Method for improving component uniformity of surface coating of curved-surface C / C composite material

Abstract

The invention discloses a method for improving component uniformity of a surface coating of a curved-surface C / C composite material, which comprises the following steps: preparing a single-phase / multi-phase ceramic coating on the surface of the curved-surface C / C composite material to obtain a test piece; a resin carbon barrier layer is prepared on the surface of a test piece, then the test piece is subjected to siliconizing treatment, and the method can improve the phenomenon that components of a coating in the corner area of the curved surface C / C composite material are not uniform.

Description

Technical Field

[0001] The invention belongs to a method for improving the uniformity of the coating composition on the surface of a curved C / C composite material. Background Art

[0002] Carbon / carbon (C / C) composites are a kind of pure carbon multiphase structure with carbon fiber or its fabric as the reinforcement phase, and pyrolytic carbon infiltrated by chemical vapor phase or resin carbon or asphalt carbon infiltrated by liquid phase carbonization as the matrix. C / C composites have excellent properties such as high specific strength, high specific modulus, low thermal expansion coefficient, and high temperature resistance. In particular, their mechanical properties increase instead of decrease at high temperatures, and even have a high mechanical property retention rate above 2000℃. They have broad application prospects in many high-temperature antioxidant and ablation-resistant materials. However, since C / C composites are all-carbon structures, when exposed to an oxygen atmosphere above 370℃, the carbon fiber and the matrix will oxidize rapidly. Severe oxidation will cause the mechanical properties of C / C composites to drop rapidly, greatly limiting their application in the aerospace field.

[0003] At present, the methods to improve the high-temperature oxidation and ablation resistance of C / C composites mainly include surface coating and matrix modification. Among them, high-temperature coating technology can completely isolate oxidizing gases from the matrix material, and can meet the needs of long-term oxidation protection of C / C composites. The main methods for preparing coatings include embedding, spraying, chemical vapor deposition, slurry coating, gas / liquid phase siliconization, etc. Among them, the slurry coating method is simple to operate, and the coating composition and structure can be designed, but the coating has many pores inside and has poor bonding with the substrate. At present, slurry coating is usually combined with gas / liquid phase siliconization, which has a short preparation cycle and can be used for coating preparation of curved and special-shaped components. However, the uniformity of the surface coating of curved parts is extremely difficult to control, which greatly affects its service life in the actual service environment.

[0004] In the document "Yuqi Wang, Lingxiang Guo, Yuyu Zhang, Xuemeng Zhang, Hongkang Ou, Jia Sun*. Ablation behaviors and mechanism of ZrC-SiC-Si / SiC-Si double-layered coatings on C / C composite under plasma flame at 3000℃. Corrosion Science, 2023, 218: 111200", a ZrC-SiC-Si / SiC-Si double-layer coating was prepared by slurry coating combined with vapor phase siliconization. However, the scouring effect of silicon vapor on the porous pre-coating at high temperature caused the loss of ultra-high temperature ceramic phase and coating thinning, and the coating uniformity was difficult to control.

[0005] In the second document "Ding Wuqing, Zhou Lei, Zhang Jiaping*, Fu Qiangang*. Long-term oxidation of MoSi2-modified HfB2-SiC-Si / SiC-Si coating at1700℃[J]. Surface Engineering, 2023, 39(3): 315-325", HfB2-SiC-Si / SiC-Si coating was successfully prepared by slurry coating combined with vapor phase siliconization method, but serious element segregation phenomenon occurred inside the coating and the coating composition was uneven.

[0006] Reference 3 "Li Tao, Zhang Yulei*, Lv Junshuai, Fu Yanqin, Sun Jia, Qiang Xinfa. A novel MoSi2-rich coating on the SiC-Si coated C / C composites for the preparation and antioxidative properties at 1773K and 1973K. Corrosion Science, 2022, 204: 110392" uses slurry brushing, high-temperature reaction sintering combined with liquid phase siliconization to obtain a MoSi2-rich coating with good inner and outer layer bonding and dense structure. However, only in the size of 10×10×10cm 3 The coating is prepared on the surface of standard oxidation samples, which cannot provide a strong theoretical support for the high-temperature oxidation protection of curved and special-shaped components. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for improving the uniformity of the coating composition on the surface of a curved C / C composite material, which can improve the phenomenon of uneven coating composition in the corner area of ​​the curved C / C composite material.

[0008] To achieve the above object, the present invention discloses a method for improving the uniformity of the coating composition on the surface of a curved C / C composite material, comprising the following steps:

[0009] A single-phase / multi-phase ceramic coating is prepared on the surface of a curved C / C composite material to obtain a test piece;

[0010] A resin carbon barrier layer is prepared on the surface of the specimen, and then the specimen is subjected to siliconization treatment.

[0011] Furthermore, the process of preparing a single-phase / multi-phase ceramic coating on the surface of the curved C / C composite material is as follows:

[0012] 11) Cleaning and drying the curved surface C / C composite material;

[0013] 12) dissolving resin 1 in anhydrous ethanol A to obtain resin solution A;

[0014] Dissolve resin 2 in anhydrous ethanol B to obtain resin solution B, add one or a mixture of ZrB2 or HfB2, SiC, HfSi2, MoSi2, ZrSi2 and TaSi2 to the resin solution B, stir and then disperse by ultrasonic to obtain a mixed slurry;

[0015] 13) The mixed slurry is applied to the surface of the curved C / C composite material, and then dried to obtain a ceramic coating.

[0016] Furthermore, the resin 1 is a mixture of one or more resins selected from the group consisting of phenolic resin, epoxy resin, polyester resin and furan resin.

[0017] Furthermore, the mass ratio of resin 1 to anhydrous ethanol A is 10-30:60-80.

[0018] Furthermore, the mass ratio of the resin 2, anhydrous ethanol, BZrB2 or HfB2, SiC and a mixture of one or more of HfSi2, MoSi2, ZrSi2 and TaSi2 is 5-20:70-90:20-40:40-60:5-20.

[0020] Furthermore, the process of preparing a resin carbon barrier layer on the surface of the specimen and then performing siliconizing treatment on the specimen is as follows:

[0021] 21) Coating the resin solution A on the corners of the specimen, and then drying it to obtain a resin carbon barrier layer;

[0022] 22) The test piece obtained in step 21) is cured at 150-200° C., and then carbonized in an argon atmosphere at 900-1200° C. to obtain a ceramic pre-coating with a resin carbon barrier layer at the corners.

[0023] 23) preparing mixed powder;

[0024] 24) The test piece obtained in step 22) is placed in a graphite crucible with a 5-10 mm thick mixed powder on the bottom, and then the mixed powder is added to the graphite crucible until the mixed powder covers the test piece by 5-10 mm. The graphite crucible is then sealed, and then the temperature is raised to 1500-1700°C at a rate of 4-10°C / min under vacuum conditions, and then cooled after being kept warm.

[0025] Further, the operation process of step 23) is:

[0026] Si powder, SiC and C powder are mixed, ball-milled and then dried to obtain a mixed powder.

[0027] Furthermore, the mass ratio of Si powder, SiC and C powder is 50-80:5-25:10-25.

[0028] The curved surface C / C composite material surface coating of the present invention is prepared based on the method for improving the uniformity of the composition of the curved surface C / C composite material surface coating.

[0029] The present invention has the following beneficial effects:

[0030] The method for improving the uniformity of the coating composition of the surface of the C / C composite material on a curved surface described in the present invention is to construct a resin carbon barrier layer, and after applying the ceramic outer coating, directly apply the resin solution on the corners of the curved surface sample, and obtain a pre-coating layer with resin carbon through carbonization treatment. The operation is simple and convenient, and the preparation time of the traditional repeated coating method is greatly reduced. In addition, the resin carbon barrier layer can effectively alleviate the erosion of the porous pre-coating layer by the melt flow during the siliconization process, reduce the loss of ultra-high temperature ceramic phases in local areas, improve the uniformity of the overall coating composition, and make the coating have stable high-temperature antioxidant properties, thereby avoiding the local coating from failing first due to uneven coating. The present invention can further provide a solution to the local damage to the substrate caused by the melt infiltration process, and obtain the protection effect that both the substrate and the coating can be protected from melt erosion.

[0031] Furthermore, by adjusting the content of each component in the original slurry, the ceramic outer coating and the resin carbon layer can be applied in different areas to achieve a controllable structural design of a uniform coating on the surface of the curved sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 It is a process flow chart of the present invention.

[0034] Figure 2 The cross-sectional SEM and energy spectrum of the carbonized coating sample with pre-coating in different regions, where: Figure 2Among them, (a) is a cross-sectional SEM image of the sample coated with 50wt.% HfB2 at the corner area after carbonization; (b) is a cross-sectional SEM image and point scan energy spectrum image of the sample coated with 50wt.% HfB2 at the corner area after carbonization; (c) is a cross-sectional SEM image of the sample coated with 60wt.% HfB2 at the corner area after carbonization; (d) is a cross-sectional SEM image and point scan energy spectrum image of the sample coated with 60wt.% HfB2 at the corner area after carbonization.

[0035] Figure 3 To construct the cross-sectional SEM and energy spectrum of the coating sample after carbonization, Figure 3 Among them, (a) is a cross-sectional SEM image of the sample coated with 40wt.% HfB2 and resin carbon at the corners after carbonization; (b) is a cross-sectional SEM image of the sample coated with 50wt.% HfB2 and resin carbon at the corners after carbonization; (c) is a cross-sectional SEM image of the sample coated with 60wt.% HfB2 and resin carbon at the corners after carbonization; (d) is a high-magnification SEM image of the framed area in Figure (a); (e) is a high-magnification SEM image of the framed area in Figure (b); (f) is a high-magnification SEM image of the framed area in Figure (c); (g) is a surface scan energy spectrum image of Figure (d);

[0036] Figure 4 This is a cross-sectional SEM image of the coating sample after siliconization with a pre-coating layer and a resin carbon barrier layer in different regions. Figure 4 In the figure, (a) is the cross-sectional SEM image of the sample with 40wt.% HfB2 coated at the corners after siliconization; (b) is the cross-sectional SEM image of the sample with 50wt.% HfB2 coated at the corners after siliconization; (c) is the cross-sectional SEM image of the sample with 60wt.% HfB2 coated at the corners after siliconization; (d) is the cross-sectional SEM image of the sample with 40wt.% HfB2 and resin carbon coated at the corners after siliconization; (e) is the cross-sectional SEM image of the sample with 50wt.% HfB2 and resin carbon coated at the corners after siliconization; (f) is the cross-sectional SEM image of the sample with 60wt.% HfB2 and resin carbon coated at the corners after siliconization. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0039] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0040] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0041] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0042] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0045] The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to the present invention comprises:

[0046] 1) Preparation of single-phase / multi-phase ceramic coatings on the surface of curved C / C composites;

[0047] 11) The density of the embedded SiC inner coating is 1.7-1.8 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) is ultrasonically cleaned with deionized water for 4-6 times, each cleaning time is 20-40 minutes, and dried in an electric heating blast drying oven at a temperature of 60-100°C for 6-10 hours;

[0048] 12) dissolving 10-30 wt. % of a mixture of one or more of phenolic resin, epoxy resin, polyester resin and furan resin in 60-80 wt. % of anhydrous ethanol to obtain a resin solution A;

[0049] A mixture of 5 to 20 wt.% of one or more of phenolic resin, epoxy resin, polyester resin, and furan resin is fully dissolved in 70 to 90 wt.% of anhydrous ethanol to obtain a resin solution B;

[0050] Add one or more of ZrB2, HfB2, SiC, HfSi2, MoSi2, ZrSi2 and TaSi2 into the resin solution B in the ratio of 20-40wt.%, 40-60wt.%, and 5-20wt.%, stir thoroughly and place in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry to obtain a mixed slurry.

[0051] 13) Use a brush to apply the mixed slurry to the surface of the curved C / C composite material, and dry it in an electric heated air drying oven at a temperature of 60 to 100° C. for 10 to 20 minutes, and repeat the above brushing-drying steps until a ceramic coating of the desired thickness is obtained on the surface of the curved C / C composite material.

[0052] 2) preparing a resin carbon barrier layer on the surface of the test piece obtained in step 1);

[0053] 21) Coating the resin solution A on the corners of the test piece obtained in step 1) and drying it in an electric heated air drying oven at a temperature of 60 to 100° C. for 10 to 20 minutes to obtain a resin carbon barrier layer;

[0054] 22) Place the test piece obtained in step 21) into an Al2O3 ark and place it in a tubular heat treatment furnace, then cure it at 150-200°C for 1-2 hours, and then carbonize it in an argon atmosphere at 900-1200°C for 2-4 hours to obtain a ceramic pre-coating with a resin carbon barrier layer at the corners.

[0055] 23) 50-80wt.% Si powder, 5-25wt.% SiC and 10-25wt.% C powder are mixed and poured into a ball mill for 5-8h, and then placed in an electric heating blast drying oven at a temperature of 60-100°C for 10-16h to obtain a mixed powder;

[0056] 24) The test piece obtained in step 22) is placed in a graphite crucible with a 5-10 mm thick mixed powder on the bottom, and then the mixed powder is added to the graphite crucible until the mixed powder covers the test piece by 5-10 mm. The graphite crucible is then sealed and placed in a heat treatment furnace. The temperature is then raised to 1500-1700°C at a rate of 4-10°C / min under vacuum conditions, and the temperature is kept at this temperature for 1-2 hours. The power is then turned off and the temperature is lowered to obtain a PC-SiC-C / C curved surface sample modified with a ceramic coating.

[0057] Embodiment 1

[0058] This embodiment includes the following steps:

[0059] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 minutes, and dried in an electric heating blast drying oven at a temperature of 70°C for 8 hours;

[0060] 2) 23wt.% of phenolic resin is fully dissolved in 77wt.% of anhydrous ethanol to obtain phenolic resin solution A; 12wt.% of phenolic resin is fully dissolved in 88wt.% of anhydrous ethanol to obtain phenolic resin solution B, and then 40wt.% of SiC, 40wt.% of HfB2, and 20wt.% of MoSi2 are added to the phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry, and the HfB2-SiC-MoSi2-phenolic resin slurry is stirred and placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0061] 3) Use a brush to apply the HfB2-SiC-MoSi2-phenolic resin slurry to the surface of the curved PC-SiC-C / C sample and dry it in an electric blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0062] 4) Phenolic resin solution A was applied to the corners of the PC-SiC-C / C curved surface sample coated with the HfB2-SiC-MoSi2 external coating, and dried in an electric heated forced air drying oven at a temperature of 70°C for 20 minutes to obtain a resin carbon barrier layer.

[0063] 5) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating with a resin carbon barrier layer at the corners. Figure 3 (a, d, g) are cross-sectional SEM photos and energy spectra of the coating sample after carbonization to construct the resin carbon barrier layer. After carbonization, a resin carbon layer with a thickness of about 6 mm is formed on the outside of the ceramic coating in the corner area.

[0064] 6) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill, ball milled for 6 h, and then placed in an electric heated blast drying oven at a temperature of 70° C. for 12 h to obtain a mixed powder.

[0065] 7) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with resin carbon barrier layer at the corners with the convex surface facing up in a graphite crucible with a 6mm thick mixed powder on the bottom, and then continue to add mixed powder until the mixed powder covers the sample by 6mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600℃ at a rate of 10℃ / min under vacuum conditions, and keep it warm for 2h, then turn off the power and cool it down to obtain a PC-SiC-C / C curved surface sample modified with HfB2-SiC-MoSi2 coating.

[0066] The HfB2-SiC-MoSi2 coating obtained in this embodiment has a uniform coating composition in the corner area of ​​the PC-SiC-C / C curved surface sample, and there is no loss of ultra-high temperature ceramic phase. Figure 4 As shown in (d), it shows that the resin carbon as a barrier layer effectively alleviates the erosion of the coating at the corners of the sample by the melt.

[0067] Comparative Example 1

[0068] This comparative example comprises the following steps:

[0069] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0070] 2) 12 wt.% of phenolic resin is fully dissolved in 88 wt.% of anhydrous ethanol to obtain a phenolic resin solution, 40 wt.% of SiC, 40 wt.% of HfB2, and 20 wt.% of MoSi2 are added to the phenolic resin solution to obtain HfB2-SiC-MoSi2-phenolic resin slurry, the HfB2-SiC-MoSi2-phenolic resin slurry is fully stirred and placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0071] 3) Use a brush to apply the HfB2-SiC-MoSi2-phenolic resin slurry to the cleaned curved PC-SiC-C / C sample surface, and dry it in an electric blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the desired thickness of the HfB2-SiC-MoSi2 external coating is obtained.

[0072] 4) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, then cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating.

[0073] 5) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill for 6 h, and then placed in an electric heated blast drying oven at 70° C. for 12 h to obtain a mixed powder.

[0074] 6) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with convex surface facing up in a graphite crucible with a 6 mm thick mixed powder on the bottom, and then continue to add the mixed powder until the mixed powder covers the sample by 6 mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600°C at a rate of 10°C / min under vacuum conditions, keep it warm for 2 hours, then turn off the power and cool it down, and finally obtain the HfB2-SiC-MoSi2 coated PC-SiC-C / C curved surface sample.

[0075] Since the melt changes its flow direction at the corner of the sample during the siliconization process, the flow speed becomes faster, which intensifies the erosion of the pre-coating in this area. Therefore, the corner area of ​​the HfB2-SiC-MoSi2 coating PC-SiC-C / C curved surface sample obtained in this comparative example is as follows: Figure 4 As shown in (a), a large amount of ultra-high temperature ceramic phase loss occurs in the corner area of ​​the curved sample.

[0076] Embodiment 2

[0077] This embodiment includes the following steps:

[0078] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0079] 2) 23wt.% of phenolic resin is fully dissolved in 77wt.% of anhydrous ethanol to obtain phenolic resin solution A; 12wt.% of phenolic resin is fully dissolved in 88wt.% of anhydrous ethanol to obtain phenolic resin solution B; 30wt.% of SiC, 50wt.% of HfB2, and 20wt.% of MoSi2 are added to phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 1; 40wt.% of SiC, 40wt.% of HfB2, and 20wt.% of MoSi2 are added to phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 2, and the fully stirred slurry is placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0080] 3) Use a brush to apply HfB2-SiC-MoSi2-phenolic resin slurry 1 to the corners of the cleaned curved PC-SiC-C / C sample, and apply HfB2-SiC-MoSi2-phenolic resin slurry 2 to the remaining area of ​​the sample surface, and dry it in an electric heated blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0081] 4) Phenolic resin solution A was applied to the corners of the PC-SiC-C / C curved surface sample coated with the HfB2-SiC-MoSi2 external coating, and dried in an electric heated forced air drying oven at 70°C for 20 minutes to obtain a resin carbon barrier layer.

[0082] 5) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating with a resin carbon barrier layer at the corners. Figure 3 (b, e) are the cross-sectional SEM photos and energy spectrum diagrams of the coating sample after carbonization to construct the resin carbon barrier layer. After carbonization, a resin carbon layer with a thickness of about 6 mm is formed on the outside of the ceramic coating in the corner area.

[0083] 6) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill, ball milled for 6 h, and then placed in an electric heated blast drying oven at a temperature of 70° C. for 12 h to obtain a mixed powder.

[0084] 7) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with a resin carbon barrier layer at the corners with the convex surface facing up in a graphite crucible with a 6 mm thick mixed powder on the bottom, and then continue to add the mixed powder until the powder covers the sample by 6 mm. Then place the sealed graphite crucible in a heat treatment furnace, and heat it to 1600°C at a rate of 10°C / min under vacuum conditions, keep it warm for 2 hours, and then turn off the power to cool it down to obtain a PC-SiC-C / C curved surface sample modified with a HfB2-SiC-MoSi2 coating.

[0085] In this embodiment, the HfB2 content at the corners of the sample is increased to 50wt.%, and a resin carbon barrier layer is applied at the same time. The introduction of the resin carbon layer improves the loss of the ultra-high temperature ceramic phase in the local micro-region, and the coating is dense and uniform as a whole. Figure 4 (e) as shown.

[0086] Comparative Example 2

[0087] This comparative example comprises the following steps:

[0088] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0089] 2) 12 wt.% of phenolic resin is fully dissolved in 88 wt.% of anhydrous ethanol to obtain a phenolic resin solution; 30 wt.% of SiC, 50 wt.% of HfB2, and 20 wt.% of MoSi2 are added to the phenolic resin solution to obtain HfB2-SiC-MoSi2-phenolic resin slurry 1; 40 wt.% of SiC, 40 wt.% of HfB2, and 20 wt.% of MoSi2 are added to the phenolic resin solution to obtain HfB2-SiC-MoSi2-phenolic resin slurry 2; the fully stirred slurry is placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0090] 3) Use a brush to apply HfB2-SiC-MoSi2-phenolic resin slurry 1 to the corners of the cleaned curved PC-SiC-C / C sample, and apply HfB2-SiC-MoSi2-phenolic resin slurry 2 to the remaining area of ​​the sample surface, and dry it in an electric heated blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0091] 4) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating. The phase distribution in the corner area of ​​the sample after carbonization is as follows: Figure 2 As shown in (a), the phases are evenly distributed at the corners of the sample. The energy spectrum of the transition zone of the sample after carbonization is as follows: Figure 2 As shown in (b), the gradient change of Hf content is displayed, which realizes the content regulation of the corner area of ​​the curved surface sample, and then realizes the coating preparation of the curved surface sample with different regional components.

[0092] 5) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill for 6 h, and then placed in an electric heated blast drying oven at 70° C. for 12 h to obtain a mixed powder.

[0093] 6) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with the convex surface facing up in a graphite crucible with a 6mm thick mixed powder on the bottom, and then continue to add the mixed powder until the mixed powder covers the sample by 6mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600℃ at a rate of 10℃ / min under vacuum conditions, keep it warm for 2h, then turn off the power and cool it down to obtain a PC-SiC-C / C curved surface sample modified with HfB2-SiC-MoSi2 coating.

[0094] In this comparative example, the pre-coating layer is applied in different regions, and the content of HfB2 at the corners is increased to 50wt.%. The appropriate increase in the content of HfB2 reduces its loss to a certain extent and improves the problem of uneven coating composition at the corners. However, there is still a loss of ultra-high temperature ceramic phase in local micro-regions, such as Figure 4 (b) as shown.

[0095] Comparative Example 3

[0096] This comparative example comprises the following steps:

[0097] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0098] 2) 12 wt.% of phenolic resin is fully dissolved in 88 wt.% of anhydrous ethanol to obtain a phenolic resin solution; 20 wt.% of SiC, 60 wt.% of HfB2, and 20 wt.% of MoSi2 are added to the phenolic resin solution to obtain HfB2-SiC-MoSi2-phenolic resin slurry 1; 40 wt.% of SiC, 40 wt.% of HfB2, and 20 wt.% of MoSi2 are added to the phenolic resin solution to obtain HfB2-SiC-MoSi2-phenolic resin slurry 2; the fully stirred slurry is placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0099] 3) Use a brush to apply HfB2-SiC-MoSi2-phenolic resin slurry 1 to the corners of the cleaned curved PC-SiC-C / C sample, and apply HfB2-SiC-MoSi2-phenolic resin slurry 2 to the remaining area of ​​the sample surface, and dry it in an electric heated blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0100] 4) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200℃ for 1h, and then carbonized in an argon atmosphere at 900℃ for 2h to obtain a HfB2-SiC-MoSi2 pre-coating. The distribution of each phase in the corner area of ​​the sample after carbonization is as follows Figure 2 As shown in (c), the phases are evenly distributed at the corners of the sample. The energy spectrum of the transition zone of the sample after carbonization is as follows: Figure 2 As shown in (d), the gradient change of Hf content is displayed, which realizes the content regulation of the corner area of ​​the curved surface sample, and then realizes the coating preparation of the curved surface sample with different regional components.

[0101] 5) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill for 6 h, and then placed in an electric heated blast drying oven at 70° C. for 12 h to obtain a mixed powder.

[0102] 6) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with the convex surface facing up in a graphite crucible with a 6mm thick mixed powder on the bottom, and then continue to add the mixed powder until the mixed powder covers the sample by 6mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600℃ at a rate of 10℃ / min under vacuum conditions, keep it warm for 2h, then turn off the power and cool it down, and finally obtain the HfB2-SiC-MoSi2 coated modified PC-SiC-C / C curved surface sample.

[0103] In this comparative example, the pre-coating layer was applied in different regions, and the HfB2 content at the corners was increased to 60wt.%. The ultra-high temperature ceramic phase in the corners of the sample was retained in the local micro-regions. However, due to the excessively high HfB2 content, the thermal expansion coefficients of the outer coating and the inner coating were seriously mismatched, and most of the outer coating peeled off. Figure 4 (c) as shown.

[0104] Comparative Example 4

[0105] This comparative example comprises the following steps:

[0106] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0107] 2) 23wt.% of phenolic resin is fully dissolved in 77wt.% of anhydrous ethanol to obtain phenolic resin solution A; 12wt.% of phenolic resin is fully dissolved in 88wt.% of anhydrous ethanol to obtain phenolic resin solution B, 20wt.% of SiC, 60wt.% of HfB2, and 20wt.% of MoSi2 are added to phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 1, 40wt.% of SiC, 40wt.% of HfB2, and 20wt.% of MoSi2 are added to phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 2, and the fully stirred slurry is placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0108] 3) Use a brush to apply HfB2-SiC-MoSi2-phenolic resin slurry 1 to the corner areas of the cleaned curved PC-SiC-C / C sample, and apply HfB2-SiC-MoSi2-phenolic resin slurry 2 to the remaining part of the sample surface, and dry it in an electric blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0109] 4) Phenolic resin solution A was applied to the corners of the PC-SiC-C / C curved surface sample coated with the HfB2-SiC-MoSi2 external coating, and dried in an electric heated forced air drying oven at a temperature of 70°C for 20 minutes to obtain a resin carbon barrier layer.

[0110] 5) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating with a resin carbon barrier layer at the corners. Figure 3 (c, f) are the cross-sectional SEM photos and energy spectrum diagrams of the coating sample after carbonization to construct the resin carbon barrier layer. After carbonization, a resin carbon layer with a thickness of about 6 mm is formed on the outside of the ceramic coating in the corner area.

[0111] 6) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill, ball milled for 6 h, and then placed in an electric heated blast drying oven at a temperature of 70° C. for 12 h to obtain a mixed powder.

[0112] 7) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with resin carbon barrier layer at the corners with the convex surface facing up in a graphite crucible with a 6mm thick mixed powder on the bottom, and then continue to add mixed powder until the mixed powder covers the sample by 6mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600℃ at a rate of 10℃ / min under vacuum conditions, keep it warm for 2h, and then turn off the power to cool it down to obtain a PC-SiC-C / C curved surface sample modified with HfB2-SiC-MoSi2 coating.

[0113] In this comparative example, the HfB2 content at the corners of the sample was increased to 60wt.%, and a resin carbon barrier layer was applied at the same time. However, due to the mismatch of thermal expansion coefficients, peeling of the outer coating still occurred in some areas. Figure 4 (f) as shown.

[0114] Embodiment 3

[0115] This embodiment includes the following steps:

[0116] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0117] 2) 23wt.% of phenolic resin is fully dissolved in 77wt.% of anhydrous ethanol to obtain phenolic resin solution A; 12wt.% of phenolic resin is fully dissolved in 88wt.% of anhydrous ethanol to obtain phenolic resin solution B, 35wt.% of SiC, 45wt.% of HfB2, and 20wt.% of MoSi2 are added to phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 1, 40wt.% of SiC, 40wt.% of HfB2, and 20wt.% of MoSi2 are added to phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 2, and the fully stirred slurry is placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0118] 3) Use a brush to apply HfB2-SiC-MoSi2-phenolic resin slurry 1 to the corners of the cleaned curved PC-SiC-C / C sample, and apply HfB2-SiC-MoSi2-phenolic resin slurry 2 to the remaining area of ​​the sample surface, and dry it in an electric heated blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0119] 4) Phenolic resin solution A was applied to the corners of the PC-SiC-C / C curved surface sample coated with the HfB2-SiC-MoSi2 external coating, and dried in an electric heated forced air drying oven at a temperature of 70°C for 20 minutes to obtain a resin carbon barrier layer.

[0120] 5) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating with a resin carbon barrier layer at the corners.

[0121] 6) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill, ball milled for 6 h, and then placed in an electric heated blast drying oven at a temperature of 70° C. for 12 h to obtain a mixed powder.

[0122] 7) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with resin carbon barrier layer at the corners with the convex surface facing up in a graphite crucible with a 6mm thick mixed powder on the bottom, and then continue to add mixed powder until the mixed powder covers the sample by 6mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600℃ at a rate of 10℃ / min under vacuum conditions, keep it warm for 2h, then turn off the power and cool it down, and finally obtain the HfB2-SiC-MoSi2 coating modified PC-SiC-C / C curved surface sample.

[0123] Embodiment 4

[0124] This embodiment includes the following steps:

[0125] 1) The density of the embedded SiC inner coating is 1.7 g / cm 3 The curved surface C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 5 times, each cleaning time was 30 min, and dried in an electric heated blast drying oven at a temperature of 70 °C for 8 h.

[0126] 2) 23wt.% of phenolic resin is fully dissolved in 77wt.% of anhydrous ethanol to obtain phenolic resin solution A; 12wt.% of phenolic resin is fully dissolved in 88wt.% of anhydrous ethanol to obtain phenolic resin solution B, and then 35wt.% of SiC, 45wt.% of HfB2, and 20wt.% of MoSi2 are added to the phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 1, and 40wt.% of SiC, 40wt.% of HfB2, and 20wt.% of MoSi2 are added to the phenolic resin solution B to obtain HfB2-SiC-MoSi2-phenolic resin slurry 2, and the fully stirred slurry is placed in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry.

[0127] 3) Use a brush to apply HfB2-SiC-MoSi2-phenolic resin slurry 1 to the corners of the cleaned curved PC-SiC-C / C sample, and apply HfB2-SiC-MoSi2-phenolic resin slurry 2 to the remaining area of ​​the sample surface, and dry it in an electric heated blast drying oven at 70°C for 20 minutes. Repeat the above brushing-drying steps until the HfB2-SiC-MoSi2 external coating of the desired thickness is obtained.

[0128] 4) Phenolic resin solution A was applied to the corners of the PC-SiC-C / C curved surface sample coated with the HfB2-SiC-MoSi2 external coating, and dried in an electric heated forced air drying oven at a temperature of 70°C for 20 minutes to obtain a resin carbon barrier layer.

[0129] 5) The coated sample was placed in an Al2O3 ark and placed in a tubular heat treatment furnace, cured at 200°C for 1 h, and then carbonized in an argon atmosphere at 900°C for 2 h to obtain a HfB2-SiC-MoSi2 pre-coating with a resin carbon barrier layer at the corners.

[0130] 6) 71 wt.% Si powder, 14 wt.% SiC and 15 wt.% C powder were mixed and poured into a ball mill, ball milled for 6 h, and then placed in an electric heated blast drying oven at a temperature of 70° C. for 12 h to obtain a mixed powder.

[0131] 7) Place the HfB2-SiC-MoSi2 pre-coated PC-SiC-C / C curved surface sample with resin carbon barrier layer at the corners with the convex surface facing up in a graphite crucible with 8mm thick Si, SiC and C powder mixed at the bottom, and then continue to add the mixed powder until the mixed powder covers the sample by 8mm. Then place the sealed graphite crucible in a heat treatment furnace, heat it to 1600℃ at a rate of 10℃ / min under vacuum conditions, keep it warm for 2h, then turn off the power and cool it down to obtain the HfB2-SiC-MoSi2 coating modified PC-SiC-C / C curved surface sample.

[0132] Embodiment 5

[0133] The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to the present invention comprises:

[0134] 1) Preparation of single-phase / multi-phase ceramic coatings on the surface of curved C / C composites;

[0135] 11) The density of the embedded SiC inner coating is 1.7-1.8 g / cm 3 The curved C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 4 times, each cleaning time was 20 min, and then dried in an electric heated blast drying oven at a temperature of 60 °C for 6 h.

