Yarygin V.I., Тulin S.M.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
The article discusses the experimental results
of a comprehensive research of polycrystalline niobium electrodes in a laboratory
thermoemission thermal-to-electrical converter (TIC), modified by large-dose
implantation of oxygen ions (fluence ~1018 ion/cm2). It
was found by the methods of complex analysis that the activation annealing of
the Nbimp reference sample/TIC electrodes causes changes in the crystallographic structure of the Nbimp
electrodes with the formation on the emitter and collector surface of TICs
(polycrystalline in the initial state) of a stable electronic system Nb-O of
the type Nb6O suboxide with coarse-grained texture (110) with a
grain size of 30–100 microns and a
depth of oxygen up to 500–700
angstroms. The oxygen concentration on the surface of Nbimp
electrodes is 4–5 at. %, which is
an order of magnitude higher than the natural content of dissolved oxygen in
the initial polycrystalline niobium. Thermionic measurements in a laboratory
TIC established that the modification of Nbimp electrodes causes a
significant improvement in the emission-adsorption characteristics of TIC with
an Nbimp – Nbimp
electrode pair.
Within the framework
of a consistent physical model, the article examines the relationship between
the properties of modified Nbimp electrodes with a highly efficient
process of low-temperature thermionic conversion with an attractive barrier
index efficiency (2±0.06 eV) and electrode efficiency ~11% (at an emitter temperature ~1600
K).
1.
Stakhanov I.P., Stepanov A.S., Pashchenko V.P., Guskov Yu.K. Plazmennoye termoemissionnoye preobrazovaniye
energii. [Plasma
thermionic energy conversion].
Moscow, Atomizdat Publ., 1968. 392 p.
2.
Pupko V.Ya. Istoriya rabot po letatel ' nym apparatam na yadernoy energii dlya kosmicheskikh i aviatsionnykh ustanovok v GNTS RF – FEI. [History of work on nuclear powered aircraft for space and aircraft
installations at the SSC RF – IPPE]. Obninsk, IPPE Publ., 2002. 72 p.
3.
Yarygin V.I. Yadernaya energetika pryamogo preobrazovaniya v kosmicheskikh missiyakh XXI v. [Nuclear power of
direct conversion in space missions of the XXI century]. Izvestiya vuzov. Yadernaya energetika, 2013, no. 2, pp. 5–23.
4.
Yarygin V.I., Ruzhnikov V.A., Sinyavskiy V.V. Kosmicheskiye i nazemnyye yadernyye energeticheskiye ustanovki pryamogo preobrazovaniya energii . [Space and Terrestrial
Nuclear Power Plants for Direct Energy Conversion. Monograph]. Moscow, NRNU MEPHI Publ., 2016. 364 p.
5.
Yarygin V.I. Elektrodnyye materialy
termoemissionnykh preobrazovateley energetiche-skikh ustanovok razlichnogo
naznacheniya. Avtoreferat diss. dokt. tekhn. nauk [Electrode materials of thermoemission
converters of power plants for various purposes. Dr. tech. sci. diss. abstract. Obninsk, 1999.
6.
Hatsopoulos G.N., Gyftopoulos E.P. Thermionic
Energy Conversion. Volume 1: Processes and Devices.
The MIT Press Cambridge, Massachusetts, England, 1973. 265 p.
7.
Yarygin D.V., Mironov V.S., Yarygin V.I., Tulin
S.M. Termoemissionnyy preobrazovatel' s vysokimi elektricheskimi
kharakteristikami na osnove metall-kislorodnoy sistemy na kollektore [Thermionic converter with high electrical
characteristics based on a metal-oxygen system on a collector]. Atomnaya
energiya – Atomic Energy, 2000, vol. 89, no. 1, pp. 39–48.
8.
