High-entropy nano-composite film with self-supporting performance and preparation method of high-entropy nano-composite film

Abstract

The invention provides a high-entropy nano composite film with self-supporting performance and a preparation method. The preparation method comprises the following steps that a high-power pulse magnetron sputtering method is adopted, metal strips of four elements of Fe, Co, Ni and Cr are spliced together to serve as a sputtering target material, high-purity Ar and a carbon-containing gas source serve as working gas, negative bias voltage is applied to a substrate subjected to surface cleaning treatment, target voltage is applied to the metal splicing target, and high-entropy nano composite film deposition is conducted; and after deposition of the high-entropy nano-composite film is completed, cooling the high-entropy nano-composite film to 80 DEG C or below in a vacuum environment, deflating, opening the cavity and discharging the high-entropy nano-composite film out of the furnace, so that the high-entropy nano-composite film with the self-supporting performance is obtained on the surface of the substrate. The thin film comprises the following components in atomic percent: 5-35 at.% of Fe, 5-35 at.% of Co, 5-35 at.% of Ni, 5-35 at.% of Cr and 10-40 at.% of carbon atoms, and the sum of the atomic percent of the components is 100%. Through component design and process innovation, collaborative optimization of high hardness, high toughness, corrosion resistance and self-supporting performance is achieved.

Description

Technical Field

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

[0002] With the rapid development of fields such as flexible electronics, biomedicine, and extreme environment protection, self-supporting thin films have attracted much attention due to their independent characteristics without the need for substrate support. However, existing technologies are mostly limited to pure metals or alloy systems with low non-metal content. Such self-supporting thin films are limited by insufficient mechanical properties and corrosion resistance and are difficult to meet the requirements of complex scenarios. For example, AlCrNiTiV metal thin films deposited by cathodic vacuum arc deposition or FeCoNiCu and Bi-Sn thin films prepared by magnetron sputtering can achieve self-supporting characteristics, but they have insufficient toughness, limited corrosion resistance, and single functions. Pure metal thin films are prone to crack propagation caused by dislocation accumulation during bending or stretching, resulting in fracture; in acidic or high-temperature corrosion environments, metal thin films are prone to oxidation or pitting, severely limiting their application scenarios.

[0003] In addition, the introduction of non-metallic elements (such as carbon and nitrogen) can improve hardness, but when the carbon or nitrogen content is relatively high in traditional alloy thin films, the failure rate of peeling increases due to increased brittleness, making it difficult to balance strength and flexibility. For example, high-entropy alloy thin films show great potential in fields such as flexible electronics, biomedicine, catalytic energy storage, and extreme protection due to their high hardness, high toughness, corrosion resistance, and multifunctionality. However, traditional high-entropy alloy thin films usually rely on substrate support, and after introducing non-metallic elements (such as carbon and boron), they often have increased brittleness due to internal stress concentration or insufficient interfacial bonding force and are difficult to peel into independent thin films. 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 art, the object of the present invention is to provide a preparation method of a high-entropy nanocomposite thin film with self-supporting performance; another object of the present invention is to provide a high-entropy nanocomposite thin film with self-supporting performance.

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

[0006] As one of the objects, a preparation method of a high-entropy nanocomposite thin film with self-supporting performance includes the following steps:

[0007] Adopt the high-power pulsed magnetron sputtering method, use metal strips of four elements, namely Fe, Co, Ni, and Cr, spliced together as the sputtering target, use high-purity Ar and a carbon-containing gas source as the working gas, apply a negative bias voltage to the substrate after surface cleaning treatment, apply a target voltage to the metal spliced target, and deposit the high-entropy nanocomposite thin film.

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

[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 mosaic target is a mosaic target formed by arranging metal strip targets of four elements, Fe, Co, Ni, and Cr, in a periodic manner in sequence.

[0011] In the above technical solution, the high-power pulsed magnetron sputtering technology (HiPIMS) is adopted. Metal strips of four elements, Fe, Co, Ni, and Cr, are spliced together as the sputtering target. The composition of the metal in the film is precisely regulated by adjusting the number and arrangement of each metal strip in the mosaic target. Using high-purity Ar and a carbon-containing gas source as the working gas, a negative bias voltage is applied to the substrate after surface cleaning treatment, and a target voltage is applied to the metal mosaic target. During the deposition process, C ions obtained by dissociating the carbon-containing gas source react with part of Cr to obtain an amorphous chromium carbide ceramic phase. The remaining Cr is mutually dissolved 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, and thus a multiphase nanocomposite structure film composed of a face-centered cubic structure high-entropy alloy phase, an amorphous chromium carbide ceramic phase, and a graphite phase is obtained.

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

[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, by controlling the sputtering power of the metal mosaic target, the acetylene flow rate, and the bias voltage, the precipitation ratio and morphology of the high-entropy alloy phase, the amorphous chromium carbide ceramic phase, and the graphite phase are controlled, and thus a high-entropy film with excellent comprehensive mechanical properties is obtained.

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

[0017] Furthermore, it also includes obtaining a self-supporting film by selectively etching the aluminum substrate with hydrochloric acid or mechanically peeling the silicon substrate for the high-entropy nanocomposite film with self-supporting performance.

[0018] As a preference, the chamber is evacuated to 1×10-3 Pa to 5×10 -3 Pa.

[0019] Preferably, the purity of the four metals of the splicing target is ≥99.8%,

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

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

[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 means putting the substrate into the cavity of a magnetron sputtering device, pumping the background vacuum of the cavity to 1×10 -3 Pa to 5×10 -3 Pa, then introducing high-purity Ar into the cavity, adjusting the gas pressure in the cavity to 3 - 4 Pa, applying a negative bias voltage of -1500 V to the substrate, generating Ar plasma near the substrate, and the Ar in the plasma + Bombards the substrate under the negative bias voltage of the substrate for bias reverse sputtering cleaning.

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

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

[0026] As another purpose, a high-entropy nanocomposite film with self-supporting performance, the composition of the high-entropy nanocomposite film with self-supporting performance is in atomic percentage: Fe, Co, Ni, and Cr four metals are respectively 5 - 35 at.%, carbon atoms are 10 - 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 performance is 1 - 5 μm.

[0028] In the above technical solution, the high-entropy nanocomposite film with self-supporting performance is used to obtain a self-supporting film by selectively corroding the aluminum substrate with hydrochloric acid or mechanically peeling the silicon substrate. The film thickness is controlled within the range of 1 - 5 μm. If it is too thin, the mechanical properties are likely to be insufficient, and if it is too thick, the flexibility will be affected.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] Through high-power pulsed magnetron sputtering technology (HiPIMS) and multiphase nanocomposite structure design, the present invention successfully prepares an FeCoNiCrC high-entropy alloy film with high mechanical properties, corrosion resistance, and self-supporting characteristics. Its beneficial effects are reflected in the following aspects:

[0031] 1. Multiphase synergy enhances 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, with both high strength and high plasticity. The introduction of carbon element further improves the hardness of the alloy phase through solid solution strengthening. At the same time, the nanocrystalline structure dissipates energy synergistically through grain boundary slip and dislocation movement, endowing the film with excellent fracture toughness (no radial cracks in Vickers indentation under a 10N load). In addition, the high-entropy alloy phase with an FCC structure absorbs stress through plastic deformation during the peeling process, reducing crack initiation and ensuring the integrity of the film.

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

[0035] Cr and C form an amorphous chromium carbide phase through strong covalent bonds (Cr-C). Its high chemical bonding energy significantly improves the cohesion of the film, enabling the film to maintain its structural integrity after peeling. The disordered structure of the amorphous phase effectively inhibits crack propagation and, at the same time, acts as a hard support for the high-entropy alloy phase, enhancing the overall rigidity of the film. In addition, the high chemical inertness of the amorphous chromium carbide phase endows the film with excellent corrosion resistance (the corrosion current density is as low as 1.3×10 -8 A / cm 2 in a 3.5wt.% NaCl solution, which is one order of magnitude lower than that of 304 stainless steel).

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

[0037] The excess C element forms a graphite phase under metal catalysis. The lubricating characteristics of graphite reduce the friction coefficient of the film to 0.15. The graphite phase can act as a soft interlayer, releasing interface stress through slip deformation, enabling the film to withstand a 180° bending deformation without cracking, and significantly enhancing flexibility.

[0038] 2. Self-supporting advantages of the nanocomposite structure

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

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

[0041] (2) Low residual stress:

[0042] The high ionization rate (>50%) and ion energy regulation (through bias voltage) of the HPPMS technology optimize the film density and reduce pore defects. Through process parameter optimization, the residual stress in the film is uniformly distributed (<800 MPa), avoiding the risk of peeling and cracking caused by local stress concentration, and ensuring that the film has no warping or cracking after peeling.

[0043] 3. Precise adaptation of the peeling process

[0044] (1) Selective corrosion of the aluminum substrate with hydrochloric acid:

[0045] The interfacial bonding force between the aluminum substrate and the film is relatively low. The substrate can be quickly dissolved by hydrochloric acid corrosion without damaging the film. The high acid corrosion resistance of the amorphous chromium carbide phase (the Cr-C bond energy reaches 435 kJ / mol) ensures the integrity of the film during wet peeling.

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

[0047] The interface between the silicon substrate and the film is designed with weak bonding (such as introducing a graphite buffer layer). During mechanical peeling, the interfacial fracture energy is low (analogous to the graphene peeling process), enabling the efficient preparation of large-area self-supporting films with a thickness that can be precisely controlled within 1 - 5 μm (too thin is prone to insufficient mechanical properties, and too thick affects flexibility).

[0048] In summary, through the design of a multiphase nanocomposite structure and the optimization of the HiPIMS process, the present invention breaks through the technical bottleneck that it is difficult to synergistically improve the strength, toughness, and corrosion resistance of traditional self-supporting films. The film has high hardness, does not crack with a bending radius < 5 mm, a friction coefficient of 0.15, and the wear resistance is more than 10 times higher than that of traditional metal films. In a 3.5 wt.% NaCl solution, the corrosion current density is as low as 1.3×10 -8 A / cm 2 , and the pitting corrosion resistance is significantly better than that of 304 stainless steel. In addition, the process has good controllability. Through the coordinated regulation of metal mosaic targets and reaction gases, multi-phase in-situ synthesis and residual stress control can be precisely achieved. The self-supporting high-entropy films prepared by this method can be directly used in flexible electronics, biomedical, extreme environment protection and other fields without an additional support layer, 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. Description of the Drawings

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

[0050] Figure 2 They are the self-supporting performance results of the FeCoNiCrC high-entropy thin film in Example 1 of the present invention. Detailed implementation manners

[0051] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0052] Example 1

[0053] FeCoNiCrC high-entropy nano-composite self-supporting thin films were respectively prepared on 304 stainless steel, aluminum alloy, and Si substrate prefabricated with a graphite weak interface layer. The preparation method is as follows:

[0054] (1) Pretreatment before plating

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

[0056] (2) Plasma glow discharge sputtering cleaning

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

[0058] (3) Depositing FeCoNiCrC high-entropy nano-composite thin film

[0059] First, the cavity was evacuated to 1×10 -3 Pa to 5×10 -3 Pa, then Ar gas was introduced, and the Ar gas flow rate was kept constant at 40 sccm. Acetylene gas was introduced with a flow rate of 3 sccm. The vacuum degree in the cavity was maintained at 0.5 Pa; the average power of the FeCoNiCr splicing target was 4 W / cm 2 , a -50 V bias voltage was applied to the substrate, and a FeCoNiCrC high-entropy nano-composite thin film was deposited on the substrate surface for 40 min.

[0060] (4) After the film deposition is completed, it is cooled to below 100 °C in a vacuum environment, then the gas is released to atmospheric pressure, the chamber is opened, and the furnace is taken out, and a FeCoNiCrC high-entropy nanocomposite film is obtained on the substrate surface.

[0061] (5) The film plated 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 NaHCO 3 solution and soaked for 5 minutes to neutralize the residual HCl. Then it is ultrasonically cleaned with deionized water and ethanol for 10 minutes in turn to remove the surface AlCl 3 crystals and organic residues, and a self-supporting FeCoNiCrC high-entropy nanocomposite film is obtained after drying. The film plated on the silicon wafer surface is scribed along the substrate edge using a diamond probe to initiate an interface crack, and then a PDMS stamp is 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 following structural and property tests are carried out on the prepared FeCoNiCrC high-entropy nanocomposite film:

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

[0064] (2) Film self-supporting property. Figure 2 (a) and 2(b) show the self-supporting performance of the film. Figure 2 (c) shows that after the film is bent by 180° and observed under a scanning electron microscope, there are no crack defects at the bent part, indicating excellent self-supporting performance.

[0065] (3) The nano-hardness of the film on the stainless steel substrate surface is measured by the continuous stiffness method using an MTS-Nano G200 nano-indentation instrument. The measurement results are shown in Table 1, and 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 is tested by the Vickers indenter pressing method, and the maximum loading force is 10 N. The results are as Figure 1 (b) shows that no radial cracks are observed, indicating that the film has excellent toughness.

