Fluorine-containing lubricating oil for fluorine-doped diamond-like film and lubricating method of fluorine-doped diamond-like film

Abstract

The invention provides fluorine-containing lubricating oil for a fluorine-doped diamond-like film and a lubricating method of the fluorine-doped diamond-like film. The fluorine-containing lubricating oil comprises basic lubricating oil and a lubricating additive, wherein the molecules of the lubricating additive comprise hydroxyl and fluorine element; wherein based on the mass of the fluorine-containing lubricating oil, the ratio of the lubricating additive is 1 wt.%-20 wt.%. The diamond-like carbon film is doped with fluorine, so that the surface structure of the diamond-like carbon film can be changed, and the surface adsorbability of fluorine-containing lubricating oil on the diamond-like carbon film is enhanced. When the fluorine-containing lubricating oil is used for lubricating a fluorine-doped diamond film, a friction reaction film is formed, an extremely low friction coefficient is achieved, the lubricating efficiency is remarkably improved, and the service life is remarkably prolonged. The fluorine-containing lubricating oil for the fluorine-doped diamond film can provide excellent lubricating effect and wear resistance in various applications, meets the requirements of modern industry, and has the potential of large-scale production and application.

Description

Technical Field

[0001] The invention relates to a fluorine-containing lubricating oil for a fluorine-doped diamond-like film and a lubricating method for the fluorine-doped diamond-like film, belonging to the technical field of lubricating oil. Background Art

[0002] In moving mechanical systems, friction and wear are ubiquitous phenomena, which lead to increasingly prominent problems such as energy consumption and mechanical loss. Research on lubrication and friction reduction technology is of great significance for improving the friction state of mechanical systems, reducing friction and controlling wear, improving resource utilization and reducing material consumption. The most effective way to control or reduce friction and wear is to use lubricating oil.

[0003] Currently, ultra-low friction can be achieved on diamond-like carbon films (DLC) under vacuum or nitrogen conditions, but it cannot effectively reduce friction under atmospheric conditions. To solve this problem, oil-based lubricants are usually used to create a thin liquid film to isolate friction components (such as DLC), which can reduce the friction coefficient, improve lubricity, and reduce friction and wear of mobile mechanical systems under atmospheric conditions. For example, when DLC is lubricated with traditional oil-based lubricants such as perfluoropolyether, the friction coefficient is reduced compared to dry friction conditions, but the absolute value of the friction coefficient is still high, making it difficult to achieve efficient lubrication, and the lubricants that can be effectively dispersed in perfluoropolyether are very limited, and the friction coefficient and wear rate cannot be effectively reduced.

[0004] Therefore, developing new oil-based lubricants or improving existing oil-based lubricant systems to enhance the adsorption of the surface of friction parts, effectively reduce the friction coefficient, improve lubricity, and enable large-scale production and application of lubricants has become an urgent problem to be solved. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a fluorine-containing lubricating oil for fluorine-doped diamond-like film and a lubricating method for fluorine-doped diamond-like film. The fluorine-containing lubricating oil is used to lubricate the fluorine-doped diamond-like film, and a friction chemical reaction occurs to form a friction reaction film, which can enhance the adsorption of the fluorine-containing lubricating oil on the surface of the fluorine-doped diamond-like film and effectively reduce the friction coefficient.

[0006] To achieve the above object, in a first aspect, the present invention provides a fluorine-containing lubricating oil for fluorine-doped diamond-like carbon film, wherein the fluorine-containing lubricating oil comprises a base lubricating oil and a lubricating additive, and the molecules of the lubricating additive contain hydroxyl and fluorine elements. Preferably, based on the mass of the fluorine-containing lubricating oil, the lubricating additive accounts for 1wt.%-20wt.%; more preferably, the lubricating additive accounts for 5wt.%-10wt.%.

