Electrochemical investigations on the corrosion behaviour of magnesium alloy ZE41 in a combined medium of chloride and sulphate

Abstract

The magnesium alloy ZE41 encompasses a wide spectrum of applications as a structural material. An extremely high susceptibility to corrosion limits widespread utility of ZE41. In the present study it has been attempted to understand the corrosion behaviour of ZE41 alloy employing electrochemical techniques like Tafel extrapolation and electrochemical impedance spectroscopy (EIS) in aqueous salt solutions containing mixture of sodium chloride and sodium sulphate over a varying range of electrolyte concentrations and solution temperatures. The morphology of the metal surface has been established by means of scanning electron microscopy (SEM). The results indicate that the rate of corrosion of ZE41 alloy increases with the increase in temperature and ionic concentration of the medium. The results of corrosion rates at varying temperatures have been utilized in the calculation of activation parameters such as activation energy, enthalpy of activation and entropy of activation for the corrosion process. © 2013 National Engineering Research Center for Magnesium Alloys of China, Chongqing University.