Silicon-nitrogen co-doped modified light high-entropy alloy film, preparation method and application

Abstract

The invention relates to the technical field of surface protection, in particular to a silicon-nitrogen co-doped modified light high-entropy alloy film and a preparation method and application thereof.The film sequentially comprises a Cr bonding layer, a CrN transition layer and an AlCrTiNbZrSiN working layer from a metal matrix to the surface, and the AlCrTiNbZrSiN working layer comprises, by atomic percent, 7%-12% of Al, 5%-10% of N, 5%-10% of Si and the balance Fe. 7 to 12 percent of Cr; 7 to 12 percent of Ti; 7%-12% of Zr; 7%-12% of Nb; 5%-10% of Si; 25-55% of N, and the thin film is of a typical cubic crystalline structure. According to the preparation method, a multi-component strong nitride element light alloy target material is subjected to magnetron sputtering, silicon and nitrogen modification elements are introduced at the same time, a novel nano-composite structure refractory high-entropy alloy film is formed, and the nano-composite structure refractory high-entropy alloy film has the beneficial effects of being compact, high in bonding strength, resistant to corrosion, excellent in high-temperature protection performance and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of surface protection, and particularly relates to a silicon-nitrogen co-doped modified lightweight high-entropy alloy thin film, a preparation method and an application thereof. Background Art

[0002] Alloying based on doping is an important means for material creation, but the traditional design concept is still limited to the dilute alloying strategy of single matrix elements. The emergence of multi-component high-entropy materials has broken through the limitation of the mixing enthalpy of the single-component system, providing a broad chemical space for the design and development of new materials. High-entropy alloy materials have a high-entropy effect thermodynamically, a lattice distortion effect structurally, a sluggish diffusion effect kinetically, and a cocktail effect in terms of performance, and are expected to break through the limits of traditional alloy materials in terms of properties such as hardness, toughness, wear resistance, corrosion resistance, and high-temperature stability. Among them, refractory high-entropy alloys, as a branch of high-entropy alloys, are a special type of high-entropy alloy that combines high-melting-point refractory elements and have great potential for applications in aerospace and other fields. However, typical refractory high-entropy alloys contain heavy elements (such as W, Ta, Mo, etc.), resulting in a relatively high density of the alloy, which severely restricts their practical industrial applications. Currently, researchers have developed lightweight refractory high-entropy alloys by adding low-density elements (such as Al, Ti, Zr, etc.), but the traditional vacuum melting method will produce obvious macroscopic and microscopic segregation and coarse grains during the solidification and cooling process, thereby affecting the properties of the alloy, and the process of regulating the alloy composition by the powder metallurgy method is very complex.

[0003] Magnetron sputtering, as a widely used vacuum coating technology, has the advantages of fast film deposition rate, low substrate temperature, good adhesion, and the ability to achieve large-area coating, and has gradually been applied to the preparation and development of high-entropy alloy thin films. Combining the characteristics of high-entropy multi-components, using a multi-element alloy target can fix the element composition of the thin film and control its thickness at the micro-nano scale, and can be used as the surface protection layer of aerospace mechanical moving parts, showing great engineering application prospects. However, the hardness and wear resistance of high-entropy alloy thin films are lower than those of traditional vapor deposition hard thin films. Common strengthening methods such as solid solution strengthening, fine grain strengthening, and phase transformation strengthening have limited effects on improving the hardness of high-entropy alloy thin films. For example, in Chinese Patent Application CN202310739730.2 "A high-hardness titanium-zirconium-niobium-hafnium-nickel amorphous high-entropy alloy thin film and its preparation method and application" and Chinese Patent Application CN202211246074.4 "A high-entropy alloy composite film and its preparation method and application", the hardness of the prepared high-entropy alloy thin films is lower than 10 GPa, which cannot meet the requirements of harsh friction conditions such as high frequency and high load. In addition, the adaptability and durability of high-entropy alloy thin films in the marine environment also need to be solved urgently.

[0004] In view of the above defects, the creator of the present invention finally obtained the present invention through long-term research and practice. Summary of the Invention

[0005] The object of the present invention is to solve the problem of how to prepare a lightweight refractory high-entropy alloy film with high density, high hardness and corrosion resistance, and provides a silicon and nitrogen co-doped modified lightweight high-entropy alloy film, a preparation method and an application thereof.

[0006] To achieve the above object, the present invention discloses a silicon and nitrogen co-doped modified lightweight high-entropy alloy film. The film sequentially includes a Cr bonding layer, a CrN transition layer, and an AlCrTiNbZrSiN working layer from the metal substrate to the surface. The elemental composition of the AlCrTiNbZrSiN working layer is calculated by atomic percentage as follows: Al: 7-12%; Cr: 7-12%; Ti: 7-12%; Zr: 7-12%; Nb: 7-12%; Si: 5-10%; N: 25-55%.

[0007] The AlCrTiNbZrSiN working layer is a nanocomposite structure with amorphous wrapping nanocrystals, and the nanocrystals are face-centered cubic crystal structures.

[0008] The thickness of the Cr bonding layer is 0.1-0.2 μm, the thickness of the CrN transition layer is 0.1-0.5 μm, and the thickness of the AlCrTiNbZrSiN working layer is 1-3 μm.

[0009] The metal substrate is any one of high-strength steel, superalloy, titanium alloy, stainless steel, and cemented carbide materials.

[0010] The present invention also discloses a preparation method of the above silicon and nitrogen co-doped modified lightweight high-entropy alloy film, including the following steps:

[0011] S1: First, grind and polish the metal substrate to a mirror surface, then perform ultrasonic cleaning with ethanol and deionized water for 20-40 min in sequence, and then dry it for standby.

[0012] S2: Fix the metal substrate on the turntable of the magnetron sputtering device. After pumping the chamber vacuum to 5×10 -3 Pa, introduce 100-130 sccm of argon gas, set the substrate bias voltage to -900 to -1100 V, and perform argon ion etching for 20-40 min.

[0013] S3: After the argon ion etching is completed, introduce 110-130 sccm of argon gas, set the substrate bias voltage to -100 to -200 V, set the Cr target power to 700-900 W, and sputter-deposit the Cr bonding layer on the metal substrate for 5-15 min; then introduce 30-50 sccm of nitrogen gas, keep the substrate bias voltage and the Cr target power unchanged, and deposit and sputter the CrN transition layer on the Cr bonding layer for 20-40 min.

[0014] S4: After the deposition of the CrN transition layer is completed, argon and nitrogen are introduced. The nitrogen flow rate is 10 - 100 sccm. The substrate bias voltage is set to -50 - -300 V, and the power of the AlCrTiNbZrSi alloy target is set to 700 - 900 W. The AlCrTiNbZrSiN working layer is sputter-deposited for a deposition duration of 2 - 10 h.

[0015] In the step S3, the purity of the Cr target is 99.99%.

[0016] In the step S3, the conditions for depositing the CrN transition layer are: the deposition pressure is 0.2 - 0.6 Pa, the deposition temperature is 100 - 400 °C, and the rotation speed of the turntable is 2 - 4 rpm.

[0017] In the step S4, the atomic number ratio of the elements in the AlCrTiNbZrSi alloy target is Al:Cr:Ti:Nb:Zr:Si = 9:9:9:9:9:5. The AlCrTiNbZrSi alloy target is prepared by the powder metallurgy method.

[0018] In the step S4, the conditions for depositing the AlCrTiNbZrSiN working layer are: the deposition pressure is 0.2 - 0.6 Pa, the deposition temperature is 100 - 400 °C, and the rotation speed of the turntable is 2 - 4 rpm.

[0019] The present invention also discloses the application of the above-mentioned silicon and nitrogen co-doped modified lightweight high-entropy alloy film in the field of surface protection of aerospace components.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The silicon and nitrogen co-doped modified lightweight high-entropy alloy film proposed by the present invention incorporates the design concept of multi-phase and multi-interface. Through the introduction of non-metal atoms into the high-entropy alloy film system, an in-situ reaction ceramic phase is generated to obtain a nanocomposite film. Due to the presence of the nitride ceramic phase and the interface strengthening effect, the film has high strength, and the phase interface inhibits the generation and propagation of cracks, making the film have high toughness. Finally, the high-entropy alloy film exhibits the characteristics of strong toughness integration.

[0022] 2. The silicon and nitrogen co-doped modified lightweight high-entropy alloy film prepared in the present invention introduces strong nitride-forming elements with lower density to form a high-toughness face-centered cubic structure crystalline film, which has characteristics such as high density and strong bonding. The nano-hardness is not less than 20 GPa, which is significantly higher than that of the undoped and unmodified high-entropy alloy film. In addition, elements such as Al, Cr, Ti, Nb, and Zr that are prone to passivation in the film are easy to form a dense oxide film, and the addition of an appropriate amount of Si accelerates the formation of the oxide film, further improving the corrosion and high-temperature protection performance of the film.

