Solid-liquid composite superlubricity coating based on self-assembled monolayer and preparation method thereof

Abstract

The application belongs to the technical field of super-lubricating materials, and particularly relates to a solid-liquid composite super-lubricating coating based on a self-assembled monolayer and a preparation method thereof. The preparation method comprises the following steps: immersing a hydroxylated workpiece into an alkyltrichlorosilane reaction reagent, and obtaining a self-assembled monolayer on the surface of the workpiece after reaction and curing in an atmospheric environment; and coating a liquid lubricating medium on the surface of the workpiece with the self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer. The prepared solid-liquid composite super-lubricating coating based on the self-assembled monolayer can realize the super-lubricating behavior of a sliding part in a short running-in period in an atmospheric environment, greatly reduces the friction and wear of the sliding part, and improves the stability of a mechanical system.

Description

Technical Field

[0001] This invention belongs to the field of superlubricating materials technology, specifically relating to a solid-liquid composite superlubricating coating based on a self-assembled monomolecular film and its preparation method. Background Technology

[0002] In industrial applications, friction and wear between mechanical components lead to significant energy loss and mechanical failures. It is reported that friction accounts for approximately one-third of the world's energy consumption, while lubrication failure and wear cause more than 50% of overall equipment failures or major accidents. Therefore, developing efficient lubrication technologies is crucial for energy conservation and improving the service life and stability of mechanical equipment.

[0003] Superlubrication refers to a lubrication state where the coefficient of friction between objects in relative motion is less than 0.01, meaning the frictional force is almost zero or even completely absent. Achieving a stable superlubrication state between mechanical components can effectively reduce the negative effects of friction and wear, significantly improving the transmission efficiency and stability of mechanical systems. However, the inherent limitations of superlubrication technology severely hinder its practical application in industry. For example, solid superlubrication, an important form of superlubrication technology, is often limited to the micro-nano scale and is subject to severe environmental constraints; while liquid superlubrication, although achieving stable superlubricating behavior under macroscopic conditions, often uses acid-based / water-based lubricants and has a long break-in period, leading to serious corrosion and wear risks on the friction pair surfaces. To promote the practical industrial application of superlubrication technology, the development of novel superlubrication technologies is crucial.

[0004] In recent years, the emergence of solid-liquid composite superlubrication technology has brought new ideas to the development of superlubrication systems. It combines a solid surface with a liquid lubricating medium, retaining the advantages of liquid superlubrication technology, such as less environmental restriction and macroscopic stability in atmospheric environments, while also overcoming the drawbacks of severe wear and long break-in periods through active modification of the substrate surface. Currently, solid-liquid composite superlubrication technology has made significant progress, and various methods have been developed to explore the possibility of ultra-low friction behavior. For example, Chinese invention patent CN202111521225.8 discloses an ultra-low friction solid-liquid composite lubricating coating and its preparation method. A diamond-like carbon (DLC) coating is applied to the friction surfaces of the substrates, with a lubricating oil layer serving as an intermediate liquid phase between the DLC coatings. This technology achieves extremely low friction coefficients and wear rates by combining the DLC coating and the lubricating oil layer. Similarly, Chinese invention patent CN202310688021.6 discloses a solid-liquid composite superlubricating carbon-based coating for rubber surfaces and its preparation method. This method involves depositing a Ta-C thin film on a rubber substrate using magnetron sputtering, then constructing micron-sized pits on the film surface using laser etching, and spraying polymer-encapsulated lubricating oil nanocapsules into these pits. Finally, two-dimensional material nanosheets are sprayed onto the entire coating surface to obtain the solid-liquid composite superlubricating carbon-based coating. The synergistic effect of the surface two-dimensional material nanosheets and the lubricating oil achieves superlubricating behavior with a friction coefficient below 0.01. This research has not only achieved outstanding results but also greatly promoted the practical industrial application of superlubricating technology. However, current solid-liquid composite superlubricating technologies often require coating preparation or other surface treatments on the friction pair surfaces. This significantly alters the inherent properties of the substrate material surface and the assembly precision of mechanical components, hindering the widespread application of superlubricating technology in precision devices. Therefore, achieving ultra-low friction behavior of sliding components without altering the inherent properties of the material surface has become crucial for advancing solid-liquid composite superlubricating technology.

