Method for dynamically regulating and controlling electrochemical polishing through energy storage electrode and application of method

Abstract

The invention provides a method for dynamically regulating and controlling electrochemical polishing through an energy storage electrode and application of the method, and relates to the technical field of electrochemical machining. According to the method, the energy storage electrode with the multi-dimensional nano array surface appearance is utilized, and directional precise polishing of the nanoscale material is achieved by precisely regulating and controlling the surface charge storage and release characteristics of the energy storage electrode. During polishing, the energy storage electrode is combined with reciprocating motion, electric charges are stored or released through feedback of potential and current density of a working solution, the potential and the current density are more simply and accurately stabilized in a passivation interval, the polishing efficiency and the surface quality are greatly improved, the polishing stability is guaranteed, and the mass transfer efficiency and discharge of polishing products are enhanced. The method is suitable for electrochemical polishing of stainless steel, titanium alloy, nickel-based alloy glass and other difficult-to-machine metal materials and amorphous alloy materials.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical machining technology, relates to electrochemical polishing technology, and specifically relates to a method for dynamically controlling electrochemical polishing by utilizing energy storage electrodes and its application. Background Art

[0002] Electrochemical polishing is a surface finishing technique based on the principle of electrochemical anodic dissolution. By applying an external electric field, it selectively dissolves the workpiece surface, reducing surface roughness and improving finish. This technique has wide applications in precision manufacturing, medical devices, aerospace, and other fields, and is particularly suitable for surface treatment of difficult-to-machine metal materials such as stainless steel, titanium alloys, nickel-based alloys, and glass.

[0003] Electrochemical polishing typically uses an acidic nano-working fluid system as an ion-conducting medium. By adjusting process parameters such as the nano-working fluid composition, temperature, current density, and polarization time, the metal material removal rate during anodic dissolution and the formation and breakdown of the surface passivation film are controlled. During electrochemical polishing, controlling the potential and current density within the passivation range is crucial for achieving high-quality polishing. Existing potential control technologies often suffer from operational difficulties, low control accuracy, and difficulty in removing polishing products. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method and application of dynamically controlling electrochemical polishing using energy storage electrodes, so as to solve the technical problems in the existing technology of difficult-to-process metal materials such as nickel-based alloy glass, such as difficult operation, low control accuracy, and difficult discharge of polishing products.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for dynamically regulating electrochemical polishing using an energy storage electrode, using an energy storage electrode whose surface is modified with a multi-dimensional nanoarray and coated with a dielectric layer, dynamically regulates the potential and current density of the electrochemical polishing working fluid to maintain the potential and current density in the passivation zone.

[0006] Optionally, alternating positive and negative discontinuous pulses are used to control the energy storage electrode, including: during the entire process of electrochemical polishing, when the potential and current density of the working fluid are in the over-passivation range, a negative polarity pulse is emitted to enable the energy storage electrode to store charge; when the potential and current density of the working fluid are in the active dissolution range, a positive polarity pulse is emitted to enable the energy storage electrode to release charge.

[0007] Optionally, alternating positive and negative continuous pulses are used to control the energy storage electrode, including: issuing a positive polarity pulse to cause the energy storage electrode to release charge and simultaneously perform electrochemical polishing; issuing a negative polarity pulse to cause the energy storage electrode to store charge and simultaneously stop electrochemical polishing.

[0008] The present invention also includes the following technical features: Specifically and optionally, the present invention includes the following steps: Step 1: Measure the potential-current density curve of the workpiece to be processed in the electrochemical polishing working fluid. The potential-current density curve includes an active dissolution zone, a passivation zone, and an over-passivation zone.

[0009] Step 2: Use the electrode clamping device and the workpiece holder to fix the energy storage electrode and the workpiece to be processed in the polishing working tank respectively.

[0010] Step 3: Connect the energy storage electrode and the workpiece to be processed to the negative and positive electrodes of the bipolar nanosecond pulse power supply respectively.

[0011] Step 4: Connect and place the potential feedback device between the energy storage electrode and the workpiece to be processed, and place the current density feedback device between the bipolar nanosecond pulse power supply and the workpiece to be processed. Use the potential feedback device and the current density feedback device to control the bipolar nanosecond pulse power supply to emit positive and negative polarity pulses. Specifically, the voltage amplitude of the positive polarity pulse is 3 to 8V, preferably 5V; the duration of a single positive polarity pulse is 60 to 80ns; the voltage amplitude of the negative polarity pulse is -1 to -3V, preferably -2V; and the duration of a single negative polarity pulse is 50 to 90ns.

