Characterisation by EIS of ternary Mg alloys synthesised by mechanical alloying

• Published in: Electrochimica acta 2006-01, Vol.51 (8), p.1752-1760
• Main Authors: Brett, Christopher M.A., Dias, Lidia, Trindade, Bruno, Fischer, Robert, Mies, Sascha
• Format: Article
• Language: English
• Subjects: Applied sciences; Corrosion; Corrosion mechanisms; Electrochemical impedance; Exact sciences and technology; Magnesium alloys; Mechanical alloying; Metals. Metallurgy
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2005.02.124

Electrochemical impedance spectroscopy has been used to study the electrochemical behaviour of ternary Mg 60Ti 10Si 30 and Mg 88Ti 5Si 7 alloy samples fabricated by mechanical alloying of the elemental powders in an argon atmosphere. The influence of different milling times up to 25 h and heat treatment on the electrochemical behaviour of the samples, after compacting under pressure into disks, has been investigated in 0.1 M Na 2SO 4 and 0.01 M NaCl electrolyte solutions. Complementary measurements of open circuit potential, polarisation curves, and surface and microstructural analysis have been carried out. The experimental results revealed that corrosion is greater for Mg 88Ti 5Si 7 which contains free magnesium; however, in sulphate solution a protective oxide layer formed can reduce the corrosion rate. In Mg 60Ti 10Si 30, heat treatment increases corrosion, which is explained through a greater tendency for pitting corrosion. Comparison is made between the electrochemical impedance data and the nanophase structure as well as with the electrochemical behaviour of other magnesium alloys.