射频等离子体制备球形钨粉研究

采用射频(RF)等离子体对颗粒形状不规则的钨粉球化，研究了加料速率和钨粉分散方式对球化率的影响。通过用电子扫描显微镜(SEM)观测得到的被球化粉末的百分比评估了球化效率。通过对球化处理的钨粉的X射线衍射谱(XRD)的检测，验证了在球化过程中无氧化发生和其它杂质介入。当钨粉以极短暂时间(约几毫秒)快速穿越等离子体炬时，钨粉颗粒因受热而熔化成液滴，快速冷却后，形成致密的球形固态颗粒。

Study on the techniques with using of RF induction plasma for tungsten powders spheroidization

Spherical tungsten particles were obtained by the process of heating irregularly shaped tungsten powders under radio frequency induction plasma (RF induction plasma) condition. The effect of feed rate and different disperse ways on spheroidization efficiency was studied. The efficiency of the spheroidization is evaluated through measurements of the percentage of powder spheroidized based on sweep electron microscopic SEM observations. After detection of the XRD of spheroidized tungsten powder, non-oxidation and no other impurity are verified in the preparation process. During the short flight of the tungsten particles in the plasma flow, about the order of a few milliseconds, the individual particles of the tungsten powder are heated and melted forming a spherical liquid droplet which upon freezing gives rise to the formation of a perfectly dense spherical solid particle.