Nanometer graphene lubricating oil and preparation method thereof

Abstract

The application discloses a kind of nano graphene lubricating oil and preparation method thereof, it is related to lubricating oil technical field.The application first with modified zirconium-titanium composite particles as catalyst to catalytically synthesize base oil, improve heat resistance effect;Then under the assistance of microwave, graphene is stripped to improve the dispersibility of graphene in lubricating oil, simultaneously with the surface of modified zirconium-titanium particles form hydrogen bond network, reduce fatigue wear, prolong service life, on this basis, particle and graphene produce electrochemistry deposition in the process of friction, reach the effect of self-repairing.Modified zirconium-titanium composite particles are first by precursor sol injection pre-cooled liquid nitrogen copper mould, quick freezing, vacuum sublimation drying removes ice crystal, forms snowflake-like hierarchical porous structure, improves lubricating effect;Then low-temperature annealing, form Zr-O-Ti mixed oxide framework, effectively inhibit pore collapse, prolong service life;Again through surface hydroxyl and capillary action, adsorb ionic liquid to form coating, enhance lubricating effect.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil technology, specifically to a nano-graphene lubricating oil and its preparation method. Background Technology

[0002] In today's industrial production and high-end manufacturing sectors, lubricating oil plays a crucial role, serving as a key material for ensuring the efficient and stable operation of machinery. The performance of lubricating oil directly affects equipment lifespan, energy efficiency, and environmental safety. Among the many improved varieties of lubricating oil, nano-graphene lubricating oil, due to the unique two-dimensional structure and superior performance of graphene, is widely considered an important upgraded alternative to traditional lubricating oil. Nevertheless, nano-graphene lubricating oil currently faces some significant technical obstacles in practical applications, hindering the full realization of its theoretical advantages in practice.

[0003] The improved lubrication performance of nano-graphene lubricants is limited by several factors. First, graphene's dispersion stability in base oils is insufficient, easily agglomerating into micron-sized particles, which can actually increase abrasive wear on the friction surfaces. Second, the interfacial bonding force between graphene and metal surfaces is relatively weak, making it difficult to form a stable physical adsorption film on metal surfaces, thus leading to lubrication failure under high-load operating conditions. For example, in a bench test of an automotive engine, it was found that when 0.5% graphene was added to the lubricant, under high temperature of 150℃ and load of 1000N, its coefficient of friction was only reduced by 8% compared to fully synthetic oil, a result far from the theoretically predicted reduction of 30%. Furthermore, the compatibility issues between graphene and traditional lubricant additives (such as ZDDP) limit the potential synergistic effect between them, further weakening the friction-reducing and anti-wear effects of nano-graphene lubricants. Summary of the Invention

[0004] The purpose of this invention is to provide a nano-graphene lubricating oil and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a nano-graphene lubricating oil, comprising the following preparation steps by weight:

[0006] (1) Under a nitrogen atmosphere, zirconium-titanium porous particles are placed in a tube furnace, heated to 180-240℃ for 2-6 hours, then naturally cooled to room temperature, immersed in an ionic liquid, sonicated at 30kHz for 30-50 minutes, filtered to collect the solid, and dried in an oven at 50℃ for 16-24 hours to obtain modified zirconium-titanium composite particles.

[0007] (2) The modified zirconium-titanium composite particles and α-olefins are mixed evenly in a reactor, hydrogen is introduced to a pressure of 5 MPa, the temperature is raised to 150-210℃, the reaction is carried out for 8-12 hours, and the mixture is naturally cooled to room temperature to obtain the base oil.

[0008] (3) Mix the nano-graphene with the base oil evenly, place it in a microwave reactor, and react for 1-3 minutes at a power of 800W and a frequency of 2.45GHz. Add 10wt% boronized polyisobutylene bis(succinimide), 0.9wt% polymethyl methacrylate, 0.4wt% polyether defoamer, 1wt% magnesium salt detergent, and 30wt% linseed oil by weight of the base oil, and stir evenly to obtain nano-graphene lubricating oil.