Vybyvanets V.I., Gontar A.S., Eremin S.A. et al. Bazovyy elektrogeneriruyushchiy kanal
dvukhrezhimnykh termoemissionnykh YAEU. Nauchno-tekhnicheskiye problemy
razrabotki i sozdaniya [Basic thermionic fuel element of dual-mode thermionic nuclear power plants.
Scientific and technical problems of development and co-building]. Trudy
Mezhdunarodnoy konferentsii “Yadernaya energetika v kosmose – 2005” [Proc. of the Int. Conf. “Nuclear Power
Engineering in Space – 2005”]. Moscow – Podolsk,
March 1–3, 2005, vol. 1, pp. 79–82.
9.
Lovchikov M.B., Yarygin V.I. Matematicheskoye
modelirovaniye protsessa ispareniya vol'frama v gazovoy smesi CO+CO2 pri vysokikh temperaturakh [Mathematical modeling of the evaporation process of tungsten in a CO+CO2
gas mixture at high temperatures]. Sbornik dokladov mezhdunarodnoy
konferentsii po yadernym energeticheskim ustanovkam NPES-91 [Proc. of the Int. Conf. on Nuclear Power
Plants NPES–91]. Sukhumi,
1991, vol. 2, pp. 152–160.
10. Kokosadze T.S., Tsakadze L.M., Tskhakaya V.K. Issledovaniye
implantirovannogo ionami kisloroda polikristalla niobiya v kachestve elektrodov
termoemissionnogo preobrazovatelya [Investigation of niobium polycrystal implanted with oxygen ions as
electrodes of a thermionic converter]. Zhurnal tekhnicheskoy fiziki – Technical
Physics, 1986, no. 5, pp. 929–931.
11. Moyzhes B.Ya., Tsakadze L.M. Kollektornyye
materialy dlya nizkotemperaturnykh TEP [Collector materials for low-temperature TIC]. Sbornik
tezisov dokladov otraslevoy yubileynoy konferentsii “Yadernaya energetika v
kosmose” [Collection of Abstracts of the Branch Anniversary Conference “Nuclear Power in Space”].
Obninsk, 1990, part 1, 117 p.
12. Bykovskiy Yu.A., Nevolin V.N., Fominskiy V.Yu. Ionnaya i lazernaya implantatsiya metallicheskikh materialov [Ionic and laser
implantation of metallic materials]. Moscow,
Energoatomizdat Publ., 1991. 240 p.
13. Yarygin V.I. Fizicheskiye osnovy
termoemissionnogo preobrazovaniya energii. Chast' 2. Metody issledovaniya,
tekhnika izmereniy kharakteristik i ispytaniy elektrodnykh materialov. Uchebnoye posobiye [Physical
foundations of thermionic energy conversion. Part 2. Research methods,
technique for measuring characteristics and testing of electrode materials. Textbook]. Obninsk, IATE Publ., 2006. 64 p.
14. Andriashin A.V., Meleta E.A., Mironov V.S., Yarygin V.I. Bazovyy kompleks apparatnykh, metodicheskikh i programmnykh sredstv
dlya provedeniya eksperimental'nykh issledovaniy laboratornykh TEP [The basic complex of
hardware, methodological and software tools for experimental studies of
laboratory TIC]. Sbornik «Izbrannyye trudy FEI» [IPPE Selected Proceedings]. Obninsk, IPPE Publ., 1996. Pp. 69–76.
15. Eksperimental'naya baza otrasli v Gosudarstvennom nauchnom tsentre
Rossiyskoy Federatsii – Fiziko-energeticheskiy institut imeni A.I. Leypunskogo [Experimental base of the
industry in the A.I. Leipunsky State Scientific Center of the Russian
Federation – Institute for Physics and Power Engineering]. Obninsk, IPPE Publ., 2005. 88 p.
16. Fomenko V.S. Emissionnyye svoystva materialov. Spravochnik. [Emission properties of materials. Handbook]. Kiev, Naukova Dumka Publ., 1981. 338 p.
