Anti-oxidation and ablation-resistant ceramic coating on surface of C / C composite material and preparation method of anti-oxidation and ablation-resistant ceramic coating

Abstract

The invention provides an anti-oxidation and ablation-resistant ceramic coating on the surface of a C / C composite material and a preparation method, and belongs to the technical field of thermal protection coatings. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material comprises a bottom bonding layer, a middle heat insulation layer and an external ablation-resistant layer, the bottom bonding layer is SiC-SiCf, the middle heat insulation layer is modified ZrO2, and the external ablation-resistant layer is HfC-ZrC-SiCf. According to the method, the SiC-SiCf / modified ZrO2 / HfC-ZrC-SiCf composite ceramic coating is prepared on the special-shaped part through dipping and brushing methods, the method is easy and convenient to operate, few in material consumption and low in cost, and the performance meets the specific use requirement.

Description

Technical Field

[0001] This invention relates to the field of thermal protective coating technology, and in particular to an antioxidant and ablation-resistant ceramic coating for C / C composite material surfaces and its preparation method. Background Technology

[0002] C / C composites possess excellent high-temperature mechanical properties and good thermal shock resistance, overcoming the shortcomings of ceramic materials such as low fracture toughness and poor impact load resistance. They are widely used in key components of aircraft and rocket engines, meeting the stringent strength and density requirements of future high-performance aerospace engines. However, despite these advantages, C / C composites are highly susceptible to severe oxidation and ablation in aerobic environments above approximately 400°C. A 4%-5% ablation mass loss in C / C composites can lead to a 30-50% loss in mechanical properties. Therefore, the ablation problem of C / C composites under oxidizing conditions significantly limits their application in the aerospace field. Currently, there are generally two methods for improving C / C composites both domestically and internationally: matrix modification and coating modification. Coating modification involves creating a coating on the surface of the C / C composite to isolate the matrix from the high-temperature aerobic environment. Compared to matrix modification, coating modification is simpler in process, less time-consuming, and relatively cheaper to prepare, without affecting the mechanical properties of the matrix itself.

[0003] HfC and ZrC, as coatings, exhibit good oxidation and ablation resistance under ablation temperatures above 2000℃ and erosion conditions. When HfC and ZrC are combined with SiC fibers (SiC... f When used together, these two methods offer two main advantages: first, the introduction of SiC optimizes the coating's coefficient of thermal expansion, enhancing its self-healing ability at high temperatures; second, the fiber-reinforced phase effectively releases stress during peeling, pull-out, and fracture, thereby improving the overall toughness and strength of the coating. Modifying ZrO2 with rare earth elements helps stabilize the t-ZrO2 phase, reducing volume changes at high temperatures. As a surface coating, it provides good thermal shielding and has low volatility, effectively preventing high-temperature flame erosion of the substrate. By constructing double- or multi-layer coatings, multiple functions can be integrated into a single coating, giving it advantages such as high-temperature stability, thermal insulation, and erosion resistance.

[0004] Currently, most ceramic coatings are prepared using chemical vapor deposition (CVD). However, CVD typically requires high temperature, low vacuum, and a protective atmosphere, placing high demands on equipment, resulting in expensive deposition sources and long deposition cycles. In contrast, thermal spraying processes, such as plasma spraying, offer higher deposition efficiency and better control over coating composition and thickness. However, they may suffer from insufficient coating density and weak adhesion between the coating and the substrate, especially at the corners of irregularly shaped components, where the adhesion is weak and prone to failure at high temperatures. Therefore, to meet the application requirements of C / C composite irregularly shaped components, it is necessary to develop coating preparation methods that are simple to operate, require fewer materials, and are lower in cost. Summary of the Invention

[0005] In view of this, the present invention provides an anti-oxidation and ablation-resistant ceramic coating for the surface of C / C composite materials and its preparation method. The present invention achieves SiC-SiC coating through impregnation and brushing methods. f / Modified ZrO2 / HfC-ZrC-SiC f The method for preparing composite ceramic coatings on irregularly shaped parts is simple to operate, requires little material, has low cost, and its performance meets specific application requirements.

