A SiC f Anti-oxidation coating for Ti3Al matrix fastener and method of making

Abstract

The application belongs to the technical field of high-entropy materials, and particularly relates to an oxidation-resistant coating of a SiC f / Ti3Al composite fastener and a preparation method thereof. The application provides a high-entropy silicon boride containing metal elements and non-metal elements; the metal elements include Zr, Nb, Mo and W; the non-metal elements include Si and B; the molar ratio of the metal elements and the non-metal elements is 1:1.5-2; the molar ratio of the Zr, Nb, Mo and W is 5-40:5-40:5-40:5-40; the atomic content of B in the non-metal elements is 5-25 at.%. In a high-temperature environment, the product B2O3 of the oxidation of the boron element can combine with SiO2 to generate borosilicate glass phase, form a continuous and dense oxidation layer, and improve the oxidation resistance. In addition, the toughness is also obviously improved, and the SiC f / Ti3Al composite fastener can meet the oxidation resistance requirement in service.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-entropy materials, and particularly relates to an oxidation-resistant coating of a SiC f / Ti3Al composite fastener and a preparation method thereof. BACKGROUND

[0002] Ti-Al intermetallic compounds have many excellent properties, such as high strength and elastic modulus, good high-temperature creep resistance, and the like. Ti3Al alloy is one of the most widely used Ti-Al intermetallic compounds. Ti3Al alloy can be used as an excellent high-temperature structural material at a temperature range of 600-800 DEG C for a long time, but when serving in a high-temperature environment above 800 DEG C, a non-protective metal oxide TiO2 is easily generated on the surface of the Ti3Al matrix, which causes the surface to be difficult to form a dense and continuous Al2O3 oxide layer, so that the oxidation resistance of the Ti3Al matrix is poor and the Ti3Al matrix is seriously eroded, thereby limiting the application of SiC f / Ti3Al composite material in a high-temperature environment.

[0003] Coating technology is mainly to realize the blockage of external oxygen through a coating to avoid the erosion of the protected matrix. Among them, silicide ceramic coating is a research and application hotspot, and the oxidation resistance mainly comes from the continuous and dense SiO2 oxide layer generated on the surface of the coating by the reaction of silicon and oxygen, so as to hinder the further erosion of oxygen to the inside. At the same time, the flowability of SiO2 at high temperature can compensate for the cracks and pores generated on the surface of the coating during oxidation.

[0004] However, the silicide ceramic coating also has some defects, such as when the environmental temperature is lower than 1000 DEG C, the SiO2 glass generated on the surface of the coating during oxidation has a large viscosity and poor flowability, which limits the healing ability of cracks and pores, and the silicide has the problems of high brittleness and poor toughness. Therefore, it cannot well meet the oxidation resistance requirements of SiC f / Ti3Al composite fastener at high temperature. SUMMARY

[0005] The application aims to provide an oxidation-resistant coating of a SiC f / Ti3Al composite fastener and a preparation method thereof. The high-entropy silicide boride provided by the application has excellent toughness, high-temperature stability and high-temperature oxidation resistance, and can meet the oxidation resistance requirements of SiC f / Ti3Al composite fastener at high temperature.

[0006] In order to achieve the above-mentioned purpose, the application provides the following technical scheme:

[0007] The application provides a high-entropy silicide, comprising metal elements and non-metal elements; the metal elements comprise Zr, Nb, Mo and W; and the non-metal elements comprise Si and B.

[0008] The molar ratio of the metal elements to the non-metal elements is 1:1.5-2.

[0009] The molar ratio of the Zr, Nb, Mo and W is 5-40:5-40:5-40:5-40.

[0010] The atomic content of B in the non-metal elements is 5-25 at.%.

[0011] The application further provides a preparation method of the high-entropy silicide.

[0012] The composite target is deposited on the surface of a substrate by magnetron sputtering in an argon environment to obtain the high-entropy silicide; the material of the composite target comprises MoSi2, WSi2 and NbSi2, and further comprises two or more of ZrSi2, ZrB2 and SiB6.

[0013] Preferably, the composite target is spliced by 3-5 groups of target materials; each group of target materials independently comprises 5-6 small target materials; and each group of target materials independently comprises a MoSi2 target, a WSi2 target and a NbSi2 target, and further comprises two or more of a ZrSi2 target, a ZrB2 target and a SiB6 target.

