Synthesis of TiC and SiC/TiC nanocrystalline powders by gas-phase laser-induced reaction

In the development of advanced ceramic nanocomposites, the production of titanium-based nanopowders has assumed importance, especially since recent results showed that mechanical properties of SiC matrices could be significantly improved by the incorporation of TiC second phase and vice versa. Nanosized TiC and TiC/SiC powders were synthesized by CO2 laser-induced reactions. A TiCl4 and hydrocarbons mixture was irradiated for titanium carbide production; the addition of SiH4 gave rise to the composite powders. The results of the powder characterization, obtained mainly by X-ray photoelectron spectroscopy, X-ray-induced Auger Spectroscopy and X-ray diffraction, are discussed in detail to correlate the reaction parameters to the composition and morphology of the products. Both TiC and SiC/TiC nanopowders showed a high reactivity to the air exposure, as evinced by the surface oxidation of the particles. Nevertheless, a quite good yield was obtained for nanocomposites of beta-SiC matrix with the addition of up to 20% TiC phase.