CVD (Chemical Vapor Deposition) diamond compact, thrust bearing and manufacturing method thereof

Abstract

The invention provides a CVD diamond compact, a thrust bearing and a manufacturing method of the thrust bearing, and belongs to the technical field of thrust bearings. The CVD diamond is used as a composite sheet of the thrust bearing. According to the invention, the CVD diamond compact is selected to replace a traditional PDC compact, the abrasive ratio is up to 7130000, the wear resistance is extremely high, the damage to working parts can be effectively reduced, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of thrust bearings, and in particular to the application of CVD diamond in a composite sheet of a thrust bearing, the composite sheet of a thrust bearing, a thrust bearing comprising the composite sheet, and a method for manufacturing the thrust bearing. Background Art

[0002] Polycrystalline Diamond Composite (PDC) thrust bearings are one of the key components of turbodrills, screw drills, rotary steerable drills and submersible pumps, and are widely used in geological drilling and oil drilling. PDC thrust bearings consist of a stationary bearing ring (stator) and a rotating bearing ring (rotor). The bearing rings are embedded with evenly distributed PDC composite sheets, and the PDC surfaces on the two rings rub to withstand thrust loads.

[0003] During the drilling process, most of the support bearings of screw drill tools adopt open structures, which are faced with extremely harsh working conditions such as high temperature, high pressure, friction, vibration, impact, corrosion, etc., which can easily cause PDC failures such as wear, thermal damage, breakage and shedding. During the operation of radial bearings, there is sliding friction contact between the moving ring and the fixed ring. Under heavy load and high speed conditions, the PDC thrust bearing generates serious friction heat, which will cause friction wear failure and thermal damage. The cracks generated by PDC thermal damage interact with each other to form an intricate crack network. As the working time of the PDC bearing continues, the diamond interacts with the binder (Co), the degree of cracking and graphitization deepens, the number of cracks increases, and the size increases. Under the action of friction, a large number of diamonds fall off the PDC surface, the number of pits on the PDC surface increases, the roughness increases, the friction coefficient increases, the friction heat is aggravated, and the thermal damage is aggravated, leading to a vicious cycle; on the other hand, the microcracks merge and connect, and under the action of extremely large contact pressure and impact force, large pieces of diamond eventually collapse from the PDC, the polycrystalline diamond composite sheet is significantly damaged, and large pieces of the edge peel off, which seriously limits the service life. Therefore, finding other diamonds to replace PDC, improving the thermal stability between the friction pairs of diamond thrust bearings, and increasing the service life of thrust bearings have become technical problems that need to be solved in the field of diamond thrust bearings.

[0004] CVD diamond is an artificial diamond made by chemical vapor deposition process. It has many excellent physical and chemical properties, including extremely high hardness and wear resistance, extremely low friction coefficient, and the ability to maintain its performance stability in extreme environments. It can reduce the friction coefficient and increase the service life of the thrust bearing. In addition, CVD diamond has unique advantages such as high strength and corrosion resistance. It is a superhard material with excellent performance. No technicians have yet used CVD diamond as a composite sheet in traditional PDC thrust bearings. Summary of the invention

[0005] In view of this, in order to find other diamonds to replace the PDC thrust bearing composite sheets in the prior art, so as to improve the thermal stability between the diamond thrust bearing friction pairs and increase the service life of the thrust bearing, in the first aspect, the present invention provides the application of CVD diamond in the composite sheets of thrust bearings, and selects CVD diamond composite sheets to replace traditional PDC composite sheets. The wear ratio is as high as 713,000, it has extremely high wear resistance, can effectively reduce damage to working parts and increase service life.

[0006] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides the use of CVD diamond in a composite sheet of a thrust bearing.

[0007] In a second aspect, the present invention provides a composite sheet for a thrust bearing, wherein the composite sheet is a CVD diamond composite sheet.

[0008] Preferably, the CVD diamond composite sheet is welded in a hollow welding groove of the thrust bearing.

[0009] Preferably, the CVD diamond composite sheet is vacuum welded in the hollow welding groove by silver-copper-titanium solder.

[0010] Preferably, the vacuum degree of the vacuum welding is 2*10 -3 Pa, temperature is 850℃~880℃.

[0011] Preferably, the number of the CVD diamond compact is at least one.

[0012] Preferably, the number of the CVD diamond compacts is at least three.

[0013] Preferably, the CVD diamond composite sheet is in the shape of an irregular polygon or a cylinder; Preferably, the irregular polygon is a non-cylindrical shape composed of multiple tangent arc surfaces with different radius values; Preferably, the non-cylindrical shape is an elliptical column shape, a pea pod shape, or an olive shape.

[0014] In a third aspect, the present invention further provides a thrust bearing, comprising the composite sheet described above.

[0015] In a fourth aspect, the present invention further provides a method for manufacturing the thrust bearing, comprising the following steps: Step (1), making a base and a hollow welding groove; Step (2), preparing a CVD diamond composite sheet; Step (3), welding the CVD diamond composite sheet prepared in step (2) into the hollow welding groove prepared in step (1), thereby completing the preparation of the entire friction pair.

[0016] The CVD diamond composite sheet provided by the present invention and its application in the composite sheet of the thrust bearing selects the CVD diamond composite sheet to replace the traditional PDC composite sheet, and the wear ratio is as high as 713,000, which means that the CVD diamond composite sheet has higher wear resistance during use and can maintain good performance for a long time. Compared with the prior art, it has the following beneficial effects: High wear ratio: The wear ratio is as high as 713,000, which means that the CVD diamond composite sheet has higher wear resistance during use and can maintain good performance for a long time.

[0017] Extended service life: Due to its high wear resistance and impact resistance, CVD diamond composite sheets can significantly extend the service life of mechanical equipment and reduce the frequency of maintenance and replacement.

[0018] Improve work efficiency: Due to its high wear resistance, CVD diamond composite sheets can maintain efficient operation under more demanding working conditions, improving overall work efficiency.

[0019] Reduce replacement frequency: Compared with traditional materials, CVD diamond composite sheets reduce the frequent replacement caused by wear, reducing maintenance costs and downtime.

[0020] Stable performance: CVD diamond composite sheets can continue to provide stable performance during use, ensuring the efficiency and reliability of equipment operation.

[0021] Reduced failure rates: Higher wear resistance means fewer failures, which improves overall production efficiency.

[0022] Long-term cost savings: While the initial cost of CVD diamond compacts may be higher, their longer service life and lower maintenance costs result in a significantly lower total cost of ownership. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the thrust bearing structure of a single CVD diamond cylinder; Figure 2 It is a schematic diagram of the thrust bearing structure of multiple CVD diamond cylinders; Figure 3 It is a schematic diagram of the thrust bearing structure of multiple CVD diamond elliptical cylinders; Figure 4 It is a schematic diagram of the thrust bearing structure of multiple CVD diamond shaped columns; Figure 5The friction coefficient test curves of commercial polycrystalline diamond (PCD) and chemical vapor deposition diamond (CVD) used in the patent of this invention; Figure 6 The friction coefficient test curve of CVD diamond after adjusting the test parameters (test force set to 80 N, rotation speed set to 150 r / min); In the figure, 1. thrust bearing; 2. CVD diamond composite sheet; 3. base. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", "top / bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] like Figure 1-4 As shown, in a first aspect, the present invention provides the use of CVD diamond in a composite sheet of a thrust bearing 1 .

[0028] Limitations of traditional materials: Although traditional PDC (polycrystalline diamond composite) has high hardness and wear resistance, it still has certain limitations under extreme working conditions, such as rapid wear and limited life.

[0029] High-demand application scenarios: Thrust bearings are widely used in high-intensity and high-load industries such as oil drilling, mining, and wind power generation. These industries have higher requirements on the wear resistance and reliability of bearings.

[0030] To this end, the present invention proposes the use of CVD diamond in the composite sheet of the thrust bearing 1 .

[0031] Advantages of CVD Diamond High hardness and wear resistance: CVD diamond has extremely high hardness (Vickers hardness can reach 10,000 HV), and is one of the hardest materials in nature. This makes CVD diamond composite sheets exhibit excellent wear resistance during use.

[0032] Excellent thermal and chemical stability: CVD diamond can maintain good performance in high temperature, high pressure and corrosive environments, and will not degrade due to temperature changes or chemical erosion.

[0033] Low friction coefficient: CVD diamond has a smooth surface and low friction coefficient, which reduces friction loss and improves transmission efficiency.

[0034] Specific applications Thrust bearing composite sheet: Applying CVD diamond composite sheet to the core load-bearing components of thrust bearings can significantly improve the overall performance of the bearings.

[0035] Improved wear ratio: Experimental data show that the wear ratio of CVD diamond is as high as 713,000, while that of traditional PCD diamond is 216,000. This means that CVD diamond composite sheets made of CVD diamond can maintain good performance for a long time in actual use, reducing wear and replacement frequency.

[0036] Improve equipment reliability: Due to its excellent wear resistance and stability, CVD diamond composite sheets can effectively reduce the occurrence of bearing failures and improve the operating reliability and production efficiency of equipment.

[0037] Economic Benefits Reduced maintenance costs: Longer service life means lower maintenance costs and downtime, reducing the economic losses caused by frequent bearing replacement.

[0038] Improve return on investment: For high-intensity, high-load application scenarios, the use of CVD diamond composite sheets can bring higher return on investment and extend the life cycle of equipment.

[0039] Application scenario examples Oil drilling: In deep-sea drilling platforms, thrust bearings are subjected to tremendous pressure and complex environmental conditions. The application of CVD diamond composite sheets can ensure long-term stable operation of bearings and reduce the number of maintenance and replacements.

[0040] Mining: Mining equipment needs to work in harsh environments. The high wear resistance and corrosion resistance of CVD diamond composite sheets make them an ideal choice, which improves the service life and operating efficiency of the equipment.

[0041] Wind power generation: The main shaft bearings of wind turbines need to work under high load for a long time. The application of CVD diamond composite sheets can effectively improve the durability and reliability of bearings and reduce maintenance costs.

[0042] In a second aspect, the present invention provides a composite sheet of a thrust bearing 1, wherein the composite sheet is a CVD diamond composite sheet 2. The height of the CVD diamond composite sheet 2 is preferably 2 to 6 mm, and the diameter is preferably between 3 and 40 mm. The size of the CVD diamond composite sheet 2 is the size of the composite sheet required for the common thrust bearing on the market. Those skilled in the art can select it according to the actual application scenario. It is only an exemplary size. According to the actual application scenario, its size can be larger or smaller than the size listed in the present invention.

[0043] In the present invention, the CVD diamond composite sheet 2 is welded in the hollow welding groove of the thrust bearing 1 .

[0044] In the present invention, the CVD diamond composite sheet 2 is vacuum welded in the hollow welding groove by silver-copper-titanium solder.

[0045] In the present invention, the vacuum degree of the vacuum welding is 2*10 -3 Pa, the temperature is 850~880℃. The vacuum welding process is preferably: the vacuum degree is drawn to 2*10 -3 Pa, start heating, the heating chamber temperature reaches 850-880℃, keep warm for 15-30 minutes, then slowly cool to 200℃ at a rate of 2-5%℃ / min, and naturally cool to room temperature.

[0046] In the present invention, at least one CVD diamond composite sheet 2 is provided in the hollow welding groove, covering at most the entire edge of the friction pair.

[0047] In the present invention, the number of the CVD diamond compacts 2 is at least three.

[0048] In the present invention, the CVD diamond composite sheet 2 is cylindrical or irregular polygonal. The irregular polygon is preferably a non-cylindrical shape composed of multiple tangent arc surfaces with different radius values. More preferably, the non-cylindrical shape is an elliptical column shape, a pea pod shape, or an olive shape, which is not limited by geometric shape and quantity.

