粉末粒形对钨粉末注射成形喂料流变性能的影响

Effect of Powder Shape on Rheological Properties of Tungsten Feedstocks for Metal Powder Injection Molding

摘要:

本文采用图像法定量表征了钨粉的粒形与粒度，研究了粉末粒形对钨粉末注射成形喂料流变性能的影响。结果表明：窄粒径钨粉（NPW）与球形钨粉（SW）粒度基本一致；SW比NPW具有更好的球形度、表面光滑度以及分散度。采用相同的有机粘结剂，SW的粉末装载量为64%，高于NPW的59%。与NPW相比，SW喂料表现出更优异的流动性能，具有更低的流动行为指数和粘流激活能，更适合注射成形。粉末粒形影响钨MIM喂料的流变性能主要源于粘结剂与粉末颗粒以及颗粒与颗粒之间的相互作用特性。

Abstract:

In this paper, the particle shape and size of tungsten powders were quantitatively analyzed by image analysis technology, and the effect of particle shape on the rheological properties of tungsten feedstocks for metal powder injection molding (MIM) was alao investigated. The results showed that the particle size of narrow particle-sized tungsten (NPW) powder was almost the same as that of spherical tungsten (SW) powder. In contrast to NPW powders, the SW powders exhibited better sphericity, surface smoothness and dispersion. Mixing with the same binder, the solid loading of SW powders was 64%, which was higher than that of 59% of the NPW powders. The SW feedshocks showed better flow performance, i.e., lower flow behavior index and flow activation energy, and it thus was more suitable for injection molding. Particle shape affects the rheology of tungsten MIM feedstocks by changing the nature of organic binder–particle and particle–particle interactions.