EP0673051B1 - Dispenser cathode - Google Patents
Dispenser cathode Download PDFInfo
- Publication number
- EP0673051B1 EP0673051B1 EP95103216A EP95103216A EP0673051B1 EP 0673051 B1 EP0673051 B1 EP 0673051B1 EP 95103216 A EP95103216 A EP 95103216A EP 95103216 A EP95103216 A EP 95103216A EP 0673051 B1 EP0673051 B1 EP 0673051B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- metal
- group
- chromium oxide
- dispenser cathode
- cathodes
- 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
Images
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
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
- H01J1/28—Dispenser-type cathodes, e.g. L-cathode
Definitions
- the present invention relates to a supply cathode according to the preamble of claim 1.
- Storage cathodes are also referred to as matrix cathodes or dispenser cathodes. They generally consist of a storage body which is pressed or sintered from a metal powder and which is impregnated with the actual emission material. Metals such as tungsten and molybdenum are particularly suitable as metal powder for the storage body. It is also known to use mixtures of such metal powders. From DE-OS 20 48 224 it is known to press the storage body into a cavity in a cathode sleeve. From DE-OS 41 14 856 it is For example, it is known to build up the storage body in layers. The porous matrix body can be impregnated with an emission material consisting, for example, of BaO-CaO-Al 2 O 3 , by impregnation, melting or the like.
- MM cathodes mixed metal cathodes
- the stock bodies of mixed metal cathodes generally consist of metals from a first group, such as tungsten, chromium or molybdenum, and metals from a second group, such as iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh ), Paladium (Pd), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt).
- a first group such as tungsten, chromium or molybdenum
- metals from a second group such as iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh ), Paladium (Pd), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt).
- US Pat. No. 2,995,674 describes a supply cathode in which a porous tungsten sintered body is impregnated with an emission material which contains barium oxide and chromium oxide.
- the emissivity of the cathodes can be improved by adding scandium compounds in the cathode body or in the emission material.
- scandium compounds in the cathode body or in the emission material.
- scandium compounds in the cathode body or in the emission material.
- the present invention is therefore based on the object of improving a storage cathode of the type mentioned at the outset, in particular with regard to electron emission (high current density) with a long service life.
- FIG. 1 schematically shows the structure of a supply cathode with an emission surface 6.
- the cathode body 1 which can also consist of two or three layers, is, for example, pressed into the cathode holder 2 (for example from molybdenum) by pressing a powder mixture (for example W + Os + Cr 2 O 3 ) ) manufactured. After sintering, the emission material (eg BaO + CaO + Al 2 O 3 ) is filled, for example by soaking.
- the heater 3 is embedded, for example, with Al 2 O 3 4 in a pot 5 made of molybdenum, which is attached to the cathode holder 2.
- FIG. 2 shows the electron work function (e ⁇ / eV), the value of which was determined from current-voltage characteristics (measured at 1000 ° C.) according to known methods, as a function of the cathode temperature (T in ° C.).
- the work function for cathodes with Cr 2 O 3 addition is also low temperatures about 0.1 eV lower than for cathodes without additives, at high temperatures about 0.05 eV.
- FIG. 3 shows the change in work function (e ⁇ / eV) (for 1000 ° C) during operation with (to accelerate aging) increased temperature (1100 ° C) over the operating time in hours (h).
- the work function for cathodes with Cr 2 O 3 addition drops slightly at the beginning of operation and remains practically constant during the observation period (almost 10,000 hours).
- the work function for cathodes without additives increases, so that after 1000 hours their value is about 0.1 eV higher than for cathodes with Cr 2 O 3 .
- FIG. 4 shows, as an example of the size of the current that can be achieved, the change in saturation current over time (current density j in A / cm 2 ) at a field strength of 35 kV / cm over the operating time t (h).
- the saturation current behaves according to the work function (FIG. 3); it changes less for cathodes with Cr 2 O 3 addition than for those without addition.
- the saturation current for cathodes with Cr 2 O 3 addition is still about twice as large as the current for cathodes without addition. (Both types show practically no waste at low temperatures).
- the chromium oxide additive is added to the sintered body of the cathode body.
- This is advantageously done in such a way that powdered chromium oxide (Cr 2 O 3 ) is added to the powder or powders of the metals of the first group and the second group, this mixture is then pressed and is then sintered into a porous sintered body.
- the chromium oxide content of the powder mixture is 1-20% by weight, preferably 7-14% by weight, in particular approximately 10% by weight.
- the other powder fractions preferably consist of tungsten and osmium, the tungsten fraction expediently not to be smaller than the osmium fraction.
- the metal of the second group for example osmium, can be dispensed with entirely.
- the chromium oxide additive according to the invention is particularly advantageous for use with a storage cathode, the storage body consists of several superimposed and sintered sintered layers, as described for example in DE-OS 41 14 856 A1.
- the layer sintering described there consists of at least two layers which consist of essentially the same materials. However, the percentage by weight of the materials differs in at least two adjacent layers in such a way that in one layer the proportion of the metal of the first group is greater than the proportion of the metal in the second group and in the other layer the proportion of the metal in the second group is greater than the proportion of metal in the first group.
- chromium oxide should also be present at least in the layer having the emission surface 6, the chromium oxide being contained in the sintered body.
- Such a supply cathode is preferably produced with a multilayer cathode body using a method known from DE-OS 4 114 856, in which the sintered body is produced with an additional layer and this additional layer is removed again after sintering.
- FIG. 5 shows in the right half a cross section through a sintered body with a first layer 11, a second layer 12 and a third layer 13 in a cathode holder 2.
- the first layer is essentially composed of a metal powder mixture of more than 50% by weight, preferably more produced as 70% by weight of tungsten and the rest of osmium.
- the third layer 13 is preferably composed in exactly the same way as the first layer.
- the second layer 12 is produced from a mixture of tungsten metal powder, osmium metal powder and approximately 10% by weight of chromium oxide powder, the content of osmium being higher than in layers 11 and 13 and preferably more than 50% by weight. is.
- the various powder mixtures are successively filled into the cathode holder, pressed under high pressure and sintered together.
- the third layer 13 and part of the second layer 12 up to the broken line are removed after sintering, e.g. by grinding, so that a two-layer cathode body sketched in the left half of FIG. 5 is formed with the emission surface 6 forming the exposed surface of the second layer.
- the metal matrix is preferably filled (impregnated) with the emission material before the third and part of the second layer are removed.
Landscapes
- Solid Thermionic Cathode (AREA)
- Powder Metallurgy (AREA)
Description
Die vorliegende Erfindung betrifft eine Vorratskathode nach dem Oberbegriff des Patentanspruches 1.The present invention relates to a supply cathode according to the preamble of claim 1.
Vorratskathoden werden auch als Matrix-Kathoden oder Dispenser-Kathoden bezeichnet. Sie bestehen im allgemeinen aus einem Vorratskörper, der aus einem Metallpulver gepreßt oder gesintert ist und der mit dem eigentlichen Emissionsmaterial imprägniert ist. Als Metallpulver für den Vorratskörper kommen insbesondere Metalle wie Wolfram und Molybdän in Frage. Es ist auch bekannt, Mischungen solcher Metallpulver zu verwenden. Aus der DE-OS 20 48 224 ist es bekannt, den Vorratskörper in eine Höhlung einer Kathodenhülse einzupressen. Aus der DE-OS 41 14 856 ist es z.B. bekannt, den Vorratskörper schichtförmig aufzubauen. Die Imprägnierung des porösen Matrix-Körpers mit einem Emissionsmaterial, das z.B. aus BaO-CaO-Al2O3 besteht, kann durch Tränken, Einschmelzen oder dergleichen erfolgen.Storage cathodes are also referred to as matrix cathodes or dispenser cathodes. They generally consist of a storage body which is pressed or sintered from a metal powder and which is impregnated with the actual emission material. Metals such as tungsten and molybdenum are particularly suitable as metal powder for the storage body. It is also known to use mixtures of such metal powders. From DE-OS 20 48 224 it is known to press the storage body into a cavity in a cathode sleeve. From DE-OS 41 14 856 it is For example, it is known to build up the storage body in layers. The porous matrix body can be impregnated with an emission material consisting, for example, of BaO-CaO-Al 2 O 3 , by impregnation, melting or the like.
