Preparation method of high-temperature-resistant heavy-load organic-inorganic multi-element hybrid nano lubricant
By loading multi-component nanoparticles on the graphene surface to form a multi-component hybrid nanolubricant, the problems of decomposition, corrosion and poor dispersion of traditional lubricating additives in high temperature and heavy load environments are solved, and the lubrication performance is significantly improved.
Patent Information
- Application Number
- CN202510923399.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-04
- Publication Date
- 2025-10-17
AI Technical Summary
Traditional lubricating additives are prone to decomposition, strong corrosiveness or ash generation under harsh environments such as high temperature and heavy load, leading to friction and wear problems. Graphene has poor dispersion stability in lubricating oil, which affects lubrication performance.
By loading multiple nanoparticles on the graphene surface, including transition metal oxides, loaded calcium-based lubricating components and single transition metal oxide-polyorganic compound nanospheres, a multi-component hybrid nanolubricant is formed. The anchoring effect and steric hindrance of the nanoparticles are utilized to enhance the dispersibility and interface stability.
Significantly reduces friction coefficient and wear rate under high temperature and heavy load conditions, improves lubrication performance, and achieves green and environmentally friendly lubrication effects.
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Figure CN120795977A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of materials, lubrication and tribology, and particularly relates to a preparation method of a high-temperature-resistant heavy-load organic-inorganic multi-component hybrid nano-lubricant. BACKGROUND
[0002] With the continuous progress of mechanical engineering technology, the working environment of mechanical equipment becomes more and more complex, especially in extreme working conditions such as high temperature, high load, high speed or corrosion, the lubrication system faces higher requirements. Friction and wear problems not only directly affect the service life and energy efficiency of equipment, but also can cause serious mechanical failure. Therefore, lubricating oil and grease as the key lubricating medium play a crucial role in reducing friction and wear and improving equipment reliability, and lubricating additives as the core factor for improving the performance of lubricating oil have become the focus of research.
[0003] Traditional lubricating additives have many limitations in harsh environments such as high temperature and heavy load. For example, some traditional additives are prone to decomposition in high temperature environment, producing toxic gases; some additives have strong corrosiveness to the friction interface; and others are prone to generate ash, causing catalyst poisoning and other problems. These defects significantly limit the application of traditional lubricating additives in high-performance lubrication systems. Therefore, developing a green, efficient and stable lubricating additive has become an important research direction in the current lubrication field.
[0004] Graphene is widely recognized as a new type of lubricating additive with great potential due to its unique two-dimensional layered structure, high mechanical strength, excellent chemical stability and self-lubricating performance. Compared with traditional additives, graphene can significantly reduce the friction coefficient and wear rate, and meet the trend of low sulfur, low phosphorus and green sustainable development. However, due to the large specific surface area and strong van der Waals force of graphene, it is prone to agglomeration and sedimentation in lubricating oil, resulting in poor dispersion stability and affecting the lubrication performance.
[0005] In order to improve the dispersion stability of graphene in lubricating oil, researchers have proposed the concept of graphene nanocomposite lubricating additives. By loading nanoparticles on the surface of graphene, the anchoring effect and steric hindrance of nanoparticles are used to inhibit the agglomeration of particles and improve the dispersion of graphene in base oil. In addition, the loaded nanoparticles can also enhance the interaction between the lubricating additive and the friction interface, improve the stability of the film, and optimize the lubrication performance.
[0006] Although graphene nanocomposite lubricating additives have excellent performance in improving lubricating properties, current research on them under extreme working conditions is still limited. Under harsh conditions such as high temperature and high load, the stability of the adsorbed film is poor, which easily leads to lubrication failure. Therefore, how to regulate the nanoparticles loaded on the graphene sheet to form a two-dimensional composite structure with multiple nanoparticles synergistic effect to enhance the interfacial adsorption capacity and film stability has become the key to improving the lubricating properties under extreme working conditions. SUMMARY
[0007] To solve the above problems, the application provides a preparation method of a high-temperature-resistant and heavy-load organic-inorganic multi-component hybrid nanometer lubricant. The application is dedicated to developing a graphene nanocomposite additive with simple preparation process, strong controllability and applicability to multi-component organic-inorganic nanoparticles loading. The technology can not only effectively improve the dispersibility of graphene in lubricating oil, but also enhance the stability of the lubricating interface under extreme working conditions such as high temperature and high load, and has important research value and broad application prospect.
