oxide and standing for 30 min, and then taking out the solution to obtain carbon nanotube fiber with graphene oxide interface layer, and the thickness of the graphene oxide interface layer is 0.05 μm.

[0089] ③ preparing graphene interface layer by high temperature annealing technology: placing the above carbon nanotube fiber with graphene oxide interface layer in a high temperature furnace, extracting vacuum to 20 Pa, continuously introducing argon, setting the annealing temperature to 1000℃, setting the holding time (annealing time) to 2 h, and then reducing to room temperature at a cooling rate of 0.5℃ / min to obtain carbon nanotube fiber with graphene interface layer.

[0090] ④ weaving the above carbon nanotube fiber with graphene interface layer to obtain a piercing preform, and reacting zirconium-silicon precursor solution with the piercing preform by impregnation pyrolysis method (PIP process of impregnation / curing / pyrolysis) to prepare ceramic matrix composite material with a density of 2.1 g / cm 3

[0091] Mechanical property test under high temperature and aerobic environment: the tensile strength of the ceramic matrix composite material prepared in the present comparative example is 72 MPa under 1500℃ air environment.

[0092] Comparative Example 2​

[0093] ① providing continuous carbon nanotube fibers; the continuous carbon nanotube fibers have a tensile strength of 4 GPa, a single fiber diameter of 10 μm, a continuous length of 15 m, a room temperature thermal conductivity of 270 W / mK, and an elongation at break of 4.8%.

[0094] ② preparing a SiCN interface layer: the continuous carbon nanotube fibers are placed in a chemical vapor deposition furnace, vacuum is extracted, the pressure in the reaction furnace is 25 Pa, the temperature in the reaction furnace is controlled at 1300℃, and the temperature is maintained for 10 min to ensure that the temperature in the furnace is uniform. Next, heated polysilicon carbon nitride is carried into the cavity by nitrogen gas as a carrier gas, the heating temperature of the polysilicon carbon nitride is controlled at 120℃, while continuously carrying the polysilicon carbon nitride into the cavity by the carrier gas, hydrogen and ammonia are introduced into the furnace cavity, the volume flow ratio of nitrogen, hydrogen and ammonia is 10:5:2, and the nitrogen flow is controlled at 2 L / min. After the reaction furnace is maintained at 1300℃ for 4 h, a SiCN interface layer is formed on the surface of the carbon nanotube fibers, and the thickness of the SiCN interface layer is 1.0 μm. Then, the temperature is lowered, and the heating of the polysilicon carbon nitride and the introduction of ammonia and hydrogen are stopped in turn. Nitrogen is continuously introduced during the entire cooling process until the temperature is lowered to room temperature. The sample is taken out to obtain carbon nanotube fibers with a SiCN interface layer.

[0095] ③ weaving the carbon nanotube fibers with the SiCN interface layer described above to obtain a piercing preform, reacting a zirconium-silicon precursor solution with the piercing preform by an impregnation-pyrolysis method (PIP process of impregnation / curing / pyrolysis) to prepare a ceramic matrix composite material with a density of 2.1 g / cm 3

[0096] High-temperature mechanical property test in an oxygen environment: the tensile strength of the ceramic matrix composite material prepared in the present comparative example is 119 MPa at 1500℃ in an air environment.

[0097] Comparative Example 3

[0098] ① the same as step ① of Example 1.

[0099] ​② Same as step 2 of Example 1.

[0100] ③ Same as step 3 of Example 1.

[0101] ④ Preparation of pyrolytic carbon interface layer: the carbon nanotube fiber with graphene interface layer was placed in a chemical vapor deposition furnace, and a pyrolytic carbon interface layer was deposited on the surface of the graphene interface layer of the carbon nanotube fiber by chemical vapor deposition method in an atmosphere containing argon and methane gas at 1000℃ and 25Pa, the thickness of the pyrolytic carbon interface layer was 1.0μm, and a carbon nanotube fiber with graphene / pyrolytic carbon composite interface layer was obtained; wherein the volume flow ratio of argon and methane gas was 1:1.

[0102] ⑤ The carbon nanotube fiber with graphene / pyrolytic carbon composite interface layer was woven to obtain a piercing preform, and a zirconium-silicon precursor solution was reacted with the piercing preform by a dip-pyrolysis method (PIP process of dip / solidification / pyrolysis) to prepare a ceramic matrix composite material with a density of 2.1g / cm 3

[0103] High-temperature mechanical property test in aerobic environment: the tensile strength of the ceramic matrix composite material prepared in the present example was 95MPa at 1500℃ in air environment.

[0104] Comparative Example 4

[0105] ① Same as step 1 of Example 1.

[0106] ② Same as step 2 of Example 1.

[0107] ③ Same as step 3 of Example 1.

