Tool for chemical vapor infiltration process

Abstract

The utility model belongs to the technical field of carbon-carbon composite material preparation, and particularly relates to a tool for a chemical vapor infiltration process. The tool for the chemical vapor infiltration process comprises a to-be-treated prefabricated body group, wherein a through hole penetrating through the to-be-treated prefabricated body group is formed in the center of the to-be-treated prefabricated body group; the to-be-treated prefabricated body group comprises prefabricated body layers and flow guide layers which are alternately stacked; the prefabricated body layer comprises a prefabricated body to be treated; the flow guide layer comprises a plurality of flow guide gaskets which are uniformly arranged between the adjacent prefabricated body layers, and an airflow channel is formed between the adjacent flow guide gaskets; the carbon source gas release device comprises a gas outlet end, and the gas outlet end is located at the bottom of the through hole of the to-be-treated preform group; and the gas path spoiler covers the top of the to-be-treated prefabricated body group. When the tool is used for preparing the carbon-carbon composite material, the densification efficiency of the material can be improved, the preparation period is shortened, meanwhile, the utilization rate of a carbon source can be increased, and defects in the carbon-carbon composite material are reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of carbon-carbon composite material preparation, and particularly relates to a tooling for a chemical vapor infiltration process. Background Art

[0002] Carbon-carbon composite materials have the advantages of low density, high strength, good friction performance, dimensional stability, etc. They have been widely used in the fields of medical treatment, aerospace, automotive parts, etc., and have broad development prospects. The existing methods for preparing carbon-carbon composite materials include chemical vapor infiltration (CVI), precursor impregnation pyrolysis (PIP), chemical liquid vapor deposition (CLVI), etc. The main method used in industrial production is isothermal chemical vapor infiltration. However, the preparation cycle of isothermal chemical vapor infiltration is very long, and it may take thousands of hours depending on the product. For example, when preparing carbon-carbon brake discs, the density is increased to 1.75g / cm 3 It takes 1800 to 2100 hours. That is, when preparing carbon-carbon composite materials using the existing isothermal chemical vapor infiltration process, the densification efficiency is low, the carbon source utilization rate is low, the preparation cycle is long, and the cost is high, which greatly limits the expansion of the application market of carbon-carbon composite materials. Utility Model Content

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of low densification efficiency, low carbon source utilization, long preparation cycle and high cost when using chemical vapor infiltration process to prepare carbon-carbon composite materials in the existing technology, thereby providing a tooling for chemical vapor infiltration process.

[0004] To this end, the present invention provides the following technical solutions:

[0005] The utility model provides a tooling for a chemical vapor infiltration process, comprising: a preform group to be processed, wherein a through hole penetrating the preform group to be processed is provided at a center position of the preform group to be processed; the preform group to be processed comprises alternatingly stacked preform layers and guide layers; the preform layers comprise preforms to be processed; the guide layers comprise a plurality of guide gaskets uniformly arranged between adjacent preform layers, with air flow channels formed between adjacent guide gaskets; a carbon source gas release device, wherein the carbon source gas release device comprises an air outlet end, and the air outlet end is located at the bottom of the through hole of the preform group to be processed; and an air path baffle, wherein the air path baffle covers the top of the preform group to be processed.

[0006] The tooling for the chemical vapor infiltration process provided by the present invention has no requirements on the specifications of the preform. Typically, but not limitedly, the preform can be a thick piece, a sheet piece, a tubular piece, an annular piece, etc., and the shape of the outermost circle of the cross section of the preform can be circular, triangular, square, polygonal, etc.

[0007] Optionally, the guide gasket is in the shape of at least one of an arc and a straight line; the two ends of the guide gasket are respectively located at the inner edge and the outer edge of the preform layer; optionally, the guide gasket is arc-shaped.

[0008] Optionally, each guide layer includes 5 to 8 uniformly laid guide pads.

[0009] Optionally, the number of guide pads laid in each guide layer is the same, and the guide pads laid in each guide layer overlap in the vertical direction.

[0010] Optionally, when an arc-shaped guide gasket is used, at the intersection of the guide gasket and the inner edge of the preform layer, the angle between the tangent of the guide gasket and the radial direction of the inner edge of the preform is 90° to 140°.

