Electrodeposition of Ag and Ag-Ni powders in potentiostatic and pulse potential modes

K Ignatova
2013 Bulgarian Chemical Communications   unpublished
The kinetics of electrodeposition and the microstructure of pure Ag and alloyed Ag-Ni powders were investigated depending on the type of electrolyte and conditions for deposition. It was found out that in acid nitrate electrolyte the Ag powders are white after deposition and have a more determined crystal structure. In complex ammonia-nitrate electrolyte grey Ag powders with irregularly shaped particles and higher dispersion are formed. In ammonia-citrate electrolyte the deposited Ag powders
more » ... dark grey to black in color, with typical dendrite structure of particles and susceptible to agglomeration. Each type of Ag powder consists of a single phase, i.e. silver phase with cubic face-centered lattice (fcc). The advantages of ammonia-citrate electrolyte compared to ammonia-nitrate one for obtaining fine dispersed Ag-Ni powders are proved. The use of higher cathode potentials in potentiostatic mode and pulse frequency up to 1000 Hz in pulse potential mode in the ammonia-citrate electrolyte results in decreasing the average size of particles to approximately 1 µm and increasing the content of nickel up to 12-18%.