Nano-copper micro-pitting repairing agent and preparation method thereof

Abstract

The preparation method comprises the following steps: adding 6-10 parts of organic amine into 100-500 parts of carbon disulfide, uniformly mixing at 0-30 DEG C, then adding 2-5 parts of an inorganic copper salt aqueous solution, uniformly mixing, then adding 1-2 parts of stronger ammonia water and 1-2 parts of hydrazine hydrate, reacting for 1-5 hours, washing an organic phase with deionized water, and drying to obtain the nano-copper micro-pitting repairing agent. And carrying out rotary evaporation on the organic phase to obtain viscous brownish black liquid of the thiocarbamic acid modified copper nanoparticles. The particle size range of the copper nanoparticles is regulated and controlled to be 2-30 nanometers by changing the molecular structure of the organic amine. Copper nanoparticles with different particle sizes are reasonably proportioned and added into gear oil to serve as a lubricating agent and a repairing agent respectively, and meanwhile, the micro-pitting-resistant gear oil is formed by utilizing the oxidation resistance of a modifier. The method disclosed by the invention is low in cost, simple in raw material and preparation process and stable in production batch, can effectively solve the triple functions of gear oil lubrication, micro-pitting repair and oxidation resistance, can be used for gear boxes of wind power equipment, and improves the shear fatigue resistance of gears and the oxidation aging resistance of lubricating oil.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, and particularly relates to a nano-copper micro-pitting repair agent and its preparation method. Background Technology

[0002] Micropitting is one of the most common and highly destructive failure types in gear transmission systems. During the operation of gearboxes in large equipment such as wind power, tunnel boring machines, aerospace, and heavy machinery, gear pairs are subjected to harsh conditions of high load, high speed, and cyclic shear stress for extended periods. After millions or even hundreds of millions of stress cycles, the gear surface and subsurface are prone to developing microcracks and micropits due to plastic deformation and contact fatigue—a phenomenon known as micropitting. The occurrence of micropitting directly exacerbates gear wear and equipment vibration. If not effectively suppressed, these micro-defects will continue to expand, eventually leading to macro-pitting, tooth surface spalling, and even fatal failures such as tooth breakage. This severely impacts the operational stability and service life of the equipment, while significantly increasing maintenance costs and downtime losses. With the rapid development of high-end equipment manufacturing, the increasing size and extreme operating conditions of equipment place higher demands on the anti-micropitting, friction-reducing, wear-resistant, and long-term stable properties of gear oils. Developing multi-functional anti-micropitting lubricant additives and complementary oils has become a key technological bottleneck driving the development of the high-end equipment manufacturing field.

[0003] Currently, commercial gear oil anti-micropitting additives are mainly composed of small-molecule sulfides, phosphates, and carboxylic acid esters. While these small-molecule additives can improve the lubrication performance of gear oil to some extent, their core drawback lies in their limited functionality. They can only achieve basic friction reduction and anti-wear or stress buffering, lacking the ability to repair existing micropitting pits and microcracks in situ. They cannot fundamentally curb the occurrence and expansion of micropitting, only delaying the onset of failure, and are insufficient to meet the long-term protection requirements of high-end equipment, as illustrated in Chinese patent applications CN 105567402 A and CN 114540103 A. To compensate for the shortcomings of small-molecule additives, some technical solutions attempt to add solid particulate additives such as calcium carbonate nanoparticles and flake graphite to gear oil, as illustrated in Chinese patent applications CN 201610221235.2 and CN 109609249 A, aiming to improve friction reduction and anti-wear performance. However, this technology still has significant shortcomings: calcium carbonate nanoparticles have weak friction-reducing capabilities and are difficult to adapt to high-load shear conditions; flake graphite has limited load-bearing capacity and is prone to oxidation failure at high temperatures; more importantly, these solid particles are mostly designed with a single particle size, which cannot achieve targeted action on micro-defects of different scales on the gear surface. They cannot effectively repair micro-pitting corrosion, nor can they simultaneously achieve multiple functions such as lubrication, anti-wear, and stress dispersion. In addition, the dispersion stability of solid particles with base oil is poor, and they are prone to agglomeration and sedimentation during long-term operation, resulting in rapid performance degradation of gear oil and difficulty in guaranteeing batch stability.

[0004] In view of this, this application was developed. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a nano-copper micro-pitting repair agent. It utilizes dialkyl dithiocarbamate as a modifier to in-situ modify copper nanoparticles, controlling particle growth while addressing their tendency to agglomerate and oxidize in lubricating oil. This results in copper nanoparticles with uniform particle size, stable dispersion, and antioxidant capabilities. By altering the structure of the alkyl chain in the modifier, the particle size of the copper nanoparticles can be controlled, allowing for the production of copper nanoparticles with different particle sizes. Particle size By appropriately combining microparticles of different sizes and adding them to gear oil as a repair agent, the functions of anti-oxidation, friction reduction and wear resistance, and micro-pitting repair can be achieved simultaneously.

[0006] The present invention also provides a method for preparing the above-mentioned nano-copper micro-pitting repair agent.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a nano-copper micro-pitting corrosion repair agent includes the following steps: (1) Mix the organic amine with carbon disulfide at 0-30°C; (2) Then add an aqueous solution of inorganic copper salt, mix well, then add concentrated ammonia and hydrazine hydrate, react for 1-5 hours, and wash the organic phase with deionized water; (3) Rotary evaporation of the organic phase yielded a viscous brown liquid, which was copper nanoparticles of different sizes modified with thiocarbamate. (4) The copper nanoparticles of different particle sizes prepared in steps (1) to (3) are mixed in a certain reasonable ratio to obtain a solution that can simultaneously satisfy multiple functions of lubrication and micro-pitting repair.

[0008] Specifically, in step (4), the proportion of copper nanoparticles with different particle sizes is as follows: by weight percentage, copper nanoparticles with a particle size range of 2-6 nanometers account for 40-60% of the repair agent, copper nanoparticles with a particle size range of 7-15 nanometers account for 20-30% of the repair agent, and copper nanoparticles with a particle size range of 16-30 nanometers account for 20-30% of the repair agent.

[0009] Specifically, the organic amine mentioned in step (1) can be one or more combinations of primary amines, secondary amines, etc., of straight-chain or branched alkanes with 4-16 carbon atoms; more preferably, the organic amine includes, but is not limited to, at least one of oleylamine, palmitamine, myristicamine, laurylamine, isooctylamine, butylamine, etc. The particle size of copper nanoparticles can be controlled by changing the molecular structure of the organic amine, and the particle size error of copper nanoparticles obtained by a single reaction is ≤2 nanometers, and the particle size of copper nanoparticles can be controlled within the range of 2-30 nanometers.

[0010] Furthermore, the concentration of the inorganic copper salt aqueous solution in step (2) is 0.05-0.5 mol / L; the inorganic copper salt can be one or more of copper sulfate, copper chloride, copper nitrate, etc.

[0011] Further preferred, by weight, the composition includes 4-10 parts organic amine, 100-500 parts carbon disulfide, 2-5 parts inorganic copper salt aqueous solution, 1-2 parts concentrated ammonia, and 1-2 parts hydrazine hydrate. The hydrazine hydrate used is a 70-80% hydrazine hydrate aqueous solution.

[0012] This invention provides a nano-copper micro-pitting corrosion repair agent prepared by the above-described method. The particle size of copper nanoparticles can be controlled by altering the molecular structure of organic amines, and the particle size error of copper nanoparticles obtained from a single reaction is ≤2 nm; the particle size of copper nanoparticles can be controlled within the range of 2-30 nm.

[0013] The present invention also provides the application of the above-mentioned nano-copper micro-pitting repair agent as a micro-pitting repair agent.

[0014] The present invention also provides the application of the above-mentioned nano-copper micro-pitting repair agent as a lubricant, friction reducer, anti-wear agent or antioxidant.

[0015] The present invention also provides a gear oil comprising the aforementioned nano-copper micropitting repair agent. Further, the nano-copper micropitting repair agent is added to the gear oil at a weight percentage of 0.5-2%.

[0016] As a preferred technical solution, the preparation method of the nano-copper micro-pitting corrosion repair agent includes the following specific steps: (1) Add 6-10 parts of organic amine to 100-500 parts of carbon disulfide and stir at 0-30°C for 1-3 hours to mix evenly; (2) Then add 2-5 parts of an inorganic copper salt aqueous solution with a concentration of 0.05-0.5 mol / L and stir evenly. Then add 1-2 parts of concentrated ammonia and 1-2 parts of hydrazine hydrate, react for 1-5 hours, and wash the organic phase with deionized water. (3) Rotary evaporation of the organic phase yields a viscous brown liquid, which is copper nanoparticles of different sizes modified with thiocarbamate. (4) Mix the copper nanoparticles of different particle sizes obtained by steps (1) to (3) in a certain proportion to obtain the final product.

