A method for preparing an aluminum-modified high-entropy silicide coating

Abstract

This invention relates to the field of antioxidant coating technology, and more particularly to a method for preparing an aluminum-modified high-entropy silicide coating. The method for preparing the aluminum-modified high-entropy silicide coating provided by this invention includes the following steps: melting to prepare an aluminum-modified high-entropy alloy; the composition of the aluminum-modified high-entropy alloy is (NbMoTaW). 1‑x Al x Where 0 < x ≤ 0.2, and Nb, Mo, Ta, and W are in equiatomic ratios; the aluminum-modified high-entropy alloy is embedded and infiltrated with Si to obtain the aluminum-modified high-entropy silicide coating; the embedding and infiltrating temperature is 1000~1300℃. This invention, by adding Al to the NbMoTaW alloy, can effectively improve the cracking problem of NbMoTaW alloy during embedding and infiltrating at higher temperatures, obtaining a dense and continuous high-entropy alloy silicide coating, improving coating deposition efficiency, and simultaneously forming a high-entropy alloy silicide coating with good oxidation resistance and diffusion inhibition functions.

Description

Technical Field

[0001] This invention relates to the field of antioxidant coating technology, and more particularly to a method for preparing an aluminum-modified high-entropy silicide coating. Background Technology

[0002] With the development of cutting-edge fields such as aerospace, propulsion systems, and nuclear energy, traditional nickel-based superalloys can no longer meet the requirements when the operating temperature exceeds 1150℃. Niobium-based alloys, with their advantages of high specific strength, good toughness, and machinability, are a better choice for high-temperature structural materials. However, niobium-based alloys have extremely poor oxidation resistance, and begin to oxidize severely in air above about 400℃. Above 600℃, the oxidation rate accelerates dramatically, forming loose and porous Nb2O5 oxides, leading to catastrophic "pest" oxidation (i.e., powdering oxidation). Oxygen rapidly invades along the grain boundaries. Therefore, the use of niobium-based alloys at high temperatures requires a high-performance anti-oxidation coating system.

[0003] Silicide coatings exhibit good thermal stability and can be used at high temperatures. At high temperatures, silicides react with oxygen to form a dense layer of SiO2 on the coating surface, effectively hindering oxygen diffusion. Simultaneously, SiO2 possesses a certain degree of fluidity at high temperatures, allowing it to promptly fill microcracks and pores in the coating, resulting in excellent high-temperature self-healing properties. Among silicide coatings, MoSi2 exhibits a stable structure and a high melting point. After high-temperature oxidation, the SiO2 glass layer formed on the surface is relatively dense, and its coefficient of thermal expansion is very close to that of niobium alloys. Therefore, MoSi2 is currently the most widely used silicide coating.

[0004] However, at high temperatures, Si diffuses both inward and outward in MoSi2, causing MoSi2 at the interface to transform into Mo5Si3, which has poor oxidation resistance. This leads to decreased interfacial adhesion and a shortened coating life, necessitating the addition of a diffusion barrier layer (currently mostly WSi2) to prevent silicon diffusion into the substrate. In high-entropy silicide coatings, the significant configurational entropy resulting from the high-entropy effect can significantly improve the stability of the silicide phase. Disilicides are less prone to transforming into lower-valence silicide phases, exhibiting stronger resistance to "silicide degradation." Adjusting the proportions of different metals in the coating can also more precisely control the coefficient of thermal expansion, making it more suitable for niobium-based alloys and reducing the impact of thermal stress during thermal cycling.

