High current density and long life nanocomposite scandate dispenser cathode fabrication

Nano Sc₂O₃-doped W powder for use in high current density thermionic cathodes has been made by the sol-gel method with different average particle size: around 72 nm, 146 nm, 272 nm, and 587 nm, respectively. By using these powders, Sc₂O₃-doped tungsten matrices with the nanosize tungsten grains were obtained as discussed in this paper. Sc₂O₃-doped W matrix impregnated cathodes have shown excellent emission properties. A space charge limited current density of 33.3 A/cm² at 1000degC has been obtained by using 587 nm Sc₂O₃-doped W powders.