Novel nickel-based composite nanocrystalline coating and preparation method thereof

Abstract

The invention provides a novel nickel-based composite nanocrystalline coating and a preparation method thereof.The composite nanocrystalline coating comprises a Cr transition layer and a nickel-based coating, and the Cr transition layer and the nickel-based coating are both prepared in a magnetron sputtering mode; the Cr transition layer and the nickel-based coating deposited on the surface of the Cr transition layer form a deposition period, a plurality of deposition periods are sequentially stacked on the surface of the substrate, and the composite nanocrystalline coating is formed by the plurality of deposition periods; the single-layer thickness of the Cr transition layer is 1-3 [mu] m; the thickness of a single layer of the nickel-based coating is 2-15 microns; in the same deposition period, the thickness ratio of the Cr transition layer to the nickel-based coating is 1: 2-1: 5; and the total thickness of the composite nanocrystalline coating is 30-55 [mu] m. The preparation method has the technical effect that the thickness and the structural stability of the nanocrystalline coating are remarkably improved through collaborative optimization of the NiCrMoAl / Cr periodic gradient structure and multiple parameters.

Description

Technical Field

[0001] This invention belongs to the field of material surface modification technology, specifically relating to a novel nickel-based composite nanocrystalline coating and its preparation method. Background Technology

[0002] With the continuous development of industrial technology, the performance requirements for components are becoming increasingly stringent. Especially in the aerospace and marine fields, traditional coating materials may not be able to meet the application needs in certain extreme environments, thus necessitating the development of new coating materials and technologies. Taking IN718 nickel-based superalloy as an example, while traditional processes such as electroplating, thermal spraying, or laser cladding can improve oxidation resistance or wear resistance in the short term, the coating is prone to defects such as microcracks and pores (porosity > 8%), leading to insufficient interfacial bonding strength and a significantly shortened service life (< 500 hours).

[0003] The NiCrAlY coating prepared by laser cladding exhibits a 40% decrease in oxidation resistance after 200 hours under high-temperature cycling conditions (800℃) due to Kirkendal voids (average size 1.2μm) and γ' phase coarsening caused by element interdiffusion. In the prior art, patent CN10441821A employs a combination of magnetron sputtering and multi-arc ion plating. First, a sputtered nanocrystalline underlayer (20μm) is deposited on the alloy surface using magnetron sputtering, followed by the preparation of a NiCrAlY surface layer (10μm) using multi-arc ion plating. This overcomes the shortcomings of existing NiCrAlY coatings, such as easy interfacial element diffusion with the high-temperature substrate during high-temperature service and poor resistance to thermal cycling peeling of the surface oxide film. While this technology improves the coating's resistance to high-temperature element diffusion, it still has significant drawbacks. The process is highly complex, requiring the switching between two deposition equipment. The interlayer interface is easily contaminated (oxygen content increases by 0.5-1.2 at.%), and it can also cause thermal stress accumulation. The difference in thermal expansion coefficients between heterogeneous coatings leads to high residual stress after thermal cycling at 800℃. The structural uniformity increases the risk of crack propagation along the hard / soft interface.

[0004] Traditional nickel-based coatings are mostly applied using methods such as spraying and laser cladding. However, these methods often struggle to achieve both high coating thickness and uniformity simultaneously. Due to the inherent stress of the coating, cracking and peeling are common problems. Moreover, the high-temperature corrosion resistance and oxidation resistance of traditional coating materials often fail to meet the demands of modern high-temperature environments, especially in gas turbine engines or other extreme conditions, where such coatings are prone to failure.

[0005] To overcome these shortcomings, nickel-based nanocrystalline coatings have emerged. Due to their small grain size, nanocrystalline materials typically exhibit higher hardness, stronger wear resistance, and better thermal stability, making them suitable for engineering applications in complex environments. However, traditional nickel-based nanocrystalline coatings are generally thin, mostly within 10 μm. As the thickness increases, the internal stress of the coating becomes greater, easily leading to problems such as cracking and peeling, affecting its long-term engineering protective performance. Therefore, the thickness of nickel-based nanocrystalline coatings is limited. Summary of the Invention

[0006] The present invention aims to at least solve one of the technical problems existing in the prior art, and to provide a new technical solution for a novel nickel-based composite nanocrystalline coating and its preparation method.

