Lubricant composition containing hydroxyl-rich nanoparticles, preparation method and application

Abstract

The invention discloses a lubricant composition containing hydroxyl-rich nano-particles as well as a preparation method and application of the lubricant composition. The lubricant composition comprises the hydroxyl-rich nano-particles, a sorbitan fatty acid ester compound and an oily base solution, the hydroxyl-rich nano-particles are selected from at least one of silicon dioxide nano-particles, aluminum oxide nano-particles and titanium dioxide nano-particles. The preparation method of the lubricant composition comprises the following steps: mixing the sorbitan fatty acid ester compound with the oily base liquid according to a certain proportion; after heating and stirring, adding hydroxyl-rich nano-particles, continuing heating and stirring, standing and cooling to obtain the lubricant composition; the lubricant composition can also be used for preparing a friction protection film with the thickness of 50-600nm on the iron-based metal surface, and the film can reduce the friction coefficient and protect the matrix.

Description

Technical Field

[0001] The present invention belongs to the field of lubrication technology and surface treatment technology, and particularly relates to a lubricant composition containing hydroxyl-rich nanoparticles, a preparation method and an application thereof. Background Art

[0002] Friction and wear are widely present in the operation of mechanical equipment and are one of the key issues affecting the working efficiency and service life of mechanical equipment. Current industrial lubricants are generally based on base oil, and functional additives are added to improve their wear resistance, friction reduction and antioxidant properties. Among them, commonly used additives often contain elements such as sulfur and phosphorus, which can undergo tribochemical reactions with metal surfaces under high loads to form phosphate or sulfide protective films, thereby reducing friction and wear. However, this process is essentially a lubrication mechanism that relies on the continuous consumption of additives. It not only shortens the service life of the lubricant, but may also affect the stable operation of the equipment due to fluctuations in lubrication performance.

[0003] Nanoparticles exhibit interfacial and size effects, making them useful as functional components in lubricating systems to improve the friction reduction and wear resistance of lubricants. However, due to strong van der Waals interactions between particles, agglomeration and sedimentation often occur, making it difficult to evenly disperse nanoparticles in lubricants, thus limiting their performance in practical applications. Summary of the Invention

[0004] In order to solve the problem that existing nanoparticles are prone to agglomeration and sedimentation, which makes them difficult to disperse evenly in lubricants, the present invention provides a lubricant composition containing hydroxyl-rich nanoparticles, a preparation method and an application. The lubricant composition provided by the present invention is in a gel state at room temperature and has excellent lubricating properties, and the nanoparticles can be evenly dispersed in the lubricant and can be maintained for a long time. In addition. The lubricant composition can also be used to prepare friction protection films. Under the action of friction, heating and load, the lubricant composition containing hydroxyl-rich nanoparticles can form a friction protection film with uniform composition and dense structure on the metal surface, which can effectively protect the friction interface and improve the friction reduction and wear resistance of the friction pair.

[0005] According to a first aspect of the present invention, there is provided a lubricant composition containing hydroxyl-rich nanoparticles, the lubricant composition comprising hydroxyl-rich nanoparticles, a sorbitan fatty acid ester compound, and an oily base fluid;

[0006] The hydroxyl-rich nanoparticles are nanoparticles with a high density of hydroxyl groups on the surface, stable chemical properties and low density;

[0007] The hydroxyl-rich nanoparticles are selected from at least one of silicon dioxide nanoparticles, aluminum oxide nanoparticles, and titanium dioxide nanoparticles;

[0008] Optionally, the particle size of the hydroxyl-rich nanoparticles is 20 to 50 nm.

[0009] The sorbitan fatty acid ester compound is selected from at least one of sorbitan monostearate, sorbitan monooleate, and sorbitan tristearate.

[0010] Optionally, the mass fraction of hydroxyl-rich nanoparticles in the lubricant composition is 1-5%, the mass fraction of the sorbitan fatty acid ester compound is 10-25%, and the mass fraction of the oily base fluid is 70-89%, based on the total mass of the lubricant composition.

[0011] Optionally, the oily base fluid is selected from at least one of mineral oil, synthetic hydrocarbon, and synthetic ester.

[0012] Optionally, the oily base fluid is selected from mineral oil.

[0013] Optionally, the mineral oil is HVIH-5 oil.

[0014] According to a second aspect of the present invention, there is provided a method for preparing a lubricant composition containing hydroxyl-rich nanoparticles, comprising at least the following steps:

[0015] Step (1): mixing a sorbitan fatty acid ester compound with an oily base liquid, heating and stirring to form a uniform sol;

[0016] Step (2): adding hydroxyl-rich nanoparticles to the sol obtained in step (1), heating and stirring to obtain a composite sol;

[0017] Step (3): The composite sol obtained in step (2) is allowed to stand and cool to obtain a lubricant composition containing hydroxyl-rich nanoparticles.

