A high entropy silicon carbide anti-oxidation coating for Ti3Al-based composite fasteners and preparation method thereof

Abstract

The present invention provides a high-entropy silicon carbide (SiC) anti-oxidation coating for Ti3Al-based composite fasteners and a preparation method thereof. The high-entropy SiC coating comprises metallic elements and non-metallic elements, wherein the metallic elements include Ti, Zr, Nb, Mo, and W, and the non-metallic elements include Si and C. The molar ratio of the metallic elements to the non-metallic elements is 1:1.5-2; the molar ratio of Ti, Zr, Nb, Mo, and W is 1-10:1-10:1-10:1-10:1-10; and the carbon atom content is 10-40% of the total number of atoms in the high-entropy SiC. The present invention introduces a small amount of carbon and silicon vacancies into the high-entropy SiC to promote the outward diffusion of silicon during oxidation, rapidly forming a dense and continuous SiO2 oxide layer on the surface, effectively restricting the inward diffusion of oxygen and improving the oxidation resistance of the high-entropy SiC.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials, and in particular relates to a high-entropy silicon carbide anti-oxidation coating for a Ti3Al-based composite material fastener and a preparation method thereof. Background Art

[0002] Ti3Al alloy is an excellent high-temperature structural material in the temperature range of 600-700℃ due to its low density, high specific strength at high temperature and high-temperature creep resistance. It is widely used in the aerospace field. f SiC / Ti3Al composites have higher specific strength and specific stiffness and lower thermal expansion coefficient than Ti3Al matrix, which further increases its service temperature to 800℃. Compared with ceramic-based high-temperature structural materials, they are more processable and are candidate materials for high-temperature fasteners in aerospace. However, at 800℃, SiC f Due to insufficient Al content, the surface of Ti3Al composite fasteners cannot form a continuous and dense Al2O3 protective layer, resulting in severe oxidation. To prevent the failure of Ti3Al-based composite fasteners in long-term service at 800°C due to oxidation, improving their high-temperature oxidation resistance is an urgent issue to be addressed.

[0003] Existing silicide coatings (such as MoSi2) are widely used as high-temperature protective coatings due to their high melting point, good thermal stability, and strong self-healing ability. Their excellent oxidation resistance is due to their high silicon content. During the oxidation process, Si is preferentially oxidized, easily forming a continuous and dense SiO2 protective layer, thereby preventing further inward diffusion of oxygen, thereby protecting the substrate from oxidation. However, single binary silicide anti-oxidation coatings still have the defects of poor oxidation resistance and poor low-temperature toughness, and urgently need to be further improved to meet the service requirements of Ti3Al composite fasteners at high temperatures. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-entropy silicon carbide anti-oxidation coating for Ti3Al-based composite fasteners and a preparation method thereof. The present invention introduces a small amount of carbon and silicon vacancies into the high-entropy silicide to promote the outward diffusion of silicon during the oxidation process, thereby forming a dense and continuous SiO2 oxide layer on the alloy surface, thereby improving the oxidation resistance and low-temperature toughness.

[0005] In order to achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0006] A high-entropy silicon carbide anti-oxidation coating, comprising metal elements and non-metal elements, wherein the metal elements include Ti, Zr, Nb, Mo and W, and the non-metal elements include Si and C;

[0007] The molar ratio of metal elements to non-metal elements is 1:1.5-2;

[0008] The molar ratio of Ti, Zr, Nb, Mo and W is 1-10:1-10:1-10:1-10:1-10;

[0009] The carbon atom content is 10-40% of the total number of high entropy silicon carbide atoms.

[0010] Preferably, the molar ratio of Si to C is 3:1-4.

[0011] Preferably, the thickness of the high-entropy silicon carbide anti-oxidation coating is 2 to 5 μm.

[0012] The present invention also provides a method for preparing the high-entropy silicon carbide anti-oxidation coating described in the above technical solution, comprising the following steps:

[0013] The target material is deposited on the substrate surface by magnetron sputtering to obtain the high-entropy silicon carbide anti-oxidation coating on the substrate surface; the target material includes a mixture of TiSi2, ZrSi2, NbSi2, MoSi2, WSi2, WC and NbC.

