High-entropy crystal / amorphous nano-metal multilayer film and preparation method thereof

Abstract

The invention discloses a high-entropy crystal / amorphous nano-metal multilayer film and a preparation method thereof, and belongs to the field of nano-metal multilayer film coating materials, and the nano-metal multilayer film comprises TaWMoCrZr layers and CrMoY layers which are alternately stacked; the thickness of the TaWMoCrZr layer ranges from 5 nm to 100 nm, and the thickness of the CrMoY layer ranges from 1.25 nm to 25 nm. The TaWMoCrZr layer is in a nanocrystalline form, and the CrMoY layer is in an amorphous form; the nano metal multilayer film is prepared by adopting a magnetron sputtering method, the thickness of a component layer is regulated and controlled by controlling the sputtering time, the prepared TaWMoCrZr / CrMoY coating is of a nano multilayer structure, the layer interface is clear and straight, the components are uniform, the tissue is compact, the mechanical property is excellent, self-regulation component segregation is realized through the mixing enthalpy design, the thermal stability is good, and the preparation process is simple. And the application range of the multilayer film coating is expanded.

Description

Technical Field

[0001] The invention relates to the field of nano metal multilayer film coating materials, in particular to a high entropy crystal / amorphous nano metal multilayer film and a preparation method thereof. Background Art

[0002] Compared with traditional metal materials, nano-metal multilayer films have excellent comprehensive performance, with a higher combination of strength and plasticity, better resistance to radiation damage, and stronger resistance to fatigue failure. Therefore, they have the potential to become one of the choices for materials serving in extreme environments, such as nuclear fuel cladding materials. Currently, there are many preparation methods for depositing nano-metal multilayer film coatings, among which magnetron sputtering is a relatively mature coating preparation technology due to its low-temperature operation, controllable deposition rate, excellent film quality, precise process, and good repeatability.

[0003] However, the lead-bismuth fast reactor cladding materials in the fourth-generation nuclear reactors not only need to have sufficient toughness to resist the synergistic effects of complex stresses (such as slow tension, creep, fatigue, etc.), but also have corrosion resistance to lead-bismuth corrosion. Currently, several high-quality alternative materials are preferred: iron / Ma steel (F / M steel) and austenitic steel. F / M steel has fatal defects such as radiation embrittlement and low strength at high temperatures; the Ni element in austenitic steel is easily dissolved into the lead-bismuth liquid metal, resulting in poor lead-bismuth compatibility of austenitic steel. Therefore, in order to ensure the stable and normal service of nuclear fuel cladding materials, it is of great application value and significance to design nano-metal multilayer coatings with excellent mechanical properties, thermal stability and corrosion resistance. TaWMoCrZr high entropy crystal monolayer film has excellent thermal stability, and Ta, W, Mo, Cr, Zr, and Y elements are insoluble in lead and bismuth. At the same time, the CrMoY monolayer film has a uniform amorphous structure without corrosion-prone structural defects such as grain boundaries. Therefore, how to combine TaWMoCrZr and CrMoY as crystal layers and amorphous layers to form a composite material so that the composite material has the performance advantages of the two films to improve the protective performance of the lead-bismuth fast reactor cladding material. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a high-entropy crystalline / amorphous nanometal multilayer film and a preparation method thereof, wherein the nanometal multilayer film coating has a clear and straight layer interface, a uniform microstructure, and excellent high-temperature structural stability and mechanical properties.

[0005] The present invention is achieved through the following technical solutions: A high entropy crystal / amorphous nano-metal multilayer film, comprising TaWMoCrZr layers and CrMoY layers alternately stacked; The thickness of the TaWMoCrZr layer is 5-100 nm, and the thickness of the CrMoY layer is 1.25-25 nm; The TaWMoCrZr layer is in a nanocrystalline state, and the CrMoY layer is in an amorphous state.

[0006] Preferably, the nano-indentation hardness of the nano-metal multilayer film is 9.5 to 10.5 GPa, and the Young's modulus is 161 to 174 GPa.

[0007] Preferably, in the TaWMoCrZr layer, the atomic percentage ratio of the four elements Ta, W, Mo and Cr is 1:1:1:1, and the atomic percentage of the Zr element is 16.8 at.%.

[0008] Preferably, the ratio of the element atomic percentages of Cr, Mo and Y in the CrMoY layer is 1:1:1.

[0009] A method for preparing a high entropy crystal / amorphous nanometal multilayer film comprises the following steps: Step 1, cleaning and drying the substrate surface; Step 2, vacuum etching the substrate cleaned in step 1.

[0010] Step 3, using a combination target of a TaWMoCr alloy target and a Zr target, and a TaWMoCr alloy target to alternately magnetron sputter deposit TaWMoCrZr crystal layers and TaWMoCr layers on a substrate to obtain a nano-metal multilayer film; During the magnetron sputtering process, the DC power of the TaWMoCr alloy target is 200 W, the RF power of the Zr target is 100 W, the DC power of the CrMoY alloy target is 200 W, and the total deposition time is 7496 to 9664 seconds; Step 4: Cool the nano-metal multilayer film to room temperature in the furnace to obtain a high entropy crystalline / amorphous nano-metal multilayer film.

[0011] Preferably, the method of alternately depositing the TaWMoCrZr crystal layer and the TaWMoCr layer by magnetron sputtering in step 3 is as follows: Firstly, a TaWMoCrZr crystal layer is sputtered on a substrate using a combination target of a TaWMoCr alloy target and a Zr target; Then, a CrMoY amorphous layer is deposited by sputtering using a CrMoY alloy target; The above process is repeated, and TaWMoCrZr crystal layers and CrMoY amorphous layers are alternately deposited using a combined target and a CrMoY alloy target until the preset conditions are reached to obtain a nano-metal multilayer film.

[0012] Preferably, the deposition gas pressure of the magnetron sputtering is set to 0.3 Pa, and the substrate rotation speed is 15 r / min.

[0013] Preferably, the TaWMoCr alloy target and the CrMoY alloy target are both equiatomic targets.

[0014] Preferably, the cooling time in step 4 is 2-3 hours.

[0015] An application of a high entropy crystal / amorphous nanometal multilayer film, wherein the nanometal multilayer film is applied to a lead-bismuth fast reactor cladding in a nuclear reactor.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention proposes a high entropy crystal / amorphous nano-metal multilayer coating, which is unique in that the TaWMoCrZr nanocrystalline layer and the CrMoY amorphous layer are alternately stacked. This design cleverly utilizes the characteristics that elements such as Ta, W, Mo, Cr, Zr, and Y are insoluble in lead-bismuth alloys, as well as the excellent thermal stability exhibited by the TaWMoCrZr high entropy crystal monolayer film and the uniform amorphous structure formed by the CrMoY monolayer film. Secondly, the TaWMoCrZr layer exists in a nanocrystalline form, while the CrMoY layer presents an amorphous form. The two are alternately superimposed to form a multilayer film structure with a clear and straight interface, uniform composition, and dense organization. This crystal / amorphous nano-multilayer film not only has excellent mechanical properties, but also effectively captures irradiation defects and enhances the overall stability of the coating due to the heterogeneous characteristics of the crystal / amorphous interface. More importantly, the present invention designs a refractory high entropy alloy component by rationally selecting a high-melting-point metal element that is insoluble in lead-bismuth alloys as a high-entropy component, so that this high-entropy crystal / amorphous nano-multilayer film coating performs well in thermal stability. This design concept not only improves the corrosion resistance of the coating, but also enables it to demonstrate excellent comprehensive performance when facing extreme environments in nuclear energy fields such as lead-bismuth fast reactors. Compared with protective coatings prepared by prior art, the high-entropy nanometal multilayer film of the present invention has successfully achieved comprehensive improvements in mechanical properties, thermal stability and corrosion resistance by carefully selecting alloy elements and optimizing preparation methods. This innovative design not only expands the application scope of multilayer film coatings, but also provides strong material support for engineering needs in nuclear energy fields such as lead-bismuth fast reactors, demonstrating its great potential as a material for service in extreme environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1This is a TEM cross-sectional photograph of the TaWMoCrZr / CrMoY high entropy crystalline / amorphous nano multilayer film prepared in Example 1 of the present invention; Figure 2 This is a high-resolution photograph of the TaWMoCrZr / CrMoY high-entropy crystalline / amorphous nano-multilayer film prepared in Example 1 of the present invention.

[0019] Figure a is a high-resolution photo of the TaWMoCrZr crystal layer in the TaWMoCrZr / CrMoY high-entropy crystal / amorphous nano-multilayer film; Figure b is a high-resolution photo of the CrMoY amorphous layers in the TaWMoCrZr / CrMoY high-entropy crystal / amorphous nano-multilayer film; Figure 3 This is an EDS elemental surface scan image of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film prepared in Example 1 of the present invention.

