Influence of triethanolamine additions on the sealing mechanism of anodised aluminium

Triethanolamine (TEA) solutions have previously been demonstrated to favour sealing of anodic films on aluminium. This work compares the sealing process in TEA and in de-ionised water using electrochemical impedance spectroscopy (EIS), standard tests for the study of the sealing quality and weight change measurements. It is demonstrated that the catalytic effect of the TEA is due not only to its pH, but also to its specific chemical structure. The data obtained are used to propose a sealing mechanism in this medium.