US2548164A - Electrical contact - Google Patents
Electrical contact Download PDFInfo
- Publication number
- US2548164A US2548164A US788526A US78852647A US2548164A US 2548164 A US2548164 A US 2548164A US 788526 A US788526 A US 788526A US 78852647 A US78852647 A US 78852647A US 2548164 A US2548164 A US 2548164A
- Authority
- US
- United States
- Prior art keywords
- silver
- contacts
- germanium
- alloy
- electrical contact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000010946 fine silver Substances 0.000 claims description 21
- 229910052732 germanium Inorganic materials 0.000 claims description 18
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 16
- 239000000956 alloy Substances 0.000 description 15
- 229910045601 alloy Inorganic materials 0.000 description 15
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 10
- 229910052709 silver Inorganic materials 0.000 description 10
- 239000004332 silver Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 8
- 238000007792 addition Methods 0.000 description 4
- 229910000927 Ge alloy Inorganic materials 0.000 description 3
- BPYMJIZUWGOKJS-UHFFFAOYSA-N [Ge].[Ag] Chemical compound [Ge].[Ag] BPYMJIZUWGOKJS-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910001316 Ag alloy Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000005494 tarnishing Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
- H01H1/021—Composite material
- H01H1/023—Composite material having a noble metal as the basic material
Definitions
- This invention relates to electrical contacts, particularly contacts adapted to replace contacts formed. of fine silver.
- Silver is one of the most widely used electrical contact materials because of its high heat conductivity and high electrical conductivity.
- the rate of oxidation of silver is relatively low as .compared to other materials of high heat and electrical conductivities, and this characteristic also accounts for its wide use in the electrical contact art.
- the contact resistance of contacts formed of silver remains low because any oxide which may be formed on the contact face is decomposed at relatively low temperatures.
- Fine silver as generally employed in the electrical contact art consists of at least 99.9% silver, the balance being principally copper. Many applications require that the contact material operate in or make and break a circuit carrying currents higher than the normal current permissible with fine silver or under mechanical conditions such that welding of the contacts is frequently encountered. Various silver alloys and other alloys and compositions have been employed in such instances.
- One of the objects of this invention is to provide electrical contacts having a higher current carrying ability than the usual electrical contacts formed of fine silver.
- Another object of this invention is to improve the electrical contact characteristics of fine silver.
- Fig. 1 of the drawing illustrates an electrical contact with a disc of silver-germanium alloy.
- Fig. 2 of the drawing is a graph illustrating the no weld current for contacts formed of fine silver and contacts made in accordance with the present invention.
- the present invention contemplates the production of contacts formed of silver to which has been added a small amount or small proportion of germanium.
- the silver-germanium alloy for such contacts may be formed of the usual silver of commerse which contains small amounts of other elements or metals.
- the alloy may be formed in any desired manner.
- a convenient method for the formation of this alloy consists in forming a pre-alloy consisting of relatively large amounts or proportions of germanium.
- the desired silver-germanium alloy for use in forming the contacts may then be produced by adding an amount of the pro-alloy sufficient to 2 produce a final alloy havingthe desired composition.
- the alloy may also be made by powder metallurgy methods.
- electrical contacts formed of silver and fine silver containing up to about 0.25% germanium exhibit superior electrical contact characteristics as compared to those formedof fine silver.
- the preferred alloy for electrical contact purposes contains from about 0.06% to about 0.23% germanium.
- Electrical contacts may be formed of these alloys by any desired method such as melting and casting, punching disks from sheets or by forming the contacts from rod or wire.
- the graph illustrates diagrammatically the substantial improvement in the electrical contact characteristics obtained by the addition of these small amounts of germanium to fine silver.
- the no weld current for electrical contacts is obtained by placing the contacts in an electrical circuit including a resistive load and making and a breaking the circuit 100,000 cycles. The number of welds for a pair of contacts of a single material or alloy is noted while the current is maintained constant for this number of cycles. Additional tests are conducted at other currents in like manner. The number of welds obtained in the different tests are plotted against the current flowing in the circuit.
- the no weld current is obtained by interpolating the curve for each material to extend the curve to zero number of welds. The point at which the curve intersects the zero weld line indicates the maximum current which contacts formed of that particular material or alloy may carry without a welding and sticking of the contacts in 100,000 cycles.
