Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-heating technology combined with bionic glass membrane synergistic oxygen resistance

Abstract

The application discloses a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-heating technology and combined with bionic glass film for synergistic oxygen resistance, and the coating comprises a base layer, a transition layer and a bionic glass layer. Compared with the prior art, the application has the advantages that the application overcomes the problems of existing ZrB2-SiC ceramic coating system, such as oxidation structural defect, high oxygen permeability, and the like. The application reduces oxidation activity and oxidation consumption, improves service temperature, has the advantages of strengthening oxidation protection effect and prolonging working life. After oxidation at 1700 DEG C for 100 min, the cumulative antioxidation protection efficiency is 99.809%, the carbon loss rate is 1.032%, and the application has the effect of stable oxygen resistance protection at 1700 DEG C.

Description

Technical Field

[0001] This invention relates to the field of protective coatings for carbon-based composite materials and their preparation technology, and particularly to a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. It can be used for oxidation and corrosion protection of carbon / carbon composite materials and their components in high-temperature environments. Especially when applied to the wings of aerospace vehicles, it exhibits stable high-temperature oxidation resistance in an aerobic environment at 1700℃. Background Technology

[0002] Carbon structural materials, urgently needed for the aerospace strategies of major countries worldwide, are valuable due to their sp... 2 Hybrid orbitals, exhibiting extremely anisotropic crystalline combinations, are reinforced through various composite methods, resulting in carbon structural materials possessing properties such as high melting point, low density, high-temperature strength, and thermal shock resistance. Therefore, they are widely considered suitable high-temperature thermal structural materials for manufacturing engineering components such as hypersonic vehicles. However, as carbon-based materials, their extreme sensitivity to oxygen is a significant factor limiting their production. When the operating temperature of engineering components made from carbon structural materials exceeds 370℃, the carbon structural materials will oxidize to produce CO or CO2. When the temperature exceeds 600℃, the oxidation phenomenon becomes even more intense, posing a potential safety hazard to the engineering components.

[0003] Among ultra-high temperature ceramic coating materials, the ZrB2-SiC ceramic system is superior. During oxidation, SiC can react to generate SiO2 at high temperature, and ZrB2 can form ZrO2 at high temperature. The combination of various oxidation products forms a Zr-B-Si-O composite glass film, which fills the coating pores and effectively hinders oxygen penetration. For example, Li T et al. (Li T, Zhang Y, Lv J, et al. Eliminated siliconization corrosion and improved oxidation resistances of SiC-Sicoated C / C composites via a ZrB2-rich transition layer[J]. Corrosion Science, 2022, 195:109986.) disclosed a ZrB2-SiC-Si ternary phase oxygen barrier coating and its preparation method, and pointed out that the mass loss of the coating of this ternary phase ceramic material under static oxidation protection at 1500℃ is only 0.09%. Li L et al. (Li L, Yu Y, Yang J, et al. A ZrB2-SiC(Al) coating with improved oxidation resistance for C / C composites: Design, experimental verification and oxidation mechanism[J]. Journal of the European Ceramic Society, 2024, 44(6):3487-3500.) prepared ZrB2-SiC(Al) coatings using spark plasma sintering. By optimizing the alumina doping amount, ZrB2-SiC(Al) coatings with excellent oxidation resistance can be obtained. Al doping can promote the dissolution of Zr atoms in silicon dioxide, enhance Si-O bonds, thereby promoting changes in the glass structure and improving oxidation resistance.

[0004] However, in high-temperature, oxygen-rich environments, the vapor pressure of B2O3, an oxidation product of ZrB2, gradually increases, leading to its rapid evaporation and loosening of the coating structure, thus increasing the diffusion path of oxygen within the coating. Furthermore, above 1625℃, the oxidation mode of SiC in oxygen-rich environments changes from passive to active oxidation, generating SiO gas, which further damages the oxygen-barrier structure of the coating. Given the easily oxidized nature of carbon materials, the oxygen-barrier structure and the stability and integrity of the coating glass film are crucial for suppressing oxygen permeation. -

[0005] This invention constructs a biomimetic glass membrane based on the self-healing repair mechanism of the plant *Dracaena sanderiana*. A low-energy self-exothermic technology is used to prepare the biomimetic glass membrane on a Y2O3-ZrSi2-ZrB2-SiC coating for synergistic oxygen barrier properties. By constructing a unique coating structure, the synergistic effect of the self-generated film within the internal coating combined with the biomimetic glass membrane reduces the loss of the internally generated film. Due to the high dispersion of oxides in the biomimetic glass membrane, defects such as cracks and pores generated on the surface can be effectively healed during oxidation, inhibiting the dynamic evolution of the coating structure and hindering oxygen permeability. Simultaneously, the extended heat treatment time improves the bonding between the coating and the biomimetic glass membrane, reduces the volatility of the glass membrane, and enhances the stability of the oxygen barrier structure. Compared with existing ZrB2-SiC-based oxygen barrier coatings, the high-temperature oxidation resistance temperature is increased by approximately 100–400℃. The biomimetic glass membrane with a film-forming treatment of 360 min has a final oxygen permeability of 0.600% and an average oxygen permeability of 1.047%, demonstrating a significant antioxidant effect. The structural factor and the inerting factor for oxygen barrier properties were 1.446% and 2.065%, respectively. Summary of the Invention

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] A Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier is characterized by comprising a substrate layer, a transition layer, and a biomimetic glass layer. The substrate layer comprises a graphite-based material, the transition layer is a Y2O3-ZrSi2-ZrB2-SiC multiphase coating, and the biomimetic glass layer comprises a Zr-Y-Si-O glass layer. The substrate layer and the biomimetic glass layer are respectively disposed on the innermost and outermost sides. The transition layer is disposed between the substrate layer and the biomimetic glass layer.

