A method for preparing an ultralubricating surface capable of withstanding extreme high contact pressure

Abstract

The application discloses a kind of superlubricated surface preparation method capable of tolerating extreme high contact pressure, belong to mechanical engineering lubrication technical field.The method includes: using ultra-short pulse laser etching system to form regular arrangement micro contact unit on substrate surface;Amorphous carbon lubricating film is deposited on the substrate surface after etching using vapor deposition technology, the amorphous carbon lubricating film covers the contact unit;MXene material is mixed with other two-dimensional lubricating material to form MXene-based hetero-compound, dispersed in solvent to prepare dispersion, sprayed on the surface of amorphous carbon lubricating film, dried to form MXene-based hetero-composite lubricating coating, the superlubricated surface is obtained.The application solves the problem that existing superlubrication technology is easy to fail under atmospheric environment and extreme high contact pressure by micro contact unit design, high hardness amorphous carbon film support and MXene-based hetero-compound lubrication cross-scale synergistic strategy.The prepared superlubricated surface can still maintain stable superlubrication state (friction coefficient <0.01) when contact pressure is up to 12.7 GPa in atmospheric environment, and the service life is more than 10 5 cycles, which has wide application prospect in aerospace, high-end equipment and other extreme working condition lubrication fields.

Description

Technical Field

[0001] This invention belongs to the field of mechanical engineering lubrication technology, specifically relating to a method for preparing a super-lubricating surface that can withstand extremely high contact pressure, in order to achieve super-lubricating performance of industrial machinery and equipment under extremely high contact pressure. Background Technology

[0002] Friction is one of the most common phenomena in nature, especially in mechanical systems, where friction and wear directly affect energy consumption, operational accuracy, reliability, and service life. Statistics show that approximately one-third of global primary energy consumption originates from friction, and about 80% of mechanical component failures are caused by wear. Therefore, developing advanced lubrication materials and technologies to achieve ultra-low coefficients of friction (i.e., super-lubricated states) at friction interfaces is of great significance for saving energy and extending equipment life.

[0003] Super-lubricated typically refers to a coefficient of friction as low as 10. -3 Lubrication conditions can be measured in orders of magnitude or even lower. Since the concept of superlubrication was proposed in the 1990s, researchers have observed superlubrication phenomena at the atomic, nanoscale, and even micrometer scales, and are gradually exploring the possibility of achieving superlubrication at the macroscopic scale. If superlubrication can be stably achieved under atmospheric conditions and actual engineering working conditions, it is expected to redefine key performance indicators of mechanical systems, such as energy consumption, accuracy, sensitivity, reliability, and lifespan.

[0004] Currently, material systems considered to have superlubricating potential mainly include two categories: two-dimensional layered materials (such as molybdenum disulfide MoS2 and graphene) and amorphous carbon lubricating films. The superlubricating mechanism of two-dimensional layered materials mainly relies on the weak van der Waals forces between their layers, achieving low friction through interlayer slippage during friction. The superlubricity of amorphous carbon films is mainly attributed to the passivation effect of hydrogen atoms on carbon dangling bonds on their surface, thereby reducing interfacial adhesion and tribochemical reactions.

[0005] However, the realization of existing superlubricity largely depends on idealized conditions, such as perfect material structure, clean contact interface, low contact pressure, and vacuum or inert gas environment, which severely restricts its engineering application. For example, Berman et al. reported that a composite system composed of graphene, nanodiamond particles, and amorphous carbon films achieved superlubricity in a nitrogen environment with a contact pressure of 0.3 GPa, but the superlubricity performance rapidly failed in an air environment. Science 2015, 348, 1118. Li et al. proposed a strategy of combining "microscopic superlubricity" to achieve "macroscopic superlubricity," realizing superlubricity with a contact pressure of 0.5 GPa in an inert environment on a MoS2 / Graphene heterostructure. Adv. Mater. 2020,32, 2002039).

