MICROSCOPIC AND ELECTROCHEMICAL CHARACTERIZATION OF ALUMINA CERAMIC FILMS DEVELOPED ONTO 316L STAINLESS STEEL BY MICRO-ARC OXIDATION IN PLASMA ELECTROLYSIS

The objective of this paper was to prepare and characterize alumina coatings developed on AISI 316L stainless steel by aluminizing treatment using micro-arc plasma oxidation in an aqueous solution containing 0.1 M NaAlO2 and 0.05 M NaOH. The obtained films were characterized by SEM microscopy and EDS analysis as well as by Tafel polarization curves and electrochemical impedance spectroscopy. Comparative results for steel samples subjected previously to two different surface pre-treatments (oxidation either by cyclic voltammetry in 0.1 M NaOH or in an autoclave with deionised water) were discussed.