A wear-resistant self-healing composite lubricant and its preparation method

Abstract

This invention relates to the field of lubricating oil technology, and more particularly to a wear-resistant self-healing composite lubricating oil and its preparation method. The aforementioned wear-resistant self-healing composite lubricating oil comprises, by weight, the following raw materials: 500-1000 parts of base lubricating oil, 5-10 parts of graphene oxide, 0.1-1 parts of manganese salt, 1-5 parts of tetraethyl orthosilicate, 0.1-1 parts of coupling agent, 1-2 parts of dispersant, 1-2 parts of surfactant, and 1-2 parts of anti-wear agent. The lubricating oil of this invention exhibits excellent self-healing properties, providing repair and protection to worn surfaces. It not only significantly reduces the coefficient of friction and substantially lowers the surface roughness of worn surfaces, but also demonstrates high dispersion stability and synergistic effects among its components. This results in the repair and protection of long-term friction interfaces, thereby extending the service life of equipment.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil technology, and in particular to a wear-resistant self-healing composite lubricating oil and its preparation method. Background Technology

[0002] In modern industrial systems, friction and wear of mechanical equipment are core factors leading to energy waste and equipment failure. According to industry statistics, approximately 30% of global primary energy consumption directly results from energy loss during friction, while replacement costs for worn mechanical parts can account for more than 20% of the total life-cycle cost of equipment.

[0003] The economic losses caused by friction and wear are mainly manifested in: shortened equipment life, premature failure of key components, and reduced energy conversion efficiency. Traditional solutions mainly rely on lubricating oil to form a lubricating film to reduce the coefficient of friction, but the anti-wear performance and self-healing ability of existing lubricating oils are still significantly insufficient.

[0004] Existing commercial lubricants mainly consist of base oils (mineral oils / synthetic oils) and functional additives. These additives have limited functions, only slowing down the wear process and unable to repair existing surface damage. It is particularly noteworthy that uneven dispersion of solid additives in lubricants can actually exacerbate abrasive wear.

[0005] Graphene oxide, due to its unique two-dimensional structure, is considered an ideal lubricating material. However, van der Waals forces easily cause graphene sheets to stack, forming micron-sized aggregates. Furthermore, graphene oxide exhibits a repulsive effect with the oil phase, resulting in poor anti-wear and friction-reducing effects and inadequate lubrication. These factors are key limitations restricting its application in the lubricating oil field. Therefore, while maintaining the excellent properties of graphene oxide, improving its stable dispersibility in lubricating oils and enabling it to self-repair worn surfaces are urgent problems to be solved. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a wear-resistant self-healing composite lubricant and its preparation method.

[0007] A wear-resistant self-repairing composite lubricating oil, the raw materials of which include, by weight: 500-1000 parts of base lubricating oil, 5-10 parts of graphene oxide, 0.1-1 parts of manganese salt, 1-5 parts of tetraethyl orthosilicate, 0.1-1 parts of coupling agent, 1-2 parts of dispersant, 1-2 parts of surfactant, and 1-2 parts of anti-wear agent.

[0008] Preferably, the base oil is at least one of paraffinic mineral oil, ester oil, polybutene, and polyisobutylene.

[0009] Preferably, the manganese salt is manganese dihydrogen phosphate.

[0010] Preferably, the coupling agent is silane coupling agent KH-550.

[0011] Preferably, the dispersant is at least one of sodium hexametaphosphate, oleic acid, stearic acid, and polyethylene glycol.

[0012] Preferably, the anti-wear agent is at least one of triphenyl phosphate, alkyl phosphate, polyphosphoric acid, sulfurized fatty acid methyl ester, ammonium phosphate, and aryl phosphate.

[0013] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0014] S1. Add graphene oxide to water and ultrasonically disperse for 5-10 hours. Then add manganese salt and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 1-3 hours. Adjust the pH of the system to 8-9 and continue ultrasonic treatment for 5-10 hours. Filter, wash, calcine at 200-250℃ for 1-2 hours under nitrogen protection, cool to room temperature, and pulverize to obtain supported graphene.

[0015] S2. Add the supported graphene to the ethanol aqueous solution and stir evenly. Adjust the pH of the system to 8-9, add the coupling agent, stir at 50-80℃ for 5-10 hours, filter, wash, vacuum dry, and pulverize to obtain the graphene additive.

[0016] S3. Add dispersant, surfactant and anti-wear agent to base lubricating oil, stir at 50-60℃ for 20-30 minutes, add graphene additive while stirring, continue stirring for 1-3 hours after complete addition, and let stand for 10-20 hours.

[0017] Preferably, in S1, the ultrasonic dispersion frequency is 50-70kHz.

[0018] Preferably, in S1, the calcination method is calcination in a tubular furnace.

[0019] Preferably, in step S3, the graphene additive is added in 3-4 equal increments.

[0020] Beneficial effects:

[0021] This invention loads silica particles onto the surface of graphene oxide. The graphene oxide sheets and nano-silica particles work synergistically to reduce the coefficient of friction and improve anti-wear properties, giving the product excellent friction-reducing and anti-wear properties and significantly improving lubrication performance. Furthermore, by chemically bonding and grafting coupling agents, the stable compatibility of the powder in the base oil is effectively enhanced, significantly reducing agglomeration. At the same time, its flexible molecules can significantly enhance the strength of the adsorption film and significantly improve boundary lubrication.

[0022] The present invention also synergistically loads manganese-containing compounds onto graphene oxide sheets and enhances interfacial adsorption with coupling agents; during long-term friction, frictional heat and mechanical stress cause manganese compounds to deposit on the damaged surface to form a protective film, covering micro-scratches and slowing down further wear, thereby achieving surface protection and repair.

[0023] The lubricating oil of this invention has a good self-healing effect, which can repair and protect the worn surface. It can not only greatly reduce the coefficient of friction and significantly reduce the surface roughness of the worn surface, but also has high dispersion stability and synergistic effect among its components. It can repair and protect the long-term friction interface and improve the service life of the equipment.

[0024] The preparation method of this invention is simple, easy to mass-produce, low in cost, has good self-repair effect, can extend the service life of lubricating oil, and has significant friction reduction and anti-wear effects, making it suitable for large-scale promotion and use. Attached Figure Description

[0025] Figure 1 The graph shows a comparison of the friction coefficient and wear volume of the composite lubricating oils obtained in Example 5 and Comparative Examples 1-2.

[0026] Figure 2 The diagram shows a comparison of the self-healing properties of the composite lubricating oils obtained in Example 5 and Comparative Examples 1-2. Detailed Implementation

[0027] The present invention will be further explained below with reference to specific embodiments.

[0028] The paraffinic mineral oil used below was purchased from Shandong Mouyou Lubrication Technology Co., Ltd., model number 350SN.

[0029] Example 1

[0030] A wear-resistant self-healing composite lubricating oil, the raw materials of which include: 500g of paraffin-based mineral oil, 5g of graphene oxide, 0.1g of manganese dihydrogen phosphate, 1g of tetraethyl orthosilicate, 0.1g of silane coupling agent KH-550, 1g of sodium hexametaphosphate, 1g of Tween 80, and 1g of triphenyl phosphate.

[0031] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0032] S1. Add graphene oxide to 50g of deionized water and ultrasonically disperse it at a frequency of 50kHz for 5h. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 1h. Adjust the pH of the system to 8-9 with a 1mol / L sodium hydroxide solution and continue ultrasonic treatment for 5h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 200℃ for 1h under nitrogen protection, cool to room temperature, and pulverize through a 100-mesh sieve to obtain supported graphene.

[0033] S2. Add the loaded graphene to 50g of 50% ethanol aqueous solution and stir evenly. Adjust the pH of the system to 8-9 using 1mol / L sodium hydroxide solution. Add silane coupling agent KH-550 and stir at 50℃ for 5h. Filter, wash, vacuum dry, and place in a high-speed pulverizer for 5min at a pulverizing speed of 5000r / min to obtain graphene additive.

[0034] S3. Add sodium hexametaphosphate, Tween 80, and triphenyl phosphate to the paraffinic mineral oil. Stir at 50°C for 20 minutes. While stirring, add the graphene additive in three equal portions at intervals. After the addition is complete, continue stirring for 1 hour and let stand for 10 hours.

[0035] Example 2

[0036] A wear-resistant self-healing composite lubricant, the raw materials of which include: 1000g of paraffin-based mineral oil, 10g of graphene oxide, 1g of manganese dihydrogen phosphate, 5g of tetraethyl orthosilicate, 1g of silane coupling agent KH-550, 2g of stearic acid, 2g of Tween 80, and 2g of polyphosphoric acid.

[0037] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0038] S1. Add graphene oxide to 80g of deionized water and ultrasonically disperse it at a frequency of 70kHz for 10h. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 3h. Adjust the pH of the system to 8-9 with a 2mol / L sodium hydroxide solution and continue ultrasonic treatment for 10h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 250℃ for 2h under nitrogen protection, cool to room temperature, and pulverize through a 100-mesh sieve to obtain supported graphene.

[0039] S2. Add the loaded graphene to 80g of 60% ethanol aqueous solution and stir until homogeneous. Adjust the pH of the system to 8-9 using 2mol / L sodium hydroxide solution. Add silane coupling agent KH-550 and stir at 80℃ for 10h. Filter, wash, vacuum dry, and place in a high-speed pulverizer for 10min at a pulverizing speed of 10000r / min to obtain the graphene additive.

[0040] S3. Add stearic acid, Tween 80 and polyphosphoric acid to paraffinic mineral oil, stir at 60℃ for 30 minutes, add graphene additive in three equal portions at intervals while stirring, continue stirring for 3 hours after the addition is complete, and let stand for 20 hours.

[0041] Example 3

[0042] A wear-resistant, self-healing composite lubricant, the raw materials of which include: 700g paraffinic mineral oil, 9g graphene oxide, 0.3g manganese dihydrogen phosphate, 4g tetraethyl orthosilicate, 0.3g silane coupling agent KH-550, 1.8g PEG-3000, 1.2g Tween 80, and 1.8g sulfurized fatty acid methyl ester (German DOG, DeoAdd MD18).

[0043] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0044] S1. Add graphene oxide to 60g of deionized water and ultrasonically disperse it at a frequency of 65kHz for 7h. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 2.5h. Adjust the pH of the system to 8-9 with a 1.2mol / L sodium hydroxide solution and continue ultrasonic treatment for 9h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 210℃ for 100min under nitrogen protection, cool to room temperature, pulverize and pass through a 100-mesh sieve to obtain supported graphene.

[0045] S2. Add the loaded graphene to 60g of 58% ethanol aqueous solution and stir until homogeneous. Adjust the pH of the system to 8-9 using 1.3mol / L sodium hydroxide solution. Add silane coupling agent KH-550 and stir at 70℃ for 7h. Filter, wash, vacuum dry, and place in a high-speed pulverizer for 9min at a pulverizing speed of 7000r / min to obtain the graphene additive.

[0046] S3. Add PEG-3000, Tween 80, and sulfurized fatty acid methyl ester to paraffinic mineral oil. Stir at 58°C for 22 minutes. While stirring, add graphene additive in four equal portions at intervals. After the addition is complete, continue stirring for 2.5 hours and let stand for 12 hours.

[0047] Example 4

[0048] A wear-resistant self-healing composite lubricant, the raw materials of which include: 900g of paraffinic mineral oil, 7g of graphene oxide, 0.7g of manganese dihydrogen phosphate, 2g of tetraethyl orthosilicate, 0.7g of silane coupling agent KH-550, 1.2g of PEG-3000, 1.8g of Tween 80, and 1.2g of tributyl phosphate.

