Coating-substrate modified integrated c / c-w-cu composite material and preparation method thereof

Abstract

The application discloses a coating-substrate modification integrated C / C-W-Cu composite material and a preparation method, and belongs to the technical field of super-high-temperature composite materials. The composite material comprises, from top to bottom, a surface coating, a modified substrate layer and a substrate layer; the surface coating is a W-Cu composite coating, the modified substrate layer is a modified C / C-W-Cu substrate layer, and the substrate layer is a C / C substrate layer; the interface between the surface coating and the modified substrate layer is of a gradient structure, and the interface between the modified substrate layer and the substrate layer is of a pinning structure. A proper amount of W-Cu metal material is introduced into the C / C composite material, the metal modified C / C composite material is adopted, the coating-substrate modification integrated design is adopted, and a dense protective coating is prepared on the surface of the sample, so that the problems that the density of a single refractory metal material is too high to meet the lightweight design requirement, the super-high-temperature ceramic modification component has great brittleness and low fracture toughness, the surface of the substrate modification sample has many defects and is prone to cracks under the impact of high-speed particles, and the single coating and the substrate have great difference in thermophysical properties and are prone to peeling at high temperatures are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ultra-high temperature composite materials, and particularly relates to a coating-substrate modified integrated C / C-W-Cu composite material and a preparation method. BACKGROUND

[0002] As a kind of leading technology equipment, high-speed aircraft has become a research hotspot in the field of aerospace. Among them, missile as a kind of rapid penetration weapon, has super offensive and deterrent, is an important pillar to maintain strategic balance. In order to realize its high mobility, currently mainly adopts gas rudder to control the missile thrust vector, the system adjusts the deflection of gas rudder by installing control vane at the outlet of engine nozzle, so as to change the direction of gas jet. However, the vane will be in high temperature and high speed gas jet atmosphere during the whole working process, which puts forward new challenges to the high temperature ablation resistance and erosion resistance of the material.

[0003] Tungsten infiltrated copper material has excellent thermal shock resistance and candle resistance, and is the main material used in current gas rudder. However, tungsten infiltrated copper has large density and high quality, which will increase the weight of missile and reduce its working efficiency, and the material mainly relies on tungsten skeleton to bear, so it is difficult to reduce weight by reducing tungsten content. C / C composite material is a carbon-based composite material with carbon fiber as reinforcing material, which has low density, high specific strength / modulus, excellent thermal shock resistance and many other characteristics, and is also one of the commonly used materials for gas rudder. However, C / C composite material has strong high temperature oxidation sensitivity and weak erosion resistance, and is obviously damaged in high temperature and high speed gas jet atmosphere. Therefore, improving the erosion resistance of C / C composite material has become an important direction for the lightweight development of gas rudder.

[0004] Currently, the methods for improving the ablation resistance and erosion resistance of C / C composites mainly include coating technology and matrix modification technology. In the aspect of coating protection, the existing literature "Zhang Pei. Study on SiC-HfB2-based oxidation / ablation coating prepared by slurry coating combined with vapor silicon infiltration[D]. Doctoral dissertation of Northwestern Polytechnical University, 2022: 120-121." proposes to use slurry coating combined with vapor silicon infiltration to prepare HfB2-SiC gradient coating, and its linear ablation rate is reduced by 4.9% compared with pure C / C composite in the solid rocket engine plume test environment ablation test, but there is a significant coating peeling phenomenon, which shows that the gradient coating still needs to be further improved for the ablation resistance of C / C composite in the solid rocket engine plume. In the aspect of matrix modification technology, the existing literature "Y. Liu, Q. Fu, B. Wang, Y. Guan, Y. Liu Ablation behavior of C / C-SiC-ZrB2 composites in simulated solid rocket motor plumes[J]. Journal of Alloys and Compounds. 727 (2017) 135-145." proposes to use reaction infiltration method to prepare C / C-SiC-ZrB2 composite, after ablation test in the solid rocket engine plume environment, the front sample is subjected to catastrophic damage, its length is greatly reduced, under the action of impact load, the carbon fibers near the impact point are broken, the ceramic matrix is crushed, a large number of fiber and matrix fragments are formed, and the synergistic effect of oxidation and mechanical erosion of solid rocket engine plume leads to rapid failure of the composite.

[0005] In summary, the existing technology has the problems of high density of single refractory metal material, which is difficult to meet the lightweight design requirements, high brittleness and low fracture toughness of superhigh temperature ceramic modification components, many surface defects of matrix modification samples and easy to produce cracks under high-speed particle impact, and large difference in thermophysical properties between single coating and matrix and easy to peel off at high temperature. SUMMARY

[0006] In order to overcome the above-mentioned defects of the prior art, the purpose of the present application is to provide a coating-substrate modification integrated C / C-W-Cu composite material and a preparation method, which introduces an appropriate amount of W-Cu metal material into the C / C composite material, avoids the problem that the single refractory metal material has too high density to meet the lightweight design requirement, adopts the metal modified C / C composite material to avoid the problems of large brittleness and low fracture toughness of the super-high temperature ceramic modification component, adopts the coating-substrate modification integrated design to prepare a dense protective coating on the surface of the sample, solves the problems of many surface defects of the substrate modification sample and easy crack under high-speed particle impact, adopts the slurry brushing combined with the reaction infiltration to prepare the coating-substrate modification integrated C / C-W-Cu composite material, alleviates the difference in thermal physical properties between the coating and the substrate, and has low cost, simple operation, short preparation period, high controllability and suitability for large-scale production.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] The present application provides a coating-substrate modification integrated C / C-W-Cu composite material, which comprises a surface coating layer, a modified substrate layer and a substrate layer arranged in sequence from top to bottom.

[0009] In the specific implementation process, the interface between the surface coating layer and the modified substrate layer has a gradient structure, and the interface between the modified substrate layer and the substrate layer forms a pinning structure.

[0010] In the specific implementation process, the modified substrate layer can provide the surface coating layer with a sweating agent Cu at high temperature.

[0011] In the specific implementation process, the W-Cu composite coating is composed of metal W and metal Cu.

[0012] The metal W accounts for 80% of the total volume fraction of the W-Cu composite coating, and the metal W serves as a skeleton structure.

[0013] The metal Cu is distributed in the grain gap of the metal W.

[0014] The present application further provides a preparation method of the coating-substrate modification integrated C / C-W-Cu composite material, which comprises the following steps:

[0015] After the low-density C / C composite material is cut, polished and ultrasonically cleaned and dried, a pretreated low-density C / C composite material is obtained.

[0016] The deionized water and the binder are heated and stirred uniformly in a water bath to obtain a binder solution; the W powder is added to the binder solution and stirred uniformly to obtain a slurry suspension solution;

[0017] The slurry suspension solution is uniformly brushed on the surface of the pretreated low-density C / C composite material, and drying is performed once for each brushing to form a pre-coating layer; the process is repeated several times until the target thickness of the pre-coating layer is reached, and a low-density C / C composite material with a pre-coating layer is obtained;

[0018] The WO3 powder, the Cu powder, the NaCl powder and the KCl powder are mixed and subjected to ball milling to obtain a mixed powder; the mixed powder is sieved and dried to obtain a sintering powder;

[0019] A layer of the sintering powder, the low-density C / C composite material with the pre-coating layer and a layer of the sintering powder are sequentially laid from bottom to top to obtain an intermediate material;

[0020] The intermediate material is subjected to heat treatment and then cooled to obtain a coating-substrate modified integrated C / C-W-Cu composite material.

[0021] In the specific implementation process, the low-density C / C composite material is a 2.5D C / C composite material with a density of 1.1-1.5 g / cm 3 .

[0022] In the specific implementation process, the binder is polyvinyl alcohol solid particles; and the concentration of the polyvinyl alcohol in the binder solution is 2-10 wt%.

[0023] In the specific implementation process, the temperature of the water bath heating and stirring is greater than 90℃, and the time of the water bath heating and stirring is 0.5-2 h.

[0024] In the specific implementation process, the mass ratio of the W powder to the binder solution is 3:1.

[0025] In the specific implementation process, the WO3 powder and the Cu powder form a WO3-Cu mixed powder; and the NaCl powder and the KCl powder form a NaCl-KCl mixed powder.

[0026] The mass ratio of the WO3 powder to the Cu powder is 1:1; and the mass ratio of the NaCl powder to the KCl powder is 1:1.

[0027] The mass ratio of the WO3-Cu mixed powder to the NaCl-KCl mixed powder is (10-30):1.

[0028] In the specific implementation process, the heat treatment is performed as follows:

[0029] The temperature is raised to 1300-1400℃ at a temperature raising rate of 5℃ / min in a vacuum environment, and the temperature is kept for 2 h.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application provides a coating-substrate modification integrated C / C-W-Cu composite material, the surface of which is a composite metal coating composed of refractory metal W with high melting point and low saturated vapor pressure and sweating metal Cu with low melting point and high phase change enthalpy, the inside of a certain thickness range is W-Cu modified C / C composite material, and the remaining part is unmodified C / C composite material. The W-Cu composite coating in the above composite material can improve the erosion resistance of C / C composite material in high-speed particle impact environment, and can also reduce the surface temperature of the material by absorbing heat with the sweating material in high temperature environment, thereby improving the oxidation and ablation resistance of the material. In addition, the introduction of a proper amount of W-Cu metal in a specific area inside the C / C composite material forms a modified C / C-W-Cu substrate layer, so that the overall density of the material is controlled at a low level, solving the problem that the density of single refractory metal material is too high to meet the lightweight design requirements. The use of metal instead of ultra-high temperature ceramic to modify the C / C composite material avoids the problems of large brittleness and low fracture toughness of the ultra-high temperature ceramic modification components. Through the coating-substrate modification integrated design, a dense protective coating is prepared on the surface of the sample, which not only solves the problems of many surface defects of single substrate modified sample and easy cracking under high-speed particle impact, but also relieves the difference in thermal physical properties between the coating and the substrate, to a certain extent, overcoming the problem of easy peeling of the coating at high temperature due to the large thermal mismatch between the coating and the substrate.

[0032] The present application also provides a preparation method of coating-substrate modification integrated C / C-W-Cu composite material, which coats metal W on the surface of the substrate by a simple slurry method, and the Cu in the melt actively fills the residual pores under the action of capillary force in the subsequent melting process, and the melt can penetrate the porous coating and enter the inside of the substrate to react with the C / C composite material within a certain range to form a modified C / C-W-Cu substrate layer. The coating has high density, is tightly combined with the substrate, and the thermal mismatch is relieved, the operation is simple, and the large-scale industrial application can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Figure 1 is a cross-sectional SEM image of the gradient structure coating-substrate modification integrated C / C-W-Cu composite material prepared by the present application, wherein figure (a) is a macroscopic photograph of the composite material with a coating thickness of about 1 mm and a modified thickness of about 2 mm, figure (b) is an enlarged view of the coating, figure (c) is a microstructure of the coating, and figure (d) is an enlarged view of the coating-substrate interface;

[0034] Figure 2The contrast chart of optical photos and erosion rates of the unmodified C / C composite material and the gradient structure coating-substrate modified integrated C / C-W-Cu composite material after particle impact; wherein, Fig. (a) is the optical photo of the unmodified C / C composite material after particle impact, Fig. (b) is the optical photo of the coating-substrate modified integrated C / C-W-Cu composite material after particle impact; Fig. (c) is the contrast chart of mass erosion rate and linear erosion rate of the two kinds of composite materials after particle impact. DETAILED DESCRIPTION

[0035] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the text are of the usual meaning understood by those skilled in the art of the present application, and in case of conflict, the definition in the specification shall prevail.

[0036] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.

[0037] Herein, all features defined in the form of numerical ranges or percentage ranges such as values, amounts, contents and concentrations are for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual values within the range (including integers and fractions).

[0038] Herein, unless otherwise specified, “comprise”, “include”, “contain”, “have” or similar words encompass the meaning of “consist of” and “consist essentially of”, for example, “A comprises a” encompasses the meaning of “A comprises a and other” and “A comprises only a”.

[0039] Herein, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope disclosed in the specification.

[0040] The present application provides a coating-substrate modified integrated C / C-W-Cu composite material and a preparation method.

[0041] The first aspect of the present application provides a coating-substrate modified integrated C / C-W-Cu composite material, which comprises a surface coating, a modified substrate layer and a substrate layer arranged from top to bottom; the surface coating is a W-Cu composite coating, the modified substrate layer is a modified C / C-W-Cu substrate layer, and the substrate layer is a C / C substrate layer; wherein the modified substrate layer can provide sweat Cu for the surface coating at high temperature; the W-Cu composite coating is composed of metal W and metal Cu; the metal W accounts for 80% of the total volume fraction of the W-Cu composite coating, the metal W serves as a skeleton structure, and the metal Cu is distributed in the grain gap of the metal W.

[0042] The interface between the surface coating and the modified substrate layer has a gradient structure, and the distribution of the gradient elements helps to reduce the difference in thermophysical properties between the coating and the substrate, realize smooth transition of the coating and the substrate, and avoid cracking and peeling of the coating and the substrate due to thermal mismatch at high temperature; a pinning structure is formed at the interface between the modified substrate layer and the substrate layer, and the zigzag interface structure can inhibit the generation and expansion of transverse cracks in the two substrates due to thermal stress.

[0043] Figure 1 The present application provides a gradient structure coating-substrate modified integrated C / C-W-Cu composite material; wherein, figure (a) is a macroscopic photograph of the prepared composite material with a coating thickness of about 1 mm and a modified thickness of about 2 mm, the surface layer of which is a dense W-Cu composite coating for resisting high-temperature high-speed gas / particle flow erosion in extreme environments; the coating below is the modified C / C-W-Cu substrate, which not only provides sweat Cu for the surface coating at high temperature, but also improves the bonding strength of the coating and the substrate by introducing the same metal components as the coating, and alleviates the problem of mismatching of the thermal expansion coefficients of the coating and the substrate; the bottom is the unmodified C / C composite material, which has a density much lower than the metal modified components, and can reduce the overall density of the material; figure (b) is an enlarged view of the coating, from which it can be seen that the coating is composed of a white phase and a gray phase, wherein the white phase is metal W and the gray phase is metal Cu, the white phase accounts for about 80% of the total volume fraction of the coating, forming a skeleton structure, which helps to realize high-temperature high-speed particle impact protection; figure (c) is a microstructure of the coating, which shows that the gray phase Cu is distributed in the grain gap of the white phase W, and the grain size of W is about 5 μm; figure (d) is an enlarged view of the coating-substrate interface, which shows that the coating and the substrate are tightly bonded without defects.

[0044] Figure 2Figure 1 is a contrastive diagram of optical photos and erosion rates of the unmodified C / C composite material and the gradient structure coating-substrate modified integrated C / C-W-Cu composite material after particle impact; wherein, figure (a) is an optical photo of the unmodified C / C composite material after particle impact, figure (b) is an optical photo of the coating-substrate modified integrated C / C-W-Cu composite material after particle impact, by comparing the optical photos of the surfaces after impact, it can be found that the C / C composite material forms large erosion pits on the surface after impact, while the modified sample has no obvious change in macroscopic morphology after impact; figure (c) is the mass erosion rate and linear erosion rate of the composite material after impact, the erosion rate of the C / C composite material is extremely high, while the erosion rate of the modified sample is maintained at a low level, the mass erosion rate and linear erosion rate are reduced by more than 99% compared with the unmodified C / C composite material, indicating that the sample is weakly damaged by impact and can effectively resist high-speed particle impact.

[0045] The second aspect of the present application provides a preparation method of a coating-substrate modified integrated C / C-W-Cu composite material, comprising the following steps:

[0046] The low-density C / C composite material is cut, polished and dried after ultrasonic cleaning to obtain a pretreated low-density C / C composite material; wherein, the low-density C / C composite material is a 2.5D C / C composite material with a density of 1.1-1.5 g / cm 3

[0047] The deionized water and the binder are heated and stirred uniformly in a water bath to obtain a binder solution; W powder is added to the binder solution and stirred uniformly to obtain a slurry suspension solution; the binder is preferably polyvinyl alcohol solid particles, and the concentration of polyvinyl alcohol in the binder solution is 2-10 wt%; the mass ratio of W powder to binder solution is 3:1;

[0048] The slurry suspension solution is uniformly brushed on the surface of the pretreated low-density C / C composite material, and drying is performed once for each brushing to form a pre-coating; the process is repeated several times until the target thickness of the pre-coating is reached to obtain a low-density C / C composite material with a pre-coating;

[0049] The WO3 powder, Cu powder, NaCl powder and KCl powder are mixed and ball milled to obtain a mixed powder; the mixed powder is sieved and dried to obtain a sintering powder; wherein, the WO3 powder and the Cu powder form a WO3-Cu mixed powder; the NaCl powder and the KCl powder form a NaCl-KCl mixed powder; the mass ratio of the WO3-Cu mixed powder to the NaCl-KCl mixed powder is (10-30):1; the WO3 powder and the Cu powder in the WO3-Cu mixed powder are equal in mass; the NaCl powder and the KCl powder in the NaCl-KCl mixed powder are equal in mass;

[0050] ​A layer of infiltrated powder, a low-density C / C composite material with a pre-coating layer and a layer of infiltrated powder are sequentially laid from bottom to top to obtain an intermediate material;

[0051] The intermediate material is subjected to heat treatment, i.e., heating to 1300-1400℃ at a heating rate of 5℃ / min in a vacuum environment, holding for 2h, and then cooling to obtain a coating-substrate modified integrated C / C-W-Cu composite material.

[0052] The specific steps of the preparation method are as follows:

[0053] Step 1: The low-density C / C composite material is cut and polished by a sand disc, cleaned by ultrasonic deionized water, and then dried in an oven at 70℃;

[0054] The low-density C / C composite material is a 2.5D C / C composite material with a density of 1.1-1.5g / cm 3 ;

[0055] Step 2: The solvent and the binder are weighed in a certain proportion and poured into a beaker, heated in a water bath and continuously stirred to obtain a uniform binder solution, and then a certain amount of W powder is poured into the solution, and a uniform slurry suspension solution is prepared by ultrasonic and magnetic stirring;

[0056] The solvent is deionized water, and the binder is polyvinyl alcohol solid particles; the polyvinyl alcohol concentration in the binder solution is 2-10wt.%;

[0057] The water bath heating temperature is greater than 90℃, and the heating and stirring time is 0.5-2h; the mass ratio of W powder to binder solution is 3:1;

[0058] Step 3: The slurry suspension solution is uniformly brushed on the surface of the pretreated low-density C / C composite material using a brush, and each brushing is followed by drying to form a pre-coating layer with a certain porosity.

[0059] The drying temperature is 70-90℃, and the drying time is greater than 30min; this step is repeated multiple times until the pre-coating layer thickness is met;

[0060] Step 4: A certain amount of WO3 powder, Cu powder, NaCl powder and KCl powder is weighed and poured into a ball mill jar for 8h of ball milling treatment, the mixed powder is sieved with a screen and dried in an oven to obtain an infiltrated powder; the molar ratio of NaCl to KCl is 1:1; the mass ratio of WO3 to Cu is 1:1; the mass ratio of WO3-Cu mixed powder to NaCl-KCl mixed powder is (10-30):1;

[0061] Step 5: A layer of infiltration powder is laid on the graphite crucible, and the low-density C / C composite material coated with a pre-coating layer is placed on the powder. Then, the powder is added to the graphite crucible until the low-density C / C composite material is completely covered by the infiltration powder. After the powder is added, a graphite paper is placed on the powder, and then a carbon felt is placed on the graphite paper to seal the graphite crucible. Finally, a graphite cover is placed on the graphite crucible, and the graphite crucible is wrapped with a graphite paper.

[0062] Step 6: The treated crucible is placed in a heat treatment furnace and heated to 1300-1400℃ at a heating rate of 5℃ / min in a vacuum environment. After 2h of heat preservation, the power is turned off, and the crucible is naturally cooled to room temperature. Then, the gradient structure coating-substrate modified integrated C / C-W-Cu composite material is obtained.

[0063] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the present application after reading the content taught by the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0064] In the following examples, conventional instruments and equipment in the art are used. In the following examples, the experimental methods not specified in the specific conditions are generally carried out according to the conventional conditions or according to the conditions recommended by the manufacturer. In the following examples, various raw materials are used, unless otherwise specified, and the conventional commercially available products are used, which are of conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, “%” means weight percent, “parts” means weight parts, and the ratio means weight ratio.

[0065] Example 1:

[0066] Step 1: A 2.5D C / C composite material with a density of 1.1g / cm 3 is used. The C / C composite material is polished using a diamond sand disc, ultrasonically cleaned with deionized water for 0.5h, and then dried in a 70℃ oven for 12h for standby.

[0067] Step 2: Deionized water and polyvinyl alcohol particles are weighed according to a mass ratio of 98:2, and then poured into a beaker to prepare a binder solution with a concentration of 2wt.%. The beaker is placed in a 90℃ water bath and continuously stirred for 0.5h to obtain a uniform binder solution. A certain amount of W powder is weighed according to a mass ratio of 3:1 with the uniform binder solution, and then poured into the solution. After ultrasonic treatment for 30min, the mixture is placed in a magnetic stirrer and stirred for 2h to obtain a uniform slurry suspension solution.

[0068] Step 3: The slurry suspension solution was evenly brushed on the surface of the pretreated low-density C / C composite material using a brush. After each brushing, the brushed sample was placed in a 70°C oven for drying for 30 min. After multiple brushings, a pre-coating layer with porosity was formed.

[0069] Step 4: A certain amount of WO3 and Cu powder was weighed according to the mass ratio of WO3 to Cu of 1:1, and a certain amount of NaCl and KCl powder was weighed according to the molar ratio of NaCl to KCl of 1:1. The WO3-Cu mixed powder and the NaCl-KCl mixed powder were poured into a ball mill tank according to the mass ratio of 30:1. The rotation speed was set to 300 r / min. After 8 h of planetary ball milling, the mixed powder was placed in a 70°C oven for drying for 24 h to obtain infiltrated powder.

[0070] Step 5: The obtained infiltrated powder was evenly spread inside a graphite crucible, with a thickness of 5 mm. The low-density C / C composite material coated with the pre-coating layer was placed above the powder. The infiltrated powder was poured to completely cover the low-density C / C composite material coated with the pre-coating layer. Then, another 5 mm thick infiltrated powder was evenly spread. After the addition of the powder, two layers of graphite paper were placed above the powder, followed by a layer of carbon felt for sealing treatment. Finally, the graphite crucible was wrapped with graphite paper.

[0071] Step 6: The treated crucible was placed in a heat treatment furnace. The temperature was raised to 1300°C at a rate of 5°C / min in a vacuum environment, and the temperature was maintained for 2 h. The power was turned off, and the sample was naturally cooled to room temperature. The surface of the sample was polished with sandpaper to remove the residual melt, and a gradient structure coating-substrate modified integrated C / C-W-Cu composite material was obtained.

[0072] Example 2:

[0073] Step 1: A 2.5D C / C composite material with a density of 1.3 g / cm 3 was used. The sample was polished using a diamond sand disc and cleaned with deionized water for 0.5 h. Then, the sample was placed in a 70°C oven for drying for 12 h for standby.

[0074] Step 2: A binder solution with a concentration of 5 wt.% was prepared by weighing a certain amount of deionized water and polyvinyl alcohol particles according to the mass ratio of 95:5 and pouring them into a beaker. The beaker was placed in a 95°C water bath and continuously stirred for 0.5 h to obtain a uniform binder solution. A certain amount of W powder was weighed according to the mass ratio of W powder to uniform binder solution of 3:1 and poured into the solution. After ultrasonic treatment for 30 min, the sample was placed in a magnetic stirrer for stirring for 2 h to obtain a uniform slurry suspension solution.

[0075] Step 3: The above slurry suspension solution was evenly brushed on the surface of the pretreated low-density C / C composite material using a brush. After each brushing, the brushed sample was placed in an 80°C oven for drying for 30 min. After multiple brushings, a pre-coating layer with certain porosity was formed.

[0076] Step 4: A certain amount of WO3 and Cu powder was weighed according to a mass ratio of 1:1, and a certain amount of NaCl and KCl powder was weighed according to a molar ratio of 1:1. The WO3-Cu mixed powder and the NaCl-KCl mixed powder were poured into a ball mill tank according to a mass ratio of 30:1. The rotation speed was set to 300 r / min. After 8 h of planetary ball milling, the mixed powder was placed in a 70°C oven for drying for 24 h to obtain infiltration powder.

[0077] Step 5: The obtained infiltration powder was evenly spread inside a graphite crucible, with a powder thickness of 5 mm. The low-density C / C composite material coated with the pre-coating layer was placed above the powder. The infiltration powder was poured to completely cover the low-density C / C composite material coated with the pre-coating layer, and then a 5 mm thick layer of infiltration powder was evenly spread. After the powder was added, two layers of graphite paper were placed above the powder, followed by a layer of carbon felt for sealing treatment. Finally, a graphite cover was placed, and the graphite crucible was wrapped with graphite paper.

[0078] Step 6: The treated crucible was placed in a heat treatment furnace. The temperature was raised to 1300°C at a rate of 5°C / min in a vacuum environment, and the temperature was maintained for 2 h. The power was turned off, and the sample was naturally cooled to room temperature. The sample surface was polished with sandpaper to remove the residual melt, and a gradient structure coating-substrate modified integrated C / C-W-Cu composite material was obtained.

[0079] Example 3:

[0080] Step 1: A 2.5D C / C composite material with a density of 1.5 g / cm 3 was used. The sample was polished using a diamond sand disc, ultrasonically cleaned with deionized water for 0.5 h, and then placed in a 70°C oven for drying for 12 h for standby.

[0081] Step 2: A certain amount of W powder was weighed according to a mass ratio of 3:1, and then poured into the solution. After ultrasonic treatment for 30 min, the sample was placed in a magnetic stirrer for stirring for 1 h to obtain a uniform slurry suspension solution.

[0082] Step 3: The slurry suspension solution was evenly brushed on the surface of the pretreated low-density C / C composite material using a brush. After each brushing, the brushed sample was placed in a 90°C oven for drying for 30 min. After multiple brushings, a pre-coating layer with porosity was formed.

[0083] Step 4: A certain amount of WO3 and Cu powder was weighed according to the mass ratio of WO3 to Cu of 1:1, and a certain amount of NaCl and KCl powder was weighed according to the molar ratio of NaCl to KCl of 1:1. The WO3-Cu mixed powder and the NaCl-KCl mixed powder were poured into a ball mill tank according to the mass ratio of 20:1. The rotation speed was set to 300 r / min. After 8 h of planetary ball milling, the mixed powder was placed in a 70°C oven for drying for 24 h to obtain a infiltrated powder.

[0084] Step 5: The obtained infiltrated powder was evenly spread inside a graphite crucible, with a powder thickness of 5 mm. The low-density C / C composite material coated with the pre-coating layer was placed above the powder. The infiltrated powder was poured to completely cover the low-density C / C composite material coated with the pre-coating layer, and then a 5 mm thick infiltrated powder was evenly spread. After the powder was added, two layers of graphite paper were placed above the powder, followed by a layer of carbon felt for sealing treatment. Finally, a graphite cover was placed, and the graphite crucible was wrapped with graphite paper.

[0085] Step 6: The treated crucible was placed in a heat treatment furnace. The temperature was raised to 1300°C at a rate of 5°C / min in a vacuum environment, and the temperature was maintained for 2 h. The power was turned off, and the sample was naturally cooled to room temperature. The surface of the sample was polished with sandpaper to remove the residual melt, and a gradient structure coating-substrate modified integrated C / C-W-Cu composite material was obtained.

[0086] Example 4:

[0087] Step 1: A 2.5D C / C composite material with a density of 1.5 g / cm 3 was used. The sample was polished using a diamond sand disc, ultrasonically cleaned with deionized water for 0.5 h, and then placed in a 70°C oven for drying for 12 h for standby.

[0088] Step 2: A binder solution with a concentration of 10 wt.% was prepared by weighing a certain amount of deionized water and polyvinyl alcohol particles according to the mass ratio of 90:10 into a beaker, heating the beaker in a 95°C water bath, and continuously stirring for 2 h to obtain a uniform binder solution. A certain amount of W powder was weighed according to the mass ratio of W powder to uniform binder solution of 3:1, and then poured into the solution. After ultrasonic treatment for 30 min, the sample was placed in a magnetic stirrer for stirring for 2 h to obtain a uniform slurry suspension solution.

[0089] Step 3: The slurry suspension solution is evenly brushed on the surface of the pretreated low-density C / C composite material using a brush, and after each brushing, the brushed sample is placed in a 70 DEG C oven for drying for 60 min, and after multiple brushing, a pre-coating layer with a certain porosity is formed.

[0090] Step 4: A certain amount of WO3 and Cu powder is weighed according to the mass ratio of WO3 to Cu of 1:1, and a certain amount of NaCl and KCl powder is weighed according to the molar ratio of NaCl to KCl of 1:1, and the mixed WO3-Cu powder and the mixed NaCl-KCl powder are poured into a ball mill tank according to the mass ratio of 10:1, the rotation speed is set to 300 r / min, and the planetary ball mill is used for ball milling for 8 h, and then the mixed powder is placed in a 70 DEG C oven for drying for 24 h to obtain a sintered powder.

[0091] Step 5: The obtained sintered powder is evenly laid in the graphite crucible, the thickness of the powder is 5 mm, the low-density C / C composite material coated with the pre-coating layer is placed above the powder, the sintered powder is poured to completely cover the low-density C / C composite material coated with the pre-coating layer, and then the sintered powder with a thickness of 5 mm is evenly laid. After the powder is added, two layers of graphite paper are placed above the powder, and then a layer of carbon felt is placed above the graphite paper for sealing treatment, and finally a graphite cover is covered, and the graphite crucible is wrapped with graphite paper.

[0092] Step 6: The treated crucible is placed in a heat treatment furnace, and the temperature is raised to 1400 DEG C at a heating rate of 5 DEG C / min in a vacuum environment, and the temperature is kept for 2 h, the power is turned off, and the sample is taken out after natural cooling to room temperature. The surface of the sample is polished with sandpaper to remove the residual melt, and a gradient structure coating-substrate modification integrated C / C-W-Cu composite material is obtained.

[0093] The application provides a coating-substrate modification integrated C / C-W-Cu composite material and a preparation method, and aims to improve the high-temperature impact resistance of the C / C composite material. By introducing an appropriate amount of W-Cu metal material into the C / C composite material, the problem of high density of pure metal material which is difficult to meet the lightweight design requirement is avoided; the metal modified C / C composite material avoids the problem of large brittleness and low fracture toughness of the conventional super-high-temperature ceramic modification component; the coating-substrate modification integrated design solves the problem of many surface defects of the substrate modification sample and easy crack under high-speed particle impact; the gradient structure design is adopted, the rear end of the material is the unmodified low-density C / C composite material, the modified region can be designed according to the actual application requirement, and the overall density of the material is reduced under the premise of ensuring the service reliability. In addition, the slurry brushing combined with the reaction sintering is used to prepare the C / C-W-Cu composite material, which has the advantages of low cost, simple operation, short preparation period, high controllability and suitability for large-scale production.

[0094] The above merely illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A coating-matrix modified integrated C / C-W-Cu composite material, characterized in that, The composite material comprises, from top to bottom, a surface coating layer, a modified matrix layer and a matrix layer; the surface coating layer is a W-Cu composite coating layer, the modified matrix layer is a modified C / C-W-Cu matrix layer, and the matrix layer is a C / C matrix layer.

2. The coating-matrix modified integrated C / C-W-Cu composite material according to claim 1, characterized in that, The interface between the surface coating layer and the modified matrix layer has a gradient structure, and the interface between the modified matrix layer and the matrix layer has a pinning structure.

3. The coating-matrix modified integrated C / C-W-Cu composite material according to claim 1, characterized in that, The modified matrix layer can provide the surface coating layer with a sweat Cu at high temperature.

4. The coating-matrix modified integrated C / C-W-Cu composite material according to claim 1, characterized in that, The W-Cu composite coating layer is composed of metal W and metal Cu; The metal W accounts for 80% of the total volume fraction of the W-Cu composite coating layer, and the metal W serves as a skeleton structure; The metal Cu is distributed in the grain gap of the metal W.

5. A method for producing the coating-matrix modified integrated C / C-W-Cu composite material according to any one of claims 1 to 4, characterized in that The method comprises the following steps: The low-density C / C composite material is cut, polished, and ultrasonically cleaned and dried to obtain a pretreated low-density C / C composite material; the low-density C / C composite material is a 2.5D C / C composite material with a density of 1.1-1.5 g / cm 3 . After the deionized water and the binder are uniformly heated and stirred in a water bath, a binder solution is obtained; after the W powder is added to the binder solution and uniformly stirred, a slurry suspension solution is obtained; The slurry suspension solution is uniformly brushed on the surface of the pretreated low-density C / C composite material, and drying is performed once for each brushing, to form a pre-coating layer; the process is repeated several times until the target thickness of the pre-coating layer is reached, to obtain a low-density C / C composite material with a pre-coating layer; The WO3 powder, Cu powder, NaCl powder and KCl powder are mixed and ball milled to obtain a mixed powder; the mixed powder is sieved and dried to obtain a sintering powder; A layer of sintering powder, a low-density C / C composite material with a pre-coating layer and a layer of sintering powder are sequentially laid from bottom to top to obtain an intermediate material; The intermediate material is subjected to heat treatment and then cooled to obtain a coating-matrix modified integrated C / C-W-Cu composite material.

6. The method for preparing the integrated coating-matrix modification C / CW-Cu composite material according to claim 5, characterized in that, The binder is polyvinyl alcohol solid particles; the concentration of polyvinyl alcohol in the binder solution is 2-10 wt%; and the mass ratio of the W powder to the binder solution is 3:

1.

7. The method for preparing the integrated coating-matrix modification C / CW-Cu composite material according to claim 5, characterized in that, The temperature of the water bath heating and stirring is greater than 90℃, and the time of the water bath heating and stirring is 0.5-2 h.

8. The method for preparing the coating-matrix modified integrated C / CW-Cu composite material according to claim 5, characterized in that, The WO3 powder and the Cu powder form a WO3-Cu mixed powder; and the NaCl powder and the KCl powder form a NaCl-KCl mixed powder. The mass ratio of the WO3 powder to the Cu powder is 1:1; and the mass ratio of the NaCl powder to the KCl powder is 1:

1. The mass ratio of the WO3-Cu mixed powder to the NaCl-KCl mixed powder is (10-30):

1.

9. The method for preparing the coating-matrix modified integrated C / CW-Cu composite material according to claim 5, characterized in that, The heat treatment process is as follows: The temperature is raised to 1300-1400℃ at a heating rate of 5℃ / min in a vacuum environment, and the temperature is kept for 2 h.

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