A sealed cobalt removal tool, method, reagent and polycrystalline diamond composite sheet

Abstract

The present application discloses a sealed cobalt removal tool, method, reagent and polycrystalline diamond composite sheet. The tool comprises a sealing sleeve, a clamping mechanism and a pressing mechanism. The sealing sleeve is used to be sleeved on the outer wall of the workpiece, the clamping mechanism is sleeved on the outer wall of the sealing sleeve, the clamping mechanism is used to provide a first pressure to the sealing sleeve, the pressing mechanism is arranged on the top of the sealing sleeve, the pressing mechanism is used to provide a second pressure to the sealing sleeve, an inner cavity for containing chemical reagents is provided inside the pressing mechanism, and the top of the workpiece can extend into the inner cavity. The present application has the advantages of increasing the overall service life of the tool, increasing the reaction speed of the chemical reagents, the cobalt removal depth can reach more than 1200um, and meeting the demand for ultra-deep stripping of the workpiece.

Description

Technical Field

[0001] The present application relates to the technical field of cobalt removal, and in particular to a sealed cobalt removal tool, method, reagent and polycrystalline diamond composite sheet. Background Art

[0002] As a key working component in crude oil and natural gas extraction, and as a material that directly shears and crushes the rock structure, polycrystalline diamond composites play a decisive role in the drilling efficiency of the entire drill bit. Due to the extreme properties of underground drilling conditions, the polycrystalline diamond composite layer needs to have the best material properties to achieve the mining task, including extremely high hardness, toughness and thermal stability. The carbon atom arrangement structure of diamond itself provides the ultra-high hardness property of the polycrystalline diamond composite layer; the microscopic grain boundary interface of polycrystalline bonding and the network structure of metal catalysts existing between micron-sized grains provide the necessary toughness properties of the polycrystalline diamond composite layer; with the continuous improvement of drilling technology and equipment level, the speed of the drill bit and the pressure at the tip of the drill bit continue to increase, which puts forward unprecedented requirements for the thermal stability of the diamond composite layer under direct contact with the rock surface and high pressure and high speed working conditions. In the high temperature and high pressure synthesis process of polycrystalline diamond composites, the eighth group transition metals are usually used as catalysts to reduce the temperature and pressure required for the formation of diamond crystal phases, so as to achieve the engineering technical indicators that can be achieved by existing presses, thereby completing the entire synthesis preparation process. However, the transition metal elements infiltrated in polycrystalline diamond materials will cause local stress concentration in actual drilling applications due to the difference in thermal expansion coefficient with the diamond body, and the phase change catalytic properties of the transition metal itself will catalytically transform the diamond phase into a more stable graphite phase under normal pressure when the temperature reaches 700 degrees Celsius, thereby seriously reducing the thermal stability of the diamond composite material.

[0003] With the continuous improvement of drilling technology and performance requirements mentioned above, the industry's demand for the hardness, toughness and thermal stability of diamond composite layers has also increased significantly. While workpiece manufacturers are promoting the hardness and toughness of the composite layer by improving the process conditions of the high temperature and high pressure synthesis process, the microstructure of the composite layer and the overall tightness of the arrangement between the micrograins are also greatly improved, so that the catalytic metal phase remaining in the diamond composite layer during the high temperature and high pressure synthesis process leaves a finer pore space, making them more difficult to contact with the chemical reagents used to remove the metal phase, making it more difficult to achieve the required thermal stability than before. The significant extension of the time required for this key processing process has put tremendous pressure on the production cycle of workpiece manufacturers and drill bit manufacturers to prepare end products. At present, when the cobalt removal device used for workpieces is sealed for cobalt removal, due to the relatively low service life of the cobalt removal device, the reaction time of the chemical reagent and the cobalt removal layer of the composite sheet is short, which makes it difficult to remove the cobalt removal layer of the composite sheet to more than 1000μm, which cannot meet the current market demand for ultra-deep diamond removal to increase the service life of diamond. Summary of the invention

[0004] The main purpose of the present application is to provide a sealed cobalt removal tool, method, reagent and polycrystalline diamond composite sheet, aiming to solve the technical problem that the service life of the existing workpiece cobalt removal device is relatively short, resulting in the cobalt removal depth of the composite sheet cobalt removal layer not meeting the requirements.

[0005] To achieve the above-mentioned objectives, the present application provides a sealed cobalt removal tooling, comprising a sealing sleeve, a clamping mechanism and a pressing mechanism, the sealing sleeve being used to be sleeved on the outer wall of the workpiece, the clamping mechanism being sleeved on the outer wall of the sealing sleeve, the clamping mechanism being used to provide a first pressure to the sealing sleeve, the pressing mechanism being arranged at the top of the sealing sleeve, the pressing mechanism being used to provide a second pressure to the sealing sleeve, an inner cavity for containing chemical reagents being opened inside the pressing mechanism, and the top of the workpiece can extend into the inner cavity.

[0006] Optionally, the clamping mechanism comprises at least two groups of detachably connected clamping blocks, inner walls of the clamping blocks are provided with clamping grooves, and the sealing sleeve and the workpiece are both located between the clamping grooves.

[0007] Optionally, the sealing sleeve includes a sleeve for accommodating the workpiece, a first boss extending outward is arranged at the top of the sleeve, the clamping groove includes a first arc groove contacting the outer wall of the sleeve, and a first step groove cooperating with the first boss is arranged at the top of the first arc groove.

[0008] Optionally, the bottom of the sealing sleeve is closed or has an opening.

[0009] Optionally, the sealing sleeve is annular, and the outer diameter of the sealing sleeve decreases from top to bottom. The clamping groove includes a second arc groove in contact with the outer wall of the workpiece, and the top of the second arc groove is provided with an inverted cone step groove that cooperates with the sealing sleeve.

