JP2012528780A - Polycrystalline diamond - Google Patents

Abstract

  A polycrystalline diamond (PCD) material 10 comprising at least 88% by volume and at most 99% by volume diamond grains 12 and having an average diamond grain proximity of greater than 60.5%. The PCD material 10 is particularly used for ground boring, but is not limited thereto.

Description

  The present invention relates to a polycrystalline diamond (PCD) material, a method of making the same, and a tool including the same, and more particularly, but not exclusively, for use in boring the ground. .

  Polycrystalline diamond (PCD) material includes a mass of inter-grown diamond grains and gaps between the diamond grains. PCDs may be made by exposing diamond particle agglomerates to high pressures and temperatures in the presence of a sintering aid such as cobalt that can promote intergrowth of diamond particles. The sintering aid may be referred to as a diamond catalyst material. Gaps in the sintered PCD material may be completely or partially filled with residual catalyst material. The PCD may be formed on a cobalt bonded tungsten carbide substrate that can provide a source of cobalt catalyst material for PCD.

  PCD materials may be used in a wide variety of tools for cutting, machining, drilling, or disassembling hard or abrasive materials such as rocks, metals, ceramics, composites, and wood-containing materials. Good. For example, tool inserts containing PCD material are widely used in drill bits used to drill the ground in the oil and gas drilling industry. In many of these applications, the temperature of the PCD material can increase as the PCD material engages a rock or other workpiece or high energy object. Unfortunately, the mechanical properties of PCD materials such as wear resistance, hardness, and strength tend to deteriorate at high temperatures, which can be facilitated by the catalyst material remaining inside.

  Akaishi et al., The Material Science and Engineering A (1988), vol. 05/106, no. 1 and 2, pages 517 to 523 disclose fully sintered diamonds having a fine grained uniform microstructure, which diamonds have 1 to 5% by volume of Co or Ni additives. It was synthesized at 7.7 GPa and 2,000 ° C. when powder was used as the starting material.

  European Patent Publication EP1931594 is a method for producing a polycrystalline diamond (PCD) body having a grain size of less than 1 micron immediately after arithmetic mean sintering, wherein the catalytic metal comprises an iron group metal such as cobalt and Disclosed is a method wherein the sintering pressure is between about 2.0 GPa and 7.0 GPa.

  US Patent Application Publication No. 2005/0133277 discloses a PCD made using 65 kilobars and a sintering pressure and temperature of 1,400 ° C.

  There is a need for polycrystalline diamond materials having high wear resistance.

  One aspect of the present invention is greater than about 60%, greater than 60.5%, at least about 61.5 percent, or even at least about 65% mean diamond grain consistency. A polycrystalline diamond (PCD) material is provided that includes diamond grains having: In some embodiments of the invention, the diamond grains have an average diamond grain proximity of up to about 80% or up to about 77%. In one embodiment of the present invention, the average diamond grain proximity may be in the range of 60.5% to about 77%, and in one embodiment the average diamond grain proximity is from 61.5% to about 77%. It may be in the range.

  In some embodiments of the invention, the standard deviation of diamond grain proximity may be up to about 4% proximity, up to about 3% proximity, or up to about 2% proximity. .

In some embodiments of the present invention, the volume of the PCD material may be at least about 0.5 mm ² , at least about 75 mm ² , at least about 150 mm ² , or at least about 300 mm ² .

  In one embodiment of the invention, the diamond grains may have a size distribution characteristic where at least about 50% of the particles have an average size greater than about 5 microns. In some embodiments, at least about 15% or at least about 20% of the particles have an average size ranging from about 10 microns to about 15 microns.

  In one embodiment of the present invention, the PCD material may include diamond grains having a multimodal size distribution.

  In some embodiments of the invention, the diamond grains are greater than 0.5 microns or greater than 1 micron and up to about 60 microns, up to about 30 microns, up to about 20 microns, up to about 15 microns, Or it may have an average size of up to about 7 microns. In some embodiments of the present invention, the PCD material may include diamond grains having an average size of up to about 15 microns, less than about 10 microns, or up to about 8 microns. In some embodiments of the invention, the diamond grains have an average in the range of about 0.5 microns to about 20 microns, in the range of about 0.5 microns to about 10 microns, or in the range of about 1 micron to about 7 microns. You may have a size.

  In some embodiments of the invention, the content of diamond in the PCD material may be at least about 88%, at least about 90%, or at least about 91% by volume of the PCD material. In one embodiment, the diamond content may be up to about 99% by volume of the PCD material. In some embodiments of the invention, the diamond content of the PCD material may range from about 88% to about 99% by volume of the PCD material, or from about 90% to about 96% by volume.

  In one embodiment, the PCD material may include a diamond catalyst material, and in one embodiment, the diamond catalyst material content may be up to about 9% by volume of the PCD material. In one embodiment, the diamond catalyst material content may be at least about 1% by volume of the PCD material. In some embodiments of the invention, the PCD material is in the range of about 1% to about 10%, about 1% to about 8%, or about 1 to about 4% by volume of the PCD material. May contain a diamond catalyst material.

  In some embodiments of the invention, the PCD may have an average interstitial mean free path of up to about 1.5 microns, up to about 1.3 microns, or up to about 1 micron. Good. In some embodiments of the invention, the PCD has an average interstitial mean free path of at least about 0.05 microns, at least about 0.1 microns, at least about 0.2 microns, or at least about 0.5 microns. You may have. In some embodiments, the PCD is an average in the range of 0.05 microns to about 1.3 microns, in the range of about 0.1 microns to about 1 micron, or in the range of about 0.5 microns to about 1 micron. May have a mean interstitial free path.

  In some embodiments of the present invention, the standard deviation of mean free path may be in the range of about 0.05 microns to about 1.5 microns, or in the range of about 0.2 microns to about 1 micron.

