An electrochemical approach to the anodic oxidation of Al 2024 alloy in sulfuric acid containing inhibitors

In order to replace hexavalent chromium in anodising process, cerium IV and molybdate ions have been identified as corrosion inhibitors. This paper describes the effect of molybdate and cerium IV species added to sulfuric acid on anodic film formation on the 2024 aluminium alloy. Both voltammetric and chrono-potentiometric techniques have been used to investigate the electrochemical behaviour of the system and to determine the role of these compounds on film formation. The results obtained have indicated that oxide films growth has been promoted in the presence of cerium IV ions and has been hindered with molybdate ions.