Wear-resistant, superabrasive materials are traditionally utilized for a variety of mechanical applications. For example, polycrystalline diamond (“PCD”) materials are often used in drilling tools (e.g., cutting elements, gage trimmers, etc.), machining equipment, bearing apparatuses, wire-drawing machinery, and in other mechanical systems.
Conventional superabrasive materials have found utility as superabrasive cutting elements in rotary drill bits, such as roller cone drill bits and fixed-cutter drill bits. A conventional cutting element typically includes a superabrasive layer or table, such as a PCD table. The PCD table is formed and bonded to a substrate using an ultra-high pressure, ultra-high temperature (“HPHT”) process. The cutting element may be brazed, press-fit, or otherwise secured into a preformed pocket, socket, or other receptacle formed in the rotary drill bit. In another configuration, the substrate may be brazed or otherwise joined to an attachment member such as a stud or a cylindrical backing. Generally, a rotary drill bit may include one or more PCD cutting elements affixed to a bit body of the rotary drill bit.
Conventional superabrasive materials have also found utility as bearing elements in thrust bearing and radial bearing apparatuses. A conventional bearing element typically includes a superabrasive layer or table, such as a PCD table, bonded to a substrate. One or more bearing elements may be mounted to a bearing rotor or stator by press-fitting, brazing, or through other suitable methods of attachment. Typically, bearing elements mounted to a bearing rotor have superabrasive faces configured to contact corresponding superabrasive faces of bearing elements mounted to an adjacent bearing stator.
Superabrasive elements having a PCD table are typically fabricated by placing a cemented carbide substrate, such as a cobalt-cemented tungsten carbide substrate, into a container or cartridge with a volume of diamond particles positioned on a surface of the cemented carbide substrate. A number of such cartridges may be loaded into a HPHT press. The substrates and diamond particles may then be processed under HPHT conditions in the presence of a catalyst material that causes the diamond particles to bond to one another to form a diamond table having a matrix of bonded diamond grains. The catalyst material is often a metal-solvent catalyst, such as cobalt, nickel, and/or iron that facilitates intergrowth and bonding of the diamond grains.
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. In this example, the cobalt acts as a catalyst to facilitate the formation of bonded diamond grains. Optionally, a metal-solvent catalyst may be mixed with diamond particles prior to subjecting the diamond particles and substrate to the HPHT process.
The metal-solvent catalyst may dissolve carbon from the diamond particles and portions of the diamond particles that graphitize due to the high temperatures used in the HPHT process. The solubility of the stable diamond phase in the metal-solvent catalyst may be lower than that of the metastable graphite phase under HPHT conditions. As a result of the solubility difference, the graphite tends to dissolve into the metal-solvent catalyst and the diamond tends to deposit onto existing diamond particles to form diamond-to-diamond bonds. Accordingly, diamond grains may become mutually bonded to form a matrix of polycrystalline diamond, with interstitial regions defined between the bonded diamond grains being occupied by the metal-solvent catalyst.
In addition to dissolving diamond and graphite, the metal-solvent catalyst may also carry tungsten and/or tungsten carbide from the substrate into the PCD layer. Following HPHT sintering, the tungsten and/or tungsten carbide may remain in interstitial regions defined between the bonded diamond grains.
The presence of the solvent catalyst in the diamond table is believed to reduce the thermal stability of the diamond table 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 PCD table of a cutting element during drilling or cutting operations. The chipping or cracking in the PCD table may degrade the mechanical properties of the cutting element or lead to failure of the cutting element. Additionally, at high temperatures, diamond grains may undergo a chemical breakdown or back-conversion with the metal-solvent catalyst. At extremely high temperatures, portions of diamond grains may transform to carbon monoxide, carbon dioxide, graphite, or combinations thereof, thereby degrading the mechanical properties of the PCD material.
Accordingly, it may be desirable, for some applications, to remove a metal-solvent catalyst from a PCD material in situations where the PCD material may be exposed to high temperatures. Chemical leaching is often used to remove metal-solvent catalysts, such as cobalt, from regions of a PCD article that may experience high temperatures, such as regions adjacent to the working surfaces of the PCD article. Conventional chemical leaching techniques often involve the use of highly concentrated, toxic, and/or corrosive solutions, such as aqua regia and mixtures including hydrofluoric acid (HF), to dissolve and remove metal-solvent catalysts from polycrystalline diamond materials.
The instant disclosure is directed to a method of processing a polycrystalline diamond material. In some examples, the method may comprise leaching a metal-solvent catalyst from a polycrystalline diamond material by exposing at least a portion of the polycrystalline diamond material to a leaching solution. The leaching solution may include water. The leaching solution may also comprise a complexing agent configured to inhibit or prevent tungsten in the polycrystalline diamond material from oxidizing. The leaching solution may additionally comprise a mineral acid.
The complexing agent may comprise a chelating agent. In one example, the complexing agent may comprise a phosphate. In an additional embodiment, the complexing agent may comprise a weak acid having an acid dissociation constant (pKa) of between approximately −2 and 12. In various embodiments, the complexing agent may comprise at least one of phosphoric acid, citric acid, tartaric acid, oxalic acid, and ammonium chloride. The leaching solution may comprise the complexing agent at a molar concentration of between approximately 0.01 M and approximately 3 M. In some examples, the leaching solution may comprise the complexing agent at a molar concentration of approximately 0.125 M.
The metal-solvent catalyst may comprise at least one of cobalt, nickel, and iron. In an additional embodiment, the mineral acid may comprise at least one of nitric acid, hydrochloric acid, sulfuric acid, boric acid, and hydrofluoric acid. The leaching solution may comprise the mineral acid at a molar concentration of between approximately 0.1 M and approximately 3 M. In some examples, the leaching solution may comprise the mineral acid at a molar concentration of approximately 1.5 M. The complexing agent may be configured to form metal complexes with the tungsten. The metal complexes may be soluble in the leaching solution. Each of the metal complexes may comprise a tungsten atom and between 2 and 4 ligands.
The leaching solution may further comprise a peroxide. In one example, the polycrystalline diamond material may comprise bonded diamond grains. At least a portion of the tungsten and at least a portion of the metal-solvent catalyst may be disposed between the bonded diamond grains.
In an additional embodiment, the method may comprise exposing at least a portion of the polycrystalline diamond material and the leaching solution to a temperature of between approximately 25° C. and approximately 280° C. The method may additionally comprise exposing at least a portion of the polycrystalline diamond material and the leaching solution to a pressure of between approximately 20 bar and approximately 100 bar. In one example, the method may comprise exposing at least a portion of the polycrystalline diamond material and the leaching solution to at least one of an electric current, microwave radiation, and ultrasonic energy. The method may further comprise separating the polycrystalline diamond material from the leaching solution when the polycrystalline diamond material is substantially free of the metal-solvent catalyst to a depth of between approximately 100 μm and approximately 2500 μM.
In one embodiment, a method of processing a superabrasive element may comprise providing a superabrasive element. The superabrasive element may comprise a substrate and a polycrystalline diamond table bonded to the substrate. The polycrystalline diamond table may comprise tungsten and a metal-solvent catalyst. According to the method, at least a portion of the metal-solvent catalyst may be leached from the polycrystalline diamond table by exposing at least a portion of the polycrystalline diamond table to a leaching solution.
An additional method of processing a polycrystalline diamond material may comprise providing a polycrystalline diamond material. The polycrystalline diamond material may comprise bonded diamond grains, tungsten, and a metal-solvent catalyst. The method may further comprise forming metal complexes within the polycrystalline diamond material. The metal complexes may comprise at least a portion of the tungsten and a complexing agent. The method may also comprise dissolving at least a portion of the metal-solvent catalyst in a mineral acid solution. Additionally, the method may comprise extracting the dissolved metal-solvent catalyst from the polycrystalline diamond material.
Features from any of the above-mentioned embodiments may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features, and advantages will be more fully understood upon reading the following detailed description in conjunction with the accompanying drawings and claims.
The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, these drawings demonstrate and explain various principles of the instant disclosure.
Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the instant disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims.
The instant disclosure is directed to methods of processing superabrasive articles, such as superabrasive cutting elements, superabrasive bearings, and superabrasive discs. The superabrasive articles disclosed herein may be used in a variety of applications, such as drilling tools (e.g., compacts, cutting elements, gage trimmers, etc.), machining equipment, bearing apparatuses, wire-drawing machinery, and other apparatuses.
As used herein, the terms “superabrasive” and “superhard” may refer to materials exhibiting a hardness exceeding a hardness of tungsten carbide. For example, a superabrasive article may represent an article of manufacture, at least a portion of which may exhibit a hardness exceeding the hardness of tungsten carbide. Additionally, the term “solvent,” as used herein, may refer to a single solvent compound, a mixture of two or more solvent compounds, and/or a mixture of one or more solvent compounds and one or more dissolved compounds. The term “molar concentration,” as used herein, may refer to a concentration in units of mol/L at a temperature of approximately 25° C. For example, a solution comprising solute A at a molar concentration of 1 M may comprise 1 mol of solute A per liter of solution. Moreover, the word “cutting” may refer broadly to machining processes, drilling processes, boring processes, or any other material removal process utilizing a cutting element.
Substrate 12 may comprise any suitable material on which table 14 may be formed. In at least one embodiment, substrate 12 may comprise a cemented carbide material, such as a cobalt-cemented tungsten carbide material or any other suitable material. In some embodiments, substrate 12 may include a suitable metal-solvent catalyst material, such as, for example, cobalt, nickel, iron, and/or alloys thereof. Generally, substrate 12 may include any suitable material including, without limitation, cemented carbides such as titanium carbide, niobium carbide, tantalum carbide, vanadium carbide, and/or combinations of any of the preceding carbides cemented with iron, nickel, cobalt, and/or alloys thereof.
Table 14 may be formed of any suitable superabrasive and/or superhard material or combination of materials, including, for example PCD. According to additional embodiments, table 14 may comprise cubic boron nitride, silicon carbide, diamond, and/or mixtures or composites including one or more of the foregoing materials.
Table 14 may be formed using any suitable technique. For example, table 14 may comprise a PCD layer formed by subjecting a plurality of diamond particles (e.g., diamond particles having an average particle size between approximately 0.5 μm and approximately 150 μm) to a HPHT sintering process in the presence of a metal-solvent catalyst, such as cobalt, nickel, iron, and/or any other suitable group VIII element. During a HPHT sintering process, adjacent diamond grains in a mass of diamond particles may become bonded to one another, forming a PCD table comprising bonded diamond grains. In one example, diamond grains in table 14 may have an average grain size of approximately 20 μm or less. Additionally, during a HPHT sintering process, diamond grains may become bonded to an adjacent substrate 12 at interface 26.
According to various embodiments, table 14 may be formed by placing diamond particles adjacent to a substrate 12 comprising cemented tungsten carbide. The resulting sintered PCD layer may include tungsten and/or tungsten carbide. For example, tungsten and/or tungsten carbide may be swept into the PCD layer from substrate 12 during HPHT sintering. In some examples, a liquefied metal-solvent catalyst from substrate 12 (e.g., cobalt from a cobalt-cemented tungsten carbide substrate) may dissolve and/or carry tungsten and/or tungsten carbide from substrate 12 into a diamond mass used to form table 14 during HPHT sintering. In additional examples, tungsten and/or tungsten carbide particles may be intentionally mixed with diamond particles prior to forming table 14.
According to various embodiments, materials may be deposited in interstitial regions during processing of superabrasive table 14. For example, material components of substrate 12 may migrate into a mass of diamond particles used to form a superabrasive table 14 during HPHT sintering. As the mass of diamond particles is sintered, a metal-solvent catalyst may melt and flow from substrate 12 into the mass of diamond particles. As the metal-solvent flows into superabrasive table 14, it may dissolve and/or carry additional materials, such as tungsten and/or tungsten carbide, from substrate 12 into the mass of diamond particles. As the metal-solvent catalyst flows into the mass of diamond particles, the metal-solvent catalyst, and any dissolved and/or undissolved materials, may at least partially fill spaces between the diamond particles. The metal-solvent catalyst may facilitate bonding of adjacent diamond particles to form a PCD layer. Following sintering, any materials, such as, for example, the metal-solvent catalyst, tungsten, and/or tungsten carbide, may remain in interstitial regions within superabrasive table 14.
To improve the performance and heat resistance of a surface of superabrasive table 14, at least a portion of a metal-solvent catalyst, such as cobalt, may be removed from at least a portion of superabrasive table 14. Additionally, tungsten and/or tungsten carbide may be removed from at least a portion of superabrasive table 14. A metal-solvent catalyst, as well as other materials, may be removed from superabrasive table 14 using any suitable means, without limitation.
For example, chemical leaching may be used to remove a metal-solvent catalyst from superabrasive table 14 up to a depth D from a surface of superabrasive table 14, as illustrated in
Following leaching, superabrasive table 14 may comprise a first volume 30 that is substantially free of a metal-solvent catalyst. However, small amounts of catalyst may remain within interstices that are inaccessible to the leaching process. First volume 30 may extend from one or more surfaces of superabrasive table 14 (e.g., superabrasive face 20, superabrasive side surface 22, and/or superabrasive edge 24) to a depth D from the one or more surfaces. First volume 30 may be located adjacent one or more surfaces of superabrasive table 14.
Following leaching, superabrasive table may also comprise a second volume 31 that contains a metal-solvent catalyst. An amount of metal-solvent catalyst in second volume 31 may be substantially the same prior to and following leaching. In various embodiments, second volume 31 may be remote from one or more exposed surfaces of superabrasive table 14. In various embodiments, an amount of metal-solvent catalyst in first volume 30 and/or second volume 31 may vary at different depths in superabrasive table 14.
In at least one embodiment, superabrasive table 14 may include a transition region 29 between first volume 30 and second volume 31. Transition region 29 may include amounts of metal-solvent catalyst varying between an amount of metal-solvent catalyst in first volume 30 and an amount of metal-solvent catalyst in second volume 31. In various examples, transition region 29 may comprise a relatively narrow region between first volume 30 and second volume 31.
In at least one example, as shown in
Interstitial material 38 may be disposed in at least some of interstitial regions 34. Interstitial material 38 may comprise any suitable material, such as, for example, a metal-solvent catalyst, tungsten, and/or tungsten carbide. As shown in
In some examples, interstitial material 38 may be removed from table 14 to a depth that improves the performance and heat resistance of a surface of superabrasive table 14 to a desired degree. In some embodiments, interstitial material 38 may be removed from superabrasive table 14 to a practical limit. In order to remove interstitial material 38 from superabrasive table 14 to a depth beyond the practical limit, for example, significantly more time, temperature, and/or pressure may be required. In some embodiments, interstitial material 38 may be removed from superabrasive table 14 to a practical limit where interstitial material remains in at least a portion of superabrasive table 14. In various embodiments, superabrasive table 14 may be fully leached so that interstitial material 38 is substantially removed from a substantial portion of superabrasive table 14.
In at least one embodiment, interstitial material 38 may be leached from a superabrasive material, such as a PCD material in superabrasive table 14, by exposing the superabrasive material to a suitable leaching solution. Interstitial material 38 may include a metal-solvent catalyst, such as cobalt. Relatively less concentrated and/or corrosive solutions may be inhibited from leaching a PCD article to a sufficient depth due to the formation of passive tungsten oxide films in the PCD material as tungsten in the PCD material oxidizes. Oxygen present in various solutions may facilitate the formation of tungsten oxides, examples of which include WO2, W2O5, and WO3. The tungsten oxide films may inhibit dissolution of metal-solvent catalysts present in PCD materials, potentially slowing and hindering leaching of the PCD materials. Additionally, the tungsten oxide films may form a barrier that inhibits penetration of solutions beyond a certain depth into the PCD materials.
A suitable leaching solution may inhibit or prevent formation of oxide compounds, such as tungsten oxides, thereby potentially facilitating leaching of PCD materials. According to at least one embodiment, a leaching solution may comprise a solvent, a complexing agent, and a mineral acid. The superabrasive material may be exposed to such a leaching solution in any suitable manner, including, for example, by immersing at least a portion of the superabrasive material in the leaching solution.
