Influence of the Anodic Oxidation Treatment on the Corrosion Behaviour of Aluminium and Aluminium Alloys

Abstract

This paper deals with the effect of anodic oxidation treatment on the corrosion behaviour of 6061 aluminium alloy in natural sea water. Anodic oxidation treatment leads to the formation of an amorphous oxide layer on the top surface of 6061 aluminium alloy as shown by optical microscopy results. The corrosion behaviour was investigated in natural sea water, harvested from the Black Sea, Mangalia harbour. The study was done by in situ electrochemical methods such as: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PD) and cyclic voltammetry polarization (CV). The results show that the untreated 6061 aluminium alloy undergoes severe corrosion in natural sea water in comparison with anodized 6061 aluminium alloy. The results obtained by different electrochemical methods were in good agreement with each other and showed an improved corrosion resistance of the anodic oxide layer formed on aluminium alloy in natural sea water. The results were confirmed by optical microscopy.