Effect of chloride ion concentration, spraying time and pH values on corrosion behavior of friction stir welded AZ61A magnesium alloy welds in salt fog environments

Abstract

The present research devoted to the investigation of the corrosion behavior of AZ61A FSW welds in accelerated conditions, including the influence of salt fog environmental parameters such as chloride ion concentration, pH, and duration of exposure. Significant numbers of tests were carried out that make possible to create the regression model (empirical equation) of influence of selected environmental parameters on corrosion rate. The corrosion products were analyzed by SEM and XRD analysis. This research demonstrates the effect of chloride ion concentrations, spraying time and pH values on corrosion rate, and it show the corrosion activity decelerates with the increasing pH value and spraying time respectively. It was found that the increase in chloride ion concentration accelerates the corrosion of AZ61A weldments. The corrosion morphology was predominantly influenced by the distribution of β-phase (e.g. Mg17Al12 intermetallic).