[0005] Currently, the preparation of (NbMoTaW)Si2 coatings is mainly based on the optimization of the embedding silicon infiltration process. However, when the embedding temperature is high, the internal stress of the coating growth increases, and the lattice distortion effect accelerates the diffusion of Si inward along the grain boundaries, leading to cracking of the coating and the substrate. On the other hand, reducing the embedding temperature will result in excessively low deposition efficiency. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for preparing an aluminum-modified high-entropy silicide coating. The present invention can avoid cracking of the high-entropy silicide coating and the substrate when the embedding temperature is high, thereby improving the embedding deposition efficiency.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an aluminum-modified high-entropy silicide coating, comprising the following steps: melting to prepare an aluminum-modified high-entropy alloy; the composition of the aluminum-modified high-entropy alloy is (NbMoTaW). 1-x Al x Where 0 < x ≤ 0.2, and Nb, Mo, Ta, and W are in equal atomic ratios; The aluminum-modified high-entropy alloy is embedded and infiltrated with Si to obtain the aluminum-modified high-entropy silicide coating; the embedding and infiltrating temperature is 1000~1300℃.

[0008] Preferably, by mass percentage, the infiltrating agent used for embedding Si comprises 20-40% silicon powder, 2-5% activator, 0-1% B powder, and the balance Al2O3.

[0009] Preferably, the activator includes NaF or NH4F.

[0010] Preferably, the infiltrator comprises 34% silica powder, 2.5% NaF, 1% B powder, and the balance Al2O3.

[0011] Preferably, the heat preservation time for the Si embedding and infiltration is 3 to 20 hours.

[0012] Preferably, the rate of heating to the temperature of the embedded Si is ≤5℃ / min.

[0013] Preferably, the melting is vacuum arc melting.

[0014] Preferably, the temperature for embedding and infiltrating Si is 1200°C.

[0015] Preferably, 0.05 ≤ x ≤ 0.2.

[0016] The present invention provides an aluminum-modified high-entropy silicide coating prepared by the preparation method described above.

[0017] This invention provides a method for preparing an aluminum-modified high-entropy silicide coating, comprising the following steps: melting to prepare an aluminum-modified high-entropy alloy; the composition of the aluminum-modified high-entropy alloy is (NbMoTaW). 1-x Al xWhere 0 < x ≤ 0.2, and Nb, Mo, Ta, and W are in equiatomic ratios; the aluminum-modified high-entropy alloy is embedded with Si to obtain the aluminum-modified high-entropy silicide coating; the embedding temperature of Si is 1000~1300℃. This invention, by adding aluminum to the NbMoTaW high-entropy alloy, can reduce the inward diffusion rate of Si along grain boundaries during high-temperature embedding, avoid cracking of the coating and substrate, improve embedding deposition efficiency, and simultaneously improve alloy toughness, reducing coating detachment caused by thermal stress during thermal cycling. Attached Figure Description

[0018] Figure 1 This is a cross-sectional morphology diagram of the embedded coating after penetration in Example 1; Figure 2 This is a cross-sectional morphology diagram of the embedded coating after penetration in Example 3; Figure 3 This is a cross-sectional morphology diagram of the embedded coating after penetration in Example 4; Figure 4 This is a cross-sectional morphology diagram of the embedded coating in Comparative Example 1. Figure 5 This is a cross-sectional morphology diagram of the coating after infiltration in Comparative Example 2. Detailed Implementation

[0019] This invention provides a method for preparing an aluminum-modified high-entropy silicide coating, comprising the following steps: melting to prepare an aluminum-modified high-entropy alloy; the composition of the aluminum-modified high-entropy alloy is (NbMoTaW). 1-x Al x Where 0 < x ≤ 0.2, and Nb, Mo, Ta, and W are in equal atomic ratios; The aluminum-modified high-entropy alloy is embedded and infiltrated with Si to obtain the aluminum-modified high-entropy silicide coating; the embedding and infiltrating temperature is 1000~1300℃.

[0020] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0021] This invention first prepares an aluminum-modified high-entropy alloy by melting and smelting.

[0022] In this invention, the composition of the aluminum-modified high-entropy alloy is (NbMoTaW). 1-x Al x Where 0 < x ≤ 0.2, Nb, Mo, Ta and W are in equal atomic ratios; x refers to the atomic doping of Al, for example, when x = 0.2, it means that the atomic doping of Al is 20 at%; in specific embodiments, the atomic doping of Al can be 5%, 8%, 10%, 12%, 15%, 18% or 20%.

