A method of chemical vapor deposition of polycrystalline diamond by liquid steel erosion polishing

Abstract

The application provides a chemical vapor deposition polycrystalline diamond steel liquid erosion polishing method and relates to the technical field of diamond material processing. The chemical vapor deposition polycrystalline diamond steel liquid erosion polishing method places steel material with a carbon content of 0-0.77% and a weight of 0.1-5 kg in a ceramic crucible, uses inductive coupling to heat the steel material to 1400-1800 DEG C and controls the liquid surface to be stable, uses a motion controller with a moving control precision of not more than 0.02 mm to immerse the sample in the steel liquid for 0.1 s-10 min and then take out the sample, and carbon atoms constituting the sample are dissolved and diffused into the steel liquid under the action of the steel liquid erosion, so that the sample surface is rapidly flattened. The method has the advantages that a new way is provided for realizing high-speed, high-yield and high-throughput polishing processing of chemical vapor deposition polycrystalline diamond.

Description

Technical Field

[0001] This invention relates to the field of diamond material processing technology, specifically to a method for molten steel erosion polishing of polycrystalline diamond by chemical vapor deposition. Background Technology

[0002] Currently, industrially produced chemical vapor deposition (CVD) polycrystalline diamond disks can reach diameters of up to 8 inches, showing broad application prospects in fields such as electronic countermeasures, coating windows, acoustic wave transmission, and channel heat dissipation. However, the surface of CVD polycrystalline diamond exhibits complex and sharp facets, requiring polishing before further application. Diamond's status as the hardest natural material makes polishing extremely difficult; current industrial polishing methods for CVD polycrystalline diamond samples often take tens of hours. Furthermore, most industrial polishing methods rely on mechanical grinding to remove polycrystalline diamond, which easily induces internal stress buildup, leading to cracking and scrapping, significantly increasing industrial costs. In addition, there are almost no reports of high-throughput CVD polycrystalline diamond processes, both domestically and internationally. Therefore, a new high-rate, high-yield, and high-throughput polishing process for CVD polycrystalline diamond is urgently needed.

[0003] In thermochemical polishing techniques, methods for polishing chemical vapor deposition (CVD) polycrystalline diamond using hot iron plates at 500-800℃ have been reported. However, methods for polishing CVD polycrystalline diamond using molten steel erosion have not been reported. Molten steel, as a liquid metal, has an erosive effect on the sample. This effect is gentler and faster than industrial mechanical grinding. During polishing, carbon atoms dissolve and diffuse into the molten steel under the erosive action, rapidly smoothing the sample surface. This effectively reduces polishing time and does not cause sample cracking. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a steel molten metal erosion polishing method for chemical vapor deposition of polycrystalline diamond, which can achieve high-speed, high-yield, and high-throughput polishing of chemical vapor deposition of polycrystalline diamond.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: a method for steel liquid erosion polishing of chemical vapor deposition polycrystalline diamond, comprising a polishing device, and polishing the chemical vapor deposition polycrystalline diamond sample through the polishing device;

[0008] The polishing device includes a chemical vapor deposition polycrystalline diamond sample, an inorganic curing material, a ceramic rod, a motion controller, an inductively coupled heating power supply, an inductively coupled heating coil, steel material, a ceramic crucible, a ceramic gasket, a stainless steel water-cooled reaction chamber, gas pipelines, a vacuum pump, and a protective gas cylinder.

[0009] The steel molten metal erosion and polishing method includes the following steps:

[0010] Step 1: Preparation of Inorganic Curing Materials

[0011] Inorganic curing material can be obtained by uniformly mixing polymer liquid and aluminosilicate powder in a weight ratio of 1:2.

[0012] Step 2: Bonding the sample:

[0013] The two ends of the above inorganic curing material were bonded to a chemical vapor deposition polycrystalline diamond sample and a ceramic rod, respectively. After bonding, the material was cured at room temperature for 0.1-24 hours, and then placed on a heating table at 60-120℃ for 0.1-2 hours to ensure a firm bond.

