A carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface and a preparation method thereof

Abstract

The present invention discloses a carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface and a preparation method thereof. The carbon-based composite material comprises a matrix and a coating. The method includes preparing a SiC transition layer on the surface of the carbon-based composite material by the method of pack infiltration, and then preparing a (Hf-Zr-Ta)C solid solution ceramic coating on the SiC transition layer by SAPS. The present invention uses SAPS to prepare a (Hf-Zr-Ta)C solid solution ceramic coating on the surface of the carbon-based composite material coated with the SiC transition layer; (Hf-Zr-Ta)C forms a composite oxide composed of high melting point (Hf,Zr)O2 and low oxygen diffusion coefficient (Hf,Zr)6Ta2O 17 in the ablation environment, which can not only resist the erosion of high-speed air flow, but also hinder the diffusion of oxygen into the interior of the coating; in addition, during the cooling process, the peritectic transformation of the molten oxide mainly composed of (Hf,Zr)O2 and Ta to (Hf,Zr)6Ta2O 17 counteracts the volume expansion caused by the phase transformation of t-(Hf,Zr)O2 to m-(Hf,Zr)O2, reducing the initiation and propagation of cracks in the coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultra-high temperature ablation-resistant functional coatings, and relates to a carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface and a preparation method thereof. Background Art

[0002] Carbon-based composite materials have the advantages of low density, low coefficient of thermal expansion, high specific strength, and excellent mechanical properties in a high-temperature inert atmosphere, and are considered to be one of the most promising ultra-high temperature structural materials, with wide applications in the fields of aviation, aerospace, and some civilian areas; however, carbon-based composite materials are prone to erosion in an oxygen ablation environment above 2000 °C, resulting in a significant decline in their mechanical properties; currently, preparing an ablation-resistant coating on the surface of carbon-based composite materials is the most effective method to solve this problem. Ultra-high temperature ceramics (UHTCs) have high specific strength, high melting points, and good ablation resistance. Among them, carbide ultra-high temperature ceramics (HfC: 3890 °C, ZrC: 3540 °C, TaC: 3950 °C) have higher melting points and are considered to be one of the best candidate materials for ablation-resistant coatings of carbon-based composite materials.

[0003] Document 1 "Wang Y, Xiong X, Li G, et al. Ablation behavior of HfC protective coatings for carbon / carbon composites in an oxyacetylene combustion flame [J]. Corrosion science, 2012, 65: 549-555." prepared an HfC coating on the carbon-based surface by chemical vapor deposition. The HfO2 layer protective layer formed during the ablation process improved the ablation resistance of the material. However, the porous HfO2 could not provide long-term (more than 60 s) ablation protection for the carbon-based composite material.

[0004] The composite glass oxide layer composed of HfO2 and SiO2 reported in Document 2 "Ren J, Zhang Y, Fu Y, et al. Effects of the second phase on the microstructure and ablation resistance of HfC coating on C / C composites[J]. Surface and Coatings Technology, 2018, 344: 250-258." has better protection. However, because the viscosity of SiO2 decreases with increasing temperature, the oxide layer is prone to spalling in a long-term ablation environment (exceeding 120 s). Therefore, there are still limitations when using single-phase carbides or modified carbides as ablation-resistant coating materials.

[0005] In recent years, multi-component solid solution ceramics have attracted great attention due to their unique entropy effect. Research shows that multi-component ceramics not only have extremely high melting points and more excellent mechanical properties, but also have great potential in the field of oxidation / ablation resistance. The patent document (China Authorization No. CN114853506B) discloses a (Hf 1 / 3 Zr 1 / 3 Ti 1 / 3 )C medium-entropy ceramic coating on the surface of a carbon-based composite material and its preparation method. Research shows that the ablation resistance of the (Hf 1 / 3 Zr 1 / 3 Ti 1 / 3 )C medium-entropy ceramic coating is better than that of the HfC-ZrC-TiC multi-phase coating.

