A high-entropy nanocomposite film with self-supporting properties and preparation method thereof

Abstract

The present invention provides a self-supporting high-entropy nanocomposite film and its preparation method. The preparation method comprises the following steps: using a high-power pulsed magnetron sputtering method, splicing together metal strips of four elements, Fe, Co, Ni, and Cr, as a sputtering target, using high-purity Ar and a carbon-containing source gas as working gases, applying a negative bias voltage to a substrate after surface cleaning, and applying a target voltage to the metal spliced ​​target to deposit the high-entropy nanocomposite film; after the high-entropy nanocomposite film is deposited, it is cooled to below 80°C in a vacuum environment, vented, opened the cavity, and removed from the furnace, thereby obtaining a self-supporting high-entropy nanocomposite film on the substrate surface. The film comprises, in atomic percentage, 5-35 at.% of each of the four metals, Fe, Co, Ni, and Cr, and 10-40 at.% of carbon, with the sum of the atomic percentages of these components being 100%. Through compositional design and process innovation, the present invention achieves the synergistic optimization of high hardness, high toughness, corrosion resistance, and self-supporting performance.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film materials, and in particular to a high-entropy nanocomposite film with self-supporting properties and a preparation method thereof. Background Art

[0002] With the rapid development of flexible electronics, biomedicine, and extreme environment protection, self-supporting films have attracted much attention due to their independent characteristics that do not require substrate support. However, existing technologies are mostly limited to pure metal or low non-metal alloy systems. Such self-supporting films are limited by insufficient mechanical properties and corrosion resistance, making it difficult to meet the needs of complex scenarios. For example, AlCrNiTiV metal films deposited by cathode vacuum arc or FeCoNiCu and Bi-Sn films prepared by magnetron sputtering can achieve self-supporting characteristics, but they lack toughness, have limited corrosion resistance, and have a single function. Pure metal films are prone to crack propagation due to dislocation accumulation when bent or stretched, leading to fracture; and in acidic or high-temperature corrosive environments, metal films are prone to oxidation or pitting, which seriously limits their application scenarios.

[0003] In addition, although the introduction of non-metallic elements (such as carbon and nitrogen) can improve the hardness, the failure rate of peeling of traditional alloy films increases due to increased brittleness when the carbon or nitrogen content is high, making it difficult to strike a balance between strength and flexibility. For example, high-entropy alloy films have shown great potential in flexible electronics, biomedicine, catalytic energy storage, extreme protection and other fields due to their high hardness, high toughness, corrosion resistance and versatility. However, traditional high-entropy alloy films usually rely on substrate support, and the introduction of non-metallic elements (such as carbon and boron) often increases brittleness due to internal stress concentration or insufficient interfacial bonding force, making it difficult to peel off as an independent film. Therefore, it is of great significance to develop thin film materials with both high mechanical properties and self-supporting characteristics. Summary of the Invention

[0004] Based on the above background technology, an object of the present invention is to provide a method for preparing a high-entropy nanocomposite film with self-supporting properties; another object of the present invention is to provide a high-entropy nanocomposite film with self-supporting properties.

[0005] The present invention adopts the following technical solutions:

[0006] As one of the purposes, a method for preparing a high entropy nanocomposite film with self-supporting properties comprises the following steps:

[0007] High-power pulsed magnetron sputtering was used, with metal strips of four elements, Fe, Co, Ni, and Cr, spliced ​​together as sputtering targets. High-purity Ar and carbon-containing gas were used as working gases. A negative bias was applied to the surface-cleaned substrate, and a target voltage was applied to the metal spliced ​​target to deposit high-entropy nanocomposite films.

[0008] After the high entropy nanocomposite film is deposited, it is cooled in a vacuum environment, and then the air is released and the cavity is opened and the furnace is taken out, so that a high entropy nanocomposite film with self-supporting properties is obtained on the surface of the substrate.

[0009] Preferably, after the high entropy nanocomposite film is deposited, it is cooled to below 100° C. in a vacuum environment.

[0010] Furthermore, the metal spliced ​​target is a spliced ​​target formed by periodically arranging metal strip targets of four elements, Fe, Co, Ni, and Cr.

[0011] In the above technical solution, high-power pulsed magnetron sputtering technology (HiPIMS) is adopted, and metal strips of four elements, Fe, Co, Ni, and Cr, are spliced ​​together as sputtering targets. The metal composition in the film is precisely controlled by adjusting the number and arrangement of each metal strip in the spliced ​​target. High-purity Ar and carbon-containing gas source are used as working gases, a negative bias is applied to the substrate after surface cleaning, and a target voltage is applied to the metal spliced ​​target. During the deposition process, the C ions obtained by dissociation of the carbon-containing gas source react with part of the Cr to obtain an amorphous chromium carbide ceramic phase, and the remaining Cr dissolves with Fe, Co, and Ni elements to form a high-entropy alloy phase. The excess C element forms a graphite phase under the catalytic action of the metal, thereby obtaining a multiphase nanocomposite structure film composed of a face-centered cubic high-entropy alloy phase, an amorphous chromium carbide ceramic phase, and a graphite phase.