[0067] (5) The friction and wear properties of the thin film on 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 reciprocated in a sliding manner. The sliding frequencies were 3 Hz, the load was 2 N, the ambient temperature was (15 ± 3) °C, the relative humidity was (55 ± 5)%, and an alumina ball with Φ = 6 mm was used as the friction pair. The average friction coefficient and wear rate are shown in Table 1. The average friction coefficient was 0.49, and the wear rate was 8.2×10 -6 mm 3 / N·m.

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

[0069] Example 2

[0070] FeCoNiCrC high-entropy nano-composite self-supporting thin films were prepared on 304 stainless steel, aluminum alloy, and Si substrate prefabricated with a graphite weak interface layer respectively. The preparation method is as follows:

[0071] (1) Pretreatment before plating

[0072] The same as step 1 of Example 1.

[0073] (2) Plasma glow discharge sputtering cleaning

[0074] The same as step 2 of Example 1.

[0075] (3) Deposition of FeCoNiCrC high-entropy nano-composite thin film

[0076] First, the chamber was evacuated to 1×10 -3 Pa to 5×10 -3 Pa, then Ar gas was introduced and the Ar gas flow rate was kept constant at 40 sccm, and the acetylene flow rate was 1 sccm. The vacuum degree in the chamber was maintained at 0.5 Pa; the average power of the FeCoNiCr mosaic target was 4 W / cm 2 , a -50 V bias voltage was applied to the substrate, and the FeCoNiCrC high-entropy nano-composite thin film was deposited on the substrate surface for 40 min.

[0077] (4) The same as step 4 of Example 1.

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

[0079] The following structure and performance tests were carried out on the prepared FeCoNiCrC high-entropy nano-composite thin film:

[0080] (1) The carbon content in the thin film was measured by EDS to be 4.2 at.%. The TEM results showed that the thin film was composed of FeCoNiCr nanocrystals with an FCC structure, and the grain size was smaller compared to Example 1.

[0081] (2) The thin film had self-supporting properties, but due to insufficient film strength, the thin film cracked after 180° bending deformation.

[0082] (3) The results of nano-hardness testing are shown in Table 1. The hardness of this FeCoNiCr high-entropy thin film was 8.1 GPa, and due to the solid solution strengthening effect of a small amount of carbon atoms, the film hardness increased slightly compared to Example 2.

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

[0084] (5) The friction and wear properties of the thin film on the stainless steel substrate surface were tested using a UMT-3 multifunctional friction and wear testing machine. The test results are shown in Table 1. Due to the low hardness of the thin film, it failed by wear-through 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 nano-composite self-supporting thin films were prepared on 304 stainless steel, aluminum alloy, and Si substrates prefabricated with a graphite weak interface layer respectively. The preparation method is as follows:

[0088] (1) Pretreatment before plating

[0089] The same as step 1 of Example 1.

[0090] (2) Plasma glow discharge sputtering cleaning

[0091] The same as step 2 of Example 1.

[0092] (3) Deposition of FeCoNiCrC high-entropy nano-composite thin film

[0093] First, the chamber was evacuated to 1×10 -3 Pa to 5×10 -3 Pa, then Ar gas was introduced, and the Ar gas flow rate was kept constant at 40 sccm, and the acetylene flow rate was 2 sccm. The vacuum degree in the chamber was maintained at 0.5 Pa; the average power of the FeCoNiCr mosaic target was 4 W / cm 2 , a -50 V bias voltage was applied to the substrate, and a FeCoNiCrC high-entropy nano-composite thin film was deposited on the substrate surface for 40 min.

[0094] (4) The same as step 4 of Example 1.

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

[0096] The following structural and property tests were carried out on the prepared FeCoNiCrC high-entropy nanocomposite film:

[0097] (1) The carbon content in the film was measured by EDS to be 8.5 at.%. The TEM results showed that the film was composed of two phases, FCC nanocrystals and amorphous phase. Due to the incorporation of a large number of carbon atoms, serious lattice distortion of the high-entropy alloy occurred, and the amorphous phase began to precipitate.

[0098] (2) The film had self-supporting property. After being bent by 180°, the film remained intact.

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

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

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

[0102] (6) The internal stress of the film on the silicon wafer substrate was measured by 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 prefabricated with a graphite weak interface layer respectively. The preparation method was as follows:

[0105] (1) Pretreatment before plating

[0106] The same as step 1 of Example 1.

[0107] (2) Plasma glow discharge sputtering cleaning

[0108] The same as step 2 of Example 1.