[0017] This invention involves adding copper nanoparticles of different particle sizes to gear oil in a rational ratio, serving as both a lubricant and a repair agent. Simultaneously, the antioxidant properties of the modifier are utilized to form a gear oil resistant to micropitting. This invention offers a low-cost method with simple raw materials and preparation processes, ensuring stable production batches. It effectively addresses the triple functions of gear oil lubrication, micropitting repair, and antioxidant properties, and can be used in wind turbine gearboxes to improve gear resistance to shear fatigue and the lubricant's resistance to oxidation and aging.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: This invention utilizes dialkyldithiocarbamate as a modifier to generate copper nanoparticles in situ. While controlling the growth of copper nanoparticles, it addresses their tendency to agglomerate and oxidize in lubricating oil, resulting in copper nanoparticles with uniform particle size, stable dispersion, and antioxidant capabilities. By altering the structure of the alkyl chain in the modifier, the particle size of the copper nanoparticles can be controlled, allowing for the production of copper nanoparticles with different particle sizes. Particle size By rationally combining copper nanoparticles of varying sizes and adding them to gear oil as a repair agent, the invention can simultaneously achieve antioxidant, friction-reducing, wear-resistant, and micro-pitting repair functions. The preparation method of this invention is simple, low-cost, and suitable for large-scale industrial production, showing broad application prospects in the field of fatigue-resistant lubricants. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Transmission electron microscopy (TEM) images of copper nanoparticles of different sizes modified with thiocarbamate prepared in Examples 1(a), 2(b), 3(c), 4(d), 5(e), and 6(f). Figure 2 The results of rotating oxygen bomb tests before and after adding different amounts of Example 7 nano copper micropitting repair agent to gear oil; Figure 3 Images showing the micropitting repair process of gear oil containing the nano-copper micropitting repair agent prepared in Example 7. Figure 4 Images showing the experimental process of micropitting in gear oil without the nano-copper micropitting repair agent prepared in Example 7; Figure 5 For the micropitting repair experiment with the addition of single-size copper nanoparticles, A has a particle size of 2.5 nm and B has a particle size of 27 nm. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following examples and comparative examples, the parts are by weight, and each part weighs 1 g.

[0023] In the following examples, all raw materials used are commercially available products that can be directly purchased, or can be prepared using conventional techniques in the art. Concentrated ammonia water refers to an aqueous solution containing 25%–28% ammonia. The hydrazine hydrate used is an 80% aqueous solution of hydrazine hydrate. Example 1

[0024] A method for preparing copper nanoparticles of different particle sizes modified with thiocarbamate is as follows: (1) Add 7 parts of oleylamine to 300 parts of carbon disulfide and stir at 30°C for 1 hour to mix well; (2) Then add 3 parts of copper sulfate aqueous solution with a concentration of 0.1 mol / L and stir well. Then add 1 part of concentrated ammonia and 1 part of hydrazine hydrate. React for 1 hour and wash the organic phase with deionized water. (3) The organic phase was rotary evaporated to obtain a viscous brown liquid of copper nanoparticles modified with dithiocarbamate.

[0025] Transmission electron microscopy images of the prepared dithiocarbamate-modified copper nanoparticles are shown below. Figure 1 (a). By Figure 1 (a) It can be seen that the prepared copper nanoparticles modified with dithiocarbamate have uniform particle size, are dispersed without agglomeration, and have an average particle size of 2.5 nanometers. Example 2

[0026] A method for preparing copper nanoparticles of different particle sizes modified with thiocarbamate is as follows: (1) Add 5 parts of palmitamine to 400 parts of carbon disulfide and stir at 25°C for 1.5 hours to mix.

[0027] (2) Then add 4 parts of copper chloride salt aqueous solution with a concentration of 0.1 mol / L and stir well. Then add 1.5 parts of concentrated ammonia and 1.5 parts of hydrazine hydrate, react for 2 hours, and wash the organic phase with deionized water. (3) The organic phase was rotary evaporated to obtain a viscous brown liquid of copper nanoparticles modified with dithiodipalmitocarbamate.

[0028] Transmission electron microscopy images of the prepared dithiodipalmitocarbamic acid-modified copper nanoparticles are shown below. Figure 1 (b). By Figure 1 (b) It can be seen that the prepared copper nanoparticles modified with dithiodipalmitocarbamate have uniform particle size, are dispersed without agglomeration, and have an average particle size of 6.0 nm. Example 3

[0029] A method for preparing copper nanoparticles of different particle sizes modified with thiocarbamate is as follows: (1) Add 6 parts of myristicin to 500 parts of carbon disulfide and stir at 25°C for 2.0 hours to mix.

