Black phosphorus-hydrotalcite composite material additive for cold rolling emulsion and application thereof

Abstract

This invention discloses a black phosphorus-hydrotalcite composite material additive for cold rolling emulsions and its application. The preparation method of the black phosphorus-hydrotalcite composite material additive for cold rolling emulsions involves mixing black phosphorus nanosheets, MgAl-LDH, stearic acid, and anhydrous ethanol in a specific mass ratio, followed by ultrasonic dispersion. The mixture is then stirred and reacted at 20-40°C for 2-3 hours. The supernatant is collected by centrifugation and vacuum dried at 40°C for 8 hours. The mass ratio of black phosphorus nanosheets, MgAl-LDH, and stearic acid is 1:2-5:1-3, and the mass-to-volume ratio of black phosphorus nanosheets to anhydrous ethanol is 2:3-5 mg / ml. The additive provided by this invention uses black phosphorus and hydrotalcite as core components, contains no harmful chemical substances, and is suitable for cold rolling processes of difficult-to-machine metals. It meets the lubrication requirements of high-strength processing while reducing waste liquid treatment costs. The friction coefficient of the emulsion with the additive of this invention is stable between 0.082 and 0.12, which can effectively solve problems such as adhesion and surface scratches in the cold rolling of difficult-to-process metals, and improve the processing accuracy of the sheet and the service life of the rolls.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating materials, and particularly relates to a black phosphorus-hydrotalcite composite additive for cold rolling emulsion and its application. Background Art

[0002] Cold rolling, as an important process for precision forming of metal materials, is widely used in fields such as aerospace, automotive manufacturing, and electronic information. Its processing quality has an important impact on the dimensional accuracy, surface quality, and mechanical properties of the sheet. During cold rolling, the emulsion serves as a key process medium and needs to simultaneously perform the functions of lubrication, cooling, and maintaining system stability: good lubrication helps reduce the friction between the roll and the sheet and minimize wear; effective cooling can promptly remove the heat generated during rolling to prevent overheating and deformation of the workpiece and the roll; and system stability is related to whether the emulsion can maintain a uniform state during recycling to avoid demulsification or stratification, thus ensuring the continuity and stability of the production process. Therefore, an emulsion with excellent lubricity, cooling property, and stability is one of the important conditions for achieving efficient and high-precision cold rolling.

[0003] However, the emulsion technology currently used in industry still faces certain limitations, mainly reflected in the difficulty of balancing lubrication performance and emulsion stability. To improve the lubrication effect, specific lubricating additives are usually added, but the addition of these additives easily affects the colloidal stability of the emulsion, which may lead to demulsification or stratification and interfere with normal production; if the dosage of the additives is controlled to maintain stability, the lubrication performance often decreases, the friction coefficient of the emulsion is usually high, and the wear degree increases, which may cause problems such as increased roll loss and decreased surface quality of the sheet.

[0004] In addition, there are still some deficiencies in the existing lubrication systems for emulsions: traditional lubricants often rely on additives containing sulfur, phosphorus, etc. that have certain environmental impacts to improve performance. These components may remain after processing or be discharged with waste liquid, imposing a burden on the environment, and their applicability to difficult-to-process materials such as Zr-4 alloy and titanium alloy is relatively limited; on the other hand, the preparation of high-performance lubricating additives mostly involves complex synthesis processes, which require high production equipment requirements and also drive up production costs, restricting their large-scale application in the high-end cold rolling field to a certain extent. These above problems have become technical challenges that need to be concerned about and solved in the process of further improving the accuracy, reducing the environmental burden, and controlling costs in the current cold rolling process.

[0005] The present invention aims to provide a black phosphorus-hydrotalcite composite additive for cold rolling emulsion and its application. Summary of the Invention

[0006] The first objective of this invention is to provide a black phosphorus-hydrotalcite composite material additive for cold rolling emulsions, and the second objective of this invention is to provide the application of said additive.

[0007] The first objective of this invention is achieved as follows: a black phosphorus-hydrotalcite composite material additive for cold rolling emulsion is prepared by mixing black phosphorus nanosheets, MgAl-LDH, stearic acid and anhydrous ethanol in a mass ratio, ultrasonically dispersing the mixture, stirring and reacting at 20-40℃ for 2-3 hours, centrifuging to collect the supernatant, and vacuum drying at 40℃ for 8 hours. The mass ratio of black phosphorus nanosheets, MgAl-LDH and stearic acid is 1:2-5:1-3, and the mass-volume ratio of black phosphorus nanosheets to anhydrous ethanol is 2:3-5 mg / ml.

[0008] The second objective of this invention is achieved by using the additive in the preparation of cold-rolled emulsions.

[0009] The principle of this invention is as follows: Both black phosphorus and hydrotalcite have bottlenecks in emulsion applications. Although black phosphorus possesses excellent interlayer shear properties, its dispersion stability in aqueous environments is poor, it is prone to aggregation and oxidation, making it difficult to exert a long-lasting lubricating effect. Hydrotalcite, on the other hand, has a strong positive charge on its surface, which easily undergoes electrostatic neutralization with negatively charged emulsion particles, leading to early flocculation of the emulsion. Furthermore, its polar surface has poor compatibility with the organic phase, making it unsuitable for high-filling addition and limiting its barrier and stabilizing functions. The black phosphorus-hydrotalcite composite material provided by this invention overcomes the above problems through synergistic effects: the layered structure of hydrotalcite can serve as a supporting substrate for black phosphorus, inhibiting its aggregation and oxidation, and improving dispersion stability; the hydroxyl and oxygen functional groups introduced on the surface of black phosphorus through oxidation can enhance the interfacial bonding force with hydrotalcite, improving the compatibility of the composite material with the organic phase. Meanwhile, the composite material can regulate the surface charge distribution, avoid excessive neutralization with emulsion particles, ensure emulsion stability, achieve high filler addition, and thus synergistically exert the friction-reducing properties of black phosphorus and the barrier and stabilizing effects of hydrotalcite, significantly improving the overall performance of the emulsion.

[0010] The beneficial effects of this invention are as follows: 1. Significantly improved lubrication performance and superior wear control: Traditional lubricants typically have a friction coefficient that is difficult to lower than 0.2, and a high wear rate, which easily leads to roll wear and poor sheet surface quality. The emulsion with the additive of this invention can maintain a friction coefficient between 0.082 and 0.12, effectively solving problems such as adhesion and surface scratches in the cold rolling of difficult-to-machine metals, improving sheet processing accuracy and roll service life.

[0011] 2. Wide compatibility and environmentally friendly: Traditional lubricants often rely on harmful additives such as sulfur and phosphorus to improve performance, which easily causes environmental pollution and has poor compatibility with difficult-to-machine metals (such as Zr-4 alloys and titanium alloys). The additive provided by this invention uses black phosphorus and hydrotalcite as core components, without the addition of harmful chemicals, and through structural optimization, it is adapted to the cold rolling process of difficult-to-machine metals. It can not only meet the lubrication requirements of high-intensity processing, but also reduce the cost of waste liquid treatment, which is in line with the development trend of green processing.

[0012] 3. The preparation process is simple and the cost is controllable. Traditional high-performance lubricant additives often require complex chemical synthesis processes, high equipment requirements, and high production costs. This invention prepares composite materials through simple and controllable steps such as high-energy ball milling, hydrothermal synthesis, and ultrasonic electrostatic self-assembly. The raw materials are readily available (red phosphorus, magnesium chloride, aluminum nitrate, etc. are all conventional chemical raw materials), and the reaction conditions are mild, giving it a cost advantage compared to traditional high-end lubricants. Attached Figure Description

[0013] Figure 1 The black phosphorus-hydrotalcite composite materials prepared in Examples 1-3 of this invention; Figure 2 The friction curves of the emulsions containing black phosphorus-hydrotalcite composite material additives prepared in Examples 1-3 of the present invention and Comparative Examples 1-2 are shown. Figure 3 The emulsions of the black phosphorus-hydrotalcite composite material additives prepared in Examples 1-3 of the present invention and the average friction coefficient diagrams of Comparative Examples 1-2 are shown. Figure 4 Emulsions containing black phosphorus-hydrotalcite composite material additives prepared in Examples 1-3 of this invention and disc wear rate diagrams for Comparative Examples 1-2 are shown. Figure 5 Images of emulsions containing black phosphorus-hydrotalcite composite material additives prepared in Examples 1-3 of this invention and Comparative Example 3 after standing for 30 days, from left to right: Examples 1-3 and Comparative Examples 1-3. Figure 6 The emulsions containing black phosphorus-hydrotalcite composite material additives prepared in Examples 1-3 of this invention and the emulsion ratio of Comparative Example 3 after standing for 30 days are shown. Detailed Implementation

[0014] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0015] This invention discloses a black phosphorus-hydrotalcite composite material additive for cold rolling emulsions. The preparation method involves mixing black phosphorus nanosheets, MgAl-LDH, stearic acid, and anhydrous ethanol in a mass ratio, ultrasonically dispersing the mixture, stirring and reacting at 20-40℃ for 2-3 hours, centrifuging to collect the supernatant, and vacuum drying at 40℃ for 8 hours to obtain the final product. The mass ratio of black phosphorus nanosheets, MgAl-LDH, and stearic acid is 1:2-5:1-3, and the mass-volume ratio of black phosphorus nanosheets to anhydrous ethanol is 2:3-5 mg / ml.

[0016] The black phosphorus nanosheets have a particle size of 10-100 nm, and the MgAl-LDH has a particle size of 10-100 nm.

[0017] The stirring speed is 180 rpm.

[0018] The centrifugation speed is 9000 rpm.

[0019] The vacuum drying temperature is 40℃ and the drying time is 8 hours.

[0020] The present invention also provides the application of the additives described herein in the preparation of cold rolling emulsions.

[0021] The present invention further provides a cold-rolled emulsion, comprising the additive, base oil and water, wherein the mass ratio of the additive to the base oil is 1:5-10.

[0022] The cold-rolled emulsion is prepared by mixing additives, base oil and water in a certain proportion and then emulsifying them in a homogenizer at a speed of 6000-8000 r / min for 30-60 min.

[0023] Example 1 The preparation process of the black phosphorus-hydrotalcite composite material additive for emulsions in this embodiment is as follows: 1) Red phosphorus powder and stainless steel balls with diameters of 5 mm and 10 mm were mixed in a stainless steel ball mill jar. The mass ratio of red phosphorus to stainless steel balls was 1:20, the ball milling speed was 1000 r / min, and the ball milling time was 7 h. After ball milling, the product was purified and cleaned with phosphorus bromide and carbon disulfide, and then vacuum dried to obtain black phosphorus nanosheets.

[0024] 2) Add magnesium chloride hexahydrate, aluminum nitrate nonahydrate, and urea to deionized water and stir until completely dissolved. Transfer the solution to a stainless steel reactor lined with polytetrafluoroethylene (PTFE). (Mg...) 2+ Al 3+ The molar ratio of urea and deionized water is 2:1:6:2000. The mixture is subjected to hydrothermal reaction at 100℃ for 24 hours. The reactants are then centrifuged and dried to obtain MgAl-LDH powder.

[0025] 3) Add 20 mg of black phosphorus nanosheets, 40 mg of MgAl-LDH, 20 mg of stearic acid, and 30 ml of anhydrous ethanol to a 100 mL beaker, sonicate for a period of time, and stir at 180 rpm at 30 °C for 3 h. After the reaction is completed, centrifuge at 9000 rpm for 10 min, wash three times with anhydrous ethanol, and vacuum dry at 40 °C for 8 h to obtain the black phosphorus-hydrotalcite composite material.

[0026] The black phosphorus-hydrotalcite composite material additive was weighed at 0.2 wt% of the rapeseed oil mass and added to 1 ml of rapeseed oil. It was then ultrasonically dispersed to form an oil phase containing the additive. Subsequently, 5 ml of deionized water was added and emulsified using a homogenizer at 8000 r / min for 60 min to obtain an emulsion containing the black phosphorus-hydrotalcite composite material additive.

[0027] Example 2 The preparation process of the black phosphorus-hydrotalcite composite material additive for emulsions in this embodiment is as follows: 1) Red phosphorus powder and stainless steel balls with diameters of 5 mm and 10 mm were mixed in a stainless steel ball mill jar. The mass ratio of red phosphorus to stainless steel balls was 1:80, the ball milling speed was 1500 r / min, and the ball milling time was 7 h. After ball milling, the product was purified and cleaned with phosphorus bromide and carbon disulfide, and then vacuum dried to obtain black phosphorus nanosheets.

[0028] 2) Add magnesium chloride hexahydrate, aluminum nitrate nonahydrate, and urea to deionized water and stir until completely dissolved. Transfer the solution to a stainless steel reactor lined with polytetrafluoroethylene (PTFE). (Mg...) 2+ Al 3+ The molar ratio of urea and deionized water is 2:1:6:2000. The mixture is subjected to hydrothermal reaction at 100℃ for 24 hours. The reactants are then centrifuged and dried to obtain MgAl-LDH powder.

[0029] 3) Add 20 mg of black phosphorus nanosheets, 80 mg of MgAl-LDH, 40 mg of stearic acid, and 40 ml of anhydrous ethanol to a 100 mL beaker, sonicate for a period of time, and stir at 180 rpm at 30 °C for 2 h. After the reaction is completed, centrifuge at 9000 rpm for 10 min, wash three times with anhydrous ethanol, and vacuum dry at 40 °C for 8 h to obtain the black phosphorus-hydrotalcite composite material.

[0030] The black phosphorus-hydrotalcite composite material additive was weighed at 0.2 wt% of the rapeseed oil mass and added to 1 ml of rapeseed oil. It was then ultrasonically dispersed to form an oil phase containing the additive. Subsequently, 5 ml of deionized water was added and emulsified using a homogenizer at 8000 r / min for 60 min to obtain an emulsion containing the black phosphorus-hydrotalcite composite material additive.

[0031] Example 3 The preparation process of the black phosphorus-hydrotalcite composite material additive for emulsions in this embodiment is as follows: 1) Red phosphorus powder and stainless steel balls with diameters of 5 mm and 10 mm were mixed in a stainless steel ball mill jar. The mass ratio of red phosphorus to stainless steel balls was 1:60, the ball milling speed was 1200 r / min, and the ball milling time was 7 h. After ball milling, the product was purified and cleaned with phosphorus bromide and carbon disulfide, and then vacuum dried to obtain black phosphorus nanosheets.

[0032] 2) Add magnesium chloride hexahydrate, aluminum nitrate nonahydrate, and urea to deionized water and stir until completely dissolved. Transfer the solution to a stainless steel reactor lined with polytetrafluoroethylene (PTFE). (Mg...) 2+ Al 3+ The molar ratio of urea and deionized water is 2:1:6:2000. The mixture is subjected to hydrothermal reaction at 100℃ for 24 hours. The reactants are then centrifuged and dried to obtain MgAl-LDH powder.

[0033] 3) Add 20mg of black phosphorus nanosheets, 100mg of MgAl-LDH, 60mg of stearic acid, and 50ml of anhydrous ethanol to a 100mL beaker, sonicate for a period of time, and stir at 180rpm at 30℃ for 3h. After the reaction is completed, centrifuge at 9000rpm for 10min, wash three times with anhydrous ethanol, and vacuum dry at 40℃ for 8h to obtain black phosphorus-hydrotalcite composite material.

