Cold spraying preparation method of anti-oxidation coating on surface of C / C composite material

Abstract

The invention relates to the technical field of cold spraying, in particular to a cold spraying preparation method of an anti-oxidation coating on the surface of a C / C composite material. Brazing is carried out on the C / C composite material matrix to prepare a welding brazing filler metal coating; preparing composite powder of an anti-oxidation coating; and carrying out cold spraying on the brazing filler metal coating on the surface of the C / C composite material to form the anti-oxidation coating. According to the method provided by the invention, the continuous and compact anti-oxidation coating can be prepared on the surface of the C / C composite material, so that the high-temperature oxidation resistance of the C / C composite material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cold spraying, and in particular to a cold spraying preparation method of an anti-oxidation coating on the surface of a C / C composite material. Background Art

[0002] C / C composites are considered to be one of the ideal high-temperature structural materials due to their excellent properties such as high strength, low density, high temperature resistance and thermal shock resistance. However, in an oxidizing atmosphere, C / C composites will oxidize in an oxygen-containing environment above 400°C, and the oxidation rate will significantly accelerate as the temperature rises further. This oxidation seriously weakens the mechanical properties of C / C composites, making them unable to meet the performance requirements in practical applications.

[0003] The application of C / C composites as ultra-high temperature structural materials in the aerospace field is limited by their oxidation sensitivity. In order to ensure that C / C composites can serve stably for a long time in high-temperature oxygen-containing environments, the most effective method at present is to use surface coating technology. From the perspective of the preparation process of anti-oxidation coatings, in recent years, the surface anti-oxidation coating technologies of C / C composites mainly include chemical vapor deposition technology, physical vapor deposition technology, plasma spraying technology and thermal spraying technology. However, these methods still have the following problems: the bonding strength between the coating and the substrate is not high, and there are many pores; the process cost is high, and the coating thickness and uniformity are difficult to control; the high temperature process of coating preparation will cause thermal damage to the substrate.

[0004] Cold spraying is a solid material deposition technology that uses compressed gas as an accelerating medium. The preheated gas is mixed with fine powdered metal particles in a Laval spray gun. The particles are accelerated by the supersonic airflow spray gun to obtain a high collision velocity, and then hit the substrate at high speed in a completely solid state, causing severe plastic deformation and depositing on the substrate surface to form a coating. The low temperature characteristics of cold spraying technology can avoid harmful interface reactions in the process of traditional coating preparation technology, and the cold spray coating is tightly bonded inside and between the coating and the substrate due to the action of compressive stress, and is not easy to crack.

[0005] Compared with other surface coating preparation technologies, cold spray technology has the advantages of low temperature, no oxidation, no phase change, and high deposition efficiency. However, during the cold spray process, particles hit the substrate at high speed, making it difficult to directly prepare anti-oxidation coatings on the surface of C / C composites using cold spray technology.

[0006] In order to overcome the deficiencies in the prior art, the present invention proposes a cold spraying preparation method for an anti-oxidation coating on the surface of a C / C composite material.

[0007] Therefore, it is necessary to provide a cold spraying preparation method for an anti-oxidation coating on the surface of a C / C composite material to solve the above problems. Summary of the invention

[0008] The invention provides a cold spraying preparation method of an anti-oxidation coating on the surface of a C / C composite material, so as to solve the existing problems.

[0009] The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material of the present invention adopts the following technical scheme, including:

[0010] preparing a C / C composite material matrix and a high entropy alloy brazing foil having the same size as the C / C composite material matrix;

[0011] A high entropy alloy brazing material foil is attached to the surface of a C / C composite material substrate, and the C / C composite material attached with the high entropy alloy brazing material foil is subjected to a vacuum brazing reaction to obtain a welding brazing material coating formed on the C / C composite material substrate;

[0012] Prepare cold spray powder with uniform particle size, obtain the mass ratio or volume ratio of each component in the anti-oxidation coating to be prepared according to the atomic ratio of the anti-oxidation coating to be prepared; according to the mass ratio or volume ratio of each component, mix the components of the anti-oxidation coating to be prepared according to the atomic ratio to form a composite powder of the anti-oxidation coating;

[0013] The composite powder is sprayed on the brazing material coating on the surface of the C / C composite material by cold spraying technology to form an anti-oxidation coating.

[0014] Preferably, the high entropy alloy solder foil is one of AgCuTi solder foil, NiCrSi solder foil, AgCuSn solder foil, NiTi solder foil, CuTi solder foil, CoTi solder foil, TiZrNiCu solder foil, and BNi2 solder foil.

[0015] Preferably, the thickness of the high entropy alloy solder foil is 50-150 μm.

[0016] Preferably, the steps of obtaining the solder coating formed on the C / C composite material substrate are:

[0017] Set the brazing temperature according to the high entropy alloy brazing foil;

[0018] The C / C composite material substrate with the high entropy alloy brazing foil is subjected to vacuum brazing reaction from room temperature to brazing temperature at a preset heating rate, and is kept warm for a set holding time;

[0019] After the insulation is completed, the material is cooled to room temperature at a preset cooling rate to prepare a welding brazing material coating on the surface of the C / C composite material matrix.

[0020] Preferably, the brazing temperature is 800-1300° C., the holding time is 10-120 min, the heating rate is 1-20° C. / min, and the cooling rate is 1-20° C. / min.

[0021] Preferably, the cold spraying powder raw material is sieved by a grading screen to obtain cold spraying powder with uniform particle size, wherein the particle size of the cold spraying powder is 10 to 45 μm.

[0022] Preferably, the material of the cold spraying powder includes: powder made of any two of nickel, titanium, cobalt, chromium, iron, nickel-based alloy, titanium alloy, cobalt alloy, chromium alloy, and iron alloy.

[0023] Preferably, during the cold spraying process: the working gas is nitrogen or helium, the distance between the solder coating on the surface of the C / C composite material and the spray gun is 15 to 25 cm, the carrier gas temperature is 300 to 600°C, the carrier gas pressure is 2 to 4 MPa, the spray gun moving speed is 100 to 300 mm / min, and the powder feeding rate is 100 to 180 g / min.

[0024] The beneficial effects of the present invention are:

[0025] Although C / C composites have high strength and high modulus, they often show poor impact resistance under the condition of high-speed particle impact, and are prone to cracks and fractures. In addition, the continuous impact of high-speed particles may cause the accumulation of microscopic damage inside the material, further reducing its overall structural integrity and mechanical properties. In order to solve the problem that C / C composites are difficult to directly prepare coatings on the surface due to high-speed particle impact during cold spraying, the present invention prepares a continuous and uniform brazing material coating on the surface of the C / C composite material. The chemical bonding and physical bonding formed during the brazing process enhance the interface strength between the coating and the substrate. The compactness and continuity of the coating effectively buffer the energy of high-speed particle impact, inhibit the initiation and expansion of cracks in the C / C composite material, and at the same time block the direct impact of particles on the substrate and the accumulation of microscopic damage. In addition, the good antioxidant performance of the coating significantly improves the stability of the material under high temperature environment. Combined with the cold spraying technology to deposit the antioxidant coating, the comprehensive improvement of the anti-erosion performance of the C / C composite material under extreme conditions is achieved. The method proposed in the present invention can prepare a continuous and dense antioxidant coating on the surface of the C / C composite material to improve the high temperature oxidation resistance of the C / C composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1It is a flow chart of a cold spraying preparation method of an anti-oxidation coating on the surface of a C / C composite material according to the present invention;

[0028] Figure 2 This is a SEM image of the interface reaction between the AgCuTi solder coating and the C / C composite material in Example 1 of the present invention;

[0029] Figure 3 This is a SEM image of a cross section of an anti-oxidation NiCr coating formed on the surface of a C / C composite material by the preparation method of Example 1 of the present invention;

[0030] Figure 4 This is a SEM image of the interface reaction between the AgCu solder coating and the C / C composite material in Example 2 of the present invention;

[0031] Figure 5 This is a SEM image of the cross section of an oxidation-resistant Al2O3-Al coating formed on the surface of a C / C composite material by the preparation method of Example 2 of the present invention.

[0032] Figure 6 The oxidation kinetic curve images of NiCr and Al2O3-Al cold sprayed coatings. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The steps of the cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material of the present invention are as follows: Figure 1 As shown, specifically including:

[0035] Step 1: Raw material preparation:

[0036] Specifically, a C / C composite material matrix and a high entropy alloy brazing foil having the same size as the C / C composite material matrix are prepared;

[0037] Among them, the high entropy alloy solder foil is one of AgCuTi solder foil, NiCrSi solder foil, AgCuSn solder foil, NiTi solder foil, CuTi solder foil, CoTi solder foil, TiZrNiCu solder foil, and BNi2 solder foil; the thickness of the high entropy alloy solder foil is 50 to 150 μm.

[0038] It should be noted that the high entropy alloy solder foil has excellent wetting properties and can form a good bond with the C / C composite material. The solder coating prepared on the C / C composite surface using the high entropy alloy solder foil can effectively resist the erosion caused by high-speed particle impact during cold spraying.

[0039] Step 2: Prepare a brazing brazing material coating by brazing on the C / C composite material substrate:

[0040] Specifically, a high entropy alloy solder foil is attached to the surface of a C / C composite material substrate, and the C / C composite material attached with the high entropy alloy solder foil is subjected to a vacuum brazing reaction to obtain a welding solder coating formed on the C / C composite material substrate.

[0041] The steps of obtaining the welding brazing material coating formed on the C / C composite material substrate are as follows: setting the brazing temperature according to the high entropy alloy brazing material foil; subjecting the C / C composite material substrate with the high entropy alloy brazing material foil to a vacuum brazing reaction from room temperature to the brazing temperature at a preset heating rate, and keeping the temperature at a set insulation time; after the insulation is completed, cooling to room temperature at a preset cooling rate to prepare the welding brazing material coating on the surface of the C / C composite material substrate, and the brazing temperature is 800-1300°C. The melting point range of the selected high entropy alloy solder foil is as follows: the melting point of AgCuTi solder is 800-900℃, the melting point of NiCrSi solder is 1050-1100℃, the melting point of AgCuSn solder is 780-850℃, the melting point of NiTi solder is 1310℃, the melting point of CuTi solder is 1050℃, the melting point of CoTi solder is 1200-1300℃, the melting point of TiZrNiCu solder is 1100-1300℃, and the melting point of BNi2 solder is about 1000℃. The melting point will vary according to the different alloy compositions. The holding time is 10-120min, the heating rate is 1-20℃ / min, and the preset cooling rate is 1-20℃ / min. It should be noted that the brazing temperature should be slightly higher than the melting point of the high entropy alloy solder foil.

[0042] Step 3: Prepare the composite powder for the antioxidant coating:

[0043] Specifically, prepare cold spray powder with uniform particle size, and obtain the mass ratio or volume ratio of each component in the anti-oxidation coating to be prepared according to the atomic ratio of the anti-oxidation coating to be prepared; according to the mass ratio or volume ratio of each component, mix the various components of the anti-oxidation coating to be prepared according to the atomic ratio into a composite powder of the anti-oxidation coating.

[0044] The step of preparing cold spray powder with uniform particle size is as follows: using a grading screen to sieve the cold spray powder raw material to obtain cold spray powder with uniform particle size, wherein the particle size of the cold spray powder is 10 to 45 μm.

[0045] Specifically, the materials of cold spray powder include: powders made of two of the following materials: nickel, titanium, cobalt, chromium, iron, nickel-based alloys, titanium alloys, cobalt alloys, chromium alloys, and iron alloys, that is, metals and metals, alloys and alloys, and metals and alloys. The alloys formed by these composite powders usually belong to the category of high entropy alloys. Due to their unique composition characteristics and high melting points, high entropy alloys make the coatings more stable and durable in extreme environments. The multi-element system of high entropy alloys exhibits superior oxidation resistance and corrosion resistance in high temperature and strong oxidizing environments. Therefore, when preparing anti-oxidation coatings, using this material property can significantly improve the comprehensive function of the coating and meet the needs under extreme application conditions. In the selection of materials for cold spray powders, it is crucial to select materials with antioxidant properties, high melting points, and excellent heat resistance. These characteristics ensure that the coating can maintain long-term stability and effectiveness under high temperature, oxidizing environments, and extreme working conditions. The anti-oxidation property prevents the coating from oxidative failure in high temperature environments, the high melting point ensures that the coating does not melt or soften at extreme temperatures, and the heat resistance ensures that the coating can withstand continuous thermal cycles and temperature changes without causing structural damage due to thermal stress. By selecting these materials with high temperature stability, the durability, bonding strength and overall performance of the coating can be significantly improved to meet the application requirements in high temperature and high oxidation environments.

[0046] Step 4, cold spraying to form an anti-oxidation coating on the brazing material coating on the surface of the C / C composite material;

[0047] The composite powder is sprayed on the brazing material coating on the surface of the C / C composite material by cold spraying technology to form an anti-oxidation coating.

[0048] Specifically, during the cold spraying process: the working gas is nitrogen or helium, the distance between the brazing material coating on the surface of the C / C composite material and the spray gun is 15 to 25 cm, the carrier gas temperature is 300 to 600°C, the carrier gas pressure is 2 to 4 MPa, the spray gun moving speed is 100 to 300 mm / min, and the powder feeding rate is 100 to 180 g / min.

[0049] And the cold spraying preparation method of the anti-oxidation coating on the surface of the C / C composite material of the present invention is described in combination with Example 1 and Example 2:

[0050] Example 1

[0051] 1. Pretreatment stage: prepare the C / C composite material matrix, and process the C / C composite material matrix into the required shape and size, cut the AgCuTi solder foil with a thickness of 50 μm according to the size and shape of the C / C composite material matrix, and ensure that the AgCuTi solder foil can completely cover the surface of the C / C composite material matrix.

[0052] 2. Brazing experiment to form a brazing coating: The brazing temperature is set according to the melting point of the AgCuTi brazing foil, that is, the brazing temperature in this embodiment is higher than the melting point of the brazing foil brazing material to ensure that the brazing material can be fully melted and flowed, and the brazing temperature is 900°C; the high entropy alloy brazing foil is placed close to the surface of the C / C composite material, and it is placed in a vacuum brazing furnace, and the temperature is increased from room temperature to the brazing temperature at a heating rate of 15°C / min for vacuum brazing reaction, and then cooled to room temperature at a cooling rate of 5°C / min to achieve a uniform and continuous AgCuTi brazing coating on the surface of the C / C composite material. The SEM image of the interface reaction between the AgCuTi brazing coating and the C / C composite material matrix is ​​shown in FIG. Figure 2 shown.

[0053] 3. Prepare cold spray powder: Use a grading screen to sieve the powder raw material to obtain a uniform particle size, and select cold spray powder with a particle size of 10 to 45 μm; in this embodiment, nickel powder and chromium powder are selected as cold spray powder, and the nickel powder and chromium powder are evenly mixed in a ratio of 1:1 to form a NiCr composite powder for an antioxidant coating.

[0054] 4. Cold spray preparation of anti-oxidation coating: The anti-oxidation NiCr coating was sprayed on the surface of the pretreated C / C composite material by cold spraying technology. The working gas during the cold spraying process was nitrogen. The distance between the solder coating on the surface of the C / C composite material and the spray gun was 20 cm, the carrier gas temperature was 500 ° C, the carrier gas pressure was 3.2 MPa, the spray gun moving speed was 200 mm / min, and the powder feeding rate was 120 g / min. The SEM image of the cross section of the anti-oxidation NiCr coating formed on the AgCuTi solder coating of the C / C composite matrix is ​​shown in Figure 4. Figure 3 shown.

[0055] from Figure 2 It can be seen that the AgCuTi solder coating is evenly coated on the surface of the C / C composite material and is tightly bonded to the interface of the C / C composite material; a continuous TiC reaction layer appears in the interface area close to the C / C composite material, indicating that the active Ti element in the solder chemically reacts with the C / C composite material to form a new phase, which helps to enhance the bonding strength of the interface; Figure 3 It can be concluded that an obvious interface structure can be observed in the bonding area of ​​the AgCuTi solder coating and the NiCr coating, indicating that the cold spraying technology successfully deposited the anti-oxidation NiCr coating on the C / C composite material. That is, the anti-oxidation NiCr coating prepared in Example 1 forms a good mechanical bite and metallurgical bond on the surface of the C / C composite material substrate with the AgCuTi solder coating, and can effectively block oxygen in a high temperature environment.

[0056] Example 2

[0057] 1. Pretreatment stage: prepare the C / C composite material matrix, and process the C / C composite material matrix into the required shape and size, cut the AgCu solder foil with a thickness of 50 μm according to the size and shape of the C / C composite material matrix, and ensure that the AgCu solder foil can completely cover the surface of the C / C composite material matrix.

[0058] 2. Brazing experiment to form a brazing coating: The brazing temperature is set according to the melting point of the AgCu brazing foil, that is, the brazing temperature in this embodiment is higher than the melting point of the brazing foil brazing material to ensure that the brazing material can be fully melted and flowed, and the brazing temperature is 850°C; the high entropy alloy brazing foil is placed close to the surface of the C / C composite material, and it is placed in a vacuum brazing furnace, and the temperature is increased from room temperature to the brazing temperature at a heating rate of 15°C / min for vacuum brazing reaction, and then cooled to room temperature at a cooling rate of 5°C / min to achieve a uniform and continuous AgCu brazing coating on the surface of the C / C composite material. The SEM image of the interface reaction between the AgCu brazing coating and the C / C composite material matrix is ​​shown in FIG. Figure 4 shown.

[0059] 3. Prepare cold spray powder: Use a grading sieve to sieve the powder raw material to obtain a uniform particle size, and select cold spray powder with a particle size of 10 to 45 μm; In this embodiment, Al2O3-Al powder (Al2O3 10at%) is selected as the raw material for the antioxidant cold spray coating, mainly based on its excellent melting point, heat resistance and thermal stability. Al2O3 has an extremely high melting point (about 2072°C) and excellent chemical stability. It can form a dense protective film in a high temperature environment, effectively blocking the penetration of oxygen and other oxidizing gases. Aluminum (Al) has a low melting point (660°C), but it can be quickly oxidized at high temperatures to form an Al2O3 layer. This in-situ generated oxide film has self-healing properties, can repair local damage, and further enhance antioxidant capacity.

[0060] 4. Cold spray preparation of anti-oxidation coating: The anti-oxidation Al2O3-Al coating was sprayed on the surface of the pretreated C / C composite material by cold spraying technology. The working gas during the cold spraying process was nitrogen. The distance between the solder coating on the surface of the C / C composite material and the spray gun was 20 cm, the carrier gas temperature was 500 ° C, the carrier gas pressure was 3.2 MPa, the spray gun moving speed was 200 mm / min, and the powder feeding rate was 120 g / min. The SEM image of the cross section of the anti-oxidation Al2O3-Al coating formed on the AgCu solder coating on the C / C composite substrate is shown in Figure 4. Figure 5 shown.

[0061] Figure 5The SEM image of the cross section of the oxidation-resistant Al2O3-Al coating formed on the AgCu solder coating on the C / C composite substrate. During the cold spraying process, the metal-based composite powder (Al2O3-Al) impacts the pretreated C / C composite substrate at a very high speed driven by the supersonic gas flow. Due to the high-speed impact of the particles, the Al powder undergoes severe plastic deformation, spreads on the surface of the substrate and accumulates tightly to form a dense metal coating. At the same time, the Al2O3 particles, as a hard phase, are embedded in the interface between the substrate and the coating during the impact process, which has a tamping effect, which further enhances the mechanical strength of the coating.

[0062] The Al2O3-Al anti-oxidation coating prepared by cold spraying technology is not only successfully deposited on the AgCu brazing filler metal coating, achieving good mechanical bonding with the C / C composite matrix, but also forms a protective layer with excellent anti-oxidation properties through the efficient deposition of metal-based composite powders and multiphase synergy, providing reliable guarantee for the application of C / C composites in high temperature and harsh environments.

[0063] Performance Testing:

[0064] The oxidation weight gain per unit area (Δm) is used to evaluate the mass increase per unit surface area of ​​the material during the oxidation process and is used to characterize the anti-oxidation performance of the coating. By measuring the increase in mass per unit surface area during the oxidation process, the degree of reaction between oxygen or other oxidizing substances and the coating surface can be quantified. For anti-oxidation coatings, a lower Δm value indicates that the coating can effectively block the penetration of oxygen or corrosive gases, and the material has relatively excellent anti-oxidation performance under this condition. The calculation formula for the oxidation weight gain per unit area Δm is:

[0065]

[0066] Among them, m n is the mean weight of the sample after the oxidation cycle (mg); m n-1 is the average weight of the sample before the oxidation cycle (mg); S is the total surface area of ​​the sample (mm 2 ).

[0067] Oxidation rate constant (k p ) is usually calculated based on the parabolic growth law, in which the square of the mass change is proportional to time. This constant quantifies the oxidation rate of the coating at a specific temperature and oxidation environment. The formula is as follows:

[0068]

[0069] Among them, k p is the oxidation rate constant, in mg 2 / (cm 4 h); Δ(m / S) 2It is the square of the change in mass per unit area, usually expressed as (mg / cm 2 ) 2 Δ represents the time change, in hours (h). The smaller the oxidation rate constant value, the slower the oxidation reaction of the coating, and the better the anti-oxidation performance of the coating.

[0070] In the specific experimental design, the anti-oxidation cold spray coating samples with a size of 5mm×5mm×3mm were prepared by wire cutting equipment, and the oxidation experiment was carried out in the OTF-1200X tube furnace. The test temperature was set to 500℃, the heating rate was 10℃ / min, the experimental time was gradually extended from 10 hours to 60 hours, and the oxidation weight gain of the samples was recorded at 6 time points. The experimental results were used to calculate the oxidation weight gain per unit area (Δm) and the oxidation rate constant (k p ), so as to comprehensively evaluate the anti-oxidation performance of the cold sprayed coating. In 60 hours, the unit area weight gain (Δm) of the cold sprayed NiCr coating and Al2O3-Al coating was 48.0 mg / cm 2 and 51.3 mg / cm 2 .

[0071] Generally, the oxidation kinetics curve shows a high oxidation rate at the beginning of the experiment, which then gradually decreases and eventually stabilizes. This curve change reflects that an oxide film is quickly formed on the coating surface at the beginning, which then gradually thickens and stabilizes, effectively blocking further contact between oxygen and the coating material, thereby significantly reducing the oxidation rate.

[0072] Oxidation kinetic curves of NiCr and Al2O3-Al cold spray coatings are shown in Figure 6 As shown. For NiCr coating, the experiment shows that the calculated value of the oxidation rate constant is 22.5 mg 2 / (cm 4 ·h), which indicates that after the oxide film is formed, the oxidation process gradually enters a stable stage controlled by diffusion. The oxidation resistance of NiCr coating mainly depends on the presence of chromium. Under high temperature conditions, the Cr2O3 oxide film generated by the reaction of chromium and oxygen is dense and stable, which can provide effective high-temperature oxidation protection for the C / C composite substrate. Similarly, the oxidation rate constant of Al2O3-Al coating is 5.32mg 2 / (cm 4 h), showing similar oxidation behavior. At high temperatures, Al2O3 is formed on the surface of the coating. 氧Due to the excellent chemical stability of aluminum oxide, this oxide film can effectively prevent oxygen from penetrating, thereby controlling and slowing down the further oxidation of the coating. The formation of Al2O3 oxide film is essential to maintaining the integrity and function of the coating, especially under conditions of continuous exposure to high temperature and oxidizing environment.

[0073] The oxidation weight gain per unit area (Δm) and the oxidation rate constant (k p ) conducted an in-depth analysis of the protective effect of cold spray coatings in high-temperature oxidizing environments, providing important data support and theoretical basis for the design optimization and practical application of coatings.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cold spraying method for preparing an anti-oxidation coating on the surface of a C / C composite material, characterized in that: include: preparing a C / C composite material matrix and a high entropy alloy brazing foil having the same size as the C / C composite material matrix; A high entropy alloy brazing material foil is attached to the surface of a C / C composite material substrate, and the C / C composite material attached with the high entropy alloy brazing material foil is subjected to a vacuum brazing reaction to obtain a welding brazing material coating formed on the C / C composite material substrate; Prepare cold spray powder with uniform particle size, obtain the mass ratio or volume ratio of each component in the anti-oxidation coating to be prepared according to the atomic ratio of the anti-oxidation coating to be prepared; according to the mass ratio or volume ratio of each component, mix the components of the anti-oxidation coating to be prepared according to the atomic ratio to form a composite powder of the anti-oxidation coating; The composite powder is sprayed on the brazing material coating on the surface of the C / C composite material by cold spraying technology to form an anti-oxidation coating.

2. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 1, characterized in that: The high entropy alloy solder foil is one of AgCuTi solder foil, NiCrSi solder foil, AgCuSn solder foil, NiTi solder foil, CuTi solder foil, CoTi solder foil, TiZrNiCu solder foil and BNi2 solder foil.

3. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 1, characterized in that: The thickness of the high entropy alloy solder foil is 50 to 150 μm.

4. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 1, characterized in that: The steps of obtaining the solder coating formed on the C / C composite material substrate are as follows: Set the brazing temperature according to the high entropy alloy brazing foil; The C / C composite material substrate with the high entropy alloy brazing foil is subjected to vacuum brazing reaction from room temperature to brazing temperature at a preset heating rate, and is kept warm for a set holding time; After the insulation is completed, the material is cooled to room temperature at a preset cooling rate to prepare a welding brazing material coating on the surface of the C / C composite material matrix.

5. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 4, characterized in that: The brazing temperature is 800-1300°C, the holding time is 10-120min, the heating rate is 1-20°C / min, and the cooling rate is 1-20°C / min.

6. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 1, characterized in that: The cold spray powder raw material is sieved by using a grading screen to obtain cold spray powder with uniform particle size, wherein the particle size of the cold spray powder is 10 to 45 μm.

7. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 1, characterized in that: Cold spray powders include powders made of any two of nickel, titanium, cobalt, chromium, iron, nickel-based alloys, titanium alloys, cobalt alloys, chromium alloys, and iron alloys.

8. The cold spraying preparation method of the anti-oxidation coating on the surface of a C / C composite material according to claim 1, characterized in that: During the cold spraying process: the working gas is nitrogen or helium, the distance between the brazing material coating on the surface of the C / C composite material and the spray gun is 15-25 cm, the carrier gas temperature is 300-600°C, the carrier gas pressure is 2-4 MPa, the spray gun moving speed is 100-300 mm / min, and the powder feeding rate is 100-180 g / min.

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