Allgemein hat sich gezeigt, daß sogenannte Mischmetall-Kathoden (MM-Kathoden), d.h. also Kathoden, deren Vorratskörper aus einem Metallpulvergemisch gepreßt und gesintert sind, verbesserte Emissionseigenschaften und eine bessere Stromstabilität aufweisen. Die Vorratskörper von Mischmetall-Kathoden bestehen im allgemeinen aus Metallen einer ersten Gruppe wie Wolfram, Chrom oder Molybdän und Metallen einer zweiten Gruppe, wie Eisen (Fe), Kobalt (Co), Nickel (Ni), Ruthenium (Ru), Rhodium (Rh), Paladium (Pd), Rhenium (Re), Osmium (Os), Iridium (Ir), Platin (Pt).In general, it has been shown that so-called mixed metal cathodes (MM cathodes), i.e. that is, cathodes, whose storage bodies are pressed and sintered from a metal powder mixture, have improved emission properties and better current stability. The stock bodies of mixed metal cathodes generally consist of metals from a first group, such as tungsten, chromium or molybdenum, and metals from a second group, such as iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh ), Paladium (Pd), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt).
Aus der DE-PS 30 17 429 ist weiterhin bekannt, Wolfram oder Wolframoxid dem Emissionsmaterial zuzusetzen.From DE-PS 30 17 429 it is also known to add tungsten or tungsten oxide to the emission material.
In der US-A-2 995 674 ist eine Vorratskathode beschrieben, bei welcher ein poröser Wolfram-Sinterkörper mit einem Emissions material getränkt ist, das Bariumoxid und Chromoxid enthält.US Pat. No. 2,995,674 describes a supply cathode in which a porous tungsten sintered body is impregnated with an emission material which contains barium oxide and chromium oxide.
Weiter ist bekannt, daß durch Zusatz von Scandium-Verbindungen im Kathodenkörper oder im Emissionsmaterial die Emissionsfähigkeit der Kathoden verbessert werden kann. Allerdings sind die Langzeit-Eigenschaften dieser sogenannten "Scandat-Kathoden" bisher noch nicht befriedigend.It is also known that the emissivity of the cathodes can be improved by adding scandium compounds in the cathode body or in the emission material. However, the long-term properties of these so-called "scandate cathodes" have so far not been satisfactory.
Der vorliegenden Erfindung liegt daher die Aufgabe zugrunde, eine Vorratskathode der eingangs genannten Art insbesondere hinsichtlich der Elektronenemission ( hoher Stromdichte) bei langer Lebensdauer zu verbessern.The present invention is therefore based on the object of improving a storage cathode of the type mentioned at the outset, in particular with regard to electron emission (high current density) with a long service life.
Diese Aufgabe wird durch die im Kennzeichen des Patentanspruches 1 angegebenen Merkmale gelöst.This object is achieved by the features specified in the characterizing part of patent claim 1.
Bei Versuchen mit verschiedenen Zusätzen hat sich gezeigt, daß mit einer Beimischung von Cr2O3-Pulver insbesondere zum Mischmetall-Pulver Kathoden mit merklich verbesserten Emissionseigenschaften erhalten werden können. Insbesondere bei Vorratskathoden mit einem Vorratskörper in Schichtaufbau wie z.B. in der DE 41 14 856 A1 beschrieben, konnten bei gleicher Kathodentemperatur eine gegenüber einer Kathode ohne Chromoxid- Zusatz etwa doppelt so große Stromdichten erreicht werden, die sich auch nach längerer Betriebszeit kaum änderten. Entsprechend ist die Austrittsarbeit ( für 1000°C) bei Kathoden mit z.B. 10% Cr2O3-Zusatz zu einem W/Os-Pulver um etwa 0,1 eV niedriger als bei den Kathoden ohne Zusatz.Experiments with various additives have shown that with an admixture of Cr 2 O 3 powder, in particular to the mixed metal powder, cathodes with noticeably improved emission properties can be obtained. Particularly in the case of storage cathodes with a storage body in a layer structure, as described, for example, in DE 41 14 856 A1, at the same cathode temperature it was possible to achieve a current density which was about twice as large as that of a cathode without addition of chromium oxide and which hardly changed even after a long operating time. Correspondingly, the work function (for 1000 ° C.) for cathodes with, for example, 10% Cr 2 O 3 addition to a W / Os powder is about 0.1 eV lower than for the cathodes without addition.
Anhand der Figuren wird die Erfindung nachfolgend näher erklärt.
- FIG. 1
- zeigt schematisch einen Querschnitt durch eine Vorratskathode dessen Kathodenkörper auch aus zwei oder drei übereinanderliegenden Schichten bestehen kann.
- FIG. 2
- zeigt eine Kurve der Austrittsarbeit in Abhängigkeit von der Kathodentemperatur für eine Mischmetallkathode (W/Os) mit und ohne Chromoxid- Zusatz (vor Lebensdauer-Betrieb).
- FIG. 3
- zeigt eine Kurve der Austrittsarbeit bei 1000°C in Abhängigkeit von der Betriebszeit bei erhöhter Kathodentemperatur (1100°C) für Mischmetallkathoden (W/Os) mit und ohne Chromoxid- Zusatz.
- FIG. 4
- zeigt eine Kurve des Sättigungsstroms für 35 kV/cm in Abhängigkeit von der Betriebszeit für Mischmetallkathoden (W/Os) mit und ohne Chromoxid- Zusatz.
- FIG. 5
- zeigt schematisch einen Querschnitt durch einen Kathodenkörper mit zwei Schichten und dessen Herstellung aus einem dreischichtigen Sinterkörper.
- FIG. 1
- shows schematically a cross section through a supply cathode whose cathode body can also consist of two or three layers lying one above the other.
- FIG. 2nd
- shows a curve of the work function as a function of the cathode temperature for a mixed metal cathode (W / Os) with and without addition of chromium oxide (before service life).
- FIG. 3rd
- shows a curve of the work function at 1000 ° C depending on the operating time at elevated cathode temperature (1100 ° C) for mixed metal cathodes (W / Os) with and without addition of chromium oxide.
- FIG. 4th
- shows a curve of the saturation current for 35 kV / cm as a function of the operating time for mixed metal cathodes (W / Os) with and without addition of chromium oxide.
- FIG. 5
- shows schematically a cross section through a cathode body with two layers and its production from a three-layer sintered body.
FIG. 1 zeigt schematisch den Aufbau einer Vorratskathode mit einer Emissionsfläche 6. Der Kathodenkörper 1 der auch aus zwei oder drei Schichten bestehen kann, wird z.B. durch Pressen einer Pulvermischung (z.B. W + Os + Cr2O3) in den Kathodenhalter 2 (z.B. aus Molybdän) hergestellt. Nach dem Sintern erfolgt das Füllen mit dem Emissionsmaterial (z.B. BaO + CaO + Al2O3) z.B. durch Tränken.FIG. 1 schematically shows the structure of a supply cathode with an
Der Heizer 3 wird z.B. mit Al2O3 4 in einen Topf 5 aus Molybdän eingebettet, der an dem Kathodenhalter 2 befestigt ist.The
FIG. 2 zeigt die Elektronen-Austrittsarbeit (eΦ/eV), deren Wert aus (bei 1000°C gemessenen) Strom-Spannungs-Kennlinien nach bekannten Verfahren ermittelt wurde, in Abhängigkeit von der Kathoden-Temperatur (T in °C).FIG. 2 shows the electron work function (eΦ / eV), the value of which was determined from current-voltage characteristics (measured at 1000 ° C.) according to known methods, as a function of the cathode temperature (T in ° C.).
Bei neu hergestellten Kathoden (sehr kurze Betriebszeit) ist die Austrittsarbeit für Kathoden mit Cr2O3-Zusatz bei tiefen Temperaturen etwa 0,1 eV niedriger als für Kathoden ohne Zusatz, bei hohen Temperaturen noch etwa 0,05 eV.In the case of newly manufactured cathodes (very short operating time), the work function for cathodes with Cr 2 O 3 addition is also low temperatures about 0.1 eV lower than for cathodes without additives, at high temperatures about 0.05 eV.
FIG. 3 zeigt die Änderung der Austrittsarbeit (eΦ/eV) (für 1000°C) während des Betriebs mit (zur Beschleunigung der Alterung) erhöhter Temperatur (1100°C) über der Betriebszeit in Stunden (h). Die Austrittsarbeit für Kathoden mit Cr2O3-Zusatz fällt am Anfang des Betriebs noch etwas ab und bleibt während der Beobachtungszeit (fast 10 000 Stunden) praktisch konstant. Die Austrittsarbeit für Kathoden ohne Zusatz steigt an, sodaß nach 1000 Stunden ihr Wert etwa 0,1 eV höher liegt als bei Kathoden mit Cr2O3.FIG. 3 shows the change in work function (eΦ / eV) (for 1000 ° C) during operation with (to accelerate aging) increased temperature (1100 ° C) over the operating time in hours (h). The work function for cathodes with Cr 2 O 3 addition drops slightly at the beginning of operation and remains practically constant during the observation period (almost 10,000 hours). The work function for cathodes without additives increases, so that after 1000 hours their value is about 0.1 eV higher than for cathodes with Cr 2 O 3 .
FIG. 4 zeigt als Beispiel für die Größe des erreichbaren Stroms die zeitliche Änderung des Sättigungsstroms (Stromdichte j in A/cm2) bei einer Feldstärke von 35 kV/cm über der Betriebszeit t(h). Entsprechend zur Austrittsarbeit (FIG. 3) verhält sich der Sättigungsstrom; er ändert sich für Kathoden mit Cr2O3-Zusatz weniger als für solche ohne Zusatz. Nach längerer Betriebszeit (im Beispiel fast 10000 Stunden bei 1100°C) ist der Sättigungs-Strom für Kathoden mit Cr2O3-Zusatz noch etwa doppelt so groß wie der Strom bei Kathoden ohne Zusatz. (Bei tiefer Temperatur zeigen beide Typen praktisch keinen Abfall).FIG. 4 shows, as an example of the size of the current that can be achieved, the change in saturation current over time (current density j in A / cm 2 ) at a field strength of 35 kV / cm over the operating time t (h). The saturation current behaves according to the work function (FIG. 3); it changes less for cathodes with Cr 2 O 3 addition than for those without addition. After a longer operating time (in the example, almost 10,000 hours at 1100 ° C), the saturation current for cathodes with Cr 2 O 3 addition is still about twice as large as the current for cathodes without addition. (Both types show practically no waste at low temperatures).
Bei einem vorteilhaften Ausführungsbeispiel wird der Chromoxidzusatz dem Sinterkörper des Kathodenkörpers zugesetzt. Dies geschieht zweckmäßig in der Weise, daß dem oder den Pulvern der Metalle der ersten Gruppe und der zweiten Gruppe pulverförmiges Chromoxid (Cr2O3) zugemischt wird, diese Mischung dann gepreßt und dann zu einem porösen Sinterkörper gesintert wird. Der Chromoxidanteil der Pulvermischung beträgt 1-20 Gew.%, vorzugsweise 7-14 Gew.%, insbesondere etwa 10 Gew.%. Bevorzugt bestehen die anderen Pulveranteile aus Wolfram und Osmium, wobei der Wolframanteil zweckmäßig nicht kleiner sein soll, als der Osmiumanteil. Gegebenenfalls kann auf das Metall der zweiten Gruppe, also z.B. Osmium, ganz verzichtet werden.In an advantageous embodiment, the chromium oxide additive is added to the sintered body of the cathode body. This is advantageously done in such a way that powdered chromium oxide (Cr 2 O 3 ) is added to the powder or powders of the metals of the first group and the second group, this mixture is then pressed and is then sintered into a porous sintered body. The chromium oxide content of the powder mixture is 1-20% by weight, preferably 7-14% by weight, in particular approximately 10% by weight. The other powder fractions preferably consist of tungsten and osmium, the tungsten fraction expediently not to be smaller than the osmium fraction. If necessary, the metal of the second group, for example osmium, can be dispensed with entirely.
Der erfindungsgemäße Chromoxidzusatz ist besonders vorteilhaft bei einer Vorratskathode anzuwenden, deren Vorratskörper aus mehreren übereinanderliegenden und zusammengesinterten Sinterschichten besteht, wie sie z.B. in der DE-OS 41 14 856 A1 beschrieben ist. Der dort beschriebene Schichtsinterling besteht mindestens aus zwei Schichten, die aus im wesentlichen gleichen Materialien bestehen. Der gewichtsprozentuale Anteil der Materialien ist jedoch in wenigstens zwei aneinandergrenzenden Schichten unterschiedlich und zwar in der Weise, daß in der einen Schicht der Anteil des Metalles der ersten Gruppe größer ist als der Anteil des Metalles der zweiten Gruppe und in der anderen Schicht der Anteil des Metalles der zweiten Gruppe größer ist als der Anteil des Metalles der ersten Gruppe. Auch bei einem solchen Kathodenkörper mit geschichtetem Sinterling soll zumindest in der die Emissionsoberfläche 6 aufweisenden Schicht Chromoxid vorhanden sein, wobei das Chromoxid im Sinterling enthalten ist.The chromium oxide additive according to the invention is particularly advantageous for use with a storage cathode, the storage body consists of several superimposed and sintered sintered layers, as described for example in DE-OS 41 14 856 A1. The layer sintering described there consists of at least two layers which consist of essentially the same materials. However, the percentage by weight of the materials differs in at least two adjacent layers in such a way that in one layer the proportion of the metal of the first group is greater than the proportion of the metal in the second group and in the other layer the proportion of the metal in the second group is greater than the proportion of metal in the first group. In such a cathode body with a layered sintered body, chromium oxide should also be present at least in the layer having the
