Cathodic Polarization Behavior of Ag ‐ Al2 O 3 Electrode in Silver Thiocyanate Solution Containing Al2 O 3 Particles

Mechanisms for the codeposition of particles from silver thiocyanate solution have been investigated. The codeposition rate of onto composite coatings was found to increase with slight agitation near the cathode surface and with larger cathodic overvoltages. The actual cathodic current density was smaller, at low overvoltage, for solutions containing than for those without it. However, the opposite was true at high overvoltage. On the basis of the experimental results, it was felt that dispersion particles suppressed the electrodeposition reaction of silver, since the particles were absorbed on the cathode at low overvoltage. Stirring near the electrode surface promoted the reactions.