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 coul d be significantly improved by the incorporation of TiC second phase a nd vice versa. Nanosized TiC and TiC/SiC powders were synthesized by C O2 laser-induced reactions. A TiCl4 and hydrocarbons mixture was irrad iated 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 Aug er Spectroscopy and X-ray diffraction, are discussed in detail to corr elate the reaction parameters to the composition and morphology of the products. Both TiC and SiC/TiC nanopowders showed a high reactivity t o the air exposure, as evinced by the surface oxidation of the particl es. Nevertheless, a quite good yield was obtained for nanocomposites o f beta-SiC matrix with the addition of up to 20% TiC phase.