[0014] Preferably, the conditions of the magnetron sputtering comprise: the working pressure is 0.6 Pa-1.2 Pa, the bias voltage is-50--150 V, the number of target positions is 2-4, and the distance between the substrate and the composite target is 8-12 cm; the magnetron sputtering uses a direct current power supply, the sputtering voltage is 200-500 V, and the sputtering current is 0.6-2 A.

[0015] Preferably, the temperature of the substrate is 350-650 DEG C.

[0016] The application further provides a SiC f / Ti3Al composite fastener, comprising a SiC f / Ti3Al composite fastener base body and an oxidation-resistant coating layer deposited on the surface of the SiC f / Ti3Al composite fastener base body; the material of the oxidation-resistant coating layer is the high-entropy silicide in the above technical solution or the high-entropy silicide obtained by the preparation method in the above technical solution.

[0017] Preferably, the thickness of the oxidation-resistant coating layer is 2-5 mu m.

[0018] The application also provides the high-entropy silicide boride, the high-entropy silicide boride obtained by the preparation method or the SiC f Application of / Ti3Al composite fastener in aerospace materials.

[0019] The application provides a high-entropy silicide boride, which comprises metal elements and nonmetal elements; the metal elements comprise Zr, Nb, Mo and W; the nonmetal elements comprise Si and B; the molar ratio of the metal elements and the nonmetal elements is 1:1.5-2; the molar ratio of the Zr, Nb, Mo and W is 5-40:5-40:5-40:5-40; and the atomic content of B in the nonmetal elements is 5-25 at.%. Based on the multi-component high-entropy silicide, the high-entropy silicide boride is formed by introducing the B element; in a high-temperature environment, the Si atoms are preferentially oxidized to generate a dense SiO2 oxide layer on the surface, thereby hindering the further penetration of oxygen into the interior. The product B2O3 of high-temperature oxidation of the B element can combine with the SiO2 glass to form a borosilicate (SiO2.B2O3) glass phase, which has low viscosity and high flowability, can not only form a continuous and dense oxide layer on the surface more quickly, but also can repair cracks and holes generated on the surface in the high-temperature oxidation process; the metal elements are all refractory alloy elements, and have better stability at high temperatures. Meanwhile, the high-entropy silicide boride has obviously improved toughness compared with the high-entropy silicide. The high-entropy silicide boride provided by the application meets the oxidation resistance requirement of the SiC f / Ti3Al composite fastener when serving in a high-temperature environment. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0021] Figure 1 The schematic diagram of the splicing mode of the composite target of the present application;

[0022] Figure 2 The schematic diagram of the preparation of the oxidation-resistant coating by magnetron sputtering of the present application;

[0023] Figure 3 The SiC f / Ti3Al composite fastener, the Ti3Al sheet obtained in Comparative Example 1 and the SiC fCross-sectional SEM images of / Ti3Al composite fastener after high-temperature oxidation test, wherein a corresponds to Comparative Example 1, b corresponds to Comparative Example 2, c corresponds to Example 1, and d corresponds to Example 2;

[0024] Figure 4 SiC of the deposited oxidation-resistant coating obtained in Examples 1-2 f SiC of / Ti3Al composite fastener, Ti3Al sheet obtained in Comparative Example 1, and deposited high-entropy silicide coating obtained in Comparative Example 2 f Surface SEM images of / Ti3Al composite fastener after high-temperature oxidation test, wherein a corresponds to Comparative Example 1, b corresponds to Comparative Example 2, c corresponds to Example 1, and d corresponds to Example 2;

[0025] Figure 5 SiC of the deposited oxidation-resistant coating obtained in Examples 1-2 f SiC of / Ti3Al composite fastener and deposited high-entropy silicide coating obtained in Comparative Example 2 f Surface SEM images of / Ti3Al composite fastener after indentation test, wherein a corresponds to Comparative Example 2, b corresponds to Example 1, and c corresponds to Example 2. DETAILED DESCRIPTION

[0026] The present application provides a high-entropy silicide boride, comprising metal elements and non-metal elements; the metal elements comprise Zr, Nb, Mo and W; and the non-metal elements comprise Si and B;

[0027] The molar ratio of the metal elements and the non-metal elements is 1:1.5-2;

[0028] The molar ratio of the Zr, Nb, Mo and W is 5-40:5-40:5-40:5-40;

[0029] The atomic content of B in the non-metal elements is 5-25 at. %.

[0030] In the present application, all raw material components are commercially available products well known to those skilled in the art, unless otherwise specified.

[0031] In the present application, the molar ratio of the metal elements and the non-metal elements is 1:1.5-2, and in specific embodiments, can be 1:2.

[0032] In the present application, the molar ratio of the Zr, Nb, Mo and W is 5-40:5-40:5-40:5-40, and in specific embodiments, can be 20:10:10:10 or 20:35:35:35.

[0033] In the present application, the atomic content of B in the non-metallic element is 5-25 at.%, and in specific embodiments, it can be 15 at.%.

[0034] Compared with the traditional silicide coating, the high-entropy silicide coating has high melting point and good thermal stability. In oxidation, it shows the preferential oxidation of Si atoms, avoids the emergence of single metal oxide to destroy the dense oxide layer, and thus leads to the failure of oxidation protection, so the high-entropy silicide coating is more likely to form a continuous and dense SiO2 oxide layer on the surface, thereby improving the overall oxidation resistance of the coating. In order to further improve its oxidation resistance and mechanical properties, the present application introduces B element to form high-entropy silicide on the basis of multi-component high-entropy silicide. In a high-temperature environment, the Si atoms in it are preferentially oxidized to generate a dense SiO2 oxide layer on the surface, which hinders the further penetration of oxygen into the interior. And the product B2O3 of boron element high-temperature oxidation can combine with SiO2 glass to form borosilicate (SiO2·B2O3) glass phase, which has low viscosity and high flowability, has good crack healing ability, not only can form a continuous and dense oxide layer on the surface faster, but also can repair the cracks and pores generated on the surface during high-temperature oxidation, which can effectively prevent the penetration of oxygen; the metal elements are all refractory alloy elements, which have better stability at high temperature. At the same time, the toughness of high-entropy silicide is obviously improved compared with high-entropy silicide. The high-entropy silicide provided by the present application meets the oxidation resistance requirements of SiC f / Ti3Al composite fasteners when serving in a high-temperature environment.

[0035] The present application also provides a preparation method of the high-entropy silicide provided in the above technical solution, which comprises the following steps:

[0036] In an argon environment, the composite target is deposited on the surface of the substrate by magnetron sputtering to obtain the high-entropy silicide coating; the material of the composite target comprises MoSi2, WSi2 and NbSi2, and further comprises two or more of ZrSi2, ZrB2 and SiB6.

[0037] In the present application, the composite target is spliced by 3-5 groups of target materials, and in specific embodiments, it can be 3 groups or 4 groups; each group of target materials independently comprises 5-6 small target materials; each group of target materials independently comprises a MoSi2 target, a WSi2 target and a NbSi2 target, and further comprises two or more of a ZrSi2 target, a ZrB2 target and a SiB6 target, and in specific embodiments, it can be a MoSi2 target, a WSi2 target, a NbSi2 target, a ZrSi2 target and a ZrB2 target; the arrangement order of the small target materials in each group of target materials can be the same; the small target materials are independently rectangular targets with specifications of 10-15 mm x 75-100 mm x 8-10 mm, and in specific embodiments, they can be 10 mm x 75 mm x 8 mm or 12 mm x 80 mm x 8 mm.

[0038] In the application, the substrate is placed on a sample holder; the sample holder can revolve around the main shaft while rotating; the rotation rate of the substrate is 3-10 r / min, in specific embodiments, it can be 5 r / min or 8 r / min; the revolving rate is 2-5 r / min, in specific embodiments, it can be 2 r / min or 3 r / min.

[0039] In the application, the magnetron sputtering can further include cleaning and drying in sequence before the magnetron sputtering; the cleaning includes pickling and ultrasonic cleaning in sequence; the reagent for the pickling is hydrofluoric acid solution; the mass percentage concentration of the hydrofluoric acid solution is 0.5%-1%, in specific embodiments, it can be 0.5% or 0.8%; the pickling mode is immersion, and the time is 0.5-2 min, in specific embodiments, it can be 1 min; the reagent for the ultrasonic cleaning is acetone, anhydrous ethanol and deionized water, in specific embodiments, the cleaning can be performed in sequence with acetone, anhydrous ethanol and deionized water; the single time for the ultrasonic cleaning is 20-30 min, in specific embodiments, it can be 25 min; the drying temperature is 40-60℃, in specific embodiments, it can be 50℃; the time is 1-2 h, in specific embodiments, it can be 1.5 h.