[0018] The mass mixing ratio of the sorbitol fatty acid ester compound and the oily base liquid in step (1) is 1:9 to 1:4;

[0019] In step (2), the mass mixing ratio of the hydroxyl-rich nanoparticles to the sol is 1:99 to 1:50;

[0020] Optionally, the heating and stirring in step (1) and step (2) are performed by a magnetic stirrer with a heating device.

[0021] Optionally, the heating and stirring conditions in step (1) and step (2) are as follows:

[0022] The heating and stirring temperature is 60-80°C;

[0023] The heating and stirring time is 1 to 3 hours.

[0024] Optionally, the cooling conditions in step (3) are as follows:

[0025] The cooling temperature is 10-30°C;

[0026] The cooling time is 1 to 3 hours.

[0027] According to a third aspect of the present invention, there is provided a method for constructing a friction protection film on a ferrous metal surface, the method comprising at least the following steps:

[0028] Step I: Clean and dry the iron-based metal to be processed to prepare the lower sample;

[0029] Step II: Select a metal material that matches the surface shape of the lower sample in step I, clean and dry it, and use it as the upper sample;

[0030] Step III: Adjust the matching state of the lower specimen in step I and the upper specimen in step II so that their surfaces are fully fitted together to form a contact interface with uniform force;

[0031] Step IV: continuously delivering the lubricant composition to the contact interface of step III by a peristaltic pump, while controlling the temperature of the contact interface of step III, and applying a load to the upper sample of step III;

[0032] Step V: The lower sample of the pair described in step III and the upper sample described in step IV are subjected to relative reciprocating motion, and then the lower sample is kept warm and cooled to obtain a lower sample containing a friction protection film.

[0033] Optionally, the metal material in step II is a cast iron sample with a diamond-like carbon coating.

[0034] The peristaltic pump delivery rate in step IV is 0.1 to 2 mL / min;

[0035] The temperature of the contact interface in step IV is 100 to 250° C.;

[0036] The load applied to the upper sample in step IV is 10 to 100 MPa.

[0037] Optionally, the temperature of the contact interface in step IV is independently selected from any value of 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, or a range between any two of the above points.

[0038] Optionally, the conditions for the reciprocating motion in step V are as follows:

[0039] The speed of the reciprocating motion is 0.1 to 0.5 m / s;

[0040] The reciprocating motion lasts for 1 to 3 hours.

[0041] Optionally, the speed of the reciprocating motion is independently selected from any value among 0.10m / s, 0.15m / s, 0.20m / s, 0.25m / s, 0.30m / s, 0.35m / s, 0.40m / s, 0.45m / s, 0.50m / s or a range between any two of the above points.

[0042] Optionally, the insulation conditions in step V are as follows:

[0043] The insulation temperature is 100-250°C;

[0044] The insulation time is 12 to 24 hours.

[0045] Optionally, the insulation temperature is independently selected from any value of 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, or a range between any two of the above points.

[0046] Optionally, the cooling conditions in step V are as follows:

[0047] The cooling temperature is 10-30°C;

[0048] The cooling time is 1 to 3 hours.

[0049] Optionally, the thickness of the friction protection film in the lower sample containing the friction protection film obtained in step V is 50 to 600 nm.

[0050] Optionally, the thickness of the friction protection film in the lower sample containing the friction protection film obtained in step V is independently selected from any value of 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm or a range value between any two of the above points.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1) The raw materials used in the present invention are cheap and readily available, and the preparation method of the lubricant composition and the construction method of the friction protection film are both relatively simple.

[0053] 2) The lubricant composition containing hydroxyl-rich nanoparticles of the present invention is in a gel-like state at room temperature, exhibiting excellent lubricating properties. The nanoparticles are uniformly dispersed in the lubricant composition and can be maintained for a long time. Furthermore, the lubricant composition containing hydroxyl-rich nanoparticles also has heat absorption capabilities.

[0054] 3) A friction and wear test was conducted using the hydroxyl-rich nanoparticle lubricant composition prepared by the present invention at 200° C. and 50 MPa for 12 hours. Compared with an oily base fluid, the friction coefficient was reduced by more than 50%.

