An erosion-resistant coating for a lead-based reactor pump impeller and a method of making the same

Abstract

The application discloses an anti-erosion coating for a lead-based reactor pump impeller and a preparation method thereof. The coating has a double-layer structure, the inner layer is an FeCrNbMoTiAlY high-entropy alloy coating with chemical components and a thermal expansion coefficient matched with a metal base, and the outer layer is a TiAlSiN metal ceramic coating. The preparation method comprises the following steps: proportionally performing magnetic suspension smelting on iron, chromium, niobium, molybdenum, titanium, aluminum and yttrium, then performing hot isostatic pressing to prepare a high-entropy alloy target material, proportionally mixing titanium, aluminum and silicon powder to perform hot isostatic pressing to prepare a TiAlSi target material, and then sequentially adopting a magnetron sputtering method to prepare a high-entropy alloy coating and a metal ceramic coating on the surface of the metal base. The double-layer structure coating can relieve thermal stress between the coating and the metal base, improve the bonding force between the coating and the base, the inner layer also has good corrosion resistance, the outer coating has excellent wear resistance and corrosion resistance, and the ability of the coating to resist high-flow-speed lead alloy scouring corrosion is comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, and in particular to an anti-erosion coating for lead-based reactor pump impellers and its preparation method. Background Technology

[0002] Lead-based reactors, using liquid lead alloys (including lead and lead-bismuth alloys) as coolants, are among the main candidate reactor types for fourth-generation nuclear energy systems due to their excellent nuclear waste transmutation and nuclear fuel breeding capabilities, as well as their high safety and economic efficiency. The main nuclear pump is considered the heart of the reactor, and the pump impeller, as a key flow-through component of the main nuclear pump, is subjected to erosion from high-temperature, high-density, and high-velocity liquid lead alloys. Lead-based reactor pump impellers place high demands on the wear resistance and corrosion resistance of the materials used. Developing a novel protective coating resistant to high-velocity lead alloy erosion corrosion is of significant scientific importance and engineering application value for the development of lead-based reactors. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a coating with good compatibility with the pump impeller substrate and excellent wear resistance and resistance to lead alloy erosion corrosion, as well as a method for its preparation. This invention proposes a double-layer coating design and preparation process, focusing on improving the coating's resistance to lead alloy erosion and enhancing the adhesion between the coating and the substrate. The outer layer employs a TiAlSiN cermet coating that combines wear resistance and corrosion resistance. The inner layer utilizes a high-entropy alloy coating with strong compositional design and excellent comprehensive performance. Considering that lead-based reactor pump impellers are typically made of austenitic steel, selecting Fe and Cr as the main components of the high-entropy alloy coating can improve its adhesion to the pump impeller substrate material and slow down element diffusion between the coating and the metal substrate. Selecting Mo and Nb as the main components of the high-entropy alloy coating can increase the coating hardness and improve its wear resistance. Simultaneously, to improve the high-entropy alloy coating's resistance to lead alloy corrosion, strong oxidizing elements Ti and Al are added as main components, and rare earth element Y is added to improve the density of the oxide layer. Furthermore, the inner high-entropy alloy coating and the outer TiAlSiN coating contain some of the same elements, which also improves the adhesion between the inner and outer coatings. The fabrication process employs the versatile and highly stable magnetron sputtering technology to ensure coating quality.

[0004] The present invention solves the above-mentioned technical problems by adopting the following technical solutions: An anti-erosion coating for a lead-based reactor pump impeller includes an inner layer and an outer layer. The inner layer is a FeCrNbMoTiAlY high-entropy alloy coating, and the outer layer is a TiAlSiN cermet coating. As one of the preferred embodiments of the present invention, the thickness of the inner layer is 1-2 μm, and the thickness of the outer layer is 1-2 μm.

[0005] A method for preparing an anti-erosion coating for a lead-based reactor pump impeller, employing magnetron sputtering, includes the following specific steps: S1. High-entropy alloy targets are prepared by combining magnetic levitation melting and hot isostatic pressing, and TiAlSi targets are prepared by hot isostatic pressing.

[0006] S2. Use sandpaper to grind the surface of the pre-coated steel substrate and use diamond polishing paste for mechanical polishing. S3. A high-entropy alloy coating is prepared on the surface of the steel substrate after polishing in step S2 using magnetron sputtering. The high-entropy alloy target prepared in step S1 is fixed on the cathode, and the polished steel substrate is placed on the anode. Positive ions generated by the discharge fly towards the cathode under the action of the electric field and collide with the atoms on the target surface to form target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a high-entropy alloy coating.

[0007] S4. A TiAlSiN coating is prepared on the surface of the high-entropy alloy coating in step S3 using magnetron sputtering. The TiAlSi target material prepared in step S1 is fixed on the cathode, and the steel substrate coated with the high-entropy alloy coating prepared in step S3 is placed on the anode. Positive ions generated by the discharge fly towards the cathode under the action of the electric field and collide with the atoms on the target surface, thereby forming target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form the TiAlSiN coating.

[0008] As a preferred embodiment of the present invention, in step S1, the specific preparation method of the high-entropy alloy target for inner coating magnetron sputtering is as follows: Pure elemental bulk materials of Fe, Cr, Nb, Mo, Ti, Al, and Y are used as raw materials, with a purity higher than 99.9 wt%. According to the alloy composition and atomic percentage, Fe, Cr, Nb, Mo, Ti, Al, and Y are placed in a magnetically levitated crucible, wherein the atomic percentage of Fe is 30-50 at%, the atomic percentage of Cr is 15-20 at%, the atomic percentage of Nb is 5-10 at%, the atomic percentage of Mo is 5-10 at%, the atomic percentage of Ti is 10-15 at%, the atomic percentage of Al is 5-18 at%, and the atomic percentage of Y is 0-0.005 at. In the melting process, the vacuum level inside the furnace is evacuated to 0~0.001 Pa, then argon gas is introduced at 0.04~0.07 Pa before heating begins. The metal in the crucible is gradually melted until all elements are melted and completely suspended. Electromagnetic stirring is then performed for 3~5 minutes to homogenize the alloy composition. Finally, the alloy is cast and cooled to prepare a high-entropy alloy block. The melted high-entropy alloy block is then placed in a hot isostatic pressing furnace and heated at a rate of 5~10℃ / min until the sintering temperature reaches 1150~1350℃, the sintering pressure is 80~200MPa, and the temperature is held for 30~90 minutes, followed by cooling. After removing the high-entropy alloy, it is machined to prepare a high-entropy alloy target for magnetron sputtering with a thickness of 5 mm.

[0009] As a preferred embodiment of the present invention, the specific preparation method of the TiAlSi target for magnetron sputtering with an outer coating in step S1 is as follows: Pure elemental powders of Ti, Al, and Si are used as raw materials, with a purity higher than 99.9 wt% and a particle size lower than 30 μm. Ti, Al, and Si are placed into a designed and manufactured casing according to the stated composition and atomic percentage, wherein the atomic percentage of Ti is 40-50 at%, the atomic percentage of Al is 40-50 at%, and the atomic percentage of Si is 1-10 at%. The casing filled with powder is vacuumed and sealed, then placed in a furnace and heated at a rate of 5-10 °C / min until the sintering temperature reaches 1600-2000 °C, the sintering pressure is 150-200 MPa, and the temperature is held for 30-90 min, followed by cooling. After removing the casing, the TiAlSi target for magnetron sputtering is prepared by machining, with a target thickness of 5 mm.

[0010] As one of the preferred embodiments of the present invention, in step S2, the surface of the pre-coated steel substrate is polished sequentially with 400-2000 grit sandpaper, and then polished sequentially with diamond polishing paste of grades W2.5, W1, and W0.01. The polished steel substrate is placed in a beaker containing anhydrous ethanol and ultrasonically cleaned at below 50°C for 20 minutes, then placed in a beaker containing acetone and ultrasonically cleaned at below 50°C for 20 minutes, and finally placed in a beaker containing deionized water and ultrasonically cleaned at below 50°C for 20 minutes. After drying in a vacuum drying oven, it is placed in a sputtering chamber.

[0011] As one of the preferred embodiments of the present invention, in step S3, the specific magnetron sputtering process is as follows: sputtering power 100~400W, working gas pressure 0.1~1Pa, transmission speed 1~5m / min, sputtering gas is Ar gas (purity 99.999%), gas flow rate 10~60ml / min, sputtering time 200~400min, and target-substrate distance 20~80mm.

[0012] As one of the preferred embodiments of the present invention, in step S4, the specific magnetron sputtering process is as follows: sputtering power 200~600W, working gas pressure 0.1~1Pa, transmission speed 1~5m / min, sputtering gas is N2+Ar gas (purity 99.999%), N2 gas flow rate is 0.5~10ml / min, Ar gas flow rate is 10~50ml / min, sputtering time is 200~400min, and target-substrate distance is 20~80mm.

[0013] The advantages of the prior art in this invention project are: The coating of this invention has a double-layer structure. The outer layer consists of a TiAlSiN coating with good wear resistance and excellent resistance to lead alloy corrosion, which can improve the resistance of the pump impeller to lead alloy erosion corrosion. The inner layer consists of a high-entropy alloy coating with chemical composition and thermal expansion coefficient matching the metal substrate, which can improve the adhesion between the coating and the substrate. At the same time, the high-entropy alloy coating itself also has good resistance to lead alloy corrosion and high hardness, which can extend the service life of the coating. The coating preparation process of this invention results in uniform coating composition, strong adhesion between the coating and the substrate, and good coating density, which is expected to solve the engineering application problem of resisting high-velocity lead alloy erosion in lead-based reactor pump impellers. Detailed Implementation

[0014] The specific embodiments of the present invention will be described in detail below. This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0015] Example 1: This embodiment provides an anti-erosion coating for a lead-based reactor pump impeller, which employs a double-layer structure. The inner layer of the double-layer structure consists of a FeCrNbMoTiAlY high-entropy alloy coating with chemical composition and thermal expansion coefficient matching the metal substrate and exhibiting good resistance to lead and bismuth corrosion. The outer layer consists of a TiAlSiN cermet coating with good wear resistance and resistance to lead alloy corrosion.

[0016] The above-mentioned method for preparing the anti-erosion coating for lead-based reactor pump impellers: S1. Preparation of targets for magnetron sputtering Inner layer: The target material for magnetron sputtering is a high-entropy alloy, prepared using a combination of magnetic levitation melting and hot isostatic pressing. The preparation method is as follows: pure elemental bulk materials of Fe, Cr, Nb, Mo, Ti, Al, and Y are used as raw materials, with a purity higher than 99.9 wt%. Fe, Cr, Nb, Mo, Ti, Al, and Y are placed in a magnetic levitation crucible with atomic percentages of 42 at%, 18 at%, 5 at%, 8 at%, 12 at%, 15 at%, and 0.003 at%, respectively. During the melting process, the vacuum level in the furnace is evacuated to 0-0.001 Pa, then argon gas is introduced at 0.06 Pa before heating begins. The metal in the crucible is gradually melted until all elements are melted and suspended. Electromagnetic stirring is then performed for 5 minutes to homogenize the alloy composition. Finally, the heating power is gradually adjusted, the power is turned off, and the mixture is poured and cooled to prepare the high-entropy alloy bulk material. The molten high-entropy alloy block was then placed in a hot isostatic pressing furnace and heated at a rate of 8°C / min until the sintering temperature reached 1200°C and the sintering pressure was 150 MPa. The sintering was held for 90 minutes and then cooled. The high-entropy alloy was then removed and machined to prepare a high-entropy alloy target for magnetron sputtering with a thickness of 5 mm.

[0017] Outer Layer: The target material for magnetron sputtering is TiAlSi, prepared using a hot isostatic pressing (HIP) method. Pure elemental powders of Ti, Al, and Si are used as raw materials, with a purity higher than 99.9 wt%, a particle size lower than 30 μm, and an atomic percentage of 45 at% for Ti, 45 at% for Al, and 10 at% for Si. Ti, Al, and Si are placed in a pre-designed casing. The casing filled with powder is then vacuum-sealed, placed in a furnace, and heated at a rate of 8 °C / min until the sintering temperature reaches 2000 °C, the sintering pressure is 200 MPa, and the temperature is held for 90 min, followed by cooling. After removing the casing, the TiAlSi target material for magnetron sputtering is prepared by machining, with a target thickness of 5 mm.

[0018] S2. Grind the surface of the pre-coated 316L steel substrate with 400~2000 grit sandpaper in sequence. Then polish the ground steel substrate with diamond polishing paste of grades W2.5, W1, and W0.01 in sequence. Place the polished 316L steel substrate in a beaker containing anhydrous ethanol and ultrasonically clean it at a temperature below 50°C for 20 minutes. Then place it in a beaker containing acetone and ultrasonically clean it at a temperature below 50°C for 20 minutes. Finally, place it in a beaker containing deionized water and ultrasonically clean it at a temperature below 50°C for 20 minutes. After drying in a vacuum drying oven, place it in the sputtering chamber.

[0019] S3. An inner high-entropy alloy coating is prepared on the surface of the 316L steel substrate after polishing in step S2 using magnetron sputtering. The high-entropy alloy target prepared in step S1 is fixed on the cathode, and the polished 316L steel substrate is placed on the anode. Positive ions generated by the discharge fly towards the cathode under the action of the electric field and collide with the atoms on the target surface, thereby forming target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a high-entropy alloy coating. The specific magnetron sputtering process is as follows: sputtering power 300W, working gas pressure 0.8Pa, transmission speed 3m / min, sputtering gas is Ar gas (purity 99.999%), Ar gas flow rate 40ml / min, sputtering time 250min, target-substrate distance 48mm.

[0020] S4. A TiAlSiN coating is prepared on the surface of the coating prepared in step S3 using magnetron sputtering. The TiAlSi target material prepared in step S1 is fixed on the cathode, and the 316L steel substrate with the coating prepared in step S3 is placed on the anode. The specific magnetron sputtering process is as follows: sputtering power 500W, working gas pressure 0.8Pa, transmission speed 3m / min, sputtering gas is N2 + Ar gas (purity 99.999%), N2 gas flow rate 1ml / min, Ar gas flow rate 40ml / min, sputtering time 200min, target-substrate distance 48mm.

[0021] Example 2: This embodiment provides an anti-erosion coating for a lead-based reactor pump impeller, which employs a double-layer structure. The inner layer of the double-layer structure consists of a FeCrNbMoTiAlY high-entropy alloy coating with chemical composition and thermal expansion coefficient matching the metal substrate and exhibiting good resistance to lead and bismuth corrosion. The outer layer consists of a TiAlSiN cermet coating with good wear resistance and resistance to lead alloy corrosion.

[0022] The above-mentioned method for preparing the anti-erosion coating for lead-based reactor pump impellers: S1. Preparation of targets for magnetron sputtering Inner layer: The target material for magnetron sputtering is a high-entropy alloy, prepared using a combination of magnetic levitation melting and hot isostatic pressing. The preparation method involves using pure elemental bulk materials of Fe, Cr, Nb, Mo, Ti, Al, and Y as raw materials, with a purity exceeding 99.9 wt%. Fe, Cr, Nb, Mo, Ti, Al, and Y are placed in a magnetically levitation crucible with atomic percentages of 44 at%, 20 at%, 5 at%, 7 at%, 12 at%, 12 at%, and 0.001 at%, respectively. During the melting process, the vacuum level in the furnace is evacuated to 0-0.001 Pa, then argon gas is introduced at 0.06 Pa before heating begins. The metal in the crucible is gradually melted until all elements are completely melted and suspended, then electromagnetically stirred for 5 minutes. Finally, the heating power is gradually adjusted, the power is turned off, and the mixture is poured and cooled to prepare the high-entropy alloy bulk material. The molten high-entropy alloy block was then placed in a hot isostatic pressing furnace and heated at a rate of 8°C / min until the sintering temperature reached 1200°C and the sintering pressure was 180 MPa. The sintering was held for 90 minutes and then cooled. The high-entropy alloy was then removed and machined to prepare a high-entropy alloy target for magnetron sputtering with a thickness of 5 mm.

[0023] Outer Layer: The target material for magnetron sputtering is TiAlSi, prepared using a hot isostatic pressing (HIP) method. Pure elemental powders of Ti, Al, and Si are used as raw materials, with a purity higher than 99.9 wt%, a particle size lower than 30 μm, and an atomic percentage of 42 at% for Ti, 48 at% for Al, and 10 at% for Si. Ti, Al, and Si are placed in a pre-designed casing. The casing filled with powder is then vacuum-sealed, placed in a furnace, and heated at a rate of 8 °C / min until the sintering temperature reaches 2000 °C, the sintering pressure is 200 MPa, and the temperature is held for 80 min, followed by cooling. After removing the casing, the TiAlSi target material for magnetron sputtering is prepared by machining, with a target thickness of 5 mm.

[0024] S2. Grind the surface of the pre-coated 316L steel substrate with 400~2000 grit sandpaper in sequence. Then polish the ground steel substrate with diamond polishing paste of grades W2.5, W1, and W0.01 in sequence. Place the polished 316L steel substrate in a beaker containing anhydrous ethanol and ultrasonically clean it at below 50°C for 20 minutes. Then place it in a beaker containing acetone and ultrasonically clean it at below 50°C for 20 minutes. Finally, place it in a beaker containing deionized water and ultrasonically clean it at below 50°C for 20 minutes. After drying in a vacuum drying oven, place it in the sputtering chamber.

[0025] S3. An inner high-entropy alloy coating is prepared on the surface of the 316L steel substrate after polishing in step S2 using magnetron sputtering. The high-entropy alloy target prepared in step S1 is fixed on the cathode, and the polished 316L steel substrate is placed on the anode. Positive ions generated by the discharge fly towards the cathode under the action of the electric field and collide with the atoms on the target surface, thereby forming target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a high-entropy alloy coating. The specific magnetron sputtering process is as follows: sputtering power 150W, working gas pressure 0.1Pa, transmission speed 2m / min, sputtering gas is Ar gas (purity 99.999%), Ar gas flow rate 40ml / min, sputtering time 120min, target-substrate distance 45mm.

[0026] S4. A TiAlSiN coating is prepared on the surface of the coating prepared in step S3 using magnetron sputtering. The TiAlSi bulk target prepared in step S1 is fixed on the cathode, and the 316L steel substrate with the coating prepared in step S3 is placed on the anode. The specific magnetron sputtering process is as follows: sputtering power 200W, working gas pressure 0.1Pa, transmission speed 2m / min, sputtering gas is N2 + Ar gas (purity 99.999%), N2 gas flow rate 0.8ml / min, Ar gas flow rate 40ml / min, sputtering time 120min, target-substrate distance 45mm.

[0027] Example 3: Performance testing of anti-erosion coating for lead-based reactor pump impellers: The resistance of the coating to lead-bismuth alloy erosion corrosion was tested using a liquid metal rotary corrosion apparatus. During the test, the temperature of the liquid metal on the coating surface was 350 °C, the liquid metal velocity was 5 m / s, and the corrosion time was 1000 h. Test samples included a comparative sample, a sample from Example 1, and a sample from Example 2. The comparative sample was an uncoated 316L sample, the Example 1 sample was a 316L sample coated with the anti-erosion coating prepared in Example 1, and the Example 2 sample was a 316L sample coated with the anti-erosion coating prepared in Example 2. The test results are shown in Table 1. The results show that compared to the uncoated sample, the corrosion weight loss of the coated 316L sample was significantly reduced, indicating that the coating can effectively improve the resistance of the 316L sample to lead-bismuth erosion corrosion.

[0028] Table 1 Performance test results of the coating

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anti-erosion coating for a lead-based reactor pump impeller, characterized in that, It includes an inner layer and an outer layer. The inner layer is a FeCrNbMoTiAlY high-entropy alloy coating, and the outer layer is a TiAlSiN cermet coating. The preparation method of the anti-erosion coating for the lead-based reactor pump impeller includes the following steps: S1. High-entropy alloy targets are prepared by combining magnetic levitation melting method with hot isostatic pressing method, and TiAlSi targets are prepared by hot isostatic pressing method. S2. Use sandpaper to grind the surface of the pre-coated steel substrate and use diamond polishing paste for mechanical polishing. S3. Using magnetron sputtering, an inner high-entropy alloy coating is prepared on the surface of the steel substrate after polishing in step S2. The high-entropy alloy target prepared in step S1 is fixed on the cathode, and the polished steel substrate is placed on the anode. Positive ions generated by discharge fly to the cathode under the action of electric field and collide with the atoms on the target surface to form target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a high-entropy alloy coating. S4. Using magnetron sputtering, a TiAlSiN coating is prepared on the surface of the high-entropy alloy coating in step S3. The TiAlSi target material prepared in step S1 is fixed on the cathode, and the steel substrate coated with the high-entropy alloy coating prepared in step S3 is placed on the anode. Positive ions generated by discharge fly towards the cathode under the action of the electric field and collide with the atoms on the target surface to form target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a TiAlSiN coating. In step S1, the preparation method of the high-entropy alloy target for inner layer magnetron sputtering is as follows: pure element bulk materials of Fe, Cr, Nb, Mo, Ti, Al, and Y are used as raw materials; the metal elements are placed in a magnetically levitated crucible according to the following alloy composition and atomic percentage: Fe atomic percentage is 30~50at%, Cr atomic percentage is 15~20at%, Nb atomic percentage is 5~10at%, Mo atomic percentage is 5~10at%, Ti atomic percentage is 10~15at%, Al atomic percentage is 5~18at%, and Y atomic percentage is 0~0.005at%. Then, a vacuum is drawn and argon gas is filled, and the mixture is heated until all elements melt and are in a completely magnetically levitated state. Then, stirring is started to homogenize the alloy. Finally, the mixture is cast and cooled to prepare a high-entropy alloy bulk material with uniform composition. The high-entropy alloy target for magnetron sputtering is prepared by hot isostatic pressing and machining; the target thickness is 5mm. In step S1, the preparation method of the TiAlSi target for outer layer magnetron sputtering is as follows: pure elemental powder materials of Ti, Al and Si are used as raw materials with a particle size of less than 30 μm, the atomic percentage of Ti is 40-50 at%, the atomic percentage of Al is 40-50 at%, and the atomic percentage of Si is 1-10 at%. TiAlSi bulk material is prepared by mixing Ti, Al and Si powders by hot isostatic pressing, and then TiAlSi target material is prepared by mechanical processing; the target material thickness is 5 mm.

