US2586768A - Vacuum tube electrode element - Google Patents
Vacuum tube electrode element Download PDFInfo
- Publication number
- US2586768A US2586768A US78233A US7823349A US2586768A US 2586768 A US2586768 A US 2586768A US 78233 A US78233 A US 78233A US 7823349 A US7823349 A US 7823349A US 2586768 A US2586768 A US 2586768A
- Authority
- US
- United States
- Prior art keywords
- nickel
- vacuum tube
- percent
- electrode element
- lanthanum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 150000002739 metals Chemical class 0.000 claims description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 58
- 229910052759 nickel Inorganic materials 0.000 description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- 229910001122 Mischmetal Inorganic materials 0.000 description 9
- 229910052746 lanthanum Inorganic materials 0.000 description 9
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 9
- 229910052684 Cerium Inorganic materials 0.000 description 8
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 8
- 229910052761 rare earth metal Inorganic materials 0.000 description 7
- 150000002910 rare earth metals Chemical class 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 229910000722 Didymium Inorganic materials 0.000 description 3
- 241000224487 Didymium Species 0.000 description 3
- 230000003213 activating effect Effects 0.000 description 3
- 229910000480 nickel oxide Inorganic materials 0.000 description 3
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical class [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Chemical compound [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Inorganic materials [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- -1 iron and cobalt Chemical class 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/14—Solid thermionic cathodes characterised by the material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
- H01J19/28—Non-electron-emitting electrodes; Screens
- H01J19/30—Non-electron-emitting electrodes; Screens characterised by the material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2893/00—Discharge tubes and lamps
- H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
- H01J2893/0012—Constructional arrangements
- H01J2893/0019—Chemical composition and manufacture
- H01J2893/002—Chemical composition and manufacture chemical
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2913—Rod, strand, filament or fiber
- Y10T428/2933—Coated or with bond, impregnation or core
- Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
- Y10T428/2958—Metal or metal compound in coating
Definitions
- sive coating generally an alkaline earth oxide on its surface.
- the electrode elements such as a oath-- ode, are usually formed of a sleeve or wire of nickel coated with active oxides, such as barium or strontium oxide.
- active oxides such as barium or strontium oxide.
- the nickel used in the production of such cathodes will, of course, vary in composition.
- the preparation of the nickel in the form in which it is to be used for the manufacture of cathode elements requires the melting of ingots and in this melting operation there is a tendency to form oxides.
- the base nickel metal is substantially free of silicon, magnesium, titanium, aluminum and similar deoxidizers. These are the deoxidizers which are normally used in melting nickel to produce a malleable material which can be rolled to thin sheets of the order of .002 to .005" thick.
- Inactive metals, such as iron and cobalt, are not considered harmful if not present in too large quantities.
- slabs of electrolytically deposited nickel are melted in the usual manner, the normal procedure being followed up to the point where the metal is completely molten.
- Misch metal In actual practice, I have employed one pound of Misch metal to a 1300 pound melt. This figure may, of course, vary. If the melting of the slabs is carried out in a manner that would normally result in the production of a minimum amount of nickel oxides, the quantity of Misch metal added may be less. Greater quantities of Misch metal up to as much as three pounds may be added.
- the rare earth metals added to the melt reduce the nickel xides to nickel and the resulting rare earth oxides disappear from the molten bath.
- the nickel so produced contains no more impurities than are present in the nickel slabs with the exception of the small amount of iron referred to. It is malleable, easily worked and annealed and therefore does not require the annealing treatments which are necessary with a nickel of high carbon content.
- the desired quantities of rare earth metals such as cerium, lanthanum and didymium may be added directly.
- the nickel produced would not contain the slight contamination of iron.
- a vacuum tube having electrode elements at least one of which is composed of nickel and traces of rare earth metals.
- a vacuum tube having electrode elements at least one of which is composed of nickel and traces of cerium and lanthanum.
- a vacuum tube having electrode elements at least one of which is composed of nickel, a trace to 0.2 percent cerium and a trace to 0.2 percent lanthanum.
- a cathode element for a vacuum tube consisting of nickel containing traces of rare earth metals, and an activating agent comprising an oxide coating thereon.
