A polymer-derived nanocarbon-containing ablative-resistant ceramic coating and a method of making the same

Abstract

The present application relates to a kind of polymer-derived nano-carbon ablation-resistant ceramic coating and its preparation method, its structural features are in that uniform dispersion nano-carbon material is contained in the preparation of composite ceramic by polymer conversion ceramic method, and ablation-resistant ceramic coating containing polymer-derived nano-carbon is prepared by plasma spraying method.Due to the addition of unsaturated bond-containing organic carbon source in precursor, by the front end design of polymer molecular structure, it is in-situ generated rich nano-carbon composite ceramic in inorganic transformation process, realize the uniform distribution of nano-carbon material in ceramic, improve the heat conduction performance of ceramic coating, reduce the heat accumulation of composite material in ablation environment due to aerodynamic heating, realize high-efficiency heat dissipation and improve the ablation-resistant protection life.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-ablation coatings and relates to an anti-ablation ceramic coating of polymer-derived nano-carbon and a preparation method thereof. Background Art

[0002] With the rapid development of space technology, high-speed aircraft face extremely harsh environments such as high-speed airflow erosion, drastic temperature changes, and ultra-high temperature ablation during their service. These conditions cause excessive heat loads on the aircraft's external protection and engine components, affecting their normal flight. Therefore, in order to reduce stagnation ablation caused by local heat accumulation due to aerodynamic heating, maintain the aircraft's intact aerodynamic shape, and protect the power system from burning, there is an urgent need for lightweight, high-strength, and ablation-resistant thermal protection materials that are resistant to extreme high temperatures and thermal cycling erosion. Currently, commonly used composite materials such as carbon / carbon (C / C), carbon / silicon carbide (C / SiC), and fiber-reinforced ultra-high temperature ceramics have high oxidation sensitivity and insufficient ablation resistance, which seriously limits their practical application in extreme ultra-high temperature environments. Preparing ultra-high temperature ceramic (UHTCs) coatings with high melting points and good chemical stability on the surface of composite materials is an effective measure to improve their high-temperature thermal protection.

[0003] UHTC coatings, such as HfC, ZrC, and TaC, are easily oxidized during the ablation process, forming oxide ceramics with low thermal conductivity. This makes it difficult to effectively dissipate the high heat from the coating surface and generates significant structural thermal stress, leading to defects such as cracks. This makes it impossible to effectively protect high-heat components in ultra-high-temperature environments. Therefore, by adding highly thermally conductive materials such as AlN, BN, graphene, and CNTs, it is expected to significantly improve the coating's thermal conductivity, thereby reducing surface temperatures and improving the coating's ablation stability. For example, Chinese Patent 202311148466.1 discloses a powder for plasma spraying, a method for preparing a surface coating, and its application. Silicon powder, silicon carbide powder, carbon powder, and polyvinyl alcohol are mechanically mixed and then plasma sprayed to produce a surface coating with excellent electrical and thermal conductivity. The average particle size of the added carbon powder ranges from 0.1 to 1 μm. Because the large size of the carbon microspheres makes it difficult to form an effective thermal path, the carbon content in the patent often requires greater than 15 wt.% to achieve good thermal conductivity. For example, the literature 1 "Yu Y, Feng G, Jia Y, et al. Nanosized (Zr, Hf) O2 coating reinforced by AlN whiskers for the ablation protection of SiCcoated C / C composites [J]. Journal of the European Ceramic Society, 2023, 43: 3959-3968." reported the preparation and anti-ablation performance study of (Zr, Hf) O2 coating modified with high thermal conductivity AlN whiskers. The study believes that the surface ablation temperature of AlN whisker reinforced (Zr, Hf) O2 coating is about 100 ° C lower than that of (Zr, Hf) O2 coating, thus having better anti-ablation performance. This is because AlN whiskers have high thermal conductivity, which can quickly transfer and dissipate surface heat. Due to the agglomeration effect of nanomaterials, the AlN whiskers need to be modified by ultrasound and acid in this study to improve their dispersion effect. Reference 2 "Shi A, Yang X, Fang C, et al. Effect of CNTs addition on microstructure, ablation property and mechanism of ZrC-SiC coating for C / C-ZrC-SiC composites[J]. Vacuum, 2020, 172: 109099." CNTs-modified ZrC-SiC coating was prepared by ball-milling ZrSi2 and CNT and then using the embedding method.The study shows that compared with ZrC-SiC coating, ZrC-SiC-CNTs coating has worse anti-ablation performance due to increased porosity and more local defects in the coating due to CNT agglomeration.