[0006] To achieve the above effects, the present invention adopts the following technical solution:

[0007] The first objective of this invention is to provide an oxidation-resistant and ablation-resistant ceramic coating for the surface of a C / C composite material, comprising a bottom adhesive layer, an intermediate heat-insulating layer, and an outer ablation-resistant layer, wherein the bottom adhesive layer is SiC-SiC. f The intermediate heat insulation layer is modified ZrO2, and the outer ablation-resistant layer is HfC-ZrC-SiC. f .

[0008] Furthermore, the bottom adhesive layer comprises 5-20 wt% silicon carbide fiber, 20-60% silicon carbide, and the remainder being silicon powder.

[0009] Furthermore, the intermediate heat insulation layer comprises 85-95 wt% zirconium oxide, 3-5 wt% yttrium oxide, and 2-6% gallium oxide by mass.

[0010] Furthermore, the mass percentage of the external ablation-resistant layer is 10-20 wt% silicon carbide fiber, 20-50 wt% zirconium carbide, and 20-70 wt% hafnium carbide.

[0011] Furthermore, the particle size of the silicon powder is less than 1 micrometer.

[0012] Furthermore, the SiC-SiC fThe thickness is controlled within the range of 100-250 micrometers, and the thickness of the modified ZrO2 is controlled within the range of 150-250 micrometers. The HfC-ZrC-SiC... f The thickness is controlled within the range of 150-350 micrometers.

[0013] A second objective of this invention is to provide a method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of the C / C composite material, comprising the following steps:

[0014] (1) Silicon carbide fiber, silicon carbide, and silicon powder are placed in a dispersant, additives are added, and the mixture is ball-milled to obtain slurry A;

[0015] (2) Zirconia, yttrium oxide and gallium oxide are placed in a dispersant, additives are added, and the mixture is ball-milled to obtain slurry B;

[0016] (3) Place silicon carbide fiber, zirconium carbide and hafnium carbide in a dispersant, add additives, mix and ball mill to obtain slurry C;

[0017] (4) The C / C composite material is impregnated in slurry A and then subjected to high-temperature treatment to form SiC-SiC on the surface of the C / C composite material. f The coating is then applied by coating slurry B onto SiC-SiC. f After high-temperature treatment, a SiC-SiC coating is formed on the surface. f / Modified ZrO2 coating, slurry C is coated onto SiC-SiC f / Modified ZrO2 coating surface, after high temperature treatment, forms SiC-SiC f / Modified ZrO2 / HfC-ZrC-SiC f The coating is subjected to a staged high-temperature sintering process under an inert atmosphere to obtain an oxidation-resistant and ablation-resistant ceramic coating.

[0018] Furthermore, the dispersant is selected from at least one of ethanol, toluene, and water, and the amount of the dispersant added is 1-2 times the powder mass. The additive is selected from at least one of polyethylene glycol, polyacrylol, and polyvinylpyrrolidone, and the amount of the additive added is 3-5 wt% of the powder mass.

[0019] Furthermore, the high-temperature treatment temperature is 120-200℃, and the high-temperature treatment time is 1-4 hours.

[0020] Furthermore, the staged high-temperature sintering process involves first heating to 1000-1200℃ and holding for 1-3 hours, then heating to 1700-1900℃ and holding for 1-8 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of C / C composite materials provided by this invention is a simple impregnation and brushing process. It requires no complex equipment or additional high-temperature and high-pressure environments, and does not require ceramic precursors. It uses only inexpensive ceramic powder particles as raw materials to achieve the preparation of SiC-SiC-containing coatings on the surface of irregularly shaped C / C composite parts with controllable thickness. f / Modified ZrO2 / HfC-ZrC-SiC f The effect of anti-oxidation and ablation resistant ceramic coatings.

