Title :
17.5: High current density and long life nanocomposite scandate dispenser cathode fabrication
Author :
Zhao, Jinfeng ; Li, Na ; Li, Ji ; Barnett, Larry ; Banducci, Mike ; Gamzina, Diana ; Luhmann, N.C., Jr.
Author_Institution :
Dept. of Appl. Sci., Univ. of California-Davis (UCD), Davis, CA, USA
Abstract :
Sc2O3-doped W powder for use in high current density thermionic cathodes has been made by the sol-gel method with different particle sizes. Sc2O3-W matrix cathodes have been prepared from these powders, and have shown excellent emission properties. A space charge limited current density of 80 A/cm2 at 1150°C, 50 A/cm2 at 1050°C have been obtained by using 500 nm Sc2O3-doped W powders. Life testing is ongoing with a continuously pulsed loading of 50 A/cm2 at 1050°C after 5448 hours. The maximum current density of the cathode made from 1-2 micro size Sc2O3-doped W powder can reach 106 A/cm2 at 1150°C.
Keywords :
current density; elemental semiconductors; life testing; nanocomposites; particle size; scandium compounds; semiconductor doping; sol-gel processing; space charge; thermionic cathodes; tungsten; Sc2O3; W; current density thermionic cathodes; emission property; life testing; matrix cathodes; nanocomposite scandate dispenser cathode fabrication; particle sizes; pulsed loading; size 500 nm; sol-gel method; space charge; temperature 1050 C; temperature 1150 C; time 5448 hour; Cathodes; Current density; Fabrication; Life testing; Powders; Scanning electron microscopy; Temperature; Tungsten; User centered design; Vacuum systems; Nanosize; Sc2O3-doped W; current density;
Conference_Titel :
Vacuum Electronics Conference (IVEC), 2010 IEEE International
Conference_Location :
Monterey, CA
Print_ISBN :
978-1-4244-7098-3
DOI :
10.1109/IVELEC.2010.5503439