[0049] It should be noted that there is at least one CVD diamond composite sheet 2 in the hollow welding groove, and a plurality of cylindrical CVD diamond composite sheets 2 (such as Figure 1-2 As shown), it can also be a plurality of elliptical cylindrical CVD diamond composite sheets 2 (such as Figure 3As shown), it can also be a plurality of pod-shaped CVD diamond composite sheets 2 (such as Figure 4 As shown in the figure), or a plurality of CVD diamond composite sheets 2 of different shapes can be arranged in the hollow welding groove, such as a combination of an elliptical column and a cylindrical shape, a combination of an elliptical column and a cylindrical shape and a pod shape, etc. In other words, the number and shape of the CVD diamond composite sheets in the hollow welding groove are not limited.

[0050] The cutting edge of CVD diamond is chamfered (or blunted) to strengthen the edge, with the chamfer angle of 5-30° and the width of 0.05~0.5mm, which is consistent with the traditional PDC diamond composite sheet.

[0051] In a third aspect, the present invention provides a thrust bearing 1, comprising the above composite sheet. The CVD diamond composite sheet 2 is welded in a hollow welding groove on a base 3 of the thrust bearing 1. The base 3 is preferably a cemented carbide base, and the thickness is preferably between 5 and 40 mm.

[0052] In a fourth aspect, the present invention provides a method for manufacturing the thrust bearing, comprising the following steps: Step (1), manufacturing the base 3 and the hollow welding groove, preferably the material for manufacturing the base is YG6 cemented carbide, and the specified structure is machined by mechanical processing according to different radius values, with a thickness between 10 and 40 mm. A cylindrical hollow welding groove is machined along the edge by an electric spark method, and the geometric dimensions are consistent with the internal CVD diamond. The center distance of the hollow welding groove should not be less than the sum of the radial radii of two adjacent cylindrical CVD diamonds, and the inside is polished smooth.

[0053] Step (2), prepare a CVD diamond composite sheet 2, preferably select CVD diamond with a thickness of 2 to 6 mm, use laser processing to form a cylindrical or non-cylindrical special-shaped structure, and polish one end of the cylindrical or non-cylindrical special-shaped structure to be bright and the other end to be smooth. The height range of the cylindrical or non-cylindrical special-shaped structure can be between 2 and 6 mm, and the diameter of the cylindrical or non-cylindrical special-shaped structure can be between 3 and 10 mm. Ensuring a certain total welding area can effectively improve the welding strength between the CVD diamond and the base 3.

[0054] Step (3), welding the CVD diamond composite sheet 2 prepared in step (2) into the hollow welding groove prepared in step (1) to complete the preparation of the entire friction pair. Preferably, the two end faces of the cylindrical CVD diamond are respectively ground and polished, and the surface is cleaned and set aside. After cleaning the inner surface of the hollow welding groove of the base, an appropriate amount of silver-copper-titanium solder is placed, and then the CVD diamond is placed, ensuring that the polished surface is placed upward. Welding is performed under a high vacuum environment to prepare a complete initial sample of the CVD diamond assembly. The CVD diamonds welded inside are independent of each other. The initial sample after welding is further refined, that is, the edge is strengthened (chamfered), the chamfer angle is 5-30°, and the width is between 0.05~0.5mm. The treated diamond will have better impact resistance, reduce damage to working parts, and increase service life.

[0055] The metal alloy friction pair is grooved according to the geometric dimensions of the core component based on CVD diamond by using the electric spark drilling method. The number of core components should be greater than 3 and evenly distributed over the entire circumference of the friction pair. The core components are welded in the grooves by high-frequency welding to complete the production of the friction pair.

[0056] The technical solution of the present invention is clearly described in detail below in conjunction with specific embodiments.

[0057] Example 1 Step 1: Select CVD diamond with a thickness of more than 5mm, and use laser processing to make a cylindrical structure with a diameter of 30mm. The two end faces are ground on one side and polished on the other side to mirror level, and the diamond thickness is kept at 5mm. Figure 1 shown.

[0058] Step 2: Use YAG laser to cut the CVD diamond made in the first step into cylindrical teeth with a diameter of 30mm and a height of 5mm, and clean them.

[0059] Step 3: Use YG6 cemented carbide material as the base 3 blank of the cylinder to process a hollow cylindrical structure with a diameter of 30.1 mm and a thickness of 4.5 mm, leaving a certain operating space for subsequent fine processing. Finally, clean the inner walls of all hollow welding grooves. The outer diameter of the cylindrical base is 33 mm and the overall thickness is 6 mm.

[0060] Step 4: Pour an appropriate amount of silver-copper-titanium solder into the soldering tank, and place the cylindrical CVD diamond flat in the soldering tank. Place a 0.3mm thick alumina ceramic sheet on top of the entire CVD diamond, the size of the ceramic sheet completely covers the entire base, and place a 100g weight on top of the ceramic sheet, and then place the whole thing flat in the vacuum furnace.

[0061] Step 5: The vacuum degree of the furnace chamber reaches 2*10-3 Pa, slowly heat up to 850 °C, keep warm for 2 hours, cool naturally to room temperature, and then shut down.

[0062] Step 6: Take out the welded core components and use an ultra-fine diamond grinding wheel on a special grinder to completely remove the remaining ceramic material to ensure a smooth and clean surface.

[0063] Step 7: Use a special diamond grinder to chamfer the exposed side edge of the CVD diamond. The angle between the chamfer and the upper surface is 10°, and the chamfer width is 0.3mm. The production of the core force-bearing component is completed.

[0064] Step 8: Use the electric spark drilling method to open 8 grooves with the same geometric dimensions as the core force-bearing component on the surface of the friction pair, with a groove depth of 6 mm and a diameter of 33.2 mm. Add an appropriate amount of solder and weld the core component to the friction pair through high-frequency welding to complete the final production.

[0065] Step 9: Testing, marking and packaging.

[0066] Complete the production of thrust bearings of single CVD diamond cylinders, such as Figure 1 shown.

[0067] Example 2 Step 1: Select CVD diamond with a thickness of 5mm, and use laser processing to make a cylindrical structure with a diameter of 5mm. The two end faces are ground on one side and polished on the other side to a mirror finish, and the diamond thickness is kept at 5mm. Figure 2 shown.

[0068] Step 2: Use YAG laser to cut 3 cylinders with a diameter of 5mm and a height of 5mm from the CVD diamond made in the first step, and clean them.

[0069] Step 3: Use YG6 carbide material as the base blank to process three hollow cylindrical structures with a diameter of 5.1 mm and a thickness of 4.5 mm, leaving a certain operating space for subsequent fine processing. Finally, clean the inner walls of all hollow welding grooves. The base thickness is 6 mm.

[0070] Step 4: Pour an appropriate amount of silver-copper-titanium solder into the soldering tank, and place three cylindrical CVD diamond mirrors facing upwards into the three soldering tanks. Place a 0.3mm thick alumina ceramic sheet on top of the entire base, the size of the ceramic sheet completely covers the entire base, and place a 100g weight on top of the ceramic sheet, and then place the whole thing flat in the vacuum furnace.

[0071] Step 5: Same as step 5 of Example 1.

[0072] Step 6: Same as step 6 of Example 1.

[0073] Step 7: Same as step 7 of Example 1.

[0074] Step 8: Use the electric spark drilling method to open 8 grooves with the same geometric dimensions as the core force-bearing components on the surface of the friction pair, with a groove depth of 6 mm. Add an appropriate amount of solder and weld the core component to the friction pair by high-frequency welding to complete the final production.

[0075] Step 9: Same as step 9 of Example 1.

[0076] Completed the production of multiple CVD diamond cylindrical thrust bearings, such as Figure 2 shown.

[0077] Example 3 Step 1: Select CVD diamond with a thickness of more than 5mm, and use laser processing to make an elliptical cylinder structure. The long axis of the elliptical cylinder is 8mm, the short axis is 6mm, and the two end faces are ground on one side and polished on the other side to mirror level, and the diamond thickness is kept at 5mm. Figure 3 shown.