[0007] According to a first aspect of the present invention, a novel nickel-based composite nanocrystalline coating is provided, comprising a Cr transition layer and a nickel-based coating, wherein both the Cr transition layer and the nickel-based coating are prepared by magnetron sputtering.

[0008] The Cr transition layer and the nickel-based coating deposited on the surface of the Cr transition layer constitute a deposition cycle, and multiple deposition cycles are sequentially stacked on the surface of the substrate, forming a composite nanocrystalline coating.

[0009] The thickness of the single layer of the Cr transition layer is 1-3 μm; the thickness of the single layer of the nickel-based coating is 2-15 μm.

[0010] Within the same deposition cycle, the thickness ratio of the Cr transition layer to the nickel-based coating is 1:2 to 1:5;

[0011] The total thickness of the composite nanocrystalline coating is 30–55 μm.

[0012] Optionally, the substrate material is at least one of IN718 high-temperature alloy, stainless steel, and silicon wafer.

[0013] According to a second aspect of the present invention, a method for preparing a novel nickel-based composite nanocrystalline coating is provided, for preparing the novel nickel-based composite nanocrystalline coating as described in the first aspect, comprising the following steps:

[0014] Step S1: Pre-treat the substrate, place the pre-treated substrate into the coating chamber of the magnetron sputtering equipment and fix it on the sample holder;

[0015] Step S2: Evacuate the coating chamber to a preset vacuum level and heat the coating chamber to a preset temperature;

[0016] Step S3: Argon gas is introduced into the coating chamber, and the substrate surface is cleaned by ion beam.

[0017] Step S4: In the coating chamber, the Cr target and the NiCrMoAl target are pre-sputtered sequentially.

[0018] Step S5: First, sputter the Cr target to deposit a Cr transition layer; then sputter the NiCrMoAl target to deposit a nickel-based coating.

[0019] Step S6, repeat step S5 to obtain a composite nanocrystalline coating; wherein, sputtering deposition is performed according to a preset period and a preset thickness ratio of the Cr transition layer to the nickel-based coating.

[0020] Optionally, in step S1, the substrate is pretreated, including:

[0021] The substrate is ultrasonically cleaned using a detergent, and then dried after ultrasonic cleaning; wherein the detergent is at least one of acetone or ethanol.

[0022] Optionally, the ultrasonic cleaning process takes 10 to 25 minutes, the drying time takes 0.5 to 1.5 hours, and the drying temperature takes 50 to 60°C.

[0023] Optionally, when performing ion beam cleaning on the substrate surface, the ion beam voltage is 800V-1600V; the deflection voltage is -100V to -800V.

[0024] Optionally, when sputtering the Cr target, the target-substrate distance is 100-220 mm, the sputtering current is 1-3 A, and the argon gas flow rate during sputtering is 15-45 sccm.

[0025] Optionally, when sputtering the NiCrMoAl target, the target-substrate distance of the sputtered NiCrMoAl target is 100-220 mm; the power of sputtering the NiCrMoAl target is 1-5 A; and the flow rate of argon gas introduced when sputtering the NiCrMoAl target is 15-45 sccm.

[0026] Optionally, in step S5, the deposition temperature is 100–400°C.

[0027] Optionally, in step S4, the pre-sputtering time is 3-5 minutes.

[0028] One technical advantage of this invention is that:

[0029] In this embodiment, a novel NiCrMoAl composite nanocrystalline coating is prepared on a substrate surface using magnetron sputtering. A Cr transition layer is used in each deposition cycle. The Cr transition layer can alleviate stress, achieving a low-stress, strong-bonded composite nanocrystalline coating with a thickness of 30-55 μm. Simultaneously, through the periodic gradient structure of NiCrMoAl / Cr and multi-parameter synergistic optimization, the causal chain in the background technology is fundamentally blocked, significantly improving the thickness and structural stability of the nanocrystalline coating.

[0030] Moreover, the composite nanocrystalline coating of this application can overcome the problems of stress concentration, low interfacial bonding strength, and high brittleness of existing nickel-based coatings, and has the advantages of high thickness, low stress, and excellent interfacial bonding performance. In addition, the preparation method of this novel nickel-based composite nanocrystalline coating achieves a synergistic improvement in long life and high reliability of the composite nanocrystalline coating while ensuring process simplicity. Attached Figure Description

[0031] Figure 1 This is a schematic flowchart illustrating a method for preparing a novel nickel-based composite nanocrystalline coating according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the structure of a novel nickel-based composite nanocrystalline coating according to an embodiment of the present invention;

[0033] Figure 3 This is a cross-sectional SEM image of a novel nickel-based composite nanocrystalline coating according to an embodiment of the present invention;

[0034] Figure 4 These are schematic diagrams illustrating the bonding force between the novel nickel-based composite nanocrystalline coating and the substrate in different embodiments of the present invention.

