Patterns of Electrophoresis of Colloidal Solutions with a Metallic Dispersed Phase on the Example of Silver

Experimental data on the patterns of electrophoresis of a colloidal silver solution in an aqueous dispersion medium and the parameters of metal particles deposited at the cathode have been obtained. It was found that no coagulation occurred during electrophoresis. The silver particle size increases at the cathode itself due to diffusion processes. As a result, the silver particles at the cathode surface have a significant thickness, far from the monolayer of atoms. The rate of Ag accumulation at the electrode decreases with increasing duration of electrophoresis. While the rate of movement of colloidal particles to the electrode remains constant. The formation of a coating on the electrode surface is a heterogeneous process consisting of a kinetic act. This act is the adsorption of colloidal silver particles and the growth of the latter by diffusion. During electrophoresis, the particles approach the electrode and are adsorbed on it under the action of significant Coulomb forces. When estimating the growth rate of colloidal particles on an electrode, it should be borne in mind that the diffusion coefficients for nanoscale bodies are orders of magnitude greater than for a large amount of matter. In the initial periods, silver particles are deposited at the nickel cathode, and then on the surface of the silver released earlier. The patterns of deposition are changing including the act of adsorption of colloidal silver particles at the electrode. It has been experimentally established that the mass of the substance isolated at the cathode, depending on the amount of electricity passed, is approximated by a straight line in accordance with Faraday’s law. The proportionality coefficient for electrophoresis of a colloidal Ag solution under experimental conditions is an order of magnitude higher than the electrochemical coefficient for silver. It is shown that there is an increase in the amount of Ag at the electrode with an increase in the concentration of the colloidal solution. This illustrates the increasing role of molecular diffusion in the electrophoresis process.