[0109] (3) Depositing FeCoNiCrC high-entropy nanocomposite film

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

[0111] (4) The same as step 4 of Example 1.

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

[0113] Perform the following structure and property tests on the obtained FeCoNiCrC high-entropy nanocomposite film:

[0114] (1) Use EDS to measure the carbon content in the film to be 47.3 at.%. The TEM results show that the film is composed of FCC nanocrystals, amorphous phase and a large number of graphite nanocrystal phases.

[0115] (2) The film has self-supporting property. After 180° bending deformation, there are a small number of cracks at the bent part of the film because too much graphite phase precipitates, resulting in an increase in the brittleness of the film and a decrease in the deformation energy.

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

[0117] (4) Use the Vickers indenter pressing method to test the toughness of the film on the silicon wafer substrate. The results show that radial cracks appear at the indentation of the film because too much graphite phase precipitates in the film, and the brittleness of graphite leads to a decrease in the toughness of the film.

[0118] (5) Use a UMT-3 multi-functional friction and wear tester to test the friction and wear properties of the film on the stainless steel substrate surface. The test results are shown in Table 1. Since a large amount of graphite phase precipitates in the film, which plays a lubricating effect, the friction coefficient decreases significantly.

[0119] (6) Use the curvature method to measure the internal stress of the film on the silicon wafer substrate. The results are shown in Table 1.

[0120] Comparative Example 1

[0121] Prepare carbon-free FeCoNiCr high-entropy self-supporting films on 304 stainless steel, aluminum alloy and Si substrate prefabricated with a graphite weak interface layer respectively. The preparation method is as follows:

[0122] (1) Pretreatment before plating

[0123] The same as step 1 of Example 1.

[0124] (2) Plasma glow discharge sputtering cleaning

[0125] Same as step 2 of Example 1.

[0126] (3) Depositing FeCoNiCr high-entropy nanocomposite film

[0127] First, evacuate the chamber to 1×10 -3 Pa to 5×10 -3 Pa, then introduce Ar gas, keep the Ar gas flow rate unchanged, the flow rate is 40 sccm, and do not introduce acetylene gas. Maintain the vacuum degree in the chamber at 0.5 Pa; the average power of the FeCoNiCr mosaic target is 4 W / cm 2 , apply a -50 V bias voltage to the substrate, deposit the FeCoNiCr high-entropy film on the substrate surface, and the deposition time is 40 min.

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

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

[0130] The following structure and performance tests were carried out on the obtained FeCoNiCr high-entropy nanocomposite film:

[0131] (1) Microstructure of the film. The TEM morphology results show that the film is composed of FCC-structured FeCoNiCr nanocrystals.

[0132] (2) Self-supporting property of the film. The film has self-supporting property, but due to insufficient film strength, after 180° bending deformation, the film cracks.

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

[0134] (4) The film toughness on the silicon wafer substrate was tested by the Vickers indenter pressing method. The results show 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 stainless steel substrate surface were tested by a UMT-3 multi-functional friction and wear testing machine. 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 by wear-through during the friction test.

[0136] (6) The internal stress of the film on the silicon wafer substrate was measured by 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 substrates prefabricated with graphite weak interface layers respectively. The preparation method is as follows:

[0139] (1) Pretreatment before plating

[0140] Same as step 1 of Example 1.

[0141] (2) Plasma glow discharge sputtering cleaning

[0142] Same as step 2 of Example 1.

[0143] (3) Depositing FeCoNiCrC high-entropy nanocomposite film

[0144] First, the chamber was evacuated to 1×10 -3 Pa to 5×10 -3 Pa, and then Ar gas was introduced while keeping the Ar gas flow rate constant at 40 sccm. The vacuum degree in the chamber was maintained at 0.5 Pa; the average power of the FeCoNiCr mosaic target was 4 W / cm 2 . Instead of using acetylene, a graphite target was used as the carbon source. The parameters of the high-power pulsed power supply for the graphite target were 800 V - 200 μs - 250 Hz. A bias voltage of -50 V was applied to the substrate, and a FeCoNiCrC high-entropy nanocomposite film was deposited on the substrate surface for 40 min.

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

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

[0147] The following structure and performance tests were carried out on the obtained FeCoNiCrC high-entropy nanocomposite film:

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

[0149] (2) The film had no self-supporting property because it lacked chromium carbide ceramic phases and could not form a rigid support. At the same time, it lacked soft graphite phases and could not buffer stress through slip, so it did not have self-supporting performance.