[0035] Figure 5 This is a SEM image of the surface of a novel nickel-based composite nanocrystalline coating after high-temperature heat treatment, according to an embodiment of the present invention.

[0036] In the figure: 1. Substrate; 2. Cr transition layer; 3. Nickel-based coating. Detailed Implementation

[0037] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0038] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0039] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0040] According to a first aspect of the invention, see Figure 2 and Figure 3 This invention provides a novel nickel-based composite nanocrystalline coating that can solve the problems of thin thickness, high internal stress, and insufficient engineering protection performance of existing nickel-based nanocrystalline coatings under high temperature environments.

[0041] Specifically, the novel nickel-based composite nanocrystalline coating includes a Cr transition layer 2 and a nickel-based coating 3, and both the Cr transition layer 2 and the nickel-based coating 3 (i.e., the NiCrMoAl layer) are prepared by magnetron sputtering; wherein, the NiCrMoAl layer is a functional layer.

[0042] The Cr transition layer 2 and the nickel-based coating 3 deposited on the surface of the Cr transition layer 2 constitute a deposition cycle, and multiple deposition cycles are sequentially stacked on the surface of the substrate 1, forming a composite nanocrystalline coating.

[0043] The thickness of a single Cr transition layer 2 is 1–3 μm; the thickness of a single nickel-based coating 3 is 2–15 μm.

[0044] Within the same deposition cycle, the thickness ratio of the Cr transition layer 2 to the nickel-based coating 3 is 1:2 to 1:5;

[0045] The total thickness of the composite nanocrystalline coating is 30–55 μm.

[0046] In this embodiment, a novel NiCrMoAl composite nanocrystalline coating is prepared on a substrate surface using magnetron sputtering. A Cr transition layer is used in each deposition cycle. The Cr transition layer can alleviate stress, achieving a low-stress, strong-bonded composite nanocrystalline coating with a thickness of 30-55 μm. Simultaneously, through the periodic gradient structure of NiCrMoAl / Cr and multi-parameter synergistic optimization, the causal chain in the background technology is fundamentally blocked, significantly improving the thickness and structural stability of the nanocrystalline coating.

[0047] Moreover, the composite nanocrystalline coating of this application can overcome the problems of stress concentration, low interfacial bonding strength, and high brittleness of existing nickel-based coatings, and has the advantages of high thickness, low stress, and excellent interfacial bonding performance. In addition, the preparation method of this novel nickel-based composite nanocrystalline coating achieves a synergistic improvement in long life and high reliability of the composite nanocrystalline coating while ensuring process simplicity.

[0048] Optionally, the substrate material is at least one of IN718 high-temperature alloy, stainless steel, and silicon wafer. This helps to form a composite nanocrystalline coating with high thickness, low stress, and good interfacial bonding performance on the substrate surface.

[0049] According to a second aspect of the invention, see Figure 1 A novel method for preparing a nickel-based composite nanocrystalline coating is provided, which is used to prepare the novel nickel-based composite nanocrystalline coating as described in the first aspect.

[0050] Specifically, the preparation method of this novel nickel-based composite nanocrystalline coating includes the following steps:

[0051] Step S1: Pre-treat the substrate, place the pre-treated substrate into the coating chamber of the magnetron sputtering equipment and fix it on the sample holder;

[0052] Step S2: Evacuate the coating chamber to a preset vacuum level and heat the coating chamber to a preset temperature;

[0053] Step S3: Argon gas is introduced into the coating chamber, and the substrate surface is cleaned by ion beam.

[0054] Step S4: In the coating chamber, the Cr target and the NiCrMoAl target are pre-sputtered sequentially.

[0055] Step S5: First, sputter the Cr target to deposit a Cr transition layer; then sputter the NiCrMoAl target to deposit a nickel-based coating.

[0056] Step S6, repeat step S5 to obtain a composite nanocrystalline coating; wherein, sputtering deposition is performed according to a preset period and a preset thickness ratio of the Cr transition layer to the nickel-based coating.

[0057] In the above embodiments, the preparation method of this novel nickel-based composite nanocrystalline coating specifically employs DC magnetron sputtering technology to prepare a high-thickness, low-stress NiCrMoAl / Cr gradient structure nanocrystalline coating. This method, through multi-layer gradient structure design and process parameter optimization, achieves the characteristics of high thickness, low stress, and strong adhesion in the nickel-based coating, making it suitable for the protection of critical components in high-temperature, corrosive, and high-stress environments in aerospace, marine engineering, and chemical equipment.

[0058] Optionally, in step S1, the substrate is pretreated, including:

[0059] The substrate is ultrasonically cleaned using a detergent, and then dried. The detergent is at least one of acetone or ethanol. This helps ensure the cleanliness of the substrate surface.

[0060] Optionally, the ultrasonic cleaning process involves a washing time of 10–25 minutes and a drying time of 0.5–1.5 hours, with a drying temperature of 50–60°C. This ensures the effectiveness of the ultrasonic cleaning, effectively removing dirt and impurities from the substrate surface to guarantee the adhesion and surface quality of the composite nanocrystalline coating.

[0061] Optionally, when performing ion beam cleaning on the substrate surface, the ion beam voltage is 800V-1600V; the deflection voltage is -100V to -800V; and the time is 10-60 minutes. This ensures a good cleaning effect, removing surface contaminants through physical sputtering by bombarding the workpiece surface (i.e., the substrate surface) with a high-energy ion beam. Ion beam cleaning not only effectively removes impurities such as grease and oxides but also improves the surface properties of materials to a certain extent. Compared with traditional cleaning methods, ion beam cleaning has advantages such as being non-contact, highly efficient, highly clean, and environmentally friendly.

[0062] Optionally, when sputtering the Cr target, the target-to-substrate distance is 100–220 mm, the sputtering current is 1–3 A, and the argon gas flow rate during sputtering is 15–45 sccm. The bias voltage of the Cr target is -100 to -800 V.

[0063] In the above embodiments, the sputtering deposition effect of the Cr transition layer can be well guaranteed.

[0064] Optionally, when sputtering the NiCrMoAl target, the target-substrate distance is 100–220 mm; the sputtering power of the NiCrMoAl target is 1–5 A; the argon gas flow rate introduced during sputtering of the NiCrMoAl target is 15–45 sccm; and the bias voltage of the NiCrMoAl target is -100 to -800 V.

[0065] In the above embodiments, the sputtering deposition effect of the nickel-based coating (i.e., the NiCrMoAl layer) can be well guaranteed.

[0066] Optionally, in step S5, the deposition temperature is 100–400°C. This makes the deposition temperature suitable and better ensures the deposition effect.

[0067] Optionally, in step S4, the pre-sputtering time is 3-5 minutes. Pre-sputtering can effectively remove impurities, oxide layers, and other contaminants from the target surface, thus laying a good foundation for subsequent high-quality thin film deposition.

[0068] For example, the pressure in the coating chamber after evacuation is less than 9 × 10⁻⁶. -3 Pa, for example, the pressure in the coating chamber after evacuation is 3 × 10 Pa. -3 ~7×10 -3 Pa. This can significantly improve multiple aspects of the coating process, including but not limited to film purity, uniformity, adhesion, and overall process controllability and stability. This is crucial for applications that demand high-quality, high-performance films.

[0069] In one specific embodiment, both the NiCrMoAl target and the Cr target are rectangular targets with a purity of 99.9%. The deposition time for the Cr target is 1–3 hours, and the deposition time for the NiCrMoAl target is 3–8 hours.

[0070] It should be noted that magnetron sputtering is a type of physical vapor deposition (PVD). Compared with other technologies, it offers advantages such as ease of operation, fast film formation rate, low substrate temperature, strong film-substrate adhesion, and the ability to achieve large-area coatings. Coatings prepared using magnetron sputtering exhibit uniform composition, good process repeatability, high density and precision, and low porosity. Furthermore, they maintain a high degree of consistency with the substrate in terms of stress and thermal expansion, reducing stress concentration and crack formation within the coating. Therefore, magnetron sputtering is the most widely used technology for preparing nanocrystalline coatings. Metal nanocrystalline coatings exhibit significant advantages due to their unique microstructure. Because of their extremely small grain size, nanocrystalline coatings typically possess high hardness and wear resistance, effectively reducing friction and wear, and extending the coating's service life. In addition, the nanocrystalline structure enhances the coating's corrosion resistance, fatigue resistance, and creep resistance, maintaining good performance, especially under high-temperature environments. The coating exhibits strong adhesion and bonding with the substrate, adapting to high-load and thermal stress working conditions. Furthermore, nanocrystalline coatings also possess good impact resistance, effectively dispersing stress and preventing crack formation. Therefore, metal nanocrystalline coatings have shown great application potential in many demanding application fields, such as aerospace, automotive and mechanical engineering.