Vorzugsweise wird eine solche Vorratskathode mit einem mehrschichtigen Kathodenkörper unter Anwendung eines aus der DE-OS 4 114 856 bekannten Verfahrens hergestellt, bei welchem der Sinterkörper mit einer zusätzlichen Schicht hergestellt wird und diese zusätzliche Schicht nach dem Sintern wieder entfernt wird.Such a supply cathode is preferably produced with a multilayer cathode body using a method known from
FIG. 5 zeigt in der rechten Hälfte einen Querschnitt durch einen Sinterkörper mit einer ersten Schicht 11, einer zweiten Schicht 12 und einer dritten Schicht 13 in einem Kathodenhalter 2. Die erste Schicht ist im wesentlichen aus einem Metallpulvergemisch von mehr als 50 Gew.%, vorzugsweise mehr als 70 Gew.% Wolfram und Rest Osmium hergestellt. Die dritte Schicht 13 ist vorzugsweise genauso zusammengesetzt wie die erste Schicht. Die zweite Schicht 12 ist hergestellt aus einem Gemisch von Wolfram-Metallpulver, Osmium-Metallpulver und ca. 10 Gew.% Chromoxid-Pulver, wobei der Gehalt von Osmium höher ist als in den Schichten 11 und 13 und vorzugsweise mehr als 50 Gew.% beträgt. Die verschiedenen Pulvermischungen werden nacheinander in den Kathodenhalter eingefüllt, unter hohem Druck gepreßt und gemeinsam gesintert.FIG. 5 shows in the right half a cross section through a sintered body with a
Die dritte Schicht 13 und ein Teil der zweiten Schicht 12 bis zu der unterbrochenen Linie werden nach dem Sintern entfernt, z.B. durch Schleifen, so daß ein in der linken Hälfte der Fig. 5 skizzierter zweischichtiger Kathodenkörper mit der die freiliegende Oberfläche der zweiten Schicht bildenden Emissionsoberfläche 6 entsteht. Die Füllung (Imprägnierung) der Metall-Matrix mit dem Emissionsmaterial erfolgt vorzugsweise vor dem Entfernen der dritten und des Teils der zweiten Schicht.The third layer 13 and part of the
Claims (7)
- Dispenser cathode with a dispenser body which comprises a porous sintered body which contains at least one metal of a first group such as W, Mo and Cr and/or a second group such as Fe, Co, Ni, Ru, Rh, Pd, Re, Os, Ir and Pt, is impregnated by an emissive material and to which chromium oxide is added, characterised thereby, that the chromium oxide is added to the dispenser body as component of the porous sintered body.
- Dispenser cathode according to claim 1, characterised thereby, that the sintered body consists substantially of a sintered powder mixture of tungsten, osmium and chromium oxide.
- Dispenser cathode according to claim 2, characterised thereby, that the proportion of tungsten is equal to or greater than the proportion of osmium.
- Dispenser cathode according to one of the claims 1 to 3, characterised thereby, that 1 to 20% by weight, preferably 7 to 14% by weight and in particular about 10% by weight of the chromium oxide is added.
- Dispenser cathode according to one of the claims 1 to 4, characterised thereby, that the sintered body consists of at least two layers which lie one above the other, are sintered together and consist of like materials, however differ in the composition in per cent by weight and of which the top layer contains the emissive surface.
- Dispenser cathode according to claim 5, characterised thereby, that the proportion of the metal of the first group, in particular of the tungsten, in the layer containing the emissive surface is less than the proportion of the metal of the second group, in particular of the osmium.
- Dispenser cathode according to one of the preceding claims, characterised thereby, that the emissive material contains at least two alkaline-earth metal oxides such as CaO, BaO and at least one oxide of a metal of the group IIIa or IIIb of the periodic system such as for example Al2O3.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4408941A DE4408941A1 (en) | 1994-03-16 | 1994-03-16 | Supply cathode |
| DE4408941 | 1994-03-16 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0673051A1 EP0673051A1 (en) | 1995-09-20 |
| EP0673051B1 true EP0673051B1 (en) | 1997-08-13 |
Family
ID=6512957
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP95103216A Expired - Lifetime EP0673051B1 (en) | 1994-03-16 | 1995-03-07 | Dispenser cathode |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5594299A (en) |
| EP (1) | EP0673051B1 (en) |
| JP (1) | JPH07272614A (en) |
| DE (2) | DE4408941A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6054801A (en) * | 1998-02-27 | 2000-04-25 | Regents, University Of California | Field emission cathode fabricated from porous carbon foam material |
| RU2176833C1 (en) * | 2000-11-30 | 2001-12-10 | Закрытое акционерное общество Научно-производственный центр "СОЛИТОН-НТТ" | Electrode material for low-temperature plasma generator |
| WO2006115428A1 (en) * | 2005-04-27 | 2006-11-02 | Vladimir Ivanovich Kapustin | Thermoemitter material for surface ionisation of organic compounds in the air and method for activating a thermoemitter |
| GB2567853B (en) * | 2017-10-26 | 2020-07-29 | Isotopx Ltd | Gas-source mass spectrometer comprising an electron source |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1072753B (en) * | 1953-11-28 | 1960-01-07 | Siemens &. Halske Aktiengesellschaft, Berlin und München | Cathode for electrical discharge vessels and process for their manufacture |
| US2995674A (en) * | 1959-02-27 | 1961-08-08 | Raytheon Co | Impregnated cathodes |
| US3155864A (en) * | 1960-03-21 | 1964-11-03 | Gen Electric | Dispenser cathode |
| DE3017429A1 (en) * | 1980-05-07 | 1981-11-12 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Emission material for impregnating electron tube cathode - with porous sintered matrix, contains aluminium, barium, calcium, strontium and opt. tungsten |
| US4417173A (en) * | 1980-12-09 | 1983-11-22 | E M I-Varian Limited | Thermionic electron emitters and methods of making them |
| DE3122950A1 (en) * | 1981-06-10 | 1983-01-05 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Process for fabricating a dispenser cathode |
| JPS63236239A (en) * | 1987-03-10 | 1988-10-03 | シーメンス、アクチエンゲゼルシヤフト | Dispenser cathode for discharge tube and making thereof |
| US4810926A (en) * | 1987-07-13 | 1989-03-07 | Syracuse University | Impregnated thermionic cathode |
| FR2625364B1 (en) * | 1987-12-23 | 1990-05-04 | Thomson Csf | PROCESS FOR MANUFACTURING AN IMPREGNATED CATHODE AND CATHODE OBTAINED BY THIS PROCESS |
| US5019752A (en) * | 1988-06-16 | 1991-05-28 | Hughes Aircraft Company | Plasma switch with chrome, perturbated cold cathode |
| KR910003698B1 (en) * | 1988-11-11 | 1991-06-08 | Samsung Electronic Devices | Cavity reservoir type dispenser cathode and method of the same |
| KR920009849B1 (en) * | 1990-12-28 | 1992-10-31 | 주식회사 금성사 | Method of manufacturing an impregnated cathode |
| KR930007461B1 (en) * | 1991-04-23 | 1993-08-11 | 주식회사 금성사 | Method of making a dispenser type cathode |
| DE4114856A1 (en) * | 1991-05-07 | 1992-11-12 | Licentia Gmbh | STOCK CATHODE AND METHOD FOR THE PRODUCTION THEREOF |
-
1994
- 1994-03-16 DE DE4408941A patent/DE4408941A1/en not_active Withdrawn
-
1995
- 1995-03-07 DE DE59500487T patent/DE59500487D1/en not_active Expired - Lifetime
- 1995-03-07 EP EP95103216A patent/EP0673051B1/en not_active Expired - Lifetime
- 1995-03-09 US US08/401,728 patent/US5594299A/en not_active Expired - Lifetime
- 1995-03-15 JP JP5625295A patent/JPH07272614A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE59500487D1 (en) | 1997-09-18 |
| JPH07272614A (en) | 1995-10-20 |
| DE4408941A1 (en) | 1995-09-21 |
| US5594299A (en) | 1997-01-14 |
| EP0673051A1 (en) | 1995-09-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE3418403C2 (en) | A method of making a high toughness cermet for use in cutting tools | |
| DE60019682T2 (en) | Porous metal bodies, methods of making the same and metal composites using them | |
| DE3880794T2 (en) | Scandate cathode. | |
| DE4105657C2 (en) | Sliding material and method for its production | |
| DE1015941B (en) | Supply cathode and process for its manufacture | |
| DD209703A5 (en) | METHOD FOR MANUFACTURING A REPLACEMENT CATHODY AND A DELIVERY CATEGORY MADE ACCORDING TO THESE PROCEDURES | |
| DE2635289C2 (en) | Metal carrier plate of the oxide layer of directly heated oxide cathodes and process for their production | |
