Corrosion-resistant material and preparation method and application thereof

Abstract

The present application relates to a corrosion-resistant material and its preparation method and application. Among them, the preparation method of the corrosion-resistant material comprises: in a protective gas atmosphere, using plasma spraying, spraying NbMoTaW-based refractory high entropy alloy powder on the surface of the substrate to prepare a coating; the temperature of the substrate is 180°C to 200°C; the spraying distance of the plasma spraying is 80mm to 100mm, the spraying voltage is 78V to 80V, and the spraying current is 500A to 550A. Under the above-mentioned spraying parameters, the flying speed and temperature distribution of the high entropy alloy particles are relatively uniform, and the temperature of the flying particles is relatively high, ensuring the full melting of the high entropy alloy powder. During the spraying process, the temperature and flying speed of the flying particles are relatively high, which ensures that the particles hit the surface of the substrate at a high speed in a molten or semi-molten state, and evenly spread, cool and solidify on the surface of the substrate, stacking layer by layer, and then forming a refractory high entropy alloy coating with a thicker thickness and better corrosion resistance, so as to obtain a corrosion-resistant material with better corrosion resistance.

Description

Technical Field

[0001] The present application relates to the technical field of high entropy alloys, and in particular to a corrosion-resistant material and a preparation method and application thereof. Background Art

[0002] High entropy alloy coating is a new type of multi-principal alloy coating material developed on the basis of high entropy alloy. In the field of high entropy alloy, refractory high entropy alloys formed by refractory metals such as Nb, Mo, Ta and other elements have attracted extensive attention due to their excellent high-temperature mechanical properties. Refractory high entropy alloy coatings have high strength, high hardness, high wear resistance and radiation resistance. The above excellent properties make refractory high entropy alloy coatings have great application potential in aerospace, nuclear fusion reactors and other fields. At present, the preparation methods of refractory high entropy alloy coatings mainly include magnetron sputtering, laser cladding and thermal spraying.

[0003] The coating prepared by the traditional preparation method of refractory high entropy alloy coating is thin and has poor corrosion resistance, which limits its application as a cladding material for high-pressure vessels. Summary of the invention

[0004] Based on this, it is necessary to provide a corrosion-resistant material and its preparation method and application, wherein the preparation method of the corrosion-resistant material can prepare a corrosion-resistant material with a thicker NbMoTaW-based refractory high-entropy alloy coating, which has good corrosion resistance and can be suitable for cladding materials of high-pressure vessels.

[0005] In a first aspect, the present application provides a method for preparing a corrosion-resistant material, characterized by comprising:

[0006] In a protective gas atmosphere, NbMoTaW-based refractory high entropy alloy powder is sprayed on the surface of a substrate by plasma spraying to prepare a coating; the temperature of the substrate is 180°C to 200°C; the spraying distance of the plasma spraying is 80mm to 100mm, the spraying voltage is 78V to 80V, and the spraying current is 500A to 550A.

[0007] In some embodiments, the plasma spraying is conducted in a direction perpendicular to the surface of the substrate.

[0008] In some embodiments, during the plasma spraying, a powder feeding gas is used to feed the NbMoTaW-based refractory high entropy alloy powder, and the feeding rate of the powder feeding is 45 g / min to 50 g / min.

[0009] In one embodiment, the pressure of the protective gas is 0.4 MPa to 0.5 MPa.

[0010] In some embodiments, the NbMoTaW-based refractory high entropy alloy powder is a spherical powder.

[0011] In one of the embodiments, the particle size distribution of the NbMoTaW-based refractory high entropy alloy powder is 25 μm to 53 μm.

[0012] In one embodiment, the NbMoTaW-based refractory high entropy alloy powder also includes at least one of V and B.

[0013] In one embodiment, the molar masses of Nb, Mo, Ta and W in the NbMoTaW-based refractory high entropy alloy powder are equal.

[0014] In some embodiments, the method further includes: performing surface oxidation layer removal treatment on the substrate before performing the plasma spraying.

[0015] In some embodiments, the method further includes: sandblasting the substrate before performing the plasma spraying.

[0016] In a second aspect, the present application provides a corrosion-resistant material prepared using any of the preparation methods described above, wherein the corrosion-resistant material comprises a substrate and a NbMoTaW-based refractory high-entropy alloy coating, wherein the NbMoTaW-based refractory high-entropy alloy coating is located on the surface of the substrate.

[0017] In some embodiments, the NbMoTaW-based refractory high entropy alloy coating has a thickness of 200 μm to 257 μm.

[0018] In a third aspect, the present application provides a corrosion-resistant material prepared by any of the above-mentioned preparation methods or the use of any of the above-mentioned corrosion-resistant materials as a cladding material for a high-pressure vessel.

[0019] The preparation method of the above-mentioned corrosion-resistant material uses plasma spraying to prepare a NbMoTaW-based refractory high-entropy alloy coating. Under the above-mentioned spraying distance, spraying voltage, spraying current and substrate temperature parameters, the speed and temperature distribution of the high-entropy alloy particles are relatively uniform. Within the range of the spraying distance, spraying voltage and spraying current, the temperature of the flying particles is relatively high, ensuring the full melting of the high-entropy alloy powder. The spraying distance also ensures that the particles maintain a relatively high flying speed when they reach the substrate. During the spraying process, the temperature and flying speed of the flying particles are relatively high, and they can be fully spread, which ensures that the particles hit the substrate surface at a high speed in a molten or semi-molten state. Within the temperature range of the substrate, the particles can be evenly spread, cooled and solidified on the substrate surface, stacked layer by layer, and then formed A refractory high-entropy alloy coating with a thicker thickness and better corrosion resistance is formed to obtain a corrosion-resistant material with better corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is a morphology diagram of the NbMoTaW-based refractory high entropy alloy powder provided in Example 1 of the present application. Figure 1 (a) is a low-magnification powder morphology image. Figure 1 Middle (b) is a high-magnification powder morphology image;

[0021] Figure 2 The surface and cross-sectional morphology of the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 of the present application, Figure 2 (a) is the surface morphology of the coating. Figure 2 (b) is the cross-sectional morphology of the coating;

[0022] Figure 3 X-ray diffraction patterns of the NbMoTaW-based refractory high entropy alloy powder and the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 of the present application;

[0023] Figure 4 A hardness distribution curve of the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 of the present application;

[0024] Figure 5 The cross-sectional morphology and energy spectrum of the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 of the present application after static corrosion in lead-bismuth for 500 hours, Figure 5 (a) to (d) are cross-sectional morphology images at different positions. Figure 5 (e) in the middle is the energy spectrum. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0027] An embodiment of the present application provides a method for preparing a corrosion-resistant material, which is characterized by comprising:

[0028] In a protective gas atmosphere, NbMoTaW-based refractory high entropy alloy powder is sprayed on the surface of a substrate by plasma spraying to prepare a coating; the temperature of the substrate is 180°C to 200°C; the spraying distance of the plasma spraying is 80mm to 100mm, the spraying voltage is 78V to 80V, and the spraying current is 500A to 550A.

[0029] The preparation method of the above-mentioned corrosion-resistant material uses plasma spraying to prepare a NbMoTaW-based refractory high-entropy alloy coating. Under the above-mentioned spraying distance, spraying voltage, spraying current and substrate temperature parameters, the speed and temperature distribution of the high-entropy alloy particles are relatively uniform. Within the range of the spraying distance, spraying voltage and spraying current, the temperature of the flying particles is relatively high, ensuring the full melting of the high-entropy alloy powder. The spraying distance also ensures that the particles maintain a relatively high flying speed when they reach the substrate. During the spraying process, the temperature and flying speed of the flying particles are relatively high, which ensures that the particles hit the substrate surface at a high speed in a molten or semi-molten state. Within the temperature range of the substrate, the particles can be evenly spread, cooled and solidified on the substrate surface, stacked layer by layer, and then form a refractory high-entropy alloy coating with a relatively thick thickness and good corrosion resistance, so as to obtain a corrosion-resistant material with good corrosion resistance.

[0030] Optionally, the spraying distance is 80mm, 82mm, 84mm, 86mm, 88mm, 90mm, 92mm, 94mm, 96mm, 98mm or 100mm. When the spraying distance is too large, the powder's flight distance is too long, resulting in an increase in the time it is oxidized, and the deposition efficiency of the powder will be reduced. When the spraying distance is too small, the spray gun will make the temperature of the substrate surface too high, resulting in an increase in oxides on the contact surface between the substrate surface and the coating, affecting the bonding strength.

[0031] Optionally, the spraying voltage is 78V, 78.2V, 78.4V, 78.6V, 78.8V, 79V, 79.2V, 79.4V, 79.6V, 79.8V or 80V.

[0032] Optionally, the spraying current is 500A, 505A, 510A, 515A, 520A, 525A, 530A, 535A, 540A, 545A or 550A.

[0033] The spraying voltage and spraying current jointly determine the size of the spraying power. Within the range of the spraying voltage and spraying current, the melting state of the powder is better, the deposition efficiency of the powder is higher, the density of the obtained coating is larger, and the mechanical properties are higher. When the spraying voltage and spraying current are too high, the substrate will overheat, resulting in a decrease in the bonding strength between the coating and the substrate, and the coating surface will be severely oxidized, which will affect the mechanical properties of the coating. When the spraying voltage and spraying current are too small, the powder cannot be fully melted, so that it cannot be completely spread when it hits the substrate, resulting in the coating being unable to be tightly bonded inside, and the bonding strength between the coating and the substrate will also be reduced.

[0034] Optionally, the temperature of the substrate is 180°C, 182°C, 184°C, 186°C, 188°C, 190°C, 192°C, 194°C, 196°C, 198°C or 200°C. Due to the different thermal expansion coefficients of the coating and the substrate, when the flying high-temperature powder particles hit the surface of the substrate, the high-temperature powder particles cool rapidly. After spraying, internal stress will be generated when both cool to room temperature. This internal stress has a greater effect on the bonding strength between the coating and the substrate. Within the temperature range of the substrate, the internal stress has little effect on the bonding strength between the coating and the substrate. However, when the substrate temperature is too high, the substrate surface is prone to oxidation, resulting in a lower bonding strength between the coating and the substrate.

[0035] In one embodiment, the temperature of the substrate is controlled by placing the substrate on a warming table.

[0036] In some embodiments, the substrate includes at least one of 316L steel and T91 steel.

[0037] In some embodiments, the spraying direction in plasma spraying is perpendicular to the surface of the substrate. The spraying direction is the discharge direction of the powder. When the spraying direction is perpendicular to the surface of the substrate, the sprayed particles spread more evenly on the surface of the substrate.

[0038] In some embodiments, during plasma spraying, a powder feeding gas is used to feed NbMoTaW-based refractory high entropy alloy powder, and the feeding rate of the powder feeding is 45 g / min to 50 g / min. During the coating deposition process, the powder is fed into the plasma flame flow by the carrier gas to heat it to reach a molten or semi-molten state, and then hits the substrate surface at a certain speed to form a flaky structure, and finally cools to form a coating. The feed rate has a great influence on the speed of the powder in the plasma flame flow. Within the range of this feed rate, the high entropy alloy powder is fully melted, and a thicker coating with higher spraying quality can be obtained. Optionally, the feed rate is 45 g / min, 45.5 g / min, 46 g / min, 46.5 g / min, 47 g / min, 47.5 g / min, 48 g / min, 48.5 g / min, 49 g / min, 49.5 g / min or 50 g / min. When the feed rate is too large, the time the powder spends in the plasma flame is reduced and the melting effect is poor. When the powder with poor melting effect is deposited on the substrate, large particles are easily produced, which in turn affects the subsequent powder deposition quality, resulting in lower bonding strength and larger porosity of the coating.

[0039] In some embodiments, the powder feeding gas includes at least one of nitrogen and a rare gas. Using at least one of nitrogen and a rare gas as the powder feeding gas can prevent the particles from being oxidized during flight to obtain a coating of higher quality. Optionally, the protective gas is nitrogen, helium, neon, argon, krypton or xenon.

