Protsenko V. Multistage electrochemical processes in metals electrode-position involving stable intermediates

The subject of investigation: multistage electrochemical reactions with consecutive charge transfer. Purpose of investigation: developing the theory of multistage electrochemical reactions and establishing the main factors of predicted influence on the metal electrodeposition processes with participation of stable intermediates. Methods of investigation: stationary, cyclic and inversion voltammetry; method of rotating disc electrode; photocolorimetry; potentiometry; X-ray photoelectron spectroscopy; glow discharge spectroscopy; X-ray diffraction; small angle X-ray diffraction; measuring the micro-hardness of deposits; tribotechnical tests; optical microscopy and scanning electron microscopy. Theoretical and practical results: kinetic models of multistage electrochemical reactions with possible transfer of stable intermediates into balk electrolyte have been developed and comprehensively analyzed; quantitative dependences between ideal, real and formal activation energies have been established; reaction schemes of iron and chromium electrodeposition have been proposed; electrolyte is proposed which allows depositing high-quality nanocrystalline Cr-C alloy coatings. The novelty of proposition and results: a theory of generalized variables has been logically applied for the first time for characterization of kinetics of electrochemical reactions; a universal system of dimensionless complexes has been developed which permits describing kinetics of multistage reaction of metal electrodeposition with participation of stable intermediates; for the first time, a new principle for combining of the activation energies of successive stages in electrochemical transformation has been formulated; for the first time, a possibility of purposeful influence on the chromium and iron electrodeposition has been shown, by means of controlled change in composition and colloidal-chemical properties of near-electrode layer; a mechanism of Cr-C alloy electrodeposition has been suggested; according to this mechanism, inclusion of carbon into deposits structure occurs via the mechanism of chemical redox interaction between active chromium ad-atoms and adsorbed organic molecules. Scope of applying: results of the thesis are essential for electrochemistry theory.