Abstract
The dyestuff adsorption of anodic oxide coating depended upon the conditions of anodizing and dyeing. The effects of the coating from mixed bath of sulfuric, oxalic, and citric acids on dyestuff adsorption were investigated by experiments under various conditons.
The following results were obtained:
(1) The coating was more porous and adsorption capacity of dyestuffs was more improved when the temperature and concentration of the bath were higher.
(2) In general, the adsorption capacity was higher with the increase of anodizing time, but it was remarkably lowered when the current density was higher.
(3) The adsorbed amount of dyestuffs was increased when their concentration and temperature wece higher, but it tended to be decreased when they were too high. Adjustment of pH had a significant effect, which gave the best result at a value of approximate to 4.
(4) It was observed that the real surface area of the film of 20μ in thickness was 195-368 times as large as its apparent surface area. The amount of dyestuffs adsorbed on the real surface was smaller than 0.091mg/dm2.
