Patent US4011052A successfully refreshed from Google Patents.
US4011052A
Expired / Lapsed
US
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Electrical contact material and process
Assignee: Schneider Electric USA Inc
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Filing: 1975-10-08
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Granted: 1977-03-08
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Expires: 1995-10-08
Abstract
Abstract A material for use in making electrical contacts is produced in a powder form suitable for later processing into electrical contacts by standard metallurgical techniques. The material consists of a first metal, such as silver, and the oxide of a second metal, such as cadmium, added to the first metal in a proportion up to the limits of solubility of the second metal in the first metal. An oxide of a third metal having a low electronic work function level, such as lithium oxide, is added and uniformly distributed on the surfaces of the powder particles by precipitation. A fourth metal, such as tellurium, that is insoluble in the first metal is also added to provide selected characteristics.
Inventors
- 👤 Terrence Ardern Davies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:31
CPC Classifications
H; H01; H01H; H01H1/00; H01H1/02; H01H1/021; H01H1/023; H01H1/0237; H01H1/02372; H01H1/02374; H01B; H01B1/00; H01B1/02
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
313 words
A process of improving material used in manufacturing electrical contacts for electrical power applications and made with a first starting material selected from a group essentially consisting of a first metal in powder form and reducible compounds of the first metal in powder form both having a selected maximum particle size, and with a second starting material selected from a group essentially consisting of a second metal in powder form, reducible compounds of the second metal in powder form, and mixtures of the second metal in powder form all having a selected maximum particle size with said second metal selected to be more readily oxidizable than the first metal under similar environmental conditions and added in an amount from a minimum effective amount up to the maximum limit of solubility of the second metal in the first metal by mixing the first and second starting materials together to obtain a mixture having a substantially even dispersion of the first and second starting materials; heating the mixture in a reducing atmosphere at a temperatue below the melting temperature of the alloy of the alloy of the first and second metals in the proportions present to alloy the first and second metals in a powder form; sieving the alloyed mixture to produce a selected maximum particle size; heating the sieved mixture in an oxidizing atmosphere at a temperature and under conditions selected to substantially completely oxidize the second metal and with said temperature below the melting temperature of the alloy of the first and second metals in the proportions present to thereby maintain the mixture in a powder form; and sieving the oxidized mixture to produce a selected maximum particle size, said process comprising: adding at a selected time during the process an oxide of a third metal selected from a group consisting of the metals in group IA and IIA of a periodic table.
Claim 2
Dependent Claim
313 words
A process of improving material used in manufacturing electrical contacts for electrical power applications and made with a first starting material selected from a group essentially consisting of a first metal in powder form and reducible compounds of the first metal in powder form both having a selected maximum particle size, and with a second starting material selected from a group essentially consisting of a second metal in powder form, reducible compounds of the second metal in powder form, and mixtures of the second metal in powder form all having a selected maximum particle size with said second metal selected to be more readily oxidizable than the first metal under similar environmental conditions and added in an amount from a minimum effective amount up to the maximum limit of solubility of the second metal in the first metal by mixing the first and second starting materials together to obtain a mixture having a substantially even dispersion of the first and second starting materials; heating the mixture in a reducing atmosphere at a temperatue below the melting temperature of the alloy of the alloy of the first and second metals in the proportions present to alloy the first and second metals in a powder form; sieving the alloyed mixture to produce a selected maximum particle size; heating the sieved mixture in an oxidizing atmosphere at a temperature and under conditions selected to substantially completely oxidize the second metal and with said temperature below the melting temperature of the alloy of the first and second metals in the proportions present to thereby maintain the mixture in a powder form; and sieving the oxidized mixture to produce a selected maximum particle size, said process comprising: adding at a selected time during the process an oxide of a third metal selected from a group consisting of the metals in group IA and IIA of a periodic table.
Claim 3
Dependent Claim
20 words
A process according to claim 1 wherein the first metal is selected from a group consisting of silver and copper.
Claim 4
Dependent Claim
21 words
A process according to claim 2 wherein the second metal is selected from a group consisting of cadmium, zinc and tin.
Claim 5
Dependent Claim
52 words
A process according to claim 1 wherein the first metal is silver, the second metal is cadmium, and the temperature during the heating of the mixture in a reducing atmosphere is between 321° and 700° C and the temperature during the heating in an oxidizing atmosphere is between 400° and 600° C.
Claim 6
Dependent Claim
12 words
A process according to claim 4 wherein the third metal is lithium.
Claim 7
Dependent Claim
51 words
A process according to claim 1 wherein the first starting material is the first metal and the second starting material is a compound of the second metal reducable under selected conditions to an uncombined form; and the reducing atmosphere is selected to reduce the second metal compound to an uncombined form.
Claim 8
Dependent Claim
12 words
A process according to claim 6 wherein the first metal is silver.
Claim 9
Dependent Claim
29 words
A process according to claim 7 wherein the compound of the second metal is cadmium oxide and the temperature during heating to alloy is between 321° and 700° C.
Claim 10
Dependent Claim
21 words
A process according to claim 8 wherein the temperature of heating in an oxidizing atmosphere is between 400° and 600° C.
Claim 11
Dependent Claim
51 words
A process according to claim 6 wherein the oxide of the third metal is added as a third starting material to the mixture of the first and second starting materials with said third metal selected to be more readily oxidizable than the first and the second metals under similar environmental conditions.
Claim 12
Dependent Claim
20 words
A process according to claim 10 wherein the third metal is selected from the group consisting of lithium and barium.
Claim 13
Dependent Claim
18 words
A process according to claim 11 wherein the first metal is silver and the second metal is cadmium.
Claim 14
Dependent Claim
40 words
A process according to claim 12 wherein the third metal is lithium and the temperature during heating in a reducing atmosphere is between 321° and 700° C and the temperature for heating to oxidize is between 400° and 600° C.
Claim 15
Dependent Claim
94 words
A process according to claim 1 wherein the addition of the third metal comprises adding the third metal to the sieved mixture in a compound solution after sieving the oxidized mixture with said compound selected from a group consisting of those compounds of the selected third metal soluble in a suitable solvent and reducable under selected conditions to the oxide of the third metal, drying the solution, and reducing under the selected conditions at the selected time during said process the dried compound of the third metal to the oxide of the third metal.
Claim 16
Dependent Claim
12 words
A process according to claim 14 wherein the third metal is lithium.
Claim 17
Dependent Claim
72 words
A process according to claim 15 wherein the first starting material is silver, the second starting material is cadmium oxide, the third metal compound is a compound of lithium soluble in a selected solvent, and said adding of the solution comprises mixing the oxidized mixture and the solution in a slurry having a selected consistency and selected solution strength to obtain a selected proportion of the third metal in the contact material.
Claim 18
Dependent Claim
16 words
A process according to claim 16 wherein the compound of the third metal is lithium nitrate.
Claim 19
Dependent Claim
38 words
A process according to claim 17 wherein the solvent is propanol, the lithium nitrate is dissolved in the propanol and mixed in the selected proportion in a solution strength producing substantially equal amounts of solution and oxidized mixture.
Claim 20
Dependent Claim
50 words
A process according to claim 17 wherein said drying of the compound comprises heating the lithium nitrate solution and oxidized mixture after mixing to evaporate the propanol and dry the mixture and heating the dried mixture at a temperature of 700° C to reduce the lithium nitrate to lithium oxide.
Claim 21
Dependent Claim
57 words
A process according to claim 1 wherein the second starting material is a mixture of the second metal and a fourth metal selected to be insoluble in the first metal with said fourth metal selected to impart embrittlement qualities to the contact material and to be more readily oxidizable than the first metal under similar environmental conditions.
Claim 22
Dependent Claim
47 words
A process according to claim 20 wherein the second metal is cadmium and the fourth metal is tellurium and wherein said second starting material is produced by co-precipitation of cadmium and tellurium in a heating process to form an alloy of the oxides of cadmium and tellurium.
Claim 23
Dependent Claim
25 words
A process according to claim 21 wherein the first metal is silver and the temperature of heating to alloy is between 321° and 700° C.
Claim 24
Dependent Claim
80 words
A process according to claim 20 wherein the addition of the third metal comprises adding to the sieved oxidized mixture the third metal in the form of a compound of the third metal dissolved in a suitable solvent, mixing the dissolved compound in desired proportions with the sieved oxidized mixture, drying the compound, and reducing the compound to the oxide of the third metal at the selected time during the process to thereby add the oxide of the third metal.
Claim 25
Dependent Claim
12 words
A process according to claim 23 wherein the third metal is lithium.