[0009] Further, the preparation steps of the zirconium-titanium porous particles in step (1) are as follows: the precursor gel is injected into a copper mold, frozen in liquid nitrogen for 5 to 15 minutes, and then transferred to a vacuum freeze dryer for sublimation and de-icing for 48 to 60 hours to obtain zirconium-titanium porous particles.

[0010] Furthermore, the preparation steps of the precursor gel are as follows: dissolve 5-9 parts of zirconium oxychloride and 4-6 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjust the pH to 3-4 with 0.5 mol / L nitric acid, and stir at 100 rpm for 6-10 h to obtain the precursor gel.

[0011] Furthermore, the parameters of the vacuum freeze dryer are: temperature -50℃ and pressure 10Pa.

[0012] Furthermore, the heating rate in step (1) is 10°C / min.

[0013] Furthermore, the ionic liquid in step (1) is selected from either 1-butyl-3-methylimidazolium tetrafluoroborate or 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide.

[0014] Furthermore, the mass ratio of the modified zirconium-titanium composite particles to α-olefins in step (2) is (0.01~0.07):1.

[0015] Furthermore, the particle size of the nanographene in step (3) is 5-25 nm.

[0016] Furthermore, the mass ratio of the nano-graphene to the base oil in step (3) is (0.001~0.01):1.

[0017] Furthermore, a nano-graphene lubricating oil is prepared according to any of the preparation methods described above.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0019] This invention first uses modified zirconium-titanium composite particles as a catalyst to synthesize base oil through a catalytic reaction. This process effectively reduces branched and unsaturated structures in the base oil, thereby significantly increasing its thermal decomposition temperature. By suppressing free radical chain decomposition and breakage, this invention further enhances the heat resistance of the base oil. Subsequently, under microwave assistance, graphene is exfoliated. This process preserves the active carboxyl functional groups between the graphene layers, greatly improving the dispersibility of graphene in the lubricating oil. Simultaneously, a hydrogen bond network forms between the surface of the modified zirconium-titanium particles and the graphene. This structure achieves a graphene-carrying effect, effectively reducing fatigue wear caused by friction, thereby indirectly extending the service life of the lubricating oil. Furthermore, the interaction between the modified zirconium-titanium particles and graphene during friction produces an electrochemical deposition phenomenon. This phenomenon helps repair microcracks on the metal surface, achieving a self-healing function for the lubricating oil.

[0020] In the preparation of modified zirconium-titanium composite particles, the precursor sol was first injected into a pre-cooled liquid nitrogen copper mold. Ice crystals were removed through rapid freezing and vacuum sublimation drying, resulting in a snowflake-like hierarchical porous structure. This unique structure constructs micro-nano-scale micro-oil reservoirs, which, under the activation of frictional heat, continuously release lubricating molecules through capillary action, significantly improving the lubrication effect of the lubricating oil. Next, a Zr-O-Ti mixed oxide framework was formed through low-temperature annealing, which effectively suppressed pore collapse. Furthermore, the semiconductor properties of the mixed oxides generated an electron cloud shielding effect at the friction interface, effectively reducing metal-to-metal adhesion and further extending the service life of the lubricating oil. Finally, through surface hydroxyl groups and capillary action, an adsorbed ionic liquid formed a coating layer, which enhanced the dispersion stability of graphene and created an interfacial electric double layer effect, further enhancing the lubrication effect of the lubricating oil. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the high and low temperature resistant and anti-wear lubricating oil prepared in the following embodiments are as follows:

[0023] Four-ball load capacity and wear scar diameter: Examples and comparative examples of the same mass were tested in accordance with standard GB / T3142.

[0024] Thermal decomposition temperature: Examples and comparative examples of the same mass were tested according to standard ASTM E2550.

[0025] Improved repair performance: The same mass of the example and comparative examples were ground on the metal surface for 30 minutes, and the repair rate of the metal surface was analyzed by spectral analysis.

[0026] Example 1

[0027] (1) Dissolve 5 parts zirconium oxychloride and 4 parts tetrabutyl titanate in 90 parts anhydrous ethanol, adjust the pH to 3 with 0.5 mol / L nitric acid, and stir at 100 rpm for 6 h to obtain the precursor gel.

[0028] (2) The precursor gel was injected into a copper mold and frozen in liquid nitrogen for 5 min. Then it was transferred to a vacuum freeze dryer and sublimated and de-iced at -50℃ and 10 Pa for 48 h to obtain zirconium-titanium porous particles.

[0029] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace and heated to 180°C at a rate of 10°C / min for 2 hours. After that, they were naturally cooled to room temperature and immersed in 1-butyl-3-methylimidazolium tetrafluoroborate. They were sonicated at 30 kHz for 30 minutes, the solid was filtered and collected, and dried in an oven at 50°C for 16 hours to obtain modified zirconium-titanium composite particles.

[0030] (4) The modified zirconium-titanium composite particles and α-olefins were mixed evenly in a reaction vessel at a mass ratio of 0.01:1. Hydrogen gas was introduced to a pressure of 5 MPa, the temperature was raised to 150°C, the reaction was carried out for 8 hours, and the mixture was naturally cooled to room temperature to obtain the base oil.

[0031] (5) Mix 5nm nano-graphene with base oil at a mass ratio of 0.001:1, place in a microwave reactor, react for 1 min at a power of 800W and a frequency of 2.45GHz, add 10wt% boronized polyisobutylene bis(succinimide), 0.9wt% polymethyl methacrylate, 0.4wt% polyether defoamer, 1wt% magnesium salt detergent, and 30wt% linseed oil, stir evenly to obtain nano-graphene lubricating oil;

[0032] The polymethacrylate was purchased from Romex GmbH, Germany, model SCR-168A;

[0033] The magnesium salt detergent was purchased from Chevron, model OLOA182.

[0034] Example 2

[0035] (1) Dissolve 7 parts zirconium oxychloride and 5 parts tetrabutyl titanate in 90 parts anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 h to obtain the precursor gel.

[0036] (2) The precursor gel was injected into a copper mold and frozen in liquid nitrogen for 10 min. Then it was transferred to a vacuum freeze dryer and sublimated and de-iced at -50℃ and 10 Pa for 54 h to obtain zirconium-titanium porous particles.

[0037] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace and heated to 210°C at a rate of 10°C / min for 4 hours. After that, they were naturally cooled to room temperature and immersed in 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt. The particles were sonicated at 30 kHz for 40 minutes, the solid was collected by filtration, and dried in an oven at 50°C for 20 hours to obtain modified zirconium-titanium composite particles.

[0038] (4) The modified zirconium-titanium composite particles and α-olefins were mixed evenly in a reaction vessel at a mass ratio of 0.04:1. Hydrogen gas was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, and the reaction was carried out for 10 hours. The mixture was then naturally cooled to room temperature to obtain the base oil.

[0039] (5) Mix 15nm nano-graphene with base oil at a mass ratio of 0.005:1, place in a microwave reactor, and react for 2 minutes at a power of 800W and a frequency of 2.45GHz. Add 10wt% boronized polyisobutylene bis(succinimide), 0.9wt% polymethyl methacrylate, 0.4wt% polyether defoamer, 1wt% magnesium salt detergent, and 30wt% linseed oil, and stir evenly to obtain nano-graphene lubricating oil.

[0040] The polymethacrylate was purchased from Romex GmbH, Germany, model SCR-168A;

[0041] The magnesium salt detergent was purchased from Chevron, model OLOA182.

[0042] Example 3

[0043] (1) Dissolve 9 parts zirconium oxychloride and 6 parts tetrabutyl titanate in 90 parts anhydrous ethanol, adjust the pH to 4 with 0.5 mol / L nitric acid, and stir at 100 rpm for 10 h to obtain the precursor gel.

[0044] (2) The precursor gel was injected into a copper mold and frozen in liquid nitrogen for 15 min. Then it was transferred to a vacuum freeze dryer and sublimated and de-iced at -50℃ and 10 Pa for 60 h to obtain zirconium-titanium porous particles.

[0045] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace and heated to 240°C at a rate of 10°C / min for 6 hours. After cooling to room temperature, they were immersed in 1-butyl-3-methylimidazolium tetrafluoroborate, sonicated at 30 kHz for 50 minutes, filtered to collect the solid, and dried in an oven at 50°C for 24 hours to obtain modified zirconium-titanium composite particles.

[0046] (4) The modified zirconium-titanium composite particles and α-olefins were mixed evenly in a reaction vessel at a mass ratio of 0.07:1. Hydrogen gas was introduced to a pressure of 5 MPa, the temperature was raised to 210°C, and the reaction was carried out for 12 hours. The mixture was then naturally cooled to room temperature to obtain the base oil.

[0047] (5) Graphene nanoparticles with a particle size of 25 nm were mixed with base oil at a mass ratio of 0.01:1 and placed in a microwave reactor. The mixture was reacted for 3 min at a power of 800 W and a frequency of 2.45 GHz. 10 wt% of boronized polyisobutylene bis(succinimide), 0.9 wt% of polymethyl methacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent and 30 wt% of linseed oil were added and stirred evenly to obtain graphene nanoparticle lubricating oil.

[0048] The polymethacrylate was purchased from Romex GmbH, Germany, model SCR-168A;

[0049] The magnesium salt detergent was purchased from Chevron, model OLOA182.

[0050] Comparative Example 1

[0051] (1) Aluminum chloride and α-olefin were mixed evenly in a reaction vessel at a mass ratio of 0.04:1. Hydrogen gas was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, the reaction was carried out for 10 h, and the mixture was naturally cooled to room temperature to obtain the base oil.

[0052] (2) Graphene nanoparticles with a particle size of 15 nm were mixed with base oil at a mass ratio of 0.005:1 and placed in a microwave reactor. The mixture was reacted for 2 min at a power of 800 W and a frequency of 2.45 GHz. Then, 10 wt% boronized polyisobutylene bis(succinimide), 0.9 wt% polymethacrylate, 0.4 wt% polyether defoamer, 1 wt% magnesium salt detergent, and 30 wt% linseed oil were added and stirred until homogeneous to obtain the graphene nanoparticle lubricating oil.

[0053] Comparative Example 2

[0054] (1) Dissolve 7 parts zirconium oxychloride and 5 parts tetrabutyl titanate in 90 parts anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 h to obtain the precursor gel.

[0055] (2) The precursor gel was injected into a copper mold and frozen in liquid nitrogen for 10 min. Then it was transferred to a vacuum freeze dryer and sublimated and de-iced at -50℃ and 10 Pa for 54 h to obtain zirconium-titanium porous particles.

[0056] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace and heated to 210°C at a rate of 10°C / min for 4 hours. After that, they were naturally cooled to room temperature and immersed in 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt. The particles were sonicated at 30 kHz for 40 minutes, the solid was collected by filtration, and dried in an oven at 50°C for 20 hours to obtain modified zirconium-titanium composite particles.

[0057] (4) The modified zirconium-titanium composite particles and α-olefins were mixed evenly in a reaction vessel at a mass ratio of 0.04:1. Hydrogen gas was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, and the reaction was carried out for 10 hours. The mixture was then naturally cooled to room temperature to obtain the base oil.

[0058] (5) Mix 15nm nano-graphene with base oil at a mass ratio of 0.005:1, add 10wt% boronized polyisobutylene bis(succinimide), 0.9wt% polymethyl methacrylate, 0.4wt% polyether defoamer, 1wt% magnesium salt detergent, and 30wt% linseed oil, and stir until homogeneous to obtain nano-graphene lubricating oil.

[0059] Comparative Example 3

[0060] (1) Dissolve 7 parts zirconium oxychloride and 5 parts tetrabutyl titanate in 90 parts anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 h to obtain the precursor gel.

[0061] (2) Under a nitrogen atmosphere, the precursor gel was placed in a tube furnace and heated to 410°C at a rate of 10°C / min for 4 hours. After cooling to room temperature, it was immersed in 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt, sonicated at 30 kHz for 40 minutes, the solid was collected by filtration and dried in an oven at 50°C for 20 hours to obtain modified zirconium-titanium composite particles.

[0062] (3) The modified zirconium-titanium composite particles and α-olefins were mixed evenly in a reactor at a mass ratio of 0.04:1. Hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, and the reaction was carried out for 10 hours. The mixture was then naturally cooled to room temperature to obtain the base oil.

[0063] (4) Graphene nanoparticles with a particle size of 15 nm were mixed with base oil at a mass ratio of 0.005:1 and placed in a microwave reactor. The mixture was reacted for 2 min at a power of 800 W and a frequency of 2.45 GHz. 10 wt% of boronized polyisobutylene bis(succinimide), 0.9 wt% of polymethyl methacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent, and 30 wt% of linseed oil were added and stirred evenly to obtain graphene nanoparticle lubricating oil.

[0064] Comparative Example 4

[0065] (1) Dissolve 7 parts zirconium oxychloride and 5 parts tetrabutyl titanate in 90 parts anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 h to obtain the precursor gel.

[0066] (2) The precursor gel was injected into a copper mold and frozen in liquid nitrogen for 10 min. Then it was transferred to a vacuum freeze dryer and sublimated and de-iced at -50℃ and 10 Pa for 54 h to obtain zirconium-titanium porous particles.

[0067] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace and heated to 210°C at a rate of 10°C / min for 4 hours. After that, they were naturally cooled to room temperature to obtain modified zirconium-titanium composite particles.

[0068] (4) The modified zirconium-titanium composite particles and α-olefins were mixed evenly in a reaction vessel at a mass ratio of 0.04:1. Hydrogen gas was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, and the reaction was carried out for 10 hours. The mixture was then naturally cooled to room temperature to obtain the base oil.

[0069] (5) Mix 15nm nano-graphene with base oil at a mass ratio of 0.005:1, place in a microwave reactor, and react for 2 minutes at a power of 800W and a frequency of 2.45GHz. Add 10wt% boronized polyisobutylene bis(succinimide), 0.9wt% polymethyl methacrylate, 0.4wt% polyether defoamer, 1wt% magnesium salt detergent, and 30wt% linseed oil, and stir evenly to obtain nano-graphene lubricating oil.

[0070] Example of effect

[0071] Table 1 below presents the performance analysis results of the nano-graphene lubricating oils produced using Examples 1, 2, and 3 of the present invention, and Comparative Examples 1, 2, 3, and 4.

[0072] Table 1

[0073]

[0074] A comparison of the experimental data from Examples 1, 2, and 3 with Comparative Examples 1 and 2 reveals that using modified zirconium-titanium composite particles as a catalyst for the catalytic synthesis of base oil reduces branched and unsaturated structures, increases the thermal decomposition temperature of the base oil, inhibits free radical chain decomposition and fracture, and improves heat resistance. Then, under microwave assistance, graphene is exfoliated while retaining interlayer active carboxyl functional groups, improving the dispersibility of graphene in lubricating oil. Simultaneously, a hydrogen bond network is formed with the surface of the modified zirconium-titanium particles, achieving a bonding effect, reducing fatigue wear, and extending service life. Furthermore, electrochemical deposition occurs between the particles and graphene during friction, repairing microcracks on the metal surface and achieving a self-healing effect. The comparison of the experimental data from Examples 1, 2, and 3 with Comparative Examples 3 and 4 further demonstrates this effect. Comparison of experimental data reveals that by injecting the precursor sol into a pre-cooled liquid nitrogen copper mold, rapidly freezing, and vacuum sublimation drying to remove ice crystals, a snowflake-like hierarchical porous structure is formed, creating a micro-nano-scale micro-oil reservoir. Under frictional heat activation, lubricating molecules are continuously released through capillary action, improving the lubrication effect. Then, low-temperature annealing forms a Zr-O-Ti mixed oxide framework, effectively suppressing pore collapse. Simultaneously, the semiconductor properties of the mixed oxide generate electron cloud shielding at the friction interface, reducing intermetallic adhesion and thus extending service life. Furthermore, through surface hydroxyl groups and capillary action, ionic liquid is adsorbed to form a coating layer, enhancing the dispersion stability of graphene and forming an interfacial double-layer effect, further enhancing the lubrication effect.