[0014] Preferably, the substrate comprises a Ti3Al sheet or a Ti3Al-based composite material fastener.

[0015] Preferably, the target material installation method includes: stacking and arranging from top to bottom in a vertical direction to form a first composite target and a second composite target; the arrangement order of the first composite target is TiSi2, ZrSi2, NbSi2, MoSi2 and WC, and the arrangement order of the second composite target is WC, MoSi2, NbSi2, ZrSi2 and TiSi2;

[0016] or the arrangement order of the first composite targets is TiSi2, ZrSi2, NbC, MoSi2 and WC, and the arrangement order of the second composite targets is WC, MoSi2, NbC, ZrSi2 and TiSi2;

[0017] The first composite target and the second composite target are arranged opposite to each other;

[0018] The arrangement period of the first composite target and the second composite target is independently 1 to 3.

[0019] Preferably, the parameters of the magnetron sputtering include: the sputtering current of each target is 500-900 mA, the sputtering voltage is 400-600 V, the substrate bias is -50--200 V, the sample holder speed is 150-250 r / h, the back pressure is less than 4×10 -4Pa, the working pressure is 0.5-1.1 Pa, the substrate temperature is 300-500° C., the sputtering time is 40-80 min, and the target-substrate distance is 6-10 cm; the magnetron sputtering is carried out in an argon atmosphere; and the argon gas flow value is 50-70 sccm.

[0020] Preferably, the temperature of the substrate during the magnetron sputtering is 300-500°C.

[0021] The present invention also provides a high entropy silicon carbide anti-oxidation coating for a Ti3Al-based composite material fastener, comprising a Ti3Al-based composite material fastener and a high entropy silicon carbide anti-oxidation coating deposited on the surface of the Ti3Al-based composite material fastener;

[0022] The high-entropy silicon carbide anti-oxidation coating is the high-entropy silicon carbide anti-oxidation coating described in the above technical solution or the high-entropy silicon carbide anti-oxidation coating prepared by the preparation method described in the above technical solution.

[0023] The present invention provides a high-entropy silicon carbide anti-oxidation coating comprising metal elements and non-metal elements, wherein the metal elements include Ti, Zr, Nb, Mo, and W, and the non-metal elements include Si and C; wherein the molar ratio of the metal elements to the non-metal elements is 1:1.5-2; the molar ratio of the Ti, Zr, Nb, Mo, and W is 1-10:1-10:1-10:1-10:1-10; and the carbon atom content is 10-40% of the total number of high-entropy silicon carbide atoms. In the high-entropy silicon carbide anti-oxidation coating of the present invention, the metal elements randomly occupy the cation positions, and the non-metal elements randomly occupy the anion positions. Moreover, because the present invention uses a composite target material composed of disilicide and carbide, Si vacancies are introduced simultaneously with the introduction of C during the subsequent magnetron sputtering process. As a result, the high-entropy silicon carbide anti-oxidation coating promotes the outward diffusion of silicon during oxidation, rapidly forming a dense and continuous SiO2 oxide layer on the surface, effectively restricting the inward diffusion of oxygen and improving the oxidation resistance of the high-entropy silicon carbide. At the same time, the high mixing entropy enhances the thermal stability of the high-entropy silicon carbide anti-oxidation coating, which is beneficial for its long-term service at high temperatures. In addition, the present invention further improves the hardness and low-temperature toughness of the high-entropy silicon carbide through carbon alloying.

[0024] The present invention also provides a method for preparing the high-entropy silicon carbide described in the above technical solution. The target material described in the present invention includes a mixture of multiple elements selected from TiSi2, ZrSi2, NbSi2, MoSi2, WSi2, WC and NbC. The high-entropy silicon carbide anti-oxidation coating is regulated by selecting multiple elements, thereby reducing the difficulty of preparing the multi-component target material, and can conveniently and quickly adjust the component composition of the high-entropy silicon carbide. The preparation method is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 Schematic diagram of the installation of a magnetron sputtering target for preparing a high-entropy silicon carbide anti-oxidation coating according to the present invention;

[0027] Figure 2 Surface EDS images of the low-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 1 and the high-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 2 of the present invention;

[0028] Figure 3 These are SEM cross-sectional images of the Ti3Al coating of Comparative Example 1, the high-entropy silicide coating of Comparative Example 2, the low-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 1, and the high-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 2 after oxidation in air at 800°C for 8h;

[0029] Figure 4 SEM surface images of the Ti3Al of Comparative Example 1, the high-entropy silicide anti-oxidation coating of Comparative Example 2, the low-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 1, and the high-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 2 of the present invention;

[0030] Figure 5 These are the hardness graphs and micron indentation SEM images of the low-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 1 of the present invention and the high-entropy silicide anti-oxidation coating of Comparative Example 2. DETAILED DESCRIPTION

[0031] The present invention provides a high-entropy silicon carbide anti-oxidation coating, comprising metal elements and non-metal elements, wherein the metal elements include Ti, Zr, Nb, Mo and W, and the non-metal elements include Si and C;

[0032] The molar ratio of metal elements to non-metal elements is 1:1.5-2;

[0033] The molar ratio of Ti, Zr, Nb, Mo and W is 1-10:1-10:1-10:1-10:1-10;

[0034] The carbon atom content is 10-40% of the total number of high entropy silicon carbide atoms.

[0035] In the present invention, the molar ratio of metal elements to non-metal elements is 1:1.5-2, and in a specific embodiment, it can be 1:2; the molar ratio of Ti, Zr, Nb, Mo and W is 1-10:1-10:1-10:1-10:1-10, and in a specific embodiment, it can be 3:4:7:8:5; the carbon atom content is 10-40% of the total number of high-entropy silicon carbide atoms, and in a specific embodiment, it can be 17% or 38%.

[0036] In the present invention, the molar ratio of Si to C is 3:1-4.

[0037] In the present invention, the thickness of the high entropy silicon carbide anti-oxidation coating is 2 to 5 μm, and in a specific embodiment, it can be 3 μm or 4 μm.

[0038] The present invention also provides a method for preparing the high-entropy silicon carbide anti-oxidation coating described in the above technical solution, comprising the following steps:

[0039] The target material is deposited on the substrate surface by magnetron sputtering to obtain the high-entropy silicon carbide anti-oxidation coating on the substrate surface; the target material includes a mixture of TiSi2, ZrSi2, NbSi2, MoSi2, WSi2, WC and NbC.

[0040] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0041] In the present invention, the substrate comprises a Ti3Al sheet or a Ti3Al-based composite fastener; the Ti3Al-based composite fastener comprises SiC f reinforcement and Ti3Al matrix.

[0042] In the present invention, the substrate is polished and cleaned in sequence before use; the mesh size of the sandpaper used for polishing is 1000-7000 mesh, and in a specific embodiment, it can be 3000 mesh or 5000 mesh; the cleaning includes a first cleaning and a second cleaning; the first cleaning includes cleaning with acetone, ethanol and deionized water in sequence; the first cleaning method is ultrasonic, and the cleaning time of acetone, ethanol and deionized water in the second cleaning is independently 20-40 minutes; the second cleaning includes acid cleaning and deionized water cleaning in sequence; the reagent used for the acid cleaning is HF solution; the concentration of the HF solution is 0.5-1wt%, and the acid cleaning time is 30-60 seconds; the deionized water cleaning time in the second cleaning is 20-40 minutes.

[0043] In the present invention, each target material is a bar target with a size of 10 to 150 mm*75 mm*8 mm. In a specific embodiment, the size can be 10 mm*75 mm*8 mm.

