Study On The Rare Earth-Molybdnum Electronic Emission Materials And Their Application

Based on the former study of our research group, the research on the secondary emission properties of rare earth molybdenum materials was deeply studied in this paper. Rare earth molybdenum secondary emission materials were processed by powder metallurgy and the secondary emission properties the cathode samples were studied. Rare earth oxide molybdenum secondary emission material sample was firstly processed by Spark Plasma Sintering (SPS) method and its secondary emission properties were studied. The secondary emission theory of rare earth molybdenum emission materials was studied and the relationship of materials structure and their secondary emission properties was also studied in this paper. The materials composition, microstructure, granularity distribution, surface analysis and the element analysis of the body materials were studied through XRD, SEM, TEM, AES and Laser granularity analysis Jupiter. The mix powder of rare earth oxide molybdenum was processed by resolution doping method and Hydrogen reduction method, the sintered material which was applied in 2055-type magnetron was processed by isostatic press with pressure 200 Mpa/cm2 and Hydrogen circumstance resistance furnace. The emission experiment of this new kind of cathode materials in magnetron was performed.The study showed that the maxim secondary emission coefficient of rare earth molybdenum cathode materials was 2.45, which meet the requirement (>2.0) of magnetron to the cathode materials. The materials sintered by SPS have many advantages such as fine crystal unique distribution of rare earth element, which makes the rare earth element easier to enrich on the materials surface, and the secondary emission coefficient is improved. A new kind of cathode materials applied in high power magnetron was invented which can replace the traditional cathode materials. The study showed that a rare earth oxide thin film of 5 um formed on the surface of the materials sintered by SPS after activated at 1600C, and its secondary emission coefficient was 3.84. However, as a kind of ceramic, the rare earth oxide molybdenum cathode materials break easily on the surface.The rare earth molybdenum cathode newly processed was put into 2055 type 5cm magnetron. The result of the emission experiment showed that such magnetron could meet the oscillation requirement of 2055 type magnetron and could output the power, which was similar with that of the Ba-W cathode. The thermionic emission ability of rare earth oxide molybdenum should be bettered and its frequency spectrum should be improved. The disposing regulation must be improved when it was applied in magnetron and the life test of rare earth molybdenum should be performed.