US3922236A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical contact materials
Assignee: Schneider Electric USA Inc
•
Filing: 1973-07-30
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Granted: 1975-11-25
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Expires: 1993-07-30
Abstract
Abstract An electrical contact material which consists of a mixture of silver, 5 to 50 weight percent of copper and 2 to 20 weight percent of lanthanum, strontium chromite of formula La1 xSrxCrO3, where the values of x lie between 0 and 1.0, formed as a hard, chemically inert, non-metallic phase of high electrical conductivity both within the bulk of, and at the surface of, the contact material. Methods of producing the electrical contact materials utilizing powder metallurgical techniques are outlined.
Inventors
- 👤 Peter Douglas
- 👤 David John Pedder
- 👤 Peter John Swallow
- 👤 Terrence Ardern Davies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:23
CPC Classifications
H; H01; H01H; H01H1/00; H01H1/02; H01H1/021; H01H1/023; Y; Y10; Y10S; Y10S75/00; Y10S75/95; Y10S75/951
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
67 words
An electrical contact material which consists of a mixture of silver, 5 to 50 weight percent of copper and 2 to 20 weight percent of lanthanum, strontium chromite of formula La1 xSrxCrO3, where the values of x lie between 0 and 1.0, formed as a hard, chemically inert, non-metallic phase of high electrical conductivity both within the bulk of, and at the surface of, the contact material.
Claim 2
Dependent Claim
67 words
An electrical contact material which consists of a mixture of silver, 5 to 50 weight percent of copper and 2 to 20 weight percent of lanthanum, strontium chromite of formula La1 xSrxCrO3, where the values of x lie between 0 and 1.0, formed as a hard, chemically inert, non-metallic phase of high electrical conductivity both within the bulk of, and at the surface of, the contact material.
Claim 3
Dependent Claim
70 words
AN ELECTRICAL CONTACT FORMED FROM A MATERIAL WHICH CONSISTS OF A MIXTURE OF SILVER, 5 TO 50 WEIGHT PERCENT OF COPPER AND 2 TO 20 WEIGHT PERCENT OF LANTHANUM, STRONTIUM CHROMITE OF FORMULA LA1-X SRXCRO3, WHERE THE VALUES OF X LIE BETWEEN 0 TO 1.0, FORMED AS A HARD, CHEMICALLY INERT, NONMETALLIC PHASE OF HIGH ELECTRICAL CONDUCTIVITY BOTH WITHIN THE BULK OF, AND AT THE SURFACE OF, THE CONTACT MATERIAL.
Claim 4
Dependent Claim
70 words
AN ELECTRICAL CONTACT FORMED FROM A MATERIAL WHICH CONSISTS OF A MIXTURE OF SILVER, 5 TO 50 WEIGHT PERCENT OF COPPER AND 2 TO 20 WEIGHT PERCENT OF LANTHANUM, STRONTIUM CHROMITE OF FORMULA LA1-X SRXCRO3, WHERE THE VALUES OF X LIE BETWEEN 0 TO 1.0, FORMED AS A HARD, CHEMICALLY INERT, NONMETALLIC PHASE OF HIGH ELECTRICAL CONDUCTIVITY BOTH WITHIN THE BULK OF, AND AT THE SURFACE OF, THE CONTACT MATERIAL.
Claim 5
Dependent Claim
18 words
An electrical contact material as claimed in claim 1 wherein the lanthanum, strontium chromite is of formula La0.7Sr0.3CrO3.
Claim 6
Dependent Claim
18 words
An electrical contact as claimed in claim 2 wherein the lanthanum, strontium chromite is of the formula La0.7Sr0.3CrO3.
Claim 7
Dependent Claim
18 words
An electrical contact material as claimed in claim 3 wherein the La0.7Sr0.3CrO3 content by weight is 5.0 percent.
Claim 8
Dependent Claim
17 words
An electrical contact as claimed in claim 4 wherein the La0.7Sr0.3CrO3 content by weight is 5.0 percent.
Claim 9
Dependent Claim
18 words
An electrical contact material as claimed in claim 5 wherein the copper content by weight is 5 percent.
Claim 10
Dependent Claim
17 words
An electrical contact as claimed in claim 6 wherein the copper content by weight is 5 percent.
Claim 11
Dependent Claim
18 words
An electrical contact material as claimed in claim 5 wherein the copper content by weight is 10 percent.
Claim 12
Dependent Claim
17 words
An electrical contact as claimed in claim 6 wherein the copper content by weight is 10 percent.
Claim 13
Independent Claim
114 words
A METHOD OF PRODUCING AN ELECTRICAL CONTACT MATERIAL INCLUDING THE STEPS OF PROVIDING IRREGULAR SILVER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 MESH; PROVIDING IRREGULAR COPPER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 MESH; PROVIDING LANTHANUM STRONTIUM CHROMITE POWDER OF FORMULA LA1-XSRXCRO3, WHERE THE VALUES LIE BETWEEN 0 AND 1.0, AND HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 10 MICRONS; MIXING THE POWDERS TOGETHER TO PROVIDE A FINE, EVENLY DISPERSED MIXTURE CONTAINING 5 TO 50 WEIGHT PERCENT OF COPPER, 2 TO 20 WEIGHT PERCENT OF LA1-XSRXCRO3 AND DESIRED SHAPE; AND SINTERING THE COMPACTED SHAPE. DESIRED SHAPE; AND SINTERING THE COMPACTED SHAPE.
Claim 14
Independent Claim
114 words
A METHOD OF PRODUCING AN ELECTRICAL CONTACT MATERIAL INCLUDING THE STEPS OF PROVIDING IRREGULAR SILVER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 MESH; PROVIDING IRREGULAR COPPER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 MESH; PROVIDING LANTHANUM STRONTIUM CHROMITE POWDER OF FORMULA LA1-XSRXCRO3, WHERE THE VALUES LIE BETWEEN 0 AND 1.0, AND HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 10 MICRONS; MIXING THE POWDERS TOGETHER TO PROVIDE A FINE, EVENLY DISPERSED MIXTURE CONTAINING 5 TO 50 WEIGHT PERCENT OF COPPER, 2 TO 20 WEIGHT PERCENT OF LA1-XSRXCRO3 AND DESIRED SHAPE; AND SINTERING THE COMPACTED SHAPE. DESIRED SHAPE; AND SINTERING THE COMPACTED SHAPE.
Claim 15
Dependent Claim
62 words
A method as claimed in claim 11 wherein the provision of the La1 x SrxCrO3 powder includes the steps of mixing La, Sr and Cr nitrates in stoichiometric proportions; spray decomposing the mixed nitrate solution to provide a mixed oxide powder; sintering the oxide powder in air; milling the sintered powder under acetone; and washing the milled powder in dilute hydrochloric acid.
Claim 16
Dependent Claim
16 words
A method as claimed in claim 11 wherein the lanthanum, strontium chromite is of formula La0.7Sr0.3CrO3.
Claim 17
Dependent Claim
16 words
A method as claimed in claim 12 wherein the lanthanum, strontium chromite is of formula La0.7Sr0.3CrO3.
Claim 18
Dependent Claim
27 words
A method as claimed in claim 14 wherein the sintering of the mixed oxide powder is effected for approximately 1/2 hour at a temperature of approximately 1,250*C.
Claim 19
Dependent Claim
19 words
A method as claimed in claim 14 wherein the milling of the sintered powder is effected for 96 hours.
Claim 20
Dependent Claim
37 words
A method as claimed in claim 13 wherein the sintering of the powder compact is effected in an atmosphere of 3% hydrogen/97% nitrogen gas mixture at a temperature of 750*C for a period of approximately 1 hour.
Claim 21
Dependent Claim
25 words
A method as claimed in claim 11 wherein the compacting of the powder is effected at a pressure of approximately 20 tons per square inch.
Claim 22
Dependent Claim
17 words
A method as claimed in claim 11 wherein the powder mixture is effected by dry tumble milling.
Claim 23
Dependent Claim
21 words
A method as claimed in claim 11 which includes the step of coining the sintered compacts to increase the density thereof.
Claim 24
Dependent Claim
22 words
A method as claimed in claim 20 wherein the coining is effected at a pressure of approximately 50 tons per square inch.
Claim 25
Dependent Claim
122 words
AN ELECTRICAL CONTACT MATERIAL PRODUCED BY A METHOD INCLUDING THE STEPS OF PROVIDING IRREGULAR SILVER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 BRITISH STANDARD MESH; PROVIDING IRREGULAR COPPER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 BRITISH STANDARD MESH; PROVIDING LANTHANUM STRONTIUM CHROMITE POWDER OF FORMULA LA1-XSRXCRO3, WHERE THE VALUES OF X LIE BETWEEN 0 AND 1.0, AND HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 10 MICRONS; MIXING THE POWDERS TOGETHER TO PROVIDE A FINE, EVENLY DISPERSED MIXTURE CONTAINING 5 TO 50 WEIGHT PERCENT OF COPPER, 2 TO 20 WEIGHT PERCENT OF LA1-XSRXCRO3 AND THE REMAINDER SILVER; COMPACTING THE POWDER MIXTURE INTO A DESIRED SHAPE; AND SINTERING THE COMPACTED SHAPE.
Claim 26
Dependent Claim
122 words
AN ELECTRICAL CONTACT MATERIAL PRODUCED BY A METHOD INCLUDING THE STEPS OF PROVIDING IRREGULAR SILVER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 BRITISH STANDARD MESH; PROVIDING IRREGULAR COPPER POWDER HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 350 BRITISH STANDARD MESH; PROVIDING LANTHANUM STRONTIUM CHROMITE POWDER OF FORMULA LA1-XSRXCRO3, WHERE THE VALUES OF X LIE BETWEEN 0 AND 1.0, AND HAVING A POWDER PARTICLE SIZE OF NOT GREATER THAN APPROXIMATELY 10 MICRONS; MIXING THE POWDERS TOGETHER TO PROVIDE A FINE, EVENLY DISPERSED MIXTURE CONTAINING 5 TO 50 WEIGHT PERCENT OF COPPER, 2 TO 20 WEIGHT PERCENT OF LA1-XSRXCRO3 AND THE REMAINDER SILVER; COMPACTING THE POWDER MIXTURE INTO A DESIRED SHAPE; AND SINTERING THE COMPACTED SHAPE.
Claim 27
Dependent Claim
67 words
An electrical contact material produced by the method as claimed in claim 22 wherein the provision of the La1 xSrxCrO3 powder includes the steps of mixing La, Sr and Cr nitrates in stoichiometric proportions; spray decomposing the mixed nitrate solution to provide a mixed oxide powder; sintering the oxide powder in air; milling the sintered powder under acetone; and washing the milled powder in dilute hydrochloric acid.
Claim 28
Dependent Claim
22 words
An electrical contact material produced by the method as claimed in claim 22 wherein the lanthanum, strontium chromite is of formula La0.7Sr0.3CrO3.
Claim 29
Dependent Claim
22 words
An electrical contact material produced by the method as claimed in claim 23 wherein the lanthanum, strontium chromite is of formula La0.7Sr0.3CrO3.
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) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |