US4199704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina, calcia, baria, strontia sealing composition and article of manufacture
Assignee: General Electric Co
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Filing: 1979-03-15
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Granted: 1980-04-22
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Expires: 1999-03-15
Abstract
Abstract An improved sealing composition for use between alumina ceramic parts, or between alumina ceramic and refractory metal, is based on 40 wt% Al 2 O 3 , 35 wt% CaO, 15 wt% BaO and 10 wt% SrO, and has an average thermal expansion coefficient of 95×10 -7 /°C. between 25° C. and 600° C. This composition after sealing achieves a closer match to the coefficient of thermal expansion of high density polycrystalline alumina (86×10 -7 /°C.) than previously available materials. In addition, it has a wider sealing range which facilitates seal processing.
Inventors
- 👤 Arun K. Varshneya
- 👤 William L. Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:29
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/12; C03C3/125; C03C8/00; C03C8/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
81 words
A sealing composition for use in bonding to alumina ceramic, said composition consisting essentially of the following constituent oxides within the indicated proportions by weight: Al 2 O 3 : 35 to 45% CaO: 25 to 40% BaO: 5 to 20% SrO: 8 to 30% and not over 4% in all of one or more of the following oxides for improving the wetting and flow characteristics: B 2 O 3 , MgO, SiO 2 , TiO 2 and ZrO 2 .
Claim 2
Dependent Claim
81 words
A sealing composition for use in bonding to alumina ceramic, said composition consisting essentially of the following constituent oxides within the indicated proportions by weight: Al 2 O 3 : 35 to 45% CaO: 25 to 40% BaO: 5 to 20% SrO: 8 to 30% and not over 4% in all of one or more of the following oxides for improving the wetting and flow characteristics: B 2 O 3 , MgO, SiO 2 , TiO 2 and ZrO 2 .
Claim 3
Dependent Claim
48 words
A sealing composition as in claim 1 wherein the proportions of the constituents have been selected to achieve in the glassy state of the composition over the temperature range from 25° C. to 600° C. an average thermal expansion coefficient between 90×10 -7 /°C. and 100×10 -7 /°C.
Claim 4
Dependent Claim
27 words
A sealing composition as in claim 1 wherein the proportions by weight are as follows: Al 2 O 3 40%, CaO 35%, BaO 15% and SrO 10%.
Claim 5
Dependent Claim
98 words
An article of manufacture comprising an alumina ceramic body having a part of ceramic or refractory metal bonded thereto by a sealant, said sealant being the end product of melting and congealing in place a composition consisting essentially of the following constituent oxides within the indicated proportions by weight: Al 2 O 3 : 35 to 45% CaO: 25 to 40% BaO: 5 to 20% SrO: 8 to 30% and not over 4% in all of one or more of the following oxides: B 2 O 3 , MgO, SiO 2 , TiO 2 and ZrO 2 .
Claim 6
Dependent Claim
98 words
An article of manufacture comprising an alumina ceramic body having a part of ceramic or refractory metal bonded thereto by a sealant, said sealant being the end product of melting and congealing in place a composition consisting essentially of the following constituent oxides within the indicated proportions by weight: Al 2 O 3 : 35 to 45% CaO: 25 to 40% BaO: 5 to 20% SrO: 8 to 30% and not over 4% in all of one or more of the following oxides: B 2 O 3 , MgO, SiO 2 , TiO 2 and ZrO 2 .
Claim 7
Dependent Claim
53 words
An article of manufacture as in claim 4 wherein the proportions of the constituents of the sealing composition have been selected to achieve in the glassy state of the composition over the temperature range from 25° C. to 600° C. an average thermal expansion coefficient between 90×10 -7 /°C. and 100×10 -7 /°C.
Claim 8
Dependent Claim
28 words
An article of manufacture as in claim 4 wherein the proportions by weight are as follows: Al 2 O 3 40%, CaO 35%, BaO 15% and SrO 10%.
Claim 9
Dependent Claim
121 words
A sealed electric lamp comprising an envelope formed of an alumina ceramic tube having end closures, a pair of electrodes and a filling of an ionizable medium therein, and a sealant bonding at least one end closure to said tube, wherein the improvement resides in said sealant being the end product of melting and congealing in place a composition consisting essentially of the following constituent oxides within the indicated proportions by weight: Al 2 O 3 : 35 to 45% CaO: 25 to 40% BaO: 5 to 20% SrO: 8 to 30% and not over 4% in all of one or more of the following oxides: B 2 O 3 , MgO, SiO 2 , TiO 2 and ZrO 2 .
Claim 10
Dependent Claim
121 words
A sealed electric lamp comprising an envelope formed of an alumina ceramic tube having end closures, a pair of electrodes and a filling of an ionizable medium therein, and a sealant bonding at least one end closure to said tube, wherein the improvement resides in said sealant being the end product of melting and congealing in place a composition consisting essentially of the following constituent oxides within the indicated proportions by weight: Al 2 O 3 : 35 to 45% CaO: 25 to 40% BaO: 5 to 20% SrO: 8 to 30% and not over 4% in all of one or more of the following oxides: B 2 O 3 , MgO, SiO 2 , TiO 2 and ZrO 2 .
Claim 11
Dependent Claim
53 words
A sealed electric lamp as in claim 7 wherein the proportions of the constituents of the sealing composition have been selected to achieve in the glassy state of the composition over the temperature range from 25° C. to 600° C. an average thermal expansion coefficient between 90×10 -7 /°C. and 100×10 -7 /°C.
Claim 12
Dependent Claim
28 words
A sealed electric lamp as in claim 7 wherein the proportions by weight are as follows: Al 2 O 3 40%, CaO 35%, BaO 35% and SrO 10%.
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) | 1983-04-22 | 1983-10-22 | 1984-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-22 | 1987-10-22 | 1988-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-22 | 1991-10-22 | 1992-04-22 | $7700.00 | Window Closed / Lapsed |