FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
An electrical contact and a method of making the electrical contact
APPLICANT (S)
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S)
Tanneeru Rakesh, Jena Sushil Kumar, Nemade Janamejay Bhalchandra of Crompton Greaves Limited, Advanced Materials and Process Technology Centre, CG Global R&D Centre, Kanjur Marg (E), Mumbai, Maharashtra, India; and Rayudu Srinivas of Crompton greaves limited ,Vacuum interrupters and Instrument transformer division, Waluj , Aurangabad , Maharashtra, India; all Indian Nationals.
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
This invention relates to the field of alloys.
Particularly, this invention relates to the field of alloys for electrical contacts.
Still particularly, this invention relates to vacuum interrupter contacts.
More particularly, this invention relates to an electrical contact and a method of making the electrical contact.
BACKGROUND OF THE INVENTION:
A composite radial magnetic field (RMF) electrical contact material is developed for vacuum Interrupter (VI) application.
Vacuum interrupter contacts desire the following properties, ideally, for improving the working parameters of the associated vacuum interrupters:
a. Low gas content
b. Minimal welding
c. Low thermionic emission
d. Optimum vapour pressure
e. Optimum erosion
f. Mechanical strength
g. Voltage withstand
h. High electrical conductivity
i. High thermal conductivity
j. Anti-welding tendency
k. Interrupting ability

Previously, according to the prior art, many combinations of element have been tried, tested, and used for manufacturing contacts, preferably vacuum interrupter contacts. The following was observed:
For Cu-Cr contact material, the advantages include the following:
a. After high current interruption the contact surface remains smooth
b. The surface of the contact changes to very finely disperse Cr in a Cu matrix
c. Excellent electrical endurance
d. Excellent mechanical strength
e. Excellent high-voltage performance
f Withstands high-speed TRVs
g. Low cost
h. Adequate resistance to contact welding in circuit breaker applications
i. Excellent high, short-circuit interruption performance
j. Butt contacts interrupt up to 10 kA
k. Maximum chop current <6A
However, for Cu-Cr contact material, the disadvantages include the following:
a. Excellent high-frequency current interruption can result in voltage escalation in
high inductance circuits
b. Welding tendency too high for contactor applications
For Ag-WC contact material, the advantages include the following:
a. Excellent load current electrical endurance (>106 electrical operations possible)
b. Poor high-frequency current interruption, limits high-voltage escalation effects,
that is, it is a "low surge" contact material
c. Excellent resistance to contact welding
d. Maximum chop current <2A

However, for Ag-WC contact material, the disadvantages include the following:
a. High cost
b. Butt contact interruption limit 4-4.5 kA
c. Requires an AMF, design to reach higher short-circuit interruption values
d. High-voltage performance generally limited to 15 kV or lower systems
e. Use generally limited to contactor applications
f. For Cu-W contact material, the advantages include the following:
g. Excellent load current electrical endurance
h. High-frequency current interruption ability between that of Cu-Cr and Ag-WC
i. Excellent high-voltage performance
j. Good resistance to contact welding
k. Low cost
l. Maximum chop current <8A
However, for Cu-W contact material, the disadvantages include the following:
Butt contact interruption limit 2-3 kA
Use generally limited to load break switches
If Cu-Bi is chosen to alter the present contact materials, the element Bi is desirable for low chopping current. However, the Cu-Bi combination provides a mechanically weak contact material, voltage withstand ability is low and erosion is high. With small addition of Bi to Cu, Bi migrates to the grain boundary of Cu during solidification. This makes contact more brittle than pure Cu. Inherent defect form.
If Cu-Ag is chosen to alter the current contact materials, it is observed that Silver is not used because of high cost and not real advantage over Cu in vacuum environment,

