Patent Application
20170057877
Wear-resistant, superabrasive compacts are utilized in a variety of mechanical applications. For example, polycrystalline diamond compacts (“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 (also known as a diamond body or table). The diamond body is formed and bonded to a substrate using an ultra-high pressure, ultra-high temperature (“HPHT”) process. The substrate is often brazed or otherwise joined to an attachment member, such as a stud or a cylindrical backing The substrate is typically made of tungsten or tungsten carbide.
A rotary drill bit typically includes a number of PDC cutting elements affixed to a drill bit body. 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. The PDC cutting element may also be brazed directly into a preformed pocket, socket, or other receptacle formed in the bit body.
Conventional PDCs are normally fabricated by placing a cemented carbide substrate into a container or cartridge with a volume of diamond crystals positioned on a surface of the cemented carbide substrate. A number of such cartridges may be loaded into an HPHT press. The substrates and volume of diamond crystals are then processed under HPHT conditions in the presence of a catalyst material that causes the diamond crystals to bond to one another to form a matrix of bonded diamond crystals defining a diamond body. The catalyst material is often a metal-solvent catalyst, such as cobalt, nickel, iron, or alloys thereof that is used for promoting intergrowth of the diamond crystals.
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 crystals into interstitial regions between the diamond crystals during the HPHT process. The cobalt acts as a catalyst to promote intergrowth between the diamond crystals, which results in formation of bonded diamond crystals. Often, a solvent catalyst may be mixed with the diamond crystals prior to subjecting the diamond crystals and substrate to the HPHT process. During the HPHT process other components of the cemented carbide substrate, such as tungsten and carbon, may also migrate into the interstitial regions between the diamond crystals. The diamond crystals become mutually bonded to form a matrix of polycrystalline diamond (“PCD”, also referred to as a PCD body or PCD table), with interstitial regions between the bonded diamond crystals being occupied by the solvent catalyst.
The presence of the solvent catalyst in the diamond body is believed to reduce the thermal stability of the diamond body at elevated temperatures. For example, the difference in thermal expansion coefficient between the diamond grains and the solvent catalyst is believed to lead to chipping or cracking in the PDC during drilling or cutting operations, which consequently can degrade the mechanical properties of the PDC or cause failure. Additionally, some of the diamond grains can undergo a chemical breakdown or back-conversion to graphite via interaction with the solvent catalyst. At extremely high temperatures, portions of diamond crystals may transform to carbon monoxide, carbon dioxide, graphite, or combinations thereof, thus, degrading the mechanical properties of the PDC. One conventional approach for improving the thermal stability of PDCs is to at least partially remove the solvent catalyst from the PDC by acid leaching.
Therefore, manufacturers and users of PDCs continue to seek PDCs having improved thermal stability.
Embodiments of the invention relate to methods of fabricating nanoparticle infiltrated PCD bodies and PDCs in which the nanoparticle infiltrated/infused region impedes infiltration/infusion of a metallic infiltrant under HPHT conditions, resulting PCD bodies and PDCs, and applications for such PCD bodies and PDCs. Infiltrating/infusing at least a portion of a PCD body with nanoparticles prior to bonding the PCD body to a substrate may improve the thermal and/or mechanical properties of the resulting PDC.
In an embodiment, a method of fabricating a PDC includes forming a PCD body including a plurality of bonded diamond grains defining a plurality of interstitial spaces in which a catalyst (e.g., metal-solvent catalyst) is disposed. The PCD body may then be leached to at least partially remove the catalyst therefrom. The at least partially leached PCD body may then be infiltrated/infused with nanoparticles to limit or reduce subsequent infiltration of another material into a portion of the at least partially leached PCD body. The at least partially leached and nanoparticle infiltrated PCD body may be bonded to substrate in a second HPHT process to form a PDC. The resulting PCD body of the PDC includes at least a region having constituent infiltrant (i.e., infiltrant comprising a constituent of a substrate) therein, and a region containing nanoparticles therein. Such regions may overlap, may be the same region, or may be separate.
In an embodiment, a PDC includes a substrate including a constituent infiltrant therein and a PCD body defining an upper surface and a back surface spaced therefrom. The PCD body includes a plurality of bonded diamond grains defining plurality of interstitial spaces therebetween, a constituent infiltrant infiltrated region extending from at least the back surface to an intermediate depth, and a nanoparticle containing region extending from at least the intermediate depth toward the upper surface. The constituent infiltrant infiltrated region includes the constituent infiltrant occupying at least a portion of the plurality of interstitial spaces therein. The nanoparticle containing region includes nanoparticles occupying at least a portion of the plurality of interstitial spaces therein.
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 or similar elements or features in different views or embodiments shown in the drawings.
Embodiments of the invention relate to PDCs including a nanoparticle infiltrated/infused PCD body (e.g., PCD table), and methods of fabricating such PCD and PDCs. The disclosed PCD bodies include a nanoparticle containing region or portion in which infiltration or diffusion of a subsequent material through or past the nanoparticle containing region is limited or prevented. The disclosed PDCs may be used in a variety of applications, such as rotary drill bits, bearing apparatuses, wire-drawing dies, machining equipment, and other articles and apparatuses.
The bonded and infiltrated PCD body 128 includes a constituent infiltrant infiltrated region 129 disposed in a second portion of the interstitial regions, with the constituent infiltrant infiltrated region 129 extending inwardly from the back surface 140. The constituent infiltrant infiltrated region 129 may extend inwardly from the back surface 140 to at least the intermediate depth d. The nanoparticle infiltrated region 129 may prevent, limit, or impede infiltration/infusion of constituents from a substrate 150 from infiltrating/infusing into a PCD body beyond or into the nanoparticle-containing region 127, thereby creating a more thermally-stable region (e.g., such that it may not need to be subsequently leached). Optionally, nanoparticle-containing region 127 may be leached. In an embodiment, the constituent infiltrant infiltrated region 129 may be formed at least partially by the constituent infiltrant (e.g., cobalt from a cobalt-cemented tungsten carbide substrate) sweeping into the interstitial spaces of the PCD body from the substrate 150 at an interfacial surface 145 thereof.
The bonded and infiltrated PCD body 128 is bonded to the substrate 150 at the interfacial surface thereof. Although the upper surface 130 and the back surface 140 are illustrated as being substantially planar, the upper surface 130 and/or the back surface 140 may be nonplanar (e.g., convex, grooved, dimpled, textured, concave, or combinations thereof) and a working region of the bonded and infiltrated PCD body 128 may include peripheral portions of the nanoparticle containing region(s) 127. Suitable materials for the substrate 150 include cemented carbides, such as titanium carbide, niobium carbide, tantalum carbide, vanadium carbide, tungsten carbide, or combinations of any of the preceding carbides cemented with iron, nickel, cobalt, or alloys thereof. In an embodiment, the substrate 102 may comprise cobalt-cemented tungsten carbide.
A catalyst may be provided in particulate form mixed with the diamond particles, as a thin foil placed adjacent to the mass of diamond particles, from a cemented carbide substrate including a metal-solvent catalyst therein (e.g., cobalt from a cobalt-cemented tungsten carbide substrate), or combinations of the foregoing. The PCD body 122 may be formed alone as described above or integrally formed on a substrate. In an embodiment, the diamond particles 120 may be positioned adjacent to the substrate, wherein the substrate includes catalyst therein. Both the plurality of diamond particles 120 and a substrate may be placed in a pressure transmitting medium substantially as described above, wherein the plurality of diamond particles 120 and the substrate are positioned adjacent to one another. The pressure transmitting medium, including the diamond particles 120 and substrate, are subjected to the first HPHT process substantially as described above, wherein the diamond particles 120 and substrate bond together when the catalyst material from the substrate sweeps into the diamond particles to both catalyze diamond-to-diamond bonding as described above and subsequently cools in the interstitial regions of the PCD body. The amount of catalyst that infiltrates into the resulting PCD body depends at least partially on the size and/or distribution of the interstitial regions in the PCD body. In such and embodiment, it may be necessary to remove the PCD body from the substrate in order to perform the subsequent acts described herein on the PCD body such as, for example, leaching and/or nanoparticle infiltration. In other embodiments, at least some of the subsequent acts described herein may be performed with the PCD body remaining bonded to the substrate.
The diamond particle size distribution of the plurality of diamond particles 120 may exhibit a single mode, or may be a bimodal or greater grain size distribution. In an embodiment, the diamond particles 120 may comprise 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 (by any suitable method) that differ by at least a factor of two (e.g., 30 μm and 15 μm). According to various embodiments, the diamond particles 120 may include a portion exhibiting a relatively larger average particle size (e.g., 200 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 average particle size (e.g., 6 μm, 5 μm, 4 μm, 3 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 diamond particles 120 may include a portion exhibiting a relatively larger average particle size between about 10 μm and about 40 μm and another portion exhibiting a relatively smaller average particle size between about 1 μm and 4 μm. In some embodiments, the diamond particles 120 may comprise three or more different average particle sizes (e.g., one relatively larger average particle size and two or more relatively smaller average particle sizes), without limitation.
It is noted that the diamond grain size of the as-sintered diamond particles (i.e., diamond grains) may differ from the average particle size of the mass of diamond particles prior to the first HPHT process due to a variety of different physical processes, such as grain growth, diamond particle fracturing, carbon provided from another carbon source (e.g., dissolved carbon in the metal-solvent catalyst), or combinations of the foregoing.
The interstitial region size or average interstitial region size may depend at least partially on the average diamond particle size or the smallest average diamond particle size used in a multimodal diamond particle mixture (i.e., diamond particle mixture having more than one average diamond particle size mixed therein). Interstitial regions and bonded diamond grains may collectively define pore throats between the interstitial regions. Pore throats are the openings connecting adjacent interstitial regions. Smaller pore throats may inhibit infiltration of larger materials into PCD bodies, while larger pore throats will allow such infiltration. Pore throat sizes may vary for a number of reasons including by way of non-limiting example, the size or sizes of the diamond particle sizes used, the shape of the diamond particles used, the extent of diamond-to-diamond bonding between diamond particles, HPHT sintering conditions, or combinations of the foregoing. Pore throat sizes may include sub-nanometer (nm) scale pore throats to micrometer scale pore throats. In an embodiment, an average pore throat size may be achieved. According to various embodiments, pore throats may exhibit an average size smaller than about 20 μm, 5 μm, 1 μm, 500 nm, 200 nm, 100 nm, 50 nm, 25 nm, 15 nm, 10 nm 5, nm, 2 nm, 1 nm, and 500 pm. Pore throat characteristics may be analyzed and determined using porosimetry techniques, including those described in U.S. Patent Application No. 61/846,138 filed on 15 Jul. 2013, which is incorporated herein, in its entirety, by this reference. In an embodiment, manufacturing a PCD body may include selecting and/or using a specific size of diamond powder to obtain a specific interstitial region distribution, size, or average interstitial region size. In an embodiment, manufacturing a PCD body may include selecting and/or using a specific size of diamond powder to obtain specific pore throat sizes, or average pore throat sizes.
While the catalyst material promotes diamond-to-diamond bond growth between diamond particles, the catalyst material disposed within the interstitial spaces created by bonded diamond grains may decrease the thermal stability and/or mechanical strength of a PCD body in some circumstances. A catalyst material having a higher coefficient of thermal expansion than the diamond may cause the PCD body to chip, crack, spall, or fail during use. Therefore, it may be desirable to control the extent and/or depth of catalyst infiltration into a PCD body. PCD bodies having cobalt disposed therein may experience cracking or failure at temperatures above about 700-800° C. due to cobalt's higher coefficient of thermal expansion than the bonded diamond grains. The expansion of cobalt may exert stresses on the bonded diamond grains from the interstitial spaces therein, resulting in chipping, cracking, spalling, and failure of the PCD body. Therefore, it may be desirable to leach the cobalt or other catalyst material from a PCD body.
In an embodiment, PCD body 122 may be rendered substantially free of the catalyst disposed therein by subjecting the PCD body to a leaching process. Conventional leaching processes include disposing (i.e., partially or completely immersing) the PCD body 122 including the catalyst therein into a leaching agent configured to at least partially remove the catalyst from the PCD body 122 to a desired depth. Suitable leaching vessels may include a pressure vessel, a stainless steel vessel, a stainless steel vessel lined with PTFE (i.e., Teflon®) or another lining suitable to withstand acidic conditions at high temperatures, or combinations of the foregoing. In embodiments, the leaching agent may comprise one or more of aqua regia, hydrochloric acid, nitric acid, hydrofluoric acid, other suitable acids, supercritical fluids, or combinations thereof. In an embodiment, the leaching agent and PCD body 122 may be subjected to elevated temperature and/or pressure. For example, in an embodiment, the PCD body 122 having catalyst therein (depicted in
In an embodiment, leaching the catalyst from the PCD body 122 may be accomplished by pressurized leaching. In an embodiment, the PCD body 122 may be subjected to or otherwise soaked in a leaching agent substantially as described above under elevated pressure and/or elevated temperature conditions to leach the catalyst therefrom. In an embodiment, the PCD body 122 and the leaching agent may be disposed in a sealed leaching vessel comprising a pressure vessel including stainless steel construction optionally having a PTFE liner therein. The contents of, or the entire leaching vessel may be subjected to elevated temperature, thereby raising the vapor pressure inside of the pressure vessel, thereby increasing the rate at which the PCD body is leached. In an embodiment, the PCD body 122 may be leached in a matter of hours under elevated temperature and elevated pressure rather than days or weeks in conventional leaching processes. In an embodiment, the PCD body 122 may be leached using a leaching agent having a supercritical component in which the leaching is agent brought to a supercritical state by elevating the pressure and temperature of the leaching agent having a supercritical component. Leaching may be accomplished using supercritical fluid according to leaching methods described in U.S. Patent Application No. 61/897,764 filed on 30 Oct. 2013, the disclosure of which is incorporated herein, in its entirety, by this reference.
In embodiments such as those depicted in
In an embodiment, such as that depicted in
After leaching, the at least partially leached PCD body 124 may be substantially free of the catalyst material within at least a portion of interstitial spaces in at least one region of the at least partially leached PCD body 124. The empty interstitial spaces provide interconnectivity between adjacent interstitial spaces creating interconnected interstitial (porous) paths or pores (e.g., nanopores and/or micropores) and pore throats therebetween. The interconnected interstitial spaces or pores may create a relatively free path from one region of an at least partially leached PCD body 124 to another region of the at least partially leached PCD body 124. In an embodiment, the interstitial path from one region of a PCD body to another may be more or less tortuous based on one or more factors including, by way of non-liming example, average pore throat size in the path, the smallest pore throat size in the path, diamond powder and/or grain size, diamond grain shape, and nanoparticle size/shape. In an embodiment, the at least partially leached PCD body 124 may include one or more interconnected interstitial (porous) paths, being substantially free of catalyst material, wherein the interconnected interstitial (porous) path may extend from the upper surface 130 to at least an intermediate depth d. In an embodiment, the now empty or substantially empty interstitial spaces may be infiltrated/infused with another material, such as by way of non-limiting example, nanoparticles, metallic infiltrant, non-metallic infiltrant, catalyst, or combinations of the foregoing. In embodiments, such material may be infiltrated/infused into the PCD body 124 through such interstitial spaces and pore throats to a depth within the PCD body 124.
In an embodiment, the region containing nanoparticles may be at least partially leached. A region of a PCD body may be leached, infiltrated/infused with nanoparticles, and then at least partially leached to remove a portion of or all of the nanoparticles from a region of the nanoparticle-containing region. The rest of the PCD body or a portion of the PCD body may be protected from such leaching by control of leaching process conditions such as any of those described above, or may be protected by masking a portion thereof. Masking includes placing a protective coating over a portion of a PCD body in which the material therein is to be retained, such that the leaching agent does not penetrate into the portion of the PCD body behind the mask. Examples of methods of leaching using masks and masking techniques are described in U.S. Provisional Patent Application No. 61/728,953, and U.S. patent application Ser. No. 13/751,405, which are incorporated herein in their entirety by this reference.
In cross-sectional views of embodiments depicted in
While embodiments have been described wherein the nanoparticles are infiltrated/infused to an intermediate depth d, nanoparticles may infiltrate or infuse into the entire depth of a PCD body such as that depicted in
The intermediate depth d may extend a selected distance into a PCD body. In an embodiment, the intermediate depth d may extend at least about 50 μm into a PCD body, for example, at least about 100 μm, 200 μm, 500 μm, 1000 μm, or about 1200 μm into the PCD body from the upper surface thereof. In an embodiment, the intermediate depth d may extend about 50 μm to about 1000 μm, such as about 200 μm to about 800 μm, about 300 μm to about 700 μm, about 200 μm to about 500 μm, about 500 μm to about 700 μm, or about 700 μm to about 1000 μm into the PCD body from the upper surface thereof. In an embodiment, the intermediate depth d may be defined at least in part relative to the thickness of the PCD body. For example, the intermediate depth d may be about ninety percent (90%) or less of the thickness of the PCD body, about eighty percent (80%) of the thickness of the PCD body, about seventy-five percent (75%) of the thickness of the PCD body, about fifty (50%) percent of the thickness of the PCD body, about twenty-five (25%) percent of the thickness of the PCD body, or about ten percent (10%) of the thickness of the PCD body.
In an embodiment, the least partially leached and at least partially nanoparticle infiltrated/infused PCD body 126 may be bonded to a substrate 150 after nanoparticle infiltration.
In an embodiment, the constituent infiltrant may only infiltrate/infuse as far into the PCD body as the interstitial regions remain unoccupied. Accordingly, in an embodiment, nanoparticle being present may define a depth of nanoparticle-containing region 127 into which the constituent infiltrant may not extend or in which infiltration into the nanoparticle-containing region 127 is limited. In an embodiment, the nanoparticle-containing region 127 extends to the depth d and some of the interstitial spaces or substantially all of the interstitial spaces are filled with nanoparticles. Infiltration of the constituent infiltrant may not progress into the nanoparticle-containing region 127 or may be limited by the region 127 so that any infiltration of the constituent infiltrant is less than if the nanoparticles where not present. In an embodiment, the constituent infiltrant may be present in both regions 127 and 129. The amount of constituent infiltrant in the nanoparticle-containing region 127 may be less than that present in the constituent infiltrant region 129 before optional leaching of the PCD body. For example, the constituent infiltrant may comprise more than about 6 wt % of the region 129, such as about 6 wt % to about 8 wt % of the region 129. The constituent infiltrant may comprise less than about 5 wt % of the nanoparticle-containing region 127. For example, the constituent infiltrant may comprise about 4 to 5 wt %, about 3-5 wt %, about 2-3 wt %, or less than about 3 wt % of the nanoparticle-containing region 127. In an embodiment, a braze material may be placed between the PCD body 126 and the substrate 150, which are all placed in a pressure transmitting medium substantially as described above, the pressure transmitting medium may be brought to a pressure and temperature sufficient to melt the braze material which may then sweep into the PCD body and the substrate 150, thereby bonding the two together. In other embodiments, the brazing may not be conducted under HPHT conditions. For example, vacuum brazing may be used to bond the substrate 150 to PCD body.