[0012] Furthermore, the substrate bias voltage is -100V to 0V; the sputtering power of the metal splicing target is 4 to 8W / cm 2 The working gas Ar flow rate is 10 to 90 sccm, and the gas pressure in the chamber is maintained at 0.2 to 2.0 Pa during the sputtering coating process; the deposition time is 20 to 80 minutes.

[0013] Furthermore, the carbon-containing gas source is acetylene or methane.

[0014] Furthermore, the carbon-containing gas source is acetylene, and the acetylene flow rate is 1 to 4 sccm.

[0015] During the deposition process, the precipitation ratio and morphology of the high-entropy alloy phase, amorphous chromium carbide ceramic phase and graphite phase are controlled by controlling the metal splicing target sputtering power, acetylene flow rate and bias voltage, thereby obtaining a high-entropy film with excellent comprehensive mechanical properties.

[0016] Furthermore, the substrate is an aluminum alloy or a silicon substrate.

[0017] Furthermore, the method also includes selectively corroding an aluminum substrate with hydrochloric acid or mechanically peeling off a silicon substrate to obtain a self-supporting high entropy nanocomposite film.

[0018] Preferably, the chamber is evacuated to 1×10-3 Pa~5×10 -3 Pa.

[0019] Preferably, the purity of the four metals in the spliced ​​target is ≥99.8%.

[0020] Preferably, the purity of the argon gas and the carbon-containing source gas is ≥99.9%.

[0021] Preferably, the substrate is not artificially heated during deposition.

[0022] Furthermore, the surface cleaning treatment of the substrate includes one or more of ultrasonic cleaning and plasma glow discharge sputtering cleaning;

[0023] Plasma glow discharge cleaning refers to placing the substrate into the cavity of the magnetron sputtering equipment, and the cavity background vacuum is pumped to 1×10 -3 Pa~5×10 -3 Pa, and then high-purity Ar is introduced into the cavity, the pressure in the cavity is adjusted to 3-4 Pa, a negative bias of -1500 V is applied to the substrate, and Ar plasma is generated near the substrate. The Ar in the plasma + Bias reverse sputtering cleaning is performed by bombarding the substrate under negative bias voltage.

[0024] Preferably, during plasma glow discharge cleaning, the Ar flow rate is 20 to 60 sccm; and the sputtering cleaning time is 10 to 30 minutes.

[0025] Preferably, during plasma glow discharge cleaning, the chamber temperature is 0-350°C.

[0026] As another purpose, a high-entropy nano-composite film with self-supporting properties is provided. The composition of the high-entropy nano-composite film with self-supporting properties is as follows in atomic percentage: Fe, Co, Ni, Cr, four metals are 5 to 35 at.%, respectively, carbon atoms are 10 to 40 at.%, and the sum of the atomic percentages of the above components is 100%.

[0027] Furthermore, the thickness of the high entropy nanocomposite film with self-supporting properties is 1-5 μm.

[0028] In this technical solution, a self-supporting high-entropy nanocomposite film is obtained by selectively etching an aluminum substrate with hydrochloric acid or mechanically exfoliating a silicon substrate. The film thickness is controlled within the 1-5 μm range. Too thin can lead to insufficient mechanical properties, while too thick can affect flexibility.

[0029] Compared with the prior art, the present invention is beneficial in that:

[0030] This paper successfully fabricates FeCoNiCrC high-entropy alloy thin films with high mechanical properties, corrosion resistance, and self-supporting properties through high-power pulsed magnetron sputtering (HiPIMS) technology and multiphase nanocomposite structure design. Its beneficial effects are reflected in the following aspects:

[0031] 1. Multiphase synergistic enhancement of mechanical and corrosion resistance

[0032] (1) Face-centered cubic (FCC) high entropy alloy phase:

[0033] The Fe-Co-Ni-Cr high-entropy alloy phase forms an FCC structure through the multi-principal element solid solution effect, combining high strength and high plasticity. The introduction of carbon further enhances the alloy phase's hardness through solid solution strengthening. Simultaneously, the nanocrystalline structure dissipates energy through grain boundary sliding and dislocation motion, imparting excellent fracture toughness to the film (no radial cracks in Vickers indentation under a 10N load). Furthermore, the FCC high-entropy alloy phase absorbs stress through plastic deformation during the exfoliation process, reducing crack initiation and ensuring film integrity.

[0034] (2) Amorphous chromium carbide ceramic phase:

[0035] Cr and C form an amorphous chromium carbide phase through strong covalent bonds (Cr-C). This high chemical bonding significantly enhances the film's cohesion, maintaining its structural integrity after peeling. The disordered structure of the amorphous phase effectively inhibits crack propagation while serving as a rigid support for the high-entropy alloy phase, enhancing the film's overall rigidity. Furthermore, the high chemical inertness of the amorphous chromium carbide phase imparts excellent corrosion resistance to the film (the corrosion current density is as low as 1.3×10 in a 3.5 wt.% NaCl solution). -8 A / cm 2 , which is one order of magnitude lower than that of 304 stainless steel).

