Electrochemical characteristics of Al-Mg and Al-Mg-Si alloy in sea water

Among Al alloys, particularly 5000 series Al-Mg and 6000 series Al-Mg-Si often used as marine materials have excellent corrosion resistance, low melting point, and thereby showing recycling availability when compared to other metals. Variety experiments were conducted to select the most suitable material for marine environments. All electrochemical experiments were conducted in natural seawater. The corrosion test was performed in many methods such as anodic/cathodic polarization and Tafel analysis using multi-channel potentio/galvanostat WMPG-1000. As results, anodic and cathodic polarization behaviors indicate the characteristics of passive state and concentration polarization by reduction reaction in dissolved oxygen, which shows excellent electrochemical behaviors. Tafel analysis results show no significant difference but 5052-O alloy of various alloy materials indicates the lowest corrosion current density. Therefore, 5052-O Al alloy presents most anti-corrosion material in marine environment.