A soft metal doped tungsten disulfide-based composite film, and a preparation method and application thereof

Abstract

This invention discloses a soft metal-doped tungsten disulfide-based composite thin film, its preparation method, and its application. The composite thin film comprises a titanium transition layer, a titanium / tungsten disulfide / nickel / copper gradient layer, and a tungsten disulfide / nickel / copper layer sequentially formed on the surface of a substrate. In the titanium / tungsten disulfide / nickel / copper gradient layer, the content of titanium gradually decreases while the content of molybdenum disulfide, nickel, and copper gradually increases along the direction gradually moving away from the substrate. Simultaneously, the tungsten disulfide / nickel / copper layer is formed by alternating layers of nickel-tungsten disulfide and copper-tungsten disulfide. The composite thin film provided by this invention exhibits high hardness, elastic modulus, and bonding strength, with a high-temperature friction coefficient reaching 0.04. It also demonstrates better thermal stability and oxidation resistance, meeting the requirements for stable lubrication and long service life in aerospace vehicles.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment technology, specifically relating to a soft metal-doped tungsten disulfide-based composite thin film, its preparation method and application. Background Technology

[0002] Spacecraft often operate under extreme conditions, such as high / low temperatures or high loads, necessitating improved lifespan and reliability of rotating components like bearings to ensure safe operation. Proper lubrication of these rotating components is crucial. Transition metal sulfides (MS2, where M is molybdenum or tungsten) are widely used in aerospace due to their easily slippery layered structure formed by weak interlayer van der Waals bonds. However, ground testing or storage is sometimes required before spacecraft launch. MS2 solid lubricant coatings are highly sensitive to the environment; their layered structure contains dangling or unsaturated bonds at the edges, making them prone to reacting with oxygen and deteriorating tribological properties, significantly limiting their engineering applications. Even in a vacuum, sputtered pure MS2 films exhibit poor wear resistance due to their porous structure. The rapid development of space technology places higher demands on lubricating materials, requiring them to perform well in harsh environments such as high / low temperature cycling, high loads, and high radiation. Therefore, improving the tribological properties of MS2 coatings is essential.

[0003] For ground-level or high-temperature applications, MoS2 rapidly loses its lubricating properties and is accompanied by high wear. Therefore, other materials are needed to improve the frictional performance of coatings in harsh environments. WS2, compared to MoS2, exhibits higher thermal stability and oxidation resistance, and layered coatings prepared using it as a substrate can effectively reduce friction and wear on rotating components such as bearings in harsh environments. However, WS2-based coatings cannot self-replenish like liquid lubricants, especially under severe operating conditions. Durability issues hinder their application in applications requiring longer service life and higher torque sensitivity, such as precision bearings for rolling elements. This means that a single solid film is insufficient to meet the increasing durability requirements. Summary of the Invention

[0004] The main objective of this invention is to provide a soft metal-doped tungsten disulfide-based composite thin film, its preparation method and application, in order to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a soft metal-doped tungsten disulfide-based composite film, comprising: a titanium transition layer, a titanium / tungsten disulfide / nickel / copper gradient layer and a tungsten disulfide / nickel / copper layer sequentially formed on the surface of a substrate;

[0007] In the titanium / tungsten disulfide / nickel / copper gradient layer, the content of titanium gradually decreases, while the content of molybdenum disulfide, nickel, and copper gradually increases along the direction gradually moving away from the substrate. Meanwhile, the tungsten disulfide / nickel / copper layer is formed by alternating layers of nickel-tungsten disulfide and copper-tungsten disulfide.

[0008] This invention also provides a method for preparing the aforementioned soft metal-doped tungsten disulfide-based composite thin film, comprising:

[0009] A soft metal-doped tungsten disulfide-based composite thin film was prepared by sequentially depositing a titanium transition layer, a titanium / tungsten disulfide / nickel / copper gradient layer, and a tungsten disulfide / nickel / copper layer on the substrate surface using magnetron sputtering technology.

[0010] The present invention also provides the application of the aforementioned soft metal-doped tungsten disulfide-based composite film in the field of surface protection of aerospace devices in high-temperature or high-low temperature alternating environments.

[0011] This invention also provides an apparatus comprising a substrate on which the aforementioned soft metal-doped tungsten disulfide-based composite film is disposed.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] This invention employs magnetron sputtering technology and, through Ni and Cu doping modification design, prepares a soft metal-doped tungsten disulfide-based composite film. This composite film possesses high hardness (greater than 6.5 GPa) and elastic modulus, making it suitable for surface protection of components in high-impact environments, especially for aerospace pyrotechnic separation environments. It exhibits a strong bonding force of 20 N and a coefficient of friction of 0.04 after high-temperature treatment. It demonstrates excellent tribological properties in atmospheric environments, alternating high and low temperature environments, and various temperature environments, meeting the application requirements of components in diverse environments. Furthermore, it exhibits good temperature adaptability and high-temperature oxidation resistance, thereby improving the service life of aerospace vehicles. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a cross-sectional SEM image of the tungsten disulfide-based doped soft metal composite film prepared in Example 3 of this invention.

[0016] Figure 2This is a test diagram of the adhesion strength of the tungsten disulfide-based doped soft metal composite film prepared in Example 3 of the present invention;

[0017] Figure 3 This is a graph showing the hardness and elastic modulus of the tungsten disulfide-based doped soft metal composite film prepared in Example 3 of this invention.

[0018] Figure 4 This is a friction curve of the tungsten disulfide-based doped soft metal composite film prepared in Example 3 of the present invention after annealing at room temperature, high temperature of 600°C, and thermal vacuum test.

[0019] Figure 5 This is a wear rate diagram of the tungsten disulfide-based doped soft metal composite film prepared in Example 3 of the present invention after annealing at room temperature, high temperature of 600°C, and thermal vacuum testing. Detailed Implementation

[0020] Currently, doping is a common method to improve the load-bearing capacity and environmental adaptability of thin films for practical applications. Soft metal doping can significantly improve the mechanical and lubrication properties of thin films. Because metal elements can undergo tribochemical reactions on the friction surface at high temperatures, improving tribological performance, and because metal elements preferentially interact with O2, protecting the structure of the WS2 thin film from damage, it can also effectively improve the film's environmental adaptability. However, doped thin films obtained by co-doping tungsten disulfide with soft metals cannot achieve high hardness and ultra-low friction. Therefore, this application prepares WS2-based nanocomposite thin films doped with high-hardness soft metals Ni and Cu by reactive magnetron sputtering, achieving high hardness, high load-bearing capacity, and excellent adaptability to high-temperature and high-low-temperature alternating environments.

[0021] In view of the deficiencies of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention, which mainly uses unbalanced magnetron sputtering technology to introduce titanium and tungsten carbide into molybdenum disulfide, so that this type of composite coating can achieve ultra-low friction and wear and have good oxidation resistance in a vacuum environment.

[0022] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Specifically, as one aspect of the technical solution of the present invention, a soft metal-doped tungsten disulfide-based composite thin film includes: a titanium transition layer, a titanium / tungsten disulfide / nickel / copper gradient layer and a tungsten disulfide / nickel / copper layer sequentially formed on the surface of a substrate;

[0024] In the titanium / tungsten disulfide / nickel / copper gradient layer, the content of titanium gradually decreases, while the content of molybdenum disulfide, nickel, and copper gradually increases along the direction gradually moving away from the substrate. Meanwhile, the tungsten disulfide / nickel / copper layer is formed by alternating layers of nickel-tungsten disulfide and copper-tungsten disulfide.

[0025] In this invention, during the preparation of tungsten disulfide / nickel / copper layers, the target materials are placed opposite each other due to different rotation speeds during the preparation process. By rotating to different target material positions, a thin layer is deposited, forming a nano-multilayer alternating deposition.

[0026] In some preferred embodiments, the atomic content of nickel atoms in the soft metal-doped tungsten disulfide-based composite film is 8–12 at, and the atomic content of copper atoms is 1–4 at.

[0027] In some preferred embodiments, the thickness of the titanium transition layer is 100–200 nm.

[0028] In some preferred embodiments, the thickness of the titanium / tungsten disulfide / nickel / copper gradient layer is 100–300 nm.

[0029] In some preferred embodiments, the thickness of the tungsten disulfide / nickel / copper layer is 1.5 to 2.5 μm.

[0030] In some preferred embodiments, the thickness of the composite film is 1.5 to 3.0 μm.

[0031] In some preferred embodiments, the substrate material includes, but is not limited to, any one of 316L, 9Cr18, and monocrystalline silicon.

[0032] In some preferred embodiments, the hardness of the composite film is greater than 6.5 GPa.

[0033] In some preferred embodiments, the composite film is subjected to temperatures of -60 to 80°C and ambient pressures of ≤6.65 × 10⁻⁶. -3 The friction coefficient after thermal vacuum testing under the conditions of Pa, 2.5 cycles, and residence time ≥11.5 h was 0.06~0.07, and the wear rate was 16×10⁻⁶. -7 18×10 -7 mm 3 / Nm.

[0034] In some preferred embodiments, the composite film, after annealing at 600°C for 0.5 h, has a friction coefficient of 0.041–0.058 and a wear rate of 2.78 × 10⁻⁶. -7 N11.6×10 -7 mm 3 / Nm.

[0035] Another aspect of the present invention provides a method for preparing the aforementioned soft metal-doped tungsten disulfide-based composite thin film, comprising:

[0036] A soft metal-doped tungsten disulfide-based composite thin film was prepared by sequentially depositing a titanium transition layer, a titanium / tungsten disulfide / nickel / copper gradient layer, and a tungsten disulfide / nickel / copper layer on the substrate surface using magnetron sputtering technology.

[0037] In some preferred embodiments, the preparation method specifically includes: using magnetron sputtering technology, with a titanium target as the cathode target and an inert gas as the working gas, applying a target current to the titanium target and a negative bias voltage to the substrate, thereby depositing a titanium transition layer on the substrate surface. The target current is 3.0–5.0 A, the substrate bias voltage is -70–-100 V, the working gas flow rate is 30–35 sccm, the substrate temperature is 80–120 °C, and the reaction chamber pressure is 1.0–3.0 × 10⁻⁶. -3 torr, deposition time is 600-900s.

[0038] Furthermore, the inert gas includes, but is not limited to, argon.

[0039] In some preferred embodiments, the preparation method specifically includes: using magnetron sputtering technology, with titanium, tungsten disulfide / nickel, and tungsten disulfide / copper targets as cathode targets, and inert gas as the working gas, applying target current to the titanium, tungsten disulfide / nickel, and tungsten disulfide / copper targets, and applying a negative bias voltage to the substrate, thereby depositing a titanium / tungsten disulfide / nickel / copper gradient layer on the surface of the titanium transition layer; wherein the target current applied to the titanium target gradually decreases from 3.0–5.0 A to 0, the target current applied to the tungsten disulfide / nickel target gradually increases from 0 to 0.8–1.6 A, the target current applied to the tungsten disulfide / copper target gradually increases from 0 to 0.8–1.6 A, the substrate bias voltage is -30 to -70 V, the working gas flow rate is 30–35 sccm, the substrate temperature is 80–120 °C, and the reaction chamber pressure is 1.0–3.0 × 10⁻⁶. -3 torr, deposition time is 600-900s.

[0040] Furthermore, the inert gas includes, but is not limited to, argon.

[0041] In some preferred embodiments, the preparation method specifically includes: using magnetron sputtering technology, with tungsten disulfide / nickel targets and tungsten disulfide / copper targets as cathode targets, and an inert gas as the working gas, applying a target current to the tungsten disulfide / nickel targets and a negative bias voltage to the substrate, thereby depositing a tungsten disulfide / nickel / copper layer on the surface of the titanium / tungsten disulfide / nickel / copper gradient layer; wherein the target current applied to the tungsten disulfide / nickel target is 0.8N-1.6A, the target current applied to the tungsten disulfide / copper target is 0.8-1.6A, the target current applied to the tungsten disulfide / copper target is 0.8-1.6A, the substrate bias voltage is -30--70V, the working gas flow rate is 30-35sccm, the substrate temperature is 80-120℃, and the reaction chamber pressure is 1.0-3.0×10⁻⁶. -3 The deposition time was 9900–10300 s.