[0014] Step 3: Obtaining molten steel:

[0015] Steel with a carbon content of 0-0.77% and a weight of 0.1-5kg is placed in a ceramic crucible. The gas cylinder is opened to allow argon gas to enter the stainless steel water-cooled reaction chamber. A vacuum pump is used to evacuate the gas to a level below 10KPa. The steel is then heated to 1400-1800℃ using an inductively coupled heating power supply to obtain molten steel.

[0016] Step 4: Etching and Polishing

[0017] Using a motion controller with a motion control accuracy of no more than 0.02 mm, the chemical vapor deposition (CVD) polycrystalline diamond sample is immersed in molten steel to a depth twice the surface roughness of the CVD polycrystalline diamond sample. After erosion and polishing time, the CVD polycrystalline diamond sample is slowly lifted into the argon environment in the stainless steel water-cooled reaction chamber and left to stand for 1-5 minutes before being lifted into the atmospheric environment.

[0018] Preferably, the chemical vapor deposition polycrystalline diamond sample is connected to the ceramic rod disposed above it using an inorganic curing material.

[0019] Preferably, the ceramic rod is brazed to a motion controller disposed above it.

[0020] Preferably, the ceramic crucible containing the steel is placed above the ceramic pad, and the steel is positioned in the center of the inductively coupled heating coil and is in a horizontal state by adjusting the ceramic pad.

[0021] Preferably, the stainless steel water-cooled reaction chamber is provided with multiple sealing gaskets, and the motion controller, gas pipeline and inductively coupled heating coil are fixed in the stainless steel water-cooled reaction chamber through the sealing gaskets.

[0022] Preferably, the original surface roughness of the chemical vapor deposition polycrystalline diamond sample does not exceed 100 μm.

[0023] Preferably, the motion control accuracy of the motion controller is no greater than 0.02 mm.

[0024] Preferably, the vacuum degree of the stainless steel water-cooled reaction chamber is less than 10 kPa.

[0025] Preferably, the heating power of the inductively coupled heating power supply is 1-50kW, and the heating frequency of the inductively coupled heating power supply is 1-100kHz.

[0026] Preferably, the immersion rate of the chemical vapor deposition polycrystalline diamond sample is 0.001-0.5 mm / s, and the erosion and polishing time is 0.1 s-10 min.

[0027] (III) Beneficial Effects

[0028] This invention provides a method for erosion polishing of polycrystalline diamond using molten steel via chemical vapor deposition. It offers the following advantages:

[0029] 1. This invention can achieve high-speed, high-yield, and high-throughput polishing of polycrystalline diamond.

[0030] 2. This invention originally proposes a method for polishing chemical vapor deposition (CVD) polycrystalline diamond using molten steel erosion. Molten steel, as a liquid metal, has an erosive effect on CVD polycrystalline diamond. This effect is gentler than industrial mechanical grinding, preventing cracking of the CVD polycrystalline diamond and significantly reducing costs. During polishing, carbon atoms dissolve and diffuse into the molten steel under the erosive action, rapidly smoothing the sample surface. Compared to the tens of hours required for polishing industrial CVD polycrystalline diamond polishing methods, this invention significantly reduces production time. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 This is a scanning electron microscope image of a polycrystalline diamond sample deposited by chemical vapor deposition before polishing by molten steel in Embodiment 1 of the present invention.

[0033] Figure 3This is a scanning electron microscope image of a chemical vapor deposition polycrystalline diamond sample after steel molten erosion and polishing, according to Embodiment 1 of the present invention.

[0034] Figure 4 X-ray diffraction patterns of chemical vapor deposition polycrystalline diamond samples before and after polishing by molten steel erosion, according to Embodiment 1 of the present invention.

[0035] Figure 5 An atomic force microscope image of a chemical vapor deposition polycrystalline diamond sample after steel erosion and polishing according to Embodiment 1 of the present invention;

[0036] Figure 6 This is a scanning electron microscope image of a polycrystalline diamond sample deposited by chemical vapor deposition before polishing by molten steel in Embodiment 2 of the present invention.

[0037] Figure 7 This is a scanning electron microscope image of a chemical vapor deposition polycrystalline diamond sample after steel molten erosion and polishing, as shown in Example 2 of the present invention.

[0038] Figure 8 X-ray diffraction patterns of polycrystalline diamond samples deposited by chemical vapor deposition before and after polishing by molten steel erosion, as shown in Embodiment 2 of the present invention.

[0039] Figure 9 An atomic force microscope image of a chemical vapor deposition polycrystalline diamond sample after steel molten erosion and polishing, as shown in Embodiment 2 of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1:

[0042] like Figure 1 As shown, this embodiment of the invention provides a method for molten steel erosion polishing of chemical vapor deposition (CVD) polycrystalline diamond, including a polishing device, and polishing the CVD polycrystalline diamond sample using the polishing device.

[0043] The polishing apparatus includes a chemical vapor deposition (CVD) polycrystalline diamond sample 1, an inorganic curing material 2, a ceramic rod 4, a motion controller 3, an inductively coupled heating power supply 6, an inductively coupled heating coil 5, a sealing gasket 7, steel material 9, a ceramic crucible 10, a ceramic gasket 8, a stainless steel water-cooled reaction chamber 11, gas pipelines 12, a vacuum pump 13, and a protective gas cylinder 14. The CVD polycrystalline diamond sample 1 is connected to the ceramic rod 4 above it using the inorganic curing material 2. The ceramic rod 4 is brazed to the motion controller 3 above it for easy connection. The system enables the clamping and precise vertical transport of polycrystalline diamond sample 1 obtained by chemical vapor deposition, achieving a transport spatial resolution of 5 μm. A ceramic crucible 10 containing steel material 9 is placed above a ceramic pad 8, and the steel material 9 is positioned at the center of the inductively coupled heating coil 5 and kept horizontal by adjusting the ceramic pad 8. A stainless steel water-cooled reaction chamber 11 is arranged on the periphery, and multiple sealing gaskets 7 are arranged on the reaction chamber for clamping and transporting the polycrystalline diamond sample 1 obtained by chemical vapor deposition, placing the gas pipeline 12, and placing the heating coil 5, respectively.

[0044] like Figure 2 As shown, the chemical vapor deposition polycrystalline diamond sample 1 is a circular film with a diameter of 1.5 cm, a thickness of 1.05 mm, and a surface roughness of 30 μm, exhibiting a crystal orientation in which the (220) plane is dominant and a small number of (111) planes coexist.

[0045] The steel molten metal erosion polishing method includes the following steps:

[0046] Step 1: Preparation of Inorganic Curing Material 2:

[0047] Inorganic curing material 2 can be obtained by mixing the polymer liquid and aluminosilicate powder in a weight ratio of 1:2.

[0048] Step 2: Bonding the sample:

[0049] The two ends of the inorganic curing material 2 were respectively bonded to the chemical vapor deposition polycrystalline diamond sample 1 and the ceramic rod 4. After bonding, the material was cured at room temperature for 24 hours and then placed on a heating table at 120°C for 2 hours to ensure a firm bond.

[0050] Step 3: Obtaining molten steel:

[0051] Steel material 9 with a carbon content of 0.003% and a weight of 0.5 kg is placed in a ceramic crucible 10. Argon is used as a protective gas. The protective gas cylinder 14 is opened to allow argon to enter the stainless steel water-cooled reaction chamber 11. A vacuum pump 13 is used to evacuate to 1 Pa. The steel material 9 is heated to 1600°C using an inductively coupled heating power supply 6 with a heating power of 25 kW and a heating frequency of 80 kHz to obtain molten steel. The liquid level of the molten steel is controlled to be in a stable state.

[0052] Step 4: Etching and Polishing

[0053] Using motion controller 3, the chemical vapor deposition (CVD) polycrystalline diamond sample 1 was immersed in molten steel to a depth of 60 μm at a speed of 0.006 mm / s. A stopwatch was used to time the immersion. After 10 seconds, the CVD polycrystalline diamond sample 1 was slowly lifted into the protective gas environment of the stainless steel water-cooled reaction chamber 11 and left to stand for 1 minute before being released into the atmosphere. Figure 3 As shown.

[0054] like Figure 4 As shown, the X-ray diffraction pattern shows that after steel liquid erosion and polishing, the surface crystal orientation of the chemical vapor deposition polycrystalline diamond sample 1 is almost entirely transformed to the (220) plane.

[0055] like Figure 5 As shown in the atomic force microscopy image, the surface roughness of the chemical vapor deposition polycrystalline diamond sample 1 decreased to 5.62 nm after steel molten erosion and polishing.

[0056] Example 2:

[0057] The difference between this embodiment and Embodiment 1 is that:

[0058] like Figure 6 As shown, the chemical vapor deposition polycrystalline diamond sample 1 is a circular film with a diameter of 1.5 cm, a thickness of 1.054 mm, and a surface roughness of 30 μm, exhibiting a crystal orientation in which the (220) plane is dominant and a small number of (111) and (311) planes coexist.

[0059] The steel molten metal erosion polishing method includes the following steps:

[0060] Step 1: Preparation of Inorganic Curing Material 2:

[0061] Inorganic curing material 2 can be obtained by mixing the polymer liquid and aluminosilicate powder in a weight ratio of 1:2.

[0062] Step 2: Bonding the sample:

[0063] The two ends of the inorganic curing material 2 were respectively bonded to the chemical vapor deposition polycrystalline diamond sample 1 and the ceramic rod 4. After bonding, the material was cured at room temperature for 24 hours and then placed on a heating table at 120°C for 2 hours to ensure a firm bond.

[0064] Step 3: Obtaining molten steel:

[0065] A steel material 9 with a carbon content of 0.45% and a weight of 1 kg is placed in a ceramic crucible 10. Argon is used as a protective gas. The protective gas cylinder 14 is opened to allow argon to enter the stainless steel water-cooled reaction chamber 11. A vacuum pump 13 is used to evacuate to 1 Pa. An inductively coupled heating power supply 6 is used to heat the steel material 9 to 1550°C with a heating power of 20 kW and a heating frequency of 10 kHz to obtain molten steel. The liquid level of the molten steel is controlled to be in a stable state.

[0066] Step 4: Etching and Polishing

[0067] Using motion controller 3, the chemical vapor deposition (CVD) polycrystalline diamond sample 1 was immersed in molten steel to a depth of 60 μm at a speed of 0.006 mm / s. A stopwatch was used to time the immersion. After 1 minute, the CVD polycrystalline diamond sample 1 was slowly lifted into the protective gas environment of the stainless steel water-cooled reaction chamber 11 and left to stand for 1 minute before being released into the atmospheric environment. Figure 7 As shown.

[0068] like Figure 8 As shown, the X-ray diffraction pattern shows that after steel liquid erosion and polishing, the surface crystal orientation of the chemical vapor deposition polycrystalline diamond sample 1 is almost entirely transformed to the (220) plane.

[0069] like Figure 9 As shown in the atomic force microscopy image, the surface roughness of the chemical vapor deposition polycrystalline diamond sample 1 decreased to 6.01 nm after steel molten erosion and polishing.

[0070] In summary, a steel molten metal erosion polishing method for chemical vapor deposition (CVD) polycrystalline diamond can achieve high-speed, high-yield, and high-throughput polishing of polycrystalline diamond. This invention originally proposes a method for polishing CVD polycrystalline diamond using steel molten metal erosion. As a liquid metal, steel molten metal has an erosive effect on CVD polycrystalline diamond, which is gentler than industrial mechanical grinding. Carbon atoms dissolve and diffuse into the steel molten metal under the erosive action, preventing cracking of the CVD polycrystalline diamond and significantly reducing cost losses. Compared to the tens of hours of polishing time required by industrial CVD polycrystalline diamond polishing methods, this invention greatly reduces production time.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of chemical vapor deposition polycrystalline diamond, steel liquid erosion polishing, characterized in that: The polishing device is used for polishing the chemical vapor deposition polycrystalline diamond sample. The polishing device comprises a chemical vapor deposition polycrystalline diamond sample (1), an inorganic solidified material (2), a ceramic rod (4), a motion controller (3), an inductive coupling heating power supply (6), an inductive coupling heating coil (5), a sealing gasket (7), a steel material (9), a ceramic crucible (10), a ceramic gasket (8), a stainless steel water-cooled reaction cavity (11), a gas pipeline (12), a vacuum pump (13), and a protective gas cylinder (14). The steel liquid erosion polishing method comprises the following steps. Step one: preparation of the inorganic solidified material (2) The high molecular polymer liquid and the silico-aluminate powder are mixed uniformly at a weight ratio of 1:2 to obtain the inorganic solidified material (2). Step two: bonding of the sample The two ends of the inorganic solidified material (2) are respectively bonded with the chemical vapor deposition polycrystalline diamond sample (1) and the ceramic rod (4), and after the bonding is completed, the sample is cured at room temperature for 0.1-24 hours, and then placed on a heating table at 60-120 DEG C for heating for 0.1-2 hours to ensure firm bonding. Step three: obtaining of the steel liquid The steel material (9) with a carbon content of 0-0.77% and a weight of 0.1-5 kg is placed in the ceramic crucible (10), the protective gas cylinder (14) is opened, the protective gas is introduced into the stainless steel water-cooled reaction cavity (11), the vacuum pump (13) is used to draw a vacuum to less than 10 KPa, and the inductive coupling heating power supply (6) is used to heat the steel material (9) to 1400-1800 DEG C to obtain the steel liquid. Step four: erosion polishing The motion controller (3) with a movement control precision of not more than 0.02 mm is used to immerse the chemical vapor deposition polycrystalline diamond sample (1) into the steel liquid, the immersion depth is 2 times the surface roughness of the chemical vapor deposition polycrystalline diamond sample (1), after the erosion polishing, the chemical vapor deposition polycrystalline diamond sample (1) is slowly taken out to the protective gas environment in the stainless steel water-cooled reaction cavity (11) and is placed for 1-5 minutes, and then is taken out to the atmospheric environment.

2. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing method. The chemical vapor deposition polycrystalline diamond sample (1) is connected with the ceramic rod (4) arranged above the chemical vapor deposition polycrystalline diamond sample (1) by the inorganic solidified material (2).

3. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing method. The ceramic rod (4) is brazed with the motion controller (3) arranged above the ceramic rod (4).

4. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing method. The ceramic crucible (10) containing the steel material (9) is arranged above the ceramic gasket (8), and the steel material (9) is arranged in the central position of the inductive coupling heating coil (5) and in a horizontal state by adjusting the ceramic gasket (8).

5. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing method. The stainless steel water-cooled reaction cavity (11) is provided with a plurality of sealing gaskets (7), and the stainless steel water-cooled reaction cavity (11) is fixed with the motion controller (3), the gas pipeline (12) and the inductive coupling heating coil (5) through the sealing gaskets (7).

6. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing method. The original surface roughness of the chemical vapor deposition polycrystalline diamond sample (1) is not more than 100 μm.

7. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing method. The movement control precision of the motion controller (3) is not more than 0.02 mm.

8. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing. The vacuum degree of the stainless steel water-cooled reaction cavity (11) is less than 10 KPa.

9. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing. The heating power of the inductive coupling heating power supply (6) is 1-50 kW, and the heating frequency of the inductive coupling heating power supply (6) is 1-100 kHz.

10. The method of claim 1, wherein the method is a chemical vapor deposition of polycrystalline diamond with a liquid steel erosion polishing. The immersion speed of the chemical vapor deposition polycrystalline diamond sample (1) is 0.001-0.5 mm / s, and the time of the erosion polishing is 0.1 s-10 min.

Images