CN116728167A - Method and device for conducting porous hard material wireless electrochemical mechanical polishing - Google Patents
Method and device for conducting porous hard material wireless electrochemical mechanical polishing Download PDFInfo
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- CN116728167A CN116728167A CN202310426153.1A CN202310426153A CN116728167A CN 116728167 A CN116728167 A CN 116728167A CN 202310426153 A CN202310426153 A CN 202310426153A CN 116728167 A CN116728167 A CN 116728167A
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- 238000006722 reduction reaction Methods 0.000 claims abstract description 12
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims abstract description 12
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 12
- 239000000956 alloy Substances 0.000 claims description 9
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- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 2
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/005—Control means for lapping machines or devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
- B24B37/07—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool
- B24B37/10—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for single side lapping
- B24B37/105—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for single side lapping the workpieces or work carriers being actively moved by a drive, e.g. in a combined rotary and translatory movement
- B24B37/107—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for single side lapping the workpieces or work carriers being actively moved by a drive, e.g. in a combined rotary and translatory movement in a rotary movement only, about an axis being stationary during lapping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/006—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the speed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/16—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the load
- B24B49/165—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the load for grinding tyres
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F3/00—Electrolytic etching or polishing
- C25F3/16—Polishing
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
The invention provides a wireless electrochemical mechanical polishing method for a conductive porous hard material, which comprises the following steps: adhering polishing pads with through holes to the bottoms of polishing discs with the same diameter; a pair of positive and negative electrodes are arranged on the bottom wall of each through hole, the two electrodes are integrated into a bus line at the top of the polishing disc and are connected with the positive and negative electrodes of a power supply through a conductive slip ring; fixing the porous hard material on the polishing head; during processing, an electrolytic cell consisting of a polishing liquid layer, positive and negative electrodes and conductive porous hard material surfaces is formed at the bottom of the polishing disk, and the polishing pad separates the conductive porous hard material from the electrodes; after voltage is applied, oxidation and reduction reactions simultaneously occur at two ends of the surface of the conductive porous hard material in the electric field of the positive electrode and the negative electrode to realize polishing. The method provided by the invention can be used for efficiently processing the hard conductive porous hard material represented by tungsten carbide at normal temperature and normal pressure, expands a novel method for processing the hard conductive porous hard material and the application range of electrochemical mechanical polishing, and has wide application prospect.
Description
Technical Field
The invention belongs to the technical field of alloy manufacturing, and particularly provides a device and a method for wireless electrochemical mechanical polishing of a conductive porous hard material.
Background
The conductive porous hard material is usually composed of a hardening phase and a binding phase, wherein the common hardening phase is carbide, nitride or boride of transition metal, and the most widely used hardening phase is tungsten carbide and boron nitride; the binding phase is mainly cobalt or nickel and other iron group elements; high temperature sintering is typically used to tightly bond the two phases. The conductive porous hard material has the advantages of good toughness, high impact strength, high-temperature hardness, high heat conductivity, high electrical conductivity, good wear resistance and the like, and is widely applied to the engineering fields of mold materials, hard tools, sensors, corrosion-resistant coatings and the like.
Electrically conductive porous hard materials typically require a polishing process to obtain a smooth functional surface prior to making the mold, part, sensor, and coating. The main technology at present is magneto-rheological polishing (MRF), wherein the processing mechanism is that a workpiece and a polishing disk relatively move, and when the magneto-rheological polishing liquid flows through a gap between the polishing disk and the workpiece under the drive of the rotating polishing disk, the magneto-rheological polishing liquid becomes viscoplastic Bingham fluid under the action of a high gradient magnetic field; the polishing layer formed by the polishing particles on the surface of the fluid can be used as a reversible grinding head to generate shearing force to remove materials on the contact area of the surface of the workpiece, so that polishing is realized. However, hard alloys such as tungsten carbide are extremely high in hardness (e.g., 9-9.5 Mohs hardness of tungsten carbide), and MRF polishing has very low Material Removal Rate (MRR). More importantly, the sintered material is a porous material, and the existing polishing technology such as MRF based on a material removal mechanism cannot process the surface of the sintered material to an ideal mirror surface, which is one of the problems that restrict the further application of porous hard materials.
