ELEMENCT ONTAININTGH ERMALLSYT ABLEP OLYCRYSTALLDINIAE MOND
MATERIAALN D METHODASN D ASSEMBLIEFSO RF ORMATIOTNH EREOF
TECHNICAL FIELD
The current disclosure relates to a super abrasive element containing a superabrasive
body, such as a thermally stable polycrystalline diamond (TSP) body,
bonded to a base via an infiltrant material. In more specific embodiments, the TSP
5 body may substantially free of infiltrant material, with only a small amount present
near the TSP body surface in contact with the base. In some embodiments, the
infiltrant material may also permeate the base, where if may function as a binder. The
current disclosure also relates to methods of forming a super abrasive element
containing a TSP body bonded to a base using an infiltrant material. In particular
10 embodiments, the method may include forming a super abrasive element by forming
the base in a mold also containing the TSP in the presence of the infiltrant material.
BACKGROUND
Components of various industrial devices are often subjected to extreme
15 conditions, such as high impact contact with abrasive surfaces. For example, such
extreme conditions are commonly encountered during subterranean drilling for oil
extraction or mining purposes. Diamond, with its unsurpassed wear resistance, is the
most effective material for earth drilling and similar activities that subject components
to extreme conditions. Diamond is exceptionally hard, conducts heat away from the
20 point of contact with the abrasive surface, and may provide other benefits in such
conditions.
Diamond in its polycrystalline form has added toughness as compared to
single crystal diamond due to the random distribution of the diamond crystals, which
avoids the particular planes of cleavage found in single diamond crystals. Therefore,
25 polycrystalline diamond is frequently the preferred form of diamond in many drilling
applications or other extreme conditions. Device elements have a longer usable life in
these conditions if their surface layer is made of diamond, typically in the form of a
polycrystalline diamond (PCD) compact, or another super abrasive material.
Elements for use in harsh conditions may contain a PCD layer bonded to a
substrate. The manufacturing process for a traditional PCD is very exacting and
expensive. The process is referred to as "growing" polycrystalline diamond directly
onto a carbide substrate to form a polycrystalline diamond composite compact. The
5 process involves placing a cemented carbide piece and diamond grains mixed with a
catalyst binder into a container of a press and subjecting it to a press cycle using
ultrahigh pressure and temperature conditions. The ultrahigh temperature and
pressure are required for the small diamond grains to form into an integral
polycrystalline diamond body. The resulting polycrystalline diamond body is also
10 intimately bonded to the carbide piece, resulting in a composite compact in the form
of a layer of polycrystalline diamond intimately bonded to a carbide substrate.
A problem with PCD arises from the use of cobalt or other metal
catalystlbinder systems to facilitate polycrystalline diamond growth. After crystalline
growth is complete, the catalystlbinder remains within pores of the polycrystalline
15 diamond body. Because cobalt or other metal catalystlbinders have a higher
coefficient of thermal expansion than diamond, when the composite compact is
heated, e.g., during the brazing process by which the carbide portion is attached to
another material, or during actual use, the metal catalystlbinder expands at a higher
rate than the diamond. As a result, when the PCD is subjected to temperatures above
20 a critical level, the expanding catalystlbinder causes fractures throughout the
polycrystalline diamond structure. These fractures weaken the PCD and can
ultimately lead to damage to or failure.
As a result of these or other effects, it common to remove the catalyst from
part of the PCD layer, particularly the parts near the working surface. The most
25 common process for catalyst removal uses a strong acid bath, although other
processes that employ alternative acids or electrolytic and liquid metal techniques also
exist. In general, removal of the catalyst from the PCD layer using an acid-based
method is referred to as leaching. Acid-based leaching typically occurs first at the
outer surface of the PCD layer and proceeds inward. Thus, traditional elements
30 containing a leached PCD layer are often characterized as being leached to a certain
depth from their surface. PCD, including regions of the PCD layer, from which a
substantial portion of the catalyst has been leached is referred to as thermally stable
PCD (TSP). Examples of current leaching methods are provided in U.S. 4,224,380;
U.S. 7,712,553; U.S. 6,544,308; U.S. 20060060392 and related patents or
applications.
Acid-leaching leaching must also be controlled to avoid contact between
5 substrate or the interface between the substrate and the diamond layer and the acids
used for leaching. Acids sufficient to leach polycrystalline diamond severely degrade
the much less resistant substrate. Damage to the substrate undermines the physical
integrity of the PCD element and may cause it to crack, fall apart, or suffer other
physical failure while in use, which may also cause other damage.
10 The need to carefully control leaching of elements containing a PCD layer
significantly adds to the complications, time, and expense of PCD manufacturing.
Additionally, leaching is typically performed on batches of PCD elements. Testing to
ensure proper leaching is destructive and must be performed on a representative
element from each batch. This requirement for destructive testing further adds to
15 PCD element manufacturing costs.
Attempts have been made to avoid the problems of leaching a fully formed
element by separately leaching a PCD layer, then attaching it to a substrate.
However, these attempts have failed to produce usable elements. In particular, the
methods of attaching the PCD layer to the substrate have failed during actual use,
20 allowing the PCD layer to slip or detach. In particular, elements produced using
brazing methods, such as those described in U.S. 4,850,523; U.S. 7,487,849, and
related patents or applications, or mechanical locking methods such as those described
in U.S. 7,533,740 or U.S. 4,629,373 and related patents or applications are prone to
failure.
25 Other methods of bonding a PCD layer to a pre-formed substrate are described
in U.S. 7,845,438, but require melting of a material already present in the substrate
and infiltration of the PCD layer by the material.
In still other methods, leached PCD layers have been attached directly to the
gage region of a bit by infiltrating the entire bit and at least a portion of the PCD layer
30 with a binder material. Although these methods are suitable to attaching PCD to a
gage region, where it need not be removed during the lifetime of the bit, they are not
suitable for placing PCD layers in the cutting regions of a bit, where replacement or
rotation of the PCD is desirable for providing normal bit life.
Using still other methods, PCD elements, often referred to as geosets, have
been incorporated into the exterior portions of drill bits. Geosets are typically coated
5 with a metal, such as nickel (Ni). Geoset coatings may provide various benefits, such
as protection of the diamond at higher temperature and improved bonding to the drill
bit matrix.
Accordingly, a need exists for an element, including a rotatable or replaceable
element, having a leached PCD layer, such as a TSP body, attached to a base or
10 substrate sufficiently well to allow use of the element in high temperature conditions
such as those encountered by cutting elements of an earth-boring drill bit.
SUMMARY
The disclosure, according to one embodiment, provides a super abrasive
element containing a substantially catalyst-free thermally stable polycrystalline
15 diamond (TSP) body having pores and a contact surface, a base adjacent the contact
surface of the TSP body; and an infiltrant material infiltrated in the base and in the
pores of the TSP body at the contact surface.
According to another embodiment, the disclosure provides an earth-boring
drill bit containing such a super abrasive element in the form of a cutter.
20 According to still another embodiment, the disclosure provides an assembly
for forming a super abrasive element including a mold having a bottom, a thermally
stable polycrystalline diamond (TSP) body having a contact surface and located in the
bottom of the mold, a matrix powder disposed adjacent the contact surface and above
the TSP body in the mold, and an infiltrant material disposed above the matrix
25 powder in the mold.
According to a further embodiment, the disclosure provides an assembly for
forming a super abrasive element including a mold, a thermally stable polycrystalline
diamond (TSP) body having a contact surface and located in the mold, a matrix
powder disposed adjacent the contact surface in the mold, and an infiltrant or binder
30 material disposed in the matrix powder in the mold.
The disclosure additionally provides a method of forming a super abrasive by
assembling an assembly including a mold having a bottom, a thermally stable
polycrystalline diamond (TSP) body having pores and a contact surface and located in
the bottom of the mold, a matrix powder disposed adjacent the contact surface and
above the TSP body in the mold, and an infiltrant material disposed above the matrix
powder in the mold. The method further includes heating the assembly to a
5 temperature and for a time sufficient for the infiltrant material to infiltrate the matrix
powder and pores of the TSP body, and cooling the assembly to form a super abrasive
element.
The disclosure further provides an additional method of forming a super
abrasive element including assembling an assembly including a mold, a thermally
10 stable polycrystalline diamond (TSP) body having pores and a contact surface and
located in the mold, a matrix powder disposed adjacent the contact surface in the
mold, and an infiltrant or binder material disposed in the matrix powder. The method
also includes heating the assembly to a temperature and pressure and for a time
sufficient for the infiltrant or binder material to infiltrate the matrix powder to form a
15 base attached to the TSP body.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present embodiments and advantages
thereof may be acquired by referring to the following description taken in conjunction
with the accompanying drawings, which depict embodiments of the present
20 disclosure, and in which like numbers refer to similar components, and in which:
FIGURE 1 is a cross-sectional side view of an infiltration method assembly
for forming a super abrasive element containing a TSP body bonded to a base via an
infiltrant material;
FIGURE 2 is a magnified cross-sectional view of a super abrasive element;
25 FIGURE 3 is a cross-sectional side view of a hot press method assembly for
forming a super abrasive element containing a TSP body bonded to a base via an
infiltrant material;
FIGURE 4 is a side view of a TSP body for use in one embodiment of the
present disclosure;
30 FIGURES 5A and 5B are top and side views of super abrasive elements;
FIGURE 6 is a side view of a carbide casting reinforcement for use in one
embodiment of the present disclosure;
FIGURE 7 is a side view of a super abrasive element having a dovetail lock;
FIGURE 8 is a side view of a super abrasive element having a lateral lock; and
FIGURE 9 is a side view of a super abrasive element having a combined
dovetail and lateral lock.
5 DETAILED DESCRIPTION
The current disclosure relates to a super abrasive element containing a super
abrasive body, such as a thermally stable polycrystalline diamond (TSP) body bound
to a base via an infiltrant material. The disclosure also relates to tools containing
such super abrasive elements as well as methods of making such super abrasive
10 elements. In general, during methods of making super abrasive elements, the super
abrasive properties of the super abrasive body, such as a TSP body, may remain
substantially unchanged or undeteriorated.
Although in the example embodiments described herein, superabrasive
elements are in a generally cylindrical shape with a flat surface, they may be formed
15 in any shape suitable for their ultimate use, such as, in some embodiments, a conical
shape, a variation of a cylindrical shape, or even with angles. Additionally, the
surface of the superabrasive elements in some embodiments may be concave, convex,
or irregular.
An assembly 10, as shown in FIGURE 1, may be provided for use in forming
20 a super abrasive element via an infiltration method. Assembly 10 may include mold
20 intended to contain the components of the super abrasive element while it is being
formed. TSP body 30 may be disposed within mold 20. TSP body 30 may
substantially lack catalyst used in forming the body. For instance, at least 85% of the
catalyst may be removed from the body. Matrix powder 40 may also be disposed
25 within mold 20 on top of TSP body 30. Finally, infiltrant material 50 may be
disposed within mold 20 on top of matrix powder 40.
To form a super abrasive element, assembly 10 may be subjected to a
formation process during which matrix powder 40 is infiltrated by infiltrant material
50, which functions as a binder, and eventually forms a base. Infiltrant material 50
30 wets the surface of TSP body 30 in contact with matrix powder 40 and fills pores in
TSP body 30 at the surface, attaching TSP body 30 to the base. FIGURE 2 shows a
magnified image of a cross-section of a super abrasive element 60 that may be
formed. Super abrasive element 60 includes the TSP body 30 bound to a base 70 that
is formed from the matrix powder 40. In a particular embodiment, infiltrant material
50 may be dispersed within base 70 as a binder and also infiltrate pores in the contact
5 surface 100 of TSP body 30, which is in contact with base 70, to a depth of D to form
infiltrant material-containing region 80. The remainder of TSP body 30 may
substantially lack binder and may form infiltrant-free region 90. Pores may be
engineered to allow the formation of a micromechanical bond between the base and
the TSP rather than merely a metallurgical bond.
10 According to another embodiment (not shown) infiltrant material 50 may be
intermixed with matrix powder 40 prior to the formation process. In such an
embodiment, infiltrant material nevertheless infiltrates matrix powder 40 and wets the
surface of TSP body 30, also filling in pores on that surface, to allow attachment of
base 70 formed from matrix powder 40 to TSP body 30.
15 According to a further embodiment shown in FIGURE 3, a superabrasive
element 60 of the type depicted in FIGURE 2 may be formed using an assembly 10a
and a hot press method. Assembly 10a may include mold 20a intended to contain the
components of the super abrasive element while it is being formed. TSP body 30 may
be disposed within mold 20a. Matrix powder 40a may be disposed within mold 20a
20 as well. Typically when using a hot press method, an infiltrant material is intermixed
with the matrix powder prior to hot pressing. Accordingly, matrix powder 40a may
additionally contain a binder material intermixed therein. The binder material may be
an infiltrant material, or it may be a material not able to infiltrate TSP body 30. In
instances where the binder material cannot infiltrate TSP body 30, or cannot do so
25 sufficiently to attach it to base 70 after formation of the super abrasive element, TSP
body 30 may be attached to base 70 primarily by mechanical forces resulting from the
use of a hot press methodology. In other hot press embodiments, a disc of infiltrant
material 50 may be placed on the matrix powder 40 and used to infiltrate the matrix
powder, for instance under lower pressure.
30 In alternative embodiments, other infiltration methods, such as hot isostatic
pressing, may be used to infiltrate the matrix powder with infiltrant material.
Mold 20 used in assembly 10 may be made of any material suitable to
withstand the formation process and allow removal of the super abrasive element
formed. According to a particular embodiment, mold 20 may contain a ceramic
material. Although mold 20 is shown with a flat bottom, in certain embodiments (not
5 shown) it may be shaped to allow infiltrant material 50 to flow around the sides of
TSP body 30, assisting in mechanical attachment of TSP body 30 to base 70. Mold
20a may be any mold suitable to withstand a hot press cycle.
TSP body 30 may be in any shape suitable for use in super abrasive element
60. In some embodiments, it may be in the form of a disk, as shown in FIGURE 4.
10 TSP body 30 may have a substantially planar contact surface (not shown). However,
as shown in FIGURE 4, TSP body 30 may have features to mechanically enhance its
attachment to base 70 in the super abrasive element 60. In particular, TSP body 30
may have a non-planar contact surface 100 like that shown in FIGURE 4. The nonplanar
contact surface 100 may contain non-planar features, such as grooves 1 10.
15 Grooves 1 10 may help prevent TSP body 30 from slipping from base 70 in response
to a force applied at a right angle to the grooves. The non-planar contact surface 100
may have angled regions, such as angled walls 120 of grooves 110. These angled
walls 120 may improve the mechanical connection between TSP body 30 and base 70
by interlocking the two components.
20 Additional configurations to increase the mechanical attachment of TSP body
30 to base 70 may also be used. Two examples of such configuration are shown in
FIGURES 5A and 5B. Further mechanical attachments mechanisms may include
prior mechanical TSP attachment mechanisms that proved unsuitable when used alone
may be suitable when combined with attachment via infiltrant material 50 and may
25 actually improve the overall attachments of TSP body 30 to base 70. Example
mechanisms include those found in U.S. 7,533,740 or U.S. 4,629,373, incorporated by
reference herein. Other configurations that may increase mechanical attachment of
TSP body 30 to base 70 are shown in FIGURES 7,8 and 9. Some such
configurations, such at that shown in FIGURE 9, may apply compressive forces to the
30 TSP body, particularly during use.
Specific mechanical configurations of TSP body 30 may be used when it is
attached to base 70 mechanically through a hot press formation method, rather than
via an infiltrant material.
In addition to or alternatively to mechanically enhancing the attachment of
5 TSP body 30 the base 70, features of contact surface 100 may also increase the
contact surface area in contact with matrix powder 40 before formation of super
abrasive element 60, or in contact with base 70 after formation of super abrasive
element 60. In particular, a non-planar contact surface 100 may increase the contact
surface area. A larger contact surface area may improve bonding of TSP body 30 to
10 base 70 by providing more pores adjacent the matrix powder 40 to be infiltrated by
infiltrant material 50 or otherwise by increasing the surface wet by infiltrant material
50 during the formation process.
In some embodiments, the number or volume of pores at contact surface 100
may also help improve attachment of TSP body 30 to base 70 by providing more
15 surface area for infiltrant material 50 to wet and attach to.
TSP body 30 may be any PCD leached sufficiently to be thermally stable. At
temperatures suitable to allow infiltrant material 50 to infiltrate matrix powder 40 and
to wet and infiltrate contact surface 100 or for some hot pressing techniques,
remaining catalyst in PCD material that is not sufficiently leached will cause the
20 material to graphitize to carbon, weakening it to the point where it is not suitable for
use in a super abrasive element or possibly even causing it to disintegrate. Leaching
of the TSP body may be performed prior to its placement in assembly 10 or 10a and
prior to the formation of super abrasive element 60. TSP body 30 may be formed
using standard techniques for creating a PCD layer. In particular, it may be formed
25 by combining grains of natural or synthetic diamond crystal with a catalyst and
subjecting the mixture to high temperature and pressure to form a PCD attached to or
separate from any substrate. The PCD may contain a diamond body matrix and an
interstitial matrix containing the catalyst. According to particular embodiments, the
catalyst may include a Group VIII metal, particularly cobalt (Co).