[0006] At present, it is found that the configurational entropy of equimolar carbide solid solution ceramics is the largest, but the ablation resistance of the material is not necessarily the best. Therefore, in this patent application, SAPS is used to prepare (Hf-Zr-Ta)C solid solution ceramic coatings with different Ta contents on the carbon-based surface to explore the influence law of Ta content on the ablation resistance of (Hf-Zr-Ta)C solid solution ceramic coatings, so as to obtain the proportion of coating composition elements with excellent ablation resistance. Summary of the Invention

[0007] In order to avoid the deficiencies of the prior art, the present invention proposes a long-life ultra-high-temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on the surface of a carbon-based composite material and its preparation method. First, a SiC transition layer is prepared on the surface of the carbon-based composite material by the pack cementation method, and then a (Hf-Zr-Ta)C solid solution ceramic coating is prepared on the SiC transition layer by SAPS. The purpose of the invention is to provide long-term ablation protection for the carbon-based composite material in an ultra-high-temperature aerobic environment above 2100 °C;

[0008] For this, the specific solution adopted by the present invention is as follows:

[0009] The present invention discloses a carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface. The carbon-based composite material includes a matrix and a coating. The coating includes a transition layer and an outer coating. The transition layer covers the matrix, and the outer coating covers the transition layer. The composition of the outer coating includes (Hf-Zr-Ta)C.

[0010] The present invention also discloses a preparation method of a carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface, which is characterized by including the following steps:

[0011] Step 1: Mix Si powder, C powder, and Al2O3 powder evenly after ball milling.

[0012] Step 2: Put the mixed powder obtained in Step 1 into a graphite crucible, then bury the carbon-based composite material in it, and then put the graphite crucible into a high-temperature heat treatment furnace. Under the protection of an inert gas, heat it to a set temperature and keep it warm for a period of time, and then cool it to room temperature with the furnace and take samples to obtain a carbon-based composite material coated with a SiC transition layer.

[0013] Step 3: Mix HfO2 powder, ZrO2 powder, Ta2O5 powder, and C powder evenly after ball milling.

[0014] Step 4: Put the mixed powder obtained in Step 3 into a high-temperature heat treatment furnace, after introducing an inert gas, heat it to a set temperature and keep it warm for a period of time, and then cool it to room temperature with the furnace and take samples to obtain (Hf-Zr-Ta)C solid solution ceramic powder.

[0015] Step 5: After ball milling and sieving the powder obtained in Step 4, carry out spheroidizing granulation by spray drying method.

[0016] Step 6: Spray the (Hf-Zr-Ta)C solid solution ceramic powder granulated in Step 5 on the carbon-based composite material coated with a SiC transition layer obtained in Step 2 to obtain an anti-ablation (Hf-Zr-Ta)C solid solution ceramic coating.

[0017] The advantages of the present invention compared with the prior art are as follows: The present invention uses SAPS to prepare a (Hf-Zr-Ta)C solid solution ceramic coating on the surface of a carbon-based composite material coated with a SiC transition layer; (Hf-Zr-Ta)C forms a composite oxide composed of high melting point (Hf,Zr)O2 and low oxygen diffusion coefficient (Hf,Zr)6Ta2O in an ablation environment. At the same time, during the ablation process, (Hf,Zr)6Ta2O 17 composed of 17It is transformed into molten oxides mainly composed of t-(Hf,Zr)O2 and Ta. The high melting point (Hf,Zr)O2 can effectively resist the erosion of high-speed airflows. The molten oxides promote the densification of the oxide layer and can hinder the diffusion of oxygen into the coating interior. During the cooling process, the molten oxides mainly composed of t-(Hf,Zr)O2 and Ta are transformed into (Hf,Zr)6Ta2O 17 , and the volume shrinkage caused by the peritectic transformation offsets the volume expansion caused by the phase transformation from t-(Hf,Zr)O2 to m-(Hf,Zr)O2, reducing the initiation and propagation of cracks in the coating. Therefore, the dense and stable oxide layer formed after the ablation of (Hf-Zr-Ta)C can effectively protect the C / C composite material.

