Bionic self-repairing nanocomposite cutting fluid and preparation method thereof

Abstract

This invention relates to the field of cutting fluids, particularly to a biomimetic self-healing nanocomposite cutting fluid and its preparation method. The cutting fluid is composed of the following components by mass percentage: 5-10% lubricant, 2-5% extreme pressure anti-wear agent, 0.1-2% nanofunctional agent, 1-3% surfactant, 1-2% corrosion inhibitor, 0.5-1.5% pH stabilizer, 0.1-0.5% defoamer, 0.1-0.5% corrosion inhibitor, and the remainder being deionized water. This invention creatively introduces nanofunctional agents such as MXene and nanodiamond. These nanomaterials can form a high-strength, low-friction penetrating layer and repair film on the tool surface. During cutting, they actively fill the microscopic defects caused by tool wear, thereby achieving a "self-healing" effect. This characteristic can significantly reduce the coefficient of friction and cutting force between the tool and the workpiece, and tests have shown that it can extend tool life by more than 50%.

Description

Technical Field

[0001] This invention relates to the field of cutting fluids, and in particular to a biomimetic self-healing nanocomposite cutting fluid and its preparation method. Background Technology

[0002] Stainless steel is widely used in aerospace, medical devices, precision instruments, and kitchen and bathroom products due to its excellent corrosion resistance, high strength, and good aesthetics. However, stainless steel itself has problems such as severe work hardening tendency, low thermal conductivity, high cutting force, and easy chip adhesion, making it a typical difficult-to-machine material. This places extremely high demands on the cutting fluid used in its machining process. The cutting fluid must have excellent lubricity, cooling, penetration, and anti-sintering properties. Currently, most stainless steel cutting fluids on the market add sulfur- or chlorine-containing extreme pressure additives to improve their extreme pressure anti-wear properties. Although these additives can improve the cutting effect to a certain extent, they have obvious drawbacks: sulfur-based additives may cause corrosion of metal parts such as copper and silver and produce an odor; chlorine-based additives may decompose to produce hydrochloric acid at high temperatures or when exposed to water, leading to corrosion of machine tools and workpieces, and chlorinated organic matter is environmentally unfriendly and poses potential health risks. In addition, traditional mineral oil-based cutting fluids have poor biodegradability, while high-performance synthetic ester products are expensive. A more prominent problem is that existing cutting fluids primarily provide passive protection for cutting tools, failing to effectively address microscopic wear and resulting in limited tool life extension. Furthermore, the waste fluid generated after use by most traditional cutting fluids is difficult and costly to treat, and the mineral oil and various additives are difficult to separate, easily causing environmental burden, which contradicts the current trend of green manufacturing. With the development of nanomaterials technology, its application to cutting fluids to improve overall performance has become a research hotspot. For example, nanoparticles, due to their small size effect and large specific surface area, hold promise for forming a highly efficient lubricating film between friction pairs. However, how to solve the agglomeration of nanoparticles in the base fluid, achieve long-term stable dispersion, and ensure that they produce a synergistic effect with other additives in the lubrication system rather than mutual interference remains a technical bottleneck restricting their practical application. Therefore, developing an innovative stainless steel cutting fluid that combines excellent machining performance (especially the ability to actively protect cutting tools and extend their lifespan), environmental friendliness, and easy waste fluid treatment after use has become an urgent technical challenge for those skilled in the art. Summary of the Invention

[0003] The technical problem this invention aims to solve is as follows: To address the technical problems described in the background art, this invention provides a biomimetic self-healing nanocomposite cutting fluid and its preparation method. This invention creatively introduces nanofunctional agents such as MXene and nanodiamond. These nanomaterials can form a high-strength, low-friction penetrating layer and repair film on the tool surface. During cutting, they can act like "intelligent filler materials," actively filling the microscopic defects caused by tool wear, thereby achieving a "self-healing" effect. This characteristic can significantly reduce the coefficient of friction and cutting force between the tool and the workpiece, and tests have shown that it can extend tool life by more than 50%.

