摘要
在一定的温度和氢气流量条件下 ,用热分析天平精确测量WO3 还原反应过程中 ,不同时间的质量变化 ,并用X射线衍射分析 (XRD)进行物相鉴定 ,绘制纳米级WO3 (粒径≤ 5 0nm)的还原动力学曲线。分别讨论了由WO3 制备WO2 90 及由WO2 90 制备W粉两阶段的还原动力学特征。试验结果表明 :纳米级WO3 粉可以在 4 90℃、37min完全被还原为WO2 90 (蓝钨 ) ,而WO2 90 则在 75 0℃、4 5min完全被还原为W粉。TEM观测表明 ,W粉粒度小于 80nm。
At certain temperature and hydrogen flow rate, the weight changing of tungsten trioxide during the reduction was investigated by thermo balance, and the phase transformation analyzed by means of XRD. To draw the reduction kinetic curves of nanometer WO 3 (particle size less than 50 nm), two stages of WO 3 being reduced to W were studied respectively. The experimental results show that nanometer WO 3 can be completely reduced to WO 290 at 490℃ after 37 minutes, and WO 290 can be reduced to W at 750℃ after 45min. Moreover, TEM result shows that the final W powder particle size is less than 80 nm.
出处
《粉末冶金技术》
CAS
CSCD
北大核心
2002年第3期147-150,共4页
Powder Metallurgy Technology
基金
国家自然科学基金资助项目 (编号 :5 0 0 74 0 0 7)
关键词
纳米级
氧化钨
还原
动力学曲线
nano-meter
tungsten trioxide
reduction
kinetics
