Inert anode of FeCuNiCrAl-based high-entropy alloy composite ceramic coating as well as preparation method and application of inert anode

Abstract

The invention belongs to the technical field of aluminum electrolysis electrodes, and particularly relates to an inert anode of a FeCuNiCrAl-based high-entropy alloy composite ceramic coating and a preparation method of the inert anode. The inert anode is composed of the metal anode base material and the FeCuNiCrAl high-entropy alloy composite ceramic coating on the surface of the metal anode base material, and under the action of the strengthened coating, the inert anode is excellent in electrical conductivity and corrosion resistance, excellent in high-temperature stability and good in mechanical performance. According to the invention, the problems of high energy consumption and high carbon emission of the traditional carbon anode are solved, and the bottlenecks of the existing inert anode in corrosion resistance, conductivity, obdurability and the like are broken through. The preparation method provided by the invention is convenient to operate, and the prepared composite coating inert anode is excellent in forming quality and excellent in performance. The composite coating inert anode is suitable for a cryolite molten salt system at the temperature of 800-1000 DEG C, carbon-free aluminum electrolysis production can be achieved, the composite coating inert anode is environmentally friendly, and cost reduction and efficiency improvement of the aluminum electrolysis industry are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum electrolysis electrodes, in particular to an inert anode of a FeCuNiCrAl-based high entropy alloy composite ceramic coating and a preparation method thereof, and also to the application of the inert anode in the aluminum electrolysis industry. Background Art

[0002] The aluminum metal industry is the second largest metal industry after steel, and the aluminum electrolysis industry is the core and cornerstone of the aluminum metal industry. As a high-energy consumption and high-carbon emission field, the aluminum electrolysis industry still relies on the traditional Hall-Heroult molten salt electrolysis method for its core production process. In this process, the carbon anode, as the core reaction component, will continue to participate in the electrochemical reaction, resulting in the production of about 1.5 tons of CO2 greenhouse gas and harmful gases for every ton of aluminum produced, which not only aggravates environmental climate change and harms the natural environment, but also causes carbon slag accumulation in the electrolytic cell, seriously affecting the current efficiency. In addition, the accumulated costs caused by the frequent replacement of carbon anodes after service failure have created a huge economic cost burden. With the continuous advancement of my country's carbon neutrality strategy, the development of zero-carbon emission inert anode technology has become a technical problem that needs to be solved urgently.

[0003] The core advantage of inert anodes lies in their electrochemical inertness, which can maintain stability during the electrolysis process, achieve "zero consumption" or "micro consumption" service characteristics, prevent CO2 emissions from the source, and significantly reduce the frequency of anode replacement and energy loss. It has great environmental value, industrial application value and economic value. Current research on inert anodes focuses on alloy anode materials and ceramic anode material systems.

[0004] In the alloy anode material system, high entropy alloys show great potential due to their unique "cocktail effect": the synergistic effect of multiple principal elements can induce the formation of a dense passivation film, achieving a dynamic balance between corrosion rate and conductivity in high-temperature molten salts. However, the preparation cost of high-entropy alloy bulk anode materials is high, and large-sized components are prone to grain boundary corrosion failure due to thermal stress, which seriously restricts the progress of industrial application of high-entropy alloys in the development of inert anodes. In the ceramic anode material system, spinel oxide ceramics (such as NiFe2O4, NiAl2O4, CuAl2O4, CuFe2O4) have low solubility in cryolite melts, good corrosion resistance and electrochemical stability, but poor conductivity, mechanical properties and machinability, which seriously restricts its development prospects.

[0005] The coating preparation method based on laser cladding technology can effectively reduce the production cost of materials, overcome processing problems, extend the service life of materials, and improve the comprehensive performance of materials. It is an advanced manufacturing method, especially its design freedom, material freedom, manufacturing process freedom, and performance optimization efficiency, which makes it have broad application prospects.

[0006] Based on this, an inert anode of FeCuNiCrAl-based high-entropy alloy composite ceramic coating based on laser cladding technology is provided. It is of great significance to make the inert anode have excellent high-temperature stability and good mechanical properties while ensuring good electrical conductivity and corrosion resistance of the composite anode material, so as to make it have relatively excellent service performance of the inert anode. In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] One of the purposes of the present invention is to provide a preparation method for an inert anode of FeCuNiCrAl-based high-entropy alloy composite ceramic coating.

[0008] Another purpose of the present invention is to provide an inert anode of FeCuNiCrAl-based high-entropy alloy composite ceramic coating.

[0009] The third purpose of the present invention is to provide an application of an inert anode of FeCuNiCrAl-based high-entropy alloy composite ceramic coating in the aluminum electrolysis industry.

[0010] The technical solution adopted by the present invention to achieve the first purpose is: to provide a preparation method for an inert anode of FeCuNiCrAl-based high-entropy alloy composite ceramic coating, including the following steps: S1. Prepare and pre-treat the composite high-performance powder; the composite high-performance powder is composed of high-entropy alloy powder and ceramic powder; the high-entropy alloy powder is FeCuNiCrAl; the ceramic powder is composed of NiFe2O4, NiAl2O4, CuAl2O4, CuFe2O4 and NiO. S2. Under the protection of inert gas, use the laser cladding method to form a high-efficiency composite coating on the surface of the pre-treated metal anode substrate with the composite high-performance powder to obtain a composite anode material. S3. Heat-treat the composite anode material in an inert atmosphere at 800 - 1200 °C for 4 - 6 h, and finally cool it to room temperature at a rate of 3 - 7 °C / min to obtain a composite inert anode.

[0011] The general idea and invention principle of the present invention are as follows: In view of the defects of the existing inert anode technology, the present invention provides an inert anode with good electrical conductivity, corrosion resistance, excellent high-temperature stability and good mechanical properties and its preparation method. The inert anode includes a metal anode substrate and a high-efficiency composite coating with a protective effect on its surface, and the high-efficiency composite coating is a FeCuNiCrAl high-entropy alloy composite ceramic coating.

[0012] In terms of the selection of coating raw materials and components, in the present invention, a composite high-performance powder composed of high-entropy alloy powder and ceramic powder is formed on the surface of a metal anode substrate by laser cladding to obtain a high-performance composite coating. Among them, the Cu element in the FeCuNiCrAl high-entropy alloy can improve the electrical conductivity of the material, relieve the thermal stress of the material, enhance the thermal shock resistance, and at the same time optimize the forming process of the electrode; the Ni element can improve the antioxidant ability and high-temperature stability; the Cr and Al elements can enhance the corrosion resistance and antioxidant ability of the anode material. The FeCuNiCrAl high-entropy alloy and the formed oxide film have good electrical conductivity and mechanical properties, ensuring the service effect of the inert anode. Further, the metal elements contained in NiFe2O4, NiAl2O4, CuAl2O4, and CuFe2O4 in the ceramic powder are the same as those in the high-entropy alloy, and will not pollute the high-entropy alloy system, ensuring the full play of the advantages of the high-entropy effect and cocktail effect of the high-entropy alloy. The above-mentioned ceramic phase with a spinel structure can enhance the corrosion resistance of the aluminum electrolysis anode to high-temperature molten salt electrolyte, effectively prevent the continuous erosion of the anode by the electrolyte melt, improve the mechanical properties and thermal shock resistance of the anode material, and improve the high-temperature stability of the anode material; in addition, the addition of NiO can improve the mechanical strength and thermal stability of the composite anode material, and cooperate with the spinel structure ceramic to improve the electrical conductivity and corrosion resistance of the material.

[0013] In terms of the preparation method, through research, it is found that in the conventional preparation process and post-treatment process, it is difficult to avoid the partial precipitation and agglomeration tendency of the ceramic phase in the high-entropy alloy matrix, and the precipitation and agglomeration of the ceramic phase will lead to uneven composition and structure of the inert anode, which will have a negative impact on the service effect and cause unstable performance of the inert anode. For the above reasons, in addition to using the laser cladding process to form the coating, the preparation method of the present invention also uses a unique post-treatment process, specifically heat treatment in an inert atmosphere at 800-1200 °C for 4-6 h, and then slowly cooling to room temperature. This post-treatment process enables the ceramic phase to be fully dissolved in the high-entropy alloy matrix, preventing the aggregation and precipitation of the ceramic phase, making the obtained coating have uniform contrast and good microstructure consistency, thereby improving the comprehensive performance of the coating.

