US4362564A
Expired / Lapsed
US
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Method for producing microporous metal bodies
Assignee: United States Department of Energy
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Filing: 1967-09-12
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Granted: 1982-12-07
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Expires: 1987-09-12
Abstract
Abstract Tungsten is vapor-deposited by hydrogen reduction of tungsten hexafluoride (WF 6 ) to produce a tungsten body having from 40 to 100 ppm fluorine. The tungsten is then heated under vacuum to produce grain boundary porosity for a sufficient period of time to allow the pores along the grain boundaries to become interconnected.
Inventors
- 👤 Joseph C. Danko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:17
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/56; B; B22; B22F; B22F3/00; B22F3/10; B22F3/11; B22F3/1143; G; G21; G21C; G21C3/00; G21C3/02; G21C3/04; G21C3/044; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
132 words
A process for producing a microporous tungsten body adapted for use as cladding for the emitter in a thermionic converter containing fissile fuel, and which functions to permit the flow of fission product gases, but prevents the release of fissile fuel particles outside the emitter cladding, comprising the steps of: vapor-depositing, to a thickness of about 0.020 to 0.040 inch, on a suitable support surface, impure tungsten having a fluorine content of from about 40 to 100 ppm by hydrogen reduction of tungsten hexafluoride (WF 6 ); removing the support surface from the deposited tungsten; and heating said impure vapor-deposited tungsten in a vacuum environment of about 10 -6 torr at a temperature of about 2500° C. for about 25 to 50 hours, so that grain boundary porosity occurs and becomes interconnected.
Claim 2
Dependent Claim
132 words
A process for producing a microporous tungsten body adapted for use as cladding for the emitter in a thermionic converter containing fissile fuel, and which functions to permit the flow of fission product gases, but prevents the release of fissile fuel particles outside the emitter cladding, comprising the steps of: vapor-depositing, to a thickness of about 0.020 to 0.040 inch, on a suitable support surface, impure tungsten having a fluorine content of from about 40 to 100 ppm by hydrogen reduction of tungsten hexafluoride (WF 6 ); removing the support surface from the deposited tungsten; and heating said impure vapor-deposited tungsten in a vacuum environment of about 10 -6 torr at a temperature of about 2500° C. for about 25 to 50 hours, so that grain boundary porosity occurs and becomes interconnected.
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) | 1985-12-06 | 1986-06-07 | 1986-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-06 | 1990-06-07 | 1990-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-06 | 1994-06-07 | 1994-12-07 | $7700.00 | Window Closed / Lapsed |