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

[0151] (4) The Vickers indenter pressing method was used to test the toughness of the film on the silicon wafer substrate. The results showed that radial cracks appeared at the film indentation, because there was a lack of hard chromium carbide ceramic phase in the film that could pin the cracks, resulting in a decrease in the film toughness.

[0152] (5) The UMT-3 multi-functional friction and wear tester was used to test the friction and wear properties of the film on the stainless steel substrate surface. 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 curvature method was used to measure the internal stress of the film on the silicon wafer substrate. The results are shown in Table 1.

[0154] Comparative Example 3

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

[0156] (1) Pretreatment before plating

[0157] Same as step 1 of Example 1.

[0158] (2) Plasma glow discharge sputtering cleaning

[0159] Same as step 2 of Example 1.

[0160] (3) Depositing FeCoNiCuC high-entropy nano-composite film

[0161] First, the chamber was evacuated to 1×10 -3 Pa to 5×10 -3 Pa, then Ar gas was introduced and the Ar gas flow rate was kept constant at 40 sccm. The vacuum degree in the chamber was maintained at 0.5 Pa; the Cr bar in Example 1 was replaced with a Cu bar and assembled into a FeCoNiCu target. The average power of the target was 4 W / cm 2 , a graphite target was used as the carbon source, and the parameters of the high-power pulsed power supply of the graphite target were 800 V - 200 μs - 250 Hz. A -50 V bias voltage was applied to the substrate, and a FeCoNiCuC high-entropy nano-composite film was deposited on the substrate surface for 40 min.

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

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

[0164] The following structure and performance tests were carried out on the prepared FeCoNiCrC high-entropy nano-composite film:

[0165] (1) The carbon content in the thin film was measured to be 13.5 at.% by EDS. The TEM results showed that the thin film was composed of FCC nanocrystals and amorphous carbon phase. Compared with the acetylene gas carbon source, the ionization rate of the graphite target solid carbon source was lower, resulting in insufficient particle energy. During the film formation process, it was difficult for carbon atoms to diffuse and rearrange sufficiently to form an ordered graphite phase, so they precipitated in the form of amorphous carbon. In addition, the four elements 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 a relatively low deposition temperature.

[0166] (2) The thin film had no self-supporting property because it lacked the carbide ceramic phase to form a rigid support and lacked the soft graphite phase to buffer stress through slip, so it did not have self-supporting performance.

[0167] (3) The results of nano-hardness testing are shown in Table 1. The hardness of the FeCoNiCr high-entropy thin film was 7.8 GPa.

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

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

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

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

[0172] Comparative Example 4

[0173] FeCoNiCuC high-entropy nano-composite self-supporting thin films were prepared on 304 stainless steel, aluminum alloy, and Si substrates prefabricated with a graphite weak interface layer respectively. The preparation method is as follows:

[0174] (1) Pretreatment before plating

[0175] The same as step 1 of Example 1.

[0176] (2) Plasma glow discharge sputtering cleaning

[0177] The same as step 2 of Example 1.

[0178] (3) Deposition of FeCoNiCuC high-entropy nano-composite thin film

[0179] First, evacuate the cavity to 1×10 -3 Pa to 5×10 -3 Pa, then introduce Ar gas and keep the Ar gas flow rate constant at 40 sccm. Introduce acetylene gas with a flow rate of 3 sccm. Maintain the vacuum degree in the cavity at 0.5 Pa; replace the Cr strip in Example 1 with a Cu strip and splice it into a FeCoNiCu target. The average power of the target is 4 W / cm 2 , apply a -50 V bias voltage to the substrate, and deposit a FeCoNiCuC high-entropy nanocomposite film on the surface of the substrate for 40 minutes.

[0180] (4) After the film deposition is completed, cool it to below 100 °C in a vacuum environment, then vent to atmospheric pressure, open the cavity and take out the furnace, and obtain a FeCoNiCrC high-entropy nanocomposite film on the surface of the substrate. It can be observed that the film has cracks on the surface due to excessive internal stress, and subsequent film peeling and structure and property characterization cannot be carried out.

[0181] Table 1

[0182]

[0183]

[0184] Example 5

[0185] Prepare FeCoNiCrC high-entropy nanocomposite free-standing films on 304 stainless steel, aluminum alloy, and Si substrate prefabricated with a graphite weak interface layer respectively. The preparation method is as follows:

[0186] (1) Pretreatment before plating

[0187] Place the substrate in acetone and ultrasonically clean it for 15 minutes, then ultrasonically clean it in absolute ethanol for 15 minutes, and finally take it out and dry it with nitrogen.

