Lubricating oil for generating nano silicon dioxide in situ through friction as well as preparation method and application of lubricating oil

Abstract

The invention discloses lubricating oil for generating nano silicon dioxide in situ through friction as well as a preparation method and application of the lubricating oil, and belongs to the technical field of lubricating oil. The lubricating oil is composed of a silane coupling agent gamma-glycidyl ether oxypropyl trimethoxy silane and gear oil, in the application process of the lubricating oil, gamma-glycidyl ether oxypropyl trimethoxy silane can generate nano-particles in situ in a friction area, so that the generated nano-particles are good in dispersity, and the lubricating oil can be used for lubricating the gear. The problem that nano-particles cannot enter a friction area due to agglomeration is avoided, the nano-particles are directly generated in situ in the friction area, so that the lubricating effect is better, the application range is wider, and a four-ball test shows that the lubricating oil has obvious antifriction and antiwear effects.

Description

Technical Field

[0001] The invention belongs to the technical field of lubricating oils, and in particular relates to a lubricating oil for in-situ generation of nano silicon dioxide by friction, and a preparation method and application thereof. Background Art

[0002] In the broad field of mechanical engineering, friction and wear, as inevitable physical phenomena, have long been key factors affecting equipment performance, stability and service life. With the rapid development of modern industrial technology, especially the continuous progress in high-end manufacturing, aerospace, precision instruments and other fields, the requirements for lubrication technology are becoming increasingly stringent. Although traditional lubricant additives have alleviated the friction and wear problems to a certain extent, their lubrication effect is limited under extreme working conditions (such as high temperature, high pressure, and high-speed operation), and some additive ingredients (such as P and S elements) pose a potential threat to the environment, which does not meet the current requirements of green and sustainable development.

[0003] In order to overcome these challenges, the application of nanotechnology in the field of lubricant additives has shown great potential. Nano additives, with their extremely small size advantage, can easily penetrate into the friction interface and significantly reduce the friction coefficient and wear volume through various mechanisms such as forming a protective film, micro-polishing, filling wear micro-pits and promoting rolling friction. In addition, compared with traditional organic additives, nano additives are more environmentally friendly and reduce the negative impact on the ecological environment.

[0004] However, the widespread use of nano-additives still faces certain problems, such as dispersion stability. Since nanoparticles have high surface energy, they are very likely to attract each other and agglomerate into larger particles in the lubricating fluid, which not only weakens the lubricating effect of the nano-additives, but may also lead to serious consequences such as blockage of the lubrication system. Therefore, how to effectively improve the dispersion stability of nanoparticles in lubricating fluids has become a key technical problem restricting the development of nano-lubricants.

[0005] Although there are many methods to try to solve this problem, including physical dispersion (such as mechanical stirring, ultrasonic treatment, high-energy treatment, etc.) and chemical dispersion (such as surface chemical modification, adding dispersants, etc.), these methods have limitations to varying degrees in practical applications. Physical dispersion methods are often inefficient and energy-intensive, while chemical dispersion methods may involve complex processes and high costs, and the durability of the dispersion effect remains to be verified. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a lubricating oil that generates nano-silicon dioxide in situ by friction, and a preparation method and application thereof, so as to solve the problem in the prior art that nanoparticles in the lubricating oil are easily attracted to each other and agglomerated, resulting in poor dispersion stability in the lubricating oil, thereby affecting the lubrication effect.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A lubricating oil for in-situ generation of nano-silicon dioxide by friction, comprising γ-glycidyloxypropyltrimethoxysilane and gear oil;

[0009] The lubricating oil can generate granular nano silicon dioxide in situ when lubricating the friction pair.

[0010] A further improvement of the present invention is:

[0011] Preferably, in the lubricating oil, the mass proportion of the γ-glycidyloxypropyltrimethoxysilane is 0.2-1%, and the remainder is gear oil.

[0012] Preferably, in the lubricating oil, the mass proportion of the γ-glycidyloxypropyltrimethoxysilane is 0.2%, and the remainder is gear oil.

[0013] Preferably, the diameter of the granular nano-silicon dioxide is 180-220 nm.

[0014] A method for preparing the above-mentioned lubricating oil for in-situ generation of nano-silicon dioxide by friction comprises the following steps: adding γ-glycidyloxypropyltrimethoxysilane into gear oil, stirring with constant temperature magnetic force, and then subjecting to ultrasonic treatment to obtain the lubricating oil.

[0015] Preferably, the added amount of γ-glycidyloxypropyltrimethoxysilane is 0.2-1% of the mass of the lubricating oil.

[0016] Preferably, the constant temperature magnetic stirring time is 30 to 40 minutes, and the stirring temperature is 40 to 50°C.

[0017] Preferably, the constant temperature magnetic stirring speed is 800-1000 rpm.

[0018] Preferably, the ultrasonic treatment time is 30 to 40 minutes.

[0019] The application of the lubricating oil that generates nano-silicon dioxide in situ during friction is used to lubricate friction pairs. During the friction process, the gamma-glycidyloxypropyltrimethoxysilane in the lubricating oil generates granular nano-silicon dioxide in situ.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention discloses a lubricating oil capable of generating nano silicon dioxide in situ by friction. The lubricating oil is composed of a silane coupling agent, γ-glycidyloxypropyltrimethoxysilane, and gear oil. During the application process, the lubricating oil can generate nano particles in situ in the friction area, so that the generated nano particles have good dispersibility, and the problem that the nano particles cannot enter the friction area due to agglomeration is avoided. The lubricating effect is better and the application range is wider. The four-ball test shows that the prepared lubricating oil has obvious friction reduction and anti-wear effects.

[0022] Furthermore, through the four-ball test, it was found that when the mass of γ-glycidyloxypropyltrimethoxysilane is 0.2% of the mass of the lubricating oil, the anti-wear effect is the best. If the addition amount is too much, the generated nanoparticles tend to aggregate in the contact area, resulting in a decrease in the lubrication effect.

[0023] The present invention also discloses a method for preparing a lubricating oil for in-situ generation of nano silicon dioxide by friction, wherein γ-glycidyloxypropyltrimethoxysilane is added to gear oil in proportion, stirred on a constant temperature magnetic stirrer, and then the obtained oil is ultrasonically treated in an ultrasonic cleaning machine to obtain the lubricating oil. The preparation method has a simple process, can avoid measures such as adding a dispersant to ensure the dispersion effect of nano silicon dioxide, and reduce process costs.

[0024] The present invention also discloses the use of a lubricating oil capable of generating nano silicon dioxide in situ by friction, and when the lubricating oil is used to lubricate a friction pair, silicon dioxide nanoparticles can be generated in situ. The present invention firstly finds that when the lubricating oil is used, the silane coupling agent can generate nano additives - granular silicon dioxide in situ, which can reduce friction and prevent the aggregation of granular silicon dioxide nano additives while playing a role in reducing friction and resisting wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A flow chart of a method for preparing lubricating oil based on in-situ generation of nano-silicon dioxide on the surface of a friction pair provided in an embodiment of the present invention.

[0026] Figure 2 The friction coefficient variation curves over time when the mass percentages of γ-glycidyloxypropyltrimethoxysilane provided in Examples 1 to 5 of the present invention are 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1% respectively.

[0027] Figure 3 The wear spot diameter diagrams are provided for embodiments 1 to 5 of the present invention when the mass percentages of γ-glycidyloxypropyltrimethoxysilane are 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1% respectively.

[0028] Figure 4This is an electron microscope image of the surface morphology of nano-silicon dioxide generated in situ on the friction pair surface provided in Example 1 of the present invention.

[0029] Figure 5 This is a graph showing the change in friction coefficient over time in a four-ball test of Example 6 of the present invention.