[0049] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0050] S1. Add graphene oxide to 70g of deionized water and ultrasonically disperse it at a frequency of 55kHz for 9h. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 1.5h. Adjust the pH of the system to 8-9 with a sodium hydroxide solution of concentration of 1.8mol / L and continue ultrasonic treatment for 7h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 230℃ for 80min under nitrogen protection, cool to room temperature, pulverize and pass through a 100-mesh sieve to obtain supported graphene.

[0051] S2. Add the loaded graphene to 70g of 52% ethanol aqueous solution and stir until homogeneous. Adjust the pH of the system to 8-9 using 1.7mol / L sodium hydroxide solution. Add silane coupling agent KH-550 and stir at 60℃ for 9h. Filter, wash, vacuum dry, and place in a high-speed pulverizer for 7min at a pulverizing speed of 9000r / min to obtain the graphene additive.

[0052] S3. Add PEG-3000, Tween 80 and tributyl phosphate to the paraffinic mineral oil. Stir at 52°C for 28 minutes. While stirring, add graphene additive in four equal portions at intervals. After the addition is complete, continue stirring for 1.5 hours and let stand for 18 hours.

[0053] Example 5

[0054] A wear-resistant self-healing composite lubricant, the raw materials of which include: 800g of paraffin-based mineral oil, 8g of graphene oxide, 0.5g of manganese dihydrogen phosphate, 3g of tetraethyl orthosilicate, 0.5g of silane coupling agent KH-550, 1.5g of PEG-3000, 1.5g of Tween 80, and 1.5g of a mixture of phosphate amines (BASF, IRGALUBE349).

[0055] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0056] S1. Add graphene oxide to 65g of deionized water and ultrasonically disperse it at a frequency of 60kHz for 8h. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 2h. Adjust the pH of the system to 8-9 with a 1.5mol / L sodium hydroxide solution and continue ultrasonic treatment for 8h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 220℃ for 90min under nitrogen protection, cool to room temperature, pulverize and pass through a 100-mesh sieve to obtain supported graphene.

[0057] S2. Add the loaded graphene to 65g of 55% ethanol aqueous solution and stir until homogeneous. Adjust the pH of the system to 8-9 using 1.5mol / L sodium hydroxide solution. Add silane coupling agent KH-550 and stir at 65℃ for 8h. Filter, wash, vacuum dry, and place in a high-speed pulverizer for 8min at a pulverizing speed of 8000r / min to obtain the graphene additive.

[0058] S3. Add a mixture of PEG-3000, Tween 80 and ammonium phosphate to the paraffinic mineral oil. Stir at 55°C for 25 minutes. While stirring, add the graphene additive in four equal portions at intervals. After the addition is complete, continue stirring for 2 hours and let stand for 15 hours.

[0059] Comparative Example 1

[0060] A wear-resistant self-healing composite lubricant, the raw materials of which include: 800g of paraffin-based mineral oil, 8g of graphene oxide, 0.5g of manganese dihydrogen phosphate, 3g of tetraethyl orthosilicate, 0.5g of silane coupling agent KH-550, 1.5g of PEG-3000, 1.5g of Tween 80, and 1.5g of a mixture of phosphate amines (BASF, IRGALUBE349).

[0061] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0062] S1. Add graphene oxide to 65g of deionized water and ultrasonically disperse it at a frequency of 60kHz for 8h. Add tetraethyl orthosilicate and continue ultrasonic treatment for 2h. Adjust the pH of the system to 8-9 with a 1.5mol / L sodium hydroxide solution and continue ultrasonic treatment for 8h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 220℃ for 90min under nitrogen protection, cool to room temperature, pulverize and pass through a 100-mesh sieve to obtain supported graphene.

[0063] S2. Add the loaded graphene and manganese dihydrogen phosphate to 65g of 55% ethanol aqueous solution and stir until homogeneous. Adjust the pH of the system to 8-9 using 1.5mol / L sodium hydroxide solution. Add silane coupling agent KH-550 and stir at 65℃ for 8h. Filter, wash, vacuum dry, and place in a high-speed pulverizer for 8min at a pulverizing speed of 8000r / min to obtain the graphene additive.

[0064] S3. Add a mixture of PEG-3000, Tween 80 and ammonium phosphate to the paraffinic mineral oil. Stir at 55°C for 25 minutes. While stirring, add the graphene additive in four equal portions at intervals. After the addition is complete, continue stirring for 2 hours and let stand for 15 hours.

[0065] Comparative Example 2

[0066] A wear-resistant self-healing composite lubricant, the raw materials of which include: 800g of paraffin-based mineral oil, 8g of graphene oxide, 0.5g of manganese dihydrogen phosphate, 3g of tetraethyl orthosilicate, 0.5g of silane coupling agent KH-550, 1.5g of PEG-3000, 1.5g of Tween 80, and 1.5g of a mixture of phosphate amines (BASF, IRGALUBE349).

[0067] The preparation method of the above-mentioned wear-resistant self-repairing composite lubricating oil includes the following steps:

[0068] S1. Add graphene oxide to 65g of deionized water and ultrasonically disperse it at a frequency of 60kHz for 8h. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 2h. Adjust the pH of the system to 8-9 with a 1.5mol / L sodium hydroxide solution and continue ultrasonic treatment for 8h. Filter, wash with deionized water and ethanol, calcine in a tube furnace at 220℃ for 90min under nitrogen protection, cool to room temperature, pulverize and pass through a 100-mesh sieve to obtain supported graphene.

[0069] S2. Add a mixture of PEG-3000, Tween 80, and ammonium phosphate to the paraffinic mineral oil. Stir at 55°C for 25 minutes. While stirring, add the loaded graphene and silane coupling agent KH-550 in four equal portions at intervals. After the addition is complete, continue stirring for 2 hours and let stand for 15 hours.

[0070] The composite lubricating oils obtained in Example 5 and Comparative Examples 1-2 were allowed to stand for 72 hours, and their morphology was observed. They were then ultrasonically treated for 4 hours (50 kHz), centrifuged at 2000 r / min for 30 min, and allowed to stand for another 72 hours before their morphology was observed again. The results are shown in Table 1.

[0071] Table 1. Condition of each group of compound lubricating oils

[0072]

[0073] As shown in Table 1, the composite lubricating oil obtained in Example 5 has the most stable properties.

[0074] Friction tests were conducted on the composite lubricating oils obtained in Example 5 and Comparative Examples 1-2 using a fretting friction and wear tester. The test conditions were as follows: ball-disc contact mode; the upper test ball had a diameter of Ф10 mm, and the mating disk had a diameter of Ф24.0 mm and a thickness of 7.9 mm, both made of GCr15 stainless steel; the test load was 20 N, the frequency was 25 Hz, the amplitude was 1 mm, the period was 30 min, and the temperature was 25 °C. After the friction test, the wear volume was measured using MicroXAM-3D.

[0075] The result is as follows Figure 1As shown, the composite lubricating oil obtained in Example 5 has the lowest coefficient of friction and wear volume, which is better than Comparative Examples 1-2 (P<0.05).

[0076] The cylinder liner-piston ring friction test system of an automobile engine after running for a period of time was used as the test object. At this time, the roughness R of the worn surface of each group of cylinder liners was measured. a The roughness was 1.5 ± 0.2 μm. The composite lubricating oils obtained in Example 5 and Comparative Examples 1-2 were used in the above-mentioned automobile engine cylinder liner-piston ring friction test system for continuous operation for 12 hours, and the surface roughness of the cylinder liner was measured again.

[0077] The results are as follows Figure 2 As shown, the composite lubricating oil obtained in Example 5 minimizes the surface roughness of the cylinder liner and exhibits excellent self-repairing function.

[0078] The reasons for the above results are as follows: This invention loads silica particles onto the surface of graphene oxide. The graphene oxide sheets and nano-silica particles synergistically reduce the coefficient of friction and improve anti-wear properties, giving the product excellent friction-reducing and anti-wear properties and significantly improving lubrication performance. Furthermore, through chemical bonding and grafting coupling agents, the stable compatibility of the powder in the base oil is effectively enhanced, significantly reducing agglomeration. At the same time, its flexible molecules can significantly enhance the strength of the adsorption film, significantly improving boundary lubrication. This invention also synergistically loads manganese-containing compounds onto the graphene oxide sheets, and in conjunction with coupling agents, enhances interfacial adsorption. During long-term friction, frictional heat and mechanical stress cause manganese compounds to deposit on the damaged surface to form a protective film, covering micro-scratches and slowing down further wear, thereby achieving surface protection and repair.

