350 rub
Journal Science Intensive Technologies №11 for 2014 г.
Article in number:
Physicochemical special features of «scandat» cathode materials
Keywords: «scandat» cathode barium oxide calcium oxide aluminum oxide scandium oxide state diagrams the emission properties
Authors:
I.P. Lee - Ph. D. (Eng.), Head of Department, JSC «Pluton» (Moscow). E-mail: ork@pluton.msk.ru
V.I. Kapustin - Dr. Sc. (Phys.-Math.), Professor, MIREA (Moscow). E-mail: Kapustin@mirea.ru
N.E. Ledentсova - Engineer, JSC «Pluton» (Moscow), Post-graduate Student, MIEM NRU HSE (Moscow). E-mail: nekharitonova@mail.ru
A.D. Silaev - Head of Laboratory, JSC «Pluton» (Moscow), Post-graduate Student, MATI-RSUAT (Moscow). E-mail: silaev_ad@mail.ru
V.S. Polyakov - Head of Laboratory, JSC «Pluton» (Moscow), Post-graduate Student, MATI-RSUAT (Moscow). E-mail: p_vs@list.ru
V.S.Petrov - Ph. D. (Eng.), Associate Professor, Engineer, JSC «Pluton» (Moscow)
Y.Y.Lebedinskiy - Ph. D. (Phys.-Math.), Senior Research Scientist, MIPT (SU) (Dolgoprudny). E-mail: YYLebedinskij@mephi.ru
A.V.Zablotskiy - Research Engineer, MIPT (SU) (Dolgoprudny). E-mail: zalexx@gmail.com
Abstract:
Scandate cathodes have better thermionic characteristics compared to the typical impregnated cathodes but they are less stable and less durable. Therefore, the development of physicochemical mechanisms of scandate cathodes action for optimization of their composition and fabrication is needed. In our analytical research, a scientific hypothesis on a mechanism of effect of scandium in cathode material on its thermionic characteristics was formulated. According to this hypothesis the main roles of scandium in cathode material are the decrease of barium oxide surface barrier due to appearing of cationic vacancies (barium vacancies) and developing of additional donor levels on the barium oxide surface. By high resolution electronic spectroscopy it was shown that if scandium oxide was present in cathode material, electronic levels of barium in barium oxide were broadened. This indicates that in the presence of doping scandium ions barium converts to the state with a broader row of oxidation numbers than in the presence of doping aluminum ions. In turn, this fact suggests that scandium ions are more soluble in barium oxide compared to aluminium ions. This favors formation of cationic vacancies and donor surface states in barium oxide. The paper includes 12 pictures, 3 sheets, and 26 references.
Pages: 40-49
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