Structure analysis of surface layer on passivated magnesium powders

The combustion-time of the passivated magnesium powders as desulfurizer was determined to be about 15.7 s, much higher than that of non-passivated magnesium powders. The surface layer of the passivated magnesium powders was studied by using SEM, XRD and AES. It is uniform and compact and no obvious holes or cracks have been found from the SEM micrographs. The result of XRD indicates that the surface layer mainly consists of CaO and MgO and probably a small quantity of SiO2. Based on the AES depth profile analysis, the surface layer of the passivated magnesium powders can be divided into three sublayers and the estimated depth of the layer is about 2.5 μm.