Enhanced corrosion resistance of magnesium alloy AM60 by cerium(III) in chloride solution

Cerium(III) was utilised to enhance the corrosion resistance of AM60 in NaCl solution. Ce3+ can suppress corrosion deterioration up to 1.0 mM. Beyond that level corrosion rate increases till a steady value. Surface film resistance increases with time evolution until 24 h, then decreases and stabilizes. The converted film after 240 h immersion exhibits self-healing and thickening when re-exposed to plain chloride solution. SEM and EDX confirmed that when Ce is present as additive in solution, more compact coating is formed better than its presence as a post coating on the alloy surface before being immersed in the corrosive environment.

► Corrosion rate of AM60 in Cl− solution decreases with increasing [Ce3+] up to 1 mM.
► Beyond that level the corrosion rate increases and then stabilizes.
► The spontaneously formed film characterises by increasing resistance with time.
► The converted film after 10 d immersion exhibits self-healing in plain Cl− solution.
► Ce(III) should be present in the corrodent to form a more compact surface coating.