Preparation device and preparation method of a near-net-shaped large-sized carbon / carbon composite material

Abstract

The present invention relates to the technical field of composite material preparation, and particularly relates to a preparation device and a preparation method for near-net-shaped large-size carbon / carbon composites, including a vacuum pumping system, a resin high-pressure injection system, a heating system, an upper support plate, a lower support plate, a resin injection pipeline, an upper mold provided on the bottom surface of the upper support plate, a lower mold provided on the lower support plate, and an air extraction port provided on the upper mold. A fixed support column is provided on the lower support plate and is connected through a horizontal adjustment mounting assembly. A through hole adapted to the fixed support column is provided on the upper support plate. The resin injection pipeline passes through the upper mold and extends into the molding cavity formed by the closing of the upper mold and the lower mold. The resin injection pipeline includes a main injection pipeline and a plurality of branch injection pipelines connected to the main injection pipeline and evenly distributed from the upper part to the lower part of the molding cavity. The fixed support column penetrates through the through hole on the upper support plate to ensure the alignment of the fixed support column with the through hole on the upper support plate, which is convenient for actual operation.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and particularly relates to a preparation device and a preparation method for near-net-shaped large-size carbon / carbon composites. Background Art

[0002] Large-size single-crystal silicon furnace thermal field carbon materials are mainly prepared by weaving carbon fibers into preforms, and the preforms are prepared after densification. The weaving of the preforms is mainly made by layer-by-layer needling of carbon fiber non-woven fabrics and web tires. The thermal field materials include crucibles, flow guiding cylinders, heat preservation barrels, etc. The preparation of the preforms needs to be completed on the surface of the mold. At present, the size of the crucible can reach more than 40 inches. Since the density of the preform is between 0.43 - 0.60 g / cc, the density of the preform is low, and it is easy to deform during the preparation, packaging, and transportation processes. Therefore, a large amount of allowance is reserved for the inner and outer diameters during the preform preparation process (usually the single-sided tolerance is greater than 2 mm), and the allowance is removed during the machining process, resulting in a large amount of waste. Especially, the price of carbon fiber is high, and a large amount of surface removal increases the material preparation cost.

[0003] At the same time, in the traditional impregnation process, although multi-column impregnation is achieved, a large amount of resin remains in the impregnation tank during the impregnation process or overflows from the inside of the material during the curing process, reducing the carbon yield. This causes a large amount of resin waste, which is uneconomical and environmentally unfriendly. Among them, in the process of preparing near-net-shaped large-size carbon / carbon composites, the upper mold and the lower mold need to be closed. In the prior art, Chinese Patent No. CN215786085A discloses a side-punching guiding stamping die that is not easy to crack. Through the design of positioning columns, the movement trajectory of the upper mold can be limited. However, the inventor also found that during the actual assembly process, the positioning columns are fixedly installed on the lower mold. When the positioning holes on the upper mold are not aligned with the positioning columns, the positioning columns will rub against the positioning holes, and even the situation where the positioning columns cannot be inserted into the positioning holes may occur, resulting in the positioning columns being unusable and inconvenient to adjust the position of the positioning columns, having certain limitations. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a preparation device and a preparation method for near-net-shaped large-size carbon / carbon composites to solve the problem that it is inconvenient to adjust the position of the positioning columns when the positioning holes on the upper mold are not aligned with the positioning columns.

[0005] For the above purposes, the present invention provides a preparation device for near-net-shaped large-size carbon / carbon composite materials, which includes a vacuum pumping system, a resin high-pressure injection system, a heating system, an upper support plate, a lower support plate, a resin injection pipeline, an upper mold arranged on the bottom surface of the upper support plate, a lower mold arranged on the lower support plate, and an air extraction port arranged on the upper mold. A fixed support column is arranged on the lower support plate and connected through a horizontal adjustment installation component. A through hole adapted to the fixed support column is opened on the upper support plate. The resin injection pipeline passes through the upper mold and extends into the molding cavity formed by the clamping of the upper mold and the lower mold. The resin injection pipeline includes a main injection pipeline and a plurality of branch injection pipelines connected to the main injection pipeline and evenly distributed from the upper part to the lower part of the molding cavity. Mold heating rods are arranged inside and outside the molding cavity. The vacuum pumping system is connected to the air extraction port;

[0006] The horizontal adjustment installation component includes a control box arranged below the fixed support column. The control box is fixedly connected to the lower support plate. A movable seat is arranged below the fixed support column. The movable seat and the control box are connected through a horizontal sliding unit. A through hole adapted to the movable seat is opened on the control box. A first spherical groove is opened at the bottom of the movable seat. A first movable ball is arranged in the first spherical groove. A fixed plate is fixedly connected inside the control box. A spherical hole is opened on the fixed plate. A second movable ball is arranged in the spherical hole. The second movable ball and the first movable ball are connected through a telescopic rod. The movable seat and the fixed support column are connected through a fixing piece. A locking mechanism adapted to the second movable ball is arranged on the control box.

[0007] Optionally, the fixing piece includes a plug block fixedly installed on the top of the movable seat. A slot is opened at the bottom of the fixed support column. The top end of the plug block is located in the slot. A support is fixedly connected to the movable seat. A limit column penetrates through the support. The limit column penetrates through the fixed support column and the plug block. One end of the limit column is fixedly connected to a movable disc. A tension spring is sleeved outside the limit column. The two ends of the tension spring are respectively fixedly connected to the support and the movable disc.

[0008] Optionally, the locking mechanism includes a pressing plate sleeved outside the plug block. The top and bottom of the pressing plate are respectively in contact with the fixed support column and the movable seat. A threaded tube is arranged inside the control box. The bottom end of the threaded tube is connected to the inner wall of the control box through a bearing. A lead screw is arranged inside the threaded tube. The top end of the lead screw is fixedly connected to a support seat. A second spherical groove adapted to the second movable ball is opened on the support seat. A side plate is fixedly connected to one side of the support seat. A positioning column penetrates through the side plate. The top end of the positioning column is fixedly connected to the fixed plate. A worm gear is fixedly sleeved outside the threaded tube. A worm is arranged inside the control box and meshes with the worm gear. One end of the worm is connected to the inner wall of the control box through a bearing. The other end of the worm is fixedly connected to a gear. A rack is arranged inside the control box and meshes with the gear. The top end of the rack is in contact with the bottom of the pressing plate. The rack and the control box are connected through an elastic member.

[0009] Optionally, the elastic member includes a support portion fixedly installed on one side of the toothed plate. A fixing column penetrates through the support portion. The bottom end of the fixing column is fixedly connected to the inner wall of the bottom of the control box. A compression spring is sleeved outside the fixing column. Two ends of the compression spring are respectively fixedly connected to the support portion and the inner wall of the bottom of the control box.

[0010] Optionally, the horizontal sliding unit includes movable blocks symmetrically arranged on both sides of the movable seat. A sliding groove is formed on one side of the movable block close to the movable seat. A sliding plate is arranged in the sliding groove. One end of the sliding plate is fixedly connected to the movable seat. A guiding groove is formed on the top of the control box. A guiding block matched with the guiding groove is fixedly connected to the bottom of the movable block.

