A surface-textured low-friction diamond-like solid-liquid composite lubricating coating and a preparation method thereof

Abstract

This invention belongs to the field of material surface coating technology, and relates to a lubricating coating and its preparation method. It is particularly applicable to a surface-textured low-friction diamond-like carbon (DLC) solid-liquid composite lubricating coating and its preparation method used in mechanical moving parts. The coating is deposited on the friction surface of a substrate with relative frictional motion. It includes a diamond-like carbon (DLC) base coating as a solid phase and a lubricating oil layer as a liquid phase filling the spaces between the friction pairs. The DLC base coating is directly deposited on the friction surface of the substrate, and its surface is textured to form a regularly arranged micro-textured array. The lubricating oil layer is distributed at the friction interface where the micro-textured array is located and fills the interior of the micro-textured array. This application's solution constructs a surface array structure with micro-oil reservoirs and dynamic pressure bearing functions through the micro-textured design and control of the DLC solid phase surface, thereby achieving synergistic lubrication enhancement between the DLC coating and the lubricating oil at the physical mechanism level.

Description

Technical Field

[0001] This invention belongs to the field of material surface coating technology, and relates to a lubricating coating and its preparation method, especially applicable to a surface-textured low-friction diamond-like solid-liquid composite lubricating coating and its preparation method used in mechanical moving parts. Background Technology

[0002] With the rapid development of aerospace, deep-sea exploration, precision manufacturing, and high-end automotive industries, critical mechanical moving components (such as bearings, gears, and piston rings) face increasingly harsh operating environments, often requiring long-term reliable operation under extreme conditions such as high speed, heavy load, and frequent start-stop cycles. Under these conditions, traditional single-liquid lubrication often struggles to form a stable oil film, easily leading to severe friction, wear, and energy loss. While single solid self-lubricating coatings perform reasonably well under dry friction, they still have shortcomings in terms of bonding strength and long-term service life. Therefore, developing solid-liquid composite lubrication technology that can adapt to complex operating conditions has become a research hotspot in the field of tribology.

[0003] Diamond-like carbon (DLC) coatings are considered ideal solid phase materials in solid-liquid composite lubrication systems due to their high hardness, low coefficient of friction, excellent wear resistance, and chemical inertness. Existing research typically improves the compatibility of DLC coatings with lubricating oils through doping or surface chemical modification, aiming to reduce friction through interfacial energy modulation. However, due to the inherent fluidity and migration properties of liquid lubricants, they are prone to leakage from the friction contact area under high contact loads or centrifugal forces. Traditional DLC coatings, in pursuit of low friction, are often made extremely smooth, but this smooth surface lacks the physical binding capacity of the lubricating medium. Therefore, when operating conditions fluctuate (such as a sudden increase in load) or lubricating oil supply is limited, the hydrodynamic effect at the contact interface weakens rapidly, and the originally continuous lubricating oil film breaks down due to insufficient load-bearing capacity. This instability of the oil film inevitably leads to a shift in the lubrication state of the friction pair from fluid lubrication to mixed lubrication or even boundary lubrication.

[0004] Surface structure design and control of DLC coating materials, combined with synergistic lubrication technology using lubricants and additives, is an effective way to solve the aforementioned key technical and application bottlenecks, extend component lifespan, achieve reliable operation, and reduce energy consumption. However, the lubrication efficiency of solid-liquid composite systems is highly dependent on the microscopic geometry of the material surface. Different surface microstructures not only directly determine the stress distribution in the contact area but also profoundly affect the rheological behavior of the lubricating fluid at the friction interface and the storage and transport capacity of the lubricating oil.

[0005] It is evident that overcoming the limitations of traditional smooth surfaces and developing high-performance surface-textured solid-liquid composite lubricating materials and technologies is an important research topic in the field of tribology and a key direction for breaking through the bottlenecks of existing solid-liquid composite lubrication technologies. Summary of the Invention

[0006] This application provides a surface-textured low-friction diamond-like carbon (DLC) solid-liquid composite lubricating coating and its preparation method. By designing and controlling the microtexturation of the DLC solid phase surface, a surface array structure with micro oil reservoir and dynamic pressure bearing function is constructed, thereby achieving synergistic lubrication enhancement between the DLC coating and lubricating oil in terms of physical mechanism.

