Polycrystalline diamond compact and preparation method thereof

Abstract

The invention relates to the technical field of polycrystalline diamond, and discloses a polycrystalline diamond compact and a preparation method thereof.The method comprises the steps that a TiMoTa multi-component transition layer composed of carbon-philic elements is sputtered on the surface of diamond micro-powder, so that diamond nucleation is promoted, the crack resistance is improved, and the polycrystalline diamond compact is obtained; the polycrystalline diamond layer and the hard alloy matrix are connected through a pin tenon in a traditional tenon-and-mortise structure, so that the problems that the PDC is poor in abrasion resistance in hard rocks and prone to failure due to excessive abrasive particle abrasion, and the polycrystalline diamond layer and the hard alloy matrix are not firmly connected are solved.

Description

Technical Field

[0001] This invention relates to the field of polycrystalline diamond technology, and more specifically, to a polycrystalline diamond composite sheet and its preparation method. Background Technology

[0002] Polycrystalline diamond composite (PDC) is a widely used superhard material. Its manufacturing process involves sintering diamond micropowder with a cemented carbide matrix under high temperature and pressure. This material combines the high hardness, excellent wear resistance, and outstanding thermal conductivity of diamond with the impact toughness and weldability of cemented carbide, making it a preferred material for drill bit cutting teeth. Currently, PDC drill bits are widely used in geological exploration, oil and gas exploration, and coal drilling.

[0003] Since ancient times, nature has been an inexhaustible source of inspiration for human technology and invention. Many soil cave animals have lived in soil environments for a long time and have evolved body structures and functions adapted to different soil environments. Their body surfaces have excellent wear resistance, drag reduction, and desorption / adhesion reduction functions.

[0004] By observing the surface contours of clam shells, pangolin scales, and comb-scallop shells, geometric features are extracted, thereby using bionics to solve technical problems in the engineering field.

[0005] As the main component of PDC drill bits for rock breaking, PDC composite sheets often face various complex formations, leading to premature failure. Common failure modes of PDC composite sheets include macroscopic fracture, wear, spalling, and faulting. The main reasons are the poor wear resistance and impact resistance of the diamond layer in the PDC composite sheet, and the weak bonding between the diamond layer and the cemented carbide layer. Common non-planar connection improvement methods generally suffer from stress concentration and difficulty in eliminating residual stress.

[0006] Therefore, there is an urgent need to develop new PDC composite sheets to solve stress problems while improving the wear resistance of the diamond layer and the interfacial bonding strength between the diamond layer and the cemented carbide layer. Summary of the Invention

[0007] The purpose of this invention is to provide a polycrystalline diamond composite sheet and its preparation method to solve the above-mentioned problems.

[0008] To achieve the above objectives, the present invention provides the following solution: A method for preparing a polycrystalline diamond composite sheet, comprising: 1) Micron powder cleaning: After acid washing and alkali washing, the diamond micron powder is cleaned with distilled water at high temperature 2-3 times; 2) Transition Layer Preparation: A TiMoTa transition layer was prepared on the surface of diamond micropowder using a DGPSA device. The TiMoTa transition layer comprises a TiMoTa deposition layer and a TiMoTa gradient diffusion layer. The TiMoTa gradient diffusion layer is prepared by exciting Ar... + Argon gas was reverse sputtered to obtain a TiMoTa transition layer containing only the TiMoTa deposited layer. 3) Finished product preparation: The cemented carbide matrix is ​​ultrasonically treated in an anhydrous ethanol environment for 30 minutes. The diamond micro powder from step 2) and the ultrasonically treated cemented carbide matrix are loaded into a metal container and pressed into a sheet to obtain a composite material. The composite material is then assembled into a block along with the metal container and the pyrophyllite assembly block, and sintered in a six-sided press. After sintering, the block is kept at a constant temperature to obtain a sintered body. The metal container is a molybdenum container or a tantalum container. The sintered body is taken out of the six-sided press for cooling and depressurization. After removing the metal container covering the surface, it is ground and polished to obtain a polycrystalline diamond composite sheet. Step 2) specifically includes: Optimized TiMoTa transition layer deposition parameters were selected for the preparation of the TiMoTa diffusion layer. First, the TiMoTa transition layer was prepared in a DGPSA device. After the bipolar power supply was turned on, glow discharge was distributed and covered the TiMoTa target and the surface of diamond micropowder, forming a TiMoTa transition layer consisting of a TiMoTa deposition layer and a TiMoTa gradient diffusion layer. The voltage between the source electrode and the workpiece cathode was reversed for reverse plasma sputtering. The substrate temperature was measured using an infrared thermometer. Under the electric field of the two high-voltage power supplies, the introduced argon gas was excited and ionized into Ar. + Under the drive of a high-voltage electric field, a TiMoTa transition layer containing only a TiMoTa deposition layer was prepared.

