Liquid lead bismuth corrosion resistant refractory high-entropy alloy, cladding material and preparation method thereof

Abstract

This invention belongs to the technical field of corrosion-resistant alloy materials, specifically disclosing a refractory high-entropy alloy resistant to liquid lead-bismuth corrosion, a cladding material, and its preparation method. The refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is composed of the following chemical elements: Nb 18–27 at.%; Mo 18–27 at.%; Ta 18–27 at.%; W 18–27 at.%; Cr 10–25 at.%; Si: 0–9 at.%; wherein the Si content is not zero. The cladding material is prepared by multi-target magnetron sputtering to prepare a refractory high-entropy alloy coating resistant to liquid lead-bismuth corrosion on the surface of a substrate. The doping of Cr and a small amount of Si in the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion of this invention promotes the formation of a protective continuous Cr₂O₃ layer, preventing direct contact between the liquid lead-bismuth alloy and the coating material, thereby significantly improving the coating's resistance to liquid lead-bismuth alloy corrosion.

Description

Technical Field

[0001] This invention relates to the field of corrosion-resistant alloy materials technology, specifically to refractory high-entropy alloys resistant to liquid lead-bismuth corrosion, cladding materials, and their preparation methods. Background Technology

[0002] The design blueprint for fourth-generation nuclear reactor systems indicates that increasing the reactor outlet temperature is a key factor in improving uranium thermal efficiency and utilization, especially given the high overall operating temperature of the reactor. Lead-bismuth alloys are chosen as coolant materials for fourth-generation nuclear reactors due to their advantages, including a low melting point (125℃), high boiling point (1670℃), good thermal conductivity, and inherent inertness in air. However, at high operating temperatures, lead-bismuth alloys can cause severe liquid metal corrosion of steel structural materials. This is primarily because metals with high (lead-bismuth) solubility, such as Fe, Ni, and Mn, in the steel gradually dissolve into the lead-bismuth alloy, leading to severe dissolution corrosion and liquid metal embrittlement of the structural materials. This significantly reduces the integrity and mechanical properties of the structural materials, thereby jeopardizing the safe operation of the reactor.

[0003] Currently, the main strategies for reducing lead-bismuth corrosion are structural material composition modification, oxygen concentration control, and surface coating technology. Among these, surface coating technology can improve the surface properties of structural materials without sacrificing other properties of the steel structure. Furthermore, the coating system can be designed and prepared relatively independently, without significantly affecting the processing and structural performance of existing fuel element cladding or core materials. Therefore, surface coating technology is considered internationally to be one of the most promising methods for solving the corrosion problem of lead-bismuth alloys on steel structures, and it is also the method most likely to be commercially viable in the short to medium term, making it highly competitive.

[0004] In recent years, high-entropy alloy coatings, a novel coating material system based on a novel design concept, have attracted significant attention from researchers both domestically and internationally due to their excellent comprehensive properties, including high-temperature stability, corrosion resistance, and radiation resistance. This is attributed to their thermodynamic high-entropy effect, structural lattice distortion effect, kinetic hysteresis diffusion effect, and performance-enhancing cocktail effect. However, several high-entropy alloy coating systems currently under study contain elements such as Fe and Al, which have high (lead-bismuth) solubility. Furthermore, when exposed to lead-bismuth at high temperatures and low oxygen levels, these elements still undergo severe dissolution corrosion. Therefore, exploring and developing high-entropy alloy coatings with excellent oxidation resistance and resistance to element dissolution remains a crucial research focus.

[0005] Existing literature reports that refractory metals such as Nb, Mo, Ta, and W exhibit extremely low dissolution rates in high-temperature lead-bismuth, effectively resisting the dissolution and corrosion of liquid lead-bismuth. Meanwhile, numerous studies have shown that due to the high (lead-bismuth) solubility and large atomic size of Al, Al-containing high-entropy alloy coatings struggle to form a protective continuous Al₂O₃ layer when exposed to lead-bismuth, resulting in poor oxidation resistance and resistance to elemental dissolution.

[0006] Therefore, it is necessary to provide refractory high-entropy alloys resistant to liquid lead-bismuth corrosion, cladding materials, and their preparation methods. This is of great significance. Summary of the Invention

[0007] To overcome the above defects, the present invention provides a refractory high-entropy alloy resistant to liquid lead-bismuth corrosion, a cladding material, and a method for preparing the same. Doping with Cr and a small amount of Si can promote the formation of a protective continuous Cr2O3 layer, preventing direct contact between the liquid lead-bismuth alloy and the coating material, thereby significantly improving the coating's resistance to liquid lead-bismuth alloy corrosion.

[0008] A refractory high-entropy alloy resistant to liquid lead-bismuth corrosion, composed of the following chemical elements:

[0009] Nb 18–27 at.%;

[0010] Mo 18–27 at.%;

[0011] Ta 18~27at.%;

[0012] W 18~27at.%;

[0013] Cr 10-25 at.%;

[0014] Si 0~9at.%;

[0015] The content of Si is not zero.

[0016] In one specific embodiment of the present invention, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion also includes unavoidable impurities. These unavoidable impurities do not include lead or bismuth.

[0017] In one specific embodiment of the present invention, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is composed of the following chemical elements:

[0018] Nb 20-24 at.%;

[0019] Mo 20-24 at.%;

[0020] Ta 20-24 at.%;

[0021] W 20-24 at.%;

[0022] Cr 15~22at.%;

[0023] Si 2~8.5at.%;

[0024] The content of Si is not zero.

[0025] In one specific embodiment of the present invention, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion also includes unavoidable impurities.

[0026] In one specific embodiment of the present invention, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion has a single body-centered cubic structure with no deposited phase precipitation.

[0027] In one specific embodiment of the present invention, the nanohardness of the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is ≥20 GPa.

[0028] In one specific embodiment of the present invention, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion has a single body-centered cubic structure after annealing at 650°C for 1000 hours.

[0029] The cladding material includes a substrate and a coating on the surface of the substrate, wherein the substrate is made of steel and the coating is the aforementioned refractory high-entropy alloy resistant to liquid lead-bismuth corrosion.

[0030] In one specific embodiment of the present invention, the shape of the substrate includes a tube, a plate, or a rod.

[0031] In one specific embodiment of the present invention, the steel is 12Cr iron horse steel.

[0032] In one specific embodiment of the present invention, using NbMoTaW alloy target, Cr target and Si target as target materials, a refractory high-entropy alloy coating resistant to liquid lead bismuth corrosion is prepared on the surface of the substrate based on a multi-target magnetron hybrid sputtering method.

[0033] In one specific embodiment of the present invention, the power of the NbMoTaW alloy target is 250-350W; the power of the Cr target is 80-130W; the power of the Si target is 20-50W; and the conditions for the multi-target magnetron hybrid sputtering method are: temperature 300-450℃, substrate bias voltage -120V--40V, vacuum position of 0.3-1Pa after filling with protective gas, holding at temperature for 2-5h after sputtering, and cooling at a rate of ≤100℃ / h after holding at temperature.

[0034] The above-mentioned application of refractory high-entropy alloys resistant to liquid lead-bismuth corrosion in the preparation of materials resistant to liquid lead-bismuth alloy corrosion.

[0035] The beneficial effects of this invention are:

[0036] 1. In this invention, Nb, Mo, Ta, and W provide the ability to suppress the occurrence of dissolution corrosion of the coating under high temperature or oxygen-deficient conditions. By adding appropriate amounts of Cr and Si elements, a dense, uniform, and continuous Cr2O3 layer can be formed in situ in the oxygen-rich liquid lead-bismuth alloy. This protective continuous Cr2O3 layer can effectively reduce the diffusion rate of alloying elements and simultaneously inhibit oxidation corrosion and dissolution corrosion of the material. In addition, by adding appropriate amounts of Si elements with small atomic size, the degree of lattice distortion of the coating can be increased and the grain size of the coating can be refined. Solid solution strengthening and grain refinement can further improve the mechanical properties of the coating. At the same time, the refinement of grain size can accelerate the growth of the protective continuous Cr2O3 layer, thereby further improving the coating's resistance to lead-bismuth corrosion.

[0037] 2. The refractory high-entropy alloy resistant to liquid lead-bismuth alloy corrosion proposed in this invention is a new alloy coating design scheme to solve the corrosion problem of structural materials in lead-cooled fast reactors. It can simultaneously meet the performance requirements of high strength, resistance to oxygen-deficient and oxygen-rich conditions of liquid lead-bismuth corrosion.

[0038] 3. The Nb, Mo, Ta, W, Cr and other metallic elements of the present invention have similar physical and chemical properties, and all have body-centered cubic structures. They are all high-melting-point metallic elements, thus they can impart better high-temperature strength, excellent high-temperature mechanical properties and structural stability to the coating.

[0039] 4. The coating made of the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion of the present invention can still maintain its original single body-centered cubic structure after annealing at 650℃ for 1000h, which has good high-temperature structural stability. This is beneficial for the long-term stable service of the coating in high-temperature lead-bismuth.

[0040] 5. The present invention can enhance the solid solution strengthening and grain refinement of the coating by appropriate Si doping. The nano-hardness of the refractory high entropy alloy coating resistant to liquid lead-bismuth corrosion is ≥20GPa, which is of high hardness. This is beneficial for the coating to resist fretting wear between structural materials and flow erosion of liquid lead-bismuth during service.

[0041] 6. The refractory metals Nb, Mo, Ta, and W selected in this invention have extremely low lead-bismuth solubility, which can suppress the dissolution corrosion of the coating material in lead-bismuth with low dissolved oxygen, at a dissolved oxygen concentration of 1×10⁻⁶. -8 No obvious elemental dissolution or lead-bismuth penetration was observed after exposure to liquid lead-bismuth at wt.% and 650℃ for 1000 hours, indicating excellent resistance to oxygen-deficient lead-bismuth corrosion.

[0042] 7. By adding Cr and Si elements, this invention enables the coating material to rapidly form a protective continuous Cr2O3 layer in lead-bismuth with high dissolved oxygen. This can inhibit further corrosion of the coating material by high-temperature liquid lead-bismuth, at a dissolved oxygen concentration of 1×10⁻⁶. -4 The oxide layer thickness detected after exposure to liquid lead bismuth at wt.% and 650℃ for 1000h was approximately 220nm, indicating excellent resistance to oxygen-rich lead bismuth corrosion.

[0043] 8. The refractory high-entropy alloy coating resistant to liquid lead-bismuth corrosion of the present invention has an alloy system that is easy to obtain and a simple and easy-to-operate preparation method. The magnetron sputtering process equipment used is all conventional equipment with low cost and good scalability, which makes it more valuable for application in the field of nuclear structural materials. Attached Figure Description

[0044] Figure 1 The X-ray diffraction patterns of the coated samples in Examples 1-4 of this invention are shown below.

[0045] Figure 2 The above are nano-hardness line graphs of the coating samples in Examples 1-4 of this invention.

[0046] Figure 3 These are X-ray diffraction patterns of the coating sample before and after annealing stability testing in Example 4 of this invention.

[0047] Figure 4 These are surface morphology images of the coated sample in Example 4 of the present invention before and after testing its resistance to low oxygen and liquid lead-bismuth.

[0048] Figure 5 This is a cross-sectional morphology diagram of the coating sample in Example 4 of the present invention after testing its resistance to low oxygen and liquid lead-bismuth.

[0049] Figure 6 This is an elemental distribution diagram of the coating sample in Example 4 of the present invention after testing its resistance to low oxygen and liquid lead-bismuth.

[0050] Figure 7 These are surface morphology images of the coating sample of Comparative Example 1 of the present invention before and after testing its resistance to low oxygen and liquid lead-bismuth.