[0007] To achieve the above technical objectives, the technical solution adopted in this application is: a surface-textured low-friction diamond-like solid-liquid composite lubricating coating, which is disposed on the friction surface of a substrate with relative frictional motion; It includes a diamond-like carbon-based coating as a solid phase and a lubricating oil layer as a liquid phase filling the spaces between the friction pairs; The diamond-like carbon-based coating is directly deposited on the friction surface of the substrate, and its surface has been textured to form a regularly arranged array of microtextures. The lubricating oil layer is distributed at the friction interface formed by the relative motion of the friction pair and fills the interior of the microtexture array.

[0008] Furthermore, the material of the substrate is cemented carbide, steel, aluminum alloy, magnesium alloy, or titanium alloy.

[0009] Furthermore, the lubricating oil used in the lubricating oil layer includes polyolefins, synthetic esters, polyalkyl ethers, polysiloxanes, or perfluoropolyethers.

[0010] Furthermore, the thickness of the liquid phase of the lubricating oil layer is 0–150 nm.

[0011] Furthermore, the microtexture array is a microgroove array; its width is 20-60 nm, its depth is 10-20 nm, and its texture area occupies 5%-30%.

[0012] Furthermore, the diamond-like carbon-based coating is made of sp 2 and sp 3 Amorphous carbon materials composed of hybrid structures, sp 2 The carbon structure content is higher than 40 at.%, and the thickness of the diamond-like carbon-based coating is 1–2 µm.

[0013] The present invention also provides a method for preparing the above-mentioned surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating, the method comprising the following steps: a. Using an ion source with Ar gas as the working gas source, the substrate surface is etched to remove impurities from the substrate surface; b. A diamond-like carbon (DLC) coating is prepared on the substrate surface using magnetron sputtering deposition technology. The specific process is as follows: turn on the magnetron sputtering source, select a graphite target with a purity of not less than 99.9% (mass fraction) as the sputtering target, introduce argon gas, and deposit a diamond-like carbon solid phase. c. Perform laser surface texturing treatment on the prepared diamond-like carbon (DLC) coating surface. By controlling the processing parameters, a microtexture array with a preset morphology, size and arrangement is processed on the DLC coating surface. d. Liquid phase lubricating oil is introduced into the surface and interior of the microtexture array, and a solid-liquid composite lubricating coating is formed through the adsorption and storage of lubricating oil by the microtexture array.

[0014] Furthermore, in step a, the ion source used has an operating current of 0.3A, an operating power of 250-400W, and a negative bias voltage of 150V against the substrate.

[0015] Furthermore, in step b, the magnetron sputtering target power is 1.0–1.8 kW, the operating current is 2.0–3.5 A, and the negative bias voltage to the substrate is 60–120 V.

[0016] Furthermore, in the texturing process of step c, laser processing is used, with a laser wavelength of 1064nm or 532nm, a pulse width of nanosecond or picosecond, and a single pulse energy of 5 to 50µJ.

[0017] Beneficial effects The surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating utilizes the microgroove array as a micro-oil reservoir and hydrodynamic generating unit. Working in conjunction with the lubricating oil layer, it generates a hydrodynamic effect during friction and traps wear debris, thereby reducing the frictional resistance between the substrates. Specifically: First, because the coating includes a diamond-like carbon (DLC) solid phase and a lubricating oil liquid phase, the DLC solid phase has high hardness, excellent wear resistance, and chemical inertness, providing rigid support and anti-wear protection for the friction pair. Combined with the fluid lubrication behavior of the lubricating oil liquid phase, the synergistic effect of the two significantly reduces the direct contact and self-consumption of the solid phase. Second, the regularly distributed microgroove texture on the surface of the DLC-based coating can generate additional hydrodynamic pressure during friction, significantly improving the load-bearing capacity of the oil film, while storing lubricating oil and hard wear debris, ensuring continuous lubrication supply to the friction interface and preventing three-body wear. Third, the DLC-based coating is mainly composed of carbon elements, which has excellent chemical stability, thus avoiding the frictional wear induced by electrochemical corrosion of metal-based coatings in complex lubricating media.

[0018] The method for preparing the solid-liquid composite lubricating coating has the following advantages: First, a method combining magnetron sputtering deposition with laser surface texturing post-processing is employed. Magnetron sputtering enables large-area uniform deposition of high-quality diamond-like carbon (DLC)-based coatings; while the subsequent laser texturing process is a non-contact process, characterized by high processing precision, fast processing speed, and strong pattern design flexibility. Furthermore, the process is simple, clean, and easily automated for industrial production. Second, nanosecond or picosecond-level short-pulse lasers are preferably used for "cold processing" or "micro-thermal processing," confining the heat-affected zone to an extremely small area. This not only creates the desired microstructure on the coating surface but also avoids large-area graphitization transformation of the surrounding DLC ​​structure due to overheating, thus fully preserving the high intrinsic hardness and mechanical properties of the DLC solid phase. Attached Figure Description

[0019] Figure 1 This is a comparison chart of the friction coefficients of the solid-liquid composite lubricating coating samples prepared in Example 1 and the comparative example; Figure 2 This is a comparison chart of the friction coefficients of the solid-liquid composite lubricating coating samples prepared in Example 2 and the comparative example; Figure 3 This is a comparison chart of the friction coefficients of the solid-liquid composite lubricating coating samples prepared in Example 3 and the comparative example. Detailed Implementation

[0020] The embodiments of the present invention will be further described below with reference to the accompanying drawings: This invention provides a surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating and its preparation method.

[0021] A surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating comprises a diamond-like carbon base coating as a solid phase and an intermediate lubricating oil layer as a liquid phase.

[0022] In this system, the diamond-like carbon (DLC) coating serves as the solid phase on the mating surfaces of the friction pair, while the lubricating oil acts as the intermediate liquid phase. During friction, the DLC solid phase exhibits high hardness and excellent physicochemical properties such as wear resistance, lubrication, corrosion resistance, and load-bearing capacity. Combined with the fluid lubrication behavior of the lubricating oil, these properties synergistically improve the friction performance.

[0023] Specifically, the low-friction diamond-like carbon (DLC) solid-liquid composite lubricating coating is applied to two or more substrates in a frictional working condition. In detail, a DLC-based coating is applied to the friction surfaces of the substrates, with a lubricating oil layer serving as an intermediate liquid phase between the DLC-based coatings of the substrates in the frictional working condition. The surface of the DLC-based coating undergoes laser texturing treatment to form a micro-textured array; specifically, the micro-textured array is a regularly arranged array of microgrooves. The width of the microgrooves array is 20–60 nm, the depth is 10–20 nm, and the area occupancy is 5%–30%. Utilizing the microgrooves array on the solid phase surface of the DLC-based coating as a micro-oil reservoir, lubricating oil is continuously supplied to the friction interface under lean oil or start-stop conditions. Furthermore, the micro-textured units generate a hydrodynamic pressure effect during relative motion, significantly improving the oil film's load-bearing capacity. In addition, the micro-textured array's ability to capture and contain wear debris reduces three-body wear, achieving optimal friction-reducing and lubrication performance. Similarly, it improves the friction reduction and lubrication performance between two or more substrates with diamond-like carbon coatings on their surfaces, while also preventing direct contact between smooth diamond-like carbon coating surfaces due to oil film rupture under heavy loads, thus avoiding increased frictional resistance between the substrates.

[0024] The coefficient of friction of the composite lubricating coating is between 0 and 0.06.

[0025] The material of the composite lubricating coating substrate is cemented carbide, various types of steel, aluminum alloy, magnesium alloy, titanium alloy, etc.

[0026] The liquid phase of the composite lubricating coating is polyolefin, synthetic ester, polyalkyl ether, polysiloxane, perfluoropolyether, etc. For example, the polyolefin is Chevron Phillips' Synfluid® PAO series; the synthetic ester is Nyco's NYCOBASE series.

[0027] The thickness of the liquid phase of the composite lubricating coating is 0–150 nm.

[0028] The diamond-like carbon-based solid phase (diamond-like carbon-based coating) of the composite lubricating coating is a large class of sp 2 sp 3 A general term for amorphous carbon materials with hybrid structures, and the surface of the solid phase is shaped by laser processing of microgrooves.

[0029] The diamond-like solid phase of the composite lubricating coating (sp) 2 The carbon structure content is higher than 40 at.%, and the thickness is 1 to 2 µm.

[0030] Compared with existing technologies, the solid-liquid composite lubricating coating has the following advantages: First, because the coating includes a diamond-like carbon (DLC) solid phase and a lubricating oil liquid phase, the DLC solid phase has high hardness, excellent wear resistance, and chemical inertness, providing rigid support and anti-wear protection for the friction pair. Combined with the fluid lubrication behavior of the lubricating oil liquid phase, the synergistic effect of the two significantly reduces the direct contact and self-consumption of the solid phase. Second, the regularly distributed microgroove texture on the surface of the DLC-based coating can generate additional hydrodynamic pressure during friction, significantly improving the load-bearing capacity of the oil film, while storing lubricating oil and hard wear debris, ensuring continuous lubrication supply to the friction interface and preventing three-body wear. Third, the DLC-based coating is mainly composed of carbon elements, which has excellent chemical stability, thus avoiding the frictional wear induced by electrochemical corrosion of metal-based coatings in complex lubricating media.

[0031] This invention also provides a method for preparing a solid-liquid composite lubricating coating, wherein the method for preparing the diamond-like solid phase of the coating includes the following steps: (1) Provide a substrate, use an ion source and Ar gas as the working gas source to etch the surface of the substrate to be prepared with the composite lubricating coating in order to remove impurities on the substrate surface; (2) A diamond-like carbon (DLC) coating was prepared on the substrate surface after step (1) by magnetron sputtering deposition. The specific process is as follows: turn on the magnetron sputtering source, select high-purity graphite as the sputtering target, introduce argon gas, and deposit a diamond-like carbon solid phase. (3) Laser surface texturing treatment is performed on the prepared diamond-like carbon-based coating surface. By controlling the processing parameters, a micro-texture array with a preset size and distribution is constructed on the coating surface.

[0032] The ion source used in step (1) has a working current of 0.3A, a working power of 250-400W, and a negative bias voltage of 150V for the substrate.

[0033] In step (2), the magnetron sputtering target power is 1.0 to 1.8 kW, the operating current is 2.0 to 3.5 A, and the negative bias voltage to the substrate is 60 to 120 V.

[0034] In the texturing process of step (3), laser processing is used, with a laser wavelength of 1064nm or 532nm, a pulse width of nanosecond or picosecond, and a single pulse energy of 5 to 50µJ.

[0035] The following describes the surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating and its preparation method according to specific embodiments of the present invention: Example 1:

[0036] A method for preparing a surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating includes the following steps: (1) Place the ultrasonically cleaned and dried substrate on the workpiece holder in the vacuum deposition chamber; (2) Start the vacuum system and wait for the pressure in the vacuum chamber to reach 2.7 × 10⁻ 3 At Pa, turn on the linear ion source; introduce argon (Ar) gas at a flow rate of 40 sccm into the linear ion source, set the operating current of the linear ion source to 0.2A and the operating power to 280W, and simultaneously apply a substrate negative bias voltage of 100V to etch and clean the substrate surface for 15 minutes to remove the surface oxide layer and impurities. (3) Depositing diamond-like solid phase on the substrate surface: Turn on the magnetron sputtering source and select high-purity graphite with a purity of ≥99.99% as the sputtering target; introduce argon gas with a flow rate of 50 sccm into the magnetron sputtering source, adjust the magnetron sputtering target power to 1350W, the working current to 2.8A, and simultaneously apply a substrate negative bias voltage of 50V to control the deposition working gas pressure to be maintained at 0.46Pa, and the deposition time to 1 hour.