30 The PCD may then be leached by any process able to remove the catalyst from
the interstitial matrix. The leaching process may also remove the substrate, if any is
present. In some embodiment, at least a portion of the substrate may be removed
prior to leaching, for example by grinding. In particular embodiments, the PCD may
be leached using an acid. The leaching process may differ from traditional leaching
processes in that there is no need to protect any substrate or boundary regions from
leaching. For example, it may be possible to simply place the PCD or PCDIsubstrate
5 combination into an acid bath with none of the protective components typically
employed. Even the design of the acid bath may differ from traditional acid baths. In
many processes for use with the present disclosure a simple vat of acid may be used.
An alternative leaching method using a Lewis acid-based leaching agent may
also be employed. In such a method, the PCD containing catalyst may be placed in
10 the Lewis acid-based leaching agent until the desired amount of catalyst has been
removed. This method may be conducted at lower temperature and pressure than
traditional leaching methods. The Lewis acid-based leaching agent may include ferric
chloride (FeC13), cupric chloride (CuC12), and optionally hydrochloric acid (HCl), or
nitric acid (FINO3), solutions thereof, and combinations thereof. An example of such
15 a leaching method may be found in US 1311 68,733 by Ram Ladi et al., filed June 24,
201 1, and titled "CHEMICAL AGENTS FOR LEACHING POLYCRYSTALLINE
DIAMOND ELEMENTS," incorporated by reference in its entirety herein.
When catalyst is removed from the interstitial matrix, pores are left where the
catalyst used to be located. The percent leaching of a PCD may be characterized as
20 the overall percentage of catalyst that has been removed to leave behind a pore.
Although, as noted above, a gradient in the degree of leaching may be present from
the surface of the PCD inwards, the average amount of leaching for a PCD may
nevertheless be determined. According to specific embodiments of the current
disclosure TSP body 30 may include a PCD which is substantially free of catalyst.
25 More specifically, the TSP body may include a PCD from which at least 85%, at least
90%, at least 95%, or at least 99% of the catalyst has been leached on average.
In certain embodiments, TSP body 30 may have a uniform diamond grain size,
but in other embodiments, the grain size may within the TSP body. For example, in
some embodiments TSP body 30 may contain larger diamond grains near contact
30 surface 100 in order to produce more pores, or larger volume pores, thereby providing
more surface area to contact infiltrant material 50. In certain embodiments, these
larger diamond grains may form an attachment layer (not shown) in TSP body 30. In
other embodiments, diamond density may be less in an attachment layer. Difficulties
in wetting diamond often pose a challenge in attaching TSP body 30 to base 70, so the
lower diamond density may aid attachment by improving wetting of contact surface
100.
5 In still other embodiments, TSP body 30 may contain an attachment layer
formed by a different material, such as a carbide former, particularly W2C , or a
material containing only low amounts of diamond as compared to the TSP body. In
one embodiment, such an attachment layer may be placed on the TSP body prior for
formation of the super abrasive element. Due to the destructive tendencies of
10 leaching, such an attachment layer may be placed on TSP body 30 after it has been
leached. In another embodiment, the attachment layer may be formed during super
abrasive element formation by a separate material layer between matrix powder 40
and TSP body 30. In either embodiment, the attachment layer may be attached to the
TSP body sufficiently to remain intact during use of the super abrasive element, but
15 may offer improved attachment to base 70. For instance, the attachment layer may be
more easily wet by infiltrant material 50, or may form a stronger attachment to
infiltrant material 50 than TSP does.
Matrix powder 40 or 40a may be a powder or any other material suitable to
form base 70 after infiltration with infiltrant material 50, which may function as a
20 binder. In particular embodiments, matrix powder 40 or 40a may be a material
commonly used to form substrates of conventional PCD elements. Matrix powder 40
or 40a may also provide beneficial properties to base 70, such as rigidity, erosion
resistance, toughness, and each of attachment to TSP body 30. For example, it may
be a carbide-containing or carbide-forming powder. Base 70 will typically have a
25 higher content of infiltrant material 50 than conventional PCD element substrates
have of similar materials. As a result, base 70 may be less erosion-resistant than
conventional substrates. Certain powder blends may be used as matrix powder 40 to
improve erosion resistance of base 70. In specific embodiments, powder blends may
contain carbide, tungsten (W), tungsten carbide (WC or W2C), synthetic diamond,
30 natural diamond, chromium (Cr), iron (Fe), nickel (Ni), or other materials able to
increase erosion resistance of base 70. Powder blends may also include copper (Cu),
manganese (Mn), phosphorus (P), oxygen (0), zinc (Zn), tin (Sn), cadmium (Cd), lead
(Pb), bismuth (Bi), or tellurium (Te). Matrix powder can contain any combinations or
mixtures of the above-identified materials.
In some embodiments, matrix powder 40 or 40a may have a substantially
uniform particle size. However, in other embodiments, particle size of matrix powder
5 40 or 40a may vary depending of the desired properties of base 70 or to facilitate
attachment of base 70 to TSP body 30 either by infiltration or mechanical means. For
example, infiltration methods such as those using assembly 10, a layer of matrix
powder 40 with smaller particle size may be placed adjacent to TSP body 30. The
smaller particle size may allow infiltrant material 50 to form a stronger attachment by
10 allowing more infiltrant material 50 to reach contact surface 100. Typically particles
of matrix powder 40 or 40a will be on a micrometer or nanometer scale. For example,
average particle diameter may be greater than or equal to 5 pm, such as 5-6 pm. It
may be much higher, such as 100 pm. These particle sized may represent the average
diameter of particles found in a portion of base 70 extending half of the total length of
15 base 70 from TSP body 30. Overall, particle size of matrix powder 40 or 40a may be
substantially larger than permissible particle size in pre-formed substrates.
Although appropriate materials are commonly in a powder form, in some
embodiments matrix powder 40 or 40a may be substituted with a non-powder material
so long as the material is sufficient to be infiltrated with infiltrant material 50, form
20 base 70, and substantially conform to contact surface 100 of TSP body 30.
Infiltrant material 50 may include any material able to infiltrate matrix
powder 40 or 40 a to form base 70. In hot press methods such as those using
assembly 10a, infiltrant material 50 may be mixed with matrix powder 40a prior to
hot pressing. In infiltration methods such as those using assembly 10, and potentially,
25 but not necessarily also in some hot press methods, infiltrant material 50 may also to
wet contact surface 100 and infiltrate at least a sufficient number of pores located at
contact surface 100 of TSP body 30 to cause bonding of TSP body 30 to base 70 via
infiltrant material 50. In particular embodiments, infiltrant material 50 may be a
material having an affinity for diamond such that it readily wets contact surface 100
30 or is readily drawn into pores via capillary action or a similar attractive effect. In
more specific embodiments, infiltrant material 50 may include a material suitable for
use as a catalyst in PCD formation, such as a Group VIII metal, for example
manganese (Mn) or chromium (Cr). Infiltrant material 50 may also be a carbide or
material used in the formation of carbide, such as titanium (Ti) alloyed with copper
(Cu) or silver (Ag). In certain embodiments, infiltrant material 50 may be a different
material than was used as the catalyst during formation of the PCD later leached to
5 form the TSP body. This allows easy detection of catalyst separate from binder.
However, in other embodiments, the infiltrant material and catalyst may be the same.
In specific embodiments, infiltrant material 50 may be an alloy, such as a
nickel (Ni) alloy or another metal alloy, such as a Group VIII metal alloy.. Benefits
in melt temperature may make alloys suitable as infiltrant materials, even when such
10 alloys would not be suitable as catalyst materials in PCD formation.
After formation of super abrasive element 60, infiltrant material 50 may be
found in base 70, where it may function as a binder. Infiltrant material 50 may also
be found in TSP body 30 near contact surface 100 in filled pores. In some
embodiments, infiltrant material 50 may be substantially confined to contact surface
15 100 and pores that open to that surface. However, in other embodiments, infiltrant
material 50 may also enter pores near contact surface 100. The portion of TSP body
30 containing infiltrant material 50 may form the infiltrant material-containing region
80, while the remainder of the TSP body 30 substantially lacking binder may form
infiltrant-free region 90. According to a specific embodiment, a depth, D to which
20 infiltrant material 50 penetrates the TSP body 30 from contact surface 100 may on
average be any depth sufficient to allow bonding of TSP body 30 to base 70. In
particular embodiments it may be no more than 100 pm. In other particular
embodiments, it may be no more than four grain sizes, no more than two grain sizes,
no more than one grain size, no more than half a grain size, or no more than one
25 quarter a grain size, in which grain size refers to the diamond grains at or near contact
surface 100. In still other embodiments, infiltrant material 50 may only penetrate
exposed pore space on contact surface 100.
Infiltrant material 50 may confer properties on TSP body 30 similar to
properties conferred on a PCD by catalyst. In particular, infiltrant material 50 may
30 decrease the abrasion resistance and thermal stability of regions of the TSP body in
which it is found. In example embodiments, to minimize the negative effects of
infiltrant material 50 on abrasion resistance and thermal stability, it may be
advantageous to decrease or minimize the depth D of infiltrant material-containing
region 80 to the amount sufficient to bond TSP body 30 to base 70.
Without limiting the bonding mechanism of infiltrant material 50, according to
certain embodiments, the manner in which infiltrant material 50 bonds TSP body 30
5 to base 70 may include the formation of a physically continuous matrix of infiltrant
material between TSP body 30 and base 70.
Matrix powder 40 or 40a may be formed into base 70 using any appropriate
formation process. In particular embodiments, the formation process may provide
one-step base formation and attachment, instead of requiring separate formation and
10 attachment steps like some prior processes.
In one embodiment, the formation process may be a one-step infiltration
process. In general, in such a process (and also in any hot press process also relying
on infiltration of TSP body 30 by infiltrant material 50 to attach it to base 70), any
material on contact surface 100 other than diamond may interfere with wetting and
15 attachment by infiltrant material 50, so prior to incorporation in assembly 10, in
certain embodiments, contact surface 100 of TSP body 30 may be cleaned. Assembly
10 may be assembled as described above and then placed in a furnace and heated to a
temperature and for a time sufficient to cause infiltration of matrix powder 40 and
TSP body 30 with infiltrant material 50 and casting of matrix powder 40 into base 70.
20 Specifically, the furnace may be heated to a temperature at or above the infiltration
temperature of infiltrant material 50. The minimum temperature able to allow
infiltration of infiltrant material 50 may be referred to as the infiltration temperature.
The time spent at or above the infiltration temperature may be the minimum amount
required to allow infiltration of matrix powder 40 to form base 70 and attachment of
25 base 70 to TSP body 30. In certain embodiments, the time spent at or above the
infiltration temperature may be 60 seconds or less. In order to prevent oxidation
reactions or contamination of infiltrant material 50 or matrix powder 40 during the
formation process, the process make take place under vacuum or in the presence of an
oxygen-free atmosphere, such as a reducing or inert atmosphere.
30 According to a specific embodiment, infiltrant material 50 may travel through
matrix powder 40 due to attractive forces, such as capillary action. Upon reaching
contact surface 100 of TSP body 30, infiltrant material 50 may wet the surface and
bond to it. In particular embodiments, infiltrant material 50 enter open pores and fill
them to form filled pores. Infiltrant material 50 may be drawn into pores via an
attractive force, such as capillary action. This is particularly true if infiltrant material
50 is selected to have an affinity for diamond.
5 After heating, assembly 10 may be removed from the furnace and cooled to a
temperature below the infiltration temperature. Cooling, in certain embodiments, may
be carefully controlled in order to reduce or minimize any weakening of the
attachment between base 70 and TSP body 30. For instance, it may be managed to
reduce or minimize any residual stresses. Finally, super abrasive element 60 may be
10 removed from mold 20.
