Carbon-carbon composite material defect repairing liquid, preparation method thereof and defect repairing method of carbon-carbon composite material component

Abstract

The application provides a carbon-carbon composite material defect repairing liquid, a preparation method thereof and a defect repairing method of a carbon-carbon composite material component, and the carbon-carbon composite material defect repairing liquid comprises the following components in percentage by mass: 0.05%-0.2% of a silane coupling agent, 5%-14% of an organic solvent, 10%-25% of graphite powder, 60%-80% of phenolic resin and 0.5%-2% of polyvinylpyrrolidone, wherein the mesh number of the graphite powder is 200-1000, the solid content of the phenolic resin is 80wt%-85wt%, and the residual carbon content of the phenolic resin is 60wt%-75wt%. The carbon-carbon composite material defect repairing liquid has a good defect repairing effect on the carbon-carbon composite material component, and has the advantages of simple operation, short cycle and low cost.

Description

Technical Field

[0001] This application relates to the field of composite material technology, and in particular to a carbon-carbon composite defect repair liquid and its preparation method, and a method for repairing defects in carbon-carbon composite components. Background Technology

[0002] Carbon-carbon composite materials possess advantages such as low density, high strength, oxidation resistance, and high temperature resistance. In recent years, with the continuous deepening of related research, carbon-carbon composite materials have gradually expanded from military and aerospace applications to civilian industrial fields, such as photovoltaics, automobile manufacturing, and medical applications, and their demand is steadily increasing.

[0003] During the manufacturing process of carbon-carbon composite panels, structural defects such as pits, scratches, cracks, and delamination may occur due to improper handling. These defects affect the performance of the panels and require repair. Because carbon-carbon composite panels have certain purity requirements, conventional repair methods may introduce metallic impurities, further impacting their performance.

[0004] Currently, the main repair techniques for carbon-carbon composite panels are patching and impregnation repair. Patching involves removing the defective area, covering it with carbon fiber cloth or filaments, and then re-curing it with adhesive. Impregnation repair uses specialized equipment to place the panel into an impregnation tank, inject adhesive, and then cure it. Both methods require specialized equipment or a high level of technical skill, are complex to operate, have long processing times, and are costly, thus having limitations. Summary of the Invention

[0005] Based on this, this application provides a carbon-carbon composite defect repair liquid and its preparation method, as well as a method for repairing defects in carbon-carbon composite components. The carbon-carbon composite defect repair liquid has a good effect on repairing defects in carbon-carbon composite components, and is simple to operate, has a short cycle, and low cost.

[0006] The technical solution proposed in this application is as follows:

[0007] According to a first aspect of this application, a carbon-carbon composite material defect repair liquid is provided, comprising the following components by mass percentage:

[0008] Silane coupling agent 0.05%~0.2%;

[0009] Organic solvents 5%~14%;

[0010] Graphite powder 10%~25%;

[0011] Phenolic resin 60%~80%;

[0012] Polyvinylpyrrolidone 0.5%~2%;

[0013] The graphite powder has a mesh size of 200-1000 mesh; the phenolic resin has a solid content of 80wt%-85wt% and a residual carbon content of 60wt%-75wt%.

[0014] In some embodiments, the following components are included by weight percentage:

[0015] Silane coupling agent 0.05%~0.2%;

[0016] Organic solvents 5%~14%;

[0017] Graphite powder 18%~22%;

[0018] Phenolic resin 65%~75%;

[0019] Polyvinylpyrrolidone 0.5%~2%.

[0020] In some embodiments, the graphite powder has a mesh size of 500 to 1000 mesh.

[0021] In some embodiments, the phenolic resin is PF9501B phenolic resin.

[0022] In some embodiments, the silane coupling agent includes one or more of KH560, KH550, and KH570.

[0023] In some embodiments, the organic solvent includes one or more of ethanol, polyoxyethylene ether, polyvinylpyrrolidone, and N-methylpyrrolidone.

[0024] In some embodiments, the viscosity of the carbon-carbon composite defect repair fluid at 30°C is 500 mPa·s to 1000 mPa·s.

[0025] The polyvinylpyrrolidone used can be exemplified as polyvinylpyrrolidone K30 (abbreviated as: PVP K-30): CAS No. 9003-39-8, molecular weight approximately 40,000.

[0026] According to a second aspect of this application, a method for preparing the above-mentioned carbon-carbon composite defect repair liquid is provided, comprising the following steps:

[0027] The silane coupling agent, the organic solvent, the phenolic resin, and the polyvinylpyrrolidone are mixed according to a mass percentage to obtain a mixture.

[0028] The graphite powder is added to the mixture under stirring and ultrasonically dispersed to obtain the carbon-carbon composite defect repair liquid.

[0029] According to a third aspect of this application, a method for repairing defects in carbon-carbon composite components is provided, comprising the following steps:

[0030] Grind and clean the defective areas of the carbon-carbon composite component;

[0031] The carbon-carbon composite defect repair liquid of the first aspect of this application is applied to the defect area, compacted, and the carbon-carbon composite defect repair liquid is impregnated into the carbon-carbon composite component.

[0032] The carbon-carbon composite material component is baked, and the defective area is heated by flame.

[0033] In some embodiments, the baking temperature is 150℃~200℃ and the time is 4h~8h; the flame heating time is 10s~15s and the flame temperature is 1300℃~1800℃; after the compaction step and before the baking step, the carbon-carbon composite component is left to stand for 1.5h~2.5h to allow the carbon-carbon composite defect repair liquid to penetrate the carbon-carbon composite component.

[0034] Compared with traditional technologies, this application has at least the following beneficial effects:

[0035] The carbon-carbon composite defect repair liquid of this application is formulated by compounding graphite powder of a specific mesh size, phenolic resin with a specific solid content and residual carbon amount, polyvinylpyrrolidone, silane coupling agent, and organic solvent in a specific percentage. The specific mesh size of graphite powder has good compatibility with carbon fibers, allowing it to adhere to the surface of the carbon fibers at the defect site and fill the pores between the carbon fibers. The phenolic resin with the specific solid content and residual carbon amount acts as a binder, enhancing the adhesion between the graphite powder, carbon fibers, and the matrix material. Furthermore, the carbon formed after the carbonization and pyrolysis of the phenolic resin can form covalent bonds with the carbon in the carbon fibers and matrix material, further enhancing the bonding force between the graphite powder, carbon fibers, and matrix material. The polyvinylpyrrolidone, silane coupling agent, and organic solvent improve the dispersion uniformity of the graphite powder and give the repair liquid a suitable viscosity, reducing graphite powder agglomeration and allowing the graphite powder to adhere uniformly to the carbon fibers. This repair liquid can effectively repair defects in carbon-carbon composite components and is simple to operate, has a short repair cycle, and low cost. Detailed Implementation

[0036] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be independently included or excluded, and they can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this document; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, stating that a parameter is an integer ≥2 is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, stating that a parameter is an integer selected from "2~10" is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0038] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0041] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0042] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0043] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0044] Currently, the main repair techniques for carbon-carbon composite panels are patching and impregnation repair. Both of these methods either require specialized equipment or a high level of technical skill; and they also have limitations such as complex operation, long cycle time, and high cost.

[0045] For example, the patching method requires a high level of technical skill, as it involves laying carbon fiber cloth and carbon fiber filaments during the repair process. When laying the carbon fiber cloth and filaments, the texture must be consistent with or similar to the original carbon-carbon composite material; otherwise, color differences and uneven textures may occur. The impregnation repair method generally requires preparing a solution in an impregnation tank, immersing the carbon-carbon composite component to be repaired in it for impregnation and densification. Its verification time is long, generally requiring carbonization before observing whether the defective area has been repaired, which takes 7 to 10 days. If the repair fails, the repair process needs to be repeated, further extending the repair cycle.

[0046] In response, one embodiment of this application provides a carbon-carbon composite material defect repair liquid, which comprises the following components by mass percentage:

[0047] Silane coupling agent 0.05%~0.2%;

[0048] Organic solvents 5%~14%;

[0049] Graphite powder 10%~25%;

[0050] Phenolic resin 60%~80%;

[0051] Polyvinylpyrrolidone 0.5%~2%;

[0052] The graphite powder has a mesh size of 200-1000 mesh; the solid content of the phenolic resin is 80wt%-85wt%; and the residual carbon content of the phenolic resin is 60wt%-75wt%.

