Basalt fiber reinforced ceramic matrix composite suitable for high temperature structures and method of making the same

Abstract

The application discloses basalt fiber reinforced ceramic matrix composite suitable for high-temperature structures and a preparation method thereof, and belongs to the technical field of composite material preparation. The preparation method comprises the following steps: first, weaving basalt fiber cloth to obtain a preform; then, preparing a boron nitride interface layer by CVD; then, preparing a slurry by taking a precursor, a powder material and a dispersion medium as raw materials, impregnating and drying the preform, and finally, performing sintering treatment and CVI to obtain the basalt fiber reinforced ceramic matrix composite. The basalt fiber cloth is woven into a preform, after the boron nitride interface layer is constructed, the preform is impregnated in a multiphase ceramic precursor slurry and sintered by increasing temperature, the interface layer, the fiber and the multiphase ceramic matrix are cooperatively constructed into a structure, the ceramic matrix composite with good thermal shock resistance and high-temperature bearing capacity is obtained, the demand of high-temperature structural members is met, and the problems of insufficient interface regulation of the basalt fiber reinforced ceramic matrix composite, poor high-temperature strength, toughness and thermal shock resistance and the like are solved.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to a basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures and its preparation method. Background Technology

[0002] Basalt fiber has attracted attention in the field of composite materials in recent years due to its excellent mechanical properties, high-temperature resistance, and abundant raw material resources. Current industrial applications mainly focus on resin-based basalt fiber composites, whose products are widely used in building reinforcement, transportation safety, and corrosion-resistant structural components. However, resin-based systems generally suffer from low thermal decomposition temperatures, rapid degradation of mechanical properties, and insufficient long-term thermal stability under high-temperature conditions, making it difficult to meet the requirements of high-temperature structural components. To enhance the application potential of basalt fiber in high-temperature fields, researchers have begun to explore its use in ceramic matrix composites (CMCs) to obtain higher heat resistance, ablation resistance, and fatigue resistance.

[0003] In the field of high-temperature composite materials, the current mainstream material is carbon fiber reinforced ceramic matrix composites, which can operate at temperatures exceeding 1000℃ and can be used in aerospace thermal protection, combustion chambers, and heat-resistant structures in power plants. However, high-performance carbon fibers are expensive, and carbon fiber composites are easily oxidized in air, requiring complex interface treatments and anti-oxidation coating systems. This results in numerous manufacturing processes and high costs, limiting its widespread adoption in more medium- and high-temperature structural applications. New material systems that can operate stably for extended periods in the 500-1000℃ range, while significantly reducing costs compared to carbon fiber composites, have significant engineering value.

[0004] In recent years, some technologies have attempted to use basalt fibers in ceramic matrix composites. For example, patent CN102701770A explored a method for preparing continuous basalt fiber reinforced ceramic composites, but its matrix system is relatively simple, the interface structure lacks effective control, and the material's thermal shock resistance and high-temperature cycling stability are insufficient. Patent CN112321312A proposed basalt fiber reinforced low-temperature co-fired ceramic composites, but its matrix has limited temperature resistance, and the fibers are prone to strength decay during high-temperature sintering.

[0005] On the other hand, compared with carbon fiber, basalt fiber has significant advantages in interface preparation. The surface of basalt fiber contains a high proportion of metal oxides, allowing for easy construction of the interface layer through impregnation, sol-gel, and precursor coating methods, resulting in simple and low-cost processes. Simultaneously, basalt fiber is not easily oxidized in air, greatly reducing complex anti-oxidation processes and making it easier to maintain fiber strength during composite material preparation. Furthermore, basalt fiber has achieved a high level of maturity in large-scale manufacturing and fabrication, significantly reducing the overall manufacturing cost of composite materials.

[0006] In summary, existing basalt fiber reinforced ceramic matrix composites generally suffer from the following technical shortcomings: insufficient interface control and lack of a stable, high-temperature resistant interface coating system, resulting in fiber damage during sintering or excessive / weak bonding with the matrix; relatively simple ceramic matrix system, making it difficult to balance high-temperature strength, toughness, and thermal shock resistance; and limited overall high-temperature resistance of the composite material, making it difficult to use in high-temperature structural fields for extended periods. Summary of the Invention

[0007] To address the problems of existing technologies, the present invention aims to provide a basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures and its preparation method, thereby solving the problems of insufficient interface control, lack of stable and high-temperature resistant interface coating system, resulting in fiber damage or excessive / weak bonding with the matrix during sintering; relatively simple ceramic matrix system, making it difficult to balance high-temperature strength, toughness, and thermal shock performance; and limited overall high-temperature resistance of the composite material, making it difficult to use in high-temperature structural fields for a long time.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides a method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures, comprising the following steps: S1. Weave basalt fiber cloth to obtain basalt fiber preform; S2. Using chemical vapor deposition, a boron nitride interface layer is deposited on the surface of the fiber preform obtained in S1 to obtain a basalt fiber preform coated with a boron nitride interface layer. S3. Mix the precursor polymer, powder material and dispersion medium to obtain ceramic precursor slurry; S4. The basalt fiber preform coated with boron nitride interface layer obtained in S2 is impregnated and dried in the ceramic precursor slurry obtained in S3 to obtain the impregnated preform. S5. The impregnated preform obtained in S4 is sintered to obtain a preliminary dense blank. S6. Chemical vapor infiltration is performed on the preliminary dense blank obtained in S5 to prepare a basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures. The precursor polymers in S3 include polycarbosilane, polyboronazine, and polysiloxane; the powder materials include SiC powder, Si3N4 powder, SiO2 powder, Al2O3 powder, ZrO2 powder, and BN powder.

[0009] The beneficial effects of this invention are as follows: By re-weaving basalt fiber cloth into a preform, constructing a boron nitride interface layer, and then placing it in a multiphase ceramic precursor slurry, the invention enables the interface layer, fibers, and multiphase ceramic matrix to synergistically construct a structure, thereby obtaining a ceramic matrix composite material with good thermal shock resistance and high-temperature load-bearing capacity, which meets the requirements for high-temperature structural components.

[0010] Furthermore, the basalt fiber preform in S1 has a multi-layer plain weave structure or a three-dimensional woven structure with a thickness of 2-5 mm and an interlayer fiber volume fraction of 45%-55%.

[0011] Furthermore, in S1, the basalt fiber cloth is cleaned and dried before weaving; after weaving, the basalt fiber preform is soaked in anhydrous ethanol and dried.

[0012] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The present invention uses continuous basalt fiber fabric as the reinforcing phase, and obtains the preform through desizing, reweaving and alcohol soaking processes. It utilizes the high strength, low density and good heat resistance of basalt fiber itself to overcome the disadvantages of carbon fiber being easy to oxidize in air, requiring complex anti-oxidation coatings and being costly in medium and high temperature environments.

[0013] Further cleaning involves immersion in acetone or anhydrous ethanol and ultrasonic cleaning for 20-40 minutes.

[0014] Preferably, the cleaning process involves ultrasonic cleaning by immersion in acetone or anhydrous ethanol for 30 minutes.

[0015] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention removes impurities and sizing agents from the surface of basalt fiber cloth by ultrasonic cleaning.

[0016] Furthermore, the drying conditions after cleaning are as follows: first, arrange the basalt fibers at 70-90℃, then raise the temperature to 100-140℃ at a heating rate of 0.5-1℃ / min, and finally raise the temperature to 150-200℃ at a heating rate of 0.5-2℃ / min, and keep warm for 2-4 hours.

[0017] Preferably, the drying conditions after cleaning are as follows: first, the basalt fibers are arranged at 80°C, then the temperature is increased to 120°C at a heating rate of 0.5°C / min, and finally the temperature is increased to 180°C at a heating rate of 1°C / min, and held at that temperature for 3 hours.

[0018] Furthermore, the soaking time in anhydrous ethanol is 10-15 minutes.

[0019] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention improves the wettability and pore openness of the fiber preform by soaking in anhydrous ethanol.

[0020] Furthermore, after soaking, the product is dried by natural air drying or drying at 50-70℃ for 20-40 minutes.

[0021] Preferably, the soaking and drying process involves natural air drying or drying at 60°C for 30 minutes.

[0022] Furthermore, the conditions for chemical vapor deposition in S2 are as follows: using ammonia borane as a precursor, the precursor heating temperature is 100-150℃; argon is used as the decomposition atmosphere, with a flow rate of 100-300 sccm; the deposition temperature is 700-900℃; the reaction pressure is 90-100 kPa; and the deposition time is 1-2 h.

[0023] Preferably, the precursor heating temperature is 130°C; the deposition temperature is 800°C.

[0024] Furthermore, the moving speed of the furnace tube heating zone in chemical vapor deposition is 0.5-1 cm / min.

[0025] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention ensures uniform deposition of decomposition products by controlling the moving speed of the furnace tube heating belt.

[0026] Furthermore, the thickness of the boron nitride interface layer deposited on the surface of S2 is 0.3-0.8 μm.

[0027] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The present invention constructs a boron nitride interface layer with a thickness of 0.3-0.8 μm on the surface of basalt fiber through a low-temperature chemical vapor deposition process. On the one hand, this interface layer effectively blocks the direct chemical reaction between the multiphase ceramic matrix and the basalt fiber in the high-temperature environment of sintering and service, avoiding fiber erosion, embrittlement or severe strength reduction. On the other hand, it utilizes the layered structure of BN to achieve a moderate interface bonding strength, causing cracks to deflect, bifurcate and pull out of the fiber at the interface, forming an obvious energy dissipation mechanism. Thus, while maintaining the strength of basalt fiber, it significantly improves the fracture toughness and flexural strength of the composite material.

[0028] Furthermore, before chemical vapor deposition in S2, the basalt fiber preform is kept at 500-700℃ and atmospheric pressure for 0.5-2 h.

[0029] Preferably, before chemical vapor deposition in S2, the basalt fiber preform is kept at 600°C and atmospheric pressure for 1 h.

[0030] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention performs deslurry pretreatment by means of heat treatment before chemical vapor deposition in order to remove organic matter and slurry residue on the surface.

[0031] Furthermore, the mass ratio of polycarbosilane to polyborazine in the precursor polymer of S3 is (3-5):1.

[0032] Preferably, the mass ratio of polycarbosilane to polyborazine in the precursor polymer of S3 is 4:1.

[0033] Furthermore, an appropriate amount of polysiloxane is added to the precursor polymer to improve film-forming properties.

[0034] Furthermore, the total mass of the precursor polymer in S3 is 50%-60% of the total mass of the powder material.

[0035] Furthermore, the powder material in S3 includes the following components in parts by mass: 30-50 parts SiC powder, 5-15 parts Si3N4 powder, 5-15 parts SiO2 powder, 5-10 parts Al2O3 powder, 5-10 parts ZrO2 powder, and 3-5 parts BN powder.

[0036] Preferably, the powder material in S3 comprises the following components in parts by mass: 40 parts SiC powder, 10 parts Si3N4 powder, 10 parts SiO2 powder, 8 parts Al2O3 powder, 8 parts ZrO2 powder, and 4 parts BN powder.

[0037] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The present invention constructs a multiphase ceramic matrix by combining multiphase ceramic powders such as SiC, Si3N4, SiO2, Al2O3 and ZrO2 with PCS / PBN ceramic precursors. The multiphase ceramic matrix provides a stable load-bearing skeleton at high temperature. The Si3N4 and ZrO2 phases improve the toughness of the matrix through crack deflection, phase transformation toughening and residual stress regulation, while the nano-ceramic phase generated by the cracking of PCS / PBN further fills the micro-defects.

[0038] Furthermore, the dispersion medium in S3 includes anhydrous ethanol or isopropanol.

[0039] Furthermore, the solid content of the ceramic precursor slurry in S3 is 55%-65%.

[0040] Furthermore, during the mixing of S3, 0.1%-1% by mass of dispersant is added for ball milling at a speed of 100-300 rpm for 12-18 h, with a ball-to-material ratio of (5-15):1.

[0041] Furthermore, the dispersant is polyvinylpyrrolidone, with a mass fraction of 0.5%.

[0042] Preferably, the ball mill rotates at 200 rpm and the ball-to-material ratio is 10:1.

[0043] Furthermore, the impregnation conditions in S4 are: vacuum impregnation at 0.005-0.02 MPa for 10-20 min.

[0044] Preferably, the impregnation conditions in S4 are: vacuum impregnation at 0.01 MPa for 15 min.

[0045] Furthermore, after vacuum impregnation, atmospheric pressure is slowly restored to allow the slurry to fully penetrate the fiber pores.

[0046] Furthermore, the drying conditions in S4 are as follows: first dry at 70-90℃ for 1-3 hours, and then dry at 100-150℃ for 0.5-2 hours.

[0047] Preferably, the drying conditions in S4 are: first drying at 80°C for 2 hours, and then drying at 120°C for 1 hour.