[0037] (4) After deposition, wait for the vacuum chamber temperature to cool naturally to room temperature, open the chamber and take out the substrate to obtain a sample with a diamond-like base coating deposited on the surface.

[0038] (5) The sample with the deposited diamond-like carbon (DLC) coating was placed on a precision laser processing platform, and a picosecond laser (wavelength 532 nm, pulse width 10 ps) was used for surface microtexturing. The laser single pulse energy was set to 5–20 µJ, and the repetition frequency was 100 kHz. By precisely controlling the laser spot path and the number of pulse etchings, microgrooves arranged in an array were prepared on the surface of the DLC coating. In this embodiment, three sets of samples were prepared, with the width of the microgrooves all being 20 nm and the area occupancy rate being 10%. By adjusting the laser power and etching time, the depth of the microgrooves in the three sets of samples was controlled to be 10 nm, 15 nm, and 20 nm, respectively. After laser processing, the samples were ultrasonically cleaned in anhydrous ethanol for 20 min to remove the recast layer and debris generated by laser ablation on the surface, and then dried for later use.

[0039] (6) The diamond-like base coatings prepared above are used as the upper and lower solid phases of the composite coating, respectively. Polyolefin is selected as the lubricating oil and added to the friction interface of the upper and lower solid phases to form a solid-liquid composite lubricating coating.

[0040] (7) The solid-liquid composite lubricating coating prepared above was characterized and tested. The film thickness of both the upper and lower diamond-like solid phases was measured to be 1.2 µm; the microgroove width was 20 nm, and the depths were 10 nm, 15 nm, and 20 nm, respectively; the effective thickness of the polyolefin lubricating oil film was approximately 100 nm. Friction tests were conducted under a contact pressure of 5 GPa, and the coefficients of friction of the coating at this pressure were 0.012, 0.005, and 0.028, respectively. Figure 1 As shown.

[0041] Example 2: A method for preparing a surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating includes the following steps: (1) Place the ultrasonically cleaned and dried substrate on the workpiece holder in the vacuum deposition chamber; (2) Start the vacuum system and wait for the pressure in the vacuum chamber to reach 2.7 × 10⁻ 3 At Pa, turn on the linear ion source; introduce argon (Ar) gas at a flow rate of 40 sccm into the linear ion source, set the operating current of the linear ion source to 0.2A and the operating power to 280W, and simultaneously apply a substrate negative bias voltage of 100V to etch and clean the substrate surface for 15 minutes to remove the surface oxide layer and impurities. (3) Depositing diamond-like solid phase on the substrate surface: Turn on the magnetron sputtering source and select high-purity graphite with a purity of ≥99.99% as the sputtering target; introduce argon gas with a flow rate of 50 sccm into the magnetron sputtering source, adjust the magnetron sputtering target power to 1350W, the working current to 2.8A, and simultaneously apply a substrate negative bias voltage of 50V to control the deposition working gas pressure to be maintained at 0.46Pa, and the deposition time to 1 hour.

[0042] (4) After deposition, wait for the vacuum chamber temperature to cool naturally to room temperature, open the chamber and take out the substrate to obtain a sample with a diamond-like base coating deposited on the surface.

[0043] (5) The sample with the deposited diamond-like carbon (DLC) coating was placed on a precision laser processing platform, and a picosecond laser (wavelength 532 nm, pulse width 10 ps) was used for surface microtexturing. The laser single pulse energy was set to 5–20 µJ, and the repetition frequency was 100 kHz. By precisely controlling the laser spot path and the number of pulse etchings, microgrooves arranged in an array were prepared on the surface of the DLC coating. In this embodiment, three sets of samples were prepared, with the width of the microgrooves kept at 40 nm and the area occupancy rate at 20%. By adjusting the laser power and etching time, the depth of the microgrooves in the three sets of samples was controlled to be 10 nm, 15 nm, and 20 nm, respectively. After laser processing, the samples were ultrasonically cleaned in anhydrous ethanol for 20 min to remove the recast layer and debris generated by laser ablation on the surface, and then dried for later use.

