Flammability Limits, Dilution Limit, and Effect of Particle Size on Burning Velocity in Combustion Synthesis of TiC.

Abstract

Flame-front propagation in a densified condensed medium of Ti and C is studied experimentally. Effects of mixture ratio, diameters of particles, relative density, and degree of dilution on burning velocity are investigated. Burning velocity has been defined as the flame-front velocity normal to its surface through the adjacent unburned condensed medium. Results shows that there exist flammability limits, over which flame-front propagation occurs, and outside of which the flame cannot be self-sustained. The diameter of carbon particles is found to exert great influence on the burning velocity, while that of Ti particles has no remarkable effects when particle sizes are smaller than the thickness of the combustion region. Dilution with the combustion product is also shown to be effective in controlling the burning velocity while there exists a dilution limit beyond which the flame front ceases to propagate.