SINTERING BEHAVIOR OF TIC REINFORCED SIC COMPOSITES DOPED WITH TI ANDC

SiC-TiC composites with different C/Ti ratio were hot-pressed at 2050 degrees C for 1h under vacuum. The ratio of C/Ti was controlled by the addition of Ti or C. Density of the sintered bodies decreased with in creasing C content. The SiC-TiC composite with a low C/Ti ratio, i.e., doped with 2 mass%Ti, could be densified up to 98% of the theoretical value. On the other hand, relative density of the specimens with high er C/Ti ratio reached only about 80%. Density of the monolithic SiC do ped with 2 mass%Ti was measured to be 73%. The presence of free Si and Ti3SiC2 phases was confirmed by XRD for the composites with lower C/T i ratio. Diffraction intensity of these peaks decreased with increasin g C content, and finally disappeared. Plastic deformation of TiC and f ormation of Si and Ti3SiC2 phases are believed to be the main factors to control the sintering behavior of SiC-TiC composite containing C de ficiency.