Device for preparing carbon / carbon composite material thin plate and method for preparing the thin plate

Abstract

The present invention discloses a device for preparing a carbon / carbon composite material sheet and a method for preparing the sheet. The device includes a high-silica fiber microporous air guide plate, and the device also includes a hollow graphite plate. The hollow graphite plate and the high-silica fiber microporous air guide plate are stacked to form a support plate. A carbon / carbon composite material sheet blank is sandwiched between the high-silica fiber microporous air guide plates of the two support plates. The two support plates are fastened with fasteners to form a device for preparing a carbon / carbon composite material sheet. The device for preparing a carbon / carbon composite material sheet of the present invention can uniformly guide the carbon source gas to the carbon / carbon composite material sheet, solve the problem of uniform chemical vapor carburization and deformation control of the sheet, and prepare a carbon / carbon composite material sheet with uniform density and smooth surface, the density of which is 1.5-1.9g / cm 3 , thickness is 2.0‑8.0mm.

Description

Technical Field

[0001] The invention discloses a device for preparing a carbon / carbon composite material thin plate and a method for preparing the thin plate, belonging to the technical field of chemical vapor deposition. Background Art

[0002] Carbon / carbon composite sheet refers to a flat, flat component with a thickness between 2.0 and 8.0 mm and a smooth surface. High-performance carbon / carbon composite sheet is typically produced using chemical vapor carburizing. However, because chemical vapor carburizing is a high-temperature chemical treatment, ultra-thin flat components are susceptible to deformation during this process, requiring the use of standardized tooling to control deformation.

[0003] The existing technology uses a hollow graphite tool to clamp ultra-thin carbon / carbon composite materials for chemical vapor deposition. The carbon source gas is guided to the component through the hollow holes to implement chemical vapor carburization. The high-temperature strength of graphite is utilized to achieve deformation control of the component at high temperatures and prepare carbon / carbon composite material sheets. However, due to certain requirements for the high-temperature strength of graphite, in order to maintain the clamping strength of the hollow graphite tool, the gaps between the hollow holes are large, and usually the area of ​​the hollow part does not exceed 60%. When the hollow holes of this hollow graphite tool are used to guide the gas for chemical vapor deposition, the carbon source gas will be unevenly distributed on the surface of the component. The hollowed parts will obtain effective carburization, while the non-hollowed parts will not be effectively carburized, which will seriously affect the uniformity of the density and performance of the component. As a result, the maximum average density of the carbon / carbon composite material sheet prepared by the existing technology of the hollow graphite tool can only reach 1.7g / cm 3 , which cannot meet the density requirements of carbon / carbon composite thin panels. In patent (201811277724.5), the inventor used carbon fiber to prepare a microporous air guide plate to solve the problem of uniform densification of ultra-thin panels with a thickness of less than 1 mm. However, the carbon fiber microporous air guide plate has high manufacturing costs and limited air guide depth. Therefore, it is only suitable as an air guide tool for panels with a thickness of less than 1 mm, limiting its application to thin panels with a thickness of 2 mm to 8 mm.

[0004] Therefore, it is urgently needed in the art to invent a device for preparing a carbon / carbon composite material sheet with uniform density and a method for preparing the carbon / carbon composite material sheet. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing an apparatus and method for preparing carbon / carbon composite thin sheets. The apparatus of the present invention has a rational structure, provides a uniform transmission path for carbon source gas, and has strong gas conduction capabilities, ensuring uniform deposition of the carbon source gas on carbon / carbon composite thin sheets with a thickness of 2 mm to 8 mm. The method of the present invention can produce carbon / carbon composite thin sheets with uniform density and satisfactory deformation.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention discloses a device for preparing a carbon / carbon composite material thin plate. The device comprises a high-silica fiber microporous air guide plate. The high-silica fiber microporous air guide plate is a high-silica fiber / carbon composite plate.

[0008] The inventors unexpectedly discovered that using high-silica fiber / carbon composite plates as microporous air guide plates has more excellent air conduction capabilities, enabling carbon source gas to be evenly deposited on carbon / carbon composite material sheets with a thickness of 2mm-8mm. At the same time, the price of high-silica fiber is much lower than that of carbon fiber, thereby significantly reducing tooling costs, making it suitable for large-scale industrial production.

[0009] In a preferred embodiment, the thickness of the high silica fiber microporous air guide plate is 3-12 mm, and the density is 0.2-1.5 g / cm 3 .

[0010] In a preferred embodiment, the diameter of the high-silica fiber in the high-silica fiber microporous air guide plate is 6-10 μm, and the silicon oxide content thereof is 96-98%.

