KR20120006017A - Polycrystalline diamond element - Google Patents

Abstract

One embodiment of a PCD member includes an embodiment of a PCD member bonded with a cemented carbide substrate at an interface. The PCD member has internal diamond surfaces that define the gaps. The PCD member further includes a work surface, and a low melting point region adjacent to the work surface, wherein the gaps are at least partially filled with a low melting metal material having a melting point of less than about 1,300 ° C. at atmospheric pressure, or less than about 1,200 ° C. at atmospheric pressure. do. The PCD member comprises an intermediate region wherein the gaps in the intermediate region are at least partially filled by the catalyst material for diamond.

Description

Polycrystalline Diamond Member {POLYCRYSTALLINE DIAMOND ELEMENT}

The present invention relates to polycrystalline diamond (PCD) members, in particular non-limiting pavement, rock formation treatment or decomposition, or attack tools and cutters such as picks that can be used in the mining mine, tunneling, construction, and oil and gas industries. A PCD member suitable for use in picks, rotary drill bits and the like.

The cutter insert for drill bits used for mining may comprise a layer of polycrystalline diamond (PCD) bonded to a cemented carbide substrate. Such a cutter insert may be referred to as a polycrystalline diamond compact (PDC).

PCD is an example of an ultrahard (also called superabrasive) material that includes a substantially internally grown diamond grain mass that forms a skeletal mass that defines a gap between the diamond grains. PCD materials comprise at least about 80% by volume of diamond and can be prepared by treating agglomerated masses of diamond grains at ultra-high pressures of greater than about 5 GPa and temperatures of at least about 1,200 ° C. in the presence of a sintering aid.

Suitable sintering aids for PCD may also be referred to as catalyst materials for diamond. Catalyst materials for diamond are understood to be materials that can promote the direct internal growth of diamond at temperatures and pressures where diamond is thermodynamically more stable than graphite. Some catalyst materials for diamond may promote the conversion of diamond to graphite at ambient temperatures, particularly at elevated temperatures. Examples of catalyst materials for diamond are cobalt, iron, nickel and certain alloys including any of these. PCD can be formed on a cobalt-cement tungsten carbide substrate that can provide a source of cobalt catalyst material for the PCD. The gap with the PCD may be at least partially filled by a specific material, which may be referred to as a binder or filler material. In particular, the gap may be filled in whole or in part by the catalytic material for diamond.

Components comprising PCDs are used in a wide range of tools for cutting, machining, drilling, or dismantling hard or abrasive materials such as rock, metal, ceramic, composite and wood-containing materials. For example, PCD bodies are commonly used as cutter inserts on drill bits used for mining in the oil and gas drilling industry. PCD bodies are also used to machine and mill metal-containing bodies that can be used in the automotive industry. In many of these products, the temperature of the PCD material rises as it combines with rock formation, workpieces or high energy bodies.

PCD is very hard and abrasive resistant, which is why it is a preferred tool material in some critical machining and drilling conditions that require high productivity. A disadvantage of certain catalyst materials containing PCD for diamond as filler material is that they may be relatively poor in thermal stability above about 400 ° C. This catalytic material may promote decomposition of the PCD at high temperatures that may be experienced in the manufacture and use of PCD compacts, especially at temperatures above about 750 ° C.

US Patent Application Publication No. 2007/0079994 discloses a thermally stable diamond-bonded compact comprising a diamond-bonded body comprising a thermally stable region extending below the diamond-bonded body surface. This thermally stable region has a material microstructure comprising a matrix first phase of diamond crystals bonded together and a second phase sandwiched within the matrix first phase. The second phase comprises one or more reaction products formed between one or more infiltrant materials and diamond crystals under high pressure / high temperature (HPHT) conditions. Infiltration materials or alternative materials may be used in compounds containing conventional solvent-catalyst materials (transition metals) that react with other materials to inactivate them, such as Si, Cu, Sn, Zn, Ag, Au, Ti, Cd, Al And may include one or more of Mg, Ga, and Ge.