[0007] The fluorine-containing lubricating oil for fluorine-doped diamond-like film provided by the present invention has good fluidity and adhesion, and is not only convenient to apply on the doped diamond-like film and can evenly cover the friction surface, but also has good film-forming effect when used in combination with the doped diamond-like film, and can improve the adsorption of the fluorine-containing lubricating oil on its surface, reduce wear and friction, and reduce the friction coefficient, thereby improving the lubrication efficiency and service life of the fluorine-doped diamond-like film.

[0008] According to a specific embodiment of the present invention, preferably, the lubricating additive is selected from one or a combination of two or more of perfluorobutanol, perfluoropentanol, 1H,1H,2H,2H-perfluorohexan-1-ol, and octafluoroheptanol. Perfluoro compounds contain hydroxyl groups and fluorine elements, usually have a lower surface tension, can form a uniform chemical adsorption film with fluorine-doped diamond-like carbon film, and better penetrate into the friction surface. In addition, the presence of fluorine elements makes the fluorine-containing lubricant have a lower friction coefficient, thereby reducing wear and improving mechanical efficiency.

[0009] According to a specific embodiment of the present invention, preferably, the base lubricant is perfluoropolyether; more preferably, the specification of the perfluoropolyether in the present invention is: Mw is 1500 (CAS No.: 60164-51-4).

[0010] According to a specific embodiment of the present invention, preferably, the lubricating additive is a lubricating additive soluble in perfluoropolyether. The lubricating additive is compatible with the base lubricating oil, can avoid stratification or precipitation, and ensure uniform distribution.

[0011] In a second aspect, the present invention further provides a method for lubricating a fluorine-doped diamond-like carbon film, comprising the following steps:

[0012] The fluorine-doped diamond-like carbon film is lubricated using the fluorine-containing lubricating oil.

[0013] According to a specific embodiment of the present invention, preferably, the amount of the fluorine-containing lubricant is: per 1cm 2 The fluorine-doped diamond-like carbon film uses 5-30 μL of fluorine-containing lubricant; more preferably, every 1 cm 2 The fluorine-doped diamond-like film uses 20 μL of fluorine-containing lubricating oil. The fluorine-containing lubricating oil of the present invention only needs to be simply applied on the fluorine-doped diamond-like film to form an effective lubricating film, without the need for complex sealing measures, thus simplifying the operation process and improving the convenience of use.

[0014] According to a specific embodiment of the present invention, preferably, the content of fluorine in the fluorine-doped diamond-like carbon film is 5%-20%, preferably 10%-15%.

[0015] According to a specific embodiment of the present invention, preferably, the thickness of the fluorine-doped diamond-like film is 800-1000 nm. Within this thickness range, the hardness, low friction and chemical stability of the fluorine-doped diamond-like film can be fully exerted.

[0016] According to a specific embodiment of the present invention, preferably, the Young's modulus of the fluorine-doped diamond-like film is 10-50 GPa, and the hardness is 1-7 GPa; more preferably, the Young's modulus of the fluorine-doped diamond-like film is 35 GPa, and the hardness is 3.5 GPa.

[0017] According to a specific embodiment of the present invention, preferably, the fluorine-doped diamond-like film is prepared by deposition on the surface of a substrate material, and more preferably, the fluorine-doped diamond-like film is prepared by deposition on the surface of a substrate material by chemical vapor deposition; the deposition time is preferably controlled to be 0.5-2h. Wherein, the substrate material is preferably selected from one or a combination of two or more of silicon wafer, carbon steel, and alloy steel.

[0018] According to a specific embodiment of the present invention, preferably, the lubrication method also includes a process of ultrasonically dispersing polytetrafluoroethylene (PTFE) nanoparticles in the fluorine-containing lubricating oil. Specifically, the lubricating additive and perfluoropolyether are first mixed evenly to prepare the fluorine-containing lubricating oil, and then PTFE nanoparticles with a particle size of 2-3 μm are selected, and the PTFE nanoparticles are completely dispersed in the fluorine-containing lubricating oil by ultrasonication for 0.25-2 hours; wherein the mass ratio of the fluorine-containing lubricating oil to the PTFE nanoparticles is (10-30):1. More preferably, the mass ratio of the fluorine-containing lubricating oil to the polytetrafluoroethylene nanoparticles is 20:1; the time of the ultrasonic dispersion can be controlled to be 1 hour.