[0011] This specification also provides a preparation method of a near-net-shaped large-size carbon / carbon composite material, including:

[0012] The staff adjusts the position of the movable seat in the horizontal direction. The first movable ball rolls in the first spherical groove, and the inclination angle of the telescopic rod changes, so that the movable seat and the through hole on the upper support plate are in the same vertical position. After the position of the movable seat is adjusted, through the design of the locking mechanism, the second movable ball and the telescopic rod are fixed relative to the fixed plate, so that the telescopic rod maintains the current inclination angle and the movable seat maintains the current position. Through the design of the fixing member, the bottom end of the fixing column is fixedly connected to the movable seat, and at the same time the fixing column penetrates through the through hole on the upper support plate. Through the cooperation of the fixing column and the through hole, the vertical movement track of the upper support plate is limited. The large-size carbon / carbon composite material is prepared by using the HP-RTM process combined with the CVD process. The method of the HP-RTM process combined with the CVD process is to place the near-net-shaped crucible carbon fiber preform into the mold cavity, first make a carbon / carbon composite material intermediate through vacuum pumping, high-pressure injection molding and curing, and then obtain the carbon / carbon composite material after carbonization, heat treatment and chemical vapor deposition treatment. Among them, the method of vacuum pumping, high-pressure injection molding and curing is to pump the closed mold to below 1 kPa, inject the liquid resin or asphalt added with a curing agent, make the pressure reach 1.3-2.8 MPa, and then gradually change the temperature to 180-250 °C to complete curing. The viscosity of the liquid resin or asphalt is controlled to be 200-500 mPas at 40-90 °C before adding.

[0013] Optionally, the method of gradient variable heating to 180 - 250 °C includes two heating stages. The first heating stage is heating from room temperature to 120 °C with a heating rate of 22 - 30 °C / h; the second heating stage is heating from above 120 °C to 250 °C with a heating rate of 16 - 20 °C / h. The carbonization method is to put the carbon / carbon composite intermediate after vacuum injection molding and curing into a carbonization furnace, introduce nitrogen, and perform gradient variable heating to 740 - 760 °C, and keep it at 740 - 760 °C for 1.5 - 2 h. The method of gradient variable heating to 740 - 760 °C includes three heating stages. The first heating stage is within 250 °C with a heating rate of 75 - 100 °C / h; the second heating stage is heating from above 250 °C to 550 °C with a heating rate of 11 - 15 °C / h; the third heating stage is heating from above 550 °C to 760 °C with a heating rate of 24 - 30 °C / h.

[0014] Optionally, the heat treatment method is to put the carbon / carbon composite intermediate after carbonization into a high-temperature heat treatment furnace and perform gradient variable heating to 2100 - 2300 °C. The method of gradient variable heating to 2100 - 2300 °C includes three heating stages. The first heating stage is within 1000 °C with a heating rate of 350 - 450 °C / h; the second heating stage is heating from above 1000 °C to 1750 °C with a heating rate of 160 - 220 °C / h; the third heating stage is heating from above 1750 °C to 2300 °C with a heating rate of 110 - 140 °C / h.

[0015] Optionally, the chemical vapor deposition treatment method is to put the carbon / carbon composite intermediate after heat treatment into a chemical vapor deposition furnace, and under the atmosphere of natural gas or propane or propylene, introduce 0% - 30% of the dilution gas nitrogen and deposit for 50 - 120 h at a deposition temperature of 870 - 1180 °C.

[0016] Optionally, after the crucible carbon fiber preform is placed in the mold cavity, before vacuum pumping, the upper and lower molds after mold closing are heated to 40 - 60 °C. The preparation method of the crucible carbon fiber preform is to prepare a composite layer by non-woven fabric and needle punching of a wire mesh preform, and then prepare the crucible carbon fiber preform by layer-by-layer needle punching of the composite layer. The layer density of the composite layer is 10 - 16 layers / cm, the needle punching density is 15 - 20 needles / cm², and the overall density of the final crucible carbon fiber preform reaches 0.43 - 0.60 g / cc.

[0017] Advantages of the present invention:

[0018] 1. The staff adjusts the position of the movable seat horizontally. The first movable ball rolls in the first spherical groove, and the inclination angle of the telescopic rod changes, so that the movable seat and the through hole on the upper support plate are in the same vertical position. After the position of the movable seat is adjusted, through the design of the locking mechanism, the second movable ball and the telescopic rod are fixed relative to the fixed plate, so that the telescopic rod maintains the current inclination angle and the movable seat maintains the current position. Through the design of the fixing part, the bottom end of the fixed support column is fixedly connected to the movable seat, and at the same time the fixed support column passes through the through hole on the upper support plate to ensure that the fixed support column is aligned with the through hole on the upper support plate, which is convenient for actual operation;

[0019] 2. Compared with the traditional process, the present invention can effectively reduce the total tolerance of the inner and outer diameters of the composite material (from more than 8 mm to within 4 mm), improve the density uniformity of the carbon / carbon composite material, and has the advantages of long service life and small performance fluctuations between production batches. Moreover, it can avoid the phenomenon of a large amount of waste caused by removing uneven allowances of the inner and outer diameters, thereby saving the material preparation cost.

[0020] 3. Compared with the traditional process, the usage amount of the preform in the present invention is reduced by about 20 - 30% compared with the traditional process, the resin usage amount is reduced by more than 25 - 35% compared with the traditional process, and the machining time is reduced by about 50 - 70% compared with the traditional process.

[0021] 4. The preparation method of the present invention can effectively improve the density of the carbon / carbon composite material and avoid deformation during packaging and transportation.

[0022] 5. The preparation method of the present invention is suitable for the preparation of large-size carbon / carbon composite materials and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of the molding and curing system of the present invention;

[0025] Figure 2 It is a schematic diagram of the inner and outer diameter positions of the present invention;

[0026] Figure 3 It is a schematic structural diagram of the horizontal adjustment and installation component of the embodiment of the present invention;

[0027] Figure 4 It is a schematic structural diagram of the interior of the control box of the embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the movable seat structure according to an embodiment of the present invention;

[0029] Figure 6 Schematic diagram of the split structure of the threaded pipe and the lead screw according to an embodiment of the present invention;

[0030] Figure 7 Schematic diagram of the sectional structure of the movable seat according to an embodiment of the present invention.

[0031] The markings in the figure are:

[0032] 1. Crucible carbon fiber preform; 2. Mold heating rod; 3. Air extraction port; 4. Resin injection pipe; 5. Upper support plate; 6. Lower support plate; 7. Fixed support column; 8. Lower mold; 9. Upper mold; 10. Control box; 11. Movable seat; 12. First spherical groove; 13. First movable ball; 14. Second movable ball; 15. Fixed plate; 16. Spherical hole; 17. Guide block; 18. Expansion rod; 19. Insert block; 20. Insert slot; 21. Limit post; 22. Bracket; 23. Movable disc; 24. Tensile spring; 25. Pressing plate; 26. Rack; 27. Gear; 28. Worm; 29. Threaded pipe; 30. Worm gear; 31. Lead screw; 32. Support seat; 33. Second spherical groove; 34. Support part; 35. Fixed column; 36. Compression spring; 37. Movable block; 38. Chute; 39. Slide plate; 40. Guide groove; 41. Side plate; 42. Positioning post. Detailed implementation manners

[0033] In order to make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments.

[0034] A preparation device for near-net-shaped large-size carbon / carbon composites proposed in one or more embodiments of this specification, as Figures 1 to 7 shown, includes a vacuum pumping system, a resin high-pressure injection system, a heating system, an upper support plate 5, a lower support plate 6, a resin injection pipe 4, an upper mold 9 provided on the bottom surface of the upper support plate 5, a lower mold 8 provided on the lower support plate 6, and an air extraction port 3 provided on the upper mold 9. A fixed support column 7 connected through a horizontal adjustment mounting assembly is provided on the lower support plate 6. A through hole adapted to the fixed support column 7 is opened on the upper support plate 5. The resin injection pipe 4 passes through the upper mold 9 and extends into the molding cavity formed by the upper mold 9 and the lower mold 8 being closed. The resin injection pipe 4 includes a main injection pipe and a plurality of branch injection pipes connected to the main injection pipe and evenly distributed from the upper part to the lower part of the molding cavity. Mold heating rods 2 are provided inside and outside the molding cavity. The vacuum pumping system is connected to the air extraction port 3;

[0035] The horizontal adjustment installation assembly includes a control box 10 arranged below the fixed support column 7. The control box 10 is fixedly connected to the lower support plate 6. An activity seat 11 is arranged below the fixed support column 7. The activity seat 11 and the control box 10 are connected through a horizontal sliding unit. A through hole matching the activity seat 11 is opened on the control box 10. A first spherical groove 12 is opened at the bottom of the activity seat 11. A first movable ball 13 is arranged in the first spherical groove 12. A fixed plate 15 is fixedly connected inside the control box 10. A spherical hole 16 is opened on the fixed plate 15. A second movable ball 14 is arranged in the spherical hole 16. The second movable ball 14 and the first movable ball 13 are connected through a telescopic rod 18. The activity seat 11 and the fixed support column 7 are connected through a fixing member. A locking mechanism matching the second movable ball 14 is arranged on the control box 10. When the staff adjusts the position of the activity seat 11 in the horizontal direction, the first movable ball 13 rolls in the first spherical groove 12, and the inclination angle of the telescopic rod 18 changes, so that the activity seat 11 and the through hole on the upper support plate 5 are in the same vertical position. After the position of the activity seat 11 is adjusted, through the design of the locking mechanism, the second movable ball 14 and the telescopic rod 18 are fixed relative to the fixed plate 15, so that the telescopic rod 18 maintains the current inclination angle and the activity seat 11 maintains the current position. Through the design of the fixing member, the bottom end of the fixed support column 7 is fixedly connected to the activity seat 11, and at the same time, the fixed support column 7 penetrates through the through hole on the upper support plate 5 to ensure that the fixed support column 7 is aligned with the through hole on the upper support plate 5, which is convenient for actual operation.

[0036] In some optional specific embodiments, the fixing member includes a plug block 19 fixedly installed on the top of the movable seat 11. A slot 20 is formed at the bottom of the fixed support column 7. The top end of the plug block 19 is located within the slot 20. A bracket 22 is fixedly connected to the movable seat 11. A limiting column 21 penetrates through the bracket 22, and the limiting column 21 penetrates through the fixed support column 7 and the plug block 19. One end of the limiting column 21 is fixedly connected to a movable disc 23. A tension spring 24 is sleeved outside the limiting column 21. The two ends of the tension spring 24 are respectively fixedly connected to the bracket 22 and the movable disc 23. The locking mechanism includes a pressing plate 25 sleeved outside the plug block 19. The top and bottom of the pressing plate 25 are respectively in contact with the fixed support column 7 and the movable seat 11. A threaded tube 29 is provided inside the control box 10. The bottom end of the threaded tube 29 and the inner wall of the control box 10 are connected through a bearing. A lead screw 31 is provided inside the threaded tube 29. The top end of the lead screw 31 is fixedly connected to a support seat 32. A second spherical groove 33 matching with the second movable ball 14 is formed on the support seat 32. One side of the support seat 32 is fixedly connected to a side plate 41. A positioning column 42 penetrates through the side plate 41. The top end of the positioning column 42 is fixedly connected to the fixing plate 15. An external fixing sleeve of the threaded tube 29 is provided with a worm gear 30. A worm 28 meshing with the worm gear 30 is provided inside the control box 10. One end of the worm 28 and the inner wall of the control box 10 are connected through a bearing. The other end of the worm 28 is fixedly connected to a gear 27. A toothed plate 26 meshing with the gear 27 is provided inside the control box 10. And the top end of the toothed plate 26 is in contact with the bottom of the pressing plate 25. The toothed plate 26 and the control box 10 are connected through an elastic member. The elastic member includes a support portion 34 fixedly installed on one side of the toothed plate 26. A fixing column 35 penetrates through the support portion 34. The bottom end of the fixing column 35 is fixedly connected to the bottom inner wall of the control box 10. A compression spring 36 is sleeved outside the fixing column 35. The two ends of the compression spring 36 are respectively fixedly connected to the support portion 34 and the bottom inner wall of the control box 10;

[0037] After the position adjustment of the movable seat 11 is completed, the staff drives the movable disc 23 to move, and the tension spring 24 is in a stretched state, so that the limit post 21 disengages from the insertion block 19. The staff drives the pressing plate 25 to move, so that the insertion block 19 penetrates through the pressing plate 25. The pressing plate 25 is placed on the top of the movable seat 11. The staff drives the fixed support column 7 to move. The slot 20 on the fixed support column 7 is aligned with the insertion block 19. The staff drives the fixed support column 7 to move downward, so that the insertion block 19 is inserted into the slot 20. At the same time, the top and bottom of the pressing plate 25 are in contact with the fixed support column ⑦ and the movable seat 11 respectively. At the same time, the pressing plate 25 presses the toothed plate 26, and the toothed plate 26 drives the gear 27 and the worm 28 to rotate. The worm 28 drives the threaded pipe 29 to rotate through the worm gear 30, so that the lead screw 31 and the support seat 32 move upward. The second movable ball 14 is in close contact with the inner wall of the second spherical groove 33, so that the second movable ball 14 is fixed relative to the fixed plate 15. At the same time, the staff releases the movable disc 23, and the tension spring 24 drives the movable disc 23 and the limit post 21 to move, so that the limit post 21 penetrates through the insertion block 19 and the fixed support column 7, and the position adjustment of the movable seat 11 and the fixation between the fixed support column 7 and the movable seat 11 can be completed at the same time.

[0038] In some optional specific embodiments, the horizontal sliding unit includes movable blocks 37 symmetrically arranged on both sides of the movable seat 11. A sliding groove 38 is formed on the side of the movable block 37 close to the movable seat 11. A sliding plate 39 is arranged in the sliding groove 38. One end of the sliding plate 39 is fixedly connected to the movable seat 11. A guiding groove 40 is formed on the top of the control box 10. A guiding block 17 matched with the guiding groove 40 is fixedly connected to the bottom of the movable block 37. Through the design of the movable block 37, the sliding groove 38 and the sliding plate 39, the movable seat 11 can slide left and right in the horizontal direction. Through the design of the guiding block 17 and the guiding groove 40, the movable seat 11 can slide back and forth in the horizontal direction.