[0012] Step five, use discontinuous pulses for regulation: set the processing parameters and paths on the computer, and after the electrochemical polishing working fluid is filled into the polishing working tank and submerges the energy storage electrode and the workpiece to be processed, set the potential parameter of the bipolar nanosecond pulse power supply to the potential value of the passivation range and start the power supply, and control the up and down movement of the energy storage electrode through the industrial computer; discontinuous pulse control can be used for polishing processing throughout the entire process. When the measured values ​​of the potential feedback device and the current density feedback device are in the over-passivation range, the bipolar nanosecond pulse power supply emits a negative polarity pulse, and the energy storage electrode stores charge, so that the potential and current density are reduced to the passivation range; when the measured values ​​of the potential feedback device and the current density feedback device are in the active dissolution range, the bipolar nanosecond pulse power supply emits a positive polarity pulse, and the charge pre-stored in the energy storage electrode is released, so that the potential and current density are increased to the passivation range.

[0013] Step 6: After processing for a period of time, the electrochemical polishing requirements are met and the processing is stopped.

[0014] Specifically and optionally, the present invention includes the following steps: Step 1: Measure the potential-current density curve of the workpiece to be processed in the electrochemical polishing working fluid. The potential-current density curve includes an active dissolution zone, a passivation zone, and an over-passivation zone.

[0015] Step 2: Use the electrode clamping device and the workpiece holder to fix the energy storage electrode and the workpiece to be processed in the polishing working tank respectively.

[0016] Step 3: Connect the energy storage electrode and the workpiece to be processed to the negative and positive electrodes of the bipolar nanosecond pulse power supply respectively.

[0017] Step 4: Connect and place the potential feedback device between the energy storage electrode and the workpiece to be processed, and place the current density feedback device between the bipolar nanosecond pulse power supply and the workpiece to be processed, and control the bipolar nanosecond pulse power supply to emit positive polarity pulses and negative polarity pulses through the potential feedback device and the current density feedback device; specifically, the voltage amplitude of the positive polarity pulse is 3~8V, preferably 5V; the duration of a single positive polarity pulse is 150~200ns, preferably 180ns; the voltage amplitude of the negative polarity pulse is -1~-3V, preferably -2V; the duration of a single negative polarity pulse is 80~120ns, preferably 100ns.

[0018] Step five, use continuous pulses for control: set the processing parameters and paths on the computer, wait until the electrochemical polishing working fluid is filled into the polishing working tank and immerses the energy storage electrode and the workpiece to be processed, turn on the bipolar nanosecond pulse power supply to send out a negative polarity pulse to charge the energy storage electrode, and then perform electrochemical polishing when the bipolar nanosecond pulse power supply sends out a positive polarity pulse. During the polishing process, the energy storage electrode is controlled to move up and down by the industrial computer. The energy storage electrode is based on the potential-current density curve and is monitored and feedbacked in real time by the potential and current density. It releases charge autonomously and accurately to adjust the potential and current density of the working fluid; when a negative polarity pulse is sent, charge is stored and electrochemical polishing is stopped synchronously.

[0019] Step 6: After processing for a period of time, the electrochemical polishing requirements are met and the processing is stopped.

[0020] Specifically, the electrochemical polishing working solution is a sodium chloride-ethylene glycol solution with a concentration of 0.1 to 1 mol / L.

[0021] Specifically, the energy storage electrode is a carbon nanofiber energy storage electrode; the multidimensional nanoarray is composed of laterally grown nitrogen-doped carbon nanowires and vertically grown nitrogen-doped carbon nanotubes; and the dielectric layer is an aluminum oxide dielectric layer.

[0022] The present invention also protects the application of the above-mentioned method of dynamically controlling electrochemical polishing using energy storage electrodes in the processing of metal materials and amorphous alloy materials, such as nickel-based alloy glass.

[0023] Compared with the prior art, the present invention has the following technical effects: (I) This invention modifies the surface of an energy storage electrode with a multidimensional nanoarray. Utilizing the charge storage and release capabilities of the energy storage electrode and the multidimensional nanoarray, the amount of charge released each time is precisely controlled, stabilizing the potential and current density of the nanoworking fluid, ensuring that these remain within the passivation range suitable for precise polishing during the machining process. Simultaneously, the multidimensional nanoarray enhances mass transfer efficiency within the gap between the electrode and the workpiece being machined, as well as the removal of polishing products. This invention achieves high-precision control of potential and current density through simple operation, while also improving the removal of polishing products, ensuring polishing stability, and enhancing polishing efficiency and surface quality.