[0020] Figure 4 Nanoindentation hardness results of TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer films with different modulation periods of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0023] Regarding the problem of how to combine TaWMoCrZr and CrMoY to form a composite material, and the composite material formed needs to have an effective protective effect in extreme environments, the composite material must have a uniform and dense microstructure and excellent performance, which depends largely on the selection of its preparation technology and process parameters. Therefore, how to accurately select the magnetron sputtering process parameters and modulation parameters to regulate the microstructure of the coating and prepare a new high-entropy nano-multilayer film coating with excellent mechanical properties, thermal stability and corrosion resistance is a key issue in the preparation of composite materials.

[0024] Based on the above problems, the present application provides a high entropy crystalline / amorphous nanometal multilayer film, comprising TaWMoCrZr layers and CrMoY layers alternately stacked; The thickness of the TaWMoCrZr layer is 5-100 nm, the thickness of the CrMoY layer is 1.25-25 nm, and the thickness of the nano-metal multilayer film is 1 μm.

[0025] The TaWMoCrZr layer is in nanocrystalline form, the atomic percentage ratio of the four elements Ta, W, Mo and Cr is 1:1:1:1, and the atomic percentage of the Zr element is 16.8 at.%.

[0026] The CrMoY layer is in an amorphous state, and the atomic percentage ratio of the three elements Cr, Mo, and Y is 1:1:1.

[0027] The nanoindentation hardness of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating is 9.5-10.5 GPa, and the Young's modulus is 161-174 GPa.

[0028] The present application discloses a high-entropy crystal / amorphous nano-metal multilayer film, wherein the TaWMoCrZr high-entropy crystal layer has excellent thermal stability, and the elements Ta, W, Mo, Cr, Zr, and Y are insoluble in lead and bismuth. Meanwhile, the CrMoY single-layer film has a uniform amorphous structure without corrosion-prone structural defects such as grain boundaries. The TaWMoCrZr high-entropy crystal layer and the CrMoY single-layer film are coupled together by magnetron sputtering technology to form a multilayer film structure, and the multilayer film has a clear and flat interface, uniform composition, and dense structure, and has excellent mechanical properties, thermal stability, and corrosion resistance.

[0029] Correspondingly, based on the above-mentioned high entropy crystal / amorphous nano-metal multilayer film, the present application also provides a method for preparing the high entropy crystal / amorphous nano-metal multilayer film, comprising the following steps: Step 1: Ultrasonic cleaning and drying of the silicon substrate surface is performed to improve the bonding strength between the coating and the substrate.

[0030] Specifically, the silicon substrate is polished on one side, and then ultrasonically cleaned in acetone and ethanol for 15 minutes respectively and then quickly dried, so that the surface of the silicon substrate is clean, free of stains and dust, and the roughness is below 0.8 nm, which is beneficial to improving the bonding strength between the coating and the substrate.

[0031] Step 2: vacuum-etch the substrate cleaned in step 1.

[0032] Specifically, the silicon substrate after ultrasonic cleaning is fixed on the base plate and sent to the vacuum coating chamber, and then the back vacuum degree is pumped to 4.0×10 -4 Pa or less. In a high vacuum environment, using Ar+ Ion etching was performed with a power of 200 W and a gas flow rate of 60 sccm for 5 minutes to remove impurities on the substrate surface, which is beneficial to improving the bonding strength between the coating and the substrate.

[0033] Step 3: Using a combination target of a TaWMoCr alloy target and a Zr target, and a TaWMoCr alloy target to alternately magnetron sputter deposit TaWMoCrZr crystal layers and TaWMoCr layers on a substrate.

[0034] Specifically, when the vacuum degree is below 4.0×10-4Pa, a TaWMoCrZr crystal layer is firstly sputtered on the substrate using a combination target of a TaWMoCr alloy target and a Zr target, and then a CrMoY amorphous layer is sputtered using a CrMoY alloy target. Then, the above process is repeated, and TaWMoCrZr crystal layers and CrMoY amorphous layers are alternately deposited using a combination target and a CrMoY alloy target until the preset conditions are met to obtain a nano metal multilayer film.