[0008] One of the technical solutions provided by the application is:
[0009] A multifunctional nanocomposite additive includes graphene and active nanoparticles loaded on the surface and interlayer of the graphene sheet; the active nanoparticles include one or more of transition metal oxide composite nanoparticles, calcium-based lubricating components, single transition metal oxide-polyorganic compound nanospheres and modified oxides.
[0010] Further, the transition metal in the transition metal oxide composite nanoparticles is selected from two or more of manganese, copper, silver, iron and zinc; the single transition metal oxide-polyorganic compound nanosphere includes single transition metal oxide and polyorganic compound nanosphere, and the organic compound in the polyorganic compound nanosphere is dopamine or tetraethyl orthosilicate.
[0011] The second technical solution provided by the application is:
[0012] A preparation method of the above multifunctional nanocomposite additive, when the active nanoparticles are transition metal oxide composite nanoparticles, includes the following steps: under ice water bath, transition metal soluble salt and flake graphite are placed in concentrated sulfuric acid, stirred and reacted, then the water bath temperature is increased to 40 DEG C and kept for 1 h, second stirring and reaction is carried out, the mixed system is obtained, hydrogen peroxide is added after dilution of the mixed system, three times of reaction is carried out, the pH of the mixed system is adjusted to 12, centrifugation, washing, filtration and drying are carried out after heat treatment, and ball milling is carried out to obtain the multifunctional nanocomposite additive.
[0013] Further, the transition metal soluble salt is selected from two of potassium permanganate, manganese chloride, copper chloride, silver nitrate and ferric sulfate; and / or, the temperature of the heat treatment is 150-450℃, preferably, the temperature of the heat treatment is 180℃.
[0014] Further, the transition metal soluble salt is selected from two of potassium permanganate, manganese chloride, copper chloride, silver nitrate and ferric sulfate; and / or, the temperature of the heat treatment is 150-450℃, preferably, the temperature of the heat treatment is 180℃.
[0015] A preparation method of the multifunctional nanocomposite additive, when the active nanoparticles are calcium-based lubricating components, a soluble calcium salt solution and a sodium carbonate solution are added to a graphene oxide solution, stirred and reacted, filtered, the obtained filter cake is heat treated, washed, dried, and CaCO 3- A graphene composite is obtained, a surface modifier is added to the CaCO 3- The graphene composite is ground until the surface modifier disappears completely, the obtained solid is ball milled and sieved to obtain the multifunctional nanocomposite additive.
[0016] Further, the volume ratio of the graphene oxide solution, the soluble calcium salt solution and the sodium carbonate solution is 25:5:6; the concentration of the graphene oxide solution is 2.0-5.0wt.%, the concentration of the soluble calcium salt solution and the sodium carbonate solution is 1mol / L; the mass ratio of the CaCO 3- The graphene composite and the surface modifier is (2-10):1, preferably 10:1; and / or, the temperature of the heat treatment is 150-450℃, preferably, the temperature of the heat treatment is 180℃.
[0017] A preparation method of the multifunctional nanocomposite additive, when the active nanoparticles are single transition metal oxide-polyorganic compound nanospheres and modified oxides, includes the following steps: under ice water bath, flake graphite and potassium permanganate are added to concentrated sulfuric acid, stirred and reacted, the water bath temperature is increased to 40℃ and kept for 1h, stirred and reacted twice, a mixed system is obtained, the mixed system is diluted and hydrogen peroxide is added, reacted three times, the pH of the mixed system is adjusted to neutral, hydrochloric acid dopamine solution or tetraethyl orthosilicate solution is added to the mixed system, ammonia water is added, the pH is adjusted, stirred and reacted four times, heat treated again, centrifuged, washed, filtered, dried, and ball milled to obtain the multifunctional nanocomposite additive.
[0018] Further, the volume ratio of the graphene oxide solution, the soluble calcium salt solution and the sodium carbonate solution is 25:5:6; the concentration of the graphene oxide solution is 2.0-5.0wt.%, the concentration of the soluble calcium salt solution and the sodium carbonate solution is 1mol / L; the mass ratio of the CaCO 3- The graphene composite and the surface modifier is (2-10):1, preferably 10:1; and / or, the temperature of the heat treatment is 150-450℃, preferably, the temperature of the heat treatment is 180℃.
[0019] Further, the mass ratio of dopamine hydrochloride to graphene is (2-6) : 1, and the mass ratio of tetraethyl orthosilicate to graphene is (2-6) : 1.
[0020] The third technical solution of the present application provides:
[0021] A high-temperature-resistant heavy-load organic-inorganic multi-component hybrid nanometer lubricant is prepared by adding the multifunctional nanometer composite additive into lubricating oil.
[0022] The lubricating oil includes base oil, ester lubricating oil, bio-based lubricating oil, commercial lubricating grease, rapeseed oil and special lubricating oil, wherein the special lubricating oil refers to lubricating oil applied in low-temperature or high-temperature environment.
[0023] The adding concentration of the multifunctional nanometer composite additive is 0.05-3 wt.%, preferably 1 wt.% by mass of the lubricating oil, which can strengthen oil film stability by graphene structure, improve lubricating wear resistance, and reduce friction coefficient and energy loss.
[0024] Compared with the prior art, the present application has the following advantages and technical effects:
[0025] (1) The present application can load different kinds of nanoparticles on graphene by adjusting the type of salt solution, realize the synthesis of multi-component loaded particles, and thus simply and conveniently synthesize high-temperature-resistant heavy-load organic-inorganic multi-component hybrid nanometer lubricant.
[0026] (2) If the loaded particles contain transition metal ions, the transition metal ions in the original graphene oxide solution can be used to realize green in-situ preparation of nanometer composite additive, achieving high efficiency and environmental protection.
[0027] (3) The modification of the loaded particles by organic acid can increase the dispersion performance of the nanometer composite additive in lubricating oil.
[0028] (4) The high-temperature-resistant heavy-load organic-inorganic multi-component hybrid nanometer lubricant prepared by the present application has excellent lubricating and wear-reducing performance under extreme working conditions. BRIEF DESCRIPTION OF DRAWINGS
[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0030] Figure 1 The preparation flow chart of the multifunctional nanometer composite additive in the present application is shown in the figure.
[0031] Figure 2 TEM micrograph of Mn-Fe-0 / G prepared for Example 1;
[0032] Figure 3 Friction coefficient curves for base oil, multi-manganese iron loaded particles / graphene + base oil, and trimanganese tetroxide / graphene + base oil;
[0033] Figure 4 Wear track depth plots for base oil and multi-manganese iron loaded particles / graphene + base oil under heavy load (2.2 GPa).
[0034] Figure 5 Friction coefficient curves for base oil, calcium carbonate, calcium oleate / graphene + base oil, and calcium carbonate / graphene + base oil;
[0035] Figure 6 Wear track depth plots for base oil and calcium carbonate, calcium oleate / graphene + base oil under heavy load (2.2 GPa). DETAILED DESCRIPTION
[0036] Various illustrative embodiments of the present application are described in detail below. The detailed description is presented in terms of specific embodiments which include particular components, materials, and dimensions. Those skilled in the art will recognize that the application can be practiced with
[0037] It should be understood that the terms used herein are for the purpose of describing particular embodiments and are not intended to limit the application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value by each intervening value, as well as any other stated or intervening value in that stated range is encompassed. The upper and lower limits of these intervening values can independently be included or excluded in the range, and the endpoints are reserved for their specifically stated values. Unless in context, none of the above terms imply that any particular range of values is excluded. It should also be understood that, unless clearly indicated to the contrary, where a parameter range is provided, it is to be understood that all intervening values, to the extent they do not adversely affect the desired characteristics, are included in the range.
[0038] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference to the extent allowed by law. In the case of conflict between the descriptions in the specification and those in the incorporated literature, the present specification will control.
[0039] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application in any way.
[0040] As used herein, "comprise", "comprising", "having", "including", "contain", "containing", "include" and the like are open-ended terms that are intended to mean including, but not limited to.
[0041] The embodiment of the present application provides a preparation method of a multifunctional nano composite additive, so as to improve tribological properties under extreme working conditions by loading multiple nanoparticles, and comprises the following steps:
[0042] (1) Preparation of graphene oxide original solution: if the transition metal ions are contained in the loaded particles, the required salt solution is directly added into the graphene oxide original solution, then stirring is carried out, and heat treatment is carried out, so as to complete the synthesis of the loaded particles and the reduction of graphene oxide; if there is no transition metal ion, the graphene oxide original solution is subjected to suction filtration, washing, dispersion, addition of the required salt solution and sufficient stirring and heat treatment, so as to complete the synthesis of the loaded particles and the reduction of graphene oxide, and different types of nanoparticles can be loaded on graphene by only adjusting the type of added metal salt, so as to realize the synthesis of multiple loaded particles;
[0043] (2) The solid obtained in step (1) is washed and dried to obtain a multiple graphene nano composite additive. If the dispersibility is to be improved, the dried solid can be mixed with an organic acid and ground in a mortar until the organic acid disappears, so as to realize the modification of the loaded particles by the organic acid.
[0044] Figure 1 The preparation flow chart of the multifunctional nano composite additive in the present application is shown in the figure.
[0045] The flake graphite used in the embodiment of the present application is purchased from Alfa Aesar Chemical Co., Ltd.; the concentration of the concentrated sulfuric acid used is 98 wt.%, and the concentration of the hydrogen peroxide used is 30 wt.%; the ferric sulfate, sodium carbonate and potassium hydroxide used are all analytical pure and are purchased from the National Pharmaceutical Group Chemical Reagent Co., Ltd.; the dopamine hydrochloride used is purchased from Macklin Biochemical Technology Co., Ltd.; and the base oil in the embodiment of the present application is poly-alpha olefin synthetic oil PAO6, which is purchased from Jinzhou Baiter Chemical Co., Ltd.
[0046] Example 1
[0047] (1) Graphite oxidation and Mn 2+ and Fe 3+ Interlayer: under an ice water bath (≤5℃), 5g of flake graphite, 20g of potassium permanganate and 25g of ferric sulfate are slowly added into 150mL of concentrated sulfuric acid in sequence, and stirring is carried out for 5min; the water bath temperature is increased to 40℃ and kept for 1h, and the stirring is continuously carried out during the period, so as to form a suspension liquid and obtain a mixed system; then 500mL of deionized water is added into the mixed system for dilution, and then 25mL of hydrogen peroxide is slowly added dropwise, so as to ensure that MnO4 2+ is completely converted into Mn2+ The addition of hydrogen peroxide changes the color of the suspension from dark brown to golden yellow, and while achieving graphite oxidation, it also makes Mn 2+ and Fe 3+ Adsorbed on the surface and interlayer of graphene oxide sheets;
[0048] (2) Synthesis of MnFe2O4 and Mn3O4 nanoparticles and reduction of graphene oxide: Slowly add potassium hydroxide solution (5M) to the suspension obtained in step (1) and stir for 5 minutes until the pH value of the mixed system reaches 12; heat treat the mixed system at 180°C for 5 hours to reduce the graphene oxide to graphene. After the above reaction, the Mn loaded on the surface and between the graphene sheets is reduced. 2+ and Fe 3+ It has been completely converted into MnFe2O4 and Mn3O4 nanoparticles and centrifuged to obtain graphene loaded with MnFe2O4 and Mn3O4 nanoparticles;
[0049] (3) Post-treatment: The graphene loaded with MnFe2O4 and Mn3O4 nanoparticles obtained in step (2) was added to 500 mL of deionized water, stirred for 30 min, and the pH value of the suspension was measured and filtered. The above washing operation was repeated four times until the pH value of the solution was measured to be 8. Impurities such as potassium hydroxide and other soluble salts adsorbed on the surface of the graphene can be washed off by repeated washing. The filter cake was placed in a forced air drying oven (80°C, 2 h), and the dried solid was ball milled (200 r / min, 5 h). After the ball milling, it was sieved through a 200-mesh sieve to obtain a solid powder, which is a multifunctional nanocomposite additive with a small particle size (20 μm) and a relatively uniform distribution, recorded as Mn-Fe-O / G (i.e., multi-element manganese iron loaded particles / graphene).
[0050] Figure 2 This is a TEM scanning electron microscope image of Mn-Fe-O / G prepared in Example 1. Figure 2 It can be seen that the particles are evenly loaded on the graphene sheet without obvious defects, and are mainly rectangular and spherical in shape.
[0051] Comparative Example 1
[0052] The same as Example 1, except that ferric sulfate was not added in step (1), and the prepared nanolubricant was recorded as Mn3O4 / G (i.e., manganese tetraoxide / graphene).
