I. B. Murashova

Analysis of growth dynamics of dendrite copper deposit in copper sulfate solutions under the galvanostatic conditions

It is shown that, under certain conditions, the dynamics of dendrite copper deposit formation in the galvanostatic electrolysis may be analyzed using the model of cylindrical electrode, which was developed for the systems with a single cathodic reaction. The model enables one to estimate the structural parameters of the deposit (the radii of dendrite tips at the growth front rtip and their location density N). The deposit growth dynamics was studied experimentally in the laboratory conditions by combining the recording of electrical parameters with video recording of dendrite deposit growth. An analysis of spectral density of measured chronopotentiograms is proposed as an additional way of following the formation dynamics of dendrite deposit, which is meant for the production of powder with prescribed structure.

Dependence of metal contact exchange dynamics on electrochemical parameters of electrode processes

Effect of kinetic parameters of electrode processes on the growth dynamics and structural characteristics of the friable metal deposit, which forms via its contact deposition from an aqueous solution, is studied. A model concept is based on the electrochemical processes proceeding at the metal/solution interface. Dependences of the deposition dynamics and deposit characteristics on the exchange currents of depositing and dissolving metals and on the hydrogen exchange currents at the surfaces of both metals are studied.

Growth dynamics and structural variations of a friable metal deposit during its contact deposition from aqueous solutions

A model is proposed for describing dynamics of contact exchange of metals, which takes into account the side process of hydrogen evolution. The contact exchange dynamics and structural characteristics of the deposit are considered as functions of the concentration of ions that undergo reduction in solution and the cementation EMF. The consideration makes allowance for different densities of microelements and the effect of the solution stirring by hydrogen evolving concurrently.

Kinetic Parameters of Silver Electrodeposition from Nitrate Melts

The system Ag/KNO3–NaNO3–AgNO3is studied in an open bath in air by various experimental methods. The limiting diffusion currents of the silver electrodeposition are determined by a galvanodynamic method at various linear current sweep rates. The diffusion coefficient of Ag+ions in equimolar KNO3–NaNO3melt is determined by a potentiodynamic method at linear potential sweep. The exchange currents on a silver support are determined by the method of two current pulses.

Structural Changes in Dendrite Deposits during Galvanostatic Electrolysis: A Calculation

Modeling concepts on the growth dynamics of dendrite deposits are used to design a technique for calculating distributions of a dendrite deposit by its structural parameters (radius of a dendrite apex raand density of distribution of growing apices at the deposit growth front). The radistribution correlates with that of the dry powder by particle size. The reciprocal of the average density of apices distribution correlates with the filling density of the dry powder. The model comprises a set of differential equations that describe time variations in the dendrite deposit height, ra, the kinetic density of the metal reduction current at apices, and the hydrogen discharge current density. The equations are solved by numerical integration inside the Mathcad Plus 6 package. The growth dynamics and structural characteristics of a growing deposit are calculated as functions of the metal ion concentration in solution and the hydrogen exchange current.

Modeling the Cementation Dynamics in Aqueous Solutions in the Absence of Hydrogen Evolution

A modeling description of the process of deposition of a nobler metal from an aqueous solution, which involves no hydrogen evolution, is considered. On the basis of the balance between anodic and cathodic currents and with use made of the idea about a mixed control of the metal reduction on the growing-nuclei tips, a set of differential equations is constructed, which is solved by the Runge–Kutta method in the Mathcad Plus 6 format. Examples of the cementation dynamics at different balance between exchange currents of components and different solution depletion rates by ions of the deposited metal are considered.

Experimental study of contact plating of metals from aqueous solutions

Experimental data on the contact displacement of metals from aqueous solutions are shown. Experimental chronopotentiograms are compared with those calculated based on an earlier proposed model.

Dynamics of Electrocrystallization of Silver Dendrites from a Nitrate Melt at a Constant Area of the Growth Front of the Deposit

A modeling technique for calculating the growth dynamics of dendrite fibers of silver from a nitrate melt is proposed. The area of the growth front of a dendrite deposit is maintained constant by continuously lifting the cathode from the melt. The model is based on the notion about a predominantly diffusion control of the metal discharge at the tops of dendrites that form the deposit growth front. The current distribution over the surface of growing dendrites is calculated using a statistical description of structural features of the fibers.