HfC-SiC-HfSi2 modified C / C composite material with three-layer multiphase ceramic coating as well as preparation method and application of HfC-SiC-HfSi2 modified C / C composite material

Abstract

The invention discloses an HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating as well as a preparation method and application of the composite material. The composite material comprises the coating and a matrix, the coating is of a three-layer multi-phase composite structure, and the three-layer multi-phase composite structure is composed of a SiC outer layer, an HfC-HfSi2 middle layer and a SiC inner layer. The thickness of the coating ranges from 100 micrometers to 160 micrometers. The matrix is composed of a C / C composite material and an HfC-SiC-HfSi2 ceramic component; according to the composite material, a coating and a base body are tightly combined through a chemical reaction, and a coating-base body integrated structure is formed. The composite material is prepared through a one-step reaction infiltration method, the preparation period and cost are greatly reduced through the method, the prepared coating is of a multi-layer and multi-phase composite structure, and under the combined action of material structure upgrading and component optimization, the composite material has excellent high-temperature ablation resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature thermal protection composite material, and particularly relates to an HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating and a preparation method and application thereof. BACKGROUND

[0002] The high Mach number (≥5Ma) flight behavior of a hypersonic vehicle in the atmosphere can cause strong aerodynamic heating, resulting in rapid rise of the surface temperature to above 2000℃, and thus causing serious oxidation and ablation. The temperature of the internal flow path of a supersonic engine is even higher, and the hot end components such as the combustion chamber, nozzle, throat liner and the like face even more extreme mechanical and thermo-chemical conditions. As a traditional thermal protection material, C / C composite material has irreplaceable performance advantages in the field of aerospace thermal protection, with the advantages of low density (<2 g / cm 3 However, C / C composite material will be severely oxidized above 500℃, which limits its application in high-temperature oxygen-containing environments.

[0003] The main technical means to improve the high-temperature oxidation resistance of C / C composite material includes matrix modification technology, coating protection technology and coupling of the two. For service temperatures above 2000℃, the main method is to use ultra-high temperature ceramics (UHTCs) materials such as diborides, carbides and nitrides of transition metals (Zr, Hf, Ta, etc.) as matrix modifiers and oxidation-resistant coating components. UHTCs materials generally have an ultra-high melting point of above 3000℃, and the complex chemical bonding behavior creates high mechanical stiffness, high thermal conductivity and excellent oxidation and ablation resistance. Among them, HfC is considered to be one of the most effective modification components of C / C composite material due to its extremely outstanding high-temperature stability. Further, the introduction of SiC ceramic has been proved to further improve the oxidation and ablation resistance of C / C-HfC composite material, because its liquid phase oxidation product (SiO2) can heal pores and cracks. In addition, SiC can effectively alleviate the mismatch problem of the thermal expansion coefficient between C / C and HfC. Therefore, the HfC-SiC ceramic system has attracted widespread attention in the modification of C / C composite material.

[0004] However, the ablation performance of the C / C-HfC-SiC composite material under ultra-high temperature and long-time test environment is still unsatisfactory. On the one hand, there are exposed fibers on the surface of the C / C-HfC-SiC composite material, which are prone to form holes and cracks during ablation, and oxygen will enter the material through these defects to accelerate the oxidation of carbon fibers and the matrix; on the other hand, the Si supply capacity of the HfC-SiC system is insufficient, and the crack healing mechanism of the liquid phase SiO2 rapidly fails in the early stage of ablation, and the porous HfO2 is difficult to form a dense and stable protective layer. To solve the above problems, the following optimization strategies can be implemented, one is to couple the matrix modification technology and the coating protection technology to prepare HfC-SiC coating-matrix integrated modified C / C composite material, and the other is to add silicon-rich components in the HfC-SiC system. The preparation processes of introducing the matrix into the C / C composite material mainly include precursor impregnation and pyrolysis (PIP), slurry impregnation (SI) and reaction melt infiltration (RMI); and the processes of preparing the coating on the surface of the C / C composite material mainly include chemical vapor deposition (CVD), plasma spraying (PS) and embedding cementation (PC).

