Codeposition of titanium dioxide particles from acid copper and zinc sulfate baths

The purpose of this work is to elucidate the dependence of the codeposition of titanium dioxide particles on the kind and the amount of adsorbed metal ion. An acid copper sulfate bath with titanium dioxide particles was mainly used for this investigation. The surface OH group of the titanium dioxide particle interacts with Cu²⁺ in the bath, which results in H⁺ release. This reaction depends both on the concentration of Cu²⁺ and on the pH of the solution. It was found that the amount of codeposited titanium dioxide increased with increasing pH of the bath, which indicates that the amount of codepositing particles depends upon the amount of Cu²⁺ adsorbed on the particle. Relation between the codeposition behavior and the nature of depositing metal ion is also discussed.