[0040] In one embodiment, the air flow pressure of the shielding gas is 0.4 MPa to 0.5 MPa. Within the air flow pressure range of the shielding gas, the high entropy alloy powder is fully melted, and a thicker coating with higher spray quality can be obtained. Optionally, the air flow pressure of the shielding gas is 0.4 MPa, 0.41 MPa, 0.42 MPa, 0.43 MPa, 0.44 MPa, 0.45 MPa, 0.46 MPa, 0.47 MPa, 0.48 MPa, 0.49 MPa or 0.5 MPa

[0041] In some embodiments, the NbMoTaW-based refractory high entropy alloy powder is a spherical powder. During the thermal spraying process, the spherical powder particles can ensure the continuous transportation of the powder. At the same time, the spherical powder is heated evenly, which can improve the quality of the coating.

[0042] In one embodiment, the particle size distribution of the NbMoTaW-based refractory high entropy alloy powder is 25μm to 53μm. Within the particle size range of the NbMoTaW-based refractory high entropy alloy powder, during the thermal spraying process, the continuous delivery of the powder can be guaranteed, and the powder is heated more evenly, thereby improving the quality of the coating. Optionally, the particle size of the NbMoTaW-based refractory high entropy alloy powder is 25μm, 26μm, 28μm, 30μm, 35μm, 34μm, 36μm, 38μm, 40μm, 42μm, 44μm, 46μm, 48μm, 50μm or 53μm. When the particle size of the NbMoTaW-based refractory high entropy alloy powder is too large, the powder cannot obtain a good melting effect in the plasma flame flow, and the powder that is not fully melted cannot be fully spread when deposited on the substrate, so that the subsequent spraying particles collide with the coating and there is a gap between them, thereby generating larger holes. When the particle size of the NbMoTaW-based refractory high entropy alloy powder is too small, the powder with too small particle size will aggregate into powder agglomerates. The agglomerated powder cannot obtain a good melting effect, and it will also lead to the inability to fully spread out during the deposition process, increase the gap between the lamellar structures, and reduce the quality of the coating. At the same time, when the particle size of the NbMoTaW-based refractory high entropy alloy powder is too small, the specific surface area of ​​the powder is larger. When the spraying power is the same, the contact area with the air is larger, and the powder is not fully melted, resulting in a higher porosity of the coating.

[0043] In one embodiment, the NbMoTaW-based refractory high entropy alloy powder is prepared by plasma spheroidizing raw materials including Nb, Mo, Ta and W.

[0044] In one embodiment, NbMoTaW-based refractory high entropy alloy powder is prepared by ball milling, slurry mixing, and plasma spheroidization of raw materials including Nb, Mo, Ta, and W.

[0045] In one embodiment, the NbMoTaW-based refractory high entropy alloy powder further includes at least one of V and B. By adding at least one of V and B to the refractory high entropy alloy powder, NbMoTaWV, NbMoTaWB or NbMoTaWVB refractory high entropy alloy powder can be prepared. After adding V or B, the grains of the refractory high entropy alloy can be refined, and the obtained NbMoTaW-based refractory high entropy alloy coating can have good hardness and wear resistance.

[0046] In one embodiment, the molar masses of Nb, Mo, Ta and W in the NbMoTaW-based refractory high entropy alloy powder are equal.

[0047] In some embodiments, the method further includes: performing a surface deoxidation treatment on the substrate before plasma spraying. Performing a surface deoxidation treatment on the substrate can remove the oxide layer and impurities on the surface of the substrate, so that the refractory high entropy alloy coating has a better adhesion effect during spraying.

[0048] In some embodiments, the method further includes: performing sandblasting on the substrate before plasma spraying. Sandblasting can obtain a rough surface on the surface of the substrate, improve the adhesion between the substrate and the refractory high entropy alloy coating, and achieve a better coating preparation effect.

[0049] Another embodiment of the present application provides a corrosion-resistant material prepared using any of the above-mentioned preparation methods. The corrosion-resistant material includes a substrate and a NbMoTaW-based refractory high-entropy alloy coating, and the NbMoTaW-based refractory high-entropy alloy coating is located on the surface of the substrate.

[0050] In some embodiments, the thickness of the NbMoTaW-based refractory high entropy alloy coating is 200 μm to 257 μm. Optionally, the thickness of the NbMoTaW-based refractory high entropy alloy coating is 210 μm to 246 μm. Further optionally, the thickness of the NbMoTaW-based refractory high entropy alloy coating is 210 μm, 212 μm, 215 μm, 220 μm, 225 μm, 230 μm, 240 μm, 245 μm, 250 μm, 252 μm, 255 μm or 257 μm.

[0051] Another embodiment of the present application provides a corrosion-resistant material prepared by any of the above-mentioned preparation methods or an application of any of the above-mentioned corrosion-resistant materials as a cladding material for a high-pressure vessel.

[0052] The following are specific embodiments

[0053] Example 1

[0054] Preparation of NbMoTaW Refractory High Entropy Alloy Coating

[0055] (1) Preparation of NbMoTaW refractory high entropy alloy powder: Nb, Mo, Ta and W single element raw materials with a purity higher than 99.9% were weighed and mixed according to equimolar mass, and spherical powder with a particle size distribution of 25 μm to 53 μm was prepared by ball milling, slurry mixing and plasma spheroidization.

[0056] (2) Substrate pretreatment: 316L austenitic stainless steel with a size of 100mm×100mm×8mm was used as the substrate material. The substrate was polished with different types of sandpaper (80#, 240#, 400#, 800#, 1000#) to remove the oxide layer on the substrate surface. The substrate after the oxide layer was removed was ultrasonically cleaned in an acetone solution to obtain a clean surface, and the substrate was placed in a blast drying oven for drying. The dried substrate was sandblasted with 16# brown corundum sand, the sandblasting distance was 50mm-70mm, the sandblasting angle was 60°-80°, the sand was fed evenly, and the sandblasting nozzle was swung at a constant speed twice. The moving speed was slowed down when the sandblasting reached the edge of the 316L alloy steel substrate.

[0057] (3) Plasma spraying: The pretreated substrate was fixed on a spray rack and kept warm on a heat preservation table at 200 °C; the spraying distance and the distance between the spray gun and the substrate were adjusted to 100 mm, and the NbMoTaW refractory high entropy alloy powder was placed in the powder feeder. The spraying program was set as follows: the high entropy alloy coating was prepared by atmospheric plasma spraying. The spraying voltage was 80 V, the spraying current was 535 A, the spraying distance was 100 mm, the protective gas was nitrogen, the powder feeding gas was argon, the nitrogen gas flow pressure was 0.48 MPa, the powder feeding amount was 48 g / min, and the spraying angle was that the nozzle was perpendicular to the surface of the substrate.

[0058] The thickness of the NbMoTaW refractory high entropy alloy coating prepared in this embodiment is 246 μm.

[0059] The morphology of the NbMoTaW refractory high entropy alloy powder and the coating in this embodiment was characterized, and the hardness and lead-bismuth corrosion resistance of the coating were tested. The results are as follows:

[0060] Reference Figure 1 , Figure 1 This is a morphology diagram of the NbMoTaW-based refractory high entropy alloy powder provided in Example 1. Figure 1 As shown in (a), the NbMoTaW high entropy alloy powder presents a regular spherical structure and a smooth surface. During the thermal spraying process, the spherical powder particles can ensure that the powder is continuously transported and does not get stuck. At the same time, the spherical powder is heated evenly, which can improve the quality of the coating. Figure 1 As shown in (b), the NbMoTaW high entropy alloy powder presents a distinct spherical structure, with a typical dendrite morphology on the surface and a grain size of less than 2 μm. This difference in surface morphology occurs during the spheroidization process of the powder particles due to the different cooling rates of the components. Larger particles take a long time to completely cool and have a slow cooling rate, which gives the atoms inside the particles more time to diffuse and rearrange. During the solidification process, each grain continuously nucleates and grows, thus forming a crack-tooth morphology.

[0061] Reference Figure 2 , Figure 2 The surface and cross-sectional morphology of the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 are as follows: Figure 2 As shown in (a), the powder particles on the surface of the NbMoTaW high entropy alloy coating all show a flat spreading structure, and no unmelted particles are found on the coating surface, indicating that the NbMoTaW alloy powder particles are fully melted. There are certain visible pores on the surface of the high entropy alloy coating, which is because the flat molten particles are not completely covered, thus forming pores at the layered junction. Figure 2 As shown in (b), the NbMoTaW high entropy alloy coating is thicker than 200 μm and presents a typical thermal spray structure with a lamellar and flaky coating morphology. During the thermal spraying process, fully melted powder particles hit the substrate in the form of droplets and spread completely to form a layered structure. In the subsequent rapid cooling process, the powder particles successively hit the substrate and the first deposited particles, forming a typical thermal spray coating structure, which gradually thickens to form a coating of a certain thickness on the workpiece surface.

[0062] Reference Figure 3 , Figure 3 The X-ray diffraction patterns of the NbMoTaW-based refractory high-entropy alloy powder and the NbMoTaW-based refractory high-entropy alloy coating provided in Example 1 show that the NbMoTaW powder has a single-phase BCC structure, indicating that a solid solution structure is formed during the powder preparation process, but there is a weak diffraction peak of the unmelted Nb element. The NbMoTaW high-entropy alloy coating has a single-phase BCC structure, and there is no diffraction peak of the unmelted Nb element. This is because during the spraying process, the center temperature of the spray gun is high enough, the alloy powder particles are completely melted, the Nb element undergoes solid solution, and the alloying process is completed. And during the coating deposition process, the remelting cooling process provides conditions for the further diffusion of the elements, and the large cooling rate promotes the formation of a single-phase solid solution.

[0063] Reference Figure 4 , Figure 4 The hardness distribution curve of the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 can be divided into three hardness regions by observing the hardness change trend of the NbMoTaW refractory high entropy alloy coating: the coating surface region, the coating main region, and the coating and substrate interface region. The coating hardness change is manifested as the microhardness from the coating surface to the coating main region first increases with depth, remains stable after reaching the coating main region, and then decreases at the interface between the coating and the substrate, and finally stabilizes at the hardness value of the substrate. The maximum hardness of the coating is about 480Hv 0.2 .

[0064] The surface hardness of the coating is significantly lower than the main body hardness of the coating. This is because in the final stage of the spraying process, the heat released by the molten particles at the outer edge when solidifying is relatively low, and the coating surface is less sintered by the heat released by the solidification of the powder particles. Therefore, the surface hardness of the coating is lower than the main body hardness of the coating. In the main body of the coating, the hardness gradually reaches the maximum value. At the interface between the coating and the substrate, due to the high flame temperature and fast movement rate of the spray gun during plasma spraying, the temperature difference between the molten particles and the substrate is large, and the excessive cooling rate causes the molten particles to not have enough time to spread on the substrate surface. The subsequent insufficient contact of the powder particles during the stacking process makes it easier to form pores in the coating, resulting in a lower hardness value at the interface between the coating and the substrate.

[0065] Reference Figure 5 , Figure 5 The cross-sectional morphology and energy spectrum of the NbMoTaW-based refractory high entropy alloy coating provided in Example 1 after static corrosion in lead-bismuth for 500 hours. NbMoTaW generates a continuous oxide layer after 500 hours of static lead-bismuth corrosion. The area where the oxide layer is formed corresponds to Figure 5 (a) to (d), Figure 5 The lower left corner of (a) is a partial enlarged view of the box; it can be seen that the average thickness of the oxide layer is about 16μm, and the boundary between the oxide layer and the substrate is clear. Figure 5 From the energy spectrum data in (e), it can be seen that the main components of the oxide layer include residual lead and bismuth and partially dissolved alloy elements, which are mainly Mo-poor and Nb, Ta and W-rich. This is because when Mo comes into contact with liquid lead and bismuth, the dissolution corrosion process occurs first, forming an oxide layer rich in Nb and Ta. The overall structure of the oxide layer is dense, and no cracks are observed in the oxide layer area.

[0066] Example 2

[0067] Preparation of NbMoTaWV Refractory High Entropy Alloy Coating

[0068] (1) Preparation of NbMoTaWV refractory high entropy alloy powder: Nb, Mo, Ta, W and V single element raw materials with a purity higher than 99.9% were weighed and mixed according to equimolar mass, and spherical powder with a particle size distribution of 25 μm to 53 μm was prepared by ball milling, slurry mixing and plasma spheroidization.

[0069] (2) Substrate pretreatment: 316L austenitic stainless steel with a size of 100mm×100mm×8mm was used as the substrate material. The substrate was polished with different types of sandpaper (80#, 240#, 400#, 800#, 1000#) to remove the oxide layer on the substrate surface. The substrate after the oxide layer was removed was ultrasonically cleaned in an acetone solution to obtain a clean surface, and the substrate was placed in a blast drying oven for drying. The dried substrate was sandblasted with 16# brown corundum sand, the sandblasting distance was 50mm-70mm, the sandblasting angle was 60°-80°, the sand was fed evenly, and the sandblasting nozzle was swung at a constant speed twice. The moving speed was slowed down when the sandblasting reached the edge of the 316L alloy steel substrate.

[0070] (3) Plasma spraying: The pretreated substrate was fixed on a spray rack and kept warm on a heat preservation table at 200 °C; the spraying distance and the distance between the spray gun and the substrate were adjusted to 100 mm, and the NbMoTaWV refractory high entropy alloy powder was placed in the powder feeder. The spraying program was set as follows: the high entropy alloy coating was prepared by atmospheric plasma spraying. The spraying voltage was 80 V, the spraying current was 535 A, the spraying distance was 100 mm, the protective gas was nitrogen, the powder feeding gas was argon, the nitrogen gas flow pressure was 0.48 MPa, the powder feeding amount was 48 g / min, and the spraying angle was that the nozzle was perpendicular to the surface of the substrate.

[0071] The thickness of the NbMoTaWV refractory high entropy alloy coating prepared in this embodiment is about 212 μm, and the hardness of the coating is about 590 Hv 0.2 .

[0072] Example 3

[0073] Preparation of NbMoTaWB Refractory High Entropy Alloy Coating

[0074] (1) Preparation of NbMoTaWB refractory high entropy alloy powder: Nb, Mo, Ta, W and B single element raw materials with a purity higher than 99.9% were weighed and mixed according to equimolar mass, and spherical powder with a particle size distribution of 25 μm to 53 μm was prepared by ball milling, slurry mixing and plasma spheroidization.

[0075] (2) Substrate pretreatment: 316L austenitic stainless steel with a size of 100mm×100mm×8mm was used as the substrate material. The substrate was polished with different types of sandpaper (80#, 240#, 400#, 800#, 1000#) to remove the oxide layer on the substrate surface. The substrate after the oxide layer was removed was ultrasonically cleaned in an acetone solution to obtain a clean surface, and the substrate was placed in a blast drying oven for drying. The dried substrate was sandblasted with 16# brown corundum sand, the sandblasting distance was 50mm-70mm, the sandblasting angle was 60°-80°, the sand was fed evenly, and the sandblasting nozzle was swung at a constant speed twice. The moving speed was slowed down when the sandblasting reached the edge of the 316L alloy steel substrate.

[0076] (3) Plasma spraying: The pretreated substrate was fixed on a spray rack and kept warm on a heat preservation table at 200 °C; the spraying distance and the distance between the spray gun and the substrate were adjusted to 100 mm, and the NbMoTaWV refractory high entropy alloy powder was placed in the powder feeder. The spraying program was set as follows: the high entropy alloy coating was prepared by atmospheric plasma spraying. The spraying voltage was 78 V, the spraying current was 500 A, the spraying distance was 100 mm, the protective gas was nitrogen, the powder feeding gas was argon, the nitrogen gas flow pressure was 0.48 MPa, the powder feeding amount was 48 g / min, and the spraying angle was that the nozzle was perpendicular to the surface of the substrate.

[0077] The thickness of the NbMoTaWB refractory high entropy alloy coating prepared in this embodiment is about 210 μm, and the hardness of the coating is about 570 Hv 0.2 .

[0078] Comparative Example 1

[0079] The NbMoTaW refractory high entropy alloy coating is prepared by magnetron sputtering. The coating is deposited on a (100) Si substrate by direct current magnetron sputtering. The thickness of the prepared NbMoTaW refractory high entropy alloy coating is 0.1 μm to 2 μm.

[0080] Comparative Example 2

[0081] The NbMoTaW refractory high entropy alloy coating is prepared on a silicon wafer by using a nanoparticle deposition method. The thickness of the prepared NbMoTaW refractory high entropy alloy coating is about 1 μm.

[0082] Comparative Example 3

[0083] The high entropy alloy coating was prepared by magnetron sputtering. The conditions of magnetron sputtering were as follows: deposition temperature was 300°C, base pressure was 2×10 -3 AlCrFeMoTi high entropy alloy coating prepared on F / M steel at 2500 Pa. The thickness of the prepared AlCrFeMoTi high entropy alloy coating is about 4 μm.

[0084] Comparative Example 4

[0085] The Al-Fe coating prepared on 316FR stainless steel by magnetron sputtering has a coating thickness of about 20 μm.

[0086] Comparative Example 5

[0087] The alloy coating was prepared by low-pressure plasma spraying + laser remelting. The thickness of the FeCrAl coating prepared on T91 steel is about 30μm.

[0088] Comparative Example 6

[0089] The AlTiN coating was prepared on the surface of AISI 1045 steel by physical vapor deposition. The thickness of the prepared AlTiN coating was less than 1 μm.

[0090] The processes of Examples 1 to 3 and Comparative Examples 1 to 6, the chemical formulas of the prepared coatings and the thicknesses of the coatings are shown in Table 1 below:

[0091] Table 1

[0092]

[0093]

[0094] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. A method for preparing a corrosion-resistant material, characterized in that: include: In a protective gas atmosphere, plasma spraying is used to spray NbMoTaW-based refractory high entropy alloy powder on the surface of a substrate to prepare a coating; the NbMoTaW-based refractory high entropy alloy powder is a spherical powder; the particle size of the NbMoTaW-based refractory high entropy alloy powder is 25μm-53μm; the temperature of the substrate is 180℃-200℃; the spraying distance of the plasma spraying is 80mm-100mm, the spraying voltage is 78V-80V, and the spraying current is 500A-550A; The corrosion-resistant material comprises a substrate and a NbMoTaW-based refractory high-entropy alloy coating, wherein the NbMoTaW-based refractory high-entropy alloy coating is located on the surface of the substrate; the thickness of the NbMoTaW-based refractory high-entropy alloy coating is 200 μm to 257 μm.

2. The method for preparing the corrosion-resistant material according to claim 1, characterized in that: The spraying direction in the plasma spraying is perpendicular to the surface of the substrate.

3. The method for preparing the corrosion-resistant material according to claim 1, characterized in that: During the plasma spraying, a powder feeding gas is used to feed the NbMoTaW-based refractory high entropy alloy powder, and the feeding rate of the powder feeding is 45 g / min to 50 g / min.

4. The method for preparing the corrosion-resistant material according to claim 1, characterized in that: The pressure of the protective gas is 0.4 MPa to 0.5 MPa.

5. The method for preparing the corrosion-resistant material according to claim 1, characterized in that: The NbMoTaW-based refractory high entropy alloy powder also includes at least one of V and B.

6. The method for preparing the corrosion-resistant material according to claim 1, characterized in that: The molar masses of Nb, Mo, Ta and W in the NbMoTaW-based refractory high entropy alloy powder are equal.

7. The method for preparing the corrosion-resistant material according to any one of claims 1 to 6, characterized in that: Also includes: Before the plasma spraying, the substrate is subjected to a surface treatment to remove an oxidation layer; And / or the substrate is sandblasted before the plasma spraying.

8. A corrosion-resistant material, characterized in that: The corrosion-resistant material is prepared using the preparation method described in any one of claims 1 to 7, wherein the corrosion-resistant material comprises a substrate and a NbMoTaW-based refractory high-entropy alloy coating, and the NbMoTaW-based refractory high-entropy alloy coating is located on the surface of the substrate.

9. The corrosion-resistant material according to claim 8, characterized in that: The thickness of the NbMoTaW-based refractory high entropy alloy coating is 200 μm to 257 μm.

10. Use of the corrosion-resistant material prepared by the preparation method according to any one of claims 1 to 7 or the corrosion-resistant material according to any one of claims 8 to 9 as a cladding material for a high-pressure vessel.

Images