阅读说明：本技术 一种多尺度增强梯度陶瓷基复合材料燃气舵及其制备方法 (Multi-scale enhanced gradient ceramic matrix composite gas rudder and preparation method thereof ) 是由 罗瑞盈 崔光远 于 2021-09-29 设计创作，主要内容包括：一种多尺度增强梯度陶瓷基复合材料燃气舵的快速制备方法,制备方法包括：采用连续碳纤维制备出几近无余量陶瓷基复合材料燃气舵一级预制体；在预制体内部纤维表面制备石墨烯界面相得到二级预制体,采用定向流动浸渍-固化-热解工艺结合化学气相沉积工艺对制备有石墨烯界面相的二级预制体进行快速致密化,得到基体组分梯度分布的多尺度增强陶瓷基复合材料燃气舵坯体；将致密化后的燃气舵坯体机械加工至燃气舵设计尺寸,根据本发明的一种多尺度增强梯度陶瓷基复合材料燃气舵的快速制备方法,可有效缩短燃气舵制备周期,所制备的燃气舵气孔率低,纤维整体增强效果优异,有效提高了燃气舵承载能力、抗烧蚀性能以及高温稳定性。(A rapid preparation method of a multi-scale enhanced gradient ceramic matrix composite gas vane comprises the following steps: preparing a near allowance-free ceramic matrix composite gas rudder primary preform by adopting continuous carbon fibers; preparing a graphene interface phase on the surface of a fiber in the preform to obtain a secondary preform, and rapidly densifying the secondary preform with the graphene interface phase by adopting a directional flow impregnation-curing-pyrolysis process combined with a chemical vapor deposition process to obtain a multi-scale enhanced ceramic matrix composite gas vane blank with gradient distribution of matrix components; according to the rapid preparation method of the multi-scale enhanced gradient ceramic matrix composite gas rudder, the preparation period of the gas rudder can be effectively shortened, the porosity of the prepared gas rudder is low, the overall reinforcing effect of fibers is excellent, and the bearing capacity, the anti-ablation performance and the high-temperature stability of the gas rudder are effectively improved.)

1. A preparation method of a multi-scale enhanced gradient ceramic matrix composite gas vane is characterized by comprising the following steps:

step 1: preparing a primary prefabricated body of the gas rudder by adopting continuous carbon fibers as a toughening phase and combining the design size of the gas rudder; the fiber volume content in the primary preform is 30-45%; the primary prefabricated body structure is any one of three-dimensional weaving, layer laying stitching, fine weaving and puncturing and a 2.5D structure;

step 2: preparing a graphene interface phase on the surface of carbon fibers in the primary preform by adopting an ultrasonic-assisted vacuum impregnation method to obtain a secondary preform;

and step 3: adopting a directional flow dipping-curing-pyrolysis process to densify the secondary prefabricated body obtained in the step 2, and introducing silicon carbide nanowires by combining a chemical vapor deposition process to obtain a multi-scale enhanced ceramic matrix composite gas vane blank body with gradient distribution of matrix components;

and 4, step 4: and (4) machining the gas vane blank obtained in the step (3) to reach the structural size of the gas vane.

2. The method for rapidly manufacturing the multi-scale enhanced gradient ceramic matrix composite gas rudder according to claim 1, wherein the method comprises the following steps: the preparation steps of the step 2 are as follows:

placing graphene in acetone for ultrasonic dispersion for 1-3 h, and controlling the ultrasonic power at 30-60 kW to obtain graphene/acetone solution subjected to ultrasonic dispersion;

placing the primary preform in a vacuum impregnation device, vacuumizing until the air pressure in the vacuum impregnation device is less than 1Pa, stopping vacuumizing, adding the graphene/acetone solution subjected to ultrasonic dispersion, and maintaining for 0.5-2 hours to fully disperse the graphene in the primary preform;

and then, raising the temperature in the vacuum impregnation device to 50-100 ℃, and preserving the heat for 5-10 hours to fully volatilize the acetone to obtain a secondary preform with a graphene interface phase.

3. The method for preparing the multi-scale enhanced gradient ceramic matrix composite gas vane according to claim 2, wherein the method comprises the following steps: the concentration of the graphene/acetone solution is 0.01-0.1 mg/mL.

4. The method for rapidly manufacturing the multi-scale reinforced gradient ceramic matrix composite gas rudder according to any one of claims 1, 2 and 3, wherein the method comprises the following steps: step 3 performed a total of four densification cycles.

5. The method for preparing the multi-scale enhanced gradient ceramic matrix composite gas vane according to claim 4, wherein the method comprises the following steps: the single densification cycle comprises the whole technological process of directional flow impregnation-solidification-pyrolysis, and the process is that the secondary preform in the step 2 is placed in densification equipment, the inner cavity of the densification equipment is in clearance fit with the outer surface of the secondary preform, the densification equipment is vacuumized to the internal pressure of the densification equipment less than 1Pa, then impregnation liquid is injected, the space of the inner cavity of the densification equipment is fully filled with the impregnation liquid, after the impregnation liquid is injected for 1-2 hours, the densification equipment with the preform is placed in an environment of 200-400 ℃, the secondary preform and the precursor in the impregnation liquid are subjected to cross-linking solidification, and the solidification time is 1 hour;

and (3) putting the impregnated and cured secondary preform into a high-temperature environment for pyrolysis, wherein the pyrolysis process comprises the following steps: and introducing nitrogen as a protective gas in the pyrolysis process, wherein the heating rate is 2-10 ℃/min, the pyrolysis temperature is 1000-1500 ℃, and the temperature is kept constant for 1-2 hours and then is reduced to the room temperature.

