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Glukhova O. E., Krachkovskaya T. M., Petrunin A. А. Predictive evaluation of barium evaporation ratefrom the surface of a porous metal thermionic cathode: A mathematical model based on experimental data for B- and M-type cathodes. Izvestiya of Saratov University. Physics , 2026, vol. 26, iss. 2, pp. 175-184. DOI: 10.18500/1817-3020-2026-26-2-175-184, EDN: QYOLXM
Predictive evaluation of barium evaporation ratefrom the surface of a porous metal thermionic cathode: A mathematical model based on experimental data for B- and M-type cathodes
Background and Objectives: Based on the analysis of experimental studies regarding the evaporation rate patterns of the main component of the active substance – barium – from the surface of B- and M-type cathodes, a methodology for the predictive evaluation of its evaporation rate has been developed. Materials and Methods: The theoretical foundation of this methodology comprises the Langmuir formula for the rate of mass loss and the Clausius-Clapeyron equation. Results: The methodology yields a characteristic set of parameters for a given cathode type: p’0 (pressure), T0 (temperature), and q (activation energy). The effectiveness of the methodology has been demonstrated by predicting the temperature dependence of the barium evaporation rate for several B- and M-type cathodes, with the error in reproducing experimental data not exceeding 15%. New dependencies for the barium evaporation rate G(T) have been obtained for M-type cathodes containing ugleron (a sulfo-adduct of carbon nanoclusters) within the active substance in the concentration range of 0–0.4 wt%. It has been established that the evaporation rate of the active substance decreases with an increase in ugleron concentration. Conclusion: The developed methodology is promising for predicting the application of new nanomaterials in the composition of active substances for various types of thermionic cathodes.
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