[0019] The present invention modifies PTFE nanoparticles by ultrasonic dispersion in fluorine-containing lubricating oil, and can achieve uniform distribution of PTFE in fluorine-containing lubricating oil to form a composite fluorine-containing lubricating oil. The fluorine-containing lubricating oil containing PTFE is applied to the surface of fluorine-doped diamond-like film to form an efficient lubricating layer. The low friction characteristics of PTFE can effectively reduce the friction coefficient, improve the lubrication effect, and enhance the performance of the lubricating oil. In addition, the lubricated fluorine-doped diamond-like film and the polytetrafluoroethylene ball with a diameter of 10 mm together form a friction pair, and the friction between the two forms a friction system. Through the synergistic effect of the two, the overall friction performance and durability can be improved, thereby further reducing friction and wear.

[0020] The diamond-like film is doped with fluorine elements, which can change the surface structure of the diamond-like film and enhance the adsorption of fluorine-containing lubricating oil on its surface. The fluorine-containing lubricating oil provided by the present invention comprises a base lubricating oil and a lubricating additive, and the molecules of the lubricating additive contain hydroxyl groups and fluorine elements. When the fluorine-containing lubricating oil provided by the present invention is used to lubricate the fluorine-doped diamond-like film, a chemical reaction will occur during the friction process to form a friction reaction film, effectively reducing the friction coefficient and significantly improving the lubrication efficiency and service life of the fluorine-doped diamond-like film.

[0021] The fluorine-containing lubricating oil for fluorine-doped diamond-like carbon film provided by the present invention is a high-performance lubricating material, which can provide excellent lubrication effect and wear resistance in various applications, meet the needs of modern industry, and has the potential for large-scale production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a curve diagram showing the change of the friction coefficient of the friction pairs obtained in Example 1 and Example 6 and the friction pair obtained in Comparative Example 1 over time;

[0023] Figure 2 is a curve diagram showing the change of the friction coefficient of the friction pair obtained in Example 2 and the friction pair obtained in Comparative Examples 2-4 over time;

[0024] Figure 3 is a curve diagram showing the change of the friction coefficient of the friction pair obtained in Example 1 and the friction pair obtained in Comparative Example 2 over time;

[0025] Figure 4 is a graph showing the change in friction coefficient of the friction pairs obtained in Examples 3-5 and the friction pair obtained in Comparative Example 5 over time;

[0026] Figure 5 It is a curve diagram showing the change of the friction coefficient of the friction pair obtained in Example 1 and the friction pair obtained in Comparative Example 6 over time. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0028] Example 1

[0029] This embodiment provides a lubrication method for a fluorine-doped diamond-like carbon film, comprising the following steps:

[0030] Step 1: Depositing a fluorine-doped diamond film with a thickness of about 1000 nm on a silicon wafer by chemical vapor deposition;

[0031] Step 2: mixing perfluorobutanol and perfluoropolyether (CAS No.: 60164-51-4) to obtain a fluorinated lubricating oil, wherein the perfluorobutanol in the fluorinated lubricating oil accounts for 20 wt.%;

[0032] The fluorine-doped diamond film is lubricated with fluorine-containing lubricating oil. 2 The fluorine-doped diamond-like film was lubricated with 20 μL of fluorine-containing lubricating oil, and the lubricated fluorine-doped diamond-like film and a polytetrafluoroethylene ball with a diameter of 10 mm formed a friction pair.

