Study on Corrosion Behavior of 5083-H116 Aluminum Alloy in 0.1%Cl^- Aqueous Solution

The corrosion behavior of 5083-H116 aluminum alloy in 0.1%Cl^- aqueous solution was investigated by total immersion corrosion test, alternate immersion corrosion test, metallography(OM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observation. The results show that the 5083-H116 aluminum alloy precipitates nano-level Al₆Mn dispersed phase and micron-level Al₆(Mn, Fe) impurity phase, and no Al₃Mg₂ and Mg₂Si phases are precipitated at the grain boundary, which are easy to cause intergranular corrosion of aluminum alloy. In total immersion environment, the 5083-H116 aluminum alloy has local corrosion mainly by pitting corrosion, and the corrosion product is mainly Al(OH)₃. In the alternate immersion environment, 5083-H116 aluminum alloy also occurs local corrosion, but relatively mild, corrosion products include CaCO₃ and Al(OH)₃. The corrosion rate per unit area of 5083-H116 aluminum alloy in total immersion environment shows a trend of first increase and then levels off with the extension of immersing time. The pitting density increases gradually and the maximum pitting corrosion rate reaches 1.66 mm/year. The corrosion rate of alternate immersion environment is lower, and it is safer than that of total immersion environment area