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Different average diameter matrix powders are used in the preparation of the scandate dispenser cathode. Based on a series of techniques such as pressing, sintering and impregnating, the scandate dispenser cathode samples are gained. The results show that: the cathodes made of the different average diameter powders which D(5,0) are 0.45μm, 1.3μm, 2.2μm exhibit excellent performance. The pulse emission...
In this paper, the polycrystalline CexPr1-xB6 (0≤x≤0.6)) bulks were successfully fabricated by spark plasma sintering (SPS). A lot of experiments are conducted to testing the mechanical and emission properties. The technological applications parameters are following: the sintering temperature is 1450°C, the sintering pressure is 50 MPa and the holding time is 5 min. The maximum pulse thermionic emission...
Nanocomposite Sc2O3-added tungsten dispenser cathodes are being developed for a 220 GHz sheet beam TWT (SBTWT) and were tested in Cathode Life Test Vehicles (CLTV) with a Pierce gun configuration under CW mode. In CLTV #1, owing to a perveance issue (there is a 100 micron gap between the focus electrode and cathode emission surface), 10 A/cm2 dc current density can be achieved at practical temperature...
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...
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...
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...
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