U.S. patent application number 13/720714 was filed with the patent office on 2013-06-20 for methods for manufacturing polycrystalline ultra-hard constructions and polycrystalline ultra-hard constructions.
This patent application is currently assigned to SMITH INTERNATIONAL, INC.. The applicant listed for this patent is SMITH INTERNATIONAL, INC.. Invention is credited to YAHUA BAO, J. DANIEL BELNAP, RONALD K. EYRE, GUOJIANG FAN.
Application Number | 20130152480 13/720714 |
Document ID | / |
Family ID | 48608702 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130152480 |
Kind Code |
A1 |
EYRE; RONALD K. ; et
al. |
June 20, 2013 |
METHODS FOR MANUFACTURING POLYCRYSTALLINE ULTRA-HARD CONSTRUCTIONS
AND POLYCRYSTALLINE ULTRA-HARD CONSTRUCTIONS
Abstract
Polycrystalline ultra-hard constructions are made by subjecting
a sintered ultra-hard body, substantially free of a sintering
catalyst material, to a further HPHT process. The process is
controlled to initially melt and infiltrating a filler material
into the sintered ultra-hard body to form a filler region having
interstitial regions filled with the filler material. The filler
region extends a partial depth into the sintered ultra-hard body
and is formed at a temperature below the melting temperature of an
infiltrant material. Next, the process is controlled to melt and
infiltrate the infiltrant material into the sintered ultra-hard
body to form an infiltrant region that extends a partial depth into
the sintered ultra-hard body. A portion of the filler region and/or
the infiltrant region may be removed to form a thermally stable
region.
Inventors: |
EYRE; RONALD K.; (OREM,
UT) ; BAO; YAHUA; (OREM, UT) ; BELNAP; J.
DANIEL; (LINDON, UT) ; FAN; GUOJIANG; (SALT
LAKE CITY, UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SMITH INTERNATIONAL, INC.; |
HOUSTON |
TX |
US |
|
|
Assignee: |
SMITH INTERNATIONAL, INC.
HOUSTON
TX
|
Family ID: |
48608702 |
Appl. No.: |
13/720714 |
Filed: |
December 19, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61578079 |
Dec 20, 2011 |
|
|
|
Current U.S.
Class: |
51/295 ; 51/307;
51/309 |
Current CPC
Class: |
C22C 26/00 20130101;
B22F 3/02 20130101; B22F 2003/244 20130101; B22F 3/10 20130101;
B22F 2007/066 20130101; B22F 7/062 20130101; B22F 2998/10 20130101;
B22F 2998/10 20130101; B24D 99/005 20130101; B22F 2007/066
20130101; B24D 18/0027 20130101 |
Class at
Publication: |
51/295 ; 51/307;
51/309 |
International
Class: |
B24D 18/00 20060101
B24D018/00 |
Claims
1. A method for making an ultra-hard polycrystalline construction
comprising: subjecting a sintered ultra-hard body that is
substantially free of a catalyst material used to initially sinter
the ultra-hard body at high pressure/high temperature conditions to
a further high pressure/high temperature process to introduce an
infiltrant material, wherein the sintered ultra-hard body comprises
a matrix phase of directly bonded together ultra-hard particles,
and a plurality of substantially empty interstitial regions
disposed within the matrix, wherein the further high pressure/high
temperature process comprises: melting and infiltrating a filler
material into the sintered ultra-hard body to form a filler region
having interstitial regions filled with the filler material, the
filler region extending a partial depth into the sintered
ultra-hard body and being formed at a temperature below the melting
temperature of an infiltrant material and at a pressure below about
3 GPa; and melting and infiltrating the infiltrant material into
the sintered ultra-hard body to form an infiltrant region, wherein
melting and infiltrating the infiltrant material occurs at a
temperature and pressure greater than that used to form the filler
region, and wherein the infiltrant region extends a partial depth
into the sintered ultra-hard body.
2. The method as recited in claim 1, wherein the filler material
has a melting temperature of less than about 1,000.degree. C.
3. The method as recited in claim 1, wherein after melting and
infiltrating the infiltrant material, the sintered ultra-hard body
consists of the filler region and infiltrant region.
4. The method as recited in claim 1, wherein during melting and
infiltrating the infiltrant material, a sufficient population of
the interstitial regions within the sintered ultra-hard body are
filled with either the filler material or the infiltrant material
such that the sintered ultra-hard body remains above the
Berman/Simon diamond-graphite equilibrium line.
5. The method as recited in claim 1, wherein after melting and
infiltrating the infiltrant material less than about 2 percent of
the population of the interstitial regions within the sintered
ultra-hard body are empty.
6. The method as recited in claim 1, wherein after melting and
infiltrating the infiltrant material about 0 to 2 percent of the
population of the interstitial regions within the sintered
ultra-hard body are empty.
7. The method as recited in claim 6, wherein after melting and
infiltrating the infiltrant material about 0 to 1 percent of the
population of the interstitial regions within the sintered
ultra-hard body are empty.
8. The method as recited in claim 6, wherein after melting and
infiltrating the infiltrant material essentially 100 percent of the
interstitial regions are filled.
9. The method as recited in claim 1, further comprising attaching a
substrate to the ultra-hard body.
10. The method as recited in claim 9, wherein the substrate is
attached to the body adjacent the body infiltrant region.
11. The method as recited in claim 1, wherein the filler material
is selected from the group consisting of aluminum, gallium, copper,
zinc, silver, indium, thallium, tin, lead, bismuth, alloys, metal
salts, and mixtures thereof.
12. The method as recited in claim 1, wherein the filler material
is selected from the group consisting of metal salts, carbonates,
fluorides, chlorides, bromides, sulfides and combinations
thereof.
13. The method as recited in claim 11, wherein the filler material
is an alloy which is a eutectic alloy.
14. The method as recited in claim 1, wherein the filler material
comprises tin or bismuth.
15. The method as recited in claim 1, wherein the melting
temperature of the filler material is less than about 700.degree.
C.
16. The method as recited in claim 1, wherein the melting
temperature of the filler material is less than about 300.degree.
C.
17. The method as recited in claim 1, further comprising, after
melting and infiltrating the infiltrant material, treating the
ultra-hard body to remove the filler material from the filler
region to provide a thermally stable region.
18. The method as recited in claim 17, wherein the thermally stable
region contains less than about 12 percent by weight filler
material, based on the total weight of the ultra-hard body.
19. The method as recited in claim 17, wherein the thermally stable
region contains less than about 2 percent by weight filler
material, based on the total weight of the ultra-hard body.
20. The method as recited in claim 1, wherein substantially all the
ultra-hard particles in the ultra-hard body are directly bonded to
one another.
21. The method as recited in claim 1, further comprising placing
the filler material adjacent a working surface of the ultra-hard
body before melting and introducing the filler material.
22. The method as recited in claim 9, wherein the infiltrant
material is provided from the substrate.
23. The method as recited in claim 1, wherein the infiltrant
material comprises one or more Group VIII elements of the Periodic
table, alloys, and mixtures thereof.
24. The method as recited in claim 1, wherein the infiltrant
material and the catalyst material are different.
25. The method as recited in claim 24, wherein the infiltrant
material and the catalyst material both comprise cobalt.
26. The method as recited in claim 1, wherein the ultra-hard
material is diamond, and the matrix phase is intercrystalline
bonded together diamond crystals.
27. The method as recited in claim 1, wherein during melting and
infiltrating the infiltrant material, a substrate is used as a
source to introduce the infiltrant material, wherein the substrate
is different from a substrate used to introduce the catalyst
material initially used to sinter the ultra-hard body.
28. The method as recited in claim 27, wherein the substrate used
as a source for the infiltrant material has a material makeup that
is different from the substrate used to introduce the catalyst
material.
29. The method as recited in claim 17, wherein the thermally stable
region extends a depth of at least about 0.5 mm from a surface of
the ultra-hard body including one or both of a top and side
surface.
30. The method as recited in claim 17, further comprising treating
the ultra-hard body to remove a portion of the infiltrant material
so that the thermally stable region includes a portion of the
infiltrant region.
31. A polycrystalline ultra-hard construction disposed in a high
pressure/high temperature device, the construction comprising: a
sintered ultra-hard body having a material microstructure
comprising a matrix phase of directly bonded together ultra-hard
particles formed at high pressure/high temperature conditions in
the presence of a catalyst material, the ultra-hard body having a
surface and including interstitial regions disposed within the
matrix phase, wherein the interstitial regions within the
ultra-hard body are substantially free of the catalyst material;
wherein the ultra-hard body is at a temperature and pressure
sufficient to melt and infiltrate a filler material into the
ultra-hard body to form a filler region, wherein the pressure is
less than about 3 GPa, the interstitial regions within the filler
region comprising the filler material, and wherein the remaining
interstitial regions in the ultra-hard body are substantially free
of the filler material and the catalyst material; and an infiltrant
material positioned adjacent the ultra-hard body, wherein the
infiltrant material is in a solid state at the pressure and
temperature.
32. The construction as recited in claim 31, wherein the filler
material is selected from the group consisting of aluminum,
gallium, zinc, indium, thallium, tin, lead, bismuth, alloys, metal
salts, and mixtures thereof, wherein the filler region extends into
the ultra-hard body a depth from the surface.
33. The construction as recited in claim 31, wherein the
temperature is less than about 700.degree. C.
34. The construction as recited in claim 31, wherein the pressure
is less than about 2.5 GPa.
35. A polycrystalline diamond construction comprising an ultra-hard
body having a thermally stable region and an infiltrant region that
is formed by the process comprising; subjecting a sintered
ultra-hard body to a high pressure/high temperature process, the
sintered ultra-hard body comprising a matrix phase of
intercrystalline bonded together diamond crystals that extends
throughout the body, the body including a plurality of interstitial
regions disposed within the matrix phase, wherein the interstitial
regions are substantially free of a catalyst material that was used
to initially form the sintered ultra-hard body, the high
pressure/high temperature process comprises; melting and
infiltrating a filler material at a first temperature and first
pressure condition to form a filler region in the ultra-hard body,
wherein the interstitial regions within the filler region comprise
the filler material, the first pressure condition being less than
about 3 GPa, the filler region extending into the ultra-hard body a
partial depth from an ultra-hard body first surface; melting and
infiltrating an infiltrant material at a second temperature and
second pressure condition to form an infiltrant region in the
ultra-hard body, wherein the interstitial regions within the
infiltrant region comprise the infiltrant material, the second
temperature condition being greater than the first temperature
condition, and the second pressure condition being greater than the
first pressure condition, wherein the ultra-hard body comprising
the filler region and the infiltrant region at the second
temperature and second pressure condition is in a diamond stable
state above the Berman/Simon diamond-graphite equilibrium line; and
treating the ultra-hard body comprising the filler region and
infiltrant region to remove the filler material from a population
of the interstitial regions within the filler region to form a
thermally-stable region that is substantially free of the filler
material, and that extends a depth from the ultra-hard body
surface.
36. The construction as recited in claim 35, wherein the ultra-hard
body comprises the infiltrant region and the thermally stable
region, and is substantially free of the filler region.
37. The construction as recited in claim 36, wherein the thermally
stable region extends a depth into the infiltrant region, wherein
the interstitial regions within the thermally stable region are
substantially free of the infiltrant material.
38. The construction as recited in claim 35, wherein the filler
material is an alloy which is a eutectic alloy.
39. The construction as recited in claim 35, wherein the filler
material comprises tin or bismuth.
40. The construction as recited in claim 35, wherein the melting
temperature of the filler material is less than about 700.degree.
C.
41. The construction as recited in claim 35, wherein the melting
temperature of the filler material less than about 300.degree.
C.
42. The construction as recited in claim 35, wherein the infiltrant
material comprises one or more Group VIII elements of the Periodic
Table, alloys, and mixtures thereof.
43. The construction as recited in claim 35, wherein the infiltrant
material and the catalyst material are different.
44. The construction as recited in claim 43, wherein the infiltrant
material and the catalyst material both comprise cobalt.
45. The construction as recited in claim 35, wherein the surface
comprises a working surface including a top surface and a side
surface of the ultra-hard body, and wherein the thermally stable
region extends a depth of at least about 0.5 mm from both the top
and side surfaces.
46. The construction as recited in claim 45, further comprising a
beveled cutting edge interposed between the top and side surfaces,
and wherein the thermally stable region extends a depth
therefrom.
47. The construction as recited in claim 35, further comprising a
substrate attached to the ultra-hard body adjacent the infiltrant
region.
48. The construction as recited in claim 35, wherein the ultra-hard
body has a thickness of greater than about 1 mm.
49. A method for making an ultra-hard polycrystalline construction
comprising: subjecting a plurality of ultra-hard particles to a
high pressure/high temperature condition in the presence of a
catalyst material to form a polycrystalline ultra-hard material
comprising a matrix phase of directly bonded together ultra-hard
particles, and a plurality of interstitial regions disposed within
the matrix phase which include the catalyst material; treating the
polycrystalline ultra-hard material to remove the catalyst material
therefrom to form an ultra-hard body that is substantially free of
the catalyst material used to initially form the polycrystalline
ultra-hard material; introducing a filler material, wherein the
filler material fills a population of the plurality of interstitial
regions of the ultra-hard body in a first region extending a depth
from a surface of the ultra-hard body, wherein the first region is
formed at a first temperature and at a pressure of less than about
3 GPa; introducing an infiltrant material into the ultra-hard body
comprising the first region at a temperature greater than the first
temperature, wherein the infiltrant material fills a population of
the plurality of interstitial regions of the ultra-hard body in a
second region, wherein the second region is formed while the
ultra-hard body is in a diamond stable state above the Berman/Simon
diamond-graphite equilibrium line; and attaching a substrate to the
ultra-hard body.
50. The method of claim 49, further, comprising treating the
ultra-hard body to remove at least a portion of the filler material
therefrom to form a thermally stable region that is substantially
free of the filler material.
51. The method of claim 50, further comprising treating the
ultra-hard body to remove at least a portion of the infiltrant
material therefrom to form the thermally stable region that is
substantially free of the infiltrant material.
52. The method as recited in claim 49, wherein the thermally stable
region extends a depth of less than about 0.2 mm from the
surface.
53. The method as recited in claim 49, wherein the filler material
is selected from the group consisting of aluminum, gallium, zinc,
indium, thallium, tin, lead, bismuth, carbonates, sulfates,
hydroxides, chlorides, alloys, metal salts, and mixtures thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/578,079 filed Dec. 20, 2011, which
is incorporated herein by reference in its entirety.
FIELD
[0002] Improved methods for forming polycrystalline ultra-hard
constructions, and polycrystalline ultra-hard constructions
resulting from such improved methods, are disclosed herein.
BACKGROUND
[0003] The existence and use polycrystalline diamond material types
for forming tooling, cutting and/or wear elements is well known in
the art. For example, polycrystalline diamond (PCD) is known to be
used as cutting elements to remove metals, rock, plastic and a
variety of composite materials. Such known polycrystalline diamond
materials have a microstructure characterized by a polycrystalline
diamond matrix first phase, that generally occupies the highest
volume percent in the microstructure and that has the greatest
hardness, and a plurality of second phases, that are generally
filled with a solvent catalyst material used to facilitate the
bonding together of diamond particles, grains or crystals together
to form the polycrystalline matrix first phase during
sintering.
[0004] PCD known in the art is formed by combining diamond grains
(that will create the polycrystalline matrix first phase) with a
suitable solvent catalyst material (that will create the second
phase) to form a mixture. The solvent catalyst material can be
provided in the form of powder and mixed with the diamond grains or
can be infiltrated into the diamond grains during high
pressure/high temperature (HPHT) sintering. The diamond grains and
solvent catalyst material are sintered at extremely high
pressure/high temperature process conditions, during which time the
solvent catalyst material promotes desired intercrystalline
diamond-to-diamond bonding between the grains, thereby forming a
PCD structure.
[0005] Solvent catalyst materials used for forming conventional PCD
include solvent metals from Group VIII of the Periodic table, with
cobalt (Co) being the most common. Conventional PCD can comprise
from about 85 to 95% by volume diamond and a remaining amount being
the solvent metal catalyst material. The solvent catalyst material
is present in the microstructure of the PCD material within
interstices or interstitial regions that exist between the directly
bonded together diamond particles and/or along the surfaces of the
diamond particles.
[0006] The resulting PCD structure produces enhanced properties of
wear resistance and hardness, making PCD materials extremely useful
in aggressive wear and cutting applications where high levels of
wear resistance and hardness are desired. Industries that utilize
such PCD materials for cutting, e.g., in the form of a cutting
element, include automotive, oil and gas, aerospace, nuclear and
transportation to mention only a few.
[0007] For use in the oil production industry, such PCD cutting
elements are provided in the form of specially designed cutting
elements such as shear cutters that are configured for attachment
with a subterranean drilling device, e.g., a shear or drag bit.
Thus, such PCD shear cutters are used as the cutting elements in
shear bits that drill holes in the earth for oil and gas
exploration. Such shear cutters generally comprise a PCD body that
is joined to substrate, e.g., a substrate that is formed from
cemented tungsten carbide. The shear cutter is manufactured using
an HPHT process that utilizes cobalt as a catalytic second phase
material that facilitates liquid-phase sintering between diamond
particles to form a single interconnected polycrystalline matrix of
diamond with cobalt dispersed throughout the matrix.
[0008] The shear cutter is attached to the shear bit via the
substrate, usually by a braze material, leaving the PCD body
exposed as a cutting element to shear rock as the shear bit
rotates. High forces are generated at the PCD/rock interface to
shear the rock away. In addition, high temperatures are generated
at this cutting interface, which shorten the cutting life of the
PCD cutting edge. High temperatures incurred during operation cause
the cobalt in the diamond matrix to thermally expand and even
change phase, which thermal expansion is known to cause the diamond
crystalline bonds within the microstructure to be broken at or near
the cutting edge thereby also operating to reduce the life of the
PCD cutter. Also, in high temperature oxidizing cutting
environments, the cobalt in the PCD matrix will facilitate the
conversion of diamond back to graphite, which is also known to
radically decrease the performance life of the cutting element.
[0009] Attempts in the art to address the above-noted limitations
have largely focused on the solvent catalyst material's degradation
of the PCD construction by catalytic operation, and have involved
removing the catalyst material from the PCD construction for the
purpose of enhancing the service life of PCD cutting elements. For
example, it is known to treat the PCD body to remove the solvent
catalyst material therefrom, which treatment has been shown to
produce a resulting diamond body having enhanced cutting
performance. One known way of doing this involves at least a
two-stage technique of first forming a conventional sintered PCD
body, by combining diamond grains and a solvent catalyst material
and subjecting the same to HPHT process as described above, and
then removing the solvent catalyst material therefrom, e.g., by
acid leaching process.
[0010] As discussed in US 2008/0230280 A1 and US 2008/0223623 A1,
an approach to providing a thermally stable PCD construction is to
form a PCD body during a HPHT sintering process and then remove
substantially all of the solvent catalyst material from the PCD
body so that the remaining thermally stable PCD (TSP) body
comprises essentially a matrix of intercrystalline bonded together
diamond crystals with no other material occupying the interstitial
regions between the diamond crystals. While such a TSP body may
display improved thermal properties, it now lacks toughness that
may make it unsuited for particular high-impact cutting and/or wear
applications.
[0011] Therefore, it is known to infiltrate the TSP with an
infiltrant material, for example selected from Group VIII elements
from the Periodic Table, such as Co, Ni and/or Fe. The infiltrant
material may be provided via migration by re-bonding the treated
PCD body to a substrate during a HPHT re-bonding process, wherein
the infiltrant material present as a constituent in the substrate
liquefies and infiltrates into the TSP body, also attaching the
body to the substrate. After infiltration of the infiltrant
material, the infiltrated TSP body is treated again, this time, to
remove the infiltrant material from a surface of the PCD body.
[0012] Such reattached treated PCD (or TSP) cutting elements
comprising such infiltrants can fail prematurely during use.
Without wishing to be bound by any particular theory, it is
believed that the failure of such reattached PCD cutting elements
can be due to insufficient migration of the infiltrant material
into the treated PCD body during the infiltration process (e.g.,
re-bonding process). Insufficient migration of the infiltrant
material produces residual porosity in the infiltrated TSP body. If
the pores or voids created from treating the PCD body to remove the
catalyst material are partially infiltrated, or otherwise not
properly infiltrated during the infiltration process, the empty
pores can weaken the body and create structural flaws in the
microstructure leading to premature failure of the cutting element.
Partial infiltration, thus makes the PCD body vulnerable to
cracking during finishing operations such as lapping or grinding,
and also can make re-treating the PCD body to remove infiltrant
material more difficult, which can weaken the bond between the PCD
body and an attached substrate.
