Study on the Corrosion Behavior of LA141 Mg-Li Alloy in Different Cl− Environments

Salt spray tests with 0.1 wt% NaCl and 1 wt% NaCl solutions were used to investigate the corrosion behavior of LA141 Mg-Li alloy in different Cl− environments. The study used corrosion weight loss analysis, macro/micromorphological analysis, x-ray diffraction, and electrochemical tests. The results showed that in the 0.1 wt% NaCl salt spray environment, the corrosion weight loss rate of the alloy continuously decreased, whereas in the 1 wt% NaCl environment, it initially decreased and then increased. The corrosion products on the LA141 alloy surface were mainly composed of Mg(OH)2 and Li2CO3, along with minor amounts of MgCO3, LiOH, and Al2O3. Among these, the Li2CO3 in the corrosion product layer was stable and exhibited good corrosion resistance, contributing to the mitigation of substrate corrosion in low Cl− environments. However, when the Cl− concentration was high, this layer provided almost no protection to the substrate. In addition to Li2CO3, this study suggests that a small amount of Al2O3 also played a protective role at low Cl− concentrations. Nevertheless, when the concentration became excessively high, Al2O3 was destroyed, and Li2CO3 no longer provided significant protection.