The corrosion behavior of AZ31 alloy in chloride and sulfate media A comparative study through electrochemical investigations

Abstract

The magnesium alloys are considered to be the best structural materials, because of their advantageous weight to strength ratio. But, the limitation in their real field applications lies on the fact that magnesium alloys are highly susceptible for corrosion. The corrosion behaviour of AZ31 alloy was investigated by electrochemical methods in sodium chloride and sodium sulphate of different concentrations at different temperatures. The corrosion rate was monitored by potentiodynamic polarization technique and electrochemical impedance spectroscopy method. The surface morphology and surface composition of the freshly polished surface of the alloy was compared with that of the corroded surface by recording their SEM images and EDS, respectively. The results showed that the corrosion rate of AZ31 alloy increased with the increase in the temperature of the medium and also with the increase in the salt concentration of the medium. The activation parameters for the corrosion process were calculated and interpreted. 2019