U.S. patent application number 14/213682 was filed with the patent office on 2014-09-18 for downhole tools including ternary boride-based cermet and methods of making the same.
This patent application is currently assigned to SMITH INTERNATIONAL, INC.. The applicant listed for this patent is SMITH INTERNATIONAL, INC.. Invention is credited to MINGDONG CAI, XIN DENG, ANTHONY GRIFFO, GREGORY T. LOCKWOOD, SIKE XIA.
Application Number | 20140262542 14/213682 |
Document ID | / |
Family ID | 51522467 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140262542 |
Kind Code |
A1 |
CAI; MINGDONG ; et
al. |
September 18, 2014 |
DOWNHOLE TOOLS INCLUDING TERNARY BORIDE-BASED CERMET AND METHODS OF
MAKING THE SAME
Abstract
Downhole tools include a component, at least a portion of which
includes ternary boride cermet. A method of making a downhole tool
including a ternary boride cermet includes obtaining a ternary
boride cermet material and heating the ternary boride cermet
material and a binder to form the downhole tool.
Inventors: |
CAI; MINGDONG; (HOUSTON,
TX) ; LOCKWOOD; GREGORY T.; (PEARLAND, TX) ;
DENG; XIN; (SPRING, TX) ; XIA; SIKE;
(PEARLAND, TX) ; GRIFFO; ANTHONY; (THE WOODLANDS,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SMITH INTERNATIONAL, INC. |
Houston |
TX |
US |
|
|
Assignee: |
SMITH INTERNATIONAL, INC.
Houston
TX
|
Family ID: |
51522467 |
Appl. No.: |
14/213682 |
Filed: |
March 14, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61801484 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
175/428 ; 51/307;
51/309 |
Current CPC
Class: |
E21B 10/46 20130101;
B24D 18/00 20130101; C22C 1/051 20130101; B22F 2003/1051 20130101;
B22F 2003/1054 20130101; B22F 3/1035 20130101; C22C 29/14 20130101;
B22F 2005/001 20130101; B22F 3/105 20130101; B22F 3/14
20130101 |
Class at
Publication: |
175/428 ; 51/307;
51/309 |
International
Class: |
E21B 10/567 20060101
E21B010/567; B24D 18/00 20060101 B24D018/00 |
Claims
1. A downhole tool comprising a component, wherein at least a
portion of the component comprises ternary boride cermet.
2. The downhole tool of claim 1, wherein the component is selected
from the group consisting of cutters, ultra-hard material cutters,
drill bit bodies, nozzles, inserts, reamers, bore-hole enlargement
tools, bits, stabilizers, well-bore departure mill heads, roller
cone bits, and thrust bearings.
3. The downhole tool of claim 1, wherein the ternary boride cermet
is made from at least one metal and at least one boride.
4. The downhole tool of claim 1, wherein the component is an earth
boring drill bit body, at least a portion of which is made from the
infiltration of the ternary boride cermet with a binder.
5. The downhole tool of claim 1, wherein the downhole tool is a
cutting element comprising an ultra hard material cutting layer
attached to a substrate, at least a portion of the substrate
comprising the ternary boride cermet.
6. The downhole tool of claim 1, wherein the component is
substantially free of tungsten.
7. The downhole tool of claim 1, wherein the component further
comprises tungsten carbide.
8. The downhole tool of claim 7, wherein the ternary boride cermet
is present at about 5 wt % to about 100 wt % and the tungsten
carbide is present at most at about 95 wt %.
9. The downhole tool of claim 1, wherein the component comprising
the ternary boride cermet is hardfacing.
10. A method of making a downhole tool comprising a ternary boride
cermet, the method comprising: obtaining a ternary boride cermet
material; and heating the ternary boride cermet material and a
binder to form the downhole tool.
11. The method of claim 10, further comprising: mixing at least one
metal and boron to form a boride metal mixture; and sintering the
boride metal mixture to form the ternary boride cermet
material.
12. The method of claim 11, wherein mixing further comprising
adding a reaction modifier selected from the group consisting of
mono-borides, di-borides, and combinations thereof.
13. The method of claim 11, wherein the at least one metal
comprises nickel and molybdenum, and the boron comprises at least
one selected from the group consisting of molybdenum monoboride,
vanadium boride, chromium monoboride, and combinations thereof.