2. The anti-erosion coating for a lead-based reactor pump impeller according to claim 1, characterized in that, The thickness of the inner layer is 1-2 μm, and the thickness of the outer layer is 1-2 μm.

3. A method for preparing an anti-erosion coating for a lead-based reactor pump impeller according to claim 1, characterized in that, Includes the following steps: S1. High-entropy alloy targets are prepared by combining magnetic levitation melting method with hot isostatic pressing method, and TiAlSi targets are prepared by hot isostatic pressing method. S2. Use sandpaper to grind the surface of the pre-coated steel substrate and use diamond polishing paste for mechanical polishing. S3. Using magnetron sputtering, an inner high-entropy alloy coating is prepared on the surface of the steel substrate after polishing in step S2. The high-entropy alloy target prepared in step S1 is fixed on the cathode, and the polished steel substrate is placed on the anode. Positive ions generated by discharge fly to the cathode under the action of electric field and collide with the atoms on the target surface to form target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a high-entropy alloy coating. S4. Using magnetron sputtering, a TiAlSiN coating is prepared on the surface of the high-entropy alloy coating in step S3. The TiAlSi target material prepared in step S1 is fixed on the cathode, and the steel substrate coated with the high-entropy alloy coating prepared in step S3 is placed on the anode. Positive ions generated by discharge fly towards the cathode under the action of the electric field and collide with the atoms on the target surface to form target sputtered atoms. The target sputtered atoms are deposited on the substrate surface to form a TiAlSiN coating.

4. The method for preparing the anti-erosion coating for lead-based reactor pump impellers according to claim 3, characterized in that, In step S1, the preparation method of the high-entropy alloy target for inner layer magnetron sputtering is as follows: pure element bulk materials of Fe, Cr, Nb, Mo, Ti, Al, and Y are used as raw materials; the metal elements are placed in a magnetically levitated crucible according to the following alloy composition and atomic percentage: Fe atomic percentage is 30~50at%, Cr atomic percentage is 15~20at%, Nb atomic percentage is 5~10at%, Mo atomic percentage is 5~10at%, Ti atomic percentage is 10~15at%, Al atomic percentage is 5~18at%, and Y atomic percentage is 0~0.005at%. Then, a vacuum is drawn and argon gas is filled in, and the mixture is heated until all elements melt and are in a completely magnetically levitated state. Then, stirring is started to homogenize the alloy. Finally, the mixture is cast and cooled to prepare a high-entropy alloy bulk material with uniform composition. The high-entropy alloy target for magnetron sputtering is prepared by hot isostatic pressing and machining; the target thickness is 5mm.

5. The method for preparing the anti-erosion coating for lead-based reactor pump impellers according to claim 3, characterized in that, In step S1, the preparation method of the TiAlSi target for outer layer magnetron sputtering is as follows: pure elemental powder materials of Ti, Al and Si are used as raw materials with a particle size of less than 30 μm, the atomic percentage of Ti is 40-50 at%, the atomic percentage of Al is 40-50 at%, and the atomic percentage of Si is 1-10 at%. TiAlSi bulk material is prepared by mixing Ti, Al and Si powders by hot isostatic pressing, and then TiAlSi target material is prepared by mechanical processing; the target material thickness is 5 mm.

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