[0055] 4) The method of preparing a friction protection film using a lubricant composition containing hydroxyl-rich nanoparticles proposed in the present invention can prepare a friction protection film with a thickness of 50 to 600 nm on the metal surface, which can effectively protect the friction interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the preparation process of the lubricant composition containing hydroxyl-rich nanoparticles in Example 1 of the present invention;

[0057] Figure 2 This is a comparison chart of HVIH-5 oil and the lubricant composition containing hydroxyl-rich nanoparticles obtained in Example 1 of the present invention;

[0058] Figure 3 This is a comparison chart of infrared results of HVIH-5 oil and the lubricant composition containing hydroxyl-rich nanoparticles obtained in Example 1 of the present invention;

[0059] Figure 4 This is a comparison chart of the heat absorption capacity of HVIH-5 oil and the lubricant composition containing hydroxyl-rich nanoparticles obtained in Example 1 of the present invention;

[0060] Figure 5 This is a comparison chart of the friction coefficients of HVIH-5 oil and the lubricant composition containing hydroxyl-rich nanoparticles obtained in Example 1 of the present invention;

[0061] Figure 6 This is a transmission electron micrograph of the lubricant composition containing hydroxyl-rich nanoparticles in Example 1 of the present invention filling and repairing damaged areas on a metal surface under a friction environment;

[0062] Figure 7 This is a transmission electron micrograph of a friction protection film prepared on a metal surface using the lubricant composition containing hydroxyl-rich nanoparticles obtained in Example 1 of the present invention;

[0063] Figure 8 This is a comparison chart of the friction coefficients of the iron-based metal surface with and without the friction protection film in Example 2 of the present invention;

[0064] Figure 9 Schematic diagram of the contact form of the sample during the construction of the friction protection film in Examples 2 to 3 of the present invention. DETAILED DESCRIPTION

[0065] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0066] Unless otherwise specified, the raw materials and reagents in the examples of the present invention were purchased through commercial channels. The HVIH-5 oil was purchased from Sinopec Group Corporation; the sorbitan monostearate powder and silica nanoparticles in Example 1 were obtained from Shanghai Aladdin Biochemical Technology Co., Ltd.; the lower samples in Examples 2 and 3 were cast iron samples and stainless steel 316 purchased from Yantai Wanster Co., Ltd., and the upper samples were cast iron samples with diamond-like carbon (DLC) coatings purchased from Yizheng Shuanghuan Piston Ring Co., Ltd.

[0067] The lubricant composition of Example 1 was analyzed using Fourier transform infrared spectroscopy to evaluate the dispersion stability of the nanoparticles in the lubricant;

[0068] Thermal analysis of the lubricant composition containing hydroxyl-rich nanoparticles obtained in Example 1 was performed using a differential scanning calorimeter;

[0069] The friction coefficient of the materials obtained in Examples 1 and 2 was measured using a reciprocating friction and wear tester;

[0070] The metal repair performance of the material obtained in Example 1 was characterized using a transmission electron microscope;

[0071] The thickness of the friction protection films obtained in Examples 2 and 3 was measured using a transmission electron microscope.

[0072] Example 1

[0073] 13 g of sorbitan monostearate powder was added to 100 mL of HVIH-5 oil and stirred at 65 ° C for 1 hour to form a uniform sol; then 2.5 g of silica nanoparticles (particle size 30 nm) was added to the above sol and stirred for 1 hour to obtain a composite sol; the composite sol was then allowed to stand and cool at 25 ° C for 3 hours to obtain a lubricant composition containing hydroxyl-rich nanoparticles.

[0074] Comparison of state: The lubricant composition containing hydroxyl-rich nanoparticles obtained in this example was compared with HVIH-5 oil. Figure 2 As shown, the results show that the lubricant composition obtained in this example is in a gel state, and there is no obvious stratification and agglomeration of nanoparticles in the composition.

[0075] Compared with the original HVIH-5 oil, the lubricant composition -1 、2853cm -1 and 1461cm -1The –CH2 stretching and bending vibration peaks nearby all show different degrees of red shift, indicating that hydrogen bonding or van der Waals interaction may occur between the oily base fluid and the hydroxyl-rich nanoparticles. This interaction is one of the key signs of the successful construction of the lubricant composition, indicating that the base fluid and the nanoparticles have achieved effective bonding, which helps to improve the stability of the system and the synergistic lubrication performance. In addition, the upper and lower spectra Figure 1 This further demonstrates that the system structure is stable and the composition is uniform.

