Effects of Doping Si on the Preparation of Ternary Titanium Aluminum Carbide Powder by Pressureless Sintering

Ternary titanium aluminum carbide powder was prepared by pressureless sintering at different temperature using elemental powder mixture of Ti, Al, and active carbon whose molar ratios was 3Ti/1.1Al/1.8C and effects of doping Si were discussed from 3.0Ti/1.0Al/0.1Si/1.8C and 3.0Ti/0.9Al/0.2S/1.8C. X-ray diffractions (XRD) patterns were used to detect the phase composition and scanning electron microscope (SEM) patterns were observed to investigate the microstructure of samples respectively. Results showed that Ti2AlC and Ti3AlC2which had obvious layered structure were synthesized by pressureless sintering of 3Ti/1.1Al/1.8C at 1300°C-1500°C. However, the samples doping Si were made of Ti2AlC, Ti3AlC2and Ti3SiC2. When the amount of Si-doped increased and Al/Si decreased, the amount of Ti3AlC2and Ti3SiC2went up with Ti2AlC going down. Interestingly, the character of layered structure became unconspicuous at same temperature. Moreover, the mechanism that doping Si was not helpful to form Ti2AlC but Ti3AlC2was explained.