Influence of chloride ion concentration on initial corrosion of AZ63 magnesium alloy
(1. Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11020 Belgrade, Serbia;
2. Serbian Academy of Science and Arts, Institute of Technical Science, Knez Mihailova 35, 11000 Belgrade, Serbia)
2. Serbian Academy of Science and Arts, Institute of Technical Science, Knez Mihailova 35, 11000 Belgrade, Serbia)
Abstract: The initial corrosion behavior of AZ63 magnesium alloy was investigated in 1, 3, 5 and 7 wt.% NaCl solutions by means of corrosion potential, linear polarization, electrochemical impedance spectroscopy, and polarization measurements, during exposure in the corrosion media. Results show that the increase in chloride concentration provokes an increase in the corrosion rate. Based on the obtained kinetics parameters the mechanisms of anodic dissolution and hydrogen evolution reactions were discussed, and kinetic models were proposed. It is concluded that anodic dissolution proceeds under Temkin conditions and hydrogen evolution reaction depends on the surface coverage of Mg(OH)2 species.
Key words: chloride; corrosion potential; linear polarization; reaction order; kinetics