Low temperature synthesis of chromium carbide (Cr3C2) nanopowders by a novel precursor method

摘要

Chromium carbide (Cr3C2) nanopowders have been synthesized by a novel solution-derived precursor method, and the raw materials are ammonium dichromate ((NH4)(2)Cr2O7) and glucose (C6H12O6). The products were characterized by X-ray diffractometry (XRD), thermogravimetric and differential scanning calorimetry (TG-DSC), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that Cr3C2 nanopowders with an average crystallite size of 32 nm can be synthesized at 900 degrees C in 1 h. The powders synthesized by this approach show good dispersion and are mainly composed of spherical or nearly spherical particles with a mean diameter of about 30 nm. The weight loss ratio of the precursor during the reaction is about 55 wt.%, and it reduces rapidly before 400 degrees C (about 45 wt%). The surface of the specimen mainly consists of three elements, Cr, C and O. The XPS spectrum of Cr2p consists of two peaks with the binding energies of 575.8 eV and 577.4 eV, which are assigned to the Cr(2)p(3/2) species of Cr3C2, (0 <= x <= 0.5) and Cr2O3, respectively. 2014 Elsevier Ltd. All rights reserved.