[0136] 12) dissolving 10 wt.% of a mixture of one or more of phenolic resin, epoxy resin, polyester resin and furan resin in 60 wt.% of anhydrous ethanol to obtain a resin solution A;

[0137] Fully dissolving 5 wt.% of a mixture of one or more of phenolic resin, epoxy resin, polyester resin, and furan resin in 70 wt.% of anhydrous ethanol to obtain a resin solution B;

[0138] Add one or more of ZrB2, HfB2, SiC, HfSi2, MoSi2, ZrSi2 and TaSi2 into the resin solution B in a ratio of 20wt. %: 40wt. %: 5wt. %, stir thoroughly and place in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry to obtain a mixed slurry.

[0139] 13) Use a brush to apply the mixed slurry to the surface of the curved C / C composite material, and dry it in an electric heated air drying oven at a temperature of 60° C. for 10 min. Repeat the above brushing-drying steps until a ceramic coating of the desired thickness is obtained on the surface of the curved C / C composite material.

[0140] 2) preparing a resin carbon barrier layer on the surface of the test piece obtained in step 1);

[0141] 21) Coating the resin solution A on the corners of the test piece obtained in step 1) and drying in an electric heated blast drying oven at a temperature of 60° C. for 10 min to obtain a resin carbon barrier layer;

[0142] 22) The test piece obtained in step 21) is placed in an Al2O3 ark and placed in a tubular heat treatment furnace, then cured at 150°C for 1 hour, and then carbonized in an argon atmosphere at 900°C for 2 hours to obtain a ceramic pre-coating with a resin carbon barrier layer at the corners.

[0143] 23) 50 wt.% Si powder, 5 wt.% SiC and 10 wt.% C powder were mixed and poured into a ball mill for 5 h, and then placed in an electric heated blast drying oven at 60° C. for 10 h to obtain a mixed powder;

[0144] 24) Place the test piece obtained in step 22) in a graphite crucible with a 5 mm thick mixed powder on the bottom, and then add the mixed powder to the graphite crucible until the mixed powder covers the test piece by 5 to 10 mm. Then seal the graphite crucible and place it in a heat treatment furnace. Then, heat it to 1500°C at a rate of 4°C / min under vacuum conditions and keep it warm for 1 hour. Then, turn off the power and cool it down to obtain a PC-SiC-C / C curved surface sample modified with a ceramic coating.

[0145] Embodiment 6

[0146] The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to the present invention comprises:

[0147] 1) Preparation of single-phase / multi-phase ceramic coatings on the surface of curved C / C composites;

[0148] 11) The density of the embedded SiC inner coating is 1.7-1.8 g / cm 3 The curved C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 6 times, each cleaning time was 40 min, and then dried in an electric hot air drying oven at a temperature of 100 °C for 10 h.

[0149] 12) fully dissolving 30 wt.% of a mixture of one or more of phenolic resin, epoxy resin, polyester resin, and furan resin in 80 wt.% of anhydrous ethanol to obtain a resin solution A;

[0150] Fully dissolving 20 wt.% of a mixture of one or more of phenolic resin, epoxy resin, polyester resin, and furan resin in 90 wt.% of anhydrous ethanol to obtain a resin solution B;

[0151] Add one or more of ZrB2, HfB2, SiC, HfSi2, MoSi2, ZrSi2 and TaSi2 into the resin solution B in a ratio of 40wt.%:60wt.%:20wt.%, stir thoroughly and place in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry to obtain a mixed slurry.

[0152] 13) Use a brush to apply the mixed slurry to the surface of the curved C / C composite material, and dry it in an electric heated blast drying oven at a temperature of 100° C. for 20 minutes. Repeat the above brushing-drying steps until a ceramic coating of the desired thickness is obtained on the surface of the curved C / C composite material.

[0153] 2) preparing a resin carbon barrier layer on the surface of the test piece obtained in step 1);

[0154] 21) Coating the resin solution A on the corners of the test piece obtained in step 1) and drying in an electric heated air drying oven at a temperature of 100° C. for 20 min to obtain a resin carbon barrier layer;

[0155] 22) The test piece obtained in step 21) is placed in an Al2O3 ark and placed in a tubular heat treatment furnace, then cured at 200°C for 2 hours, and then carbonized in an argon atmosphere at 1200°C for 4 hours to obtain a ceramic pre-coating with a resin carbon barrier layer at the corners.

[0156] 23) 80 wt.% Si powder, 25 wt.% SiC and 25 wt.% C powder were mixed and poured into a ball mill for 8 h, and then placed in an electric heated blast drying oven at a temperature of 100° C. for 16 h to obtain a mixed powder;

[0157] 24) The test piece obtained in step 22) is placed in a graphite crucible with a 10 mm thick mixed powder on the bottom, and then the mixed powder is added to the graphite crucible until the mixed powder covers the test piece by 10 mm. The graphite crucible is sealed and then placed in a heat treatment furnace. The temperature is then raised to 1700°C at a rate of 10°C / min under vacuum conditions and kept warm for 2 hours. The power is then turned off and the temperature is cooled to obtain a PC-SiC-C / C curved surface sample modified with a ceramic coating.

[0158] Embodiment 7

[0159] The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to the present invention comprises:

[0160] 1) Preparation of single-phase / multi-phase ceramic coatings on the surface of curved C / C composites;

[0161] 11) The density of the embedded SiC inner coating is 1.7-1.8 g / cm 3The curved C / C composite material (PC-SiC-C / C) was ultrasonically cleaned with deionized water for 4 times, each cleaning time was 30 min, and then dried in an electric heated blast drying oven at a temperature of 80 °C for 8 h.