[0024] (II) The present invention realizes the directional and precise polishing of amorphous alloys and other materials under the complex microscopic conditions at the nanometer level. It is suitable for the electrochemical polishing of difficult-to-process metal materials such as stainless steel, titanium alloy, nickel-based alloy glass and amorphous alloy materials. The surface of the polished product can reach the nanometer level mirror surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of electrochemical polishing of energy storage electrodes.

[0026] Figure 2 This is an electron microscope image of the multi-dimensional nanoarray on the surface of the energy storage electrode.

[0027] Figure 3 Schematic diagram of the potential-current density curve of the workpiece in the nano-working fluid.

[0028] Figure 4 This is a diagram showing the working principle of the energy storage electrode controlling potential-current density in Example 2.

[0029] Figure 5 This is a diagram showing the working principle of the energy storage electrode controlling potential-current density in Example 3.

[0030] Figure 6 Schematic diagram of electrochemical polishing principle under positive polarity pulse.

[0031] Figure 7 Schematic diagram of electrochemical polishing principle under negative polarity pulse.

[0032] The meanings of the numbers in the figure are: 1-energy storage electrode; 2-workpiece to be processed; 3-multidimensional nanoarray; 4-potential feedback device; 5-current density feedback device; 6-bipolar nanosecond pulse power supply; 7-active dissolution zone; 8-passivation zone; 9-overpassivation zone; 10-positive polarity pulse; 11-negative polarity pulse; 12-current density range of passivation zone; 13-potential range of passivation zone; 14-hydrogen bubbles; 15-anions; 16-electrochemical polishing working fluid; 17-cations; 18-insoluble particles; 19-polishing working tank; 20-charge release; 21-charge storage; 22-oxygen bubbles. The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0033] It should be noted that, unless otherwise specified, all instruments in the present invention are instruments known in the art.

[0034] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0035] Example 1: This embodiment provides a nano-polishing device for dynamic control of energy storage electrode charge, such as Figure 1 As shown, it includes a bipolar nanosecond pulse power supply (6), the negative electrode of the power supply is electrically connected to the energy storage electrode (1), and a current density feedback device (5) is provided on the negative electrode connection circuit; the positive electrode of the power supply is electrically connected to the workpiece to be processed (2), and the positive electrode connection circuit and the negative electrode connection circuit are electrically connected to the potential feedback device (4).

[0036] In this embodiment, the preparation method of the energy storage electrode (1) is as follows: First, pretreatment: immerse the carbon nanofiber electrode in ethanol and deionized water for ultrasonic treatment for 15 minutes each to remove surface organic pollutants and dust, then bombard the surface with radio frequency plasma in an argon / oxygen mixed gas to increase surface active sites and hydrophilicity, then immerse the carbon nanofiber electrode in a mixture of concentrated nitric acid and sulfuric acid, reflux at 80°C for 2 hours to introduce functional groups such as carboxyl and hydroxyl groups, rinse with deionized water until neutral, and vacuum dry at 60°C for 12 hours. Second, catalyst loading: The nano-iron catalyst is evenly loaded onto the surface of the pretreated carbon nanofiber electrode by impregnation, and nano-scale catalytic particles are formed by precisely controlling the reduction temperature and time. Third, a multi-dimensional nanoarray is constructed in two steps by chemical vapor deposition: acetylene and ammonia are introduced to form vertically arranged nitrogen-doped carbon nanotubes; the temperature is lowered, acetylene and diborane are introduced, and lateral nitrogen-doped carbon nanowires are grown; finally, it is naturally cooled to room temperature in argon. The morphology of the multi-dimensional nanoarray is as follows: Figure 2 Fourth, functional modification: Atomic layer deposition technology is used to coat the surface of the multi-dimensional nanoarray with an ultra-thin dielectric layer of aluminum oxide to achieve precise control of charge storage and release behavior.

[0037] Example 2: This embodiment provides a method for dynamically controlling electrochemical polishing using an energy storage electrode, the method specifically comprising the following steps: Step 1: Determine the potential-current density curve of nickel-based metallic glass in 0.5 mol / L sodium chloride-ethylene glycol solution (nanoscale electrochemical polishing working solution 16), such as Figure 3 As shown in FIG, the potential-current density curve of nickel-based metallic glass includes an active dissolution region (7), a passivation region (8) and an over-passivation region (9).

[0038] Step 2: Use an electrode clamping device and a workpiece holder to fix the energy storage electrode (1) and the workpiece to be processed (2) in the polishing working tank (19); the specific capacitance and energy storage charge capacity of the energy storage electrode (1) are determined by the potential and current density range of the passivation zone of the potential-current density curve measured when the workpiece is in the nano-working fluid. In this embodiment, the specific capacitance of the energy storage electrode (1) is 8×10 −10 F / g.

