Nanocrystalline zirconium carbide (ZrC) with the size of 1025 nm was synthesized via a co-reduction-carburization process, in which ZrCl4 and CCl4 were used as zirconium source and carbon source, respectively, and metallic Na as reductant in an autoclave at 550 degreesC for 12 h. The samples were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM).