(19)
(11)EP 2 449 203 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
27.09.2017 Bulletin 2017/39

(21)Application number: 10794807.7

(22)Date of filing:  02.07.2010
(51)Int. Cl.: 
E21B 10/46  (2006.01)
E21B 10/50  (2006.01)
B24D 3/10  (2006.01)
E21B 10/54  (2006.01)
B23K 35/36  (2006.01)
C22C 26/00  (2006.01)
(86)International application number:
PCT/US2010/040860
(87)International publication number:
WO 2011/003051 (06.01.2011 Gazette  2011/01)

(54)

HARDFACING MATERIALS INCLUDING PCD PARTICLES, WELDING RODS AND EARTH-BORING TOOLS INCLUDING SUCH MATERIALS, AND METHODS OF FORMING AND USING SAME

AUFSCHWEISSUNGSMATERIALIEN MIT PCD-PARTIKELN, SCHWEISSSTANGEN UND ERDBOHRWERKZEUGE MIT SOLCHEN MATERIALIEN SOWIE VERFAHREN ZU IHRER BILDUNG UND VERWENDUNG

MATERIAUX DE SURFAÇAGE COMPRENANT DES PARTICULES DE DIAMANT POLYCRISTALLIN (PCD), BAGUETTES DE SOUDURE ET OUTILS DE FORAGE COMPRENANT DE TELS MATERIAUX ET PROCEDES DE FABRICATION ET D'UTILISATION ASSOCIES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

(30)Priority: 02.07.2009 US 497420

(43)Date of publication of application:
09.05.2012 Bulletin 2012/19

(73)Proprietor: Baker Hughes Incorporated
Houston, TX 77210 (US)

(72)Inventors:
  • LYONS, Nicholas, J.
    The Woodlands TX 77380 (US)
  • SCOTT, Dan, E.
    The Woodlands TX 77380 (US)

(74)Representative: Jeffrey, Philip Michael 
Dehns St Bride's House
10 Salisbury Square London EC4Y 8JD
10 Salisbury Square London EC4Y 8JD (GB)


(56)References cited: : 
US-A- 4 738 322
US-A1- 2003 024 351
US-A1- 2008 048 484
US-A- 5 755 299
US-A1- 2004 025 443
US-A1- 2008 283 305
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] Embodiments of the present invention relate to materials that may be used to increase the wear-resistance of earth-boring tools and components of earth-boring tools used in the formation of wellbores, and to methods of forming and using such materials, tools, and components.

    BACKGROUND



    [0002] Wellbores are formed in subterranean formations for various purposes including, for example, extraction of oil and gas from subterranean formations and extraction of geothermal heat from subterranean formations. A wellbore may be formed in a subterranean formation using an earth-boring rotary drill bit. Different types of earth-boring rotary drill bits are known in the art including, for example, fixed-cutter drill bits (which are often referred to in the art as "drag" bits), roller cone drill bits (which are often referred to in the art as "rock" bits), diamond-impregnated bits, and hybrid bits (which may include, for example, both fixed cutters and roller cone cutters). The drill bit is rotated under an applied axial force, termed "weight-on-bit" (WOB) in the art, and advanced into the subterranean formation. As the drill bit rotates, the cutters or abrasive structures thereof cut, crush, shear, and/or abrade away the formation material to form the wellbore.

    [0003] The drill bit is coupled, either directly or indirectly, to an end of what is referred to in the art as a "drill string," which comprises a series of elongated tubular segments connected end-to-end that extends into the wellbore from the surface of the formation. Various tools and components, including the drill bit, may be coupled together at the distal end of the drill string at the bottom of the wellbore being drilled. This assembly of tools and components is referred to in the art as a "bottom hole assembly" (BHA).

    [0004] The drill bit may be rotated within the wellbore by rotating the drill string from the surface of the formation, or the drill bit may be rotated by coupling the drill bit to a downhole motor, which is also coupled to the drill string and disposed proximate the bottom of the wellbore. The downhole motor may comprise, for example, a hydraulic Moineau-type motor having a shaft, to which the drill bit is coupled. The shaft of the motor is rotated by pumping fluid (e.g., drilling mud or fluid) from the surface of the formation down through the center of the drill string, through the hydraulic motor, out from nozzles in the drill bit, and back up to the surface of the formation through the annular space between the outer surface of the drill string and the exposed surface of the formation within the wellbore.

    [0005] The materials of earth-boring tools need to be relatively hard and wear-resistant to efficiently remove formation material within a wellbore without undergoing excessive wear. Due to the extreme forces and stresses to which drill bits and other earth-boring tools are subjected during drilling and reaming operations, the materials of earth-boring tools must simultaneously exhibit relatively high fracture toughness. Materials that exhibit extremely high hardness, however, tend to be relatively brittle and do not exhibit high fracture toughness, while materials that exhibit high fracture toughness tend to be relatively soft and do not exhibit high hardness. As a result, a compromise must be made between hardness and fracture toughness when selecting materials for use in drill bits.

    [0006] In an effort to simultaneously improve both the hardness and fracture toughness of earth-boring drill bits, composite materials have been applied to the surfaces of drill bits that are subjected to abrasion, erosion, or to both abrasion and erosion. These composite materials are often referred to as "hardfacing" materials. Hardfacing materials typically include at least one phase that exhibits relatively high hardness and another phase that exhibits relatively high fracture toughness.

    [0007] For example, hardfacing materials often include tungsten carbide particles dispersed throughout a metal or metal alloy matrix material. The tungsten carbide particles are relatively hard compared to the matrix material, and the matrix material is relatively tough compared to the tungsten carbide particles.

    [0008] Tungsten carbide particles used in hardfacing materials may comprise one or more of cast tungsten carbide particles, sintered tungsten carbide particles, and macrocrystalline tungsten carbide particles. The tungsten carbide system includes two stoichiometric compounds, WC and W2C, with a continuous range of compositions therebetween. Cast tungsten carbide generally includes a eutectic mixture of the WC and W2C compounds. Sintered tungsten carbide particles include relatively smaller particles of WC bonded together by a matrix material. Cobalt and cobalt alloys are often used as matrix materials in sintered tungsten carbide particles. Sintered tungsten carbide particles can be formed by mixing together a first powder that includes the relatively smaller tungsten carbide particles and a second powder that includes cobalt particles. The powder mixture is formed in a "green" state. The green powder mixture then is sintered at a temperature near the melting temperature of the cobalt particles to form a matrix of cobalt material surrounding the tungsten carbide particles to form particles of sintered tungsten carbide. Finally, macrocrystalline tungsten carbide particles generally consist of single crystals of WC.

    [0009] Various techniques known in the art may be used to apply a hardfacing material to a surface of an earth-boring tool. For example, automated and manual welding processes may be used to apply hardfacing material to an earth-boring tool. In some manual processes, a welding rod that comprises the hardfacing material is provided, and a torch (e.g., an oxyacetylene torch or an arc-welding torch) is used to heat an end of the rod and, optionally, the surface of the tool to which the hardfacing is to be applied. The end of the rod is heated until at least the matrix material begins to melt. As the matrix material at the end of the rod begins to melt, the melting hardfacing material is applied to the surface of the tool. The hard particles dispersed within the matrix material are also applied to the surface with the molten matrix material. After application, the molten matrix material is allowed to cool and solidify.