  In some embodiments of the present invention, the PCD material may have an average interstitial size of at least about 0.5 microns, at least about 1 micron, or at least about 1.5 microns. In some embodiments of the present invention, the PCD material may have an average interstitial size of up to about 3 microns or up to about 4 microns. In some embodiments, the standard deviation of the size distribution may be up to about 3 microns, up to about 2 microns, or even up to about 1 micron.

  In one embodiment of the invention, the PCD material may comprise a filter material comprising a ternary carbide of formula MxM'yCz, where M is at least one selected from the group consisting of transition metals and rare earth metals. M ′ is an element selected from the group consisting of Al, Ga, In, Ge, Sn, Pb, Ti, Mg, Zn, and Cd, and x is 2.5 to 5.0. Range, y is in the range of 0.5 to 3.0, z is in the range of 0.1 to 1.2, and the PCD is an average size in the range of 0.5 to 10 microns. Diamond grains having In some embodiments, M may be selected from the group consisting of Co, Fe, Ni, Mn, Cr, Pd, Pt, V, Nb, Ta, Ti, Zr, Ce, Y, La, and Sc. Good. In one embodiment, x may be 3. In one embodiment, y may be 1.

  In some embodiments, the filler material may comprise at least about 30% by volume or at least about 40% by volume of the ternary carbide material. In one embodiment, the filler material comprises a unique ternary carbide material and one or more other intermetallic compounds such that free or unbound M is not present in the filler material. You may go out. In some embodiments, the filler material is a free or unreacted catalyst material, or other carbide formed with Cr, V, Nb, Ta, and / or Ti, or a free or unreacted catalyst. Both materials and other carbides may further be included. In one embodiment, the filler material may comprise at least about 40% by volume or at least about 50% by volume of intermetallic or ternary carbides based on tin.

  In some embodiments of the present invention, the PCD material may have an oxidation initiation temperature of at least about 800 ° C, at least about 900 ° C, or at least about 950 ° C.

  The PCD material according to the present invention comprises a step of forming a plurality of diamond grains into an agglomerate, and the agglomeration of the diamond grains in a presence of a diamond metal catalyst material at a temperature sufficiently high to melt the catalyst material. And subjecting to pressure treatment at a pressure of greater than 6.0 GPa, at least about 6.2 GPa, or at least about 6.5 GPa, and sintering the diamond grains to form a PCD material. Alternatively, the diamond grains in this agglomerate have a size distribution characteristic in which at least 50% of the particles have an average size, ie, greater than about 5 microns. In some embodiments, at least about 15% or at least about 20% of the particles have an average size ranging from about 10 to about 15 microns. In some embodiments of the present invention, the pressure is up to about 8 GPa, lower than 7.7 GPa, up to about 7.5 GPa, up to about 7.2 GPa, or up to about 7 GPa. 0.0 GPa. This method is one embodiment of the present invention.

  In one embodiment of the present invention, the method includes introducing an additive material into the agglomerate, the additive material comprising V, Ti, Mo, Zr, W, Ta, Hf, Si, Sn, or Al. Containing at least one element selected from: In some embodiments, the additive material comprises a compound or particle containing at least one element selected from V, Ti, Mo, Zr, W, Ta, Hf, Si, Sn, or Al. May be.

  In one embodiment of the present invention, the method may include introducing a metal other than the diamond catalyst material into the pores or gaps in the agglomerates. In one embodiment, the metal may not be a diamond catalyst. In one embodiment, the catalyst material may include Co and the metal may be Sn.

  In one embodiment of the method, the catalyst material may be a metal catalyst material. In some embodiments, the catalyst material may include Co, Fe, Ni, and Mn, or may include an alloy that includes any of these.

  In some embodiments of the method, the PCD material may be sintered over a period of time ranging from about 1 minute to about 30 minutes, ranging from about 2 minutes to about 15 minutes, or ranging from about 2 minutes to about 10 minutes.

  In some embodiments of the method, the temperature is in the range of about 1,400 ° C. to about 2,300 ° C., in the range of about 1,400 ° C. to about 2,000 ° C., 1,450 ° C. to about 1,700 ° C. Or about 1,450 ° C. to about 1,650 ° C.

  In some embodiments of the invention, the method may include subjecting the PCD material to a heat treatment at a temperature of at least about 500 ° C., at least about 600 ° C., or at least about 650 ° C. for at least about 30 minutes. Good. In some embodiments, the temperature may be up to about 850 ° C, up to about 800 ° C, or up to about 750 ° C. In some embodiments, the PCD body may be subjected to a heat treatment of up to about 120 minutes or up to about 60 minutes. In one embodiment, the PCD body may be subjected to heat treatment in vacuum.

  Embodiments of the method of the present invention include subjecting the PCD material to further pressure treatment at least about 2 GPa, at least about 5 GPa, or even at least about 6 GPa. In some embodiments, additional pressure treatment may be applied over a period of at least about 10 seconds or at least about 30 seconds. In one embodiment, additional pressure treatment may be applied over a period of up to about 20 minutes.

  In one embodiment of the present invention, the method may include removing the diamond metal catalyst material from the interstices between the diamond grains of the PCD material.

  Embodiments of the present invention include an embodiment of a volume of PCD material according to aspects of the present invention for cutting at least a portion of a PCD structure, boring a body, or disassembling a body. I will provide a. In some embodiments, at least a portion of the volume of the PCD material may have a thickness in the range of about 3.5 mm to about 12.5 mm, or in the range of about 4 mm to about 7 mm.

  In one embodiment of the present invention, the PCD structure comprises a region adjacent to the surface comprising at most about 2% by volume of diamond catalyst material and a region remote from the surface comprising greater than about 2% by volume of diamond catalyst material. You may have. In some embodiments, the region adjacent to the surface may extend from the surface to a depth of at least about 20 microns, at least about 80 microns, at least about 100 microns, or even at least about 400 microns. In one embodiment, at least a portion of the region adjacent to the surface may be a generally shaped layer or hierarchy.

  Embodiments of the present invention provide a tool or tool component for cutting a body, boring the body, or disassembling the body, including embodiments of PCD structures according to aspects of the present invention. In some embodiments, the tool or tool component is cut, crushed, ground, drilled, grounded, drilled, rock drilled, or other abrasive applications, such as cutting metal and machine It may be for processing. In one embodiment, the tool component may be a drill bit insert, such as a rotary shear cutting bit, for boring the ground used in the oil and gas drilling industry. In one embodiment, the tool may be a rotary drill bit for boring the ground.

  In one embodiment, the insert includes an embodiment of a PCD material according to the present invention, which is bonded to a bonded carbide substrate, and the insert is used in a drill bit for boring the ground.

  In one embodiment of the present invention, the tool component may include an embodiment of a PCD structure bonded to a bonded carbide substrate at an interface. In one embodiment, the PCD structure may be integrally formed with the bonded carbide substrate. In one embodiment, the interface may be substantially planar. In one embodiment, the interface may be substantially non-planar.

  Non-limiting embodiments will now be described with reference to the drawings.

FIG. 3 shows a schematic diagram of a microstructure of an embodiment of a PCD material. FIG. 3 shows a processed image of a micrograph of a polished section of an embodiment of a PCD material. It is a frequency distribution of the diamond grain proximity | contact of embodiment of a PCD material, Comprising: It is a figure which shows the state which piled up the fitting normal curve on this distribution. FIG. 5 shows a number frequency graph of equivalent circle diameter (ECD) particle size shown on the horizontal axis for an embodiment of PCD material. FIG. 2 shows a schematic view of an embodiment of a rotary drill bit insert for boring the ground.

  In all the drawings, the same reference numerals refer to the same features.

  As used herein, a “polycrystalline diamond” (PCD) material is a lump of diamond grains, a substantial portion of which is directly interconnected with each other, and the diamond content is at least about 80 volume of the material. % Is included. In one embodiment of the PCD material, the gaps between the diamond grains may be at least partially filled with a binding material comprising a diamond catalyst. As used herein, “gap” or “interstitial region” is the region between diamond grains of PCD material. In embodiments of the PCD material, the gaps or interstitial regions may be substantially or partially filled with a material other than diamond, or may be substantially empty. Embodiments of the PCD material may include at least one region in which the catalyst material is removed from the gap leaving an interstitial void between the diamond grains.

  In the field of quantitative stereography, “proximity” is understood as a quantitative measure of interphase contact, particularly as applied to bonded carbide materials. “Proximity” is defined as the internal surface area of a phase shared by particles of the same phase in a substantially two-phase microstructure (Underwood, EE, “Quantitative Stereography”). , Addison-Wesley, Reading MA 1970; German, RM, “The Contiguity of Liquid Phase Sintered Microstructures, 1989, Metallurgical Transact. 1247-1252). As used herein, “diamond proximity” is a measure of contact or bonding between diamonds, or a combination of contact and bonding within a PCD material.

  As used herein, “metal” materials are understood to include metals that are in a non-alloyed or alloyed form and that have metallic properties such as high conductivity.

  As used herein, diamond “catalyst material”, which may be referred to as a solvent / catalyst material for diamond, refers to the growth of diamond or direct inter-growth between diamond grains, where the diamond is thermodynamic. Means a material that can be promoted under stable pressure and temperature conditions.

  Filler material is understood to mean a material that fully or partially fills the pores, gaps or interstitial regions within the polycrystalline structure.

  The size of the particles may be expressed in terms of equivalent circle diameter (ECD). As used herein, the “equivalent circle diameter” (ECD) of a particle is the diameter of a circle having the same area as the cross section through the particle. The ECD size distribution and average size of multiple particles is measured using individual cross-sections through the body or image analysis of the surface of the body for each individual unbound particle or for particles bound together in the body. May be.

  As used herein, the terms “average” and “mean” have the same meaning and are interchangeable.

  With reference to FIGS. 1 and 2, an embodiment of the PCD material 10 includes diamond grains 12 having an average diamond grain proximity of greater than 60.5%. The diamond grains 12 form a skeletal mass that defines gaps or interstitial regions 14 between the grains. The length of the perimeter of the diamond is determined by summing the combined lengths of all the points passing through all points present on the bonding interface or contact interface 16 between the diamond grains within the section of the PCD material, and determining the perimeter of the diamond The combined length of the lines passing through all the points present on all the interfaces 18 between the diamond and the interstitial region in the section of material is determined to determine the perimeter of the binder.

As used herein, “diamond grain proximity” κ is calculated by the following equation using data obtained from image analysis of polished sections of PCD material.
κ = 100 × [2 × (δ−β)] / [(2 × (δ−β)) + δ]
(Where δ is the circumference of the diamond and β is the circumference of the binder).

  As used herein, the perimeter of a diamond is the portion of the diamond grain surface that is in contact with other diamond grains. This value is measured for a given volume as the overall inter-diamond contact area divided by the overall diamond grain surface area. The circumference of the binder is a part of the diamond grain surface that is not in contact with other diamond grains. In practice, the proximity measurement is performed by image analysis of the surface of the polished section. The total length of the lines passing through all points present on all inter-diamond interfaces in the analytical section is summed to determine the circumference of the diamond, and the same is true for the circumference of the binder. Do.

  Images used for image analysis should be obtained using scanning electron micrographs (SEM) taken using backscattered electron signals. An optical electron micrograph may not have sufficient depth of focus and may provide a substantially different contrast. A method for measuring diamond grain proximity requires that distinct diamond grains in contact with or bonded to each other can be distinguished from a single diamond grain. Appropriate contrast between diamond grains and the boundary region between these diamond grains can be important in proximity measurements because the boundaries between grains can be identified based on grayscale contrast. . The boundary region between the diamond grains may contain an included material such as a catalyst material that can assist in identifying the boundary between the particles.