[0053] The aforementioned carbon-carbon composite defect repair liquid is formed by compounding graphite powder of a specific mesh size, phenolic resin with a specific solid content and residual carbon content, polyvinylpyrrolidone, silane coupling agent, and organic solvent in a specific percentage. The graphite powder of the specific mesh size has good compatibility with carbon fibers and can adhere to the surface of the carbon fibers at the defects in the carbon-carbon composite component, filling the pores between the carbon fibers. The phenolic resin with the specific solid content and residual carbon content acts as a binder, enhancing the adhesion between the graphite powder, carbon fibers, and the matrix material. Furthermore, the carbon formed after the carbonization and pyrolysis of the phenolic resin can form covalent bonds with the carbon in the carbon fibers and the matrix material, further enhancing the bonding force between the graphite powder, carbon fibers, and the matrix material. The polyvinylpyrrolidone, silane coupling agent, and organic solvent can improve the dispersion uniformity of the graphite powder and give the repair liquid a suitable viscosity, reducing graphite powder agglomeration and allowing the graphite powder to adhere uniformly to the carbon fibers.

[0054] The fineness of graphite powder affects its dispersion uniformity in the repair solution and the ease of adsorption, thus influencing the repair effect. The solid content and residual carbon content of the phenolic resin directly affect the bonding hardness and overall stability of the repaired area, while also affecting the viscosity of the repair solution and the dispersion performance of the graphite powder. Both the graphite powder and phenolic resin content affect the structural strength of the repaired area. Through the synergistic interaction of the components in the repair solution, this carbon-carbon composite defect repair solution can effectively repair defective areas of carbon-carbon composite components, reducing the likelihood of cracking in the repaired areas. Furthermore, it requires no specialized equipment, has low technical skill requirements for construction personnel, is simple to operate, has a short repair cycle, and is low in cost.

[0055] In this application, carbon-carbon composite material refers to a high-performance composite material with carbon fiber as the reinforcing material and deposited carbon as the matrix material. Carbon-carbon composite component is a structural part of various structures or shapes made of carbon-carbon composite material, such as carbon-carbon composite sheet. Surface defects of carbon-carbon composite component include surface scratches, cracks, localized delamination between layers, and small-scale pits. The mesh size of the graphite powder can be determined according to GB / T 19077.1-2003.

[0056] Understandably, the mesh size of the graphite powder can be 200 mesh, 250 mesh, 300 mesh, 350 mesh, 400 mesh, 450 mesh, 500 mesh, 550 mesh, 600 mesh, 650 mesh, 700 mesh, 750 mesh, 800 mesh, 850 mesh, 900 mesh, 950 mesh, 1000 mesh, or any value within the range formed by any two of the above values; the solid content of the phenolic resin can be 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, or any value within the range formed by any two of the above values; the residual carbon content of the phenolic resin can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, or any value within the range formed by any two of the above values.

[0057] In some embodiments, the carbon-carbon composite defect repair fluid comprises the following components by mass percentage:

[0058] Silane coupling agent 0.05%~0.2%;

[0059] Organic solvents 5%~14%;

[0060] Graphite powder 18%~22%;

[0061] Phenolic resin 65%~75%;

[0062] Polyvinylpyrrolidone 0.5%~2%.

[0063] Thus, by further controlling the graphite powder content in the carbon-carbon composite defect repair liquid to 18%~22% and the phenolic resin content to 65%~75%, it is more conducive to improving the repair effect on carbon-carbon composite defects. The repaired part is less likely to crack and does not require rework.

[0064] In some embodiments, the graphite powder has a mesh size of 500 to 1000 mesh. Further controlling the mesh size of the graphite powder within this range is more conducive to improving the uniformity of graphite powder dispersion in the repair fluid, allowing the graphite powder to adhere more evenly to the carbon fiber surface at the defect location, filling the pores between the carbon fibers, thereby further improving the repair effect.

[0065] Furthermore, the volume average particle size (Dv50) of the graphite powder is 10 μm to 15 μm. Graphite powder with these particle sizes exhibits good blendability and compatibility with the carbon fiber matrix, which is beneficial for improving the defect repair effect.

[0066] Here, Dv50 has a well-known meaning in the art and can be tested using methods known in the art. For example, it can be measured using a laser particle size analyzer (such as the Malvern Master Size 3000). Dv50 represents the particle size at which the percentage of particle volume distribution accumulates to 50% based on the particle size distribution, starting from the smallest particle size.

