Hydrogen isotopic effect during the graphite high-temperature corrosion in water vapours

Chikhray, Y.; Askerbekov, Saulet; Kenzhina, I.; Gordienko, Yuriy; Bochkov, Vadim; Нестеров, Е. А.; Варламова, Н. В.

doi:10.1016/j.ijhydene.2019.03.013

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…The lack of objective data on the processes of corrosion and degradation in corrosive media opens up broad prospects for researchers to conduct such experiments. Interest in them is due to the possibility of obtaining kinetic curves of the degradation rate, which in the future will make it possible to contribute to the characterization of lithium-containing ceramics for thermonuclear power engineering [21][22][23][24][25]. Also of particular interest is the study of the effect of the presence of two-phase structures on resistance to degradation, since earlier studies indicate that two-phase ceramics have higher strength and durability [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Study of Corrosion Resistance and Degradation Mechanisms in LiTiO2-Li2TiO3 Ceramic

2021

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The interest in lithium-containing ceramics is due to their huge potential as blanket materials for thermonuclear reactors for the accumulation of tritium. However, an important factor in their use is the preservation of the stability of their strength and structural properties when under the influence of external factors that determine the time frame of their operation. This paper presents the results of a study that investigated the influence of the LiTiO2 phase on the increasing resistance to degradation and corrosion of Li2TiO3 ceramic when exposed to aggressive acidic media. Using the X-ray diffraction method, it was found that an increase in the concentration of LiClO4·3H2O during synthesis leads to the formation of a cubic LiTiO2 phase in the structure as a result of thermal sintering of the samples. During corrosion tests, it was found that the presence of the LiTiO2 phase leads to a decrease in the degradation rate in acidic media by 20–70%, depending on the concentration of the phase. At the same time, and in contrast to the samples of Li2TiO3 ceramics, for which the mechanisms of degradation during a long stay in aggressive media are accompanied by large mass losses, for the samples containing the LiTiO2 phase, the main degradation mechanism is pitting corrosion with the formation of pitting inclusions.

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Section: Introductionmentioning

confidence: 99%

Study of Corrosion Resistance and Degradation Mechanisms in LiTiO2-Li2TiO3 Ceramic

2021

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“…Study of thermophysical properties of tin-lithium alloys of various composition were carried out on the TiGrA experimental complex [16,17] under the following conditions: Temperature range of sample heating: from 150 о С to 300 о С; Rate of linear heating of the sample: 10 о С/min; Gas medium composition in the chamber -air. Figure 2 shows a general view of the TiGrA complex.…”

Section: Experimental Technique and Research Conditionsmentioning

confidence: 99%

Determination of thermophysical properties of prototypes of tin-lithium alloy by differential scanning calorimetry

Bochkov

Ponkratov

Nikitenkov

et al. 2022

J. Phys.: Conf. Ser.

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This paper presents a description of research works to determine the thermophysical properties of a tin-lithium alloy with a different percentage of lithium and tin atoms in the alloy. The method of differential scanning calorimetry (DSC) was used for the studies, by which the thermophysical properties of the alloy (temperature of phase transition and enthalpy) were determined. The work was carried out at the TiGrA experimental complex. Studies to determine the enthalpy and temperature of phase transition of prototypes of tin-lithium alloy were carried out in the temperature range from 150°C to 500°C at a heating rate of 10°C/min. The experiments were carried out with a pristine sample of tin (reference) and prototypes of a tin-lithium alloy, the percentage of lithium in which was 20, 25 and 27 at. %. As a result of the work performed, the melting point of the prototypes was determined, which was 224°C and 218°C. The values of the specific heat of fusion (enthalpy) of the investigated alloys were determined, which amounted to 76.5 J/g, 80.7 J/g and 86.3 J/g, respectively.

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“…образцов оловянно-литиевой эвтектики различного состава [11][12][13][14]. Также исследовалась высокотемпературная коррозия графита марки IG-110, используемого в реакторных установках [15].…”

Section: Introductionunclassified

Modeling of Temperature Fields and Gas-Dynamic Flows in the Zone of Placement of Lithium Ceramics Samples During Tga Studies

Chikhray,

Zaurbekova,

Askerbekov

2023

jour

Self Cite

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Modeling of thermogravimetric experiments is an essential tool for understanding the physical and chemical processes that occur during research. This approach helps improve data quality and gain a better understanding of what is going on during thermogravimetric analysis.This paper describes the procedure for modeling a TGA experiment on a Mettler Toledo TGA/DSC 3+ gravimeter, which, together with a mass spectrometer, a humidity generator, and an analytical balance, is part of the TiGRа analytical complex (NNC RK, Kurchatov, Kazakhstan). A description is given of the problem of modeling heat transfer processes in a gravimeter, the process of mass transfer of the reaction gas and reaction products in the gravimeter chamber, as well as the processes of chemical interaction of lithium ceramics with the reaction gas during TGA experiments. Helium with an admixture of oxygen and water vapor was considered as the purge gas.Calculations carried out using the developed model show that at a purge gas supply rate of 100 ml/s, the temperature gradient across the samples will be 2–2.5 ℃, and the gas velocity in the pebble bed will not exceed 0.5 mm/s. It has been established that the concentrations of CO2 carried away by the helium flow above the backfill and in the exit zone (in the sampling zone of the mass analyzer) at different temperatures can differ up to 22 times. Thus, using the developed model, it is possible to calculate the concentrations of CO2, CO, and H2 at any point of the thermogravimeter furnace directly above the test sample, inside and/or outside the pebble bed, in the area of the reaction mixture inlet and in the sampling area of the mass analyzer, etc. Also, if necessary, it is possible to determine the coefficients for recalculating concentrations in different sections of the pebble bed relative to the measured value. Using this model, it is possible to determine the parameters of chemical reactions – the initial concentration of carbon in the pebble bed, the activation energy of the reactions, and the concentration of O2 and H2O impurities in the purge helium, achieving the coincidence of the calculated and recorded curves using a mass analyzer. The developed model has a practical potential for further expansion of its analytical capabilities by refining the list of chemical reactions.

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Hydrogen isotopic effect during the graphite high-temperature corrosion in water vapours

Cited by 7 publications

References 13 publications

Study of Corrosion Resistance and Degradation Mechanisms in LiTiO2-Li2TiO3 Ceramic

Study of Corrosion Resistance and Degradation Mechanisms in LiTiO2-Li2TiO3 Ceramic

Determination of thermophysical properties of prototypes of tin-lithium alloy by differential scanning calorimetry

Modeling of Temperature Fields and Gas-Dynamic Flows in the Zone of Placement of Lithium Ceramics Samples During Tga Studies

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