KINETIC-ANALYSIS OF THE COMBUSTION SYNTHESIS OF MOLYBDENUM AND TITANIUM SILICIDES

The temperature profiles associated with the passage of self-propagating combustion waves during the synthesis of MoSi2 and Ti5Si3 were determined. From these profiles, kinetic analyses of the combustion synthesis process for these two silicides were made. The synthesis is associated with high heating rates: 1.3 x 10(4) and 4.9 x 10(4) K . s(-1) for MoSi2 and Ti5Si3, respectively. The width of the combustion zone was determined as 1.3 and 1.8 mm for the silicides of Mo and Ti, respectively. The degree of conversion, eta, and its spatial distribution and the conversion rate, partial derivative eta/partial derivative t, were determined. However, because of the inherent characteristics of wave propagation in MoSi2, only in the case of Ti5Si3 could the activation energy be calculated. An average value of 190 kJ . mol(-1) was determined for titanium silicide.