[0005] Therefore, this invention provides a solid-liquid composite superlubricating coating based on a self-assembled monomolecular film and its preparation method, which utilizes the composite lubrication effect of the self-assembled monomolecular film and the liquid lubricating medium to achieve macroscopically stable ultra-low friction behavior without a break-in period. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a solid-liquid composite superlubricating coating based on a self-assembled monolayer and its preparation method. This invention utilizes the combined lubrication effect of the self-assembled monolayer and the liquid lubricating medium to achieve superlubricating behavior in sliding components during a short break-in period, significantly reducing friction and wear in mechanical systems.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0008] The first objective of this invention is to provide a method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer, comprising the following steps:

[0009] Using a hydroxylated workpiece as a substrate, it is immersed in an alkyltrichlorosilane reaction reagent and reacted and cured under atmospheric conditions to obtain a self-assembled monomolecular film on the surface of the workpiece.

[0010] A liquid lubricating medium is coated onto the surface of a workpiece with a self-assembled monomolecular film to obtain a solid-liquid composite coating based on the self-assembled monomolecular film.

[0011] Furthermore, the coverage of the self-assembled monomolecular film on the workpiece is greater than 10%.

[0012] Furthermore, the alkyltrichlorosilane is a hydrocarbon chain trichlorosilane containing C1-18, with a methyl group at its end.

[0013] Furthermore, the liquid lubricating medium is one or more liquid alcohols, and the number of hydroxyl groups in the polyol is ≥3.

[0014] Furthermore, the reaction time under atmospheric conditions is ≥1 min, the curing temperature is 120℃, and the curing time is 1 h.

[0015] Furthermore, the preparation method of the alkyltrichlorosilane reaction reagent is as follows: add alkyltrichlorosilane to a solvent to prepare an alkyltrichlorosilane solution with a concentration of 0.01-1 wt%, and after ultrasonic dispersion, obtain the alkyltrichlorosilane reaction reagent.

[0016] Furthermore, the solvent is toluene or cyclohexane.

[0017] Furthermore, the workpiece is hydroxylated silicon dioxide, hydroxylated silicon wafer, hydroxylated mica sheet, hydroxylated aluminum oxide, or hydroxylated glass.

[0018] A second objective of this invention is to provide a solid-liquid composite superlubricating coating based on a self-assembled monolayer prepared by the above-described method. Under atmospheric conditions, when subjected to a load of no more than 3N and a sliding speed of no less than 10mm / s, the solid-liquid composite superlubricating coating can achieve superlubricating behavior with a friction coefficient of less than 0.01 for the sliding components.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) The solid-liquid composite superlubricating coating based on self-assembled monolayer prepared in this invention forms a self-assembled monolayer after being reacted and cured on the surface of the workpiece by alkyl trichlorosilane. By utilizing the composite lubrication effect of the self-assembled monolayer and the liquid lubricating medium, superlubricating behavior of sliding parts with short break-in period can be achieved in atmospheric environment. The coefficient of friction COF is less than 0.01, which greatly reduces the friction and wear of sliding parts and improves the stability of mechanical system.

[0021] (2) The self-assembled monomolecular film prepared in this invention has a thickness of only nanometers and has almost no effect on the morphology, mechanical properties and mechanical assembly precision of the substrate, and has extremely excellent industrial application value.

[0022] (3) The liquid lubricating medium used in this invention is an organic pure solution that does not contain water molecules, thus avoiding the risk of water corrosion to mechanical parts and the impact of water evaporation on the stability of lubrication behavior, thereby significantly improving the service life of the solid-liquid composite super lubricating coating. Attached Figure Description

[0023] Figure 1 This is a microscopic morphology diagram of the self-assembled monolayer constructed in Example 1 of the present invention.

[0024] Figure 2 This is a surface composition diagram of the self-assembled monolayer constructed in Example 1 of the present invention.

[0025] Figure 3 The diagram shows the ultra-low friction coefficient of the solid-liquid composite superlubricating coating based on a self-assembled monolayer prepared in Example 1 of this invention.