[0188] (2) Plasma glow discharge sputtering cleaning

[0189] Load the substrate processed in step (1) into the cavity of a high-power pulsed magnetron sputtering device. Do not heat the cavity and pre-pump the intrinsic vacuum to 1×10 -3 Pa; then, introduce Ar gas with a purity greater than or equal to 99.999% into the cavity, the gas pressure in the cavity is 3.0 Pa, and apply a -1500 V negative bias voltage to the substrate. At this time, Ar plasma is generated near the substrate, and Ar + continuously bombards the substrate under the negative bias voltage for 10 minutes.

[0190] (3) Deposit FeCoNiCrC high-entropy nanocomposite film

[0191] First, evacuate the cavity to 1×10 -3 Pa to 5×10 -3 Pa, then introduce Ar gas with a flow rate of 10 sccm, introduce acetylene gas, and maintain the vacuum degree in the cavity at 0.2 Pa; the average power of the FeCoNiCr splicing target is 4 W / cm 2 , apply a -100 V bias voltage to the substrate, deposit a FeCoNiCrC high-entropy nanocomposite film on the substrate surface, and the deposition time is 20 min.

[0192] (4) After the film deposition is completed, cool it to below 100 °C in a vacuum environment, then vent to atmospheric pressure, open the cavity and take out the furnace, and obtain a FeCoNiCrC high-entropy nanocomposite film on the substrate surface.

[0193] (5) Place the film plated on the aluminum alloy substrate in a hydrochloric acid etching solution. After the aluminum alloy substrate is completely corroded and dissolved, transfer the film to NaHCO 3 solution and soak for a certain time to neutralize the residual HCl. Then ultrasonically clean with deionized water and ethanol in turn to remove surface AlCl 3 crystals and organic residues, and obtain a free-standing FeCoNiCrC high-entropy nanocomposite film after drying. Use a diamond probe to scratch along the edge of the substrate for the film plated on the silicon wafer surface to initiate an interfacial crack, and then use a PDMS stamp to adhere to the film surface and slowly peel it off at a certain angle to obtain a free-standing FeCoNiCrC high-entropy nanocomposite film.

[0194] Example 6

[0195] Prepare FeCoNiCrC high-entropy nanocomposite free-standing films on 304 stainless steel, aluminum alloy and Si substrates prefabricated with graphite weak interface layers respectively. The preparation method is as follows:

[0196] (1) Pretreatment before plating

[0197] Place the substrate in acetone, ultrasonically clean for 15 minutes, then ultrasonically clean in anhydrous ethanol for 15 minutes, and finally take it out and dry it with nitrogen.

[0198] (2) Plasma glow discharge sputtering cleaning

[0199] Load the substrate treated in step (1) into the cavity of a high-power pulsed magnetron sputtering device. Do not heat the cavity, and pre-pump the intrinsic vacuum to 5.0×10 -3 Pa; then, introduce Ar gas with a purity greater than or equal to 99.999% into the cavity, the gas pressure in the cavity is 4.0 Pa, and apply a -1500 V negative bias voltage to the substrate. At this time, Ar plasma is generated near the substrate, and Ar + continuously bombards the substrate under the negative bias voltage for 30 min.

[0200] (3) Depositing FeCoNiCrC high-entropy nanocomposite film

[0201] First, evacuate the chamber to 1×10 -3 Pa to 5×10 -3 Pa, then introduce Ar gas with a flow rate of 90 sccm, introduce acetylene gas, and maintain the vacuum degree in the chamber at 2.0 Pa; the average power of the FeCoNiCr mosaic target is 8 W / cm 2 , apply a -50 V bias voltage to the substrate, deposit the FeCoNiCrC high-entropy nanocomposite film on the substrate surface, and the deposition time is 80 min.

[0202] (4) After the film deposition is completed, cool it to below 80 °C in a vacuum environment, then vent to atmospheric pressure, open the chamber and take out the furnace, and obtain the FeCoNiCrC high-entropy nanocomposite film on the substrate surface.

[0203] (5) Place the film plated on the aluminum alloy substrate in the hydrochloric acid etching solution. After the aluminum alloy substrate is completely etched and dissolved, transfer the film to NaHCO 3 solution and soak it for a certain time to neutralize the residual HCl. Then ultrasonically clean it with deionized water and ethanol in turn to remove the surface AlCl 3 crystals and organic residues, and obtain the free-standing FeCoNiCrC high-entropy nanocomposite film after drying. Use a diamond probe to scratch along the substrate edge of the film plated on the silicon wafer surface to initiate an interface crack, and then use a PDMS stamp to adhere to the film surface and slowly peel it off at a certain angle to obtain the free-standing FeCoNiCrC high-entropy nanocomposite film.

