Synthesis of molybdenum silicides by the self-propagating combustion method

Abstract

The synthesis of the silicides of molybdenum (Mo3Si, Mo5Si3, and MoSi2) by the self-propagating combustion method is investigated. Only the reactants corresponding to the last phase can be reacted in a self-sustaining mode without preheating. The product of such a reaction is single-phase MoSi2. Although reactant mixtures corresponding to the other two silicides can react in a self-sustaining mode with prior heating, the products of combustion were multi-phase. The dependence of the combustion temperature and velocity on the stoichiometry of the silicide was determined. The activation energy for the combustion synthesis of MoSi2 determined in this investigation, 139.4 kJ mol−1, is considerably lower than activation energies reported for the diffusion of silicon in molybdenum or in MoSi2.