[0014] Furthermore, in the present invention, an inert anode system mainly composed of FeCuNiCrAl high-entropy alloy and supplemented by ceramic phase is constructed relying on the characteristics of high-entropy alloy. Among them, the high-entropy alloy is the main component of the coating system and the core guarantee for the performance of the inert anode, ensuring that the inert anode has good mechanical properties, good electrical conductivity and acceptable corrosion resistance in high-temperature molten salt; the ceramic phase belongs to the strengthening component in the coating system, and the addition of the ceramic phase can reduce the production cost of the inert anode, improve the corrosion resistance and electrochemical stability of the anode. However, an excessive amount of ceramic phase will cause a rapid decrease in the electrical conductivity of the inert anode and affect the processing performance, manifested as easy cracking of the coating. Therefore, it is necessary to control the content of the ceramic phase in the coating within a suitable range. Preferably, in the composite high-performance powder, the content of the ceramic powder is 18wt.% - 32wt.%. Under this condition, the addition of the ceramic phase can not only enhance the comprehensive performance of the inert anode, but also avoid damaging the advantages of the high-entropy alloy system.

[0015] Preferably, in step S1, the composite high-performance powder is composed of the following components by weight percentage: Fe is 15.7% - 18.3%; Cu is 18.4% - 19.9%; Ni is 16.6% - 18.6%; Cr is 14.0% - 16.0%; Al is 6.0% - 9.2%; NiFe2O4 is 6.5% - 9.5%; NiAl2O4 is 3% - 5%; CuAl2O4 is 5.2% - 7.8%; CuFe2O4 is 3% - 5%; NiO is 1% - 4%.

[0016] Furthermore, in step S1, the particle sizes of the high-entropy alloy powder and the ceramic powder are 50 - 100μm; the pretreatment process includes ball milling and drying.

[0017] Preferably, the rotation speed of the ball milling is 200 - 400 rpm, the ball milling time is 3 - 6h, and the ball-to-material ratio is 4 - 7:1. The drying treatment is vacuum drying of the composite high-performance powder after ball milling, the drying temperature is 60 - 80°C, and the drying time is 6 - 10h.

[0018] Furthermore, in step S2, the pretreatment method of the metal anode substrate includes four stages: the first stage is to polish the metal anode substrate with a angle grinder to remove the surface oxide layer and stains; the second stage is to polish the surface of the anode substrate with 400 - 1600 mesh sandpaper to make it have good surface flatness; the third stage is to clean it with acetone or absolute ethanol; the fourth stage is to dry it in a vacuum environment at 60 - 80°C for 60 - 90min. In the present invention, by pretreating the metal anode substrate, it can be ensured that during the subsequent laser cladding process, a high-quality metallurgical bond is formed between the composite strengthening coating and the substrate, and the generation of defects such as pores, slag inclusions, and cracks can be avoided as much as possible.

[0019] Further, in step S2, the inert gas is argon, and the gas flow rate for protection and powder feeding is 360 - 480 L / h.

[0020] Further, in step S2, laser cladding is carried out in a synchronous powder feeding manner, and the powder feeding rate is 30 - 60 g / min.

[0021] Further, in step S2, the laser power is 1500 - 2100 W, the scanning speed is 10 - 18 mm / s, the overlapping rate of multi - path cladding is 40% - 60%, and the laser focal length is 6 - 10 mm.

