Patent Grant
10226854
Wear-resistant, polycrystalline diamond compacts (“PDCs”) are utilized in a variety of mechanical applications. For example, PDCs are used in drilling tools (e.g., cutting elements, gage trimmers, etc.), machining equipment, bearing apparatuses, wire-drawing machinery, and in other mechanical apparatuses.
PDCs have found particular utility as superabrasive cutting elements in rotary drill bits, such as roller-cone drill bits and fixed-cutter drill bits. A PDC cutting element typically includes a superabrasive diamond layer commonly known as a diamond table. The diamond table is formed and bonded to a substrate (e.g. a cemented carbide) using a high-pressure/high-temperature (“HPHT”) process. The PDC cutting element may be brazed directly into a preformed pocket, socket, or other receptacle formed in a bit body. The substrate may often be brazed or otherwise joined to an attachment member, such as a cylindrical backing. A rotary drill bit typically includes a number of PDC cutting elements connected to the bit body. It is also known that a stud carrying the PDC may be used as a PDC cutting element when mounted to a bit body of a rotary drill bit by press-fitting, brazing, or otherwise securing the stud into a receptacle formed in the bit body.
Conventional PDCs are normally fabricated by placing a substrate into a container with a volume of diamond particles positioned on a surface of the substrate. A number of such containers may be loaded into an HPHT press. The substrate(s) and volume(s) of diamond particles are then processed under HPHT conditions in the presence of a catalyst material that causes the diamond particles to bond to one another to form a matrix of bonded diamond grains defining a polycrystalline diamond (“PCD”) table. The catalyst material is often a metal-solvent catalyst (e.g., cobalt, nickel, iron, or alloys thereof) that is used for promoting intergrowth of the diamond particles.
In one conventional approach, a constituent of the cemented-carbide substrate, such as cobalt from a cobalt-cemented tungsten carbide substrate, liquefies and sweeps from a region adjacent to the volume of diamond particles into interstitial regions between the diamond particles during the HPHT process. The cobalt acts as a catalyst to promote intergrowth between the diamond particles, which results in formation of a matrix of bonded diamond grains having diamond-to-diamond bonding therebetween, with interstitial regions between the bonded diamond grains being occupied by the solvent catalyst.
Despite the availability of a number of different PDCs, manufacturers and users of PDCs continue to seek PDCs that exhibit improved toughness, wear resistance, thermal stability, or combinations of the foregoing.
Embodiments of the invention relate to PDCs including a PCD table exhibiting an at least bi-layer PCD structure that enhances the leachability thereof, drill bits using such PDCs, and methods of manufacture. In an embodiment, a PDC includes a substrate and a PCD table bonded to the substrate. The PCD table includes an upper surface. The PCD table further includes a first PCD region comprising bonded-together diamond grains. The first PCD region exhibits a first diamond density. At least a portion of the first PCD region that extends inwardly from the upper surface is substantially free of metal-solvent catalyst. The PCD table further includes an intermediate second PCD region bonded to the substrate, which is disposed between the first PCD region and the substrate. The intermediate second PCD region includes bonded-together diamond grains defining interstitial regions, with at least a portion of the interstitial regions including metal-solvent catalyst disposed therein. The intermediate second PCD region exhibits a second diamond density that is greater than that of the first diamond density of the first PCD region.
In an embodiment, a method of fabricating a PDC includes forming an assembly including a first region including diamond particles, a substrate, an intermediate second region disposed between the substrate and the first region. The intermediate second region includes a mixture including diamond particles and one or more sp2-carbon-containing additives. The method further includes subjecting the assembly to an HPHT process to sinter the diamond particles of the first region and the intermediate second region in the presence of a metal-solvent catalyst so that a PCD table is formed that bonds to the substrate. The PCD table includes a first PCD region formed at least partially from the first region and the metal-solvent catalyst, and a second PCD region disposed between the first PCD region and the substrate. The second PCD region is formed at least partially from the second intermediate region and the metal-solvent catalyst. The method additionally includes leaching the metal-solvent catalyst from at least a portion of the first PCD region to form an at least partially leached region.
Other embodiments include applications utilizing the disclosed PDCs in various articles and apparatuses, such as rotary drill bits, bearing apparatuses, wire-drawing dies, machining equipment, and other articles and apparatuses.
Features from any of the disclosed embodiments may be used in combination with one another, without limitation. In addition, other features and advantages of the present disclosure will become apparent to those of ordinary skill in the art through consideration of the following detailed description and the accompanying drawings.
The drawings illustrate several embodiments of the invention, wherein identical reference numerals refer to identical elements or features in different views or embodiments shown in the drawings.
Embodiments of the invention relate to PDCs including a PCD table exhibiting an at least bi-layer PCD structure that enhances the leachability thereof, drill bits using such PDCs, and methods of manufacture. The disclosed PDCs may also be used in a variety of other applications, such as, machining equipment, bearing apparatuses, and other articles and apparatuses.
The PCD table 102 includes a plurality of directly bonded-together diamond grains exhibiting diamond-to-diamond bonding (e.g., sp3 bonding) therebetween. As will be discussed in more detail below, the PCD table 102 may be formed on the substrate 104 (i.e., integrally formed with the substrate 104) by HPHT sintering diamond particles on the substrate 104. The plurality of directly bonded-together diamond grains define a plurality of interstitial regions. The PCD table 102 defines an upper surface 108 and peripheral surface 110. In the illustrated embodiment, the upper surface 108 includes a substantially planar major surface 112 and a peripherally-extending chamfer 114 that extends between the peripheral surface 110 and the major surface 112. The upper surface 108 and/or the peripheral surface 110 may function as a working surface that contacts a formation during drilling operations.
Referring specifically to
The first PCD region 116 has been treated leached to deplete the metal-solvent catalyst therefrom that used to occupy the interstitial regions between the bonded diamond grains of the first PCD region 116. The leaching may be performed in a suitable acid (e.g., aqua regia, nitric acid, hydrofluoric acid, or combinations thereof) so that the first PCD region 116 is substantially free of the metal-solvent catalyst. Generally, the maximum leach depth 120 may be about 50 μm to about 900 μm, such as 50 μm to about 400 μm. For example, the maximum leach depth 120 for the leached second region 122 may be about 300 μm to about 425 μm, about 350 μm to about 400 μm, about 350 μm to about 375 μm, about 375 μm to about 400 μm, or about 500 μm to about 650 μm. The maximum leach depth 120 may be measured inwardly from at least one of the major surface 112, the chamfer 114, or the peripheral surface 110. In some embodiments, the leach depth measured inwardly from the chamfer 114 and/or the peripheral surface 110 may be about 5% to about 30% less than the leach depth measured from major surface 112.
At least the second PCD region 118 has been fabricated in the presence of a one or more sp2-carbon-containing additives (e.g., graphite, graphene, fullerenes, ultra-dispersed diamond particles, or combinations of the foregoing) to impart a thermal stability to the second PCD region 118, a wear resistance to the second PCD region 118, a diamond density to the second PCD region 118, or combinations of the foregoing that is enhanced relative to the overlying first PCD region 116 prior to and/or after the leaching. For example, a diamond density of the second PCD region 118 may be about 1% to about 10% greater than a diamond density of the first PCD region 116, such as about 1% to about 5% or about 5% to about 10%. In some embodiments, part of the leached first PCD region 116 may have been fabricated in the presence of one or more sp2-carbon-containing additives.
Despite all or most of the first PCD region 116 not being fabricated in the presence of a one or more sp2-carbon-containing additives (e.g., graphite), the underlying more thermally-stable second PCD region 118 imparts sufficient thermal stability to the overall PCD table 102. Additionally, by leaching the first PCD region 116, the thermal-stability of the first PCD region 116 is improved, even if it is shallowly leached. Furthermore, by not fabricating the first PCD region 116 in the presence of one or more sp2-carbon-containing additives, the leachability of the metal-solvent catalyst from the first PCD region 116 may be substantially greater than the underlying second PCD region 118 at least partially due to the lower diamond density of the first PCD region 116.
