PDC cutting tooth and preparation method thereof

Abstract

The invention discloses a superhard material composite sheet and a method for manufacturing the superhard material composite sheet. A superhard material compact may include a diamond body and a metal substrate. The diamond body comprises a first phase comprising a binder-free intergranular diamond-diamond combination covering up to the entire diamond body; and a second phase including a binder / catalyst within interstitial regions of the intergranular bonded diamond body. The first phase is substantially free of binder / catalyst material. The metal substrate is in direct contact with the diamond body. The diamond body includes a first region comprising a catalyst / binder material and a second region substantially free of binder / catalyst. The second region may be located on a wear resistant surface of the superhard material clad sheet.

Description

[0001] Priority Declaration

[0002] This application claims the benefit of the following nonprovisional applications, each of which is incorporated herein by reference in its entirety:

[0003] U.S. application number: 18 / 535,587; Application date: December 11, 2023; Invention name: PDC cutting teeth and preparation methods thereof. Technical Field

[0004] The present invention relates to a superhard material and a method for manufacturing the superhard material, and more particularly to a polycrystalline diamond compact (PCD) for manufacturing PDC cutting teeth using binderless diamond. Background Art

[0005] Polycrystalline diamond (PCD) materials and PDC elements formed therefrom are well known in the art. Conventional PDCs are formed by combining diamond particles with a suitable binder / catalyst material. The mixture is subjected to extremely high temperature / high pressure (HPHT) conditions, where the binder / catalyst material promotes the desired intercrystalline diamond-diamond bonding between the particles, thereby forming a polycrystalline diamond structure. The resulting PDC structure can improve wear resistance and hardness, making PDC materials very useful in high-strength wear and cutting applications where high wear resistance and hardness are required. Binder / catalyst materials typically used to form PDCs include Group VIII elements, most commonly cobalt (Co). Conventional PDCs consist of 85%-95% (volume fraction) diamond and the remainder binder / catalyst material. The binder / catalyst material is present in the PDC material in the gaps between the diamond particles that are bonded together.

[0006] One problem with this conventional PDC material is thermal degradation due to the difference in thermal expansion between the cobalt binder / catalyst material in the interstitial space and the intergranularly bonded diamond. This is known to occur at temperatures around 400°C. When the expansion is sufficient, the diamond-to-diamond bond can break, resulting in cracks and chips.

[0007] Another issue with conventional PDC materials is the presence of a binder / catalyst material attached to the interstitial regions of the diamond crystals, causing another form of thermal degradation. The presence of the binder / catalyst material is known to catalyze the phase transition of diamond (to carbon monoxide, carbon dioxide, or graphite) as temperature rises, thus limiting the practical operating temperature of PDC materials to around 750°C.

[0008] Attempts to address this problem are known in the art. Generally, these attempts involve forming PDC materials that have greater thermal stability than the conventional PDC materials discussed above. One known technique for producing thermally stable PDC materials involves a multi-step process that first forms a conventional sintered PDC element by combining diamond particles and a cobalt binder / catalyst material under high temperature and pressure, and then selectively removes the binder / catalyst material from the working surface of the sintered element.

[0009] While this multi-step process can remove binder / catalyst from selected portions of the working surface of a PDC element and can improve the thermal stability of the element areas from which the binder / catalyst was removed, it involves a multi-step process that is both time-consuming and labor-intensive.

[0010] Therefore, there is a need to develop a PDC material with improved thermal stability compared to conventional PDC materials. Summary of the Invention

[0011] In one embodiment, a superabrasive compact may include a diamond body and a metallic substrate, wherein the diamond body includes a first phase, the first phase including a binderless intercrystalline diamond-to-diamond bonded matrix covering the entire diamond body;

[0012] and a second phase comprising a binder / catalyst within interstitial regions of the intergranularly bonded diamond body. The first phase is substantially free of binder / catalyst material. The metal substrate is in direct contact with the diamond body. The diamond body includes a first region comprising the catalyst / binder material and a second region substantially free of the binder / catalyst. The second region may be located on a wear-resistant surface of the superhard material compact.

[0013] In any embodiment, optionally, the binder / catalyst material comprises cobalt.

[0014] In any embodiment, optionally, the second region is substantially non-porous.

[0015] In any embodiment, optionally, the metal substrate comprises a metal carbide.