[0005] At present, in order to realize the preparation of the UHTCs coating-matrix integrated modified C / C composite material, a combination of multiple processes is usually required, thereby leading to a complex and time-consuming preparation process (TANG Z X, ZHOU Y M, LIU R Z, et al. Preparation and ablation behavior of a ZrB2-SiC coating-matrix integrated C / C composite. Journal of the European Ceramic Society, 2024, 44(5): 2998-3011). In addition, the multiple-step preparation process usually requires repeated heating and cooling of the sample, which can lead to the accumulation of thermal stress in the material, and further cause cracking at the coating-matrix interface and the decrease of the mechanical properties of the material. At present, there are few one-step efficient preparation methods for the UHTCs coating-matrix integrated modified C / C composite material reported. SUMMARY

[0006] In order to solve the above technical problems and realize the efficient and simple preparation of the UHTCs coating-matrix integrated modified C / C composite material, the present application proposes a one-step reaction melt infiltration method for preparing the UHTCs coating-matrix integrated modified C / C composite material.

[0007] According to a first aspect of the present application, a HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating is provided, the composite material comprising a coating and a matrix; The coating is a three-layer multiphase composite structure, which is composed of a SiC outer layer, a HfC-HfSi2 intermediate layer and a SiC inner layer; The thickness of the coating is 100-160 μm; The substrate is composed of a C / C composite material and a HfC-SiC-HfSi2 component; The composite material is tightly combined by the coating and the substrate through chemical reaction, forming a coating-substrate integrated structure; The HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating is prepared by a one-step reaction infiltration method.

[0008] According to the second aspect of the present application, a one-step reaction infiltration preparation method of a HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating is provided, which comprises the following steps: Step (1): The porous C / C composite material is cut into regular blocks of appropriate size, polished and ultrasonically cleaned, and then dried, weighed and recorded; Step (2): According to the mass of the porous C / C composite material in step (1), silicon hafnium alloy powder is weighed according to a certain mass ratio and placed in a graphite crucible, and the porous C / C composite material is placed above the silicon hafnium alloy powder; Step (3): According to the mass of the porous C / C composite material in step (1), carbon-silicon mixed powder is weighed according to a certain mass ratio and placed in the graphite crucible in step (2), and it is ensured that it is uniformly distributed around the silicon hafnium alloy powder without contacting each other; Step (4): The graphite crucible in step (3) is placed in a high-temperature device, vacuumized, and then the furnace body is heated to the required temperature and kept for a period of time, and then the furnace body is cooled to room temperature to obtain a HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating.

[0009] Further, the porous C / C composite material in step (1) is a 3D continuous carbon fiber reinforced carbon-based composite material, with a density of 1.2-1.4 g / cm 3 , and a porosity of 15-30%.

[0010] Further, the Hf / Si molar ratio of the silicon hafnium alloy powder in step (2) is 1:2; Further, the carbon-silicon mixed powder in step (3) is a mixture of Si powder and C powder, and the molar ratio of Si powder to C powder is 1:1.

[0011] Further, the particle size of the silicon-hafnium alloy powder in step (2) is 800-1200 nm.

[0012] Further, the mass ratio of the silicon-hafnium alloy powder to the porous C / C composite material in step (2) is (2-3):1.

[0013] Further, the mass ratio of the carbon-silicon mixed powder to the porous C / C composite material in step (3) is (0.2-0.5):1.

[0014] Further, the silicon-hafnium alloy powder in step (2) is placed below the porous C / C composite material, i.e., the two are in direct contact.

[0015] Further, the carbon-silicon mixed powder in step (3) is uniformly distributed around without contacting the porous C / C composite material and the silicon-hafnium alloy powder.

[0016] Further, the vacuum degree in step (4) is below 10 Pa. The heating rate of the vacuum furnace in step (4) is 5-10 ℃ / min, and the holding time is 30-60 min. The cooling rate in step (4) is 5-10 ℃ / min.