  FIG. 2 shows an example of a processed SEM image of a polished section of PCD material 10, where the boundaries 16 between the diamond grains 12 are shown. These boundaries 16 were obtained by image analysis software and were used to measure the circumference of the diamond and subsequently calculate the diamond grain proximity. The non-diamond region 14 is shown as a dark region, and the perimeter of the binder was derived from the cumulative length of the boundary 18 between the diamond 12 and the non-diamond or interstitial region 14.

  Referring to FIG. 3, the average diamond grain proximity measured for the PCD material embodiment, whose processed image is shown in FIG. 2, is about 62%. The measured data is shown fitted to a normal or Gaussian curve, from which the standard deviation of diamond grain proximity can be determined.

  As used herein, “interstitial mean free path” within a polycrystalline material that includes an internal structure that includes interstitial or interstitial regions such as PCD is the difference between the perimeters of interstitial lengths. Is understood to mean the average distance traversed between each of the grids. The average mean free path is determined by averaging the lengths of many lines drawn on a micrograph of a polished sample cross section. The standard deviation of the mean free path is the standard deviation of these values. The diamond mean free path is similarly defined and measured.

  The homogeneity or uniformity of the PCD structure can be quantified by performing a statistical evaluation using a number of micrographs of the polished section. The distribution of the filler phase, which can then be easily distinguished from the distribution of the diamond phase using electron microscopy, is then measured in a manner similar to that disclosed in EP 0974756 (see also WO 2007/110770). Can do. This method allows a statistical evaluation of the average thickness of the binder phase along several arbitrarily drawn lines that pass through the microstructure. This binder thickness measurement is also referred to as “mean free path” by those skilled in the art. In the case of two materials with similar overall composition or binder content and average diamond particle size, materials with smaller average thickness tend to be more homogeneous, although the diamond phase binder has a finer scale. This is because it suggests the distribution of. Furthermore, the smaller the standard deviation of this measurement, the more homogeneous the structure. A large standard deviation suggests that the binder thickness varies widely throughout the microstructure, i.e., the structure is not uniform and includes widely different structure types.

  For illustration purposes, referring to FIG. 4, which shows one non-limiting example of a multimodal particle size distribution, the multimodal size distribution of a lump of particles is that the particle has multiple peaks 20, each peak 20 being It is understood to mean having a size distribution corresponding to each “mode”. A multimodal polycrystalline body typically includes providing a plurality of sources of a plurality of particles, each source comprising particles having a substantially different average size. And by blending together the particle (s) from this source. Measurement of the size distribution of the blended particles can reveal completely different peaks corresponding to completely different modes. When the particles are sintered together to form a polycrystalline body, the size distribution further changes as the particles are compressed and crushed together, resulting in an overall reduction in the size of the particles. Nevertheless, the multimodality of the particles can still be clearly shown from image analysis of the sintered article.

  Unless otherwise indicated herein, dimensions, such as size, distance, perimeter, ECD, and mean free path, as well as particle proximity in the PCD material are determined by the surface of the body containing the PCD material. Or it refers to the dimension measured in a section passing through the body, and no stereographic correction was applied. For example, the size distribution of the diamond grains shown in FIG. 4 was measured using image analysis performed on the polished surface, and Saltykov correction was not applied.

  In measuring the mean and deviation of quantities, such as particle proximity, or other statistical parameters measured using image analysis, we use several images of different parts of the surface or section, Increase the reliability and accuracy of statistics. The number of images used to measure a given quantity or parameter may be at least about 9 or even up to about 36. The number of images used may be about 16. The resolution of the image needs to be high enough so that the interparticle and interphase boundaries are clearly displayed. In statistical analysis, typically 16 images are taken at various regions on the surface of the body containing PCD material, and statistical analysis is performed on each image as well as across all images. Each image should contain at least about 30 diamond grains, but more particles allow for more reliable and accurate statistical image analysis.

  The catalyst material may be introduced into the agglomerates of diamond grains for sintering by any method known in the art. One method includes depositing a metal oxide on the surface of the plurality of diamond grains by precipitation from an aqueous solution prior to forming a consolidation into agglomerates. Such a method is also disclosed in PCT publication numbers WO2006 / 032984 and WO2007 / 110770. Another method includes the steps of preparing or providing a metal alloy comprising a diamond catalyst material, such as a cobalt-tin alloy in powder form, and prior to consolidating them into agglomerates, the powder and a plurality of diamond grains. Blending. The blending step may be performed using a ball mill. Other additives may be blended into the agglomerates.

  In one embodiment, the agglomerates of diamond grains, including any catalyst material particles or additive material particles that may have been introduced, may be formed into an unbonded or loosely bonded structure. May be disposed on the bonded carbide substrate. The bonded carbide substrate may contain a source of diamond catalyst material, such as cobalt. The agglomerate and substrate assembly may be encapsulated in a capsule suitable for an ultra-high pressure furnace apparatus that can be placed under a pressure higher than 6 GPa. Various types of ultra high pressure devices are known and can be used, including belt, toroidal, cubic, and square multi-anvil systems. The capsule temperature should be high enough so that the catalyst material source melts and low enough so that substantial conversion of diamond to graphite is avoided. The time should be long enough to complete the sintering, but as short as possible to maximize productivity and reduce costs.

  PCT Publication No. WO2009 / 027948 describes a polycrystalline diamond material that includes a diamond phase and a filler material, where the filler material contains ternary carbides, and PCT Publication No. WO2009 / 027949 is A polycrystalline diamond material is described that includes intergrown diamond grains and a filler material comprising a tin-based intermetallic or ternary carbide compound formed with a metal catalyst.

The PCD material according to the invention has the advantage of increasing the wear resistance. This material may have the advantage of increasing strength and increasing thermal stability. Any or all of these advantages can be derived from the high diamond proximity of the PCD material. If the average diamond grain proximity is much lower than about 60%, high wear resistance, strength, or thermal stability, or a combination of these properties cannot be shown. In some embodiments of the present invention, high diamond grain proximity can be obtained from the use of diamond grains having a multimodal size distribution in which the particle size distribution characteristics are selected according to embodiments of the present invention. If the standard deviation of diamond grain proximity is much higher than about 4% proximity, the benefits resulting from having high average grain proximity may be significantly reduced. If the diamond grain proximity is significantly higher than about 80% or even higher than about 77%, the fracture resistance of the PCD material may be too low. If the volume of the PCD material is much less than about 0.5 mm ² , it may be too small for practical use in certain cutting or drilling operations.

  Embodiments of the present invention have high strength, wear resistance, and thermal stability. High proximity and interparticle bonding can provide high strength, wear resistance, and thermal stability. Without being bound by theory, the high thermal stability or heat resistance can be attributed to the narrow interfacial area between the catalyst material and the diamond within the microstructure.

  Embodiments of the PCD material according to the present invention show high diamond proximity and high interparticle bonding, more homogeneous spatial distribution of diamond grains, low porosity and less total catalyst content, all of which are generally beneficial. Can be considered. Improved homogeneity can result in less variation in the performance of the PCD in use.

  In some embodiments of the invention, on the one hand high proximity and / or high homogeneity and / or low content of metal catalyst in the PCD and on the other hand at least two peaks or modes, or at least three peaks or modes. In combination with a size distribution that can lead to a substantial improvement in the wear resistance and other properties of PCD, so that in rock drilling or ground boring applications, especially in rock drilling by shear cutting, High service life and cutting or penetration rates of polycrystalline diamond elements can be provided. This combination of features may be synergistic.

  Metal catalyst materials for diamond can provide excellent interparticle diamond bonding and sintering, and as a result, PCD materials with high wear resistance and strength. However, the remaining metal catalyst material may remain in the sintered PCD and may be located in the gaps between the diamond grains, which may reduce the thermal stability of the PCD material. “Thermal stability” refers to the relative strength of important mechanical properties of the PCD material, such as wear resistance and strength, as a function of temperature, in particular as a function of temperature up to about 700 ° C. or even up to about 800 ° C. Sintering of PCD materials using pressures greater than 6.0 GPa can facilitate increasing the thermal stability of PCDs containing metal filler materials. A small amount of catalyst material in the sintered PCD can increase thermal stability. This is because the catalyst material can facilitate the reconversion of diamond to graphite at the high temperatures and ambient pressures typically used during use. Such reconversion can significantly weaken the PCD material. In addition, metal catalyst materials generally have a higher coefficient of thermal expansion than diamond, and their presence can increase internal stress in the PCD as the temperature increases or decreases, which weakens the material. there's a possibility that. Metal catalyst materials may also be susceptible to oxidation, thus further increasing internal stress.

  The embodiment of the tool according to the invention has a high performance. In particular, drill bits for drilling the ground with high diamond grain proximity and inserts containing PCD sintered using pressures above 6 GPa have excellent performance in oil and gas drilling applications Can be shown. Similar benefits can be obtained when other catalyst materials are used.

  If the pressure used to sinter the PCD material is less than about 6 GPa, the diamond grain proximity may not be high enough and some mechanical properties such as wear resistance, thermal stability, and strength May not be substantially high. In an embodiment of the method of the invention, the pressure should be as low as possible but still above 6 GPa in order to be able to use a larger reaction volume and consequently sinter larger articles. More desirable. The use of lower pressure can reduce cost and design policy complexity. In some embodiments of the method of the present invention where the diamond grains have an average size of 1 micron or less, sintering pressures greater than about 7.0 GPa can improve the sintering of the submicron diamond grains.

  Embodiments of the method of the present invention have the advantage that the PCD material can be formed using higher temperatures by sintering, which depends on the nature of the material, especially the filler material used and / or It can be beneficial if the catalyst material has a relatively high melting point.

  Embodiments of the method of the present invention can be particularly beneficial when the polycrystalline diamond material includes a filler material that includes a ternary carbide material, and in particular can increase the thermal stability of the PCD material. This is believed to occur because the ternary metal carbide can be relatively inert to diamond. Embodiments of the method of the present invention may be particularly beneficial for types of PCD materials that include a tin-based intermetallic or ternary carbide compound-containing filler material formed with a diamond metal catalyst. An embodiment of the method of the present invention is a PCD material having a filler material comprising cobalt and tin, wherein the average diamond particle size is less than about 10 microns and at least a portion of the filler material is introduced by infiltration. This can be particularly beneficial when making the material. Embodiments of the method of the present invention have the advantage of substantially reducing the occurrence of defects associated with insufficient sintering that tends to occur near the top surface of the PCD structure. As a result, fewer PCD elements can be rejected, resulting in improved process economics. It is believed that PCD materials tend to have high strength, wear resistance, and thermal stability, including oxidation resistance.

  The thermal stability of embodiments of the PCD material according to the present invention, in particular the oxidation onset temperature measured using thermogravimetric analysis (TGA), can be significantly increased. Such an embodiment can be thermally stable, can exhibit superior performance in applications such as oil and gas drilling, and the temperature of the PCD cutter element reaches a temperature above about 700 ° C. can do. The oxidation onset temperature is measured using thermogravimetric analysis (TGA) in the presence of oxygen, as is known in the art.

  Tools comprising PCD materials according to the present invention may be particularly advantageous for metal cutting or machining due to the high thermal stability and heat resistance of PCD materials.

  Embodiments of the invention are described in more detail with reference to the following examples, which are not intended to limit the invention.

(Example 1)
Agglomerates of diamond grains having an average size of about 8 microns are obtained from diamond powders obtained from two sources each having an average particle size in the range of about 1 micron to about 4 microns and in the range of about 7 microns to about 15 microns. Formed by blending. The blended diamond grains were treated with acid to remove surface impurities that may have been present. Vanadium carbide (VC) powder and cobalt (Co) powder were introduced into the diamond powder by blending the VC and Co particles with the diamond powder using a planetary ball mill. The average size of the VC particles was about 4 microns, and the VC content in the agglomerates was about 3% by weight. The agglomerates are then formed into layers on a substrate comprising Co-bonded tungsten carbide (WC), encapsulated in a capsule and placed in an ultra-high pressure furnace to form a pre-sinter assembly, then known in the art As described above, degassing was performed in vacuum to remove impurities on the surface from the diamond grains. The diameter of the substrate was slightly larger than about 13 mm and the height was about 10 mm.

  PCD material formed by pre-sintering assembly in ultra high pressure furnace under pressure of about 6.8 GPa and temperature of about 1,600 ° C. to sinter diamond grains and integrally with carbide substrate A PCD compact including the following layers was formed. The PCD layer was about 2 mm thick. During the sintering process, molten cobalt obtained from the substrate and containing dissolved W or WC or both in solution penetrated into the agglomerates of diamond grains.

  Sections were cut from the PCD material and the surface of the sections was polished. Sixteen digital images of the microscopic area were obtained at different positions on the section surface using scanning electron micrographs (SEM) using backscattered electron signals. The resolution of the image was 0.04717 μm per pixel. Image analysis is performed on each of the images to determine average diamond grain proximity, average diamond grain ECD, average interstitial ECD, diamond grain mean free path, and interstitial mean free path, and standard deviation of each of these quantities did. These quantities were then averaged throughout the quantities obtained for all images. In the case of diamond grain and interstitial ECD sizing, the size distribution was more fully characterized as described below. When performing image analysis, the contrast between the diamond grains and the boundary region between the diamond grains was adjusted based on the gray scale contrast so that the boundaries between the grains were enhanced.

  Image analysis was performed using software having the trade name analySIS Pro (trademark of Olympus Soft Imaging Solutions GmbH) from Soft Imaging System® GmbH. The software has a “Separate Grains” filter that produces satisfactory results when the structure to be separated according to the operating manual is a sealed structure. It is therefore important to fill every hole before applying this filter. For example, the “Morph.Close” command may be used, or help may be obtained from the “Fillhole” module. In addition to this filter, the “Separator” is another powerful filter that can be used for particle separation. This separator can also be applied to color and gray value images according to the operating manual.

  The results of image analysis are summarized in Tables 1 and 2. The diamond content was measured to be about 90.8% by volume, the diamond grain proximity was about 68.4%, and the average size of the sintered diamond grains was about 6.3 microns with respect to the equivalent circle diameter. It was. The average interstitial mean free path of the PCD material was about 0.52 (± 0.46) microns.

The data relates to a two-dimensional measurement obtained from image analysis of a scanning electron micrograph and is not corrected for three dimensions. For example, the quoted average diamond particle size is the average size corresponding to the cross-sectional area of the diamond particles. Diamond and interstitial sizes are calculated as equivalent circle diameter (ECD) by determining the cross-sectional area and calculating the diameter of a circle having that area. Statistical parameters d10, d50, d75, and d90 refer to the size (ECD) at which 10%, 50%, 75%, and 90% of the particles are less than that value, respectively. The maximum size is a size that is substantially free of larger particles. The parameters “low (95%)” and “top (95%)” refer to size values at which 5% of the particles are less than and above that value, respectively.

(Example 2)
Agglomerates of diamond grains having an average size of about 10 microns can range from about 0.5 microns to about 3 microns, from about 2 microns to about 5 microns, from about 4 microns to about 9 microns, about 7 microns. Formed by blending diamond powders from five sources each having an average particle size in the range of from about 15 microns to about 15 microns and in the range of from about 10 microns to about 30 microns. The blended diamond grains were treated with acid to remove any surface impurities that may be present. Vanadium carbide (VC) powder and cobalt (Co) powder were introduced into the diamond powder by blending the VC and Co particles with the diamond powder using a planetary ball mill. The average size of the VC particles was about 4 microns and the VC content in the agglomerates was about 3% by weight. The agglomerates are then formed into a layer on a substrate comprising Co-bonded tungsten carbide (WC) and encapsulated in a capsule for an ultra high pressure furnace to form a pre-sinter assembly, then known in the art Thus, this was degassed in a vacuum to remove surface impurities from the diamond grains. The diameter of the substrate was slightly larger than about 13 mm and the height was about 2 mm.

  The pre-sintering assembly is placed in an ultra high pressure furnace under a pressure of about 8 GPa and a temperature of about 1,700 ° C. to sinter the diamond grains and form a layer of PCD material integrally formed with the carbide substrate. A PCD compact containing was formed. The PCD layer was about 2 mm thick. During the sintering process, molten cobalt obtained from the substrate and containing dissolved W or WC or both in solution penetrated into the agglomerates of diamond grains.

An SEM image of the PCD material was obtained as described in Example 1, except that the image resolution was 0.09434 μm per pixel. The results of image analysis of the images are shown in Table 3 and Table 4 below. The diamond content was about 90.7% by volume, the diamond grain proximity was about 70.3%, and the average size of the sintered diamond grains was about 7.4 microns with respect to the equivalent circle diameter.

  The PCD compact was processed to form a test PCD cutter insert, which was subjected to a wear test. For wear testing, the insert was used in a vertical turret milling machine to cut a length of workpiece material containing granite until the insert broke or failed due to excessive wear. The distance cut through the workpiece before the insert is deemed to be defective can indicate the expected service life in use. The cut distance achieved with the test insert was about 75% longer than the distance achieved using a control PCD cutter insert sintered at a pressure of about 5.5 GPa and containing no VC additive. It was observed that the abrasion resistance of the test cutter insert was significantly enhanced.

(Example 3)
Test and control PCD material samples were prepared using sintering pressures of 6.8 GPa and 5.5 GPa, respectively. In all other respects, test and control samples were made in the same way. The raw material diamond powder was prepared by blending diamond grains from three sources, each source having a different average particle size distribution. The size distribution of the particles in the resulting blended powder is such that 9.8% by weight of the particles have an average particle size of less than 5 microns and 7.6% by weight of the particles have an average particle size in the range of 5 to 10 microns. And 82.6% by weight of the particles had a size distribution characteristic with an average particle size greater than 10 microns. The blended diamond grains had an average size of about 20 microns.

  Cobalt and tin were deposited on the surface of the diamond grains, using a method that included depositing cobalt oxide and tin oxide on the surface from an aqueous solution. Cobalt-tin was found to occupy about 7.5% of the coated diamond mass and dispersed throughout the particle surface as nanoscale formations.

  Cobalt-tin coated diamond grains are formed into agglomerates on the surface of a cobalt bonded tungsten carbide substrate and the assembly is encapsulated in a refractory metal jacket to form a pre-compression assembly from which air Was substantially removed. The pre-compression assembly was placed in a capsule for a high pressure high temperature furnace.

  The test material was placed under a pressure of about 6.8 GPa and a temperature of 1,550 ° C. for about 9 minutes to form a compact comprising a sintered PCD mass bonded to a tungsten carbide substrate.

  The control material is placed under a conventional pressure of about 5.5 GPa and a temperature of about 1,450 ° C. for about 9 minutes to produce a compact comprising a sintered PCD mass bonded to a tungsten carbide substrate. Formed.

  The compression body was substantially cylindrical in shape and had a diameter of about 16 mm. The compact included a layer of PCD integrally bonded onto a cobalt bonded tungsten carbide (WC) substrate, which was 2.2 mm thick. The diamond content of the PCD layer was about 92% by volume, with the remainder being cobalt and a small amount of precipitated phase such as WC. The diamond grains in the PCD thus produced have an average particle size of 34.7% by weight of the particles less than 5 microns and 40.4% by weight of the particles have an average size in the range of 5 to 10 microns. And a multimodal size distribution characterized by 24.9% by weight of the particles having an average particle size greater than 10 microns. The particle size distribution of the sintered PCD is different from the particle size distribution of the input particles due to the mutual crushing of the particles at high pressure in addition to the shift towards the coarser particle size that normally occurs during the sintering process.

Control and test compacts were analyzed. Both were found to contain PCD with the following phases present in the gap: Co ₃ Sn ₂ , Co ₃ SnC _0.7 , CoSn, Co, and WC. The main phase is Co ₃ SnC _0.7 , which is believed to play a major role in improving the thermal stability of PCD. Other phases were present in trace amounts.

  Image analysis was used to analyze the intergrowth of the diamond grains and the homogeneity of their spatial distribution within the PCD. A higher degree of diamond grain intergrowth was observed in the PCD of the test compact than in the control compact. The intergrowth and contact of the particles can be expressed as diamond grain proximity, with the average proximity of the test PCD compared to the average proximity of the control PCD of 59.2% (± 1.4%). It is 62.0% (± 1.9%), and the numerical value in parentheses is a standard deviation. Statistically, this absolute difference of 0.8% corresponds to a 95% confidence interval, so this absolute difference of 2.8% can be quite significant.

  The average interstitial mean free path of the test PCD was about 0.74 (± 0.62) microns compared to a control PCD average of 1.50 (± 2.53) μm.

More cobalt is present in the test PCD than in the control PCD, and additional cobalt is believed to have penetrated from the cobalt-containing substrate. This resulted in a test PCD having a higher content of CO ₃ SnCO _0.7 than that of the control PCD. Furthermore, the content of WC was higher in the test PCD and contained a large amount of recrystallized WC “plume” formation near the interface with the substrate.

The results of image analysis of the test materials are summarized in Tables 5 and 6. The data is not corrected for 3D with respect to 2D measurements obtained from image analysis of scanning electron micrographs. The parameters in the table have the same meaning as described in Example 1.

  Both the control and test samples were machined to form an insert suitable for rock boring, and this insert was subjected to wear testing, in this test to machine a granite block attached to a vertical turret milling device. Inserts were used. In this test, the granite block was machined through several passes and the size of the wear scar formed on the PCD as a result of wear on the granite was measured. The test PCD wear scar after 50 passes was about 30% less than that of the control PCD and continued at least 100 more passes at operating conditions.

  When producing some more test and control PCD samples, the quality of the test PCD was found to be even more consistent than the quality of the control PCD, and the failure rate was even lower.

  The use of the method according to the first aspect of the invention has been found to sinter thick PCD structures. Thicker PCD structures have greater strength than thinner PCD structures and everything else is the same.

(Example 4)
Several samples of Co-Sn based PCD sintered on a bonded carbide substrate were prepared. In each case, the tin powder was pre-reacted with the cobalt metal powder to produce a CoSn alloy / intermetallic compound with a specific atomic ratio of 1: 1. This pre-reacted source was then introduced into the green diamond powder mass by pre-synthesis mixing or in situ infiltration. A 1: 1 CoSn pre-reacted powder mixture was prepared by milling Co and Sn powder together in a planetary ball mill. The powder mixture was then heat treated in a vacuum furnace (600 ° C. to 800 ° C.) to produce a reacted CoSn material. The pre-reacted material was then further crushed / milled to break up aggregates and reduce particle size. The diamond powder size distribution had an average particle size of less than about 10 microns. A selected amount of this CoSn material (expressed as% by weight of the diamond powder mass) was then contacted with the unsintered diamond powder in an ultra high pressure furnace reaction volume. This is either as a separate powder layer adjacent to the diamond powder mass (which may penetrate the diamond during the ultra high pressure treatment after melting, ie in situ penetration), or before CoSn is introduced into the canister The material was mixed directly into the diamond powder mixture. The diamond powder / CoSn assembly was then placed adjacent to the bonded carbide substrate, thereby further increasing the metallic properties of the binder due to additional cobalt penetration from the bonded carbide substrate under ultra high pressure conditions. . The assembly was placed under a pressure of about 6.8 GPa and a temperature above the melting point of cobalt. Thus, a range of Co: Sn ratio binder systems and the resulting PCD material was produced.

(Example 5)
By blending the unimodal PCD test material with cobalt powder and diamond grains using a planetary ball mill and sintering the blended mixture at a pressure of 7.7 GPa and a temperature of 2,100 ° C. for about 60 seconds. Prepared. The diamond grains had an average size ranging from 3 microns to 6 microns. The weight ratio of cobalt to diamond in the blended powder mixture was 18:82. An independent unsupported sintered PCD sample with a diameter of 13.7 mm and a height of 4 mm was produced.

  The control PCD material has i) a cobalt to diamond weight ratio of 26:74 by introducing cobalt by conventional penetration from a bonded tungsten carbide substrate, and ii) a sintering pressure of 5.5 GPa and about 1 , Produced in the same manner as the test material except that a temperature of 450 ° C. was used.

Scanning electron micrographs of the polished sections of the sintered test PCD were obtained using backscattered electrons and image analysis was performed on the micrographs. The results of the image analysis of the test material are summarized in Tables 7 and 8, and these parameters have the same meaning as defined in Example 1.

  Test and control samples were formed into cut inserts by conventional processing and subjected to an abrasion test in which granite milling was performed. A cutting depth of 1 mm depth was used. The result of the abrasion test is the cut length, which is the distance of the granite that was milled before the cutter was deemed to have failed. The cut length of the test PCD is about 5,100 mm, which is significantly greater than the control PCD cut length, which is about 1,200 mm. This indicates that the abrasion resistance of the test PCD is several times greater than that of the control PCD.

Claims (20)

  A polycrystalline diamond (PCD) material comprising at least 88% by volume and up to 99% by volume diamond grains, with an average diamond grain proximity of greater than 60%.   The PCD material of claim 1, wherein the proximity of the diamond grains is at most 80%.   The PCD material according to claim 1 or 2, wherein the standard deviation of the diamond grain proximity is a maximum of 4% proximity. 4. The PCD material according to claim 1, having a volume of at least 0.5 mm ² .   5. The PCD material according to claim 1, wherein the diamond grains have a size distribution characteristic in which at least 50% of the grains have an average size greater than 5 microns.   The PCD material according to any one of claims 1 to 5, comprising diamond grains having a multimodal size distribution.   7. The PCD material according to any one of claims 1 to 6, comprising diamond grains having an average size of at most 15 microns.   8. The PCD material according to any one of claims 1 to 7, having an average interstitial mean free path of up to 1.5 microns.   The PCD material according to any one of claims 1 to 8, wherein the standard deviation of the interstitial mean free path is in the range of 0.05 microns to 1.5 microns.   10. PCD material according to any one of the preceding claims, having an average interstitial ECD size of at least 0.5 microns and at most 4 microns.   A filter material including a ternary carbide of the formula MxM′yCz, wherein M is at least one element selected from the group consisting of transition metals and rare earth metals, and M ′ is Al, Ga, In, Ge , Sn, Pb, Ti, Mg, Zn, and Cd, wherein x is in the range of 2.5 to 5.0 and y is in the range of 0.5 to 3.0 11. PCD material according to any one of claims 1 to 10, wherein z is in the range of 0.1 to 1.2.   12. The PCD of claim 11, wherein M is selected from the group consisting of Co, Fe, Ni, Mn, Cr, Pd, Pt, V, Nb, Ta, Ti, Zr, Ce, Y, La, and Sc. material.   13. PCD material according to any one of the preceding claims, having an oxidation onset temperature of at least 800 ° C.   14. A region adjacent to the surface comprising at most 2% by volume of diamond catalyst material and a region remote from the surface comprising more than 2% by volume of diamond catalyst material. The PCD material described in 1.   15. An insert comprising PCD material according to any one of the preceding claims, which is a drill bit for boring the ground bonded to a bonded carbide substrate.   Subjecting the agglomerates of diamond grains to a pressure treatment at a temperature high enough to melt the catalyst material in the presence of the diamond metal catalyst material and a pressure greater than 6.0 GPa; and sintering the diamond grains; Forming a PCD material, wherein the diamond grains in the agglomerates have an average size in which at least 50% of the particles have an average size greater than 5 microns and at least 20% of the particles range from 10 to 15 microns. 15. A method of making a PCD material according to any one of claims 1 to 14 having a size distribution characteristic having a size.   The method of claim 16, comprising subjecting the PCD material to further pressure treatment at a pressure of at least 2 GPa.   18. A method according to claim 16 or claim 17 comprising removing diamond metal catalyst material from a gap between the diamond grains and the PCD material.   19. A method according to any one of claims 16 to 18, comprising subjecting the PCD material to a heat treatment at a temperature of at least 500 <0> C for at least 5 minutes.   Introducing an additive material into the agglomerate, wherein the additive material comprises at least one element selected from V, Ti, Mo, Zr, W, Ta, Hf, Si, Sn, or Al. 20. The method according to any one of claims 16 to 19, comprising.

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