常压下碳热还原制备碳化钒(V_8C_7)粉末的研究

Study on Preparation of V_8C_7 Powder by Carbon Thermal Reduction under Normal Pressure

为了实现小批量连续化制备碳化钒粉末,以工业级V2O5和纳米碳黑为原料,在常压下氩气保护的碳管炉中高温反应得到了V8C7。采用X射线衍射仪(XRD)、扫描电镜(SEM)、LECO碳氧分析仪对反应产物进行了分析。结果表明:碳化温度为1 450℃时,可得到有序V8C7,但是杂质含量较高;提高温度有利于粉末纯度的提高,而不利于粉末的细化;最终在1 600℃保温4 h的条件下,制备出游离碳质量分数为0.31%、氧质量分数为0.69%、平均粒径为2μm的V8C7粉末。

In order to realize the smallscale continuous production,the V8C7 powder was prepared by the high temperature reaction of industrial grade V2O5 powder and nanometer carbon in the graphite furnace under the argon atmosphere.The reaction product was analyzed by XRD,SEM,and LECO carbon-oxygen analyzer.The result shows that the ordered V8C7 powder is obtained when carbonized at 1 450 ℃.But the impurity content in the V8C7 power is high.Higher reaction temperature has advantage to improve the powder purity but goes against the refinement.When carbonized at 1 600 ℃ for 4 h,the V8C7 powder with 0.31% free carbon,0.69% oxygen（mass fraction）and average particle size of 2 μm is obtained.