[0022] In the preparation method provided by the present invention, for the composition and proportion of the composite high - performance powder, the process parameters in the above - mentioned laser cladding are selected. The melting points of different components of the FeCuNiCrAl high - entropy alloy powder and the ceramic powder composed of NiFe2O4, NiAl2O4, CuAl2O4, CuFe2O4, and NiO are different. In order to ensure the processing quality of laser cladding, the laser power needs to be selected within a suitable range; at the same time, the inert gas protection and powder feeding gas flow rate, the overlapping rate of multi - path cladding, and the laser focal length within a suitable range can ensure the forming quality of the high - performance strengthening coating; the powder feeding rate and scanning speed within a suitable range can ensure the full combination of the coating and the substrate and avoid resource waste.

[0023] Further, in step S2, the metal anode substrate is selected from substrates with good electrical conductivity, including Q235 alloy steel.

[0024] Further, in step S2, the thickness of the high - energy - efficiency composite coating is 0.6 - 2.4 mm.

[0025] Further, in step S3, the composite anode material is first polished and then heat - treated in an inert atmosphere at 800 - 1200 °C. Preferably, 400 - 2000 - mesh sandpaper is used to polish the composite anode material to reduce its surface roughness; the inert atmosphere used for the heat - treatment is argon.

[0026] Further, in step S3, by placing the composite anode material in an inert atmosphere at 800 - 1200 °C for 4 - 6 h, the micro - defects inside the anode material can be reduced, the complex stress can be released, the homogenization of the material can be improved, and its stability in subsequent use can be enhanced. After heat - treatment, it is slowly cooled at a rate of 3 - 7 °C / min, which can prevent the sudden increase of internal stress in the anode material due to rapid cooling, avoid the generation of cracks and deformation of the material, contribute to the formation of a more stable microstructure, and thus improve its performance as an anode material.

[0027] Another technical solution adopted to achieve the second object of the present invention is: to provide an inert anode of an FeCuNiCrAl-based high-entropy alloy composite ceramic coating, which is prepared by the preparation method described in the first object of the present invention.

[0028] For the inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating prepared in the present invention, the coating uses the high-entropy alloy as the matrix, and the ceramic phases (spinel and NiO) are fully dissolved in the high-entropy alloy matrix, having good microstructure consistency.

[0029] Another technical solution adopted to achieve the third object of the present invention is: to provide an application of the inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating described in the second object of the present invention in the aluminum electrolysis industry.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) For the preparation method of the inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating provided by the present invention, the laser cladding method is adopted to prepare a high-performance composite coating on the surface of the metal anode substrate. The raw materials of the high-performance composite coating are composed of the high-entropy alloy powder FeCuNiCrAl and the ceramic powder containing metal oxides with spinel structure that matches its metal elements. The two cooperate with each other and act synergistically to improve the mechanical strength, thermal stability, electrical conductivity and corrosion resistance of the coating. In addition, the preparation method provided by the present invention also uses a special post-treatment method to fully dissolve the ceramic phase in the high-entropy alloy matrix, prevent the aggregation and precipitation of the ceramic phase, make the prepared coating uniform, have good microstructure consistency, and further ensure the better performance of the comprehensive performance of the coating. The above preparation method is convenient to operate, and the formed quality of the prepared composite coating inert anode is excellent, and the bonding performance is excellent, realizing the cost reduction and efficiency increase of the inert anode preparation technology.

[0031] (2) The inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating prepared in the present invention is composed of a metal anode substrate and a high-performance FeCuNiCrAl high-entropy alloy composite ceramic coating with a protective effect on its surface. It has good electrical conductivity and corrosion resistance, excellent high-temperature stability and good mechanical properties, solves the problems of high energy consumption and high carbon emissions of traditional carbon anodes, and breaks through the technical problems existing in the existing inert anodes in terms of corrosion resistance, electrical conductivity, toughness and other properties.