[0030] Figure 6 This is a light microscopic image of the wear spot surface of the four-ball test in Example 6 of the present invention;

[0031] Among them, (a) shows the wear spot surface without adding KH560; (b) shows the wear morphology after adding 0.2% KH560;

[0032] Figure 7 This is a graph showing the variation of the friction coefficient over time in Example 7 of the present invention;

[0033] Figure 8 This is a light microscopic image of the wear spot surface of Example 7 of the present invention;

[0034] Among them, (a) shows the wear spot surface without adding KH560; (b) shows the wear morphology after adding 0.2% KH560. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0036] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0037] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0038] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0039] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0040] Friction and wear are common phenomena that seriously affect the stability and reliability of mechanical devices. With the continuous upgrading of mechanical equipment, the requirements for lubrication are getting higher and higher. On the one hand, traditional lubricant additives are difficult to meet the lubrication needs under harsh working conditions. On the other hand, some additives containing elements such as P and S will pollute the environment. Nano additives are small in size and can easily enter the friction area and reduce friction and wear through film formation, polishing, filling and rolling. Compared with traditional organic additives, they are less polluting to the environment.

[0041] Adding nanoparticles to lubricating oil can significantly improve the performance of the lubricating oil and protect mechanical equipment from damage.

[0042] However, there is a serious problem with nano additives. Due to the high surface energy of nano particles, the particles are easily attracted to each other and agglomerated during use, resulting in poor dispersion stability in lubricating oil. In addition, the working environment of lubricating oil is usually a high temperature and high pressure environment. The high temperature environment intensifies the thermal motion of nano particles and increases the chance of mutual collision, thereby promoting the aggregation of particles. Under high pressure conditions, the nano particles in the lubricating oil may be subjected to stronger compression, resulting in a decrease in the distance between particles, and then aggregation. The aggregated nano particles may form larger particles or block aggregates, which become abrasive particles between friction pairs, but aggravate the wear of the equipment. It will also affect the stability, cleanliness and dispersibility of the lubricating oil, thereby reducing the overall use effect of the lubricating oil. This has greatly hindered the development of nano lubricants. Although there are some methods such as physical dispersion including mechanical stirring dispersion, ultrasonic dispersion, high energy treatment dispersion, chemical dispersion including surface chemical modification, dispersant dispersion and other methods that can improve the dispersion stability of nano particles, there are still shortcomings such as high modification cost and short stability time.

[0043] In order to solve the above problems, the present invention discloses a lubricating oil for in-situ generation of nano-silicon dioxide during friction, the lubricating oil is composed of γ-glycidyloxypropyltrimethoxysilane and gear oil; the lubricating oil can generate nano-silicon dioxide in-situ when lubricating the friction pair. The method generates nanoparticles in-situ in the friction area, avoiding the problem that the nanoparticles cannot enter the friction area due to agglomeration, and the lubrication effect is better.

[0044] Among them, γ-glycidyloxypropyltrimethoxysilane is KH-560 silane coupling agent, which is an epoxy functional silane. As an adhesion promoter, it is widely used in sulfides, ethyl formate, epoxy, acrylic fillers, sealants and adhesives; KH-560 silane coupling agent has good hydrolysis stability and reactivity, and can be hydrolyzed in water or organic solvents to generate silanol groups.

[0045] Gear oil can form an oil film in the gear transmission system to separate the gear surfaces, thereby reducing direct contact and friction, reducing the wear rate, and extending the service life of the gears; it can also take away the heat generated by friction, allowing the gears to be in a suitable working environment.

[0046] As a preferred solution, the mass proportion of γ-glycidyloxypropyltrimethoxysilane in the lubricating oil is 0.2% to 1%. By adjusting the amount of γ-glycidyloxypropyltrimethoxysilane added, the morphology, friction coefficient and wear spot diameter of the final generated nanoparticles can be affected. When the addition amount is 0.2%, the anti-wear effect is the best. If the addition amount is too much, the generated nanoparticles tend to gather in the contact area, resulting in a decrease in the lubrication effect.

[0047] As a preferred solution, the in-situ generated nano-silicon dioxide has a particle size of 180-220 nm and can be used as nano-friction particles to lubricate the friction pair.

[0048] The second aspect of the present invention discloses a method for preparing a lubricating oil that generates nano-silica in situ by friction, and the specific steps are: measuring a set amount of base oil, measuring a set amount of γ-glycidyloxypropyltrimethoxysilane and adding it to the base oil, stirring on a constant temperature magnetic stirrer, and then ultrasonically treating it in an ultrasonic cleaning machine.