[0026] Figure 4 This is a diagram showing the ultra-low coefficient of friction of the lubricating coating prepared in Comparative Example 1 of the present invention.

[0027] Figure 5 This is a diagram showing the ultra-low friction coefficient of the lubricating coating prepared in Comparative Example 2 of the present invention.

[0028] Figure 6 The friction coefficient diagram is shown for the lubricating coating prepared in Comparative Example 4 of this invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0031] This invention provides a method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer, comprising the following steps:

[0032] The hydroxylated workpiece is placed in a reactor, and an alkyltrichlorosilane reaction reagent is poured in. The reaction is carried out under atmospheric conditions. After the reaction is completed, the workpiece is rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents from the surface of the workpiece. Then it is dried immediately and placed in an oven to cure, thus obtaining a workpiece with a self-assembled monomolecular film.

[0033] Liquid lubricating medium is drop-coated onto the surface of a workpiece with a self-assembled monomolecular film to obtain a solid-liquid composite coating based on the self-assembled monomolecular film.

[0034] This invention prepares a solid-liquid composite superlubricating coating based on a self-assembled monolayer. The self-assembled monolayer is formed by the reaction and curing of alkyl trichlorosilane on the workpiece surface. Utilizing the combined lubrication effect of the self-assembled monolayer and the liquid lubricating medium, superlubricating behavior with a short break-in period can be achieved for sliding components in atmospheric conditions, significantly reducing friction and wear and improving the stability of the mechanical system. The prepared self-assembled monolayer is only nanometer thick, having almost no impact on the morphology, mechanical properties, or mechanical assembly precision of the substrate, and possesses extremely high industrial application value.

[0035] In some specific embodiments, the coverage of the self-assembled monomolecular film on the workpiece is greater than 10% in order to achieve super-lubricating behavior.

[0036] In some specific embodiments, the alkyltrichlorosilane reactant is a hydrocarbon chain trichlorosilane containing C1-18 atoms, with a methyl group at the end. In this invention, the purpose of the alkyltrichlorosilane is to form a self-assembled monolayer after reaction and curing on the workpiece surface, thereby achieving superlubrication behavior of sliding components through combined lubrication with the liquid lubricating medium.

[0037] In some specific embodiments, the liquid lubricating medium is one or more liquid polyols, wherein the number of hydroxyl groups in the liquid polyol is ≥3, such as glycerol, butylene glycol, etc. The liquid lubricating medium used in this invention is a pure organic solution, free of water molecules, thus avoiding the risk of water corrosion to mechanical parts and the impact of water evaporation on the stability of lubrication behavior, thereby significantly improving the service life of the solid-liquid composite superlubricating coating.

[0038] In some specific embodiments, the reaction time under atmospheric conditions is ≥1 min, the curing temperature is 120℃, and the curing time is 1 h.

[0039] In some specific embodiments, the alkyltrichlorosilane reaction reagent is prepared by adding alkyltrichlorosilane to a solvent to prepare a 0.01wt%-1wt% alkyltrichlorosilane solution, and then dispersing it evenly by sonication for 30 minutes to obtain the alkyltrichlorosilane reaction reagent.

[0040] In some specific embodiments, the solvent is toluene or cyclohexane.

[0041] In some specific embodiments, the workpiece is hydroxylated silicon dioxide, hydroxylated silicon wafer, hydroxylated mica sheet, hydroxylated aluminum oxide, or hydroxylated glass.

[0042] This invention also provides a solid-liquid composite superlubricating coating based on a self-assembled monolayer prepared by the above-described method. The solid-liquid composite superlubricating coating can achieve superlubricating behavior of sliding parts during a short break-in period under atmospheric conditions, with a coefficient of friction (COF) below 0.01. During the use of the solid-liquid composite superlubricating coating, a workpiece with the coating is mounted on a friction testing machine. Under atmospheric conditions, a load not exceeding 3N and a sliding speed not less than 10mm / s are applied, resulting in ultra-low friction behavior with a coefficient of friction below 0.01.

