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US4530669A
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Method of making a borided dispenser cathode
Assignee: US Philips Corp
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Filing: 1983-02-22
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Granted: 1985-07-23
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Expires: 2003-02-22
Abstract
Abstract A borided dispenser cathode of the type including a metallic base material is made by cleaning the cathode by annealing it in a hydrogen-containing atmosphere, depositing boron on the cathode by heating the cathode in an atmosphere containing a gaseous boron compound, and forming a boride of the metallic base material by heating the cathode to its operating temperature in a non-reactive atmosphere and maintaining the temperature for a time period sufficient to enable deposited boron to combine with the metallic base material.
Inventors
- 👤 Georg Gartner
- 👤 Egbert B. G. W. Gotje
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:27
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/04; H01J9/042; H01J23/00; H01J23/02; H01J23/04; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/28
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
129 words
A method of making a borided dispenser cathode of the type comprising a metallic base material containing a metal oxide emissive material which continuously diffuses to the cathode surface during operation, said metallic base material being capable of forming a boride compound when exposed to boron at the cathode's operating temperature, said method comprising the steps of: (a) cleaning the cathode by annealing it in a hydrogen-containing atmosphere; (b) depositing boron on the cathode by heating the cathode in an atmosphere containing a gaseous boron compound; and (c) forming a boride of the metallic base material by heating the cathode to its operating temperature in a nonreactive atmosphere and maintaining said temperature for a time period sufficient to effect the reaction of deposited boron with the metallic base material.
Claim 2
Independent Claim
129 words
A method of making a borided dispenser cathode of the type comprising a metallic base material containing a metal oxide emissive material which continuously diffuses to the cathode surface during operation, said metallic base material being capable of forming a boride compound when exposed to boron at the cathode's operating temperature, said method comprising the steps of: (a) cleaning the cathode by annealing it in a hydrogen-containing atmosphere; (b) depositing boron on the cathode by heating the cathode in an atmosphere containing a gaseous boron compound; and (c) forming a boride of the metallic base material by heating the cathode to its operating temperature in a nonreactive atmosphere and maintaining said temperature for a time period sufficient to effect the reaction of deposited boron with the metallic base material.
Claim 3
Dependent Claim
18 words
A method as in claim 1 where the gaseous boron compound is diborane (B 2 H 6 ).
Claim 4
Dependent Claim
21 words
A method as in claim 1 or 2 where the metallic base material is roughened prior to performing the cleaning step.
Claim 5
Dependent Claim
29 words
A method as in claim 1 or 2 where the emissive material consists essentially of an oxide of one of the metals of group III-B of the periodic table.
Claim 6
Dependent Claim
23 words
A method as in claim 4 where the emissive material consists essentially of thorium-oxide and where the base material consists essentially of tungsten.
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) | 1988-07-22 | 1989-01-21 | 1989-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-22 | 1993-01-21 | 1993-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-22 | 1997-01-21 | 1997-07-23 | $7700.00 | Window Closed / Lapsed |