6. The method for preparing a multi-scale enhanced gradient ceramic matrix composite gas vane according to any one of claims 1, 2, 3 and 5, wherein the method comprises the following steps: the preparation method of the impregnation liquid used for densification comprises the following steps: dissolving an organic zirconium precursor and polycarbosilane in a xylene solution according to a mass ratio of 2:1 to prepare a precursor solution with the mass fraction of 30-50%, and adding MoSi with the mass fraction of 0-40% into the obtained precursor solution₂Carrying out ultrasonic dispersion on the ceramic powder to obtain a final impregnation liquid;

wherein MoSi in the impregnating solution used in the first densification cycle₂The mass fraction of the ceramic powder is 30-40%, and MoSi in the impregnation liquid used in the second densification period₂The mass fraction of the ceramic powder is 20-30%, and MoSi in the impregnation liquid used in the third densification period₂The mass fraction of the ceramic powder is 10-20%, and the impregnating solution used in the fourth densification period does not contain MoSi₂Adding ceramic powder; MoSi₂Purity of ceramic powder>99.5% particle size<2 μm。

7. The method for preparing the multi-scale enhanced gradient ceramic matrix composite gas vane according to claim 5, wherein the method comprises the following steps: the densification equipment is made of metal, guide grooves are uniformly distributed in an inner cavity, an injection port and a liquid discharge port are respectively arranged at two ends of the densification equipment, the injection port is connected with an injection machine, the liquid discharge port is connected with a steeping liquor collecting tank, and the rear end of the steeping liquor collecting tank is connected with a vacuum pump; the flow rate of the impregnation liquid in the secondary preform is controlled by regulating the injection pressure during the impregnation process.

8. The method for preparing a multi-scale enhanced gradient ceramic matrix composite gas vane according to any one of claims 1, 2, 3, 5 and 7, wherein the method comprises the following steps: in step 3, before the last densification cycle, introducing the silicon carbide nanowires by adopting a chemical vapor deposition process, and the steps are as follows:

after three densification cycles, the secondary preform is placed in a 0.05-0.1 mol/L cobalt acetate/ethanol solution for ultrasonic treatment for 0.5-1 h, the ultrasonic power is controlled at 30-50 kW, and then the secondary preform is dried at 50-100 ℃ for 2-5 h;

and drying and then placing the silicon carbide nanowire in chemical vapor deposition equipment, wherein trichloromethylsilane is used as deposition gas, argon is used as diluent gas, hydrogen is used as reducing gas to prepare the silicon carbide nanowire, the deposition temperature is 800-1200 ℃, the deposition time is 1-5 h, and the deposition pressure is 500-1500 Pa, wherein the trichloromethylsilane flow is 50-200 g/h, the argon flow is 100-500 mL/min, and the hydrogen flow is 50-150 mL/min.

9. The ceramic matrix composite gas vane prepared by the method of any one of claims 1, 2, 3, 5 and 7.

Technical Field

The invention relates to the field of materials, in particular to a multi-scale enhanced gradient ceramic matrix composite gas vane and a preparation method thereof.

Background

The gas rudder is a control surface part positioned at the tail part of the aircraft and is used for carrying out attitude adjustment on the aircraft so as to adjust the flight track of the aircraft. As an important component of the aircraft, the weight of the gas vane is related to the weight of the whole fuselage, and in order to improve the thrust-weight ratio of the aircraft, a light material is required to reduce the weight of the gas vane to the maximum extent. As a bearing part, in the flying process of an aircraft, the gas vane not only needs to bear large overload, but also receives great aerodynamic force generated when the aircraft flies at high speed, so that the gas vane material has the light characteristic and needs to ensure excellent mechanical property. In addition, during the flight, the surface of the gas vane structure is subjected to strong pneumatic heating, the surface temperature is rapidly increased in a short time, and large thermal stress is generated, so that the material used for the gas vane has excellent pneumatic heating resistance and ablation resistance.

The carbon fiber reinforced silicon carbide ceramic matrix composite has the advantages of light weight, excellent mechanical property, high specific strength, high specific modulus, high dimensional stability, high temperature resistance, low thermal expansion coefficient and difficult catastrophic damage, and is suitable for alternative materials of aerospace hot-end components. The carbon fiber reinforced silicon carbide ceramic matrix composite material is adopted to prepare the gas rudder, so that the quality of components can be effectively reduced and the effective load of an aircraft can be improved on the premise of ensuring high reliability.

