On the oxidation behaviour of MoSi2

The oxidation behaviour of MoSi2 has been analyzed on the basis of thermody namics and kinetics. Thermodynamically speaking silica is in equilibrium wi th ally of the stable molybdenum silicides. At low temperatures, the limite d bulk diffusion in MoSi2 makes it impossible to sustain a sufficient suppl y of silicon for the formation of a continuous silica layer. This leads to the simultaneous-oxidation of silicon and molybdenum, forming a scale of mi xed oxides. The formation of molybdenum oxides leads to ruptures owing to t he significant volume change and accelerates the oxidation, leading to the pest phenomenon. (C) 2001 Elsevier Science Ltd. All rights reserved.