EP 0794548 A1 19970910 - Thermionic cathode and manufacturing method
Title (en)
Thermionic cathode and manufacturing method
Title (de)
Thermionische Kathode und Verfahren zu ihrer Herstellung
Title (fr)
Cathode thermoionique et son procédé de fabrication
Publication
Application
Priority
FR 9602743 A 19960305
Abstract (en)
A thermionic cathode, for an electron tube, includes a substrate (12) of refractory metal, a compound (14) of an element which forms the single emission layer (18) and a reducing agent (16) which reacts with the compound (14) at the cathode operating temperature to release the emission layer-forming element. The novelty is that the compound is selected from rare earth zirconates, hafnates, aluminates and berylates. Preferably, the compound (14) is neodymium zirconate, lanthanum zirconate, cerium aluminate or a mixture of rare earth compounds and the reducing agent comprises one or more refractory metal carbides. Also claimed is the production of the above cathode by (a) mixing and melting a metal oxide powder and one or more rare earth metal oxide powders under vacuum or hydrogen to produce the compound (14); and, after cooling to the solid state, (b) crushing and grinding to obtain a powder of certain particle size.
Abstract (fr)
L'invention concerne les cathodes thermoioniques pour tubes électroniques comprenant un matériau comportant un substrat (12), un composé (14) d'un élément faisant monocouche (18) émettrice, choisi parmi les zirconates de terres rares, les hafnates de terres rares, les aluminates de terres rares, les bérylates de terres rares et un agent réducteur (16) qui à la température de fonctionnement de la cathode réagit avec le composé (14) libérant l'élément faisant monocouche (18). Application notamment aux tubes électroniques à grille. <IMAGE>
IPC 1-7
IPC 8 full level
H01J 1/14 (2006.01)
CPC (source: EP US)
H01J 1/14 (2013.01 - EP US)
Citation (search report)
- [A] US 1794298 A 19310224 - ALEXANDER JUST
- [A] GB 182817 A 19230809 - DRAHTLOSE TELEGRAPHIE GMBH
- [A] DE 581423 C 19330727 - AEG
- [A] EP 0210805 A2 19870204 - MITSUBISHI ELECTRIC CORP [JP]
- [A] US 2218381 A 19401015 - HENRICUS GOOSKENS
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0794548 A1 19970910; EP 0794548 B1 20030115; DE 69718363 D1 20030220; DE 69718363 T2 20031016; FR 2745951 A1 19970912; FR 2745951 B1 19980605; US 5828165 A 19981027
DOCDB simple family (application)
EP 97400472 A 19970228; DE 69718363 T 19970228; FR 9602743 A 19960305; US 79669497 A 19970304