Behavior of CaO and Calcium in pure Magnesium

摘要

Mg alloys exhibit a number of good properties such as low density, good castability and high specific strength. However, molten Mg and Mg alloys are ignited without the melt protective gases during melting and casting process due to their high reactivity. The purpose of this study is to investigate effects of Ca and CaO on pure Mg through microstructure observation, ignition test and phase analysis. With increasing Ca and CaO contents, the ignition resistance of Ca or CaO added pure Mg is increased and the grains are refined . As results of XRD and EDS, CaO is reduced to Ca in CaO added pure Mg. Mg_2Ca phase is formed even in 0.1 wt. % CaO added pure Mg by reduction mechanism, while Mg_2Ca phase is formed over 1.35 wt. % Ca added pure Mg.