[0013] Insufficient migration of the infiltrant during the
infiltration process can be due to the sluggish infiltration
kinetics of the infiltrant material (e.g., cobalt) and the porosity
and/or the small pores of the PCD body. For example, the
infiltration of an infiltrant such as cobalt from carbide, e.g.,
present as a constituent in a WC--Co substrate, is very difficult
such that in many cases the cobalt is not able to fully infiltrate
the PCD body during HPHT processing, leading to the degradation of
diamond in the partially infiltrated region, and operating to
reduce the wear resistance of the PCD body.
[0014] Further, when the treated PCD body is taken to pressure and
heated to melt the infiltrant (e.g., cobalt), there is a period of
time which the diamond in the pore space of the body is out of the
diamond stable region, i.e., there is temperature but insufficient
pressure. This situation can cause damage to the diamond structure
and weaken the diamond bonds, operating to further reduce the wear
resistance, strength and service life of the PCD body and cutting
element formed therefrom.
[0015] As discussed in US 2010/0320006 A1, one approach to
improving the infiltration of the infiltrant material is to
increase the porosity in the treated PCD body near the source of
the infiltrant material (e.g., substrate). While such approach may
operate to facilitate the migration of the infiltrant into the PCD
body, the increase in porosity decreases the overall diamond
density or diamond volume of the PCD body, thereby operating to
weaken the structure of the PCD body and reduce the service life of
the cutting element formed therefrom.
[0016] It is, therefore, desirable to provide polycrystalline
ultra-hard constructions, and methods for making the same,
engineered in a manner that not only have improved thermal
characteristics to provide an improved degree of thermal stability
during use, but that do so in a manner that maintains the desired
wear resistance and diamond density or diamond volume, thereby
minimizing or eliminating known mechanisms of premature failure as
compared to conventional PCD constructions. It is further desired
that such polycrystalline ultra-hard constructions be engineered in
a manner that facilitates the manufacturing process, to provide
manufacturing efficiencies when compared to conventional PCD
constructions.
SUMMARY
[0017] Polycrystalline ultra-hard constructions prepared according
to principles of this disclosure are made by subjecting a sintered
ultra-hard body that is substantially free of a catalyst material
used to initially sinter the ultra-hard body at high pressure/high
temperature conditions to a further high pressure/high temperature
process to introduce an infiltrant material. The sintered
ultra-hard body comprises a matrix phase of directly bonded
together ultra-hard particles, and a plurality of substantially
empty interstitial regions disposed within the matrix. In an
example embodiment, the ultra-hard material is diamond, and the
matrix phase is intercrystalline bonded together diamond
crystals.
[0018] In an example embodiment, the further high pressure/high
temperature process is performed in a controlled manner to minimize
damage to the matrix phase. In such example embodiment, the process
comprises melting and infiltrating a filler material into the
sintered ultra-hard body to form a filler region having
interstitial regions filled with the filler material. In an example
embodiment, the filler region extends a partial depth into the
sintered ultra-hard body and is formed at a temperature below the
melting temperature of an infiltrant material and at a pressure
below about 3 GPa. The filler material may be placed adjacent a
surface, e.g., a working surface, of the ultra-hard body before
melting and introducing the filler material.
[0019] In an example embodiment, the filler material has a melting
temperature of less than about 1,000.degree. C., may have a melting
temperature of less than about 700.degree. C., and in some
embodiments may have a melting temperature of less than about
300.degree. C. The filler material may be selected from the group
including aluminum, gallium, copper, zinc, silver, indium,
thallium, tin, lead, bismuth, alloys, metal salts, carbonates,
fluorides, chlorides, bromides, sulfides and mixtures thereof. In
an example embodiment, the filler material may be an alloy which is
a eutectic alloy.
[0020] The process further comprises next melting and infiltrating
the infiltrant material into the sintered ultra-hard body, now
comprising the filler region, to form an infiltrant region. In an
example embodiment, the melting and infiltrating of the infiltrant
material occurs at a temperature and pressure greater than that
used to form the filler region. The infiltrant region extends a
partial depth into the sintered ultra-hard body. Thus, after
melting and infiltrating the infiltrant material, the sintered
ultra-hard body consists of the filler region and infiltrant
region.
[0021] In an example embodiment, during melting and infiltrating
the infiltrant material, a sufficient population of the
interstitial regions within the sintered ultra-hard body is filled
with either the filler material or the infiltrant material to
ensure that the sintered ultra-hard body remains above the
Berman/Simon diamond-graphite equilibrium line. For example, after
melting and infiltrating the infiltrant material less than about 2
percent of the population of the interstitial regions within the
sintered ultra-hard body are empty, preferably about 0 to 2 percent
of the population of the interstitial regions within the sintered
ultra-hard body are empty, and more preferably about 0 to 1 percent
of the population of the interstitial regions within the sintered
ultra-hard body are empty. In an example, after melting and
infiltrating the infiltrant material essentially 100 percent of the
interstitial regions are filled.
[0022] During the further high pressure/high temperature process, a
substrate may be attached to the ultra-hard body, e.g., the
substrate may be the source of the infiltrant, and may be attached
to the attached to the body adjacent the body infiltrant
region.
[0023] In an example embodiment, after the infiltrant region is
formed, the ultra-hard body may be treated to remove all or a
portion of the filler material from the filler region to provide a
thermally stable region. The thermally stable region may comprise
less than about 12 percent by weight filler material, based on the
total weight of the ultra-hard body, and in some embodiments the
thermally stable region may comprise less than about 2 percent by
weight filler material, based on the total weight of the ultra-hard
body. In an example embodiment, the thermally stable region extends
a depth of at least about 0.5 mm from a surface of the ultra-hard
body including one or both of a top and side surface. Additionally,
the thermally stable region may include a portion of the infiltrant
region.
[0024] Polycrystalline ultra-hard constructions made in this manner
display improved thermal characteristics to provide an improved
degree of thermal stability during use, when compared to
conventional polycrystalline ultra-hard constructions, and do so in
a manner that maintains the desired wear resistance and diamond
density or diamond volume, thus minimizing or eliminating known
mechanisms of premature failure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and other features and advantages of polycrystalline
ultra-hard constructions and methods of making the same as
disclosed herein will be appreciated as the same becomes better
understood by reference to the following detailed description when
considered in connection with the accompanying drawings
wherein:
[0026] FIG. 1 illustrates a phase diagram for diamond;
[0027] FIG. 2 illustrates a cross-sectional schematic side view of
an ultra-hard construction according to one or more embodiments of
the present disclosure;
[0028] FIG. 3 illustrates a cross-sectional schematic side view of
an ultra-hard construction according to one or more embodiments of
the present disclosure;
[0029] FIG. 4A is a schematic view of a region taken from a
polycrystalline diamond body comprising an infiltrant material
disposed interstitially between bonded together diamond particles
according to methods disclosed herein;
[0030] FIG. 4B is a schematic view of a region taken from a
polycrystalline diamond body that is substantially free of the
infiltrant material of FIG. 4A according to methods disclosed
herein;
[0031] FIGS. 5A to 5C are cross-sectional schematic side views of
polycrystalline diamond constructions of one or more embodiments of
the present disclosure during different stages of formation;
[0032] FIGS. 6A to 6C are cross-sectional schematic side views of
polycrystalline diamond constructions of one or more embodiments of
the present disclosure during different stages of formation;
[0033] FIG. 7 is a perspective side view of an insert comprising a
polycrystalline diamond construction as disclosed herein;
[0034] FIG. 8 is a perspective side view of a roller cone drill bit
comprising a number of the inserts of FIG. 7;
[0035] FIG. 9 is a perspective side view of a percussion or hammer
bit comprising a number of inserts of FIG. 7;
[0036] FIG. 10 is a schematic perspective side view of a diamond
shear cutter comprising a polycrystalline diamond construction as
disclosed herein; and
[0037] FIG. 11 is a perspective side view of a drag bit comprising
a number of the shear cutters of FIG. 10.
DETAILED DESCRIPTION
[0038] Ultra-hard constructions of the present disclosure, for
example polycrystalline diamond constructions, have a material
microstructure comprising a polycrystalline matrix first phase that
is formed from bonded together ultra-hard particles, such as
directly bonded together diamond particles (grains or crystals),
i.e., intercrystalline diamond. The ultra-hard body further
includes interstitial regions disposed between the ultra-hard
particles. The interstitial regions initially contain the catalyst
material utilized to form the ultra-hard body during HPHT
processing. The ultra-hard body is treated to remove the catalyst
material from throughout the body. An infiltrant material is then
introduced into at least one region of the treated ultra-hard body,
and a filler material is also introduced into at least one other
region of the treated ultra-hard body.
[0039] The resulting ultra-hard body comprises at least one region
of the body containing a population of interstitial regions filled
with an infiltrant material (infiltrant region), and at least one
other region of the body containing a population of interstitial
regions filled with a filler material (filler region). The filler
material has a melting temperature that is lower than the
infiltrant material. In one or more embodiments, the filler
material may be non-reactive or inert to the ultra-hard body. In
one or more embodiments, at least a portion of the infiltrant
material may be provided from a substrate attached to the
ultra-hard body during a re-bonding process, thereby forming a
polycrystalline ultra-hard compact construction. However,
polycrystalline ultra-hard constructions of the present disclosure
may be provided in the form of a polycrystalline ultra-hard body
that may or may not be attached to a substrate.
[0040] Use of a lower melting temperature filler material to
infiltrate at least one region of the polycrystalline ultra-hard
body provides for improved infiltration of the ultra-hard body by
both the infiltrant material and the filler material. Having
un-infiltrated or partially infiltrated interstitial regions
present during infiltration of the treated ultra-hard body creates
a region within the ultra-hard material, for example diamond, that
is exposed to ultra high temperatures without sufficient high
pressure, e.g., during HPHT processing.
[0041] Lack of adequate filler or infiltrant, e.g., metal or salt,
within the interstitial regions during such HPHT processing results
in insufficient pressure being experienced within these regions,
which shifts the diamond out of the diamond stable region and into
the graphite region of the phase diagram as illustrated in FIG. 1.