[0076] Dispersion stability test of nanoparticles in the lubricant composition: The lubricant composition containing hydroxyl-rich nanoparticles obtained in this example was placed in a sealed container and allowed to stand for 30 days. Samples were then extracted from the bottom and top of the bottle and compared with the infrared spectrum of HVIH-5 oil. The results are as follows: Figure 3 It can be seen that compared with the HVIH-5 lubricant sample, the composition containing hydroxyl-rich nanoparticles newly appeared at 1098 cm in both the upper and lower sampling layers. -1 and 468cm -1 The Si-O characteristic peak at the 300 nm t is detected, and the peak intensities and peak shapes of the two are basically consistent, indicating that the silica nanoparticles do not settle or agglomerate in the lubricant composition and have good dispersion stability. In summary, the red shift phenomenon and the infrared characterization of the dispersion behavior jointly verified the successful construction of the lubricant composition containing hydroxyl-rich nanoparticles.

[0077] Comparison of differential scanning calorimetry: The lubricant composition containing hydroxyl-rich nanoparticles obtained in this example was subjected to differential scanning calorimetry analysis with HVIH-5 oil. Figure 4 As shown, it can be seen that the lubricant composition containing hydroxyl-rich nanoparticles has an obvious endothermic peak between 40 and 60° C., proving that the lubricant composition containing hydroxyl-rich nanoparticles has a certain heat absorption capacity.

[0078] Friction coefficient comparison: The lubricant composition containing hydroxyl-rich nanoparticles obtained in this example and HVIH-5 oil were subjected to friction and wear tests on diamond-like carbon (DLC)-cast iron friction pairs. The test results are shown in Figure 2. Figure 5 It can be seen that the friction coefficient of the lubricant composition containing hydroxyl-rich nanoparticles is 0.0411, which is 54.4% lower than that of the HVIH-5 oil.

[0079] Repair effect test: The lubricant composition containing hydroxyl-rich nanoparticles obtained in this example was used to repair the metal surface under a friction environment. The repair results are as follows: Figure 6 As shown in Figure 2, it can be seen that the damage pits on the surface of the metal substrate are filled and repaired.

[0080] Example 2

[0081] A friction protection film was prepared using the lubricant composition containing hydroxyl-rich nanoparticles obtained by the preparation method of Example 1. The cast iron sample to be processed was cleaned with alcohol for 15 minutes and dried as the lower sample. A metal material that matched the surface shape of the lower sample was selected, cleaned and dried to obtain the upper sample. The upper sample and the lower sample were tightly fitted to ensure good contact, and the temperature of the contact interface between the upper and lower samples was controlled to 200°C and the load was 10 MPa (the contact diagram is shown in FIG. 1 ). Figure 9 The lubricant composition containing hydroxyl-rich nanoparticles prepared in Example 1 was added to the contact interface between the upper sample and the lower sample at a flow rate of 0.1 mL / min by a peristaltic pump, and the lower sample and the upper sample were subjected to relative reciprocating motion at a relative speed of 0.2 m / s for 3 h; the lower sample was then placed in a constant temperature drying oven and kept at 200° C. for 12 h to obtain an iron-based metal sample containing a friction protective film with a thickness of 600 nm. The transmission electron microscope image of the friction protective film is shown in FIG. Figure 7 As shown, it can be seen from the electron microscope image that the friction protection film has a dense structure and uniform composition.

[0082] The cast iron sample without friction protection film was compared with the cast iron sample with friction protection film obtained in this embodiment in a tribological test. The cast iron sample with diamond coating was used as the upper sample. The friction coefficient test results were obtained under the working conditions of 10MPa, 200℃, and 0.2m / s. Figure 8 As shown in the figure, the results show that the friction coefficient of the cast iron sample without friction protection film is 0.0902, and the friction coefficient of the cast iron sample with friction protection film is 0.0490, which shows that the friction protection film can improve the tribological properties of cast iron and reduce friction.

[0083] Example 3

[0084] The difference from Example 2 is that 316 stainless steel is used as the lower sample, and the lubricant composition containing hydroxyl-rich nanoparticles prepared in Example 1 is added to the contact surface of the upper sample and the lower sample at a flow rate of 0.1 mL / min by a peristaltic pump. The temperature of the contact interface is 150°C, the load is 10 MPa, and the relative motion speed of the upper sample and the lower sample is 0.2 m / s (the contact diagram is shown in FIG. Figure 9 After 3 hours of reciprocating motion, the lower sample was placed in a constant temperature drying oven at 150°C for 12 hours to obtain a stainless steel sample with a friction protective film with a thickness of 200 nm.

