Mechanical processing and self-sustaining high-temperature synthesis of TiC powders

We report on the reactive behaviour of Ti-C powder system under mechanical work by milling. A gas-less combustion range was found under constant milling intensity extending from Ti73C27 to Ti30C70. By increasing the impact energy the ignition time decreases exponentially revealing the existence of a threshold energy below which the spontaneous spreading out of the reaction cannot take place. Mechanical pre-treatments were shown to have a large influence on conventional SHS experiments as far as the combustion temperature and propagation velocity of the reaction front are concerned. However, the apparent activation energy for the overall combustion process was found independent on the degree of mechanical activation of the reactants. (C) 2003 Elsevier B.V. All rights reserved.