A method for producing a silicon carbide coating for carbon-carbon composites

Abstract

The application provides a preparation method of a silicon carbide coating for carbon-carbon composite materials and relates to the field of silicon carbide coatings. The preparation method of the silicon carbide coating for carbon-carbon composite materials is realized through a preparation device of the silicon carbide coating for carbon-carbon composite materials. The preparation device of the silicon carbide coating for carbon-carbon composite materials comprises a screw transmission mechanism, a machining end fixing frame is arranged at the middle position of the two side walls of the screw transmission mechanism, a machining mechanism is connected to the middle position of the front side wall of the machining end fixing frame through a bearing, and a machining end rotating gear is connected to the middle position of the front side wall of the machining mechanism. Through the use of the machining mechanism, the workpiece surface is prevented from being polluted during the process from spraying and washing to transfer, the probability of the carbon-carbon composite material contacting with particulate matter and metal scraps is greatly reduced, and thus the quality of the silicon carbide coating on the carbon-carbon composite material is improved.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide coating technology, specifically to a method for preparing a silicon carbide coating for carbon-carbon composite materials. Background Technology

[0002] Carbon / carbon composites are materials made by using carbon or graphite fibers as reinforcement and carbon or graphite as the matrix. Composed almost entirely of carbon, with covalent bonds between carbon atoms, they can withstand extremely high temperatures and rapid heating rates. In an inert atmosphere, carbon / carbon composites can operate for extended periods at temperatures up to 2000℃, making them the materials with the best high-temperature mechanical properties currently available. They are widely used in aerospace, aviation, nuclear energy, chemical, and medical fields. To improve the service life, oxidation resistance, and resistance to silicon vapor erosion of carbon / carbon composites, coatings are typically applied to their surface. Silicon carbide coatings are among the best coating materials for carbon / carbon composites, exhibiting high hardness, high wear resistance, high corrosion resistance, and high-temperature strength, thus enhancing the composite's wear resistance, corrosion resistance, and high-temperature resistance.

[0003] CN112679233B discloses a method for preparing a silicon carbide coating for carbon-carbon composite materials. The method first cleans the material surface to prevent dust, slag, and other particulate matter from adhering to the surface. Then, a primer, prepared by mixing graphite emulsion, a binder, a silicon carbide precursor resin and its curing agent, a reinforcing silicon carbide powder, and a suspending emulsifier, is applied to the carbon-carbon composite material. After drying, a second primer is sprayed on. After the second drying, the workpiece is placed in a ceramicizing furnace for ceramicizing treatment, thus obtaining a silicon carbide coating on the surface of the composite material. However, this method has limitations in obtaining the silicon carbide coating. During the process, it is necessary to strictly ensure that no particulate matter or metal debris adheres to the surface of the composite material. Otherwise, the silicon carbide coating will adhere to the particulate matter or metal debris, which will seriously affect the continuity of the silicon carbide coating. In the process from cleaning the workpiece to spraying the primer, the entire workpiece needs to be cleaned before it is moved to the primer spraying position. This makes it easy for the surface of the composite material to be contaminated with particulate matter or metal debris again, thereby reducing the quality of the finished silicon carbide coating. Therefore, those skilled in the art provide a method for preparing a silicon carbide coating for carbon-carbon composite materials to solve the above-mentioned problems. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a silicon carbide coating for carbon-carbon composite materials. This method solves the problem of easy contamination of the workpiece surface during the process from spraying to transportation, greatly reduces the probability of carbon-carbon composite materials coming into contact with particulate matter and metal debris, thereby improving the quality of the silicon carbide coating on carbon-carbon composite materials.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: A method for preparing a silicon carbide coating for carbon-carbon composite materials is implemented through a preparation device for a silicon carbide coating for carbon-carbon composite materials. The preparation device includes a lead screw drive mechanism. A processing end fixing frame is installed at the middle position of both side walls of the lead screw drive mechanism. A processing mechanism is connected to the middle position of the front side wall of the processing end fixing frame through a bearing. A processing end rotating gear is connected to the middle position of the front side wall of the processing mechanism. A top mounting frame is installed at the top of both side walls of the lead screw drive mechanism. A drying box is installed on both side walls of the lead screw drive mechanism, below the processing mechanism, and at the bottom inner side of the top mounting frame. An electric clamp is installed on the front side wall of the lead screw slider of the lead screw drive mechanism. The electric clamp holds a carbon-carbon composite material workpiece.

[0008] Preferably, the top mounting frame includes a main frame, a rack and pinion connecting frame, and a bevel connecting frame.

[0009] Preferably, the rack and pinion connector is fixedly connected to one side of the rear end face of the front side wall of the main frame, and the bevel connector is fixedly connected to the middle of the rear end face of the front side wall of the main frame.

[0010] Preferably, a composite rack is slidably connected within the rack connecting frame. One side wall of the composite rack has a straight rack, and the other side wall has a helical rack. The straight rack portion of one side wall of the composite rack meshes with the rotating gear at the processing end. A transmission bevel is mounted on one side wall of the bevel connecting frame near the top via a bearing. A linkage bevel is mounted on the middle of the rear end face of the front side wall of the main frame near the top via a bearing. The transmission bevel meshes with the linkage bevel, and the linkage bevel meshes with the helical rack portion of the composite rack. A transmission helical rack is slidably connected to the front side wall of the main frame below the transmission bevel, and the front half of the transmission helical rack meshes with the transmission bevel.

[0011] Preferably, the workpiece rotation mechanism includes a suspension, a top motor, a drive bevel gear, a turntable, a telescopic rod, and a contact head.

[0012] Preferably, the suspension is fixedly connected to the top position on the other side of the rear end face of the front side wall of the main frame, the top motor is bolted to the upper side wall of the suspension away from the main frame, the active toothed cone is located below the suspension and connected to the movable end of the top motor, the rear half of the transmission helical rack of the active toothed cone is engaged, the turntable is fixedly connected to the lower side of the active toothed cone, the telescopic rod is embedded in the lower side wall of the turntable, and the contact head is rotatably connected to the movable end of the telescopic rod.

[0013] Preferably, the processing mechanism includes an outer processing frame, an inner processing frame, two connecting heads, and four connecting cylinders.

[0014] Preferably, the four connecting cylinders are bolted to the middle positions of the top and bottom of the two side walls of the outer processing frame, and the two connecting heads are fixedly connected to the center of the upper and lower side walls of the inner processing frame. The two connecting heads are used in conjunction with the four connecting cylinders. Elastic scrubbing material is connected to both the inner side wall of the outer processing frame and the outer side wall of the inner processing frame. A base coat spray head is installed on the inner side of both side walls of the outer processing frame and the outer side of both side walls of the inner processing frame, above the elastic scrubbing material. A cleaning spray head is installed on the bottom position of the inner side of both side walls of the outer processing frame and the bottom position of the outer side walls of the inner processing frame. Trigger switches are provided on the bottom positions of both sides of the notch of the outer processing frame and above the elastic scrubbing material, as well as on the bottom position of the rear side wall of the inner processing frame and above the elastic scrubbing material. Several trigger switches located at the top are electrically connected to the base coat spray head, and several trigger switches located at the bottom are electrically connected to the cleaning spray head.

[0015] Preferably, the method for preparing the silicon carbide coating for the carbon-carbon composite material includes the following steps:

[0016] S1. Move the electric slider of the lead screw drive mechanism to the bottom, then clamp the carbon-carbon composite workpiece in the electric clamp, start the lead screw drive mechanism, and the electric clamp will drive the carbon-carbon composite workpiece to rise into the processing mechanism. At this time, the movable ends of the two connecting cylinders at the top will drive the locking blocks to lock in the connecting head at the top.

[0017] S2. When the two sides and the front part of the electric clamp make initial contact with several trigger switches located at the bottom, the cleaning nozzle starts to work and cleans the part of the carbon-carbon composite workpiece. When the part of the carbon-carbon composite workpiece moves between the two elastic scrubbing materials, the two elastic scrubbing materials are squeezed and deformed and come into contact with the carbon-carbon composite workpiece, wiping away the water adhering to the inner and outer surfaces of the carbon-carbon composite workpiece. When the two sides and the front part of the electric clamp make initial contact with several trigger switches at the top, the primer nozzle starts to work and sprays the primer onto the inner and outer surfaces of the carbon-carbon composite workpiece. The two elastic scrubbing materials also block the upper and lower cavities inside the processing mechanism to prevent the airflow and water flow in the lower cavity from affecting the workpiece spraying operation in the upper cavity.