[0044] (6) The diamond-like base coatings prepared above are used as the upper and lower solid phases of the composite coating, respectively. Polyolefin is selected as the lubricating oil and added to the friction interface of the upper and lower solid phases to form a solid-liquid composite lubricating coating.

[0045] (7) The solid-liquid composite lubricating coating prepared above was characterized and tested. The film thickness of both the upper and lower diamond-like solid phases was measured to be 1.4 µm; the microgroove width was 40 nm, and the depths were 10 nm, 15 nm, and 20 nm, respectively; the effective thickness of the polyolefin lubricating oil film was approximately 100 nm. Friction tests were conducted under a contact pressure of 5 GPa, and the coefficients of friction of the coating at this pressure were 0.025, 0.020, and 0.025, respectively. Figure 2 As shown.

[0046] Example 3: A method for preparing a surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating includes the following steps: (1) Place the ultrasonically cleaned and dried substrate on the workpiece holder in the vacuum deposition chamber; (2) Start the vacuum system and wait for the pressure in the vacuum chamber to reach 2.7 × 10⁻ 3 At Pa, turn on the linear ion source; introduce argon (Ar) gas at a flow rate of 40 sccm into the linear ion source, set the linear ion source operating current to 0.2A, operating power to 280W, apply a substrate negative bias voltage of 100V, and etch and clean the substrate surface for 15 minutes to remove the surface oxide layer and impurities. (3) Depositing diamond-like solid phase on the substrate surface: Turn on the magnetron sputtering source and select high-purity graphite with a purity of ≥99.99% as the sputtering target; introduce argon gas with a flow rate of 50 sccm into the magnetron sputtering source, adjust the magnetron sputtering target power to 1350W, the working current to 2.8A, and simultaneously apply a substrate negative bias voltage of 50V to control the deposition working gas pressure to be maintained at 0.46Pa, and the deposition time to 1 hour.

[0047] (4) After deposition, wait for the vacuum chamber temperature to cool naturally to room temperature, open the chamber and take out the substrate to obtain a sample with a diamond-like base coating deposited on the surface.

[0048] (5) The sample with the deposited diamond-like carbon (DLC) coating was placed on a precision laser processing platform, and a picosecond laser (wavelength 532 nm, pulse width 10 ps) was used for surface microtexturing. The laser single pulse energy was set to 5–20 µJ, and the repetition frequency was 100 kHz. By precisely controlling the laser spot path and the number of pulse etchings, microgrooves arranged in an array were prepared on the surface of the DLC coating. In this embodiment, three sets of samples were prepared, with the width of the microgrooves all being 60 nm and the area occupancy rate being 30%. By adjusting the laser power and etching time, the depth of the microgrooves in the three sets of samples was controlled to be 10 nm, 15 nm, and 20 nm, respectively. After laser processing, the samples were ultrasonically cleaned in anhydrous ethanol for 20 min to remove the recast layer and debris generated by laser ablation on the surface, and then dried for later use.

[0049] (6) The diamond-like base coatings prepared above are used as the upper and lower solid phases of the composite coating, respectively. Polyolefin is selected as the lubricating oil and added to the friction interface of the upper and lower solid phases to form a solid-liquid composite lubricating coating.

[0050] (7) The solid-liquid composite lubricating coating prepared above was characterized and tested. The film thickness of both the upper and lower diamond-like solid phases was measured to be 1.4 µm; the microgroove width was 60 nm, and the depths were 10 nm, 15 nm, and 20 nm, respectively; the effective thickness of the polyolefin lubricating oil film was approximately 100 nm. Friction tests were conducted under a contact pressure of 5 GPa, and the coefficients of friction of the coating at this pressure were 0.053, 0.032, and 0.049, respectively. Figure 3 As shown.