14. The method of claim 11, wherein the sintering comprises liquid
sintering, hot press sintering, spark plasma sintering, or
microwaving the boride metal mixture.
15. The method of claim 10, further comprising crushing the ternary
boride cermet material to form ternary boride particles, and
wherein heating comprises heating the ternary boride cermet
particles and the binder.
16. The method of claim 15, further comprising: separating the
ternary boride particles; selecting the ternary boride particles
having an average particle size of about 1 .mu.m to about 500
.mu.m; and loading the selected ternary boride particles and the
binder into a mold, wherein heating comprises heating the binder to
infiltrate the ternary boride particles in the mold.
17. The method of claim 10, wherein heating comprises high pressure
high temperature sintering the ternary boride cermet material
adjacent to an ultra-hard material layer to form the downhole
tool.
18. A method of making a downhole tool comprising a ternary boride
matrix, comprising: mixing at least one metal and at least one
boride with an organic binder in a pelletizing pan to form boride
green pellets; sintering the boride green pellets to form a ternary
boride material; and heating the ternary boride material to form
the downhole tool comprising the ternary boride material.
19. The method of claim 18, wherein the at least one boride
comprises at least one metal diboride and at least one metal
monoboride.
20. A method for forming a cutting element comprising: high
pressure high temperature sintering an assembly comprising a
ternary boride cermet and an ultra-hard material to form the
cutting element comprising a ternary boride cermet substrate
attached to an ultra-hard material layer.
21. The method of claim 20, further comprising forming the
substrate by heating ternary boride cermet particles with a binder.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/801,484 filed on Mar. 15, 2013,
entitled "COMPLEX TERNARY BORIDE-BASED CERMET AS ALTERNATIVE TO
TUNGSTEN CARBIDE IN DOWNHOLE TOOL APPLICATIONS" to Cai et al.,
which is incorporated herein by reference in its entirety.
BACKGROUND
[0002] Tungsten carbide has good mechanical properties for drilling
applications, and tungsten carbide-based cemented carbide is
presently the predominant material used in forming downhole tools
including drill bit bodies, drill inserts, reamers, bore-hole
enlargement tools, stabilizers, wellbore departure millheads,
roller cone bits, and thrust bearings for turbines used in
drilling. However, the majority of the world's supply of tungsten
is found outside the United States, rendering a high cost for
tungsten-based products. In addition, cobalt, which is a limited
resource, is used in the manufacturing of tungsten carbide
components, thereby further complicating the use of tungsten
carbide in the manufacture of drilling components.
SUMMARY
[0003] This summary is provided to introduce a selection of
concepts that are further described below in the detailed
description. This summary is not intended to identify key or
essential features of the claimed subject matter, nor is it
intended to be used as an aid in limiting the scope of the claimed
subject matter.
[0004] In some embodiments, a ternary boride cermet is disclosed
for use in the manufacture of drilling components. In some
embodiments, the ternary boride cermet is used in the manufacture
of drilling components, including drill bit bodies, nozzles, drill
inserts, diamond enhanced inserts, gage inserts, substrates for
polycrystalline diamond (PCD) cutters or cutting elements, as well
as hardfacing materials. In some embodiments, ternary boride cermet
is used in making agglomerated pellets which are used in making a
ternary boride matrix used in forming drilling tool and
components.
[0005] In some embodiments, a method of making a ternary boride
matrix includes sintering a mixture of boride particles to form a
ternary boride cermet. The method may further include crushing the
ternary boride cermet to obtain ternary boride cermet particles. To
form a drilling component, the ternary boride cermet (e.g., the
ternary boride particles) may be infiltrated with a binder to form
at least a portion of a body of the component including a ternary
boride matrix.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Embodiments of the present disclosure are described with
reference to the following figures.
[0007] FIG. 1A shows a perspective view of a bit body, according to
one or more embodiments.
[0008] FIG. 1B is a plan view of an ultra-hard material cutter.
[0009] FIG. 2 is a schematic showing ternary boride processing and
formation.
[0010] FIG. 3A is a schematic disclosing methods for preparing a
ternary boride cermet using a vacuum or under protective gas
according to one or more embodiments.
[0011] FIG. 3B is a schematic showing a hot press sintering
apparatus, according to one or more embodiments.
[0012] FIG. 3C is a schematic showing a microwave sintering
apparatus, according to one or more embodiments.
[0013] FIG. 3D is a schematic showing a spark plasma sintering
(SPS) apparatus, according to one or more embodiments
[0014] FIG. 4 is a schematic disclosing methods for forming a
cermet using self-propagating high temperature synthesis (SHS),
according to one or more embodiments.
[0015] FIG. 5 is a schematic disclosing methods for preparing a
ternary boride matrix bit body, according to one or more
embodiments.
[0016] FIG. 6 is a schematic disclosing a pelletizing apparatus for
forming cermet pellets, according to one or more embodiments.
DETAILED DESCRIPTION
[0017] Ternary boride cermets have high strength, high hardness,
good toughness, and excellent corrosion resistance. Ternary boride
cermets have increased sinterability and mechanical properties
compared to binary boride, and the wettability of ternary boride
may be enhanced with a coating, such as a tungsten (W), chromium
(Cr), titanium (Ti), and/or molybdenum (Mo) coating.
[0018] As used herein the term "cermet" refers to a sintered
ceramic metal composition. In some embodiments, a ternary boride
cermet as disclosed herein is used in the manufacturing of downhole
tools and components. Non-limiting examples of these downhole tools
and components include: drill bit bodies, cutting elements such as
polycrystalline ultra-hard material cutters, as for example PCD
cutters or polycrystalline cubic boron nitride (PCBN) cutters,
drill bit bodies including polycrystalline diamond compact (PDC) or
PDC cutter drill bits and PDC "hybrid" drill bits having diamond
impregnated blades, diamond impregnated drill bits, nozzles, drill
inserts, diamond enhanced inserts, gage inserts, reamers, bore-hole
enlargement tools including cutter blocks and bi-center bits,
stabilizers, well-bore departure mill heads, roller cone bits,
thrust bearings used in turbines, as well as hardfacing materials.
The listed tools and components can be manufactured with a ternary
boride cermet following manufacturing methods known in the art. For
these components which are commonly made using a tungsten carbide
cermet, the ternary boride cermet may be used in place of, or
together with, tungsten carbide cermet, thereby reducing the amount
of tungsten. Hard surface coatings may also be formed from ternary
boride cermets.
[0019] A metal-matrix cermet (i.e., composite) used to form an
earth boring drill bit body includes a hard particulate phase and a
ductile metallic phase. The hard particulate phase includes
refractory or ceramic compounds (e.g., nitrides and carbides, such
as tungsten carbide), and the metallic phase may be a binder metal,
such as a metal made of copper and other non-ferrous alloys. In
some embodiments, the presently disclosed ternary boride cermet is
substituted for, or combined with, tungsten or tungsten carbide.
For example, the hard particulate phase may include from about 5 wt
% to about 100 wt % ternary boride cermet with tungsten or tungsten
carbide as a balancer. That is, for example, the hard particulate
phase may include ternary boride cermet at 100 wt % and tungsten
carbide at 0 wt %. In another example, the hard particulate phase
may include ternary boride cermet at 90 wt % and tungsten carbide
at 10 wt %. In another example, the hard particulate phase includes
ternary boride cermet at 85 wt % and tungsten carbide at 15 wt %.
In another example, the hard particulate phase includes ternary
boride cermet at 80 wt % and tungsten carbide at 20 wt %.
[0020] FIG. 1A discloses an earth boring drill bit (5) having a bit
body (7) and cutting elements or cutters (1) which contact the
earth formation during drilling along the edges (9) of their
cutting layers (18), also shown in FIG. 1B. In some embodiments, an
earth boring bit body is made from a ternary boride cermet (e.g.,
at least a portion of an earth boring bit body is made with a
ternary boride cermet).
[0021] Downhole drilling bits may include various "cutters" or
"cutting elements" where such cutting elements include (but are not
limited to): tungsten carbide inserts (TCIs), as well as PDC
inserts, natural or synthetic diamond attached to the drill bit
body; polycrystalline ultra-hard material cutters having a
polycrystalline ultra-hard material cutting layers attached to
substrates that are attached to the bit body, such as PCD cutters
or PCBN cutters; and/or combinations of these cutting elements.
Ultra-hard materials may also be directly attached to the bit body
forming cutting elements. For example, diamond grit hot-pressed
inserts (GHIs), can be bonded to the bit body. In some embodiments,
polycrystalline diamond may be coated on inserts which are
incorporated or attached to the bit body to form diamond enhanced
inserts (DEIs).
[0022] Currently, a drill bit body is formed by infiltrating
tungsten carbide particles with a binder alloy in a mold. The
tungsten carbide is placed in the mold, and the binder alloy may be
placed on top of the tungsten carbide in the mold. During
infiltrating, the binder alloy and tungsten carbide are heated in a
furnace to a flow or infiltration temperature of the binder alloy
so that the binder alloy can bond to the grains of tungsten
carbide. Infiltration occurs when the molten binder alloy flows
through the spaces between the tungsten carbide grains by means of
capillary action. When cooled, the tungsten carbide matrix and the
binder alloy form a hard, durable, strong framework or bit body to
which cutting elements are bonded or otherwise attached. Methods of
forming drill bit bodies using tungsten carbide including drill bit
bodies having PDC inserts, GHIs, and DEIs using tungsten carbide
are described in U.S. Pat. No. 5,593,474, U.S. Pat. No. 8,347,990,
U.S. Patent Publication No. 2004/0244540, U.S. Pat. No. 7,625,521,
WO 97/48874, and U.S. Pat. No. 6,725,953, the entire contents of
all of which are incorporated by reference. Using known
methodologies for forming bit bodies, tungsten carbide cermet may
be substituted with or combined with the presently disclosed
ternary boride cermet.
[0023] For some applications, cutting structures that include
particulate diamond or diamond grit, impregnated in a supporting
matrix are referred to as diamond impregnated. Methods of forming
diamond impregnated cutting structures using a tungsten carbide
cermet are described in U.S. Pat. No. 6,725,953, the entire
contents of which a incorporated herein by reference. In
embodiments, diamond impregnated cutting structures are formed
using a ternary boride cermet in place of, or in addition to, a
tungsten carbide cermet.
[0024] In some embodiments, cutting elements or cutters (1), as
shown in FIG. 1B, are formed having a polycrystalline ultra-hard
material cutting layer (18) bonded to a substrate (12) formed using
ternary boride cermet in lieu of, or in addition to the tungsten
carbide. Examples of cutter or cutting elements having a tungsten
carbide substrate (without ternary boride), as well as examples of
methods of forming the same are provided in U.S. Pat. Nos.
4,604,106, 4,311,490, and 5,351,772, the entire contents of all of
which are incorporated herein by reference. These cutting elements
are formed using a high pressure high temperature (HPHT) sintering
process. A HPHT sintering process includes applying pressure of
about 50 kbar or greater and even 70 kbar or greater at a
temperature of about 1300.degree. C. or greater and often in the
range of about 2000 to 2500.degree. C. Examples of such cutting
elements brazed to a drill bit body (5) after the drill bit body is
formed are shown in FIG. 1. In some embodiments, a ternary boride
is substituted for, or used in addition to tungsten carbide cermet
to form the cutting elements. In other embodiments, a ternary
boride cermet insert is attached to a drill bit body. In some
embodiments, the ternary boride cermet insert is attached to the
drill bit body by brazing, press-fitting, and/or by infiltration.
Methods for brazing, press-fitting (i.e., interference fitting) and
infiltrating an insert to a drill bit body are described
respectively in U.S. Pat. No. 8,360,176, Alan O. Lebeck (1991),
Principles and design of mechanical face seals, Wiley-Interscience,
p. 232, ISBN 978-0-471-51533-3; and U.S. Pat. No. 6,095,265, the
entire contents of all of which are herein incorporated by
reference.
[0025] Methods of forming drill bit bodies using tungsten carbide
are described in U.S. Pat. No. 8,347,990 and U.S. Patent
Publication No. 2004/0244540, the entire contents of both of which
are herein incorporated by reference. In some embodiments, drill
bit bodies may be formed using more than one matrix material. Drill
bit bodies formed of multiple matrix materials are described in
U.S. Pat. No. 8,109,177, the entire contents of which are herein
incorporated by reference. Following disclosed methodologies,
tungsten carbide may be substituted with or combined with the
presently disclosed ternary boride cermet to form these drill bit
bodies from ternary boride cermet or more than one matrix
material.
[0026] In some embodiments, drill nozzles may be made from the
presently disclosed ternary boride cermet in lieu or in addition to
tungsten carbide. Methods for making drill nozzles are described in
U.S. Pat. Nos. 5,927,410 and 8,047,308, the entire contents of both
of which are herein incorporated by reference.
[0027] In some embodiments, a PCD cutting layer may be leached to
remove or decrease the amount of metal catalyst or binder in the
layer forming a thermally stable polycrystalline (TSP) ultra-hard
cutting layer. For example, the ultra-hard cutting layer may be a
TSP diamond material cutting layer. Other processes for forming TSP
bodies include using a non-metal catalyst during the HPHT sintering
process of the diamond particles, and HPHT sintering diamond
particles without the use of a catalyst. TSP materials are
described in U.S. Pat. No. 8,328,891, the contents of which are
fully incorporated herein by reference. In some embodiments, the
TSP material layer is attached to a substrate made with a ternary
boride cermet in lieu of, or in addition to the tungsten carbide
cermet that may be used to form such a substrate. In some
embodiments, the TSP material layer is attached to a substrate by
any suitable method. In some embodiments, the TSP material layer is
attached to the substrate made with ternary boride cermet using
high temperature high pressure (HTHP) processing or hot pressing.
Hot pressing technology is further described herein.
[0028] A ternary boride cermet may also be used in lieu of, or in
addition to, tungsten carbide cermets to form cutting elements
which are mounted on downhole tools such as drag bits, roller cone
bits, reamers, bore-hole enlargement tools including cutter blocks
and bi-center bits, stabilizers, well-bore departure mill heads,
and thrust bearings used in turbines used in drilling. Such cutting
elements include tungsten carbide inserts, GHIs, and DEIs. Examples
of such inserts formed from a tungsten carbide cermet are disclosed
in U.S. Pat. Nos. 6,394,202 and 7,350,599, the contents of both of
which are incorporated herein by reference.
[0029] The presently disclosed ternary boride cermet may also be
used in hardfacing used on drill bits or other tools. Hardfacing
(also referred to as hard surface coating) is the bonding of one or
more metal carbides to the drill bit body using a metal alloy which
provides a layer of hardness and wear resistance to the drill bit
body. In some embodiments, a hard surface coating includes the
presently disclosed ternary boride cermet in combination with or in
lieu of tungsten carbide. Hard surface coating of drill bit bodies
is described in U.S. Pat. No. 4,836,307, the entire contents of
which are herein incorporated by reference. In some embodiments the
hard surface coating including ternary boride cermet is applied by
thermal spray of the ternary boride cermet particles. Thermal spray
techniques are known and described in U.S. Pat. No. 5,535,838, the
entire contents of which are herein incorporated by reference. In
some embodiments, the hard surface coating including ternary boride
cermet is applied by cold spray. Cold spray technology is known and
described in Papyrin et al., Cold Spray Technology, 2007, pages
119-178, the entire contents of which are herein incorporate by
reference. In other embodiments, a hard surface coating including
ternary boride cermet includes applying the coating using an
oxyacetylene torch, tungsten inert gas (TIG) welding, and/or metal
inert gas (MIG) welding.
[0030] FIG. 2 is a schematic outlining the formation of a sintered
ternary boride cermet according to Takagi, 2006, J. of Solid State
Chemistry, 179: 2809-2818, the entire contents of which are herein
incorporated by reference. In some embodiments, a boron source
(e.g. binary boride) (20) is mixed with a metal (22) to form a
mixture (23) which forms ternary boride (24) through a solid state
diffusional boronizing reaction. The boronizing reaction mixture
(25) is then sintered to form a ternary boride cermet including
ternary boride (24) and metal matrix (28). The ternary boride
cermet includes a metal content from about 10 to about 60%. In some
embodiments, the ternary boride cermet includes a metal content
between about 25% and 30%. In some embodiments, a ternary boride is
sintered with carbonyl nickel (Ni). Ternary boride may also be
sintered with a copper, iron, and/or nickel alloy. In some
embodiments, the ternary boride is vanadium (V) and chromium (Cr)
modified Mo.sub.2NiB.sub.2 (nickel-molybdenum complex boride). In
some embodiments, the ternary boride is vanadium (V) and chromium
(Cr) modified Mo.sub.2FeB.sub.2 (iron-molybdenum complex boride).
