The effect of temperature on corrosion behavior of AA5083 in brackish water and seawater

Al-alloy, AA5083, as lightweight structural material with favourable mechanical properties and, compared to other lightweight materials, good corrosion resistance has an increasing usage in marine environment. It is well known that all Al-alloys, including AA5083, in presence of chloride ions are more prone to corrosion. Determination of corrosion behaviour of AA5083 in seawater and brackish water has been investigated and compared at 18°C, 25°C and at 30°C. In order to obtain more accurate and realistic results, fresh seawater and brackish water were sampled as an electrolyte in Sibenik region. The investigation was carried out using following electrochemical methods: open circuit potential measurement, electrochemical impedance spectroscopy, linear polarization resistance, potentiodynamic polarization and cyclic polarization. After potentiodynamic polarization measurement, each alloy was exterminated using metallographic microscope in order to clarify corrosion morphology. Obtained results have shown that increase in temperature leads to an increase in corrosion activity of AA5083 in both electrolytes, while microscopic examination reveals that dominate type of corrosion is pitting.