In situ synthesis method was used to prepare V8C7–Cr3C2nanocomposite.Ammonium vanadate, ammonium dichromate and nanometer carbon black were used as raw materials.The products were characterized by X-ray diffractometr...In situ synthesis method was used to prepare V8C7–Cr3C2nanocomposite.Ammonium vanadate, ammonium dichromate 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), thermogravimetric and differential scanning calorimetry(TGDSC) and X-ray photoelectron spectroscopy(XPS) techniques.The results show that V8C7–Cr3C2nanocomposite with an average crystallite size of 25.4 nm can be synthesized at 1200 °C for 1 h.The synthesis temperature required by the method is at least 200 °C lower than that required by the conventional approaches for preparing vanadium and chromium carbides.The powders 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 throughout the reaction process reaches 58 wt%.Three exothermic peaks and four endothermic peaks occur during the reaction.The surface of the specimen is mainly composed of V, Cr, C and O elements.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51304063)the Funding Scheme for Young Teachers of Higher School in Henan Province (No. 2013GGJS-076)the Fundamental Research Funds for the Henan Provincial Colleges and Universities (No. 2014YWQQ19)
文摘In situ synthesis method was used to prepare V8C7–Cr3C2nanocomposite.Ammonium vanadate, ammonium dichromate 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), thermogravimetric and differential scanning calorimetry(TGDSC) and X-ray photoelectron spectroscopy(XPS) techniques.The results show that V8C7–Cr3C2nanocomposite with an average crystallite size of 25.4 nm can be synthesized at 1200 °C for 1 h.The synthesis temperature required by the method is at least 200 °C lower than that required by the conventional approaches for preparing vanadium and chromium carbides.The powders 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 throughout the reaction process reaches 58 wt%.Three exothermic peaks and four endothermic peaks occur during the reaction.The surface of the specimen is mainly composed of V, Cr, C and O elements.