[0010] Optionally, the pressing mechanism includes a receiving block, an inner cavity is opened inside the receiving block, and a sealing gasket for sealing the inner cavity is arranged on the top of the receiving block.

[0011] Optionally, a second boss extending into the clamping groove is provided at the bottom of the receiving block, and the second boss is located at the top of the sealing sleeve.

[0012] Optionally, a packaging mechanism is further included, and the sealing sleeve, the clamping mechanism and the pressing mechanism are all located inside the packaging mechanism.

[0013] Optionally, the packaging mechanism includes a base with a accommodating cavity formed in the base, the sealing sleeve and the clamping mechanism are both located in the accommodating cavity, a hollow pressing block is provided on the outer wall of the base, the pressing mechanism is simultaneously located inside the base and the pressing block, a packaging cover is provided on the outer wall of the pressing block, and the packaging cover is pressed against the top of the pressing mechanism.

[0014] Optionally, the clamping block includes an internal threaded sleeve, which is threadedly connected to the base, a clamping boss extending inward is connected to the top of the internal threaded sleeve, a second step groove cooperating with the clamping boss is opened on the outer wall of the clamping mechanism, an external threaded sleeve is connected to the top of the clamping boss, and the external threaded sleeve is threadedly connected to the packaging cover.

[0015] Optionally, the top surface of the workpiece protrudes from the top surface of the sealing sleeve and the protrusion height is H, where H=600-800 μm.

[0016] Optionally, the sealing sleeve and the sealing gasket are made of organic material and / or inorganic material; wherein,

[0017] Organic materials include one or more of engineering plastics, rubber, fluorine-containing plastics or resins;

[0018] The inorganic material includes one or more of metal, metal oxide or nitride, non-metal, non-metal oxide or nitride.

[0019] Optionally, the inner wall of the inner cavity is provided with a corrosion-resistant layer, and the material of the corrosion-resistant layer includes one or more of fluorine-containing plastics, resins, metals, metal oxides or nitrides, non-metals, and non-metal oxides or nitrides.

[0020] Optionally, the Young's modulus of the materials used for the sealing sleeve, the sealing gasket and the receiving block is greater than 2.3 GPa;

[0021] Preferably, the Young's modulus of the material used is greater than 50 GPa;

[0022] Preferably, the Young's modulus of the material used is greater than 200 GPa.

[0023] Optionally, the thermal expansion coefficient of the materials of the sealing sleeve and the sealing gasket is greater than three times the maximum thermal expansion coefficient of the materials of the base, the receiving block and the packaging cover; preferably, greater than five times.

[0024] Optionally, the physical properties of the material used for the receiving block are: flexural strength ≥ 200 MPa, elastic modulus ≥ 250 Gpa, Poisson's ratio 0.2-0.25, and porosity ≤ 0.2%.

[0025] Optionally, the theoretical density of the material used for the sealing sleeve, the sealing gasket and the containing block is greater than 90%; preferably, the theoretical density of the material used is greater than 95%.

[0026] A cobalt removal method using the sealed cobalt removal tool comprises the following steps:

[0027] Installing the workpiece to be decobalted into the sealed decobalting tooling;

[0028] The sealing and decobalting tool is heated at a temperature of 50 to 350° C.;

[0029] The heated sealed cobalt removal tool is taken out and cooled to room temperature;

[0030] Disassembling the sealed cobalt removal tooling and pouring out the chemical reagent in the inner cavity;

[0031] Continue to disassemble the sealing cobalt removal tooling and take out the workpiece after cobalt removal;

[0032] The decobalting depth of the workpiece is detected after decobalting.

[0033] Optionally, in the step of heating the sealed decobaltizing tooling at a heating temperature of 50 to 350° C., the heating method is one or more of water bath, oil bath, gas bath, microwave heating, resistance wire heating, oven heating, electromagnetic induction heating or infrared heating.

[0034] Optionally, the step of installing the workpiece to be decobalted into the sealed decobalting tooling comprises:

[0035] placing the workpiece into the base;

[0036] Sleeving the sealing sleeve on the workpiece;

[0037] Clamping the sealing sleeve by the clamping mechanism;

[0038] Assembling the pressing mechanism to the top of the sealing sleeve;

[0039] Then the pressing block is screwed into the outer wall of the base until the pressing boss abuts against the second step groove;

[0040] adding chemical reagents into the inner cavity;

[0041] The packaging cover is screwed into the outer wall of the external threaded sleeve until the packaging cover is tightly pressed against the top of the clamping mechanism.

[0042] Optionally, in the step of adding chemical reagents into the inner cavity, the amount of the chemical reagents added is 1 / 5 to 4 / 5 of the volume of the inner cavity.

[0043] Optionally, after the step of disassembling the sealed cobalt removal tooling and pouring out the chemical reagent in the inner cavity, the following steps are also included:

[0044] Repeatedly clean the residual chemical reagents in the inner cavity with clean water.

[0045] Optionally, before the step of continuing to disassemble the sealed cobalt-removing tool and taking out the workpiece after the cobalt removal, the following steps are also included:

[0046] Ultrasonic cleaning of the workpiece after decobalting;

[0047] The cleaned workpiece is then dried.

[0048] A decobaltizing reagent used in the decobaltizing method comprises, by weight, 24-48 parts of hydrofluoric acid, 24-30 parts of nitric acid and 32-40 parts of distilled water.

[0049] Optionally, the decobaltizing agent includes 36 parts of hydrofluoric acid, 27.2 parts of nitric acid and 36.8 parts of distilled water, calculated by mass.

[0050] A polycrystalline diamond composite sheet prepared according to the decobalting method comprises a substrate, a non-decobalting layer and a decobalting layer connected in sequence from bottom to top, wherein the flat decobalting depth of the decobalting layer is h1, h1≥1200um, and the edge decobalting depth of the decobalting layer is h2, h2≤2h1.

