C / sic foam framework reinforced sic / al2o3 ceramic matrix composite material and preparation method thereof

Abstract

The present application relates to the technical field of ceramic matrix composite, more particularly, to C / SiC foam framework reinforced SiC / Al2O3 ceramic matrix composite and a preparation method thereof.The present application adopts lightweight and high-strength C foam as the framework material of aerogel composite material, and realizes mechanical modification and reinforcement of the C foam framework through a SiC coating layer, the SiC / Al2O3 ceramic matrix composite is obtained through a precursor impregnation pyrolysis process, through the alternative structure design of SiC and Al2O3 ceramic matrix, the mutual embedding and interlocking of SiC and Al2O3 ceramic matrix are realized, and the addition of the Al2O3 ceramic matrix greatly promotes the high-temperature resistance and oxidation resistance of the C / SiC foam framework reinforced SiC / Al2O3 ceramic matrix composite, which is conducive to its further application in a high-temperature aerobic environment.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and more specifically, to a C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material and its preparation method. Background Technology

[0002] With the increasing complexity of the current electromagnetic environment, the performance indicators of a single material are insufficient to meet the demands for high-quality materials and diversified performance. For traditional ceramic materials, stealth and wave transmission properties are contradictory. Meeting stealth requirements inevitably sacrifices overall wave transmission performance to some extent, while ensuring wave transmission performance reduces stealth. This is especially true with the rapid development of radar communication technology, which places extremely stringent demands on the performance of fairings under various operating conditions. Therefore, exploring new material systems and preparation processes, leveraging the complementary advantages of different material components to synergistically improve overall load-bearing capacity, stealth, and wave transmission performance, and developing key technologies for the preparation, installation, and evaluation of multifunctional ceramic matrix composites are the future development direction for novel ceramic materials.

[0003] Chinese invention patent application number CN201611182773.1 discloses a SiC ceramic matrix composite component and its preparation method. The SiC ceramic matrix composite component includes multiple SiC ceramic matrix composite connected parts, which are connected to each other by a connecting layer located at the joint. The connecting layer is formed by vapor-phase silica infiltration and sintering of a mixed slurry, which includes carbon black, α-SiC ceramic powder and a dispersant. The preparation method of the SiC ceramic matrix composite component includes the following steps: (1) preparation of the mixed slurry; (2) pre-connection; (3) vapor-phase silica infiltration and sintering. The SiC ceramic matrix composite component has low porosity at the joint interface, high joint strength, stability and reliability and high temperature resistance; good chemical and mechanical compatibility and structural integrity between the connected parts and the connecting layer; the preparation method has the advantages of high connection strength, simple operation, low process requirements and adaptability to the connection of SiC ceramic matrix composites after silica infiltration.

[0004] Chinese invention patent application CN202011322696.1 discloses a method for preparing Hf-Ta-C reinforced C / SiC ceramic matrix composite material. The preparation method includes the following steps: (1) providing a carbon / carbon matrix; (2) using a silicon alloy as a reactant, reacting the carbon / carbon matrix to form a C / SiC ceramic matrix composite material using a reactive melting method; (3) using a hafnium-tantalum precursor solution as a reactant, reacting it with the C / SiC ceramic matrix composite material using an impregnation pyrolysis method to obtain the Hf-Ta-C reinforced C / SiC ceramic matrix composite material. This preparation method fully utilizes the high efficiency advantage of the reactive melting method and, with the help of the impregnation pyrolysis method, further reduces the porosity and ablation resistance of the composite material, thereby effectively solving the problem of poor ablation resistance caused by the large number of pores in the C / SiC ceramic matrix composite material.

[0005] Chinese invention patent application number CN201810073219.2 discloses a SiC w A method for preparing SiC / SiC ceramic matrix composites is disclosed. The purpose of this invention is to address the problems of high porosity and brittleness in 3D-printed ceramic specimens after post-processing. The method involves mixing SiC powder and binder powder to obtain a ceramic green body, and then drawing the SiC... W A three-dimensional model of the SiC / SiC ceramic matrix composite was created, and the parameters for a 3D printer were set. Then, a high-temperature debinding process was performed, followed by repeated impregnation and pyrolysis until no further weight gain was observed. This invention achieves both densification and toughening effects, with a porosity of only 8.5%, thus improving the strength and toughness of the ceramic matrix composite.

[0006] Chinese invention patent application CN117659412A discloses a low-cost liquid SiC precursor for SiC ceramic matrix composites and its preparation method. The preparation method includes using phenyldichlorosilane and dihaloalkanes as monomers, undergoing a dechlorination polymerization reaction under the action of alkali metals, followed by reaction with chlorosilanes and alcohols to increase its molecular weight and branching degree, and finally removing the solvent by vacuum distillation to obtain the liquid SiC precursor. This invention uses simple reaction steps to prepare a liquid SiC precursor, resulting in low cost and excellent product performance, making it suitable for the preparation of SiC ceramic matrix composites.

[0007] Chinese invention patent application number CN117534495A discloses a method for preparing ceramic matrix composites by precursor impregnation pyrolysis combined with reactive melt infiltration. The method uses BCl3 and NH3 as raw materials in SiC... nf SiC powder was prepared by coating the surface with a BN interfacial coating and obtaining an ethanol dispersion, mixing SiC powder, polyethylene glycol and ethanol dispersant, drying, and pressing into shape. nf / SiC preform; porous SiC was prepared using polycarbosilane as a precursor via a precursor impregnation pyrolysis process. nf / SiC ceramics; a porous ceramic preform filled with carbon is prepared by impregnation and pyrolysis of phenolic resin, and finally densified by silicon reactive infiltration. This invention combines two processes to form a bicontinuous phase of silicon carbide and silicon, which improves the service temperature and strength of the ceramic matrix composite material. At the same time, it avoids the shortcomings of high porosity and low strength of composite materials prepared by precursor impregnation and pyrolysis, and improves the density and strength of the composite material by silicon reactive infiltration.

[0008] As shown in the above patents, they all disclose a ceramic matrix composite material, but the integrated structure and performance design of load-bearing, stealth and wave transmission are not achieved in the preparation process, making it difficult to effectively achieve the expected goals. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0010] A C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material, comprising C foam, a SiC coating, and a SiC / Al2O3 ceramic matrix, wherein the density of the ceramic matrix composite material is 2.4-3.0 g / cm³. 3 Room temperature flexural strength 60-100 MPa, room temperature tensile strength 60-100 MPa, tensile modulus 80-120 GPa, interlaminar shear strength 5.0-10 MPa, room temperature fracture toughness 5-8 MPa . m 1 / 2 The mass loss rate at 1200℃ / 10h is 0.5-1.0%, and the mechanical property retention rate is 80-85%.

[0011] The C foam is obtained through a high-temperature pyrolysis process, with a porosity of 70-90% and a density of 0.15-0.35 g / cm³. 3 Young's modulus 0.5-2.0 GPa, shear strength 1.0-2.5 MPa, thermal conductivity 0.1-0.2 W / (m²) . K);

[0012] The SiC coating is obtained by chemical vapor deposition and is uniformly coated on the surface of the C foam skeleton in a continuous structure. The SiC coating thickness is 0.1-0.3 μm, forming a double network structure with the C foam.

[0013] The SiC / Al2O3 ceramic matrix is ​​obtained by polymer precursor impregnation and pyrolysis process. The SiC and Al2O3 ceramic matrices are alternately filled in the pores of the C / SiC foam skeleton. The porosity of the SiC / Al2O3 ceramic matrix is ​​0.5-1.0%, and the average pore size is 5-10 nm.

[0014] The C-foam has an open-cell interconnected structure with a gradient distribution along the central direction. The porosity of the outermost layer is 85-90%, and the porosity of the center is 70-75%.

[0015] The C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material is characterized in that: the SiC coating and the C foam form a double network structure;

[0016] A method for preparing a C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material, characterized by comprising the following steps:

[0017] S1: Cut melamine foam to a certain size, first heat it to 100-150℃ in a muffle furnace, hold it for 2-3 hours to remove surface impurities and unreacted matrix, then place it in a high-temperature pyrolysis furnace, introduce nitrogen to maintain an inert atmosphere, set the temperature rise rate to 1-2℃ / min, the temperature to 900-1000℃, hold it for 2-3 hours, and cool it with the furnace to obtain C foam;

[0018] S2: Place C foam in a chemical vapor deposition furnace, introduce hydrogen, trimethylsilane and argon, set the gas flow rate ratio to 150-180:20-30:150-180sccm, set the reaction time to 2-4h, and obtain C / SiC foam with uniform SiC coating.

[0019] S3: Polycarbosilane was selected as the solute and xylene as the solvent. After stirring at 30°C for 30-45 min to obtain a uniformly mixed precursor organic sol solution, the cut C / SiC foam was placed at the bottom of a polytetrafluoroethylene beaker mold in advance. Then, the precursor organic sol solution was poured into the polytetrafluoroethylene beaker mold and subjected to negative pressure treatment. Then, it was placed in an oven at 60-70°C for 12-24 h for sol-gel reaction. After that, it was aged in an oven at 100-120°C for 12-24 h to obtain C / SiC foam-reinforced SiC precursor organic wet gel.

[0020] S4: Place the C / SiC foam-reinforced SiC precursor organic wet gel in a high-temperature tube furnace, heat it to 1300-1500℃ under nitrogen atmosphere protection and hold it for 1-2 hours. The heating rate is 3-5℃ / min and the nitrogen flow rate is 50-70.00ml / min to obtain C / SiC foam-reinforced SiC ceramic matrix composite material.

[0021] S5: The C / SiC foam-reinforced SiC ceramic matrix composite material was placed in a mixed solution of isopropanol / aluminum isopropoxide and subjected to negative pressure treatment. Then, it was placed in an oven at 60-70℃ for 12-24h sol-gel reaction and then aged in an oven at 100-120℃. After 12-24h, the C / SiC foam-reinforced SiC ceramic / Al2O3 precursor organic wet gel was obtained.

[0022] S6: Place the C / SiC foam-reinforced SiC ceramic / Al2O3 precursor organic wet gel in a high-temperature tube furnace, heat it to 800-900℃ under nitrogen atmosphere protection and hold it for 1-2 hours. The heating rate is 3-5℃ / min and the nitrogen flow rate is 50-70.00ml / min to obtain the C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material. Calculate the weight gain.

[0023] S7: Repeat steps S3-S6 until the weight gain rate is 1-2%, to obtain the desired C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material.

[0024] Compared with the prior art, the beneficial effects of this invention are:

[0025] 1. This invention uses lightweight and high-strength C foam as the skeleton material of ceramic matrix composites, and achieves mechanical modification and enhancement of the C foam skeleton through SiC coating. The SiC / Al2O ceramic matrix is ​​obtained through polymer precursor impregnation and pyrolysis process. The SiC and Al2O3 ceramic matrices fill the pores of the C / SiC foam skeleton in an alternating structure, realizing the interlocking of SiC and Al2O3 ceramic matrices, which greatly promotes the mechanical strength of ceramic matrix composites.

[0026] 2. This invention adopts a design scheme with a gradient distribution of C foam porosity, that is, the porosity of the outermost layer is 85-90%, and the porosity of the center is 70-75%. On the one hand, this allows the precursor organic sol liquid to enter the interior of the C foam skeleton pores more effectively. On the other hand, the porosity can be adjusted to regulate the proportion and densification degree of the SiC / Al2O ceramic matrix, thereby controlling the mechanical properties of C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composites.

[0027] 3. This invention adds an Al2O3 ceramic matrix to the original ceramic matrix composite material, which greatly promotes the high temperature resistance and oxidation resistance of the C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material, which is beneficial for its further application in high temperature and oxygen environment. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] A C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material, comprising C foam, SiC coating, and SiC / Al2O3 ceramic matrix, wherein the density of the ceramic matrix composite material is 2.50 g / cm³. 3 The room temperature flexural strength is 80 MPa, the room temperature tensile strength is 60 MPa, the tensile modulus is 90 GPa, the interlaminar shear strength is 6.0 MPa, and the room temperature fracture toughness is 6.0 MPa. . m 1 / 2 The mass loss rate at 1200℃ / 10h is 0.6%, and the mechanical property retention rate is 85%.

[0030] The C foam is obtained through a high-temperature pyrolysis process, with a porosity of 80% and a density of 0.25 g / cm³. 3 Young's modulus 1.0 GPa, shear strength 1.2 MPa, thermal conductivity 0.15 W / (m²) . K);

[0031] The SiC coating is obtained by chemical vapor deposition and is uniformly coated on the surface of the C foam skeleton in a continuous structure. The SiC coating thickness is 0.2 μm, forming a double network structure with the C foam.

[0032] The SiC / Al2O3 ceramic matrix is ​​obtained by polymer precursor impregnation and pyrolysis process. The SiC and Al2O3 ceramic matrices are alternately filled in the pores of the C / SiC foam skeleton. The porosity of the SiC / Al2O3 ceramic matrix is ​​1.0% and the average pore size is 6nm.

[0033] The C-foam has an open-cell interconnected structure, and is distributed in a gradient along the central direction of the aerogel. The porosity of the outermost layer is 90%, and the porosity of the center is 70%.

[0034] The C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material is characterized in that: the SiC coating and the C foam form a double network structure;

[0035] A method for preparing a C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material, characterized by comprising the following steps:

[0036] S1: Cut melamine foam to a certain size, first heat it to 100℃ in a muffle furnace, hold it for 2 hours to remove surface impurities and unreacted matrix, then place it in a high-temperature pyrolysis furnace, introduce nitrogen to maintain an inert atmosphere, set the temperature rise rate to 1℃ / min, the temperature to 900℃, hold it for 2 hours, and cool it with the furnace to obtain C foam.

[0037] S2: Place C foam in a chemical vapor deposition furnace, introduce hydrogen, trimethylsilane and argon, set the gas flow rate ratio to 160:25:160 sccm, set the reaction time to 2h, and obtain C / SiC foam with uniform SiC coating.

[0038] S3: Polycarbosilane was selected as the solute and xylene as the solvent. After stirring at 30°C for 35 min to obtain a uniformly mixed precursor organic sol solution, the cut C / SiC foam was placed at the bottom of a polytetrafluoroethylene beaker mold in advance. Then, the precursor organic sol solution was poured into the polytetrafluoroethylene beaker mold and subjected to negative pressure treatment. Then, it was placed in a 65°C oven for 18 h of sol-gel reaction. After that, it was aged in a 100°C oven. After 18 h, C / SiC foam-reinforced SiC precursor organic wet gel was obtained.

[0039] S4: The C / SiC foam-reinforced SiC precursor organic wet gel was placed in a high-temperature tube furnace, heated to 1400℃ and held for 2 hours under nitrogen atmosphere protection. The heating rate was 3.5℃ / min and the nitrogen flow rate was 50ml / min to obtain the C / SiC foam-reinforced SiC ceramic matrix composite material.

[0040] S5: The C / SiC foam-reinforced SiC ceramic matrix composite material was placed in a mixed solution of isopropanol / aluminum isopropoxide and subjected to negative pressure treatment. Then it was placed in a 60℃ oven for 18h sol-gel reaction and then aged in a 100℃ oven. After 18h, C / SiC foam-reinforced SiC ceramic / Al2O3 precursor organic wet gel was obtained.

[0041] S6: The C / SiC foam-reinforced SiC ceramic / Al2O3 precursor organic wet gel was placed in a high-temperature tube furnace and heated to 800℃ under nitrogen atmosphere protection and held for 1.5h. The heating rate was 3.5℃ / min and the nitrogen flow rate was 50.00ml / min to obtain the C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material. The weight gain was calculated.

[0042] S7: Repeat steps S3-S6 until the weight gain rate is 1%, to obtain the desired C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material.

[0043] The above description only illustrates the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material, comprising C foam, a SiC coating, and a SiC / Al2O3 ceramic matrix, wherein the density of the ceramic matrix composite material is 2.4-3.0 g / cm³. 3 Room temperature flexural strength 60-100 MPa, room temperature tensile strength 60-100 MPa, tensile modulus 80-120 GPa, interlaminar shear strength 5-10 MPa, room temperature fracture toughness 5-8 MPa . m 1 / 2 The mass loss rate at 1200℃ / 10h is 0.5-1.0%, and the mechanical property retention rate is 80-85%. The C foam is obtained through a high-temperature pyrolysis process, with a porosity of 70-90% and a density of 0.15-0.35 g / cm³. 3 Young's modulus 0.5-2.0 GPa, shear strength 1.0-2.5 MPa, thermal conductivity 0.1-0.2 W / (m²) . K); The SiC coating is obtained through chemical vapor deposition and is uniformly coated on the surface of the C foam skeleton in a continuous structure. The SiC coating thickness is 0.1-0.3 μm, forming a double network structure with the C foam. The C foam has an open-cell interconnected structure with a gradient distribution along the central direction. The porosity of the outermost layer is 85-90%, and the porosity at the center is 70-75%. The SiC / Al2O3 ceramic matrix is ​​obtained by polymer precursor impregnation and pyrolysis process. The SiC and Al2O3 ceramic matrices are alternately filled in the pores of the C / SiC foam skeleton. The porosity of the SiC / Al2O3 ceramic matrix is ​​0.5-1.0%, and the average pore size is 5-10 nm.

2. A method for preparing the C / SiC foam skeleton reinforced SiC / Al2O3 ceramic matrix composite material according to claim 1, characterized in that, Includes the following steps: S1: Cut melamine foam to a certain size, first heat it to 100-150℃ in a muffle furnace, hold it for 2-3 hours to remove surface impurities and unreacted matrix, then place it in a high-temperature pyrolysis furnace, introduce nitrogen to maintain an inert atmosphere, set the temperature rise rate to 1-2℃ / min, the temperature to 900-1000℃, hold it for 2-3 hours, and cool it with the furnace to obtain C foam; S2: Place C foam in a chemical vapor deposition furnace, introduce hydrogen, trimethylsilane and argon, set the gas flow rate ratio to 150-180:20-30:150-180 sccm, set the reaction time to 2-4h, and obtain C / SiC foam with uniform SiC coating. S3: Polycarbosilane was selected as the solute and xylene as the solvent. After stirring at 30°C for 30-45 min to obtain a uniformly mixed precursor organic sol solution, the cut C / SiC foam was placed at the bottom of a polytetrafluoroethylene beaker mold in advance. Then, the precursor organic sol solution was poured into the polytetrafluoroethylene beaker mold and subjected to negative pressure treatment. Then, it was placed in an oven at 60-70°C for 12-24 h for sol-gel reaction. After that, it was aged in an oven at 100-120°C for 12-24 h to obtain C / SiC foam-reinforced SiC precursor organic wet gel. S4: Place the C / SiC foam-reinforced SiC precursor organic wet gel in a high-temperature tube furnace, heat it to 1300-1500℃ under nitrogen atmosphere protection and hold it for 1-2 hours. The heating rate is 3-5℃ / min and the nitrogen flow rate is 50-70.00ml / min to obtain C / SiC foam-reinforced SiC ceramic matrix composite material. S5: The C / SiC foam-reinforced SiC ceramic matrix composite material was placed in a mixed solution of isopropanol / aluminum isopropoxide and subjected to negative pressure treatment. Then, it was placed in an oven at 60-70℃ for 12-24h sol-gel reaction and then aged in an oven at 100-120℃. After 12-24h, the C / SiC foam-reinforced SiC ceramic / Al2O3 precursor organic wet gel was obtained. S6: Place the C / SiC foam-reinforced SiC ceramic / Al2O3 precursor organic wet gel in a high-temperature tube furnace, heat it to 800-900℃ under nitrogen atmosphere protection and hold it for 1-2 hours. The heating rate is 3-5℃ / min and the nitrogen flow rate is 50-70.00ml / min to obtain the C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material. Calculate the weight gain. S7: Repeat steps S3-S6 until the weight gain rate is 1-2%, to obtain the desired C / SiC foam-reinforced SiC / Al2O3 ceramic matrix composite material.