[0023] 3. The preparation method of the silicon and nitrogen co-doped modified lightweight high-entropy alloy film in the present invention uses magnetron sputtering to deposit a high-cost-performance multi-element alloy target, avoiding the problem of poor uniformity caused by co-sputtering of multiple targets. The preparation process is simple, environmentally friendly, has high production efficiency and strong versatility, is suitable for large-area uniform preparation, and is easy to realize industrial application and promotion, enabling the high-entropy alloy film in the present invention to be applied to the surface protection field of aerospace components. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the silicon and nitrogen co-doped modified lightweight high-entropy alloy film of the present invention;

[0025] Figure 2 It is a cross-sectional morphology diagram of the film in Example 1 of the present invention;

[0026] Figure 3 It is an HRTEM diagram of the film in Example 2 of the present invention;

[0027] Figure 4 It is a SAED diagram of the film in Example 2 of the present invention;

[0028] Figure 5 It is the Vickers indentation morphology of the film in Example 3 of the present invention;

[0029] Figure 6 It is a surface morphology diagram of the film in Example 1 of the present invention;

[0030] Figure 7 It is a surface morphology diagram of the film in Comparative Example 1 of the present invention;

[0031] Figure 8 It is a surface morphology diagram of the film in Comparative Example 2 of the present invention;

[0032] Figure 9 It is an XRD pattern of the films in Examples 1-3 and Comparative Examples 1-3 of the present invention;

[0033] Figure 10 It is the nano-hardness and elastic modulus of the films in Examples 1-3 and Comparative Examples 1-3 of the present invention;

[0034] Figure 11 It is an XRD pattern of the films in Example 3 and Comparative Example 3 of the present invention after annealing at 800 °C.

[0035] The numbers in the figures represent:

[0036] 1 - metal matrix; 2 - Cr bonding layer; 3 - CrN transition layer; 4 - AlCrTiNbZrSiN working layer. DETAILED DESCRIPTION OF THE INVENTION

[0037] The following further elaborates on the above and other technical features and advantages of the present invention with reference to the accompanying drawings.

[0038] Figure 1 Schematic diagram for the preparation of the silicon and nitrogen co-doped modified lightweight high-entropy alloy film in Examples 1-3. The film sequentially includes a Cr bonding layer 2, a CrN transition layer 3, and an AlCrTiNbZrSiN working layer 4 from the metal substrate 1 to the surface.

[0039] Example 1

[0040] A silicon and nitrogen co-doped modified lightweight high-entropy alloy film, which sequentially includes a Cr bonding layer, a CrN transition layer, and an AlCrTiNbZrSiN working layer from the metal substrate to the surface. The specific preparation steps are as follows:

[0041] S1: First, grind and polish the high-strength steel substrate to a mirror surface, then ultrasonically clean it with ethanol and deionized water for 30 min in sequence, and then dry it for standby.

[0042] S2: Fix the high-strength steel substrate on the turntable of the magnetron sputtering device. After pumping the chamber vacuum to 2×10 -3 Pa, introduce 120 sccm of argon gas, set the substrate bias voltage to -1000 V, and perform argon ion etching for 30 min.

[0043] S3: After the argon ion etching is completed, introduce 120 sccm of argon gas, with a deposition temperature of 150 °C, a deposition pressure of 0.6 Pa, a turntable rotation speed of 3 rpm, set the substrate bias voltage to -150 V, set the Cr target power to 800 W, and sputter-deposit a Cr bonding layer on the metal substrate for 10 min; then introduce 40 sccm of nitrogen gas, keep the substrate bias voltage and the Cr target power unchanged, and deposit and sputter a CrN transition layer on the Cr bonding layer for 30 min.

[0044] S4: After the deposition of the CrN transition layer is completed, introduce argon gas and nitrogen gas, with a nitrogen gas flow rate of 25 sccm, keep the deposition temperature, deposition pressure, and turntable rotation speed unchanged, set the substrate bias voltage to -150 V, set the AlCrTiNbZrSi alloy target power to 800 W, and sputter-deposit an AlCrTiNbZrSiN working layer for 4.2 h. Finally, take out the film sample after sufficient cooling in the furnace.

[0045] The thickness of the prepared film is 1.82 μm; the film composition is Al 9.87 at%, Ti 9.02 at%, Cr 10.55 at%, Nb 8.72 at%, Zr 8.07 at%, Si 6.72 at%, N 47.05 at%; the film phase is characterized by XRD as a typical face-centered cubic (FCC) crystal structure.

[0046] Example 2

[0047] A silicon and nitrogen co-doped modified lightweight high-entropy alloy thin film, which sequentially includes a Cr bonding layer, a CrN transition layer, and an AlCrTiNbZrSiN working layer from the metal substrate to the surface. The specific preparation steps are as follows:

[0048] S1: First, grind and polish the aviation A100 high-strength steel substrate to a mirror surface, then perform ultrasonic cleaning with ethanol and deionized water for 30 min in sequence, and then dry it for standby.

[0049] S2: Fix the high-strength steel substrate on the turntable of the magnetron sputtering device. After pumping the chamber vacuum to 2×10 -3 Pa, introduce 120 sccm argon gas, set the substrate bias voltage to -1000 V, and perform argon ion etching for 30 min.

[0050] S3: After the argon ion etching is completed, introduce 120 sccm argon gas, the deposition temperature is 150 °C, the deposition pressure is 0.6 Pa, the turntable rotation speed is 3 rpm, set the substrate bias voltage to -150 V, set the Cr target power to 800 W, and sputter-deposit the Cr bonding layer on the metal substrate for 10 min; then introduce 40 sccm nitrogen gas, keep the substrate bias voltage and the Cr target power unchanged, and deposit and sputter the CrN transition layer on the Cr bonding layer for 30 min.

[0051] S4: After the deposition of the CrN transition layer is completed, introduce argon gas and nitrogen gas, the nitrogen gas flow rate is 40 sccm, keep the deposition temperature, deposition pressure and turntable rotation speed unchanged, set the substrate bias voltage to -150 V, set the AlCrTiNbZrSi alloy target power to 800 W, and sputter-deposit the AlCrTiNbZrSiN working layer for 5.2 h. Finally, take out the thin film sample after sufficient cooling in the furnace.

[0052] The composition of the prepared thin film is Al 9.36 at%, Ti 8.59 at%, Cr 9.52 at%, Nb 7.89 at%, Zr 7.38 at%, Si 6.40 at%, N 50.86 at%; the hardness of the thin film measured by nanoindentation is 28 GPa, and the elastic modulus is 342 GPa.

[0053] Example 3

[0054] A silicon and nitrogen co-doped modified lightweight high-entropy alloy thin film, which sequentially includes a Cr bonding layer, a CrN transition layer, and an AlCrTiNbZrSiN working layer from the metal substrate to the surface. The specific preparation steps are as follows:

[0055] S1: First, grind and polish the high-strength steel substrate to a mirror surface, then perform ultrasonic cleaning with ethanol and deionized water for 30 min in sequence, and then dry it for standby.

[0056] S2: Fix the high-strength steel substrate on the turntable of the magnetron sputtering device. After evacuating the chamber vacuum to 2×10 -3 Pa, introduce 120 sccm of argon gas, set the substrate bias voltage to -1000 V, and perform argon ion etching for 30 minutes.

[0057] S3: After the argon ion etching is completed, introduce 120 sccm of argon gas, with a deposition temperature of 150 °C, a deposition pressure of 0.6 Pa, a turntable rotation speed of 3 rpm, set the substrate bias voltage to -150 V, set the Cr target power to 800 W, and sputter-deposit a Cr bonding layer on the metal substrate for 10 minutes; then introduce 40 sccm of nitrogen gas, keep the substrate bias voltage and the Cr target power unchanged, and deposit and sputter a CrN transition layer on the Cr bonding layer for 30 minutes.

[0058] S4: After the deposition of the CrN transition layer is completed, introduce argon gas and nitrogen gas, with a nitrogen gas flow rate of 55 sccm, keep the deposition temperature, deposition pressure, and turntable rotation speed unchanged, set the substrate bias voltage to -150 V, set the AlCrTiNbZrSi alloy target power to 800 W, and sputter-deposit an AlCrTiNbZrSiN working layer for 6.2 h. Finally, take out the thin film sample after sufficient cooling in the furnace.

