Production of Composite Electrochemical Coatings with Modified Dispersed Graphite Based on a Silver Matrix

This paper examines the effect of adding modified dispersed graphite (MDG) to a cyanide-rhodanide electrolyte on the formation of composite coatings based on a silver matrix. The modified dispersed graphite was obtained electrochemically in a mixture of sulfuric and nitric acids. X-ray phase analysis revealed that the resulting mixture consisted of 50% oxidized and 50% unoxidized graphite. Energy-dispersive X-ray spectroscopy (EDS) revealed that the carbon content of the composite silver coating increased with increasing concentration of the dispersed graphite phase in the working electrolyte and increasing current density during electroplating. The obtained elemental maps of local distribution indicate that the particles of modified dispersed graphite are uniformly distributed over the entire surface of the silver coating, and their size varies from several micrometers to ~80 μm. Increasing the concentration of the MDG additive in the electrolyte from 2.5 to 10 g/L leads to a decrease in the microhardness of the composite silver coating.