A method and device for radio-chemical mechanical polishing of conductive porous hard materials

Abstract

The present invention provides a method for radio-electrochemical mechanical polishing of conductive porous hard materials: a polishing pad with through holes is attached to the bottom of a polishing disc of the same diameter; a pair of positive and negative electrodes are disposed on the bottom wall of each through hole, the two electrodes being merged into a bus bar at the top of the polishing disc and connected to the positive and negative poles of a power supply via a conductive slip ring; the conductive porous hard material is fixed to a polishing head; during processing, an electrolytic cell consisting of a polishing liquid layer, positive and negative electrodes, and the surface of the conductive porous hard material is formed at the bottom of the polishing disc, with the polishing pad separating the conductive porous hard material from the electrodes; after voltage is applied, oxidation and reduction reactions simultaneously occur at both ends of the surface of the conductive porous hard material in the electric field of the positive and negative poles, achieving polishing. The method provided by the present invention can efficiently process hard conductive porous hard materials, such as tungsten carbide, at room temperature and pressure, expanding the new method for processing hard conductive porous hard materials and the application range of electrochemical mechanical polishing, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy manufacturing, and specifically proposes a device and method for radio-chemical mechanical polishing of conductive porous hard materials. Background Art

[0002] Conductive porous hard materials typically consist of a hardening phase and a binder phase. Common hardening phases include transition metal carbides, nitrides, or borides, with tungsten carbide and boron nitride being the most widely used. The binder phase is often composed of iron-group elements such as cobalt or nickel. High-temperature sintering is typically used to tightly bond the two phases. Conductive porous hard materials offer advantages such as excellent toughness, high impact strength, high high-temperature hardness, high thermal and electrical conductivity, and excellent wear resistance. Therefore, they are widely used in engineering applications such as mold materials, hard tools, sensors, and corrosion-resistant coatings.

[0003] Conductive porous hard materials often require polishing to achieve a smooth, functional surface before being used in molds, parts, sensors, and coatings. The leading technology currently used is magnetorheological polishing (MRF). This process involves relative motion between the workpiece and a polishing disc. Driven by the rotating disc, a magnetorheological polishing fluid flows through the gap between the polishing disc and the workpiece. Under the influence of a high-gradient magnetic field, the magnetorheological polishing fluid transforms into a viscoplastic Bingham fluid. The polishing layer formed by the polishing particles on the fluid surface acts as a "reversible" grinding head, generating shear forces to remove material from the contact area of the workpiece surface, achieving polishing. However, cemented carbides such as tungsten carbide are extremely hard (e.g., tungsten carbide has a Mohs hardness of 9-9.5), resulting in a very low material removal rate (MRR) for MRF polishing. Furthermore, sintered materials are inherently porous, making existing polishing techniques such as MRF, which rely on material removal mechanisms, incapable of achieving a perfect mirror finish. This is one of the issues hindering the further application of porous hard materials.

[0004] Electrochemical oxidation of workpieces produces an oxide film that is softer than the workpiece material, making it a simple and efficient method for reducing surface hardness. Combining this with mechanical polishing forms traditional electrochemical mechanical polishing (ECMP). To date, only a few Chinese patents have disclosed methods for processing cemented carbide using a combination of electrochemical and mechanical polishing. For example, Chinese patent application number CN201920364328.X discloses a method for processing cemented carbide using electrolytic oxidation followed by mechanical polishing. However, this method suffers from low efficiency due to the accumulation of a passivation layer and poor surface quality. Chinese patent application number CN202210504556.9 discloses a method using micro-electrolytic polishing, which achieves good results, but the equipment required is complex. While these ECMP methods can achieve high MRRs, their processing mechanism still relies solely on material removal. However, the hardening and binder phases of cemented carbide have different oxidation potentials and rates, making these ECMP methods unresolved, leading to problems such as high surface roughness.

[0005] Innovative processing mechanisms that combine subtractive processing with additive processing can solve the above problems and obtain a smooth surface. The specific steps are as follows: (1) Subtractive processing that combines electrochemical oxidation with mechanical friction can preferentially remove high points on the workpiece surface; (2) Additive processing that deposits metal in the holes can fill the holes. For example, Chinese patent application number CN202211427430.2 discloses a method for polishing using alternating electrochemical oxidation and reduction to obtain a high-quality surface. However, during the polishing process, this method must directly connect the workpiece to an external power source through conductive glue and wires, so it cannot process workpieces and coatings with insulating substrates. In addition, during the polishing process, this method controls the oxidation and metal deposition on the workpiece surface by continuously switching the voltage. However, from the perspective of electrochemical theory, the electrode coefficient of a large-area workpiece surface is large, and it takes a long time for the surface double layer to be fully charged to reach the set potential. Therefore, this method has low processing efficiency and is difficult to accurately control oxidation and reduction, especially metal deposition in the material pores.

[0006] Our Chinese patent application number CN202110426699.8 discloses a method for polishing using wireless photoelectrochemical technology. However, the method and device provided in this patent do not utilize the reduction reaction in bipolar electrochemistry and are therefore only applicable to semiconductor processing. The method provided by the present invention expands upon the method of Chinese patent application number CN202110426699.8, developing a polishing method with greater universality and efficiency for the specialized processing of conductive porous hard materials, which has significant application value. Summary of the Invention

[0007] The purpose of the present invention is to provide a device and method for radio-chemical mechanical polishing of conductive porous hard material gold to solve the problems raised by the above background technology.

[0008] In order to achieve the above object, the solution of the present invention is:

[0009] A method for radio chemical mechanical polishing of a conductive porous hard material, comprising the following steps:

[0010] Fixing the conductive porous hard material workpiece on the polishing head;

[0011] Processing the polishing pad and the polishing plate to have a through-hole structure arranged in a honeycomb array;

[0012] Glue the polishing pad and polishing disc of the same size so that the through holes overlap;

[0013] A pair of positive and negative electrodes are arranged on the bottom wall of the through hole, the positive and negative electrodes are merged into the bus bar on the top of the polishing plate, and then connected to the positive and negative electrodes of the power supply through a conductive slip ring;

[0014] During the polishing process, the positive and negative electrodes are separated from the surface of the conductive porous hard material workpiece by the polishing pad, and the polishing liquid drips through the through hole onto the surface of the conductive porous hard material workpiece to form a polishing liquid layer, and the electrodes and the polishing liquid layer constitute an electrolytic cell;

[0015] During the polishing process, the conductive porous hard material workpiece and the polishing pad or the polishing disk rotate in the same direction. After voltage is applied, electrochemical oxidation and electrochemical reduction reactions occur simultaneously at different positions on the surface of the conductive porous hard material workpiece in the electrolytic cell, and the electrochemical process and the mechanical friction removal process are evenly alternated.

[0016] Furthermore, the dripping rate of the polishing liquid into the through hole is 10mL / min~120ml / min. If it is too low, the electrolytic cell structure cannot be effectively formed, and if it is too high, the current of the electrolytic cell is too large and the heat is serious; the pH value of the polishing liquid is 1~13, containing 0.001-0.01M CoSO4 solution or NiSO4 solution. Too low or too high pH will cause serious corrosion of the equipment; too low metal ion concentration cannot effectively achieve electrodeposition, and too high self-precipitation is likely to occur.

[0017] Furthermore, the applied voltage is 5V to 60V; if the voltage is too low, the processing cannot be achieved, while if the voltage is too high, the electrolytic cell will generate severe heat.

[0018] Furthermore, the conductive porous hard material is a composite material prepared by sintering one of tungsten carbide, silicon carbide, silicon nitride or boron nitride hard powder materials with one of metals nickel, chromium or cobalt at high temperature.

[0019] A radio-chemical mechanical polishing device for conductive porous hard materials comprises a polishing head, a conductive porous hard material workpiece, a polishing disc, a polishing pad, positive and negative electrode busbars, a conductive slip ring, a DC power supply, a polishing liquid nozzle and a polishing liquid recovery tank; wherein the polishing disc and the polishing pad both have through holes arranged in a honeycomb array; the polishing pad retaining through holes are correspondingly adhered to the bottom of the polishing disc; positive and negative electrode busbars are arranged on the top of the polishing disc, the busbars are connected to the DC power supply through the conductive slip ring, and the busbars merge into the side walls of the bottom of the polishing disc to form the positive and negative poles of the electrolytic cell; the positive and negative electrodes are separated from the conductive porous hard material workpiece by the polishing pad.

[0020] Furthermore, the diameter of the conductive porous hard material is 20 mm to 204 mm.

[0021] Furthermore, the polishing pad and the polishing plate have the same diameter, which is 20 cm to 100 cm. If the diameter is too small, a through-hole structure cannot be constructed, and if it is too large, the polishing pressure will be uneven during processing. The polishing pad and the polishing plate both have through-holes arranged in a honeycomb array, and the area of the through-holes is 0.07 cm. 2 ~1cm 2 If the area is too small, the current will be too large and the heat will be serious. If the area is too large, a larger voltage will need to be applied. The polishing pad and polishing disk are both made of electrically insulating materials. The thickness of the polishing disk is 2cm to 5cm. If the thickness is too thin, the structure of the polishing disk will be unstable. If it is too thick, the rotation speed of the polishing disk will be limited.

[0022] Furthermore, the electrode materials of the positive and negative electrodes are alloys formed by one or more of platinum, tantalum, ruthenium, iridium or niobium.

[0023] Furthermore, the positive and negative electrode areas are 0.1 mm 2 ~10mm 2 The shape of the electrode is sheet-shaped, linear, disc-shaped or one or more combinations thereof; if the electrode area is too small, it will lead to uneven electric field, while if the electrode area is too large, the current will be too large and the heat will be serious.

[0024] Furthermore, the busbar is a wire wrapped with a waterproof insulation layer.

[0025] The method provided by the present invention is based on the principle of combining subtractive and additive machining to achieve uninterrupted electrochemical oxidation and electrochemical metal deposition on the surface of a conductive porous hard material workpiece based on the principle of bipolar electrochemistry. That is, the surface of the conductive porous hard material workpiece is in an electric field between two electrodes, but is not directly in contact with the positive and negative electrodes, but is separated by a layer of polishing liquid. Specifically, although the surface of the conductive porous hard material workpiece is continuous and not physically separated, electrochemical oxidation and reduction reactions can occur simultaneously at its two ends during the polishing process, hence the term bipolar electrochemistry. In addition, wireless bipolar electrochemistry is different from traditional electrochemical methods. In principle, it can cause oxidation and metal electrodeposition to occur simultaneously on the workpiece surface. The specific principle is briefly introduced as follows: when a conductive porous hard material workpiece is immersed in an electrolyte but not in direct contact with the positive and negative electrode pairs on both sides, the electric field established by the positive and negative electrodes in the electrolyte will drive the electrons on the workpiece surface from the side close to the negative electrode to the side close to the positive electrode; thus, the side with fewer electrons becomes the anode for oxidation reaction, which can be combined with mechanical friction to remove the oxide film located on the protruding part of the surface, while the other side with more electrons becomes the cathode for metal electrodeposition to fill the hole; during the processing process, the workpiece and the polishing disk rotate in the same direction, and the potential of each point on the workpiece surface can achieve a natural conversion between anode and cathode, which is different from the step-type sudden conversion of traditional electrochemistry, which requires a sufficiently long time to fully charge the surface double layer to reach the set potential. Therefore, the method provided by the present invention has high processing efficiency and can accurately control oxidation and reduction, especially metal electrodeposition in the pores of hard porous materials.

[0026] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The method of radio-chemical mechanical polishing of conductive porous hard material workpieces provided by the present invention does not require expensive experimental equipment and cumbersome steps, nor does it involve extreme conditions such as high temperature, high pressure and vacuum. Various conductive porous hard material workpieces can be processed under mild conditions, and has the advantages of simple operation and practical convenience.

[0028] (2) The method of radio chemical mechanical polishing of a conductive porous hard material workpiece provided by the present invention can complete the global polishing of the conductive porous hard material workpiece in a short time, with high polishing efficiency, and the surface of the conductive porous hard material workpiece obtained is smooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 Schematic diagram of the radio-chemical mechanical polishing processing device used in the present invention; in the figure: 1. polishing liquid recovery tank, 2. polishing head, 3. conductive porous hard material workpiece, 4. polishing pad, 5. polishing disk, 6. positive and negative electrodes, 7. positive and negative electrode bus bars, 8. polishing liquid nozzle, 9. conductive slip ring, 10. DC power supply.

[0031] Figure 2 This is a schematic diagram of the structure of the electrochemical electrolytic cell at the bottom of the through hole of the polishing disk of the present invention.

[0032] Figure 3 This is a laser confocal microscope image of the shape analysis of the surface of the tungsten carbide / metal cobalt conductive porous hard material workpiece used in Example 2 of the present invention after traditional electrochemical mechanical polishing.

