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

• Published in: Corrosion science Vol. 56; pp. 86 - 95
• Main Authors: Heakal, F. El-Taib, Shehata, O.S., Tantawy, N.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2012; Elsevier
• Subjects: A. Magnesium; Alloying additive; Applied sciences; B. EIS; B. Polarisation; B. SEM; C. Neutral inhibition; Chloride resistance; Chlorides; Coating; Corrosion; Corrosion environments; Corrosion resistance; Deterioration; Evolution; Exact sciences and technology; Magnesium base alloys; Metals. Metallurgy; B. SEM; A. Magnesium; B. Polarisation; B. EIS; C. Neutral inhibition; Scanning electron microscopy; Lanthanide; Cerium; Corrosion resistance; Magnesium base alloys; Corrosion; Cerium chloride; Impedance
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2011.11.019

► Corrosion rate of AM60 in Cl − solution decreases with increasing [Ce 3+] 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. Cerium(III) was utilised to enhance the corrosion resistance of AM60 in NaCl solution. Ce 3+ 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.