In order to improve the ablation resistance of the silicon carbide ceramic matrix composite, refractory high-temperature resistant ceramics with high melting point are generally introduced into the matrix. Wherein ZrC has the advantages of high melting point (3540 ℃), high hardness, high thermal conductivity, high chemical stability and the like, the oxidation initiation temperature is 1700 ℃, and glass phase ZrO with high viscosity and fluidity can be generated in a high-temperature aerobic environment₂，ZrO₂The existence of the ZrO can close cracks to prevent oxygen from permeating into the composite material, can meet the requirements of the gas vane on the ablation resistance and oxidation resistance of the material at ultrahigh temperature, but when the oxidation temperature is lower, ZrO produced by oxidation₂The fusion phenomenon is difficult to generate, and the function of isolating oxygen is difficult to play; MoSi₂Has high temperature oxidation resistanceExcellent performance and high thermal conductivity, is an important additive for modifying the ablation resistance of the ceramic matrix composite material, and MoSi is added under the condition of low oxygen partial pressure₂Oxidation to form glassy SiO₂And solid Mo₅Si₃(5MoSi₂+7O₂＝Mo₅Si₃+7SiO₂) SiO in the glassy state₂Can prevent oxygen from further permeating, improve the oxidation resistance and ablation resistance of the material, but under the condition of high oxygen partial pressure, MoSi₂The simultaneous oxidation of Mo and Si occurs to generate volatile MoO₃Gas, causing defects (2 MoSi) in the matrix₂+7O₂＝2MoO₃+7SiO₂). In addition, under the condition of high-temperature airflow scouring, the ceramic matrix composite material can generate the phenomena of block collapse and falling off due to the mismatch of internal thermal expansion coefficients and the like. Therefore, the ceramic matrix composite system needs to be optimally designed to meet the requirements of the gas vane on the properties of light weight, high strength, ablation resistance, oxidation resistance, good high-temperature stability and the like of the material.

The traditional preparation process of the carbon fiber reinforced ceramic matrix composite has the problems of long preparation period, easy surface crusting, high internal porosity and the like, in order to improve the densification degree of the material and prepare a component with a complex shape, multiple times of mechanical processing and heat treatment are needed in the preparation process, the preparation period is prolonged, the overall reinforcement of fibers is damaged, and the mechanical, oxidation and ablation resistance of the material are greatly reduced due to the excessively high internal porosity of the carbon fiber reinforced ceramic matrix composite prepared by the traditional process, so that a new preparation process is needed to be explored to shorten the preparation period of the carbon fiber reinforced ceramic matrix composite, improve the densification degree of the composite and further improve the comprehensive performance of the material.

The carbon fiber has poor surface wettability, low reactivity and high inertia, so that the interface bonding property between the carbon fiber and a matrix is poor, and the excellent performance of the carbon fiber in the composite material is difficult to be fully exerted, so that an interface phase needs to be introduced between the carbon fiber and the matrix to solve the problem of poor interface performance between the fiber and the matrix.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of a multi-scale enhanced gradient ceramic matrix composite gas vane so as to shorten the preparation period of the ceramic matrix composite gas vane and prepare the light, high-strength and ablation-resistant gas vane.

The invention also aims to provide the ceramic matrix composite material gas vane prepared by the method.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: a preparation method of a multi-scale enhanced gradient ceramic matrix composite gas vane comprises the following steps:

step 1: preparing a primary prefabricated body of the gas rudder by adopting continuous carbon fibers as a toughening phase and combining the design size of the gas rudder; the fiber volume content in the primary preform is 30-45%, and the rest is pores; the primary prefabricated body structure is any one of three-dimensional weaving, layer laying stitching, fine weaving and puncturing and a 2.5D structure;

step 2: preparing a graphene interface phase on the surface of carbon fibers in the primary preform by adopting an ultrasonic-assisted vacuum impregnation method to obtain a secondary preform;

and step 3: adopting a directional flow dipping-curing-pyrolysis process to densify the secondary preform obtained in the step 2, introducing silicon carbide nanowires by combining a chemical vapor deposition process, and regulating and controlling the component content of dipping liquid used in different densification periods to obtain a multi-scale enhanced ceramic matrix composite gas vane blank with gradient distribution of matrix components, thereby improving the oxidation resistance, high-speed airflow scouring resistance and ablation resistance of the gas vane;

and 4, step 4: and (4) machining the gas vane blank obtained in the step (3) to reach the structural size of the gas vane.

The preparation steps of the step 2 are as follows:

placing graphene in acetone for ultrasonic dispersion for 1-3 h, and controlling the ultrasonic power at 30-60 kW to obtain graphene/acetone solution subjected to ultrasonic dispersion;

placing the primary preform in a vacuum impregnation device, vacuumizing until the air pressure in the vacuum impregnation device is less than 1Pa, stopping vacuumizing, adding the graphene/acetone solution subjected to ultrasonic dispersion, and maintaining for 0.5-2 hours to fully disperse the graphene in the primary preform;

and then, raising the temperature in the vacuum impregnation device to 50-100 ℃, and preserving the heat for 5-10 hours to fully volatilize the acetone to obtain a secondary preform with a graphene interface phase.

The concentration of the graphene/acetone solution is 0.01-0.1 mg/mL.

Step 3 performed a total of four densification cycles.