[0043] The following specific examples will provide further explanation.

[0044] Example 1

[0045] A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer includes the following steps:

[0046] S1. Preparation of alkyltrichlorosilane reaction reagent: Add octadecyltrichlorosilane to cyclohexane to prepare a 0.1 wt% alkyltrichlorosilane organic solution, sonicate for 30 min to obtain a homogeneous reaction reagent.

[0047] S2. Preparation of self-assembled monolayers: Hydroxylated silica workpieces were placed in a reactor, and alkyltrichlorosilane reagents were added. The reaction was carried out under atmospheric conditions for 1 minute. After the reaction, the workpieces were rinsed sequentially with the solvent used in the reaction and then with ethanol to remove residual reagents from the surface. The workpieces were then immediately dried and placed in an oven to cure at 120°C for 1 hour, resulting in silica workpieces with a 31% coverage area and self-assembled monolayers. The morphology of the self-assembled monolayers is shown in the attached figure. Figure 1 The chemical composition is shown in the attached figure. Figure 2 As shown.

[0048] S3. Preparation of solid-liquid composite superlubricating coating—Glycerol liquid lubricating medium is drop-coated onto the surface of a silica workpiece with a self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer.

[0049] Friction test—The workpiece with the solid-liquid composite coating was mounted on a friction testing machine. Under atmospheric conditions, a load of 2N and a linear velocity of 18mm / s were applied to obtain macroscopically stable superlubricating behavior (cof = 0.008). The friction test results are as follows: Figure 3 As shown.

[0050] Example 2

[0051] A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer includes the following steps:

[0052] S1. Preparation of alkyltrichlorosilane reaction reagent: Add methyltrichlorosilane to cyclohexane to prepare a 0.1 wt% alkyltrichlorosilane organic solution, sonicate for 30 min to obtain a homogeneous reaction reagent.

[0053] S2. Preparation of self-assembled monolayer: The hydroxylated silica workpiece is placed in a reactor, and an alkyltrichlorosilane reaction reagent is poured in. The reaction is carried out under atmospheric conditions for 1 hour. After the reaction is completed, the workpiece is rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents on the surface of the workpiece. Then it is dried immediately and placed in an oven to cure at 120°C for 1 hour to obtain a silica workpiece with a coverage of more than 90% and a self-assembled monolayer.

[0054] S3. Preparation of solid-liquid composite superlubricating coating—Glycerol liquid lubricating medium is drop-coated onto the surface of a silica workpiece with a self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer.

[0055] Friction test—The workpiece with the solid-liquid composite coating is mounted on a friction testing machine and subjected to a load of 2N and a linear velocity of 18mm / s in an atmospheric environment to obtain macroscopically stable superlubricating behavior (cof=0.007).

[0056] Example 3

[0057] A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer includes the following steps:

[0058] S1. Preparation of alkyltrichlorosilane reaction reagent: Add octadecyltrichlorosilane to toluene to prepare a 1wt% alkyltrichlorosilane organic solution, sonicate for 30 min to obtain a uniformly mixed reaction reagent.

[0059] S2. Preparation of self-assembled monolayer: The hydroxylated silica workpiece is placed in a reactor, and an alkyltrichlorosilane reaction reagent is poured in. The reaction is carried out under atmospheric conditions for 10 minutes. After the reaction is completed, the workpiece is rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents on the surface of the workpiece. Then it is dried immediately and placed in an oven to cure at 120°C for 1 hour to obtain a silica workpiece with a coverage of more than 90%.

[0060] S3. Preparation of solid-liquid composite superlubricating coating—Glycerol liquid lubricating medium is coated onto the surface of a silica workpiece with a self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer.

[0061] Friction test—The workpiece with the solid-liquid composite coating is mounted on a friction testing machine and subjected to a load of 2N and a linear velocity of 18mm / s in an atmospheric environment to obtain macroscopically stable superlubricating behavior (cof=0.008).

[0062] Example 4

[0063] A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer includes the following steps:

[0064] S1. Preparation of alkyltrichlorosilane reaction reagent: Add octadecyltrichlorosilane to cyclohexane to prepare a 0.01wt% alkyltrichlorosilane organic solution, sonicate for 30 min to obtain a homogeneous reaction reagent;

[0065] S2. Preparation of self-assembled monolayer: The hydroxylated silica workpiece is placed in a reactor, and an alkyltrichlorosilane reaction reagent is poured in. The reaction is carried out under atmospheric conditions for 1 hour. After the reaction is completed, the workpiece is rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents on the surface of the workpiece. Then it is dried immediately and placed in an oven to cure at 120°C for 1 hour to obtain a silica workpiece with a coverage of more than 10% and a self-assembled monolayer.

[0066] S3. Preparation of solid-liquid composite superlubricating coating—Glycerol liquid lubricating medium is drop-coated onto the surface of a silica workpiece with a self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer.

[0067] Friction test—The workpiece with the solid-liquid composite coating is mounted on a friction testing machine and subjected to a load of 2N and a linear velocity of 18mm / s in an atmospheric environment to obtain macroscopically stable superlubricating behavior.

[0068] Comparative Example 1

[0069] A method for preparing a liquid lubricating medium coating includes the following steps:

[0070] Glycerol liquid lubricant is directly coated onto the surface of hydroxylated silica workpiece to obtain a workpiece containing only liquid lubricant.

[0071] Friction Test—A workpiece containing only liquid lubricant was mounted on a friction testing machine. Under atmospheric conditions, a load of 2N and a linear velocity of 18mm / s were applied. A stable ultra-low friction state was not obtained at room temperature (the friction coefficient curve fluctuated significantly and was higher than 0.05). The friction test results are as follows: Figure 4 As shown.

[0072] Comparative Example 2

[0073] A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer includes the following steps:

[0074] S1. Preparation of alkyltrichlorosilane reaction reagent: Add octadecyltrichlorosilane to cyclohexane to prepare 0.1wt% alkyltrichlorosilane organic solvent, sonicate for 30 min to obtain a uniformly mixed reaction reagent.

[0075] S2. Preparation of self-assembled monolayer: The hydroxylated silica workpiece was placed in a reactor, and an alkyltrichlorosilane reaction reagent was poured in. The reaction was carried out under atmospheric conditions for 5 seconds. After the reaction was completed, the workpiece was rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents on the surface of the workpiece. Then it was dried immediately and placed in an oven to cure at 120°C for 1 hour to obtain a silica workpiece with a coverage of 7.4%.

[0076] S3. Preparation of solid-liquid composite superlubricating coating—Glycerol liquid lubricating medium is coated onto the surface of a silica workpiece with a self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer.

[0077] Friction Test—The workpiece with the solid-liquid composite coating was mounted on a friction testing machine. Under atmospheric conditions, a load of 2N and a linear velocity of 18mm / s were applied. A stable ultra-low friction state was not obtained at room temperature (the friction coefficient curve fluctuated significantly and was higher than 0.05). The friction test results are as follows: Figure 5 As shown.

[0078] Comparative Example 3

[0079] A method for preparing a self-assembled monolayer includes the following steps:

[0080] S1. Preparation of alkyltrichlorosilane reaction reagent: Add octadecyltrichlorosilane to cyclohexane to prepare 0.1wt% alkyltrichlorosilane organic solvent, sonicate for 30 min to obtain a uniformly mixed reaction reagent.

[0081] S2. Preparation of self-assembled monolayer: The hydroxylated silica workpiece was placed in a reactor, and an alkyltrichlorosilane reaction reagent was poured in. The reaction was carried out under atmospheric conditions for 1 min. After the reaction was completed, the workpiece was rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents on the surface of the workpiece. Then it was dried immediately and placed in an oven to cure at 120°C for 1 h to obtain a silica workpiece with a coverage of 31%.

[0082] Friction test—The workpiece with the self-assembled monolayer film was mounted on the friction tester and subjected to a load of 2N and a linear velocity of 18mm / s in an atmospheric environment. At room temperature, a stable ultra-low friction state was not obtained (the friction coefficient curve fluctuated greatly and was as high as 0.6).

[0083] Comparative Example 4

[0084] A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer includes the following steps:

[0085] S1. Preparation of alkyltrichlorosilane reaction reagent: Add octadecyltrichlorosilane to cyclohexane to prepare 0.1wt% alkyltrichlorosilane organic solvent, sonicate for 30 min to obtain a uniformly mixed reaction reagent.

[0086] S2. Preparation of self-assembled monolayer: The hydroxylated silica workpiece was placed in a reactor, and an alkyltrichlorosilane reaction reagent was poured in. The reaction was carried out under atmospheric conditions for 1 min. After the reaction was completed, the workpiece was rinsed with the solvent and ethanol used in the reaction reagent to remove residual reagents on the surface of the workpiece. Then it was dried immediately and placed in an oven to cure at 120°C for 1 h to obtain a silica workpiece with a coverage of 31%.

[0087] S3. Preparation of solid-liquid composite superlubricating coating—Ethylene glycol liquid lubricating medium is drop-coated onto the surface of a silica workpiece with a self-assembled monolayer to obtain a solid-liquid composite coating based on the self-assembled monolayer.

[0088] Friction Test—The workpiece with the solid-liquid composite coating was mounted on a friction testing machine. Under atmospheric conditions, a load of 2N and a linear velocity of 18mm / s were applied. A stable ultra-low friction state was not obtained at room temperature (the friction coefficient curve fluctuated significantly and was higher than 0.15). The friction test results are as follows: Figure 6 As shown.

[0089] In summary, the solid-liquid composite superlubricating coating based on a self-assembled monolayer prepared in this invention utilizes the combined lubrication effect of the self-assembled monolayer and the liquid lubricating medium to achieve superlubricating behavior of sliding parts during a short break-in period in atmospheric environments. The coefficient of friction (COF) is below 0.01, significantly reducing friction and wear of sliding parts and improving the stability of mechanical systems. The prepared self-assembled monolayer is only nanometer thick, having almost no impact on the morphology, mechanical properties, or mechanical assembly precision of the substrate, thus possessing extremely high industrial application value.

[0090] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0091] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer, characterized in that, Includes the following steps: The hydroxylated workpiece is immersed in an alkyltrichlorosilane reaction reagent, and after the reaction is cured under atmospheric conditions, a self-assembled monomolecular film is obtained on the surface of the workpiece. Under atmospheric conditions, the reaction time is ≥1 min, the curing temperature is 120 ℃, and the curing time is 1 h; A liquid lubricating medium is coated onto the surface of a workpiece with a self-assembled monomolecular film to obtain a solid-liquid composite coating based on the self-assembled monomolecular film. The coverage of the self-assembled monomolecular film on the workpiece is greater than 10%; The liquid lubricating medium is one or more polyols, and the number of hydroxyl groups in the polyol is ≥3.

2. The method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer according to claim 1, characterized in that, The alkyltrichlorosilane is a hydrocarbon chain trichlorosilane containing C1-18, with a methyl group at its end.

3. The method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer according to claim 1, characterized in that, The preparation method of the alkyltrichlorosilane reaction reagent is as follows: add alkyltrichlorosilane to a solvent to prepare an alkyltrichlorosilane solution with a concentration of 0.01-1 wt%, and after ultrasonic dispersion, obtain the alkyltrichlorosilane reaction reagent.

4. The method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer according to claim 3, characterized in that, The solvent is toluene or cyclohexane.

5. The method for preparing a solid-liquid composite superlubricating coating based on a self-assembled monolayer according to claim 1, characterized in that, The workpiece is hydroxylated silicon dioxide, hydroxylated silicon wafer, hydroxylated mica sheet, hydroxylated aluminum oxide, or hydroxylated glass.

6. A solid-liquid composite superlubricating coating based on a self-assembled monolayer prepared by the preparation method according to any one of claims 1-5.

7. The solid-liquid composite superlubricating coating based on a self-assembled monomolecular film according to claim 6, characterized in that, The solid-liquid composite super-lubricating coating, under atmospheric conditions, with a load not exceeding 3 N and a sliding speed not less than 10 mm / s, can achieve super-lubricating behavior with a friction coefficient of less than 0.01 for sliding parts.

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