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US4005050A
Expired / Lapsed
US
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Tantalum or niobium-modified resistor element
Assignee: Federal Mogul Ignition LLC
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Filing: 1972-04-19
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Granted: 1977-01-25
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Expires: 1992-04-19
Abstract
Abstract An improved resistor element especially suitable for use in spark plugs is disclosed. The resistor element is prepared from a stannic oxide-barium, calcium or strontium borate composition doped with from 1 to 18 percent tantalum pentoxide or 1/2 to 5 percent niobium pentoxide based on the total batch weight. A method for producing the element is also disclosed.
Inventors
- 👤 Ronald K. Stewart
- 👤 Robert H. Insley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:50
CPC Classifications
H; H01; H01B; H01B1/00; H01B1/06; H01B1/08; C; C04; C04B; C04B35/00; C04B35/01; C04B35/453; C04B35/457; H01T; H01T13/00; H01T13/40; H01T13/41
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
202 words
A green ceramic article useful after firing as an electrical resistor element which is a modified stannic oxide semi-conductor, said article consisting essentially of stannic oxide, a modifying oxide selected from the group consisting of tantalum pentoxide, and niobium pentoxide, a barium, calcium or strontium compound, a boron compound and silica, the amount of said modifying oxide, based on the total weight of the article, when tantalum pentoxide, ranging from 1 to 18 percent by weight and, when niobium pentoxide, ranging from 1/2 to 5 percent by weight, the total barium, calcium or strontium content of the article, calculated as CaO, BaO, or SrO respectively, ranging from 1 to 26 percent by weight, the total boron content of the article, calculated as B 2 O 3 , ranging from 4 to 25 percent by weight, and the total silica, calculated as SiO 2 , ranging from 1/2 to 4 percent by weight wherein a plot of the resistance versus the amount of the modifying oxide present in the fired resistor has a positive slope as the tantalum pentoxide varies from 1 to 18 percent or as the niobium pentoxide varies from 1/2 to 5 percent by weight of the green ceramic article.
Claim 2
Dependent Claim
202 words
A green ceramic article useful after firing as an electrical resistor element which is a modified stannic oxide semi-conductor, said article consisting essentially of stannic oxide, a modifying oxide selected from the group consisting of tantalum pentoxide, and niobium pentoxide, a barium, calcium or strontium compound, a boron compound and silica, the amount of said modifying oxide, based on the total weight of the article, when tantalum pentoxide, ranging from 1 to 18 percent by weight and, when niobium pentoxide, ranging from 1/2 to 5 percent by weight, the total barium, calcium or strontium content of the article, calculated as CaO, BaO, or SrO respectively, ranging from 1 to 26 percent by weight, the total boron content of the article, calculated as B 2 O 3 , ranging from 4 to 25 percent by weight, and the total silica, calculated as SiO 2 , ranging from 1/2 to 4 percent by weight wherein a plot of the resistance versus the amount of the modifying oxide present in the fired resistor has a positive slope as the tantalum pentoxide varies from 1 to 18 percent or as the niobium pentoxide varies from 1/2 to 5 percent by weight of the green ceramic article.
Claim 3
Dependent Claim
106 words
A green ceramic article as claimed in claim 1 having an electrical resistance after firing of a desired value from 1000 to greater than 100,000 ohms depending on composition, said article consisting essentially of from a. 50 to 94 percent by weight SnO 2 , and b. 1 to 18 percent by weight Ta 2 O 5 , and c. 1 to 26 percent by weight BaO, CaO or SrO, and d. 4 to 25 percent by weight B 2 O 3 , and e. 1/2 to 4 percent by weight SiO 2 , and f. up to 10 percent by weight clay including said silica.
Claim 4
Dependent Claim
106 words
A green ceramic article as claimed in claim 1 having an electrical resistance after firing of a desired value from 1000 to greater than 100,000 ohms depending on composition, said article consisting essentially of from a. 50 to 94 percent by weight SnO 2 , and b. 1/2 to 5 percent by weight Nb 2 O 5 , and c. 1 to 26 percent by weight BaO, CaO or SrO, and d. 4 to 25 percent by weight B 2 O 3 , and e. 1/2 to 4 percent by weight SiO 2 , and f. up to 10 percent by weight clay including said silica.
Claim 5
Dependent Claim
72 words
A green ceramic article as claimed in claim 1 consisting essentially of from a. 60 to 75 percent by weight SnO 2 , and b. 1 to 14 percent by weight Ta 2 O 5 , and c. 12 to 13 percent by weight BaO, CaO or SrO, and d. 9 to 10 percent by weight B 2 O 3 , and e. up to 3 percent by weight SiO 2 .
Claim 6
Dependent Claim
71 words
A green ceramic article as claimed in claim 1 having an electrical resistance after firing of a desired value between 2000 and 6000 ohms, consisting of about a. 73.8 percent by weight SnO 2 , and b. 1.7 percent by weight Ta 2 O 5 , and c. 12.7 percent by weight BaO, and d. 9.6 percent by weight B 2 O 3 , and e. 2.2 percent SiO 2 .
Claim 7
Dependent Claim
71 words
A green ceramic article as claimed in claim 1 having an electrical resistance after firing of a desired value between 4000 and 12,000 ohms, consisting of about a. 71.2 percent by weight SnO 2 , and b. 4.3 percent by weight Ta 2 O 5 , and c. 12.7 percent by weight BaO, and d. 9.6 percent by weight B 2 O 3 , and e. 2.2 percent SiO 2 .
Claim 8
Independent Claim
197 words
A method for producing a sintered electrical resistor element, said method comprising the steps of preparing a batch which is a uniform mixture of finely divided particles, said batch consisting essentially of stannic oxide, a modifying oxide selected from the group consisting of tantalum pentoxide and niobium pentoxides, a barium, calcium or strontium compound, a boron compound and silica, the amount of said modifying oxide, based on the total weight of the batch, when tantalum pentoxide, ranging from 1 to 18 percent by weight and, when niobium pentoxide, ranging from 1/2 to 5 percent by weight, the total barium, calcium or strontium content, calculated as CaO, BaO or SrO respectively, ranging from 1 to 26 percent by weight, the total boron content of the batch, calculated as B 2 O 3 , ranging from 4 to 25 percent by weight, and up to 4 percent by weight silica, based upon the total weight of the batch, pressing a shape from the batch at a pressure of about 10,000 to 40,000 pounds per square inch, and firing the shape to a temperature within the range of about 2300°-2700° F. for a time sufficient to form said resistor element.
Claim 9
Independent Claim
197 words
A method for producing a sintered electrical resistor element, said method comprising the steps of preparing a batch which is a uniform mixture of finely divided particles, said batch consisting essentially of stannic oxide, a modifying oxide selected from the group consisting of tantalum pentoxide and niobium pentoxides, a barium, calcium or strontium compound, a boron compound and silica, the amount of said modifying oxide, based on the total weight of the batch, when tantalum pentoxide, ranging from 1 to 18 percent by weight and, when niobium pentoxide, ranging from 1/2 to 5 percent by weight, the total barium, calcium or strontium content, calculated as CaO, BaO or SrO respectively, ranging from 1 to 26 percent by weight, the total boron content of the batch, calculated as B 2 O 3 , ranging from 4 to 25 percent by weight, and up to 4 percent by weight silica, based upon the total weight of the batch, pressing a shape from the batch at a pressure of about 10,000 to 40,000 pounds per square inch, and firing the shape to a temperature within the range of about 2300°-2700° F. for a time sufficient to form said resistor element.
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) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |