Protection of magnesium melt by hexafluoropropylene/air atmosphere

Abstract

Abstract The protection of hexafluoropropylene/air mixed gas for molten magnesium at temperatures from 670 °C to 800 °C has been investigated. The morphology and the composition of the protective film formed on the surface of the melt at 700 °C for holding time of 30 min and 60 min were investigated by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results showed that the protective effect of the mixed gas on molten magnesium increased with the increasing of hexafluoropropylene concentration, the prolongation of holding time and the decrease of temperature. The protective film on the surface of the melt was uniform and continuous, and mainly composed of MgF2 and small amount of MgO.