Iron gradients in polycrystalline diamond compacts, blanks, cutters, and cutting tools containing same, and methods of manufacture - Patents.com

Abstract

Polycrystalline diamond compacts, polycrystalline diamond blanks, polycrystalline diamond cutters, and tools incorporating them for cutting, milling, grinding, drilling, and other abrasive operations, particularly in metal cutting applications or drilling geological formations, include a diamond table having a gradient in iron content that increases with distance into the diamond table. The iron gradient increases resistance to wear in intermittent milling tests and the like. The present disclosure further relates to methods of manufacturing polycrystalline diamond compacts having a gradient in iron concentration within the diamond table, blanks and cutters including polycrystalline diamond compacts, and cutting tools incorporating such compacts, blanks, and cutters, as well as methods of cutting, milling, grinding, and drilling, particularly metalworking or rock drilling, using such compacts, blanks, cutters, cutting tools, and drill bits.

Description

[Technical field]

[0001] The present disclosure relates to abrasive structures, particularly polycrystalline diamond compacts, blanks, and cutters, and cutting tools that include them. More specifically, the present disclosure relates to polycrystalline diamond bodies that have a gradient in iron concentration within the diamond body, such that, for example, in the case of polycrystalline blanks, the amount of iron in the diamond body decreases from the outer surface to the interior of the mass toward the base. Such Fe-gradient diamond bodies can be embodied in a single unsupported compact, or can be supported by a base in blank or cutter embodiments. Each of the compacts, blanks, and cutters can be employed as cutting elements on a cutting tool. The present disclosure further relates to methods of manufacturing polycrystalline diamond compacts, blanks, and cutters with a gradient in iron concentration within the diamond table, cutting tools incorporating such compacts, blanks, and cutters, and methods of cutting, milling, grinding, and drilling, particularly metalworking or rock drilling, using such compacts, blanks, cutters, and cutting tools. [Background technology]

[0002] In the following discussion, certain structures and / or methods are described. However, nothing below should be construed as an admission that those structures and / or methods constitute prior art. Applicant expressly reserves the right to disclose that such structures and / or methods are not considered prior art with respect to the present invention.

[0003] Abrasive compacts consist of a mass of diamond or cubic boron nitride particles bonded into a coherent polycrystalline hard mass. In particular, polycrystalline diamond (PCD) particle-based abrasive compacts come in a variety of shapes and sizes, but are typically cylindrical and contain a mass of abrasive particles tightly attached or bonded to a substrate.

[0004] One application of abrasive compacts, particularly polycrystalline diamond-based abrasive compacts, is in cutting tools, for example for use in metalworking applications or for drilling geological formations. The compacts attached to a base form a blank and a cutter, either integrally formed during the manufacture of the coherent polycrystalline hard mass or subsequently placed together. The compacts, blanks, and cutters can be placed on the tool, for example, by brazing or integrally formed in casting, etc. In cutting, milling, grinding, and drilling applications, large forces are often exerted on the points or cutting edges of the working surface of the abrasive grain of the mass. As a result, cracks develop at or behind the cutting edges or contact points, which can propagate into and through the coherent polycrystalline hard mass. In addition, the heat generated by the various grinding operations can cause the coherent polycrystalline hard aggregate, and in particular its diamond particles, to firstly convert back diamond to carbon, which reduces the strength of the abrasive compact, and then cause thermal expansion, which can have a detrimental effect on the abrasive compact, resulting in cracking due to differences in the coefficients of thermal expansion between the various materials in the abrasive compact, in particular between the diamond material and any catalytic material within the coherent polycrystalline hard aggregate. Additionally, the abrasive compact can experience impact damage, resulting in large cracks propagating through the coherent polycrystalline hard aggregate, which can cause large losses of material, i.e., spalling or chipping.

[0005] It would therefore be advantageous to have a coherent polycrystalline hard mass, particularly a polycrystalline diamond compact, blank or cutter, having a composition and characteristics that have one or more of: low reverse transformation at high temperatures, low differences in coefficients of thermal expansion to reduce cracking due to thermal expansion, and improved toughness to minimize impact damage. Summary of the Invention

[0006] The present disclosure is directed to polycrystalline diamond compacts, polycrystalline diamond blanks, polycrystalline diamond cutters, and tools incorporating the same for cutting, milling, grinding, drilling, and other abrasive operations, particularly for use in metalworking applications or drilling geological formations, in which the diamond table has a gradient in iron content that increases with increasing distance into the bulk of the diamond table, which confers improved mechanical properties to the diamond table. Additional features and advantages will be set forth in the following description, and in part will be obvious from the description, or may be learned by practicing the invention. The objectives and other advantages of the present disclosure will be realized and attained by these structures and will be particularly pointed out in the written description and claims thereof, as well as in the accompanying drawings.

[0007] The present disclosure includes embodiments of polycrystalline diamond compacts that include a mass of crystalline diamond grains bound together by inter-diamond bonds to form a diamond body. The diamond body includes a plurality of inter-grain regions disposed between the bound crystalline diamond grains, and a cobalt-based catalytic material present in at least a portion of the plurality of inter-grain regions, such as in the case of a polycrystalline diamond blank, where an iron concentration gradient extends from the outer surface of the diamond body to the bulk interior of the diamond body toward the interface, i.e., the amount of iron in the diamond body decreases from the outer surface to the bulk interior toward the interface.

[0008] The present disclosure also includes embodiments of polycrystalline diamond blanks or cutters comprising a mass of crystalline diamond grains bonded together by inter-diamond bonds to form a diamond body and a hard metal substrate. The diamond body includes a plurality of inter-grain regions disposed between the bonded crystalline diamond grains and a cobalt-based catalytic material present in at least a portion of the plurality of inter-grain regions, and the diamond body is bonded to the hard metal substrate to form an interface. The iron concentration gradient within the diamond body extends from the interface to the interior of the mass of the diamond body. In such cases, the concentration of iron is lower at the interface and increases towards the outer surface.

[0009] In another aspect, embodiments of cutting tools, such as drill bits and drag bits, are disclosed. In the drill bit, an alloy body (including a front end, a shaft portion, and a rear end adapted to be mounted in a tool holder) has a polycrystalline diamond compact or blank attached to the front end. In the drag bit, a plurality of such polycrystalline diamond compacts and / or a plurality of such polycrystalline diamond cutters are disposed on and attached to the radially outwardly facing outer edges of a plurality of fins disposed along the outer surface of the front end of the drag bit body, each of the fins being separated from successive adjacent fins by a spirally formed flute extending rearward.

[0010] In another aspect, one embodiment of a cutting tool includes a first base and a tip attached to the seating surface of the first base. The tip includes a mass of crystalline diamond grains bonded together by inter-diamond bonds to form a diamond body, the diamond body including a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, a cobalt-based catalyst material present at least in a portion of the plurality of inter-grain regions, a second base formed of a hard metal, the diamond body bonded to the second base to form an interface, and an iron concentration gradient in the diamond body extending from the interface to the bulk interior of the diamond body. Here again, the iron concentration is greater at the outer surface than toward the bulk interior and is lowest adjacent to the interface. In an exemplary embodiment, the tip is attached to the first base by brazing the tip to the seating surface of the first base.

[0011] In another aspect, there is provided an embodiment of a method for producing a polycrystalline diamond compact comprising an assembly, the assembly comprising a diamond catalyst source, a layer of diamond feed in contact with the diamond catalyst source, and a heat-resistant vessel. The heat-resistant vessel comprises the diamond catalyst source and the layer of diamond feed, and the method comprises treating the assembly at a high temperature and pressure sufficient to sinter the diamond feed into a diamond body. The diamond feed comprises 90 to 99% by weight diamond particles and 1 to 10% by weight cobalt iron alloy, resulting in a diamond body comprising a mass of crystalline diamond grains bonded together by inter-diamond bonds, a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, a cobalt-based catalyst material present at at least a portion of the plurality of inter-grain regions, and an iron concentration gradient extending from an outer surface of the diamond body to the interior of the mass of the diamond body.

[0012] In another aspect, one embodiment of a method for manufacturing a polycrystalline diamond blank or cutter is provided, comprising forming an assembly, the assembly comprising a hard metal substrate having a composition comprising cemented carbide or cobalt cemented tungsten carbide (WC-Co), a layer of diamond feed in contact with a diamond catalyst source, and a heat-resistant vessel. The heat-resistant vessel comprises a diamond catalyst source and a layer of diamond feed, and the method subjects the assembly to a high temperature and pressure sufficient to sinter the diamond feed into a diamond body. The hard metal substrate is free of iron and has a composition comprising cemented carbide or cobalt cemented tungsten carbide (WC-Co). The diamond feed comprises 90 to 99 weight percent diamond particles, the diamond particles having an average diameter of 0.5 microns or more and 40 microns or less. The diamond feed also comprises 1 to 10 weight percent cobalt iron alloy, the cobalt iron alloy being Co. x Fe y where 0.6≦x≦0.8, 0.2≦y≦0.4, and x+y=1.0. High pressure, high temperature (HPHT) processing of the diamond feed results in a diamond body comprising a mass of crystalline diamond grains bonded together by inter-diamond bonds, a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, a cobalt-based catalytic material present in at least a portion of the plurality of inter-grain regions, and an iron concentration gradient extending from an outer surface of the diamond body into the mass of the diamond body.

[0013] In an exemplary embodiment, the diamond feed consists of 90 to 99% by weight diamond particles and the balance to 100% by weight cobalt iron alloy.

[0014] Other systems, methods, features, and advantages will be or become apparent to one of ordinary skill in the art upon examination of the following drawings and detailed description. All such additional systems, methods, features, and advantages are intended to be included within this description and the scope of this disclosure, and protected by the following claims. Nothing in this section should be construed as limiting the scope of those claims. Further aspects and advantages are discussed below in conjunction with embodiments of the disclosure. It will be understood that both the foregoing general description of the disclosure and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the disclosure as claimed.

[0015] The accompanying drawings, which are included to provide a further understanding of the invention, and which are incorporated in and constitute a part of this specification, illustrate implementations of the invention and, together with the description, serve to explain the principles of the disclosure. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 shows a schematic perspective view of a cylindrically shaped abrasive blank based on polycrystalline diamond (PCD) particles. [Diagram 2] FIG. 1 shows a schematic representation of an enlarged portion of a diamond body having crystalline diamond grains bonded together by inter-diamond bonds, a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, and a cobalt-based catalytic material present in at least a portion of the plurality of inter-grain regions. [Figure 3A] A cross-section of a polycrystalline diamond blank is depicted diagrammatically with enlarged area P1. [Figure 3B] Schematically depicting the iron gradient across the diamond table in site P1. [Figure 4]FIG. 1 is a scanning electron microscope (SEM) micrograph of a cross section of a portion of a polycrystalline diamond blank, with a portion of the base and a portion of the diamond table superimposed on the micrograph, resulting from energy dispersive X-ray spectroscopy (EDS) from a line scan across the diamond table. [Figure 5A] FIG. 11 is a second SEM micrograph of a cross-section of a portion of a polycrystalline diamond blank, the regions being areas mapped for compositional analysis by EDS area scan. [Figure 5B] 1 is a table showing the results from the compositional analysis. [Figure 6] 1 is a graph of Fe element content (in weight percent (wt%)) in the diamond table as a function of distance (in microns) from the interface for three samples of polycrystalline diamond cutters. [Figure 7] 1 is a graph of Fe element content (in weight percent (wt%)) in the diamond table as a function of distance (in microns) from the interface for three samples of polycrystalline diamond cutters. [Figure 8] 1 shows an example of a cutting tool used in the metalworking industry, in this case a drill bit, on which the polycrystalline diamond compact of the present invention is mounted. [Figure 9] 1 shows an example of a cutting tool used in the hole-drilling industry, in this case a drag bit, on which the polycrystalline diamond cutter of the present invention is mounted. [Figure 10] FIG. 2 is a graph showing results from intermittent milling tests on two inventive polycrystalline diamond blanks and one comparative polycrystalline diamond blank. [Figure 11A] 13A-13C illustrate additional examples of cutting tools that can be made from the disclosed blanks. [Figure 11B] 13A-13C illustrate additional examples of cutting tools that can be made from the disclosed blanks.

[0017] Throughout these drawings and the detailed description, unless otherwise stated, like drawing reference numbers should be understood to refer to like elements, features, and structures. The relative size and depiction of those elements may be exaggerated for clarity, presentation, and convenience. Also, for ease of viewing, in some instances, only some of the features that are pointed to in the figures are labeled with reference numbers. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] FIG. 1 shows a schematic perspective view of a cylindrically formed grinding blank 10 based on polycrystalline diamond (PCD) particles. The grinding blank is also called polycrystalline diamond blank (PDC). The blank 10 has a substrate 20 made of hard metal, alloy, or composite material, and most typically cemented carbide or cobalt cemented tungsten carbide (WC-Co), and a mass of polycrystalline diamond composite 30 (also called diamond table or diamond body) intimately attached or bonded to the substrate along an interface 40. In the mass of polycrystalline diamond composite 30, the diamond particle content is high, and there are many inter-diamond bonds, i.e., direct inter-particle bonds, between the diamond particles. A catalyst such as cobalt metal or its alloy is often present in the high pressure, high temperature (HPHT) manufacturing of the polycrystalline diamond cutter 10 as a diamond bond forming aid. The polycrystalline diamond blank 10 can then be machined to the desired shape, including machining to a specified outer diameter, height, and (optionally) adding any surface features such as chamfers or bevels. Chamfers or bevels are more typically found in polycrystalline diamond cutters as opposed to polycrystalline diamond blanks. All or a portion of the top surface 50 and side surface 60 can be the working surface of the polycrystalline diamond blank 10, i.e., the surface of the polycrystalline diamond blank 10 that contacts a workpiece during cutting, milling, grinding, or drilling.

[0019] The polycrystalline diamond composite mass 30 is often supported by being bonded to a substrate or support, such as a substrate of a hard metal such as cemented carbide, in which case the integrally formed structure of the polycrystalline diamond composite mass 30 and substrate is referred to herein as a polycrystalline diamond blank or blanks (for metalworking applications) or a polycrystalline diamond cutter or cutters (for geological formation drilling applications). Note, however, that in some instances the polycrystalline diamond composite mass 30 may be unsupported, i.e., without a substrate, in which case the polycrystalline diamond composite mass 30 is referred to herein as a polycrystalline diamond compact or compact.

[0020] In both the embodiment as polycrystalline diamond blank or polycrystalline diamond cutter and the embodiment as polycrystalline diamond compact, the diamond body is formed from a mass of crystalline diamond grains that are bonded together by inter-diamond bonds. FIG. 2 is a schematic representation of an enlarged portion of a diamond body 100. In the diamond body, crystalline diamond grains 110 are bonded together by inter-diamond bonds 120. The diamond body 100 includes a plurality of inter-grain regions 130 that are disposed between the bonded crystalline diamond grains 110. A cobalt-based catalyst material 140 is present in at least a portion of the plurality of inter-grain regions 130 and / or in a portion of each inter-grain region 130. As disclosed herein, optional processing may remove the metal catalyst from the inter-grain regions, and such inter-grain regions without the metal catalyst are also shown in FIG. 2.

[0021] In addition, the diamond body of the compact, blank, or cutter has an iron concentration gradient extending from the outer surface of the diamond body into the bulk of the diamond body. When resting on a substrate, such iron concentration gradient extends from the interface between the diamond body and the substrate. Typically, the iron concentration gradient varies from 0 to 0.1 wt. % Fe at the outer surface of the compact, or in the case of a blank, at the interface, to 0.7 to 1 wt. % Fe at a location within the diamond body at a distance of about 600 to 700 microns from the outer surface / interface. In some embodiments, the iron concentration gradient varies from 0 wt. % Fe, alternatively 0.01 to 0.1 wt. % Fe, at the outer surface (for a polycrystalline diamond compact) or at the interface (for a polycrystalline diamond blank or cutter) of the diamond body, to 0.7 to 0.9 wt. % Fe at a distance of 600 to 700 microns from the outer surface / interface. In other embodiments the iron concentration gradient varies from 0 wt% Fe, alternatively 0.01 to 0.1 wt% Fe at the outer surface (for polycrystalline diamond compacts) or interface (for polycrystalline diamond blanks or cutters) of the diamond body, to 0.3 to 0.4 wt% at a distance of 600 to 700 microns from the outer surface / interface.

[0022] Figure 3A illustrates a schematic cross-section of the blank 200 with an enlarged portion P1. Figure 3B illustrates a schematic iron gradient across the diamond table in portion P1. As shown in Figure 3B, the iron concentration 210 generally increases with distance from the interface 220 between the diamond table 230 and the substrate 240 (such as a sintered WC substrate) to the top surface 250 of the diamond table 230. In the schematic shown in Figure 3B, the iron concentration ([Fe]) is in arbitrary units (atomic units).

[0023] 4 is a scanning electron microscope (SEM) micrograph 300 of a cross section of a portion of a blank consistent with those disclosed herein. Micrograph 300 shows a portion of a base 310 and a portion of a diamond table 320. The base is tungsten carbide. Micrograph 300 has a magnification of 150X and the scale bar in the bottom margin is 100 microns.

[0024] Superimposed on the micrograph 300 of FIG. 4 are results from Energy Dispersive X-ray Spectroscopy (EDS). These results are from an EDS line scan across the diamond table 320 beginning at the substrate / diamond table interface 330 and extending toward the surface of the diamond table 320, typically toward a portion of the work surface, or alternatively toward the top surface 60. The EDS results graphically present the elemental content in the diamond table 320 as a function of distance (in microns) from the interface. The weight percentage (wt%) is on a logarithmic scale, extending from 0.0 wt% to 100 wt%, with the distance from the interface 330 extending from 0 to over 600 microns. The rightmost part of the figure is at a distance of 680 microns. The elemental contents shown in the EDS results are carbon (C) 340, cobalt (Co) 350, tungsten (W) 360, and iron (Fe) 370. Also shown is a curve fit 380 for the iron content 370. Since weight percent (wt%) is on a logarithmic scale, the curve fit 380 to the iron content 370 represents a linear gradient in iron content (Fe wt%) with distance from the interface 330. The experimentally found linear gradient in iron content shown in FIG. 4 is consistent with the iron concentration ([Fe]) 210 depicted diagrammatically in FIG. 3B.

[0025] In the micrograph 300 of FIG. 4, the carbon 340 content is from the diamond in the diamond table 320 and increases from about 60% by weight at or near the interface 330 at a distance greater than 100 microns, at an amount greater than 90% by weight, and then remains substantially constant. The cobalt 350 and tungsten 360 content in the diamond table 320 are swept from the base 310 to the diamond table 320 during the HPHT process, and are each at their maximum at the interface 330 at an amount of about 13% by weight for cobalt 350 and about 2.5% by weight for tungsten 360, before remaining substantially constant at a distance greater than 100 microns. In this sample, the base does not contain iron, and the iron 370 content is from iron present in the diamond feed used in the HPHT process. The iron content is also affected by the sweep of cobalt into the diamond table in that the iron is at least partially swept in with the cobalt. Thus, the iron content is lower at the interface 330 than at the inner portion of the diamond table 320. In Figure 4, the iron 370 content varies from about 0.0 wt% Fe at the interface, alternatively 0.01 to 0.1 wt% Fe, to about 0.8 wt% at a distance of 680 microns from the interface.

[0026] FIG. 5A is a second (SEM) micrograph 400 of a cross section of a portion of a blank consistent with those disclosed herein. The micrograph 400 has a magnification of 150X and a scale bar in the bottom margin of 250 microns. Eight regions are shown in the micrograph 400, which correspond to the regions sampled by area mapping for compositional analysis by EDS area scan. FIG. 5B is a table showing the results from the compositional analysis in the eight regions. The numbering of the "spectra" in the table of FIG. 5B corresponds to the numbering of the regions in FIG. 5A, and some details on the location of each of the regions (whether it is the base 402 or the diamond table 404 in FIG. 5A, and the distance to the interface 406 (annotated by a dotted line)) are shown in Table 1 below.

[0027] Table 1 - Information regarding Figures 5A and 5B TIFF0007667782000001.tif51170

[0028] From the results in FIG. 5B, it is observed that the substrate 402 has a composition of cobalt, tungsten, and carbon, which is consistent with a substrate of cobalt tungsten carbide (Co-WC). Furthermore, as seen from spectra 7 and 8, both of which are within the substrate 402, the composition of substrate 402 does not include iron. From the results in FIG. 5B, it is also observed that the amount of iron in the diamond table 404 varies from 0.08% by weight (see spectrum 5 corresponding to region 5) to 0.70% by weight (see spectrum 1 corresponding to region 1). This change in the amount of iron in the diamond table occurred over a distance of about 630 microns, with an average change in iron as a function of distance from the interface of about 0.001% by weight / micron.

[0029] As described herein, the iron concentration gradient, i.e., the profile or change in the amount of iron in the diamond table, changes linearly from the outer surface of the diamond body (for polycrystalline diamond compacts) or from the interface (for polycrystalline diamond blanks or polycrystalline diamond cutters) to the bulk of the diamond body. It has further been found that the slope of the iron concentration gradient changes with the change in the average grain size of the crystalline diamond grains in the diamond feed. Figures 6 and 7 are graphs of the Fe element content (in weight percent (wt%)) in the diamond table as a function of the distance (in microns) from the interface for three samples of polycrystalline diamond blanks (sample 1, sample 2, and sample 3).

[0030] In FIG. 6, both Sample 1 (square, shown at 510 with linear curve fit 520) and Sample 2 (circle, shown at 530 with linear curve fit 540) used diamond feed with crystalline diamond grains having an average grain size of 0.5 to 3 microns. In FIG. 7, Sample 2 from FIG. 6 (circle, shown at 530 with linear curve fit 540) is represented and a new Sample 3 (triangle, shown at 550 with linear curve fit 560) is presented. Sample 3 used diamond feed with crystalline diamond grains having an average grain size of 30 microns. Thus, the average grain size for Sample 3 was 10x different compared to Samples 1 and 2.

[0031] Based on the curve fit 520, the Fe element content in the diamond table for Sample 1 varied from about 0 wt% (at the interface) to about 0.74 wt% at a distance from the interface of 660 microns. Based on the curve fit 540, the Fe element content in the diamond table for Sample 2 varied from 0 wt% (at the interface) to 0.87 wt% at a distance from the interface of 700 microns. Based on the curve fit 560, the Fe element content in the diamond table for Sample 3 varied from about 0 wt% (at the interface) to about 0.37 wt% at a distance from the interface of 700 microns.

[0032] For each of Sample 1, Sample 2, and Sample 3, the iron composition increased monotonically from the interface (at about zero weight percent) into the bulk diamond table. Furthermore, if all of the parameters, including grain size, were the same, the iron concentration gradient was the same (Sample 1 compared to Sample 2), indicating that the iron concentration gradient was reproducible. However, if all of the parameters were the same between samples and only the average grain size differed, the iron concentration gradient was different (Sample 3 compared to Samples 1 and 2). For the samples shown in FIG. 7, increasing the average grain size by a factor of 10 resulted in less than half the slope of the iron concentration gradient (compared to the slope for the samples with smaller grain sizes).

[0033] Although Figures 6 and 7 report results from samples produced using diamond feeds with crystalline diamond grains having an average grain size of 3 microns or 30 microns, other embodiments of polycrystalline diamond compacts, polycrystalline diamond blanks, and polycrystalline diamond cutters may be produced using diamond feeds with crystalline diamond grains having other average grain sizes. For example, the crystalline diamond grains may have an average grain size of 1 to 40 microns, alternatively 3 to 40 microns, alternatively 25 to 30 microns, alternatively 1 to 25 microns, alternatively 3 to 25 microns, alternatively 1.5 to 3.0 microns. As is evident from Figures 6 and 7, the selection of the average grain size may affect the iron concentration gradient in the product as produced, and the average grain size may be selected to achieve a desired iron concentration gradient.

[0034] It is believed that varying other parameters will also vary the iron concentration gradient. Examples of other parameters that can be varied to affect the iron concentration gradient and direction include HPHT (high pressure and high temperature) settings, grain size distribution (PSD), total metal content in the carbide matrix, total metal content in the diamond table, and sweep direction, i.e., metal sweep vertically from the carbide interface to the PCD, horizontally from the refractory cup wall holding the PCD, or vertically from the cup end via an external metal sweep source.

[0035] Polycrystalline diamond compacts and blanks are widely used in cutting, milling, grinding, drilling and other abrasive operations, as well as metal cutting applications, and polycrystalline diamond compacts and cutters are widely used in geological formation drilling applications.

[0036] Tools used in the metalworking industry, such as drill bits, may incorporate polycrystalline diamond compacts or polycrystalline diamond blanks. Shown in FIG. 8 are three example drill bits, a perspective view of a solid shaft round tool 600a, a side view of a helical fluted drill bit 600b, and a perspective view of a helical fluted drill bit 600c. Each of the drill bits includes an alloy body 610, for example made of tungsten carbide. The alloy body 610 includes a front end 620, a shaft portion 630, and a rear end 640 adapted to be mounted in a tool holder. The front end 620, the shaft portion 630, and the rear end 640 are arranged consecutively along a longitudinal axis 650 of the body. The drill bit includes a polycrystalline diamond compact 660 attached to the front end 620. The polycrystalline diamond compact 660 may be attached by brazing or some other attachment technique, or may be integrally formed with the alloy body 610. Helical flutes 670 may optionally be provided, as seen by the example round tools 600b and 600c, which are used, for example, for machining aluminum, titanium and their alloy workpieces, as well as composite workpieces, in the aerospace industry.

[0037] Also, tools used in the drilling industry, such as drag bit 700 (see FIG. 9), often incorporate a plurality of polycrystalline diamond cutters or compacts. In an exemplary embodiment, drag bit 700 has an alloy body 720 including a leading end 730, a shoulder region 740, and a threaded trailing end 750, disposed consecutively along a longitudinal axis 760 of the body 720. Drag bit 700 has a plurality of fins 770 (sometimes referred to as blades) disposed along an outer surface of leading end 730. Each of the fins 770 is separated from successive adjacent fins 770 by helically formed flutes 780 extending rearward. Additionally, disposed along the outer edge region of the fins 770 are a plurality of polycrystalline diamond cutters 710. Although not shown in FIG. 9, the polycrystalline diamond cutters 710 may be replaced by polycrystalline diamond compacts. In each example, the diamond table, whether a polycrystalline diamond cutter or a polycrystalline diamond compact, has the characteristics and properties described herein including, for polycrystalline diamond cutters, an iron concentration gradient within the diamond body extending from the interface into the bulk of the diamond body, and for polycrystalline diamond compacts, an iron concentration gradient extending from the outer surface of the diamond body into the bulk of the diamond body.

[0038] Intermittent milling tests were conducted using a face milling machine and an Al 6% Si alloy workpiece. A polycrystalline diamond blank sample having the characteristics and properties described herein, including an iron concentration gradient within the diamond body extending from the interface into the bulk of the diamond body, was tested in the intermittent milling tests. A polycrystalline diamond blank sample without an iron concentration gradient within the diamond body extending from the interface into the bulk of the diamond body was used as a control in the intermittent milling tests. Details of the tool test conditions for the intermittent milling tests are shown in Table 2.

[0039] Table 2 - Detailed tool test conditions for intermittent milling tests TIFF0007667782000002.tif56170

[0040] The intermittent milling test was performed for 330 passes, after which the samples were removed from the milling test and the flank wear was measured using an optical microscope. Figure 10 is a graph 800 showing the results from the intermittent milling test. In Figure 10, the Y axis shows the tool wear for (a) two polycrystalline diamond tools 810, 820 of the present invention with an iron concentration gradient in the diamond body extending from the interface to the bulk of the diamond body, and (b) a comparative polycrystalline diamond blank tool insert 830 without an iron concentration gradient in the diamond body. The polycrystalline diamond blank tool inserts 810, 820 of the present invention, as well as the tool without an Fe gradient, were manufactured using the same grade of diamond feed with crystalline diamond grains having an average grain size of 0.5 to 3 microns. The results in Figure 10 for the polycrystalline diamond tools 810 and 820 of the present invention are 24 to 26 microns, and the results in Figure 10 for the comparative polycrystalline diamond tool 830 are 95 microns.

[0041] 11A and 11B show schematic diagrams of additional examples of cutting tools that may be made incorporating the disclosed blanks. These cutting tool examples are shown in the form of a polycrystalline diamond blank 900 (sometimes referred to as a chip) and a cutting tool 970 having at least a portion formed from the polycrystalline diamond blank 900. For example, the polycrystalline diamond blank 900 shown includes a substrate 920 formed from a material such as tungsten carbide, and a diamond body 910 including an outer working layer 930 and an intermediate layer 940 disposed therebetween. The diamond body 910, typically the intermediate layer 940, is bonded to the substrate 920. Preferably, the outer working layer 930 will have a thickness between 0.4 mm and 0.6 mm. In the example shown, the interface 950 of the polycrystalline diamond blank 900 between the diamond body 910 and the substrate 920 is not planar, but other interface geometries and surfaces, including planar, may be used. In the example shown, the interface 950 includes arches that form the corrugated surface of the base 920, preferably having a height between 0.4 and 0.6 mm. To maintain sufficient spacing between the arches 960 and the outer working layer 930, the intermediate layer 940 should be at least 0.15 to 0.2 mm at its thinnest point (at the peak of the corrugated surface), and typically between 0.5 and 0.6 mm at its thickest point. FIG. 11B shows an example of a cutting tool 900, a tip that is attached to the base 960 and forms a cutting tool insert 970. The tip may be attached, for example, by brazing the tip to a seating surface of the base 960. Optional mounting features, such as a hole 980 extending from a first side of the cutting tool to a second side of the cutting tool insert 970, may be configured to receive a fastener, such as a screw, for mounting the cutting tool insert 970 to a processing tool, such as a milling tool (not shown). In Figures 11A and 11B, the polycrystalline diamond blank 900, i.e., the tip, is triangular in shape, although other geometries may be used, including circular, oval, and polygonal.

[0042] In particular, it is noted that the properties, images, and results associated with Figures 4, 5A-5B, 6-7, and 10 are for polycrystalline diamond blanks. However, similar results for the composition and compositional analysis of the diamond table would be expected to be obtained for polycrystalline diamond compacts. In each case, the iron content is determined from the surface of the diamond body into the bulk of the diamond body. For the case of polycrystalline diamond blanks, the surface coincides with the interface between the diamond table and the substrate, and for the case of polycrystalline diamond compacts, the surface is the outer surface from which the HPHT sweep occurs and from which the diamond table is assembled during HPHT processing. Additionally, the considerations and results for polycrystalline diamond blanks are also applicable and applicable to polycrystalline diamond cutters.

[0043] Generally, the polycrystalline diamond compacts, polycrystalline diamond blanks, and diamond tables of the polycrystalline diamond cutters disclosed herein can be formed by sintering diamond particles under high pressure, high temperature (HPHT) conditions in the presence of a metal catalyst (cobalt, Co, etc.). The metal catalyst can come from an independent source, such as a metal catalyst powder mixed with the diamond particles or in a layer adjacent to the diamond particles, or from a substrate material described below. Typical HPHT conditions include a pressure of about 4 GPa or higher and a temperature of about 1400°C or higher. Typically, under HPHT processing conditions, the binder material present in the independent source or in a substrate (typically a sintered carbide substrate) located adjacent to the diamond powder is melted and swept into the diamond mass. If a substrate is present, the binder material of the substrate can act as a metal catalyst in the diamond powder. In the presence of the metal catalyst, the diamond crystals bond together in inter-diamond bonds by a dissolution precipitation process to form a sintered compact, in which the polycrystalline diamond mass, i.e., the diamond table, is attached to the substrate (if present) to form the substrate. The presence of a metal catalyst promotes the formation of diamond-diamond bonds and, where applicable, the adhesion of the diamond table to the substrate.

[0044] In certain embodiments, diamond particles are included within the diamond feed. The diamond feed comprises 90 to 99% by weight of diamond particles and 1 to 10% by weight of cobalt iron alloy. The cobalt iron alloy is homogeneously distributed in the diamond feed, for example, by ball milling the diamond feed with both the diamond particles and the cobalt iron alloy. In some embodiments, the diamond particles within the diamond feed have an average diameter of 3 microns or 30 microns. In other embodiments, the diamond particles within the diamond feed have other average diameters. For example, the diamond particles may have an average diameter of 1 to 40 microns, alternatively 3 to 40 microns, alternatively 25 to 30 microns, alternatively 1 to 25 microns, alternatively 3 to 25 microns, alternatively 1.5 to 3.0 microns. In alternative embodiments, the average diameter may be unimodal or multimodal.

[0045] In some embodiments, the cobalt-iron alloy is Co x Fe y where 0.6≦x≦0.8, 0.2≦y≦0.4, and x+y=1.0. Alternatively, the cobalt-iron alloy may be Co x Fe y In yet another alternative embodiment, the cobalt-iron alloy is Co x Fe y where x=0.7 and y=0.3.

[0046] The diamond feed is used to form an assembly, which then undergoes HPHT treatment at high temperature and pressure sufficient to sinter the diamond feed into a diamond body. The assembly includes a diamond catalyst source and a layer of diamond feed in contact with the diamond catalyst source contained within a heat-resistant container. Forming the assembly continues by placing a cap over the contents of the heat-resistant container and sealing it, such as by crimping.

[0047] When forming a polycrystalline diamond compact, the diamond catalyst source can be a metal catalyst powder mixed with diamond particles or a layer of metal catalyst powder adjacent to diamond particles. An example of a metal catalyst powder has a Co-based composition and does not contain iron. A specific iron-free Co-based composition suitable for use as a metal catalyst powder for forming the disclosed polycrystalline diamond compact is cemented carbide or cobalt cemented tungsten carbide (WC-Co) with about 0.1 to 5 weight percent feed of metallic cobalt.

[0048] When forming polycrystalline diamond blank or polycrystalline diamond cutter, diamond catalyst source can be a substrate material that is adjacent to diamond grains.An example of substrate material has a Co-based composition and does not contain iron.A specific Co-based composition that is suitable for use as substrate for forming the disclosed polycrystalline diamond blank or cutter is a substrate of cemented carbide or cobalt cemented tungsten carbide (WC-Co), with cobalt content in the substrate ranging from 5 to 15% by weight.

[0049] Metal catalysts remaining in the diamond table after the HPHT sintering process may impair the performance of the polycrystalline diamond when used in cutting or machining applications or when drilling underground geological formations. Therefore, metal catalysts remaining in the diamond table after the HPHT sintering process may be optionally removed in a subsequent leaching process. In the leaching process, at least a portion of the diamond body is exposed to an acid suitable for dissolving metal catalysts, such as aqua regia (a mixture of nitric acid and hydrochloric acid, most preferably in a molar ratio of 1:3). The catalytic material in the portion of the diamond body exposed to the acid is removed by the leaching process, leaving an intergrain region substantially free of catalytic material at the acid leached portion of the diamond body. As known to those skilled in the art, at least partial removal of catalytic material may provide the polycrystalline diamond material with improved thermal stability, which may also beneficially affect the wear resistance of the polycrystalline diamond material. If there is an acid leached portion of the diamond body, it extends from the working surface into the bulk of the diamond body.

[0050] While the present invention has been described in relation to embodiments thereof, those skilled in the art will appreciate that additions, deletions, modifications, and substitutions not specifically described herein may be made without departing from the spirit and scope of the invention as defined in the appended claims. For example, although described in relation to fissile fuel material, nuclear reactors, and associated components, the principles, compositions, structures, features, configurations, and processes described herein are also applicable to other materials, other compositions, other structures, other features, other configurations, and other processes, as well as their manufacture and to other reactor types.

[0051] With respect to any use of substantial plural and / or singular forms herein, a person of ordinary skill in the art will be able to convert from the plural to the singular and / or from the singular to the plural as appropriate to the context and / or application. The various permutations of the singular / plural forms have not been expressly set forth herein for the sake of clarity.

[0052] The subject matter described herein sometimes depicts different components contained within or associated with different other components. It will be understood that such depicted architectures are merely exemplary, and in fact many other architectures may be implemented to achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Thus, any two components combined herein to achieve a particular functionality can be viewed as being "associated" with one another such that the desired functionality is achieved, regardless of architecture or intermediate components. Similarly, any two components so associated can also be viewed as being "operably connected" or "operably coupled" with one another to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable" with one another to achieve the desired functionality. Specific examples of what can be operably coupled include, but are not limited to, physically coupleable and / or physically interacting components, and / or wirelessly interactable and / or wirelessly interacting components, and / or logically interacting and / or logically interacting components.

[0053] In some examples, one or more components may be referred to herein as being "configured to," "configured by," "configurable to," "operable / operative to," "adapted / adaptable," "able to," "conformable / conformed to," etc. Those skilled in the art will appreciate that such terms (e.g., "configured to") can generally encompass components in an active state and / or components in an inactive state and / or components in a standby state, unless the context requires otherwise.

[0054] While particular aspects of the subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based on the teachings herein, changes and modifications may be made that do not depart from the subject matter described herein and its broader aspects, and therefore, the appended claims are intended to encompass within their scope all such changes and modifications as are within the spirit and scope of the subject matter described herein. In general, those skilled in the art will understand that the terms used herein, and particularly in the appended claims (e.g., the body of the claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to", the term "having" should be interpreted as "having at least", the term "includes" should be interpreted as "includes but is not limited to", etc.). It will be further understood by those skilled in the art that where the recitation of a particular number of introduced claims is intended, such intent will be expressly recited in those claims and, absent such recitation, there is no such intent. For example, as an aid to understanding, the claims appended below may include the use of the phrases "at least one" and "one or more" as preambles to introduce the recitation of the claims.However, the use of such phrases should not be understood as implying that the introduction of a claim statement by the indefinite article "a" or "an" limits any particular claim that includes the claim statement so introduced to a claim that includes only one such statement, even if that claim includes the preface phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should typically be interpreted to mean "at least one" or "one or more"). The same is true for the use of definite articles used to introduce claim statements. In addition, even if a particular number of claims is explicitly recited, one of ordinary skill in the art will understand that such recitation should typically be interpreted to mean at least the recited number (e.g., the mere recitation of "two statements," without other modifiers, typically means at least two statements, or two or more statements). Furthermore, in those instances where a conventional expression similar to "at least one of A, B, and C, etc." is used, such a structure is generally intended in the sense that one of ordinary skill in the art would understand that conventional expression (e.g., "a system having at least one of A, B, and C" would include, but is not limited to, a system having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.).In those instances where a conventional expression similar to "at least one of A, B, or C, etc." is used, such a structure is generally intended in the sense that one of ordinary skill in the art would understand that conventional expression (e.g., "a system having at least one of A, B, or C" would include, but is not limited to, a system having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Typically, one of ordinary skill in the art will further understand that disjunctions and / or phrases presenting two or more alternative terms should be understood to be contemplated in the specification, claims, or drawings, the possibility of including one of those terms, either of those terms, or both of those terms, unless the context dictates otherwise. For example, the phrase "A or B" will typically be understood to include the possibilities of "A" or "B" or "A and B."

[0055] With respect to the appended claims, those skilled in the art will appreciate that the operations described herein may generally be performed in any order. Also, while various operational flows have been presented in a single or multiple orders, it should be understood that these various operations may be performed in other orders than those shown herein, or may be performed simultaneously. Examples of such alternative orders may include overlapping, alternating, interrupted, reordered, incremental, preliminary, auxiliary, simultaneous, inverted, or other variant orders, unless the context dictates otherwise. Moreover, terms such as "responsive to," "related to," or other past tense adjectives are generally not intended to exclude such variants, unless the context dictates otherwise.

[0056] Those skilled in the art will appreciate that the foregoing specific example processes and / or devices and / or techniques are representative of more general processes and / or devices and / or techniques that are taught elsewhere in this specification and / or elsewhere in this application, such as in the claims filed herewith.

[0057] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will occur to those of ordinary skill in the art. The various aspects and embodiments disclosed herein are intended to be illustrative, and not limiting, within the scope and spirit of the claims that follow.

[0058] The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting, as other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.

[0059] Those skilled in the art will appreciate that the components (e.g., acts), devices, objects, and the accompanying discussion described herein are used as examples for conceptual clarity, and that various configurational variations are possible. As a result, as used herein, the specific examples set forth herein and the accompanying discussion are intended to be representative of their more general classes. In general, the use of any specific example is intended to be representative of its class, and the absence of the inclusion of a particular component (e.g., act), device, or object should not be considered limiting.

Claims

1. An unsupported polycrystalline diamond compact, comprising: A diamond table having a top surface and a side surface as working surfaces, an outer surface as a non-working surface, and an interior of a mass, the diamond table comprising: a mass of crystalline diamond grains bonded together by inter-diamond bonds to form said diamond table, said diamond table including a plurality of inter-grain regions located between said bonded crystalline diamond grains; a cobalt-based catalytic material present in at least a portion of the intergrain regions; an iron concentration gradient extending from the outer surface of the diamond table to the interior of the mass of the diamond table; 1. An unsupported polycrystalline diamond compact comprising:

2. 2. An unsupported polycrystalline diamond compact as claimed in claim 1, wherein the iron concentration gradient varies linearly from the outer surface of the diamond table to the interior of the mass of the diamond table.

3. 2. The unsupported polycrystalline diamond compact of claim 1, wherein the iron concentration gradient is 0 to 0.01 wt. % Fe at the outer surface of the diamond table and 0.7 to 0.9 wt. % Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

4. 2. An unsupported polycrystalline diamond compact according to claim 1, wherein the crystalline diamond grains have an average grain size of from 0.5 to 3 microns.

5. 2. An unsupported polycrystalline diamond compact as claimed in claim 1, wherein the iron concentration gradient is 0.01 to 0.1 wt% Fe at the outer surface of the diamond table and 0.7 to 0.9 wt% Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

6. 2. The unsupported polycrystalline diamond compact of claim 1, wherein the iron concentration gradient is 0 to 0.01 wt. % Fe at the outer surface of the diamond table and 0.3 to 0.4 wt. % Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

7. 2. An unsupported polycrystalline diamond compact according to claim 1, wherein the crystalline diamond grains have an average grain size of from 25 to 30 microns.

8. 2. An unsupported polycrystalline diamond compact as claimed in claim 1, wherein the iron concentration gradient is 0.01 to 0.1 wt% Fe at the outer surface of the diamond table and 0.3 to 0.4 wt% Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

9. A polycrystalline diamond blank comprising: A diamond table having a top surface and a side surface as working surfaces, an outer surface as a non-working surface, and an interior of a mass, the diamond table comprising: a mass of crystalline diamond grains bonded together by inter-diamond bonds to form said diamond table, said diamond table including a plurality of inter-grain regions located between said bonded crystalline diamond grains; a cobalt-based catalytic material present in at least a portion of the intergrain regions; a hard metal base, the diamond table being bonded to the hard metal base to form an interface; an iron concentration gradient within the diamond table extending from the interface into the interior of the mass of the diamond table; A polycrystalline diamond blank comprising:

10. A polycrystalline diamond blank according to claim 9, wherein the hard metal substrate has a composition comprising cemented carbide or cobalt cemented tungsten carbide (WC-Co).

11. A polycrystalline diamond blank according to claim 9, wherein the hard metal substrate has an iron-free composition.

12. 10. A polycrystalline diamond blank according to claim 9, wherein the iron concentration gradient varies linearly from an outer surface of the diamond table to the interior of the mass of the diamond table.

13. 10. A polycrystalline diamond blank as claimed in claim 9, wherein the iron concentration gradient is 0 to 0.01 wt% Fe at the outer surface of the diamond table which is bonded to the hard metal substrate forming the interface, and 0.7 to 0.9 wt% Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

14. 10. A polycrystalline diamond blank according to claim 9, wherein the crystalline diamond grains have an average grain size of from 0.5 to 3 microns.

15. 10. A polycrystalline diamond blank as claimed in claim 9, wherein the iron concentration gradient is 0.01 to 0.1 wt% Fe at the outer surface of the diamond table which is bonded to the hard metal substrate forming the interface, and 0.7 to 0.9 wt% Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

16. 10. A polycrystalline diamond blank as claimed in claim 9, wherein the iron concentration gradient is 0% by weight Fe at the outer surface of the diamond table which is bonded to the hard metal substrate forming the interface, and 0.3 to 0.4% by weight at a distance of 600 to 700 microns from the outer surface of the diamond table.

17. 10. A polycrystalline diamond blank according to claim 9, wherein the crystalline diamond grains have an average grain size of 25 to 30 microns.

18. 10. A polycrystalline diamond blank as claimed in claim 9, wherein the iron concentration gradient is 0.01 to 0.1 wt% Fe at the outer surface of the diamond table which is bonded to the hard metal substrate forming the interface, and 0.3 to 0.4 wt% Fe at a distance of 600 to 700 microns from the outer surface of the diamond table.

19. an alloy body including a front end, a shaft portion, and a rear end adapted to be mounted on a tool holder, the front end, the shaft portion, and the rear end being disposed consecutively along a longitudinal axis of the alloy body; an unsupported polycrystalline diamond compact according to claim 1 attached to said front end; Metal cutting tools.

20. an alloy body including a front end, a shaft portion, and a rear end adapted to be mounted on a tool holder, the front end, the shaft portion, and the rear end being disposed consecutively along a longitudinal axis of the alloy body; A polycrystalline diamond blank according to claim 9 attached to said front end; Metal cutting tools.

21. forming an assembly including a source of diamond catalyst, a layer of diamond feed in contact with said source of diamond catalyst, and a heat resistant vessel containing said source of diamond catalyst and said layer of diamond feed; treating the assembly at a high temperature and pressure sufficient to sinter the diamond feed into a diamond body; 1. A method for producing a polycrystalline diamond compact, comprising: the diamond feed comprising 90 to 99 weight percent diamond particles and 1 to 10 weight percent cobalt-iron alloy; the diamond body comprises a mass of crystalline diamond grains bonded together by inter-diamond bonds, a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, a cobalt-based catalytic material present in at least a portion of the plurality of inter-grain regions, and an iron concentration gradient extending from an outer surface of the diamond body into the mass of the diamond body. A method for producing a polycrystalline diamond compact.

22. The cobalt-iron alloy has the composition Co ｘ Fe ｙ 22. The method of claim 21 , wherein 0.6≦x≦0.8, 0.2≦y≦0.4, and x+y=1.

0.

23. The cobalt-iron alloy has the composition Co ｘ Fe ｙ 23. The method of claim 22, wherein 0.68≦x≦0.72, 0.28≦y≦0.32, and x+y=1.

0.

24. The cobalt-iron alloy has the composition Co ｘ Fe ｙ 24. The method of claim 23, wherein x=0.7, y=0.3, and x+y=1.

0.

25. 22. The method of claim 21, wherein the diamond particles have an average diameter of from 1 micron to 40 microns.

26. 26. The method of claim 25, wherein the average diameter of the diamond particles is between 3 microns and 40 microns.

27. 26. The method of claim 25, wherein the average diameter of the diamond particles is from 1 micron to 25 microns.

28. 27. The method of claim 26, wherein the average diameter of the diamond particles is between 3 microns and 25 microns.

29. 26. The method of claim 25, wherein the average diameter of the diamond particles is greater than or equal to 1.5 microns and less than or equal to 3.0 microns.

30. 22. The method of claim 21, wherein the diamond catalyst source is a hard metal matrix having an iron-free composition, including cemented carbide or cobalt cemented tungsten carbide (WC-Co).

31. 22. The method of claim 21, wherein the diamond catalyst source is a powder having an iron-free composition comprising cemented carbide or cobalt cemented tungsten carbide (WC-Co).

32. Forming the assembly includes: placing said diamond catalyst source in said heat resistant vessel; forming a layer of said diamond feed in said heat resistant vessel in contact with said diamond catalyst source; placing a cap over the contents of the heat resistant container and sealing the cap; 22. The method of claim 21 , comprising:

33. 22. The method of claim 21 , wherein the first portion of the diamond body extends from a working surface into the interior of the mass of the diamond body.

34. forming an assembly including a hard metal substrate having an iron-free composition including cemented carbide or cobalt-cemented tungsten carbide (WC-Co), a layer of diamond feed in contact with a source of diamond catalyst, and a heat-resistant vessel having the iron-free hard metal substrate, the source of diamond catalyst, and the layer of diamond feed; treating the assembly at a high temperature and pressure sufficient to sinter the diamond feed into a diamond body; 1. A method for producing a polycrystalline diamond blank, comprising: the diamond feed comprises 90 to 99 weight percent diamond particles and 1 to 10 weight percent cobalt iron alloy having a composition Co x Fe y , where 0.6≦x≦0.8, 0.2≦y≦0.4, and x+y=1.0; The average diameter of the diamond particles is equal to or greater than 1 micron and equal to or less than 40 microns; the diamond body comprises a mass of crystalline diamond grains bonded together by inter-diamond bonds, a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, a cobalt-based catalytic material present in at least a portion of the plurality of inter-grain regions, and an iron concentration gradient extending from an outer surface of the diamond body into the mass of the diamond body. A method for producing a polycrystalline diamond blank.

35. 35. The method of claim 34, wherein the diamond particles have an average diameter of at least 3 microns and not more than 25 microns.

36. 36. The method of claim 35, wherein the average diameter of the diamond particles is greater than or equal to 1.5 microns and less than or equal to 3.0 microns.

37. The cobalt-iron alloy has the composition Co ｘ Fe ｙ 35. The method of claim 34, wherein 0.68≦x≦0.72, 0.28≦y≦0.32, and x+y=1.

0.

38. The cobalt-iron alloy has the composition Co ｘ Fe ｙ 38. The method of claim 37, wherein x=0.7, y=0.3, and x+y=1.

0.

39. 35. The method of claim 34, further comprising ball milling the diamond feed prior to forming the assembly.

40. 33. The method of claim 32, further comprising placing a cap over the contents of the heat-resistant container and sealing the cap prior to processing the assembly.

41. The first foundation; a chip attached to a seat of the first substrate; 1. A metal cutting tool comprising: The chip comprises: a diamond table having a top surface and a side surface as working surfaces, an outer surface as a non-working surface, and an interior of the block; The diamond table is a mass of crystalline diamond grains bonded together by inter-diamond bonds to form a diamond table, the diamond table including a plurality of inter-grain regions located between the crystalline diamond grains to which they are bonded; a cobalt-based catalytic material present in at least a portion of the intergrain regions; a second substrate formed from a hard metal, the diamond table being bonded to the second substrate to form an interface; and an iron concentration gradient within the diamond table extending from the interface into the interior of the mass of the diamond table; Metal cutting tools.

42. 42. The metal cutting tool of claim 41, wherein the diamond table includes an outer working layer and an intermediate layer, the intermediate layer disposed between the outer working layer and the interface formed between the diamond table and the second substrate.

43. 43. The metal cutting tool of claim 42, wherein a surface of the second substrate forming the interface is corrugated to form a plurality of protrusions, and the intermediate layer is configured to be inserted into the plurality of protrusions of the second substrate and bonded to the second substrate.

44. 42. The metal cutting tool of claim 41, wherein the tip is attached to the first base by brazing the tip to the seating surface of the first base.

45. 42. The metal cutting tool of claim 41, wherein the tip is circular or elliptical.

46. 42. The metal cutting tool of claim 41, wherein the tip is polygonal.

Images