[0033] Figure 4 This is a laser confocal microscope image of the shape analysis of the tungsten carbide / metal cobalt conductive porous hard material workpiece used in Example 3 of the present invention after radio chemical mechanical polishing. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0035] The present invention does not impose any restrictions on the polishing process time. The types of polishing liquids used in the following examples are for the convenience of experiment and are not considered to be limiting on the types of polishing liquids.

[0036] Example 1: Radio-chemical mechanical polishing device for conductive porous hard material workpiece

[0037] Figure 1A schematic diagram of the radio chemical mechanical polishing device for a conductive porous hard material workpiece provided by the present invention includes a polishing head (2), a conductive porous hard material workpiece (3), a polishing pad (4), a polishing disc (5), a polishing liquid nozzle (8), a conductive slip ring (9), positive and negative electrodes (6), positive and negative electrode bus bars (7), a DC power supply (10) and a polishing liquid recovery tank (1); the polishing pad is attached to the bottom of the polishing disc; wherein the polishing pad and the polishing disc have through holes arranged in the same honeycomb array; a pair of positive and negative electrodes (6) are arranged on the bottom wall of the through hole, The positive and negative electrodes are upwardly merged into the bus bar on the top of the polishing disk, and the bus bar is respectively connected to the positive and negative electrodes of the power supply through a conductive slip ring; a polishing pad is provided under the electrode to separate it from the conductive porous hard material workpiece; the conductive porous hard material workpiece is fixed on the polishing head: during processing, the polishing liquid drips into the through hole and flows to the surface of the conductive porous hard material workpiece, the polishing disk or the polishing pad is pressed against the surface of the conductive porous hard material workpiece, the conductive porous hard material workpiece and the polishing pad or the polishing disk rotate in the same direction, and after voltage is applied, the conductive porous hard material workpiece can be electrochemically mechanically polished.

[0038] In this embodiment, the conductive porous hard material workpiece to be processed is made of tungsten carbide / metal cobalt, with a diameter of 10 mm to 204 mm, and more preferably YG8 tungsten carbide-cobalt cemented carbide, with a diameter of 50.8 mm.

[0039] In this embodiment, the polishing pad and the polishing disk are both made of electrically insulating materials, more preferably a SUBA800 polishing pad, and the polishing disk is made of polytetrafluoroethylene.

[0040] In this embodiment, the polishing pad and the polishing plate have through holes of the same diameter and arranged in a honeycomb array. The diameter of the polishing pad and the polishing plate is 20 cm to 100 cm, and the area of each through hole is 0.07 cm. 2 ~1cm 2 , further preferably the diameter is 23 cm, and the diameter of each circular through hole is 0.6 cm.

[0041] In this embodiment, the thickness of the polishing disc is 2 cm to 5 cm, and more preferably the thickness is 2.3 cm.

[0042] In this embodiment, a pair of positive and negative electrodes are provided on the bottom wall of each through hole of the polishing disk, and the electrode material is an alloy formed by one or more of platinum, tantalum, ruthenium, iridium or niobium, and more preferably metal platinum.

[0043] In this embodiment, the positive and negative electrodes are in the shape of disk, line or sheet, or a combination thereof, and the electrode area is 0.1 mm 2 ~10mm 2, further preferably a linear electrode, and further preferably a diameter of 0.3 mm and a length of 2 mm.

[0044] In this embodiment, the positive and negative electrodes are incorporated into the bus bar and connected to the positive and negative terminals of the power supply via a conductive slip ring. The conductive connection uses a wire wrapped in a waterproof insulation layer, more preferably a copper wire wrapped in polytetrafluoroethylene, and further preferably a copper conductive wire with a diameter of 0.5 mm.

[0045] In this embodiment, the pressure at which the polishing disc bottom is pressed against the conductive porous hard material workpiece is 4 psi to 8 psi, more preferably 5 to 7 psi.

[0046] In this embodiment, the polishing liquid drips into the through hole at a rate of 50 ml / min to 120 ml / min, more preferably 100 mL / min.

[0047] In this embodiment, the pH value of the polishing liquid is 1-13, and the conductivity is 0.5s / m-2s / m. More preferably, the pH value is 9-13, and the conductivity is 0.5s / m-1s / m. More preferably, the pH value is 12, and the conductivity is 0.8s / m.

[0048] In this embodiment, the voltage applied to each electrolytic cell is 5V to 60V, more preferably 30V to 50V.

