Electric energy autonomous regulation and control method based on carbon nanotube nanometer microfluff structure

Abstract

The invention discloses an electric energy autonomous regulation and control method based on a carbon nanotube nanometer micro-villus structure, is used for improving the mass transfer efficiency in the micro electrochemical machining process, and belongs to the field of electric energy conversion control. According to the method, a nano micro-fluff structure is constructed on the surface of a carbon nanotube fiber, and dynamic adjustment of a local electric field is realized in combination with a nanosecond pulse power supply, so that the self-adaptive regulation and control capability of the electric energy of an electrode is endowed. By means of the structure, the problem of loss of a traditional electrode in electrolytic machining is solved, the mass transfer efficiency is greatly improved, and meanwhile the machining efficiency and the surface quality are improved. In specific application, the tool electrode moves along a preset path, electric energy temporary storage and release are achieved on a micro-scale interface through the nanometer micro-fluff, and positive and negative polarity nanosecond pulse power supplies are matched for alternate driving, so that ion adsorption and repulsion are periodically achieved on the surface of the electrode, and electrolyte updating and product desorption are effectively promoted. According to the method, the micro-area mass transfer rate and the machining stability are remarkably improved, and the method is suitable for electrochemical machining of metal glass, titanium alloy, shape memory alloy, metal-based composite materials and other difficult-to-machine materials which are prone to generating a large number of insoluble electrolytic products in the electrochemical machining process.

Description

Technical Field

[0001] The present invention belongs to the field of electric energy conversion control, and particularly provides a method for autonomous regulation of electric energy based on a carbon nanotube nano-microvillus structure, which is used to achieve adaptive regulation of current in micro-electrolytic machining and improve the precision machining performance of complex materials. This method is applied to the precision machining of new high-performance materials, especially suitable for micro-machining of difficult-to-machine alloys, superhard materials and new composite materials, and has strong industrial application potential, especially in the fields of microelectronics, aerospace and medical devices. Background Art

[0002] With the progress of material science, the application fields of new high-performance materials are constantly expanding. Especially in aerospace, biomedical materials and high-end equipment manufacturing, materials are required to have excellent properties such as high strength, high temperature resistance and corrosion resistance. However, the complexity and machining accuracy problems of these materials in micro-electrolytic machining are still the technical bottlenecks faced by the industry. For example, difficult-to-machine materials such as titanium alloys, ceramic materials and metallic glasses have problems such as low machining accuracy, adhesion of electrolysis products and fast electrode consumption in traditional electrolytic machining, resulting in the machining effect not meeting the design requirements.

[0003] Existing electrolytic machining technologies mainly rely on conventional electrode materials such as tungsten wire electrodes and graphite electrodes. Although a certain degree of machining can be achieved, due to the accumulation of electrolysis products, electrode corrosion during the dissolution process and low mass transfer efficiency, the machining efficiency is low and the surface quality is poor. This technology not only faces challenges in the high-precision field, but also limits its application scope in the machining of new materials.

[0004] As an advanced nanomaterial, carbon nanotubes (CNTs) have been widely used in the electrochemical field in recent years due to their excellent electrical conductivity, mechanical properties and chemical stability. However, traditional carbon nanotube electrodes still have some deficiencies. For example, under high-density current conditions, they are easily affected by problems such as the accumulation of electrolysis products and limited ion diffusion. Therefore, there is an urgent need for a new type of electrode and regulation method that can not only improve the efficiency of electrolytic machining but also ensure high machining precision.

[0005] In the patent "A method for micro-electrolytic wire cutting machining with differential synchronous fluctuation of wire electrode and workpiece" (Application No. CN119115114A, applicant Henan Institute of Technology, inventors Bi Xiaolei, Li Xuemin, Fu Ning), a machining method is designed in which the wire electrode and the workpiece swing continuously up and down synchronously and obliquely, so that the machining products are washed out by the electrolyte along the opposite direction of the synchronous fluctuation. In comparison, the present invention uses a carbon nanotube microvillus electrode and combines a nanosecond-level pulse power supply to achieve dynamic regulation of the local electric field, thereby endowing the microvillus electrode with the ability of self-adaptive regulation of electric energy.

[0006] In the patent "Ion Diffusion Control Method for Micro Electrochemical Machining of Amorphous Alloys Containing Active Metal Components" (Application No. CN117817059A, Applicant Nanjing Vocational University of Industry Technology, Inventors Hang Yusen, Wu Xiujuan, Yang Tao), a method for controlling ion diffusion in the micro electrochemical machining of amorphous alloys containing active metal components is provided. By using the mixed control polarization characteristics of charge migration and diffusion of amorphous alloys containing active metal components in non-aqueous solvent electrolytes, the ion diffusion rate is reduced. In contrast, the present invention combines the construction of a micro-villus structure on the surface of a carbon nanotube helical electrode with a nanosecond pulsed power supply, endowing the micro-villus electrode with the ability to adaptively regulate electrical energy, and solving the problems of electrode loss and adhesion of electrolysis products in pulsed electrochemical machining. Summary of the Invention

[0007] The present invention aims to solve the above technical problems at least to a certain extent, and provides a method for autonomous regulation of electrical energy based on a carbon nanotube nano-microvillus structure, which solves the loss problem of traditional electrodes in electrochemical machining, greatly enhances the mass transfer efficiency, and improves the machining efficiency and surface quality at the same time. This method has broad application prospects and can be extended to the micro machining field of other difficult-to-machine materials.

[0008] Technical Solution

[0009] To achieve the above object, the present invention provides the following technical solution: A carbon nanotube microvillus electrode, characterized in that the selected wire electrode material is a hydrophilic helical carbon nanotube fiber with a diameter of about 30 μm. The surface of the fiber forms a microvillus structure with a height of 100 - 500 nm and uniform distribution through controlling the deposition process, so as to significantly increase the specific surface area and electrical energy storage capacity of the electrode surface.

[0010] For the same purpose, the second aspect of the present invention also provides a method for autonomous regulation of electrical energy based on a carbon nanotube nano-microvillus structure, characterized by including the following processes:

[0011] Step 1: Fabricate a carbon nanotube microvillus electrode. Immerse the hydrophilic helical carbon nanotube (9) in a 1 mol / L HNO3 solution (3) diluted, and perform ultrasonic treatment for 15 minutes to activate the surface defect sites. Rinse the hydrophilic helical carbon nanotube (9) thoroughly with deionized water (4), and place it in a drying oven (5) at 60 °C for drying. Immerse the dried hydrophilic helical carbon nanotube (9) in a metal-carbon source composite precursor solution (6), and let it stand for adsorption for 2 hours. After adsorption is completed, take it out and place it in a drying oven (5) at 60 °C for drying for 3 hours. Place it in a tubular furnace (8) in an Ar:H2 atmosphere (7), and perform heat treatment at 700 - 800 °C for 1 hour to generate a nano-villus structure (2).

[0012] Step 2: Place the carbon nanotube microvillus electrode (1) into the electrolyte tank (18) through the electrode fixture (17). Connect the negative pole of the positive and negative pulse power supply (13) to the carbon nanotube microvillus electrode (1). Clamp the workpiece with the workpiece fixture (11) and place it in the electrolyte, and connect the positive pole of the positive and negative pulse power supply (13) to the workpiece (10).

[0013] Step 3: Set the processing parameters and path on the PC (16). Design the processing path and parameters on the PC (16) according to the material and shape to be processed. Use the multi-axis control platform (14) to drive the carbon nanotube microvillus electrode (1). This platform can achieve precise forward, backward, left, right, and up and down movements in space to ensure that the electrode can be positioned and operated with high precision in all directions.