[0039] Step 3: Connect the energy storage electrode (1) and the nickel-based metallic glass to the negative electrode and the positive electrode of the bipolar nanosecond pulse power supply (6) respectively.

[0040] Step 4: Connect and place the potential feedback device (4) between the energy storage electrode (1) and the nickel-based metallic glass, and place the current density feedback device (5) between the bipolar nanosecond pulse power supply (6) and the nickel-based metallic glass. The potential feedback device (4) and the current density feedback device (5) are used to control the bipolar nanosecond pulse power supply (6) to emit a positive polarity pulse (10) and a negative polarity pulse (11). The voltage amplitude of the positive polarity pulse (10) is 5V, and the duration of a single positive polarity pulse (10) is 60 to 80ns. The voltage amplitude of the negative polarity pulse (11) is -2V, and the duration of a single negative polarity pulse (11) is 50 to 90ns.

[0041] Step 5: Dynamic control using discontinuous pulses: Set the processing parameters and paths on the computer, wait until the 0.5 mol / L sodium chloride-ethylene glycol solution is filled into the polishing working tank (19) and immerses the energy storage electrode (1) and the nickel-based metallic glass, set the potential parameter of the bipolar nanosecond pulse power supply (6) to the potential value of the passivation range (8) and start the power supply; control the reciprocating motion of the Z axis through the industrial computer to drive the energy storage electrode (1) to move up and down.

[0042] In this embodiment, the discontinuous pulse control can be used for polishing throughout the entire process, and corresponding adjustments will be made as long as the passivation range is exceeded. Figure 4 、 Figure 6 and Figure 7As shown, when the measured values ​​of the potential feedback device (4) and the current density feedback device (5) are in the over-passivation range (9), the bipolar nanosecond pulse power supply (6) emits a negative polarity pulse (11), the energy storage electrode (1) performs charge storage (21), and the non-Faraday double-layer capacitance effect in the nanopore generates a reverse polarization potential, which offsets the external electric field strength, so that the potential and current density are reduced to the passivation range (8); when the measured values ​​of the potential feedback device (4) and the current density feedback device (5) are in the active dissolution range (7), the bipolar nanosecond pulse power supply (6) emits a positive polarity pulse (10), and the pre-stored charge in the energy storage electrode (1) is released (20), so that the potential and current density are increased to the passivation range (8); the polishing stability is guaranteed by the above adjustment process.

[0043] In this embodiment, Figure 6 and Figure 7 As shown in the figure, the principle of electrochemical polishing is as follows: cations (17) are reduced at the cathode, and the cathode reduction reaction produces hydrogen bubbles (14). Anions (15) migrate to the anode to participate in the reaction. Oxygen bubbles (22) are produced by water oxidation at the anode under high voltage or specific pH. Insoluble particles (18) including polishing products, salts or impurities are precipitated in the electrolyte, which may cause defects if attached to the workpiece surface.

[0044] Step 6: After processing for a period of time, the electrochemical polishing requirements are met and the processing is stopped.

[0045] Example 3: This embodiment provides a method for dynamically controlling electrochemical polishing using an energy storage electrode, the method specifically comprising the following steps: In this embodiment, steps 1, 2, 3, and 6 are exactly the same as steps 1, 2, 3, and 6 of embodiment 2.

[0046] Step 4: Connect and place the potential feedback device (4) between the energy storage electrode (1) and the nickel-based metallic glass, and place the current density feedback device (5) between the bipolar nanosecond pulse power supply (6) and the nickel-based metallic glass. The potential feedback device (4) and the current density feedback device (5) are used to control the bipolar nanosecond pulse power supply (6) to emit a positive polarity pulse (10) and a negative polarity pulse (11). The voltage amplitude of the positive polarity pulse (10) is 5V, and the duration of a single positive polarity pulse (10) is 180ns. The voltage amplitude of the negative polarity pulse (11) is -2V, and the duration of a single negative polarity pulse (11) is 100ns.

[0047] Step 5: Use continuous pulses for dynamic control: Figure 5 、 Figure 6 and Figure 7As shown, the processing parameters and paths are set on the computer. After the 0.5 mol / L sodium chloride-ethylene glycol solution is filled into the polishing working tank (19) to immerse the energy storage electrode (1) and the nickel-based metallic glass, the bipolar nanosecond pulse power supply (6) is turned on to send a negative polarity pulse (11) to charge the energy storage electrode (1), and the energy storage electrode (1) stores the charge (21); then, when the bipolar nanosecond pulse power supply (6) sends a positive polarity pulse (10), electrochemical polishing is performed. During the polishing process, the charge pre-stored in the energy storage electrode (1) is released (20). The Z-axis is controlled to reciprocate through the industrial computer, driving the energy storage electrode (1) to move up and down. The electrochemical polishing is stopped when the negative polarity pulse (11) is sent.

