Method for making tungsten-doped diamond-like carbon film super-slippery and application thereof

Abstract

The application discloses a method for realizing super-slippery of tungsten-doped diamond-like carbon film and application thereof, and belongs to the technical field of friction lubrication. The method comprises the following steps: S1, tungsten-doped diamond-like carbon film is prepared on a substrate by using co-sputtering; and S2, molybdenum disulfide is deposited on the surface of the film to form a molybdenum disulfide-tungsten-doped diamond-like carbon composite film. The application further discloses a MoS2 / W-DLC super-slippery composite film prepared by the method and application thereof. The application combines magnetron co-sputtering and surface deposition, does not need to use flammable and explosive gas, and is safe, simple and convenient in process. The prepared composite film realizes stable super-low friction and super-slippery state under a load of 5N-15N in nitrogen, argon, oxygen and humid air with a relative humidity of not higher than 10%. The composite film has high bearing capacity and extremely low friction, overcomes the defect that single tungsten-doped diamond-like carbon film is difficult to realize super-slippery, and can be used in the fields of solid lubrication, mechanical sealing, precision devices, aerospace equipment and the like.

Description

Technical Field

[0001] This invention relates to the field of friction lubrication technology, specifically to a method and application for achieving superlubricity in tungsten-doped diamond-like thin films. Background Technology

[0002] Friction and wear are widespread in various mechanical equipment and industrial applications, causing significant energy and material losses, reducing equipment lifespan, and increasing operating costs. Therefore, reducing the coefficient of friction and minimizing wear has become a core research direction in mechanical engineering, surface engineering, and other fields. Superlubricity can significantly reduce frictional loss and is a key technological path to achieving efficient energy saving and long-life lubrication.

[0003] Currently, superlubricity is mainly achieved through two methods: liquid lubrication and solid lubrication. Among them, solid lubrication is more suitable for high-end equipment, precision devices, vacuum, and extreme environments because it is not limited by operating conditions and has a wider applicable temperature and environmental range. Tungsten-doped diamond-like carbon (W-DLC) films combine high hardness, excellent corrosion resistance, and wear resistance, making them a highly promising candidate material for solid lubrication. However, pure tungsten-doped diamond-like carbon films are difficult to stably achieve superlubricity, which limits their application in low-friction scenarios.

[0004] Existing superlubricating films are mostly prepared using chemical vapor deposition (CVD), a process with significant drawbacks: the preparation process requires the use of flammable and explosive gases such as methane and hydrogen, posing a high risk of leakage and potential explosions; furthermore, it demands stringent precision in equipment and specifications for components, resulting in complex process control and high equipment investment costs, which severely restricts the large-scale production and practical application of superlubricating films. Therefore, developing a safe, simple, and low-cost method that can stably achieve superlubricity in tungsten-doped diamond-like carbon (TDLC) films is of great practical significance for promoting the engineering application of low-friction solid lubrication technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and application for achieving superlubricity in tungsten-doped diamond-like films. The method involves preparing tungsten-doped diamond-like films by co-sputtering and depositing molybdenum disulfide, which does not require flammable or explosive hazardous gases and is safe and simple. The resulting composite film achieves stable ultra-low friction under wide loads and various atmospheres, and has both high load-bearing capacity and extremely low friction characteristics, thus overcoming the defect that single films are difficult to achieve superlubricity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for achieving superlubricity in tungsten-doped diamond-like thin films includes the following steps:

[0008] S1, tungsten-doped diamond-like thin films were prepared on a substrate by co-sputtering;

[0009] S2, molybdenum disulfide is deposited on the surface of the tungsten-doped diamond-like film to form a molybdenum disulfide-tungsten-doped diamond-like film composite film.

[0010] Furthermore, in step S1, the cavity is evacuated, argon gas is introduced, and a bias voltage of not less than 500V is applied to the substrate and target for cleaning; the carbon target power is set to 220-260W, the tungsten target power is set to 4-6W, and the sputtering time is 2h~5h.

[0011] Furthermore, the substrate is a single-crystal silicon or steel substrate, and the target material used is a graphite target or a tungsten target.

[0012] 4. A method for achieving superlubricity of tungsten-doped diamond-like thin films according to claim 3, characterized in that, in step S2, the deposition thickness of molybdenum disulfide is 10 μm to 30 μm.

[0013] Furthermore, in step S2, the molybdenum disulfide is a dispersion, which is first ultrasonically treated for 20 minutes, and its concentration is 50 mg / mL.

[0014] On the other hand, the present invention also provides a MoS2 / W-DLC superlubricating composite film prepared by the above method, characterized in that the composite film is composed of a tungsten-doped diamond-like carbon layer and a molybdenum disulfide layer covering thereon, wherein the thickness of the molybdenum disulfide layer is 10 μm to 30 μm.

[0015] Furthermore, when the composite film is rubbed against an Al2O3 ball under a load of 5N to 15N in nitrogen, argon, oxygen, dry air or humid air with a relative humidity of not more than 10%, the coefficient of friction in the stable stage is ≤0.010.

[0016] In another aspect, the present invention also provides the application of the above-mentioned MoS2 / W-DLC superlubricating composite film in solid lubrication, mechanical seals, precision devices or aerospace equipment.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The method provided by this invention uses co-sputtering technology to prepare tungsten-doped diamond-like carbon thin films and deposits molybdenum disulfide on their surface to form a composite film. The entire preparation process does not require the use of flammable and explosive gases such as methane and hydrogen, completely avoiding the safety hazards of gas leakage and explosion caused by traditional chemical vapor deposition (CVD) technology. This method is simple to operate, has a wide process window, and is highly safe, significantly reducing the threshold for industrial production of superlubricating thin films.

[0019] (2) Pure tungsten-doped diamond-like carbon (DLC) films cannot achieve superlubricity, but the MoS2 / W-DLC composite film prepared by depositing molybdenum disulfide on its surface can stably achieve superlubricity under loads of 5N to 15N (friction coefficient ≤0.010 in the stable stage). In various atmospheres such as nitrogen, argon, oxygen, and humid air, the composite film exhibits low friction characteristics close to superlubricity, overcoming the defect of single solid lubricating materials being sensitive to working conditions, and is suitable for complex and variable practical application environments.

[0020] (3) The target material and molybdenum disulfide used in this invention are common industrial materials, widely available and easy to obtain, and their composition is easy to control. Compared with the CVD process that relies on high-purity flammable gas and precision equipment, this method has lower requirements for instruments and equipment, significantly reduces material and process costs, and has higher process tolerance, which is conducive to the low-cost, mass production and engineering promotion of super-lubricating solid lubricating films. Attached Figure Description

[0021] Figures 1-8 The graph shows the friction curves of the MoS2 / W-DLC prepared in Example 1 under different loads.

[0022] Figures 9-11 The graphs show the friction curves of the MoS2 / W-DLC prepared in Example 1 under different atmospheres.

[0023] Figure 12 , 13 The graph shows the tribological curves of the MoS2 / W-DLC prepared in Example 1 under different humidity conditions.

[0024] Figures 14-19 The following are friction curves of the W-DLC prepared in the comparative example under different loads;

[0025] Figures 20-22 The image shows the friction curves of the W-DLC prepared in the comparative example under different atmospheres. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0027] This application provides a method for achieving superlubricity in tungsten-doped diamond-like thin films, the specific steps of which are as follows:

[0028] S1. The cavity is evacuated, argon gas is introduced into the cavity, and a bias voltage is applied to the substrate (single-crystal silicon or steel substrate) and all targets (graphite target and tungsten target) for cleaning. The sputtering power is set, and a uniform and dense tungsten-doped diamond-like carbon film is prepared by co-sputtering. The bias voltage is not less than 500V; the carbon target power is 220-260W, the tungsten target power is 4-6W, and the co-sputtering time is 2h~5h.

[0029] S2, take molybdenum disulfide with a concentration of 50 mg / mL, sonicate for 20 min to obtain a molybdenum disulfide dispersion, drop 3-10 drops of the molybdenum disulfide dispersion onto the surface of the above tungsten-doped diamond-like carbon film, irradiate for 5-15 min, evaporate the solvent to deposit molybdenum disulfide, forming a composite film structure. The thickness of the molybdenum disulfide coating is controlled between 10 μm and 30 μm.

[0030] The molybdenum disulfide-tungsten doped diamond-like composite film prepared by the above method can stably achieve superlubricity under high load, various atmospheres, and various humidity environments.

[0031] Example 1

[0032] The method for achieving superlubricity in tungsten-doped diamond-like carbon films provided in this embodiment is as follows:

[0033] S1, the cavity is evacuated to a vacuum level of 5×10⁻⁶. -3 After continuously introducing argon gas at a flow rate of 60 sccm, the substrate and target were cleaned by applying a bias voltage of 700V. The carbon target power was set to 250W and the tungsten target power was set to 5W. After co-sputtering for 5 hours, a uniform and dense tungsten-doped diamond-like carbon film (W-DLC) was finally formed.

[0034] S2, take molybdenum disulfide with a concentration of 50 mg / mL, sonicate for 20 min to obtain molybdenum disulfide dispersion, drop 5 drops of molybdenum disulfide dispersion onto the surface of tungsten-doped diamond-like carbon film, irradiate for 10 min and the solvent evaporates to form composite material MoS2 / W-DLC; the thickness of the molybdenum disulfide coating is 20 μm.

[0035] The MoS2 / W-DLC composite material prepared above was subjected to the following performance tests:

[0036] (1) Friction experiments were conducted in N2 at a frequency of 5 Hz under loads ranging from 3 N to 17 N, with a duration of 20 min and a stroke of 5 mm. The friction curves of MoS2 / W-DLC under different loads are shown in the figure. Figures 1-8 As shown in the figure, the composite material prepared in this embodiment can still achieve a super-lubricated state under a high load of 15N.

[0037] (2) Friction experiments were conducted on the MoS2 / W-DLC in N2, Ar, and O2 atmospheres at a frequency of 5 Hz under a load of 7 N for 20 min and a stroke of 5 mm. The friction curves of MoS2 / W-DLC under different atmospheres are shown in the figure. Figures 9-11 As shown in the figure, the MoS2 / W-DLC composite material prepared in this embodiment can approach a superlubricated state under an inert atmosphere and also has a low coefficient of friction under an O2 atmosphere.

[0038] (3) Friction experiments were conducted with Al2O3 balls under a load of 7N and at a frequency of 5Hz in both dry and 10% humidity conditions for 20 minutes, with a stroke of 5mm. The friction curves of MoS2 / W-DLC under different humidity conditions are shown in the figure. Figure 12 , 13 As shown in the figure, it is close to a super-slippery state whether in a dry state or in air with a humidity of 10%.

[0039] Example 2

[0040] The method for achieving superlubricity in tungsten-doped diamond-like carbon films provided in this embodiment is as follows:

[0041] S1, the cavity is evacuated to a vacuum level of 5×10⁻⁶. -3 After continuously introducing argon gas at a flow rate of 60 sccm, the substrate and target were cleaned by applying a bias voltage of 600V. The carbon target power was set to 220W and the tungsten target power was set to 4W. After co-sputtering for 5 hours, a uniform and dense tungsten-doped diamond-like carbon film (W-DLC) was finally formed.

[0042] S2, using 50 mg / mL molybdenum disulfide after 20 min of sonication, was deposited on the surface of a tungsten-doped diamond-like carbon film to form a composite material MoS2 / W-DLC; the thickness of the molybdenum disulfide coating was 15 μm.

[0043] Example 3

[0044] The method for achieving superlubricity in tungsten-doped diamond-like carbon films provided in this embodiment is as follows:

[0045] (1) Evacuate the cavity to 5×10 -3 After continuously introducing argon gas at a flow rate of 60 sccm, the substrate and target were cleaned by applying a bias voltage of 800V. The carbon target power was set to 260W and the tungsten target power was set to 6W. After co-sputtering for 5 hours, a uniform and dense tungsten-doped diamond-like carbon film (W-DLC) was finally formed.

[0046] (2) MoS2 / W-DLC composite material was formed by depositing 50 mg / mL molybdenum disulfide on the surface of a tungsten-doped diamond-like film after 20 min of sonication; the thickness of the molybdenum disulfide coating was 15 μm.

[0047] Comparative Example

[0048] Based on Example 1, tungsten-doped diamond-like carbon (W-DLC) films were prepared using the method in step S1 without the deposition of molybdenum disulfide. The prepared W-DLCs were subjected to the following performance tests:

[0049] (1) Friction experiments were conducted in N2 at a frequency of 5 Hz under loads ranging from 3 N to 13 N, with a contact time of 20 min and a stroke of 5 mm. The friction curves of W-DLC under different loads are shown in the figure. Figures 14-19 As shown in the figure, it is clear that it has not reached the super-slippery state.

[0050] (2) Friction experiments were conducted on the W-DLC in N2, Ar, and O2 atmospheres at a frequency of 5 Hz under a load of 7 N. The contact time was 20 min and the stroke was 5 mm. The friction curves of W-DLC under different atmospheres are shown in the figure. Figure 20 , Figure 21 , Figure 22 As shown in the figure, W-DLC under different atmospheres did not reach the superlubricating state.

[0051] In addition, the performance test results in Example 1 and the performance test results in the comparative example are summarized in the table below:

[0052] Summary of performance test results

[0053]

[0054] As can be clearly seen from the table above, the friction coefficient of pure tungsten-doped diamond-like films without molybdenum disulfide deposition is significantly higher under various working conditions, failing to meet the superlubricity standard. In contrast, the MoS2 / W-DLC composite film modified with molybdenum disulfide surface can stably enter the superlubricity range under wide load, multiple atmospheres, and low humidity environments, with a friction coefficient far lower than that of the single W-DLC film. This fully verifies the effectiveness and reliability of the method of this invention in achieving superlubricity of tungsten-doped diamond-like films.

[0055] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A method for achieving superlubricity in tungsten-doped diamond-like thin films, characterized in that, Includes the following steps: S1, tungsten-doped diamond-like thin films were prepared on a substrate by co-sputtering; S2, molybdenum disulfide is deposited on the surface of the tungsten-doped diamond-like film to form a molybdenum disulfide-tungsten-doped diamond-like film composite film.

2. The method for achieving superlubricity in tungsten-doped diamond-like thin films according to claim 1, characterized in that, In step S1, the cavity is evacuated, argon gas is introduced, and a bias voltage of not less than 500V is applied to the substrate and target for cleaning; the carbon target power is set to 220-260W, the tungsten target power is set to 4-6W, and the sputtering time is 2h~5h.

3. The method for achieving superlubricity in tungsten-doped diamond-like thin films according to claim 2, characterized in that, The substrate is a monocrystalline silicon or steel substrate, and the target material is an ink target or a tungsten target.

4. The method for achieving superlubricity in tungsten-doped diamond-like thin films according to claim 3, characterized in that, In step S2, the deposition thickness of molybdenum disulfide is 10 μm to 30 μm.

5. The method for achieving superlubricity in tungsten-doped diamond-like thin films according to claim 4, characterized in that, In step S2, the molybdenum disulfide is a dispersion, which is first ultrasonically treated for 20 minutes and has a concentration of 50 mg / mL.

6. A MoS2 / W-DLC superlubricating composite film prepared by the method according to any one of claims 1 to 5, characterized in that, The composite film consists of a tungsten-doped diamond-like carbon layer and a molybdenum disulfide layer covering it, wherein the thickness of the molybdenum disulfide layer is 10 μm to 30 μm.

7. The MoS2 / W-DLC superlubricated composite film according to claim 6, characterized in that, When the composite film is rubbed against an Al2O3 ball under a load of 5N to 15N in nitrogen, argon, oxygen, dry air or humid air with a relative humidity of not more than 10%, the friction coefficient in the stable stage is ≤0.

010.

8. The application of the MoS2 / W-DLC superlubricating composite film according to claim 6 or 7 in solid lubrication, mechanical seals, precision devices or aerospace equipment.

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