[0040] In the application, the magnetron sputtering further includes vacuumizing, argon feeding and ion source cleaning in sequence before the magnetron sputtering; the vacuum degree of the vacuumizing is ≤4×10 -4 Pa, in specific embodiments, it can be 4×10 -4 Pa; the flow rate of the argon feeding is 40-80 sccm, in specific embodiments, it can be 50 sccm or 70 sccm; the time for the ion source cleaning is 15-30 min.

[0041] In the application, the conditions for the magnetron sputtering include: the working pressure is 0.6-1.2 Pa, in specific embodiments, it can be 0.8 Pa or 1 Pa; the bias voltage is -50--150 V, in specific embodiments, it can be -100 V; the number of target sites is 2-4, in specific embodiments, it can be 3; the distance between the substrate and the composite target is 8-12 cm, in specific embodiments, it can be 9 cm or 11 cm; the magnetron sputtering uses a direct current power supply, the sputtering voltage is 200-500 V, in specific embodiments, it can be 300 V or 400 V; the sputtering current is 0.6-2 A, in specific embodiments, it can be 1 A or 1.5 A.

[0042] In the application, the temperature of the substrate is 350-650℃, in specific embodiments, it can be 400℃, 500℃ or 600℃.

[0043] The preparation method of the high-entropy silicide boride provided by the application utilizes a magnetron sputtering technology, and a composite target formed by arranging and splicing multiple ceramic targets is used to uniformly deposit a high-entropy silicide boride coating on a substrate surface.

[0044] The application further provides a SiC f / Ti3Al composite fastener, which comprises a SiC f / Ti3Al composite fastener substrate and an oxidation-resistant coating deposited on the surface of the SiC f / Ti3Al composite fastener substrate; the material of the oxidation-resistant coating is the high-entropy silicide boride in the above technical solution or the high-entropy silicide boride obtained by the preparation method in the above technical solution.

[0045] In the application, the thickness of the oxidation-resistant coating is 2-5 μm, and in specific embodiments, can be 3 or 4 μm.

[0046] The application further provides the application of the high-entropy silicide boride in the above technical solution, the high-entropy silicide boride obtained by the preparation method in the above technical solution or the SiC f / Ti3Al composite fastener in aerospace materials.

[0047] The application does not have any special limitation on the application process of the high-entropy silicide boride or the SiC f / Ti3Al composite fastener in aerospace materials, and a manner well known to those skilled in the art can be adopted.

[0048] In order to further illustrate the application, the oxidation-resistant coating of the SiC f / Ti3Al composite fastener and the preparation method thereof provided by the application are described in detail below with reference to the accompanying drawings and embodiments, but they should not be understood as limiting the protection scope of the application.

[0049] Example 1

[0050] The SiC f / Ti3Al composite fastener is soaked in a hydrofluoric acid solution for 0.5 min, taken out, wiped dry and then placed in an acetone solution, cleaned in an ultrasonic cleaning machine for 25 min, ultrasonically cleaned in an anhydrous ethanol solution for 25 min, finally ultrasonically cleaned in deionized water for 20 min, and then placed in a drying box for drying at 50℃ for 1 h to obtain a clean SiC f / Ti3Al composite fastener. The clean SiC fThe / Ti3Al composite fastener is fixed on the sample holder in the middle of the coating chamber. Five 10mm x 75mm x 8mm rectangular small targets of ZrB2, NbSi2, MoSi2, WSi2, and ZrSi2 are placed one by one from top to bottom, and five small targets are taken as a group, and a total of three groups are repeated, and fifteen small targets are spliced into a large composite target, as shown in Figure 1 FIG. 1, which is to avoid uneven element content sputtered by the same target material at different positions of the sample holder. Then the composite target is installed on the target position, and the target standoff is adjusted to 10 cm.

