Corrosion and impedance studies on magnesium alloy in oxalate solution

Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br⁻, Cl⁻ or SiO₃²⁻) on the electrochemical behavior of magnesium alloy in 0.1 M Na₂C₂O₄ solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na₂C₂O₄). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br⁻ or Cl⁻, the corrosion rate is higher than the blank.