Preparation method and application of TaAl intermetallic compound coating

Abstract

The invention belongs to the technical field of corrosion prevention of coating materials, and discloses preparation and application of a TaAl intermetallic compound coating, and the TaAl intermetallic compound coating comprises the following elements in percentage by mass: 28-31 wt.% of Al and 69-72 wt.% of Ta. Spherical Al powder and Ta powder are used as raw materials, a base body is treated through a cold spraying process, and a cold spraying layer is prepared; the cold spraying TaAl coating can effectively solve the problem that energy is consumed when high-temperature-resistant metal forms a coating, pitting corrosion is effectively prevented in seawater, and finally the purpose of effectively protecting a steel matrix for a long time is achieved.

Description

Technical Field

[0001] The invention belongs to the field of material corrosion protection, and specifically relates to a preparation method and application of a TaAl intermetallic compound coating. Background Art

[0002] As China's economy continues to develop, the demand for various metal materials has risen sharply. According to data from the World Steel Association, China's apparent steel consumption has already reached more than half of the global consumption. However, steel corrosion generally accounts for one-tenth of the total annually, and the corrosion ratio in the ocean will only be more serious. In the process of developing the ocean, humans have built a series of steel buildings, such as offshore drilling platforms, tidal power generation equipment, and submarine pipelines. These steel buildings are extremely susceptible to corrosion in the marine environment, causing economic losses and even safety accidents.

[0003] The corrosion potential of Al coating is more negative than that of iron and it has a passivation effect and is widely used. During the application process, it was found that the passivation film of Al coating is easily destroyed by Cl in seawater. - The coating is damaged and pitting occurs, and once it is scratched, the substrate will be corroded first. In order to inhibit pitting and wear resistance, other metal elements are considered to be added to improve the anode.

[0004] Ta has excellent corrosion resistance but a very high melting point. According to the phase diagram and existing records, metal Ta and Al can generate TaAl3 intermetallic compounds at around 670℃-1500℃, and TaAl3 intermetallic compounds have better corrosion resistance. However, there is little research on TaAl3 intermetallic compound coatings. Since the melting point of Ta is 3000℃, plasma thermal spraying, hot dip plating and other methods that melt the metal and then spray it evenly on the substrate are difficult to meet the requirements and consume a lot of energy. Cold spraying is based on the principle of deformation and does not require melting of metal, which can provide the possibility of preparing Ta metal compound coatings.

[0005] At present, there are many studies on cold spraying in the preparation of Al-Zn and other coatings, but there is no relevant research on how to prepare TaAl intermetallic compound coatings. The technical problems faced by different alloys are different. For example, CN202111454299.4 cold-sprayed Al-Zn coating was annealed at 200℃≤T<350℃. When the temperature exceeds 350 degrees Celsius, the scanning electron microscope morphology of the coating surface will become a white-gray Zn-Al solid solution. Ta is extremely hard, and the use of cold spraying to prepare pure Ta coatings will rebound after hitting the steel plate, and the coating cannot be formed. The amount of Al powder added is relatively high, otherwise it is difficult to form a Ta-Al coating.

[0006] Therefore, how to prepare TaAl intermetallic compounds with high hardness and corrosion resistance by cold spraying technology is the technical problem to be solved by the present invention. Summary of the invention

[0007] In order to solve the problems existing in the background technology, the present invention provides a method for preparing a TaAl intermetallic compound coating. The TaAl intermetallic compound coating prepared by cold spraying can effectively solve the problem of energy consumption in forming a coating of high temperature resistant metals, and effectively prevent pitting corrosion in seawater, ultimately achieving the purpose of effectively protecting the steel substrate for a long time.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] A method for preparing TaAl intermetallic compound coating

[0010] Using spherical Al powder and Ta powder as raw materials, a substrate is treated by cold spraying process to obtain a cold spray coating; after annealing, a cold spray TaAl coating is obtained;

[0011] Wherein, in terms of raw material mass percentage, the Al is 28-31wt.%, and the Ta is 69-72wt.%;

[0012] The TaAl coating has relatively high requirements for the amount of Al powder added. Only under the above dosage can the preparation of the TaAl coating be guaranteed. If Al is lower or higher than this range, it will be difficult to deposit into a coating or difficult to react completely.

[0013] As a preferred embodiment of the preparation method described in the present invention, the cold spraying process parameters are as follows: the powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2 MPa, the powder feeding temperature is 400-500°C, the powder feeding amount is 80-120 g / min, the distance between the spray gun and the substrate is 10-12 mm, and the spray gun moving speed is 5-8 mm / s.

[0014] As a preferred embodiment of the preparation method of the present invention, the substrate is treated by:

[0015] Build an XY automation platform and check the operation of the spray robot to see if there is any shaking or jamming;

[0016] The base steel was pretreated and grease was removed by ultrasonic cleaning with acetone;

[0017] Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate.

[0018] As a preferred embodiment of the preparation method of the present invention, the annealing temperature is 600°C to 800°C, and the annealing time is 7 to 9 hours. Further preferably, the annealing temperature is 600°C and the annealing time is 8 hours. If the annealing time is too long, the coating will fall off due to the different expansion coefficients of the substrate. Annealing for less than 7 hours will result in insufficient diffusion time, and Al cannot diffuse into Ta. Finally, the preferred annealing temperature is 600°C and the annealing time is 8 hours to ensure diffusion between atoms and effectively prevent Al elements from overflowing.

[0019] Another object of the present invention is to overcome the deficiencies in the prior art and provide a cold sprayed TaAl intermetallic compound coating.

[0020] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a cold sprayed TaAl intermetallic compound coating as an anti-corrosion coating.

[0021] Beneficial effects of the present invention:

[0022] (1) The cold spraying technology used in the present invention has a low working temperature when preparing the coating, which effectively inhibits the adverse effects such as oxidation, phase change, and grain growth.

[0023] (2) The Ta element in the present invention is a coating formed by deformation mechanical biting, which does not require a melting step, saving energy. In addition, the diffusion annealing temperature used in the present invention is lower than the melting point of Al, which can maintain the integrity and density of the coating to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing 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 creative labor. Among them:

[0025] Figure 1 Surface and cross section of the cold sprayed TaAl coating in Example 1 after annealing at 600°C for 8h. In the BES diagram of the coating surface and cross section, a and b are the annealed TaAl surface and annealed TaAl cross section respectively.

[0026] Figure 2 The SEI diagram of the corrosion products removed after the annealed TaAl coating and the pure Al coating in Example 1 and Comparative Example 1 were subjected to a salt spray test in a 5% NaCl solution for 720 hours, wherein a is the Al corrosion morphology of Comparative Example 1 and b is the annealed TaAl corrosion morphology of Example 1.

[0027] Figure 3The electrochemical test results of the TaAl annealed coatings in the comparative examples and embodiments of the present invention after being immersed in a 3.5% NaCl solution for 720 hours.

[0028] Figure 4 The porosity test results of TaAl coatings at different annealing temperatures in the comparative examples and embodiments of the present invention are shown.

[0029] Figure 5 The cross-sectional morphologies of TaAl coatings with different compositions in Comparative Examples 3 and 4 of the present invention, wherein a and b are Ta-40Al cross-sectional and Ta-20Al cross-sectional, respectively.

[0030] Figure 6 The cross-section and surface morphologies of TaAl coatings under different annealing conditions in Comparative Examples 5 and 6 of the present invention, wherein a is the cross-section annealed at 500°C for 8h, and b is the surface annealed at 600°C for 12h. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0034] The XY automation platform in the embodiment of the present invention is provided by Guangzhou Diens Company, and includes an X-axis mechanical arm that moves left and right and a Y-axis mechanical arm that moves forward and backward, and can control the moving distance and moving speed more accurately.

[0035] Example 1

[0036] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0037] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0038] S3: Use white corundum (sandblasting corundum is 100 mesh white corundum provided by Beijing Tianchengyu Company) for sandblasting to remove rust and increase the surface roughness of the substrate;

[0039] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0040] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray composite coating;

[0041] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0042] S7: After vacuum packaging, the TaAl coating is annealed at 600° C. for 8 h to obtain an annealed TaAl coating, i.e., a TaAl3 coating.

[0043] S8: Solder the wires using a solder gun and encapsulate with resin to expose only the test surface.

[0044] S9: The encapsulated samples were immersed in a 3.5% NaCl solution for 720 h and electrochemical tests were performed.

[0045] S10: Two batches of samples were encapsulated using hot mounting powder, and only the test surface was exposed to a neutral salt spray test using a 5% NaCl solution.

[0046] Hardness test was performed using a microhardness tester.

[0047] Figure 1 This is a scanning electron microscope image of the TaAl coating annealed at 600℃ for 8h. It can be seen that the coating reaction is relatively complete, there is almost no elemental Al, and there are no ablation holes in the coating.

[0048] Example 2

[0049] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0050] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0051] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0052] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0053] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray composite coating;

[0054] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0055] S7: After vacuum packaging, the TaAl coating is annealed at 700° C. for 8 h to obtain an annealed TaAl coating, namely, a TaAl3 coating.

[0056] S8: Solder the wires using a solder gun and encapsulate with resin to expose only the test surface.

[0057] S9: The encapsulated samples were immersed in a 3.5% NaCl solution for 720 h and electrochemical tests were performed.

[0058] S10: Two batches of samples were encapsulated using hot mounting powder, and only the test surface was exposed to a neutral salt spray test using a 5% NaCl solution.

[0059] Hardness test was performed using a microhardness tester.

[0060] Example 3

[0061] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0062] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0063] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0064] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0065] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray composite coating;

[0066] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0067] S7: After vacuum packaging, the TaAl coating is annealed at 800° C. for 8 h to obtain an annealed TaAl coating, namely, a TaAl3 coating.

[0068] S8: Solder the wires using a solder gun and encapsulate with resin to expose only the test surface.

[0069] S9: The encapsulated samples were immersed in a 3.5% NaCl solution for 720 h and electrochemical tests were performed.

[0070] S10: Two batches of samples were encapsulated using hot mounting powder, and only the test surface was exposed to a neutral salt spray test using a 5% NaCl solution.

[0071] Hardness test was performed using a microhardness tester.

[0072] Example 4

[0073] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0074] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0075] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0076] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0077] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray composite coating;

[0078] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0079] S7: After vacuum packaging, the TaAl coating is annealed at 900° C. for 8 h to obtain an annealed TaAl coating, namely, a TaAl3 coating.

[0080] S8: Solder the wires using a solder gun and encapsulate with resin to expose only the test surface.

[0081] S9: The encapsulated samples were immersed in a 3.5% NaCl solution for 720 h and electrochemical tests were performed.

[0082] S10: Two batches of samples were encapsulated using hot mounting powder, and only the test surface was exposed to a neutral salt spray test using a 5% NaCl solution.

[0083] Hardness test was performed using a microhardness tester.

[0084] Comparative Example 1

[0085] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0086] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0087] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0088] S4: Using spherical Al powder as raw material, put the Al powder into a vacuum drying oven and dry it for 2 hours.

[0089] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray coating;

[0090] S6: After shaping treatment and strict inspection and acceptance, a cold-sprayed pure Al coating is obtained.

[0091] S7: Solder the wires using a solder gun and encapsulate with resin to expose only the test surface.

[0092] S8: The encapsulated samples were immersed in a 3.5% NaCl solution for 720 h and electrochemical tests were performed.

[0093] S9: Two batches of samples were encapsulated using hot mounting powder, and only the test surface was exposed to a neutral salt spray test using a 5% NaCl solution.

[0094] Hardness test was performed using a microhardness tester.

[0095] Comparative Example 2

[0096] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0097] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0098] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0099] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0100] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray coating;

[0101] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0102] S7: Solder the wires using a solder gun and encapsulate with resin to expose only the test surface.

[0103] S8: The encapsulated samples were immersed in a 3.5% NaCl solution for 720 h and electrochemical tests were performed.

[0104] S9: Two batches of samples were encapsulated using hot mounting powder, and only the test surface was exposed to a neutral salt spray test using a 5% NaCl solution.

[0105] Hardness test was performed using a microhardness tester.

[0106] Comparative Example 3

[0107] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0108] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0109] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0110] S4: S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 40wt.%, Ta 60wt.%, and then mix them thoroughly and put them into a vacuum drying oven to dry for 2 hours.

[0111] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10mm, and the spray gun moving speed is 5mm / s. This parameter is used to prepare the cold spray coating;

[0112] When the Al addition amount is 40%, the coating deposition effect is very good, but the gray Al element occupies the vast majority in the SEM image. After the later annealing, the coating will inevitably have a large amount of excess Al elements. After long-term immersion, the Al2O3 passivation film formed by the Al element in the coating is - Causes pitting.

[0113] Comparative Example 4

[0114] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0115] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0116] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0117] S4: S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 20wt.%, Ta 80wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0118] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10-12mm, and the spray gun moving speed is 5-8mm / s. This parameter is used to prepare the cold spray coating;

[0119] When the Ta powder reaches 80%wt.%, the Ta in the coating is less because the texture of Ta powder is extremely hard. When the Al powder in the mixed powder is insufficient, the Ta powder is difficult to be fully entrained by the Al powder and deposited into a coating. Most of the Ta powder rebounds and the ratio of coating elements is unbalanced. The actual coating is not much different from Ta-60Al, but the coating will be thinner and will also show pitting after long-term immersion.

[0120] Comparative Example 5

[0121] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0122] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0123] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0124] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0125] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10-12mm, and the spray gun moving speed is 5-8mm / s. This parameter is used to prepare the cold spray composite coating;

[0126] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0127] S7: After vacuum packaging, the TaAl coating is annealed at 500° C. for 8 h to obtain an annealed TaAl coating, namely, a TaAl3 coating.