Referring to the cross-sectional view in
In some embodiments, the one or more layers 304 may further include a plurality of sacrificial particles to improve the leachability of the metal-solvent catalyst from the first PCD region 116. For example, the sacrificial particles may be present in the one or more layers 304 in a concentration of greater than 0 wt % to about 15 wt %, about 1.0 wt % to about 10 wt %, about 1.0 wt % to about 5 wt %, about 1.5 wt % to about 2.5 wt %, about 1.0 wt % to about 2.0 wt %, or about 2.0 wt %, with the balance being the diamond particles. It is currently believed that relatively low amounts of the sacrificial particles (e.g., less than about 5 wt %, less than about 3 wt %, or less than about 2 wt %) increases accessibility for leaching the PCD table without significantly affecting the wear properties of the PCD table. The sacrificial particles may exhibit an average particle size (e.g., an average diameter) of about submicron to about 10 μm, about submicron to about 5 μm, less than about 5 μm, about submicron to about 2 μm, about submicron to about 1 μm, less than about 1 μm, or nanometer in dimensions such as about 10 nm to about 100 nm.
The sacrificial particles may be made from any material that exhibits a melting temperature greater than that of a melting temperature of the metal-solvent catalyst used to catalyze formation of PCD from the diamond particles and that is leachable from the PCD so formed via a leaching process. The sacrificial particles may be selected from particles made from metals, alloys, carbides, and combinations thereof that exhibit a melting temperature greater than that of a melting temperature of the metal-solvent catalyst used to catalyze formation of PCD from the diamond particles and that is leachable from the PCD so formed via a leaching process. For example, the sacrificial particles may be selected from particles made of refractory metals (e.g., niobium, molybdenum, tantalum, tungsten, rhenium, hafnium, and alloys thereof), other metals or alloys exhibiting a melting temperature greater than that of a melting temperature of the metal-solvent catalyst used to catalyze formation of PCD from the diamond particles and that is leachable from the PCD so formed via a leaching process, and combinations thereof. As another example, the sacrificial particles may be selected from particles of titanium, vanadium, chromium, iron, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, rhenium, any other metal or alloy that exhibits a melting temperature greater than that of a melting temperature of the metal-solvent catalyst used to catalyze formation of PCD from the diamond particles and that is leachable from the PCD so formed via a leaching process, alloys of any of the foregoing metals, carbides of any of the foregoing metals or alloys, and combinations of the foregoing. For example, in a more specific embodiment, the sacrificial particles may be selected from tungsten particles and/or tungsten carbide particles.
The plurality of diamond particles of the one or more layers 302, 304 may each exhibit one or more selected sizes. The one or more selected sizes may be determined, for example, by passing the diamond particles through one or more sizing sieves or by any other method. In an embodiment, the plurality of diamond particles may include a relatively larger size and at least one relatively smaller size. As used herein, the phrases “relatively larger” and “relatively smaller” refer to particle sizes determined by any suitable method, which differ by at least a factor of two (e.g., 40 μm and 20 μm). In various embodiments, the plurality of diamond particles may include a portion exhibiting a relatively larger size (e.g., 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm) and another portion exhibiting at least one relatively smaller size (e.g., 30 μm, 20 μm, 10 μm, 15 μm, 12 μm, 10 μm, 8 μm, 4 μm, 2 μm, 1 μm, 0.5 μm, less than 0.5 μm, 0.1 μm, less than 0.1 μm). In an embodiment, the plurality of diamond particles may include a portion exhibiting a relatively larger size between about 40 μm and about 15 μm and another portion exhibiting a relatively smaller size between about 12 μm and about 2 μm. Of course, the plurality of diamond particles may also include three or more different sizes (e.g., one relatively larger size and two or more relatively smaller sizes), without limitation.
In some embodiments, an average diamond particle size of the one or more layers 304 may be less than an average diamond particle size of the one or more layers 302. In such an embodiment, the first PCD region 116 may exhibit an average diamond grain size that is less than an average diamond grain size of the second PCD region 118. In other embodiments, an average diamond particle size of the one or more layers 304 may be greater than an average diamond particle size of the one or more layers 302. In such an embodiment, the first PCD region 116 may exhibit an average sintered diamond grain size that is greater than an average sintered diamond grain size of the second PCD region 118.
The one or more sp2-carbon-containing additives present in the one or more layers 302 may be selected from one or more sp2-carbon containing materials, such as graphite particles, graphene, fullerenes, ultra-dispersed diamond particles, or combinations of the foregoing. All of the foregoing sp2-carbon-containing additives at least partially include sp2 hybridization. For example, graphite, graphene (i.e., a one-atom-thick planar sheet of sp2-bonded carbon atoms that form a densely-packed honeycomb lattice), and fullerenes contain sp2 hybridization for the carbon-to-carbon bonds, while ultra-dispersed diamond particles contain a diamond core with sp3 hybridization and an sp2-carbon shell. The non-diamond carbon present in the one or more sp2-carbon-containing additives substantially converts to diamond during the HPHT fabrication process discussed in more detail below. The presence of the sp2-carbon-containing material during the fabrication of the PCD table 102 is believed to enhance the diamond density of the second PCD region 118 of the PCD table 102, the thermal stability of the second PCD region 118 of the PCD table 102, the wear resistance of the second PCD region 118 of the PCD table 102, or combinations of the foregoing relative to the first PCD region 116. For any of the disclosed one or more sp2-carbon-containing additives, the one or more sp2-carbon-containing additives may be selected to be present in a mixture of the one or more layers 304 with the plurality of diamond particles in an amount of greater than 0 wt % to about 20 wt %, such as about 1 wt % to about 15 wt %, about 2 wt % to about 10 wt %, about 3 wt % to about 6 wt %, about 3 wt % to about 8 wt %, about 4.5 wt % to about 5.5 wt %, or about 5 wt %.
The graphite particles employed for the non-diamond carbon may exhibit an average particle size of about 1 μm to about 20 μm (e.g., about 1 μm to about 15 μm or about 1 μm to about 3 μm). In some embodiments, the graphite particles may be sized fit into interstitial regions defined by the plurality of diamond particles. However, in other embodiments, graphite particles that do not fit into the interstitial regions defined by the plurality of diamond particles may be used because the graphite particles and the diamond particles may be crushed together so that the graphite particles fit into the interstitial regions. According to various embodiments, the graphite particles may be crystalline graphite particles, amorphous graphite particles, synthetic graphite particles, or combinations thereof. The term “amorphous graphite” refers to naturally occurring microcrystalline graphite. Crystalline graphite particles may be naturally occurring or synthetic. Various types of graphite particles are commercially available from Ashbury Graphite Mills of Kittanning, Pa.
An ultra-dispersed diamond particle (also commonly known as a nanocrystalline diamond particle) is a particle generally composed of a PCD core surrounded by a metastable carbon shell. Such ultra-dispersed diamond particles may exhibit a particle size of about 1 nm to about 50 nm and, more typically, of about 2 nm to about 20 nm. Agglomerates of ultra-dispersed diamond particles may be between about 2 nm to about 200 nm. Ultra-dispersed diamond particles may be formed by detonating trinitrotoluene explosives in a chamber and subsequent purification to extract diamond particles or agglomerates of diamond particles with the diamond particles generally composed of a PCD core surrounded by a metastable shell that includes amorphous carbon and/or carbon onion (i.e., closed shell sp2 nanocarbons). Ultra-dispersed diamond particles are commercially available from ALIT Inc. of Kiev, Ukraine. The metastable shells of the ultra-dispersed diamond particles may serve as a non-diamond carbon source.
One common form of fullerenes includes 60 carbon atoms arranged in a geodesic dome structure. Such a carbon structure is termed a “Buckminsterfullerene” or “fullerene,” although such structures are also sometimes referred to as “buckyballs.” Fullerenes are commonly denoted as Cn fullerenes (e.g., n=24, 28, 32, 36, 50, 60, 70, 76, 84, 90, or 94) with “n” corresponding to the number of carbon atoms in the “complete” fullerene structure. Furthermore, elongated fullerene structures may contain millions of carbon atoms, forming a hollow tube-like structure just a few atoms in circumference. These fullerene structures are commonly known as carbon “nanotubes” or “buckytubes” and may have single or multi-walled structures. 99.5% pure C60 fullerenes are commercially available from, for example, MER Corporation, of Tucson, Ariz.
The thickness of the one or more layers 302 may be about 5 to about 25 times greater than a thickness of the one or more layers 304, such as about 10 to about 25 or about 15 to about 20 times greater than the thickness of the one or more layers 304. For example, the thickness of the one or more layers 304 may be about 100 μm to about 1000 μm, such as about 100 μm to about 500 μm or about 150 μm to about 300 μm.