[0034] The black phosphorus-hydrotalcite composite material additive was weighed at 0.2 wt% of the rapeseed oil mass and added to 1 ml of rapeseed oil. It was then ultrasonically dispersed to form an oil phase containing the additive. Subsequently, 5 ml of deionized water was added and emulsified using a homogenizer at 8000 r / min for 60 min to obtain an emulsion containing the black phosphorus-hydrotalcite composite material additive.

[0035] Comparative Example 1 The difference between this comparative example and Comparative Example 1 is that no additives were added to prepare the emulsion (i.e., 1 ml of rapeseed oil and 5 ml of water were mixed and emulsified for 30 min at 6000 r / min using a homogenizer).

[0036] Comparative Example 2 This comparative example only added stearic acid-modified black phosphorus nanosheets to prepare an emulsion (i.e., 0.2 wt% of stearic acid-modified black phosphorus nanosheets were added to 1 ml of rapeseed oil and 5 ml of water, and emulsified using a homogenizer at 6000 r / min for 30 min). The preparation method of stearic acid-modified black phosphorus nanosheets is as follows: 20 mg of black phosphorus powder was added to 40 ml of anhydrous ethanol, placed in an ultrasonic cell disruptor, and ultrasonically disrupted for 20 minutes at 300 W power for 4 seconds with a 2-second interval. 10 mg of stearic acid was added to the above dispersion and ultrasonically disrupted for another 20 minutes. The resulting solution was placed in an argon-protected environment and magnetically stirred for 30 minutes at 400 rpm to further promote the modification of stearic acid-modified black phosphorus. Finally, the mixture was centrifuged 2-3 times, and the resulting material was placed in a vacuum drying oven at 50 °C for 6 h to obtain stearic acid-modified black phosphorus nanosheet powder.

[0037] Comparative Example 3 This comparative example only added stearic acid-modified hydrotalcite to prepare the emulsion (i.e., 0.2 wt% of stearic acid-modified hydrotalcite was added to 1 ml of rapeseed oil and 5 ml of water, and emulsified using a homogenizer at 6000 r / min for 30 min). The preparation method of stearic acid-modified hydrotalcite is as follows: 20 mg of hydrotalcite powder was added to 40 ml of anhydrous ethanol, placed in an ultrasonic cell disruptor, and ultrasonically disrupted for 20 minutes at 300 W power for 4 seconds with a 2-second interval. 10 mg of stearic acid was added to the above dispersion and ultrasonically disrupted for another 20 minutes. The resulting solution was placed in an argon-protected environment and magnetically stirred for 30 minutes at 400 rpm to further promote the modification of black phosphorus by stearic acid. Finally, the mixture was centrifuged 2-3 times, and the resulting material was placed in a vacuum drying oven at 50 °C for 6 h to obtain stearic acid-modified hydrotalcite powder.

[0038] Experimental Example 1 The emulsions prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to a 30-day static stability test.

[0039] Results: The emulsions of Comparative Examples 1-3 without any additives showed obvious stratification after standing for 30 days. Among them, the emulsion ratio of Comparative Example 1 was only 0.64; while the emulsions with added black phosphorus-hydrotalcite composite material (Examples 1-3) did not show any stratification after standing for 30 days, and the emulsion ratio was as high as 1 ( Figure 5-6 ).

[0040] Experiment Example 2 Friction and wear tests were conducted on the emulsions prepared in Examples 1-3 and Comparative Examples 1-3. An MS-T3001 friction and wear testing machine was used to evaluate the tribological properties. The fixed parameters were: load 10 N, rotation speed 100 r / min, and rotation diameter 3 mm. The friction pairs were GCr15 bearing steel balls and Zr-4 alloy disks, respectively. Before the experiment, the balls and disks were ultrasonically cleaned with petroleum ether and ethanol to ensure a smooth surface. After the samples were mounted, a small amount of emulsion was dripped onto the Zr-4 alloy disk. The machine was then started and rotated. After 30 minutes, the test was stopped, and the relevant friction coefficient curves were recorded.