[0036] (3) Graphite phase lubrication and stress buffering:

[0037] Excess carbon forms a graphite phase under metal catalysis. The lubricating properties of graphite reduce the film's friction coefficient to 0.15. The graphite phase acts as a soft interlayer, releasing interfacial stress through slip deformation, allowing the film to withstand 180° bending without cracking, significantly improving its flexibility.

[0038] 2. Self-supporting advantages of nanocomposite structures

[0039] (1) Nanocrystalline / amorphous composite design:

[0040] By adjusting the HiPIMS deposition parameters, a uniform distribution of nanocrystalline high-entropy alloy phases and amorphous chromium carbide phases is achieved. The nanocrystalline phase provides high strength, the amorphous phase inhibits crack propagation, and the graphite phase buffers interfacial stress, forming a multi-level "rigid-tough-lubricated" structure. This gives the film both high hardness and fracture toughness (no cracking at a bending radius of <5mm).

[0041] (2) Low residual stress:

[0042] HPPMS technology's high ionization rate (>50%) and ion energy control (via bias voltage) optimize film density and reduce void defects. By optimizing process parameters, residual stress within the film is evenly distributed (<800MPa), avoiding the risk of peeling and cracking caused by localized stress concentration, ensuring that the film does not warp or crack after peeling.

[0043] 3. Precise adaptation of the stripping process

[0044] (1) Hydrochloric acid selectively corrodes the aluminum substrate:

[0045] The aluminum substrate has a low interfacial bonding strength with the film, allowing hydrochloric acid etching to quickly dissolve the substrate without damaging the film. The high acid corrosion resistance of the amorphous chromium carbide phase (Cr-C bond energy reaches 435kJ / mol) ensures the integrity of the film during wet stripping.

[0046] (2) Mechanical peeling of silicon substrate:

[0047] The interface between the silicon substrate and the film is designed with weak bonding (such as the introduction of a graphite buffer layer), and the interface fracture energy is low during mechanical peeling (similar to the graphene peeling process), which can achieve efficient preparation of large-area self-supporting films, and the thickness can be precisely controlled at 1-5μm (too thin may lead to mechanical deficiencies, and too thick may affect flexibility).

[0048] In summary, this invention, through multiphase nanocomposite structure design and HiPIMS process optimization, breaks through the technical bottleneck of the difficulty in synergistically improving the strength, toughness, and corrosion resistance of traditional self-supporting films. The film has high hardness, can withstand bending radii less than 5 mm without cracking, has a friction coefficient of 0.15, and has wear resistance more than 10 times that of traditional metal films. In a 3.5wt.% NaCl solution, the corrosion current density is as low as 1.3×10 -8 A / cm 2 , and its pitting corrosion resistance is significantly better than that of 304 stainless steel. In addition, the process is well controllable. Through the coordinated regulation of metal splicing targets and reaction gases, multiphase in-situ synthesis and residual stress control can be accurately achieved. The self-supporting high-entropy films prepared by this method can be directly used in flexible electronics, biomedicine, extreme environment protection and other fields without the need for additional support layers, simplifying the device integration process. This technology provides a new paradigm for the industrial preparation of high-performance self-supporting films, with significant practical value and market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 These are the TEM test results and indentation toughness test results of the FeCoNiCrC high entropy film in Example 1 of the present invention.

[0050] Figure 2 This is the self-supporting performance result of the FeCoNiCrC high entropy film in Example 1 of the present invention. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0052] Example 1

[0053] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0054] (1) Pre-plating treatment

[0055] The substrate was placed in acetone and ultrasonically cleaned for 15 minutes, then ultrasonically cleaned in anhydrous ethanol for 15 minutes, and finally taken out and blown dry with nitrogen.

[0056] (2) Plasma glow discharge sputtering cleaning

[0057] The substrate treated in step (1) was placed in the cavity of a high-power pulsed magnetron sputtering device. The cavity was not heated and the intrinsic vacuum was pre-evacuated to 2.0×10 -3 Then, Ar gas with a purity greater than or equal to 99.999% is introduced into the cavity, the pressure in the cavity is 3.0 Pa, and a negative bias of -1500 V is applied to the substrate. At this time, Ar plasma is generated near the substrate. + The substrate was bombarded continuously under negative bias for 20 min.

[0058] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0059] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40sccm, introduce acetylene gas at a flow rate of 3sccm. Maintain the vacuum degree in the chamber at 0.5Pa; the average power of the FeCoNiCr spliced ​​target is 4W / cm 2 , a -50V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 40 minutes.

[0060] (4) After the film deposition is completed, the film is cooled to below 100°C in a vacuum environment, then vented to atmospheric pressure, the cavity is opened and the furnace is taken out to obtain a FeCoNiCrC high entropy nanocomposite film on the surface of the substrate.

[0061] (5) The film coated on the aluminum alloy substrate was placed in a hydrochloric acid etching solution. After the aluminum alloy substrate was completely corroded and dissolved, the film was transferred to a NaHCO3 solution and immersed for 5 minutes to neutralize the residual HCl. Then, it was ultrasonically cleaned with deionized water and ethanol for 10 minutes to remove the surface AlCl3 crystals and organic residues. After drying, a self-supporting FeCoNiCrC high-entropy nanocomposite film was obtained. The film coated on the silicon wafer surface was scratched along the edge of the substrate using a diamond probe to induce interfacial cracks. Then, a PDMS stamp was used to adhere to the film surface and slowly peeled off at a 45° angle to obtain a self-supporting FeCoNiCrC high-entropy nanocomposite film.

[0062] The FeCoNiCrC high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0063] (1) The carbon content in the film was measured by EDS and was 25 at.%. The microstructure of the film was characterized by TEM. Figure 1 The TEM results of (a) show that the film is composed of FCC nanocrystals, amorphous phase and graphite nanocrystal phase.

[0064] (2) Self-supporting properties of the film. Figure 2 (a) and 2(b) demonstrate the self-supporting properties of the film. Figure 2 (c) shows that after the film is bent 180° and observed under a scanning electron microscope, there are no crack defects at the bend, indicating excellent self-supporting properties.

[0065] (3) The nanohardness of the film on the surface of the stainless steel substrate was measured using the continuous stiffness method using an MTS-Nano G200 nanoindenter. The measurement results are shown in Table 1. The hardness of the FeCoNiCrC high-entropy nanocomposite film is 13.1 GPa.

[0066] (4) The toughness of the film on the silicon wafer substrate was tested using the Vickers indenter method with a maximum loading force of 10N. Figure 1 As shown in (b), no radial cracks were observed, indicating that the film has excellent toughness.

[0067] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear testing machine. The coated stainless steel sample and the friction pair slid back and forth with a sliding frequency of 3 Hz and a load of 2 N. The ambient temperature was (15 ± 3) °C, the relative humidity was (55 ± 5)%, and a Φ = 6 mm alumina ball was used as the friction pair. The average friction coefficient and wear rate are shown in Table 1. The average friction coefficient is 0.49 and the wear rate is 8.2 × 10 -6 mm 3 / N·m.

[0068] (6) The internal stress of the film on the silicon wafer substrate was measured using the curvature method, and the results are shown in Table 1. Due to the nanocomposite multi-level stress dissipation microstructure of the film, the internal stress of the film is as low as 100 MPa, ensuring that the film will not curl or crack due to excessive stress after peeling.

[0069] Example 2

[0070] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0071] (1) Pre-plating treatment

[0072] Same as step 1 in Example 1.

[0073] (2) Plasma glow discharge sputtering cleaning

[0074] Same as step 2 of Example 1.

[0075] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0076] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40sccm, and the acetylene flow rate at 1sccm. Maintain the vacuum degree in the chamber at 0.5Pa; the average power of the FeCoNiCr spliced ​​target is 4W / cm 2 , a -50V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 40 minutes.

[0077] (4) Same as step 4 in Example 1.

[0078] (5) Same as step 5 of Example 1.

[0079] The FeCoNiCrC high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0080] (1) The carbon content in the film was measured by EDS and was 4.2 at.%. TEM results showed that the film was composed of FeCoNiCr nanocrystals with FCC structure, and the grains were finer than those in Example 1.

[0081] (2) The film is self-supporting, but due to insufficient strength, it cracks after being bent 180°.

[0082] (3) Nanohardness test results are shown in Table 1. The hardness of the FeCoNiCr high entropy film is 8.1 GPa. Due to the solid solution strengthening effect of a small amount of carbon atoms, the hardness of the film is slightly improved compared with Example 2.

[0083] (4) The toughness of the film on the silicon wafer substrate was tested using the Vickers indenter method. The results showed that no radial cracks were observed in the film indentation, indicating that the film has excellent toughness.

[0084] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear tester. The test results are shown in Table 1. Due to the low hardness of the film, it failed due to wear during the friction test.

[0085] (6) The internal stress of the thin film on the silicon wafer substrate was measured using the curvature method. The results are shown in Table 1.

[0086] Example 3

[0087] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0088] (1) Pre-plating treatment

[0089] Same as step 1 in Example 1.

[0090] (2) Plasma glow discharge sputtering cleaning

[0091] Same as step 2 of Example 1.

[0092] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0093] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40sccm, and the acetylene flow rate at 2sccm. Maintain the vacuum degree in the chamber at 0.5Pa; the average power of the FeCoNiCr spliced ​​target is 4W / cm 2 , a -50V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 40 minutes.

[0094] (4) Same as step 4 in Example 1.

[0095] (5) Same as step 5 of Example 1.

[0096] The FeCoNiCrC high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0097] (1) EDS measurements of the carbon content in the film revealed a carbon content of 8.5 at.%. TEM results showed that the film consisted of two phases: FCC nanocrystals and an amorphous phase. The incorporation of a large number of carbon atoms caused severe distortion of the high-entropy alloy lattice, leading to the precipitation of an amorphous phase.

[0098] (2) The film is self-supporting and remains intact after being bent 180°.

[0099] (3) Nanohardness test results are shown in Table 1. The hardness of the FeCoNiCr high entropy film is 10.7 GPa.