| EP0512280B1 (en) | Dispenser cathode and method of fabricating same | |
| DE2545119C2 (en) | Self-melting, glass-like resistance mixture for resistance spark plugs | |
| DE2945995A1 (en) | OXIDE-COATED CATHODE FOR ELECTRON PIPES | |
| DE2641884A1 (en) | GAS BONDING DEVICE - A METHOD OF MANUFACTURING A COLOR TELEVISION TUBE USING THIS GAS BINDING DEVICE AND A COLOR TELEVISION TUBE MANUFACTURED BY THIS METHOD | |
| EP0005279B1 (en) | Hot cathode | |
| EP0673051B1 (en) | Dispenser cathode | |
| DE2822665A1 (en) | GLOW CATHODE MATERIAL | |
| DE69026032T2 (en) | Scandate cathode | |
| DE69010241T2 (en) | Scandate cathode. | |
| DE2454569C3 (en) | Reaction cathode | |
| DE1276535B (en) | Vacuum-tight refractory metal-ceramic joint and process for their production | |
| DE68923098T2 (en) | Method of manufacturing a fuel cell. | |
| DE3888882T2 (en) | Process for producing a replacement cathode. | |
| DE2748566C3 (en) | Rotary anode for an X-ray tube and process for its manufacture | |
| DE970707C (en) | Storage cathode, in which the active substance reaches the cathode surface from a closed chamber through the pores of a sintered body | |
| DE2435658C3 (en) | Ceramic-to-metal material | |
| DE2849606C3 (en) | Base metal plate material for directly heated oxide cathodes | |
| DE19618929A1 (en) | Cathode for electron tubes |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT NL |
|
| 17P | Request for examination filed |
Effective date: 19951026 |
|
| 17Q | First examination report despatched |
Effective date: 19960716 |
|
| GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: AEG ELEKTRONISCHE ROEHREN GMBH |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB IT NL |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 19970813 |
|
| GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) |
Effective date: 19970814 |
|
| REF | Corresponds to: |
Ref document number: 59500487 Country of ref document: DE Date of ref document: 19970918 |
|
| ET | Fr: translation filed | ||
| NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
| PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
| 26N | No opposition filed | ||
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: 746 Effective date: 20000522 |
|
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: IT Payment date: 20120327 Year of fee payment: 18 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R082 Ref document number: 59500487 Country of ref document: DE Representative=s name: GERHARD WEBER, DE |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R082 Ref document number: 59500487 Country of ref document: DE Representative=s name: GERHARD WEBER, DE Effective date: 20120911 Ref country code: DE Ref legal event code: R082 Ref document number: 59500487 Country of ref document: DE Representative=s name: BAUR & WEBER PATENTANWAELTE, DE Effective date: 20120911 Ref country code: DE Ref legal event code: R081 Ref document number: 59500487 Country of ref document: DE Owner name: THALES AIR SYSTEMS & ELECTRON DEVICES GMBH, DE Free format text: FORMER OWNER: THALES ELECTRON DEVICES GMBH, 89077 ULM, DE Effective date: 20120911 Ref country code: DE Ref legal event code: R081 Ref document number: 59500487 Country of ref document: DE Owner name: THALES ELECTRONIC SYSTEMS GMBH, DE Free format text: FORMER OWNER: THALES ELECTRON DEVICES GMBH, 89077 ULM, DE Effective date: 20120911 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20130331 Year of fee payment: 19 Ref country code: GB Payment date: 20130318 Year of fee payment: 19 Ref country code: FR Payment date: 20130329 Year of fee payment: 19 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R082 Ref document number: 59500487 Country of ref document: DE Representative=s name: BAUR & WEBER PATENTANWAELTE, DE |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R082 Ref document number: 59500487 Country of ref document: DE Representative=s name: BAUR & WEBER PATENTANWAELTE, DE Effective date: 20130911 Ref country code: DE Ref legal event code: R081 Ref document number: 59500487 Country of ref document: DE Owner name: THALES ELECTRONIC SYSTEMS GMBH, DE Free format text: FORMER OWNER: THALES AIR SYSTEMS & ELECTRON DEVICES GMBH, 89077 ULM, DE Effective date: 20130911 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 59500487 Country of ref document: DE |
|
| GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20140307 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20141128 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 59500487 Country of ref document: DE Effective date: 20141001 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20141001 Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20140331 Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20140307 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20140307 |