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US4452677A
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Tungsten-quartz seals
Assignee: Osram Sylvania Inc
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Filing: 1983-02-02
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Granted: 1984-06-05
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Expires: 2003-02-02
Abstract
Abstract Tungsten-to-quartz seals are improved by electrochemically etching drawn, ground tungsten rod until some of the original draw lines appear and then using the so treated rod in the seal formation. The etching is carried out in a solution of NaNO 2 ; NaOH; and H 2 O.
Inventors
- 👤 Donald A. Richardson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:00
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/24; H01J9/32; H01J9/323; C; C25; C25F; C25F3/00; C25F3/02; C25F3/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
64 words
In the method of reducing cracks in hermetic seals formed between drawn, ground tungsten rod and quartz, the improvement comprising the steps of: electrochemically etching said tungsten rod in an etching solution until some of the original draw lines appear; stopping said etching; removing said tungsten rod from said etching solution; and subsequently sealing said tungsten rod in quartz to form said hermetic seal.
Claim 2
Dependent Claim
64 words
In the method of reducing cracks in hermetic seals formed between drawn, ground tungsten rod and quartz, the improvement comprising the steps of: electrochemically etching said tungsten rod in an etching solution until some of the original draw lines appear; stopping said etching; removing said tungsten rod from said etching solution; and subsequently sealing said tungsten rod in quartz to form said hermetic seal.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said electrochemical etching takes place in a solution of NaNO 2 , NaOH, and H 2 O.
Claim 4
Dependent Claim
28 words
The method of claim 2 wherein said solution comprises, by volume, about 10 parts water, about 1 part NaOH, and said solution is saturated with NaNO 2 .
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) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |