Preparation method and application of nickel-iron layered double hydroxide / molybdenum disulfide composite nano material

Abstract

The invention relates to a preparation method and application of a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial, NiFe-LDH and molybdenum disulfide (MoS2) are compounded to prepare an oil-soluble NiFe-LDH-MoS2 composite nanomaterial, and the oil-soluble NiFe-LDH-MoS2 composite nanomaterial combines the electrochemical activity of NiFe-LDH and the low friction characteristic of MoS2 so as to obtain more excellent lubricating performance. Meanwhile, the lubricating oil additive shows excellent friction reduction and wear resistance under high-temperature and high-pressure conditions, and the stability of a friction workpiece in an extreme environment can be improved. When being used as a novel lubricating oil additive, the additive can effectively improve the antifriction and antiwear properties of lubricating grease, improve the bearing capacity of a friction pair and prolong the service life of equipment. The prepared oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nano material can be well dispersed in base oil. As a lubricating oil additive, the tribological performance of lubricating oil can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of novel functional nanomaterials, in particular to a preparation method of a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial and application thereof. Background Art

[0002] In modern industry, friction and wear are often the main causes of equipment performance degradation and energy waste, especially in various mechanical systems and equipment. Whether it is a small nanoelectromechanical system (NEMS) or a large-scale integrated electric propulsion system such as an aircraft carrier, the reliability and energy efficiency of these systems are limited by tribological problems. The contact surfaces of the friction pair experience a large contact pressure during operation, which leads to increased friction, wear and energy loss, and may even cause mechanical failure. Therefore, finding efficient lubricants and friction-reducing additives has always been a research focus in the fields of engineering technology and materials science.

[0003] As an important component of mechanical equipment, lubricating oil directly affects the service life and operating efficiency of the equipment. Studies have shown that adding appropriate lubricating additives can significantly improve the tribological properties of lubricating oil, reduce friction and wear, and extend the service life of equipment. As one of the core components of lubricating oil, the performance and mechanism research of anti-wear and friction reducers has always been the key in the field of lubricating oil. Existing anti-wear and friction reducers are mainly small molecular organic matter, such as zinc dialkyl dithiophosphate (ZDDP), but these traditional additives have disadvantages such as poor thermal stability, limited operating temperature, and easy failure, especially under high temperature and high load conditions. This limits their application in high-end equipment and becomes a bottleneck affecting the development of my country's high-end equipment manufacturing industry.

[0004] As the application of nanomaterials in the field of tribology gradually increases, research has found that nanomaterials as lubricant additives can effectively control friction and wear behavior, especially under extreme working conditions, and can exert their excellent lubrication performance. Nanoparticles have a high surface area, good thermal and chemical stability, and can form a self-repairing lubricating film on the friction contact surface, reducing wear and improving the operating efficiency of the equipment.

[0005] Layered double hydroxide (LDH), as a material with a unique crystal structure, shows significant application potential in the field of tribology. The layered structure and adjustable interlayer spacing of LDH materials give them unique advantages in lubrication. In particular, nickel-iron layered double hydroxide (NiFe-LDH) has an electrochemical activity that makes it particularly outstanding in lubricating oils. At the same time, molybdenum disulfide (MoS2) is often used to enhance friction materials due to its excellent lubrication properties, especially its low friction characteristics under high load conditions. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial and its application, which has low energy consumption, low cost, mild reaction conditions, is suitable for large-scale industrial production and application, is more stable when used under high temperature conditions, and the magnetic nanoparticles can be recovered by applying a magnetic field, thereby reducing pollution to the environment.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial, comprising the following steps: Step S1, adding ammonium tetrathiomolybdate, a precursor of molybdenum disulfide nanoparticles, to a surface modifier and an organic solvent, mixing them evenly, stirring, and reacting at a constant temperature of 350-360° C. in an inert gas atmosphere with stirring for 60-80 minutes; Step S2, when the temperature drops to 50-100° C., metal chloride, polyol, alkaline substance and surface modifier are added one by one, and the reaction is continued under inert gas atmosphere at 180-190° C. for 30-40 minutes with stirring; Step S3, after the reaction is completed, the mixture is subjected to solid-liquid separation and washing to obtain an oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial; Wherein, in step S1, the precursor ammonium tetrathiomolybdate is synthesized from molybdenum trioxide and ammonium sulfide.

[0008] As a further improvement of the present invention: the precursor ammonium tetrathiomolybdate is synthesized from molybdenum trioxide and ammonium sulfide in a ratio of 1g:20-40ml. Preferably, the ratio used is 1g:20ml.

[0009] As a further improvement of the present invention: 10-15 ml of surface modifier can be added to every 0.15 g of ammonium tetrathiomolybdate, and 15-20 ml of organic solvent can be added to every 0.15 g of ammonium tetrathiomolybdate.

[0010] As a further improvement of the present invention: the organic solvent is octadecene or the like; the surface modifier is oleylamine or the like; the selected polyol is ethylene glycol or the like; the selected alkaline substance is sodium hydroxide or the like.

[0011] As a further improvement of the present invention: in the step S1, the surface modifier is oleylamine.

[0012] As a further improvement of the present invention: in the step S1, the organic solvent is octadecene.

[0013] As a further improvement of the present invention: in the step S2, the metal chloride is composed of a mixture of ferrous chloride tetrahydrate and nickel chloride hexahydrate in a mass ratio of 1:1, and the addition ratio of the metal chloride to the surface modifier is 0.1g:10-20ml.

[0014] As a further improvement of the present invention: in the step S2, the alkaline substance is sodium hydroxide, and the addition ratio of the alkaline substance to the polyol is 0.1-0.3 g: 20-30 ml.

[0015] As a further improvement of the present invention: in the step S2, the polyol selected is ethylene glycol, and the addition ratio of the metal chloride to the polyol is 0.1 g: 20-30 ml.

[0016] As a further improvement of the present invention: in step S3, the washing detergent is anhydrous ethanol.

[0017] As a further improvement of the present invention: a method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: 1) Add ammonium tetrathiomolybdate, oleylamine and octadecene into a three-necked flask and stir thoroughly overnight to obtain a mixed solution; 2) Pass argon gas into the mixed solution to exhaust the air in the bottle; 3) Heat the mixed solution to 350-360°C and stir at constant temperature for 60-80 minutes; 4) When the temperature drops to 50-100°C, add ferrous chloride tetrahydrate and nickel chloride hexahydrate, ethylene glycol, sodium hydroxide and oleylamine one by one, and continue to stir and react at 180-190°C under an inert gas atmosphere for 30-40 minutes; 5) After the reaction is completed, a black paste is obtained by repeated centrifugation and washing; 6) Drying in a vacuum drying oven at 60-70° C. for 10-12 hours to obtain black solid particles, which are oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials.

[0018] The present invention also includes a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared according to the above-mentioned method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial.

[0019] The present invention also includes the use of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared according to the above-mentioned nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial preparation method in lubricating oil additives or anti-wear and friction reducers.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts the composite method of NiFe-LDH and MoS2, combining the advantages of both. NiFe-LDH has strong electrochemical activity, and MoS2 plays a role in the friction pair with its low friction characteristics. The composite nanomaterial is used as a lubricating additive for polyalphaolefin (PAO). The composite strategy combines the electrochemical activity of NiFe-LDH and the low friction characteristics of MoS2 to obtain better lubrication performance, which can significantly reduce the friction coefficient and wear. Especially under high temperature and high load conditions, it shows extremely excellent anti-wear and friction reduction effects, which is far superior to traditional lubricating additives such as zinc dialkyl dithiophosphate (ZDDP).

[0021] Compared with the existing preparation method of oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials, the present invention has the advantages of low energy consumption, low cost, mild reaction conditions, etc. The reaction process is simple and safe, and does not require complex equipment or expensive reagents, and is suitable for large-scale industrial production. This improvement provides a feasible economic basis for large-scale application, can effectively reduce production costs, and improve production efficiency.

[0022] The oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial of the present invention has good magnetic properties and can be recovered by an external magnetic field, greatly reducing the impact on the environment. At the same time, the material can be well dispersed in the base oil, avoiding the phenomenon of precipitation and uneven dispersion, and further improving its effect in practical applications.

[0023] The oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared by the present invention can be used as a lubricating oil additive to significantly improve the tribological properties of the lubricating oil, especially showing great advantages in friction reduction and anti-wear. Compared with traditional additives, the friction coefficient and wear spot diameter are significantly reduced, thereby effectively improving the load-bearing capacity of the friction pair and extending the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution, the drawings required for use in the implementation will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 is a Tyndall effect diagram of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in Example 1 dissolved in n-hexane; Figure 2 This is an optical picture of the static precipitation experiment of Example 1. The results show that under room temperature conditions, the dried nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial is well dispersed when added to the base oil; Figure 3 is the XRD pattern of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in Example 1; Figure 4 TEM images of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in Example 1 dissolved in anhydrous ethanol at different sizes (50 nm, 5 nm); Figure 5 The infrared spectra of oleylamine and oleylamine-modified nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials; Figure 6 This is a comparison chart of the friction coefficient of the base oil PAO6 of Example 1 and the base oil PAO6 + 1.0wt% of nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 75°C, 392N, 1200r / min); Figure 7 The wear spot image (a) of the base oil PAO6 of Example 1 and the wear spot image (b) of the base oil PAO6 + 1.0wt% of nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 75°C, 392N, 1200r / min); Figure 8 This is a comparison chart of the friction coefficient of the base oil PAO6 of Example 1 and the base oil PAO6 + 1.0wt% of nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 100°C, 392N, 1200r / min); Fig. 9 The wear spot image (a) of the base oil PAO6 of Example 1 and the wear spot image (b) of the base oil PAO6 + 1.0wt% of nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 100°C, 392N, 1200r / min); Fig.10 This is a comparison chart of the friction coefficient of the base oil PAO6 of Example 1 and the base oil PAO6 + 1.0wt% of nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 150°C, 392N, 1200r / min); Fig.11 The wear spot image (a) of the base oil PAO6 of Example 1 and the wear spot image (b) of the base oil PAO6 + 1.0wt% of nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 150°C, 392N, 1200r / min). DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] Friction and wear are the main reasons for equipment performance degradation and energy waste in modern industry. Especially under high load and extreme working conditions, the contact surface of the friction pair is subjected to greater pressure, resulting in increased friction, aggravated wear and possible mechanical failure. Therefore, the development of efficient lubricants and anti-friction additives has become a research focus in engineering technology and materials science. Traditional anti-wear and anti-friction agents, such as zinc dialkyl dithiophosphate (ZDDP), have problems such as poor thermal stability and easy failure under high temperature and high load conditions, which limits their application in high-end equipment. With the increasing application of nanomaterials in the field of tribology, nanoparticles have shown excellent performance in lubrication due to their excellent thermal stability, chemical stability and self-healing ability. Layered double hydroxides (LDH), especially nickel-iron layered double hydroxides (NiFe-LDH), and molybdenum disulfide (MoS2), as lubricant additives, have shown good anti-friction and anti-wear effects under extreme working conditions due to their electrochemical activity and low friction characteristics, and have important application potential.

[0029] The present invention combines the electrochemical activity of NiFe-LDH with the low friction performance of MoS2 to form an oil-soluble NiFe-LDH-MoS2 nanomaterial through compounding. As a lubricating oil additive, the composite material can effectively improve the tribological properties of the lubricating oil, improve the lubricity of the friction pair, reduce wear, and thus extend the service life of the equipment. However, the current preparation method of the oil-soluble NiFe-LDH-MoS2 composite nanomaterial is usually more complicated and has a high production cost, which limits its large-scale industrial application.

[0030] Therefore, the present invention proposes a method for preparing an oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial synthesized by a one-pot method. The method not only has the advantages of low energy consumption and low cost, but also has mild reaction conditions, is suitable for large-scale production, and has strong application prospects. The promotion of this technology will help reduce the production cost of lubricating materials, improve the development efficiency of high-performance lubricating oils, and provide a new solution for improving the tribological performance of high-end equipment.

[0031] The present invention is further described with reference to the accompanying drawings and embodiments: A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: Step S1, adding ammonium tetrathiomolybdate, a precursor of molybdenum disulfide nanoparticles, to a surface modifier and an organic solvent, mixing them evenly, stirring, and reacting them at a constant temperature of 350-360° C. in an inert gas atmosphere for 60-80 minutes; the precursor ammonium tetrathiomolybdate is synthesized from molybdenum trioxide and ammonium sulfide; Step S2, when the temperature drops to 50-100° C., metal chloride, polyol, alkaline substance and surface modifier are added one by one, and the reaction is continued under inert gas atmosphere at 180-190° C. for 30-40 minutes with stirring; Step S3, after the reaction is completed, the mixture is subjected to solid-liquid separation and washing to obtain an oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial; A nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared according to the above method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial; The nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared according to the above nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial preparation method is used in lubricating oil additives or anti-wear and friction reducing agents.

[0032] The present invention is further described below using specific embodiments: Example

[0033] A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: 1) Add 0.15 g of ammonium tetrathiomolybdate, 15 ml of oleylamine and 15 ml of octadecene into a 100 ml three-necked flask, and stir thoroughly overnight to obtain a mixed solution; 2) Pass argon gas into the mixed solution to exhaust the air in the bottle; 3) The mixed solution was heated to 350°C and stirred at constant temperature for 60 minutes; 4) When the temperature drops to 100°C, add 0.1g of ferrous chloride tetrahydrate and 0.1g of nickel chloride hexahydrate, 20ml of ethylene glycol, 0.1g of sodium hydroxide and 20ml of oleylamine one by one, and continue to stir and react at 190°C for 30min under an inert gas atmosphere; 5) After the reaction is completed, a black paste is obtained by repeated centrifugation and washing; 6) Drying in a vacuum drying oven at 60° C. for 12 h to obtain black solid particles, which are oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials. Example

[0034] A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: 1) Add 0.16 g of ammonium tetrathiomolybdate, 11 ml of oleylamine and 16 ml of octadecene into a 100 ml three-necked flask, and stir thoroughly overnight to obtain a mixed solution; 2) Pass argon gas into the mixed solution to exhaust the air in the bottle; 3) The mixed solution was heated to 350°C and stirred at constant temperature for 60 minutes; 4) When the temperature drops to 50°C, add 0.1g of ferrous chloride tetrahydrate and 0.1g of nickel chloride hexahydrate, 20ml of ethylene glycol, 0.1g of sodium hydroxide and 10ml of oleylamine one by one, and continue to stir and react at 190°C for 30min under an inert gas atmosphere; 5) After the reaction is completed, a black paste is obtained by repeated centrifugation and washing; 6) Drying in a vacuum drying oven at 60° C. for 12 h to obtain black solid particles, which are oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials. Example

[0035] A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: 1) Add 0.15 g of ammonium tetrathiomolybdate, 20 ml of oleylamine and 20 ml of octadecene into a 100 ml three-necked flask, and stir thoroughly overnight to obtain a mixed solution; 2) Pass argon gas into the mixed solution to exhaust the air in the bottle; 3) The mixed solution was heated to 350°C and stirred at constant temperature for 60 minutes; 4) When the temperature drops to 100°C, add 0.1g of ferrous chloride tetrahydrate and 0.1g of nickel chloride hexahydrate, 20ml of ethylene glycol, 0.1g of sodium hydroxide and 10ml of oleylamine one by one, and continue to stir and react at 190°C for 30min under an inert gas atmosphere; 5) After the reaction is completed, a black paste is obtained by repeated centrifugation and washing; 6) Drying in a vacuum drying oven at 60° C. for 12 h to obtain black solid particles, which are oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials. Example

[0036] A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: 1) Add 0.15 g of ammonium tetrathiomolybdate, 15 ml of oleylamine and 15 ml of octadecene into a 100 ml three-necked flask, and stir thoroughly overnight to obtain a mixed solution; 2) Pass argon gas into the mixed solution to exhaust the air in the bottle; 3) The mixed solution was heated to 350°C and stirred at constant temperature for 60 minutes; 4) When the temperature drops to 100°C, add 0.15g of ferrous chloride tetrahydrate and 0.15g of nickel chloride hexahydrate, 20ml of ethylene glycol, 0.15g of sodium hydroxide and 10ml of oleylamine one by one, and continue to stir and react at 190°C under an inert gas atmosphere for 30 minutes; 5) After the reaction is completed, a black paste is obtained by repeated centrifugation and washing; 6) Drying in a vacuum drying oven at 60° C. for 12 h to obtain black solid particles, which are oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials. Example

[0037] A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial comprises the following steps: 1) Add 0.15 g of ammonium tetrathiomolybdate, 15 ml of oleylamine and 15 ml of octadecene into a 100 ml three-necked flask, and stir thoroughly overnight to obtain a mixed solution; 2) Pass argon gas into the mixed solution to exhaust the air in the bottle; 3) The mixed solution was heated to 360°C and stirred at constant temperature for 70 minutes; 4) When the temperature drops to 100°C, add 0.1g of ferrous chloride tetrahydrate and 0.1g of nickel chloride hexahydrate, 20ml of ethylene glycol, 0.1g of sodium hydroxide and 10ml of oleylamine one by one, and continue to stir and react at 190°C for 30min under an inert gas atmosphere; 5) After the reaction is completed, a black paste is obtained by repeated centrifugation and washing; 6) Drying in a vacuum drying oven at 60° C. for 12 h to obtain black solid particles, which are oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials.

[0038] Comparative Example: Referring to Example 1, the polyol was replaced by triethanolamine as a surface modifier from ethylene glycol. After the reaction was completed, the black liquid was centrifuged and no product was obtained. Moreover, no substance was separated after acetone was added to the solution and centrifuged, and the corresponding composite nanomaterial could not be prepared.

[0039] The nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in Example 1 was tested, and the results are as follows: like Figure 1 As shown, the Tyndall effect diagram of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in Example 1 dissolved in n-hexane; the figure proves that the synthesized nickel-iron layered double hydroxide / molybdenum disulfide composite material is nanometer level.

[0040] Through the Tyndall effect and optical microscope observation, the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial of the present invention maintains good dispersibility in oil, making the stability of the material in lubricating oil more superior than that of traditional materials, avoiding the degradation of lubrication performance caused by precipitation and separation.

[0041] like Figure 2 As shown in the optical picture of the static precipitation experiment of Example 1, the results show that under room temperature conditions, the dried nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial is well dispersed when added to the base oil and presents a black suspension. The PAO6 lubricating oil containing 1.0wt% oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial maintains good dispersion stability at room temperature for 20 days. A black flocculent precipitate is produced on the 30th day.

[0042] As shown in Figure 3, the oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in this embodiment was characterized by X-ray diffraction (XRD). It can be seen from the figure that the diffraction peaks at 12.8°, 33.0°, 34.1°, 38.4°, 41.1°, 48.1°, 58.7°, and 60.5° can correspond to the (003), (101), (012), (104), (015), (107), (110), and (113) planes of MoS2 (JCPDS Card No. 17-0744). The diffraction peaks at 11.2°, 33.5°, 34.4°, 38.9°, 59.9°, and 61.3° can correspond to the (003), (101), (012), (015), (110), and (113) planes of NiFe-LDH (JCPDS card number 40-0215). The appearance of these characteristic peaks indicates that the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial has been successfully prepared in the present invention. The crystal structure and high dispersibility of NiFe-LDH and MoS2 are clearly demonstrated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), which provides theoretical support for the self-healing ability of the material in lubricating oil and further improves the stability of the composite nanomaterial under extreme working conditions.

[0043] like Figure 4 As shown, the TEM image of the oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared in Example 1 dissolved in anhydrous ethanol; it can be seen from the figure that the synthesized nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial is measured using Digital Micrograph software Figure 4 The lattice spacings of the (107) and (015) planes of MoS2 and NiFe-LDH are shown to be 0.19 nm and 0.21 nm, respectively.

[0044] like Figure 5 As shown in Example 1, the infrared spectra of oleylamine and oleylamine-modified nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials. -CH3 and -CH2 are located at 2924 cm −1 and 2842cm −1 At 720cm −1 At least 4 methyl groups -(CH2) appear in the region n- The methylene swing vibration. As shown by the dotted line in the figure, the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial has the above characteristic peaks of oleylamine. The deformation vibration peak and bending vibration peak of the NH bond appear at 1462cm −1 and 800cm −1 The position of oleylamine-modified nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterials is 1462 cm −1The peak at 800 cm-1 shifts to the right. −1 The peak at also disappears, as shown in the figure. This may be due to the physical adsorption of oleylamine on the surface of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial through coordination. Therefore, it can be inferred that the surface of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial is successfully modified by oleylamine, thereby preventing its aggregation and improving its compatibility with the lubricating base oil.

[0045] like Figure 6 As shown, a comparison chart of the friction coefficient of the base oil PAO6 in Example 1 and the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 75°C, 392N, 1200r / min); it can be seen from the figure: the average friction coefficient of the base oil PAO6 is 0.122, the average friction coefficient of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 0.066, and the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 45.90% lower than the average friction coefficient of the PAO6 base oil, and the friction reduction performance is relatively excellent.

[0046] like Figure 7 As shown, the wear spot diagram (a) of the base oil PAO6 of Example 1 and the wear spot diagram (b) of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 75°C, 392N, 1200r / min); it can be seen from the figure: the average wear spot diameter of the base oil PAO6 is 0.667mm, the average wear spot diameter of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 0.573mm, and the average wear spot diameter of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is reduced by 14.09% compared with the average wear spot diameter of the PAO6 base oil, and the anti-wear performance is excellent.

[0047] like Figure 8 As shown, a comparison chart of the friction coefficient of the base oil PAO6 of Example 1 and the base oil PAO6+1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 100°C, 392N, 1200r / min); it can be seen from the figure: the average friction coefficient of the base oil PAO6 is 0.095, the average friction coefficient of the base oil PAO6+1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 0.068, and the base oil PAO6+1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 28.42% lower than the average friction coefficient of the PAO6 base oil, and the friction reduction performance is relatively excellent.

[0048] like Fig. 9 As shown, the wear spot diagram (a) of the base oil PAO6 of Example 1 and the wear spot diagram (b) of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 100°C, 392N, 1200r / min); it can be seen from the figure: the average wear spot diameter of the base oil PAO6 is 0.637mm, the average wear spot diameter of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 0.589mm, and the average wear spot diameter of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 7.54% lower than that of the PAO6 base oil.

[0049] like Fig.10 As shown, a comparison chart of the friction coefficient of the base oil PAO6 in Example 1 and the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 150°C, 392N, 1200r / min); it can be seen from the figure: the average friction coefficient of the base oil PAO6 is 0.109, the average friction coefficient of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 0.102, and the average friction coefficient of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 6.42% lower than that of the PAO6 base oil.

[0050] like Fig.11 As shown, the wear spot diagram (a) of the base oil PAO6 of Example 1 and the wear spot diagram (b) of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive; (experimental conditions: 150°C, 392N, 1200r / min); it can be seen from the figure: the average wear spot diameter of the base oil PAO6 is 0.829mm, the average wear spot diameter of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 0.650mm, and the average wear spot diameter of the base oil PAO6 + 1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive is 21.59% lower than that of the PAO6 base oil, and the anti-wear performance is excellent.

