Powder particle size is an important factor in the preparation of 316L stainless steel porous materials, which will affect the pore structure and gas permeability. 

The following are the possible effects of powder particle size on the pore structure and air permeability of 316L stainless steel porous materials:

Pore structure: Powder particle size affects the pore size and distribution of porous materials. Finer powder particles generally produce smaller pores, while coarser powder particles produce larger pores. Therefore, the choice of powder particle size can adjust the pore structure of porous materials, thereby affecting its pore size distribution, porosity and pore connectivity.

Pore distribution: The particle size of the powder will also affect the distribution uniformity of the pores of the porous material. Finer powder particles can fill the voids more uniformly, which is conducive to the formation of a uniformly distributed pore structure. Conversely, coarser powder particles may result in an uneven distribution of pores, creating areas of concentrated or aggregated pores.

Air permeability: The particle size of the powder will also affect the air permeability of the porous material. Finer powder particles generally create more pores, increasing the air permeability of porous materials. Coarser powder particles may form larger pores, resulting in lower air permeability.

It should be noted that the effect of powder particle size on porous materials is a complex issue, influenced by the interaction of other factors (such as powder shape, compaction process, etc.). Therefore, when studying the effect of powder particle size on the pore structure and air permeability of porous materials, it is necessary to comprehensively consider other factors and conduct experimental research and data analysis to obtain accurate conclusions and optimization guidance.