[0039] The embodiment of this specification also provides a preparation method of a near-net-shaped large-size carbon / carbon composite material, including the following steps:

[0040] The staff adjusts the position of the movable seat 11 in the horizontal direction. The first movable ball 13 rolls in the first spherical groove 12, and the inclination angle of the telescopic rod 18 changes, so that the movable seat 11 and the through hole on the upper support plate 5 are in the same vertical position. After the position of the movable seat 11 is adjusted, through the design of the locking mechanism, the second movable ball 14 and the telescopic rod 18 are fixed relative to the fixed plate 15, so that the telescopic rod 18 maintains the inclination angle at this time, and the movable seat 11 maintains the position at this time. Through the design of the fixing member, the bottom end of the fixed pillar 7 and the movable seat 11 are fixedly connected, and at the same time, the fixed pillar 7 passes through the through hole on the upper support plate 5. Through the cooperation of the fixed pillar 7 and the through hole, the trajectory of the vertical movement of the upper support plate 5 is limited. A large-size carbon / carbon composite material is prepared by the HP-RTM process combined with the CVD process. The method of the HP-RTM process combined with the CVD process is to place the near-net-shaped crucible carbon fiber preform 1 into the mold cavity. First, a carbon / carbon composite material intermediate is made by vacuum pumping, high-pressure injection molding and curing, and then the carbon / carbon composite material is obtained after carbonization, heat treatment and chemical vapor deposition treatment. Among them, the method of vacuum pumping, high-pressure injection molding and curing is to evacuate the closed mold to below 1 kPa, inject a liquid resin or pitch added with a curing agent, make the pressure reach 1.3 - 2.8 MPa, and then gradually change the temperature to 180 - 250 °C at a variable rate to complete the curing. The viscosity of the liquid resin or pitch before addition is controlled to be 200 - 500 mPas at 40 - 90 °C.

[0041] In some optional specific embodiments, the method of gradually changing the temperature to 180 - 250 °C includes two temperature-rising stages. The first temperature-rising stage is to raise the temperature from room temperature to 120 °C, and the temperature-rising rate is 22 - 30 °C / h; the second temperature-rising stage is to raise the temperature to 250 °C after exceeding 120 °C, and the temperature-rising rate is 16 - 20 °C / h. The method of carbonization is to put the carbon / carbon composite material intermediate after vacuum pumping, injection molding and curing into a carbonization furnace, introduce nitrogen, and gradually change the temperature to 740 - 760 °C at a variable rate, and keep it at 740 - 760 °C for 1.5 - 2 h. The method of gradually changing the temperature to 740 - 760 °C includes three temperature-rising stages. The first temperature-rising stage is within 250 °C, and the temperature-rising rate is 75 - 100 °C / h; the second temperature-rising stage is to raise the temperature to 550 °C after exceeding 250 °C, and the temperature-rising rate is 11 - 15 °C / h; the third temperature-rising stage is to raise the temperature to 760 °C after exceeding 550 °C, and the temperature-rising rate is 24 - 30 °C / h.

[0042] In some optional specific embodiments, the method of heat treatment is to put the carbonized carbon / carbon composite intermediate into a high-temperature heat treatment furnace and raise the temperature at a variable gradient to 2100 - 2300°C. The method of raising the temperature at a variable gradient to 2100 - 2300°C includes three temperature-raising stages. The first temperature-raising stage is within 1000°C, and the heating rate is 350 - 450°C / h; the second temperature-raising stage is after the temperature exceeds 1000°C and up to 1750°C, and the heating rate is 160 - 220°C / h; the third temperature-raising stage is after the temperature exceeds 1750°C and up to 2300°C, and the heating rate is 110 - 140°C / h.

[0043] In some optional specific embodiments, the method of chemical vapor deposition treatment is to put the heat-treated carbon / carbon composite intermediate into a chemical vapor deposition furnace. Under a natural gas or propane or propylene atmosphere, 0% - 30% of the dilution gas nitrogen is introduced, and the deposition is carried out for 50 - 120 h at a deposition temperature of 870 - 1180°C.

[0044] In some optional specific embodiments, after the crucible carbon fiber preform 1 is placed in the mold cavity, before vacuum pumping, the upper and lower molds after mold closing are heated to 40 - 60°C. The preparation method of the crucible carbon fiber preform 1 is to prepare a composite layer through non-woven fabric and web tire needle punching, and then stack and needle punch the composite layer to prepare the crucible carbon fiber preform 1. The layer density of the composite layer is 10 - 16 layers / cm, the needle punching density is 15 - 20 needles / cm², and the overall density of the final crucible carbon fiber preform 1 reaches 0.43 - 0.60 g / cc.

[0045] The HP-RTM process of the present invention performs corresponding operations using the above-mentioned molding and curing system. It uses thermosetting resin and low-cost medium-temperature or low-temperature pitch in combination with the chemical vapor deposition process, and prepares large-sized carbon / carbon composites by combining chemical vapor deposition, HP-RTM, carbonization, and high-temperature heat treatment methods. Specific examples are as follows.

[0046] Example 1

[0047] 1. Open the upper and lower molds, put in a 36-inch hot field material crucible carbon fiber preform, and reserve machining allowances of 0.5 - 1 mm for the inner and outer diameters respectively. The preform is prepared by stacking and needle punching non-woven fabric and web tire, with a density reaching 0.50 ± 0.02 g / cc. Put the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 50 ± 5°C.

[0048] 2. Vacuum pump to less than 0.5 kPa, and inject the liquid resin (furfural resin containing 6 - 8% phosphoric acid) added with a curing agent under pressure. The temperature of the liquid resin is controlled at 40 - 60°C, and the pressure reaches 2 - 2.2 MPa. The viscosity of the liquid resin before addition is controlled at 200 - 400 mPa·s when it is at 40 - 60°C.

[0049] 3. Heating and curing

[0050] Adopt step - by - step variable - speed heating and curing. First, heat up to 120°C at a rate of 23°C / h, and then heat up to 250 ± 10°C at a rate of 18°C / h. The viscosity of the injected resin is 200 - 400 mPa·s.

[0051] 4. Take out the carbon / carbon composite intermediate, put it into a carbonization furnace, introduce nitrogen, and heat up to 700 - 750°C. The heating process is as follows: heat from room temperature to 250°C at a rate of 78°C / h, heat from 250°C to 550°C at a rate of 12°C / h, heat from 550°C to 750°C at a rate of 25°C / h, and then keep it at 750°C for 3 hours.

[0052] 5. Put the carbonized carbon / carbon composite into a high - temperature heat treatment furnace and heat up to 2200°C; heat from room temperature to 1000°C at a rate of 380°C / h; heat from 1000°C to 1750°C at a rate of 170°C / h; heat from 1750°C to 2100 ± 30°C at a rate of 120°C / h. The density after the final heat treatment reaches 1.48 g / cc.

[0053] 6. Use machining and turning to remove the unevenness on the material surface, removing 0.3 - 0.5 mm from both the inner and outer diameter surfaces.

[0054] 7. Put the heat - treated carbon / carbon composite into CVD. Under a natural gas atmosphere, introduce 10% diluent gas nitrogen, with a deposition temperature of 1050 - 1180°C, deposit for 50 - 120 hours, and the deposition pressure is 5 - 10 kPa. The final density reaches 1.55 - 1.65 g / cc.

[0055] Example 2

[0056] 1. Open the upper and lower molds, put in a 36 - inch thermal field material crucible carbon fiber preform, with machining allowances of 0.5 - 1 mm reserved for the inner and outer diameters respectively. The preform is prepared by laminating and needling non - woven fabric and wire mesh, with a density reaching 0.50 ± 0.02 g / cc. Put the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 80 - 90°C.

[0057] 2. Evacuate to less than 0.5 kPa, and inject liquid medium - temperature pitch under pressure. The pitch temperature is 85 ± 5°C, and the pressure reaches 2.0 - 2 MPa. The viscosity of the pitch before addition is 200 - 400 mPa·s when controlled at 80 - 90°C.

[0058] 3. Heating and curing

[0059] Adopt step - type variable - speed heating and curing. First, heat up to 120°C at a rate of 25°C / h, and then heat up to 250 ± 10°C at a rate of 18°C / h. The viscosity of the injected asphalt is 200 - 400 mPa·s.

[0060] 4. Take out the carbon / carbon composite intermediate, put it into a carbonization furnace, introduce nitrogen, and heat up to 750°C. The heating process is as follows: from room temperature to 250°C at a heating rate of 76°C / h, from 250°C to 550°C at a heating rate of 12°C / h, from 550°C to 750°C at a heating rate of 26°C / h, and then hold at 750°C for 3 hours.

[0061] 5. Put the carbonized carbon / carbon composite into a high - temperature heat - treatment furnace and heat up to 2100 ± 30°C; heat from room temperature to 1000°C at a heating rate of 390°C / h; heat from 1000°C to 1750°C at a heating rate of 175°C / h; heat from 1750°C to 1900 ± 30°C at a heating rate of 125°C / h. The density after the final heat treatment reaches 1.50 g / cc - 1.55 g / cc.

[0062] 6. Machine - turn to remove the unevenness on the material surface, removing 0.5 mm from both the inner and outer diameter surfaces.

[0063] 7. Put the heat - treated carbon / carbon composite into CVD. Under a natural gas atmosphere, introduce 10% diluting gas nitrogen. The deposition temperature is 1050 - 1180°C, the deposition pressure is 5 - 10 kPa, deposit for 50 - 120 hours, and the final density reaches 1.55 - 1.65 g / cc.

[0064] Example 3

[0065] 1. Open the upper and lower molds, put in a 36 - inch hot - field material crucible carbon fiber preform. The machining allowances for the inner and outer diameters are respectively reserved 0.5 - 1 mm. The preform is prepared by laminating and needling non - woven fabric and mesh tire, with a density reaching 0.50 ± 0.02 g / cc. Put the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 50 ± 5°C.

[0066] 2. Evacuate to less than 0.5 kPa, and inject under pressure the liquid resin added with a curing agent (furfural resin containing 6 - 8% phosphoric acid). The temperature of the liquid resin is controlled at 40 - 60°C, and the pressure reaches 2 - 2.2 MPa. The viscosity of the liquid resin before adding is 200 - 400 mPa·s when controlled at 40 - 60°C.

[0067] 3. Heat up and cure

[0068] Adopt step - type variable - speed heating and curing. First, heat up to 120°C at a rate of 23°C / h, and then heat up to 250 ± 10°C at a rate of 19°C / h. The viscosity of the injected resin is 200 - 400 mPa·s.

[0069] 4. Take out the carbon / carbon composite intermediate, put it into a carbonization furnace, introduce nitrogen, and heat up to 700 - 750 degrees. The heating process is as follows: from room temperature to 250°C at a heating rate of 78°C / h, from 250°C to 550°C at a heating rate of 12°C / h, from 550°C to 750°C at a heating rate of 25°C / h, and then hold at 750°C for 3 hours.

[0070] 5. Put the carbonized carbon / carbon composite into a high - temperature heat treatment furnace and heat up to 2200°C; from room temperature to 1000°C at a heating rate of 380°C / h; from 1000°C to 1750°C at a heating rate of 170°C / h; from 1750°C to 2100 ± 30°C at a heating rate of 120°C / h. The density after the final heat treatment reaches 1.48 g / cc.

[0071] 6. Use machine turning to remove the unevenness on the material surface, and remove 0.3 - 0.5 mm from both the inner and outer diameter surfaces.

[0072] 7. Put the heat - treated carbon / carbon composite into a CVD, in a propane atmosphere, introduce 10% diluent gas nitrogen, the deposition temperature is 920 - 1030°C, deposit for 50 - 120 hours, the deposition pressure is 5 - 10 kPa, and the final density reaches 1.55 - 1.65 g / cc.

[0073] Example 4

[0074] 1. Open the upper and lower molds, put in a 36 - inch hot - field material crucible carbon fiber preform, reserve machining allowances of 0.5 - 1 mm for both the inner and outer diameters respectively. The preform is prepared by laminating and needling non - woven fabric and mesh tire, and the density reaches 0.50 ± 0.02 g / cc. Put the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 80 - 90°C.

[0075] 2. Evacuate to less than 0.5 kPa, and inject liquid medium - temperature pitch under pressure. The pitch temperature is 85 ± 5°C, and the pressure reaches 2.0 - 2 MPa. The viscosity of the liquid pitch is controlled to be 200 - 400 mPa·s at 80 - 90°C before adding.

[0076] 3. Heat up and cure

[0077] Adopt step - type variable - speed heating and curing. First, heat up to 120°C at a rate of 25°C / h, and then heat up to 250 ± 10°C at a rate of 12°C / h. The viscosity of the injected pitch is 200 - 400 mPa·s.

[0078] 4. Take out the carbon / carbon composite intermediate, place it in a carbonization furnace, introduce nitrogen, and heat it up to 750 °C. The heating process is as follows: heat from room temperature to 250 °C at a heating rate of 76 °C / h, heat from 250 °C to 550 °C at a heating rate of 12 °C / h, heat from 550 °C to 750 °C at a heating rate of 26 °C / h, and then hold at 750 °C for 3 hours.

[0079] 5. Place the carbonized carbon / carbon composite in a high-temperature heat treatment furnace and heat it up to 2100 ± 30 °C; heat from room temperature to 1000 °C at a heating rate of 390 °C / h; heat from 1000 °C to 1750 °C at a heating rate of 175 °C / h; heat from 1750 °C to 1900 ± 30 °C at a heating rate of 125 °C / h. The density after the final heat treatment reaches 1.50 g / cc - 1.55 g / cc.

[0080] 6. Use a lathe to machine and remove the unevenness on the material surface, removing 0.5 mm from both the inner and outer diameter surfaces.

[0081] 7. Place the heat-treated carbon / carbon composite in a CVD reactor. Under a propane atmosphere, introduce 10% dilution gas nitrogen. The deposition temperature is 920 - 1030 °C, the deposition pressure is 5 - 10 kPa, and the deposition time is 50 - 120 hours. The final density reaches 1.55 - 1.65 g / cc.

[0082] Example 5

[0083] 1. Open the upper and lower molds, place a 36-inch hot field material crucible carbon fiber preform, leaving machining allowances of 0.5 - 1 mm for the inner and outer diameters respectively. The preform is prepared by laminating and needling non-woven fabric and mesh tire, with a density reaching 0.50 ± 0.02 g / cc. Place the preform in the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 50 ± 5 °C.

[0084] 2. Evacuate to less than 0.5 kPa, and then inject the liquid resin (furfural resin containing 6 - 8% phosphoric acid) added with a curing agent under pressure. The temperature of the liquid resin is controlled at 40 - 60 °C, and the pressure reaches 2 - 2.2 MPa. The viscosity of the liquid resin before addition is controlled at 200 - 400 mPa·s at 40 - 60 °C.

[0085] 3. Heat for curing

[0086] Use staged variable-speed heating for curing. First, heat up to 120 °C at a heating rate of 23 °C / h, and then heat up to 250 ± 10 °C at a heating rate of 13 °C / h. The viscosity of the injected resin is 200 - 400 mPa·s.

[0087] 4. Take out the carbon / carbon composite intermediate, put it into a carbonization furnace, introduce nitrogen, and heat up to 700 - 750 °C. The heating process is as follows: heat from room temperature to 250 °C at a heating rate of 78 °C / h, from 250 °C to 550 °C at a heating rate of 12 °C / h, and from 550 °C to 750 °C at a heating rate of 25 °C / h. Then keep it at 750 °C for 3 hours.

[0088] 5. Put the carbonized carbon / carbon composite into a high-temperature heat treatment furnace and heat up to 2200 °C; heat from room temperature to 1000 °C at a heating rate of 380 °C / h; heat from 1000 °C to 1750 °C at a heating rate of 170 °C / h; heat from 1750 °C to 2100 ± 30 °C at a heating rate of 120 °C / h. The density after the final heat treatment reaches 1.48 g / cc.

[0089] 6. Use machining to turn and remove the unevenness on the material surface, removing 0.3 - 0.5 mm from both the inner and outer diameter surfaces.

[0090] 7. Put the heat-treated carbon / carbon composite into a CVD, introduce 10% dilution gas nitrogen under a propylene atmosphere, with a deposition temperature of 870 - 980 °C, deposit for 50 - 120 hours, and the deposition pressure is 5 - 10 kPa. The final density reaches 1.55 - 1.65 g / cc.

[0091] Example 6

[0092] 1. Open the upper and lower molds, put in a 36-inch hot field material crucible carbon fiber preform, leaving machining allowances of 0.5 - 1 mm for the inner and outer diameters respectively. The preform is prepared by laminating and needle punching non-woven fabric and wire mesh, with a density reaching 0.50 ± 0.02 g / cc. Put the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 80 - 90 °C.

[0093] 2. Evacuate to less than 0.5 kPa, and inject liquid medium-temperature pitch under pressure. The pitch temperature is 85 ± 5 °C, and the pressure reaches 2.0 - 2 MPa. Control the viscosity of the liquid pitch at 80 - 90 °C to be 200 - 400 mPa·s before adding.

[0094] 3. Heat up and cure

[0095] Adopt staged variable-speed heating and curing. First, heat up to 120 °C at a heating rate of 25 °C / h, and then heat up to 250 ± 10 °C at a heating rate of 12 °C / h. The viscosity of the injected pitch is 200 - 400 mPa·s.

[0096] 4. Take out the carbon / carbon composite intermediate, put it into a carbonization furnace, introduce nitrogen, and heat it up to 750 °C. The heating process is as follows: heat from room temperature to 250 °C at a heating rate of 76 °C / h, heat from 250 °C to 550 °C at a heating rate of 12 °C / h, heat from 550 °C to 750 °C at a heating rate of 26 °C / h, and then hold at 750 °C for 3 hours.

[0097] 5. Put the carbonized carbon / carbon composite into a high-temperature heat treatment furnace and heat it up to 2100 ± 30 °C; heat from room temperature to 1000 °C at a heating rate of 390 °C / h; heat from 1000 °C to 1750 °C at a heating rate of 175 °C / h; heat from 1750 °C to 1900 ± 30 °C at a heating rate of 125 °C / h. The density after the final heat treatment reaches 1.50 g / cc - 1.55 g / cc.

[0098] 6. Machine turning is used to remove the unevenness on the surface of the material, and 0.5 mm is removed from each of the inner and outer diameter surfaces.

[0099] 7. Put the heat-treated carbon / carbon composite into a CVD reactor. Under an atmosphere of propylene, introduce 10% of the dilution gas nitrogen. The deposition temperature is 870 - 980 °C, the deposition pressure is 5 - 10 kPa, and the deposition time is 50 - 120 hours. The final density reaches 1.55 - 1.65 g / cc.

[0100] Comparative Example 1

[0101] A carbon / carbon composite is prepared by using the traditional isothermal CVI process.

[0102] 1. For a 1.36-inch hot field material crucible carbon fiber preform, the machining allowances for the inner and outer diameters are respectively reserved at 3 - 4 mm. The preform is prepared by laminating and needle punching non-woven fabric and mesh tire, and the density reaches 0.50 ± ...

[0103] 2. Heat-treat the carbon / carbon composite intermediate at a high temperature of 1750 - 2000 °C for 2 ± 0.5 hours

[0104] 3. Process the carbon / carbon composite intermediate into the final size, removing 1 - 1.5 mm on one side.

[0105] 4. Put the processed carbon / carbon composite intermediate back into the CVD furnace for the second cycle of deposition. Under an atmosphere of natural gas, introduce 10% of the dilution gas nitrogen. The deposition temperature is 1050 - 1180 °C, the pressure is 5 - 10 kPa, and the deposition time is 150 - 200 hours. The final density reaches 1.38 - 1.52 g / cc.

[0106] Comparative Example 2

[0107] 1. Open the upper and lower molds, place the carbon fiber preform of the 36-inch hot field material crucible, leaving a machining allowance of 1 mm for the inner and outer diameters respectively. The preform is prepared by laminating and needling non-woven fabric and mesh tire, with a density reaching 0.50 g / cc. Place the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 50 °C.

[0108] 2. Evacuate to 0.5 kPa, and inject the liquid resin (furfural resin containing 4% phosphoric acid) added with a curing agent under pressure. The temperature of the liquid resin is controlled at 55 - 75 °C, and the pressure reaches 2.2 MPa. The viscosity of the liquid resin before addition is controlled to be above 500 mPa·s at 55 - 75 °C, and the viscosity during injection is above 500 mPa·s.

[0109] 3. Heat for curing

[0110] Adopt stepwise variable-speed heating for curing, first heat up to 250 ± 10 °C at a heating rate of 23 °C / h.

[0111] 4. Take out the carbon / carbon composite intermediate, place it into a carbonization furnace, introduce nitrogen, and heat up to 750 °C. The heating process is as follows: heat from room temperature to 750 °C at a heating rate of 50 °C / h, and then hold at 750 °C for 3 hours.

[0112] 5. Place the carbonized carbon / carbon composite into a high-temperature heat treatment furnace, and heat up to 2200 °C; heat from room temperature to 2300 °C at a heating rate of 300 °C / h. The density after the final heat treatment reaches 1.48 g / cc.

[0113] 6. Machine turn to remove the unevenness on the material surface, removing 0.5 mm from each of the inner and outer diameter surfaces.

[0114] 7. Place the heat-treated carbon / carbon composite into the CVD, under a natural gas atmosphere, introduce 10% of the dilution gas nitrogen, with a deposition temperature of 1050 - 1180 °C, and deposit for 80 - 120 hours. The final density reaches 1.45 - 1.55 g / cc.

[0115] Comparative Example 3

[0116] 1. Open the upper and lower molds, place the carbon fiber preform of the 36-inch hot field material crucible, leaving a machining allowance of 1 mm for the inner and outer diameters respectively. The preform is prepared by laminating and needling non-woven fabric and mesh tire, with a density reaching 0.50 g / cc. Place the preform into the mold cavity, close the mold, and heat the upper and lower molds until the temperature reaches 50 °C.

[0117] 2. Evacuate to less than 0.5 kPa, then inject liquid medium-temperature asphalt under pressure. The temperature of the asphalt is 55 ± 5 °C and the pressure reaches 2.0 - 2 MPa. The viscosity of the asphalt is above 500 mPa·s when controlled at 50 - 60 °C before addition and above 500 mPa·s during injection.

[0118] 3. Heat up and cure

[0119] Adopt staged variable-speed heating and curing. First, heat up to 250 ± 10 °C at a rate of 25 °C / h.

[0120] 4. Take out the carbon / carbon composite intermediate, put it into a carbonization furnace, introduce nitrogen, and heat up to 750 °C. The heating process is as follows: heat from room temperature to 750 °C at a heating rate of 50 °C / h, and then hold at 750 °C for 3 hours.

[0121] 5. Put the carbonized carbon / carbon composite into a high-temperature heat treatment furnace and heat up to 2200 °C; heat from room temperature to 2300 °C at a heating rate of 300 °C / h. The density after final heat treatment reaches 1.48 g / cc.

[0122] 6. Use a lathe to machine and remove the unevenness on the material surface, removing 0.5 mm from both the inner and outer diameter surfaces.

[0123] 7. Put the heat-treated carbon / carbon composite into a CVD device. Under a natural gas atmosphere, introduce 10% dilution gas nitrogen. The deposition temperature is 870 - 980 °C, the deposition pressure is 5 - 10 kPa, and deposit for 50 - 120 hours. The final density reaches 1.45 - 1.52 g / cc.

[0124] Perform inner and outer diameter density tests on the carbon / carbon composites prepared in Examples 1 - 6 and Comparative Examples 1 - 3. The test results are shown in Table 1 (where positions 1 - 5 are five position points selected from the outside to the inside).

[0125] Table 1

[0126]

[0127]

[0128] The comprehensive properties of the materials obtained by testing the materials in the region with the lowest central density of the carbon / carbon composites prepared in Examples 1 - 2 and Comparative Examples 1 - 6 are as follows in Table 2.

[0129]

[0130] From the above test results, it can be seen that the preparation method of the present invention has the best rate. In Comparative Examples 1-2, the viscosity of the resin and asphalt is high, and the fluidity is poor. The overall density gradient of the prepared composite material is large, and the performance is relatively poor. Due to the use of a more reasonable HP-RTM process in the present invention, the cutting amount of the inner and outer surfaces is reduced, from the previous single-sided tolerance of 2 mm to less than 1 mm, reducing the preparation cost of the material and at the same time reducing the density difference between the outer surface and the center of the material.

[0131] Working principle: The staff adjusts the position of the movable seat 11 in the horizontal direction. The first movable ball 13 rolls in the first spherical groove 12, and the inclination angle of the telescopic rod 18 changes, so that the movable seat 11 and the through hole on the upper support plate 5 are in the same vertical position. After the position of the movable seat 11 is adjusted, through the design of the locking mechanism, the second movable ball 14 and the telescopic rod 18 are fixed relative to the fixed plate 15, so that the telescopic rod 18 maintains the current inclination angle and the movable seat 11 maintains the current position. Through the design of the fixing member, the bottom end of the fixed support column 7 is fixedly connected to the movable seat 11, and at the same time the fixed support column 7 penetrates the through hole on the upper support plate 5. Through the cooperation of the fixed support column 7 and the through hole, the trajectory of the vertical movement of the upper support plate 5 is limited. Through the design of the movable block 37, the chute 38 and the sliding plate 39, the movable seat 11 can slide left and right in the horizontal direction. Through the design of the guiding block 17 and the guiding groove 40, the movable seat 11 can slide back and forth in the horizontal direction. After the position of the movable seat 11 is adjusted, the staff drives the movable disk 23 to move, and the tension spring 24 is in a stretched state, so that the limiting column 21 is disengaged from the insertion block 19. The staff drives the pressing plate 25 to move, so that the insertion block 19 penetrates the pressing plate 25. The pressing plate 25 is placed on the top of the movable seat 11. The staff drives the fixed support column 7 to move, and the slot 20 on the fixed support column 7 is aligned with the insertion block 19. The staff drives the fixed support column 7 to move downward, so that the insertion block 19 is inserted into the slot 20, and the top and bottom of the pressing plate 25 are in contact with the fixed support column 7 and the movable seat 11 respectively. At the same time, the pressing plate 25 presses the toothed plate 26, and the toothed plate 26 drives the gear 27 and the worm 28 to rotate. The worm 28 drives the threaded tube 29 to rotate through the worm gear 30, so that the lead screw 31 and the support seat 32 move upward. The second movable ball 14 is in close contact with the inner wall of the second spherical groove 33, so that the second movable ball 14 is fixed relative to the fixed plate 15. At the same time, the staff releases the movable disk 23, and the tension spring 24 drives the movable disk 23 and the limiting column 21 to move, so that the limiting column 21 penetrates the insertion block 19 and the fixed support column 7, and the adjustment of the position of the movable seat 11 and the fixation between the fixed support column 7 and the movable seat 11 can be completed simultaneously.

[0132] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; within the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

[0133] The present invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation device for near-net-shaped large-sized carbon / carbon composite materials, characterized in that, It includes a vacuum pumping system, a resin high-pressure injection system, a heating system, an upper support plate (5), a lower support plate (6), a resin injection pipeline (4), an upper mold (9) provided on the bottom surface of the upper support plate (5), a lower mold (8) provided on the lower support plate (6), and an air extraction port (3) provided on the upper mold (9). A fixed support column (7) connected through a horizontal adjustment installation component is provided on the lower support plate (6). A through hole adapted to the fixed support column (7) is opened on the upper support plate (5). The resin injection pipeline (4) passes through the upper mold (9) and extends into the molding cavity formed by the clamping of the upper mold (9) and the lower mold (8). The resin injection pipeline (4) includes a main injection pipeline and a plurality of branch injection pipelines connected to the main injection pipeline and uniformly arranged from the upper part to the lower part of the molding cavity. Mold heating rods (2) are provided both inside and outside the molding cavity. The vacuum pumping system is connected to the air extraction port (3); The horizontal adjustment installation component includes a control box (10) provided below the fixed support column (7). The control box (10) is fixedly connected to the lower support plate (6). A movable seat (11) is provided below the fixed support column (7). The movable seat (11) and the control box (10) are connected through a horizontal sliding unit. A through hole adapted to the movable seat (11) is opened on the control box (10). A first spherical groove (12) is opened at the bottom of the movable seat (11). A first movable ball (13) is provided in the first spherical groove (12). A fixing plate (15) is fixedly connected inside the control box (10). A spherical hole (16) is opened on the fixing plate (15). A second movable ball (14) is provided in the spherical hole (16). The second movable ball (14) and the first movable ball (13) are connected through a telescopic rod (18). The movable seat (11) and the fixed support column (7) are connected through a fixing member. A locking mechanism adapted to the second movable ball (14) is provided on the control box (10); The fixing member includes a plug (19) fixedly installed on the top of the movable seat (11). A slot (20) is opened at the bottom of the fixed support column (7). The top end of the plug (19) is located inside the slot (20). A support (22) is fixedly connected to the movable seat (11). A limit post (21) penetrates through the support (22), and the limit post (21) penetrates through the fixed support column (7) and the plug (19). A movable disc (23) is fixedly connected to one end of the limit post (21). A tension spring (24) is sleeved outside the limit post (21). The two ends of the tension spring (24) are respectively fixedly connected to the support (22) and the movable disc (23); The locking mechanism includes a pressing plate (25) sleeved outside the insertion block (19). The top and bottom of the pressing plate (25) are respectively in contact with the fixed support column (7) and the movable seat (11). A threaded pipe (29) is arranged in the control box (10). The bottom end of the threaded pipe (29) and the inner wall of the control box (10) are connected by a bearing. A lead screw (31) is arranged in the threaded pipe (29). The top end of the lead screw (31) is fixedly connected with a support seat (32). A second spherical groove (33) matching with the second movable ball (14) is formed on the support seat (32). One side of the support seat (32) is fixedly connected with a side plate (41). A positioning column (42) penetrates through the side plate (41). The top end of the positioning column (42) is fixedly connected with the fixing plate (15). A worm gear (30) is fixedly sleeved outside the threaded pipe (29). A worm (28) meshing with the worm gear (30) is arranged in the control box (10). One end of the worm (28) and the inner wall of the control box (10) are connected by a bearing. The other end of the worm (28) is fixedly connected with a gear (27). A toothed plate (26) meshing with the gear (27) is arranged in the control box (10). And the top end of the toothed plate (26) is in contact with the bottom of the pressing plate (25). The toothed plate (26) and the control box (10) are connected by an elastic member.