[0078] Step 2: Use YAG laser to cut the CVD diamond made in the first step into three elliptical cylinders with a long axis of 8mm, a short axis of 6mm, and a height of 5mm, and clean them.

[0079] Step 3: Use YG6 carbide material as the base blank and process it into 3 hollow elliptical cylinder structures. The long axis of the elliptical cylinder is 8.1mm, the short axis is 6.1mm, and the thickness is 4.5mm. Finally, clean the inner wall of all welding grooves. Figure 3 shown.

[0080] Step 4: Pour an appropriate amount of silver-copper-titanium solder into the soldering tank, and place three elliptical cylindrical CVD diamond mirrors facing upwards into the three soldering tanks. Place a 0.3mm thick alumina ceramic sheet on top of the entire base, the size of the ceramic sheet completely covers the entire base, and place a 100g weight on top of the ceramic sheet, and then place the whole thing flat in a vacuum furnace.

[0081] Step 5: Same as step 5 of Example 2.

[0082] Step 6: Same as step 6 of Example 2.

[0083] Step 7: Same as Step 7 of Example 2.

[0084] Step 8: Same as step 8 of Example 2.

[0085] Step 9: Same as step 9 of Example 2.

[0086] Completed the production of multiple CVD diamond elliptical thrust bearings, such as Figure 3 shown.

[0087] Example 4 Step 1: Select CVD diamond with a thickness of more than 5mm and use laser processing to produce special-shaped column structures (such as pod-shaped, olive-shaped, etc.).

[0088] Step 2: Use YAG laser to cut the CVD diamond made in the first step into the required special-shaped column structure.

[0089] Step 3: Use YG6 carbide material as the base blank to process three special-shaped column structure welding grooves of matching sizes.

[0090] Step 4: Pour an appropriate amount of silver-copper-titanium solder into the soldering tank, and place three special-shaped columnar CVD diamond mirrors facing upwards into the three soldering tanks. Place a 0.3mm thick alumina ceramic sheet on top of the entire base, the size of the ceramic sheet completely covers the entire base, and place a 100g weight on top of the ceramic sheet, and then place the whole thing flat in the vacuum furnace.

[0091] Step 5: Same as step 5 of Example 3.

[0092] Step 6: Same as step 6 of Example 3.

[0093] Step 7: Same as Step 7 of Example 3.

[0094] Step 8: Same as step 8 of Example 3.

[0095] Step 9: Same as step 9 of Example 3.

[0096] Completed the production of thrust bearings with multiple CVD diamond shaped columns, such as Figure 4 shown.

[0097] The purposes of the alumina ceramic sheets involved in the above-mentioned embodiments 1-4 are as follows: (1) Ensure that each CVD diamond cylinder is subjected to uniform pressure during welding. Prevent welding defects or CVD diamond damage caused by uneven local force.

[0098] (2) Alumina ceramic sheets can protect the mirror-polished surface of CVD diamond from direct contact and scratches. Maintain the high finish of the CVD diamond surface and avoid damage caused by direct contact with other materials. Avoid pollution from the external environment.

[0099] (3) Alumina ceramic sheets have good insulation properties and can play a role of isolation and insulation during high-temperature welding, preventing current from passing through CVD diamond and affecting welding quality. It improves the stability and safety of the welding process and avoids unnecessary electric sparks or short circuits.

[0100] (4) Alumina ceramic sheets have low thermal conductivity and can control the speed and direction of heat transfer to a certain extent. This prevents thermal stress damage to CVD diamond caused by excessive heating, ensures uniform temperature in the welding area, and reduces thermal deformation.

[0101] (5) The alumina ceramic sheet completely covers the entire base, which can help accurately position and fix the CVD diamond cylinder. Ensure that each CVD diamond cylinder is accurately positioned during the welding process to avoid displacement or deflection.

[0102] Comparative Example 1 Commercial polycrystalline diamond (PCD) was selected as a comparative example.

[0103] It should be noted that the performance of PDC diamond composite sheets and CVD diamond composite sheets is completely dependent on polycrystalline diamond (PCD) and chemical vapor deposition diamond (CVD). Therefore, polycrystalline diamond (PCD) and chemical vapor deposition diamond (CVD) are directly selected for performance testing, as follows: like Figure 5 The figure shows the friction coefficient test curves of commercial polycrystalline diamond (PCD) and chemical vapor deposition diamond (CVD) used in the present invention. A silicon carbide ball with a diameter of 4 mm was selected as the friction object, the test force was set to 60 N, and the rotation speed was 100 r / min. During the 600-second test period, the friction coefficients of the two diamonds gradually stabilized. According to the data, the friction coefficient of commercial PCD diamond is about 0.56, and the friction coefficient of CVD diamond is only 0.18. By comparison, it can be seen that the friction coefficient of CVD is about 30% of that of PCD diamond. A smaller friction coefficient is beneficial to reduce losses during the friction pair wear and extend the working life. This shows that CVD diamond is an ideal friction pair stress-bearing material.

[0104] like Figure 6 Figure 2 shows the friction coefficient test curve of CVD diamond after adjusting the test parameters (test force set to 80 N, rotation speed set to 150 r / min). From the results, we can further see that after stabilization, the friction coefficient of CVD diamond is about 0.19, which is consistent with the previous set of data, indicating that the friction coefficient of CVD diamond after polishing is relatively stable.

[0105] The wear ratio test of the two diamonds was conducted using a wear ratio tester (80 mesh, standard green silicon carbide grinding wheel), with the table swing speed of about 20 mm / s, the grinding wheel rotation speed of 25 m / s, and the grinding depth of 0.02 mm. The results show that the wear ratio of commercial PCD diamond is about 216,000, while the wear ratio of CVD diamond selected in this patent is as high as 713,000. Materials with high wear ratios have less wear during use, which can significantly improve the quality and service life of the friction pair.

[0106] From the above experiments, it can be seen that CVD diamond composite sheets can maintain good performance for a long time in actual use, reduce wear and replacement frequency, and improve the reliability of equipment.

[0107] The above are only preferred specific implementations of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and improved concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. Application of CVD diamond in composite sheets of thrust bearings.

2. A composite sheet of a thrust bearing, characterized in that: The composite sheet is a CVD diamond composite sheet.

3. A composite sheet for a thrust bearing according to claim 2, characterized in that: The CVD diamond composite sheet is welded in the hollow welding groove of the thrust bearing.

4. A composite sheet for a thrust bearing according to claim 3, characterized in that: The CVD diamond composite sheet is vacuum welded in the hollow welding groove by silver-copper-titanium solder.

5. The composite sheet of a thrust bearing according to claim 4, characterized in that: The vacuum degree of the vacuum welding is 2*10 -3 Pa, temperature is 850℃~880℃.

6. The composite sheet of a thrust bearing according to claim 3, characterized in that: The number of the CVD diamond compact is at least one.

7. A composite sheet for a thrust bearing according to claim 6, characterized in that: The number of the CVD diamond compacts is at least three.

8. A composite sheet for a thrust bearing according to any one of claims 2 to 7, characterized in that: The CVD diamond composite sheet is in an irregular polygonal or cylindrical shape; Preferably, the irregular polygon is a non-cylindrical shape composed of multiple tangent arc surfaces with different radius values; Preferably, the non-cylindrical shape is an elliptical column shape, a pea pod shape, or an olive shape.

9. A thrust bearing, characterized in that: A composite sheet comprising any one of claims 2 to 8.

10. The method for manufacturing a thrust bearing according to claim 9, characterized in that: The steps include: Step (1), making a base and a hollow welding groove; Step (2), preparing a CVD diamond composite sheet; Step (3), welding the CVD diamond composite sheet prepared in step (2) into the hollow welding groove prepared in step (1), thereby completing the preparation of the entire friction pair.

Images