The solvent in such a leaching solution may comprise water and/or any other suitable solvent, without limitation. In additional embodiments, the leaching solution may also include a peroxide, such as hydrogen peroxide.
The leaching solution may comprise a mineral acid suitable for increasing the solubility of a metal-solvent catalyst with respect to the leaching solution. The mineral acid may be selected for its ability to attack and/or dissolve the metal-solvent catalyst. The leaching solution may then carry the dissolved metal-solvent catalyst out of a PCD material comprising the metal-solvent catalyst. In some examples, a suitable mineral acid may be configured to increase the solubility of the cobalt in the leaching mixture, thereby facilitating leaching of cobalt from a superabrasive material using the leaching mixture. In additional examples, a mineral acid may be configured to increase the solubility of iron and/or nickel in the leaching mixture.
In various embodiments, nitric acid may be used as a mineral acid in the leaching solution. In some embodiments, a mineral acid, such as nitric acid, may also react with amorphous carbon present in interstitial regions 34 between diamond grains 32 in a superabrasive table 14 comprising a PCD material. Additional examples of suitable mineral acids may include, for example, hydrochloric acid, sulfuric acid, boric acid, hydrofluoric acid, and/or any combination of the foregoing mineral acids.
A mineral acid may be present in the leaching solution at a molar concentration of between approximately 0.1 M and approximately 3 M. In some examples, a mineral acid may be present in the leaching solution at a molar concentration of between approximately 1 M and approximately 2 M. In at least one example, a mineral acid may be present in the leaching solution at a molar concentration of approximately 1.5 M.
The leaching solution may additionally comprise a complexing agent dissolved in the solvent. The complexing agent may comprise a compound suitable for forming metal complexes with tungsten and/or tungsten carbide. The complexing agent may form metal complexes with tungsten and/or tungsten carbide present in a superabrasive material, thereby inhibiting or preventing the formation and build up of tungsten oxides, such as WO2, W2O5, and WO3, in the superabrasive material.
In at least one embodiment, metal complexes formed using the complexing agent may comprise a tungsten atom and between two and four ligands. For example, the complexing agent may comprise phosphoric acid. The phosphoric acid may at least partially dissociate in the leaching solution into various phosphate ions, such as, for example, dihydrogen phosphate, hydrogen phosphate, and/or orthophosphate. The phosphate ions may act as ligands in the metal complexes. In at least one embodiment, phosphate ligands may bond with a tungsten atom to form a metal complex comprising the tungsten atom and between two and four phosphate ligands surrounding the tungsten atom. The metal complexes may at least partially passivate the tungsten atom, inhibiting oxidation of the tungsten atom. Accordingly, the metal complexes may inhibit the formation of tungsten oxide films.
Metal complexes formed between the complexing agent and tungsten and/or tungsten carbide may be soluble in the leaching solution, thereby enabling the metal complexes to be easily removed from the superabrasive material. Accordingly, the complexing agent may facilitate the removal of tungsten and/or tungsten carbide from a leached portion of a superabrasive material, thereby reducing the amount of residual tungsten, tungsten carbide, and/or tungsten oxide present in a leached region of the superabrasive material. The complexing agent may also facilitate removal of additional metal compounds that may be present in the superabrasive material.
By inhibiting the formation and build up of tungsten oxides in a superabrasive material, the complexing agent may enable the leaching solution to dissolve and remove a metal-solvent catalyst from a greater portion of a superabrasive material in comparison with leaching solutions that do not include a complexing agent. Additionally, the complexing agent may enable a metal-solvent catalyst to be removed from a greater portion of a superabrasive material in a relatively shorter period of time. The complexing agent may also enable a metal-solvent catalyst to be leached from a superabrasive material using a less corrosive acid solution in comparison with conventional leaching solutions. Further, the leaching solution comprising the complexing agent may provide more uniform leaching of the superabrasive material.
According to at least one embodiment, the complexing agent may comprise a chelating agent. In at least one embodiment, the complexing agent may comprise a phosphate. Additionally, the complexing agent may comprise a weak acid having an acid dissociation constant (pKa) of between approximately −2 and 12. In one example, phosphoric acid may be used as the complexing agent. Additional examples of suitable compounds that may be used as complexing agents include, without limitation, citric acid, tartaric acid, oxalic acid, ammonium chloride, and/or any combination of the foregoing.
A complexing agent may be present in the leaching solution at a molar concentration of between approximately 0.01 M and approximately 3 M. In some examples, a complexing agent may be present in the leaching solution at a molar concentration of between approximately 0.05 M and approximately 0.5 M. In at least one example, a complexing agent may be present in the leaching solution at a molar concentration of approximately 0.125M.
According to various embodiments, a superabrasive material may be exposed to the leaching solution at an elevated temperature and/or pressure. Exposing the superabrasive material to an elevated temperature and/or pressure during leaching may increase the depth to which the superabrasive material may be leached. Additionally, exposing the superabrasive material to an elevated temperature and/or pressure during leaching may decrease an amount of time required to leach the superabrasive material to a desired degree.
In various examples, at least a portion of a superabrasive material and the leaching solution may be exposed to a temperature of between approximately 25° C. and approximately 280° C. during leaching. According to additional embodiments, at least a portion of a superabrasive material and the leaching solution may be exposed to a temperature of between approximately 60° C. and approximately 240° C. during leaching. A leaching solution comprising a relatively higher amount of hydrogen peroxide may be exposed to a temperature of approximately 80° C. or less.
In various embodiments, at least a portion of a superabrasive material and a leaching solution may be exposed to a pressure of between approximately 0 bar and approximately 100 bar during leaching. In additional embodiments, at least a portion of a superabrasive material and a leaching solution may be exposed to a pressure of between approximately 20 bar and approximately 80 bar during leaching. In at least one example, at least a portion of a superabrasive material and a leaching solution may be exposed to a pressure of approximately 50 bar during leaching.
According to additional embodiments, at least a portion of a superabrasive material and a leaching solution may be exposed to at least one of an electric current, microwave radiation, and/or ultrasonic energy. By exposing at least a portion of a superabrasive material to an electric current, microwave radiation, and/or ultrasonic energy as the superabrasive material is exposed to a leaching solution, the rate at which the superabrasive material is leached may be increased.
As illustrated in
At least one cutting element 58 may be coupled to bit body 44. For example, as shown in
Circumferentially adjacent blades 46 may define so-called junk slots 54 therebetween. Junk slots 54 may be configured to channel debris, such as rock or formation cuttings, away from cutting elements 58 during drilling. Rotary drill bit 42 may also include a plurality of nozzle cavities 56 for communicating drilling fluid from the interior of rotary drill bit 42 to cutting elements 58.
The superabrasive elements and discs disclosed herein may also be utilized in applications other than cutting technology. For example, embodiments of superabrasive elements disclosed herein may also form all or part of heat sinks, wire dies, bearing elements, cutting elements, cutting inserts (e.g., on a roller cone type drill bit), machining inserts, or any other article of manufacture as known in the art. Thus, superabrasive elements and discs, as disclosed herein, may be employed in any suitable article of manufacture that includes a superabrasive element, disc, or layer. Other examples of articles of manufacture that may incorporate superabrasive elements as disclosed herein may be found in U.S. Pat. Nos. 4,811,801; 4,268,276; 4,468,138; 4,738,322; 4,913,247; 5,016,718; 5,092,687; 5,120,327; 5,135,061; 5,154,245; 5,460,233; 5,544,713; and 6,793,681, the disclosure of each of which is incorporated herein, in its entirety, by this reference.
In additional embodiments, a rotor and a stator, such as a rotor and a stator used in a thrust bearing apparatus, may each include at least one superabrasive element according to the embodiments disclosed herein. For an example, U.S. Pat. Nos. 4,410,054; 4,560,014; 5,364,192; 5,368,398; and 5,480,233, the disclosure of each of which is incorporated herein, in its entirety, by this reference, disclose subterranean drilling systems that include bearing apparatuses utilizing superabrasive elements as disclosed herein.
Each support ring 68 may include a plurality of recesses 69 configured to receive corresponding bearing elements 70. Each bearing element 70 may be mounted to a corresponding support ring 68 within a corresponding recess 69 by brazing, welding, press-fitting, using fasteners, or any another suitable mounting technique, without limitation. One or more of bearing elements 70 may be configured in accordance with any of the disclosed superabrasive element embodiments. For example, each bearing element 70 may include a substrate 72 and a superabrasive table 74 comprising a PCD material. Each superabrasive table 74 may form a bearing surface 76.
Bearing surfaces 76 of one bearing assembly 66 may bear against opposing bearing surfaces 76 of a corresponding bearing assembly 66 in thrust-bearing apparatus 64, as illustrated in
Inner race 80 may be positioned generally within outer race 82. Thus, inner race 80 and outer race 82 may be configured such that bearing surfaces 85 defined by bearing elements 84 and bearing surfaces 87 defined by bearing elements 86 may at least partially contact one another and move relative to one another as inner race 80 and outer race 82 rotate relative to each other. According to various embodiments, thrust-bearing apparatus 64 and/or radial bearing apparatus 78 may be incorporated into a subterranean drilling system.
The thrust-bearing apparatus 64 shown in
A first thrust-bearing assembly 66 in thrust-bearing apparatus 64 may be configured as a rotor that is attached to output shaft 94 and a second thrust-bearing assembly 66 in thrust-bearing apparatus 64 may be configured as a stator. During a drilling operation using subterranean drilling system 88, the rotor may rotate in conjunction with output shaft 94 and the stator may remain substantially stationary relative to the rotor.
According to various embodiments, drilling fluid may be circulated through downhole drilling motor 92 to generate torque and effect rotation of output shaft 94 and rotary drill bit 96 attached thereto so that a borehole may be drilled. A portion of the drilling fluid may also be used to lubricate opposing bearing surfaces of bearing elements 70 on thrust-bearing assemblies 66.
The leaching solution may include a solvent, a complexing agent, and a mineral acid. According to some examples, the solvent may comprise water. Additionally, the complexing agent may be configured to inhibit tungsten in the polycrystalline diamond material from oxidizing. Each of the complexing agent and the mineral acid may be dissolved in the solvent. The polycrystalline diamond material may be exposed to the leaching solution in any suitable manner, such as, for example, by submerging at least a portion of the polycrystalline diamond material in the leaching solution.
A polycrystalline diamond material may comprise at least a portion of any suitable polycrystalline diamond article. For example, the polycrystalline material may comprise a PCD table attached to a tungsten carbide substrate in a superabrasive element or a superabrasive disc (e.g., superabrasive element 10 and superabrasive disc 28 in
At least a portion of the polycrystalline diamond and the leaching solution material may be exposed to a temperature of between approximately 25° C. and approximately 280° C. (step 114). Additionally, at least a portion of the polycrystalline diamond material and the leaching solution may be exposed to a pressure of between approximately 20 bar and approximately 100 bar (step 116).
When the polycrystalline diamond material is substantially free of the metal-solvent catalyst to a depth of between approximately 100 μm and approximately 2500 μm, the polycrystalline diamond material may be separated from the leaching solution (step 118). For example, a polycrystalline diamond material that is submerged in a leaching solution may be removed from the leaching solution. Additionally, the leaching solution may be at least partially washed from the polycrystalline diamond material.
At least a portion of the metal-solvent catalyst may be leached from the polycrystalline diamond table by exposing at least a portion of the polycrystalline diamond table to a leaching solution (step 124). The leaching solution may include a solvent, a complexing agent, and a mineral acid.
Metal complexes may be formed within the polycrystalline diamond material (step 134). The metal complexes may include at least a portion of the tungsten from the polycrystalline diamond material and a complexing agent. The tungsten may be present in the form of elemental tungsten and/or tungsten carbide.
At least a portion of the metal-solvent catalyst may be dissolved in a mineral acid solution (step 136). The dissolved metal-solvent catalyst may then be extracted from the polycrystalline diamond material (step 138). For example, the metal-solvent catalyst dissolved in the mineral acid solution may be transported away from the polycrystalline diamond material by the mineral acid solution.
The following examples set forth various methods used to form superabrasive elements as disclosed herein. The following examples provide further detail in connection with the specific embodiments described above.
Cutting elements, each comprising a PCD table attached to a tungsten carbide substrate, were formed by HPHT sintering diamond particles having an average grain size of about 10 μm in the presence of cobalt. The sintered-polycrystalline-diamond tables included cobalt and tungsten within the interstitial regions between the bonded diamond grains.
The PCD tables were leached using a solution having a molar concentration of 1.5 M nitric acid and 0.125 M phosphoric acid. The PCD tables were leached at a temperature of 60° C. and atmospheric pressure for between 1 and 5 days. Following leaching, leached depths of the PCD tables were determined for various portions of the PCD tables, including leached depths measured from the cutting faces, side surfaces, and chamfered cutting edges of the PCD tables.
Following 1 day of leaching, a first PCD table included leached depths of 81-118 μm and a second PCD table included leached depths of 107-133 μm.
Following 2 days of leaching, a first PCD table included leached depths of 145-169 μm and a second PCD table included leached depths of 140-179 μm.
Following 3 days of leaching, a first PCD table included leached depths of 199-234 μm and a second PCD table included leached depths of 190-215 μm.
Following 4 days of leaching, a first PCD table included leached depths of 215-259 μm and a second PCD table included leached depths of 198-245 μm.
Following 5 days of leaching, a first PCD table included leached depths of 237-303 μm and a second PCD table included leached depths of 238-286 μm.
Cutting elements, each comprising a PCD table attached to a tungsten carbide substrate, were formed by HPHT sintering diamond particles having an average grain size of about 10 μm in the presence of cobalt. The sintered-polycrystalline-diamond tables included cobalt and tungsten within the interstitial regions between the bonded diamond grains.
The PCD tables were leached using a solution having a molar concentration of 1.5 M nitric acid and 0.125 M phosphoric acid. The PCD tables were leached at a temperature of 75° C. and atmospheric pressure for between 1 and 2 days. Following leaching, leached depths of the PCD tables were determined for various portions of the PCD tables, including leached depths measured from the cutting faces, side surfaces, and chamfered cutting edges of the PCD tables.
Following 1 day of leaching, a PCD table included leached depths of 105-156 μm. Following 2 days of leaching, a PCD table included leached depths of 193-238 μm.
A cutting element comprising a PCD table attached to a tungsten carbide substrate was formed by HPHT sintering diamond particles having an average grain size of about 10 μm in the presence of cobalt. The sintered-polycrystalline-diamond table included cobalt and tungsten within the interstitial regions between the bonded diamond grains.
The PCD table was leached using a solution having a molar concentration of 1.5 M nitric acid and 0.125 M phosphoric acid. The PCD table was leached at a temperature of 120° C. and atmospheric pressure for 5 days.
Following leaching, leached depths of the PCD table were determined for various portions of the PCD table, including leached depths measured from the table cutting face, side surfaces, and chamfered cutting edges of the PCD table. Following 5 days of leaching, the PCD table included leached depths of 160-585 μm.
The preceding description has been provided to enable others skilled the art to best utilize various aspects of the exemplary embodiments described herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the instant disclosure. It is desired that the embodiments described herein be considered in all respects illustrative and not restrictive and that reference be made to the appended claims and their equivalents for determining the scope of the instant disclosure.
Unless otherwise noted, the terms “a” or “an,” as used in the specification and claims, are to be construed as meaning “at least one of.” In addition, for ease of use, the words “including” and “having,” as used in the specification and claims, are interchangeable with and have the same meaning as the word “comprising.”
This application is a continuation of U.S. patent application Ser. No. 12/419,191 filed 6 Apr. 2009, now U.S. Pat. No. 7,972,395, which is hereby incorporated by reference in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
3136615 | Bovenkerk et al. | Jun 1964 | A |
3141746 | De Lai et al. | Jul 1964 | A |
3233988 | Wentorf et al. | Feb 1966 | A |
3745623 | Wentorf, Jr. et al. | Jul 1973 | A |
4108614 | Mitchell | Aug 1978 | A |
4151686 | Lee et al. | May 1979 | A |
4224380 | Bovenkerk et al. | Sep 1980 | A |
4255165 | Dennis et al. | Mar 1981 | A |
4268276 | Bovenkerk | May 1981 | A |
4288248 | Bovenkerk et al. | Sep 1981 | A |
4303442 | Hara et al. | Dec 1981 | A |
4311490 | Bovenkerk et al. | Jan 1982 | A |
4373593 | Phaal et al. | Feb 1983 | A |
4387287 | Marazzi | Jun 1983 | A |
4412980 | Tsuji et al. | Nov 1983 | A |
4481016 | Campbell et al. | Nov 1984 | A |
4486286 | Lewin et al. | Dec 1984 | A |
4504519 | Zelez | Mar 1985 | A |
4522633 | Dyer | Jun 1985 | A |
4525179 | Gigl | Jun 1985 | A |
4534773 | Phaal et al. | Aug 1985 | A |
4556403 | Almond et al. | Dec 1985 | A |
4560014 | Geczy | Dec 1985 | A |
4570726 | Hall | Feb 1986 | A |
4572722 | Dyer | Feb 1986 | A |
4604106 | Hall | Aug 1986 | A |
4605343 | Hibbs, Jr. et al. | Aug 1986 | A |
4606738 | Hayden | Aug 1986 | A |
4621031 | Scruggs | Nov 1986 | A |
4636253 | Nakai et al. | Jan 1987 | A |
4645977 | Kurokawa et al. | Feb 1987 | A |
4662348 | Hall et al. | May 1987 | A |
4664705 | Horton et al. | May 1987 | A |
4670025 | Pipkin | Jun 1987 | A |
4707384 | Schachner et al. | Nov 1987 | A |
4726718 | Meskin et al. | Feb 1988 | A |
4731296 | Kikuchi et al. | Mar 1988 | A |
4766040 | Hillert et al. | Aug 1988 | A |
4776861 | Frushour | Oct 1988 | A |
4784023 | Dennis | Nov 1988 | A |
4792001 | Zijsling | Dec 1988 | A |
4793828 | Burnand | Dec 1988 | A |
4797241 | Peterson et al. | Jan 1989 | A |
4802539 | Hall et al. | Feb 1989 | A |
4807402 | Rai | Feb 1989 | A |
4828582 | Frushour | May 1989 | A |
4844185 | Newton, Jr. et al. | Jul 1989 | A |
4854405 | Stroud | Aug 1989 | A |
4861350 | Phaal et al. | Aug 1989 | A |
4871377 | Frushour | Oct 1989 | A |
4899922 | Slutz et al. | Feb 1990 | A |
4919220 | Fuller et al. | Apr 1990 | A |
4931068 | Dismukes et al. | Jun 1990 | A |
4940180 | Martell | Jul 1990 | A |
4943488 | Sung et al. | Jul 1990 | A |
4944772 | Cho | Jul 1990 | A |
4976324 | Tibbitts | Dec 1990 | A |
5011514 | Cho et al. | Apr 1991 | A |
5027912 | Juergens | Jul 1991 | A |
5030276 | Sung et al. | Jul 1991 | A |
5092687 | Hall | Mar 1992 | A |
5096465 | Chen et al. | Mar 1992 | A |
5116568 | Sung et al. | May 1992 | A |
5127923 | Bunting et al. | Jul 1992 | A |
5135061 | Newton, Jr. | Aug 1992 | A |
5176720 | Martell et al. | Jan 1993 | A |
5186725 | Martell et al. | Feb 1993 | A |
5199832 | Meskin et al. | Apr 1993 | A |
5205684 | Meskin et al. | Apr 1993 | A |
5213248 | Horton et al. | May 1993 | A |
5238074 | Tibbitts et al. | Aug 1993 | A |
5264283 | Waldenstrom et al. | Nov 1993 | A |
5337844 | Tibbitts | Aug 1994 | A |
5355969 | Hardy et al. | Oct 1994 | A |
5370195 | Keshavan et al. | Dec 1994 | A |
5379853 | Lockwood et al. | Jan 1995 | A |
5439492 | Anthony et al. | Aug 1995 | A |
5464068 | Najafi-Sani | Nov 1995 | A |
5468268 | Tank et al. | Nov 1995 | A |
5496638 | Waldenstrom et al. | Mar 1996 | A |
5496639 | Connell et al. | Mar 1996 | A |
5505748 | Tank et al. | Apr 1996 | A |
5510193 | Cerutti et al. | Apr 1996 | A |
5523121 | Anthony et al. | Jun 1996 | A |
5524719 | Dennis | Jun 1996 | A |
5560716 | Tank et al. | Oct 1996 | A |
5607024 | Keith et al. | Mar 1997 | A |
5620302 | Garrison et al. | Apr 1997 | A |
5620382 | Cho et al. | Apr 1997 | A |
5624068 | Waldenstrom et al. | Apr 1997 | A |
5645617 | Frushour | Jul 1997 | A |
5667028 | Truax et al. | Sep 1997 | A |
5718948 | Ederyd et al. | Feb 1998 | A |
5722497 | Gum et al. | Mar 1998 | A |
5722499 | Nguyen et al. | Mar 1998 | A |
5759216 | Kanada et al. | Jun 1998 | A |
5776615 | Wong et al. | Jul 1998 | A |
5833021 | Mensa-Wilmot et al. | Nov 1998 | A |
5875862 | Jurewicz et al. | Mar 1999 | A |
5897942 | Karner et al. | Apr 1999 | A |
5954147 | Overstreet et al. | Sep 1999 | A |
5979578 | Packer | Nov 1999 | A |
6009963 | Chaves et al. | Jan 2000 | A |
6063333 | Dennis | May 2000 | A |
6123612 | Goers | Sep 2000 | A |
6126741 | Jones et al. | Oct 2000 | A |
6193001 | Eyre et al. | Feb 2001 | B1 |
6234261 | Evans et al. | May 2001 | B1 |
6248447 | Griffin et al. | Jun 2001 | B1 |
6269894 | Griffin | Aug 2001 | B1 |
6290726 | Pope et al. | Sep 2001 | B1 |
6315065 | Yong et al. | Nov 2001 | B1 |
6332503 | Pessier et al. | Dec 2001 | B1 |
6344149 | Oles | Feb 2002 | B1 |
6367568 | Steinke et al. | Apr 2002 | B2 |
6410085 | Griffin et al. | Jun 2002 | B1 |
6435058 | Matthias et al. | Aug 2002 | B1 |
6481511 | Matthias et al. | Nov 2002 | B2 |
6528159 | Kuroda et al. | Mar 2003 | B1 |
6544308 | Griffin et al. | Apr 2003 | B2 |
6550556 | Middlemiss et al. | Apr 2003 | B2 |
6562462 | Griffin et al. | May 2003 | B2 |
6585064 | Griffin et al. | Jul 2003 | B2 |
6589640 | Griffin et al. | Jul 2003 | B2 |
6592985 | Griffin et al. | Jul 2003 | B2 |
6601662 | Matthias et al. | Aug 2003 | B2 |
6739214 | Griffin et al. | May 2004 | B2 |
6749033 | Griffin et al. | Jun 2004 | B2 |
6797326 | Griffin et al. | Sep 2004 | B2 |
6861098 | Griffin et al. | Mar 2005 | B2 |
6861137 | Hughes et al. | Mar 2005 | B2 |
6878447 | Griffin et al. | Apr 2005 | B2 |
6892836 | Eyre et al. | May 2005 | B1 |
6904984 | Estes et al. | Jun 2005 | B1 |
6935444 | Lund et al. | Aug 2005 | B2 |
6962214 | Hughes et al. | Nov 2005 | B2 |
6991049 | Eyre et al. | Jan 2006 | B2 |
7350601 | Belnap et al. | Apr 2008 | B2 |
7377341 | Middlemiss et al. | May 2008 | B2 |
7506698 | Eyre et al. | Mar 2009 | B2 |
7568534 | Griffin et al. | Aug 2009 | B2 |
20050115744 | Griffin et al. | Jun 2005 | A1 |
20050129950 | Griffin et al. | Jun 2005 | A1 |
20050139397 | Achilles et al. | Jun 2005 | A1 |
20050230156 | Belnap et al. | Oct 2005 | A1 |
20050263328 | Middlemiss | Dec 2005 | A1 |
20060060390 | Eyre | Mar 2006 | A1 |
20060060391 | Eyre et al. | Mar 2006 | A1 |
20060086540 | Griffin et al. | Apr 2006 | A1 |
20060162969 | Belnap et al. | Jul 2006 | A1 |
20070039762 | Achilles | Feb 2007 | A1 |
20070169419 | Davis et al. | Jul 2007 | A1 |
20070181348 | Lancaster et al. | Aug 2007 | A1 |
20070187155 | Middlemiss | Aug 2007 | A1 |
20090152016 | Eyre et al. | Jun 2009 | A1 |
Number | Date | Country |
---|---|---|
0196777 | Oct 1986 | EP |
0300699 | Jan 1989 | EP |
0329954 | Aug 1989 | EP |
0500253 | Aug 1992 | EP |
0585631 | Mar 1994 | EP |
0595630 | May 1994 | EP |
0612868 | Aug 1994 | EP |
0617207 | Sep 1994 | EP |
0787820 | Aug 1997 | EP |
0860515 | Aug 1998 | EP |
1190791 | Mar 2002 | EP |
1349385 | Apr 1974 | GB |
2048927 | Dec 1980 | GB |
2268768 | Jan 1994 | GB |
2323398 | Sep 1998 | GB |
2418215 | Mar 2006 | GB |
2422394 | Jul 2006 | GB |
59-35066 | Feb 1984 | JP |
61-67740 | Oct 1984 | JP |
59-219500 | Dec 1984 | JP |
61-125739 | Jun 1986 | JP |
63-069971 | Sep 1986 | JP |
63-55161 | Aug 1987 | JP |
07-156003 | Nov 1993 | JP |
07-62468 | Mar 1995 | JP |
11-245103 | Sep 1999 | JP |
2000-087112 | Mar 2000 | JP |
2034937 | May 1995 | RU |
566439 | Jul 2000 | RU |
WO-9323204 | Nov 1993 | WO |
WO-9634131 | Oct 1996 | WO |
WO-0028106 | May 2000 | WO |
WO-2004040095 | May 2004 | WO |
WO-2004106003 | Dec 2004 | WO |
WO-2004106004 | Dec 2004 | WO |
Entry |
---|
Nakamura, T. et al; Study on the Heat Deterioration Mechanism of Sintered Diamond; Program and Abstracts of the 27th High Pressure Conference of Japan; Oct 13-15 1986; Sapporo. |
Hong, S. et al.; Dissolution Behavior of Fine Prticles of Diamond Under High Pressure Sintering Conditions; Jornal of Materials Science Letters 10; pp. 164-166; 1991. |
Number | Date | Country | |
---|---|---|---|
Parent | 12419191 | Apr 2009 | US |
Child | 13114599 | US |