A one-step method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials

Abstract

The present invention discloses a one-step method for preparing SiC nanowires and ultra-high temperature ceramics synergistically modified carbon-based composite materials. The present invention evenly lays a certain mass of catalyst-added silicide powder on the upper and lower sides of a low-density C / C, then places it in an SPS furnace, performs high-temperature heat treatment according to a set program, and then obtains the product after surface treatment. This method can prepare SiC nanowires and ultra-high temperature ceramics synergistically modified carbon-based composite materials in a one-step method, and uses low-melting-point phase silicide to promote infiltration while in-situ generating SiC nanowires / particles and carbide ultra-high temperature ceramic phases. Only one step is required to simultaneously introduce nano-reinforcements and antioxidant / ablative components, which can achieve simultaneous improvement in the mechanical and antioxidant / ablative properties of carbon-based composite materials. The preparation cycle of this method only takes 1 to 2 hours, effectively reducing the experimental cost and enabling high-throughput rapid screening of modified components.

Description

Technical Field

[0001] The present invention belongs to a technology for preparing a toughened carbon-based composite material, and relates to a method for preparing a carbon-based composite material synergistically modified by SiC nanowires and ultra-high temperature ceramics in one step. Background Art

[0002] C / C composite material is a carbon-based composite material reinforced with carbon fibers. It is prone to oxidation and ablation damage under high-temperature aerobic conditions, which hinders the further development of this composite material. Matrix modification is one of the most effective ways to solve this problem. By introducing ultra-high temperature ceramics into the interior of the carbon-based composite material, its ablation resistance can be improved.

[0003] Reference 1 “Shen YZ, Sun W, Xu YL, Wen QB, Zhang HB, Xiong X, Excellent oxyacetylene ablation performance of C / C-Me-Zr-Hf-C (Me=Ta, Si) composites prepared by a novel two-step molten salt infiltration, Journal of theEuropean Ceramic Society, 44 (2024) 3084-3098” used a two-step molten salt infiltration method to prepare C / C-Me-Zr-Hf (Me=Ta, Si) composites with excellent resistance to oxyacetylene ablation. The results show that the C / C-ZrHfC-SiC composites prepared by the two-step molten salt infiltration method have controllable ultra-high temperature ceramic structure and good ablation resistance.

[0004] Reference 2 “Dong ZJ, Yu HZ, Zhang Y, Liu B, Zhang H, Zhang JP, Fu QG, C / C-HfC-ZrC composites with excellent long-term ablation performance preparedby combining PIP and RMI, Ceramics International, 50 (2024) 13912-13923” prepared C / C-HfC-ZrC composites with excellent long-term ablation performance by combining polymer impregnation pyrolysis and reactive melt infiltration to resist long-term ablation. 2 After ablation in an oxyacetylene flame for 600s, the mass ablation rate and linear ablation rate were only 0.544mg / s and 0.107μm / s.

[0005] However, ultra-high temperature ceramics are very brittle, and introducing them into carbon-based composites may reduce their mechanical properties. Nanowires, due to their special geometric structure, have become a powerful tool for toughening composites. Therefore, some researchers have proposed methods such as polymer precursor conversion, chemical vapor deposition, and vapor-phase siliconization to introduce nanowires into carbon-based composites, effectively improving the mechanical properties of the composites.

[0006] CN111848196B reports a method for preparing silicon carbide ceramics toughened with in-situ silicon carbide nanowires. With the help of the toughening effect of the nanowires, the cracking tendency of the silicon carbide ceramics is reduced and its thermal shock resistance is improved. However, this method requires 3 to 6 impregnation-cracking processes to densify the composite material. The introduction of the nanowires is carried out separately from the densification process, resulting in a lengthy preparation cycle.

[0007] CN116396091B reports a method for preparing a high-strength, high-toughness, high-thermal-conductivity, and ablation-resistant ceramic gradient-modified C / C composite material. A C / C composite material with a gradient distribution of SiC nanowires and ceramic components was prepared. In this method, the ceramic components and SiC nanowires are introduced separately, and the preparation process is complicated. At the same time, the SiC nanowires introduced first may hinder the subsequent introduction of the ceramic components. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to solve the problems of high preparation cost, long cycle, complex process flow and the possibility that the nanowires introduced first may hinder the subsequent introduction of ceramics in the existing matrix modified carbon-based composite material strengthening and toughening methods.

[0009] To address the shortcomings of existing technologies, a one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultrahigh-temperature ceramics is provided. A catalyst (including, but not limited to, one or more of iron and nickel metals and their compounds) is mixed into a silicide powder. This catalyst is evenly spread over a low-density carbon / carbon layer and placed in a spark plasma sintering (SPS) mold. The mold is then placed in an SPS furnace, where a temperature and pressure program is established for high-temperature heat treatment. After polishing with a diamond grinding wheel, the SiC nanowire-reinforced carbide ultrahigh-temperature ceramic-SiC modified carbon-based composite material is obtained.

[0010] In order to achieve the above technical objectives, the technical solutions provided by the present invention are as follows:

[0011] A one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultra-high temperature ceramics comprises the following steps:

[0012] S1. Low density C / C pretreatment;

[0013] S2. Preparation of silicide powder;

[0014] S3. The silicide powder and the catalyst are ground and mixed uniformly;

[0015] S4 evenly spread the powder obtained from S3 on the upper and lower surfaces of the low-density C / C and placed in an SPS mold;

[0016] S5. Place the assembled mold in the SPS furnace, set the program for heat treatment, and remove it after cooling;

[0017] S6. The product surface is polished and cleaned to obtain a matrix-modified carbon-based composite material toughened by SiC nanowires.

[0018] As an improvement, the pre-processing method in step S1 is:

[0019] Use deionized water to ultrasonically clean the low-density C / C and dry it in a vacuum oven at 100-120°C for 10-15 hours. Ensure that the surface of the low-density C / C is dry.

[0020] As an improvement, the raw materials of the silicide powder in step S2 include: one or more of HfSi2, ZrSi2, TiSi2, TaSi2, and NbSi2 powders.

[0021] As an improvement, the preparation method of the silicide powder is:

[0022] The raw materials of the silicide powder are added into the ball mill according to proportion and subjected to ball milling treatment.

[0023] As an improvement, the ball milling method is:

[0024] The ball-to-material ratio is 2:1~4:1, the ball mill speed is 300~600r / min, the ball milling time is 7-12h, and then the silicide powder is placed in a vacuum oven at 100-120℃ and dried for 10~15h. The powder should be ensured to be dry.

[0025] As an improvement, the grinding method in step S3 is to grind the silicide powder and the catalyst in an agate mortar for 15 to 35 minutes.

[0026] As an improvement, the catalyst in step S3 includes but is not limited to one or more of iron and nickel metal elements and their compounds.

[0027] As an improvement, the mass ratio of the silicide powder to the catalyst in step S3 is 300:1 to 500:1.

[0028] As an improvement, the pressure program in step S5 is to apply a pressure of 6 to 8 kN throughout the entire process.

[0029] As an improvement, the temperature program in step S5 is:

[0030] Heat to 1500~1900℃ under vacuum environment, with a heating rate of 400~500℃ / min below 1500℃ and a heating rate of 100~200℃ / min above 1500℃, keep warm for 30~90min, and then cool to room temperature at a cooling rate of 100~200℃ / min.

[0031] As an improvement, the method of the polishing and cleaning step in step S6 is:

[0032] The graphite paper remaining on the sample surface was polished and cleaned using a 320-500 mesh diamond grinding wheel.

[0033] This invention proposes a one-step method for preparing SiC nanowire- and ultra-high-temperature ceramic-synergistically modified carbon-based composites. A predetermined mass of silicide powder containing a catalyst (including, but not limited to, one or more of iron and nickel metal elements and their compounds) is evenly laid above and below a low-density carbon / carbon composite and then placed in a SPS mold. The mold is then placed in an SPS furnace and subjected to high-temperature heat treatment using a temperature and pressure program. After polishing with a diamond grinding wheel, the SiC nanowire-reinforced matrix-modified carbon-based composite is obtained. Existing methods for preparing matrix-modified carbon-based composites with nanowires, such as polymer precursor conversion, chemical vapor deposition, and vapor siliconization, suffer from high production costs, long production cycles, and complex process flows. Furthermore, the initially introduced nanowires can easily clog pores, hindering the subsequent introduction of ceramics. This method, however, leverages the advantages of SPS equipment to significantly shorten the production cycle for integrated nanowire toughening and matrix modification. This method, with its simple steps and short production cycle, is suitable for the rapid and cost-effective preparation of SiC nanowire-reinforced carbon / ceramic matrix composites.

[0034] The advantages of the present invention are:

[0035] 1. This method can prepare SiC nanowire-toughened modified carbon-based composites in a one-step process. Silicides promote infiltration while simultaneously generating SiC nanowires / particles and carbide ultrahigh-temperature ceramics in situ. The simultaneous introduction of SiC nanowires, SiC particles, and carbide ceramic phases in a single step solves the problem of pore clogging caused by the initial introduction of nanowires / ceramic phases, which hinders the subsequent introduction of ceramic phases.

[0036] 2. This method simultaneously produces SiC nanowires and a multi-component ultrahigh-temperature ceramic phase through an in-situ reaction between silicide and pyrolytic carbon within a carbon-based composite. The in-situ synthesized nanowires can achieve multi-scale strengthening and toughening of the carbon-based composite and the ultrahigh-temperature ceramic phase, improving the mechanical properties of the composite. Furthermore, the introduction of the multi-component ultrahigh-temperature ceramic phase effectively enhances the composite's oxidation and ablation resistance.

[0037] 3. This method promotes the diffusion of silicide into the interior of low-density C / C by applying pressure. The preparation cycle only takes 1 to 2 hours, which can achieve high-throughput rapid screening of modified components. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the XRD spectrum of the SiC nanowire-toughened (Zr, Hf)C-SiC-C / C composite material in Example 1.

[0039] Figure 2 This is a cross-sectional SEM photograph of the SiC nanowire-toughened (Zr, Hf)C-SiC-C / C composite material in Example 1.

[0040] Figure 3 This is the XRD spectrum of the SiC nanowire-toughened (Zr, Hf)C-SiC-C / C composite material in Example 2.

[0041] Figure 4 This is a cross-sectional SEM photograph of the SiC nanowire-toughened (Zr, Hf)C-SiC-C / C composite material in Example 3. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Example 1

[0043] This embodiment discloses a one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultra-high temperature ceramics, comprising the following steps:

[0044] S1. Low-density C / C pretreatment

[0045] Ultrasonic cleaning of a Φ29 mm × 6 mm diaphragm with a density of 1.12 g / cm 3 The low-density C / C was placed in a vacuum oven at 100°C for 12 hours.

[0046] S2. Preparation of Silicide Powder

[0047] Pour ZrSi2 and HfSi2 in a molar ratio of 1:1 into a ball mill and use a ball mill for ball milling. Add an appropriate amount of penetration enhancer, the ball-to-material ratio is 2:1, the ball mill speed is 350r / min, and after ball milling for 7 hours, place the silicate powder in a vacuum oven at 120°C and dry it for 12 hours.

[0048] S3. Grind and mix the silicide powder and catalyst evenly

[0049] The silicate powder and nickel powder were ground in an agate mortar at a mass ratio of 360:1 for 20 min.

[0050] S4. Evenly spread 4.01 g of the mixed powder with nickel powder on the upper and lower surfaces of the low-density C / C and place it above the lower punch of the SPS mold. Wrap the low-density C / C and the powder with graphite paper. Place Φ30 mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press it into the upper punch.