- a cathode element for a vacuum tube consisting of nickel containing traces of cerium and lanthanum, and an activating agent comprising an oxide coating thereon.
- a cathode element for a vacuum tube consisting of nickel containing a trace to 0.2 percent cerium and a trace to 0.2 percent lanthanum, and an activating agent comprising an oxide coating thereon.
Description
Patented Feb. 26, 1 952 VACUUM TUBE ELECTRODEaELEMF- NT Francis E. Bash, Morristown, N, J., assignpr t Driver-Harris Company, Harrison, N. .1., a; cornotation of New Jersey No prawing. Application February 24, 1949, w Serial No. 78,233
sive coating, generally an alkaline earth oxide on its surface.
With the highamplification factors in vacuum tubes employed today electron emission from the grids and anodes of the tubes must be reduced to a minimum as this emission causes considerable background noises and a reduction of efiiciency. The electrode elements, such as a oath-- ode, are usually formed of a sleeve or wire of nickel coated with active oxides, such as barium or strontium oxide. The nickel used in the production of such cathodes will, of course, vary in composition. The preparation of the nickel in the form in which it is to be used for the manufacture of cathode elements requires the melting of ingots and in this melting operation there is a tendency to form oxides. Heretofore it has been the usual practice to add various deoxidizing agents, such as magnesium, silicon, calcium or the like to the melt to keep the formation of nickel oxides at a minimum. However, to effectively deoxidize the nickel, it has been found necessary to use an excess of such deoxidizers with the result that small amounts of these deoxidizers remain in the melt. It has been established that emissions of electrons from the oxide coated cathode are increased by the presence of such deoxidizing elements in the nickel from which the oathode is made.
Sub-Committee VIII on Metallic Materials for Radio Tubes and Incandescent Lamps, of Committee 3-4 on Electrical Heating, Resistance, and Related Alloys, of The American Society for Testing Materials, has classified cathode materials into passive, normal and active. In the passive type the base nickel metal is substantially free of silicon, magnesium, titanium, aluminum and similar deoxidizers. These are the deoxidizers which are normally used in melting nickel to produce a malleable material which can be rolled to thin sheets of the order of .002 to .005" thick. Inactive metals, such as iron and cobalt, are not considered harmful if not present in too large quantities.
The necessity of deoxidizing any nickel oxides formed during the melt and at the same time of producing a final nickel product from which the usual deoxidizing elements are absent, has resulted in the practice of manufacturing the passive type electrodes from electrolytically de- 6 c s. (01. era-s46) positednickel. The slabs of electrolytic nickel are melted with carbon additions, thecarbo'n being added to reduc'the oxides'in the molten bath to produce the nickel m'ardrnwmch canlb'e hotan d cold rolled to produce thin sheets. I-Ie're again, the deoxidize'r m'ustbe used in' an excess so that at the end of the melt the nickel contains from .20 to .50 percent carbon; It-is then necessary to later remove the carbonfrom the nickel by heating it in the presence 'of' wet hydrogen. This operation is along and expensive onland again has a tendency to oxidizethelnickel sheet after the carbon has been removed.
I have found that slabs of electrolytically deposited nickel can be melted to produce a malleable metal which can be hot and cold worked without adding either the usual deoxidizers, the presence of which in the final nickel product is objectionable, or without adding carbon in excess. I accomplish this by the addition of rare earth metals, such as are found in the alloy known as Misch metal. While the composition of Misch metal varies, generally speaking, it consists essentially of 40 percent cerium, 30 percent lanthanum, and 30 percent didymium, balance ytterbium and iron. The lanthanum and didymium proportions of the Misch metal may contain small quantities of the other rare earth metals.
In carrying out the invention, slabs of electrolytically deposited nickel are melted in the usual manner, the normal procedure being followed up to the point where the metal is completely molten. At that point I add a small quantity of Misch metal to the bath. In actual practice, I have employed one pound of Misch metal to a 1300 pound melt. This figure may, of course, vary. If the melting of the slabs is carried out in a manner that would normally result in the production of a minimum amount of nickel oxides, the quantity of Misch metal added may be less. Greater quantities of Misch metal up to as much as three pounds may be added. The rare earth metals added to the melt reduce the nickel xides to nickel and the resulting rare earth oxides disappear from the molten bath. Spectrographic analyses of the cast and processed metal show traces of cerium and lanthanum. The amounts of cerium and lanthanum present do not exceed .2 percent. Likewise, if iron is present in the Misch metal, it is retained in the nickel forming about .12 to a maximum of .20 percent of the final product. The presence of such a effect and the nickel so produced is entirely satisfactory for the manufacture of passive cathode elements.