[0053] 1 wt.% of Mn-Fe-O / G and Mn3O4 / G, respectively, based on the weight of base oil, to obtain multi-element manganese iron loaded particles / graphene + base oil and Mn3O4 / graphene + base oil, and the base oil and the multi-element manganese iron loaded particles / graphene + base oil and the Mn3O4 / graphene + base oil are respectively subjected to heavy load condition testing, the testing method being that ball-on-disc friction and wear testing is carried out at room temperature using a UMT friction and wear tester under a load of 2.2 GPa and a speed of 2.4 mm / s.
[0054] The test results show that the friction coefficient of the multi-element manganese iron loaded particles / graphene + base oil is reduced by 23% compared with the base oil under heavy load conditions (2.2 GPa), and the wear rate is reduced by 72.5% compared with the base oil, and the friction coefficient of the Mn3O4 / graphene + base oil is reduced by 14% compared with the base oil under heavy load conditions (2.2 GPa), and the wear rate is reduced by 46% compared with the base oil. It can be seen that the high-temperature resistant heavy load organic-inorganic multi-element hybrid nano lubricant (multi-element manganese iron loaded particles / graphene + base oil) prepared by the present application exhibits excellent lubricating and wear-reducing performance under heavy load. Figure 3 The friction coefficient curves of the base oil, the multi-element manganese iron loaded particles / graphene + base oil and the Mn3O4 / graphene + base oil can be seen from Figure 3 , and it can be seen that the multi-element manganese iron loaded particles / graphene + base oil can significantly reduce the friction coefficient.
[0055] Figure 4 The wear scar depth diagrams of the base oil and the multi-element manganese iron loaded particles / graphene + base oil under heavy load (2.2 GPa) can be seen from Figure 4 , and it can be seen that the multi-element manganese iron loaded particles / graphene prepared by Example 1 can significantly reduce wear.
[0056] Example 2
[0057] (1) Graphite oxidation treatment: 5 g of flake graphite and 20 g of potassium permanganate are slowly added to 150 mL of concentrated sulfuric acid under an ice water bath (≤ 5℃), and stirred for 5 min; the water bath temperature is increased to 40℃, and kept for 1 h with constant stirring to form a suspension, to obtain a mixed system; 500 mL of deionized water is added to the mixed system for dilution, and then 25 mL of hydrogen peroxide is slowly added dropwise, to ensure that MnO4 2+ is completely converted to Mn 2+ , and the addition of hydrogen peroxide changes the color of the suspension from dark brown to golden yellow, which realizes the oxidation of graphite and also makes Mn 2+ adsorbed on the surface and between the layers of graphene oxide, the obtained suspension is suction filtered, and then washed with 500 mL of dilute hydrochloric acid (35 wt.%) and 500 mL of deionized water for 4 times and filtered, to completely remove the Mn 2+The filter cake was re-dispersed in 500 mL of deionized water to obtain a graphene oxide solution;
[0058] (2) Synthesis of CaCO3-loaded and reduction of graphene oxide: 100 mL of calcium chloride solution (1 M) and 120 mL of sodium carbonate solution (1 M) were slowly added to the graphene oxide solution obtained in step (1) in sequence, and stirred for 15 min to allow the synthesized CaCO3 particles to be loaded on the surface of graphene oxide. The filter cake was heat-treated at 180 ℃ for 5 h to reduce the graphene oxide to graphene to obtain CaCO3 / G.
[0059] (3) Post-treatment: The solid after heat treatment in step (2) was added to 500 mL of deionized water and washed for 4 times to remove the soluble salts adsorbed on the surface of graphene. The filter cake was dried in a blast drying oven (80 ℃, 2 h), and then 8.9 g of the dried solid was ground with 1 mL of oleic acid in a mortar until the oleic acid completely disappeared to modify the CaCO3 / G. The modified solid was ball-milled (200 r / min, 5 h), and the solid powder obtained after sieving through a 200-mesh sieve was a multifunctional nano-composite additive with small particle size (15 μm) and uniform distribution, which was recorded as CaCO3-OA / G (i.e., calcium carbonate, calcium oleate / graphene).
[0060] Comparative Example 2
[0061] The same as in Example 2, except that step (3) post-treatment was not performed, and the nano-lubricant prepared was recorded as CaCO3 / G (i.e., calcium carbonate / graphene).
[0062] 1 wt.% of CaCO3-OA / G and CaCO3 / G, respectively, based on the weight of the base oil, to obtain calcium carbonate, calcium oleate / graphene + base oil and calcium carbonate / graphene + base oil, and perform heavy load condition test, and the test method is the same as in Example 1.
