US4716081A
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Conductive compositions and conductive powders for use therein
Assignee: ERCON Inc 26 EMERSON ROAD WALTHAM MA 02154 A CORP OF
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Filing: 1985-07-19
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Granted: 1987-12-29
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Expires: 2005-07-19
Abstract
Abstract An improved silver-coated copper-based powder which is characterized by extraordinary stability, in terms of electroconductivity, when the powder is utilized with organic resin to form electroconductive compositions. The powder is made by subjecting it to an intensive heat treatment after the silver is coated thereon.
Inventors
- 👤 John E. Ehrreich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:08
CPC Classifications
H; H01; H01B; H01B1/00; H01B1/02; H01B1/026; B; B22; B22F; B22F1/00; B22F1/17; C; C22; C22C; C22C5/00; C22C5/06; H01B1/20; H01B1/22; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
93 words
A process of making an electrically conductive metal powder of average particle dimension of less than 0.025 inch comprising cleaning copper powder in a metal-complexing cleaning bath to form a clean powder, therupon plating the surface of the resultant clean powder with a silver coating in a plating solution, while maintaining continuous agitation of said plating solution, rinsing, drying, and then heat treating said powder at a temperature of at least about 130° C. for a period of time effective to enhance its heat-aging stability when loaded into an organic polymer resin matrix.
Claim 2
Dependent Claim
93 words
A process of making an electrically conductive metal powder of average particle dimension of less than 0.025 inch comprising cleaning copper powder in a metal-complexing cleaning bath to form a clean powder, therupon plating the surface of the resultant clean powder with a silver coating in a plating solution, while maintaining continuous agitation of said plating solution, rinsing, drying, and then heat treating said powder at a temperature of at least about 130° C. for a period of time effective to enhance its heat-aging stability when loaded into an organic polymer resin matrix.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein said complexing agent is cyanide ion.
Claim 4
Dependent Claim
17 words
The process of claim 2 wherein said cyanide ion is obtained from sodium cyanide or potassium cyanide.
Claim 5
Dependent Claim
40 words
A process as defined in claim 1 wherein said heat-treating said electrically conductive powder, after said plating step, takes place at a temperature of from about 130° C. to 210° C. for a period of time greater than 24 hours.
Claim 6
Dependent Claim
16 words
A process as defined in claim 2 wherein said organic polymer resin is a silicone resin.
Claim 7
Dependent Claim
32 words
A process as defined in claim 4 wherein said heat treating is carried out at a temperature of at least about 130° C. for a period of at least about 70 hours.
Claim 8
Dependent Claim
13 words
The process of claim 2 wherein said copper powder is substantially pure copper.
Claim 9
Dependent Claim
22 words
The process of claim 1 wherein said replacement plating is carried out in a plating bath of silver nitrate or silver cyanide.
Claim 10
Dependent Claim
21 words
The process of claim 2 wherein said plating is carried out in a plating bath of silver nitrate or silver cyanide.
Claim 11
Dependent Claim
22 words
The process of claim 3 wherein said replacement plating is carried out in a plating bath of silver nitrate or silver cyanide.
Claim 12
Dependent Claim
19 words
A process as defined in claim 4 wherein said copper powder has an average particle size below 0.010 inch.
Claim 13
Dependent Claim
47 words
A process as defined in claim 1 wherein said heat-aging stability of said metal powder is manifested by the characteristic of maintaining a volume resistivity of less than 2 ohm-cm after being subjected to an age test at 195° C. for 500 hours in the Standard Test.
Claim 14
Dependent Claim
20 words
A process as defined in claim 12 wherein said volume resistivity is maintained for 1000 hours in a Standard Test.
Claim 15
Dependent Claim
47 words
A process as defined in claim 4 wherein said heat-aging stability of said metal powder is manifested by the characteristic of maintaining a volume resistivity of less than 2 ohm-cm after being subjected to an age test at 195° C. for 500 hours in the Standard Test.
Claim 16
Dependent Claim
47 words
A process as defined in claim 6 wherein said heat-aging stability of said metal powder is manifested by the characteristic of maintaining a volume resistivity of less than 2 ohm-cm after being subjected to an age test at 195° C. for 500 hours in the Standard Test.
Claim 17
Dependent Claim
39 words
A process as defined in claim 1 wherein said heat aging stability is manifested by an increase in volume resistivity of less than a factor of 100 in the first 100 hours at 195° C. in the Standard Test.
Claim 18
Dependent Claim
38 words
A process as defined in claim 4 wherein said heat aging stability is characterized by an inrease in volume resistivity of less than a factor of 100 in the first 100 hours at 195° in the Standard Test.
Claim 19
Dependent Claim
79 words
A process of making an improved electrically conductive metal powder of average particle dimension of less than about 0.025 inch comprising a coating of silver on a copper core by heat-treating said powder, for a period of time effective to enhance its heat-aging stability, as measured by Standard Test, such that the resistivity of said formation in said Test increases to less than 2 ohm-cm after being subjected to the Standard Test at at 195° C. for 500 hours.
Claim 20
Dependent Claim
79 words
A process of making an improved electrically conductive metal powder of average particle dimension of less than about 0.025 inch comprising a coating of silver on a copper core by heat-treating said powder, for a period of time effective to enhance its heat-aging stability, as measured by Standard Test, such that the resistivity of said formation in said Test increases to less than 2 ohm-cm after being subjected to the Standard Test at at 195° C. for 500 hours.
Claim 21
Dependent Claim
18 words
A process as defined in claim 18 wherein said heat-treating is carried out at temperatures above 130° C.
Claim 22
Dependent Claim
20 words
A process as defined in claim 18 wherein said powder has an average particle diameter of less than 0.010 inch.
Claim 23
Dependent Claim
26 words
A process as defined in claim 18 wherein said silver coating is derived from silver ions of a salt selected from silver cyanide and silver nitrate.
Claim 24
Dependent Claim
74 words
An electrically conductive metal powder formed of a copper core with a continuous, thin, adherent silver coating thereover said powder being characterized by a heat-aging stability which is manifested by the characteristic of the Standard Test, whereby said powder in particle-to-particle contact, within test composition provides means to maintain a volume resistivity of less than 2 ohm-cm in said Test matrix after being subjected to an age test at 195° C. for 500 hours.
Claim 25
Dependent Claim
74 words
An electrically conductive metal powder formed of a copper core with a continuous, thin, adherent silver coating thereover said powder being characterized by a heat-aging stability which is manifested by the characteristic of the Standard Test, whereby said powder in particle-to-particle contact, within test composition provides means to maintain a volume resistivity of less than 2 ohm-cm in said Test matrix after being subjected to an age test at 195° C. for 500 hours.
Claim 26
Dependent Claim
24 words
A powder as defined in claim 22 wherein said volume resistivity of said Standard Test of is maintained for 1000 hours at 195° C.
Claim 27
Dependent Claim
29 words
A powder as defined in claim 22 wherein said copper core is substantially pure copper and said copper powder has an average particle diameter of less than 0.025 inches.
Claim 28
Dependent Claim
20 words
A powder as defined in claim 23 wherein said copper powder has an average particle diameter of below 0.010 inches.
Claim 29
Dependent Claim
54 words
A powder as defined in claim 25 wherein said heat-aging stability of said metal powder is manifested by the characteristic of said powder maintaining a volume resistivity of less than 2 ohm-cm when loaded into the Standard Test in particle-to-particle contact and being subjected to an age test at 195° C. for 500 hours.
Claim 30
Dependent Claim
42 words
A powder as defined in claim 22 wherein said heat aging stability of said powder, when loaded in particle-to-particle contact in said Standard Test manifests an increase in volume resistivity of a factor of 100 times in 500 hours at 195° C.
Claim 31
Dependent Claim
40 words
A powder as defined in claim 27 wherein said heat aging stability of said powder, when loaded in particle-to-particle contact in said Standard Test manifests an increase in volume resistivity of less than 100% in 500 hours at 195° C.
Claim 32
Dependent Claim
21 words
A powder as defined in claim 22 comprising from about 0.5 to 4 troy ounces of silver per pound of copper.
Claim 33
Dependent Claim
21 words
A powder as defined in claim 25 comprising from about 0.5 to 4 troy ounces of silver per pound of copper.
Claim 34
Dependent Claim
48 words
A process of making an improved electrically conductive metal powder of average particle dimension of less than about 0.025 inch comprising of a coating of silver on a copper core by heat treating said powder at a temperature of 130° to 210° C. for more than 24 hours.
Claim 35
Dependent Claim
48 words
A process of making an improved electrically conductive metal powder of average particle dimension of less than about 0.025 inch comprising of a coating of silver on a copper core by heat treating said powder at a temperature of 130° to 210° C. for more than 24 hours.
Claim 36
Dependent Claim
39 words
A process of making an improved electrically conductive metal powder of the type comprising a coating of silver on a copper core by heating said powder at a temperature of 130° to 210° C. for more than 70 hours.
Claim 37
Dependent Claim
39 words
A process of making an improved electrically conductive metal powder of the type comprising a coating of silver on a copper core by heating said powder at a temperature of 130° to 210° C. for more than 70 hours.
Claim 38
Dependent Claim
38 words
A process as defined in claim 31 wherein the amount of copper is 0.5 to 4 troy ounces per pound of silver, and wherein the average particle size of the powder is less than 0.010 inch in diameter.
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) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |