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Electronic surface and volume structure of oxide cathode materials for MW devices

Keywords:

V.I. Kapustin – Dr. Sc. (Phys.-Math.), Professor, Moscow State University of Information Technologies, Radio Engineering and Electronics (MIREA). E-mail: kapustin01@mail.ru Lee I P – Ph. D. (Eng.), Deputy Director, JSC «Pluton» (Moscow) V.I. Svitov – Ph. D. (Eng.), Professor, Moscow State University of Information Technologies, Radio Engineering and Electronics (MIREA) A.V. Shumanov – Head of Laboratory, JSC «Pluton» (Moscow) A.V. Turbina – Process Engineer, JSC «Pluton» (Moscow) A.K. Zakharov – Ph. D. (Eng.), Professor, Moscow State University of Information Technologies, Radio Engineering and Electronics (MIREA)


The production of vacuum microwave devices realized currently by many enterprises, including Open Joint Stock Company «Pluton», uses porous metal cathodes based on tungsten sponge impregnated with barium aluminate-calcium composition BaO•2,5•0,4 CaO•Al2O3. At the same time, any adequate physical and chemical models of structure formation of such materials at the nanoscale level does not exist yet. Methods of optical absorption spectroscopy and characteristic electron energy losses spectroscopy is applied for the structure of the electronic levels of the oxygen vacancy and electron concentration in the oxide of barium investigation, which is the main emission-active component of porous metal and «scandate» cathodes for microwave devices. The decoding of the EEL spectra for porous metal and «scandate» cathodes is carried out. The values of electron concentrations in barium oxide for porous metal and «scandate» cathodes are calculated. The results of the calculation show that for impregnated tungsten matrix oxide phase oxygen vacancies concentration in «scandate» cathode is 1.62 times less than in porous metal cathode. This is due to higher thermal stability of barium scandate in comparison with the aluminate. Electronic structure of standard porous metal and «scandate» cathode investigated shows two factors of influence of scandium on the improvement of emission properties «scandate» cathode compared to porous metal cathode. This may allow to formulate a physical and chemical model of «scandate» cathode functioning, which is still absent for 40 years after its invention.
References:

 

  1. Amelicheva K.A., Belova I.K., Bondarenko G.G.,Korzhavyi A.P.On increasing the lifetime of tungsten-based cathode materials // Russian metallurgy (Metally). 2003. № 4. P. 106−113.
  2. Djubua B.CH., Polivnikova O.V. O nekotorykh osobennostjakh i problemakh sovremennykh ehffektivnykh katodov // EHlektronnaja tekhnika. Ser. 1. SVCH-tekhnika. 2013. № 4(519). S. 187−190.
  3. Djubua B.CH., Kultashev O.K., Polivnikova O.V. EHmissionnaja ehlektronika, nanotekhnologija, sinergetika (k istorii idejj v katodnojj tekhnologii) // EHlektronnaja tekhnika. Ser. 1. SVCH-tekhnika. 2008. № 4 (497). S. 3−22.
  4. Schoenbeck Laura. Investigation of reactions between barium compounds and tungsten in a simulated reservoir hollow cathode environment // In Partial Fulfillment Of the Requirements for the Degree Master of Science in Materials Science and Engineering. GeorgiaInstituteofTechnology. February 2005. 118 r.
  5. Gartner G., Geintter P., Ritz A. Emission properties of top-layer scandate cathodes prepared by LAD // Appl. Surf. Sci. 1997. № 111. P. 11−17.
  6. Kapustin V.I. Raschet temperaturnojj zavisimosti raboty vykhoda okisi barija // Izvestija AN SSSR. Ser. Fizicheskaja. 1991. T. 55. № 12. S. 2455−2458.
  7. Kapustin V.I. Fiziko-khimicheskie osnovy sozdanija mnogokomponentnykh oksidsoderzhashhikh katodnykh materialov // Perspektivnye materialy. 2000. № 2. S. 5−17.
  8. Li I.P., Kapustin V.I., Svitov V.I.i dr.Struktura ehlektronnykh urovnejj kislorodnykh vakansijj v okside barija // EHlektronnaja tekhnika. Ser. 1: SVCH-tekhnika. 2015. № 2(525). S. 45−58.
  9. Zalm P. Thermionic cathodes // Adv. InElectronicsandEl. Phys. Acad. Press. N.Y.–London. 1968. V. 25. P. 211−272.
  10. Nikonov B.P., Bejjnar K.S. Termoehlektronnaja ehmissija oksidnogo katoda v potoke barija // Radiotekhnika i ehlektronika. 1970. T. 15. № 6. S. 1272−1282.
  11. Mott N., Dehvis EH. EHlektronnye processy v nekristallicheskikh veshhestvakh / Per. s angl. M.: Mir. 1974. 472 s.
  12. JAng M. Optika i lazery, vkljuchaja volokonnuju optiku i opticheskie volnovody / Per. s angl. M.: Mir. 2005. 541 s.
  13. Kireev P.S. Fizika poluprovodnikov. M.: Vysshaja shkola. 1975. 584 s.
  14. SHulman A.R., Fridrikhov S.A. Vtorichno-ehmissionnye metody issledovanija tverdogo tela. M.: Nauka. 1977. 552 s.
  15. Lazarev V.B., Sobolev V.V., SHaplygin I.S. KHimicheskie i fizicheskie svojjstva prostykh oksidov metallov. M.: Nauka. 1983. 240 s.

 

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