[0063] The test results show that under the heavy load condition (2.2 GPa), the friction coefficient of calcium carbonate, calcium oleate / graphene + base oil (high-temperature and heavy-load resistant organic-inorganic multi-component hybrid nano-lubricant) is reduced by 37.9% compared with that of the base oil, and the wear rate is reduced by 65.7% compared with that of the base oil, the friction coefficient of calcium carbonate / graphene + base oil is reduced by 21% compared with that of the base oil, and the wear rate is reduced by 34% compared with that of the base oil, which proves that the high-temperature and heavy-load resistant organic-inorganic multi-component hybrid nano-lubricant prepared by the present application exhibits excellent lubricating and wear-reducing performance under heavy load.
[0064] Figure 5 The friction coefficient curves of the base oil, calcium carbonate, calcium oleate / graphene + base oil and calcium carbonate / graphene + base oil are shown in FIG. 2. Figure 5It can be seen from the above that CaC03-OA / G prepared in Example 2 can significantly reduce the friction coefficient.
[0065] Figure 6 The wear scar depth diagram of base oil and calcium carbonate, calcium oleate / graphene + base oil under heavy load (2.2 GPa) is shown in FIG. 4. Figure 6 It can be seen from the above that CaC03-OA / G prepared in Example 2 can significantly reduce the friction coefficient.
[0066] Example 3:
[0067] (1) Graphite oxidation: Under an ice water bath (≤ 5°C), 5 g of flake graphite and 20 g of potassium permanganate were slowly added to 150 mL of concentrated sulfuric acid in sequence, and stirred for 5 min; the water bath temperature was raised to 40°C and maintained for 1 h, during which the suspension was continuously stirred, to form a mixed system; 500 mL of deionized water was added to the mixed system for dilution, and then 25 mL of hydrogen peroxide was slowly added dropwise, to ensure that Mn04 2+ was completely converted to Mn 2+ The addition of hydrogen peroxide changed the color of the suspension from dark brown to golden yellow, which achieved the oxidation of graphite and also made Mn 2+ adsorbed on the surface and between the layers of graphene oxide; then potassium hydroxide solution (50 wt.%) was added to the suspension to adjust the pH of the solution to 7;
[0068] (2) Synthesis of polydopamine nanospheres and manganese trioxide nanoparticles and reduction of graphene oxide: 125 mL of anhydrous ethanol and 250 mL of deionized water were mixed, 25 g of dopamine hydrochloride solid was added to the mixed solution to obtain a dopamine hydrochloride solution, and the dopamine hydrochloride solution (100 mL) and ammonia water (5 mL) with a concentration of 25 wt.% were added to the suspension obtained in step (1), and the pH of the solution was adjusted to 9, and the solution was magnetically stirred for 24 h. Dopamine hydrochloride self-polymerizes on the surface of graphene to form polydopamine, and manganese ions react to form manganese hydroxide; the mixed system was heat-treated at 180°C for 5 h to reduce the graphene oxide to graphene, and the manganese hydroxide to manganese trioxide attached to the surface of the graphene;
[0069] (3) Post-processing: The solid after heat treatment in step (2) was added to 500 mL of deionized water and washed 4 times to remove the soluble salts adsorbed on the surface of the graphene, filtered, and the obtained filter cake was dried in a blast drying oven (80°C, 2 h), and the dried solid was ball milled (200 r / min, 5 h). After ball milling, it was sieved through a 200-mesh sieve to obtain a solid powder, which was an organic-inorganic multi-component hybrid nanolubricant with small particle size (20 μm) and uniform distribution, and was denoted as DA-Mn-O / G.
[0070] Comparative Example 3
[0071] The same as example 3, except that no polydopamine was loaded, only manganese trioxide was loaded, and the specific preparation method was the same as that of comparative example 1, which was denoted as Mn3O4 / G.
[0072] 1wt.% of DA-Mn-O / G and Mn3O4 / G was added respectively based on the weight of the base oil to obtain DA-Mn-O / G modified base oil and Mn3O4 / G modified base oil, and the base oil, DA-Mn-O / G modified base oil and DA / G modified base oil were subjected to heavy load test, and the test method was the same as that of example 1.