[0051] S5. Place the assembled mold in an SPS furnace with a pressure of 7 kN. Heat to 1500°C at a heating rate of 450°C / min under vacuum. Continue heating to 1700°C at a heating rate of 200°C / min. Hold at this temperature for 30 minutes. Cool to room temperature at a cooling rate of 200°C / min and remove from the furnace.

[0052] S6. The graphite paper remaining on the sample surface was polished and cleaned using a 325-mesh diamond grinding wheel to obtain SiC nanowire-reinforced (Zr, Hf)C-SiC modified C / C composites.

[0053] Its XRD Figure 1 As shown in the figure, it can be seen that the sample only has carbon peaks, β-SiC and (Zr, Hf)C peaks, and no impurity phases. Its microstructure is as follows Figure 2 As shown, the sample has a high content of nanowires, the ceramic phase is tightly wrapped around the carbon fibers, and the nanowires are radially around the ceramic phase. Example 2

[0054] This embodiment discloses a one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultra-high temperature ceramics, comprising the following steps:

[0055] S1. Low-density C / C pretreatment

[0056] Ultrasonic cleaning of a Φ29 mm × 6 mm diaphragm with a density of 1.19 g / cm 3 The low-density C / C was placed in a vacuum oven at 100°C for 12 hours.

[0057] S2. Preparation of Silicide Powder

[0058] Pour ZrSi2 and HfSi2 into a ball mill at a molar ratio of 1:1 and use a ball mill for ball milling. The ball-to-material ratio is 2:1 and the ball milling speed is 400r / min. After ball milling for 8 hours, the silicide powder is placed in a vacuum oven at 120°C and dried for 12 hours.

[0059] S3. Grind and mix the silicide powder and catalyst evenly

[0060] The silicate powder and ferrous sulfate were ground in an agate mortar at a mass ratio of 500:1 for 30 min.

[0061] S4. Evenly spread 4.74 g of the mixed powder with ferrous sulfate on the upper and lower surfaces of the low-density C / C and place it above the lower punch of the SPS mold. Wrap the low-density C / C and powder with graphite paper. Place Φ30 mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press the upper punch in.

[0062] S5. Place the assembled mold in an SPS furnace with a pressure of 8 kN. Heat to 1500°C at a heating rate of 450°C / min under vacuum. Continue heating to 1700°C at a heating rate of 200°C / min. Hold at this temperature for 40 min. Cool to room temperature at a cooling rate of 200°C / min.

[0063] S6. The graphite paper remaining on the sample surface was polished and cleaned using a 320-mesh diamond grinding wheel to obtain a SiC nanowire-reinforced (Zr, Hf)C-SiC modified C / C composite.

[0064] The XRD of the product in this embodiment is as follows Figure 3 As shown in the figure, the sample only has carbon peaks, β-SiC and (Zr, Hf)C peaks, and no impurity phases. Example 3

[0065] This embodiment discloses a one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultra-high temperature ceramics, comprising the following steps:

[0066] S1. Low-density C / C pretreatment

[0067] Ultrasonic cleaning of a Φ29 mm × 6 mm diaphragm with a density of 1.24 g / cm 3 The low-density C / C was placed in a vacuum oven at 100°C for 12 hours.

[0068] S2. Preparation of Silicide Powder

[0069] Pour ZrSi2 and HfSi2 into a ball mill at a molar ratio of 2:1 and use a ball mill for ball milling. The ball-to-material ratio is 2:1 and the ball milling speed is 300r / min. After ball milling for 8 hours, the silicide powder is placed in a vacuum oven at 120°C and dried for 12 hours.

[0070] S3. Grind and mix the silicide powder and catalyst evenly

[0071] Silicide powder and nickel powder were ground in an agate mortar at a mass ratio of 400:1 for 25 min.