[0018] S3. When the two sides and the front part of the electric clamp contact the trigger switches at the bottom again, the cleaning nozzle stops working, the workpiece is cleaned, and the moving ends of the two connecting cylinders at the top retract. The moving ends of the two connecting cylinders at the bottom drive the locking block to lock in the connector at the bottom. Then the workpiece continues to rise until the two sides and the front part of the electric clamp contact the trigger switches at the top again. At this time, the primer spray nozzle stops working, and the workpiece completes the cleaning and primer spraying of the inner and outer parts of both sides.

[0019] S4. After the workpiece has been cleaned and primed on both sides, the screw drive mechanism will drive the workpiece to continue to rise into the top drying box to dry the primed material sprayed on the workpiece. After drying, the screw drive mechanism will drive the workpiece to continue to rise to the top of the top mounting frame.

[0020] S5. When the lead screw drive mechanism drives the carbon-carbon composite workpiece to the top position of the top mounting bracket, the electric clamp loosens, and then the telescopic rod drives the contact head to extend and press the contact head tightly against the front side wall of the carbon-carbon composite workpiece. Then the top motor drives the turntable to rotate, thereby rotating the carbon-carbon composite workpiece ninety degrees. After the rotation is completed, the electric clamp clamps the material again.

[0021] S6. When the turntable rotates, the active toothed cone, which is fixedly connected to the top of the turntable, rotates along with it. The active toothed cone drives the transmission helical rack that meshes with it to move, thereby driving the rotation of the transmission toothed cone and the linkage toothed cone that meshes with the transmission toothed cone. Under the drive of the linkage toothed cone, the composite rack is raised and lowered. When the composite rack is raised and lowered, the straight tooth part of the composite rack drives the rotating gear at the processing end to rotate, thereby rotating the processing mechanism by 180 degrees, causing the cleaning nozzle of the processing mechanism to face upward and the base material nozzle to face downward.

[0022] S7. After the machining mechanism is turned and the carbon-carbon composite workpiece is rotated 90 degrees, the lead screw transmission mechanism drives the carbon-carbon composite workpiece to be conveyed downwards, and repeats steps S and S until the inner and outer surfaces of the carbon-carbon composite workpiece are cleaned, dried and coated with primer.

[0023] S8. After the inner and outer surfaces of the carbon-carbon composite workpiece have been cleaned, dried and coated with primer, the screw drive mechanism drives the carbon-carbon composite workpiece to the drying box at the bottom for secondary drying.

[0024] S9. After drying, remove the carbon-carbon composite workpiece from the electric clamp, and then place it in a magnetizing furnace for ceramic treatment to obtain a silicon carbide coating on the surface of the carbon-carbon composite workpiece.

[0025] (III) Beneficial Effects

[0026] This invention provides a method for preparing a silicon carbide coating for carbon-carbon composite materials. It possesses the following key technical features and beneficial effects:

[0027] This method combines spraying and primer application simultaneously, preventing contamination of the workpiece surface during the spraying and transport process. This significantly reduces the probability of contact between the carbon-carbon composite material and particulate matter and metal debris, thereby improving the quality of the silicon carbide coating on the carbon-carbon composite material. First, an electric clamp holds the carbon-carbon composite material for which the silicon carbide coating is to be applied. Then, a screw drive mechanism moves the carbon-carbon composite material upwards. When the electric clamp first contacts the trigger switch at the bottom, the cleaning nozzle starts working, cleaning specific areas of the carbon-carbon composite workpiece. As the carbon-carbon composite material rises, an elastic scrubbing agent wipes the cleaned areas. The moisture remaining on the surface of the composite material is sprayed onto the surface of the composite material through the primer nozzle after the part continues to rise. At this time, the lower half of the composite material is still being cleaned, while the upper half of the composite material has completed the primer spraying work. The upper and lower parts are sealed by elastic scrubbing material to prevent the airflow and water generated during cleaning from affecting the primer spraying. When the composite material rises to the top, the composite material is rotated by the workpiece rotation mechanism. At the same time, the driving force of the top motor completes the 180-degree rotation of the processing mechanism. It is no longer necessary to reset the composite material to the bottom and rise again, which greatly reduces the processing time of the composite material and prevents the newly formed film layer on the surface of the composite material from being scratched off by the elastic scrubbing material. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the back of the present invention;

[0030] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0031] Figure 4 This is a first top view of the present invention;

[0032] Figure 5 for Figure 4 A cross-sectional view along BB;

[0033] Figure 6 This is a schematic diagram of the concealed processing end fixing frame of the present invention;

[0034] Figure 7 for Figure 6 Enlarged view of point C in the middle;

[0035] Figure 8 This is a second top view of the present invention;

[0036] Figure 9 for Figure 8 A magnified schematic diagram along DD.

[0037] Among them, 1. Screw drive mechanism; 200. Machining mechanism; 3. Machining end fixing frame; 4. Machining end rotating gear; 5. Composite rack; 600. Top mounting frame; 7. Drying oven; 800. Workpiece rotating mechanism; 9. Transmission bevel gear; 10. Transmission helical rack; 11. Linkage bevel gear; 12. Electric clamp; 13. Carbon-carbon composite workpiece;

[0038] 201. External processing frame; 202. Internal processing frame; 203. Connector; 204. Connecting cylinder; 205. Base coat spray nozzle; 206. Elastic scrubbing material; 207. Cleaning nozzle; 208. Trigger switch;

[0039] 601. Main frame; 602. Rack and pinion connector; 603. Bevel connector;

[0040] 801. Suspension; 802. Top motor; 803. Active bevel gear; 804. Turntable; 805. Telescopic rod; 806. Contact head. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1:

[0043] like Figure 1-9 As shown, this embodiment of the invention provides a method for preparing a silicon carbide coating for carbon-carbon composite materials. The method for preparing the silicon carbide coating for carbon-carbon composite materials is realized by a preparation device for preparing the silicon carbide coating for carbon-carbon composite materials. The preparation device for preparing the silicon carbide coating for carbon-carbon composite materials includes a lead screw drive mechanism 1. A processing end fixing frame 3 is installed at the middle position of both side walls of the lead screw drive mechanism 1. A processing mechanism 200 is connected to the middle position of the front side wall of the processing end fixing frame 3 via a bearing. A processing end rotating gear 4 is connected to the middle position of the front side wall of the processing mechanism 200. A top mounting frame 600 is installed at the top of both side walls of the lead screw drive mechanism 1. A drying box 7 is installed on both side walls of the lead screw drive mechanism 1 below the processing mechanism 200 and at the bottom inner side of the top mounting frame 600. An electric clamp 12 is installed on the front side wall of the lead screw slider of the lead screw drive mechanism 1. The electric clamp 12 holds a carbon-carbon composite material workpiece 13.

[0044] The top mounting bracket 600 includes a main frame 601, a rack and pinion connecting bracket 602, and a bevel connecting bracket 603. The rack and pinion connecting bracket 602 is fixedly connected to one side of the rear end face of the front side wall of the main frame 601. The bevel connecting bracket 603 is fixedly connected to the middle of the rear end face of the front side wall of the main frame 601. A composite rack 5 is slidably connected inside the rack and pinion connecting bracket 602. One side wall of the composite rack 5 has a straight rack, and the other side wall of the composite rack 5 has an oblique rack. The straight rack portion of one side wall of the composite rack 5 is connected to the rack and pinion connecting bracket 602. The working end rotating gear 4 meshes, and a transmission tooth cone 9 is installed on one side wall of the tooth cone connecting frame 603 near the top position via a bearing. A linkage tooth cone 11 is installed on the middle of the rear end face of the front side wall of the main frame 601 near the top position via a bearing. The transmission tooth cone 9 meshes with the linkage tooth cone 11. The linkage tooth cone 11 meshes with the helical rack portion of the composite rack 5. A transmission helical rack 10 is slidably connected to the front side wall of the main frame 601 and below the transmission tooth cone 9. The front half of the transmission helical rack 10 meshes with the transmission tooth cone 9.

[0045] The workpiece rotation mechanism 800 includes a suspension 801, a top motor 802, a drive bevel gear 803, a turntable 804, a telescopic rod 805, and a contact head 806. The suspension 801 is fixedly connected to the top position on the other side of the rear end face of the front side wall of the main frame 601. The top motor 802 is bolted to the upper side wall of the suspension 801 at the end away from the main frame 601. The drive bevel gear 803 is located below the suspension 801 and is connected to the movable end of the top motor 802. The rear half of the transmission helical rack 10 of the drive bevel gear 803 is engaged. The turntable 804 is fixedly connected to the lower side of the drive bevel gear 803. The telescopic rod 805 is embedded in the lower side wall of the turntable 804. The contact head 806 is rotatably connected to the movable end of the telescopic rod 805.

[0046] The processing mechanism 200 includes an outer processing frame 201, an inner processing frame 202, two connectors 203, and four connecting cylinders 204. The four connecting cylinders 204 are bolted to the middle positions of the top and bottom of the two side walls of the outer processing frame 201, respectively. The two connectors 203 are fixedly connected to the centers of the upper and lower side walls of the inner processing frame 202, respectively. The two connectors 203 cooperate with the four connecting cylinders 204. Elastic scrubbing material 206 is attached to the inner side wall of the outer processing frame 201 and the outer side wall of the inner processing frame 202. The inner sides of the two side walls of the outer processing frame 201 and the outer sides of the two side walls of the inner processing frame 202 are located at... A base coat nozzle 205 is installed above the elastic scrubbing material 206. Cleaning nozzles 207 are installed on the bottom side of the inner side of both sides of the outer processing frame 201 and the bottom side of both sides of the inner processing frame 202. Trigger switches 208 are installed on the bottom side of both sides of the notch of the outer processing frame 201 and above the elastic scrubbing material 206, as well as on the bottom of the rear side wall of the inner processing frame 202 and above the elastic scrubbing material 206. Several trigger switches 208 located above are electrically connected to the base coat nozzles 205, and several trigger switches 208 located below are electrically connected to the cleaning nozzles 207.

[0047] The method for preparing a silicon carbide coating for carbon-carbon composite materials includes the following steps:

[0048] S1. Move the electric slider of the lead screw drive mechanism 1 to the bottom, then clamp the carbon-carbon composite workpiece 13 in the electric clamp 12, start the lead screw drive mechanism 1, and the electric clamp 12 drives the carbon-carbon composite workpiece 13 to rise into the processing mechanism 200. At this time, the movable ends of the two connecting cylinders 204 at the top drive the locking blocks to lock in the connecting head 203 at the top.

[0049] S2. When the two sides and the front part of the electric clamp 12 first contact with the trigger switches 208 located at the bottom, the cleaning nozzle 207 starts to work and cleans the part of the carbon-carbon composite workpiece 13. When the part of the carbon-carbon composite workpiece 13 moves between the two elastic scrubbing materials 206, the two elastic scrubbing materials 206 are squeezed and deformed and contact the carbon-carbon composite workpiece 13, and wipe the water adhering to the inner and outer surfaces of the carbon-carbon composite workpiece 13. When the two sides and the front part of the electric clamp 12 first contact with the trigger switches 208 at the top, the primer nozzle 205 starts to work and sprays the primer on the inner and outer surfaces of the carbon-carbon composite workpiece 13. The two elastic scrubbing materials 206 block the upper and lower cavities inside the processing mechanism 200 to prevent the airflow and water flow in the lower cavity from affecting the workpiece spraying operation in the upper cavity.

