Synthesis of nanocrystalline titanium carbide alloy powders by mechanical solid state reaction

Abstract

A high-energy ball mill operated at room temperature has been used for preparing titanium carbide (TiC) alloy powders, starting from elemental titanium (Ti) and carbon (C) powders. X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) have been used to follow the progress of the mechanical solid state reaction of Ti and C powders. A complete single phase of fcc-Ti₄₄C₅₆ alloy powders is obtained after a very short milling time (20 ks). The lattice parameter (a ₀ ) of the end product of Ti₄₄C₅₆ was calculated to be 0.4326 nm. The presence of excess starting reactant materials (Ti and/or C atoms) in the final product of the alloy powders could not be detected. The end product of Ti₄₄C₅₆ alloy powders possesses homogeneous, smooth spherical shapes with an average particle diameter of less than 0.5 μm. The internal structure of the particles is marked by fine cell-like features of about 3 nm. On the basis of the results of the present study, the mechanical alloying (MA) process appears to provide a powerful tool for the fabrication of Ti₄₄C{im56} alloy powders at room temperature. The mechanism of mechanical solid state reaction for formation of Ti₄₄C₅₆ alloy powders is discussed.