纳米V_8C_7粉末的制备  

Preparation of nanometer V_8C_7 powder

作　　者：吴恩熙[1] 颜练武[1] 钱崇梁[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2005年第5期771-775,共5页Journal of Central South University:Science and Technology

基　　金：国家高技术研究发展计划资助项目(2002AA331090)

摘　　要：将V2O5溶解于有机酸溶液中, 通过喷雾干燥制得非晶态含钒的粉末前驱体, 将前驱体粉末还原/碳化后得到V8C7粉末. 采用X射线衍射仪﹑扫描电镜﹑透射电镜﹑碳氧分析仪对工艺过程产品进行分析. 结果表明: 前驱体是粒度为10～20 μm非晶态球形粉末, 当温度升高到400 ℃时, 前驱体粉末开始分解;当温度升高到600 ℃时, 前驱体粉末全部转变为V2O3与游离C原子级别混合均匀的复合粉末;随着温度的升高, 游离C还原碳化V2O3, 当温度升高到800 ℃时, 出现V4C3相;在约1 100 ℃时, 得到相成分均一的V8C7粉末, 其形貌是粒径为30～50 nm的一次颗粒形成的多孔空壳球形, 其总C含量为17.38%, 游离C含量为0.47%. 前驱体粉末在加热过程中相成分转变过程为: V2O3→V4C3→V8C7, 不经历V2O3 转变为VO的过程.Dissolving V2O5 in organic acid solution, the amorphous powder precursor which contained vanadium was obtained by spray drying, and the nanometer V8C7 powder was prepared through reduction/carbonization of the precursor powder. The technological process was investigated and analyzed using X-ray diffractometer, scanning electron microscope （SEM）, transmission electron microscope （TEM） and carbon ＆ oxygen analyzer. The results show that the pre- cursor is amorphous spherical powder of 10 - 20μm. When the temperature rises to 400℃ in vacuum, the precursor begins to decompose; when the temperature rises to 600℃, all the precursor powder is transformed into the composite powder in which V2O3 mixes with free carbon homogeneously atom-level; V2O3 is reduced and carbonized by free carbon with the temperature, and when the temperature goes up to 800℃, the V4C3 phase occurs. At about 1 100 ℃, the VC7 powder is obtained with single phase, and its morphology is of porous hollow sphere formed by many first particles of 30 - 50 nm. The total carbon content is 17.38% and the free carbon content is 0.47%. In the process of reduction/carbonization, the precusor powders undergo the following phase transformation： V2O3→V3C3→V8C7, without undergoing the process of phase transformation from V2O3 into VO phase.

关 键 词：碳化钒 纳米 喷雾干燥 还原/碳化 晶粒抑制剂 

分 类 号：TF123[冶金工程—粉末冶金]