Synthesis and some properties of Ti3SiC2 by hot pressing of titanium, silicon, and carbon powders Part 1 – Effect of starting composition on formation of Ti3SiC2 and observation of Ti3SiC2 crystal morphology

Abstract

Dense Ti3SiC2 bulk ceramic was synthesised by hot pressing of elemental titanium, silicon, and carbon powders. The effects of starting composition of the powders on the synthesis of pure Ti3SiC2 were examined. Phase identification was carried out by X-ray diffraction. Silicon content in the starting composition played an important role in formation of the final constituent phases in the composite. It was difficult to obtain the pure phase Ti3SiC2 because other thermodynamically stable reaction products such as TiC, TiSi2, or Ti5Si3 were always present together with Ti3SiC2. The microstructure of samples was examined using scanning electron microscopy and transmission electron microscopy. Observations showed that the Ti3SiC2 matrix was composed of elongated, platelike, and equiaxial grains. It is suggested that the hexagonal crystal Ti3SiC2 exhibits anisotropic grain growth behaviour. The relative growth rates on different planes, therefore, endow Ti3SiC2 with several morphologies.