[0035] During the magnetron sputtering process, the DC power of the TaWMoCr alloy target is 200W, the RF power of the Zr target is 100W, the DC power of the CrMoY alloy target is 200W, the deposition gas pressure is set to 0.3Pa, the substrate speed is 15r / min, the total deposition time is 7496-9664 seconds, and the thickness of the nanometal multilayer film is 1μm.

[0036] The purity of the TaWMoCr alloy target is 99.9wt.% (Ta:W:Mo:Cr=1:1:1:1 at.%), the purity of the Zr target is 99.9wt.%, and the purity of the CrMoY alloy target is 99.9wt.% (Cr:Mo:Y=1:1:1 at.%).

[0037] Step 4: After the deposition is completed, the nano-metal multilayer film is fully cooled to room temperature in a high vacuum coating chamber, and then taken out to obtain a high entropy crystalline / amorphous nano-metal multilayer film.

[0038] The purpose of the furnace cooling process is to avoid debonding and cracking caused by the difference in thermal expansion coefficients between the substrate and the coating material, and to prevent oxidation reactions caused by the coating coming into contact with air at high temperatures.

[0039] The principle of this method for preparing high entropy crystal / amorphous nano multilayer film coatings is to fill a vacuum chamber with an appropriate amount of argon gas and apply a high voltage between the cathode target and the anode. Under the action of the electric field, the electrons are accelerated and collide with the argon molecules, causing them to ionize and produce Ar⁺ and electrons. These Ar⁺ are accelerated under the action of the electric field to bombard the target surface, so that the target atoms or molecules obtain sufficient kinetic energy to break away from the target surface and form sputtered particles. Figure 1As shown, the prepared TaWMoCrZr / CrMoY high entropy crystal / amorphous nano-multilayer coating has a morphology of a crystal / amorphous multilayer, wherein the TaWMoCrZr layer is in a nanocrystalline form, the CrMoY layer is in an amorphous form, the layer interface is clear and straight, the composition is uniform, and the structure is dense.

[0040] Example 1 A method for preparing a high entropy crystal / amorphous nanometal multilayer film comprises the following steps: Step 1, ultrasonically cleaning the polished Si (111) substrate in acetone and anhydrous ethanol for 15 minutes respectively and then drying to remove impurities on the surface of the silicon substrate; Step 2: Fix the silicon substrate on the base plate and automatically transport it into the magnetron sputtering vacuum coating chamber until the back vacuum is 4.0×10 -4 Pa, the etching power is 200W, the etching pressure is 1.0Pa, and the time is 5min.

[0041] Step 3, start magnetron sputtering deposition of TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating.

[0042] First, argon gas was introduced for 30 s, pre-sputtering was performed for 10 s, and TaWMoCr alloy target and Zr target were co-sputtered to prepare TaWMoCrZr crystal layer. The DC power of TaWMoCr alloy target was 200 W, and the RF power of Zr target was 100 W.

[0043] Then, a CrMoY amorphous layer is prepared by using a CrMoY alloy target, and the DC power of the CrMoY alloy target is 200W.

[0044] Secondly, start the co-sputtering of TaWMoCr target and Zr target, and alternately deposit with CrMoY target, the substrate rotation speed is 15 r / min, the deposition gas pressure is set to 0.3Pa, the argon flow rate is 60sccm, the deposition temperature is room temperature, the thickness of the single-layer TaWMoCrZr crystal layer is set to 100nm, the thickness of the single-layer CrMoY amorphous layer is set to 25nm, the number of modulation cycles is 8, and the total film thickness is 1μm.

[0045] Step 4, after the sample is naturally cooled in the vacuum coating chamber for 2-3 hours to room temperature, it is taken out to obtain a TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating with a thickness of about 1.00 μm.

[0046] The microstructure of the prepared TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was characterized. The morphology of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was crystal / amorphous nano multilayer film, in which the TaWMoCrZr layer was in a nanocrystalline form, the CrMoY layer was in an amorphous form, the multilayer film interface was clear and straight, the composition was uniform, and the structure was dense.

[0047] Example 2 A method for preparing a high entropy crystal / amorphous nanometal multilayer film comprises the following steps: Step 1, ultrasonically cleaning the polished Si (111) substrate in acetone and anhydrous ethanol for 15 minutes respectively and then drying to remove impurities on the surface of the silicon substrate; Step 2: Fix the silicon substrate on the base plate and automatically transport it into the magnetron sputtering vacuum coating chamber until the back vacuum is 4.0×10 -4 Pa, the etching power is 200W, the etching pressure is 1.0Pa, and the time is 5min.