[0004] Through the synergistic effect of nanofunctional agents and chlorine- and sulfur-free organic borate ester extreme pressure anti-wear agents, a robust iron boride and carbon-based composite protective film can be formed on the tool and workpiece surfaces under the high temperature and high pressure environment of the cutting zone. This protective film effectively prevents work hardening of stainless steel and material sticking to the tool, thereby achieving higher machining accuracy and better workpiece surface finish.

[0005] The formulation system of this invention completely eliminates substances such as sulfur and chlorine that are harmful to the environment and human health, reducing pollution at the source. The modified vegetable oils and other components in the formulation have better biodegradability, further reducing environmental impact.

[0006] This invention employs a unique step-by-step dispersion process of "premixing-high-speed shearing-ultrasonic activation-high-pressure homogenization." This composite process effectively solves the problem of nanoparticle aggregation in the liquid phase, ensuring the long-term and stable dispersion of nanofunctional agents in the cutting fluid system. The resulting product exhibits good storage stability, showing no sedimentation or stratification after more than 12 months, guaranteeing the consistency of product performance.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A biomimetic self-healing nanocomposite cutting fluid is composed of the following components by mass percentage: 5-10% lubricant, 2-5% extreme pressure anti-wear agent, 0.1-2% nanofunctional agent, 1-3% surfactant, 1-2% corrosion inhibitor, 0.5-1.5% pH stabilizer, 0.1-0.5% defoamer, 0.1-0.5% preservative, and the remainder is deionized water;

[0009] The lubricant is a compound of modified vegetable oil and synthetic ester, with a compounding mass ratio of 1:1 to 3:1;

[0010] The extreme pressure anti-wear agent is a chlorine-free and sulfur-free organic borate ester;

[0011] The nanofunctional agent is selected from one or more of MXene (Ti3C2Tx), surface-hydroxylated modified nanodiamond, and tungsten disulfide nanosheets.

[0012] Specifically, the particle size range of the nanofunctional agent is 20-100 nm.

[0013] Specifically, the surfactant is a Gemini-type cationic surfactant or a Gemini-type nonionic surfactant.

[0014] Specifically, the corrosion inhibitor is a compound of rare earth cerium salt and benzotriazole, with a mass ratio of 1:1 to 2:1.

[0015] Specifically, the pH stabilizer is a composite system of triethanolamine and boric acid.

[0016] A method for preparing a biomimetic self-healing nanocomposite cutting fluid includes the following steps:

[0017] a) Premixing: The synthetic ester in the lubricant is mixed with all of the nanofunctional agents and mechanically stirred to form a uniform nano slurry;

[0018] b) Aqueous phase preparation: Add some deionized water to the reactor, then add surfactant, pH stabilizer and corrosion inhibitor in sequence, and stir until completely dissolved to obtain an aqueous phase solution;

[0019] c) Nano-dispersion: The nano-slurry obtained in step a is added to the aqueous solution in step b under stirring, and then subjected to high-speed shear dispersion, ultrasonic treatment and high-pressure homogenization in sequence.

[0020] d) Post-mixing: Add the remaining modified vegetable oil, extreme pressure anti-wear agent, defoamer and preservative to the homogenized liquid obtained in step c, and stir to mix evenly;

[0021] e) Maturation and filtration: After standing and maturing, the cutting fluid is obtained by filtration through a precision filter.

[0022] Specifically, in step c, the high-speed shear dispersion rotation speed is 2500-3500 rpm, and the time is 20-40 minutes; the ultrasonic treatment power is 500-1000W, and the time is 15-30 minutes; the high-pressure homogenization treatment pressure is 800-1200 bar, and the cycle is 2-5 times.

[0023] Specifically, the curing time in step e is 20-28 hours, and the pore size of the precision filter is 1-5 μm.

[0024] Application of biomimetic self-healing nanocomposite cutting fluid in precision machining of stainless steel materials.

[0025] The beneficial effects of this invention are as follows: This invention provides a biomimetic self-healing nanocomposite cutting fluid and its preparation method. This invention creatively introduces nanofunctional agents such as MXene and nanodiamond. These nanomaterials can form a high-strength, low-friction penetrating layer and repair film on the tool surface. During the cutting process, they can act like "intelligent filler materials," actively filling the microscopic defects caused by tool wear, thereby achieving a "self-healing" effect. This characteristic can significantly reduce the coefficient of friction and cutting force between the tool and the workpiece, and tests have shown that it can extend tool life by more than 50%.

[0026] Through the synergistic effect of nanofunctional agents and chlorine- and sulfur-free organic borate ester extreme pressure anti-wear agents, a robust iron boride and carbon-based composite protective film can be formed on the tool and workpiece surfaces under the high temperature and high pressure environment of the cutting zone. This protective film effectively prevents work hardening of stainless steel and material sticking to the tool, thereby achieving higher machining accuracy and better workpiece surface finish.

[0027] The formulation system of this invention completely eliminates substances such as sulfur and chlorine that are harmful to the environment and human health, reducing pollution at the source. The modified vegetable oils and other components in the formulation have better biodegradability, further reducing environmental impact.

[0028] This invention employs a unique step-by-step dispersion process of "premixing-high-speed shearing-ultrasonic activation-high-pressure homogenization." This composite process effectively solves the problem of nanoparticle aggregation in the liquid phase, ensuring the long-term and stable dispersion of nanofunctional agents in the cutting fluid system. The resulting product exhibits good storage stability, showing no sedimentation or stratification after more than 12 months, guaranteeing the consistency of product performance. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Figure 1 This is a flowchart of the present invention; Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0032] Figure 1 This is a flowchart of the present invention.

[0033] A biomimetic self-healing nanocomposite cutting fluid is composed of the following components by mass percentage: 5-10% lubricant, 2-5% extreme pressure anti-wear agent, 0.1-2% nanofunctional agent, 1-3% surfactant, 1-2% corrosion inhibitor, 0.5-1.5% pH stabilizer, 0.1-0.5% defoamer, 0.1-0.5% preservative, and the remainder is deionized water;

[0034] The lubricant is a compound of modified vegetable oil and synthetic ester, with a mass ratio of 1:1 to 3:1.

[0035] The extreme pressure anti-wear agent is a chlorine-free and sulfur-free organic borate ester;

[0036] The nanofunctional agent is selected from one or more of MXene (Ti3C2Tx), surface-hydroxylated modified nanodiamond, and tungsten disulfide nanosheets.

[0037] The particle size range of the nanofunctional agents is 20-100 nm.

[0038] During the use of cutting fluid, a lubrication system containing nanofunctional agents is delivered to the contact area where the tool and workpiece experience intense friction. Due to the extremely small size of nanomaterials (20-100 nm), they can penetrate into microscopic defects on the tool surface (such as microcracks, pores, and scratches caused by wear) thanks to their huge specific surface area and surface energy. Nanomaterials, especially surface-hydroxylated modified nanodiamonds and MXene (Ti3C2Tx), have abundant functional groups (such as -OH, -O, -F, etc.) on their surfaces. These functional groups can interact strongly with the tool (usually a metal material) surface through physical adsorption and chemical bonding, thus firmly anchoring them at the defects. This step is the basis for the formation of a stable repair film. Under the extreme conditions of high temperature and high pressure generated during the cutting process, the nanoparticles are further "compacted" into the interior of the defects under the action of friction. Like "smart filler materials," they accumulate and fill layer by layer, effectively repairing the microscopic damage to the tool and restoring the geometric integrity and smoothness of the tool's cutting edge area. This process effectively inhibits the propagation of microcracks, preventing tool chipping or breakage. As the process continues, these nanomaterials not only fill the defects but also form a high-strength, low-shear-strength solid lubricating repair film on the entire tool-workpiece contact surface.

[0039] The surfactant is a Gemini-type cationic surfactant or a Gemini-type nonionic surfactant.

[0040] The corrosion inhibitor is a compound of rare earth cerium salt and benzotriazole, with a mass ratio of 1:1 to 2:1.

[0041] The pH stabilizer is a composite system of triethanolamine and boric acid.

[0042] A method for preparing a biomimetic self-healing nanocomposite cutting fluid includes the following steps:

[0043] a) Premixing: The synthetic ester in the lubricant is mixed with all of the nanofunctional agents and mechanically stirred to form a uniform nano slurry;

[0044] b) Aqueous phase preparation: Add some deionized water to the reactor, then add surfactant, pH stabilizer and corrosion inhibitor in sequence, and stir until completely dissolved to obtain an aqueous phase solution;

[0045] c) Nano-dispersion: The nano-slurry obtained in step a is added to the aqueous solution in step b under stirring, and then subjected to high-speed shear dispersion, ultrasonic treatment and high-pressure homogenization in sequence.