[0051] The experimental results of the friction coefficient show that compared with the base oil PAO6, after adding 1.0wt% oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial, the friction coefficient is reduced by 45.90% (at 75°C). This performance shows that the composite material of the present invention has a strong friction reduction effect, can effectively reduce friction loss under high temperature and high pressure, and significantly improve the operating efficiency of the equipment.

[0052] Wear spot experiments show that under different temperature conditions (75°C, 100°C, 150°C), lubricating oil with the composite material can effectively reduce the diameter of wear spots, and its anti-wear performance is significantly better than that of base oil, especially at 150°C, where the diameter of wear spots is reduced by 21.59%. This result proves that the material of the present invention can still maintain excellent anti-wear performance under high temperature and high load, thus extending the service life of the equipment.

[0053] The material can still maintain good dispersibility and lubricity in high temperature environments, and can also be recovered through magnetic fields to reduce the impact on the environment, meeting the requirements of sustainable development.

[0054] Depend on Figure 1 , Figure 3 and Figure 4 It can be seen that the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial was successfully prepared. Figure 6-11 The friction coefficient and wear spot diameter of base oil PAO6+1.0wt% nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial additive at different temperatures were compared and analyzed, and it showed the best anti-wear and friction reduction performance at 75℃.

[0055] As the temperature rises, the composite material still shows a significant friction reduction effect compared to the base oil PAO6. Even at a high temperature of 150°C, the friction coefficient is still 6.42% lower than the base oil, and the wear spot diameter is reduced by 21.59%, proving that the material can maintain excellent lubrication at high temperatures.

[0056] The nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared by the invention can be used as a lubricating oil additive and can significantly improve the tribological properties of the lubricating oil at 75°C, showing a lower friction coefficient and a smaller wear spot diameter.

[0057] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical scheme and technical concept of the present invention without creative mental work, which all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial, characterized in that: The following steps are involved: Step S1, adding ammonium tetrathiomolybdate, a precursor of molybdenum disulfide nanoparticles, to a surface modifier and an organic solvent, mixing them evenly, stirring, and reacting at a constant temperature of 350-360° C. in an inert gas atmosphere with stirring for 60-80 minutes; Step S2, when the temperature drops to 50-100° C., metal chloride, polyol, alkaline substance and surface modifier are added one by one, and the reaction is continued under inert gas atmosphere at 180-190° C. for 30-40 minutes with stirring; Step S3, after the reaction is completed, the mixture is subjected to solid-liquid separation and washing to obtain an oil-soluble nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial; Wherein, in step S1, the precursor ammonium tetrathiomolybdate is synthesized from molybdenum trioxide and ammonium sulfide.

2. The method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 1, characterized in that: The precursor ammonium tetrathiomolybdate is synthesized from molybdenum trioxide and ammonium sulfide in a ratio of 1g:20-40ml.

3. A method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 2, characterized in that: In the step S1, the surface modifier is oleylamine.

4. The method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 3, characterized in that: In the step S1, the organic solvent is octadecene.

5. The method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 1, characterized in that: In the step S2, the metal chloride is composed of a mixture of ferrous chloride tetrahydrate and nickel chloride hexahydrate in a mass ratio of 1:1, and the addition ratio of the metal chloride to the surface modifier is 0.1 g: 10-20 ml.

6. The method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 5, characterized in that: In the step S2, the alkaline substance is sodium hydroxide, and the addition ratio of the alkaline substance to the polyol is 0.1-0.3 g: 20-30 ml.

7. The method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 6, characterized in that: In the step S2, the selected polyol is ethylene glycol, and the addition ratio of the metal chloride to the polyol is 0.1 g: 20-30 ml.

8. The method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to claim 1, characterized in that: In step S3, the washing agent is anhydrous ethanol.

9. A nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared according to the method for preparing a nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to any one of claims 1 to 8.

10. Application of the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial prepared by the method for preparing the nickel-iron layered double hydroxide / molybdenum disulfide composite nanomaterial according to any one of claims 1 to 8 in lubricating oil additives or anti-wear and friction reducing agents.

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