[0051] The coating chamber is vacuumed, and when the vacuum degree reaches 4 x 10 -4 Pa, the gas valve is opened to introduce argon. The gas flow is set to 60 sccm, and the pressure in the coating chamber is adjusted to 0.8 Pa. The sample holder is rotated while the main shaft is revolved, as shown in Figure 2 FIG. 2, the sample rotation switch is turned on, the sample holder rotation speed is set to 5 r / min, the main shaft revolution speed is set to 2 r / min, the ion source switch is turned on, the argon flow is adjusted to control the voltage at 800 V, and the cleaning is performed for 20 min. After cleaning, the argon flow is adjusted to 60 sccm, the ion source switch is turned off, the gas valve is closed, and the gas is turned off. The heating switch is turned on, and the substrate temperature is raised to 400℃. After the vacuum degree in the coating chamber reaches 4 x 10 -4 Pa, the gas valve is opened to introduce argon, the gas flow is 60 sccm, and the pressure in the coating chamber is adjusted to 0.8 Pa. The bias voltage is set to -100 V, the direct current power is turned on for sputtering, the sputtering voltage is adjusted to 475 V, the sputtering current is 738 mA, and the sputtering time is 1 h. After deposition, the direct current power and the bias voltage are turned off, the gas is turned off, the gate valve is adjusted to the maximum, and after the coating chamber is cooled to room temperature, the SiC f / Ti3Al composite fastener with an oxidation-resistant coating is obtained.

[0052] Example 2

[0053] The SiC f / Ti3Al composite fastener is immersed in a hydrofluoric acid solution for 0.5 min, taken out, wiped dry, and placed in an acetone solution, cleaned in an ultrasonic cleaner for 25 min, ultrasonically cleaned in anhydrous ethanol solution for 25 min, and finally ultrasonically cleaned in deionized water for 20 min. Then the SiC f / Ti3Al composite fastener is obtained. The cleaned SiC fThe / Ti3Al composite fastener is fixed on the sample holder in the middle of the coating chamber. Five 10mm x 75mm x 8mm rectangular small targets of ZrB2, NbSi2, MoSi2, WSi2 and SiB6 are placed one by one from top to bottom, and the five small targets form a group, and a total of three groups are repeated, and fifteen small targets are spliced into a large composite target, as shown in Figure 1 The purpose is to avoid uneven element content of the same target material sputtered at different positions of the sample holder. Then the composite target is installed on the target position, and the target standoff is adjusted to 10 cm.

[0054] The coating chamber is evacuated, and when the vacuum degree reaches 4 x 10 -4 Pa, the gas valve is opened and argon is introduced. The gas flow is set to 60 sccm, and the coating chamber pressure is adjusted to 0.8 Pa. The sample holder can rotate while the main shaft revolves, as shown in Figure 2 The sample rotation switch is turned on, the sample holder rotation speed is set to 5 r / min, and the main shaft revolution speed is set to 2 r / min. The ion source switch is turned on, the argon flow is adjusted to control the voltage at 800 V, and the cleaning is performed for 20 min. After cleaning, the argon flow is adjusted to 60 sccm, the ion source switch is turned off, the gas valve is closed, and the gas is turned off. The heating switch is turned on, and the substrate temperature is raised to 400℃. After the vacuum degree in the coating chamber reaches 4 x 10 -4 Pa, the gas valve is opened and argon is introduced, the gas flow is 60 sccm, and the coating chamber pressure is adjusted to 0.8 Pa. The bias voltage is set to -100 V, the direct current power is turned on for sputtering, the sputtering voltage is adjusted to 475 V, the sputtering current is 738 mA, and the sputtering time is 1 h. After deposition, the direct current power and bias voltage are turned off, the gas is turned off, the gate valve is adjusted to the maximum, and after the coating chamber cools down to room temperature, the / Ti3Al composite fastener with an oxidation-resistant coating is obtained. f

[0055] Comparative Example 1

[0056] The Ti3Al sheet is polished on a polishing machine using 1000 mesh, 2000 mesh, 5000 mesh and 6000 mesh sandpaper in sequence until the surface is smooth and free of obvious scratches. Then the polished Ti3Al sheet is immersed in hydrofluoric acid solution for 0.5 min, taken out and dried, placed in acetone solution, cleaned in an ultrasonic cleaner for 25 min, ultrasonic cleaned in anhydrous ethanol solution for 25 min, and finally ultrasonic cleaned in deionized water for 20 min. Then it is placed in a drying oven at 50℃ for 1 h to obtain a clean Ti3Al sheet.