[0049] Preferably, the base oil is gear oil, and the additive is γ-glycidyloxypropyltrimethoxysilane.

[0050] Preferably, the constant temperature magnetic stirrer has a stirring time of 30 to 40 minutes, a temperature of 40 to 50° C., and a rotation speed of 800 to 1000 rpm. At this temperature and rotation speed, the gear oil and the additive can be fully and evenly mixed.

[0051] Preferably, the ultrasonic treatment time is 30 to 40 minutes, and the gear oil and additives can be fully dispersed through the ultrasonic treatment.

[0052] Preferably, the total mass percentage content of γ-glycidyloxypropyltrimethoxysilane in the gear oil is 0.2% to 1%.

[0053] The third aspect of the present invention discloses the use of a lubricating oil for in-situ generation of nano-silicon dioxide by friction. When the lubricating oil lubricates a friction pair, the friction force causes the silane-oxygen bond in the silane coupling agent γ-glycidyloxypropyltrimethoxysilane to break, thereby generating nano-silicon dioxide.

[0054] During the application process, the lubricating oil can generate nanoparticles in situ in the friction area, so that the generated nanoparticles have good dispersion, avoiding the problem that the nanoparticles cannot enter the friction area due to agglomeration. The lubrication effect is better and the application range is wider. The four-ball test shows that the prepared lubricating oil has obvious friction reduction and anti-wear effects.

[0055] The four-ball test of the present invention refers to the standard NB / SH / T 0189-2017 to test the friction coefficient and wear spot diameter under the conditions of a load of 392N, a temperature of 75°C, and a rotation speed of 1000rpm. Compared with the case without additives, the friction coefficient and the wear spot diameter are reduced in the range of 0.2% to 1% by mass percentage of additives, with the friction coefficient reduced by up to 28.4% and the wear spot diameter reduced by up to 53.4%.

[0056] The four-ball test is a widely used bench test for evaluating the anti-wear and extreme pressure properties of lubricants. The principle of the four-ball test is based on the friction and wear behavior of four steel balls under specific conditions. In the test, grease or lubricating oil is usually loaded into a ball box, and the upper steel ball rotates under a specified load and speed, and contacts and rubs with the three stationary steel balls below. The anti-wear and pressure resistance of the lubricant are evaluated by measuring parameters such as the wear spot diameter and friction coefficient after a certain period of time.

[0057] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0058] Example 1

[0059] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0060] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 0.2%.

[0061] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0062] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0063] Example 2

[0064] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0065] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 0.4%.

[0066] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0067] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0068] Example 3

[0069] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0070] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 0.6%.

[0071] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0072] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0073] Example 4

[0074] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0075] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 0.8%.

[0076] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0077] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0078] Example 5

[0079] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0080] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 1%.

[0081] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0082] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0083] See also Figure 2Through the four-ball test, it was found that adding different amounts of KH-560 would reduce the friction coefficient. When the addition amount was 0.2%, the friction coefficient was the lowest and stable, indicating that the generated nano-silica had a significant friction reduction effect.

[0084] See also Figure 3 Through the four-ball test, it was found that adding different amounts of KH-560 would reduce the wear spot diameter relative to that without adding. When the addition amount was 0.2%, the reduction was the largest, about 54%, and the anti-wear effect was significant. When the addition amount was too much, the generated nanoparticles would gather in the contact area, resulting in a decrease in the lubrication effect.

[0085] See also Figure 4 , which is an electron microscope image of the surface morphology of the nano-silicon dioxide generated in situ on the friction pair provided in Example 1. It can be seen from the image that the particle size is about 200nm.

[0086] Example 6

[0087] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0088] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 0.2%.

[0089] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0090] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0091] (5) The prepared lubricating oil is subjected to a four-ball test, the four-ball test speed is 800 rpm, the test force is 392 N, the test temperature is 75° C., and the test time is 30 min.

