Codeposition of α‐Alumina Particles from Acid Copper Sulfate Bath

The purpose of this work is to elucidate the factors affecting the codeposition of α‐alumina particles with copper from an acid copper sulfate bath. The effect of current density and particle concentration in the bath on the amount of codeposited α‐alumina were determined. In order to evaluate the surface‐chemical properties of the particles, the zeta‐potential of α‐alumina particles in the plating bath was determined by means of the streaming potential method. The amounts of adsorbed Cu 2+ and from the plating bath were also determined. The amount of codeposited α‐alumina particles was found to be greater than those reported in literature, in spite of the negative zeta‐potential values of α‐alumina. This indicates that the electrostatic interaction between the particles and the cathode is not the essential factor of the codeposition process. It is considered that the amount of adsorbed Cu 2+ on the α‐alumina particle plays an important role in the codeposition behavior.