[0016] In any embodiment, optionally, the second region is substantially free of metal.

[0017] In any embodiment, optionally, the metal comprises a catalyst.

[0018] In any embodiment, optionally, the catalyst comprises cobalt.

[0019] In any embodiment, optionally, the metal carbide comprises tungsten carbide.

[0020] In any embodiment, optionally, the second region of the diamond body has a thickness to a depth of at least about 0.1 mm from the wear resistant surface.

[0021] In any embodiment, optionally, the first region of the diamond body has an average thickness greater than about 0.15 mm.

[0022] In any embodiment, optionally, the content of catalyst / binder material in a first region of the diamond body increases with increasing distance from a second region.

[0023] In another embodiment, a superhard material compact may include a diamond body. The diamond body may include a first region and a second region. The first region may include a catalyst / binder material, and the second region may be substantially free of the binder / catalyst. The second region may be located on a wear-resistant surface of the superhard material compact. The second region may include binderless polycrystalline diamond material. The second region may be substantially free of pores.

[0024] In any embodiment, the diamond body may optionally include a first phase and a second phase. The first phase may include a binderless intercrystalline diamond-diamond bond covering the entire diamond body. The second phase may include a binder / catalyst within interstitial regions of the intercrystalline bonded diamond body.

[0025] In another embodiment, a superhard material composite may include a diamond body and a metal substrate. The diamond body includes a first phase and a second phase. The first phase may include a binderless intergranular diamond-diamond bond covering the entire diamond body. The second phase may include a binder / catalyst within the interstitial regions of the intergranular bonded diamond body. The metal substrate is in direct contact with the diamond body. The diamond body includes a first region and a second region. The second region is located on a wear-resistant surface of the superhard material composite. The second region is substantially free of pores and forms a substantially binderless intergranular diamond-diamond bond on the wear-resistant surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above summary of the invention and the following detailed description of the embodiments will be better understood when read in conjunction with the accompanying drawings.It should be understood that the illustrated embodiments are not limited to the precise arrangements and instrumentalities shown in the drawings.

[0027] Figure 1 is a schematic diagram of a polycrystalline diamond compact produced in an ultra-high pressure, high temperature (HPHT) process according to one embodiment.

[0028] Figure 2is a schematic perspective view of a cylindrical thermally stable polycrystalline diamond compact produced in an ultra-high pressure, high temperature (HPHT) process according to another embodiment.

[0029] Figure 3 is a schematic diagram of an assembly cup loaded with a carbide substrate and multiple diamonds according to one embodiment.

[0030] Figure 4 is a schematic diagram of an assembly cup loaded with a carbide substrate and a plurality of diamonds (or solid binderless diamonds) according to one embodiment. DETAILED DESCRIPTION

[0031] Before describing the embodiments, the terms, methods, systems and materials are first explained; it should be understood that the present disclosure is not limited to the specific terms, methods, systems and materials described, as these may vary. It should also be understood that the terms used in the specification are only used to describe specific examples of the embodiments and are not intended to limit the scope of the embodiments. For example, the singular forms "a, an" and "the" used herein also include plural forms unless the context clearly dictates otherwise. In addition, the word "including" used herein is intended to mean "including but not limited to". Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art.

[0032] Unless otherwise indicated, all references to ingredient amounts, properties (e.g., dimensions, weights, reaction conditions, etc.) used in this specification and claims should be understood as being modified in all cases by the term "about." Therefore, unless otherwise indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that may vary depending on the desired properties to be obtained according to the present invention. At a minimum, and not as a limitation on the scope of the application of the doctrine of equivalents to the claims, each numerical parameter should at least be interpreted based on the number of reported significant figures and by applying ordinary rounding.

[0033] As used herein, the term "about" refers to plus or minus 10% of the numerical value of the number with which it is used. Thus, about 50% means within the range of 45%-55%.

[0034] As used herein, the term "superhard material particles" may refer to superhard particles or superhard material particles having a Knoop hardness of 3500 KHN or greater. For example, the superhard material particles may include diamond and cubic boron nitride.

[0035] As used herein, the term "abrasive material" refers to any material used to abrade away softer materials.

[0036] As used herein, the term "particle" refers to one or more discrete bodies. A particle is also considered a crystal or grain.

[0037] As used herein, the term "superhard material compact" refers to a sintered product made from superhard material particles, such as diamond feedstock or cubic boron nitride particles. The compact may or may not include a support, such as a tungsten carbide support. The term "superhard material compact" is a broad term that can include cutting elements, tools, or polycrystalline cubic boron nitride inserts.

[0038] As used herein, the term "cutting element" means and includes any element of an earth-boring tool that is used to cut or otherwise fragment earth formation material when the earth-boring tool is used to form or enlarge a borehole in the earth formation.

[0039] As used herein, the term "non-catalytic binder" material may refer to any material that does not participate in or contribute to the chemical formation of the tungsten carbide substrate, including metallic elements, non-metallic, or semiconductor materials.

[0040] As used herein, the term "feedstock" or "diamond feedstock" refers to any type of diamond particles or diamond powder used as a starting material for further synthesis of a PDC compact.

[0041] As used herein, the term "polycrystalline diamond" refers to a plurality of randomly oriented or highly oriented single crystal diamond particles, which may refer to a whole or a particle composed of a large number of small single crystal diamond particles of any size. Polycrystalline diamond particles generally have no cleavage planes.

[0042] As used herein, the term "superhard material" refers to an abrasive material having excellent hardness and wear resistance. Diamond and cubic boron nitride are examples of superhard materials, with Knoop indentation hardness values ​​exceeding 3500.

[0043] As used herein, the terms "diamond particles" or "particles" or "diamond powder" are a plurality of single crystal or polycrystalline diamond particles and are used interchangeably in this application and have the same meaning as "particles" defined above.

[0044] A polycrystalline diamond compact (hereinafter referred to as "PCD") may refer to a volume of crystalline diamond particles having embedded foreign matter filling the inter-particle spaces. In a particular case, the superhard material compact comprises crystalline diamond grains that are strongly bonded by diamond-diamond bonding to form a rigid polycrystalline diamond body, and an intergranular region between the bonded grains, a portion of which is filled with a catalyst material (e.g., cobalt or an alloy thereof) that is used to promote diamond bonding during the manufacturing process, while another portion may be filled with other materials that remain after the diamond compact is sintered. Suitable metal solvent catalysts may include iron-group transition metals from Group VIII of the Periodic Table of Elements.

[0045] As used herein, "thermally stable polycrystalline diamond" is understood to mean intercrystalline bonded diamond that includes a volume or region that is substantially free of the solvent metal catalyst or binder used to form PCD, or where the solvent metal catalyst or binder used to form PDC remains within a region of the diamond body but, as described above, reacts at elevated temperatures or otherwise loses its ability to adversely affect bonding to the diamond.

[0046] Polycrystalline diamond compacts (or PDC compacts) can be manufactured in various ways, and the examples discussed herein do not limit the various types of diamond composites and PDC compacts that can be produced according to embodiments.

[0047] Compared to conventional PDC materials, the PDC materials of the present invention and the PDC compacts formed therefrom are specially designed to provide improved thermal stability and are therefore referred to as thermally stable PCD.

[0048] The thermally stable PDC material disclosed herein can be formed through a single process step of consolidating and sintering the PDC material. In this single ultrahigh-pressure, high-temperature (UHPHT) processing step, the diamond particles are sintered without the use of a binder / catalyst material to promote diamond-to-diamond intercrystalline bonding, forming a binderless polycrystalline diamond compact. This compact exhibits greater thermal stability than that achieved with a binder / catalyst material, thereby contributing to the formation of PDC elements, such as compacts, with improved overall thermal stability compared to conventional PCD.

[0049] like Figure 1 As shown, the superhard material composite sheet 10 of the present invention has a material microstructure comprising at least two material phases. A first phase 12 comprises a binderless intercrystalline diamond-diamond bond covering the entire diamond body, and a second phase 14 is located in the interstitial spaces between the diamonds and comprises a binder / catalyst within the interstitial regions of the intercrystalline bonded diamond bodies. In one embodiment, the binder / catalyst material may include cobalt. In one embodiment, the first phase is substantially free of binder / catalyst material.

[0050] Figure 2 A superhard material compact 10 is shown consistent with an embodiment. The superhard material compact 10 may be inserted into a downhole portion of a suitable tool, such as a drill bit. One example of a superhard material compact 10 may include a diamond table 25 having a top surface 21 .