According to another embodiment, assembly 10a may be used to form a
superabrasive element 60 via a one-step hot press method. As noted above, in some
embodiments forces generated by hot press methods may provide sufficient
mechanical attachment of TSP body 30 to base 70 that attachment via the infiltration
15 material is not required or is of minimal impact. In such embodiments, TSP body 30
may be shaped so as to facilitate such mechanical attachment. For instance, it may
have a shape shown in FIGURES 4 and 5. In other embodiments, even when a hot
press method is used, attachment of TSP body 30 to base 70 may partially or
substantially rely on infiltration of TSP body 30 with infiltrant material 50. If such
20 embodiments any material on contact surface 100 other than diamond may interfere
with wetting and attachment by infiltrant material 50, such that prior to incorporation
in assembly 1 Oa, contact surface 100 of TSP body 30 may be cleaned.
After cleaning, if conducted, TSP body 30 may be loaded into hot press mold
20a then packed with matrix powder 40a, which may contain both a matrix material
25 and an infiltration material or binder. The mold may then be closed and subjected to
hot pressing at a temperature and pressure sufficient to melt the infiltrant material or
binder and allow it to form substrate 70. In embodiments where infiltrant material
infiltrates TSP body 30, the temperature and pressure may also be sufficient to allow
this infiltration to occur. In certain embodiments, hot pressing may involve a cycle of
30 changing temperature and pressure over time.
According to certain embodiments, hot pressing may be conducted under an
inert or reducing atmosphere to prevent or reduce damage to TSP body 30.
Alternatively, temperature may be carefully controlled to prevent oxidation of TSP
body 30.
Hot pressing may be used to form a single super abrasive element 60 or
multiple assemblies 10a may be processed as the same time to simultaneously form
5 multiple super abrasive elements 60. In either case, each super abrasive element
maybe removed from mold 20a after completion of hot pressing.
In either infiltration process, the temperature and pressure used may be outside
of the traditional diamond-stable region. The temperature and pressures at which
PCD degrades to graphite are known in the art and described in the literature. For
10 instance, the diamond-stable region may be determined through reference to Bundy et
al.. "Diamond-Graphite Equilibrium Line from Growth and Graphitization of
Diamond," J. of Chemical Physics, 35(2):383-391 (1 961), Kennedy and Kennedy,
"the Equilibrium Boundary Between Graphite and Diamond," J. of Geophysical Res.,
81 (1 4): 2467-2470 (1 976), and Bundy, et al., "The Pressure-Temperature Phase and
15 Transformation Diagram for Carbon; Updated through 1994," Carbon 34(2) : 14 1 - 153
(1 996), each of which is incorporated by reference in material part herein. The highly
stable nature of TSP may allow it to withstand temperature and pressures outside of
the diamond-stable region for the time needed to form superabrasive element 60. For
instance, at pressured used in infiltration processes, temperatures may reach as high as
20 1100 "C or 1200 "C.
In general, if pressure is carefully controlled, an infiltrant with a higher melt
temperature may be used, reducing the likelihood of infiltrant melting during
downhole conditions or other harsh conditions.
Although use of temperatures and pressures outside of the diamond stable
25 region is possible, in many embodiments, such as some hot press methods,
temperatures and pressures may be within the diamond stable region. For example,
some hot press techniques may employ temperatures of between 850°C - 900°C,
particularly 870°C.
In addition to causing a decrease in erosion resistance as noted above, the
30 presence of additional infiltrant material 50 in base 70 as compared to similar
amounts of catalyst or binder in a conventional PCD element substrate causes base 70
to be less stiff than a conventional substrate. This may result in increased bending
stresses on TSP body 30 when super abrasive element 60 is in use. In order to
increase the stiffness of base 70, a carbide insert 140 as shown in FIGURE 6 may be
included in base 70. Carbide insert 140 may be formed of a binderless or near
binderless carbide and may be resistant to infiltration by infiltrant material 50.
5 Carbide insert 140 may be placed within matrix powder 40 in assembly 10. After
formation of super abrasive element 60, carbide insert 140 may be present in base 70
in essentially the same configuration as it was placed in matrix powder 40. In
addition to increasing the stiffness of base 70, carbide insert 140 may be exposed on
the non-TSP body end of super abrasive element 60 after grinding and may then serve
10 as an attachment point in a brazing process or a guide for rotation or placement of the
super abrasive element. In an alternative embodiment, the insert may be formed for
another suitable material other than carbide, such as a ceramic.
Super abrasive elements of the current disclosure may be in the form of any
element that benefits from a TSP surface. In particular embodiments they may be
15 cutters for earth-boring drill bits or components of industrial tools. Embodiments of
the current disclosure also include tools containing super abrasive elements of the
disclosure. Specific embodiments include industrial tools and earth-boring drill bits,
such as fixed cutter drill bits. Other specific embodiments include wear elements,
bearings, or nozzles for high pressure fluids.
20 Due to the ability to leach TSP body 30 more than a PCD layer may typically
be leached when bound to a substrate, super abrasive elements of the current
disclosure may be usable in conditions in which more elements with a traditional
leached PCD layer are not. For instance, super abrasive elements may be used at
higher temperatures than similar elements with a traditional leached PCD layer.
25 When super abrasive elements of the current disclosure are used as cutters on
earth-boring drill bits, they may be used in place of any traditional leached PCD
cutter. In many embodiments, they may be attached to the bits via base 70. For
instance, base 70 may be attached to a cavity in the bit via brazing.
When used in cutting portions of a bit, the working surface of the cutter will
30 wear more quickly than other portions of TSP body 30. When a circular cutter, such
as that shown in FIGURE 2 is used, the cutter may be rotated to move the worn TSP
away from the working surface and to move unused TSP to the working surface.
Circular cutters according to the present disclosure may be rotated in this fashion at
least two times and often three times before they are too worn for further use. The
methods of attachment and rotation may be any methods employed with traditional
leached PCD cutters or other methods. Similarly, non-circular cutters may be
5 indexable, allowing their movement to replace a worn working surface without
replacing the entire cutter.
In embodiments using an insert with the shape shown in FIGURE 6 or another
suitable shape, the insert may be used as a guide for alignment of the working surface
such that the working surface will receive additional support from the insert during
10 use of the super abrasive element. For instance, when using an insert in the shape
shown in FIGURE 6, the element may be aligned such that its working surface is
substantially along one of the insert arms and not in between the arms.
In addition to being rotatable, traditional PCD cutters may also be removed
from a bit. This allows worn or broken cutters to be replaced or allows their
15 replacement with different cutters more optimal for the rock formation being drilled.
This ability to replace cutters greatly extends the usable life of the earth boring drill
bit overall and allows it to be adapted for use in different rock formations. Cutters
formed using super abrasive elements according to this disclosure may also be
removed and replaced using any methods employed with traditional leached PCD
20 cutters.
In certain other embodiments, super abrasive elements of the current
disclosure may be used in directing fluid flow or for erosion control in an earth-boring
drill bit. For instance, they may be used in the place of abrasive structures described
in U.S. 7,730,976; U.S. 6,5 10,906; or U.S. 6,843,333, each incorporated by reference
25 herein in material part.
Although only exemplary embodiments of the invention are specifically
described above, it will be appreciated that modifications and variations of these
examples are possible without departing from the spirit and intended scope of the
invention. For example, although Super abrasive elements are discussed in detail
30 other elements containing a similar component, such as leached cubic boron nitride,
and similar method of forming such elements are also possible.

CLAIMS
1. A super abrasive element comprising:
a substantially catalyst-free thermally stable polycrystalline diamond (TSP)
body having pores and a contact surface;
a base adjacent the contact surface of the TSP body; and
a non-catalyst alloy infiltrant material infiltrated in the base and in the pores of
the TSP body at the contact surface.
2. The super abrasive element according to Claim 1, wherein the
substantially catalyst-free TSP body comprises polycrystalline diamond (PCD) from
which at least 85% of the catalyst has been removed to form the pores.
3. The super abrasive element according to Claim 1, wherein the
substantially catalyst-free thermally stable polycrystalline diamond TSP body
comprises an acid-leached TSP body.
4. The super abrasive element according to Claim 3, wherein the acidleached
TSP body comprises a FeC13-acid-leached TSP body.
5. The super abrasive element according to Claim 1, wherein the TSP
body contains diamond grains having an average grain size, and wherein the infiltrant
material is infiltrated in the pores of the TSP body to a depth from the contact surface
of two average grain sizes or less.
6. The super abrasive element according to Claim 1, wherein the contact
surface is a non-planar surface.
7. The super abrasive element according to Claim 1, wherein the base
comprises a material selected from the group consisting of carbide, tungsten, tungsten
carbide, synthetic diamond, natural diamond, or nickel, chromium, iron, copper,
manganese, phosphorus, oxygen , zinc, tin, cadmium, lead, bismuth, tellurium, and
any combinations thereof.
8. The super abrasive element according to Claim 1, wherein super
abrasive element further comprises a carbide insert disposed in the base.
9. The super abrasive element according to Claim 1, wherein the noncatalyst
alloy infiltrant material comprises a Group VIII metal alloy.
10. The super abrasive element according to Claim 1, wherein the super
abrasive element is in the form of a cutter for an earth-boring drill bit.
1 1. A super abrasive element comprising:
a substantially catalyst-free thermally stable polycrystalline diamond (TSP)
body having pores, a contact surface, and diamond grains having an average grain
size;
a base adjacent the contact surface of the TSP body; and
an infiltrant material infiltrated in the base and in the pores of the TSP body at
the contact surface to a depth from the contact surface of two average grain sizes or
less.
12. The super abrasive element according to Claim 11, wherein the
substantially catalyst-free TSP body comprises polycrystalline diamond (PCD) from
which at least 85% of the catalyst has been removed to form the pores.
13. The super abrasive element according to Claim 1 1, wherein the
substantially catalyst-free thermally stable polycrystalline diamond TSP body
comprises an acid-leached TSP body.
14. The super abrasive element according to Claim 13, wherein the acidleached
TSP body comprises a FeC13-acid-leached TSP body.
15. The super abrasive element according to Claim 1 1, wherein the contact
surface is a non-planar surface.
16. The super abrasive element according to Claim 1 1, wherein the base
comprises a material selected from the group consisting of carbide, tungsten, tungsten
carbide, synthetic diamond, natural diamond, or nickel, chromium, iron, copper,
manganese, phosphorus, oxygen , zinc, tin, cadmium, lead, bismuth, tellurium, and
any combinations thereof.
17. The super abrasive element according to Claim 1 1, wherein super
abrasive element further comprises a carbide insert disposed in the base.
18. The super abrasive element according to Claim 1 1, wherein the
infiltrant material comprises a Group VIII metal.
19. The super abrasive element according to Claim 1 1, wherein the super
abrasive element is in the form of a cutter for an earth-boring drill bit.
20. An earth-boring drill bit comprising a cutter, the cutter comprising a
super abrasive element comprising:
a substantially catalyst-free thermally stable polycrystalline diamond (TSP)
body having pores and a contact surface;
a base adjacent the contact surface of the TSP body; and
a non-catalyst alloy infiltrant material infiltrated in the base and in the pores of
the TSP body at the contact surface.
21. The earth-boring drill bit according to Claim 20, wherein the
substantially catalyst-free TSP body comprises polycrystalline diamond (PCD) from
which at least 85% of the catalyst has been removed to form the pores.
22. The earth-boring drill bit according to Claim 20, wherein the
substantially catalyst-free thermally stable polycrystalline diamond TSP body
comprises an acid-leached TSP body.
23. The earth-boring drill bit according to Claim 22, wherein the acidleached
TSP body comprises a FeC13-acid-leached TSP body.
