Effect of the amounts of silicon on the in situ synthesis of Ti3SiC2 based composites made from TiC/Si powder mixtures

This paper describes how variations in silicon content and heat treatment influence the phase composition of TiC/Si powder mixtures during heat treatment. The sintering procedure is investigated with respect to the phases produced with a particular emphasis on maximisation of the Ti3SiC2 content. The heat treated products have been analysed using scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry. In the heat treated products Ti3SiC2 and TiC are the dominant phases and SiC and TiSi2 are found in smaller (0–30 vol.%) amounts. The composition was found to depend on both Si content and heat treatment temperature and time. The silicon content can be optimised with respect to maximum Ti3SiC2 production, but its value changes with different temperature programs. The highest amount (56 vol.%) of Ti3SiC2 is achieved by heat treating powder mixtures of initial composition 3TiC/2.2Si at 1350° for 1 h. Heat treatment at lower temperatures (1250–1300 °C) results in an incomplete reaction and production of TiSi2.