[0008] In this invention, Y₂O₃ and ZrSi₂, which can improve the density of the coating and have high oxidation resistance, are selected as doping additives to compensate for the defects of ZrB₂-SiC coatings during high-temperature oxidation. Y₂O₃ promotes the formation of more Y₂SiO₅ and Y₂Si₂O₇ in the glass film, and due to its pinning effect, a Zr-B-Si-OY multiphase glass layer is formed. Meanwhile, Y… 3+ As high-field-strength ions, they have a significant accumulation effect on the glass network structure, increasing the overall viscosity of the glass layer and inhibiting the volatilization of SiO2 at high temperatures. The addition of ZrSi2 promotes the formation of ZrSiO4, enhancing the stability of the transition layer. These nanocrystalline particles embedded in the transition layer force the oxygen diffusion path to deflect when in contact with oxygen, thereby reducing oxygen erosion of the interior, promoting oxidation inhibition, and reducing the oxygen diffusion rate.

[0009] Among them, the Zr-YO nanopowder prepared by low-energy self-exothermic combustion synthesis of the present invention, Y 3+ The ionic radius (0.092 nm) is only slightly larger than that of Zr. 4+ The ionic radius (0.082 nm) of Y during the synthesis process 3+ Replaced Zr 4+ At its position within the unit cell, a stable fluorite structure forms, resulting in a solid solution of Zr. 0.935 Y 0.065 O 1.968 Simultaneously, lattice distortion occurs, resulting in a greater ability to deflect oxygen during diffusion. The biomimetic glass film of this invention exhibits high dispersion of oxides ZrSiO4 and Y2Si2O7, which can effectively heal surface defects such as cracks and pores during oxidation, inhibiting the dynamic evolution of the coating structure and effectively hindering oxygen penetration. Furthermore, the extended heat treatment time improves the bonding between the coating and the biomimetic glass film, reduces the volatility of the glass film, and enhances the stability of the oxygen barrier structure. The high crystallinity of Y2Si2O7 effectively deflects the diffusion direction of oxygen, reducing oxygen erosion of the coating interior, thereby achieving antioxidant protection for the carbon matrix.

[0010] Specifically, the Y2O3 doping content in the transition layer Y2O3-ZrSi2-ZrB2-SiC is 0.5-3.5 mol%, the ZrSi2 doping content is 1-4.0 mol%, and the balance is zirconium boride and silicon carbide main phase ceramic; the biomimetic glass layer is a Zr-Y-Si-O material.

[0011] Specifically, the thickness of the transition layer is 1000–4000 μm, and the thickness of the biomimetic glass layer is 500–1500 μm.

[0012] Furthermore, this invention also provides a method for preparing a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier, comprising:

[0013] Step 1: Mix the solution. Weigh 5.00-7.00g of Y(NO3)3·6H2O and dissolve it in 80-100ml of deionized water to obtain an aqueous solution of yttrium. Then, weigh 3.00-5.00g of urea (CH4N2O) and add it to the yttrium nitrate solution. Stir well to ensure that the urea is completely dissolved.

[0014] Step 2: Low-energy self-exothermic combustion synthesis of Y₂O₃. The homogeneously mixed solution from Step 1 is placed in a crucible and then placed in an electric furnace. The solution is rapidly heated to approximately 150°C to 200°C using triggered microwave preheating. During this process, water evaporates, the solution gradually concentrates, urea begins to decompose and react with yttrium nitrate, releasing heat and initiating a combustion reaction. In the combustion reaction, urea acts as a reducing agent, converting into CO₂ and water vapor. The heat released after combustion causes the reaction to heat up rapidly, ultimately forming Y₂O₃ powder. The preparation reaction formula is as follows:

[0015]

[0016] Step 3: Mix the solution. Weigh 6.00-8.00g of Zr(NO3)4·5H2O, 4.00-6.00g of Y(NO3)3·6H2O, and 3.00-5.00g of urea (CH4N2O) into a beaker, add 80-100ml of deionized water to obtain an aqueous solution of zirconium and yttrium. Place the beaker on a magnetic stirrer and mix at 200r / min for 30min.

[0017] Step 4: Low-energy self-exothermic combustion synthesis of Zr-YO solid solution powder. The homogenized solution from Step 3 is placed in a crucible and then in an electric furnace. The solution is rapidly heated to approximately 650–700°C using trigger-type microwave preheating. During this process, water evaporates, the solution gradually concentrates, and urea begins to decompose and react with yttrium nitrate and zirconium nitrate, releasing heat and initiating a combustion reaction. The heat released by the combustion reaction causes the reaction temperature to rise rapidly, ultimately forming Zr-YO solid solution powder.

[0018] Step 5: Raw material mixing. Zirconium powder, boron powder, silicon powder and yttrium oxide are used as raw materials and mixed in a volume ratio of 6:3:7:1 to 6:5:8:1.5. The mixture is then ball-milled at 350 r / min for 5 hours to obtain a mixed powder.

[0019] Step 6: Self-propagating combustion synthesis to prepare powder: The composite powder from step 5 is pressed into blocks with a diameter of 15 mm and a height of 6 mm using a tablet press, and then synthesized into powder through low-temperature exothermic synthesis in a self-propagating furnace under an argon atmosphere with a pressure of 5 MPa.

[0020] Step 7: Coating sintering: The self-propagating powder is wrapped around the graphite matrix and filled into a graphite mold with a diameter of 20 mm. Plasma spark sintering is carried out in a vacuum environment (-99.5 MPa) to prepare a ZrSi2 combined with Y2O3 modified ZrB2-SiC coating.

[0021] Step 8: Film formation treatment: Mix the Zr-YO nanopowder obtained in step 4 with silica sol to form a colloid with a slurry ratio of 1:6. Apply the colloid to the coating surface and place it in a muffle furnace at 1200℃ for film formation treatment to form a glass film.

[0022] In the above method, the chemical composition of the modified coating in the biomimetic biofilm combined with the rare earth-doped binary silicide modified gradient oxygen barrier coating is: Y2O3-ZrSi2-ZrB2-SiC; the composition of the biomimetic glass layer is: Zr-Y-Si-O glass layer.