- germanium as contemplated by the present invention does not adversely affect the contact resistance nor the conductivity of the silver.
- the presence of the germanium does decrease somewhat the resistance of the silver to tarnishing and oxidation. It has also been discovered that the presence of these small amounts of ger manium reduce the transfer of the contact material.
Description
April 10, 1951 1J. D. KLEIS 2,548,164
ELECTRICAL CONTACT Filed Nov. 28, 1947 Conzacz Disc of S2! ver- Germ an /'um I fill oy 4 W 0.05 0./0 0J5 0.20 0.25 Fine PER CENT GERMAN/UM Silver JOHN 0. M95
INVENTOR.
BYA %M Patented Apr. 10, 1951 ELECTRICAL CONTACT 7 John D. Kleis, Lake Forest, 111., assignor to Fansteel Metallurgical Corporation,
North Chicago,
111., a corporationof New York Application November 28, 1947, Serial No. 788,526
2 Claims. (Cl. 75-173) This invention relates to electrical contacts, particularly contacts adapted to replace contacts formed. of fine silver.
Silver is one of the most widely used electrical contact materials because of its high heat conductivity and high electrical conductivity. The rate of oxidation of silver is relatively low as .compared to other materials of high heat and electrical conductivities, and this characteristic also accounts for its wide use in the electrical contact art. The contact resistance of contacts formed of silver remains low because any oxide which may be formed on the contact face is decomposed at relatively low temperatures.
Fine silver as generally employed in the electrical contact art consists of at least 99.9% silver, the balance being principally copper. Many applications require that the contact material operate in or make and break a circuit carrying currents higher than the normal current permissible with fine silver or under mechanical conditions such that welding of the contacts is frequently encountered. Various silver alloys and other alloys and compositions have been employed in such instances.
One of the objects of this invention is to provide electrical contacts having a higher current carrying ability than the usual electrical contacts formed of fine silver.
Another object of this invention is to improve the electrical contact characteristics of fine silver.
Other objects and advantages of this invention will become apparent from a consideration of the description and claims which follow.
Fig. 1 of the drawing illustrates an electrical contact with a disc of silver-germanium alloy.
Fig. 2 of the drawing is a graph illustrating the no weld current for contacts formed of fine silver and contacts made in accordance with the present invention.
The present invention contemplates the production of contacts formed of silver to which has been added a small amount or small proportion of germanium. The silver-germanium alloy for such contacts may be formed of the usual silver of commerse which contains small amounts of other elements or metals. The alloy may be formed in any desired manner. A convenient method for the formation of this alloy consists in forming a pre-alloy consisting of relatively large amounts or proportions of germanium. The desired silver-germanium alloy for use in forming the contacts may then be produced by adding an amount of the pro-alloy sufficient to 2 produce a final alloy havingthe desired composition. vThe alloy may also be made by powder metallurgy methods.
I have discovered that electrical contacts formed of silver and fine silver containing up to about 0.25% germanium exhibit superior electrical contact characteristics as compared to those formedof fine silver. The preferred alloy for electrical contact purposes contains from about 0.06% to about 0.23% germanium.
Electrical contacts may be formed of these alloys by any desired method such as melting and casting, punching disks from sheets or by forming the contacts from rod or wire.
The graph illustrates diagrammatically the substantial improvement in the electrical contact characteristics obtained by the addition of these small amounts of germanium to fine silver. The no weld current for electrical contacts is obtained by placing the contacts in an electrical circuit including a resistive load and making and a breaking the circuit 100,000 cycles. The number of welds for a pair of contacts of a single material or alloy is noted while the current is maintained constant for this number of cycles. Additional tests are conducted at other currents in like manner. The number of welds obtained in the different tests are plotted against the current flowing in the circuit. The no weld current is obtained by interpolating the curve for each material to extend the curve to zero number of welds. The point at which the curve intersects the zero weld line indicates the maximum current which contacts formed of that particular material or alloy may carry without a welding and sticking of the contacts in 100,000 cycles. I
From a series of such experimental tests the following results were obtained:
Contact Material 3glg l lmperes Fine Silver 24 Fine Silver+0.065% Ge 28 Fine Silver+0.l0% Gc 32. 5
Fine Silver+0.20% Ge Fine Silver+0.23+ Ge.-- Fine Silvcr+l.0% Ge 0.17%. The current carrying ability then decreases very rapidly so that the no weld current for contacts formed of fine silver containing approximately 0.25% is substantially the same as that for contacts formed of fine silver. Further additions of germanium decrease the current carrying ability.
