Formation studies of TiC from carbon coated TiO2

This paper deals with the formation of titanium carbide from carbon coated titanium dioxide precursors. This study makes use of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and both scanning and transmission electron microscopy (SEM and TEM). DSC curves of both coated and mixed 33.2 wt % carbon containing titania demonstrates the superiority of the coated precursor by exhibiting both more reactions and reactions at lower temperatures than the mixed powder. Weight loss as powders were reacted in argon at varying temperatures was measured using TGA, while heat flow vs. temperature was measured by DSC. The weight loss allowed for calculation of the activation energy of TiC via the formation of various lower oxides of titanium. The activation energy was calculated as 731.6 +/- 24.2 kJ/mol. XRD was used to characterize the products resulting from the reaction of the carbon coated precursor at isotherms at each 100 degrees C interval from 1100 to 1500 degrees C, inclusive. These diffraction patterns support the hypothesis that the TiC formation proceeds through the formation of lower oxidation states of titanium. (C) 1999 Kluwer Academic Publishers.