Electrochemical oxidation of a workpiece can produce an oxide film softer than the workpiece material, is a simple and efficient method for reducing the surface hardness of the workpiece, and is combined with mechanical polishing to obtain the traditional electrochemical mechanical polishing (ECMP). To date, only a few chinese patents disclose methods for processing cemented carbides using electrochemical and mechanical polishing in combination. For example: chinese patent application No. cn201920364328.X discloses a method of electrolytic oxidation followed by mechanical polishing of cemented carbide, which has disadvantages in that the accumulation of passivation layer causes inefficiency and the obtained surface quality is poor. Chinese patent application No. CN202210504556.9 discloses a polishing method using micro-electrolysis, which achieves good results, but the equipment required for the method is too complex. While these ECMPs can achieve high MRR, their processing mechanisms still rely solely on material removal. However, the hard alloy hardening phase and the binder phase have different oxidation potentials and oxidation rates, and the problem of large processed surface roughness cannot be solved by using the ECMP methods.
Innovatively combining subtractive processing with additive processing from a processing mechanism can solve the problems, and a smooth surface is obtained, and the method comprises the following specific steps: (1) The high points on the surface of the workpiece can be preferentially removed by adopting material reduction processing combining electrochemical oxidation and mechanical friction; (2) Additive processing of electrodepositing metal within the hole may fill the hole. For example; chinese patent application number CN202211427430.2 discloses that high quality surfaces can be obtained using an electrochemical oxidation and reduction alternating polishing process; however, in the polishing process, the workpiece and an external power supply are directly connected through conductive adhesive and a wire, so that the workpiece and the coating of the insulating substrate cannot be processed; in addition, the method controls oxidation and metal deposition on the surface of the workpiece by continuously switching voltages during polishing, but in electrochemical theory, the electrode coefficient of the surface of the workpiece with large area is large, and a sufficient time is required to fully charge the electric double layer on the surface to a set potential, so that the method has low processing efficiency and is not easy to accurately control oxidation and reduction, particularly metal electrodeposition in a material hole.
Our chinese patent with application number CN202110426699.8 discloses a polishing method using wireless photoelectrochemical technology, but the method and apparatus provided by this patent do not utilize reduction reactions in bipolar electrochemistry and are therefore only suitable for semiconductor processing. The method provided by the invention is an expansion of the Chinese patent needle with the application number of CN202110426699.8, and a polishing method with wider universality and higher efficiency is developed aiming at a special processing object of the conductive porous hard material, so that the method has important application value.
Disclosure of Invention
The invention aims to provide a device and a method for wireless electrochemical mechanical polishing of conductive porous hard material gold, which solve the problems in the prior art.
In order to achieve the above object, the solution of the present invention is:
a method for conducting porous hard material wireless electrochemical mechanical polishing comprises the following specific steps:
fixing the conductive porous hard material workpiece on a polishing head;
processing the polishing pad and the polishing disk into a through hole structure with honeycomb array arrangement;
pasting polishing pads and polishing discs with the same size in a mode that through holes are overlapped;
a pair of positive and negative electrodes are arranged on the bottom wall of the through hole, are integrated into a bus line at the top of the polishing disk, and are then connected with the positive and negative electrodes of a power supply through a conductive slip ring;
in the polishing process, the positive electrode and the negative electrode are separated from the surface of the conductive porous hard material workpiece by the polishing pad, polishing liquid passes through the through holes and is dripped on the surface of the conductive porous hard material workpiece to form a polishing liquid layer, and the electrode and the polishing liquid layer form an electrolytic cell;
in the polishing process, the conductive porous hard material workpiece and the polishing pad or the polishing disk rotate in the same direction, electrochemical oxidation and electrochemical reduction reactions are simultaneously carried out at different positions on the surface of the conductive porous hard material workpiece in the electrolytic cell after voltage is applied, and the electrochemical process and the mechanical friction removal process are uniformly and alternately carried out.