The nickel so produced contains no more impurities than are present in the nickel slabs with the exception of the small amount of iron referred to. It is malleable, easily worked and annealed and therefore does not require the annealing treatments which are necessary with a nickel of high carbon content.
Instead of adding the rare earth metals in the form of Misch metal, the desired quantities of rare earth metals, such as cerium, lanthanum and didymium may be added directly. In such case the nickel produced would not contain the slight contamination of iron.
I claim:
1. A vacuum tube having electrode elements at least one of which is composed of nickel and traces of rare earth metals.
2. A vacuum tube having electrode elements at least one of which is composed of nickel and traces of cerium and lanthanum.
3. A vacuum tube having electrode elements at least one of which is composed of nickel, a trace to 0.2 percent cerium and a trace to 0.2 percent lanthanum.
4. A cathode element for a vacuum tube consisting of nickel containing traces of rare earth metals, and an activating agent comprising an oxide coating thereon.
5. A cathode element for a vacuum tube consisting of nickel containing traces of cerium and lanthanum, and an activating agent comprising an oxide coating thereon.
6. A cathode element for a vacuum tube consisting of nickel containing a trace to 0.2 percent cerium and a trace to 0.2 percent lanthanum, and an activating agent comprising an oxide coating thereon.
FRANCIS E. BASH.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS
Claims (1)
1. A VACUUM TUBE HAVING ELECTRODE ELEMENTS AT LEAST ONE OF WHICH IS COMPOSED OF NICKEL AND TRACES OF RATE EARTH METALS.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US78233A US2586768A (en) | 1949-02-24 | 1949-02-24 | Vacuum tube electrode element |
| GB3244/50A GB713063A (en) | 1949-02-24 | 1950-02-08 | Improvements in electrode elements |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US78233A US2586768A (en) | 1949-02-24 | 1949-02-24 | Vacuum tube electrode element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2586768A true US2586768A (en) | 1952-02-26 |
Family
ID=22142771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US78233A Expired - Lifetime US2586768A (en) | 1949-02-24 | 1949-02-24 | Vacuum tube electrode element |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2586768A (en) |
| GB (1) | GB713063A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2911376A (en) * | 1951-11-01 | 1959-11-03 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Activating material for electrodes in electric discharge devices |
| US2924737A (en) * | 1957-05-20 | 1960-02-09 | Philips Corp | Glow discharge tube |
| US2983602A (en) * | 1957-09-24 | 1961-05-09 | Armour Res Found | Cobalt alloys |
| US3312856A (en) * | 1963-03-26 | 1967-04-04 | Gen Electric | Rhenium supported metallic boride cathode emitters |
| FR2401230A1 (en) * | 1977-08-27 | 1979-03-23 | Ngk Spark Plug Co | NICKEL-BASED ALLOY SUITABLE PARTICULARLY FOR THE HEATING ELEMENT OF AN INCANDESCENT CANDLE |
| US4612164A (en) * | 1984-11-01 | 1986-09-16 | Inco Alloys International, Inc. | Nickel copper alloys with enhanced malleability and improved sulfide distribution |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1689338A (en) * | 1921-11-19 | 1928-10-30 | Western Electric Co | Electron-discharge device |
| US1753298A (en) * | 1927-01-03 | 1930-04-08 | New Process Metals Corp | Purifying rare gases |
| US1916410A (en) * | 1928-08-22 | 1933-07-04 | Westinghouse Electric & Mfg Co | Alloy |
| US2075718A (en) * | 1935-03-07 | 1937-03-30 | Firm Heraeus Vacuumachmetze Ag | Heat-resisting implement |