    [0010] Such welding rods may comprise a substantially solid, cast rod of the hardfacing material, or they may comprise a hollow, cylindrical tube formed from the matrix material of the hardfacing material and filled with hard particles (e.g., tungsten carbide particles). In welding rods of the tubular configuration, at least one end of the hollow, cylindrical tube may be sealed. The sealed end of the tube then may be melted or welded onto the desired surface on the earth-boring tool. As the tube melts, the tungsten carbide particles within the hollow, cylindrical tube mix with the molten matrix material as it is deposited onto the surface of the tool. An alternative technique involves forming a cast rod of the hardfacing material.

    [0011] Flame spray processes are also used to apply hardfacing materials to earth-boring tools. In a flame spray process, a powder comprising the hard particles and particles of the matrix material is carried by a pressurized fluid (e.g., a pressurized gas) to a nozzle. The powder mixture is sprayed out from the nozzle and through a flame toward the surface of the tool to which the hardfacing is to be applied. The flame causes the particles of matrix material to at least partially melt. As the material is sprayed onto the tool, the molten matrix material cools and solidifies, and the hard particles become embedded in the matrix material to form the hardfacing on the surface of the tool.

    [0012] Various types of arc welding processes are known in the art and may be used to apply hardfacing to a surface of an earth-boring tool. For example, metal-inert gas (MIG) welding processes, tungsten-inert gas (TIG) welding processes, and plasma-transferred arc (PTA) welding processes may be used to apply hardfacing to a surface of an earth-boring tool.

    [0013] There remains a need in the art for abrasive, wear-resistant hardfacing materials that exhibit improved resistance to abrasion, erosion, or both abrasion and erosion.

    [0014] US 5755299 discloses hardfacing with coated diamond particles. US 4738322 discloses a polycrystalline diamond bearing system for a roller cone rock bit. US 2008/048484 discloses a shank for an attack tool.

    DISCLOSURE



    [0015] According to an aspect, there is provided an earth-boring tool as claimed in claim 1. According to another aspect, there is provided a method of hardfacing an earth-boring tool as claimed in claim 9.

    [0016] In some embodiments, the present invention includes hardfacing materials comprising particles of polycrystalline diamond material embedded within a matrix material. The particles of polycrystalline diamond material comprise a plurality of inter-bonded diamond grains.

    [0017] In additional embodiments, the present invention includes material compositions and structures, such as welding rods, that may be used to apply a hardfacing material to a surface of an earth-boring tool. The material compositions and structures include particles of polycrystalline diamond material comprising a plurality of inter-bonded diamond grains. For example, a welding rod may comprise an elongated, generally cylindrical body comprising a metal matrix material, and particles of polycrystalline diamond material carried by the elongated, generally cylindrical body.

    [0018] In additional embodiments, the present invention includes earth-boring tools that include a body, at least one cutting element on the body, and a hardfacing material on at least a portion of a surface of the body. The hardfacing material includes particles of polycrystalline diamond material embedded within a matrix material. The particles of polycrystalline diamond material include a plurality of inter-bonded diamond grains.

    [0019] In further embodiments, the present invention includes methods of forming a hardfacing material in which diamond grains are subjected to a temperature greater than about 1500°C and a pressure greater than about 5.0 gigapascals (GPa) to form diamond-to-diamond bonds between the diamond grains and form a polycrystalline diamond material. The polycrystalline diamond material is broken down to form particles of polycrystalline diamond material that include a plurality of inter-bonded diamond grains.

    [0020] Yet further embodiments of the present invention include methods of hardfacing an earth-boring tool in which particles of polycrystalline diamond material that include a plurality of inter-bonded diamond grains are bonded to a surface of an earth-boring tool using a metal matrix material.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0021] While the specification concludes with claims particularly pointing out and distinctly claiming that which is regarded as the present invention, various features and advantages of embodiments of the invention may be more readily ascertained from the following description of some embodiments invention when read in conjunction with the accompanying drawings, in which:

    FIG. 1 is a simplified drawing of an embodiment of a hardfacing material of the present invention;

    FIG. 2A is a simplified drawing of a hard particle of the hardfacing material of FIG. 1 that includes polycrystalline diamond material;

    FIG. 2B is a cross-sectional view of the hard particle shown in FIG. 2A taken along section line 2B-2B therein;

    FIG. 2C is a simplified sketch showing how the hard particle of FIGS. 2A and 2B may appear under magnification, and illustrates a plurality of inter-bonded diamond grains;

    FIG. 3 is a partially cut-away view of a cutting element that includes a layer of polycrystalline diamond material that may be used to form hard particles like that shown in FIGS. 2A-2C;

    FIG. 4 is a partially cut-away view of the layer of polycrystalline diamond material shown in FIG. 3 removed from a substrate on which the layer was previously disposed;

    FIG. 5 is a perspective view of an embodiment of a welding rod of the present invention that includes hard particles like that shown in FIGS. 2A-2C;

    FIG. 6A is a perspective view of another embodiment of a welding rod of the present invention that includes hard particles like that shown in FIGS. 2A-2C;

    FIG. 6B is a longitudinal cross-sectional view of the welding rod shown in FIG. 6A;

    FIG. 7 is a side view of an embodiment of a roller cone earth-boring rotary drill bit of the present invention that includes a hardfacing material like that shown in FIG. 1; and

    FIG. 8 is a perspective view of an embodiment of a fixed-cutter earth-boring rotary drill bit of the present invention that includes a hardfacing material like that shown in FIG. 1.


    MODE(S) FOR CARRYING OUT THE INVENTION



    [0022] The illustrations presented herein are not actual views of any particular drilling system, drilling tool assembly, or component of such an assembly, but are merely idealized representations which are employed to describe the present invention.

    [0023] As used herein, the term "polycrystalline diamond material" means and includes a volume of material that includes two or more grains (also referred to in the art as "crystals") bonded directly to one another at least partially by diamond-to-diamond bonds. In other words, polycrystalline diamond material is a material that includes two or more inter-bonded diamond grains.

    [0024] As used herein, the term "inter-bonded diamond grains" means grains that are directly bonded to one another at least partially by diamond-to-diamond bonds.

    [0025] FIG. 1 is a simplified drawing illustrating an embodiment of a hardfacing material 10 of the present invention. The hardfacing material 10 comprises a composite material that includes a discontinuous or "dispersed" phase 12 embedded within and dispersed throughout a continuous matrix phase 14. The discontinuous phase 12 exhibits a hardness higher than a hardness exhibited by the matrix phase 14, and the matrix phase 14 exhibits a fracture toughness higher than a fracture toughness exhibited by the discontinuous phase 12.

    [0026] The matrix phase 14 of the hardfacing material 10 may comprise a metal or metal alloy. By way of example and not limitation, the matrix phase 14 may comprise cobalt-based, iron-based, nickel-based, iron and nickel-based, cobalt and nickel-based, iron and cobalt-based, copper-based, and titanium-based alloys. The matrix phase 14 may also be selected from commercially pure elements such as cobalt, iron, nickel, copper, and titanium. In some embodiments, the matrix phase 14 may comprise a matrix or "binder" material having a melting point below about 1350°C, as disclosed in U.S. Patent Application Publication No. 2005/0247491 A1, filed April 28, 2008 and entitled "Earth-Boring Bits."

    [0027] The discontinuous phase 12 may comprise finite spatial volumes of polycrystalline diamond material that are dispersed throughout and embedded within the matrix phase 14. In some embodiments, the finite spatial volumes of the discontinuous phase 12 may be formed from and comprise particles of polycrystalline diamond (PCD) material, which are hereinafter referred to as PCD particles.