[0049] In this embodiment, the conductive porous hard material and the polishing pad or the polishing plate rotate in the same direction at a rotation speed of 50 rpm to 300 rpm, more preferably 200 rpm.

[0050] Figure 2 This is a schematic diagram of the electrochemical cell structure at the bottom of the polishing plate's through-holes: Two 0.3mm diameter platinum wires are placed vertically at the bottom of each through-hole on the polishing plate and fixed at both ends of the through-hole diameter, with the ends of the platinum wires aligned with the bottom surface of the polishing plate. Conductive glue is used to bond them to a PTFE-coated copper wire, and then epoxy glue is used to coat the platinum wires and the conductive bonding area, leaving only 2mm of each platinum wire end exposed. The copper wires are incorporated into the busbars on the top of the polishing plate and connected to the positive and negative terminals of the power supply via conductive slip rings.

[0051] Example 2

[0052] The conductive porous hard material radio chemical mechanical polishing device described in Example 1 was used to process the conductive porous hard material workpiece, wherein a polishing disk with a diameter of 23 cm (thickness of 2.0 cm) and a polishing pad (SUBA800) were selected, and 131 through holes with a diameter of 0.6 cm were arranged in a Fibonacci array; the structure of the electrochemical electrolytic cell used was consistent with that described in Example 1. The method for radio-chemical mechanical polishing of a conductive porous hard material workpiece comprises the following steps: a YG8 tungsten carbide-cobalt (1.5 mm thick, 50.8 cm diameter) is secured to a polishing head with wax, with a pressure of 5 psi between the polishing pad and the workpiece. The polishing solution has a pH of 5 and contains 10 wt% Al2O3 abrasive particles with an average diameter of 50 nm and 0.01 M CoSO4. The polishing solution is continuously dripped onto the polishing pad at a rate of 100 ml / min. The motor is powered, rotating the polishing pad and the workpiece secured to the polishing head at 200 rpm. The power supply is turned on, a 15 V DC voltage is applied to all electrochemical cells, and the polishing process begins. After 0.5 hours of processing, the power supply, motor, and fluid supply system are sequentially turned off. The polishing head is removed, the workpiece is rinsed with dewaxing water, ethanol, and ultrapure water, and then the Al2O3 nanoparticles are dissolved in 0.1 mol / L KOH in an ultrasonic bath for 2 minutes. The workpiece is then passed through a megasonic ultrapure water bath for 5 minutes and then blown dry with nitrogen. The weight reduction of the workpiece carbide after processing was measured using a high-precision balance with an accuracy of one hundred thousandth. The material removal rate was calculated to be 0.32μm / min from the density and surface area of YG8 tungsten carbide-cobalt, which greatly improved the processing efficiency. The shape analysis was performed using a laser confocal microscope ( Figure 3 As shown in FIG, the surface roughness Sa of the processed surface is 84.6 nm, and the method used can obtain a flat surface.

[0053] Example 3

[0054] The conductive porous hard material radio chemical mechanical polishing device described in Example 1 was used to process a tungsten carbide-cobalt hard alloy workpiece (with a diameter of 50.8 cm and a thickness of 1.5 mm). Figure 1Schematic diagram of the machining apparatus used. The components were installed in their respective positions. The pressure between the polishing pad and the carbide was 7.5 psi. A polishing solution with a pH of 10 and containing 10 wt% diamond particles with an average diameter of 25 nm and 0.001 M CoSO₄ was continuously dripped onto the polishing pad at a rate of 100 mL / min. The polishing solution had a pH of 10 and contained 10 wt% diamond particles with an average diameter of 25 nm and 0.001 M CoSO₄. The motor was powered, rotating the polishing pad and the workpiece mounted on the polishing head at 204 rpm. The power supply was turned on, and a 10 V DC voltage was applied to all electrochemical cells to initiate the polishing process. After 0.5 hours of processing, the power supply, motor, and fluid supply system were sequentially turned off. The polishing head was removed, and the tungsten carbide workpiece was removed and cleaned sequentially with dewaxing water, ethanol, and ultrapure water. The diamond particles were then removed by ultrasonication in 0.1 mol / L KOH for 2 minutes. The workpiece was then placed in a megasonic ultrapure water bath for 5 minutes and then dried with nitrogen. The weight reduction of the cemented carbide after processing was measured using a high-precision balance with an accuracy of one hundred thousandth. The material removal rate was calculated to be 0.513μm / min based on the density and surface area of the cemented carbide. The processing efficiency was greatly improved. The shape analysis was performed using a laser confocal microscope ( Figure 4 ) shows that the surface roughness Sa of the processed surface is 67.1nm, and this method can obtain a flat surface.

