CA1238309A

CA1238309A - Copper-based spinodal alloy bearings

Info

Publication number: CA1238309A
Application number: CA000473398A
Authority: CA
Inventors: Nareshchandra J. Kar
Original assignee: Smith International Inc
Current assignee: Smith International Inc
Priority date: 1984-02-09
Filing date: 1985-02-01
Publication date: 1988-06-21
Also published as: GB2153882B; IT1182429B; IT8567134A0; GB2153882A; IT8552982V0; GB8502757D0; IT8567134A1

Abstract

ABSTRACT OF THE DISCLOSURE

This invention relates to the use of copper-based spinodal alloys, for example, copper-nickel-tin alloys, for bearing surfaces formed between a journal shaft and a roller cutter cone of a sealed bearing rock bit.

Description

a~ - b~

COPPER-BASED SPINODAL ALLOY BEARIN~S
~CKGR~UND OF THE INVENTION
1. Field of the Invention ~ his invention pertains to heavy-duty, friction type bearings.
_ _ -More specificall~, this invention pertains to friction bearings utilized in sealed bearing roller cone rock bits.
The bearings of xoller cone rock bits typically 10 carry heavy loads (up to 40,000 pounds), plus intense and continual shock loads during bit operation. Rela-tive sliding velocities between the cone bearing sur-face and its associated journal bearing run from fifty to as much as five hundred surface feet per minute.
Lubrication is typically limited to self-contained non-circulating grease and bit operating temperatures, run between 150~ and 400 Fahrenheit.

2. Description of the Prior Art In the past, many materials and material systems have been used in the production of friction bearings for roller cone rock bits.
U S. Patent No. 3,721,307, for instance, specifies the use of beryllium copper in a rock bit bearing. Por-ous steel bearings produced from powdered metal and con-taining lubricants, such as graphite, in their inter-stices are described in U. S. Patent No. 4,105,263. Bear-ings wherein the steel members are treated to produce a special surface are also well known in the art. For exam-ple, U. S. Patent No. 4,012,238 describes a treatment in-volving the combined use of boronizing and carburizing to 1~3~ 3 produce a hardened ~case~ which i~ used as A bearing surface.
U.S. Patent No: 3,~95,917, describes the use of aluminum bronze in the pr~auction of a rock bit friction bearing~ Tungsten carbides have also been used, as~have stellite an~ other hard materials which =~
are applied by metallurgical hardfacing methods.
The useful life expectancy of these various ~ystems ~aries according to the particular drilling conditions under which they are used but are typically about 100 hours. Depending upon these conditions, lifetimes of from 20 hours tv about 150 hours are common.
SUMMARY OF THE INVENTION
A ~mall family of highly specialized alloy6, called copper-based ~pinodal alloys, developed in an art re-mote to either bearings or especially roller ~one rock bits, have been discovered to possess physical proper-ties advantageous to the production of rock bit fric-tion bearings. Spinodal alloys, in most cases, ex-hibit an anomaly in their phase diagram called a misci-bility gap. Within the very narrow temperature ranqe of the gap, ~tomic ordering ta~es place within the existing crystal lattice structure. The resulting two-phase structure is stable at temperatures significantly below the gap. A cast or wrought material is first solu-tion heat treated, permitting partial or full homogeniza-tion and annealing of the material, followed by a high-speed quench to freeze the fine grain 6tructure. Sub-sequently, the material is age-hardened by raising the material to a temperature within the miscibility gap. A

~L~3~3~

chemical segreation takes place called "spinodal decomposition"
wherein two new phases form, of similar crystallographic structure but of different composition.
An intermediate cold-working stage is sometimes introduced between the initial homogenization ~step and the final age-hardening to increase the dislocation density of the alloy.
Spinodal decomposition does not change the crystal structure of the lattice; hence there are no changes in part dimensions during this process. So processed, spinodal alloys offer high levels of tensile strength, elastic limit, resistance to stress relaxation and fatigue strength.
It has been discovered that copper-based spinodal alloys exhibit tribological properties that facilitate their application in lubricated, as well as non-lubricated, bearing applications as will become evident from the text of this disclosure. The primary family of copper-based spinodal alloys that have performed in a superior manner in our testing are copper-nickel-tin type spinodal alloys. These alloys consist primarily of copper containing nickel in an amount of from 2 to 20 percent by weight and tin in an amount of from 2 to 8 percent by weight. The preferred compositions are: 1) copper with 10 percent nickel and 8 percent tin and 2) copper with 15 percent nickel and 8 percent tin. Other spinodal alloys within the range of compositions could be used for similar superior bearing properties. Other families of copper-based spinodal alloys where the nickel and/or tin are replaced by elements such as chromium or iron also perform as spinodal bearings.

A copper-based spinodal alloy consisting essentially of copper-nickel-chromium may comprise 2 to 20 percent by weight nickel and 2 to 8 percent by weight chromium.
A copper-based spinodal alloy consisting essentially of copper-nickel-iron may comprise 2 to 20 percent by weight nickel and 2 to 8 percent by weight iron.
A copper-based spinodal alloy consisting essentially of copper-chromium-tin may comprise 2 to 20 percent by weight chromium and 2 to 8 percent by weight tin.
A copper-based spinodal alloy consisting essentially of copper-iron-tin may comprise 2 to 20 percent by weight iron and 2 to 8 percent by weight tin.
Copper-nickel-tin spinodal alloys that contain one or more additional elements such as iron, zinc, niobium, magnesium, zirconium, chromium or aluminum in total amount(s) not to exceed 15 percent by weight, would perform in a superior manner in bearing tests.
Small additions of lead and/or sulfur to improve the lubricity and

3~3 machinability of the disclo~ed coDDer-based sD1nodal ~lloys pe~form suitably in sucn ~earlngs.
Copper-nickel-tin ~pinodal ~lloys, hereafter ab-breviated ~s Cu-Ni-Sn type spinodal alloys, were daveloped by Bell Telephone L~oratories to provide ~ material of unusually high strength, simult~neously_ _ - with a material which for many years could resist corrosion ~nd erosion in a marine or submarine environ-ment.
A series of ~nited States patents relating to the making and processing of Cu-Ni-Sn type ~pinodal alloys have been assigned to Bell Telephone Laboratories.
Those patents of particular interest include the fol-lowing: No. 3,937,638 (METHOD FOR TREATING COPPER-NICK~L-TIN ALLOY COMPOSITIONS AND P~ODUCTS PRODUCED
THEREFROM)~ No. 4,052,204 (QUATERNARY SPINODAL COPPER
~LLOYS), NoO 4,090,890 (METHOD FOR MAXING COPPER-NICKEL-TIN STRIP MA~ERIAL) and No. 4,142,918 (METHOD
FOR MAKING FINE-GRAINED Cu-Ni-Sn ALLOYS).
None of the above patents suggest the use of these spinodal alloys for bearing applicationsO More impor-tantly, none of the above patents suggest the use of these spinodal alloys as bearing materials for roller cone rock bits, a particularly harsh environment for any type of bearing material.
The singular most unique feature of the Cu-Ni-Sn spinodal alloys shows up during the ~ging process.
~ensile str~ngth and ductility, normally mutually ex-clusive properties, are both very high after ~ging.
The degree to which the tensile strength is increased ~;~3~
in ~ging i~ highly dependent upon the degree of cold-working to which the material is ~ubjected after its ~olution treatment. The tensile strength can go as high as 200,000 pounds per square inch. Surprisingly, during this process, very little of the ductility is lost.
In a comprehensive comparative program of labora-tory testin~ on standard bearings, the Cu-Ni-Sn spino-dal candidates performed favorably ~bove the beryllium copper candidate.
The heat treatment schedules typically used to in-duce spinodal decomposition of the Cu Ni-Sn alloys were as follows. Cast or wrought materials were first solu-tion heat treated between 725 and 825~ Centigrade for 30 to 120 minutes to homogenize the alloys, followed by water quenching. The alloys were then aged between 350 and 425 Centigrade for between 3 to 5 hours to spinodally decompose the alloys, rendering materials of high hardness and high ductility.
An advantage of the use of Cu-Ni-Nn spinodal alloys is su~erior ductility. For example, beryllium copper has a hardness of about 38 Rockwell C (HRC), about the same as the Cu-Ni-Sn spinodal alloys, but the spinodal materials are much more ductile- a parameter that is highly desirable in bearing materials.
In addition, beryllium copper is more susceptible to fitress corrosion cracking and corrosion-related failures than the Cu-Ni-Sn spinodal alloys. Such en-vironments are commonly found in drill bit applications, such as, chlorides, sulfates, fiilicates, etc. These _~_ corrosive environments ~bra5ion, Mdhesion nnd cor-rosion) combined accelerate corrosive wear and ~horten the life of the bearing.
These types of ~ribological failures have been shown to be directly attributable to the ductility and toughness of any kind of bearing material. - -Being less ductile, beryllium copper is also moresusceptible to surface cracking and galling.
Cu-Ni-Sn spinodal alloys exhibit superior elonga-tion properties as well as greater ductility and tough-ness. ~he materials also have excellent resistance to applied stresses, thereby controlling erosion, crack-ing, etc.
Cu-Ni-Sn type spinodal materials, therefore, have a particular application in rotary cone rock bits. The rock bit bodies are generally fabricated from metal with at least one leg depending from the bit body. A
journal shaft depends from the leg. A metal roller cut-ter cone is adapted to be rotatively secured ~o the jour-nal shaft. A bearing material is disposed between the journal and the roller cutter~ The bearing materialcomprises copper-nickel-tin type spinodal alloys.
The above noted objects and advantages of the pres-ent invention will be more fully understood upon a studyof the following description in conjunction with the de-tailed drawings.

~ ~3~3~3 o_~4 BRIEF DESCRIPTION OF ~HE DRAWINGS
_ FIGURE 1 is a perspective view of a typical three cone rock bit;
PIGURE 2 is a partially broken away cross ~ection of one leg of the rock bit of FIGURE 1, illustrating the roller cone mounted-to-a journal bearing with a lu- -brication system communicating with the bearing surfaces defined between the journal bearing and the cone;
FIGURE 3 is a partially broken away leg of a rock bit, illustrating a journal bearing shaft and a cone mounted to the shaft with a metallurgically honded layer of Cu-Ni-Sn spinodal alloy in the bearing sur-faces defined by the cone;
FIGURE 4 is a graph comparing the Cu-Ni-Sn spinodal alloy with aluminum bronze and beryllium copper commonly utilized in the rock bit art;
FIGURE 5 is a partially broken away cross section of another embodiment of the present invention, illus-trating a sleeve of Cu-Ni-Sn spinodal alloy material pressed in a recessed cavity in the cone, the spinodal pressed-in sleeve acting as a bearing against the jour-nal shaft;
FIGURE 6 is a partially broken away cross section of still another embodiment of the present invention wherein a cylindrical ring of Cu-Ni-Sn spinodal mate-rial is pressed into a cavity in the cone, the inner surface of the spinodal material acting as a bearing surface against the bearing surfaces formed by the journal bearing;
FIGURE 7 is yet another embodiment of the pres-ent invention wherein a cylindrical floating ring of ~3~3.~3 83-64 Cu-Ni-Sn spinodal alloy ~aterial is plAced between a journal bearing and a bearing surface formed in the rotary cone; and FIGURE 8 is still ~nother embodiment of the pres-ent invention wherein a floating ring of Cu-Ni-Sn _ _ ~pinodai alloy material is positioned between ~ bear-ing surface formed in the cone and a bearin~ surface formed on the journal, DESCRIPTION OF THE PREFERRE:D EMBODIY~NTS AND
BEST MODE FOR CARRYING OUT T~E INVENTION
With reference to FIGURE 1, a roller cone rock bit, generally designated as 10, is depicted. A bit body 12 defines a pin end 16, adapted to receive drill segments (not chown) that make up a typical drillstring in a~
drilling operation. A series of legc 14 depend from the bit body 12. Each of the legs 14 support a roller cone, generally designated as 18. A multiplicity of cutter type elements 20 are strategically positioned on the cones to describe a specific cutting pattern in a borehole during bit operation. The types of cutters illustrated in FIGURE 1 are tungsten carbide inserts that are pressed into drilled holes in the cone body.
One or more nozzles 22 are positioned in the bit body 12 to pass drilling mud into the b3rehole bottom through each of the nozzles. A grease reservoir system, gener-ally designated as 24, provides a reservoir of lubricant (52) to the ~ealed bearings formed between the cones 18 and their respective journals 30.
With reference now to FIGU~E 2, one of the sectioned legs 14 illustrates the lubrication reservoir system 24. The system includes a pressure compensator boot 50 to accom-modate for differential pressures between the outside of the bit and the internal bearing surfaces of the bit.
The reservoir system includes a channel 54 to direct lu-bricant from the reservoir to the bearings defined be-tween the cone and the journal. The leg 14 terminates in a shirttail portion 15 (shown in both FIGS. 1 and 2).
A journal, generally designated as 30, is cantilevered ~3~3~3 from the leg 14 toward the centler of the bit. A ball race 40, transverse to the axis of t~e journal 30, is 60 positioned to register with ~ complementary ball race 21, formed in the cutter cone 18. A multiplicity of cone retention balls 42 are :inserted through a ball hole 44. The ball hole is drilled from the vutside shirttail portion 15 through the journal 30 to intersect the ball race 40. When the ball race 40 is filled with the balls 42, a ball plug 46 is then inserted in the ball hole 44 and secured by a welded cap 47. A relief portion 48 is formed in the ball plug 46 to admit lu-bricant from the yrease reservoir chamber 52 to bear-ing surfaces formed between the journal ~nd the c~e.
In FIGURE 2, the journal 30 ~has a chan-nel 34 in the journal bearing surface 32. The bottom or load side of the journal 30 is filled with a hard-facing material 36 (for example, a stellite material).
The upper portion of the channel 34 is left as a grease reservoir space 38 to provide a supply of lubricant to the bearing surfaces.
The cone, generally designated as 13, has an internal cavity 19 that serves as a cone bearing sur-face. A spindle bearing surface 26 is further formed within the cone 18 to complement a spindle bearing 33 that extends from the end of the journal bearing. The cone is, for example, fabricated from a metal, 6uch as 6teel. The cone surface is machined and drilled to ac-cept a multiplicity of, for example, tungsten carbide inserts 20 that are interference fitted within the drilled holes in the cone. The suxface of the cone ~L~3~;3~3 could, however, be machined to form equidistantly spaced milled teeth that form the cutting edge of each of the cones. A seal gland 27 may, for example, be cut into the entrance of the bearing 6urfaces in the cone 18, the seal gland being so configured to accept an O-ring ~ype geal 28. The O-ring forms a seal between the seal gland 27 and the journal bearing 34. Any type of seal may, however, be utilized without departing from the intent of the invention. A circumferential groove 23 is formed within the bearing surface 19 of cone 18, the groove generally registering with the groove 34 in journal 30. The groove 23 is subsequently filled with a Cu-Ni-Sn spinodal material which is metallurgically bonded within the annular groove 23 within cone 18.
The spinodal material, as heretofore stated, provides a good bearing surface after machining that is both tough and ductile to enhance the longevity of the rock bit as it works in a borehole. The machined spinodal bearing surface runs against, for example, the hard stellite material 36 that is metallurgically bonded within the groove 34 in the journal. The rock bit, as it works in a borehole, exerts pressure to the loaded side of the journal, thus contacting the spinodal bearing material bonded to the cone against the hardened surface 36 with-in the load side of journal 30.
Another bearing surface'37, known as a "snoochie", is~ormed in the journal 30. The snoochie surface pro~
vides an in-thrust bearing surface that mates with a complementary surface 39 formed in the cone cavity.
Although it is not illustrated, it would be obvious to ~l~3~3~9 use a spinodal material 6uch as Cu-Ni-Sn ~lloy on the ~noochie bearing 6urface formed on the journal or the complementary thrust bearing surface in the cone with-out departing from the teachings of this invention.
With reference now to ~IGURE 3, another embodiment of the present invention is depicted wherein the jou~
nal, generally designated as 130, i5 dependent from a leg 114. The bearing surface 132, however, lacks a circumferential annular groove in the journal as de-picted in FIGURE 2. The journal is machined to provide a bearing surface 132 in the parent material of the leg. The cone 118 has an annular groove 123, machined in the bearing surfaces 119, the groove being filled with a Cu-Ni-Sn spinodal alloy material 125 in the same manner as was done with the cone of FIGURE 2. The spinodal material is subsequently machined and provides a primary bearing surface for the bearing 132 of jour-nal 130.
Journal bearing 130 has a spindle 133 extending from the thrust bearing end 137 (snoochie) of the journal. A spindle bearing surface 134 runs against co~plementary bearing surface 126 in cone 118. Either the spindle or the cone could have a channel filled with a Cu-Ni-Sn spinodal material 125 to provide a superior bearing surface between the spindle and the cone. A series of cone retention balls 142 are con-fined within ball races 140/121 in journal 130 and cone 118. A similar ball plug 146 is housed within a ball plug hole 144 and held in place with ~ welded cap 147 in shirttail 115. A seal 128 prevents leakage 3l~3~ 83-64 of lubricant from the bearing ~urfaces defined be-tween the ~ournal ~nd the cone.
Turni~g now to FIGURE 4, the chart il~ustrated depicts the tensile strength and ductility of three different bearing type materials, For example, in the - first column,~aluminum bronze has a tensile strength of 7000kg/sq~cm. (lOOKSI) and a ductility of 1~. Beryllium copper sho~s a tensile strength of 14,000 kg/sq.cm.
(200KSI) with a 1~ ductility factor while the Cu-Ni-SN
spinodal alloy material has a tensile strength of 13,400 kg/sq.cm. ~19OKSI) with a 4% ductility factor. Clearly then, the Cu-Ni-SN spinodal alloy material has a greater than or substantially equal tensile strength when compared to alumin~m bronze or beryllium copper--with a much higher ductility factor than either, which is advantageous when used as a bearing material, especially in the rock bit art.
~urning now to still a differen~ embodiment, il-lustrated in ~IGURE 5, a spinodal material (such as Cu-Ni-Sn) is formed in hollow right cylinder and gen~rally designated as 224. The cylinder of spinodal material 225 is pressed into an annular recess 223, formed in cone 218. The journal 230 has a channel 234 formed in the journal 30 of FIG. 2. The loaded side 236 of the journal is filled with a hard metal. The unloaded side 238 of the channel 234 provides a grease reservoir for the bearings formed between the journal and the cone. Again, the cone is retained on the journal by a series of cone retention balls 242 that track within races 221 and 240, formed between the cone ~nd the ~3~3~ ~3-6~
journal. A ball plug 246 secures the balls within their track. The internal diameter 226 of the ring of spinodal material 225 is machined with ~ppropriate bearing tolersnces to conform to the bearing surfnce 232 of the journal 230. In the embodi-ment shown in FIGVRE 5 the spin~- ;
dal material 225 may be pressed or interference fit-ted within a complementary channel 223 formed in the cone without metallurgically bonding the ring of spinodal material within the cone.
FIG~RE 6 is yet another embodiment wherein a simiIar ring of spinodal material, ~uch as Cu-Ni Sn alloy and generally designated as 324, is pressed within ~
complementary channel 323 in cone 318. The difference between FIGURE 6 and FIGURE S is that the journal 330 is machined from the basic material of the leg 314 (without the circular track 234, shown in FIGURE 5).
The inner machine bearing surface 326 in the spinodal material 325 runs against a complementary machined bearing surface 331 of the journal 330. A spindle 333 extends from the end of the journal 330 and mates within a complementary annular recess formed in cone 318. Again, an O-ring 328 is housed within a seal gland 327 formed in the cone 318. The seal ~cts to retain lubricant within the bearing ~urfaces formed between the journal and the cone.
FIGURES 7 and 8 depict still different embodiments of the present invention. FIGURE 7 illustrates a jour-nal bearing 430 with a circumferential groove formed on the surface of the journal, the groove having the ~3~
hardfacing material on the loaded 6ide of the groove ~36 with the open or unloaded side of the groove 438 ncting as a lubricant reservoir ~6 heretofore mentioned.
A cylindrical floating bearing ring, generally desig-nated as 424, is fabricated from Cu-Ni-Sn spinodai material 425. The inner ~nd outer bearing 6urfaces 426 and 427 are ~o machined to act as bearing surfaces between the journal bearing 431 ~nd the cone bearing 419. The ring of spinodal material 425 now ~cts as a floating ring between the journal and the cone. By utilizing a floating ring of spinodal material, the slip speeds (surface feet per minute) between the cone and the journal ~re divided by the bearing ~urface~ 426 and 427 of the ring of ~pinodal material. Thus, the surface fee~ per minute is halved between a journal bearing surface and a cone bearing ~urface when com-pared to a conventional bearing between a journal and a cone. A series of cone retention balls 442 are nest-ed within ball bearing races 440 in the cone and a simi-lar race in the journal and are retained within their race by means heretofore described. Again, an O-ring 428 is confined within a seal gland 429 in the cone 418.
Finally, FIGURE 8 depicts a floating ring, generally designated as 524. The ring of a Cu-Ni-Sn spinodal mate-rial 525 floats between a journal bearing 530 and a cone 518. Again, both the inner cylindrical surface 526 and the outer cylindrical surface 527 of the spinodal mate-rial 525 acts as a bearing surface between the journal bearing ~urface 531, formed of the basic material of the journal 530. The hardfacing is absent from the 1~3~3~ o~-n~

configuration as illustrated in FIGURE 8. The cone, ngain, is being retained by ~ series of balls 544 with-in ball races formed between the cone ~nd the ~ournal.
It would be obvious to press or metallurgically bond a ring of Cu-Ni-Sn ~pinodal material to the ~our-nal bearing shafts of FIGS. 3,-6-and 8.
~ It would ~dditionally be obvious to provide the Cu-Ni-Sn spinodal bearing material to both the cone recess ~nd the journal without departing from the teachings of this invention.
It will of course be realized that various modi-fications can be made in the design and operation of the present invention with~ut departing from the spirit thereof. ~hus, while the principal preferred construction and mode of operation of the invention have been explained in what is now considered to rep-resent its best embodiments, which have been illus-trated and descr.ibed, it should be understood that within the scope of the appended claims, the inven-tion may be practiced otherwise than as specificallyillustrated and described.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A rotary cone rock bit comprising:
a rock bit body, at least one leg depending from said body, a journal shaft on said leg, a roller cutter cone adapted to be rotatively secured to said journal shaft, and bearing surfaces formed by said journal and said cone, one of said bearing surfaces having a corrosion resistant bearing material disposed thereon, said bearing material consisting of a copper-based spinodal alloy which has been solution heat treated, quenched and aged to spinodally decompose and harden the alloy to have a tensile ductility of at least four percent, the other of said bearing surfaces being formed of a material harder than said spinodal alloy.

2. The invention as set forth in claim 1, wherein the spinodal alloy has a Rockwell C hardness of about 38.

3. The invention as set forth in claim 1, wherein said bearing material is metallurgically bonded to bearing surfaces formed within said cone.

4. The invention as set forth in claim 1, wherein said bearing material is formed in a cylindrical ring, said ring being so dimensioned to float between said journal shaft and said roller cutter, the inner and outer surfaces of said floating ring serving as bearing surfaces adjacent complementary bearing surfaces formed by said journal and said roller cutter.

5. The invention as set forth in claim 2, wherein said journal shaft has a circumferential groove in a bearing surface formed by said shaft, said groove being transverse to an axis of said shaft, a portion of said groove being filled with a hardfacing metal for acting as a bearing when said cone bearing surface is loaded against said shaft bearing surface during rock bit operation.

6. The invention as set forth in any one of claims 1 to 3, wherein said bearing material is formed in a cylindrical ring, said ring being interference fitted within a complementary cavity formed in said roller cutter, an inner surface of said cylindrical ring forming a bearing surface for said journal shaft.

7. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloy comprises 2 to 20 percent by weight nickel and 2 to 8 percent by weight tin.

8. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-tin.

9. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-tin, said copper-nickel-tin spinodal alloy consisting essentially of copper having about 15 percent by weight nickel and about 8 percent by weight tin.

10. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-tin, said copper-nickel-tin spinodal alloy consisting essentially of copper having about 10 percent by weight nickel and about 8 percent by weight tin.

11. The invention as set forth in any one of claims 1 to 3, wherein said copper based spinodal alloys consist essentially of copper-nickel-tin, said copper-nickel-tin spinodal alloy containing about 1 percent by weight sulfur.

12. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-tin, said copper-nickel-tin spinodal alloy containing about 1 percent by weight lead.

13. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-tin, said copper-nickel-tin spinodal alloy containing a fourth metal selected from the group consisting of iron, zinc, niobium, magnesium, zirconium, chromium, aluminium.

14. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-tin, said copper-nickel-tin spinodal alloy containing a fourth metal selected from the group consisting of iron, zinc, niobium, magnesium, zirconium, chromium, aluminium, said copper-nickel-tin spinodal alloy containing up to 15 percent by weight of said fourth metal.

15. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-chromium.

16. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-chromium, and wherein said copper-based spinodal alloy comprises 2 to 20 percent by weight nickel and 2 to 8 percent by weight chromium.

17. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-iron.

18. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-nickel-iron, and wherein said copper-based spinodal alloy comprises 2 to 20 percent by weight nickel and 2 to 8 percent by weight iron.

19. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloy consists essentially of copper-chromium-tin.

20. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloy consists essentially of copper-chromium-tin, and wherein said copper-based spinodal alloy comprises 2 to 20 percent by weight chromium and 2 to 8 percent by weight tin.

21. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-iron-tin.

22. The invention as set forth in any one of claims 1 to 3, wherein said copper-based spinodal alloys consist essentially of copper-iron-tin, and wherein said copper-based spinodal alloy comprises 2 to 20 percent by weight iron and 2 to 8 percent by weight tin.