Oxidation resistance of B2 rare earth-magnesium intermetallic compounds

The oxidation behaviors of YMg and CeMg were rneasured in flowing air using the thermal gravimetric analysis technique. Negligible oxidation is observed at room temperature in both compounds. At elevated temperatures, the rare earth metals oxidize preferentially, while the underlying materials transform into Mg-rich intermetallics before the Mg oxidizes to MgO. The oxidation resistance of YMg is several orders of magnitude greater than that of CeMg. The oxidation of YMg follows parabolic kinetics with an activation energy of 104 kJ/mol while that of CeMg obeys a linear law with an activation energy of 136 kJ/mol. (C) 2007 Elsevier B.V. All rights reserved.