[0023] In this invention, the melting process is preferably vacuum arc melting. This invention does not impose any special limitations on the vacuum arc melting process; any process well-known in the art that ensures uniform melting is acceptable. In the embodiments of this invention, the purity of each metal raw material used is above 99.9%; the melting process preferably involves at least five remelting cycles to ensure uniform composition.

[0024] After obtaining the aluminum-modified high-entropy alloy, the present invention embeds and infiltrates the aluminum-modified high-entropy alloy with Si to obtain the aluminum-modified high-entropy silicide coating.

[0025] Before the Si embedding process, the aluminum-modified high-entropy alloy is preferably surface-treated. In this invention, the surface treatment preferably includes: grinding, washing, and drying sequentially. The grinding process is not specifically limited; grinding until the alloy surface is smooth is sufficient. In embodiments of this invention, specifically, 320-grit, 500-grit, 800-grit, and 1000-grit SiC wet sandpaper are used sequentially for grinding. In this invention, the washing process is preferably performed using ultrasonic cleaning with deionized water and anhydrous ethanol sequentially. In this invention, the drying temperature is preferably 100°C, and the drying time is preferably 1 hour.

[0026] In this invention, the infiltrating agent used for embedding Si preferably comprises 20-40% silicon powder, 2-5% activator, 0-1% boron powder, and the balance Al2O3, by mass percentage. Specifically, the silicon powder content in the infiltrating agent can be 20%, 24%, 28%, 30%, 34%, 38%, or 40%; the activator content can be 2%, 2.5%, 3%, 4%, or 5%; and the boron powder content can be 0%, 0.2%, 0.4%, 0.6%, 0.8%, or 1%. Preferably, the activator comprises NaF or NH4F, more preferably NaF.

[0027] In this invention, the preparation method of the infiltrator preferably includes the following steps: first, vacuum drying of silicon powder, B powder, and Al2O3 powder; then, weighing silicon powder, activator, B powder, and Al2O3 according to the mass ratio and ball milling to obtain the infiltrator. In this invention, the ball milling speed is preferably 100 r / min, and the ball milling time is preferably 2 h. This invention uses ball milling to ensure uniform mixing of the components. In this invention, the vacuum drying temperature is preferably 100℃, and the vacuum drying time is preferably 10 h.

[0028] The present invention does not have special requirements for the specific operation of the Si embedding and infiltration process; any operation well known in the art can be used. Specifically, the aluminum-modified high-entropy alloy and the infiltration agent are loaded into a crucible and compacted to ensure that the aluminum-modified high-entropy alloy is completely surrounded by the infiltration agent. The crucible is then sealed and placed in a sintering furnace for Si embedding and infiltration. Preferably, the present invention uses sealing putty to seal the crucible, and then leaves it in the air for more than 8 hours to allow the sealing putty to cure.

[0029] In this invention, the Si embedding and infiltration is preferably carried out under argon protection. The Si embedding and infiltration temperature is preferably 1000~1300℃, and in specific embodiments it can be 1000, 1100, 1200 or 1300℃; the heating rate to the Si embedding and infiltration temperature is preferably ≤5℃ / min. The Si embedding and infiltration holding time is preferably 3~20h, and in specific embodiments it can be 3, 5, 8, 10, 12, 15, 18 or 20h.

[0030] After the heat preservation is completed, the present invention preferably cools down the furnace, and the cooling rate is preferably no more than 2°C / min. After cooling down to below 100°C, the argon gas is turned off, the product is taken out and ultrasonically cleaned with anhydrous ethanol to obtain the target product.

[0031] This invention improves the cracking problem of NbMoTaW alloy during embedding at high temperatures by adding Al, resulting in a dense and continuous high-entropy alloy silicide coating, which improves coating deposition efficiency. At the same time, the formed high-entropy alloy silicide coating has good anti-oxidation and diffusion-blocking functions.

[0032] This invention provides an aluminum-modified high-entropy silicide coating prepared by the method described above. The main components of the aluminum-modified high-entropy silicide coating are (NbMoTaW)Si2 and (NbMoTaW)3(Al2Si4).

[0033] The following detailed description of the preparation method of the aluminum-modified high-entropy silicide coating provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1 ① Sample preparation and pretreatment: Weigh 22.5 at% Nb, 22.5 at% Mo, 22.5 at% Ta, 22.5 at% W, and 10 at% Al as ingredients, remove the surface oxide film, and prepare (NbMoTaW) by vacuum arc melting. 90 Al 10The refractory high-entropy alloy ingot is turned over and remelted at least 5 times during the melting process to ensure compositional uniformity. Then, the ingot alloy is cut into small samples of 10×8×3mm, and the six sides are chamfered. The surface of the sample is polished smooth by using 320-grit, 500-grit, 800-grit, and 1000-grit SiC wet sandpaper in sequence. After polishing, the sample is ultrasonically cleaned with deionized water and anhydrous ethanol for 30 minutes in sequence, and then dried in a drying oven at 100℃ for 1 hour for later use.

[0035] ② Preparation of infiltration agent: Select an infiltration agent with a mass percentage of 34% Si-1% B-2.5% NaF-62.5% Al2O3. First, put Si powder, B powder and Al2O3 powder into a vacuum drying oven at 100℃ and dry for 10 hours. Then, use a high-precision balance to weigh each ingredient according to the proportion to prepare the infiltration agent. Then, use a planetary ball mill to slowly ball mill the prepared infiltration agent at 100r / min for 2 hours to make the infiltration agent uniformly mixed. ③ Si embedding: Place the polished sample and infiltrator into a corundum crucible and gently compact it, ensuring the sample is completely filled with infiltrator. Seal the crucible with sealant and allow it to cure in the air for at least 8 hours. Place the sealed crucible in a vacuum tube furnace, evacuate and fill with argon gas. Repeat the above process twice. Set the heating temperature of the tube furnace to 1200℃, with a heating rate not exceeding 5℃ / min and a cooling rate not exceeding 2℃ / min. Maintain a constant temperature of 1200℃ for 5 hours, with argon gas protection throughout. After the tube furnace cools to below 100℃, turn off the argon gas, remove the sample, and ultrasonically clean it with anhydrous ethanol for 30 minutes to remove the outer layer of infiltrator.

[0036] Example 1: The cross-sectional morphology of the embedded coating is as follows Figure 1 As shown, by Figure 1 It can be seen that the coating is well covered, without cracking, and the coating is about 23μm thick.

[0037] Example 2 ① Sample preparation and pretreatment: Weigh 22.5 at% Nb, 22.5 at% Mo, 22.5 at% Ta, 22.5 at% W, and 10 at% Al as ingredients, remove the surface oxide film, and prepare (NbMoTaW) by vacuum arc melting. 90 Al 10 The refractory high-entropy alloy ingot is turned over and remelted at least 5 times during the melting process to ensure compositional uniformity. Then, the ingot alloy is cut into small samples of 10×8×3mm, and the six sides are chamfered. The surface of the sample is polished smooth by using 320-grit, 500-grit, 800-grit, and 1000-grit SiC wet sandpaper in sequence. After polishing, the sample is ultrasonically cleaned with deionized water and anhydrous ethanol for 30 minutes in sequence, and then dried in a drying oven at 100℃ for 1 hour for later use.

