US3630770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for fabricating lanthanum boride cathodes
Assignee: General Electric Co
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Filing: 1969-04-30
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Granted: 1971-12-28
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Expires: 1989-04-30
Abstract
Abstract A method for fabricating cathodes with a lanthanum boride coating is disclosed in which the coating is applied to any base metal by spraying with a plasma flame spray. One plasma source is a spray gun utilizing an electric arc discharge through which a plasma gas is passed so that a plasma of ionized gas issues from the spray gun into which is injected a carrier gas having lanthanum boride powder suspended therein. The high-temperature plasma flame appearing at the nozzle of the spray gun melts the lanthanum boride (LaB6) almost instantly and the droplets formed thereby are carried to the surface of a prepared base material.
Inventors
- 👤 Louis J Favreau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:34
CPC Classifications
H; H05; H05H; H05H1/00; H05H1/24; H05H1/26; H05H1/32; H05H1/42; B; B05; B05B; B05B7/00; B05B7/16; B05B7/22; B05B7/222; B05B7/226; C; C23; C23C; C23C4/00; C23C4/04; C23C4/10; H01; H01J; H01J9/00; H01J9/02; H01J9/04; H01J9/042; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
40 words
A method for making a lanthanum-boride-coated cathode having improved thermionic emission characteristics and a tenacious bond between the lanthanum boride and a cathode base metal, said method comprising spraying molten lanthanum boride on the surface of said cathode base metal.
Claim 2
Independent Claim
40 words
A method for making a lanthanum-boride-coated cathode having improved thermionic emission characteristics and a tenacious bond between the lanthanum boride and a cathode base metal, said method comprising spraying molten lanthanum boride on the surface of said cathode base metal.
Claim 3
Dependent Claim
75 words
The method for making a lanthanum-boride-coated cathode as recited in claim 1 wherein the step of spraying comprises: formulating a plasma gas with hydrogen and a gas selected from the group consisting of argon, nitrogen, and helium, introducing the plasma gas into an electric arc to create a plasma of ionized gas, and injecting lanthanum boride powder into the plasma of ionized gas whereby the heat created by the electric arc melts the lanthanum boride.
Claim 4
Dependent Claim
36 words
The method for making a lanthanum-boride-coated cathode as recited in claim 2 further comprising the step of: cleaning the surface of the metal to be sprayed by washing with a solvent and blasting with an abrasive.
Claim 5
Dependent Claim
47 words
The method for making a lanthanum-boride-coated cathode as recited in claim 3 wherein the step of injecting lanthanum boride powder into the plasma of ionized gas further comprises suspending the lanthanum boride powder in a carrier gas selected from the group consisting of argon, nitrogen, and helium.
Claim 6
Dependent Claim
49 words
The method for making a lanthanum-boride-coated cathode as recited in claim 2 wherein the step of formulating a plasma gas comprises: mixing 5 to 15 percent of hydrogen with 95 to 85 percent by volume respectively, of a gas selected from the group consisting of argon, nitrogen, and helium.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein the cathode base metal is selected from the group consisting of tungsten, rhenium, tantalum, nickel, and molybdenum.
References Cited (Backward Citations)
US2659685A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |