Structural Insights: In Situ Synthesis of Titanium Carbide by Magnesiothermic Method Using Carbon Nanotubes and Turbostratic Carbon as Carbon Sources

The current work presents the influence of the magnesiothermic synthesis method on titanium carbide (TiC). In this method, powdered titanium precursors and two carbon sources—turbostratic carbon and carbon nanotubes—were employed in proportions of 10 wt.% and 20 wt.%. The refinement of the X-ray diffraction (XRD) patterns using the Rietveld method for TiC suggests suggested coexistence of two phases, cubic with Fm-3m space group and hexagonal with P3121 space group. In particular, for the sample with 20 wt.% of carbon sources, the XRD refinement revealed that the cubic phase accounted for 94% of the composition, in contrast to a secondary hexagonal phase, Ti6C3.75, which comprised 6%. The influence of carbon on the morphology (particle size and shape) and crystallite size was monitored through bright-field transmission electron microscopy (BF-TEM) imaging and XRD. In samples containing 20 wt.% carbon, a homogeneous morphology in both size (around 11 microns) and shape was observed, along with a reduction in crystallite size (from 22.7 to 17.8 nm). Raman band analysis further revealed vibrational modes indicating that carbon induced disorder in the TiC structure. The magnesiothermic synthesis method developed in this work offers a low-cost approach of interest in the aerospace and automotive industries. Additionally, the study provides significant insights for particles used as additives or reinforcing agents to enhance the mechanical properties of metal matrix composites (MMCs).