[0042] Furthermore, the inert gas includes, but is not limited to, argon.

[0043] In some preferred embodiments, the preparation method further includes: evacuating the reaction chamber to a vacuum level of 3 × 10⁻⁶. 5 Below torr, the substrate surface is first cleaned and plasma etched.

[0044] Furthermore, the conditions for the plasma etching process include: applying a bias voltage of -400 to -500V to the substrate, a substrate temperature of 100 to 150°C, and an etching time of 1200 to 1800s.

[0045] In some more specific embodiments, the method for preparing the soft metal-doped tungsten disulfide-based composite thin film includes the following steps:

[0046] (1) The titanium target sputtering current is 3–5 A, the substrate bias voltage is -70–-100 V, the working gas is Ar, the working gas flow rate is 30–35 sccm, the deposition substrate temperature is 80–120 °C, and the reaction chamber pressure is 1.0–3.0 × 10⁻⁶. -3 The deposition time is 600–900 s, and a titanium transition layer is deposited on the substrate surface.

[0047] (2) The target current on the titanium target gradually decreases from 3.0 to 5.0 A to 0, while the sputtering current applied to the tungsten disulfide / nickel target and the tungsten disulfide / copper target gradually increases from 0 to 0.8 to 1.6 A. The substrate bias voltage is -30 to -70 V, the working gas flow rate is 30 to 35 sccm, the substrate temperature is 80 to 120 °C, and the reaction chamber pressure is 1.0 to 3.0 × 10⁻⁶. -3 The deposition time is 99,000 to 112,000 s, and a titanium / tungsten disulfide / nickel / copper gradient layer is deposited on the surface of the titanium transition layer.

[0048] (3) Maintain the sputtering current of the tungsten disulfide / nickel target and the tungsten disulfide / copper target at 0.8–1.6 A, the substrate bias voltage at -30–-70 V, the working gas flow rate at 30–35 sccm, the substrate temperature at 80–120 °C, and the reaction chamber pressure at 1.0–3.0 × 10⁻⁶. -3 The deposition time is 9900–10300 s, forming a tungsten disulfide / nickel / copper layer in the titanium / tungsten disulfide / nickel / copper gradient layer.

[0049] Furthermore, the preparation method further includes: pre-evacuating the reaction chamber to a vacuum level of 3 × 10⁻⁶. -5 torr below.

[0050] Furthermore, the preparation method further includes: evacuating the reaction chamber to a predetermined vacuum level (3×10⁻⁶). -5 After (below torr), the substrate surface is first cleaned, and then plasma etching is performed. The specific etching method is to apply a bias voltage of -400 to -500V to the substrate, the etching temperature is 100 to 150℃, and the etching time is 1200 to 1800s.

[0051] Another aspect of the present invention provides the use of the aforementioned soft metal-doped tungsten disulfide-based composite film in the field of surface protection of aerospace devices in high-temperature environments or high-low temperature alternating environments.

[0052] Furthermore, the materials used in the aerospace devices include 316L, 9Cr18, or single-crystal silicon wafers, but are not limited to these.

[0053] Another aspect of the present invention provides an apparatus including a substrate on which the aforementioned soft metal-doped tungsten disulfide-based composite film is disposed.

[0054] Furthermore, the substrate material includes, but is not limited to, 316L, 9Cr18, or monocrystalline silicon wafers.

[0055] Furthermore, the device includes an aerospace vehicle.

[0056] The inventors in this case also conducted the following performance tests on the aforementioned soft metal-doped tungsten disulfide-based composite thin film:

[0057] (1) The thickness of the film was tested by scanning electron microscopy, and the results showed that the coating was 1.5 to 3.0 μm.

[0058] (2) Using a nanoindenter The hardness and elastic modulus of the thin film were measured using a diamond indenter at an indentation depth of 500 nm, with the average value taken at six points. Test results: The nanohardness of the tungsten disulfide-based doped soft metal composite thin film of this invention is greater than 6.5 GPa.

[0059] (4) The adhesion of the film was tested using the Revetest scratch testing system (CSM, Revetest). The operation was performed according to the scratch testing machine operating procedure, with three scratch tests conducted at different locations. The experimental conditions were: loading speed: 3 mm / min, scratch length: 5 mm, and loading force: 20 N. The test results showed that the adhesion of the soft metal-doped tungsten disulfide-based composite film in this invention reached 20 N (for reference). Figure 4 ).

[0060] (5) Friction and wear test: A friction testing machine (TRB3) was used to conduct reciprocating dry friction tests on films that had not undergone annealing and those that had undergone annealing at different temperatures and thermal vacuum testing under atmospheric conditions. The tests were repeated 2-3 times. 316L steel balls were used as the reference material, and a reciprocating sliding method was adopted with a frequency of 5Hz, a track length of 5mm, a running distance of 90m, and a normal load of 5N. The wear cross-section was obtained using a surface profilometer (ASTQ), and the wear volume was obtained by multiplying it by the running step length. The wear rate was obtained by dividing the wear volume by the load and the stroke. Test results: After thermal vacuum testing, the friction coefficient was 0.06-0.07, and the wear rate was 16×10-7-18×10-7mm. 3 / Nm, the friction coefficient after annealing at different temperatures is 0.041~0.058, and the wear rate is 2.78×10-7~11.6×10-7mm. 3 / Nm.

[0061] In summary, through the above technical solutions, the soft metal-doped tungsten disulfide-based composite film provided by the present invention possesses excellent hardness and elastic modulus, exhibits good tribological properties at different temperatures under atmospheric conditions, and demonstrates good temperature adaptability and high-temperature oxidation resistance, thus meeting the requirements for stable lubrication and long service life of aerospace vehicles. The technical solutions of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. These embodiments are implemented based on the technical solutions of the invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0062] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0063] Example 1

[0064] In this embodiment, the substrate material is 316L, 9Cr18, or a single-crystal silicon wafer. A tungsten disulfide-based doped soft metal composite film is prepared on the substrate surface using magnetron sputtering technology, mainly including the following steps:

[0065] The substrate surface was mechanically polished, and the substrate material was ultrasonically cleaned in acetone solution for 15 minutes. After being dried with nitrogen, it was ultrasonically cleaned in anhydrous ethanol solution for 15 minutes and then dried with nitrogen.

[0066] The cleaned substrate is placed in the magnetron sputtering chamber, and a vacuum is evacuated to a level below 5 × 10⁻⁶. -5 The substrate is then subjected to torr, followed by sputtering cleaning of the target for 30 minutes at a substrate temperature of 100-150℃. The cleaned substrate is then placed in the magnetron sputtering chamber and evacuated to a vacuum level below 5 × 10⁻⁶. -5 The substrate was sputtered and cleaned for 30 minutes at a temperature of 100-150℃. A tungsten disulfide-based doped soft metal composite film was prepared by filling the cavity with high-purity argon gas. Ti targets (99.99 at.%), WS2 / Ni targets (99.9 at.%, weight ratio 90:10), and WS2 / Cu targets (99.9 at.%, weight ratio 90:10) were used in a controlled configuration. Magnetron sputtering was employed, and the specific steps are as follows:

[0067] (1) Plasma etching: apply a bias voltage of -500V to the substrate, run for 25 minutes, and the substrate temperature is 150℃.

[0068] (2) The titanium target sputtering current is 3.0A, the substrate bias voltage is -80V, the working gas is Ar, the gas flow rate is 35sccm, the deposition substrate temperature is 100℃, and the pressure is 1.1×10⁻⁶. -3 A titanium transition layer with a thickness of approximately 100 nm was deposited on the substrate surface at a torr, a deposition time of 900 s, and a rotation speed of 2 r / min.

[0069] (3) Gradually decrease the titanium target sputtering current to 0A, while gradually increasing the sputtering currents of the WS2 / Ni target and WS2 / Cu target to 1.6A. The working gas is Ar with a flow rate of 35 sccm, the substrate bias voltage is -50V, the deposition substrate temperature is 80℃, and the pressure is 1.0×10⁻⁶. -3 A titanium / tungsten disulfide / nickel / copper gradient layer was deposited on the surface of the titanium transition layer at a torr, a deposition time of 900 s, and a rotation speed of 0.5 r / min.

[0070] (4) Maintain the sputtering current of WS2 / Ni target and WS2 / Cu target at 1.6A, the working gas as Ar with a flow rate of 35 sccm, the substrate bias voltage as -50V, the deposition substrate temperature as 80℃, and the pressure as 1.0×10⁻⁶. -3 The deposition time was 9900 s and the rotation speed was 0.5 r / min. Titanium / tungsten disulfide / nickel / copper layers were deposited on the surface of the titanium / tungsten disulfide / nickel / copper gradient layer until the total thickness of the composite film reached 2.0 μm.

[0071] The specific compositional parameters of the soft metal-doped tungsten disulfide-based composite thin film samples are shown in Table 1.

[0072] The soft metal-doped tungsten disulfide-based composite thin films prepared after the above deposition treatment were tested as follows:

[0073] (1) The thickness of the film was tested using a scanning electron microscope.

[0074] (2) Using a nanoindenter The nanohardness and elastic modulus of the film were measured. Six different regions were collected for each sample, with an indentation depth of 500 nm. The average value was calculated, and the results of the coating hardness and elastic modulus are shown in Table 2.

[0075] (4) The bonding performance of the film was tested using the Revetest scratch test system (CSM, Revetest). Three scratch tests were performed at different locations. The experimental conditions were: loading speed: 3 mm / min, scratch length: 5 mm, and loading force: 20 N. The test results are shown in Table 2.

[0076] (5) A friction testing machine (TRB3) was used to conduct reciprocating dry friction tests on films that had not undergone annealing and those that had undergone annealing at different temperatures and thermal vacuum testing under atmospheric conditions. The tests were repeated 2-3 times. 316L steel balls were used as the test material, and a reciprocating sliding method was adopted with a frequency of 5Hz, a track length of 5mm, a running distance of 90m, and a normal load of 5N. The wear cross-section was obtained using a surface profilometer (ASTQ), and the wear volume was obtained by multiplying it by the running step length. The wear rate was obtained by dividing the wear volume by the load and the stroke. The results of the friction coefficient and wear rate are shown in Tables 3 and 4, respectively.

[0077] Example 2

[0078] In this embodiment, the substrate material is 316L, 9Cr18, or a single-crystal silicon wafer. A soft metal-doped tungsten disulfide-based composite thin film is prepared on the substrate surface using magnetron sputtering technology, mainly including the following steps:

[0079] The substrate surface was mechanically polished, and the substrate material was ultrasonically cleaned in acetone solution for 15 minutes. After being dried with nitrogen, it was ultrasonically cleaned in anhydrous ethanol solution for 15 minutes and then dried with nitrogen.

[0080] The cleaned substrate is placed in the magnetron sputtering chamber, and a vacuum is evacuated to a level below 5 × 10⁻⁶. -5 The substrate is then subjected to torr, followed by sputtering cleaning of the target for 30 minutes at a substrate temperature of 100-150℃. The cleaned substrate is then placed in the magnetron sputtering chamber and evacuated to a vacuum level below 5 × 10⁻⁶. -5The substrate was sputtered and cleaned for 30 minutes at a temperature of 100-150℃. A tungsten disulfide-based doped soft metal composite film was prepared by filling the cavity with high-purity argon gas. Ti targets (99.99 at.%), WS2 / Ni targets (99.9 at.%, weight ratio 90:10), and WS2 / Cu targets (99.9 at.%, weight ratio 90:10) were used in a controlled configuration. Magnetron sputtering was employed, and the specific steps are as follows:

[0081] (1) Plasma etching: apply a bias voltage of -500V to the substrate, run for 25 minutes, and the substrate temperature is 150℃.

[0082] (2) The titanium target sputtering current is 3.0A, the substrate bias voltage is -80V, the working gas is Ar, the gas flow rate is 35sccm, the deposition substrate temperature is 100℃, and the pressure is 1.1×10⁻⁶. -3 A titanium transition layer with a thickness of approximately 100 nm was deposited on the substrate surface at a torr, a deposition time of 900 s, and a rotation speed of 2 r / min.

[0083] (3) Gradually decrease the titanium target sputtering current to 0A, while gradually increasing the WS2 / Ni target and WS2 / Cu target to 1.6A. The working gas is Ar with a flow rate of 35 sccm. The substrate bias voltage is -50V, the deposition substrate temperature is 80℃, and the pressure is 1.0×10⁻⁶. -3 A titanium / tungsten disulfide / nickel / copper gradient layer was deposited on the surface of the titanium transition layer at a torr, a deposition time of 900 s, and a rotation speed of 1.0 r / min.

[0084] (4) Maintain the sputtering current of WS2 / Ni target and WS2 / Cu target at 1.6A, the working gas as Ar with a flow rate of 35 sccm, the substrate bias voltage as -50V, the deposition substrate temperature as 80℃, and the pressure as 1.0×10⁻⁶. -3 The deposition time was 9900 s and the rotation speed was 1.0 r / min. Titanium / tungsten disulfide / nickel / copper layers were deposited on the surface of the titanium / tungsten disulfide / nickel / copper gradient layer until the total thickness of the composite film reached 2.0 μm.

[0085] The specific compositional parameters of the soft metal-doped tungsten disulfide-based composite thin film samples are shown in Table 1.

[0086] The soft metal-doped tungsten disulfide-based composite thin films prepared after the above deposition treatment were tested as follows:

[0087] (1) The thickness of the film was tested using a scanning electron microscope.

[0088] (2) Using a nanoindenter The nanohardness and elastic modulus of the film were measured. Six different regions were collected for each sample, with an indentation depth of 500 nm. The average value was calculated, and the results of the coating hardness and elastic modulus are shown in Table 2.

[0089] (4) The bonding performance of the film was tested using the Revetest scratch test system (CSM, Revetest). Three scratch tests were performed at different locations. The experimental conditions were: loading speed: 3 mm / min, scratch length: 5 mm, and loading force: 20 N. The test results are shown in Table 2.

[0090] (5) A friction testing machine (TRB3) was used to conduct reciprocating dry friction tests on films that had not undergone annealing and those that had undergone annealing at different temperatures and thermal vacuum testing under atmospheric conditions. The tests were repeated 2-3 times. 316L steel balls were used as the test material, and a reciprocating sliding method was adopted with a frequency of 5Hz, a track length of 5mm, a running distance of 90m, and a normal load of 5N. The wear cross-section was obtained using a surface profilometer (ASTQ), and the wear volume was obtained by multiplying it by the running step length. The wear rate was obtained by dividing the wear volume by the load and the stroke. The results of the friction coefficient and wear rate are shown in Tables 3 and 4, respectively.

[0091] Example 3

[0092] In this embodiment, the substrate material is 316L, 9Cr18, or a single-crystal silicon wafer. A soft metal-doped tungsten disulfide-based composite thin film is prepared on the substrate surface using magnetron sputtering technology, mainly including the following steps:

[0093] The substrate surface was mechanically polished, and the substrate material was ultrasonically cleaned in acetone solution for 15 minutes. After being dried with nitrogen, it was ultrasonically cleaned in anhydrous ethanol solution for 15 minutes and then dried with nitrogen.

[0094] The cleaned substrate is placed in the magnetron sputtering chamber, and a vacuum is evacuated to a level below 5 × 10⁻⁶. -5 The substrate is then subjected to torr, followed by sputtering cleaning of the target for 30 minutes at a substrate temperature of 100-150℃. The cleaned substrate is then placed in the magnetron sputtering chamber and evacuated to a vacuum level below 5 × 10⁻⁶. -5 The substrate was sputtered and cleaned for 30 minutes at a temperature of 100-150℃. A tungsten disulfide-based doped soft metal composite film was prepared by filling the cavity with high-purity argon gas. Ti targets (99.99 at.%), WS2 / Ni targets (99.9 at.%, weight ratio 90:10), and WS2 / Cu targets (99.9 at.%, weight ratio 90:10) were used in a controlled configuration. Magnetron sputtering was employed, and the specific steps are as follows:

[0095] (1) Plasma etching: apply a bias voltage of -500V to the substrate, run for 25 minutes, and the substrate temperature is 150℃.

[0096] (2) The titanium target sputtering current is 3.0A, the substrate bias voltage is -80V, the working gas is Ar, the gas flow rate is 35sccm, the deposition substrate temperature is 100℃, and the pressure is 1.1×10⁻⁶. -3 A titanium transition layer with a thickness of approximately 100 nm was deposited on the substrate surface at a torr, a deposition time of 900 s, and a rotation speed of 2 r / min.

[0097] (3) Gradually decrease the titanium target sputtering current to 0A, while gradually increasing the sputtering currents of the WS2 / Ni target and WS2 / Cu target to 1.6A. The working gas is Ar with a flow rate of 35 sccm, the substrate bias voltage is -50V, the deposition substrate temperature is 80℃, and the pressure is 1.0×10⁻⁶. -3 (3) The deposition time was 900s, the rotation speed was 2.0r / min, and a titanium / tungsten disulfide / nickel / copper gradient layer was deposited on the surface of the titanium transition layer; (4) The sputtering current of the WS2 / Ni target and WS2 / Cu target was kept at 1.6A, the working gas was Ar, the gas flow rate was 35sccm, the substrate bias voltage was -50V, the deposition substrate temperature was 80℃, and the pressure was 1.0×10 -3 The deposition time was 9900 s and the rotation speed was 2.0 r / min. Titanium / tungsten disulfide / nickel / copper layers were deposited on the surface of the titanium / tungsten disulfide / nickel / copper gradient layer until the total thickness of the composite film reached 2.0 μm.