[0048] The beneficial effect of adopting the above-mentioned further technical solution is that it ensures that the solvent evaporates completely through specific drying conditions.

[0049] Furthermore, the impregnation and drying process is repeated 2-3 times in S4, with each time the mixture being cooled to room temperature.

[0050] The beneficial effects of adopting the above-mentioned further technical solution are: to obtain a higher volume fraction and density by repeated impregnation.

[0051] Furthermore, the sintering conditions in S5 are as follows: under a protective gas atmosphere, first heat to 550-650℃ at a heating rate of 1-5℃ / min, hold for 0.5-2 h, then heat to 750-850℃ at a heating rate of 1-3℃ / min; finally heat to 950-1050℃ at a heating rate of 1-2℃ / min, hold for 2-4 h.

[0052] Preferably, the sintering conditions in S5 are as follows: under a protective gas atmosphere, the temperature is first raised to 600°C at a heating rate of 3°C / min and held for 1 h, then raised to 800°C at a heating rate of 2°C / min; finally, the temperature is raised to 1000°C at a heating rate of 1°C / min and held for 3 h.

[0053] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention achieves preliminary densification through vacuum impregnation-heat sintering.

[0054] Furthermore, after sintering, the furnace is slowly cooled to room temperature, with a cooling rate not exceeding 5°C / min.

[0055] The beneficial effect of adopting the above-mentioned further technical solution is that cracking is avoided by controlling the cooling rate.

[0056] Furthermore, the conditions for chemical vapor infiltration in S6 are as follows: methyltrichlorosilane is used as the precursor, and hydrogen is used as the carrier gas; the reaction temperature is 1050-1150℃; the reaction pressure is 2-5 kPa; the reaction time is 20-40 h; the flow ratio of methyltrichlorosilane to hydrogen is 1:(5-15); and the flow rate of the reaction gas is 200-400 sccm.

[0057] Preferably, the flow rate ratio of methyltrichlorosilane to hydrogen is 1:10; and the reaction temperature is 1100℃.

[0058] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The present invention uses the CVI chemical vapor infiltration process of the MTS / H2 system to deposit SiC phase inside the pores of the pre-densified blank, so that the overall density of the material reaches more than 95% of the theoretical density and the porosity is less than 5%. At the same time, the dense SiC network formed by CVI significantly improves the oxidation resistance and high temperature strength of the matrix, so that the material of the present invention can still maintain high bending strength and dimensional stability under long-term service conditions of 800-1000℃, overcoming the problems of poor thermal shock performance and insufficient cycle stability of traditional single-phase ceramic matrices.

[0059] In a second aspect, the present invention provides a basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures, which is prepared by the above-described preparation method.

[0060] A third aspect of the present invention provides the application of the above-described basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures in the preparation of high-temperature structural components.

[0061] The present invention has the following beneficial effects: 1. This invention constructs a boron nitride interface layer on the surface of basalt fibers using a low-temperature chemical vapor deposition process. While maintaining the strength of the basalt fibers, it significantly improves the fracture toughness and flexural strength of the composite material. Compared with the system without the introduction of the boron nitride interface layer or with an uncontrolled interface layer thickness, the flexural strength retention rate at room temperature and 800-1000℃ is significantly improved, and the strength decay after thermal shock cycling is greatly reduced.

[0062] 2. This invention constructs a multiphase ceramic matrix by combining multiphase ceramic powders such as SiC, Si3N4, SiO2, Al2O3 and ZrO2 with PCS / PBN ceramic precursors. This enables the composite material to maintain high flexural strength and dimensional stability during long-term service at 800-1000℃, overcoming the problems of poor thermal shock resistance and insufficient cycle stability of traditional single-phase ceramic matrices.

[0063] 3. This invention uses continuous basalt fiber fabric as the reinforcing phase to prepare composite materials. It utilizes the high strength, low density and good heat resistance of basalt fiber itself to achieve stable load transfer in medium and high temperature environments. This avoids the disadvantages of carbon fiber reinforced ceramic matrix composites, such as the easy oxidation of carbon fibers in air, the need for complex anti-oxidation coatings and high costs. Compared with traditional resin-based basalt fiber composites, it significantly improves the mechanical properties and long-term thermal stability of the material in the 500-1000℃ range.

[0064] 4. The composite material prepared by this invention has high specific strength and high specific modulus, as well as excellent high temperature resistance, oxidation resistance and thermal shock resistance. It is particularly suitable for medium and high temperature complex working conditions such as combustion chamber liner, thermal protection components and high temperature structural support components, and has good engineering application value and promotion prospects. Attached Figure Description

[0065] Figure 1 This is a comparison chart of the porosity of the samples in the test examples; Figure 2 This is a comparison chart of the bending strength of the samples in the test examples; Figure 3 This is a comparison chart of sample densities in the experimental examples. Detailed Implementation

[0066] The principles and features of the present invention are described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, specific conditions or manufacturer-recommended conditions should be followed in the embodiments. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0067] The raw material parameters used in the examples are as follows: Basalt fiber cloth: 264 TEX 17 microns, tensile modulus 2000-3000 MPa; Silicon carbide (SiC) powder: average particle size 0.5-1μm, purity ≥99.9%; Silicon nitride (Si3N4) powder: average particle size 0.3-0.8μm, purity ≥99.9%; Silica (SiO2) powder: average particle size 0.1-0.3μm, purity ≥99.9%; Polycarbosilane (PCS): Liquid, viscosity 200-500 cP, ceramic yield approximately 70%; Polyboronazine (PBN): liquid precursor, ceramic yield 55%-70%, purity ≥98%; Zirconia (ZrO2) powder: average particle size 0.1-0.5 μm, purity ≥99%; Boron nitride (BN) powder: particle size 0.5-5 μm, purity ≥99%; Alumina (Al2O3) powder: average particle size 0.2-0.5 μm, purity ≥99.9%.

[0068] Example 1: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: S1, Re-knitting First, the basalt fiber cloth was ultrasonically cleaned in anhydrous ethanol for 30 min to remove surface impurities and sizing agent. Then, it was heated to 80℃ in an oven, then increased to 120℃ at a rate of 0.5℃ / min, and then increased to 180℃ at a rate of 1℃ / min, and held at this temperature for 3 h. Next, the dried fiber cloth was re-woven into a three-dimensional woven fiber preform with a thickness controlled at 4 mm and an interlayer fiber volume fraction of about 50%. Finally, the fiber preform was immersed in anhydrous ethanol for 10 min, then removed and dried in an oven at 60℃ for 30 min to obtain the basalt fiber preform.

[0069] Preparation of S2 and BN interface layers First, the basalt fiber preform obtained from S1 was placed in a quartz boat and kept at 600℃ under normal pressure for 1 h to remove surface organic matter and slurry residue. Then, low-temperature chemical vapor deposition (CVD) was performed under the following CVD conditions: ammonia borane (NH3BH3, purity 98.2%, Beijing Inno Chemical Technology Co., Ltd.) was used as the precursor, and the precursor heating temperature was 130℃; the decomposition atmosphere was high-purity argon (purity ≥99.999%), with a flow rate of 200 sccm; the deposition temperature was 800℃; the reaction pressure was 100 kPa; the deposition time was 1.5 h; and the furnace heating belt moving speed was 1 cm / min to ensure uniform product deposition. After deposition, the BN interface layer thickness was about 0.5 μm, resulting in a basalt fiber preform with a uniform BN layer on the surface.

[0070] S3, Preparation of ceramic-based slurry First, weigh the following powder materials according to the following weight proportions: 40 parts SiC powder, 10 parts Si3N4 powder, 10 parts SiO2 powder, 8 parts Al2O3 powder, 8 parts ZrO2 powder, and 4 parts BN powder. Then, take polycarbosilane and polyboronazine precursors and mix them at a mass ratio of 4:1. Add an appropriate amount of polysiloxane to improve film-forming properties, and control the total mass of the precursor to be 50% of the powder mass. Next, use anhydrous ethanol as the dispersion medium to mix the powder materials, precursor materials, and dispersion medium, and control the solid content of the slurry to be 60 wt%. Finally, add 0.5 wt% polyvinylpyrrolidone as a dispersant, place it in a planetary ball mill, and ball mill at 200 rpm for 15 hours with a ball-to-material ratio of 10:1 to form a uniform ceramic precursor slurry. Filter the slurry through a 100-mesh filter for later use.

[0071] S4, vacuum impregnation and drying densification The basalt fiber preform with a uniform BN layer on its surface obtained in S2 was completely immersed in the ceramic precursor slurry obtained in S3. The vacuum was drawn to 0.01 MPa and maintained for 15 min, and then slowly restored to normal pressure to allow the slurry to fully penetrate the fiber pores. The preform after impregnation was first dried in an oven at 80℃ for 2 h, and then kept in a vacuum drying oven at 120℃ for 1 h to ensure that the solvent was completely evaporated. The impregnation-drying process was repeated twice, with the temperature cooled to room temperature each time, to obtain the impregnated preform.

[0072] S5, Sintering and Pre-densification The impregnated preform obtained from S4 was placed in a high-temperature sintering furnace and sintered in a nitrogen atmosphere. The heating curve is shown below: first, the temperature was increased from room temperature to 600℃ at a heating rate of 3℃ / min and held for 1 h; then, the temperature was increased to 800℃ at a heating rate of 2℃ / min; finally, the temperature was increased to 1000℃ at a heating rate of 1℃ / min and held for 3 h to complete the inorganic conversion and preliminary sintering; after sintering, the temperature was slowly reduced to room temperature in the furnace, and the cooling rate was controlled not to exceed 5℃ / min to prevent cracking, thus obtaining a preliminary dense basalt fiber reinforced ceramic matrix composite preform.

[0073] S6, Chemical Vapor Infiltration (CVI) Densification A hot-wall CVI reactor was used to densify the blank obtained from S5 using methyltrichlorosilane (MTS) as a precursor and hydrogen as a carrier gas. The process conditions were as follows: reaction temperature was 1100℃, system pressure was 3 kPa, MTS / H2 flow ratio was 1:10, reaction time was 30 h, and reaction gas flow rate was 300 sccm. Basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures was obtained.

[0074] Example 2: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: The preparation method in this embodiment is the same as in embodiment 1, except that the proportion of powder materials in S3 is adjusted to 35 parts SiC powder, 10 parts Si3N4 powder, 12 parts SiO2 powder, 6 parts Al2O3 powder, 9 parts ZrO2 powder and 3 parts BN powder, while the other steps remain unchanged.

[0075] Comparative Example 1: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: The preparation method of this comparative example is the same as that of Example 1, except that the preparation of the BN interface layer in S2 is not performed, while the other steps remain unchanged.

[0076] Comparative Example 2: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: The preparation method of this comparative example is the same as that of Example 1, except that CVI densification in S6 is not performed, while the other steps remain unchanged.

[0077] Comparative Example 3: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: The preparation method of this comparative example is the same as that of Example 1, except that ZrO2 is not added to the powder material in S3, while the other steps remain unchanged.

[0078] Comparative Example 4: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: The preparation method of this comparative example is the same as that of Example 1, except that Si3N4 is not added to the powder material in S3, while the other steps remain unchanged.

[0079] Comparative Example 5: A method for preparing basalt fiber reinforced ceramic matrix composites suitable for high-temperature structures includes the following steps: The preparation method of this comparative example is the same as that of Example 1, except that polyboronazine is not added in S3, while the other steps remain unchanged.

[0080] Experimental example: The porosity, flexural strength, and density of the basalt fiber reinforced ceramic matrix composites prepared in Examples 1-2 and Comparative Examples 1-5 were measured under the following conditions: Porosity was measured in accordance with standard ISO 18754:2020 at a temperature of 20°C, humidity of 30%, and atmospheric pressure of 101 kPa. Bending strength was tested in accordance with standard GB / T 6569-2006 using an Instron 8801 electro-hydraulic servo fatigue testing system at room temperature of 20℃, humidity of 32%, and atmospheric pressure of 99 kPa. Density was measured in accordance with standard GB / T 1966-2024 at a temperature of 21℃, humidity of 32%, and atmospheric pressure of 101 kPa.

[0081] The experimental results are shown in Table 1 and Figure 1-3 As shown.

[0082] Table 1 Characterization Results

[0083] Porosity measurements showed that the porosities of both Examples 1 and 2 were at low levels, with little difference between them. This indicates that multiple vacuum impregnation-drying processes, heated sintering, and subsequent CVI chemical vapor infiltration processes can effectively fill the internal pores of the basalt fiber preform, significantly reducing the content of interconnected and closed pores within the material. The porosity of Example 1 was slightly lower than that of Example 2, mainly because the BN interface layer thickness and matrix composition were more optimized in Example 1. Combined with the nano-ceramic phase generated from the pyrolysis of the PCS / PBN precursor, this facilitated further filling of micropores, resulting in a higher degree of densification.