US Patent Application Publication No. 2008/0230280 discloses a PCD structure comprising a first region located away from the surface and comprising a substitute material. The alternative material may be a non-crystallized material disposed in the gap region between the diamond crystals in the first region. The non-crystallized material has a melting point of less than about 1,200 ° C. and may be selected from elemental alloys containing low melting point metallic materials and / or periodic table IB elements, such as copper. Alternative materials are negligible or exhibit no solubility for carbon.

There is a need to provide a polycrystalline diamond (PCD) member with improved thermal stability.

It is an object of the present invention to provide a PCD member having improved thermal stability.

A first aspect of the invention is a polycrystalline diamond (PCD) member having inner diamond surfaces, the inner diamond surfaces defining a gap therebetween, the PCD member comprising a working surface; A low melting point region adjacent the working surface, the gaps being at least partially filled with a low melting point metallic material having a melting point of less than about 1,300 ° C. at atmospheric pressure, or less than about 1,200 ° C. at atmospheric pressure; And an intermediate region extending from about 5 to about 600 microns away from the boundary defined by the low melting point region, wherein the gap in the intermediate region is at least partially filled with a catalyst material for diamond. .

In one embodiment, the PCD member bonds with the substrate at the interface and the middle region of the PCD member extends from the defined boundary between the low melting point region and the interface. In some embodiments, the intermediate region extends from the boundary at a distance of about 400 microns or less, about 200 microns or less, about 100 microns or less, about 50 microns or less, about 10 microns or less, or even about 5 microns or less. In some embodiments, the intermediate region extends from the boundary at a distance of at least about 5 microns, at least about 10 microns, at least about 50 microns, at least about 100 microns, or even at least about 200 microns.

In one embodiment of the invention, the gap in the middle region is at least 50% filled by a sintering aid or catalyst material for diamond, for example cobalt.

In some embodiments, the low melting point region extends from the working surface to a depth in the PCD member, the depth of which is no greater than about 1,000 microns, no greater than about 500 microns, or no greater than about 100 microns. In some embodiments, the low melting point region extends from the working surface to a depth in the PCD member, the depth of which is at least about 5 microns, at least about 10 microns, at least about 50 microns, at least about 100 microns, or even at least about 200 microns. .

In one embodiment, the low melting point region is in the form of strata or layers. In some embodiments, the low melting point region is in the form of a layer or strata extending from a working surface to a depth of at least about 40 microns, at least about 100 microns, or even at least about 200 microns.

In one embodiment of the invention, the gaps in the low melting region are filled by at least about 50%, at least about 70%, at least about 80%, or at least about 90% by the low melting point metallic material.

In one embodiment of the invention, the low melting metallic material has a melting point lower than 1,100 ° C. at atmospheric pressure.

In one embodiment of the present invention, the low melting metallic material has a melting point above about 600 ° C., or above about 700 ° C. at atmospheric pressure.

Embodiments of the present invention have the advantage that the low melting point metallic material does not substantially melt when the PCD member is fused onto the tool carrier at a temperature of several hundred degrees Celsius.

In one embodiment of the present invention, the low melting metallic material cannot react to such an extent that it forms a stable carbide at less than about 1,000 ° C. at atmospheric pressure.

Embodiments of the present invention have the advantage that the low melting point metallic material does not react with diamond to form carbides. The formation of carbide grains delays the rate of penetration of low melting point metallic materials in manufacturing and can cause undesirable stresses in the gaps due to volume changes caused by the formation of new phases and compounds. Carbide, which is formed as a reaction product by the reaction between the low melting point metallic material of the PCD and diamond, will require the sacrifice of some surrounding diamond to react, which can threaten the integrity of the microstructure.

In some embodiments of the invention, the low melting metallic material is Ag, Mg, Cu or Pb in elemental form, or an alloy comprising any of these elements, and in some embodiments the low melting metallic material is Ag or Cu or an alloy containing any of these elements. In one embodiment, the low melting metallic material is characterized by being substantially resistant to oxidation.

Embodiments of the present invention provide the advantage of improved thermal stability without substantially sacrificing strength.

In one embodiment of the invention, the PCD member binds at the interface with a cement carbide substrate, such as a cobalt-cement tungsten carbide substrate, and in one embodiment, the PCD member has a coefficient of thermal expansion between the PCD and the hard-metal intermediate. It binds with the hard-metal substrate through the bonding layer having. In one embodiment, the bonding layer comprises diamond grains and metal carbide, wherein the diamond grains do not substantially bond with each other. In one embodiment, the PCD member comprises an intermediate region spaced from the working surface, wherein the gaps are filled at least 50% by the catalytic material for diamond, the intermediate region is adjacent to the interface, and the low melting point region is from the interface. Are spaced apart.

A second aspect of the invention provides an insert for a tool, wherein the insert comprises an embodiment of a PCD member according to the invention.

A third aspect of the invention provides a tool comprising an embodiment of an insert according to the invention.

In some embodiments, the tool is suitable for machining, drilling, drilling, cutting, or otherwise forming or decomposing hard or abrasive workpieces or other bodies, such as rock, concrete, asphalt, metal or hard composite materials. . In some embodiments, the tool is a drill bit for use in underground drilling, rock drilling or rock decomposition that can be used in oil and gas drilling and mining, and in one embodiment, the tool is used for underground drilling and Rotating drag bit for use in rock drilling.

A fourth aspect of the invention is a method of making a PCD member, comprising: providing a PCD body comprising a sintering aid in the gaps of the PCD body; Removing at least a portion of the sintering aid from a portion of the polycrystalline diamond member to form a porous region adjacent the work surface; And invading or infiltrating at least a portion of the porous region with a low melting point metallic material having a melting point of less than about 1,300 ° C. at atmospheric pressure, or less than about 1,200 ° C. at atmospheric pressure.

In one embodiment, substantially all of the sintering aid is removed from the PCD member.

One embodiment of the method of the present invention includes preventing or avoiding filling of voids in the portion of the porous region with low melting point metallic material.

One embodiment of the method of the invention comprises infiltrating a catalyst material for diamond, for example a material comprising cobalt, into a portion of the porous region not filled by a low melting point metallic material.

In one embodiment of the present invention, a temperature control cycle is employed in which a sufficient or specific amount of low melting point metallic material is introduced into the porous region so as to be penetrated by the material comprising the catalytic material for diamond.

Non-limiting embodiments are now described with reference to the drawings.
1 shows a schematic longitudinal cross sectional view of an embodiment of a PCD member.
2 shows a schematic enlarged cross-sectional view of the area of the embodiment shown in FIG. 1.
3A shows a schematic perspective view of a part used in an embodiment of a method of making a PCD compact or insert.
3B shows a schematic perspective view of an embodiment of a PCD compact or insert.
Unless indicated otherwise, like reference numerals in the drawings denote like features.

As used herein, a “working surface” of an insert or member is any portion of an insert or member that, in use, can come into contact with the workpiece or body being worked on. It is also understood that any work surface portion is a work surface.

As used herein, the term "low melting point metallic material" means a metal in the form of an element or alloy with metallic properties including high electrical conductivity, thermal conductivity and fracture toughness. The term excludes metal compounds such as metal carbides, oxides, nitrides, carbo-nitrides, and other ceramics, or low melting point intermetallic materials that do not have metal properties.

As used herein, the catalyst material for diamond is a material that can promote the accompanying precipitation, growth and / or sintering of grains of diamond under pressure and temperature conditions where diamond is thermodynamically more stable than graphite. Examples of catalytic materials for diamond are iron, nickel, cobalt, manganese, and certain alloys including any of these elements. Some catalyst materials for diamond can promote the conversion of diamond to graphite at atmospheric pressure, especially at elevated temperatures.

1 and 2, an embodiment of PCD insert 200 includes an embodiment of PCD member 100 connected with cement carbide substrate 220 at interface 116. Embodiments of the PCD member 100 have an inner diamond surface 102, which defines a gap 104 therebetween. The PCD member 100 further includes a work surface 114 and a low melting point region 111 adjacent to the work surface 114, wherein the gap 104 is less than about 1,300 ° C. at atmospheric pressure, or 1,200 ° C. at atmospheric pressure. At least partially filled by a low melting metallic material with a melting point of less than. The intermediate region 112 extends about 5 to about 600 microns away from the boundary 116, and the gap 104 in the intermediate region 112 is at least partially filled by the catalytic material for diamond. In this embodiment, the boundary is an interface (all denoted by reference numeral 116).

It is contemplated that those skilled in the art will be able to produce PCD inserts of various shapes and sizes depending on the type of product. The insert is particularly advantageous when it is used in articles which are capable of high temperature processing and therefore high thermal stability is important. Particularly preferred products are inserts for rotary drill bits used for rock drilling and underground drilling in the oil and gas industry.

Referring to FIG. 3A, an embodiment of a method of making a PCD member includes providing a PCD insert 300 manufactured using the ultra-high pressure and high temperature (HPHT) methods well known in the art. Insert 300 includes a PCD member 310 integrally coupled with cement carbide hard-metal substrate 320. The microgap (not shown) of the PCD member 310 is substantially filled by the cobalt catalyst material. At least a portion of the PCD member 310 is detached from the insert 300 to produce the PCD body 311. One way to detach the PCD member 310 is to crush the substrate 320. The PCD body 311 is processed to remove the catalyst material from the gap to create a porous and thermally stable PCD member 312. The porous PCD member 312 then contacts one side with the second cement carbide substrate 340 and the other side with a source 330 of low melting point metallic material. Source 330 may be in the form of a thin foil or disc, or powder. The substrate 340 may include tungsten carbide grains and cobalt metal binders, where the metal binders may act as catalyst materials to promote growth and sintering of diamond grains.

The porous PCD member 312 thus “sandwiched” between the substrate 340 and the foil or disk 330 may have an excess of about 5 at a temperature high enough to melt the low melting point metallic material and the cobalt metal binder of the substrate 340. It is processed at the very high pressure of GPa to allow some of it to penetrate into the porous PCD member 312. The temperature cycle can be controlled in such a way that a sufficient or specific amount of low melting point metallic material is introduced into porous PCD member 312 before the cobalt metal binder material melts and penetrates into porous PCD member 312. After this treatment, the resulting insert is removed and processed to final dimensions and tolerances to produce an embodiment of the finished PCD insert 200 shown in FIG. 3B that includes the PCD member 100 associated with the cement carbide substrate 220. do.

In one embodiment, the PCD body has a thickness of at least about 1.5 mm, or at least about 1.8 mm, as a thickness between a pair of opposing surfaces, wherein one of the surface pairs is in contact with a source of low melting point metallic material, and among the surface pairs The other is in contact with a source of catalyst material for diamond.

One embodiment of the method of the present invention comprises heating a source of low melting metal material to a temperature between the melting point of the low melting metal material and the melting point of the catalytic material, and the infiltration or penetration of the low melting metal material completed. Maintaining within said range for a time sufficient to become. In one embodiment, this temperature is then increased to a temperature above the melting point of the catalyst material for the time that the introduction of the catalyst material is complete.

One embodiment of the method comprises contacting one surface of the porous PCD body with a silver source, contacting another surface of the PCD body with a cobalt source to form an assembly, applying the assembly to a pressure of at least about 5.5 GPa Heating the assembly to a temperature in the range above the melting point of silver at the pressure and below the melting point of cobalt at the pressure, and maintaining the temperature in the range for at least about 2 minutes or at least about 3 minutes. And then increasing this temperature above the melting point of cobalt at said pressure.

One embodiment of the method comprises contacting one surface of the porous PCD body with a copper source, contacting another surface of the PCD body with a cobalt source to form an assembly, applying the assembly to a pressure of at least about 5.5 GPa Heating the assembly to a temperature in the range above the melting point of copper at the pressure and below the melting point of cobalt at the pressure, and maintaining the temperature in the range for a time of at least about 1 minute or at least about 2 minutes. And then increasing this temperature above the melting point of cobalt at said pressure.

In some embodiments, the time is about 15 minutes or less, or even about 10 minutes or less.

Sintered PCD bodies can be produced in ultra high pressure furnaces by sintering diamond grains together in the presence of a catalyst material for diamond at a pressure of at least about 5.5 GPa and at a temperature of at least about 1,300 ° C. The catalytic material may comprise diamond catalyst materials of the conventional transition metal type, such as cobalt, iron or nickel, or certain alloys thereof. The sintered PCD body may be thermally stabilized in whole or at least a portion thereof, for example, by removing most of the binder catalyst material from the PCD body or the desired area using an acid leaching process or other similar processes known in the art. Can be.

The catalytic material present in the PCD body 311 can be any of a variety of methods known in the art, such as electrolytic etching, evaporation techniques, acid leaching (eg, fluorination), as disclosed in WO 2007/042920. By immersion into a liquid containing hydrochloric acid, nitric acid or mixtures thereof, or by chlorine gas, or by other methods (e.g., disclosed in South African Patent No. 2006/00378).

In one embodiment of the method, a PCD insert similar to PCD insert 300 in FIG. 3A is provided. The region adjacent the working surface of the PCD member is substantially deficient in catalytic material by methods known in the art, such that the region is porous. Low melting point metallic material is introduced into the pores of the porous region. The parameters of the introduction method can be controlled to maintain porosity in the porous region portion. The catalytic material then penetrates into the remaining pores of the masked or passivated region. This brings the source of catalytic material into contact with the working surface of the PCD member and assembles the PCD insert and this source into a capsule of the type used for the HPHT sintering of the PCD, which assembles the catalyst material and melts the diamond over the graphite. It can be achieved by applying to a thermally more stable temperature and ultrahigh pressure. In some embodiments, the pressure is at least about 5.5 GPa, at least about 6 GPa, or at least about 6.5 GPa. In one embodiment, the pressure is about 6.8 GPa.

The low melting point metallic material according to the invention is substantially inert to diamond and does not substantially promote dissolution or decomposition of the diamond at ambient pressure. It can act as a thermally conductive filler in the PCD member. While not wishing to be bound by any particular hypothesis, low melting point metallic materials are not considered to degrade diamond at high temperatures that may be experienced during use, i. At temperatures where the low melting point metallic material is in the solid phase, its pressure in the gaps can improve the strength of the PCD. In addition, the high thermal conductivity of the low melting metallic material can further improve the thermal stability of the polycrystalline diamond member compared to the leached PCD. At a temperature at or near the low melting point metallic material, it is possible to prevent the stress in the PCD from increasing due to leaching from the gaps as the low melting point metallic material thermally expands or melts. Solid metals near their melting point generally have a greatly reduced yield strength, which can reduce the increase in micro-stress that can result from mismatches in the coefficient of thermal expansion. Melting or softening of such metals may have the added advantage of facilitating the action of the polycrystalline diamond member at high temperatures. The low melting point of the low melting metallic material means that a relatively low temperature is required to penetrate it into the polycrystalline diamond member. In some embodiments of the method of the present invention, the rate and extent of penetration can be easily controlled by controlling the viscosity by controlling the temperature without the need to use very high temperatures.

Example

The present invention is described below by way of illustration only with reference to the following non-limiting examples.

Example 1

PCD inserts with a diameter of about 16 mm used for rotary drag bits for oil and gas drilling were used as starting parts. This insert consisted of a PCD layer substantially cylindrical in shape and integrally bonded with a Co-cement WC hard-metal substrate. The PCD layer is about 2.3 mm thick and the diamond grain size distribution is multi-modal, comprising sintered diamond grains having an average grain size of less than about 20 microns, and the gaps between the diamond grains are PCD sintered. It is filled with Co, the catalytic metal supplied from the hard-metal substrate during the step. Virtually all hard-metal substrates were machined from the PCD layer to provide PCD discs. This was then infiltrated with a mixture of hydrofluoric acid and nitric acid for several days to remove substantially all Co from the PCD disk, resulting in a porous desorbed PCD disk. The PCD disc was heat treated under vacuum to remove (ie, degas) any residual organic impurities that may be present.

The porous PCD discs were then re-penetrated with cobalt from one side and copper from the other side and simultaneously re-bonded with the second Co-cement WC substrate. This re-penetration step was performed at an ultrahigh pressure of greater than about 5 GPa, in which the diamond was thermodynamically stable, and at a temperature of about 1,400 ° C. where Co was melted at that ultrahigh pressure. To carry out this step, a pre-form assembly was prepared, which included a porous PCD disc located on the flat surface of the cylindrical substrate and a thin copper film located on the porous PCD disc. The copper film was less than 0.5 mm thick and was ultrasonically cleaned in an acetone bath.

