A Study on the Corrosion Behavior in Sea Water of Welds Aluminum Alloy by Shielded Metal Arc Welding, Friction Stir Welding and Gas Tungsten Arc Welding

Three types of welds aluminum alloy 6061 were prepared using shielded metal arc welding (SMAW), friction stir welding (FSW) and gas tungsten arc welding (GTAW). In addition for the first time borax powder was used with GTAW in weld region to increase the corrosion resistance of aluminum alloys. The corrosion performances of those welds were evaluated in sea water by polarization and impedance techniques. The results of polarization studies and electrochemical impedance spectrometry revealed that borax powders can be used with GTAW technique to increase the corrosion resistance of aluminum alloys. The corrosion potential was lowest for GTAWB (borax powder doped), followed by FSW, GTAW, base metal (BM) and then SMAW as determined using polarization techniques. The rate of corrosion of FSW was found lower compared to other welds. The electrochemical impedance spectrometry (EIS) carried out at a higher frequency exhibited a semicircular loop for friction stir welds, indicating that its corrosion resistance was better than that of the other alloys studied. At medium frequency, the Warburg resistance observed for gas tungsten arc.