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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。
Under the condition of certain temperature and hydrogen flow rate, the mass change of WO3 reduction reaction at different time during WO3 reduction was accurately measured by thermal balance, and the phase identification was carried out by X-ray diffraction (XRD) 0nm) reduction kinetic curve. The reduction kinetic characteristics of WO2 90 prepared from WO3 and W powder prepared from WO2 90 were discussed respectively. The experimental results show that nano-scale WO3 powder can be completely reduced to WO290 (blue tungsten) at 490 ℃ and 37min, while WO290 is completely reduced to W powder at 75 ℃ and 45min. TEM observation shows that the particle size of W powder is less than 80nm.