PREPARATION OF VARIOUS OXIDE-FILMS BY AN ELECTROPHORETIC DEPOSITION METHOD - A STUDY OF THE MECHANISM

The electrification mechanism of an oxide particle in a bath was analyzed. The zeta-potentials of various oxide particles in an acetone bath were found to be positive. The data suggested that H+ ions are generated in an acetone bath containing a small amount of added I-2 and H2O by the keto-enol equilibrium reaction and then adsorbed on the oxide resulting in positively charged particles. The adsorption of H+ ions was assumed to be of the type of mono-molecular adsorption. Moreover, the electrodeposition flocculation mechanism for the particle was also investigated. On the basis of a relation of electrophoretic current with depositing time well described by the Cottrell equation, it was suggested that the electrochemical reaction proceeds on the cathode substrate surface and that the rate-determining step arises from the diffusion of H+ ions in the deposited film.