Abstract
Anodic oxide films formed on aluminum in sulfuric acid, have been electrolytically colored in a mixed aqueous solution of nickel sulfate and boric acid with sinusoidal alternating current. Deformed form of the current wave observed on a synchroscope, consisted of three components: non-Faradic current (iNF), anodic current (ia) and cathodic current (ic). These currents were measured separately. It was found that iNF was due to the current pass through the capacitive component of the barrier layer, whereas ia was due to the re-anodizing of the oxide film in the coloring bath, and observed only in the beginning of a. c. electrolytic coloring. Decrease of ic during a. c. electrolytic coloring seemed to be mainly due to the deposition of aluminum hydroxide in the pores of oxide films.