[0018] In addition, compared with TiC (melting point: 3140 °C, thermal conductivity: 22.2 W / (m·K), coefficient of thermal expansion: 7.0×10 -6 / °C), TaC (melting point: 3950 °C, thermal conductivity: 33.5 W / (m·K), coefficient of thermal expansion 6.3×10 -6 / °C) has better comprehensive properties; firstly, TaC has a higher melting point and better temperature resistance; secondly, TaC has a higher thermal conductivity and can quickly dissipate the heat on the coating surface to other places during ablation, thereby reducing the temperature at the ablation center of the coating and improving the ablation resistance of the material; finally, TaC has a lower coefficient of thermal expansion and is closer to the carbon-based composite material. During the coating preparation and oxidation / ablation process, the thermal stress in the coating is smaller and the tendency of the coating to crack is smaller. Compared with TiO2 (1840 °C), Ta2O5 (1872 °C) has a higher melting point and can more effectively resist the erosion of airflows; in addition, compared with the +4 valence of Ti, the +5 valence of Ta cations is higher, and the number of vacancies in the corresponding oxide is less. The reduction in the number of vacancies makes the oxide more stable. Therefore, the (Hf-Zr-Ta)C coating is more likely to remain stable during ablation. Through experiments, it is found that compared with the (Hf 1 / 3 Zr 1 / 3 Ti 1 / 3 )C coating, after 60 s of ablation, the linear ablation rate of the (Hf 1 / 3 Zr 1 / 3Ta 1 / 3 )C coating is reduced by 28%. Therefore, preparing a (Hf-Zr-Ta)C ceramic coating on the surface of a carbon-based composite material can further improve the ablation resistance of the carbon-based composite material coating.

[0019] Preparing a (Hf 0.425 Zr 0.425 Ta 0.425 )C anti-ablation coating can provide at least 300 s of effective protection for carbon-based composite materials in a super-high temperature environment above 2100 °C. Description of the Drawings

[0020] Figure 1 Macrophotographs after ablation for each example and comparative example in the present invention.

[0021] Figure 2 X-ray diffraction patterns of (Hf-Zr-Ta)C solid solution ceramic powders with different ratios obtained through Step 3 and Step 4 in the present invention.

[0022] Figure 3 For (Hf 0.425 Zr 0.425 Ta 0.15 )C coating prepared in Example 5 of the present invention, macroscopic pictures before and after ablation;

[0023] Among them, Figure 3 (a) is before ablation, Figure 3 (b) is after ablation for 120 s, Figure 3 (c) is after ablation for 300 s.

[0024] Figure 4 For (Hf 0.425 Zr 0.425 Ta 0.15 )C coating prepared in Example 5 of the present invention, X-ray diffraction pattern after ablation.

[0025] Figure 5 For (Hf 0.425 Zr 0.425 Ta 0.15 )C coating prepared in Example 5 of the present invention, surface SEM and cross-section BSE pictures before and after ablation;

[0026] Among them Figure 5 (a) and Figure 5 (b) are scanning electron microscope pictures of (Hf0.425Zr0.425Ta0.15)C coating before ablation, Figure 5 (c) and Figure 5 (d) are scanning electron microscope pictures after ablation for 120 s.

[0027] Figure 6 For (Hf 0.5 Zr 0.5 )C ablation before and after prepared in Comparative Example 1 of the present invention, macroscopic pictures;

[0028] Among them Figure 6 (a) is before ablation, Figure 6 (b) is after ablation for 120 s.

[0029] Figure 7 For (Hf 0.5 Zr 0.5 )C cross-section BSE pictures before and after ablation prepared in Comparative Example 1 of the present invention.

[0030] wherein Figure 7 (a) is before ablation, Figure 7 (b) is after ablation for 120 s. Detailed implementation manners

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention.