[0032] (3)The inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating prepared by the present invention. The composite coating not only maintains the unique advantages of the high-entropy alloy system, but also the ceramic phase composed of the same metal elements can be fully dissolved in the high-entropy alloy matrix, thereby improving the microstructure efficiency. The composite coating on the surface of the inert anode prepared by the present invention undergoes a special post-treatment process, and the porosity is not higher than 1.21‰. The average hardness of the coating is 644.2 HV, about 4 times that of the substrate material hardness (165 HV). The coating forms a metallurgical bond with the substrate, and its bonding strength is as high as 537 MPa. The conductivity of the coating is 378 S / cm, and the corrosion current density of the coating is 6.17× 10 -8 A / cm 2 , with excellent comprehensive performance, and has broad promotion and application prospects in the aluminum electrolysis industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is an operation schematic diagram for preparing an FeCuNiCrAl high-entropy alloy composite ceramic coating on the surface of a metal anode substrate by using laser cladding technology provided by an embodiment of the present invention; Figure 2 is a scanning electron microscope image of the bonding region between the FeCuNiCrAl-based high-entropy alloy composite ceramic coating and the metal anode substrate in the inert anode prepared in Example 1 of the present invention; Among them, 1 - Q235 alloy substrate; 2 - high-entropy alloy composite ceramic coating; 3 - fusion line. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0036] An embodiment of the present invention provides a method for preparing an inert anode of an FeCuNiCrAl-based high-entropy alloy composite ceramic coating, including the following steps: Step 1: Prepare and pre-treat the composite high-performance powder; the composite high-performance powder is composed of high-entropy alloy powder and ceramic powder; the high-entropy alloy powder is FeCuNiCrAl; the ceramic powder is composed of NiFe2O4, NiAl2O4, CuAl2O4, CuFe2O4 and NiO; specifically, the composite high-performance powder is composed of the following components by weight percentage: Fe is 15.7%-18.3%; Cu is 18.4%-19.9%; Ni is 16.6%-18.6%; Cr is 14.0%-16.0%; Al is 6.0%-9.2%; NiFe2O4 is 6.5%-9.5%; NiAl2O4 is 3%-5%; CuAl2O4 is 5.2%-7.8%; CuFe2O4 is 3%-5%; NiO is 1%-4%. The particle sizes of the high-entropy alloy powder and the ceramic powder are 50-100 μm; the pre-treatment process includes ball milling treatment and drying treatment.

[0037] Step 2: As Figure 1 shown, under the protection of inert gas, use the laser cladding method to form a high-efficiency composite coating on the surface of the pre-treated metal anode substrate with the composite high-performance powder to obtain a composite anode material; in the laser cladding, the inert gas is argon, and the gas flow rate in protection and powder feeding is 360-480 L / h; the laser cladding is carried out by the synchronous powder feeding method, and the powder feeding rate is 30-60 g / min; the laser power is 1500-2100 W, the scanning speed is 10-18 mm / s, the overlapping rate of multi-path cladding is 40%-60%, and the laser focal length is 6-10 mm.

[0038] Step 3: Grind the composite anode material, and then heat-treat the composite anode material in an inert atmosphere at 800-1200 °C for 4-6 h, and cool it to room temperature at a rate of 3-7 °C / min to obtain a composite inert anode. The composite inert anode is composed of a metal anode substrate and a high-efficiency composite coating on its surface, and the thickness of the high-efficiency composite coating is 0.6-2.4 mm.

[0039] The present invention will be further described below in conjunction with specific embodiments, but it is not limited to the present invention.

[0040] Example 1 This example provides a preparation method of an inert anode with an FeCuNiCrAl-based high-entropy alloy composite ceramic coating. Among them, the metal anode substrate is Q235 alloy steel, and the preparation method includes the following steps: Step 1: According to the composition ratio of the FeCuNiCrAl high-entropy alloy composite ceramic coating, select raw material powders of 17.0 wt.% Fe, 19.2 wt.% Cu, 17.5 wt.% Ni, 15.0 wt.% Cr, 7.6 wt.% Al, 7.0 wt.% NiFe2O4, 4.0 wt.% NiAl2O4, 6.5 wt.% CuAl2O4, 4.0 wt.% CuFe2O4, and 2.2 wt.% NiO. The average particle size of the powders is 50 - 100 μm. Then, conduct ball milling treatment. Set the ball milling speed at 300 revolutions per minute, the ball milling working duration at 4 h, and the ball-to-material ratio at 5:1. After that, conduct vacuum drying on the ball-milled composite high-performance powder. The drying temperature is 70 °C, and the drying time is 8 h.