[0009] Preferably, in step 1), the acid washing and alkaline washing are performed by boiling the diamond micro powder in 10 wt.% NaOH and 30 wt.% HNO3 solutions for 30 min, respectively.

[0010] Preferably, a deposition time of 30 min and a deposition temperature of 830 °C are selected as the optimized deposition parameters for the TiMoTa transition layer. During reverse sputtering, Ar + The diamond powder was bombarded, which heated it to 800°C and held thereafter.

[0011] Preferably, during the reverse sputtering process, the workpiece voltage is increased from 300-450V to 600-750V, while the source voltage is decreased from 600-750V to 300-450V, and the potential difference between the source electrode and the workpiece cathode is 300V.

[0012] Preferably, the diamond micropowder has a particle size of 20μm-25μm, and the sputtered TiMoTa transition layer has a thickness of 0.1μm-5μm.

[0013] Preferably, in step 3), during sintering, the pressure is first increased to a sintering pressure of 6.2 GPa-7.2 GPa at a pressurization rate of 0.5 GPa / min-1 GPa / min, and the temperature is increased at a rate of 40℃ / s-50℃ / s for sintering. After holding at 1420℃ for 100s-120s, the temperature is increased to a sintering temperature of 1620℃-1780℃ within 40s-50s. After sintering, the temperature is decreased to 680℃ at a rate of 20℃ / s-25℃ / s, held for 6min-9min, and then reduced to room temperature. Finally, the pressure is reduced to atmospheric pressure at a rate of 0.2 GPa / min-0.9 GPa / min.

[0014] Preferably, after sintering in step 3), the temperature is maintained for 240 seconds, then cooled to room temperature at a rate of 30°C / s, and then depressurized to atmospheric pressure at a rate of 1 GPa / min.

[0015] On the other hand, the present invention also provides a polycrystalline diamond composite sheet obtained by the above preparation method, wherein the polycrystalline diamond composite sheet comprises a polycrystalline diamond layer and a cemented carbide matrix; A tenon is set on one side of the polycrystalline diamond layer, and a corresponding sea eye is set on the cemented carbide substrate. The size of the tenon matches that of the sea eye, and the tenon is inserted into the sea eye to form a tenon foot. A composite biomimetic structure is provided on the other side of the polycrystalline diamond layer. The composite biomimetic structure is an alternating convex hull geometric structure and a prism geometric structure.

[0016] Furthermore, the spacing between the convex-shaped geometric structures is 4.0 mm, the major axis of the convex-shaped geometric structures is 3 mm, the minor axis is 2 mm, and the height of the convex-shaped geometric structures is 0.6 mm; the spacing between the prism-shaped geometric structures is 4.0 mm, the cross-sectional length of the prism-shaped geometric structures is 2.5 mm, the height of the prism-shaped geometric structures is 0.8 mm, the prism-shaped geometric structures are arranged on the side of the intruding formation, the vertical distance between the center line of the prism and the center of the PDC is 4.0 mm, and the convex-shaped geometric structures are arranged in the chip removal area behind the prism-shaped geometric structures.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The polycrystalline diamond layer surface employs a composite biomimetic structure combining convex and prismatic shapes. Both can significantly improve the wear resistance of the board surface and reduce mass wear. However, the total wear of individual units in the convex structure is very large, while the wear of individual units in the prismatic structure is very small. Therefore, combining and arranging the convex and prismatic shapes alternately can significantly improve wear resistance while minimizing the wear of individual structural units, thereby increasing the service life of the composite sheet.

[0018] A TiMoTa multi-component transition layer is sputtered onto the surface of diamond micropowder. Ti, Mo, and Ta are all strong carbide-forming elements, readily reacting with C during diamond deposition to form a dense nano-carbide layer at the interface. This inhibits Co diffusion from the matrix and hinders C atom diffusion into the transition layer, enabling rapid diamond nucleation at the interface and effectively enhancing interfacial bonding strength. Furthermore, its hardness and coefficient of thermal expansion are similar to those of diamond and cemented carbide. Ta exhibits good compatibility with both diamond and cemented carbide and has a dense structure, which is beneficial for improving the bending strength and hardness of cemented carbide. Mo plays a positive role in promoting diamond nucleation (nucleation density higher than 10¹⁴ / m³). 2 The addition of Ti (with an HCP structure) can improve the growth rate of diamond coatings. Both Mo and Ta are BCC structural elements with excellent mechanical properties. When Ti is added (at a temperature less than 882.5℃), the room temperature plasticity of the alloy can be effectively improved, giving the multi-component alloy layer a higher resistance to crack propagation.

[0019] The polycrystalline diamond layer and the cemented carbide substrate are connected by tenons, a traditional mortise and tenon joint. Tenons are vertical connecting components that ensure the stability of the vertical structure and prevent horizontal slippage. This is particularly important for small-scale components, where tenons significantly improve overall stability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the polycrystalline diamond composite sheet provided in an embodiment of the present invention; Figure 2 This is a planar schematic diagram of the composite biomimetic geometric structure provided in an embodiment of the present invention.

[0022] In the diagram, 1 is the polycrystalline diamond layer; 2 is the cemented carbide matrix; 3 is the tenon; 4 is the sea eye; 5 is the convex-shaped geometric structure; and 6 is the prismatic geometric structure. Detailed Implementation

[0023] 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.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] First, the diamond micropowder was acid-washed and alkali-washed, then rinsed 2-3 times with distilled water. The acid and alkali washes were performed by boiling the diamond micropowder in 10 wt.% NaOH and 30 wt.% HNO3 solutions for 30 min, respectively. Then, a TiMoTa transition layer was prepared on the diamond micropowder surface using a dual-glow plasma surface alloying (DGPSA) device. A deposition time of 30 min and a deposition temperature of 830℃ were selected as the optimized deposition parameters for the TiMoTa transition layer. Based on these parameters, a TiMoTa diffusion layer was prepared. First, the TiMoTa transition layer was prepared in the DGPSA device. After the polarity was turned on, glow discharge was distributed and covered the TiMoTa target and the surface of the diamond micropowder. Due to the potential difference, the TiMoTa alloy was sputtered from the target under argon ion bombardment and adsorbed and deposited on the surface of the diamond micropowder. Simultaneously, due to the Ar... + The bombardment of the diamond micropowder surface heats the substrate to 800°C, causing the TiMoTa adsorbed on the micropowder to diffuse inwards, forming a TiMoTa transition layer on the diamond micropowder surface consisting of a TiMoTa deposition layer and a TiMoTa gradient diffusion layer. Subsequently, reverse plasma sputtering is performed by reversing the voltage between the source electrode and the workpiece cathode. The workpiece voltage is gradually increased from 300-450V to 600-750V, while the source voltage is decreased from 600-750V to 300-450V. Under the electric field of the two high-voltage power supplies, the introduced argon gas is excited and ionized into argon ions. Driven by the high-voltage electric field, Ar... + The workpiece surface is bombarded by moving objects. With the Ar... + The workpiece is continuously bombarded, sputtering the TiMoTa deposited on the TiMoTa layer, leaving only the diffusion layer. Different thicknesses of TiMoTa diffusion layers can be obtained by varying the backsputtering time. During the backsputtering stage, the substrate temperature is measured using an infrared thermometer (OIT60). The substrate temperature is consistently maintained at 800℃, and the potential difference between the source electrode and the workpiece cathode is 300V. The diamond powder particle size is maintained at 20μm-25μm, and the thickness of the sputtered TiMoTa multi-component transition layer is 0.1μm-5μm.

