This paper describes how the preparation and heat treatment of TiC/Sipowders influences the phase reactions during firing. The powders are prepared by milling andsome effects of powder preparation are discussed. A solid state displacement reactionaccording to: 3TiC + 2Si → Ti3SiC2 + SiC is a priori expected to take place during heattreatment. The firing procedure is investigated with respect to the effect of heat treatment timeand temperature on the phases produced, especially Ti3SiC2. Samples were heat treated in agraphite lined furnace. Heat treated samples are analysed by x-ray diffraction, scanningelectron microscope and energy dispersive spectroscopy. Ti3SiC2, TiC and SiC are dominant inthe final products. The highest amount of Ti3SiC2 is achieved for short holding times (2-4hours) at high temperatures (1350-1400ºC). Ti3SiC2 appears to decompose at elevatedtemperatures or extended times, through a Ti3SiC2 ® TiC + Si(g) type reaction. The activationenergy of Ti3SiC2 phase formation is determined to be 289 kJ/mol, using the Mehl-Avrami-Johnson model.