It is not possible to get all the requirements by a single contact material as some of them are contradictory.
For example, copper chromium contact materials are a widely accepted contact material for vacuum interrupter (VI) application. Copper-Chromium (CuCr) contact materials are used in varied compositions depending on the desired property requirements. Cu:Cr::75:25 (consists of copper (Cu) by 75% weight and Chromium(Cr) 25% by weight) is used for its good electrical, thermal conductivities and interrupting ability at the expense of good anti-welding tendency and voltage withstand ability property.
Whereas Cu:Cr::50:50 (consists of copper (Cu) by 50% weight and Chromium (Cr) 50%) by weight) is used for applications desiring high voltage withstand ability and anti-welding tendency at the expense of electrical and thermal conductivity.
It is not feasible to achieve all the properties by a single contact material as some of them are contradictory.
There is need for an improved contact material which could meet the expectations of all the desired properties.
PRIOR ART:
GBl510176 relates to a powdered metallurgical process for forming vacuum interrupter contacts. Here, manufacturing the contacts by infiltration process involves additional step of pre-sintering. This method, hence, becomes a relatively costly process. Further, the compact mentioned herein has variable porosity which is an undesired aspect. This patent document mentions that the chromium concentration varies and is related to cross section, which is again not a desirable

condition. The properties of high anti-welding tendency in annular region and high interrupting ability at petal region cannot be obtained by maintaining the composition and variable porosity in green compact as cited in the patent.
Hence, there is a need for a better electrical contact, better electrical contact material, and a method of making, thereof
OBJECTS OF THE INVENTION:
An object of the invention is to provide an improved contact material.
Another object of the invention is to provide an improved contact material with optimum erosion characteristics.
Yet another object of the invention is to provide an improved contact material with enhanced mechanical strength.
Still another object of the invention is to provide an improved contact material which withstands voltage.
An additional object of the invention is to provide an improved contact material with high electrical conductivity.
Yet an additional object of the invention is to provide an improved contact material with high thermal conductivity.
SUMMARY OF THE INVENTION:
For the purposes of this specification, an electrical contact is considered in its cross-section which is a cylindrical cross-section. This consists of a 'petal region' which is a circumferential region having a pre-defmed differential radius. The

remainder portion which is concentric to the petal region is the 'annular region', which annular region is the core of the cylindrical cross-section.
According to this invention, there is provided an electrical contact comprising:
a. annular region of said contact being made up of a composition comprising
about 50% to 60% by weight of Copper and about 50% to 40% by weight of
Chromium, said annular region having a height in the range of about 3mm to
6mm from the operative top of said electrical contact; and
b. petal region of said contact being made up of a composition comprising
about 70%) to 80% by weight of Copper and about 30% to 20% by weight of
Chromium.
Preferably, according to this invention, there is provided an electrical contact comprising:
a. annular region of said contact being made up of a composition comprising
about 50%) by weight of Copper and about 50% by weight of Chromium,
said annular region having a height in the range of about 3mm to 6mm from
the operative top of said electrical contact; and
b. petal region of said contact being made up of a composition comprising
about 75%) by weight of Copper and about 25% by weight of Chromium.
Alternatively, said electrical contact comprises:
a. annular region of said contact being made up of a composition comprising about 50% by weight of copper and about 50%) by weight of chromium having a height of 3mm to 6mm from the operative top of said electrical contact, said annular region being obtained by initially taking a blended

mixture of copper and chromium consisting of 47% by weight of copper and 53% by weight of chromium; and b. petal region of said contact being made up of a composition comprising 75% by weight of Copper and 25% by weight of Chromium, said petal region being obtained by initially taking a blended mixture of copper and chromium consisting of 76%) by weight of copper and 24% of chromium by weight
According to this invention, there is provided a method for making an alloy adapted to be used for manufacturing electrical contacts, said method employs the steps of: i. first step of making a first blended mixture consisting of 47% by weight of
copper and 53% by weight of Chromium; ii. second step of making a second blended mixture consisting of 76%) by weight
of copper and 24% by weight of Chromium; iii. third step of compacting said first blended mixture with a first top punch by inserting second top punch at compaction pressure of up to 30% of final compaction pressure and later ejecting said first top punch and said second top punch; iv. fourth step of filling a second die with said second blended mixture and compacting it with a third top punch with a final compaction pressure to obtain green compacts, said green compacts being subjected to isostatic compaction; and v. fifth step of subjecting said green compacts to liquid phase sintering process at temperatures above 1100°C, thereby achieving an electrical contact being a substantially cylindrical contact having an annular region of said contact being made up of a composition comprising about 50% by weight of Copper and

about 50% by weight of Chromium, said annular region having a height in the range of about 3mm to 6mm from the operative top of said electrical contact; and a petal region of said contact being made up of a composition comprising about 75% by weight of Copper and about 25% by weight of Chromium.
According to another embodiment of this invention, there is provided a method for manufacturing of composite radial magnetic field (RMF) contacts, said method employs the steps of:
i. first step of making a first blended mixture consisting of 47% by weight of copper and 53%) by weight of Chromium;
ii. second step of making a second blended mixture consisting of 76% by weight of copper and 24% by weight of Chromium;
iii. third step of compacting said first blended mixture with a first top punch by inserting second top punch at compaction pressure of up to 30% of final compaction pressure and later ejecting said first top punch and said second top punch;
iv. fourth step of filling a second die with said second blended mixture and compacting it with a third top punch with a final compaction pressure to obtain green compacts, said green compacts being subjected to isostatic compaction; and
v. fifth step of subjecting said green compacts to liquid phase sintering process at temperatures above 1100°C, thereby achieving an electrical contact being a substantially cylindrical contact having an annular region of said contact being made up of a composition comprising about 50% by weight of Copper and about 50% by weight of Chromium, said annular region having a height in the range of about 3 mm to 6mm from the operative top of said electrical contact;

and a petal region of said contact being made up of a composition comprising about 75% by weight of Copper and about 25% by weight of Chromium.
According to yet another embodiment of this invention, there is provided an
electrical contact made of composite material of Copper and Chromium, said
contact made employs the process steps of:
i. first step of making a first blended mixture consisting of 47% by weight of
copper and 53% by weight of Chromium; ii. second step of making a second blended mixture consisting of 76% by weight
of copper and 24% by weight of Chromium; iii. third step of compacting said first blended mixture with a first top punch by inserting second top punch at compaction pressure of up to 30% of final compaction pressure and later ejecting said first top punch and said second top punch; iv. fourth step of filling a second die with said second blended mixture and compacting it with a third top punch with a final compaction pressure to obtain green compacts, said green compacts being subjected to isostatic compaction; and v. fifth step of subjecting said green compacts to liquid phase sintering process at temperatures above 1100°C, thereby achieving an electrical contact being a substantially cylindrical contact having an annular region of said contact being made up of a composition comprising about 50% by weight of Copper and about 50% by weight of Chromium, said annular region having a height in the range of about 3mm to 6mm from the operative top of said electrical contact; and a petal region of said contact being made up of a composition comprising about 75% by weight of Copper and about 25% by weight of Chromium.

Typically, said first die is a first hollow cylindrical die having a first diameter dimensions and a first height dimensions.
Typically, said second die is a second hollow cylindrical die having a second diameter dimensions and a second height dimensions.
Typically, said first bottom punch is a solid cylindrical die having a first diameter dimensions and a fifth height dimensions.
Typically, said first top punch includes two co-axial cylinders; one atop another with varying pre-defined dimensions.
Typically, said second top punch includes two co-axial cylinders; one atop another with varying pre-defined dimensions, hollow throughout.
Typically, said third top punch includes two co-axial cylinders; one atop another with varying pre-defined dimensions.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a cut cross-section view of the electrical contact;

Figure 2 illustrates a side view of the electrical contact;
Figure 3a illustrates radial magnetic field contacts;
Figure 3b illustrates composite RMF contacts;
Figure 4a and Figure 4b illustrates a first Die;
Figure 5a and Figure 5b illustrates a second Die;
Figure 6 illustrates a first Bottom punch;
Figure 7a illustrates a first Top punch;
Figure 7b illustrates a second Top punch;
Figure 7c illustrates a third Top punch;
Figure 8a illustrates an image through a scanning electron microscope (SEM) of
annular region of electrical contact of the invention at 200X;
Figure 8b illustrates an image through a scanning electron microscope (SEM) of petal region of electrical contact of the invention at 200X; and
Figure 8c illustrates an image through a scanning electron microscope (SEM) of Boundary between annular and petal region of electrical contact of the invention at 200X.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided a method for making an alloy adapted to be used for manufacturing electrical contacts. This method is particularly deployed for manufacturing of composite radial magnetic field (RMF) contacts.
The metals used in this preparation are Copper (Cu) and Chromium (Cr).
Thus, a composite CuCr contact material is developed without complementing their mutual deficiencies in performances. This is obtained by maintaining the desired composition of copper and chromium in the various locations of the geometry of RMF contacts. RMF contact consists of two regions i.e.
1) annular region (as shown in Figure 1 of the accompanying drawings); and
2) petal region.
Contacts mate at annular region and current interruption takes place at petal region. Annular region desires material of good anti-welding tendency property whereas petal region desires material with good interrupting ability. Thus, a composite contact material is developed which consists of material with good anti-welding tendency at annular region and good interrupting ability material at the petal region.
Material consisting of Copper in 75% proportion and Chromium in 25% proportion (Cu:Cr::75:25) is widely accepted for RMF contacts. It has high thermal and