[0026] The cemented carbide was ultrasonically treated in anhydrous ethanol for 30 minutes to remove surface impurities. The sputtered diamond powder and the treated cemented carbide matrix were then placed in a metal container and pressed into tablets to obtain the composite material. The metal container was either a molybdenum container or a tantalum container. The composite material, along with the encased metal container, was then assembled with a pyrophyllite assembly block to form a block. The sintered body is then placed in a six-sided press for high-temperature and high-pressure sintering. The pressure is initially increased to 6.2-7.2 GPa at a rate of 0.5-1 GPa / min, followed by a high-temperature sintering process at a rate of 40-50°C / s. After holding at 1420°C for 100-120 seconds, the temperature is increased to 1620-1780°C within 40-50 seconds. Following sintering, the temperature is reduced to 680°C at a rate of 20-25°C / s, held for 6-9 minutes, and then cooled to room temperature. The pressure is then reduced to atmospheric pressure at a rate of 0.2-0.9 GPa / min. The sintered body is held at this temperature for a predetermined time to obtain the sintered body. The sintered body is then removed from the six-sided press and held at this temperature for 240 seconds. It is then cooled to room temperature at a rate of 30°C / s, and finally depressurized to atmospheric pressure at a rate of 1 GPa / min. Remove the container covering the surface and perform grinding and polishing to obtain the high-temperature resistant and wear-resistant polycrystalline diamond composite sheet.

[0027] To verify the actual working performance of the polycrystalline diamond composite sheet described in this invention, its performance was compared with that of a commercially available conventional planar PDC composite sheet under the same conditions. The tests mainly included two parts: abrasion resistance test and impact resistance test. The embodiment uses a Ф19mm biomimetic PDC composite sheet prepared with the structure described in this invention. The surface has discontinuous ridge-like patterns and an array of elliptical convex bumps, and the diamond layer thickness is 3.0mm. The comparative example uses a Ф19mm conventional planar PDC composite sheet prepared with the same material and sintering process, with a diamond layer thickness of 2.0mm.

[0028] Wear resistance testing method (grinding test): A vertical lathe wear test method was used. A modified high-rigidity vertical CNC lathe was employed. A dense, homogeneous natural granite cylinder (compressive strength approximately 160-200 MPa) was selected as the cutting material. The spindle speed was 60 r / min; the depth of cut (ap) was 1.0 mm; the feed rate was 0.3 mm / r; and water cooling was used to simulate drilling fluid cooling. This method simulates the cutting conditions of a drill bit downhole, primarily testing the volume loss of the composite material during continuous cutting of hard rock. After cutting a certain volume of granite, the wear volume of the composite material was measured. The wear ratio calculation formula is: E =V rock / V pdc .in, Vpdc This represents the volume of wear on the composite sheet. E The higher the value, the better the wear resistance.