The single densification cycle comprises the whole technological process of directional flow impregnation-solidification-pyrolysis, and the process is that the secondary preform in the step 2 is placed in densification equipment, the inner cavity of the densification equipment is in clearance fit with the outer surface of the secondary preform, the densification equipment is vacuumized to the internal pressure of the densification equipment less than 1Pa, then impregnation liquid is injected, the space of the inner cavity of the densification equipment is fully filled with the impregnation liquid, after the impregnation liquid is injected for 1-2 hours, the densification equipment with the preform is placed in an environment of 200-400 ℃, the secondary preform and the precursor in the impregnation liquid are subjected to cross-linking solidification, and the solidification time is 1 hour;

and (3) putting the impregnated and cured secondary preform into a high-temperature environment for pyrolysis, wherein the pyrolysis process comprises the following steps: and introducing nitrogen as a protective gas in the pyrolysis process, wherein the heating rate is 2-10 ℃/min, the pyrolysis temperature is 1000-1500 ℃, and the temperature is kept constant for 1-2 hours and then is reduced to the room temperature.

The preparation method of the impregnation liquid used for densification comprises the following steps: dissolving an organic zirconium precursor and polycarbosilane in a xylene solution according to a mass ratio of 2:1 to prepare a precursor solution with the mass fraction of 30-50%, and adding MoSi with the mass fraction of 0-40% into the obtained precursor solution₂Carrying out ultrasonic dispersion on the ceramic powder to obtain a final impregnation liquid;

wherein MoSi in the impregnating solution used in the first densification cycle₂The mass fraction of the ceramic powder is 30-40%, and MoSi in the impregnation liquid used in the second densification period₂The mass fraction of the ceramic powder is 20-30%, and MoSi in the impregnation liquid used in the third densification period₂The mass fraction of the ceramic powder is 10-20%, and the impregnating solution used in the fourth densification period does not contain MoSi₂Adding ceramic powder; MoSi₂Purity of ceramic powder>99.5% particle size<2μm。

The densification equipment is made of metal, guide grooves are uniformly distributed in an inner cavity, an injection port and a liquid discharge port are respectively arranged at two ends of the densification equipment, the injection port is connected with an injection machine, the liquid discharge port is connected with a steeping liquor collecting tank, and the rear end of the steeping liquor collecting tank is connected with a vacuum pump; the flow rate of the impregnation liquid in the secondary preform is controlled by regulating the injection pressure during the impregnation process.

In step 3, before the last densification cycle, introducing the silicon carbide nanowires by adopting a chemical vapor deposition process, and the steps are as follows:

after three densification cycles, the secondary preform is placed in a 0.05-0.1 mol/L cobalt acetate/ethanol solution for ultrasonic treatment for 0.5-1 h, the ultrasonic power is controlled at 30-50 kW, and then the secondary preform is dried at 50-100 ℃ for 2-5 h;

and drying and then placing the silicon carbide nanowire in chemical vapor deposition equipment, wherein trichloromethylsilane is used as deposition gas, argon is used as diluent gas, hydrogen is used as reducing gas to prepare the silicon carbide nanowire, the deposition temperature is 800-1200 ℃, the deposition time is 1-5 h, and the deposition pressure is 500-1500 Pa, wherein the trichloromethylsilane flow is 50-200 g/h, the argon flow is 100-500 mL/min, and the hydrogen flow is 50-150 mL/min.

The ceramic matrix composite gas rudder prepared by the method of the technical scheme is provided.

The invention provides the multi-scale enhanced gradient ceramic matrix composite gas rudder prepared by the method, and the prepared ceramic matrix composite gas rudder has the advantages of short preparation period, high densification degree, light weight, high strength, oxidation resistance, excellent ablation resistance and the like.

The preparation process of the invention has the following excellent effects:

(1) the ceramic matrix composite gas rudder matrix system prepared by the invention is SiC-ZrC-MoSi₂System, MoSi₂The content of the ZrC/SiC composite material is gradually reduced from the inside of the composite material to the surface of the composite material in a gradient manner, and the outermost layer matrix only contains ZrC and SiC components. Oxidation of SiC on the surface of the substrate in a high temperature oxidation environmentSiO₂ZrO formed by oxidation with ZrC₂Will form SiO₂-ZrO₂The molten glass mixture spreads on the surface of the substrate under the action of air flow, and plays a role in isolating oxygen. With further increase in temperature, ZrO in a glassy state₂Will continue to prevent the diffusion of oxygen and reduce the partial pressure of oxygen in the substrate, while the SiO on the surface of the substrate₂The viscosity will decrease due to the increase of temperature, the scouring action of the gas flow and the SiO₂Volatilization of (2) causes SiO near the surface layer of the substrate₂Gradually decreases, SiC in the matrix is gradually consumed, and MoSi in the material is generated₂Vitreous SiO generated under low oxygen partial pressure inside the matrix₂Can gradually permeate into the defect part of the outer surface to fill up SiO₂The loss of the material is reduced, and the ablation resistance of the material is improved. MoSi₂The gradient distribution structure in the base body can also reduce the difference of thermal expansion coefficients between different positions in the base body, reduce the thermal stress generated by the material under the high-temperature condition and the driving force generated by cracks between different layers to a certain extent, and improve the use reliability and the high-temperature stability of the gas rudder. In addition, the oxidation resistance and ablation resistance of the gas vane in a wide temperature range are improved through the oxidation mechanism of different components in the matrix at different temperature sections.

(2) The ceramic matrix composite gas rudder prepared by the invention not only toughens fibers, but also introduces a silicon carbide nanowire toughening mechanism into the matrix, so that a multi-scale toughening effect is achieved, the introduction of the silicon carbide nanowires can resist the mechanical erosion effect of high-speed gas on the surface matrix, and in addition, in the loading process of the material, the silicon carbide nanowires can induce crack deflection, and the pulling-out and breaking of the silicon carbide nanowires can also consume part of energy, so that the mechanical property of the material is improved.

(3) And a graphene interface phase is introduced on the surface of the continuous carbon fiber. Because the surface wettability of the carbon fiber is poor, the reactivity is low, the interface bonding property between the carbon fiber and a matrix is poor, micro pores exist between the reinforced fiber and the matrix in the composite material, and the load can not be effectively transferred between the fiber and the matrix in the loading process. In order to solve the problem, the graphene interface phase with excellent mechanical property and thermophysical property is introduced between the fiber and the matrix, and the introduction of the graphene interface phase can effectively increase the specific surface area, improve the wettability between the fiber and the impregnating solution and reduce the internal pores of the prepared material. In addition, due to the fact that the graphene is pulled out and is bridged with cracks and crack deflection caused by the graphene, the mechanical property of the composite material can be effectively improved due to the introduction of the graphene.

(4) The densification is carried out by adopting a directional flow impregnation-solidification-pyrolysis process. Compared with the traditional densification process, the directional flow impregnation process can effectively discharge residual gas in the pores in the secondary preform, greatly shortens the densification period, reduces the porosity of the prepared material, and improves the comprehensive performance of the material.

Drawings

FIG. 1 is a micro-topography of a silicon carbide nanowire deposited according to a first embodiment of the present invention.

The specific implementation mode is as follows:

the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The experimental procedures in the following examples are conventional unless otherwise specified.

The test materials used in the following examples were purchased from natural conventional reagent stores unless otherwise specified.

In the quantitative tests in the following examples, three replicates were set, and the data are the mean or the mean ± standard deviation of the three replicates.

The invention provides a preparation method of a multi-scale enhanced gradient ceramic matrix composite gas rudder, which comprises the following steps:

step 1: preparing a primary preform of the gas rudder almost without allowance by using continuous carbon fibers as a toughening phase and combining the actual design size of the gas rudder; the fiber volume content in the primary preform is 30-45%, and the primary preform structure is one of three-dimensional weaving, layer laying stitching, fine weaving and puncturing, 2.5D structure and the like; almost no excess fiber preform avoids the damage of subsequent machining to the continuity of the fiber, ensures the integrity of the fiber in the prepared preform, and effectively improves the mechanical property of the prepared gas vane.

Step 2: and preparing a graphene interface phase on the surface of the carbon fiber in the primary preform to obtain a secondary preform. The specific method for preparing the graphene interface phase comprises the following steps: preparing a graphene interface phase on the surface of a fiber in a preform by adopting an ultrasonic-assisted vacuum impregnation method, placing graphene in acetone for ultrasonic dispersion for 1-3 hours, controlling the ultrasonic power at 30-60 kW to obtain an ultrasonically dispersed graphene/acetone solution, wherein the concentration of the graphene/acetone solution is 0.01-0.1 mg/mL, placing a primary preform in a vacuum impregnation device, vacuumizing until the air pressure in the impregnation device is less than 1Pa, stopping vacuumizing, adding the ultrasonically dispersed graphene/acetone solution into the impregnation device, maintaining the state for 0.5-2 hours, fully dispersing the graphene in the primary preform, raising the internal temperature of the vacuum impregnation device to 50-100 ℃, preserving the heat for 5-10 hours, and fully volatilizing the acetone to obtain the carbon fiber preform with the graphene interface phase.