[0072] S4. Evenly spread 2.37 g of the mixed powder with nickel powder on the upper and lower surfaces of the low-density C / C and place it above the lower punch of the SPS mold. Wrap the low-density C / C and the powder with graphite paper. Place Φ30 mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press it into the upper punch.

[0073] S5. Place the assembled mold in an SPS furnace with a pressure of 7.5 kN. Heat to 1500°C at a heating rate of 450°C / min under vacuum. Continue heating to 1750°C at a heating rate of 200°C / min. Hold at this temperature for 30 minutes. Cool to room temperature at a cooling rate of 200°C / min.

[0074] S6. The graphite paper remaining on the sample surface was polished and cleaned using a 320-mesh diamond grinding wheel to obtain a SiC nanowire-reinforced (Zr, Hf)C-SiC modified C / C composite.

[0075] The microstructure of the product in this embodiment is as follows Figure 4 As shown, the ceramic phase is tightly wrapped around the carbon fibers, and the nanowires grow between the ceramic phases. Example 4

[0076] This embodiment discloses a one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultra-high temperature ceramics, comprising the following steps:

[0077] S1. Low-density C / C pretreatment

[0078] Ultrasonic cleaning of a Φ29 mm × 6 mm diaphragm with a density of 1.24 g / cm 3 The low-density C / C was placed in a vacuum oven at 110°C and dried for 10 hours.

[0079] S2. Preparation of Silicide Powder

[0080] TiSi2 and TaSi2 were poured into a ball mill at a molar ratio of 2:1 and ball milled using a ball mill with a ball-to-material ratio of 4:1 and a ball mill speed of 600 r / min. After ball milling for 10 hours, the silicide powder was placed in a vacuum oven at 120°C and dried for 12 hours.

[0081] S3. Grind and mix the silicide powder and catalyst evenly

[0082] Silicide powder and nickel powder were ground in an agate mortar at a mass ratio of 300:1 for 15 min.

[0083] S4. Evenly spread 2.37 g of the mixed powder with nickel powder on the upper and lower surfaces of the low-density C / C and place it above the lower punch of the SPS mold. Wrap the low-density C / C and the powder with graphite paper. Place Φ30 mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press it into the upper punch.

[0084] S5. Place the assembled mold in an SPS furnace with a pressure set to 6 kN. Heat to 1500°C at a heating rate of 400°C / min under vacuum. Continue heating to 1800°C at a heating rate of 100°C / min. Hold at this temperature for 30 minutes. Cool to room temperature at a cooling rate of 100°C / min and remove from the furnace.

[0085] S6. The graphite paper remaining on the sample surface was polished and cleaned using a 400-mesh diamond grinding wheel to obtain a SiC nanowire-reinforced (Ti, Ta)C-SiC modified C / C composite. Example 5

[0086] This embodiment discloses a one-step method for preparing a carbon-based composite material synergistically modified with SiC nanowires and ultra-high temperature ceramics, comprising the following steps:

[0087] S1. Low-density C / C pretreatment

[0088] Ultrasonic cleaning of a Φ29 mm × 6 mm diaphragm with a density of 1.24 g / cm 3 The low-density C / C was placed in a vacuum oven at 120°C and dried for 10 hours.

[0089] S2. Preparation of Silicide Powder

[0090] TiSi2 and NbSi2 were poured into a ball mill at a molar ratio of 2:1 and ball milled using a ball mill. The ball-to-material ratio was 2:1 and the ball mill speed was 500 r / min. After ball milling for 12 hours, the silicide powder was placed in a vacuum oven at 120°C and dried for 15 hours.

[0091] S3. Grind and mix the silicide powder and catalyst evenly

[0092] Silicide powder and nickel powder were ground in an agate mortar at a mass ratio of 500:1 for 35 min.

[0093] S4. Evenly spread 2.37 g of the mixed powder with nickel powder on the upper and lower surfaces of the low-density C / C and place it above the lower punch of the SPS mold. Wrap the low-density C / C and the powder with graphite paper. Place Φ30 mm graphite paper in the area where the powder contacts the upper and lower punches, and finally press it into the upper punch.