electrical conductivity, good interruption ability, but poor anti-welding tendency when compared to contact material consisting of Copper in 50% proportion and Chromium in 50% proportion (Cu:Cr::50:50). Thus, composite contact material is developed for improved anti-welding tendency.
Figure 1 illustrates a cut cross-section view of the electrical contact (100). Figure 2 illustrates a side view of the electrical contact (100).
In accordance with an embodiment of this invention, there is provided an electrical contact which consists of Cu:Cr::50:50 in the annular region (12) of the contact and Cu:Cr::75:25 in the petal region (14) of the contact.
Figure 3a illustrates radial magnetic field contacts. Figure 3b illustrates composite RMF contacts.
The contact material developed does not complement any mutual deficiencies of contact material properties required for performance unlike contact materials as per previous inventions on CuCr contact materials.
The contact material during its entire short circuit current switching life would wear up to only 3-6mm of its height. The remaining bulk does not participate directly during short-current switching and instead decreases the bulk thermal and electrical conductivity effecting interrupting ability of contact material.
Thus, in accordance with another embodiment of this invention, the composite electrical contact developed, Cu:Cr::50:50 in the annular region is restricted to

only 3-6mm and the remaining bulk consists of Cu:Cr::75:25, in order to improve thermal and electrical conductivity.
According to another embodiment of this invention, there is provided a method of making the electrical contact.
The two different compositions of copper and chromium powders were made by mixing them in the desired proportion.
In accordance with an embodiment of this invention, there is provided a first step of making a first blended mixture consisting of 47% by weight of copper and 53% by weight of Chromium.
In accordance with another embodiment of this invention, there is provided a second step of making a second blended mixture consisting of 76%) by weight of copper and 24% by weight of Chromium.
The compositions of blends are selected in order to obtain final desired compositions i.e. Cu:Cr::50:50 at annular region and Cu:Cr::75:25 at petal region.
The following components are used for the method and process:
first Die - first hollow cylindrical die having a first diameter and a first height.
second Die - second hollow cylindrical die having a second diameter and a second
height.
First Bottom punch - solid cylindrical die having a first diameter and a fifth height.

First Top punch - two co-axial cylinders; one atop another with varying predefined dimensions.
Second Top punch - two co-axial cylinders; one atop another with varying predefined dimensions, hollow throughout.
Third Top punch - two co-axial cylinders; one atop another with varying predefined dimensions.
In accordance with yet another embodiment of this invention, there is provided a third step of compacting first blend with a first top punch by inserting second top punch at compaction pressure of up to 30% of final compaction pressure. The punch and core rod are ejected.
In accordance with still another embodiment of this invention, there is provided a fourth step of filling a second die with second blend and compacting it with third top punch with final compaction pressure. The green compacts are then subjected to isostatic compaction, if required.
In accordance with yet another embodiment of this invention, there is provided a fifth step of subjecting the green compacts to liquid phase sintering process at temperatures above 1100°C. This results in a composite electrical contact which consist of Cu:Cr::50:50 in the annular region which extends up to 3-6mm of thickness and remaining bulk consists of Cu:Cr::75:25.
According to a non-limiting exemplary embodiment of this invention, test results were obtained by developing the Composite radial magnetic field (RMF) contacts