[0041] Step 2: Use an angle grinder to polish the Q235 alloy steel substrate until it is clean, removing the surface oxide layer and stains. Subsequently, polish the surface of the Q235 alloy steel substrate with 400, 800, 1200, and 1600 - mesh sandpapers in sequence. After polishing, use acetone to wash and remove the surface residues. Then, dry the Q235 alloy steel substrate in a vacuum environment at 70 °C for 80 min. Start the synchronous powder feeding type laser cladding equipment. Introduce argon gas into the cladding working system as the protective gas and the powder feeding power gas. Set the gas flow rate at 400 L / h, the laser power at 1800 W, the scanning speed at 15 mm / s, the powder feeding rate at 45 g / min, the multi-path cladding overlap rate at 50%, and the laser focal length at 8 mm. Conduct multi-path overlap cladding work on the Q235 alloy steel substrate along the Figure 1 indicated cladding travel direction, so that the selected raw material powders form a cladding coating on the surface of the Q235 alloy steel substrate, obtaining the FeCuNiCrAl high-entropy alloy composite ceramic coating.

[0042] Step 3: Polish the surface of the composite anode material with 400, 800, 1200, 1600, and 2000 - mesh sandpapers in sequence to reduce the surface roughness. Subsequently, place the composite anode material in an argon environment at 1000 °C for 5 h, and finally cool it at a cooling rate of 5 °C / min to return to room temperature, preparing an inert anode with a FeCuNiCrAl-based high-entropy alloy composite ceramic coating. The thickness of the high-efficiency composite coating on the surface of the Q235 alloy steel substrate is 1.2 mm.

[0043] Use a scanning electron microscope (SEM) to observe the bonding area between the Q235 alloy steel substrate and the FeCuNiCrAl-based high-entropy alloy composite ceramic coating in the prepared inert anode, as Figure 2 shown. Figure 2The fusion line in it is smooth and natural, without irregular deformation and sharp fluctuations, indicating that a metallurgical bond with good quality has been formed between the coating and the substrate; Figure 2 No obvious defects such as cracks and pores were observed in it, indicating that the prepared inert anode has good forming quality; Figure 2 No aggregation and precipitation of ceramic phases were observed in it, indicating that the ceramic phases were fully solid-solved with the high-entropy alloy during the laser cladding process. The prepared coating has uniform contrast and good microstructure consistency.

[0044] Compared with the high-performance coating of the inert anode without subsequent heat treatment under the same conditions, in this embodiment, the composite anode material is treated in an argon environment at 1000 °C for 5 h, which can reduce the microdefects inside the material, release complex stresses, improve the homogenization of the material, and improve the strength and toughness of the material. Combining Figure 2 It can be seen that the anode material has good forming quality, without deformation or cracking, no obvious defects were observed, and no aggregation and precipitation of ceramic phases were observed. In addition, after heat treatment, it is slowly cooled to room temperature at a rate of 5 °C / min, which avoids the sudden increase of internal stress in the anode material due to rapid cooling, prevents the generation of cracks and deformation of the material, and is beneficial to improving the stability and consistency of the microstructure. This is consistent with Figure 2 the observation results.

[0045] After comparative testing, the operations of heat treatment and slow cooling after laser cladding reduce the porosity in the coating from 1.84% to 0.21%, achieving a significant decrease. In addition, the average hardness of the coating prepared in this embodiment is 644.2 HV, about 4 times that of the substrate material hardness (165 HV); the coating forms a metallurgical bond with the Q235 alloy steel substrate, and its bonding strength is as high as 537 MPa; the corrosion current density of the coating is 6.17×10 -8 A / cm 2 , and the coating conductivity is 378 S / cm, showing excellent comprehensive performance and better meeting the application requirements in the aluminum electrolysis industry.