[0023] Specifically, in step 1, the molar ratio of Y(NO3)3·6H2O and urea (CH4N2O) is in the range of 3:7 to 4:9.

[0024] Specifically, in step 2, the heating rate for synthesizing nano-Y2O3 powder through low-energy self-exothermic combustion is 100℃ / min, and the heating atmosphere is in an oxygen-rich environment.

[0025] Specifically, in step 3, the molar ratio of Zr(NO3)4·5H2O, Y(NO3)3·6H2O, and urea (CH4N2O) ranges from 3:2:5 to 4:3:16. Fuel ratio: Since the fuel is in a state of residual state, it needs to obtain O2 from the air to act as a combustion aid and ensure that the fuel burns completely.

[0026] Specifically, in step 4, the microwave preheating rate of the electric furnace is 150°C / min. The heating temperature fluctuates by ±15%, such as... Figure 3

[0027] As shown, the powder synthesized using low-energy exothermic synthesis has a grain size of approximately 70–75 nm, and ZrO2 is stabilized in a tetragonal crystal form by Y2O3. The chemical reactions that occur are as follows:

[0028]

[0029] Specifically, in step 6, the preheating temperature of the self-propagating combustion synthesis furnace is 750-800°C, and tungsten wire with a diameter of 1.5 mm is used for ignition.

[0030] Specifically, in step 7, the temperature range for preparing the Y2O3-ZrSi2-ZrB2-SiC coating by plasma spark sintering is 1450–1500 °C.

[0031] The advantages of this invention compared to the prior art are:

[0032] 1. This invention utilizes the self-healing repair mechanism of the dragon's blood tree and employs low-energy self-exothermic technology to prepare a composite ceramic coating with a Y2O3-ZrSi2-ZrB2-SiC transition layer and an outer biomimetic glass film for synergistic oxygen barrier properties. The outer biomimetic glass layer, through structural oxygen barrier, reduces internal oxidation losses in the substrate and transition layer structures, decreases oxidation activity and consumption, and improves oxygen barrier quality. It also effectively avoids the problem of porous coating structure evolution caused by the inherent high activity of transition metal borides, which exacerbates oxidation loss and leads to failure. The transition layer leverages the characteristics of rare-earth oxide doped binary silicides to promote sintering density and complex film formation, offering advantages in enhancing coating structure densification and inhibiting oxygen diffusion, achieving multiple synergistic oxygen barrier effects.

[0033] 2. The outer biomimetic glass layer powder of this invention is synthesized using low-energy self-exothermic triggered microwave preheating combustion. Microwave heating rapidly raises the solution temperature to a preheating temperature of 550°C, bringing it close to the combustion reaction trigger temperature of 600°C. This significantly shortens the preheating time. Compared to traditional commercial powders, the synthesized powder has a finer particle size, and the combustion reaction is completed within 1-2 minutes, with an energy utilization rate as high as 98.97%. The combustion reaction is fully exothermic, reducing external energy input, and the synthesis process... 3+ Replaced Zr 4+ At its position within the unit cell, a stable fluorite structure forms, resulting in a solid solution of Zr. 0.935 Y 0.065 O 1.968 Simultaneously, lattice distortion occurs, resulting in a greater ability to deflect O during the diffusion process. Furthermore, most of the ZrO2 is stabilized into a tetragonal crystal form by Y2O3, reducing stress accumulation during the phase transformation process.

[0034] 3. As an effective high-temperature oxygen barrier coating for carbon / carbon composite materials, this invention presents a method for preparing a composite ceramic coating combining a Y2O3-ZrSi2-ZrB2-SiC coating with a biomimetic glass film for synergistic oxygen barrier, based on low-energy self-exothermic technology. This method overcomes the oxidation and porosity problem that occurs in ZrB2-SiC coatings above 1700℃, thereby increasing the service temperature of the ZrB2-SiC coating and enhancing its oxidation protection effect and service life. Furthermore, compared with traditional multilayer coating preparation processes (such as plasma spraying and spark plasma sintering), this film-forming process is simpler, more efficient, and reduces energy waste. Simultaneously, after film formation, the dispersed distribution of Y2Si2O7 and ZrSiO4 particles increases the viscosity of the glass film, suppressing its volatilization tendency at high temperatures. This effectively heals surface defects such as cracks and pores, inhibits the dynamic evolution of the coating structure, and hinders oxygen permeability. It also overcomes the problems of high sintering temperature and energy waste in conventional SPS preparation methods. Under the condition of oxidation at 1700℃ for 100 min, the cumulative antioxidant protection efficiency is as high as 99.997%, and the carbon loss rate is only 1.032%, showing excellent high-temperature oxidation resistance.

[0035] 4. This invention utilizes a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier properties. The high-temperature stable oxygen barrier protection temperature of the graphite material can be increased to 1700℃, which is approximately 100–400℃ higher than existing ZrB2-SiC-based oxygen barrier coatings. The biomimetic glass film, after 100 minutes of film formation treatment, exhibits a final oxygen permeability of 0.600% and an average oxygen permeability of 1.047%. It also demonstrates the lowest structural factor and inertization factor values ​​for oxygen barrier performance, at 1.446% and 2.065%, respectively, exhibiting a significant antioxidant enhancement effect. Furthermore, by employing self-propagating combustion synthesis, the coating preparation temperature can be reduced to a maximum of 1450℃. This is approximately 450℃ lower than the sintering temperature of existing conventional SPS preparation methods, significantly saving energy consumption and reducing the difficulty of product preparation.

[0036] In summary, this invention overcomes the problems of existing ZrB2-SiC binary ceramic coatings, such as high sintering temperature, high material preparation difficulty, energy waste, high-temperature oxidation porosity, and low oxidation protection temperature. It offers advantages such as lowering the sintering temperature, simplifying material preparation, saving energy consumption, improving coating density, reducing internal defects, reducing oxidation activity and consumption, increasing service temperature, enhancing oxidation protection effect, and extending service life, achieving stable oxygen barrier protection at high temperatures up to 1700℃. Attached Figure Description

[0037] Figure 1 This is a process flow diagram of the present invention.

[0038] Figure 2 This is the XRD diffraction pattern of Zr-YO powder synthesized using low-energy self-exothermic combustion in this invention.

[0039] Figure 3 This is a histogram showing the grain size frequency distribution of Zr-YO powder synthesized using low-energy self-exothermic combustion in this invention.

[0040] Figure 4 (a) is a HAADF dark field image of Zr-YO powder synthesized by low-energy self-exothermic combustion in this invention.

[0041] Figure 4 (b) is a low-magnification TEM image of Zr-YO powder synthesized by low-energy self-exothermic combustion in this invention.

[0042] Figure 4 (c) is the corresponding EDS energy spectrum of Zr-YO powder synthesized by low-energy self-exothermic combustion in this invention.

[0043] Figure 4 (d) is a high-magnification TEM image of Zr-YO powder synthesized by low-energy self-exothermic combustion in this invention.

[0044] Figure 5 The XRD diffraction patterns are those of the glass films obtained in Examples 3, 7 and Comparative Example 1 of this invention.

[0045] Figure 6 (a)-(c) are low-magnification BSE-SEM images of the cross sections of each coating before oxidation after film formation treatment in Examples 3, 7 and Comparative Example 1 of the present invention.

[0046] Figure 6 (a1)-(c1) BSE-SEM images of the coating-substrate interface before oxidation of each coating after film formation treatment in Examples 3, 7 and Comparative Example 1 of the present invention.

[0047] Figure 6 (a2)-(c2) High-magnification BSE-SEM images of the cross sections of each coating before oxidation after film formation treatment in Examples 3, 7 and Comparative Example 1 of the present invention.

[0048] Figure 6 (a3)-(c3) are the EDS energy spectra of O element corresponding to the coating cross sections before oxidation of each coating after film formation treatment in Examples 3, 7 and Comparative Example 1 of the present invention.

[0049] Figure 7(a)-(c) are low-magnification BSE-SEM microstructure images of the cross sections of each coating after film formation treatment and oxidation at 1700℃ for 100 min in Examples 3, 7 and Comparative Example 1 of the present invention.

[0050] Figure 7 (a1)-(c1) are BSE-SEM images of the bonding between the coating and the substrate after film formation treatment and oxidation at 1700℃ for 100 min in Examples 3, 7 and Comparative Example 1 of the present invention.

[0051] Figure 7 (a2)-(c2) are high-magnification BSE-SEM images of the cross sections of each coating after film formation treatment and oxidation at 1700℃ for 100 min in Examples 3, 7 and Comparative Example 1 of the present invention.

[0052] Figure 7 (a3)-(c3) are the EDS energy spectra of the O element in each cross section of the coating after film formation treatment and oxidation at 1700℃ for 100 min in Examples 3, 7 and Comparative Example 1 of the present invention.

[0053] Figure 8 The oxygen permeability curves of each coating obtained after film formation treatment in Examples 1, 3, 5, 7, Comparative Examples 1, 2, and 3 of the present invention are obtained during the oxidation process at 1700°C for 100 min.

[0054] Figure 9 The cumulative antioxidant protection efficiency curves of each coating after film formation treatment obtained in Examples 1, 3, 5, 7, Comparative Examples 1, 2, and 3 of the present invention are obtained during oxidation at 1700°C for 100 min. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. It should be emphasized that the embodiments described are only some implementations of the present invention and do not represent all implementations. The components shown in the accompanying drawings can be configured and designed differently according to actual needs. The low-energy self-exothermic combustion synthesis preparation of Y2O3 powder and Zr-YO powder described in the embodiments and comparative examples includes the following steps:

[0056] Step 1: Low-energy exothermic combustion synthesis to prepare Y₂O₃ powder. Weigh 5.00–7.00 g of Y(NO₃)₃·6H₂O and dissolve it in 80–100 ml of deionized water. Weigh 3.00–5.00 g of urea (CH₄N₂O) and add it to the yttrium nitrate solution, stirring until homogeneous. Preheat the solution rapidly to approximately 150°C to 200°C using a triggered microwave preheating method. The heat released by the combustion reaction causes the reaction to heat up rapidly, ultimately forming Y₂O₃ powder.

[0057] Step 2: Low-energy exothermic combustion synthesis to prepare Zr-YO powder. Weigh 6.00–8.00 g of Zr(NO3)4·5H2O, 4.00–6.00 g of Y(NO3)3·6H2O, and 3.00–5.00 g of urea (CH4N2O) into a beaker, add 80–100 ml of deionized water, and stir until homogeneous. Preheat the solution rapidly to approximately 650–700 °C using a triggered microwave preheating method. The heat released during the combustion reaction causes the reaction to heat up rapidly, ultimately forming Zr-YO solid solution powder.

[0058] Figure 2 The figure shows the phase structure of Zr-YO solid solution powder synthesized by low-energy self-exothermic synthesis. Zr was detected in the powder. 0.935 Y 0.065 O 1.968 The ZrO2 phase is monoclinic. Each phase exhibits sharp diffraction peaks, indicating good crystallinity. The grain size frequency distribution histogram of the low-energy, self-exothermic synthesized Zr-YO solid solution powder is shown below. Figure 3 As shown, the synthesized Zr-YO solid solution powder has a grain size of approximately 70–75 nm, and ZrO2 is stabilized in a tetragonal crystal form by Y2O3. High-resolution transmission electron microscopy (HRTEM) of the low-energy, self-exothermic synthesis of Zr-YO solid solution powder is shown in the figure. Figure 4 As shown, the synthesized powder has distinct overall particles with a polygonal regular block shape. The particles are relatively dispersed, and the Zr, Y and O elements in the synthesized powder are relatively uniformly dispersed with clear lattice stripes, indicating that the product has good crystallinity. The Zr, Y and O elements account for 47.39%, 1.83% and 50.78% respectively.

[0059] Example 1:

[0060] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 0.5 mol%, and the ZrSi₂ doping content is 1.0 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0061] This embodiment uses graphite as a substrate, and the oxygen-barrier coating consists of a substrate layer, a Y2O3-ZrSi2-modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 0.5 mol% and a ZrSi2 doping content of 1.0 mol%. The oxygen-barrier coating has a thickness of 4000 μm, and the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0062] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion synthesis above are used as raw materials, mixed in a volume ratio of 6:3:7:1 to 6:5:8:1.5, and the powder is synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0063] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and ball-milled with 40% SiC added by volume. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0064] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0065] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. In this embodiment, Y2O3 powder is prepared by low-energy self-exothermic combustion synthesis, Zr-YO powder is prepared by low-energy self-exothermic synthesis, composite powder is prepared by self-propagating combustion synthesis, the coating is sintered by plasma spark sintering, and finally, a biomimetic glass film is formed. The oxidation protection efficiency at 1700℃ is shown in Table 1. As can be seen from the table, this embodiment is superior to Comparative Examples 1, 2, and 3 in terms of oxidation protection efficiency. Figure 8 , Figure 9 The oxygen permeability curve and cumulative protective efficiency of the coating after oxidation at 1700℃ for 100 min are shown. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0066] Example 2:

[0067] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 1.0 mol%, and the ZrSi₂ doping content is 1.5 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0068] This embodiment uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer, a Y2O3-ZrSi2 modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 1.0 mol% and a ZrSi2 doping content of 1.5 mol%. The oxygen barrier coating has a thickness of 4000 μm, and the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0069] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion synthesis above are used as raw materials, mixed in a volume ratio of 6:5:7:1.5 to 6:5:8:2, and synthesized into powder by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0070] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and ball-milled with 40% SiC added by volume. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0071] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0072] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. In this embodiment, Y2O3 powder is prepared by low-energy self-exothermic combustion synthesis, Zr-YO powder is prepared by low-energy self-exothermic synthesis, composite powder is prepared by self-propagating combustion synthesis, the coating is sintered by plasma spark sintering, and finally, a biomimetic glass film is formed. The oxidation protection efficiency at 1700℃ is shown in Table 1. As can be seen from the table, this embodiment is superior to comparative examples 1, 2, and 3 in terms of oxidation protection efficiency. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0073] Example 3:

[0074] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 1.5 mol%, and the ZrSi₂ doping content is 2.0 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0075] This embodiment uses graphite as a substrate, and the oxygen-barrier coating consists of a substrate layer, a Y2O3-ZrSi2-modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 1.5 mol% and a ZrSi2 doping content of 2.0 mol%. The oxygen-barrier coating has a thickness of 4000 μm; the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0076] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion were used as raw materials, mixed in a volume ratio of 7:5:7:2 to 7:5.5:7:2.5, and synthesized into powder by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0077] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and ball-milled with 40% SiC added by volume. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0078] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0079] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. The phase structure of the glass film after film formation treatment at 1200℃ for 100 min is as follows. Figure 5As shown, after the film formation treatment, the surface is mainly composed of oxidation products ZrO2, ZrSiO4, Y2Si2O7, and unreacted ZrB2 and SiC. The diffraction peaks of each phase are sharp, indicating good crystallinity. The surface morphology and cross-sectional morphology of the composite coating before oxidation are shown in the figure. Figure 6 As shown, the oxygen after heat treatment is mainly distributed on the coating surface and is an oxide of the biomimetic glass film. The closer to the carbon matrix, the lower the oxygen content. This indicates that the film-forming treatment did not have a significant impact on the interior of the coating. The surface morphology and cross-sectional morphology of the composite coating after oxidation at 1700℃ for 100 min are shown in the figure. Figure 7 As shown, a distinct oxide layer with a thickness of approximately 407 μm was observed, indicating that the introduction of biomimetic glass resulted in a 52.3% reduction in oxide layer thickness compared to Comparative Example 1. The oxidation protection efficiency at 1700 °C is shown in Table 1. The table shows that this embodiment demonstrates superior oxidation protection efficiency compared to Comparative Examples 1, 2, and 3. Figure 8 , Figure 9 The oxygen permeability curve and cumulative protective efficiency of the coating after oxidation at 1700℃ for 100 min are shown. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0080] Example 4:

[0081] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 2.0 mol%, and the ZrSi₂ doping content is 2.5 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0082] This embodiment uses graphite as a substrate, and the oxygen-barrier coating consists of a substrate layer, a Y2O3-ZrSi2 modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 2.0 mol% and a ZrSi2 doping content of 2.5 mol%. The oxygen-barrier coating has a thickness of 4000 μm; the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0083] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion synthesis above are used as raw materials, mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5, and synthesized into powder by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0084] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and ball-milled with 40% SiC added by volume. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0085] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0086] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. In this embodiment, Y2O3 powder is prepared by low-energy self-exothermic combustion synthesis, Zr-YO powder is prepared by low-energy self-exothermic synthesis, composite powder is prepared by self-propagating combustion synthesis, the coating is sintered by plasma spark sintering, and finally, a biomimetic glass film is formed. The oxidation protection efficiency at 1700℃ is shown in Table 1. As can be seen from the table, this embodiment is superior to comparative examples 1, 2, and 3 in terms of oxidation protection efficiency. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0087] Example 5:

[0088] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 2.5 mol%, and the ZrSi₂ doping content is 3.0 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0089] This embodiment uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer, a Y2O3-ZrSi2 modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 2.5 mol% and a ZrSi2 doping content of 3.0 mol%. The oxygen barrier coating has a thickness of 4000 μm; the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0090] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion were used as raw materials, mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5. The powder was synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0091] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and then ball-milled with 40% SiC added by volume at a ball mill speed of 350 r / min for 5 h. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0092] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0093] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. In this embodiment, Y2O3 powder is prepared by low-energy self-exothermic combustion synthesis, Zr-YO powder is prepared by low-energy self-exothermic synthesis, composite powder is prepared by self-propagating combustion synthesis, the coating is sintered by plasma spark sintering, and finally, a biomimetic glass film is formed. The oxidation protection efficiency at 1700℃ is shown in Table 1. As can be seen from the table, this embodiment is superior to Comparative Examples 1, 2, and 3 in terms of oxidation protection efficiency. Figure 8 , Figure 9 The oxygen permeability curve and cumulative protective efficiency of the coating after oxidation at 1700℃ for 100 min are shown. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0094] Example 6:

[0095] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 3.0 mol%, and the ZrSi₂ doping content is 3.5 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0096] This embodiment uses graphite as a substrate, and the oxygen-barrier coating consists of a substrate layer, a Y2O3-ZrSi2 modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 3.0 mol% and a ZrSi2 doping content of 3.5 mol%. The oxygen-barrier coating has a thickness of 4000 μm; the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0097] Step 1: Low-energy self-exothermic combustion synthesis to prepare composite powder. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion as raw materials are mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5, and the powder is synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0098] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and ball-milled with 40% SiC added by volume. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0099] Step 3: Film formation treatment of the biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid, and the colloid is brushed onto the coating surface. It is dried in a constant temperature drying oven at 50℃ for 30 seconds; the composite coating is then placed in a high-temperature resistance furnace for film formation treatment at 1200℃ for 100 minutes.

[0100] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. In this embodiment, Y2O3 powder is prepared by low-energy self-exothermic combustion synthesis, Zr-YO powder is prepared by low-energy self-exothermic synthesis, composite powder is prepared by self-propagating combustion synthesis, the coating is sintered by plasma spark sintering, and finally, a biomimetic glass film is formed. The oxidation protection efficiency at 1700℃ is shown in Table 1. As can be seen from the table, this embodiment is superior to comparative examples 1, 2, and 3 in terms of oxidation protection efficiency. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0101] Example 7:

[0102] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 3.5 mol%, and the ZrSi₂ doping content is 4.0 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1200℃, and the heat treatment time is 100 min.

[0103] This embodiment uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer, a Y2O3-ZrSi2 modified ZrB2-SiC coating, and a biomimetic glass film layer. The Y2O3-ZrSi2-ZrB2-SiC layer has a Y2O3 doping content of 3.5 mol% and a ZrSi2 doping content of 4.0 mol%. The oxygen barrier coating has a thickness of 4000 μm; the biomimetic glass film has a thickness of 1500 μm. The specific steps are as follows:

[0104] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by combustion synthesis of the above solution were used as raw materials, mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5. The powder was synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0105] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and ball-milled with 40% SiC added by volume. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0106] Step 3: Film formation treatment of the biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid, and the colloid is brushed onto the coating surface. It is dried in a constant temperature drying oven at 50℃ for 30 seconds; the composite coating is then placed in a high-temperature resistance furnace for film formation treatment at 1200℃ for 100 minutes.

[0107] This embodiment provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. The phase structure of the glass film after film formation treatment at 1200℃ for 100 min is as follows. Figure 5 As shown, after the film formation treatment, the surface is mainly composed of oxidation products ZrO2, ZrSiO4, Y2Si2O7, and unreacted ZrB2 and SiC. The diffraction peaks of each phase are sharp, indicating good crystallinity. The surface morphology and cross-sectional morphology of the composite coating before oxidation are shown in the figure. Figure 6As shown, the oxygen after heat treatment is mainly distributed on the coating surface and is an oxide of the biomimetic glass film; the closer to the carbon matrix, the lower the oxygen content. The surface morphology and cross-sectional morphology of the composite coating after oxidation at 1700℃ for 100 min are shown below. Figure 7 As shown, a distinct oxide layer with a thickness of approximately 26 μm was observed, indicating that the introduction of biomimetic glass resulted in a 94.3% reduction in oxide layer thickness compared to Comparative Example 1. The oxidation protection efficiency at 1700℃ is shown in Table 1. The table shows that this embodiment demonstrates superior oxidation protection efficiency compared to Comparative Examples 1, 2, and 3. Figure 8 , Figure 9 The oxygen permeability curve and cumulative protective efficiency of the coating after oxidation at 1700℃ for 100 min are shown. The results indicate that the coating preparation method described in this embodiment effectively improves the oxidation resistance of the coating.

[0108] Comparative Example 1:

[0109] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 2.5 mol%, and the ZrSi₂ doping content is 3.0 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1100℃, and the heat treatment time is 100 min.

[0110] This comparative example uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer and a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating. The Y₂O₃ doping content in the Y₂O₃-ZrSi₂-ZrB₂-SiC layer is 2.5 mol%, the ZrSi₂ doping content is 3.0 mol%, and the thickness of the oxygen barrier coating is 4000 μm. The specific steps are as follows:

[0111] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion were used as raw materials, mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5. The powder was synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0112] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and then ball-milled with 40% SiC added by volume at a ball mill speed of 350 r / min for 5 h. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0113] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis above is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is placed in a high temperature resistance furnace for film formation treatment. The heat treatment temperature is 1100℃ and the heat treatment time is 100min.

[0114] This comparative example provides a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with a biomimetic glass film for synergistic oxygen barrier. The phase structure of the glass film after heat treatment at 1100℃ for 100 min is as follows. Figure 4 As shown, after the film formation treatment, the surface is mainly composed of oxidation products ZrO2, ZrSiO4, Y2Si2O7, and unreacted ZrB2 and SiC. The diffraction peaks of each phase are sharp, indicating good crystallinity. The surface morphology and cross-sectional morphology of the composite coating before oxidation are shown in the figure. Figure 6 As shown, after heat treatment, oxygen is mainly distributed on the coating surface, and the oxygen content decreases closer to the carbon matrix. The cross-sectional morphology of the composite coating surface after oxidation at 1700℃ for 100 min is shown in the figure. Figure 7 As shown, a distinct oxide layer appears, with a thickness of approximately 459 μm.

[0115] The oxidation protection efficiency at 1700℃ is shown in Table 1. Figure 8 , Figure 9 The oxygen permeability curve and cumulative protection efficiency of the coating after oxidation at 1700℃ for 100 min are shown. The results indicate that, compared with Example 5, the oxygen barrier effect at 1700℃ is significantly inferior in terms of oxidation protection efficiency. This demonstrates the advantages and necessity of the film-forming heat treatment process with a temperature of 1200℃ and a time of 100 min in this invention in improving the oxidation protection effect of the coating.

[0116] Comparative Example 2:

[0117] Using graphite as a substrate, an oxygen-barrier coating was constructed consisting of a substrate layer and a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, without employing a biomimetic film formation treatment. The Y₂O₃ doping content was 0.5 mol%, and the ZrSi₂ doping content was 1.0 mol%. The sintering temperature was 1500℃, the holding time was 5 min, and the sintering pressure was 30 MPa. The film formation heat treatment temperature was 1200℃, and the heat treatment time was 100 min.

[0118] This comparative example uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer and a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating. The Y₂O₃ doping content in the Y₂O₃-ZrSi₂-ZrB₂-SiC layer is 0.5 mol%, and the ZrSi₂ doping content is 1.0 mol%. No biomimetic film formation treatment was used, and the thickness of the oxygen barrier coating is 4000 μm. The specific steps are as follows:

[0119] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion were used as raw materials, mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5. The powder was synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0120] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and then ball-milled with 40% SiC added by volume at a ball mill speed of 350 r / min for 5 h. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0121] Step 3: Place the composite coating prepared in Step 2 into a high-temperature resistance furnace for film formation treatment. The heat treatment temperature is 1200℃ and the heat treatment time is 100min.

[0122] This comparative example presents an oxygen barrier coating constructed without employing a biomimetic film structure design, using graphite as a substrate and consisting of a "substrate layer + Y2O3-ZrSi2 modified ZrB2-SiC coating". The oxidation protection efficiency at 1700℃ is shown in Table 1. Figure 8 , Figure 9 The oxygen permeability curve and cumulative protection efficiency of this coating after oxidation at 1700℃ for 100 min are shown. The results indicate that, compared with Example 5, the oxygen barrier effect at 1700℃ is significantly inferior in terms of oxidation protection efficiency, demonstrating the advantages and necessity of using a structure with a substrate layer, a self-grown glass layer, and a biomimetic glass layer in this invention to improve the oxidation protection effect of the oxygen barrier coating.

[0123] Comparative Example 3:

[0124] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃ doping content is 4.0 mol%, and the ZrSi₂ doping content is 4.5 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1100℃, and the heat treatment time is 100 min.

[0125] This comparative example uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃-ZrSi₂-ZrB₂-SiC layer has a Y₂O₃ doping content of 4.0 mol% and a ZrSi₂ doping content of 4.5 mol%, and the oxygen barrier coating thickness is 4000 μm. The specific steps are as follows:

[0126] Step 1: Preparation of composite powder by self-propagating combustion synthesis. Zirconium powder, boron powder, silicon powder, and yttrium oxide prepared by microwave preheating combustion were used as raw materials, mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5. The powder was synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0127] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and then ball-milled with 40% SiC added by volume at a ball mill speed of 350 r / min for 5 h. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0128] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0129] The oxidation protection efficiency at 1700℃ is shown in Table 1. Figure 8 , Figure 9 The oxygen permeability curves and cumulative protection efficiency of this coating after oxidation at 1700℃ for 100 min are shown. The results indicate that, compared with Examples 1-7, the oxygen barrier effect at 1700℃ is significantly inferior in terms of oxidation protection efficiency, demonstrating the advantages and necessity of using a structure with a substrate layer, a self-grown glass layer, and a biomimetic glass layer in this invention to improve the oxidation protection effect of the oxygen barrier coating.

[0130] Comparative Example 4:

[0131] An oxygen-barrier coating is constructed using graphite as a substrate, consisting of a substrate layer, a commercial Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The commercial Y₂O₃ doping content is 3.0 mol%, and the ZrSi₂ doping content is 3.5 mol%. The sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa. The film-forming heat treatment temperature is 1100℃, and the heat treatment time is 100 min.

[0132] This comparative example uses graphite as a substrate, and the oxygen barrier coating consists of a substrate layer, a Y₂O₃-ZrSi₂ modified ZrB₂-SiC coating, and a biomimetic film-forming glass layer. The Y₂O₃-ZrSi₂-ZrB₂-SiC layer contains 3.0 mol% commercially available Y₂O₃ and 3.5 mol% ZrSi₂, and the oxygen barrier coating has a thickness of 4000 μm. The specific steps are as follows:

[0133] Step 1: Preparation of composite powder by self-propagating combustion. Zirconium powder, boron powder, silicon powder, and commercial yttrium oxide were mixed in a volume ratio of 7:5.5:7:3 to 7:6:7:3.5. The powder was synthesized by low-temperature exothermic combustion in a self-propagating furnace under an argon atmosphere at a pressure of 5 MPa.

[0134] Step 2: Sintering of the coating. The powder block synthesized by self-propagating combustion is crushed and then ball-milled with 40% SiC added by volume at a ball mill speed of 350 r / min for 5 h. The composite powder is then placed into a plasma spark sintering mold with a diameter of 15 mm. The heating rate is 100℃ / min, the sintering temperature is 1500℃, the holding time is 5 min, and the sintering pressure is 30 MPa.

[0135] Step 3: Film formation treatment of biomimetic glass film. The Zr-YO solid solution powder prepared by microwave preheating combustion synthesis is mixed with silica sol to form a colloid. The colloid is brushed onto the coating surface and dried in a constant temperature drying oven at 50℃ for 30s. The composite coating is then placed in a high temperature resistance furnace for film formation treatment at a heat treatment temperature of 1200℃ for 100min.