[0044] In the present invention, the target material installation method includes: stacking and arranging from top to bottom in the vertical direction to form a first composite target and a second composite target; the arrangement order of the first composite target is TiSi2, ZrSi2, NbSi2, MoSi2 and WC, and the arrangement order of the second composite target is WC, MoSi2, NbSi2, ZrSi2 and TiSi2; or the arrangement order of the first composite target is TiSi2, ZrSi2, NbC, MoSi2 and WC, and the arrangement order of the second composite target is WC, MoSi2, NbC, ZrSi2 and TiSi2; the first composite target and the second composite target are arranged relative to each other; the arrangement period of the first composite target and the second composite target is independently 1 to 3, and in a specific embodiment, it can be 1, 2 or 3.

[0045] In the present invention, in addition to the above-mentioned TiSi2, ZrSi2, NbSi2, MoSi2, WSi2, WC and NbC targets, other transition metal silicide and carbide targets can also be selected for splicing.

[0046] In the present invention, the parameters of the magnetron sputtering include: target sputtering current of 500-900 mA, in a specific embodiment, it can be 695 mA, 707 mA or 709 mA; sputtering voltage of 400-600 V, in a specific embodiment, it can be 495 V, 500 V or 550 V; substrate bias of 0-200 V, in a specific embodiment, it can be 100 V or 150 V; sample holder rotation speed of 100-200 r / h, in a specific embodiment, it can be 150 r / h or 180 r / h; back pressure of less than 4×10 -4 Pa; the working pressure is 0.5-1.1 Pa, and in a specific embodiment, it can be 0.8 Pa, 0.9 Pa or 1.0 Pa; the substrate temperature is 300-500°C, and in a specific embodiment, it can be 350°C, 400°C or 450°C; the sputtering time is 40-80 min, and in a specific embodiment, it can be 60 min or 70 min; the target-substrate distance is 6-10 cm, and in a specific embodiment, it can be 7 cm or 8 cm; the magnetron sputtering is carried out in an argon atmosphere; the gas flow value of the argon is 50-70 sccm, and in a specific embodiment, it can be 60 sccm.

[0047] In an embodiment of the present invention, the magnetron sputtering operation steps include: closing the vacuum chamber door, evacuating the vacuum chamber to a pressure less than 4×10 -4Pa; turn on the heating power supply to raise the temperature to 300-500°C, open the gas valve, introduce argon gas, set the argon gas flow value to 50-70 sccm, adjust the gate valve so that the working pressure in the vacuum coating chamber is 0.5-1.1 Pa, adjust the substrate holder rotation speed to 150-250 r / h, turn on the ion source power supply, and sputter and clean for 20-40 minutes. After the ion source cleaning is completed, adjust the argon gas flow value back to 50-70 sccm, adjust the gate valve so that the working pressure in the vacuum coating chamber is 0.5-1.1 Pa; adjust the target material sputtering current to 600-800 mA, the sputtering voltage to 400-600 V, the substrate bias value to -50--200 V, and sputter for 40-80 minutes; after the deposition is completed, turn off the composite target sputtering power supply, stop introducing argon gas, adjust the gate valve to the maximum, and when the temperature in the vacuum chamber drops to room temperature, the high entropy silicon carbide anti-oxidation coating is obtained on the substrate surface;

[0048] The present invention also provides a high entropy silicon carbide anti-oxidation coating for a Ti3Al-based composite material fastener, which is characterized by comprising a Ti3Al-based composite material fastener and a high entropy silicon carbide anti-oxidation coating deposited on the surface of the Ti3Al-based composite material fastener;

[0049] The high-entropy silicon carbide anti-oxidation coating is the high-entropy silicon carbide anti-oxidation coating described in the above technical solution or the high-entropy silicon carbide anti-oxidation coating prepared by the preparation method described in the above technical solution.

[0050] The high entropy silicon carbide anti-oxidation coating of the Ti3Al-based composite fastener of the present invention can be applied in the field of aerospace.