[0030] (2) Then add 4 parts of copper chloride salt aqueous solution with a concentration of 0.1 mol / L and stir well. Then add 1.5 parts of concentrated ammonia and 1.5 parts of hydrazine hydrate, react for 2.5 hours, and wash the organic phase with deionized water. (3) The organic phase was rotary evaporated to obtain a viscous brown liquid of copper nanoparticles modified with dithiomyristocarbamic acid.

[0031] Transmission electron microscopy images of the prepared dithiomyristate-modified copper nanoparticles are shown below. Figure 1 (c). By Figure 1 (c) It can be seen that the prepared copper nanoparticles modified with dithiomyristate carbamate have uniform particle size, are dispersed without agglomeration, and have an average particle size of 10.0 nanometers. Example 4

[0032] A method for preparing copper nanoparticles of different particle sizes modified with thiocarbamate is as follows: (1) Add 6 parts laurylamine to 500 parts carbon disulfide and stir at 20°C for 2.0 hours to mix.

[0033] (2) Then add 5 parts of copper nitrate aqueous solution with a concentration of 0.2 mol / L and stir well. Then add 1.5 parts of concentrated ammonia and 1.5 parts of hydrazine hydrate, react for 3.0 hours, and wash the organic phase with deionized water. (3) The organic phase was rotary evaporated to obtain a viscous brown liquid of copper nanoparticles modified with dithiodilauric acid.

[0034] Transmission electron microscopy images of the copper nanoparticles modified with dithiodilaurcaric acid are shown below. Figure 1 (d). By Figure 1 (d) It can be seen that the prepared copper nanoparticles modified with dithiodilaurcaric acid have uniform particle size, are dispersed without agglomeration, and have an average particle size of 14.0 nm. Example 5

[0035] A method for preparing copper nanoparticles of different particle sizes modified with thiocarbamate is as follows: (1) Add 5 parts of isooctylamine to 500 parts of carbon disulfide and stir at 25°C for 2.0 hours to mix.

[0036] (2) Then add 5 parts of copper nitrate aqueous solution with a concentration of 0.3 mol / L and stir well. Then add 2 parts of concentrated ammonia and 2 parts of hydrazine hydrate. React for 4.0 hours and wash the organic phase with deionized water. (3) The organic phase was rotary evaporated to obtain a viscous brown liquid of copper nanoparticles modified with dithiodiisooctylcarbamate.

[0037] Transmission electron microscopy (TEM) images of the copper nanoparticles modified with dithiodiisooctylcarbamate (DIOC) are shown below. Figure 1 (e). By Figure 1 (e) It can be seen that the prepared copper nanoparticles modified with dithiodiisooctylcarbamate have uniform particle size, are dispersed without agglomeration, and have an average particle size of 20.5 nm. Example 6

[0038] A method for preparing copper nanoparticles of different particle sizes modified with thiocarbamate is as follows: (1) Add 7 parts of butylamine to 500 parts of carbon disulfide and stir at 5°C for 2.0 hours to mix.

[0039] (2) Then add 5 parts of copper nitrate aqueous solution with a concentration of 0.5 mol / L and stir well. Then add 2 parts of concentrated ammonia and 2 parts of hydrazine hydrate. React for 4.0 hours and wash the organic phase with deionized water. (3) The organic phase was rotary evaporated to obtain a viscous brown liquid of copper nanoparticles modified with dithiodibutylcarbamate.

[0040] Transmission electron microscopy images of the copper nanoparticles modified with dithiodibutylcarbamate are shown below. Figure 1 (f). By Figure 1 (f) It can be seen that the prepared copper nanoparticles modified with dithiodibutylcarbamate have uniform particle size, are dispersed without agglomeration, and have an average particle size of 27.0 nm. Example 7

[0041] The thiocarbamate-modified copper nanoparticles of different sizes prepared in Examples 1-6 were formulated into a nano-copper micro-pitting corrosion repair agent according to the following weight percentages: Copper nanoparticles with a particle size of 2.5 nanometers (product of Example 1) account for 20% of the repair agent. Copper nanoparticles with a particle size of 6.0 nanometers (product of Example 2) account for 20% of the repair agent. Copper nanoparticles with a particle size of 10 nanometers (product of Example 3) accounted for 20%. Copper nanoparticles with a particle size of 14.0 nanometers (product of Example 4) accounted for 10%. Copper nanoparticles with a particle size of 20.5 nanometers (product of Example 5) accounted for 15%. Copper nanoparticles with a particle size of 27.0 nanometers (product of Example 6) accounted for 15%.

[0042] The prepared nano-copper micro-pitting corrosion repair agent was added to gear oil at different mass percentages (0%, 0.5%, 1.0%, 1.5%), and its antioxidant performance was tested using the rotating oxygen bomb method. The results are as follows: Figure 2 As shown. From Figure 2 The results show that the antioxidant capacity of gear oil is significantly improved after adding nano copper micro-pitting repair agent, and the antioxidant capacity increases with the amount added.