In an embodiment, a bonded and infiltrated PCD body 128″ may be leached subsequent to bonding with the substrate 150. For example,
A residual amount of constituent infiltrant (e.g., cobalt from a cobalt-cemented tugnsten carbide substrate) may remain in each of the regions of the at least partially leached PCD table after leaching. Accordingly, at least a residual amount of metal-solvent catalyst (e.g., about less than 2 wt %, about 1 to about 2 wt %, or about 0.5 to about 0.85 wt %) may remain in one or more of the at least partially leached region 125, the nanoparticle-containing region 127, or the constituent infiltrant containing region 129 after bonding and/or nanoparticle infiltration. As noted above, in some embodiments, the nanoparticle-containing region 127 may only limit or partially block constituent infiltrant from infiltrating into the nanoparticle-containing region 127 and beyond into the at least partially leached region 125 during the second high pressure/high temperature process. Such a PCD body may comprise less constituent infiltrant in the at least partially leached region 125 than in the nanoparticle-containing region 127, and the constituent infiltrant containing region 129. Therefore, in embodiments, the nanoparticle-containing region 127 and/or the at least partially leached region 125 may be subsequently leached of constituent infiltrant present in those regions after bonding (i.e., after the second HPHT process). Infiltrated PCD bodies, according to any embodiment, may be subsequently leached after infiltration with nanoparticles (e.g., before or after bonding with a substrate). Optionally, nanoparticles may be at least partially removed by such leaching, without limitation. By way of non-limiting example, region 125 in
In an embodiment, the nanoparticles infiltrate/infuse into the at least partially leached PCD body 124 in such a manner as to create a concentration gradient of the nanoparticles in which the portion of the at least partially leached PCD body 124 near upper surface 130 is substantially completely filled with nanoparticles and the region nearer the back surface 140 is substantially completely empty of nanoparticles. In an embodiment depicted in
In an embodiment, a chamfer 137, substantially as depicted in
In an embodiment, the interior volume 235 may include the fluid 215 and nanoparticles 210. In an embodiment, pressure may be applied to the interior volume, whereby the fluid 215 having the nanoparticles 210 suspended therein may be diffused through the interstitial regions of the at least partially leached PCD body 124. In an embodiment, pressure may be applied to the interior volume 235 and thereby to the fluid 215, whereby the fluid 215 having the nanoparticles 210 suspended therein may be diffused through the interconnected interstitial spaces of the at least partially leached PCD body 124 positioned therein from the upper surface 130 generally toward the back surface 140. In an embodiment, pressure may be applied to the fluid 215 in the interior volume 235 via a pressure source 270 in communication with the inlet 260. In an embodiment, the pressure source 270 may include a high-pressure pump. In an embodiment, the fluid 215 and the nanoparticles 210 may be pumped into the interior volume by the pressure source 270, thereby providing increased pressure to the interior volume 235. In an embodiment the pressure applied to the fluid 215 having nanoparticles 210 therein may be a pressure slightly above ambient pressure for example, above about 0.102 MPa, above about 20 MPa, above about 50 MPa, above about 100 MPa, above about 200 MPa, above about 350 MPa, or above about 500 MPa. In an embodiment, the suitable pressure range for infiltration/infusion may include about 0.102 MPa to about 500 MPa, for example, about 50 MPa to about 400 MPa, or about 100 MPa to about 350 MPa. The pressure exerted on the fluid may be elevated before and/or the nanoparticles have been suspended therein.
In an embodiment, the fluid 215 may travel through the interconnected interstitial spaces 165 of the at least partially leached PCD body 124, from the upper surface 130 to the back surface 140, carrying the nanoparticles 210 through the PCD body 124, thereby infiltrating/infusing substantially the entire PCD body 124 with nanoparticles 210. In an embodiment depicted in
In embodiments, the orientation of the PCD body and the infiltration apparatus 200 may vary. For example, in an embodiment, the infiltration apparatus 200 may be positioned vertically such that the PCD body 124 therein is on the bottom of the infiltration apparatus 200, and gravity may assist in infiltration/infusion of nanoparticles therein. Further, a vertical configuration may have the added benefit of aiding in even/uniform distribution of nanoparticles along the entire area of the PCD body 124.
During infiltration/infusion it may be necessary to support the PCD body 124 against the bending stresses exerted by the pressure of the applied fluid on the PCD body. The retaining ring may be configured to support the PCD body across the entire back surface 140 or substantially the entire back surface 140 thereof. For example, the retaining ring may extend from the lateral surface 135 of the PCD body 124 across the entire back surface 140 of the PCD body 124. In order to maintain flow, such a retaining ring, may be configured to allow for fluid to travel therethrough. In an embodiment, a retaining ring may include vent holes cut therein. The vent holes may be provided in a number or pattern therein to achieve the desired amount of flow of fluid and nanoparticles through the PCD body 124 supported therein. For example, a retaining ring that extends substantially across the entire back surface 140 of a PCD body 124 may have hundreds of vent holes or less therein, the vent holes may have any number of differing sizes, for example more than about 1 nm, such as about 5 nm to about 50,000 μm. In an embodiment, the retaining ring may comprise a high permeability ceramic, having no vent holes cut therein. In an embodiment, an infiltration apparatus 200 may include a retaining ring comprising vent holes therein in and a high permeability ceramic disposed between the retaining ring and the PCD body 124, whereby the high permeability ceramic supports the PCD body, and allows flow of fluid and nanoparticles therethrough.