[0128] When the annealing temperature is lower than 600℃, the atoms move slowly, the Al element diffuses insufficiently, and TaAl3 is generated in part of the coating, but most of it is still Al and Ta. After long-term immersion, the Al2O3 passivation film formed by the Al element in the coating is - Causes pitting.

[0129] Comparative Example 6

[0130] S1: Build an XY automation platform and check the operation of the spraying robot to see if there is any shaking or jamming;

[0131] S2: pre-treat the Q235 steel substrate and use acetone ultrasonic cleaning to remove oil stains;

[0132] S3: Use corundum for sandblasting to remove rust and increase the surface roughness of the substrate;

[0133] S4: Use spherical Al powder and Ta powder as raw materials, with a weight ratio of Al 30wt.%, Ta 70wt.%, and mix well, then put into a vacuum drying oven and dry for 2 hours.

[0134] S5: The powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8-1.2MPa, the powder feeding temperature is 500℃, the powder feeding amount is 100g / min, the distance between the spray gun and the substrate is 10-12mm, and the spray gun moving speed is 5-8mm / s. This parameter is used to prepare the cold spray composite coating;

[0135] S6: After shaping and strict inspection and acceptance, cold sprayed TaAl coating is obtained.

[0136] S7: After vacuum packaging, the TaAl coating is annealed at 600° C. for 12 h to obtain an annealed TaAl coating, namely, a TaAl3 coating.

[0137] In Comparative Example 6, the coating will fall off after long-term annealing, and ablation holes will appear on the coating surface.

[0138] One of the hot-mounted samples of the above embodiment and comparative example was taken out, and the hardness was tested using a microhardness tester. The porosity was calculated using ImageJ software. The results are shown in Tables 1 and Figure 4 shown.

[0139] Table 1

[0140]

[0141] It can be seen that the hardness of cold sprayed TaAl coating decreases with the increase of annealing temperature. When the annealing temperature exceeds 600℃, the porosity increases with the increase of annealing temperature.

[0142] The hot-mounted samples in the examples and comparative examples were placed in a salt spray chamber to conduct a neutral salt spray test.

[0143] Among them, the salt spray test is based on GB / T 2423.17-2008. Specifically, the neutral salt spray test is carried out in a YC-60 salt spray tester. All coating surfaces maintain an angle of 30° with the horizontal plane. The samples are taken out after 480 hours to observe the corrosion morphology. The working temperature of the salt spray box is maintained at 35°C, and the spray solution is 5% NaCl solution with a pH value of 6.5-7.2.

[0144] The results are as follows Figure 2 As shown in Figure 5, longer corrosion time leads to pitting of pure Al, but the TaAl coating annealed at 600℃ is relatively intact.

[0145] The samples immersed in step S8 in the embodiment and the comparative example were subjected to electrochemical impedance test.

[0146] Among them, the electrochemical test was carried out using a Princeton P4000A electrochemical workstation, equipped with a circulating water device, the temperature was controlled at 25±1°C, the corrosive electrolyte was a 3.5% NaCl aqueous solution, and it was carried out under a conventional three-electrode system. The immersion time was 240h, and the potentiodynamic polarization test was performed with a scanning frequency of 5mV / s and a scanning range of ±0.5V vs.SHE.

[0147] The results are shown in Table 2 and Figure 3 As shown, it can be seen that among the embodiments and comparative examples, the coating prepared in Example 1 has the highest self-corrosion potential and the lowest self-corrosion current density, so it has the smallest corrosion tendency, the slowest corrosion rate and the best corrosion resistance.

[0148] Table 2

[0149]

[0150] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing a TaAl intermetallic compound coating, characterized in that: Using Al powder and Ta powder as raw materials, the substrate is treated by cold spraying process to obtain cold sprayed TaAl coating, which is annealed at 600℃~800℃ for 7~9h to obtain TaAl3 coating; Wherein, in terms of raw material mass percentage, the Al is 28-31wt.%, and the Ta is 69-72wt.%.

2. The method for preparing the TaAl intermetallic compound coating according to claim 1, characterized in that: The cold spraying process parameters are as follows: the powder feeding gas is compressed air, the spraying angle is 90°, the gas pressure is 0.8~1.2MPa, the powder feeding temperature is 400~500℃, the powder feeding amount is 80~120g / min, the distance between the spray gun and the substrate is 10~12mm, and the spray gun moving speed is 5~8mm / s.

3. The method for preparing the TaAl intermetallic compound coating according to claim 1, characterized in that: The annealing temperature is 600°C and the annealing time is 8h.

4. The cold-sprayed TaAl intermetallic compound coating prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the cold sprayed TaAl intermetallic compound coating as claimed in claim 4 as an anti-corrosion coating.

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