[0055] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0056] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for radio chemical mechanical polishing of conductive porous hard materials, characterized in that: The specific steps are as follows: Fixing the conductive porous hard material workpiece on the polishing head; Processing the polishing pad and the polishing plate to have a through-hole structure arranged in a honeycomb array; Glue the polishing pad and polishing disc of the same size so that the through holes overlap; A pair of positive and negative electrodes are arranged on the bottom wall of the through hole, the positive and negative electrodes are merged into the bus bar on the top of the polishing plate, and then connected to the positive and negative electrodes of the power supply through a conductive slip ring; During the polishing process, the positive and negative electrodes are separated from the surface of the conductive porous hard material workpiece by the polishing pad, and the polishing liquid drips through the through hole onto the surface of the conductive porous hard material workpiece to form a polishing liquid layer, and the positive and negative electrodes and the polishing liquid layer constitute an electrolytic cell; During the polishing process, the conductive porous hard material workpiece and the polishing pad or the polishing disk rotate in the same direction. After voltage is applied, electrochemical oxidation and electrochemical metal electrodeposition reactions simultaneously occur at different positions on the surface of the conductive porous hard material workpiece in the electrolytic cell, and the electrochemical process and the mechanical friction removal process are evenly alternated.

2. The method for radio chemical mechanical polishing of a conductive porous hard material according to claim 1, characterized in that: The polishing liquid drips into the through hole at a rate of 10 mL / min to 120 ml / min; the polishing liquid has a pH value of 1 to 13 and contains 0.001-0.01 M CoSO4 solution or NiSO4 solution.

3. The method for radio chemical mechanical polishing of a conductive porous hard material according to claim 1, characterized in that: The applied voltage is 5 V to 60 V.

4. The method for radio chemical mechanical polishing of a conductive porous hard material according to claim 1, characterized in that: The conductive porous hard material is a composite material prepared by sintering one of tungsten carbide, silicon carbide, silicon nitride or boron nitride hard powder materials with one of metals nickel, chromium or cobalt at high temperature.

5. A radio chemical mechanical polishing device for conductive porous hard materials used in the method according to any one of claims 1 to 4, characterized in that: It includes a polishing head, a conductive porous hard material workpiece, a polishing disc, a polishing pad, positive and negative electrode busbars, a conductive slip ring, a DC power supply, a polishing liquid nozzle and a polishing liquid recovery tank; wherein, the polishing disc and the polishing pad both have through holes arranged in a honeycomb array; the polishing pad holding through holes are correspondingly adhered to the bottom of the polishing disc; positive and negative electrode busbars are arranged on the top of the polishing disc, the busbars are connected to the DC power supply through the conductive slip ring, and the busbars are merged into the side wall of the bottom of the polishing disc to form the positive and negative poles of the electrolytic cell; the positive and negative electrodes are separated from the conductive porous hard material workpiece by the polishing pad.

6. The radio chemical mechanical polishing device for conductive porous hard materials according to claim 5, characterized in that: The diameter of the conductive porous hard material is 20 mm to 204 mm.

7. The radio chemical mechanical polishing device for conductive porous hard materials according to claim 5, characterized in that: The polishing pad and the polishing plate have the same diameter, which is 20 cm to 100 cm; the polishing pad and the polishing plate both have through holes arranged in a honeycomb array, and the area of the through holes is 0.07 cm 2 ~1 cm 2 ; The polishing pad and polishing disc are made of electrically insulating materials; the thickness of the polishing disc is 2 cm~5 cm.

8. The radio chemical mechanical polishing device for conductive porous hard materials according to claim 5, characterized in that: The electrode materials of the positive and negative electrodes are alloys formed by one or more of platinum, tantalum, ruthenium, iridium or niobium.

9. The radio chemical mechanical polishing device for conductive porous hard materials according to claim 5, characterized in that: The positive and negative electrode areas are 0.1 mm 2 ~10 mm 2 The positive and negative electrodes are in the shape of sheets, lines, discs or one or more combinations thereof.

10. The radio chemical mechanical polishing device for conductive porous hard materials according to claim 5, characterized in that: The busbar is a conductor wrapped with a waterproof insulation layer.

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