Synthesis and some properties of Ti 3 SiC 2 by hot pressing of titanium,silicon,and carbon powders Part 1 – Effect of starting composition on formation of Ti 3 SiC 2 and observation of Ti 3 SiC 2 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.