An investigation was made of oxidation behavior at 700 to 1185C. Results obtained by thermogravimetric analysis showed that the initial oxidation exhibited parabolic kinetics at 800 to 945C. The oxidation process had temperature dependence, with an activation energy of 195±15kJ/mol in air and in pure oxygen atmospheres. Two possible reactions, evaporation of B2O3 species (at ≥945C) or oxidation of surface LaB6 (≤800C), influenced the oxidation mechanism, resulting in the mass loss deviating from parabolic behavior.

Oxidation Kinetics of LaB6 in Oxygen Rich Conditions. Wen, C.H., Wu, T.M., Wei, W.C.J.: Journal of the European Ceramic Society, 2004, 24[10-11], 3235-43