[0051] To further illustrate the present invention, a high-entropy silicon carbide anti-oxidation coating for a Ti3Al-based composite fastener and a preparation method thereof provided by the present invention are described in detail below with reference to the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0052] Example 1

[0053] The Ti3Al composite fasteners were polished in a metal polishing machine with 1000-mesh, 3000-mesh, 5000-mesh, and 7000-mesh sandpapers in sequence until the surface was smooth and free of obvious scratches. The polished Ti3Al sheets were ultrasonically treated in acetone, ethanol, and deionized water for 20 minutes, then pickled with 1% HF solution for 30 seconds, ultrasonically cleaned with deionized water for 20 minutes, and dried to obtain pretreated Ti3Al composite fasteners.

[0054] The pretreated Ti3Al composite fasteners were fixed on a rectangular sample holder and placed in the sample chamber of a multi-target magnetron sputtering device. TiSi2, ZrSi2, NbSi2, MoSi2, and WC strip targets with sizes of 10mm*75mm*8mm were stacked vertically from top to bottom for three cycles and installed at target position A. WC, MoSi2, NbSi2, ZrSi2, and WC were stacked vertically in the opposite order. i2 , TiSi2 is arranged in 3 cycles and installed at the relative B target position. The installation position is as follows Figure 1 As shown, adjust the target-substrate distance to 10 cm; after preparation, close the vacuum chamber door and evacuate to less than 4×10 -4 Pa. Once the vacuum level reached the required level, the heating power was turned on and the temperature was raised to 500°C. The gas line valve was opened to introduce argon gas, setting the argon flow rate to 60 sccm. The gate valve was adjusted to maintain the operating pressure in the vacuum coating chamber at 0.8 Pa. The substrate holder rotation speed was adjusted to 200 r / h, the ion source power was turned on, and sputtering was performed for 20 minutes. After the ion source was cleaned, the argon flow rate was returned to 60 sccm, the gate valve was adjusted to maintain the operating pressure in the vacuum coating chamber at 0.8 Pa, the sputtering power was turned on, and the composite target current was adjusted to 707 mA, the sputtering voltage to 500 V, and the substrate bias to -100 V. Sputtering was continued for 60 minutes. After deposition was completed, the composite target sputtering power was turned off, the gas line valve was closed, and the sample was removed when the vacuum chamber temperature returned to room temperature. A low-carbon, high-entropy silicon carbide oxidation-resistant coating was obtained on the Ti3Al composite fastener.

[0055] Example 2

[0056] The Ti3Al sheet was polished in a metal polishing machine with 1000 mesh, 3000 mesh, 5000 mesh, and 7000 mesh sandpaper in sequence until the surface was smooth and free of obvious scratches. The polished Ti3Al sheet was ultrasonically treated in acetone, ethanol, and deionized water for 20 min, then pickled with 1% HF solution for 30 s, ultrasonically cleaned with deionized water for 20 min, and dried to obtain a pretreated Ti3Al sheet.

[0057] Fix the pretreated Ti3Al sheet on a rectangular sample holder and place it in the sample chamber of the multi-target magnetron sputtering equipment. Arrange the TiSi2, ZrSi2, NbC, MoSi2, and WC strip targets of size 10mm*75mm*8mm in sequence vertically from top to bottom for 3 cycles and install them at target position A. Arrange WC, MoSi2, NbC, ZrSi2, and TiSi2 in the opposite order vertically for 3 cycles and install them at the opposite target position B. The installation positions are as follows: Figure 1 As shown, adjust the target-substrate distance to 10 cm; after preparation, close the vacuum chamber door and evacuate to less than 4×10 -4Pa. Once the vacuum reaches the required level, the heating power is turned on and the temperature is raised to 500°C. The gas valve is opened to introduce argon gas, setting the argon flow rate to 60 sccm. The gate valve is adjusted to maintain the operating pressure in the vacuum coating chamber at 0.8 Pa. The substrate holder rotation speed is adjusted to 200 rpm, the ion source power is turned on, and sputtering is performed for 20 minutes. After the ion source is cleaned, the argon flow rate is returned to 60 sccm, the gate valve is adjusted to maintain the operating pressure in the vacuum coating chamber at 0.8 Pa, the sputtering power is turned on, the composite target current is adjusted to 709 mA, and the sputtering voltage is adjusted to 495 V. Sputtering is continued for 60 minutes. After deposition is completed, the composite target sputtering power is turned off, the gas valve is closed, and the sample is removed when the vacuum chamber temperature drops to room temperature. A high-carbon, high-entropy silicon carbide, anti-oxidation coating is obtained on the surface of the Ti3Al wafer.

[0058] Comparative Example 1

[0059] The Ti3Al sheet was polished in a metal polishing machine with 1000 mesh, 3000 mesh, 5000 mesh, and 7000 mesh sandpaper in sequence until the surface was smooth and free of obvious scratches. The polished Ti3Al sheet was placed in acetone, ethanol, and deionized water for ultrasonic treatment for 20 minutes, then pickled with 1% HF solution for 30 seconds, and then ultrasonically cleaned with deionized water for 20 minutes and dried to obtain a pretreated Ti3Al sheet.

[0060] Comparative Example 2

[0061] The Ti3Al sheet was polished in a metal polishing machine with 1000 mesh, 3000 mesh, 5000 mesh, and 7000 mesh sandpaper in sequence until the surface was smooth and free of obvious scratches. The polished Ti3Al sheet was ultrasonically treated in acetone, ethanol, and deionized water for 20 min, then pickled with 1% HF solution for 30 s, ultrasonically cleaned with deionized water for 20 min, and dried to obtain a pretreated Ti3Al sheet.

[0062] Fix the pretreated Ti3Al sheet on a rectangular sample holder and place it in the sample chamber of the multi-target magnetron sputtering equipment; arrange the TiSi2, ZrSi2, NbSi2, MoSi2, and WSi2 strip targets of size 10mm*75mm*8mm in sequence from top to bottom in three cycles in the vertical direction and install them in the target position A; arrange WSi2, MoSi2, NbSi2, ZrSi2, and TiSi2 in the opposite order in the vertical direction for three cycles and install them in the opposite target position B. The installation positions are as follows: Figure 1 As shown, adjust the target-base distance to 10 cm.

[0063] After the preparation is completed, close the vacuum chamber door and evacuate the chamber to a vacuum degree of less than 4×10 -4Pa; after the required vacuum level is reached, the heating power is turned on and the temperature is raised to 500°C. The gas valve is opened to introduce argon gas, with the argon flow rate set to 60 sccm. The gate valve is adjusted to maintain the operating pressure in the vacuum coating chamber at 0.8 Pa. The substrate holder rotation speed is adjusted to 200 rpm, the ion source power is turned on, and sputter cleaning is performed for 20 minutes. After the ion source cleaning is completed, the argon flow rate is returned to 60 sccm, and the gate valve is adjusted to maintain the operating pressure in the vacuum coating chamber at 0.8 Pa. The composite target sputtering current is adjusted to 695 mA, the sputtering voltage is 503 V, and the substrate bias is -100 V. Sputtering is performed for 60 minutes. After deposition is completed, the composite target sputtering power is turned off, the argon flow is stopped, and the gate valve is adjusted to its maximum value. When the vacuum chamber temperature drops to room temperature, the sample is removed, resulting in a high-entropy silicide anti-oxidation coating on the Ti3Al wafer surface.

[0064] Test Case

[0065] High-temperature oxidation experiments were conducted on the pretreated Ti3Al sheets and Ti3Al-based composite fasteners / Ti3Al sheet samples deposited with high-entropy silicon carbide anti-oxidation coatings prepared in Examples 1 and 2 and Comparative Examples 1 and 2. The specific steps were as follows:

[0066] The sample was placed in a crucible in a tube furnace. An alumina insulation plug was placed at the seal, the flange was tightened, and the end was vented to air. The furnace was programmed to heat from room temperature to 800°C at a rate of 10°C / min and then held for 8 hours to simulate oxidation conditions in air. After oxidation, the furnace was turned off, the sample cooled to room temperature, and then tested. The results are shown below.

