Preparation method of fullerene-containing metal wear self-repairing material for transmission lubricating system

Abstract

The invention discloses a preparation method of a fullerene-containing metal wear self-repairing material for a transmission lubricating system, and relates to the technical field of lubricating materials. Comprising the following steps: (1) pretreating raw materials, and preparing artificially synthesized nano hydroxyl magnesium silicate, fullerene-nano indium composite powder and micro-nano composite hydroxyl magnesium silicate powder; (2) preparing a fullerene-indium-copper-lithium quaternary composite dispersion liquid; (3) mixing the micro-nano composite hydroxyl magnesium silicate powder and the composite dispersion liquid in the modified base oil in a gradient manner, and adding an antioxidant and an anti-settling agent; and (4) regulating the particle size to D50 = 500-800nm and the viscosity to 150-200mm / s at 40 DEG C, and carrying out vacuum degassing and packaging to obtain a finished product. According to the method, shutdown-free in-situ repair of the worn surface of the transmission system is achieved, the friction coefficient is reduced to 0.02-0.06, the hardness of the metal surface is improved by 1-2 times, and the service life of equipment is prolonged by one time or above.

Description

Technical Field

[0001] This invention relates to the field of lubrication materials technology, specifically to a method for preparing a fullerene-containing metal wear self-repairing material for transmission lubrication systems. Background Technology

[0002] Metal wear in transmission systems (such as wind turbine gearboxes and automotive transmissions) is a major cause of equipment failure. Gearboxes are the leading cause of unplanned downtime in wind turbines, with approximately 60% of gear damage caused by surface fatigue (pitting) and electrochemical corrosion. Pitting is a common fatigue damage in gear transmissions, primarily occurring in the contact area between the primary and secondary gears within the gearbox. During gear meshing, the contact stress on the tooth surface changes periodically. If the stress exceeds the material's contact fatigue limit, microcracks will form on the tooth surface due to fatigue. As these cracks propagate, the surface metal peels off, forming pitted pits (i.e., pitting). Pitting disrupts the meshing state of the tooth surface, leading to decreased transmission efficiency, increased vibration and noise, and in severe cases, excessive damage to the tooth surface can cause gear failure. Gear damage accounts for 60% of all gearbox component failures, with pitting accounting for 31%. If not treated promptly and effectively, it can progress to deep pitting and tooth breakage.

[0003] Stray currents or electrostatic discharges in electrical systems can cause numerous small, smooth-edged pits on the gear teeth due to the arcs or sparks emitted from the gaps between the meshing gear teeth. This results in large-area burns on the tooth surface, with the edges exhibiting a tempered color, leading to electrochemical corrosion or arc ablation on the metal surface. This commonly occurs within the warranty period of components such as gearboxes and bearings in wind turbines, creating a significant hidden danger for gear failure. Gear damage accounts for 60% of all gearbox component failures. Electrolytic corrosion forms tiny pits, pits, or ablation marks on the metal surface, damaging the smoothness and precision of components. For transmission components such as gears and bearings, surface damage leads to increased friction coefficients and reduced fit precision, resulting in vibration, noise, and shortened service life. The pits formed by electrolytic corrosion can become stress concentration points, accelerating the initiation and propagation of fatigue cracks and increasing the risk of fracture.

[0004] Traditional repair methods rely on downtime and disassembly, which are costly and inefficient. Existing self-healing materials mostly use single nanoparticles (such as magnesium hydroxysilicate and graphene), which suffer from poor dispersibility, low repair efficiency, and insufficient high-temperature stability. For example, natural magnesium hydroxysilicate mineral powder has low purity (impurity content >5%), and the nano-metal particles are prone to oxidation and agglomeration, making it difficult to form a uniform reinforcing layer at the friction interface.