2. The preparation device of the near-net-shaped large-sized carbon / carbon composite material according to claim 1, characterized in that, The elastic member includes a support portion (34) fixedly installed on one side of the toothed plate (26). A fixing column (35) penetrates through the support portion (34). The bottom end of the fixing column (35) is fixedly connected with the bottom inner wall of the control box (10). A compression spring (36) is sleeved outside the fixing column (35). The two ends of the compression spring (36) are respectively fixedly connected with the support portion (34) and the bottom inner wall of the control box (10).

3. The preparation device for near-net-shaped large-sized carbon / carbon composite materials according to claim 1, wherein, The horizontal sliding unit includes movable blocks (37) symmetrically arranged on both sides of the movable seat (11). A sliding groove (38) is formed on the side of the movable block (37) close to the movable seat (11). A sliding plate (39) is arranged in the sliding groove (38). One end of the sliding plate (39) is fixedly connected with the movable seat (11). A guiding groove (40) is formed on the top of the control box (10). A guiding block (17) matching with the guiding groove (40) is fixedly connected with the bottom of the movable block (37).

4. A method for preparing a near-net-shaped large-sized carbon / carbon composite material, comprising the apparatus for preparing a near-net-shaped large-sized carbon / carbon composite material as described in claim 1, characterized in that, It includes the following steps: The staff adjusts the position of the horizontally movable seat (11). The first movable ball (13) rolls in the first spherical groove (12), and the inclination angle of the telescopic rod (18) changes, so that the movable seat (11) and the through hole on the upper support plate (5) are in the same vertical position. After the position of the movable seat (11) is adjusted, through the design of the locking mechanism, the second movable ball (14) and the telescopic rod (18) are fixed relative to the fixed plate (15), so that the telescopic rod (18) maintains the inclination angle at this time, and the movable seat (11) maintains the position at this time. Through the design of the fixing member, the bottom end of the fixed support (7) is fixedly connected to the movable seat (11), and at the same time, the fixed support (7) penetrates through the through hole on the upper support plate (5). Through the cooperation of the fixed support (7) and the through hole, the trajectory of the vertical movement of the upper support plate (5) is limited. A large-sized carbon / carbon composite material is prepared by the HP-RTM process combined with the CVD process. The method of the HP-RTM process combined with the CVD process is to place the near-net-shaped crucible carbon fiber preform (1) into the mold cavity, first make a carbon / carbon composite material intermediate through vacuum pumping, high-pressure injection molding and curing, and then obtain the carbon / carbon composite material after carbonization, heat treatment and chemical vapor deposition treatment. Among them, the method of vacuum pumping, high-pressure injection molding and curing is to evacuate the closed mold to below 1 kPa, inject liquid resin or pitch added with a curing agent, make the pressure reach 1.3 - 2.8 MPa, and then gradually change the temperature to 180 - 250 °C at a variable rate to complete the curing. The viscosity of the liquid resin or pitch before adding is controlled to be 200 - 500 mPas at 40 - 90 °C.

5. The preparation method of the near-net-shaped large-size carbon / carbon composite material according to claim 4, characterized in that, The method of gradually changing the temperature to 180 - 250 °C includes two temperature-rising stages. The first temperature-rising stage is to raise the temperature from room temperature to 120 °C, and the temperature-rising rate is 22 - 30 °C / h; the second temperature-rising stage is to raise the temperature to 250 °C after exceeding 120 °C, and the temperature-rising rate is 16 - 20 °C / h. The method of carbonization is to put the carbon / carbon composite material intermediate after vacuum pumping, injection molding and curing into a carbonization furnace, introduce nitrogen, and gradually change the temperature to 740 - 760 °C at a variable rate, and keep it warm for 1.5 - 2 h at 740 - 760 °C. The method of gradually changing the temperature to 740 - 760 °C includes three temperature-rising stages. The first temperature-rising stage is within 250 °C, and the temperature-rising rate is 75 - 100 °C / h; the second temperature-rising stage is to raise the temperature to 550 °C after exceeding 250 °C, and the temperature-rising rate is 11 - 15 °C / h; the third temperature-rising stage is to raise the temperature to 760 °C after exceeding 550 °C, and the temperature-rising rate is 24 - 30 °C / h.

6. The preparation method of the near-net-shaped large-size carbon / carbon composite material according to claim 4, wherein, The method of heat treatment is to put the carbonized carbon / carbon composite intermediate into a high-temperature heat treatment furnace and raise the temperature to 2100-2300°C at a variable gradient rate. The method of raising the temperature to 2100-2300°C at a variable gradient rate includes three heating stages. The first heating stage is within 1000°C, and the heating rate is 350-450°C / h; the second heating stage is after the temperature rises above 1000°C to 1750°C, and the heating rate is 160-220°C / h; the third heating stage is after the temperature rises above 1750°C to 2300°C, and the heating rate is 110-140°C / h.

7. The preparation method of the near-net-shaped large-size carbon / carbon composite material according to claim 4, characterized in that, The method of chemical vapor deposition treatment is to put the heat-treated carbon / carbon composite intermediate into a chemical vapor deposition furnace. Under the atmosphere of natural gas or propane or propylene, 0%-30% of the dilution gas nitrogen is introduced, and the deposition is carried out for 50-120h at a deposition temperature of 870-1180°C.

8. The preparation method of the near-net-shaped large-size carbon / carbon composite material according to claim 4, characterized in that, After the crucible carbon fiber preform (1) is placed in the mold cavity, before vacuum pumping, the upper and lower molds after clamping are heated to 40-60 °C. The preparation method of the crucible carbon fiber preform (1) is to prepare a composite layer by needling non-woven fabric and web, and stack and needle the composite layers to prepare the crucible carbon fiber preform (1). The layer density of the composite layer is 10-16 layers / cm, and the needling density is 15-20 needles / cm 2 , and finally the overall density of the crucible carbon fiber preform (1) reaches 0.43-0.60 g / cc.

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