The effect of mechanical activation on highly exothermic powder mixtures

The formation of MoSi2 by ball milling a mixture of Mo and Si powders can t ake place according to a self-propagating reaction, The mechanical activati on that leads to the initiation of this process, is investigated by structu ral and thermal analysis of samples milled for periods shorter than the ign ition time. It is shown that the ignition temperature does not change subst antially upon milling. The main change is an increase of the interface area and, consequently, transformation of a larger fraction of the reactants wh en solid state reaction is initiated by heating. (C) 2001 Elsevier Science B.V. All rights reserved.