Effect of an external electric field on the combustion synthesis process of TiO₂-C-Al system

Taking 3TiO₂+3C+(4+x)Al as a reaction system, a dense TiC-Al₂O₃-Al composite was directly prepared. The effect of electric-field on the combustion synthesis process of the system was systematically investigated. The results show that the imposition of an external electric field can improve the adiabatic temperature of the reactive system and induce its self-sustaining combustion synthesis process. The electric field also can change the combustion modes of the system. With an increase of the field strength, both the combustion temperature and the self-propagating wave velocity are increased obviously, while the grain size of the in-situ synthesized TiC and Al₂O₃ particles is decreased significantly. Under the conditions of the Al residual x being 14mol in the system and the electric field strength E being 25V/cm, a dense TiC-Al₂O₃-Al composite with a relative density of 92.5% can be successfully fabricated, in which TiC and Al₂O₃ particles have a fine size of 0.2~1.0mm, and distribute uniformly in metal Al.