And step 3: and (3) rapidly densifying the secondary preform obtained in the step (2) by adopting a directional flow impregnation-curing-pyrolysis process and a chemical vapor deposition process to obtain the ceramic matrix composite gas vane blank with the gradient distribution of matrix components. A total of four densification cycles were performed, each including three steps of directional flow impregnation, curing, and pyrolysis. Impregnation in directional flow impregnationThe preparation method of the impregnation liquid comprises the following steps: dissolving an organic zirconium precursor and polycarbosilane in a xylene solution according to a mass ratio of 2:1 to prepare a precursor solution with the mass fraction of 30-50%, and adding MoSi with the mass fraction of 0-40% into the obtained precursor solution₂And (4) carrying out ultrasonic dispersion on the ceramic powder to obtain the final impregnation liquid. Wherein MoSi in the impregnating solution used in the first densification cycle₂The mass fraction of the ceramic powder is 30-40%, and MoSi in the impregnation liquid used in the second densification period₂The mass fraction of the ceramic powder is 20-30%, and MoSi in the impregnation liquid used in the third densification period₂The mass fraction of the ceramic powder is 10-20%, and the impregnating solution used in the fourth densification period does not contain MoSi₂Adding ceramic powder. The MoSi is₂Purity of ceramic powder>99.5% particle size<2 μm. The directional flow impregnation process method comprises the following steps: placing a second-stage prefabricated body with a graphene interface phase in nearly zero-allowance densification equipment, wherein the densification equipment is made of metal materials, guide grooves are uniformly distributed in an inner cavity, an injection port and a liquid discharge port are formed in two ends of the equipment respectively, the injection port is connected with an injection machine, the liquid discharge port is connected with a steeping liquor collecting tank, the rear end of the steeping liquor collecting tank is connected with a vacuum pump, and the second-stage prefabricated body is firstly vacuumized to the internal pressure of the tool<1Pa, then injecting a dipping solution, controlling the flow rate of the dipping solution in the preform by regulating and controlling the injection pressure in the dipping process, fully filling the inner space of densification equipment without allowance with the dipping solution, maintaining the dipping solution for injection for 1-2 hours, and then placing the densification equipment in an environment of 200-400 ℃ to enable the precursor to be crosslinked and cured, wherein the precursor refers to an organic zirconium precursor and polycarbosilane in a precursor solution, and the curing time is 1 hour. And (3) putting the impregnated and cured secondary preform into a high-temperature environment for pyrolysis, wherein the pyrolysis process comprises the following steps: and introducing nitrogen as a protective gas in the pyrolysis process, wherein the heating rate is 2-10 ℃/min, the pyrolysis temperature is 1000-1500 ℃, and the temperature is kept constant for 1-2 hours and then is reduced to the room temperature. After the third densification period is finished, preparing the silicon carbide nanowires in the matrix in situ by a chemical vapor deposition process, putting the second-stage preform after the three densification periods in a 0.05-0.1 mol/L cobalt acetate/ethanol solution for ultrasonic treatment for 0.5-1 h, controlling the ultrasonic power at 30-50 kW, and then drying the second-stage preform at 50-100 ℃ for 2 hoursAbout 5 h; and drying and then placing the silicon carbide nanowire in chemical vapor deposition equipment, wherein trichloromethylsilane is used as deposition gas, argon is used as diluent gas, hydrogen is used as reducing gas to prepare the silicon carbide nanowire, the deposition temperature is 800-1200 ℃, the deposition time is 1-5 h, and the deposition pressure is 500-1500 Pa, wherein the trichloromethylsilane flow is 50-200 g/h, the argon flow is 100-500 mL/min, and the hydrogen flow is 50-150 mL/min.

And 4, step 4: and (4) machining the product obtained in the step (3) to the design size of the gas vane.

The preparation method of the ceramic matrix composite gas rudder of the present invention is further explained with reference to the specific embodiments.

Example 1

Step 1: the method comprises the steps of designing a nearly allowance-free ceramic matrix composite gas rudder primary preform structure according to the actual design size of a gas rudder, and preparing the ceramic matrix composite gas rudder primary preform by adopting a layer laying and sewing technology, wherein the fiber volume content of the primary preform is 30%, and the used fiber is continuous carbon fiber.

Step 2: carrying out ultrasonic treatment on 0.05mg/mL graphene/acetone solution for 1h, wherein the ultrasonic power is 40kW, so that graphene is uniformly dispersed in the solution; and (3) placing the primary preform in a vacuum impregnation device, vacuumizing until the air pressure in the impregnation device is 0.5Pa, stopping vacuumizing, adding the graphene/acetone solution subjected to ultrasonic treatment into the impregnation device, maintaining for 1h to fully disperse the graphene solution in the primary preform, then raising the internal temperature of the vacuum impregnation device to 70 ℃, and keeping the temperature for 6h until the acetone is completely volatilized to obtain a secondary preform with a graphene interface phase.

And step 3: adopting a directional flow impregnation-solidification-pyrolysis process to densify a secondary preform, placing the secondary preform in almost zero-allowance densification equipment, wherein the densification equipment is made of metal materials, guide grooves are uniformly distributed in the densification equipment, an injection port and a liquid discharge port are respectively formed in two ends of the equipment, the injection port is connected with an injection machine, the liquid discharge port is connected with an impregnation liquid collecting tank, the rear end of the impregnation liquid collecting tank is connected with a vacuum pump, vacuumizing is performed firstly until the pressure is 0.5Pa, then impregnation liquid is injected, and after the impregnation liquid fully fills the internal space of the zero-allowance tool, the impregnation liquid is maintainedInjecting the impregnation solution for 1h, and then placing the densification equipment in an environment at 300 ℃ to enable the precursor in the impregnation solution to be subjected to crosslinking and curing, wherein the curing time is 1 hour. And (3) putting the impregnated and cured secondary preform at 1400 ℃ for constant-temperature pyrolysis for 1h, cooling to room temperature at the heating rate of 2 ℃/min, introducing nitrogen as a protective gas during the heating, and then cooling to room temperature. The method comprises the following steps of totally carrying out four densification cycles with the same process, wherein each densification cycle needs to carry out the whole process of directional flow impregnation, solidification and pyrolysis, and the preparation method of the impregnation liquid used in the directional flow impregnation comprises the following steps: dissolving an organic zirconium precursor and polycarbosilane in a xylene solution according to a mass ratio of 2:1 to prepare a precursor solution with a mass fraction of 45%, and adding MoSi with a mass fraction of 0-40% into the obtained precursor solution₂And (4) carrying out ultrasonic dispersion on the ceramic powder to obtain the final impregnation liquid. Wherein MoSi in the impregnating solution used in the first densification cycle₂The mass fraction of the ceramic powder is 35%, and MoSi in the impregnating solution used in the second densification period₂The mass fraction of the ceramic powder is 25 percent, and MoSi in the impregnating solution used in the third densification period₂The mass fraction of the ceramic powder is 15 percent, and the impregnating solution used in the fourth densification period has no MoSi₂Adding ceramic powder. The MoSi is₂The purity of the ceramic powder was 99.9%, and the particle size was 1 μm. After the third densification cycle is completed, silicon carbide nanowires are introduced using a chemical vapor deposition process, followed by a fourth densification cycle. The preparation method of the silicon carbide nanowire comprises the following steps: and (3) after three densification cycles, placing the second-stage preform in 0.05mol/L cobalt acetate/ethanol solution for ultrasonic treatment for 0.5h, wherein the ultrasonic power is 40kW, then drying the second-stage preform for 2h at 100 ℃, placing the second-stage preform in chemical vapor deposition equipment after drying, preparing the silicon carbide nanowire by using trichloromethylsilane as deposition gas, argon as diluent gas and hydrogen as reducing gas, wherein the deposition temperature is 900 ℃, the deposition time is 1h, and the deposition pressure is 700Pa, wherein the trichloromethylsilane flow is 150g/h, the argon flow is 300mL/min, and the hydrogen flow is 100 mL/min.

And 4, step 4: and finally, machining the product obtained in the last step to reach the design size.

The tungsten that prepares at present oozes copper gas rudderThe density is more than 15g/cm³The density of the gas vane of the ceramic matrix composite material obtained in the first example is 2.20g/cm³The porosity was 0.8%.

Example 2

Step 1: the method comprises the steps of designing a nearly allowance-free ceramic matrix composite gas rudder primary preform structure according to the actual design size of a gas rudder, and preparing the ceramic matrix composite gas rudder primary preform by adopting a fine weaving and puncturing technology, wherein the fiber volume content of the primary preform is 40%, and the used fibers are continuous carbon fibers.

Step 2: carrying out ultrasonic treatment on 0.05mg/mL graphene/acetone solution for 3h, wherein the ultrasonic power is 40kW, uniformly dispersing graphene in the solution, placing the primary preform in a vacuum impregnation device, vacuumizing until the air pressure in the impregnation device is 0.5Pa, stopping vacuumizing, adding the ultrasonic graphene/acetone solution into the impregnation device, maintaining for 1h, fully dispersing the graphene solution in the preform, then raising the internal temperature of the vacuum impregnation device to 70 ℃, and keeping the temperature for 6h until the acetone is completely volatilized, thereby obtaining the secondary preform with the graphene interface phase.

And step 3: the method comprises the steps of adopting a directional flow impregnation-solidification-pyrolysis process to densify a secondary preform, placing the secondary preform in almost zero-allowance densification device, wherein the densification device is made of metal materials, guide grooves are uniformly distributed in the densification device, an injection port and a liquid discharge port are formed in two ends of the device respectively, the injection port is connected with an injection machine, the liquid discharge port is connected with a steeping liquor collecting tank, the rear end of the steeping liquor collecting tank is connected with a vacuum pump, vacuumizing is firstly carried out until the pressure is 0.5Pa, then steeping liquor is injected, after the steeping liquor fully fills the internal space of the zero-allowance tool, steeping liquor injection is maintained for 1.5h, then the densification device is placed in an environment at 300 ℃ to enable a precursor in the steeping liquor to be subjected to cross-linking solidification, and the solidification time is 1 h. And (3) pyrolyzing the impregnated and cured secondary preform at 1200 ℃ for 1h at the heating rate of 4 ℃/min, introducing nitrogen as a protective gas during the pyrolysis, and then cooling to room temperature. The densification process needs four cycles (directional flow impregnation-curing-pyrolysis), and the preparation method of the impregnation liquid used in the directional flow impregnation comprises the following steps: dissolving an organic zirconium precursor and polycarbosilane in a xylene solution according to a mass ratio of 2:1 to prepare a solutionAdding MoSi with the mass fraction of 0-40% into the precursor solution with the mass fraction of 45%₂And (4) carrying out ultrasonic dispersion on the ceramic powder to obtain the final impregnation liquid. Wherein MoSi in the impregnating solution used in the first densification cycle₂The mass fraction of the ceramic powder is 40%, and MoSi in the impregnating solution used in the second densification period₂The mass fraction of the ceramic powder is 30 percent, and MoSi in the impregnating solution used in the third densification period₂The mass fraction of the ceramic powder is 20 percent, and the impregnating solution used in the fourth densification period has no MoSi₂Adding ceramic powder. The MoSi is₂The purity of the ceramic powder was 99.9%, and the particle size was 1 μm. After the third densification cycle is completed, a chemical vapor deposition process is used to introduce the silicon carbide nanowires, followed by a fourth densification cycle. The preparation method of the silicon carbide nanowire comprises the following steps: and (3) performing ultrasonic treatment on the second-stage preform for 1h in 0.05mol/L cobalt acetate/ethanol solution after three densification cycles, wherein the ultrasonic power is 40kW, drying is performed for 2h at 100 ℃, the second-stage preform is placed in chemical vapor deposition equipment after drying, the silicon carbide nanowire is prepared by using trichloromethylsilane as deposition gas, argon as diluent gas and hydrogen as reducing gas, the deposition temperature is 1000 ℃, the deposition time is 3h, and the deposition pressure is 1000Pa, wherein the trichloromethylsilane flow is 100g/h, the argon flow is 450mL/min, and the hydrogen flow is 100 mL/min.

And 4, step 4: and finally, machining the product obtained in the last step to reach the design size.

The density of the tungsten copper-infiltrated gas vane prepared at present is more than 15g/cm³The density of the gas vane of the ceramic matrix composite material obtained in the second example is 2.24g/cm³The porosity was 1.2%.

Example 3

Step 1: the method comprises the steps of designing a nearly allowance-free ceramic matrix composite gas vane primary preform structure according to the actual design size of the gas vane, and preparing the ceramic matrix composite gas vane primary preform by adopting a 2.5D technology, wherein the fiber volume content of the primary preform is 45%, and the used fiber is continuous carbon fiber.

Step 2: carrying out ultrasonic treatment on 0.02mg/mL graphene/acetone solution for 3h, wherein the ultrasonic power is 40kW, uniformly dispersing graphene in the solution, placing the primary preform in a vacuum impregnation device, vacuumizing until the air pressure in the impregnation device is 0.5Pa, stopping vacuumizing, adding the ultrasonic graphene/acetone solution into the impregnation device, maintaining for 1h to fully disperse the graphene solution in the preform, then raising the internal temperature of the vacuum impregnation device to 70 ℃, and keeping the temperature for 6h until the acetone is completely volatilized, thereby obtaining the secondary preform with the graphene interface phase.

And step 3: the method comprises the steps of adopting a directional flow impregnation-solidification-pyrolysis process to densify a secondary preform, placing the secondary preform in almost zero-allowance densification device, wherein the densification device is made of metal materials, guide grooves are uniformly distributed in the densification device, an injection port and a liquid discharge port are formed in two ends of the device respectively, the injection port is connected with an injection machine, the liquid discharge port is connected with a steeping liquor collecting tank, the rear end of the steeping liquor collecting tank is connected with a vacuum pump, vacuumizing is firstly carried out until the pressure is 0.5Pa, then steeping liquor is injected, after the steeping liquor fully fills the internal space of the zero-allowance tool, steeping liquor injection is maintained for 2 hours, then the densification device is placed in an environment of 300 ℃ to enable a precursor in the steeping liquor to be subjected to crosslinking solidification, and the solidification time is 1 hour. And (3) pyrolyzing the impregnated and cured secondary preform at 1000 ℃ for 1h, wherein the heating rate is 8 ℃/min, nitrogen is introduced as protective gas during the pyrolysis, and then the temperature is reduced to room temperature. The densification process needs four cycles (directional flow impregnation-curing-pyrolysis), and the preparation method of the impregnation liquid used in the directional flow impregnation comprises the following steps: dissolving an organic zirconium precursor and polycarbosilane in a xylene solution according to a mass ratio of 2:1 to prepare a precursor solution with a mass fraction of 45%, and adding MoSi with a mass fraction of 0-40% into the obtained precursor solution₂And (4) carrying out ultrasonic dispersion on the ceramic powder to obtain the final impregnation liquid. Wherein MoSi in the impregnating solution used in the first densification cycle₂The mass fraction of the ceramic powder is 30 percent, and MoSi in the impregnating solution used in the second densification period₂The mass fraction of the ceramic powder is 20 percent, and MoSi in the impregnating solution used in the third densification period₂The mass fraction of the ceramic powder is 10 percent, and the impregnating solution used in the fourth densification period has no MoSi₂Adding ceramic powder. The MoSi is₂The purity of the ceramic powder is 99.9 percent, and the particle size is1 μm. After the third densification cycle is completed, silicon carbide nanowires are introduced using a chemical vapor deposition process, followed by a fourth densification cycle. The preparation method of the silicon carbide nanowire comprises the following steps: and (2) performing ultrasonic treatment on the second-stage preform for 1h in 0.05mol/L cobalt acetate/ethanol solution after three densification cycles, wherein the ultrasonic power is 40kW, then drying for 2h at 100 ℃, then placing the second-stage preform in chemical vapor deposition equipment, and preparing the silicon carbide nanowire by using trichloromethylsilane as deposition gas, argon as diluent gas and hydrogen as reducing gas, wherein the deposition temperature is 1200 ℃, the deposition time is 5h, and the deposition pressure is 1500Pa, wherein the trichloromethylsilane flow is 50g/h, the argon flow is 300mL/min, and the hydrogen flow is 100 mL/min.

And 4, step 4: and finally, machining the product obtained in the last step to reach the design size.

The density of the tungsten copper-infiltrated gas vane prepared at present is more than 15g/cm³The density of the gas vane of the ceramic matrix composite obtained in example 3 was 1.99g/cm³The porosity was 1.9%.