[0085] The above descriptions are merely several embodiments of the present invention and do not constitute any form of limitation to the present invention. Although the present invention is disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Any technician familiar with the present profession who, without departing from the scope of the technical solution of the present invention, makes slight changes or modifications using the technical contents disclosed above are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A lubricant composition containing hydroxyl-rich nanoparticles, characterized in that: The lubricant composition comprises hydroxyl-rich nanoparticles, sorbitan fatty acid ester compounds and an oily base fluid; The sorbitan fatty acid ester compound is selected from at least one of sorbitan monostearate, sorbitan monooleate, and sorbitan tristearate; The hydroxyl-rich nanoparticles are selected from at least one of silicon dioxide nanoparticles, aluminum oxide nanoparticles, and titanium dioxide nanoparticles; The oily base fluid is selected from at least one of mineral oil, synthetic hydrocarbon, and synthetic ester.

2. The lubricant composition according to claim 1, wherein The mass fraction of the hydroxyl-rich nanoparticles in the lubricant composition is 1-5%, the mass fraction of the sorbitan fatty acid ester compound is 10-25%, and the mass fraction of the oily base fluid is 70-89%, based on the total mass of the lubricant composition; Preferably, the oily base fluid is mineral oil; Preferably, the sorbitan fatty acid ester compound is sorbitan monostearate.

3. The lubricant composition according to claim 1, wherein The particle size of the hydroxyl-rich nanoparticles is 20 to 50 nm.

4. A method for preparing a lubricant composition containing hydroxyl-rich nanoparticles according to any one of claims 1 to 3, characterized in that: At least the following steps are included: Step (1): mixing a sorbitan fatty acid ester compound with an oily base liquid, heating and stirring to form a uniform sol; Step (2): adding hydroxyl-rich nanoparticles to the sol obtained in step (1), heating and stirring to obtain a composite sol; Step (3): The composite sol obtained in step (2) is allowed to stand and cool to obtain a lubricant composition containing hydroxyl-rich nanoparticles.

5. The preparation method according to claim 4, characterized in that The mass mixing ratio of the sorbitol fatty acid ester compound and the oily base liquid in step (1) is 1:9 to 1:4; The mass mixing ratio of the hydroxyl-rich nanoparticles and the sol in step (2) is 1:99 to 1:19; Preferably, the mineral oil is HVIH-5 oil; Preferably, the heating and stirring conditions in step (1) and step (2) are as follows: The heating and stirring temperature is 60-80°C; The heating and stirring time is 1 to 3 hours.

6. The preparation method according to claim 4, characterized in that The cooling conditions in step (3) are as follows: The cooling temperature is 10-30°C; The cooling time is 1 to 3 hours.

7. A method for constructing a friction protection film on an iron-based metal surface, characterized in that: The method comprises at least the following steps: Step I: Clean and dry the iron-based metal to be processed to prepare the lower sample; Step II: Select a metal material that matches the surface shape of the lower sample in step I, clean and dry it, and use it as the upper sample; Step III: Adjust the matching state of the lower specimen in step I and the upper specimen in step II so that their surfaces are fully fitted together to form a contact interface with uniform force; Step IV: continuously delivering the lubricant composition to the contact interface of step III by a peristaltic pump, while controlling the temperature of the contact interface of step III, and applying a load to the upper sample of step III; Step V: causing the lower sample described in step III and the upper sample described in step IV to undergo relative reciprocating motion, and then keeping the lower sample warm and cooling it to obtain a lower sample containing a friction protective film; The lubricant composition is selected from the lubricant composition according to any one of claims 1 to 3 and / or is prepared by the preparation method of the lubricant composition according to any one of claims 4 to 6.

8. The method for constructing a friction protection film on an iron-based metal surface according to claim 7, characterized in that: The metal material in step II is a cast iron sample with a diamond-like carbon coating. Preferably, the delivery rate in step IV is 0.1 to 2 mL / min; The temperature of the contact interface in step IV is 100 to 250° C.; The load applied to the upper sample in step IV is 10 to 100 MPa.

9. The method for constructing a friction protection film on an iron-based metal surface according to claim 7, characterized in that: The conditions for the reciprocating motion in step V are as follows: The speed of the reciprocating motion is 0.1 to 0.5 m / s; The reciprocating motion lasts for 1 to 3 hours.

10. The method for constructing a friction protection film on an iron-based metal surface according to claim 7, characterized in that: The holding conditions in step V are as follows: The insulation temperature is 100-250°C; The insulation time is 12 to 24 hours; Preferably, the cooling conditions in step V are as follows: The cooling temperature is 10-30°C; The cooling time is 1 to 3 hours; Preferably, the thickness of the friction protection film in the lower sample containing the friction protection film obtained in step V is 50 to 600 nm.

Images