[0046] Example 2 This embodiment provides a preparation method for an inert anode of an FeCuNiCrAl-based high-entropy alloy composite ceramic coating. Among them, the metal anode substrate is Q235 alloy steel, and the preparation method includes the following steps: Step 1: According to the composition ratio of the FeCuNiCrAl high-entropy alloy composite ceramic coating, select raw material powders of 15.7 wt. % Fe, 19.9 wt. % Cu, 18.6 wt. % Ni, 14.0 wt. % Cr, 7.5 wt. % Al, 9.5 wt. % NiFe2O4, 3.0 wt. % NiAl2O4, 7.8 wt. % CuAl2O4, 3.0 wt. % CuFe2O4, and 1 wt. % NiO. The average particle size of the powders is 50 - 100 μm. Then, perform ball milling treatment. Set the ball milling speed at 300 revolutions per minute, the ball milling working duration at 4 h, and the ball-to-material ratio at 5:1. After that, conduct vacuum drying on the ball-milled composite high-performance powder. The drying temperature is 70 °C, and the drying time is 8 h.

[0047] Step 2: Use an angle grinder to polish the Q235 alloy steel substrate until it is clean, removing the surface oxide layer and stains. Subsequently, polish the surface of the Q235 alloy steel substrate successively with 400, 800, 1200, and 1600 - mesh sandpapers. After polishing, use acetone to wash and remove the surface residues. Then, dry the Q235 alloy steel substrate in a vacuum environment at 70 °C for 80 min. Start the synchronous powder feeding type laser cladding equipment. Introduce argon gas into the cladding working system as the protective gas and the powder feeding power gas. Set the gas flow rate at 480 L / h, the laser power at 2100 W, the scanning speed at 18 mm / s, the powder feeding rate at 60 g / min, the multi - path cladding overlap rate at 40%, and the laser focal length at 10 mm. Conduct multi - path overlap cladding work on the Q235 alloy steel substrate along Figure 1 the indicated cladding traveling direction shown, so that the selected raw material powders form a cladding coating on the surface of the Q235 alloy steel substrate, obtaining the FeCuNiCrAl high - entropy alloy composite ceramic coating.

[0048] Step 3: Polish the surface of the composite anode material successively with 400 - mesh, 800 - mesh, 1200 - mesh, 1600 - mesh, and 2000 - mesh sandpapers to reduce the surface roughness. Subsequently, place the composite anode material in an argon environment at 1200 °C for 4 h, and finally cool it at a cooling rate of 3 °C / min to return to room temperature, preparing an inert anode of the FeCuNiCrAl - based high - entropy alloy composite ceramic coating. The thickness of the high - efficiency composite coating on the surface of the Q235 alloy steel substrate is 1.5 mm.

[0049] Example 3 This example provides a preparation method for an inert anode of an FeCuNiCrAl - based high - entropy alloy composite ceramic coating. Among them, the metal anode substrate is Q235 alloy steel, and the preparation method includes the following steps: Step 1: According to the composition ratio of the FeCuNiCrAl high-entropy alloy composite ceramic coating, select raw material powders of 18.3 wt.% Fe, 18.4 wt.% Cu, 16.6 wt.% Ni, 15.0 wt.% Cr, 6 wt.% Al, 6.5 wt.% NiFe2O4, 5.0 wt.% NiAl2O4, 5.2 wt.% CuAl2O4, 5.0 wt.% CuFe2O4, and 4 wt.% NiO. The average particle size of the powders is 50 - 100 μm. Then, perform ball milling treatment. Set the ball milling speed at 300 revolutions per minute, the ball milling working duration at 4 h, and the ball-to-powder ratio at 5:1. After that, conduct vacuum drying on the ball-milled composite high-performance powder. The drying temperature is 70°C, and the drying time is 8 h.