[0204] Example 7

[0205] Prepare FeCoNiCrC high-entropy nanocomposite free-standing films on 304 stainless steel, aluminum alloy, and Si substrates prefabricated with graphite weak interface layers respectively. The preparation method is as follows:

[0206] (1) Pretreatment before plating

[0207] Place the substrate in acetone, ultrasonically clean it for 15 minutes, then ultrasonically clean it in absolute ethanol for 15 minutes, and finally take it out and dry it with nitrogen.

[0208] (2) Plasma glow discharge sputtering cleaning

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

[0210] (3) Deposit the FeCoNiCrC high-entropy nanocomposite film

[0211] First, evacuate the cavity to 1×10 -3 Pa to 5×10 -3 Pa, then introduce Ar gas with a flow rate of 60 sccm, introduce acetylene gas, and maintain the vacuum degree in the cavity at 1.0 Pa; the average power of the FeCoNiCr splicing target is 6 W / cm 2 , apply a bias voltage of -80 V to the substrate, and deposit the FeCoNiCrC high-entropy nanocomposite film on the substrate surface for 60 min.

[0212] (4) After the film deposition is completed, cool it to below 100 °C in a vacuum environment, then vent to atmospheric pressure, open the cavity and take out the furnace, and obtain the FeCoNiCrC high-entropy nanocomposite film on the substrate surface.

[0213] (5) Place the film plated on the aluminum alloy substrate in the hydrochloric acid etching solution. After the aluminum alloy substrate is completely corroded and dissolved, transfer the film to NaHCO 3 solution and soak it for a certain time to neutralize the residual HCl. Then ultrasonically clean it with deionized water and ethanol in turn to remove the surface AlCl 3 crystals and organic residues, and obtain the free-standing FeCoNiCrC high-entropy nanocomposite film after drying. Use a diamond probe to scratch along the edge of the substrate on the film plated on the silicon wafer surface to initiate an interface crack, and then use a PDMS stamp to adhere to the film surface and slowly peel it off at a certain angle to obtain the free-standing 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 those skilled in the art within the essence of the present invention should also fall within the protection scope 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 method is adopted, metal strips of four elements Fe, Co, Ni and Cr are spliced ​​together as sputtering targets, high-purity Ar and carbon-containing gas source are used as working gas, negative bias voltage is applied to the substrate after surface cleaning, target voltage is applied to the metal splicing target, and high-entropy nanocomposite film deposition is performed; 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 high entropy nanocomposite film with self-supporting performance according to claim 1, characterized in that: The metal spliced ​​target is a spliced ​​target formed by periodically arranging metal strip targets of four elements, Fe, Co, Ni and Cr.

3. The method for preparing a high entropy nanocomposite film with self-supporting performance according to claim 1, characterized in that: 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 min to 80 min.

4. The method for preparing a high entropy nanocomposite film with self-supporting performance according to claim 3, characterized in that: The carbon-containing gas source is acetylene or methane.

5. The method for preparing a high entropy nanocomposite film with self-supporting performance according to claim 4, characterized in that: The carbon-containing gas source is acetylene, and the acetylene flow rate is 1-4 sccm.

6. The method for preparing a high entropy nanocomposite film with self-supporting performance according to claim 1, characterized in that: The substrate is an aluminum alloy or a silicon substrate.

7. The method for preparing a high entropy nanocomposite film with self-supporting performance according to claim 6, characterized in that: 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.

8. The method for preparing a high entropy nanocomposite film with self-supporting performance according to claim 1, characterized in that: 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 chamber of the magnetron sputtering equipment and evacuating the chamber to a vacuum of 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. + Bias reverse sputtering cleaning is performed by bombarding the substrate under negative bias voltage.

9. 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 1-8. The components of the high entropy nanocomposite film with self-supporting properties are as follows in atomic percentage: Fe, Co, Ni, Cr four metals are 5-35at.%, carbon atoms are 10-40at.%, and the sum of the atomic percentages of the above components is 100%.

10. The high entropy nanocomposite film with self-supporting properties according to claim 9, characterized in that: The thickness of the high-entropy nanocomposite film with self-supporting properties is 1-5 μm.

Images