Corrosion and electrochemical behaviors of As-cast Mg-8Y and Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloys in nacl aqueous solution

The corrosion mechanisms of as-cast Mg-8Y and Mg-5Y-7Gd-1Nd-0.5Zr Mg alloys in 5% NaCl aqueous solution were investigated by electrochemical testing and SEM observation. The electrochemical results indicated that the corrosion resistance of Mg-8Y and Mg-5Y-7Gd-1Nd-0.5Zr alloys in 5% NaCl aqueous solution gradually deteriorated with increasing of immersion time expect for 2h and 24h immersion. The Cl- anion led to the initiation and development of the corrosion pits. The cathodic reaction was driven by hydrogen evolution reaction. The presence of filiform corrosion also proved a resistant oxide film naturally formed on the surface of Mg-8Y and Mg-5Y-7Gd-1Nd-0.5Zr alloys. The corrosion resistance of Mg-5Y-7Gd-1Nd-0.5Zr was better than Mg-8Y.