Evaluation of anodized aluminum surface obtained from a sulfanic acid bathusing electrochemical impedance spectroscopy

Aluminum was anodized in a sulfamic acid bath, then sealed, using different sealing solutions, such as boiling deionized water (BW), triethanolanine ( TEA) and dichromate (D). Impedance data were obtained for both sealed and u nsealed anodized specimens in 3 % NaCl solution for various exposure times and a constant sealing time of 15 min. Data obtained have been analyzed and explained with the help of an equivalent circuit. The sealing using TEA wa s found best when compared to BW and D.