[0011] Optionally, the guide gasket has a thickness of 2 to 6 mm and a width of 10 to 20 mm; according to the currently commonly used specifications of carbon-carbon composite materials, when using an arc-shaped guide gasket, the radius corresponding to the inner arc of the guide gasket is 300 to 500 mm; typically, but not limiting, the guide gasket can be prepared separately or cut from a finished ring.

[0012] Optionally, the guide gasket is arc-shaped; optionally, at the intersection of the guide gasket and the inner edge of the preform layer, the angle between the tangent of the guide gasket and the radial position of the inner edge of the preform is 90° to 140°.

[0013] Optionally, the gas outlet end of the carbon source gas release device includes a hollow cavity, and the side wall of the cavity is provided with holes; the gas outlet end is connected to the gas inlet end through a spiral gas inlet pipe.

[0014] Optionally, the holes include a first hole and a second hole arranged alternately; the diameter ratio of the first hole and the second hole is 1.5 to 2.5:1; optionally, the diameter range of the first hole is 4 to 7 mm; optionally, the number ratio of the first hole and the second hole is 1:0.8 to 1.2; further optionally, the diameter ratio of the first hole and the second hole is 2:1.

[0015] Optionally, the wall thickness of the cavity is 2 to 5 mm.

[0016] Optionally, the total length of the air intake duct is ≥1200 mm.

[0017] Optionally, it further includes an air inlet, which is located at the bottom of the tooling and is connected to the air inlet end of the carbon source gas release device.

[0018] Optionally, it also includes a preform placement table located at the bottom of the tooling, and the center position of the preform placement table has a through hole, and the through hole is used to place the carbon source gas release device; optionally, the cavity of the carbon source gas release device is higher than the upper surface of the preform placement table; further optionally, the upper surface of the carbon source gas release device is not higher than the upper surface of the second layer of preforms from the bottom up.

[0019] Optionally, the bottom of the preform group to be processed is a guide layer.

[0020] Optionally, a furnace shell is further included; optionally, an air outlet is provided on the top of the furnace shell.

[0021] The beneficial effects of the utility model are:

[0022] The utility model provides a tool for chemical vapor infiltration process, comprising: a preform group to be processed, wherein the center position of the preform group to be processed is provided with a through hole penetrating the preform group to be processed; the preform group to be processed comprises alternating preform layers and a guide layer; the preform layer comprises a preform to be processed; the guide layer comprises a plurality of guide gaskets evenly arranged between adjacent preform layers, with air flow channels formed between adjacent guide gaskets; a carbon source gas release device, wherein the carbon source gas release device comprises an air outlet end, wherein the air outlet end is located at the bottom of the through hole of the preform group to be processed; and an air path baffle, wherein the air path baffle covers the top of the preform group to be processed. Using this tool to prepare carbon-carbon composite materials can effectively improve the material densification efficiency, shorten the preparation cycle of carbon-carbon composite materials, and at the same time improve the utilization rate of the carbon source and reduce the generation of defects in the carbon-carbon composite materials. The tooling provided by this utility model utilizes specific assembly components, particularly the design of the guide plate and carbon source gas release device, to increase the contact area and contact time between the carbon source gas and the preform. This ensures uniform gas flow at the bottom and throughout the preform during deposition, thus avoiding frequent repositioning of preforms during deposition. A gas flow blocker covers the top of the preform group to be processed, helping to extend the residence time of the carbon source gas within the preform.

[0023] The utility model provides a tool for chemical vapor infiltration process. The number of guide gaskets laid in each guide layer is the same, and the guide gaskets laid in each guide layer overlap in the vertical direction, which can effectively prevent the preform from deforming during the preparation process.

[0024] The utility model provides a tooling for chemical vapor infiltration processes. The outlet end of the carbon source gas release device comprises a hollow cavity with holes in the sidewalls. The outlet end is connected to the inlet end via a spiral inlet conduit. The carbon source gas release device can improve the flow of gas within the furnace chamber, preventing a decrease in the deposition efficiency of some preforms. The spiral inlet conduit increases the time it takes for the carbon source gas to reach the interior of the tooling, preheating it. The hollow cavity with holes in the sidewalls effectively disperses the carbon source gas, allowing it to diffuse evenly within the tooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a schematic diagram of a tooling for the chemical vapor infiltration process of the present invention;

[0027] Figure 2 This is a schematic diagram of the placement of the guide vanes in the present invention;

[0028] Figure 3 This is a schematic diagram of the carbon source gas release device in the present invention;

[0029] Description of reference numerals:

[0030] 1-air inlet; 2-carbon source gas release device; 201-air inlet pipe; 202-cavity; 3-preform layer; 301-inner edge of the preform layer; 302-outer edge of the preform layer; 4-guide layer; 401-guide gasket; 5-gas path baffle; 6-furnace shell; 7-air outlet. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0032] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0034] Experimental drugs:

[0035] Preform: φ470mm×φ240mm×30mm, 0.45±0.05g / cm 3 , Jiangyou Tianqi Guangfeng New Materials Technology Co., Ltd.

