Synthesis of chromium carbide (Cr 3C 2) nanopowders by the carbonization of the precursor

Abstract

The solution-derived precursor method was used to synthesize chromium carbide (Cr 3C 2) nanopowders, ammonium dichromate ((NH 4) 2Cr 2O 7) and nanometer carbon black were used as raw materials. The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the single phase Cr 3C 2 can be synthesized under the conditions of 21 wt.% C, 1100 °C and 30 min, and the average crystallite size is 27.2 nm. The powders show good dispersion and are mainly composed of spherical or near- spherical particles with a mean diameter of ~ 30 nm. The surface of the specimen mainly consists of Cr, C and O three species elements. The XPS spectrum of Cr2p consists of two peaks with the binding energies of 577.5 eV and 575.3 eV, which are assigned to the Cr2p 3/2 species of Cr 2O 3 and Cr 3C 2 − x (0 ≤ x ≤ 0.5), respectively. The XPS spectrum of O1s energy region for chromium carbide contains three peaks (Oa, Oh and Od), which are considered to be due to O −, OH − and Cr 2O 3, respectively.