US4313854A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oxide-coated cathode for electron tube
Assignee: Hitachi Ltd
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Filing: 1979-11-06
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Granted: 1982-02-02
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Expires: 1999-11-06
Abstract
Abstract An oxide-coated cathode for electron tubes comprising a base metal plate made of an alloy containing nickel as a major component and at least one high-melting point metal in an amount of 2% by weight or more, and if required, a small amount of one or more reducing elements, and an electron emissive alkaline earth metal oxide layer adhered to the base metal plate, characterized by having a carbide layer made of at least one carbide of Si, B, Ti, Zr, Hf, V, Nb, Ta, Mo or W between the base metal plate and the electron emissive alkaline earth metal oxide layer can maintain electron emitting life for a long period of time due to the prevention of interfacial reaction between the base metal layer and the alkaline earth metal oxide layer.
Inventors
- 👤 Kazuo Sunahara
- 👤 Akira Misumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:31
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/14
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
123 words
In an oxide-coated cathode for electron tubes comprising a base metal plate made of an alloy containing nickel as a major component and at least one high-melting point metal in an amount of 2% by weight or more, and an electron emissive alkaline earth metal oxide layer adhered to the base metal plate, the improvement which comprises having a carbide layer made of at least one carbide of Si, B, Ti, Zr, Hf, V, Nb, Ta, Mo or W between the base metal plate and the electron emissive alkaline earth metal oxide layer, said carbide layer having a thickness sufficient for repressing an interfacial reaction between the base metal plate and the alkaline earth oxide layer and being not more than 5000 A.
Claim 2
Dependent Claim
123 words
In an oxide-coated cathode for electron tubes comprising a base metal plate made of an alloy containing nickel as a major component and at least one high-melting point metal in an amount of 2% by weight or more, and an electron emissive alkaline earth metal oxide layer adhered to the base metal plate, the improvement which comprises having a carbide layer made of at least one carbide of Si, B, Ti, Zr, Hf, V, Nb, Ta, Mo or W between the base metal plate and the electron emissive alkaline earth metal oxide layer, said carbide layer having a thickness sufficient for repressing an interfacial reaction between the base metal plate and the alkaline earth oxide layer and being not more than 5000 A.
Claim 3
Dependent Claim
44 words
An oxide-coated cathode for electron tubes according to claim 1, wherein the base metal plate is made of an alloy that further contains at least one reducing element selected from the group consisting of Zr, Al, Mg, Si, Ti, U, Cr, Nb, and Th.
Claim 4
Dependent Claim
41 words
An oxide-coated cathode for electron tubes according to claim 1, wherein a layer formed from powder of a metal or an alloy selected from Ni, Ni-Co, Ni-W, Ni-Mo and Ni-Re is provided between the base metal plate and the carbide layer.
Claim 5
Dependent Claim
41 words
An oxide-coated cathode for electron tubes according to claim 2, wherein a layer formed from powder of a metal or an alloy selected from Ni, Ni-Co, Ni-W, Ni-Mo and Ni-Re is provided between the base metal plate and the carbide layer.
Claim 6
Dependent Claim
27 words
An oxide-coated cathode for electron tubes according to claim 1, 2, 3 or 4, wherein the thickness of carbide layer is in the range of 50-5,000 A.
Claim 7
Dependent Claim
27 words
An oxide-coated cathode for electron tubes according to claim 1, 2, 3 or 4, wherein the thickness of carbide layer is in the range of 100-1,000 A.
Claim 8
Dependent Claim
24 words
An oxide-coated cathode for electron tubes according to claim 1, 2, 3 or 4, wherein said carbide layer is a ZrC or TiC layer.
Claim 9
Dependent Claim
21 words
An oxide-coated cathode for electron tubes according to claim 1, wherein said high-melting point metal is W, Mo, Re, or Ta.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-02-01 | 1985-08-03 | 1986-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-01 | 1989-08-03 | 1990-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-01 | 1993-08-03 | 1994-02-02 | $7700.00 | Window Closed / Lapsed |