CN111575086A

CN111575086A - Method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene

Info

Publication number: CN111575086A
Application number: CN202010441966.4A
Authority: CN
Inventors: 曾军堂; 陈庆; 张俊; 陈涛; 司文彬
Original assignee: Chengdu New Keli Chemical Science Co Ltd
Current assignee: Chengdu New Keli Chemical Science Co Ltd
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2020-08-25

Abstract

The invention relates to the technical field of modified lubricating oil, in particular to a method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene, which comprises the following steps: uniformly dispersing graphene, a mixed solvent, a dispersing agent and a foaming agent, adding nano silicon carbide for ultrasonic dispersion, freeze-drying, adding basic lubricating oil for stirring dispersion, heating and grinding, adding an antioxidant, uniformly stirring, and defoaming to obtain the graphene-based lubricating oil. The graphene-based lubricating oil prepared by the preparation method has the advantages of small friction resistance coefficient, high heat conductivity coefficient, high stability and good compatibility, so that the graphene-based lubricating oil has a good protection effect on mechanical parts, and the heat conductivity coefficient is high, so that heat generated in the friction process can be removed in time, and the service life of the mechanical parts is prolonged.

Description

Method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene

Technical Field

The invention relates to the technical field of modified lubricating oil and a preparation method thereof, in particular to a method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene.

Background

The lubricating grease is a lubricating oil which is separated from petroleum and synthesized by hydrogenation, sulfonation, solvent extraction separation method and the like, is mainly used for reducing friction between surfaces of moving parts, and has cooling and sealing functions on machinery and equipment. With the development demand of high-performance equipment, the requirements on precision lubrication such as industrial machinery lubrication, transmission lubrication and the like are higher and higher. When the lubricating grease is used, the working temperature is generally below 200 ℃, polar substances in the lubricating grease are decomposed on the metal surface of a friction part under the action of tribochemical action under high temperature and high load and undergo tribochemical reaction with surface metal to form a soft extreme pressure film with a low melting point and a firm physicochemical adsorption film, so that the lubricating grease has the functions of resisting high load and resisting frictional wear. However, the requirements for high-load and high-speed operation are higher and higher, because the lubricating oil is influenced by temperature, pressure and the like when the friction surface moves, a stable film surface is difficult to form on the friction surface, the friction surface becomes rough under the influence of high bearing capacity, the friction coefficient is increased, the lubricating grease is seriously lost, and 30% of transmission power is lost in the mechanical tradition with poor lubrication, so that the traditional lubricating grease is extremely easy to degrade and lose efficacy in the high-temperature and high-load friction process, and the application limitations of the traditional lubricating grease in the aspects of high bearing capacity, environment friendliness and the like gradually appear.

In order to meet the requirements of high-load anti-wear and anti-friction of lubricating grease, an additive method is generally adopted to improve the lubricating property and the anti-wear property of the lubricating grease. The original used additives are sulfur, phosphorus and chlorine elements, but the pollution is easy to cause, and the effects of anti-wear extreme pressure and anti-friction performance are not ideal. The appearance of the nano material provides a new choice for the development of the lubricating oil additive and attracts people's extensive attention. Two-dimensional layered materials, such as graphene and molybdenum disulfide, are easy to slip under the shearing action and have low friction coefficient, and can form a transfer film on the surface of a friction pair as a lubricating oil additive, so that the abrasion is effectively reduced; the one-dimensional spherical particles, such as diamond, alumina and silicon oxide, can be used as lubricating oil additives to effectively change sliding friction into rolling friction, play the role of a micro bearing and effectively reduce the friction coefficient. Although molybdenum disulfide and graphite are mature to be applied to lubricating oil, the particles are large, so that the lubricating oil is obviously insufficient in the aspect of high-load precision lubrication.

Graphene (Graphene) is a polymer made of carbon atoms in sp²The hybrid tracks form a hexagonal honeycomb lattice two-dimensional carbon nanomaterial. The graphene has excellent optical, electrical and mechanical properties, and has important application prospects in the aspects of materials science, micro-nano processing, energy, biomedicine, drug delivery and the like. The arrangement mode of carbon atoms in the graphene is sp like that of a graphite monoatomic layer²The carbon atom has 4 valence electrons, wherein 3 electrons generate sp bonds, namely each carbon atom contributes one unbound electron on the pz orbit, pz orbitals of adjacent atoms form pi bonds in a direction perpendicular to the plane, and the newly formed pi bonds are in a half-filled state.

