Aluminum electroplating of a Cu substrate was conducted at 333 K in an EmImCl-AlCl3 ionic liquid containing 1,10-phenanthroline using current pulse electrolysis with charge density of 57.9 C cm－2. A difference was found in the Al-electroplated film thickness of more than 20 μm between the center and edge parts, as revealed by scanning electron microscope observations. Supporting electrodes were proposed to alleviate the current concentration at the specimen edge. When using a supporting electrode placed around the specimen, the difference in film thickness between the center and edge parts was reduced from 20 μm to 3 μm. Use of the supporting electrode produced a uniform Al-electroplated film formed on the ABS resin substrate covered with the Cu film. For the Al-electroplated film, anodic oxidation treatment and color treatment with pink, blue, and orange was attempted. Results showed that color alumite treatment is possible for Al-electroplated film.
This study characterized the adsorption of cationic surfactants on a model metal substrate（gold）and assessed their suppressive effects on copper electrodeposition. Adsorption was characterized using a quartz crystal microbalance with dissipation monitoring（QCM-D）and ellipsometry for the cationic surfactants used in this study: hexadecyltrimethylammonium bromide（HTAB or CTAB）, tetradecyltrimethylammonium bromide（TTAB）, and dodecyltrimethylammonium bromide（DTAB）. The electrodeposition suppressive effects were assessed using linear sweep voltammetry（LSV）. The increased chain length of the surfactants led to an increased adsorption mass and an increased adsorption rate, thereby contributing to greater electrodeposition suppressive effects for longer chain analogs. Addition of H2SO4 into the aqueous surfactant systems and the consequent salting-out effect of SO42－ increased the cationic surfactants' adsorption mass. In the presence of SO42－, the adsorption mass increases because of increased hydrophobicity of the surfactants. It is noteworthy that further addition of HCl to the aqueous H2SO4 solution decreased the adsorption mass because Cl－ salting-in effects increased the hydrophilicity of the surfactants. The electrodeposition-suppressive effect was confirmed by LSV measurements as greater for the H2SO4 system than for the H2SO4＋HCl system. We therefore conclude that the greater adsorption mass induces the electrodeposition suppressive effect to a greater degree in cationic surfactant systems under acidic conditions.