[0051] Comparative Example: This embodiment is a comparative embodiment of the above embodiments 1, 2, and 3.

[0052] In this embodiment, the preparation method of the solid-liquid composite lubricating coating is basically the same as that in Example 1. The difference is that in step (5), after preparing the diamond-like solid phase, no laser surface texturing treatment is performed. The other process steps are the same as those in Example 1.

[0053] Analysis of the prepared solid-liquid composite lubricating coating revealed that the thickness of the upper and lower amorphous carbon solid phases was 1.4 µm, the microgroove width was 0 nm, and the depth was 0 nm, while the thickness of the polyolefin lubricating oil was approximately 100 nm. Friction testing showed that the coating's coefficient of friction at a contact pressure of 5 GPa was 0.102. Figure 1 , 2 As shown in Figure 3.

Claims

1. A surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating, characterized in that: It is disposed on the friction surface of a substrate in which there is relative frictional motion; It includes a diamond-like carbon-based coating as a solid phase and a lubricating oil layer as a liquid phase filling the spaces between the friction pairs; The diamond-like carbon-based coating is directly deposited on the friction surface of the substrate, and its surface is textured to form a regularly arranged microtexture array. The lubricating oil layer is distributed at the friction interface formed by the relative motion of the friction pair and fills the interior of the microtexture array.

2. The surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 1, characterized in that: The substrate is made of cemented carbide, steel, aluminum alloy, magnesium alloy, or titanium alloy.

3. The surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 1, characterized in that: The lubricating oil used in the lubricating oil layer includes polyolefins, synthetic esters, polyalkyl ethers, polysiloxanes, or perfluoropolyethers.

4. The surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 1, characterized in that: The thickness of the liquid phase of the lubricating oil layer is 0–150 nm.

5. The surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 1, characterized in that: The microtexture array is a microgroove array; Its width is 20-60nm, its depth is 10-20nm, and its texture area occupies 5%-30%.

6. The surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 1, characterized in that: The diamond-like carbon-based coating is made of sp 2 and sp 3 Amorphous carbon materials composed of hybrid structures, sp 2 The carbon structure content is higher than 40 at.%, and the thickness of the diamond-like carbon-based coating is 1–2 µm.

7. A method for preparing a surface-textured, low-friction diamond-like carbon solid-liquid composite lubricating coating as described in claim 1, characterized in that: Includes the following steps a. Using an ion source with Ar gas as the working gas source, the substrate surface is etched to remove impurities from the substrate surface; b. A diamond-like carbon (DLC) coating is prepared on the substrate surface using magnetron sputtering deposition technology. The specific process is as follows: turn on the magnetron sputtering source, select a graphite target with a purity of not less than 99.9% (mass fraction) as the sputtering target, introduce argon gas, and deposit a diamond-like carbon solid phase. c. Perform laser surface texturing treatment on the prepared diamond-like carbon (DLC) coating surface. By controlling the processing parameters, a microtexture array with a preset morphology, size and arrangement is processed on the DLC coating surface. d. Liquid phase lubricating oil is introduced into the surface and interior of the microtexture array, and a solid-liquid composite lubricating coating is formed through the adsorption and storage of lubricating oil by the microtexture array.

8. The method for preparing a surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 7, characterized in that: In step a, the ion source used has an operating current of 0.3A, an operating power of 250-400W, and a negative bias voltage of 150V against the substrate.

9. The method for preparing a surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 7, characterized in that: In step b, the magnetron sputtering target power is 1.0 to 1.8 kW, the operating current is 2.0 to 3.5 A, and the negative bias voltage to the substrate is 60 to 120 V.

10. The method for preparing a surface-textured low-friction diamond-like carbon solid-liquid composite lubricating coating according to claim 7, characterized in that: In the texturing process of step c, laser processing is used, with a laser wavelength of 1064nm or 532nm, a pulse width of nanosecond or picosecond, and a single pulse energy of 5 to 50µJ.

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