Kiyoshi Takatsu

Investigation of Current Efficiency in Particle Plating

Studies were conducted on the suspension condition of fine particles and on the mechanism of electron transmission between particles in order to determine the conditions under which particle plating can be carried out with high current efficiency and high current density. The following results were obtained: 1) The factor influencing current efficiency most is not the concentration of particles in the suspension (space ratio) but the dispersion of particles or a stationary bed (bed expansion). This suggests that electrons are mainly transmitted between particles by means of contact rather than by collision. 2) When current density per unit of particle surface area is low, current efficiency is extremely poor, and then the current density is comparatively high, current efficiency improves. 3) When the suspension condition is inappropriate, particle plating dose not proceed at all. All that occurs is particle dissolution by bipolar phenomena and dispersion plating on the cathode.