反应温度对纳米碳化钒(V_8C_7)制备的影响

EFFECT OF TEMPERATURE ON PREPARATION OF VANADIUM CARBIDE(V_8C_7) NANOPOWDER

使用偏钒酸铵和纳米炭黑为原料,先制备前驱体粉末,再将前驱体粉末在一定温度下热处理得到纳米V8C7粉末。采用X射线衍射仪(XRD)和扫描电镜(SEM)对不同温度下反应产物的相组成和微观结构进行了分析。结果表明:反应温度对纳米碳化钒制备过程中的相组成和微观结构具有重要影响;随着温度升高,将发生NH4VO3→V2O5→VO2→V5O9+V4O7→V2O3→VC1-x→V8C7的相转变,反应产物的粒度呈增大→减小→增大的变化趋势,1100℃时粉末显示较好的分散性,并且主要由直径100nm左右的球形颗粒组成。

The precursor powder was prepared from the mixture of ammonium vanadate （NH4VO3） and nanometer carbon black. Vanadium carbide （V8C7） nanopowder could be prepared by thermal processing the precursor. The phase composition and microstrueture of the product were analyzed by X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that reaction temperature has important effect on the phase composition and mierostructure during synthesis of vanadium carbide （V8C7 ） nanopowder. With increasing temperature, the following phase transformations NH4VO3→V2O5→VO2→V5O9＋V4O7→V2O3→VC1-x→V8C7 occur, and the particle sizes of the product are changed in order of increasing→decrea- sing→increasing. The powder synthesized at 1100℃ show good dispersiveness and is mainly composed of uniformly-sized spherical particles with a mean diameter of -100 nm.