[0059] Perform electrochemical corrosion tests on the thin film samples prepared in Examples 2 - 3 and the high-strength steel substrate under a simulated marine environment (3.5 wt% NaCl). The electrochemical corrosion test results are shown in Table 1 below:

[0060] Table 1 Electrochemical Corrosion Test Results

[0061] Sample Example 2 Example 3 A100 high-strength steel substrate Self-corrosion potential (mV) -0.143 -0.236 -0.424 <![CDATA[Self - corrosion current density (μA·cm 2 )]]> 0.085 0.077 7.466

[0062] The test results of electrochemical corrosion show that the thin film samples prepared in Examples 2 - 3 have a relatively high self-corrosion potential and a relatively low self-corrosion current density, greatly enhancing the corrosion resistance of the A100 high-strength steel substrate for aviation, and proving that the high-entropy alloy thin film in the present invention has good corrosion resistance in a marine environment.

[0063] Figure 2 is the cross-sectional morphology diagram of Example 1, and the thin film shows an obvious columnar growth structure.

[0064] Figure 3 and Figure 4 are the HRTEM diagram and the corresponding SAED diagram of Example 2. The thin film shows a composite structure of amorphous wrapping nanocrystals.

[0065] Figure 5 is the Vickers indentation morphology of Example 3. The extended crack is relatively short, indicating good strength and toughness.

[0066] Comparative Example 1

[0067] In this comparative example, an equimolar ratio of AlCrTiNbZr alloy target was used to prepare an AlCrTiNbZr high-entropy alloy film without doped silicon and nitrogen under the condition of not introducing nitrogen. A Cr bonding layer, a CrN transition layer, and an AlCrTiNbZr working layer were sequentially deposited on the metal substrate. The AlCrTiNbZr working layer was prepared using an equimolar ratio of AlCrTiNbZr alloy target. The specific preparation steps are as follows:

[0068] S1: First, grind and polish the high-strength steel substrate to a mirror surface, then perform ultrasonic cleaning with ethanol and deionized water for 30 min in sequence, and then dry it for standby.

[0069] S2: Fix the high-strength steel substrate on the turntable of the magnetron sputtering device. After pumping the chamber vacuum to 2×10 -3 Pa, introduce 120 sccm of argon gas, set the substrate bias voltage to -1000 V, and perform argon ion etching for 30 min.

[0070] S3: After the argon ion etching is completed, introduce 120 sccm of argon gas, the deposition temperature is 150 °C, the deposition pressure is 0.6 Pa, the turntable rotation speed is 3 rpm, set the substrate bias voltage to -150 V, set the Cr target power to 800 W, and sputter-deposit a Cr bonding layer on the metal substrate for 10 min; then introduce 40 sccm of nitrogen gas, keep the substrate bias voltage and the Cr target power unchanged, and deposit and sputter a CrN transition layer on the Cr bonding layer for 30 min.

[0071] S4: After the deposition of the CrN transition layer is completed, introduce 120 sccm of argon gas, keep the deposition temperature, deposition pressure, and turntable rotation speed unchanged, set the substrate bias voltage to -150 V, set the AlCrTiNbZr alloy target power to 800 W, and sputter-deposit the AlCrTiNbZr working layer for 2.6 h. Finally, take out the film sample after full furnace cooling.

[0072] The thickness of the prepared film is 2.07 μm; the film is a typical amorphous structure; the film hardness measured by nanoindentation is 13 GPa, and the elastic modulus is 236 GPa.

[0073] Comparative Example 2

[0074] In this comparative example, an equimolar ratio of AlCrTiNbZr alloy target was used to prepare an AlCrTiNbZrN high-entropy alloy film doped only with nitrogen under the condition of introducing nitrogen. A Cr bonding layer, a CrN transition layer, and an AlCrTiNbZrN working layer were sequentially deposited on the metal substrate. The specific preparation steps are as follows:

[0075] S1: First, grind and polish the high-strength steel substrate to a mirror surface, then ultrasonically clean it with ethanol and deionized water for 30 min in sequence, and then dry it for standby.

[0076] S2: Fix the high-strength steel substrate on the turntable of the magnetron sputtering device. After pumping the chamber vacuum to 2×10 -3 Pa, introduce 120 sccm argon gas, set the substrate bias voltage to -1000 V, and perform argon ion etching for 30 min.

