Kryshtop I. Kinetic and thermodynamic peculiarities of the initial stages of zinc electrocrystallization

Investigation of the charge transfer and crystallization stages of the processes of nuclei formation and growth of zinc phases in zincate solutions is the object of the investigation. Based on galvanostatic and potentiostatic experiments a model of formation of zinc nuclei from pure solutions and those containing the additive of polymeric tetraalkylammonium salt on an isotropic electrode is proposed and justified. This model accounts for the connection of thermodynamic and kinetic patterns of the process with the crystallographic inhomogeneity of the electrode. For potentiostatic conditions the summands of overpotential of transition and crystallization for the stage of reaching the critical supersaturation are determined. The local rate of the potentiostatic phase formation at an arbitrary point of the electrode process is calculated and the concept of natural dispersion of the values of the local nucleation rate is confirmed. The galvanostatic transient potential method is used to study the influence of the UPD-OPD transition on the formation of zinc monolayer on an iron electrode. It is shown that electrocrystallization in the region of supersaturation in the system occurs without the stage of phase formation and is interpreted as the development of sites of growth, formed during the deposition of surface alloy Zn-Fe in the UPD region. Based on these data, an electrochemical method of low temperature degreasing of steel products is proposed.