[0011] The inventors have found that when high-silica fibers with the above diameter are used in the high-silica fiber microporous air guide plate, the final air guide performance is optimal.

[0012] According to a preferred embodiment, the preparation process of the high-silica fiber microporous air guide plate is as follows: the high-silica fiber web is needle-punched into a flat felt, and then subjected to chemical vapor carburization for densification and hardening; and then machined to obtain the high-silica fiber microporous air guide plate.

[0013] Further preferably, the thickness of the flat felt is 5-15 mm and the density is 0.09-0.12 g / cm 3 .

[0014] The inventors found that the main component of high silica fiber is silicon dioxide, which has a higher density than carbon fiber. However, due to its high hardness, it can form a 0.09-0.12g / cm 3 The low-density flat felt has more micron-scale pores after densification and hardening, and has a gas-conducting capacity that is much better than that of the carbon fiber microporous gas guide plate.

[0015] Although carbon fiber has a lower density, its hardness is lower, and it cannot be effectively formed to obtain 0.09-0.12g / cm 3 of carbon fiber felt.

[0016] Further preferably, the process of chemical vapor carburizing densification and hardening is: using C3H6 as carbon source gas, controlling the furnace temperature to 920-960°C and the furnace pressure to 1-12kPa, and accumulating chemical vapor carburizing for 10-300h before taking out of the furnace.

[0017] After the above densification process, the flat felt is chemically vapor carburized to a density of 0.2-1.5g / cm 3 ; Then machine it to 3-12mm.

[0018] In a preferred embodiment, the device further includes a hollow graphite plate, and the hollow graphite plate and the high-silica fiber microporous air guide plate are stacked to form a support plate. A carbon / carbon composite material sheet blank is sandwiched between the high-silica fiber microporous air guide plates of the two support plates, and the two support plates are fastened with fasteners to form a device for preparing carbon / carbon composite material sheets.

[0019] Further preferably, the thickness of the hollow graphite plate is 15-30 mm, and the hollow area accounts for 30-50% of the total area of ​​the graphite plate.

[0020] Further preferably, fastening the two support plates with fasteners is performed by arranging fasteners on the hollow graphite plate; the fasteners are bolts and nuts, the bolts pass through bolt holes provided on the hollow graphite plate, and are fastened with nuts.

[0021] The present invention provides a device for preparing carbon / carbon composite material thin plates. The structural assembly order is: hollow graphite plate + high-silica fiber microporous air guide plate + carbon / carbon composite material thin plate blank + high-silica fiber microporous air guide plate + hollow graphite plate, and the carbon / carbon composite material thin plate blank is sandwiched between two high-silica fiber microporous air guide plates.

[0022] The present invention provides a method for preparing a carbon / carbon composite material thin plate, which comprises placing a device for the carbon / carbon composite material thin plate in a chemical vapor deposition furnace for chemical vapor carburizing and densification; the chemical vapor carburizing and densification process parameters are: using C3H6 as a carbon source gas, controlling the furnace temperature to 920-960°C, the furnace pressure to 1-12kPa, and taking the plate out of the furnace after a cumulative chemical vapor carburizing of 100-400 hours.

[0023] In the present invention, C3H6 is used as the carbon source gas to densify the carbon / carbon composite material sheet. With C3H6 as the carbon source gas, the carburizing furnace temperature is 920-960°C, which is lower than that of CH4 as the gas source, which will effectively reduce energy consumption. At the same time, the molecular weight of C3H6 is larger than that of CH4, and the C content of a single molecule is 4 times that of CH4, so its densification efficiency is relatively high. However, the C3H6 molecule is large, and the gas conduction capacity of the microporous gas guide plate is required to be higher. Therefore, it is necessary to use the 0.09-0.12g / cm 3Low-density high-silica fiber flat felt is used to prepare high-silica fiber composite gas guide plates with lower density and better gas conduction ability, thereby effectively and evenly guiding the carbon source gas to the carbon / carbon composite sheet, and efficiently densifying the carbon / carbon composite sheet.

[0024] The present invention provides a method for preparing a carbon / carbon composite material sheet, wherein the thickness of the carbon / carbon composite material sheet is 2.0-8.0 mm, and the density of the carbon fiber is 0.2-0.9 g / cm 3 The density of the carbon / carbon composite sheet obtained after chemical vapor carburization densification is 1.5-1.9g / cm 3 .

[0025] The initial high silica fiber density in the high silica fiber microporous air guide plate is less than the initial carbon fiber density in the carbon / carbon composite material sheet.

[0026] Advantages and positive effects

[0027] The present invention needle-punches a high-silica fiber mesh into a flat felt, densifies and hardens it through chemical vapor carburization, and then processes it into a high-silica fiber microporous air guide plate. The high-silica fiber microporous air guide plate is used to uniformly guide the carbon source gas to the carbon / carbon composite sheet, solving the problem of uniform chemical vapor carburization and deformation control of the sheet. With an initial carbon fiber density of 0.2-0.9g / cm 3 The carbon / carbon composite material sheet blank can be prepared by using the device for preparing the carbon / carbon composite material sheet of the present invention to obtain a carbon / carbon composite material sheet with a density of 1.5-1.9g / cm 3 The device for preparing carbon / carbon composite sheet of the present invention utilizes a high-silica fiber microporous gas guide plate to uniformly guide the carbon source gas to the carbon / carbon composite sheet, thereby solving the problem of uniform chemical vapor carburization and deformation control of the sheet, and can prepare a carbon / carbon composite sheet with uniform density and smooth surface, with a density of 1.5-1.9g / cm 3 , thickness is 2.0-8.0mm.

[0028] The present invention utilizes a high-silica fiber microporous gas guide plate to uniformly guide the carbon source gas to the carbon / carbon composite material thin plate, thereby solving the problem of uniform chemical vapor carburization and deformation control of the thin plate, and has the following advantages.

[0029] 1. The thickness of the high-silica fiber microporous air guide plate of the present invention is controlled at 3-12 mm, and there are a large number of micron-scale pores inside. An effective channel for carbon source gas is constructed between the hollow graphite plate and the carbon / carbon composite material sheet, and the carbon source gas is evenly guided to the carbon / carbon composite material sheet to achieve uniform chemical vapor carburization.

[0030] 2. The high-silica fiber microporous air guide plate of the present invention has an initial high-silica fiber density that is lower than the initial carbon fiber density of the thin plate, that is, the specific surface area of ​​the carbon fibers in the thin plate is larger, the adsorption of the carbon source gas is stronger, and the carburizing efficiency is higher. During the carburizing process, the thin plate obtains a density higher than that of the microporous air guide plate.

[0031] 3. The high-silica fiber microporous air guide plate of the present invention is a high-silica fiber reinforced composite material with good high-temperature strength. It has a solidifying effect on the carbon / carbon composite material sheet, avoiding the phenomenon of easy deformation and dimensional instability of the sheet material.

[0032] 4. The device for preparing carbon / carbon composite material sheets of the present invention has an initial carbon fiber density of 0.2-0.9 g / cm 3 The thin plate is used as raw material, and the density of 1.5-1.9g / cm 3 , carbon / carbon composite material sheet with a thickness of 2.0-8.0mm.

[0033] 5. The high-silica fiber microporous air guide plate of the present invention is prepared by chemical vapor carburizing method and uses high-silica fiber as raw material. Compared with using carbon fiber as raw material, the fiber raw material cost is reduced by 90%.

[0034] 6. The high-silica fiber microporous air guide plate of the present invention is prepared by a chemical vapor carburizing method, using C3H6 as the carbon source gas and a carburizing furnace temperature of 920-960°C. Compared with the carburizing furnace temperature of 1000-1200°C for preparing carbon fiber microporous air guide plates, it is reduced by 80-240°C, effectively saving electricity energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Attachment Figure 1 This is a process flow chart for preparing the high-silica fiber microporous air guide plate of the present invention;

[0036] Attachment Figure 2 An assembly diagram of an apparatus for preparing a carbon / carbon composite material sheet according to the present invention;

[0037] from Figure 1 In the figure, it can be seen that the best process flow of the present invention;

[0038] from Figure 2 In the figure, it can be seen that the best tooling assembly method of the present invention is provided. DETAILED DESCRIPTION

[0039] See attached Figure 2A device for preparing a carbon / carbon composite material sheet, the device comprising a hollow graphite plate and a high-silica fiber microporous air guide plate; the hollow graphite plate and the high-silica fiber microporous air guide plate are stacked to form a support plate, an ultra-thin carbon / carbon composite material blank is sandwiched between the high-silica fiber microporous air guide plates of the two support plates, and the two support plates are fastened with fasteners to form the device for preparing a carbon / carbon composite material sheet;

[0040] The thickness of the high silica fiber microporous air guide plate is 3-12 mm, and the density is 0.2-1.5 g / cm 3 ;

[0041] The thickness of the hollow graphite plate is 15-30 mm, and the hollow area accounts for 30-50% of the total area of ​​the graphite plate. Bolts are passed through bolt holes arranged on the hollow graphite plate and fastened with nuts.

[0042] The high-silica fiber in the high-silica fiber web used in the following examples has a diameter of 6-10 μm and a silicon oxide content of 96-98%.

[0043] Example 1:

[0044] See attached Figure 1 In a device for preparing a carbon / carbon composite material sheet, a high-silica fiber microporous air guide plate is prepared using the following scheme:

[0045] The thickness is 1mm and the density is 0.02g / cm 3 The high silica fiber mesh is needle-punched into a thickness of 5mm and a density of 0.1g / cm 3 The flat felt was chemically vapor carburized to increase the density to 1.5g / cm 3 After hardening, machining is performed to obtain a 3mm thick high silica fiber microporous air guide plate;

[0046] The process parameters of chemical vapor carburizing and densification are as follows: using C3H6 as carbon source gas, controlling the furnace temperature at 950℃ and the furnace pressure at 3kPa, and taking the product out of the furnace after accumulating chemical vapor carburizing for 200h.

[0047] The apparatus for preparing carbon / carbon composite sheet was placed in a chemical vapor deposition furnace for chemical vapor carburization densification of the carbon / carbon composite sheet. The chemical vapor carburization densification process parameters were: using C3H6 as the carbon source gas, controlling the furnace temperature at 950°C, the furnace pressure at 2kPa, and accumulating chemical vapor carburization for 350 hours before exiting the furnace.

[0048] The assembly order of the device structure for preparing carbon / carbon composite sheet is: hollow graphite plate + high silica fiber microporous air guide plate + carbon / carbon composite sheet + high silica fiber microporous air guide plate + hollow graphite plate, with the carbon / carbon composite sheet sandwiched between the two high silica fiber microporous air guide plates.

[0049] The thickness of the carbon / carbon composite sheet is 3 mm and the carbon fiber density is 0.8 g / cm 3 The density of the carbon / carbon composite sheet obtained after chemical vapor carburization densification is 1.9g / cm 3 .

[0050] Example 2:

[0051] See attached Figure 1 In a device for preparing a carbon / carbon composite material sheet, a high-silica fiber microporous air guide plate is prepared using the following scheme:

[0052] The thickness is 1mm and the density is 0.02g / cm 3 The high silica fiber mesh is needle-punched into a thickness of 10mm and a density of 0.12g / cm 3 The flat felt was chemically vapor carburized to increase the density to 0.9g / cm 3 After hardening, machining is performed to obtain a 7mm thick high silica fiber microporous air guide plate;

[0053] The process parameters of chemical vapor carburizing and densification are as follows: using C3H6 as carbon source gas, controlling the furnace temperature at 930℃ and the furnace pressure at 6kPa, and taking the product out of the furnace after accumulating chemical vapor carburizing for 80h.

[0054] The apparatus for preparing carbon / carbon composite sheet was placed in a chemical vapor deposition furnace for chemical vapor carburization densification of the carbon / carbon composite sheet. The chemical vapor carburization densification process parameters were: using C3H6 as the carbon source gas, controlling the furnace temperature at 930°C, the furnace pressure at 6 kPa, and accumulating chemical vapor carburization for 160 hours before exiting the furnace.

[0055] The assembly order of the device structure for preparing carbon / carbon composite sheet is: hollow graphite plate + high silica fiber microporous air guide plate + carbon / carbon composite sheet + high silica fiber microporous air guide plate + hollow graphite plate, with the carbon / carbon composite sheet sandwiched between the two high silica fiber microporous air guide plates.

[0056] The thickness of the carbon / carbon composite sheet is 7 mm and the carbon fiber density is 0.5 g / cm 3 The density of the carbon / carbon composite sheet obtained after chemical vapor carburization densification is 1.65g / cm 3 .

[0057] Example 3:

[0058] See attached Figure 1 In a device for preparing a carbon / carbon composite material sheet, a high-silica fiber microporous air guide plate is prepared using the following scheme:

[0059] The thickness is 1mm and the density is 0.02g / cm 3The high silica fiber mesh is needle-punched into a thickness of 14mm and a density of 0.11g / cm 3 The flat felt is chemically vapor carburized to increase the density to 0.5g / cm 3 After hardening, machining is performed to obtain a 11 mm thick high silica fiber microporous air guide plate;

[0060] The process parameters of chemical vapor carburizing and densification are as follows: using C3H6 as carbon source gas, controlling the furnace temperature at 920℃ and the furnace pressure at 6kPa, and taking the product out of the furnace after accumulating chemical vapor carburizing for 60 hours.

[0061] The apparatus for preparing carbon / carbon composite sheet was placed in a chemical vapor deposition furnace for chemical vapor carburization densification of the carbon / carbon composite sheet. The chemical vapor carburization densification process parameters were: using C3H6 as the carbon source gas, controlling the furnace temperature at 920°C and the furnace pressure at 10 kPa, and accumulating chemical vapor carburization for 210 hours before exiting the furnace.

[0062] The assembly order of the device structure for preparing carbon / carbon composite sheet is: hollow graphite plate + high silica fiber microporous air guide plate + carbon / carbon composite sheet + high silica fiber microporous air guide plate + hollow graphite plate, with the carbon / carbon composite sheet sandwiched between the two microporous air guide plates;

[0063] The thickness of the carbon / carbon composite sheet is 5 mm and the carbon fiber density is 0.3 g / cm 3 The density of the carbon / carbon composite sheet obtained after chemical vapor carburization densification is 1.86g / cm 3 .

[0064] Comparative Example 1:

[0065] When the thickness of the prepared high silica fiber microporous air guide plate is 14 mm and the density is 1.6 g / cm 3 When the carbon source gas is heated to 100 ℃, the micropores in the gas guide plate are reduced in size and partially become closed pores, which cannot form an effective carbon source gas channel and cannot guide the carbon source gas to the carbon / carbon composite material sheet for chemical vapor densification.

[0066] Comparative Example 2:

[0067] When the thickness of the prepared microporous air guide plate is 1 mm and the density is 0.1 g / cm 3 When the gas guide plate is thin, its strength is insufficient to shape the carbon / carbon composite material sheet; in addition, the micropores in the gas guide plate are large in size and cannot effectively divert the carbon source gas, and cannot achieve uniform chemical vapor carburizing of the carbon / carbon composite material sheet.

[0068] Comparative Example 3

[0069] Other conditions are the same as those in Example 1, except that the high silica fiber microporous air guide plate is replaced by the microporous air guide plate prepared in Example 1 according to patent (201811277724.5). As a result, the density of the obtained carbon fiber flat felt is 0.2 g / cm 3 The carbon fiber microporous air guide plate has a low air conduction capacity. The density of the carbon / carbon composite material sheet prepared by the carbon fiber microporous air guide plate is 1.7g / cm 3 , which is much lower than the 1.9g / cm2 of the high silica fiber microporous air guide plate. 3 .

Claims

1. A method for preparing a carbon / carbon composite material sheet, characterized in that: The device of carbon / carbon composite material thin plate is placed in a chemical vapor deposition furnace for chemical vapor carburizing and densification. The chemical vapor carburizing and densification process parameters are: using C3H6 as carbon source gas, controlling the furnace temperature to 920-960℃, the furnace pressure to 1-12kPa, and accumulating chemical vapor carburizing for 100-400 hours before taking out of the furnace; The thickness of the carbon / carbon composite material sheet is 2.0-8.0 mm, and the density of the carbon fiber is 0.2-0.9 g / cm 3 The density of the carbon / carbon composite sheet obtained after chemical vapor carburization densification is 1.5-1.9g / cm 3 ; The device comprises a high-silica fiber microporous air guide plate, which is a high-silica fiber / carbon composite plate; The thickness of the high silica fiber microporous air guide plate is 3-12 mm, and the density is 0.2-1.5 g / cm 3 ; The diameter of the high-silica fiber in the high-silica fiber microporous air guide plate is 6-10µm, and its silicon oxide content is 96-98%; The preparation process of the high-silica fiber microporous air guide plate is as follows: needle-punching the high-silica fiber web into a flat felt, performing chemical vapor carburizing densification and hardening; and then machining to obtain the high-silica fiber microporous air guide plate; The thickness of the flat felt is 5-15 mm and the density is 0.09-0.12 g / cm 3 .

2. The method for preparing a carbon / carbon composite material sheet according to claim 1, wherein: The chemical vapor carburizing densification hardening process is: using C3H6 as carbon source gas, controlling the furnace temperature to 920-960°C and the furnace pressure to 1-12kPa, and accumulating chemical vapor carburizing for 10-300 hours before taking out of the furnace.

3. The method for preparing a carbon / carbon composite material sheet according to claim 1, wherein: The device also includes a hollow graphite plate, which is stacked with a high-silica fiber microporous air guide plate to form a support plate. A carbon / carbon composite material thin plate blank is sandwiched between the high-silica fiber microporous air guide plates of the two support plates, and the two support plates are fastened with fasteners to form a device for preparing carbon / carbon composite material thin plates.

4. The method for preparing a carbon / carbon composite material sheet according to claim 3, wherein: The thickness of the hollow graphite plate is 15-30 mm, and the hollow area accounts for 30-50% of the total area of ​​the graphite plate.

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