Further, the dropping speed of the polishing solution into the through hole is 10-120 mL/min, the polishing solution is too low to form an electrolytic cell structure effectively, and the current of the electrolytic cell is too high to generate serious heat; the pH value of the polishing solution is 1-13, and the polishing solution containsWith 0.001-0.01M CoSO 4 Solutions or NiSO 4 Too low or too high a pH of the solution can lead to severe corrosion of the equipment; too low a concentration of metal ions does not allow electrodeposition to be effectively achieved, and too high a concentration tends to precipitate itself.
Further, the applied voltage is 5V-60V; too low a voltage does not allow processing, while too high a voltage causes severe heating of the cell.
Further, the conductive porous hard material is a composite material prepared by sintering one of tungsten carbide, silicon nitride or boron nitride hard powder material and one of metallic nickel, chromium or cobalt at high temperature.
A wireless electrochemical mechanical polishing device of conductive porous hard materials comprises a polishing head, a conductive porous hard material workpiece, a polishing disk, a polishing pad, positive and negative electrode bus lines, a conductive slip ring, a direct current power supply, a polishing liquid spray head and a polishing liquid recovery groove; wherein, the polishing disk and the polishing pad are provided with through holes which are arranged in a honeycomb array; the polishing pad holding through holes are correspondingly stuck to the bottom of the polishing disc; positive and negative electrode bus lines are arranged at the top of the polishing disk, the bus lines are connected to the direct current power supply through the conductive slip rings, and the bus lines are converged into the side wall of the bottom of the polishing disk to form the positive and negative electrodes of the electrolytic cell; the positive and negative electrodes are separated from the conductive porous hard material workpiece by a polishing pad.
Further, the diameter of the conductive porous hard material is 20 mm-204 mm.
Further, the polishing pad and the polishing disk have the same diameter, and the diameter is 20 cm-100 cm; the diameter is too small to construct a through hole structure, and the polishing pressure is uneven when the diameter is too large for processing; the polishing pad and the polishing disk are provided with through holes which are arranged in a honeycomb array, and the area of each through hole is 0.07cm 2 ～1cm 2 The area is too small, so that the current is too large to generate heat seriously, and larger voltage is required to be applied when the area is too large; the polishing pad and the polishing disk are made of electrically insulating materials; the thickness of the polishing disc is 2 cm-5 cm, the structure of the polishing disc is unstable due to the fact that the thickness is too thin, and the rotation speed of the polishing disc is limited due to the fact that the thickness is too thick.
Further, the electrode material of the positive and negative electrodes is an alloy formed by one or more of platinum, tantalum, ruthenium, iridium or niobium.
Further, the area of the positive electrode and the negative electrode is 0.1mm 2 ～10mm 2 The shape of the electrode is one or more of sheet, linear, disk or combination; too small an electrode area may result in non-uniform electric fields, while too large an electrode area may result in too much current and severe heating.
Further, the bus line is a wire wrapped by a waterproof insulating layer.