[0100] (4) The toughness of the film on the silicon wafer substrate was tested using the Vickers indenter method. The results showed that no radial cracks were observed in the film indentation, indicating that the film has excellent toughness.

[0101] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear tester. The test results are shown in Table 1. Due to the increased hardness of the film, the wear resistance was improved, and no wear-through failure occurred.

[0102] (6) The internal stress of the thin film on the silicon wafer substrate was measured using the curvature method. The results are shown in Table 1.

[0103] Example 4

[0104] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0105] (1) Pre-plating treatment

[0106] Same as step 1 in Example 1.

[0107] (2) Plasma glow discharge sputtering cleaning

[0108] Same as step 2 of Example 1.

[0109] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0110] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40sccm, and the acetylene flow rate at 4sccm. Maintain the vacuum degree in the chamber at 0.5Pa; the average power of the FeCoNiCr spliced ​​target is 4W / cm 2 , a -50V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 40 minutes.

[0111] (4) Same as step 4 in Example 1.

[0112] (5) Same as step 5 of Example 1.

[0113] The FeCoNiCrC high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0114] (1) The carbon content in the film was measured by EDS and was 47.3 at.%. TEM results showed that the film was composed of FCC nanocrystals, amorphous phase and a large amount of graphite nanocrystal phase.

[0115] (2) The film is self-supporting. After being bent 180°, there are a few cracks at the bend of the film. This is because too much graphite phase is precipitated, which increases the brittleness of the film and reduces the deformation energy.

[0116] (3) Nanohardness test results are shown in Table 1. The hardness of the FeCoNiCr high entropy film is 16.7 GPa.

[0117] (4) The toughness of the film on the silicon wafer substrate was tested by the Vickers indentation method. The results showed that radial cracks appeared at the indentation of the film. This was because too much graphite phase precipitated in the film, and the brittleness of graphite caused the toughness of the film to decrease.

[0118] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear tester. The test results are shown in Table 1. Due to the precipitation of a large amount of graphite phase in the film, it has a lubricating effect, so the friction coefficient is significantly reduced.

[0119] (6) The internal stress of the thin film on the silicon wafer substrate was measured using the curvature method. The results are shown in Table 1.

[0120] Comparative Example 1

[0121] Carbon-free FeCoNiCr high-entropy self-supporting films were prepared on 304 stainless steel, aluminum alloy, and Si substrates with prefabricated graphite weak interface layers. The preparation methods are as follows:

[0122] (1) Pre-plating treatment

[0123] Same as step 1 in Example 1.

[0124] (2) Plasma glow discharge sputtering cleaning

[0125] Same as step 2 of Example 1.

[0126] (3) Deposition of FeCoNiCr high entropy nanocomposite film

[0127] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40sccm, and do not introduce acetylene gas. Maintain the vacuum degree in the chamber at 0.5Pa; the average power of the FeCoNiCr spliced ​​target is 4W / cm 2 , a -50V bias is applied to the substrate, and a FeCoNiCr high entropy film is deposited on the substrate surface for 40 minutes.

[0128] (4) Same as step 4 in Example 1.

[0129] (5) Same as step 5 of Example 1.

[0130] The FeCoNiCr high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0131] (1) Film microstructure: TEM morphology results show that the film is composed of FeCoNiCr nanocrystals with FCC structure.

[0132] (2) Self-supporting properties of the film. The film is self-supporting, but due to insufficient film strength, it cracks after being bent 180°.

[0133] (3) Nanohardness test results are shown in Table 1. The hardness of the FeCoNiCr high entropy film is 7.1 GPa.

[0134] (4) The toughness of the film on the silicon wafer substrate was tested using the Vickers indenter method. The results showed that no radial cracks were observed in the film indentation, indicating that the film has excellent toughness.

[0135] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear tester. The test results are shown in Table 1. Since the film is composed of a pure alloy phase and has a low hardness, it fails due to wear during the friction test.

[0136] (6) The internal stress of the thin film on the silicon wafer substrate was measured using the curvature method. The results are shown in Table 1.

[0137] Comparative Example 2

[0138] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0139] (1) Pre-plating treatment

[0140] Same as step 1 in Example 1.

[0141] (2) Plasma glow discharge sputtering cleaning

[0142] Same as step 2 of Example 1.

[0143] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0144] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40sccm. Maintain the vacuum degree in the chamber at 0.5Pa; the average power of the FeCoNiCr spliced ​​target is 4W / cm 2 Instead of using acetylene, a graphite target was used as the carbon source. The parameters of the graphite target high-power pulse power supply were 800V-200μs-250Hz. A -50V bias was applied to the substrate to deposit a FeCoNiCrC high-entropy nanocomposite film on the substrate surface for 40 minutes.

[0145] (4) Same as step 4 in Example 1.

[0146] (5) Same as step 5 of Example 1.

[0147] The FeCoNiCrC high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0148] (1) The carbon content in the film was measured by EDS to be 15.2 at.%. TEM results showed that the film was composed of FCC nanocrystals and amorphous carbon phases. Compared with the acetylene gas carbon source, the graphite target solid carbon source has a lower ionization rate, resulting in insufficient particle energy. During the film formation process, it is difficult for carbon atoms to fully diffuse and rearrange to form an ordered graphite phase, and thus precipitate in the form of amorphous carbon. In addition, the lower ionization rate results in low reactivity of carbon atoms, making it difficult for them to react with Cr in the film to form a chromium carbide ceramic phase.

