材料期刊网

The EIS of the anodic dissolution process of pure aluminum in an alkaline solution was fitted using expression of Faradic admittance previously proposed by Cao([11-12]), based on which the mechanism of the process was proposed. The results show that the capacitive loop in low frequency region of EIS is caused by the reaction of Al(ss), and the inductive loop in middle frequency region is caused by the reaction of Al(OH)(ads). The time constants of Faradic admittance tau(1) and tau(2) mean the converting time of unit species Al(ss) and Al(OH)(ads) on unit bare surface site. Generally, tau(1) and tau(2) both decrease with the increase of the potential E. tau(1), > 0, tau(2) > 0, satisfy the conditions required by stability, and by Kramers-Kronig transforms as well. g(1) and g(2) relate to the variation of covering density of reactants Al(ss) and Al(OH) (ads). g(1) < 0 indicates that the aluminum surface tends to be passive when the potential increases.