[0067] Figure 2 The surface EDS images of the low carbon content high entropy silicon carbide anti-oxidation coating of Example 1 and the high carbon content high entropy silicon carbide anti-oxidation coating of Example 2 of the present invention, wherein (a) and (b) are the surface EDS images of the high entropy silicon carbide anti-oxidation coating of Example 1 and Example 2, respectively. Figure 2 It can be seen that the present invention successfully prepared a high-entropy silicon carbide antioxidant coating with multiple components.

[0068] Figure 3 These are SEM cross-sectional images of the Ti3Al coating of Comparative Example 1, the high-entropy silicide coating of Comparative Example 2, the low-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 1, and the high-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 2 after oxidation in air at 800°C for 8h; Figure 4 SEM surface images of the Ti3Al of Comparative Example 1, the high-entropy silicide anti-oxidation coating of Comparative Example 2, the low-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 1, and the high-carbon-content high-entropy silicon carbide anti-oxidation coating of Example 2 of the present invention; Figure 3 and Figure 4(a) are the cross-sectional and surface SEM images of Ti3Al of comparative example 1, (b) are the cross-sectional and surface SEM images of high entropy silicide anti-oxidation coating of comparative example 2, (c) are the cross-sectional and surface SEM images of high entropy silicon carbide anti-oxidation coating of low carbon content of embodiment 1, and (d) are the cross-sectional and surface SEM images of high entropy silicon carbide anti-oxidation coating of high carbon content of embodiment 2. Figures 3-4 It can be seen that the surface of the Ti3Al substrate that has only been pretreated is covered with a thick loose oxide layer, which is about 6.16 μm thick and has a surface roughness of 105 nm. A large number of holes appear on the oxidized surface, which indicates that the Ti3Al substrate undergoes severe oxidation at 800 ° C; the thickness of the low-carbon content high-entropy silicon carbide anti-oxidation coating in Comparative Example 2 is 596 nm, and the surface roughness is 8.49 nm. The thickness of the oxide layer is significantly reduced compared with Comparative Example 1. This is because the silicon element in the high-entropy silicide anti-oxidation coating is preferentially oxidized to form a denser SiO2 layer, thereby hindering the further diffusion of oxygen; the oxide layer thickness of the low-carbon content high-entropy silicon carbide anti-oxidation coating in Example 1 is 474 nm, and the surface roughness is 8.49 nm. The thickness of the oxide layer is 6.88 nm, which is slightly reduced compared with Comparative Example 2, and the oxide layer is more uniform and dense; the thickness of the high-carbon content and high-entropy silicon carbide anti-oxidation coating in Example 2 is 615 nm, and metal oxide particles are formed on the surface. The surface roughness is 37.8 nm. As the carbon content further increases, the oxidation resistance of the high-entropy silicon carbide decreases. Therefore, in the high-entropy silicon carbide anti-oxidation coating, a small amount of carbon atoms with strong affinity for metal elements and silicon vacancies introduced at the anion position promote the diffusion of silicon to the surface, inhibit the formation of metal oxides, and quickly form a continuous and dense SiO2 layer in the early stage of oxidation, which hinders the further inward diffusion of oxygen and improves the oxidation resistance to a certain extent.

[0069] Figure 5 The hardness diagram and micron indentation SEM diagram of the low carbon content high entropy silicon carbide anti-oxidation coating of Example 1 of the present invention and the high entropy silicide anti-oxidation coating of Comparative Example 2 are shown, wherein (a) is the hardness diagram of the high entropy silicon carbide anti-oxidation coating of Example 1 and the high entropy silicide anti-oxidation coating of Comparative Example 2, (b) is the SEM diagram of the high entropy silicide anti-oxidation coating of Comparative Example 2, and (c) is the SEM diagram of the low carbon content high entropy silicon carbide anti-oxidation coating of Example 1. Figure 5It can be seen that the high-entropy silicon carbide anti-oxidation coating obtained in this embodiment was subjected to hardness testing and SEM characterization at the micron indentation. As shown in (a), the hardness of the high-entropy silicide anti-oxidation coating of Comparative Example 2 is 19.5GPa; the modulus is 156.2Gpa. From the micron indentation SEM image (b), more obvious cracks began to appear in Comparative Example 2. This is due to the high content of Si-Si bonds in the high-entropy silicide, which causes the coating to be more brittle. The hardness of the low-carbon content high-entropy silicon carbide anti-oxidation coating obtained in Example 1 of the present invention is 24GPa, and the modulus is 212.51Gpa. From the indentation SEM image (c), the high-entropy silicon carbide anti-oxidation coating of Example 1 of the present invention is almost free of cracks, which indicates that the hardness and toughness of the high-entropy silicon carbide anti-oxidation coating are improved compared to the corresponding high-entropy silicide anti-oxidation coating.

[0070] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high entropy silicon carbide anti-oxidation coating, characterized in that: The following steps are involved: Depositing the target material on the substrate surface by magnetron sputtering to obtain the high entropy silicon carbide anti-oxidation coating on the substrate surface; The target installation method includes: stacking and arranging the target materials from top to bottom in a vertical direction to form a first composite target and a second composite target; the arrangement order of the first composite target is TiSi2, ZrSi2, NbSi2, MoSi2 and WC, and the arrangement order of the second composite target is WC, MoSi2, NbSi2, ZrSi2 and TiSi2; or the arrangement order of the first composite targets is TiSi2, ZrSi2, NbC, MoSi2 and WC, and the arrangement order of the second composite targets is WC, MoSi2, NbC, ZrSi2 and TiSi2; The first composite target and the second composite target are arranged opposite to each other; The arrangement period of the first composite target and the second composite target is independently 1 to 3.

2. The preparation method according to claim 1, characterized in that The substrate includes a Ti3Al sheet or a Ti3Al-based composite material fastener.

3. The preparation method according to claim 1, characterized in that The parameters of the magnetron sputtering include: the sputtering current of each target is 500~900mA, the sputtering voltage is 400~600V, the substrate bias is -50~-200V, the sample holder speed is 150~250r / h, and the back pressure is less than 4×10 -4 Pa, the working pressure is 0.5~1.1Pa, the substrate temperature is 300~500℃, the sputtering time is 40~80min, and the target-substrate distance is 6~10cm; the magnetron sputtering is carried out in an argon atmosphere; the argon gas flow value is 50~70sccm.

4. The preparation method according to claim 1, characterized in that The temperature of the substrate during the magnetron sputtering is 300-500°C.

5. The high entropy silicon carbide anti-oxidation coating prepared by the preparation method according to any one of claims 1 to 4, characterized in that: including metal elements and non-metal elements, wherein the metal elements include Ti, Zr, Nb, Mo and W, and the non-metal elements include Si and C; The molar ratio of metal elements to non-metal elements is 1:1.5~2; The molar ratio of Ti, Zr, Nb, Mo and W is 1-10:1-10:1-10:1-10:1-10; The carbon atom content is 10-40% of the total number of high entropy silicon carbide atoms.

6. The high entropy silicon carbide anti-oxidation coating according to claim 5, characterized in that: The molar ratio of Si to C is 3:1-4.

7. The high entropy silicon carbide anti-oxidation coating according to claim 5, characterized in that: The thickness of the high entropy silicon carbide anti-oxidation coating is 2-5 μm.

8. A high entropy silicon carbide anti-oxidation coating for a Ti3Al-based composite fastener, characterized in that: It comprises a Ti3Al-based composite material fastener and a high entropy silicon carbide anti-oxidation coating deposited on the surface of the Ti3Al-based composite material fastener; The high-entropy silicon carbide anti-oxidation coating is a high-entropy silicon carbide anti-oxidation coating prepared by the preparation method according to any one of claims 1 to 4.

Images