Effect of CaCl 2 and NaHCO 3 in Physiological Saline Solution on the Corrosion Behavior of an As-Extruded Mg–Zn–Y–Nd alloy

In this study, the corrosion behaviors of an as-extruded Mg–4%Zn–2%Y–1.8%Nd (in wt.%) alloy in different physiological saline solutions were investigated and compared. The results indicated that the alloy in the 9 g/L NaCl had the higher corrosion resistance than that containing with CaCl2 and NaHCO3. Moreover, it demonstrated that the corrosion behaviors of the alloy in two types of solutions were all dependent on the pre-immersion time. In the 9 g/L NaCl solution, the corrosion current densities of the alloy decreased firstly with the pre-immersion time being < 4 h and then increased with the pre-immersion time prolonging from 4 to 48 h. However, in the 9 g/L NaCl solution containing with CaCl2 and NaHCO3, the corrosion current density of the alloy exhibited the adverse trend with the prolonging the pre-immersion time. Failure analysis demonstrated that the changes of corrosion resistance in two solutions were mainly dominated by the constituents formed in surface films.