[0051] In one embodiment, the superhard material compact 10 may be a stand-alone compact without a substrate. In another embodiment, the superhard material compact 10 may include a metal substrate 20 attached to a superhard material diamond body 25 formed of a plurality of polycrystalline diamond particles.

[0052] The metal substrate 20 may be a metal carbide attached to the superhard material diamond body 25 via an interface 22 separating the superhard abrasive diamond table 25 and the metal base substrate 20. For example, the metal carbide may comprise tungsten carbide. The interface 22 may have an uneven interface. The substrate for forming the PDC composite of the present invention may be selected from conventional materials of the same type used to form conventional PDC material substrates, including carbides, nitrides, carbonitrides, cermets, and mixtures thereof. In one exemplary embodiment, the substrate may be formed of cemented tungsten carbide (WC-Co).

[0053] The metal substrate 20 may be made of a hard metal carbide and a binder in which carbon is at least partially dissolved. In one embodiment, the metal substrate 20 may be a cemented carbide cobalt tungsten carbide, and the superhard material diamond body 25 may be formed of a polycrystalline superhard material, such as polycrystalline diamond or diamond polycrystalline particles bonded by itself or by a foreign material.

[0054] Still Figure 2 As shown, the superhard material diamond body 25 may include at least two regions, namely a first region 24 and a second region 26. The first region 24 may be closer to the interface 22 and may be sandwiched between the metal substrate 20 and the second region 26.

[0055] In one embodiment, the first region 24 may include a catalyst / binder material. The second region 26 may be substantially free of a binder / catalyst and may be located on the wear resistant or top surface 21 of the superhard material compact 10 .

[0056] The second region 26 may be a binderless polycrystalline diamond material. The binderless polycrystalline diamond material may ultimately contain a plurality of diamond grains, the average grain size of which may be, for example, greater than about 1 micron. In one embodiment, the second region of the diamond body has a thickness (D) of at least about 0.1 mm from the wear-resistant surface.

[0057] In one embodiment, the first region of the diamond body has an average thickness greater than about 0.15 mm.

[0058] Due to HPHT or UHPHT, the catalyst / binder cobalt may diffuse from the metal substrate into the diamond body, which may result in the content of catalyst / binder material in a first region of the diamond body increasing with increasing distance from a second region.

[0059] When polycrystalline diamond is used to form the superhard material diamond body 25, the superhard material compact 10 may be referred to as a polycrystalline diamond compact ("PCD"). PDC compacts are known for their toughness and durability, which make them an effective cutting tooth in demanding applications. Although one type of superhard material compact 10 has been described, other types of superhard material compacts 10 may also be used. For example, in one embodiment, the superhard material compact 10 may have a chamfer (not shown) around the periphery of the top surface 21. The chamfer may have a vertical height of, for example, about 0.5 mm or 1 mm, and an angle of, for example, about 45°, which may provide a particularly strong and fracture-resistant tool assembly.

[0060] like Figure 3 In the pre-sintered cup assembly 30 shown, a metal cup 38 (e.g., Ta or Nb) can be used to load a first portion 36 of modified diamond particles containing carbon, graphite, or no catalytic material. A high-frequency vibrator can be used to level the portion 36. The second portion 34 containing diamond particles can then be carefully loaded on top of the first portion 36. A high-frequency vibrator is again used to level the second portion 34 as a diamond bed. This portion can be just pure diamond raw material. A cemented carbide tungsten carbide substrate 32 is inserted into the cup 38. Its interface is in direct contact with the diamond bed. Subsequently, a load of, for example, 100 kg is applied to the loaded material to densify it. The loading cup is further assembled using an HPHT synthetic block assembly and subjected to an ultra-high pressure, high temperature sintering process in a six-sided top press at 16 GPa and 2300°C. The sintered part is further ground and processed into Figure 2 The final dimensions of the PDC product are shown in . Suitable binder / catalyst materials for forming the thermally stable PDC material of the present invention include metals selected from Group VIII of the Periodic Table of Elements, with a particularly preferred binder / catalyst material being cobalt.

[0061] Optionally, the second portion 34 can be mixed with a catalytic material such as cobalt, iron, or nickel alloy at a concentration of approximately 0.1% to 20% by weight into a PDC material. The PDC material is prepared by mixing synthetic diamond powder having an average particle size ranging from submicron to 100 microns, more preferably from about 20 to 80 microns, with or without cobalt powder to form a cobalt coating on the diamond surface. The diamond powder can comprise grains having a unimodal or multimodal particle size distribution. In one exemplary embodiment, the cobalt powder has an average grain size ranging from approximately submicron to tens of microns, more preferably from about 0.1 to about 10 microns.