Localized graphitization of the diamond weakens the diamond
material and ultra-hard body formed therefrom, which can lead to
unsatisfactory performance and reduced service life when placed
into an end-use application. Polycrystalline ultra-hard
constructions, prepared according to principles of the present
disclosure are substantially free of interstitial regions that are
un-infiltrated or partially infiltrated through the use of the
infiltrant and filler, thereby producing an ultra-hard body
displaying improved properties of thermal stability, wear
resistance, impact resistance and/or toughness when compared known
PCD constructions.
[0042] In one or more embodiments of the present disclosure, the
ultra-hard body comprising at least one infiltrant region and at
least one filler region may be further treated to remove the filler
material from a population of the interstitial regions of the body,
thereby forming a thermally stable region with interstitial regions
that may be substantially free of the filler material, for example
substantially empty interstitial regions.
[0043] As the interstitial regions (pores) can be very small,
especially within a sintered ultra-hard body subjected to an
additional HPHT process, the use of a filler material as described
herein allows for better infiltration into the ultra-hard body and
for more complete pore filling than with the use of an infiltration
material, e.g., such as one selected from Group VIII of the
Periodic table like Co, Ni and/or Fe, due partially to the lower
viscosity of the filler material. As discussed above, the improved
infiltration provided by the filler material operates to reduce the
amount of ultra-hard material exposed to HPHT conditions outside
the stable region due to unfilled pores that cause the pressure in
such region to fall below the diamond stable pressure.
[0044] Additionally, using the filler material allows for deeper
infiltration and penetration into the ultra-hard body from a
working surface. Additionally, the filler material is more easily
removed as compared to conventional infiltrant materials, such as
those disclosed above, thereby enabling deeper leach depths to be
obtained without the associated increase in leach time and
difficulty. Additionally, use of the filler material enables
removal by techniques different from and/or more efficient than
those associated with catalyst and infiltrant materials. For
example, filler materials as disclosed herein may be drawn out of
the ultra-hard body by heat, such as in the case of the filler
material being tin, in which case a copper disc can be placed
adjacent the ultra-hard body to melt the tin and draw the tin out
of the body and onto the disc.
[0045] As used herein, the term "ultra-hard" is understood to refer
generally to materials having a Vickers hardness of greater than
about 4,000, including but not limited to materials such as
diamond, cubic boron nitride and the like.
[0046] As used herein, the term "working surface" refers to the
surface or surfaces of the ultra-hard body intended to engage the
formation during drilling. The working surface may include at least
a portion of the top surface, side surface, cutting edge and
combinations thereof.
[0047] As used herein, the term "depth" refers to the depth within
the PCD body as measured inwardly perpendicular from the surface of
interest of the body to the targeted interface (i.e., the boundary
between regions within the PCD body).
[0048] As used herein, the term "polycrystalline diamond" refers to
a material that has been formed at high pressure/high temperature
(HPHT) conditions that has a material microstructure comprising a
matrix phase of bonded-together diamond particles. The material
microstructure further includes a plurality of interstitial regions
that are disposed between the diamond particles. A catalyst
material occupies the interstitial regions after the diamond powder
is subjected to a HPHT sintering process.
[0049] As used herein, a plurality of items, structural elements,
compositional elements and/or materials may be presented in a
common list for convenience. However, these lists should be
construed as though each member of the list is individually
identified as a separate and unique member. Thus, no individual
member of such list should be construed as a de facto equivalent of
any other member of the same list solely based on their
presentation in a common group without indications to the
contrary.
[0050] Concentrations, quantities, amounts, and other numerical
data may be presented herein in a range format. It is to be
understood that such range format is used merely for convenience
and brevity and should be interpreted flexibly to include not only
the numerical values explicitly recited as the limits of the range,
but also to include all the individual numerical values or
sub-ranges encompassed within that range as if each numerical value
and sub-range is explicitly recited. For example, a numerical range
of 1 to 4.5 should be interpreted to include not only the
explicitly recited limits of 1 to 4.5, but also include individual
numerals such as 2, 3, 4 and sub-ranges such as 1 to 3, 2 to 4,
etc. The same principle applies to ranges reciting only one
numerical value, such as "at most 4.5," which should be interpreted
to include all of the above-recited values and ranges. Further,
such an interpretation should apply regardless of the breadth of
the range or the characteristic being described.
[0051] Polycrystalline diamond (PCD) useful for making ultra-hard
constructions as disclosed herein may be formed by conventional
methods of subjecting precursor diamond grains or powder to HPHT
sintering conditions in the presence of a catalyst material, e.g.,
a solvent metal catalyst, that functions to facilitate the direct
bonding together of the diamond grains at temperatures of between
about 1,350 to 1,500.degree. C., and pressures of 5,000 MPa or
higher. Suitable catalyst materials useful for making PCD include
those metals identified in Group VIII of the Periodic table (CAS
version in the CRC Handbook of Chemistry and Physics 75.sup.th
edition, front cover), such as Co, Ni, Fe and combinations
thereof.
[0052] As used herein, the term "thermal characteristics" is
understood to refer to characteristics that impact the thermal
stability of the resulting polycrystalline construction, which can
depend on such factors as the relative thermal compatibilities such
as thermal expansion properties, of the materials occupying and/or
forming the different construction material phases.
[0053] As used herein, the term "catalyzing material" refers to a
material that may be used to initially form the ultra-hard material
body (e.g., polycrystalline diamond body).
[0054] As used herein, the term "infiltrant material" is understood
to refer to materials other than the catalyst material that was
used to initially form or sinter the ultra-hard material body, and
may include materials identified in Group VIII of the Periodic
table that have subsequently been introduced into the sintered
ultra-hard material body after the catalyst material used to
initially form the same has been removed therefrom. Additionally,
the term "infiltrant material" is not intended to be limiting on
the particular method or technique used to introduce such material
into the already-formed ultra-hard material body.
[0055] In one or more embodiment, the diamond body comprises a
first region (infiltrant region) that includes an infiltrant
material. The infiltrant material may be a Group VIII material. The
infiltrant material is disposed within a population of the
interstitial regions within the first region. In an example
embodiment, the first region of the diamond body is positioned
remote from a diamond body surface, e.g., a working surface. The
diamond body includes a second region (filler region) that extends
a depth from the diamond body surface, e.g., a working surface. In
one or more embodiments, the second region may be positioned
adjacent the first region. In this embodiment, it is understood
that there may not be a distinct interface between the first and
second region but there may be a zone of intermixing between the
infiltrant material and the filler material along the interface.
The major portion of the second region comprises interstitial
regions that are substantially free of the infiltrant material and
contain the filler material. In an example embodiment, the second
region extends a depth from one or more surfaces of the body
including top, cutting edge and/or side surfaces, which may or may
not be working surfaces.
[0056] In the one or more embodiments, where the diamond body is
further treated to remove the filler material therefrom, the
diamond body comprises a third region (thermally stable region)
that extends a depth from the diamond body surface, e.g., a working
surface. In one or more embodiments, the third region may extend a
depth into the second region (filler region).
[0057] As illustrated in FIG. 2, a PCD body 211 is formed
containing a first region (infiltrant region) 222 and a second
region (filler region) 233, wherein the first region extends a
depth from one body surface inwardly towards the body, and the
second region extends a depth from another body surface inwardly
towards the body. The PCD body is subsequently treated to form a
third region (thermally stable region) 244, wherein the
interstitial regions within the third region are substantially
empty, and wherein the third region extends a depth from the same
body surface as the second region. In one or more embodiments, the
third region 244 may extend a depth through the second region
(filler region) and into the first region (infiltrant region). If
desired, the third region may be contained to a partial or full
depth of the second region, i.e., without extending into the first
region.
[0058] As illustrated in FIG. 3, a PCD body 311 is formed
containing a first region (infiltrant region) 322 and a second
region (filler region) 333. The PCD body is subsequently treated to
form a third region (thermally stable region) 344 extending through
the second region (filler region) 333 and into a portion of the
first region (infiltrant region) 322 forming a fourth region of
infiltrant material 355. The interface between the first region and
the second region is indicated by a dashed line 366. In such
embodiment, the interstitial regions disposed within the fourth
region are substantially empty.
[0059] In one or more embodiments, polycrystalline diamond
constructions as disclosed herein may include a substrate that is
attached to the diamond body to form a polycrystalline diamond
compact construction. In an example embodiment, the substrate may
be attached to the diamond body adjacent the first region. The
substrate that is ultimately attached to the diamond body may
provide at least a portion of (for example, a major portion of) the
infiltrant material and may be made from the same or different
material as that which may have been used as a source of the
catalyst material during the initial process of forming the diamond
bonded matrix phase. Example substrate materials useful for
providing the infiltrant material include those conventionally used
to form PCD such as cermets, and in an example embodiment cemented
tungsten carbide.
[0060] FIG. 4A schematically illustrates an infiltrant region 10 of
a polycrystalline diamond construction prepared according to one or
more embodiments of the present disclosure that includes the
infiltrant material. Specifically, the region 10 includes a
material microstructure comprising a plurality of bonded together
diamond particles 12, forming an intercrystalline diamond matrix
first phase, and the infiltrant material 14 that is disposed in the
plurality of interstitial regions existing between the bonded
together diamond particles and/or that are attached to the surfaces
of the diamond particles. For purposes of clarity, it is understood
that the region 10 of the polycrystalline construction is one taken
from a PCD body after it has been modified in accordance with the
present disclosure to: 1) remove the catalyst material that was
used to initially form/sinter the PCD body; and 2) fill a
population of the interstitial regions with an infiltrant material.
If desired, the region 10 illustrated in FIG. 4A can be that of a
filler region, wherein the material disposed within the
interstitial regions is filler material rather than infiltrant
material.
[0061] FIG. 4B schematically illustrates a thermally stable region
22 of a polycrystalline diamond construction prepared according to
one or more embodiments of the present disclosure that is
substantially free of any infiltrant material or filler material.
Like the polycrystalline diamond construction region illustrated in
FIG. 4A, the region 22 includes a material microstructure
comprising the plurality of bonded together diamond particles 24,
forming the intercrystalline diamond matrix first phase. Unlike the
region 10 illustrated in FIG. 4A, this region of the diamond body
22 has been modified to remove any infiltrant material or filler
material from the plurality of interstitial regions and, thus
comprises a plurality of interstitial regions 26 that are
substantially empty or free of the infiltrant material or the
filler material. Again, it is understood that the region 22 of the
polycrystalline diamond construction is one taken from a diamond
body after it has been modified in accordance with the present
disclosure to: 1) remove the catalyst material that was used to
initially form the PCD body therefrom; 2) infiltrate the
interstitial regions with infiltrant material or filler material;
and 3) remove the infiltrant or filler material from the
interstitial regions.
[0062] FIGS. 5A, 5B, and 5C each schematically illustrate an
example embodiment polycrystalline diamond construction 30 as
disclosed herein at different stages of formation. FIG. 5A
illustrates a first stage of formation, starting with a
conventional PCD body 32 in its initial form after sintering by
conventional HPHT sintering process. At this early stage, the PCD
body 32 comprises a polycrystalline diamond matrix phase and a
solvent catalyst metal material, such as cobalt, used to form the
diamond matrix phase and that is disposed within the interstitial
regions between the bonded together diamond particles forming the
matrix phase. The solvent metal catalyst material may be added to
the precursor diamond grains or powder as a raw material powder
prior to sintering, may be contained within the diamond grains or
powder, or may be infiltrated into the diamond grains or powder
during the sintering process from a substrate containing the
solvent metal catalyst material and that is placed adjacent the
diamond powder and exposed to the HPHT sintering conditions. In an
example embodiment, the solvent metal catalyst material is provided
from a substrate 34, e.g., a WC--Co substrate, during the HPHT
sintering process.
[0063] Diamond grains useful for forming the PCD body include
synthetic or natural diamond powders having an average diameter
grain size in the range of from submicrometer in size to 100
micrometers, and more preferably in the range of from about 0.5 or
sub micron to 80 micrometers. The diamond powder may contain grains
having a mono or multi-modal particle size distribution. In the
event that diamond powders are used having differently sized
grains, the diamond grains are mixed together by conventional
process, such as by ball or attrittor milling or dry mixing methods
for as much time as necessary to ensure good uniform distribution.
The PCD body may be formed from a single diamond powder or may be
formed from multiple layers of diamond powders which may provide
for a gradual or step-wise gradient in one or more properties
within the sintered PCD body such as diamond density, average
diamond grain size, catalyst material content, which can provide a
desired change or level of strength and thermal abrasion
properties.
[0064] As noted above, the diamond powder may be combined with a
desired solvent metal catalyst powder to facilitate diamond bonding
during the HPHT process and/or the solvent metal catalyst may be
provided by infiltration from a substrate positioned adjacent the
diamond powder during the HPHT process. Suitable solvent metal
catalyst materials useful for forming the PCD body include those
metals selected from Group VIII elements of the Periodic table. An
example solvent metal catalyst is cobalt (Co).
[0065] The diamond powder mixture can be provided in the form of a
green-state part or mixture comprising diamond powder that is
contained by a binding agent, e.g., in the form of diamond tape or
other formable/conformable diamond mixture product to facilitate
the manufacturing process. In the event that the diamond powder is
provided in the form of such a green-state part it is desirable
that a preheating process take place before HPHT consolidation and
sintering to drive off the binder material. In an example
embodiment, the PCD body resulting from the above-described HPHT
process may have a diamond volume content in the range of from
about 85 to 95 percent. For certain applications, a higher diamond
volume content up to about 98 percent may be desired.
[0066] The diamond powder or green-state part is loaded into a
desired container for placement within a suitable HPHT
consolidation and sintering device. In an example embodiment, where
the source of the solvent metal catalyst material is provided by
infiltration from a substrate, a suitable substrate material is
disposed within the consolidation and sintering device adjacent the
diamond powder mixture. In one or more embodiments, the substrate
is provided in a preformed state. Substrates useful for forming the
PCD body can be selected from the same general types of materials
conventionally used to form substrates for conventional PCD
materials, including carbides, nitrides, carbonitrides, ceramic
materials, metallic materials, cermet materials and mixtures
thereof. A feature of the substrate used for forming the PCD body
is that it includes a solvent metal catalyst capable of melting and
infiltrating into the adjacent volume of diamond powder to
facilitate conventional diamond-to-diamond intercrystalline bonding
during HPHT processing to form/sinter the PCD body. An example
substrate material is cemented tungsten carbide (WC--Co).
[0067] Where the solvent metal catalyst is provided by infiltration
from a substrate, the container including the diamond particles and
the substrate is loaded into the HPHT device and the device is then
activated to subject the container to a desired HPHT condition to
effect consolidation and sintering of the diamond particles. In an
example embodiment, the device is controlled so that the container
is subjected to a HPHT process having a pressure of 5,000 MPa or
more and a temperature of from about 1,350.degree. C. to
1,500.degree. C. for a predetermined period of time. At this
pressure and temperature, the solvent metal catalyst melts and
infiltrates into the diamond particles, thereby sintering the
diamond grains to form conventional PCD.
[0068] While a particular pressure and temperature range for this
HPHT process has been provided, it is to be understood that such
processing conditions can and will vary depending on such factors
as the type and/or amount of solvent metal catalyst used in the
substrate, as well as the type and/or amount of diamond particles
used to form the PCD body or region. After the HPHT sintering
process is completed, the container is removed from the HPHT
device, and the assembly comprising the bonded together PCD body
and substrate is removed from the container. Again, it is to be
understood that the PCD body may be formed without using a
substrate if so desired.
[0069] The PCD body so formed may be of any appropriate thickness.
In particular, the PCD body may have an average thickness (measured
between the upper surface and lower surface) of at least about 1
mm, suitably at least about 1.5 mm, more suitably at least about 2
mm, for example in the range of from about 1.5 mm to about 5 mm,
such as 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 3.25 mm, 3.5 mm or 4
mm.
[0070] PCD bodies useful for forming ultra-hard constructions as
disclosed herein may include those formed at HPHT conditions, such
as those disclosed in US 2010/0294571 A1, which is incorporated
herein by reference. Such PCD bodies can be formed at higher
pressures of approximately 5.4 GPa to 6.3 GPa (cold cell
pressures), which correspond to approximately 6.2 GPa to 7.1 GPa as
temperatures are increased past the cobalt/carbon eutectic line. In
example embodiments, the pressure (at high temperature) is in the
range of approximately 6.2 to 7.2 GPa. In various embodiments, the
cell pressure (at high temperature) may be greater than 6.2 GPa,
for example in the range of from greater than 6.2 GPa to 8 GPa or
from 6.3 GPa to 7.4 GPa, such as 6.25 GPa, 6.35 GPa, 6.4 GPa, 6.45
GPa, 6.5 GPa, 6.6 GPa, or 6.7 GPa.
[0071] FIG. 5B schematically illustrates an example embodiment
polycrystalline diamond construction 30 of the present disclosure
after a second stage of formation, specifically at a stage where
the solvent catalyst material used to initially form/sinter the
diamond body and disposed in the interstitial regions and/or
attached to the surface of the bonded together diamond particles
has been removed from the diamond body 32. At this stage of making
the construction, the PCD body has a material microstructure
resembling region 22 that is illustrated in FIG. 4B, comprising the
diamond matrix phase formed from a plurality of bonded together
diamond particles 24, and interstitial regions 26 that are
substantially free of the specific catalyzing material, e.g.,
cobalt, that was used during the sintering process to initially
form the body of bonded diamond particles and that remains from
that sintering process used to initially form the diamond matrix
phase.
[0072] As used herein, the term "removed" is used to refer to the
reduced presence of the specific material in the body, for example
the reduced presence of the catalyst material that was used to
initially form the diamond body during the HPHT sintering process,
and is understood to mean that a substantial portion of the
material (e.g., catalyst, infiltrant, and/or filler material) no
longer resides within the region of the body. However, it is to be
understood that some small trace amounts of the material may still
remain in the microstructure of the region of the PCD body within
the interstitial regions and/or adhered to the surface of the
diamond particles.
[0073] Additionally, the term "substantially free," as used herein
to refer to the portion of the remaining diamond body after the
specific material has been removed, is understood to mean that
there may still be some trace/residual small amounts of the
specific material remaining within the region of the body as noted
above. In one or more embodiments, the body may be treated such
that more than 98 percent by weight (% w), based on the total
weight of the treated region, has had the material removed from the
interstitial regions within the treated region, in particular at
least 99% w, more in particular at least 99.5% w, same basis, may
have had the material removed from the interstitial regions within
the treated region. At most 2 percent by weight (% w), based on the
total weight of the region of the PCD body, for example at most
1.5% w, 1% w, or 0.5% w, same basis, may remain.
[0074] For example, trace amounts of catalyst material may remain
within the treated PCD body due to the catalyst material being
trapped in the regions of diamond regrowth (diamond-to-diamond
bonding) and is not necessarily removable by treatment methods such
as chemical leaching. The quantity of the specific catalyst
material used to form the diamond body remaining in the material
microstructure after the diamond body has been subjected to
treatment to remove the same can and will vary on such factors as
the efficiency of the removal process, and the size and density of
the diamond matrix material.
[0075] In an example embodiment, the catalyst material used to form
the PCD body may be removed therefrom by a suitable process, such
as by chemical treatment such as by acid leaching or aqua regia
bath, electrochemically such as by electrolytic process, by liquid
metal solubility technique, or by combinations thereof. In one or
more embodiments, the catalyst material is removed by an acid
leaching technique, such as that disclosed for example in U.S. Pat.
No. 4,224,380, which is incorporated herein by reference.
[0076] Accelerating techniques for removing the catalyst material
may also be used, and may be used in conjunction with the leaching
techniques noted above as well as with other conventional leaching
processing. Such accelerating techniques include elevated
pressures, elevated temperatures and/or ultrasonic energy, and may
be useful to decrease the amount of treatment time associated with
achieving the same level of catalyst removal, thereby improving
manufacturing efficiency.
[0077] In one embodiment, the leaching process may be accelerated
by conducting the same under conditions of elevated pressure that
may be greater than about 5 bar and that may range from about 10 to
50 bar in other embodiments. Such elevated pressure conditions may
be achieved by conducting the leaching process in a pressure vessel
or the like. It is to be understood that the exact pressure
condition can and will vary on such factors as the leaching agent
that is used as well as the materials and sintering characteristics
of the diamond body.
[0078] In addition to elevated pressure, elevated temperatures may
also be used for the purpose of accelerating the leaching process.
Suitable temperature levels may be in the range of from about 90 to
350.degree. C. in one embodiment, and up to 175 to 225.degree. C.
in another embodiment. In one or more embodiments, elevated
temperature levels may range up to 300.degree. C. It is to be
understood that the exact temperature condition can and will vary
on such factors as the leaching agent that is used as well as the
materials and sintering characteristics of the diamond body. It is
to be understood that the accelerating technique may include
elevated pressure in conjunction with elevated temperature, which
would involve the use of a pressure assembly capable of producing a
desired elevated temperature, e.g., by microwave heating or the
like. For example, a microwave-transparent pressure vessel may be
used to implement the accelerated leaching process. The
accelerating technique may include elevated temperature or elevated
pressure, i.e., one or the other and not a combination of the
two.