[0051] Figure 8 This is a cross-sectional morphology diagram of the coating sample of Comparative Example 1 after testing its resistance to low oxygen and liquid lead-bismuth.

[0052] Figure 9 This is an elemental distribution diagram of the coating sample of Comparative Example 1 after testing its resistance to low oxygen and liquid lead-bismuth.

[0053] Figure 10 This is a cross-sectional morphology diagram of the coating sample in Example 4 of the present invention after testing its resistance to high oxygen and liquid lead-bismuth.

[0054] Figure 11 This is a cross-sectional morphology diagram of the coating sample of Comparative Example 1 after testing its resistance to high oxygen and liquid lead bismuth. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0056] The refractory high-entropy alloy resistant to liquid lead-bismuth corrosion provided by this invention is composed of the following chemical elements:

[0057] Nb 18–27 at.%;

[0058] Mo 18–27 at.%;

[0059] Ta 18~27at.%;

[0060] W 18~27at.%;

[0061] Cr 10-25 at.%;

[0062] Si 0~9at.%;

[0063] The content of Si is not zero.

[0064] The aforementioned refractory high-entropy alloys resistant to liquid lead-bismuth corrosion also include unavoidable impurities; these unavoidable impurities do not contain lead or bismuth.

[0065] In some instances, refractory high-entropy alloys resistant to liquid lead-bismuth corrosion are composed of the following chemical elements:

[0066] Nb 20-24 at.%;

[0067] Mo 20-24 at.%;

[0068] Ta 20-24 at.%;

[0069] W 20-24 at.%;

[0070] Cr 15~22at.%;

[0071] Si 2~8.5at.%;

[0072] The content of Si is not zero.

[0073] The aforementioned refractory high-entropy alloys resistant to liquid lead-bismuth corrosion also include unavoidable impurities; these unavoidable impurities do not contain lead or bismuth.

[0074] In some instances, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion has a single body-centered cubic structure with no deposited phase precipitation; the coatings made from the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion have uniform element distribution, thus preventing the precipitation of deposited phases.

[0075] In some instances, the nanohardness of the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is ≥20 GPa.

[0076] In some instances, the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion exhibits a single body-centered cubic structure after annealing at 650°C for 1000 hours.

[0077] The cladding material includes a substrate and a coating on the surface of the substrate, wherein the substrate is made of steel and the coating is the aforementioned refractory high-entropy alloy resistant to liquid lead-bismuth corrosion.

[0078] In some instances, the steel is 12Cr iron horse steel.

[0079] In some examples, using NbMoTaW alloy targets, Cr targets, and Si targets as targets, a multi-target magnetron hybrid sputtering method is used to prepare a refractory high-entropy alloy coating resistant to liquid lead-bismuth corrosion on the surface of the substrate.

[0080] In some instances, during multi-target magnetron hybrid sputtering, the content of each element in the coating is adjusted by regulating the sputtering power of the NbMoTaW alloy target, Cr target, and Si target.

[0081] In some examples, the power of the NbMoTaW alloy target is 250–350 W; the power of the Cr target is 80–130 W; the power of the Si target is 20–50 W; and the conditions for the multi-target magnetron hybrid sputtering method are: temperature 300–450 °C, substrate bias voltage -120 V to -40 V, vacuum position of 0.3–1 Pa after filling with protective gas, holding at the temperature for 2–5 h after sputtering, and cooling at a rate of ≤100 °C / h after holding at the temperature.

[0082] The above-mentioned application of refractory high-entropy alloys resistant to liquid lead-bismuth corrosion in the preparation of materials resistant to liquid lead-bismuth alloy corrosion.