The physical properties like density, electrical conductivity, hardness, chemical composition and microscopy were carried out to characterize electrical contact materials. The testing and analysis was carried out on composite RMF contact material developed in the annular region and the petal region.
The physical properties of the electrical contact were as listed below in Table 1:

Region Density
(gms/cc) Electrical
Conductivity(%IACS) Hardness (HRF)
Annular 7.9-8.0 30-36%IACS 70-75
Petal 8.2-8.3 41-45%IACS 55-60
TABLE 1
The chemical analysis of the electrical contact were as listed below in Table 2:

Region Copper (Wt%) Chromium (Wt %)
Annular 57.11 42.40
Petal 75.84 23.38
TABLE 2
Figure 8a illustrates an image through a scanning electron microscope (SEM) of
annular region of electrical contact of the invention at 200X.
Figure 8b illustrates an image through a scanning electron microscope (SEM) of
petal region of electrical contact of the invention at 200X.
Figure 8c illustrates an image through a scanning electron microscope (SEM) of
Boundary between annular and petal region of electrical contact of the invention at
200X.

It was observed that the difference in the densities indicates the difference in the composition of the annular region and the petal region (as seen from Table 1). The density of the annular region is lower than that compared to the petal region, thus resembling higher composition of chromium in annular region. Similar is the case for the observations of lower electrical conductivity and higher hardness in annular region compared to petal region. The Chemical composition in the annular region indicates the copper and chromium to be nearly 57% by weight and 43% by weight respectively. The Chemical composition in the petal region indicates the copper and chromium to be nearly 75% and 25%) by weight respectively. The micrographs indicates uniform distribution of rounded chromium particles (Dark phase) in copper matrix (white phase). The micrographs of the annular region (Figure 8a) and petal region (Figure 8b) indicate the differences in the compositions maintained between the annular region and the petal region. It can be observed that larger fraction of area is occupied by chromium in case of annular region when compared to petal region due to its higher chromium composition. The boundary between annular region and petal region can be observed in Figure 8c.The distinguished microstructures across the boundary indicate varied composition of Chromium in both the regions.
Hence, it can be concluded that the desired compositions are successfully maintained in the annular regions and petal regions. The advantages of Cu:Cr::50:50 and Cu:Cr::75:25 are maintained in the composite radial magnetic field contacts.
[The contact material mentioned in the description is demonstrated by taking specific composition of Cu:Cr::50:50 in the annular region and Cu:Cr::75:25 in

the petal region. But the composition in the annular region may vary from any one of the composition consisting of 50-60 % by weight of copper (i.e. for example it may be Cu:Cr::50:50 or Cu:Cr::60:40) and in the petal region may vary from any one of the composition consisting of 70-80% of copper by weight (i.e. e.g; Cu:Cr::75:25 or Cu:Cr::80:20)]
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. An electrical contact comprising:
a. annular region of said contact being made up of a composition comprising
about 50% to 60% by weight of Copper and about 50% to 40% by weight
of Chromium, said annular region having a height in the range of about
3mm to 6mm from the operative top of said electrical contact; and
b. petal region of said contact being made up of a composition comprising
about 70%) to 80%> by weight of Copper and about 30% to 20%) by weight
of Chromium.
2. An electrical contact comprising:
a. annular region of said contact being made up of a composition comprising
about 50%o by weight of Copper and about 50% % by weight of Chromium,
said annular region having a height in the range of about 3mm to 6mm from
the operative top of said electrical contact; and
b. petal region of said contact being made up of a composition comprising
about 75%o by weight of Copper and about 25% by weight of Chromium.
3. An electrical contact comprising:
a. annular region of said contact being made up of a composition comprising about 50%) by weight of copper and about 50%) by weight of chromium having a height of 3mm to 6mm from the operative top of said electrical contact, said annular region being obtained by initially taking a blended mixture of copper and chromium consisting of 47%o by weight of copper and 53%) by weight of chromium; and