[0149] (2) The film has no self-supporting properties. This is because the film lacks the chromium carbide ceramic phase and cannot form a rigid support. At the same time, it lacks the soft graphite phase and cannot buffer stress by slipping, so it does not have self-supporting properties.

[0150] (3) Nanohardness test results are shown in Table 1. The hardness of the FeCoNiCr high entropy film is 8.5 GPa.

[0151] (4) The toughness of the film on the silicon wafer substrate was tested by the Vickers indentation method. The results showed that radial cracks appeared at the indentation of the film. This was because the film lacked a hard chromium carbide ceramic phase that could pin the cracks, resulting in a decrease in the toughness of the film.

[0152] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear tester. The test results are shown in Table 1. Due to the low hardness and poor toughness of the film, wear-through failure occurred.

[0153] (6) The internal stress of the thin film on the silicon wafer substrate was measured using the curvature method. The results are shown in Table 1.

[0154] Comparative Example 3

[0155] FeCoNiCuC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0156] (1) Pre-plating treatment

[0157] Same as step 1 in Example 1.

[0158] (2) Plasma glow discharge sputtering cleaning

[0159] Same as step 2 of Example 1.

[0160] (3) Deposition of FeCoNiCuC high entropy nanocomposite film

[0161] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged, the flow rate is 40sccm. Maintain the vacuum degree in the chamber at 0.5Pa; replace the Cr strips in Example 1 with Cu strips, splice them into FeCoNiCu targets, and the average power of the target is 4W / cm 2 , using graphite target as carbon source, the parameters of graphite target high power pulse power supply are 800V-200μs-250Hz, applying -50V bias to the substrate, and depositing FeCoNiCuC high entropy nanocomposite film on the substrate surface for 40min.

[0162] (4) Same as step 4 in Example 1.

[0163] (5) Same as step 5 of Example 1.

[0164] The FeCoNiCrC high entropy nanocomposite film prepared above was subjected to the following structural and performance tests:

[0165] (1) The carbon content in the film was measured by EDS and was 13.5 at.%. TEM results showed that the film was composed of FCC nanocrystals and amorphous carbon phases. Compared with the acetylene gas carbon source, the graphite target solid carbon source has a lower ionization rate, resulting in insufficient particle energy. During the film formation process, it is difficult for carbon atoms to fully diffuse and rearrange to form an ordered graphite phase, and thus precipitate in the form of amorphous carbon. In addition, Fe, Co, Ni, and Cu are all weak carbide-forming elements and cannot react with C to form the corresponding carbide hard ceramic phase at lower deposition temperatures.

[0166] (2) The film has no self-supporting properties. This is because the film lacks the carbide ceramic phase and cannot form a rigid support. At the same time, it lacks the soft graphite phase and cannot buffer stress by slipping, so it does not have self-supporting properties.

[0167] (3) Nanohardness test results are shown in Table 1. The hardness of the FeCoNiCr high entropy film is 7.8 GPa.

[0168] (4) The toughness of the film on the silicon wafer substrate was tested by the Vickers indentation method. The results showed that radial cracks appeared at the indentation of the film. This was because the film lacked a hard carbide ceramic phase that could pin the cracks, resulting in a decrease in the toughness of the film.

[0169] (5) The friction and wear properties of the film on the surface of the stainless steel substrate were tested using a UMT-3 multifunctional friction and wear tester. The test results are shown in Table 1. Due to the low hardness and poor toughness of the film, wear-through failure occurred.

[0170] (6) The internal stress of the thin film on the silicon wafer substrate was measured using the curvature method. The results are shown in Table 1.

[0171] Table 1 shows the phase structure, nanohardness, internal stress, indentation toughness, friction coefficient, wear rate, corrosion current density and self-supporting performance of the films in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3.

[0172] Comparative Example 4

[0173] FeCoNiCuC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0174] (1) Pre-plating treatment

[0175] Same as step 1 in Example 1.

[0176] (2) Plasma glow discharge sputtering cleaning

[0177] Same as step 2 of Example 1.

[0178] (3) Deposition of FeCoNiCuC high entropy nanocomposite film

[0179] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged at 40 sccm, introduce acetylene gas at a flow rate of 3 sccm. Maintain the vacuum degree in the chamber at 0.5 Pa; replace the Cr strips in Example 1 with Cu strips and splice them into a FeCoNiCu target. The average power of the target is 4 W / cm 2 , a -50V bias voltage was applied to the substrate, and a FeCoNiCuC high entropy nanocomposite film was deposited on the substrate surface for 40 minutes.

[0180] (4) After the film deposition is completed, the film is cooled to below 100°C in a vacuum environment, then vented to atmospheric pressure, and the chamber is opened and removed from the furnace to obtain a FeCoNiCrC high-entropy nanocomposite film on the substrate surface. It can be observed that the film has cracks on the surface due to excessive internal stress, making subsequent film peeling and structural and performance characterization impossible.

[0181] Table 1

[0182]

[0183]

[0184] Example 5

[0185] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0186] (1) Pre-plating treatment

[0187] The substrate was placed in acetone and ultrasonically cleaned for 15 minutes, then ultrasonically cleaned in anhydrous ethanol for 15 minutes, and finally taken out and blown dry with nitrogen.

[0188] (2) Plasma glow discharge sputtering cleaning

[0189] The substrate treated in step (1) was placed in the cavity of a high-power pulsed magnetron sputtering device. The cavity was not heated and the intrinsic vacuum was pre-evacuated to 1×10 -3 Then, Ar gas with a purity greater than or equal to 99.999% is introduced into the cavity, the pressure in the cavity is 3.0 Pa, and a negative bias of -1500 V is applied to the substrate. At this time, Ar plasma is generated near the substrate. + The substrate was bombarded continuously under negative bias for 10 min.

[0190] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0191] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then Ar gas was introduced at a flow rate of 10 sccm, and acetylene gas was introduced to maintain the vacuum degree in the chamber at 0.2 Pa; the average power of the FeCoNiCr spliced ​​target was 4 W / cm 2 , a -100V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 20 min.

[0192] (4) After the film deposition is completed, the film is cooled to below 100°C in a vacuum environment, then vented to atmospheric pressure, the cavity is opened and the furnace is taken out to obtain a FeCoNiCrC high entropy nanocomposite film on the surface of the substrate.

[0193] (5) The film coated on the aluminum alloy substrate is placed in a hydrochloric acid etching solution. After the aluminum alloy substrate is completely corroded and dissolved, the film is transferred to a NaHCO3 solution and immersed for a certain period of time to neutralize the residual HCl. Then, it is ultrasonically cleaned with deionized water and ethanol in sequence to remove the AlCl3 crystals and organic residues on the surface. After drying, a self-supporting FeCoNiCrC high-entropy nanocomposite film is obtained. The film coated on the silicon wafer surface is scratched along the edge of the substrate using a diamond probe to induce interfacial cracks. Then, a PDMS stamp is used to adhere to the film surface and slowly peeled off at a certain angle to obtain a self-supporting FeCoNiCrC high-entropy nanocomposite film.

[0194] Example 6

[0195] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0196] (1) Pre-plating treatment

[0197] The substrate was placed in acetone and ultrasonically cleaned for 15 minutes, then ultrasonically cleaned in anhydrous ethanol for 15 minutes, and finally taken out and blown dry with nitrogen.

[0198] (2) Plasma glow discharge sputtering cleaning

[0199] The substrate treated in step (1) was placed in the cavity of a high-power pulsed magnetron sputtering device. The cavity was not heated and the intrinsic vacuum was pre-evacuated to 5.0×10 -3 Then, Ar gas with a purity greater than or equal to 99.999% is introduced into the cavity, the pressure in the cavity is 4.0Pa, and a negative bias of -1500V is applied to the substrate. At this time, Ar plasma is generated near the substrate. + The substrate was bombarded continuously under negative bias for 30 min.

[0200] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0201] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then introduced Ar gas with a flow rate of 90 sccm, and introduced acetylene gas to maintain the vacuum degree in the chamber at 2.0 Pa; the average power of the FeCoNiCr spliced ​​target was 8 W / cm 2 , a -50V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 80min.

[0202] (4) After the film deposition is completed, the film is cooled to below 80°C in a vacuum environment, then vented to atmospheric pressure, the cavity is opened and the furnace is taken out to obtain a FeCoNiCrC high entropy nanocomposite film on the substrate surface.

[0203] (5) The film coated on the aluminum alloy substrate is placed in a hydrochloric acid etching solution. After the aluminum alloy substrate is completely corroded and dissolved, the film is transferred to a NaHCO3 solution and immersed for a certain period of time to neutralize the residual HCl. Then, it is ultrasonically cleaned with deionized water and ethanol in sequence to remove the AlCl3 crystals and organic residues on the surface. After drying, a self-supporting FeCoNiCrC high-entropy nanocomposite film is obtained. The film coated on the silicon wafer surface is scratched along the edge of the substrate using a diamond probe to induce interfacial cracks. Then, a PDMS stamp is used to adhere to the film surface and slowly peeled off at a certain angle to obtain a self-supporting FeCoNiCrC high-entropy nanocomposite film.

[0204] Example 7

[0205] FeCoNiCrC high entropy nanocomposite self-supporting films were prepared on 304 stainless steel, aluminum alloy and Si substrate with prefabricated graphite weak interface layer, respectively. The preparation methods are as follows:

[0206] (1) Pre-plating treatment

[0207] The substrate was placed in acetone and ultrasonically cleaned for 15 minutes, then ultrasonically cleaned in anhydrous ethanol for 15 minutes, and finally taken out and blown dry with nitrogen.