Graphene is a nanoscale microchip, due to weak van der waals force between layers, the sheets are easy to slip under the shearing action, the graphene has a low friction coefficient, can be used as an excellent antifriction and wear-resistant material, and can completely meet the requirement of precision lubrication due to the nanoscale, and the nanoscale has a repair function on wear generated by lubrication, so that the graphene is superior to the traditional layered solid lubricating materials such as graphite, molybdenum disulfide and the like in performance. It is obviously difficult to disperse nano-sized graphene in lubricating oil. Conventional graphene below 10 layers is seriously agglomerated, is generally dispersed in a liquid phase manner, and is subjected to coagulation phenomenon; if dispersed in solid form, graphene generally converges to a flocculent form, which is extremely difficult to disperse. If the dispersion does not meet the requirement, the graphene is difficult to achieve the ideal lubricating effect in the lubricating oil.

Disclosure of Invention

In view of the above drawbacks of the prior art, an object of the present invention is to provide a method for preparing a graphene-based lubricating oil by micro-blasting and dispersing graphene, so as to solve the problem that graphene is difficult to achieve an ideal lubricating effect in a lubricating oil in the prior art, and to provide a graphene-based lubricating oil. According to the invention, nano silicon carbide and graphene are used as additives of lubricating oil, the graphene is in a single-atom lamellar structure and is easy to adhere to the surface of nano silicon carbide with larger particles, the nano silicon carbide supports the graphene with smaller particle size and is pre-dispersed in the basic lubricating oil, so that the graphene is effectively prevented from massively agglomerating, then the foaming agent in the graphene system is heated through grinding and heating, so that severe gas expansion is generated, the graphene deposited on the surface of the nano silicon carbide is exploded and dispersed, and the graphene is well dispersed in the basic lubricating oil. The graphene-based lubricating oil prepared by the preparation method has the advantages of small friction resistance coefficient, high heat conductivity coefficient, high stability and good compatibility, the friction coefficient is small, so that a mechanical part is well protected, and the heat generated in the friction process can be timely removed due to the high heat conductivity coefficient, so that the service life of the mechanical part is prolonged.

In order to attain the above and other related objects,

the invention provides a method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene, which comprises the following steps:

step one, mixing the following materials in a mass ratio of (3-15): (50-200): (2-8): (3-15) uniformly dispersing the graphene, the mixed solvent, the dispersing agent and the foaming agent to obtain slurry for later use;

step two, mixing the following materials in a mass ratio of (70-120): (5-50) ultrasonically dispersing the slurry obtained in the step one and the nano silicon carbide, and freeze-drying to obtain dry powder for later use;

step three, mixing the following materials in a mass ratio of (1-5): (80-150) stirring and dispersing the dry powder and the basic lubricating oil in the second step, heating and grinding, adding an antioxidant, uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

The graphene, the mixed solvent, the dispersing agent and the foaming agent are uniformly mixed in advance to form slurry, the graphene is dispersed in the mixed solvent in advance, the graphene can be prevented from being agglomerated in advance, and in addition, the dispersing agent is added to promote the graphene to be dispersed in the mixed solvent. And then the graphene can be deposited on the surface of the nano silicon carbide through ultrasonic dispersion of the slurry and the nano silicon carbide, and the ultrasonic dispersion has the advantages of uniform dispersion and high efficiency. The mixed solvent is removed by freeze drying (recyclable), in which case the properties of the blowing agent are not affected. And mixing the dry powder with the basic lubricating oil, wherein the graphene is deposited on the surface of the nano silicon carbide, so that the graphene cannot be agglomerated in the basic lubricating oil. The heating grinding is used for preventing agglomeration, and grinding and dispersing possibly agglomerated particles; the heating is to foam the foaming agent, and the graphene is dispersed more uniformly in the foaming process; the heating and grinding are processed together, the graphene is dispersed more uniformly, a synergistic effect is achieved, and the processing time can be shortened compared with the case that the graphene is separated from the graphene, so that the preparation efficiency is improved. Finally, defoaming to obtain the finished product. The whole preparation process is relatively simple in process, has low requirements on temperature and pressure, and can be suitable for large-scale production.

Graphene is a nanoscale microchip, due to weak van der waals force between layers, the sheets are easy to slip under the shearing action, the graphene has a low friction coefficient, can be used as an excellent antifriction and wear-resistant material, and can completely meet the requirement of precision lubrication due to the nanoscale, and the nanoscale has a repair function on wear generated by lubrication, so that the graphene is superior to the traditional layered solid lubricating materials such as graphite, molybdenum disulfide and the like in performance. Graphene is one of the materials with the highest known strength, has good toughness and can be bent, the theoretical Young modulus of the graphene reaches 1.0TPa, and the inherent tensile strength is 130 GPa.

The silicon carbide has stable chemical property, high heat conductivity coefficient, small thermal expansion coefficient and good wear resistance.

The silicon carbide and the graphene have a synergistic lubricating effect, a better ball effect is formed, the friction coefficient between friction pairs (the friction pairs are the most important elements for end face sealing) and the abrasion loss of materials can be reduced, and the heat conductivity coefficient and the heat conductivity of the base oil can be obviously improved. The graphene is deposited on the surface of the nano silicon carbide, so that the dispersion performance of the graphene in the basic lubricating oil can be obviously improved, and the thermal conductivity of the graphene-based lubricating oil can be improved due to the fact that the nano silicon carbide has high thermal conductivity. The graphene-based lubricating oil prepared by the preparation method has the advantages of small friction resistance coefficient, high heat conductivity coefficient, high stability and good compatibility, the friction coefficient is small, so that a mechanical part is well protected, and the heat generated in the friction process can be timely removed due to the high heat conductivity coefficient, so that the service life of the mechanical part is prolonged.

As a preferable scheme of the invention: in the first step, the mass ratio of graphene to the mixed solvent to the dispersing agent to the foaming agent is (5-10): (70-140): (3-5): (5-10);

and the mass ratio of the slurry to the nano silicon carbide in the second step is (80-100): (10-30);

in the third step, the mass ratio of the dry powder to the basic lubricating oil is (2-3): (100-120).

According to the graphene-based lubricating oil, the nano silicon carbide and the graphene are used as additives of the lubricating oil, the graphene is in a single-atom lamellar structure and is easy to adhere to the surface of the nano silicon carbide with large particles, the nano silicon carbide bears the graphene with smaller particle size and is pre-dispersed in the basic lubricating oil, so that the graphene is effectively prevented from being agglomerated in a large amount, the foaming agent in a graphene system is heated through grinding and heating, severe gas expansion is generated, the graphene deposited on the surface of the nano silicon carbide is exploded and dispersed, and the graphene is well dispersed in the basic lubricating oil. The silicon carbide and the graphene have a synergistic lubricating effect, a better ball effect is formed, the friction coefficient between friction pairs (the friction pairs are the most important elements for end face sealing) and the abrasion loss of materials can be reduced, and the heat conductivity coefficient and the heat conductivity of the base oil can be obviously improved. The graphene is deposited on the surface of the nano silicon carbide, so that the dispersion performance of the graphene in the basic lubricating oil can be obviously improved, and the thermal conductivity of the graphene-based lubricating oil can be improved due to the fact that the nano silicon carbide has high thermal conductivity. The compatibility among all components can be improved by depositing the graphene on the surface of the nano silicon carbide and adding the dispersing agent, so that the graphene-based lubricating oil can be used as graphene-based lubricating oil to remarkably improve the lubricating state of a friction pair, reduce the friction coefficient among friction materials and the abrasion loss of materials and prolong the service life of a machine.

As a preferable scheme of the invention: in the first step, the mass ratio of the graphene to the mixed solvent to the dispersing agent to the foaming agent is 8: 100: 4: 6;

and in the second step, the mass ratio of the slurry to the nano silicon carbide is 100: 20;

the mass ratio of the dry powder to the basic lubricating oil in the third step is 3: 110.

as a preferable scheme of the invention: in the first step, the mixed solvent is ethanol and deionized water according to a mass ratio of (30-60): (40-80) mixing;

the foaming agent in the first step is at least one of ammonium carbonate and ammonium bicarbonate;

and in the first step, the dispersant is polyisobutylene succinimide.

The graphene falls off from the surface of the nano silicon carbide by heating, foaming and dispersing, and is dispersed in the basic lubricating oil by micro blasting, so that the graphene is dispersed more uniformly in the foaming process. The decomposition temperature of ammonium carbonate and ammonium bicarbonate is low, the requirement on equipment is low, and the performance of the graphene-based lubricating oil cannot be influenced after decomposition.

The polyisobutylene succinimide can not only disperse graphene, but also has better dispersibility and excellent high-temperature stability when being used for lubricating oil. The polyisobutenyl succinimide (T154A) is an ashless dispersant prepared by a thermal addition process by using high-activity polyisobutylene (= 1000) as a raw material, has good cleaning dispersibility, can inhibit the generation of carbon deposit and paint film on an engine piston, and does not contain chlorine.

As a preferable scheme of the invention: the temperature of the dispersion in the first step is 20-40 ℃, the rotating speed is 120-200 rpm, and the dispersion time is 30-60 min.

The graphene, the mixed solvent, the dispersing agent and the foaming agent are uniformly mixed in advance to form slurry, the graphene is dispersed in the mixed solvent in advance, the graphene can be prevented from being agglomerated in advance, and in addition, the dispersing agent is added to promote the graphene to be dispersed in the mixed solvent.

As a preferable scheme of the invention: the ultrasonic frequency of ultrasonic dispersion in the second step is 15 KHz-25 KHz, the ultrasonic temperature is 20 ℃ to 40 ℃, and the ultrasonic time is 15 min-45 min;

and in the second step, the temperature of freeze drying is-40 ℃ to-60 ℃, the absolute pressure is 10Pa to 20Pa, and the drying time is 3h to 5 h.

The slurry and the nano silicon carbide are subjected to ultrasonic dispersion, graphene can be deposited on the surface of the nano silicon carbide, and the ultrasonic dispersion has the advantages of uniform dispersion and high efficiency. The mixed solvent is removed by freeze drying (recyclable), in which case the properties of the blowing agent are not affected.

As a preferable scheme of the invention: the base lubricating oil in the third step is 500N base oil; the antioxidant in the third step is 2, 6-di-tert-butyl-p-cresol.

The selected 500N base oil is suitable for producing medium and high grade lubricating oil, and 2, 6-di-tert-butyl-p-cresol is an oil soluble antioxidant widely used at home and abroad, has strong oxidation resistance, good heat resistance and stability, no peculiar smell, no color reaction when meeting metal ions and the like, and has low price.

As a preferable scheme of the invention: the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol is (900-1100): (5-10).

As a preferable scheme of the invention: stirring speed for stirring and dispersing in the third step is 300-500 rpm, temperature is 20-40 ℃, and time is 15-45 min;

the temperature of the heating and grinding in the third step is 60-90 ℃, the absolute pressure is 0.03-0.05 MPa, and the speed is 10-30 m/min;

the defoaming treatment in the third step specifically comprises the following steps: and (3) defoaming in a centrifugal stirring defoaming machine with the rotating speed of 2000 rmp-2500 rmp for 3-8 min.

The heating grinding is used for preventing agglomeration, and grinding and dispersing possibly agglomerated particles; the heating is to foam the foaming agent, and the graphene is dispersed more uniformly in the foaming process; the heating and grinding are processed together, the graphene is dispersed more uniformly, a synergistic effect is achieved, and the processing time can be shortened compared with the case that the graphene is separated from the graphene, so that the preparation efficiency is improved. Finally, defoaming to obtain the finished product.

According to the graphene-based lubricating oil, the nano silicon carbide and the graphene are used as additives of the lubricating oil, the graphene is in a single-atom lamellar structure and is easy to adhere to the surface of the nano silicon carbide with large particles, the nano silicon carbide bears the graphene with smaller particle size and is pre-dispersed in the basic lubricating oil, so that the graphene is effectively prevented from being agglomerated in a large amount, the foaming agent in a graphene system is heated through grinding and heating, severe gas expansion is generated, the graphene deposited on the surface of the nano silicon carbide is exploded and dispersed, and the graphene is well dispersed in the basic lubricating oil. The silicon carbide and the graphene have a synergistic lubricating effect, a better ball effect is formed, the friction coefficient between friction pairs (the friction pairs are the most important elements for end face sealing) and the abrasion loss of materials can be reduced, and the heat conductivity coefficient and the heat conductivity of the base oil can be obviously improved. The graphene is deposited on the surface of the nano silicon carbide, so that the dispersion performance of the graphene in the basic lubricating oil can be obviously improved, and the thermal conductivity of the graphene-based lubricating oil can be improved due to the fact that the nano silicon carbide has high thermal conductivity. The compatibility among all components can be improved by depositing the graphene on the surface of the nano silicon carbide and adding the dispersing agent, so that the graphene-based lubricating oil can be used as graphene-based lubricating oil to remarkably improve the lubricating state of a friction pair, reduce the friction coefficient among friction materials and the abrasion loss of materials and prolong the service life of a machine. The graphene-based lubricating oil prepared by the preparation method has the advantages of small friction resistance coefficient, high heat conductivity coefficient, high stability and good compatibility, the friction coefficient is small, so that a mechanical part is well protected, and the heat generated in the friction process can be timely removed due to the high heat conductivity coefficient, so that the service life of the mechanical part is prolonged.

As described above, the method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene and the graphene-based lubricating oil provided by the invention have the following beneficial effects:

1. the graphene, the mixed solvent, the dispersing agent and the foaming agent are uniformly mixed in advance to form slurry, the graphene is dispersed in the mixed solvent in advance, the graphene can be prevented from being agglomerated in advance, and in addition, the dispersing agent is added to promote the graphene to be dispersed in the mixed solvent. And then the graphene can be deposited on the surface of the nano silicon carbide through ultrasonic dispersion of the slurry and the nano silicon carbide, and the ultrasonic dispersion has the advantages of uniform dispersion and high efficiency. The mixed solvent is removed by freeze drying (recyclable), in which case the properties of the blowing agent are not affected. And mixing the dry powder with the basic lubricating oil, wherein the graphene is deposited on the surface of the nano silicon carbide, so that the graphene cannot be agglomerated in the basic lubricating oil. The heating grinding is used for preventing agglomeration, and grinding and dispersing possibly agglomerated particles; the heating is to foam the foaming agent, and the graphene is dispersed more uniformly in the foaming process; the heating and grinding are processed together, the graphene is dispersed more uniformly, a synergistic effect is achieved, and the processing time can be shortened compared with the case that the graphene is separated from the graphene, so that the preparation efficiency is improved. Finally, defoaming to obtain the finished product. The whole preparation process is relatively simple in process, has low requirements on temperature and pressure, and can be suitable for large-scale production.

2. Graphene is a nanoscale microchip, due to weak van der waals force between layers, the sheets are easy to slip under the shearing action, the graphene has a low friction coefficient, can be used as an excellent antifriction and wear-resistant material, and can completely meet the requirement of precision lubrication due to the nanoscale, and the nanoscale has a repair function on wear generated by lubrication, so that the graphene is superior to the traditional layered solid lubricating materials such as graphite, molybdenum disulfide and the like in performance. The silicon carbide has stable chemical property, high heat conductivity coefficient, small thermal expansion coefficient and good wear resistance. The silicon carbide and the graphene have a synergistic lubricating effect, a better ball effect is formed, the friction coefficient between friction pairs (the friction pairs are the most important elements for end face sealing) and the abrasion loss of materials can be reduced, and the heat conductivity coefficient and the heat conductivity of the base oil can be obviously improved. The graphene is deposited on the surface of the nano silicon carbide, so that the dispersion performance of the graphene in the basic lubricating oil can be obviously improved, and the thermal conductivity of the graphene-based lubricating oil can be improved due to the fact that the nano silicon carbide has high thermal conductivity. The graphene-based lubricating oil prepared by the preparation method has the advantages of small friction resistance coefficient, high heat conductivity coefficient, high stability and good compatibility, the friction coefficient is small, so that a mechanical part is well protected, and the heat generated in the friction process can be timely removed due to the high heat conductivity coefficient, so that the service life of the mechanical part is prolonged.

Drawings

Fig. 1 shows a flow chart of a method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.

Example 1

A method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene comprises the following steps:

step one, mixing a mixture of 3: 50: 2: 3, uniformly dispersing the graphene, a mixed solvent (formed by mixing ethanol and deionized water according to a mass ratio of 30: 40), a dispersing agent (polyisobutylene succinimide) and a foaming agent (ammonium carbonate) to obtain slurry for later use;

step two, mixing the raw materials in a mass ratio of 70: 8, ultrasonically dispersing the slurry and the nano silicon carbide in the step one, and freeze-drying to obtain dry powder for later use;

step three, mixing the raw materials in a mass ratio of 1: and (5) stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil) in the step two of the step 80, heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

Specifically, the temperature for dispersing in the first step is 20 ℃, the rotating speed is 120 rpm, and the dispersing time is 60 min.

Specifically, the ultrasonic frequency of the ultrasonic dispersion in the second step is 15 KHz, the ultrasonic temperature is 20 ℃, and the ultrasonic time is 45 min; in the second step, the temperature of freeze drying is-40 ℃, the absolute pressure is 10Pa, and the drying time is 5 hours;

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 900: 5; the stirring speed for stirring and dispersing in the third step is 300rpm, the temperature is 40 ℃, and the time is 45 min; the temperature of the heating grinding in the third step is 60 ℃, the absolute pressure is 0.03 MPa, and the speed is 30 m/min; the defoaming treatment in the third step specifically comprises the following steps: defoaming treatment was carried out for 8min in a centrifugal stirring defoaming machine at a rotation speed of 2000 rmp.

Example 2

step one, mixing a mixture of 15: 200: 8: 15, uniformly dispersing graphene, a mixed solvent (formed by mixing ethanol and deionized water according to a mass ratio of 60: 80), a dispersing agent (polyisobutylene succinimide) and a foaming agent (ammonium carbonate) to obtain slurry for later use;

step two, mixing the components in a mass ratio of 120: 45, ultrasonically dispersing the slurry and the nano silicon carbide in the step one, and freeze-drying to obtain dry powder for later use;

step three, mixing the raw materials in a mass ratio of 5: and 150, stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil), heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

Specifically, the temperature for dispersing in the first step is 40 ℃, the rotating speed is 200 rpm, and the dispersing time is 30 min.