[0071] In this embodiment, the composite nanocrystalline coating is prepared on the surface of IN718 alloy using DC magnetron sputtering technology. Through gradient structure design and synergistic optimization of process parameters, a high-thickness, low-stress NiCrMoAl / Cr gradient structure nanocrystalline coating is fabricated. Specifically, a periodic stress-relieving structure is constructed by alternately depositing a Cr transition layer (1-3 μm) and a NiCrMoAl functional layer (2-15 μm), reducing the residual stress of the coating while maintaining high bonding strength and high-temperature stability.

[0072] Example 1

[0073] In this embodiment, the main preparation steps of the novel nickel-based composite nanocrystalline coating are as follows:

[0074] First, NiCrMoAl alloy targets with a purity higher than 99.9% and pure Cr targets are selected to ensure that the target surface is smooth and free of cracks and impurities. A magnetron sputtering coating machine equipped with a high-purity inert gas supply system, a target replacement device, and a substrate heating device is used. At the same time, it is ensured that there is no oil or impurities in the sputtering chamber, and that the walls of the deposition chamber and the target surface are clean.

[0075] Then, select a suitable substrate material, such as IN718 high-temperature alloy, 304 stainless steel or Si sheet, polish its surface to reduce roughness, and use ethanol to ultrasonically clean it to remove surface dirt and impurities to ensure coating adhesion and surface quality.

[0076] Next, the cleaned substrate material was fixed on the sample holder of the magnetron sputtering equipment, with a target-substrate spacing of 150 mm; a vacuum was then drawn until the pressure was below 7 × 10⁻⁶. -3 Pa. Raise the temperature to 300°C and maintain it.

[0077] Next, the ion beam voltage was set to 1300V, and high-purity argon gas was introduced as the sputtering gas, with a flow rate controlled at 30 sccm. Ion beam cleaning was then performed on the substrate surface. The high-energy ion beam bombarded the workpiece surface, removing surface contaminants through a physical sputtering effect. This method not only effectively removes impurities such as grease and oxides but also improves the surface properties of materials to a certain extent. Compared with traditional cleaning methods, ion beam cleaning has advantages such as being non-contact, highly efficient, achieving high cleanliness, and being environmentally friendly.

[0078] Finally, the parameters for the Cr target and the NiCrMoAl target (i.e., the nickel-based target) are set as shown in Table 1. When the composite nanocrystalline coating deposition is complete, refer to... Figure 3 The total thickness reaches 35 μm, exhibiting excellent interfacial bonding performance. Therefore, the novel nickel-based composite nanocrystalline coating provided in this application has the advantages of high thickness and excellent interfacial bonding performance.

[0079] Table 1 shows the process parameter settings for preparing the NiCrMoAl / Cr composite nanocrystalline coating.

[0080]

[0081] Example 2

[0082] Example 2 is basically the same as Example 1, and the similarities will not be repeated here. In Example 2, the deflection voltage in each step is changed when setting the process parameters. The specific parameter settings are detailed in Table 2.

[0083] Table 2 shows the process parameter settings for preparing the NiCrMoAl / Cr composite nanocrystalline coating.

[0084]

[0085] Example 3

[0086] Example 3 is basically the same as Example 1, and the similarities will not be repeated here. In Example 3, the gas flow rate in each step is changed when setting the process parameters. The specific parameter settings are detailed in Table 3.

[0087] Table 3 shows the process parameter settings for preparing the NiCrMoAl / Cr composite nanocrystalline coating.

[0088]

[0089] Example 4

[0090] Example 4 is basically the same as Example 1, and the similarities will not be repeated here. In Example 4, the deposition temperature is changed in each step when setting the process parameters. The specific parameter settings are detailed in Table 4.

[0091] Table 4 shows the process parameter settings for preparing the NiCrMoAl / Cr composite nanocrystalline coating.