[0036] Example 1

[0037] Reference below Figure 1 、 2 3. Describe the tooling for chemical vapor infiltration process according to an embodiment of the present invention.

[0038] The tooling for chemical vapor infiltration provided by the embodiment of the present invention comprises: a preform group to be processed, wherein a through hole penetrating the preform group to be processed is provided at a center position of the preform group to be processed; the preform group to be processed comprises alternatingly stacked preform layers 3 and guide layers 4; the preform layers 3 comprise preforms to be processed; the guide layers 4 comprise a plurality of guide pads 401 evenly arranged between adjacent preform layers 3, with air flow channels formed between adjacent guide pads 401;

[0039] A carbon source gas releasing device 2, the carbon source gas releasing device 2 comprising a gas outlet end, the gas outlet end being located at the bottom of the through hole of the preform group to be processed;

[0040] The gas path baffle 5 covers the top of the preform group to be processed.

[0041] In some embodiments, the guide gasket 401 is at least one of an arc shape and a straight line shape; two ends of the guide gasket 401 are respectively located at the inner edge 301 of the preform layer and the outer edge 302 of the preform layer.

[0042] In some embodiments, each guide layer 4 includes 5 to 8 uniformly laid guide pads 401 .

[0043] In some embodiments, the number of guide pads 401 laid in each guide layer 4 is the same, and the guide pads 401 laid in each guide layer 4 overlap in the vertical direction.

[0044] In some embodiments, when the guide gasket 401 is in an arc shape, at the intersection of the guide gasket 401 and the inner edge 301 of the preform layer, the angle between the tangent line of the guide gasket 401 and the radial direction of the inner edge 301 of the preform layer is 90° to 140°. Figure 2 ∠α in .

[0045] In some embodiments, the guide gasket 401 has a thickness of 2 to 6 mm and a width of 10 to 20 mm.

[0046] In some embodiments, the gas outlet of the carbon source gas release device 2 includes a hollow cavity 202 , and the sidewall of the cavity 202 is provided with holes; the gas outlet is connected to the gas inlet via a spiral gas inlet pipe 201 .

[0047] In some embodiments, the holes include first holes and second holes that are staggered; the diameter ratio of the first holes to the second holes is 1.5 to 2.5:1.

[0048] In some embodiments, the diameter of the first hole ranges from 4 to 7 mm.

[0049] In some embodiments, the ratio of the number of the first holes to the number of the second holes is 1:0.8-1.2.

[0050] In some embodiments, the diameter ratio of the first hole to the second hole is 2:1.

[0051] In some embodiments, the wall thickness of the cavity 202 is 2-5 mm.

[0052] In some embodiments, the total length of the air intake pipe 201 is ≥1200 mm.

[0053] In some embodiments, an air inlet 1 is further included. The air inlet 1 is located at the bottom of the tooling and is connected to the air inlet end of the carbon source gas release device 2 .

[0054] In some embodiments, a preform placement platform is further included at the bottom of the tooling. The center of the preform placement platform has a through hole, and the through hole is used to place the carbon source gas release device 2.

[0055] In some embodiments, the cavity 202 on the carbon source gas releasing device 2 is higher than the upper surface of the preform placement table.

[0056] In some embodiments, the bottom of the preform group to be processed is a guide layer 4 .

[0057] In some embodiments, a furnace shell 6 is further included; in some embodiments, an air outlet 7 is provided on the top of the furnace shell 6 .