[0051] Optionally, the inclination angle of the boundary surface between the non-decobalted layer and the decobalted layer is a, and a<45°.

[0052] Optionally, the cross-section of the substrate, the non-decobaltized layer and the decobaltized layer is any one of a circle, a sector, a regular polygon and an irregular polygon.

[0053] The beneficial effects that this application can achieve are as follows:

[0054] The present application can provide a first pressure (i.e., lateral pressure) on the sealing sleeve under the clamping action of the clamping mechanism, and at the same time, realize a second pressure (i.e., vertical pressure) on the sealing sleeve through the pressing mechanism, thereby ensuring the sealing effect between the sealing sleeve and the workpiece. After the tooling is heated as a whole, the thermal expansion coefficient of the sealing sleeve is much greater than that of the adjacent components, and under the joint action of the clamping mechanism and the pressing mechanism, the sealing sleeve is not easily damaged, thereby ensuring the sealing effect under the inner cavity pressure condition. After the chemical reagent is heated to a temperature exceeding the boiling point under normal pressure, the increase in temperature can increase the reaction rate of decobalting, and the inner cavity pressure increases with the increase in temperature, further increasing the reaction rate. At the same time, due to the dual effects of pressure and ensuring the sealing effect, the depth of the downward reaction of the chemical reagent is further increased. Therefore, the first pressure and the second pressure are applied to the sealing sleeve at the same time to increase its service life, thereby ensuring the sealing effect and increasing the reaction time of the chemical reagent. After testing, the decobalting depth of the workpiece prepared by the present application can reach more than 1200um, meeting the needs of ultra-deep decobalting of workpieces such as diamond. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0056] Figure 1 This is a schematic structural diagram of a sealed cobalt removal tool in an embodiment of the present application;

[0057] Figure 2 It is a schematic diagram of another structure of a sealed cobalt removal tool in an embodiment of the present application;

[0058] Figure 3 This is a schematic diagram of the explosion structure of a sealed cobalt removal tool in an embodiment of the present application;

[0059] Figure 4 This is a schematic diagram of the assembly structure of the workpiece and the sealing sleeve in the embodiment of the present application;

[0060] Figure 5 This is a schematic structural diagram of a sealing sleeve with its bottom half open in an embodiment of the present application;

[0061] Figure 6 This is a schematic structural diagram of a sealing sleeve with its bottom half open in an embodiment of the present application;

[0062] Figure 7 This is a schematic structural diagram of the sealing sleeve when the bottom is fully open in the embodiment of the present application;

[0063] Figure 8This is a schematic diagram of another structural form of the sealing sleeve in the embodiment of the present application (top view);

[0064] Fig. 9 This is a schematic structural diagram of a sealing sleeve in an annular shape in an embodiment of the present application;

[0065] Fig.10 It is a schematic diagram of the three-dimensional structure of the sealing sleeve in the embodiment of the present application;

[0066] Fig.11 It is a structural schematic diagram of the clamping mechanism in the embodiment of the present application;

[0067] Fig.12 for Fig.11 A schematic diagram of a top view of the structure;

[0068] Fig.13 is a schematic diagram of another structure of the clamping mechanism in the embodiment of the present application;

[0069] Fig.14 It is a structural schematic diagram of the clamping mechanism in the embodiment of the present application;

[0070] Fig.15 A schematic diagram of a process for removing cobalt according to an embodiment of the present application;

[0071] Fig.16 This is a time-cobalt removal depth relationship curve diagram of the sealed cobalt removal tooling under 70° C. heating conditions in an embodiment of the present application;

[0072] Fig.17 This is a time-cobalt removal depth relationship curve diagram of the sealed cobalt removal tooling under 120° C. heating conditions in an embodiment of the present application;

[0073] Fig.18 It is a time-cobalt removal depth relationship curve diagram of the sealed cobalt removal tool under the heating condition of 170° C. in the embodiment of the present application;

[0074] Fig.19 It is a time-cobalt removal depth relationship curve diagram of the sealed cobalt removal tool under the heating condition of 200° C. in the embodiment of the present application;

[0075] Fig. 20 This is a diagram showing the cobalt removal effect of a polycrystalline diamond composite sheet in an embodiment of the present application.

[0076] Reference numerals:

[0077] 100-sealing sleeve, 110-sleeve, 120-first boss, 200-clamping mechanism, 210-clamping block, 211-clamping groove, 2111-first arc groove, 2112-first step groove, 2113-second arc groove, 2114-inverted cone step groove, 300-pressing mechanism, 310-receiving block, 311-inner cavity, 312-second step groove, 320-sealing gasket, 330-second boss, 400-packaging mechanism, 410-base, 411-accommodating cavity, 420-pressing block, 421-inner thread sleeve, 422-pressing boss, 423-external thread sleeve, 430-packaging cover, 500-workpiece, 510-substrate, 520-unde-cobaltized layer, 530-de-cobaltized layer.

[0078] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0079] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0080] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0081] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0082] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0083] Example 1

[0084] Reference Figure 1-Figure 14 The present embodiment provides a sealed cobalt removal tool, including a sealing sleeve 100, a clamping mechanism 200 and a pressing mechanism 300. The sealing sleeve 100 is used to be sleeved on the outer wall of the workpiece 500, the clamping mechanism 200 is sleeved on the outer wall of the sealing sleeve 100, the clamping mechanism 200 is used to provide a first pressure to the sealing sleeve 100, the pressing mechanism 300 is arranged at the top of the sealing sleeve 100, the pressing mechanism 300 is used to provide a second pressure to the sealing sleeve 100, and an inner cavity 311 for containing chemical reagents is opened inside the pressing mechanism 300, and the top of the workpiece 500 can extend into the inner cavity 311.

[0085] The core of improving the reaction time of chemical reagents in the decobalting process is to ensure the sealing of the decobalting device. The prior art only uses a sealing ring for sealing at the decobalting position of the workpiece. However, due to the service life of the sealing ring or the blockage of the channel formed by the chemical reaction by the generated salt, it is difficult to decobaltize the plane of the workpiece to a depth of more than 1000 μm. Therefore, in this embodiment, the first pressure (i.e., lateral pressure) on the sealing sleeve 100 can be provided by the clamping action of the clamping mechanism 200, and the second pressure (i.e., vertical pressure) on the sealing sleeve 100 is achieved by the clamping mechanism 300, thereby ensuring the sealing effect between the sealing sleeve 100 and the workpiece 500. After the tooling is heated as a whole, the thermal expansion coefficient of the sealing sleeve 100 is much greater than that of the adjacent components, and during the clamping, the sealing sleeve 100 is compressed by the clamping mechanism 300. Under the joint action of the mechanism 200 and the clamping mechanism 300, the sealing sleeve 100 is not easy to be damaged, ensuring the sealing effect under the pressure condition of the inner cavity 311. After the chemical reagent is heated to a temperature exceeding the boiling point under normal pressure, the temperature increase can increase the reaction rate of decobalting, and the pressure of the inner cavity 311 increases with the increase in temperature, further increasing the reaction rate. At the same time, due to the dual effects of the pressure and ensuring the sealing effect, the depth of the downward reaction is further increased. Therefore, the first pressure and the second pressure are applied to the sealing sleeve 100 at the same time to increase its service life, thereby ensuring the sealing effect and increasing the reaction time of the chemical reagent. After testing, the decobalting depth of the workpiece 500 prepared by the present application can reach more than 1200um, which meets the needs of ultra-deep decobalting of workpieces 500 such as diamonds.

[0086] As an optional embodiment, the clamping mechanism 200 includes at least two groups of detachably connected clamping blocks 210 , the inner walls of the clamping blocks 210 are provided with clamping grooves 211 , and the sealing sleeve 100 and the workpiece 500 are both located between the clamping grooves 211 .

[0087] In this embodiment, two clamping blocks 210 are generally provided, and the two clamping blocks 210 are connected together by bolts, that is, a detachable connection is realized, and a close fit between the sealing sleeve 100 and the workpiece 500 can be ensured, which plays a key role in protecting the hard alloy of the workpiece 500. The clamping force is also adjustable (that is, the radial pressure is adjustable). Different radial pressures can meet different cobalt removal processes, and can greatly increase the pressure of the inner cavity 311 during the cobalt removal process without causing corrosion to the workpiece 500 alloy. At the same time, it can adapt to the clamping of workpieces 500 with different outer diameters, has an adjustable function, a wide range of applications, and is convenient and quick to operate.

[0088] As an optional embodiment, the sealing sleeve 100 includes a sleeve 110 for accommodating a workpiece 500, a first boss 120 extending outward is arranged at the top of the sleeve 110, the clamping groove 211 includes a first arc-shaped groove 2111 in contact with the outer wall of the sleeve 110, and a first step groove 2112 cooperating with the first boss 120 is arranged at the top of the first arc-shaped groove 2111.

[0089] In this embodiment, the workpiece 500 is generally cylindrical, so the sealing sleeve 100 can be a round sleeve with an open top, which is convenient for directly placing the workpiece 500 into the sealing sleeve 100. At the same time, the sealing sleeve 100 is convenient for positioning and assembly through the cooperation of the first boss 120 and the first arc groove 2111. Here, the sealing sleeve 100 plays the role of sealing and protecting the interface of the cemented carbide of the workpiece 500 and the entire cemented carbide part.

[0090] It should be noted that the workpiece 500 may also be a structure with a fan-shaped, polygonal or other special-shaped cross section, and the sealing sleeve 100 can be matched according to the workpiece 500 of the corresponding shape. For example, for a workpiece 500 with a fan-shaped cross section, the sealing sleeve 100 has a corresponding fan-shaped cross section, and its internal cavity is also fan-shaped (such as Figure 8 As shown in FIG. 1 , the rest of the tooling parts do not need to be changed, and only the sealing sleeve 100 of the corresponding shape needs to be matched according to the shape of the workpiece 500, which has a certain degree of versatility. Therefore, the clamping mechanism 200 is used alone to provide lateral pressure to the sealing sleeve 100, and also has the key function of clamping sealing sleeves 100 of various shapes, which provides a prerequisite for the tooling to have the function of preparing workpieces 500 of various shapes.

[0091] As an optional embodiment, the bottom of the sealing sleeve 100 is closed or has an opening. When the bottom of the sealing sleeve 100 is open, it can be semi-open (such as Figure 5 or Figure 6 as shown) or fully open (as shown Figure 7 shown).

[0092] As another optional embodiment, the sealing sleeve 100 is annular (eg Fig. 9 and Fig.10 As shown), the outer diameter of the sealing sleeve 100 decreases from top to bottom, the clamping groove 211 includes a second arc groove 2113 in contact with the outer wall of the workpiece 500, and the top of the second arc groove 2113 is provided with an inverted cone step groove 2114 that cooperates with the sealing sleeve 100.

[0093] In this embodiment, the sealing sleeve 100 is arranged in a ring shape, which has a simpler structure and saves costs. At the same time, it can also achieve a sealing effect on the workpiece 500. During assembly, the sealing sleeve 100 is directly placed in the inverted conical step groove 2114, which is easy to assemble. The sealing sleeve 100 can be pressed downward by pressing down on the conical surface structure with a narrow top and a wide bottom. At this time, the clamping block 210 clamps the sealing sleeve 100 and the workpiece 500 at the same time through the clamping groove 211, and the clamping is more secure and stable.

[0094] It should be noted that the annular sealing sleeve 100 needs to be sleeved on the position of the workpiece 500 to be decobalted (the position close to the top of the workpiece 500).

[0095] As an optional embodiment, the clamping mechanism 300 includes a receiving block 310, an inner cavity 311 is opened inside the receiving block 310, and a sealing gasket 320 is arranged on the top of the receiving block 310 for sealing the inner cavity 311. A second boss 330 extending into the clamping groove 211 is arranged at the bottom of the receiving block 310, and the second boss 330 is located at the top of the sealing sleeve 100.

[0096] In this embodiment, the main function of the receiving block 310 is to generate pressure on the sealing sleeve 100, and to further press and protect the workpiece 500 through the second boss 330 that matches the radial size of the sealing ring, while accurately controlling the corner depth of the decobalting process, and forming an inner cavity 311 of the container bearing space after the assembly connection is completed, which is used to hold the chemical reagent solvent used for thermal stabilization treatment of the composite layer surface.

[0097] It should be noted that when the sealing sleeve 100 is in the shape of a circular sleeve 110, the second boss 330 is in a circular ring shape that matches the first step groove 2112. When the sealing sleeve 100 is annular, the outer diameter of the second boss 330 decreases from top to bottom to match the inverted tapered step groove 2114.

[0098] As an optional embodiment, it also includes a packaging mechanism 400, the sealing sleeve 100, the clamping mechanism 200 and the pressing mechanism 300 are all located in the packaging mechanism 400, the packaging mechanism 400 includes a base 410, a receiving cavity 411 is opened in the base 410, the sealing sleeve 100 and the clamping mechanism 200 are both located in the receiving cavity 411, the outer wall of the base 410 is provided with a hollow pressing block 420, the pressing mechanism 300 is simultaneously located inside the base 410 and the pressing block 420, the outer wall of the pressing block 420 is provided with a packaging cover 430, and the packaging cover 430 is pressed on the top of the pressing mechanism 300.

[0099] In this embodiment, the base 410 is used to hold the entire workpiece 500 and the clamping mechanism 200. The clamping block 420 can provide a second pressure to the clamping mechanism 300, so that the clamping mechanism 300 transmits the second pressure to the sealing sleeve 100. Finally, the clamping mechanism 300 is clamped by the packaging cover 430 to complete the assembly of the entire tooling. The overall sealing structure is stable and reliable with good sealing performance.

[0100] As an optional embodiment, the clamping block 420 includes an internal threaded sleeve 421, which is threadedly connected to the base 410, and the top of the internal threaded sleeve 421 is connected to a clamping boss 422 extending inward. The outer wall of the clamping mechanism 300 is provided with a second step groove 312 that cooperates with the clamping boss 422, and the top of the clamping boss 422 is connected to an external threaded sleeve 423, and the external threaded sleeve 423 is threadedly connected to the packaging cover 430.

[0101] In this embodiment, the clamping block 420 is threadedly connected to the base 410 through an internal threaded sleeve 421, and is threadedly connected to the packaging cover 430 through an external threaded sleeve 423. The outer wall of the base 410 is provided with an external thread that cooperates with the internal threaded sleeve 421, and the inner wall of the packaging cover 430 is provided with an internal thread that cooperates with the external threaded sleeve 423. When the clamping block 420 is screwed in, self-locking is achieved through the threaded connection, and when the clamping boss 422 is screwed into the second step groove 312, it can be ensured that the clamping boss 422 axially presses the receiving block 310 of the clamping mechanism 300, and the second pressure can be adjusted according to the screw-in depth of the clamping block 420, which meets the requirements of different decobaltization processes and has a wide range of applications.

[0102] As an optional embodiment, the top surface of the workpiece 500 protrudes from the top surface of the sealing sleeve 100 and the protrusion height is H, H = 600-800 μm, the protrusion height of the workpiece 500 is the part to be decobalted, and the boundary surface inclination angle a is related to the protrusion height H at 0. At this protrusion height H, the requirement that the boundary surface inclination angle a < 45° between the decobalted layer and the non-decobalted layer of the workpiece 500 can be met.

[0103] As an optional embodiment, the sealing sleeve 100 and the sealing gasket 320 are made of organic materials and / or inorganic materials;

[0104] Organic materials include one or more of engineering plastics, rubber, fluorine-containing plastics or resins;

[0105] The inorganic material includes one or more of metal, metal oxide or nitride, non-metal, non-metal oxide or nitride.

[0106] In this embodiment, the sealing sleeve 100 and the sealing gasket 320 are important components for ensuring sealing, so special requirements are placed on their materials, which need to have good anti-corrosion properties and meet usage requirements.

[0107] As an optional embodiment, the inner wall of the inner cavity 311 is provided with a corrosion-resistant layer, and the material making the corrosion-resistant layer includes one or more of fluoroplastics, resins, metals, metal oxides or nitrides, non-metals, non-metal oxides or nitrides, so as to improve the corrosion resistance of the inner cavity 311.

[0108] As an optional embodiment, the Young's modulus of the material used for the sealing sleeve 100, the sealing gasket 320 and the receiving block 310 is greater than 2.3 GPa;

[0109] Preferably, the Young's modulus of the material used is greater than 50 GPa;

[0110] Preferably, the Young's modulus of the material used is greater than 200 GPa.

[0111] In this embodiment, the three modulus values ​​of 2.3 GPa, 50 GPa and 200 GPa correspond to the strengths of engineering plastics, metal alloys and metal oxide ceramics, respectively. Considering the strength requirements and material costs of different materials, different materials can be selected as raw materials for making chemical solution container tooling.

[0112] As an optional embodiment, the thermal expansion coefficient of the material of the sealing sleeve 100 and the sealing gasket 320 is greater than three times the maximum thermal expansion coefficient of the material of the base 410, the receiving block 310 and the packaging cover 430; preferably, greater than five times.

[0113] When the sealing decobaltizing tool is heated, in order to improve its sealing performance, a material with a large thermal expansion coefficient is selected as the sealing gasket 320 and the sealing sleeve 100. When the temperature inside the inner cavity 311 rises and the pressure increases, the sealing gasket 320 and the sealing sleeve 100 also expand accordingly, and the sealing performance is improved.

[0114] As an optional implementation, the physical properties of the material used for the receiving block 310 are: flexural strength ≥ 200 MPa, elastic modulus ≥ 250 Gpa, Poisson's ratio 0.2-0.25, and porosity ≤ 0.2%.

[0115] As an optional implementation, the theoretical density of the material used for the sealing sleeve 100, the sealing gasket 320 and the receiving block 310 is greater than 90%; preferably, the theoretical density of the material used is greater than 95%.

[0116] Example 2

[0117] Reference Figure 1-Figure 15 This embodiment provides a cobalt removal method using the sealed cobalt removal tool described in Example 1, comprising the following steps:

[0118] Installing the workpiece 500 to be decobalted into the sealed decobalting tool;

[0119] The sealing and decobalting tool is heated at a temperature of 50 to 350° C.;

[0120] The heated sealed cobalt removal tool is taken out and cooled to room temperature;

[0121] Dismantle the sealed cobalt removal tooling and pour out the chemical reagent in the inner cavity 311;

[0122] Continue to disassemble the sealing decobalting tooling and take out the decobalted workpiece 500;

[0123] The decobalting depth of the workpiece 500 is detected after decobalting.

[0124] In this embodiment, when the sealed cobalt removal tooling described in Example 1 is used for cobalt removal, the obtained workpiece 500 can meet the process requirements of ultra-deep decobalting. The sealed cobalt removal tooling is subjected to cobalt removal depth tests at heating temperatures of 70°C, 120°C, 170°C and 200°C (taking cobalt removal to 1200um as an example), and the following is drawn: Figure 16-Figure 19 From the relationship curve shown, it can be seen that the higher the heating temperature, the shorter the time required to reach the cobalt removal depth of 1200um.

[0125] It should be noted that the data corresponding to the above relationship curve diagram only serves to illustrate the concept for a single type of workpiece 500. Different workpieces 500 will have different cobalt removal speed responses, but the overall concept is always applicable.

[0126] As an optional embodiment, in the step of heating the sealed decobaltizing tooling at a heating temperature of 50 to 350° C., the heating method is one or more of water bath, oil bath, gas bath, microwave heating, resistance wire heating, oven heating, electromagnetic induction heating or infrared heating.

[0127] As an optional embodiment, the step of installing the workpiece 500 to be decobalted into the sealed decobalting tool comprises:

[0128] Place the workpiece 500 into the base 410;

[0129] The sealing sleeve 100 is sleeved on the workpiece 500;

[0130] The sealing sleeve 100 is clamped by the clamping mechanism 200;

[0131] Assemble the pressing mechanism 300 to the top of the sealing sleeve 100;

[0132] Then, the pressing block 420 is screwed into the outer wall of the base 410 until the pressing boss 422 is pressed against the second step groove 312;

[0133] Adding chemical reagents into the inner cavity 311;

[0134] The packaging cover 430 is screwed into the outer wall of the external threaded sleeve 423 until the packaging cover 430 is pressed against the top of the pressing mechanism 300 .

[0135] As an optional embodiment, in the step of adding chemical reagents to the inner cavity 311, the amount of the chemical reagents added is 1 / 5 to 4 / 5 of the volume of the inner cavity 311. Since the decobalting chemical reagents contain volatile chemical components and water, during the heating process, the vaporization of the liquid will cause the internal pressure of the inner cavity 311 to rise sharply. When the amount of the chemical reagents exceeds 4 / 5 of the volume of the inner cavity 311, the remaining 1 / 5 of the space is insufficient to accommodate the vaporized chemical reagents, and the internal pressure will exceed the pressure that the tooling can withstand, resulting in the overflow of the decobalting reagents or the collapse of the sealed decobalting device; when the amount of the chemical reagents is less than 1 / 5 of the volume of the inner cavity 311, the amount of the chemical reagents is insufficient to achieve the target decobalting depth, so it is more reasonable to add 1 / 5 to 4 / 5 of the volume of the inner cavity 311.

[0136] As an optional implementation, after the step of disassembling the sealed cobalt removal tool and pouring out the chemical reagent in the inner cavity 311, the following steps are also included:

[0137] The residual chemical reagents in the inner cavity 311 are repeatedly cleaned with clean water.

[0138] Clean the inner cavity 311 in time to reduce the corrosive effect of chemical reagents and prepare for next use.

[0139] As an optional implementation, before the step of continuing to disassemble the sealed cobalt-removing tool and taking out the workpiece 500 after cobalt removal, the following steps are also included:

[0140] Performing ultrasonic cleaning on the workpiece 500 after decobalting;

[0141] The cleaned workpiece 500 is then dried.

[0142] In this embodiment, ultrasonic cleaning can wash out the decobaltizing chemical reagents in the gaps of the sealed decobaltizing tooling to prevent the decobaltizing chemical reagents from contacting and corroding the metal alloy substrate of the workpiece 500 when the workpiece 500 is removed. Then, drying the workpiece 500 can completely volatilize the residual decobaltizing chemical reagents.

[0143] Example 3

[0144] This embodiment provides a decobaltizing reagent for use in the decobaltizing method described in Embodiment 2, which comprises, by mass, 24 parts of hydrofluoric acid, 24 parts of nitric acid, and 32 parts of distilled water.

[0145] Example 4

[0146] This embodiment provides a decobaltizing reagent for use in the decobaltizing method described in Embodiment 2, which comprises, by mass, 36 parts of hydrofluoric acid, 27.2 parts of nitric acid, and 36.8 parts of distilled water.

[0147] Example 5

[0148] This embodiment provides a decobaltizing reagent for use in the decobaltizing method described in Embodiment 2, which comprises, by mass, 48 ​​parts of hydrofluoric acid, 30 parts of nitric acid, and 40 parts of distilled water.

[0149] Example 6

[0150] like Figure 4-Figure 10 as well as Fig. 20 As shown, this embodiment provides a polycrystalline diamond composite sheet prepared according to the decobalting method described in Example 2, including a substrate 510, a non-decobalted layer 520 and a decobalted layer 530 connected in sequence from bottom to top, the decobalting depth of the decobalted layer 530 is h1, h1≥1200um, the edge decobalting depth of the decobalted layer 530 is h2, h2≤2h1, and the thickness of the composite layer (i.e., the decobalted layer 530 plus the non-decobalted layer 520) is h3.

[0151] It should be noted that the flat-peel depth and edge-peel depth of the prepared polycrystalline diamond composite sheet are related to the protrusion height H during installation. For example, when the composite layer thickness needs to reach h3=2000um, the flat-peel depth h1=1200um, and the edge-peel depth h2=1500um, the protrusion height H=450-550um; when the composite layer thickness needs to reach h3=3000um, the flat-peel depth h1=1200um, and the edge-peel depth h2=2400um, the protrusion height H=700-900um; when the composite layer thickness needs to reach h3=4000um, the flat-peel depth h1=1500-2000um, and the edge-peel depth h2=3000-3500um, the protrusion height H=1500-1800um.

[0152] In addition, the boundary surface inclination angle between the non-decobalted layer 520 and the decobalted layer 530 is a, a<45°, so the polycrystalline diamond composite sheet in this embodiment meets the requirements of ultra-deep decobalting and boundary surface inclination angle a less than 45°, and is suitable for application scenarios with ultra-long service life.

[0153] As an optional embodiment, the cross-sections of the substrate 510, the non-decobaltized layer 520 and the decobaltized layer 530 are any one of circular, fan-shaped, regular polygonal and irregular polygonal. For example, the substrate 510, the non-decobaltized layer 520 and the decobaltized layer 530 all have a fan-shaped cross-section or other structures of the same shape. The substrate 510 may have a circular cross-section, and the non-decobaltized layer 520 and the decobaltized layer 530 may have a fan-shaped cross-section, thereby forming polycrystalline diamond composite sheets with various special structures to meet special usage requirements.

[0154] It should be noted that, when preparing polycrystalline diamond composite sheets of various shapes, a sealing sleeve 100 of a corresponding matching shape can be used in the tooling, and other parts of the tooling do not need to be changed. The tooling has high versatility and a wide range of applications.

[0155] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A sealed cobalt removal tool, characterized in that: include: A sealing sleeve, the sealing sleeve is used to be sleeved on the outer wall of the workpiece; A clamping mechanism, wherein the clamping mechanism is sleeved on the outer wall of the sealing sleeve and is used to provide a first pressure to the sealing sleeve; The clamping mechanism comprises at least two groups of detachably connected clamping blocks, the inner wall of the clamping block is provided with a clamping groove, and the sealing sleeve and the workpiece are both located between the clamping grooves; The sealing sleeve comprises a sleeve for accommodating the workpiece, a first boss extending outward is arranged at the top of the sleeve, the clamping groove comprises a first arc groove contacting the outer wall of the sleeve, and a first step groove cooperating with the first boss is arranged at the top of the first arc groove A clamping mechanism, the clamping mechanism is arranged at the top of the sealing sleeve, the clamping mechanism is used to provide a second pressure to the sealing sleeve, an inner cavity for containing chemical reagents is provided inside the clamping mechanism, and the top of the workpiece can extend into the inner cavity; The clamping mechanism comprises a receiving block, the inner cavity is opened inside the receiving block, and a sealing gasket for sealing the inner cavity is arranged on the top of the receiving block; The cobalt removal tool also includes a packaging mechanism, which includes a base, an outer wall of the base is provided with a hollow pressing block, the pressing mechanism is located inside the base and the pressing block at the same time, and an outer wall of the pressing block is provided with a packaging cover, and the packaging cover is pressed on the top of the pressing mechanism; The thermal expansion coefficient of the materials of the sealing sleeve and the sealing gasket is greater than three times the maximum thermal expansion coefficient of the materials of the base, the receiving block and the packaging cover.

2. The sealing and cobalt removal tool as claimed in claim 1, characterized in that: The bottom of the sealing sleeve is closed or has an opening.

3. The sealing and cobalt removal tool as claimed in claim 1, characterized in that: The sealing sleeve is annular, and the outer diameter of the sealing sleeve decreases from top to bottom. The clamping groove includes a second arc groove in contact with the outer wall of the workpiece, and the top of the second arc groove is provided with an inverted cone step groove matching with the sealing sleeve.

4. The sealing and cobalt removal tool as claimed in claim 1, characterized in that: A second boss extending into the clamping groove is arranged at the bottom of the receiving block, and the second boss is located at the top of the sealing sleeve.

5. The sealed cobalt removal tool as claimed in claim 1, characterized in that: The sealing sleeve, the clamping mechanism and the pressing mechanism are all located inside the packaging mechanism.

6. The sealing and cobalt removal tool as claimed in claim 5, characterized in that: An accommodating cavity is provided in the base, and the sealing sleeve and the clamping mechanism are both located in the accommodating cavity.

7. The sealing and cobalt removal tool as claimed in claim 6, characterized in that: The clamping block includes an internal threaded sleeve, which is threadedly connected to the base, a clamping boss extending inwardly is connected to the top of the internal threaded sleeve, a second step groove cooperating with the clamping boss is formed on the outer wall of the clamping mechanism, an external threaded sleeve is connected to the top of the clamping boss, and the external threaded sleeve is threadedly connected to the packaging cover.

8. The sealing and cobalt removal tool as claimed in claim 1, characterized in that: The top surface of the workpiece protrudes from the top surface of the sealing sleeve and the protrusion height is H, where H=600-800 μm.

9. The sealing and cobalt removal tool as claimed in claim 3, characterized in that: The sealing sleeve and the sealing gasket are made of organic material and / or inorganic material; wherein, The organic material includes one or more of engineering plastics, rubber, fluorine-containing plastics or resins; The inorganic material includes one or more of metal, metal oxide or nitride, non-metal, non-metal oxide or nitride.

10. The sealing and cobalt removal tool as claimed in claim 9, characterized in that: The inner wall of the inner cavity is provided with a corrosion-resistant layer, and the material of the corrosion-resistant layer includes one or more of fluorine-containing plastics, resins, metals, metal oxides or nitrides, non-metals, and non-metal oxides or nitrides.

11. The sealing and cobalt removal tool as claimed in claim 10, characterized in that: The Young's modulus of the materials used for the sealing sleeve, the sealing gasket and the receiving block is greater than 2.3 GPa.

12. The sealing and cobalt removal tool as claimed in claim 10, characterized in that: The Young's modulus of the materials used for the sealing sleeve, the sealing gasket and the receiving block is greater than 50 GPa.

13. The sealing and cobalt removal tool as claimed in claim 10, characterized in that: The Young's modulus of the materials used for the sealing sleeve, the sealing gasket and the receiving block is greater than 200 GPa.

14. The sealing and cobalt removal tool as claimed in claim 10, characterized in that: The thermal expansion coefficient of the materials of the sealing sleeve and the sealing gasket is greater than five times the maximum thermal expansion coefficient of the materials of the base, the receiving block and the packaging cover.

15. The sealed cobalt removal tool as claimed in claim 10, characterized in that: The physical properties of the material used for the receiving block are: flexural strength ≥ 200 MPa, elastic modulus ≥ 250 GPa, Poisson's ratio 0.2-0.25, and porosity ≤ 0.2%.

16. The sealing and cobalt removal tool as claimed in claim 10, characterized in that: The theoretical density of the materials used for the sealing sleeve, the sealing pad and the containing block is greater than 90%.

17. The sealing and cobalt removal tool as claimed in claim 16, characterized in that: The theoretical density of the materials used for the sealing sleeve, the sealing pad and the containing block is greater than 95%.

18. A method for removing cobalt using the sealed cobalt removal tool as claimed in claim 7, characterized in that: The following steps are involved: Installing the workpiece to be decobalted into the sealed decobalting tooling; The sealing and decobalting tool is heated at a temperature of 50-350° C.; The heated sealed cobalt removal tool is taken out and cooled to room temperature; Disassembling the sealed cobalt removal tooling and pouring out the chemical reagent in the inner cavity; Continue to disassemble the sealing cobalt removal tooling and take out the workpiece after cobalt removal; The decobalting depth of the workpiece is detected after decobalting.

19. The method for removing cobalt according to claim 18, characterized in that: In the step of heating the sealing decobaltizing tooling at a heating temperature of 50-350° C., the heating method is one or more of water bath, oil bath, gas bath, microwave heating, resistance wire heating, oven heating, electromagnetic induction heating or infrared heating.

20. The method for removing cobalt according to claim 18, characterized in that: The step of installing the workpiece to be decobalted into the sealed decobalting tooling comprises: placing the workpiece into the base; Sleeving the sealing sleeve on the workpiece; Clamping the sealing sleeve by the clamping mechanism; Assembling the pressing mechanism to the top of the sealing sleeve; Then the pressing block is screwed into the outer wall of the base until the pressing boss abuts against the second step groove; adding chemical reagents into the inner cavity; The packaging cover is screwed into the outer wall of the external threaded sleeve until the packaging cover is tightly pressed against the top of the clamping mechanism.

21. The method for removing cobalt according to claim 20, characterized in that: In the step of adding chemical reagents into the inner cavity, the amount of the chemical reagents added is 1 / 5 to 4 / 5 of the volume of the inner cavity.

22. The method for removing cobalt according to claim 18, characterized in that: After the step of disassembling the sealed cobalt removal tooling and pouring out the chemical reagent in the inner cavity, the following steps are also included: Use clean water to repeatedly clean the residual chemical reagents in the inner cavity.

23. The method for removing cobalt according to claim 18, characterized in that: Before the step of continuing to disassemble the sealed cobalt-removing tooling and taking out the workpiece after the cobalt removal, the following steps are also included: Ultrasonic cleaning of the workpiece after decobalting; The cleaned workpiece is then dried.

24. A polycrystalline diamond compact prepared by the cobalt removal method according to claim 18, characterized in that: It comprises a substrate, a non-decobaltized layer and a decobaltized layer which are sequentially connected from bottom to top, wherein the flat decobaltized layer has a depth of h1, h1≥1200um, and the edge decobaltized layer has a depth of h2, h2≤2h1.

25. The polycrystalline diamond compact according to claim 24, characterized in that: The inclination angle of the boundary surface between the non-decobalted layer and the decobalted layer is a, and a<45°.

26. The polycrystalline diamond compact according to claim 25, characterized in that: The cross-sections of the substrate, the non-decobalted layer and the decobalted layer are any one of a circle, a sector, a regular polygon and an irregular polygon.

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