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A wear-resistant, self-healing composite lubricant, characterized in that, Its raw materials, by weight, include: 500-1000 parts of base lubricating oil, 5-10 parts of graphene oxide, 0.1-1 parts of manganese dihydrogen phosphate, 1-5 parts of tetraethyl orthosilicate, 0.1-1 parts of coupling agent, 1-2 parts of dispersant, 1-2 parts of surfactant, and 1-2 parts of anti-wear agent. The following steps are used to prepare it: S1. Add graphene oxide to water and ultrasonically disperse for 5-10 hours. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 1-3 hours. Adjust the pH of the system to 8-9 and continue ultrasonic treatment for 5-10 hours. Filter, wash, calcine at 200-250℃ for 1-2 hours under nitrogen protection, cool to room temperature, and pulverize to obtain supported graphene. S2. Add the supported graphene to the ethanol aqueous solution and stir evenly. Adjust the pH of the system to 8-9, add the coupling agent, stir at 50-80℃ for 5-10 hours, filter, wash, vacuum dry, and pulverize to obtain the graphene additive. S3. Add dispersant, surfactant and anti-wear agent to base lubricating oil, stir at 50-60℃ for 20-30 minutes, add graphene additive while stirring, continue stirring for 1-3 hours after complete addition, and let stand for 10-20 hours.

2. The wear-resistant self-repairing composite lubricating oil according to claim 1, characterized in that, The base oil is at least one of paraffinic mineral oil, ester oil, polybutene, and polyisobutylene.

3. The wear-resistant self-healing composite lubricating oil according to claim 1, characterized in that, The coupling agent is silane coupling agent KH-550.

4. The wear-resistant self-repairing composite lubricating oil according to claim 1, characterized in that, The dispersant is at least one of sodium hexametaphosphate, oleic acid, stearic acid, and polyethylene glycol.

5. The wear-resistant self-healing composite lubricating oil according to claim 1, characterized in that, The anti-wear agent is at least one of triphenyl phosphate, alkyl phosphate, polyphosphoric acid, sulfurized fatty acid methyl ester, and ammonium phosphate.

6. A method for preparing a wear-resistant self-repairing composite lubricating oil as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Add graphene oxide to water and ultrasonically disperse for 5-10 hours. Then add manganese dihydrogen phosphate and tetraethyl orthosilicate sequentially and continue ultrasonic treatment for 1-3 hours. Adjust the pH of the system to 8-9 and continue ultrasonic treatment for 5-10 hours. Filter, wash, calcine at 200-250℃ for 1-2 hours under nitrogen protection, cool to room temperature, and pulverize to obtain supported graphene. S2. Add the supported graphene to the ethanol aqueous solution and stir evenly. Adjust the pH of the system to 8-9, add the coupling agent, stir at 50-80℃ for 5-10 hours, filter, wash, vacuum dry, and pulverize to obtain the graphene additive. S3. Add dispersant, surfactant and anti-wear agent to base lubricating oil, stir at 50-60℃ for 20-30 minutes, add graphene additive while stirring, continue stirring for 1-3 hours after complete addition, and let stand for 10-20 hours.

7. The preparation method of the wear-resistant self-repairing composite lubricating oil according to claim 6, characterized in that, In S1, the ultrasonic dispersion frequency is 50-70kHz.

8. The preparation method of the wear-resistant self-repairing composite lubricating oil according to claim 6, characterized in that, In S1, the calcination method is calcination in a tubular furnace.

9. The preparation method of the wear-resistant self-repairing composite lubricating oil according to claim 6, characterized in that, In S3, the graphene additive is added in 3-4 equal-amount intervals.

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