[0058] Example 2

[0059] This embodiment provides a carbon-carbon composite material and a preparation method thereof, using the chemical vapor infiltration process tooling described in Example 1, specifically comprising:

[0060] A preform group to be processed, wherein a through hole is provided at the center of the preform group to be processed and extends through the preform group to be processed; the preform group to be processed comprises alternating preform layers 3 and a guide layer 4; the preform layer 3 comprises preforms to be processed; the guide layer 4 comprises six guide pads 401 evenly laid between adjacent preform layers 3, forming an airflow channel between adjacent guide pads 401, with the ends of the guide pads 401 respectively located at the inner edge 301 and the outer edge 302 of the preform layer. The number of guide pads 401 laid in each guide layer 4 is the same, and the guide pads 401 laid in each guide layer 4 overlap in the vertical direction. The bottom of the preform group to be processed is the guide layer 4.

[0061] A carbon source gas release device 2, the carbon source gas release device 2 includes a gas outlet end, the gas outlet end is located at the bottom of the through hole of the preform group to be processed, the gas outlet end includes a hollow cavity 202, the side wall of the cavity 202 is provided with a first hole and a second hole arranged in an alternating manner, the cavity 202 is higher than the upper surface of the preform placement table, the gas outlet end is connected to the gas inlet end through a spiral gas inlet pipe 201, and the gas inlet end is connected to the gas inlet 1.

[0062] The gas path baffle 5 covers the top of the preform group to be processed, helping to extend the residence time of the carbon source gas in the preforms.

[0063] The preform placement platform is located at the bottom of the tooling, and has a through hole at the center thereof, on which the carbon source gas release device 2 is placed.

[0064] The furnace shell 6 has an air outlet 7 at the top.

[0065] The wall thickness of the cavity 202 on the carbon source gas release device 2 used is 4 mm, the length of the spiral air inlet pipe 201 is 1400 mm, the number ratio of the first holes and the second holes is 1:1, the diameter ratio of the first holes and the second holes is 2:1, and the diameter of the first hole is 6 mm.

[0066] The guide gasket 401 used is made of graphite, has an arc shape, a thickness of 4 mm, and a width of 15 mm. At the intersection of the guide gasket 401 and the inner edge 301 of the preform layer, the angle ∠α between the tangent of the guide gasket 401 and the radial position of the inner edge 301 of the preform layer is 100°.

[0067] During assembly, the carbon source gas release device 2 is first placed in the through hole at the center of the preform placement table, and then the guide layer 4 and the preform layer 3 are stacked on the preform placement table in sequence. Finally, 9 layers of preform layers 3 and 10 layers of guide layers 4 are stacked, and then the gas path baffle 5 is covered on them.

[0068] In this embodiment, the target density of the preform is 1.75 g / cm 3 During the preparation, the temperature is controlled at 1000°C and the furnace pressure is 5kPa. The carbon source gas enters the carbon source gas release device 2 through the air inlet 1, is preheated in the air inlet pipe 201, and then enters the tooling for chemical vapor infiltration through the holes on the side wall of the cavity 202. The specific preparation method includes the following steps:

[0069] (1) The first stage: using natural gas and propane with a gas flow ratio of 4:1 as carbon source gas, a total gas flow of 50 L / min, and a carbon source utilization rate of 35%, the preform was densified to 1.2 g / cm 3 Second stage: using natural gas and propane with a gas flow ratio of 3:1 as carbon source gas, with a total gas flow of 25L / min and a carbon source utilization rate of 35%, and continuing to increase the density of the preform to 1.6g / cm 3 ; The third stage: using natural gas and propane with a gas flow ratio of 8:1 as the carbon source gas, a total gas flow of 15L / min, and a carbon source utilization rate of 15%, the preform is densified to the target density to obtain a carbon-carbon composite material.

[0070] (2) Detecting the carbon-carbon composite materials obtained in (1), screening out the carbon-carbon composite materials that have not yet reached the target density, and performing the fourth stage of densification: using natural gas and propane with a gas flow ratio of 20:1 as the carbon source gas, a total gas flow range of 5L / min, a carbon source utilization rate of 10%, and densification to the target density.

[0071] Example 3

[0072] This embodiment provides a carbon-carbon composite material and a preparation method thereof. The preform is densified to a target density of 1.5 g / cm using the chemical vapor infiltration process tooling described in Example 2. 3 During the preparation, the temperature is controlled at 950°C and the furnace pressure is 2kPa. The carbon source gas enters the carbon source gas release device 2 through the air inlet 1, is preheated in the air inlet pipe 201, and then enters the tooling for chemical vapor infiltration through the holes on the side wall of the cavity 202. The specific preparation method includes the following steps:

[0073] (1) The first stage: using natural gas and propane with a gas flow ratio of 5:1 as carbon source gas, a total gas flow of 36 L / min, and a carbon source utilization rate of 40%, the preform was densified to 1.1 g / cm 3 Second stage: using natural gas and propane with a gas flow ratio of 4:1 as carbon source gas, with a total gas flow of 18L / min and a carbon source utilization rate of 30%, and continuing to increase the density of the preform to 1.5g / cm 3 .