[0073] The test results show that the average friction coefficient of the base oil is 0.174, the average friction coefficient of the DA-Mn-O / G modified base oil is 0.116, which is reduced by 33.3% compared with the friction coefficient of the base oil, and the average friction coefficient of the Mn3O4 / G modified base oil is 0.150, which is reduced by 14% compared with the friction coefficient of the base oil.
[0074] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A multifunctional nanocomposite additive, characterized in that: The invention comprises graphene and active nanoparticles loaded on the surface and between the graphene sheets; the active nanoparticles comprise one or more of transition metal oxide composite nanoparticles, loaded calcium-based lubricating components, single transition metal oxide-polyorganic compound nanospheres and modified oxides.
2. The multifunctional nanocomposite additive according to claim 1, characterized in that The transition metal in the transition metal oxide composite nanoparticles is selected from two or more of manganese, copper, silver, iron and zinc; the single transition metal oxide-polyorganic compound nanospheres include a single transition metal oxide and polyorganic compound nanospheres, and the organic compound in the polyorganic compound nanospheres is dopamine or tetraethyl orthosilicate.
3. A method for preparing the multifunctional nanocomposite additive according to claim 1 or 2, characterized in that: When the active nanoparticles are transition metal oxide composite nanoparticles, the preparation method comprises the following steps: placing a transition metal soluble salt and flake graphite in concentrated sulfuric acid in an ice-water bath, stirring and reacting, then raising the water bath temperature to 40°C and maintaining it for 1 hour, stirring and reacting a second time to obtain a mixed system, diluting the mixed system and adding hydrogen peroxide, reacting a third time, adjusting the pH of the mixed system to 12, centrifuging after heat treatment, washing, filtering, drying, and ball milling to obtain the multifunctional nanocomposite additive.
4. The preparation method according to claim 3, characterized in that The transition metal soluble salt is selected from two of potassium permanganate, manganese chloride, copper chloride, silver nitrate and ferric sulfate; and / or the heat treatment temperature is 150-450°C.
5. The preparation method according to claim 4, characterized in that The soluble transition metal salts are potassium permanganate and ferric sulfate, and the usage ratio of the flake graphite, potassium permanganate, ferric sulfate and concentrated sulfuric acid is 1g:4g:5g:30mL.
6. A method for preparing the multifunctional nanocomposite additive according to claim 1 or 2, characterized in that: When the active nanoparticles are loaded calcium-based lubricating components, a soluble calcium salt solution and a sodium carbonate solution are added to a graphene oxide solution, the reaction is stirred, and the filter is filtered. The resulting filter cake is heat-treated, washed, and dried to obtain a CaCO3-graphene composite. A surface modifier is added to the CaCO3-graphene composite, and the composite is ground until the surface modifier completely disappears. The resulting solid is ball-milled and sieved to obtain the multifunctional nanocomposite additive.
7. The preparation method according to claim 6, characterized in that The volume ratio of the graphene oxide solution, the soluble calcium salt solution and the sodium carbonate solution is 25:5:6; the concentrations of the soluble calcium salt solution and the sodium carbonate solution are both 1 mol / L; the mass ratio of the CaCO3-graphene composite and the surface modifier is (2-10):1; and / or the temperature of the heat treatment is 150-450°C.
8. A method for preparing the multifunctional nanocomposite additive according to claim 1 or 2, characterized in that: When the active nanoparticles are single transition metal oxide-polyorganic compound nanospheres, the method comprises the following steps: adding flake graphite and potassium permanganate to concentrated sulfuric acid in an ice-water bath, stirring for reaction, raising the water bath temperature to 40°C and maintaining for 1 hour, stirring for reaction a second time to obtain a mixed system, diluting the mixed system and adding hydrogen peroxide, reacting a third time, adjusting the pH value of the mixed system to neutral, adding dopamine hydrochloride solution or tetraethyl orthosilicate solution to the mixed system, then adding ammonia water, adjusting the pH value, stirring for reaction a fourth time, heat treatment, centrifugation, washing, filtering, drying, and ball milling to obtain the multifunctional nanocomposite additive.
9. The preparation method according to claim 8, characterized in that The usage ratio of the flake graphite, potassium permanganate and concentrated sulfuric acid is 1 g:4 g:30 mL; and / or the temperature of the heat treatment is 150-450° C.
10. A high temperature resistant and heavy load organic-inorganic multi-component hybrid nano-lubricant, characterized in that: The multifunctional nanocomposite additive according to claim 1 or 2 is added to lubricating oil to prepare the product.