EFFECT OF PRECURSORS ON THE COMBUSTION SYNTHESIS OF TIC-AL2O3 COMPOSITE

In the combustion synthesis of TiC-Al2O3 composites from TiO2, Al, and C, different types of precursors, i.e., anatase and rutile TiO2, and graphite and carbon black were used. The measurements of combustion wave velocity showed that the reactivity was higher with graphite as a carbon source and anatase as a TiO2 source. This was also confirmed by analyzing the degree of conversion of reactants to products. For the precursors investigated, the wave propagation of the 3TiO2-4Al-3C system diluted by Al2O3 showed that the limit of wave propagation was more dependent on carbon source than on TiO2. The wave front of all the samples proceeded in unstable combustion mode. Temperature profiles in the reaction zone suggested that the heat-affected zone was broader in the case of graphite carbon source than carbon black. The microstructures and chemical composition of the products were also studied.