The assembly 300 including the substrate 104 and the one or more layers 302, 304 may be placed in a pressure transmitting medium, such as a refractory metal can embedded in pyrophyllite or other pressure transmitting medium. The pressure transmitting medium, including the assembly 300 enclosed therein, may be subjected to an HPHT process using an ultra-high pressure press to create temperature and pressure conditions at which diamond is stable. The temperature of the HPHT process may be at least about 1000° C. (e.g., about 1200° C. to about 1600° C.) and the pressure of the HPHT process may be at least 4.0 GPa (e.g., about 5.0 GPa to about 12 GPa or about 7.5 GPa to about 11 GPa) for a time sufficient to sinter the diamond particles to form a PCD table 102′ that is shown in
Upon cooling from the HPHT process, the PCD table 102′ becomes bonded (e.g., metallurgically) to the substrate 104. The PCD table 102′ includes a first PCD region 316 formed from the one or more layers 304 and the infiltrated metal-solvent catalyst and a second PCD region 318 formed from the one or more layers 302 and the infiltrated metal-solvent catalyst, with a boundary 317 between the first PCD region 316 and the second PCD region 318.
The thickness of the second PCD region 318 may be about 1 to about 15 times greater than a thickness of the first PCD region 316, such as about 1 to about 8 times. For example, the thickness of the first PCD region 316 may be about 100 μm to about 1000 μm, such as about 100 μm to about 500 μm or about 150 μm to about 300 μm.
During the HPHT process, metal-solvent catalyst from the substrate 104 may be liquefied and may infiltrate into the diamond particles of the one or more layers 302, 304 of diamond particles. The infiltrated metal-solvent catalyst functions as a catalyst that catalyzes formation of directly bonded-together diamond grains from the diamond particles to form the PCD table 102′. Also, the sp2-carbon-containing material of the one or more sp2-carbon-containing additives present in the one or more layers 302, such as graphite, graphene, fullerenes, the shell of the ultra-dispersed diamond particles, or combinations of the foregoing may be substantially converted to diamond during the HPHT process. The PCD table 102′ is comprised of a plurality of directly bonded-together diamond grains, with the infiltrated metal-solvent catalyst disposed interstitially between the bonded diamond grains.
In other embodiments, the metal-solvent catalyst may be mixed with the diamond particles of the one or more layers 302 and the diamond particles and the one or more sp2-carbon-containing additives of the one or more layers 304. In other embodiments, the metal-solvent catalyst may be infiltrated from a thin disk of metal-solvent catalyst disposed between the one or more layers 302 and the substrate 104.
Referring to
After forming the major surface 112 and the chamfer 114, the PCD table 102 may be leached in a suitable acid to form the leached first PCD region 116 (
In some embodiments, substantially the entire first PCD region 316 is leached. In other embodiments, the maximum leach depth 120 of the first PCD region 116 (
Although the methods described with respect to
In the second HPHT process, a cementing constituent from the new substrate 104 (e.g., cobalt from a cobalt-cemented tungsten carbide substrate) infiltrates into the at least partially leached PCD table. Upon cooling, the infiltrant from the new substrate 104 forms a strong metallurgical bonded with the infiltrated PCD table. In some embodiments, the infiltrant may be at least partially removed from the infiltrated PCD table of the new PDC in a manner similar to the way the PCD table 102 is leached in
In other embodiments, the PCD table 102 may be fabricated to be freestanding (i.e., not on a substrate) in a first HPHT process, leached, bonded to a new substrate 104 in a second HPHT process, and, if desired, leached after bonding to the new substrate 104.
The PDCs disclosed herein (e.g., the PDC 100 shown in
Thus, the embodiments of PDCs disclosed herein may be used on any apparatus or structure in which at least one conventional PDC is typically used. For example, in one embodiment, a rotor and a stator (i.e., a thrust bearing apparatus) may each include a PDC (e.g., the PDC 100 shown in
While various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting. Additionally, the words “including,” “having,” and variants thereof (e.g., “includes” and “has”) as used herein, including the claims, shall be opened ended and have the same meaning as the word “comprising” and variants thereof (e.g., “comprise” and “comprises”).
This application is a division of U.S. patent application Ser. No. 12/845,339 filed on 28 Jul. 2010, the disclosure of which is incorporated herein, in its entirety, by this reference.
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| Number | Date | Country | |
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| Parent | 12845339 | Jul 2010 | US |
| Child | 14615230 | US |