[0062] Another method for forming a cobalt coating on the surface of diamond grains is to apply a thin layer of cobalt to the surface of the diamond grains by methods known in the art. This can be accomplished using a variety of methods, such as sputter coating, physical vapor deposition, chemical vapor deposition, decomposition of organometallic complexes, electrolytic plating, and the like. It will be appreciated that methods not specifically listed may also be used to form a coating on the diamond grains.

[0063] In one exemplary embodiment, a mixture of diamond and cobalt powder comprises 80% to 99% diamond by volume, with the remainder being cobalt. The diamond grains and cobalt powder are mixed together using conventional processes such as ball milling or stirred milling, with the milling time being adjusted to achieve optimal coverage of the cobalt powder on the diamond grain surfaces. It should be understood that during this process step, some diamond grains may not be fully coated with the binder / catalyst material.

[0064] Alternatively, Figure 3 As shown in the figure, a metal cup 38 (Ta or Nb) can be used to load a first part 36 containing modified diamond particles containing carbon, graphite or no catalytic material. A high-frequency vibrator is used to level this part. Then, a second part 34 containing diamond particles can be loaded on top of the first part 36. Similarly, a high-frequency vibrator can be used to level the second part 34 as a diamond bed. The part 34 is premixed with 0.1wt.%-20wt.% of non-catalytic materials such as B, Be, Al, Mo, Nb, Ta, V, Zr, Si, Ti, CaCO3 and MgCO3 powder. A cemented carbide tungsten carbide substrate 32 is inserted into the cup. Its interface is in direct contact with the diamond bed. Subsequently, a load of 100kg is applied to the loaded material to densify it. The loading cup is further assembled using an HPHT synthesis block assembly and subjected to an HPHT sintering process in a six-sided top press at 16GPa and 2300°C. The sintered part is further ground and processed into Figure 2 Final dimensions of the PDC product shown.

[0065] A non-catalytic material or getter material is mixed with the diamond grains and the mixture is mixed together by conventional methods such as ball milling or stirred milling until the getter material is able to fully coat or bond with the diamond. Suitable getter materials for forming the thermally stable PDC materials of the present invention include those that are capable of reacting with the binder / catalyst material during the consolidation and sintering process, for example, at the stage in the consolidation and sintering process where intercrystalline diamond bonds begin to form. Suitable getter materials include those that react with the binder / catalyst material to form a compound that has a higher thermal stability than the single binder / catalyst material, thereby contributing to the overall thermal stability of the PDC material. In forming the thermally stable PDC materials of the present invention, a single getter or a combination of multiple getters may be used.

[0066] In one exemplary embodiment, when the binder / catalyst is cobalt, the desired getter material comprises silicon or a silicon-containing compound provided in powder form. Preferred silicon or silicon-containing compounds include pure silicon (Si) and silicon carbide (SiC). These getter materials can be used alone or in combination. More preferably, a combination of silicon and silicon carbide is used. When mixed with cobalt-coated diamond grains, the resulting mixture comprises a continuous coating of the binder / catalyst material and the getter material.

[0067] The resulting mixture is cleaned by high-temperature treatment in a vacuum or reducing atmosphere to improve the powder's sinterability. The mixed powder mixture is placed in a desired container and placed in a suitable high-pressure, high-temperature consolidation and sintering apparatus. The apparatus is then activated to subject the container to the desired high-pressure, high-temperature conditions for consolidation and sintering. The thermally stable PDC material of the present invention can be cured and sintered using conventional PDC curing and sintering equipment and techniques.

[0068] Theoretically, during the high-pressure, high-temperature consolidation and sintering process, the cobalt coating on the diamond grains provides highly localized catalysis for the rapid formation of strong bonds between the diamond grains or crystals, creating intergranularly bonded diamond. As these bonds form, the cobalt moves into the interstitial regions between the intergranularly bonded diamonds, where it combines with and reacts with the getter material (in this case, Si and / or SiC). The following reaction is believed to occur to form cobalt disilicide (CoSi2):

[0069] Co + 2Si → CoSi2 Reaction I

[0070] Co + 2SiC → CoSi2 + 2C Reaction II

[0071] The formation of cobalt disilicide according to the above reaction is a desirable outcome, as it is known to have superior thermal stability to elemental cobalt, thereby enhancing the overall thermal stability of the PDC material. If the getter material used is SiC, the following reaction suggests that the free carbon produced in Reaction II will precipitate as diamond, as this reaction occurs during a high-pressure / high-temperature reaction within the diamond stability region of the diamond phase diagram.

[0072] The formation and presence of this precipitated diamond within the binder phase of the PDC material's microstructure is believed to have two advantages. First, it can improve the overall wear resistance of the PDC material. Second, it increases the thermal conductivity of the binder phase while also providing a thermal expansion coefficient that matches that of the intergranular diamond binder phase, thereby contributing to the overall thermal stability of the material.

[0073] An advantage of using pure silicon (Si) as the getter material is that excess material that has not reacted with cobalt, such as silicon, is believed to form a reactive phase with the diamond crystals in the intercrystalline diamond bond phase according to the following reaction:

[0074] Si+C→SiC Reaction III

[0075] The reaction, involving pure silicon and diamond crystals, is designed to enhance the bond between the binder phase and the intergranular diamond phase, thereby providing a PDC material with greater overall structural strength.

[0076] It should be understood that, in addition to the specific application of the PDC composite sheet or element formed from the PDC material, the type and amount of getter material used can and will vary depending on the specific type and amount of binder / catalyst material used. Furthermore, as described above, the amount of getter material used (e.g., an amount in excess of the stoichiometric ratio) may vary depending on the type of reaction product being formed. For example, as described above, it may be desirable to use a stoichiometric excess of a particular getter material to produce a desired reaction product at the binder or getter material stage of the material structure in addition to producing a desired reaction product having improved thermal stability. In one exemplary embodiment, a stoichiometric excess level of up to about 50% may be desired, with a more preferred stoichiometric excess range of about 10%-20%.

[0077] It can be expected that the molar volume change caused during the reaction may have an important impact on the final product. Since the target reaction occurs in the pores between the diamond grains, the reaction that promotes the increase in overall molar volume may not continue to completion because the volume between the diamond grains is greatly limited by the pressure applied by the HPHT or UHPHT device. On the contrary, if the reaction molar volume is greatly reduced and the reaction volume is insufficient to fill the initial pores, microstructural problems such as microcracks in the reaction material may result. Obviously, by engineering the combination of reactants (i.e., Si and SiC), the molar volume change can be adjusted over a wide range to help solve potential microstructure-related problems. Table 1 below lists the reactant and product molar volume data per mole of cobalt in the above reactions I and II.

[0078] Table 1

[0079]

[0080] In one exemplary embodiment, the type and amount of getter material are carefully selected to ensure that, during the consolidation and sintering process, the PDC material is formed, achieving the desired level of improved thermal stability while also not adversely affecting the sintered product, such as by reducing sintering defects such as microcracks. Ideally, the type and amount of getter material used in preparing the PDC material of the present invention should achieve an optimal combination of physical properties and good manufacturability in the PDC composite.

[0081] Although the superhard material composite sheet 10 has a specific structure, it should be understood that the PDC composite sheet of the present invention can be designed into various shapes and sizes according to specific wear resistance and / or cutting application requirements.

[0082] In addition, it should be understood that the PDC composite sheet of the present invention includes a PDC body that is formed in whole or in part from the PDC material of the present invention. Figure 2 In the exemplary embodiment shown, the PDC compact comprises a PDC body made entirely of the PDC material of the present invention, i.e., including the reaction product of a binder / catalyst and a getter material distributed throughout the material. Alternatively, Figure 2 An embodiment of a PDC compact of the present invention 10 is shown in which only a portion of the PDC body 10 is formed from the PDC material of the present invention. In such an embodiment, the PDC body 10 includes a first region 24 comprising the PDC material of the present invention, and a second region 26 adjacent to the first region but not comprising the PDC material of the present invention. The second region 26 can be located near the working surface of the PDC compact to take advantage of its improved thermal stability. The first region can comprise any type of conventional PDC material or a material that does not contain PDC.

[0083] In addition to the specific silicon getter materials discussed above, the PDC materials of the present invention can also be prepared by using materials or elements other than silicon or silicon-containing compounds that can react with the binder / catalyst material and form compounds that are more thermally stable than the binder / catalyst itself. It is desirable that the elements used for this purpose meet the following requirements.

[0084] (a) They must form thermally stable compounds with the binder / catalyst over a wide stoichiometric range;

[0085] (b) The reaction between the binder / catalyst and the getter element should preferably be carried out in the liquid phase so that the reaction can proceed within a reasonable time, or the solid-state diffusion of the binder / catalyst into these elements must be rapid (and vice versa). Thus, the binary compound formed should have a eutectic melting temperature reasonably close to the typical processing temperature of the PDC;

[0086] (c) At the typical reaction temperature and pressure of PDC, the element has no strong solvent-catalyst effect on diamond, but must also act as a strong carbide-forming element so that the material that has not reacted with the binder / catalyst combines with part of the diamond, thereby forming a stable carbide phase in the matrix.

[0087] As shown in Table 2 below, based on the principles of the present invention, other getter materials suitable for preparing the PDC material of the present invention include:

[0088] Table 2

[0089]

[0090] In another embodiment, Figure 3 As shown, a pre-sintered tungsten carbide green body 32 can be inserted into the cup 38 instead of cemented tungsten carbide. Further in another embodiment, a solid binderless polycrystalline diamond disk 36 of near full density can be used instead of diamond feedstock or powder. In yet another embodiment, instead of loading two separate diamond layers, a first part (comprising carbon, graphite or modified diamond particles without catalytic material) is loaded into the cup 38 and cemented tungsten carbide 32 is loaded on top of the first part. A load of 100 kg is applied to densify the loaded material. The loaded cup is further assembled using an HPHT composite block assembly and subjected to an HPHT sintering process in a six-sided top press at 16 GPa and 2300°C. The sintered part is further ground and processed to the final size of the PDC product, such as Figure 2 The polycrystalline diamond layer 34 is formed by direct contact of carbon with a catalyst / binder diffused from cemented tungsten carbide.

[0091] like Figure 4 As shown, a metal cup 48 (e.g., Ta or Nb) is loaded with a first portion of a flat solid binderless polycrystalline diamond disk 46 at near full density. Subsequently, a second portion of a fully leached flat diamond disk 44 is loaded on top of the first portion 46. A flat hard tungsten carbide substrate 42 is inserted into the cup 48. Its planar interface directly contacts the fully leached diamond disk. The loading cup 40 is further assembled using an HPHT composite block assembly and HPHT sintered in a six-sided top press at greater than 5.5 GPa and 1500°C. The sintered part is further ground and processed into Figure 2 Final dimensions of the PDC product shown.

[0092] Alternatively, Figure 4 As shown, an unleached PDC diamond table 44 is loaded into the cup 48 in place of the leached PDC diamond table, with its planar diamond surface directly contacting the first portion 46 .

[0093] If the thermally stable PDC composite sheet of the present invention includes a substrate formed of cemented tungsten carbide, a barrier layer may be required between the substrate and the PDC material to prevent excess cobalt from penetrating therethrough, which could adversely affect the thermal stability of the resulting PDC material. This barrier layer can be located between the substrate and the PDC material, or it can be located within the PDC material, maintaining a desired distance from the substrate. Materials useful for forming this barrier layer include refractory metals that readily form carbides, such as Zr, Nb, Mo, and Ta, as well as precious metals such as Ru, Re, Rh, and Pt.

[0094] The first embodiment of the above-mentioned PDC material will be better understood through the following examples:

[0095] Example 1

[0096] The PDC cutting teeth are produced by the method described in the prior art and are composed of a starting diamond powder having a particle size of about 1-10 microns and a diamond powder having a particle size of about 10 nanometers to about 5 microns, and a metal carbide (e.g., tungsten carbide) attached to the polycrystalline diamond through the interface between the polycrystalline diamond and the tungsten carbide.

[0097] A certain volume of diamond feedstock is loaded into the Ta cup, which is then inserted into a WC substrate (0.711” outer diameter). The WC substrate is pre-sintered with cobalt. The assembled Ta cup is further coated with salt and graphite sleeves and some graphite sheets. The Ta cup is tightly mounted in the sleeve. The assembled component is transferred to the composite block loading area, and the entire body is loaded into a composite block specially designed for the six-sided top press. The composite block is then loaded into the space formed by the anvil of the six-sided top press, and the composite block is subjected to an ultra-high pressure and high temperature (UHPHT) cycle for 30 minutes. The holding pressure is maintained at around 15.0 GPa and the holding temperature is maintained at around 1550°C. The holding time for the thermally stable component to bond with the carbide is about 10 minutes. After the bonding cycle is completed, the cup is removed from the pressed composite block for further post-processing.

[0098] The cutting teeth are ground and processed to a diameter of 16mm and a height of 13.2mm. A 45-degree chamfer is placed on the edge of the diamond, and the thickness is about 0.4mm.

[0099] Although reference has been made to specific embodiments, it is apparent that those skilled in the art may design other embodiments and variations without departing from the spirit and scope of the invention. The appended claims are intended to be interpreted as including all such embodiments and equivalent technical solutions.

Claims

1. A superhard material composite sheet comprising: A diamond body, comprising: A first phase comprising a binderless intercrystalline diamond-diamond compact covering the entire diamond body; a second phase comprising a binder / catalyst within interstitial regions of the intercrystalline bonded diamond bodies; wherein the first phase is substantially free of the binder / catalyst material; A metal substrate is in direct contact with the diamond body, wherein the diamond body includes a first region containing the catalyst / binder material and a second region substantially free of the binder / catalyst, and the second region is located on the wear-resistant surface of the superhard material composite sheet.

2. The superhard material composite sheet according to claim 1, wherein: The binder / catalyst material includes cobalt.

3. The superhard material composite sheet according to claim 1 or 2, wherein: The second region is substantially free of pores.

4. The superhard material composite sheet according to any one of claims 1 to 3, wherein: The metal substrate includes metal carbide.

5. The superhard material composite sheet according to any one of claims 1 to 4, wherein: The metal carbide includes tungsten carbide.

6. The superhard material composite sheet according to any one of claims 1 to 5, wherein: The second region is substantially free of metal.

7. The superhard material composite sheet according to any one of claims 1 to 6, wherein: The metal comprises a catalyst.

8. The superhard material composite sheet according to any one of claims 1 to 7, wherein: The catalyst includes cobalt.

9. The superhard material composite sheet according to any one of claims 1 to 8, wherein: The content of catalyst / binder material in a first region of the diamond body increases with increasing distance from a second region.

10. A superhard material composite sheet comprising: A diamond body comprising: First Area; A second region, wherein the first region includes a catalyst / binder material, the second region is substantially free of binder, and the second region is located on a wear-resistant surface of the superhard material composite sheet; wherein the second region includes a binder-free polycrystalline diamond material, and the second region is substantially free of pores.

11. The superhard material composite sheet according to claim 10, wherein: The second region is substantially free of metal.

12. The superhard material composite sheet according to any one of claims 10 to 11, wherein: The metal comprises a catalyst.

13. The superhard material composite sheet according to any one of claims 10 to 12, wherein: The catalyst includes cobalt.

14. The superhard material composite sheet according to any one of claims 10 to 13, wherein: The content of catalyst / binder material in a first region of the diamond body increases with increasing distance from a second region.

15. The superhard material composite sheet according to any one of claims 10 to 14, wherein: The diamond body comprises: a first phase comprising a binderless intergranularly bonded diamond body covering the entire diamond body; The second phase comprises a binder / catalyst within the interstitial regions of the intercrystalline bonded diamond bodies.

16. A superhard material composite sheet comprising: A diamond body, comprising: A first phase comprising a binderless intergranular diamond-diamond compact covering the entire diamond body; a second phase comprising a binder within the interstitial regions of the intercrystalline bonded diamond bodies; A metal substrate is in direct contact with the diamond body, wherein the diamond body includes a first region and a second region, the second region is located on the wear-resistant surface of the superhard material composite sheet, the second region is substantially free of pores, and forms an intergranular diamond-diamond bond substantially free of binder on the wear-resistant surface.

17. The superhard material composite sheet according to claim 16, wherein: The metal substrate includes carbide.

18. The superhard material composite sheet according to any one of claims 16 to 17, wherein: The carbide includes tungsten carbide.

19. The superhard material composite sheet according to any one of claims 16 to 18, wherein: The content of the binder material in the first region of the diamond body increases with increasing distance from the second region.

20. The superhard material composite sheet according to any one of claims 16 to 19, wherein: The second region includes a plurality of substantially metal-free diamonds.

Images