碳辅助氢还原与普通氢还原r制备W粉的对比研究

摘要

在相同的还原工艺参数下,以碳辅助氢还原法和普通氢还原法分别制备W粉,采用XRD、SEM、TEM和HRTEM对不同还原方法制得W粉的物相、形貌和粒度分布进行对比研究,并讨论还原方式对W粉粒径和形貌的影响机理.结果表明:碳辅助氢还原W粉的还原长大机制以固相局部化学反应为主,平均粒径均不超过60 nm,W粉一次颗粒呈均匀细小的球状或椭球状形貌,颗粒间没有明显的团聚或粗化现象;普通氢还原以"挥发-沉积"长大机制为主,所得W粉颗粒粗大,粒径为微米级,发育完全,颗粒呈类球形多面体结构,部分晶粒之间相互交联.%Tungsten powders were prepared by two different methods, respectively, carbon-hydrogen co-reduction method and common hydrogen reduction method, under same reduction process parameter. The phase, morphology and grain size of W powder samples were comparative studied by XRD, SEM, TEM and HRTEM. The effect mechanism of reduction method on the grain size and morphology of tungsten powders was investigated. The results show that the dominant growth mechanism of the carbon-hydrogen co-reduction method is solid phase topochemical reaction. The tungsten grains obtained by the co-reduction method are sphericity or spheroidicity with fine mean size of 60 nm. The agglomeration or coarsening phenomenon between tungsten particles is inconspicuous. The main growth mechanism of the common hydrogen reduction method is volatilization-sedimentation mechanism. The tungsten powders prepared by common hydrogen reduction are full-grown, and the grain morphology is roundish polyhedral. The grain size is micron order, and parts of the grains are bonded mutually.