[0083] To further illustrate the effect of the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion provided by the present invention in improving the corrosion resistance of liquid lead-bismuth alloys, the following examples and comparative examples are provided:

[0084] Example 1

[0085] This embodiment uses typical 12Cr iron horse steel for lead-cooled block stacking as the base material, and cuts the iron horse blocks into 10×5×2mm pieces using a telephone or cutting machine. 3 The substrate material is cut into small square pieces; then, SiC sandpaper is used to polish the small square pieces of substrate material. The sandpaper used for polishing is 180 grit, 400 grit, 600 grit, 1000 grit, 2000 grit and 3000 grit in sequence. Next, diamond polishing paste with a particle size of 1.5μm is used to finely polish the substrate material after polishing until the surface of the substrate material sample reaches a mirror finish. Finally, the polished substrate material is ultrasonically cleaned for 15 to 20 minutes using alcohol and acetone respectively.

[0086] NbMoTaW alloy targets, Cr targets, and Si targets are prepared using arc melting technology. The NbMoTaW alloy target is composed of Nb, Mo, Ta, and W in equal atomic percentages.

[0087] A refractory high-entropy alloy coating resistant to liquid lead-bismuth corrosion was prepared on the surface of a substrate material using a multi-target magnetron hybrid sputtering method. The polished substrate material was placed on the sample stage inside the vacuum chamber of the magnetron sputtering equipment, and the vacuum chamber was pre-evacuated to a pressure <1×10⁻⁶. -3 After sputtering at Pa, heating was initiated to raise the chamber temperature to 300℃. High-purity argon gas was then introduced into the chamber, maintaining the sputtering pressure at 0.5 Pa, the substrate bias at -50V, and the sputtering time at 2.5 h. Specific target parameters were: 300 W sputtering power for the NbMoTaW alloy target, 90 W sputtering power for the Cr target, and 20 W sputtering power for the Si target. A refractory high-entropy alloy coating with a specific composition, NbMoTaWCrSi, was obtained on the substrate material through multi-target co-sputtering. After sputtering, the substrate was held at room temperature for 2–5 h, followed by water cooling to room temperature, ensuring a cooling rate ≤100℃ / h. This yielded a cladding material with a refractory high-entropy alloy coating resistant to liquid lead-bismuth corrosion.

[0088] Example 2

[0089] The difference between this embodiment and Embodiment 1 is that the sputtering power of the Si target is 30W.

[0090] Example 3

[0091] The difference between this embodiment and Embodiment 1 is that the sputtering power of the Si target is 40W.

[0092] Example 4

[0093] The difference between this embodiment and Embodiment 1 is that the sputtering power of the Si target is 50W.

[0094] Comparative Example 1

[0095] The difference between this comparative example and Example 1 is that Si target material is not used.

[0096] Performance testing of cladding material:

[0097] I. Chemical Elemental Composition Analysis

[0098] 1. The chemical elemental composition of the refractory high-entropy alloy coatings resistant to liquid lead-bismuth corrosion obtained in Examples 1-4 was determined by X-ray photoelectron spectroscopy (XPS).

[0099] The statistical results of the chemical element content determination in Examples 1-4 are shown in the table.

[0100] Table 1

[0101]

[0102] 2. Lattice analysis of the coated samples

[0103] X-ray diffraction (XRD) analysis was performed on the coating samples of Examples 1-4 using an X-ray diffractometer.

[0104] The X-ray diffraction (XRD) analysis results of the coated samples in Examples 1-4 are as follows: Figure 1 As shown.

[0105] Depend on Figure 1 It can be seen that after removing the three weak diffraction peaks corresponding to the iron horse steel matrix material, only the diffraction peaks of the (110), (200), (211) and (220) crystal planes corresponding to the body-centered cubic structure were observed. This indicates that the NbMoTaWCrSi refractory high-entropy alloy coatings of the four embodiments are all composed of a single body-centered cubic phase structure, and no diffraction peak signals corresponding to other secondary phase precipitation were observed.

[0106] 3. Nanohardness test of coating samples

[0107] Nanohardness tests were performed on the coating samples of Examples 1-4 based on JB / T 12721-2016 "Technical Specification for In-situ Nanoindentation / Scratch Tester for Solid Materials".