[0084] The porosity of Comparative Example 1 was significantly higher than that of Example Group 1. This is because no BN interface layer was deposited on the surface of the basalt fiber. The fiber and the ceramic matrix reacted directly during the sintering process, and microcracks and interface debonding were easily generated in the interface area, thereby forming a new pore structure and significantly increasing the overall porosity of the material.

[0085] Comparative Example 2 had the highest porosity. This is because without CVI densification treatment, relying solely on precursor pyrolysis and powder sintering is insufficient to completely eliminate residual pores inside the material. In particular, interconnected pore structures are easily formed inside the fiber bundles and in the interlayer region, leading to a significant increase in material porosity. This further illustrates that the CVI process plays a crucial role in reducing the porosity of ceramic matrix composites.

[0086] The porosity of Comparative Example 3 and Comparative Example 4 was higher than that of Example Group. Comparative Example 3 did not add ZrO2, and lacked the effect of liquid phase-assisted densification and phase transformation stress regulation at high temperature, which reduced the pore closure efficiency during sintering. Comparative Example 4 did not introduce Si3N4, which weakened the synergistic sintering effect of the multiphase ceramic skeleton, resulting in some pores remaining after sintering, thus increasing the porosity.

[0087] The porosity of Comparative Example 5 was also significantly higher than that of the Example Group. The main reason for this was that no PBN precursor was used. The BN and related nano-ceramic phases generated by the cracking of the precursor were missing, resulting in insufficient micropore filling capacity. At the same time, the uneven sintering shrinkage made it easy to form new microporous structures inside the matrix, ultimately leading to a significant increase in the porosity of the material.

[0088] Density measurements showed that the ceramic matrix composites of Examples 1 and 2 both had high densities, and the values ​​were similar. This indicates that a dense basalt fiber reinforced ceramic matrix composite with low porosity can be successfully prepared through multiphase ceramic powder-PCS / PBN precursor composite, vacuum impregnation-sintering, and subsequent CVI densification process. The density of Example 1 was slightly higher than that of Example 2, mainly because the proportions of SiC, BN, and the precursor in Example 1 were more conducive to forming a continuous and dense ceramic phase network, thereby increasing the overall bulk density.

[0089] The density of Comparative Example 1 was significantly lower than that of Example 1. This was because a BN interface layer was not constructed, and the interface bonding between the fiber and the ceramic matrix was uneven during the high-temperature sintering process. Microcracks and pores were easily formed in local areas, resulting in a decrease in the overall density of the material.

[0090] The density of Comparative Example 2 was further reduced because CVI chemical vapor infiltration densification was not performed, resulting in more residual pores inside the material, making it difficult to form a continuous and dense matrix structure, thus significantly reducing the bulk density of the composite material.

[0091] The densities of Comparative Examples 3 and 4 were both lower than those of Example 1. Comparative Example 3 did not introduce ZrO2, which weakened the phase transformation toughening and liquid-phase assisted densification effects. Comparative Example 4 did not add Si3N4, which weakened the synergistic sintering effect of the multiphase ceramic matrix and reduced the density of the material.

[0092] In Comparative Example 5, no PBN precursor was used. The nano-ceramic filling phase formed by precursor decomposition was missing, making it difficult to effectively fill the micropores, which ultimately led to a significant reduction in material density.

[0093] The flexural strength measurement results show that the flexural strength of both Example 1 and Example 2 is at a high level, and the difference between them is small. This indicates that by controlling the BN interface layer, designing the multiphase ceramic matrix, and using the CVI densification process, effective toughening can be achieved while ensuring the material's density. Among them, the flexural strength of Example 1 is slightly higher than that of Example 2, mainly because its interface structure and matrix composition are more conducive to the energy dissipation mechanisms such as crack deflection and fiber pull-out.

[0094] The flexural strength of Comparative Example 1 was significantly lower than that of Example Group 1 because it lacked a BN interface layer. The fiber-matrix interface was too strongly bonded, and cracks could easily penetrate the fiber directly, leading to brittle fracture of the material.

[0095] The bending strength of Comparative Example 2 is further reduced, mainly because the material has more internal pores, which easily leads to stress concentration under bending load, promoting rapid crack propagation.

[0096] Comparative Example 3, without the addition of ZrO2, lacked the effects of phase transformation toughening and residual stress regulation, resulting in a more direct crack propagation path and a significant decrease in flexural strength. Comparative Example 4, without the introduction of Si3N4, weakened the high-temperature strength and crack deflection ability of the matrix, which also led to a decrease in flexural performance.

[0097] Comparative Example 5, due to the lack of PBN precursor, lacks BN-related ceramic phases in the interface and matrix, resulting in insufficient fiber-matrix synergistic toughening effect. It is more prone to interface damage during sintering and loading, ultimately manifesting as a significant decrease in flexural strength.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures, characterized in that, Includes the following steps: S1. Weave basalt fiber cloth to obtain basalt fiber preform; S2. Using chemical vapor deposition, a boron nitride interface layer is deposited on the surface of the fiber preform obtained in S1 to obtain a basalt fiber preform coated with a boron nitride interface layer. S3. Mix the precursor polymer, powder material and dispersion medium to obtain ceramic precursor slurry; S4. The basalt fiber preform coated with boron nitride interface layer obtained in S2 is impregnated and dried in the ceramic precursor slurry obtained in S3 to obtain the impregnated preform. S5. The impregnated preform obtained in S4 is sintered to obtain a preliminary dense blank. S6. Chemical vapor infiltration is performed on the preliminary dense blank obtained in S5 to prepare a basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures. The precursor polymers in S3 include polycarbosilane, polyboronazine, and polysiloxane; the powder materials include SiC powder, Si3N4 powder, SiO2 powder, Al2O3 powder, ZrO2 powder, and BN powder.

2. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, The basalt fiber preform in S1 has a multi-layer plain weave structure or a three-dimensional woven structure with a thickness of 2-5 mm and an interlayer fiber volume fraction of 45%-55%.

3. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, In step S1, the basalt fiber cloth is cleaned and dried before weaving; after weaving, the basalt fiber preform is soaked in anhydrous ethanol and dried.

4. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, The chemical vapor deposition conditions in S2 are as follows: using ammonia borane as a precursor, the precursor heating temperature is 100-150℃; argon is used as the decomposition atmosphere, with a flow rate of 100-300 sccm; the deposition temperature is 700-900℃; the reaction pressure is 90-100 kPa; and the deposition time is 1-2 h. The thickness of the boron nitride interface layer deposited on the surface is 0.3-0.8 μm; Before chemical vapor deposition, the basalt fiber preform was kept at 500-700℃ and normal pressure for 0.5-2 h.

5. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, The mass ratio of polycarbosilane to polyborazine in the precursor polymer of S3 is (3-5):1; The total mass of the precursor polymer is 50%-60% of the total mass of the powder material; The powder material comprises the following components in parts by weight: 30-50 parts SiC powder, 5-15 parts Si3N4 powder, 5-15 parts SiO2 powder, 5-10 parts Al2O3 powder, 5-10 parts ZrO2 powder, and 3-5 parts BN powder. The dispersion medium includes anhydrous ethanol or isopropanol; The solid content of the ceramic precursor slurry is 55%-65%; Add 0.1%-1% of dispersant by mass during mixing and ball milling at a speed of 100-300 rpm for 12-18 h, with a ball-to-material ratio of (5-15):

1.

6. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, The impregnation conditions in S4 are: vacuum impregnation at 0.005-0.02 MPa for 10-20 min; The drying conditions are as follows: first dry at 70-90℃ for 1-3 hours, then dry at 100-150℃ for 0.5-2 hours; Repeat the soaking and drying process 2-3 times, cooling to room temperature between each cycle.

7. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, The sintering conditions in S5 are as follows: under a protective gas atmosphere, first heat to 550-650℃ at a heating rate of 1-5℃ / min, hold for 0.5-2 h, then heat to 750-850℃ at a heating rate of 1-3℃ / min; finally heat to 950-1050℃ at a heating rate of 1-2℃ / min, hold for 2-4 h.

8. The method for preparing basalt fiber reinforced ceramic matrix composite materials suitable for high-temperature structures according to claim 1, characterized in that, The conditions for chemical vapor infiltration in S6 are as follows: methyltrichlorosilane is used as the precursor and hydrogen is used as the carrier gas; the reaction temperature is 1050-1150℃; the reaction pressure is 2-5 kPa; the reaction time is 20-40 h; the flow ratio of methyltrichlorosilane to hydrogen is 1:(5-15); and the flow rate of the reaction gas is 200-400 sccm.

9. A basalt fiber reinforced ceramic matrix composite material suitable for high-temperature structures, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the basalt fiber reinforced ceramic matrix composite material of claim 9, suitable for high-temperature structures, in the preparation of high-temperature structural components.

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