Journal of Materials Research and Technology Journal of Materials Research and Technology
J Mater Res Technol 2017;6:40-9 DOI: 10.1016/j.jmrt.2016.04.003
Original Article
Electrochemical corrosion study of Mg–Al–Zn–Mn alloy in aqueous ethylene glycol containing chloride ions
Harish Medhashree, Adka Nityananda Shetty,
Department of Chemistry, National Institute of Technology Karnataka, Mangalore, India
Received 24 July 2015, Accepted 12 April 2016
Abstract

Nowadays most of the automobiles use magnesium alloys in the components of the engine coolant systems. These engine coolants used are mainly composed of aqueous ethylene glycol along with some inhibitors. Generally the engine coolants are contaminated by environmental anions like chlorides, which would enhance the rate of corrosion of the alloys used in the coolant system. In the present study, the corrosion behavior of Mg–Al–Zn–Mn alloy in 30% (v/v) aqueous ethylene glycol containing chloride anions at neutral pH was investigated. Electrochemical techniques, such as potentiodynamic polarization method, cyclic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of Mg–Al–Zn–Mn alloy. The surface morphology, microstructure and surface composition of the alloy were studied by using the scanning electron microscopy (SEM), optical microscopy and energy dispersion X-ray (EDX) analysis, respectively. Electrochemical investigations show that the rate of corrosion increases with the increase in chloride ion concentration and also with the increase in medium temperature.

Keywords
Mg–Al–Zn–Mn alloy, Ethylene glycol, Cyclic polarization, EIS, EDX, SEM
J Mater Res Technol 2017;6:40-9 DOI: 10.1016/j.jmrt.2016.04.003