[0029] Impact resistance testing method (falling hammer impact test): The test is conducted using a falling hammer impact testing machine. The composite sheet is fixed on a specific fixture, and the impact angle is adjusted to a cutting angle of 15°~20°. An electromagnet is used to lift a hammer of a certain mass to a predetermined height, and after release, it falls freely to impact the cutting edge of the composite sheet. The "cumulative energy method" is used. The initial impact energy is set to 10J. If the sample is not damaged, the impact energy is increased in increments of 5J until visible cracks appear on the surface of the composite sheet, a chipped piece greater than 1mm is formed, or the substrate is exposed, which is considered a failure. This method is used to evaluate the ability of the diamond layer of the composite sheet to resist chipping or delamination when subjected to instantaneous high-energy impact loads.

[0030] Based on the above testing method, the test results of the embodiments and comparative examples of the present invention are shown in Table 1, where test numbers 1-3 are the test results of the embodiments, and 4-6 are the test results of the comparative examples.

[0031] Table 1 Performance test results of polycrystalline diamond

[0032] As can be seen from the results of the examples and comparative examples, the present invention can significantly improve the performance of polycrystalline diamond composite sheets under relatively mild reaction conditions compared to the comparative examples.

[0033] See Figure 1 and Figure 2 As shown, for the structure of polycrystalline diamond composite sheets, the surface geometric features of the clam shell, pangolin scale, and comb-scallop shell were first extracted to establish geometric mathematical models of convex-hull geometric structure 5 and prismatic geometric structure 6. The convex-hull geometric structure 5 has a spacing of 4.0 mm, a major axis of 3 mm, a minor axis of 2 mm, and a height of 0.6 mm. The prismatic geometric structure 6 has a spacing of 4.0 mm, a cross-sectional length of 2.5 mm, and a height of 0.8 mm. The prismatic geometric structure 6 is located on one side of the intruded stratum, with the prismatic centerline perpendicular to the PDC center at a distance of 4.0 mm. The convex-hull geometric structure 5 is located in the chip removal area behind the prismatic geometric structure 6. Figure 2 The region excluding the prismatic geometric structure 6.

[0034] The cemented carbide substrate 2 and the polycrystalline diamond layer 1 are connected by tenons. First, a small internal "sea eye" 4 with a larger external diameter is formed in the cemented carbide substrate 2. Then, a small head and a large root tenon 3 is formed in the polycrystalline diamond layer 1. The sea eye 4 and the tenon 3 have the same external curve design. During assembly, the polycrystalline diamond layer 1 is inserted into the cemented carbide substrate 2 in one go.

[0035] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a polycrystalline diamond composite sheet, characterized in that, include: 1) Micron powder cleaning: After acid washing and alkali washing, the diamond micron powder is cleaned with distilled water at high temperature 2-3 times; 2) Transition Layer Preparation: A TiMoTa transition layer was prepared on the surface of diamond micropowder using a DGPSA device. The TiMoTa transition layer comprises a TiMoTa deposition layer and a TiMoTa gradient diffusion layer. The TiMoTa gradient diffusion layer is prepared by exciting Ar... + Argon gas was reverse sputtered to obtain a TiMoTa transition layer containing only the TiMoTa deposited layer. 3) Finished product preparation: The cemented carbide matrix is ​​ultrasonically treated in an anhydrous ethanol environment for 30 minutes. The diamond micro powder from step 2) and the ultrasonically treated cemented carbide matrix are loaded into a metal container and pressed into a sheet to obtain a composite material. The composite material is then assembled into a block along with the metal container and the pyrophyllite assembly block, and sintered in a six-sided press. After sintering, the block is kept at a constant temperature to obtain a sintered body. The metal container is a molybdenum container or a tantalum container. The sintered body is taken out of the six-sided press for cooling and depressurization. After removing the metal container covering the surface, it is ground and polished to obtain a polycrystalline diamond composite sheet. Step 2) specifically includes: Optimized TiMoTa transition layer deposition parameters were selected for the preparation of the TiMoTa diffusion layer. First, the TiMoTa transition layer was prepared in a DGPSA device. After the bipolar power supply was turned on, glow discharge was distributed and covered the TiMoTa target and the surface of diamond micropowder, forming a TiMoTa transition layer consisting of a TiMoTa deposition layer and a TiMoTa gradient diffusion layer. The voltage between the source electrode and the workpiece cathode was reversed for reverse plasma sputtering. The substrate temperature was measured using an infrared thermometer. Under the electric field of the two high-voltage power supplies, the introduced argon gas was excited and ionized into Ar. + Under the drive of a high-voltage electric field, a TiMoTa transition layer containing only a TiMoTa deposition layer was prepared.

