N-HETEROCYCLIC ORGANIC-COMPOUNDS AS ADDITIVES FOR A-C ELECTROLYTIC COLORING OF ANODIZED ALUMINUM FROM NICKEL SULFATE-SOLUTIONS .2. MECHANISM OF THEIR ACTION

In this study, an attempt was made to investigate the mechanism of the action of piperidine-4-carboxylic acid in comparison with piperidine- 3-carboxylic acid during a-c electrolytic coloring of anodized aluminu m in nickel sulfate-boric acid solution, Electrochemical impedance spe ctroscopy (EIS) data were used, as well as some other electrochemical techniques, Conformations of the additives that influence action betwe en the opposite charges seem to play a significant role, They are corr elated with the ability of the additive to be adsorbed on the electrod e surface despite the alternating current, to interfere in the re-anod izing process, and in the nickel deposition rate and distribution.