[0038] ② Preparation of infiltration agent: Select an infiltration agent with a mass percentage of 34% Si-1% B-2.5% NaF-62.5% Al2O3. First, put Si powder, B powder and Al2O3 powder into a vacuum drying oven at 100℃ and dry for 10 hours. Then, use a high-precision balance to weigh each ingredient according to the proportion to prepare the infiltration agent. Then, use a planetary ball mill to slowly ball mill the prepared infiltration agent at 100r / min for 2 hours to make the infiltration agent uniformly mixed. ③ Si embedding: Place the polished sample and infiltrator into a corundum crucible and gently compact it, ensuring the sample is completely filled with infiltrator. Seal the crucible with sealant and allow it to cure in the air for at least 8 hours. Place the sealed crucible in a vacuum tube furnace, evacuate and fill with argon gas. Repeat the above process twice. Set the tube furnace heating temperature to 1000℃, with a heating rate not exceeding 5℃ / min and a cooling rate not exceeding 2℃ / min. Maintain a constant temperature of 1000℃ for 12 hours, with argon gas protection throughout. After the tube furnace cools to below 100℃, turn off the argon gas, remove the sample, and ultrasonically clean it with anhydrous ethanol for 30 minutes to remove the outer layer of infiltrator.

[0039] The results showed that the coating in Example 2 was well-coated, without cracking, and the coating thickness was approximately 12 μm.

[0040] Example 3 ① Sample preparation and pretreatment: Weigh 20 at% Nb, 20 at% Mo, 20 at% Ta, 20 at% W, and 20 at% Al as ingredients, remove the surface oxide film, and prepare (NbMoTaW) by vacuum arc melting. 80 Al 20 The refractory high-entropy alloy ingot is turned over and remelted at least 5 times during the melting process to ensure compositional uniformity. Then, the ingot alloy is cut into small samples of 10×8×3mm, and the six sides are chamfered. The surface of the sample is polished smooth by using 320-grit, 500-grit, 800-grit, and 1000-grit SiC wet sandpaper in sequence. After polishing, the sample is ultrasonically cleaned with deionized water and anhydrous ethanol for 30 minutes in sequence, and then dried in a drying oven at 100℃ for 1 hour for later use.

[0041] ② Preparation of infiltration agent: Select an infiltration agent with a mass percentage of 34% Si-1% B-2.5% NaF-62.5% Al2O3. First, put Si powder, B powder and Al2O3 powder into a vacuum drying oven at 100℃ and dry for 10 hours. Then, use a high-precision balance to weigh each ingredient according to the proportion to prepare the infiltration agent. Then, use a planetary ball mill to slowly ball mill the prepared infiltration agent at 100r / min for 2 hours to make the infiltration agent uniformly mixed. ③ Si embedding: Place the polished sample and infiltrator into a corundum crucible and gently compact it, ensuring the sample is completely filled with infiltrator. Seal the crucible with sealant and allow it to cure in the air for at least 8 hours. Place the sealed crucible in a vacuum tube furnace, evacuate and fill with argon gas. Repeat the above process twice. Set the tube furnace heating temperature to 1000℃, with a heating rate not exceeding 5℃ / min and a cooling rate not exceeding 2℃ / min. Maintain a constant temperature of 1000℃ for 12 hours, with argon gas protection throughout. After the tube furnace cools to below 100℃, turn off the argon gas, remove the sample, and ultrasonically clean it with anhydrous ethanol for 30 minutes to remove the outer layer of infiltrator.

[0042] Example 3: The cross-sectional morphology of the embedded coating is as follows Figure 2 As shown, by Figure 2 It can be seen that the coating is well covered, without cracking, and the coating is about 10μm thick.

[0043] Example 4 ① Sample preparation and pretreatment: Weigh 20 at% Nb, 20 at% Mo, 20 at% Ta, 20 at% W, and 20 at% Al as ingredients, remove the surface oxide film, and prepare (NbMoTaW) by vacuum arc melting. 80 Al 20 The refractory high-entropy alloy ingot is turned over and remelted at least 5 times during the melting process to ensure compositional uniformity. Then, the ingot alloy is cut into small samples of 10×8×3mm, and the six sides are chamfered. The surface of the sample is polished smooth by using 320-grit, 500-grit, 800-grit, and 1000-grit SiC wet sandpaper in sequence. After polishing, the sample is ultrasonically cleaned with deionized water and anhydrous ethanol for 30 minutes in sequence, and then dried in a drying oven at 100℃ for 1 hour for later use.

[0044] ② Preparation of infiltration agent: Select an infiltration agent with a mass percentage of 34% Si-1% B-2.5% NaF-62.5% Al2O3. First, put Si powder, B powder and Al2O3 powder into a vacuum drying oven at 100℃ and dry for 10 hours. Then, use a high-precision balance to weigh each ingredient according to the proportion to prepare the infiltration agent. Then, use a planetary ball mill to slowly ball mill the prepared infiltration agent at 100r / min for 2 hours to make the infiltration agent uniformly mixed. ③ Si embedding: Place the polished sample and infiltrator into a corundum crucible and gently compact it, ensuring the sample is completely filled with infiltrator. Seal the crucible with sealant and allow it to cure in the air for at least 8 hours. Place the sealed crucible in a vacuum tube furnace, evacuate and fill with argon gas. Repeat the above process twice. Set the tube furnace heating temperature to 1300℃, with a heating rate not exceeding 5℃ / min and a cooling rate not exceeding 2℃ / min. Maintain a constant temperature of 1300℃ for 5 hours, with argon gas protection throughout. After the tube furnace cools to below 100℃, turn off the argon gas, remove the sample, and ultrasonically clean it with anhydrous ethanol for 30 minutes to remove the outer layer of infiltrator.

[0045] Example 4: The cross-sectional morphology of the embedded coating is as follows Figure 3 As shown, the coating is well-coated, without cracking, and the coating thickness is approximately 40 μm.

[0046] Comparative Example 1 The only difference from Example 1 is that Al is not added. The specific steps are as follows: ① Sample preparation and pretreatment: Equimolar amounts of Nb, Mo, Ta, and W were weighed as ingredients, the surface oxide film was removed, and equimolar NbMoTaW refractory high-entropy alloy ingots were prepared by vacuum arc melting. During the melting process, the ingots were turned over and remelted at least 5 times to ensure compositional uniformity. After that, the alloy ingots were cut into small samples of 10×8×3mm, and the six sides were chamfered. The sample surfaces were polished smooth using 320-mesh, 500-mesh, 800-mesh, and 1000-mesh SiC wet sandpaper in sequence. After polishing, the samples were ultrasonically cleaned with deionized water and anhydrous ethanol for 30 minutes in sequence, and then dried in a drying oven at 100℃ for 1 hour for later use.

[0047] ② Preparation of infiltration agent: Select an infiltration agent with a mass percentage of 34% Si-1% B-2.5% NaF-62.5% Al2O3. First, put Si powder, B powder and Al2O3 powder into a vacuum drying oven at 100℃ and dry for 10 hours. Then, use a high-precision balance to weigh each ingredient according to the proportion to prepare the infiltration agent. Then, use a planetary ball mill to slowly ball mill the prepared infiltration agent at 100r / min for 2 hours to make the infiltration agent uniformly mixed. ③ Si embedding: Place the polished sample and infiltrator into a corundum crucible and gently compact it, ensuring the sample is completely filled with infiltrator. Seal the crucible with sealant and allow it to cure in the air for at least 8 hours. Place the sealed crucible in a vacuum tube furnace, evacuate and fill with argon gas. Repeat the above process twice. Set the heating temperature of the tube furnace to 1200℃, with a heating rate not exceeding 5℃ / min and a cooling rate not exceeding 2℃ / min. Maintain a constant temperature of 1200℃ for 5 hours, with argon gas protection throughout. After the tube furnace cools to below 100℃, turn off the argon gas, remove the sample, and ultrasonically clean it with anhydrous ethanol for 30 minutes to remove the outer layer of infiltrator.

[0048] Comparative Example 1: The cross-sectional morphology of the coating after embedding and infiltration is as follows Figure 4 As shown, by Figure 4 It can be seen that both the coating and the substrate are cracked, and silicon diffuses along the grain boundaries into the substrate alloy.

[0049] Comparative Example 2 The difference from Example 1 is the addition of 25 at% Al.

[0050] ① Sample preparation and pretreatment: Weigh 18.75at%Nb, 18.75at%Mo, 18.75at%Ta, 18.75at%W, and 25at%Al as raw materials, remove the surface oxide film, and prepare (NbMoTaW) by vacuum arc melting. 75 Al 25 The refractory high-entropy alloy ingot is turned over and remelted at least 5 times during the melting process to ensure compositional uniformity. Then, the ingot alloy is cut into small samples of 10×8×3mm, and the six sides are chamfered. The surface of the sample is polished smooth by using 320-grit, 500-grit, 800-grit, and 1000-grit SiC wet sandpaper in sequence. After polishing, the sample is ultrasonically cleaned with deionized water and anhydrous ethanol for 30 minutes in sequence, and then dried in a drying oven at 100℃ for 1 hour for later use.

[0051] ② Preparation of infiltration agent: Select an infiltration agent with a mass percentage of 34% Si-1% B-2.5% NaF-62.5% Al2O3. First, put Si powder, B powder and Al2O3 powder into a vacuum drying oven at 100℃ and dry for 10 hours. Then, use a high-precision balance to weigh each ingredient according to the proportion to prepare the infiltration agent. Then, use a planetary ball mill to slowly ball mill the prepared infiltration agent at 100r / min for 2 hours to make the infiltration agent uniformly mixed. ③ Si embedding: Place the polished sample and infiltrator into a corundum crucible and gently compact it, ensuring the sample is completely filled with infiltrator. Seal the crucible with sealant and allow it to cure in the air for at least 8 hours. Place the sealed crucible in a vacuum tube furnace, evacuate and fill with argon gas. Repeat the above process twice. Set the heating temperature of the tube furnace to 1200℃, with a heating rate not exceeding 5℃ / min and a cooling rate not exceeding 2℃ / min. Maintain a constant temperature of 1200℃ for 5 hours, with argon gas protection throughout. After the tube furnace cools to below 100℃, turn off the argon gas, remove the sample, and ultrasonically clean it with anhydrous ethanol for 30 minutes to remove the outer layer of infiltrator.

[0052] Comparative Example 2: The cross-sectional morphology of the coating after embedding and infiltration is as follows Figure 5 As shown, by Figure 5 It is known that when the Al content is too high, the coating will crack.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of producing an aluminum-modified high-entropy silicide coating, characterized by, Includes the following steps: Aluminum-modified high-entropy alloys are prepared by smelting; the composition of the aluminum-modified high-entropy alloys is (NbMoTaW). 1-x Al x Where 0 < x ≤ 0.2, and Nb, Mo, Ta, and W are in equal atomic ratios; The aluminum-modified high-entropy alloy is embedded and infiltrated with Si to obtain the aluminum-modified high-entropy silicide coating; the embedding and infiltrating temperature is 1000~1300℃.

2. The production method according to claim 1, characterized by, The infiltrating agent used for embedding Si, by mass percentage, comprises 20-40% silicon powder, 2-5% activator, 0-1% B powder, and the balance Al2O3.

3. The production method according to claim 2, characterized by, The activator includes NaF or NH4F.

4. The production method according to claim 3, characterized by, The infiltrator comprises 34% silica powder, 2.5% NaF, 1% B powder, and the balance Al2O3.

5. The method of any one of claims 1 to 4, wherein the method further comprises the step of: The heat preservation time for the Si embedding and infiltration is 3~20h.

6. The method of claim 1, wherein, The rate of heating to the temperature of the embedded Si is ≤5℃ / min.

7. The preparation method according to claim 1, characterized in that, The melting process is a vacuum arc melting process.

8. The preparation method according to claim 1, characterized in that, The temperature for embedding and infiltrating Si is 1200℃.

9. The method of claim 1, wherein, 0.05≤x≤0.2。 10. The aluminum-modified high-entropy silicide coating prepared by the preparation method according to any one of claims 1 to 9.

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