[0108] ​(4) Preparing a SiC interface layer: the carbon nanotube fiber with the graphene interface layer is placed in a chemical vapor deposition furnace, and a silicon carbide interface layer (SiC interface layer) is deposited on the surface of the graphene interface layer of the carbon nanotube fiber by chemical vapor deposition at 1050°C and 25 Pa in an atmosphere containing trichloromethylsilane, hydrogen and argon (volume flow ratio of trichloromethylsilane, hydrogen and argon is 1:2:10), and the thickness of the silicon carbide interface layer is 1.0 μm, to obtain a carbon nanotube fiber with a graphene / silicon carbide composite interface layer.

[0109] (5) The carbon nanotube fiber with the graphene / silicon carbide composite interface layer is woven to obtain a piercing preform, and a zirconium-silicon precursor solution is reacted with the piercing preform by a dip-pyrolysis method (PIP process of dip / solidification / pyrolysis) to obtain a ceramic matrix composite material with a density of 2.1 g / cm 3

[0110] High-temperature mechanical property test in an aerobic environment: the tensile strength of the ceramic matrix composite material prepared in the above-mentioned comparative example is 231 MPa at 1500°C in an air environment.

[0111] The part of the present application not described in detail is the technology known to those skilled in the art.

[0112] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.​

Claims

1. A method for preparing a carbon nanotube fiber-reinforced ceramic matrix composite material, characterized in that, The method includes the following steps: (1) Provide continuous carbon nanotube fibers and perform hydroxylation pretreatment to obtain hydroxylated pretreated carbon nanotube fibers; (2) Prepare an aqueous solution of graphene oxide, and then immerse the hydroxylated pretreated carbon nanotube fibers in the aqueous solution of graphene oxide to obtain carbon nanotube fibers with an interface layer of graphene oxide; the concentration of the aqueous solution of graphene oxide is 0.6~6.0 mg / mL; the immersion time is 10~60 min; (3) The carbon nanotube fibers with graphene oxide interface layer are annealed and cooled to room temperature to obtain carbon nanotube fibers with graphene interface layer; the annealing temperature is 800~1000℃; the cooling rate is not greater than 1℃ / min. (4) Using polysilicon carbazide as a precursor, a SiCN interface layer is deposited on the surface of the graphene interface layer of the carbon nanotube fiber with a graphene interface layer by chemical vapor deposition to obtain carbon nanotube fiber with a graphene / SiCN composite interface layer; in step (4), the polysilicon carbazide is heated and then introduced into the chemical vapor deposition furnace through the carrier gas nitrogen, while hydrogen and ammonia are introduced into the chemical vapor deposition furnace to deposit the SiCN interface layer; wherein, the volume flow rate ratio of nitrogen, hydrogen and ammonia is 10:5:(1~4). (5) The carbon nanotube fibers with graphene / SiCN composite interface layer are woven into a preform, and the ceramic precursor is reacted with the preform by impregnation pyrolysis method to obtain a ceramic matrix composite material toughened by carbon nanotube fibers.

2. The preparation method according to claim 1, characterized in that: The continuous carbon nanotube fiber has a tensile strength of not less than 3 GPa, a single filament diameter of 8~15 μm, a continuous length of not less than 10 m, a room temperature thermal conductivity of not less than 200 W / (m·K), and / or an elongation at break of not less than 4%.

3. The preparation method according to claim 1, characterized in that: The hydroxylation pretreatment involves immersing continuous carbon nanotube fibers in a mixed solution of concentrated sulfuric acid and hydrogen peroxide in a volume ratio of (6~8):(2~4) and keeping them at 75~88℃ for 0.5~1.5h, followed by soaking in distilled water and drying to obtain hydroxylated pretreated carbon nanotube fibers.

4. The preparation method according to claim 1, characterized in that: The thickness of the graphene oxide interface layer is 0.05~0.5μm.

5. The preparation method according to claim 1, characterized in that, In step (3): The annealing process takes 1 to 5 hours.

6. The preparation method according to claim 1, characterized in that: The heating temperature of the polysiloxane is 110~150℃; and / or The SiCN interface layer is deposited at a temperature of 1200~1500℃ for 3.5~5h, and the pressure inside the chemical vapor deposition furnace is 10~150Pa.

7. The preparation method according to claim 1, characterized in that: The thickness of the SiCN interface layer is 0.3~1.0 μm.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The ceramic precursor is one or more of zirconium-silicon precursor, silicon carbide precursor, zirconium carbide precursor, and hafnium carbide precursor; and / or The density of the carbon nanotube fiber-reinforced ceramic matrix composite material is 2.0~2.5 g / cm³. 3 .

9. A carbon nanotube fiber-reinforced ceramic matrix composite material prepared by any one of claims 1 to 8.

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