[0067] Particle size distribution can be obtained by the following method: Take a clean beaker, add an appropriate amount of the sample to be tested, and sonicate thoroughly to ensure complete dispersion. The testing instrument is a Malvern 2000 (USA). After the sample is poured into the injection tower, it circulates with the solution to the test optical path system. Under the illumination of the laser beam, the particle size distribution characteristics can be obtained by receiving and measuring the energy distribution of the scattered light (opause level: 8%~12%). Particle size distribution diagrams are plotted based on the test data.

[0068] In some embodiments, the phenolic resin includes PF9501B phenolic resin manufactured by Shengquan Company. The aforementioned phenolic resin has a high solids content and residual carbon content, which is beneficial for achieving better repair results at the repair site.

[0069] In some embodiments, the silane coupling agent includes one or more of KH560, KH550, and KH570. Using the above-mentioned silane coupling agent, in combination with polyvinylpyrrolidone and organic solvents, is beneficial for improving the interfacial compatibility between the components of the repair solution, improving the dispersion uniformity of graphite powder, reducing graphite powder agglomeration, and enabling the graphite powder to adhere more uniformly to the carbon fiber.

[0070] In some embodiments, the organic solvent includes one or more of ethanol, polyoxyethylene ether, polyvinylpyrrolidone, and N-methylpyrrolidone. This facilitates the uniform dispersion of the components in the repair solution.

[0071] In some embodiments, the viscosity of the carbon-carbon composite defect repair fluid at 30°C is 500 mPa·s to 1000 mPa·s. Thus, by compounding the components at specific concentrations, the repair fluid achieves a suitable viscosity, which is beneficial for ensuring high bonding hardness and good overall stability at the repaired site, resulting in a better defect repair effect.

[0072] One embodiment of this application provides a method for preparing the above-mentioned carbon-carbon composite material defect repair liquid, the preparation method comprising the following steps S10 and S20:

[0073] Step S10: Mix the silane coupling agent, organic solvent, phenolic resin and polyvinylpyrrolidone by mass percentage to obtain a mixture.

[0074] Step S20: Add graphite powder to the mixture under stirring, and disperse it by ultrasonication to obtain a carbon-carbon composite material defect repair liquid.

[0075] Therefore, by first mixing the silane coupling agent, organic solvent, phenolic resin, and polyvinylpyrrolidone, and then adding graphite powder to the mixture under stirring, the uniformity of graphite powder dispersion can be improved. Alternatively, the graphite powder can be added to the mixture in batches while stirring. That is, a portion of the graphite powder is added first, and mechanical stirring is used to form a homogeneous medium; then another portion of graphite powder is added, and this process is repeated until all the graphite powder is added; finally, ultrasonic dispersion is performed to obtain a carbon-carbon composite defect repair solution.

[0076] In this application, the ultrasonic dispersion time can be 10 min to 30 min. It can also be 20 min.

[0077] One embodiment of this application provides a method for repairing defects in carbon-carbon composite components, including the following steps S100 to S300:

[0078] Step S100: Grind and clean the defective areas of the carbon-carbon composite component.

[0079] Step S200: Apply the carbon-carbon composite defect repair liquid described above to the defect area, compact it, and allow the carbon-carbon composite defect repair liquid to penetrate into the carbon-carbon composite component.

[0080] Step S300: Bake the carbon-carbon composite component and heat the defective area with a flame.

[0081] The above-mentioned defect repair method for carbon-carbon composite components uses the carbon-carbon composite defect repair liquid of this application to repair the defective areas of the carbon-carbon composite components. After processes such as compaction, impregnation, baking and flame heating, the defective areas of the carbon-carbon composite components can be effectively repaired. It not only has a good repair effect, but also does not require professional equipment, has low technical proficiency requirements, is simple to operate, has a short repair cycle, and low cost.

[0082] Specifically, the defect areas and conditions of carbon-carbon composite components are first determined through non-destructive testing (such as tapping the delamination area, measuring the depth of pits with a depth gauge, measuring the depth of cracks and scratches, ultrasonic testing, etc.). Generally, defects with a pit depth of no more than 3 mm, a pit diameter of no more than 2 mm, and a delamination area of ​​no more than 50 mm × 50 mm can be repaired.