[0048] In this embodiment, continuous pulse control is to polish only when a positive polarity pulse is emitted, and to charge when a negative polarity pulse is emitted. Since an "interval" time is set during the polishing process, the product can be discharged in a timely manner. The energy storage electrode (1) releases the charge autonomously and accurately according to the potential-current density curve through real-time monitoring and feedback adjustment of the potential and current density. The specific capacitance and energy storage charge capacity characteristics of the energy storage electrode (1) more accurately control the potential and current density of the nano-working fluid within the passivation range (8), thereby achieving more accurate polishing.

[0049] Comparative Example 1: This comparative example provides a tungsten wire electrode-controlled nanopolishing method, which is basically the same as Example 2, except that a tungsten wire electrode is used instead of the energy storage electrode (1) whose surface is modified with a multi-dimensional nanoarray.

[0050] Comparative Example 2: This comparative example provides a tungsten wire electrode-controlled nanopolishing method, which is substantially the same as Example 3, except that a tungsten wire electrode is used instead of the energy storage electrode (1) whose surface is modified with a multi-dimensional nanoarray.

[0051] From the above examples and comparative examples, it can be seen that since the tungsten wire electrode does not have the ability to store and release charge, it is impossible to adjust the potential and current density of the 0.5 mol / L sodium chloride-ethylene glycol solution to the passivation range. The energy storage electrode (1) has significant advantages over the tungsten wire electrode: under the same process conditions, the energy storage electrode (1) can reduce the surface roughness of the workpiece from 12.5 nm to 2.3 nm (a reduction of 82%), increase the material removal rate to 3.5 μm / h (efficiency increased by 192%), and maintain the integrity of the electrode structure and processing stability (Ra fluctuation <±0.3 nm) after continuous operation for 10 hours. It is particularly noteworthy that the micro-eddy current effect generated by the multi-dimensional nano-array on the surface of the energy storage electrode (1) increases the discharge efficiency of the polishing product by 150%.

Claims

1. A method for dynamically controlling electrochemical polishing using an energy storage electrode, characterized in that: An energy storage electrode with a surface modified with a multi-dimensional nanoarray and coated with a dielectric layer is used to dynamically regulate the potential and current density of the electrochemical polishing working fluid so that the potential and current density are maintained in the passivation zone.

2. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 1, wherein: The energy storage electrode is controlled by alternating positive and negative discontinuous pulses, including: during the entire process of electrochemical polishing, when the potential and current density of the working fluid are in the over-passivation range, a negative polarity pulse is emitted to enable the energy storage electrode to store charge; when the potential and current density of the working fluid are in the active dissolution range, a positive polarity pulse is emitted to enable the energy storage electrode to release charge.

3. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 2, wherein: The voltage amplitude of the positive polarity pulse is 3 to 8V, and the duration of a single positive polarity pulse is 60 to 80ns; the voltage amplitude of the negative polarity pulse is -1 to -3V, and the duration of a single negative polarity pulse is 50 to 90ns.

4. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 1, wherein: The energy storage electrode is controlled by alternating positive and negative continuous pulses, including: issuing positive polarity pulses to release the energy storage electrode's charge and simultaneously perform electrochemical polishing; issuing negative polarity pulses to store the energy storage electrode's charge and simultaneously stop electrochemical polishing.

5. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 4, wherein: The voltage amplitude of the positive polarity pulse is 3 to 8V, and the duration of a single positive polarity pulse is 150 to 200ns; the voltage amplitude of the negative polarity pulse is -1 to -3V, and the duration of a single negative polarity pulse is 80 to 120ns.

6. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 1, wherein: During regulation, the energy storage electrode is controlled to move up and down or left and right.

7. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 1, wherein: The electrochemical polishing working fluid is an ethylene glycol solution of sodium chloride.

8. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 7, wherein: The concentration of the electrochemical polishing working solution is 0.1-1 mol / L.

9. The method for dynamically controlling electrochemical polishing using an energy storage electrode according to claim 1, wherein: The energy storage electrode is a carbon nanofiber energy storage electrode; The multidimensional nanoarray is composed of laterally grown nitrogen-doped carbon nanowires and vertically grown nitrogen-doped carbon nanotubes; The dielectric layer is an aluminum oxide dielectric layer.

10. Use of the method for dynamically controlling electrochemical polishing using an energy storage electrode as claimed in any one of claims 1 to 9 in the processing of metal materials and amorphous alloy materials.

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