[0046] d) Post-mixing: Add the remaining modified vegetable oil, extreme pressure anti-wear agent, defoamer and preservative to the homogenized liquid obtained in step c, and stir to mix evenly;

[0047] e) Maturation and filtration: After standing and maturing, the cutting fluid is obtained by filtration through a precision filter.

[0048] In step c, the high-speed shear dispersion is performed at a rotation speed of 2500-3500 rpm for 20-40 minutes; the ultrasonic treatment is performed at a power of 500-1000 W for 15-30 minutes; and the high-pressure homogenization treatment is performed at a pressure of 800-1200 bar for 2-5 cycles.

[0049] The curing time in step e is 20-28 hours, and the pore size of the precision filter is 1-5 μm.

[0050] Application of biomimetic self-healing nanocomposite cutting fluid in precision machining of stainless steel materials.

[0051] Example 1, Formulation (by weight percentage): Lubricant: 8% (of which, modified

[0052] The composition includes: 4% rapeseed oil, 4% synthetic esters, 3% extreme pressure anti-wear agent (organoboronic acid ester), 0.8% nanofunctional agent (MXene nanosheets, 50nm particle size), 2% surfactant (Gemini type nonionic surfactant), 1.5% corrosion inhibitor (including 0.8% cerium nitrate and 0.7% benzotriazole), 1.3% pH stabilizer (including 1% triethanolamine and 0.3% boric acid), 0.2% defoamer (polyether type defoamer), 0.2% preservative (isothiazolinone preservative), and the balance being deionized water. Preparation method:

[0053] 1. Premixing: In a mixing container, mix all the synthetic ester (4%) and all the MXene nanosheets (0.8%) from the formulation. Stir mechanically at 500 rpm for 30 minutes to form a uniform nano-slurry. 2. Aqueous Phase Preparation: Add deionized water (60% of the total volume) to the main reactor. Then, add Gemini surfactant, triethanolamine, boric acid, cerium nitrate, and benzotriazole sequentially. Stir at 400 rpm for approximately 20 minutes until all components are completely dissolved, resulting in a clear aqueous solution. 3. Primary Dispersion: Slowly add the nano-slurry obtained in step 1 to the aqueous solution from step 2 while stirring at 300 rpm. After addition, rapidly increase the stirring speed to 3000 rpm for high-speed shear dispersion for 30 minutes. 4. Activation: Transfer the mixture obtained in step 3 to an ultrasonic dispersion device and sonicate at 800W for 20 minutes to further break up the soft agglomeration of nanoparticles. 5. High-Pressure Homogenization: The liquid obtained in step 4 is homogenized three times using a high-pressure homogenizer at 1000 bar to obtain a nano-dispersion with uniform and stable particle size distribution. 6. Post-Formulation: The homogenized liquid obtained in step 5 is returned to the reactor. While stirring at 600 rpm, the remaining modified rapeseed oil, organoboroester, polyether defoamer, isothiazolinone preservative, and remaining deionized water are added sequentially. After addition, stirring continues for 40 minutes to ensure uniform mixing. 7. Maturation and Filtration: The formulated cutting fluid is allowed to mature for 24 hours. Finally, it is filtered through a 3μm precision filter to obtain the final biomimetic self-healing nanocomposite cutting fluid product.

[0054] Example 2 differs from Example 1 in that the nanofunctional agent is replaced with an equal amount of surface-hydroxylated nanodiamond (30 nm particle size) instead of 0.8% MXene nanosheets. The preparation method is the same as in Example 1.

[0055] Example 3 differs from Example 1 in that the composition of the nanofunctional agent is adjusted to: 0.3% MXene nanosheets and 0.5% tungsten disulfide nanosheets. The preparation method is the same as in Example 1.

[0056] Comparative Example 1 uses a certain existing stainless steel cutting fluid containing chlorine extreme pressure additives as a comparison. Performance testing: The products obtained in Examples 1-3 and the product of Comparative Example 1 were diluted to prepare 5% water-based cutting fluids, and the following performance tests were conducted. The results are summarized in the table below:

[0057] Test Project Example 1 Example 2 Example 3 Comparative Example 1 PB value (N) 980 950 965 820 Tool life (number of parts machined when VB=0.2mm) 320 305 315 180 Rust prevention (single sheet, 24h) Rust-free Rust-free Rust-free Slight rust COD removal rate after waste liquid treatment / / / <10% (after demulsification)

[0058] Test Results Analysis: As shown in the table above, the cutting fluids prepared in Examples 1-3 of this invention are significantly superior to Comparative Example 1, a traditional chlorine-containing product, in terms of extreme pressure lubrication (PB value) and tool protection capability (number of machined parts). Simultaneously, the products exhibit good rust prevention and storage stability, fully achieving the design objectives of this invention.

[0059] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A biomimetic self-healing nanocomposite cutting fluid, characterized in that, It consists of the following components by weight percentage: 5-10% lubricant, 2-5% extreme pressure anti-wear agent, 0.1-2% nano-functional agent, 1-3% surfactant, 1-2% corrosion inhibitor, 0.5-1.5% pH stabilizer, 0.1-0.5% defoamer, 0.1-0.5% preservative, and the remainder is deionized water; The lubricant is a compound of modified vegetable oil and synthetic ester, with a compounding mass ratio of 1:1 to 3:1; The extreme pressure anti-wear agent is a chlorine-free and sulfur-free organic borate ester; The nanofunctional agent is selected from one or more of MXene (Ti3C2Tx), surface-hydroxylated modified nanodiamond, and tungsten disulfide nanosheets.

2. The biomimetic self-healing nanocomposite cutting fluid according to claim 1, characterized in that: The particle size range of the nanofunctional agent is 20-100 nm.

3. The biomimetic self-healing nanocomposite cutting fluid according to claim 1, characterized in that: The surfactant is a Gemini-type cationic surfactant or a Gemini-type nonionic surfactant.

4. The biomimetic self-healing nanocomposite cutting fluid according to claim 1, characterized in that: The corrosion inhibitor is a compound of rare earth cerium salt and benzotriazole, with a mass ratio of 1:1 to 2:

1.

5. The biomimetic self-healing nanocomposite cutting fluid according to claim 1, characterized in that: The pH stabilizer is a composite system of triethanolamine and boric acid.

6. A method for preparing a biomimetic self-healing nanocomposite cutting fluid as described in any one of claims 1-5, characterized in that: Includes the following steps: a) Premixing: The synthetic ester in the lubricant is mixed with all of the nanofunctional agents and mechanically stirred to form a uniform nano slurry; b) Aqueous phase preparation: Add some deionized water to the reactor, then add surfactant, pH stabilizer and corrosion inhibitor in sequence, and stir until completely dissolved to obtain an aqueous phase solution; c) Nano-dispersion: The nano-slurry obtained in step a is added to the aqueous solution in step b under stirring, and then subjected to high-speed shear dispersion, ultrasonic treatment and high-pressure homogenization in sequence. d) Post-mixing: Add the remaining modified vegetable oil, extreme pressure anti-wear agent, defoamer and preservative to the homogenized liquid obtained in step c, and stir to mix evenly; e) Maturation and filtration: After standing and maturing, the cutting fluid is obtained by filtration through a precision filter.

7. The preparation method of the biomimetic self-healing nanocomposite cutting fluid according to claim 6, characterized in that: In step c, the high-speed shear dispersion is performed at a rotation speed of 2500-3500 rpm for 20-40 minutes; the ultrasonic treatment is performed at a power of 500-1000 W for 15-30 minutes; and the high-pressure homogenization treatment is performed at a pressure of 800-1200 bar for 2-5 cycles.

8. The preparation method of the biomimetic self-healing nanocomposite cutting fluid according to claim 6, characterized in that: The curing time in step e is 20-28 hours, and the pore size of the precision filter is 1-5 μm.

9. The application of the biomimetic self-healing nanocomposite cutting fluid according to any one of claims 1-5 in the precision machining of stainless steel materials.

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