The principle of the method provided by the invention is that the material reduction processing and the material increase processing are combined, and the uninterrupted electrochemical oxidation and electrochemical deposition of metal on the surface of the conductive porous hard material workpiece are realized based on the bipolar electrochemical principle, namely: the surface of the conductive porous hard material workpiece is positioned in an electric field between two electrodes, but is not directly contacted with the positive electrode and the negative electrode, but is provided with a polishing liquid layer at intervals; specifically, although the surface of the conductive porous hard material workpiece is in a continuous, non-physically separated state, both ends thereof may undergo electrochemical oxidation and reduction reactions, respectively, simultaneously during polishing, and thus are called bipolar electrochemistry. In addition, unlike the traditional electrochemical method, the wireless bipolar electrochemical method can enable the surface of a workpiece to be oxidized and electrodeposited simultaneously, and the specific principle is as follows: when the conductive porous hard material workpiece is immersed in the electrolyte but is not in direct contact with the positive electrode and the negative electrode on the two sides, an electric field established by the positive electrode and the negative electrode in the electrolyte drives electrons on the surface of the workpiece to flow from the side close to the negative electrode to the side close to the positive electrode; thus, one side with less electrons becomes an anode to generate oxidation reaction, the oxidation film positioned on the surface protruding part can be removed by combining mechanical friction, and the other side with more electrons becomes a cathode to generate metal electrodeposition filling holes; in the processing process, the workpiece and the polishing disk rotate in the same direction, the potential of each point on the surface of the workpiece can realize the natural conversion between the anode and the cathode, and the method is different from the conventional electrochemical step-by-step abrupt change conversion in that the electric double layer on the surface can be fully charged to reach the set potential in a long enough time, so that the method provided by the invention has high processing efficiency and can accurately control oxidation and reduction, and particularly, the metal electrodeposition in the pores of the hard porous material.
Compared with the prior art, the invention has the following beneficial effects:
(1) The method for polishing the conductive porous hard material workpiece by the wireless electrochemical machinery does not need expensive experimental equipment and complicated steps, does not involve extreme conditions such as high temperature, high pressure, vacuum and the like, can process various conductive porous hard material workpieces under mild conditions, and has the advantages of simplicity in operation, practicability, convenience and the like.
(2) The method for polishing the conductive porous hard material workpiece by the wireless electrochemical machinery can finish overall polishing of the conductive porous hard material workpiece in a short time, has high polishing efficiency, and has smooth surface.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a wireless electrochemical mechanical polishing apparatus used in the present invention; in the accompanying drawings: 1. the polishing device comprises a polishing liquid recovery tank, a polishing head, a conductive porous hard material workpiece, a polishing pad, a polishing disk, positive and negative electrodes, positive and negative electrode bus lines, a polishing liquid spray head, a conductive slip ring and a direct current power supply.
FIG. 2 is a schematic view of the structure of an electrochemical cell at the bottom of a through hole of a polishing disk according to the present invention.
FIG. 3 is a laser confocal microscope image of the shape analysis of the surface of a workpiece of a tungsten carbide/cobalt metal conductive porous hard material used in example 2 of the present invention after conventional electrochemical mechanical polishing.
FIG. 4 is a laser confocal microscope image of the shape analysis of a tungsten carbide/cobalt metal conductive porous hard material workpiece used in example 3 of the present invention after wireless electrochemical mechanical polishing.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The polishing time is not limited by the present invention, and the types of polishing solutions used in the following examples are all for convenience of experiment and are not considered to be limiting.
Example 1 Wireless electrochemical mechanical polishing device for conductive porous hard Material workpiece
Fig. 1 is a schematic diagram of a wireless electrochemical mechanical polishing device for a conductive porous hard material workpiece according to the present invention: the polishing device comprises a polishing head (2), an electrically conductive porous hard material workpiece (3), a polishing pad (4), a polishing disk (5), a polishing liquid spray head (8), an electrically conductive slip ring (9), positive and negative electrodes (6), positive and negative electrode bus lines (7), a direct current power supply (10) and a polishing liquid recovery groove (1); the polishing pad is stuck to the bottom of the polishing disc; wherein the polishing pad and the polishing disk have through holes which are 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 upwards combined into a bus line at the top of the polishing disc, and the bus line is respectively connected with the positive and negative electrodes of the power supply through a conductive slip ring; a polishing pad is arranged below the electrode to separate the electrode from the conductive porous hard material workpiece; the conductive porous hard material workpiece is fixed on the polishing head: during processing, polishing liquid is dripped into the through hole and flows to the surface of the conductive porous hard material workpiece, the polishing disc or the polishing pad is pressed on the surface of the conductive porous hard material workpiece, the conductive porous hard material workpiece and the polishing pad or the polishing disc rotate in the same direction, and electrochemical mechanical polishing can be performed on the conductive porous hard material workpiece after voltage is applied.
