阅读说明：本技术 航空发动机热结构件用多层陶瓷基复合材料及其制备方法 (Multilayer ceramic matrix composite for aeroengine thermal structural member 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：一种航空发动机热结构件用多层陶瓷基复合材料及其制备方法,制备方法包括以下步骤：采用连续纤维制备出纤维预制体；在预制体内部纤维表面制备热解碳和SiC纳米线复合界面相,采用真空-加压浸渍工艺对具有复合界面相的预制体进行致密化得到二级坯体,采用化学气相渗积工艺对二级坯体进行基体填充并进行预氧化得到三级坯体,采用化学气相渗积工艺在三级坯体中引入热解碳层并通过催化剂辅助沉积法引入碳纳米线得到四级坯体,最后通过熔融渗硅法在四级坯体表面制备SiC封孔涂层,所制备的陶瓷基复合材料孔隙率低,具有抗烧蚀、耐腐蚀特性,在高温有氧条件下仍能保持优异的力学性能。(A multilayer ceramic matrix composite for an aeroengine thermal structure member and a preparation method thereof are disclosed, the preparation method comprises the following steps: preparing a fiber preform by using continuous fibers; preparing pyrolytic carbon and SiC nanowire composite interface phase on the surface of fiber inside a preform, densifying the preform with the composite interface phase by adopting a vacuum-pressurization impregnation process to obtain a secondary blank, filling a matrix into the secondary blank by adopting a chemical vapor deposition process, and pre-oxidizing to obtain a tertiary blank, introducing a pyrolytic carbon layer into the tertiary blank by adopting the chemical vapor deposition process, introducing carbon nanowires into the tertiary blank by adopting a catalyst-assisted deposition method to obtain a quaternary blank, and finally preparing a SiC hole sealing coating on the surface of the quaternary blank by a fused siliconizing method.)

1. A preparation method of a multilayer ceramic matrix composite for an aircraft engine thermal structure member is characterized by comprising the following steps: the method comprises the following steps:

step 1: preparing a fiber preform by using continuous fibers as a toughening phase; the fiber preform is characterized in that the preform structure is any one of three-dimensional weaving, layer laying stitching, fine weaving and puncturing and a 2.5D structure, and the fiber volume content in the fiber preform is 30-45%;

step 2: depositing on the surface of the fiber in the fiber preform in the step 1 by adopting a chemical vapor deposition process to obtain a pyrolytic carbon and SiC nanowire composite interface to obtain a primary blank;

and step 3: adopting vacuum-pressure impregnation and cracking technology to densify the primary blank obtained in the step 2 to obtain a secondary blank, wherein the density of the secondary blank is 1.3-1.5 g/cm³；

And 4, step 4: filling the secondary blank obtained in the step 3 with a matrix by adopting a chemical vapor deposition process to prepare a SiC matrix layer until the density reaches 1.7-1.8 g/cm³Then, carrying out pre-oxidation to obtain a three-level blank;

and 5: introducing a pyrolytic carbon layer into the three-level blank by adopting a chemical vapor deposition process until the density reaches 1.9-2.0 g/cm³Then, introducing the carbon nano wire by a catalyst assisted deposition method to obtain a four-level blank;

step 6: and preparing the SiC hole sealing coating on the surface of the four-level blank by a melting siliconizing method.

2. The method for preparing a multilayer ceramic matrix composite for an aircraft engine thermal structure according to claim 1, characterized in that: in step 2, the preparation method of the pyrolytic carbon interface comprises the following steps:

placing the fiber preform in the step 1 in deposition equipment, and depositing by using propane as deposition gas and nitrogen as dilution gas, wherein the deposition temperature is 700-1000 ℃, the deposition time is 1-5 h, and the deposition pressure is 800-1500 Pa; wherein the flow rate of the propane is 50-150 g/h, and the flow rate of the nitrogen is 100-200 mL/min.

3. The process for preparing a multilayer ceramic matrix composite for an aircraft engine thermal structure according to claim 1 or 2, characterized in that: the SiC nanowire interface in the step 2 is deposited on the surface of the pyrolytic carbon interface, and the SiC nanowire interface deposition method comprises the following steps: placing the fiber preform deposited with the pyrolytic carbon interface in an ethanol solution containing nickel chloride for ultrasonic treatment, wherein the concentration of the ethanol solution of the nickel chloride is 0.2-1 mol/L, and the ultrasonic treatment time is 3-5 hours; and after the ultrasonic treatment is finished, the SiC nanowire is deposited in a SiC deposition furnace, trichloromethylsilane is used as precursor gas, hydrogen is used as reducing gas, argon is used as diluting gas to deposit the SiC nanowire, the deposition temperature is 800-1200 ℃, the deposition time is 1-5 h, and the deposition pressure is 500-1500 Pa.

4. The method for preparing a multilayer ceramic matrix composite for an aircraft engine thermal structure according to claim 3, characterized in that: the trichloromethylsilane: hydrogen gas: the flow ratio of argon was 1:30: 30.

