Materials and Corrosion. 2019;1–9. www.matcorr.com © 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim | 1 Received: 15 January 2019 | Accepted: 25 April 2019 DOI: 10.1002/maco.201910810 ARTICLE The effect of temperature on corrosion behavior of AA5083 in brackish water and seawater Lea Lokas 1 | Vesna Alar 2 1 Competence Center AluTech, Sibenik, Croatia 2 Department of Welded Structures, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Zagreb, Croatia Correspondence Lea Lokas, Competence Center AluTech, Velimira Skorpika 6, 22000 Sibenik, Croatia. Email: lea.lokas@alutech.hr Funding information Competence Center AluTech Al‐alloy, AA5083, as a lightweight structural material with favorable mechan- ical properties and, compared with other lightweight materials, good corrosion resistance has an increased usage in the marine environment. It is well known that all Al‐alloys, including AA5083, in the presence of chloride ions are more prone to corrosion. Determination of corrosion behavior of AA5083 in seawater and brackish water has been investigated and compared at 18, 25, and at 30°C. 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 the following electrochemical methods: open circuit potential measurement, electrochemical impedance spectroscopy, linear polarization resistance, potentiodynamic polarization, and cyclic polarization. After poten- tiodynamic polarization measurement, each alloy was examined using a metallographic microscope to clarify corrosion morphology. Obtained results have shown that an increase in temperature leads to an increase in corrosion activity of AA5083 in both electrolytes, while microscopic examination reveals that the dominant type of corrosion is pitting. KEYWORDS aluminum alloy, brackish water, electrochemical techniques, pitting corrosion, seawater 1 | INTRODUCTION The increasing demand in the marine industry to lower the fuel consumption and to have a higher speed of the vessel has emphasized the importance of lightweight structural materials, like aluminum alloys, that possess a good combination of material property requirement. Although AA5083 has good corrosion resistance due to the presence of a protective oxide layer on the surface, while exposed to brackish water and seawater, passive film breakdown happens. Thus, in an aqueous envir- onment with a high concentration of Cl - ions, there is a considerable corrosion occurrence. [1] The breakdown mechanism of formed film and the appearance of pitting corrosion was reported and explained by Sherif. [2] Further, aluminum alloys resistance on pitting corro- sion (and other types of localized corrosion) in saline environments highly depends on defects in the oxide layer. Namely, the oxide layer can be easily destroyed by scratching which can lead either to pitting corrosion or, in a better scenario, to repassivation. Furthermore, present precipitates on the surface, which are formed by the alloying elements to improve properties, can create weak points in the oxide layer. Acosta et al [3] investigate the effect of present precipitates on oxide film breakdown and pitting formation and propagation after 6 months exposure to seawater. As a result, many different microcracks have been found, [4] as well as change from intergranular to pitting corrosion with increasing ex- posure time. According to Gupta et al, [5] certain potential pits can be repassivated and that phenomenon is known