Claim 26
Dependent Claim
18 words
A process according to claim 24 wherein the fourth metal is tellurium and the second metal is cadmium.
Claim 27
Dependent Claim
12 words
A process according to claim 25 wherein the first metal is silver.
Claim 28
Dependent Claim
18 words
A process according to claim 26 wherein said second metal is cadmium and said fourth metal is tellurium.
Claim 29
Dependent Claim
12 words
A process according to claim 27 wherein the third metal is lithium.
Claim 30
Dependent Claim
264 words
An electrical contact for electrical power level applications comprising a material produced by an improved process using a first starting material of a first metal in an uncombined or combined powder form having a maximum selected particle size and a second starting material of a second metal in an uncombined or combined powder form having a maximum selected particle size with said second metal selected to be more readily oxidizable than the first metal under similar environmental conditions added in an amount up to the maximum limits of solubility of the second metal in the first metal; mixing the first and second starting materials together to obtain a mixture having a substantially even dispersion of the two starting materials; heating the mixture in a reducing atmosphere at a temperature below the melting temperature of the alloy of the two metals in the proportions present to alloy the two metals in a powder form; sieving the alloyed mixture to produce a selected maximum particle size; heating the sieved mixture in an oxidizing atmosphere at a temperature and under conditions selected to substantially completely oxidize the second metal and with said temperature below the melting temperature of the alloy of the two metals in the proportions present to maintain the mixture in a powder form; and sieving the oxidized mixture to produce a powder having a maximum selected particle size, wherein said improved process comprises: adding at a selected time during the process an oxide of a third metal selected from a group consisting of the metals in groups IA and IIA of a periodic table.
Claim 31
Dependent Claim
264 words
An electrical contact for electrical power level applications comprising a material produced by an improved process using a first starting material of a first metal in an uncombined or combined powder form having a maximum selected particle size and a second starting material of a second metal in an uncombined or combined powder form having a maximum selected particle size with said second metal selected to be more readily oxidizable than the first metal under similar environmental conditions added in an amount up to the maximum limits of solubility of the second metal in the first metal; mixing the first and second starting materials together to obtain a mixture having a substantially even dispersion of the two starting materials; heating the mixture in a reducing atmosphere at a temperature below the melting temperature of the alloy of the two metals in the proportions present to alloy the two metals in a powder form; sieving the alloyed mixture to produce a selected maximum particle size; heating the sieved mixture in an oxidizing atmosphere at a temperature and under conditions selected to substantially completely oxidize the second metal and with said temperature below the melting temperature of the alloy of the two metals in the proportions present to maintain the mixture in a powder form; and sieving the oxidized mixture to produce a powder having a maximum selected particle size, wherein said improved process comprises: adding at a selected time during the process an oxide of a third metal selected from a group consisting of the metals in groups IA and IIA of a periodic table.
Claim 32
Dependent Claim
21 words
An electrical contact according to claim 29 wherein the first metal is selected from a group consisting of silver and copper.
Claim 33
Dependent Claim
22 words
An electrical contact according to claim 29 wherein the second metal is selected from a group consisting of cadmium, zinc and tin.
Claim 34
Dependent Claim
53 words
An electrical contact according to claim 29 wherein the first metal is silver, the second metal is cadmium, and the temperature during the heating of the mixture in a reducing atmosphere is between 321° and 700° C, and the temperature during the heating in an oxidizing atmosphere is between 400° and 600° C.
Claim 35
Dependent Claim
21 words
An electrical contact according to claim 32 wherein the third metal is selected from a group consisting of lithium and barium.
Claim 36
Dependent Claim
52 words
An electrical contact according to claim 29 wherein the first metal is selected from a group consisting of metals having a relatively high electrical conductivity, and the second metal is selected from a group of metals selected to be insoluble in the first metal and to impart embrittlement qualities to the contact.
Claim 37
Dependent Claim
13 words
An electrical contact according to claim 34 wherein the first metal is silver.
Claim 38
Dependent Claim
28 words
An electrical contact according to claim 34 wherein the second starting material is cadmium oxide and the temperature during heating to alloy is between 321° and 700° C.
Claim 39
Dependent Claim
22 words
An electrical contact according to claim 36 wherein the temperature of heating in an oxidizing atmosphere is between 400° and 600° C.
Claim 40
Dependent Claim
52 words
An electrical contact according to claim 34 wherein the oxide of the third metal is added as a third starting material to the mixture of the first and second starting materials with said third metal selected to be more readily oxidizable than the first and the second metals under similar environmental circumstances.
Claim 41
Dependent Claim
21 words
An electrical contact according to claim 38 wherein the third metal is selected from a group consisting of lithium and barium.
Claim 42
Dependent Claim
19 words
An electrical contact according to claim 39 wherein the first metal is silver and the second metal is cadmium.
Claim 43
Dependent Claim
41 words
An electrical contact according to claim 40 wherein the third metal is lithium and the temperature during heating in a reducing atmosphere is between 321° and 700° C and the temperature of heating to oxidize is between 400° and 600° C.
Claim 44
Dependent Claim
94 words
An electrical contact according to claim 29 wherein the addition of the oxide of the third metal comprises adding the third metal in the form of a compound in solution to the sieved mixture after sieving the oxidized mixture with said compound selected from a group consisting of those compounds of the third metal soluble in a selected solvent and reducible under selected conditions to the oxide of the third metal, drying the compound, and reducing the compound under the selected conditions during the process to thereby add the oxide of the third metal.
Claim 45
Dependent Claim
13 words
An electrical contact according to claim 42 wherein the third metal is lithium.
Claim 46
Dependent Claim
69 words
An electrical contact according to claim 43 wherein the first starting material is silver, the second starting material is cadmium oxide, the compound in solution is a compound of lithium in solution in a selected solvent, and said adding of the solution comprises mixing the oxidized mixture and the solution in a slurry in the desired proportions to obtain a selected amount of the third metal in the material.
Claim 47
Dependent Claim
17 words
An electrical contact according to claim 44 wherein the compound of the third metal is lithium nitrate.
Claim 48
Dependent Claim
42 words
An electrical contact according to claim 45 wherein the solvent is propanol, and the lithium nitrate is dissolved in the propanol and mixed in the selected proportion in a solution having a strength producing substantially equal amounts of solution and oxidized mixture.
Claim 49
Dependent Claim
51 words
An electrical contact according to claim 46 wherein said drying of the solution comprises heating the lithium nitrate solution and oxidized mixture after mixing to evaporate the propanol and dry the mixture, and heating the dried mixture at a temperature of 700° C to reduce the lithium nitrate to lithium oxide.
Claim 50
Dependent Claim
53 words
An electrical contact according to claim 29 wherein the second starting material consists essentially of the second metal combined with a fourth metal selected to be insoluble in the first metal, to impart embrittlement qualities to the contact material, and to be more readily oxidizable than the first metal under similar environmental conditions.
Claim 51
Dependent Claim
46 words
An electrical contact according to claim 48 wherein the second metal is cadmium and the fourth metal is tellurium with said second starting material produced by co-precipitation of cadmium and tellurium in a heating process to form an alloy of cadmium and tellurium and their oxides.
Claim 52
Dependent Claim
26 words
An electrical contact according to claim 49 wherein the first metal is silver and the temperature of heating to alloy is between 321° and 700° C.
Claim 53
Dependent Claim
74 words
An electrical contact according to claim 48 wherein the addition of the third metal comprises adding the third metal to the sieved oxidized mixture in the form of a compound of the third metal dissolved in a suitable solvent, mixing the resulting solution in desired proportions with the sieved oxidized mixture, drying the resulting solution, and heating the desired mixture under conditions selected to reduce the compound to the oxide of the third metal.
Claim 54
Dependent Claim
13 words
An electrical contact according to claim 51 wherein the third metal is lithium.
Claim 55
Dependent Claim
19 words
An electrical contact according to claim 52 wherein the fourth metal is tellurium and the second metal is cadmium.
Claim 56
Dependent Claim
13 words
An electrical contact according to claim 53 wherein the first metal is silver.
Claim 57
Dependent Claim
19 words
An electrical contact according to claim 51 wherein said second metal is cadmium and said fourth metal is tellurium.
Claim 58
Dependent Claim
13 words
An electrical contact according to claim 55 wherein the third metal is lithium.
Claim 59
Dependent Claim
13 words
An electrical contact according to claim 56 wherein the first metal is silver.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-07 | 1980-09-06 | 1981-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-07 | 1984-09-06 | 1985-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-07 | 1988-09-06 | 1989-03-08 | $7700.00 | Window Closed / Lapsed |