[0208] (2) Plasma glow discharge sputtering cleaning

[0209] The substrate treated in step (1) was placed in the cavity of a high-power pulsed magnetron sputtering device. The cavity was not heated and the intrinsic vacuum was pre-evacuated to 3.0×10 -3 Then, Ar gas with a purity greater than or equal to 99.999% is introduced into the cavity, the pressure in the cavity is 4.0Pa, and a negative bias of -1500V is applied to the substrate. At this time, Ar plasma is generated near the substrate. + The substrate was bombarded under negative bias for 15 min.

[0210] (3) Deposition of FeCoNiCrC high entropy nanocomposite film

[0211] First, the chamber is evacuated to 1×10 -3 Pa~5×10 -3 Pa, then Ar gas was introduced at a flow rate of 60 sccm, and acetylene gas was introduced to maintain the vacuum degree in the chamber at 1.0 Pa; the average power of the FeCoNiCr spliced ​​target was 6 W / cm 2 , a -80V bias voltage was applied to the substrate, and a FeCoNiCrC high entropy nanocomposite film was deposited on the substrate surface for 60 min.

[0212] (4) After the film deposition is completed, the film is cooled to below 100°C in a vacuum environment, then vented to atmospheric pressure, the cavity is opened and the furnace is taken out to obtain a FeCoNiCrC high entropy nanocomposite film on the surface of the substrate.

[0213] (5) The film coated on the aluminum alloy substrate is placed in a hydrochloric acid etching solution. After the aluminum alloy substrate is completely corroded and dissolved, the film is transferred to a NaHCO3 solution and immersed for a certain period of time to neutralize the residual HCl. Then, it is ultrasonically cleaned with deionized water and ethanol in sequence to remove the AlCl3 crystals and organic residues on the surface. After drying, a self-supporting FeCoNiCrC high-entropy nanocomposite film is obtained. The film coated on the silicon wafer surface is scratched along the edge of the substrate using a diamond probe to induce interfacial cracks. Then, a PDMS stamp is used to adhere to the film surface and slowly peeled off at a certain angle to obtain a self-supporting FeCoNiCrC high-entropy nanocomposite film.

[0214] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-entropy nanocomposite film with self-supporting properties, characterized in that: The following steps are involved: High-power pulsed magnetron sputtering was used, with metal strips of four elements, Fe, Co, Ni, and Cr, spliced ​​together as sputtering targets. High-purity Ar and carbon-containing gas were used as working gases. A negative bias was applied to the surface-cleaned substrate, and a target voltage was applied to the metal spliced ​​target to deposit high-entropy nanocomposite films. The substrate bias voltage is -100V to 0V; the sputtering power of the metal splicing target is 4 to 8W / cm 2 The working gas Ar flow rate is 10 to 90 sccm, and the pressure in the chamber is maintained at 0.2 to 2.0 Pa during the sputtering coating process; the deposition time is 20 to 80 minutes; The carbon-containing gas source is acetylene, and the acetylene flow rate is 1 to 4 sccm; After the high entropy nanocomposite film is deposited, it is cooled in a vacuum environment, and then the air is released and the cavity is opened and the furnace is taken out, so that a high entropy nanocomposite film with self-supporting properties is obtained on the surface of the substrate.

2. The method for preparing a self-supporting high-entropy nanocomposite film according to claim 1, wherein: The metal splicing target is a splicing target formed by periodically arranging metal strip targets of four elements: Fe, Co, Ni, and Cr.

3. The method for preparing a self-supporting high-entropy nanocomposite film according to claim 1, wherein: The substrate is an aluminum alloy or a silicon substrate.

4. The method for preparing a self-supporting high-entropy nanocomposite film according to claim 3, wherein: The method also includes obtaining a self-supporting film by selectively corroding an aluminum substrate with hydrochloric acid or mechanically peeling off a silicon substrate through a high entropy nanocomposite film with self-supporting properties.

5. The method for preparing a self-supporting high-entropy nanocomposite film according to claim 1, wherein: The surface cleaning treatment of the substrate includes one or more of ultrasonic cleaning and plasma glow discharge sputtering cleaning; Plasma glow discharge cleaning refers to placing the substrate into the cavity of the magnetron sputtering equipment, and the cavity background vacuum is pumped to 1×10 - 3 Pa~5×10 -3 Pa, and then high-purity Ar is introduced into the cavity, the pressure in the cavity is adjusted to 3-4 Pa, a negative bias of -1500 V is applied to the substrate, and Ar plasma is generated near the substrate. The Ar in the plasma + Bias reverse sputtering cleaning is performed by bombarding the substrate under negative bias voltage.

6. A high entropy nanocomposite film with self-supporting properties, characterized in that: The high-entropy nanocomposite film with self-supporting properties is prepared by the preparation method of any one of claims 1-5. The components of the high-entropy nanocomposite film with self-supporting properties are as follows in atomic percentage: 5 to 35 at.% of Fe, Co, Ni, and Cr, respectively; 10 to 40 at.% of carbon atoms; and the sum of the atomic percentages of the above components is 100%.

7. The self-supporting high-entropy nanocomposite film according to claim 6, characterized in that: The thickness of the high-entropy nanocomposite film with self-supporting properties is 1-5 μm.

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