[0092]

[0093] Example 5

[0094] Example 5 is basically the same as Example 1, and the similarities will not be repeated here. In Example 5, the coating cycle in each step is changed when setting the process parameters. The specific parameter settings are detailed in Table 5.

[0095] Table 5. Preparation process parameters of NiCrMoAl / Cr composite nanocrystalline coating

[0096]

[0097] Comparative Example 1

[0098] In Comparative Example 1, the transition layer was changed to an Al layer when setting the process parameters. For details of the parameter settings, please refer to Table 6.

[0099] Table 6. Preparation process parameters of NiCrMoAl / Al composite nanocrystalline coating

[0100]

[0101] The bonding strength between the composite nanocrystalline coatings and the substrate in Examples 1-5 and Comparative Example 1 is as follows: Figure 4 As shown, by Figure 4 It can be seen that the prepared composite nanocrystalline coating has high bonding strength and excellent interfacial bonding performance.

[0102] Figure 5 The image shows a SEM image of the nickel-based composite nanocrystalline coating after high-temperature treatment. It can be seen that the prepared composite nanocrystalline coating did not crack or peel off after high-temperature treatment, indicating that the coating has a good stable structure.

[0103] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A novel nickel-based composite nanocrystalline coating, characterized in that, It includes a Cr transition layer and a nickel-based coating, and both the Cr transition layer and the nickel-based coating are prepared by magnetron sputtering; The Cr transition layer and the nickel-based coating deposited on the surface of the Cr transition layer constitute a deposition cycle, and multiple deposition cycles are sequentially stacked on the surface of the substrate, forming a composite nanocrystalline coating. The thickness of the single layer of the Cr transition layer is 1-3 μm; the thickness of the single layer of the nickel-based coating is 2-15 μm. Within the same deposition cycle, the thickness ratio of the Cr transition layer to the nickel-based coating is 1:2 to 1:5; The total thickness of the composite nanocrystalline coating is 30–55 μm.

2. The novel nickel-based composite nanocrystalline coating according to claim 1, characterized in that, The substrate material is at least one of IN718 high-temperature alloy, stainless steel, and silicon wafer.

3. A method for preparing a novel nickel-based composite nanocrystalline coating, characterized in that, The method for preparing the novel nickel-based composite nanocrystalline coating as described in any one of claims 1 to 2 comprises the following steps: Step S1: Pre-treat the substrate, place the pre-treated substrate into the coating chamber of the magnetron sputtering equipment and fix it on the sample holder; Step S2: Evacuate the coating chamber to a preset vacuum level and heat the coating chamber to a preset temperature; Step S3: Argon gas is introduced into the coating chamber, and the substrate surface is cleaned by ion beam. Step S4: In the coating chamber, the Cr target and the NiCrMoAl target are pre-sputtered sequentially. Step S5: First, sputter the Cr target to deposit a Cr transition layer; then sputter the NiCrMoAl target to deposit a nickel-based coating. Step S6, repeat step S5 to obtain a composite nanocrystalline coating; wherein, sputtering deposition is performed according to a preset period and a preset thickness ratio of the Cr transition layer to the nickel-based coating.

4. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 3, characterized in that, In step S1, the substrate is pretreated, including: The substrate is ultrasonically cleaned using a detergent, and then dried after ultrasonic cleaning; wherein the detergent is at least one of acetone or ethanol.

5. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 4, characterized in that, The ultrasonic cleaning process involves a washing time of 10–25 min, a drying time of 0.5–1.5 h, and a drying temperature of 50–60 °C.

6. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 3, characterized in that, When performing ion beam cleaning on the substrate surface, the ion beam voltage is 800V-1600V; the deflection voltage is -100V to -800V.

7. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 3, characterized in that, When sputtering a Cr target, the target-to-substrate distance is 100–220 mm, the sputtering current is 1–3 A, and the argon gas flow rate during sputtering is 15–45 sccm.

8. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 3, characterized in that, When sputtering a NiCrMoAl target, the target-substrate distance is 100–220 mm; the sputtering power is 1–5 A; and the argon gas flow rate is 15–45 sccm.

9. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 3, characterized in that, In step S5, the deposition temperature is 100–400°C.

10. The method for preparing the novel nickel-based composite nanocrystalline coating according to claim 3, characterized in that, In step S4, the pre-sputtering time is 3-5 minutes.

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