[0048] Step 3, start magnetron sputtering deposition of TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating.

[0049] First, argon gas was introduced for 30 s, pre-sputtering was performed for 10 s, and TaWMoCr alloy target and Zr target were co-sputtered to prepare TaWMoCrZr crystal layer. The DC power of TaWMoCr alloy target was 200 W, and the RF power of Zr target was 100 W.

[0050] Then, a CrMoY amorphous layer is prepared by using a CrMoY alloy target, and the DC power of the CrMoY alloy target is 200W.

[0051] Secondly, start the co-sputtering of TaWMoCr target and Zr target, and alternately deposit with CrMoY target, the substrate rotation speed is 15 r / min, the deposition gas pressure is set to 0.3Pa, the argon gas flow rate is 60sccm, the deposition temperature is room temperature, the thickness of the single-layer TaWMoCrZr crystal layer is set to 50nm, the thickness of the single-layer CrMoY amorphous layer is set to 12.5nm, the number of periods is 16, and the total film thickness is 1μm.

[0052] Step 4, after the sample is naturally cooled in the vacuum coating chamber for 2-3 hours to room temperature, it is taken out to obtain a TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating with a thickness of about 1.00 μm.

[0053] The microstructure of the prepared TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was characterized. The morphology of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was crystal / amorphous nano multilayer film, in which the TaWMoCrZr layer was in a nanocrystalline form, the CrMoY layer was in an amorphous form, the multilayer film interface was clear and straight, the composition was uniform, and the structure was dense.

[0054] Example 3 A method for preparing a high entropy crystal / amorphous nanometal multilayer film comprises the following steps: Step 1, ultrasonically cleaning the polished Si (111) substrate in acetone and anhydrous ethanol for 15 minutes respectively and then drying to remove impurities on the surface of the silicon substrate; Step 2: Fix the silicon substrate on the base plate and automatically transport it into the magnetron sputtering vacuum coating chamber until the back vacuum is 4.0×10 -4 Pa, the etching power is 200W, the etching pressure is 1.0Pa, and the time is 5min.

[0055] Step 3, start magnetron sputtering deposition of TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating.

[0056] First, argon gas was introduced for 30 s, pre-sputtering was performed for 10 s, and TaWMoCr alloy target and Zr target were co-sputtered to prepare TaWMoCrZr crystal layer. The DC power of TaWMoCr alloy target was 200 W, and the RF power of Zr target was 100 W.

[0057] Then, a CrMoY amorphous layer is prepared by using a CrMoY alloy target, and the DC power of the CrMoY alloy target is 200W.

[0058] Secondly, start the co-sputtering of TaWMoCr target and Zr target, and alternately deposit with CrMoY target, the substrate rotation speed is 15 r / min, the deposition gas pressure is set to 0.3Pa, the argon gas flow rate is 60sccm, the deposition temperature is room temperature, the thickness of the single-layer TaWMoCrZr crystal layer is set to 25nm, the thickness of the single-layer CrMoY amorphous layer is set to 6.25nm, the number of periods is 32, and the total film thickness is 1μm.

[0059] Step 4, after the sample is naturally cooled in the vacuum coating chamber for 2-3 hours to room temperature, it is taken out to obtain a TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating with a thickness of about 1.00 μm.

[0060] The microstructure of the prepared TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was characterized. The morphology of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was crystal / amorphous nano multilayer film, in which the TaWMoCrZr layer was in a nanocrystalline form, the CrMoY layer was in an amorphous form, the multilayer film interface was clear and straight, the composition was uniform, and the structure was dense.

[0061] Example 4 A method for preparing a high entropy crystal / amorphous nanometal multilayer film comprises the following steps: Step 1, ultrasonically cleaning the polished Si (111) substrate in acetone and anhydrous ethanol for 15 minutes respectively and then drying to remove impurities on the surface of the silicon substrate; Step 2: Fix the silicon substrate on the base plate and automatically transport it into the magnetron sputtering vacuum coating chamber until the back vacuum is 4.0×10 -4 Pa, the etching power is 200W, the etching pressure is 1.0Pa, and the time is 5min.

[0062] Step 3, start magnetron sputtering deposition of TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating.