The addition of the small amounts of germanium as contemplated by the present invention does not adversely affect the contact resistance nor the conductivity of the silver. The presence of the germanium does decrease somewhat the resistance of the silver to tarnishing and oxidation. It has also been discovered that the presence of these small amounts of ger manium reduce the transfer of the contact material.
Contacts formed of silver alloys containing small amounts of other metals are also improved by the addition of the small amounts of germanium contemplated by the present invention.
1. An electrical contact formed of an alloy composed of fine silver and germanium, the germanium constituting up to 0.23% of the alloy, the contact being characterized by having a no weld current characteristic in excess of the no weld current characteristic of contacts formed of fine silver.
2. An electrical contact formed of an alloy composed of fine silver and germanium, the germanium constituting from 0.06% to 0.23% 01' the alloy.
JOHN D. KLEIS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,154,068 Ellis Apr. 11, 1939 2,221,285 Hensel et al Nov. 12, 1940 FOREIGN PATENTS Number Country Date 681,980 Germany Oct. 4, 1939 OTHER REFERENCES
Claims (1)
1. AN ELECTRICAL CONTACT FORMED OF AN ALLOY COMPOSED OF FINE SILVER AND GERMANIUM, THE GERMANIUM CONSTITUTING UP TO 0.23% OF THE ALLOY, THE CONTACT BEING CHARACTERIZED BY HAVING A "NO WELD" CURRENT CHARACTERISTIC IN EXCESS OF THE "NO WELD" CURRENT CHARACTERISTIC OF CONTACTS FORMED OF FINE SILVER.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US788526A US2548164A (en) | 1947-11-28 | 1947-11-28 | Electrical contact |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US788526A US2548164A (en) | 1947-11-28 | 1947-11-28 | Electrical contact |
Publications (1)
Publication Number | Publication Date |
---|---|
US2548164A true US2548164A (en) | 1951-04-10 |
Family
ID=25144761
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US788526A Expired - Lifetime US2548164A (en) | 1947-11-28 | 1947-11-28 | Electrical contact |
Country Status (1)
Country | Link |
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US (1) | US2548164A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3451808A (en) * | 1966-12-06 | 1969-06-24 | Isabellen Hutte Heusler Kg | Copper-manganese alloys and articles made therefrom |
DE2924238A1 (en) * | 1978-06-16 | 1979-12-20 | Nippon Telegraph & Telephone | ELECTRICAL CONTACT MATERIAL AND METHOD OF ITS MANUFACTURING |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2154068A (en) * | 1938-04-30 | 1939-04-11 | Bell Telephone Labor Inc | Electrical contact |
DE681980C (en) * | 1938-01-22 | 1939-10-05 | I G Farbenindustrie Akt Ges | Process for the preparation of 4-amino-2-oxyquinolines |
US2221285A (en) * | 1940-03-21 | 1940-11-12 | Mallory & Co Inc P R | Silver alloy |
-
1947
- 1947-11-28 US US788526A patent/US2548164A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE681980C (en) * | 1938-01-22 | 1939-10-05 | I G Farbenindustrie Akt Ges | Process for the preparation of 4-amino-2-oxyquinolines |
US2154068A (en) * | 1938-04-30 | 1939-04-11 | Bell Telephone Labor Inc | Electrical contact |
US2221285A (en) * | 1940-03-21 | 1940-11-12 | Mallory & Co Inc P R | Silver alloy |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3451808A (en) * | 1966-12-06 | 1969-06-24 | Isabellen Hutte Heusler Kg | Copper-manganese alloys and articles made therefrom |
DE2924238A1 (en) * | 1978-06-16 | 1979-12-20 | Nippon Telegraph & Telephone | ELECTRICAL CONTACT MATERIAL AND METHOD OF ITS MANUFACTURING |
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