    [0028] The hardfacing material 10 optionally may also comprise an additional discontinuous phase 13 that includes at least one of a carbide material (e.g., tungsten carbide, titanium carbide, tantalum carbide, silicon carbide, etc.), a boride material (e.g., titanium boride), a nitride material (e.g., silicon nitride), and non-polycrystalline diamond grit.

    [0029] The hardfacing material 10 may be applied to surfaces of earth-boring tools using various methods. For example, automated and manual welding processes may be used to apply hardfacing material 10 to a surface of an earth-boring tool. Various types of arc welding processes may be used to apply hardfacing material 10 to a surface of an earth-boring tool. For example, metal-inert gas (MIG) welding processes, tungsten-inert gas (TIG) welding processes, and plasma-transferred arc (PTA) welding processes may be used to apply hardfacing material 10 to a surface of an earth-boring tool. Flame spray processes also may be used to apply hardfacing material 10 to surfaces of earth-boring tools.

    [0030] FIGS. 2A-2C illustrate an example of a PCD particle 16 that may be used in accordance with embodiments of the present invention to form the discontinuous phase 12 of the hardfacing material 10 of FIG. 1.

    [0031] Referring to FIG. 2A, the PCD particles 16 used to form the hardfacing material 10 (FIG. 1) may have irregular rough and jagged shapes in some embodiments of the present invention. In other words, the PCD particles 16 may comprise relatively sharp edges and corners. In additional embodiments of the present invention, the PCD particles 16 may be relatively smooth and rounded. Relatively rough and jagged PCD particles 16 may be processed to form relatively smooth and rounded PCD particles using processes known in the art, such as, for example, tumbling processes, jet blending processes, and etching processes. Depending on the particular application for which the hardfacing material 10 (FIG. 1) is to be used, either relatively rough and jagged PCD particles 16, as shown in FIG. 2A, or relatively smooth and rounded PCD particles may exhibit more desirable physical characteristics and performance.

    [0032] FIG. 2B is a cross-sectional view of the PCD particle 16 of FIG. 2A taken along section line 2B-2B therein. As shown in FIG. 2B, in some embodiments of the present invention, the PCD particles 16 used to form the discontinuous phase 12 of the hardfacing material 10 (FIG. 1) may be at least substantially planar. In other embodiments, however, the PCD particles 16 may not be planar, and may be generally spherical, cubical, etc.

    [0033] In embodiments in which the PCD particles 16 are at least substantially planar as shown in FIGS. 2A and 2B, the PCD particles 16 may have an average particle diameter D of, for example, between about 0.25 millimeter and about 7.0 millimeters, and an average thickness T of, for example, between about 0.1 millimeter and about 5.0 millimeters.

    [0034] As shown in FIG. 2B, in some embodiments, the PCD particles 16 may be at least partially encapsulated with a coating 17 prior to forming a hardfacing material 10 using the PCD particles 16. The coating 17 may be used to protect the polycrystalline diamond material within the PCD particles 16 against thermal degradation (e.g., graphitization) that might occur during formation of a hardfacing material 10 using the PCD particles 16. By way of example and not limitation, the coating 17 may comprise a powder material comprising particles of a metal or metal alloy material that does not serve as a catalyst material for catalyzing the formation of diamond-to-diamond bonds at elevated temperatures and pressures, as described in further detail below. Such catalyst materials may, conversely, contribute to the thermal degradation of diamond material when the diamond material and the catalyst are heated to relatively lower temperatures and pressures. For example, the coating 17 may comprise particles of tungsten metal or a tungsten metal alloy. The coating 17 also may comprise particles of at least one of a carbide material (e.g., tungsten carbide, titanium carbide, tantalum carbide, silicon carbide, etc.), a boride material (e.g., titanium boride), a nitride material (e.g., silicon nitride), and non-polycrystalline diamond grit. Such a powder coating 17 optionally may be subjected to a sintering process to at least partially sinter particles within the powder coating 17. By way of non-limiting example, the PCD particles 16 may be coated using methods such as those disclosed in U.S. Patent No. 7,350,599, which issued April 1, 2008 to Lockwood et al.

    [0035] In additional embodiments, the coating 17 may comprise a layer of one or more of the above-mentioned coating materials deposited by, for example, using a physical vapor deposition (PVD) process or a chemical vapor deposition (CVD) process.

    [0036] As previously mentioned, the PCD particles 16 may comprise a plurality of inter-bonded diamond grains. FIG. 2C is a simplified drawing illustrating how the microstructure of the PCD particles 16 may appear at a magnification of between about 500 times and about 1,500 times.

    [0037] FIG. 2C illustrates a plurality of inter-bonded diamond grains 18, 18'. The diamond grains 18, 18' may have an average particle size within a range extending from about five microns (5.0 µm) to about thirty microns (30.0 µm). In some embodiments, the diamond grains 18, 18' may have a multi-modal grain size distribution. In other words, the diamond grains 18, 18' may comprise a mixture of two, three, or even more different sizes of grains. For example, in the embodiment of FIG. 2C, the inter-bonded diamond grains 18, 18' include both larger diamond grains 18 and smaller diamond grains 18'. The larger and smaller diamond grains 18, 18' are bonded together by diamond-to-diamond bonds at grain boundaries between the diamond grains 18, 18' (the grain boundaries being represented in FIG. 2C by dashed lines) to form the polycrystalline diamond material of the PCD particles 16. In some embodiments, interstitial spaces 20 (shaded black in FIG. 2C) between the inter-bonded diamond grains 18, 18' may be filled with a catalyst material used to catalyze formation of the diamond-to-diamond bonds between the diamond grains 18, 18'. In other embodiments, however, catalyst material may be removed from the interstitial spaces 20 between the inter-bonded diamond grains 18, 18' such that the interstitial spaces 20 comprise voids, as discussed in further detail herein below. In such embodiments, the polycrystalline diamond material of the PCD particles 16 may be porous, and a majority of the pores within the PCD particles 16 may form a continuous open pore network within the polycrystalline diamond material.

    [0038] In some embodiments of the present invention, PCD particles 16 used in the hardfacing material 10 (FIG. 1) may be formed by breaking down (e.g., crushing, milling, grinding, etc.) a relatively larger volume of polycrystalline diamond material. By way of example and not limitation, the PCD particles 16 may be formed by breaking down a layer of polycrystalline diamond material of a cutting element, which previously may have been disposed on a substrate. According to the invention as claimed the PCD particles 16 comprise fragments of a layer of polycrystalline diamond material. In some embodiments, such fragments may be at least substantially planar.

    [0039] FIG. 3 illustrates a cutting element 30 like those often used on drill bits and reamers used to form wellbores in subterranean formations. The cutting element 30 shown in FIG. 3 includes a volume of polycrystalline diamond material 32 bonded to a substrate 34. The volume of polycrystalline diamond material 32 is often referred to in the art as a "diamond table." The volume of polycrystalline diamond material 32 may be formed on the substrate 34, or the volume of polycrystalline diamond material 32 may be formed separately from the substrate 34 and subsequently attached to the substrate 34. As known in the art, polycrystalline diamond material may be formed by subjecting diamond grains to elevated temperatures and pressures to form diamond-to-diamond bonds between the diamond grains. For example, polycrystalline diamond material may be formed by subjecting diamond grains to temperatures greater than about 1500°C and pressures greater than about 5.0 GPa in the presence of a catalyst material such as, for example, cobalt for a time of between about ten seconds and several minutes. The catalyst is used to catalyze formation of the diamond-to-diamond bonds between the diamond grains. Other suitable catalysts are also known in the art. If the temperatures and pressures are sufficiently high (e.g., at a temperature greater than about 3,000°C and a pressure greater than about 13.0 GPa), diamond-to-diamond bonds may form even in the absence of a catalyst.

    [0040] Referring to FIG. 4, the volume of polycrystalline diamond material 32 may be removed from the substrate 34 of the cutting element 30. The volume of polycrystalline diamond material 32 may be removed from the substrate 34 using, for example, a wire Electrical Discharge Machining (EDM) process. Other processes, such as grinding processes, etching processes, or fracturing processes, also may be used to separate the volume of polycrystalline diamond material 32 and the substrate 34. After removing the volume of polycrystalline diamond material 32 from the substrate 34, the volume of polycrystalline diamond material 32 may be broken down to form a plurality of PCD particles 16 (FIGS. 2A-2C) therefrom.

    [0041] Thus, some embodiments of methods of the present invention include forming a plurality of PCD particles 16 from a volume of polycrystalline diamond material 32 that was previously part of a cutting element 30. As a result, in accordance with some embodiments of the present invention, cutting elements 30 (which may or may not have been previously used in drilling or reaming a wellbore) that would otherwise be discarded may be salvaged and recycled by using the cutting elements 30 to form PCD particles 16 (FIGS. 2A-2C) for use in a hardfacing material 10 (FIG. 1). In additional embodiments of methods of the present invention, a volume of polycrystalline diamond material 32 may be formed with the intention of subsequently breaking down the volume of polycrystalline diamond material 32 to form PCD particles 16 (FIGS. 2A-2C) for use in a hardfacing material 10 (FIG. 1).

    [0042] After forming the PCD particles 16, the PCD particles 16 may optionally be subjected to a leaching process to remove catalyst material from interstitial spaces 20 between the inter-bonded diamond grains 18. By way of example and not limitation, the PCD particles 16 may be leached using a leaching agent and process such as those described more fully in, for example, U.S. Patent No. 5,127,923 to Bunting et al. (issued July 7, 1992), and U.S. Patent No. 4,224,380 to Bovenkerk et al. (issued September 23, 1980). Specifically, aqua regia (a mixture of concentrated nitric acid (HNO3) and concentrated hydrochloric acid (HCl)) may be used to at least substantially remove catalyst material from the interstitial spaces 20 between the inter-bonded diamond grains 18 in the PCD particles 16. It is also known to use boiling hydrochloric acid (HCl) and boiling hydrofluoric acid (HF) as leaching agents. One particularly suitable leaching agent is hydrochloric acid (HCl) at a temperature of above 110°C, which may be provided in contact with the PCD particles 16 for a period of about two hours to about 60 hours, depending upon the size of the PCD particles 16. After leaching the PCD particles 16, the interstitial spaces 20 between the plurality of inter-bonded diamond grains 18 within the PCD particles 16 may be at least substantially free of catalyst material used to catalyze formation of diamond-to-diamond bonds between the plurality of inter-bonded diamond grains 18.

    [0043] Additional embodiments of the present invention include material compositions and structures that may be used to form a hardfacing material 10 on an earth-boring tool. Such material compositions and structures also include PCD particles (such as the PCD particles 16 as previously described with reference to FIGS. 2A-2C), and may include a matrix material used to form a matrix phase 14 of hardfacing material 10. By way of example and not limitation, the PCD particles 16 may be incorporated into a welding rod, and the welding rod may be used to deposit hardfacing material 10 on a surface of an earth-boring tool.

    [0044] FIG. 5 is a simplified perspective view of an embodiment of a solid welding rod 40 of the present invention. The solid welding rod 40 shown in FIG. 5 may comprise an at least substantially solid cylinder that includes PCD particles 16 embedded within a matrix material that will ultimately form the matrix phase 14 of the hardfacing material 10 (FIG. 1). Thus, the solid welding rod 40 includes an elongated, generally cylindrical body comprising the matrix material, and the PCD particles 16 are carried by the body. As the matrix material of the welding rod 40 will ultimately form the matrix phase 14 of the hardfacing material 10, the matrix material of the welding rod 40 may have a material composition as previously described for the matrix phase 14 of the hardfacing material 10 of FIG. 1. The solid welding rod 40 may further comprise additional hard particles that include at least one of a carbide material (e.g., tungsten carbide, titanium carbide, tantalum carbide, silicon carbide, etc.), a boride material (e.g., titanium boride), a nitride material (e.g., silicon nitride), and non-polycrystalline diamond grit. The solid welding rod 40 of FIG. 5 may be formed using, for example, a forging process, a casting process, or an extrusion process.

    [0045] FIG. 6A is a simplified perspective view of another embodiment of a tubular welding rod 50 of the present invention. The tubular welding rod 50 shown in FIG. 6A may comprise a generally hollow, cylindrical tube 52 that is at least substantially comprised by a metal or metal alloy that will be used to form the matrix phase 14 of the hardfacing material 10 (FIG. 1). Thus, the matrix material of the welding rod 50 may have a material composition as previously described for the matrix phase 14 of the hardfacing material 10 of FIG. 1. FIG. 6B is a longitudinal cross-sectional view of the tubular welding rod 50 of FIG. 6A. As shown in FIG. 6B, the interior space within the hollow, cylindrical tube 52 may be filled with PCD particles 16. The tube 52 may also contain additional hard particles that include at least one of a carbide material (e.g., tungsten carbide, titanium carbide, tantalum carbide, silicon carbide, etc.), a boride material (e.g., titanium boride), a nitride material (e.g., silicon nitride), and non-polycrystalline diamond grit. One or both ends of the tube 52 may be capped, crimped, or otherwise sealed to prevent the PCD particles 16 (and any other hard particles therein) from falling out from the tube 52. Thus, the tubular welding rod 50 also includes an elongated, generally cylindrical tubular body comprising a matrix material (i.e., tube 52), and the PCD particles 16 are carried by the body. The hollow, cylindrical tube 52 of the welding rod 50 of FIGS. 6A and 6B may be formed using, for example, a forging process, a casting process, or an extrusion process.

    [0046] Embodiments of welding rods of the present invention (e.g., the solid welding rod 40 of FIG. 5 and the tubular welding rod 50 of FIGS. 6A and 6B) may be used to apply hardfacing material 10 to a surface of an earth-boring tool using a torch such as, for example, an oxyacetylene torch or an arc-welding torch. The torch is used to heat an end of the welding rod and, optionally, the surface of the earth-boring tool to which the hardfacing material is to be applied. An end of the welding rod is heated until at least the matrix material in the welding rod begins to melt. As the matrix material at the end of the welding rod begins to melt, the melting matrix material, and PCD particles 16 from the welding rod that become entrained within the melting matrix material, are applied to the surface of the earth-boring tool. After application, the molten matrix material is allowed to cool and solidify on the surface of the earth-boring tool, the PCD particles 16 become embedded within the solidified matrix material. The resulting hardfacing material 10 (FIG. 1) includes a continuous matrix phase 14, which is formed by the matrix material of the welding rod, and a discontinuous phase 12 comprising polycrystalline diamond material that is formed by the PCD particles 16 of the welding rod.

    [0047] Additional embodiments of the present invention include powder feedstock mixtures for use in flame spray processes that include PCD particles 16. For example, a powder feedstock mixture for a flame spray process may comprise a mixture of PCD particles 16, as well as particles of a metal or metal alloy matrix material having a composition as previously described in relation to the matrix phase 14 of the hardfacing material 10 (FIG. 1). The mixture may also comprise additional hard particles that include at least one of a carbide material (e.g., tungsten carbide, titanium carbide, tantalum carbide, silicon carbide, etc.), a boride material (e.g., titanium boride), a nitride material (e.g., silicon nitride), and non-polycrystalline diamond grit. In a flame spray process, such a powder feedstock mixture may be entrained within and carried by a pressurized fluid (e.g., a pressurized gas) to a flame spray nozzle. The pressurized fluid and the powder mixture may be sprayed out from the nozzle and through a flame toward the surface of the earth-boring tool to which the hardfacing material 10 is to be applied. The flame causes the particles of matrix material to at least partially melt. As the powder mixture is sprayed onto the tool, the molten matrix material cools and solidifies, and the PCD particles 16 become embedded within the solidified matrix material. The resulting hardfacing material 10 (FIG. 1) includes a continuous matrix phase 14, which is formed by the particles of matrix material in the powder feedstock mixture, and a discontinuous phase 12 comprising polycrystalline diamond material that is formed by the PCD particles 16 in the powder feedstock mixture.

    [0048] Additional embodiments of the present invention include earth-boring tools having a hardfacing material 10 (as previously described herein in relation to FIG. 1 and including a discontinuous phase 12 comprising finite spatial volumes of polycrystalline diamond material dispersed within a matrix phase 14) on at least a portion of a surface of a body of the tools. The tools may also include at least one cutting element. By way of example and not limitation, earth-boring tools such as, for example, fixed-cutter rotary drill bits, roller cone rotary drill bits, diamond impregnated rotary drill bits, reamer tools, mills, and coring bits may include hardfacing material 10 and may embody the present invention.

    [0049] FIG. 7 illustrates an embodiment of a roller cone drill bit 60 of the present invention. The roller cone drill bit 60 includes a bit body 62 having threads 64 at its proximal longitudinal end for connection to a drill string (not shown). The bit body 62 may comprise a plurality (e.g., three) of head sections 66 (which are separated by the dotted lines in FIG. 7) that are welded together concentrically about a longitudinal axis 67 of the drill bit 60. The threads 64 may be machined in the conical shank region of the bit body 62 after welding together the head sections 66. Two of the head sections 66 are visible from the perspective of FIG. 7.

    [0050] Each head section 66 comprises a head section body or proximal section 68 nearest the threads 64 and a bit leg 70 depending distally therefrom. Each upper section 68 of the drill bit 60 may include a lubricant fluid pressure compensator 72, as known in the art. At least one nozzle 74 may be provided in the bit body 62 for controlling the direction and velocity of pressurized drilling fluid flowing through the bit body 62 and out from the nozzle 74 during drilling operations. A roller cone cutter 76 is rotatably secured to a bearing shaft (not shown) of each respective bit leg 70 of bit body 62. By way of example, the drill bit 60 has three roller cone cutters 76, one of which is obscured from view from the perspective of FIG. 7. Each roller cone cutter 76 has rows of cutting elements 78. The cutting elements 78 may comprise cutting teeth, which may be machined in exterior surfaces of the bodies of the roller cone cutters 76. Alternatively, the cutting elements 78 may comprise separately formed inserts, which may be formed from a wear resistant material such as cemented tungsten carbide and pressed into recesses drilled or otherwise formed in exterior surfaces of the bodies of the roller cone cutters 76.

    [0051] The roller cone drill bit 60 of FIG. 7 may include hardfacing material 10 on one or more surfaces of the drill bit 60. By way of example and not limitation, the outer surfaces of the head sections 66, including exterior surfaces of both the proximal sections 68 of the head sections 66 and the bit legs 70 of the head sections 66 may comprise hardfacing material 10 thereon. Furthermore, hardfacing material 10 may be provided on various surfaces of the roller cone cutters 76. For example, hardfacing material 10 may be provided on gage surfaces 80 of the roller cone cutters 76, on the cutting elements 78 (e.g., on cutting teeth), or on both the gage surfaces 80 and on the cutting elements 78. Hardfacing material 10 also may be applied to surfaces of the drill bit 60 within the fluid passageways (not shown) extending through the drill bit 60, as well as to surfaces of the drill bit 60 proximate the nozzles 74, and other surfaces that might be susceptible to fluid erosion during drilling operations.

    [0052] FIG. 8 illustrates an embodiment of a fixed-cutter drill bit 90 of the present invention. The fixed-cutter drill bit 90 includes a bit body 92 having threads 94 at its proximal longitudinal end for connection to a drill string (not shown). The bit body 92 may comprise a crown 96, which may be formed from a particle-matrix composite material (e.g., a cemented tungsten carbide material) or a metal alloy (e.g., steel). The crown 96 may be attached to a shank 97, and the threads 94 may be machined in the shank 97.

    [0053] The crown 96 of the drill bit 90 may comprise a plurality of blades 98 that are separated from one another by fluid passageways 100. The blades 98 may extend over the face of the crown 96 from a central cone region of the crown 96 to a gage region of the crown 96. Radially outer surfaces of the blades 98 in the gage region of the crown 96 comprise gage surfaces 102 of the drill bit 90. These gage surfaces 102 define the diameter of any wellbore drilled by the drill bit 90. The portions of the fluid passageways 100 between the blades 98 in the gage region of the crown 96 are often referred to in the art as "junk slots."

    [0054] A plurality of cutting elements 104 may be fixedly attached to each of the blades 98. The cutting elements 104 may comprise, for example, PDC cutting elements. Fluid passageways (not shown) also extend through the drill bit 90 to nozzles 106 to allow drilling fluid to be pumped through the drill string (not shown) and the drill bit 90 and out the nozzles 106 during drilling operations.

    [0055] The fixed-cutter drill bit 90 of FIG. 8 may include hardfacing material 10 on one or more surfaces of the drill bit 90. By way of example and not limitation, the gage surfaces 102 may comprise hardfacing material 10 thereon. Furthermore, hardfacing material 10 may be provided on various formation-engaging surfaces of the blades 98. Hardfacing material 10 also may be applied to surfaces of the drill bit 90 within the fluid passageways (not shown) extending through the drill bit 90, as well as to surfaces of the drill bit 90 proximate the nozzles 106, and other surfaces that might be susceptible to fluid erosion during drilling operations.

    [0056] Thus, surfaces of earth-boring tools such as, for example, the roller cone drill bit 60 of FIG. 7 and the fixed-cutter drill bit 90 of FIG. 8, may be hardfaced by bonding particles of polycrystalline diamond material, such as the PCD particles 16 of FIGS. 2A-2C, to the surfaces using a matrix material, which may comprise a metal or metal alloy, as previously described herein.

    [0057] PCD particles 16, as previously described herein, may also be used in other components of earth-boring tools other than hardfacing material to provide wear resistance to the earth-boring tools. As a non-limiting example, PCD particles 16 may be disposed within bit bodies of so-called "diamond-impregnated" rotary drill bits such as those disclosed in, for example, U.S. Patent No. 6,843,333, which issued January 18, 2005 to Richert et al.

    [0058] Embodiment 4: The hardfacing material of any one of Embodiments 1 through 3, wherein interstitial spaces between the plurality of inter-bonded diamond grains within the particles of polycrystalline diamond material are at least substantially free of catalyst material used to catalyze formation of diamond-to-diamond bonds between the plurality of inter-bonded diamond grains.

    [0059] Embodiment 5: The hardfacing material of any one of Embodiments 1 through 4, wherein the particles of polycrystalline diamond material are encapsulated within a coating comprising a metal.

    [0060] Embodiment 6: The hardfacing material of Embodiment 5, wherein the coating further comprises at least one of a carbide material, a boride material, a nitride material, and non-polycrystalline diamond grit.

    [0061] Embodiment 7: The hardfacing material of any one of Embodiments 1 through 6, wherein interstitial spaces between the plurality of inter-bonded diamond grains within the particles of polycrystalline diamond material are at least substantially free of catalyst material used to catalyze formation of diamond-to-diamond bonds between the plurality of inter-bonded diamond grains, and wherein the particles of polycrystalline diamond material are encapsulated within a coating comprising a metal.

    [0062] Embodiment 8: The hardfacing material of any one of Embodiments 1 through 7, wherein the particles of polycrystalline diamond material are at least substantially planar, have an average particle diameter between about 0.25 millimeter and about 7.0 millimeters, and have an average particle thickness between about 0.1 millimeter and about 5.0 millimeters.

    [0063] Embodiment 9: A welding rod comprising a hardfacing material as recited in any one of claims 1 through 8.

    [0064] Embodiment 10: An earth-boring tool comprising a hardfacing material as recited in any one of claims 1 through 8.

    [0065] Embodiment 11: A welding rod for use in applying hardfacing to a surface of a tool, comprising: an elongated, generally cylindrical body comprising a metal matrix material; and particles of polycrystalline diamond material carried by the elongated, generally cylindrical body, the particles of polycrystalline diamond material comprising a plurality of inter-bonded diamond grains.

    [0066] Embodiment 12: The welding rod of Embodiment 11, wherein the elongated, generally cylindrical body comprises a hollow tube, and wherein the particles of polycrystalline diamond material are disposed within the hollow tube.

    [0067] Embodiment 13: An earth-boring tool, comprising: a body; at least one cutting element on the body; and hardfacing material on at least a portion of a surface of the body, the hardfacing material comprising: a metal matrix material; and particles of polycrystalline diamond material embedded within the metal matrix material, the particles of polycrystalline diamond material comprising a plurality of inter-bonded diamond grains.

    [0068] Embodiment 14: The earth-boring tool of Embodiment 13, wherein the body comprises a bit body of a fixed-cutter rotary drill bit, and wherein the at least one cutting element comprises a polycrystalline diamond compact (PDC) cutting element fixedly attached to the bit body.

    [0069] Embodiment 15: The earth-boring tool of Embodiment 13, wherein the body comprises a bit leg of a roller cone rotary drill bit, and wherein the at least one cutting element comprises a roller cone cutter.

    [0070] Embodiment 16: The earth-boring tool of Embodiment 13, wherein the body comprises a roller cone cutter of a roller cone rotary drill bit, and wherein the at least one cutting element comprises a cutting insert or a cutting tooth on the roller cone cutter.

    [0071] Embodiment 17: The earth-boring tool of any one of claims 13 through 16, wherein interstitial spaces between the plurality of inter-bonded diamond grains within the particles of polycrystalline diamond material are at least substantially free of catalyst material used to catalyze formation of diamond-to-diamond bonds between the plurality of inter-bonded diamond grains, and wherein the particles of polycrystalline diamond material are encapsulated within a coating comprising a metal.

    [0072] Embodiment 18: A method of forming a hardfacing material, comprising: subjecting diamond grains to a temperature greater than about 1500°C and a pressure greater than about 5.0 GPa to form diamond-to-diamond bonds between the diamond grains and form a polycrystalline diamond material; and breaking down the polycrystalline diamond material to form particles of polycrystalline diamond material, the particles of polycrystalline diamond material comprising a plurality of inter-bonded diamond grains.

    [0073] Embodiment 19: The method of Embodiment 18, wherein breaking down the polycrystalline diamond material comprises crushing the polycrystalline diamond material.

    [0074] Embodiment 20: The method of Embodiment 18 or Embodiment 19, further comprising catalyzing formation of the diamond-to-diamond bonds between the diamond grains using a catalyst material.

    [0075] Embodiment 21: The method of Embodiment 20, further comprising removing the catalyst material from interstitial spaces between the inter-bonded diamond grains within the particles of polycrystalline diamond material.

    [0076] Embodiment 22: The method of any one of Embodiments 18 through 21, further comprising encapsulating the particles of polycrystalline diamond material with an encapsulant material comprising a metal.

    [0077] Embodiment 23: A method of hardfacing an earth-boring tool, comprising: bonding particles of polycrystalline diamond material including a plurality of inter-bonded diamond grains to a surface of an earth-boring tool using a metal matrix material.

    [0078] Embodiment 24: The method of Embodiment 23, wherein bonding particles of polycrystalline diamond material to a surface of an earth-boring tool comprises: using a welding torch to at least partially melt the metal matrix material; applying the at least partially molten metal matrix material and the particles of polycrystalline diamond material to the surface of the earth-boring tool; and allowing the at least partially molten metal matrix material to cool and solidify on the surface of the earth-boring tool.

    [0079] The foregoing description is directed to particular embodiments for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiments set forth above are possible without departing from the scope of the embodiments disclosed herein as hereinafter claimed, including legal equivalents. It is intended that the following claims be interpreted to embrace all such modifications and changes.


    Claims

    1. An earth-boring tool (60), comprising:

    a body (62);

    at least one cutting element (78) on the body (62); and

    hardfacing material (10) on at least a portion of a surface of the body (62), the hardfacing material (10) comprising:

    a metal matrix material (14); and

    particles of poly crystalline diamond material (16) embedded within the metal matrix material (14), the particles of polycrystalline diamond material (16) comprising a plurality of inter-bonded diamond grains (18, 18'), characterised by the particles of polycrystalline diamond material (16) comprising fragments of a layer of polycrystalline diamond material.


     
    2. The earth-boring tool (60) of claim 1, wherein the body (62) comprises a bit body of a fixed-cutter rotary drill bit, and wherein the at least one cutting element (78) comprises a polycrystalline diamond compact (PDC) cutting element fixedly attached to the bit body.
     
    3. The earth-boring tool (60) of claim 1, wherein the body (62) comprises a bit leg of a roller cone rotary drill bit, and wherein the at least one cutting element (78) comprises a roller cone cutter.
     
    4. The earth-boring tool (60) of claim 1, wherein the body (62) comprises a roller cone cutter of a roller cone rotary drill bit, and wherein the at least one cutting element (78) comprises a cutting insert or a cutting tooth on the roller cone cutter.
     
    5. The earth-boring tool (60) of claim 1, wherein the particles of polycrystalline diamond material (16) comprise at least substantially planar fragments of the layer of polycrystalline diamond material.
     
    6. The earth-boring tool (60) of claim 1, wherein the particles of polycrystalline diamond material (16) are encapsulated within a coating comprising a metal, the metal comprising at least one of a carbide material, a boride material, a nitride material, and non-polycrystalline diamond grit.
     