[0043] Micropitting repair experiments were conducted on gear oil using a micropitting tester (MPR). First, in the micropitting test, gear oil without added modifiers developed micropits on the roller surface after millions of friction cycles. The more friction cycles, the larger and more pronounced the micropits became (e.g., ...). Figure 4 (As shown). Then, 1.5% of the nano-copper micro-pitting repair agent prepared in Example 7 was added to the gear oil, and the micro-pitting experiment was performed again. The results are shown in [Figure 7]. Figure 3 .like Figure 3 As shown, after 800,000 friction cycles, the pit has begun to be filled with repair agent. As the number of friction cycles increases, the pit is gradually filled with repair agent, resulting in a gradual reduction in the pit area (see photos of 1.6 million and 2.4 million cycles in the figure). When it reaches 3.2 million cycles, the pit has been filled and repaired, and a friction-reducing and anti-wear friction film has also formed on the roller surface.

[0044] Finally, this application conducted a micropitting corrosion repair experiment on single-size nano-copper, and the results are shown in […]. Figure 5 Adding 1.5% of 2.5nm nano-copper (Example 1 product) to gear oil that developed micropitting resulted in the micropitting failing to be repaired after 3.2 million cycles (e.g., ...). Figure 5 (As shown in A). Furthermore, adding 1.5% of 27.0 nm particle size nano-copper (Example 6 product) to the gear oil that caused micropitting also failed to repair the micropitting after 3.2 million cycles (as shown in A). Figure 5 (As shown in B). This demonstrates that nano-copper repair agents with a reasonable ratio of multiple particle sizes possess the ability to repair micro-pitting corrosion, as well as friction reduction and wear resistance; while nano-copper with a single particle size does not possess the corresponding effects.

Claims

1. A method for preparing a nano-copper micro-pitting corrosion repair agent, characterized in that, Includes the following steps: (1) Mix the organic amine with carbon disulfide at 0-30°C; (2) Then add an aqueous solution of inorganic copper salt, mix well, then add concentrated ammonia and hydrazine hydrate, react for 1-5 hours, and wash the organic phase with deionized water; (3) Rotary evaporation of the organic phase yielded a viscous brown liquid, which was copper nanoparticles of different sizes modified with thiocarbamate. (4) Mix the copper nanoparticles of different particle sizes obtained by steps (1) to (3) in a certain proportion to obtain the final product.

2. The preparation method of the nano-copper micro-pitting corrosion repair agent as described in claim 1, characterized in that, In step (4), the proportions of copper nanoparticles with different particle sizes are as follows: by weight percentage, 40-60% copper nanoparticles with a particle size of 2-6 nanometers, 20-30% copper nanoparticles with a particle size of 7-15 nanometers, and 20-30% copper nanoparticles with a particle size of 16-30 nanometers.

3. The preparation method of the nano-copper micro-pitting corrosion repair agent as described in claim 1, characterized in that, The organic amine is one or more combinations of primary and secondary amines of straight-chain or branched alkanes with 4-16 carbon atoms; the particle size of copper nanoparticles can be controlled by changing the molecular structure of the organic amine, and the particle size of copper nanoparticles can be controlled within the range of 2-30 nanometers.

4. The preparation method of the nano-copper micro-pitting corrosion repair agent as described in claim 1, characterized in that, The concentration of the inorganic copper salt aqueous solution is 0.05-0.5 mol / L; the inorganic copper salt is one or a combination of copper sulfate, copper chloride, and copper nitrate.

5. The preparation method of the nano-copper micro-pitting corrosion repair agent as described in claim 1, characterized in that, By weight, the contents are: 4-10 parts organic amine, 100-500 parts carbon disulfide, 2-5 parts inorganic copper salt aqueous solution, 1-2 parts concentrated ammonia, and 1-2 parts hydrazine hydrate.

6. The nano-copper micro-pitting repair agent prepared by any one of the preparation methods described in claims 1 to 5.

7. The application of the nano-copper micro-pitting corrosion repair agent according to claim 6 as a micro-pitting corrosion repair agent.

8. The use of the nano-copper micro-pitting repair agent according to claim 6 as a lubricant, friction reducer, anti-wear agent or antioxidant.

9. A gear oil, characterized in that, It contains the nano-copper micro-pitting repair agent as described in claim 6.

10. The gear oil as described in claim 8, characterized in that, The nano-copper micro-pitting repair agent is added to the gear oil at a weight percentage of 0.5-2%.

Images