[0041] The results of friction and wear tests conducted without any lubricant were used as a control. The specific experimental method is as follows: An MS-T3001 friction and wear testing machine was used to evaluate the tribological properties. The fixed parameters were: load 10N, rotation speed 100r / min, and rotation diameter 5mm. The friction pairs were GCr15 bearing steel balls and a Zr-4 alloy disc. Before the experiment, the balls and disc were ultrasonically cleaned with petroleum ether and ethanol respectively to ensure a smooth surface. After the sample was mounted, a small amount of deionized water was dripped onto the Zr-4 disc. The machine was started and rotated. After 30 minutes of testing, the test was stopped, and the relevant friction coefficient curves were recorded.

[0042] Result: As Figure 2-4 As shown, in the unlubricated dry friction and wear test of Zr-4 alloy disks, the friction coefficient was 0.411 after adding an emulsion without any additives to the test system; after adding an emulsion with stearic acid-modified black phosphorus nanosheets to the test system, the friction coefficient decreased to 0.178 (Comparative Example 2), a reduction of 56.7% compared to the emulsion condition without any additives. After adding an emulsion with stearic acid-modified black phosphorus nanosheets to the test system, the friction coefficient decreased to 0.272 (Comparative Example 3), a reduction of 33.8% compared to the emulsion condition without any additives.

[0043] When the emulsions containing the black phosphorus-hydrotalcite composite material additives from Examples 1-3 of this invention were used, the friction coefficient of the system decreased significantly. The friction coefficients of Examples 1-3 were as low as 0.120, 0.107, and 0.082, respectively, representing a reduction of 70.8–80.1% compared to dry friction conditions. Wear performance test results showed that the wear rates of Examples 1-3 were 7.91 × 10⁻⁶, respectively. -5 mm 3 / (N·m), 7.57×10 -5 mm 3 / (N·m) and 7.49×10 -5 mm 3 / (N·m), compared to dry friction conditions, the wear rate reduction is as high as 88.4–89.1% ( Figure 4 ).

[0044] In summary, the emulsion containing the black phosphorus-hydrotalcite composite material prepared according to this invention has both excellent friction reduction and wear reduction effects and emulsion stabilization ability, and can be widely used in the cold rolling process of difficult-to-machine metals.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A black phosphorus-hydrotalcite composite material additive for cold rolling emulsions, characterized in that, The preparation method involves mixing black phosphorus nanosheets, MgAl-LDH, stearic acid, and anhydrous ethanol in a mass ratio, followed by ultrasonic dispersion, stirring at 20-40℃ for 2-3 hours, centrifuging to collect the supernatant, and vacuum drying at 40℃ for 8 hours. The mass ratio of black phosphorus nanosheets, MgAl-LDH, and stearic acid is 1:2-5:1-3, and the mass-volume ratio of black phosphorus nanosheets to anhydrous ethanol is 2:3-5 mg / ml.

2. The black phosphorus-hydrotalcite composite material additive according to claim 1, characterized in that, The black phosphorus nanosheets have a particle size of 10-100 nm, and the MgAl-LDH has a particle size of 10-100 nm.

3. The black phosphorus-hydrotalcite composite material additive according to claim 1, characterized in that, The stirring speed is 180 rpm.

4. The black phosphorus-hydrotalcite composite material additive according to claim 1, characterized in that, The centrifugation speed is 9000 rpm.

5. The black phosphorus-hydrotalcite composite material additive according to claim 1, characterized in that, The vacuum drying temperature is 40℃ and the drying time is 8 hours.

6. The use of the additive according to claim 1 in the preparation of cold rolling emulsion.

7. A cold-rolled emulsion, characterized in that, It includes the additive as described in claim 1, base oil, and water, wherein the mass ratio of the additive to the base oil is 1:5-10.

8. The cold-rolling emulsion according to claim 7, characterized in that, The cold-rolled emulsion is prepared by mixing additives, base oil and water in a certain proportion and then emulsifying them in a homogenizer at a speed of 6000-8000 r / min for 30-60 min.

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