[0136] The oxidation protection efficiency results at 1700℃ are shown in Table 1. The results show that, compared with Examples 1-7, the oxidation protection efficiency at 1700℃ is significantly inferior, indicating the advantage and necessity of using microwave preheating combustion synthesis to prepare Y2O3 in this invention to improve the oxidation protection effect of the coating.

[0137] Protection efficiency / % Example 1 99.705 Example 2 99.714 Example 3 99.724 Example 4 99.747 Example 5 99.789 Example 6 99.799 Example 7 99.809 Comparative Example 1 99.459 Comparative Example 2 99.078 Comparative Example 3 99.334 Comparative Example 4 99.223

[0138] Table 1 Results of Coating Oxidation Protection Efficiency at 1700℃

[0139] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-heat technology combined with bionic glass membrane synergistic oxygen resistance, characterized in that, The substrate layer, the transition layer and the biomimetic glass layer are sequentially arranged. The substrate layer comprises graphite substrate material. The transition layer comprises Y2O3-ZrSi2-ZrB2-SiC coating. The biomimetic glass layer comprises Zr-Y-Si-O glass film. The substrate layer and the biomimetic glass layer are respectively arranged at the innermost side and the outermost side, and the transition layer is arranged between the substrate layer and the biomimetic glass layer. The transition layer is composed of Y2O3-ZrSi2-ZrB2-SiC, the doping content of rare earth oxide Y2O3 in the transition layer is 0.5-3.5mol%, the doping content of binary silicide ZrSi2 is 1-4.0mol%, and the rest is ZrB2-SiC main phase ceramic. The surface of the biomimetic glass layer is composed of oxidation products ZrO2, ZrSiO4, Y2Si2O7 and unreacted ZrB2 and SiC.

2. The composite ceramic coating of claim 1, wherein, The thickness of the transition layer is 1000-4000μm.

3. The composite ceramic coating of claim 1, wherein, The thickness of the biomimetic glass layer is 500-1500μm.

4. The preparation method of Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating based on low-energy self-exothermic technology combined with biomimetic glass membrane and oxygen-blocking according to any one of claims 1-3, characterized in that, The method comprises the following steps: Step 1: preparing urea-yttrium nitrate mixed solution Y(NO3)3·6H2O is weighed and dissolved in deionized water to obtain yttrium aqueous solution, and then urea is weighed and added into the yttrium aqueous solution, and stirred uniformly to ensure that the urea is completely dissolved, thereby obtaining urea-yttrium nitrate mixed solution; Step 2: low-energy self-heating combustion synthesis of Y2O3 powder The urea-yttrium nitrate mixed solution obtained in step 1 is placed in a crucible and placed in an electric furnace, and the solution is quickly heated to 150-200℃ by trigger type microwave preheating, in the process, urea begins to decompose and reacts with yttrium nitrate, releasing heat, and combustion reaction occurs, the heat released after combustion makes the reaction rapidly heat up, and finally Y2O3 powder is formed; Step 3: preparing urea-zirconium nitrate-yttrium nitrate mixed solution Zr(NO3)4·5H2O, Y(NO3)3·6H2O and urea are weighed and dissolved in deionized water, and then mixed uniformly by a magnetic stirrer to obtain urea-zirconium nitrate-yttrium nitrate mixed solution; Step 4: low-energy self-heating combustion synthesis of Zr-Y-O solid solution powder The urea-zirconium nitrate-yttrium nitrate mixed solution obtained in step 3 is placed in a crucible and placed in an electric furnace, and the solution is quickly heated to 650-700℃ by trigger type microwave preheating, in the process, urea begins to decompose and reacts with yttrium nitrate and zirconium nitrate, releasing heat, and combustion reaction occurs, the heat released after combustion makes the reaction rapidly heat up, and finally Zr-Y-O solid solution powder is formed; Step 5: preparing mixed powder Zirconium powder, boron powder, silicon powder and yttrium oxide are mixed in a volume ratio of 6:3:7:1-6:5:8:1.5, and then the mixed powder is obtained by ball milling through a ball mill; Step 6: self-propagating combustion synthesis of powder The mixed powder obtained in step 5 is pressed into a block by a tablet press, and the powder is synthesized by low-temperature heat release under an argon atmosphere through a self-propagating combustion synthesis furnace; Step 7: coating sintering The powder from the self-propagating combustion synthesis of step 6 is wrapped with graphite base material, filled into a graphite mold, and plasma spark sintered in a vacuum environment to obtain a Y2O3-ZrSi2-ZrB2-SiC coating; Step 8: film forming treatment The Zr-Y-O solid solution powder obtained in step 4 is mixed with silica sol to form a colloid, which is then brushed on the surface of the Y2O3-ZrSi2-ZrB2-SiC coating obtained in step 7 and placed in a muffle furnace for film forming treatment to form a Zr-Y-Si-O glass film, thereby obtaining a Y2O3-ZrSi2-ZrB2-SiC composite ceramic coating.

5. The preparation method of claim 4, wherein, The molar ratio of Y(NO3)3·6H2O to urea in step 1 is (3:7)-(4:9). The molar ratio of Zr(NO3)4·5H2O, Y(NO3)3·6H2O, and urea in step 3 is (3:2:5)-(4:3:16).

6. The preparation method according to claim 4, characterized in that, The grain size of the Y2O3 powder synthesized in step 2 is 65-70 nm.

7. The preparation method according to claim 4, characterized in that, The grain size of the Zr-Y-O solid solution powder synthesized in step 4 is 70-75 nm.

8. The preparation method according to claim 4, characterized in that, The preheating temperature of the self-propagating combustion synthesis furnace in step 6 is 750-800℃, and a tungsten wire with a diameter of 1.5 mm is used for ignition.

9. The preparation method according to claim 4, characterized in that, The temperature of the plasma spark sintering in step 7 is 1450-1500℃, the heating rate is 50℃ / min, and the sintering pressure is 30-35 MPa.

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