[0108] The nanohardness test results of the coating samples in Examples 1-4 are as follows: Figure 2 As shown.

[0109] Depend on Figure 2As can be seen, the nanohardness of the coating samples in Examples 1-4 are 22.2 GPa, 23.9 GPa, 25.4 GPa and 26.9 GPa, respectively. The nanohardness of all four coating samples is >20 GPa, indicating that the refractory high-entropy alloy coating of the present invention, which is resistant to liquid lead-bismuth corrosion, has high hardness. Among them, the coating sample in Example 4 has the highest nanohardness, which is beneficial for the coating to resist fretting wear between structural materials and the flow erosion of liquid lead-bismuth during service.

[0110] 4. Annealing stability test of the coating sample in Example 4

[0111] The coating sample of Example 4 was annealed at 650°C for 1000 hours, and the annealed sample was analyzed by X-ray diffraction (XRD) using an X-ray diffractometer.

[0112] Example 4: X-ray diffraction (XRD) analysis results before and after annealing treatment are as follows: Figure 3 As shown.

[0113] Depend on Figure 3 As can be seen, the coating sample of Example 4 can still maintain its original single body-centered cubic (BCC) structure after annealing at 650°C for 1000 hours, indicating that the refractory high-entropy alloy coating provided by the present invention has good high-temperature structural stability, which is beneficial for the long-term stable service of the coating in high-temperature lead-bismuth.

[0114] 5. Oxygen resistance and liquid lead-bismuth resistance test of the coating sample in Example 4

[0115] ① The coating samples of Example 4 and Comparative Example 1 were subjected to a dissolved oxygen concentration of 1×10⁻⁶. -8 The coated samples were exposed to liquid lead bismuth at 650℃ for 1000 h at wt.% to analyze the surface morphology, cross-sectional morphology and elemental distribution.

[0116] Example 4: Surface morphology results of the coated sample before and after the test of its resistance to low oxygen and liquid lead bismuth are as follows. Figure 4 As shown.

[0117] Example 4: The cross-sectional morphology results of the coated sample after testing its resistance to low oxygen and liquid lead-bismuth are as follows. Figure 5 As shown.

[0118] Example 4: Elemental distribution results of the coated sample after testing its resistance to low oxygen and liquid lead-bismuth are as follows. Figure 6 As shown.

[0119] The surface morphology results of the coating sample in Comparative Example 1 before and after the test of its resistance to low oxygen and liquid lead bismuth are as follows: Figure 7 As shown.

[0120] The cross-sectional morphology results of the coating sample in Comparative Example 1 after testing its resistance to low oxygen and liquid lead-bismuth are as follows: Figure 8 As shown.

[0121] The elemental distribution results of the coating sample in Comparative Example 1 after testing its resistance to low oxygen and liquid lead-bismuth are as follows: Figure 9 As shown.

[0122] Depend on Figure 4-6 As can be seen, the coating sample of Example 4, at a dissolved oxygen concentration of 1×10⁻⁶, showed good performance. -8 After exposure to liquid lead-bismuth at 650°C for 1000 hours, the surface morphology of the coating was similar to that of the unexposed coating, except for some white lead-bismuth particles adhering to it; both consisted of some particle clusters. In addition, the cross-sectional morphology and elemental analysis results also showed that the coating elements did not undergo severe dissolution after exposure, the coating structure remained intact, and the constituent elements of the coating were roughly uniformly distributed along the cross-section. This indicates that the refractory high-entropy alloy coating of the present invention, which is resistant to liquid lead-bismuth corrosion, has excellent resistance to oxygen-deficient lead-bismuth corrosion.

[0123] Depend on Figure 7-9 As can be seen, the coating sample of Comparative Example 1, at a dissolved oxygen concentration of 1×10⁻⁶, showed better performance. -8 After exposure to liquid lead-bismuth at 650℃ for 1000 hours, a large number of chromium-rich oxide particles were precipitated on the surface. Cross-sectional line scanning showed that obvious chromium dissipation zones appeared on the surface of the coating after corrosion. These results indicate that the coating sample without added Si will experience more severe chromium consumption after exposure to oxygen-deficient lead-bismuth.

