Synthesis of V8C7–Cr3C2 nanocomposite via a novel in-situ precursor method

Abstract

V8C7–Cr3C2 nanocomposite has been synthesized by a novel in-situ precursor method, and the raw materials are ammonium vanadate (NH4VO3), ammonium dichromate ((NH4)2Cr2O7) and glucose (C6H12O6). The products were characterized by thermogravimetric and differential scanning calorimetry (TG-DSC), X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that V8C7–Cr3C2 nanocomposite with an average crystallite size of 31.5nm can be synthesized at 900°C for 1h. The powders show good dispersion and are mainly composed of spherical or nearly spherical particles with a mean diameter of about 100nm. The weight loss ratio of the precursor throughout the reaction process reaches 70wt.%, and it changes rapidly before 400°C (about 35wt.%). Four endothermic peaks and three exothermic peaks occur during the reaction. The surface of the specimen is mainly composed of V, Cr, C and O four elements. The synthesis temperature of V8C7–Cr3C2 nanocomposite by the method (900°C) is 500°C lower than that of the conventional method (1400°C).