5. The process for the preparation of a multilayer ceramic matrix composite for an aeroengine thermal structure according to any one of claims 1, 2, 4, characterized in that: the step 3 is:

placing the primary blank in dipping equipment by taking polyborosilazane as a precursor, vacuumizing until the internal pressure of the dipping equipment is less than 50Pa, and adding polyborosilazane precursor solution into the dipping equipment; xylene in the polyborosilazane precursor solution is used as a solvent, the mass fraction of polyborosilazane in the precursor solution is 10-30%, and the polyborosilazane is maintained in a vacuum state for 1-2 hours; continuously introducing inert gas into the dipping equipment for pressurization to 1-3 MPa, and maintaining the pressure for 1-2 hours;

drying the impregnated primary blank body, then placing the dried primary blank body in a cracking furnace for high-temperature cracking, wherein the cracking temperature is 900-1300 ℃, the constant temperature time is 1-2 hours, the heating rate is 3-5 ℃/min, and the vacuum-pressure impregnation and cracking process is repeated until the density reaches 1.3-1.5 g/cm³And obtaining a secondary blank.

6. The method for preparing a multilayer ceramic matrix composite for an aircraft engine thermal structure according to claim 5, characterized in that: in the step 4, trichloromethylsilane is used as an infiltration gas, hydrogen is used as a carrier gas, argon is used as a diluent gas, the SiC matrix is infiltrated, the infiltration temperature is 700-1100 ℃, the infiltration time is 50-100 h, the infiltration pressure is 1000-2000 Pa, and the infiltration is carried out until the density reaches 1.7-1.8 g/cm³And then, pre-oxidizing the material in static air at the pre-oxidation temperature of 900-1300 ℃ for 1-5 hours to obtain a three-level blank.

7. The process for the preparation of a multilayer ceramic matrix composite for aeroengine thermal structural members according to any one of claims 1, 2, 4, 6, wherein: step 5 is as follows:

placing the three-stage blank body in infiltration equipment, taking natural gas as infiltration gas and nitrogen as diluent gas, and preparing the pyrolytic carbon substrate, wherein the infiltration temperature is 700-1100 ℃, the infiltration time is 50-100 h, and the infiltrationThe pressure is 1000-1500 Pa, and the density reaches 1.9-2.0 g/cm³Then;

taking out the blank, and placing the blank in an ethanol solution of cobalt acetate for ultrasonic treatment, wherein the concentration of the ethanol solution of cobalt acetate is 0.1-0.5 mol/L;

and placing the obtained product in a high-temperature deposition furnace after ultrasonic drying for deposition of the carbon nanowires to obtain a four-level blank.

8. The method for preparing a multilayer ceramic matrix composite for an aircraft engine thermal structure according to claim 7, characterized in that: the carbon nanowire deposition process comprises the following steps: and (3) depositing by adopting a bubbling method, wherein the carrier gas is nitrogen, the deposition precursor solution is acetone, the deposition temperature is 900-1300 ℃, the deposition pressure is 1000-1500 Pa, and the deposition time is 5-10 hours.

9. The process for preparing a multilayer ceramic matrix composite for an aeroengine thermal structure according to any one of claims 1, 2, 4, 6, 8, characterized in that: step 6 is as follows: embedding the four-level blank by silicon powder, and then placing the four-level blank in a high-temperature furnace for hole sealing coating preparation, wherein the melting siliconizing temperature is 1300-1600 ℃, the constant temperature time is 1-3 hours, and the heating rate is 5-10 ℃/min.

10. A multilayer ceramic matrix composite for aircraft engine thermal structural members obtained by the method according to any one of claims 1, 2, 4, 6, 8.

Technical Field

The invention relates to the field of materials, in particular to a multilayer ceramic matrix composite material for an aeroengine thermal structural member and a preparation method thereof.

Background

The materials used by the aeroengine thermal structural component need to meet the requirements of high temperature resistance, high strength and high reliability, and along with the increase of the temperature of the front inlet of the turbine of the aeroengine, the traditional high-temperature alloy material is difficult to meet the working requirements of the engine, and in addition, the increase of the thrust-weight ratio of the aeroengine is further limited by the high density of the traditional high-temperature alloy material. Compared with the traditional high-temperature alloy material, the ceramic matrix composite material has excellent performances of low density, high strength, high temperature resistance, oxidation resistance, corrosion resistance and the like, and can be used for replacing the traditional high-temperature alloy to prepare the hot end component of the aero-engine, so that the weight of the component can be greatly reduced, the thermodynamic cycle parameter can be improved, and the cooling air quantity can be reduced, thereby obviously improving the thrust-weight ratio and the efficiency of the engine.

In the existing process method for preparing the ceramic matrix composite, due to the defects of the preparation process, inherent pores exist inside and on the outer surface of the ceramic matrix composite, the inherent pores can become inducing sources of cracks and damage the mechanical properties of the ceramic matrix composite, and in addition, the inherent pores can enable the ceramic matrix composite to be corroded by oxygen in a high-temperature aerobic environment, so that the property attenuation is caused. In the loading process of the ceramic matrix composite, the cracks only deflect at the junctions of the matrix and the interface and the fiber, the energy loss mechanism is less, and the further improvement of the performance of the ceramic matrix composite is also restricted to a certain extent.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of a multilayer ceramic matrix composite for an aeroengine thermal structural member, so as to reduce inherent pores in the composite and realize the integrated improvement of the oxidation resistance/mechanical property of the composite.

The invention also aims to provide the multilayer ceramic matrix composite material for the aeroengine thermal structural member prepared by the method.

The technical scheme is as follows:

a preparation method of a multilayer ceramic matrix composite for an aircraft engine thermal structure member comprises the following steps:

step 1: preparing a fiber preform by using continuous fibers as a toughening phase; the fiber preform is characterized in that the preform structure is any one of three-dimensional weaving, layer laying stitching, fine weaving and puncturing and a 2.5D structure, the fiber volume content in the fiber preform is 30-45%, and the rest is pores;

step 2: depositing on the surface of the fiber in the fiber preform in the step 1 by adopting a chemical vapor deposition process to obtain a pyrolytic carbon and SiC nanowire composite interface to obtain a primary blank;

and step 3: adopting vacuum-pressure impregnation and cracking technology to densify the primary blank obtained in the step 2 to obtain a secondary blank, wherein the density of the secondary blank is 1.3-1.5 g/cm³；

And 4, step 4: filling the secondary blank obtained in the step 3 with a matrix by adopting a chemical vapor deposition process to prepare a SiC matrix layer, and filling the SiC matrix with the secondary blank until the overall density reaches 1.7-1.8 g/cm³Then, carrying out pre-oxidation to obtain a three-level blank;

and 5: introducing a pyrolytic carbon layer into the three-level blank by adopting a chemical vapor deposition process until the density of the blank introduced with the pyrolytic carbon layer reaches 1.9-2.0 g/cm³Then, introducing the carbon nano wire by a catalyst assisted deposition method to obtain a four-level blank;

step 6: and preparing the SiC hole sealing coating on the surface of the four-level blank by a melting siliconizing method.

In step 2, the preparation method of the pyrolytic carbon interface comprises the following steps:

placing the fiber preform in the step 1 in deposition equipment, and depositing by using propane as deposition gas and nitrogen as dilution gas, wherein the deposition temperature is 700-1000 ℃, the deposition time is 1-5 h, and the deposition pressure is 800-1500 Pa; wherein the flow rate of the propane is 50-150 g/h, and the flow rate of the nitrogen is 100-200 mL/min.

The SiC nanowire interface in the step 2 is deposited on the surface of the pyrolytic carbon interface, and the SiC nanowire interface deposition method comprises the following steps: placing the fiber preform deposited with the pyrolytic carbon interface in an ethanol solution containing nickel chloride for ultrasonic treatment, wherein the concentration of the ethanol solution of the nickel chloride is 0.2-1 mol/L, and the ultrasonic treatment time is 3-5 hours; and after the ultrasonic treatment is finished, the SiC nanowire is deposited in a SiC deposition furnace, trichloromethylsilane is used as precursor gas, hydrogen is used as reducing gas, argon is used as diluting gas to deposit the SiC nanowire, the deposition temperature is 800-1200 ℃, the deposition time is 1-5 h, and the deposition pressure is 500-1500 Pa.

The trichloromethylsilane: hydrogen gas: the flow ratio of argon was 1:30: 30.

The step 3 is:

placing the primary blank in dipping equipment by taking polyborosilazane as a precursor, vacuumizing until the internal pressure of the dipping equipment is less than 50Pa, and adding polyborosilazane precursor solution into the dipping equipment; xylene in the polyborosilazane precursor solution is used as a solvent, the mass fraction of polyborosilazane in the precursor solution is 10-30%, and the polyborosilazane is maintained in a vacuum state for 1-2 hours; continuously introducing inert gas into the dipping equipment for pressurization to 1-3 MPa, and maintaining the pressure for 1-2 hours;

drying the dipped primary blank, putting the dried primary blank into a cracking furnace for high-temperature cracking at the cracking temperature of 900-1300 ℃, keeping the constant temperature for 1-2 hours, and increasing the temperature at the rate of 3-5 ℃/min, repeating the vacuum-pressure dipping and cracking process until the overall density of the primary blank reaches 1.3-1.5 g/cm after the densification process³And obtaining a secondary blank.

In the step 4, trichloromethylsilane is used as an infiltration gas, hydrogen is used as a carrier gas, argon is used as a diluent gas, the infiltration of the SiC matrix is carried out, the infiltration temperature is 700-1100 ℃, the infiltration time is 50-100 h, the infiltration pressure is 1000-2000 Pa, and the overall density reaches 1.7-1.8 g/cm after the secondary blank body is infiltrated and filled with the SiC matrix³And then, pre-oxidizing the material in static air at the pre-oxidation temperature of 900-1300 ℃ for 1-5 hours to obtain a three-level blank.

Step 5 is as follows:

placing the three-stage blank body in infiltration equipment, taking natural gas as infiltration gas and nitrogen as diluent gas, and preparing a pyrolytic carbon substrate, wherein the infiltration temperature is 700-1100 ℃, the infiltration time is 50-100 h, the infiltration pressure is 1000-1500 Pa, and the overall density reaches 1.9-2.0 g/cm after the pyrolytic carbon is introduced into the three-stage blank body after infiltration³；

Taking out the green body after the pyrolytic carbon is introduced, and placing the green body in an ethanol solution of cobalt acetate for ultrasonic treatment, wherein the concentration of the ethanol solution of cobalt acetate is 0.1-0.5 mol/L;

and placing the obtained product in a high-temperature deposition furnace after ultrasonic drying for deposition of the carbon nanowires to obtain a four-level blank.

The carbon nanowire deposition process comprises the following steps: and (3) depositing by adopting a bubbling method, wherein the carrier gas is nitrogen, the deposition precursor solution is acetone, the deposition temperature is 900-1300 ℃, the deposition pressure is 1000-1500 Pa, and the deposition time is 5-10 hours.

Step 6 is as follows: embedding the four-level blank by silicon powder, and then placing the four-level blank in a high-temperature furnace for hole sealing coating preparation, wherein the melting siliconizing temperature is 1300-1600 ℃, the constant temperature time is 1-3 hours, and the heating rate is 5-10 ℃/min.

The multilayer ceramic matrix composite material prepared by the method of the technical scheme.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

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

(1) the ceramic matrix composite prepared by the invention has a multilayer structure, and cracks can deflect among different layers in the loading process of the material, so that the diffusion energy is consumed, and the mechanical property of the composite is further improved.

(2) The composite interface of the pyrolytic carbon and the SiC nanowires is introduced at the joint of the fibers and the matrix, the pyrolytic carbon interface has a layered structure, so that cracks can deflect in the interface layer, in addition, the bonding force between the pyrolytic carbon interface layer and the fibers is moderate, the fibers can be pulled out, the specific surface area of the fiber surface is increased due to the introduction of the SiC nanowires, the wettability between the fiber surface and a precursor solution is improved, the dipping effect is improved, the micro pores remained in the dipping process are reduced, the effect of transferring load from the matrix to the fibers is also improved due to the introduction of the SiC nanowires, and the bearing effect of the fibers is exerted to a greater extent.

(3) The invention adopts polyborosilazane precursor to introduce SiBCN matrix into the material, the matrix is not crystallized and not decomposed at more than 1500 ℃, and the excellent oxidation resistance can be still maintained.

(4) In the invention, the SiC matrix is prepared by adopting a chemical vapor deposition process in the step 4, the SiC matrix has higher modulus, the mechanical behavior of the composite material can be improved, the SiC matrix is pre-oxidized after being deposited, and the SiC is oxidized to generate glassy SiO₂The cracks can be actively filled through the fluidity of the composite material, and the internal porosity of the composite material is further reduced.

(5) According to the invention, the carbon nanowires are introduced in the step 5, the one-dimensional nano material can form a three-dimensional network in the composite material, the mechanical property of the material is improved by breaking, crosslinking and pulling out the nanowires, the multi-scale toughening is realized, and in addition, the silicon carbide nanowires generated in situ by the reaction of the carbon nanowires and the silicon powder at a high temperature can also enhance the binding property between the SiC matrix and the hole sealing coating.

(6) According to the invention, the SiC hole sealing coating is prepared on the outer surface of the material through a siliconizing process, and the SiC prepared by the process has higher crystallinity, so that the corrosion resistance and ablation resistance of the surface of the composite material are improved.

Drawings

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

Detailed Description

In the following, with reference to fig. 1 in the embodiment of the present invention, a clear and complete description will be made of the technical solutions in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all 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.

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

The invention provides a preparation method of a multilayer ceramic matrix composite for an aeroengine thermal structure member, which comprises the following steps:

step 1: preparing a fiber preform by using continuous fibers as a toughening phase, wherein the preform structure is any one of a layer stitching structure, a three-dimensional weaving structure, a 2.5D structure and the like, the continuous fibers are silicon carbide fibers, and the volume fraction of the fibers in the preform is 30-45%; step 2: depositing on the surface of the fiber in the fiber preform by adopting a chemical vapor deposition process to obtain a pyrolytic carbon and SiC nanowire composite interface to obtain a primary blank; and step 3: rapidly densifying the product obtained in the step (2) by adopting a vacuum-pressurization impregnation process to obtain a secondary blank; and 4, step 4: filling the secondary blank with a matrix by adopting a chemical vapor deposition process, and pre-oxidizing to obtain a tertiary blank; and 5: introducing a pyrolytic carbon layer into the three-level blank by adopting a chemical vapor deposition process until the density of the blank introduced with the pyrolytic carbon layer reaches 1.9-2.0 g/cm³Then, introducing the carbon nano wire by a catalyst assisted deposition method to obtain a four-level blank; step 6: and preparing the SiC hole sealing coating on the surface of the four-level blank by a reaction melting siliconizing method.

In a further embodiment of the invention, the step 2 specifically comprises the step of preparing a pyrolytic carbon and SiC nanowire composite interface on the surface of the fiber inside the preform, wherein the pyrolytic carbon interface is prepared by placing the preform in pyrolytic carbon deposition equipment, using propane as deposition gas and nitrogen as dilution gas, the deposition temperature is 700-1000 ℃, the deposition time is 1-5 h, and the deposition pressure is 800-1500 Pa, wherein the flow rate of propane is 50-150 g/h, and the flow rate of nitrogen is 100-200 mL/min. The SiC nanowire is deposited on the surface of the pyrolytic carbon interface, and the deposition process of the SiC nanowire comprises the following steps: and placing the preform deposited with the pyrolytic carbon interface in an ethanol solution containing nickel chloride for ultrasonic treatment, wherein the concentration of the ethanol solution of the nickel chloride is 0.2-1 mol/L, and the ultrasonic treatment time is 3-5 hours. After the ultrasonic treatment is finished, the SiC nanowire is placed in a SiC deposition furnace for deposition, trichloromethyl silane is used as precursor gas, hydrogen is used as reducing gas, argon is used as diluting gas for deposition of the SiC nanowire, the deposition temperature is 800-1200 ℃, the deposition time is 1-5 h, the deposition pressure is 500-1500 Pa, and the trichloromethyl silane: hydrogen gas: the carrier gas flow ratio was 1:30: 30.

In a further embodiment of the present invention, the step 3 specifically includes using polyborosilazane as a precursor, placing the primary blank in an immersion device, and evacuating to the internal pressure of the device<Adding polyborosilazane precursor solution into impregnation equipment at 50Pa, introducing inert gas into the impregnation equipment for pressurization to 1-3 MPa after the mass fraction of the polyborosilazane in the precursor solution is 10-30% and the vacuum state is maintained for 1-2 hours, drying the impregnated primary blank and then putting the dried blank into a pyrolysis furnace for pyrolysis after the pressure is maintained for 1-2 hours, wherein the pyrolysis temperature is 900-1300 ℃, the constant temperature time is 1-2 hours, the heating rate is 3-5 ℃/min, repeating the impregnation-pyrolysis process until the overall density of the blank reaches 1.3-1.5 g/cm after the densification process, and the overall density of the blank reaches 1.3-1.5 g/cm³。

In a further embodiment of the present invention, the step 4 specifically includes performing matrix filling on the secondary green body by using a chemical vapor deposition process, wherein the deposition gas is trichloromethylsilane, the carrier gas is hydrogen, and the diluent gas is argon, performing deposition on the SiC matrix, the deposition temperature is 700 to 1100 ℃, the deposition time is 50 to 100 hours, the deposition pressure is 1000 to 2000Pa, and the deposition is performed until the density reaches 1.7 to 1.8g/cm³And then, pre-oxidizing the blank body in static air at the pre-oxidation temperature of 900-1300 ℃ for 1-5 hours to obtain a three-level blank body.

In a further embodiment of the invention, the step 5 specifically includes placing the three-stage blank in a pyrolytic carbon infiltration device, and performing pyrolytic carbon matrix infiltration by using natural gas as an infiltration gas and nitrogen as a diluent gas, wherein the infiltration temperature is 700-1100 ℃, the infiltration time is 50-100 h, the infiltration pressure is 1000-1500 Pa, and the infiltration is performed until the density reaches 1.9-2.0 g/cm³Then the blank is taken out and placed in cobalt acetateCarrying out ultrasonic treatment in an ethanol solution, wherein the concentration of the ethanol solution of cobalt acetate is 0.1-0.5 mol/L, carrying out ultrasonic drying, and then placing in a high-temperature deposition furnace for deposition of carbon nanowires, wherein the carbon nanowire deposition process comprises the following steps: and (3) depositing by adopting a bubbling method, wherein the carrier gas is nitrogen, the deposition precursor solution is acetone, the deposition temperature is 900-1300 ℃, the deposition pressure is 1000-1500 Pa, and the deposition time is 5-10 hours.

In a further embodiment of the invention, the step 6 specifically includes embedding the four-stage preform with silicon powder, and then placing the embedded four-stage preform in a high temperature furnace to prepare the hole sealing coating, wherein the reaction melting siliconizing temperature is 1300-1600 ℃, the constant temperature time is 1-3 hours, and the temperature rise rate is 5-10 ℃/min.

Example 1

The invention provides a preparation method of a multilayer ceramic matrix composite for an aeroengine thermal structure member, which comprises the following steps:

step 1: preparing a fiber preform by using continuous fibers as a toughening phase, wherein the structure of the preform is formed by paving and sewing, the continuous fibers are silicon carbide fibers, and the volume fraction of the fibers in the preform is 45%;

step 2: depositing on the surface of the fiber in the fiber preform by adopting a chemical vapor deposition process to obtain a pyrolytic carbon and SiC nanowire composite interface to obtain a primary blank; the preparation method of the pyrolytic carbon interface comprises the steps of placing a prefabricated body in pyrolytic carbon deposition equipment, taking propane as deposition gas and nitrogen as diluent gas, wherein the deposition temperature is 700 ℃, the deposition time is 5h, and the deposition pressure is 1200Pa, the propane flow is 50g/h, and the nitrogen flow is 100 mL/min. The SiC nanowire is deposited on the surface of the pyrolytic carbon interface, and the deposition process of the SiC nanowire comprises the following steps: and placing the preform deposited with the pyrolytic carbon interface in an ethanol solution containing nickel chloride for ultrasonic treatment, wherein the concentration of the ethanol solution of the nickel chloride is 0.2mol/L, and the ultrasonic treatment time is 3 hours. After the ultrasonic treatment is finished, the SiC nanowire is placed in a SiC deposition furnace for deposition, trichloromethylsilane is used as precursor gas, hydrogen is used as reducing gas, argon is used as diluting gas for deposition of the SiC nanowire, the deposition temperature is 1000 ℃, the deposition time is 3h, the deposition pressure is 1000Pa, and the trichloromethylsilane: hydrogen gas: the carrier gas flow ratio was 1:30: 30.

And step 3: rapidly densifying the product obtained in the step (2) by adopting a vacuum-pressurization impregnation process to obtain a secondary blank; placing a primary blank body in dipping equipment by taking polyborosilazane as a precursor, vacuumizing until the internal pressure of the equipment reaches 20Pa, adding polyborosilazane precursor solution into the dipping equipment, taking dimethylbenzene in the polyborosilazane precursor solution as a solvent, keeping the mass fraction of the polyborosilazane in the precursor solution at 15%, keeping the vacuum state for 2 hours, introducing inert gas into the dipping equipment for pressurization, pressurizing to 3MPa, keeping the pressure for 2 hours, drying the dipped primary blank body, then placing the dipped primary blank body in a cracking furnace for high-temperature cracking, wherein the cracking temperature is 900 ℃, the constant-temperature time is 1 hour, the heating rate is 3 ℃/min, and repeating the dipping-cracking process until the density reaches 1.3g/cm³。

And 4, step 4: filling the secondary blank with a matrix by adopting a chemical vapor deposition process, and pre-oxidizing to obtain a tertiary blank; carrying out matrix filling on the secondary blank by adopting a chemical vapor infiltration process, wherein the infiltration gas is trichloromethyl silane, the carrier gas is hydrogen, and the diluent gas is argon, carrying out infiltration on the SiC matrix, wherein the infiltration temperature is 900 ℃, the deposition infiltration time is 80h, the deposition infiltration time is 1500Pa, and the infiltration time is up to 1.8g/cm³And then placing the material in static air for pre-oxidation at 1100 ℃ for 3 hours.

And 5: introducing a pyrolytic carbon layer into the three-level blank by adopting a chemical vapor deposition process until the density reaches 2.0g/cm³Then, introducing the carbon nano wire by a catalyst assisted deposition method to obtain a four-level blank; putting the three-level blank body in a pyrolytic carbon infiltration device, carrying out pyrolytic carbon matrix infiltration by taking natural gas as infiltration gas and nitrogen as diluent gas, wherein the infiltration temperature is 1000 ℃, the infiltration time is 50h, the infiltration pressure is 1000Pa, and the infiltration is carried out until the density reaches 2.0g/cm³Then taking out the blank, placing the blank in an ethanol solution of cobalt acetate for ultrasonic treatment, wherein the concentration of the ethanol solution of cobalt acetate is 0.5mol/L, placing the blank in a high-temperature deposition furnace for carbon nanowire after ultrasonic dryingThe carbon nanowire deposition process comprises the following steps: and (3) carrying out deposition by adopting a bubbling method, wherein the carrier gas is nitrogen, the deposition precursor solution is acetone, the deposition temperature is 1300 ℃, the deposition pressure is 1200Pa, and the deposition time is 5 hours.

Step 6: and preparing the SiC hole sealing coating on the surface of the four-level blank by a reaction melting siliconizing method. Embedding the four-level preform by using silicon powder, and then placing the four-level preform in a high-temperature furnace for hole sealing coating preparation, wherein the reaction melting siliconizing temperature is 1600 ℃, the constant temperature time is 3 hours, and the heating rate is 5 ℃/min.

The porosity of the ceramic matrix composite prepared by the traditional process is more than 5%, the porosity of the multilayer ceramic matrix composite prepared by the embodiment is not more than 2.0%, the room-temperature bending strength is at least 545MPa, and the strength retention rate is more than 90% after the multilayer ceramic matrix composite is oxidized at 1400 ℃ for 200 hours.

Example 2

The invention provides a preparation method of a multilayer ceramic matrix composite for an aeroengine thermal structure member, which comprises the following steps:

step 1: preparing a fiber preform by using continuous fibers as a toughening phase, wherein the preform structure is a three-dimensional woven structure, the continuous fibers are silicon carbide fibers, and the volume fraction of the fibers in the preform is 40%;

step 2: depositing on the surface of the fiber in the fiber preform by adopting a chemical vapor deposition process to obtain a pyrolytic carbon and SiC nanowire composite interface to obtain a primary blank; the preparation method of the pyrolytic carbon interface comprises the steps of placing a prefabricated body in pyrolytic carbon deposition equipment, taking propane as deposition gas, taking nitrogen as diluent gas, setting the deposition temperature at 800 ℃, setting the deposition time at 3.5h and setting the deposition pressure at 1200Pa, wherein the flow rate of propane is 80g/h, and the flow rate of nitrogen is 100 mL/min. The SiC nanowire is deposited on the surface of the pyrolytic carbon interface, and the deposition process of the SiC nanowire comprises the following steps: and placing the preform deposited with the pyrolytic carbon interface in an ethanol solution containing nickel chloride for ultrasonic treatment, wherein the concentration of the ethanol solution of the nickel chloride is 0.5mol/L, and the ultrasonic treatment time is 3 hours. After the ultrasonic treatment is finished, the SiC nanowire is placed in a SiC deposition furnace for deposition, trichloromethylsilane is used as precursor gas, hydrogen is used as reducing gas, argon is used as diluting gas for deposition of the SiC nanowire, the deposition temperature is 1000 ℃, the deposition time is 3h, the deposition pressure is 1000Pa, and the trichloromethylsilane: hydrogen gas: the carrier gas flow ratio was 1:30: 30.

And step 3: rapidly densifying the product obtained in the step (2) by adopting a vacuum-pressurization impregnation process to obtain a secondary blank; placing a primary blank body in dipping equipment by taking polyborosilazane as a precursor, vacuumizing until the internal pressure of the equipment reaches 20Pa, adding polyborosilazane precursor solution into the dipping equipment, taking dimethylbenzene in the polyborosilazane precursor solution as a solvent, keeping the mass fraction of the polyborosilazane in the precursor solution at 15%, keeping the vacuum state for 2 hours, introducing inert gas into the dipping equipment for pressurization, pressurizing to 3MPa, keeping the pressure for 2 hours, drying the dipped primary blank body, then placing the dipped primary blank body in a cracking furnace for high-temperature cracking, wherein the cracking temperature is 1000 ℃, the constant-temperature time is 1 hour, the heating rate is 3 ℃/min, and repeating the dipping-cracking process until the density reaches 1.4g/cm³。

And 4, step 4: filling the secondary blank with a matrix by adopting a chemical vapor deposition process, and pre-oxidizing to obtain a tertiary blank; filling a substrate into the secondary blank by adopting a chemical vapor infiltration process, wherein the infiltration gas is trichloromethylsilane, the carrier gas is hydrogen, and the diluent gas is argon, carrying out infiltration on the SiC substrate, the infiltration deposition temperature is 1000 ℃, the infiltration time is 80h, the infiltration pressure is 1500Pa, and the infiltration is carried out until the density reaches 1.75g/cm³And then placing the material in static air for pre-oxidation at 1100 ℃ for 3 hours.

And 5: introducing a pyrolytic carbon layer into the three-level blank by adopting a chemical vapor deposition process until the density reaches 1.9g/cm³Then, introducing the carbon nano wire by a catalyst assisted deposition method to obtain a four-level blank; putting the three-level blank body in a pyrolytic carbon infiltration device, carrying out pyrolytic carbon matrix infiltration by taking natural gas as infiltration gas and nitrogen as diluent gas, wherein the infiltration temperature is 1000 ℃, the infiltration time is 50h, the infiltration pressure is 1000Pa, and the infiltration is carried out until the density reaches 1.9g/cm³Then taking out the blank and putting the blank into an ethanol solution of cobalt acetatePerforming ultrasonic treatment, wherein the concentration of the ethanol solution of the cobalt acetate is 0.5mol/L, performing ultrasonic drying, and then placing the dried cobalt acetate in a high-temperature deposition furnace for deposition of carbon nanowires, wherein the carbon nanowire deposition process comprises the following steps: and (3) carrying out deposition by adopting a bubbling method, wherein the carrier gas is nitrogen, the deposition precursor solution is acetone, the deposition temperature is 1300 ℃, the deposition pressure is 1200Pa, and the deposition time is 7 hours.

Step 6: and preparing the SiC hole sealing coating on the surface of the four-level blank by a reaction melting siliconizing method. Embedding the four-level preform by using silicon powder, and then placing the four-level preform in a high-temperature furnace for hole sealing coating preparation, wherein the reaction melting siliconizing temperature is 1600 ℃, the constant temperature time is 3 hours, and the heating rate is 8 ℃/min.

The porosity of the ceramic matrix composite prepared by the traditional process is more than 5%, the porosity of the multilayer ceramic matrix composite prepared by the embodiment is not more than 1.6%, the room-temperature bending strength is at least 635MPa, and the strength retention rate after the ceramic matrix composite is oxidized at 1400 ℃ for 200 hours is more than 95%.

Example 3

The invention provides a preparation method of a multilayer ceramic matrix composite for an aeroengine thermal structure member, which comprises the following steps:

step 1: preparing a fiber preform by using continuous fibers as a toughening phase, wherein the preform structure is a 2.5D structure, the continuous fibers are silicon carbide fibers, and the volume fraction of the fibers in the preform is 30%;

step 2: depositing on the surface of the fiber in the fiber preform by adopting a chemical vapor deposition process to obtain a pyrolytic carbon and SiC nanowire composite interface to obtain a primary blank; the preparation method of the pyrolytic carbon interface comprises the steps of placing a prefabricated body in pyrolytic carbon deposition equipment, taking propane as deposition gas and nitrogen as diluent gas, wherein the deposition temperature is 1000 ℃, the deposition time is 1h, and the deposition pressure is 1200Pa, the propane flow is 150g/h, and the nitrogen flow is 100 mL/min. The SiC nanowire is deposited on the surface of the pyrolytic carbon interface, and the deposition process of the SiC nanowire comprises the following steps: and placing the preform deposited with the pyrolytic carbon interface in an ethanol solution containing nickel chloride for ultrasonic treatment, wherein the concentration of the ethanol solution of the nickel chloride is 1mol/L, and the ultrasonic treatment time is 3 hours. After the ultrasonic treatment is finished, the SiC nanowire is placed in a SiC deposition furnace for deposition, trichloromethylsilane is used as precursor gas, hydrogen is used as reducing gas, argon is used as diluting gas for deposition of the SiC nanowire, the deposition temperature is 1000 ℃, the deposition time is 3h, the deposition pressure is 1000Pa, and the trichloromethylsilane: hydrogen gas: the carrier gas flow ratio was 1:30: 30.

And step 3: rapidly densifying the product obtained in the step (2) by adopting a vacuum-pressurization impregnation process to obtain a secondary blank; placing a primary blank body in dipping equipment by taking polyborosilazane as a precursor, vacuumizing until the internal pressure of the dipping equipment reaches 20Pa, adding polyborosilazane precursor solution into the dipping equipment, taking dimethylbenzene in the polyborosilazane precursor solution as a solvent, keeping the mass fraction of the polyborosilazane in the precursor solution at 15%, keeping the vacuum state for 2 hours, introducing inert gas into the equipment for pressurization, pressurizing to 3MPa, keeping the pressure for 2 hours, drying the dipped primary blank body, then placing the dipped primary blank body in a cracking furnace for high-temperature cracking, keeping the cracking temperature at 1200 ℃, keeping the constant temperature for 1 hour, heating the temperature at 3 ℃/min, and repeating the dipping-cracking process until the density reaches 1.5g/cm³。

And 4, step 4: filling the secondary blank with a matrix by adopting a chemical vapor deposition process, and pre-oxidizing to obtain a tertiary blank; carrying out matrix filling on the secondary blank by adopting a chemical vapor infiltration process, wherein the infiltration gas is trichloromethyl silane, the carrier gas is hydrogen, and the diluent gas is argon, carrying out infiltration on the SiC matrix, the infiltration temperature is 1100 ℃, the infiltration time is 80h, the infiltration pressure is 1500Pa, and the infiltration is carried out until the density reaches 1.7g/cm³And then placing the material in static air for pre-oxidation at 1100 ℃ for 3 hours.

And 5: introducing a pyrolytic carbon layer into the three-level blank by adopting a chemical vapor deposition process until the density reaches 2.0g/cm³Then, introducing the carbon nano wire by a catalyst assisted deposition method to obtain a four-level blank; putting the three-level blank body in a pyrolytic carbon infiltration device, carrying out pyrolytic carbon matrix infiltration by taking natural gas as infiltration gas and nitrogen as diluent gas, wherein the infiltration temperature is 1000 ℃, the infiltration time is 50h, and the infiltration pressure isThe force is 1000Pa, and the infiltration is carried out until the density reaches 2.0g/cm³Then taking out the material, placing the material in an ethanol solution of cobalt acetate for ultrasonic treatment, wherein the concentration of the ethanol solution of cobalt acetate is 0.5mol/L, placing the material in a high-temperature deposition furnace for deposition of carbon nanowires after ultrasonic drying, and the deposition process of the carbon nanowires comprises the following steps: and (3) carrying out deposition by adopting a bubbling method, wherein the carrier gas is nitrogen, the deposition precursor solution is acetone, the deposition temperature is 1300 ℃, the deposition pressure is 1200Pa, and the deposition time is 10 hours.

Step 6: and preparing the SiC hole sealing coating on the surface of the four-level blank by a reaction melting siliconizing method. Embedding the four-level preform by using silicon powder, and then placing the four-level preform in a high-temperature furnace for hole sealing coating preparation, wherein the reaction melting siliconizing temperature is 1600 ℃, the constant temperature time is 3 hours, and the heating rate is 10 ℃/min.

The porosity of the ceramic matrix composite prepared by the traditional process is more than 5%, the porosity of the multilayer ceramic matrix composite prepared by the embodiment is 2.4%, the room-temperature bending strength is 504MPa, and the strength retention rate after the multilayer ceramic matrix composite is oxidized at 1400 ℃ for 200 hours is more than 85%.