An assembly comprising a PCD disc so "sandwiched" between the copper foil and the substrate was placed in a heat resistant metal jacket, as is well known in the art, and then placed in a ceramic support and then sealed in another metal casing. This preform assembly was assembled into an ultrahigh pressure furnace capsule and subjected to ultrahigh pressure and temperature. Once the target pressure was reached, the temperature was increased from ambient temperature to maximum level over a period of time.

After the re-infiltration step, the insert was removed from the ultrahigh pressure device and the casing and jacket were removed. The insert was then divided into two parts along the axial plane to create two cross sections. One of these surfaces was polished and analyzed by scanning electron microscopy (SEM), revealing that the PCD is well bonded to the substrate and substantially all of the gaps within the PCD are filled by copper, cobalt or a combination thereof, and cobalt. lost. Copper penetrates to a depth of about 1.7 mm from the flat working surface and the area at about 1.3 mm from the flat working surface is substantially free of cobalt. PCD gaps within about 0.2 mm from the substrate were mainly filled with cobalt, but some copper also appeared.

A second test insert was prepared as above and subjected to a wet test that involves machining graphite blocks mounted on a vertical turret milling device using appropriately prepared inserts as the skilled person will recognize. The PCD layer showed good wear resistance and thermal stability.

Example 2

Re-penetrated inserts were prepared using the same process as in Example 1 except that silver foil was used instead of copper foil. This insert was also analyzed and tested as in Example 1.

Silver penetrated deeper than copper to about 2.2 mm deep into the PCD from a flat working surface. This is thought to be due to the lower melting point of the silver, consequently melting at an earlier stage than copper, and therefore the time required for the porous PCD to penetrate before the cobalt melts and begins to penetrate from the opposite direction.

Example 3

Porous PCD discs can be made using the process described in Example 2 and silver can be introduced into the voids before the ultrahigh pressure treatment. This can be accomplished by placing the porous PCD in a graphite vessel and placing the ultrasonically cleaned silver film in an acetone bath on top of it. The vessel can then be placed in a furnace and the contents heated to above the melting point of silver, ie, at about 1,000 ° C. under vacuum, so that the silver foil melts and penetrates the PCD disc.

Example 4

Porous PCD discs can be prepared using the process described in Example 2 and silver can be introduced into the voids prior to the ultrahigh pressure treatment by depositing a very thin film of silver over the surface of the PCD disc by sputtering and melting the silver. have. Only 10% of the pores are filled with silver, so silver penetrates to a depth of about 10% of the thickness of the PCD, that is to a depth of about 230 microns from a flat surface, and the remaining pores provide enough silver to be substantially empty. The mass of deposited silver can be calculated. This mass may be about 12.5 mg. The film thickness should be as uniform as possible over the PCD surface.

The silver-coated PCD was then placed in a graphite vessel, with the coated surface spaced apart from the base of the graphite vessel (ie at the top surface) and the vessel placed in the furnace. The vessel and its contents may be heated under vacuum to above the melting point of silver, ie about 1,000 ° C., to allow the silver coating to melt and penetrate the PCD disc.

Example 5

Independent, fully leached PCD discs were prepared following a process similar to that described in Example 1. A diamond powder having a size distribution capable of dissolving into two or more distinct peaks is placed against a cobalt cement tungsten carbide substrate, and the assembly is encapsulated in a refractory metal jacket and treated at a pressure of at least about 5.5 GPa and at a temperature of at least about 1,500 ° C. The diamond powder was then sintered into a PCD layer bonded to the substrate. After sintering, the carbide base is wrapped and, as is well known in the art, substantially all cobalt is removed from the gaps of the PCD by leaching in acid liquid to form a porous PCD body, generally in the form of a disk. The PCD disc was then separated from the substrate.

The copper disk was positioned against one end of the porous PCD body and the cobalt cement tungsten carbide substrate was positioned against the opposite end of the PCD body and the assembly was encapsulated in a refractory metal jacket. The porous PCD body was thus sandwiched between the substrate and the copper disk. The copper disk had a thickness of about 0.25 mm and the diameter was substantially the same as the diameter of the PCD body. The mass of the copper disk was about 420 mg, which is less than about 10% of the PCD body volume, which is believed to exceed the volume level needed to fill the entire void created during the leaching process.

This assembly was further cased in a manner known in the art for HPHT sintering and subjected to a second high pressure, high temperature cycle at a temperature of about 1,410 ° C. and a pressure of about 5.2 GPa. PCD inserts comprising a PCD layer containing copper and cobalt and bonded with the substrate were recovered and machined to final specifications to form a PCD cutter insert.

This PCD cutter insert was subjected to a milling test considered to be a very thermally aggressive test involving the high speed rotational cutting of graphite workpieces. The results show that the thermal stability is much higher than that of the PCD cutter insert control group, which did not undergo the re-infiltration process of copper.

Example 6

Another material was prepared using the method disclosed in Example 5 except that the copper disk was replaced with 520 mg of silver powder. Once again, a mass corresponding to about 10% by volume of the fully leached disc was selected. The conditions selected for the second high pressure and high temperature cycle were the same as those used in Example 5. Performance results from this material indicated that the thermal stability was improved over that of the non-repenetrated PCD.

Claims (17)

A polycrystalline diamond (PCD) member having internal diamond surfaces,
The inner diamond surfaces define the gaps between them,
The PCD member is
Working surface;
A low melting point region adjacent the working surface and at least partially filled by the gaps with a low melting point metallic material having a melting point of less than about 1,300 ° C. at atmospheric pressure; And
An intermediate region extending about 5 to about 600 microns from the boundary defined by the low melting point region
Including,
Wherein the gaps in the middle region are at least partially filled by a catalyst material for diamond. The method of claim 1,
And wherein said intermediate region extends at a distance of about 400 microns or less from said boundary. The method according to claim 1 or 2,
And wherein said intermediate region extends a distance of at least about 5 microns from said boundary. The method according to any one of claims 1 to 3,
Wherein the gaps in the intermediate region are at least 50% filled with a sintering aid or catalyst material for diamond. The method according to any one of claims 1 to 4,
And the low melting point region extends from the working surface into the PCD member to a depth of about 1,000 microns or less. 6. The method according to any one of claims 1 to 5,
And the low melting region extends from the working surface into the PCD member to a depth of at least about 5 microns. The method according to any one of claims 1 to 6,
Wherein said low melting point region is in the form of a stratum or layer. The method according to any one of claims 1 to 7,
Wherein the gaps in the low melting region are at least 50% filled by the low melting metallic material. The method according to any one of claims 1 to 8,
And wherein said low melting metallic material has a melting point lower than 1,100 [deg.] C. at atmospheric pressure. The method according to any one of claims 1 to 9,
And wherein said low melting point metallic material has a melting point higher than 600 [deg.] C. at atmospheric pressure. The method according to any one of claims 1 to 10,
Wherein the low melting point metallic material is incapable of reacting to form a stable carbide at less than about 1,000 ° C. at atmospheric pressure. The method according to any one of claims 1 to 11,
And wherein said low melting metallic material is an elemental form of Ag, Mg, Cu or Pb, or an alloy comprising any of these elements. The method according to any one of claims 1 to 12,
The polycrystalline diamond member, wherein the low melting point metallic material is Ag or Cu in elemental form, or an alloy comprising any of these elements. An insert for a tool comprising the polycrystalline diamond member according to claim 1. A tool comprising the insert according to claim 14. As a method for producing a polycrystalline diamond (PCD) member,
Providing a PCD body comprising a sintering aid in the gaps of the PCD body;
Removing at least a portion of the sintering aid from a portion of the PCD member to form a porous region adjacent the working surface; And
Invading or infiltrating at least a portion of the porous region with a low melting point metallic material having a low melting point of less than about 1,300 ° C. at atmospheric pressure
Including, the method. 17. The method of claim 16,
Substantially all of the sintering aid is removed from the polycrystalline diamond member.

Images