[0050] S3. When the two sides and the front part of the electric clamp 12 come into contact with the trigger switches 208 at the bottom again, the cleaning nozzle 207 stops working, the workpiece is cleaned, and the movable ends of the two connecting cylinders 204 at the top retract. The movable ends of the two connecting cylinders 204 at the bottom drive the locking block to lock in the connector 203 at the bottom. Then the workpiece continues to rise until the two sides and the front part of the electric clamp 12 come into contact with the trigger switches 208 at the top again. At this time, the primer spray nozzle 205 stops working, and the workpiece completes the cleaning and primer spraying of the inner and outer parts of both sides.

[0051] S4. After the workpiece has been cleaned and the base coat has been applied to the inner and outer sides, the screw drive mechanism 1 will drive the workpiece to continue to rise into the top drying box 7 to dry the base coat applied to the workpiece. After drying, the screw drive mechanism 1 will drive the workpiece to continue to rise to the top of the top mounting bracket 600.

[0052] S5. When the lead screw drive mechanism 1 drives the carbon-carbon composite workpiece 13 to the top position of the top mounting bracket 600, the electric clamp 12 loosens, and then the telescopic rod 805 drives the contact head 806 to extend and press the contact head 806 tightly against the front side wall of the carbon-carbon composite workpiece 13. Then the top motor 802 drives the turntable 804 to rotate, thereby rotating the carbon-carbon composite workpiece 13 by ninety degrees. After the rotation is completed, the electric clamp 12 clamps the material again.

[0053] S6. When the turntable 804 rotates, the active toothed cone 803, which is fixedly connected to the top of the turntable 804, rotates accordingly. The active toothed cone 803 drives the transmission helical rack 10 that meshes with it to move, thereby driving the transmission toothed cone 9 and the linkage toothed cone 11 that meshes with the transmission toothed cone 9 to rotate. Under the drive of the linkage toothed cone 11, the composite rack 5 is raised and lowered. When the composite rack 5 is raised and lowered, the straight tooth part of the composite rack 5 drives the processing end rotating gear 4 to rotate, thereby rotating the processing mechanism 200 by 180 degrees, causing the cleaning nozzle 207 of the processing mechanism 200 to face upward and the base material nozzle 205 to face downward.

[0054] S7. After the machining mechanism 200 has been turned and the carbon-carbon composite workpiece 13 has been rotated 90 degrees, the lead screw transmission mechanism 1 drives the carbon-carbon composite workpiece 13 to be conveyed downwards, and repeats steps S2 and S3 until the inner and outer surfaces of the carbon-carbon composite workpiece 13 have been cleaned, dried and coated with primer.

[0055] S8. After the inner and outer surfaces of the carbon-carbon composite workpiece 13 have been cleaned, dried and coated with a base coat, the lead screw drive mechanism 1 drives the carbon-carbon composite workpiece 13 to the drying box 7 at the bottom for secondary drying.

[0056] S9. After drying, remove the carbon-carbon composite workpiece 13 from the electric clamp 12, and then place the carbon-carbon composite workpiece 13 into a magnetizing furnace for ceramic treatment, so that a silicon carbide coating can be obtained on the surface of the carbon-carbon composite workpiece 13.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a silicon carbide coating for carbon-carbon composite materials, characterized in that: The method for preparing the silicon carbide coating for carbon-carbon composite materials is realized by a preparation device for the silicon carbide coating for carbon-carbon composite materials. The preparation device includes a screw drive mechanism (1), a processing end fixing frame (3) is installed at the middle position of the two side walls of the screw drive mechanism (1), a processing mechanism (200) is connected to the middle position of the front side wall of the processing end fixing frame (3) through a bearing, a processing end rotating gear (4) is connected to the middle position of the front side wall of the processing mechanism (200), and a top mounting frame is installed at the top of the two side walls of the screw drive mechanism (1). 600), drying boxes (7) are installed on both sides of the lead screw transmission mechanism (1) and below the processing mechanism (200) and on the inner bottom of the top mounting bracket (600). An electric clamp (12) is installed on the front side wall of the lead screw slider of the lead screw transmission mechanism (1). The electric clamp (12) holds a carbon-carbon composite workpiece (13). The processing mechanism (200) includes an outer processing frame (201), an inner processing frame (202), two connectors (203) and four connecting cylinders (204). The four connecting cylinders (204) are bolted to the outer processing frame. At the midpoint between the top and bottom of the two side walls of the frame (201), two connectors (203) are fixedly connected to the center of the upper and lower side walls of the inner processing frame (202), respectively. Each connector (203) is used in conjunction with four connecting cylinders (204). Elastic scrubbing material (206) is connected to both the inner side wall of the outer processing frame (201) and the outer side wall of the inner processing frame (202). A base coat spray nozzle (205) is installed on the inner side of both side walls of the outer processing frame (201) and the outer side of both side walls of the inner processing frame (202), above the elastic scrubbing material (206). Cleaning nozzles (207) are installed on the bottom side of the inner side of both sides of the work frame (201) and on the bottom side of both sides of the inner processing frame (202). Trigger switches (208) are installed on the bottom side of the notch of the outer processing frame (201) and on the bottom side of the elastic scrubbing material (206), as well as on the bottom side of the rear side wall of the inner processing frame (202) and on the bottom side of the elastic scrubbing material (206). Several trigger switches (208) located above are electrically connected to the base material nozzle (205), and several trigger switches (208) located below are electrically connected to the cleaning nozzles (207).

2. The method for preparing a silicon carbide coating for carbon-carbon composite materials according to claim 1, wherein the top mounting frame (600) includes a main frame (601), a rack and pinion connecting frame (602), and a toothed bevel connecting frame (603).

3. The method for preparing a silicon carbide coating for carbon-carbon composite materials according to claim 2, wherein the rack and pinion connector (602) is fixedly connected to one side of the rear end face of the front side wall of the main frame (601), and the toothed bevel connector (603) is fixedly connected to the middle of the rear end face of the front side wall of the main frame (601).

4. The method for preparing a silicon carbide coating for carbon-carbon composite materials according to claim 3, wherein a composite rack (5) is slidably connected inside the rack connecting frame (602), one side wall of the composite rack (5) is provided with a straight rack, the other side wall of the composite rack (5) is provided with a helical rack, the straight rack portion of one side wall of the composite rack (5) meshes with the rotating gear (4) at the processing end, and a transmission is installed on one side wall of the bevel connecting frame (603) near the top position via a bearing. A toothed cone (9) is mounted on the front side wall of the main frame (601) near the top of the rear end face via a bearing. The transmission toothed cone (9) meshes with the transmission toothed cone (11). The transmission toothed cone (11) meshes with the helical rack portion of the composite rack (5). A transmission helical rack (10) is slidably connected to the front side wall of the main frame (601) below the transmission toothed cone (9). The front half of the transmission helical rack (10) meshes with the transmission toothed cone (9).

5. The method for preparing a silicon carbide coating for carbon-carbon composite materials according to claim 4, wherein the workpiece rotating mechanism (800) includes a suspension (801), a top motor (802), an active toothed bevel (803), a turntable (804), a telescopic rod (805), and a contact head (806); The suspension (801) is fixedly connected to the top position on the other side of the rear end face of the front side wall of the main frame (601). The top motor (802) is bolted to the upper side wall of the suspension (801) away from the main frame (601). The active toothed cone (803) is located below the suspension (801) and connected to the movable end of the top motor (802). The rear half of the transmission helical rack (10) of the active toothed cone (803) is engaged. The turntable (804) is fixedly connected to the lower side of the active toothed cone (803). The telescopic rod (805) is embedded in the lower side wall of the turntable (804). The contact head (806) is rotatably connected to the movable end of the telescopic rod (805).