[0017] According to a third aspect of the present application, there is provided an application of the HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating in a high-temperature aerobic environment.

[0018] Compared with the prior art, the present application has the following advantages: (1) The present application provides an HfC-SiC-HfSi2 modified C / C composite material with a SiC / HfC-HfSi2 / SiC three-layer multiphase coating. In the three-layer multiphase coating, the outer layer SiC is rapidly oxidized at the initial stage of ablation, the liquid product SiO2 can heal surface cracks, and the subsequent evaporation loss can also absorb a large amount of heat to reduce the surface temperature; the main oxidation products of the intermediate layer HfSi2-HfC are solid HfO2 and liquid SiO2, and the HfO2 grains continuously grow in the liquid SiO2, while the SiO2 is consumed, a continuous HfO2 layer is formed, which becomes an effective barrier to block the diffusion of oxygen and the erosion of airflow; the inner layer SiC helps to alleviate the thermal mismatch between the coating and the substrate, and forms a strong bond between the coating and the substrate. Through the synergistic mechanism of multiple elements, the SiC / HfC-HfSi2 / SiC three-layer multiphase composite structure coating has more excellent ablation resistance than single-layer or single-phase coatings.

[0019] (2) The application further provides a one-step reaction infiltration preparation method of a C / C-HfC-SiC composite material with a three-layer multiphase ceramic coating. The method has the advantages of simplicity, high efficiency, low cost and integral manufacturing of complex heterogeneous structural parts, and not only greatly reduces the preparation period and cost of the coating-substrate integrated modified C / C composite material, significantly improves the interface bonding strength between the coating and the substrate, but also has a multi-layer and multi-phase composite structure. Under the combined action of material structure upgrading and component optimization, the high-temperature ablation resistance of the coating-substrate integrated modified C / C composite material is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 XRD patterns of the coating and the substrate of the composite material prepared in Example 1 of the application (a is the coating, and b is the substrate); Figure 2 A scanning electron microscope image of the composite material prepared in Example 1 of the application; Figure 3 A scanning electron microscope image of the composite material prepared in Example 2 of the application; Figure 4 A scanning electron microscope image of the composite material prepared in Comparative Example 1 of the application; Figure 5 A scanning electron microscope image of the composite material prepared in Comparative Example 2 of the application. DETAILED DESCRIPTION

[0021] The application will be further described below in combination with specific embodiments, but the application is not limited by any way.

[0022] Example 1 A preparation method of a HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating, comprising the following steps: (1) A porous C / C composite material (density: 1.25-1.30 g / cm 3 , porosity: 25-30 %) is cut into a rectangular block with a size of 70×35×10 mm, and then is polished by a sand disc, ultrasonically cleaned and vacuum dried (-0.1 Mpa, 80℃, 5 h) to obtain a block with a mass of 30.46 g; (2) 100 g of hafnium silicon alloy powder (purity ≥ 99.5 %, particle size 10 μm) is weighed, and is poured into a ball mill tank together with 200 ml of anhydrous ethanol, and is ball milled by a planetary ball mill for 12 h. Then the powder slurry is vacuum dried (-0.1 Mpa, 25℃, 10 h) to obtain 92 g of hafnium silicon alloy powder raw material with a particle size distribution of 800-1200 nm; (3) According to the molar ratio of carbon powder and silicon powder 1:1, 12 g of carbon powder (purity ≥ 99.9%, particle size 1-3 μm) and 28 g of silicon powder (purity ≥ 99.9%, particle size 1-3 μm) were weighed and poured into a ball mill tank together with 80 ml of anhydrous ethanol. The mixture was ball milled for 6 h by a planetary ball mill, and then the mixed powder slurry was vacuum dried (-0.1 Mpa, 25℃, 6 h) to obtain 35 g of carbon-silicon mixed powder raw material.

