AT136841B - Process for the production of a hot cathode of high electron emission with an intermediate layer. - Google Patents
Process for the production of a hot cathode of high electron emission with an intermediate layer.Info
- Publication number
- AT136841B AT136841B AT136841DA AT136841B AT 136841 B AT136841 B AT 136841B AT 136841D A AT136841D A AT 136841DA AT 136841 B AT136841 B AT 136841B
- Authority
- AT
- Austria
- Prior art keywords
- intermediate layer
- oxide
- electron emission
- production
- hot cathode
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims description 5
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 5
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 239000007858 starting material Substances 0.000 claims description 4
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 claims description 2
- 230000003647 oxidation Effects 0.000 claims description 2
- 238000007254 oxidation reaction Methods 0.000 claims description 2
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 claims 2
- 230000007717 exclusion Effects 0.000 claims 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- -1 B. WOg Chemical compound 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 230000008022 sublimation Effects 0.000 description 2
- 238000000859 sublimation Methods 0.000 description 2
- 241000593357 Austroderia fulvida Species 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052756 noble gas Inorganic materials 0.000 description 1
- 150000002835 noble gases Chemical class 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
Landscapes
- Solid Thermionic Cathode (AREA)
Description
<Desc/Clms Page number 1>
Verfahren zur Herstellung einer Glühkathode hoher Elektronenemission mit Zwisehensehieht.
Gegenstand der Erfindung ist ein Verfahren, die Wirksamkeit der bisherigen Oxydkathoden dadurch zu erhöhen, dass man durch eine nachträgliche Verdampfung eines Erdalkalimetalles, beispielsweise Barium, auf die Oxydkathode einen Film reinen Erdalkalimetalles aufbringt. Hiedurch vergrössert sich die für die Elektronenemission aktive Oberfläche der Glühkathode, wodurch eine erhöhte Elektronenemission bedingt wird.
Eine derartige Erdalkalikathode gemäss vorliegender Erfindung kann beispielsweise in der Weise hergestellt werden, dass zunächst in bekannter Weise ein Erdalkalimetall durch Verdampfung oder Sublimierung unter Ausschluss jeder äusseren Oxydationsmöglichkeit auf einen oxydierten Träger aufgebracht wird. So eignet sich gut Wolframdraht, der mit einer Schicht eines Wolframoxydes, z. B. WOg, bedeckt ist, zur Herstellung der Zwischenschicht aus aufgedampften Ausgangsmaterialien, z. B. Barium.
Strontium, Calcium oder Mischungen davon. Diese reagieren mit dem Sauerstoff des auf dem Träger befindlichen Oxydes und bilden Erdalkalioxyde, vorzugsweise dann, wenn der Träger erhitzt wird.
Eine so vorbehandelte Kathode stellt eine normale Oxydkathode dar. In einem zweiten Stadium des Prozesses wird auf diese Oxydkathode durch Verdampfung oder Sublimation eine dünne Schicht eines Erdalkalimetalles verdampft oder sublimiert. Die zu verdampfenden Ausgangsstoffe können von einer hiezu besonders vorgesehenen oder von einer der vorhandenen Elektroden, z. B. von der Anode aus, zum Verdampfen gebracht werden. Zur Beschleunigung des Pumpverfahrens und zur sicheren Beseitigung von Sauerstoffresten ist die Anwendung von Getterstoffen vorteilhaft, wobei die Ausgangsstoffe der Schichten zweckmässig durch Steigern der Temperatur in derjenigen Reihenfolge zum Verdampfen gebracht werden, in der sie zum Aufbau der Kathode gebraucht werden.
Die Evakuierung muss vor dem Aufbringen der letzten Metallschicht soweit getrieben werden, dass auch die Elektroden bei weiterer Erhitzung keine okkludierten Gase mehr abgeben. Eine in dieser Weise hergestellte Kathode ist nicht als Oxydkathode anzusehen, wofür der Umstand zum Beweise dienen kann, dass schon bei Zufuhr einer geringen Menge Sauerstoff, der die Metallschicht oxydiert, die Elektronenausbeute auf ein Drittel bis ein Viertel des vorherigen Wertes heruntergeht.
Die neue Kathode eignet sich zur Verwendung im Hochvakuum als auch in einer Atmosphäre von Edelgasen, z. B. Argon, sowie besonders für indirekte Heizung und in solchen Röhren, bei denen ein möglichst kleiner Spannungsabfall an der Kathode erwünscht ist.
**WARNUNG** Ende DESC Feld kannt Anfang CLMS uberlappen**.
<Desc / Clms Page number 1>
Method of manufacturing a high-emission hot cathode with toe-toe.
The invention relates to a method of increasing the effectiveness of the previous oxide cathodes by applying a film of pure alkaline earth metal to the oxide cathode by subsequent evaporation of an alkaline earth metal, for example barium. This increases the surface of the hot cathode that is active for electron emission, which results in increased electron emission.
Such an alkaline earth cathode according to the present invention can for example be produced in such a way that an alkaline earth metal is first applied to an oxidized carrier in a known manner by evaporation or sublimation, excluding any external possibility of oxidation. So tungsten wire is well suited, which is coated with a layer of tungsten oxide, e.g. B. WOg, is covered, for the production of the intermediate layer from vapor-deposited starting materials, for. B. Barium.
Strontium, calcium or mixtures thereof. These react with the oxygen of the oxide on the carrier and form alkaline earth oxides, preferably when the carrier is heated.
A cathode pretreated in this way represents a normal oxide cathode. In a second stage of the process, a thin layer of an alkaline earth metal is evaporated or sublimed onto this oxide cathode by evaporation or sublimation. The starting materials to be evaporated can be supplied by a specially provided or by one of the existing electrodes, e.g. B. from the anode, are made to evaporate. To accelerate the pumping process and to safely remove oxygen residues, the use of getter materials is advantageous, the starting materials of the layers being expediently made to evaporate by increasing the temperature in the order in which they are needed to build up the cathode.
Before the last metal layer is applied, the evacuation must be carried out to such an extent that the electrodes no longer emit any occluded gases if they are heated further. A cathode manufactured in this way is not to be regarded as an oxide cathode, for which the fact can serve as evidence that even with a small amount of oxygen, which oxidizes the metal layer, the electron yield drops to a third to a quarter of the previous value.
The new cathode is suitable for use in a high vacuum as well as in an atmosphere of noble gases, e.g. B. argon, and especially for indirect heating and in such tubes where the smallest possible voltage drop at the cathode is desired.
** WARNING ** End of DESC field may overlap beginning of CLMS **.
Claims (1)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE136841T | 1927-04-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AT136841B true AT136841B (en) | 1934-03-10 |
Family
ID=29278028
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AT136841D AT136841B (en) | 1927-04-02 | 1928-03-31 | Process for the production of a hot cathode of high electron emission with an intermediate layer. |
Country Status (1)
| Country | Link |
|---|---|
| AT (1) | AT136841B (en) |
-
1928
- 1928-03-31 AT AT136841D patent/AT136841B/en active
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