The plurality of vent holes 244 on the retaining ring 240′ may be radially distributed thereon. The plurality of vent holes 244 may include two or more vent holes, such as more than vent 10 holes, between 2 and 20 vent holes, between 4 and 10 vent holes, 6 holes, or 8 vent holes. The plurality of holes 244 may exhibit any number of vent hole sizes, for example, an individual vent hole be about more than about 0.01 inches wide, more than about 0.02 inches wide, such as about 0.05 inches wide, or about 0.1 inches wide, between about 0.02 inches and about 0.3 inches wide. Vent hole width as discussed herein is intended to refer to the size of the vent hole at its widest, which may be at the outer periphery of the retaining ring. A retaining ring 240′ having a plurality of vent holes therein may exhibit a uniform vent hole size. In another embodiment, the plurality of vent holes 244 may exhibit one or more vent hole size. The vent holes 244 may be spaced at even intervals radially about the periphery of the retaining ring 240′. In an embodiment, the vent holes 244 may be in sufficient number and width to allow flow/infiltration of nanoparticles through a substantially continuous region of the PCD body, such as the entire upper surface 130, or a region about the periphery of the PCD body, thereby creating a substantially continuous infiltrated region therein. The substantially continuous infiltrated region may be disposed at least about the periphery of the PCD body, or at least at a side surface of the PCD body. In an embodiment, the vent holes 244 may be spaced apart to create an intermittent pattern of gaps between infiltrated regions in the PCD body. In an embodiment, vent holes 244 may be spaced in an in an even or uneven pattern about the retaining ring 240′. By way of non-limiting example, a group of vent holes 244 may be placed radially opposite a single vent hole in a retaining ring 240.′
In embodiments, nanoparticles suitable for infiltration/infusion into the at least partially leached PCD body 124 may include non-solvent materials. At elevated temperatures, materials generally non-catalytic relative to diamond do not promote chemical breakdown or back-conversion of the diamond grains to graphite, carbon monoxide, carbon dioxide, or combinations thereof, which results in degradation of the mechanical properties of the PCD body. Non-solvent nanoparticles may include, by way of non-limiting example, nanodiamond particles (e.g., ultra-dispersed diamond particles), refractory metals, metalloids, metal oxides, metal carbides, metal nitrides, glass, or combinations of the foregoing.
Suitable glasses for the nanoparticles may include, but are not limited to, a silicate glass, a borate glass, a phosphate glass, a borosilicate glass, or combinations of any of the foregoing glasses. For example, the nanoparticles may comprise sodium silicate, zirconium silicate, lithium silicate, sodium borosilicate, zirconium borosilicate, lithium borosilicate, lithium aluminosilicate, or combinations thereof. In some embodiments, any of the foregoing glasses may be reinforced with a filler made from ceramic particles. For example, the ceramic particles may include, but are not limited to, boron nitride particles, titanium diboride particles, zirconium oxide particles, and combinations of the foregoing ceramic particles.
Suitable metals used in metal oxide, metal carbide, or metal nitride nanoparticle infiltrants may include refractory metals, including, but not limited to, one or more of titanium, vanadium, chromium, molybdenum, and tungsten. In an embodiment, metal oxide nanoparticles may include aluminum oxide or zirconium oxide. In an embodiment, a metal nitride nanoparticles may include, by way of non-limiting example, zirconium nitride, tungsten nitride, vanadium nitride, tantalum nitride, or niobium nitride. In another embodiment, a suitable nanoparticles may include boron nitride or silicon nitride. In an embodiment, a metal carbide may comprise an interstitial carbide including, but not limited to, titanium carbide, tungsten carbide, zirconium carbide, and molybdenum carbide. In an embodiment, suitable nanoparticles may comprise one or more different materials.
In an embodiment, the non-solvent material may be selected based on at least the coefficient of thermal expansion of said material. Materials having a higher coefficient of thermal expansion than diamond tend to cause breaking, spalling, and cracking of PCD bodies when exposed to elevated temperatures. For example, a PCD body having cobalt disposed in interstitial regions therein will degrade over about 700° C. because the coefficient of thermal expansion for cobalt is higher than that of diamond which causes the cobalt to expand inside of the PCD body thereby causing stress and breakage from the inside of the PCD body. By providing a nanoparticles that exhibit a negative or even a small positive coefficient of thermal expansion, thermal stresses and/or thermal damage (e.g., breaking diamond-to-diamond bonds) may be reduced as the temperature of the PCD body increases during use (e.g., during cutting a subterranean formation during drilling) as compared to when the material in the interstitial region has a much larger coefficient of thermal expansion, such as a metal-solvent catalyst like cobalt. In an embodiment, an nanoparticle material with a coefficient of thermal expansion less than or closely matching that of diamond, or at least less than the solvent-metal catalyst used to form the PCD is selected to infiltrate/infuse into the PCD body. Suitable material having a coefficient of thermal expansion closely matching that of the PCD body or at least less than that of the solvent-metal catalyst used to form the PCD body may include UDD particles, silicon, silicone, or combinations thereof.
In an embodiment, a nanoparticle material having a negative coefficient of thermal expansion is used to infiltrate the PCD body. Materials having a negative coefficient of thermal expansion include, by way of non-limiting example, zirconium tungstates particles, beta spodumene particles, beta eucryptite particles, or combinations thereof.
In embodiments, nanoparticles suitable for infiltration may be selected based at least partially on average nanoparticle size. In embodiments, suitable nanoparticles may exhibit an average size smaller than about: 20 μm, 5 μm, 1 μm, 500 nm, 200 nm, 100 nm, 50 nm, 25 nm, 15 nm, 10 nm 5, nm, 2 nm, 1 nm, or 500 μm. In embodiments, suitable nanoparticles may exhibit an average size of about 5 nm to about 800 nm, about 200 nm to about 900 nm, or about 100 nm to about 500 nm. In an embodiment, more than one size and/or type of nanoparticle may be used. In an embodiment, the nanoparticle infiltrants may include a portion exhibiting a relatively larger average nanoparticle size between about 5 μm and about 1 μm and another portion exhibiting a relatively smaller average nanoparticle size between about 500 nm and 1 nm. In some embodiments, the nanoparticles may comprise three or more different average nanoparticle sizes (e.g., one relatively larger average nanoparticle size and two or more relatively smaller average particle sizes), without limitation.
In an embodiment, nanoparticles 210 may be disposed in, suspended in, dispersed in, combinations thereof, or otherwise carried in the fluid 215. In an embodiment, the fluid 215 comprising nanoparticles may be diffused through the at least partially leached PCD body 124 to form the infiltrated PCD body 126. Suitable fluids may include, by way of non-limiting example, fluids that will not react with the PCD body, fluids that will not react with the nanoparticles, fluids with density sufficient to suspend nanoparticles, fluids that with viscosity sufficient to allow the fluid to diffuse through the empty interstitial regions in a PCD body, fluids that may dry or otherwise evaporate readily upon heating, and/or combinations of one or more of the foregoing. In an embodiment, the fluid may comprise one or more of water and organic solvents, including polar and non-polar solvents. Suitable organic solvents may include one or more of alcohol, dichloromethane (DCM), tetrahydrofuran (THF), dimethyl sufloxide (DMSO), pentane, hexane, chloroform, carbon tetrachloride, and/or combinations of one or more of the foregoing. In an embodiment, the fluid may comprise a surfactant. In an embodiment, a fluid may be selected/used to infiltrate or diffuse through a PDC body based at least on fluid density and/or viscosity. Fluids, as discussed herein, may be a liquid or a gas.
In an embodiment, the nanoparticles 210 may be suspended and/or dispersed in the fluid 215 by mixing into the fluid while stirring or otherwise agitating the fluid to create a substantially uniform distribution of the nanoparticles 210 within the fluid 215. In an embodiment, the nanoparticles 210 may be suspended in only a portion of the fluid 215 diffused through a PCD body 124. In an embodiment, nanoparticles may be supplied to the fluid during only a portion of the duration in which a fluid is diffused into the PCD body 124. For example, nanoparticles 210 may be added to or otherwise disposed in a fluid 215 for a short time during infiltration wherein the nanoparticles are diffused a distance through or into a selected region of the PCD body from the upper surface 130 toward the back surface 140 until they are stopped according to any manner disclosed above, whereby the resulting PCD body may resemble at least partially leached and infiltrated PCD body 126′, 126″, 132, 132′, or 132″ depicted in
In an embodiment, a gradient of diamond particles may be selected to create a gradient of sintered diamond grains after the first HPHT process in which the gradient of diamond grains may allow for infiltration/infusion of nanoparticles in a gradient such as that depicted in
In an embodiment, the average diamond particle size may be selected based on the desired average pore throat size. In an embodiment, average pore throat size may be selected based on the desired nanoparticle size or composition. Nanoparticle size may be selected based on the desired nanoparticle infiltration depth for a given PCD body. In an embodiment, nanoparticle size may be selected based on average pore throat size, for example, nanoparticles 210 having a size closely matching that of the average pore throat size with travel through a PCD body more slowly and become lodged in the PCD body more quickly than nanoparticles having a size considerably smaller than the average pore throat size. In embodiments, controlling the depth and extent of infiltration/infusion may include selecting a desired combination of one or more of average diamond particle size; diamond layer number, thickness, and average diamond particle size; catalyst material amount and type used in the first HPHT sintering; first HPHT sintering conditions; leaching depth; nanoparticle type and size; and fluid type, density and viscosity.
The method 300 of making a PDC includes an act 310 of forming a PCD body, and act 320 of leaching the PCD body, an act 330 of causing at least a region of the PCD body to be occupied by nanoparticles, and an act 340 of bonding the PCD body to a substrate.
In an embodiment, the act 310 of forming a PCD body may include subjecting diamond particles having an average particle size of about 20 μm having metal-solvent catalyst powder comprising cobalt dispersed therein, to a first HPHT process including a cell pressure of about 7.7 GPa and a temperature of about 1400° C. In an embodiment a larger average diamond particle size may be used, for example, the average diamond particle size may be about 30 μm. In an embodiment, a multimodal diamond powder mixture may be used, for example, diamond powders exhibiting an average diamond particle size of 20 μm and 40 μm respectively may be mixed together. In an embodiment, the cell pressure may be higher, for example, about 9 GPa may be used to form a PCD body. In an embodiment, a higher temperature may be used in the first HPHT process, for example, above about 1500° C. In another embodiment, the act 310 of forming a PCD body may include subjecting diamond particles having an average particle size of about 20 μm positioned adjacent to a cobalt cemented tungsten-carbide substrate in a pressure transmitting medium to the first HPHT described above. The resulting PCD body 122 may be separated from the substrate by one of lapping, EDM machining, or grinding.
In an embodiment of the act 320 of leaching a PCD body, the PCD body 122 having catalyst therein may be leached by exposure to acid in a leaching vessel. The acid may be at a temperature above ambient temperature, for example above about 30° C. or above about 100° C. In an embodiment, the rinsing vessel may be sealed and the acid disposed therein may be subjected to elevated pressure. The elevated pressure may be created by heat applied to the leaching vessel and/or acid thereby increasing vapor pressure in the leaching vessel. In an embodiment, the leaching agent may be one or more of hydrochloric acid, nitric acid, hydrofluoric acid, or aqua regia. In embodiments, the leaching time may be about 4 weeks, 2 weeks, a week, 5 days, 3 days, 2 days, or 1 day. In an embodiment, the resulting at least partially leached PCD body 124 may be cleaned to remove the leaching agent and/or leaching agent by-product by exposure to water for more than a day. Further cleaning processes, HPHT processes, and resultant PDCs may be formed according to the techniques disclosed in U.S. Pat. No. 7,845,438, which is incorporated herein, its entirety, by this reference.
In an embodiment of the act 330 causing at least a region of a PCD body to be occupied by nanoparticles, the at least partially leached PCD body 124 may be infiltrated with the nanoparticles 210. In an embodiment, nanoparticles 210 may include one or more of UDD particles, metal oxides, metal nitrides, metal carbides, glass, silicon, silicone, or copper. In an embodiment, the nanoparticles 210 may exhibit an average size of more than about 1 nm, such as about 5 nm, about 25 nm, about 50 nm, about 100 nm, about 500 nm, about 1000 nm, about 5 nm to about 1000 nm, or about 10 nm to about 500 nm. The nanoparticles 210 may be suspended in a fluid 215. In an embodiment, suitable fluids 210 may include commonly known or recognized fluids which do not degrade or dissolve the nanoparticles or diamond, such as by way of non-limiting example water, alcohol, DCM, THF, DMSO, or combinations thereof. In embodiments, the nanoparticles 210 may be mixed in the fluid 215 in such a manner as to create a substantially uniform distribution of the nanoparticles 210 in the fluid 215.
In an embodiment, the act 330 of causing at least a region of a PCD body to be occupied by nanoparticles may include placing the at least partially leached PCD body 124, substantially as depicted in
In an embodiment of the act 330 of causing at least a region of a PCD body to be occupied by nanoparticles, the pressure exerted on the fluid 215 having nanoparticles therein may be elevated. The elevated pressure causes the fluid 215 having the nanoparticles 210 suspended therein to diffuse through the interconnected interstitial spaces of the at least partially leached PCD body 124 toward the low pressure on the outside of the infiltrating vessel, thereby infiltrating the PCD body 124 with nanoparticles as they become trapped or otherwise stopped in the empty interstitial spaces of the PCD body 124. In embodiments, the pressure exerted on the fluid having nanoparticles suspended therein may range from about 0.102 MPa to about 350 MPa. The act 330 of causing at least a region of a PCD body to be occupied by nanoparticles may include elevating the pressure exerted on the fluid 215 having nanoparticles to a pressure and for a duration sufficient to achieve the desired depth and/or density of infiltration, by way of non-limiting example, at about 100 MPa for about 1 hour. Sufficient durations may include more than about 30 seconds, such as about 1 minute, about 3 minutes, about 5 minutes, about 10 minutes, about 30 minutes, about 1 hour, about 2 hours, about 24 hours, about 1 minute to about 1 hour, about 2 minutes to about 30 minutes, or less than 24 hours. Infiltration duration may be tailored according to infiltration pressure, nanoparticle size, fluid properties, PCD body density, desired infiltration depth, and combinations thereof. In such an embodiment, only a portion of the PCD body may be infiltrated (e.g., from the upper surface 130 to an intermediate depth d). In an embodiment, the act 330 of causing at least a region of a PCD body to be occupied by nanoparticles may include disposing the nanoparticles 210 in the fluid 215 for only a portion of the time the fluid 210 is infiltrated through the PCD body. In such an embodiment, the resulting PCD body 126′ (substantially as depicted in
In an embodiment of the act 340, the at least partially leached and infiltrated PCD body 126 may be bonded to a substrate. Bonding the at least partially leached and infiltrated PCD body 126 to a substrate 150 may include using a second HPHT process and/or brazing. In an embodiment, the at least partially leached and infiltrated PCD body 126 (substantially as depicted in any of
The PDCs disclosed herein may also be utilized in applications other than rotary drill bits. For example, the disclosed PDC embodiments may be used in thrust-bearing assemblies, radial bearing assemblies, wire-drawing dies, artificial joints, machining elements, PCD windows, and heat sinks.
In use, the bearing surfaces 612 of one of the thrust-bearing assemblies 602 bears against the opposing bearing surfaces 612 of the other one of the bearing assemblies 602. For example, one of the thrust-bearing assemblies 602 may be operably coupled to a shaft to rotate therewith and may be termed a “rotor.” The other one of the thrust-bearing assemblies 602 may be held stationary and may be termed a “stator.”
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 open ended and have the same meaning as the word “comprising” and variants thereof (e.g., “comprise” and “comprises”).