[0074] Example 4

[0075] This embodiment provides a carbon-carbon composite material and a preparation method thereof. The preform is densified to a target density of 1.3 g / cm using the chemical vapor infiltration process tooling described in Example 2. 3 During the preparation, the temperature is controlled at 1100°C and the furnace pressure is 10kPa. The carbon source gas enters the carbon source gas release device 2 through the air inlet 1, is preheated in the air inlet pipe 201, and then enters the tooling for chemical vapor infiltration through the holes on the side wall of the cavity 202. The specific preparation method includes the following steps:

[0076] Natural gas and propane with a gas flow ratio of 5:1 were used as carbon source gases, with a total gas flow of 55 L / min and a carbon source utilization rate of 40%. The preform was densified to 1.3 g / cm 3 .

[0077] Example 5

[0078] This embodiment provides a carbon-carbon composite material and a preparation method thereof. The only difference from Example 2 is that the guide layer 4 includes 8 guide gaskets 401 evenly arranged between adjacent preform layers 3, the wall thickness of the cavity 202 on the carbon source gas release device 2 used is 2 mm, the length of the spiral air intake pipe 201 is 1200 mm, the number ratio of the first holes and the second holes is 1:1, the diameter ratio of the first holes and the second holes is 2.5:1, and the diameter of the first hole is 4 mm; the material of the guide gasket 401 used is graphite, the shape is arc-shaped, the thickness is 6 mm, and the width is 10 mm. At the intersection of the guide gasket 401 and the inner edge 301 of the preform layer, the angle ∠α between the tangent of the guide gasket 401 and the radial position of the inner edge 301 of the preform layer is 90°.

[0079] Example 6

[0080] This embodiment provides a carbon-carbon composite material and a preparation method thereof. The only difference from Example 2 is that the guide layer 4 includes 5 guide gaskets 401 evenly arranged between adjacent preform layers 3, the wall thickness of the cavity 202 on the carbon source gas release device 2 used is 5 mm, the length of the spiral air intake pipe 201 is 1200 mm, the number ratio of the first holes and the second holes is 1:1, the diameter ratio of the first holes and the second holes is 1.5:1, and the diameter of the first hole is 7 mm; the material of the guide gasket 401 used is graphite, the shape is arc-shaped, the thickness is 2 mm, and the width is 20 mm. At the intersection of the guide gasket 401 and the inner edge 301 of the preform layer, the angle ∠α between the tangent of the guide gasket 401 and the radial position of the inner edge 301 of the preform layer is 140°.

[0081] Example 7

[0082] This embodiment provides a carbon-carbon composite material and a preparation method thereof. Compared with Example 2, the only difference is the specific preparation method:

[0083] (1) The first stage: using natural gas and propane with a gas flow ratio of 5:1 as carbon source gas, a total gas flow of 60L / min, and a carbon source utilization rate of 30%, the preform was densified to 1.3g / cm 3 Second stage: using natural gas and propane with a gas flow ratio of 4:1 as carbon source gas, with a total gas flow of 36L / min and a carbon source utilization rate of 40%, the preform is further densified to 1.7g / cm 3 ; The third stage: using natural gas and propane with a gas flow ratio of 5:1 as the carbon source gas, a total gas flow of 10L / min, and a carbon source utilization rate of 25%, the preform is densified to the target density to obtain a carbon-carbon composite material.

[0084] (2) Testing the carbon-carbon composite materials obtained in (1), screening out the carbon-carbon composite materials that have not yet reached the target density, and performing the fourth stage of densification: using natural gas and propane with a gas flow ratio of 10:1 as the carbon source gas, a total gas flow range of 10L / min, a carbon source utilization rate of 5%, and densification to the target density.

[0085] Example 8

[0086] This embodiment provides a method for preparing a carbon-carbon composite material. Compared with Example 2, the only difference is that in the tooling used for the chemical vapor infiltration process, the guide plate 401 is straight instead of arc-shaped, and the position of the straight guide plate 401 is the position of the chord corresponding to the arc-shaped guide plate 401.

[0087] Example 9

[0088] This embodiment provides a carbon-carbon composite material and a preparation method thereof. The only difference compared to Example 2 is that natural gas with a total gas flow rate of 30 L / min is used as the carbon source gas throughout the entire process.

[0089] Comparative Example 1

[0090] This comparative example provides a method for preparing a carbon-carbon composite material. Compared with Example 9, the only difference is that the preforms 3 are directly stacked in the furnace for subsequent densification operations.

[0091] Comparative Example 2

[0092] This comparative example provides a method for preparing a carbon-carbon composite material. Compared with Example 2, the only difference is that the preforms 3 are directly stacked in the furnace for subsequent densification operations.

[0093] Comparative Example 3

[0094] This comparative example provides a method for preparing a carbon-carbon composite material. Compared with Example 2, the difference is that the carbon source gas release device 2 is not used in the tooling for the chemical vapor infiltration process, and the carbon source gas directly enters the tooling through the air inlet 1; during the densification process, at 150 hours, the maximum density difference between the highest density carbon-carbon composite semi-finished product located at the upper layer and the lowest density carbon-carbon composite semi-finished product located at the lower layer has reached 0.504 g / cm 3 , it is necessary to take out all the semi-finished carbon-carbon composite materials and reload the furnace from bottom to top according to the density from low to high. The operation of taking out the semi-finished carbon-carbon composite materials and reloading the furnace needs to be repeated at the 300th and 400th hours to make the density of the final carbon-carbon composite material as uniform as possible.

[0095] Comparative Example 4

[0096] This comparative example provides a method for preparing a carbon-carbon composite material. Compared with Example 2, the only difference is that the air path baffle 5 is not used.

[0097] Test Example 1

[0098] The time taken to prepare the carbon-carbon composite materials in the examples and comparative examples was recorded. The time taken for preparing the carbon-carbon composite materials in Example 8 and Comparative Example 1 was the time taken for about 95% of the carbon-carbon composite materials to reach the target density.

[0099] The densification efficiency and carbon source utilization rate of the carbon-carbon composite materials prepared in the examples and comparative examples were calculated. The densification efficiency is the density increase of the product per unit time; the carbon source utilization rate = product weight increase / total carbon source weight per cycle.

[0100] The density uniformity of the single carbon-carbon composite materials prepared in the test examples and comparative examples was tested. The specific method was as follows: take a carbon-carbon composite material, divide it into 6 equal parts with the center of the circle as the center, take a group of samples radially in the middle of each part, with 4 sample points in each group, and the size of the sample point was 20mm×20mm square. Three samples with a height of 6mm were cut longitudinally from each sample point, for a total of 72 samples. The volume and mass of the samples were weighed and the theoretical average density was calculated. The maximum density-minimum density of the sample block was used as a reference for characterizing the density uniformity of the carbon-carbon composite material.

[0101] The results are shown in Table 1.

[0102] Table 1

[0103]

[0104]

[0105] As can be seen from Table 1, the densification efficiency and carbon source utilization of Examples 2 to 8 are better than those of Comparative Example 1 which does not use the tooling and the densification treatment method in this application, and Comparative Example 2 which does not use the tooling in this application but uses the densification treatment method in this application. Among them, because the deposition efficiency on the surface of the preform is better than that on the core of the preform during the densification process, and the atmospheric flow deposition will aggravate this process, the density uniformity of Examples 3 and 4 is poor when the density reaches the target density. Example 9 uses the tooling in this application, but does not use the densification treatment method in this application. It only uses 30L / min of natural gas as the carbon source gas. Due to the low carbon content in natural gas, objective reasons lead to a longer preparation time. However, compared with Comparative Example 1 which does not use the tooling and the densification treatment method in this application, it can be seen that Example 9 still has advantages in preparation time, densification efficiency, carbon source utilization, and density uniformity. The tooling in this application does have the effect of shortening preparation time, improving densification efficiency, carbon source utilization, and density uniformity. In Comparative Example 2, the tooling in this application is not used but the densification treatment method in this application is used. In theory, the densification treatment method in this application has a high densification efficiency, and the carbon source gas is mainly deposited by diffusion inside the preform. Therefore, when the tooling in this application is not used, the surface of the preform is easily sealed, thereby affecting the preparation process, and the density uniformity of the obtained carbon-carbon composite material is also poor. Although the preparation time of Comparative Example 3 is not long, the densification efficiency and carbon source utilization rate are also good, according to its preparation method, when the carbon source gas release device is not used, it is necessary to frequently stop the preparation process, take out the carbon-carbon composite semi-finished product to test the density, and reload the furnace according to the density. The process is cumbersome and not suitable for large-scale preparation. In Comparative Example 4, the gas path baffle 5 is not used. Due to the rapid escape of the carbon source gas, the preparation time is long, the densification efficiency, carbon source utilization rate, and density uniformity are poor.

