A rare earth doped high performance polycrystalline diamond compact and a method of making the same

Abstract

This invention relates to the field of superhard material manufacturing technology, specifically to a rare-earth-doped high-performance polycrystalline diamond composite sheet and its preparation method. The composite sheet includes a cemented carbide matrix and a polycrystalline diamond layer sintered thereon. The polycrystalline diamond layer comprises diamond micron powder, a binder, and rare-earth additives. The rare-earth additives are one or more elements selected from neodymium, praseodymium, dysprosium, terbium, europium, samarium, yttrium, terbium, lanthanum, cerium, yttrium, and neodymium, or one or more of their oxides or carbides. The content of the rare-earth additives in the polycrystalline diamond layer is 0.1-5.0 wt%. This invention addresses the problem that in existing technologies, the bonding between diamond and binders such as cobalt is mainly physical encapsulation and weak chemical interaction, which can easily become a failure initiation point under high temperature, high pressure, or impact loads.

Description

Technical Field

[0001] This invention relates to the field of superhard material manufacturing technology, specifically to a rare earth-doped high-performance polycrystalline diamond composite sheet and its preparation method. Background Technology

[0002] Polycrystalline diamond composites (PDCs) are ultra-hard composite materials formed by sintering layers of diamond micropowder onto a cemented carbide matrix under ultra-high pressure and high temperature conditions. Their performance primarily depends on the direct bonding strength between diamond particles within the diamond layer and the interfacial bonding strength between the diamond and the binder metal (usually cobalt). However, traditional PDCs have the following inherent drawbacks:

[0003] Weak interfacial bonding: The bonding between diamond and binders such as cobalt is mainly physical encapsulation and weak chemical interaction, which can easily become the starting point of failure under high temperature, high pressure or impact load.

[0004] Poor thermal stability: At high temperatures, cobalt in the binder catalyzes the transformation of diamond into graphite, and microcracks are generated due to the mismatch in thermal expansion coefficients, leading to "thermal degradation". The long-term operating temperature limit of traditional high-end PDCs is usually around 900°C, and performance degrades sharply beyond this temperature.

[0005] Impurities: Impurities such as oxygen and hydrogen adsorbed on the surface of diamond micropowder, as well as impurity gases in the sintering environment, can hinder the formation of diamond-diamond bonds, affecting densification and strength. Although studies have attempted to add various additives, fundamentally strengthening the interface, purifying the environment, and significantly improving overall performance, especially by simultaneously and substantially enhancing wear resistance and heat resistance, remains a critical technological bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0006] The purpose of this invention is to provide a high-performance polycrystalline diamond composite sheet with rare earth doping and its preparation method, which solves the problem that in the prior art, the bonding between diamond and binders such as cobalt is mainly physical encapsulation and weak chemical interaction, which is prone to becoming the failure starting point under high temperature, high pressure or impact load.

[0007] To solve the above-mentioned technical problems, the first technical solution adopted by the present invention is as follows:

[0008] A high-performance polycrystalline diamond composite sheet doped with rare earth elements includes a cemented carbide matrix and a polycrystalline diamond layer sintered thereon. The polycrystalline diamond layer contains diamond micropowder, a binder, and rare earth additives. The rare earth additives are one or more of the following elements: neodymium, praseodymium, dysprosium, terbium, europium, samarium, yttrium, terbium, lanthanum, cerium, yttrium, and neodymium, or one or more of their oxides or carbides. The content of rare earth additives in the polycrystalline diamond layer is 0.1-5.0 wt%.

[0009] A further technical solution is that the average particle size of the rare earth additive is ≤50 micrometers, preferably ≤5 micrometers; the content of the rare earth additive in the polycrystalline diamond layer is 0.5-3.0 wt%.

[0010] A further technical solution is that the rare earth additive is selected from one or more of cerium oxide, yttrium oxide, lanthanum oxide, neodymium oxide, praseodymium oxide, and samarium oxide; and the binder is selected from one or more of cobalt, nickel, iron, or their alloys.

[0011] A further technical solution is that the rare earth additive is a mixture of oxides or carbides of two or more rare earth elements.

[0012] A further technical solution is that the binder is selected from one or more of cobalt, nickel, iron, or their alloys.

[0013] The second technical solution adopted in this invention is:

[0014] A method for preparing a high-performance polycrystalline diamond composite sheet as described in the first technical solution includes the following steps: Step S1, diamond micropowder and rare earth additives are first mixed by dry mixing or wet mixing, so that the rare earth additives are uniformly attached to the surface of the diamond micropowder; Step S2, a binder is added to the mixture obtained in Step S1, and a second mixing is carried out, followed by drying and / or sieving to obtain a composite powder; Step S3, the composite powder is loaded into a high-temperature resistant metal liner and placed into a cemented carbide matrix to assemble a sintered blank; Step S4, the sintered blank is sintered under ultra-high pressure of 5.5-7.5 GPa and high temperature of 1350-1600°C; Step S5, the sintered product is post-treated to obtain a polycrystalline diamond composite sheet.

[0015] A further technical solution is that, in step S1, the dry mixing method uses a three-dimensional mixer or a V-type mixer, and the mixing time is 0.5-4 hours; the wet mixing method includes ultrasonic dispersion in an organic solvent for 0.1-1 hours, followed by ball milling for 0.5-8 hours.

[0016] A further technical solution is to use a high-temperature resistant metal liner made of niobium, molybdenum, zirconium, or rhenium.

[0017] A further technical solution is that, in step S3, the high-temperature resistant metal liner is made of niobium, molybdenum, zirconium or rhenium; and in step S4, the sintering holding time is 2-60 minutes.

[0018] A further technical solution is that, in step S3, a sintered blank is assembled using assembly equipment. The assembly equipment includes a base, with a platform rotatably mounted on the upper side of the base. Four clamps for holding a high-temperature resistant metal liner are evenly distributed near the edge of the upper side of the platform. Around the platform, corresponding to the four clamps, a powder feeding section, a compaction section, a base mounting section, and upper and lower liner sections are sequentially arranged. The upper and lower liner sections include a first column, with a first rotating platform driven by a first servo motor rotatably mounted on the upper end of the first column. A first feeding conveyor belt and a discharging conveyor belt are arranged around the first column. A first electric telescopic rod is vertically arranged downwards on the lower side of the first rotating platform. The first electric telescopic rod has a second electric gripper at its telescopic end; the powder feeding part includes a material tank, a first screw feeder is installed at the lower end of the material tank, the discharge end of the first screw feeder is located above the base; the compaction part includes a mounting rail, a second electric telescopic rod is installed downward on the lower side of the mounting rail, a compaction block is provided on the output shaft of the second electric telescopic rod; the base mounting part includes a second column, a second rotating table driven by a second servo motor is rotatably installed at the upper end of the second column, a second feeding conveyor belt is arranged around the second column, a third electric telescopic rod is vertically arranged downward on the lower side of the second rotating table, and an electric suction cup is installed at the telescopic end of the third electric telescopic rod.

[0019] A further technical solution is that the fixture includes a fixed block, a movable block, and a fourth electric telescopic rod arranged sequentially along the radial direction from the edge to the center of the base. The fixed block and the movable block each have a first arc-shaped groove and a second arc-shaped groove on opposite sides. The first arc-shaped groove has a recessed wall with multiple first rotating grooves. A first driven roller is rotatably mounted within the first rotating groove along a vertical axis, with a portion of the first driven roller protruding from the groove wall of the first arc-shaped groove. The second arc-shaped groove has a recessed wall with one second rotating groove and multiple third rotating grooves. A second driven roller is rotatably mounted within the third rotating groove along a vertical axis. The moving roller and the second rotating groove are equipped with a driving roller along the vertical rotation axis. The end of the driving roller is equipped with a first gear. The second rotating groove is equipped with a first drive motor. The output shaft of the first drive motor is equipped with a second gear. The second gear is connected to the first gear through a transmission gear. Both the second driven roller and the driving roller partially protrude from the groove wall of the second arc-shaped groove. The upper side of the base is equipped with a first guide rail along the radial direction. The lower side of the movable block is slidably connected to the first guide rail through the guide rail groove. The fourth electric telescopic rod is fixed to the upper side of the base through a fixed seat. The telescopic end of the fourth electric telescopic rod is connected to the movable block.

[0020] A first lead screw is provided along the length of the mounting rail. A second drive motor and a rotating seat are respectively located at both ends of the first lead screw. A first drive slider and a second drive slider are threadedly connected to the first lead screw. A first connecting seat is located at the upper end of the second electric telescopic rod, which is fixedly connected to the first drive slider and slidably connected to the mounting rail. A first pressure column is connected to the lower end of the second electric telescopic rod. A first pressure hole is located at the lower end of the first pressure column, and a first pressure sensor is located at the bottom of the first pressure hole. A second pressure column slides vertically within the first pressure hole, and the upper end of the second pressure column is connected to the first pressure sensor via a first spring. The lower end of the column is connected to the upper end of the compacted block. The outer wall of the upper end of the compacted block is provided with a first annular plate. The outer wall of the lower end of the compacted block is provided with a sleeve that slides up and down. The outer wall of the sleeve is provided with a second annular plate. The first annular plate and the second annular plate are connected by a second spring. At least two distance sensors aligned with the second annular plate are provided on the first annular plate. A second connecting seat is provided on the lower side of the second drive slider. The second connecting seat is slidably connected to the mounting rail. A fifth electric telescopic rod is provided on the lower side of the second connecting seat. A miniature screw feeder is vertically installed at the telescopic end of the fifth electric telescopic rod. The mounting rail is installed on one side of the machine through a support frame. A material box is provided on the side of the support frame.

[0021] A third column is installed between the second column and the second feeding conveyor belt. A third rotating table driven by a third servo motor is rotatably installed at the upper end of the third column. First electric grippers are installed on opposite sides of the third rotating table. The first electric grippers include a first left gripper and a first right gripper arranged symmetrically. A first driving cavity is horizontally installed on the third rotating table at the position corresponding to the first left gripper and the first right gripper. A first driving bar hole connected to the first driving cavity is provided on the side of the third rotating table. A second guide rail is horizontally installed in the first driving bar hole of the third rotating table. The first left gripper and the first right gripper are both horizontally slidably connected to the second guide rail. A second lead screw is horizontally installed in the first driving cavity. A first driving gear is coaxially sleeved in the middle of the second lead screw. The first driving gear is driven by the third driving motor. The threads of the second lead screw on both sides of the first driving gear rotate in opposite directions. A first left driving block and a first right driving block are threadedly matched to the left and right sides of the first driving gear. The first left driving block is connected to the first left gripper, and the first right driving block is connected to the first right gripper.

[0022] Compared with existing technologies, the beneficial effects of this invention are: 1. Strong interface activation and bridging effect: Rare earth elements (such as Ce, Y, La) have extremely high chemical activity under ultra-high pressure and high temperature, and can react with carbon atoms on the diamond surface to generate stable rare earth carbides (such as CeC2, LaC2) in situ. These carbide phases form strong "chemical bridges" between diamond particles and between diamond and binder (cobalt), transforming the traditional weak physical bonding into strong chemical bonding, greatly enhancing the interfacial bonding strength. This is the fundamental reason for improving the impact toughness and overall strength of PDC; 2. Deep purification and interface optimization effect: Rare earth oxides (such as CeO2, Y2O3) have excellent oxygen storage and release capabilities, and can actively capture and fix oxygen, moisture and other impurity gases on the surface of diamond micropowder and in the sintering cavity during the sintering process. This effectively purifies the surface of diamond particles, eliminating obstacles that hinder the formation of direct covalent bonds between diamonds, thereby promoting the formation of a denser and more uniform DD bond network; 3. Significantly improves wear resistance and thermal stability: Due to the enhanced interfacial chemical bonding and the densification of the microstructure, the PDC of this invention exhibits extremely high hardness and wear resistance. Experiments show that, under the same process and testing conditions, the wear resistance (characterized by the wear ratio) of the PDC of this invention is at least 10% higher than that of traditional PDC without rare earth elements, and some preferred formulations can improve it by 20%-35%. At the same time, the stable thermal barrier formed by rare earth additives (especially yttrium oxide, cerium oxide, etc.) at the grain boundaries can effectively block the migration of cobalt at high temperatures and inhibit the graphitization catalysis of diamond by cobalt. The PDC of this invention exhibits excellent thermal stability, and its heat resistance temperature (defined as the upper limit temperature at which hardness does not significantly decline) is significantly increased from about 900°C of traditional high-end products to above 1030°C, with some samples reaching 1050°C. This results in a longer service life for the product under extreme conditions such as deep drilling and high-speed dry cutting; 4. Highly efficient assisted sintering and densification effect: The addition of rare earth elements lowers the activation energy of the overall sintering system, promoting material diffusion and flow. This allows for a more complete and rapid densification process of the diamond layer under the same or slightly lower temperature and pressure conditions, helping to eliminate internal porosity and obtain a nearly fully dense microstructure, thereby optimizing the overall mechanical properties. Attached Figure Description

[0023] Figure 1 The image shows a scanning electron microscope (SEM) image of the cross-section of the PDC diamond layer prepared in an embodiment of the present invention, revealing a dense and uniform structure with visible distribution of rare earth phases at the interface.

[0024] Figure 2 This is the energy spectrum of the PDC diamond layer cross section prepared in an embodiment of the present invention.

[0025] Figure 3This is a comparison chart showing the wear ratio of traditional PDC composite sheets (without rare earth) and PDCs (with rare earth) in the embodiments of the present invention.

[0026] Figure 4 This is a comparison diagram of the thermal stability of traditional PDC composite sheets (without rare earth elements) and PDCs (with rare earth elements) in the embodiments of the present invention.

[0027] Figure 5 This is a schematic diagram of the assembly equipment of the present invention.

[0028] Figure 6 This is a top view of the base of the assembly equipment of the present invention.

[0029] Figure 7 This is a schematic cross-sectional view of the fixture in the assembly equipment of the present invention.

[0030] Figure 8 for Figure 5 A magnified view of the area marked A in the middle.

[0031] Figure 9 for Figure 5 A magnified view of the area marked B.

[0032] Figure 10 This is a schematic diagram of the first electric gripper of the assembly equipment of the present invention.

[0033] Figure 11 This is a schematic diagram of the upper and lower parts of the lining of the present invention.

[0034] Figure 12 This is a schematic diagram of the second electric gripper of the assembly equipment of the present invention.

[0035] Figure 13 This is a miniature screw feeder for the assembly equipment of the present invention.

[0036] Icons: 1-Base, 2-Platform, 3-Clamping device, 4-Powder feeding section, 5-Compacting section, 6-Base mounting section, 7-Upper and lower lining sections, 8-First column, 9-First rotating table, 10-First feeding conveyor belt, 11-Unloading conveyor belt, 12-First electric telescopic rod, 13-Second electric gripper, 14-Material tank, 15-First screw feeder, 16-Mounting rail, 17-Second electric telescopic rod, 18-Compacted block, 19-Second column, 20-Second rotating table, 21-Second feeding conveyor belt, 22-Third electric telescopic rod 23-Electric suction cup, 24-Second left claw, 25-Second right claw, 26-Second drive cavity, 27-Second drive bar hole, 28-Third guide rail, 29-Third lead screw, 30-Second drive gear, 31-Fourth drive motor, 32-Second left drive block, 33-Second right drive block, 34-Fixed block, 35-Moving block, 36-Fourth electric telescopic rod, 37-First arc-shaped groove, 38-Second arc-shaped groove, 39-First rotating groove, 40-First driven roller, 41-Second rotating groove, 42-Third rotating groove, 43 44-Second driven roller, 45-Driven roller, 46-First gear, 47-First drive motor, 48-Second gear, 49-Transmission gear, 50-Fixed seat, 51-Second drive motor, 52-First connecting seat, 53-First pressure column, 54-First pressure hole, 55-Second pressure column, 56-First spring, 57-First annular plate, 58-Sleeve, 59-Second annular plate, 60-Second spring, 61-Distance sensor, 62-Second connecting seat, 63-Fifth electric telescopic rod, 64- Miniature screw feeder, 65-support frame, 66-material box, 67-third column, 68-third rotating table, 69-first left claw, 70-first right claw, 71-first drive cavity, 72-first drive bar hole, 73-second guide rail, 74-second lead screw, 75-first drive gear, 76-third drive motor, 77-first left drive block, 78-first right drive block, 79-third pressure column, 80-second pressure hole, 81-second pressure sensor, 82-fourth pressure column, 83-third spring, 84-first guide rail. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] Example 1:

[0039] A method for preparing high-performance polycrystalline diamond composite sheets includes the following steps: Step S1, diamond micropowder and rare earth additives are first mixed by dry mixing or wet mixing to make the rare earth additives uniformly adhere to the surface of the diamond micropowder; Step S2, a binder is added to the mixture obtained in Step S1, and a second mixing is carried out, followed by drying and / or sieving to obtain a composite powder; Step S3, the composite powder is loaded into a high-temperature resistant metal liner and placed into a cemented carbide matrix to assemble a sintered green body; Step S4, the sintered green body is sintered under ultra-high pressure of 5.5-7.5 GPa and high temperature of 1350-1600°C; Step S5, the sintered product is post-treated to obtain a polycrystalline diamond composite sheet.

[0040] Example 2 (using a niobium cup, wet ball milling for mixing)

[0041] Raw materials: 98wt% diamond micro powder with an average particle size of 15μm, 1wt% cobalt powder (1-2μm), and 1.0wt% cerium oxide nanoparticles and yttrium oxide with an average particle size of 80nm.

[0042] Preparation details:

[0043] Mixing: Place diamond micro powder and nano-cerium oxide in a ball mill jar, add anhydrous ethanol (liquid-to-solid volume ratio approximately 3:1) and cemented carbide grinding balls (ball-to-material ratio 5:1). Ball mill at 350 rpm for 6 hours on a planetary ball mill.

[0044] Adding binder and drying: Add cobalt powder to the container and continue ball milling for 2 hours. Transfer the slurry to a vacuum drying oven and dry at 80°C for 12 hours. After drying, the lumps are gently crushed and passed through a 200-mesh sieve to obtain composite powder.

[0045] Assembly: Take a certain amount of composite powder, fill it into a metal cup made of pure niobium, spread it evenly, and then place it into a WC-13%Co cemented carbide matrix.

[0046] Sintering: The assembly is placed in a six-sided press and sintered at 6.5 GPa and 1450°C for 10 minutes.

[0047] Post-processing: PDC sample A1 was obtained by wire cutting, double-end grinding and polishing.

[0048] Example 3 (Dry three-dimensional mixing using a niobium cup)

[0049] Raw materials: 98wt% diamond micro powder with a particle size of 12μm, 1wt% cobalt binder, 0.7wt% yttrium oxide nanoparticles with an average particle size of 50nm, and 0.3wt% lanthanum oxide nanoparticles with an average particle size of 100nm.

[0050] Preparation details:

[0051] Premixing (dry mixing): Diamond micro powder, nano-yttrium oxide and nano-lanthanum oxide are placed together in a three-dimensional motion mixer and continuously mixed at 90 rpm for 45 minutes.

[0052] General mixing: Add the premixed powder and cobalt powder to the same mixer and continue mixing for 1 hour.

[0053] Sieving and Assembly: The mixed powder was directly sieved through a 100-mesh sieve. The powder was then placed into a niobium metal cup, and the subsequent assembly steps were the same as in Example 1.

[0054] Sintering: The sintering parameters were 6.5 GPa, 1520°C, and pressure holding for 10 minutes. PDC sample A2 was obtained.

[0055] Example 4 (Using a niobium cup, ultrasonic-assisted vibration mixing)

[0056] Raw materials: 97wt% mixed diamond micro powder with an average particle size of 17μm, 2wt% cobalt powder, and 1wt% cerium-rich mixed rare earth oxides (CeO2>50%, La2O3~30%, average particle size 150nm).

[0057] Preparation details:

[0058] Ultrasonic dispersion: Diamond micro powder and rare earth oxides are first subjected to strong ultrasonic dispersion for 30 minutes.

[0059] Overall mixing: Add a small amount of cobalt powder as a process control agent to the above dispersion system and continue ultrasonic vibration mixing for 30 minutes.

[0060] Sieving and Assembly: The mixed powder was directly sieved through a 100-mesh sieve. The powder was then placed into a niobium metal cup, and the subsequent assembly steps were the same as in Example 1.

[0061] Assembly and sintering: The powder was loaded into a niobium metal cup. The sintering conditions were 5.8 GPa, 1420°C, and pressure holding for 10 minutes. PDC sample A3 was obtained.

[0062] Comparative example (no rare earth added, traditional process)

[0063] The raw materials and preparation process were kept as similar as possible to those in Example 1, but no rare earth oxides were added. The diamond powder content was adjusted to 98 wt%, and the cobalt powder content was 1 wt%. Mixing was performed using a conventional three-dimensional mixing method at 90 rpm for 1 hour. Comparative sample D1 was prepared as in Example 1.

[0064] Performance Testing and Comparative Analysis: The following standard tests were performed on the above samples A1, A2, A3 and comparative example D1:

[0065] Wear ratio test: A VTL vertical lathe was used, with natural granite as the test material, a diameter of 1.2m, a cutting depth of 0.5mm, and a feed rate of 1.5mm / revolution.

[0066] Heat resistance temperature test: The sample is heated at the same rate (5°C / min) in a non-inert atmosphere until the diamond layer is completely delaminated. The temperature point at which the coefficient of thermal expansion changes abruptly is defined as the heat resistance temperature of the sample.

[0067] Results analysis:

[0068] Figure 3 This is a comparison of the grinding volume of the implemented case with that of traditional PDC composite sheets. Figure 4 This is a comparison of the thermal expansion of an implemented case study with that of a traditional PDC composite sheet. The results illustrate:

[0069] Process compatibility and performance consistency: Examples 1-3 demonstrate the successful application of various mixing processes, including wet long-time ball milling, dry three-dimensional mixing, and ultrasonic-assisted short-time ball milling, proving that the technology of this invention has broad compatibility and flexibility with existing PDC production equipment and processes. Regardless of the specific implementation method, the samples with added rare earth elements (A1-A3) showed significant and consistent leaps in wear resistance (increased by 19.2%-32.8%) and thermal stability temperature (increased by 65-130°C) compared to the comparative example D1, fully meeting and exceeding the expected targets (wear resistance >10%, heat resistance temperature >1030°C).

[0070] Synergistic effect: Example 2 (A2) achieved the best overall performance by using two rare earth oxides and a dry mixing process, which suggests the synergistic effect between rare earth elements and the potential for optimizing the mixing process.

[0071] The above data fully demonstrates that by adding trace amounts (0.1-5.0 wt%) of rare earth elements or their oxides / carbides to diamond composite sheets, a leapfrog improvement in wear resistance and thermal stability can be achieved synergistically. The technical effect is significant, with outstanding substantial characteristics and progress.

[0072] Example 5:

[0073] In step S3, a sintered blank is assembled using assembly equipment. The assembly equipment includes a base 1, a platform 2 rotatably mounted on the upper side of the base 1, and four clamps 3 evenly distributed near the edge of the upper side of the platform 2 for holding a high-temperature resistant metal liner. Around the platform 2, corresponding to the four clamps 3, a powder feeding section 4, a compaction section 5, a substrate mounting section 6, and upper and lower liner sections 7 are sequentially arranged. The upper and lower liner sections 7 include a first column 8, a first rotating table 9 driven by a first servo motor rotatably mounted on the upper end of the first column 8, a first feeding conveyor belt 10 and a discharging conveyor belt 11 arranged around the first column 8, and a first electric telescopic rod 12 vertically downwards on the lower side of the first rotating table 9. The telescopic end of the first electric telescopic rod 12 is... The system includes a second electric gripper 13; the powder feeding part 4 includes a material tank 14, a first screw feeder 15 is installed at the lower end of the material tank 14, the discharge end of the first screw feeder 15 is located above the base 2; the compaction part 5 includes a mounting rail 16, a second electric telescopic rod 17 is installed downward on the lower side of the mounting rail 16, a compaction block 18 is provided on the output shaft of the second electric telescopic rod 17; the base mounting part 6 includes a second column 19, a second rotating table 20 driven by a second servo motor is rotatably installed at the upper end of the second column 19, a second feeding conveyor belt 21 is arranged around the second column 19, a third electric telescopic rod 22 is vertically arranged downward on the lower side of the second rotating table 20, and an electric suction cup 23 is installed at the telescopic end of the third electric telescopic rod 22. This application utilizes assembly equipment to automate and rapidly complete step S3, which involves loading composite powder into a high-temperature resistant metal liner, placing a hard alloy substrate inside, and assembling it into a sintered blank. It also allows for precise control of the amount of composite powder loaded each time, thereby controlling the final product's dimensions and avoiding significant errors. Specifically, the prepared hard alloy substrate liner is placed onto the base 2 via the upper and lower parts 7 and secured with clamps 3. After securing, the base 2 is rotated by the base 1, which houses a first servo motor to control this rotation. By rotating the clamps 3 (with the liner secured) to the powder feeding section 4, the composite powder from the material tank 14 is fed into the liner via a first screw feeder 15. The amount fed is precisely controlled by adjusting the rotation angle of the first screw feeder 15, thus controlling the thickness of the polycrystalline diamond layer. After the powder is dispensed, the base 2 rotates to move the liner to the compaction section 5. The compaction section 5 uses the second electric telescopic rod 17 to drive the compaction block 18 downwards to compact and level the composite powder in the liner. After leveling, the base 2 rotates to the position of the substrate mounting section 6. The second rotating table 20 drives the third electric telescopic rod 22 and the electric suction cup 23 to pick up the hard alloy substrate from the second feeding conveyor belt 21. Then, the second rotating table 20 places the electric suction cup 23 with the hard alloy substrate on top of the liner. Finally, the third electric telescopic rod 22 is extended to place the hard alloy substrate into the liner.After placement, the assembled sintered billet is rotated to the upper and lower parts 7 of the inner liner by rotating the base 2. The assembled sintered billet is then removed, and a new inner liner is installed on the base 2. Figure 1 The upper and lower parts 7 of the inner lining are not shown in the image to avoid obscuring the compacted part 5. Figure 11 The upper and lower parts 7 of the inner lining are shown separately in the diagram.

[0074] The clamp 3 includes a fixed block 34, a movable block 35, and a fourth electric telescopic rod 36 arranged sequentially from the edge to the center along the radial direction of the base 2. The fixed block 34 and the movable block 35 have a first arc-shaped groove 37 and a second arc-shaped groove 38 on opposite sides, respectively. The groove wall of the first arc-shaped groove 37 has a plurality of first rotating grooves 39 recessed within it. A first driven roller 40 is rotatably mounted within the first rotating groove 39 along a vertical axis, with the first driven roller 40 partially protruding from the groove wall of the first arc-shaped groove 37. The groove wall of the second arc-shaped groove 38 has a second rotating groove 41 recessed within it and a plurality of third rotating grooves 42. A second driven roller 43 is rotatably mounted within the third rotating groove 42 along a vertical axis. An active roller 44 is provided along the vertical rotation axis inside 41. A first gear 45 is installed at the end of the active roller 44. A first drive motor 46 is provided in the second rotation groove 41. A second gear 47 is installed on the output shaft of the first drive motor 46. The second gear 47 is connected to the first gear 45 through a transmission gear 48. Both the second driven roller 43 and the active roller 44 protrude partially from the groove wall of the second arc-shaped groove 38. A first guide rail 84 is provided radially on the upper side of the base 2. The lower side of the movable block 35 is slidably connected to the first guide rail 84 through the guide rail groove. A fourth electric telescopic rod 36 is fixed to the upper side of the base 2 through a fixed seat 49. The telescopic end of the fourth electric telescopic rod 36 is connected to the movable block 35. By cooperating with the fourth electric telescopic rod 36 and the first guide rail 84, the movement of the movable block 35 can be controlled to separate and bring the movable block 35 and the fixed block 34 together, thereby achieving the fixing and removal of the liner. When installing the liner, a certain distance is separated to facilitate the insertion of the liner, and then the fixed block 34 and the movable block 35 are brought together to clamp the liner, thus achieving the fixing and positioning of the liner. Furthermore, during the subsequent compaction and placement of the hard alloy substrate, the first drive motor 46 drives the liner to rotate within the first arc-shaped groove 37 and the second arc-shaped groove 38. In this way, during the compaction and placement of the hard alloy substrate, the rotation of the liner facilitates the leveling and compaction of the composite powder inside the liner, and when placing the hard alloy substrate, the rotation ensures more thorough contact of the bonding surfaces.

[0075] The mounting rail 16 is provided with a first lead screw along its length. A second drive motor 50 and a rotating seat are respectively provided at both ends of the first lead screw. A first drive slider and a second drive slider are threadedly connected to the first lead screw. A first connecting seat 51 is provided at the upper end of the second electric telescopic rod 17. The first connecting seat 51 is fixedly connected to the first drive slider and slidably connected to the mounting rail 16. A first pressure column 52 is connected to the lower end of the second electric telescopic rod 17. A first pressure hole 53 is provided at the lower end of the first pressure column 52. A first pressure sensor 54 is provided at the bottom of the first pressure hole 53. A second pressure column 55 is slidably arranged inside the first pressure hole 53. The upper end of the second pressure column 55 is connected to the first pressure sensor 54 via a first spring 56, and the lower end of the second pressure column 55 is connected to the compaction point. The upper end of the compacted block 18 is connected to the outer wall of the upper end of the compacted block 18, and a first annular plate 57 is provided on the outer wall of the lower end of the compacted block 18. A sleeve 58 is slidably provided on the outer wall of the lower end of the compacted block 18. A second annular plate 59 is provided on the outer wall of the sleeve 58. The first annular plate 57 and the second annular plate 59 are connected by a second spring 60. At least two distance sensors 61 aligned with the second annular plate 59 are provided on the first annular plate 57. A second connecting seat 62 is provided on the lower side of the second drive slider. The second connecting seat 62 is slidably connected to the mounting rail 16. A fifth electric telescopic rod 63 is provided on the lower side of the second connecting seat 62. A miniature screw feeder 64 is vertically installed at the telescopic end of the fifth electric telescopic rod 63. The mounting rail 16 is installed on one side of the base 2 through a support frame 65. A material box 66 is provided on the side of the support frame 65. During compaction, the second drive motor 50 drives the second electric telescopic rod 17 to move and align with the liner containing the composite powder. The rod then extends, causing the compaction block 18 to enter the liner. During entry, the second annular plate 59 rests against the opening at the top of the liner, and the first annular plate 57 moves towards the second annular plate 59. Simultaneously, the first drive motor 46 drives the liner to rotate. During rotation, the compaction block 18 gradually compacts and flattens. During this process, the first pressure sensor 54 determines the pressure applied to the compaction block 18. Under appropriate pressure, the composite powder is compacted, and the distance between the first annular plate 57 and the second annular plate 59 gradually stabilizes. The distance sensor 61 then determines the thickness of the composite powder within the liner. If the final compacted thickness differs from the designed thickness, and the error exceeds the allowable range, adjustments are needed to bring the thickness within the designed range. Specifically, when the thickness is greater than the design range, the second drive motor 50 is controlled to drive the fifth electric telescopic rod 63 to move above the liner and extend it, so that the lower end of the micro screw feeder 64 contacts the composite powder in the liner and extracts a portion of the composite powder. The specific extraction amount is determined by controlling the rotation angle of the internal screw shaft of the fourth servo motor on the micro screw feeder 64 according to the thickness value exceeded.After extraction, the composite powder in the liner is re-spread and compacted using the compaction block 18, and the thickness is checked. Once the thickness is within acceptable limits, it is rotated to the substrate mounting section 6 for substrate installation. Alternatively, if the thickness of the composite powder is lower than the design value after the first compaction, a suitable amount of composite powder can be taken from the material box 66 using the micro-screw feeder 64 and placed into the liner for re-compaction and spreading. This structure allows for better control of the thickness of the composite powder in the liner, thereby controlling the final product's pass rate and quality. The micro-screw feeder 64 includes a fourth servo motor at the top and a material tube. A rotating shaft and spiral blades surrounding the rotating shaft are installed inside the material tube. The fourth servo motor drives the rotating shaft to rotate, thereby controlling the spiral blades to guide the composite powder into or out of the material tube.