In this embodiment, the conductive porous hard material workpiece to be processed is made of tungsten carbide/cobalt metal material, the diameter is 10 mm-204 mm, and YG8 tungsten carbide-cobalt cemented carbide is further preferred, and the diameter is 50.8mm.
In this embodiment, the polishing pad and the polishing disk are both made of an electrically insulating material, and more preferably, the SUBA800 polishing pad, and the polishing disk is made of polytetrafluoroethylene.
In this embodiment, the polishing pad and polishing disk each have through holes of the same diameter and arranged in a honeycomb array, the polishing pad and polishing disk have diameters of 20cm to 100cm, and each through hole has an area of 0.07cm 2 ～1cm 2 Further preferably, the diameter is 23cm, and each circular through hole has a diameter of 0.6cm.
In this embodiment, the thickness of the polishing pad is 2cm to 5cm, and more preferably 2.3cm.
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 of one or more of platinum, tantalum, ruthenium, iridium or niobium, and more preferably platinum metal.
In the embodiment, the positive and negative electrodes are in the shape of one or more of a disk, a wire or a sheet, and the electrode area is 0.1mm 2 ～10mm 2 Further, a wire electrode is preferable, and a diameter of 0.3mm and a length of 2mm are preferable.
In this embodiment, the positive and negative electrodes are incorporated into the bus line and connected to the positive and negative ends of the power supply via the conductive slip ring, and the conductive connection is made of a conductive wire wrapped with a waterproof insulating layer, preferably a copper conductive wire wrapped with polytetrafluoroethylene, and more preferably a copper conductive diameter of 0.5mm.
In this embodiment, the pressure at which the bottom of the polishing disc is pressed against the conductive porous hard material workpiece is 4psi to 8psi. More preferably 5 to 7psi.
In this embodiment, the dropping speed of the polishing liquid into the through hole is 50mL/min to 120mL/min, and more preferably 100mL/min.
In this embodiment, the pH of the polishing liquid is 1 to 13, the conductivity is 0.5s/m to 2s/m, more preferably 9 to 13, the conductivity is 0.5s/m to 1s/m, still more preferably 12, and the conductivity is 0.8s/m.
In this embodiment, the voltage applied to each cell is 5V to 60V, more preferably 30V to 50V.
In this embodiment, the rotation speed at which the electrically conductive porous hard material and the polishing pad or the polishing disk are rotated in the same direction is 50rpm to 300rpm, and more preferably 200rpm.
Fig. 2 is a schematic view of the structure of the electrochemical cell at the bottom of the through hole of the polishing disc: two metal platinum wires with the diameter of 0.3mm are vertically arranged at the bottom of each through hole of the polishing disk and are respectively fixed at two ends of the diameter of the through hole, and the platinum wire ends are consistent with the bottom surface of the polishing disk; bonding the conductive adhesive with a polytetrafluoroethylene-coated copper wire, and coating the platinum wire and the conductive bonding part with epoxy adhesive, wherein each platinum wire only exposes 2mm wire ends; the copper wire is integrated into the bus line at the top of the polishing disk and connected to the positive and negative ends of the power supply through the conductive slip ring.