24. The earth-boring drill bit according to Claim 20, wherein the TSP
body contains diamond grains having an average grain size, and wherein the infiltrant
material is infiltrated in the pores of the TSP body to a depth from the contact surface
of two average grain sizes or less.
25. The earth-boring drill bit according to Claim 20, wherein the contact
surface is a non-planar surface.
26. The earth-boring drill bit according to Claim 20, wherein the base
comprises a material selected from the group consisting of carbide, tungsten, tungsten
carbide, synthetic diamond, natural diamond, or nickel, chromium, iron, copper,
manganese, phosphorus, oxygen , zinc, tin, cadmium, lead, bismuth, tellurium, and
any combinations thereof.
27. The earth-boring drill bit according to Claim 20, wherein super
abrasive element further comprises a carbide insert disposed in the base.
28. The earth-boring drill bit according to Claim 20, wherein the noncatalyst
alloy infiltrant material comprises a Group VIII metal alloy.
29. The earth-boring drill bit according to Claim 20, wherein the bit is
fixed-cutter drill bit.
30. The earth-boring drill bit according to Claim 20, wherein the cutter
comprises a rotatable and replaceable cutter.
3 1. An earth-boring drill bit comprising a cutter, the cutter comprising a
super abrasive element comprising:
a substantially catalyst-free thermally stable polycrystalline diamond (TSP)
body having pores, a contact surface, and diamond grains having an average grain
size;
a base adjacent the contact surface of the TSP body; and
an infiltrant material infiltrated in the base and in the pores of the TSP body at
the contact surface to a depth from the contact surface of two average grain sizes or
less.
32. The earth-boring drill bit according to Claim 3 1, wherein the
substantially catalyst-free TSP body comprises polycrystalline diamond (PCD) from
which at least 85% of the catalyst has been removed to form the pores.
33. The earth-boring drill bit according to Claim 3 1, wherein the
substantially catalyst-free thermally stable polycrystalline diamond TSP body
comprises an acid-leached TSP body.
34. The earth-boring drill bit according to Claim 33, wherein the acidleached
TSP body comprises a FeCls-acid-leached TSP body.
35. The earth-boring drill bit according to Claim 3 1, wherein the contact
surface is a non-planar surface.
36. The earth-boring drill bit according to Claim 3 1, wherein the base
comprises a material selected from the group consisting of carbide, tungsten, tungsten
carbide, synthetic diamond, natural diamond, or nickel, chromium, iron, copper,
manganese, phosphorus, oxygen , zinc, tin, cadmium, lead, bismuth, tellurium, and
any combinations thereof.
37. The earth-boring drill bit according to Claim 3 1, wherein super
abrasive element further comprises a carbide insert disposed in the base.
38. The earth-boring drill bit according to Claim 3 1, wherein the infiltrant
material comprises a Group VIII metal.
39. The earth-boring drill bit according to Claim 3 1, wherein the bit is
fixed-cutter drill bit.
40. The earth-boring drill bit according to Claim 3 1, wherein the cutter
comprises a rotatable and replaceable cutter.
4 1. A method of forming a super abrasive element comprising:
assembling an assembly comprising:
a mold having a bottom;
a thermally stable polycrystalline diamond (TSP) body having pores
and a contact surface and located in the bottom of the mold;
a matrix powder disposed adjacent the contact surface and above the
TSP body in the mold; and
an infiltrant material disposed above the matrix powder in the mold;
heating the assembly to a temperature at a pressure and for a time sufficient
for the infiltrant material to infiltrate the matrix powder and pores of the TSP body;
and
cooling the assembly to form a super abrasive element.
42. The method according to Claim 4 1, further comprising forming the
TSP body prior to assembling the assembly.
43. The method according to Claim 41, wherein forming the TSP body
comprises leaching a polycrystalline diamond compact (PCD) having a diamond
matrix and an interstitial matrix containing catalyst to remove the catalyst from the
interstitial matrix and form pores.
44. The method according to Claim 43, wherein leaching comprises
leaching with an acid-based leaching agent comprising FeC13.
45. The method according to Claim 43, further comprising removing at
least 85% of the catalyst from the PCD.
46. The method according to Claim 4 1, further comprising infiltrating at
least pores exposed on the contact surface with infiltrant material.
47. The method according to Claim 41, wherein assembling further
comprises disposing a carbide insert in the matrix powder.
48. The method according to Claim 41, further comprising cleaning
contact surface of the TSP body prior to assembling the assembly.
49. The method according to Claim 4 1, further comprising cooling the
assembly from the bottom.
50. A method of forming a super abrasive element comprising:
assembling an assembly comprising:
a mold having a bottom;
a thermally stable polycrystalline diamond (TSP) body having pores
and a contact surface and located in the bottom of the mold;
a matrix powder disposed adjacent the contact surface and above the
TSP body in the mold; and
an infiltrant material disposed in the matrix powder in the mold;
heating the assembly to a temperature at a pressure and for a time sufficient
for the infiltrant material to infiltrate the matrix powder and pores of the TSP body;
and
cooling the assembly to form a super abrasive element.
5 1. The method according to Claim 50, further comprising forming the
TSP body prior to assembling the assembly.
52. The method according to Claim 50, wherein forming the TSP body
comprises leaching a polycrystalline diamond compact (PCD) having a diamond
matrix and an interstitial matrix containing catalyst to remove the catalyst from the
interstitial matrix and form pores.
53. The method according to Claim 52, wherein leaching comprises
leaching with an acid-based leaching agent comprising FeC13.
54. The method according to Claim 52, further comprising removing at
least 85% of the catalyst from the PCD.
55. The method according to Claim 50, further comprising infiltrating at
least pores exposed on the contact surface with infiltrant material.
56. The method according to Claim 50, wherein assembling further
comprises disposing a carbide insert in the matrix powder.
57. The method according to Claim 50, further comprising cleaning
contact surface of the TSP body prior to assembling the assembly.
58. The method according to Claim 50, further comprising cooling the
assembly from the bottom.