[0076] A third column 67 is disposed between the second column 19 and the second feeding conveyor belt 21. A third rotating table 68, driven by a third servo motor, is rotatably mounted on the upper end of the third column 67. First electric grippers are disposed on opposite sides of the third rotating table 68. Each first electric gripper includes a first left gripper 69 and a first right gripper 70 symmetrically arranged. A first driving cavity 71 is horizontally disposed on the third rotating table 68 at positions corresponding to the first left gripper 69 and the first right gripper 70. A first driving bar hole 72, communicating with the first driving cavity 71, is disposed on the side of the third rotating table 68. A third driving bar hole 72 is horizontally disposed within the first driving bar hole 72 of the third rotating table 68. The second guide rail 73, the first left claw 69 and the first right claw 70 are all horizontally slidably connected to the second guide rail 73. The first drive cavity 71 is horizontally provided with a second lead screw 74. The middle part of the second lead screw 74 is coaxially sleeved with a first drive gear 75. The first drive gear 75 is driven by a third drive motor 76. The threads of the second lead screw 74 on both sides of the first drive gear 75 rotate in opposite directions. The second lead screw 74 is threadedly matched with a first left drive block 77 and a first right drive block 78 on the left and right sides of the first drive gear 75. The first left drive block 77 is connected to the first left claw 69, and the first right drive block 78 is connected to the first right claw 70. During the installation of the cemented carbide substrate, the substrate is transported via the second feeding conveyor belt 21 to the space between the first left claw 69 and the first right claw 70, which are positioned on the second feeding conveyor belt 21. Then, the third drive motor 76, in conjunction with the second lead screw 74, drives the first left claw 69 and the first right claw 70 to move closer together and clamp the cemented carbide substrate. Next, the third rotating table 68 rotates the cemented carbide substrate to the other side, and the third electric telescopic rod 22 extends to bring the electric suction cup 23 into contact with the cemented carbide substrate, allowing the electric suction cup 23 to adhere to the cemented carbide substrate. Then, the first left claw 69 and the first right claw 70 separate and release the cemented carbide substrate, and the second rotating table 20 moves the cemented carbide substrate to be positioned above the inner liner. With the cooperation of the first left claw 69 and the first right claw 70, the hard alloy substrate can be picked up from the second feeding conveyor belt 21 and positioned simultaneously. This ensures accurate positioning of the suction point when fixed by the electric suction cup 23, allowing for accurate placement into the liner. The lower end of the third electric telescopic rod 22 is connected to a third pressure column 79. A second pressure hole 80 is located at the lower end of the third pressure column 79. A second pressure sensor 81 is located at the bottom of the second pressure hole 80. A fourth pressure column 82 slides vertically within the second pressure hole 80. The upper end of the fourth pressure column 82 is connected to the second pressure sensor 81 via a third spring 83, and the lower end of the fourth pressure column 82 is connected to the electric suction cup 23. Figure 11As shown, the structure of the second electric gripper 13 is the same as that of the first electric gripper. The second electric gripper 13 includes a gripper block and a second left gripper 24 and a second right gripper 25 arranged symmetrically on the left and right sides. The gripper block has a second drive cavity 26 horizontally arranged at the position corresponding to the second left gripper 24 and the second right gripper 25. The side of the gripper block has a second drive bar hole 27 communicating with the second drive cavity 26. A third guide rail 28 is horizontally arranged in the second drive bar hole 27 of the gripper block. The first left gripper 69 and the first right gripper 70 slide horizontally with the third guide rail 28. The third lead screw 29 is horizontally arranged in the second drive cavity 26. The second drive gear 30 is coaxially sleeved in the middle of the third lead screw 29. The second drive gear 30 is driven by the fourth drive motor 31. The threads of the third lead screw 29 on both sides of the second drive gear 30 rotate in opposite directions. The third lead screw 29 is threadedly matched with the second left drive block 32 and the second right drive block 33 on the left and right sides of the second drive gear 30. The second left drive block 32 is connected to the second left claw 24, and the second right drive block 33 is connected to the second right claw 25.

[0077] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A rare-earth-doped high-performance polycrystalline diamond composite sheet, comprising a cemented carbide matrix and a polycrystalline diamond layer sintered thereon, characterized in that... The polycrystalline diamond layer comprises diamond micron powder, binder and rare earth additives. The rare earth additives are one or more of the following elements: neodymium, praseodymium, dysprosium, terbium, europium, samarium, yttrium, terbium, lanthanum, cerium, yttrium and neodymium, or one or more of their oxides or carbides. The content of the rare earth additives in the polycrystalline diamond layer is 0.1-5.0 wt%.

2. The rare-earth-doped high-performance polycrystalline diamond composite sheet according to claim 1, characterized in that: The average particle size of the rare earth additive is ≤50 micrometers; the content of the rare earth additive in the polycrystalline diamond layer is 0.5-3.0 wt%.

3. The rare-earth-doped high-performance polycrystalline diamond composite sheet according to claim 1, characterized in that: The rare earth additive is selected from one or more of cerium oxide, yttrium oxide, lanthanum oxide, neodymium oxide, praseodymium oxide, and samarium oxide; the binder is selected from one or more of cobalt, nickel, iron, or their alloys.

4. A method for preparing a high-performance polycrystalline diamond composite sheet as described in any one of claims 1-3, characterized in that, The process includes the following steps: Step S1, mixing diamond micron powder and the rare earth additive using a dry or wet mixing method to ensure the rare earth additive is uniformly adhered to the surface of the diamond micron powder; Step S2, adding a binder to the mixture obtained in Step S1 and mixing again, followed by drying and / or sieving to obtain a composite powder; Step S3, loading the composite powder into a high-temperature resistant metal liner and placing it into a hard alloy matrix to assemble a sintered blank; Step S4, sintering the sintered blank under ultra-high pressure of 5.5-7.5 GPa and high temperature of 1350-1600°C; Step S5, post-processing the sintered product to obtain the polycrystalline diamond composite sheet.

5. The method for preparing high-performance polycrystalline diamond composite sheets according to claim 4, characterized in that: In step S1, the dry mixing method uses a three-dimensional mixer or a V-type mixer, and the mixing time is 0.5-4 hours; the wet mixing method includes ultrasonic dispersion in an organic solvent for 0.1-1 hours, followed by ball milling for 0.5-8 hours.

6. The method for preparing high-performance polycrystalline diamond composite sheets according to claim 4, characterized in that: In step S3, the high-temperature resistant metal liner is made of niobium, molybdenum, zirconium or rhenium; in step S4, the sintering holding time is 2-60 minutes.

7. The method for preparing high-performance polycrystalline diamond composite sheets according to claim 4, characterized in that: In step S3, a sintered blank is assembled using an assembly device. The assembly device includes a base (1), a platform (2) is rotatably mounted on the upper side of the base (1), and four clamps (3) for holding a high-temperature resistant metal liner are evenly distributed near the edge of the upper side of the platform (2). A powder feeding part (4), a compaction part (5), a base installation part (6), and an upper and lower part (7) of the liner are arranged sequentially around the four clamps (3) of the platform (2). The upper and lower part (7) of the liner includes a first column (8), a first rotating table (9) driven by a first servo motor is rotatably mounted on the upper end of the first column (8), a first feeding conveyor belt (10) and a unloading conveyor belt (11) are arranged around the first column (8), and a first electric telescopic rod (12) is vertically mounted on the lower side of the first rotating table (9). A second electric telescopic rod (12) is mounted on the telescopic end of the first electric telescopic rod (12). The gripper (13); the powder feeding part (4) includes a material tank (14), the lower end of the material tank (14) is equipped with a first screw feeder (15), the discharge end of the first screw feeder (15) is placed above the base (2), the compaction part (5) includes a mounting rail (16), the lower side of the mounting rail (16) is equipped with a second electric telescopic rod (17), the output shaft of the second electric telescopic rod (17) is provided with a compaction block (18), the base mounting part (6) includes a second column (19), the upper end of the second column (19) is rotatably equipped with a second rotating table (20) driven by a second servo motor, the second column (19) is surrounded by a second feeding conveyor belt (21), the lower side of the second rotating table (20) is vertically downward equipped with a third electric telescopic rod (22), the telescopic end of the third electric telescopic rod (22) is equipped with an electric suction cup (23).