    7. The earth-boring tool (60) of claim 1 or claim 6, wherein interstitial spaces between the plurality of inter-bonded diamond grains (18, 18') within the particles of polycrystalline diamond material (16) are at least substantially free of catalyst material used to catalyze formation of diamond-to-diamond bonds between the plurality of inter-bonded diamond grains (18, 18').
     
    8. The earth-boring tool (60) of claim 1, wherein the particles of polycrystalline diamond material (16) are at least substantially planar, have an average particle diameter between about 0.25 millimeter and about 7.0 millimeters, and have an average particle thickness between about 0.1 millimeter and about 5.0 millimeters.
     
    9. A method of hardfacing an earth-boring tool (60), comprising:

    providing particles of polycrystalline diamond material (16) including a plurality of inter-bonded diamond grains (18, 18'); and

    bonding the particles of polycrystalline diamond material (16) including a plurality of inter-bonded diamond grains (18, 18') to a surface of an earth-boring tool (60) using a metal matrix material (14);

    characterised by the particles of polycrystalline diamond material (16) comprising fragments of a layer of polycrystalline diamond material.


     
    10. The method of claim 9, wherein bonding particles of polycrystalline diamond material (16) to a surface of an earth-boring tool (60) comprises:

    using a welding torch to at least partially melt the metal matrix material (14);

    applying the at least partially molten metal matrix material and the particles of polycrystalline diamond material (16) to the surface of the earth-boring tool (60); and

    allowing the at least partially molten metal matrix material to cool and solidify on the surface of the earth-boring tool (60).


     
    11. The method of claim 9, wherein providing particles of polycrystalline diamond material (16) including a plurality of inter-bonded diamond grains (18, 18') comprises:

    subjecting diamond grains to a temperature greater than about 1500°C and a pressure greater than about 5.0 GPa to form diamond-to-diamond bonds between the diamond grains and form a polycrystalline diamond material; and

    breaking down the polycrystalline diamond material to form particles of polycrystalline diamond material (16), the particles of polycrystalline diamond material (16) comprising a plurality of inter-bonded diamond grains (18, 18').


     
    12. The method of claim 11, wherein breaking down the polycrystalline diamond material comprises crushing the polycrystalline diamond material.
     
    13. The method of claim 11, further comprising catalyzing formation of the diamond-to-diamond bonds between the diamond grains using a catalyst material.
     
    14. The method of claim 13, further comprising removing the catalyst material from interstitial spaces between the inter-bonded diamond grains (18, 18') within the particles of polycrystalline diamond material (16).
     
    15. The method of claim 11, further comprising encapsulating the particles of polycrystalline diamond material (16) with an encapsulant material comprising a metal.
     


    Ansprüche

    1. Erdbohrwerkzeug (60), umfassend:

    einen Körper (62);

    mindestens ein Schneidelement (78) am Körper (62); und

    Panzerungsmaterial (10) auf mindestens einem Teil der Oberfläche des Körpers (62), wobei die Panzerung (10) umfasst:

    ein Metallmatrixmaterial (14); und

    Teilchen aus polykristallinem Diamantmaterial (16), die in das Metallmatrixmaterial (14) eingebettet sind, wobei die Teilchen aus polykristallinem Diamantmaterial (16) eine Vielzahl von miteinander verbundenen Diamantkörnern (18, 18') umfassen, dadurch gekennzeichnet das die Teilchen aus polykristallinem Diamantmaterial (16) Fragmente einer Schicht aus polykristallinem Diamantmaterial umfassen.


     
    2. Erdbohrwerkzeug (60) nach Anspruch 1, wobei der Körper (62) einen Meißelkörper einer Festmesser-Drehbohrkrone aufweist, und wobei das mindestens eine Schneidelement (78) ein an dem Meißelkörper fest befestigtes Polykristalline-Diamanten-Presskörper(PDC)-Schneideelement umfasst.
     
    3. Erdbohrwerkzeug (60) nach Anspruch 1, wobei der Körper (62) einen Meißelschenkel einer Rollenkegel-Drehbohrkrone aufweist, und wobei das mindestens eine Schneidelement (78) einen Rollenkegelfräser aufweist.
     
    4. Erdbohrwerkzeug (60) nach Anspruch 1, wobei der Körper (62) einen Rollenkegelfräser einer Rollenkegel-Drehbohrkrone aufweist, und wobei das mindestens eine Schneidelement (78) einen Schneideinsatz oder einen Fräszahn auf dem Rollenkegelfräser umfasst.
     
    5. Erdbohrwerkzeug (60) nach Anspruch 1, wobei die Teilchen aus polykristallinem Diamantmaterial (16) zumindest im wesentlichen ebene Fragmente der Schicht aus polykristallinem Diamantmaterial umfassen.
     
    6. Erdbohrwerkzeug (60) nach Anspruch 1, wobei die Teilchen aus polykristallinem Diamantmaterial (16) in einer Beschichtung, die ein Metall umfasst, eingekapselt sind, wobei das Metall mindestens eine aus einem Carbidmaterial, einem Boridmaterial, einem Nitridmaterial und einem nicht-polykristallinen Diamantkorn umfasst.
     
    7. Erdbohrwerkzeug (60) nach Anspruch 1 oder 6, wobei Zwischenräume zwischen der Vielzahl von miteinander verbundenen Diamantkörnern (18, 18') innerhalb der Teilchen aus polykristallinem Diamantmaterial (16) zumindest im Wesentlichen frei von Katalysatormaterial sind, das verwendet wird, um die Bildung von Diamant-zu-Diamant-Bindungen zwischen den mehreren miteinander verbundenen Diamantkörnern (18, 18') zu katalysieren.
     
    8. Erdbohrwerkzeug (60) nach Anspruch 1, wobei die Teilchen aus polykristallinem Diamantmaterial (16) zumindest im Wesentlichen eben sind, einen mittleren Teilchendurchmesser zwischen etwa 0,25 Millimeter und etwa 7,0 Millimeter und eine mittlere Teilchendicke zwischen etwa 0,1 Millimeter und etwa 5,0 Millimeter haben.
     
    9. Verfahren zum Panzern eines Erdbohrwerkzeuges (60), umfassend:

    Bereitstellen von Teilchen aus polykristallinem Diamantmaterial (16) umfassend eine Vielzahl von miteinander verbundenen Diamantkörnern (18, 18'); und

    Binden der Teilchen aus polykristallinem Diamantmaterial (16) umfassend eine Vielzahl von miteinander verbundenen Diamantkörnern (18, 18') auf einer Oberfläche eines Erdbohrwerkzeuges (60) unter Verwendung eines Metallmatrixmaterials (14);

    dadurch gekennzeichnet dass die Teilchen aus polykristallinem Diamantmaterial (16) Fragmente einer Schicht aus polykristallinem Diamantmaterial enthalten.


     
    10. Verfahren nach Anspruch 9, wobei das Binden von Teilchen aus polykristallinem Diamantmaterial (16) an eine Oberfläche eines Erdbohrwerkzeuges (60) umfasst:

    Verwenden eines Schweißbrenners, um das Metallmatrixmaterial (14) zumindest teilweise zu schmelzen;

    Aufbringen des zumindest teilweise geschmolzenen Metallmatrixmaterials und der Teilchen aus polykristallinem Diamantmaterial (16) auf die Oberfläche des Erdbohrwerkzeuges (60); und

    das zumindest teilweise geschmolzene Metallmatrixmaterial auf der Oberfläche des Erdbohrwerkzeuges (60) abkühlen und verfestigen lassen.


     
    11. Verfahren nach Anspruch 9, wobei die Bereitstellung von Teilchen aus polykristallinem Diamantmaterial (16), das eine Vielzahl von miteinander verbundenen Diamantkörnern (18, 18') umfasst, umfasst:

    Diamantkörnern einer Temperatur von mehr als etwa 1500 °C und einem Druck von mehr als etwa 5,0 GPa aussetzen um Diamant-zu-Diamant-Bindungen zwischen den Diamantkörnern und ein polykristallines Diamantmaterial zu bilden; und

    Zerkleinern des polykristallinen Diamantmaterials, um Teilchen aus polykristallinem Diamantmaterial (16) zu bilden, wobei die Teilchen aus polykristallinem Diamantmaterial (16) eine Vielzahl von miteinander verbundenen Diamantkörnern (18, 18') umfassen.


     
    12. Verfahren nach Anspruch 11, wobei das Zerkleinern des polykristallinen Diamantmaterials ein Zermahlen das polykristallinen Diamantmaterials umfasst.
     
    13. Verfahren nach Anspruch 11, weiter umfassend ein Katalysieren der Bildung der Diamant-zu-Diamant-Bindungen zwischen den Diamantkörnern unter Verwendung eines Katalysatormaterials.
     
    14. Verfahren nach Anspruch 13, weiter umfassend Entfernen des Katalysatormaterials aus Zwischenräumen zwischen den miteinander verbundenen Diamantkörnern (18, 18') innerhalb der Teilchen aus polykristallinem Diamantmaterial (16).
     
    15. Verfahren nach Anspruch 11, weiter umfassend Einkapseln der Teilchen aus polykristallinem Diamantmaterial (16) mit einem Einkapselungsmaterial, das ein Metall umfasst.
     


    Revendications

    1. Outil de forage de formation terrestre (60), comprenant :

    un corps (62) ;

    au moins un élément de coupe (78) sur le corps (62) ; et

    une matière de surfaçage (10) sur au moins une portion d'une surface du corps (62), la matière de surfaçage (10) comprenant :

    une matière matricielle métallique (14) ; et

    des particules de matière de diamant polycristallin (16) incorporées à l'intérieur de la matière matricielle métallique (14), les particules de matière de diamant polycristallin (16) comprenant une pluralité de grains de diamant liés entre eux (18, 18'), caractérisé par les particules de matière de diamant polycristallin (16) comprenant des fragments d'une couche de matière de diamant polycristallin.


     
    2. Outil de forage de formation terrestre (60) selon la revendication 1, dans lequel le corps (62) comprend un corps de trépan d'un trépan rotary à dispositif de coupe fixe, et dans lequel l'au moins un élément de coupe (78) comprend un élément de coupe en compact de diamant polycristallin (PDC) attaché de manière fixe au corps de trépan.
     
    3. Outil de forage de formation terrestre (60) selon la revendication 1, dans lequel le corps (62) comprend un montant de trépan d'un trépan rotary à cône à rouleaux, et dans lequel l'au moins un élément de coupe (78) comprend un dispositif de coupe à cône à rouleaux.
     
    4. Outil de forage de formation terrestre (60) selon la revendication 1, dans lequel le corps (62) comprend un dispositif de coupe à cône à rouleaux d'un trépan rotary à cône à rouleaux, et dans lequel l'au moins un élément de coupe (78) comprend un insert de coupe ou une dent de coupe sur le dispositif de coupe à cône à rouleaux.
     
    5. Outil de forage de formation terrestre (60) selon la revendication 1, dans lequel les particules de matière de diamant polycristallin (16) comprennent au moins des fragments sensiblement plats de la couche de matière de diamant polycristallin.
     
    6. Outil de forage de formation terrestre (60) selon la revendication 1, dans lequel les particules de matière de diamant polycristallin (16) sont encapsulées à l'intérieur d'un revêtement comprenant un métal, le métal comprenant au moins un d'une matière de carbure, d'une matière de borure, d'une matière de nitrure et d'un sable de diamant non polycristallin.
     
    7. Outil de forage de formation terrestre (60) selon la revendication 1 ou la revendication 6, dans lequel des espaces interstitiels entre la pluralité de grains de diamant liés entre eux (18, 18') à l'intérieur des particules de matière de diamant polycristallin (16) sont au moins sensiblement exempts de matière de catalyseur utilisée pour catalyser la formation de liaisons diamant-diamant entre la pluralité de grains de diamant liés entre eux (18, 18').
     
    8. Outil de forage de formation terrestre (60) selon la revendication 1, dans lequel les particules de matière de diamant polycristallin (16) sont au moins sensiblement planes, ont un diamètre de particule moyen entre environ 0,25 millimètre et environ 7,0 millimètres et ont une épaisseur de particule moyenne entre environ 0,1 millimètre et environ 5,0 millimètres.
     
    9. Procédé de surfaçage d'un outil de forage de formation terrestre (60), comprenant :

    la fourniture de particules de matière de diamant polycristallin (16) incluant une pluralité de grains de diamant liés entre eux (18, 18') ; et

    la liaison des particules de matière de diamant polycristallin (16) incluant une pluralité de grains de diamant liés entre eux (18, 18') à une surface d'un outil de forage de formation terrestre (60) en utilisant une matière matricielle métallique (14) ;

    caractérisé par les particules de matière de diamant polycristallin (16) comprenant des fragments d'une couche de matière de diamant polycristallin.


     
    10. Procédé selon la revendication 9, dans lequel la liaison des particules de matière de diamant polycristallin (16) à une surface d'un outil de forage de formation terrestre (60) comprend :

    l'utilisation d'une torche de soudage pour faire fondre au moins partiellement la matière matricielle métallique (14) ;

    l'application de la matière matricielle métallique au moins partiellement fondue et des particules de matière de diamant polycristallin (16) à la surface de l'outil de forage de formation terrestre (60) ; et

    la permission donnée à la matière matricielle métallique au moins partiellement fondue de refroidir et se solidifier sur la surface de l'outil de forage de formation terrestre (60).


     
    11. Procédé selon la revendication 9, dans lequel la fourniture de particules de matière de diamant polycristallin (16) incluant une pluralité de grains de diamant liés entre eux (18, 18') comprend :

    la soumission des grains de diamant à une température supérieure à environ 1 500 °C et à une pression supérieure à environ 5,0 GPa pour former des liaisons diamant-diamant entre les grains de diamant et former une matière de diamant polycristallin ; et

    la désagrégation de la matière de diamant polycristallin pour former des particules de matière de diamant polycristallin (16), les particules de matière de diamant polycristallin (16) comprenant une pluralité de grains de diamant liés entre eux (18, 18').


     
    12. Procédé selon la revendication 11, dans lequel la désagrégation de la matière de diamant polycristallin comprend le broyage de la matière de diamant polycristallin.
     
    13. Procédé selon la revendication 11, comprenant en outre la catalyse de la formation des liaisons diamant-diamant entre les grains de diamant en utilisant une matière de catalyseur.
     
    14. Procédé selon la revendication 13, comprenant en outre l'enlèvement de la matière de catalyseur depuis les espaces interstitiels entre les grains de diamant liés entre eux (18, 18') à l'intérieur des particules de matière de diamant polycristallin (16).
     
    15. Procédé selon la revendication 11, comprenant en outre l'encapsulation des particules de matière de diamant polycristallin (16) avec une matière d'encapsulation comprenant un métal.
     




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    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description