Kravchenko O. Thermoelectric properties of Fe-C composite films

The dissertation is devoted to obtaining thermodynamic information and kinetics of redox reactions in Fe-C composite films. The dissertation establishes the conditions for increasing the entropy and enthalpy parameters of the components of the Fe-C composition and composite films. The relationship between entropy and enthalpy of oxidative reactions of constituent mixtures, chemical nature of electrolyte, electrochemical and thermoelectric properties of non-isothermal systems based on iron-carbon composite films is proved. The influence of high values of positive enthalpy on the increase of EMF of the electrochemical system based on Fe-C composite films is shown. The presence of reducing agents (graphite and its oxidized forms) on the surface of particles of iron and salts with reducing properties in the electrolyte affects the redox transformations of the entire system and increases the entropy by 2 orders of magnitude. The influence of alkali concentration on entropy change in non-isothermal systems with Fe-C composite films was established, highly concentrated alkaline solutions with high viscosity have low negative entropy (from - 62 to - 681 JM / K), and dilute solutions have high positive entropy ( from 1000 to 7790 JM / k). Measurements of thermal effects under external loading in electrochemical systems with composite films showed that the use of insulating impurities in the electrolyte reduces EMF by 3 times relative to alkaline electrolytes, but increases its retention time by 8 times due to slow heat separation and entropy change.