CORE DRILL BIT BINDER MATERIALS

Abstract

Ag-free or low-Ag binder alloys are provided that can be used as binders for abrasive materials such as core drill bits. The alloys comprise, or consist of, Cu, Sn and Ni, with Cu preferably the plurality or majority component. Methods of manufacturing abrasive materials comprising the binder alloys, such as infiltration processes, are also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63/257,725 filed Oct. 20, 2021, the disclosure of which is expressly incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The subject matter relates to materials that can be used as binders for abrasive materials such as core drill bits; to articles, such as core drill bits, comprising the binder material; and to methods, such as infiltration, for manufacturing such articles.

BACKGROUND OF THE INVENTION

Core drill bits are manufactured via an infiltration process whereby a mold is packed with a matrix powder and infiltrated with a molten binder material. The matrix typically consists of or comprises a particulate material such as tungsten although may comprise other materials such as silicon carbide. The binder material is typically a copper based material containing silver. Silver-containing binder materials are prevalent in core drill bits, despite the high cost of silver, due to the good free cutting behavior of silver containing binders. There are known copper based binder materials used by the drill bit industry (such as oil drilling bits) more generally, Cu53 (Cu 53, Mn 25, Ni 15, Zn 7) which would be desirable from a cost perspective. However, these Ag-free alloys have thus far demonstrated poor free cutting behavior when used in the core drill bit application.

Other copper-based infiltrants similar to Cu53 include

Cu: 86, Ni: 2, Mg: 12;

Cu: 80 Sn: 20;

Cu: 79.2, Ni: 10, Mg: 5; Sn: 5.5. Si: 0.3;

Cu: 70, Ni: 10, Mg: 20; and

Cu: 60 Zn: 40.

The above binder materials are not effective replacements for the more expensive Ag-containing binders due to poor properties, such as poor free cutting behavior.

The most common core drill bit binder materials include Ag 40 (Cu 60; Ag 40) Ag 30A (Cu: 70, Ag: 30) Ag 30B (Cu 60; Ni: 10 Ag; 30), Ag 20 (Cu 76; Ag 20; Ni 4) and Ag 10 (Cu: 90; Ag: 10) (with all alloying compositions provided in wt. %).

EP2771533B1 describes Ag-free binder alloys having Zn content of 25% or more in copper and/or nickel binder alloys. Use of high Zn levels can be problematic since Zn can easily vaporize in a variety of industrial manufacturing operations, which can lead to health concerns and/or consistency issues in product performance.

Despite the high cost of Ag, because Ag-free alloys exhibit decreased performance and/or have health/manufacturing issues, alloys comprising a significant amount of Ag remain binder materials of choice for abrasive applications such as core drill bits.

There is a need for binder materials comprising decreased amounts of Ag, preferably Ag-free, that exhibit good properties in abrasive applications such as core drill bits. There is a need for high quality components for abrasive applications comprising binder materials with low or no Ag content and/or low or no Zn content.

SUMMARY OF THE INVENTION

An alloy is provided comprising 1-33 wt % Ni, 12-38 wt % Sn, and Cu, wherein Cu is the plurality or majority component. Preferably, the binder alloy comprises 10 wt % Ag or less, or 5 wt % Ag or less. Preferably, the binder alloy comprises 20 wt % Zn or less, or 5 wt % Zn or less.

Preferably, the binder alloy satisfies at least one of the following formulas:

17-33 wt % Ni,12-24 wt % Sn,  (A1)

4-8 wt % Ni,15-29 wt % Sn,  (A2)

7-13 wt % Ni,20-28 wt % Sn,  (A3)

1-3 wt % Ni,14-27 wt % Sn, or  (A4)

6-12 wt % Ni,11-21 wt % Sn.  (A5)

Preferably, the binder alloy comprises a balance of Cu.

The mushy zone is defined as the liquidus temperature minus the solidus temperature. Preferably, the binder alloy has a mushy zone of 150K or less. Preferably, the binder alloy comprises a matrix microstructure comprising a CuSn gamma phase, wherein the CuSn gamma phase comprises 0.1% to 70% of the matrix microstructure

An abrasive article is provided comprising an abrasive material in a matrix comprising the binder alloy. The abrasive article preferably comprises a core drill bit.

A core drill bit is provided comprising an abrasive material in a matrix comprising the binder alloy. The core drill bit preferably has a Vickers hardness HV_0.3 of 250 or greater. The core drill bit preferably has a transverse rupture strength (TRS) of 30 ksi (or 200 MPa) or greater. As is known in the art, 1 ksi (kilopound/in²) is about 6.89 MPa.