[0124] ② The coating samples of Example 4 and Comparative Example 1 were subjected to a dissolved oxygen concentration of 1×10⁻⁶. -4 The coated samples were exposed to liquid lead bismuth at 650℃ for 1000 h at wt.% for 1000 h, and the cross-sectional morphology and elemental distribution were analyzed.

[0125] Example 4: The cross-sectional morphology results of the coating sample's resistance to high oxygen and liquid lead-bismuth are as follows. Figure 10 As shown.

[0126] The elemental distribution results of the coating samples in Example 4, which tested their resistance to high oxygen and liquid lead-bismuth, are shown in Table 2.

[0127] Table 2

[0128]

[0129] The cross-sectional morphology results of the coating sample in Comparative Example 1, which tested its resistance to high oxygen and liquid lead bismuth, are as follows: Figure 11 As shown.

[0130] Depend on Figure 10-11 As shown in Table 2, the coating sample of Example 4 was tested at a dissolved oxygen concentration of 1×10⁻⁶.-4 After exposure to liquid lead-bismuth at 650℃ for 1000 hours (wt.%), the oxide layer formed after corrosion was approximately 220 nm thick. Scanning electron microscopy (EDS) elemental analysis showed that the oxide layer mainly contained O and Cr elements, with the ratio of O to Cr₂O₃ indicating that the refractory high-entropy alloy coating resistant to liquid lead-bismuth corrosion provided by this invention exhibits excellent resistance to oxygen-rich lead-bismuth corrosion. Comparative Example 1 coating sample was exposed to dissolved oxygen at a concentration of 1 × 10⁻⁶. -8 After exposure to liquid lead bismuth at wt.% and 650°C for 1000 h, an oxide film with a thickness of approximately 1100 nm was formed on the coating surface, which is 5 times thicker than the coating sample of Example 4 corroded under the same conditions.

Claims

1. A cladding material comprising a substrate and a coating on the surface of the substrate, characterized in that, The substrate is made of steel, and the coating is a refractory high-entropy alloy resistant to liquid lead-bismuth corrosion; the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is composed of the following chemical elements: Nb 18–27 at.%; Mo 18–27 at.%; Ta 18~27at.%; W 18~27at.%; Cr 10-25 at.%; Si: 0~9at.%; The content of Si is not zero; The preparation method of the cladding material includes the following steps: using NbMoTaW alloy target, Cr target and Si target as target materials, a refractory high entropy alloy coating resistant to liquid lead bismuth corrosion is prepared on the surface of the substrate based on the multi-target magnetron hybrid sputtering method; The refractory high-entropy alloy resistant to liquid lead-bismuth corrosion has a single body-centered cubic structure with no deposited phase precipitation. The nanohardness of the refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is ≥20 GPa.

2. The shell material according to claim 1, characterized in that, The refractory high-entropy alloy resistant to liquid lead-bismuth corrosion is composed of the following chemical elements: Nb 20-24 at.%; Mo 20-24 at.%; Ta 20-24 at.%; W 20-24 at.%; Cr 15~22at.%; Si 2~8.5at.%; The content of Si is not zero.

3. The cladding material of claim 1, wherein, The refractory high-entropy alloy resistant to liquid lead-bismuth corrosion has a single body-centered cubic structure after annealing at 650℃ for 1000 hours.

4. The cladding material of claim 1, wherein, The steel is 12Cr iron horse steel.

5. The cladding material of claim 1, wherein, The power of the NbMoTaW alloy target is 250-350W; the power of the Cr target is 80-130W; and the power of the Si target is 20-50W. The conditions for the multi-target magnetron hybrid sputtering method are: temperature 300-450℃, substrate bias voltage -120V--40V, vacuum position of 0.3-1Pa after filling with protective gas, heat preservation for 2-5h after sputtering, and cooling at ≤100℃ / h after heat preservation.

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