[0032] Embodiment 1

[0033] A carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface, the carbon-based composite material includes a matrix and a coating, the coating includes a transition layer and an outer coating, the transition layer covers the matrix, the outer coating covers the transition layer, and the composition of the outer coating includes (Hf-Zr-Ta)C; the transition layer is SiC; the composition of the outer coating includes (Hf 0.425 Zr 0.425 Ta 0.15 )C.

[0034] A preparation method of a carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface, comprising the following steps:

[0035] Step 1: Weigh Si powder, C powder, and Al2O3 powder with a mass ratio of 9:2:1 and place them in a ball mill tank, and mix them on a ball mill for 6 h to obtain a mixed powder;

[0036] Step 2: Bury the carbon-based composite material in a graphite crucible filled with the mixed powder obtained in Step 1, place the graphite crucible in a high-temperature heat treatment furnace, under the protection of an inert gas, the high-temperature heat treatment furnace is heated from room temperature to 2000 °C at a heating rate of 10 °C / min and kept warm for 2 h, and then cooled to room temperature with the furnace to take samples, and a carbon-based composite material coated with a SiC transition layer is obtained;

[0037] Step 3: Weigh HfO2 powder, ZrO2 powder, Ta2O5, and C powder with a molar ratio of 2:2:1:19 and place them in a ball mill tank, and mix them on a planetary ball mill for 4 h to obtain a mixed powder;

[0038] Step 4: Load the mixed powder obtained in Step 3 into a graphite crucible, place the graphite crucible in a high-temperature heat treatment furnace, evacuate and then introduce argon, the high-temperature heat treatment furnace is heated from room temperature to 2100 °C at a heating rate of 5 °C / min and kept warm for 2 h, and then cooled to room temperature with the furnace to take samples, as Figure 2 shown, to obtain (Hf 1 / 3 Zr1 / 3 Ta 1 / 3 )C solid solution ceramic powder;

[0039] Step 5: After ball milling and sieving the powder obtained in Step 4, spheroidizing granulation is carried out by spray drying method;

[0040] Step 6: Spray the granulated (Hf 1 / 3 Zr 1 / 3 Ta 1 / 3 )C solid solution ceramic powder on the carbon-based composite material coated with a SiC transition layer obtained in Step 2 to obtain an ablative-resistant (Hf 1 / 3 Zr 1 / 3 Ta 1 / 3 )C solid solution ceramic coating.

[0041] The spraying parameters are: spraying power: 45 kW; main gas flow rate (Ar): 70 L / min; number of spraying times: 10 times.

[0042] From Figure 2 the X-ray diffraction pattern of the powder obtained through Steps 3 and 4, it can be seen that there are no oxides and intermediate carbides in the figure, indicating that the (Hf 1 / 3 Zr 1 / 3 Ta 1 / 3 )C solid solution ceramic powder is successfully prepared.

[0043] Example 2

[0044] Referring to the steps of Example 1, only change the molar ratio of HfO2 powder, ZrO2 powder, Ta2O5 and C powder in Step 3. In this example, HfO2 powder, ZrO2 powder, Ta2O5 and C powder with a molar ratio of 19:19:1:121 are weighed and mixed. After high-temperature heat treatment and spheroidizing granulation, (Hf 0.475 Zr 0.475 Ta 0.05 )C solid solution ceramic coating is prepared on the carbon-based composite material coated with a SiC coating by SAPS.

[0045] From Figure 2 it can be seen that single-phase (Hf 0.475 Zr 0.475 Ta 0.05 )C solid solution ceramic powder is successfully prepared.

[0046] Example 3

[0047] Referring to the steps of Example 1, only change the molar ratios of HfO2 powder, ZrO2 powder, Ta2O5 and C powder in step 3. In this example, HfO2 powder, ZrO2 powder, Ta2O5 and C powder with a molar ratio of 9:9:1:61 are weighed and mixed. After high-temperature heat treatment and spheroidizing granulation, (Hf 0.45 Zr 0.45 Ta 0.1 )C solid solution ceramic coatings are prepared on the carbon-based composite material coated with SiC coating by SAPS.

[0048] It can be seen from Figure 2 that single-phase (Hf 0.45 Zr 0.45 Ta 0.1 )C solid solution ceramic powders are successfully prepared.

[0049] Example 4

[0050] Referring to the steps of Example 1, only change the molar ratios of HfO2 powder, ZrO2 powder, Ta2O5 and C powder in step 3. In this example, HfO2 powder, ZrO2 powder, Ta2O5 and C powder with a molar ratio of 4:4:1:31 are weighed and mixed. After high-temperature heat treatment and spheroidizing granulation, (Hf 0.4 Zr 0.4 Ta 0.2 )C coatings are prepared on the carbon-based composite material coated with SiC coating by SAPS.

[0051] It can be seen from Figure 2 that single-phase (Hf 0.4 Zr 0.4 Ta 0.2 )C solid solution ceramic powders are successfully prepared.

[0052] Example 5

[0053] Referring to the steps of Example 1, only change the molar ratios of HfO2 powder, ZrO2 powder, Ta2O5 and C powder in step 3. In this example, HfO2 powder, ZrO2 powder, Ta2O5 and C powder with a molar ratio of 17:17:3:123 are weighed and mixed. After high-temperature heat treatment and spheroidizing granulation, (Hf 0.425 Zr 0.425 Ta 0.15 )C solid solution ceramic coatings are prepared on the carbon-based composite material coated with SiC coating by SAPS.

[0054] It can be seen from Figure 2 that single-phase (Hf 0.425 Zr 0.425 Ta 0.15 )C solid solution ceramic powders are successfully prepared; it can be seen from Figure 3 that after ablation, (Hf0.425 Zr 0.425 Ta 0.15 ) The C coating maintains a complete morphology and has a good bonding with the substrate, and the coating structure remains intact; from Figure 4 it can be seen that the oxide layer after ablation is mainly composed of (Hf,Zr)O2 and (Hf,Zr)6Ta2O 17 ; from Figure 5 it can be seen that a dense oxide layer is formed after the ablation of the coating, which can provide effective ablation protection for the C / C substrate and shows excellent ablation resistance performance.

[0055] Comparative Example 1

[0056] Referring to the steps of Example 1, only change the composition and molar ratio of HfO2 powder, ZrO2 powder, Ta2O5 and C powder in Step 3; in this comparative example, HfO2 powder, ZrO2 powder and C powder with a molar ratio of 1:1:6 are weighed and mixed. After high-temperature heat treatment and spheroidization granulation, (Hf 0.5 Zr 0.5 )C solid solution ceramic coating is prepared on the carbon-based composite material coated with SiC coating by SAPS.

[0057] From Figure 2 it can be seen that single-phase (Hf 0.5 Zr 0.5 )C solid solution ceramic powder is successfully prepared; from Figure 6 it can be seen that obvious peeling appears at the edge of the coating after ablation; from Figure 7 it can be seen that obvious delamination appears in the coating after ablation, and the ablation resistance performance of the coating is poor.

[0058] Combining with the attached Figure 1 , the material composition of Example 1 is (Hf 1 / 3 Zr 1 / 3 Ta 1 / 3 )C, the ablation time (s) is 60, and the linear ablation rate (μm / s) is 1.20. The macroscopic photograph after its ablation is as shown in Figure 1 (a), and its coating is dense and intact;

[0059] The material composition of Example 2 is (Hf 0.475 Zr 0.475 Ta 0.15 )C, the ablation time (s) is 120, and the linear ablation rate (μm / s) is 0.83. The macroscopic photograph after its ablation is as shown in Figure 1 (b), and its coating has no obvious defects;

[0060] The material composition of Example 3 is (Hf 0.45 Zr 0.45 Ta 0.1)C, the ablation time (s) is 120, the linear ablation rate (μm / s) is 0.74, and the macroscopic photograph after ablation is as Figure 1 (c) shows that there are no obvious defects in its coating;

[0061] The material composition of Example 4 is (Hf 0.4 Zr 0.4 Ta 0.2 )C, the ablation time (s) is 120, the linear ablation rate (μm / s) is 0.71, and the macroscopic photograph after ablation is as Figure 1 (d) shows that there are no obvious defects in its coating;

[0062] The material composition of Example 5 is (Hf 0.425 Zr 0.425 Ta 0.15 )C, the ablation time (s) is 120, the linear ablation rate (μm / s) is 0.57, and the macroscopic photograph after ablation is as Figure 1 (e) shows that its coating is dense and complete;

[0063] The material composition of Comparative Example 1 is (Hf 0.5 Zr 0.5 )C, the ablation time (s) is 120, the linear ablation rate (μm / s) is 0.86, and the macroscopic photograph after ablation is as Figure 1 (f) shows that peeling occurs at the edge of its coating;

[0064] The material composition of Comparative Example 2 is (Hf 1 / 3 Zr 1 / 3 Ti 1 / 3 )C, the ablation time (s) is 60, the linear ablation rate (μm / s) is 1.67, and the macroscopic photograph after ablation is as Figure 1 (g) shows that its coating expands severely in volume, referring to Patent CN114853506B.

[0065] The above describes the present invention and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar structural manners and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A carbon-based composite material with a long-life ultra-high temperature micro-ablation (Hf-Zr-Ta)C solid solution ceramic coating on its surface, characterized in that, The carbon-based composite material comprises a matrix and a coating. The coating includes a transition layer and an outer coating. The transition layer covers the matrix, and the outer coating covers the transition layer. The composition of the outer coating includes (Hf-Zr-Ta)C; The preparation method of the carbon-based composite material comprises the following steps: Step 1: Mix Si powder, C powder, and Al2O3 powder evenly after ball milling; Step 2: Put the mixed powder obtained in Step 1 into a graphite crucible, then bury the carbon-based composite material therein, and then put the graphite crucible into a high-temperature heat treatment furnace. Under the protection of an inert gas, heat it up to the set temperature and hold for a period of time, and then cool it to room temperature with the furnace for sampling to obtain a carbon-based composite material coated with a SiC transition layer; Step 3: Mix HfO2 powder, ZrO2 powder, Ta2O5 powder, and C powder evenly after ball milling; Step 4: Place the mixed powder obtained in Step 3 in a high-temperature heat treatment furnace. After introducing an inert gas, heat it up to the set temperature and hold for a period of time, and then cool it to room temperature with the furnace for sampling to obtain (Hf-Zr-Ta)C solid solution ceramic powder; Step 5: After ball milling and sieving the powder obtained in Step 4, carry out spheroidizing granulation by spray drying; Step 6: Spray the (Hf-Zr-Ta)C solid solution ceramic powder granulated in Step 5 on the carbon-based composite material coated with a SiC transition layer obtained in Step 2 to obtain an anti-ablation (Hf-Zr-Ta)C solid solution ceramic coating.

2. The carbon-based composite material according to claim 1, wherein The composition of the outer coating includes (Hf 0.425 Zr 0.425 Ta 0.15 )C.

3. The carbon-based composite material according to claim 1, wherein In Step 1, the mass ratio of Si:C:Al2O3 is (8~14):(1~4):(0.5~1.5).

4. The carbon-based composite material according to claim 1, wherein, In Step 2, the heat treatment temperature is 1800~2300 °C, the holding time is 1~3 h, and the heating rate is 5~10 °C / min.

5. The carbon-based composite material according to claim 1, characterized in that, In Step 3, the molar ratio of HfO2:ZrO2:Ta2O5:C is (1~19):(1~19):(0.5~1):(19~121).

6. The carbon-based composite material according to claim 1, characterized in that, In Step 4, the heat treatment temperature is 1900~2300 °C, the holding time is 1~3 h, and the heating rate is 5~10 °C / min.

7. The carbon-based composite material according to claim 1, characterized in that, In Step 6, the spraying parameters are: spraying power: 35~55 kW; using Ar as the main gas, the main gas flow rate is: 60~80 L / min; the number of spraying times: 8~12 times.

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