Specifically, the ultrasonic frequency of the ultrasonic dispersion in the second step is 25KHz, the ultrasonic temperature is 40 ℃, and the ultrasonic time is 15 min; in the second step, the temperature of freeze drying is-60 ℃, the absolute pressure is 20Pa, and the drying time is 3 h;

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 1100: 10; the stirring speed for stirring and dispersing in the third step is 500rpm, the temperature is 40 ℃, and the time is 15 min; the temperature of the heating grinding in the third step is 90 ℃, the absolute pressure is 0.05 MPa, and the speed is 10 m/min; the defoaming treatment in the third step specifically comprises the following steps: and (3) defoaming in a centrifugal stirring defoaming machine with the rotating speed of 2000 rmp-2500 rmp for 3-8 min.

Example 3

step one, mixing a mixture of 5: 70: 3: 5, uniformly dispersing the graphene, a mixed solvent (formed by mixing ethanol and deionized water according to a mass ratio of 4: 55), a dispersing agent (polyisobutylene succinimide) and a foaming agent (ammonium bicarbonate) to obtain slurry for later use;

step two, mixing the raw materials in a mass ratio of 80: 10, ultrasonically dispersing the slurry and the nano silicon carbide in the step one, and freeze-drying to obtain dry powder for later use;

step three, mixing the raw materials in a mass ratio of 2: and (5) stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil) in the step two of 100, heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

Specifically, the temperature for dispersing in the first step is 30 ℃, the rotating speed is 150rpm, and the dispersing time is 40 min.

Specifically, the ultrasonic frequency of the ultrasonic dispersion in the second step is 18KHz, the ultrasonic temperature is 30 ℃, and the ultrasonic time is 30 min; in the second step, the temperature of freeze drying is-50 ℃, the absolute pressure is 15Pa, and the drying time is 4 hours;

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 1000: 10; the stirring speed of stirring dispersion in the third step is 400rpm, the temperature is 30 ℃, and the time is 30 min; the temperature of the heating grinding in the third step is 70 ℃, the absolute pressure is 0.04MPa, and the speed is 20 m/min; the defoaming treatment in the third step specifically comprises the following steps: the defoaming place was 5min in a centrifugal stirring defoaming machine with a rotation speed of 2200 rmp.

Example 4

step one, mixing the raw materials in a mass ratio of 10: 140: 5: uniformly dispersing 10 parts of graphene, a mixed solvent (formed by mixing ethanol and deionized water according to a mass ratio of 50: 70), a dispersing agent (polyisobutylene succinimide) and a foaming agent (ammonium bicarbonate) to obtain slurry for later use;

step two, mixing the raw materials in a mass ratio of 100: 30, ultrasonically dispersing the slurry and the nano silicon carbide in the step one, and freeze-drying to obtain dry powder for later use;

step three, mixing the raw materials in a mass ratio of 3: and (3) stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil) in the second step of 120, heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

Specifically, the dispersing temperature in the first step is 35 ℃, the rotating speed is 180 rpm, and the dispersing time is 50 min.

Specifically, the ultrasonic frequency of the ultrasonic dispersion in the second step is 22KHz, the ultrasonic temperature is 35 ℃, and the ultrasonic time is 20 min; in the second step, the temperature of freeze drying is-45 ℃, the absolute pressure is 18Pa, and the drying time is 4 hours;

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 994: 6; the stirring speed for stirring and dispersing in the third step is 400rpm, the temperature is 35 ℃, and the time is 25 min; the temperature of the heating grinding in the third step is 70 ℃, the absolute pressure is 0.05 MPa, and the speed is 25 m/min; the defoaming treatment in the third step specifically comprises the following steps: defoaming treatment was carried out for 6min in a centrifugal stirring defoaming machine at a rotation speed of 2300 rmp.

Example 5

step one, mixing 8: 100: 4: 6, uniformly dispersing graphene, a mixed solvent (formed by mixing ethanol and deionized water according to a mass ratio of 40: 60), a dispersing agent (polyisobutylene succinimide) and a foaming agent (ammonium carbonate) to obtain slurry for later use;

step two, mixing the raw materials in a mass ratio of 100: 20, ultrasonically dispersing the slurry and the nano silicon carbide in the step one, and freeze-drying to obtain dry powder for later use;

step three, mixing the raw materials in a mass ratio of 3: and 110, stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil), heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 990: 10; the stirring speed for stirring and dispersing in the third step is 400rpm, the temperature is 35 ℃, and the time is 25 min; the temperature of the heating grinding in the third step is 70 ℃, the absolute pressure is 0.05 MPa, and the speed is 25 m/min; the defoaming treatment in the third step specifically comprises the following steps: defoaming treatment was carried out for 6min in a centrifugal stirring defoaming machine at a rotation speed of 2300 rmp.

Example 6

Specifically, the dispersing temperature in the first step is 40 ℃, the rotating speed is 180 rpm, and the dispersing time is 40 min.

Specifically, the ultrasonic frequency of the ultrasonic dispersion in the second step is 22KHz, the ultrasonic temperature is 30 ℃, and the ultrasonic time is 30 min; in the second step, the temperature of freeze drying is-50 ℃, the absolute pressure is 10Pa, and the drying time is 4 hours;

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 992: 8; the stirring speed for stirring and dispersing in the third step is 400rpm, the temperature is 30 ℃, and the time is 30 min; the temperature of the heating grinding in the third step is 60 ℃, the absolute pressure is 0.04MPa, and the speed is 20 m/min; the defoaming treatment in the third step specifically comprises the following steps: defoaming treatment was carried out for 5min in a centrifugal stirring defoaming machine at a rotation speed of 2300 rmp.

Comparative example 1

step one, mixing 8: 100: 4, uniformly dispersing the graphene, a mixed solvent (formed by mixing ethanol and deionized water according to a mass ratio of 40: 60) and a dispersing agent (polyisobutylene succinimide) to obtain slurry for later use;

step three, mixing the raw materials in a mass ratio of 3: and 110, stirring and dispersing the dry powder and the base lubricating oil (500N base oil), heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), and uniformly stirring to obtain the graphene-based lubricating oil.

The graphene-based lubricating oil is prepared by the preparation method.

Compared with example 6, the comparative example 1 has no foaming agent added, so that a micro-explosion foaming link is avoided, and the dispersion effect is poor.

Comparative example 2

step two, performing ultrasonic dispersion on the slurry obtained in the step one, and freeze-drying to obtain dry powder for later use;

step three, setting the mass ratio to be 2.4 (the content of graphene is similar to that of the graphene in the embodiment 6): and 110, stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil), heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

Comparative example 2 did not have the addition of nano-silicon carbide compared to example 6.

Comparative example 3

step three, mixing the raw materials in a mass ratio of 3: and 110, stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil), adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

specifically, the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol in the third step is 992: 8; the stirring speed for stirring and dispersing in the third step is 400rpm, the temperature is 30 ℃, and the time is 30 min; the defoaming treatment in the third step specifically comprises the following steps: defoaming treatment was carried out for 5min in a centrifugal stirring defoaming machine at a rotation speed of 2300 rmp.

Comparative example 3 does not conduct the micro-explosion foaming by means of heat grinding, so that the foaming efficiency of the foaming agent is lowered, compared to example 6.

Comparative example 4

step three, mixing the components in a mass ratio of 0.5: and (5) stirring and dispersing the dry powder and the basic lubricating oil (500N basic oil) in the step two of 100, heating and grinding, adding an antioxidant (2, 6-di-tert-butyl-p-cresol), uniformly stirring, and defoaming to obtain the graphene-based lubricating oil.

Comparative example 4 the dry powder and the base lubricant (500N base oil) were added in different amounts in comparative example 4 compared to example 6.

The following tests were performed on the graphene-based lubricating oils prepared in examples 1 to 6 and comparative examples 1 to 4, and the test results are shown in table 1:

measuring the average friction coefficient of the graphene-based lubricating oil and the 500N base oil in the example 1-6 and the comparative example 1-4 under the test conditions of 300N load, 30min time and 1450r/min rotation speed;

determining the amount of precipitates of the graphene-based lubricating oil and the 500N base oil in examples 1 to 6 and comparative examples 1 to 4 after centrifugation at 5000rpm for 30 min;

the wear resistance of the graphene-based lubricating oils of examples 1 to 6 and comparative examples 1 to 4 was measured.

The abrasion resistance of the product is tested by referring to a four-ball method for testing the bearing capacity of GB/T3142-2019 lubricant: the abrasion resistance under the load (the temperature is 20 ℃, the load is 294N, the speed is 1200R/min, and the time is 30 min) is set by utilizing the four-ball machine for measurement, and steel balls used in the four-ball test are CCr15 standard steel balls with the diameter of 12.7 mm. PB represents the maximum non-seizure load, i.e., the maximum load at which seizure does not occur under specified conditions when the extreme pressure performance of the lubricant is measured by the four-ball method, and is expressed in newtons (or kg). Sometimes referred to as maximum oil film strength. The PD value is the minimum load in newtons (or kg) under which the sintering of a rotating ball with three stationary balls occurs under the test conditions. As shown in table 1.