[0079] Ultrasonic energy may be used as an accelerating technique
that involves providing vibratory energy operating at frequencies
beyond audible sound, e.g., at frequencies of about 18,000 cycles
per second and greater. A converter or piezoelectronic transducer
may be used to form a desired ultrasonic stack for this purpose,
wherein the piezoelectric crystals may be used to convert
electrical charges to desired acoustic energy, i.e., ultrasonic
energy. Boosters may be used to modify the amplitude of the
mechanical vibration, and a sontotrode or horn may be used to apply
the vibration energy. The use of ultrasonic energy may produce an
80 to 90 percent increase in leaching depth as a function of time
as compared to leaching without using ultrasonic energy, thereby
providing a desired decrease in leaching time and an improvement in
manufacturing efficiency.
[0080] Referring again to FIG. 5B, at this stage of the process any
substrate 34 that was used as a source of the catalyst material may
be removed from the diamond body 32, and/or may fall away from the
diamond body during the process of catalyst material removal. In an
example embodiment, it may be desired to remove the substrate from
the diamond body before treatment to facilitate the catalyst
removal process, e.g., so that all surfaces of the diamond body may
be exposed for the purpose of catalyst material removal. If the
source of the catalyst material was provided by mixing with or
otherwise providing with the precursor diamond powder, then the
polycrystalline construction 30 at this stage of manufacturing will
not contain a substrate, i.e., it will consist of a diamond body
32.
[0081] FIG. 5C schematically illustrates an example embodiment
polycrystalline construction 30 prepared in accordance with the
present disclosure after a third stage of formation. Specifically,
at a stage where the catalyst material used to initially form the
diamond body has been removed therefrom and has been replaced with
a desired infiltrant material 38 and filler material 36. As noted
above, the infiltrant material may be selected from the group of
materials including metals, ceramics, cermets and combinations
thereof. In an example embodiment, the infiltrant material is a
metal, a mixture of metal or an alloy of metal. In one or more
embodiments, the infiltrant material may be a metal or metal alloy
selected from Group VIII of the Periodic table, such as cobalt,
nickel, iron, combinations and alloys thereof. It is to be
understood that the choice of material or materials used as the
infiltrant material can and will vary depending on such factors
including but not limited to the end-use application, and the type
and density of the diamond grains used to form the polycrystalline
diamond matrix first phase, and the mechanical properties and/or
thermal characteristics desired for the polycrystalline diamond
construction.
[0082] Referring back to FIG. 4B, once the catalyst material used
to initially form the diamond body is removed from the diamond
body, the remaining microstructure comprises a polycrystalline
matrix phase with a plurality of interstitial voids 26 forming what
is essentially a porous material microstructure. This porous
microstructure not only lacks mechanical strength, but also lacks a
material constituent that is capable of forming a strong attachment
bond with a substrate, e.g., in the event that the polycrystalline
diamond construction needs to be in the form of a compact
comprising such a substrate to facilitate attachment to an end-use
device.
[0083] A population of the voids or pores in the polycrystalline
diamond body may be filled with the infiltrant material using a
number of different techniques. Only a portion of the voids in the
diamond body may be filled with the infiltrant material. In one or
more embodiments, the infiltrant material may be introduced into
the diamond body by liquid-phase sintering under HPHT conditions
(infiltration process or re-bonding process). In such embodiments,
the infiltrant material may be provided in the form of a sintered
part or a green-state part that contains the infiltrant material
and that is positioned adjacent one or more surfaces of the diamond
body. The assembly may be placed into a container that is subjected
to HPHT conditions sufficient to melt the infiltrant material
within the sintered part or green-state part and cause it to
infiltrate into the diamond body. In one or more embodiments, the
source of the infiltrant material may be a substrate that will be
used to form a compact from the polycrystalline diamond
construction by attachment to the diamond body during the HPHT
re-bonding process.
[0084] Rather than using a pre-formed substrate as a source of the
infiltrant material, the diamond body may have a desired powder
volume that is positioned adjacent one or more surfaces of the
diamond body to provide the infiltrant material. In an example
embodiment, the desired powder is a metal material containing the
infiltrant material. In an example embodiment, the desired powder
is formed from one or more materials that may be sintered to
provide an element that is attached to the diamond body and that
has desired properties to facilitate use of the resulting sintered
polycrystalline diamond construction in a cutting and/or wear
application, for example the powder mixture may comprise a WC--Co
material. When subjected to HPHT conditions, the cobalt in such
powder mixture melts and infiltrates into the diamond body. Instead
of powder, the infiltrant material can be provided adjacent a
surface of the diamond body in the form of a foil or disc or the
like by chemical plating operations, by electroplating operations
or the like, where the desired infiltrant material is deposited on
the diamond body surface.
[0085] The term "filled," as used herein to refer to the presence
of the infiltrant material and/or filler material in the voids or
pores of the diamond body that resulted from removing the catalyst
material used to form the diamond body therefrom, is understood to
mean that a substantial volume of such voids or pores contain the
infiltrant material and/or filler material. It is understood that a
population of the voids or pores of the diamond body within a
particular region may remain substantially empty or partially
filled due to non-uniform pore size, temperature gradients which
may be present in the press cell or the composition of the
substrate.
[0086] Another population of the voids or pores in the
polycrystalline diamond body may be filled with the filler material
using one or more of the techniques discussed above for introducing
the infiltrant material into the PCD body. Only a portion of the
voids in the diamond body may be filled with the filler material.
In one or more embodiments, the filler material may be introduced
into the diamond body by liquid-phase sintering under HPHT
conditions (infiltration process or re-bonding process). In an
example embodiment the filler material may be provided in the form
of a pre-formed body, such as a ring, foil, disc, substrate and the
like, or in the form of powder, by spray coating or by other
deposition method capable of delivering the filler material to a
desired surface of the diamond body. In an example embodiment,
where the filler material is provided in the form of a pre-formed
body, such body may be positioned adjacent one or more surfaces of
the diamond body (e.g., working surfaces) after the metal catalyst
material used to initially form the same has been removed. The
amount of filler material introduced into the PCD body may be
controlled by adjusting the size and shape of the pre-formed
body.
[0087] The filler material may be introduced into the PCD body by
placing a powder material containing the filler material adjacent
one or more surfaces of the diamond body (e.g., working surfaces)
after the metal catalyst material used to initially form the same
has been removed. The amount of filler material introduced into the
PCD body may be controlled by adjusting the quantity of powder
material placed adjacent the PCD body.
[0088] The filler material may be introduced into the PCD body by a
pressure technique where the filler material may be provided in the
form of a slurry or the like comprising the desired filler material
and a carrier, e.g., such as a polymer or organic carrier. The
slurry may then be exposed to the diamond body (e.g., working
surfaces) at high pressure to cause the slurry to enter the diamond
body and cause the filler material to fill the voids therein. The
PCD body may then be subjected to elevated temperature for the
purpose of removing the carrier therefrom, thereby leaving the
filler material disposed within the interstitial regions. The
amount of filler material introduced into the PCD body may be
controlled by adjusting the quantity of slurry material placed
adjacent the PCD body.
[0089] In one or more embodiments, the filler material has a much
lower melting temperature than the infiltrant material, for example
the melting temperature of the filler material may be at most
700.degree. C., at most 600.degree. C., at most 400.degree. C., at
most 350.degree. C., or at most 300.degree. C. In an example
embodiment, the filler material has a melting temperature that is
less than that of the infiltrant material, at atmospheric
conditions, for example by at least about 400.degree. C.,
preferably by at least about 1,000.degree. C., and more preferably
by at least about 1,200.degree. C.
[0090] In one or more embodiments, the filler material may be
introduced into the PCD body prior to introducing the infiltrant
material since the introduction of the filler material may take
place at a temperature significantly below the thermal degradation
temperature of the PCD body (filling process). The conditions
during such a filling process may include pressures of at least at
least 50 kbar, and at temperature of at least 150.degree. C.
[0091] The filler material may be introduced into the PCD body
during the same process utilized to infiltrate the PCD body with
the infiltrant material (infiltrating process or re-bonding
process). In this embodiment, the assembly includes the filler
material positioned adjacent one or more surfaces of the PCD body
(e.g., working surfaces).
[0092] The assembly containing the filler material (whether
contained within the pores of the PCD body or adjacent a surface of
the PCD body) and the infiltrant material is subjected to HPHT
conditions sufficient to cause the infiltrant (e.g., cobalt from
the substrate) to melt, infiltrate into, and fill a population of
the voids or pores in the polycrystalline diamond matrix not
already filled by the filler material.
[0093] A substrate used as a source for the infiltrant material may
have a material make up and/or performance properties that are
different from that of a substrate used to provide the catalyst
material for the initial sintering of the diamond body. For
example, the substrate selected for sintering the diamond body may
comprise a material make up that facilitates diamond bonding, but
that may have poor erosion resistance and as a result not be well
suited for an end-use application in a drill bit. In this case, the
substrate selected at this stage for providing the source of the
infiltrant material may be selected from materials different from
that of the sintering substrate, e.g., from materials capable of
providing improved down hole properties such as erosion resistance
when attached to a drill bit. Accordingly, it is to be understood
that the substrate material selected as the infiltrant material
source may be different from the substrate material used to
initially sinter the diamond body.
[0094] In an example embodiment, wherein a PCD material is treated
to remove the solvent metal catalyst material, e.g., cobalt, used
to initially form the same therefrom, the resulting diamond body is
subjected to a HPHT re-bonding process for a period of
approximately 100 seconds at a temperature sufficient to meet the
melting temperature of the infiltrant material, which is cobalt.
The source of the cobalt infiltrant material is a WC--Co substrate
that is positioned adjacent a desired surface portion of the
diamond body prior to HPHT re-bonding processing. A filler
material, e.g., tin (Sn), in the form of a foil is placed adjacent
the upper surface of the treated PCD body. FIG. 6A illustrates a
partial cross-sectional view (the surrounding can has been omitted
for purposes of clarity) of an assembly prior to the re-bonding
process. Substrate 634 is placed adjacent a lower surface 665 of
the treated PCD body 610, and a pre-formed foil of the filler
material 635 is placed adjacent an upper surface 664 of the treated
PCD body 610.
[0095] The assembly is placed in an HPHT device, and the HPHT
process is controlled to bring the contents to the melting
temperature of cobalt (about 1,350.degree. C., at a pressure of
about 3,400 to 7,000 MPa) to enable the cobalt to infiltrate into
and fill a population of pores or voids in the diamond body
adjacent the substrate, and to enable the filler material to
infiltrate into and fill another population of pores of voids in
the diamond body adjacent the foil.
[0096] Referring to FIG. 1, the HPHT process is controlled to
subject the sintered diamond body to different conditions
identified in FIG. 1 as Regions 1, 2 and 3. Initially, the diamond
body is subjected to a temperature sufficient to melt the filler
material. In an example embodiment, this temperature is less than
about 700.degree. C., and is understood to vary depending on the
particular filler material that is selected. The pressure within
Region 1 may be above or below the Berman/Simon diamond-graphite
equilibrium line, depending on the amount of pressure useful for
causing the melted filler material to enter the diamond body. In an
example embodiment, the filler material is infiltrated into the
diamond body at a pressure of less than about 3 GPa. Thus, the
pressure for Region 1 may be above or below the diamond-graphite
equilibrium line depending on such factors as the interstitial pore
sizes, and the type of filler material that is selected. In an
example, the pressure in Region 1 may be about 1 GPa above the
diamond-graphite equilibrium line, to ensure that the filler
material infiltrates into the diamond body. Thus, within Region 1
of the HPHT process, the filler material melts and is infiltrated
into the diamond body to form a filler region as described above.
In an example embodiment within Region 1, when the filler material
melts and the process is at an appropriate pressure, the filler
material infiltrates and sweeps into the diamond body within a very
short time, e.g., within a fraction of a second. The rate of
infiltration may be controlled depending on how aggressive the heat
ramp is set within Region 1. In such example embodiment, the filler
infiltration into the diamond body stabilizes over a period of from
about 30 to 600 seconds.
[0097] Subsequently, the HPHT process is controlled to progress
from Region 1 to Region 2 by increasing the temperature and
pressure exerted on the diamond body now containing the filler
region. In an example embodiment, the temperature in Region 2 is
increased from about 700.degree. C. to a temperature that is below
the melting point of the infiltrant material, e.g., for cobalt,
less than about 1,350.degree. C. In Region 2, the pressure during
the HPHT process is also increased for the purpose of transitioning
from Region 1 to cause the infiltrant material to be melted and
infiltrate into the diamond body within Region 3.
[0098] In an example embodiment, the pressure in Region 2 may be
above or below (as illustrated in Region 2a) the diamond-graphite
equilibrium line, depending on the particular pressure exerted in
Region 1. In an example embodiment, the pressure in Region 2 is
about 1 GPa above the diamond-graphite equilibrium line to stay
within the diamond stable region during a simultaneous pressure and
temperature ramp and provide some operating window to account for
cell to cell variation. However, when using filler materials that
do not require pressurization into the diamond stable region (above
the diamond-graphite equilibrium line) for infiltration in Region
1, it may be advantageous to simply ramp quickly through at least a
portion of Region 2a below the diamond-graphite equilibrium line on
the way to Region 3 to minimize any extreme transition.
[0099] Within Region 2, the diamond body, comprising the filler
region, is subjected to increasing pressure and temperature as it
approaches Region 3. A feature of the controlled HPHT process and
use of the filler material as disclosed herein, is that the
presence of the so-formed diamond body filler region operates to
keep the diamond body in an isostatic condition within in the
diamond stable region as the pressure is increased (in Regions 2
and 3), thereby minimizing the possibility of the diamond bonds
being broken and/or the diamond structure being damaged with
increasing pressure.
[0100] As the HPHT process is continued, it reaches Region 3
wherein the temperature is increased to an amount sufficient to
melt the infiltrant material. The pressure in Region 3 is
controlled to be at or above the Berman/Simon diamond-graphite
equilibrium line to keep the diamond body in the diamond stable
region or state. In Region 3, the melted infiltrant material
infiltrates under pressure into the diamond body forming an
infiltrant region to fill the interstitial regions or pores within
such region. In Region 3, the filler region operates together with
the infiltrant region to keep the entire diamond body in an
isostatic condition within the diamond stable region or state,
thereby minimizing or eliminating the possibility of the diamond
body sustaining structural damage during the HPHT process, which
damage could otherwise well occur due to the presence of a
sufficient amount of unfilled interstitial regions or pores. During
the HPHT re-bonding process, the substrate containing the
infiltrant material, e.g., cobalt, is attached to the diamond body
to thereby form a polycrystalline diamond compact construction. The
cobalt from the substrate is the sole source of infiltrant
material.
[0101] In an example embodiment, it is desired that the diamond
body comprises a filler region and an infiltrant region that
together operate to reduce the population of unfilled interstitial
regions within the diamond body during HPHT conditions when in
Region 3 to less than about 2 percent to maintain the diamond body
in a desired diamond-stable state and protect it against undesired
damage to the diamond structure. In an example embodiment, the
population of unfilled interstitial regions within the diamond body
during HPHT processing in Region 3 may be from about 0 to 2
percent, preferably be from about 0 to 1 percent, and most
preferably be 0, or 100 percent of the interstitial regions within
the diamond body are filled (with either the filler material and/or
the infiltrant material) when the diamond body is subjected to the
HPHT processing conditions of Region 3.
[0102] FIG. 6B illustrates a cross-sectional view of a re-bonded
PCD compact construction after infiltration of the infiltrant and
filler materials. The infiltrated PCD body 611 contains a filler
region 633 and infiltrated region 622. The infiltrated region 622
is located adjacent the substrate, extending a depth into the body
from the substrate, and the filler region 633 extends a depth into
the body from a surface opposite the substrate. The major portion
of the filler region 633 has interstitial regions/pores filled with
filler material consisting of tin. The major portion of the
infiltrant region 622 has interstitial regions/pores filled with
infiltrant material. While the interface between the region 633 and
622 has been illustrated as being straight or planar, it is to be
understood that the interface configuration can and will vary
depending on such factors as the thickness, size and/or shape of
the filler material source, and/or the heating balance in the cell.
In some embodiments the interface can be nonplanar in cross
section, e.g., concave or convex.
[0103] While the PCD compact construction illustrated in FIG. 6B
depicts the diamond body 611 bonded directly to the substrate 634,
it is to be understood that PCD constructions as disclosed herein
may include one or more transition layer interposed between the
diamond body and the substrate. In an example embodiment, such
transition layer may be used to provide a transition in one or more
properties between the diamond body and substrate. In an example
embodiment, the transition layer may be used to provide a
transition in the thermal expansion characteristics between the
diamond body and the substrate, wherein such transition layer may
have a diamond content that is less than that of the diamond body
and preferably within between about 80 to 95 wt %.
[0104] In an example embodiment, subsequent to the HPHT re-bonding
process, the PCD construction illustrated in FIG. 6B is
subsequently treated to remove the filler material therefrom. If
desired, all or a portion of the infiltrant material can also be
removed during the same or different treatment. In an example
embodiment, the filler material is removed from the filler region,
and infiltrant material is leached from a portion of the infiltrant
region to thereby form a thermally stable region adjacent: 1) the
entire upper surface; 2) the entire cutting edge; and 3) a portion
of the length of the side surface of the PCD body (including the
entire circumferential distance of the side surface).
[0105] As illustrated in FIG. 6C, a cross-sectional view of the PCD
compact shows the thermally stable region 644 (that is
substantially free of the filler and infiltrant materials) as
extending a depth from the top and side surfaces, and the remaining
infiltrated region 655 extending to the substrate 634. The
particular embodiment illustrated in FIG. 6C shows thermal region
having a depth, as measured from the diamond body top surface, that
is greater near the circumferential edge than near the middle, the
depth decreases moving radially inwardly from the side surfaces
towards the center. This is understood as being but one embodiment
illustrating a configuration of the thermally stable region and
that configurations other than that disclosed and illustrated are
intended to be within the scope of the PCD constructions as
disclosed herein.
[0106] It is advantageous to utilize a low-melting temperature
filler material as described herein because such material readily
infiltrates and sweeps through and into the pores of the treated
PCD body at temperatures and pressures, i.e., during an HPHT
process, that are much lower than those necessary for introducing
the infiltrant into the PCD body. Thus, upon subsequent
infiltration of the infiltrant, which occurs at higher temperatures
and pressures during the HPHT process, the interstitial regions or
pores of the treated PCD body are sufficiently filled with either
the filler material or the infiltrant to ensure that the treated
PCD body remain in the diamond stable region, i.e., above the
Berman/Simon diamond-graphite equilibrium line, during infiltration
of the infiltrant. This operates to protect and prevent regions of
the PCD body from being damaged or otherwise converted to from
diamond to graphite, essentially providing a PDC body capable of
maintaining an isostatic condition during HPHT processing to resist
structural failures otherwise known to occur with conventional PCD
bodies subjected to conventional HPHT processes.
[0107] Additionally, the filler materials selected are those that
can more easily migrate and infiltrate into the small pores of the
treated PCD body then conventional infiltrants, thereby permitting
a deeper level of infiltration into the PCD body than otherwise
possible using conventional infiltrants. Further, such filler
materials can also be more easily removed from the small pores of
the re-infiltrated PCD body, thereby allowing for the creation of a
deeper thermally stable region within the PCD body once removed,
than practically permissible using conventional infiltrants
materials.
[0108] Techniques useful for removing infiltrant or filler material
from the diamond body include the same ones described above for
removing the catalyst material used to initially form the diamond
body, e.g., such as by acid leaching or the like. In an example
embodiment, it is desired that the process of removing the filler
material and optionally the infiltrant material be controlled so
that the material be removed from a targeted region of the diamond
body extending a determined depth from one or more diamond body
surfaces. These surfaces may include working and/or nonworking
surfaces of the diamond body.
[0109] In one or more embodiments, the filler material and
optionally the infiltrant material may be removed from the diamond
body to any suitable depth. In one or more embodiments, the filler
material and optionally the infiltrant material may be removed from
the diamond body to a depth of at most about 2 mm from the desired
surface or surfaces. In one or more embodiments, the filler
material and optionally the infiltrant material may be removed from
the diamond body to a depth of at least about 0.01 mm from the
desired surface or surfaces. For example, the filler material and
optionally the infiltrant material may be removed from the diamond
body to a depth in the range of from about 0.01 mm to about 2 mm
from the desired surface or surfaces, in particular from about 0.05
mm to about 1.5 mm or from about 0.1 mm to about 1 mm, such as 0.75
mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5
mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9
mm or 0.95 mm. Suitably, a depth of at least about 0.3 mm may be
used in one or more embodiments. Ultimately, the specific depth of
the region formed in the diamond body by removing the filler
material and optionally the infiltrant material will vary depending
on the thickness of the PCD body and the particular end-use
application.
[0110] In the embodiments where a portion of the filler material is
removed from the PCD body, the filler material may be any material
capable of filling a population of pores within the treated PCD
body and which has a melting temperature that is lower than the
infiltrant material. Suitably, such filler materials may be
selected from aluminum, gallium, copper, zinc, silver, indium,
thallium, tin, lead, bismuth, alloys and mixtures thereof. In an
example embodiment, the filler material may be selected from
aluminum, gallium, indium, thallium, tin, lead, bismuth, alloys and
mixtures thereof. In an example embodiment, the filler material may
be selected from tin, lead, bismuth, alloys and mixtures thereof.
In an example embodiment, the filler material may be selected from
tin, bismuth, alloys and mixtures thereof. In an example
embodiment, the filler material may consist of tin, bismuth and
alloys thereof. In an example embodiment, the filler material may
consist of tin and alloys thereof. In an example, the filler
material may comprise 95-99% pure tin.
[0111] In the embodiments where the filler material is not removed
from the PCD body, the filler material has a melting temperature
that is lower than the infiltrant material and may be selected from
aluminum, gallium, zinc, indium, thallium, tin, lead, bismuth,
alloys and mixtures thereof. In an example embodiment, the filler
material may be selected from aluminum, gallium, indium, thallium,
tin, lead, bismuth, alloys and mixtures thereof. In an example
embodiment, the filler material may be selected from tin, lead,
bismuth, alloys and mixtures thereof. In an example embodiment, the
filler material may be selected from tin, bismuth, alloys and
mixtures thereof. In an example embodiment, the filler material may
consist of tin, bismuth, and alloys thereof. In an example
embodiment, the filler material may consist of tin and alloys
thereof.
[0112] In an example embodiment, the substrate used to form the
polycrystalline diamond compact construction is formed from a
cermet material, such as that conventionally used to form a PCD
compact. In an example, when the substrate is used as the source of
the infiltrant material, the substrate may be formed from a cermet,
such as a tungsten carbide (WC), further comprising a binder
material that is the infiltrant material used to fill a population
of the pores within the diamond body. Suitable binder materials
include Group VIII metals of the Periodic table or alloys thereof,
and/or Group IB metals of the Periodic table or alloys thereof,
and/or other metallic materials having a melting temperature that
is greater than the filler material.
[0113] In addition to the materials disclosed above, the filler
material can be selected from salts, e.g., metal salts, and
carbonates. Examples include alkali carbonates, alkaline earth
carbonates, fluorides, chlorides, bromides, sulfides and
combinations thereof, which alone or when combined have melting
points below that of the infiltrant material, e.g., cobalt, under
HPHT conditions. Examples include Na.sub.2CO.sub.3,
K.sub.2CO.sub.3, Na.sub.2CO.sub.3+K.sub.2CO.sub.3, MgCO.sub.3,
CaCO.sub.3, LiCl, NaCl, KCl, Na.sub.2CO.sub.3-graphite, NaCl--KCl,
LiCl--NaCl--KCl, and combinations and mixtures thereof. It is to be
understood that the examples provided herein are only
representative of the different types of metal salts, carbonates,
fluorides, chlorides, bromides, sulfides and combinations thereof
that can be used to form filler materials as disclosed herein.
[0114] Although a substrate may be attached to the diamond body
during the infiltrant material introduction, it is also understood
that the substrate may be attached to the diamond body after the
desired infiltrant material has been introduced. In such case, the
infiltrant material may be introduced into the diamond body by a
HPHT process that does not use the substrate material as a source,
and the desired substrate may be attached to the diamond body by a
separate HPHT process or other method, such as by brazing, welding
or the like. The substrate may be attached to the diamond body
before or after the filler material and optionally infiltrant
material have been removed therefrom.
[0115] If desired, an intermediate or transition material may be
interposed between the substrate and the diamond body. The
intermediate material may be formed from those materials that are
capable of forming a suitable attachment bond between both the
diamond body and the substrate. Suitable intermediate materials may
include cermet materials comprising a Group VIII metal such as
WC--Co, WC--Co alloy, or the like. The intermediate material may be
provided as a powder or a partially sintered pre-form. The
intermediate material may additionally include diamond particles
forming a transition layer between the PCD body and the
substrate.
[0116] Although the interface between the diamond body and the
substrate illustrated in FIG. 6C is shown as having a planar
geometry, it is understood that this interface may also have a
nonplanar geometry, e.g., having a convex configuration, a concave
configuration, or having one or more surface features that project
from one or both of the diamond body and substrate. Such a
nonplanar interface may be desired for the purpose of enhancing the
surface area of contact between the attached diamond body and
substrate, and/or for the purpose of enhancing heat transfer
therebetween, and/or for the purpose of reducing the degree of
residual stress imposed on the diamond body.
[0117] Further, polycrystalline diamond constructions of the
present disclosure may comprise a diamond body having properties of
diamond density and/or diamond grain size that may change as a
function of position within the diamond body. For example, the
diamond body may have a diamond density and/or a diamond grain size
that changes in a gradient or step-wise fashion moving away from a
working surface of the diamond body. Further, rather than being
formed as a single mass, the diamond body used in forming
polycrystalline diamond constructions as disclosed herein can be
provided in the form of a composite construction formed from a
number of diamond bodies that have been combined together, wherein
each such body can have the same or different properties such as
diamond grain size, diamond density, or the like
[0118] Polycrystalline diamond constructions the various
embodiments of the present disclosure display marked improvements
in thermal stability and thus service life when compared to
conventional PCD constructions. Polycrystalline diamond
constructions of the present disclosure may be used to form wear
and/or cutting elements in a number of different applications such
as the automotive industry, the oil and gas industry, the aerospace
industry, the nuclear industry, and the transportation industry to
name a few. Polycrystalline diamond constructions of the present
disclosure are well suited for use as wear and/or cutting elements
that are used in the oil and gas industry in such application as on
drill bits used for drilling subterranean formations.
[0119] FIG. 7 illustrates an embodiment of a polycrystalline
diamond compact construction as disclosed here provided in the form
of an insert 70 used in a wear or cutting application in a roller
cone drill bit or percussion or hammer drill bit used for
subterranean drilling. For example, such inserts 70 can be formed
from blanks comprising a substrate 72 formed from one or more of
the substrate materials 73 disclosed above, and a diamond body 74
having a working surface 76 comprising a material microstructure
prepared in accordance with one or more embodiments of the present
disclosure. The blanks are pressed or machined to the desired shape
of a roller cone rock bit insert.
[0120] Although the insert in FIG. 7 is illustrated having a
generally cylindrical configuration with a rounded or radiused
working surface, it is to be understood that inserts formed from
polycrystalline constructions of the present disclosure configured
other than as illustrated and such alternative configurations are
understood to be within the scope of the present disclosure.
[0121] FIG. 8 illustrates a rotary or roller cone drill bit in the
form of a rock bit 78 comprising a number of the wear or cutting
inserts 70 disclosed above and illustrated in FIG. 7. The rock bit
78 comprises a body 80 having three legs 82, and a roller cutter
cone 84 mounted on a lower end of each leg. The inserts 70 may be
fabricated according to the method described above. The inserts 70
are provided in the surfaces of each cutter cone 84 for bearing on
a rock formation being drilled.
[0122] FIG. 9 illustrates the inserts 70 described above as used
with a percussion or hammer bit 86. The hammer bit comprises a
hollow steel body 88 having a threaded pin 90 on an end of the body
for assembling the bit onto a drill string (not shown) for drilling
oil wells and the like. A plurality of the inserts 70 is provided
in the surface of a head 92 of the body 88 for bearing on the
subterranean formation being drilled.
[0123] FIG. 10 illustrates a polycrystalline construction compact
of the present disclosure embodied in the form of a shear cutter 94
used, for example, with a drag bit for drilling subterranean
formations. The shear cutter 94 comprises a diamond body 96,
prepared in accordance with one or more embodiments of the present
disclosure. The body is attached to a cutter substrate 98. The PCD
body 96 includes a working or cutting surface 100.
[0124] Although the shear cutter in FIG. 10 is illustrated having a
generally cylindrical configuration with a flat working surface
that is disposed perpendicular to a longitudinal axis running
through the shear cutter, it is to be understood that shear cutters
formed from polycrystalline diamond constructions of the present
disclosure may be configured other than as illustrated and such
alternative configurations are understood to be within the scope of
the present disclosure.
[0125] FIG. 11 illustrates a drag bit 102 comprising a plurality of
the shear cutters 94 described above and illustrated in FIG. 10.
The shear cutters are each attached to blades 104 that each extend
from a head 106 of the drag bit for cutting against the
subterranean formation being drilled.
[0126] One of ordinary skill in the art should appreciate after
learning the teachings of the present disclosure that various other
tools may use the cutting elements of the present disclosure. Such
tools may include reamers, stabilizers, hole openers, down hole
tool sleeves (which may be welded to a bit).
[0127] Other modifications and variations of polycrystalline
diamond bodies, constructions, compacts, and methods of forming the
same according to the principles of the present disclosure will be
apparent to those skilled in the art. For example in the present
disclosure, embodiments may refer to diamond or polycrystalline
diamond; however, it is intended such embodiments may also include
ultra-hard materials generally. For example, the cutting edge may
be depicted as having a sharp edge between the top surface and side
surface of the PCD body; however, such cutting edge may also be a
beveled cutting edge having a bevel angle from 20 to 80 degrees.
For example, two or more filler materials may be used in forming
the polycrystalline ultra-hard construction of the present
disclosure.
[0128] While polycrystalline ultra-hard constructions and methods
of making the same have has been described with respect to a
limited number of embodiments, those skilled in the art having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the
polycrystalline ultra-hard constructions and methods of making the
same as disclosed herein. Accordingly, the scope of polycrystalline
ultra-hard constructions and methods of making the same as
disclosed herein should be limited only by the attached claims.
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