[0033] Example 2

[0034] This embodiment provides a lubrication method for a fluorine-doped diamond-like carbon film, comprising the following steps:

[0035] Step 1: Depositing a fluorine-doped diamond film with a thickness of about 1000 nm on a silicon wafer by chemical vapor deposition;

[0036] Step 2: mixing perfluorobutanol and perfluoropolyether (CAS No.: 60164-51-4) to obtain a fluorinated lubricating oil, wherein the perfluorobutanol in the fluorinated lubricating oil accounts for 5 wt.%;

[0037] The fluorine-doped diamond film is lubricated with fluorine-containing lubricating oil. 2 The fluorine-doped diamond-like film was lubricated with 20 μL of fluorine-containing lubricating oil, and the lubricated fluorine-doped diamond-like film and a polytetrafluoroethylene ball with a diameter of 10 mm formed a friction pair.

[0038] Example 3

[0039] This embodiment provides a lubrication method for a fluorine-doped diamond-like carbon film, which differs from Embodiment 2 only in that: in step 2, 5 wt.% perfluoropentanol and perfluoropolyether (CAS No.: 60164-51-4) are mixed to obtain a fluorine-containing lubricating oil.

[0040] Example 4

[0041] This embodiment provides a lubrication method for a fluorine-doped diamond-like carbon film, which differs from Embodiment 2 only in that: in step 2, 5 wt.% 1H,1H,2H,2H-perfluorohexan-1-ol and perfluoropolyether (CAS No.: 60164-51-4) are mixed to obtain a fluorine-containing lubricating oil.

[0042] Example 5

[0043] This embodiment provides a lubrication method for a fluorine-doped diamond-like carbon film, which differs from Embodiment 2 only in that: in step 2, 5 wt.% octafluoroheptanol and perfluoropolyether (CAS No.: 60164-51-4) are mixed to obtain a fluorine-containing lubricating oil.

[0044] Example 6

[0045] This embodiment provides a lubrication method for a fluorine-doped diamond-like carbon film, comprising the following steps:

[0046] Step 1: Depositing a fluorine-doped diamond film with a thickness of about 1000 nm on a silicon wafer by chemical vapor deposition;

[0047] Step 2: mixing perfluorobutanol and perfluoropolyether (CAS No.: 60164-51-4) to obtain a fluorinated lubricating oil, wherein the perfluorobutanol in the fluorinated lubricating oil accounts for 20 wt.%;

[0048] Select PTFE nanoparticles with a particle size of 2-3 μm, add 50 mg of PTFE nanoparticles to 1 g of fluorinated lubricant, and perform ultrasonic treatment for 1 hour to completely disperse the nanoparticles in the fluorinated lubricant;

[0049] The fluorine-doped diamond film is lubricated with fluorine-containing lubricating oil containing PTFE nanoparticles. 2 The fluorine-doped diamond-like film was lubricated with 20 μL of fluorine-containing lubricating oil, and the lubricated fluorine-doped diamond-like film and a polytetrafluoroethylene ball with a diameter of 10 mm formed a friction pair.

[0050] Comparative Example 1

[0051] This comparative example provides a lubrication method for a fluorine-doped diamond-like carbon film, which differs from Example 1 only in that the fluorine-containing lubricating oil in step 2 is not used for lubrication treatment (dry friction).

[0052] Comparative Example 2

[0053] This comparative example provides a method for lubricating a fluorine-doped diamond-like carbon film, which differs from Example 2 only in that, in step 2, only perfluoropolyether is used to lubricate the fluorine-doped diamond-like carbon film.

[0054] Comparative Example 3

[0055] This comparative example provides a method for lubricating a fluorine-doped diamond-like carbon film, which differs from Example 2 only in that, in step 2, only perfluorobutanol is used to lubricate the fluorine-doped diamond-like carbon film.

[0056] Comparative Example 4

[0057] This comparative example provides a diamond-like carbon film lubrication method, which differs from Example 2 only in that: in step 1, a diamond-like carbon film (DLC) with a thickness of about 1000 nm is deposited on a silicon wafer by chemical vapor deposition.

[0058] Comparative Example 5

[0059] This comparative example provides a method for lubricating a fluorine-doped diamond-like carbon film, which differs from Example 1 only in that, in step 2, a liquid lubricant containing hydroxyl and carboxyl groups is used to lubricate the fluorine-doped diamond-like carbon film.

[0060] Comparative Example 6

[0061] This comparative example provides a lubrication method for a fluorine-doped diamond-like carbon film, which differs from Example 1 only in that: in step 2, the proportion of perfluorobutanol in the fluorine-containing lubricating oil is 50 wt.%.

[0062] Experimental example

[0063] The above-mentioned embodiments and comparative examples were subjected to tribological tests. The test conditions are as follows: the tribological tests were carried out at room temperature. In the embodiments of the present invention and comparative examples, polytetrafluoroethylene balls and fluorine-doped diamond films (F-DLC) were used as friction pairs. The polytetrafluoroethylene balls were used as the upper friction pair and were installed on the ball holder. The F-DLC was a sheet friction pair and was installed on the lower sample table. A polytetrafluoroethylene ball with a diameter of 10 mm was used, the rotation speed was 300 rpm, and the rotation radius was 2 mm. At the beginning of the experiment, the upper sample (polytetrafluoroethylene ball) was pressed downward, and a normal load of 2 N was applied. When the normal load reached the required size, the upper sample was no longer pressed downward. The lower sample table began to rotate, driving the F-DLC to rotate together, thereby realizing the friction test of the upper and lower samples. The results are shown as follows: Figure 1-5 As shown in Table 1; Figure 2 In the figure, F-DLC-5wt% perfluorobutanol represents the friction coefficient curve of the friction pair obtained in Example 2, F-DLC-perfluoropolyether represents the friction coefficient curve of the friction pair obtained in Comparative Example 2, F-DLC-perfluorobutanol represents the friction coefficient curve of the friction pair obtained in Comparative Example 3, and DLC-5wt% perfluorobutanol represents the friction coefficient curve of the friction pair obtained in Comparative Example 4.

[0064] Table 1

[0065] Experimental example lubricating oil Friction parts Friction coefficient Example 1 20wt.%Perfluorobutanol, perfluoropolyether F-DLC 0.004 Example 2 5wt.%Perfluorobutanol, perfluoropolyether F-DLC 0.01 Example 3 5wt.%Perfluoropentanol, perfluoropolyether F-DLC 0.008 Example 4 5wt.%1H,1H,2H,2H-perfluorohexan-1-ol, perfluoropolyether F-DLC 0.006 Example 5 5wt.% octafluoroheptanol, perfluoropolyether F-DLC 0.004 Example 6 20wt.%perfluorobutanol, perfluoropolyether, PTFE nanoparticles F-DLC 0.001 Comparative Example 1 / F-DLC 0.14 Comparative Example 2 Perfluoropolyether F-DLC 0.02 Comparative Example 3 Perfluorobutanol F-DLC 0.2 Comparative Example 4 5wt.%Perfluorobutanol, perfluoropolyether DLC 0.025 Comparative Example 5 Liquid lubricant containing hydroxyl and carboxyl groups F-DLC 0.1 Comparative Example 6 50wt.%perfluorobutanol, perfluoropolyether F-DLC 0.06