[0083] Then, Teflon cloth is laid on the surface of the horizontal platform. The defective carbon-carbon composite component is placed on the Teflon cloth. First, the defective area is smoothed using sandpaper or other tools. Then, carbon residue and ash in the smoothed area are cleaned using an air gun. The carbon-carbon composite defect repair liquid of this application is transferred to the defective area using a syringe until it is completely wetted. The internal penetration is checked. Another layer of Teflon cloth is then placed on the surface of the defective area. The defective area is compacted using tooling fixtures or graphite plates. The criterion for judging complete internal penetration is: after the liquid drips onto the solid surface, it spontaneously expands to completely cover it, and the perimeter continues to move until it is flat; subsequent drips of liquid continue to spread to the surrounding area.

[0084] After the repair fluid has fully impregnated the component, transfer the carbon-carbon composite component and tooling fixtures or graphite plates to an oven for baking, setting the baking temperature and time. After baking, transfer the carbon-carbon composite component to a platform and heat the defective area using a cartridge-type blowtorch. After cooling, perform non-destructive testing. If defects still exist, repeat the steps of applying repair fluid, compaction, baking, and blowtorch heating; if the defects are gone, the repair is complete.

[0085] In some embodiments, the baking temperature can be 150°C to 200°C, and the baking time can be 4 hours to 8 hours. More optionally, the baking temperature is 180°C, and the baking time is 4 hours. The flame heating time can be 10 seconds to 15 seconds; the flame temperature is 1300°C to 1800°C. Heating is performed using the outer flame region, with the flame tip approximately 1 cm away from the workpiece.

[0086] In some embodiments, after the compaction step and before the baking step, the carbon-carbon composite component is left to stand for 1.5 to 2.5 hours to allow the carbon-carbon composite defect repair liquid to fully penetrate the carbon-carbon composite component. Optionally, the standing time is 2 hours.

[0087] The present application will be further described below with reference to specific embodiments and comparative examples, but should not be construed as limiting the scope of protection of the present application.

[0088] Example 1:

[0089] Non-destructive testing was used to determine the defective areas and conditions of the carbon-carbon composite sheet. Teflon cloth was laid on a horizontal platform, and the defective carbon-carbon composite sheet was placed on top of the cloth. The defective area was smoothed with sandpaper, and then the carbon residue and ash in the sanded area were cleaned with a compressed air gun. A carbon-carbon composite defect repair fluid was transferred to the defective area using a syringe. After the repair fluid had fully saturated the area, another layer of Teflon cloth was placed over the defective area, and the defective area was compacted using a graphite plate.

[0090] After the repair fluid has fully impregnated the surface for 2 hours, transfer the carbon-carbon composite material sheet and graphite plate together to an oven and bake at 180°C for 4 hours. After baking, transfer the carbon-carbon composite material sheet to a platform and heat the defective area with a cartridge torch for 12 seconds. After cooling, perform non-destructive testing. If defects still exist after testing, rework is performed (i.e., repeating the steps of applying repair fluid, compaction, baking, and torching) until no defects are found; when no defects are found, the repair is complete.

[0091] The component formulation of the carbon-carbon composite defect repair liquid used in this embodiment is shown in Table 1.

[0092] Examples 2-6:

[0093] The defect repair methods in Examples 2-6 are basically the same as those in Example 1, except that the component formulations of the carbon-carbon composite defect repair fluid used are different. The component formulations of the carbon-carbon composite defect repair fluid used in Examples 2-6 are shown in Table 1.

[0094] Comparative Examples 1-2:

[0095] The defect repair methods in Comparative Examples 1 and 2 are basically the same as those in Example 1, except that the component formulations of the carbon-carbon composite defect repair fluid used are different. The component formulations of the carbon-carbon composite defect repair fluids used in Comparative Examples 1 and 2 are shown in Table 1.

[0096] Test method:

[0097] (1) Judgment of repair effect

[0098] Based on the repair results of the repaired areas, they are categorized from best to worst as "Excellent", "Good", "Requires Rework" and "Unsatisfactory".

