Early high temperature oxidation behaviors of Mg–10Gd–3Y alloys

Abstract

In the present study, the isothermal early oxidation behaviors of Mg–10Gd–3Y alloys were studied over the temperature range of 723–873 K in pure O 2 up to 90 min. In general, the oxidation kinetics of the Mg–10Gd–3Y alloys obeyed a parabolic rate law, and the higher the oxidation temperature was, the greater the oxidation rate was. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to analyse the formed oxide film. The results indicated that an oxide film with a duplex structure had formed, which was composed of Gd 2O 3, Y 2O 3 and little MgO. The oxide scale morphologies were observed by scanning electron microscopy (FEI, SEM), which showed a dense and compact film. In contrast to pure Mg, the improved oxidation resistance of the Mg–10Gd–3Y alloys can be due to the formed dense oxide film. Finally, the corresponding oxidation mechanism, which represented a complex process during the isothermal oxidation, was also discussed.