[0098] The specific compositional parameters of the soft metal-doped tungsten disulfide-based composite thin film samples are shown in Table 1.

[0099] The soft metal-doped tungsten disulfide-based composite thin films prepared after the above deposition treatment were tested as follows:

[0100] (1) The thickness of the film was tested using a scanning electron microscope.

[0101] (2) Using a nanoindentation instrument The nanohardness and elastic modulus of the film were measured. Six different regions were collected for each sample, with an indentation depth of 500 nm. The average value was calculated, and the results of the coating hardness and elastic modulus are shown in Table 2.

[0102] (4) The bonding performance of the film was tested using the Revetest scratch test system (CSM, Revetest). Three scratch tests were performed at different locations. The experimental conditions were: loading speed: 3 mm / min, scratch length: 5 mm, and loading force: 20 N. The test results are shown in Table 2.

[0103] (5) A friction testing machine (TRB3) was used to conduct reciprocating dry friction tests on films that had not undergone annealing and those that had undergone annealing at different temperatures and thermal vacuum testing under atmospheric conditions. The tests were repeated 2-3 times. 316L steel balls were used as the test material, and a reciprocating sliding method was adopted with a frequency of 5Hz, a track length of 5mm, a running distance of 90m, and a normal load of 5N. The wear cross-section was obtained using a surface profilometer (ASTQ), and the wear volume was obtained by multiplying it by the running step length. The wear rate was obtained by dividing the wear volume by the load and the stroke. The results of the friction coefficient and wear rate are shown in Tables 3 and 4, respectively.

[0104] Example 4

[0105] In this embodiment, the substrate material is 316L, 9Cr18, or a single-crystal silicon wafer. A soft metal-doped tungsten disulfide-based composite thin film is prepared on the substrate surface using magnetron sputtering technology, mainly including the following steps:

[0106] The substrate surface was mechanically polished, and the substrate material was ultrasonically cleaned in acetone solution for 15 minutes. After being dried with nitrogen, it was ultrasonically cleaned in anhydrous ethanol solution for 15 minutes and then dried with nitrogen.

[0107] The cleaned substrate is placed in the magnetron sputtering chamber, and a vacuum is evacuated to a level below 5 × 10⁻⁶. -5 The substrate is then subjected to torr, followed by sputtering cleaning of the target for 30 minutes at a substrate temperature of 100-150℃. The cleaned substrate is then placed in the magnetron sputtering chamber and evacuated to a vacuum level below 5 × 10⁻⁶. -5 The substrate was sputtered and cleaned for 30 minutes at a temperature of 100-150℃. A tungsten disulfide-based doped soft metal composite film was prepared by filling the cavity with high-purity argon gas. Ti targets (99.99 at.%), WS2 / Ni targets (99.9 at.%, weight ratio 90:10), and WS2 / Cu targets (99.9 at.%, weight ratio 90:10) were used in a controlled configuration. Magnetron sputtering was employed, and the specific steps are as follows:

[0108] (1) Plasma etching: apply a bias voltage of -500V to the substrate, run for 25 minutes, and the substrate temperature is 150℃.

[0109] (2) The titanium target sputtering current is 3.0A, the substrate bias voltage is -80V, the working gas is Ar, the gas flow rate is 35sccm, the deposition substrate temperature is 100℃, and the pressure is 1.1×10⁻⁶. -3 A titanium transition layer with a thickness of approximately 100 nm was deposited on the substrate surface at a torr, a deposition time of 900 s, and a rotation speed of 2 r / min.

[0110] (3) Gradually decrease the titanium target sputtering current to 0A, while gradually increasing the sputtering currents of the WS2 / Ni target and WS2 / Cu target to 1.6A. The working gas is Ar with a flow rate of 35 sccm, the substrate bias voltage is -50V, the deposition substrate temperature is 80℃, and the pressure is 1.0×10⁻⁶. -3 A titanium / tungsten disulfide / nickel / copper gradient layer was deposited on the surface of the titanium transition layer at a torr, a deposition time of 900 s, and a rotation speed of 3.0 r / min.

[0111] (4) Maintain the sputtering current of WS2 / Ni target and WS2 / Cu target at 1.6A, the working gas as Ar with a flow rate of 35 sccm, the substrate bias voltage as -50V, the deposition substrate temperature as 80℃, and the pressure as 1.0×10⁻⁶. -3 The deposition time was 9900 s and the rotation speed was 3.0 r / min. Titanium / tungsten disulfide / nickel / copper layers were deposited on the surface of the titanium / tungsten disulfide / nickel / copper gradient layer until the total thickness of the composite film reached 2.0 μm.

[0112] The specific compositional parameters of the soft metal-doped tungsten disulfide-based composite thin film samples are shown in Table 1.

[0113] The soft metal-doped tungsten disulfide-based composite thin films prepared after the above deposition treatment were tested as follows:

[0114] (1) The thickness of the film was tested using a scanning electron microscope.

[0115] (2) Using a nanoindenter The nanohardness and elastic modulus of the film were measured. Six different regions were collected for each sample, with an indentation depth of 500 nm. The average value was calculated, and the results of the coating hardness and elastic modulus are shown in Table 2.

[0116] (4) The bonding performance of the film was tested using the Revetest scratch test system (CSM, Revetest). Three scratch tests were performed at different locations. The experimental conditions were: loading speed: 3 mm / min, scratch length: 5 mm, and loading force: 20 N. The test results are shown in Table 2.

[0117] (5) A friction testing machine (TRB3) was used to conduct reciprocating dry friction tests on films that had not undergone annealing and those that had undergone annealing at different temperatures and thermal vacuum testing under atmospheric conditions. The tests were repeated 2-3 times. 316L steel balls were used as the test material, and a reciprocating sliding method was adopted with a frequency of 5Hz, a track length of 5mm, a running distance of 90m, and a normal load of 5N. The wear cross-section was obtained using a surface profilometer (ASTQ), and the wear volume was obtained by multiplying it by the running step length. The wear rate was obtained by dividing the wear volume by the load and the stroke. The results of the friction coefficient and wear rate are shown in Tables 3 and 4, respectively.

[0118] Compare with Example 1

[0119] In this embodiment, the substrate material is 316L, 9Cr18, or a single-crystal silicon wafer. A tungsten disulfide coating is prepared on the substrate surface using magnetron sputtering technology, mainly including the following steps:

[0120] The substrate surface was mechanically polished, and the substrate material was ultrasonically cleaned in acetone solution for 15 minutes. After being dried with nitrogen, it was ultrasonically cleaned in anhydrous ethanol solution for 15 minutes and then dried with nitrogen.

[0121] The cleaned substrate is placed in the magnetron sputtering chamber, and a vacuum is evacuated to a level below 5 × 10⁻⁶. -5 The target was then sputtered and cleaned for 30 minutes at a substrate temperature of 100-150℃.

[0122] To prepare a tungsten disulfide thin film, high-purity argon gas was filled into the cavity. Ti targets (99.99 at.%) and tungsten disulfide targets (99.9 at.%) were strategically positioned, and magnetron sputtering technology was employed. The specific steps are as follows:

[0123] (1) Plasma etching: apply a bias voltage of -450V to the substrate, run for 30 minutes, and the substrate temperature is 120℃.

[0124] (2) The titanium target sputtering current is 3.0A, the substrate bias voltage is -70V, the working gas is Ar, the gas flow rate is 35sccm, the deposition substrate temperature is 80℃, and the pressure is 1.0x10⁻⁶. -3 The deposition time was 900s, and a 200nm titanium transition layer was deposited on the substrate surface.

[0125] (3) Gradually decrease the titanium target sputtering current to 0A, while gradually increasing the tungsten disulfide target sputtering current to 1.6A. The working gas is Ar, the gas flow rate is 35 sccm, the substrate bias voltage is -50V, the deposition substrate temperature is 80℃, the rotation speed is 2.0 r / min, and the pressure is 1.3 x 10⁻⁶. -3 torr, deposition time 9900s, depositing a titanium / tungsten disulfide gradient layer on the surface of the titanium transition layer;

[0126] (4) Maintain the WS2 target sputtering current at 1.6A, the working gas as Ar with a flow rate of 35 sccm, the substrate bias voltage at -50V, the deposition substrate temperature at 80℃, and the pressure at 1.0×10⁻⁶. -3 A tungsten disulfide layer was deposited on the surface of the titanium / tungsten disulfide gradient layer at a torr, a deposition time of 900 s, and a rotation speed of 0.5 r / min until the total thickness of the composite film reached 2.0 μm.

[0127] The specific composition parameters of the tungsten disulfide thin film samples are shown in Table 1.

[0128] The tungsten disulfide thin film prepared after the above deposition treatment was subjected to the following tests:

[0129] (1) The thickness of the film was tested using a scanning electron microscope.

[0130] (2) Using a nanoindentation instrument The nanohardness and elastic modulus of the film were measured. Six different regions were collected for each sample, with an indentation depth of 500 nm. The average value was calculated, and the results of the coating hardness and elastic modulus are shown in Table 2.

[0131] (4) The bonding performance of the film was tested using the Revetest scratch test system (CSM, Revetest). Three scratch tests were performed at different locations. The experimental conditions were: loading speed: 3 mm / min, scratch length: 5 mm, and loading force: 20 N. The test results are shown in Table 2.

[0132] (5) A friction testing machine (TRB3) was used to conduct reciprocating dry friction tests on films that had not undergone annealing and those that had undergone annealing at different temperatures and thermal vacuum testing under atmospheric conditions. The tests were repeated 2-3 times. 316L steel balls were used as the test material, and a reciprocating sliding method was adopted with a frequency of 5Hz, a track length of 5mm, a running distance of 90m, and a normal load of 5N. The wear cross-section was obtained using a surface profilometer (ASTQ), and the wear volume was obtained by multiplying it by the running step length. The wear rate was obtained by dividing the wear volume by the load and the stroke. The results of the friction coefficient and wear rate are shown in Tables 3 and 4, respectively.

[0133] Comparative Example 2

[0134] The method is the same as in Example 4, except that the tungsten disulfide / nickel target is missing.

[0135] Comparative Example 3

[0136] The method is the same as in Example 4, except that the tungsten disulfide / copper target is missing.

[0137] Comparative Example 4

[0138] The method is the same as in Example 4, except that the Ni and Cu content in the tungsten disulfide / copper target is increased, and the atomic ratio of the target material is increased from 70:30% to 50:50%.

[0139] Table 1: Compositional parameters of thin film samples

[0140]

[0141] Six points, each 500 nm deep, were indented into the surface of five thin film samples using a nanoindentation device. Hardness and elastic modulus were measured, and the results are shown in Table 2. Table 2 shows that the hardness of four tungsten disulfide-based doped soft metal composite films is no less than 6.5 GPa, with WS2-Ni-Cu-3 exhibiting the best mechanical properties.

[0142] Figure 1 This is a cross-sectional SEM image of the WS2-Ni-Cu-3 thin film prepared in Example 3 of the present invention.

[0143] Figure 2 This is a morphological diagram of the bonding force of the WS2-Ni-Cu-3 thin film obtained in Example 3 of the present invention.

[0144] Figure 3 These are test graphs of the hardness and elastic modulus of the WS2-Ni-Cu-3 thin film prepared in Example 3 of this invention.

[0145] Table 2: Hardness and Elastic Modulus of Thin Film Samples

[0146]

[0147]

[0148] The coefficients of friction and wear rates of the eight thin films under atmospheric conditions are shown in Table 3. WS2-Ni-Cu-3 in Example 3 exhibits the best coefficient of friction.

[0149] Figure 4 This is a friction curve of the WS2-Ni-Cu-3 thin film prepared in Example 3 of the present invention after annealing at room temperature, high temperature of 600℃, and thermal vacuum test.

[0150] Table 3: Friction and Wear Table of Thin Film Samples under Atmospheric Environment

[0151]

[0152] The coefficients of friction and wear rates of the eight thin films under alternating high and low temperatures and at different temperatures are shown in Table 4. WS2-Ni-Cu-3 in Example 3 exhibits the lowest coefficient of friction.

[0153] Figure 5 This is a wear rate diagram of the WS2-Ni-Cu-3 thin film prepared in Example 3 of the present invention after annealing at room temperature, high temperature of 600℃, and thermal vacuum test.

[0154] Table 4: Friction and wear of WS2-Ni-Cu-3 thin film samples under high and low temperature alternation and at different temperatures.

[0155]

[0156]

[0157] In summary, the composite film provided by this invention has good hardness (not less than 6.5 GPa) and elastic modulus, a bonding force of 20 N, and a friction coefficient of 0.04 after heat treatment at 600℃. It exhibits good tribological properties under alternating atmospheric conditions and in different temperature and humidity environments, and has good temperature self-adaptation and high-temperature oxidation resistance. It can meet the requirements of stable lubrication and long service life of aerospace vehicles.

[0158] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0159] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A soft metal-doped tungsten disulfide-based composite thin film, characterized in that, include: A titanium transition layer, a titanium / tungsten disulfide / nickel / copper gradient layer, and a tungsten disulfide / nickel / copper layer are sequentially formed on the surface of the substrate; In the titanium / tungsten disulfide / nickel / copper gradient layer, the content of titanium gradually decreases, the content of tungsten disulfide gradually increases, the content of nickel gradually increases, and the content of copper gradually increases along the direction gradually moving away from the substrate; at the same time, the tungsten disulfide / nickel / copper layer is formed by alternating layers of nickel-tungsten disulfide layer and copper-tungsten disulfide layer. The soft metal-doped tungsten disulfide-based composite film contains 8-12 at% nickel atoms and 1-4 at% copper atoms. The hardness of the composite film is greater than 6.5 GPa; The method for preparing the soft metal-doped tungsten disulfide-based composite thin film includes: Magnetron sputtering technology was employed, using a titanium target as the cathode and an inert gas as the working gas. A target current was applied to the titanium target, and a negative bias voltage was applied to the substrate, thereby depositing a titanium transition layer on the substrate surface. The target current was 3.0–5.0 A, the substrate bias voltage was -70–-100 V, the working gas flow rate was 30–35 sccm, the substrate temperature was 80–120 °C, and the reaction chamber pressure was 1.0–3.0 × 10⁻⁶. -3 The deposition time is 600-900 s; wherein the inert gas includes argon. Magnetron sputtering technology was employed, using titanium, tungsten disulfide / nickel, and tungsten disulfide / copper targets as cathode targets, and an inert gas as the working gas. Target currents were applied to the titanium, tungsten disulfide / nickel, and tungsten disulfide / copper targets, while a negative bias was applied to the substrate, thereby depositing a titanium / tungsten disulfide / nickel / copper gradient layer on the surface of the titanium transition layer. Specifically, the target current applied to the titanium target gradually decreased from 3.0–5.0 A to 0, the target current applied to the tungsten disulfide / nickel target gradually increased from 0 to 0.8–1.6 A, and the target current applied to the tungsten disulfide / copper target gradually increased from 0 to 0.8–1.6 A. The substrate bias was -30 to -70 V, the working gas flow rate was 30–35 sccm, the substrate temperature was 80–120 °C, and the reaction chamber pressure was 1.0–3.0 × 10⁻⁶. -3 The deposition time is 600-900 s; wherein the inert gas includes argon. Furthermore, using magnetron sputtering technology, with tungsten disulfide / nickel and tungsten disulfide / copper targets as cathode targets and inert gas as working gas, a target current is applied to the tungsten disulfide / nickel and tungsten disulfide / copper targets, and a negative bias voltage is applied to the substrate. A tungsten disulfide / nickel / copper layer is deposited on the surface of the titanium / tungsten disulfide / nickel / copper gradient layer to obtain a soft metal-doped tungsten disulfide-based composite thin film. The target current applied to the tungsten disulfide / nickel target is 0.8~1.6A, the target current applied to the tungsten disulfide / copper target is 0.8~1.6A, the substrate bias voltage is -30~-70V, the working gas flow rate is 30~35sccm, the substrate temperature is 80~120℃, and the reaction chamber pressure is 1.0~3.0×10⁻⁶. -3 The deposition time for the tungsten disulfide / nickel / copper layer is 9900~10300s; wherein the inert gas includes argon.

2. The composite film according to claim 1, characterized in that: The thickness of the titanium transition layer is 100~200nm; and / or, the thickness of the titanium / tungsten disulfide / nickel / copper gradient layer is 100~300nm; and / or, the thickness of the tungsten disulfide / nickel / copper layer is 1.5~2.5μm; and / or, the thickness of the composite film is 1.5~3.0μm.

3. The composite film according to claim 1, characterized in that: The substrate material includes any one of 316L, 9Cr18, and monocrystalline silicon.

4. The composite film according to claim 1, characterized in that, The method for preparing the composite film further includes: evacuating the reaction chamber to a vacuum level of 3 × 10⁻⁶. -5 Below torr, the substrate surface is first cleaned and then subjected to plasma etching treatment; wherein, the conditions of the plasma etching treatment include: applying a bias voltage of -400~-500V to the substrate, a substrate temperature of 100~150℃, and an etching time of 1200~1800s.

5. The application of the soft metal-doped tungsten disulfide-based composite thin film according to any one of claims 1-4 in the field of surface protection of aerospace devices in high-temperature environments or alternating high and low temperature environments; wherein, The materials used in the aerospace devices include 316L, 9Cr18, or monocrystalline silicon wafers.

6. An apparatus comprising a substrate, characterized in that: The substrate is further provided with a soft metal-doped tungsten disulfide-based composite film as described in any one of claims 1-4; wherein the material of the substrate includes 316L, 9Cr18 or a single crystal silicon wafer; the device includes an aerospace vehicle.

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