[0014] Step 4: When the electrolyte (12) fills the electrolytic cell and submerges the microvillus electrode (1) and the workpiece (3), turn on the power supply (13) and set the potential parameters. The positive voltage amplitude (40) is 8V, the negative voltage amplitude (39) is -2V, the positive pulse time (37) is 80 ns, and the negative pulse time (38) is 60 ns. Control the up and down movement of the microvillus electrode (1) through the controller (15). During the positive nanosecond pulse duration, the anode workpiece (3) dissolves, and the generated metal ions (21) and non-metal particles (23) will move towards the surface of the cathode wire electrode. At the same time, the anions (27) in the electrolyte (12) will migrate from the surface of the carbon nanotube microvillus electrode (1) towards the workpiece surface (3). When the mass transfer efficiency in the micro-machining gap is lower than the generation rate of metal ions (21) and non-metal particles (23), the metal ions (21) and non-metal particles (23) will gradually accumulate around the carbon nanotube microvillus electrode (1) and even adhere to the surface of the carbon nanotube microvillus electrode (1). During the negative nanosecond pulse duration, the carbon nanotube microvillus electrode (1) will be converted into an anode and undergo an oxidation reaction. Through this conversion, the metal ions (21) and non-metal particles (23) in the electrolysis products will be "pushed away" from the surface of the carbon nanotube microvillus electrode (1), reducing the risk of adhesion of metal ions (21) and non-metal particles (23). At the same time, the oxygen bubbles (24) generated on the surface of the carbon nanotube microvillus electrode (1) will accelerate the detachment of the metal ions (21) and non-metal particles (23) attached to the surface of the carbon nanotube microvillus electrode (1), cleaning and purifying the carbon nanotube microvillus electrode (1). The positive and negative nanosecond pulse discharge curve (33) is the superposition of the positive nanosecond pulse discharge curve (36) and the negative nanosecond pulse discharge curve (32). The positive and negative nanosecond pulse discharge curve (33) drops to zero faster than the single positive nanosecond pulse discharge curve (36), and then continues to increase in the reverse direction. The negative nanosecond pulse accelerates the double-layer discharge on the surface of the workpiece (10).

[0015] Step Five: During the processing, to maintain the stability of the above-mentioned processing, it is necessary to continuously monitor the processing effect and processing parameters, and make adjustments as needed to ensure the processing quality and accuracy.

[0016] Step Six: When the processing reaches the predetermined position or shape, stop the machine. Check the processing results and perform subsequent cleaning and handling.

[0017] Preferably, the electrolyte is a 0.05 - 0.1 M NaCl ethylene glycol solution, and the electrolyte temperature is 20 - 25 °C.

[0018] Preferably, the amplitude of the reciprocating wire movement of the carbon nanotube energy storage electrode is 50 - 60 μm, and the reciprocating wire movement frequency is 5 - 8 Hz.

[0019] Preferably, for the positive and negative polarity nanosecond pulse power supply, the positive polarity nanosecond pulse voltage is 8 V, the negative polarity nanosecond pulse voltage is -2 V, the pulse width is 80 ns, and the pulse period is 1 μs.

[0020] Beneficial Effects

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Improve processing efficiency: By using a carbon nanotube micro-villus electrode and a positive and negative polarity nanosecond pulse power supply, the maximum feed rate of the electrode reaches 2.0 μm / s, which is about 3 times that of the traditional tungsten wire electrode.

[0023] 2. Improve processing accuracy and surface quality: The average surface roughness of the processed surface is only 0.018 μm, the cutting width and the standard deviation of the slot width are about 17.5 μm and 0.2 μm respectively, and there is no residue of electrolytic products on the surface.

[0024] 3. Solve the problem of electrode loss: Under the action of the positive and negative polarity nanosecond pulse voltage, for the carbon nanotube micro-villus electrode, due to its higher electrochemical dissolution potential, the carbon nanotube fibers do not undergo material dissolution and the diameter does not decrease, ensuring good process stability and processing accuracy.

[0025] 4. Enhance mass transfer efficiency: The positive and negative polarity nanosecond pulses effectively reduce the solid products adhering to the surface of the wire electrode, significantly improve the mass transfer efficiency in the micro-processing gap, reduce the concentration polarization, and improve the processing stability. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the carbon nanotube micro-villus electrode of the present invention;

[0027] Figure 2 It is a flowchart for the preparation of the carbon nanotube micro-villus electrode;

[0028] Figure 3 This is a schematic structural diagram of an apparatus for implementing an autonomous electric energy regulation method based on a carbon nanotube nano-microvillus structure in the present invention;

[0029] Figure 4 This is a schematic diagram of autonomous regulation of positive-polarity nanosecond pulse electric energy;

[0030] Figure 5 This is a schematic diagram of autonomous regulation of negative-polarity nanosecond pulse electric energy;

[0031] Figure 6 This is a schematic diagram of the charge exchange process of the electric double layer during the alternation of positive and negative nanosecond pulses;

[0032] Figure 7 This is a waveform diagram of positive and negative polarity nanosecond pulse power supplies;

[0033] Figure 8 This is a comparison diagram of the processing effects of positive-polarity nanosecond pulses and positive and negative polarity nanosecond pulses.

[0034] In the figure: 1. Carbon nanotube microvillus electrode, 2. Microvillus structure, 3. HNO3 solution, 4. Deionized water, 5. Drying oven, 6. Metal-carbon source composite precursor solution, 7. Tube furnace, 8. Ar:H2 atmosphere (9:1), 9. Hydrophilic helical carbon nanotubes, 10. Workpiece, 11. Workpiece fixture, 12. Electrolyte, 13. Positive and negative polarity nanosecond pulse power supply, 14. Three-axis moving platform, 15. Controller, 16. PC, 17. Electrode fixture, 18. Electrolyte tank, 19. Power switch, 20. Hydrogen bubbles, 21. Metal cations, 22. Movement direction of metal cations in the positive-polarity stage, 23. Non-metal ions, 24. Oxygen bubbles, 25. Positive-polarity state of the workpiece, 26. Metal cation non-metal ion group, 27. Electrons, 28. Movement direction of electrons in the positive-polarity stage, 29. Negative-polarity state of the electrode, 30. Negative-polarity state of the workpiece, 31. Positive-polarity state of the electrode, 32. Discharge curve of negative-polarity nanosecond pulse, 33. Discharge curve of positive and negative polarity nanosecond pulses, 34. Amplitude of negative-polarity nanosecond pulse, 35. Amplitude of positive-polarity nanosecond pulse, 36. Discharge curve of positive-polarity nanosecond pulse, 37. Time of positive-polarity nanosecond pulse, 38. Time of negative-polarity nanosecond pulse, 39. Amplitude of negative-polarity nanosecond pulse, 40. Assignment of positive-polarity nanosecond pulse, 41. Surface of the pulse power supply electrode, 42. Surface of the positive and negative polarity nanosecond pulse power supply electrode, 43. Electrolytic products adhering to the electrode surface.

[0035] Conclusion

[0036] The present invention is based on a method for autonomous regulation of electrical energy based on a carbon nanotube nano-microvillus structure. By optimizing the electrode material and charge regulation mechanism, the problem of loss of traditional electrodes in electrochemical machining is solved, the mass transfer efficiency is greatly enhanced, and at the same time, the machining efficiency and surface quality are improved. This method has broad application prospects and can be extended to the field of micro-electrochemical machining of other difficult-to-machine materials. Detailed implementation mode

[0037] To make the objectives, technical solutions and advantages of the present invention clearer, the following will further describe the implementation modes of the present invention in detail with reference to the accompanying drawings.

[0038] Example 1:

[0039] Refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 . A method for autonomous regulation of electrical energy of a carbon nanotube microvillus electrode includes the following steps:

[0040] Step 1: Fabricate a carbon nanotube microvillus electrode. Immerse the hydrophilic helical carbon nanotubes (9) in a diluted 1 mol / L HNO3 solution (3) and ultrasonically treat for 15 minutes to activate the surface defect sites. Thoroughly rinse the hydrophilic helical carbon nanotubes (9) with deionized water (4) and dry them in a drying oven (5) at 60 °C. Immerse the dried hydrophilic helical carbon nanotubes (9) in a metal carbon source composite precursor solution (6) and let them stand for adsorption for 2 hours. After adsorption is completed, take them out and dry them in a drying oven (5) at 60 °C for 3 hours. Place them in a tube furnace (8) in an Ar:H2 atmosphere (7) and heat-treat at 700 - 800 °C for 1 hour to form a nano-microvillus structure (2).

[0041] Step 2: Place the carbon nanotube microvillus electrode (1) in the electrolyte tank (18) through the electrode fixture (17). Connect the negative electrode of the positive and negative nanosecond pulse power supply (13) to the carbon nanotube microvillus electrode (1). Clamp the workpiece with the workpiece fixture (11) and place it in the electrolyte, and connect the positive electrode of the positive and negative nanosecond pulse power supply (13) to the workpiece (10).

[0042] Step 3: Set the machining parameters and path on the PC (16). According to the material and shape to be machined, design the machining path and machining parameters on the PC (16). Use a multi-axis control platform (14) to drive the carbon nanotube microvillus electrode (1), and this platform can achieve precise movement in the front-back, left-right, and up-down directions in space to ensure that the electrode can be positioned and operated with high precision in all directions.

[0043] Step 4: When the electrolyte (12) fills the electrolytic cell and submerges the microvillus electrode (1) and the workpiece (3), turn on the power supply (13) and set the potential parameters. The positive voltage amplitude (40) is 8V, the negative voltage amplitude (39) is -2V, the positive nanosecond pulse time (37) is 80ns, and the negative nanosecond pulse time (38) is 60ns. Control the up and down movement of the microvillus electrode (1) through the controller (15). During the positive nanosecond pulse duration, the anode workpiece (3) dissolves, and the generated metal ions (21) and non-metal particles (23) will move towards the surface of the cathode wire electrode. At the same time, the anions (27) in the electrolyte (12) will migrate from the surface of the carbon nanotube microvillus electrode (1) towards the surface of the workpiece (3). When the mass transfer efficiency in the micro-machining gap is lower than the generation rate of metal ions (21) and non-metal particles (23), the metal ions (21) and non-metal particles (23) will gradually accumulate around the carbon nanotube microvillus electrode (1) and even adhere to the surface of the carbon nanotube microvillus electrode (1). During the negative nanosecond pulse duration, the carbon nanotube microvillus electrode (1) will be converted into an anode and undergo an oxidation reaction. Through this conversion, the metal ions (21) and non-metal particles (23) in the electrolysis products will be "pushed away" from the surface of the carbon nanotube microvillus electrode (1), reducing the risk of adhesion of metal ions (21) and non-metal particles (23). At the same time, the oxygen bubbles (24) generated on the surface of the carbon nanotube microvillus electrode (1) will accelerate the detachment of the metal ions (21) and non-metal particles (23) attached to the surface of the carbon nanotube microvillus electrode (1), cleaning and purifying the carbon nanotube microvillus electrode (1).

[0044] Step 5: During the machining process, to maintain the stability of the above machining, it is necessary to continuously monitor the machining effect and machining parameters and adjust them as needed to ensure the machining quality and accuracy.

[0045] Step 6: When the machining reaches the predetermined position or shape, stop the machine. Check the machining results and perform subsequent cleaning and processing.

[0046] Example 2:

[0047] To illustrate the beneficial effects of the present invention, a positive pulse power supply is used instead of the above-mentioned positive and negative nanosecond pulse power supply, including the following steps:

[0048] Step 1: The same as Step 1 of Example 1;

[0049] Step 2: The same as Step 2 of Example 1;

[0050] Step 3: The same as Step 3 of Example 1;

[0051] Step 4: When the electrolyte (12) fills the electrolytic cell to submerge the microvillus electrode (1) and the workpiece (3), turn on the pulse power supply and set the potential parameters. The pulse voltage amplitude is 8 V, the pulse time is 80 ns, and the controller (15) is used to control the up and down movement of the microvillus electrode (1).

[0052] Step 5: The same as Step 5 of Embodiment 1;

[0053] Step 6: The same as Step 6 of Embodiment 1;

[0054] It is found through experiments that obvious residual products (43) exist on the surface (41) of the electrode using the positive-polarity pulse power supply. Compared with the positive-polarity pulse power supply, the surface quality of the electrode (42) is significantly improved when using the above positive and negative polarity nanosecond pulse power supply, and there is no obvious adhesion of electrolytic products.

[0055] Matters not covered by this invention are well-known technologies.

[0056] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It is not intended to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. An autonomous power regulation method based on a carbon nanotube nano-microvillus structure, characterized in that: The surface of the carbon nanotube microvillus electrode (1) has a specially customized microvillus structure (2), and the height of the microvillus structure is 100 - 500 nm, which is evenly distributed on the surface of the carbon nanotube fiber.

2. The carbon nanotube microvillus electrode described in claim 1 uses a hydrophilic helical carbon nanotube fiber with a diameter of 30 μm and is functionalized by metal electrodeposition and dynamic liquid film electrochemical anodization methods.

3. The microvillus structure (2) on the main surface of the carbon nanotube microvillus electrode (1) described in claim 1 has the functions of electric energy storage and electric energy release.

4. An autonomous electric energy regulation method based on a carbon nanotube nano-microvillus structure, characterized in that, It includes the following steps: Step 1: Fabricate the carbon nanotube microvillus electrode (1). Step 2: Place the carbon nanotube microvillus electrode (1) in the electrolyte tank (18) through the electrode fixture (17). Connect the negative pole of the positive and negative pulse power supply (13) to the carbon nanotube microvillus electrode (1). Clamp the workpiece (10) with the workpiece fixture (11) and place it in the electrolyte (12), and connect the positive pole of the positive and negative pulse power supply (13) to the workpiece (10). Step 3: Set and design the processing parameters and paths for the carbon nanotube microvillus electrode (1) through the PC (16). At the same time, turn on the positive and negative nanosecond pulse power supply (13) to set the potential parameters, alternately generate positive nanosecond pulses and negative nanosecond pulses, and start processing. Step 4: Stop processing when the processing reaches the predetermined position.

5. The method for autonomous regulation of electric energy based on a carbon nanotube nano-microvillus structure according to claim 4, characterized in that: During the duration of the positive nanosecond pulse, the anode workpiece (3) dissolves, and the generated metal ions (21) and non-metal particles (23) will move towards the surface of the cathode wire electrode. At the same time, the anions (27) in the electrolyte (12) will migrate from the surface of the carbon nanotube microvillus electrode (1) towards the surface of the workpiece (3). When the mass transfer efficiency in the micro-machining gap is lower than the generation rate of metal ions (21) and non-metal particles (23), the metal ions (21) and non-metal particles (23) will gradually accumulate around the carbon nanotube microvillus electrode (1) and even adhere to the surface of the carbon nanotube microvillus electrode (1).

6. The power self-regulation method based on a carbon nanotube nano-microvillus structure according to claim 4, characterized in that: During the duration of the negative nanosecond pulse, the carbon nanotube microvillus electrode (1) will be converted into an anode and undergo an oxidation reaction. Through this conversion, the metal ions (21) and non-metal particles (23) in the electrolysis products will be "pushed away" from the surface of the carbon nanotube microvillus electrode (1), reducing the adhesion risk of metal ions (21) and non-metal particles (23). At the same time, the oxygen bubbles (24) generated on the surface of the carbon nanotube microvillus electrode (1) will accelerate the detachment of the metal ions (21) and non-metal particles (23) attached to the surface of the carbon nanotube microvillus electrode (1), cleaning and purifying the carbon nanotube microvillus electrode (1).

7. A method for autonomous regulation of electric energy based on a carbon nanotube nano-microvillus structure according to claim 4, characterized in that: Drive the carbon nanotube microvillus electrode (1) using a multi-axis control platform (14), which can achieve precise forward, backward, left, right, and up and down movements in space to ensure that the electrode can be accurately positioned and operated in all directions.

8. A method for autonomous regulation of electric energy based on a carbon nanotube nano-microvillus structure according to claim 4, characterized in that: The method is applicable to the electrolytic machining of difficult-to-machine materials such as metallic glasses, titanium alloys, shape memory alloys, and metal matrix composites that are prone to generating a large amount of insoluble electrolytic products during electrochemical machining.

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