2. The method for preparing a polycrystalline diamond composite sheet according to claim 1, characterized in that, In step 1), the acid washing and alkaline washing are performed by boiling the diamond micro powder for 30 minutes with 10 wt.% NaOH and 30 wt.% HNO3 solutions, respectively.

3. The method for preparing a polycrystalline diamond composite sheet according to claim 2, characterized in that, A deposition time of 30 min and a deposition temperature of 830 ℃ were selected as the optimized deposition parameters for the TiMoTa transition layer. During reverse sputtering, Ar + The diamond powder was bombarded, which heated it to 800°C and held it thereafter.

4. The method for preparing a polycrystalline diamond composite sheet according to claim 3, characterized in that, During reverse sputtering, the workpiece voltage is increased from 300-450V to 600-750V, while the source voltage is decreased from 600-750V to 300-450V, resulting in a potential difference of 300V between the source and the workpiece cathode.

5. The method for preparing a polycrystalline diamond composite sheet according to claim 4, characterized in that, The diamond micropowder has a particle size of 20μm-25μm, and the sputtered TiMoTa transition layer has a thickness of 0.1μm-5μm.

6. The method for preparing a polycrystalline diamond composite sheet according to claim 5, characterized in that, In step 3), during sintering, the pressure is first increased to a sintering pressure of 6.2 GPa-7.2 GPa at a pressurization rate of 0.5 GPa / min-1 GPa / min, and the temperature is increased at a rate of 40℃ / s-50℃ / s for sintering. After holding at 1420℃ for 100s-120s, the temperature is increased to a sintering temperature of 1620℃-1780℃ within 40s-50s. After sintering, the temperature is decreased to 680℃ at a rate of 20℃ / s-25℃ / s, held for 6min-9min, and then reduced to room temperature. Finally, the pressure is reduced to atmospheric pressure at a rate of 0.2 GPa / min-0.9 GPa / min.

7. The method for preparing a polycrystalline diamond composite sheet according to claim 6, characterized in that, Step 3) After sintering, hold at the temperature for 240 seconds, cool down to room temperature at a rate of 30℃ / s, and then depressurize to atmospheric pressure at a rate of 1GPa / min.

8. A method for preparing polycrystalline diamond composite sheets according to any one of claims 1-7, characterized in that, The polycrystalline diamond composite sheet comprises a polycrystalline diamond layer and a cemented carbide matrix; A tenon is set on one side of the polycrystalline diamond layer, and a corresponding sea eye is set on the cemented carbide substrate. The size of the tenon matches the size of the sea eye, and the tenon is inserted into the sea eye to form a tenon foot. A composite biomimetic structure is provided on the other side of the polycrystalline diamond layer. The composite biomimetic structure is an alternating convex hull geometric structure and a prism geometric structure.

9. The polycrystalline diamond composite sheet according to claim 8, characterized in that, The convex-shaped geometric structure has a spacing of 4.0 mm, a major diameter of 3 mm, a minor diameter of 2 mm, and a height of 0.6 mm. The prism-shaped geometric structure has a spacing of 4.0 mm, a cross-sectional length of 2.5 mm, and a height of 0.8 mm. The prism-shaped geometric structure is located on the side that penetrates the formation, with the center line of the prism perpendicular to the center of the PDC circle at a distance of 4.0 mm. The convex-shaped geometric structure is located in the chip removal area behind the prism-shaped geometric structure.

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