[0077] S3: After the argon ion etching is completed, introduce 120 sccm argon gas, with a deposition temperature of 150 °C, a deposition pressure of 0.6 Pa, a turntable rotation speed of 3 rpm, set the substrate bias voltage to -150 V, set the Cr target power to 800 W, and sputter-deposit a Cr bonding layer on the metal substrate for 10 min; then introduce 40 sccm nitrogen gas, keep the substrate bias voltage and Cr target power unchanged, and deposit a sputtered CrN transition layer on the Cr bonding layer for 30 min.

[0078] S4: After the deposition of the CrN transition layer is completed, introduce 110 sccm argon gas and 10 sccm nitrogen gas, keep the deposition temperature, deposition pressure and turntable rotation speed unchanged, set the substrate bias voltage to -150 V, set the AlCrTiNbZr alloy target power to 800 W, and sputter-deposit an AlCrTiNbZr working layer for 3.2 h. Finally, take out the thin film sample after full furnace cooling.

[0079] The thickness of the prepared thin film is 2.07 μm; the thin film is a typical amorphous structure; the hardness of the thin film measured by nanoindentation is 13 GPa, and the elastic modulus is 236 GPa.

[0080] Comparative Example 3

[0081] In this comparative example, the same AlCrTiNbZrSi alloy target as in the example is used to prepare an AlCrTiNbZrSi high-entropy alloy thin film doped only with silicon without introducing nitrogen gas. Deposit a Cr bonding layer, a CrN transition layer and an AlCrTiNbZrSi working layer on the metal substrate in sequence, and its specific preparation steps are as follows:

[0082] S1: First, grind and polish the high-strength steel substrate to a mirror surface, then ultrasonically clean it with ethanol and deionized water for 30 min in sequence, and then dry it for standby.

[0083] S2: Fix the high-strength steel substrate on the turntable of the magnetron sputtering device. After pumping the chamber vacuum to 2×10 -3 Pa, introduce 120 sccm argon gas, set the substrate bias voltage to -1000 V, and perform argon ion etching for 30 min.

[0084] S3: After the argon ion etching is completed, introduce 120 sccm of argon gas, with a deposition temperature of 150 °C, a deposition pressure of 0.6 Pa, a turntable rotation speed of 3 rpm, set the substrate bias voltage to -150 V, set the Cr target power to 800 W, and sputter-deposit a Cr bonding layer on the metal substrate for 10 min; then introduce 40 sccm of nitrogen gas, keep the substrate bias voltage and the Cr target power unchanged, and deposit a sputtered CrN transition layer on the Cr bonding layer for 30 min.

[0085] S4: After the deposition of the CrN transition layer is completed, introduce 120 sccm of argon gas, keep the deposition temperature, deposition pressure, and turntable rotation speed unchanged, set the substrate bias voltage to -150 V, set the AlCrTiNbZrSi alloy target power to 800 W, and sputter-deposit the AlCrTiNbZrSi working layer for 3 h. Finally, take out the thin film sample after sufficient cooling in the furnace.

[0086] The thickness of the prepared thin film is 2.18 μm; the thin film composition is Al 16.21 at%, Ti 18.26 at%, Cr 19.07 at%, Nb 17.78 at%, Zr 16.54 at%, Si 12.14 at%; the thin film is a typical amorphous structure; the nanoindentation measures the hardness of the thin film to be 14 GPa and the elastic modulus to be 154 GPa.

[0087] Compare the thin film samples in the examples and comparative examples and conduct the following tests:

[0088] Figures 6 to 8 is the surface morphology diagram of Example 1 and Comparative Examples 1-2. The surface of the comparative example sample is loose in particles, while the high-entropy alloy thin film surface in the example is smooth and dense, which is beneficial to improving the corrosion resistance.

[0089] Figure 9 is the XRD pattern of Examples 1-3 and Comparative Examples 1-3. The comparative example sample has typical amorphous structure characteristics, while obvious diffraction peaks of face-centered cubic structure crystals appear in the example thin film. The prepared high-entropy alloy thin film is a crystalline thin film and forms a nanocomposite structure of amorphous wrapping nanocrystals.

[0090] Figure 10 is the nano-hardness and elastic modulus of Examples 1-3 and Comparative Examples 1-3. The nano-hardness of the thin film samples in the examples is not less than 20 GPa, which is significantly higher than that of the comparative example samples, indicating that the high-entropy alloy thin film prepared by the present invention has excellent mechanical properties.

[0091] Figure 11 is the XRD pattern of Example 3 and Comparative Example 3 before and after vacuum annealing at 800 °C. No new phase is formed in Example 3 at 800 °C. Compared with Comparative Example 3 after annealing, an HCP phase precipitates in the thin film, indicating that the high-temperature stability of the example is better.