[0006] Despite the significant progress made in the aforementioned research, current technologies still face the following key challenges: Under actual service conditions in industrial machinery, friction interfaces are often subjected to extremely high contact pressures (GPa level) and exposed to humid atmospheric environments. The coupling effect between these two factors leads to the failure of existing superlubrication mechanisms. Specifically, for two-dimensional layered materials, extremely high contact pressures may disrupt their layered slip structure, causing them to lose their superlubricating ability; for amorphous carbon thin films, water and oxygen molecules in the atmosphere readily undergo violent tribochemical reactions with the friction interface, disrupting the passivation state of carbon dangling bonds and leading to an increase in the coefficient of friction. Therefore, how to improve the tolerance of lubricating materials to extremely high contact pressures while overcoming atmospheric environmental sensitivity has become the core bottleneck in the current research on superlubrication, moving from theory to engineering application.

[0007] To address the aforementioned issues, there is an urgent need to develop a method for preparing superlubricating surfaces that can operate stably under atmospheric conditions and extreme high contact pressures (such as above 10 GPa) to meet the pressing demand for lubrication technology under extreme operating conditions in fields such as high-end equipment, aerospace, and precision manufacturing. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and address the current deficiency that industrial mechanical friction interfaces are difficult to obtain stable superlubricity under atmospheric environment and extreme high contact pressure. It provides a method for preparing a superlubricity surface that can withstand extreme high contact pressure, aiming to achieve stable superlubricity characteristics of the friction interface under extreme contact pressure conditions of up to 12.7 GPa in the atmospheric environment.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a superlubricating surface capable of withstanding extremely high contact pressure includes the following steps: (1) Surface microstructuring treatment: Multiple regularly arranged micro-contact units are formed on the surface of the substrate using an ultra-short pulse laser etching system; (2) Depositing an amorphous carbon lubricating film: Using vapor deposition technology, carbon-containing gas is used as the reaction gas, inert gas is used as the sputtering gas, and carbon target and metal target are used as sputtering targets to deposit an amorphous carbon lubricating film on the surface of the substrate after step (1), and the amorphous carbon lubricating film covers the contact unit. (3) Constructing a heterogeneous composite lubricating layer: Mix MXene material with other two-dimensional lubricating materials to form an MXene-based heterogeneous composite, and disperse the composite in a solvent to obtain a dispersion. Then spray the dispersion onto the surface of the amorphous carbon lubricating film obtained in step (2), and after drying, form an MXene-based heterogeneous composite lubricating coating, thus obtaining the super-lubricating surface.

[0010] In the technical solution of this invention, superlubricity under ultra-high contact pressure in an atmospheric environment is achieved through a cross-scale synergistic strategy from the macroscopic contact interface to the atomic lattice. This synergistic strategy is mainly based on the coupling effect of the following four key factors: First, a regularly arranged micro-contact unit is constructed on the substrate surface by ultrashort pulse laser etching, forming a normalized macroscopic contact interface. This microstructure design reduces the actual contact area and provides structural support for the subsequent lubrication layer, effectively dispersing interfacial contact stress.

[0011] Second, a high-hardness, high-hydrogen-content amorphous carbon lubricating film is deposited on the microstructured surface. This film not only provides rigid support for the top heterogeneous composite lubricating layer and suppresses interfacial deformation under high contact pressure, but also its surface hydrogen atoms can passivate carbon dangling bonds and reduce tribochemical reactivity.

[0012] Third, an MXene-based heterogeneous composite lubricating layer is constructed on the surface of an amorphous carbon thin film. MXene material has strong mechanical properties and layered structure stability, which plays a supporting and anchoring role under high contact pressure, and promotes other two-dimensional lubricating materials (such as MoS2, graphene, etc.) to maintain the complete layered structure during friction, avoiding superlubrication failure caused by the destruction of the layered slip structure.

[0013] Fourth, a stable incommensurate contact interface is formed between the amorphous carbon lubricating film and the MXene-based heteropolymer. This incommensurate contact state can effectively suppress energy dissipation at the friction interface, resulting in a significant reduction in the coefficient of friction.

[0014] The aforementioned cross-scale synergistic strategy can effectively overcome the problems of easy destruction of the layered structure of two-dimensional layered materials under high contact pressure and sensitivity to atmospheric environment in the existing technology. It can maintain a robust superlubricated state under extreme coupling conditions (millimeter-level contact size, atmospheric environment and GPa-level contact pressure).

[0015] As a preferred embodiment of the present invention, in step (1), the contact unit is a micron-level protrusion structure with a surface that is a square with a side length of 20-50 μm and a height of 1-5 μm, and the spacing between adjacent contact units is 5-20 μm. More preferably, after laser etching, the projected area of ​​the contact unit on the substrate surface accounts for less than 40 / 100 of the total surface area of ​​the substrate.

[0016] As a preferred technical solution of the present invention, in step (1), the substrate is steel, stainless steel or titanium alloy.

[0017] As a preferred technical solution of the present invention, in step (2), the hydrogen content of the amorphous carbon lubricating film is ≥33% and the hardness is ≥10 GPa.

[0018] As a preferred technical solution of the present invention, in step (2), the metal in the metal target is Ti, W or Si, and the atomic content of the doped metal in the amorphous carbon lubricating film is <15%, and the internal stress of the film is <0.4 GPa.

[0019] As a preferred technical solution of the present invention, in step (2), the deposition thickness of the amorphous carbon lubricating film is 1~5μm.

[0020] As a preferred technical solution of the present invention, in step (3), the other two-dimensional lubricating materials are MoS2, WS2, TaSe2, NbSe2, graphene or hexagonal boron nitride; the mass ratio of the MXene material to the other two-dimensional lubricating materials is 5:1 to 1:5.

[0021] As a preferred technical solution of the present invention, in step (3), the number of layers of the MXene material and other two-dimensional lubricating materials is less than 30; the concentration of the MXene-based heterogeneous compound dispersion is 2~14 g / L.

[0022] As a preferred technical solution of the present invention, in step (3), the thickness of the MXene-based heterogeneous composite lubricating coating is 10~50 μm.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. Excellent tolerance to extreme high contact pressure: The superlubricated surface prepared by this invention can still maintain a stable superlubricated state (friction coefficient <0.01) under atmospheric conditions and contact pressures as high as 12.7 GPa, which is far superior to the level of superlubricity that can usually only be achieved below 0.5 GPa in the prior art.

[0024] 2. Good adaptability to atmospheric environment: This invention overcomes the defects of traditional two-dimensional layered materials and amorphous carbon thin films that are prone to failure of super-lubricating performance in atmospheric environment, and achieves long-term stable super-lubricity in an atmospheric environment with a relative humidity of 20%.

[0025] 3. Long life and superior lubrication performance: such as Figure 4 As shown, the superlubricated surface prepared by this invention can maintain a superlubricated state for 1×10⁻⁶ days under a load of 20 N (corresponding to a contact pressure of 12.7 GPa). 5 It exhibits excellent durability after more than one friction cycle.

[0026] 4. High applicability: The method of this invention is applicable to a variety of commonly used engineering substrates such as steel, stainless steel, and titanium alloys, and has good prospects for industrial application.

[0027] 5. Clear mechanism: such as Figure 3As shown in the high-resolution transmission electron microscope image, the MXene-based heterocomposite prepared in this invention forms a flat, layered stacked structure during friction. This confirms that the supporting and anchoring effect of MXene enables other two-dimensional lubricating materials to maintain an intact layered structure under high contact pressure, thereby maintaining a stable non-commensurate contact state with the amorphous carbon lubricating film layer, providing a structural basis for super-lubricating performance.

[0028] In summary, this invention effectively solves the failure problem of existing superlubrication technologies under extreme high contact pressure and atmospheric environments through a cross-scale synergistic strategy of macroscopic contact interface design, rigid support layer construction, and heterogeneous composite lubrication layer optimization. It provides a feasible technical approach for structural superlubrication from an idealized model to practical engineering applications. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process for preparing the super-lubricated surface that can withstand extremely high contact pressure according to the present invention.

[0030] Figure 2 These are typical scanning electron microscope images of the surface morphology of the substrate after laser etching in Examples 1-3 of the present invention, where: a-Example 1, b-Example 2, c-Example 3.

[0031] Figure 3 This is a high-resolution transmission electron microscope image of the MXene-based heterocomplex prepared in Example 1 of the present invention after a tribological test.

[0032] Figure 4 The friction coefficient curves of the superlubricated surface prepared in Example 1 of the present invention under different loads are shown. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to these embodiments. All equivalent transformations or modifications made based on the above technical solutions of the present invention should fall within the scope of protection of the present invention.

[0034] Example 1 (1) Laser etching substrate preparation 316L stainless steel was selected as the substrate and ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 15 min each, followed by nitrogen drying. A regularly arranged micro-contact unit was constructed on the substrate surface using an ultrashort pulse laser etching system. Laser processing parameters: laser energy maintained at 5 kW, laser power set to 20%, scanning speed 500 mm / s, and pulse repetition frequency 100 kHz. After etching, an array of micron-sized protrusions was formed. Each contact unit surface is square, with a side length of approximately 25 μm and a height of approximately 3 μm, and the spacing between adjacent units is approximately 15 μm. Image analysis software calculations showed that the projected area of ​​the contact units on the substrate surface after laser processing accounts for approximately 20 / 100 of the total substrate surface area.

[0035] (2) Deposition of amorphous carbon lubricating thin film Thin film deposition was performed using a magnetron sputtering deposition machine equipped with four target positions. The etched substrate was mounted on a sample holder, and the deposition chamber was evacuated to a base vacuum of 3 × 10⁻⁶. -4 Pa. The substrate underwent glow discharge cleaning for 15 min at a cleaning bias of -500 V. Deposition process: Two Ti targets (99.9% purity) were mounted at two target sites and connected to a pulsed sputtering power supply (50 kHz); two C targets (99.99% purity) were mounted at two target sites and also connected to a pulsed sputtering power supply (50 kHz); the sample holder was connected to a pulsed bias power supply (50 kHz). First, a Ti transition layer was deposited: Ar gas flow rate 50 sccm, working pressure 0.5 Pa, Ti target sputtering power 5 W / cm. 2 The substrate bias was -60V, the deposition time was 10 min, and the transition layer thickness was approximately 100 nm. Then, an amorphous carbon lubricating film was deposited: CH4 gas was introduced as the reactant gas, and Ar gas was used as the sputtering gas, with a CH4 / Ar flow ratio of 5:1, an operating pressure of 0.8 Pa, and a C target sputtering power of 8 W / cm². 2 Ti target sputtering power 5 W / cm 2 The substrate bias was -80 V, and the deposition time was 120 min. Characterization showed that the prepared amorphous carbon lubricating film had a hydrogen content of 33%, a hardness of 20 GPa, a Ti atomic content of 2.1% (X-ray photoelectron spectroscopy analysis), an internal stress of 0.25 GPa (curvature method test), and a total film thickness of approximately 3.1 μm.

[0036] (3) Preparation of MXene-based heterogeneous complex dispersion Weigh out Ti3C2T xMXene (approximately 30 layers) and molybdenum disulfide (MoS2) (approximately 10 layers) were mixed at a mass ratio of 1:1, with a total mass of 2 g. The mixed powder was added to 200 mL of anhydrous ethanol to prepare a dispersion with a concentration of 10 g / L. The dispersion was then subjected to high-speed resonance dispersion using a hummingbird resonance apparatus at a resonance frequency of 60 Hz, a resonance acceleration of 80 g, and a resonance time of 45 min, resulting in a uniform and stable MXene / MoS2 heteropolymer dispersion.

[0037] (4) Spraying to construct a heterogeneous composite lubrication layer The etched substrate with the amorphous carbon film deposited in step (2) was fixed on a heating platform, with the platform temperature controlled at 50°C. The dispersion prepared in step (3) was uniformly sprayed onto the substrate surface using a spray gun (0.5 mm nozzle) under dry compressed air carrier gas. The spraying pressure was 0.2 MPa, the spraying distance was 15 cm, and the spraying was repeated 3 times. After spraying, the sample was placed in a drying oven at room temperature for 12 hours to surface dry, and then dried in a vacuum drying oven at 60°C for 2 hours. The thickness of the obtained MXene-based heterogeneous composite lubricating coating was approximately 30 μm, as measured by a MINITEST 1100 thickness gauge.

[0038] (5) Tribological property testing The tribological properties of the prepared superlubricated surface were tested under different loads using a CSM ball-disc friction and wear testing machine. The mating balls were 9Cr18 steel balls (3 mm in diameter), operating in a reciprocating linear motion mode with a stroke of 5 mm and a frequency of 6.37 Hz. The ambient temperature was 25℃ and the relative humidity was 20%. Tests were conducted under loads of 5 N, 10 N, 15 N, 20 N, 25 N, and 30 N, with a new mating ball placed before each load test. The test results are shown in Table 1 below. Table 1. Tribological properties of the coating prepared in Example 1 under different atmospheric loads. Finite element analysis showed that the average contact pressure at the interface under a 20N load was 12.7 GPa. Figure 4 As shown, under this extremely high contact pressure, the coefficient of friction remains stable below 0.01, and the super-lubricated state can be maintained at 1×10⁻⁶. 5 After more than one friction cycle, it exhibits excellent tolerance to extreme high contact pressure and long-term stability.

[0039] The samples after the friction test were analyzed by high-resolution transmission electron microscopy, and the results are as follows: Figure 3As shown in the figure, the MXene-based heteropolymer complex forms a flat, layered structure during the slippage process, with MXene and MoS2 exhibiting a regular layered stacking characteristic. This indicates that the multilayered MXene plays a strong supporting and anchoring role, enabling MoS2 to maintain its intact layered structure even under extremely high contact pressure, thereby maintaining the incommensurate contact state with the amorphous carbon lubricating film and providing a structural basis for the superlubricating performance.

[0040] Example 2 (1) Laser etching substrate preparation TC4 titanium alloy was selected as the substrate, and the cleaning method was the same as in Example 1. Laser processing parameters: laser energy maintained at 10kW, laser power set to 50%, scanning speed 300 mm / s, and pulse repetition frequency 100 kHz. After etching, regularly arranged micro-contact units were formed. Each contact unit had a square surface with a side length of approximately 28 μm and a height of approximately 4 μm, with a spacing of approximately 10 μm between adjacent units. After laser processing, the projected area of ​​the contact units on the substrate surface accounted for approximately 30 / 100 of the total surface area of ​​the substrate.

[0041] (2) Deposition of amorphous carbon lubricating thin film The same magnetron sputtering equipment as in Example 1 was used, the difference being that a W target (99.9% purity) was selected as the metal target. Deposition process: First, a W transition layer was deposited, with a W target sputtering power of 12 W / cm². 2 Ar gas flow rate 50 sccm, working pressure 0.5 Pa, substrate bias -80 V, deposition time 8 min, transition layer thickness approximately 100 nm. Then, an amorphous carbon lubricating film was deposited: CH4 / Ar flow ratio 10:1, working pressure 0.8 Pa, C target sputtering power 10 W / cm². 2 W target sputtering power 12 W / cm 2 The substrate bias was -100V, and the deposition time was 150 min. Characterization showed that the prepared amorphous carbon lubricating film had a hydrogen content of 35%, a hardness of 15 GPa, a W doping atomic content of 1.8%, an internal stress of 0.35 GPa, and a total film thickness of approximately 3.5 μm.

[0042] (3) Preparation of MXene-based heterogeneous complex dispersion Weigh out Ti3C2T x MXene (approximately 15 layers) and graphene (approximately 10 layers) were mixed at a mass ratio of 5:1, with a total mass of 0.6 g. The mixed powder was added to 100 mL of anhydrous ethanol to prepare a dispersion with a concentration of 6 g / L. Dispersion was carried out using the same resonance dispersion process as in Example 1.

[0043] (4) Spraying to construct a heterogeneous composite lubrication layer Using the same spraying method as in Example 1, the dispersion was sprayed onto the surface of an etched substrate with a deposited amorphous carbon film, and the number of spraying passes was controlled to be 2. After drying, the thickness of the MXene-based heterogeneous composite lubricating coating was measured to be approximately 20 μm.

[0044] (5) Tribological property testing The test conditions were the same as in Example 1, and the results are shown in Table 2 below: Table 2. Tribological properties of the coating prepared in Example 2 under different atmospheric loads. Example 3 (1) Laser etching substrate preparation GCr15 bearing steel was selected as the substrate, and the cleaning method was the same as in Example 1. Laser processing parameters: laser energy maintained at 15kW, laser power set to 35%, scanning speed 400 mm / s, and pulse repetition frequency 100 kHz. After etching, regularly arranged micro-contact units were formed. Each contact unit had a square surface with a side length of approximately 30 μm and a height of approximately 2 μm, with a spacing of approximately 7 μm between adjacent units. After laser processing, the projected area of ​​the contact units on the substrate surface accounted for approximately 40 / 100 of the total surface area of ​​the substrate.

[0045] (2) Deposition of amorphous carbon lubricating thin film The same magnetron sputtering equipment as in Example 1 was used, the difference being that a Si target (99.99% purity) was selected as the metal target. Deposition process: First, a Si transition layer was deposited, with a Si target sputtering power of 25 W / cm². 2 Ar gas flow rate 50 sccm, working pressure 0.5 Pa, substrate bias -100 V, deposition time 6 min, transition layer thickness approximately 100 nm. Then, an amorphous carbon lubricating film was deposited: CH4 / Ar flow ratio 8:1, working pressure 0.8 Pa, C target sputtering power 15 W / cm². 2 Si target sputtering power 25 W / cm 2 The substrate bias was -120 V, and the deposition time was 120 min. Characterization showed that the prepared amorphous carbon lubricating film had a hydrogen content of 34%, a hardness of 13 GPa, an atomic content of 2.5% Si doping, an internal stress of 0.3 GPa, and a total film thickness of approximately 2.9 μm.

[0046] (3) Preparation of MXene-based heterogeneous complex dispersion Weigh out Ti3C2T xMXene (approximately 20 layers) and niobium diselenide (NbSe2) (approximately 20 layers) were mixed at a mass ratio of 1:5, with a total mass of 0.6 g. The mixed powder was added to 50 mL of anhydrous ethanol to prepare a dispersion with a concentration of 12 g / L. Dispersion was carried out using the same resonance dispersion process as in Example 1.

[0047] (4) Spraying to construct a heterogeneous composite lubrication layer Using the same spraying method as in Example 1, the dispersion was sprayed onto the surface of an etched substrate with a deposited amorphous carbon film, with the number of spraying cycles controlled to be 1. After drying, the thickness of the MXene-based heterogeneous composite lubricating coating was measured to be approximately 10 μm.

[0048] (5) Tribological property testing The test conditions were the same as in Example 1, and the results are shown in Table 3 below: Table 3. Tribological properties of the coating prepared in Example 3 under different atmospheric loads. Comparative Example 1 To verify the effect of the microstructuring treatment of the present invention, this comparative example was set up. Except for omitting the laser etching treatment in step (1) and directly performing steps (2) and (3) on the polished 316L stainless steel substrate, the other process parameters were exactly the same as in Example 1. Tribological performance tests showed that: after depositing an amorphous carbon lubricating film on the surface of a smooth substrate and then spraying an MXene-based heterogeneous composite lubricating coating, the friction coefficient showed a trend of first gradually decreasing and then gradually increasing with the increase of the applied load, while the wear life gradually decreased with the increase of the load.

[0049] Table 4. Tribological properties of the coating prepared in Comparative Example 1 under different atmospheric loads. Comparative Example 2 To verify the effect of the MXene-based heterogeneous composite lubricating layer of the present invention, this comparative example was set up. Except for omitting step (3) and only performing friction tests on the surface of the amorphous carbon lubricating film prepared in step (2), the other process parameters were exactly the same as in Example 1. Tribological performance tests showed that: when friction experiments were conducted on the surface of the amorphous carbon lubricating film deposited on the substrate after laser etching, the coefficient of friction gradually decreased with the increase of the applied load, and the wear life gradually decreased with the increase of the load.