[0066] according to Figure 1 , Figure 3From the analysis of Table 1, it can be seen that Example 1 uses a fluorine-containing lubricating oil containing 20wt.% of perfluorobutanol and perfluoropolyether to lubricate the fluorine-doped diamond film (F-DLC), and the friction coefficient obtained by the test is 0.004. In contrast, in Comparative Example 1, no lubricating oil was used for dry friction, and the tested friction coefficient was 0.14. It can be seen that the use of the fluorine-containing lubricating oil in Example 1 significantly reduced the friction coefficient by more than 90%. This result shows that when the fluorine-containing lubricating oil lubricates the fluorine-doped diamond film, a chemical reaction occurs in the friction process to form a friction reaction film. Due to the lubricating properties of the fluorine-containing lubricating oil, the friction and wear between the contact surfaces can be reduced, thereby effectively reducing friction, improving lubrication performance, and significantly improving the lubrication efficiency and service life of the fluorine-doped diamond film. Figure 1 In Example 6, a fluorinated lubricant containing 20 wt.% of perfluorobutanol and perfluoropolyether is used, and PTFE nanoparticles are added and ultrasonically dispersed in the fluorinated lubricant for modification, so that PTFE is evenly distributed in the fluorinated lubricant to form a composite fluorinated lubricant, and the friction coefficient obtained by testing is 0.001. This shows that the fluorinated lubricant containing PTFE nanoparticles can be applied to the surface of the fluorine-doped diamond-like film to form an efficient lubricating layer, improve the performance of the lubricant, and make the friction coefficient lower.

[0067] according to Figure 4 From the analysis of Table 1, it can be seen that in Examples 3 to 5, fluorine-containing lubricating oils in combination with different amounts of lubricating additives and perfluoropolyether are used to lubricate the fluorine-doped diamond-like film, and the friction coefficient is reduced to below 0.01, which further indicates that when the fluorine-containing lubricating oil of the present invention is used to lubricate the fluorine-doped diamond-like film, a friction reaction film is formed, which significantly reduces friction and improves lubrication performance.

[0068] according to Figure 2 From the analysis of Table 1, it can be seen that in Example 2, the fluorine-doped diamond film (F-DLC) was lubricated with a fluorine-containing lubricating oil containing 5 wt.% perfluorobutanol and perfluoropolyether, and the friction coefficient was tested to be 0.01; Figure 2-3 From the analysis of Table 1, it can be seen that in Comparative Example 2, the fluorine-doped diamond film was lubricated with perfluoropolyether lubricating oil alone, and the tested friction coefficient was 0.02, which is almost twice the friction coefficient of Example 2. This result shows that the friction coefficient of F-DLC lubricated with perfluoropolyether alone is relatively high.

[0069] according to Figure 2From the analysis of Table 1, it can be seen that in Comparative Example 3, perfluorobutanol lubricating oil is used alone to lubricate the fluorine-doped diamond film, and the tested friction coefficient is 0.2. This result shows that although perfluorobutanol has good lubrication properties, when perfluorobutanol is used alone, its molecular structure may not be able to form an effective friction reaction film, resulting in a higher friction coefficient. In Example 2, perfluoropolyether is introduced, and the two form a synergistic effect, which can enhance the lubrication performance, promote the formation of a more uniform and stable lubrication film on the surface, and further reduce the friction coefficient.

[0070] according to Figure 2 From the analysis of Table 1, it can be seen that in Comparative Example 4, 5 wt.% perfluorobutanol and perfluoropolyether fluorine-containing lubricating oil is used to lubricate the ordinary diamond-like carbon film (DLC) without fluorine element doping. The tested friction coefficient is stable at 0.025, which is more than twice the friction coefficient of fluorine-doped DLC used in Example 2. This shows that the fluorine-containing lubricating oil provided by the present invention and the fluorine-doped DLC have a good synergistic effect. The combination of the two can improve the adsorption of the fluorine-containing lubricating oil on the surface of the fluorine-doped DLC and effectively improve the friction coefficient.

[0071] According to Table 1 and Figure 4 From the analysis, it can be seen that in Example 5, liquid lubricant containing hydroxyl and carboxyl groups is used to lubricate the fluorine-doped diamond-like film. Due to the large electronegativity of the fluorine element, the liquid lubricant containing hydroxyl and carboxyl groups is difficult to adsorb on the fluorine-doped diamond-like film and has no lubricating effect. Therefore, the friction coefficient is relatively high, and the tested friction coefficient is 0.1.

[0072] According to Table 1 and Figure 5 Analysis shows that in Comparative Example 6, the fluorine-doped diamond film (F-DLC) was lubricated with a fluorine-containing lubricant containing 50 wt.% perfluorobutanol and perfluoropolyether, and the friction coefficient was 0.06, while in Example 1, the fluorine-doped diamond film (F-DLC) was lubricated with a fluorine-containing lubricant containing 20 wt.% perfluorobutanol and perfluoropolyether, and the friction coefficient was 0.004. This shows that when the content of the lubricating additive in the fluorine-containing lubricant exceeds 20 wt.%, the friction coefficient is higher.

Claims

1. A fluorine-containing lubricating oil for fluorine-doped diamond-like carbon film, characterized in that: The fluorine-containing lubricating oil comprises a base lubricating oil and a lubricating additive, wherein the molecules of the lubricating additive contain hydroxyl groups and fluorine elements; Wherein, based on the mass of the fluorine-containing lubricating oil, the lubricating additive accounts for 1wt.%-20wt.%.

2. The fluorine-containing lubricating oil for fluorine-doped diamond-like carbon film according to claim 1, characterized in that: The lubricating additive is selected from one or a combination of two or more of perfluorobutanol, perfluoropentanol, 1H,1H,2H,2H-perfluorohexan-1-ol, and octafluoroheptanol; And / or, based on the mass of the fluorine-containing lubricating oil, the lubricating additive accounts for 5wt.%-10wt.%.

3. The fluorine-containing lubricating oil for fluorine-doped diamond-like carbon film according to claim 1, characterized in that: The base lubricating oil is perfluoropolyether.

4. A method for lubricating a fluorine-doped diamond-like carbon film, characterized in that: The steps include: The fluorine-doped diamond-like film is lubricated using the fluorine-containing lubricant according to any one of claims 1 to 3; preferably, the amount of the fluorine-containing lubricant is: per 1 cm 2 For the fluorine-doped diamond-like carbon film, use 5-30 μL of fluorine-containing lubricating oil.

5. The lubrication method of fluorine-doped diamond-like carbon film according to claim 4, characterized in that: The content of fluorine in the fluorine-doped diamond-like carbon film is 5%-20%, preferably 10%-15%.

6. The lubrication method of fluorine-doped diamond-like carbon film according to claim 4, characterized in that: The thickness of the fluorine-doped diamond-like carbon film is 800-1000 nm.

7. The lubrication method of fluorine-doped diamond-like carbon film according to claim 4, characterized in that: The fluorine-doped diamond-like carbon film has a Young's modulus of 10-50 GPa and a hardness of 1-7 GPa; preferably, the Young's modulus is 35 GPa and the hardness is 3.5 GPa.

8. The lubrication method of fluorine-doped diamond-like carbon film according to claim 4, characterized in that: The fluorine-doped diamond-like carbon film is deposited on the surface of a substrate material by chemical vapor deposition; preferably, the deposition time is 0.5-2 hours.

9. The lubrication method of fluorine-doped diamond-like carbon film according to claim 4, characterized in that: The lubrication method also includes a process of ultrasonically dispersing polytetrafluoroethylene nanoparticles in the fluorine-containing lubricating oil.

10. The lubrication method of fluorine-doped diamond-like carbon film according to claim 9, characterized in that: The particle size of the polytetrafluoroethylene nanoparticles is 2-3 μm; And / or, the mass ratio of the fluorine-containing lubricating oil to the polytetrafluoroethylene nanoparticles is (10-30):1, preferably 20:1; And / or, the ultrasonic dispersion time is 0.25-2h, preferably 1h; and / or, every 1 cm 2 For the fluorine-doped diamond-like carbon film, use 20 μL of fluorine-containing lubricating oil.

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