[0092] The above are only the preferred embodiments of the present invention, which are illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, or even equivalents can be made within the spirit and scope defined by the claims of the present invention, and all of them will fall within the protection scope of the present invention.

Claims

1. A silicon-nitrogen co-doped modified lightweight high entropy alloy film, characterized in that: The film comprises a Cr bonding layer, a CrN transition layer and an AlCrTiNbZrSiN working layer in sequence from the metal substrate to the surface. The element composition of the AlCrTiNbZrSiN working layer is calculated by atomic percentage as follows: Al: 7-12%; Cr: 7-12%; Ti: 7-12%; Zr: 7-12%; Nb: 7-12%; Si: 5-10%; and N: 25-55%.

2. A silicon-nitrogen co-doped modified lightweight high entropy alloy film as claimed in claim 1, characterized in that: The AlCrTiNbZrSiN working layer is a nano-composite structure in which amorphous materials wrap nano-crystals, and the nano-crystals are face-centered cubic crystal structures.

3. The silicon-nitrogen co-doped modified lightweight high entropy alloy film according to claim 1, characterized in that: The thickness of the Cr bonding layer is 0.1-0.2 μm, the thickness of the CrN transition layer is 0.1-0.5 μm, and the thickness of the AlCrTiNbZrSiN working layer is 1-3 μm.

4. The silicon-nitrogen co-doped modified lightweight high entropy alloy film according to claim 1, characterized in that: The metal matrix is ​​any one of high-strength steel, high-temperature alloy, titanium alloy, stainless steel and hard alloy material.

5. A method for preparing a silicon-nitrogen co-doped modified lightweight high entropy alloy film as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1: First, grind and polish the metal substrate to a mirror surface, then ultrasonically clean it with ethanol and deionized water for 20 to 40 minutes, and then dry it for use. S2: Fix the metal substrate on the rotating frame of the magnetron sputtering device and evacuate the chamber to a vacuum of 5×10 -3 After Pa, 100 to 130 sccm of argon gas is introduced, the substrate bias voltage is set to -900 to -1100 V, and argon ion etching is performed for 20 to 40 minutes. S3: After the argon ion etching is completed, 110-130sccm argon gas is introduced, the substrate bias is set to -100-200V, the Cr target power is set to 700-900W, and a Cr bonding layer is sputtered and deposited on the metal substrate for 5-15min; then 30-50sccm nitrogen gas is introduced, the substrate bias and Cr target power are kept unchanged, and a sputtered CrN transition layer is deposited on the Cr bonding layer for 20-40min. S4: After the deposition of the CrN transition layer is completed, argon and nitrogen are introduced, the nitrogen flow rate is 10 to 100 sccm, the substrate bias is set to -50 to -300 V, the AlCrTiNbZrSi alloy target power is set to 700 to 900 W, and the AlCrTiNbZrSiN working layer is sputtered and deposited for 2 to 10 hours.

6. The method for preparing a silicon-nitrogen co-doped modified light high entropy alloy film according to claim 5, characterized in that: In the step S3, the purity of the Cr target is 99.99%.

7. The method for preparing a silicon-nitrogen co-doped modified lightweight high entropy alloy film according to claim 5, characterized in that: In the step S3, the conditions for depositing the CrN transition layer are: a deposition pressure of 0.2-0.6 Pa, a deposition temperature of 100-400° C., and a rotating rack speed of 2-4 rpm.

8. The method for preparing a silicon-nitrogen co-doped modified light high entropy alloy film according to claim 5, characterized in that: In the step S4, the atomic ratio of the elements in the AlCrTiNbZrSi alloy target is Al:Cr:Ti:Nb:Zr:Si=9:9:9:9:9:5, and the AlCrTiNbZrSi alloy target is prepared by powder metallurgy.

9. The method for preparing a silicon-nitrogen co-doped modified light high entropy alloy film according to claim 5, characterized in that: In the step S4, the conditions for depositing the AlCrTiNbZrSiN working layer are: the deposition pressure is 0.2-0.6 Pa, the deposition temperature is 100-400° C., and the rotating speed is 2-4 rpm.

10. Use of the silicon-nitrogen co-doped modified lightweight high entropy alloy film as claimed in any one of claims 1 to 4 in the field of surface protection of aerospace parts.

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