[0050] Table 5. Tribological properties of the coatings prepared in Comparative Example 2 under different atmospheric loads. Comparative Example 3 To verify the crucial role of MXene support in this invention, a comparative example was set up. Except for step (3), which uses only MoS2 without adding MXene to prepare the dispersion, the other process parameters were exactly the same as in Example 1. Tribological performance tests showed that after depositing an amorphous carbon lubricating film on the surface of the substrate after laser etching and spraying a single-component MoS2 solid lubricant, friction experiments were conducted. As the applied load increased, the coefficient of friction gradually decreased, and the wear life gradually decreased with the increase of the load.

[0051] Table 6. Tribological properties of the coating prepared in Comparative Example 3 under different atmospheric loads. In summary, this invention successfully fabricates a superlubricated surface capable of withstanding extremely high contact pressures through a cross-scale synergistic strategy: laser etching to construct micro-contact units, deposition of a high-hardness amorphous carbon lubricating film as a rigid support layer, and spraying of an MXene-based heteropolymer as a lubricating layer. This surface maintains a stable superlubricated state even under atmospheric conditions and contact pressures as high as 12.7 GPa, with a friction coefficient below 0.01 and a lifetime exceeding 1 × 10⁻⁶. 5 This cycle provides a feasible solution for the engineering application of superlubrication technology under extreme working conditions.

Claims

1. A method for preparing a superlubricating surface capable of withstanding extremely high contact pressure, characterized in that, Includes the following steps: (1) Surface microstructuring treatment: Multiple regularly arranged micro-contact units are formed on the surface of the substrate using an ultra-short pulse laser etching system; (2) Depositing an amorphous carbon lubricating film: Using vapor deposition technology, carbon-containing gas is used as the reaction gas, inert gas is used as the sputtering gas, and carbon target and metal target are used as sputtering targets to deposit an amorphous carbon lubricating film on the surface of the substrate after step (1), and the amorphous carbon lubricating film covers the contact unit. (3) Constructing a heterogeneous composite lubricating layer: MXene material is compounded with other two-dimensional lubricating materials at a mass ratio of 5:1 to 1:5 to form an MXene-based heterogeneous composite. The composite is dispersed in a solvent to obtain a dispersion. The dispersion is then sprayed onto the surface of the amorphous carbon lubricating film obtained in step (2). After drying, an MXene-based heterogeneous composite lubricating coating is formed, which is the super-lubricating surface.

2. The preparation method according to claim 1, characterized in that, In step (1), the contact unit is a micron-level protrusion structure with a surface that is a square with a side length of 20~50 μm and a height of 1~5 μm. The spacing between adjacent contact units is 5~20 μm.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), after laser etching, the projected area of ​​the contact unit on the substrate surface accounts for less than 40 / 100 of the total surface area of ​​the substrate.

4. The preparation method according to claim 1, characterized in that, In step (1), the substrate is steel, stainless steel or titanium alloy.

5. The preparation method according to claim 1, characterized in that, In step (2), the hydrogen content of the amorphous carbon lubricating film is ≥33%, and the hardness is ≥10 GPa.

6. The preparation method according to claim 1 or 5, characterized in that, In step (2), the metal in the metal target is Ti, W or Si, and the atomic content of the doped metal in the amorphous carbon lubricating film is <15%, and the internal stress of the film is <0.4GPa.

7. The preparation method according to claim 1, characterized in that, In step (2), the deposition thickness of the amorphous carbon lubricating film is 1~5 μm.

8. The preparation method according to claim 1, characterized in that, In step (3), the other two-dimensional lubricating materials are MoS2, WS2, TaSe2, NbSe2, graphene, or hexagonal boron nitride.

9. The preparation method according to claim 1 or 8, characterized in that, In step (3), the number of layers of the MXene material and other two-dimensional lubricating materials is less than 30; the concentration of the MXene-based heterogeneous compound dispersion is 2~14 g / L.

10. The preparation method according to claim 1, characterized in that, In step (3), the thickness of the MXene-based heterogeneous composite lubricating coating is 10~50 μm.

Images