Ti3SiC2 synthesis from TiC and Si powders

Abstract: The aim of this work was to produce Ti3SiC2 from TiC and Si powders and to investigate process parameters with respect to optimised Ti3SiC2 yield. The reaction pathway of Ti3SiC2 formation and the thermochemical degradation reactions were examined. Various material characterization and analysis methods have been applied, including x-ray diffractometry, dilatometry, calorimetry, scanning electron microscopy, energy dispersive spectroscopy and mass spectroscopy. Through the work performed it has been found that Ti3SiC2 may be produced in relatively large quantities (96.8 vol%) from TiC and Si powders. Short holding times (0-3 hours) and relatively high temperatures (1350-1400°C) produce the largest amounts of Ti3SiC2 when pressureless sintering is applied.The effect of varying the silicon contents on yield was investigated; excess silicon may be beneficial for the Ti3SiC2 yield if combined with appropriate heat treatments. TiSi2 is found to play a key role in the formation of Ti3SiC2 from TiC and Si powders. TiSi2 is present in samples heat treated at relatively low temperatures with short holding times. It is consumed in the formation of Ti3SiC2. Decomposition of Ti3SiC2 may occur at relatively low temperatures (1300°C) when there is oxygen present in the furnace atmosphere. The effect becomes more significant with long holding times (> 5 hours) and is also significant at very high temperatures (1500°C). When the partial pressure of oxygen is limited, no decomposition has been observed below 1450°C. At these temperatures, the presence of carbon in the furnace atmosphere induced no detrimental effect on the thermochemical stability of Ti3SiC2.