Formation of TiC and SiC refractory compounds by mechanical alloying

Mechanical alloying via high energy ball-mill operated at room temperature has been used for preparing TiC and SiC compounds, starting from elemental Ti, Si and graphite powders. X-ray diffraction, transmission electron microscope, scanning electron microscope and infrared absorption have been used to follow the progress of the mechanical reactions between the reactant materials of Ti-C and Si-C, binary systems. A complete single phase of NaCl-type structure of Ti₄₄C₅₆ compound is yielded after 20 ks of milling. The lattice parameter (a₀) of this compound was calculated to be 0.4326 nm. This end-product of Ti₄₄C₅₆ consists of fine grains of about 5 nm in diameter and possesses homogeneous powders with an average particle diameter of less than 0.5 μm in diameter. In Si-C binary system, a complete stoichiometric β-SiC phase was obtained after 1080 ks of milling. The a₀ for final-product of β-SiC powders was calculated to 0.4357 nm. The existence of transverse optical (TO) and longitudinal optical (LO)-like phonon modes for β-SiC compound are observed. The internal structure of the particles are marked by fine cell-like features of about 6 nm.