[0099] Specifically, (a) if no defects appear after a single repair and the tensile strength of the repaired material is greater than 80%, the repair effect is judged as "excellent"; (b) if no defects appear after a single repair and the tensile strength (relative to the tensile strength recovery rate under undamaged conditions) of the repaired material is 70%~80%, the repair effect is judged as "good"; (c) if defects still appear after a single repair but are eliminated after rework and the tensile strength of the material is greater than or equal to 70%, the repair effect is judged as "rework required"; (d) if the tensile strength of the material is lower than 70% after repair to eliminate defects, the repair effect is judged as "unqualified".

[0100] The composition ratios and defect repair effects of the carbon-carbon composite defect repair liquids in the above embodiments and comparative examples are shown in Table 1. The solid content of phenolic resin PF9501B is 82.5 wt%, and the residual carbon content is 75 wt%; the solid content of phenolic resin PF9701 is 58 wt%, and the residual carbon content is 55 wt%. " / " in Table 1 indicates that the substance is not present.

[0101] Table 1

[0102]

[0103] As shown in Table 1, the carbon-carbon composite material defect repair liquid used in the various embodiments of this application can effectively repair the defective parts of the carbon-carbon composite material plates, and the repaired material has high strength. Among them, in Examples 2 and 5, the mass content of phenolic resin and graphite powder is within the preferred range, and their repair effect on the defective parts is better than that in Examples 1, 3-4 and 6, and no rework is required.

[0104] Compared with Example 4, Comparative Example 1 differed from Comparative Example 4, and Comparative Example 2 differed from Example 5, except that PF9701, a phenolic resin with low solid content and low residual carbon content, was used instead of PF9501B, a phenolic resin with high solid content and high residual carbon content. The repaired carbon-carbon composite material sheets showed obvious cracking at the defective areas, low tensile strength, and the repair effect was unsatisfactory.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for repairing defects in carbon-carbon composite components, characterized in that, Includes the following steps: Grind and clean the defective areas of the carbon-carbon composite component; The carbon-carbon composite defect repair liquid is applied to the defect area, compacted, and allowed to penetrate the carbon-carbon composite component. The carbon-carbon composite material component is baked, and the defective area is heated by jet flame. The carbon-carbon composite defect repair fluid comprises the following components by mass percentage: Silane coupling agent 0.05%~0.2%; Organic solvents 5%~14%; Graphite powder 18%~22%; Phenolic resin 65%~75%; Polyvinylpyrrolidone 0.5%~2%; The graphite powder has a mesh size of 500-1000 mesh; the phenolic resin has a solid content of 80wt%-85wt% and a residual carbon content of 60wt%-75wt%; the volume average particle size (Dv50) of the graphite powder is 10μm-15μm; the phenolic resin is PF9501B phenolic resin; and the carbon-carbon composite defect repair liquid has a viscosity of 500mPa·s-1000mPa·s at 30℃.

2. The defect repair method for carbon-carbon composite components according to claim 1, characterized in that, The silane coupling agent includes one or more of KH560, KH550 and KH570.

3. The method for repairing defects in carbon-carbon composite components according to claim 1 or 2, characterized in that, The organic solvent includes one or more of ethanol, polyoxyethylene ether, polyvinylpyrrolidone, and N-methylpyrrolidone.

4. The defect repair method for carbon-carbon composite components according to claim 1 or 2, characterized in that, The preparation method of the carbon-carbon composite defect repair fluid includes the following steps: The silane coupling agent, the organic solvent, the phenolic resin, and the polyvinylpyrrolidone are mixed according to a mass percentage to obtain a mixture. The graphite powder is added to the mixture under stirring and ultrasonically dispersed to obtain the carbon-carbon composite defect repair liquid.

5. The method for repairing defects in carbon-carbon composite components according to claim 1 or 2, characterized in that, The baking temperature is 150℃~200℃, and the time is 4h~8h.

6. The defect repair method for carbon-carbon composite components according to claim 1 or 2, characterized in that, The heating time is 10s~15s, and the flame temperature is 1300℃~1800℃.

7. The method for repairing defects in carbon-carbon composite components according to claim 1 or 2, characterized in that, After the compaction step and before the baking step, the carbon-carbon composite component is left to stand for 1.5h to 2.5h to allow the carbon-carbon composite defect repair liquid to penetrate the carbon-carbon composite component.

Images