溶胶凝胶纳米WO_3的还原特征

Reducing characteristic of WO_3 nanopowders by sol-gel method

利用溶胶凝胶法制备的纳米WO3粉,研究了一段还原工艺和两段还原工艺下,制备纳米W粉的基本特征;分别用XRD、TEM、FESEM、BET和SAXS(X射线小角度散射法)等手段研究了制备过程中各步骤的产物及最终产物物相组成、颗粒形貌和粒度组成。试验结果表明:一段还原工艺中,可以在700℃、90min的条件下将纳米WO3粉还原为纳米W粉,W粉平均粒度<50nm;两段还原工艺中,在600℃、40min可将纳米WO3粉还原为纳米WO2粉,WO2粉在700℃、90min还原为W粉,W粉平均粒度<38nm;两阶段还原工艺优于一阶段还原工艺,可获得稳定且粒径更小的纳米W粉。

Synthesis characteristic of nanosized tungsten powders reduced from nanosized WO3 powders by sol - gel method under the condition of one - stage reducing process and two - stage reducing process were studied; the powders and the intermediate products were characterized by means of XRD, FESEM,TEM,B. E. T and SAXS（ Xray diffracto-spectrometer/Kratky small angle scattering goniometer） Experimental result shows that nanosized WO3 can be completely reduced to W at 700℃ after 90min in the one- stage reducing process; in the two- stage reducing process, nanosized WO3 can be completely reduced to WO2 at 600℃ after 40min, and WO2 can be reduced to W at 700℃ after 90min, moreover, W particles＇ mean size is less than 40nm; furthermore, the two - stage reducing process of WO3→WO2→W excels the one - stage reducing process of WO3→W and the former can get stable nanosized tungsten powders with less particle size.