[0063] First, argon gas was introduced for 30 s, pre-sputtering was performed for 10 s, and TaWMoCr alloy target and Zr target were co-sputtered to prepare TaWMoCrZr crystal layer. The DC power of TaWMoCr alloy target was 200 W, and the RF power of Zr target was 100 W.

[0064] Then, a CrMoY amorphous layer is prepared by using a CrMoY alloy target, and the DC power of the CrMoY alloy target is 200W.

[0065] Secondly, start the co-sputtering of TaWMoCr target and Zr target, and alternately deposit with CrMoY target, the substrate rotation speed is 15 r / min, the deposition gas pressure is set to 0.3Pa, the argon gas flow rate is 60sccm, the deposition temperature is room temperature, the thickness of the single-layer TaWMoCrZr crystal layer is set to 10nm, the thickness of the single-layer CrMoY amorphous layer is set to 2.5nm, the number of periods is 80, and the total film thickness is 1μm.

[0066] Step 4, after the sample is naturally cooled in the vacuum coating chamber for 2-3 hours to room temperature, it is taken out to obtain a TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating with a thickness of about 1.00 μm.

[0067] The microstructure of the prepared TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was characterized. The morphology of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was crystal / amorphous nano multilayer, in which the TaWMoCrZr layer was partially amorphous and partially nanocrystalline due to its small layer thickness, and the CrMoY layer was amorphous. The multilayer interface was relatively clear and flat, the composition was uniform, and the structure was dense.

[0068] Example 5 A method for preparing a high entropy crystal / amorphous nanometal multilayer film comprises the following steps: Step 1, ultrasonically cleaning the polished Si (111) substrate in acetone and anhydrous ethanol for 15 minutes respectively and then drying to remove impurities on the surface of the silicon substrate; Step 2: Fix the silicon substrate on the base plate and automatically transport it into the magnetron sputtering vacuum coating chamber until the back vacuum is 4.0×10 -4 Pa, the etching power is 200W, the etching pressure is 1.0Pa, and the time is 5min.

[0069] Step 3, start magnetron sputtering deposition of TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating.

[0070] First, argon gas was introduced for 30 s, pre-sputtering was performed for 10 s, and TaWMoCr alloy target and Zr target were co-sputtered to prepare TaWMoCrZr crystal layer. The DC power of TaWMoCr alloy target was 200 W, and the RF power of Zr target was 100 W.

[0071] Then, a CrMoY amorphous layer is prepared by using a CrMoY alloy target, and the DC power of the CrMoY alloy target is 200W.

[0072] Secondly, TaWMoCr target and Zr target were co-sputtered at the same time, and alternately deposited with CrMoY target, the substrate rotation speed was 15r / min, the deposition gas pressure was set to 0.3Pa, the argon gas flow rate was 60sccm, the deposition temperature was room temperature, the thickness of the single-layer TaWMoCrZr crystal layer was set to 5nm, the thickness of the single-layer CrMoY amorphous layer was set to 1.25nm, the number of periods was 160, and the total film thickness was 1μm.

[0073] Step 4, after the sample is naturally cooled in the vacuum coating chamber for 2-3 hours to room temperature, it is taken out to obtain a TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer film coating with a thickness of about 1.00 μm.

[0074] The microstructure of the prepared TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was characterized. The morphology of the TaWMoCrZr / CrMoY high entropy crystal / amorphous nano multilayer coating was a crystal / amorphous nano multilayer film, in which the TaWMoCrZr layer was partially amorphous and partially nanocrystalline due to its small layer thickness, and the CrMoY layer was amorphous. The interface of the multilayer film was relatively clear and straight, slightly curved compared to the thick multilayer film, with uniform composition and dense structure.

[0075] Figure 1 The TEM cross-sectional photograph of the high entropy crystal / amorphous nano multilayer prepared in Example 1 is shown. Figure 2 This is a high-resolution photograph of the high-entropy crystal / amorphous nano-multilayer film prepared in Example 1. Figure 3 The EDS elemental surface scan image of the high entropy crystal / amorphous nano multilayer film prepared in Example 1 is shown. Figure 4 Nanoindentation hardness results of high entropy crystal / amorphous nano-multilayer coatings with different layer thicknesses are shown.

[0076] The high entropy crystal / amorphous multilayer coating includes TaWMoCrZr layers and CrMoY layers that are alternately stacked. Since Ta, W, Mo, Cr, Zr, and Y elements are all insoluble in lead-bismuth alloys, and the TaWMoCrZr high entropy crystal monolayer has excellent thermal stability, and the CrMoY monolayer is a uniform amorphous structure. The TaWMoCrZr / CrMoY high entropy crystal / amorphous nano-multilayer coating designed based on this can effectively solve the problem that traditional nuclear reactor protective coatings are not resistant to lead-bismuth corrosion, and exhibits excellent mechanical properties and corrosion resistance. In addition, the crystal / amorphous nano-multilayer film can effectively capture irradiation defects due to the heterogeneous interface of the crystal / amorphous interface, and by selecting high-melting-point metal elements as high-entropy components, the refractory high-entropy alloy designed makes the high-entropy crystal / amorphous nano-multilayer coating have excellent thermal stability. Therefore, the new high-entropy crystal / amorphous multilayer coating with excellent comprehensive performance has the potential to become one of the choices for extreme environment service materials.

[0077] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A high entropy crystal / amorphous nanometal multilayer film, characterized in that: It includes TaWMoCrZr layers and CrMoY layers alternately stacked; The thickness of the TaWMoCrZr layer is 5-100 nm, and the thickness of the CrMoY layer is 1.25-25 nm; The TaWMoCrZr layer is in a nanocrystalline state, and the CrMoY layer is in an amorphous state.

2. A high entropy crystalline / amorphous nanometal multilayer film according to claim 1, characterized in that: The nano-indentation hardness of the nano-metal multilayer film is 9.5-10.5 GPa, and the Young's modulus is 161-174 GPa.

3. The high entropy crystalline / amorphous nanometal multilayer film according to claim 1, characterized in that: In the TaWMoCrZr layer, the atomic percentage ratio of the four elements Ta, W, Mo and Cr is 1:1:1:1, and the atomic percentage of the Zr element is 16.8 at.%.

4. The high entropy crystalline / amorphous nanometal multilayer film according to claim 1, characterized in that: The atomic percentage ratio of Cr, Mo and Y in the CrMoY layer is 1:1:

1.

5. A method for preparing a high entropy crystalline / amorphous nanometal multilayer film according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, cleaning and drying the substrate surface; Step 2, vacuum etching the substrate cleaned in step 1; Step 3, using a combination target of a TaWMoCr alloy target and a Zr target, and a TaWMoCr alloy target to alternately magnetron sputter deposit TaWMoCrZr crystal layers and TaWMoCr layers on a substrate to obtain a nano-metal multilayer film; During the magnetron sputtering process, the DC power of the TaWMoCr alloy target is 200 W, the RF power of the Zr target is 100 W, the DC power of the CrMoY alloy target is 200 W, and the total deposition time is 7496 to 9664 seconds; Step 4: Cool the nano-metal multilayer film to room temperature in the furnace to obtain a high entropy crystalline / amorphous nano-metal multilayer film.

6. The method for preparing a high entropy crystalline / amorphous nanometal multilayer film according to claim 5, characterized in that: The method of alternately depositing the TaWMoCrZr crystal layer and the TaWMoCr layer by magnetron sputtering in step 3 is as follows: Firstly, a TaWMoCrZr crystal layer is sputtered on a substrate using a combination target of a TaWMoCr alloy target and a Zr target; Then, a CrMoY amorphous layer is deposited by sputtering using a CrMoY alloy target; The above process is repeated, and TaWMoCrZr crystal layers and CrMoY amorphous layers are alternately deposited using a combined target and a CrMoY alloy target until the preset conditions are reached to obtain a nano-metal multilayer film.

7. The method for preparing a high entropy crystalline / amorphous nanometal multilayer film according to claim 5, characterized in that: The deposition gas pressure of the magnetron sputtering was set to 0.3 Pa, and the substrate rotation speed was 15 r / min.

8. The method for preparing a high entropy crystalline / amorphous nanometal multilayer film according to claim 5, characterized in that: The TaWMoCr alloy target and the CrMoY alloy target are both equiatomic targets.

9. The method for preparing a high entropy crystalline / amorphous nanometal multilayer film according to claim 5, characterized in that: The cooling time in step 4 is 2-3 hours.

10. An application of a high entropy crystalline / amorphous nanometal multilayer film prepared by the preparation method according to any one of claims 5 to 9, characterized in that: The nano metal multilayer film is applied to the lead-bismuth fast reactor cladding in a nuclear reactor.

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