[0005] Fullerene (C 60As a zero-dimensional nanomaterial, fullerene possesses excellent mechanical strength (hardness > 100 GPa) and lubrication performance (friction coefficient < 0.03), but its dispersion stability in lubricating oil is poor, and its interfacial bonding with metal surfaces is weak. Therefore, there is an urgent need to develop a composite self-healing material with fullerene as the core, in synergy with nano-hydroxy magnesium silicate and metal catalysts, to solve the integrated problem of "dispersion-repair-wear resistance". Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a fullerene-containing self-repairing material for transmission lubrication systems. This method fills in-situ electro-erosion micro-pits, seals the entrance to pitting cracks, and generates a gradient metal-ceramic reinforcement layer. This enables in-situ repair of worn surfaces in transmission systems without downtime, reduces the coefficient of friction to 0.02-0.06, increases the surface hardness of metal by 1-2 times, extends equipment life by more than 1 time, inhibits pitting initiation, repairs electro-erosion pits, and prevents further deterioration.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: a method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system, comprising the following steps: 1. Raw material pretreatment to prepare artificially synthesized nano-hydroxy magnesium silicate, fullerene-nano indium composite powder and micro-nano composite hydroxy magnesium silicate powder; 2. Preparation of fullerene-indium-copper-lithium quaternary composite dispersion; 3. The micro-nano composite magnesium hydroxysilicate powder and the composite dispersion are gradient-mixed in the modified base oil, and antioxidants and anti-settling agents are added. 4. Adjust the particle size to D50=500-800nm ​​and the viscosity to 150-200mm² / s at 40℃, then degas and seal under vacuum to obtain the finished product.

[0008] Preferably, the preparation of artificially synthesized nano-hydroxy magnesium silicate in step 1 includes: preparing a mixed solution of MgCl2·6H2O, Na2SiO3·9H2O and NaOH according to the stoichiometric ratio, hydrothermally reacting at 150-250℃ for 20-30 hours, and then ball-milling the product to a particle size of 50-100nm with a purity ≥99.5% after centrifugation, washing, freeze-drying.

[0009] Preferably, the preparation of the fullerene-indium nanocomposite powder in step 1 includes: C 60 Fullerene and nano-indium powder are mixed at a mass ratio of 9:1, ultrasonically dispersed in anhydrous ethanol for 35-45 minutes, calcined at 250-350℃ for 1-3 hours under Ar gas protection, and then ball-milled until the particle size is ≤100nm.

[0010] Preferably, the preparation of the micro-nano composite magnesium hydroxysilicate powder in step 1 includes: mixing artificially synthesized nano magnesium hydroxysilicate and natural micro-nano mineral powder magnesium hydroxysilicate at a mass ratio of 1:3, adding 0.2-0.8wt% silane coupling agent KH-550, and stirring at high speed for 20-40 minutes.

[0011] Preferably, the preparation of the quaternary composite dispersion in step 2 includes: mixing fullerene-indium composite powder with nano-Cu powder and nano-Li powder in a mass ratio of 8:2:1, adding PAO-40 and 0.5-2wt% polyisobutylene-succinimide dispersant, and ultrasonically dispersing for 55-65 minutes.

[0012] Preferably, in step 3, the modified base oil is a compound system of PAO-60 and 3-6 wt% polyether ether ketone thickener, the micro-nano composite magnesium hydroxysilicate powder accounts for 30-50% of the total mass, and the composite dispersion accounts for 5-15% of the total mass.

[0013] Preferably, step 3 further includes adding 0.8 wt% of antioxidant 2,6-di-tert-butyl-p-cresol and 0.5 wt% of gaseous SiO2 anti-settling agent, and stirring at 1200 rpm for 2-4 hours under nitrogen protection.

[0014] Preferably, the material can generate a 5-10 μm metal-ceramic coating in situ at a friction flash temperature of 200-600℃, with a friction coefficient of 0.02-0.06 and a 1-2 times increase in metal surface hardness.

[0015] The present invention has the following beneficial effects: 1. Fullerenes provide an ultra-low friction interface, nano-indium / copper catalyzes the formation of a metal-ceramic coating (Al2O3-SiO2-MgO composite phase), artificially synthesized nano-hydroxy magnesium silicate fills the wear gaps, and micro-nano mineral powders enhance the load-bearing capacity. 2. Dispersion stability: Through a three-step modification process of "ultrasound-calcination-coupling agent", the problem of fullerene aggregation is solved, and the dispersion stability is ≥6 months (no precipitation after standing). 3. Green and environmentally friendly: It does not contain heavy metals, has good compatibility with lubricating oil, has no toxic side effects during use, and complies with RoHS standards; 4. Through multi-component synergistic design, this invention integrates for the first time the in-situ filling of electro-erosion micropits and the inhibition of pitting crack propagation into a single self-healing system. The fullerene-indium-copper catalytic system can trigger an in-situ reaction on the metal surface under friction flash temperature, generating a dense gradient metal-ceramic coating (5–10 μm) at the arc pits formed by electro-erosion, effectively sealing the conductive channels and preventing further discharge ablation. Simultaneously, artificially synthesized nano-hydroxy magnesium silicate is precisely embedded in the pitting spalling area, filling the fatigue crack inlet, and forming a metallurgical bond with the matrix under the action of the catalyst, significantly improving the tooth surface load-bearing capacity and fatigue resistance. This mechanism achieves a leap from "passive lubrication" to "active repair + performance enhancement," fundamentally delaying the gear failure process, and is particularly suitable for high-load, long-cycle operation scenarios such as wind turbine gearboxes. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0017] This specific embodiment adopts the following technical solution: A method for preparing a fullerene-containing metal wear self-repairing material for a transmission lubrication system, comprising the following steps: Step 1: Raw material pretreatment 1.1 Preparation of Artificially Synthesized Nano-Hydroxymagnesium Silicate Weigh out MgCl₂·6H₂O, Na₂SiO₃·9H₂O, and NaOH according to stoichiometric ratio, and dissolve them in deionized water to prepare a mixed solution (Mg²⁺ concentration 0.5 mol / L, Si²⁺ concentration 0.5 mol / L). 4 The product (Mg6[Si4O3]2:3) was transferred to a high-pressure reactor and hydrothermally reacted at 150-250℃ for 20-30 hours. After centrifugation, washing (pH=7), and freeze-drying, the product was ball-milled to a particle size of 50-100 nm to obtain synthetic nano-hydroxy magnesium silicate (Mg6[Si4O3]2) with a purity ≥99.5%. 10 [OH]8).

[0018] 1.2 Preparation of Fullerene-Indium Nanoparticle Composite Powder C 60 Fullerene (purity ≥99%, particle size 20-50nm) and indium nanoparticles (particle size 50-80nm, purity ≥99.9%) were mixed at a mass ratio of 9:1, added to anhydrous ethanol, and ultrasonically dispersed for 35-45 minutes (power 600W, frequency 25kHz). Then, the mixture was calcined at 250-350℃ for 1-3 hours under an inert atmosphere (Ar protection). After cooling, the mixture was ball-milled until the particle size was ≤100nm to obtain fullerene-indium composite powder (indium nanoparticles were loaded on the surface of the fullerene to enhance catalytic activity).

[0019] 1.3 Modification of magnesium hydroxysilicate from micro / nano mineral powder Natural magnesium hydroxysilicate mineral powder (particle size 1.0-3.0μm) was selected, and impurities were removed by air classification (purity ≥98%). It was then mixed with the artificially synthesized nano-hydroxysilicate prepared in step 1.1 at a mass ratio of 3:1. 0.2-0.8wt% silane coupling agent (KH-550) was added, and the mixture was stirred at high speed (3000rpm) for 30 minutes to obtain "micro-nano composite magnesium hydroxysilicate powder" (balancing cost and repair efficiency).

[0020] Step 2: Preparation of composite dispersion 2.1 Fullerene-Indium Dispersion The fullerene-indium composite powder prepared in step 1.2 was added to polyalphaolefin synthetic oil (PAO-40), and 1.0 wt% dispersant (polyisobutylene succinimide) was added. The mixture was ultrasonically dispersed for 55-65 minutes (power 800W) to form a stable dispersion with a concentration of 5 wt%.

[0021] 2.2 Nano-metal catalyst dispersion Weigh out nano-Cu powder (particle size 30-50nm) and nano-Li powder (particle size 20-40nm) at a mass ratio of Cu:Li=3:1, add them to the dispersion in step 2.1, and continue ultrasonic dispersion for 30 minutes to obtain a fullerene-indium-copper-lithium quaternary composite dispersion.

[0022] Step 3: Material Composites and Interface Control 3.1 Base Oil Mixing Add modified polyether ether ketone (PEEK) thickener (5% of the base oil mass) and PAO-60 base oil to the reactor, heat to 80°C, stir (800 rpm) until completely dissolved, then add the "micro-nano composite magnesium hydroxysilicate powder" (40% of the total mass) from step 1.3, heat to 100°C, and keep stirring for 2 hours.

[0023] 3.2 Synergistic Combination of Multiple Components Cool to 60°C, slowly add the fullerene-indium-copper-lithium dispersion from step 2.2 (10% of the total mass), while simultaneously purging with nitrogen for protection. Increase the stirring speed to 1200 rpm and mix for 2-4 hours. During this time, add 0.8 wt% antioxidant (2,6-di-tert-butyl-p-cresol) and 0.5 wt% anti-settling agent (gas phase SiO2).

[0024] Step 4: Performance Optimization and Packaging 4.1 Particle size and viscosity control The particle size distribution of the composite system was monitored by a laser particle size analyzer (D50=500-800nm), and the viscosity was adjusted to 150-200mm² / s at 40℃ using a rotational viscometer (if the viscosity is too high, add PAO-40; if it is too low, add 0.3wt% hydrogenated castor oil).

[0025] 4.2 Vacuum Degassing and Packaging The material is degassed for 30 minutes under a vacuum of ≤-0.09MPa and 60℃ to remove air bubbles. After removal, the material is packaged into sealed containers and protected with nitrogen to obtain the finished product.

[0026] The self-healing material in this specific embodiment achieves transmission system wear repair through a "multi-component synergistic in-situ reaction" mechanism: It uses artificially synthesized nano-hydroxy magnesium silicate (high purity) and micro-nano mineral powder hydroxy magnesium silicate (low cost) as the main repair phases, fullerene-nano indium composite powder as the lubrication-catalysis core, supplemented by nano-Cu-Li catalyst and modified base oil. After entering the friction pair through the lubricating oil circulation system, at a friction flash temperature of 200-600℃, fullerene provides an ultra-low friction interface, and nano-indium / copper catalyzes the in-situ oxidation reaction between the hydroxy magnesium silicate and the metal surface, generating a gradient structure metal-ceramic coating (a dense bonding matrix at the bottom, a tough buffer in the middle, and a fullerene friction-reducing layer at the surface), simultaneously filling the wear gaps and improving surface hardness, achieving integrated "repair-strengthening-lubrication".

[0027] Example 1: This example provides a self-healing material specifically for wind turbine gearboxes. The raw material ratio is as follows: 15 parts of artificially synthesized nano-hydroxy magnesium silicate, 45 parts of micro / nano mineral powder hydroxy magnesium silicate, 8 parts of fullerene-indium composite powder, 2 parts of nano-Cu-Li catalyst, 28 parts of PAO-60 base oil, 1 part of dispersant, 0.8 parts of antioxidant, and 0.2 parts of anti-settling agent. The preparation process is as follows: Prepare according to steps 1-4, wherein the ultrasonic dispersion time of the fullerene-indium composite powder is extended to 80 minutes to ensure uniform dispersion.

[0028] The performance test results of this embodiment are as follows: After injecting 5L of material into a 1.5MW wind turbine gearbox and running for 3 months, the coefficient of friction decreased from 0.18 to 0.035, the gearbox oil temperature decreased by 8℃, a 5-8μm metal-ceramic coating (hardness HV850, original substrate hardness HV350) was formed on the metal surface, the equipment vibration value decreased by 30%, and the expected lifespan was extended to more than 1 times the original design value.

[0029] Example 2: This example provides a low-viscosity self-healing material for automotive transmissions. The difference between this example and Example 1 is that the raw materials are adjusted as follows: the base oil is replaced with PAO-30 (lower viscosity), the fullerene-indium composite powder is reduced to 50g, and 10g of nano-graphene (particle size 10-30nm) is added to improve lubricity.

[0030] The performance test application of this embodiment is as follows: In a certain type of automobile transmission (lubricating oil viscosity 120mm² / s at 40℃): the coefficient of friction was reduced to 0.028, and the shifting resistance was reduced by 25%; after continuous operation for 50,000 kilometers, the transmission was not disassembled or repaired, and the wear was reduced by 80%.

[0031] Example 3: This example provides a high-temperature wear-resistant material for industrial gearboxes. The difference between this example and Example 1 is that the raw materials are adjusted as follows: Nano-metal catalyst optimization: Based on the original Cu-Li catalyst, 10g of nano ZrO2 (particle size 30-60nm, purity ≥99.9%, good high-temperature stability) is added to form a "Cu-Li-ZrO2 ternary catalyst" (mass ratio Cu:Li:ZrO2=3:1:1), which improves the catalytic activity and metal-ceramic coating density at high temperatures; Base oil selection: PAO-100 fully synthetic oil (viscosity index >400, kinematic viscosity ≥15mm² / s at 300℃) is used to ensure the oil film strength at high temperatures; Thickening system: 8wt% polyimide (PI) micro powder (particle size 1-3μm) is added to enhance the material's resistance to leaching at high temperatures.

