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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 40 A/cm2 at 850°C, and 170 A/cm2 at 1050°C have been obtained by using 300-500 nm Sc2O3-doped (5.0 wt.%) W powders. Life testing is ongoing with a continuously pulsed loading of 50 A/cm2 at 1050°C after >; 104 hours. The machined cathode made from 1-2 micron size Sc2O3-doped W powder can reach 160 A/cm2 at 1050°C during pulsed operation. The CW cathode testing is being developed for practical application.