In some embodiments, when ternary boride is used to form any of the
aforementioned components, the ternary boride particles are
cemented together with iron, nickel, cobalt and/or copper.
[0031] In some embodiments, a method of preparing a ternary boride
cermet includes the methods described above and shown in FIG. 3A.
That is, in some embodiments, a method of preparing a ternary
boride cermet includes mixing borides and metals to form a mixture.
The borides may include vanadium boride (VB), chromium monoboride
(CrB), and/or molybdenum monoboride (MoB). The metals may include
nickel (Ni) and/or molybdenum (Mo). In some embodiments, each of
Ni, Mo, MoB, VB.sub.2, and CrB (23) are mixed in acetone or
ethanol, and processed by ball milling to form a mixture (40)
(block 38). In some embodiments, the mixed metal and boron sources
are in acetone or ethanol (40) and then dried (block 42). The
mixture (40) after drying is then pressed to form a green compact
(45-1) (block 44). The green compact (45-1) is then sintered under
vacuum or protective gas to form a ternary boride cermet (48)
(block 46). The ternary boride cermet (48) may be used in the
manufacture of downhole components (50), as disclosed herein.
[0032] In some embodiments, the boride (20) and metal (22) include
materials having the following purity: 99.85% carbonyl Ni, 99.95%
Mo, MoB having 89.52% Mo and 10.26% B, VB.sub.2 having 68.93% V and
29.84% B, and CrB having 82.99% Cr and 16.54% B. In some
embodiments, the vacuum and heating occurs at a temperature of
about 1200.degree. C. to about 1350.degree. C. In some embodiments,
the vacuum and heating occurs for about 20 to about 30 minutes.
[0033] In another embodiment, the ternary boride cermet is formed
from a mixture (40), which is then sintered using a hot press (70),
as shown schematically in FIG. 3B. In some embodiments, the hot
press (70) includes a graphite punch (62) and graphite mold (60),
surrounding the mixture (40). The graphite punch (62) applies a
load (66) from at least one direction, thereby providing pressure,
and the graphite mold conducts heat to the particle mixture from at
least one heating element (64). In some embodiments, the pressure
from the applied load is in a range of about 4,000 to about 5,000
psi. In some embodiments, the temperature from the heating element
is in a range of about 1,000.degree. C. to about 1,500.degree. C.
As such, a hot press (70) combines pressure and heat for sintering
of the particle mixture (40) to form the ternary boride cermet. The
ternary boride cermet (48) may be used in the manufacture of
downhole components (50), as disclosed herein.
[0034] In another embodiment, the ternary boride cermet is formed
by microwave sintering a green compact (45-1). As shown in FIG. 3C,
the boride green compact (45-1 or 45-2 described later herein) is
placed in a sintering chamber (78) and is then sintered using a
system for microwaving (80) to form a ternary boride cermet that
may be used as a substrate for a polycrystalline ultra-hard
material cutting element or a cutting insert. The microwaves
produced by a microwave generator (74) (e.g., HAMiLab-V3000
manufactured by Synotherm) are controlled and circulated using a
circulation control (76) to sinter the green compact (45-1) in a
sintering chamber (78). Pressure in the sintering chamber is
controlled by a pressure controller (79) and flow rate controller
(81). Microwave sintering can be faster and more energy efficient
than liquid sintering using a conventional vacuum furnace.
Microwave sintering is described in U.S. Pat. Nos. 5,848,348 and
6,004,505, the entire contents of both of which are herein
incorporated by reference.
[0035] In another embodiment, the ternary boride cermet is formed
using spark plasma sintering (SPS) of a mixture (40) using an SPS
apparatus (90). As shown in FIG. 3D, the mixture (40) is surrounded
by a graphite punch (62) and graphite mold (60). The graphite punch
(62) receives an electrical pulse (68) from at least one direction
from an electric pulse generator (92) and applies a load (66) from
at least one direction which imparts pressure. Both the pressure
and the heat generated from the electrical pulse pass through the
graphite punch, to the mixture. The electrical pulse generator (92)
is controlled by an SPS control unit (94). As such, the SPS (90)
sinters the mixture to form a ternary boride cermet that may be
used as a substrate for a polycrystalline ultra-hard material layer
or as a cutting insert. SPS methods are described in U.S. Pat. No.
8,349,040, the entire contents of which are herein incorporated by
reference.
[0036] In another embodiment, ternary boride cermet particles are
made by sintering to near net shape. Near net shape processing is
useful as it can help reduce the overall manufacturing time. Near
net shape processing produces less shrinkage after sintering,
thereby requiring less grinding, which may be expensive and time
consuming. Accordingly, the ternary boride cermet particles are
made directly by forming agglomerates of the boride and metal
mixture and binder alloy of appropriate size which are then
sintered to near net shape. This enables one to determine the shape
as well as the size of the particles.
[0037] In some embodiments, the ternary boride cermet is formed
using self-propagating high temperature synthesis (SHS). SHS is
known and described in U.S. Pat. No. 3,726,643, the entire contents
of which are herein incorporated by reference.
[0038] For SHS, when a compact of the constituent elements is
ignited by furnace heating or by a local heating source (e.g., a
filament) at one end, the highly exothermic reaction propagates
spontaneously and rapidly, converting the reactants into a
refractory product. The reaction temperature can exceed
2500.degree. C. In manufacturing, the SHS technique may have the
advantage of high energy and time efficiency, and in some
instances, high product purity due to the expulsion of volatile
contaminates as a result of extreme high temperatures. The mixed
particles are compacted (also referred to as "reactive compacts"),
and act as a local heat source for joining many materials having
high melting points. Using such reactive compacts, the joining
process can be performed at room temperature without furnaces. The
combustion temperature and propagating rate can also be controlled,
for example, by pre-heating particle reactants to promote the
reaction, and by adding diluents (such as oxide, boride and/or
carbide) to lower the adiabatic combustion temperature and the
propagating rate. SHS may also include conventional particle
processing techniques, such as hot pressing, microwave heating
and/or spark plasma sintering, as described herein.
[0039] Using SHS, it is possible to synthesize binary boride by the
direct reaction of the elements (e.g., Ti+2B, Hf+2B, Mo+B, etc.) or
by the reaction of a metal oxide with boron (e.g., Cr.sub.2O.sub.3,
WO.sub.2, MoO.sub.3 and B). Because of the high adiabatic
temperature (T.sub.ad) (e.g., of about 3000 K) and the volatility
of B.sub.2O.sub.3, some addition of pure metal phase (e.g., Mo) may
be used to form MoB. However, it is also possible to add binary
boride (e.g., MoB, Mo.sub.2B) as a reaction modifier to lower the
T.sub.ad.
[0040] In some embodiments, ternary boride cermet is manufactured
using an SHS technique, as schematically outlined in FIG. 4. In
some embodiments, a cermet including
Mo.sub.2Ni.sub.xB.sub.2(x=0.about.1) is made from a mixture of Mo,
MoO.sub.3, and B with the addition of Ni (99.5%, -325 mesh). This
elemental mixture may be mixed with acetone or ethanol and ball
milling to form a mixture (41a) (block 39a) and then dried (block
42), or dry mixed (e.g., using a V-blender) to form a mixture (41b)
(block 39b). The mixture (41a or 41b) is pressed to form a large
scale green compact (45-2) (block 44). The large scale green packed
compact (45-2) is then heated to 800.degree. C. to 1350.degree. C.
under vacuum or under an inert gas (e.g., a protective gas such as
Ar) to complete the SHS process (block 47). In some embodiments, a
cermet including Mo.sub.2Fe.sub.xB.sub.2(x=0.about.1) is made from
a mixture of Mo, MoO.sub.3, B with the addition of Fe (99.5%,
-200mesh), green compacted and heated to 1000.degree. C. to
1350.degree. C. In both cases, SPS (FIG. 3D) and/or hot press (FIG.
3B) can also be included in the SHS process. In some embodiments, a
small addition of V and Cr can also be used to modulate the ternary
boride microstructure and, therefore enhance the mechanical
properties. In some embodiments, a small addition of binary boride
(e.g., MoB and/or Mo.sub.2B) as diluents may be used to control the
reaction temperature and propagating rate. In some cases, an
addition of carbon (<0.5 wt %) may help to reduce oxidization
during high temperature synthesis.
[0041] In some embodiments, a method of manufacturing a ternary
boride bit body or other cutting structures, as shown in FIG. 5,
includes mechanically crushing a ternary boride cermet (48) in
accordance with any one of the embodiments described and shown
herein. The crushing of the sintered ternary boride cermet (48)
forms crushed ternary boride cermet particles (53) (block 52). The
crushed cermet particles (53) are then separated (54) to collect
different sized ternary boride cermet particles (55) (block 54). In
some embodiments, the cermet particles are separated to obtain
particles having an average particle size in the range of about 1
.mu.m to about 500 .mu.m. In some embodiments, the selected
particles have an average particle size in the range of about 45
.mu.m to about 160 .mu.m. The wettability of the selected ternary
boride cermet particles (55) may be increased by applying a metal
layer or coating by vapor deposition (block 56) or any other
suitable coating method. The vapor deposition may be by chemical
vapor deposition (CVD) or physical vapor deposition (PVD). The
ternary boride cermet particles with or without a coating are then
loaded into a bit mold and subject to vibration (block 57). The
loaded mold is then infiltrated under pressure or pressure-less
conditions (block 58). In one embodiment, the separated, selected,
and loaded ternary boride cermet particles are infiltrated with
Cu-based, Fe-based, and/or Al-based alloys at about 850.degree. C.
to about 1250.degree. C. to form a bit body (58) including ternary
boride cermet.
[0042] In some embodiments, the crushed ternary boride cermet
particles are placed in a mold and infiltrated with a copper alloy
to form a drill bit body, insert, and/or a plurality of blades. In
some embodiments, the ternary boride cermet particles (55) are
mixed with a metal (e.g., iron, nickel and/or copper alloys), and
the metal and ternary boride cermet mixture is added to a drill bit
mold forming at least a plurality of blades on a bit body, and is
infiltrated with a copper alloy to form a drill bit body having a
plurality of blades. In some embodiments, the plurality of blades
include at least one cutting element attached thereto, the cutting
element made from ternary boride cermet. In some embodiments, at
least a portion of the drill bit including the plurality of blades
may be made from ternary boride cermet in the absence of tungsten
carbide. That is, a portion of the drill bit is substantially free
of tungsten carbide, where substantially free of tungsten carbide
is defined as including no more than 5 wt % tungsten carbide. In
other embodiments, at least a portion of the drill bit including
the plurality of blades is made from a mixture of ternary boride
cermet and tungsten carbide cermet, as described herein. In some
embodiments, the cutting element including the substrate and/or the
insert (optionally attached to the drill bit blades) is made from
ternary boride cermet and is substantially free of tungsten
carbide. In other embodiments, the cutting element (optionally
attached to the drill bit blades) is made from a mixture of ternary
boride cermet and tungsten carbide cermet, as described herein.
[0043] In another embodiment, ternary boride pellets can be
manufactured by sintering pre-mixed boride green pellets (100)
using the methods discussed herein (e.g. FIGS. 3B-3D). As shown in
FIG. 6, boride green pellets are formed by transforming the mixture
(40) (FIG. 3A) into shaped green pellets by rotating the mixture
with an organic binder (e.g., wax or polymer) in a pelletizing pan
(105). The possible shapes of the pellets is controlled by the
technique used in conjunction with the pelletizing pan, including
but not limited to the tilt angle of the pan, the rotational speed
of the pan, and the amount of wax or polymer added. As such,
non-limiting examples of shapes of the pellets include spherical,
semi-spherical, elliptical, and angular. This process is also
referred to as disc type pelletizing. The boride green pellets
(100) may be sintered thereafter for use in various downhole tool
components and applications, e.g., hardfacing and in a drill bit
body. In some embodiments, the green pellets may be sintered with a
binder to form at least a portion of downhole cutting tool. In
other embodiments, the boride green pellets may be sintered to form
sintered ternary boride pellets which may then be used to form at
least a portion of a downhole cutting tool. In other embodiment,
the sintered ternary boride pellets are crushed to form ternary
boride particles which are used to form cutting tools as described
herein.
[0044] Although a few embodiments have been described in detail
above, those skilled in the art will readily appreciate that many
modifications are possible in the embodiments without materially
departing from this disclosure. All such modifications are intended
to be included within the scope of this disclosure. It is the
express intention of the applicant not to invoke 35 U.S.C.
.sctn.112, paragraph 6 for any limitations of any of the claims
herein, except for those in which the claim expressly uses the
words `means for` together with an associated function.
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