[0032] The preparation process was optimized as follows: 0.3wt% of high-temperature dispersant (polydimethylsiloxane) was introduced during the ultrasonic dispersion of fullerene-indium composite powder to avoid high-temperature agglomeration; in step 3, the reaction temperature was increased to 120℃ and the stirring time was extended to 3 hours to promote the interfacial bonding between ZrO2 and magnesium hydroxysilicate.

[0033] This embodiment is applied as follows: 8L of material was injected into an industrial gearbox (load 1000 N·m, speed 1500 rpm) operating continuously at 300℃. After 6 months of operation: Tribological properties: The coefficient of friction stabilized at 0.045±0.005, with no lubrication failure or oil film rupture, a reduction of 62.5% compared to traditional high-temperature grease (coefficient of friction 0.12); Metal-ceramic coating characteristics: A 10μm uniform metal-ceramic coating was formed on the worn surface, the main component of which was a MgSiO3-ZrO2 composite phase (hardness HV920, oxidation resistance at high temperature improved by 40%); High-temperature stability: After 2000 hours of continuous operation at 300℃, the viscosity change rate of the material was <5%, with no precipitation or stratification, no pitting corrosion, adhesion or other failure modes on the metal surface, and no new pitting spots appeared; Economic benefits: The overhaul cycle of the gearbox was extended from 6 months to 18 months, the amount of high-temperature lubricating oil replaced was reduced by 75%, and the annual maintenance cost was reduced by approximately RMB 120,000 per unit.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system, characterized in that, Includes the following steps: (1) Raw material pretreatment to prepare artificially synthesized nano-hydroxy magnesium silicate, fullerene-nano indium composite powder and micro-nano composite hydroxy magnesium silicate powder; (2) Preparation of fullerene-indium-copper-lithium quaternary composite dispersion; (3) The micro-nano composite magnesium hydroxysilicate powder and the composite dispersion are mixed in a gradient in the modified base oil, and antioxidants and anti-settling agents are added. (4) Adjust the particle size to D50=500-800nm ​​and the viscosity to 150-200mm² / s at 40℃, and then degas and encapsulate the finished product.

2. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, The preparation of artificially synthesized nano-hydroxy magnesium silicate in step (1) includes: preparing a mixed solution of MgCl2·6H2O, Na2SiO3·9H2O and NaOH according to the stoichiometric ratio, hydrothermally reacting at 150-250℃ for 20-30 hours, and then ball milling the product to a particle size of 50-100nm after centrifugation, washing, freeze drying and purity ≥99.5%.

3. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, The preparation of fullerene-indium nanocomposite powder in step (1) includes: C 60 Fullerene and nano-indium powder are mixed at a mass ratio of 9:1, ultrasonically dispersed in anhydrous ethanol for 35-45 minutes, calcined at 250-350℃ for 1-3 hours under Ar gas protection, and then ball-milled until the particle size is ≤100nm.

4. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, The preparation of micro-nano composite magnesium hydroxysilicate powder in step (1) includes: mixing artificially synthesized nano magnesium hydroxysilicate and natural micro-nano mineral powder magnesium hydroxysilicate at a mass ratio of 1:3, adding 0.2-0.8wt% silane coupling agent KH-550, and stirring at high speed for 20-40 minutes.

5. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, The preparation of the quaternary composite dispersion in step (2) includes: mixing fullerene-indium composite powder with nano-Cu powder and nano-Li powder in a mass ratio of 8:2:1, adding PAO-40 and 0.5-2wt% polyisobutylene-succinimide dispersant, and ultrasonically dispersing for 55-65 minutes.

6. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, In step (3), the modified base oil is a compound system of PAO-60 and 3-6 wt% polyether ether ketone thickener, the micro-nano composite magnesium hydroxysilicate powder accounts for 30-50% of the total mass, and the composite dispersion accounts for 5-15% of the total mass.

7. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, The step (3) also includes adding 0.8 wt% of antioxidant 2,6-di-tert-butyl-p-cresol and 0.5 wt% gaseous SiO2 anti-settling agent, and stirring at 1200 rpm for 2-4 hours under nitrogen protection.

8. The method for preparing a fullerene-containing self-repairing metal wear material for a transmission lubrication system according to claim 1, characterized in that, The material can generate a 5-10 μm metal-ceramic coating in situ at a friction flash temperature of 200-600℃, with a friction coefficient of 0.02-0.06 and a 1-2 times increase in metal surface hardness.