[0023] The method for preparing the antioxidant and ablation-resistant ceramic coating provided by this invention is simple to operate, requires few materials, has low cost, and its performance meets specific application requirements, making it suitable for industrial production.

[0024] The coating composition and thickness prepared by this invention are adjustable, and it is suitable for preparing coatings on the surface of irregularly shaped parts. Attached Figure Description

[0025] Figure 1 This is a comparison image of C / C composite material samples with and without coating. Detailed Implementation

[0026] This invention provides an oxidation-resistant and ablation-resistant ceramic coating for the surface of a C / C composite material, comprising a bottom adhesive layer, an intermediate heat-insulating layer, and an outer ablation-resistant layer, wherein the bottom adhesive layer is SiC-SiC. f The intermediate heat insulation layer is modified ZrO2, and the outer ablation-resistant layer is HfC-ZrC-SiC. f .

[0027] This invention uses SiC, which has a similar coefficient of thermal expansion to C / C composites and good chemical compatibility, as the bottom adhesive layer, and introduces SiC... f This invention further enhances the thermal shock resistance and self-healing properties of the underlying layer. It uses modified ZrO2, which boasts excellent thermal insulation, high oxidation resistance, and low oxygen permeability, as the intermediate thermal insulation layer. Furthermore, it employs HfC-ZrC, with its high melting point and superior high-temperature performance, as the external ablation-resistant layer and introduces SiC. f Further enhancing erosion and thermal shock resistance, increasing the number of reusable applications, the various coatings work synergistically to form SiC-SiC f / Modified ZrO2 / HfC-ZrC-SiC f The antioxidant and ablation-resistant ceramic coating prepared by this invention can withstand ablation for more than 100 seconds at 2200℃ and can be reused.

[0028] In one embodiment of the present invention, the bottom adhesive layer comprises 5-20 wt% silicon carbide fiber, 20-60% silicon carbide, and the balance being silicon powder. Preferably, the bottom adhesive layer comprises 6-12 wt% silicon carbide fiber, 28-40% silicon carbide, and the balance being silicon powder. More preferably, the bottom adhesive layer comprises 7 wt% silicon carbide fiber, 35% silicon carbide, and the balance being silicon powder.

[0029] In one embodiment of the present invention, the intermediate heat insulation layer has a mass percentage of 85-95 wt% zirconium oxide, 3-5 wt% yttrium oxide, and 2-6% gallium oxide. More preferably, the intermediate heat insulation layer has a mass percentage of 92 wt% zirconium oxide, 4 wt% yttrium oxide, and 4% gallium oxide.

[0030] In one embodiment of the present invention, the mass percentage of the external ablation-resistant layer is 10-20 wt% silicon carbide fiber, 20-50 wt% zirconium carbide, and 20-70 wt% hafnium carbide. More preferably, the mass percentage of the external ablation-resistant layer is 15 wt% silicon carbide fiber, 25 wt% zirconium carbide, and 60 wt% hafnium carbide.

[0031] In one embodiment of the present invention, the particle size of the silicon powder is less than 1 micrometer.

[0032] In one embodiment of the present invention, the SiC-SiC f The thickness is controlled within the range of 100-250 micrometers, and the thickness of the modified ZrO2 is controlled within the range of 150-250 micrometers. The HfC-ZrC-SiC... f The thickness is controlled within the range of 150-350 micrometers.

[0033] This invention also provides a method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of the C / C composite material, comprising the following steps:

[0034] (1) Silicon carbide fiber, silicon carbide, and silicon powder are placed in a dispersant, additives are added, and the mixture is ball-milled to obtain slurry A;

[0035] (2) Zirconia, yttrium oxide and gallium oxide are placed in a dispersant, additives are added, and the mixture is ball-milled to obtain slurry B;

[0036] (3) Place silicon carbide fiber, zirconium carbide and hafnium carbide in a dispersant, add additives, mix and ball mill to obtain slurry C;

[0037] (4) The C / C composite material is impregnated in slurry A and then subjected to high-temperature treatment to form SiC-SiC on the surface of the C / C composite material. f The coating is then applied by coating slurry B onto SiC-SiC. fAfter high-temperature treatment, a SiC-SiC coating is formed on the surface. f / Modified ZrO2 coating, slurry C is coated onto SiC-SiC f / Modified ZrO2 coating surface, after high temperature treatment, forms SiC-SiC f / Modified ZrO2 / HfC-ZrC-SiC f The coating is subjected to a staged high-temperature sintering process under an inert atmosphere to obtain an oxidation-resistant and ablation-resistant ceramic coating.

[0038] In one embodiment of the present invention, the dispersant is selected from at least one of ethanol, toluene, and water. Preferably, the dispersant is ethanol and toluene, which can reduce the surface tension of the slurry, improve the thick edge phenomenon after coating, and reduce pores after high-temperature treatment. The amount of the dispersant added is 1-2 times the powder mass. The additive is selected from at least one of polyethylene glycol, polyacryl alcohol, and polyvinylpyrrolidone. Preferably, the additive is polyacryl alcohol, which enhances the bonding force between the particles of each component and helps to form a denser coating after high-temperature treatment. The amount of the additive added is 3-5 wt% of the powder mass, preferably 3 wt% of the powder mass.

[0039] In one embodiment of the present invention, the temperature of the high-temperature treatment is 120-200°C, and the time of the high-temperature treatment is 1-4 hours. Preferably, the temperature of the high-temperature treatment is 150°C, and the time of the high-temperature treatment is 3 hours.

[0040] In one embodiment of the present invention, the staged high-temperature sintering treatment involves first heating to 1000-1200℃ and holding for 1-3 hours, then heating to 1700-1900℃ and holding for 1-3 hours. Preferably, the staged high-temperature sintering treatment involves first heating to 1100℃ and holding for 2 hours, then heating to 1800℃ and holding for 2 hours. The initial firing stage removes organic matter and activates the ceramic particle surface before entering the high-temperature sintering stage, achieving grain rearrangement and densification, thereby improving the coating's density and toughness.

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0042] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0043] Example 1

[0044] A method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of a C / C composite material, comprising the following specific steps:

[0045] (1) 7wt% silicon carbide fiber, 35wt% silicon carbide and the balance of silicon powder are placed in an ethanol dispersant, the amount of the dispersant added is twice the mass of the powder, and then polyacryl alcohol additive is added, the amount of the additive added is 3wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 3 hours to obtain slurry A.

[0046] (2) 92wt% zirconium oxide, 4wt% yttrium oxide and 4wt% gallium oxide are placed in a dispersant, the amount of ethanol dispersant added is twice the powder mass, and then polyacryl alcohol additive is added, the amount of additive added is 3wt% of the powder mass, and the mixture is ball-milled at a speed of 450 rpm for 6-8 hours to obtain slurry B.

[0047] (3) 15wt% silicon carbide fiber, 25wt% zirconium carbide and 60wt% hafnium carbide are placed in an ethanol dispersant, the amount of the dispersant added is twice the mass of the powder, and then polyacryl alcohol additive is added, the amount of the additive added is 3wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 8 hours to obtain slurry C.

[0048] (4) After grinding and polishing the irregular C / C composite material, ultrasonically clean it with distilled water and ethanol for 30 min, dry it, impregnate it in slurry A, and vacuum it to 1×10 -3 The impregnation process is carried out at a pressure below 10 Pa, then argon gas is introduced and allowed to stand for 10-30 minutes. Next, the impregnated shaped C / C composite material is dried under an argon atmosphere by heating at 120°C for 1 hour. This impregnation and drying process is repeated 2-3 times to obtain a SiC-SiC composite material with a thickness of approximately 100 micrometers. f coating;

[0049] Next, slurry B is uniformly coated onto SiC-SiC. f The coating surface was evacuated to a vacuum level of 1×10. -3 Below Pa, argon gas is introduced and allowed to stand for 20 minutes, followed by drying under an argon atmosphere. The drying conditions are heating at 120°C for 1 hour to form a modified ZrO2 coating with a thickness of about 200 micrometers.