[0057] Comparative Example 2

[0058] The SiC f ​ / Ti3Al composite fastener was immersed in hydrofluoric acid solution for 0.5 min, taken out and wiped dry, and then placed in an acetone solution, cleaned in an ultrasonic cleaner for 25 min, ultrasonically cleaned in anhydrous ethanol solution for 25 min, and finally ultrasonically cleaned in deionized water for 20 min. The cleaned SiC f / Ti3Al composite fastener was immersed in hydrofluoric acid solution for 0.5 min, taken out and wiped dry, and then placed in an acetone solution, cleaned in an ultrasonic cleaner for 25 min, ultrasonically cleaned in anhydrous ethanol solution for 25 min, and finally ultrasonically cleaned in deionized water for 20 min. The cleaned SiC f The / Ti3Al composite fastener was fixed on the sample holder in the middle of the coating chamber. Five small rectangular targets of ZrSi2, NbSi2, MoSi2, WSi2, and ZrSi2 were placed one by one from top to bottom, and the five small targets formed a group. A total of three groups were repeated, and fifteen small targets were spliced into a large composite target, as shown in Figure 1 The purpose of this was to avoid uneven element content sputtered from the same target material at different positions on the sample holder. Then the composite target was installed on the target position, and the target standoff was adjusted to 10 cm.

[0059] The coating chamber was evacuated until the vacuum degree reached 4×10 -4 Pa. The gas inlet valve was opened to introduce argon. The gas flow was set to 60 sccm, and the pressure in the coating chamber was adjusted to 0.8 Pa. The sample holder was rotated while the main shaft was revolved, as shown in Figure 2 The sample rotation switch was turned on, the sample holder rotation speed was set to 5 r / min, and the main shaft revolution speed was set to 2 r / min. The ion source switch was turned on, the argon flow was adjusted to control the voltage at 800 V, and the cleaning was performed for 20 min. After cleaning, the argon flow was adjusted to 60 sccm, the ion source switch was turned off, the gas inlet valve was closed, and the gas was turned off. The heating switch was turned on, and the substrate temperature was raised to 400℃. After the vacuum degree in the coating chamber reached 4×10 -4 Pa, the gas inlet valve was opened to introduce argon, the gas flow was set to 60 sccm, and the pressure in the coating chamber was adjusted to 0.8 Pa. The bias voltage was set to -100 V, the direct current power was turned on for sputtering, the sputtering voltage was adjusted to 475 V, the sputtering current was 738 mA, and the sputtering time was 1 h. After deposition, the direct current power and the bias voltage were turned off, the gas was turned off, the gate valve was adjusted to the maximum, and the sample was taken out after the coating chamber cooled to room temperature, obtaining the SiC f / Ti3Al composite fastener.

[0060] Test Example 1

[0061] The / Ti3Al composite fastener was immersed in hydrofluoric acid solution for 0.5 min, taken out and wiped dry, and then placed in an acetone solution, cleaned in an ultrasonic cleaner for 25 min, ultrasonically cleaned in anhydrous ethanol solution for 25 min, and finally ultrasonically cleaned in deionized water for 20 min. The cleaned SiC f / Ti3Al composite fastener, the Ti3Al sheet sample obtained in Comparative Example 1, and the SiC f / Ti3Al composite fastener samples were subjected to high temperature oxidation tests. The specific steps are as follows: Place the sample in a quartz crucible and place it in the middle of a tube furnace to heat it evenly. Seal the tube furnace port, close the vent valve, turn on the mechanical pump, set the tube furnace heating program, and heat it to 800°C at a rate of 10°C / min. Then turn off the mechanical pump and open the vent valve. Keep warm at 800°C for 4 hours and then turn off the tube furnace switch. Allow the sample to cool naturally to room temperature in the tube furnace, and then take out the sample for SEM characterization and analysis. See the SEM images of the sample cross section and surface. Figures 3-4 , wherein a corresponds to corresponding example 1, b corresponds to corresponding example 2, c corresponds to embodiment 1, and d corresponds to embodiment 2.

[0062] Depend on Figures 3-4 It can be seen that an oxide layer with a thickness of 3.5 μm is formed on the surface of the Ti3Al sample obtained in Comparative Example 1, and a large amount of non-protective metal oxides exists in the oxide layer. There are also many cracks and pores on the surface of the sample, indicating that the Ti3Al sample has undergone severe oxidation at high temperature.