Example 2
Processing a conductive porous hard material workpiece by using the conductive porous hard material wireless electrochemical mechanical polishing device in the embodiment 1, wherein a polishing disc (thickness of 2.0 cm) and a polishing pad (SUBA 800) with diameters of 23cm are selected, and 131 through holes with diameters of 0.6cm are distributed according to a fibonacci array; the electrochemical cell structure used was identical to that described in example 1. The method for wireless electrochemical mechanical polishing of the conductive porous hard material workpiece comprises the following specific steps: YG8 tungsten carbide-cobalt (1.5 mm thick, 50.8cm diameter) was fixed to the polishing head with wax, with a pressure of 5psi between the polishing disc and the workpiece; the polishing solution had a pH of 5 and contained 10wt% Al having an average diameter of 50nm 2 O 3 Abrasive particles and 0.01MCoSO 4 The method comprises the steps of carrying out a first treatment on the surface of the Continuously dripping the polishing solution to the polishing disc at the dripping speed of 100ml/min, and electrifying a motor to ensure that the polishing disc and a workpiece fixed on the polishing head rotate in the same direction at the rotating speed of 200 rpm; and (3) turning on a power supply, applying a direct-current voltage of 15V to all electrochemical cells, and starting polishing. After processing for 0.5 hour, the power supply, the motor and the liquid supply system are sequentially turned off; removing the polishing head, taking out the workpiece, sequentially cleaning with de-waxing water, ethanol and ultrapure water, and dissolving Al in 0.1mol/L KOH for 2min by ultrasonic treatment 2 O 3 Nanoparticle, again via megasonicAfter 5 minutes of seed sowing in the ultra-pure water bath, nitrogen is blown to dry. The reduction of the weight of the hard alloy of the workpiece after processing is measured by adopting a high-precision balance with the precision of one ten thousandth, the material removal rate of processing is calculated to be 0.32 mu m/min from the density and the surface area of YG8 tungsten carbide, and the processing efficiency is greatly improved; the shape analysis laser confocal microscope (shown in fig. 3) showed that the surface roughness Sa of the processed surface was 84.6nm, and the method used could give a flat surface.
Example 3
Tungsten carbide-cobalt cemented carbide workpieces (50.8 cm diameter and 1.5mm thickness) were processed using the conductive porous hard material wireless electrochemical mechanical polishing apparatus described in example 1. The parts were mounted in the corresponding locations according to the schematic diagram of the tooling used in fig. 1, with a pressure of 7.5psi between the polishing disc and the cemented carbide. Continuously dripping the polishing solution at a dripping speed of 100mL/min to a polishing disk, wherein the pH value of the polishing solution is 10, and the polishing solution contains 10wt% of diamond abrasive particles with an average diameter of 25nm and 0.001MCoSO 4 The method comprises the steps of carrying out a first treatment on the surface of the Energizing a motor to enable the polishing disc and a workpiece fixed on the polishing head to rotate in the same direction at a rotating speed of 204 rpm; and (3) turning on a power supply, applying a direct-current voltage of 10V to all electrochemical cells, and starting polishing. After processing for 0.5 hour, the power supply, the motor and the liquid supply system are sequentially turned off; removing the polishing head, taking out the tungsten carbide workpiece, cleaning the tungsten carbide workpiece by using wax removing water, ethanol and ultrapure water in sequence, removing diamond abrasive particles by using ultrasonic waves in 0.1mol/L KOH for 2min, and drying by using nitrogen after 5 minutes of ultra-pure water bath of megasonic waves. Measuring the reduction of the weight of the machined hard alloy by adopting a high-precision balance with the precision of one ten thousandth, and calculating the machined material removal rate of 0.513 mu m/min from the density and the surface area of the hard alloy; the processing efficiency is greatly improved; the shape analysis laser confocal microscope (fig. 4) showed that the surface roughness Sa of the processed surface was 67.1nm, which can give a flat surface.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for conducting porous hard material wireless electrochemical mechanical polishing is characterized by comprising the following specific steps:
fixing the conductive porous hard material workpiece on a polishing head;
processing the polishing pad and the polishing disk into a through hole structure with honeycomb array arrangement;
pasting polishing pads and polishing discs with the same size in a mode that through holes are overlapped;
a pair of positive and negative electrodes are arranged on the bottom wall of the through hole, are integrated into a bus line at the top of the polishing disk, and are then connected with the positive and negative electrodes of a power supply through a conductive slip ring;
in the polishing process, the positive electrode and the negative electrode are separated from the surface of the conductive porous hard material workpiece by the polishing pad, polishing liquid passes through the through holes and is dripped on the surface of the conductive porous hard material workpiece to form a polishing liquid layer, and the electrode and the polishing liquid layer form an electrolytic cell;
in the polishing process, the conductive porous hard material workpiece and the polishing pad or the polishing disk rotate in the same direction, electrochemical oxidation and electrochemical reduction reactions are simultaneously carried out at different positions on the surface of the conductive porous hard material workpiece in the electrolytic cell after voltage is applied, and the electrochemical process and the mechanical friction removal process are uniformly and alternately carried out.
2. A method of wireless electrochemical mechanical polishing of an electrically conductive porous hard material as in claim 1, wherein: the dropping speed of the polishing solution into the through hole is 10-120 mL/min; the saidThe pH value of the polishing solution is 1-13, and the polishing solution contains 0.001-0.01M CoSO 4 Solutions or NiSO 4 A solution.
3. A method of wireless electrochemical mechanical polishing of an electrically conductive porous hard material as in claim 1, wherein: the applied voltage is 5V-60V.
4. A method of wireless electrochemical mechanical polishing of an electrically conductive porous hard material as in claim 1, wherein: the conductive porous hard material is a composite material prepared by sintering one of tungsten carbide, silicon nitride or boron nitride hard powder material and one of metallic nickel, chromium or cobalt at high temperature.
5. The wireless electrochemical mechanical polishing device for the conductive porous hard material is characterized by comprising a polishing head, a conductive porous hard material workpiece, a polishing disk, a polishing pad, positive and negative electrode bus lines, a conductive slip ring, a direct current power supply, a polishing solution spray head and a polishing solution recovery tank; wherein, the polishing disk and the polishing pad are provided with through holes which are arranged in a honeycomb array; the polishing pad holding through holes are correspondingly stuck to the bottom of the polishing disc; positive and negative electrode bus lines are arranged at the top of the polishing disk, the bus lines are connected to the direct current power supply through the conductive slip rings, and the bus lines are converged into the side wall of the bottom of the polishing disk to form the positive and negative electrodes of the electrolytic cell; the positive and negative electrodes are separated from the conductive porous hard material workpiece by a polishing pad.
6. The conductive porous hard material wireless electrochemical mechanical polishing device of claim 5, wherein: the diameter of the conductive porous hard material is 20 mm-204 mm.
7. The conductive porous hard material wireless electrochemical mechanical polishing device of claim 5, wherein: the polishing pad and the polishing disk have the same diameter, and the diameter is 20 cm-100 cm; the polishing pad and the polishing disk are arranged in a honeycomb arrayThrough holes with an area of 0.07cm 2 ～1cm 2 The method comprises the steps of carrying out a first treatment on the surface of the The polishing pad and the polishing disk are made of electrically insulating materials; the thickness of the polishing disc is 2 cm-5 cm.
8. The conductive porous hard material wireless electrochemical mechanical polishing device of claim 5, wherein: the electrode material of the positive and negative electrodes is an alloy formed by one or more of platinum, tantalum, ruthenium, iridium or niobium.
9. The conductive porous hard material wireless electrochemical mechanical polishing device of claim 5, wherein: the area of the positive electrode and the negative electrode is 0.1mm 2 ～10mm 2 The shape of the electrode is one or more of sheet, linear, disk or combination.
10. The apparatus for wireless electrochemical mechanical polishing of an electrically conductive porous hard material of claim 5, wherein: the bus line is a wire wrapped by a waterproof insulating layer.
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