[0094] S5. Place the assembled mold in an SPS furnace with a pressure of 8 kN. Heat to 1500°C at a heating rate of 500°C / min under vacuum. Continue heating to 1900°C at a heating rate of 100°C / min. Hold at this temperature for 30 min. Cool to room temperature at a cooling rate of 150°C / min.

[0095] S6. The graphite paper remaining on the sample surface was polished and cleaned using a 500-mesh diamond grinding wheel to obtain SiC nanowire-reinforced (Ti, Nb)C-SiC modified C / C composites.

[0096] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A one-step method for preparing SiC nanowires and ultra-high temperature ceramics synergistically modified carbon-based composite materials, characterized in that: The steps include: S1. Low density C / C pretreatment; S2. Preparation of silicide powder; S3. The silicide powder and the catalyst are ground and mixed evenly; S4 evenly spread the powder obtained from S3 on the upper and lower surfaces of the low-density C / C and placed in an SPS mold; S5. Place the assembled mold in the SPS furnace, set the temperature and pressure program for heat treatment, and remove it after cooling; S6. Polish and clean the product surface to obtain a SiC nanowire-toughened matrix-modified carbon-based composite material; The silicide simultaneously generates SiC nanowires / particles and carbide ultra-high temperature ceramics in situ.

2. The method for preparing SiC nanowire and ultra-high temperature ceramic modified carbon-based composite materials in one step according to claim 1, characterized in that: The pretreatment method in step S1 is: The low-density C / C was ultrasonically cleaned with deionized water and dried in a vacuum oven at 100-120 °C for 10-15 h to ensure that the surface of the low-density C / C was dry.

3. The method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials in one step according to claim 1, characterized in that: The raw materials of the silicide powder in step S2 include: one or more of HfSi2, ZrSi2, TiSi2, TaSi2, and NbSi2 powders.

4. The method for preparing SiC nanowire and ultra-high temperature ceramic modified carbon-based composite materials in one step according to claim 3, characterized in that: The preparation method of the silicide powder is as follows: The raw materials of the silicide powder are added into the ball mill according to proportion and subjected to ball milling treatment.

5. The method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials in one step according to claim 4, characterized in that: The method of the ball milling treatment is: The ball-to-material ratio is 2:1~4:1, the ball mill speed is 300~600r / min, the ball milling time is 7-12h, and then the silicide powder is placed in a vacuum oven at 100-120℃ and dried for 10~15h to ensure that the powder is dry.

6. The method for preparing SiC nanowire and ultra-high temperature ceramic modified carbon-based composite materials in one step according to claim 1, characterized in that: The grinding method in step S3 is: Grind the silicide powder and catalyst in an agate mortar for 15-35 minutes; The mass ratio of the silicide powder to the catalyst in step S3 is 300:1 to 500:

1.

7. The method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials in one step according to claim 1, characterized in that: The catalyst in step S3 includes one or more of iron and nickel metal elements and their compounds.

8. The method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials in one step according to claim 1, characterized in that: The pressure program in step S5 is to apply a pressure of 6 to 8 kN throughout the entire process.

9. The method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials in one step according to claim 1, characterized in that: The temperature program in step S5 is: Heat to 1500~1900℃ under vacuum environment, with a heating rate of 400~500℃ / min below 1500℃ and a heating rate of 100~200℃ / min above 1500℃, keep warm for 30~90min, and then cool to room temperature at a cooling rate of 100~200℃ / min.

10. The method for preparing SiC nanowire and ultra-high temperature ceramic synergistically modified carbon-based composite materials in one step according to claim 1, characterized in that: The method of the polishing and cleaning step in step S6 is: The graphite paper remaining on the sample surface was polished and cleaned using a 320-500 mesh diamond grinding wheel.

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