[0092] See also Figure 5 This is a friction coefficient diagram under the conditions of a speed of 800rpm, a load of 392N, and a temperature of 75℃. From the figure, it can be seen that the friction coefficient without adding KH560 shows a trend of first rising, then falling, and then rising again. The initial rise is because the actual contact area increases with the progress of the running-in period, resulting in an increase in the friction coefficient. The subsequent decrease is due to the formation of a protective film by some additives in the gear oil. The final increase is due to the disappearance of the protective film on the friction surface. The friction coefficient with the addition of 0.2% KH560 is lower than that without addition, and is relatively stable, indicating that after adding KH560, nanoparticles are continuously generated during the friction process, acting as rolling bearings or depositing films in the contact area, thereby reducing friction.

[0093] Figure 6Figure (a) shows the wear spot surface without adding KH560. Many furrows can be seen, indicating severe abrasive wear, and the wear spot diameter is 807μm. Figure (b) shows the wear morphology after adding 0.2% KH560. The wear spot diameter is only 379μm, and the wear is significantly reduced.

[0094] Example 7

[0095] (1) Measure an appropriate amount of gear oil and pour it into a beaker.

[0096] (2) Take an appropriate amount of γ-glycidyloxypropyltrimethoxysilane and add it to the gear oil so that its mass percentage is 0.2%.

[0097] (3) Adjust the constant temperature magnetic stirrer to 40°C, 1000 rpm, and stir for 30 min.

[0098] (4) The stirred oil is placed in an ultrasonic cleaning machine for ultrasonic treatment for 30 minutes.

[0099] (5) The prepared lubricating oil is subjected to a four-ball test, the four-ball test speed is 1000 rpm, the test force is 196 N, the test temperature is 75° C., and the test time is 30 min.

[0100] See also Figure 7 It can be seen that the overall friction coefficient decreases after adding KH560, and the fluctuation range is smaller.

[0101] Figure 8 Figure (a) shows the wear spot surface without adding KH560. The wear form is mainly abrasive wear, and the wear spot diameter is 629μm; Figure (b) shows the wear morphology after adding 0.2% KH560. The wear spot diameter is 347μm, and the wear is significantly reduced.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lubricating oil for in-situ generation of nano-silicon dioxide by friction, characterized in that: It is composed of γ-glycidyloxypropyltrimethoxysilane and gear oil; The lubricating oil can generate granular nano silicon dioxide in situ when lubricating the friction pair.

2. The lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 1, characterized in that: In the lubricating oil, the mass proportion of the γ-glycidyloxypropyltrimethoxysilane is 0.2-1%, and the remainder is gear oil.

3. The lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 1, characterized in that: In the lubricating oil, the mass proportion of the γ-glycidyloxypropyltrimethoxysilane is 0.2%, and the remainder is gear oil.

4. The lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 1, characterized in that: The diameter of the granular nano silicon dioxide is 180-220 nm.

5. A method for preparing a lubricating oil for in-situ generation of nano-silicon dioxide by friction as claimed in claim 1, characterized in that: The method comprises the following steps: adding gamma-glycidyl ether oxypropyl trimethoxy silane into gear oil, stirring the gear oil at a constant temperature with magnetic force, and then subjecting the mixture to ultrasonic treatment to obtain lubricating oil.

6. The method for preparing lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 5, characterized in that: The added amount of γ-glycidyloxypropyltrimethoxysilane is 0.2-1% of the mass of the lubricating oil.

7. The method for preparing lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 5, characterized in that: The constant temperature magnetic stirring time is 30 to 40 minutes, and the stirring temperature is 40 to 50°C.

8. The method for preparing lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 5, characterized in that: The constant temperature magnetic stirring speed is 800-1000 rpm.

9. The method for preparing lubricating oil for in-situ generation of nano-silicon dioxide by friction according to claim 5, characterized in that: The ultrasonic treatment time is 30 to 40 minutes.

10. The use of the lubricating oil for in-situ generation of nano-silicon dioxide by friction as claimed in claim 1, characterized in that: Used to lubricate friction pairs, during the friction process, the γ-glycidyloxypropyltrimethoxysilane in the lubricating oil generates granular nano-silicon dioxide in situ.

Images