An Investigation on the Mechanism of TiC+AI2O3 Combustion Synthesis via Mechanical Activation of Double Phases in TiQ2-AS-C System

摘要

The starting reaction in the combustion synthesis process in TiC>2-Al-C system leading to TiC+A^C^ composite was evaluated using a combination of Differential Thermal Analysis (DTA), X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM). Double phases in 3TiO2-4A1-3C system were milled separately and then the third phase was added according to the stoichiometric reaction for 3TiC+2Al2C>3 composite formation. The combustion synthesis temperature was observed to decrease from 962 °C to 649 °C after mechanical activation of TiC^/Al mixture for 16 hr On the contrary, the mechanical activation of Al/C and TiCVC mixtures for 16 hr made the reaction temperature increase to 995 °C and 1024 °C, respectively, TEM and XRD patterns of as-milled powders showed that the reaction temperature changes could be due to increased TiC>2 and Al interface area In addition, DTA experiments showed that for the sample in which TiC>2 and Al were mechanically activated the reaction occurred at the temperature even lower than the aluminum melting point.