| US2204391A (en) * | 1939-04-29 | 1940-06-11 | Rca Corp | Cathode for electron discharge devices |
| US2246162A (en) * | 1938-08-17 | 1941-06-17 | Gen Electric | Thermionic cathode treatment |
| US2304353A (en) * | 1935-05-09 | 1942-12-08 | Int Nickel Co | Heat resistant alloy |
| US2456370A (en) * | 1945-02-19 | 1948-12-14 | Int Nickel Co | Process for producing electrodeposited nickel strip containing boron |
-
1949
- 1949-02-24 US US78233A patent/US2586768A/en not_active Expired - Lifetime
-
1950
- 1950-02-08 GB GB3244/50A patent/GB713063A/en not_active Expired
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1689338A (en) * | 1921-11-19 | 1928-10-30 | Western Electric Co | Electron-discharge device |
| US1753298A (en) * | 1927-01-03 | 1930-04-08 | New Process Metals Corp | Purifying rare gases |
| US1916410A (en) * | 1928-08-22 | 1933-07-04 | Westinghouse Electric & Mfg Co | Alloy |
| US2075718A (en) * | 1935-03-07 | 1937-03-30 | Firm Heraeus Vacuumachmetze Ag | Heat-resisting implement |
| US2304353A (en) * | 1935-05-09 | 1942-12-08 | Int Nickel Co | Heat resistant alloy |
| US2246162A (en) * | 1938-08-17 | 1941-06-17 | Gen Electric | Thermionic cathode treatment |
| US2204391A (en) * | 1939-04-29 | 1940-06-11 | Rca Corp | Cathode for electron discharge devices |
| US2456370A (en) * | 1945-02-19 | 1948-12-14 | Int Nickel Co | Process for producing electrodeposited nickel strip containing boron |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2911376A (en) * | 1951-11-01 | 1959-11-03 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Activating material for electrodes in electric discharge devices |
| US2924737A (en) * | 1957-05-20 | 1960-02-09 | Philips Corp | Glow discharge tube |
| US2983602A (en) * | 1957-09-24 | 1961-05-09 | Armour Res Found | Cobalt alloys |
| US3312856A (en) * | 1963-03-26 | 1967-04-04 | Gen Electric | Rhenium supported metallic boride cathode emitters |
| FR2401230A1 (en) * | 1977-08-27 | 1979-03-23 | Ngk Spark Plug Co | NICKEL-BASED ALLOY SUITABLE PARTICULARLY FOR THE HEATING ELEMENT OF AN INCANDESCENT CANDLE |
| US4612164A (en) * | 1984-11-01 | 1986-09-16 | Inco Alloys International, Inc. | Nickel copper alloys with enhanced malleability and improved sulfide distribution |
Also Published As
| Publication number | Publication date |
|---|---|
| GB713063A (en) | 1954-08-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2586768A (en) | Vacuum tube electrode element | |
| US2103267A (en) | Alloy for vacuum tube elements | |
| US2566115A (en) | Alloy for cathode element | |
| US2672414A (en) | Chromium-titanium steel adapted for sealing to glass | |
| US2192491A (en) | Cathode for electron discharge devices | |
| JPS5952503B2 (en) | Substrate metal plate for directly heated oxide cathode | |
| US2306290A (en) | Cathode alloy | |
| GB816135A (en) | Workable alloys of molybdenum and tungsten containing rhenium | |
| US1883898A (en) | Thermionic cathode | |
| US2179110A (en) | Cathode for electron discharge devices | |
| US2380200A (en) | Magnesium base alloy | |
| US1961122A (en) | Thermionic cathode | |
| US2323173A (en) | Electrode wire | |
| US2185410A (en) | Metal compositions | |
| US1732326A (en) | Thorium alloy and method of preparing the same | |
| US2172968A (en) | Electric discharge tube | |
| US2241565A (en) | Grid electrode | |
| US2140367A (en) | Thermionic cathode | |
| US2001888A (en) | Spark plug electrode | |
| US1747063A (en) | Electrode composition for electron-discharge devices | |
| US2396977A (en) | Electrode alloys | |
| US2240064A (en) | Alloy for metal to glass seals | |
| US2209708A (en) | Cathode manufacture | |
| DE880181C (en) | Electrode element for vacuum tubes | |
| US1916410A (en) | Alloy |