b. petal region of said contact being made up of a composition comprising 75% by weight of Copper and 25% by weight of Chromium, said petal region being obtained by initially taking a blended mixture of copper and chromium consisting of 76% by weight of copper and 24% of chromium by weight
4. A method for making an alloy adapted to be used for manufacturing electrical
contacts, said method employing the steps of: i. first step of making a first blended mixture consisting of 47% by weight of copper and 53% by weight of Chromium;
ii. second step of making a second blended mixture consisting of 76% by weight of copper and 24% by weight of Chromium;
iii. third step of compacting said first blended mixture with a first top punch by inserting second top punch at compaction pressure of up to 30%) of final compaction pressure and later ejecting said first top punch and said second top punch;
iv. fourth step of filling a second die with said second blended mixture and compacting it with a third top punch with a final compaction pressure to obtain green compacts, said green compacts being subjected to isostatic compaction; and
v. fifth step of subjecting said green compacts to liquid phase sintering process at temperatures above 1100°C, thereby achieving an electrical contact being a substantially cylindrical contact having an armular region of said contact being made up of a composition comprising about 50% by weight of Copper and about 50%) by weight of Chromium, said annular region having a height in the range of about 3mm to 6mm from the operative top of said electrical contact;

and a petal region of said contact being made up of a composition comprising about 75% by weight of Copper and about 25% by weight of Chromium.
5. A method as claimed in claim 4 wherein, said first die is a first hollow cylindrical die having a first diameter dimensions and a first height dimensions.
6. A method as claimed in claim 4 wherein, said second die is a second hollow cylindrical die having a second diameter dimensions and a second height dimensions.
7. A method as claimed in claim 4 wherein, said first bottom punch is a solid cylindrical die having a first diameter dimensions and a fifth height dimensions.
8. A method as claimed in claim 4 wherein, said first top punch includes two coaxial cylinders; one atop another with varying pre-defined dimensions.
9. A method as claimed in claim 4 wherein, said second top punch includes two co-axial cylinders; one atop another with varying pre-defined dimensions, hollow throughout.
10.A method as claimed in claim 4 wherein, said third top punch includes two coaxial cylinders; one atop another with varying pre-defined dimensions.
11.A method for manufacturing of composite radial magnetic field (RMF) contacts, said method employing the steps of:

i. first step of making a first blended mixture consisting of 47% by weight of copper and 53% by weight of Chromium;
ii. second step of making a second blended mixture consisting of 76% by weight of copper and 24% by weight of Chromium;
iii. third step of compacting said first blended mixture with a first top punch by inserting second top punch at compaction pressure of up to 30% of final compaction pressure and later ejecting said first top punch and said second top punch;
iv. fourth step of filling a second die with said second blended mixture and compacting it with a third top punch with a final compaction pressure to obtain green compacts, said green compacts being subjected to isostatic compaction; and
v. fifth step of subjecting said green compacts to liquid phase sintering process at temperatures above 1100°C, thereby achieving an electrical contact being a substantially cylindrical contact having an annular region of said contact being made up of a composition comprising about 50% by weight of Copper and about 50% by weight of Chromium, said annular region having a height in the range of about 3 mm to 6mm from the operative top of said electrical contact; and a petal region of said contact being made up of a composition comprising about 75%) by weight of Copper and about 25% by weight of Chromium.
12.An electrical contact made of composite material of Copper and Chromium,
said contact made employing the process steps of: i. first step of making a first blended mixture consisting of 47%) by weight of copper and 53% by weight of Chromium;

ii. second step of making a second blended mixture consisting of 76% by weight of copper and 24% by weight of Chromium;
iii. third step of compacting said first blended mixture with a first top punch by inserting second top punch at compaction pressure of up to 30% of final compaction pressure and later ejecting said first top punch and said second top punch;
iv. fourth step of filling a second die with said second blended mixture and compacting it with a third top punch with a final compaction pressure to obtain green compacts, said green compacts being subjected to isostatic compaction; and
v. fifth step of subjecting said green compacts to liquid phase sintering process at temperatures above 1100°C, thereby achieving an electrical contact being a substantially cylindrical contact having an annular region of said contact being made up of a composition comprising about 50% by weight of Copper and about 50% by weight of Chromium, said annular region having a height in the range of about 3mm to 6mm from the operative top of said electrical contact; and a petal region of said contact being made up of a composition comprising about 75% by weight of Copper and about 25% by weight of Chromium.