6. The method for preparing a silicon carbide coating for carbon-carbon composite materials according to claim 5, characterized in that: The method for preparing the silicon carbide coating for the carbon-carbon composite material includes the following steps: S1. Move the electric slider of the lead screw drive mechanism (1) to the bottom, then clamp the carbon-carbon composite workpiece (13) in the electric clamp (12), start the lead screw drive mechanism (1), and the electric clamp (12) drives the carbon-carbon composite workpiece (13) to rise into the processing mechanism (200). At this time, the movable ends of the two connecting cylinders (204) at the top drive the locking blocks to lock in the connecting head (203) at the top. S2. When the two sides and the front part of the electric clamp (12) first contact the trigger switches (208) located at the bottom, the cleaning nozzle (207) starts to work and cleans a part of the carbon-carbon composite workpiece (13). When the part of the carbon-carbon composite workpiece (13) moves to the middle of the two elastic scrubbing materials (206), the two elastic scrubbing materials (206) are squeezed and deformed and come into contact with the carbon-carbon composite workpiece (13), and remove the adhering carbon-carbon composite material. Wipe the moisture off the inner and outer surfaces of the carbon composite workpiece (13). When the two sides of the electric clamp (12) and the front part of the electric clamp (12) first contact with the trigger switches (208) on the top, the primer spray nozzle (205) starts to work, spraying primer onto the inner and outer surfaces of the carbon composite workpiece (13). Two elastic scrubbing materials (206) block the upper and lower cavities inside the processing mechanism (200) to prevent the airflow and water flow in the lower cavity from affecting the workpiece spraying operation in the upper cavity. S3. When the two sides of the electric clamp (12) and the front part of the electric clamp (12) come into contact with the trigger switches (208) at the bottom again, the cleaning nozzle (207) stops working, the workpiece is cleaned, and the movable ends of the two connecting cylinders (204) at the top retract, and the movable ends of the two connecting cylinders (204) at the bottom drive the locking block to lock in the connector (203) at the bottom. Then the workpiece continues to rise until the two sides of the electric clamp (12) and the front part of the electric clamp (12) come into contact with the trigger switches (208) at the top again. At this time, the primer spray nozzle (205) stops working, and the workpiece completes the cleaning and primer spraying of the inner and outer parts of both sides. S4. After the workpiece has been cleaned and the base material has been sprayed on the inner and outer sides, the screw drive mechanism (1) will drive the workpiece to continue to rise to the top drying box (7) to dry the base material sprayed on the workpiece. After drying, the screw drive mechanism (1) will drive the workpiece to continue to rise to the top of the top mounting bracket (600). S5. When the lead screw drive mechanism (1) drives the carbon-carbon composite workpiece (13) to rise to the top position of the top mounting bracket (600), the electric clamp (12) loosens, and then the telescopic rod (805) drives the contact head (806) to extend and press the contact head (806) against the front side wall of the carbon-carbon composite workpiece (13). Then the top motor (802) drives the turntable (804) to rotate, thereby rotating the carbon-carbon composite workpiece (13) by ninety degrees. After the rotation is completed, the electric clamp (12) clamps the material again. S6. When the turntable (804) rotates, the active tooth cone (803) fixedly connected to the top of the turntable (804) rotates accordingly. The active tooth cone (803) drives the transmission helical rack (10) meshing with it to move, thereby driving the transmission tooth cone (9) and the linkage tooth cone (11) meshing with the transmission tooth cone (9) to rotate. Under the drive of the linkage tooth cone (11), the composite rack (5) is raised and lowered. When the composite rack (5) is raised and lowered, the straight tooth part of the composite rack (5) drives the processing end rotating gear (4) to rotate, thereby rotating the processing mechanism (200) by 180 degrees, causing the cleaning nozzle (207) of the processing mechanism (200) to face upward and the base material nozzle (205) to face downward. S7. After the machining mechanism (200) has finished turning and the carbon-carbon composite workpiece (13) has rotated 90 degrees, the screw drive... The structure (1) drives the carbon-carbon composite workpiece (13) downward and repeats steps S2 and S3 until the inner and outer surfaces of the carbon-carbon composite workpiece (13) are cleaned, dried and coated with primer. S8. After the inner and outer surfaces of the carbon-carbon composite workpiece (13) have been cleaned, dried and coated with base material, the screw drive mechanism (1) drives the carbon-carbon composite workpiece (13) to the drying box (7) at the bottom for secondary drying. S9. After drying, remove the carbon-carbon composite workpiece (13) from the electric clamp (12), and then place the carbon-carbon composite workpiece (13) into the magnetization furnace for ceramic treatment, so that a silicon carbide coating can be obtained on the surface of the carbon-carbon composite workpiece (13).

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