8. The method for preparing high-performance polycrystalline diamond composite sheets according to claim 7, characterized in that: The clamp (3) includes a fixed block (34), a movable block (35), and a fourth electric telescopic rod (36) arranged sequentially from the edge to the center along the radial direction of the base (2). The fixed block (34) and the movable block (35) are respectively provided with a first arc-shaped groove (37) and a second arc-shaped groove (38) on opposite sides. The groove wall of the first arc-shaped groove (37) is recessed and provided with a plurality of first rotating grooves (39). A first driven roller (40) is rotatably arranged in the first rotating groove (39) along the vertical axis. The first driven roller (40) partially protrudes from the groove wall of the first arc-shaped groove (37). The groove wall of the second arc-shaped groove (38) is recessed and provided with a second rotating groove (41) and a plurality of third rotating grooves (42). A second driven roller (43) is rotatably arranged in the third rotating groove (42) along the vertical axis. The second rotating groove (41) is rotatably arranged in the second rotating groove (42) along the vertical axis. The moving shaft is provided with an active roller (44), and the end of the active roller (44) is equipped with a first gear (45). The second rotating groove (41) is provided with a first drive motor (46), and the output shaft of the first drive motor (46) is equipped with a second gear (47). The second gear (47) is connected to the first gear (45) through a transmission gear (48). The second driven roller (43) and the active roller (44) both partially protrude from the groove wall of the second arc-shaped groove (38). The upper side of the base (2) is provided with a first guide rail (84) along the radial direction. The lower side of the movable block (35) is slidably connected to the first guide rail (84) through the guide rail groove. The fourth electric telescopic rod (36) is fixed to the upper side of the base (2) through a fixed seat (49). The telescopic end of the fourth electric telescopic rod (36) is connected to the movable block (35).

9. The method for preparing high-performance polycrystalline diamond composite sheets according to claim 7, characterized in that: The mounting rail (16) is provided with a first lead screw along its length. A second drive motor (50) and a rotating seat are respectively provided at both ends of the first lead screw. A first drive slider and a second drive slider are threadedly connected to the first lead screw. A first connecting seat (51) is provided at the upper end of the second electric telescopic rod (17). The first connecting seat (51) is fixedly connected to the first drive slider and slidably connected to the mounting rail (16). A first pressure column (52) is connected to the lower end of the second electric telescopic rod (17). A first pressure hole (53) is provided at the lower end of the first pressure column (52). A first pressure sensor (54) is provided at the bottom of the first pressure hole (53). A second pressure column (55) is slidably arranged up and down in the first pressure hole (53). The upper end of the second pressure column (55) is connected to the first pressure sensor (54) through a first spring (56). The lower end of the second pressure column (55) is connected to the compaction block (18). The upper end is connected to the upper end of the compaction block (18), the outer wall of the upper end of the compaction block (18) is provided with a first ring plate (57), the outer wall of the lower end of the compaction block (18) is provided with a sleeve (58) that slides up and down, the outer wall of the sleeve (58) is provided with a second ring plate (59), the first ring plate (57) and the second ring plate (59) are connected by a second spring (60), at least two distance sensors (61) aligned with the second ring plate (59) are provided on the first ring plate (57); the lower side of the second drive slider is provided with a second connecting seat (62), the second connecting seat (62) is slidably connected to the mounting rail (16), the lower side of the second connecting seat (62) is provided with a fifth electric telescopic rod (63), the telescopic end of the fifth electric telescopic rod (63) is vertically installed with a micro screw feeder (64), the mounting rail (16) is installed on one side of the base (2) through a support frame (65), and a material box (66) is provided on the side of the support frame (65).

10. The method for preparing high-performance polycrystalline diamond composite sheets according to claim 7, characterized in that: A third column (67) is provided between the second column (19) and the second feeding conveyor belt (21). A third rotating table (68) driven by a third servo motor is rotatably provided at the upper end of the third column (67). First electric grippers are provided on both sides of the third rotating table (68). The first electric grippers include a first left gripper (69) and a first right gripper (70) symmetrically arranged. A first driving cavity (71) is horizontally provided on the third rotating table (68) at the position corresponding to the first left gripper (69) and the first right gripper (70). A first driving bar hole (72) communicating with the first driving cavity (71) is provided on the side of the third rotating table (68). A second guide rail is horizontally provided in the first driving bar hole (72) of the third rotating table (68). 73), the first left claw (69) and the first right claw (70) are both horizontally slidably connected to the second guide rail (73). The first drive cavity (71) is horizontally provided with a second lead screw (74). The middle part of the second lead screw (74) is coaxially sleeved with a first drive gear (75). The first drive gear (75) is driven by a third drive motor (76). The screws on both sides of the second lead screw (74) rotate in opposite directions. The second lead screw (74) is threadedly matched with a first left drive block (77) and a first right drive block (78) on the left and right sides of the first drive gear (75). The first left drive block (77) is connected to the first left claw (69), and the first right drive block (78) is connected to the first right claw (70).

Images