[0050] Slurry C is uniformly coated onto SiC-SiC f / Modified ZrO2 coating surface, vacuumed to 1×10 -3Below Pa, argon gas is introduced and allowed to stand for 20 minutes, followed by drying under an argon atmosphere. The drying conditions are: heating at 120°C for 1 hour, then increasing to 200°C and heating for 4 hours, forming an HfC-ZrC-SiC layer with a thickness of approximately 350 micrometers. f coating;

[0051] SiC-SiC f / Modified ZrO2 / HfC-ZrC-SiC f The coated irregular C / C composite material was placed in a vacuum furnace and evacuated to 5×10⁻⁶. -4 Argon gas was introduced when the temperature was below Pa, then the temperature was raised to 1100℃ and held for 2 hours, then raised to 1800℃ and held for 2 hours, and then cooled down with the furnace to obtain a product with SiC-SiC on the surface. f / Modified ZrO2 / HfC-ZrC-SiC f C / C composite material irregular parts with anti-oxidation and ablation resistant composite ceramic coating.

[0052] Example 2

[0053] A method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of a C / C composite material, comprising the following specific steps:

[0054] (1) 5 wt% silicon carbide fiber, 55% silicon carbide, and the remainder silicon powder are placed in toluene dispersant, the amount of the dispersant added is twice the mass of the powder, and then polyvinylpyrrolidone additive is added, the amount of the additive added is 3 wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 6 hours to obtain slurry A.

[0055] (2) 90wt% zirconium oxide, 5wt% yttrium oxide and 5wt% gallium oxide are placed in a dispersant, the amount of toluene dispersant added is twice the mass of the powder, and then polyvinylpyrrolidone additive is added, the amount of the additive added is 3wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 8 hours to obtain slurry B.

[0056] (3) 10wt% silicon carbide fiber, 20wt% zirconium carbide and 70wt% hafnium carbide are placed in toluene dispersant, the amount of the dispersant added is twice the mass of the powder, and then polyvinylpyrrolidone additive is added, the amount of the additive added is 3wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 8 hours to obtain slurry C.

[0057] (4) After grinding and polishing the irregular C / C composite material, ultrasonically clean it with distilled water and ethanol for 30 min, dry it, impregnate it in slurry A, and vacuum it to 1×10 -3The impregnation process is carried out at a pressure below 1 Pa, then argon gas is introduced and allowed to stand for 10-30 minutes. Next, the impregnated shaped C / C composite material is dried under an argon atmosphere. The drying conditions are heating at 120°C for 1 hour. This impregnation and drying process is repeated 2-3 times to obtain a SiC-SiC composite material with a thickness of approximately 150 micrometers. f coating;

[0058] Next, slurry B is uniformly coated onto SiC-SiC. f The coating surface was evacuated to a vacuum level of 1×10. -3 Below Pa, argon gas is introduced and allowed to stand for 20 minutes, followed by drying under an argon atmosphere. The drying conditions are heating at 120°C for 1 hour to form a modified ZrO2 coating with a thickness of about 250 micrometers.

[0059] Slurry C is uniformly coated onto SiC-SiC f / Modified ZrO2 coating surface, vacuumed to 1×10 -3 Below Pa, argon gas is introduced and allowed to stand for 20 minutes, followed by drying under an argon atmosphere. The drying conditions are: heating at 120°C for 1 hour, then increasing to 200°C and heating for 4 hours, forming an HfC-ZrC-SiC layer with a thickness of approximately 350 micrometers. f coating;

[0060] SiC-SiC f / Modified ZrO2 / HfC-ZrC-SiC f The coated irregular C / C composite material was placed in a vacuum furnace and evacuated to 5×10⁻⁶. -4 Argon gas was introduced when the temperature was below Pa, then the temperature was raised to 1100℃ and held for 3 hours, then raised to 1800℃ and held for 6 hours, and then cooled down with the furnace to obtain a product with SiC-SiC on the surface. f / Modified ZrO2 / HfC-ZrC-SiC f C / C composite material irregular parts with anti-oxidation and ablation resistant composite ceramic coating.

[0061] Compared to Example 1, Comparative Example 1 below is SiC-SiC f / Modified ZrO2 coating, the coating in Comparative Example 2 is HfC-ZrC-SiC f Coating. In the preparation process, Comparative Example 1 contained only slurry A and slurry B, and Comparative Example 3 contained only slurry C. The detailed preparation process is as follows:

[0062] Comparative Example 1

[0063] A method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of a C / C composite material, comprising the following specific steps:

[0064] (1) 7wt% silicon carbide fiber, 35% silicon carbide and the balance of silicon powder are placed in an ethanol dispersant, the amount of the dispersant added is twice the mass of the powder, and then polyacryl alcohol additive is added, the amount of the additive added is 3wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 3 hours to obtain slurry A.

[0065] (2) 92wt% zirconium oxide, 4wt% yttrium oxide and 4wt% gallium oxide are placed in a dispersant, the amount of ethanol dispersant added is twice the powder mass, and then polyacryl alcohol additive is added, the amount of additive added is 3wt% of the powder mass, and the mixture is ball-milled at a speed of 450 rpm for 6-8 hours to obtain slurry B.

[0066] (3) After grinding and polishing the irregular C / C composite material, ultrasonically clean it with distilled water and ethanol for 30 min, dry it, impregnate it in slurry A, and vacuum it to 1×10 -3 The impregnation process is carried out at a pressure below 10 Pa, then argon gas is introduced and allowed to stand for 10-30 minutes. Next, the impregnated shaped C / C composite material is dried under an argon atmosphere by heating at 120°C for 1 hour. This impregnation and drying process is repeated 2-3 times to obtain a SiC-SiC composite material with a thickness of approximately 100 micrometers. f coating;

[0067] Next, slurry B is uniformly coated onto SiC-SiC. f The coating surface was evacuated to a vacuum level of 1×10. -3 Below Pa, argon gas is introduced and allowed to stand for 20 minutes, followed by drying under an argon atmosphere. The drying conditions are heating at 120°C for 1 hour to form a modified ZrO2 coating with a thickness of about 200 micrometers.

[0068] SiC-SiC f The modified ZrO2-coated irregular C / C composite material was placed in a vacuum furnace and evacuated to 5 × 10⁻⁶. -4 Argon gas was introduced when the temperature was below Pa, then the temperature was raised to 1100℃ and held for 2 hours, then raised to 1800℃ and held for 2 hours, and then cooled down with the furnace to obtain a product with SiC-SiC on the surface. f C / C composite irregular parts with modified ZrO2 anti-oxidation and ablation resistant composite ceramic coating.

[0069] Comparative Example 2

[0070] A method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of a C / C composite material, comprising the following specific steps:

[0071] (1) 15wt% silicon carbide fiber, 25wt% zirconium carbide and 60wt% hafnium carbide were placed in an ethanol dispersant, the amount of the dispersant being twice the mass of the powder, and then polyacryl alcohol additive was added, the amount of the additive being 3wt% of the mass of the powder. The mixture was ball-milled at a speed of 450 rpm for 8 hours to obtain slurry C.

[0072] (2) After grinding and polishing the irregular C / C composite material, ultrasonically clean it with distilled water and ethanol for 30 min, dry it, and then uniformly coat the surface with slurry C. Vacuum the surface to 1×10⁻⁶. -3 Below Pa, argon gas is introduced and allowed to stand for 20 minutes, followed by drying under an argon atmosphere. The drying conditions are: heating at 120°C for 1 hour, then increasing to 200°C and heating for 4 hours, forming an HfC-ZrC-SiC layer with a thickness of approximately 350 micrometers. f coating;

[0073] The surface has HfC-ZrC-SiC f The coated irregular C / C composite material was placed in a vacuum furnace and evacuated to 5×10⁻⁶. -4 Argon gas was introduced when the temperature was below Pa, then the temperature was raised to 1100℃ and held for 2 hours, then raised to 1800℃ and held for 2 hours, and then cooled down with the furnace to obtain HfC-ZrC-SiC. f C / C composite material irregular parts with anti-oxidation and ablation resistant composite ceramic coating.

[0074] In a plasma flame ablation experiment at 2200℃, Example 1 withstood ablation for 100 seconds at 2200℃. After cooling to room temperature, the coating showed no damage or cracking. After another 100-second ablation test at 2200℃, the coating remained relatively intact with no significant peeling; only the edge areas showed damage. This demonstrates that the coating of Example 1 can withstand ablation for more than 100 seconds at 2200℃ and can be reused. In Comparative Example 1, under the same experimental conditions, after 40 seconds of ablation at 2200℃, the coating at the flame center melted. The molten phase was rapidly blown to the edges by the flame, leaving the center unprotected and causing ablation of the substrate. In Comparative Example 2, under the same experimental conditions, the coating developed significant cracks at the center during the heating phase due to high-temperature impact. As the cracks gradually expanded, the flame penetrated the coating after approximately 20 seconds, causing severe ablation of the substrate. Through these ablation experiments, it is demonstrated that the technical solution of this invention achieves the technical effects of improving coating density, enhancing the adhesion between the coating and the substrate, and improving oxidation and ablation resistance.

[0075] Compared to Example 1, Comparative Example 3 below is a coating prepared by plasma spraying, because the fiber-reinforced SiC phase... fThe introduction of [a specific ingredient] affects the sphericity after granulation. Poor sphericity is detrimental to the plasma spraying process. Therefore, only SiC / modified ZrO2 / HfC-ZrC-SiC coatings were successfully prepared as Comparative Example 3. The detailed preparation process is as follows:

[0076] Comparative Example 3

[0077] A method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of a C / C composite material, comprising the following specific steps:

[0078] (1) 42% silicon carbide and the remainder silicon powder were placed in an ethanol dispersant, the amount of the dispersant being twice the mass of the powder, and then polyacryl alcohol additive was added, the amount of the additive being 0.8 wt% of the mass of the powder. The mixture was ball-milled at a speed of 450 rpm for 3 hours to obtain slurry A.

[0079] (2) 92wt% zirconium oxide, 4wt% yttrium oxide and 4% gallium oxide are placed in a dispersant, the amount of ethanol dispersant added is twice the mass of the powder, and then polyacryl alcohol additive is added, the amount of the additive added is 1wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 6-8 hours to obtain slurry B.

[0080] (3) 15wt% silicon carbide, 25wt% zirconium carbide and 60wt% hafnium carbide are placed in an ethanol dispersant, the amount of the dispersant added is twice the mass of the powder, and then polyacryl alcohol additive is added, the amount of the additive added is 1wt% of the mass of the powder, and the mixture is ball-milled at a speed of 450 rpm for 8 hours to obtain slurry C.

[0081] (4) After spray drying, the A, B and C slurries are atomized and granulated, and after sieving, agglomerated composite powders A, B and C with a particle size of 10 to 100 micrometers are obtained.

[0082] (5) After grinding and polishing the irregular C / C composite material, it is ultrasonically cleaned with distilled water and ethanol for 30 minutes. After drying, composite powders A, B and C are sequentially sprayed onto the surface by plasma spraying to obtain an irregular C / C composite material part with SiC / modified ZrO2 / HfC-ZrC-SiC anti-oxidation and ablation resistant composite ceramic coating.

[0083] In a plasma flame ablation experiment at 2200℃, the coating at the corners of the irregularly shaped part in Comparative Example 3 gradually peeled off after more than 10 seconds of ablation, exposing the substrate and causing significant ablation. In contrast, after a 100-second ablation test at 2200℃, the coating in Example 1 remained relatively intact with no significant peeling. This demonstrates that the impregnation and brushing techniques of the present invention have certain advantages over plasma spraying in the preparation of coatings for irregularly shaped parts.

[0084] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A C / C composite material surface anti-oxidation and ablation-resistant ceramic coating, comprising a bottom adhesive layer, an intermediate heat insulation layer, and an outer ablation-resistant layer, characterized in that, The bottom adhesive layer is SiC-SiC. f The intermediate heat insulation layer is modified ZrO2, and the outer ablation-resistant layer is HfC-ZrC-SiC. f .

2. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 1, characterized in that, The bottom adhesive layer consists of 5-20 wt% silicon carbide fiber, 20-60% silicon carbide, and the remainder is silicon powder.

3. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 1, characterized in that, The intermediate heat insulation layer has the following mass percentages: 85-95 wt% zirconium oxide, 3-5 wt% yttrium oxide, and 2-6% gallium oxide.

4. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 1, characterized in that, The external ablation-resistant layer comprises 10-20 wt% silicon carbide fiber, 20-50 wt% zirconium carbide, and 20-70 wt% hafnium carbide by mass.

5. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 2, characterized in that, The silicon powder has a particle size of less than 1 micrometer.

6. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 1, characterized in that, The SiC-SiC f The thickness is controlled within the range of 100-250 micrometers, and the thickness of the modified ZrO2 is controlled within the range of 150-250 micrometers. The HfC-ZrC-SiC... f The thickness is controlled within the range of 150-350 micrometers.

7. The method for preparing an antioxidant and ablation-resistant ceramic coating on the surface of the C / C composite material according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Silicon carbide fiber, silicon carbide, and silicon powder are placed in a dispersant, additives are added, and the mixture is ball-milled to obtain slurry A; (2) Zirconia, yttrium oxide and gallium oxide are placed in a dispersant, additives are added, and the mixture is ball-milled to obtain slurry B; (3) Place silicon carbide fiber, zirconium carbide and hafnium carbide in a dispersant, add additives, mix and ball mill to obtain slurry C; (4) The C / C composite material is impregnated in slurry A and then subjected to high-temperature treatment to form SiC-SiC on the surface of the C / C composite material. f The coating is then applied by coating slurry B onto SiC-SiC. f After high-temperature treatment, a SiC-SiC coating is formed on the surface. f / Modified ZrO2 coating, slurry C is coated onto SiC-SiC f / Modified ZrO2 coating surface, after high temperature treatment, forms SiC-SiC f / Modified ZrO2 / HfC-ZrC-SiC f The coating is subjected to a staged high-temperature sintering process under an inert atmosphere to obtain an oxidation-resistant and ablation-resistant ceramic coating.

8. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 7, characterized in that, The dispersant is selected from at least one of ethanol, toluene, and water, and the amount of the dispersant added is 1-2 times the powder mass. The additive is selected from at least one of polyethylene glycol, polyacrylol, and polyvinylpyrrolidone, and the amount of the additive added is 3-5 wt% of the powder mass.

9. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 7, characterized in that, The high-temperature treatment is performed at a temperature of 120-200℃ for 1-4 hours.

10. The anti-oxidation and ablation-resistant ceramic coating on the surface of the C / C composite material according to claim 7, characterized in that, The phased high-temperature sintering process involves first heating to 1000-1200℃ and holding for 1-3 hours, then heating to 1700-1900℃ and holding for 1-8 hours.

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