The Corrosion Behaviours of AZ61 Magnesium Alloy with the Ca Addition

Abstract

the corrosion behaviors of AZ61 magnesium alloy with the Ca addition have been studied in this paper. These alloys were prepared in an induction melting furnace with an Al 2 O 3 crucible under a mixed atmosphere of CO 2 and SF 6. The corrosion tests were completed using immersing in 0.5% and 3.5% NaCl solution for 4 hours at room temperature with no stirring. The phase analysis was performed by XRD. Olympus optical was used to characterize the microstructure and phases of magnesium alloys. Scanning electron microscopy was used to exhibits the morphologies of corroded surfaces of magnesium alloys after removal of the corrosion products. The results exhibited that with the addition of alloy element Ca, the microstructure of AZ61 magnesium alloy was remarkably refined, and the spotted, high-melting point phase Al-Ca intermetallic compounds can be found. With the addition of different content Ca, the corrosion behavior of AZ61 alloy decreases firstly and then increases sharply. When the content of Ca is 1%, AZ61 magnesium alloy shows the lowest corrosion rate. And the corrosion rate of AZ61-1% Ca alloy is 2.19 and 2.87 mm/a at 0.5% and 3.5% NaCl solution respectively.

Corrosion and Protection of Magnesium Alloys: Recent Advances and Future Perspectives

“…The corrosion behavior of an AZ Mg alloy containing Ca was studied and discussed. It was discovered that as the concentration increased, the corrosion rate of the AZ61 alloy dropped first and then creased quickly; the lowest corrosion rate occurred when the Ca content was 1% [56]. T corrosion rate of AZ31-0.5Ca in AZ31-xCa magnesium alloy was the lowest, owing to formation of corrosion products of Al2O3 and CaCO3 films (Figure 6) [57].…”

“…The element Ca is commonly utilized in AZ series Mg alloys and has a positive effect on refining the microstructure of the alloy [56,57]. The corrosion behavior of an AZ61 Mg alloy containing Ca was studied and discussed.…”