[0106] Test Example 2

[0107] The mechanical properties of the carbon-carbon composite materials prepared in the Examples and Comparative Examples were tested, with reference to the standard HB.5434.9-2004 for tensile properties, HB.5434.5 for compression properties, HB.5434.6 for flexural properties, and ASTM D2344 for shear properties. The results are detailed in Table 2. The mechanical properties of the carbon-carbon composite materials obtained in Examples 5 and 6 were similar to those of Example 2 and are not specifically listed here. As can be seen from Table 2, the carbon-carbon composite materials prepared in the Examples of this application exhibited excellent mechanical properties.

[0108] Table 2

[0109]

[0110]

[0111] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A tool for chemical vapor infiltration process, characterized in that: include: A preform group to be processed, wherein a through hole is provided at the center of the preform group to be processed and penetrates the preform group to be processed; the preform group to be processed comprises alternatingly stacked preform layers and a guide layer; the preform layers comprise preforms to be processed; the guide layer comprises a plurality of guide pads evenly arranged between adjacent preform layers, and air flow channels are formed between adjacent guide pads; a carbon source gas releasing device, the carbon source gas releasing device comprising a gas outlet end, the gas outlet end being located at the bottom of the through hole of the preform group to be processed; An air path baffle plate covers the top of the preform group to be processed.

2. The chemical vapor infiltration tooling according to claim 1, characterized in that: The guide gasket is in the shape of at least one of an arc and a straight line; the two ends of the guide gasket are respectively located at the inner edge of the preform layer and the outer edge of the preform layer; And / or, each guide layer includes 5 to 8 uniformly laid guide pads; and / or, the number of guide pads laid in each guide layer is the same, and the guide pads laid in each guide layer overlap in the vertical direction; And / or, the guide gasket has a thickness of 2 to 6 mm and a width of 10 to 20 mm.

3. The chemical vapor infiltration tooling according to claim 2, characterized in that: The guide gasket is in an arc shape; And / or, at the intersection of the guide gasket and the inner edge of the preform layer, the angle between the tangent of the guide gasket and the radial direction of the inner edge of the preform is 90° to 140°.

4. The chemical vapor infiltration tooling according to claim 1, characterized in that: The gas outlet end of the carbon source gas release device comprises a hollow cavity, and the side wall of the cavity is provided with holes; the gas outlet end is connected to the gas inlet end through a spiral gas inlet pipe.

5. The chemical vapor infiltration tooling according to claim 4, characterized in that: The holes include first holes and second holes arranged alternately; the diameter ratio of the first holes to the second holes is 1.5 to 2.5:1; and / or, the wall thickness of the cavity is 2 to 5 mm; And / or, the total length of the air intake duct is ≥1200 mm.

6. The chemical vapor infiltration tooling according to claim 5, characterized in that: The diameter of the first hole ranges from 4 to 7 mm; and / or, the ratio of the number of the first holes to the number of the second holes is 1:0.8-1.2; And / or, the diameter ratio of the first hole to the second hole is 2:

1.

7. The tooling for chemical vapor infiltration process according to any one of claims 1 to 6, characterized in that: It also includes an air inlet, which is located at the bottom of the tooling and is connected to the air inlet end of the carbon source gas release device.

8. The tooling for chemical vapor infiltration process according to any one of claims 1 to 6, characterized in that: The bottom of the preform group to be processed is a guide layer.

9. The tooling for chemical vapor infiltration process according to any one of claims 1 to 6, characterized in that: It also includes a preform placement platform located at the bottom of the tooling, wherein the center of the preform placement platform has a through hole, and the through hole is used to place the carbon source gas release device; And / or, further comprising a furnace shell.

10. The tooling for chemical vapor infiltration process according to claim 9, characterized in that: The cavity of the carbon source gas release device is higher than the upper surface of the preform placement table; And / or, an air outlet is provided on the top of the furnace shell.

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