A process of manufacturing a composite article, preferably an abrasive article, is provided, the process preferably comprising an infiltration process. The process of manufacturing preferably comprises:

• • placing an abrasive particulate material into a mold;
  • melting a binder alloy (e.g., as described herein) to obtain a molten binder;
  • allowing the molten binder to enter the mold and contact the particulate material to obtain a coated particulate material; and
  • cooling the coated particulate material to obtain the abrasive article.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a CALPHAD diagram showing the mol fraction of various phases of Cu 57 Ni 25 Sn 18 (wt %) as a function of temperature. Ni is not separately shown since it is dissolved in the Cu FCC and CuSn gamma phase.

FIG. 2 is an SEM photomicrograph of a slice of Cu 57 Ni 25 Sn 18 (wt %) that has been melted and solidified.

FIG. 3 is a CALPHAD diagram showing the mol fraction of various phases of Cu 61 Ni 10 Sn 29 (wt %) as a function of temperature. Ni is not separately shown since it is dissolved in the Cu FCC and CuSn gamma phase.

FIG. 4 is an SEM photomicrograph of a slice of Cu 61 Ni 10 Sn 29 (wt %) that has been melted and solidified.

FIG. 5 is an SEM photomicrograph of a slice of Cu 57 Ni 25 Sn 18.

FIG. 6 is an SEM photomicrograph of a slice of Cu 61 Ni 10 Sn 29.

DESCRIPTION OF THE INVENTION

The present invention includes binder materials that comprise or consist of Ag-free or low-Ag binder alloys that can be used as binders for abrasive materials such as core drill bits. The alloys comprise, or consist of, Cu, Sn and Ni, with Cu preferably the plurality or majority component. The present invention also includes methods of manufacturing abrasive materials comprising the binder alloys, such as infiltration processes.

Binder Material:

A copper-based binder material is provided comprising a binder alloy, the binder alloy comprising copper as the plurality or majority component, and further comprising nickel and tin. The binder alloy preferably comprises 44-84 copper, 1-33 nickel, and 11-38 tin; more preferably 51-81 copper, 1-29 nickel, and 13-34 tin. All amounts are provided in wt %.

Some preferred binder alloys include (with copper the balance):

Ni:17-33,Sn:12-24 more preferably Ni:21-29,Sn:15-21;  A1:

Ni:4-8,Sn:15-29 more preferably Ni:5-7,Sn:18-25;  A2:

Ni:7-13,Sn:20-38 more preferably Ni:8-12,Sn:24-34;  A3:

Ni:1-3,Sn:14-27 more preferably Ni:1-3,Sn:17-24; and  A4:

Ni:6-12,Sn:11-21 more preferably Ni:7-11,Sn:13-19  A5:

It is desirable to limit Ag content as elevated levels of Ag increases the raw material cost of the binder alloy. While it is permissible to include silver, preferred binder alloys comprise less than 10 wt % Ag, preferably less than 5 wt %. Ag, below 1 wt % Ag, below 0.1 wt % Ag, below 0.01 wt % Ag, or 0 wt % Ag. Ranges including two of these values are also preferred. Some preferred ranges include 0-10 wt % Ag, 0-5 wt % Ag, 0-1 wt % Ag, 0-0.1 wt % Ag, 0-0.01 wt % Ag, 0.01-10 wt % Ag, 0.01-5 wt % Ag, 0.01-1 wt % Ag, 0.01-0.1 wt % Ag, 0.1-10 wt % Ag, 0.1-5 wt % Ag, 0.1-1 wt % Ag, 1-10 wt % Ag, and 1-5 wt % Ag.

It is preferable to limit Zn content as Zn can easily vaporize in a variety of industrial manufacturing operations which can lead to health concerns and/or consistency issues in product performance. Preferably Zn content in the binder alloy is below 20 wt %, below 10 wt %, below 1 wt %, below 0.1 wt % or 0 wt % Zn. Ranges including two of these values are also preferred. Some preferred ranges include 0-20 wt % Zn, 0-10 wt % Zn, 0-1 wt %/o Zn, 1-0.1 wt % Zn, 0.1-20 wt % Zn, 0.1-10 wt % Zn, 0.1-1 wt % Zn, 1-20 wt % Zn, and 1-10 wt % Zn.

Preferably, the binder alloy comprises, or consists of, Cu Ni and Sn. All such binder alloys permit the presence of trace impurities. Trace impurities can include, e.g., O, S, P, Bi, Si, Al, and combinations of one or more thereof. Trace impurities are preferably present in amounts of less than or equal to 1.0 wt %, 0.1 wt %, or 0.05 wt %, individually or collectively (i.e., two or more thereof). Some preferred amounts include 0-1.0 wt %, 0-0.1 wt %, 0-0.05 wt %, 0.05-1.0 wt %, 0.05-0.1 wt %, and 0.1-1.0 wt %, individually or collectively.

Thermodynamics:

The binder alloys disclosed herein can be described by thermodynamic features.

The binder alloys described herein preferably exhibit eutectic transitions, whereby two different solid phases precipitate from the liquid upon cooling. This eutectic transition can create a microstructure useful for free cutting behavior necessary for core drill bit performance.

One phase of the eutectic transition is preferably FCC copper. Another phase of the eutectic transition is preferably CuSn gamma phase. It has been demonstrated via experimental efforts presented below that the CuSn gamma phase fraction present at the solidus temperature in a CALPHAD thermodynamic calculation closely resembles the experimentally measured CuSn gamma phase fraction of an arc melted ingot. Thus, the CuSn gamma phase fraction calculated or determined at the solidus temperature can be used as a parameter for alloy design.

In some embodiments the CuSn gamma phase fraction at solidus is 10 mol % or greater, 20 mol % or greater, or 30 mol % or greater.

It is also desirable for the infiltration binder alloys to have a sufficiently low melting temperature such that they can be sufficiently infiltrated with conventional commercial processes. It is also generally desirable for the mushy zone to be as low as possible which results in a lower degree of compositional variation from the top of the drill bit to the bottom. A smaller mushy zone can be obtained by providing alloys having proportions of components at the eutectic point or near the eutectic point (hypereutectic or hypoeutectic). For precise eutectic compositions, e.g., alloys in which the composition corresponds to the minimum of the eutectic well, the liquidus and solidus merge, such that the mushy zone is OK.

In particular, the eutectic point can be characterized by the composition at which two solids precipitate from the liquid without either solid precipitating first at a higher temperature. A binary (e.g., two elements) eutectic system yields a mushy zone of OK. In multi-element systems it is possible to have two solids start to precipitate at the same temperature from the liquid and to have a non-zero mushy zone (e.g., alloy X3 described below). In such cases the eutectic point corresponds to the minimum possible mushy zone which can be achieved in the alloy system.

It is generally advantageous for the binder alloy to have a small mushy zone. Among other things, a small mushy zone results in more uniform articles of manufacture, e.g., manufacture by an infiltration process. The mushy zone of the binder alloy is preferably 150K or lower, 110K or lower, 100K or lower, or 75K or lower. The mushy zone is generally OK or higher, 10K or higher, or 20K or higher. Some preferred ranges include 0-150K, 0-110K, 0-100K, 0-75K, 10-150K, 10-110K, 10-100K, 10-75K, 20-150K, 20-110K, 20-100K, and 20-75K.

There is no precise upper limit on the liquidus of the binder alloy, though it should preferably be low enough to be amenable to manufacture an article by an infiltration process without damaging the particulate material in the particular application. As a general matter, the liquidus temperature of the binder alloy can be 1300K or lower, 1175K or lower, or 1150K or lower. There is no fixed lower limit on the liquidus of the binder alloy, though as a general matter the liquidus can be 1050K or higher, or 1100K or higher. Some preferred ranges include 1050-1300K, 1050-1175K, 1050-1150K, 1100-1300K, 1100-1175K, and 1100-1150K.

Microstructure:

Binder alloys of the present invention can also be described in terms of their microstructural features. The binder alloys form a eutectic type microstructure comprising a copper matrix and a CuSn gamma phase (in which phases the Ni is dissolved). Specifically, the alloy may be pro-eutectic wherein the copper based matrix forms in advance of the CuSn gamma phase during solidification of the material.

Through alloy control it is possible to adjust the fraction of the CuSn gamma phase and it is desirable to do so dependent on drilling conditions. Currently, such a processes have been done using varied Ag contents with increased Ag leading to increased precipitate phase fraction.

The CuSn gamma phase preferably comprises 0.1% or more, 5% or more, or 20% a or more of the matrix microstructure. The CuSn gamma phase preferably comprises 70% or less, 65% or less, or 60% or less of the matrix microstructure. Some preferred ranges for the CuSn gamma phase include 0.1-70%, 0.1-65%, 0.1-60%, 5-70/o, 5-65%, 5-60%, 20-70%, 20-65%, and 20-60%, of the matrix microstructure. The FCC Cu phase preferably comprises 70% or less, 65% or less, or 60% or less of the matrix microstructure. The FCC Cu phase preferably comprises 0.1% or more, 5% or more, or 20% or more of the matrix microstructure. Some preferred ranges for the FCC Cu phase include 0.1-70%, 0.1-65%, 0.1-60%, 5-70%, 5-65%, 5-60%, 20-70%, 20-65%, and 20-60% of the matrix microstructure. Phase proportions can be measured using image analysis (preferably using image analysis software) of SEM images to measure area fraction of a given phase.

Abrasive Articles:

Abrasive articles according to the present invention include particulate material bound to a metal matrix, the metal matrix comprising, consisting essentially of, or consisting of, a binder alloy as described herein. Abrasive articles preferably include drill bits, including core drill bits.

An advantageous process for manufacturing abrasive articles, such as core drill bits, is by infiltration. The particulate material can comprise any particulate material suitable for use in an abrasive article, e.g., a core drill bit. The particulate material preferably does not undergo melting, and preferably does not undergo sintering, at temperatures used in the manufacturing process, such as infiltration. Some suitable particulate materials include refractory metals (e.g., tungsten, molybdenum, and/or niobium) and/or other materials (e.g., carbides (such as tungsten carbide and/or silicon carbide), graphite and/or diamond).

Performance:

An effective core drill bit binder alloy should infiltrate a mold comprising an abrasive particulate e.g., tungsten powder, at typical industry infiltration temperatures; exhibit good bonding with the tungsten particles to form a strong composite structure; and possess a sufficiently high hardness value.

Methods to quantify the quality of infiltration and bonding in experimental binder alloys include microstructural evaluation, and measurement of the transverse rupture strength of the composite part.

Any temperature suitable for the infiltration process may be used, and can be determined by a person of ordinary skill in the art in view of the materials used, and using the present disclosure as a guide. Without limiting the present disclosure, binding alloys disclosed herein exhibit good infiltration and bonding with tungsten particles at 1200° C. or below, or at 1100° or below. The infiltration process should take place at a temperature above the liquidus of the binding alloy.

In some embodiments, the alloys exhibit good infiltration and bonding with tungsten particles as characterized by a TRS of 40 ksi (or 275 MPa) or greater in a tungsten matrix infiltrated pin. In preferred embodiments, the alloys exhibit good infiltration and bonding with tungsten particles as characterized by a TRS of 75 ksi (or 515 MPa) or greater in a tungsten matrix infiltrated pin. In still preferred embodiments, the alloys exhibit good infiltration and bonding with tungsten particles as characterized by a TRS of 90 ksi (or 620 MPa) or greater in a tungsten matrix infiltrated pin

Depending on drilling conditions, it may be desirable to tailor to hardness of the binder alloy to harder or softer sides of the spectrum. The Cu—Ni—Sn alloy space disclosed here offer a greater degree of hardness tuneability. The Ag20 and Ag40 alloys are similar in hardness at 100 HV Vicker hardness. In contrast, the X1 and X3 alloys have ˜300 HV and the X2, X4 alloys have ˜200 HV.

In some embodiments, the alloys exhibit Vickers hardness in excess of 100 HV. In preferred embodiments, the alloys exhibit Vickers hardness in excess of 200 HV. In preferred embodiments, the alloys exhibit Vickers hardness in excess of 300 HV. Some preferred ranges include 100-300 HV, 100-100 HV, and 200-300 HV.

Abrasive articles comprising abrasive particles in a matrix comprising the binder alloy exhibit good properties such as hardness and strength. Vickers hardness HV_0.3 is preferably greater than or equal to 250, 300, or 350. While there is no preferred upper limit, as a practical matter, Vickers hardness will generally be less than or equal to 450 or 400. The units for Vickers hardness is kgf/mm². Some preferred ranges include 250-450 kgf/mm², 250-400 kgf/mm², 300-450 kgf/mm², 300-400 kgf/mm², 350-450 kgf/mm², and 350-400 kgf/mm².

The above abrasive articles exhibit high transverse rupture strength (TRS), e.g., as measured on infiltrated pins manufactured from the same composition (e.g., abrasive particles and binder alloy). The TRS is preferably greater than or equal to 30 ksi (or 200 MPa), 50 ksi (or 345 MPa), or 75 ksi (or 515 MPa). While there is no preferred upper limit, as a practical matter, TRS will generally be less than or equal to 200 ksi (or 1375 MPa), 150 ksi (or 1030 MPa), or 125 ksi (or 860 MPa). Some preferred TSR ranges include 30-200 ksi, 30-150 ksi, 30-124 ksi, 50-200 ksi, 50-150 ksi, 50-124 ksi, 75-200 ksi, 75-150 ksi, 75-124 ksi, 200-1375 MPa, 200-1030 MPa, 200-860 MPa, 345-1375 MPa, 345-1030 MPa, 345-860 MPa, 515-1375 MPa, 515-1030 MPa, and 515-860 MPa.

Examples

Four Example binding alloys were prepared, having the following nominal compositions (in wt %):

Cu57Ni25Sn18  X1:

Cu72Ni6Sn22  X2:

Cu61Ni10Sn29  X3:

Cu77Ni2Sn21  X4:

Two Comparative Examples were also prepared, Ag20 (Cu 76 Ag 20 Ni 4) and Ag40 (Cu 60 Ag40).

The four experimental alloys (X1, X2, X3, and X4) and two Comparative Examples were manufactured into ingots for experimental characterization. This included microstructure analysis to determine phase fractions and phase compositions, and alloy hardness. The measured CuSn gamma phase fraction and hardness values for the manufactured ingots prior to infiltration are shown in Table 1. Hardness (HV_0.2) was measured using the Vickers hardness test with an applied load of 0.2 kgf and a loading time of 15 seconds.

TABLE 1
Experimental Ingot Results
		AgCu γ Phase	CuSn γ Phase	Hardness
	Ingot	Fraction	Fraction	(HV0.2)
	X1		18%	313
	X2		31%	224
	X3		52%	293
	X4		27%	196
	Ag20	13%		105
	Ag40	37%		109

The four experimental alloys were then infiltrated into a tungsten matrix powder to simulate industrial core drill bit manufacturing conditions, and evaluated. The procedure utilized a graphite mold to cast 12.7 mm diameterט100 mm long pins. The molds were first filled with fine tungsten powder. The tungsten powder was then pressed with an applied load of 350 lbs to achieve a pressing pressure of 1783 psi. Next, the copper binder alloy and a mixture of flux was place into the mold cavity above the tungsten powder. The mold was then place into a furnace at 1100° C. to melt the binder alloy. Once molten, gravity causes the copper alloy to flow into the tungsten powder forming a solid infiltrated pin. The hardness and transvers rupture strength (TRS) of each pin was then characterized as follows.

Transverse rupture strength (TRS) was measured using a three-point bend test method with a span of 2 inches on test coupons formed as above, i.e., in the form of 0.5 inch (12.7 mm) diameter pins, approximately 4 inches (100 mm) in length. The applied load rate was 80 lbs/sec. The TRS value a is calculated from the following equation:

$\sigma =\frac{\mathrm{FL}}{\pi R^3}$

where σ is stress (psi); F is load (lbf); L is span (in); and R is pin radius (in).

Hardness (HV_0.3) was measured using the Vickers hardness test with an applied load of 0.3 kgf and a loading time of 15 seconds. The average of six hardness measurements was used to quantify the hardness of each infiltrated pin. Results are shown in Table 2.

TABLE 2
Experimental Results for Infiltrated Pins
	Pin	Pin	Pin
Infiltrated	Hardness at	Hardness at	Density	TRS	TRS
Pin	Top (HV0.3)	Bottom (HV0.3)	(g/cm3)	(ksi)	(MPa)
X1	388	380	13.42	103.1	710.4
X2	339	290	13.23	87.2	600.8
X3	396	395	13.46	40.9	281.8
X4	298	303	13.13	86.4	595.3
Ag20	214	158	13.53	95.1	655.2
Ag40	204	195	13.54	125.5	864.7

Binder alloy X1 exhibited a transverse rupture strength (TRS) of 103 ksi (or 710 MPa) and the X3 alloy exhibited a TRS of 41 ksi (or 282 MPa). In comparison the Ag20 core binder alloy run under similar infiltration conditions had a TRS of 95 ksi (or 655 MPa).

Binder alloy X1 is an example of a pro-eutectic alloy. FIG. 1 shows the thermodynamic behavior of X1 wherein the FCC Cu matrix 101, is present at a higher temperature and thus forms in advance of the CuSn gamma phase 102 during solidification. FIG. 2 shows the microstructure of solidified binder alloy X1 comprising primarily FCC Copper 201 with CuSn gamma phase precipitates 202.

As seen in FIG. 1, binder alloy X1 has a CuSn gamma phase fraction at solidus of about 25 mol %. X1 has a liquidus of 1290K and a solidus of 1165K resulting in a 125K mushy zone.

In the low-Ag (including Ag-free) binder alloys disclosed herein, the binder alloy can be designed to form a perfect eutectic, alloy X3, such as shown in FIG. 3 and FIG. 4. FIG. 3 shows how both the FCC Cu matrix phase 301 and the CuSn gamma phase 302 form at the same temperature. The microstructure of this alloy is shown in FIG. 4 showing Cu FCC phase 401 and CuSn gamma phase 402. As noted, the CuSn gamma phase precipitate fraction 402 is significantly higher than in the pro-eutectic alloy case.

As seen in FIG. 3, binder alloy X3 has a CuSn gamma phase fraction at solidus of about 61 mol %. X3 has a liquidus of 1131K and a solidus of 1075K resulting in a 56K mushy zone.

Scanning electron microscopy for alloys X1 and X3 are shown in FIG. 5 and FIG. 6 respectively. Both micrographs shows tungsten particles, 502 and 602 well bonded to the binder alloys 501, 601 (Cu-rich) and 603 (Sn-rich).

The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.

The foregoing examples are provided merely for explanation, and are not to be construed as limiting the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims, as presently stated and as amended.

Claims

1. A binder alloy comprising 1-33 wt % Ni, 11-38 wt % Sn, and Cu, wherein Cu is the plurality or majority component, and wherein the binder alloy comprises less than 10 wt % Ag, and less than 20 wt % Zn.

2. The binder alloy of claim 1 satisfying at least one of the following formulas: comprising less than 5 wt % Ag, less than 5 wt % Zn, and a balance of Cu.

17-33 wt % Ni,12-24 wt % Sn,  (A1)

4-8 wt % Ni,15-29 wt % Sn,  (A2)

7-13 wt % Ni,20-28 wt % Sn,  (A3)

1-3 wt % Ni,14-27 wt % Sn, or  (A4)

6-12 wt % Ni,11-21 wt % Sn  (A5)

3. An abrasive article comprising an abrasive material in a matrix comprising the binder alloy of claim 1.

4. An abrasive article comprising an abrasive material in a matrix comprising the binder alloy of claim 2.

5. The binder alloy of claim 2 having a mushy zone of 150K or less.

6. The binder alloy of claim 2, comprising a matrix microstructure comprising a CuSn gamma phase, wherein the CuSn gamma phase comprises 0.1% to 70% of the matrix microstructure

7. The abrasive article of claim 3, wherein the abrasive article is a core drill bit.

8. The drill core bit of claim 7 having Vickers hardness HV0.3 of 250 or greater.

9. The drill core bit of claim 7 having TRS of 200 MPa or greater.

10. A process for manufacturing an abrasive article comprising:

placing an abrasive particulate material into a mold;

melting a binder alloy according to claim 1 to obtain a molten binder;

allowing the molten binder to enter the mold and contact the particulate material to obtain a coated particulate material; and

cooling the coated particulate material to obtain the abrasive article.

11. The binder alloy of claim 1 comprising 17-33 wt % Ni and 12-24 wt % Sn.

12. The binder alloy of claim 11 comprising 17-33 wt % Ni, 12-24 wt % Sn, and the balance copper.

13. The binder alloy of claim 1 comprising 21-29 wt % Ni and 15-21 wt % Sn.

14. The binder alloy claim 13 comprising 21-29 wt % Ni, 15-21 wt % Sn, and the balance copper.

15. A process for manufacturing an abrasive article comprising:

placing an abrasive particulate material into a mold;

melting a binder alloy according to claim 11 to obtain a molten binder;

allowing the molten binder to enter the mold and contact the particulate material to obtain a coated particulate material; and

cooling the coated particulate material to obtain the abrasive article.

16. A process for manufacturing an abrasive article comprising:

placing an abrasive particulate material into a mold;

melting a binder alloy according to claim 13 to obtain a molten binder;

allowing the molten binder to enter the mold and contact the particulate material to obtain a coated particulate material; and

cooling the coated particulate material to obtain the abrasive article.