[0004] Therefore, improving the dispersion of nanocarbon materials in anti-ablative coatings to produce dense, uniform, and highly effective anti-ablative coatings is a pressing issue. To address this, polymer-converted ceramics (PCCs) are being used to in situ couple ultrahigh-temperature ceramics and nanocarbon materials to produce nanoscale, uniformly dispersed composite ceramic powders. By increasing the amount of unsaturated carbon bonds in the modified precursor, the carbon-containing groups are gradually converted into nanocarbon materials during pyrolysis and high-temperature heat treatment. Using this composite powder as a raw material, supersonic plasma spraying can be used to prepare anti-ablative coatings containing polymer-derived nanocarbons. This improves the coating's thermal conductivity, reduces the surface temperature of the material during service, and contributes to enhanced anti-ablative performance. Summary of the Invention

[0005] Technical problems to be solved

[0006] To overcome the shortcomings of existing technologies, the present invention proposes a polymer-derived nanocarbon-based ablation-resistant ceramic coating and its preparation method. These coatings address the low thermal conductivity, severe stagnation point ablation, and difficulty in achieving uniform dispersion of nanocarbon in ultrahigh-temperature ceramic coatings. The polymer-derived nanocarbon-based ablation-resistant ceramic coating, prepared using a polymer conversion and thermal spraying method, boasts high density, excellent thermal conductivity, and uniform phase distribution, potentially overcoming the stagnation point ablation associated with temperature concentration in conventional ablation-resistant ceramic coatings.

[0007] Technical Solution

[0008] A method for preparing an anti-ablation ceramic coating containing polymer-derived nanocarbon, characterized in that a polymer-to-ceramic conversion method is used to prepare a composite ceramic, and the composite ceramic is used to prepare the anti-ablation ceramic coating; the composite ceramic contains uniformly dispersed nanocarbon material, and the preparation steps are as follows:

[0009] Step 1: Using a Schlenk apparatus, a polymer precursor, a transition metal compound, an organic carbon source containing an unsaturated bond, and an organic solvent are placed in a Schlenk flask and reacted with magnetic stirring at 80-150°C for 2-12 hours under Ar atmosphere. The organic solvent is then removed under vacuum to obtain a single-source precursor powder.

[0010] Step 2: The single-source precursor powder is placed in a tube furnace and, under Ar atmosphere protection, cross-linked, cured, cracked, and subjected to high-temperature heat treatment. The inorganicization of the organic carbon functional groups containing unsaturated bonds in the single-source precursor yields a composite ceramic powder rich in nanocarbon materials.

[0011] The cross-linking curing temperature is 100-300°C;

[0012] The cracking temperature is 900-1200°C;

[0013] The heat treatment temperature is 1400-1900°C;

[0014] The holding time during the cross-linking, curing, cracking and high-temperature heat treatment process is 2 to 5 hours;

[0015] Step 3: The composite ceramic powder containing polymer-derived nanocarbon, ZrC, polyvinyl alcohol solution, anhydrous ethanol and deionized water are ball-milled to prepare a mixed slurry, the slurry is spray-granulated and then sprayed onto the surface of the substrate material by supersonic plasma spraying to obtain an anti-ablation ceramic coating containing polymer-derived nanocarbon.

[0016] In step 1, the polymer precursor is polycarbosilane, polynitrosilane, polysiloxane or polyborosilazane.

[0017] The organic carbon source containing unsaturated bonds in step 1 contains one or more organic substances selected from ethylene, propylene or benzene rings.

[0018] The organic carbon source containing unsaturated bonds in step 1 is divinylbenzene (DVB), dicumyl peroxide, ferrocene, isoprene, phenylacetylene, melamine, dopamine, vinyltriethoxysilane or vinylpyrrolidone.

[0019] The organic solvent in step 1 includes one or more of toluene, xylene, and furan.

[0020] The heating rate in step 2 is 3-10°C / min.

[0021] In the step 3, the ratio of the composite ceramic powder containing polymer-derived nanocarbon, ZrC, polyvinyl alcohol solution, anhydrous ethanol and deionized water is 1 to 3:1 to 3:4:1:1.

[0022] In step 3, the matrix material is graphite coated with a SiC coating, a C / C composite material, a C / SiC composite material, or a C / ultra-high temperature ceramic composite material.

[0023] An ablation-resistant ceramic coating prepared by the method is characterized in that an organic carbon source containing unsaturated bonds is added to a precursor, and a nanocarbon-rich composite ceramic is generated in situ during the inorganic transformation process, and the nanocarbon material is evenly distributed in the ceramic.

[0024] The plasma spraying method is used to prepare an anti-ablation ceramic coating containing polymer-derived nanocarbon, thereby improving the thermal conductivity of the prepared ceramic coating, reducing heat accumulation caused by aerodynamic heating of the composite material in an ablation environment, achieving efficient heat dissipation and improving the life of the anti-ablation protection. The surface temperature is reduced by 100 to 200°C, and the mass and linear ablation rate are reduced by approximately 0.9 times and 0.8 times, respectively.

[0025] Beneficial effects

[0026] The present invention proposes a polymer-derived nanocarbon anti-ablation ceramic coating and a preparation method thereof. Its structural characteristics are that a polymer-conversion ceramic method is used to prepare a composite ceramic containing uniformly dispersed nanocarbon materials, and the anti-ablation ceramic coating containing polymer-derived nanocarbon is prepared by a plasma spraying method. Due to the addition of an organic carbon source containing unsaturated bonds to the precursor, the front-end design of the polymer molecular structure enables the in-situ generation of nanocarbon-rich composite ceramics during the inorganic transformation process, thereby achieving uniform distribution of the nanocarbon material in the ceramic, improving the thermal conductivity of the prepared ceramic coating, reducing the heat accumulation caused by aerodynamic heating of the composite material in an ablation environment, achieving efficient heat dissipation, and improving the anti-ablation protection life. The components changed in the present invention are not simple to determine.

[0027] This invention utilizes polymer molecular structure design to generate nanocarbon in situ during the inorganic conversion process, using an organic carbon source containing unsaturated bonds during the ceramicization process to address the agglomeration problem of nanomaterials. The thermal conductivity of the ceramic coating is improved by mixing a composite ceramic containing polymer-derived nanocarbon with ZrC to prepare a spray coating. The highly thermally conductive nanocarbon-enhanced coating achieves rapid heat dissipation, thereby increasing the coating's ablation resistance lifespan. Compared to existing technologies, this process offers advantages such as simple equipment, simple operation, a short preparation cycle, good uniformity, and a wide range of process parameter applicability. The resulting ceramic coating containing polymer-derived nanocarbon exhibits higher thermal conductivity than pure ceramic coatings, can reduce the coating's surface temperature by approximately 200°C, and is beneficial for reducing stagnation point ablation and improving ablation resistance, thus offering promising development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 TEM (a, c) and HRTEM (b, d) images of polymer-converted SiC / TaC (a, b) and SiC / TaC@C ceramic powders (c, d). They are the PDCs powders obtained in Example 1 and Comparative Example 1, respectively. Figure 1 It can be seen that when DVB is added during the synthesis of a single-source precursor, the SiC / TaC@C powder obtained by pyrolysis is rich in crystalline nanocarbon materials.

[0029] Figure 2The XRD pattern of the spray coating surface (a) and the HRTEM image of the powder in the ZrC-SiC / TaC@C coating (b). Figure 2 The XRD pattern shows that the primary phase of the sprayed coating is ZrC, with peaks for SiC and TaC also detected. Furthermore, ZrO₂ appears due to unavoidable oxidation during the atmospheric spraying process. HRTEM images reveal that, in addition to the phases detected by XRD, crystalline nanocarbon materials are also observed in the coating.

[0030] Figure 3 Surface temperature curves of the two coating samples obtained in Example 1 and Comparative Example 1 during the ablation process. Figure 3 The surface temperature of the ZrC-SiC / TaC coating reached a maximum of 2224°C, while that of the ZrC-SiC / TaC@C coating containing polymer-derived nanocarbon was only 2032°C, a difference of approximately 200°C. This indicates that increasing the amount of DVB in the precursor to generate nanocarbons helps reduce the ablation surface temperature of the modified coating, thereby achieving a lower ablation rate and improving the material's ablation resistance. DETAILED DESCRIPTION

[0031] The present invention will now be further described with reference to the embodiments and accompanying drawings:

[0032] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments.

[0033] Example 1

[0034] Step 1: Dissolve a polycarbosilane precursor, tantalum pentachloride, and DVB in a mass ratio of 7:3:1 in xylene organic solvent, place the mixture in a Schlenk flask, and react at 80° C. with magnetic stirring for 3 h under Ar atmosphere protection.

[0035] Step 2: After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 60° C. under vacuum to obtain a single-source precursor powder of SiC / TaC@C ceramics.

[0036] Step 3: Place the single-source precursor powder of the SiC / TaC@C ceramic in a tube furnace. Under Ar atmosphere, heat the furnace at a rate of 5°C / min to crosslink and solidify the precursor at 300°C and then pyrolyze it at 1000°C. After the holding period, turn off the heating power and cool the furnace down.

[0037] Step 4: The cracked powder was transferred to a high-temperature heat treatment furnace. Under the protection of Ar atmosphere, the furnace temperature was raised to 1800°C at a heating rate of 5°C / min and kept at this temperature for 2 hours, and then cooled with the furnace to obtain SiC / TaC@C ceramic powder.

[0038] Step 5: ZrC and polymer-converted SiC / TaC@C ceramic powders were mixed in a mass ratio of 7:3. The mixed ceramic powders were mixed with polyvinyl alcohol solution, anhydrous ethanol and deionized water in a mass ratio of 4:4:1:1 in a ball mill for 4 h to obtain a uniform ceramic slurry suspension.

[0039] Step 6: The ceramic suspension is fed into the nozzle of the spray granulation equipment through a peristaltic pump, and the inlet temperature and outlet temperature are controlled at 330° C. and 100° C., respectively, to obtain spherical ceramic powder.

[0040] Step 7: The granulated spherical powder is fed into the plasma jet through a powder feeder, and a ZrC-SiC / TaC@C coating containing polymer-derived nanocarbon is prepared on the surface of the SiC-C / C composite material using a supersonic plasma spraying device.

[0041] Example 2

[0042] Step 1: Dissolve a polycarbosilane precursor, tantalum pentachloride, and DVB in a mass ratio of 7:3:0.4 in xylene organic solvent, place the mixture in a Schlenk flask, and react at 80° C. with magnetic stirring for 3 h under Ar atmosphere protection.

[0043] Step 2: After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 60° C. under vacuum to obtain a single-source precursor powder of SiC / TaC@C ceramics.

[0044] Step 3: Place the single-source precursor powder of the SiC / TaC@C ceramic in a tube furnace. Under Ar atmosphere, heat the furnace at a rate of 5°C / min to crosslink and solidify the precursor at 300°C and then pyrolyze it at 1000°C. After the holding period, turn off the heating power and cool the furnace down.

[0045] Step 4: The cracked powder was transferred to a high-temperature heat treatment furnace. Under the protection of Ar atmosphere, the furnace temperature was raised to 1600°C at a heating rate of 5°C / min and kept at this temperature for 2 hours, and then cooled with the furnace to obtain SiC / TaC@C ceramic powder.

[0046] Step 5: ZrC and polymer-converted SiC / TaC@C ceramic powders were mixed in a mass ratio of 7:3. The mixed ceramic powders were mixed with polyvinyl alcohol solution, anhydrous ethanol and deionized water in a mass ratio of 4:4:1:1 in a ball mill for 4 h to obtain a uniform ceramic slurry suspension.

[0047] Step 6: The ceramic suspension is fed into the nozzle of the spray granulation equipment through a peristaltic pump, and the inlet temperature and outlet temperature are controlled to be approximately 330° C. and 100° C., respectively, to obtain spherical ceramic powder.

[0048] Step 7: The granulated spherical powder is fed into the plasma jet through a powder feeder, and a ZrC-SiC / TaC@C coating containing polymer-derived nanocarbon is prepared on the surface of the SiC-C / C composite material using a supersonic plasma spraying device.

[0049] Example 3

[0050] Step 1: Dissolve a polycarbosilane precursor, tantalum pentachloride, and DVB in a mass ratio of 7:3:0.7 in xylene organic solvent, place the mixture in a Schlenk flask, and react at 80° C. with magnetic stirring for 3 h under Ar atmosphere protection.

[0051] Step 2: After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 60° C. under vacuum to obtain a single-source precursor powder of SiC / TaC@C ceramics.

[0052] Step 3: Place the single-source precursor powder of the SiC / TaC@C ceramic in a tube furnace. Under Ar atmosphere, heat the furnace at a rate of 5°C / min to crosslink and solidify the precursor at 300°C and then pyrolyze it at 1000°C. After the holding period, turn off the heating power and cool the furnace down.

[0053] Step 4: The cracked powder was transferred to a high-temperature heat treatment furnace. Under the protection of Ar atmosphere, the furnace temperature was raised to 1600°C at a heating rate of 5°C / min and kept at this temperature for 2 hours, and then cooled with the furnace to obtain SiC / TaC@C ceramic powder.

[0054] Step 5: ZrC and polymer-converted SiC / TaC@C ceramic powders were mixed in a mass ratio of 7:3. The mixed ceramic powders were mixed with polyvinyl alcohol solution, anhydrous ethanol and deionized water in a mass ratio of 4:4:1:1 in a ball mill for 4 h to obtain a uniform ceramic slurry suspension.

[0055] Step 6: The ceramic suspension is fed into the nozzle of the spray granulation equipment through a peristaltic pump, and the inlet temperature and outlet temperature are controlled to be approximately 330° C. and 100° C., respectively, to obtain spherical ceramic powder.

[0056] Step 7: The granulated spherical powder is fed into the plasma jet through a powder feeder, and a ZrC-SiC / TaC@C coating containing polymer-derived nanocarbon is prepared on the surface of the SiC-C / C composite material using a supersonic plasma spraying device.

[0057] Example 4

[0058] Step 1: A polycarbosilane precursor, tantalum pentachloride, and DVB in a mass ratio of 7:3:1 and 5 wt.% of ferrocene were dissolved in a xylene organic solvent, placed in a Schlenk flask, and reacted at 80° C. with magnetic stirring for 3 h under Ar atmosphere protection.

[0059] Step 2: After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 60° C. under vacuum to obtain a single-source precursor powder of SiC / TaC / CNT ceramics.

[0060] Step 3: Place the single-source precursor powder of SiC / TaC / CNT ceramics in a tube furnace. Under Ar atmosphere, heat the furnace at a rate of 5°C / min to crosslink and solidify the precursor at 300°C and then pyrolyze it at 1000°C. After the holding period, turn off the heating power and cool the furnace down.

[0061] Step 4: The cracked powder was transferred to a high-temperature heat treatment furnace. Under the protection of Ar atmosphere, the furnace temperature was raised to 1600°C at a heating rate of 5°C / min and kept at this temperature for 2 hours, and then cooled with the furnace to obtain SiC / TaC / CNT ceramic powder.

[0062] Step 5: ZrC and polymer-converted SiC / TaC / CNT ceramic powders were mixed in a mass ratio of 7:3, and the mixed ceramic powders were mixed with polyvinyl alcohol solution, anhydrous ethanol and deionized water in a mass ratio of 4:4:1:1 in a ball mill for 4 h to obtain a uniform ceramic slurry suspension.

[0063] Step 6: The ceramic suspension is fed into the nozzle of the spray granulation equipment through a peristaltic pump, and the inlet temperature and outlet temperature are controlled at 330° C. and 100° C., respectively, to obtain spherical ceramic powder.

[0064] Step 7: The granulated spherical powder is fed into the plasma jet through a powder feeder, and a ZrC-SiC / TaC / CNT coating containing polymer-derived nanocarbon is prepared on the surface of the SiC-C / C composite material using a supersonic plasma spraying device.

[0065] Example 5

[0066] Step 1: A polycarbosilane precursor, tantalum pentachloride, and DVB in a mass ratio of 14:6:3 and 10 wt.% of ferrocene were dissolved in a xylene organic solvent, placed in a Schlenk flask, and reacted at 80° C. with magnetic stirring for 3 h under Ar atmosphere protection.

[0067] Step 2: After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 60° C. under vacuum to obtain a single-source precursor powder of SiC / TaC / CNT ceramics.

[0068] Step 3: Place the single-source precursor powder of SiC / TaC / CNT ceramics in a tube furnace. Under Ar atmosphere, heat the furnace at a rate of 5°C / min to crosslink and solidify the precursor at 300°C and then pyrolyze it at 1000°C. After the holding period, turn off the heating power and cool the furnace down.

[0069] Step 4: The cracked powder was transferred to a high-temperature heat treatment furnace. Under the protection of Ar atmosphere, the furnace temperature was raised to 1600°C at a heating rate of 5°C / min and kept at this temperature for 2 hours, and then cooled with the furnace to obtain SiC / TaC / CNT ceramic powder.

[0070] Step 5: ZrC and polymer-converted SiC / TaC / CNT ceramic powders were mixed in a mass ratio of 7:3, and the mixed ceramic powders were mixed with polyvinyl alcohol solution, anhydrous ethanol and deionized water in a mass ratio of 4:4:1:1 in a ball mill for 4 h to obtain a uniform ceramic slurry suspension.

[0071] Step 6: The ceramic suspension is fed into the nozzle of the spray granulation equipment through a peristaltic pump, and the inlet temperature and outlet temperature are controlled at 330° C. and 100° C., respectively, to obtain spherical ceramic powder.

[0072] Step 7: The granulated spherical powder is fed into the plasma jet through a powder feeder, and a ZrC-SiC / TaC / CNT coating containing polymer-derived nanocarbon is prepared on the surface of the SiC-C / C composite material using a supersonic plasma spraying device.

[0073] Comparative Example 1

[0074] Step 1: Dissolve a polycarbosilane precursor and tantalum pentachloride in a mass ratio of 7:3 in xylene organic solvent, place the mixture in a Schlenk flask, and react at 80° C. with magnetic stirring for 3 h under Ar atmosphere protection.

[0075] Step 2: After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 60° C. under vacuum to obtain a single-source precursor powder of SiC / TaC ceramics.

[0076] Step 3: Place the single-source precursor powder of SiC / TaC ceramics in a tube furnace. Under Ar atmosphere, increase the temperature at a rate of 5°C / min to crosslink and cure the precursor at 300°C and then pyrolyze it at 1000°C. After the holding period, turn off the heating power and cool the furnace.

[0077] Step 4: The cracked powder was transferred to a high-temperature heat treatment furnace. Under the protection of Ar atmosphere, the furnace temperature was raised to 1800°C at a heating rate of 5°C / min and kept at this temperature for 2 hours, and then cooled with the furnace to obtain SiC / TaC ceramic powder.

[0078] Step 5: ZrC and polymer-converted SiC / TaC ceramic powders were mixed in a mass ratio of 7:3, and the mixed ceramic powders were mixed with polyvinyl alcohol solution, anhydrous ethanol and deionized water in a mass ratio of 4:4:1:1 in a ball mill for 4 hours to obtain a uniform ceramic slurry suspension.

[0079] Step 6: The ceramic suspension is fed into the nozzle of the spray granulation equipment through a peristaltic pump, and the inlet temperature and outlet temperature are controlled to be approximately 330° C. and 100° C., respectively, to obtain spherical ceramic powder.

[0080] Step 7: The granulated spherical powder is fed into the plasma jet through a powder feeder, and a ZrC-SiC / TaC coating containing polymer-derived nanocarbon is prepared on the surface of the SiC-C / C composite material using a supersonic plasma spraying device.

[0081] The surface temperature change of the sample during the ablation process was tested using an infrared thermometer. The maximum temperature obtained is recorded in Table 1. The mass change of the sample before and after ablation and the change in the thickness of the central area were calculated to obtain the mass and linear ablation rate of the sample. The specific performance of each sample is shown in Table 1.

[0082] Table 1 shows the ablation time, maximum surface temperature during ablation, mass and linear ablation rate of the samples in the examples listed in Table 1

[0083]

[0084] It can be seen from Table 1 that compared with Comparative Example 1, the surface temperature of Example 1 is reduced by about 200°C, and the mass and linear ablation rate are reduced by about 0.9 times and 0.8 times respectively. The surface temperature of the samples of Examples 2 to 5 is reduced by about 100 to 200°C compared with Comparative Example 1, and has a lower mass ablation rate. Among them, Example 2 has the weakest cooling effect due to the low content of DVB added, and the linear ablation rate is slightly larger. In Example 3, in which the DVB content is increased year-on-year, the cooling effect during the ablation process is more obvious due to the increased content of nanocarbon contained, and it has a lower mass and linear ablation rate.

[0085] In the design of composite materials prepared using the polymer-to-ceramic method, the molecular structure of the precursor directly influences the phase composition of the polymer-to-ceramic. After adding an organic carbon source containing unsaturated bonds, the carbon-containing branched groups in the synthesized single-source precursor gradually convert into nanocarbon materials during pyrolysis and high-temperature heat treatment. Due to the chemical reaction between the unsaturated organic carbon source in the precursor and polycarbosilane and tantalum chloride, the resulting composite ceramic after heat treatment contains polymer-derived nanocarbon uniformly dispersed at the nanometer level. This composite ceramic containing polymer-derived nanocarbon is then mixed with ZrC and coated using supersonic plasma spraying to produce a ZrC-based anti-ablation coating containing polymer-derived nanocarbon materials.

[0086] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Improvements and modifications that do not depart from the principles of the present invention should also be considered as the scope of protection of the present invention.

Claims

1. A method for preparing an anti-ablation ceramic coating containing polymer-derived nanocarbon, characterized in that A polymer-to-ceramic method is used to prepare a composite ceramic, and an anti-ablation ceramic coating is prepared using the composite ceramic; the composite ceramic contains uniformly dispersed nanocarbon materials, and the preparation steps are as follows: Step 1: Using a Schlenk apparatus, place a polymer precursor, a transition metal compound, an organic carbon source containing unsaturated bonds, and an organic solvent in a Schlenk flask. Under Ar atmosphere, react with magnetic stirring at 80-150°C for 2-12 hours. Remove the organic solvent under vacuum to obtain a single-source precursor powder. Step 2: The single-source precursor powder is placed in a tube furnace and, under Ar atmosphere protection, cross-linked, cured, cracked, and subjected to high-temperature heat treatment. The inorganicization of the organic carbon functional groups containing unsaturated bonds in the single-source precursor yields a composite ceramic powder rich in nanocarbon materials. The cross-linking curing temperature is 100-300°C; The cracking temperature is 900-1200°C; The heat treatment temperature is 1400~1900℃; The holding time during the cross-linking, curing, cracking and high-temperature heat treatment process is 2 to 5 hours; Step 3: ball-milling the composite ceramic powder containing polymer-derived nanocarbon, ZrC, polyvinyl alcohol solution, anhydrous ethanol, and deionized water to prepare a mixed slurry, spraying the slurry into a granulated form, and then spraying the slurry onto the surface of the substrate using a supersonic plasma spraying method to obtain an anti-ablation ceramic coating containing polymer-derived nanocarbon; In step 1, the polymer precursor is polycarbosilane, polynitrosilane, polysiloxane or polyborosilazane; The organic carbon source containing unsaturated bonds in step 1 is ferrocene; The organic solvent in step 1 comprises one or more of toluene, xylene, and furan; In step 3, the ratio of the composite ceramic powder containing polymer-derived nanocarbon, ZrC, polyvinyl alcohol solution, anhydrous ethanol and deionized water is 1-3:1-3:4:1:1; In step 3, the matrix material is graphite coated with a SiC coating, a C / C composite material, or a C / ultra-high temperature ceramic composite material.

2. The method for preparing the ablation-resistant ceramic coating containing polymer-derived nanocarbon according to claim 1, characterized in that: The heating rate of step 2 is 3-10°C / min.

3. An ablation-resistant ceramic coating prepared by the method of claim 1 or 2, characterized in that: An organic carbon source containing unsaturated bonds is added to the precursor, and a nanocarbon-rich composite ceramic is generated in situ during the inorganic transformation process, and the nanocarbon material is evenly distributed in the ceramic.

4. The ablation-resistant ceramic coating according to claim 3, characterized in that: An anti-ablation ceramic coating containing polymer-derived nanocarbon was prepared by ultra-high-speed plasma spraying, with the surface temperature reduced by 100~200℃, and the mass and linear ablation rate reduced by 0.9 times and 0.8 times, respectively.

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