[0075] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A nanographene lubricating oil, characterized by, According to weight parts, comprising the following preparation steps: (1) under the atmosphere of nitrogen, the zirconium titanium porous particles are placed in a tube furnace, heated to 180~240℃, and continuously maintained for 2~6h, then naturally cooled to room temperature, immersed in an imidazole ionic liquid, ultrasonicated at 30kHz for 30~50min, the solid is collected by filtration, and dried in a 50℃ oven for 16~24h to obtain modified zirconium titanium composite particles; (2) the modified zirconium titanium composite particles are uniformly mixed with α-olefins in a reaction kettle, hydrogen is introduced to a pressure of 5MPa, heated to 150~210℃, and reacted for 8~12h, then naturally cooled to room temperature to obtain base oil; (3) the nanographene is uniformly mixed with the base oil, placed in a microwave reactor, reacted at a power of 800W and a frequency of 2.45GHz for 1~3min, and then uniformly stirred with 10wt% boronized polyisobutylene bis-succinimide, 0.9wt% polymethacrylate, 0.4wt% polyether antifoaming agent, 1wt% magnesium salt detergent, and 30wt% linseed oil based on the weight of the base oil to obtain nanographene lubricating oil; The preparation steps of the zirconium titanium porous particles are as follows: the precursor gel is injected into a copper mold, frozen in a liquid nitrogen environment for 5~15min, then transferred to a vacuum freeze dryer, and sublimed to remove ice for 48~60h to obtain zirconium titanium porous particles; The imidazole ionic liquid is selected from any one of 1-butyl-3-methylimidazole tetrafluoroborate and 1-ethyl-3-methylimidazole bis-trifluorosulfonimide.

2. The nano-graphene lubricating oil according to claim 1, characterized in that, The preparation steps of the precursor gel are as follows: 5~9 parts of zirconium oxychloride and 4~6 parts of tetrabutyl titanate are dissolved in 90 parts of anhydrous ethanol, the pH is adjusted to 3~4 with 0.5mol / L nitric acid, and stirred at 100rpm for 6~10h to obtain the precursor gel.

3. The nano-graphene lubricating oil according to claim 1, wherein the nano-graphene is dispersed in the base oil in an amount of 0.001 to 0.1% by weight. The parameters of the vacuum freeze dryer are temperature-50℃ and pressure 10Pa.

4. The nano-graphene lubricating oil of claim 1, wherein, The heating rate in step (1) is 10℃ / min.

5. The nano-graphene lubricating oil of claim 1, wherein the nano-graphene lubricating oil has a concentration of 0.1 to 10 wt%. The mass ratio of the modified zirconium titanium composite particles to α-olefins in step (2) is (0.01~0.07):

1.

6. The nano-graphene lubricating oil of claim 1, wherein, The particle size of the nanographene in step (3) is 5~25nm.

7. The nano-graphene lubricating oil of claim 1, wherein the nano-graphene lubricating oil has a viscosity of 1.5 to 2.5 cSt at 40°C. The mass ratio of the nanographene to the base oil in step (3) is (0.001~0.01):1.

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