Electrochemical investigation of the codeposition of SiC and SiO2 particles with nickel

The use of electrochemical impedance spectroscopy (EIS) for the in situ con trol of the electrolytic codeposition of Ni/SiO2 and Ni/SiC was investigate d. An attempt was made to clarify why silica particles hardly codeposit in comparison to silicon carbide particles. It was found that the presence of SiO2 and SiC particles influences the metal deposition process in different ways. SiC particles that are being embedded in the growing metal layer cau se an apparent decrease in the electrode surface area, probably due to bloc king off a part of the surface by partly engulfed particles. In the case of SiO2 particles, which embed in the metal matrix to a very limited extent, no blocking was observed. It was found that the presence of particles in th e solution causes an apparent increase in the electrode surface area, proba bly due to increased surface roughness.