3. Analysis of Nano/Micro Bimodal SUS316L Powder Behavior

The components fabricated with nanopowder tend to show better surface roughness and mechanical properties with low sintering temperature. However, at the same time, its high price and reactivity are critical problems of nanopowder. Thus, nano/micro bimodal powder has been introduced in powder process to minimize the problems of nanopowder. In this research, the effect of nanopowder content in nano/micro bimodal powder has been investigated. Bimodal powder was prepared with 100-nm and 4-μm-sized stainless steel 316L powder. They were mixed into 5 grades depend on nanopowder volume ratio from 0 to 100%. The apparent and tap density of the powders were measured, and their flowability was compared with Hausner ratio. Unlike theoretical calculation, the tap density of bimodal powders did not show the packing effect due to distribution of nanoparticles. The compaction behavior was also investigated to verify the bimodal packing effect. The result indicated that the bimodal powder with 25 vol. % nanopowder had the highest relative density.