[0023] (4) 60.92 g of the silicon-hafnium alloy powder raw material obtained in step (2) was weighed and placed at the bottom center of a graphite crucible; the porous C / C composite block obtained in step (1) was placed above the silicon-hafnium alloy powder, and the two were in contact; 6 g of the carbon-silicon mixed powder raw material obtained in step (3) was weighed and placed in the graphite crucible, and it was ensured that it did not contact the silicon-hafnium alloy powder raw material and the porous C / C composite (the mass ratio of the silicon-hafnium alloy powder, the porous C / C composite, and the carbon-silicon mixed powder was 2:1:0.2), thereby obtaining a graphite crucible containing the raw materials to be reacted.

[0024] (5) The graphite crucible described in step (4) was placed in a high-temperature furnace, vacuumed to below 10 Pa, and then heated to 1700℃ at a heating rate of 10℃ / min. After holding for 60 min, it was cooled to 1000℃ at a rate of 10℃ / min, and then the furnace body was naturally cooled to room temperature, thereby obtaining a HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating.

[0025] The XRD pattern of the composite material coating and substrate prepared in this example is shown in Figure 1 The main phases of the coating are SiC, HfC, and HfSi2, and the main phases of the substrate are C, HfC, SiC, and HfSi2, indicating that the HfC-SiC-HfSi2 coating-substrate integrated modified C / C composite material was successfully prepared. The scanning electron microscope image of the prepared composite material is shown in Figure 2 From the image, it can be seen that the thickness of the coating is about 100 μm, and it has a three-layer multiphase composite structure, i.e., the outer layer is uniformly covered with a layer of coarse SiC grains, the middle layer is composed of continuous HfSi2 and dispersedly distributed HfC grains, and in addition, there is a transition layer composed of fine SiC grains at the coating-carbon substrate interface, indicating that the HfC-SiC-HfSi2 modified C / C composite material with a SiC / HfSi2-HfC / SiC three-layer multiphase ceramic coating was successfully prepared. The composite material was subjected to ablation test at 2500℃ for 600 s under oxyacetylene flame, and the mass ablation rate and linear ablation rate were 0.673 mg / s and -0.853 μm / s, respectively, showing excellent ablation resistance.

[0026] Example 2 The difference from Example 1 is that in step (4), the mass ratio of the silicon-hafnium alloy powder, the porous C / C composite material, and the carbon-silicon mixed powder is 3:1:0.2, while the remaining steps are the same as in Example 1. The scanning electron microscope image of the composite material prepared in this example is shown below. Figure 3 As shown, the coating thickness significantly increased to approximately 160 μm. This indicates that the coating thickness can be controlled by altering the mass ratio of the silicon-hafnium alloy powder, the porous C / C composite material, and the carbon-silicon mixed powder. The composite material prepared in this example was subjected to ablation testing at 2500°C for 600 s under an oxyacetylene flame. The mass ablation rate and linear ablation rate were 0.345 mg / s and -1.071 μm / s, respectively, representing decreases of 48.74% and 25.56% compared to Example 1. This demonstrates that the increased coating thickness of the HfC-SiC-HfSi2 modified C / C composite material with a SiC / HfSi2-HfC / SiC three-layer multiphase ceramic coating contributes to improved ablation resistance.

[0027] Comparative Example 1 The difference from Example 1 is that in step (4), the mass ratio of silicon-hafnium alloy powder, porous C / C composite material, and carbon-silicon mixed powder is 3:1:0.5, while the remaining steps are the same as in Example 1. The scanning electron microscope image of the composite material prepared in this comparative example is shown below. Figure 4 As shown in the figure, the coating of the composite material consists of a single SiC layer. This indicates that excessive carbon-silicon mixed powder in the experimental environment affects the melt penetration of the hafnium-silicon alloy, thus preventing the formation of a three-layer multiphase coating on the surface of the composite material.

