Reaction hot-pressed sub-micro Al2O3+TiC ceramic composite

Combustion reaction 3TiO2+3C+4Al⇒3TiC+2Al2O3 has been studied by X-ray diffractometer (XRD), differential scanning calorimeter (DSC) and differential thermal analysis (DTA). The exothermal combustion reaction was observed at a temperature of about 1000°C. Poor wetability between liquid Al and TiO2 (or graphite) solid particles results in an undesired, inhomogeneous microstructure through direct combustion hot-pressing. In the present work, the reaction 3TiO2+3C+4Al⇒3TiC+2Al2O3 has been modified into two separate steps: (1) room-temperature treatment: 3TiO2+3C+4Al⇒amorphousphase(notidentifiedyet)+Ti, (2) reaction hot-pressing: amorphousphase+Ti⇒3TiC+2Al2O3. A sudden shrinkage was also observed around 1000°C during reaction hot-pressing. Since no liquid phase appeared during reaction hot-pressing, a high-performance Al2O3+TiC ceramic composite with sub-micron grains and homogenous microstructure was manufactured.