[0050] Step 2: Use an angle grinder to polish the Q235 alloy steel substrate clean, removing the surface oxide layer and stains. Subsequently, polish the surface of the Q235 alloy steel substrate with 400, 800, 1200, and 1600-mesh sandpapers in sequence. After polishing, use acetone to wash and remove the surface residues. Then, dry the Q235 alloy steel substrate in a vacuum environment at 70°C for 80 min. Start the synchronous powder feeding laser cladding equipment. Introduce argon gas into the cladding working system as the protective gas and the powder feeding power gas. Set the gas flow rate at 360 L / h, the laser power at 1500 W, the scanning speed at 10 mm / s, the powder feeding rate at 30 g / min, the multi-path cladding overlap rate at 60%, and the laser focal length at 6 mm. Conduct multi-path overlapping cladding work on the Q235 alloy steel substrate along the Figure 1 indicated cladding traveling direction, so that the selected raw material powders form a cladding coating on the surface of the Q235 alloy steel substrate, obtaining the FeCuNiCrAl high-entropy alloy composite ceramic coating.

[0051] Step 3: Polish the surface of the composite anode material with 400-mesh, 800-mesh, 1200-mesh, 1600-mesh, and 2000-mesh sandpapers in sequence to reduce the surface roughness. Subsequently, place the composite anode material in an argon environment at 800°C for 6 h. Finally, cool it at a cooling rate of 7°C / min to return to room temperature, preparing an inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating. The thickness of the high-efficiency composite coating on the surface of the Q235 alloy steel substrate is 1.4 mm.

[0052] The above are only preferred embodiments of the present invention, and thus do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be able to realize that all equivalent replacements and obvious changes made by using the content of the present invention specification should be included within the protection scope of the present invention.

Claims

1. A preparation method of an inert anode of a FeCuNiCrAl-based high-entropy alloy composite ceramic coating, characterized in that, It includes the following steps: S1. Prepare and preprocess the composite high-performance powder; the composite high-performance powder is composed of high-entropy alloy powder and ceramic powder; the high-entropy alloy powder is FeCuNiCrAl; the ceramic powder is composed of NiFe2O4, NiAl2O4, CuAl2O4, CuFe2O4 and NiO; S2. Under the protection of inert gas, use the laser cladding method to form a high-efficiency composite coating on the surface of the preprocessed metal anode substrate to obtain a composite anode material; S3. Heat-treat the composite anode material in an inert atmosphere at 800 - 1200 °C for 4 - 6 h, and finally cool it to room temperature at a rate of 3 - 7 °C / min to obtain a composite inert anode.

2. The preparation method according to claim 1, characterized in that, In step S1, in the composite high-performance powder, the content of the ceramic powder is 18 wt.% - 32 wt.%.

3. The preparation method according to claim 2, characterized in that, In step S1, by weight percentage, the composite high-performance powder is composed of the following components: Fe is 15.7% - 18.3%; Cu is 18.4% - 19.9%; Ni is 16.6% - 18.6%; Cr is 14.0% - 16.0%; Al is 6.0% - 9.2%; NiFe2O4 is 6.5% - 9.5%; NiAl2O4 is 3% - 5%; CuAl2O4 is 5.2% - 7.8%; CuFe2O4 is 3% - 5%; NiO is 1% - 4%.

4. The preparation method according to claim 1, wherein, In step S1, the particle sizes of the high-entropy alloy powder and the ceramic powder are 50 - 100 μm; the preprocessing process includes ball milling treatment and drying treatment.

5. The preparation method according to claim 1, characterized in that, In step S2, the inert gas is argon, and the gas flow rate in protection and powder feeding is 360 - 480 L / h.

6. The preparation method according to claim 1, characterized in that, In step S2, laser cladding is carried out in a synchronous powder feeding mode, and the powder feeding rate is 30 - 60 g / min.

7. The preparation method according to claim 6, characterized in that, In step S2, the laser power is 1500 - 2100 W, the scanning speed is 10 - 18 mm / s, the overlapping rate of multi-path cladding is 40% - 60%, and the laser focal length is 6 - 10 mm.

8. The preparation method according to claim 1, characterized in that, In step S2, the thickness of the high-efficiency composite coating is 0.6 - 2.4 mm.

9. An inert anode of a FeCuNiCrAl-based high-entropy alloy composite ceramic coating, characterized in that, It is prepared by the preparation method according to any one of claims 1 - 8.

10. Application of the inert anode of the FeCuNiCrAl-based high-entropy alloy composite ceramic coating according to claim 9 in the aluminum electrolysis industry.

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