[0028] Comparative Example 2 The difference from Example 1 is that step (3) was not performed, and the carbon-silicon mixed powder was not placed in step (4). The remaining steps are consistent with Example 1. This comparative example is to verify whether the carbon-silicon mixed powder is a key factor in the generation of the outer SiC layer in the three-layer multiphase coating of the present invention. The scanning electron microscope image of the composite material prepared in this example is shown below. Figure 5 As shown in the figure, the coating of the composite material lacks an outer SiC layer. That is, when the experimental environment lacks carbon and silicon sources, it is impossible to form the outer SiC layer in the multilayer coating.

[0029] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. HfC-SiC-HfSi2 modified C / C composite with a three-layer multiphase ceramic coating, characterized in that, The composite material comprises a coating and a substrate; The coating is a three-layer multiphase composite structure, which is composed of an outer layer of SiC, an intermediate layer of HfC-HfSi2, and an inner layer of SiC; The thickness of the coating is 100-160 μm; The substrate is composed of C / C and HfC-SiC-HfSi2 ceramic components; The composite material is tightly combined by the coating and the substrate through chemical reaction, forming a coating-substrate integrated structure; The HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating is prepared by a one-step reaction infiltration method.

2. The one-step reactive infiltration processing production method of claim 1, wherein, The method comprises the following steps: Step (1): cutting a porous C / C composite material into a regular block of appropriate size, polishing and ultrasonic cleaning, and then drying, weighing and recording; Step (2): according to the mass of the porous C / C composite material in step (1), a certain mass ratio of hafnium silicon alloy powder is weighed and placed in a graphite crucible, and the porous C / C composite material is placed above the hafnium silicon alloy powder; Step (3): according to the mass of the porous C / C composite material in step (1), a certain mass ratio of carbon-silicon mixed powder is weighed and placed in the graphite crucible in step (2), and it is ensured that it is uniformly distributed around the hafnium silicon alloy powder without contacting each other; Step (4): place the graphite crucible in step (3) in a high-temperature device, vacuumize, heat the furnace body, keep the temperature for a period of time after reaching the required temperature, then wait for the furnace body to drop to room temperature, and obtain a HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating.

3. The one-step reactive infiltration and permeation manufacturing method of claim 2, wherein, The porous C / C composite material in step (1) is a 3D continuous carbon fiber reinforced carbon-based composite material, with a density of 1.2-1.4 g / cm 3 and a porosity of 15-30%.

4. The one-step reactive infiltration and permeation manufacturing method of claim 2, wherein, The Hf / Si molar ratio of the hafnium silicon alloy powder in step (2) is 1:2; the carbon-silicon mixed powder in step (3) is a mixture of Si powder and C powder, and the molar ratio of Si powder to C powder is 1:

1.

5. The one-step reactive infiltration and permeation manufacturing method of claim 2, wherein, The particle size of the hafnium silicon alloy powder in step (2) is 800-1200 nm.

6. The one-step reactive infiltration and phitration fabrication method of claim 2, wherein, The mass ratio of the hafnium silicon alloy powder to the porous C / C composite material in step (2) is (2-3):

1.

7. The one-step reactive infiltration and permeation manufacturing method of claim 2, wherein, The hafnium silicon alloy powder in step (2) is placed below the porous C / C composite material, i.e. they are in direct contact.

8. The one-step reactive melt preparation method of claim 2, wherein, The mass ratio of the carbon-silicon mixed powder to the porous C / C composite material in step (3) is (0.2-0.5):1; The carbon-silicon mixed powder in step (3) is uniformly distributed around without contacting the porous C / C composite material and the hafnium silicon alloy powder.

9. The one-step reactive melt preparation method of claim 2, wherein, The vacuum condition in step (4) is to vacuumize the high-temperature device to below 10 Pa; The temperature rising rate in step (4) is 5-10 ℃ / min, and the holding time is 30-60 min; The temperature falling rate in step (4) is 5-10 ℃ / min.

10. Application of the HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating in claim 1 and / or the HfC-SiC-HfSi2 modified C / C composite material with a three-layer multiphase ceramic coating prepared by the preparation method in any one of claims 2-9 in a high-temperature aerobic environment.

Images