Table 1:

as can be seen from table 1: compared with example 6, in comparative example 1, no foaming agent is added, so that a micro-blasting foaming link is avoided, the dispersion effect is poor, and the performance of graphene is affected. Therefore, the average friction coefficient and the wear scar diameter of the graphene-based lubricating oil in comparative example 1 are large, and thus it can be seen that the performance improvement of the 500N base oil is inferior to those of examples 1 to 6.

Comparative example 2 did not have the addition of nano-silicon carbide compared to example 6. The nano silicon carbide is used as a carrier on one hand and is used as an additive for improving the thermal conductivity of 500N base oil on the other hand. In comparative example 2, no nano silicon carbide is added, so that graphene cannot be deposited on the surface of the nano silicon carbide, and partial agglomeration can occur, so that trace precipitation occurs, and the stability of the graphene-based lubricating oil is affected. In addition, the thermal conductivity of the graphene-based lubricating oil in comparative example 2 was also low.

Comparative example 3 does not conduct the micro-explosion foaming by means of heat grinding, so that the foaming efficiency of the foaming agent is lowered, compared to example 6. The performance of comparative example 3 is slightly better than comparative example 1 due to the addition of the blowing agent in comparative example 3. However, since the graphene is not completely separated from the surface of the nano silicon carbide by the heat grinding micro-blasting, the performance of the graphene is affected, and the finally prepared graphene-based lubricating oil has a friction resistance (average friction coefficient) and a heat conductivity which are lower than those of example 6.

Comparative example 4 the dry powder and the base lubricant (500N base oil) were added in different amounts in comparative example 4 compared to example 6. Since the addition amount of the dry powder is small in comparative example 4 (equivalent to the addition amount of the graphene and the nano silicon carbide is reduced at the same time), the heat conduction performance and the friction resistance of the graphene-based lubricating oil are affected.

On the whole, by testing the graphene-based lubricating oil prepared in the embodiments 1 to 6, graphene is uniformly dispersed in the basic lubricating oil, and the graphene has a two-dimensional nano-layered structure, so that the performance of the lubricating oil is remarkably improved in the aspect of wear resistance, and the lubricating effect is enhanced.

In conclusion, the graphene-based lubricating oil prepared by the preparation method has the advantages of small friction resistance coefficient, high heat conductivity coefficient, high stability and good compatibility, so that the graphene-based lubricating oil has a good protection effect on mechanical parts due to the small friction coefficient, and the heat generated in the friction process can be removed in time due to the high heat conductivity coefficient, so that the service life of the mechanical parts is prolonged. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A method for preparing graphene-based lubricating oil by micro-blasting dispersed graphene is characterized by comprising the following steps:

2. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 1, wherein the method comprises the following steps:

in the first step, the mass ratio of graphene to the mixed solvent to the dispersing agent to the foaming agent is (5-10): (70-140): (3-5): (5-10);

3. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 2, wherein the method comprises the following steps:

in the first step, the mass ratio of the graphene to the mixed solvent to the dispersing agent to the foaming agent is 8: 100: 4: 6;

4. the method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 1, wherein the method comprises the following steps:

in the first step, the mixed solvent is ethanol and deionized water according to a mass ratio of (30-60): (40-80) mixing;

and in the first step, the dispersant is polyisobutylene succinimide.

5. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 1, wherein the method comprises the following steps: the temperature of the dispersion in the first step is 20-40 ℃, the rotating speed is 120-200 rpm, and the dispersion time is 30-60 min.

6. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 1, wherein the method comprises the following steps:

the ultrasonic frequency of ultrasonic dispersion in the second step is 15 KHz-25 KHz, the ultrasonic temperature is 20 ℃ to 40 ℃, and the ultrasonic time is 15 min-45 min;

7. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 1, wherein the method comprises the following steps: the base lubricating oil in the third step is 500N base oil; the antioxidant in the third step is 2, 6-di-tert-butyl-p-cresol.

8. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to claim 7, wherein the method comprises the following steps: the mass ratio of the 500N base oil to the 2, 6-di-tert-butyl-p-cresol is (900-1100): (5-10).

9. The method for preparing the graphene-based lubricating oil from the micro-blasting dispersed graphene according to any one of claims 1 to 3, wherein the method comprises the following steps:

stirring speed for stirring and dispersing in the third step is 300-500 rpm, temperature is 20-40 ℃, and time is 15-45 min;