[0162] 12) fully dissolving 200 wt.% of a mixture of one or more of phenolic resin, epoxy resin, polyester resin, and furan resin in 70 wt.% of anhydrous ethanol to obtain a resin solution A;

[0163] A mixture of 10 wt.% of one or more of phenolic resin, epoxy resin, polyester resin and furan resin is fully dissolved in 80 wt.% of anhydrous ethanol to obtain a resin solution B;

[0164] Add one or more of ZrB2, HfB2, SiC, HfSi2, MoSi2, ZrSi2 and TaSi2 into the resin solution B in the ratio of 30wt.%:50wt.%:10wt.%, stir thoroughly and place in an ultrasonic cleaner for ultrasonic dispersion until there are no obvious agglomerated particles in the slurry to obtain a mixed slurry.

[0165] 13) Use a brush to apply the mixed slurry to the surface of the curved C / C composite material, and dry it in an electric heated air drying oven at a temperature of 80° C. for 15 minutes, and repeat the above brushing-drying steps until a ceramic coating of the desired thickness is obtained on the surface of the curved C / C composite material.

[0166] 2) preparing a resin carbon barrier layer on the surface of the test piece obtained in step 1);

[0167] 21) Coating the resin solution A on the corners of the test piece obtained in step 1) and drying in an electric heated blast drying oven at a temperature of 80° C. for 15 min to obtain a resin carbon barrier layer;

[0168] 22) The test piece obtained in step 21) is placed in an Al2O3 ark and placed in a tubular heat treatment furnace, then cured at 180°C for 1.5 hours, and then carbonized in an argon atmosphere at 1000°C for 3 hours to obtain a ceramic pre-coating with a resin carbon barrier layer at the corners.

[0169] 23) 60wt.% Si powder, 15wt.% SiC and 15wt.% C powder were mixed and poured into a ball mill for 6h, and then placed in an electric heated blast drying oven at 80°C for 11h to obtain a mixed powder;

[0170] 24) Place the test piece obtained in step 22) in a graphite crucible with a mixed powder of 8 mm thickness on the bottom, and then add the mixed powder to the graphite crucible until the mixed powder covers the test piece by 8 mm. Then seal the graphite crucible and place it in a heat treatment furnace. Then, heat it to 1600°C at a rate of 8°C / min under vacuum conditions and keep it warm for 1.5 hours. Then, turn off the power and cool it down to obtain a PC-SiC-C / C curved surface sample modified with a ceramic coating.

[0171] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0172] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0173] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for improving the uniformity of the coating composition of a curved C / C composite material, characterized in that: The following steps are involved: A single-phase / multi-phase ceramic coating is prepared on the surface of a curved C / C composite material to obtain a test piece; A resin carbon barrier layer is prepared on the surface of the specimen, and then the specimen is subjected to siliconization treatment.

2. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 1, characterized in that: The process of preparing a single-phase / multi-phase ceramic coating on the surface of a curved C / C composite material is as follows: 11) Cleaning and drying the curved surface C / C composite material; 12) dissolving resin 1 in anhydrous ethanol A to obtain resin solution A; Dissolve resin 2 in anhydrous ethanol B to obtain resin solution B, add one or a mixture of ZrB2 or HfB2, SiC, HfSi2, MoSi2, ZrSi2 and TaSi2 to the resin solution B, stir and then disperse by ultrasonic to obtain a mixed slurry; 13) The mixed slurry is applied to the surface of the curved C / C composite material and dried to obtain a ceramic coating.

3. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 2, characterized in that: The resin 1 is a mixture of one or more resins selected from the group consisting of phenolic resin, epoxy resin, polyester resin and furan resin.

4. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 2, characterized in that: The mass ratio of resin 1 to anhydrous ethanol A is 10-30:60-80.

5. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 2, characterized in that: The mass ratio of the resin 2, anhydrous ethanol, BZrB2 or HfB2, SiC and a mixture of one or more of HfSi2, MoSi2, ZrSi2 and TaSi2 is 5-20:70-90:20-40:40-60:5-20.

6. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 1, characterized in that: The process of preparing a resin carbon barrier layer on the surface of the test piece and then performing siliconization treatment on the test piece is as follows: 21) Coating the resin solution A on the corners of the specimen, and then drying it to obtain a resin carbon barrier layer; 22) The test piece obtained in step 21) is cured at 150-200° C., and then carbonized in an argon atmosphere at 900-1200° C. to obtain a ceramic pre-coating with a resin carbon barrier layer at the corners. 23) preparing mixed powder; 24) The test piece obtained in step 22) is placed in a graphite crucible with a 5-10 mm thick mixed powder on the bottom, and then the mixed powder is added to the graphite crucible until the mixed powder covers the test piece by 5-10 mm. The graphite crucible is then sealed, and then the temperature is raised to 1500-1700°C under vacuum conditions, and then the temperature is lowered after being kept warm.

7. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 6, characterized in that: The operation process of step 23) is: Si powder, SiC and C powder are mixed, ball-milled and then dried to obtain a mixed powder.

8. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 6, characterized in that: The mass ratio of Si powder, SiC and C powder is 50-80:5-25:10-25.

9. The method for improving the uniformity of the coating composition on the surface of a curved C / C composite material according to claim 6, characterized in that: Under vacuum conditions, the temperature is raised to 1500-1700°C at a rate of 4-10°C / min.

10. A curved C / C composite material surface coating, characterized in that: The method for improving the uniformity of the surface coating composition of a curved C / C composite material according to any one of claims 1 to 9 is used for preparation.

Images