[0063] The thickness of the oxide layer formed on the surface of the high-entropy silicide coating obtained in Comparative Example 2 is 117 nm, which is significantly lower than that of Comparative Example 1. During high-temperature oxidation, Si atoms in the high-entropy silicide coating are preferentially oxidized, forming a SiO2 oxide layer on the coating surface, which hinders the diffusion of oxygen into the coating. This preferential oxidation reduces the formation of non-protective metal oxides and improves the density and integrity of the oxide layer. However, the SEM image of the surface shows that there is still a certain amount of metal oxide on the coating surface, and there are pores between these oxides, which can provide channels for the diffusion of oxygen atoms.

[0064] The high-entropy borosilicate coating obtained in Example 1 has a relatively low boron content, and the thickness of the oxide layer after oxidation is 92 nm. Compared with Comparative Example 2, the oxide layer thickness is further reduced, and the metal oxide on the surface is less, and the oxide layer is more dense. This shows that the introduction of a small amount of boron can improve the oxidation resistance of the high-entropy silicide coating.

[0065] The high-entropy borosilicate coating obtained in Example 2 has a higher boron content than that in Example 1, and the oxide layer thickness after oxidation is 55 nm, which is the lowest oxide layer thickness and the least metal oxide on the surface compared to other comparative examples and examples. The boron element's high-temperature oxidation product, B2O3, combines with SiO2 glass to form a borosilicate (SiO2·B2O3) glass phase, which has low viscosity and high fluidity. This not only allows for the faster formation of a continuous, dense oxide layer on the coating surface, but also repairs cracks and holes formed on the coating surface during the high-temperature oxidation process.

[0066] Test Example 2

[0067] SiC of the deposited oxidation resistant coating obtained from Example 1-2 f SiC of the deposited high-entropy silicide coating obtained from Comparative Example 2 and the / Ti3Al composite fastener sample f The / Ti3Al composite fastener sample was subjected to indentation test and SEM characterization analysis. The SEM images of the sample are shown in Figure 5 , wherein a corresponds to Comparative Example 2, b corresponds to Example 1, and c corresponds to Example 2.

[0068] It can be seen from Figure 5 that the Comparative Example 1 coating surface indentation site has relatively obvious radial cracks, indicating that the toughness of the high-entropy silicide coating is general; the coating surface indentation site obtained from Example 1 and Example 2 has almost no cracks, indicating that the introduction of B element improves the toughness of the high-entropy silicide coating.

[0069] Although the above examples have made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. A method for preparing high entropy silicon boride, characterized in that: The following steps are involved: In an argon environment, a composite target is deposited on a substrate surface by magnetron sputtering to obtain the high entropy silicon boride; the material of the composite target includes MoSi2, WSi2 and NbSi2, and also includes two or more of ZrSi2, ZrB2 and SiB6; The composite target is composed of 3 to 5 groups of target materials; each group of target materials independently includes 5 to 6 small target materials; each group of target materials independently includes MoSi2 target, WSi2 target and NbSi2 target, and also includes two or more of ZrSi2 target, ZrB2 target and SiB6 target; The magnetron sputtering conditions include: an operating pressure of 0.6 Pa to 1.2 Pa, a bias voltage of -50 to -150 V, 2 to 4 target positions, and a distance between the substrate and the composite target of 8 to 12 cm; the magnetron sputtering uses a DC power supply, a sputtering voltage of 200 to 500 V, and a sputtering current of 0.6 to 2 A; The temperature of the substrate is 350-650° C. The high entropy silicon boride includes metal elements and non-metal elements; the metal elements include Zr, Nb, Mo and W; the non-metal elements include Si and B; The molar ratio of the metal element to the non-metal element is 1:1.5-2; The molar ratio of Zr, Nb, Mo and W is 5-40:5-40:5-40:5-40:5-40; The atomic content of B in the non-metallic elements is 5 to 25 at.%.

2. A SiC f / Ti3Al composite fastener, characterized in that: Including SiC f / Ti3Al composite fastener substrate and deposited on the SiC f / Ti3Al composite fastener substrate surface anti-oxidation coating; the material of the anti-oxidation coating is the high entropy silicon boride obtained by the preparation method of claim 1.

3. SiC according to claim 2 f / Ti3Al composite fastener, characterized in that: The thickness of the anti-oxidation coating is 2 to 5 μm.

4. The high entropy silicon boride obtained by the preparation method according to claim 1 or the SiC according to claim 2 or 3 f Application of Ti3Al composite fasteners in aerospace materials.

Images